WO2016163339A1 - Stent - Google Patents

Abstract

Provided is a stent with which characteristics required from a stent can be achieved at higher levels, and which has a novel structure. A stent 10 is provided with a tubular framework 16 capable of radial expansion/contraction, wherein the framework 16 includes a core layer 18 formed from biodegradable material, and a core degradation control layer 20 formed from biodegradable material is layered on a surface of the core layer 18 of the framework 16. Alternatively, a framework 52, 54 is provided with a self-extending region 56 that deforms into a pre-set shape by superelasticity, wherein a portion of the framework 52,54 away from the self-extending region 56 in the axial direction forms an over-deformation region 58 capable of greater deformation than the self-extending region 56.

Description

Stent

The present invention relates to a stent that is inserted and placed in a body lumen such as a blood vessel.

Conventionally, when an abnormality such as stenosis or occlusion occurs in a lumen of a blood vessel or the like, for example, a stent treatment is performed in which a stent is inserted into the lumen and the lumen is held in an expanded state. For example, as described in Japanese Patent Application Laid-Open No. 2007-267844 (Patent Document 1) and the like, the stent has a cylindrical shape as a whole, and has a small diameter when inserted into the lumen. The diameter is expanded in place.

By the way, there are various types of stents such as prevention of restenosis of the body lumen, ease of positioning to the stenosis site in the body lumen, and allow deformation according to the curvature or branching of the indwelling site in the body lumen. Performance is required. Therefore, a biodegradable stent that can be decomposed and absorbed by living tissue has been developed as a stent that can suppress the occurrence of restenosis, and self-expanding that is easy to position to a predetermined position by self-expandability due to superelasticity etc. Stents are also being developed.

However, there are cases where the required characteristics cannot be sufficiently achieved with various types of stents having a conventional structure, and further improvements in the performance of these stents are required.

Conventionally, when an abnormality such as stenosis or occlusion occurs in a lumen of a blood vessel or the like, for example, a stent treatment is performed in which a stent is inserted into a stenosis site in the lumen and the lumen is held in an expanded state. ing. This stent enables expansion / contraction deformation, and in consideration of reduction of burden on the living body and improvement of biofusion, as described in, for example, JP-A-2007-267844 (Patent Document 1), A skeletal structure such as a mesh shape or a coil shape is adopted, and many window-like gaps that open through the peripheral wall portion inward and outward are provided.

By the way, if the tissue forming the stenosis is a soft atheroma, the atheroma may re-extrude through the gap between the struts forming the skeleton structure of the stent, and there is a possibility that restenosis may occur at the stent placement position. It was. In addition, the atheroma that re-projected to the inner peripheral side of the stent diffused downstream of the stent placement position due to blood flow, and there was a risk that restenosis would occur downstream of the stent placement position.

Therefore, in Japanese translations of PCT publication No. 2004-522494 (Patent Document 2), the second stent is delivered to the inside of the first stent previously placed in the blood vessel and overlapped with the inner periphery of the first stent. A technique for relocating is disclosed. In this prior art, it is said that the edema which re-projects through the clearance of a 1st stent can be suppressed with the 2nd stent indwelled later.

However, in the conventional technique described in Patent Document 2, since it is necessary to place the second stent in the first stent after a predetermined period of time after placing the first stent, the operation of placing the stent multiple times. This was a heavy burden on the patient.

Conventionally, when an abnormality such as stenosis or occlusion occurs in a lumen such as a blood vessel, the stent is delivered to a lesion in the lumen using, for example, a stent delivery catheter, and the stent is expanded and pressed against the lumen wall. Thus, stent treatment for holding the lumen in an expanded state is performed. The stent has a small diameter when inserted into the lumen, but is expanded and placed in the lumen. As a method for expanding the diameter of the stent in the lumen, there are self-expansion using a shape memory material and mechanical expansion, and expansion using a balloon.

That is, when a stent is delivered by a delivery catheter, the balloon is folded with respect to the distal end portion of the catheter shaft as in the stent described in JP-A-2008-55187 (Patent Document 3). At the same time, the stent is externally attached to the folded balloon. Then, by inserting the distal end portion of the stent delivery catheter into the lesioned part in the lumen and expanding the balloon, the stent extrapolated to the balloon is expanded in diameter and pressed against the lumen wall. Thereafter, the stent is placed in the lumen by deflating the balloon and withdrawing the catheter.

However, since the stent expanded by such a balloon is exposed to the outer peripheral surface during delivery, the stent and the lumen wall come into contact with each other. There was a risk that the stent would fall out of the balloon due to shear stress in the opposite direction.

In addition, in order to prevent restenosis of the lumen due to the placement of the stent, a stent in which a recess or the like is provided in the stent strut and a drug or the like exhibiting, for example, a cell growth inhibitory effect is carried in the recess is also proposed. For example, Japanese Patent Application Laid-Open No. 2009-22771 (Patent Document 4) also mentions such a stent.

That is, in the stent described in Patent Document 4, a through hole is provided in the stent strut, and a drug is accommodated in the through hole. Then, in the through hole, the opening on the inner peripheral side of the stent is substantially closed to prevent the drug from diffusing into the lumen, so that the drug can enter the lumen wall through the opening on the outer peripheral side of the stent when the stent is placed. Stable and sustained release.

However, in the stent described in Patent Document 4, since the drug is spontaneously released, the release rate is slow, and a large amount of the drug contained in the recess remains in the bottom portion of the recess. There was a risk that the drug would not be released sufficiently to the lumen wall.

JP 2007-267844 A JP-T-2004-522494 JP 2008-55187 A JP 2009-22971 A

The inventions described in claims 1 to 6 are based on the circumstances described in the above-mentioned [0002] to [0004], and are capable of adjusting the degradation rate by a living body with a greater degree of freedom. An object of the present invention is to provide a stent having a novel structure.

The inventions described in claims 7 to 12 are based on the circumstances described in [0002] to [0004] described above, and set the deformed shape with a greater degree of freedom. An object of the present invention is to provide a stent having a novel structure that can be used.

The inventions described in claims 13 to 20 are made in the background of the circumstances described in the above [0005] to [0008], and the problem to be solved is that the patient or practitioner is excessive. An object of the present invention is to provide a stent having a novel structure capable of effectively preventing restenosis of a body lumen while avoiding a burden.

The inventions described in claims 21 to 29 are made in the background of the circumstances described in the above [0009] to [0014], and the problem to be solved is, for example, insertion into a lumen. A novel structure stent with a specific configuration that may be effective to prevent the balloon from dropping off more effectively or to release the loaded drug more effectively to the outside. The purpose is to provide

1st aspect of this invention is a stent provided with the cylindrical frame | skeleton which can be expanded / contracted in a radial direction, Comprising: While the said frame | skeleton has a core layer formed with the biodegradable material, this core layer in this frame | skeleton A core decomposition control layer made of a biodegradable material is laminated on the surface of the substrate.

In a stent having a structure according to this aspect, the time required for biodegradation of the stent can be set with a large degree of freedom by adjusting the biodegradation rate of the core layer of the skeleton with the laminated core decomposition control layer. Therefore, it is possible to secure a sufficient expansion support period for the stenosis site by the placed stent, and risks such as inflammation of the body lumen and associated restenosis due to the stent being placed over a long period of time. Can also be reduced.

In addition, by appropriately selecting each forming material of the core layer and the core degradation control layer, it is possible to reduce the influence of the product of the biodegradation reaction of the core layer and the core degradation control layer on the living tissue such as the blood vessel wall. it can. Specifically, when the core layer and the core decomposition control layer are composed of a combination of magnesium and poly-L-lactic acid, water ions generated when magnesium is decomposed are water generated during biodegradation of poly-L-lactic acid. Neutralization with oxide ions reduces the influence of hydrogen ions on living tissues.

A second aspect of the present invention is the stent according to the first aspect, wherein the core decomposition control layer is laminated on both the inner peripheral surface and the outer peripheral surface of the core layer.

In the stent having a structure according to this aspect, the core degradation control layer covers both surfaces of the core layer, whereby the biodegradation of the core layer can be controlled more effectively. In addition, since both surfaces of the core layer are protected by the core decomposition control layer, damage and deterioration of the core layer can be suppressed.

A third aspect of the present invention is the stent according to the first or second aspect, wherein the core layer is formed of one of a biodegradable metal and a biodegradable resin, and the core decomposition The control layer is formed of either the biodegradable metal or the biodegradable resin.

In the stent having a structure according to this aspect, by adopting a biodegradable metal and a biodegradable resin having different properties laminated, it is possible to realize a target characteristic with a greater degree of freedom. For example, if the core layer is formed of a biodegradable metal and the core decomposition control layer is formed of a biodegradable resin, the core layer constituting the main part of the skeleton is made a relatively high strength metal material. The stenosis part of the body lumen can be stably maintained in an expanded state. Further, for example, if the core layer is formed of a biodegradable resin and the core decomposition control layer is formed of a biodegradable metal, the resin core layer can be protected by the metal core decomposition control layer, The biodegradation rate of the resin-made core layer that is relatively easily decomposed can be adjusted by a metal core-decomposing control layer that is relatively difficult to decompose.

A fourth aspect of the present invention is a stent according to any one of the first to third aspects, wherein the core layer has a multilayer structure.

In the stent having a structure according to this aspect, the skeleton characteristics can be adjusted with a greater degree of freedom by making the core layer a multilayer structure. Specifically, for example, if the core layer has a multilayer structure in which a plurality of biodegradable metal layers and biodegradable resin layers are alternately laminated, the biodegradation rate can be adjusted with higher accuracy, It may be possible to provide flexibility and easily cope with bending or bending of the body lumen. In addition, for example, if a core layer in which a plurality of types of biodegradable resin layers with different biodegradation rates, hardnesses, and supported drugs are laminated is used, the complex required for a stent depending on the lesion It is also possible to realize the characteristics as appropriate.

A fifth aspect of the present invention is a stent according to any one of the first to fourth aspects, wherein the skeleton has a contrast layer formed of a radiopaque material.

The stent having a structure according to this aspect has a contrast layer that exhibits high visibility under X-ray fluoroscopy, so that the position of the stent can be easily confirmed in stent placement under X-ray fluoroscopy.

In addition, if the contrast layer is made of a stable material that is difficult to biodegrade, such as gold or platinum, even if the skeleton of the stent is biodegraded and disappears, the contrast layer remains in the body. By this, it is possible to confirm the trace where the stent is placed. In addition, since the contrast layer is not required to have a strength capable of maintaining the structure against an external force like a skeleton of a stent, it can be a thin film, and the contrast layer can be formed of a material that is not biodegradable. The effect on living tissue is extremely small. In particular, by selecting a material having excellent biocompatibility such as gold or platinum, residual in vivo is not a problem.

A sixth aspect of the present invention is the stent according to any one of the first to fifth aspects, wherein the core layer and the core decomposition control layer are at least one of spraying, vapor deposition, etching, and electroforming. It is formed by.

In a stent having a structure according to this aspect, a stent having a laminated structure including a core layer and a core degradation control layer can be easily manufactured with a good yield.

According to a seventh aspect of the present invention, there is provided a stent having a cylindrical skeleton capable of expanding and contracting in the radial direction, the skeleton including a self-expanding region that is deformed into a preset shape by superelasticity, and the skeleton. A portion of the self-expanding region that is off in the axial direction is an over-deformation region that can be deformed larger than the self-expanding region.

In the stent having a structure according to this aspect, in the self-expanding region, rapid expansion to a preset shape based on superelasticity is realized, and excellent shape retention characteristics after expansion can be obtained. On the other hand, the over-deformation region can be appropriately deformed according to the shape of the indwelling site by mechanical expansion using a balloon or a mechanical device, and is particularly allowed to be deformed larger than the self-expansion region. , The degree of freedom in setting the shape is great. The stent skeleton is composed of such self-expanding regions and over-deformed regions having mutually different characteristics, which greatly increases the degree of freedom of shape when the stent is placed and the shape stability when it is placed. Can be set with degrees of freedom.

An eighth aspect of the present invention is the stent according to the seventh aspect, wherein at least one end in the axial direction of the skeleton is the over-deformed region.

In the stent having the structure according to this aspect, the axial end of the skeleton is pressed against the lumen wall by, for example, expanding and deforming the hyperdeformed region so as to have a larger diameter than the self-expanding region. The position and the indwelling posture are stably maintained, and the flow of blood and the like is prevented from stagnation due to the gap between the axial end of the stent and the lumen wall, and thrombus generation is suppressed.

A ninth aspect of the present invention is the stent according to the seventh or eighth aspect, wherein the over-deformed region can be expanded and deformed to a larger diameter than the self-expanding region.

In the stent having the structure according to this aspect, the hyperdeformation region can be expanded and deformed to have a larger diameter than the self-expansion region. The diameter of the stenosis portion can be increased. Furthermore, even when the stenosis of the lumen is not sufficiently expanded by the superelasticity of the self-expanding region due to calcified lesions or arteriosclerosis, the hyperdeformation region can be expanded to a larger diameter than the self-expanding region. By this, it may be possible to push the stenosis site with a greater force.

A tenth aspect of the present invention is the stent according to any one of the seventh to ninth aspects, wherein the over-deformed region is expanded by a balloon so as to be deformable to a greater extent than the self-expanding region. It is what.

In the stent having the structure according to this aspect, the hyperdeformed region can be easily deformed into a shape corresponding to the lumen shape by expanding the balloon, and the stenotic site can be adjusted by adjusting the internal pressure of the balloon. It is possible to accurately apply an appropriate force to.

Moreover, according to the balloon expansion, the over-deformed region is not only greatly deformed in the radial direction with respect to the self-expanded region, but also the stent is bent or curved by largely deforming in the axial direction. It is also possible to deform with a large degree of freedom in accordance with the shape. For example, deformation as in the following eleventh aspect can also be realized.

An eleventh aspect of the present invention is the stent according to the tenth aspect, wherein a gap in the peripheral wall portion of the over-deformation region is expanded by the balloon and can be deformed to be larger than a gap in the self-expansion region. It is what.

A stent having a structure according to this embodiment is used when a stent is placed at a branching site of a lumen by pushing a gap between struts in an over-deformed region having a plurality of annular shapes, mesh shapes, spiral shapes, or the like with a balloon. Can also be suitably employed. Note that it is also possible to insert another stent into the branch lumen through the gap in the hyperdeformed region pushed and expanded by the balloon.

A twelfth aspect of the present invention is the stent according to any one of the seventh to eleventh aspects, wherein the self-expanding region and the overdeformed region are at least one of spraying, vapor deposition, etching, and electroforming. It is formed by one.

In the stent having the structure according to this aspect, a stent having a structure including a self-expanding region and an overdeformed region can be easily manufactured with a good yield.

A thirteenth aspect of the present invention is a peripheral wall structure in which a first skeleton structure provided with a first gap and a second skeleton structure provided with a second gap are integrated so as not to be separated. The stent is characterized in that the second gap in the second skeleton structure is reduced by the first skeleton structure.

According to the stent having the structure according to this aspect, the composite peripheral wall in which the first skeleton structure having the first gap and the second skeleton structure having the second gap are integrated so as not to be separated from each other. It is structured. Therefore, for example, the second skeletal structure ensures the strength of supporting the peripheral wall of a lumen such as a blood vessel, while the first skeletal structure reduces the second gap to effectively re-protrude the plaque after placement of the stent. It is also possible to suppress it.

In particular, the stent according to this aspect has a peripheral wall structure in which the first skeleton structure and the second skeleton structure are integrated so as not to be separated from each other. As described above, a plurality of operations such as placing the second stent after placing the first stent are not required, and the stent is placed in the lumen by one operation. Thereby, a burden of a patient or a practitioner can be reduced with certainty.

In a fourteenth aspect of the present invention, in the stent according to the thirteenth aspect, the first skeletal structure is meshed, while the second skeletal structure is folded back in the length direction in the circumferential direction. The first skeleton structure is integrated and positioned on the inner peripheral side of the second skeleton structure.

According to the stent having the structure according to the present aspect, since the first skeleton structure on the inner peripheral side is mesh-like, the gap opened to the inner peripheral side is relatively small, and the inner peripheral surface of the stent is The curved surface has few irregularities. This suppresses stagnation and turbulence such as blood flow that flows in the stent while the stent is placed in the lumen, thereby forming thrombus and adhering to the inner peripheral surface of the stent. Restenosis can be more effectively suppressed.

On the other hand, the second skeleton structure on the outer peripheral side has a coil shape extending in the circumferential direction while being folded back in the axial direction, and the gap opening on the outer peripheral side is relatively large, and the outer peripheral surface of the stent is accompanied by the skeleton structure. Unevenness is formed larger than the inner peripheral surface. Thereby, when the stent is placed in the lumen, the convex portion on the outer peripheral surface is pressed so as to bite into the lumen wall, so that the stent positioning effect by the convex portion can be improved. In addition, the second skeleton structure in this aspect includes, for example, a structure in which a plurality of coiled cells extending annularly in the circumferential direction are arranged in series in the axial direction and are connected to each other by a link to form a tube shape. For example, a coiled structure that extends at a predetermined lead angle and is connected in a spiral shape may be employed.

According to a fifteenth aspect of the present invention, in the stent according to the thirteenth aspect, the first skeleton structure has a mesh shape, while the second skeleton structure is folded in the length direction in the circumferential direction. The first skeleton structure is integrated with the first skeleton structure positioned at the middle portion in the thickness direction of the second skeleton structure.

According to the stent having the structure according to this aspect, the mesh-shaped first skeleton structure is positioned in the middle portion in the thickness direction so as to enter the coil-shaped second skeleton structure. Compared with the case where the skeleton structure and the second skeleton structure are overlapped on the inside and outside, the thickness dimension (diameter dimension) of the stent can be kept small. Thereby, inhibition of blood flow and the like when the stent is placed in the lumen can be suppressed, and lumen restenosis associated with adhesion of thrombus or the like to the inner peripheral surface of the stent can be more effectively prevented.

Further, as the first and second skeletal structures constituting the stent of the present invention, the following modes can also be adopted.

According to a sixteenth aspect of the present invention, in the stent according to the thirteenth aspect, each of the first skeleton structure and the second skeleton structure is meshed, and these first skeleton structures And the second skeleton structure are superposed in the thickness direction of the peripheral wall.

According to a seventeenth aspect of the present invention, in the stent according to the thirteenth aspect, each of the first skeleton structure and the second skeleton structure has a coil shape extending in the circumferential direction while being folded back in the axial direction. The first skeleton structure and the second skeleton structure are superposed in the thickness direction of the peripheral wall.

For example, when the second stent is placed after placement of the first stent as in the conventional structure described in Patent Document 2, the skeletal structures of both stents overlap at the same position, and the gap is not reduced. However, in the stent of the sixteenth and seventeenth aspects according to the present invention, the same skeletal structure in the form of mesh or coil is used as the first and second skeletal structures. Even when employed as a skeletal structure, the desired effect can be stably obtained by reliably reducing the gap by being integrated in advance.

Therefore, according to the stent having the structure according to the sixteenth and seventeenth aspects, for example, the same structure can be adopted as the first skeleton structure and the second skeleton structure.

In addition, according to the stent according to the sixteenth and seventeenth aspects, even if the strength of the single skeleton structure is insufficient, not only the two but also the two can be integrated with each other. Thus, it is possible to efficiently ensure strength and rigidity while avoiding an increase in thickness dimension. Moreover, even if it is difficult to achieve with a mesh-like or coil-like skeleton structure with a small gap, it is realized by considering the selection of the first skeleton structure and the second skeleton structure and the mutual integration conditions. Therefore, the degree of freedom for setting the characteristics of the stent can be greatly secured.

According to an eighteenth aspect of the present invention, in the stent according to the sixteenth or seventeenth aspect, the first gap in the first skeleton structure is made small in the second skeleton structure, and In the second skeleton structure, the second gap is made smaller in the first skeleton structure.

According to the stent having the structure according to this aspect, for example, the gap between the first skeleton structure and the second skeleton structure is reduced, so that the effect of reducing the gap due to the combination of the skeleton structure is further increased. Can be achieved efficiently.

According to a nineteenth aspect of the present invention, in the stent according to the sixteenth to eighteenth aspects, the first gap in the first skeleton structure is smaller than the second gap in the second skeleton structure. And the second skeleton structure is superimposed on the outer peripheral side of the first skeleton structure.

According to the stent having the structure according to this aspect, the inner circumferential surface has a smaller axial interval on the inner circumferential side than the outer circumferential side, that is, the gap in the skeletal structure. On the other hand, large irregularities can be formed on the outer peripheral surface. Thereby, the effect of suppressing the occurrence of thrombus or the like to prevent restenosis of the lumen and the positioning effect of the stent due to the convex portion of the outer peripheral surface biting into the lumen wall can be more effectively exhibited.

According to a twentieth aspect of the present invention, in the stent according to the thirteenth to nineteenth aspects, at least one of the first skeleton structure and the second skeleton structure is integrated with each other by electroforming or etching. It is formed with a different structure.

According to the stent having a structure according to this aspect, compared to laser cutting or the like, since the discarded portion can be reduced, the yield can be improved and the shape and material can be adjusted as appropriate. The degree of design freedom can be improved.

In particular, when adopting a mesh-like tube as the first skeleton structure or the second skeleton structure, troublesome ends such as joining at the tube opening end by adopting those formed by electroforming or etching It is also possible to eliminate the need for partial processing.

In addition, when adopting a structure in which the first skeleton structure and the second skeleton structure are overlapped in the thickness direction of the stent peripheral wall so as to be sandwiched between the inner periphery side, the outer periphery side, or the intermediate portion in the thickness direction, appropriate masking, etc. It is possible to form the first skeleton structure and the second skeleton structure continuously and integrally by electroforming or etching. As a result, the stability of the characteristics and the reliability can be greatly improved as compared with the fixation of the first skeleton structure and the second skeleton structure by ex-post adhesion or welding.

According to a twenty-first aspect of the present invention, in a stent that is attached to a balloon and delivered to a lumen, a balloon linking protrusion that protrudes from the surface of a strut constituting the peripheral wall and cooperates with the balloon is provided. Stent.

According to the stent having the structure according to this aspect, the balloon linking protrusion protruding from the surface of the strut can be linked to, for example, locked or frictionally contacted with the balloon, The joint action is performed by deforming in response to the expansion deformation. Therefore, in the stent according to the present invention, any problem that has been a problem in the prior art, such as a good positioning action with respect to the surface of the balloon or a reduction action of the remaining drug solution when releasing the drug in the body lumen. The technical effect that can effectively solve the problem can be exhibited.

According to a twenty-second aspect of the present invention, in the stent according to the twenty-first aspect, an inner circumference in which the balloon linkage protrusion is formed on an inner circumferential surface of the strut and is locked by a linkage action with respect to the balloon. It is comprised by the connection protrusion.

According to the stent having the structure according to this aspect, the balloon linkage projection locked to the inner peripheral side of the strut is locked to the outer peripheral surface of the balloon by the balloon linkage action in the mounted state on the balloon. The As a result, even when the axial displacement force is exerted on the stent due to friction with the lumen wall as it is passed through the lumen, the balloon linkage protrusion is caught on the balloon, so that the mounting state on the balloon is reduced. It is maintained and displacement on the balloon can be effectively prevented.

In particular, by providing such a balloon linkage protrusion, the retention force of the stent on the balloon is improved, so that the caulking force of the stent at the time of mounting on the balloon can be reduced, for example. Thereby, the flexibility of the stent can be improved, and it is also possible to improve the follow-up deformation performance with respect to the bent lumen at the distal end portion of the stent, and thus the delivery catheter to which the stent is attached.

According to a twenty-third aspect of the present invention, in the stent according to the twenty-first or twenty-second aspect, the balloon linking protrusion is a protruding piece protruding from the surface of the strut, and the linking action to the balloon is As the balloon is expanded and deformed, the balloon linking projection is deformed and superimposed on the surface of the strut.

According to the stent having the structure according to this aspect, the balloon linkage protrusion is deformed and superimposed on the surface of the strut as the balloon is expanded and deformed, and the protrusion amount of the protrusion-like balloon linkage protrusion is obtained. By reducing the size, it is possible to enjoy a special technical effect utilizing the deformation of the balloon linkage protrusion.

In particular, for example, when the balloon linkage protrusion is provided so as to protrude on the inner peripheral side of the strut or on both sides in the axial direction, the balloon linkage protrusion is deformed in the overlapping direction on the strut surface as the balloon is expanded. Thereby, the protrusion height of the balloon-linked protrusion from the strut surface into the body lumen is reduced in the indwelling state in the body lumen. As a result, the surface of the stent exposed in the body lumen is made smoother, so that blood vessels and the like associated with the formation of thrombus due to blood stagnation and turbulence, etc., and adhesion of the thrombus to the stent surface, etc. Luminal restenosis can be effectively prevented.

Further, for example, when the balloon linkage protrusion is provided so as to protrude from the inner peripheral surface of the strut, it is possible to reduce the diameter expansion force exerted from the balloon to the strut by the deformation of the balloon linkage protrusion. It is also possible to reduce a rapid force exerted on the peripheral wall of the lumen. Alternatively, when the balloon linking projection is provided so as to protrude from the outer peripheral surface of the strut, the protruding tip of the balloon linking projection first comes into contact with the peripheral wall of the body lumen when expanding the diameter. It is also possible to obtain the action, and when placing in the lumen after the diameter expansion, the expansion force of the strut is also effectively applied to the lumen by deforming the balloon linkage protrusion so as to overlap the outer surface of the strut. Can be exerted.

