Balloon catheter and method of manufacturing the same

Abstract

The balloon 13 of the balloon catheter 10 has a proximal side leg portion 13a, a proximal side taper portion 13b, a straight tube portion 13c, a distal side taper portion 13d, and a distal side leg portion 13e. A first region 21 and a second region 22 having greater surface roughness than the first region 21 are formed on the outer surface of the balloon 13. The first region 21 is formed on the outer surface of the straight tube portion 13c, and the second region 22 is formed on the outer surfaces of each of the proximal side leg portion 13a, the proximal side taper portion 13b, the distal side taper portion 13d, and the distal side leg portion 13e.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Application No. 2022-192304, 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 is equipped with an inflatable and deflated balloon at its tip (see, for example, Patent Document 1). With a balloon catheter, the balloon is introduced in a deflated state to a site narrowed or blocked by a lesion or the like that has occurred in a blood vessel, and then the balloon is inflated to expand the site. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2020 / 255923 Summary of the Invention [Problem to be solved by the invention]

[0005] 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.

[0006] To prevent the balloon from slipping during inflation, it is possible to increase the surface roughness of the balloon's outer surface. For example, it is possible to increase the surface roughness of the balloon's outer surface along the entire axial direction. However, this configuration increases the sliding resistance when the balloon is introduced into a vessel, etc., which may reduce the balloon's ability to pass through the vessel.

[0007] 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]

[0008] In order to solve the above problem, the balloon catheter of the first disclosure is a balloon catheter equipped with an inflatable and deflatable balloon, and the outer surface of the balloon is formed with a first region and a second region that is located in a part of the axial direction of the balloon and has a surface roughness greater than that of the first region.

[0009] According to the first disclosure, the outer surface of the balloon is formed with a first region and a second region having a surface roughness greater than that of the first region. In this case, when the balloon is inflated, the second region abuts against the target to be dilated, such as a lesion, thereby preventing the balloon from slipping. Furthermore, the second region is only provided on a portion of the balloon in the axial direction, and the first region with a lower surface roughness is formed in the rest of the balloon. In this case, compared to when the second region is provided over the entire axial area of ​​the balloon, sliding resistance when the balloon is introduced into a vessel such as a blood vessel can be reduced. This prevents a decrease in the balloon's passability through the vessel and prevents the balloon from slipping when inflated.

[0010] The balloon catheter of the second disclosure is the same as that of the first disclosure, wherein the balloon has a straight tube section that has the largest diameter when inflated, and a pair of tapered sections that are located on both sides of the straight tube section in the axial direction and that decrease in diameter toward the side away from the straight tube section, and the second region is formed on the outer surface of the tapered sections.

[0011] When the tapered portion of the balloon is used to expand 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 second disclosure, a second region with high surface roughness is formed on the outer surface of the tapered portion. In this case, the second region of the tapered portion contacts the lesion when the balloon is inflated, thereby preventing the tapered portion from slipping in the axial direction, and ultimately preventing the balloon from slipping in the axial direction.

[0012] The balloon catheter of the third disclosure is the second disclosure, wherein the second region is formed on the outer surface of the tapered portion on the distal end side of the pair of tapered portions.

[0013] However, when a lesion in a vessel or other lumen is large, the inside of the lesion is narrowed, making it difficult to insert the straight portion of the balloon into the lesion. Therefore, in such cases, it is possible to first insert the tapered portion of the balloon, which has a relatively small diameter at the tip, into the lesion and then inflate the balloon in this state. In this case, the tapered portion at the tip dilates the lesion.

[0014] However, when dilating the lesion in this manner, the tapered portion on the distal end side may be pushed from the lesion toward the base end (proximal side), causing the tapered portion on the distal end side to slip toward the base end. In light of this, the third disclosure provides a second region on the outer surface of the tapered portion on the distal end side. This prevents the tapered portion on the distal end side from slipping toward the base end when dilating the lesion as described above, thereby preventing the balloon from slipping toward the base end.

[0015] The balloon catheter of the fourth disclosure is the same as that of the third disclosure, and includes a catheter body with the balloon provided on the tip side, the balloon being provided on the opposite side of the tapered portion on the tip side from the straight tube portion and having a tip leg portion joined to the catheter body, and the second region being formed on the outer surface of the tip leg portion.

[0016] When the inside of the lesion is narrow, it is possible to introduce the distal leg section together with the distal tapered section into the lesion and inflate the balloon in this introduced state. In this regard, in the fourth disclosure, in addition to the distal tapered section, a second region is also formed on the outer surface of the distal leg section. This further prevents the balloon from slipping toward the base end when inflating the balloon as described above.

[0017] The balloon catheter of a fifth disclosure is any one of the second to fourth disclosures, wherein the first region is formed on the outer surface of the straight tube portion.

[0018] Because the straight tube section is the part of the balloon with the largest diameter, it is prone to sliding against the tube wall when the balloon is introduced into the tube. In this regard, in the fifth disclosure, the first region with low surface roughness is formed on the outer surface of the straight tube section, which can suitably reduce sliding resistance when the balloon is introduced into the tube. This can suitably reduce the passability of the balloon.

[0019] The balloon catheter of a sixth disclosure is the fifth disclosure, wherein the second region of the tapered portion has a surface roughness that decreases toward the straight tube portion.

[0020] In the tapered section, the diameter of the portion closer to the straight pipe section is relatively large. Therefore, when the balloon is introduced into the tube, it is thought that the portion of the tapered section closer to the straight pipe section will easily slide against the tube wall. In view of this, in the sixth disclosure, the surface roughness of the second region of the tapered section is made to decrease as it approaches the straight pipe section. In this case, when the balloon is introduced into the tube, the sliding resistance of the portion of the tapered section closer to the straight pipe section can be reduced. Therefore, the sliding resistance when the balloon is introduced into the tube can be further reduced.

[0021] The balloon catheter of the seventh disclosure is the same as that of the second disclosure, and includes a catheter body with the balloon provided at its tip end, the balloon being provided on the opposite side of the straight tube section across the tapered section in which the second region is formed, and having a leg section joined to the catheter body, with the second region formed on the outer surface of the leg section.

[0022] When the inside of the lesion is narrow, it is considered that the leg section will be introduced into the inside of the lesion together with the tapered section. In this regard, in the seventh disclosure, in addition to the outer surface of the tapered section, a second region is formed on the outer surface of the leg section. This further prevents the balloon from slipping when inflated.

[0023] The balloon catheter of an eighth disclosure is any one of the first to fourth disclosures, wherein the second region is provided over the entire circumferential area of ​​the balloon.

[0024] According to the eighth disclosure, since the second region is provided over the entire circumferential area of ​​the balloon, the second region can be reliably brought into contact with the target to be dilated, such as a lesion, when the balloon is inflated, thereby reliably preventing the balloon from slipping when inflated.

[0025] The balloon catheter of the ninth disclosure is the balloon catheter of the second disclosure, wherein the tapered portion is provided with an inner protrusion that protrudes from its inner surface and extends in the axial direction along the inner surface, and an area of ​​the outer surface of the tapered portion where the inner protrusion is provided that overlaps with the inner protrusion in the thickness direction of the tapered portion is an overlapping area, and the second area is formed in a range that includes the overlapping area on the outer surface of the tapered portion where the inner protrusion is provided.

[0026] According to the ninth disclosure, the tapered portion of the balloon is provided with an inward protrusion that protrudes from its inner surface and extends in the axial direction. In this case, the portion of the tapered portion where the inward protrusion is provided has high rigidity, so that when the balloon is inflated to dilate the lesion with the tapered portion, the tapered portion can be firmly pressed against the lesion. This makes it difficult for the tapered portion to be pushed back from the lesion when dilating the lesion with the tapered portion.

