Balloon catheter and method of manufacturing the same

Abstract

A balloon 13 of a balloon catheter 10 has a cylindrical straight pipe section 13c, the diameter of which becomes maximum when inflated. The straight pipe section 13c has provided thereto linear protrusions 20 that protrude from the surface of the straight pipe section 13c and linearly extend along the surface. Side surfaces 20b of each of the linear protrusions 20 have formed thereon coarse surface regions 25, the surface roughness of which is coarser than that of the surface of the straight pipe section 13c.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Application No. 2022-192303, filed on November 30, 2022, the contents of which are incorporated herein by reference. [Technical Field]

[0002] The present disclosure relates to balloon catheters and methods of manufacturing balloon catheters. [Background technology]

[0003] Balloon catheters have traditionally been used in treatments such as PTA (percutaneous transluminal angioplasty) and PTCA (percutaneous transluminal coronary angioplasty). A balloon catheter has an inflatable and deflated balloon at its distal end. With a balloon catheter, the balloon is introduced in a deflated state into a site narrowed or blocked by a lesion or other condition within a blood vessel, and then the balloon is inflated to expand the site. The balloon also has a cylindrical straight tube portion that is at its largest diameter when inflated, and a pair of tapered portions located at the proximal and distal ends of the straight tube portion and tapering in diameter toward the sides away from the straight tube portion.

[0004] Some balloon catheters are provided with linear protrusions that protrude from the surface of the straight tube portion of the balloon and extend linearly along the surface of the straight tube portion (see, for example, Patent Document 1). With such balloon catheters, when the balloon is inflated at the lesion, the linear protrusions can be caused to bite into the lesion, creating an incision in the lesion. This makes it easier to dilate the lesion using the incision as a trigger. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2020 / 255923 Summary of the Invention [Problem to be solved by the invention]

[0006] However, when dilating a lesion in the body by inflating a balloon, it is possible that the balloon may be pushed by the lesion and slip in the axial direction, which may result in the balloon not dilating the lesion properly.

[0007] To prevent the balloon from slipping during inflation, it is conceivable to increase the surface roughness of the straight portion of the balloon, but this increases the sliding resistance when the balloon is introduced into a vessel such as a blood vessel, potentially reducing the balloon's ability to pass through the vessel.

[0008] The present disclosure has been made in consideration of the above circumstances, and has as its main object to provide a balloon catheter and a method for manufacturing a balloon catheter that can suppress a decrease in passability when the balloon is introduced into a tube, while suppressing slippage of the balloon when the balloon is inflated. [Means for solving the problem]

[0009] In order to solve the above problems, the balloon catheter of the first disclosure is a balloon catheter equipped with an inflatable and deflated balloon, the balloon having a cylindrical straight tube portion that has the largest diameter when inflated, the straight tube portion having a linear protrusion that protrudes from the surface of the straight tube portion and extends linearly along the surface, and the surface of the linear protrusion is formed with a roughened surface region that has a surface roughness greater than that of the surface of the straight tube portion.

[0010] According to the first disclosure, a linear protrusion is provided on the straight tube portion of the balloon, and a roughened surface region with a rougher surface than the surface 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 is placed against a dilation target such as a lesion, the roughened surface region of the linear protrusion can be brought into contact with the dilation target. This makes it possible to prevent the balloon from slipping during inflation.

[0011] Furthermore, the surface roughness of the straight tube portion is smaller than that of the roughened surface region of the linear protrusion. Since the surface area of the straight tube portion is significantly larger than that of the linear protrusion, in this case, the reduced surface roughness of the straight tube portion can reduce the sliding resistance when the balloon is introduced into a vessel such as a blood vessel. This can prevent the balloon from slipping during inflation while suppressing a decrease in the balloon's passability through the vessel.

[0012] The balloon catheter of the second disclosure is the same as that of the first disclosure, except that the balloon has wing portions that are formed in its deflated state and are folded along the outer periphery of the balloon, and the linear protrusions extend in the axial direction of the balloon and are covered from the outer periphery by the wing portions when the balloon is deflated.

[0013] According to the second disclosure, when the balloon is deflated, the linear protrusions are covered from the outer periphery by the blades, which prevents the rough surface areas of the linear protrusions 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 balloon's passability.

[0014] The balloon catheter of the third disclosure is the balloon catheter of the second disclosure, wherein the rough surface region is formed only in the longitudinal middle portion of the linear protrusion, or the surface roughness decreases toward the longitudinal end portion of the linear protrusion.

[0015] In the second disclosure described above, it is conceivable that the entire linear protrusion cannot be covered by the blade portion. For example, it is conceivable that the end side of the linear protrusion protrudes from the blade portion. In view of this, the third disclosure adopts a configuration in which a rough surface region is formed only in the middle part of the linear protrusion in the longitudinal direction, or a configuration in which the surface roughness decreases toward the end side of the linear protrusion in the longitudinal direction.

[0016] According to the former configuration, since no rough surface region is formed on the longitudinal end side of the linear protrusion, even if the end side of the linear protrusion protrudes from the wing portion and slides against the tube wall when the balloon is introduced into the tube in a deflated state, it is possible to prevent an increase in sliding resistance. This further prevents a decrease in the balloon's passability. Furthermore, according to the latter configuration, the surface roughness of the rough surface region is reduced on the longitudinal end side of the linear protrusion. Therefore, the same effect as the former configuration can be obtained.

[0017] The balloon catheter of the fourth disclosure is the balloon catheter of the first or second disclosure, wherein the rough surface regions are formed in multiple areas on the surface of the linear protrusion, and the multiple rough surface regions are arranged so that they become denser toward the protruding tip of the linear protrusion.

[0018] When the balloon is inflated and the linear projections are brought into contact with a target for dilation, such as a lesion, the protruding tip side of the linear projections mainly comes into contact. In this regard, in the fourth disclosure, the rough surface regions formed on the surface of the linear projections are arranged so that they are denser toward the protruding tip side of the linear projections. In this case, it is possible to suitably prevent the balloon from slipping when the balloon is inflated. Furthermore, since the rough surface regions are arranged so that they are sparser toward the protruding base end side of the linear projections (the side opposite the protruding tip side), it is possible to reduce the sliding resistance when the balloon is introduced into the vessel compared to when the rough surface regions are densely arranged over the entire surface of the linear projections. This makes it possible to suitably prevent the balloon from slipping while further preventing a decrease in the balloon's passability.

