JP2017169818A - Stent and stent delivery system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stent capable of compatibly achieving high rigidity and high plasticity, and a stent delivery system.SOLUTION: A stent 2 includes: a wire strand 21 whose whole shape is cylindrical, disposed along an axial center O or mutually coaxially disposed with the axial center O, and constitute a plurality of annular rings; and connecting parts 22 for connecting mutually adjacent wire strands 21 along the axial center O each other. Further, the connecting part 22 includes a plurality of grooves 221 having a linear shape and formed along the circumferential direction thereof.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a stent and a stent delivery system.

  A medical device called a stent is used to improve a lesion site such as a stenosis or an obstruction occurring in a living body lumen such as a blood vessel, a bile duct, a trachea, an esophagus, or a urethra (see, for example, Patent Document 1). . This stent is a hollow tubular medical device in which a lesion site is expanded in order to maintain the patency state of the living body lumen, and is placed in the living body lumen in the expanded diameter state. Stents are used, for example, in the coronary arteries of the heart to prevent restenosis after percutaneous coronary angioplasty (PTCA). By placing a stent, the incidence of acute vascular occlusion and restenosis can be reduced.

  The stent described in Patent Document 1 includes a cylindrical ring composed of a large number of rings made of a wire formed in a ring shape, and a connecting portion made of a wavy wire that connects adjacent wires of the cylindrical ring (a wavy link). ). The connecting portion can maintain the overall cylindrical shape of each cylindrical ring and can impart flexibility to the entire stent.

  Such a stent has different characteristics required for a connecting portion after being placed in a living body lumen and being placed in the indwelling state, that is, during placement. After the stent is placed in the indwelling state, the connecting portion is preferably highly flexible. Thereby, the followability to the blood vessel of the whole stent increases. On the other hand, at the time of detention, it is preferable that the connecting portion has high rigidity. Thereby, when expanding a stent, it can be expanded uniformly.

  However, in the conventional stent, it has been difficult to realize these functions required for the stent before and after placement of the stent. For example, in the stent of Patent Document 1, flexibility can be increased by making the connecting portion corrugated, but there is a risk that uniformity during stent expansion may be insufficient due to a decrease in rigidity. In addition, when the wavy shape of the connecting portion is omitted and the shape is a linear rod shape, the rigidity of the entire stent can be increased, but the followability to the living body lumen becomes insufficient after the indwelling state. Thus, it is difficult for a stent to achieve both flexibility and rigidity, which are contradictory properties.

Japanese Patent No. 3725480

  An object of the present invention is to provide a stent and a stent delivery system capable of achieving both high rigidity and high flexibility.

Such an object is achieved by the present inventions (1) to (10) below.
(1) The overall shape is a cylindrical stent,
A plurality of annular portions arranged along the central axis of the stent and concentrically with the central axis of the stent;
Including at least one connecting part that connects the annular parts adjacent to each other along the central axis among the plurality of annular parts,
The connecting portion is linear and has a plurality of grooves formed along the circumferential direction thereof.

  (2) The stent according to (1), wherein the plurality of grooves are arranged side by side along the axial direction of the connecting portion.

  (3) The stent according to (1) or (2), wherein a depth direction of the plurality of grooves coincides with a circumferential direction of the stent.

  (4) The plurality of grooves are provided on the opposite side of the first groove group aligned along the axial direction of the connecting portion and the first groove group via the axis of the connecting portion. The stent according to any one of (1) to (3), further including a second groove group aligned along the axial direction of the connecting portion.

  (5) The locations of the plurality of grooves that the first groove group and the second groove group respectively have are the axis of the coupling portion in the first groove group and the second groove group. The stent according to the above (4), which is displaced from each other in the direction.

  (6) The density of the grooves at both ends of the connecting portion is higher than the density of the grooves in the middle of the connecting portion in the axial direction, according to any one of (1) to (5). Stent.

  (7) The stent according to any one of (1) to (6), wherein a width of the groove at both ends of the connection portion is larger than a width of the groove in the middle of the connection portion in the axial direction.

  (8) The stent according to any one of (1) to (7), wherein a depth of the groove at both ends of the connecting portion is deeper than a depth of the groove in the middle of the connecting portion in the axial direction.