[0027] Furthermore, when the tapered portion dilates the lesion, the overlapping region of the outer surface of the tapered portion, where the inner protrusion and the tapered portion overlap in the thickness direction, firmly contacts the lesion. In this regard, in the ninth disclosure, the second region is formed in a range that includes the overlapping region on the outer surface of the tapered portion. This allows the second region to firmly contact the lesion in the overlapping region. Therefore, balloon slippage can be effectively suppressed.

[0028] The balloon catheter of a tenth disclosure is the ninth disclosure, wherein a predetermined region of the second region formed in the overlap region has a surface roughness greater than that of other regions.

[0029] According to the tenth disclosure, the predetermined area of ​​the second region formed in the overlapping region has a surface roughness greater than that of the other areas. In this case, the surface roughness is greater in the overlapping region that firmly contacts the lesion, thereby enhancing the effect of suppressing balloon slippage.

[0030] The balloon catheter of the eleventh disclosure is the ninth or tenth disclosure, wherein the straight tube portion is provided with an outer protrusion that protrudes from its outer surface and extends in the axial direction, and the inner protrusion and the outer protrusion are arranged at the same position circumferentially of the balloon.

[0031] According to the eleventh disclosure, an outer protrusion is provided on the straight tube portion of the balloon, and when the balloon is inflated, the outer protrusion makes an incision in the lesion, which triggers the dilation of the lesion. Furthermore, the inner protrusion of the tapered portion and the outer protrusion of the straight tube portion are positioned at the same position circumferentially of the balloon. In this case, the highly rigid inner protrusion and outer protrusion are aligned in the axial direction, making it even more difficult for the tapered portion to be pushed back from the lesion when the tapered portion is used to dilate the lesion.

[0032] A twelfth disclosure provides a balloon catheter according to the fifth disclosure, wherein the balloon is manufactured using a mold having an internal space for forming the balloon, the internal space having a first spatial portion forming the straight tube portion and a second spatial portion forming the tapered portion, the mold having an inner wall surface forming the internal space including a first surface portion forming the first spatial portion and a second surface portion forming the second spatial portion, the surface roughness of the second surface portion being greater than the surface roughness of the first surface portion, and the manufacturing method includes the steps of: placing a tubular parison that will be the basis of the balloon in the internal space; and expanding the parison in the internal space, wherein in the expansion step, the outer peripheral surface of the expanded parison is brought into close contact with the first surface portion to form the first region on the outer surface of the straight tube portion, and the outer peripheral surface of the expanded parison is brought into close contact with the second surface portion to form the second region on the outer surface of the tapered portion.

[0033] According to the twelfth disclosure, when the parison is expanded in the internal space of the mold, a first region is formed on the outer surface of the straight tube portion, and a second region is formed on the outer surface of the tapered portion. In this case, after expanding the parison to form the balloon, there is no need to perform a post-process, such as scraping the outer surface of the tapered portion to form the second region. This makes it possible to relatively easily manufacture the balloon catheter of the fifth disclosure described above.

[0034] The balloon catheter of the thirteenth disclosure is applied to the balloon catheter of the twelfth disclosure, in which the straight tube portion is provided with an outer protrusion protruding from its outer surface and extending in the axial direction, and the tapered portion is provided with an inner protrusion protruding from its inner surface and extending in the axial direction along the inner surface, the parison is provided with a protrusion protruding from its outer surface and extending in the longitudinal direction of the parison, the first surface portion is formed with a groove portion extending in the longitudinal direction of the internal space, and the second surface portion is not formed with the groove portion, and in the expansion process, the protrusion portion of the expanded parison is inserted into the groove portion to form the outer protrusion, and in the expansion process, the protrusion portion of the expanded parison is pressed against the second surface portion and crushed, thereby causing a portion of the parison that follows the protrusion portion to protrude inward, forming the inner protrusion, and the second region is formed on the surface that comes into close contact with the second surface portion during the crushing.

[0035] According to the thirteenth disclosure, a parison having a protrusion is expanded in the internal space of a mold, forming an outer protrusion on the straight tube portion of the balloon and an inner protrusion on the tapered portion. Specifically, the protrusion of the expanded parison is pressed against the second surface of the mold and crushed, causing a portion of the parison to protrude inward, forming an inner protrusion. Furthermore, a second region is formed on the surface of the protrusion that comes into close contact with the second surface when crushed. In this case, a second region with high surface roughness is formed on the outer surface of the tapered portion in the overlap region where the inner protrusion and the tapered portion overlap in the thickness direction. This makes it possible to relatively easily manufacture the balloon catheter of the ninth disclosure described above.

[0036] The 14th disclosure relates to a method for manufacturing a balloon according to the 13th disclosure, in which the second surface portion surrounding the second space portion is a protruding surface portion that protrudes inward in a circumferential direction, and in the inflation process, the protrusion is pressed against the protruding surface portion and crushed.

[0037] According to the fourteenth disclosure, during the expansion step, the protruding portion of the parison is pressed against the protruding surface portion of the second surface portion of the mold that protrudes toward the inner periphery, so that the protruding portion can be tightly adhered to the second surface portion (protruding surface portion). This allows the surface roughness of the second region formed in the overlap region to be further increased. [Brief explanation of the drawings]

[0038] 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 according to a first embodiment. [Figure 2] 1(a) is a side view showing the configuration of the balloon and its surroundings, and FIG. 1(b) is a side view showing the balloon and its surroundings, with the balloon and outer tube shown in longitudinal cross section. [Figure 3] FIG. 2 is a cross-sectional view showing the configuration of a mold, together with a parison placed inside the mold. [Figure 4] FIG. 1 is an explanatory diagram illustrating a method of using a balloon catheter. [Figure 5] FIG. 10 is a side view showing the configuration of a balloon and its surroundings in the second embodiment. [Figure 6] (a) is a side view showing the configuration of a balloon and its surroundings in the third embodiment, (b) is a cross-sectional view taken along line AA in (a), (c) is a cross-sectional view taken along line BB in (a), and (d) is a cross-sectional view taken along line CC in (a). [Figure 7] FIG. 2 is a side view showing the balloon and its surroundings, with the balloon and outer tube shown in longitudinal cross section. [Figure 8] FIG. [Figure 9] (a) is a cross-sectional view showing the configuration of the mold, (b) is a cross-sectional view of (a) taken along line DD, (c) is a cross-sectional view of (a) taken along line EE, and (d) is a cross-sectional view of (a) taken along line FF. [Figure 10] These are cross-sectional views showing the state in which the parison has expanded in the internal space of the mold, where (a) is a cross-sectional view taken along line DD in Figure 9(a), (b) is a cross-sectional view taken along line EE in Figure 9(a), and (c) is a cross-sectional view taken along line FF in Figure 9(a). DETAILED DESCRIPTION OF THE INVENTION

[0039] [First embodiment] 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;

[0040] 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.

[0041] 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. 2(b)) extending therein in 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.

[0042] 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.

[0043] The inner tube 16 is made of a resin material and has a tubular shape, and has a lumen 16a (see FIG. 2(b)) 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 inside the balloon 13. The distal end of the inner tube 16 is joined to the distal end of the balloon 13.

[0044] 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.

[0045] Next, the configuration of the balloon 13 and its surroundings will be described with reference to Figure 2. Figure 2(a) is a side view showing the configuration of the balloon 13 and its surroundings. Figure 2(b) is a side view showing the configuration of the balloon 13 and its surroundings, showing the balloon 13 and the outer tube 15 in a longitudinal cross section. Figures 2(a) and (b) show the inflated state of the balloon 13.

[0046] The balloon 13 is made of a thermoplastic resin material, such as polyamide elastomer. As shown in Figures 2(a) and 2(b), 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.

