Balloon catheter and balloon catheter manufacturing method

Abstract

A balloon (13) of a balloon catheter (10) has a cylindrical straight tube section (13c) having the largest diameter when inflated. The straight pipe part (13c) is provided with a linear protruding part (20), and the linear protruding part (20) protrudes from the surface of the straight pipe part (13c) and extends linearly along the surface of the straight pipe part (13c). A rough surface region (25) is formed on each side surface (20b) of the linear protrusion (20), and the surface roughness of the rough surface region (25) is greater than the surface roughness of the surface of the straight pipe section (13c).

Description

[0001] Cross-references of related applications

[0002] This application is based on Japanese application No. 2022-192303 filed on November 30, 2022, and the contents thereof are incorporated herein by reference. Technical Field

[0003] The present invention relates to a balloon catheter and a method for manufacturing the balloon catheter. Background Art

[0004] In the past, balloon catheters were used in treatments such as PTA (percutaneous angioplasty) and PTCA (percutaneous coronary angioplasty). The balloon catheter has a balloon that can expand and contract on its front end. In the balloon catheter, the balloon is introduced in a contracted state into a part that is narrowed or occluded due to a lesion or the like generated in a blood vessel, and then the part is expanded by inflating the balloon. In addition, the balloon has: a cylindrical straight tube portion, which has the largest diameter when inflated; and a pair of tapered portions, which are provided on the base end side and the front end side of the straight tube portion and decrease in diameter toward the side away from the straight tube portion.

[0005] The balloon catheter is provided with a linear protrusion that protrudes from the surface of the straight tube portion of the balloon and extends linearly along the surface of the straight tube portion (for example, refer to Patent Document 1). In this balloon catheter, when the balloon is inflated at the lesion, the linear protrusion enters the lesion, thereby forming an incision at the lesion. Therefore, the lesion can be easily expanded by using the incision as an opportunity.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: International Publication No. 2020 / 255923 Summary of the invention

[0009] Problems to be solved by the invention

[0010] However, when the lesion in the body is expanded by inflating the balloon, it is conceivable that the balloon is pressed by the lesion and slips in the axial direction. In this case, the lesion may not be expanded smoothly using the balloon.

[0011] Therefore, in order to suppress the balloon from slipping when the balloon is inflated, it is considered to increase the surface roughness of the straight tube portion of the balloon. However, this will increase the sliding resistance when the balloon is introduced into a tube such as a blood vessel, and the permeability of the balloon in the tube may be reduced.

[0012] The present disclosure has been made in view of the above circumstances, and its main object is to provide a balloon catheter and a method for manufacturing the balloon catheter that can suppress a decrease in passability when the balloon is introduced into a tube and suppress slippage of the balloon when the balloon is inflated.

[0013] Means for solving problems

[0014] In order to solve the above-mentioned problems, a first disclosed balloon catheter includes a balloon that can be expanded and deflated, wherein the balloon has a cylindrical straight tube portion whose diameter is largest when expanded, and a linear protrusion is provided on the straight tube portion, which protrudes from the surface of the straight tube portion and extends linearly along the surface, wherein a rough surface area with a surface roughness greater than the surface roughness of the surface of the straight tube portion is formed on the surface of the linear protrusion.

[0015] According to the first disclosure, a linear protrusion is provided on the straight tube portion of the balloon, and a rough surface region having a surface roughness greater than that of the straight tube portion is formed on the surface of the linear protrusion. In this case, when the balloon is inflated and the linear protrusion contacts an expansion target such as a lesion, the rough surface region of the linear protrusion can be brought into contact with the expansion target. Thus, the balloon can be prevented from slipping when the balloon is inflated.

[0016] In addition, the surface roughness of the straight tube portion is smaller than the surface roughness of the rough surface area of ​​the linear protrusion. The surface of the straight tube portion is significantly larger than the surface of the linear protrusion. Therefore, in this case, the surface roughness of the straight tube portion is reduced, and the sliding resistance when the balloon is introduced into a tube such as a blood vessel can be reduced. In this way, the decrease in the passability of the balloon in the tube can be suppressed, and the balloon can be suppressed from slipping when the balloon is inflated.

[0017] The second disclosed balloon catheter is based on the first disclosed one, wherein the balloon has a blade portion, which is formed in a deflated state of the balloon and folded along the outer periphery of the balloon, and the linear protrusion extends along the axial direction of the balloon and is covered by the blade portion from the outer periphery when the balloon is deflated.

[0018] According to the second disclosure, since the linear protrusions are covered by the blades from the outer circumference when the balloon is deflated, the rough surface area of ​​the linear protrusions can be prevented from sliding against the tube wall when the balloon is introduced into the tube in a deflated state, thereby further preventing a decrease in the passability of the balloon.

[0019] The balloon catheter disclosed in the third disclosure is based on the second disclosure, wherein the rough surface area is formed only in the middle portion in the longitudinal direction of the linear protrusion, or the surface roughness decreases toward the end side in the longitudinal direction of the linear protrusion.

[0020] In the second disclosure, a situation in which the entire linear protrusion cannot be covered by the blade portion is assumed. For example, a situation in which the end side of the linear protrusion protrudes from the blade portion is assumed. Therefore, in view of this, in the third disclosure, a structure is adopted in which a rough surface area is formed only in the middle part of the length direction of the linear protrusion, or a structure in which the surface roughness decreases as it approaches the end side of the length direction of the linear protrusion.

[0021] According to the former structure, since the rough surface area is not formed on the end side of the linear protrusion in the length direction, when the balloon is introduced into the tube in a contracted state, even if the end side of the linear protrusion extends from the blade part and slides on the tube wall, the sliding resistance can be suppressed from increasing. Thus, the decrease in the permeability of the balloon can be further suppressed. In addition, according to the latter structure, the surface roughness of the rough surface area on the end side of the linear protrusion in the length direction becomes smaller. Therefore, the same effect as the former structure can be obtained.

[0022] A balloon catheter disclosed in a fourth disclosure is based on the first or second disclosure, wherein a plurality of the rough surface regions are formed on the surface of the linear protrusion, and the plurality of the rough surface regions are arranged densely toward the protruding tip of the linear protrusion.

[0023] When the balloon is inflated and the linear protrusion is brought into contact with an expansion object such as a lesion, the protruding front end side of the linear protrusion is mainly brought into contact with the expansion object such as the lesion. In this regard, in the fourth disclosure, a plurality of rough surface areas are formed on the surface of the linear protrusion and are arranged in a denser manner as they are closer to the protruding front end side of the linear protrusion. In this case, it is possible to appropriately suppress the balloon from slipping when the balloon is inflated. In addition, the plurality of rough surface areas are arranged in a sparser manner as they are closer to the protruding base end side of the linear protrusion (the side opposite to the protruding front end side), so that compared with the case where the rough surface areas are densely arranged on the entire surface area of ​​the linear protrusion, it is possible to reduce the sliding resistance when the balloon is introduced into the tube. As a result, it is possible to further suppress the reduction in the passability of the balloon, and to appropriately suppress the balloon from slipping.

