Manufacturing method of a stent delivery system

Abstract

To provide a manufacturing method of a stent delivery system with a small stent profile, which can achieve high holding force between a stent and a balloon.SOLUTION: A manufacturing method of a stent delivery system includes: a preparation process for preparing a balloon catheter having a balloon and a stent; a surface treatment process for modifying an outer surface of the balloon or an inner surface of the stent; a first crimping process for applying pressure to the balloon, imparting compression force to the stent, shrinking the stent, and crimping it on the outer surface of the balloon; a release process for releasing the pressure application to the balloon and the compression force to the stent; and a second crimping process for imparting compression force to the stent without applying pressure to the balloon, shrinking the stent, and crimping it on the outer surface of the balloon.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a stent delivery system.

Background Art

[0002] As a treatment method for lesions in a biological lumen such as a blood vessel, a treatment method is known in which a treatment instrument such as a catheter is introduced percutaneously into the biological lumen, and a stent, which is an implantable medical instrument, is implanted. Since the stent has a tubular shape and gaps are formed on its surface, the operator can contract or expand the stent in the radial direction. In addition, in order to prevent restenosis in the biological lumen after stent implantation, a drug-eluting stent in which a drug such as an immunosuppressant is coated on the surface of the stent is also known.

[0003] The stent is delivered to a lesion in a biological lumen such as a stenosis or occlusion by a stent delivery system in a contracted state, and then expanded and implanted in the biological lumen. There are two types of stent expansion methods: balloon-expandable type and self-expandable type. Among these, the balloon-expandable type stent is contracted and crimped onto the balloon of the balloon catheter. After delivery to the target lesion, the operator expands the balloon, and the stent is implanted in the biological lumen. The self-expandable type stent is contracted and constrained within the sheath. After delivery to the target lesion, the constraint of the stent by the sheath is released, and the stent is implanted in the biological lumen.

[0004] To deliver a stent to the target lesion, the stent delivery system must be passable. To allow the stent delivery system to pass through narrow lesions or luminal pathways, the diameter of the stent delivery system must be reduced. Typically, the luminal pathway narrows as it approaches the lesion, and the entrance to the lesion is significantly narrower, so reducing the diameter of the tip and leading edge of the stent delivery system is particularly important. Furthermore, to allow the stent delivery system to pass through tortuous lesions or luminal pathways without damaging them, the tip of the stent delivery system must be able to follow the shape of the lesion or luminal pathway; in other words, improved flexibility of the tip of the stent delivery system is required. Improved flexibility is also required at the proximal end of the stent delivery system to allow it to pass along tortuous lesions or luminal pathways. On the other hand, improved transmissibility is also required at the proximal end of the stent delivery system to prevent buckling of the stent delivery system during passage. Therefore, in stent delivery systems, in order to improve passage, it is necessary to reduce the diameter, improve the flexibility of the tip, and improve the appropriate flexibility and transmission ability of the proximal end.

[0005] In balloon-expandable stents, the outer diameter of the stent delivery system is not uniform from the proximal end to the distal end. In particular, the outer diameter of the stent delivery system is larger in the crimped area compared to the surrounding area due to the influence of the balloon and stent thickness. Therefore, in order to reduce the diameter of the stent delivery system, it is important to reduce the outer diameter of the crimped stent (stent profile) during the crimping process (crimping process) in which the stent is crimped onto the balloon catheter.

[0006] Furthermore, in balloon-expandable stent delivery systems, if the retention force between the stent and the balloon is low, the stent may detach from the balloon during delivery. Therefore, it is important to increase the retention force between the stent and the balloon during the crimping process.

[0007] Patent Document 1 discloses a technique in which, in the crimping process, the stent is shrunk and pressed against the balloon, then fluid is supplied to the balloon to pressurize it, and the pressurized balloon is pressed against the stent to improve the holding force between the stent and the balloon.

[0008] Patent Document 2 discloses a technique in which, in the crimping process, a surface modification treatment such as plasma treatment is applied to the outer surface of the balloon and the inner surface of the stent, and then the stent is shrunk and pressed against the balloon to improve the holding force between the stent and the balloon.

[0009] Patent Document 3 discloses a technique in which, during the crimping process, the balloon is pressurized and heated while the stent is deflated and pressed against the balloon, causing the balloon to expand into the gap of the stent, embedding the stent within the outer surface of the balloon and improving the retention force between the stent and the balloon. Subsequently, the pressurization of the balloon is released, and the stent is deflated again and pressed against the balloon, reducing the stent profile and further strengthening the retention force between the stent and the balloon.

[0010] Patent Document 4 discloses a technique for improving the circumferential and axial burst strength of a balloon by using a multilayer balloon structure in which layers with resin orientation in the circumferential direction and layers with resin orientation in the axial direction are stacked. This allows for achieving the generally required burst strength with a thin balloon and reducing the outer diameter of the balloon region of a balloon catheter.

[0011] Patent Document 5 discloses a technique for improving the flexibility and transmissibility of a balloon catheter by changing the hardness of the inner tube that connects to the tip of the balloon in the axial direction. It also discloses that by increasing the hardness of the proximal segment of the inner tube, good transmissibility is achieved, while thinning the proximal segment and reducing the outer diameter improves the passability of the balloon catheter.

[0012] Patent Document 6 discloses a technique in which the tip end of the inner tube is made more flexible than the proximal end, thereby improving passage through eccentric or meandering stenotic areas due to the flexibility of the tip end, and improving the ease of insertion into blood vessels due to the rigidity of the proximal end. It also discloses that the flexible range of the tip end is at least the connection point with the tip of the balloon portion, preferably from the open end to near the longitudinal center of the balloon portion, or from the open end to near the connection point between the proximal end of the balloon portion and the catheter tube.

[0013] Patent Document 7 discloses a technique for reducing the rigidity of the proximal end of an inner tube by using a flexible resin for the outer layer, while the inner layer of the inner tube uses a highly rigid resin with good ethanol resistance. It also discloses a technique for improving the passage of a balloon catheter by making the tip portion of the inner tube more rigid than the proximal end, thereby imparting flexibility to the tip portion of the inner tube.

