JP2019122556A - Stent - Google Patents

Abstract

To provide a stent which has high expansion holding power and high flexibility and can be placed at an appropriate position for a living body.SOLUTION: The stent comprises: a plurality of annular parts 20 formed annularly by repeatedly folded wire rods and arranged in an axial direction X of a cylindrical body so as to form the single cylindrical body; and link parts 30 each connecting the annular parts 20 adjacent to each other. Each link part 30 has, in its outer surface 11 positioned on the outer peripheral surface side of the stent, a groove 15 continuous between two side surfaces 12 adjacent to the outer surface 11.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a stent for maintaining the open state of a biological lumen.

  In recent years, for example, in the treatment of myocardial infarction and angina pectoris, a procedure is performed in which a stent is indwelled in a lesion (narrowed part) of a coronary artery to maintain the patency state of the coronary artery. This procedure may also be performed for the treatment of other blood vessels, bile ducts, trachea, esophagus, urethra, and other constrictions that occur in the body lumen.

  Patent Document 1 describes a stent in which a plurality of annular portions formed in an annular shape while being folded back in a wave shape are connected by a link portion. A recess is formed on the outer surface of the link, and a drug for suppressing restenosis is disposed in the recess. Since the annular portions are connected by the link portion, the stent can well hold the expanded state of the indwelling blood vessel.

  In addition, it is preferable that a stent can follow and deform | transform a blood vessel so that it may not put a burden on the indwelling blood vessel. Since a blood vessel is often curved, a stiff stent places a heavy burden on the blood vessel. For this reason, there is known a stent in which a link portion is broken by the expansion force of a balloon when indwelling in a blood vessel (see Patent Document 2). When the link portion is cut and the annular portion is separated, the stent becomes flexible and is likely to follow the blood vessel and deform. This reduces the burden on the blood vessel due to the stent.

US Patent Application Publication No. 2003/0028242 JP, 2011-245001, A

  When the link portion is cut and the annular portion is separated, the burden on the living body of the stent can be reduced, but the force for holding the expanded state of the blood vessel may be reduced.

  The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a stent which has high expansion holding power and high flexibility and can be deployed at an appropriate position with respect to a living body.

  A stent according to the present invention for achieving the above object is annularly formed by a wire rod which is repeatedly folded back, and a plurality of annular portions arranged in the axial direction of the cylinder so as to form one cylinder, A stent having a link portion connecting annular portions, wherein the link portion is a groove portion which is continuous on an outer surface located on the outer peripheral surface side of the stent and between two side surfaces adjacent to the outer surface. Are formed.

  The stent configured as described above has high expansion holding power. Furthermore, since the continuous groove extending between the two side surfaces is formed on the outer surface side, which has a high contribution to the bending rigidity of the stent, the bending rigidity is reduced and the flexibility is improved. In addition, since the stent has a groove on the outer surface side that is not slippery with respect to the contacting living tissue, it can be placed at an appropriate position with respect to the living lumen.

  The groove portion may not be formed in the link portion connected to either of the two annular portions located at both axial ends of the stent. For this reason, the rigidity of the both ends of the axial direction of a stent can be maintained highly, and the curling of both ends can be suppressed.

  The link portion in which the groove portion is formed may be connected to a bent bend portion of the annular portion. Thus, when the stent is expanded, the bend is pressed against the wall of the biological lumen, and the outer surface of the link connected to the bend is pressed against the wall of the biological lumen. The link portion is not slippery with respect to the lumen wall because the groove portion is formed. Thus, the stent can be deployed at an appropriate position relative to the biological lumen.

  The side surface may have a first side connecting two adjacent annular portions, and the groove may cross between the two first side surfaces. This allows the stent to be easily bent at the link, resulting in high flexibility.

  The side surface has a second side surface of each of the two adjacent annular portions opposite to the side to which the link portion is connected, and the groove portion is provided between the two second side surfaces. You may cross Thereby, in the link portion having the groove portion, the angle of the wire forming the stent with respect to the axis of the stent is easily changed. This makes the stent flexible and easy to expand.

