JP2018079142A - Stent delivery system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stent delivery system that improves passage property of a stent while maintaining flexibility of the stent.SOLUTION: A stent delivery system 2 includes: a balloon catheter 3 having a balloon 32 capable of expanding and contracting; a stent 4 attached to the balloon 32 while being contracted, and expanding with expansion of the balloon 32; a plurality of wires 5 of which one ends 51 are fixed to a tip of the balloon catheter 3 disposed on a tip side relative to the stent 4, the wire 5 reducing a step 45 between a surface part 321 of the balloon 32 and a tip 41 of the stent 4.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a stent delivery system used to improve a stenosis or occlusion occurring in a living body lumen such as a blood vessel, a bile duct, a trachea, an esophagus, or a urethra.

Stents are placed in the stenosis or occlusion site to expand the stenosis or occlusion site and to secure the body lumen to treat various diseases caused by stenosis or occlusion of blood vessels or other biological lumens. Generally, it is a tubular medical device.
The stent is inserted into the body from outside the body. Therefore, when the stent is inserted into the body, the diameter of the stent is relatively small. Further, when the stent reaches the target stenosis or occlusion site, the diameter of the stent becomes relatively large. The stent expands at the target stenosis or occlusion site and holds the living body lumen expanded.

  In general, a stent is formed by processing a metal wire or a metal tube, and has a cylindrical shape. The stent is attached to a catheter or the like in a contracted state, inserted into a living body, expanded by a certain method at a target site, and maintained in a lumen shape by being in close contact with and fixed to the inner wall of the lumen. Stents are classified into self-expandable stents and balloon expandable stents according to function and placement method. The balloon expandable stent does not have an expansion function. After being inserted into the target site, the balloon expandable stent is expanded (plastically deformed) by expansion (expansion force) of the balloon disposed in the stent, and the inner surface of the target lumen It adheres to and is fixed.

  In the balloon expandable stent, the above-described stent expansion work is required. The balloon expandable stent is expanded by being plastically deformed by the expanding balloon, and is in close contact with the inner surface of the target lumen (for example, blood vessel). The balloon expandable stent has a high expansion maintenance force (radial force) due to plastic deformation. The purpose of stent placement is to prevent restenosis that occurs after a procedure such as PTCA and to reduce restenosis.

  Here, when the stent is delivered to the target site while being attached to the balloon, the distal end of the stent may be caught by the lesion. Alternatively, when the surgeon pulls the stent attached to the balloon into the guiding catheter in order to redo a procedure such as PTCA, the proximal end of the stent may be caught on the edge of the guiding catheter. As a result, the stent may fall out of the balloon in the living body lumen before the stent is placed at the target site.

  Patent Document 1 discloses a stent supply device in which a stent is fixed around a balloon by two covering and holding sleeves. The two covering holding sleeves described in Patent Document 1 cover the stent at each end or edge of the stent. When the balloon is inflated, it is released from the sleeve.

Japanese Patent No. 2935561

  However, in the stent supply device described in Patent Document 1, since the two covering holding sleeves cover the stent at each end of the stent, there is a radial step between the covering holding sleeve and the stent. . That is, two sheathing sleeves run over each end of the stent. Therefore, there is a possibility that the boundary portion (step portion) between the covering holding sleeve and the stent may be caught by the lesion or may be caught by the edge of the guiding catheter. Therefore, even when the two covering holding sleeves cover the stent at each end of the stent, the stent may fall out of the balloon in the living body lumen. In addition, the passage of the stent to the lesion and guiding catheter may be reduced. In addition, since the two sheathing sleeves cover the stent at each end of the stent, the flexibility of the stent mounted on the balloon may be compromised.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a stent delivery system that can improve the passage of the stent while maintaining the flexibility of the stent.

  According to the present invention, there is provided a balloon catheter having a balloon that can be expanded and contracted, a stent that is attached to the balloon in the contracted state and expands by the expansion of the balloon, and a distal side of the stent. A plurality of wires each having one end fixed to the distal end of the balloon catheter arranged to reduce a step between the surface of the balloon and the distal end of the stent; It is solved by a stent delivery system characterized by comprising.

  According to the said structure, the some wire by which one end part was fixed to the front-end | tip part of the balloon catheter arrange | positioned rather than the stent is provided. The wire reduces the step between the balloon surface and the stent tip. Therefore, when the wire is delivered to the target site in a state where the stent is attached to the balloon, the step portion between the surface portion of the balloon and the distal end portion of the stent can be prevented from being caught by the lesion. Therefore, the passage of the stent with respect to the lesion can be improved. Moreover, it can suppress that a stent falls from a balloon, and can suppress that the front-end | tip part of a stent turns up. Further, when the stent is delivered to the target site while being attached to the balloon, the wire extends in the axial direction of the stent and reduces the step between the surface portion of the balloon and the distal end portion of the stent. Therefore, the wire does not cover the entire circumference of the step portion between the surface portion of the balloon and the distal end portion of the stent. Thereby, it can suppress that the softness | flexibility of the stent with which the balloon was mounted | worn is impaired, and can maintain the softness | flexibility of a stent.

  Preferably, the other end opposite to the one end covers the distal end of the stent attached to the deflated balloon, and when the balloon is in the expanded state, the distal end of the stent. It is characterized by leaving.

  According to the said structure, the other edge part of a wire covers the front-end | tip part of the stent with which the balloon of the contracted state was mounted | worn. Therefore, the wire more reliably reduces the step between the balloon surface and the stent tip, and the step between the balloon surface and the stent tip is caught by the lesion. Can be suppressed more reliably. Therefore, the passage of the stent with respect to the lesion can be further improved. Moreover, it can suppress that a stent falls from a balloon, and can suppress that the front-end | tip part of a stent turns up. The other end of the wire is separated from the distal end of the stent when the balloon is in an expanded state. Therefore, it can avoid that a wire inhibits or suppresses expansion of a balloon.

Preferably, the other end is connected to the distal end of the stent by a polymer,
The other end connected by the polymer is released from the polymer when the balloon is in the expanded state.

  According to the above configuration, the other end portion of the wire covers the distal end portion of the stent attached to the deflated balloon and is connected to the distal end portion of the stent by the polymer. Therefore, in the state where the wire is connected to the distal end portion of the stent by the polymer, the step between the surface portion of the balloon and the distal end portion of the stent is more reliably reduced, and the surface portion of the balloon and the distal end of the stent are reduced. It can suppress more reliably that the level | step-difference part between a part is caught in a lesion | pathology. Therefore, the passage of the stent with respect to the lesion can be further improved and the stent can be prevented from falling off the balloon. Moreover, it can suppress that the front-end | tip part of a stent turns up. Also, the other end of the wire connected by the polymer is released from the polymer when the balloon is in an expanded state. Therefore, it can avoid that a polymer and a wire inhibit or suppress the expansion of a balloon.

  Preferably, the other end opposite to the one end is a ring body provided adjacent to a distal end side of the stent attached to the balloon in the contracted state, and is outside the stent. The ring body is connected to a ring body having the same outer diameter as the diameter, and the ring body moves from the position adjacent to the distal end side of the stent toward the distal end side when the balloon is in the expanded state.