  (9) The stent according to any one of (1) to (8), wherein the groove is filled with a biodegradable material that is decomposed by contact with a body fluid.

(10) The stent according to any one of (1) to (9) above,
A stent delivery system comprising: a delivery device that removably holds the stent and that delivers the stent into a living body lumen.

  According to the present invention, since the connecting portion is linear, it contributes to increasing the rigidity of the entire stent. Furthermore, since a plurality of grooves are provided in the connecting portion, it contributes to increasing the flexibility of the entire stent. Thus, according to the present invention, it is possible to achieve both high rigidity and high flexibility, which are mutually contradictory characteristics in the stent.

FIG. 1 is a side view showing a first embodiment of the stent and stent delivery system of the present invention. FIG. 2 is an enlarged side view showing an indwelling state of the stent shown in FIG. FIG. 3 is an enlarged side view of a connecting portion of the stent shown in FIG. FIG. 4 is an enlarged side view showing a state where the connecting portion is bent and deformed before the stent shown in FIG. 1 is placed. FIG. 5 is an enlarged side view showing a state in which the connecting portion is bent and deformed after a predetermined time has elapsed since the stent shown in FIG. 1 is placed. FIG. 6 is an enlarged side view of a connecting portion provided in the second embodiment of the stent and stent delivery system of the present invention. FIG. 7 is an enlarged side view of a connecting portion provided in the third embodiment of the stent and stent delivery system of the present invention. FIG. 8 is an enlarged side view of a connecting portion provided in the fourth embodiment of the stent and stent delivery system of the present invention. FIG. 9 is a side view of a stent provided in a fifth embodiment of the stent and stent delivery system of the present invention. FIG. 10 is an enlarged side view of a connecting portion provided in the sixth embodiment of the stent and stent delivery system of the present invention.

  Hereinafter, a stent and a stent delivery system of the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.

<First Embodiment>
FIG. 1 is a side view showing a first embodiment of the stent and stent delivery system of the present invention. FIG. 2 is an enlarged side view showing an indwelling state of the stent shown in FIG. FIG. 3 is an enlarged side view of a connecting portion of the stent shown in FIG. FIG. 4 is an enlarged side view showing a state where the connecting portion is bent and deformed before the stent shown in FIG. 1 is placed. FIG. 5 is an enlarged side view showing a state in which the connecting portion is bent and deformed after a predetermined time has elapsed since the stent shown in FIG. 1 is placed.

  In the following, for convenience of explanation, the upper side of FIGS. 1 to 5 (the same applies to FIGS. 6 to 10) is “upper” or “upper”, the lower side is “lower” or “lower”, and the left side is “ The “left side” or “front end side” and the right side are referred to as “right side” or “proximal side”.

  A stent delivery system 1 shown in FIG. 1 includes a stent 2 placed in a living body lumen, and a delivery catheter 3 (transport device) that transports the stent 2.

  The stent 2 is a medical instrument for supporting a lesion site such as a stenosis part or an obstruction part generated in a living body lumen such as a blood vessel, a bile duct, a trachea, an esophagus, a urethra from the inside, and maintaining a patent state. In the following description, as an example, the stent 2 is described as supporting the stenosis portion 101 generated in the blood vessel 100.

Prior to describing the stent 2, the delivery catheter 3 will be described.
The delivery catheter 3 includes a tubular catheter body 31, a hub 32 provided at the proximal end portion of the catheter body 31, and a balloon 33 provided near the distal end portion of the catheter body 31. The outer diameter of the balloon 33 is expanded when a working fluid is supplied through a flow path (not shown). The stent 2 is disposed on the outer peripheral portion of the balloon 33 with the outer diameter reduced.

  For example, the delivery catheter 3 is inserted into the living body so as to pass through a guide wire that has been inserted into the blood vessel 100 in advance. When the stenosis 101 is reached, the balloon 33 is expanded. Thereby, the stent 2 is pushed and expanded by the balloon 33, and becomes a diameter-expanded state. In this expanded diameter state, the narrowed portion 101 can be supported from the inside, and the stenotic portion 101 can be maintained in an open state. Then, the delivery catheter 3 is removed from the blood vessel 100, and only the stent 2 is left in the living body.

