Balloon catheter and balloon catheter manufacturing method

Abstract

A balloon (13) of a balloon catheter (10) has a base-end-side branch tube section (13a), a base-end-side tapered section (13b), a straight tube section (13c), a tip-end-side tapered section (13d), and a tip-end-side branch tube section (13e). A first region (21) and a second region (22) having a higher 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 section (13c), and the second region (22) is formed on the outer surfaces of the base-end-side branch tube section (13a), the base-end-side tapered section (13b), the tip-end-side tapered section (13d), and the tip-end-side branch tube section (13e).

Description

[0001] Cross-references of related applications

[0002] This application is based on Japanese application No. 2022-192304 filed on November 30, 2022, and the contents thereof are incorporated herein by reference. Technical Field

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

[0004] Conventionally, balloon catheters are used in treatments such as PTA (percutaneous transluminal angioplasty) and PTCA (percutaneous coronary angioplasty). The balloon catheter has a balloon that can expand and contract at its front end (see, for example, Patent Document 1). In the balloon catheter, the balloon is introduced in a contracted state into a site that is narrowed or occluded due to a lesion or the like generated in a blood vessel, and then the site is expanded by inflating the balloon.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: International Publication No. 2020 / 255923 Summary of the invention

[0008] Problems to be solved by the invention

[0009] However, when the lesion in the body is expanded by inflating the balloon, it is conceivable that the balloon is pressed by the lesion and slips in the axial direction. In this case, the lesion may not be expanded smoothly using the balloon.

[0010] Therefore, in order to prevent the balloon from slipping when inflating, it is considered to increase the surface roughness of the outer surface of the balloon. For example, it is considered to increase the surface roughness of the outer surface in the entire area of ​​the axial direction of the balloon. However, if this structure is adopted, the sliding resistance when the balloon is introduced into a tube such as a blood vessel becomes larger, and the passability of the balloon in the tube may be reduced.

[0011] The present disclosure has been made in view of the above circumstances, and its main object is to provide a balloon catheter and a method for manufacturing the balloon catheter that can suppress a decrease in passability when the balloon is introduced into a tube and suppress slippage of the balloon when the balloon is inflated.

[0012] Means for solving problems

[0013] To solve the above problems, a first disclosed balloon catheter includes an expandable and deflable balloon, wherein the outer surface of the balloon includes a first region and a second region provided in a portion of the balloon in an axial direction and having a surface roughness greater than that of the first region.

[0014] According to the first disclosure, a first region and a second region with a surface roughness greater than that of the first region are formed on the outer surface of the balloon. In this case, the second region abuts against an expansion object such as a lesion when the balloon is inflated, thereby suppressing the balloon from slipping. In addition, the second region is only provided in a portion of the axial direction of the balloon, and the first region with a small surface roughness is formed otherwise. In this case, compared with a case where the second region is provided in the entire axial direction of the balloon, the sliding resistance when the balloon is introduced into a tube such as a blood vessel can be reduced. Thus, the reduction in the permeability of the balloon in the tube can be suppressed, and the balloon from slipping when the balloon is inflated can be suppressed.

[0015] The second disclosed balloon catheter is based on the first disclosed one, wherein the balloon comprises: a straight tube portion, which has the largest diameter when expanded; and a pair of tapered portions, which are arranged on both sides of the straight tube portion in the axial direction and reduce in diameter toward a side away from the straight tube portion, and the second area is formed on the outer surface of the tapered portion.

[0016] When the lesion is expanded by the tapered portion of the balloon, the tapered portion is in contact with the lesion obliquely, and therefore, as a reaction, the tapered portion is pressed obliquely by the lesion, and the balloon may slip in the axial direction. In this regard, in the second disclosure, a second area with a large surface roughness is formed on the outer surface of the tapered portion. In this case, the second area of ​​the tapered portion is in contact with the lesion when the balloon is expanded, thereby preventing the tapered portion from slipping in the axial direction, and further preventing the balloon from slipping in the axial direction.

[0017] The balloon catheter of the third disclosure is based on 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.

[0018] However, when the lesion formed in a blood vessel or the like is large, the inside of the lesion becomes narrow, so it may be impossible to introduce the straight tube portion of the balloon into the inside of the lesion. Therefore, in this case, it is considered to first introduce the tapered portion of the front end side of the balloon with a relatively small diameter into the inside of the lesion, and inflate the balloon in this introduced state. In this case, the lesion is expanded by the tapered portion of the front end side.

[0019] However, when the lesion is expanded in this way, the tapered portion on the front end side is pressed from the lesion to the base end side (proximal side), and the tapered portion on the front end side may slip toward the base end side. Therefore, in view of this point, in the third disclosure, a second area is formed on the outer surface of the tapered portion on the front end side. Thus, when the lesion is expanded as described above, the tapered portion on the front end side can be prevented from slipping toward the base end side, and further, the balloon can be prevented from slipping toward the base end side.

[0020] The fourth disclosed balloon catheter is based on the third disclosed balloon catheter, which includes a catheter body having the balloon arranged on the front end side, the balloon having a front end side branch tube portion, the front end side branch tube portion is arranged on the side opposite to the straight tube portion across the tapered portion on the front end side, and is connected to the catheter body, and the second area is formed on the outer surface of the front end side branch tube portion.

[0021] In the case where the inner side of the lesion is narrowed, it is considered to introduce the front-end side branch tube portion together with the tapered portion on the front-end side into the inner side of the lesion portion, and expand the balloon in this introduced state. In this regard, in the fourth disclosure, in addition to the tapered portion on the front-end side, a second area is also formed on the outer surface of the front-end side branch tube portion. Thereby, when the balloon is expanded as described above, it is possible to further suppress the balloon from slipping toward the base end side.

[0022] The balloon catheter of the fifth disclosure is based on any one of the second to fourth disclosures, wherein the first region is formed on the outer surface of the straight tube portion.

[0023] The straight tube portion is the part with the largest diameter in the balloon, so it is easy to slide against the tube wall when the balloon is introduced into the tube. In this regard, in the fifth disclosure, since a first area with a small surface roughness is formed on the outer surface of the straight tube portion, the sliding resistance when the balloon is introduced into the tube can be appropriately suppressed. As a result, the passability of the balloon can be appropriately suppressed.

[0024] A sixth disclosed balloon catheter is the one disclosed in the fifth disclosure, wherein the surface roughness of the second region of the tapered portion decreases as it approaches the straight tube portion.

[0025] In the tapered portion, the diameter of the portion on the straight tube side is relatively large. Therefore, it is considered that when the balloon is introduced into the tube, the portion on the straight tube side of the tapered portion is easy to slide with the tube wall. Therefore, in view of this point, in the sixth disclosure, the surface roughness of the second area of ​​the tapered portion is reduced as it approaches the straight tube. In this case, when the balloon is introduced into the tube, the sliding resistance of the portion on the straight tube side of the tapered portion can be reduced. Therefore, the sliding resistance when the balloon is introduced into the tube can be further reduced.

[0026] The seventh disclosed balloon catheter is based on the second disclosed balloon catheter, which includes a catheter body having the balloon arranged on the front end side, the balloon having a branch tube portion, the branch tube portion being arranged on the side opposite to the straight tube portion across the tapered portion forming the second area, and being joined to the catheter body, and the second area being formed on the outer surface of the branch tube portion.

[0027] In the case where the inner side of the lesion is narrowed, it is considered to introduce the branch tube portion together with the tapered portion into the inner side of the lesion portion. In this regard, in the seventh disclosure, in addition to the outer surface of the tapered portion, a second area is also formed on the outer surface of the branch tube portion. This can further suppress the balloon from slipping when the balloon is inflated.

[0028] The balloon catheter of the eighth disclosure is based on any one of the first to fourth disclosures, wherein the second region is provided over the entire circumferential region of the balloon.

[0029] According to the eighth disclosure, since the second region is provided over the entire circumferential region of the balloon, the second region can reliably contact the expansion target such as the lesion when the balloon is inflated. Thus, it is possible to reliably suppress the balloon from slipping when the balloon is inflated.

