Crimping method, method for manufacturing balloon catheter, biological indwelling object, and crimping device

Abstract

[Problem] To provide a crimping method, a method for manufacturing a balloon catheter, a biological indwelling object, and a crimping device with which it is possible to reduce the rate of occurrence of pinholes while improving the crimping power and reducing the profile. [Solution] A crimping method for crimping an expandable cylindrical stent 10 to a balloon 220 using one or more pressing members 410 configured to be capable of moving radially inward, the crimping method including disposing the stent on the outer-circumferential side of the balloon, pressing the heated pressing member from the outer-surface side of a porous structure 20 to thereby reduce the diameter of the stent, and pressurizing the interior of the balloon at least once.

Description

Crimping method, balloon catheter manufacturing method, indwelling device, and crimping device

[0001] The present invention relates to a crimping method, a method for manufacturing a balloon catheter, an indwelling device, and a crimping device.

[0002] Stents are known as medical devices used to treat lesions caused by stenosis or occlusion in biological lumens such as blood vessels. There are various types of stents, including a so-called "balloon-expandable stent (balloon-expandable stent delivery system)" that is delivered to the lesion while crimped onto the balloon of a balloon catheter, and then deployed at the lesion by expanding the balloon.

[0003] In the manufacturing method of the above-described balloon-expandable stent delivery system (hereinafter also simply referred to as "stent delivery system"), a crimping step is carried out in which the stent is crimped (held) on the outer peripheral surface of the balloon.

[0004] The crimping process is performed using a crimping device such as that described in Patent Document 1. The crimping device of Patent Document 1 includes multiple pressing members (crimp heads) configured to move toward and away from a balloon and a stent disposed on the outer circumferential surface of the balloon. In the crimping process performed using the crimping device of Patent Document 1, the balloon and stent are positioned near the center of the pressing members' approach direction, and each of the multiple pressing members approaches the stent radially inward from the outer circumferential side, applying a pressing force to press the stent against the balloon, thereby crimping the stent against the outer circumferential surface of the balloon. In addition, in the crimping process using the crimping device of Patent Document 1, while the multiple pressing members are pressing against the outer circumferential side of the stent as described above, the inside of the balloon is pressurized, thereby sandwiching the balloon into the gaps between the struts of the stent, thereby further improving the crimping force of the stent against the balloon and reducing the profile after crimping.

[0005] JP 2016-101520 A

[0006] One possible way to reduce the stent profile is to increase the pressing force of the pressing member during crimping (the crimp load of the crimp head). For example, conventionally, a method of crimping while pressurizing a balloon, such as the crimping process described in Patent Document 1, has often been adopted. However, with this method, if the pressing force of the pressing member increases, the force with which the stent clamps the balloon becomes excessively strong, increasing the likelihood of pinholes occurring in the balloon. On the other hand, a method of crimping without pressurizing the balloon can reduce the incidence of pinholes, but it is difficult to increase the crimp force and reduce the profile.

[0007] The present invention has been made in view of the above-mentioned problems, and aims to provide a crimping method, a manufacturing method of a balloon catheter, an indwelling device, and a crimping device that can improve the crimping force and reduce the profile while reducing the incidence of pinholes.

[0008] The above object of the present invention can be achieved by any of the following means (1) to (14).

[0009] (1) A crimping method for crimping an expandable cylindrical stent onto a balloon using at least one pressing member configured to be movable radially inward, the method comprising: placing the stent on the outer periphery of the balloon; compressing the stent by applying heated pressing members to the outer surface of the porous structure covering the outer periphery of the stent; and pressurizing the inside of the balloon at least once.

[0010] (2) The crimping method described in (1) above, wherein a drug coating layer is disposed on the surface of the stent facing the porous structure, and recesses and protrusions corresponding to the porous structure are formed in the drug coating layer by pressing the pressing member against the porous structure.

[0011] (3) The crimping method according to (1) or (2), wherein the pressing member is heated to a temperature higher than 25°C and lower than 55°C, and the pressing member presses the porous structure from the outer surface side.

[0012] (4) The crimping method according to any one of (1) to (3) above, wherein at least a portion of the porous structure is pre-fixed to the stent before the stent is placed on the outer circumferential side of the balloon.

[0013] (5) A crimping method according to (4) above, in which a sheet-like member is placed between the porous structure and the pressing member, and the heated pressing member is pressed from the outer surface side of the sheet-like member and the outer surface side of the porous structure.

[0014] (6) The crimping method according to any one of (1) to (3) above, wherein the porous structure is arranged to cover the outer periphery of the stent with the stent arranged on the outer periphery of the balloon.

[0015] (7) The crimping method according to (6) above, wherein the porous structure is formed of a sheet-like member, and the pressing member presses the porous structure from the outer surface side while the stent is sandwiched between a plurality of the sheet-like porous structures.

[0016] (8) The crimping method according to (6) above, wherein the porous structure is formed of a tubular member having an inner cavity, and the pressing member presses the porous structure from the outer surface side with the stent inserted into the inner cavity of the porous structure.

[0017] (9) A method for manufacturing a balloon catheter, which uses the crimping method according to any one of (1) to (8) above.

[0018] (10) A living body implant placed on the outer periphery of an expandable and contractible balloon, comprising: an expandable cylindrical stent crimped on the outer periphery of the balloon; and a porous structure placed so as to cover the stent, at least a portion of which is fixed to the stent, wherein the stent has a drug coating layer placed on the surface of the stent facing the porous structure, the porous structure having a void portion penetrating through the thickness of the porous structure and a skeletal portion partitioning the void portion, and the drug coating layer having concave and convex portions corresponding to the void portion and the skeletal portion.

[0019] (11) The indwelling device according to (10) above, wherein at least a part of the porous structure is disposed in a state of being embedded in the recess of the drug coating layer.

[0020] (12) The indwelling device according to (10) or (11) above, wherein the porous structure is made of a metal or a polymer.

[0021] (13) The stent has linear rings that form the outer periphery of a cylindrical shape with gaps formed therein, and a plurality of link portions that connect the rings to each other at the gaps, the drug coating layer is not formed on the link portions, and the porous structure is fixed to at least the link portions, in a living body indwelling device described in any one of (10) to (12) above.

[0022] (14) A crimping device for crimping an expandable cylindrical stent onto a balloon, comprising: at least one pressing member that reduces the diameter of the stent as it moves radially inward, thereby crimping the stent onto the balloon located on the inner periphery of the stent; and a supply unit that supplies at least one porous structure between the pressing member and the stent.

[0023] (15) The crimping device according to (14) above, further comprising a heating section for heating the pressing member.

[0024] According to the crimping method described in (1), it is possible to improve the crimping force of the indwelling device and reduce the profile of the indwelling device, while reducing the incidence of pinholes.