  According to the said structure, the other edge part of a wire is connected to the ring body provided adjacent to the front end side of the stent with which the balloon of the contracted state was mounted | worn. The outer diameter of the ring body is the same as the outer diameter of the stent. Therefore, the ring body to which the other end of the wire is connected can more reliably reduce the step between the surface portion of the balloon and the distal end portion of the stent, and the surface portion of the balloon, the distal end portion of the stent, It is possible to more reliably suppress the stepped portion between and from being caught by the lesion. Therefore, the passage of the stent with respect to the lesion can be further improved. Moreover, it can suppress that a stent falls from a balloon, and can suppress that the front-end | tip part of a stent turns up. Further, when the balloon is in an expanded state, the ring body moves from the position adjacent to the distal end side of the stent toward the distal end side. Therefore, it can avoid that a ring body and a wire inhibit or suppress the expansion of a balloon.

  Preferably, the wire is a first wire, and a plurality of second wires each having one end fixed to a proximal side portion of the balloon catheter disposed proximally than the stent, A second wire for reducing a step between the surface portion of the balloon and the proximal end portion of the stent is further provided.

  According to the above configuration, the plurality of second wires each having one end fixed to the proximal end portion of the balloon catheter disposed on the proximal end side with respect to the stent are further provided. The second wire reduces the step between the surface portion of the balloon and the proximal end portion of the stent. Therefore, when the second wire is pulled out with the stent mounted on the balloon, the stepped portion between the surface portion of the balloon and the proximal end portion of the stent is caught on the edge of the guiding catheter. Can be suppressed. Therefore, the passage of the stent with respect to the guiding catheter can be improved. Moreover, it can suppress that a stent falls from a balloon, and can suppress that the proximal end part of a stent is turned up. Further, when the stent is pulled out while being attached to the balloon, the second wire extends in the axial direction of the stent and reduces a step between the surface portion of the balloon and the proximal end portion of the stent. For this reason, the second wire does not cover the entire circumference of the step portion between the surface portion of the balloon and the proximal end portion of the stent. Thereby, it can suppress that the softness | flexibility of the stent with which the balloon was mounted | worn is impaired, and can maintain the softness | flexibility of a stent.

  Preferably, the other end of the second wire opposite to the one end covers the proximal end of the stent attached to the deflated balloon, and the balloon is in the expanded state. It is separated from the proximal end portion of the stent.

  According to the above configuration, the other end of the second wire covers the proximal end of the stent attached to the deflated balloon. Therefore, the second wire more reliably reduces the step between the surface portion of the balloon and the proximal end portion of the stent, and the step portion between the surface portion of the balloon and the proximal end portion of the stent is reduced. It can suppress more reliably that it is caught in the edge of a guiding catheter. Therefore, the passage of the stent with respect to the guiding catheter can be further improved. Moreover, it can suppress that a stent falls from a balloon, and can suppress that the proximal end part of a stent is turned up. The other end of the second wire is separated from the proximal end of the stent when the balloon is in an expanded state. Therefore, it can be avoided that the second wire inhibits or suppresses the expansion of the balloon.

  Preferably, the other end portion of the second wire is connected to the proximal end portion of the stent by a polymer, and the other end portion of the second wire connected by the polymer has the balloon in the expanded state. Then, the polymer is released from the polymer.

  According to the above configuration, the other end portion of the second wire covers the proximal end portion of the stent attached to the deflated balloon and is connected to the proximal end portion of the stent by the polymer. Therefore, in the state where the second wire is connected to the proximal end portion of the stent with the polymer, the step between the surface portion of the balloon and the proximal end portion of the stent is more reliably reduced, and the surface portion of the balloon Further, the stepped portion between the proximal end portion of the stent and the edge portion of the guiding catheter can be more reliably suppressed. Therefore, the passage of the stent with respect to the guiding catheter can be further improved and the stent can be prevented from dropping from the balloon. Moreover, it can suppress that the proximal end part of a stent turns up. Also, the other end of the second wire connected by the polymer is released from the polymer when the balloon is in an expanded state. Therefore, it can be avoided that the polymer and the second wire inhibit or suppress the expansion of the balloon.

  Preferably, the ring body is a first ring body, and the other end of the second wire opposite to the one end is a proximal end of the stent attached to the balloon in the contracted state. A second ring body provided adjacent to the side and connected to a second ring body having an outer diameter equal to the outer diameter of the stent, and the second ring body is It moves from the position adjacent to the proximal end side of the stent toward the proximal end side.

  According to the said structure, the other edge part of a 2nd wire is connected to the 2nd ring body provided adjacent to the base end side of the stent with which the balloon of the contracted state was mounted | worn. The outer diameter of the second ring body is the same as the outer diameter of the stent. Therefore, the second ring body, to which the other end of the second wire is connected, more reliably reduces the step between the surface portion of the balloon and the proximal end portion of the stent, It can suppress more reliably that the level | step-difference part between the base end part of a stent is caught in the edge part of a guiding catheter. Therefore, the passage of the stent with respect to the guiding catheter can be further improved. Moreover, it can suppress that a stent falls from a balloon, and can suppress that the proximal end part of a stent is turned up. Further, the second ring body moves from the position adjacent to the proximal end side of the stent toward the proximal end side when the balloon is in an expanded state. Therefore, it can avoid that a 2nd ring body and a 2nd wire inhibit or suppress expansion | swelling of a balloon.

  ADVANTAGE OF THE INVENTION According to this invention, the stent delivery system which can improve the passage property of a stent can be provided, maintaining the softness | flexibility of a stent.

It is a front view showing the stent delivery system concerning the embodiment of the present invention. It is a fragmentary sectional view of the tip part of the stent delivery system concerning this embodiment. It is a fragmentary sectional view explaining an operation of a stent delivery system concerning this embodiment. It is a top view showing the 1st specific example of the wire of this embodiment. It is a top view showing the 2nd specific example of the wire of this embodiment. It is a top view showing the 3rd specific example of the wire of this embodiment. It is a top view showing the 4th specific example of the wire of this embodiment. It is a top view showing the 5th example of a wire of this embodiment. It is a top view showing the 6th specific example of the wire of this embodiment.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.
The embodiments described below are preferable specific examples of the present invention, and thus various technically preferable limitations are given. However, the scope of the present invention is particularly limited in the following description. Unless otherwise stated, the present invention is not limited to these embodiments. Moreover, in each drawing, the same code | symbol is attached | subjected to the same component and detailed description is abbreviate | omitted suitably.

FIG. 1 is a front view showing a stent delivery system according to an embodiment of the present invention.
FIG. 2 is a partial cross-sectional view of the distal end portion of the stent delivery system according to the present embodiment.
FIG. 3 is a partial cross-sectional view for explaining the operation of the stent delivery system according to the present embodiment.
For convenience of explanation, in FIGS. 1 to 9, the right side is referred to as a “base end” and the left side is referred to as a “tip”. In FIG. 3, the stent 4 is omitted.