[0047] The proximal leg portion 13a is joined to the distal end of the outer tube 15. The proximal tapered portion 13b has a diameter that increases from the distal end of the proximal leg portion 13a toward the distal end, forming a tapered shape. The straight tube portion 13c extends from the distal end of the proximal tapered portion 13b toward the distal end with a constant diameter, forming a cylindrical shape. The straight tube portion 13c is the portion whose diameter is largest when the balloon 13 is inflated. The distal tapered portion 13d has a diameter that decreases from the distal end of the straight tube portion 13c toward the distal end, forming a tapered shape. The distal leg portion 13e is joined to the distal side of the inner tube 16.

[0048] 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. Although not shown, the balloon 13 has a plurality of wings that are formed in the deflated state. These wings are arranged at predetermined intervals around the circumference of the balloon 13, and when the balloon 13 enters the deflated state, they are folded around the circumference of the balloon 13 and wrapped around the inner tube 16.

[0049] 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.

[0050] In the present balloon catheter 10, a plurality of regions with different surface roughness are formed on the outer surface of the balloon 13. These regions will now be described.

[0051] As shown in Fig. 2(a), the outer surface of the balloon 13 is formed with a first region 21 having a small surface roughness and a second region 22 having a larger surface roughness than the first region 21. The first region 21 and the second region 22 are aligned in the axial direction of the balloon 13. In Fig. 2(a), the second region 22 is indicated by dot hatching.

[0052] The first region 21 is formed on the outer surface of the straight pipe portion 13c of the balloon 13, more specifically, on the entire outer surface of the straight pipe portion 13c. The surface roughness of the first region 21 is constant throughout the entire first region 21.

[0053] The second region 22 is formed on the outer surface of each of the proximal leg portion 13a, the proximal tapered portion 13b, the distal tapered portion 13d, and the distal leg portion 13e of the balloon 13. Specifically, the second region 22 is formed over the entire outer surface of each of the portions 13a, 13b, 13d, and 13e of the balloon 13. Therefore, the second region 22 is formed over the entire outer surface of the balloon 13 except for the region where the first region 21 is formed (the outer surface of the straight tube portion 13c). The surface roughness of the second region 22 of each of the portions 13a, 13b, 13d, and 13e is the same. The surface roughness of the second region 22 of each of the portions 13a, 13b, 13d, and 13e is constant throughout.

[0054] The surface roughness of the second region 22 of each of the above-mentioned portions 13a, 13b, 13d, and 13e of the balloon 13 does not necessarily have to be the same. For example, the surface roughness of the second region 22 of each of the tapered portions 13b and 13d may be greater or smaller than the surface roughness of the second region 22 of each of the leg portions 13a and 13e.

[0055] 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 a measuring instrument specified in JIS B0651: 2001 is used for the measurement.

[0056] 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 first be described below with reference to FIG. 3. FIG. 3 is a cross-sectional view showing the configuration of the mold 30. Note that FIG. 3 also shows a parison 39 placed inside the mold 30.

[0057] 3, 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, 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 area in the longitudinal direction.

[0058] The internal space 31 has a space 31a that forms the proximal leg portion 13a of the balloon 13, a space 31b (corresponding to the second space) that forms the proximal tapered portion 13b, a space 31c (corresponding to the first space) that forms the straight tube portion 13c, a space 31d (corresponding to the second space) 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.

[0059] The mold 30 is formed by combining a plurality of mold members. These mold members include a plurality of mold members 32 to 34 that form an internal space 31. Of the mold members 32 to 34, the mold member 32 forms a space 31c for the straight pipe portion 13c. The mold member 33 forms a space 31b for the base-end tapered portion 13b and a space 31a for the base-end leg portion 13a. The mold member 34 forms a space 31d for the tip-end tapered portion 13d and a space 31e for the tip-end leg portion 13e. The mold 30 does not necessarily have to be formed by a plurality of mold members, and may be formed by a single mold member.

[0060] The mold 30 has inner wall surfaces 37 that form the internal space 31. The inner wall surfaces 37 include an inner wall surface 37a that forms the space 31a for the base-side leg portion 13a, an inner wall surface 37b (corresponding to the second surface) that forms the space 31b for the base-side tapered portion 13b, an inner wall surface 37c (corresponding to the first surface) that forms the space 31c for the straight pipe portion 13c, an inner wall surface 37d (corresponding to the second surface) that forms the space 31d for the tip-side tapered portion 13d, and an inner wall surface 37e that forms the space 31e for the tip-side leg portion 13e. Of the inner wall surfaces 37a to 37e, the inner wall surface 37c has a smaller surface roughness, and each of the inner wall surfaces 37a, 37b, 37d, and 37e has a larger surface roughness than the inner wall surface 37c. The inner wall surfaces 37a, 37b, 37d, and 37e all have the same surface roughness. In Fig. 3, the inner wall surfaces 37a, 37b, 37d, and 37e are indicated by dot hatching.

[0061] Next, a manufacturing method for manufacturing the balloon 13 using the above-described mold 30 will be described. When manufacturing the balloon 13, first, a preparation step is performed to prepare the mold 30 and a parison 39 that will be the base of the balloon 13. The parison 39 is formed into a cylindrical shape from a resin material, for example, by extrusion molding.

[0062] Next, an arrangement step is performed in which the parison 39 is arranged in the internal space 31 of the mold 30. In this step, the parison 39 is arranged in the internal space 31 with the longitudinal direction of the parison 39 facing the longitudinal direction of the internal space 31.

[0063] Next, an expansion step is performed in which the parison 39 is heated and expanded in the internal space 31 of the mold 30. In this step, the parison 39 is expanded by introducing a fluid such as nitrogen into the interior of the parison 39. This results in the formation of an expanded parison that includes the shape of the balloon 13; in other words, the formation of an expanded parison that includes the respective portions 13a to 13e that constitute the balloon 13. Note that, before the expansion step, a stretching step may be performed in which the parison 39 is stretched in the longitudinal direction. The expansion step can also be referred to as a blow molding step in which blow molding is performed.

[0064] In the expansion step, the outer peripheral surface of the expanded parison 39 is brought into close contact with the inner wall surface 37c of the mold 30 (mold member 32), thereby forming a first region 21 on the outer surface of the straight tube portion 13c. The outer peripheral surface of the expanded parison 39 is brought into close contact with the inner wall surfaces 37a, 37b of the mold 30 (mold member 33), thereby forming a second region 22 on the outer surfaces of the base-side tapered portion 13b and the base-side leg portion 13a. The outer peripheral surface of the expanded parison 39 is brought into close contact with the inner wall surfaces 37d, 37e of the mold 30 (mold member 34), thereby forming a second region 22 on the outer surfaces of the tip-side tapered portion 13d and the tip-side leg portion 13e.

[0065] After the expansion step, a cutting step is carried out in which the excess portions on both ends of the expanded parison are cut off, thereby forming the balloon 13, and the manufacture of the balloon 13 is completed.

[0066] 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.

[0067] 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. Note that Figure 4 is an explanatory diagram for explaining this procedure.

[0068] 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 site via the lesion.

[0069] Next, the balloon catheter 10 is introduced into the guiding catheter along the guide wire G. After introduction, the balloon 13 is introduced toward the lesion 38 while being pushed and pulled. During this introduction, the balloon 13 is kept in a deflated state.

[0070] In the example of FIG. 4(a), a lesion 38 occurring in a blood vessel is relatively large. Therefore, the inside of the lesion 38 is significantly narrowed. In this case, it is expected that the balloon 13 cannot be successfully introduced into the inside of the lesion 38. For example, it is expected that the straight tube portion 13c of the balloon 13 cannot be introduced into the inside of the lesion 38. Therefore, in such a case, as shown in FIG. 4(a), the tapered distal tapered portion 13d and distal leg portion 13e of the balloon 13 are first introduced into the inside of the lesion 38. Then, the balloon 13 is inflated in this state. As a result, the inflated distal tapered portion 13d dilates the lesion 38, as shown in FIG. 4(b).