[0025] 1 is a schematic plan view showing a stent delivery system including a living body implant according to an embodiment. FIG. 1 is a schematic plan view showing a stent and a porous structure according to an embodiment in a reduced diameter state. FIG. 2 is a schematic plan view showing a stent and a porous structure according to an embodiment in an expanded diameter state. FIG. 3 is a partially enlarged view showing a portion of the stent and a porous structure in an expanded diameter state. FIG. 4 is a partially enlarged view showing a portion of the stent and a porous structure in a reduced diameter state. FIG. 5 is a cross-sectional view of the stent and a porous structure taken along arrows 7A-7A in FIG. 6, which is an enlarged view of the dashed line portion 6A in FIG. 5. FIG. 6 is a schematic view showing a portion of a drug coating layer provided on a stent. FIG. 7 is an orthogonal cross-sectional view taken along arrows 9A-9A in FIG. 1 (an orthogonal cross-sectional view of the living body implant in a reduced diameter state). FIG. 8 is a perspective view showing a crimping device according to an embodiment. FIG. 9 is a flowchart of a crimping method according to an embodiment. FIG. 10 is a view for explaining the crimping method according to an embodiment, showing a state in which preparations prior to constructing a living body implant are set in the crimping device. FIG. 11 is a view for explaining the crimping method according to an embodiment. FIG. 12 is a view for explaining the crimping method according to an embodiment.

[0026] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Note that the following description does not limit the technical scope or meaning of terms described in the claims. Also, the dimensional proportions in the drawings are exaggerated for the convenience of explanation and may differ from the actual proportions.

[0027] The embodiment will be described with reference to FIGS.

[0028] FIG. 1 is a diagram showing a stent delivery system 300 including a living body implant 100 according to an embodiment. FIGS. 2 to 9 are diagrams illustrating the living body implant 100, stent 10, and porous structure 20 according to an embodiment. FIG. 2 is a schematic plan view showing the stent 10 and porous structure 20 according to an embodiment in a contracted state. FIG. 3 is a schematic plan view showing the stent 10 and porous structure 20 according to an embodiment in an expanded state. FIG. 4 is an enlarged view of a portion of the stent 10 and porous structure 20 shown in FIG. 3. FIG. 5 is a further enlarged view of a portion of the stent 10 and porous structure 20 according to an embodiment. FIG. 6 is an enlarged view of the dashed line portion 6A shown in FIG. 5. FIG. 7 is a cross-sectional view of the stent 10 and porous structure 20 taken along arrows 7A-7A in FIG. 6. FIG. 8 is a schematic view showing a portion of a drug coating layer 18 provided on a stent 10 according to an embodiment. FIG. 9 is an orthogonal cross-sectional view taken along the arrow 9A-9A in FIG. 1 (an orthogonal cross-sectional view of the living body indwelling device 100 in a reduced diameter state).

[0029] Fig. 10 is a diagram showing a crimping device 400 according to the embodiment. Fig. 11 is a flowchart showing the steps of the crimping method according to the embodiment, and Figs. 12 to 15 are diagrams for explaining the crimping method according to the embodiment.

[0030] In this specification, the longitudinal direction in which the stent 10 extends is referred to as the "axial direction," the direction perpendicular to the axial direction (the direction of approaching or moving away from the central axis O of the indwelling device 100 and the catheter main body 210 in the orthogonal cross section shown in FIG. 9 ) is referred to as the "radial direction," and the rotational direction based on the central axis O (the clockwise and counterclockwise directions in the orthogonal cross section shown in FIG. 9 ) is referred to as the "circumferential direction (outer or inner circumferential direction)." Furthermore, the side of the stent 10 that is inserted into a living body is referred to as the "distal side," and the side opposite the distal side, where the surgeon operates the stent delivery system 300, is referred to as the "proximal side."

[0031] <Body indwelling device 100> As shown in Fig. 1, the body indwelling device 100 according to this embodiment is disposed on the outer periphery of an expandable and contractable balloon 220. As shown in Figs. 2 and 9, the body indwelling device 100 has an expandable cylindrical stent 10 crimped onto the outer periphery of the balloon 220, and a porous structure 20 disposed so as to cover the stent 10 and at least a portion of which is fixed to the stent 10.

[0032] 6 and 7, the stent 10 has a drug coating layer 18 disposed on the surface of the stent 10 facing the porous structure 20 (the outer surface 10b facing the outside of the stent 10). However, the drug coating layer 18 is not provided on the inner surface 10a facing the inside of the stent 10.

[0033] 6 shows a plan view of a portion of the drug coating layer 18 formed on the outer surface 10b of the stent 10. For convenience of illustration, the drug coating layer 18 is omitted in the drawings in this specification except for FIGS. 6, 7, and 8.

[0034] The stent 10 and the porous structure 20 constitute the indwelling device 100 together with the balloon 220 when they are arranged on the outer circumferential surface of the balloon 220 of the balloon catheter 200 (when the stent 10 is crimped onto the balloon 220).

[0035] The balloon catheter 200 equipped with the indwelling device 100 constitutes a stent delivery system 300. The stent delivery system 300 delivers the indwelling device 100 in a contracted state to the lesion, and expands the diameters of the stent 10 and the porous structure 20 as the balloon 220 expands, thereby placing the stent 10 and the porous structure 20 at the lesion.

[0036] The balloon catheter 200 has a long catheter body 210 , a balloon 220 provided at the tip of the catheter body 210 , and a hub 230 fixed to the base end of the catheter body 210 .

[0037] The balloon catheter 200 is configured as a rapid exchange type balloon catheter that allows a guide wire W to be introduced from near the distal end of the catheter main body 210 and passed through the distal end side of the balloon 220. The balloon catheter 200 can also be configured as a so-called over-the-wire type balloon catheter.

[0038] For example, an organic polymer material can be used as the material for the balloon 220. Specifically, polymer materials such as polyolefin (e.g., polyethylene, polypropylene, polybutene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ionomer, or a mixture of two or more of these), polyvinyl chloride, polyamide, polyamide elastomer, polyurethane, polyurethane elastomer, polyimide, fluororesin, or a mixture of these, or an elastic resin material such as two or more of the above polymer materials can be used, and among these, polyamide-based resins can be preferably used as the main material.

[0039] The living body indwelling device 100 will now be described in detail.

[0040] The indwelling device 100 according to this embodiment is used to treat strictures or obstructions that occur in blood vessels, bile ducts, tracheas, esophagus, urethra, or other biological lumens. The stent 10 used in the indwelling device 100 is configured as a so-called balloon-expandable medical device, which is placed in a crimped state on a folded balloon 220, and is expanded and placed at the lesion after being delivered to the lesion.