[0024] A balloon catheter according to a fifth disclosure is provided in the first or second disclosure, wherein the surface roughness of the rough surface region increases toward the protruding tip end of the linear protrusion.

[0025] According to the fifth disclosure, the surface roughness of the rough surface area is larger as it is closer to the protruding front end side of the linear protrusion, so it is possible to appropriately suppress the balloon from slipping when the balloon is inflated. In addition, the surface roughness of the rough surface area is smaller as it is closer to the protruding base end side of the linear protrusion, so compared with the case where the surface roughness of the rough surface area as a whole is increased, the sliding resistance when the balloon is introduced into the tube can be reduced. Thus, similar to the fourth disclosure above, the decrease in the passability of the balloon can be further suppressed, and the balloon can be appropriately suppressed from slipping.

[0026] The sixth disclosed balloon catheter is based on the first or second disclosed, wherein the balloon has a pair of tapered portions, the pair of tapered portions are arranged on both sides of the straight tube portion, and the diameters are reduced toward the side away from the straight tube portion, the surface roughness of the surface of the tapered portion is greater than the surface roughness of the surface of the straight tube portion, and the surface roughness of the surface of the tapered portion is smaller than the surface roughness of the rough surface area.

[0027] When the diseased part is expanded by utilizing the tapered portion of the balloon, the tapered portion obliquely contacts the diseased part, and therefore, as a reaction, the tapered portion is obliquely pressed by the diseased part, and the balloon is likely to slip along the axial direction. In this regard, in the sixth disclosure, the surface roughness of the surface of the tapered portion is greater than the surface roughness of the surface of the straight tube portion. In this case, by the surface of the tapered portion contacting the diseased part, it is possible to suppress the tapered portion from slipping along the axial direction, and further suppress the balloon from slipping along the axial direction. In addition, since the surface roughness of the surface of the tapered portion is smaller than the surface roughness of the rough surface area of ​​the linear protrusion, it is possible to suppress the reduction in the passability when the balloon is introduced into the tube, and the above-mentioned effect can be obtained.

[0028] The seventh disclosed method for manufacturing a balloon catheter is the method for manufacturing the first disclosed method for manufacturing a balloon catheter, wherein a protrusion serving as a basis for the linear protrusion is provided on the outer peripheral surface of a tubular parison serving as a basis for the balloon, an internal space for forming the balloon is provided in a mold for manufacturing the balloon, the internal space has a space portion forming the straight tube portion, a groove portion for forming the linear protrusion is provided on a wall portion forming the space portion in an inner wall surface of the mold forming the internal space, a rough surface portion having a surface roughness greater than that of the wall portion portion is formed on the inner surface of the groove portion, and the method for manufacturing the balloon catheter includes an expansion step, in which the parison is expanded in the internal space so that the outer peripheral surface of the parison is closely attached to the inner wall surface, and the protrusion is pressed into the groove portion to form the linear protrusion, and in the expansion step, the rough surface area is formed on the surface of the linear protrusion by pressing the protrusion into the groove portion and making the protrusion closely attached to the rough surface portion.

[0029] According to the seventh disclosure, by expanding the parison in the internal space of the mold, the protrusion of the parison is pressed into the groove formed on the wall surface of the mold, thereby forming a linear protrusion. In addition, the protrusion of the parison is pressed into the groove, and is in close contact with the rough surface formed on the inner surface of the groove, thereby forming a rough surface area on the surface of the linear protrusion. In this case, since the rough surface area can be formed when the parison is expanded, after the parison is expanded to form a balloon with a linear protrusion, there is no need to perform subsequent processes such as cutting the surface of the linear protrusion to form a rough surface area. As a result, the balloon catheter of the first disclosure mentioned above can be manufactured relatively easily.

[0030] The eighth disclosed method for manufacturing a balloon catheter is based on the seventh disclosed method, wherein the expansion process includes: a first expansion process, in which the interior of the parison is pressurized with a first pressure to expand the parison and the protrusion enters the groove; and a second expansion process, after the first expansion process, in which the interior of the parison is pressurized with a second pressure higher than the first pressure to press the protrusion into the groove and make the protrusion close to the rough surface.

[0031] According to the eighth disclosure, during the expansion process, the parison is first expanded by pressurizing the inside of the parison with a relatively low first pressure, so that the protrusion of the parison enters the groove (first expansion process). In this case, the parison can be expanded relatively slowly, so the protrusion of the parison can reliably enter the groove. Then, the protrusion of the parison is pressed into the groove by pressurizing the inside of the parison with a second pressure higher than the first pressure, so that it is closely attached to the rough surface (second expansion process). In this case, the protrusion can be strongly pressed into the groove to make it closely attached to the rough surface. Therefore, the rough surface area can be appropriately formed on the surface of the linear protrusion.

[0032] A ninth disclosed method for manufacturing a balloon catheter is based on the eighth disclosed method, wherein in the first expansion step, the parison is heated at a first temperature, and in the second expansion step, the parison is heated at a second temperature higher than the first temperature.

[0033] According to the ninth disclosure, in the second expansion step, the parison is heated at a higher temperature (second temperature) than in the first expansion step. In this case, the protrusion of the parison can be pressed into the groove in a soft state, so that the protrusion can be easily brought into close contact with the rough surface. As a result, the rough surface area can be more appropriately formed on the linear protrusion.

[0034] The tenth disclosed method for manufacturing a balloon catheter is based on any one of the seventh to ninth disclosed methods, wherein the height of the protrusion is greater than the depth of the groove.

[0035] According to the tenth disclosure, since the height of the protrusion of the parison is greater than the depth of the groove, when the protrusion is pressed into the groove, the protrusion can be firmly pressed into the bottom of the groove so that it is in close contact with the rough surface. Thus, the rough surface area can be reliably formed to the protruding front end side of the linear protrusion. Therefore, the balloon can be appropriately prevented from slipping when the balloon is inflated.

[0036] The eleventh disclosed method for manufacturing a balloon catheter is based on any one of the disclosures from the seventh to the ninth, wherein the cross-section of the groove is a valley shape, the cross-section of the protrusion is a mountain shape, the inner surface of the groove includes two side surfaces forming the valley shape, the surface of the protrusion includes two side surfaces forming the mountain shape, and the angle formed by the side surfaces of the protrusion is larger than the angle formed by the side surfaces of the groove.