[0030] The ninth disclosed balloon catheter is based on the second disclosed, wherein an inner protrusion is provided on the tapered portion, the inner protrusion protruding from the inner surface of the tapered portion and extending along the inner surface in the axial direction, an area on the outer surface of the tapered portion on which 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 including the overlapping area on the outer surface of the tapered portion on which the inner protrusion is provided.

[0031] According to the ninth disclosure, the tapered portion of the balloon is provided with an inner protrusion that protrudes from the inner surface of the tapered portion and extends in the axial direction. In this case, the rigidity of the portion of the tapered portion provided with the inner protrusion becomes higher, so when the balloon is inflated and the lesion is expanded through the tapered portion, the above-mentioned portion of the tapered portion can be firmly in contact with the lesion. Thus, when the lesion is expanded through the tapered portion, the tapered portion can be made difficult to be pushed back from the lesion.

[0032] In addition, when the lesion is expanded by the tapered portion, the overlapping region of the outer surface of the tapered portion that overlaps with the inner protrusion in the thickness direction of the tapered portion is firmly in contact with the lesion. In this regard, in the ninth disclosure, the second region is formed in a range of the outer surface of the tapered portion that includes the overlapping region. Thus, the second region can be firmly in contact with the lesion in the overlapping region. Therefore, it is possible to appropriately suppress the slippage of the balloon.

[0033] The balloon catheter of the tenth disclosure is based on the ninth disclosure, wherein the surface roughness of a predetermined area of ​​the second region formed in the overlapping area is greater than the surface roughness of other areas.

[0034] According to the tenth disclosure, the surface roughness of a predetermined area formed in the overlap region in the second region is greater than that of other areas. In this case, the surface roughness of the overlap region that is in firm contact with the lesion becomes greater, thereby improving the effect of preventing the balloon from slipping.

[0035] The eleventh disclosed balloon catheter is based on the ninth or tenth disclosed invention, wherein the straight tube portion is provided with an outer protrusion protruding from the outer surface of the straight tube portion and extending in the axial direction, and the inner protrusion and the outer protrusion are arranged at the same position in the circumferential direction of the balloon.

[0036] According to the eleventh disclosure, since the outer protrusion is provided on the straight tube portion of the balloon, when the balloon is inflated, an incision is formed at the lesion portion by the outer protrusion, and the lesion portion can be easily expanded by using the incision as an opportunity. In addition, the inner protrusion of the tapered portion and the outer protrusion of the straight tube portion are arranged at the same position in the circumferential direction of the balloon. In this case, the inner protrusion and the outer protrusion with higher rigidity are arranged in the axial direction, so that when the lesion portion is expanded by the tapered portion, the tapered portion can be further difficult to be pushed back from the lesion portion.

[0037] The twelfth disclosed method for manufacturing a balloon catheter is the fifth disclosed method for manufacturing a balloon catheter, wherein the balloon is manufactured using a mold having an internal space forming the balloon, the internal space having a first space portion forming the straight tube portion and a second space portion forming the tapered portion, the inner wall surface of the mold forming the internal space including a first face portion forming the first space portion and a second face portion forming the second space portion, the surface roughness of the second face portion being greater than the surface roughness of the first face portion, the manufacturing method comprising: a configuration step, wherein a tubular parison which will serve as a basis for the balloon is configured in the internal space; and an expansion step, wherein the parison is expanded in the internal space, in which the first region is formed on the outer surface of the straight tube portion by bringing the outer peripheral surface of the expanded parison into close contact with the first face portion, and the second region is formed on the outer surface of the tapered portion by bringing the outer peripheral surface of the expanded parison into close contact with the second face portion.

[0038] According to the twelfth disclosure, when the parison expands 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 the parison is expanded to form a balloon, there is no need to perform a post-process such as cutting the outer surface of the tapered portion to form the second region. Therefore, the balloon catheter of the fifth disclosure can be manufactured relatively easily.

[0039] The thirteenth disclosed balloon catheter is applied to such a balloon catheter based on the twelfth disclosed invention: an outer protrusion protruding from the outer surface of the straight tube portion and extending in the axial direction is provided on the straight tube portion, an inner protrusion protruding from the inner surface of the conical portion and extending along the inner surface in the axial direction is provided on the tapered portion, a protrusion protruding from the outer peripheral surface of the parison and extending in the longitudinal direction of the parison is provided on the parison, a groove extending in the longitudinal direction of the internal space is formed on the first face portion, and the groove is not formed on the second face portion, in the expansion process, the outer protrusion is formed by allowing the protrusion of the expanded parison to enter the groove, in the expansion process, the protrusion of the expanded parison is pressed against the second face portion to be flattened, so that a portion of the parison along the protrusion protrudes toward the inner peripheral side to form the inner protrusion, and the second region is formed by the surface that is in close contact with the second face portion during the flattening.

[0040] According to the thirteenth disclosure, the parison provided with the protrusion expands in the internal space of the mold, thereby forming an outer protrusion on the straight tube portion of the balloon and an inner protrusion on the tapered portion. Specifically, the inner protrusion is formed by pressing the protrusion of the expanded parison against the second face portion of the mold. In addition, when the protrusion is flattened, the surface that is in close contact with the second face portion forms a second area. In this case, the overlapping area on the outer surface of the tapered portion that overlaps with the inner protrusion in the thickness direction of the tapered portion forms a second area with a large surface roughness. Thus, the balloon catheter of the ninth disclosure described above can be manufactured relatively easily.

[0041] The fourteenth disclosed method for manufacturing a balloon is based on the thirteenth disclosed method, wherein the second surface portion surrounding the second space portion becomes a protruding surface portion that protrudes inwardly in a circumferential direction, and in the inflation step, the protrusion is pressed against the protruding surface portion to flatten it.

[0042] 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 circumference, so that the protruding portion and the second surface portion (protruding surface portion) can be firmly attached to each other. As a result, the surface roughness of the second area formed in the overlapping area can be further increased. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The above-mentioned object and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description with reference to the accompanying drawings.

[0044] Figure 1 It is a schematic overall side view showing the structure of the balloon catheter in the first embodiment.

[0045] Figure 2 (a) is a side view showing the structure of the balloon and its surroundings, and (b) is a side view showing the balloon and its surroundings, showing the balloon and the outer tube in a longitudinal cross-sectional state.

[0046] Figure 3 It is a cross-sectional view showing the structure of a mold, and also showing the parison arranged inside the mold.

[0047] Figure 4 This is an explanatory diagram for explaining how to use a balloon catheter.

[0048] Figure 5 It is a side view showing the structure of the balloon and its surroundings in the second embodiment.

[0049] Figure 6 (a) is a side view showing the structure of the balloon and its periphery in the third embodiment, (b) is a cross-sectional view taken along line AA of (a), (c) is a cross-sectional view taken along line BB of (a), and (d) is a cross-sectional view taken along line CC of (a).

[0050] Figure 7 It is a side view showing the balloon and its surroundings, showing the balloon and the outer tube in a longitudinal cross-section.

[0051] Figure 8 It is a perspective view showing a parison.

[0052] Fig. 9 (a) is a cross-sectional view showing the structure of the mold, (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).

[0053] Fig.10 is a cross-sectional view showing the state of the parison expanding in the internal space of the mold, (a) is a Fig. 9 (a) is the DD line cross section observation, (b) is the Fig. 9 (a) is the EE line cross section observation, (c) is the Fig. 9 (a) FF line cross-sectional observation diagram. DETAILED DESCRIPTION

[0054] [First embodiment]

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

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

[0057] The catheter body 11 includes an outer tube 15 and an inner tube 16 that penetrates the inner portion of the outer tube 15. The outer tube 15 is formed into a tubular shape by a resin material and has an inner cavity 15a extending in the entire axial direction (see Figure 2 (b)). The base end of the outer tube 15 is joined to the sleeve 12, and the front end of the outer tube 15 is joined to the balloon 13. In addition, the inner cavity 15a of the outer tube 15 is connected to the inside of the sleeve 12 and to the inside of the balloon 13. The inner cavity 15a of the outer tube 15 serves as a fluid lumen through which the compressed fluid flows when the balloon 13 is expanded or deflated.