[0041] 2 to 4, the stent 10 has a cylindrical shape extending in the axial direction. The porous structure 20 is disposed so as to cover the outer periphery of the stent 10, and has the same cylindrical shape as the stent 10.

[0042] As shown in FIGS. 2, 3, 4 and 5, the stent 10 has a distal end 10A, a proximal end 10B, and a fixing portion 30 for fixing the porous structure 20 to the stent 10.

[0043] The stent 10 is configured to be capable of radial expansion (the state shown in FIGS. 3 and 4) and contraction (the state shown in FIG. 2).

[0044] As shown in Figures 3 to 6, the stent 10 has linear rings 11 that form the outer periphery of a cylindrical shape with gaps formed therein, and link portions 12 that connect the rings 11 with gaps defined between adjacent linear rings 11 in the axial direction.

[0045] The rings 11 extend circumferentially of the stent 10 in a wave-like pattern that moves back and forth in the axial direction. As shown in Figure 4, the wave-like rings 11 have a plurality of straight or curved first strut portions 15, straight or curved second strut portions 16, and curved portions 17 formed between the first strut portions 15 and the second strut portions 16. Furthermore, as shown in Figure 4, the rings 11 have a plurality of straight or curved third strut portions 14 that are adjacent to one side of the link portion 12 in the axial direction and that form a pair in the circumferential direction.

[0046] The rings 11 are arranged in a row along the axial direction, and adjacent rings 11 in the axial direction are integrated by links 12. Therefore, by increasing or decreasing the number of rings 11, it is possible to easily obtain a stent 10 of a desired length.

[0047] 6 and 7, a drug coating layer 18 may be provided on at least a portion of the outer surface 10b of the stent 10. For example, the drug coating layer 18 may be disposed on the first strut portion 15 and the third strut portion 14 of the ring 11 shown in FIG.

[0048] In this embodiment, the drug coating layer 18 is not provided on the link portions 12. The portions of a predetermined range including the link portions 12 where the drug coating layer 18 is not provided constitute exposed portions 19. Specifically, the curved portions 17 of the ring 11 and the link portions 12 (areas where stress concentrates and / or distortion occurs due to expansion and deformation) are configured as exposed portions 19. Because the drug coating layer 18 is not formed on the curved portions 17 and the link portions 12 of the ring 11, peeling or falling off of the drug coating layer 18 due to bending or distortion caused by stress concentration on the drug coating layer 18 when the stent 10 is expanded in diameter can be prevented.

[0049] The drug coated on the outer surface 10b of the stent 10 is carried by a polymer to form the drug coating layer 18. The polymer is preferably a biodegradable polymer. In this case, after the stent 10 is placed in a living body, the drug is gradually released while the polymer is biodegraded, thereby more reliably preventing restenosis at the stent placement site in the living body and suppressing inflammation caused by the polymer.

[0050] The biodegradable polymer is, for example, at least one polymer selected from the group consisting of polyester, aliphatic polyester, polyanhydride, polyorthoester, polycarbonate, polyphosphazene, polyphosphate ester, polyvinyl alcohol, polypeptide, polysaccharide, protein, and cellulose, a copolymer obtained by arbitrarily copolymerizing the monomers constituting the polymer, and a mixture of the polymers and / or the copolymers. Examples of the aliphatic polyester include polylactic acid (PLA), polyglycolic acid (PGA), and lactic acid-glycolic acid copolymer (PLGA).

[0051] A primer coating layer (not shown) may be disposed between the drug coating layer 18 and the outer surface 10b of the stent 10. Any primer may be selected to form the primer coating layer, taking into consideration its adhesiveness to the polymer contained in the drug coating layer 18 and its adhesiveness to the outer surface 10b of the stent 10. By providing a primer coating layer, the peel resistance of the drug coating layer 18 can be improved.

[0052] The stent 10 can be made of a metallic material or a polymer material. When the stent 10 is made of a metallic material, the material used is not particularly limited, and any metallic material commonly used for known stents can be used. Specific examples include stainless steels such as SUS304, SUS316, SUS316L, SUS420J2, and SUS630; tantalum; titanium; nickel-titanium alloys; tantalum-titanium alloys; nickel-aluminum alloys; Inconel; gold; platinum; iridium; tungsten; and cobalt-based alloys such as cobalt-chromium (Co—Cr) alloys.

[0053] Furthermore, when the stent 10 is made of a polymer material, the material to be used is not particularly limited, and any polymer material generally used for known stents can be used. Specific examples include polyolefins such as polyethylene and polypropylene, aromatic polyesters such as polyethylene terephthalate, cellulose-based polymers such as cellulose acetate and cellulose nitrate, and fluorine-containing polymers such as polytetrafluoroethylene and tetrafluoroethylene-ethylene copolymers.

[0054] The porous structure 20 is disposed so as to cover the outer periphery of the stent 10 and is capable of expanding in diameter in accordance with the expansion of the diameter of the stent 10 .

[0055] As shown in FIGS. 5 and 6, the porous structure 20 has voids 24a that penetrate the porous structure 20 in the thickness direction, and a skeleton 24b that defines the voids 24a.

[0056] The indwelling device 100 has the porous structure 20 disposed on the outer periphery of the stent 10, and therefore when the stent 10 is expanded in a blood vessel, the porous structure 20 can be biased against the blood vessel in accordance with the expansion of the stent 10. Therefore, the indwelling device 100 can prevent the porous structure 20 from coming off or shifting from the indwelling site due to the pressure of the blood flowing in the blood vessel.

[0057] The porous structure 20 has a cylindrical shape extending in the axial direction, and has a mesh structure consisting of voids 24a and a skeleton 24b.

[0058] 4, 5, and 6, the gaps in the mesh structure of the porous structure 20 are configured to be smaller than the gaps between adjacent rings 11 of the stent 10. This configuration makes it possible to prevent peripheral embolism from occurring when the stent 10 is expanded in diameter to place it in the lesion.

[0059] The size of each of the multiple voids 24a in the porous structure 20 is preferably smaller than the area of ​​the gaps between the rings 11 of the stent 10. By adopting such a configuration, it is possible to prevent plaque and thrombus from scattering as the stent 10 expands. On the other hand, the size of the voids 24a is preferably larger than the area of ​​a single blood cell contained in blood. This allows blood cells to pass through the voids 24a. Furthermore, since the voids 24a impart extensibility to the porous structure 20, when the stent 10 expands in diameter, the porous structure 20 also elongates in the circumferential direction as the stent 10 expands in diameter, thereby exhibiting good follow-up ability (expandability) to the expansion of the stent 10.