[0071] Here, when the lesion 38 is dilated by the distal tapered portion 13d, the distal tapered portion 13d abuts against the lesion 38 at an angle, and as a reaction to this, the distal tapered portion 13d is pushed obliquely by the lesion 38, which may cause the balloon 13 to slip toward the base end (proximal side). In this regard, in the balloon 13 of this embodiment, the second region 22 with large surface roughness is formed on the outer surface of the distal tapered portion 13d, and therefore the abutment of the second region 22 against the lesion 38 can be prevented, and therefore the balloon 13 can be prevented from slipping toward the base end.

[0072] Furthermore, because second region 22 is also formed on the outer peripheral surface of distal leg portion 13e, second region 22 of distal leg portion 13e introduced inside lesion 38 comes into contact with lesion 38. Therefore, distal tapered portion 13d can further prevent balloon 13 from slipping toward the base end when lesion 38 is expanded.

[0073] After the lesion 38 is dilated by the distal tapered portion 13d, the balloon 13 is deflated as shown in FIG. 4(c). Then, in this deflated state, the balloon 13 is further moved toward the distal end (distal side) so that the distal tapered portion 13d and distal leg portion 13e of the balloon 13 are introduced into the undilated portion of the lesion 38. At this time, the straight tube portion 13c of the balloon 13 is positioned inside the cone-dilated portion of the lesion 38 that has already been dilated by the distal tapered portion 13d. Then, with the balloon 13 introduced in this state, the balloon 13 is again inflated. As a result, the undilated portion of the lesion 38 is dilated by the distal tapered portion 13d (see FIG. 4(d)). The cone-dilated portion of the lesion 38 is further dilated outward by the straight tube portion 13c.

[0074] In this manner, the undilated portion of the lesion 38 is sequentially dilated from the proximal side to the distal side, and finally, the entire lesion 38 is dilated by the balloon 13, as shown in FIG.

[0075] After the lesion 38 has been dilated, the balloon 13 is deflated, and the balloon catheter 10 is removed from the body, etc. This completes the series of operations.

[0076] 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."

[0077] According to the configuration of this embodiment described above in detail, the following excellent effects can be obtained.

[0078] Because the second region 22 with high surface roughness is formed on the outer surface of the balloon 13, the second region 22 comes into contact with the lesion 38 when the balloon 13 is inflated, thereby preventing the balloon 13 from slipping. Furthermore, the second region 22 is only provided on a portion of the balloon 13 in the axial direction, and the first region 21 with low surface roughness is formed in the rest of the balloon. In this case, the sliding resistance when the balloon 13 is introduced into the blood vessel can be reduced compared to when the second region 22 is provided on the entire balloon 13 in the axial direction. This prevents a decrease in the passability of the balloon 13 and prevents the balloon 13 from slipping when inflated.

[0079] Because the straight tube portion 13c is the portion of the balloon 13 with the largest diameter, it easily slides against the vessel wall when the balloon 13 is introduced into the blood vessel. In this regard, the first region 21, which has a small surface roughness, is formed on the outer surface of the straight tube portion 13c, so that the sliding resistance when the balloon 13 is introduced into the blood vessel can be suitably reduced. This makes it possible to suitably reduce the passability of the balloon 13.

[0080] In addition to distal tapered portion 13d, second region 22 is also formed on the outer surface of proximal tapered portion 13b. As a result, when balloon 13 is inflated to expand the lesion with proximal tapered portion 13b, even if proximal tapered portion 13b is pushed obliquely from the lesion, proximal tapered portion 13b can be prevented from slipping toward the distal end, and ultimately balloon 13 can be prevented from slipping toward the distal end.

[0081] Because the second region 22 is provided over the entire circumferential area of ​​the balloon 13, even if the lesion 38 is formed only partially around the circumference of the blood vessel, the second region 22 can be reliably brought into contact with the lesion 38 when the balloon 13 is inflated. This reliably prevents the balloon 13 from slipping when inflated.

[0082] During the expansion process in which the parison 39 is expanded in the internal space 31 of the mold 30, the first region 21 is formed on the outer surface of the straight tube portion 13c, and the second region 22 is formed on the outer surfaces of the tapered portions 13b and 13d. In this case, after the parison 39 is expanded to form the balloon 13, there is no need to perform a post-process, such as scraping the outer surfaces of the tapered portions 13b and 13d to form the second region 22. This makes it relatively easy to manufacture a balloon 13 having the first region 21 and the second region 22 with different surface roughnesses.

[0083] [Second embodiment] Next, a second embodiment will be described. In this embodiment, the surface roughness of the second region formed on the outer surface of each of the tapered portions 13b, 13d of the balloon 13 varies in the axial direction of the balloon 13. This is the difference between this embodiment and the first embodiment, and this difference will be described below. Note that FIG. 5 is a side view showing the configuration of the balloon 13 and its surroundings in this embodiment.

[0084] As shown in Fig. 5, the balloon 13 of this embodiment has a first region 21 formed on the outer surface of the straight tube portion 13c, and a second region 22 formed on the outer surface of each of the proximal leg portion 13a and the distal leg portion 13e. These regions 21 and 22 have the same configuration as in the first embodiment, and therefore will not be described here. In Fig. 5, the second region 22 is indicated by dot hatching.

[0085] In the balloon 13 of this embodiment, second regions 42 having a surface roughness greater than that of the first region 21 are formed on the outer surfaces of the proximal tapered portion 13b and the distal tapered portion 13d. In FIG. 5, these second regions 42 are indicated by dot hatching. Of the second regions 42, the second region 42b of the proximal tapered portion 13b is formed over the entire outer surface of the proximal tapered portion 13b. The surface roughness of the second region 42b gradually decreases from the proximal side toward the distal side. The surface roughness of the second region 42b is greater than that of the first region 21 of the straight tube portion 13c over the entire region. Furthermore, the surface roughness of the second region 42b is smaller than that of the second region 22 of the proximal leg portion 13a over the entire region.

[0086] The surface roughness of the second region 42d of the distal tapered portion 13d gradually decreases from the distal end toward the proximal end. The second region 42d is formed over the entire outer surface of the distal tapered portion 13d. The surface roughness of the second region 42d over the entire area is greater than the surface roughness of the first region 21 of the straight pipe portion 13c. Furthermore, the surface roughness of the second region 42d over the entire area is less than the surface roughness of the second region 22 of the distal leg portion 13e.

[0087] As described above, the surface roughness of each of the second regions 42b, 42d of the tapered portions 13b, 13d gradually decreases as the region approaches the straight pipe portion 13c. In other words, the surface roughness of each of the second regions 42b, 42d of the tapered portions 13b, 13d gradually increases as the region moves away from the straight pipe portion 13c.

[0088] The balloon 13 of this embodiment described above is manufactured using the same procedure as in the first embodiment. As described above, the surface roughness of the second regions 42b, 42d of the tapered portions 13b, 13d of the balloon 13 of this embodiment differs from that of the balloon 13 of the first embodiment. Therefore, a mold 30 (see FIG. 3) is used to manufacture the balloon 13, and the surface roughness of the inner wall surfaces 37b, 37d corresponds to the surface roughness of the second regions 42b, 42d.

[0089] According to the configuration of this embodiment described above in detail, the following excellent effects can be obtained.

[0090] In the balloon 13, a first region 21 with low surface roughness is formed on the outer surface of the straight tube portion 13c, a second region 42 with high surface roughness is formed on the outer surface of each of the tapered portions 13b and 13d, and a second region 22 with high surface roughness is formed on the outer surface of each of the leg portions 13a and 13e. This provides the same effects as in the first embodiment.