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

[0059] The inner tube 16 is formed of a resin material into a tubular shape and has an inner cavity 16a extending in the entire axial direction (see Figure 2 (b)). The base end of the inner tube 16 is joined to the middle position of the outer tube 15 in the axial direction. In addition, a portion of the front end side of the inner tube 16 extends further to the front end side than the outer tube 15, and the extended portion penetrates the inside of the balloon 13. Moreover, the vicinity of the front end of the inner tube 16 is joined to the front end of the balloon 13.

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

[0061] Next, based on Figure 2 The balloon 13 and its peripheral structure will be described. Figure 2 (a) is a side view showing the structure of the balloon 13 and its surroundings. Figure 2 (b) is a side view showing the structure of the balloon 13 and its surroundings, showing the balloon 13 and the outer tube 15 in a longitudinal cross-section. Figure 2 (a) and (b) show the inflated state of the balloon 13 .

[0062] The balloon 13 is formed of a thermoplastic resin material, for example, a polyamide elastomer. Figure 2 As shown in (a) and (b) of FIG. 1 , the balloon 13 is formed as a whole into a cylindrical (tubular) shape having a circular cross section. Specifically, the balloon 13 has a base end side branch tube portion 13a, a base end side tapered portion 13b, a straight tube portion 13c, a front end side tapered portion 13d, and a front end side branch tube portion 13e, and these portions 13a to 13e are arranged in the above order from the base end side toward the front end side.

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

[0064] When compressed fluid is supplied to the inside of the balloon 13 through the inner cavity 15a of the outer tube 15, the balloon 13 is in an expanded state. On the other hand, when negative pressure is applied to the inner cavity 15a of the outer tube 15 and the compressed fluid is discharged from the inside of the balloon 13, the balloon 13 is in a contracted state. Although not shown in the figure, the balloon 13 has a plurality of blades formed in a contracted state. These blades are arranged at a predetermined interval in the circumferential direction of the balloon 13, and when the balloon 13 is in a contracted state, they are folded along the circumferential direction of the balloon 13 and are in a state of being wound around the inner tube 16.

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

[0066] Here, in the present balloon catheter 10, a plurality of regions having different surface roughness are formed on the outer surface of the balloon 13. Therefore, these regions will be described below.

[0067] like Figure 2 As shown in (a), a first region 21 with a small surface roughness and a second region 22 with a larger surface roughness than the first region 21 are formed on the outer surface of the balloon 13. The first region 21 and the second region 22 are arranged in the axial direction of the balloon 13. Figure 2 In (a), the second region 22 is indicated by hatching.

[0068] The first region 21 is formed on the outer surface of the straight tube portion 13c of the balloon 13, and more specifically, is formed on the entire outer surface of the straight tube portion 13c. The surface roughness of the first region 21 is constant throughout the entire region of the first region 21.

[0069] The second region 22 is formed on each outer surface of the base end side branch tube portion 13a, the base end side tapered portion 13b, the front end side tapered portion 13d, and the front end side branch tube portion 13e of the balloon 13. In detail, the second region 22 is formed in the entire area of ​​the outer surface of the above-mentioned parts 13a, 13b, 13d, and 13e of the balloon 13. Therefore, the second region 22 is formed in all areas of the outer surface of the balloon 13 except the area (the outer surface of the straight tube portion 13c) where the first region 21 is formed. In addition, the surface roughness of the second region 22 of the above-mentioned parts 13a, 13b, 13d, and 13e is the same size. In addition, the surface roughness of the second region 22 of the above-mentioned parts 13a, 13b, 13d, and 13e is constant throughout its entire area.

[0070] It should be noted that the surface roughness of the second region 22 of each of the above-mentioned parts 13a, 13b, 13d, and 13e in the balloon 13 does not necessarily need to be the same. For example, the surface roughness of the second region 22 of each tapered part 13b, 13d can also be greater or less than the surface roughness of the second region 22 of each branch part 13a, 13e.

[0071] In addition, in this specification, "surface roughness" means the arithmetic mean roughness Ra specified in JIS B0601: 2001. The arithmetic mean roughness Ra is measured in accordance with JIS B0633: 2001, and the measurement is performed using a measuring machine specified in JIS B0651: 2001.

[0072] Next, the method for manufacturing the balloon 13 is described. The balloon 13 is manufactured using the mold 30. Figure 3 The structure of the mold 30 will be described. Figure 3 is a cross-sectional view showing the structure of the mold 30. It should be noted that Figure 3 In FIG. 1 , a parison 39 disposed inside the mold 30 is also shown.

[0073] like Figure 3 As shown, the mold 30 is formed into a rectangular parallelepiped, and has an internal space 31 therein for forming the balloon 13. The internal space 31 is an elongated space extending in the length 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 (specifically, the shape of the cross section orthogonal to the length direction of the internal space 31) is circular in the entire area in the length direction.

[0074] The internal space 31 includes a space 31a forming the proximal side branch tube portion 13a of the balloon 13, a space 31b forming the proximal side tapered portion 13b (equivalent to the second space), a space 31c forming the straight tube portion 13c (equivalent to the first space), a space 31d forming the distal side tapered portion 13d (equivalent to the second space), and a space 31e forming the distal side branch tube portion 13e. Each of these space portions 31a to 31e has a shape corresponding to each portion 13a to 13e of the balloon 13.

[0075] The mold 30 is formed by combining a plurality of mold components. These mold components include a plurality of mold components 32 to 34 that form an internal space 31. The mold component 32 of each mold component 32 to 34 forms a space portion 31c for the straight tube portion 13c. In addition, the mold component 33 forms a space portion 31b for the base end tapered portion 13b and a space portion 31a for the base end branch tube portion 13a. In addition, the mold component 34 forms a space portion 31d for the front end tapered portion 13d and a space portion 31e for the front end branch tube portion 13e. It should be noted that the mold 30 does not necessarily need to be composed of a plurality of mold components, but may also be composed of a single mold component.

[0076] The mold 30 has an inner wall surface 37 forming the internal space 31. The inner wall surface 37 includes an inner wall surface 37a of the space portion 31a for forming the proximal side branch pipe portion 13a, an inner wall surface 37b (equivalent to the second surface portion) of the space portion 31b for forming the proximal side tapered portion 13b, an inner wall surface 37c (equivalent to the first surface portion) of the space portion 31c for forming the straight pipe portion 13c, an inner wall surface 37d (equivalent to the second surface portion) of the space portion 31d for forming the distal side tapered portion 13d, and an inner wall surface 37e of the space portion 31e for forming the distal side branch pipe portion 13e. The surface roughness of the inner wall surface 37c among the inner wall surfaces 37a to 37e is smaller, and the surface roughness of each of the inner wall surfaces 37a, 37b, 37d, and 37e is greater than the surface roughness of the inner wall surface 37c. In addition, the surface roughness of each of the inner wall surfaces 37a, 37b, 37d, and 37e is the same. It should be noted that in Figure 3 In the figure, each inner wall surface 37a, 37b, 37d, 37e is indicated by hatching.

[0077] Next, a method for manufacturing the balloon 13 using the mold 30 is described. When manufacturing the balloon 13, first, a preparation step is performed to prepare the mold 30 and a parison 39 serving as a base of the balloon 13. The parison 39 is formed into a circular tube shape from a resin material, for example, by extrusion molding.

[0078] Next, a placement step is performed to place the parison 39 in the internal space 31 of the mold 30 . In this step, the parison 39 is placed in the internal space 31 with the longitudinal direction of the parison 39 facing the longitudinal direction of the internal space 31 .

[0079] Next, an expansion process is performed to heat and expand the parison 39 in the internal space 31 of the mold 30. In this process, the parison 39 is expanded by introducing a fluid such as nitrogen into the inside of the parison 39. As a result, an expanded parison body including a portion in the shape of the balloon 13 is formed, in other words, an expanded parison body including the portions 13a to 13e constituting the balloon 13 is formed. It should be noted that a stretching process may be performed before the expansion process to extend the parison 39 in the longitudinal direction. In addition, the expansion process may also be referred to as a blow molding process for performing blow molding.