[0060] The porous structure 20 can be made of, for example, a knitted fabric, a woven fabric (braid), or a molded product (a member such as a membrane with slits formed therein). When the porous structure 20 is a knitted fabric, the porous structure 20 can be made of a stockinette stitch. By making the porous structure 20 of a stockinette stitch, it is possible to prevent the axial length of the porous structure 20 from shortening as the stent 10 expands. When the porous structure 20 is a woven fabric, the woven fabric is made of a known weaving method. Alternatively, the porous structure 20 may be made of a molded product obtained by drilling holes in a tubular body formed by injection molding or the like. The size, shape, and number of the stitches and weaves of the porous structure 20 are not particularly limited as long as they are capable of preventing peripheral embolism during the expansion of the stent 10.

[0061] The material that constitutes the porous structure 20 is not particularly limited, but it can be made of, for example, a metal or a polymer.

[0062] As the metal constituting the porous structure 20, for example, the metals exemplified as the constituent materials of the stent 10 described above can be used.

[0063] Examples of the polymer that can be used to form the porous structure 20 include the following materials: (1) a polymer selected from the group consisting of aliphatic polyesters, polyesters, polyanhydrides, polyorthoesters, polycarbonates, polyphosphazenes, polyphosphates, polyvinyl alcohols, polypeptides, polysaccharides, proteins, and cellulose; and (2) copolymers composed of two or more types of monomers that form the above (1). The aliphatic polyester is not particularly limited, and examples thereof include polylactic acids (PLA) such as poly-L-lactic acid (PLLA), poly-D-lactic acid (PDLA), and poly-DL-lactic acid (PDLLA), polyglycolic acid (PGA), polyhydroxybutyric acid, polyhydroxyvaleric acid, polyhydroxypentanoic acid, polyhydroxyhexanoic acid, polyhydroxyheptanoic acid, poly(ε-caprolactone) (PCL), polytrimethylene carbonate, poly2,2-dimethyltrimethylene carbonate, polydioxanone, polybutyrolactone, polyvalerolactone, polymalic acid, polyethylene adipate, polyethylene succinate, polybutylene adipate, and polybutylene succinate. The polycarbonate is not particularly limited, and examples thereof include tyrosine-derived polycarbonate (Tyrosine-polycarbonate). Furthermore, polymers other than the biodegradable polymers mentioned above can also be used.

[0064] The thread diameter of the porous structure 20 (synonymous with the outer diameter of the skeletal portion 24b) is not particularly limited, but can be, for example, 20 μm.

[0065] Fig. 8 shows a schematic diagram of the drug coating layer 18 when the stent 10 is crimped onto the balloon 220. In Fig. 8, the skeleton 24b of the porous structure 20 is indicated by a two-dot chain line to simplify the illustration.

[0066] As shown in Figure 8, the drug coating layer 18 provided on the stent 10 has recesses 18a and protrusions 18b corresponding to the voids 24a and skeletal portion 24b of the porous structure 20. When the porous structure 20 is pressed against the outer surface of the drug coating layer 18 by a crimping method described below, the drug coating layer 18 is recessed to form recesses 18a in the portions corresponding to the skeletal portion 24b (portions pressed against the skeletal portion 24b). Furthermore, when the skeletal portion 24b is pressed, a portion of the drug coating layer 18 originally present in the recesses 18a moves (escapes) to the periphery. As a result, protrusions 18b are formed adjacent to the recesses 18a. As will be described in the crimping method described below, when the stent 10 is crimped onto the balloon 220, the porous structure 20 is pressed against the drug coating layer 18 to form the recesses 18a, thereby applying a uniform pressing force in the circumferential direction of the stent 10. This makes it possible to preferably prevent pinholes from occurring in the balloon 220.

[0067] Furthermore, at least a portion of the porous structure 20 is disposed in a state where it is embedded in the recesses 18a of the drug coating layer 18. In other words, the porous structure 20 is pressed against the drug coating layer 18, forming recesses 18a and protrusions 18b in the drug coating layer 18, and is disposed in a state where the skeletal portion 24b is embedded in the recesses 18a. When the stent 10 is crimped onto the balloon 220, the skeletal portion 24b of the porous structure 20 is embedded in the drug coating layer 18, thereby reducing the profile of the indwelling device 100.

[0068] The fixing portion 30 of the stent 10 can be provided, for example, so as to fix at least a part of the porous structure 20 to the stent 10 at a position excluding the distal end 10A and proximal end 10B of the stent 10. In this specification, the distal end 10A of the stent 10 refers to "the most distal end of the stent 10, in a region where the distalmost link portion 12 is not provided." Also, in this specification, the proximal end 10B of the stent 10 refers to "the most proximal end of the stent 10, in a region where the proximalmost link portion 12 is not provided."

[0069] The fixing portion 30 can be made of a weldable fixing material 50. For example, the fixing material 50 can be placed in the portion of the stent 10 where the fixing portion 30 is to be provided, and a part of the porous structure 20 can be embedded in the fixing material 50, thereby fixing the porous structure 20 to the stent 10.

[0070] The fixing material 50 used in the fixing part 30 can be, for example, the polymers exemplified as the materials constituting the porous structure 20 described above. It is particularly preferable to use a biodegradable polymer as the fixing material 50. With this configuration, the fixing material 50 is biodegraded in vivo after placement, thereby suppressing inflammation caused by the polymer. Note that, for example, wax can also be used as the fixing material 50.

[0071] The fixing parts 30 can be provided, for example, on all of the link parts 12 included in the stent 10. The link parts 12 undergo little change in axial geometry as the stent 10 expands in diameter. Therefore, in the link parts 12, tension does not occur in the porous structure 20 associated with the expansion of the diameter of the stent 10 when the stent 10 expands in diameter, and the fixing parts 30 provided on the link parts 12 can suitably prevent peeling or breakage of the porous structure 20.

[0072] As described above, the link portions 12 are not provided with the drug coating layer 18. Therefore, as shown in Fig. 6 , the fixing portion 30 is such that the porous structure 20 is directly fixed to the stent 10 at the exposed portion 19 of the stent 10 where no drug is applied. In other words, the fixing material 50 constituting the fixing portion 30 is directly fixed to the link portions 12 of the stent 10. With this configuration, the fixing strength of the porous structure 20 to the stent 10 when the fixing material 50 is fixed (welded) can be improved compared to a configuration in which the fixing material 50 is fixed to the stent 10 via the drug coating layer 18.

[0073] As described above, the fixing part 30 is configured by directly fixing the porous structure 20 to the stent 10 at the exposed part 19 of the stent 10 where no drug is applied. Therefore, even if the fixing part 30 is welded by heating, the absence of the drug coating layer 18 prevents the efficacy of the drug from being lost.

[0074] When fixing the fixing material 50 to the stent 10 via the drug coating layer 18, it is preferable to use a method that does not require heating or is less affected by heating, such as using an adhesive.