In this embodiment, the balloon linkage protrusion and the strut surface do not have to be completely closely overlapped with each other, and may be overlapped leaving a certain gap. That is, the effect as described above can be exhibited if the distance between the balloon linkage protrusion and the inner peripheral surface of the strut after the balloon expansion becomes smaller than before the balloon expansion.

In this embodiment, the deformation of the balloon linkage protrusion is preferably plastic deformation. However, the deformation of the balloon linkage protrusion in the present invention is not limited to plastic deformation, and may be elastic deformation. . However, even in the case of plastic deformation, it is not necessary to maintain the completely deformed state, and the deformation may be performed to such an extent that the original shape is not restored.

In this aspect, the deformation of the balloon linking protrusion is not limited to the form of being deformed by being pressed to the outer peripheral side as the balloon is expanded as described above. The balloon linking protrusion is not limited to the expansion of the balloon. What is necessary is just to deform | transform with it. That is, even if the balloon-linked protrusion protruding from the strut surface is directly pressed by the balloon and is not subjected to a deforming external force, for example, it protrudes at an angle from any surface of the strut. It is also possible to use a deformation or the like that occurs so that the base end portion falls in the direction of overlapping with the strut surface with the base end portion as a hinge.

According to a twenty-fourth aspect of the present invention, in the stent according to any one of the twenty-first to twenty-third aspects, the strut is provided with a drug-accommodating recess in which a drug is accommodated, and is associated with the balloon. As the balloon is expanded and deformed, the balloon linking projection is deformed to reduce the volume of the medicine-receiving recess and allow the medicine to be discharged to the outside.

According to the stent having the structure according to this aspect, when the balloon is expanded and deformed and the stent is indwelled in the lumen, the balloon linkage protrusion is deformed by the linkage action with respect to the balloon, and the volume of the drug containing recess is reduced. By reducing the amount, the medicine is brought out of the medicine housing recess. That is, like the conventional structure described in Patent Document 4, when the stent is placed in the lumen, it is positively released to the outside of the drug containing recess. The residue of the drug in the drug receiving recess can be effectively reduced. In addition, the medicine accommodating recess may be opened in any direction on the strut surface, or may be opened in a plurality of directions.

In a twenty-fifth aspect of the present invention, in the stent according to the twenty-fourth aspect, the drug containing recess is provided to open on the outer peripheral surface of the strut, and the balloon linking protrusion is the balloon. It is comprised by the outer periphery connection protrusion which deform | transforms with this expansion deformation | transformation, enters into this chemical | medical agent accommodation recess, and discharges | emits this chemical | medical agent.

According to the stent having the structure according to the present aspect, since the drug containing recess is provided to open on the outer peripheral surface of the strut, the balloon is expanded on the outer wall of the lumen along with the expansion of the balloon. Is released towards. Thereby, the chemical | medical agent accommodated in the chemical | medical agent accommodation recess can be made to act directly with respect to a lumen wall. In addition, the outer periphery connection protrusion which concerns on this aspect can also be employ | adopted together with the inner periphery connection protrusion which concerns on the said 22nd aspect, for example.

According to a twenty-sixth aspect of the present invention, in the stent according to the twenty-fourth aspect, the drug containing recess is provided through the strut in the thickness direction, and the balloon linking protrusion is formed on the balloon. It is constituted by an extruding portion that is deformed along with the expansion deformation and enters the drug containing recess from the inner peripheral side of the strut.

According to the stent having the structure according to this aspect, since the drug containing recess is provided through the strut, it is also possible to set a large amount of drug in the drug containing recess. In addition, the balloon linkage protrusion may be provided so as to protrude from the stent to the inner peripheral side and be positioned by a locking action to the balloon.

According to a twenty-seventh aspect of the present invention, in the stent according to the twenty-fourth to twenty-sixth aspects, the balloon linkage protrusion is configured to fit into the drug-receiving recess.

According to the stent having the structure according to this aspect, when the balloon is expanded, the balloon linking protrusion is fitted into the drug receiving recess, so that the balloon linking protrusion from the stent surface is suppressed in height and the drug is stored. It is possible to efficiently secure the amount of medicine contained in the recess. The insertion of the balloon linkage protrusion into the drug receiving recess gradually progresses with the pressure of the body lumen wall and the decrease in the stored drug solution after placement of the stent, thereby actively releasing the drug solution. It is possible to carry out over a predetermined period, and the balloon linkage is secured while securing the initial amount of drug solution by fitting the balloon linkage projection into the medicine receiving recess when the balloon is expanded. By setting the residual volume in the medicine housing recess with the protrusions fitted, it is possible to set so that the drug solution remaining there is released over time. In this embodiment, it is possible to make such various settings, and thereby control the release of the chemical solution over time.

According to a twenty-eighth aspect of the present invention, in the stent according to the twenty-first to twenty-seventh aspects, a lumen of a catheter in which the balloon linkage protrusion is attached to the balloon from the inner or outer surface of the strut. It projects inclining toward the direction opposite to the traveling direction inside.

According to the stent having the structure according to this aspect, when delivering to a target site in the body lumen, the axial displacement on the balloon due to the provision of the balloon linking projection protruding from the surface of the strut Can be effectively suppressed. In other words, in the balloon linkage protrusion provided on the outer peripheral surface of the strut, a protruding direction that avoids being caught in the body lumen can be set, and in the balloon linkage protrusion provided on the inner peripheral surface of the strut, the engagement with the balloon is possible. The rearward displacement on the balloon sent into the lumen by the stopping action can be suppressed.

According to a twenty-ninth aspect of the present invention, in the stent according to the twenty-first to twenty-eighth aspects, the balloon linkage protrusion is integrally formed on the surface of the strut by at least one of electroforming and etching. It is.

According to the stent having the structure according to the present invention, since the balloon linking protrusion is formed integrally with the strut surface by electroforming or etching, the stent having a shape that is difficult to achieve by conventional laser cutting or the like is manufactured. May also be feasible. In addition, the connecting part between the strut and the balloon linking projection can be formed stably with good accuracy while being a fine part compared to the case of post-processing, and the stability of the desired effect Can also be achieved.

According to the first to sixth aspects of the present invention, the stent skeleton has a structure in which the core decomposition control layer formed of the biodegradable material is laminated on the surface of the core layer formed of the biodegradable material. Thus, the biodegradation rate of the core layer can be adjusted by the core decomposition control layer, and the indwelling period of the stent in the body can be set with a high degree of freedom and accuracy.

In the seventh to twelfth aspects of the present invention, the skeleton of the stent is constituted by a self-expanding region that automatically expands by superelasticity, and an overdeformed region that is mechanically deformed by a balloon or the like, The overdeformation region can be deformed larger than the self-expansion region. Therefore, the self-expanding region realizes rapid deformation to the initial shape and maintenance of the stenotic region in the expanded state due to the shape stability after deformation, while the hyperdeformation region allows the shape of the lumen to be maintained. It is possible to deform with a large degree of freedom according to the above, and to cope with various indwelling sites.

According to the thirteenth to twentieth aspects of the present invention, the first skeletal structure and the second skeleton structure are combined and integrated to form a small gap efficiently and stably. Problems such as protrusion of plaque through the gap and restenosis of the lumen can be effectively prevented. Further, since the stent having such a small gap can be placed in the lumen of the patient by one operation, the burden on the patient and the practitioner can be surely reduced.

According to the twenty-first to twenty-ninth aspects of the present invention, positioning at the time of delivery to a predetermined site in a body lumen is provided by providing a balloon linking projection that acts in conjunction with the balloon on the surface of the strut. It is possible to realize a strut having a novel structure capable of exhibiting special effects as needed, which have been difficult to realize with a stent having a conventional structure, such as improvement of action and control of drug solution release.

The front view which shows the stent as the 1st Embodiment of this invention. The cross-sectional enlarged view of the strut which comprises the frame | skeleton of the stent shown in FIG. The cross-sectional enlarged view of the strut which comprises the frame | skeleton of the stent as the 2nd Embodiment of this invention. The cross-sectional enlarged view of the strut which comprises the frame | skeleton of the stent as the 3rd Embodiment of this invention. The cross-sectional enlarged view of the strut which comprises the frame | skeleton of the stent as the 4th Embodiment of this invention. It is a front view which shows the stent as the 5th Embodiment of this invention, Comprising: (a) shows a catheter accommodation state, (b) shows an indwelling state. It is a front view which shows the stent as the 6th Embodiment of this invention, Comprising: (a) shows a catheter accommodation state, (b) shows an indwelling state. It is a front view which shows the stent as the 7th Embodiment of this invention, Comprising: (a) shows a catheter accommodation state, (b) shows the state which only the overdeformed area | region expanded, (c) shows an indwelling state. . The front view which shows the stent as the 8th Embodiment of this invention. The front enlarged view which shows the structural example of the chemical | medical agent accommodation recess employable as another aspect of this invention. The cross-sectional enlarged view which shows the structural example of the ultrasonic marker which can be grasped | ascertained also as invention different from this invention. The front view of a cover stent provided with the ultrasonic marker shown in FIG. The perspective view of the stent retriever comprised with the ultrasonic marker shown in FIG. The front view of a catheter provided with the ultrasonic marker shown in FIG. The perspective view of the coil comprised by the ultrasonic marker shown in FIG. The front view which shows the whole shape of the stent as 1 aspect which can be grasped | ascertained as invention different from this invention. The front view which shows the whole shape of the stent as another aspect which can be grasped | ascertained as invention different from this invention. The front view which shows the whole shape of the stent as another aspect which can be grasped | ascertained as invention different from this invention. FIG. 19 is a cross-sectional view showing a specific example of a skeleton that can be used in the stents of FIGS. 16 to 18, and shows a substantially triangular shape (a) and a generally inverted triangular shape (b). FIG. 19 is an explanatory diagram schematically showing the position of a fragile portion that can be employed in the stent of FIGS. FIG. 19 is an explanatory view schematically showing a position of a preferred weak portion in the stent of FIGS. The front view which shows the whole shape in the molding state of the stent as another aspect which can be grasped | ascertained as invention different from this invention. (A) is a perspective view which expands and shows the cross section of the axis orthogonal direction in the stent shown by FIG. 22, (b) is a principal part enlarged view in the axial direction view of (a). Explanatory drawing for demonstrating the magnitude | size of the center angle of the outer peripheral surface and the depression angle of the circumferential direction both sides in sectional drawing of the skeleton shown by FIG.19 (b). Explanatory drawing for demonstrating the principal part of the diameter-reduced state of the stent shown by FIG. (A) is an axial view in the diameter-reduced state of the stent shown by FIG. 25, (b) is explanatory drawing which expands and shows the principal part of (a). The front view which shows the whole shape of the stent as still another aspect which can be grasped | ascertained as invention different from this invention. The front view which shows the whole shape of the stent as another aspect which can be grasped | ascertained as invention different from this invention. It is explanatory drawing which shows the Example of the stent which can be grasped | ascertained as invention different from this invention, Comprising: The figure corresponding to FIG. It is explanatory drawing which shows the comparative example of the stent which can be grasped | ascertained as invention different from this invention, Comprising: The figure corresponding to FIG. It is explanatory drawing for demonstrating the principal part of the diameter-reduced state of the stent shown by FIG. 29, Comprising: The figure corresponding to FIG. FIG. 27 is an explanatory diagram for explaining a main part in a reduced diameter state of the stent shown in FIG. 31 and corresponding to FIG. 26. It is explanatory drawing for demonstrating the principal part of the diameter-reduced state of the stent shown by FIG. 30, Comprising: The figure corresponding to FIG. It is explanatory drawing for demonstrating the principal part of the diameter-reduced state of the stent shown by FIG. 33, Comprising: The figure corresponding to FIG. FIG. 23 is an explanatory diagram for explaining the result of confirming the flow velocity using the stent shown in FIG. 22 which is an embodiment of a stent that can be grasped as an invention different from the present invention, and FIG. The velocity distribution near the wall surface is shown by a vector, and (b) shows the velocity distribution near the blood vessel wall surface by a plane. FIG. 36 is an explanatory view for explaining the result of confirming the flow velocity using the stent shown in FIG. 29 which is another embodiment of the stent which can be grasped as another invention different from the present invention, and corresponds to FIG. To do. It is explanatory drawing for demonstrating the result of having confirmed the flow velocity using the stent shown in FIG. 30 which is a comparative example of the stent which can be grasped as another invention different from the present invention, and corresponds to FIG. Figure. The perspective view which shows the stent as the 9th Embodiment of this invention. FIG. 39 is a cross sectional view showing, in an enlarged manner, main portions of a XXXIX-XXXIX cross section in FIG. 38. FIG. 40 is an enlarged cross-sectional view showing a main part of a stent as a tenth embodiment of the present invention, corresponding to FIG. 39. The top view which shows the stent as the 11th Embodiment of this invention. The top view which shows the 1st frame | skeleton structure which comprises the stent shown by FIG. The top view which shows the 2nd frame structure which comprises the stent shown by FIG. The top view which shows the stent as a 12th Embodiment of this invention. The top view which shows the 1st frame | skeleton structure which comprises the stent shown by FIG. The perspective view which shows the stent as a 13th Embodiment of this invention. The top view which shows another aspect in the stent of this invention. The top view which shows the 1st frame | skeleton structure which comprises the stent shown by FIG. The top view which shows the 2nd frame | skeleton structure which comprises the stent shown by FIG. The perspective view which shows 1 aspect of the stent which can be grasped | ascertained as invention different from this invention. The perspective view which expands and shows the principal part of the stent shown by FIG. The perspective view which expands and shows the principal part of the stent shown by FIG. 50 from another direction. The perspective view which expands the principal part of the stent shown by FIG. 50, and shows it from another direction. The expanded view which cuts open and shows the stent shown by FIG. 50 in 1 part on the circumference. The top view which shows another aspect of the stent which can be grasped | ascertained as invention different from this invention. It is a front view which shows the whole shape in the stent as the 14th Embodiment of this invention, Comprising: (a) is a shaping | molding state, (b) shows the mounting state to a balloon. FIG. 57 is an explanatory view for explaining a balloon linking protrusion in the stent shown in FIG. 56, and is an enlarged view showing a main part in the LVII-LVII cross section in FIG. 56 (b). (B) shows the expanded state of the balloon. It is explanatory drawing for demonstrating the balloon linkage protrusion part in the stent as 15th Embodiment of this invention, Comprising: The figure corresponding to FIG. It is explanatory drawing for demonstrating the balloon linkage protrusion part in the stent as a 16th Embodiment of this invention, Comprising: The figure corresponding to FIG. It is explanatory drawing for demonstrating the balloon linkage protrusion part in the stent as a 17th Embodiment of this invention, Comprising: The figure corresponding to FIG. Explanatory drawing for demonstrating another aspect of the balloon linkage protrusion in the stent of this invention. It is explanatory drawing for demonstrating another aspect of the balloon link | linkage protrusion part in the stent of this invention, Comprising: (a) is a front view which shows the principal part of the stent in the mounting state to a balloon, (b) is FIG. The enlarged view which shows the principal part of the LXII (b) -LXII (b) cross section in (a), (c) is a front view which shows the principal part of the stent in the expansion state of a balloon, (d) is in FIG.62 (c). It is an enlarged view showing a principal part of a cross section of LXII (d) -LXII (d).

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

First, FIG. 1 shows a stent 10 as a first embodiment of the present invention in a molded state before being contracted or expanded. The stent 10 is delivered to a stenotic site of a body lumen such as a blood vessel and is placed in an expanded state at the stenotic site, so that the body lumen is maintained in an expanded state. In the following description, the axial direction refers to the vertical direction in FIG.

More specifically, the stent 10 of the present embodiment is linearly extended in a generally cylindrical shape as a whole, and includes a plurality of annular portions 12 provided at a predetermined distance in the axial direction. . The annular portion 12 is formed to continuously extend in the circumferential direction by repeatedly curving or bending in a wave shape.

Then, the annular portions 12 and 12 adjacent in the axial direction are connected to each other by a link portion 14 extending substantially in the axial direction, whereby the stent 10 having a cylindrical shape with a predetermined length is formed. In the present embodiment, each annular portion 12 and each link portion 14 are integrally connected to constitute a strut 16 as a skeleton. The cylindrical strut 16 can be expanded and contracted in the radial direction of the stent 10. In the present embodiment, each annular portion 12 is folded at both ends in the axial direction, and the folded portions of the annular portions 12, 12 facing each other in the axial direction are connected by the link portion 14. As a result, the strength and the degree of freedom of deformation of the stent 10 are improved, and local deformation such as buckling of the struts 16 during deformation is prevented.

The specific shapes of the annular portion 12 and the link portion 14 are not limited in the present invention, and the wave shape of the annular portion 12 and the connection by the link portion 14 are considered in consideration of the characteristics required for the stent 10. A site | part, the number of the link parts 14 on the periphery of the annular part 12, etc. can be set suitably.

Further, the position of the link portion 14 provided between the annular portions 12 and 12 is not limited in any way, but the link portion 14 is formed in the central portion of the annular portion 12 in the thickness direction (vertical direction in FIG. 2). It is desirable. Furthermore, the link part 14 in this embodiment is located in the center part of the width direction (circumferential direction of the stent 10) of the folded part in the annular part 12, that is, the top part of the folded part in the annular part 12.

Here, the link portion 14 may be a weakened portion having a thickness dimension or a width dimension smaller than that of the annular portion 12. That is, in the skeleton of the stent 10, the cross-sectional area of the link portion 14 can be made smaller than that of the annular portion 12, so that it can be formed as a weakened portion having a partially reduced strength. Then, by forming the fragile portion, the stent 10 may be easily deformed or broken at the fragile portion.

The width and thickness dimensions of the annular portion 12 and the link portion 14 are not particularly limited, but the annular portion 12 has a width and thickness dimension of about 30 to 200 μm for the purpose of ensuring strength. The link portion 14 preferably has a width dimension and a thickness dimension of about 10 to 100 μm.

Further, the strut 16 has a laminated structure as shown in FIG. That is, in the strut 16 of the present embodiment, the core decomposition control layer 20a is laminated on the inner peripheral surface (the lower surface in FIG. 2) of the core layer 18, and the outer peripheral surface (the upper surface in FIG. 2) of the core layer 18. The core decomposition control layer 20b is laminated.

The core layer 18 is formed of a biodegradable material that is decomposed and absorbed in a predetermined period by a living tissue constituting a body lumen, and is formed of a biodegradable resin in this embodiment. The biodegradable resin material forming the core layer 18 is not particularly limited as long as it is a biodegradable material that is decomposed and absorbed by a living body and is a biocompatible material that has a small influence on the living body when placed in the body. However, for example, poly-L-lactic acid (PLLA), polycaprolactone, polyglycolic acid, or a copolymer or composite thereof is suitably employed, and PLLA is employed in this embodiment.

The core decomposition control layer 20 is made of a biodegradable material, and in this embodiment is made of a biodegradable metal. The biodegradable metal material forming the core decomposition control layer 20 is not particularly limited as long as it has both biodegradability and biocompatibility. For example, Mg, Ca, Zn, Li, Fe, or their main components are used. An alloy or the like is preferably employed, and an Mg alloy is employed in the present embodiment. In addition, the Mg alloy which is a material for forming the core decomposition control layer 20 is obtained by adding the above-described biodegradable metal elements (except for Mg) and other biocompatible metal elements to the main component Mg. Has been. In the present embodiment, the core decomposition control layer 20a and the core decomposition control layer 20b are formed of the same material, but the materials for forming the core decomposition control layers 20a and 20b may be different from each other.

The core decomposition control layer 20 a is stacked on the inner peripheral surface of the core layer 18, and the core decomposition control layer 20 b is stacked on the outer peripheral surface of the core layer 18. In the present embodiment, as shown in FIG. 2, core decomposition control layers 20a and 20b are laminated so as to cover substantially the entire surfaces of the core layer 18. The core decomposition control layers 20a and 20b are preferably porous structures having a large number of fine voids penetrating in the thickness direction, whereby the surface of the core layer 18 is microscopically. It is desirable that the core decomposition control layers 20a and 20b are exposed to the outside through gaps.

The stent 10 having the struts 16 having such a laminated structure is produced by integrally forming a plurality of annular portions 12 and link portions 14 each formed of the struts 16 by thermal spraying.

Specifically, the sprayed particles of the material that has been melted or brought close to it by heating are sprayed onto a base material that has been masked corresponding to the peripheral wall structure of the stent 10, so that a large number of the sprayed particles have a predetermined shape. The stent 10 can be formed by solidifying.

In this embodiment, the entire skeleton of the stent 10 is integrally formed, and the laminated structure shown in FIG. 2 is applied not only to the annular portion 12 but also to the link portion 14. However, the laminated structure of the core layer 18 and the core decomposition control layers 20a and 20b as shown in FIG. 2 does not have to be applied to the entire skeleton. For example, several annular portions 12 have such a laminated structure and other structures. The annular portion 12 may have a single layer structure made of one kind of biodegradable material, or the link portion 14 may have a single layer structure.

Further, since the stent 10 of the present embodiment has a laminated structure, it is manufactured through the following processes, for example. That is, first, sprayed particles of Mg alloy are sprayed on the base material, and the inner core decomposition control layer 20a is spray-formed, and then sprayed particles of PLLA are sprayed on the surface of the core decomposition control layer 20a. 18 is formed by thermal spray molding. Finally, sprayed particles of Mg alloy are sprayed on the surface of the core layer 18 to form the outer core decomposition control layer 20b, whereby the stent 10 in which the core decomposition control layers 20a and 20b are laminated on both surfaces of the core layer 18. Is formed.

In addition, in addition to electric spraying such as plasma spraying and arc spraying, spray forming by various known methods such as flame spraying, high-speed flame spraying, and explosion spraying can be employed. Furthermore, cold spray molding is also possible, in which the thermal spray material is plastically deformed into a film or a layer by colliding the thermal spray material with a solid layer at a high speed without being melted or close to the state by heating. Depending on the forming material (spraying material) of the core layer 18 and the core decomposition control layers 20a and 20b to be formed, it can be adopted as one of the spray forming methods of the stent 10.

The stent 10 of the present embodiment having the above-described structure can be expanded and contracted in the radial direction, and is mechanically reduced in diameter from a state before contraction shown in FIG. 1 to a predetermined size. In use, the diameter-reduced stent 10 is delivered to, for example, a stenosis site of a blood vessel by a delivery catheter or the like. Thereafter, the stent 10 is mechanically expanded by a balloon catheter or other mechanical device, or when the stent 10 is formed of a shape memory material, it is automatically expanded by releasing it from the delivery catheter. In the state shown in FIG. 1, it is placed in a body lumen such as a blood vessel.

Further, when the stent 10 according to the present invention is inserted into a lumen such as a blood vessel, the stent 10 is deformed from its initial shape and is delivered by a catheter. In the case where the stent 10 is a balloon expandable type, the balloon 10 is expanded using the balloon so that the stent 10 is placed in a state of being pressed against the inner peripheral surface of the blood vessel. It is automatically expanded when released. It is also possible to have an almost initial shape in such an expanded state. In this case, the shape in the expanded state is stably expressed, and strain and residual stress in the expanded indwelling state are also generated. Effectively suppressed. However, the present invention is not limited to such an embodiment, and can be formed with an initial shape having a diameter different from the shape at the time of indwelling.

In such an indwelling state in the body lumen, the stent 10 formed of the biodegradable material keeps the narrowed portion of the body lumen in the expanded state for a necessary period, and a predetermined period has elapsed. After that, by being decomposed and absorbed by body tissues such as blood vessel walls, the indwelling in the body is eliminated.

Here, in the stent 10, the surface of the core layer 18 is covered with the core decomposition control layers 20a and 20b, and the time required for the decomposition absorption of the core layer 18 is controlled by the core decomposition control layers 20a and 20b. As a result, it is possible to prevent the stent 10 from being decomposed and absorbed too early and the retention period in the expanded state of the body lumen by the stent 10 from being too short, and the decomposition and absorption of the stent 10 to be too late. The risk of causing inflammation and the like can be reduced. Therefore, it is possible to effectively treat a stenosis or occlusion of a blood vessel by stent placement, and it is possible to perform a less invasive stent placement in which restenosis is less likely to occur by accurately controlling the stent placement period.

In this embodiment, the core decomposition control layers 20a and 20b are made of an Mg alloy, and the biodegradation speed of the core decomposition control layers 20a and 20b is made slower than that of the core layer 18 formed of PLLA. Therefore, the core decomposition control layers 20a and 20b covering the surface of the core layer 18 act so as to suppress the decomposition of the core layer 18 in the body for a relatively long period of time, so that the stent 10 is set for a predetermined period. It is easy to adjust the period required for the decomposition so that it is left without being decomposed.

Furthermore, hydrogen ions generated during biodegradation of the core decomposition control layers 20a and 20b formed of Mg alloy are combined with hydroxide ions generated during biodegradation of the core layer 18 formed of PLLA to generate water. This prevents hydrogen ions generated during the decomposition of the core decomposition control layers 20a and 20b from adversely affecting the body tissue, thereby realizing a less invasive stent placement.

