Balloon catheter

Abstract

This balloon catheter is provided with a balloon (10), wherein: the balloon (10) has a straight tube part (13), a proximal-side tapered part positioned further toward the proximal side than the straight tube part (13), and a distal-side tapered part positioned further toward the distal side than the straight tube part (13); the balloon (10) has, on the outer surface of the balloon (10), a ridge (21) protruding outward in the radial direction; a plurality of ridges (21) are provided in the circumferential direction of the straight tube part (13); a plurality of regions with ridges (17) and a plurality of regions with no ridges (18) are formed on the outer surface of the straight tube part (13); the number of layers of the layer structure (including a single layer structure) of the balloon (10) is uniform across the plurality of regions with no ridges (18); and the balloon (10) has a wire material (22) that is disposed on the radially outer side of the regions with no ridges (18), and the wire material (22) is not fixed to the straight tube part (13).

Description

Balloon Catheter

[0001] The present disclosure relates to a balloon catheter.

[0002] It is known that stenosis occurring in blood vessels, which are channels for blood circulation in the body, impairs blood circulation and causes various diseases. In particular, stenosis occurring in the coronary artery that supplies blood to the heart may lead to serious diseases such as angina pectoris and myocardial infarction. One of the methods for treating such a stenotic site in a blood vessel is angioplasty (such as PTA and PTCA), in which a balloon catheter is used to dilate the stenotic site.

[0003] Some balloon catheters are known that have protrusions provided on the outer surface of the balloon (for example, Patent Documents 1 to 3). Balloon catheters in which wires are arranged on the outer surface of the balloon are also known (for example, Patent Documents 4 to 6). When such a balloon catheter is used, when the balloon is inflated, the protrusions or wires provided on the balloon can bite into the stenotic site, thereby effectively dilating the stenotic site.

[0004] International Publication No. WO 2020 / 250611 Japanese Unexamined Patent Publication No. 2009-112361 Japanese Unexamined Patent Publication No. 2013-176507 Japanese National Publication of International Patent Application No. 2008-539959 Japanese National Publication of International Patent Application No. 2015-505497 Japanese National Publication of International Patent Application No. 2021-521971

[0005] A balloon provided with protrusions or wires can exert a scoring function by means of the protrusions or wires. For example, by inflating the balloon at a calcified lesion, cracks can be formed or the calcified lesion can be fractured. However, conventional balloons cannot cope with highly advanced calcified lesions, and even if the inflation pressure of the balloon is sufficiently increased, cracks may not be formed or the calcified lesion may not be fractured in some cases.

[0006] An object of the present disclosure is to provide a balloon catheter capable of exerting a sufficient scoring function even on a highly advanced calcified lesion.

[0007] The balloon catheter according to the present disclosure that has been able to solve the above problems is as follows: [1] A balloon catheter equipped with a balloon, wherein the balloon has a longitudinal axis direction extending from the proximal to the distal side, and a radial direction and a circumferential direction perpendicular to the longitudinal axis direction, and has a straight tube portion, a proximal tapered portion located proximal to the straight tube portion, and a distal tapered portion located distal to the straight tube portion, the balloon has a convex ridge projecting outward in the radial direction on the outer surface of the balloon, a plurality of convex ridges are provided in the circumferential direction of the straight tube portion, and a plurality of convex ridge-present regions and a plurality of convex ridge-absent regions are formed on the outer surface of the straight tube portion, the number of layers of the layer structure (including a single-layer structure) of the balloon in the plurality of convex ridge-absent regions is the same, and the balloon is a balloon catheter in which a wire that is not fixed to the straight tube portion is arranged on the radially outward side of the convex ridge-absent region. [2] The balloon catheter according to [1], wherein in the vertical cross section of the straight tube portion in the longitudinal direction, at least one pair of ribs arranged adjacent to each other in the circumferential direction are spaced apart at an angle of 30° to 150° with respect to the longitudinal axis center of the balloon, and the wire is positioned between the pair of ribs. [3] The balloon catheter according to [1], wherein in the vertical cross section of the straight tube portion in the longitudinal direction, the plurality of ribs are spaced apart at an angle of 30° to 150° with respect to the longitudinal axis center of the balloon. [4] The balloon catheter according to any one of [1] to [3], wherein the balloon has a proximal sleeve portion located proximal to the proximal tapered portion and a distal sleeve portion located distal to the distal tapered portion, the proximal end of the wire is fixed to the proximal sleeve portion and / or the proximal tapered portion, and the distal end of the wire is fixed to the distal sleeve portion and / or the distal tapered portion. [5] The balloon catheter according to any one of [1] to [4], wherein the protrusion is made of resin.[6] The balloon catheter according to any one of [1] to [5], wherein the balloon has a balloon body and a ridge projecting radially outward from the outer surface of the balloon body, and the balloon body and the ridge are formed from the same material. [7] The balloon catheter according to any one of [1] to [6], wherein the wire is made of metal. [8] The balloon catheter according to any one of [1] to [7], wherein the cross-sectional shape of the ridge and the cross-sectional shape of the wire are different from each other. [9] The balloon catheter according to any one of [1] to [8], wherein two or more wires are not arranged in each of the plurality of regions where no ridges are present.