  The stent delivery system 2 according to the embodiment of the present invention includes a balloon catheter 3 having a balloon 32 and a stent 4 attached to the balloon 32. The balloon catheter 3 has a tube-shaped shaft main body 31 and a foldable and expandable balloon 32 provided at the distal end of the shaft main body 31. That is, the balloon 32 is provided at the distal end portion of the shaft main body 31 so that it can be expanded and contracted.

  The stent 4 is attached to the balloon 32 so as to encapsulate the balloon 32 in a contracted state, and expands by expansion of the balloon 32. The stent 4 is a so-called balloon-expandable stent that has a diameter for insertion into a lumen in a living body and is expandable when a force spreading in the radial direction from the inside of the tubular body is applied.

  In the stent delivery system 2 according to the present embodiment, as shown in FIGS. 2 and 3, the shaft main body 31 has a guide wire lumen 314. One end of the guide wire lumen 314 is open at the tip of the shaft main body 31. Further, the other end of the guide wire lumen 314 is opened in the middle or the base end of the shaft main body 31.

  More specifically, the shaft main body 31 includes an inner tube 311, an outer tube 312, and a hub 313. As shown in FIG. 3, the inner tube 311 is a tube body having a guide wire lumen 314 for inserting a guide wire W (see FIG. 1). The length of the inner tube 311 is 100 to 1500 mm, more preferably 150 to 500 mm. The outer diameter of the inner tube 311 is 0.1 to 1.0 mm, more preferably 0.3 to 0.7 mm. The wall thickness of the inner tube 311 is 10 to 250 μm, more preferably 20 to 100 μm. The inner tube 311 is inserted into the outer tube 312. The distal end portion of the inner tube 311 protrudes more distally than the outer tube 312.

  A balloon expansion lumen 315 is formed between the outer surface of the inner tube 311 and the inner surface of the outer tube 312, and has a sufficient volume.

  The outer tube 312 is a tube body in which the inner tube 311 is inserted. The distal end of the outer tube 312 is located at a portion slightly retracted from the distal end of the inner tube 311. The length of the outer tube 312 is 100 to 2500 mm, and more preferably 250 to 2000 mm. The outer diameter of the outer tube 312 is 0.5 to 1.5 mm, more preferably 0.7 to 1.1 mm. The wall thickness of the outer tube 312 is 25 to 200 μm, more preferably 50 to 100 μm.

  In the stent delivery system 2 according to the present embodiment, the outer tube 312 includes a distal end side outer tube 312a and a proximal end side outer tube 312b. The distal end side outer tube 312a and the proximal end side outer tube 312b are joined to each other. The distal outer tube 312a is tapered in the vicinity of the junction between the distal outer tube 312a and the proximal outer tube 312b. Therefore, the diameter of the distal outer tube 312a on the distal end side with respect to the tapered portion is smaller than the diameter of the proximal outer tube 312b on the proximal end side with respect to the tapered portion.

  The outer diameter of the small-diameter portion (the portion closer to the distal end than the tapered portion) of the distal end side outer tube 312a is 0.50 to 1.5 mm, preferably 0.60 to 1.1 mm. Moreover, the outer diameter of the base end side outer tube 312b is 0.75 to 1.5 mm, preferably 0.9 to 1.1 mm.

  In the stent delivery system 2 according to the present embodiment, the inner tube 311 is provided to extend inside the balloon 32 and the distal end side outer tube 312a. The proximal end portion of the inner tube 311 is fixed in a liquid-tight manner in the middle of the distal end side outer tube 312a by an adhesive or heat fusion. The proximal end of the inner tube 311 opens in the middle of the distal end side outer tube 312a, and is provided as a guide wire port 313a. Therefore, as shown in FIG. 1, the guide wire W inserted from the distal end of the inner tube 311 is guided from the distal end side to the proximal end side of the guide wire lumen 314 of the inner tube 311 and is guided from the guide wire port 313a. It is led out of the stent delivery system 2. That is, the stent delivery system 2 according to the present embodiment is configured as a so-called “rapid exchange type” stent delivery system.

  The material for forming the inner tube 311 and the outer tube 312 is preferably a material having a certain degree of flexibility. For example, polyolefin (for example, polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, etc.) Further, thermoplastic resins such as polyvinyl chloride, polyamide elastomer and polyurethane, silicone rubber, latex rubber and the like can be used. The material for forming the inner tube 311 and the outer tube 312 is preferably the thermoplastic resin described above, and more preferably polyolefin.

  The balloon 32 is foldable, and is folded on the outer periphery of the inner tube 311 when not expanded. The balloon 32 has an expandable portion that exhibits a cylindrical portion (preferably, a cylindrical portion) having substantially the same diameter so that the attached stent 4 can be expanded. The substantially cylindrical portion may not be a complete cylinder but may be a polygonal column.

  The balloon 32 has a distal end side joint portion 32a and a proximal end side joint portion 32b. The distal end side joint portion 32 a is fixed at a position slightly proximal to the distal end of the inner tube 311. Specifically, the distal end side joint portion 32a is fixed to the inner tube 311 in a liquid-tight manner by an adhesive or heat fusion. The proximal end joint portion 32 b is fixed to the distal end of the outer tube 312. Specifically, the proximal end side joining portion 32b is liquid-tightly fixed to the distal end of the outer tube 312 with an adhesive or heat fusion. Accordingly, the balloon 32 is liquid-tightly fixed to the inner tube 311 and the outer tube 312 by an adhesive or heat fusion. The balloon 32 communicates with the balloon expansion lumen 315 in the vicinity of the proximal end portion. Moreover, in the balloon 32 of this embodiment, the space | interval between the expandable part and the front end side junction part 32a and the base end side junction part 32b is formed in the taper shape.

  The balloon 32 has an expansion space 32 c formed between the inner surface of the balloon 32 and the outer surface of the inner tube 311. The base end portion of the expansion space 32c communicates with the balloon expansion lumen 315 on the entire circumference. Thus, the proximal end of the balloon 32 communicates with the balloon expansion lumen 315 having a relatively large volume. Therefore, the expansion fluid can be reliably injected from the balloon expansion lumen 315 into the balloon 32.

  As a material for forming the balloon 32, a material having a certain degree of flexibility is preferable. For example, polyolefin (for example, polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, cross-linked ethylene-vinyl acetate). Copolymer), polyvinyl chloride, polyamide, polyamide elastomer, polyurethane, polyester (for example, polyethylene terephthalate), polyester elastomer, polyarylene sulfide (for example, polyphenylene sulfide), thermoplastic resin, silicone rubber, latex rubber, etc. Can be used. In particular, the forming material of the balloon 32 is preferably a stretchable material. The balloon 32 is preferably biaxially stretched having high strength and expansion force.

  The outer diameter of the cylindrical portion (expandable portion) of the balloon 32 when the balloon 32 is expanded is 2 to 4 mm, preferably 2.5 to 3.5 mm. The length of the balloon 32 is 10 to 50 mm, preferably 20 to 40 mm. The outer diameter of the distal end side joint portion 32a is 0.9 to 1.5 mm, preferably 1 to 1.3 mm. The length of the distal end side joint portion 32a is 1 to 5 mm, preferably 1 to 3 mm. Moreover, the outer diameter of the base end side joining part 32b is 1-1.6 mm, Preferably it is 1.1-1.5 mm. The length of the base end side joining portion 32b is 1 to 5 mm, preferably 2 to 4 mm.