[0075] As shown in Fig. 6, the loop portions 21 of the mesh knitted along the circumferential direction of the porous structure 20 can be fixed to the stent 10. It is preferable that the portions fixed by the fixing portions 30 include at least the loop portions 21. With this configuration, the loop portions 21 extending along the circumferential direction can be fixed to the stent 10, so that a long distance of the porous structure 20 can be embedded in the fixing material 50, thereby improving the fixing force.

[0076] <Crimping device 400> Fig. 10 shows a schematic perspective view of crimping device 400 according to this embodiment. Figs. 12 to 15 show simplified front views of a portion of crimping device 400 (a portion including pressing member 410) when performing the crimping method.

[0077] The crimping device 400 is used to crimp the expandable tubular stent 10 onto the balloon 220 .

[0078] The crimping device 400 has at least one pressing member (crimp head) 410 that reduces the diameter of the stent 10 as it moves radially inward, thereby crimping the stent 10 onto a balloon 220 arranged on the inner side of the stent 10, a supply unit 420 that supplies sheet-like members 451, 452 between the pressing member 410 and the stent 10, and a heating unit 430 that heats the pressing member 410.

[0079] As shown in Figures 10 and 12, the crimping device 400 has a setting section 440 in which each component (balloon 220, stent 10, and porous structure 20; hereinafter referred to as "prepared item 100A") is set before being crimped.

[0080] 12 to 15, the pressing members 410 are arranged to surround the preparation 100A set in the setting section 440. In this embodiment, the crimping device 400 is configured to include ten pressing members 410. However, there is no particular limit to the number of pressing members 410 included in the crimping device 400.

[0081] As shown in FIGS. 12 to 15 , when the crimping method is performed, each pressing member 410 approaches the preparation item 100A set in the setting unit 440. As each pressing member 410 approaches the preparation item 100A, the space defined on the inside (diametrically inward) of the direction of movement of each pressing member 410 gradually decreases. Each pressing member 410 is provided with a pressing end 411 that applies a pressing force to the preparation item 100A during crimping. When each pressing member 410 approaches the preparation item 100A, the space defined on the inside of the pressing end 411 forms a substantially circular shape, and each pressing end 411 is pressed against the preparation item 100A. By further moving each pressing member 410 radially inward in this state, the pressing force applied to the preparation item 100A can be increased in accordance with the reduction in the diameter of the space defined on the inside of the pressing end 411. 13 to 15, the sheet-like members 451 and 452 used in the crimping device 400 are simply shown by two-dot chain lines.

[0082] The heating unit 430 heats each pressing member 410 to a predetermined temperature when crimping the preparation 100A. The heating unit 430 can be configured, for example, by a known heater or the like.

[0083] The supply unit 420 can be configured with a plurality of supply rollers 421, 422, 423 that supply sheet-like members 451, 452 between the outer periphery of the preparation 100A set in the setting unit 440 and each pressing member 410. In this embodiment, as shown in Fig. 12, when crimping the preparation 100A, two sheet-like members 451, 452 are supplied between the preparation 100A and the pressing ends 411 of each pressing member 410 so as to sandwich the preparation 100A. The crimping device 400 applies a pressing force from the outer surface side of the porous structure 20 located outermost of the preparation 100A by bringing each pressing member 410 close to the preparation 100A with the sheet-like members 451, 452 arranged between each pressing member 410 and the preparation 100A.

[0084] The sheet-like members 451, 452 can be made of, for example, a known resin sheet (polymer film) such as PTFE. However, there are no particular limitations on the material, thickness, number of sheets used during crimping, outer shape, structure, etc. of the sheet-like members. Furthermore, the sheet-like members 451, 452 may be provided with a structure having the same function as the void portion 24a and skeletal portion 24b of the porous structure. In other words, the sheet-like members can also be made of a porous structure. When the sheet-like member is made of a porous structure, the supply unit 420 functions as a supply unit for supplying the porous structure.

[0085] The operation of each part of the crimping device 400 can be controlled by a control unit including a CPU, etc. Furthermore, the crimping device 400 can be configured to be remotely controlled in response to commands from an external input device. For the configuration of the crimping device 400 not specifically described, any configuration of a crimping device known in the field of stent manufacturing methods can be adopted.

[0086] <Crimping Method> Next, a crimping method according to this embodiment (hereinafter also simply referred to as "crimping method") will be described with reference to FIGS.

[0087] FIG. 11 is a flowchart showing the steps of the crimping method.

[0088] The crimping method is a method of crimping the diameter-expandable cylindrical stent 10 onto the balloon 220 using at least one or more pressing members 410 configured to be movable radially inward.

[0089] Specifically, as shown in FIG. 11 , the crimping method includes placing the stent 10 on the outer periphery of the balloon 220 (hereinafter referred to as the “placement step S1”), compressing the diameter of the stent 10 by pressing a heated pressing member 410 from the outer surface side of the porous structure 20 covering the outer periphery of the stent 10 (hereinafter referred to as the “pressing step S2”), and pressurizing the inner cavity 225 of the balloon 220 at least once (hereinafter referred to as the “pressuring step S3”).

[0090] In this embodiment, the stent to be crimped is exemplified by the stent 10 (see FIG. 7) having the aforementioned drug coating layer 18. Furthermore, the porous structure 20 constituting the aforementioned indwelling device 100 is exemplified as the porous structure disposed between the stent 10 and the pressing member 410. Furthermore, the crimping device 400 described above is exemplified as the crimping device that realizes the crimping method.

[0091] The crimping method will be described in detail below.

[0092] An arrangement step S1 is performed before setting the preparation 100A in the crimping device 400. In the arrangement step S1, the stent 10 is arranged on the outer periphery of the balloon 220. Specifically, as shown in Fig. 13 , the balloon 220 is arranged on the inner periphery (diametrically central side) of the multiple pressing members 410, and the stent 10 is arranged so as to cover the outer periphery of the balloon 220.

[0093] In the preparation 100A, at least a portion of the porous structure 20 is fixed to the stent 10 in advance by the fixing portion 30 (see FIG. 6 ). Therefore, the stent 10 is set in the crimping device 400 in a state where the porous structure 20 is fixed to the stent 10.

[0094] There is no particular limitation on the timing for setting the porous structure 20 in the crimping device 400. For example, the porous structure 20 may be disposed on the outer periphery of the stent 10 after the balloon 220 and the stent 10 are set in the crimping device 400.

[0095] With the prepared item 100A set in the crimping device 400, sheet-like members 451, 452 are placed between the porous structure 20 and the pressing member 410. In this embodiment, two sheet-like members 451, 452 are used, and the prepared item 100A is sandwiched between the sheet-like members 451, 452. With the prepared item 100A sandwiched between the sheet-like members 451, 452, the crimping device 400 applies a predetermined tension to the sheet-like members 451, 452.

