JP2012029994A - Stent delivery system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a delivery system wherein detachment of a stent is prevented.SOLUTION: In the stent delivery system, a remote part of an outer shaft is connected to a near part of a balloon 1; an inner shaft composed of a support tube and moreover an inner tube, if necessary, is disposed over a lumen of the outer shaft and the balloon; the balloon is folded in at least two sheets; the stent 8 is diameter-reduced and is disposed on the folded balloon surface; a cross sectional shape perpendicular to a catheter axial direction of the support tube has first wall thickness 11 and second wall thickness 12, and the second wall thickness is formed to be larger than the first wall thickness.

Description

  The present invention relates to a stent delivery system used for inserting a stent into a blood vessel, an esophagus, a trachea, a urethra, a bile duct or the like to expand the inside of the tube and maintain a body cavity.

Stents are widely used to expand a stenosis formed in a body vessel and secure a path. A stent is folded and placed in a catheter called a delivery catheter, inserted into the body, and expanded.
In general, there are two types of delivery catheters. One is a balloon-expandable stent in which a balloon expanded by pressure fluid using a balloon catheter expands the stent by its expansion force. The other is a self-expandable stent having an expandability formed by a shape memory alloy or the like.

  In the case of balloon expandable stents, the stent was folded and clamped to the shaft in order to attach the stent to the delivery catheter. However, in order to hold the stent, the tightening force of the stent from the outside is weak, and the stent is bent at the bent part of a blood vessel such as a blood vessel due to friction with a hemostack valve and a guide catheter during insertion and friction in a meandering vessel. There is a possibility that the stent may be displaced from the initial placement position of the balloon catheter or fall off due to the frictional resistance. If it deviates from the initial arrangement position, the stent does not expand uniformly and the stenosis cannot be expanded sufficiently. In addition, if it falls off, it may remain in the body and is dangerous. The following prior art documents disclose methods for preventing such movement and dropping of the stent.

  In Patent Document 1, it is disclosed that a plurality of protrusions (projections) are provided on the surface of the balloon, thereby preventing the stent from falling off by hooking the stent onto the protrusion or embedding it on the protrusion. Yes.

  However, with this technique, it is difficult to form protrusions on the balloon surface and the inner surface, and there is concern that the protrusions may be caught and embedded in a stent having a complicated shape.

  In Patent Document 2, the movement of the stent is suppressed by hooking the stent by providing a ridge in the circumferential direction of the balloon surface.

  Also by this technique, since a ridge is provided in the circumferential direction of the balloon to form the balloon in a pleat shape, a crimping profile (an outer diameter of the stent after the stent is folded) is increased. Increasing the crimping profile increases the shaft diameter at the catheter tip and decreases flexibility.

  In Patent Document 3, the catheter has a holding sleeve, and the stent is held by covering the end of the stent. In this technique, since the catheter has a sleeve, there is a concern that the profile increases and the number of production steps increases.

  In patent document 4, the movement of a stent is prevented by arrange | positioning a cup and a collar | collar to the both ends of the stent of an inner tube | pipe. However, the cup and collar profiles are large and the flexibility is poor because such a stopper is placed near the tip of the catheter.

  In these prior arts, the balloon is fixed to the stent by catching on the surface of the balloon by a projection or a holding mechanism such as a sleeve or a stopper. When the stent is folded and arranged using such a method, the profile becomes large as compared with a case where a mechanism for preventing the movement of the stent is not included. Since the flexibility becomes worse due to the increase in the profile, there is a problem that the passage resistance becomes large when entering the blood vessel and the trackability performance is deteriorated, the process of attaching the mechanism is complicated, and the man-hour is required. There's a problem.

Special Table 2002-539888 Special Table 2004-527285 Japanese Patent No. 2935561 Japanese Patent No. 4058572

  The problem to be solved by the present invention is to provide a stent delivery system capable of preventing the dropout of the stent and minimizing the deterioration of the trackability.

  As a result of diligent investigations in view of the above problems, the present inventor has found that the distal portion of the outer shaft is connected to the proximal portion of the balloon, and includes a support tube and, if necessary, an inner tube over the lumen of the balloon and the outer shaft. An inner shaft is disposed, the balloon is folded into at least two sheets, a stent is disposed on the folded balloon surface with a reduced diameter, and a cross-sectional shape perpendicular to the catheter axial direction of the support tube Has a first wall thickness and a second wall thickness, and the second wall thickness is formed to be larger than the first wall thickness. According to this, it is possible to prevent the stent from falling off and minimize the deterioration of the trackability.