[0091] The tapered portions 13b and 13d have a relatively large diameter at the portion closest to the straight tube portion 13c. Therefore, when the balloon 13 is introduced into a blood vessel, the portion closest to the straight tube portion 13c is likely to slide easily against the vessel wall. In light of this, the above-described embodiment configures the second regions 42b and 42d of the tapered portions 13b and 13d so that the surface roughness decreases toward the straight tube portion 13c. This reduces the sliding resistance of the tapered portions 13b and 13d at the portion closest to the straight tube portion 13c when the balloon 13 is introduced into the blood vessel. Therefore, the sliding resistance when the balloon 13 is introduced into the blood vessel can be further reduced.

[0092] Furthermore, the diameter of the distal tapered portion 13d is relatively small at the portion away from the straight tube portion 13c (i.e., the distal portion). Therefore, the portion away from the straight tube portion 13c is easily introduced into the narrowed portion. In this regard, in the above embodiment, the surface roughness of the second region 42d of the distal tapered portion 13d increases with increasing distance from the straight tube portion 13c. Therefore, when the distal tapered portion 13d is introduced into the narrowed portion and the balloon 13 is inflated, the distal tapered portion 13d is prevented from slipping toward the base end, and therefore the balloon 13 is prevented from slipping toward the base end.

[0093] [Third embodiment] Next, a third embodiment will be described. In this embodiment, linear protrusions are provided on the outer and inner surfaces of the balloon 13. Therefore, these protrusions will be described below first with reference to Figs. 6 and 7. In Fig. 6, (a) is a side view showing the configuration of the balloon 13 and its surroundings in this embodiment, (b) is a cross-sectional view taken along line AA in (a), (c) is a cross-sectional view taken along line BB in (a), and (d) is a cross-sectional view taken along line CC in (a). Note that Figs. 6(a) to (d) show the inflated state of the balloon 13. Furthermore, Fig. 7 is a side view showing the balloon 13 and its surroundings, showing the balloon 13 and the outer tube 15 in longitudinal cross section.

[0094] 6(a) to 6(d) and 7, the balloon 13 has an outer protrusion 51 on its straight tube portion 13c, an inner protrusion 52 on its proximal tapered portion 13b, and an inner protrusion 53 on its distal tapered portion 13d. These protrusions 51 to 53 are integrally formed with the balloon 13.

[0095] The outer protrusions 51 protrude from the outer surface of the straight pipe portion 13c and extend in the axial direction of the balloon 13 along the outer surface of the straight pipe portion 13c. More specifically, the outer protrusions 51 extend over the entire axial direction of the straight pipe portion 13c. A plurality of outer protrusions 51 (specifically, three) are arranged at predetermined intervals (specifically, equal intervals) around the circumference of the balloon 13. Each outer protrusion 51 has a cross section (specifically, a cross section perpendicular to the longitudinal direction of the outer protrusion 51) that forms a mountain shape that protrudes radially outward from the balloon 13, more specifically, a triangular shape.

[0096] The outer protrusion 51 makes an incision in the lesion when the balloon 13 is inflated to dilate the lesion. In the present balloon catheter 10, the outer protrusion 51 makes an incision in the lesion, which facilitates dilation of the lesion. Therefore, the present balloon catheter 10 is a balloon catheter with a scoring function.

[0097] The inward protrusions 52 of the proximal tapered portion 13b protrude from the inner surface of the proximal tapered portion 13b and extend in the axial direction of the balloon 13 along the inner surface of the proximal tapered portion 13b. More specifically, the inward protrusions 52 extend across the entire axial direction of the proximal tapered portion 13b. A plurality of the inward protrusions 52 (three in this embodiment) are arranged at predetermined intervals (more specifically, equal intervals) in the circumferential direction of the balloon 13. Each of the inward protrusions 52 is arranged at the same position as each of the outer protrusions 51 in the circumferential direction of the balloon 13. Each of the inward protrusions 52 has a cross section (more specifically, a cross section perpendicular to the longitudinal direction of the inward protrusions 52) that is semicircular and convex toward the inside of the balloon 13.

[0098] The inward protrusions 53 of the distal tapered portion 13d protrude from the inner surface of the distal tapered portion 13d and extend in the axial direction of the balloon 13 along the inner surface of the distal tapered portion 13d. More specifically, the inward protrusions 53 extend across the entire axial direction of the distal tapered portion 13d. A plurality of inward protrusions 53 (three in this embodiment) are arranged at predetermined intervals (more specifically, equal intervals) in the circumferential direction of the balloon 13. Each of these inward protrusions 53 is arranged at the same position as each of the outer protrusions 51 in the circumferential direction of the balloon 13. Furthermore, the cross section of each inward protrusion 53 (more specifically, a cross section perpendicular to the longitudinal direction of the inward protrusion 53) has a semicircular shape that is convex toward the inside of the balloon 13.

[0099] The outer surface of the balloon 13 is formed with a first region 55 having a small surface roughness and second regions 56-59 having a larger surface roughness than the first region 55. These regions 55-59 will be described below with reference to Fig. 6(a). In Fig. 6(a), the second regions 56-59 are indicated by dot hatching.

[0100] 6(a), in the balloon 13, a first region 55 is formed on the outer surface of the straight tube portion 13c, a second region 56 is formed on the outer surface of the base-side leg portion 13a, a second region 57 is formed on the outer surface of the distal-side leg portion 13e, a second region 58 is formed on the outer surface of the base-side tapered portion 13b, and a second region 59 is formed on the outer surface of the distal-side tapered portion 13d. The first region 55 of the straight tube portion 13c is formed over the entire outer surface of the straight tube portion 13c. The surface roughness of the first region 55 is constant over the entire first region 55.

[0101] The second region 56 of the proximal leg 13a is formed over the entire outer surface of the proximal leg 13a. The second region 57 of the distal leg 13e is formed over the entire outer surface of the distal leg 13e. The second regions 56, 57 have the same surface roughness. The surface roughness of each of the second regions 56, 57 is constant throughout its entire area.

[0102] The second region 58 of the base-side tapered portion 13b is formed over the entire outer surface of the base-side tapered portion 13b. The region of the outer surface of the base-side tapered portion 13b where the inward protrusion 52 and the base-side tapered portion 13b overlap in the thickness direction is the overlapping region 45. More specifically, the overlapping region 45 is a region that overlaps with the inward protrusion 52 in the thickness direction on the side opposite to the protruding side of the inward protrusion 52. The outer surface of the base-side tapered portion 13b includes the overlapping region 45 of each inward protrusion 52. Each overlapping region 45 extends in an elongated shape along the inward protrusion 52.

[0103] The second region 58 of the base-side tapered portion 13b includes a plurality of (specifically, three) second regions 58a formed in each overlap region 45 of the outer surface of the base-side tapered portion 13b, and a second region 58b formed in a region other than the overlap region 45. The surface roughness of each second region 58a is greater than the surface roughness of the second region 58b. The surface roughness of each second region 58a is the same. The second region 58a corresponds to the "predetermined region formed in the overlap region," and the second region 58b corresponds to the "other region."

[0104] The second region 59 of the tip side tapered portion 13d is formed over the entire outer surface of the tip side tapered portion 13d. The region of the outer surface of the tip side tapered portion 13d where the inner protrusion 53 and the tip side tapered portion 13d overlap in the thickness direction is the overlapping region 46. More specifically, the overlapping region 46 is a region that overlaps with the inner protrusion 53 in the thickness direction on the side opposite to the protruding side of the inner protrusion 53. The outer surface of the tip side tapered portion 13d includes the overlapping region 46 of each inner protrusion 53. Each overlapping region 46 extends in an elongated shape along the inner protrusion 53.