[0014] Patent Document 8 discloses a balloon catheter having a proximal shaft, an intermediate shaft, and a tip shaft, wherein the intermediate shaft has the highest flexibility. In the overlap portion where the intermediate shaft and the proximal shaft overlap, an unfixed portion extends beyond the fixed portion where the intermediate shaft is fixed to the proximal shaft, thereby suppressing the elongation of the tip shaft when the balloon catheter is pulled axially towards the proximal end. It also discloses that the transmission performance of the balloon catheter is improved by shortening the length of the intermediate shaft excluding the overlap portion. [Prior art documents] [Patent Documents]

[0015] [Patent Document 1] Japanese Patent Publication No. 2013-244155 [Patent Document 2] International release 2016 / 002526 [Patent Document 3] Special Publication 2009-539560 [Patent Document 4] Japanese Patent Publication No. 2016-209062 [Patent Document 5] Japanese Patent Publication No. 2018-078984 [Patent Document 6] Japanese Patent Publication No. 7-265437 [Patent Document 7] Japanese Patent Publication No. 2017-063985 [Patent Document 8] International release 2014 / 141440 [Overview of the project] [Problems that the invention aims to solve]

[0016] The present invention aims to provide a method for manufacturing a stent delivery system that has a small stent profile and high retention force between the stent and the balloon. [Means for solving the problem]

[0017] A method for manufacturing a stent delivery system that achieves the above objective includes a preparation step of preparing a balloon catheter having a balloon that can be pressurized by the supply of fluid and can expand and contract radially, and a stent having a cylindrical shape with a gap and that can expand and contract radially; a surface treatment step after the preparation step of modifying the outer surface of the balloon or the inner surface of the stent to improve the adhesion between the outer surface of the balloon and the inner surface of the stent; and after the surface treatment step, The stent, having an inner diameter larger than the outer diameter of the balloon, is positioned radially outside the balloon in a contracted or partially expanded state. The device is characterized by comprising: a first crimping step of applying a compressive force radially inward on the outer surface of the stent while pressurizing the balloon, thereby shrinking the stent and pressing it onto the outer surface of the balloon; a release step of releasing the pressurization of the balloon and the compressive force on the stent after the first crimping step; and a second crimping step of applying a compressive force radially inward on the outer surface of the stent without pressurizing the balloon after the release step, thereby shrinking the stent and pressing it onto the outer surface of the balloon. [Effects of the Invention]

[0018] In the stent delivery system configured as described above, by pressurizing the balloon in the first crimping step, a state is formed in which the outer surface of the balloon is pressed against the gaps of the stent, and the holding force between the stent and the balloon is improved. Then, since the compressive force acts in the second crimping step without pressurizing the balloon, the stent profile becomes smaller. Further, the holding force between the stent and the balloon is further improved by the surface treatment step.

Brief Description of the Drawings

[0019] [Figure 1] It is an overall view of the stent delivery system according to this embodiment. [Figure 2] It is a cross-sectional view parallel to the axial direction at the position of the balloon and its vicinity of the stent delivery system in which the balloon and the stent according to this embodiment are in a contracted state. [Figure 3] It is a cross-sectional view parallel to the axial direction at the position of the intermediate shaft of the stent delivery system according to this embodiment and its vicinity. [Figure 4] It is a cross-sectional view perpendicular to the axial direction excluding the stent at the position of the balloon of the stent delivery system in which the balloon according to this embodiment is in a contracted state. [Figure 5] It is an enlarged view at the position of the stent and its vicinity of the stent delivery system in which the balloon and the stent according to this embodiment are in a contracted state. [Figure 6] It is a flowchart of the manufacturing method of the stent delivery system according to this embodiment.

Modes for Carrying Out the Invention

[0020] Embodiments of the present invention will be described below with reference to the drawings. Note that the dimensional ratios in the drawings may be exaggerated for illustrative purposes and may differ from actual ratios. Furthermore, the embodiments shown herein are illustrative examples to embody the technical concept of the present invention and do not limit the invention. All other implementable forms, examples, and operational techniques that can be conceived by those skilled in the art without departing from the spirit of the present invention are included within the scope and spirit of the present invention, as well as within the scope of the invention and its equivalents as described in the claims.

[0021] In the drawings attached to this specification, the direction in which the stent delivery system extends is defined as the axial direction, the direction in which the balloon and stent expand and contract on a plane perpendicular to the axial direction is defined as the radial direction, and the direction perpendicular to the radial direction on a plane perpendicular to the axial direction is defined as the circumferential direction. Furthermore, in the axial direction on the drawings, the side of the stent delivery system that is inserted into the living body is defined as the proximal end, and the side that is manipulated by the operator is defined as the proximal end. When simply referred to as the proximal end and the proximal end, these refer to the end faces of the proximal and proximal ends, respectively.

[0022] As shown in Figures 1 to 5, the stent delivery system 10 according to this embodiment includes an inner tube 20, a tip outer tube 30, an intermediate shaft 40, a base outer tube 50, a connector 60, a reinforcing body 70, a balloon 80, and a stent 90.

[0023] The inner tube 20 extends axially from the tip to the middle of the stent delivery system 10. The tip of the inner tube 20 is the tip of the stent delivery system 10. The lumen of the inner tube 20 allows the guide wire to pass through. As shown in Figure 2, a tip contrast marker 23 and a base contrast marker 24 are located at the tip of the inner tube 20. The tip and base of the inner tube 20 are made of different materials. The tip inner tube 21, which is the tip of the inner tube 20, is made of a softer material than the base inner tube 22, which is the base of the inner tube 20.

[0024] The tip outer tube 30 extends axially from the tip side to the intermediate position of the stent delivery system 10. The inner tube 20 is positioned in the lumen of the tip outer tube 30. The tip of the tip outer tube 30 is closer to the proximal end than the tip of the inner tube 20, and the proximal end of the tip outer tube 30 is closer to the tip than the proximal end of the inner tube 20.

[0025] The intermediate shaft 40 extends axially at an intermediate position in the stent delivery system 10. The tip of the intermediate shaft 40 is connected to the base end of the tip outer tube 30, and the base end of the intermediate shaft 40 is located on the base side of the base end of the inner tube 20. Also, as shown in Figure 3, there is an opening 41 in the wall surface of the intermediate shaft 40, and the base inner tube 22 passes through the opening 41, with no gap between the opening 41 and the outer circumference of the base inner tube 22. The lumen between the intermediate shaft 40 and the base inner tube 22 is in communication with the lumen between the tip outer tube 30 and the base inner tube 22.

[0026] The base outer tube 50 extends axially from the intermediate position to the proximal end of the stent delivery system 10. The tip of the base outer tube 50 is connected to the proximal end of the intermediate shaft 40. The lumens of the base outer tube 50 communicate with the lumens of the intermediate shaft 40 and the lumens between the intermediate shaft 40 and the inner tube 20.

[0027] The connector 60 extends axially on the proximal end side of the stent delivery system 10. The tip of the connector 60 is connected to the proximal end of the base outer tube 50, and the proximal end of the connector 60 is the proximal end of the stent delivery system 10. The lumen of the connector 60 communicates with the lumen of the base outer tube 50. The proximal end of the connector 60 is open, allowing fluid to be supplied into the lumen and fluid to be drawn out from the lumen. The proximal end of the connector 60 can be connected to a device capable of supplying or drawing in fluid, such as a syringe or an indeflerator.