  The link portion may be integrally formed with the annular portion. This allows the stent to exert higher expansion retention.

  A drug layer may be provided on the outer surface of the stent, and the drug layer may not be provided at the site where the groove is formed. As a result, since the drug layer does not exist at a site where the groove is formed and which is easily deformed, it is possible to suppress the drug layer from falling off the stent.

It is a top view which shows a balloon catheter. It is a developed view showing a part of stent concerning a 1st embodiment. It is an expanded development view showing a part of stent concerning a 1st embodiment. It is an expansion development view showing the state where the stent concerning a 1st embodiment was expanded. It is a perspective view showing a part of stent concerning a 1st embodiment. It is an expanded development view showing a part of stent concerning a 2nd embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The dimensional ratios in the drawings may be exaggerated and differ from the actual ratios for the convenience of description.

First Embodiment
The stent 10 according to the first embodiment is used to treat a stenosis or an occlusion in a blood vessel, a bile duct, a trachea, an esophagus, a urethra, or another living body lumen. In the present specification, the side to be inserted into the lumen is referred to as the “tip side”, and the hand side to be operated is referred to as the “proximal side”.

  The stent 10 is a so-called balloon expandable stent which is expanded by the expansion force of the balloon 130 as shown in FIG. First, the balloon catheter 100 will be described.

  The balloon catheter 100 comprises an elongated catheter body 120, a balloon 130 provided at the tip of the catheter body 120, and a hub 140 secured to the proximal end of the catheter body 120.

  The catheter body 120 includes an outer tube 150 and an inner tube 160 disposed inside the outer tube 150.

  Inside the outer tube 150, an expansion lumen 151 through which an expansion fluid for expanding the balloon 130 flows is formed. The distal end of the outer tube 150 is fixed to the proximal end of the balloon 130. The proximal end of the outer tube 150 is fixed to the hub 140.

  Inside the inner tube 160, a guide wire lumen 161 into which a guide wire is inserted is formed. The distal end portion of the inner tube 160 penetrates the inside of the balloon 130 and is opened distal to the balloon 130. The proximal end of the inner tube 160 penetrates the side wall of the outer tube 150 on the more proximal side than the balloon 130 and is fixed to the outer tube 150.

  Hub 140 includes a proximal end opening 141 in communication with the expansion lumen 151 of outer tube 150. The proximal end opening 141 functions as a port for inflow and outflow of the expansion fluid.

  The balloon 130 is a member that spreads the narrowed portion, for example, by expanding inside the narrowed portion. The balloon 130 has a cylindrical portion 131 having substantially the same diameter at the central portion in the axial direction so that the predetermined range can be efficiently expanded. The stent 10 according to the present embodiment is placed on the outside of the cylindrical portion 131 of the contracted balloon 130 in a contracted state. The distal end side of the balloon 130 is fixed to the outer wall surface of the inner tube 160. The proximal end side of the balloon 130 is fixed to the outer wall surface of the distal end portion of the outer tube 150. Therefore, the inside of the balloon 130 communicates with the dilation lumen 151 formed in the outer tube 150. For this reason, the inside of the balloon 130 can flow in the dilation fluid from the proximal end opening 141 via the dilation lumen 151. The balloon 130 is expanded by the inflow of the expanding fluid, and is in a folded state by discharging the inflowing expanding fluid. The balloon 130 is shaped so as to be folded in a circumferential direction around the outer peripheral surface of the inner tube 160 in the non-expanded state.

  The balloon 130 is preferably formed of a material having a certain degree of flexibility. As such a material, for example, polyolefin such as polyethylene, polypropylene, polybutene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ionomer, or a mixture of two or more of them, soft polyvinyl chloride resin, Thermoplastic resins such as polyamide, polyamide elastomer, polyester, polyester elastomer, polyurethane, fluorocarbon resin, silicone rubber, latex rubber and the like can be used.

  Next, the stent 10 will be described. The stent 10 has a plurality of annular portions 20 aligned in the axial direction X of the balloon 130 and a link portion 30 connecting the annular portions 20 adjacent in the axial direction X, as shown in FIGS. And a drug layer 40.