  The stent delivery system 2 according to the present embodiment has two X-ray contrast members 316 and 317 as shown in FIGS. The X-ray contrast-enhancing members 316 and 317 are fixed to the outer surface of the shaft main body 31 at positions corresponding to both ends of the cylindrical portion (expandable portion) when the balloon 32 is expanded. Note that the two X-ray contrast members may be fixed to the outer surface of the shaft main body 31 (in the present embodiment, the inner tube 311) at the positions corresponding to both ends of the center portion of the stent 4. Further, a single X-ray contrast member may be fixed to the outer surface of the shaft main body 31 at a position that becomes the central portion of the stent.

  The X-ray contrast-enhancing members 316 and 317 are preferably a ring-shaped member having a predetermined length or a member obtained by winding a linear member in a coil shape. The material for forming the X-ray contrast members 316 and 317 is preferably, for example, gold, platinum, tungsten, an alloy thereof, or a silver-palladium alloy.

  A linear rigidity imparting body (not shown) may be inserted between the inner tube 311 and the outer tube 312 (within the balloon expansion lumen 315). The rigidity imparting body prevents extreme bending of the shaft main body portion 31 of the stent delivery system 2 at the bent portion without significantly reducing the flexibility of the stent delivery system 2, and prevents the distal end portion of the stent delivery system 2 from being bent. Easy to push. The diameter of the distal end portion of the rigidity imparting body is preferably smaller than the diameter of other portions by a method such as polishing. In addition, it is preferable that the end of the small diameter portion of the rigidity imparting body extends to the vicinity of the end of the outer tube 312. The rigidity imparting body is preferably a metal wire, and is preferably an elastic metal such as stainless steel having a wire diameter of 0.05 to 1.50 mm, preferably 0.10 to 1.00 mm, a superelastic alloy, etc. Is a high-strength stainless steel for springs and a superelastic alloy wire.

  In the stent delivery system 2 according to the present embodiment, as shown in FIG. 1, a hub 313 is fixed to the proximal end. The hub 313 has an injection port 313 b that is fixed to the outer tube 312 and communicates with the balloon expansion lumen 315.

  As a material for forming the hub 313, a thermoplastic resin such as polycarbonate, polyamide, polysulfone, polyarylate, or methacrylate-butylene-styrene copolymer can be suitably used. The structure of the stent delivery system 2 is not limited to the above structure. For example, the stent delivery system 2 is configured as an “over-the-wire type” stent delivery system in which the guide wire lumen 314 is formed over the entire length of the stent delivery system 2 and the guide wire W is led out from the proximal end of the hub 313. Also good.

  The stent 4 is attached to the balloon 32 so as to encapsulate the balloon 32. The stent 4 is manufactured by processing, for example, a metal pipe having an inner diameter smaller than that of the expanded stent 4 and an inner diameter larger than the outer diameter of the folded balloon 32. Then, the balloon 32 is inserted into the manufactured stent 4, and a uniform force is applied to the outer surface of the stent 4 inward to reduce the diameter, thereby forming the product-state stent 4. That is, the stent 4 is completed by compression mounting on the balloon 32.

  The stent 4 is formed in a substantially tubular body, has a diameter for insertion into a living body lumen, and expands when a force spreading radially from the inside of the stent 4 is applied. The stent 4 is formed of, for example, a linear body having a predetermined line width.

  The non-expanded diameter (outer diameter) of the stent 4 is preferably about 0.8 to 1.8 mm, and more preferably 0.9 to 1.4 mm. The diameter (outer diameter) of the stent 4 during molding (before compression) is preferably about 1.5 to 3.5 mm, and more preferably 2.0 to 3.0 mm. The length of the stent 4 when not expanded is preferably about 9 to 40 mm.

  The thickness of the stent 4 is preferably about 0.05 to 0.15 mm, and particularly preferably 0.08 to 0.12 mm. In the case where the stent 4 is formed of a linear body, the line width of the linear body constituting the stent 4 is preferably about 0.07 to 0.15 mm, and particularly 0.08 to 0.13 mm. Is preferred.

  The material for forming the stent 4 is not particularly limited. Examples of the material for forming the stent 4 include metals. When the stent 4 is made of metal, the material for forming the stent 4 is preferably a material having a certain degree of biocompatibility, such as stainless steel, tantalum or tantalum alloy, platinum or platinum alloy, gold or gold alloy. And cobalt base alloys such as cobalt chrome alloys. Further, after the shape of the stent 4 is produced, noble metal plating (gold, platinum) may be applied. As stainless steel, SUS316L having the most corrosion resistance is suitable.

  The stent 4 is preferably chamfered. Examples of the chamfering method for the stent 4 include a method in which the stent 4 is formed into a final shape and then chemically polished, electrolytically polished, or mechanically polished.

  Furthermore, it is preferable to perform annealing after producing the final shape of the stent 4. By performing the annealing, the flexibility and plasticity of the entire stent 4 are improved, and the indwellability in the bent blood vessel is improved. Compared with the case where the annealing is not performed, the force to restore the shape before expansion after the stent 4 is expanded, particularly the force to return to the linear shape that is developed when the stent 4 is expanded at the bent blood vessel site is reduced. . In addition, physical stimulation applied to the bent blood vessel inner wall is reduced. Thereby, the factor of restenosis can be reduced. Annealing is performed by heating to 900 to 1200 ° C. in an inert gas atmosphere (for example, a mixed gas of nitrogen and hydrogen) and then slowly cooling so that an oxide film is not formed on the surface of the stent 4. It is preferable.

  The entire outer surface of the stent 4 or a part of the outer surface may be coated with a polymer containing a physiologically active substance. In this case, the polymer containing the physiologically active substance preferably covers the entire outer surface of the stent 4, but may partially cover the outer surface of the stent 4.

  The polymer containing a physiologically active substance is preferably a biodegradable polymer. The biodegradable polymer is not particularly limited as long as it is enzymatically or non-enzymatically degraded in vivo and the degradation product does not show toxicity. For example, polylactic acid, polyglycolic acid, polylactic acid-polyglycol Acid copolymer, polycaprolactone, polylactic acid-polycaprolactone copolymer, polyorthoester, polyphosphazene, polyphosphate ester, polyhydroxybutyric acid, polymalic acid, poly α-amino acid, collagen, gelatin, laminin, heparan sulfate, fibronectin Vitronectin, chondroitin sulfate, hyaluronic acid, polypeptide, chitin, chitosan and the like can be used.