[0019] A fifth disclosure provides a balloon catheter according to the first or second disclosure, wherein the roughened surface region has a surface roughness that increases toward the protruding tip of the linear protrusion.

[0020] According to the fifth disclosure, the surface roughness of the roughened surface region increases toward the protruding tip of the linear protrusion, thereby effectively preventing the balloon from slipping when inflated. Furthermore, the surface roughness of the roughened surface region decreases toward the protruding base of the linear protrusion, thereby reducing the sliding resistance when the balloon is introduced into the tube compared to when the surface roughness of the entire roughened surface region is increased. This effectively prevents the balloon from slipping while further preventing a decrease in the balloon's passability, as in the fourth disclosure.

[0021] The balloon catheter of the sixth disclosure is the balloon catheter of the first or second disclosure, wherein the balloon has a pair of tapered sections on either side of the straight tube section, the tapered sections having a diameter that narrows toward the side away from the straight tube section, and the surface of the tapered sections has a surface roughness that is greater than that of the surface of the straight tube section, and the surface roughness of the tapered sections is less than that of the roughened surface region.

[0022] When the tapered portion of the balloon dilates the lesion, the tapered portion contacts the lesion at an angle, and as a reaction, the tapered portion is pushed obliquely by the lesion, which may cause the balloon to slip in the axial direction. In this regard, in the sixth disclosure, the surface roughness of the tapered portion is greater than the surface roughness of the straight tube portion. In this case, the tapered portion's surface contacts the lesion, preventing the tapered portion from slipping in the axial direction, and ultimately preventing the balloon from slipping in the axial direction. Furthermore, because the surface roughness of the tapered portion's surface is smaller than the surface roughness of the roughened surface region of the linear protrusion, the above-mentioned effects can be achieved while preventing a decrease in passability when the balloon is introduced into the tube.

[0023] A manufacturing method for a balloon catheter of the seventh disclosure is a manufacturing method for manufacturing the balloon catheter of the first disclosure, comprising: a tubular parison that is the base of the balloon has protrusions that are the base of the linear protrusions on its outer surface; a mold used to manufacture the balloon has an internal space in which the balloon is formed, the internal space having a space portion that forms the straight tubular portion; an inner wall surface of the mold that forms the internal space has a groove portion for forming the linear protrusions in a wall portion that forms the space portion, the inner surface of the groove portion having a rough surface portion that is rougher than the wall surface portion; and an expansion step of expanding the parison in the internal space to tightly contact the outer surface of the parison with the inner wall surface and forcing the protrusions into the grooves to form the linear protrusions;

[0024] According to the seventh disclosure, when the parison is expanded in the internal space of the mold, the protruding portions of the parison are forced into grooves formed in the wall surface of the mold, forming linear protrusions. Furthermore, when the protruding portions of the parison are forced into the grooves and come into close contact with the roughened surface formed on the inner surface of the grooves, a roughened surface region is formed on the surface of the linear protrusions. In this case, because the roughened surface region can be formed when the parison is expanded, there is no need to perform a post-process, such as scraping the surface of the linear protrusions to form a roughened surface region, after expanding the parison to form a balloon with linear protrusions. This allows the balloon catheter of the first disclosure described above to be manufactured relatively easily.

[0025] The eighth disclosure relates to a method for manufacturing a balloon catheter according to the seventh disclosure, wherein the expansion step includes a first expansion step in which the inside of the parison is pressurized with a first pressure to expand the parison and cause the protrusion to enter the groove, and a second expansion step in which, after the first expansion step, the inside of the parison is pressurized with a second pressure higher than the first pressure to force the protrusion into the groove and cause it to adhere to the rough surface.

[0026] According to the eighth disclosure, during the expansion step, the parison is first expanded by applying a relatively low first pressure to the interior of the parison, causing the protruding portions of the parison to fit into the grooves (first expansion step). In this case, the parison can be expanded relatively slowly, making it possible for the protruding portions of the parison to fit into the grooves reliably. Thereafter, the parison is pressurized with a second pressure higher than the first pressure to force the protruding portions of the parison into the grooves and bring them into close contact with the roughened surface (second expansion step). In this case, the protruding portions can be firmly pressed into the grooves to make them fit closely with the roughened surface. Therefore, a roughened surface region can be suitably formed on the surface of the linear protrusions.

[0027] The ninth disclosure relates to the eighth disclosure in a method for manufacturing a balloon catheter, wherein in the first expansion step, the parison is heated to a first temperature, and in the second expansion step, the parison is heated to a second temperature higher than the first temperature.

[0028] According to the ninth disclosure, during the second expansion step, the parison is heated to a higher temperature (second temperature) than during the first expansion step. In this case, the protruding portions of the parison can be pressed into the grooves in a softened state, making it easier for the protruding portions to adhere to the roughened surface portion. This makes it possible to more effectively form a roughened surface region on the linear protruding portions.

[0029] A tenth disclosure provides a method for manufacturing a balloon catheter according to any one of the seventh to ninth disclosures, wherein the height of the protrusion is greater than the depth of the groove.

[0030] According to the tenth disclosure, the height of the protrusions of the parison is greater than the depth of the grooves. Therefore, when the protrusions are pressed into the grooves, they can be firmly pressed to the bottom of the grooves and adhere to the roughened surface. This ensures that the roughened surface area extends to the tip of the linear protrusions. This effectively prevents the balloon from slipping during inflation.

[0031] The eleventh disclosure relates to a method for manufacturing a balloon catheter according to any one of the seventh to ninth disclosures, wherein the groove has a valley-shaped cross section, the protrusion has a mountain-shaped cross section, the inner surface of the groove includes two side surfaces that form the valley shape, the surface of the protrusion includes two side surfaces that form the mountain shape, and the angle formed by the side surfaces of the protrusion is greater than the angle formed by the side surfaces of the groove.

[0032] According to the eleventh disclosure, the cross section of the protrusion of the parison is mountain-shaped, and the cross section of the groove is valley-shaped. The angle between the sides of the protrusion is larger than the angle between the sides of the groove. In this case, when the protrusion is pressed into the groove, the protrusion can be deformed to fit along the side surfaces of the groove, and can be firmly attached to the side surfaces (and thus the rough surface portions). Therefore, the above configuration can be said to be a preferable configuration for forming a rough surface region on a mountain-shaped linear protrusion.

[0033] The twelfth disclosure relates to a method for manufacturing a balloon catheter according to the eleventh disclosure, wherein the angle formed by the side of the groove in the open portion of the groove relative to the width direction of the groove is larger than that formed further back than the open portion of the groove.