  Each annular part 20 is formed of a wavelike linear component (wire) which is repeatedly folded back in a zigzag manner. The annular portion 20 includes a plurality of first bending portions 21 positioned on the distal end side in the axial direction X and a plurality of second bending portions 22 positioned on the proximal end side. The linear components are alternately bent at the first bend 21 and the second bend 22 toward the distal end side or the proximal end side. Thus, the annular portion 20 is formed in a wave shape.

  The annular portions 20 adjacent to each other in the axial direction X are integrally connected by the link portion 30. The adjacent annular parts 20 are connected by the link part 30 at at least one place (a plurality of places in the present embodiment) in the circumferential direction Y intersecting the axial direction X. The distal end portion of the link portion 30 is connected to the second bent portion 22 of the annular portion 20 located on the distal end side. The proximal end portion of the link portion 30 is connected to the first bent portion 21 of the annular portion 20 located on the proximal end side. The number of link portions 30 aligned in the circumferential direction Y is smaller than the number of first bent portions 21 aligned in the circumferential direction Y of one annular portion 20 and of the second bent portions 22 aligned in the circumferential direction Y. Less than the number. Therefore, the bending stiffness of the stent 10 at the position where the link portion 30 is provided in the axial direction X, ie, the position between the two annular portions 20 is higher than the bending stiffness of the stent 10 at the position where the annular portion 20 is provided. small.

  The two end annular portions 20A located at both ends in the axial direction X are connected to the adjacent annular portions 20 by end link portions 30A.

  The annular portion 20 and the link portion 30 have an outer surface 11, a side surface 12 and an inner surface 13. The outer surface 11 is located on the outer peripheral surface of the stent 10 which is generally cylindrical as a whole. The inner surface 13 is located on the inner circumferential surface of the stent 10 which is generally cylindrical as a whole. The side surface 12 joins the outer surface 11 and the inner surface 13 and is a surface substantially perpendicular to the outer surface 11 and the inner surface 13. Each link portion 30 and the first bent portion 21 and the second bent portion 22 connected to the link portion 30 constitute one connection area A. The connection area A includes two first side surfaces 12A and two second side surfaces 12B. Each of the two first side surfaces 12A is located between the two annular portions 20 connected to the link portion 30. Each of the two second side surfaces 12 </ b> B is located on the side opposite to the side connected to the link 30 of the respective annular parts 20 connected to the link 30. In the developed view, the angle θ1 formed by the first side surface 12A is an obtuse angle. The angle θ1 decreases as the stent 10 expands, as described later. Therefore, compressive stress acts on the first side surface 12A when the stent 10 expands. Further, in the developed view, the angle θ2 formed by the second side surface 12B is an acute angle. Therefore, tensile stress acts on the second side surface 12B when the stent 10 expands.

  At least one (a plurality of in the present embodiment) grooves 15 are formed on the outer surface 11 of each connection area A. The groove portion 15 is continuously formed without interruption from one first side surface 12A of the link portion 30 to the other first side surface 12A. In addition, although it is preferable that all the groove parts 15 of the link part 30 are formed continuously between two 1st side 12A, it is not limited to this. For example, a groove 15 of a part of the link 30 may be partially formed between the two first side surfaces 12A. In addition, if there is one or more link portions 30 in which the groove portion 15 is formed without interruption between the two first side surfaces 12A, the link portion 30 in which the groove portion 15 is not formed may be present.

  The plurality of grooves 15 formed in each link 30 are substantially parallel but may not be parallel. The groove portion 15 formed in the link portion 30 is linear, but may not be linear. The depth of the grooves 15 may be constant or different in each groove 15. Also, the depth of the groove 15 may be different depending on the groove 15.

  The groove 15 is not formed at all in the end link portion 30A connected to the end ring portion 20A. That is, the groove portion 15 is formed in the link portion 30 other than the end link portion 30A. In addition, the link part 30 in which the groove part 15 is not formed may exist in link parts 30 other than the end link part 30A. The groove portion 15 may be formed in the end link portion 30A.