Next, the stent 2 will be described.
The stent 2 includes an element wire 21 having a spiral shape around an axis (center axis) O and a plurality of connecting portions 22 that connect the adjacent element wires 21 in the axial direction. Yes.

  The stent 2 has a cylindrical shape whose entire outer shape is constant from the distal end to the proximal end. In addition, in the strand 21, the strand 21 is wound a number of times, and one round (one turn) is an annular portion, and the annular portion is concentrically along the axis O. It can be said that a plurality are arranged side by side.

  The strand 21 has a wave shape in which peaks and valleys are alternately arranged. For this reason, it is possible to secure a sufficient area where the strands 21 are in contact with the constricted portion 101. Therefore, the constricted portion 101 can be sufficiently supported.

  The connecting portion 22 connects adjacent strands 21 along the axis O, and maintains the arrangement state of the strands 21. The connecting portion 22 is linear in a natural state where no external force is applied to the stent 2. Moreover, the connection part 22 has connected the part used as a wavy peak and the part used as a trough in the adjacent strand 21. FIG.

  The stent 2 is not limited to the above-described spiral tube body, and for example, has a shape in which a large number of rings are concentrically connected, or a mesh shape in which a large number of strands are folded into a net shape. It may be.

  The stent 2 can take a reduced diameter state (see FIG. 1) and an expanded state (see FIG. 2) in which the inner diameter and the outer diameter are larger than the reduced diameter state.

  In addition, the stent 2 is expanded in diameter by the balloon 33 and is placed in the blood vessel 100 in the expanded diameter state. In the expanded diameter state, the undulations of the strands 21 are deformed, and adjacent apexes are separated from each other than in the reduced diameter state. Thus, the stent 2 is a so-called “balloon expandable stent”.

  The stent 2 may be constituted by a so-called “self-expanding stent” that expands by its own elasticity. In this case, in a double-tube catheter having an outer tube and an inner tube, a stent is disposed between the outer tube and the inner tube to maintain the reduced diameter state, that is, the outer tube is expanded in diameter. And is inserted into the living body in this state. Then, by moving the outer tube relative to the inner tube relative to the proximal side of the catheter, the restriction by the outer tube is released, and the stent can be configured to be in an expanded state.

  Such a stent 2 can be obtained, for example, by partially removing a cylindrical member by laser irradiation. In addition, the constituent material of the stent 2 is not particularly limited, but for example, a pseudo alloy such as a cobalt-based alloy such as stainless steel or a cobalt-chromium alloy, a Ni-Ti-based alloy, a Cu-Zn-based alloy, or a Ni-Al-based alloy. Relatively high rigidity such as various metals such as elastic metal, tungsten, tungsten alloy, titanium, titanium alloy, tantalum, polyamide, polyimide, ultra high molecular weight or high molecular weight polyolefin (polyethylene, polypropylene, etc.), fluorine resin, etc. Molecular materials or the like can be used.

  Now, the connecting portion 22 is provided with a plurality of grooves 221. Since each groove 221 of each connecting portion 22 has the same shape except that the formation location is different, hereinafter, one groove 221 of the connecting portion 22 surrounded by a broken line shown in FIG. 2 will be representatively described.

  As shown in FIG. 3, the groove 221 is provided along the circumferential direction of the connecting portion 22. The groove 221 has a rounded bottom portion 222. Further, the bottom portion 222 is located in the vicinity of the axis O ′ in the illustrated configuration. Further, the width of the groove 221 is substantially constant up to the bottom portion 222.

  Such grooves 221 can be divided into a first groove group 221A and a second groove group 221B.

  In the first groove group 221A, the groove 221 is provided on the upper side in FIG. In the first groove group 221A, the grooves 221 are provided at equal intervals (equal pitch).

  The second groove group 221B is provided in the connecting portion 22 on the opposite side (lower side in FIG. 3) of the first groove group 221A via the axis O ′ of the connecting portion 22. In the second groove group 221B, the grooves 221 are provided at equal intervals (equal pitch). The interval between the grooves 221 in the second groove group 221B is the same as the interval between the grooves 221 in the first groove group 221A.