[0034] In the above-mentioned eleventh disclosure, in which the cross section of the groove is valley-shaped and the cross section of the protrusion is mountain-shaped, it is anticipated that the protrusion may slip along the side surface of the groove after entering the groove. In such a case, there is a risk of problems such as an inability to properly form a roughened surface area on the side surface of the linear protrusion. Therefore, in the twelfth disclosure, in consideration of such problems, the angle that the side surface of the groove forms with respect to the width direction of the groove is made larger at the open portion of the groove than at the inner side of the groove than the open portion. In this case, it is possible to prevent the protrusion that has entered the groove from slipping along the side surface of the groove. Therefore, the above-mentioned problems caused by the slippage of the protrusion can be prevented.

[0035] The thirteenth disclosure relates to a method for manufacturing a balloon catheter according to any one of the seventh to ninth disclosures, wherein the width of the groove portion decreases toward the bottom of the groove portion, the inner surface of the groove portion includes two adjacent side surfaces interposed between the bottom portion, and in the expansion process, the protrusion portion is pushed into the groove portion so that the protrusion first abuts against each side surface of the groove portion and then abuts against the bottom portion.

[0036] According to the thirteenth disclosure, when the protrusion is pressed into the groove, the protrusion can be pressed to the bottom of the groove while being deformed so as to conform to each side surface of the groove. In this case, the protrusion can be suitably brought into close contact with the entire area of each side surface of the groove (and therefore the rough surface portion), and a rough surface region can be suitably formed on the linear protrusion. [Brief explanation of the drawings]

[0037] The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. [Figure 1] 1 is a schematic overall side view showing the configuration of a balloon catheter. [Figure 2] (a) is a side view showing the configuration of the balloon and its surroundings in an inflated state, (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). [Figure 3] FIG. 2 is a side view showing the balloon and its surrounding configuration in an inflated state, with the balloon and outer tube shown in longitudinal cross section. [Figure 4] FIG. 1(a) is a side view showing the configuration of the balloon and its surroundings in a contracted state, and FIG. 1(b) is a cross-sectional view taken along line BB in FIG. [Figure 5] 1A is a cross-sectional view showing the configuration of the mold, FIG. 1B is a cross-sectional view taken along line CC in FIG. 1A, and FIG. 1C is an enlarged cross-sectional view showing the groove in FIG. [Figure 6] FIG. [Figure 7]FIG. 2(a) is a cross-sectional view showing a state in which a parison is expanded in the internal space of a mold, and FIG. 2(b) is a cross-sectional view taken along line DD of FIG. [Figure 8] FIG. 10 is a cross-sectional view showing the flow when the protruding portion of the parison is pressed into the groove of the mold during the expansion process. [Figure 9] FIG. 10 is a side view showing the configuration of a balloon and its surroundings in another embodiment. [Figure 10] FIG. 10 is an enlarged side view showing a linear protrusion having a roughened surface region formed thereon according to another embodiment. [Figure 11] FIG. 10 is a cross-sectional view showing a groove portion of a mold according to another embodiment. [Figure 12] FIG. 10 is a side view showing the configuration of a balloon and its surroundings in another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0038] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present disclosure will now be described with reference to the accompanying drawings, in which: Figure 1 is a schematic overall side view showing the configuration of a balloon catheter;

[0039] As shown in FIG. 1, the balloon catheter 10 comprises a catheter body 11, a hub 12 attached to the base end (proximal end) of the catheter body 11, and a balloon 13 attached to the tip side (distal end) of the catheter body 11.

[0040] The catheter main body 11 comprises an outer tube 15 and an inner tube 16 inserted into the outer tube 15. The outer tube 15 is formed in a tubular shape from a resin material and has a lumen 15a (see FIG. 3) extending therein over the entire axial direction. The base end of the outer tube 15 is joined to the hub 12, and the tip end of the outer tube 15 is joined to the balloon 13. The lumen 15a of the outer tube 15 communicates with the interior of the hub 12 and the interior of the balloon 13. The lumen 15a of the outer tube 15 serves as a fluid lumen through which a compressed fluid flows when the balloon 13 is inflated or deflated.

[0041] The outer tube 15 may be formed by joining a plurality of tubes arranged in the axial direction together. In this case, the tube on the base end side of the plurality of tubes may be made of a metal material, and the tube on the tip end side may be made of a resin material.

[0042] The inner tube 16 is made of a resin material and has a tubular shape, and has a lumen 16a (see FIG. 3) extending throughout the axial direction. The base end of the inner tube 16 is joined to a midpoint in the axial direction of the outer tube 15. A portion of the distal end of the inner tube 16 extends further distally than the outer tube 15, and this extended portion is inserted into the balloon 13. The distal end of the inner tube 16 is joined to the distal end of the balloon 13.

[0043] The lumen 16a of the inner tube 16 serves as a guidewire lumen through which a guidewire G is inserted. A proximal opening 18 of the lumen 16a is located midway along the axial direction of the balloon catheter 10. This makes the balloon catheter 10 an RX-type catheter. The proximal opening 18 of the lumen 16a may also be located at the proximal end of the balloon catheter 10. In that case, the balloon catheter 10 would be an over-the-wire-type catheter.

[0044] Next, the configuration of the balloon 13 and its surroundings will be described with reference to Figures 2 to 4. Figure 2(a) is a side view showing the balloon 13 and its surroundings in an inflated state, (b) is a cross-sectional view taken along line AA in (a), and (c) is a cross-sectional view showing an enlarged linear protrusion 20 in (b). Figure 3 is a side view showing the balloon 13 and its surroundings in an inflated state, showing the balloon 13 and the outer tube 15 in longitudinal cross section. Figure 4(a) is a side view showing the balloon 13 and its surroundings in a deflated state, and (b) is a cross-sectional view taken along line BB in (a).

[0045] The balloon 13 is made of a thermoplastic resin material, such as polyamide elastomer. As shown in Figures 2(a) and 3, the balloon 13 is formed in a cylindrical (tubular) shape with a circular cross section as a whole. Specifically, the balloon 13 has a base-side leg portion 13a, a base-side tapered portion 13b, a straight pipe portion 13c, a tip-side tapered portion 13d, and a tip-side leg portion 13e, and these portions 13a to 13e are arranged in the above order from the base end to the tip end.