  In the stent delivery system, the cross-sectional shape perpendicular to the catheter axial direction of the support tube has two or more portions having the second thickness, or separately from the portion having the second thickness. It is preferable to have a portion that is thicker than the first wall thickness and has a third or more wall thickness different from the second wall thickness.

  Further, in the stent delivery system, a balloon that is folded at a portion having two or more second thicknesses of the support tube, or a portion having the second thickness and a portion having a third thickness or more is provided. It is preferable that the stent is press-contacted to a portion to which the folded balloon is pressed and pressed.

  In addition, the stent delivery system is press-contacted via a balloon folded into a portion having the second or more second thickness, or a portion having the second thickness and a portion having the third or more thickness. It is preferable that the outer diameter of the stent is substantially the same as the outer diameter of the stent pressed against the folded balloon disposed radially away from the portion having the first thickness.

  In addition, the stent delivery system is press-contacted via a balloon folded into a portion having the second or more second thickness, or a portion having the second thickness and a portion having the third or more thickness. It is preferable that the outer diameter of the stent further differs from the outer diameter of the stent further pressed against the folded balloon pressed against the portion having the first thickness.

  The stent delivery system may further include a stent strut between adjacent second thickness portions, or between adjacent second thickness portions and third or more thickness portions. It is preferable that they are arranged.

  A distal portion of the outer shaft is connected to the proximal portion of the balloon, and an inner shaft composed of a support tube and, if necessary, an inner tube is disposed over the balloon and the lumen of the outer shaft, Folded into at least two sheets, a stent is disposed on the folded balloon surface with a reduced diameter, and the cross-sectional shape perpendicular to the catheter axial direction of the support tube is the ring-shaped first shape, A stent delivery system having at least two or more second shapes outside the first shape is provided.

  In the stent delivery system, the second shape is preferably a shape obtained by removing a main part from a sector shape.

  In the stent delivery system, the second shape is preferably rectangular.

  In the stent delivery system, the second shape is preferably a triangle.

  Furthermore, in each of the above stent delivery systems, it is preferable that at least a part of the support tube is disposed inside the balloon.

  According to the present invention, the thick portion provided in the support tube supports the stent from the inside to prevent the movement of the stent, and does not use a complicated structure such as a stopper, and the profile is also small, so that the trackability is reduced. And a stent delivery system that can be manufactured by a simpler process.

It is the schematic of a high-speed exchange type balloon catheter. 1 is a schematic view of an over-the-wire type balloon catheter. FIG. It is the schematic of a balloon. It is the schematic of the state which expanded the balloon of the rapid exchange type stent delivery system. It is the schematic of the state which expanded the balloon of the over-the-wire type stent delivery system. The stent delivery system of this invention WHEREIN: The example by which the inner shaft comprised from a support tube was arrange | positioned over the lumen | bore of a balloon and an outer shaft. The stent delivery system of this invention WHEREIN: The example in which the inner shaft comprised from a support tube and an inner tube | pipe was arrange | positioned over the lumen | bore of a balloon and an outer shaft. It is the schematic which expanded a part of cross-sectional shape perpendicular | vertical with respect to the catheter axial direction of a support tube. It is the schematic of the cross section of the radial direction of the support tube which concerns on embodiment. It is the schematic of the cross section of the radial direction of the support tube which concerns on embodiment. It is the schematic of the cross section of the radial direction of the support tube which concerns on embodiment. It is a perspective view of a support tube concerning an embodiment. It is the schematic of a cross section perpendicular | vertical with respect to the catheter axial direction of the stent delivery system which concerns on embodiment. It is the schematic of a cross section perpendicular | vertical with respect to the catheter axial direction of the stent delivery system which concerns on embodiment.

  Embodiments of a stent delivery system according to the present invention will be described below with reference to the drawings.