[0037] According to the eleventh disclosure, the cross section of the protrusion of the parison is in the shape of a mountain, and the cross section of the groove is in the shape of a valley. In addition, the angle formed by the side surfaces of the protrusion is larger than the angle formed by the side surfaces of the groove. In this case, when the protrusion is pressed into the groove, the protrusion can be deformed in a manner along the side surfaces of the groove, and firmly adhere to the above-mentioned side surfaces (and thus the rough surface). Therefore, the above-mentioned structure can be said to be a preferred structure in terms of forming a rough surface area in the linear protrusion of the mountain shape.

[0038] The manufacturing method of the balloon catheter of the twelfth disclosure is based on the eleventh disclosure, wherein the angle formed by the side surface of the groove with respect to the width direction of the groove is larger at the opening portion of the groove than at the portion of the groove further inside the opening portion.

[0039] In the above-mentioned eleventh disclosure in which the cross section of the groove portion is valley-shaped and the cross section of the protrusion portion is mountain-shaped, it is envisaged that after the protrusion portion enters the groove portion, the protrusion portion is offset along the side surface of the groove portion. In this case, there may be undesirable situations such as the inability to smoothly form a rough surface area on the side surface of the linear protrusion. Therefore, in view of such a point, in the open part of the groove portion, the angle formed by the side surface of the groove portion relative to the width direction of the groove portion is increased compared to the part of the groove portion that is closer to the inner side than the open part. In this case, it is possible to suppress the protrusion entering the groove portion from being offset along the side surface of the groove portion. Therefore, the above-mentioned undesirable situation caused by the offset of the protrusion can be suppressed.

[0040] The thirteenth disclosed method for manufacturing a balloon catheter is based on any one of the disclosures of the seventh to ninth, wherein the width of the groove decreases toward the bottom of the groove, the inner surface of the groove includes two adjacent side surfaces separated by the bottom, and during the expansion process, the protrusion is pressed into the groove in a manner that the protrusion first abuts against the side surfaces of the groove and then abuts against the bottom.

[0041] According to the thirteenth disclosure, when the protrusion is pressed into the groove, the protrusion can be deformed along the side surfaces of the groove and pressed into the bottom of the groove. In this case, the protrusion can be appropriately in close contact with the entire area of ​​the side surfaces of the groove (and thus the rough surface), and the rough surface area can be appropriately formed on the linear protrusion. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The above-mentioned object and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description with reference to the accompanying drawings.

[0043] Figure 1 It is a schematic overall side view showing the structure of a balloon catheter.

[0044] Figure 2 (a) is a side view showing the balloon in an expanded state and its surrounding structure, (b) is a cross-sectional view taken along line AA of (a), and (c) is a cross-sectional view showing an enlarged linear protrusion in (b).

[0045] Figure 3 It is a side view showing the balloon in an inflated state and its surrounding structure, and shows the balloon and the outer tube in a longitudinal cross-section.

[0046] Figure 4 (a) is a side view showing the balloon in a deflated state and its surrounding structure, and (b) is a cross-sectional view taken along line BB of (a).

[0047] Figure 5 (a) is a cross-sectional view showing the structure of the mold, (b) is a cross-sectional view taken along line CC of (a), and (c) is a cross-sectional view showing an enlarged groove portion in (b).

[0048] Figure 6 It is a perspective view showing a parison.

[0049] Figure 7 (a) is a cross-sectional view showing a state where the parison is expanded in the internal space of the mold, and (b) is a cross-sectional view taken along line DD of (a).

[0050] Figure 8 It is a cross-sectional view showing the flow when the protruding portion of the parison is pressed into the groove portion of the mold during the expansion step.

[0051] Fig. 9 It is a side view showing the structure of the balloon and its surroundings in another embodiment.

[0052] Fig.10 This is a side view showing an enlarged view of a linear protrusion having a rough surface region formed therein in another embodiment.

[0053] Fig.11It is a cross-sectional view showing a groove portion of a mold in another embodiment.

[0054] Fig.12 It is a side view showing the structure of the balloon and its surroundings in another embodiment. DETAILED DESCRIPTION

[0055] Hereinafter, one embodiment of the present disclosure will be described with reference to the drawings. Figure 1 It is a schematic overall side view showing the structure of a balloon catheter.

[0056] like Figure 1 As shown, the balloon catheter 10 includes a catheter body 11 , a hub 12 attached to a base end portion (proximal end portion) of the catheter body 11 , and a balloon 13 attached to a distal end portion (distal end portion) of the catheter body 11 .

[0057] The catheter body 11 includes an outer tube 15 and an inner tube 16 that penetrates the inner portion of the outer tube 15. The outer tube 15 is formed into a tubular shape by a resin material and has an inner cavity 15a extending in the entire axial direction (see Figure 3 ). The base end of the outer tube 15 is joined to the sleeve 12, and the front end of the outer tube 15 is joined to the balloon 13. In addition, the inner cavity 15a of the outer tube 15 is connected to the inside of the sleeve 12 and to the inside of the balloon 13. The inner cavity 15a of the outer tube 15 serves as a fluid lumen through which the compressed fluid flows when the balloon 13 is expanded or deflated.

[0058] It should be noted that the outer tube 15 may be formed by mutually joining a plurality of tubes arranged in the axial direction. In this case, the tube on the base end side of the plurality of tubes may be formed of a metal material, and the tube on the front end side may be formed of a resin material.

[0059] The inner tube 16 is formed of a resin material into a tubular shape and has an inner cavity 16a extending in the entire axial direction (see Figure 3 ). The base end of the inner tube 16 is joined to the middle position of the outer tube 15 in the axial direction. In addition, a portion of the front end side of the inner tube 16 extends further to the front end side than the outer tube 15, and the extended portion penetrates the inside of the balloon 13. Moreover, the vicinity of the front end of the inner tube 16 is joined to the front end of the balloon 13.

[0060] The inner lumen 16a of the inner tube 16 becomes a guidewire lumen for the guidewire G to pass through. The base end opening 18 of the inner lumen 16a is present in the middle of the axial direction of the balloon catheter 10. Therefore, the present balloon catheter 10 is an RX type catheter. It should be noted that the base end opening 18 of the inner lumen 16a may also be located at the base end of the balloon catheter 10. In this case, the balloon catheter 10 is an over the wire type catheter.

[0061] Next, based on Figure 2 to Figure 4 The balloon 13 and its peripheral structure will be described. Figure 2 (a) is a side view showing the balloon 13 in an expanded state and its surrounding structure, (b) is a cross-sectional view taken along line AA of (a), and (c) is a cross-sectional view showing the linear protrusion 20 in (b) in an enlarged manner. Figure 3 1 is a side view showing the balloon 13 and its surrounding structure in an expanded state, showing the balloon 13 and the outer tube 15 in a longitudinal cross-section. Figure 4 (a) is a side view showing the balloon 13 in a deflated state and its surrounding structure, and (b) is a cross-sectional view taken along line BB of (a).