  The stent 10 differs depending on the indwelling target site, but generally, the outer diameter at the time of expansion (at the time of non-contraction) is 1.5 to 30 mm, preferably 2.0 to 20 mm, and the thickness is 0.04 to 1.0 mm , Preferably 0.06 to 0.5 mm, and the length is 5 to 250 mm, preferably 8 to 200 mm.

  The stent 10 is made of a biocompatible material. Materials having biocompatibility are, for example, iron, titanium, aluminum, tin, tantalum or tantalum alloy, platinum or platinum alloy, gold or gold alloy, titanium alloy, nickel-titanium alloy, cobalt-based alloy, cobalt-chromium alloy, Stainless steel, zinc-tungsten alloy, niobium alloy, etc.

  The stent 10 is manufactured by removing non-constituting portions using a metal pipe. Thus, the annular portion 20 and the link portion 30 are integrally formed. The processing of the metal pipe can be performed by cutting (for example, mechanical polishing, laser cutting), electrical discharge processing, chemical etching, or the like, and may be performed by using these in combination. The groove 15 of the outer surface 11 of the stent 10 can be formed well by, for example, processing using a femtosecond laser.

  The drug layer 40 contains a drug and a drug carrier for carrying the drug. The drug layer 40 may be made of only a drug without containing a drug carrier. The drug layer 40 is coated on the outer surface 11 of the stent 10 except the first bend 21, the second bend 22 and the link 30. That is, the drug layer 40 is coated only on the outer surface 11 of the linear portion excluding the first bent portion 21 and the second bent portion 22 of the annular portion 20. The drug layer 40 is not coated on the first bent portion 21, the second bent portion 22 and the link portion 30. Therefore, the drug layer 40 does not cover the groove 15 formed in the link 30. The drug layer 40 may be coated on the link portion 30 of the stent 10. Also, the drug layer 40 may not be provided. The side of the stent 10 on which the drug layer 40 is provided may or may not be primed.

  As the drug, for example, anticancer drug, immunosuppressant, antibiotic, antirheumatic drug, antithrombotic drug, HMG-CoA reductase inhibitor, insulin resistance improving drug, ACE inhibitor, calcium antagonist, antihyperlipidemia Drugs, integrin inhibitors, antiallergic agents, antioxidants, GP IIb / IIIa antagonists, retinoids, flavonoids, carotenoids, lipid improvers, DNA synthesis inhibitors, tyrosine kinase inhibitors, antiplatelet drugs, antiinflammatory agents, living organisms Derived materials, interferon, nitric oxide production promoting substances can be mentioned.

  Next, the operation of the stent 10 according to the present embodiment will be described. Here, the case of treating a narrowed portion of a blood vessel will be described as an example.

  First, the balloon catheter 100 shown in FIG. 1 is prepared. The air in the balloon 130 and the dilation lumen 151 is extracted as much as possible, and the dilation fluid is substituted in the balloon 130 and the dilation lumen 151. At this time, the balloon 130 is in a folded state. In addition, the inside of the inner tube 160 is replaced with saline.

  Next, a guide wire is inserted into the guide wire lumen 161. Next, the guide wire and the balloon catheter 100 are inserted into the blood vessel from the inside of the sheath. Subsequently, the balloon catheter 100 is advanced while the guide wire is advanced, and the balloon 130 reaches the stenosis.

  Next, a predetermined amount of expansion fluid is injected from the proximal end opening 141 of the hub 140 using an indeflator, a syringe, or a pump. Thereby, the dilation fluid enters the inside of the balloon 130 through the dilation lumen 151. This causes the folded balloon 130 to expand. As a result, the cylindrical portion 131 of the balloon 130 spreads the narrowed portion and, as shown in FIG.

  Thereafter, the expansion fluid is sucked from the proximal end opening 141 and discharged. As a result, the balloon 130 is contracted to be in a folded state. Since the stent 10 is plastically deformed when expanded, it is placed in the narrowed portion in a spread state. Thereafter, the guide wire and the balloon catheter 100 are removed from the blood vessel. The stent 10 indwelled in a living lumen is entirely covered with endothelial cells over time.