  Examples of the catheter used in the stent delivery system of the present invention include a high-speed exchange type catheter shown in FIG. 1 and an over-the-wire type catheter shown in FIG. Further, the catheter used in the present invention has a balloon, a support tube, and if necessary, an inner shaft composed of an inner tube, and an outer shaft arranged coaxially on the outer side of the inner shaft. The tip extends from the tip of the outer shaft to the tip side and is connected to the tip of the balloon, and the tip of the outer shaft is connected to the rear end of the balloon. Typically, a guidewire lumen is formed inside the inner shaft, and an inflation lumen is formed outside the inner shaft and inside the outer shaft. In the stent delivery system of the present invention, the stent is arranged with a reduced diameter on the surface of the balloon folded on at least two of the catheters, and particularly in the catheter axial direction of the support tube. The vertical cross-sectional shape has a first thickness and a second thickness, and the second thickness is formed larger than the first thickness, so that the stent holding strength is improved. ing.

  In the following, for each structure of the stent delivery system, an example of a high-speed exchange type of a coaxial type (in addition, a multi-lumen type may be used) in which the outer shaft and the inner shaft are coaxial is exemplified. The stent delivery system will be described.

1. Overall Configuration of Balloon The balloon 1 used in the stent delivery system of the present invention has a cylindrical straight tube portion 1a and conical shapes at both ends as shown in FIG. 3 from the viewpoint of stent expandability and blood vessel insertion. It is preferable to have the following taper 1b. Furthermore, it is preferable to have a cylindrical sleeve 1c at both ends. 4 and 5 show stents placed in the system shown in FIGS. 1 and 2, respectively, and their balloons are expanded (the balloons in FIGS. The tube portion, the taper portion, and the sleeve portion have a columnar shape, a conical shape, and a columnar shape, respectively, but various shapes can be adopted without being limited to this shape. On the other hand, these balloons are folded into at least two sheets, and the stent is arranged with a reduced diameter on the surface thereof, and is in a pre-expansion state used when inserted into a blood vessel.

2. Material of Balloon Various materials can be used as the material of the balloon 1, and a material that can be biaxially stretched is particularly preferable. For example, polyolefins, polyolefin elastomers, polyesters, polyester elastomers, polyamides, polyamide elastomers, polyurethanes, polyurethane elastomers, and the like can be used. Polyester elastomers, polyamides, and polyamide elastomers are preferred.

3. Balloon Production Method For example, a balloon can be produced by blow molding using a tube called a parison and pressurizing in a heated mold. The method for producing the balloon is not limited to this method, and may be a method for producing the balloon by dipping a resin on the outside of the mold. As a method for producing a balloon, there are dipping molding, blow molding and the like, and it is possible to select a suitable method. However, blow molding is preferable in order to realize sufficient pressure resistance necessary for a balloon for stent expansion. . For example, a tubular parison having an arbitrary size is first formed by extrusion molding or the like. A balloon having the same shape as the mold shape can be formed by disposing the tubular parison in a mold having a shape corresponding to the balloon shape and stretching it in the axial direction and the radial direction by a biaxial stretching process. . The axial stretching may be performed simultaneously with or before or after the radial stretching, and may be annealed to stabilize the shape and dimensions of the balloon.

4). Examples of materials for inner tube, support tube, outer tube and hub In the case of a coaxial structure with a coaxial double tube, the material of support tube 10 and inner tube 2 constituting the inner shaft is polyolefin, polyolefin elastomer, polyester Polyester elastomer, polyamide, polyamide elastomer, polyurethane, polyurethane elastomer, etc. can be used. However, since the guide wire lumen is generally defined by the inner surface of the support tube 10 and the inner tube 2, considering the sliding property of the guide wire. Polyethylene, particularly high density polyethylene is preferred. In addition, the support tube 10 and the inner tube 2 may have a multilayer structure, and the innermost layer may be made of high-density polyethylene and the outermost layer may be made of a material that can be bonded or fused to the balloon or the outer tube 3 in order to ensure the sliding property of the guide wire. Is possible. More preferably, substantially the entire area of the support tube 10 and the inner tube may be configured with a single layer structure, and only the connection portion between the balloon 1 and the outer tube 3 may be configured with a multilayer structure. Furthermore, in order to further improve the slidability of the guide wire, it is possible to apply a lubricious coating such as silicon or polytetrafluoroethylene on the inner surface of the inner tube 2.