[0080] In the expansion step, the first region 21 is formed on the outer surface of the straight tube portion 13c by bringing the outer peripheral surface of the expanded parison 39 into close contact with the inner wall surface 37c of the mold 30 (mold member 32). In addition, the second region 22 is formed on the outer surfaces of the base end tapered portion 13b and the base end branch tube portion 13a by bringing the outer peripheral surface of the expanded parison 39 into close contact with the inner wall surfaces 37a and 37b of the mold 30 (mold member 33). In addition, the second region 22 is formed on the outer surfaces of the front end tapered portion 13d and the front end branch tube portion 13e by bringing the outer peripheral surface of the expanded parison 39 into close contact with the inner wall surfaces 37d and 37e of the mold 30 (mold member 34).

[0081] After the expansion step, a cutting step is performed to cut off the remaining portions at both ends of the expanded parison body. Thus, the balloon 13 is formed, and the manufacture of the balloon 13 is completed.

[0082] Then, as post-processes, a process of joining the balloon 13 to the catheter body 11 and a process of joining the hub 12 to the catheter body 11 are performed. Thus, a series of manufacturing operations are completed.

[0083] Next, the method of using the balloon catheter 10 is described. Here, the steps of using the balloon catheter 10 to dilate the lesion formed in the blood vessel are described. Figure 4 This is an explanatory diagram for explaining this step.

[0084] First, the guide catheter is inserted into the sheath introducer inserted into the blood vessel, and the front end opening of the guide catheter is introduced into the coronary artery entrance. Next, the guide wire G is inserted into the guide catheter, and the inserted guide wire G is introduced from the coronary artery entrance to the peripheral part through the lesion.

[0085] Next, the balloon catheter 10 is introduced into the guide catheter along the guide wire G. After the introduction, the balloon 13 is introduced toward the lesion 38 while applying a push-pull operation. During the introduction, the balloon 13 is brought into a deflated state.

[0086] exist Figure 4 In the example of (a), the lesion 38 generated in the blood vessel is relatively large. Therefore, the inside of the lesion 38 is significantly narrowed. In this case, it is assumed that the balloon 13 cannot be smoothly introduced into the inside of the lesion 38, for example, it is assumed 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, first, Figure 4 As shown in (a), the tapered front end portion 13d and the front end branch portion 13e of the balloon 13 are introduced into the inner side of the lesion 38. Then, the balloon 13 is inflated in this state. Figure 4 As shown in (b), the lesion 38 is expanded by the expanded distal tapered portion 13d.

[0087] Here, when the lesion 38 is expanded by the front end tapered portion 13d, the front end tapered portion 13d is in contact with the lesion 38 obliquely, so as a reaction, the front end tapered portion 13d is pressed obliquely by the lesion 38, and the balloon 13 may slip toward the base end side (proximal end side). In this regard, in the balloon 13 of the present embodiment, since the second region 22 with a large surface roughness is formed on the outer surface of the front end tapered portion 13d, the second region 22 is in contact with the lesion 38, so that the front end tapered portion 13d can be prevented from slipping toward the base end side, and the balloon 13 can be prevented from slipping toward the base end side.

[0088] In addition, since the second region 22 is also formed on the outer peripheral surface of the distal side branch tube portion 13e, the second region 22 of the distal side branch tube portion 13e introduced into the inner side of the lesion portion 38 contacts the lesion portion 38. Therefore, it is possible to further suppress the balloon 13 from slipping toward the base end when the lesion portion 38 is expanded by the distal side tapered portion 13d.

[0089] After the lesion 38 is expanded by the front end tapered portion 13d, Figure 4 As shown in (c), the balloon 13 is put into a contracted state. Furthermore, in this contracted state, the balloon 13 is further moved toward the front end side (distal end side), and the front end side tapered portion 13d and the front end side branch tube portion 13e of the balloon 13 are introduced into the inner side of the unexpanded portion of the lesion 38 that has not yet been expanded. At this time, the straight tube portion 13c of the balloon 13 is arranged on the inner side of the tapered expanded portion of the lesion 38 that has been expanded by the front end side tapered portion 13d. Furthermore, in the introduced state of the balloon 13, the balloon 13 is inflated again. As a result, the unexpanded portion of the lesion 38 is expanded using the front end side tapered portion 13d in the same manner as described above (refer to Figure 4(d)). In addition, the tapered expansion portion of the lesion 38 is further expanded outward by the straight tube portion 13c.

[0090] Through such steps, the unexpanded portion of the lesion 38 is expanded sequentially from the proximal side to the distal side. Figure 4 As shown in FIG. 5 ( e ), the entire area of ​​the lesion 38 is expanded by the balloon 13 .

[0091] After the lesion 38 is expanded, the balloon 13 is deflated, and the balloon catheter 10 is pulled out of the body. Thus, a series of operations are completed.

[0092] It should be noted that the balloon catheter 10 is mainly passed through blood vessels as described above, for example, for treating blood vessels such as coronary arteries, femoral arteries, and pulmonary arteries, but can also be used in "tubes" and "body cavities" in the body such as ureters and digestive tracts other than blood vessels.

[0093] According to the structure of this embodiment described in detail above, the following excellent effects can be obtained.

[0094] Since the second region 22 with a large surface roughness is formed on the outer surface of the balloon 13, the second region 22 abuts against the lesion 38 when the balloon 13 is expanded, thereby preventing the balloon 13 from slipping. In addition, the second region 22 is provided only in a portion of the axial direction of the balloon 13, and the first region 21 with a small surface roughness is formed in the other part. In this case, compared with the case where the second region 22 is provided in the entire axial direction of the balloon 13, the sliding resistance when the balloon 13 is introduced into the blood vessel can be reduced. As a result, the decrease in the passability of the balloon 13 can be suppressed, and the balloon 13 can be suppressed from slipping when the balloon 13 is expanded.

[0095] The straight tube portion 13c is the part with the largest diameter in the balloon 13, so it is easy to slide with the tube wall when the balloon 13 is introduced into the blood vessel. In this regard, since the first area 21 with a small surface roughness is formed on the outer surface of the straight tube portion 13c, the sliding resistance when the balloon 13 is introduced into the blood vessel can be appropriately suppressed. As a result, the passability of the balloon 13 can be appropriately suppressed.

[0096] In addition to the front end tapered portion 13d, the outer surface of the base end tapered portion 13b is also formed with a second area 22. Thus, when the balloon 13 is inflated to expand the lesion through the base end tapered portion 13b, even if the base end tapered portion 13b is pressed obliquely by the lesion, the base end tapered portion 13b can be prevented from slipping toward the front end, thereby preventing the balloon 13 from slipping toward the front end.

[0097] Since the second region 22 is provided over the entire circumferential region of the balloon 13, even when the lesion 38 is formed only in a portion of the circumferential direction of the blood vessel, the second region 22 can reliably abut against the lesion 38 when the balloon 13 is inflated. Thus, the balloon 13 can be reliably prevented from slipping when the balloon 13 is inflated.

[0098] When the expansion process of expanding the parison 39 in the internal space 31 of the mold 30 is performed, 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 cutting the outer surfaces of the tapered portions 13b and 13d to form the second region 22. Therefore, the balloon 13 having the first region 21 and the second region 22 with different surface roughness can be manufactured relatively easily.

[0099] [Second embodiment]

[0100] Next, the second embodiment is described. In this embodiment, the surface roughness of the second region formed on the outer surface of each tapered portion 13b, 13d of the balloon 13 changes in the axial direction of the balloon 13. This point is different from the first embodiment described above in this embodiment, and the difference is described below. It should be noted that, Figure 5 It is a side view showing the balloon 13 and the surrounding structure in this embodiment.

[0101] like Figure 5 As shown, in the balloon 13 of this embodiment, a first region 21 is formed on the outer surface of the straight tube portion 13c, and a second region 22 is formed on the outer surface of each of the base side branch tube portion 13a and the front side branch tube portion 13e. These regions 21 and 22 have the same structure as the first embodiment, so their description is omitted here. It should be noted that in Figure 5 In FIG. 1 , the second region 22 is indicated by being shaded.