[0096] Next, a pressing step S2 is carried out. As shown in Fig. 13 , a plurality of pressing members 410 heated to a predetermined temperature are moved radially inward to press the porous structure 20 from the outer surface side. In this embodiment, since sheet-like members 451 and 452 are used, the pressing members 410 are pressed against the preparation 100A from the outer surface side of the porous structure 20 with the sheet-like members 451 and 452 interposed therebetween.

[0097] In the pressing step S2, there is no particular limitation on the timing to start heating the pressing member 410. For example, heating may be started immediately before the pressing member 410 is moved toward the porous structure 20, or the pressing member 410 may be preheated before the stent 10 and the porous structure 20 are set in the crimping device 400.

[0098] The heating temperature of the pressing member 410 during the pressing step S2 can be set to, for example, higher than 25°C and lower than 55°C.

[0099] When the balloon 220 is made of an organic polymer material, it is preferable that the lower limit of the heating temperature of the pressing member 410 be equal to or higher than the glass transition point of the material that constitutes the balloon 220. As an example, when the balloon 220 is made of a polymer material such as polyamide elastomer, polyurethane, or polyurethane elastomer, the lower limit of the heating temperature can be set to a temperature higher than the glass transition point of the polymer material and general room temperature (25°C). In other words, the lower limit of the heating temperature can be set to a temperature higher than 25°C. As a result, when the pressing member 410 is heated, the balloon 220 becomes more flexible than when not heated, and the profile of the balloon 220 is reduced.

[0100] Furthermore, when the porous structure 20 is made of a polymer as described above, the lower limit of the heating temperature of the pressing member 410 is preferably equal to or higher than the glass transition point of the material constituting the porous structure 20. For example, when the porous structure 20 is made of an aliphatic polyester (preferably polyglycolic acid (PGA)), the lower limit of the heating temperature can be set to the glass transition point, 40° C. As a result, when the pressing member 410 is heated, the state of engagement between the porous structure 20 and the stent 10 becomes greater than when not heated, and the profile of the outer diameter of the prepared product 100A is reduced.

[0101] Furthermore, when the stent 10 is provided with a drug coating layer 18, the upper limit of the heating temperature of the pressing member 410 is preferably a temperature that does not significantly affect the elution of the drug coating layer 18. When the stent 10 is provided with a drug coating layer 18 made of the above-mentioned materials, the upper limit of the heating temperature can be, for example, 54°C.

[0102] While the pressing step S2 is being performed, the pressurizing step S3 can be performed at least once. By performing the pressurizing step S3, the balloon 220 expands radially outward, and a portion of the balloon 220 enters the gaps in the stent 10 (the gaps formed between the strut portions 14, 15, 16 and the curved portion 17). This improves the crimping force that holds the stent 10 against the balloon 220, while reducing the profile of the crimped indwelling device 100. The pressurizing step S3 may be performed when the pressing step S2 is not being performed. The timing at which the pressurizing step S3 is started, the number of times it is performed, the pressure in the lumen 225 of the balloon 220 during pressurization, and the like can be set as desired depending on the product specifications of the indwelling device 100.

[0103] The stent 10 according to this embodiment has a drug coating layer 18 disposed on the outer surface 10b of the stent 10, the outer surface 10b facing the porous structure 20. Therefore, when the pressing member 410 is pressed against the outer surface of the porous structure 20 in the pressing step S2, recesses 18a and protrusions 18b corresponding to the porous structure 20 are formed in the drug coating layer 18 (see FIG. 8 ). Specifically, in the drug coating layer 18, in the portion corresponding to the skeletal portion 24b of the porous structure 20 (the portion pressed by the skeletal portion 24b), recesses 18a are formed that are recessed more than the surrounding portion. Furthermore, in the drug coating layer 18, in the portion corresponding to the void portion 24a of the porous structure 20, protrusions 18b that are protruding more than the recesses 18a are formed. As a result, the porous structure 20 is embedded in the drug coating layer 18, and the resistance to circumferential or axial displacement from the state in which the porous structure 20 is placed on the stent 10 is greater than when the porous structure 20 is not embedded in the drug coating layer 18.

[0104] Furthermore, in the crimping method of this embodiment, the pressing step S2 is performed with the porous structure 20 disposed between the pressing member 410 and the stent 10. By disposing the porous structure 20 between the pressing member 410 and the stent 10, it is possible to increase the frictional force generated between the pressing member 410 and the porous structure 20 when crimping the stent 10 onto the balloon 220, compared to when the pressing member 410 is directly pressed against the stent 10. This effect of increasing the frictional force is achieved because the mesh size of the skeleton 24b of the porous structure 20 is smaller than that of the stent 10. By disposing the porous structure 20 between the pressing member 410 and the stent 10 as described above and performing the pressing step S2 with a larger frictional force generated between the pressing member 410 and the porous structure 20, it is possible to prevent the porous structure 20 from slipping on the stent 10 and becoming displaced when a pressing force is applied by the pressing member 410 to the sheet-like members 451, 452. This allows the pressing member 410 to apply a uniform pressing force to each portion of the stent 10 in the circumferential direction.

[0105] Furthermore, in the crimping method of this embodiment, when a pressing force is applied to the porous structure 20 by the pressing member 410 in the pressing step S2, the porous structure 20 is uniformly reduced in diameter along the circumferential direction by reducing the gaps between the voids 24a of the porous structure 20 or by moving the skeletal portion 24b so that the overlap between the voids 24a increases. At this time, the porous structure 20 is forced into the drug coating layer 18, and the circumferential reduction in diameter begins from a state in which the frictional force between the porous structure 20 and the stent 10 increases, so the diameter is uniformly reduced along the circumferential direction while the spacing between the struts (specifically, between the first strut portion 15 and the second strut portion 16, and between the first strut portion 15 and the third strut portion 14) is maintained. Therefore, when a pressing force is applied to the porous structure 20 by the pressing member 410, the porous structure 20 contracts in diameter uniformly along the circumferential direction, while applying a uniform pressing force to each portion in the circumferential direction of the stent 10 disposed on the inner periphery of the porous structure 20. This makes it difficult for any of the spaces between the struts to become extremely narrow, and prevents the force clamping the balloon 220 from becoming excessively strong. Therefore, the crimping method of this embodiment can effectively prevent pinholes from occurring in the balloon 220 in the pressing step S2.