[0062] The balloon 13 is formed of a thermoplastic resin material, for example, a polyamide elastomer. Figure 2 (a) and Figure 3 As shown, the balloon 13 is formed as a tube (tubular) with a circular cross section as a whole. Specifically, the balloon 13 has a base end side branch tube portion 13a, a base end side tapered portion 13b, a straight tube portion 13c, a front end side tapered portion 13d and a front end side branch tube portion 13e, and these portions 13a to 13e are arranged in the above order from the base end side to the front end side.

[0063] The base-side branch tube portion 13a is joined to the front end portion of the outer tube 15. The base-side tapered portion 13b expands in diameter from the front end portion of the base-side branch tube portion 13a toward the front end side and is tapered. The straight tube portion 13c extends from the front end portion of the base-side tapered portion 13b toward the front end side with a constant diameter and is in a circular tube (cylindrical) shape. The straight tube portion 13c is the portion with the largest diameter when the balloon 13 is inflated. The front-end tapered portion 13d decreases in diameter from the front end portion of the straight tube portion 13c toward the front end side and is tapered. The front-end branch tube portion 13e is joined to the front end side of the inner tube 16.

[0064] When compressed fluid is supplied to the inside of the balloon 13 through the inner cavity 15a of the outer tube 15, the balloon 13 is inflated. On the other hand, when negative pressure is applied to the inner cavity 15a of the outer tube 15 to discharge the compressed fluid from the inside of the balloon 13, the balloon 13 is in a deflated state. Figure 4 As shown in (a) and (b) of the present invention, the balloon 13 has a plurality of (three in the present embodiment) blade portions 21 formed in a deflated state. These blade portions 21 are arranged at predetermined intervals (specifically, at equal intervals) in the circumferential direction of the balloon 13. Each blade portion 21 is formed to extend in the axial direction across each tapered portion 13b, 13d and the straight tube portion 13c of the balloon 13. When the balloon 13 is in a deflated state, these blade portions 21 are folded along the outer circumference of the balloon 13, respectively, and are wound around the inner tube 16.

[0065] Note that a pair of contrast rings 19 are attached to the inner side of the balloon 13 in the inner tube 16. The contrast rings 19 are used to improve the visibility of the balloon 13 under X-ray projection and facilitate positioning of the balloon 13 at the target treatment site.

[0066] In the present balloon catheter 10, a linear protrusion 20 extending linearly along the surface of the straight tube portion 13c of the balloon 13 is provided. The linear protrusion 20 is used to form an incision in the lesion when the lesion is expanded by inflating the balloon 13. In the present balloon catheter 10, the incision is formed in the lesion by the linear protrusion 20, so that the lesion is easily expanded by the incision. Therefore, the present balloon catheter 10 becomes a balloon catheter with a scoring function.

[0067] The linear protrusions 20 protrude from the surface of the straight tube portion 13c and extend along the surface in the axial direction of the balloon 13. Specifically, the linear protrusions 20 extend over the entire region in the axial direction of the straight tube portion 13c. A plurality of linear protrusions 20 are arranged at predetermined intervals (specifically, at equal intervals) in the circumferential direction of the balloon 13, and three linear protrusions 20 are arranged in this embodiment. In addition, each linear protrusion 20 is formed integrally with the balloon 13.

[0068] The cross section of each linear protrusion 20 (specifically, a cross section orthogonal to the length direction of the linear protrusion 20) is in the shape of a mountain protruding radially outward from the balloon 13, specifically, in the shape of a triangle. In the linear protrusion 20, the end portion on the protruding front end side is a top portion 20a. The linear protrusion 20 has two side surfaces 20b adjacent to each other across the top portion 20a.

[0069] A rough surface region 25 having a surface roughness greater than that of the surface of the straight tube portion 13c is formed on each side surface 20b of the linear protrusion 20. The rough surface region 25 is provided on each linear protrusion 20. Figure 2 In (a), the rough surface area 25 is indicated by dotted hatching. The rough surface area 25 is formed in the entire area of ​​each side surface 20b of the linear protrusion 20 (that is, the entire surface area of ​​the linear protrusion 20), and its surface roughness is constant in the entire area of ​​the rough surface area 25. In addition, the surface roughness of the rough surface area 25 of each linear protrusion 20 is the same. It should be noted that the surface roughness of the surface of the balloon 13 is constant in the entire surface area of ​​the balloon 13.

[0070] In addition, in this specification, "surface roughness" means the arithmetic mean roughness Ra specified in JIS B0601: 2001. The arithmetic mean roughness Ra is measured in accordance with JIS B0633: 2001, and the measurement is performed using a measuring machine specified in JIS B0651: 2001.

[0071] Next, the method for manufacturing the balloon 13 is described. The balloon 13 is manufactured using the mold 30. Figure 5 The structure of the mold 30 will be described. Figure 5 (a) is a cross-sectional view showing the structure of the mold 30 , (b) is a cross-sectional view taken along line CC of (a), and (c) is a cross-sectional view showing the groove 35 in (b) in an enlarged manner.

[0072] like Figure 5 As shown in (a) of FIG. 1 , the mold 30 is formed into a rectangular parallelepiped shape, and has an internal space 31 in the mold 30 for forming the balloon 13. The internal space 31 is an elongated space extending in the longitudinal direction of the mold 30, and has a shape corresponding to the shape of the balloon 13. Figure 5 As shown in (b) of FIG. 1 , the cross-sectional shape of the internal space 31 (specifically, the shape of the cross section perpendicular to the longitudinal direction of the internal space 31 ) is circular over the entire region in the longitudinal direction.

[0073] The internal space 31 includes a space 31a forming the proximal side branch tube 13a of the balloon 13, a space 31b forming the proximal side tapered portion 13b, a space 31c forming the straight tube 13c, a space 31d forming the distal side tapered portion 13d, and a space 31e forming the distal side branch tube 13e. Each of these space portions 31a to 31e has a shape corresponding to each portion 13a to 13e of the balloon 13.

[0074] The mold 30 has an inner wall surface 32 that forms the inner space 31. The inner wall surface 32 is a surface that surrounds the inner space 31. The surface roughness of the inner wall surface 32 is constant throughout the entire area of ​​the inner wall surface 32. A plurality of (specifically, three) grooves 35 are formed on the inner wall surface 32a (equivalent to the wall surface) of the space portion 31c (equivalent to the "space portion" described in the technical solution) for forming the straight tube portion 13c in the inner wall surface 32. These grooves 35 extend in the longitudinal direction of the inner space 31 and are arranged at equal intervals in the circumferential direction of the inner wall surface 32.