  The material of the outer tube 3 is not particularly limited as in the case of the support tube 10 and the inner tube 2, and polyolefin, polyolefin elastomer, polyester, polyester elastomer, polyamide, polyamide elastomer, polyurethane, polyurethane elastomer, or the like can be used. In addition, when the outer tube 3 needs further rigidity to improve operability, a metal tube may be connected to the proximal end side. The metal tube may be made of stainless steel or other metal, and may have an antithrombogenic coating on the outside thereof.

  As a material constituting the hub 5 or the manifold 6, polycarbonate, polyamide, polyurethane, polysulfone, polyarylate, styrene-butadiene copolymer, polyolefin, or the like can be preferably used.

5. Manufacturing method of support tube The support tube 10 can be formed by simultaneously forming portions having different thicknesses on the outer side of the inner tube 2 according to the shape of the mold during tube extrusion (particularly, the second tube on the support tube). The type in which the thick part is arranged parallel to the tube axis direction can be created relatively easily, but when creating a non-parallel type, it is necessary to devise a mold or the like). Or you may arrange | position another member using the same material or another material for changing wall thickness on the outer side of the tube extruded in the tubular shape. It is possible to connect the separate members by bonding using an adhesive or by thermal welding by heat melting. It is also possible to create the inner shaft by removing a portion of the outer wall of the tube extruded into a tubular shape. For the removal of the outer wall, a method of cutting with a blade, or by partially melting and removing it by heat melting or a solvent is used.

6). Method of joining balloon, outer tube, inner tube, and support tube The method of joining the balloon 1 to the outer tube 3, the inner tube 2 and the support tube 10 is not particularly limited. For example, bonding with an adhesive, heat fusion, etc. Can be used. Further, the composition and chemical structure of the adhesive used and the curing type are not limited. From the point of composition and chemical structure, adhesives such as urethane type, silicone type, epoxy type and cyanoacrylate type can be used. From the point of curing type, two-component mixed type, UV curable type, water absorption curable type Adhesives such as heat curing type and radiation curing type can be used. However, when an adhesive is used, the rigidity of the joint portion at the joint portion between the sleeve 1c and the outer tube 3 on the rear end side of the balloon 1 and the sleeve 1c and the inner tube 2 or the support tube 10 on the tip end side of the balloon 1 is increased. It is preferable to use an adhesive having a hardness after curing that does not change discontinuously before and after the joint, and is selected in consideration of the rigidity of the balloon 1, the outer tube 3, the inner tube 2, and the support tube 10. It is desirable.

7). Arrangement and structure of inner tube and support tube Examples of the stent delivery system of the present invention (both examples are coaxial type and fast exchange type) are shown in FIGS. 6 (a), 6 (b), 7 (a) and 7 (b). Indicated. FIGS. 6A and 6B are examples in which the inner shaft composed of the support tube 10 is disposed over the lumens of the balloon and the outer shaft. FIG. 6B shows an example in which a three-layer structure is further provided at the connection portion between the balloon 1 and the outer shaft 3 of the support tube 10 and the balloon 1 and the outer shaft 3 are connected by welding. This makes it possible to increase the connection strength while minimizing the decrease in flexibility of the connection portion.

  On the other hand, FIGS. 7A and 7B are examples in which the inner shaft composed of the support tube 10 and the inner tube 2 is disposed across the lumens of the balloon and the outer shaft (in other words, the support in FIG. 6). A part of the tube 10 is replaced with the inner tube 2). In the case where a part of the inner shaft is constituted by the inner tube 3, it is desirable that at least a part of the support tube is arranged inside the balloon in order to prevent the stent from moving and dropping. Further, as shown in FIG. 7B, the inner tube 2 and the support tube 10 may be alternately arranged. On the other hand, in FIG. 7B, similarly to FIG. 6B, a three-layer structure is further provided at the connection portion between the support tube 10 and the balloon 1 and the outer shaft 3, and the balloon 1 and the outer shaft 3 are welded together. This is an example of connection.