[0105] The second region 59 of the tip-side tapered portion 13d includes a plurality of (specifically, three) second regions 59a formed in each overlapping region 46 of the outer surface of the tip-side tapered portion 13d, and a second region 59b formed in a region other than the overlapping region 46. The surface roughness of each second region 59a is greater than the surface roughness of the second region 59b. The surface roughness of each second region 59a is the same. The second region 59a corresponds to the "predetermined region formed in the overlapping region," and the second region 59b corresponds to the "other region."

[0106] Next, a manufacturing method for manufacturing the balloon 13 of this embodiment will be described. In this embodiment, since the balloon 13 is provided with an outer protruding portion 51 and inner protruding portions 52, 53, the configurations of the parison 47 and mold 60 used to manufacture the balloon 13 differ from those of the first embodiment. Therefore, the configurations of the parison 47 and mold 60 will first be described below. FIG. 8 is a perspective view showing the parison 47. Also, FIG. 9(a) is a cross-sectional view showing the configuration of the mold 60, (b) is a cross-sectional view taken along line DD of (a), (c) is a cross-sectional view taken along line EE of (a), and (d) is a cross-sectional view taken along line FF of (a).

[0107] First, the configuration of the parison 47 will be described with reference to FIG. 8. As shown in FIG. 8, the parison 47 is formed from a resin material in a generally cylindrical shape, for example, by extrusion molding. The parison 47 has a plurality of (specifically, three) protrusions 48 protruding from its outer circumferential surface. The cross section of each of the protrusions 48 (specifically, a cross section perpendicular to the longitudinal direction of the parison 47) has a mountain-like shape (specifically, a triangular shape) that protrudes radially outward from the parison 47. Each of the protrusions 48 extends in the longitudinal direction of the parison 47, specifically, over the entire longitudinal length of the parison 47. The protrusions 48 form the outer protrusion 51 and the inner protrusions 52 and 53 of the balloon 13.

[0108] Next, the configuration of the mold 60 will be described with reference to Figures 9(a) to 9(d). As shown in Figure 9(a), the mold 60 has basically the same configuration as the mold 30 of the first embodiment. The mold 60 has an internal space 61 therein for forming the balloon 13. The internal space 61 extends in the longitudinal direction of the mold 60 and has a space 61a for forming the proximal leg portion 13a of the balloon 13, a space 61b (corresponding to the second space) for forming the proximal tapered portion 13b, a space 61c (corresponding to the first space) for forming the straight tube portion 13c, a space 61d (corresponding to the second space) for forming the distal tapered portion 13d, and a space 61e for forming the distal leg portion 13e.

[0109] The mold 60 has a plurality of mold members 62 to 64 that form an internal space 61. Of the mold members 62 to 64, the mold member 62 forms a space 61c for the straight pipe portion 13c. The mold member 63 forms a space 61b for the base-end tapered portion 13b and a space 61a for the base-end leg portion 13a. The mold member 64 forms a space 61d for the tip-end tapered portion 13d and a space 61e for the tip-end leg portion 13e.

[0110] The mold 60 has inner wall surfaces 67 that form the internal space 61. The inner wall surfaces 67 include an inner wall surface 67a that forms a space 61a for the base-side leg portion 13a, an inner wall surface 67b (corresponding to a second surface) that forms a space 61b for the base-side tapered portion 13b, an inner wall surface 67c (corresponding to a first surface) that forms a space 61c for the straight pipe portion 13c, an inner wall surface 67d (corresponding to a second surface) that forms a space 61d for the tip-side tapered portion 13d, and an inner wall surface 67e that forms a space 61e for the tip-side leg portion 13e. Of the inner wall surfaces 67a to 67e, the inner wall surface 67c has a smaller surface roughness, and each of the inner wall surfaces 67a, 67b, 67d, and 67e has a larger surface roughness than the inner wall surface 67c. The inner wall surfaces 67a, 67b, 67d, and 67e all have the same surface roughness, and in Fig. 9(a), the inner wall surfaces 67a, 67b, 67d, and 67e are indicated by dot hatching.

[0111] In the mold 60 of this embodiment, the cross-sectional shape of the internal space 61 (in other words, the cross-sectional shape of the inner wall surface 67) differs for each of the spaces 61a to 61e. Therefore, the configuration of each of the spaces 61a to 61e will be described in order below.

[0112] First, the space 61c for the straight pipe section 13c will be described with reference to FIG. 9(b). As shown in FIG. 9(b), the space 61c for the straight pipe section 13c has a circular cross section (specifically, a cross section perpendicular to the longitudinal direction of the internal space 61). A plurality of (specifically, three) grooves 68 are formed in an inner wall surface 67c surrounding the space 61c. These grooves 68 extend in the longitudinal direction of the internal space 61, specifically, across the entire area of ​​the inner wall surface 67c in the longitudinal direction. The grooves 68 are also disposed at equal intervals around the circumferential direction of the inner wall surface 67c. Each groove 68 has a triangular cross section that is convex toward the outer periphery of the space 61c. The groove 68 is formed only on the inner wall surface 67c among the inner wall surfaces 67a to 67e, and is not formed on the other inner wall surfaces 67a, 67b, 67d, and 67e.

[0113] Next, the space 61d for the tip side tapered portion 13d will be described with reference to Fig. 9(c) in addition to Fig. 9(a). As shown in Fig. 9(a), an inner wall surface 67d surrounding the space 61d for the tip side tapered portion 13d is an inclined surface that is inclined with respect to the axial direction of the internal space 61. This inclined surface (tapered surface) is formed in accordance with the inclination of the outer surface of the tip side tapered portion 13d.

[0114] As shown in FIG. 9(c), the cross section of the space portion 61d is non-circular. An inner wall surface 67d surrounding the space portion 61d has a circumferential portion forming a protruding surface portion 71 that protrudes inward from the inner wall surface 67d. The protruding surface portion 71 extends in the axial direction of the internal space 61 along the slope of the inner wall surface 67d and is flat. More specifically, the protruding surface portion 71 extends over the entire axial direction of the inner wall surface 67d. A plurality of protruding surface portions 71 (specifically, three protruding surface portions 71) are arranged at equal intervals in the circumferential direction of the inner wall surface 67d. Each protruding surface portion 71 is arranged at the same position as each groove portion 68 in the circumferential direction of the inner wall surface 67d (in other words, the circumferential direction of the internal space 61).

[0115] The portions of the inner wall surface 67d that connect the adjacent protruding surface portions 71 are arcuate surface portions 72 that have an arc-shaped cross section that convex toward the outer periphery of the inner wall surface 67d. A plurality of arcuate surface portions 72 (specifically, three arcuate surface portions 72) are provided for each adjacent protruding surface portion 71.

[0116] The surface roughness of inner wall surface 67d is greater than the surface roughness of inner wall surface 67c. The surface roughness of inner wall surface 67d is constant over the entire area of ​​inner wall surface 67d, including protruding surface portion 71 and arcuate surface portion 72.

[0117] Next, the space 61b for the base-end tapered portion 13b will be described. As shown in Fig. 9(a), an inner wall surface 67b surrounding the space 61b for the base-end tapered portion 13b is an inclined surface that is inclined with respect to the axial direction of the internal space 61. This inclined surface (tapered surface) is formed in accordance with the inclination of the outer surface of the base-end tapered portion 13b.

[0118] Although not shown in the drawings, the space portion 61b has the same cross-sectional shape as the space portion 61d for the tip-side tapered portion 13d. A part of the inner wall surface 67b surrounding the space portion 61b forms a protruding surface portion 73 that protrudes inward. The protruding surface portion 73 extends in the axial direction of the internal space 61 along the slope of the inner wall surface 67b and is flat. More specifically, the protruding surface portion 73 extends over the entire axial direction of the inner wall surface 67b. Furthermore, a plurality of protruding surface portions 73 (specifically, three) are arranged at equal intervals in the circumferential direction of the inner wall surface 67b. Each protruding surface portion 73 is arranged at the same position as each groove portion 68 in the circumferential direction of the inner wall surface 67b.