  As described above, the stent 10 according to the first embodiment is annularly formed by the wire rod that is repeatedly folded back, and a plurality of annular portions 20 aligned in the axial direction X of the cylinder so as to form one cylinder. And the link portion 30 connecting the adjacent annular portions 20 with each other, the link portion 30 being adjacent to the outer surface 11 on the outer surface 11 located on the outer peripheral surface side of the stent 10 A continuous groove 15 is formed between the two side surfaces 12.

  The stent 10 configured as described above has high expansion holding power. Furthermore, since the continuous groove 15 is formed between the two side surfaces 12 on the side of the outer surface 11 where the stent 10 has a high contribution to the bending rigidity, the bending rigidity of the stent 10 is reduced and the flexibility is improved. Do. Therefore, the stent 10 can obtain high blood vessel followability, and can be deformed to follow various shapes of blood vessels. Further, since the groove 15 is formed on the outer surface 11 of the stent 10, the contact resistance of the stent 10 to the living tissue is increased. Therefore, when the stent 10 is expanded, the outer surface 11 of the stent 10 adheres well to the living tissue. Therefore, the stent 10 can be prevented from shifting from the desired position and shortening in the axial direction X (shortening). Therefore, the stent 10 can be placed at an appropriate position relative to the living body lumen.

  Further, the groove portion 15 is not formed in the end link portion 30A connected to either of the two end annular portions 20A located at both ends in the axial direction X of the stent 10. That is, the groove portion 15 is not formed in the end link portion 30A connected to the two end annular portions 20A located at both ends. For this reason, the rigidity of the both ends of the axial direction X of the stent 10 can be maintained high. Therefore, at the time of movement of the stent 10 in the axial direction X, it is possible to prevent the both ends of the stent 10 from coming in contact with biological tissue, other instruments, etc.

  Also, the side surface 12 has a first side surface 12A connecting two adjacent annular portions 20, and the groove portion 15 traverses between the two first side surfaces 12A. As a result, the stent 10 is easily bent at the link portion 30, and high flexibility can be obtained.

  Further, the link portion 30 is integrally formed with the annular portion 20. Thereby, the stent 10 exerts a higher expansion retention force.

  Further, the drug layer 40 is provided on the outer surface 11 of the stent 10, and the drug layer 40 is not provided at the site where the groove 15 is formed. As a result, the drug layer 40 does not exist at a site where the groove 15 is formed and is easily deformed. Therefore, the drug layer 40 can be prevented from dropping out of the stent 10.

  Further, the link portion 30 in which the groove portion 15 is formed is connected to the first bent portion 21 and the second bent portion 22. The first bent portion 21 and the second bent portion 22 constitute an end portion and project, so that the annular portion 20 is easily expanded to be in contact with the lumen wall. Therefore, when the stent 10 is expanded, the outer surface 11 of the link 30 in which the groove 15 is formed is pressed against the wall of a lumen such as a blood vessel. The link 30 is less slippery with respect to the lumen wall because the groove 15 is formed. Thus, the stent 10 can be deployed at an appropriate position relative to the biological lumen.

Second Embodiment
The stent 50 which concerns on 2nd Embodiment differs from 1st Embodiment only in the position in which the groove part 51 is formed, as shown in FIG. The parts having the same functions as those in the first embodiment are given the same reference numerals, and the description thereof is omitted.

  In the second embodiment, the groove 51 is continuously formed without interruption from one of the second side surfaces 12B sandwiching the connection area A to the other second side surface 12B. At least one (a plurality of in the present embodiment) grooves 51 are formed on the outer surface 11 of the connection area A. The groove 51 is formed on the outer surface 11 of the link 30, the first bent portion 21, and the second bent portion 22 constituting the connection area A. The groove 51 is formed substantially parallel to the axial direction X. The groove 51 may not be substantially parallel to the axial direction X.