  Further, the cross-sectional shape perpendicular to the catheter axial direction of the support tube 10 in the stent delivery system of the present invention has a first wall thickness 11 and a second wall thickness 12, for example, as shown in FIG. The second wall thickness 12 is formed to be larger than the first wall thickness 11 (having portions having different wall thicknesses). Further, the cross-sectional shape perpendicular to the catheter axial direction of the support tube is a third thickness different from the second thickness which is thicker than the first thickness, apart from the portion having the second thickness. You may have the part which has the above thickness (in other words, you may have two or more parts which are thicker than 1st thickness and differ in thickness mutually). Here, the wall thickness can be measured on the screen by cutting the support tube 10 perpendicularly to the catheter axial direction and observing the cross section with a micro digital high scope.

  FIG. 9 shows cross-sectional views (a), (b), and (c) of application examples of the support tube 10. As shown in this figure, it is preferable that the cross-sectional shape perpendicular to the catheter axial direction of the support tube has two or more portions having the second thickness. Alternatively, a portion having the second thickness and a portion having a thickness greater than or equal to the first thickness and a thickness greater than or equal to the third thickness different from the second thickness. It is also preferable to have (in other words, it is also preferable to have two or more portions that are thicker than the first wall and have different wall thicknesses). In addition, since the part which has a thickness larger than these 1st thickness increases the part which contacts a stent, it is preferable. Further, as shown in FIG. 10, the second thickness may exist over a wide range.

  As shown in FIG. 11, the support tube 10 has a ring-shaped first shape 13 perpendicular to the catheter axial direction, and at least two second shapes 14 outside the first shape. It is desirable that In addition, the second shape may be a shape obtained by removing a main part from a sector, a rectangle, a triangle, or the like.

  The shape of the support tube in the long axis direction may be a structure that extends in the same shape in the catheter axis direction as shown in FIG. 12 (a), or is arranged in the catheter axis direction as shown in FIG. 12 (b). (In particular, the phase is changed at the position in the axial direction in FIG. 12B), and the shape and the number of arrangements can be changed. In particular, the rigidity of the balloon portion can be controlled by changing the shape, arrangement, and number in the catheter axial direction.

8). Example of material of hydrophilic coating A hydrophilic coating may be applied to the outer surface of the catheter in order to facilitate insertion into a blood vessel or a guide catheter. It is preferable to apply a hydrophilic coating that exhibits lubricity when in contact with blood on at least a portion of the shaft that contacts the blood of the catheter. The kind of hydrophilic coating does not limit the effect of the present invention, and hydrophilic polymers such as polyethylene glycol, polyacrylamide, and polyvinylpyrrolidone can be suitably used, and the coating method is not limited.

  In the delivery catheter, when a hydrophilic coating is present on the balloon surface, the stent is easily detached. Therefore, the hydrophilic coating is not applied to the balloon surface or only the portion that contacts the balloon is removed. Further, in order to increase the frictional resistance from above, it is possible to provide a layer having a large friction coefficient such as urethane or rubber.

9. Stent The stent used in the stent delivery system of the present invention (for example, a body cavity opening stent) may be a balloon expandable stent, and the material is not particularly limited, but stainless steel such as SUS316L, cobalt chromium alloy, or the like can be used. Further, the design of the stent is not limited at all.

10. Stent diameter reduction The stent diameter reduction is preferably performed by folding the balloon into several sheets (two or more), winding the balloon around the inner tube around the catheter axial direction. As a method of winding, if there are two sheets, a method of winding a folded balloon in the same rotation direction (S wrap) and a method of winding each in the opposite direction (C wrap) can be used. If there are three or more sheets, a method of winding in the same direction is generally used. On the other hand, the position for reducing the diameter of the stent relative to the balloon is preferably arranged on the straight tube of the balloon.

  Further, the folded balloon is press-contacted to the portion having the second thickness of two or more of the support tube, or the portion having the second thickness and the portion having the third thickness or more, and is further folded. In order to prevent the stent from falling off, it is preferable that the interaction between the stent strut and the portion having the second thickness can be used. Further, as shown in FIG. 13A, via a balloon folded into a portion having a second thickness of 2 or more, or a portion having a second thickness and a portion having a third thickness or more. Reduce the diameter of the stent so that the outer diameter of the pressed stent is approximately the same as the outer diameter of the stent pressed against the folded balloon disposed radially away from the portion having the first thickness. It is possible to make it. In this case, after the stent is pressed against the portion having the second thickness, there is no need to further press the stent against the portion having the first thickness, thereby preventing the stent from being detached while simplifying the manufacturing process. be able to. On the other hand, as shown in FIG. 13 (b), via a balloon folded into a portion having a second thickness of 2 or more, or a portion having a second thickness and a portion having a third thickness or more. It is possible to reduce the diameter of the stent so that the outer diameter of the stent press-contacted differs from the outer diameter of the stent further pressed against the folded balloon pressed to the portion having the first thickness. is there. In this case, it is preferable in that the interaction between the stent strut and the portion having the first thickness can be used to prevent the stent from falling off.