  The outer surface of the stent 4 may be subjected to a surface treatment in order to enhance the adhesion with the polymer. As the surface treatment, there is a method of coating the surface with a material having high affinity as a primer. Although various materials can be used as the primer material, the most preferable one is a silane coupling agent having a hydrolyzable group and an organic functional group. The silanol group generated by the decomposition of the hydrolyzable group (for example, alkoxy group) of the silane coupling agent is bonded to the surface of the joining portion (free end portion) of the metal easily deformable portion by chemical bonding or the like. The organic functional group (for example, epoxy group, amino group, mercapto group, vinyl group, methacryloxy group) of the silane coupling agent can be bonded to a polymer containing a physiologically active substance by a chemical bond. Specific examples of the silane coupling agent include γ-aminopropylethoxysilane and γ-glycidoxypropylmethyldimethoxysilane. Examples of primer materials other than silane coupling agents include organic titanium coupling agents, aluminum coupling agents, chromium coupling agents, organic phosphoric acid coupling agents, organic vapor deposition films such as polyparaxylene, and cyanoacrylates. Adhesives, polyurethane-based paste resins, and the like. In addition, a primer does not necessarily need to be used.

  The bioactive substances contained in the polymer include substances that suppress intimal thickening, anticancer agents, immunosuppressive agents, antibiotics, antirheumatic agents, antithrombotic agents, HMG-CoA reductase inhibitors, ACE inhibitors, calcium antagonists Antihyperlipidemic agent, anti-inflammatory agent, integrin inhibitor, antiallergic agent, antioxidant, GPIIbIIIa antagonist, retinoid, flavonoid and carotenoid, lipid improver, DNA synthesis inhibitor, tyrosine kinase inhibitor, antiplatelet Drugs, vascular smooth muscle growth inhibitors, anti-inflammatory drugs, biological materials, interferons, NO production promoters, epithelial cells generated by genetic engineering, and the like are used. And you may use 2 or more types of mixtures, such as said substance.

  As the anticancer agent, for example, vincristine, vinblastine, vindesine, irinotecan, pirarubicin, paclitaxel, docetaxel, methotrexate and the like are preferable. As the immunosuppressant, for example, sirolimus, tacrolimus, azathioprine, cyclosporine, cyclophosphamide, mycophenolate mofetil, gusperimus, mizoribine and the like are preferable. As the antibiotic, for example, mitomycin, adriamycin, doxorubicin, actinomycin, daunorubicin, idarubicin, pirarubicin, aclarubicin, epirubicin, pepromycin, dinostatin styramer and the like are preferable. As the anti-rheumatic agent, for example, methotrexate, sodium thiomalate, penicillamine, lobenzalit and the like are preferable. As the antithrombotic drug, for example, heparin, aspirin, antithrombin preparation, ticlopidine, hirudin and the like are preferable. As the HMG-CoA reductase inhibitor, for example, cerivastatin, cerivastatin sodium, atorvastatin, nisvastatin, itavastatin, fluvastatin, fluvastatin sodium, simvastatin, lovastatin, pravastatin and the like are preferable. As the ACE inhibitor, for example, quinapril, perindopril erbumine, trandolapril, cilazapril, temocapril, delapril, enalapril maleate, lisinopril, captopril and the like are preferable. As the calcium antagonist, for example, nifedipine, nilvadipine, diltiazem, benidipine, nisoldipine and the like are preferable. As the antihyperlipidemic agent, for example, probucol is preferable. As the antiallergic agent, for example, tranilast is preferable. As the retinoid, for example, as all-trans retinoic acid, flavonoid and carotenoid, for example, catechins, particularly epigallocatechin gallate, anthocyanins, proanthocyanidins, lycopene, β-carotene and the like are preferable. As the tyrosine kinase inhibitor, for example, genistein, tyrphostin, arbustatin and the like are preferable. As the anti-inflammatory agent, for example, steroids such as dexamethasone and prednisolone are preferable. As the biological material, for example, EGF (epidermal growth factor), VEGF (vascular endothelial growth factor), HGF (hepatocyte growth factor), PDGF (platelet derived growth factor), bFGF (basic fibroblast growth factor) and the like are preferable.

  As shown in FIG. 2, a plurality of wires 5 are provided at the distal end portion of the balloon catheter 3. One end 51 of the wire 5 is fixed to the distal end of the balloon catheter 3 disposed on the distal side of the stent 4. In the present embodiment, one end portion 51 of the wire 5 is fixed to the outer surface of the distal end portion of the inner tube 311 with an adhesive or heat fusion.

  It should be noted that one end 51 of the wire 5 only needs to be fixed to the distal end of the balloon catheter 3 disposed on the distal side of the stent 4, and is fixed to the distal end of the inner tube 311. It is not limited. For example, the tip of the inner tube 311 may be provided with a tip that is made of a material that is more flexible than the material of the shaft body 31. One end 51 of the wire 5 may be fixed to the tip. Alternatively, one end portion 51 of the wire 5 may be fixed to the distal end side joint portion 32 a of the balloon 32 disposed on the distal end side with respect to the stent 4. In the present specification, the “tip portion of the balloon catheter 3” refers to a portion of the balloon catheter 3 that is disposed on the tip side of the stent 4. The “tip portion of the balloon catheter” of the present invention corresponds to, for example, the tip portion of the inner tube 311, the tip tip provided at the tip portion of the inner tube 311, or the tip side joint portion 32 a of the balloon 32. In the following description, a case where one end portion 51 of the wire 5 is fixed to the distal end portion of the inner tube 311 is taken as an example.

  The material for forming the wire 5 is not particularly limited. Examples of the material for forming the wire 5 include metal. The material for forming the wire 5 is preferably a material having a certain degree of biocompatibility. For example, stainless steel, tantalum or tantalum alloy, platinum or platinum alloy, gold or gold alloy, cobalt base alloy such as cobalt chrome alloy, nickel titanium, etc. Examples thereof include nickel base alloys such as alloys. Alternatively, the material for forming the wire 5 may be the biodegradable polymer described above.

  Here, when the stent is delivered to a target site such as a stenosis site or an occlusion site while being attached to a balloon, the distal end portion of the stent may be caught by a lesion. Alternatively, when the surgeon pulls the stent attached to the balloon into the guiding catheter in order to redo a procedure such as PTCA, the proximal end of the stent may be caught on the edge of the guiding catheter. As a result, the stent may fall out of the balloon in the living body lumen before the stent is placed at the target site. Also, the passage of the stent to the lesion and guiding catheter may be reduced. For example, in order to prevent the stent from falling off the balloon, when the entire circumference of both ends of the stent is covered with a sleeve or the like, there is a new problem that the flexibility of the stent attached to the balloon is impaired. Arise.

  In contrast, in the stent delivery system 2 according to the present embodiment, a plurality of wires 5 are provided at the distal end portion of the balloon catheter 3 as shown in FIG. One end 51 of the wire 5 is fixed to the distal end of the balloon catheter 3 disposed on the distal side of the stent 4. The plurality of wires 5 reduce the step 45 between the surface portion 321 of the balloon 32 and the distal end portion 41 of the stent 4.