The thickness dimensions of the core layer 18 and the core decomposition control layers 20a and 20b and the roughness of the porous core decomposition control layers 20a and 20b are determined according to a predetermined period required for biodegradation of the stent 10. In consideration of the above, it is desirable that the neutralization reaction at the time of biodegradation of the core layer 18 and the core decomposition control layers 20a and 20b is appropriately set. This is because if only one of the core layer 18 and the core decomposition control layers 20a and 20b is decomposed first, the remaining biodegradation reaction may affect the body tissue. As is clear from the above, it is desirable that the combination of the forming materials of the core layer 18 and the core decomposition control layers 20a and 20b is selected so that the influence of the biodegradation reaction on the body tissue is reduced.

Furthermore, since the core decomposition control layers 20a and 20b are made porous, the core layer 18 covered with the core decomposition control layers 20a and 20b is biodegraded at a certain rate by the body tissue. It has become. Thereby, prior to the core layer 18, only the core decomposition control layers 20a and 20b are hardly biodegraded.

As described above, in the stent 10 according to the present invention, the core layer 18 and the core degradation control layers 20a and 20b, each of which is made of a biodegradable material, are laminated to form a multilayer structure, thereby eliminating the narrowing of the body lumen. It is possible to achieve a high degree of avoiding restenosis. However, in the present invention, the material for forming the core layer and the core decomposition control layer and the specific structure of the core layer and the core decomposition control layer are not construed as limited to those of the first embodiment. .

That is, FIG. 3 shows a cross section of the strut 22 constituting the stent according to the second embodiment of the present invention. The struts 22 have the same laminated structure as the struts 16 of the first embodiment. The core disassembly control layer 26a is laminated on the inner peripheral surface of the core layer 24, and the core disassembly control is performed on the outer peripheral surface. The layer 26b is stacked. Also in the present embodiment, both the inner peripheral surface and the outer peripheral surface of the core layer 24 are covered with the core decomposition control layer 26. Further, in the strut 22 of the present embodiment, unlike the strut 16 of the first embodiment, the core layer 24 is formed of an Mg alloy, and the core decomposition control layers 26a and 26b are formed of PLLA.

As described above, the core layer 24 may be formed of a biodegradable metal, and the core decomposition control layers 26a and 26b may be formed of a biodegradable resin. According to this, the core layer 24 which is the main part of the stent is formed of a metal material, so that the stent after placement is more firmly maintained in an expanded shape, and the stenotic site of the body lumen is pushed and expanded. Can be kept stable.

Further, for example, when a drug is supported on a biodegradable resin to have a function as a drug-eluting stent, the core decomposition control layers 26a and 26b, which are outer layers, are formed by a polymer supporting the drug. It is also possible to efficiently release thrombus and prevent inflammation of the blood vessel wall. In order to prevent only the core decomposition control layers 26a and 26b from being decomposed at an early stage, for example, the ratio of the thickness dimension of the core decomposition control layers 26a and 26b to the core layer 24 is set to be higher than that in the first embodiment. It is desirable to enlarge it.

FIG. 4 shows a cross section of a strut 28 constituting a stent as a third embodiment of the present invention. In the strut 28 of the present embodiment, the core layer 30 has a multilayer structure.

That is, the core layer 30 has an inner peripheral metal layer 34a stacked on the inner peripheral surface of the central resin layer 32, an outer peripheral metal layer 34b stacked on the outer peripheral surface, and the inner periphery of the inner peripheral metal layer 34a. The inner peripheral resin layer 36a is laminated on the surface, and the outer peripheral resin layer 36b is laminated on the outer peripheral surface of the outer peripheral metal layer 34b. In other words, the core layer 30 of the present embodiment is a multilayer structure in which three resin layers formed of PLLA and two metal layers formed of Mg alloy are alternately stacked. Yes. In addition, the number of layers and the forming material of the core layer 30 having a multilayer structure are merely examples, and are not particularly limited.

Further, core decomposition control layers 20a and 20b formed of a biodegradable material are laminated on both surfaces of the core layer 30 as in the first embodiment, and the core decomposition control layer 20a is an inner peripheral resin layer. While being fixed to the inner peripheral surface of 36a, the core decomposition control layer 20b is fixed to the outer peripheral surface of the outer peripheral resin layer 36b. In short, the strut 28 of the present embodiment has a seven-layer structure in which one core decomposition control layer 20a, 20b is fixed to both surfaces of a five-layer core layer 30, and is formed of an Mg alloy. Metal layers and resin layers formed of PLLA are alternately stacked.

In this embodiment, all the resin layers 32, 36a, and 36b are formed of PLLA, and all the metal layers 20a, 20b, 34a, and 34b are formed of Mg alloy. Different resin materials may be used, and each metal layer may be formed of different metal materials.

According to the stent having the core layer 30 having such a multilayer structure, since the core layer 30 has a multilayer structure having a metal layer, the entire core layer, which is the main portion of the stent, is formed of resin. Compared to the case, the stability of the shape is excellent, and recoil is easily suppressed.

In addition, when a relatively thin metal layer is provided dispersed in the core layer 30 and the core decomposition control layers 20a and 20b, both surfaces of the strut 28 are covered with thick metal core decomposition control layers 20a and 20b. In comparison, excessive suppression of biodegradation of the core layer 30 can also be avoided. In addition, since both surfaces of the strut 28 are covered with the metal core decomposition control layers 20a and 20b, it is easy to prevent the biodegradation rate of the core layer 30 from becoming too fast.

Thus, according to the stent of this embodiment provided with the struts 28, the biodegradation rate in the stent 10 of the first embodiment can be easily controlled, and the stent in the second embodiment is excellent in the indwelling state. Shape stability can be realized at the same time.

Further, like the strut 38 shown in FIG. 5, a contrast layer 40 may be further provided on the strut 28 of the third embodiment.

That is, FIG. 5 shows a cross section of a strut 38 constituting a stent according to a fourth embodiment of the present invention. The core decomposition control layers 20a and 20b and inner peripheral metal layer 34a made of metal and The contrast layer 40 is laminated on each surface of the outer peripheral metal layer 34b. The contrast layer 40 is formed of a biocompatible radiopaque material, and a thin film such as Au, Pt, or tantalum can be suitably used. In the present embodiment, the core layer 30 is configured to include four contrast layers 40, 40, 40, 40 laminated on both surfaces of the inner metal layer 34a and both surfaces of the outer metal layer 34b. In addition to the core decomposition control layers 20a and 20b, the core decomposition control layer includes four contrast layers 40, 40, 40, and 40 stacked on both surfaces thereof. The inner and outer core disassembly control layers also have a multilayer structure.

The contrast layer 40 is not necessarily required to cover the entire surfaces of the core decomposition control layers 20a and 20b and the metal layers 34a and 34b, and may be partially laminated. Further, in this embodiment, the contrast layer 40 is laminated on both surfaces of the core decomposition control layers 20a and 20b and the metal layers 34a and 34b, but the core decomposition control layers 20a and 20b and the metal layers 34a and 34b are stacked. It may be selectively laminated on only one or several, or may be laminated only on one of the surfaces of the core decomposition control layers 20a and 20b and the metal layers 34a and 34b.

By providing such a contrast layer 40, it becomes easy to confirm the position of the stent in stent placement under fluoroscopy. In addition, since the contrast layer 40 is formed into a plurality of thin layers arranged apart from each other, particularly excellent visibility is exhibited in the overlapping portion of the contrast layers 40 under X-ray fluoroscopy.

Further, if the contrast layer 40 is formed of a material that does not have biodegradability such as Au or Pt, the decomposition rate of each of the core layer 30 and the core decomposition control layers 20a and 20b formed of the biodegradable material is It can also be adjusted by the contrast layer 40. Furthermore, since the contrast layer 40 remains in the body tissue even after all the portions of the stent formed of the biodegradable material are decomposed and absorbed, the contrast layer 40 remaining in the body tissue can be confirmed by fluoroscopy. For example, it is possible to grasp the site where the stent is placed in the blood vessel even after the stent body is decomposed and absorbed. The contrast layer 40 has excellent biocompatibility and is formed of Au or Pt, which is a stable material, and is sufficiently thin, so restenosis or the like does not pose a problem.

By the way, when a stent is placed at a stenosis site in a body lumen as described above, it is desirable that the stent shape after placement is highly compatible with the shape of the stenosis site in the body lumen. Accordingly, FIGS. 6 to 9 show other embodiments of stents 50, 60, 62, and 68 in which the shape after placement can be highly adapted to the shape of the stenosis site in the body lumen. Has been.

That is, FIG. 6 shows a stent 50 as a fifth embodiment of the present invention. The stent 50 has a cylindrical shape that extends substantially linearly before placement, and, like the stent 10 of the first embodiment, a plurality of annular portions 52 are arranged side by side in the axial direction, and the shaft 50 By connecting the annular portions 52 and 52 adjacent to each other in the direction by the link portion 54, a cylindrical skeleton is formed. In the following description, members and portions that are substantially the same as those in the first to fourth embodiments are denoted by the same reference numerals in the drawings, and the description thereof is omitted. In FIG. 6, (a) shows the stent 50 housed in the delivery catheter in a reduced diameter state, and (b) shows the stent 50 placed in the body lumen.

Further, the stent 50 has a plurality of self-expanding regions 56 and a plurality of overdeformed regions 58. In the present embodiment, five self-expanding regions 56 arranged in the axial direction are provided, and overdeformation regions 58 are provided between the self-expanding regions 56 in the axial direction.

The self-expanding region 56 is formed of a metal material having a shape memory effect, and is released from a delivery catheter accommodated in a reduced diameter state, so that the self-expanding region 56 is automatically shaped in advance by superelasticity (during molding). The shape is restored and expanded. Each self-expanding region 56 includes two annular portions 52a and 52a that are adjacent in the axial direction, and a plurality of link portions 54a that connect them, and the annular portions 52a and 52a and a plurality of links. The portion 54a is integrally formed of a shape memory material. The material for forming the self-expanding region 56 is not particularly limited as long as it is a biocompatible superelastic material. For example, various alloys such as a NiTi alloy are preferably used.

The over-deformation region 58 is provided in a portion that is off the self-expanding region 56 in the axial direction, is formed of a metal material that does not have a shape memory effect, and is released from a delivery catheter accommodated in a reduced diameter state. After that, it can be mechanically expanded by a balloon or the like. Further, the excessive deformation region 58 can be deformed to be larger than the self-expanding region 56 by adjusting the force exerted by the balloon or the like. It can be extended in the axial direction larger than the expansion region 56.

The material for forming the over-deformed region 58 is not particularly limited as long as it is a biocompatible material and can be easily deformed by a balloon or the like. For example, stainless steel (SUS316L), CrCo alloy, tantalum Etc. can be suitably employed. Each over-deformed region 58 includes two annular portions 52b and 52b adjacent in the axial direction and a link portion 54b that connects them, and the annular portions 52b and 52b and the link portion 54b are described above. It is formed with the following materials. The annular portion 52a and the annular portion 52b have substantially the same shape in the molded state and have different forming materials, and the annular portion 52 includes two types of annular portions 52a and 52b that are different in forming material. Has been. Similarly, the link portion 54a and the link portion 54b are also formed of different forming materials having substantially the same shape, and the link portion 54 is composed of two types of link portions 54a and link portions 54b having different forming materials.

Further, the self-expanding region 56 and the hyperdeformed region 58 may be covered with a thin layer such as radiopaque Au, Pt, or Ta so that the visibility of the stent 50 can be seen under fluoroscopy. Is improved. In addition, since the stent 50 of the present embodiment expands into a bent shape so as to correspond to the bent blood vessel, the bending direction in the expanded state of the stent 50 can be grasped under fluoroscopy. For example, it is desirable to provide an X-ray marker indicating the bent inner peripheral side.

Then, the stent 50 is formed by providing the self-expanding regions 56 and the excessively deforming regions 58 alternately and continuously in the axial direction. That is, both end portions in the axial direction of the stent 50 are self-expanding regions 56, and overdeformation regions 58, 58, 58, 58 and self-expanding regions 56 are formed inside the self-expanding regions 56, 56 constituting the both end portions. , 56, 56 are alternately arranged. The self-expanding region 56 and the overdeformed region 58 of this embodiment are integrally formed by means such as spraying, vacuum deposition, etching, electroforming, etc., but are fixed to each other by welding after being formed separately. May be.

The stent 50 having such a structure is accommodated in a delivery catheter in a reduced diameter state shown in FIG. 6A, and is carried to a stenotic site of a body lumen by the delivery catheter, and then from the delivery catheter. It is released and placed at the stenosis site in the body lumen.

In addition, the stent 50 of the present embodiment is applied when the stenosis portion of the body lumen is curved or bent, and as shown in FIG. 6B, the bent or bent corresponding to the body lumen. Detained in shape. That is, when the stent 50 is placed in a curved or bent stenosis site, the self-expanding region 56 is automatically expanded by superelasticity and pressed against the inner wall of the body lumen, and the The deformation or bending of the stent 50 is adjusted according to the shape of the body lumen. Further, the hyperdeformed region 58 is allowed to deform larger than the self-expanding region 56 and can be shaped by a balloon or the like after releasing the stent 50 from the delivery catheter. Therefore, by appropriately deforming the over-deformed region 58, the shape of the stent 50 can be adjusted after the expansion deformation of the self-expanding region 56 to be more adapted to the shape of the body lumen. FIG. 6B shows an example in which the left part of the over-deformed region 58 in the figure is deformed to be larger than the right part in the figure so that the curved shape is inclined to the right in the figure as it goes to both ends in the axial direction. However, the deformation | transformation aspect of the overdeformation area | region 58 is not limited to this. Note that the stent 50 of the present embodiment that expands into a curved or bent shape is particularly effective for highly curved or bent portions of, for example, a blood vessel of a patient who has advanced arteriosclerosis.

In addition, when the stenosis part of the body lumen is hard enough not to be expanded in the self-expanding region 56, the stenosis part can be expanded by balloon expansion of the hyperdeformation region 58. When the stenosis part is pushed and expanded by balloon expansion of the over-deformation region 58, if the restriction by the stenosis part is released and the self-expansion area 56 is expanded, the stenosis part is supported by the self-expansion area 56 and stenosis by recoil is performed. Is avoided. The over-deformed region 58 that is covered and formed of SUS is relatively easily deformed by the action of an external force, as is understood from allowing expansion by a balloon, but the self-formed region formed of NiTi alloy. This is because the expansion region 56 exhibits expansion deformation due to transformation from the martensite phase to the parent phase, and exhibits high deformation rigidity after expansion.

FIG. 7 shows a stent 60 as a sixth embodiment of the present invention. The stent 60 has a linear cylindrical shape as a whole, and has an intermediate portion as a self-expanding region 56 and both end portions as an overdeformed region 58. In FIG. 7, (a) shows the stent 60 housed in the delivery catheter in a reduced diameter state, and (b) shows the stent 60 in a state of being placed in the body lumen. .

In the state in which the stent 60 is housed in the delivery catheter, both the self-expanding region 56 and the over-deformed region 58 are reduced in diameter, and as shown in FIG. It has a constant outer diameter.

Then, the stent 60 carried to the stenosis portion of the body lumen by the delivery catheter is placed in an expanded state as shown in FIG. That is, in the stent 60 released from the delivery catheter, the self-expanding region 56 automatically expands and deforms to expand the wall portion of the stenosis site, and the over-deformation regions 58 at both ends have the expanded self-expanding region. The diameter is expanded and deformed by a balloon so as to have a larger diameter than 56. In FIG. 7 (b), the overdeformed region 58 is deformed into a tapered shape having a diameter that increases outward in the axial direction, and both ends of the overdeformed region 58 are stabilized against the inner wall of the body lumen. To be pressed.

According to this, since both ends of the stent 60 are easily brought into close contact with the inner wall of the body lumen, thrombus formation due to blood flow disturbance at both ends is reduced or avoided, and restenosis or the like is performed. Can be avoided. In particular, since both ends of the stent 60 are constituted by the hyperdeformed region 58 and can be deformed later by a balloon in accordance with the shape of the body lumen, the stent 60 is securely attached to the blood vessel wall or the like. While being able to indwell in a more stable state, the formation of thrombus can be suppressed.

FIG. 8 shows a stent 62 as a seventh embodiment of the present invention. The stent 62 has a structure in which a hyperdeformed region 58 is provided at the distal end (lower end in FIG. 8) of the self-expanding region 56. FIG. 8A shows a state where the stent 62 is accommodated in the delivery catheter 64. (B) shows a state in which the self-expanding region 56 of the stent 62 is accommodated in the delivery catheter 64 and the over-deformed region 58 is released from the delivery catheter 64. (C) shows an indwelling state in which the stent 62 is released from the delivery catheter 64.

Then, as shown in FIG. 8A, the stent 62 accommodated in the delivery catheter 64 is transported to the stenosis part of the body lumen, and then, as shown in FIG. While housed in the delivery catheter 64, the distal end hyperdeformed region 58 is released from the delivery catheter 64 and is expanded by the balloon catheter 66. As a result, the hyperdeformed region 58 is pressed against the inner wall surface of the body lumen, and the stent 62 is positioned with respect to the body lumen. Note that the delivery catheter 64 and the balloon catheter 66 are not requirements for configuring the present invention, but are shown in FIGS. 8A and 8B for the purpose of facilitating understanding.

Next, as shown in FIG. 8 (c), the self-expanding region 56 is released from the delivery catheter 64 and is pressed against the constriction portion of the body lumen by self-expansion based on superelasticity. It is expanded by the stent 62.

In a general self-expanding stent, when the proximal end of the stent is released from the delivery catheter, a distal force acts on the stent, and the placement position may be shifted due to jumping. Here, since the stent 62 of the present embodiment is positioned with respect to the body lumen by the pre-expanded hyperdeformed region 58, jumping can be prevented from occurring when the self-expanding region 56 is released.

FIG. 9 shows a stent 68 as an eighth embodiment of the present invention. The stent 68 has a self-expanding region 56 at both ends in the axial direction and an over-deformed region 58 at the intermediate portion.

Then, in the indwelling state in the body lumen shown in FIG. 9, the stent 68 has a tubular skeleton formed by a part of the wall portion of the skeleton constituting the over-deformed region 58 being expanded by a balloon or the like. A branch opening 69 that opens to the side is formed in a part of the wall. More specifically, in the stent 68 of the present embodiment, a balloon is inserted between the axial directions of the adjacent annular portions 52a and 52b, and the gap between the annular portions 52a and 52b is expanded by the balloon. The over-deformed region 58 is deformed larger than the self-expanding region 56 to form a branch opening 69 that penetrates the peripheral wall portion of the skeleton.

As described above, if the branch opening 69 can be formed in the peripheral wall portion of the skeleton by deformation of the over-deformed region 58, the stent 68 according to the present invention can be suitably used as a stent to be placed in the branch portion of the blood vessel. In addition, since the branch opening 69 is formed by the post-deformation of the hyperdeformed region 58 by the balloon in a state where the stent 68 is positioned with respect to the body lumen by the deformation of the self-expanding region 56, The shape can be more accurately matched to the branch portion of the blood vessel. It should be noted that another stent can be inserted into the branch vessel through the branch opening 69 after the stent 68 is placed.

In the present embodiment, an example in which the branch opening 69 is formed between the axial directions of the adjacent annular portions 52a and 52b has been shown. However, for example, the branch opening 69 is formed between the axial directions of the adjacent annular portions 52b and 52b. It can also be formed. Further, the branch opening 69 may be formed by deforming the annular portion 52b so as to expand in the axial direction, or the branch opening 69 can be formed by expanding the annular portion 52b in the circumferential direction.

Although the embodiments and examples of the present invention have been described in detail above, the present invention is not limited to the specific descriptions, and various changes, modifications, improvements, and the like have been added based on the knowledge of those skilled in the art. Any embodiment may be implemented within the scope of the present invention without departing from the spirit of the present invention.

For example, in the first to fourth embodiments, the structure is not limited to the structure in which the core decomposition control layers 20 and 26 are laminated on the entire surface of the core layers 18, 24 and 30. It may be partially provided on the surface of the core layers 18, 24, 30. The core decomposition control layers 20 and 26 may be formed only on the surface of any one of the core layers 18, 24 and 30.

Further, for example, in the stent 10 of the first embodiment, the core layer 18 is formed of a biodegradable metal, or the core decomposition control layers 20a and 20b are formed of a biodegradable resin. It may be formed of a degradable resin or a biodegradable metal. The core layer and the core decomposition control layer may be formed of the same material, but are preferably formed of different materials. For example, even when both the core layer and the core decomposition control layer are formed of an Mg alloy, the core layer and the core are made different by changing the kind of metal element added to Mg, which is the main component, and the proportion of the metal element. It is desirable to impart suitable characteristics to the decomposition control layer.

Further, when the core layer and the core decomposition control layer have a laminated structure like the core layer 30 of the third and fourth embodiments, the production as in the third and fourth embodiments is performed. The structure is not limited to a structure in which a degradable resin layer and a biodegradable metal layer are alternately arranged, and a multi-layer core layer (core decomposition control layer) may be formed of a plurality of types of biodegradable resin layers. Further, it may be composed of a plurality of types of biodegradable metal layers. Note that both the core layer and the core decomposition control layer may have a multilayer structure.

Further, in the structure of the first and second embodiments having the core layers 18 and 24 having a single layer structure, the contrast layer 40 as in the fourth embodiment may be provided. The contrast layer 40 may be formed of a single material having excellent contrast properties such as Au and Pt. For example, the contrast material is mixed with the biodegradable material substantially uniformly and sprayed (co-spray). Thus, the core layers 18 and 24 and the core decomposition control layers 20 and 26 can also be formed so as to serve as a contrast layer.

Further, in the stent having the self-expanding region 56 and the over-deformed region 58 as in the fifth to eighth embodiments, the self-expanding region 56 and the over-deformed region 58 are arranged at different positions in the axial direction. For example, their arrangement can be changed as appropriate.

For example, an appropriate shape such as embossing may be attached to the surface of the stent, and when the stent is produced by thermal spraying, by appropriately setting the shape of the base material or mask used for thermal spraying. An appropriate shape such as embossing can be easily formed on the surface. Thus, by providing unevenness on the outer peripheral surface of the stent, for example, it can be effectively used as a drug-eluting stent. That is, for example, by applying or depositing a drug that suppresses cell growth or a resin layer containing such a drug on the outer peripheral surface of a stent with irregularities, the drug can be eluted from the blood vessel wall. it can. At that time, the wettability is improved by such unevenness, and the applied drug or the resin layer can be easily attached to the outer peripheral surface of the stent and can be made difficult to peel off.

Further, as shown in FIG. 10, for example, a medicine containing recess 70 for containing medicine may be formed in the skeleton of the stent, that is, the annular portion 12 and the link portion 14. Specifically, when the stent is formed by thermal spraying or electroforming, for example, by treating the surface of the molding base (base material) with a protrusion or the like, the inner surface of the stent formed on the surface is processed. A recess having a size corresponding to the peripheral surface can be transferred and formed. Further, by forming an island-shaped mask on the central portion of the surface of the skeleton formed in advance and performing thermal spraying or electroforming, a peripheral wall surrounding the island-shaped mask portion is formed, and the central mask portion It is also possible to form a recess opening in the outer peripheral surface of the stent. Such a medicine receiving recess 70 can be formed in any shape and size, and other than the groove shape extending in the length direction of the annular portion 12 and the link portion 14 as shown in FIG. It may be a hole such as a circle. When such a stent is produced by thermal spraying or electroforming, it is possible to form a recess of any size on the surface by appropriately setting the shape of the molding base and mask used, The degree of freedom of design can be greatly secured.

Further, when the stent is formed by electroforming, for example, using a eutectoid plating technique using an electrolytic solution in which a non-conductive powder is dispersed, a porous structure or microporous corresponding to the eutectoid fine particles is used. It is also possible to give the structure to the annular part 12 and the link part 14.

Thus, by forming the annular portion 12 and the link portion 14 with the drug containing recess 70 and the porous structure, the amount of metal constituting the stent can be reduced. In addition, by loading the drug in the drug containing recess 70 or the porous structure, for example, a drug-eluting stent as described above can be formed, and the drug can be effectively eluted into the blood vessel wall.

Furthermore, the drug containing recess 70 formed in the stent may be not only a bottomed shape but also a through hole. By forming the through hole in the stent in this way, the loading of the drug can be further facilitated and the amount of the drug loaded can be increased. In addition, since the through-hole becomes hollow after the drug or the like is eluted, blood can pass through the through-hole. For example, blood flow is inhibited as compared with the case where the recess is bottomed. Therefore, the effect of preventing turbulent flow and restenosis can be exhibited.

Further, the medicine may be directly placed in the medicine housing recess 70, for example, a biodegradable resin cotton impregnated with the medicine or a capsule filled with the medicine is placed in the medicine housing recess 70. Also good.

Furthermore, the unevenness formed on the stent may be formed directly on the surface of the stent. For example, by forming a convex portion on the surface of the stent, a relatively concave portion is formed. May be.

Further, the stent 10 may be provided with an ultrasonic marker 72 as shown in FIG. The ultrasonic marker 72 is made of resin or metal, and has a large number of minute voids 74 therein. The minute voids 74 contain a gas such as air. And the ultrasonic marker 72 is excellent under the fluoroscopic perspective because the irradiated ultrasonic wave is reflected at the boundary between the solid part formed of resin or metal and the gas phase of the minute gap 74. Visibility is demonstrated.