  Further, FIG. 14A shows the case where the number of the portions having the second thickness in FIG. 13A is further increased, but it is more preferable from the viewpoint of preventing the stent from falling off. On the other hand, as shown in FIG. 14B, stent struts may be arranged between adjacent portions having the second thickness. In this case, in order to prevent the stent from falling off, the interaction between the stent strut and the portion having the first thickness can be used, and the rotation of the stent in the circumferential direction with respect to the balloon is easily suppressed.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited at all by these Examples.

Example 1
A stent delivery system was prepared according to the procedure described below.

  A tube-like parison was produced by an extrusion method using polyamide elastomer, and then a balloon (straight tube 1a diameter 3 mm, straight tube 1a length 21 mm) was produced by a biaxial stretch blow molding method using this parison.

  Also, the inner tube 2 (inner diameter 0.42 mm, outer diameter 0.58 mm) made of high-density polyethylene, the support tube 10 (the cross-sectional shape perpendicular to the catheter axial direction is 0.42 mm inner diameter as in FIG. 9B). The outer diameter of the portion having the first thickness of 0.58 mm, the outer diameter of the portion having the second thickness of 0.78 mm, the number of the portions having the second thickness on the same circumference: 6), polyamide Outer shaft 3 made of elastomer (inner diameter 0.76mm, outer diameter 0.90mm), outer layer made by extrusion molding is polyamide elastomer, intermediate layer is low density polyethylene, inner layer is a three layer tube consisting of high density polyethylene The inner tube 9 (inner diameter 0.42 mm, outer diameter 0.56 mm) was prepared, and the balloon, the inner tube 2, the support tube 10, and the outer tube were assembled in the arrangement shown in FIG. The support tube 10 was placed under the straight tube 1a of the balloon. On the other hand, the inner pipe 9 for welding was arranged at the joint between the inner shaft and the balloon and the joint between the inner shaft and the outer shaft, and assembled by welding as shown in FIG.

  This assembly consists of a welding inner tube 9, an inner tube 2 and a support tube 10 in which the balloon rear end side sleeve 1c and the outer shaft 3 tip are joined by thermal welding and connected in the axial direction by welding in advance. The inner shaft was arranged in a coaxial double tube in the outer tube, and the distal end portion of the inner shaft and the balloon distal end side sleeve 1c were joined by thermal welding. Moreover, the transition part was produced by passing the rear-end part of an inner shaft through the hole provided in the side surface of the outer shaft, and fixing by heat welding. In joining these, a core material of an arbitrary size coated with a highly lubricious material such as molded polytetrafluoroethylene was appropriately used to secure an inflation lumen or a guide wire lumen. Further, an inflation tube was extended to the rear end portion of the transition portion, and a hub was bonded to the rear end thereof to produce a balloon catheter. A hydrophilic coating was applied to the shaft portion of the balloon catheter.

  While decompressing the balloon catheter, the balloon is folded into a triset shape (a shape in which the balloon is folded into three blades), and in particular, several stent struts are arranged on the balloon straight tube 1a having the second thickness. Similarly, the diameter was reduced at 80 N to produce a stent delivery system.

(Example 2)
A stent delivery system was produced in the same manner as in Example 1 except that the number of the second wall thickness portions on the support tube was set to four and the balloon folding was changed to a tetraset (four pieces). .

(Comparative Example 1)
A stent delivery system was produced in the same manner as in Example 1 except that the inner tube 2 was disposed throughout the balloon 1 and the outer shaft 3.