[0075] like Figure 5As shown in (c), the cross section of each groove 35 (specifically, the cross section perpendicular to the longitudinal direction of the groove 35) is a valley shape, in other words, a V-shape. In addition, the cross-sectional shape of the groove 35 is a shape corresponding to the cross-sectional shape (mountain shape) of the linear protrusion 20. The groove 35 has two side surfaces 35b (equivalent to the inner surface of the groove 35) forming the above-mentioned valley shape. These side surfaces 35b are adjacent to each other across the bottom 35a (valley bottom) of the groove 35. In addition, in this case, the width of the groove 35 decreases as it approaches the bottom 35a of the groove 35.

[0076] A rough surface portion 36 having a surface roughness greater than that of the inner wall surface 32 (32a) is formed on each side surface 35b of the groove portion 35. The rough surface portion 36 is formed over the entire area of ​​each side surface 35b of the groove portion 35. In this case, the surface roughness of the rough surface portion 36 is constant over the entire area of ​​the rough surface portion 36. Figure 5 In (a), the rough surface portion 36 is indicated by dotted hatching.

[0077] Next, based on Figure 6 and Figure 7 A method for manufacturing the balloon 13 using the above-described mold 30 will be described. Figure 6 It is a perspective view showing the parison 37 . Figure 7 (a) is a cross-sectional view showing a state where the parison 37 is expanded in the internal space 31 of the mold 30 , and (b) is a cross-sectional view taken along line DD of (a).

[0078] When manufacturing the balloon 13, first, a preparation step of preparing the mold 30 and the parison 37 that will serve as the basis of the balloon 13 is performed. Figure 6 As shown, the parison 37 is formed into a circular tube shape by a resin material, for example, by extrusion molding. The parison 37 is provided with a plurality of (specifically three) protrusions 38 protruding from its outer peripheral surface. These protrusions 38 are the parts that form the basis of the linear protrusions 20 of the balloon 13. The cross section of the protrusion 38 (specifically, the cross section orthogonal to the length direction of the parison 37) is in the shape of a mountain protruding radially outward from the parison 37, specifically, a pentagonal shape (in other words, a home plate shape). Each protrusion 38 extends along the length direction of the parison 37, specifically, extending in the entire area of ​​the length direction of the parison 37. In addition, the protrusion 38 has two side surfaces 38b (equivalent to the surface of the protrusion 38) forming the above-mentioned mountain shape. These side surfaces 38b are adjacent to the top 38a of the protrusion 38.

[0079] Next, a placement step is performed to place the parison 37 in the internal space 31 of the mold 30. In this step, the parison 37 is placed in the internal space 31 with the longitudinal direction of the parison 37 facing the longitudinal direction of the internal space 31. Thus, the parison 37 is placed across the space portions 31a to 31e of the internal space 31. Then, an extension step is performed to extend the parison 37 in the longitudinal direction.

[0080] Then, if Figure 7 As shown in (a) and (b) of the present invention, the parison 37 is expanded in the internal space 31 of the mold 30, and the expansion process is performed to make the outer peripheral surface of the parison 37 close to the inner wall surface 32. In this process, the inside of the parison 37 is pressurized by introducing a pressurized fluid such as nitrogen into the parison 37, thereby expanding the parison 37. As a result, a parison expansion body 37A including the parts 13a to 13d of the balloon 13 is formed.

[0081] In the expansion process, a fluid supply device (not shown) is used to introduce a pressurized fluid into the interior of the parison 37. The fluid supply device can adjust the pressurization pressure in the parison 37 by adjusting the amount of the pressurized fluid introduced. In addition, in the expansion process, the parison 37 is expanded while being heated by a heater (not shown) provided in the mold 30. The heater can adjust the heating temperature of the parison 37.

[0082] In addition, during the expansion process, Figure 7 As shown in (b), by expanding the parison 37, each protrusion 38 of the parison 37 is pressed into each groove portion 35 of the mold 30, thereby forming each protrusion 38 into the shape of the linear protrusion 20 of the balloon 13. As a result, each linear protrusion 20 is formed on the straight tube portion 13c of the balloon 13. In addition, in the expansion step, by pressing the protrusion 38 of the parison 37 into the groove portion 35, the protrusion 38 is closely attached to each side surface 35b (each rough surface portion 36) of the groove portion 35, thereby forming a rough surface area 25 on each side surface 20b of the linear protrusion 20.

[0083] Next, based on Figure 8 The content of the expansion step will be described in more detail. Figure 8 It is a cross-sectional view showing a flow when the protrusion 38 of the parison 37 is pressed into the groove 35 of the die 30 during the expansion step.

[0084] First, based on Figure 8 (a) will explain the dimensional relationship between the protrusion 38 of the parison 37 and the groove 35 of the mold 30. Figure 8As shown in (a), the width W1 (maximum width) of the protrusion 38 is smaller than the width W2 (maximum width) of the groove 35. In addition, the height H1 of the protrusion 38 is greater than the depth H2 of the groove 35. It should be noted that the height H1 of the protrusion 38 refers to the height from the outer peripheral surface of the parison 37. In addition, the angle a formed by the side surfaces 38b of the protrusion 38 is greater than the angle b formed by the side surfaces 35b of the groove 35.

[0085] Next, the process of the expansion process is described. First, in the expansion process, Figure 8 As shown in (b) of FIG. 1 , a first expansion step is performed to expand the parison 37 so that each protrusion 38 of the parison 37 enters the groove 35. In the first expansion step, the parison 37 is expanded by pressurizing the inside of the parison 37 at a relatively low first pressure P1. In this case, the parison 37 can be expanded relatively slowly, so that the protrusion 38 can reliably enter the groove 35. In addition, the width W1 of the protrusion 38 is smaller than the width W2 of the groove 35, so it is easy to make the protrusion 38 enter the groove 35. In addition, in the first expansion step, the parison 37 is expanded while being heated at a relatively low first temperature T1.

[0086] In the first expansion step, the pressure in the parison 37 (that is, the first pressure P1) is increased relatively slowly, and the heating temperature of the parison 37 (that is, the first temperature T1) is increased relatively slowly. However, in the first expansion step, the pressure in the parison 37 may be kept constant, and the heating temperature of the parison 37 may be kept constant.

[0087] Then, if Figure 8 As shown in (c) of FIG. 1 , the second expansion step is performed as follows: the parison 37 is further expanded, and each protrusion 38 is pressed into the groove 35, thereby making each protrusion 38 closely attached to each side surface 35b (that is, the rough surface 36) of the groove 35. As a result, a rough surface region 25 is formed on each side surface 20b of the linear protrusion 20. In the second expansion step, the parison 37 is expanded by pressurizing the inside of the parison 37 with a second pressure P2 higher than the first pressure P1. In this case, the protrusion 38 can be strongly pressed into the groove 35 and closely attached to each side surface 35b. As a result, the rough surface region 25 can be appropriately formed on the linear protrusion 20.