The microscopic voids 74 of the ultrasonic marker 72 may have a porous structure that is continuous to some extent, but it is desirable that the microscopic voids 74 be made of a liquid such as blood. It becomes difficult to satisfy, and high visibility under ultrasonic fluoroscopy can be maintained for a long time. However, the minute gap 74 does not necessarily need to be filled with gas, and may be filled with a liquid, or an individual made of a material different from the solid portion may be accommodated.

The ultrasonic marker 72 is formed by thermal spray molding, for example. In other words, the spraying density of spray particles is set to be small during spray forming, a relatively large number of pores and a coarse spray coating is formed. The ultrasonic marker 72 having the minute gap 74 can be easily formed. In particular, in the case of thermal spray molding, it is possible to select a molding material from a wide range of resin materials and metal materials, and a molding material that takes into account the required characteristics such as biodegradability and biocompatibility can be selected with great flexibility. can do. However, the method of forming the ultrasonic marker 72 is not limited to thermal spraying, and can be formed by etching in addition to vacuum deposition and electroforming, which are the same film formation techniques as thermal spraying.

The ultrasonic marker 72 having such a structure is applied to, for example, a stent as shown in FIGS. That is, FIG. 12 shows a covered stent 76 used as a flow diverter or a stent graft. The covered stent 76 has a structure in which a stent main body 80 composed of a plurality of annular portions 78 arranged away from each other in the axial direction is fixed to the outer peripheral surface of a cylindrical cover 82 formed of a resin thin film such as PTFE. Has been. As shown in the embodiment, the annular portion 78 has a shape that extends in the circumferential direction while undulating in the axial direction, and has at least one of self-expandability by superelasticity and mechanical expandability using a balloon stent or the like. I have.

And the ultrasonic marker 72 of this embodiment is integrally fixed to the surface of the stent body 80 or the surface of the cover 82, for example. This improves the visibility of the covered stent 76 under ultrasonic fluoroscopy, and makes it easier to grasp the position of the covered stent 76 in the stent placement under echo.

Also, the ultrasonic marker 72 can be applied to a stent that does not have the cover 82, such as the stent retriever 84 shown in FIG. The stent retriever 84 is a cylindrical mesh-type stent-type thrombectomy device, for example, for pressing and removing a thrombus with a net to remove it. Further, in the stent retriever 84, the entire skeleton has a structure including the minute gap 74, and the skeleton itself is the ultrasonic marker 72. Thus, the ultrasonic marker 72 is not limited to the one provided on the surface of the stent, and for example, the entire skeleton of the stent may be the ultrasonic marker 72. Furthermore, in the case where the skeleton of the stent itself is the ultrasonic marker 72, the microvoids 74 are continuously penetrating into the surface so that the blood contact area with the blood vessel wall becomes large and less invasive. In addition, the indwelling position can be stabilized by fine surface roughening.

Note that the ultrasonic marker 72 as described above is not necessarily applied only in an aspect combined with the present invention, and can be applied to, for example, a medical device other than a stent. Specifically, the present invention can be applied to a catheter 86 as shown in FIG. 14, a coil 88 for stagnating the blood flow of an aneurysm as shown in FIG. 15, a guide wire used for introducing a catheter, and the like. The ultrasonic marker 72 is improved in visibility even when the position is confirmed using, for example, IVUS (intravascular ultrasound), and the position is easily grasped. As understood from this, the invention relating to the ultrasonic marker 72 can also be recognized as an independent invention that can solve a different problem from the present invention.

That is, the first aspect of the present invention is a medical device to be inserted into a body lumen, comprising an ultrasonic marker formed of a sparsely structured structure having a minute gap inside, and the ultrasonic marker. Is formed by at least one of thermal spraying, vapor deposition, etching, and electroforming.

The second aspect is the medical device according to the first aspect, wherein at least one of a catheter, a stent, a coil, and a thrombus collection device provided with the ultrasonic marker is used.

A third aspect is a stent having a cylindrical skeleton that can be expanded and contracted in the medical device according to the first or second aspect, wherein the skeleton is the ultrasonic marker.

In addition, the shape of the stent is not limited to a simple straight shape as illustrated in the above embodiment or a shape in which a thick portion is provided at an end or center in the length direction, but a tapered cylindrical shape, Thick end shape, Y-shaped branch shape including a main cylinder portion and a branch cylinder portion, a shape in which the diameter of the main cylinder portion and the branch cylinder portion are different in the Y-shaped branch shape, The present invention is applicable to various types of irregularly shaped stents, such as at least one having a tapered cylindrical shape and a shape partially tapered in the length direction.

Furthermore, the rigidity of both end portions in the axial direction of the stent may be increased by making the both end portions in the axial direction of the stent thick or adopting a metal having high rigidity as both end portions in the axial direction. According to this, lifting from the blood vessel at both axial end portions of the stent is suppressed, and the stent is stably placed at the stenosis site of the blood vessel. In particular, since the lift from the blood vessel is suppressed at both axial ends of the stent, the risk of thrombus formation due to blood flow disturbance is reduced, and restenosis can be effectively prevented.

Furthermore, the cross-sectional shapes of the annular portion 12 and the link portion 14 may be different in the skeleton of the stent 10. However, in the stent of the present invention, the link portion is not essential, and the annular portions adjacent in the axial direction of the stent may be continuously connected in a spiral structure. In this case, there is no need to provide a link portion, and the skeleton of the stent can be formed without the link portion. Furthermore, it is also possible to adopt a skeleton having a mesh structure as a whole by a plurality of struts extending in a spiral shape opposite to each other. Further, when the stent having the self-expanding region 56 and the over-deformed region 58 as shown in the fifth to eighth embodiments is formed in a structure in which the struts are spirally continuous, the struts in the length direction To form a stent with a self-expanding region 56 partially in the axial direction.

Furthermore, the thickness dimension and cross-sectional shape of the strut need not be uniform over the entire length. For example, it may be partially thick or thin in the length direction of the strut. Moreover, when not providing a link part as mentioned above, a weak part may be formed of the thin part of the strut.

Furthermore, a stent having a structure according to the present invention may be formed by electroforming or vacuum deposition known as a molding technique such as film formation as well as thermal spraying. For example, a molded base is immersed in an electrolytic bath in which a predetermined metal is ionized to form a stent by electrodepositing metal ions and integrating them into a predetermined shape, or particles of a material that is vaporized or sublimated by heating. It is also possible to form a stent by integrating a large number of these into a predetermined shape. Even when the stent is formed by electroforming or vacuum deposition, it can be easily manufactured by appropriately masking the surface of the molding base. It is also possible to form a stent with a predetermined shape by etching. That is, a stent can be formed by removing unnecessary portions of a cylindrical body made of a predetermined material with a chemical solution or an active group by gas discharge.

16 to 28 show stents 90, 104, 106, 108, 110, and 112 that can be recognized as independent inventions that can solve problems different from the present invention. These stents 90, 104, 106, 108, 110, 112 are formed by, for example, the above-described spraying, vapor deposition, etching, electroforming, or the like.

The stent 90 shown in FIG. 16 includes a substantially cylindrical shape and a trunk cylinder portion 92 and a branch cylinder portion 96 that extend linearly, and a branch portion provided at an intermediate portion in the length direction of the trunk cylinder portion 92. As a whole, the branch cylinder portion 96 is inclined to the side from 94 and extends to have a substantially Y-shaped branch shape. In other words, in the stent 90 of the present embodiment, the number of tube portions is different in the length direction (vertical direction in FIG. 16) by the branch portion 94, that is, the stent 90 has a cross-sectional shape in the length direction. It is an irregularly shaped cylinder shape that changes.

Each of the trunk tube portion 92 and the branch tube portion 96 is provided with a plurality of annular portions 98 that are continuously curved in the circumferential direction and repeatedly bent or bent in a wavy shape with a predetermined distance from each other in the axial direction. As a result, a series of struts 102a constituting the trunk cylinder portion 92 and a series of struts 102b constituting the branch cylinder portion 96 are formed. And the annular parts 98 and 98 adjacent to each other in the axial direction in the struts 102a and 102b are respectively connected by the link parts 100 extending in the substantially axial direction, thereby forming a cylindrical shape having a predetermined length.

In particular, in the present embodiment, in the branch portion, the annular portion 98 that constitutes the basic cylinder portion 92 and the annular portion 98 that constitutes the branch cylinder portion 96 are continuous on the circumference of the basic cylinder portion 92 and the branch cylinder portion 96. It extends. Thereby, the integral structure of each strut 102a, 102b is implement | achieved in the branch part of the basic cylinder part 92 and the branch cylinder part 96, and the continuous strut 102 is comprised. In the strut 102, the skeleton of the stent 90 of the present embodiment is configured by connecting the annular portions 98 and 98 adjacent in the axial direction by the link portion 100. As a result, the strength and the degree of freedom of deformation of the stent 90 are improved, and local deformation such as buckling of the strut 102 during deformation is prevented.

The specific shapes of the annular portion 98 and the link portion 100 are not limited in the present invention, and the wave shape of the annular portion 98 and the connection by the link portion 100 are considered in consideration of the characteristics required for the stent 90. A part, the number of the link parts 100 on the periphery of the annular part 98, etc. can be set suitably.

Further, the width dimension and the thickness dimension of the annular portion 98 and the link portion 100 are not particularly limited, but the strut 102 constituting the annular portion 98 is about 30 to 200 μm for the purpose of ensuring the strength. The width dimension and the thickness dimension are desirable, and the link portion 100 is desirably a width dimension and a thickness dimension of about 10 to 100 μm.

And such a branched stent 90 is produced by integrally forming a plurality of annular portions 98 and link portions 100 constituting the strut 102 by electroforming.

Specifically, a molding base having the shapes and sizes of the target basic cylinder portion 92 and the branch cylinder portion 96 is prepared by using a conductor such as stainless steel. Then, on the surface of the molding base, an exposed surface is formed in a shape corresponding to each of the plurality of annular portions 98 and the link portions 100, and a non-conductive mask is applied to other regions. Then, it is immersed in an electrolytic bath in which a predetermined metal is ionized, and metal ions are electrodeposited on the exposed surface of the molding base to perform electroforming. After obtaining a metal having a predetermined thickness, the mask 90 is removed, and the molded base is extracted or dissolved to obtain the stent 90 having the above-described target structure.

The stent 90 of this embodiment having the above-described structure is capable of expanding and contracting in the radial direction in the trunk cylinder portion 92 and the branch cylinder portion 96, and has a predetermined dimension from the state before contraction shown in FIG. The diameter is reduced mechanically. In use, the stent 90 is delivered to, for example, a stenosis site of a blood vessel by a delivery catheter or the like. Thereafter, the stent 90 is expanded by a balloon catheter, or when the stent 90 is formed of a shape memory material, the stent 90 is automatically expanded by being released from the delivery catheter, and in the state shown in FIG. Etc. are placed in the body lumen.

Since the stent 90 of this embodiment is manufactured by electroforming, a branched shape having a trunk cylinder portion 92 and a branch cylinder portion 96 can be integrally formed. Therefore, compared to the case where two stents obtained by laser processing straight cylindrical metal fittings as in the conventional structure are joined to form a branched shape, the portion to be excised can be reduced, The yield can be improved and a complicated branch shape can be obtained with high accuracy. Therefore, it is possible to realize the stent 90 with high yield with respect to a complicated shape part such as a blood vessel of a living body with high accuracy.

In addition, since it is manufactured by electroforming as described above, the degree of freedom in design of the shape is greatly improved while ensuring the integral formability of the stent 90. Compared to the obtained stent, it is possible to obtain a stent with various irregular initial shapes.

For example, as shown in FIG. 17, the stent 104 as another embodiment having a tapered cylindrical shape whose inner and outer diameter dimensions change in the axial direction is also integrally formed by electroforming with an initial shape of a target taper angle. Can do. The stent 104 of the present embodiment has such a tapered shape and a deformed cylindrical shape whose cross-sectional shape changes in the length direction. In the following description, the same members and parts as those in the above-described aspect are denoted by the same reference numerals as those in the above-described aspect, and detailed description thereof is omitted.

Since such a stent 104 is tapered in an initial shape when placed in a blood vessel or the like whose diameter is changed, distortion and residual stress in the placed state can be suppressed.

Further, since the skeletons of the stents 90 and 104 as described above, that is, the struts 102 and the link part 100 are manufactured by electroforming, it is possible to have a laminated structure of different materials. Specifically, after forming a non-conductive mask on the surface of the molding base as described above and performing the first electroforming, the electroforming is performed in the second electrolytic bath of another metal ion. By performing the casting, a metal layer of another material can be formed on the surface of the metal formed by the first electroforming by the second electroforming. As can be seen from this, the invention of this aspect can be adopted in combination with the inventions according to the first to fourth embodiments. Similarly, the invention of this aspect can be adopted in combination with the inventions according to the fifth to eighth embodiments.

Such a laminated structure of metals can be performed any number of times, for example, a structure in which a surface layer portion is provided by coating another metal so as to cover a core portion formed of a specific metal is also possible. It is. In that case, for example, it is preferable that the metal of the surface layer portion has a higher ductility than the metal of the core portion. As a result, the followability when the stent is bent is improved, and the concentration of strain and stress in the surface layer portion is avoided.

Further, it is preferable that the metal in the surface layer portion has a smaller ionization tendency than the metal in the core portion. Specifically, for example, the core portion is formed of stainless steel (SUS316L), CrCo alloy, tantalum, NiTi, etc., while the surface layer portion is Ni, NiCo, Cu, NiW, Pt, Au, Ag, Cr, Zn, etc. Preferably, it can be formed of Au or Pt. Accordingly, it is possible to improve biocompatibility by suppressing the potential difference from the living body with the metal in the surface layer portion while efficiently ensuring strength and rigidity with the metal constituting the core member. Moreover, since the ionization tendency of Au, Pt, etc. is very low, metal elution can be suppressed. Furthermore, elution of metal ions that cause metal allergy such as Ni used in the alloy as the core material can be suppressed. Moreover, since Au, Pt, etc. have a large specific gravity and good radiopacity, the visibility of a stent using X-rays can be improved.

In addition, after performing the first electroforming, it is also possible to re-form the mask and perform the second electroforming. Accordingly, for example, the annular portion 98 and the link portion 100 can be formed of different metal materials, and the material of the annular portion 98 can be partially different in the length direction and the circumferential direction of the stent 90. become.

Specifically, as still another aspect, as shown in FIG. 18, in the straight cylindrical stent 106, only one or a plurality of annular portions 98 positioned at the axial ends thereof are provided. The thickness can be increased by increasing the number of times of electroforming as compared with the other annular portion 98 located in the central portion in the axial direction. That is, in the stent 106 of the present embodiment, the cross-sectional shape changes in the length direction with a shape in which the thickness dimension changes in the length direction. In addition, by making the axial end portion thicker than the central portion, the axial end portion may have a larger outer diameter size, a smaller inner diameter size, or both than the central portion. . Moreover, this thick part may be provided in one edge part of an axial direction, and may be provided in an axial direction both ends.

As described above, in the deformed cylindrical stent 106 in which the axial end portion is thicker than the central portion, the rigidity of the axial end portion is made larger than that of the central portion. It is also possible to prevent restenosis by suppressing the lifting from the blood vessel at the axial end while securing the degree of freedom.

In addition, after the first electroforming, the mask is formed again, and the second electroforming is performed so as to straddle over the annular portions 98 and 98 adjacent to each other located at the end in the axial direction. It is also possible to form an annular portion 98 that is offset by a half pitch in the axial direction so as to cover the outer periphery. Since it is possible to reinforce the rigidity of the axial end portion with such a complicated structure, a large degree of freedom in design is realized.

In the stent 106 of this embodiment, it is preferable that the rigidity of the end portion on the outer side in the axial direction is substantially the same as or smaller than that of the central portion at the axial end where the rigidity is increased compared to the central portion. . Thereby, the load which the axial direction terminal part of the stent detained so that it may bite into the blood vessel wall can exert on the blood vessel wall can be reduced. Such a rigid end portion can be realized, for example, by forming only the end portion with a soft metal, or by adjusting the number of times of electroforming, a mask or the like to reduce the thickness or width of the end portion.

Furthermore, since the stents 90, 104, and 106 as described above are manufactured by electroforming, the design freedom of the cross-sectional shape of the struts 102 constituting the skeleton is also simple rectangular cross-section in the conventional laser processing. On the other hand, a large degree of freedom can be secured. For example, FIGS. 19A and 19B show the cross-sectional shape of the strut 102 whose width dimension changes from the inner peripheral surface toward the outer peripheral surface. That is, in the embodiment shown in FIGS. 19A and 19B, the cross-sectional shape of the strut 102 has a deformed structure that changes in the thickness direction. In FIGS. 19A and 19B, the upper side is the outer peripheral side, that is, the side in contact with the blood vessel wall, and the lower side is the inner peripheral side, that is, the side located in the blood vessel lumen.

Specifically, as shown in FIG. 19A, a strut 102 having a substantially triangular cross section can also be used. In the strut 102 having such a shape, the width dimension is reduced from the inner peripheral surface toward the outer peripheral surface, and the side in contact with the blood vessel wall is gradually narrowed. Therefore, when the stent is expanded, the pressing force against the blood vessel wall of the stent is increased. Can be concentrated on the tapered portion of the strut 102. As a result, the blood vessel can be expanded with a smaller pressing pressure of the stent, in other words, with the expansion pressure of the stent. In addition, even when the blood vessel wall is hard, such as a calcified lesion of a blood vessel, the taper portion of the strut 102 bites and breaks against the calcified lesion portion, so that it is difficult to expand with a conventional rectangular cross section. Vascularized vessels can also be dilated.

Further, as shown in FIG. 19 (b), a strut 102 having a substantially inverted triangular cross section can also be employed. In the strut 102 having such a shape, the width dimension is reduced from the outer peripheral surface toward the inner peripheral surface, and the side located in the blood vessel lumen is gradually narrowed. It can be suppressed as much as possible. Moreover, since it is difficult for stagnation to occur in the blood flow, the risk of blood clots and the like being generated can be reduced. Furthermore, since the area exposed to the blood vessel lumen is small, the period until it is covered with the vascular endothelial cells can be shortened, and the strut 102 is buried in the blood vessel at an early stage. From this, the enlargement of the vascular endothelium can be suppressed, and the stent placement portion can be cured in a relatively short period of time.

The strut 102 having such a shape can be formed by adjusting the shape of the mask during electroforming to a desired shape by etching or the like, and can greatly improve the degree of freedom of setting the cross-sectional shape. That is, a stent whose cross-sectional shape changes in the thickness direction as shown in FIGS. 19A and 19B can be easily manufactured by electroforming only by appropriately setting the masking shape. However, the cross-sectional shape of the strut 102 is not limited to the approximate triangular shape or the generally inverted triangular shape shown in FIGS. 19A and 19B, and for example, a semicircular shape or a double tapered shape is also employed. Can be done.

Furthermore, since the stents 90, 104, and 106 as described above are manufactured by electroforming, the cross-sectional shape of the link portion 100 that connects the annular portions 98 and 98, as well as the degree of freedom in designing the strength and the brittleness are greatly increased. Can be secured. In this way, by providing a partially low-strength portion in the skeleton of the stent, the fragile portion applied when the expanded stent is bent is easily deformed or cut, so that the stent has a shape of a body lumen. It is easy to follow. In addition, when an opening is formed in a stent corresponding to a branched blood vessel or the like, an operator can easily perform an operation of cutting or expanding the fragile site.

Here, in the stents 90, 104, and 106, in the skeleton, the link portion 100 constitutes a weakened portion whose strength is smaller than that of the annular portion 98. By producing such a link portion 100 by electroforming, only a thin shape in the width direction of the strut 102 can be formed by laser processing of the conventional structure, but not only the thin shape but also the thickness of the strut 102. Thin shapes can also be formed in the vertical direction. Moreover, the cross-sectional shape of the link part 100 was only a simple rectangular cross section by the conventional laser processing, but shapes other than a rectangle can also be formed.

Specifically, for example, as shown in FIGS. 20A to 20C, the position of the link portion 100 in the thickness direction can be appropriately changed with respect to the annular portions 98 and 98. In FIG. 20, the upper side shows the blood vessel wall side, and the lower side shows the blood vessel lumen side. That is, in FIG. 20 (a), the annular portions 98, 98 are connected by the link portion 100 on the blood vessel wall side, while in FIG. 20 (b), the annular portions 98, 98 are the link portions at the central portion in the thickness direction. 100 are connected. In FIG. 20C, the annular portions 98 and 98 are connected by the link portion 100 on the blood vessel lumen side. Furthermore, it is possible to combine the link portions 100 positioned on the blood vessel wall side, the central portion, and the blood vessel lumen side. In FIG. 20, the strut 102 and the link portion 100 are shown as a rectangular cross section, but FIG. 20 simply shows the relative positions of the annular portions 98 and 98 and the link portion 100, and the strut 102 and the link portion 100. The shape of is not limited in any way.

Thus, in conventional laser processing, since one pipe is formed to penetrate in the thickness direction, the annular portion and the link portion can only be formed with the same thickness, whereas the stent 90 , 104, 106 are manufactured by electroforming, the thickness dimension of the link portion 100 can be reduced. Thereby, the link part 100 can be formed thinly and thinly, and when the link part 100 is cut | disconnected, it is made easy to cut | disconnect more easily than before. Conventionally, a method of forming the annular portion 98 and the link portion 100 separately and then fixing them together has been adopted. However, by manufacturing the stents 90, 104, and 106 by electroforming, The link part 100 is integrally formed, and manufacturing can be facilitated while ensuring high dimensional accuracy. Furthermore, since the cut surface of the link part 100 is made small, irritation | stimulation by a cut surface contacting a blood vessel wall etc. can be suppressed as much as possible.

Further, the design of the position of the link portion 100 can be changed as appropriate in the width direction of the strut 102, and it can be formed at the end in the width direction with respect to the strut 102, but is shown in FIG. As described above, the link portion 100 is preferably formed in the center portion in the width direction of the strut 102, that is, in the center portion in the width direction in the bent portion of the annular portion 98 in the above-described embodiment. In particular, as shown in FIG. 21, the link portion 100 is preferably located at the central portion of the strut 102 in the thickness direction. Thereby, the possibility that the cut surface of the link part 100 contacts the blood vessel wall is further reduced, and the discomfort given to the patient can be further reduced.

21 also shows the strut 102 and the link portion 100 as a rectangular cross section, but FIG. 21 merely shows the relative positions of the annular portion 98 and the link portion 100. The shape is not limited at all.

Next, FIGS. 22 and 23 show a stent 108 as still another embodiment. The stent 108 is generally cylindrical and extends linearly as a whole.

Here, the cross-sectional shape of the strut 102 in the stent 108 of this embodiment is formed as a deformed structure that is different in the thickness direction (vertical direction in FIG. 19B) as shown in FIG. 19B. The width dimension (the dimension in the left-right direction in FIG. 19B) is increased from the inner peripheral surface toward the outer peripheral surface.

That is, in this embodiment, the cross-sectional shape of the strut 102 is a substantially inverted triangle. Further, in this embodiment, the edge portion in the inverted trapezoidal cross-sectional shape shown in FIG. 23B is subjected to chamfering such as sand blasting, chemical polishing, electrolytic polishing, etc., so that it is shown in FIG. 19B. A generally inverted triangular cross-sectional shape is formed. In the cross-sectional shape before chamfering shown in FIG. 23 (b), if the width dimension of the outer peripheral surface is W, it is preferably 60 mm ≦ W ≦ 180 mm, and more preferably 80 mm ≦ W ≦ 130 mm. It is set within the range, and in this embodiment, W = 125 mm.

Therefore, in this embodiment, as shown in FIG. 24, the central angle β in the arc of the inner peripheral surface is made smaller than the central angle α in the arc of the outer peripheral surface of the strut 102 (β <α). That is, two points A and B on the outer peripheral surface where the width dimension is the largest in the cross-sectional shape of the strut 102 before the chamfering process (thick one-dot chain line in FIG. 24) pass through these points A and B. An arc Co that is convex to the side and a center of curvature O located on the inner peripheral side of the strut 102 are assumed as the center of curvature of the arc Co. Further, assume that two points on the inner peripheral surface of the strut 102 having the smallest width dimension in the cross-sectional shape of the strut 102 before the chamfering process are D and E, and an arc Ci passing through the points D and E with the point O as the center of curvature. To do. Here, when ∠AOB is the central angle α in the arc of the outer peripheral surface of the strut 102, and ∠DOE is the central angle β in the arc of the inner peripheral surface of the strut 102, the central angle β in the strut 102 is greater than the central angle α. It is also small. In this aspect, since the cross-sectional shape of the strut 102 is an approximately inverted triangle, it is understood that the central angle β in the arc of the inner peripheral surface of the strut 102 is substantially 0 (β≈0).

Further, in this embodiment, the depression angle θ on both side surfaces is made larger (α <θ) than the central angle α in the arc of the outer peripheral surface of the strut 102. The depression angle θ is formed by the intersection of the straight line AD and the straight line BE in FIG. 24 in the cross-sectional shape of the strut 102 before the chamfering process.