  Further, the groove 221 of the first groove group 221 </ b> A and the groove 221 of the second groove group 221 </ b> B are displaced from each other in the direction along the axis O ′ of the connecting portion 22. For this reason, when viewed in the entire connecting portion 22, the grooves 221 of the first groove group 221A and the grooves 221 of the second groove group 221B are alternately provided in the direction of the axis O ′.

  When the stent 2 is bent and deformed, the connecting portion 22 is bent and deformed accordingly. At the time of this deformation, the connecting portion 22 can prevent the cylindrical shape of the strands 21 from being largely collapsed, and the arrangement state of the strands 21 can be maintained.

  Moreover, the connection part 22 has comprised the linear rod shape in the natural state. Thereby, the stent can be expanded uniformly during expansion.

  Further, since the connecting portion 22 is provided with a plurality of grooves 221, the connecting portion 22 is easily deformed starting from a portion where the groove 221 is provided during the deformation. As shown in FIG. 5, in the case of bending upward in FIG. 5, the two side surfaces 223 of the grooves 221 of the first groove group 221A are deformed so as to be separated from each other, that is, the grooves 221 are opened. be able to. Thereby, a softness | flexibility can be provided to the connection part 22, and sufficient softness | flexibility can be ensured as the stent 2 whole. Therefore, in the indwelling state, the entire stent 2 can be easily deformed following the deformation of the blood vessel 100. As a result, it is possible to prevent an excessive burden on the blood vessel 100.

  Thus, according to the stent 2, it is possible to achieve both high rigidity and high flexibility, which are mutually contradictory characteristics. As a result, the stent 2 can be uniformly expanded in the blood vessel 100 and can prevent the blood vessel 100 from being burdened in the indwelling state.

  Moreover, each groove | channel 221 makes the circumferential direction of the stent 2 the depth direction. That is, each groove 221 is formed with a groove 221 in the circumferential direction of the stent 2.

  As shown in FIG. 3, the width W of the groove 221 (the distance between the side surfaces 223) is not particularly limited, but the thickness L of the connecting portion 22 (the direction of the axis O ′ of the connecting portion 22) 1% to 35%, and more preferably 10% to 30% of the maximum length of the perpendicular to the vertical axis. Thereby, the flexibility of the connecting portion 22 can be increased and sufficient rigidity can be ensured, and the effects of the present invention can be further exhibited.

  Further, the depth (maximum depth) D of the groove 221 is preferably 5% or more and 70% or less of the thickness L of the connecting portion 22, and more preferably 30% or more and 60% or less. Thereby, the flexibility of the connecting portion 22 can be increased and sufficient rigidity can be ensured, and the effects of the present invention can be further exhibited.

  The pitch P (center distance) between the grooves 221 is not particularly limited, but is preferably smaller than the thickness L of the connecting portion 22. Further, the pitch P between the grooves 221 is preferably 50% or more and 300% or less of the thickness L of the connecting portion 22, and more preferably 100% or more and 200% or less. Thereby, the flexibility of the connecting portion 22 can be increased and sufficient rigidity can be ensured, and the effects of the present invention can be further exhibited.

  Here, before the indwelling state is set, the groove 221 is filled with a biodegradable material 5 that is decomposed and eluted by contact with a body fluid such as blood. Before the indwelling state, the separation distance between both side surfaces 223 of the groove 221 is maintained by the biodegradable material 5. Thereby, the rigidity of the whole connection part 22 can be improved. Therefore, as shown in FIG. 4, when the connecting portion 22 is curved and deformed upward in FIG. 4, the biodegradable material 5 on the lower side in FIG. 4 maintains the separation distance between both side surfaces 223 of the groove 221. It can suppress approaching.