[0119] The portions of the inner wall surface 67b connecting the adjacent protruding surface portions 73 are arcuate surface portions 74 that have an arc-shaped cross section that convex toward the outer periphery of the inner wall surface 67b. A plurality of arcuate surface portions 74 (specifically, three arcuate surface portions 74) are provided for each adjacent protruding surface portion 73.

[0120] The surface roughness of inner wall surface 67b is greater than the surface roughness of inner wall surface 67c. The surface roughness of inner wall surface 67b is constant over the entire area of ​​inner wall surface 67b, including protruding surface portion 73 and arcuate surface portion 74.

[0121] 9(d), the space 61e for the distal leg portion 13e has a circular cross section. Similarly, the space 61a for the proximal leg portion 13a also has a circular cross section.

[0122] Next, a manufacturing method for manufacturing the balloon 13 of this embodiment using the above-described mold 60 will be described.

[0123] First, a preparation step is performed to prepare the mold 60 and the parison 47. Next, an arrangement step is performed to arrange the parison 47 in the internal space 61 of the mold 60. In this step, the parison 47 is arranged in the internal space 61 with the longitudinal direction of the parison 47 facing the longitudinal direction of the internal space 61. As a result, the parison 47 is arranged in the internal space 61 across each of the space portions 61a to 61e.

[0124] Next, an expansion step is performed in which the parison 47 is heated and expanded in the internal space 61 of the mold 60. By performing this step, an expanded parison body including the shape of the balloon 13 is formed, in other words, an expanded parison body including each of the portions 13a to 13e of the balloon 13 is formed.

[0125] Next, the expansion step will be described in more detail with reference to Figures 10(a) to 10(c). Figure 10 is a cross-sectional view showing the parison 47 expanded in the internal space 61 of the mold 60, where (a) is a cross-sectional view taken along line DD in Figure 9(a), (b) is a cross-sectional view taken along line EE in Figure 9(a), and (c) is a cross-sectional view taken along line FF in Figure 9(a).

[0126] In the expansion step, the outer peripheral surface of the expanded parison 47 is brought into close contact with the inner wall surface 67c of the mold 60 (mold member 62), thereby forming a first region 55 on the outer surface of the straight pipe portion 13c. At this time, as shown in FIG. 10(a), each of the protrusions 48 of the parison 47 is inserted into each of the grooves 68 to form outer protrusions 51. That is, in this case, the protrusions 48 inserted into each of the grooves 68 become the outer protrusions 51.

[0127] In the expansion step, the outer peripheral surface of the expanded parison 47 is brought into close contact with the inner wall surface 67d of the mold 60 (mold member 64), thereby forming second regions 59 on the outer surface of the tip-side tapered portion 13d. Specifically, as shown in FIG. 10(b), each protrusion 48 of the expanded parison 47 is pressed against each protruding surface 71 of the mold 60 and crushed, causing portions 78 of the parison 47 that extend along each protrusion 48 to protrude inward, thereby forming inner protrusions 53. At the same time, second regions 59a are formed on the surfaces of the protrusions 48 that come into close contact with the protruding surface 71 when the protrusions 48 are crushed. As a result, second regions 59a are formed in each overlapping region 46 of the tip-side tapered portion 13d.

[0128] In the expansion step, the outer peripheral surface of the expanded parison 47 is brought into close contact with the inner wall surface 67b of the mold 60 (mold member 63), thereby forming second regions 58 on the outer surface of the base-side tapered portion 13b. Specifically, at this time, the protruding portions 48 of the expanded parison 47 are pressed against the protruding surface portions 73 of the mold 60 and crushed, causing the portions of the parison 47 that extend along the protruding portions 48 to protrude inward, thereby forming inner protruding portions 52. At the same time, second regions 58a are formed on the surfaces of the protruding portions 48 that are in close contact with the protruding surface portions 73 when the protruding portions 48 are crushed. As a result, second regions 58a are formed in the overlapping regions 45 of the base-side tapered portion 13b.

[0129] In the expansion step, the outer peripheral surface of the expanded parison 47 is brought into close contact with the inner wall surface 67e of the mold 60 (mold member 64), thereby forming a second region 57 on the outer surface of the distal leg portion 13e, and the outer peripheral surface of the expanded parison 47 is brought into close contact with the inner wall surface 67a of the mold 60 (mold member 63), thereby forming a second region 56 on the outer surface of the proximal leg portion 13a. At this time, each of the protrusions 48 of the parison 47 is pressed against the inner wall surfaces 67a, 67e and crushed.

[0130] After the expansion step, a cutting step is carried out in which the excess portions on both ends of the expanded parison are cut off, thereby forming the balloon 13, and the manufacture of the balloon 13 is completed.

[0131] 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.

[0132] According to the configuration of this embodiment described above in detail, the following excellent effects can be obtained.

[0133] In the balloon 13, a first region 55 having a small surface roughness is formed on the outer surface of the straight tube portion 13c, and second regions 56 to 59 having a large surface roughness are formed on the outer surfaces of the tapered portions 13b, 13d and the leg portions 13a, 13e, thereby achieving the same effects as in the first embodiment.

[0134] Tapered portions 13b and 13d of balloon 13 are provided with inward protrusions 52 and 53 that protrude from the inner surfaces and extend in the axial direction. In this case, the portions of tapered portions 13b and 13d where inward protrusions 52 and 53 are provided have high rigidity, so that when balloon 13 is inflated to dilate lesion 38 with tapered portions 13b and 13d, these portions of tapered portions 13b and 13d can be firmly pressed against lesion 38. This makes it difficult for tapered portions 13b and 13d to be pushed back from lesion 38 when lesion 38 is dilated with tapered portions 13b and 13d.

[0135] Furthermore, when the tapered portions 13b and 13d dilate the lesion 38, overlapping regions 45 and 46 on the outer surfaces of the tapered portions 13b and 13d, which overlap the inward protrusions 52 and 53 in the thickness direction of the tapered portions 13b and 13d, firmly contact the lesion 38. In this regard, in the above embodiment, the second regions 58 and 59 are formed on the outer surfaces of the tapered portions 13b and 13d in a range including the overlapping regions 45 and 46 (more specifically, the entire outer surfaces of the tapered portions 13b and 13d). This allows the second regions 58 and 59 to firmly contact the lesion 38 in the overlapping regions 45 and 46. This effectively prevents the balloon 13 from slipping.

[0136] Of the second regions 58, 59 of the tapered portions 13b, 13d, the second regions 58a, 59a formed in the overlapping regions 45, 46 have a greater surface roughness than the other regions 58b, 59b. In this case, the surface roughness is greater in the overlapping regions 45, 46 that firmly contact the lesion 38, thereby enhancing the slippage suppression effect of the balloon 13.

[0137] The inner protrusions 52, 53 of the tapered portions 13b, 13d and the outer protrusion 51 of the straight tube portion 13c are disposed at the same position in the circumferential direction of the balloon 13. In this case, the highly rigid inner protrusions 52, 53 and the outer protrusion 51 are aligned in the axial direction, which makes it even more difficult for the tapered portions 13b, 13d to be pushed back from the lesion 38 when the lesion 38 is expanded by the tapered portions 13b, 13d.

[0138] [Other embodiments] The present disclosure is not limited to the above-described embodiment, and may be implemented, for example, as follows.

[0139] In the above embodiments, the second region having a large surface roughness is formed on the outer surface of each of the tapered portions 13b, 13d, but the second region may be formed on only one of the tapered portions 13b, 13d. In this case, the first region having a small surface roughness is formed on the other tapered portion.