[10] The balloon catheter according to any one of [1] to [9], wherein, in the contracted state of the balloon, the straight tube portion is folded back in the region where no ridges are present with the inner surface of the balloon facing inward, and has a folded wing portion where the regions where no ridges are present overlap, and the folded wing portion is arranged to overlap the outer surface of the balloon and cover the wire.

[11] In the deflated state of the balloon, the straight tube portion is folded back in the region where the convex ridge is absent, with the inner surface of the balloon facing inward, and has a folded wing portion where the regions where the convex ridge is absent overlap, the folded wing portion is arranged to overlap the outer surface of the balloon, and the wire is arranged on the radially outward side of the folded wing portion, according to any one of [1] to [9].

[0008] The balloon catheter described herein can provide sufficient scoring functionality for highly calcified lesions.

[0009] Figure 1 shows an example of the configuration of a balloon catheter according to an embodiment of the present disclosure, and represents a side view of the balloon catheter. Figure 2 shows a cross-sectional view taken along line II-II of the balloon catheter shown in Figure 1. Figure 3 shows a cross-sectional view taken along line III-III of the balloon catheter shown in Figure 1. Figure 4 shows a vertical cross-sectional view of the balloon in the direction of its longitudinal axis. Figure 5 shows a partially enlarged cross-sectional view of the balloon around a protrusion. Figure 4 shows an example of the folded state of the balloon, and represents a vertical cross-sectional view of the folded balloon in the direction of its longitudinal axis. Figure 5 shows another example of the folded state of the balloon, and represents a vertical cross-sectional view of the folded balloon in the direction of its longitudinal axis.

[0010] The contents of this disclosure will be described in detail below based on the embodiments described below. However, the contents of this disclosure are not limited by the embodiments described below, and it is certainly possible to implement the disclosure with appropriate modifications to the extent that it is in line with the spirit of the preceding and following descriptions, and all such modifications are included within the technical scope of this disclosure. In addition, hatching and component reference numerals may be omitted in the drawings for convenience, in which case refer to the specification or other drawings. Furthermore, the dimensions of various components in the drawings may differ from the actual dimensions, as priority is given to helping to understand the features of this disclosure.

[0011] Examples of the configuration of a balloon catheter according to the embodiments of this disclosure will be described with reference to the drawings. Figures 1 to 4 show examples of the configuration of a balloon catheter according to this disclosure. Figure 1 is a side view of the balloon catheter, Figure 2 is a cross-sectional view taken along line II-II of the balloon catheter shown in Figure 1, Figure 3 is a cross-sectional view taken along line III-III of the balloon catheter shown in Figure 1, and Figure 4 is a perspective view of the balloon provided in the balloon catheter shown in Figure 1. Figure 1 shows an example of the configuration of a rapid exchange type balloon catheter.

[0012] The balloon catheter 1 has a balloon 10. Specifically, the balloon catheter 1 has a shaft 2 and a balloon 10 provided on the outside of the shaft 2. The balloon catheter 1 has a proximal end and a distal end, with the balloon 10 provided at the distal end of the shaft 2. The proximal end of the balloon catheter 1 refers to the direction toward the user (operator) relative to the extending direction of the balloon catheter 1, and the distal end refers to the opposite direction from the proximal end, i.e., the direction toward the target of treatment. The direction from the proximal end to the distal end of the balloon catheter 1 is also called the longitudinal axis direction.

[0013] The balloon catheter 1 is configured to supply fluid into the balloon 10 through the shaft 2, and the expansion and contraction of the balloon 10 can be controlled using an indefleror (balloon pressure / depressurization device). The fluid may be pressurized fluid pressurized by a pump or the like. Hereinafter, the fluid supplied into the balloon 10 will be referred to as the "balloon expansion fluid".

[0014] The shaft 2 is composed of, for example, an inner shaft 3 and an outer shaft 4. The inner shaft 3 is positioned within the lumen of the outer shaft 4. The inner shaft 3 can function as a passage for a guidewire that guides the advancement of the shaft 2, and when the balloon catheter 1 is used, the guidewire is inserted through the lumen of the inner shaft 3. The space between the inner shaft 3 and the outer shaft 4 can function as a passage for the balloon inflation fluid.

[0015] In the rapid exchange type balloon catheter 1, a guidewire port 7 is provided midway from the distal to the proximal end of the shaft 2. The proximal end of the inner shaft 3 is connected to the guidewire port 7, and the distal end of the inner shaft 3 extends to the distal part of the shaft 2, thereby forming a guidewire insertion passage that extends from the guidewire port 7 to the distal part of the shaft 2.