[0028] The reinforcing member 70 extends axially within the lumens of the intermediate shaft 40 and the base outer tube 50. As shown in Figure 3, the tip of the reinforcing member 70 is located beyond the tip of the opening 41, and the base end of the reinforcing member 70 is connected to the base outer tube 50 beyond the tip of the base outer tube 50. The reinforcing member 70 is a solid member.

[0029] The balloon 80 extends axially at the tip end of the stent delivery system 10. The tip of the balloon 80 is connected to the inner tube 20, and the base end of the balloon 80 is connected to the tip outer tube 30. The internal space of the balloon 80 communicates with the lumen between the tip outer tube 30 and the inner tube 20, and the balloon 80 is pressurized or depressurized, expanding or contracting, when fluid is supplied or sucked in. As shown in Figure 4, the contracted balloon 80 has a structure in which convex portions 81, smooth portions 82, and concave portions 83 are alternately arranged along the direction of extension of the balloon 80 on a cross section perpendicular to the axial direction. The smooth portions 82 are in a shape that wraps around the inner tube 20, and the convex portions 81 are convex in the circumferential direction. The expanded balloon 80 is smooth along the circumferential direction, and the cross section of the balloon 80 is circular on a cross section perpendicular to the axial direction.

[0030] As shown in Figure 5, the stent 90 has a cylindrical shape with gaps, formed by multiple wavy annular bodies 93 arranged axially, each having alternating linear and curved sections 91 and 92 sections, with adjacent annular bodies 93 connected by link sections 94 from the tip to the base. In the contracted state, the angle between the linear section 91 adjacent to the curved section 92 (opening of the curved section 92) is small, and the stent 90 is in contact with the balloon 80. When the balloon 80 is expanded, the opening of the curved section 92 increases, causing the stent 90 to expand.

[0031] The manufacturing method of the stent delivery system 10 according to this embodiment consists of a preparation step S10 and a crimping step S20, as shown in Figure 6.

[0032] Preparation step S10 consists of a balloon catheter preparation step S11 for preparing the balloon catheter and a stent manufacturing step S12 for preparing the stent 90.

[0033] In balloon catheter manufacturing process S11, the following components are prepared: inner tube 20, tip outer tube 30, intermediate shaft 40, base outer tube 50, connector 60, reinforcing body 70, and balloon 80. Next, the inner tube 20 is inserted into the tip outer tube 30, and the tip of the balloon 80 is connected to the inner tube 20, and the base end of the balloon 80 is connected to the tip outer tube 30. Next, the base end of the inner tube 20 is passed through the opening 41, and the base end of the tip outer tube 30 is connected to the tip of the intermediate shaft 40. Next, the base end of the reinforcing body 70 is connected to the base outer tube 50, and the base end of the intermediate shaft 40 is connected to the tip of the base outer tube 50. Next, the base end of the base outer tube 50 is connected to the tip of the connector 60.

[0034] In the stent manufacturing process S12, a cylindrical member to be used as material is prepared, and a laser is irradiated onto the contour of the portion that will become the gap in the stent 90 to separate the portion that will become the gap in the stent 90 from the cylindrical member. Next, the separated portion that will become the gap is removed from the cylindrical member to form the shape of the stent 90. Subsequently, the surface of the stent 90 is polished in the polishing process.

[0035] In the crimping process S20, the stent 90 prepared in the stent manufacturing process S12 is crimped onto the balloon catheter prepared in the balloon catheter manufacturing process S11. The crimping process S20 consists of a surface treatment process S21, a first crimping process S22, a release process S23, a second crimping process S24, and a compression release process S25.

[0036] In the surface treatment step S21, plasma treatment is performed on the outer surface of the balloon 80. Plasma treatment is performed by placing the balloon catheter into the chamber of a plasma generator having a chamber, and irradiating the balloon catheter with plasma. For specific details on how to perform plasma treatment, please refer to, for example, Patent Document 2.

[0037] In the first crimping step S22, a stent 90 having a larger inner diameter than the balloon 80 in its reduced diameter state is placed radially outside the balloon 80. A compressive force (external force) is applied to the stent 90 from the radial outside toward the inside, causing the stent 90 to crimp to the balloon 80. The external force is applied by an external force application mechanism, such as that described in Patent Document 1. The external force application mechanism contacts the outer surface of the stent 90 and moves radially toward the inside, causing the stent 90 to reduce in diameter. Subsequently, the inner surface of the stent 90 contacts the outer surface of the balloon 80, and the external force application mechanism moves radially toward the inside, causing the stent 90 to crimp to the balloon 80. The movement of the external force application mechanism stops at an arbitrary position and is held at that position for a certain period of time. While the stent 90 is crimped to the balloon 80, fluid is supplied to the balloon 80 to pressurize it.

[0038] In the release step S23, the external force applied in the first compression step S22 is released, and the balloon 80 is depressurized and deflated. As the external force application mechanism moves radially outward, the external force application mechanism separates from the stent 90, and the external force applied to the stent 90 is released. This state of release from external force is maintained for a certain period of time. Additionally, the balloon 80 is depressurized and deflated by suction of the fluid supplied to the balloon 80.

[0039] In the second crimping step S24, a compressive force (external force) is again applied to the stent 90, which is crimped onto the balloon 80, from the radial outside toward the inside. The method of applying the external force is the same as in the first crimping step S22. The balloon 80 is not pressurized while the stent 90 is being crimped onto the balloon 80.

[0040] In the compression release step S25, the external force applied in the second crimping step S24 is released. As the external force application mechanism moves radially outward, the external force application mechanism separates from the stent 90, and the external force applied to the stent 90 is released. At this point, the crimping step S20 is completed.

[0041] The following details the steps that constitute the manufacturing method of the stent delivery system 10 according to this embodiment.

[0042] In the balloon catheter manufacturing process S11, known balloon catheter manufacturing methods may be applied. The order in which the components constituting the balloon catheter are connected can be changed as appropriate. Alternatively, for example, an intermediate component in which the inner tube 20, the tip outer tube 30, and the balloon 80 are connected may be prepared, a crimping process S20 may be performed on the intermediate component, and then the components other than the intermediate component may be connected to the intermediate component to manufacture the stent delivery system 10.

[0043] In the balloon catheter manufacturing process S11, a deflated balloon 80 is prepared. The deflated balloon 80 has a structure in which convex portions 81, smooth portions 82, and concave portions 83 are alternately arranged along the direction of extension of the balloon 80 on a cross section perpendicular to the axial direction. The smooth portions 82 are shaped to wrap around the inner tube 20, and the convex portions 81 are convex in the circumferential direction.