[0106] Furthermore, in the crimping method of this embodiment, the pressing step S2 is performed with the pressing member 410 heated. Therefore, the porous structure 20 is pressed against the drug coating layer 18 disposed on the outer surface 10b of the stent 10 by the heated pressing member 410. The drug coating layer 18 is softened by the heat transferred from the pressing member 410. As a result, at least a portion of the porous structure 20 is positioned so as to be more deeply embedded in the drug coating layer 18 by the pressing step S2 than in a state without heating. This increases the resistance to circumferential or axial displacement between the porous structure 20 and the stent 10 compared to a state without heating, and enhances the effect of uniformly reducing the diameter of the gaps between the struts (specifically, between the first strut portion 15 and the second strut portion 16, and between the first strut portion 15 and the third strut portion 14) along the circumferential direction. This makes it even less likely that the gap between any of the struts will become extremely narrow during the pressing step S2, and prevents the force clamping the balloon 220 from becoming excessively strong, thereby more effectively preventing pinholes from occurring in the balloon 220.

[0107] Furthermore, in the crimping method of this embodiment, since pressing step S2 is performed while pressing member 410 is heated as described above, heat transferred from pressing member 410 softens both drug coating layer 18 and balloon 220. Therefore, the diameter-contracting force of balloon 220 from pressing member 410 during pressing step S2 reduces the gaps between folded portions 227 of balloon 220, resulting in closer spacing between folded portions 227. Therefore, the profile of balloon 220 is effectively reduced after pressing step S2.

[0108] In the crimping method of this embodiment, the pressing step S2 on the preparatory item 100A is performed with sheet-like members 451, 452 disposed between the porous structure 20 and the pressing member 410. The sheet-like members are made of polymer film. When the pressing end 411 of each pressing member 410 contacts the preparatory item 100A as the pressing member 410 moves radially inward, the sheet-like members 451, 452 function as buffer members for shaping the space defined inside the pressing end 411 into a shape closer to a circle. For example, as shown in FIGS. 13 to 15 , if the space defined inside the pressing end 411 of each pressing member 410 (the space in which the preparatory item 100A is set) is shaped like a polygon according to the cross-sectional shape of the pressing end 411, and the pressing end 411 contacts the preparatory item 100A, gaps are formed at the corners (vertices) of the polygon that do not contact the preparatory item 100A. If the pressing step S2 is performed with such a gap formed, the pressing force cannot be applied appropriately to the entire circumferential range of the preparation 100A, and the pressing force cannot be applied along the circular cross section of the preparation 100A. As a result, the profile of the living body indwelling device 100 cannot be sufficiently reduced. In this embodiment, by performing the pressing step S2 with the sheet-like members 451, 452 disposed between the pressing member 410 and the preparation 100A, the influence of the gap formed between the preparation 100A and the pressing end 411 of the pressing member 410 as described above can be reduced. Therefore, the profile of the living body indwelling device 100 after the pressing step S2 can be effectively reduced.

[0109] After the profile of the indwelling device 100 reaches a predetermined size by performing the pressing step S2 and (at least once) the pressurizing step S3, the pressing member 410 is moved radially outward. By moving the pressing member 410 radially outward, the application of the pressing force to the indwelling device 100 is released. The crimping method of this embodiment can be completed by the above procedure. In addition, a method for manufacturing the indwelling device 100 using the crimping method described above and a method for manufacturing a balloon catheter 200 (stent delivery system 300) including components other than the indwelling device 100 are also provided.

[0110] As described above, the crimping method according to this embodiment is a crimping method for crimping an expandable cylindrical stent 10 onto a balloon 220 using at least one pressing member 410 configured to be movable radially inward, and includes placing the stent 10 on the outer periphery of the balloon 220, pressing the heated pressing member 410 from the outer surface side of the porous structure 20 covering the outer periphery of the stent 10 to reduce the diameter of the stent 10, and pressurizing the inside of the balloon 220 at least once.

[0111] In the crimping method according to this embodiment, the porous structure 20 is placed so as to cover the outer periphery of the stent 10, and the heated pressing member 410 is pressed from the outer surface side of the porous structure 20 to reduce the diameter of the stent 10, and further, by pressurizing the inside of the balloon 220 at least once, it is possible to improve the crimping force of the indwelling device 100, reduce the profile of the indwelling device 100, and reduce the incidence of pinholes.

[0112] Furthermore, the living body implant 100 according to this embodiment is a living body implant placed on the outer periphery of an expandable and contractible balloon 220, and comprises an expandable cylindrical stent 10 crimped onto the outer periphery of the balloon 220, and a porous structure 20 placed so as to cover the stent 10 and at least a portion of which is fixed to the stent 10, the stent 10 having a drug coating layer 18 placed on the outer surface 10b of the surface of the stent 10 that faces the porous structure 20, the porous structure 20 having voids 24a penetrating through the thickness of the porous structure 20 and a skeletal portion 24b that defines the voids 24a, and the drug coating layer 18 having concave portions 18a and convex portions 18b corresponding to the voids 24a and skeletal portion 24b of the porous structure 20.

[0113] According to the implant device 100 configured as described above, when the stent 10 is crimped onto the balloon 220, the porous structure 20 is pressed against the drug coating layer 18 so as to form the recesses 18a, thereby applying a uniform pressing force in the circumferential direction of the stent 10. Therefore, the implant device 100 can reduce the incidence of pinholes while improving the crimping force and reducing the profile.

[0114] In addition, the crimping device 400 of this embodiment has at least one pressing member 410 that reduces the diameter of the stent 10 as it moves radially inward, thereby crimping the stent 10 onto the balloon 220 arranged on the inner side of the stent 10, and a supply unit 420 that supplies at least one porous structure (e.g., a sheet-like porous structure) between the pressing member 410 and the stent 10.

[0115] According to the crimping device 400 configured as described above, when a pressing force is applied from the pressing member 410 to the sheet-like porous structure in the pressing step S2, the sheet-like porous structure reduces in diameter uniformly along the circumferential direction by narrowing the gaps in the voids of the porous structure on the sheet or by moving the framework so that the overlap between the voids increases. Therefore, when a pressing force is applied to the sheet-like porous structure by the pressing member 410, the sheet-like porous structure reduces in diameter uniformly along the circumferential direction while applying a uniform pressing force to each circumferential portion of the stent 10 disposed on the inner periphery of the sheet-like porous structure. This makes it difficult for any of the spacings between the struts to become extremely narrow, preventing the force clamping the balloon 220 from becoming excessively strong. Therefore, by supplying the sheet-like porous structure from the supply unit 420 in the crimping method using the crimping device 400, the formation of pinholes in the balloon 220 can be effectively prevented in the pressing step S2.

[0116] As explained in the above-described embodiment, the crimping method according to the present invention can be modified as desired as long as it includes the steps of "arranging a porous structure so as to cover the outer periphery of a stent, pressing a heated pressing member from the outer surface side of the porous structure to reduce the diameter of the stent, and pressurizing the inside of the balloon at least once." For example, the following modifications can be adopted.