[0102] In the balloon 13 of the present embodiment, the second region 42 having a surface roughness greater than that of the first region 21 is formed on each outer surface of the base end tapered portion 13b and the front end tapered portion 13d. Figure 5In the figure, each of the second regions 42 is indicated by dotted hatching. The second region 42b of the base end tapered portion 13b in each second region 42 is formed over the entire outer surface of the base end tapered portion 13b. The surface roughness of the second region 42b gradually decreases from the base end side toward the front end side. The surface roughness of the second region 42b is greater than the surface roughness of the first region 21 of the straight tube portion 13c in the entire region. In addition, the surface roughness of the second region 42b is less than the surface roughness of the second region 22 of the base end branch tube portion 13a in the entire region.

[0103] The surface roughness of the second region 42d of the distal tapered portion 13d gradually decreases from the distal end side toward the proximal end side. The second region 42d is formed over the entire outer surface of the distal tapered portion 13d. The second region 42d has a larger surface roughness than the first region 21 of the straight tube portion 13c over the entire region. In addition, the second region 42d has a smaller surface roughness than the second region 22 of the distal branch tube portion 13e over the entire region.

[0104] As described above, the surface roughness of the second region 42b, 42d of each tapered portion 13b, 13d gradually decreases as it approaches the straight tube portion 13c. In other words, the surface roughness of the second region 42b, 42d of each tapered portion 13b, 13d gradually increases as it moves away from the straight tube portion 13c.

[0105] The balloon 13 of the present embodiment is manufactured in the same steps as the first embodiment. As described above, in the balloon 13 of the present embodiment, the surface roughness of the second regions 42b, 42d of the tapered portions 13b, 13d is different from that of the balloon 13 of the first embodiment. Therefore, the mold 30 (see Figure 3 ), use a mold whose surface roughness of each inner wall surface 37b, 37d corresponds to the surface roughness of the second area 42b, 42d.

[0106] According to the structure of this embodiment described in detail above, the following excellent effects can be obtained.

[0107] In the balloon 13, a first region 21 with a small surface roughness is formed on the outer surface of the straight tube portion 13c, a second region 42 with a large surface roughness is formed on the outer surface of each tapered portion 13b, 13d, and a second region 22 with a large surface roughness is formed on the outer surface of each branch tube portion 13a, 13e. Thus, the same effect as the first embodiment can be obtained.

[0108] In the tapered portions 13b and 13d, the diameter of the portion on the straight tube portion 13c side is relatively large. Therefore, it is considered that when the balloon 13 is introduced into the blood vessel, the portion on the straight tube portion 13c side is easy to slide with the tube wall. Therefore, in the above-mentioned embodiment, in view of this point, the surface roughness of the second area 42b, 42d of each tapered portion 13b, 13d is reduced as it approaches the straight tube portion 13c. In this case, when the balloon 13 is introduced into the blood vessel, the sliding resistance of the portion on the straight tube portion 13c side of each tapered portion 13b, 13d can be reduced. Therefore, the sliding resistance when the balloon 13 is introduced into the blood vessel can be further reduced.

[0109] In addition, in the front end tapered portion 13d, the diameter of the portion away from the straight tube portion 13c (that is, the portion on the front end side) is relatively small. Therefore, the portion away from the straight tube portion 13c is easily introduced into the narrowed portion. In this regard, in the above-mentioned embodiment, the surface roughness of the second area 42d of the front end tapered portion 13d increases as it moves away from the straight tube portion 13c. Therefore, when the front end tapered portion 13d is introduced into the narrowed portion to inflate the balloon 13, the front end tapered portion 13d can be appropriately suppressed from slipping toward the base end side, and the balloon 13 can be appropriately suppressed from slipping toward the base end side.

[0110] [Third Embodiment]

[0111] Next, the third embodiment is described. In this embodiment, linear protrusions are provided on the outer surface and the inner surface of the balloon 13. Figure 6 and Figure 7 These protrusions will be described. Figure 6 (a) is a side view showing the structure of the balloon 13 and its surroundings in this embodiment, (b) is a cross-sectional view taken along line AA of (a), (c) is a cross-sectional view taken along line BB of (a), and (d) is a cross-sectional view taken along line CC of (a). Figure 6 (a) to (d) of FIG. 1 show the expanded state of the balloon 13. Figure 7 It is a side view showing the balloon 13 and its surroundings, and shows the balloon 13 and the outer tube 15 in a longitudinal cross-sectional state.

[0112] like Figure 6 (a) to (d) and Figure 7 As shown, in the balloon 13, the straight tube portion 13c is provided with an outer protrusion 51, the base end tapered portion 13b is provided with an inner protrusion 52, and the front end tapered portion 13d is provided with an inner protrusion 53. These protrusions 51 to 53 are formed integrally with the balloon 13.

[0113] The outer protrusion 51 protrudes from the outer surface of the straight tube portion 13c and extends along the outer surface of the straight tube portion 13c in the axial direction of the balloon 13. In detail, the outer protrusion 51 extends over the entire area in the axial direction of the straight tube portion 13c. A plurality of (specifically, three) outer protrusions 51 are arranged at predetermined intervals (specifically, at equal intervals) in the circumferential direction of the balloon 13. In addition, the cross section of each outer protrusion 51 (specifically, a cross section orthogonal to the length direction of the outer protrusion 51) is in the shape of a mountain protruding radially outward of the balloon 13, specifically, in the shape of a triangle.

[0114] When the balloon 13 is inflated and the lesion is expanded, the outer protrusion 51 forms an incision in the lesion. In the present balloon catheter 10, the incision is formed in the lesion by the outer protrusion 51, so that the lesion can be easily expanded by using the incision as an opportunity. Therefore, the present balloon catheter 10 becomes a balloon catheter with a scoring function.

[0115] The inner protrusion 52 of the base-side tapered portion 13b protrudes from the inner surface of the base-side tapered portion 13b and extends in the axial direction of the balloon 13 along the inner surface of the base-side tapered portion 13b. In detail, the inner protrusion 52 extends in the entire area in the axial direction of the base-side tapered portion 13b. A plurality of (three in the present embodiment) inner protrusions 52 are arranged at prescribed intervals (in detail, at equal intervals) in the circumferential direction of the balloon 13. Each of these inner protrusions 52 is arranged in the same position as each outer protrusion 51 in the circumferential direction of the balloon 13. In addition, the cross-section of each inner protrusion 52 (in detail, a cross-section orthogonal to the length direction of the inner protrusion 52) is in the shape of a semicircle convex toward the inner side of the balloon 13.

[0116] The inner protrusion 53 of the front end side tapered portion 13d protrudes from the inner surface of the front end side tapered portion 13d and extends in the axial direction of the balloon 13 along the inner surface of the front end side tapered portion 13d. In detail, the inner protrusion 53 extends in the entire area in the axial direction of the front end side tapered portion 13d. A plurality of inner protrusions 53 (three in the present embodiment) are arranged at prescribed intervals (equidistant intervals, in detail) in the circumferential direction of the balloon 13. Each of these inner protrusions 53 is arranged at the same position as each outer protrusion 51 in the circumferential direction of the balloon 13. In addition, the cross section of each inner protrusion 53 (in detail, a cross section orthogonal to the length direction of the inner protrusion 53) is in the shape of a semicircle convex toward the inner side of the balloon 13.

[0117] The outer surface of the balloon 13 includes a first region 55 having a small surface roughness and second regions 56 to 59 having a larger surface roughness than the first region 55. Figure 6(a) of these regions 55 to 59 are described. Figure 6 In (a), each of the second regions 56 to 59 is indicated by hatching.

[0118] like Figure 6 As shown in (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 proximal side branch tube portion 13a, a second region 57 is formed on the outer surface of the distal side branch tube portion 13e, a second region 58 is formed on the outer surface of the proximal 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 on the entire outer surface of the straight tube portion 13c. The surface roughness of the first region 55 is constant throughout the entire region of the first region 55.