[0088] In the second expansion step, the parison 37 is expanded while being heated at the second temperature T2 higher than the first temperature T1. In this case, the protrusion 38 of the parison 37 can be pressed into the groove 35 in a soft state, so that the protrusion 38 can be easily brought into close contact along the side surfaces 35b (rough surface 36) of the groove 35. Therefore, in this regard, the rough surface region 25 can be appropriately formed on the linear protrusion 20.

[0089] In the second expansion step, the pressure in the parison 37 (i.e., the second pressure P2) is increased faster than in the first expansion step, and the heating temperature of the parison 37 (i.e., the second temperature T2) is increased faster than in the first expansion step. However, in the second expansion step, the pressure in the parison 37 may be kept constant, and the heating temperature of the parison 37 may be kept constant.

[0090] In addition, since the angle a formed by the side surfaces 38b of the protrusion 38 is larger than the angle b formed by the side surfaces 35b of the groove 35, when the protrusion 38 is pressed into the groove 35, the protrusion 38 can be firmly attached to the side surfaces 35b (that is, the rough surface 36) while being deformed along the side surfaces 35b of the groove 35. Therefore, the rough surface region 25 can be appropriately formed on the mountain-shaped linear protrusion 20.

[0091] In addition, the angle a formed by the side surfaces 38b of the protrusion 38 is larger than the angle b formed by the side surfaces 35b of the groove 35, so that when the protrusion 38 is pressed into the groove 35, the protrusion 38 first abuts against the side surfaces 35b of the groove 35 (see Figure 8 (b)), and then abuts against the bottom 35a of the groove 35 (refer to Figure 8 (c)). In this case, the protrusion 38 can be pressed into the bottom 35a of the groove 35 while deforming the protrusion 38 along the side surfaces 35b of the groove 35. Therefore, the protrusion 38 can be appropriately in close contact with the entire area of ​​the side surfaces 35b of the groove 35 (and thus the rough surface area 36), and the rough surface area 25 can be appropriately formed on the linear protrusion 20.

[0092] It should be noted that during the expansion step, the portion of the protrusion 38 of the parison 37 that does not enter the groove 35 is pressed and flattened by the inner wall surface 32. Therefore, no linear protrusion 20 is formed in the portions 13a, 13b, 13d, and 13e other than the straight tube portion 13c.

[0093] After the expansion step, a cutting step is performed to cut off the remaining portions on both end sides of the parison expanded body 37A. Thus, the balloon 13 is formed, and the manufacture of the balloon 13 is completed.

[0094] Then, as subsequent steps, a step of joining the balloon 13 to the catheter body 11 and a step of joining the hub 12 to the catheter body 11 are performed. Thus, a series of manufacturing operations are completed.

[0095] Next, a method of using the balloon catheter 10 will be described. Here, a procedure for dilating a lesion formed in a blood vessel using the balloon catheter 10 will be described.

[0096] First, the guide catheter is inserted into the sheath introducer inserted into the blood vessel, and the front end opening of the guide catheter is introduced into the coronary artery entrance. Next, the guide wire G is inserted into the guide catheter, and the inserted guide wire G is introduced from the coronary artery entrance to the peripheral part through the lesion.

[0097] Next, the balloon catheter 10 is introduced into the guide catheter along the guide wire G. After the introduction, the balloon 13 is introduced (placed) toward the lesion while applying a push-pull operation. During the introduction, the balloon 13 is brought into a deflated state. In the deflated state of the balloon 13, the linear protrusion 20 is covered by the blade portion 21 from the outer peripheral side (see Figure 4 (b)). Therefore, when the balloon 13 is introduced, the rough surface area 25 formed on the linear protrusion 20 can be prevented from sliding against the tube wall. Thus, in the structure in which the rough surface area 25 is formed on the linear protrusion 20, the passability of the balloon 13 can be prevented from being reduced.

[0098] After the balloon 13 reaches the lesion, the balloon 13 is inflated. As a result, the linear protrusion 20 is pressed against the lesion, and a cut (crack) is formed in the lesion by the linear protrusion 20. Therefore, the lesion can be expanded outward by destroying the lesion with the cut as an opportunity. In addition, at this time, the rough surface area 25 of the linear protrusion 20 abuts against the lesion, so that the balloon 13 can be suppressed from slipping. Therefore, the lesion can be appropriately expanded at a desired position.

[0099] After the balloon 13 has completed dilation of the lesion, the balloon 13 is deflated. Then, the balloon catheter 10 is pulled out of the body in the deflated state. Thus, a series of operations are completed.

[0100] It should be noted that the balloon catheter 10 is mainly passed through blood vessels as described above, for example, for treating blood vessels such as coronary arteries, femoral arteries, and pulmonary arteries, but can also be used in "tubes" and "body cavities" in the body such as ureters and digestive tracts other than blood vessels.

[0101] According to the structure of this embodiment described in detail above, the following excellent effects can be obtained.

[0102] As described above, by making the rough surface area 25 of the linear protrusion 20 contact the lesion when the balloon 13 is inflated, the balloon 13 can be prevented from slipping. In addition, the surface roughness of the surface of the straight tube portion 13c of the balloon 13 is smaller than the surface roughness of the rough surface area 25 of the linear protrusion 20. The surface of the straight tube portion 13c is significantly larger than the surface of the linear protrusion 20, so in this case, the surface roughness of the surface of the straight tube portion 13c becomes smaller, thereby reducing the sliding resistance when the balloon 13 is introduced into the blood vessel. As a result, it is possible to prevent the decrease in the passability of the balloon 13 in the blood vessel, and further prevent the balloon 13 from slipping when the balloon 13 is inflated.

[0103] When the parison 37 is expanded and the protrusion 38 of the parison 37 is pressed into the groove 35 of the mold 30, the protrusion 38 is brought into close contact with the rough surface 36 formed in the groove 35, thereby forming the rough surface region 25 on each side surface 20b of the linear protrusion 20. In this case, after the parison 37 is expanded to form the balloon 13 having the linear protrusion 20, there is no need to perform subsequent steps such as cutting the side surface 20b of the linear protrusion 20 to form the rough surface region 25. Thus, the above-mentioned balloon 13 having the rough surface region 25 formed on the linear protrusion 20 can be manufactured relatively easily.

[0104] The present disclosure is not limited to the above-described embodiments, and may be implemented as follows, for example.

[0105] (1) In the above embodiment, the rough surface region 25 is formed on the entire surface of the linear protrusion 20 (specifically, the entire surface of each side surface 20b), but the rough surface region may be formed only on a portion of the surface of the linear protrusion 20. Fig. 9 .exist Fig. 9 In the example shown, each linear protrusion 40 is provided with a cutout 41. A plurality of (specifically, two) cutouts 41 are provided in each linear protrusion 40. In the linear protrusion 40, each cutout 41 is arranged at a position that divides the linear protrusion 40 substantially equally (specifically, into three equal parts).