[0046] The proximal leg portion 13a is joined to the distal end of the outer tube 15. The proximal tapered portion 13b has a tapered shape, increasing in diameter from the distal end of the proximal leg portion 13a toward the distal end. The straight tube portion 13c extends from the distal end of the proximal tapered portion 13b toward the distal end with a constant diameter, and has a circular tubular (cylindrical) shape. The straight tube portion 13c is the portion whose diameter becomes largest when the balloon 13 is inflated. The distal tapered portion 13d has a tapered shape, decreasing in diameter from the distal end of the straight tube portion 13c toward the distal end. The distal leg portion 13e is joined to the distal end of the inner tube 16.

[0047] When compressed fluid is supplied to the interior of the balloon 13 through the lumen 15a of the outer tube 15, the balloon 13 enters an expanded state. On the other hand, when negative pressure is applied to the lumen 15a of the outer tube 15 and the compressed fluid is discharged from the interior of the balloon 13, the balloon 13 enters a deflated state. As shown in FIGS. 4( a) and 4(b), the balloon 13 has a plurality of (three in this embodiment) wing portions 21 formed in the deflated state. These wing portions 21 are spaced at predetermined intervals (more specifically, at equal intervals) around the circumference of the balloon 13. Each wing portion 21 is formed to extend in the axial direction across the tapered portions 13b, 13d and the straight portion 13c of the balloon 13. When the balloon 13 enters a deflated state, these wing portions 21 are folded along the outer periphery of the balloon 13 and wrapped around the inner tube 16.

[0048] A pair of contrast rings 19 are attached to the inner tube 16 on the inside of the balloon 13. The contrast rings 19 are intended to improve the visibility of the balloon 13 under X-ray projection and to facilitate the positioning of the balloon 13 at the target treatment site.

[0049] In this balloon catheter 10, a linear protrusion 20 is provided on the surface of the straight tube portion 13c of the balloon 13, extending linearly along the surface. The linear protrusion 20 is used to make an incision in the lesion when the balloon 13 is inflated to dilate the lesion. In this balloon catheter 10, the linear protrusion 20 makes an incision in the lesion, which facilitates dilation of the lesion by using the incision as a trigger. Therefore, this balloon catheter 10 is a balloon catheter with a scoring function.

[0050] The linear protrusions 20 protrude from the surface of the straight pipe portion 13c and extend along the surface in the axial direction of the balloon 13. Specifically, the linear protrusions 20 extend over the entire axial direction of the straight pipe portion 13c. A plurality of linear protrusions 20 are arranged at predetermined intervals (specifically, equal intervals) around the circumference of the balloon 13, and in this embodiment, three linear protrusions 20 are arranged. Furthermore, each linear protrusion 20 is integrally formed with the balloon 13.

[0051] Each linear protrusion 20 has a cross section (more specifically, a cross section perpendicular to the longitudinal direction of the linear protrusion 20) that has a mountain-like shape that protrudes radially outward from the balloon 13, more specifically, a triangular shape. The end of the linear protrusion 20 on the protruding tip side is an apex 20a. The linear protrusion 20 has two side surfaces 20b adjacent to each other with the apex 20a interposed therebetween.

[0052] A rough surface region 25 having a surface roughness greater than that of the surface of the straight pipe 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. In FIG. 2(a), the rough surface region 25 is indicated by dot hatching. The rough surface region 25 is formed over the entire area of each side surface 20b of the linear protrusion 20 (i.e., the entire surface of the linear protrusion 20), and the surface roughness is constant over the entire rough surface region 25. The rough surface regions 25 of each linear protrusion 20 all have the same surface roughness. The surface roughness of the surface of the balloon 13 is constant over the entire surface of the balloon 13.

[0053] In addition, in this specification, "surface roughness" means the calculated average roughness Ra specified in JIS B0601: 2001. The calculated average roughness Ra is measured in accordance with JIS B0633: 2001, and a measuring instrument specified in JIS B0651: 2001 is used for the measurement.

[0054] Next, a method for manufacturing the above-mentioned balloon 13 will be described. The balloon 13 is manufactured using a mold 30. Therefore, the configuration of the mold 30 will be first described below with reference to Fig. 5. In Fig. 5, (a) is a cross-sectional view showing the configuration of the mold 30, (b) is a cross-sectional view taken along line CC in (a), and (c) is an enlarged cross-sectional view showing the groove portion 35 in (b).

[0055] As shown in Fig. 5(a), the mold 30 is formed in a rectangular parallelepiped shape and has an internal space 31 therein 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. Therefore, as shown in Fig. 5(b), the cross-sectional shape of the internal space 31 (more specifically, the shape of the cross section perpendicular to the longitudinal direction of the internal space 31) is circular throughout the entire longitudinal area.

[0056] The internal space 31 has a space 31a that forms the proximal leg portion 13a of the balloon 13, a space 31b that forms the proximal tapered portion 13b, a space 31c that forms the straight tube portion 13c, a space 31d that forms the distal tapered portion 13d, and a space 31e that forms the distal leg portion 13e. Each of these spaces 31a to 31e has a shape that corresponds to each of the portions 13a to 13e of the balloon 13.

[0057] The mold 30 has an inner wall surface 32 that forms an internal space 31. The inner wall surface 32 is a surface that surrounds the internal space 31. The surface roughness of the inner wall surface 32 is constant over the entire area of the inner wall surface 32. Of the inner wall surface 32, an inner wall surface 32a (corresponding to a wall surface portion) that forms a space portion 31c (corresponding to a "space portion" in the claims) for the straight pipe portion 13c has a plurality of (specifically, three) groove portions 35 formed therein. These groove portions 35 extend in the longitudinal direction of the internal space 31 and are arranged at equal intervals in the circumferential direction of the inner wall surface 32.

[0058] As shown in FIG. 5(c), each groove 35 has a cross section (more specifically, a cross section perpendicular to the longitudinal direction of the groove 35) that is valley-shaped, in other words, V-shaped. The cross section of the groove 35 corresponds to the cross section (mountain shape) of the linear protrusion 20. The groove 35 has two side surfaces 35b (corresponding to the inner surfaces of the groove 35) that form the valley shape. These side surfaces 35b are adjacent to each other with the bottom 35a (valley bottom) of the groove 35 interposed therebetween. In this case, the width of the groove 35 decreases toward the bottom 35a of the groove 35.

[0059] 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. In FIG. 5(a), the rough surface portion 36 is indicated by dot hatching.

[0060] Next, a manufacturing method for manufacturing the balloon 13 using the above-described mold 30 will be described with reference to Figures 6 and 7. Figure 6 is a perspective view showing a parison 37. Figure 7(a) is a cross-sectional view showing the parison 37 inflated in the internal space 31 of the mold 30, and Figure 7(b) is a cross-sectional view taken along line DD in Figure 7(a).