[0044] In the balloon catheter manufacturing process S11, a balloon 80 that is partially expanded from a deflated state may be prepared. This makes it easier to form a state in the first compression process S22 where the outer surface of the balloon 80 is pressed against the gap of the stent 90, compared to when a deflated balloon 80 is prepared, and improves the holding force between the stent 90 and the balloon 80. The pressure applied to the balloon 80 when partially expanding a deflated balloon 80 is about 5 to 30% of the pressure required until the cross-section perpendicular to the axial direction becomes approximately circular. A restricting member may be placed around the balloon 80 to prevent the balloon 80 from expanding beyond the inner surface of the restricting member. By using a restricting member, the partially expanded state of the balloon 80 can be stably formed. The restricting member is not particularly limited, but for example, it may be a cylindrical resin sheath. When a restricting member is used, the pressure applied to the balloon 80 when partially expanding a deflated balloon 80 may be greater than when a restricting member is not used. For example, that pressure is about 5 to 300% of the pressure required until the cross-section perpendicular to the axial direction becomes approximately circular. If the balloon 80 is not pressurized in the subsequent first crimping step S22, the stent profile after the first crimping step S22 may be smaller if the balloon 80 prepared in the balloon catheter manufacturing step S11 is in a deflated state than if it is in a partially expanded state. On the other hand, if the balloon 80 is pressurized in the first crimping step S22, the stent profile after the first crimping step S22 is the same whether the balloon 80 prepared in the balloon catheter manufacturing step S11 is in a deflated state or a partially expanded state. As long as the balloon 80 is pressurized in the first crimping step S22, it is desirable that the balloon 80 prepared in the stent balloon catheter manufacturing step S11 be in a partially expanded state from a deflated state in order to improve the retention force between the stent 90 and the balloon 80. Furthermore, it is desirable to use a restricting member when partially expanding the balloon 80.

[0045] In the stent manufacturing process S12, a known method for manufacturing a stent 90 may be applied.

[0046] In the surface treatment step S21, the outer surface of the balloon 80 is subjected to all or at least one of the following effects: (a) imparting polar groups such as carboxyl groups, hydroxyl groups, and amino groups to the surface; (b) removing fine organic contaminants adhering to the surface; and (c) imparting roughness to the surface. This improves the retention force between the stent 90 and the balloon 80 after the stent 90 is crimped. Surface treatment methods include plasma irradiation, ultraviolet irradiation, and corona discharge. Of these, plasma treatment is preferred because it allows for easy surface treatment.

[0047] Furthermore, in the surface treatment step S21, when plasma treatment is performed, it is preferable that the balloon 80 of the balloon catheter placed in the chamber of the plasma generator has a smooth portion 82 wrapped around the inner tube 20 and a convex portion 81 that is convex in the circumferential direction. This ensures that the surface of the balloon 80 into which the stent 90 is crimped is reliably surface treated. However, surface treatment may also be performed on the balloon 80 in the expanded state, the balloon 80 in the contracted state where the smooth portion 82 is not wrapped around the inner tube 20, and the balloon 80 that is partially expanded between the expanded and contracted states.

[0048] Furthermore, in the surface treatment step S21, the stent 90 may be subjected to surface treatment. If the stent 90 is made of metal, the surface of the stent 90 will experience all or at least one of the following effects: (d) activation of water molecules hydrated in the oxide film or removal of bound water, and (e) cleaning of fine organic contaminants adhering to the surface, further improving the retention force between the stent 90 and the balloon 80 after the stent 90 has been crimped. Surface treatment may also be applied to the stent 90 if it is coated entirely or partially with a chemical or polymer. In addition, for a partially coated stent 90, surface treatment may be applied to the surface after removing the coated area by masking or the like. As for surface treatment methods for the stent 90, plasma irradiation, ultraviolet irradiation, corona discharge, etc., are applied, similar to the surface treatment methods for the balloon 80. Of these, plasma treatment is preferred because it can be easily performed.

[0049] In the first crimping step S22, the stent 90 is crimped onto the balloon 80, which is in a reduced diameter state. While the stent 90 is being crimped onto the balloon 80, fluid is supplied to the balloon 80 and the balloon 80 is pressurized. When the balloon 80 is pressurized, the holding force between the stent 90 and the balloon 80 is improved compared to when the balloon 80 is not pressurized.

[0050] In the first crimping step S22, the pressure applied to the balloon 80 is not particularly limited, but is, for example, about 5 to 300% of the pressure required to make the cross-section perpendicular to the axial direction approximately circular.

[0051] In the first crimping step S22, the timing for starting pressurization on the balloon 80 may be immediately after positioning the stent 90 radially outside the balloon 80, immediately before the external force applied to the stent 90 is released in the release step S23, or at a timing in between. Preferably, the timing for starting pressurization on the balloon 80 is before the timing when the stent 90 and the balloon 80 come into contact while the external force is being applied. This makes it easier for the outer surface of the balloon 80 to fit into the gap of the stent 90, thus improving the retaining force between the stent 90 and the balloon 80. If the radial distance between the balloon 80 and the stent 90 is large when the stent 90 is positioned radially outside the balloon 80, the amount of expansion of the balloon 80 increases and the stent profile becomes larger. From the viewpoint of achieving both improved retaining force between the stent 90 and the balloon 80 and suppression of the increase in the stent profile, it is desirable to start pressurization on the balloon 80 when the outer diameter of the stent 80 is about 1.1 to 2.0 times the outer diameter of the balloon 80 at the time the stent 90 was positioned. The pressure applied to balloon 80 may or may not be constant from the start to the end of pressurization. There may also be periods during which pressurization is stopped.

[0052] Furthermore, in the first crimping step S22, the application of external force may be stopped while increasing the amount of diameter reduction of the stent 90. While the application of external force is stopped, the contact between the stent 90 and the external force application mechanism may be released to adjust the position of the stent 90. The number of times the external force is stopped is not particularly limited. The rate of diameter reduction of the stent 90 or the rate of increase of the external force may be constant or not. After the amount of diameter reduction of the stent 90 or the external force reaches its maximum, the diameter reduction value or external force may be held for a certain period of time, or the application of external force may be stopped immediately. The time for holding the external force is not particularly limited.

[0053] Furthermore, in the first crimping step S22, the balloon 80 and its surroundings may be heated. Heating the balloon 80 increases its flexibility, making it easier for the outer surface of the balloon 80 to be pressed into the gap in the stent 90, thereby improving the holding force between the stent 90 and the balloon 80. When heating, the temperature should be set lower than the melting point of the balloon 80. If the stent 90 is coated with a polymer or chemical, the heating temperature should be set lower than the lowest temperature among the melting point of the balloon 80, the melting point of the coating polymer, and the temperature at which the chemical becomes inactive. The heating method is not limited. Heating may be done from the outside of the regulating member or from the inside of the balloon 80.