[0106] The linear protrusion 40 is divided into a plurality of regions 40a to 40c by the cutouts 41. The regions 40a to 40c include a base end region 40a disposed on the base end side, a front end region 40b disposed on the front end side, and an intermediate region 40c disposed between the base end region 40a and the front end region 40b. A rough surface region 45 having a surface roughness greater than that of the surface of the straight tube portion 13c is formed on the surface of the intermediate region 40c among the regions 40a to 40c. On the other hand, the rough surface region 45 is not formed on the surface of the base end region 40a and the surface of the front end region 40b. Therefore, in this example, the rough surface region 45 is formed only in the intermediate region 40c in the linear protrusion 40.

[0107] According to the above structure, when the balloon 13 is introduced into the blood vessel in a contracted state, even if the front end side region 40b and the base end side region 40a of the linear protrusion 40 extend from the blade portion 21 and slide on the tube wall, the sliding resistance can be suppressed from increasing. Thus, the decrease in the permeability of the balloon 13 in the blood vessel can be further suppressed.

[0108] (2) In the structure of the above embodiment, the surface roughness of the rough surface region 25 may be made smaller as it approaches the end side in the longitudinal direction of the linear protrusion 20. For example, the surface roughness of the rough surface region 25 is made largest in the central part in the longitudinal direction of the linear protrusion 20. Furthermore, the surface roughness of the rough surface region 25 is made smaller from the central part in the longitudinal direction of the linear protrusion 20 toward one end, and is made smaller from the central part in the longitudinal direction of the linear protrusion 20 toward the other end. According to this structure, the same effect as that of the above (1) can be obtained.

[0109] (3) A plurality of rough surface regions may be formed on the surface of the linear protrusion. Fig.10 It should be noted that Fig.10 FIG. 4 is a side view showing an enlarged linear protrusion 50 having a plurality of rough surface regions 53 formed therein. Fig.10 In the example shown, a plurality of rough surface regions 53 are formed on each side surface 50a of the linear protrusion 50. Each rough surface region 53 extends along the longitudinal direction of the linear protrusion 50, and more specifically, the line extends over the entire region in the longitudinal direction of the linear protrusion 50. On the side surface 50a of the linear protrusion 50, each rough surface region 53 is arranged at a predetermined interval. In this case, each rough surface region 53 is arranged so that the interval between adjacent rough surface regions 53 becomes smaller as it approaches the protruding front end side of the linear protrusion 50. Therefore, each rough surface region 53 is arranged in a manner that it becomes denser as it approaches the protruding front end side of the linear protrusion 50.

[0110] When the balloon 13 is inflated and the linear protrusion 50 contacts the lesion, the protruding tip side of the linear protrusion 50 contacts the lesion. In this regard, according to the above-mentioned structure, the rough surface area 53 is arranged in a denser manner toward the protruding tip side of the linear protrusion 50, so that the balloon 13 can be appropriately suppressed from slipping when the balloon 13 is inflated.

[0111] In addition, the rough surface area 53 is arranged in a sparse manner toward the protrusion base end side (the side opposite to the protrusion tip side) of the linear protrusion 50, so that the sliding resistance when the balloon 13 is introduced into the blood vessel can be reduced compared to the case where the rough surface area 53 is densely arranged on the entire area of ​​each side surface 50a of the linear protrusion 50. Thus, the decrease in the passability of the balloon 13 can be further suppressed, and the balloon 13 can be appropriately suppressed from slipping.

[0112] (4) In the structure of the above-mentioned embodiment, the rough surface area 25 may be formed so that the surface roughness increases as it approaches the protruding front end side of the linear protrusion 20. In this case, it is possible to appropriately suppress the balloon 13 from slipping when the balloon 13 is inflated. In addition, when this structure is adopted, the surface roughness of the rough surface area 25 decreases as it approaches the protruding base end side of the linear protrusion 20. Therefore, compared with the case where the surface roughness of the rough surface area 25 as a whole is increased, the sliding resistance when the balloon 13 is introduced into the blood vessel can be reduced. As a result, similar to the structure of (3) above, the decrease in the passability of the balloon 13 can be further suppressed, and the balloon 13 can be appropriately suppressed from slipping.

[0113] (5) The dimensional relationship between the groove 35 of the mold 30 and the protrusion 38 of the parison 37 is not necessarily limited to the above-described embodiment. For example, the height H1 of the protrusion 38 may be smaller than the depth H2 of the groove 35, or may be equal to the depth H2 of the groove 35. In this case, the protrusion 38 can be reliably inserted into the groove 35 as a whole. In addition, the angle a formed by the side surfaces 38b of the protrusion 38 may be smaller than the angle b formed by the side surfaces 35b of the groove 35. In this case, the protrusion 38 of the parison 37 can be easily inserted into the groove 35.

[0114] (6) You can also Fig.11 The cross-sectional shape of the groove portion of the die 30 is changed as shown. Fig.11 In the example shown, similarly to the above-mentioned embodiment, the cross-sectional shape of the groove portion 55 is a valley shape. Therefore, the groove portion 55 has two side surfaces 56 forming a valley shape. The angle formed by these side surfaces 56 with respect to the width direction of the groove portion 55 changes in the middle. In detail, the above-mentioned angle changes between the side surface portion 56a of the open portion 55a of the groove portion 55 and the side surface portion 56b closer to the groove portion than the open portion 55a. Specifically, the angle c formed by the side surface portion 56a with respect to the width direction of the groove portion 55 is larger than the angle d formed by the side surface portion 56b with respect to the width direction of the groove portion 55. The angle c is, for example, 90°.

[0115] According to the above structure, during the expansion process, the protrusion 38 of the parison 37 entering the groove 55 can be prevented from being deviated along the side surface 56 of the groove 55. Thus, it is possible to prevent the occurrence of problems such as the rough surface area 25 not being smoothly formed on the side surface 20b of the linear protrusion 20 due to the protrusion 38 being deviated from the groove 55.

[0116] (7) However, when the lesion is expanded by the tapered portions 13b and 13d of the balloon 13, the tapered portions 13b and 13d contact the lesion obliquely, and as a reaction, the tapered portions 13b and 13d are pressed obliquely by the lesion, and the balloon 13 may slip in the axial direction. Fig.12 As shown, the surface roughness of the conical parts 13b and 13d of the balloon 13 may be greater than the surface roughness of the straight tube part 13c. In this case, the surfaces of the conical parts 13b and 13d contact the lesion part, which can prevent the conical parts 13b and 13d from slipping in the axial direction, and thus prevent the balloon 13 from slipping in the axial direction. It should be noted that Fig.12 In FIG. 1 , dotted shadows are marked on the surfaces of the tapered portions 13 b and 13 d.