[0119] The second region 56 of the base side branch pipe part 13a is formed on the entire outer surface of the base side branch pipe part 13a. In addition, the second region 57 of the front side branch pipe part 13e is formed on the entire outer surface of the front side branch pipe part 13e. The surface roughness of each of these second regions 56 and 57 is the same. In addition, the surface roughness of each second region 56 and 57 is constant throughout its entire area.

[0120] The second area 58 of the base end tapered portion 13b is formed over the entire outer surface of the base end tapered portion 13b. The area of ​​the outer surface of the base end tapered portion 13b that overlaps with the inner protrusion 52 in the thickness direction of the base end tapered portion 13b is the overlapping area 45. Specifically, the overlapping area 45 is an area that overlaps with the inner protrusion 52 in the thickness direction on the side opposite to the protruding side of the inner protrusion 52. The outer surface of the base end tapered portion 13b includes the overlapping areas 45 of each inner protrusion 52. Each overlapping area 45 extends elongatedly along the inner protrusion 52.

[0121] The second region 58 of the base end tapered portion 13b includes a plurality of (specifically, three) second regions 58a formed in each overlapping region 45 on the outer surface of the base end tapered portion 13b and a second region 58b formed in a region other than the overlapping region 45. The surface roughness of each second region 58a is greater than the surface roughness of the second region 58b. In addition, the surface roughness of each second region 58a is the same size. It should be noted that the second region 58a is equivalent to the "prescribed region formed in the overlapping region", and the second region 58b is equivalent to the "other region".

[0122] The second area 59 of the front end tapered portion 13d is formed over the entire outer surface of the front end tapered portion 13d. The area of ​​the outer surface of the front end tapered portion 13d that overlaps with the inner protrusion 53 in the thickness direction of the front end tapered portion 13d is the overlapping area 46. Specifically, the overlapping area 46 is an area 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 front end tapered portion 13d includes the overlapping areas 46 of the inner protrusions 53. Each overlapping area 46 extends elongatedly along the inner protrusion 53.

[0123] The second region 59 of the front end tapered portion 13d includes a plurality of (specifically, three) second regions 59a formed in each overlapping region 46 in the outer surface of the front end 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. In addition, the surface roughness of each second region 59a is the same size. It should be noted that the second region 59a is equivalent to the "prescribed region formed in the overlapping region", and the second region 59b is equivalent to the "other region".

[0124] Next, the manufacturing method of the balloon 13 of this embodiment is described. In this embodiment, since the balloon 13 is provided with the outer protrusion 51 and the inner protrusions 52 and 53, the structure of the parison 47 and the mold 60 used to manufacture the balloon 13 is different from that of the first embodiment. Therefore, the structure of the parison 47 and the mold 60 is first described below. Figure 8 4 is a perspective view showing the parison 47. Fig. 9 (a) is a cross-sectional view showing the structure 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).

[0125] First, based on Figure 8 The structure of the parison 47 will be described. Figure 8 As shown, the parison 47 is formed of a resin material into a substantially circular tubular shape, for example, by extrusion molding. The parison 47 is provided with a plurality of (specifically, three) protrusions 48 protruding from its outer peripheral surface. The cross section of the protrusion 48 (specifically, a cross section orthogonal to the length direction of the parison 47) is in a mountain shape (specifically, a triangular shape) protruding radially outward of the parison 47. Each protrusion 48 extends along the length direction of the parison 47, and specifically extends over the entire area in the length direction of the parison 47. It should be noted that the protrusion 48 forms the outer protrusion 51 and the inner protrusions 52, 53 of the balloon 13.

[0126] Next, based on Fig. 9(a) to (d) illustrate the structure of the mold 60. Fig. 9 As shown in (a), the mold 60 has a structure substantially the same 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 along the length direction of the mold 60, and has a space portion 61a for forming the proximal side branch tube portion 13a of the balloon 13, a space portion 61b (equivalent to the second space portion) for forming the proximal side tapered portion 13b, a space portion 61c (equivalent to the first space portion) for forming the straight tube portion 13c, a space portion 61d (equivalent to the second space portion) for forming the distal side tapered portion 13d, and a space portion 61e for forming the distal side branch tube portion 13e.

[0127] The mold 60 has a plurality of mold members 62 to 64 that form an internal space 61. The mold member 62 of each mold member 62 to 64 forms a space portion 61c for the straight tube portion 13c. The mold member 63 forms a space portion 61b for the base end tapered portion 13b and a space portion 61a for the base end branch tube portion 13a. In addition, the mold member 64 forms a space portion 61d for the front end tapered portion 13d and a space portion 61e for the front end branch tube portion 13e.

[0128] The mold 60 has an inner wall surface 67 forming the internal space 61. The inner wall surface 67 includes an inner wall surface 67a of the space portion 61a for forming the proximal side branch pipe portion 13a, an inner wall surface 67b (equivalent to the second surface portion) of the space portion 61b for forming the proximal side tapered portion 13b, an inner wall surface 67c (equivalent to the first surface portion) of the space portion 61c for forming the straight pipe portion 13c, an inner wall surface 67d (equivalent to the second surface portion) of the space portion 61d for forming the distal side tapered portion 13d, and an inner wall surface 67e of the space portion 61e for forming the distal side branch pipe portion 13e. The surface roughness of the inner wall surface 67c among the inner wall surfaces 67a to 67e is smaller, and the surface roughness of each of the inner wall surfaces 67a, 67b, 67d, and 67e is greater than the surface roughness of the inner wall surface 67c. In addition, the surface roughness of each of the inner wall surfaces 67a, 67b, 67d, and 67e is the same. It should be noted that in Fig. 9 In (a), each inner wall surface 67a, 67b, 67d, 67e is indicated by hatching.

[0129] The cross-sectional shape of the internal space 61 of the mold 60 of this embodiment (in other words, the cross-sectional shape of the inner wall surface 67 ) is different for each space portion 61 a to 61 e . Therefore, the structure of each space portion 61 a to 61 e will be described below in sequence.

[0130] First, based on Fig. 9 (b) The space portion 61c for the straight pipe portion 13c is described. Fig. 9As shown in (b), the cross section of the space portion 61c for the straight tube portion 13c (specifically, the cross section orthogonal to the longitudinal direction of the internal space 61) is circular. A plurality of (specifically, three) grooves 68 are formed on the inner wall surface 67c surrounding the space portion 61c. These grooves 68 extend along the longitudinal direction of the internal space 61, and specifically extend over the entire area of ​​the inner wall surface 67c in the above-mentioned longitudinal direction. In addition, the grooves 68 are arranged at equal intervals in the circumferential direction of the inner wall surface 67c. The cross-sectional shape of each groove 68 is a triangular shape protruding toward the outer peripheral side of the space portion 61c. It should be noted that 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.

[0131] Then, except Fig. 9 In addition to (a), based on Fig. 9 (c) The space portion 61d for the front end tapered portion 13d is described. Fig. 9 As shown in (a), the inner wall surface 67d of the space 61d surrounding the distal tapered portion 13d is an inclined surface inclined with respect to the axial direction of the internal space 61. This inclined surface (tapered surface) is formed by the inclination of the outer surface of the distal tapered portion 13d.

[0132] like Fig. 9 As shown in (c), the cross-section of the space portion 61d is non-circular. A portion of the circumferential direction of the inner wall surface 67d surrounding the space portion 61d becomes a protruding surface portion 71 that protrudes toward the inner circumferential side of the inner wall surface 67d. The protruding surface portion 71 extends in the axial direction of the internal space 61 along the inclination of the inner wall surface 67d and is flat. In detail, the protruding surface portion 71 extends over the entire area in the axial direction of the inner wall surface 67d. In addition, a plurality of (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).

[0133] The portion of the inner wall surface 67 d connecting the adjacent extended surface portions 71 is an arcuate surface portion 72 convex to the outer peripheral side of the inner wall surface 67 d . A plurality of (specifically, three) arcuate surface portions 72 are provided for the adjacent extended surface portions 71 .

[0134] The surface roughness of the inner wall surface 67 d is greater than that of the inner wall surface 67 c. The surface roughness of the inner wall surface 67 d is constant over the entire region of the inner wall surface 67 d including the protruding surface portion 71 and the arc surface portion 72 .