The central angle α of the outer peripheral surface is preferably 1 ° ≦ α ≦ 45 °, and more preferably 4 ° ≦ α ≦ 15 °. On the other hand, the central angle β of the inner peripheral surface is preferably set to 0 ° ≦ β ≦ 30 °, and more preferably set within a range of 0 ° ≦ β ≦ 10 °. Further, the depression angle θ on both side surfaces is preferably set to 15 ° ≦ θ ≦ 90 °, and more preferably set within a range of 30 ° ≦ θ ≦ 90 °. By setting the center angles α and β of the outer peripheral surface and the inner peripheral surface and the depression angles θ of both side surfaces within the above ranges, the effect of preventing fluid turbulence and the effect of reducing the outer diameter at the time of diameter reduction are stabilized. Can be demonstrated.

The stent 108 according to this embodiment having such a shape is manufactured as a metal skeleton in which the struts 102 and the link portions 100 are integrally formed by electroforming.

The stent 108 of this embodiment is capable of expanding and contracting in the radial direction. The stent 108 is mechanically contracted from a state before contraction shown in FIG. 22 to a predetermined size, and contracted as shown in FIGS. State. FIG. 25 shows one of the annular parts 98 constituting the stent 108, and the illustration of the other annular part 98 and the link part 100 connecting the annular parts 98, 98 is omitted.

Here, the cross-sectional shape of the strut 102 is an approximately inverted triangle as shown in FIG. 19B, and when the diameter is reduced, the circumferential direction in the strut 102 is formed at both axial end portions of the annular portion 98. Adjacent parts abut. At that time, as shown in FIG. 26 (b), the peripheral end portions on the outer peripheral side in the cross-sectional shape of the strut 102 are in contact with each other, so that the diameter of the stent 108 is limited and the diameter of the stent 108 is reduced. The outer diameter dimension of the stent 108 is defined.

In the stent 108 of this embodiment having the above-described structure, since the cross-sectional shape of the strut 102 is a substantially inverted triangle, for example, compared to a stent having a conventional structure having a rectangular cross-section, the stent 108 has an internal structure. The part exposed to the peripheral blood flow can be reduced. This prevents the stent 108 from obstructing the blood flow and prevents the blood flow from becoming slow or turbulent (turbulent) due to the stent 108 being placed in the blood vessel. Is done. Therefore, the formation of a thrombus in a blood vessel or heart due to turbulence is suppressed, and restenosis at the indwelling position of the stent 108 due to the attachment of the thrombus to the stent 108 is effectively prevented. obtain.

Moreover, since the area exposed from the blood vessel wall is reduced, it is buried in the vascular endothelial cells at an early stage. That is, since the blood vessel wall that has cracked due to the placement of the stent 108 can be healed in a relatively short time, the enlargement of the vascular endothelial cells is suppressed and a thrombus adheres to the enlarged vascular endothelial cells. Thus, restenosis at the indwelling position of the stent 108 can be avoided. However, even if the vascular endothelial cells are enlarged, a lot of gaps are formed on the inner peripheral side of the stent 108, so that the vascular endothelial cells enter the gaps and the growth of the vascular endothelial cells to the inner peripheral side is suppressed. Thus, the risk of restenosis at the indwelling position of the stent 108 can be further reduced.

Furthermore, for example, in a stent in which the skeleton of the conventional structure has a rectangular cross section, when the diameter is reduced, the corners on the inner peripheral side of the skeleton cross section quickly contact each other, and the further diameter reduction is limited. In the stent 108, since the cross-sectional shape of the strut 102 is an approximately inverted triangle, the strut 102 does not abut on the inner peripheral side of the strut 102 but abuts on the outer peripheral side. As a result, the stent 108 of this embodiment is not limited in diameter reduction as compared with a stent having a conventional structure, and the outer diameter dimension at the time of diameter reduction can be further reduced. In particular, as in this aspect, by increasing the depression angle θ on both side surfaces compared to the central angle α of the outer peripheral surface, the possibility of contact on the inner peripheral side is further reduced, so the outer diameter size at the time of diameter reduction Can be reliably reduced. As a result, the delivery of the stent 108 and the delivery catheter equipped with the stent 108 can be improved.

In particular, in the cross-sectional shape of the strut 102, it is preferable that the depression angle θ on both sides is set to 15 ° ≦ θ ≦ 90 °, whereby the circumferential dimension in the cross-sectional shape of the strut 102 can be kept small. For example, even when the wave number in the circumferential direction of the stent (the number of repeating units in the circumferential direction) is large, the outer diameter dimension when the diameter is reduced can be stably reduced.

Next, FIG. 27 shows a stent 110 as still another embodiment. The stent 110 of this aspect has a skeleton structure composed of the struts 102 and the link portions 100, and the cross-sectional shape of the struts 102 is the shape shown in FIG.

The stent 110 of this embodiment has a deformed cylindrical shape in which the outer diameter dimension at both end portions in the axial direction (vertical direction in FIG. 27) is larger than the outer diameter dimension at the central portion in the axial direction. The stent 110 of this aspect is, for example, a plurality of annular portions 98 positioned at both axial end portions relative to the straight cylindrical stent 108 shown in FIG. 22 than the annular portion 98 positioned at the axial central portion. Also, it can be formed by increasing the number of times of electroforming to make it thick. That is, it is preferable that the stent 110 of this aspect has a laminated structure made of a plurality of types of metals. Such a laminated structure does not need to be formed over the entire stent, and a specific portion of the stent may be a laminated structure. Further, the shape of the inner hole of the stent 110 is not limited in any way. For example, a straight shape extending in the axial direction may be used, and both end portions may have larger diameters than the central portion in the axial direction.

Furthermore, the stent 110 according to this aspect has both end portions in the axial direction being thicker than the central portion in the axial direction, so that the rigidity of both end portions is larger than that in the central portion.

Also in the stent 110 of this embodiment having the above-described shape, since the cross-sectional shape of the skeleton is the same as that of the stent 108, the same effect as that of the stent 108 can be exhibited. In addition, in this aspect, since both end portions in the axial direction are larger in outer diameter than the central portion in the axial direction and have increased rigidity, the axial end portions of the stent 110 are lifted from the blood vessel. Suppressed and stably placed at the stenosis site of the blood vessel. In particular, when the axial end of the stent is separated from the blood vessel in a state where it is placed in the blood vessel, there is an increased possibility that blood flow is disturbed and a thrombus is formed. Therefore, as shown in this aspect, the lift from the blood vessel is suppressed at both axial ends of the stent 110, so that restenosis at the stent placement position can be more effectively prevented. Furthermore, by reducing the rigidity of the axial end portion, the load exerted on the blood vessel wall by the axial end portion of the stent placed so as to bite can be reduced.

Next, FIG. 28 shows a stent 112 as another embodiment. The stent 112 of this embodiment has a substantially Y-shaped skeleton structure composed of the struts 102 and the link portions 100, and the cross-sectional shape of the struts 102 is the shape shown in FIG.

The stent 112 of this embodiment may be formed by, for example, forming the main cylinder portion 114 and the branch cylinder portion 116 separately and joining them together by means such as welding. 114 and the branch cylinder part 116 may be formed integrally.

Also in the stent 112 of this embodiment having such a shape, since the cross-sectional shape of the strut 102 is the same as that of the above-described embodiment shown in FIG. 19, the same effect as the stent 108 of this embodiment is exhibited. obtain. In particular, the stent 112 according to this embodiment has a branched shape and can correspond to a complicated shape such as a blood vessel of a living body, and blood flow disturbance is suppressed even at the branched portion of the blood vessel, thereby further reducing the restenosis of the blood vessel. It can be effectively prevented.

[Example]
As Example 1 of this invention, a stent 108 having a structure according to the embodiment shown in FIG. 19 shown in FIGS. 22 and 23 was virtually manufactured on a computer. Further, as Example 2 of the present invention, as shown in FIG. 29, a stent 118 is adopted in which the cross-sectional shape of the skeleton is reduced to a width dimension from the inner peripheral surface to the outer peripheral surface to form an approximate triangle. As a comparative example, a stent 120 having a conventional structure with a rectangular cross section as shown in FIG. 30 was adopted, and each was virtually manufactured on a computer. In addition, while Example 2 and the stent 118,120 of a comparative example shown by FIG.29,30 have shown the thing of the shaping | molding state before diameter reduction, these stents 108 of Example 1,2 and a comparative example 108, 118 and 120 were prepared assuming that the edge portions were not chamfered.

The outer diameters of the stents 108, 118, and 120 of Examples 1 and 2 and the comparative example before diameter reduction were each set to φ = 3 mm (see FIG. 22). Furthermore, while the width dimension of the outer peripheral surface of the cross section of the strut 102 in the first embodiment is W = 125 mm (see FIG. 23B), the width dimension of the inner peripheral surface of the cross section of the strut 102 ′ in the second embodiment (FIG. b) was also designated W. Furthermore, the width dimension of the outer peripheral surface of the cross section of the strut 122 in the comparative example was W1 = 100 mm (see FIG. 30B). In addition, the thickness dimensions of the struts 102, 102 ', 122 of Examples 1 and 2 and the comparative example were set to the same T = 0.1 mm (see FIG. 23B, etc.).

Then, diameter reduction processing was performed on the stents 108, 118, and 120 of Examples 1 and 2 and the comparative example that were virtually manufactured on a computer, and the respective outer diameter dimensions were compared. The perspective view and the axial view of the annular portion 98 obtained by reducing the diameter of the stent 108 of Example 1 are shown in FIGS. 25 and 26, and the stent 118 of Example 2 and the comparative example. , 120 are a perspective view and an axial view of the annular portion 98 obtained by reducing the diameter. Thus, the outer diameter dimensions of the stents 108, 118, 120 of Examples 1 and 2 and the comparative example subjected to the diameter reduction treatment are φ ′ (see FIG. 26A), φ1 (see FIG. 32), and φ2, respectively. (See FIG. 34). Note that “ANSYS R14.5” manufactured by ANSYS was used as software for performing the analysis by reducing the diameter.

As a result, φ1 = 1.80 mm and φ2 = 1.70 mm, whereas φ ′ = 1.68 mm. That is, the stent 108 in which the cross-sectional shape of the strut 102 is an approximately inverted triangle is the same as the stent 118 in which the cross-sectional shape of the strut 102 ′ is an approximate triangle or the stent 120 in which the cross-sectional shape of the strut 122 is a conventional structure. On the other hand, it is shown that the outer diameter size when the diameter reduction process is performed becomes smaller.

The reason why the outer diameter of the stent 108 of Example 1 is smaller than that of the stent 118 of Example 2 and the stent 120 of Comparative Example after the diameter reduction processing is that in the stents 118 and 120 of Example 2 and Comparative Example, FIG. As shown in FIG. 32 (b) and FIG. 34 (b), when the diameter reduction process is performed, the inner peripheral sides of the skeletons adjacent in the circumferential direction are brought into contact with each other quickly, and further diameter reduction is limited. Is done. On the other hand, as shown in FIG. 26B, the stent 108 of Example 1 has a skeleton that is adjacent in the circumferential direction because the width of the inner peripheral surface is smaller than the width of the outer peripheral surface. It is surmised that the diameter reduction is not limited until the outer peripheral sides of the two come into contact with each other, and the outer diameter dimension becomes smaller.

As a result, the outer diameter of the stent 108 of the first embodiment can be made smaller than that of the stent 118 having the substantially triangular cross section of the second embodiment and the stent 120 having the rectangular cross section of the conventional structure. Since the outer diameter at the time of mounting can be reduced, good delivery can be exhibited.

In addition, the flow velocity in the vicinity of each strut was confirmed using the stents 108, 118, and 120 of Examples 1 and 2 and the comparative example. The results of Examples 1 and 2 are shown in FIGS. 35 and 36, respectively, and the result of the comparative example is shown in FIG. The stents 108, 118, and 120 shown in FIGS. 35 to 37 are in the molded state shown in FIGS. 23, 29, and 30, respectively, and the outer diameter of each is set to φ = 3 mm. 35 (a), 36 (a) and 37 (a) show the velocity distribution in the vicinity of the blood vessel wall surface as vectors, and FIGS. 35 (b), 36 (b) and 37 (b) show blood vessels. The velocity distribution in the vicinity of the wall surface is shown by a plane. 35 to 37 are difficult to see because the analysis results output and displayed as colored images are displayed in gray scale for patent application, but the flow is fast in the dark gray part in the figure. On the other hand, the light color portion indicates that the flow is slow, and the flow velocity changes stepwise corresponding to the change from the dark gray portion to the light color portion. This analysis was performed using software “ANSYS R14.5” manufactured by ANSYS.

As a result of comparing FIGS. 35 to 37, compared to FIGS. 36 (a) and 37 (a), FIG. 35 (a) has a large and many dark gray vector lines representing a fast flow as a whole. . 36 (a) and 37 (a), the reason why the number of vector lines is small is that the lines are thin and the flow is slow, so that they are not displayed large as vector lines, or there is almost no flow itself. This is because there seems to be no vector line. On the other hand, compared with FIGS. 36 (b) and 37 (b), 35 (b) shows many lighter portions as a whole. From this, it is shown that the flow velocity of the fluid passing through the vicinity of the strut of the stent 108 of Example 1 is faster than the flow velocity of the fluid passing through the vicinity of the strut of the stent 118 of Example 2 and the stent 120 of the comparative example. . As a result, in the stent 108 of Example 1, the fluid can flow without stagnation at the stent placement position in the lumen compared to the stent 118 of Example 2 and the stent 120 of Comparative Example. In particular, when the stent 108 is indwelled in a blood vessel, the effect of preventing the occurrence of thrombus due to blood retention and turbulence, and restenosis at the stent indwelling position due to the thrombus adhering to the stent is further enhanced. It is suggested that it can be demonstrated.

The reason for exhibiting such an effect is that the cross section of the strut 102 of the stent 108 of the first embodiment is a substantially inverted triangle, and therefore, the strut 102 ′ having a cross section of the general triangle as in the second embodiment and a rectangular cross section as in the comparative example. Compared to the struts 122, it is presumed that the portion protruding to the inner peripheral side can be made smaller, and the inhibition of the flow of fluid passing through the inside of the stent 108 is suppressed as much as possible.

In the stent 118 of the second embodiment, the cross-sectional shape of the strut 102 ′ is generally triangular, and the inner peripheral sides of the struts contact with each other relatively early. There is a possibility that the outer diameter reduction effect at the time cannot be fully enjoyed. Further, when the stent 118 is indwelled in the lumen, a portion that protrudes from the lumen wall to the inner peripheral side becomes relatively large, and the protruding portion serves as a barrier for the fluid. There is a risk that the flow of

However, the outer peripheral side is tapered in the cross-sectional shape of the strut 102 ', and the stent 118 is positioned so that the tapered tip of the stent 118 bites into the lumen wall, thereby effectively positioning the stent 118 in the lumen. Can be demonstrated. In particular, even in the case where a blood vessel wall is hardened like a calcified lesion and the skeleton of the conventional structure has a rectangular cross section, it is difficult to expand the blood vessel. Since the effect of splitting on the lesion site is exerted, a blood vessel that is difficult to expand with a conventional rectangular cross section can be expanded by employing the stent 118 as in the second embodiment.

Therefore, depending on the condition of the patient and the lesion site, a stent having a substantially triangular cross-sectional shape can be suitably employed. As described above, the stents 108, 110, 112, and 118 of the present invention have excellent technical significance because the stent corresponding to the state of the stenosis site and the site where the stenosis occurs can be manufactured with a large degree of design freedom. It is what you are doing.

As described above, the problem to be solved by the invention different from the present invention described above (hereinafter referred to as the above invention) depends on the site where the stenosis occurs in the lumen where the stent is placed, the state of the stenosis site, and the like. It is an object of the present invention to provide a stent having a novel structure in which the performance of the stent can be adjusted with a greater degree of design freedom, and the shape corresponding to the lumen of a blood vessel or the like can be realized with a good yield. .

That is, according to the first aspect of the present invention, in the stent having a tubular structure due to the structure of the skeleton that can be expanded and contracted in the radial direction, and a deformed structure in which the cross-sectional shape of the skeleton changes in the thickness direction, The skeleton is a metal skeleton formed by at least one of electroforming, etching, spraying, and vapor deposition.

In the stent having the structure according to this aspect, the skeleton has a cross-sectional shape different from a conventional simple rectangular cross-sectional shape, so that the stenosis occurs in the lumen where the stent is placed, the state of the stenosis, or the like. Accordingly, the stent performance and the like can be adjusted efficiently with a large degree of design freedom.

Also, since the skeleton is formed by at least one of electroforming, etching, spraying, and vapor deposition, the stent has a shape corresponding to the shape of the lumen from the beginning. Therefore, the portion to be excised can be reduced as compared with the stent manufactured by laser processing, and the stent can be manufactured with a good yield.

The second aspect of the present invention is the stent according to the first aspect, wherein the cross-sectional shape of the skeleton is such that the width dimension is increased from the inner peripheral surface toward the outer peripheral surface.

In the stent having the structure according to the present aspect, the cross-sectional width dimension of the portion exposed to the fluid in the lumen such as blood can be reduced as compared with the stent having the conventional structure having a skeleton having a simple rectangular cross section. . As a result, blood or the like can flow more easily in the placement position of the stent in the lumen of a blood vessel or the like than a stent having a conventional structure, and stagnation or turbulence of blood or the like is suppressed. As a result, troubles such as formation of thrombus and restenosis of the blood vessel at the indwelling position of the stent due to the attachment of the thrombus to the stent can be effectively avoided.

In addition, since the cross-sectional width of the skeleton is relatively large in the circumferential direction on the outer peripheral surface of the stent, the pressing force on the inner surface of the lumen such as a blood vessel can be dispersed, resulting in local force concentration. The occurrence of cracks in the lumen wall can be suppressed, and the healing period of the cracks generated in the lumen wall can be shortened. Thereby, for example, restenosis caused by enlargement of vascular endothelial cells in a cracked portion of the blood vessel can be effectively suppressed. Even if the vascular endothelial cells are enlarged, a relatively large gap is provided between the skeletons having a reduced cross-sectional width on the inner peripheral surface side of the stent, so that the vascular endothelial cells are separated from the inner peripheral surface of the stent. Further, the enlargement toward the inward direction is suppressed, and a further inhibitory effect against the restenosis of the blood vessel is exhibited.

Further, in the stent having the structure according to the present aspect, the circumferential width dimension in the skeleton cross section is reduced toward the inner peripheral side, so that when the diameter is reduced by being attached to the delivery catheter, The problem that adjacent skeletons contact each other on the inner peripheral side having a small peripheral length and the amount of diameter reduction is limited is solved. Therefore, while ensuring the cross-sectional area of the skeleton and realizing the required strength and the like, it is possible to improve the delivery performance by setting the size capable of reducing the diameter sufficiently small.

In the stent according to this aspect, the cross-sectional shape of the skeleton is not particularly limited as long as the width dimension is increased from the inner peripheral surface toward the outer peripheral surface, but it is particularly preferable that the skeleton is an approximately inverted triangle. More preferably, the cross-sectional shape is an approximately inverted isosceles triangle.

According to a third aspect of the invention, there is provided the stent according to the first or second aspect, wherein in the cross-sectional shape of the skeleton, the depression angles on both sides in the circumferential direction are made larger than the central angle in the arc of the outer circumferential surface. It is what.

In the stent having the structure according to this aspect, both side surfaces in the circumferential direction in the skeleton cross-section enter a direction approaching each other toward the inner circumferential side rather than the radial line in a state before the diameter reduction. Therefore, even when the diameter is reduced, it is avoided that the skeletons adjacent in the circumferential direction come into contact with each other on the inner circumference side at an early stage and the amount of diameter reduction is limited. As a result, it is possible to realize a stent that can be deformed to a smaller diameter while ensuring the circumferential length of the skeleton on the outer peripheral surface of the stent and avoiding the action of a local pressing force on a blood vessel or the like.

The fourth aspect of the present invention is the stent according to the second or third aspect, wherein, in the cross-sectional shape of the skeleton, the included angles θ on both sides in the circumferential direction are set to 15 ° ≦ θ ≦ 90 °. It is what.

In the stent having the structure according to this aspect, the depression angles on both side surfaces in the circumferential direction are relatively small, so that the circumferential dimension in the cross-sectional shape of the skeleton is kept small. As a result, for example, even when the wave number in the circumferential direction of the stent (the number of repeating units in the circumferential direction) is relatively large, an increase in the outer diameter of the entire stent is avoided and stable even when the diameter is reduced. Thus, the diameter can be reduced.

The fifth aspect of the present invention is the stent according to the first to fourth aspects, wherein the cross-sectional shape of the skeleton is changed in the length direction to have a deformed cylindrical shape.

In the stent having the structure according to this aspect, even when placed in an irregularly shaped lumen such as a blood vessel, a shape corresponding to the lumen is realized with high accuracy, and the burden on the procedure is reduced for the practitioner. The burden on the living body is reduced for the patient. Further, even in the stent itself placed in a shape corresponding to the lumen, distortion and residual stress are reduced, and good shape stability and durability can be realized.

A sixth aspect of the above invention is the stent according to the fifth aspect, wherein a branched portion is provided and the number of the tubular portions is changed in the length direction.

In the stent having the structure according to this aspect, a stent that can be easily applied to a bifurcation portion such as a bifurcation in a lumen such as a blood vessel can be realized.

The seventh aspect of the present invention is the stent according to the fifth or sixth aspect, wherein the stent has a deformed cylindrical shape whose diameter is changed in the length direction.

In the stent having the structure according to this aspect, a stent that can be applied satisfactorily to a site where the inner diameter changes in the length direction in a lumen such as a blood vessel can be realized. In addition, the stent of this mode can be combined with the sixth mode, so that at least one tube portion of the stent having a branch portion can have a tapered tube shape or the like.

According to an eighth aspect of the present invention, in the stent according to any one of the first to seventh aspects, rigidity at at least one end in the axial direction is greater than that of the central portion.

In a stent having a structure according to this embodiment, only a predetermined portion in the length direction is masked and formed by electroforming, etching, thermal spraying, or vapor deposition, so that the thickness dimension of a specific portion is increased or the material is different. The rigidity can be adjusted. In particular, in the stent of this aspect, the rigidity of the axial end portion that is easily deformed is increased for structural reasons, so that the axial end portion is separated from the lumen while being placed in the lumen. It can also be effectively prevented from causing stenosis.

That is, the rigidity of the axial end of the stent is improved because, for example, when the axial end of the stent is left in the blood vessel, the blood flow is disturbed and a thrombus is formed. By enlarging and stably indwelling in the blood vessel, restenosis at the stent indwelling position can be effectively prevented.

A ninth aspect of the invention is the stent according to the eighth aspect, wherein the end portion whose rigidity is increased as compared with the central portion is reduced in rigidity at a terminal portion on the outer side in the axial direction. Is.

In the stent having the structure according to this aspect, since the rigidity of the end portion at the end of the stent is reduced, the load exerted on the lumen by the end portion of the stent can be suppressed. In addition, since the skeleton is formed of metal, the adjustment of the rigidity at the end portion can be realized by forming only the end portion of the stent with a soft metal, or by reducing the thickness or width. . Preferably, the rigidity of the end portion is set to be substantially the same as or smaller than that of the central portion.

According to a tenth aspect of the present invention, in the stent according to any one of the first to ninth aspects, the skeleton has a laminated structure of a plurality of types of metals.

In a stent having a structure according to this aspect, it is possible to form a laminated structure of a plurality of types of metals by electroforming, thermal spraying, or vapor deposition. For example, by adopting a metal material whose surface layer is more ductile than the core layer, the core layer ensures the strength of the stent while relaxing the stress on the surface when the stent expands or contracts and prevents cracks from occurring It is also possible to do. In addition, by adopting a metal material with a smaller ionization tendency in the surface layer than in the core layer, it is possible to achieve biocompatibility, radiopacity, etc. by the surface layer while ensuring the required strength characteristics in the core layer. It becomes possible. In this embodiment, it is sufficient that at least a part of the skeleton has a laminated structure, and the entire skeleton does not have to have a laminated structure.

According to an eleventh aspect of the present invention, in the stent according to any one of the first to tenth aspects, the weakened portion partially reduced in strength is at least one of electroforming, thermal spraying, and vapor deposition in the skeleton. It is formed by one.

In a stent having a structure according to this aspect, by providing a weakened portion in the skeleton, for example, it is divided after placement to obtain a stent shape that conforms to the lumen shape, or is cut or deformed during placement treatment for branching. Forming the opening by a technique can be easily realized.

In particular, by forming such fragile parts by electroforming, etching, thermal spraying, and vapor deposition, it does not require a cumbersome operation such as making a separate part from the other part of the skeleton and then fixing the fragile part. It can be provided with dimensional accuracy. However, the main body and the fragile portion of the skeleton need not be formed by the same means among electroforming, thermal spraying, and vapor deposition, and may be formed by different means. In addition, the position and shape of the fragile portion can be arbitrarily set, and the degree of freedom in design can be improved.

In a twelfth aspect of the invention, in the stent according to the eleventh aspect, the fragile portion is easily deformed with a smaller cross-sectional area than other portions of the skeleton.

In the stent having the structure according to this aspect, the fragile portion is stably cut by forming the fragile portion thinner than other portions of the skeleton, for example, to further facilitate the bending of the stent. In particular, since the fragile portion is formed by electroforming, thermal spraying, or vapor deposition, for example, it is possible to reduce the thickness of the fragile portion only in the thickness direction, change the material, or the like.