(Evaluation of trackability performance by simulated blood vessel plate)
The operability of inserting each sample (Example 1 and Comparative Example 1) into a simulated blood vessel was evaluated. For evaluation, a guide catheter (Launcher: 6Fr, JL3.5, manufactured by Medtronic), a hemostack valve, and a guide wire (Neo's Intermediate: manufactured by Asahi Intec Co., Ltd.) are placed in 37 ° C water, and the guide catheter is used as a simulated blood vessel. A system that was inserted into the plate and circulated water inside the guide catheter, hemostack valve, and plate was used. A sample was inserted from the inlet of the hemostack valve, the hand of the sample was chucked to a load meter, and the resistance value when passing through the plate was measured with the load meter.

(Stent drop strength evaluation)
While gripping the rear end portion of the stent of the prepared sample, the rear end portion of the catheter was pulled to the proximal side by a tensile tester, and the strength when the stent moved relative to the catheter was confirmed.

(Evaluation results)
As a result of the evaluation of the trackability performance with the simulated blood vessel plate, Examples 1 and 2 having a support tube showed the same results as Comparative Example 1 having no support tube and using only the inner tube, and the stent delivery of the present invention It has been found that the system has a passage performance comparable to conventional stent delivery systems.

  On the other hand, in terms of the dropout strength of the stent, both Examples 1 and 2 showed a significant difference with respect to Comparative Example 1, and it was confirmed that the stent had a dropout prevention effect.

1. Balloon 1a. Straight pipe 1b. Taper 1c. Sleeve 2. Inner pipe Outer tube 4. Inflation tube 5. Hub 6. Manifold 7. GW entrance 8. 8. Stent Inner pipe for welding 10. Support tube 11. First wall thickness 12. Second wall thickness 13. First shape 14. Second shape

Claims (11)

A distal portion of the outer shaft is connected to the proximal portion of the balloon, and an inner shaft composed of a support tube and optionally an inner tube is disposed over the balloon and the lumen of the outer shaft, and the balloon has at least 2 The stent is folded on the surface of the folded balloon, the stent is arranged with a reduced diameter, and the cross-sectional shape perpendicular to the catheter axial direction of the support tube has a first thickness and a second thickness. A stent delivery system, wherein the second wall thickness is greater than the first wall thickness. The cross-sectional shape perpendicular to the catheter axial direction of the support tube has two or more portions having the second thickness, or apart from the portions having the second thickness, the cross-sectional shape is thicker than the first thickness. 2. The stent delivery system according to claim 1, wherein the stent delivery system has a portion having a thickness that is not less than a third thickness different from the second thickness. The folded balloon is pressed against the portion having the second thickness of two or more of the support tube, or the portion having the second thickness and the portion having the third thickness or more, and further folded. The stent delivery system according to any one of claims 1 and 2, wherein the stent is pressed against a portion where the balloon is pressed. The outer diameter of the stent pressed through a balloon folded into the portion having the second thickness of 2 or more, or the portion having the second thickness and the portion having the thickness of 3 or more, and 4. The stent delivery system according to claim 3, wherein the outer diameters of the stents pressed against the folded balloon disposed radially away from the portion having the first thickness are substantially the same. The outer diameter of the stent pressed through a balloon folded into the portion having the second thickness of 2 or more, or the portion having the second thickness and the portion having the thickness of 3 or more, and The stent delivery system according to claim 3, wherein the outer diameter of the stent further pressed against the folded balloon pressed against the portion having the first thickness is different. A stent strut is disposed between adjacent portions having the second thickness, or between adjacent portions having the second thickness and portions having a thickness equal to or greater than the third thickness. The stent delivery system according to any one of claims 1 to 5. A distal portion of the outer shaft is connected to the proximal portion of the balloon, and an inner shaft composed of a support tube and optionally an inner tube is disposed over the balloon and the lumen of the outer shaft, and the balloon has at least 2 The stent is folded into more than one sheet, and the stent is disposed on the folded balloon surface with a reduced diameter, and the cross-sectional shape perpendicular to the catheter axial direction of the support tube is the ring-shaped first shape and the first shape. A stent delivery system having at least two second shapes on the outside of the shape. The stent delivery system according to claim 7, wherein the second shape is a shape obtained by removing a main part from a sector shape. The stent delivery system according to claim 7, wherein the second shape is rectangular. The stent delivery system according to claim 7, wherein the second shape is a triangle. The stent delivery system according to any one of claims 1 to 10, wherein at least a part of the support tube is disposed inside the balloon.