[0140] In addition, in the above-described embodiments, the second region is formed on the outer surface of each of the leg portions 13a, 13e, but the first region may be formed on either one or both of the leg portions 13a, 13e.

[0141] In the second embodiment, the surface roughness of the second regions 42b, 42d of the tapered portions 13b, 13d decreases toward the straight pipe portion 13c, but this may be changed. For example, on the outer surface of each tapered portion 13b, 13d, a first region may be formed on the straight pipe portion 13c side, and a second region may be formed on the opposite side from the straight pipe portion 13c side. In this case, the same effects as those of the second embodiment can be obtained.

[0142] In the above embodiments, the first region is formed over the entire outer surface of the straight pipe section 13c. However, the first region may be formed only over a portion of the outer surface of the straight pipe section 13c. For example, the first region may be formed only on the central side of the outer surface of the straight pipe section 13c in the axial direction, and the second region may be formed on the base end and tip end sides in the axial direction. In this case, the slippage suppression effect of the balloon 13 can be improved.

[0143] In the above embodiments, the second region is provided on the outer surface of the tapered portions 13b, 13d over the entire circumferential area of ​​the balloon 13, but this may be modified so that the second region is provided only over a portion of the outer surface of the tapered portions 13b, 13d in the circumferential area of ​​the balloon 13. In this case, the first region is formed on the outer surface of the tapered portions 13b, 13d except for the portion.

[0144] In the third embodiment, the inward protrusions 52 and 53 are provided on the tapered portions 13b and 13d, respectively. However, an inward protrusion may be provided on only one of the tapered portions 13b and 13d.

[0145] In the third embodiment, a portion of the inner wall surface 67d of the mold 60 is formed as the protruding surface 71, but the protruding surface 71 may not be provided. For example, the cross-sectional shape of the inner wall surface 67d (in other words, the space 61d) may be circular. In this case, too, when the parison 47 is expanded, the protruding portion 48 of the parison 47 is pressed against the inner wall surface 67d and crushed, thereby forming the inner protruding portion 53. Furthermore, when the protruding portion 48 is crushed, the second region 59a can be formed on the surface that comes into close contact with the inner wall surface 67d.

[0146] Similarly, the inner wall surface 67b of the mold 60 may also be circular in cross section without providing the protruding surface portion 73.

[0147] In the above embodiments, the first and second regions are formed on the outer surface of the balloon 13 using a mold during the expansion process, but the method for forming these regions is not necessarily limited to this. For example, the first and second regions may be formed by, for example, scraping the outer surface of the balloon 13 after manufacturing the balloon 13.

[0148] 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]

[0149] 10...balloon catheter, 11...catheter body, 13...balloon, 13a...base end leg portion, 13b...base end tapered portion, 13c...straight tube portion, 13d...tip end tapered portion, 13e...tip end leg portion, 21...first region, 22...second region, 30...mold, 31...internal space, 42b...second region, 42d...second region, 51...outer protrusion, 52...inner protrusion, 53...inner protrusion, 55...first region, 56-59...second region, 60...mold, 61...internal space.

Claims

1. A balloon catheter comprising an inflatable and deflatable balloon, The outer surface of the balloon is formed with a first region and a second region that is provided in a part of the axial direction of the balloon and has a surface roughness greater than that of the first region, The balloon is A straight pipe section whose diameter becomes the largest when expanded; a pair of tapered portions provided on both sides of the straight pipe portion in the axial direction, the tapered portions having a diameter reduced toward the side away from the straight pipe portion, the second region is formed on an outer surface of the tapered portion, the first region is formed on the outer surface of the straight pipe portion, A balloon catheter, wherein the second region of the tapered portion has a surface roughness that decreases as it approaches the straight tube portion.

2. A balloon catheter comprising an inflatable and deflatable balloon, The outer surface of the balloon is formed with a first region and a second region that is provided in a part of the axial direction of the balloon and has a surface roughness greater than that of the first region, The balloon is A straight pipe section whose diameter becomes the largest when expanded; a pair of tapered portions provided on both sides of the straight pipe portion in the axial direction, the tapered portions having a diameter reduced toward the side away from the straight pipe portion, the second region is formed on an outer surface of the tapered portion, The tapered portion is provided with an inner protrusion that protrudes from an inner surface thereof and extends in the axial direction along the inner surface, an overlapping region of the outer surface of the tapered portion on which the inner protrusion is provided overlaps with the tapered portion in a thickness direction; the second region is formed in a range including the overlap region on the outer surface of the tapered portion where the inner protrusion is provided, A balloon catheter, wherein a predetermined area of ​​the second region formed in the overlapping region has a surface roughness greater than that of other areas.

3. The straight pipe portion is provided with an outer protruding portion that protrudes from an outer surface thereof and extends in the axial direction, The balloon catheter according to claim 2 , wherein the inner protrusion and the outer protrusion are disposed at the same position in the circumferential direction of the balloon.

4. The balloon catheter according to claim 2 , wherein the first region is formed on an outer surface of the straight tube portion.

5. The balloon catheter according to claim 1 , wherein the second region is formed on an outer surface of the distal end of the pair of tapered portions.

6. a catheter body having the balloon provided at its distal end, the balloon has a distal leg portion that is provided on the opposite side of the straight tube portion across the distal tapered portion and is joined to the catheter main body, The balloon catheter according to claim 5 , wherein the second region is formed on an outer surface of the distal leg portion.

7. a catheter body having the balloon provided at its distal end, the balloon has a leg portion that is provided on the opposite side of the straight tube portion across the tapered portion in which the second region is formed, and that is joined to the catheter main body; The balloon catheter according to claim 1 , wherein the second region is formed on an outer surface of the leg portion.

8. The balloon catheter according to claim 1 , wherein the second region is provided over the entire circumferential area of ​​the balloon.

9. A method for manufacturing the balloon catheter according to claim 1 or 4, comprising the steps of: The balloon is manufactured using a mold having an interior space for forming the balloon; the internal space has a first space portion that forms the straight pipe portion and a second space portion that forms the tapered portion, an inner wall surface of the mold that forms the internal space includes a first surface portion that forms the first space portion and a second surface portion that forms the second space portion; The surface roughness of the second surface portion is greater than the surface roughness of the first surface portion, a placement step of placing a tubular parison, which is the base of the balloon, in the internal space; and an expansion step of expanding the parison in the internal space, In the expansion step, the outer peripheral surface of the expanded parison is brought into close contact with the first surface portion to form the first region on the outer surface of the straight tube portion, and the outer peripheral surface of the expanded parison is brought into close contact with the second surface portion to form the second region on the outer surface of the tapered portion.

10. The straight pipe portion is provided with an outer protruding portion that protrudes from an outer surface thereof and extends in the axial direction, The present invention is applied to a balloon catheter, wherein the tapered portion is provided with an inner protrusion protruding from an inner surface thereof and extending in the axial direction along the inner surface, The parison is provided with a protrusion protruding from its outer circumferential surface and extending in the longitudinal direction of the parison, A groove extending in the longitudinal direction of the internal space is formed in the first surface portion, The second surface portion does not have the groove portion formed thereon, In the expanding step, the protrusion of the expanded parison is inserted into the groove to form the outer protrusion, 10. The method for manufacturing a balloon catheter according to claim 9, wherein in the expansion step, the protruding portion of the expanded parison is pressed against the second surface portion and crushed, thereby causing a portion of the parison that follows the protruding portion to protrude inward to form the inner protruding portion, and forming the second region on a surface that comes into close contact with the second surface portion during the crushing step.

11. The second surface portion surrounding the second space portion is a protruding surface portion whose circumferential portion protrudes inward, The method for manufacturing a balloon catheter according to claim 10, wherein the expanding step presses the protruding portion against the protruding surface portion to crush it.

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