In a thirteenth aspect of the present invention, in the stent according to any one of the first to twelfth aspects, the skeleton is provided with a drug containing recess for storing a drug on the surface.

In the stent having the structure according to this aspect, since the skeleton is formed by electroforming, thermal spraying, or vapor deposition, a drug containing recess for containing a drug is provided on the surface of the skeleton at the same time as molding, or a convex is provided. It is also possible to provide a medicine housing recess that is provided simultaneously with molding and is relatively concave. And it becomes possible to hold | maintain a chemical | medical agent in a chemical | medical agent accommodation recessed part, and to detain in a lumen | bore by the uneven structure of the surface. In addition, the chemical | medical agent accommodation recessed part in this aspect can be formed in any surface of the internal peripheral surface of a cylindrical surrounding wall, and an outer peripheral surface. Moreover, the medicine accommodating recess in this aspect may be not only a bottomed shape but also a through hole formed by electroforming or the like.

In addition, it is desirable that the size of the drug containing recess in this aspect is about 10 to 30 μm in opening size, which further reduces the patient's feeling of foreign matter and may adversely affect the strength of the stent. Avoided as much as possible.

The invention described above is not limited by the specific description of each embodiment, and can be implemented in a manner to which various changes, modifications, improvements, etc. are added based on the knowledge of those skilled in the art. Such embodiments are also included in the scope of the invention as long as they do not depart from the spirit of the invention.

Furthermore, in the embodiment shown in FIG. 27, the rigidity is increased by making both end portions in the axial direction thick, but in the straight stent in the embodiment shown in FIG. 22, the rigidity is large as both end portions in the axial direction. 27, the thickness of the stent in the aspect shown in FIG. 27 is made substantially constant over the entire length in the axial direction, and a metal having high rigidity is adopted as both end portions in the axial direction. You may enlarge it.

22, 27, and 28, the generally inverted triangle is exemplified as the shape in which the circumferential width dimension in the cross-sectional shape of the strut 102 gradually decreases from the outer peripheral side toward the inner peripheral side. For example, an inverted trapezoidal shape or a semicircular shape that protrudes toward the inner periphery may be used. However, in the present invention, it is also possible to have a deformed structure in which the circumferential width dimension of the skeleton cross section gradually increases from the outer peripheral side toward the inner peripheral side, as in the stent 118 of Example 2 described above. In addition to the illustrated approximate triangle, the shape may be a trapezoid or a semicircular shape that protrudes toward the outer periphery. This reduces the pressing area of the outer peripheral surface of the stent to the blood vessel in the skeleton and concentrates the pressing force, thereby improving the positioning action of the stent on the blood vessel and Misalignment can also be suppressed. In addition, since the pressing force is concentrated on the blood vessel wall, not only can an effective expansion action be exerted on a hardened blood vessel such as a calcified lesion, but also a non-hardened blood vessel However, it is possible to expand to a desired dimension with a smaller expansion force.

Further, in the present invention, a deformed structure in which the circumferential width dimension of the skeleton cross section is increased at the intermediate portion in the stent radial direction and gradually decreases toward both the outer peripheral side and the inner peripheral side, that is, for example, a rhombic cross section or a circular A cross section or an elliptical cross section is also possible. This makes it possible to concentrate the pressing force on the blood vessel on the outer peripheral surface of the skeleton while suppressing mutual interference in the circumferential direction at the inner peripheral ends of the skeletons adjacent to each other in the circumferential direction, which tends to be an obstacle when the stent is reduced in diameter. Therefore, it is possible to improve positioning performance and blood vessel expansion performance.

The stent having the structure according to the above aspect of the present invention is also applied to a flow diverter for treating a cerebral aneurysm. The flow diverter is, for example, a low-porosity blood flow bypass device improved for endovascular treatment of cerebral aneurysms. In addition, the said invention is applied also to the stent main body except the cover in covered stents, such as a flow diverter and a stent graft. The stent having the structure according to the above aspect of the present invention is also applied to the tip portion of the stent retriever system. The stent retriever system is, for example, a reticular cylindrical thrombectomy device for efficiently squeezing and removing a thrombus with a net.

38 and 39 show a stent 124 as a ninth embodiment of the present invention. The stent 124 is formed with a peripheral wall structure in which a first skeleton structure 126 and a second skeleton structure 128 are overlapped with each other inside and outside and integrated so as not to be separated. 38 and 39, the stent 124 is shown in a molded state before being contracted or expanded. In the following description, the axial direction refers to the front and back direction in FIG. 39, which is the axial direction in which the stent 124 extends.

More specifically, the first skeleton structure 126 is a sleeve structure having a mesh-shaped peripheral wall. That is, the first skeleton structure 126 includes a small-diameter wire 130a spirally wound in one circumferential direction (for example, clockwise in FIG. 39) and extending in the axial direction in the axial direction, and the other circumferential direction ( For example, a plurality of small-diameter wires 130b spirally wound in the counterclockwise direction in FIG. 39 and extending in the axial direction are arranged at equal intervals. Therefore, in such a mesh-like skeleton structure, a cell having a basic structure forming a rhombus opening having a substantially constant size is a repeated structure in which the circumferential direction and the axial direction are continuous at a constant pitch.

And each gap | interval of many cells in the mesh structure comprised by this wire 130a, 130b is made into the 1st gap | interval 132. FIG. That is, the gap 132 is repeatedly provided at a constant pitch in the circumferential direction and the axial direction with a substantially constant size.

Further, the second skeleton structure 128 is a cylindrical coil structure in which a linear body 134 that is a single strut extends spirally in the circumferential direction while being folded back in the axial direction. Note that the second skeleton structure 128 formed by one linear body 134 is connected by a link-like connecting portion 136 that connects portions adjacent to each other in the axial direction at a plurality of locations on the circumference. Connected and reinforced. Therefore, the second skeletal structure 128 has a repeating structure in which cells having a basic structure that is folded back in the axial direction at a substantially constant period are continuous at a constant pitch in the circumferential direction and the axial direction.

Then, a large number of second gaps 138 arranged in a spiral are formed by the cells of the second skeleton structure 128 formed at a constant pitch by folding the linear body 134 in the axial direction. The second gap 138 is repeatedly positioned at a constant pitch in the circumferential direction and the axial direction. In the present embodiment, the axial interval between the wires 130a and 130b and the axial folding pitch of the linear body 134 so that the first gap 132 is smaller than the second gap 138. (Cycle in the circumferential direction) and the like are set.

The stent 124 of the present embodiment is configured with a shape in which the second skeleton structure 128 is overlapped on the outer peripheral side with respect to the first skeleton structure 126 having such a structure. In the stent 124, the first skeleton structure 126 and the second skeleton structure 128 are overlapped with each other, and the first gap 132 is partitioned by the struts (linear bodies 134) of the second skeleton structure 128. The second gap 138 is divided by the wires 130a and 130b of the first skeleton structure 126 to be small.

Specifically, in the radial direction of the stent 124, the linear body 134 constituting the second skeleton structure 128 is located on the first gap 132, and the first skeleton is located on the second gap 138. The wires 130a and 130b constituting the structure 126 are located. Thereby, compared with the case where the 1st frame structure 126 and the 2nd frame structure 128 each exist alone, the magnitude | size of the clearance gap which penetrates a stent by radial direction is made small.

The axial dimensions of the first skeleton structure 126 and the second skeleton structure 128 are not limited in any way, and the other skeleton structure may protrude from the axial end of one skeleton structure. In the present embodiment, the axial dimensions of the first skeleton structure 126 and the second skeleton structure 128 are substantially equal. Further, the shape of the end portion in the axial direction of the first skeleton structure 126 is substantially the same as the shape of the second skeleton structure 128, so that the first skeleton structure 126 extends from the end portion in the axial direction of the second skeleton structure 128. Is not protruding. In addition, the radial width dimension of the first skeleton structure 126 and the second skeleton structure 128 is not limited in any way, but in the present embodiment, the radial width dimension of the second skeleton structure 128, that is, a linear shape. Compared to the thickness dimension of the body 134, the radial width dimension of the first skeleton structure 126, that is, the thickness dimension of the wires 130a and 130b is made smaller.

The stent 124 shaped as described above is manufactured by separately manufacturing the first skeleton structure 126 and the second skeleton structure 128 and then superimposing the first and second skeleton structures 126 and 128 on each other. However, in this embodiment, the stent 124 having the above-described shape is formed by electroforming. As a result, the first skeleton structure 126 and the second skeleton structure 128 are integrally formed in an inseparable manner. In the case where the first skeleton structure 126 and the second skeleton structure 128 are manufactured separately, the manufacturing method of each of the skeleton structures 126 and 128 is not limited in any way. A conventionally well-known manufacturing method etc. may be employ | adopted.

In addition, the stent 124 according to the present embodiment is delivered to the stenosis portion of the lumen by, for example, a stent delivery catheter, and is expanded by a balloon provided on the stent delivery catheter, thereby expanding the stenosis portion. . The material of the stent 124 is not limited in any way, but can be suitably formed from stainless steel, for example. Alternatively, if the stent 124 is a self-expanding stent that is automatically expanded according to the patient's body temperature after being released from the stent delivery catheter, for example, at least one of the first and second skeletal structures 126, 128. One is preferably formed of a nickel-titanium alloy.

Since the stent 124 of the present embodiment having the above-described structure is formed with a shape in which the first skeleton structure 126 and the second skeleton structure 128 are overlapped, the first skeleton structure 126 and the second skeleton structure 126 are formed. The size of the first gap 132 and the second gap 138 can be reduced as compared with the case where the skeleton structure 128 exists alone. Thereby, the re-projection of the plaque through the gap of the stent is suppressed, and the restenosis of the lumen can be effectively prevented.

In addition, since the stent 124 is integrally formed with a shape in which the first skeleton structure 126 and the second skeleton structure 128 are overlapped, the first skeleton structure 126 is placed when a stent having a small gap is placed. There is no need to perform multiple operations such as indwelling the second skeletal structure 128 and the second skeletal structure 128 at different timings, and the second skeletal structure 128 can be placed in the patient's lumen in one operation. Thereby, a burden of a patient or a practitioner can be reduced with certainty.

In particular, in the present embodiment, the second skeleton structure 128 is superimposed on the outer peripheral side with respect to the first skeleton structure 126, and the first skeleton structure 126 having a mesh structure is disposed on the inner peripheral side of the stent 124. On the other hand, a second skeletal structure 128 having a coil structure which is folded back in the axial direction and spirally extends in the circumferential direction is located on the outer peripheral side of the stent 124. That is, since the first gap 132, which is a smaller gap, is located on the inner peripheral side of the stent 124, the inner peripheral surface of the stent 124 can be made a smooth surface with less unevenness. It is possible to make it difficult to cause stagnation, turbulence, and the like of blood passing through the inner side of 124. Thereby, troubles such as formation of a thrombus and restenosis of a blood vessel at the indwelling position of the stent due to adhesion of the thrombus to the stent can be effectively avoided. In addition, since the second gap 138, which is a larger gap, is located on the outer peripheral side of the stent 124, the outer peripheral surface of the stent 124 can be formed with unevenness larger than the inner peripheral surface. When the diameter is expanded, the convex portion formed on the outer peripheral surface of the stent 124, that is, the second skeletal structure 128 can be stably bited into the lumen wall. Thereby, the positioning effect of the stent 124 in the lumen can be exhibited with high accuracy.

Further, since the stent 124 of the present embodiment is integrally formed by electroforming, it is troublesome to separately form the first skeleton structure 126 and the second skeleton structure 128 and fix them to each other during manufacture. The stent 124 can be easily manufactured without requiring such an operation. In addition, since at least the first skeleton structure 126 having a mesh shape is formed by electroforming, it is not necessary to perform end processing such as connecting ends of the wires 130a and 130b. It can be omitted.

Furthermore, FIG. 40 shows a stent 140 as a tenth embodiment of the present invention. In the stent 140 of the present embodiment, the first skeletal structure 142 in the mesh shape is an intermediate portion in the thickness direction of the second skeleton structure 128 in the coil shape extending in the axial direction while being folded back in the axial direction. Is located. In other words, the first skeleton structure 142 having a mesh shape is located in the second gap 138 in the second skeleton structure 128 having a coil shape. As in the ninth embodiment, the radial dimension of the first skeleton structure 142 is smaller than the radial dimension of the second skeleton structure 128. In the following description, the same members or parts as those of the ninth embodiment are denoted by the same reference numerals as those of the ninth embodiment in the drawings, and detailed description thereof is omitted.

That is, in the present embodiment, the second gap 138 is made small by forming the stent 140 into a shape in which the first skeleton structure 142 and the second skeleton structure 128 are overlapped. Specifically, in the radial direction of the stent 140, the wires 130a and 130b constituting the first skeletal structure 142 are positioned on the second gap 138, compared to the case of the second skeleton structure 128 alone. The second gap 138 is reduced. Thereby, compared with the case where the second skeleton structure 128 exists alone, the size of the gap that penetrates the stent in the radial direction is made smaller. The same effect as the stent 124 can be exhibited.

In particular, since the first skeleton structure 142 is located in the middle in the thickness direction of the second skeleton structure 128, the first skeleton structure 126 as in the ninth embodiment is the second skeleton structure 128. The radial dimension of the stent 140 can be reduced compared to the case where the stent 140 is located on the inner peripheral side. Thereby, the resistance of the blood flow at the indwelling position of the stent 140 can be reduced, and the risk that restenosis may occur due to adhesion of a thrombus or the like to the inner peripheral surface of the stent 140 can be reduced. Moreover, the foreign body feeling which a patient feels can be reduced stably.

In addition, the stent 140 of this embodiment is formed by electroforming. Thereby, for example, the first skeleton structure and the second skeleton structure as in the present embodiment are separately formed, and the stent can be easily manufactured even if it is difficult to overlap and fix the inside and outside. Can be done.

Next, FIG. 41 shows a stent 144 as an eleventh embodiment of the present invention. The stent 144 of the present embodiment has a structure in which a second skeleton structure 148 shown in FIG. 43 is overlapped on the outer peripheral side with respect to the first skeleton structure 146 shown in FIG. The second skeleton structures 146 and 148 are each meshed. A gap in the first skeleton structure 146 is a first gap 150, and a gap in the second skeleton structure 148 is a second gap 152. By superimposing the skeleton structure 148 on each other, the first and second gaps 150 and 152 are made smaller than in the case where each of them is in a single state. In the present embodiment also, the axial dimensions of the first skeleton structure 146 and the second skeleton structure 148 are substantially equal, and the first skeleton structure 146 and the second skeleton structure 148 are in the axial direction. They are superimposed on each other over their entire length. Note that the mesh-like skeleton structure may be composed of two wires 130a and 130b extending in opposite directions in the circumferential direction as in the ninth embodiment, and is also shown in FIGS. 41 to 43. As described above, it can also be configured by connecting the crests of annular struts extending in the circumferential direction while being folded back in the axial direction to each other in the axial direction.

In the present embodiment, the mesh interval (distance between the annular struts adjacent in the axial direction) in the first skeleton structure 146 and the mesh interval in the second skeleton structure 148 are made equal to each other. The phases of these meshes are shifted from each other.

By superposing the first skeleton structure 146 and the second skeleton structure 148 on each other, the struts constituting the second skeleton structure 148 are positioned on the first gap 150 in the radial direction of the stent 144. At the same time, since the struts constituting the first skeleton structure 146 are positioned on the second gap 152, the first and second gaps 150 and 152 can be made smaller than a single state.

In the present embodiment, the first and second skeleton structures 146 and 148 are separately formed by electroforming. By forming the first and second skeletal structures 146 and 148 by electroforming, the stent 144 can be made thinner in thickness in the radial direction than a normal stent. The radial thickness dimension of the stent 144 is preferably 30 to 300 μm, more preferably 100 μm or less. Then, the second skeleton structure 148 is overlapped on the outer peripheral side of the first skeleton structure 146, and both the skeleton structures 146 and 148 are fixed to each other in an inseparable manner by means such as adhesion or welding. The stent 144 of the embodiment is configured. In addition, the manufacturing method of the first and second skeleton structures 146 and 148 is not limited in any way. For example, one of the first and second skeleton structures 146 and 148 is formed by electroforming, The other may be formed by a method other than electroforming. In addition, the stent 144 may be formed by electroforming with a shape in which the skeleton structures 146 and 148 are integrally overlapped.

Also in the stent 144 of this embodiment having the above-described structure, the gaps 150 and 152 are reduced by overlapping the first skeleton structure 146 and the second skeleton structure 148. The same effect as in the ninth embodiment can be exhibited.

In particular, when a stent having a shape in which two mesh-like skeleton structures are overlapped is placed, for example, the first stent is first placed in the lumen, and then the second stent is placed on the inner peripheral side of the first stent. When the first stent and the second stent are placed in an overlapping state, the skeleton structure of the first stent and the skeleton structure of the second stent are overlapped with each other, so that the gap between them is not reduced. May not be prevented. However, like the stent 144 of the present embodiment, the first and second skeletal structures 146 and 148 are overlapped with each other and integrated so as not to be separated, so that the first and second gaps can be formed before the stent is placed. 150 and 152 are reliably reduced. Thereby, the re-projection of the plaque and the restenosis of the lumen can be prevented more stably.

In addition, a stent having such a mesh-like skeleton structure generally has a small diameter of wires and struts, and the stent strength may be insufficient. However, the skeleton structures are integrated in a state where two skeleton structures are overlapped in the radial direction. Thus, the stent strength can be improved. Furthermore, rather than simply forming a stent with a small gap, the gap is reduced by overlapping two skeleton structures, and the possibility of greatly impairing the flexibility of the stent is also avoided.

In addition, the manufacturing method of the first and second skeleton structures 146 and 148 as described above is not limited in any way, and any of them can be manufactured by a conventionally known method, but these are manufactured by electroforming. It is not necessary to carry out the end processing operation, and the manufacturing efficiency can be improved.

Next, FIG. 44 shows a stent 154 as a twelfth embodiment of the present invention. The stent 154 of the present embodiment is configured by superimposing a second skeleton structure 158 whose phase is shifted with respect to the first skeleton structure 156 on the outer peripheral side of the first skeleton structure 156 shown in FIG. Has been. Each of the first and second skeleton structures 156 and 158 spirals in the circumferential direction while one linear body is folded back in the axial direction, like the second skeleton structure 128 in the ninth embodiment. It is made into the coil shape extended in a shape, and is made into the repeating structure which a substantially single structure (cell) continues in the circumferential direction and an axial direction.

Also in the stent 154 having such a structure, the gap in the first skeleton structure 156 and the gap in the second skeleton structure 158 are larger than those in the case where the first skeleton structure 156 and the second skeleton structure 158 are single, respectively. Since the two skeletal structures 156 and 158 are overlapped, the same effect as that of the stent 124 described in the ninth embodiment can be exhibited.

Next, FIG. 46 shows a stent 160 as a thirteenth embodiment of the present invention. The stent 160 is a stent that is placed in a branch portion of a lumen. The main stent 162 that is placed in the trunk portion of the lumen, and a side branch stent 164 that is placed in a side branch portion of the lumen. It is configured to include. The main stent 162 and the side branch stent 164 in this embodiment have the same structure as the stent 124 in the ninth embodiment. In FIG. 46, the side branch side is the upper right side in FIG. 46, while the main side is the lower left side in FIG. In FIG. 46, the axial direction of the stent 160 refers to a linear direction connecting the lower left and upper right in FIG.

The main stent 162 and the side branch stent 164 are connected to each other by a connecting strut 166 and are continuous. Specifically, the end of the main stent 162 and the end of the side branch stent 164 are integrally connected in the axial direction by a connecting strut 166. As a result, the linear body constituting the main stent 162 and the linear body constituting the side branch side stent 164 are connected, and the entire stent 160 is formed by a continuous linear body. . That is, the main side stent 162 and the side branch side stent 164 are integrated.

In the initial state shown in FIG. 46, the connecting strut 166 in the present embodiment is a portion extending in a straight line in the axial direction, and the main stent 162 is bent or bent by bending the connecting strut 166. The side branch side stent 164 can be extended in different directions. As a result, the main stent 162 can be inserted into the main branch at the branch portion of the lumen, while the side branch stent 164 can be inserted into the side branch of the lumen.

Also in the stent 160 of the present embodiment configured as described above, the same structure as that of the stent 124 of the ninth embodiment is adopted as the main stent 162 and the side branch stent 164. The same effect as in the ninth embodiment can be exhibited.

By the way, conventionally, when placing a stent in the branch portion of the lumen, first, the first stent is placed in the main trunk portion of the lumen and then the hole opened in the peripheral wall of the first stent. The second stent was placed in the side branch of the lumen through the part, but itching and turbulence such as blood flow occurred in the overlapping part of the first stent and the second stent. There was a risk of blood clots and the like causing restenosis.

On the other hand, in the stent 160 of the present embodiment, a connecting strut 166 is provided at an intermediate portion in the axial direction of one stent, and the connecting strut 166 bends or curves so that the stent is separated from the branched lumen. 160 may be deployed. That is, when the stent 160 is indwelled in the branched lumen, since there is no overlapping portion between the main stent 162 and the side branch stent 164, it is possible to suppress stagnation and turbulence of blood and the like, The risk of restenosis can be further reduced.

In addition, it is preferable that the stent 160 of this embodiment is integrally formed by electroforming. For example, JP-T-2009-508622 discloses a stent in which a stent placed on the main trunk side of the lumen and a stent placed on the side branch side of the lumen are connected to each other by welding. . However, in the stent described in the above publication, there is a possibility that the bending strength is insufficient because the portions that are bent or curved corresponding to the branching of the lumen are connected by welding. On the other hand, in the stent 160 of this embodiment, the connecting strut 166 is integrally formed with the main stent 162 and the side branch stent 164, so that the bending strength of the connecting strut 166 when bent or bent is increased. Improvement can be achieved. In particular, by forming the stent 160 by electroforming, the material of the connecting strut 166 can be changed from that of the main stent 162 and the side branch stent 164. Therefore, it is possible to adopt a material that is more easily bent or curved. Thus, the degree of design freedom can be improved.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited by the specific descriptions, and is implemented in a mode in which various changes, corrections, improvements, and the like are added based on the knowledge of those skilled in the art. Any of such embodiments can be included in the scope of the present invention without departing from the spirit of the present invention.

For example, in the above-described embodiment, the coiled skeleton structure is a structure in which one linear body is spirally extended in the circumferential direction while being folded back in the axial direction, but is not limited to such a mode. That is, a structure in which a single linear body is folded in the axial direction and extends annularly in the circumferential direction as a coiled skeleton structure, and a plurality of annular bodies are connected by a link portion in the axial direction May be adopted.

Furthermore, in the ninth to twelfth embodiments, the first skeleton structure 126, 146, 156 and the second skeleton structure 128, 148, 158 have substantially the same axial dimensions, and these are the axial dimensions. Although it overlap | superposed over substantially full length, it is not limited to this aspect. In other words, the first skeleton structure and the second skeleton structure only need to partially overlap each other in the axial direction, and in the overlapping portion, the first gap or It is sufficient that the second gap is small.

In the ninth, eleventh, and twelfth embodiments, the second skeleton structures 128, 148, and 158 are located on the outer peripheral side of the first skeleton structures 126, 146, and 156. The second skeleton structure may be located on the inner peripheral side of the skeleton structure.

Further, in the eleventh and twelfth embodiments, in the first skeleton structures 146 and 156 and the second skeleton structures 148 and 158, the sizes of the first gap and the second gap are made equal to each other. The phases of these skeleton structures are made different from each other, so that the gap is reduced in a state where the respective skeleton structures are overlapped, but this is not a limitation. That is, by adopting the first skeleton structure and the second skeleton structure having the same gap size and phase and superposing them by shifting in the axial direction, the first gap Alternatively, the second gap may be reduced.

Alternatively, as in the stent 168 shown in FIG. 47, the first skeleton structure and the second skeleton structure having different gap sizes may be superimposed. That is, in the stent 168 shown in FIG. 47, the first skeleton structure 170 shown in FIG. 48 and the second skeleton structure 172 shown in FIG. Is made up of. In particular, in this aspect, the first gap 174 in the first skeleton structure 170 located on the inner peripheral side is made smaller than the second gap 176 in the second skeleton structure 172 located on the outer peripheral side. ing.

As in this aspect, the first gap 174 and the second gap 176 are different in size, so that both the skeletal structures 170 and 172 can have both the axial position and the circumferential position. By superimposing the skeleton structures 170 and 172, the first or second gaps 174 and 176 can be made smaller than those in a single state.

In particular, by making the first gap 174 in the first skeleton structure 170 located on the inner circumference side smaller than the second gap 176 in the second skeleton structure 172, the inner circumference of the stent 168 is changed to the outer circumference. On the other hand, the outer peripheral surface of the stent 168 may have a larger unevenness than the inner peripheral surface. As a result, it is possible to suppress stagnation and turbulence such as blood flow, prevent thrombus formation and lumen restenosis, and stabilize the positioning effect in the lumen by the convex portion of the outer peripheral surface of the stent. Can be demonstrated.