  Therefore, when the wire 5 is delivered to the target site with the stent 4 mounted on the balloon 32, the step 45 between the surface portion 321 of the balloon 32 and the distal end portion 41 of the stent 4 is It can suppress being caught in a lesion. Therefore, the passage of the stent 4 with respect to the lesion can be improved. Moreover, it can suppress that the stent 4 falls from the balloon 32, and can suppress that the front-end | tip part 41 of the stent 4 is turned up. “The distal end 41 of the stent 4 is turned up” means that the distal end 41 of the stent 4 does not fall off the balloon 32 due to, for example, being caught by a lesion, but the outer end of the distal end 41 of the stent 4 is not removed. This means that the diameter is larger than the outer diameter of the central portion of the stent 4 or the distal end portion 41 of the stent 4 is folded. When the stent 4 is delivered to the target site while being attached to the balloon 32, the wire 5 extends in the direction of the axis 49 of the stent 4, and the surface portion 321 of the balloon 32, the distal end portion 41 of the stent 4, and the like. , The step 45 is reduced. Therefore, the wire 5 does not cover the entire circumference of the step 45 between the surface portion 321 of the balloon 32 and the distal end portion 41 of the stent 4. Thereby, it can suppress that the softness | flexibility of the stent 4 with which the balloon 32 was mounted | worn is impaired, and the softness | flexibility of the stent 4 can be maintained.

Next, a specific example of the wire of this embodiment will be described with reference to the drawings.
FIG. 4 is a plan view illustrating a first specific example of the wire of the present embodiment.
FIG. 4A is a plan view showing a state before the stent 4 is expanded. FIG. 4B is a plan view showing a state after the stent 4 is expanded. FIG.4 (c) is a top view showing a state when a balloon catheter is extracted.

  As described above with reference to FIG. 2, one end 51 of the wire 5 is fixed to the distal end of the balloon catheter 3. On the other hand, in this specific example, as shown in FIG. 4A, the other end 52 of the wire 5 opposite to the one end 51 of the wire 5 is attached to the deflated balloon 32. The distal end portion 41 of the stent 4 is covered. Specifically, when the stent 4 is delivered to the target site while being attached to the balloon 32, the wire 5 is in a state where the other end 52 is located on the proximal side relative to the one end 51. It extends in the direction of the axis 49 (see FIG. 2) of the stent 4 and covers the distal end portion 41 of the stent 4. The other end 52 of the wire 5 is not fixed to the stent 4 or the balloon 32.

  Thereby, the wire 5 more reliably reduces the step 45 between the surface portion 321 of the balloon 32 and the tip portion 41 of the stent 4, and the surface portion 321 of the balloon 32, the tip portion 41 of the stent 4, and the like. It can suppress more reliably that the part of the level | step difference 45 between is caught in a lesion | pathological-change. Therefore, the passage of the stent 4 with respect to the lesion can be further improved. Moreover, it can suppress that the stent 4 falls from the balloon 32, and can suppress that the front-end | tip part 41 of the stent 4 is turned up.

  As shown in FIG. 4B, the other end 52 of the wire 5 does not reach the distal end 41 of the expanded stent 4, so that the distal end of the stent 4 when the balloon 32 is expanded. Leave 41. Thereby, it can avoid that the wire 5 inhibits or suppresses expansion of the balloon 32.

  4C, the other end 52 of the wire 5 is not fixed to the stent 4 or the balloon 32. Therefore, when the balloon catheter 3 is removed, the wire 5 The end 52 extends in the direction of the axis 49 of the stent 4 in a state where the end 52 is located on the distal end side with respect to the one end 51. That is, the extending direction of the wire 5 can be reversed between when the balloon catheter 3 is inserted into the living body and when the balloon catheter 3 is removed from the body. Thereby, it can suppress that the wire 5 overlaps with the stent 4 indwelled in the target site | part, or is caught, and can suppress that the indwelling position of the stent 4 shifts | deviates. The balloon catheter 3 to which the wire 5 is attached is pulled out of the body through the inside of the tubular body of the expanded stent 4.

FIG. 5 is a plan view illustrating a second specific example of the wire of the present embodiment.
FIG. 5A is a plan view showing a state before the stent 4 is expanded. FIG. 5B is a plan view showing a state after the stent 4 is expanded.

  In this specific example, as shown in FIG. 5A, the other end portion 52 of the wire 5 covers the distal end portion 41 of the stent 4 attached to the deflated balloon 32 and the distal end portion of the stent 4. 41 is connected to polymer 41 by polymer 53. The polymer 53 is preferably a biodegradable polymer. Examples of the biodegradable polymer include the biodegradable polymers described above with reference to FIGS.

  Therefore, in the state where the wire 5 is connected to the distal end portion 41 of the stent 4 by the polymer 53, the step 45 between the surface portion 321 of the balloon 32 and the distal end portion 41 of the stent 4 is more reliably reduced, It can suppress more reliably that the part of the level | step difference 45 between the surface part 321 of the balloon 32 and the front-end | tip part 41 of the stent 4 is caught by a lesion. Therefore, the passage of the stent 4 with respect to the lesion can be further improved, and the stent 4 can be prevented from falling off the balloon 32. Moreover, it can suppress that the front-end | tip part 41 of the stent 4 is turned up.

  The connection strength by the polymer 53 is lower than the connection strength by an adhesive or heat fusion. Therefore, as shown in FIG. 5B, the other end 52 of the wire 5 connected by the polymer 53 is released from the polymer 53 when the balloon 32 is in an expanded state. Thereby, it can avoid that the polymer 53 and the wire 5 inhibit or suppress the expansion of the balloon 32.

FIG. 6 is a plan view illustrating a third specific example of the wire of the present embodiment.
FIG. 6A is a plan view showing a state before the stent 4 is expanded. FIG. 6B is a plan view showing a state after the stent 4 is expanded.

  In this specific example, as shown in FIG. 6A, the other end 52 of the wire 5 is connected to the ring body 54. The ring body 54 is formed so as to surround the deflated balloon 32, and is provided adjacent to the distal end side of the stent 4 attached to the deflated balloon 32. The material for forming the ring body 54 is not particularly limited. Examples of the material for forming the ring body 54 include metals. Examples of the material for forming the ring body 54 include the same metal as that of the wire 5 described above with reference to FIG. Alternatively, the material for forming the ring body 54 may be, for example, the biodegradable polymer described above with reference to FIGS. The outer diameter of the ring body 54 is the same as the outer diameter of the stent 4.

  Therefore, the ring body 54 to which the other end portion 52 of the wire 5 is connected can more reliably reduce the step 45 between the surface portion 321 of the balloon 32 and the distal end portion 41 of the stent 4. It can suppress more reliably that the part of the level | step difference 45 between the surface part 321 and the front-end | tip part 41 of the stent 4 is caught by a lesion. Therefore, the passage of the stent 4 with respect to the lesion can be further improved. Moreover, it can suppress that the stent 4 falls from the balloon 32, and can suppress that the front-end | tip part 41 of the stent 4 is turned up.

  Then, as illustrated in FIG. 6B, the ring body 54 moves from the position adjacent to the distal end side of the stent 4 toward the distal end side when the balloon 32 is in an expanded state. When the space between the expandable portion and the distal end side joint portion 32a is formed in a tapered shape as in the balloon 32 of the present embodiment, the ring body 54 has the stent 4 when the balloon 32 is in an expanded state. It can move easily from the position adjacent to the tip side toward the tip side. Thereby, it can avoid that the ring body 54 and the wire 5 inhibit or suppress the expansion of the balloon 32.