[0061] The manufacturing process for the balloon 13 begins with a preparation step of preparing a mold 30 and a parison 37, which is the base of the balloon 13. As shown in FIG. 6, the parison 37 is formed into a cylindrical shape from a resin material by, for example, extrusion molding. The parison 37 has multiple (specifically, three) protrusions 38 protruding from its outer periphery. These protrusions 38 are the bases of the linear protrusions 20 of the balloon 13. The cross-section of each protrusion 38 (specifically, a cross-section perpendicular to the longitudinal direction of the parison 37) has a mountain-like shape that protrudes radially outward from the parison 37, specifically a pentagonal shape (i.e., a home plate shape). Each protrusion 38 extends in the longitudinal direction of the parison 37, specifically across the entire longitudinal length of the parison 37. Each protrusion 38 has two side surfaces 38b (corresponding to the surfaces of the protrusions 38) that form the mountain-like shape. These side surfaces 38b are adjacent to each other via the tops 38a of the protrusions 38.

[0062] Next, an arrangement step is performed in which the parison 37 is arranged in the internal space 31 of the mold 30. In this step, the parison 37 is arranged in the internal space 31 with the longitudinal direction of the parison 37 facing the longitudinal direction of the internal space 31. As a result, the parison 37 is arranged so as to straddle each of the space portions 31a to 31e of the internal space 31. Thereafter, a stretching step is performed in which the parison 37 is stretched in the longitudinal direction.

[0063] 7(a) and 7(b), an expansion step is performed in which the parison 37 is expanded in the internal space 31 of the mold 30, thereby bringing the outer circumferential surface of the parison 37 into close contact with the inner wall surface 32. In this step, a pressurized fluid such as nitrogen is introduced into the interior of the parison 37 to pressurize the interior of the parison 37, thereby expanding the parison 37. This forms an expanded parison 37A including the portions 13a to 13d of the balloon 13.

[0064] In the expansion process, a pressurized fluid is introduced into the parison 37 using a fluid supply device (not shown). The fluid supply device is capable of adjusting the pressurized pressure inside the parison 37 by adjusting the amount of 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 is capable of adjusting the heating temperature of the parison 37.

[0065] 7(b), in the expansion process, the parison 37 is expanded, forcing each protrusion 38 of the parison 37 into each groove 35 of the mold 30, thereby shaping each protrusion 38 into the shape of the linear protrusion 20 of the balloon 13. As a result, each linear protrusion 20 is formed in the straight tube portion 13c of the balloon 13. In the expansion process, the protrusion 38 of the parison 37 is forced into the groove 35, forcing the protrusion 38 into close contact with each side surface 35b (each rough surface portion 36) of the groove 35, thereby forming a rough surface region 25 on each side surface 20b of the linear protrusion 20.

[0066] Next, the expansion step will be described in more detail with reference to Fig. 8. Fig. 8 is a cross-sectional view showing the flow when the protruding portion 38 of the parison 37 is pressed into the groove portion 35 of the mold 30 during the expansion step.

[0067] First, the dimensional relationship between the protrusion 38 of the parison 37 and the groove 35 of the mold 30 will be described with reference to Figure 8(a). As shown in Figure 8(a), the width W1 (maximum width) of the protrusion 38 is smaller than the width W2 (maximum width) of the groove 35. Furthermore, the height H1 of the protrusion 38 is greater than the depth H2 of the groove 35. Note that the height H1 of the protrusion 38 is the height from the outer peripheral surface of the parison 37. Furthermore, the angle a formed by each side surface 38b of the protrusion 38 is greater than the angle b formed by each side surface 35b of the groove 35.

[0068] Next, the flow of the expansion process will be described. First, as shown in FIG. 8(b), a first expansion process is performed in which the parison 37 is expanded to fit each of the protrusions 38 of the parison 37 into the grooves 35. In the first expansion process, the parison 37 is expanded by applying a relatively low first pressure P1 to the interior of the parison 37. In this case, the parison 37 can be expanded relatively slowly, so that the protrusions 38 can be reliably fitted into the grooves 35. Furthermore, the width W1 of the protrusions 38 is smaller than the width W2 of the grooves 35, so that the protrusions 38 can be easily fitted into the grooves 35. Furthermore, in the first expansion process, the parison 37 is expanded while being heated at a relatively low first temperature T1.

[0069] In the first expansion step, the pressure inside the parison 37 (i.e., the first pressure P1) is increased relatively slowly, and the heating temperature of the parison 37 (i.e., the first temperature T1) is also increased relatively slowly. However, in the first expansion step, the pressure inside the parison 37 may be kept constant, and the heating temperature of the parison 37 may be kept constant.

[0070] Next, as shown in FIG. 8( c), a second expansion step is performed in which the parison 37 is further expanded to press the protrusions 38 into the grooves 35, thereby closely adhering the protrusions 38 to the side surfaces 35b (i.e., the rough surface portions 36) of the grooves 35. This forms a rough surface region 25 on each side surface 20b of the linear protrusion 20. In the second expansion step, the parison 37 is expanded by applying a second pressure P2 higher than the first pressure P1 to the interior of the parison 37. In this case, the protrusions 38 are strongly pressed into the grooves 35, allowing them to closely adher to the side surfaces 35b. This allows the rough surface region 25 to be suitably formed on the linear protrusion 20.

[0071] In the second expansion step, the parison 37 is expanded while being heated to a second temperature T2 higher than the first temperature T1. In this case, the protrusions 38 of the parison 37 can be pressed into the grooves 35 in a softened state, which makes it easier for the protrusions 38 to be brought into close contact with the side surfaces 35b (rough surface portions 36) of the grooves 35. Therefore, in this respect as well, the rough surface regions 25 can be suitably formed on the linear protrusions 20.

[0072] In the second expansion step, the pressure inside the parison 37 (i.e., the second pressure P2) is increased more quickly than in the first expansion step, and the heating temperature of the parison 37 (i.e., the second temperature T2) is increased more quickly than in the first expansion step. However, in the second expansion step, the pressure inside the parison 37 may be kept constant, and the heating temperature of the parison 37 may be kept constant.

[0073] Furthermore, since the angle a formed by each side surface 38b of the protrusion 38 is larger than the angle b formed by each side surface 35b of the groove 35, when the protrusion 38 is pressed into the groove 35, the protrusion 38 can be deformed to fit along each side surface 35b of the groove 35 and can be firmly attached to each side surface 35b (i.e., the rough surface portion 36). Therefore, the rough surface region 25 can be suitably formed on the mountain-shaped linear protrusion 20.