  On the other hand, when a predetermined time elapses after the indwelling state, the biodegradable material 5 comes into contact with blood and decomposes and disappears. As a result, as shown in FIG. 5, when the connecting portion 22 is curved and deformed upward in FIG. 5, the distance between both side surfaces 223 of the groove 221 is maintained by the biodegradable material 5 on the lower side in FIG. The two side surfaces 223 of the grooves 221 of the second groove group 221B are likely to be close to each other. That is, the groove 221 can be easily opened and closed. Therefore, the flexibility of the connecting portion 22 can be increased. As a result, in the indwelling state of the stent 2, the stent 2 easily follows the deformation of the blood vessel 100, and the burden on the blood vessel 100 can be reduced.

  As described above, since the biodegradable material 5 is filled in the groove 221, when the stent 2 is expanded, the rigidity of the stent 2 can be increased and the stent 2 can be expanded uniformly. Then, after the stent 2 becomes indwelled in the blood vessel 100 and a predetermined time has elapsed, the flexibility of the stent 2 can be increased and the burden on the blood vessel 100 can be reduced.

  Such a biodegradable material is not particularly limited, and for example, a biodegradable metal material or a biodegradable polymer material can be used.

  As the biodegradable metal material, for example, pure magnesium or a magnesium alloy, calcium, zinc, lithium, or the like can be used. Preferably, pure magnesium or a magnesium alloy can be used.

  The magnesium alloy contains magnesium as a main component and contains at least one element selected from a biocompatible element group consisting of Zr, Y, Ti, Ta, Nd, Nb, Zn, Ca, Al, Li, and Mn. Those that do are preferred. Thereby, even if a biodegradable material is decomposed | disassembled and eluted, it can prevent having a bad influence on a human body.

  Specific examples of the magnesium alloy include, for example, magnesium 50 to 98%, lithium (Li) 0 to 40%, iron 0 to 5%, other metals or rare earth elements (cerium, lanthanum, neodymium, praseodymium, etc.) Is 0 to 5%. Further, for example, magnesium is 79 to 97%, aluminum is 2 to 5%, lithium (Li) is 0 to 12%, and rare earth elements (cerium, lanthanum, neodymium, praseodymium, etc.) are 1 to 4%. be able to. Moreover, for example, magnesium is 85 to 91%, aluminum is 2%, lithium (Li) is 6 to 12%, and rare earth elements (cerium, lanthanum, neodymium, praseodymium, etc.) are 1%. Also, for example, magnesium is 86 to 97%, aluminum is 2 to 4%, lithium (Li) is 0 to 8%, and rare earth elements (cerium, lanthanum, neodymium, praseodymium, etc.) are 1 to 2%. be able to. Also, for example, aluminum is 8.5 to 9.5%, manganese (Mn) is 0.15 to 0.4%, zinc is 0.45 to 0.9%, and the remainder is magnesium. it can. Moreover, for example, aluminum is 4.5 to 5.3%, manganese (Mn) is 0.28 to 0.5%, and the remainder is magnesium. For example, magnesium is 55 to 65%, lithium (Li) is 30 to 40%, and other metals and / or rare earth elements (cerium, lanthanum, neodymium, praseodymium, etc.) are 0 to 5%. Can do.

  On the other hand, examples of the biodegradable polymer material include polylactic acid, polyglycolic acid, lactic acid-glycolic acid copolymer, polycaprolactone, polyhydroxybutyric acid, polyhydroxybutyrate valeric acid, polymalic acid, and poly-α-amino acid. At least one polymer selected from the group consisting of polyorthoesters, cellulose, collagen, laminin, heparan sulfate, fibronectin, vitronectin, chondroitin sulfate, hyaluronic acid, cinnamic acid, and cinnamic acid derivatives. The copolymer is preferably a copolymer obtained by arbitrarily copolymerizing a monomer, and a mixture of a polymer and a copolymer. Among these, from the viewpoint of biocompatibility, polylactic acid (PLA), polyglycolic acid (PGA), or lactic acid-glycolic acid copolymer (PLGA) is particularly preferable.