In the aspect shown in FIG. 47, the first skeleton structure 170 and the second skeleton structure 172 have mesh shapes, and the sizes of the gaps in the mesh shapes are different. Is not to be done. That is, each of the first skeleton structure and the second skeleton structure is formed into a coil shape that spirals in the circumferential direction while being folded back in the axial direction as in the twelfth embodiment. By adopting skeleton structures having different sizes of the first and second gaps, the first gap and the second gap when the first skeleton structure and the second skeleton structure are overlaid. Each may be smaller than a single state. Even in such a case, the gap in the first skeletal structure located on the inner circumferential side is made smaller than the gap in the second skeletal structure located on the outer circumferential side. The effect of preventing restenosis and the effect of positioning in the lumen can be exhibited.

Furthermore, in the thirteenth embodiment, the connecting strut 166 is composed of a single linear portion that connects the end of the main stent 162 and the end of the side branch stent 164. The connecting strut may be configured with a plurality of linear portions. In such a case, it is preferable that the connecting struts are provided close to each other, for example, adjacent to each other in the circumferential direction in a part of the circumference, thereby maintaining flexibility in the bending direction of the connecting struts. , The strength can be improved.

In the thirteenth embodiment, the connecting strut 166 extends linearly in the axial direction in the initial state. However, the connecting strut 166 may be bent or curved with respect to the axial direction. The shape of is not limited at all.

Furthermore, in the thirteenth embodiment, the connecting strut 166 is integrally formed with the linear body 134 constituting the second skeletal structure 128, but an appropriate portion of the linear body 134 is pivoted. You may be comprised by the connection part 136 linked and reinforced in the direction.

Further, in the above embodiment, the stents 124, 140, 160 in the ninth, tenth, and thirteenth embodiments and the first and second skeleton structures in the modes shown in the eleventh, twelfth embodiments, and FIG. Although 146, 148, 156, 158, 170, and 172 are formed by electroforming, etching may be employed instead of electroforming or in combination with electroforming. Note that when the first skeleton structure and the second skeleton structure are formed separately, one may be formed by electroforming or etching, and the other may be formed by a method other than electroforming or etching.

Furthermore, in the above-described embodiment, the two skeleton structures are formed to overlap each other. However, three or more skeleton structures may be overlapped to each other. In such a case, any skeleton structure may be the first skeleton structure or the second skeleton structure, and the first skeleton structure and the second skeleton structure are overlapped to form the first skeleton structure. It is sufficient that the gap or the second gap is reduced.

When a plurality of the first gaps in the first skeleton structure and the second gaps in the second skeleton structure are formed, it is not necessary to reduce all of the gaps. Compared with the case where the skeleton structure is present alone, at least one gap in the first or second gap may be reduced.

Here, in the thirteenth embodiment, the aspect in which the first skeleton structure 126, 126 is not provided, that is, the stent 178 shown in FIGS. 50 to 54 and the stent 180 shown in FIG. It can be recognized as an independent invention that can solve different problems.

The stent 178 shown in FIGS. 50 to 54 is a stent placed in the branch portion of the lumen. The main stent 182 placed in the trunk portion of the lumen and the side branch portion of the lumen are placed. Side branch side stents 184 are integrally formed continuously with each other via connecting struts 186.

In this embodiment, it is preferable to reduce the outer diameter of the side branch side stent 184 relative to the outer diameter of the main side stent 182 corresponding to the diameter size of the main trunk portion and the side branch portion of the lumen. Therefore, it is preferable to set the circumferential wave pitch of the main stent 182 to be smaller than that of the side branch stent 184, as shown in the developed view of FIG.

The stent 178 can be formed by a conventionally known method such as electroforming or laser cutting, but it is preferable that the stent 178 be formed by electroforming because the degree of design freedom of the thickness dimension and material can be improved. . Etching may be employed instead of electroforming or in combination with electroforming. In the stent 178, one of the main stent 182 and the side branch stent 184 may be formed by electroforming. For example, the connecting strut is connected to the end of the main stent formed by a method other than electroforming. And the side branch side stent may be integrally formed.

55, the main stent 188 and the side branch stent 190 are placed in a state where the main stent 188 and the side branch stent 190 are arranged on a straight line extending in the same direction. May overlap each other in the length direction. The stent 180 in FIG. 55 is shown in a state where it is indwelled at the branch portion of the lumen, that is, in a state where the connecting strut 186 is bent with respect to the axial direction, while the main stent 188 and the side branch side are shown. A state in which the stent 190 is arranged on a straight line extending in the same direction is indicated by a two-dot chain line.

Here, at the end on the side branch side stent 190 side of the linear body constituting the skeleton structure of the trunk side stent 188, the axial dimension is enlarged at a part of the circumference. Thus, the main stent 188 and the side branch stent 190 are in the length direction (left and right direction in FIG. 55) in a state where the main stent 188 and the side branch stent 190 are arranged on a straight line extending in the same direction. Are overlapping each other.

In this way, the end portion of the main stent 188 extends in the side branch side stent 190 side rather than the end portion of the side branch side stent 190 at a part of the circumference. The stent can be placed so as to cover more widely, and treatment for a wider area within the lumen is possible.

That is, the first aspect of the present invention is a stent placed in a branch portion of a body lumen, and a trunk side skeleton structure constituting the trunk side stent placed in the trunk portion of the body lumen; The side branch side skeleton structure constituting the side branch side stent placed in the side branch portion of the body lumen is formed of a coiled strut extending continuously in the circumferential direction while being folded back in the axial direction, and the trunk side A connecting strut extending across the ends of the stent and the side branch side stent is formed continuously with each of the coiled struts constituting the main side stent and the side branch side stent, or the main trunk. The main stent and the side branch stent are integrated with each other by providing a connection link for connecting the side stent and the coiled struts constituting the side branch side stent. It is an.

According to a second aspect, in the stent according to the first aspect, a wave pitch in the trunk side skeleton structure of the trunk side stent is smaller than a wave pitch in the side branch side skeleton structure of the side branch side stent. It is what has been.

According to a third aspect, in the stent according to the first or second aspect, the peripheral walls on the open end sides of the trunk side stent and the side branch side stent facing each other are the main side stent and the side branch side. The stents are overlapped with each other in a state where they are arranged on a straight line extending in the same direction.

According to a fourth aspect, in the stent according to any one of the first to third aspects, at least one of the main stent and the side branch side stent is integrated with each other by electroforming or etching. Is formed.

Also, the stent according to the embodiment shown in FIGS. 38 to 49 and the embodiment shown in FIGS. 50 to 55 may be formed of a laminated structure of a plurality of types of metals. For example, by using a metal material with a lower ionization tendency in the inner layer than in the outer layer, the force to hold the lumen against the recoil of the blood vessel when the balloon is expanded is strong, and the skeleton becomes thinner with time. Thus, it is possible to improve the followability. For example, the outer layer may be formed of magnesium or iron, and the inner layer may be formed of nickel titanium alloy or cobalt. In this aspect, it is only necessary that at least a part of the length direction or the circumferential direction of the stent has a laminated structure of a plurality of types of metals, and the entire stent needs to have a laminated structure of a plurality of types of metals. Absent.

Further, the stent according to the embodiment shown in FIGS. 38 to 49 and the aspect shown in FIGS. 50 to 55 includes a Y-shaped branched shape, a tapered shape, and a thick end shape, as well as a basic cylindrical portion. Stents with different diameters of the branch cylinders, stents in which at least one of the trunk cylinder part and the branch cylinder part is a tapered cylinder, a stent partially tapered in the length direction, and the length direction Applicable to various types of deformed stents, such as stents with thick parts at the end and center, stent bodies excluding covered stent covers, and bent or bent stents in the middle in the longitudinal direction. is there. The stent bent or bent at the intermediate portion in the longitudinal direction is effective for a highly curved or bent portion of a patient having advanced arteriosclerosis.

Furthermore, the stent according to the embodiment shown in FIGS. 38 to 49 and the aspect shown in FIGS. 50 to 55 is formed by thermal spraying or vacuum deposition, which is known as a molding technique such as film formation, like electroforming. It may be formed. For example, a stent is formed by integrating a large number of sprayed particles of a material that has been melted or brought close to it into a predetermined shape by heating, or a large number of particles of a material that has been vaporized or sublimated by being heated to a predetermined shape. It is also possible to form a stent by integrating them with each other.

Also, the stent structured according to the embodiment shown in FIGS. 38 to 49 and the aspect shown in FIGS. 50 to 55 is also applied to a flow diverter for treating cerebral aneurysms. The flow diverter is, for example, a low-porosity blood flow bypass device improved for endovascular treatment of cerebral aneurysms. Furthermore, the stent structured according to the embodiment shown in FIGS. 38-49 and the aspects shown in FIGS. 50-55 is also applicable to the tip portion in a stent retriever system. The stent retriever system is, for example, a reticular cylindrical thrombectomy device for efficiently squeezing and removing a thrombus with a net. *

FIG. 56 (a) shows a stent 192 as a fourteenth embodiment of the present invention in a molded state that is neither expanded nor contracted. As shown in FIG. 56 (b), the stent 192 is attached in a state of being reduced in diameter to a balloon 196 externally attached to the distal end portion of the catheter 194, and the distal end portion of the catheter 194 is attached to the body lumen. Is inserted into the stenosis. Then, by expanding the balloon 196 at the stenosis portion, the diameter of the stent 192 is expanded and bites into the lumen wall, and the stenosis portion is expanded and placed in the lumen. In the following description, the axial direction refers to the left-right direction in FIG. 56, which is the direction in which the stent 192 extends. Further, the distal end side refers to the left side in FIG. 56 that is the forward direction of the catheter 194, while the proximal end side refers to the right side in FIG. 56 that is the side on which the user operates the catheter 194.

More specifically, the stent 192 has a substantially cylindrical shape as a whole and linearly extends, and includes a plurality of annular portions 198 provided at a predetermined distance in the axial direction. Each of the annular portions 198 is formed by continuously extending one linear body 200 in an annular shape in the circumferential direction while turning back in the axial direction.

And the annular part 198,198 adjacent in an axial direction is mutually connected by the link part 202 extended in a substantially axial direction in the several places on the circumference, The stent 192 made into the cylindrical shape of predetermined length is carried out. Is formed. That is, each annular portion 198 constitutes a strut 204 that is a peripheral wall of the stent 192, and a predetermined position in the strut 204 is connected by the link portion 202. The specific shapes of the annular portion 198 and the link portion 202 are not limited in the present invention, and considering the characteristics required for the stent 192, the wave shape of the strut 204 and the connecting portion by the link portion 202 are not limited. The number of link portions 202 on the circumference of the annular portion 198 can be appropriately set.

The stent 192 having such a shape is reduced in diameter and attached to the catheter 194, whereby the stent 192 is delivered to the stenosis portion of the lumen. Specifically, a balloon 196 is extrapolated to the distal end of the catheter 194, and the balloon 196 is folded in an initial state. Then, the reduced diameter stent 192 is mounted on the folded balloon 196. The stent 192 is attached to the balloon 196 by, for example, inserting the catheter 194 including the balloon 196 into the molded stent 192 shown in FIG. Is realized. In the present invention, the structures of the catheter 194 and the balloon 196 are not limited in any way, and are indicated by phantom lines in FIG. 56 (b).

Here, FIG. 57A shows a longitudinal section of the strut 204 when the stent 192 is attached to the balloon 196. As shown in FIG. 57 (a), the vertical cross-sectional shape of the strut 204 (linear body 200) is a substantially rounded quadrilateral as a whole, and the upper side of the vertical cross-section in FIG. On the other hand, the lower side is the inner peripheral surface 208. In FIG. 57, the left side is the distal end side, and the right side is the proximal end side.

And, from the inner peripheral surface 208 of the strut 204, a balloon linking protrusion 210 as an inner peripheral linking protrusion is integrally formed. The balloon linkage protrusion 210 of the present embodiment has a protruding piece shape that protrudes from the inner peripheral surface 208 of the strut 204, and extends inclining from the distal end side toward the proximal end side. Thereby, the inner surface 212 of the balloon linkage protrusion 210 (the upper surface in FIG. 57 in the balloon linkage protrusion 210) is opposed to the inner peripheral surface 208 of the strut 204 with a predetermined separation distance. Further, the protruding length dimension of the balloon linkage protrusion 210 is made smaller than the width dimension of the strut 204 (the horizontal dimension in FIG. 57). The balloon linkage protrusion 210 may be provided over the entire length of the strut 204, but in this embodiment, it is provided partially in the length direction of the strut 204, and the strut 204 is viewed in the thickness direction ( For example, in FIG. 57, when the strut 204 is viewed from above, the balloon linkage protrusion 210 has a substantially rectangular shape. Thereby, the deformation | transformation of the balloon connection protrusion 210 mentioned later is implement | achieved easily.

In addition, in the mounted state on the balloon 196, the outer surface 214 of the balloon linking projection 210 slightly bites into the outer peripheral surface of the balloon 196. Accordingly, in the present embodiment, the balloon linking projection 210 is locked by acting in conjunction with the balloon 196 in a state where the stent 192 is attached to the balloon 196.

The stent 192 attached to the catheter 194 as described above is delivered to the stenosis of the lumen and the balloon 196 is expanded, so that the strut 204 bites into the lumen wall 216 as shown in FIG. In this way, the stent 192 is placed in the lumen.

Here, as the balloon 196 is expanded, the balloon linking protrusion 210 protruding from the inner peripheral surface 208 of the strut 204 is pressed from the inner peripheral side, whereby the inner peripheral surface 208 of the strut 204 and the balloon linking protrusion are pressed. The balloon linkage protrusion 210 is plastically deformed so that the inner surface 212 of the 210 is overlapped. Since the protruding length dimension of the balloon linkage protrusion 210 is smaller than the width dimension of the strut 204, the balloon linkage protrusion 210 does not protrude from the strut 204 when deformed. Thereby, after the deformation | transformation of the balloon linkage protrusion 210, the unevenness | corrugation on the surface of the strut 204 can be restrained small.

In the stent 192 of the present embodiment, the strut 204 and the balloon linkage protrusion 210 can be integrally formed by electroforming, for example. That is, for example, the integral shape of the strut 204 and the balloon linking protrusion 210 as described above may be formed by one-time electroforming, or the inner peripheral surface of the strut 204 of the stent in which the balloon linking protrusion 210 is not provided. The strut 204 and the balloon linking projection 210 may be integrally formed by appropriately performing masking on 208 and performing electroforming. However, a stent not provided with such a balloon linkage protrusion 210 does not need to be formed by electroforming, and can be manufactured by a conventionally known manufacturing method. The material of the stent 192 is not limited in any way, but can be suitably formed from, for example, a nickel titanium alloy or stainless steel.

In the stent 192 of the present embodiment having the above-described structure, the balloon linking projection 210 is locked to the outer peripheral surface of the balloon 196 in the mounted state on the balloon 196. Also when inserted into the balloon 196, the balloon linking projection 210 is caught by the balloon 196, and the drop of the stent 192 from the balloon 196 is effectively prevented.

In particular, since the balloon linkage projection 210 is locked so as to bite into the outer peripheral surface of the balloon 196 and the holding force on the balloon 196 is improved, a balloon linkage projection having a conventional structure is provided. The stent 192 can be attached to the balloon 196 with less caulking force compared to a stent that is not. Thereby, the stent 192 when the balloon 196 is attached can be made more flexible, and the follow-up deformation of the distal end portion of the catheter 194 with respect to the bent lumen can be further facilitated.

Further, when the catheter 194 with the stent 192 attached is inserted into the lumen, the lumen wall 216 and the outer peripheral surface 206 of the strut 204 come into contact with each other, so that the catheter 194 advances in the stent 192 (FIG. 57). An external force is applied that shifts in the opposite direction from the middle right to the left). On the other hand, since the balloon linkage protrusion 210 protrudes in the same direction as the direction in which the deviation external force is exerted, the tip of the balloon linkage projection 210 is caught on the outer peripheral surface of the balloon 196, and the hook is displaced against the deviation external force. It will act as a resistance. Thereby, the position shift and dropping of the stent 192 in the axial direction on the balloon 196 can be more effectively prevented.

Further, in this embodiment, the balloon linking protrusion 210 protruding from the inner peripheral surface 208 of the strut 204 is plastically deformed as the balloon 196 is expanded, and the inner peripheral surface 208 of the strut 204 and the balloon linking protrusion 210 are deformed. The inner surface 212 is in contact with the inner surface 212. Thereby, when the balloon 196 is expanded, the expansion force of the balloon 196 is stably transmitted to the outer peripheral side of the strut 204, and the stent 192 can be easily placed in the lumen. Furthermore, the deformation of the balloon linkage protrusion 210 suppresses the protrusion of the strut 204 from the inner peripheral surface 208, so that the inner peripheral surface of the stent 192 has a smooth shape with less irregularities. This effectively prevents thrombus generation due to stagnation or turbulence of blood or the like passing through the inside of the stent 192 and restenosis due to adhesion of the thrombus to the inner peripheral surface of the stent 192.

Furthermore, in the present embodiment, since the stent 192 is formed by electroforming, it can be manufactured even in a shape that is difficult to manufacture by laser cutting or the like. Further, for example, the material of the balloon linking protrusion 210 that deforms in the stent 192 can be different from that of the strut 204, and the strut 204 is formed of a material having high hardness, while the balloon linking protrusion 210 is made of a material that is easily deformed. For example, the degree of freedom in design can be improved.

Next, FIG. 58 shows a longitudinal section of the strut 220 in the stent 218 as the fifteenth embodiment of the present invention. On the outer peripheral side surface 206 of the strut 220 of the present embodiment, a medicine containing recess 222 for containing a medicine is formed to open to the outer peripheral side, while from the outer peripheral side surface 206 of the strut 220, an outer peripheral linkage protrusion. A balloon linking projection 224 as a part is formed to project. In the following description, the overall view of the stent 218, the front view showing the state of attachment to the balloon 196, and the like are the same as those in the fourteenth embodiment, and the illustration is omitted. The members and portions that are substantially the same as those in the fourteenth embodiment are denoted by the same reference numerals as those in the fourteenth embodiment in the drawing, and detailed description thereof is omitted.

The balloon linkage protrusion 224 has a protruding piece shape protruding from the outer peripheral surface 206 of the strut 220, and is inclined from the distal end side toward the proximal end side. That is, in the mounting state on the balloon 196 shown in FIG. 58 (a), the inner surface 226 of the medicine housing recess 222 and the inner surface 228 of the balloon linkage protrusion 224 are opposed to each other with a predetermined separation distance. And a medicine (gray part in Drawing 58 (a)) is stored between the opposing surfaces of these both sides 226 and 228. The drug accommodated in the drug accommodating recess 222 is not limited in any way. For example, a drug having a cell growth inhibitory effect is accommodated to prevent luminal restenosis. The drug is preferably in the form of a gel, but a capsule encapsulating the drug, biodegradable resin cotton impregnated with the drug, or the like may be disposed in the drug containing recess 222. For example, a bag-like body enclosing a drug solution is installed in the medicine housing recess 222, and needle-like projections are formed on the inner surface 228 of the balloon linking projection 224 so that the balloon linking projection 224 moves toward the medicine housing recess 222. By deforming so as to fall down, the needle-like projections can break through the bag-like body to release the chemical solution.

In addition, although the medicine accommodating recess 222 may be provided over the entire length of the strut 220, in the present embodiment, the strut 220 is formed with a substantially rectangular cross section when viewed in the thickness direction and with a predetermined depth dimension. On the other hand, a protruding piece-like balloon linking protrusion 224 is formed at a position corresponding to the medicine receiving recess 222. In addition, the shape of the inner surface 226 of the medicine housing recess 222 and the shape of the inner surface 228 of the balloon linking projection 224 are made to correspond to each other. In particular, in this embodiment, since the proximal end portion of the balloon linkage protrusion 224 protrudes in a state where it partially enters the medicine receiving recess 222, the side of the unintended balloon linkage protrusion 224, etc. In addition, the balloon linkage projection 224 can be deformed so as to smoothly enter the medicine housing recess 222 when the balloon linkage projection 224 is deformed when the diameter is increased. The

When the stent 218 having the above-described shape is delivered to the narrowed portion of the lumen and the balloon 196 is expanded, as shown in FIG. The balloon linking projection 224 is deformed so as to enter the medicine receiving recess 222 by being pressed to the inner peripheral side by the wall 216. Thereby, the volume in the medicine housing recess 222 is reduced, and the medicine is discharged to the outside (in the lumen wall 216).

Further, in this embodiment, since the shape of the inner surface 226 of the medicine housing recess 222 and the shape of the inner surface 228 of the balloon linking projection 224 are mutually corresponding, the balloon linking projection 224 has the medicine housing dent. The volume of the drug containing recess 222 is sufficiently reduced by fitting into the location 222 and overlapping in a substantially close state. Further, the balloon linkage protrusion 224 enters the medicine receiving recess 222, so that the outer surface 230 of the balloon linkage projection 224 is positioned on the same plane as the outer peripheral surface 206 of the strut 220. Unevenness on the surface of the subsequent strut 220 is reduced.

In the stent 218 of the present embodiment configured as described above, the balloon linking protrusion 224 enters the drug containing recess 222 as the balloon 196 is expanded. Unlike conventional stents such as those described above, drugs are actively discharged. Thereby, a more reliable drug release effect can be exhibited.

In particular, in this embodiment, since the balloon linking protrusion 224 enters the drug containing recess 222 and overlaps the inner surface of the drug containing recess 222 in a close manner, Drug residues can be prevented as much as possible.

Further, as in the longitudinal section of the strut 234 in the stent 232 according to the sixteenth embodiment of the present invention shown in FIG. 59, the strut 234 has a hollow structure, and its internal space is slightly more than the outer peripheral surface of the strut 234. A small medicine receiving recess 236 may be provided. An opening 238 is provided in a specific portion on the outer periphery of the strut 234, and the medicine housing recess 236 is opened on the outer peripheral surface 206 of the strut 234 through the opening 238.

In addition, the strut 234 of this embodiment has a cross-sectional shape of a rhombus frame as a whole, and one corner of the rhombus is located on the inner peripheral side. That is, the strut 234 of the present embodiment includes a pair of first peripheral wall portions 240 and 240 located on the inner peripheral side and a pair of second peripheral wall portions 242 and 242 located on the outer peripheral side. The one peripheral wall portions 240 and 240 are connected to each other at the inner peripheral side end portion, and extend from the inner peripheral side end portion to the outer peripheral side, respectively, and extend to the distal end side and the proximal end side, respectively. Then, a pair of second peripheral wall portions 242 and 242 extend from the distal end side end portion and the proximal end side end portion of the first peripheral wall portions 240 and 240, and inward in the axial direction toward the outer peripheral side. It extends. Therefore, a predetermined separation distance is provided between the first peripheral wall portions 240 and 240 and the second peripheral wall portions 242 and 242 in the thickness direction of the strut 234 (vertical direction in FIG. 59). A region surrounded by the first and second peripheral wall portions 240, 240, 242, and 242 is a drug containing recess 236.

In such a stent 232 of this embodiment, on the inner peripheral surface 208 of the strut 234, the protruding portion that protrudes toward the inner peripheral side and slightly bites into the outer peripheral surface of the balloon 196 at the connection portion of the first peripheral wall portions 240 and 240. These protrusions can be regarded as balloon linkage protrusions 244 as inner circumference linkage protrusions that lock the stent 232 to the balloon 196. Or in the stent 232 of this embodiment, a pair of 1st surrounding wall part 240,240 can be understood as a strut, and it is each axial direction from the outer peripheral side edge part of these each 1st surrounding wall part 240,240, respectively. Each of the second peripheral wall portions 242 and 242 that incline at a predetermined angle and protrude toward the outer peripheral side can be regarded as a balloon linkage protrusion. That is, each of the second peripheral wall portions 242 and 242 serving as the balloon linking protrusions has a chemical solution containing recess formed from the outer peripheral side formed between the first peripheral wall portions 240 and 240 serving as the struts. It is provided so as to cover, and when expanding the stent, it is deformed toward the first peripheral wall portions 240 and 240 as struts so as to fall toward the chemical solution containing recess with a small inclination angle. It becomes.

By delivering the stent 232 having the above-described shape to the stenosis of the lumen and expanding the balloon 196, the strut 234 is deformed as shown in FIG. Since the facing distance between the portions 240 and 240 and the second peripheral wall portions 242 and 242 is reduced, the volume of the medicine containing recess 236 is reduced. In other words, the second peripheral wall portions 242 and 242 enter the medicine containing recess 236, and the volume of the medicine containing recess 236 reduces the volume of the medicine through the opening 238 (lumen wall 216). Middle). Therefore, in this embodiment, each of the second peripheral wall portions 242 and 242 constitutes a balloon linking protrusion, and these balloon linking protrusions are positioned on the outer peripheral side of the strut 234 so that the balloon 196 It is the outer peripheral linkage protrusion that discharges the drug with expansion deformation.

Also in the stent 232 of the present embodiment, the volume of the drug containing recess 236 decreases with the expansion of the balloon 196, and the drug is released into the lumen wall 216, so that the same as in the fifteenth embodiment. The effect can be exhibited. In addition, since the stent 232 is locked to the balloon 196 by the balloon linkage projection 244 as the inner circumference linkage projection, the same effect as in the fourteenth embodiment can be exhibited. Therefore, by adopting the shape of the strut 234 in the present embodiment, it is possible to achieve both the effect of preventing the stent 232 from falling off the balloon 196 and the more reliable drug release effect.