FIG. 7 is a plan view illustrating a fourth specific example of the wire of the present embodiment.
FIG. 7A is a plan view showing a state before the stent 4 is expanded. FIG. 7B is a plan view showing a state after the stent 4 is expanded. FIG.7 (c) is a top view showing a state when a balloon catheter is extracted.

  In this specific example, a plurality of second wires 6 are further provided on the proximal end portion of the balloon catheter 3 with respect to the first specific example described above with reference to FIGS. 4 (a) to 4 (c). . In this specific example, the wire 5 of the first specific example described above with reference to FIGS. 4A to 4C corresponds to the first wire 5 of the specific example. One end 61 of the second wire 6 is fixed to a proximal end portion of the balloon catheter 3 disposed on the proximal end side with respect to the stent 4. In the present embodiment, one end portion 61 of the second wire 6 is fixed to the outer surface of the distal end portion of the distal end side outer tube 312a by an adhesive or heat fusion.

  Note that one end 61 of the second wire 6 only needs to be fixed to the proximal end portion of the balloon catheter 3 disposed on the proximal end side with respect to the stent 4, and is attached to the distal end portion of the distal outer tube 312 a. It is not limited to being fixed. For example, one end portion 61 of the second wire 6 may be fixed to the proximal-side joint portion 32 b of the balloon 32 disposed on the proximal side with respect to the stent 4. In the present specification, the “proximal end portion of the balloon catheter 3” refers to a portion of the balloon catheter 3 that is disposed on the proximal end side with respect to the stent 4. The “proximal end portion of the balloon catheter” of the present invention corresponds to, for example, the distal end portion of the distal end side outer tube 312 a or the proximal end side joint portion 32 b of the balloon 32. In the following description, a case where one end portion 61 of the second wire 6 is fixed to the distal end portion of the distal end side outer tube 312a is taken as an example.

  The material for forming the second wire 6 is not particularly limited. As a forming material of the second wire 6, for example, a metal can be used. Examples of the material for forming the second wire 6 include the same metal as the metal of the wire 5 described above with reference to FIG. Alternatively, the material for forming the second wire 6 may be, for example, the biodegradable polymer described above with reference to FIGS.

  The second wire 6 of this specific example reduces a step 46 between the surface portion 321 of the balloon 32 and the proximal end portion 42 of the stent 4. Therefore, when the second wire 6 is pulled out with the stent 4 attached to the balloon 32, the step 46 between the surface portion 321 of the balloon 32 and the proximal end portion 42 of the stent 4 is removed. It can suppress that it gets caught in the edge of a guiding catheter. Therefore, the passage of the stent 4 with respect to the guiding catheter can be improved. Moreover, it can suppress that the stent 4 falls from the balloon 32, and can suppress that the base end part 42 of the stent 4 is turned up. “The proximal end portion 42 of the stent 4 is turned up” means that the stent 4 does not fall off the balloon 32 when the proximal end portion 42 of the stent 4 is hooked on the edge of the guiding catheter, for example. 4 indicates that the outer diameter of the proximal end portion 42 is larger than the outer diameter of the central portion of the stent 4 or the proximal end portion 42 of the stent 4 is folded. Further, when the stent 4 is pulled out while being attached to the balloon 32, the second wire 6 extends in the direction of the axis 49 (see FIG. 2) of the stent 4, and the surface portion 321 of the balloon 32 and the stent 4 The step 46 between the base end portion 42 is reduced. Therefore, the second wire 6 does not cover the entire circumference of the step 46 between the surface portion 321 of the balloon 32 and the proximal end portion 42 of the stent 4. Thereby, it can suppress that the softness | flexibility of the stent 4 with which the balloon 32 was mounted | worn is impaired, and the softness | flexibility of the stent 4 can be maintained.

  The other end 62 of the second wire 6 opposite to the one end 61 of the second wire 6 covers the proximal end 42 of the stent 4 attached to the deflated balloon 32. Specifically, when the stent 4 is withdrawn in a state where it is attached to the balloon 32, the second wire 6 has the other end portion 62 positioned closer to the distal end side than the one end portion 61. The base end 42 of the stent 4 is covered. The other end 62 of the second wire 6 is not fixed to the stent 4 or the balloon 32.

  Thus, the second wire 6 more reliably reduces the step 46 between the surface portion 321 of the balloon 32 and the proximal end portion 42 of the stent 4, and the surface portion 321 of the balloon 32 and the base of the stent 4 are reduced. It can suppress more reliably that the part of the level | step difference 46 between the edge parts 42 is caught in the edge part of a guiding catheter. Therefore, the passage of the stent 4 with respect to the guiding catheter can be further improved. Moreover, it can suppress that the stent 4 falls from the balloon 32, and can suppress that the base end part 42 of the stent 4 is turned up.

  7B, the other end portion 62 of the second wire 6 does not reach the proximal end portion 42 of the expanded stent 4, so that when the balloon 32 is expanded, the stent 4 is expanded. Away from the proximal end 42. Therefore, it can be avoided that the second wire 6 inhibits or suppresses the expansion of the balloon 32.

  Further, as shown in FIG. 7C, since the other end 52 of the wire 5 is not fixed to the stent 4 or the balloon 32, when the balloon catheter 3 is removed, the wire 5 The end 52 extends in the direction of the axis 49 of the stent 4 in a state where the end 52 is located on the distal end side with respect to the one end 51. Thereby, it can suppress that the wire 5 overlaps with the stent 4 indwelled in the target site | part, or is caught, and can suppress that the indwelling position of the stent 4 shifts | deviates. This is as described above with reference to FIG.

  Further, as described above, the other end 62 of the second wire 6 is not fixed to the stent 4 or the balloon 32. Therefore, when the stent 4 is delivered to the target site while being attached to the balloon 32, the second wire 6 has the other end 62 positioned closer to the proximal end than the one end 61. Extends in the direction of the axis 49. That is, the extending direction of the second wire 6 can be reversed between when the balloon catheter 3 is inserted into the living body and when the balloon catheter 3 is removed from the body. As a result, when the stent 4 is delivered to the target site while being attached to the balloon 32, the second wire 6 is prevented from being caught by the stent 4, and the influence on the placement of the stent 4 is suppressed. Can do.

FIG. 8 is a plan view illustrating a fifth specific example of the wire of the present embodiment.
FIG. 8A is a plan view showing a state before the stent 4 is expanded. FIG. 8B is a plan view showing a state after the stent 4 is expanded.

  In this specific example, a plurality of second wires 6 are further provided at the proximal end portion of the balloon catheter 3 with respect to the second specific example described above with reference to FIGS. 5A and 5B. . In this specific example, the wire 5 of the second specific example described above with reference to FIGS. 5A and 5B corresponds to the first wire 5 of the specific example. One end 61 of the second wire 6 is fixed to a proximal end portion of the balloon catheter 3 disposed on the proximal end side with respect to the stent 4. This is as described above with reference to FIGS. 7 (a) to 7 (c). The material for forming the second wire 6 is as described above with reference to FIGS. 7 (a) to 7 (c).

  On the other hand, in this specific example, as shown in FIG. 8A, the other end portion 62 of the second wire 6 covers the proximal end portion 42 of the stent 4 attached to the balloon 32 in the contracted state. The polymer 63 is connected to the proximal end portion 42 of the stent 4. The polymer 63 is preferably a biodegradable polymer. Examples of the biodegradable polymer include the biodegradable polymers described above with reference to FIGS.