  Polylactic acid (PLA), polyglycolic acid (PGA), or lactic acid-glycolic acid copolymer (PLGA) may be synthesized by purchasing commercially available products. In the case of synthesis, for example, L-lactic acid It can be obtained by dehydrating polycondensation using D-lactic acid and glycolic acid having a required structure as a raw material. Preferably, it can be obtained by ring-opening polymerization by selecting one having a required structure from lactide, which is a cyclic dimer of lactic acid, and glycolide, which is a cyclic dimer of glycolic acid. Lactide includes L-lactide, which is a cyclic dimer of L-lactic acid, D-lactide, which is a cyclic dimer of D-lactic acid, meso-lactide obtained by cyclic dimerization of D-lactic acid and L-lactic acid, and D- There is DL-lactide, which is a racemic mixture of lactide and L-lactide. Any lactide can be used in the present invention.

  The biodegradable polymer material may contain a plasticizer. If the plasticizer is contained, the ductility of the biodegradable polymer material is improved, and cracks that may occur when the connecting portion 22 is deformed can be prevented.

  The plasticizer is not particularly limited as long as it does not adversely affect the human body, but polyethylene glycol, polyoxyethylene polyoxypropylene glycol, polyoxyethylene sorbitan monooleate, polyethylene glyceryl triricinoleate, sorbitan sesquioleate , Triethyl citrate, acetyl tributyl citrate, acetyl trihexyl citrate, butyryl trihexyl citrate, medium chain fatty acid triglycerides, monoglycerides, and acetylated monoglycerides, or a mixture thereof It is preferable.

  The content of the plasticizer is preferably 0.01 to 80% by mass, more preferably 0.1 to 60% by mass, and preferably 1 to 40% with respect to the biodegradable polymer material. More preferably, it is mass%.

Second Embodiment
FIG. 6 is an enlarged side view of a connecting portion provided in the second embodiment of the stent and stent delivery system of the present invention.

Hereinafter, the second embodiment of the stent and stent delivery system of the present invention will be described with reference to this figure, but the description will focus on differences from the above-described embodiment, and the description of the same matters will be omitted.
This embodiment is substantially the same as the first embodiment described above except that the configuration of the connecting portion is different.

  As shown in FIG. 6, in the connecting portion 22 of the stent 2 </ b> A, the depth D <b> 1 of the groove 221 at the distal end portion 224 and the proximal end portion 225 is an intermediate portion in the axial direction (axial direction) of the connecting portion 22. It is deeper than the depth D2 of the groove 221 in the intermediate part 226. Thereby, in the connection part 22, the softness | flexibility of the front-end | tip part 224 and the base end part 225 can be made higher than the intermediate part 226. FIG. Therefore, even when the stent 2 is placed in the blood vessel 100 and the stent 2 is unintentionally deformed, even if stress is concentrated on the distal end portion 224 and the proximal end portion 225 due to the displacement of the adjacent strands 21. In the connection portion 22 of the stent 2A, the flexibility of the distal end portion 224 and the proximal end portion 225 is higher than that of the intermediate portion 226, so that stress concentration at the distal end portion 224 and the proximal end portion 225 can be reduced. That is, the front end portion 224 and the base end portion 225 can function as a buffer portion having a buffering action. As a result, it is possible to prevent the distal end portion 224 and the proximal end portion 225 from being bent due to stress concentration.

  The depth D1 of the groove 221 at the distal end portion 224 and the base end portion 225 is preferably 100% or more and 300% or less of the depth D2 of the groove 221 at the intermediate portion 226, preferably 1500% or more and 200% or less. It is more preferable that Thereby, the said effect can be exhibited reliably.

<Third Embodiment>
FIG. 7 is an enlarged side view of a connecting portion provided in the third embodiment of the stent and stent delivery system of the present invention.

Hereinafter, the third embodiment of the stent and stent delivery system of the present invention will be described with reference to this figure, but the description will focus on the differences from the above-described embodiment, and the description of the same matters will be omitted.
This embodiment is substantially the same as the first embodiment described above except that the configuration of the connecting portion is different.

  As shown in FIG. 7, in the connecting portion 22 of the stent 2B, the width W1 of the groove 221 at the distal end portion 224 and the proximal end portion 225 is an intermediate portion in the middle of the connecting portion 22 in the axial direction (axial direction). It is larger than the width W2 of the groove 221 in the portion 226. Thereby, in the connection part 22, the softness | flexibility of the front-end | tip part 224 and the base end part 225 can be made higher than the intermediate part 226. FIG. Therefore, when the stent 2 is deformed, the stress concentration generated in the distal end portion 224 and the proximal end portion 225 can be relaxed due to the displacement of the adjacent strands 21. As a result, it is possible to prevent the distal end portion 224 and the proximal end portion 225 from being bent due to stress concentration.