[0054] Furthermore, in the first crimping process S22, it is desirable to insert a core metal into the lumen of the inner tube 20. By inserting a core metal, deformation of the inner tube 20 can be prevented.

[0055] In the release step S23, the external force applied to the stent 90 in the first crimping step S22 is released, and contact between the stent 90 and the external force application mechanism is released. Furthermore, the balloon 80 is depressurized, and the pressure applied to the balloon 80 is released. The rate of decrease of the external force and the rate of depressurization of the balloon 80 are not particularly limited. Also, the time until proceeding to the second crimping step S24 is not particularly limited.

[0056] In the second crimping step S24, the stent 90 is crimped onto the balloon 80, which is in a reduced diameter state. The balloon 80 is not pressurized while the stent 90 is being crimped onto the balloon 80. By not pressurizing the balloon 80, the stent profile can be made smaller compared to when the balloon 80 is pressurized. Also, since the balloon 80 is pressurized in the first crimping step S22, the stent profile after the second crimping step S24 is smaller compared to after the release step S23.

[0057] In the second crimping step S24, the application of external force may be stopped while increasing the amount of diameter reduction of the stent 90. If the external force is stopped, there is no particular limit to the number of times it is stopped. The rate of diameter reduction of the stent 90 or the rate of increase of the external force may be constant or not. After the amount of diameter reduction of the stent 90 or the external force reaches its maximum, the diameter reduction value or the external force may be held for a certain period of time, or the application of external force may be stopped immediately. There is no particular limit to the magnitude of the external force or the time for which the external force is held.

[0058] Furthermore, in the second crimping process S24, it is desirable to insert a core metal into the lumen of the inner tube 20. By inserting a core metal, deformation of the inner tube 20 can be prevented.

[0059] In the compression release step S25, the external force applied to the stent 90 in the second compression step S24 is released, and contact between the stent 90 and the external force application mechanism is released. The rate at which the external force decreases is not particularly limited.

[0060] The following provides further details about each component that makes up the stent delivery system 10 according to this embodiment.

[0061] The inner diameter of the base inner tube 22 is not particularly limited as long as it is a diameter that allows the guide wire to pass through, but is for example 0.1 to 2.0 mm, preferably 0.2 to 0.8 mm. The outer diameter of the base inner tube 22 is not particularly limited, but is for example 0.2 to 2.5 mm, preferably 0.4 to 1.0 mm. The wall thickness of the base inner tube 22 is not particularly limited, but is for example 0.01 to 0.3 mm, preferably 0.03 to 0.15 mm. The length of the base inner tube 22 is not particularly limited, but is for example 100 to 1000 mm, preferably 200 to 600 mm. The inner or outer diameter of the base inner tube 22 may be constant or tapered along the axial direction. The base inner tube 22 may undergo secondary processing such as drawing down. The smaller the outer diameter of the base inner tube 22, the smaller the stent profile and the better the passage of the stent delivery system 10.

[0062] The inner diameter of the tip inner tube 21 is not particularly limited, but it is desirable that it be about the same as the inner diameter of the base inner tube 22 so as not to reduce the passability of the guide wire within the lumen of the inner tube 20. The outer diameter of the tip inner tube 21 is not particularly limited, but it is desirable that it be about the same as the outer diameter of the base inner tube 22. The wall thickness of the tip inner tube 21 is not particularly limited, but it is desirable that it be about the same as the wall thickness of the base inner tube 22. The length of the tip inner tube 21 is not particularly limited, but is, for example, 1 to 80 mm, and preferably 2 to 50 mm. The outer diameter of the tip inner tube 21 may be constant or tapered along the axial direction, but it is desirable that it be tapered. The outer diameter of the base end of the tip inner tube 21 may be constant and the outer diameter of the tip end may be tapered. The smaller the outer diameter of the tip inner tube 21, the smaller the stent profile and the better the passability of the stent delivery system 10. It is desirable that the tip of the tip inner tube 21 be rounded. The base end of the tip inner tube 21 and the tip of the base inner tube 22 may be connected by known techniques such as bonding or fusion. Alternatively, the tip inner tube 21 and the base inner tube 22 may be manufactured integrally by methods such as reducing the hardness of the tip end by heat treatment, chemical treatment, mechanical polishing, etc., after the base inner tube 22 has been manufactured.

[0063] The base inner tube 22 can be made of a known material, such as polyethylene, polyamide, polyimide, or polyolefin. The tip inner tube 21 can be made of a known material, such as a thermoplastic elastomer such as polyurethane, polyester, polyamide, olefin, or styrene. The base inner tube 22 and tip inner tube 21 may contain a pigment. The hardness of the tip inner tube 21 is not particularly limited, but it is desirable that it be lower than the hardness of the base end. By making the hardness of the tip inner tube 21 lower than that of the base inner tube 22, the flexibility of the tip of the stent delivery system 10 is improved, and the passability of the stent delivery system 10 is improved compared to the case where the hardness of the tip inner tube 21 is equal to or greater than that of the base inner tube 22. The axial position of the base end of the tip inner tube 21 is not particularly limited, but it is desirable to be near the tip of the balloon 80, near the base end of the balloon 80, or somewhere in between.

[0064] The base inner tube 22 may have a multilayer structure with different hardnesses along the radial direction. A base inner tube 22 in which the hardness of the radial outer layer is lower than the hardness of the radial inner layer, or vice versa, offers improved flexibility compared to a single-layer base inner tube 22 made of a high-hardness material, thereby improving the passage of the stent delivery system 10. The number of layers is not particularly limited, but for example, it can be 2 to 3 layers. In the case of 3 or more layers, the hardness of the intermediate layer may be the highest. The material of each layer is not particularly limited, but for example, the materials of the base inner tube 22 and tip inner tube 21 described above can be used. The tip inner tube 21 may also have a multilayer structure with different hardnesses.

[0065] The shape of the tip contrast marker 23 and the base contrast marker 24 is not particularly limited, but a cylindrical shape is preferable. The inner diameter of the tip contrast marker 23 and the base contrast marker 24 is approximately the same as the outer diameter of the base inner tube 22. The wall thickness is not particularly limited, but is, for example, 0.01 to 0.2 mm. The axial length of the tip contrast marker 23 and the base contrast marker 24 is not particularly limited, but is, for example, 0.1 to 10 mm. The material of the tip contrast marker 23 and the base contrast marker 24 can be a known radiopaque material such as gold, platinum, tantalum, or iridium. To suppress the reduction in flexibility of the base inner tube 22, it is preferable to have a small wall thickness and a short length, as long as it is visible during fluoroscopy. The axial position of the tip contrast marker 23 and the base contrast marker 24 is not particularly limited, but is preferably near the tip and proximal end of the stent 90, for example. The tip and base of the tip contrast marker 23 may be located either tip-side or proximal-side to the tip of the stent 90, or the tip of the tip contrast marker 23 may be located tip-side to the tip of the stent 90 and the base of the tip contrast marker 23 may be located proximal-side to the tip of the stent 90. Similarly, the tip and base of the base contrast marker 24 may be located either proximal-side or tip-side to the base of the stent 90, or the base of the base contrast marker 24 may be located proximal-side to the base of the stent 90 and the tip of the base contrast marker 24 may be located tip-side to the proximal-side to the base of the stent 90. Only one of the tip contrast marker 23 or the base contrast marker 24 may be used. The tip contrast marker 23 and the base contrast marker 24 and the base inner tube 22 may be connected by known techniques such as crimping, bonding, or fusion. The tip contrast marker 23 and the base contrast marker 24 may be pressed into the inner tube 20 such that the outer surface of the inner tube 20 is recessed. The tip contrast marker 23 or the base contrast marker 24 may be connected to the tip inner tube 21.