  Therefore, the second wire 6 has a more reliable step 46 between the surface portion 321 of the balloon 32 and the proximal end portion 42 of the stent 4 while being connected to the proximal end portion 42 of the stent 4 by the polymer 63. It is possible to more reliably suppress the stepped portion 46 between the surface portion 321 of the balloon 32 and the proximal end portion 42 of the stent 4 from being caught by the edge of the guiding catheter. Therefore, the passage of the stent 4 with respect to the guiding catheter can be further improved, and the stent 4 can be prevented from falling off the balloon 32. Moreover, it can suppress that the base end part 42 of the stent 4 is turned up.

  The connection strength by the polymer 63 is lower than the connection strength by an adhesive or heat fusion. Therefore, as shown in FIG. 8B, the other end portion 62 of the second wire 6 connected by the polymer 63 is released from the polymer 63 when the balloon 32 is in an expanded state. Thereby, it can avoid that the polymer 63 and the 2nd wire 6 inhibit or suppress the expansion of the balloon 32.

FIG. 9 is a plan view illustrating a sixth specific example of the wire of the present embodiment.
FIG. 9A is a plan view showing a state before the stent 4 is expanded. FIG. 9B is a plan view showing a state after the stent 4 is expanded.

  In this specific example, a plurality of second wires 6 are further provided on the proximal end portion of the balloon catheter 3 with respect to the third specific example described above with reference to FIGS. 6A and 6B. . In this specific example, the wire 5 of the third specific example described above with reference to FIGS. 6A and 6B corresponds to the first wire 5 of the specific example. Further, the ring body 54 of the third specific example described above with reference to FIGS. 6A and 6B corresponds to the first ring body 54 of the specific example. One end 61 of the second wire 6 is fixed to a proximal end portion of the balloon catheter 3 disposed on the proximal end side with respect to the stent 4. This is as described above with reference to FIGS. 7 (a) to 7 (c). The material for forming the second wire 6 is as described above with reference to FIGS. 7 (a) to 7 (c).

  On the other hand, in this specific example, as shown in FIG. 9A, the other end 62 of the second wire 6 is connected to the second ring body 64. The second ring body 64 is formed so as to surround the deflated balloon 32, and is provided adjacent to the proximal end side of the stent 4 attached to the deflated balloon 32. The material for forming the second ring body 64 is not particularly limited. Examples of the material for forming the second ring body 64 include metals. Examples of the material for forming the second ring body 64 include the same metal as the metal of the wire 5 described above with reference to FIG. Alternatively, the material for forming the second ring body 64 may be, for example, the biodegradable polymer described above with reference to FIGS. The outer diameter of the second ring body 64 is the same as the outer diameter of the stent 4.

  Therefore, the second ring body 64 to which the other end portion 62 of the second wire 6 is connected more reliably reduces the step 46 between the surface portion 321 of the balloon 32 and the proximal end portion 42 of the stent 4. And it can suppress more reliably that the part of the level | step difference 46 between the surface part 321 of the balloon 32 and the base end part 42 of the stent 4 is caught in the edge part of a guiding catheter. Therefore, the passage of the stent 4 with respect to the guiding catheter can be further improved. Moreover, it can suppress that the stent 4 falls from the balloon 32, and can suppress that the base end part 42 of the stent 4 is turned up.

  As shown in FIG. 9B, the second ring body 64 moves from the position adjacent to the proximal end side of the stent 4 toward the proximal end side when the balloon 32 is in an expanded state. When the space between the expandable portion and the proximal end side joint portion 32b is formed in a tapered shape like the balloon 32 of the present embodiment, the second ring body 64 has the balloon 32 in an expanded state. Then, it can move easily from the position adjacent to the proximal end side of the stent 4 toward the proximal end side. Thereby, it can avoid that the 2nd ring body 64 and the 2nd wire 6 inhibit or suppress expansion of the balloon 32.

  The embodiment of the present invention has been described above. However, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the claims. A part of the configuration of the above embodiment can be omitted, or can be arbitrarily combined so as to be different from the above.

  2 ... Stent delivery system, 3 ... Balloon catheter, 4 ... Stent, 5 ... Wire (first wire), 6 ... Second wire, 31 ... Shaft body, 32 ..Balloon 32a... Distal end side joint portion 32b... Proximal end side joint portion 32c... Expansion space 41... Distal end portion 42. -Step, 49 ... shaft, 51, 52 ... end, 53 ... polymer, 54 ... ring body (first ring body), 61, 62 ... end, 63 ... Polymer, 64 ... second ring body, 311 ... inner tube, 312 ... outer tube, 312a ... distal end side outer tube, 312b ... proximal end side outer tube, 313 ... hub, 313a: guide wire port, 313b: injection 314 ... guide wire lumen, 315 ... lumen for balloon expansion, 316, 317 ... X-ray contrast member, 321 ... surface portion

Claims (8)

A balloon catheter having an expandable and deflated balloon;
A stent attached to the balloon in the deflated state and expanded by the expansion of the balloon;
A plurality of wires each having one end fixed to the tip of the balloon catheter disposed on the tip side of the stent, the step between the surface portion of the balloon and the tip of the stent Wire to reduce,
A stent delivery system comprising:   The other end opposite to the one end covers the distal end of the stent attached to the deflated balloon, and separates from the distal end of the stent when the balloon is in the expanded state. The stent delivery system according to claim 1. The other end is connected to the distal end of the stent by a polymer;
The stent delivery system according to claim 2, wherein the other end connected by the polymer is released from the polymer when the balloon is in the expanded state. The other end opposite to the one end is a ring body provided adjacent to the distal end side of the stent attached to the balloon in the contracted state and has the same outer diameter as the stent Connected to a ring body having an outer diameter,
The stent delivery system according to claim 1, wherein the ring body moves toward a distal end side from a position adjacent to the distal end side of the stent when the balloon is in the expanded state. The wire is a first wire;
A plurality of second wires each having one end fixed to a proximal end portion of the balloon catheter disposed on the proximal end side with respect to the stent, the surface portion of the balloon, and the proximal end portion of the stent The stent delivery system according to any one of claims 1 to 4, further comprising a second wire that reduces a step between the first and second wires.   The other end opposite to one end of the second wire covers the proximal end of the stent attached to the deflated balloon, and when the balloon is in the expanded state, The stent delivery system according to claim 5, wherein the stent delivery system is separated from the proximal end portion. The other end of the second wire is connected to the proximal end of the stent by a polymer;
The stent delivery system according to claim 6, wherein the other end of the second wire connected by the polymer is released from the polymer when the balloon is in the expanded state. The ring body is a first ring body;
The other end opposite to the one end of the second wire is a second ring body provided adjacent to the proximal end side of the stent attached to the balloon in the contracted state. Connected to a second ring body having the same outer diameter as the stent,
The stent delivery system according to claim 5, wherein the second ring body moves toward a proximal end side from a position adjacent to the proximal end side of the stent when the balloon is in the expanded state.

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