Next, FIG. 60 shows a longitudinal section of the strut 248 in the stent 246 as the seventeenth embodiment of the present invention. In this embodiment, the medicine housing recess 250 is formed so as to penetrate in the thickness direction of the strut 248. Further, as shown in the attached state of the stent 246 to the balloon 196 in FIG. 60 (a), the balloon linkage protrusion 252 similar to that of the fourteenth embodiment extends from the inner peripheral surface 208 of the strut 248. The outer surface 214 of the balloon linking projection 252 slightly bites into the outer peripheral surface of the balloon 196, and the balloon linking projection 252 is locked to the balloon 196. On the other hand, an extrusion protrusion 254 that extends inward of the strut 248 is provided on the inner surface 212 of the balloon linkage protrusion 252. The extrusion protrusion 254 is a substantially rectangular parallelepiped block as a whole, and is formed integrally with the balloon linkage protrusion 252. As shown in FIG. 60 (a), a part of the extrusion protrusion 254 may enter the medicine containing recess 250 even before the balloon 196 is expanded, or substantially the whole of the pushing protrusion 254 may be the medicine containing recess. It may be located outside the location 250.

In the stent 246 of this embodiment having such a structure, as shown in FIG. 60B, when the balloon 196 is expanded, the balloon linking protrusion 252 becomes the balloon 196 as in the fourteenth embodiment. The inner surface 208 of the strut 248 and the inner surface 212 of the balloon linkage projection 252 are overlapped with each other. Thereby, substantially the whole extrusion protrusion 254 enters the medicine containing recess 250 from the inner peripheral side. As a result, as the balloon 196 is expanded, the volume of the drug receiving recess 250 decreases, and the drug is released into the lumen wall 216. In particular, in this embodiment, the extrusion protrusion 254 is formed so as to extend from the inner peripheral side to the outer peripheral side, and the medicine in the medicine containing recess 250 is pushed out from the inner peripheral side to the outer peripheral side. Therefore, the trouble that the medicine remains in the bottom of the medicine housing recess 250 can be prevented more effectively. Therefore, in this embodiment, the balloon linkage projection 252 having the extrusion projection 254 constitutes the extrusion unit.

In the present embodiment, the protrusion dimension of the extrusion protrusion 254 from the balloon linkage protrusion 252 is substantially equal to the thickness dimension of the strut 248 (the vertical dimension in FIG. 60), as shown in FIG. 60 (b). In the expanded state of the balloon 196, the protruding distal end surface 256 of the extrusion protrusion 254 and the outer peripheral surface 206 of the strut 248 are located on substantially the same plane, but the present invention is not limited to this mode. That is, the protrusion dimension of the extrusion protrusion 254 may be smaller than the thickness dimension of the strut 248, and the protrusion front end surface 256 of the extrusion protrusion 254 may be positioned inside the drug containing recess 250 in the expanded state of the balloon 196. In addition, the protruding dimension of the extrusion protrusion 254 may be larger than the thickness dimension of the strut 248, and the protruding front end surface 256 of the extrusion protrusion 254 may protrude from the outer peripheral surface 206 of the strut 248 in the expanded state of the balloon 196. In the expanded state of the balloon 196, when the protruding distal end surface 256 of the extrusion protrusion 254 protrudes from the outer peripheral surface 206 of the strut 248, not only the outer peripheral surface 206 of the strut 248 but also the distal end portion of the extrusion protrusion 254 is the lumen wall 216. Therefore, the positioning effect of the stent 246 at the time of placement in the lumen can be exhibited to a higher degree.

Also in the stent 246 in the present embodiment, the volume of the drug containing recess 250 decreases as the balloon 196 expands, and the drug is released into the lumen wall 216. Therefore, the stent 218 in the fifteenth embodiment A similar drug release effect can be exerted. Further, since a balloon linkage projection 252 as an inner circumference linkage projection to be locked to the balloon 196 is provided as in the fourteenth embodiment, a balloon similar to the stent 192 of the fourteenth embodiment is provided. The locking effect on 196 can be exhibited. Therefore, by adopting the shape of the strut 248 of the present embodiment, it is possible to achieve both the effect of preventing the stent 246 from falling off the balloon 196 and the more reliable drug release effect.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited by the specific descriptions, and is implemented in a mode in which various changes, corrections, improvements, and the like are added based on the knowledge of those skilled in the art. Any of such embodiments can be included in the scope of the present invention without departing from the spirit of the present invention.

For example, in the above-described embodiment, the stent has a shape in which a plurality of annular portions 198 made of one linear body 200 are arranged in the axial direction and these are connected to each other by the link portion 202. The shape is not limited to this. That is, for example, the stent may have a shape in which one linear body is folded back in the axial direction and spirally extends in the circumferential direction, may be in a mesh shape, and is attached to a balloon to be a lumen. The stent is not limited as long as it is a stent to be delivered.

Further, in the fourteenth, fifteenth, and seventeenth embodiments, the struts 204, 220, and 248 have a substantially rectangular cross section, and in the sixteenth embodiment, the strut 234 has a rhombus. However, the longitudinal cross-sectional shape of the strut is not limited at all. That is, for example, a circular shape is adopted as the vertical cross-sectional shape of the strut, and a projecting piece that is curved corresponding to the cross-sectional shape of the strut or a flat projecting piece that does not correspond to the cross-sectional shape of the strut can be adopted. Alternatively, a triangle or a pentagon or more polygonal shape may be employed as the longitudinal cross-sectional shape of the strut.

In the fourteenth and seventeenth embodiments, the projecting piece-like balloon linking protrusions 210 and 252 protrude from the inner peripheral surface 208 of the struts 204 and 248 and are locked to the outer peripheral surface of the balloon 196. However, the present invention is not limited to such an embodiment. In other words, the protruding piece-like balloon linking protrusion may extend from the distal end side surface or the proximal end side surface of the strut and be locked to the outer peripheral surface of the balloon.

Further, the balloon linkage projection as the inner circumference linkage projection locked to the balloon does not need to be a protruding piece that deforms with the expansion deformation of the balloon 196. For example, FIG. 61 (a), (b) A balloon linkage protrusion having a shape as shown in FIG. That is, a hemispherical balloon linkage protrusion 260 protrudes from the inner peripheral surface 208 of the strut 258 shown in FIG. 61A, and is locked by slightly biting into the outer peripheral surface of the balloon 196. Like the balloon linking protrusion 260, the stent may be expanded and deformed without being deformed as the balloon 196 is expanded and deformed. In this embodiment, the balloon linkage protrusion does not have to be hemispherical, and may be polygonal in the longitudinal section, for example.

Further, as shown in FIG. 61 (b), the longitudinal section of the strut 262 is an inverted triangle, and one apex angle is located on the inner peripheral side, while the base opposite to the apex angle is the outer periphery. It may be located on the side. In the strut 262 having such a shape, since the apex angle located on the inner peripheral side slightly bites into the balloon 196 and exerts a locking action, the portion of the apex angle located on the inner peripheral side in the strut 262 Can be grasped as the balloon linkage protrusion 264. In this aspect, the longitudinal cross section of the strut does not have to be triangular, but may be a polygon more than a triangle and one apex angle may be located on the inner peripheral side. Further, it is not necessary to have a polygonal shape as a whole, and in a longitudinal section, a combination of a plurality of shapes such as a polygonal shape such as a triangle on the inner peripheral side and a semicircular shape on the outer peripheral side may be used. .

Furthermore, in the stents 192 and 246 in the fourteenth and seventeenth embodiments, the balloon linking protrusions 210 and 252 are plastically deformed so as to overlap the struts 204 and 248 as the balloon 196 expands. However, the present invention is not limited to such an embodiment. That is, it is not necessary for the balloon linkage protrusion and the strut to be completely overlapped due to the expansion deformation of the balloon, and as the balloon linkage protrusion is deformed, the protrusion toward the inner peripheral side is suppressed more than before the deformation. And the effect of preventing luminal restenosis can be exhibited. Even if the deformation of the balloon linkage protrusion is plastic deformation, it is not necessary to maintain the completely deformed shape, and it may be deformed to some extent. That is, the above-described effects can be exhibited as long as the shape before deformation is not restored and deformed. However, in the fourteenth embodiment, the balloon linking protrusion 210 does not need to be deformed with the expansion deformation of the balloon 196, and may be maintained in a shape that protrudes toward the inner peripheral side.

In any of the above embodiments, the deformation of the balloon linking protrusion is preferably plastic deformation, but may be elastic deformation, and the balloon linking protrusion may be elastically deformed as the balloon expands. At the same time, by deflating the balloon and removing the catheter, the balloon linkage projection is restored and restored to its original shape, or the balloon linkage projection 224 is a lumen as in the fifteenth embodiment. It may be impossible to return to the original shape by being pressed against the wall 216 or the like.

Further, the balloon linkage protrusion and the medicine receiving recess may be provided over the entire length of the strut or may be provided partially in the length direction of the strut. Further, the shape of the balloon linkage protrusion and the medicine receiving recess in the thickness direction of the strut is not limited to a substantially rectangular shape as in the above-described embodiment, and is not limited to a polygonal shape such as a triangle or a semicircular shape. It is not limited.

In the fifteenth embodiment, the balloon linking projection 224 has a shape that fits into the drug containing recess 222, and the balloon linking projection 224 fits into the drug receiving recess 222 to accommodate the drug. Although the volume of the recess 222 is set to be substantially zero, the present invention is not limited to such a mode, and the volume of the drug containing recess is reduced by fitting the balloon linkage protrusion into the drug containing recess. If so, the drug can be released into the lumen wall.

Further, in the fourteenth and seventeenth embodiments, the balloon linking protrusions 210 and 252 extend from the inner peripheral surface 208 of the struts 204 and 248 in the direction opposite to the traveling direction of the catheter 194, that is, from the distal end to the proximal end. However, by projecting the balloon linking projection from the proximal end toward the distal end, it is possible to cope with the displacement external force accompanying the movement of the catheter in the lumen in the extraction direction. In addition, the balloon linkage protrusions extending from the distal end side to the proximal end side and the balloon linkage protrusions extending from the proximal end side to the distal end side are alternately provided, for example, in the length direction of the strut, so that the axis of the stent on the balloon can be obtained. The displacement of the direction is suppressed, and the stent can be more effectively prevented from falling off the balloon.

Furthermore, in the fourteenth and seventeenth embodiments, when the balloon 196 is expanded and deformed, the balloon linkage protrusions 210 and 252 are respectively formed on the inner peripheral surface 208 of the struts 204 and 248 and the balloon linkage protrusions 210 and 252, respectively. The inner surface 212 has been deformed so as to be overlapped. However, for example, an accommodation recess corresponding to the balloon linking protrusion is provided on the inner peripheral surface of the strut, and the balloon linking protrusion is deformed as the balloon is expanded and deformed. And may be housed in the housing recess. As a result, it is possible to further suppress the protrusion of the balloon-linked protrusion from the strut surface when the stent is placed in the lumen, and to generate thrombus due to stagnation or turbulence of blood, etc. Restenosis of a lumen such as a blood vessel due to adhering to the blood vessel can be further suppressed.

In the sixteenth and seventeenth embodiments, both the effect of preventing the stent from falling off the balloon and the more reliable drug release effect have been achieved. For example, the balloon linkage collision in the fourteenth embodiment It is also possible to achieve both of the above effects by providing the portion 210 and the balloon linkage protrusion 224 in the fifteenth embodiment at the same time.

Although the stents 192, 218, 232, and 246 described in the above embodiment and the struts 258 and 262 described in FIG. 61 are formed by electroforming, etching is performed instead of electroforming or in combination with electroforming. May be adopted.

Further, the deformation of the balloon linking projection accompanying the expansion deformation of the balloon is pressed to the outer peripheral side by the outer peripheral surface of the balloon 196 or pressed to the inner peripheral side by the lumen wall 216 as in the above-described embodiment. It is not limited. For example, as in the embodiment shown in FIG. 58, if the balloon linking protrusion protrudes from the side surface or the outer peripheral surface of the strut, the strut is not affected directly by the balloon diameter expansion force. The base end portion may be deformed so that the inclination angle becomes smaller during the diameter expansion deformation, and can be overlapped with the side surface or the outer peripheral surface of the strut. In addition, as in the embodiment shown in FIG. 59, in a strut that forms a recess that opens laterally with a cross-sectional shape connected in a link shape, the diameter expansion force of the balloon and the reaction against the lumen wall Even if the force is not directly applied to each link portion, the deformation can be caused in the direction in which both the links overlap so that the connection angle is reduced and the volume of the recess is reduced during the diameter expansion deformation. Furthermore, as shown in FIGS. 62A to 62D, the balloon 196 is expanded by providing balloon linking protrusions extending over a plurality of portions on the strut whose relative positions change when the diameter is expanded. The balloon linkage protrusion may be deformed in accordance with the diameter expansion deformation of the stent accompanying the deformation.

Specifically, in FIGS. 62A and 62B, the main part of the strut 266 attached to the outer peripheral surface of the balloon 196 is shown. The linear body 200 that constitutes the strut 266 of this aspect, like the above-described embodiment, extends in the circumferential direction while being folded back in the axial direction (vertical direction in FIG. 62A) to form an annular portion 198. In the mounted state on the balloon 196 shown in FIG. 62 (a), each annular portion 198 is reduced in diameter. Therefore, the linear body 200 is formed with adjacent portions 268 that are close to each other in the circumferential direction by being reduced in diameter. In the proximity portion 268, the outer peripheral surface 206 of the strut 266 is provided with a drug containing recess 270 that opens to the outer peripheral side, and the drug is stored in the drug containing recess 270.

On the other hand, in the strut 266 of this embodiment, the balloon linking projection 272 is formed with a substantially inverted U-shaped (gate gate shape or tunnel arch shape) ridge so as to cover the outer peripheral side of the adjacent portions 268, 268 adjacent to each other in the circumferential direction. Has been. In other words, the balloon linkage protrusion 272 includes a curved portion 274 that is curved in a shape that is convex toward the outer peripheral side, and linear portions 276 and 276 that extend linearly from both circumferential ends of the curved portion 274, respectively. . The ends of the linear portions 276 and 276 opposite to the curved portion 274 are fixed to the side surfaces of the struts 266 at the adjacent portions 268 and 268. Discharge protrusions 278 and 278 having a shape corresponding to the drug containing recesses 270 and 270 are formed on the inner surface of the balloon linkage protrusion 272.

The struts 266 in this embodiment are deformed so that the adjacent portions 268 and 268 are separated from each other in accordance with the diameter expansion deformation of the stent accompanying the expansion deformation of the balloon 196. Therefore, the struts 266 are illustrated in FIGS. 62 (c) and 62 (d). As shown, the balloon linking projection 272 covering both the proximity portions 268 and 268 is deformed so that the curved portion 274 extends linearly and approaches the strut 266. At the same time, centering on the portion where the linear portions 276, 276 of the balloon linkage protrusion 272 are fixed to the strut 266, the protrusion angle of both leg portions is reduced so as to overlap with the outer peripheral side surface 206 of the strut 266 so that it falls down. Can be transformed. As a result, the discharge protrusions 278 and 278 provided on the inner surface of the balloon linkage protrusion 272 enter the drug storage recesses 270 and 270 formed on the outer peripheral surface 206 of the strut 266 to push out the drug. Yes.

In such an embodiment, the discharge protrusions 278 and 278 of the balloon linkage protrusion 272 are not pressed against the balloon 196 from the inner peripheral side and are not pressed against the lumen wall 216 from the outer peripheral side. 270 can be fitted. However, when the balloon linkage protrusion 272 is pressed from the outer peripheral side by the lumen wall 216, the discharge protrusions 278 and 278 can enter the medicine receiving recesses 270 and 270 more reliably.

In addition, the formation location of the balloon linking protrusions 272 and the number on the periphery in this aspect can be appropriately changed in consideration of the ease of expansion of the stent, the bending rigidity after expansion, and the like. In addition, when the stent is deformed from the reduced diameter state to the expanded diameter state, when the stent extends not only in the radial direction but also in the axial direction, the balloon linkage protrusion 272 extends in the axial direction and approaches in the axial direction of the strut. You may provide so that parts may be covered.

In addition, the specific embodiments of the struts and balloon linking protrusions employed in the present invention are merely illustrative and are not limited in any way. For example, the balloon linkage protrusions 210 and 224 as shown in FIG. 57 and FIG. 58 may have a shape protruding in a curved shape that protrudes inward or outward instead of a shape protruding linearly. Thus, it is possible to improve the locking effect on the balloon surface and to distribute the contact force to the inner surface of the body lumen. Further, with respect to the structure of the entire hollow strut and balloon linking projection that can be interpreted as a link structure as shown in FIG. 59, for example, each contact can be curved. For example, each contact and each link part are curved. It is possible to make the cross-sectional structure of a horizontally long and generally hollow ellipse shape as a whole, thereby improving the chemical solution storage volume or eliminating the acute angle part on the outer periphery and making it a smooth outer peripheral surface shape You can also.

Furthermore, stents having a structure according to the embodiment shown in FIGS. 56 to 62 include stents having different diameters of the main cylindrical portion and the branched cylindrical portion in addition to the Y-shaped branched shape, tapered shape, and thick end shape. A stent in which at least one of the trunk cylinder part and the branch cylinder part has a tapered cylindrical shape, a stent partially tapered in the length direction, and a thick part at an end part or a central part in the length direction. The present invention is applicable to various types of deformed stents such as a provided stent, a stent body excluding a covered stent cover, and a stent bent or bent at an intermediate portion in the longitudinal direction. The stent bent or bent at the intermediate portion in the longitudinal direction is effective for a highly curved or bent portion of a patient having advanced arteriosclerosis.

Furthermore, a stent having a structure according to the present invention may be formed by thermal spraying or vacuum deposition known as a molding technique such as film formation as in electroforming. For example, a stent is formed by integrating a large number of sprayed particles of a material that has been melted or brought close to it into a predetermined shape by heating, or a large number of particles of a material that has been vaporized or sublimated by being heated to a predetermined shape. It is also possible to form a stent by integrating them with each other.

Further, the stent having the structure according to the above-described aspect of the present invention is also applied to a flow diverter for treating a cerebral aneurysm. The flow diverter is, for example, a low-porosity blood flow bypass device improved for endovascular treatment of cerebral aneurysms. Furthermore, the stent structured according to the above aspect of the present invention is also applicable in the case of a tip portion in a stent retriever system. The stent retriever system is, for example, a reticular cylindrical thrombectomy device for efficiently squeezing and removing a thrombus with a net.

10, 50, 60, 62, 68, 124, 140, 144, 154, 160, 168, 192, 218, 232, 246: stent, 12, 52: annular portion (skeleton), 14, 54: link portion (skeleton) ), 16, 22, 28, 38: Strut (skeleton), 18, 24, 30: Core layer, 20, 26: Core decomposition control layer, 40: Contrast layer, 56: Self-expanding region, 58: Hyperdeformation region, 126, 146, 156, 170: first skeleton structure, 128, 148, 158, 172: second skeleton structure, 132, 150, 174: first gap, 138, 152, 176: second gap, 194: catheter, 196: balloon, 204, 220, 234, 248, 258, 262, 266: strut, 206: outer peripheral surface, 208: inner peripheral surface, 210, 244, 260, 64, 272: Balloon linkage projection (inner circumference linkage projection), 222, 236, 250, 270: Drug receiving recess, 224: Balloon linkage projection (outer circumference linkage projection), 242: Second circumference wall ( Balloon linkage projection, outer circumference linkage projection), 252: Balloon linkage projection (extrusion portion)

Claims (29)

1. A stent comprising a cylindrical skeleton that can be expanded and contracted in the radial direction,
   The skeleton has a core layer formed of a biodegradable material;
   A stent characterized in that a core degradation control layer made of a biodegradable material is laminated on a surface of the core layer in the skeleton.
2. The stent according to claim 1, wherein the core decomposition control layer is laminated on both inner and outer peripheral surfaces of the core layer.
3. The core layer is formed of one of a biodegradable metal and a biodegradable resin, and the core decomposition control layer is formed of either the biodegradable metal or the biodegradable resin. The stent according to 1 or 2.
4. The stent according to any one of claims 1 to 3, wherein the core layer has a multilayer structure.
5. The stent according to any one of claims 1 to 4, wherein the skeleton has a contrast layer formed of a radiopaque material.
6. The stent according to any one of claims 1 to 5, wherein the core layer and the core decomposition control layer are formed by at least one of spraying, vapor deposition, etching, and electroforming.
7. A stent comprising a cylindrical skeleton that can be expanded and contracted in the radial direction,
   The skeleton includes a self-expanding region that deforms into a predetermined shape by superelasticity, and a portion of the skeleton that is off the self-expanding region in the axial direction can be deformed larger than the self-expanding region. A stent characterized by being a deformation region.
8. The stent according to claim 7, wherein at least one end in the axial direction of the skeleton is the overdeformed region.
9. The stent according to claim 7 or 8, wherein the over-deformed region is capable of expanding and deforming to a larger diameter than the self-expanding region.
10. The stent according to any one of claims 7 to 9, wherein the over-deformed region is expanded by a balloon so as to be deformable more than the self-expanding region.
11. The stent according to claim 10, wherein a gap in the peripheral wall portion of the over-deformed region is expanded by the balloon so as to be deformed larger than the gap in the self-expanding region.
12. The stent according to any one of claims 7 to 11, wherein the self-expanding region and the overdeformed region are formed by at least one of spraying, vapor deposition, etching, and electroforming.
13. The first skeleton structure provided with the first gap and the second skeleton structure provided with the second gap are integrated with each other in an inseparable manner, and in the second skeleton structure, The stent, wherein the second gap is reduced by the first skeleton structure.
14. While the first skeleton structure is mesh-shaped, the second skeleton structure is coiled extending in the circumferential direction while being folded back in the length direction,
    The stent according to claim 13, wherein the first skeletal structure is located and integrated on an inner peripheral side of the second skeleton structure.
15. While the first skeleton structure is mesh-shaped, the second skeleton structure is coiled extending in the circumferential direction while being folded back in the length direction,
    The stent according to claim 13, wherein the first skeleton structure is located and integrated with an intermediate portion in the thickness direction of the second skeleton structure.
16. Both the first skeleton structure and the second skeleton structure are mesh-shaped, and the first skeleton structure and the second skeleton structure are overlapped in the thickness direction of the peripheral wall. The stent according to claim 13.
17. Both the first skeleton structure and the second skeleton structure are formed in a coil shape extending in the circumferential direction while being folded back in the axial direction, and the first skeleton structure and the second skeleton structure are formed on the peripheral wall. The stent according to claim 13, wherein the stent is overlapped in the thickness direction.
18. The first gap in the first skeleton structure is reduced in the second skeleton structure, and the second gap in the second skeleton structure is reduced in the first skeleton structure. The stent according to claim 16 or 17.
19. The first gap in the first skeleton structure is made smaller than the second gap in the second skeleton structure, and the second skeleton structure is disposed on the outer peripheral side of the first skeleton structure. The stent according to any one of claims 16 to 18, wherein the stent is superposed.
20. The stent according to any one of claims 13 to 19, wherein at least one of the first skeleton structure and the second skeleton structure is formed to have a structure integrated with each other by electroforming or etching.
21. In a stent that is attached to a balloon and delivered to the lumen,
    A stent characterized in that a balloon linking protrusion projecting from the surface of a strut constituting the peripheral wall and linking to the balloon is provided.
22. The stent according to claim 21, wherein the balloon linkage projection is formed on an inner circumferential surface of the strut and is constituted by an inner circumference linkage projection that is locked by a linkage action with respect to the balloon.
23. The balloon linking protrusion is formed as a protruding piece projecting from the surface of the strut, and the balloon linking protrusion is deformed on the surface of the strut as the balloon expands due to the linking action on the balloon. 23. A stent according to claim 21 or 22 adapted to be superposed.
24. The strut is provided with a medicine receiving recess for containing a medicine, and the balloon connecting projection is deformed as the balloon expands due to the linkage action with respect to the balloon so that the volume of the medicine receiving recess is increased. The stent according to any one of claims 21 to 23, wherein the drug is released to the outside by reducing the amount of the drug.
25. The drug-containing recess is provided to open on the outer peripheral surface of the strut, and the balloon-linking projection is deformed along with the expansion deformation of the balloon and enters the drug-containing recess. 25. The stent according to claim 24, wherein the stent is constituted by an outer peripheral linking protrusion that discharges the water.
26. The drug containing recess is provided through the strut in the thickness direction, and the balloon linking projection is deformed along with the expansion deformation of the balloon, and the drug containing recess is formed from the inner peripheral side of the strut. 25. The stent according to claim 24, wherein the stent is constituted by an extruding portion that enters into a place.
27. 27. The stent according to any one of claims 24 to 26, wherein the balloon linkage protrusion has a corresponding shape that fits into the medicine receiving recess.
28. The balloon linking projection protrudes from the inner or outer surface of the strut in an inclined direction in a direction opposite to the traveling direction in the lumen of the catheter to which the balloon is attached. 28. The stent according to any one of 27.
29. The stent according to any one of claims 21 to 28, wherein the balloon link protrusion is integrally formed on the surface of the strut by at least one of electroforming and etching.

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