[0117] In addition, Fig.12 In the example of FIG. 1 , the surface roughness of the surfaces of the tapered portions 13b and 13d is smaller than the surface roughness of the rough surface region 25 of the linear protrusion 20. Thus, the decrease in the permeability when the balloon 13 is introduced into the blood vessel can be suppressed, and the above-mentioned effect can be obtained. It should be noted that the surface roughness of only one of the tapered portions 13b and 13d can be increased.

[0118] (8) In the above embodiment, the linear protrusion 20 (first linear protrusion) protruding from the surface of the straight tube portion 13c of the balloon 13 is provided. Alternatively, a linear protrusion (second linear protrusion) protruding from the surface of the front end tapered portion 13d of the balloon 13 may be provided. In this case, a rough surface region having a surface roughness greater than that of the straight tube portion 13c may be formed on the surface of the second linear protrusion. In this way, the balloon 13 can be further prevented from slipping when the balloon 13 is inflated.

[0119] Similarly, a linear protrusion (third linear protrusion) protruding from the surface of the proximal tapered portion 13b of the balloon 13 may be provided, and a rough surface area having a surface roughness greater than that of the straight tube portion 13c may be formed on the surface of the third linear protrusion.

[0120] (9) In the above embodiment, the rough surface region 25 is formed on each side surface 20b of the linear protrusion 20 during the expansion step of expanding the parison 37, but the method of forming the rough surface region 25 is not necessarily limited to this. For example, after forming the balloon 13 having the linear protrusion 20, the side surface 20b of the linear protrusion 20 may be cut to form the rough surface region 25.

[0121] The present disclosure is described according to the embodiments, but the present disclosure is understood to be not limited to the embodiments and structures. The present disclosure also includes various modifications and variations within the equivalent range. In addition, various combinations, methods, and other combinations and methods including only one element, more elements than it, or fewer elements than it also fall within the scope of the present disclosure and the scope of thought.

[0122] Description of reference numerals:

[0123] 10…balloon catheter, 13…balloon, 13c…straight tube portion, 20…linear protrusion, 25…rough surface area, 30…mold, 31…inner space, 35…groove portion, 36…rough surface portion, 37…parison, 38…protrusion.

Claims

1. A balloon catheter comprising a balloon that can expand and contract, The balloon has a cylindrical straight tube portion having the largest diameter when inflated. The straight tube portion is provided with a linear protrusion that protrudes from a surface of the straight tube portion and extends linearly along the surface, wherein: A rough surface region having a surface roughness greater than that of the surface of the straight tube portion is formed on the surface of the linear protrusion.

2. The balloon catheter according to claim 1, wherein: The balloon has a blade portion, which is formed in a deflated state of the balloon and folded along the outer circumference of the balloon, The linear protrusion extends along the axial direction of the balloon, and is covered by the blade portion from the outer peripheral side when the balloon is in a deflated state.

3. The balloon catheter according to claim 2, wherein: The rough surface region is formed only in the middle portion in the longitudinal direction of the linear protrusion, or the surface roughness decreases toward the end side in the longitudinal direction of the linear protrusion.

4. The balloon catheter according to claim 1 or 2, wherein: The rough surface area is formed in plurality on the surface of the linear protrusion. The plurality of rough surface regions are arranged so as to be denser toward the protruding tip end side of the linear protrusion.

5. The balloon catheter according to claim 1 or 2, wherein: The closer the rough surface region is to the protruding tip side of the linear protrusion, the greater the surface roughness.

6. The balloon catheter according to claim 1 or 2, wherein: The balloon has a pair of tapered portions, which are arranged on both sides of the straight tube portion and decrease in diameter toward a side away from the straight tube portion. The surface roughness of the surface of the tapered portion is greater than the surface roughness of the surface of the straight tube portion. The surface roughness of the surface of the tapered portion is smaller than the surface roughness of the rough surface region.

7. A method for manufacturing a balloon catheter, which is a method for manufacturing the balloon catheter according to claim 1, wherein: A protrusion serving as a basis for the linear protrusion is provided on the outer peripheral surface of the tubular parison serving as a basis for the balloon. The mold used for manufacturing the balloon is provided with an inner space for forming the balloon. The internal space has a space portion forming the straight tube portion, A groove for forming the linear protrusion is provided on a wall portion forming the space portion of an inner wall surface forming the internal space of the mold, A rough surface portion having a surface roughness greater than that of the wall surface portion is formed on the inner surface of the groove portion. The method for manufacturing the balloon catheter includes an expansion step, in which the outer peripheral surface of the parison is closely attached to the inner wall surface by expanding the parison in the internal space, and the protrusion is pressed into the groove to form the linear protrusion. In the expansion step, the rough surface region is formed on the surface of the linear protrusion by pressing the protrusion into the groove and bringing the protrusion into close contact with the rough surface portion.

8. The method for manufacturing a balloon catheter according to claim 7, wherein: The expansion process comprises: a first expansion step of expanding the parison by pressurizing the interior of the parison with a first pressure, and causing the protrusion to enter the groove; and A second expansion step is performed after the first expansion step, in which the interior of the parison is pressurized at a second pressure higher than the first pressure to press the protrusion into the groove and bring the protrusion into close contact with the rough surface portion.

9. The method for manufacturing a balloon catheter according to claim 8, wherein: In the first expansion step, the parison is heated at a first temperature. In the second expansion step, the parison is heated at a second temperature higher than the first temperature.

10. The method for manufacturing a balloon catheter according to any one of claims 7 to 9, wherein: The height of the protrusion is greater than the depth of the groove.

11. The method for manufacturing a balloon catheter according to any one of claims 7 to 9, wherein: The cross section of the groove is valley-shaped, The cross section of the protrusion is mountain-shaped, The inner surface of the groove portion includes two side surfaces forming the valley shape, The surface of the protrusion includes two side surfaces forming the mountain shape, An angle formed by the side surfaces of the protrusion is larger than an angle formed by the side surfaces of the groove.

12. The method for manufacturing a balloon catheter according to claim 11, wherein: In the open portion of the groove, the angle formed by the side surface of the groove with respect to the width direction of the groove is larger than that of the portion of the groove further back than the open portion.

13. The method for manufacturing a balloon catheter according to any one of claims 7 to 9, wherein: The width of the groove portion decreases toward the bottom of the groove portion. The inner surface of the groove portion includes two side surfaces adjacent to each other across the bottom portion. In the expansion step, the protrusion is pressed into the groove portion so that the protrusion first comes into contact with the side surfaces of the groove portion and then comes into contact with the bottom portion.

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