[0066] The inner diameter of the tip outer tube 30 is not particularly limited as long as it is a diameter that allows the inner tube 20 to pass through, but for example it is 0.5 to 2.5 mm, preferably 0.6 to 2.0 mm. The outer diameter of the tip outer tube 30 is not particularly limited, but for example it is 0.7 to 3.0 mm, preferably 0.9 to 1.6 mm. The wall thickness of the tip outer tube 30 is not particularly limited, but for example it is 0.01 to 0.3 mm, preferably 0.03 to 0.15 mm. The length of the tip outer tube 30 is not particularly limited, but for example it is 100 to 1000 mm, preferably 200 to 600 mm. The inner or outer diameter of the tip outer tube 30 may be constant or tapered along the axial direction. The tip outer tube 30 may undergo secondary processing such as drawing down. The smaller the outer diameter of the tip outer tube 30, the better the passage of the stent delivery system 10.

[0067] The material of the tip outer tube 30 can be a known material, such as polyethylene, polyamide, polyimide, polyolefin, or thermoplastic elastomers such as polyurethane, polyester, polyamide, olefin, or styrene. The material of the tip outer tube 30 can be the same as that of the inner tube 20. It may also contain a pigment.

[0068] The tip outer tube 30 may have a multilayer structure with different hardnesses along the radial direction. A tip outer tube 30 in which the hardness of the radial outer layer is lower than the hardness of the radial inner layer, or vice versa, offers improved flexibility compared to a single-layer tip outer tube 30 made of a high-hardness material, thereby improving the passage of the stent delivery system 10. The number of layers is not particularly limited, but for example, it can be 2 to 3 layers. In the case of 3 or more layers, the hardness of the intermediate layer may be the highest. The material of each layer is not particularly limited, but the material of the tip outer tube 30 described above can be applied.

[0069] The inner diameter of the intermediate shaft 40 is not particularly limited as long as it is large enough to allow the base inner tube 22 to pass through from the tip to the opening 41, but is for example 0.5 to 2.5 mm, preferably 0.6 to 2.0 mm. The outer diameter of the intermediate shaft 40 is not particularly limited, but is for example 0.7 to 3.0 mm, preferably 0.9 to 1.6 mm. The wall thickness of the intermediate shaft 40 is not particularly limited, but is for example 0.01 to 0.3 mm, preferably 0.03 to 0.15 mm. The length of the intermediate shaft 40 is not particularly limited, but is for example 10 to 200 mm, preferably 20 to 100 mm. The direction in which the axis of the intermediate shaft 40 extends is approximately parallel to the axial direction of the stent delivery system 10, but may be inclined from the axial direction of the stent delivery system 10 at and near the location of the opening 41.

[0070] The position of the opening 41 of the intermediate shaft 40 is not particularly limited, but for example, it is located within a range of 2 to 30 mm from the tip of the intermediate shaft 40. The direction of extension of the axis of the base inner tube 22 at the position of the opening 41 may be parallel to the axial direction of the stent delivery system 10, parallel to the radial direction of the stent delivery system 10, or in an inclined direction corresponding to one of these two directions. The base end of the base inner tube 22 may be outside the intermediate shaft 40 beyond the opening 41, or it may be at the same position as the opening 41 or partially overlapping it.

[0071] The tip of the intermediate shaft 40 and the base end of the tip outer tube 30 are connected by known techniques such as bonding or fusion. The end faces may be connected to each other, or the tip outer tube 30 may be inserted into the lumen of the intermediate shaft 40 for connection, or the intermediate shaft 40 may be inserted into the lumen of the tip outer tube 30 for connection. When connecting the tip outer tube 30 or the intermediate shaft 40 by inserting them into the lumen of the intermediate shaft 40 or the tip outer tube 30, the entire overlapping section in the axial direction may be connected, or only a portion of it may be connected. The connection is made such that there is no fluid leakage from the connection point.

[0072] The intermediate shaft 40 can be made of known materials, such as polyethylene, polyamide, polyimide, polyolefin, or thermoplastic elastomers such as polyurethane, polyester, polyamide, olefin, or styrene. The intermediate shaft 40 can be made of the same material as the inner tube 20 or the tip outer tube 30. It may also contain a pigment.

[0073] The region of the intermediate shaft 40 from the opening 41 to the proximal end has reduced rigidity because the inner tube 20 is absent. Although a reinforcing body 70 may be present within the lumen, if the material of the intermediate shaft 40 is soft, the rigidity will still decrease. In this case, the region from the opening 41 to the tip will also have reduced rigidity. If the rigidity of the region of the intermediate shaft 40 is relatively low within the stent delivery system 10, the transmission efficiency during delivery will decrease, so it is preferable for the length of the intermediate shaft 40 to be shorter.

[0074] The inner diameter of the base outer tube 50 is not particularly limited as long as it is a diameter that allows the reinforcing body 70 to pass through, but is for example 0.5 to 2.5 mm, preferably 0.6 to 2.0 mm. The outer diameter of the base outer tube 50 is not particularly limited, but is for example 0.7 to 3.0 mm, preferably 0.9 to 1.6 mm. The wall thickness of the base outer tube 50 is not particularly limited, but is for example 0.01 to 0.3 mm, preferably 0.03 to 0.15 mm. The length of the base outer tube 50 is not particularly limited, but is for example 100 to 2000 mm, preferably 500 to 1500 mm. The inner or outer diameter of the base outer tube 50 may be constant or tapered along the axial direction. The base outer tube 50 may undergo secondary processing such as drawing down. The smaller the outer diameter of the base outer tube 50, the better the passage of the stent delivery system 10.

[0075] The base outer tube 50 can be made of a known material, such as stainless steel or titanium alloy. The same material as the inner tube 20 and the tip outer tube 30 may also be used.