[0117] In the above-described embodiment, an example was described in which the porous structure 20 used as a component of the indwelling device 100 was arranged to cover the outer periphery of the stent 10 when pressing with the pressing member 410 was performed. However, the porous structure used in the crimping method of the present invention is not limited to the porous structure 20 described above. For example, the porous structure may be formed of a sheet-like member supplied from the crimping device 400 when pressing with the pressing member 410 is initiated. That is, the porous structure may be formed by providing a structure having the same functions as the void portion 24a and the skeletal portion 24b in a sheet-like member, and pressing with the pressing member 410 can be performed with the stent 10 covered by this porous structure. Thus, the crimping method according to the modified example can be defined as including "a porous structure formed of sheet-like members, and a pressing member is used to press the porous structure from the outer surface side with the stent sandwiched between a plurality of sheet-like members."

[0118] Even when a porous structure made of the above-described sheet-like member is used, the effects described in the above-described embodiment can be achieved, such as "By performing the pressing step S2 in a state where a greater frictional force is generated between the pressing member 410 and the porous structure, it is possible to prevent pinholes from occurring in the balloon 220," and "In the pressing step S2, the porous structure reduces the gaps in the voids of the porous structure or moves the skeletal portion, thereby uniformly reducing the diameter along each portion in the circumferential direction and applying a uniform pressing force to each portion in the circumferential direction of the stent 10 arranged on the inner periphery of the porous structure, thereby effectively preventing pinholes from occurring in the balloon 220."

[0119] The porous structure may also be formed, for example, from a tubular member having a lumen. As an example, a member similar to the tubular porous structure used as a component of the indwelling device 100 in the above-described embodiment may be used as a jig for pressing with the pressing member 410. In other words, the crimping method according to this modified example may include "a porous structure formed from a tubular member having a lumen, and a pressing member is pressed from the outer surface side of the porous structure with a stent inserted into the lumen of the porous structure."

[0120] When the porous structure constructed as described above is used, the same effects as those of the crimping method using the porous structure constructed from a sheet-like member can be achieved.

[0121] When the porous structure described in each of the above-mentioned modifications is used, the porous structure is not used as a constituent element of the indwelling device. Therefore, the indwelling device to which the crimping method using the porous structure described in each of the modifications is applied is composed of the balloon 220 and the stent 10 crimped to the balloon 220.

[0122] The crimping method, balloon catheter manufacturing method, indwelling device, and crimping device according to the present invention have been described above through the embodiments and modifications. However, the present invention is not limited to the content described in the specification and can be modified as appropriate.

[0123] For example, although the description in the specification exemplifies a stent having a drug coating layer, the stents to which the crimping method, balloon catheter manufacturing method, and crimping device of the present invention can be applied are not limited to those having a drug coating layer.

[0124] This application is based on Japanese Patent Application No. 2023-218896, filed on December 26, 2023, the disclosure of which is incorporated herein by reference in its entirety.

[0125] DESCRIPTION OF SYMBOLS 10 Stent 10b Outer surface of stent 11 Ring 12 Link portion 18 Drug coating layer 18a Concave portion 18b Convex portion 20 Porous structure 24a Void portion 24b Skeleton portion 30 Fixing portion 100 Living body indwelling device 100A Preparation 200 Balloon catheter 210 Catheter body portion 220 Balloon 225 Inner cavity of balloon 227 Folding portion of balloon 300 Stent delivery system 400 Crimping device 410 Pressing member 411 Pressing end 420 Supply portion 430 Heating portion 451 Sheet-like member 452 Sheet-like member S1 Placement process S2 Pressing process S3 Pressurization process

Claims

1. A crimping method for crimping an expandable tubular stent to a balloon using at least one pressing member configured to be movable radially inward, comprising: disposing the stent on the outer peripheral side of the balloon; reducing the diameter of the stent by pressing the heated pressing member from the outer surface side of a porous structure covering the outer periphery of the stent; and pressurizing the inside of the balloon at least once.

2. A drug coating layer is disposed on the surface of the stent facing the porous structure, and by pressing the pressing member against the porous structure, concave and convex portions corresponding to the porous structure are formed in the drug coating layer. The crimping method according to claim 1.

3. The crimping method according to claim 1 or 2, wherein the pressing member is pressed from the outer surface side of the porous structure in a state where the pressing member is heated to a temperature higher than 25°C and lower than 55°C.

4. The crimping method according to claim 1, wherein at least a part of the porous structure is pre-fixed to the stent before disposing the stent on the outer peripheral side of the balloon.

5. The crimping method according to claim 4, wherein the heated pressing member is pressed from the outer surface side of the sheet-like member and the outer surface side of the porous structure with a sheet-like member disposed between the porous structure and the pressing member.

6. The crimping method according to claim 1, wherein the porous structure is disposed so as to cover the outer periphery of the stent in a state where the stent is disposed on the outer peripheral side of the balloon.

7. The porous structure is composed of a sheet-like member, and the pressing member is pressed from the outer surface side of the porous structure in a state where the stent is sandwiched between a plurality of the sheet-like porous structures. The crimping method according to claim 6.

8. The porous structure is composed of a tubular member having a lumen, and the pressing member is pressed from the outer surface side of the porous structure with the stent inserted into the lumen of the porous structure. The crimping method according to claim 6.

9. A method for manufacturing a balloon catheter using the crimping method according to claim 1.

10. A biological implant disposed on the outer periphery of an expandable and contractible balloon, comprising: an expandable cylindrical stent crimped on the outer peripheral surface of the balloon; and a porous structure disposed so as to cover the stent and at least partially fixed to the stent. The stent has a drug coating layer disposed on a surface of the stent facing the porous structure. The porous structure has voids penetrating in the thickness direction of the porous structure and a framework portion partitioning the voids. The drug coating layer has recesses and protrusions corresponding to the voids and the framework portion.

11. The biological implant according to claim 10, wherein at least a part of the porous structure is disposed in a state of being embedded in the recess of the drug coating layer.

12. The biological implant according to claim 10, wherein the porous structure is made of metal or polymer.

13. The stent has a linear ring forming a cylindrical outer periphery with gaps formed, and a plurality of link portions connecting the rings in the gaps. The drug coating layer is not formed on the link portions, and the porous structure is fixed at least to the link portions. The biological implant according to any one of claims 10 to 12.

14. A crimping device for crimping an expandable cylindrical stent onto a balloon, comprising: at least one or more pressing members for crimping the stent onto the balloon disposed on the inner peripheral side of the stent by reducing the diameter of the stent as it moves radially inward; and a supply unit for supplying at least one or more porous structures between the pressing member and the stent.

15. The crimping device according to claim 14, further comprising a heating unit for heating the pressing member.

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