  The width W1 of the groove 221 at the distal end portion 224 and the base end portion 225 is preferably 100% or more and 300% or less of the width W2 of the groove 221 at the intermediate portion 226, and is 125% or more and 200% or less. Is more preferable. Thereby, the said effect can be exhibited reliably.

<Fourth embodiment>
FIG. 8 is an enlarged side view of a connecting portion provided in the fourth embodiment of the stent and stent delivery system of the present invention.

Hereinafter, the fourth embodiment of the stent and stent delivery system of the present invention will be described with reference to this figure, but the description will focus on differences from the above-described embodiment, and the description of the same matters will be omitted.
This embodiment is substantially the same as the first embodiment described above except that the configuration of the connecting portion is different.

  As shown in FIG. 8, in the connection portion 22 of the stent 2 </ b> C, the arrangement density of the grooves 221 at the distal end portion 224 and the proximal end portion 225 is a portion in the middle of the axial direction (axial direction) of the connection portion 22. The arrangement density of the grooves 221 in the intermediate portion 226 is larger. Thereby, in the connection part 22, the softness | flexibility of the front-end | tip part 224 and the base end part 225 can be made higher than the intermediate part 226. FIG. Therefore, when the stent 2 is deformed, the stress concentration generated in the distal end portion 224 and the proximal end portion 225 can be relaxed due to the displacement of the adjacent strands 21. As a result, it is possible to prevent the distal end portion 224 and the proximal end portion 225 from being bent due to stress concentration.

  The arrangement density of the grooves 221 at the distal end 224 and the base end 225 is preferably 100% or more and 300% or less of the arrangement density of the grooves 221 at the intermediate part 226, and is 125% or more and 200% or less. It is more preferable that Thereby, the said effect can be exhibited reliably.

<Fifth Embodiment>
FIG. 9 is a side view of a stent provided in a fifth embodiment of the stent and stent delivery system of the present invention.

  Hereinafter, a fifth embodiment of the stent and stent delivery system of the present invention will be described with reference to this figure, but the description will focus on the differences from the above-described embodiment, and the description of the same matters will be omitted.

  The present embodiment is substantially the same as the first embodiment described above except that the arrangement density of the grooves of the connecting portion differs depending on the site in the axial direction of the stent.

  As shown in FIG. 9, in the stent 2 </ b> D, the arrangement density of the grooves 221 of the connecting portion 22 is different between the site 23 on the distal end side and the site 24 on the proximal end side from the center in the axial direction. The arrangement density of the grooves of the connection portion 22 (hereinafter referred to as “connection portion 22A”) in the portion 23 is larger than the arrangement density of the grooves of the connection portion 22 (hereinafter referred to as “connection portion 22B”) in the portion 24. . For this reason, the connecting portion 22A is more flexible than the connecting portion 22B. Thereby, when it sees with the stent 2D, the site | part 23 has become high flexibility, and the site | part 24 has high rigidity.

  According to such a configuration, the rigidity of the portion 24 is increased, and the strength of the stent 2D in the axial direction is increased. When the axial strength of the stent 2D increases, when another device is inserted after the stent 2D is placed in the blood vessel 100, the other device contacts the proximal end of the stent 2D, and the shape of the stent changes (deformation). ) Or damage (fracture). Moreover, since the site | part 23 has a high softness | flexibility, the blood vessel followability after indwelling the stent 2D is securable.

<Sixth Embodiment>
FIG. 10 is an enlarged side view of a connecting portion provided in the sixth embodiment of the stent and stent delivery system of the present invention.

  Hereinafter, the sixth embodiment of the stent and stent delivery system of the present invention will be described with reference to this figure. However, the difference from the above-described embodiment will be mainly described, and description of similar matters will be omitted.