[0076] The tip of the base outer tube 50 and the base end of the intermediate shaft 40 are connected by known techniques such as bonding or fusion. The end faces may be connected to each other, the base outer tube 50 may be inserted through the lumen of the intermediate shaft 40 for connection, or the intermediate shaft 40 may be inserted through the lumen of the base outer tube 50 for connection. When connecting by inserting the base outer tube 50 or the intermediate shaft 40 through the lumen of the intermediate shaft 40 or the base outer tube 50, the entire overlapping section in the axial direction may be connected, or only a portion of it may be connected. The connection is made such that there is no fluid leakage from the connection point.

[0077] Depth markers may be provided on the outer surface of the base outer tube 50 to visually indicate the approximate insertion length of the stent delivery system 10 into the body during delivery. The depth markers may be a separate component from the base outer tube 50, or they may be provided by surface treatment of the outer surface of the base outer tube 50.

[0078] The connector 60 can have any known shape, for example, a cylindrical shape with a flat projection on its outer surface. The inner diameter of the connector 60 is not particularly limited, but is, for example, 0.5 to 2.5 mm, preferably 0.6 to 2.0 mm. The length of the connector 60 is not particularly limited, but is, for example, 10 to 50 mm. The material of the connector 60 can be any known material, for example, a resin material such as polycarbonate or acrylic.

[0079] The outer diameter of the reinforcing body 70 is not particularly limited as long as it can be inserted into the lumen of the base outer tube 50, but is, for example, 0.05 to 1.5 mm, preferably 0.1 to 0.5 mm. The length of the reinforcing body 70 is not particularly limited, but is, for example, 50 to 1500 mm. The base end of the reinforcing body 70 is connected to the base outer tube 50 on the base end side of the tip of the base outer tube 50. The outer surface of the reinforcing body 70 and the inner surface of the base outer tube 50 are connected by known techniques such as bonding or fusion. The connection is made on the base end side, the tip side, or in between of the base outer tube 50. There may be one or more connection points. The tip of the reinforcing body 70 is preferably located on the tip side of the opening 41, and is located within the range of the intermediate shaft 40 or the tip outer tube 30. By having the tip of the reinforcing body 70 on the tip side of the opening 41, the rigidity of the region from the base end of the intermediate shaft 40, which has low rigidity, to the opening 41 is improved, and the transmission performance of the stent delivery system 10 is improved. The tip of the reinforcing body 70 is not connected to the intermediate shaft 40 or the tip outer tube 30, but it may be connected. The diameter of the reinforcing body 70 may be constant along the axial direction, or it may be tapered. The entire reinforcing body 70 may be tapered, or only a part of the reinforcing body 70 may be tapered. If the reinforcing body 70 is tapered, the inclination of the tapered region may or may not be constant. There may be multiple tapered regions. The inclination and its rate of change may differ from region to region. The reinforcing body 70 is preferably a solid member, but it may also be a hollow member.

[0080] The outer diameter of the balloon 80 is not particularly limited, but when expanded at the recommended expansion pressure, it is, for example, 1 to 10 mm, preferably 1.5 to 4.0 mm. The length of the balloon 80 is not particularly limited, but for example, 3 to 100 mm, preferably 5 to 60 mm. The wall thickness of the balloon 80 is not particularly limited, but for example, 0.01 to 0.2 mm, preferably 0.02 to 0.05 mm. In the expanded state, the tip and base ends of the balloon 80 taper toward the end in the axial direction. The angle of this taper is not particularly limited. Between the tapered region at the tip and the tapered region at the base, the outer diameter is approximately constant in a straight line. In the deflated state, the balloon 80 has a structure in which convex portions 81, smooth portions 82, and concave portions 83 are alternately arranged along the extending direction of the balloon 80 on a cross section perpendicular to the axial direction. The smooth portions 82 are shaped to wrap around the inner tube 20, and the convex portions 81 are convex in the circumferential direction. The number of protrusions 81 is not particularly limited, but is for example 2 to 8, preferably 3 to 6. The base end of the balloon 80 and the tip end of the tip outer tube 30 are connected by known techniques such as bonding or fusion. The connection range within the base end region of the balloon 80 and the tip region of the tip outer tube 30 is not particularly limited, but they are connected in such a way that there is no fluid leakage from the connection. The tip end of the balloon 80 and the tip end of the base inner tube 22 or the tip inner tube 21 are connected in the same way.

[0081] The material of balloon 80 can be a known material, such as polyethylene, polyamide, polyimide, polyolefin, or thermoplastic elastomers such as polyurethane, polyester, polyamide, olefin, and styrene. Balloon 80 is designed not to rupture below a specified pressure. With materials that have low breaking strength, rupture of balloon 80 below the specified pressure can be prevented by increasing the wall thickness. With materials that have high breaking strength, rupture of balloon 80 below the specified pressure can be prevented even if the wall thickness is designed to be thinner than with materials that have low breaking strength. Therefore, by using a material with high breaking strength as the material for balloon 80, the wall thickness can be designed to be thinner, the stent profile can be made smaller, and the passability of the stent delivery system 10 is improved.

[0082] The balloon 80 may have a multilayer structure along the radial direction. Different materials with different hardnesses may be applied to each layer. The orientation direction of the resin may differ from layer to layer. If the orientation direction of the resin differs, the same type of material may be applied to each layer. Generally, when the resin is oriented, the tensile strength along the orientation direction improves, so when the orientation direction differs from layer to layer, the tensile strength along the orientation direction of each layer improves. When the orientation direction of each layer is the same, the tensile strength in directions other than the orientation direction is lower than when the orientation direction differs from layer to layer, making the balloon 80 more prone to rupture. Therefore, a multilayer balloon 80 with different orientation directions for each layer can be designed with a thinner wall thickness than a multilayer balloon 80 with the same material and the same orientation direction for each layer, and rupture below the specified pressure can be prevented, thus allowing for a smaller stent profile. In addition, a multilayer balloon 80 with different orientation directions for each layer may be less prone to rupture than a single-layer balloon 80 composed of a material with a higher hardness than at least some of the layers. Therefore, a multilayer balloon 80 with different orientation directions for each layer is desirable. For example, stretch blow molding is known as a method for manufacturing the balloon 80. In this case, by adjusting the axial stretch ratio, circumferential stretch ratio, material, and the timing of molding each layer, a multilayer balloon 80 with different orientation directions for each layer can be manufactured.

[0083] The number of layers in the multilayer balloon 80 is not particularly limited, but for example, it may be 2 to 3 layers. The hardness may increase from the inner layer to the outer layer, or from the outer layer to the inner layer. The layer between the inner and outer layers may have the highest hardness.