[0135] Next, the space portion 61b for the base end tapered portion 13b will be described. Fig. 9As shown in (a), the inner wall surface 67b of the space 61b surrounding the proximal tapered portion 13b is an inclined surface inclined with respect to the axial direction of the internal space 61. This inclined surface (tapered surface) is formed by the inclination of the outer surface of the proximal tapered portion 13b.

[0136] Although not shown in the figure, the space portion 61b has the same cross-sectional shape as the space portion 61d for the front end tapered portion 13d. A portion of the inner wall surface 67b surrounding the space portion 61b becomes a protruding surface portion 73 that protrudes toward the inner circumference. The protruding surface portion 73 extends in the axial direction of the internal space 61 along the inclination of the inner wall surface 67b and is flat. In detail, the protruding surface portion 73 extends over the entire area in the axial direction of the inner wall surface 67b. In addition, a plurality of (specifically, three) protruding surface portions 73 are arranged at equal intervals on the circumference of the inner wall surface 67b. Each protruding surface portion 73 is arranged at the same position as each groove portion 68 on the circumference of the inner wall surface 67b.

[0137] The portion of the inner wall surface 67 b connecting the adjacent extended surface portions 73 is an arcuate surface portion 74 convex to the outer peripheral side of the inner wall surface 67 b . A plurality of (specifically, three) arcuate surface portions 74 are provided for the adjacent extended surface portions 73 .

[0138] The surface roughness of the inner wall surface 67 b is greater than that of the inner wall surface 67 c. The surface roughness of the inner wall surface 67 b is constant over the entire region of the inner wall surface 67 b including the protruding surface portion 73 and the arc surface portion 74 .

[0139] like Fig. 9 As shown in (d) of FIG. 1 , the cross-sectional shape of the space portion 61 e for the distal branch pipe portion 13 e is circular. Similarly, the cross-sectional shape of the space portion 61 a for the proximal branch pipe portion 13 a is also circular.

[0140] Next, a method for manufacturing the balloon 13 of the present embodiment using the above-described mold 60 will be described.

[0141] First, a preparation step of preparing the mold 60 and the parison 47 is performed. Next, a placement step of placing the parison 47 in the internal space 61 of the mold 60 is performed. In this step, the parison 47 is placed in the internal space 61 with the longitudinal direction of the parison 47 facing the longitudinal direction of the internal space 61. Thus, the parison 47 is placed in the internal space 61 across the space portions 61a to 61e.

[0142] Next, an expansion step is performed to heat and expand the parison 47 in the internal space 61 of the mold 60. This step forms an expanded parison including a portion of the shape of the balloon 13, in other words, an expanded parison including the portions 13a to 13e of the balloon 13.

[0143] Next, based on Fig.10 (a) to (c) describe the expansion step in more detail. Fig.10 is a cross-sectional view showing a state where the parison 47 is expanded in the internal space 61 of the mold 60, (a) is a cross-sectional view showing a state where the parison 47 is expanded in the internal space 61 of the mold 60, Fig. 9 (a) is the DD line cross section observation, (b) is the Fig. 9 (a) is the EE line cross section observation, (c) is the Fig. 9 (a) FF line cross-sectional observation diagram.

[0144] 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) to form the first region 55 on the outer surface of the straight tube portion 13c. Fig.10 As shown in (a) of FIG. 1 , the outer protrusions 51 are formed by causing the protrusions 48 of the parison 47 to enter the grooves 68 . That is, in this case, the protrusions 48 entering the grooves 68 become the outer protrusions 51 .

[0145] In addition, 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) to form the second region 59 on the outer surface of the front end tapered portion 13d. Fig.10 As shown in (b), the expanded protrusions 48 of the parison 47 are pressed against the extended surface portions 71 of the mold 60 to be flattened, so that the portions 78 along the protrusions 48 of the parison 47 protrude toward the inner circumference to form the inner protrusions 53. At the same time, the second regions 59a are formed on the surfaces that are in close contact with the extended surface portions 71 when the protrusions 48 are flattened. Thus, the second regions 59a are formed in the overlapped regions 46 of the front end side tapered portion 13d.

[0146] In addition, 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 the second region 58 on the outer surface of the base end tapered portion 13b. Specifically, at this time, the protrusions 48 of the expanded parison 47 are pressed against the protruding surface portions 73 of the mold 60 to be flattened, so that the portions of the parison 47 along the protrusions 48 protrude toward the inner peripheral side to form the inner protrusions 52. At the same time, the second regions 58a are formed on the surfaces that are in close contact with the protruding surface portions 73 when the protrusions 48 are flattened. Thus, the second regions 58a are formed in the overlapping regions 45 of the base end tapered portion 13b.

[0147] In addition, 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 the second region 57 on the outer surface of the distal end side branch pipe 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 the second region 56 on the outer surface of the proximal end side branch pipe portion 13a. It should be noted that, at this time, each protrusion 48 of the parison 47 is pressed against the inner wall surfaces 67a and 67e and is crushed.

[0148] After the expansion step, a cutting step is performed to cut off the remaining portions at both ends of the expanded parison body. Thus, the balloon 13 is formed, and the manufacture of the balloon 13 is completed.

[0149] Then, as post-processes, a process of joining the balloon 13 to the catheter body 11 and a process of joining the hub 12 to the catheter body 11 are performed. Thus, a series of manufacturing operations are completed.

[0150] According to the structure of this embodiment described in detail above, the following excellent effects can be obtained.

[0151] In the balloon 13, a first region 55 with a small surface roughness is formed on the outer surface of the straight tube portion 13c, and second regions 56 to 59 with a large surface roughness are formed on the outer surfaces of the tapered portions 13b, 13d and the branch tube portions 13a, 13e. Thus, the same effects as those of the first embodiment can be obtained.

[0152] The tapered portions 13b and 13d of the balloon 13 are provided with inner protrusions 52 and 53 that protrude from the inner surface thereof and extend in the axial direction. In this case, the rigidity of the portion of the tapered portions 13b and 13d provided with the inner protrusions 52 and 53 is increased, so when the balloon 13 is inflated and the lesion 38 is expanded by the tapered portions 13b and 13d, the above-mentioned portion of the tapered portions 13b and 13d can be firmly in contact with the lesion 38. Thus, when the lesion 38 is expanded by the tapered portions 13b and 13d, the tapered portions 13b and 13d can be made less likely to be pushed back from the lesion 38.

[0153] In addition, when the lesion 38 is expanded by the tapered portions 13b and 13d, the overlapping regions 45 and 46 of the outer surfaces of the tapered portions 13b and 13d, which overlap with the inner protrusions 52 and 53 in the thickness direction of the tapered portions 13b and 13d, are in firm contact with the lesion 38. In this regard, in the above-mentioned embodiment, the second regions 58 and 59 are formed in the range of the outer surfaces of the tapered portions 13b and 13d including the overlapping regions 45 and 46 (in detail, the entire outer surface of the tapered portions 13b and 13d). Thus, the second regions 58 and 59 can be brought into firm contact with the lesion 38 in the overlapping regions 45 and 46. Therefore, it is possible to appropriately suppress the slippage of the balloon 13.

[0154] The surface roughness of the second regions 58a and 59a formed in the overlapping regions 45 and 46 of the tapered portions 13b and 13d is greater than the surface roughness of the other regions 58b and 59b. In this case, since the surface roughness is greater in the overlapping regions 45 and 46 that are in firm contact with the lesion 38, the slippage suppression effect of the balloon 13 can be improved.

[0155] The inner protrusions 52 and 53 of the tapered portions 13b and 13d and the outer protrusion 51 of the straight tube portion 13c are arranged at the same position in the circumferential direction of the balloon 13. In this case, the inner protrusions 52 and 53 and the outer protrusion 51 having high rigidity are arranged in the axial direction, so that when the lesion 38 is expanded by the tapered portions 13b and 13d, it is possible to make it more difficult for the tapered portions 13b and 13d to be pushed back from the lesion 38.

[0156] [Other embodiments]

[0157] The present disclosure is not limited to the above-described embodiments, and may be implemented as follows, for example.