  The present embodiment is substantially the same as the first embodiment described above, except that the width of the groove of the connecting portion differs depending on the site in the axial direction of the stent.

  As shown in FIG. 10, in the stent 2 </ b> E, the width of the groove 221 in the connection portion 22 is different between the distal end portion 23 and the proximal end portion 24 relative to the axial center.

  The groove 221 of the connecting portion 22 of the portion 23 (hereinafter referred to as “connecting portion 22C”) has the same depth as the groove 221 of the connecting portion 22 of the portion 24 (hereinafter referred to as “connecting portion 22D”). , Wider. For this reason, the connecting portion 22C is more flexible than the connecting portion 22D. Thereby, when it sees with the stent 2E whole, the softness | flexibility of the site | part 23 can be improved and the rigidity of the site | part 24 can be improved. According to such a configuration, both the flexibility and rigidity of the stent 2E can be enhanced, as in the fifth embodiment.

  As described above, the stent and the stent delivery system of the present invention have been described with respect to the illustrated embodiment. However, the present invention is not limited to this, and each part constituting the stent and the stent delivery system exhibits the same function. It can be replaced with any configuration obtained. Moreover, arbitrary components may be added.

  In each of the above-described embodiments, the stent is described as being placed in a stenosis portion in a blood vessel as an example. However, the present invention is not limited to this, and for example, a biological lumen such as a bile duct, trachea, esophagus, urethra, etc. It may be indwelled at the lesion site.

  Further, in each of the above embodiments, the biodegradable material is filled in the groove, but the present invention is not limited to this. For example, the biodegradable material is added to the groove and connected to the connecting portion. You may cover the whole outer periphery.

DESCRIPTION OF SYMBOLS 1 Stent delivery system 2 Stent 2A Stent 2B Stent 2C Stent 2D Stent 2E Stent 21 Strand 22 Connection part 22A Connection part 22B Connection part 22C Connection part 22D Connection part 221 Groove 221A 1st groove group 221B 2nd groove group 222 Bottom 223 Both side surfaces 224 End portion 225 Base end portion 226 Intermediate portion 23 Site 24 Site 3 Delivery catheter 31 Catheter body 32 Hub 33 Balloon 5 Biodegradable material 100 Blood vessel 101 Stenosis D depth D1 depth D2 depth L thickness O Axis O 'Axis P Pitch W Width W1 Width W2 Width

Claims (10)

The overall shape is a cylindrical stent,
A plurality of annular portions arranged along the central axis of the stent and concentrically with the central axis of the stent;
Including at least one connecting part that connects the annular parts adjacent to each other along the central axis among the plurality of annular parts,
The connecting portion is linear and has a plurality of grooves formed along the circumferential direction thereof.   The stent according to claim 1, wherein the plurality of grooves are arranged along the axial direction of the connecting portion.   The stent according to claim 1 or 2, wherein a depth direction of the plurality of grooves coincides with a circumferential direction of the stent.   The plurality of grooves are provided on the opposite side of the first groove group, which is aligned along the axial direction of the connecting portion, and the first groove group via the shaft center of the connecting portion. The stent according to any one of claims 1 to 3, further comprising a second groove group aligned along the axial direction of the portion.   The plurality of grooves provided in the first groove group and the second groove group are arranged in the axial direction of the connecting portion in the first groove group and the second groove group, respectively. The stent according to claim 4, wherein the stent is displaced.   The stent according to any one of claims 1 to 5, wherein a disposition density of the grooves at both ends of the connecting portion is higher than a disposition density of the grooves in the axial direction of the connecting portion.   The stent according to any one of claims 1 to 6, wherein a width of the groove at both ends of the connecting portion is larger than a width of the groove in the middle of the connecting portion in the axial direction.   The stent according to any one of claims 1 to 7, wherein a depth of the groove at both end portions of the connecting portion is deeper than a depth of the groove in an axial direction of the connecting portion.   The stent according to any one of claims 1 to 8, wherein the groove is filled with a biodegradable material that is decomposed by contact with a body fluid. A stent according to any one of claims 1 to 9,
A stent delivery system comprising: a delivery device that removably holds the stent and that delivers the stent into a living body lumen.

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