[0084] The stent 90 is expandable by the expansion of the balloon 80 and is not particularly limited as long as it has a cylindrical shape with gaps; any stent 90 having known shapes, dimensions, and material combinations can be applied. The shape of the stent 90 is, for example, a cylindrical shape with gaps formed by arranging multiple wavy annular bodies 93, each having alternating linear portions 91 and curved portions 92, in the axial direction, with adjacent annular bodies 93 connected by link portions 94 from the tip to the base. The dimensions of the stent 90 are, for example, an inner diameter of 0.5 to 2.0 mm in the contracted state, an inner diameter of 1.5 to 10 mm in the expanded state, a wall thickness of 0.05 to 0.2 mm, and an axial length of 5 to 100 mm. The material of the stent 90 is, for example, a metal such as stainless steel or CoCr alloy, or a polymer such as polylactic acid.

[0085] Based on the above, the contents of the present invention are described again below.

[0086] [1] A method for manufacturing a stent delivery system, comprising: a preparation step of preparing a balloon catheter having a balloon that can be pressurized by the supply of a fluid and is expandable and contractible in the radial direction, and a stent having a cylindrical shape with a gap and being expandable and contractible in the radial direction; a surface treatment step after the preparation step of modifying the outer surface of the balloon or the inner surface of the stent to improve the adhesion between the outer surface of the balloon and the inner surface of the stent; a first crimping step after the first surface treatment step of pressurizing the balloon and applying a compressive force radially inward on the outer surface of the stent to contract the stent and crimp it onto the outer surface of the balloon; a release step after the first crimping step of releasing the pressurization of the balloon and the compressive force on the stent; and a second crimping step after the release step of not pressurizing the balloon and applying a compressive force radially inward on the outer surface of the stent to contract the stent and crimp it onto the outer surface of the balloon.

[0087] [2] The method for manufacturing a stent delivery system according to [1] above, characterized in that the outer surface of the balloon or the inner surface of the stent is modified by plasma irradiation in the surface treatment step.

[0088] [3] The method for manufacturing the stent delivery system according to [1] or [2] above, characterized in that the balloon has a structure in which the resin is divided into multiple layers along the radial direction, and the orientation direction of the resin is different for each layer.

[0089] [4] The method for manufacturing the stent delivery system according to [1] to [3] above, wherein the balloon catheter has an outer tube that extends axially and has a tip and a proximal end, and an inner tube that extends axially within the outer tube and has a tip that is on the tip side of the outer tube and a proximal end that is on the proximal side of the outer tube, the tip of the balloon is connected to the tip side of the inner tube, the proximal end of the balloon is connected to the tip side of the outer tube, the inner tube has a tip inner tube that is on the tip side and a base inner tube that is on the proximal side, and the hardness of the tip inner tube is lower than the hardness of the base inner tube.

[0090] [5] The method for manufacturing the stent delivery system according to [4] above, characterized in that the base inner tube is divided into an inner layer and an outer layer along the radial direction, and the hardness of the outer layer is lower than the hardness of the inner layer.

[0091] Due to the features described in [1] above, pressurizing the balloon in the first crimping step creates a state where the outer surface of the balloon is pressed against the gap in the stent, improving the retention force between the stent and the balloon. Furthermore, since a compressive force is applied in the second crimping step without pressurizing the balloon, the stent profile becomes smaller. In addition, the surface treatment step further improves the retention force between the stent and the balloon.

[0092] Having the features described in [2] above, the surface treatment process can be easily carried out.

[0093] As a result of having the characteristics described in [3] above, the fracture strength along the orientation direction of each layer is improved, making it possible to make the balloon thinner and reduce the stent profile.

[0094] The characteristics described in [4] above improve the flexibility of the tip of the stent delivery system and improve the passability of the stent delivery system.

[0095] The features described in [5] above improve the flexibility of the base tube and enhance the passage of the stent delivery system.

[0096] Although the manufacturing method of the stent delivery system according to the present invention has been described above, the present invention is not limited to the configurations described herein, and can be appropriately modified by those skilled in the art within the technical concept of the present invention, and such modifications should be considered to fall within the technical scope of the present invention. [Explanation of Symbols]

[0097] 10 Stent Delivery System 20 inner tube 21. Inner tube at the tip 22 Base inner canal 23. Advanced contrast markers 24 Base contrast markers 30 Tip outer tube 40 Intermediate shaft 41 Opening 50 Basal outer tube 60 connectors 70 Reinforcement 80 balloons 81 Convex part 82 Smooth section 83 recess 90 stents 91 Linear part 92 Curved section 93 Ring-shaped body 94 Link section

Claims

1. A method for manufacturing a stent delivery system, comprising: a preparation step of preparing a balloon catheter having a balloon that can be pressurized by the supply of fluid and is radially expandable and contractible, and a stent having a cylindrical shape with a gap and being radially expandable and contractible; a surface treatment step after the preparation step of modifying the outer surface of the balloon or the inner surface of the stent to improve the adhesion between the outer surface of the balloon and the inner surface of the stent; and after the surface treatment step of preparing a stent having an inner diameter larger than the outer diameter of the balloon on the radially outside of the balloon in a contracted or partially expanded state. A method for manufacturing a stent delivery system, comprising: a first crimping step of positioning the stent in a certain state, applying a compressive force radially inward on the outer surface of the stent while pressurizing the balloon, thereby contracting the stent and pressing it onto the outer surface of the balloon; a release step of releasing the pressurization of the balloon and the compressive force on the stent after the first crimping step; and a second crimping step of applying a compressive force radially inward on the outer surface of the stent without pressurizing the balloon after the release step, thereby contracting the stent and pressing it onto the outer surface of the balloon.

2. The method for manufacturing a stent delivery system according to claim 1, characterized in that, in the surface treatment step, the outer surface of the balloon or the inner surface of the stent is modified by plasma irradiation.

3. The method for manufacturing a stent delivery system according to claim 1, characterized in that the balloon has a structure in which the resin is divided into multiple layers along the radial direction, and the orientation direction of the resin is different for each layer.

4. The method for manufacturing a stent delivery system according to claim 1, wherein the balloon catheter has an outer tube that extends axially and has a tip and a proximal end, and an inner tube that extends axially within the outer tube and has a tip that is closer to the tip of the outer tube and a proximal end that is closer to the proximal end of the outer tube, the tip of the balloon is connected to the tip side of the inner tube, the proximal end of the balloon is connected to the tip side of the outer tube, the inner tube has a tip inner tube that is on the tip side and a base inner tube that is on the proximal end side, and the hardness of the tip inner tube is lower than the hardness of the base inner tube.

5. The method for manufacturing a stent delivery system according to claim 4, characterized in that the base inner tube is divided into an inner layer and an outer layer along the radial direction, and the hardness of the outer layer is lower than the hardness of the inner layer.

6. The method for manufacturing a stent delivery system according to claim 1, further comprising the step of placing a restricting member around the contracted balloon and pressurizing the balloon to partially expand it before the first compression step.

Images