[0074] Furthermore, because 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 first abuts against the side surfaces 35b of the groove 35 (see FIG. 8(b)), and then abuts against the bottom 35a of the groove 35 (see FIG. 8(c)). In this case, the protrusion 38 can be pressed down to the bottom 35a of the groove 35 while being deformed so as to conform to the side surfaces 35b of the groove 35. Therefore, the protrusion 38 can be suitably brought into close contact with the entire side surfaces 35b of the groove 35 (and thus the rough surface portion 36), and the rough surface region 25 can be suitably formed on the linear protrusion 20.

[0075] During the expansion process, the portion of the protrusion 38 of the parison 37 that does not enter the groove 35 is pressed against the inner wall surface 32 and crushed. Therefore, the linear protrusion 20 is not formed in each of the portions 13a, 13b, 13d, and 13e other than the straight pipe portion 13c.

[0076] After the expansion step, a cutting step is carried out in which the excess portions on both ends of the parison expandable body 37A are cut off, thereby forming the balloon 13, and the manufacture of the balloon 13 is completed.

[0077] Thereafter, subsequent steps include joining the balloon 13 to the catheter body 11, joining the hub 12 to the catheter body 11, etc. This completes the series of manufacturing steps.

[0078] Next, a method of using the balloon catheter 10 will be described. Here, a procedure for dilating a lesion occurring in a blood vessel using the balloon catheter 10 will be described.

[0079] First, a guiding catheter is inserted into a sheath introducer inserted into a blood vessel, and the tip opening of the guiding catheter is introduced to the coronary artery ostium. Next, a guidewire G is inserted into the guiding catheter, and the inserted guidewire G is introduced from the coronary artery ostium to the peripheral area via the lesion.

[0080] Next, the balloon catheter 10 is introduced into the guiding catheter along the guidewire G. After introduction, the balloon 13 is introduced (positioned) toward the lesion while being pushed and pulled. During this introduction, the balloon 13 is kept in a deflated state. When the balloon 13 is in a deflated state, the linear projections 20 are covered from the outer periphery by the wing portions 21 (see FIG. 4(b)). Therefore, when the balloon 13 is introduced, the roughened surface regions 25 formed on the linear projections 20 can be prevented from sliding against the vessel wall. This prevents a decrease in the penetrability of the balloon 13, even in a configuration in which the roughened surface regions 25 are formed on the linear projections 20.

[0081] When the balloon 13 reaches the lesion, it is inflated. This causes the linear projections 20 to press against the lesion, creating incisions (cracks) in the lesion. This allows the lesion to be broken or otherwise expanded outward, using the incisions as a trigger. Furthermore, at this time, the roughened surface regions 25 of the linear projections 20 come into contact with the lesion, preventing the balloon 13 from slipping. This allows the lesion to be expanded appropriately at the desired location.

[0082] After the balloon 13 has completed dilating the lesion, the balloon 13 is deflated. Then, in this deflated state, the balloon catheter 10 is pulled out from the body, thereby completing the series of operations.

[0083] As described above, the balloon catheter 10 is primarily used to pass through blood vessels and treat blood vessels such as the coronary arteries, femoral arteries, and pulmonary arteries. However, it can also be used in other "tubes" within the body, such as the urinary tract and digestive tract, as well as in "body cavities."

[0084] According to the configuration of this embodiment described above in detail, the following excellent effects can be obtained.

[0085] As described above, by bringing the roughened surface region 25 of the linear protrusions 20 into contact with the lesion when the balloon 13 is inflated, it is possible to prevent the balloon 13 from slipping. In addition, the surface roughness of the straight tube portion 13c of the balloon 13 is smaller than that of the roughened surface region 25 of the linear protrusions 20. Since the surface area of the straight tube portion 13c is significantly larger than that of the linear protrusions 20, in this case, the reduced surface roughness of the surface of the straight tube portion 13c can reduce the sliding resistance when the balloon 13 is introduced into a blood vessel. This makes it possible to prevent the balloon 13 from slipping when inflated, while also preventing a decrease in the passability of the balloon 13 within the blood vessel.

[0086] When the parison 37 is expanded and the protrusions 38 of the parison 37 are forced into the grooves 35 of the mold 30, the protrusions 38 are brought into close contact with the rough surface portions 36 formed in the grooves 35, thereby forming the rough surface regions 25 on the side surfaces 20b of the linear protrusions 20. In this case, after the parison 37 is expanded to form the balloon 13 having the linear protrusions 20, there is no need to perform a post-process such as scraping the side surfaces 20b of the linear protrusions 20 to form the rough surface regions 25. This makes it relatively easy to manufacture the above-mentioned balloon 13 having the rough surface regions 25 formed on the linear protrusions 20.

[0087] The present disclosure is not limited to the above-described embodiment, and may be implemented, for example, as follows.

[0088] (1) In the above embodiment, the roughened 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 roughened surface region may be formed on only a portion of the surface of the linear protrusion 20. A specific example is shown in FIG. 9. In the example shown in FIG. 9, each linear protrusion 40 has a cutout 41. A plurality of cutouts 41 (specifically, two cutouts) 41 are provided on each linear protrusion 40. Each cutout 41 is arranged in the linear protrusion 40 at a position that divides the linear protrusion 40 into approximately equal parts (specifically, three equal parts).

[0089] The linear protrusion 40 is divided into multiple regions 40a to 40c by each notch 41. Each of these regions 40a to 40c includes a base-end region 40a located on the base end side, a tip-end region 40b located on the tip end side, and an intermediate region 40c located between the base-end region 40a and the tip-end region 40b. Of these regions 40a to 40c, a roughened surface region 45 having a surface roughness greater than that of the surface of the straight pipe portion 13c is formed on the surface of the intermediate region 40c. On the other hand, the roughened surface region 45 is not formed on the surface of the base-end region 40a or the surface of the tip-end region 40b. Therefore, in this example, the roughened surface region 45 is formed only in the intermediate region 40c of the linear protrusion 40.

[0090] With the above configuration, when the balloon 13 is introduced into a blood vessel in a deflated state, even if the distal region 40b or the proximal region 40a of the linear protrusion 40 protrudes from the blades 21 and slides against the vessel wall, an increase in sliding resistance can be suppressed. This further suppresses a decrease in the penetrability of the balloon 13 through the blood vessel.