[0158] In the above embodiments, the second region with a large surface roughness is formed on the outer surface of each tapered portion 13b, 13d, but the second region may be formed only on one of the tapered portions 13b, 13d. In this case, the first region with a small surface roughness is formed on the other tapered portion.

[0159] In the above-described embodiments, the second region is formed on the outer surface of each branch pipe portion 13a, 13e, but the first region may be formed on either or both of the branch pipe portions 13a, 13e.

[0160] In the second embodiment, the surface roughness of the second regions 42b and 42d of the tapered portions 13b and 13d decreases as they approach the straight tube portion 13c, but this may be changed. For example, the first region may be formed on the straight tube portion 13c side and the second region may be formed on the side opposite to the straight tube portion 13c side on the outer surface of each tapered portion 13b and 13d. In this case, the same effect as in the second embodiment may be obtained.

[0161] In the above-mentioned embodiments, the first region is formed on the entire outer surface of the straight tube portion 13c, but the first region may be formed only on a portion of the outer surface of the straight tube portion 13c. For example, the first region may be formed only on the central side in the axial direction of the outer surface of the straight tube portion 13c, and the second region may be formed on the base end side and the front end side in the axial direction. In this case, the effect of preventing the balloon 13 from slipping can be improved.

[0162] In the above-mentioned embodiments, the second region is provided on the outer surfaces of the tapered portions 13b and 13d over the entire circumferential region of the balloon 13, but this may be changed so that the second region is provided on the outer surfaces of the tapered portions 13b and 13d only over a portion of the circumferential region of the balloon 13. In this case, the first region is formed on the outer surfaces of the tapered portions 13b and 13d other than the portion described above.

[0163] In the third embodiment described above, the inner protrusions 52 and 53 are provided on the tapered portions 13 b and 13 d , respectively. However, the inner protrusion may be provided on only one of the tapered portions 13 b and 13 d .

[0164] ・In the third embodiment described above, a part of the inner wall surface 67d of the mold 60 is used 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 portion 61d) may be set to a circular shape. In this case, when the parison 47 is expanded, the protruding portion 48 of the parison 47 can be pressed against the inner wall surface 67d to be flattened to form the inner protruding portion 53. In addition, the surface that is in close contact with the inner wall surface 67d when the protruding portion 48 is flattened can form the second region 59a.

[0165] It should be noted that similarly, the inner wall surface 67 b of the mold 60 may not be provided with the projecting surface portion 73 and may be formed in a circular cross-sectional shape.

[0166] In the above-mentioned embodiments, the first region and the second region are formed on the outer surface of the balloon 13 using a mold during the expansion process, but the method of forming these regions is not necessarily limited to this. For example, the first region and the second region may be formed by cutting the outer surface of the balloon 13 after manufacturing the balloon 13.

[0167] The present disclosure is described according to the embodiments, but the present disclosure is understood to be not limited to the embodiments and structures. The present disclosure also includes various modifications and variations within the equivalent range. In addition, various combinations, methods, and other combinations and methods including only one element, more elements than it, or fewer elements than it also fall within the scope of the present disclosure and the scope of thought.

[0168] Description of reference numerals:

[0169] 10…balloon catheter, 11…catheter body, 13…balloon, 13a…base end side branch tube portion, 13b…base end side tapered portion, 13c…straight tube portion, 13d…front end side tapered portion, 13e…front end side branch tube portion, 21…first region, 22…second region, 30…mold, 31…inner 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…inner space.

Claims

1. A balloon catheter comprising a balloon capable of expansion and contraction, wherein: A first region and a second region which is provided at a portion of the balloon in the axial direction and has a surface roughness greater than that of the first region are formed on the outer surface of the balloon.

2. The balloon catheter according to claim 1, wherein: The balloon has: a straight tube portion having a largest diameter when expanded; and A pair of tapered portions, which are arranged on both sides of the straight tube portion in the axial direction and reduce in diameter toward a side away from the straight tube portion, The second region is formed on the outer surface of the tapered portion.

3. The balloon catheter according to claim 2, wherein: The second region is formed on the outer surface of the tapered portion on the front end side of the pair of tapered portions.

4. The balloon catheter according to claim 3, wherein: The balloon catheter comprises a catheter body having the balloon provided at the front end side. The balloon has a front end side branch tube portion, which is provided on the side opposite to the straight tube portion across the tapered portion on the front end side and is joined to the catheter body. The second region is formed on the outer surface of the distal branch pipe portion.

5. The balloon catheter according to any one of claims 2 to 4, wherein: The first region is formed on the outer surface of the straight tube portion.

6. The balloon catheter according to claim 5, wherein: The surface roughness of the second region of the tapered portion decreases as it approaches the straight tube portion.

7. The balloon catheter according to claim 2, wherein: The balloon catheter comprises a catheter body having the balloon provided at the front end side. The balloon has a branch tube portion, the branch tube portion is provided on the opposite side of the straight tube portion across the tapered portion where the second region is formed, and is joined to the catheter body. The second region is formed on the outer surface of the branch pipe portion.

8. The balloon catheter according to any one of claims 1 to 4, wherein: The second region is provided over the entire circumferential region of the balloon.

9. The balloon catheter according to claim 2, wherein: The tapered portion is provided with an inner protrusion, the inner protrusion protruding from the inner surface of the tapered portion and extending along the inner surface in the axial direction, The region of the outer surface of the tapered portion provided with the inner protrusion that overlaps with the inner protrusion in the thickness direction of the tapered portion is an overlapping region. The second region is formed in a range including the overlapping region of the outer surface of the tapered portion where the inner protrusion is provided.

10. The balloon catheter according to claim 9, wherein: A predetermined region of the second region formed in the overlapping region has a surface roughness greater than that of other regions.

11. The balloon catheter according to claim 9 or 10, wherein: The straight tube portion is provided with an outer protrusion protruding from an outer surface of the straight tube portion and extending in the axial direction. The inner protrusion and the outer protrusion are arranged at the same position in the circumferential direction of the balloon.

12. A method for manufacturing a balloon catheter, which is a method for manufacturing the balloon catheter according to claim 5, wherein: The balloon is manufactured using a mold having an inner space forming the balloon, The internal space has a first space portion forming the straight tube portion and a second space portion forming the tapered portion. The inner wall surface of the mold forming the inner space includes a first surface portion forming the first space portion and a second surface portion forming the second space portion. The surface roughness of the second surface is greater than the surface roughness of the first surface, The manufacturing method of the balloon catheter comprises: a disposing step of disposing a tubular parison, which will become a basis of the balloon, in the internal space; and an expansion step of expanding the parison in the internal space, In the expansion step, the first region is formed on the outer surface of the straight tube portion by bringing the outer circumferential surface of the expanded parison into close contact with the first surface portion, and the second region is formed on the outer surface of the tapered portion by bringing the outer circumferential surface of the expanded parison into close contact with the second surface portion.

13. The method for manufacturing a balloon catheter according to claim 12, wherein: The manufacturing method of the balloon catheter is applied to the following balloon catheter: the straight tube portion is provided with an outer protrusion protruding from the outer surface of the straight tube portion and extending in the axial direction, the tapered portion is provided with an inner protrusion protruding from the inner surface of the tapered portion and extending along the inner surface in the axial direction, The parison is provided with a protrusion protruding from the outer peripheral surface of the parison and extending in the longitudinal direction of the parison, A groove extending in the longitudinal direction of the internal space is formed on the first surface portion. The groove portion is not formed on the second surface portion, In the expansion step, the outer protrusion is formed by causing the protrusion of the expanded parison to enter the groove. In the expansion step, the expanded protrusion of the parison is pressed against the second surface portion to crush it, so that the portion of the parison along the protrusion protrudes inwardly to form the inner protrusion, and the surface in close contact with the second surface portion during the crushing forms the second region.

14. The method for manufacturing a balloon catheter according to claim 13, wherein: The second surface portion surrounding the second space portion becomes a protruding surface portion that protrudes toward the inner circumference in a part of the circumferential direction. In the expansion step, the protrusion is pressed against the extended surface portion to be crushed.

Images