  In the second embodiment, the side surface 12 has a second side surface 12B located on the side opposite to the side on which the link portion 30 is connected, of the two adjacent annular portions 20, and the groove portion 51 includes two It crosses between the 2nd side 12B. Since the groove 51 is continuously formed on the side of the outer surface 11 where the degree of contribution to the bending rigidity of the stent 50 is high, the bending rigidity of the stent 50 is reduced and high flexibility can be obtained. Further, in the link portion 30 having the groove portion 51, the angle of the wire forming the stent 50 with respect to the axial direction X of the stent 50 is easily changed. Therefore, the acute angle θ2 tends to increase, and the stent 50 can be easily expanded.

  The present invention is not limited to the above-described embodiment, and various modifications can be made by those skilled in the art within the technical concept of the present invention. For example, the link portion may have a link portion formed of a biodegradable material such as a biodegradable polymer material or a biodegradable metal material, and a link portion formed of a non-biodegradable material. Good. In this case, the groove portion is formed in the link portion formed of a non-biodegradable material. The biodegradable link is disassembled after the stent is deployed in vivo. Thereby, the stent can obtain high flexibility. Examples of biodegradable polymer materials include polylactic acid, polyglycolic acid, lactic acid-glycolic acid copolymer, polycaprolactone, lactic acid-caprolactone copolymer, glycolic acid-caprolactone copolymer, poly-γ-glutamic acid, etc. It is a biodegradable synthetic polymer material, or a biodegradable natural polymer material such as cellulose or collagen. The biodegradable metal material is, for example, magnesium, zinc or the like.

  The groove may be continuously formed without interruption from the first side surface 12A of the outer surface 11 of the connection area A to the second side surface 12B.

  Also, the stent may be formed of a helical wire. In this case, each annular portion is formed over 360 degrees in the circumferential direction Y, and the both ends are not connected. In the present embodiment, a form in which both ends are not connected is also included in the annular portion.

  Further, the shape of the link portion is not particularly limited. Therefore, the angle at which the extension direction of the link portion is inclined with respect to the axial direction X is not limited. Moreover, the link part may be bent at one or more places in the developed view. Also, the first bend and the second bend may be directly connected without separation. In this case, the overlapping portion of the first bend and the second bend can be interpreted as a link. Also, the groove may be formed not only in the link but also in the first bend and / or the second bend connected to the link. Also, the link portion may be connected to a position other than the bent portion of the annular portion. Also, a plurality of grooves may be formed to intersect at the outer surface of the link.

  In addition, the stent may be a self-expanding stent that expands by its own elastic force.

DESCRIPTION OF SYMBOLS 10, 50 Stent 11 Outer surface 12 Side 12 A 1st side 12 B 2nd side 13 Inner surface 15, 51 Groove 20 Annular part 20 A End annular part (annular part)
21 first bending portion 22 second bending portion 30 link portion 30A end link portion (link portion)
40 drug layers

Claims (7)

A plurality of annular portions formed in an annular shape by a wire member that is repeatedly folded back, and aligned in the axial center direction of the cylindrical body so as to form a single cylindrical body;
And a link portion connecting adjacent annular portions to each other.
The stent is characterized in that the link portion has an outer surface located on the outer circumferential surface side of the stent, and a continuous groove is formed across two side surfaces adjacent to the outer surface.   The stent according to claim 1, wherein the groove portion is not formed in the link portion connected to either of the two annular portions located at both axial ends of the stent.   The stent according to claim 1 or 2, wherein the link portion in which the groove portion is formed is connected to a bending bend portion of the annular portion. The side surface has a first side connecting two adjacent annular portions,
The stent according to any one of claims 1 to 3, wherein the groove crosses between the two first sides. The side surface has a second side surface of each of the two adjacent annular portions, which is located on the side opposite to the side to which the link portion is connected,
The stent according to any one of claims 1 to 4, wherein the groove crosses between the two second side surfaces.   The stent according to any one of claims 1 to 5, wherein the link portion is integrally formed with the annular portion.   The drug layer is provided on the outer surface of the stent, and the drug layer is not provided at the site where the groove portion is formed. Description stent.

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