[0091] (2) In the configuration of the above embodiment, the surface roughness of the rough surface region 25 may be decreased toward the longitudinal ends of the linear protrusion 20. For example, the surface roughness of the rough surface region 25 is greatest at the longitudinal center of the linear protrusion 20. Then, the surface roughness of the rough surface region 25 is decreased from the longitudinal center toward one end of the linear protrusion 20, and is decreased from the longitudinal center toward the other end of the linear protrusion 20. With this configuration, the same effect as in (1) above can be obtained.

[0092] (3) A plurality of rough surface regions may be formed on the surface of the linear protrusion. A specific example is shown in FIG. 10 . FIG. 10 is an enlarged side view of a linear protrusion 50 on which a plurality of rough surface regions 53 are formed. In the example shown in FIG. 10 , a plurality of rough surface regions 53 are formed on each side surface 50 a of the linear protrusion 50. Each rough surface region 53 extends in the longitudinal direction of the linear protrusion 50, and more specifically, extends over the entire longitudinal direction of the linear protrusion 50. On the side surface 50 a of the linear protrusion 50, the rough surface regions 53 are arranged at predetermined intervals. In this case, the rough surface regions 53 are arranged so that the intervals between adjacent rough surface regions 53 become smaller toward the protruding tip of the linear protrusion 50. Therefore, the rough surface regions 53 are arranged so that they become denser toward the protruding tip of the linear protrusion 50.

[0093] When the balloon 13 is inflated and the linear protrusions 50 are applied to the lesion, the contact occurs primarily at the protruding tip side of the linear protrusions 50. In this regard, according to the above configuration, the rough surface regions 53 are arranged so that they become denser toward the protruding tip side of the linear protrusions 50, and therefore, slippage of the balloon 13 during inflation can be suitably suppressed.

[0094] Furthermore, since the rough surface regions 53 are arranged so that they become less dense toward the protrusion base end of the linear protrusion 50 (the side opposite the protrusion tip end), the sliding resistance when the balloon 13 is introduced into the blood vessel can be reduced compared to when the rough surface regions 53 are densely arranged over the entire area of each side surface 50a of the linear protrusion 50. This makes it possible to further prevent the balloon 13 from slipping while further preventing a decrease in the passability of the balloon 13.

[0095] (4) In the configuration of the above embodiment, the rough surface region 25 may be formed so that the surface roughness increases toward the protruding tip of the linear protrusion 20. In this case, slippage of the balloon 13 during inflation can be suitably prevented. Furthermore, with this configuration, the surface roughness of the rough surface region 25 decreases toward the protruding base end of the linear protrusion 20. Therefore, compared to when the surface roughness of the entire rough surface region 25 is increased, the sliding resistance when the balloon 13 is introduced into a blood vessel can be reduced. As a result, similar to the configuration of (3) above, slippage of the balloon 13 can be suitably prevented while further preventing a decrease in the passability of the balloon 13.

[0096] (5) The dimensional relationship between the groove 35 of the mold 30 and the protruding portion 38 of the parison 37 is not necessarily limited to that in the above embodiment. For example, the height H1 of the protruding portion 38 may be smaller than the depth H2 of the groove 35 or may be the same as the depth H2 of the groove 35. In this case, the entire protruding portion 38 can be reliably inserted into the groove 35. Furthermore, the angle a formed by each side surface 38b of the protruding portion 38 may be smaller than the angle b formed by each side surface 35b of the groove 35. In this case, the protruding portion 38 of the parison 37 can be more easily inserted into the groove 35.

[0097] (6) The cross-sectional shape of the groove of the mold 30 may be changed as shown in FIG. 11. In the example shown in FIG. 11, similar to the above embodiment, the cross-sectional shape of the groove 55 is a valley shape. Therefore, the groove 55 has two side surfaces 56 that form the valley shape. The angle that these side surfaces 56 form with respect to the width direction of the groove 55 changes midway. More specifically, the angle changes between the side surface portion 56a at the open portion 55a of the groove 55 and the side surface portion 56b that is located deeper than the open portion 55a. Specifically, the angle c that the side surface portion 56a forms with respect to the width direction of the groove 55 is larger than the angle d that the side surface portion 56b forms with respect to the width direction of the groove 55. The angle c is, for example, 90°.

[0098] According to the above configuration, during the expansion step, the protrusions 38 of the parison 37 that have entered the grooves 55 can be prevented from shifting along the side surfaces 56 of the grooves 55. This prevents the protrusions 38 from shifting from the grooves 55, preventing problems such as the roughened surface regions 25 from being properly formed on the side surfaces 20b of the linear protrusions 20.

[0099] (7) When the tapered portions 13b and 13d of the balloon 13 are used to dilate the lesion, the tapered portions 13b and 13d contact the lesion at an angle. As a reaction to this, the tapered portions 13b and 13d are pushed obliquely by the lesion, which may cause the balloon 13 to slip in the axial direction. In consideration of this, as shown in FIG. 12, the surface roughness of the tapered portions 13b and 13d of the balloon 13 may be made greater than the surface roughness of the straight portion 13c. In this case, the tapered portions 13b and 13d contact the lesion, thereby preventing the tapered portions 13b and 13d from slipping in the axial direction, and thus preventing the balloon 13 from slipping in the axial direction. In FIG. 12, the surfaces of the tapered portions 13b and 13d are indicated by dotted hatching.

[0100] 12, the surface roughness of the surfaces of the tapered portions 13b and 13d is smaller than the surface roughness of the roughened surface region 25 of the linear protrusion 20. This makes it possible to obtain the above-mentioned effects while suppressing a decrease in the penetrability when introducing the balloon 13 into a blood vessel. Note that the surface roughness of only one of the tapered portions 13b and 13d may be made larger.

[0101] (8) In the above embodiment, the straight tube portion 13c of the balloon 13 has linear protrusions 20 (first linear protrusions) protruding from its surface. In addition, the distal tapered portion 13d of the balloon 13 may have linear protrusions (second linear protrusions) protruding from its surface. In this case, the surface of the second linear protrusion may have a roughened surface region with a rougher surface than the surface of the straight tube portion 13c. This can further prevent the balloon 13 from slipping when inflated.

[0102] Similarly, a linear protrusion (third linear protrusion) protruding from the surface of the base end tapered portion 13b of the balloon 13 may be provided, and a roughened surface area having a greater surface roughness than the surface of the straight tube portion 13c may be formed on the surface of the third linear protrusion.

[0103] (9) In the above embodiment, the roughened surface regions 25 are formed on each side surface 20b of the linear protrusions 20 during the expansion step of expanding the parison 37. However, the method of forming the roughened surface regions 25 is not necessarily limited to this. For example, the roughened surface regions 25 may be formed by, for example, scraping the side surfaces 20b of the linear protrusions 20 after forming the balloon 13 having the linear protrusions 20.

[0104] Although the present disclosure has been described with reference to the embodiments, it is understood that the present disclosure is not limited to the embodiments or structures. The present disclosure also encompasses various modifications and modifications within the scope of equivalents. In addition, various combinations and forms, as well as other combinations and forms including only one element, more than one element, or less than one element, are also within the scope and spirit of the present disclosure. [Explanation of symbols]

[0105] 10...balloon catheter, 13...balloon, 13c...straight tube portion, 20...linear protrusion portion, 25...roughened surface area, 30...mold, 31...internal space, 35...groove portion, 36...roughened surface portion, 37...parison, 38...protrusion portion.

Claims

1. a balloon that can be inflated and deflated; the balloon has a cylindrical straight tube portion whose diameter becomes largest when inflated, a balloon catheter, wherein the straight tube portion is provided with a linear protrusion portion that protrudes from a surface of the straight tube portion and extends linearly along the surface, a roughened surface region having a surface roughness greater than that of the surface of the straight pipe portion is formed on the surface of the linear protrusion; the balloon has wings formed in its deflated state and folded around the circumference of the balloon; the linear protrusion extends in the axial direction of the balloon, and is covered from the outer periphery by the wing portion when the balloon is in a deflated state; A balloon catheter, wherein the roughened surface region is formed only in a longitudinally intermediate portion of the linear protrusion, or the surface roughness of the linear protrusion decreases toward the longitudinal end portions.

2. a balloon that can be inflated and deflated; the balloon has a cylindrical straight tube portion whose diameter becomes largest when inflated, a balloon catheter, wherein the straight tube portion is provided with a linear protrusion portion that protrudes from a surface of the straight tube portion and extends linearly along the surface, a roughened surface region having a surface roughness greater than that of the surface of the straight pipe portion is formed on the surface of the linear protrusion; a plurality of the roughened surface regions are formed on the surface of the linear protrusion; A balloon catheter, wherein the plurality of rough surface regions are arranged so that they become denser toward the protruding tip of the linear protrusion.

3. a balloon that can be inflated and deflated; the balloon has a cylindrical straight tube portion whose diameter becomes largest when inflated, a balloon catheter, wherein the straight tube portion is provided with a linear protrusion portion that protrudes from a surface of the straight tube portion and extends linearly along the surface, a roughened surface region having a surface roughness greater than that of the surface of the straight pipe portion is formed on the surface of the linear protrusion; The roughened surface region has a surface roughness that increases toward the protruding tip of the linear protrusion.

4. a balloon that can be inflated and deflated; the balloon has a cylindrical straight tube portion whose diameter becomes largest when inflated, a balloon catheter, wherein the straight tube portion is provided with a linear protrusion portion that protrudes from a surface of the straight tube portion and extends linearly along the surface, a roughened surface region having a surface roughness greater than that of the surface of the straight pipe portion is formed on the surface of the linear protrusion; the balloon has a pair of tapered portions provided on both sides of the straight pipe portion and tapered in diameter toward the side away from the straight pipe portion, the surface of the tapered portion has a surface roughness greater than that of the straight pipe portion; A balloon catheter, wherein the surface roughness of the tapered portion is smaller than the surface roughness of the roughened region.

5. the balloon has wings formed in its deflated state and folded around the circumference of the balloon; 5. The balloon catheter according to claim 2, wherein the linear protrusion extends in the axial direction of the balloon and is covered from the outer periphery by the wing portion when the balloon is in a deflated state.

6. A method for manufacturing a balloon catheter having an inflatable and deflatable balloon, comprising: the balloon has a cylindrical straight tube portion whose diameter becomes largest when inflated, The straight pipe portion is provided with a linear protrusion that protrudes from a surface of the straight pipe portion and extends linearly along the surface, a roughened surface region having a surface roughness greater than that of the surface of the straight pipe portion is formed on the surface of the linear protrusion; a tubular parison that is the base of the balloon has protrusions on its outer circumferential surface that are the base of the linear protrusions; a mold used to manufacture the balloon has an internal space for forming the balloon; the internal space has a space portion that forms the straight pipe portion, a wall surface portion that forms the space portion among inner wall surfaces that form the internal space in the mold is provided with a groove portion for forming the linear protrusion portion; 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, an expansion step of expanding the parison in the internal space to bring the outer peripheral surface of the parison into close contact with the inner wall surface and to push the protrusion into the groove to form the linear protrusion, In the expanding step, the protrusion is pushed into the groove and brought into close contact with the rough surface portion, thereby forming the rough surface region on the surface of the linear protrusion, The expansion step includes: a first expansion step of expanding the parison by applying a first pressure to the inside of the parison, thereby causing the protrusion to enter the groove; a second expansion step in which, after the first expansion step, the inside of the parison is pressurized with a second pressure higher than the first pressure, thereby forcing the protrusion into the groove and bringing it into close contact with the rough surface portion.

7. In the first expansion step, the parison is heated to a first temperature; 7. The method for manufacturing a balloon catheter according to claim 6, wherein the parison is heated to a second temperature higher than the first temperature in the second expansion step.

8. The method for manufacturing a balloon catheter according to claim 6 or 7, wherein the height of the protrusion is greater than the depth of the groove.

9. The groove portion has a valley-shaped cross section, The protrusion has a mountain-shaped cross section, the inner surface of the groove portion includes two side surfaces that form the valley shape; the surface of the protrusion includes two side surfaces that form the mountain shape; The method for manufacturing a balloon catheter according to claim 6 or 7, wherein an angle formed by each side surface of the protrusion is larger than an angle formed by each side surface of the groove.

10. 10. The method for manufacturing a balloon catheter according to claim 9, wherein the angle formed by the side surface of the groove with respect to the width direction of the groove is larger at the open portion of the groove than at a portion of the groove deeper than the open portion.

11. The width of the groove decreases toward the bottom of the groove, the inner surface of the groove includes two side surfaces adjacent to each other with the bottom portion interposed therebetween, 8. The method for manufacturing a balloon catheter according to claim 6, wherein in the expanding step, the protrusions are pushed into the grooves so that the protrusions first abut against the side surfaces of the grooves and then abut against the bottom.

Images