[0016] The outer shaft 4 may have a proximal outer shaft 4A and a distal outer shaft 4B, in which case it is preferable that the inner shaft 3 is positioned in the lumen of the distal outer shaft 4B. The proximal outer shaft 4A and the distal outer shaft 4B may be made of the same material or of different materials. For example, it is preferable that the proximal outer shaft 4A is made of resin or metal and the distal outer shaft 4B is made of resin. The outer shaft 4 may not be divided into a proximal outer shaft 4A and a distal outer shaft 4B, but may be made of a single member, or the proximal outer shaft 4A and the distal outer shaft 4B may be further made of multiple tube members.

[0017] It is preferable that a hub 5 is provided on the proximal side of the shaft 2. The hub 5 preferably has a fluid injection section 6 that communicates with the flow path of the balloon expansion fluid in the shaft 2. The balloon 10, shaft 2 (inner shaft 3, outer shaft 4), and hub 5 can be joined using conventionally known joining methods such as adhesives or heat welding.

[0018] Although not shown in the drawings, the balloon catheter may be an over-the-wire type balloon catheter in which the inner shaft extends from the distal to the proximal end of the shaft, and a guidewire insertion passage is formed from the distal to the proximal end of the shaft. In this case, it is preferable that the flow path for the balloon inflation fluid and the guidewire insertion passage provided in the shaft extend to the hub, and that the hub is configured to have a fluid injection section communicating with the flow path for the balloon inflation fluid and a treatment section communicating with the guidewire insertion passage. It is preferable that the hub has a bifurcated structure, with the fluid injection section provided on one of the bifurcated ends and the treatment section on the other.

[0019] It is preferable that the outer surface of the shaft 2 is coated. In a rapid exchange type balloon catheter 1, it is preferable that the outer surface of one or both of the proximal outer shaft 4A and the distal outer shaft 4B is coated, and it is more preferable that the outer surfaces of both the proximal outer shaft 4A and the distal outer shaft 4B are coated. In an over-the-wire type balloon catheter, it is preferable that the outer surface of the outer shaft is appropriately coated.

[0020] The coating can be hydrophilic or hydrophobic depending on the purpose. The outer surface of the shaft 2 can be coated by immersing the shaft 2 in a hydrophilic or hydrophobic coating agent, applying a hydrophilic or hydrophobic coating agent to the outer surface of the shaft 2, or covering the outer surface of the shaft 2 with a hydrophilic or hydrophobic coating agent. The coating agent may contain chemicals or additives.

[0021] Examples of hydrophilic coating agents include hydrophilic polymers such as polyvinyl alcohol, polyethylene glycol, polyacrylamide, polyvinylpyrrolidone, and methyl vinyl ether maleic anhydride copolymer, as well as hydrophilic coating agents made from any combination of these polymers.

[0022] Examples of hydrophobic coating agents include polytetrafluoroethylene (PTFE), fluoroethylene propylene (FEP), perfluoroalkoxyalkanes (PFA), silicone oil, hydrophobic urethane resins, carbon coatings, diamond coatings, diamond-like carbon (DLC) coatings, ceramic coatings, and substances with low surface free energy terminated with alkyl groups or perfluoroalkyl groups.

[0023] Preferably, a tip 8 is provided at the distal end of the balloon catheter 1. The tip 8 may be provided as a separate component from the inner shaft 3 distal to the distal end of the inner shaft 3, or the distal end of the inner shaft 3 may function as the tip 8 by extending the inner shaft 3 distal to the distal end of the balloon 10.

[0024] The shaft 2 may have radiopaque markers 9 positioned in the portion where the balloon 10 is located in relation to the longitudinal axis, in order to allow confirmation of the balloon 10's position under X-ray fluoroscopy. The radiopaque markers 9 can be positioned, for example, on the inner shaft 3 located inside the balloon 10, preferably at positions corresponding to both ends of the straight section of the balloon 10, or at a position corresponding to the center of the straight section of the balloon 10.

[0025] The balloon 10 is formed in a cylindrical shape with a longitudinal axis direction and a radial direction, and openings on the proximal and distal ends. The longitudinal axis direction of the balloon 10 corresponds to the direction extending from the proximal to the distal end of the balloon catheter 1, and the radial direction of the balloon 10 is the direction perpendicular to the longitudinal axis direction, meaning the direction extending radially from the center of the balloon 10. The balloon 10 also has a circumferential direction perpendicular to the longitudinal axis direction. The circumferential direction of the balloon 10 is defined as the direction along the outer circumference of the expanded balloon 10 in a cross section perpendicular to the longitudinal axis direction of the balloon 10. The tubular membrane portion of the balloon 10 is referred to as the balloon body portion 16, and the balloon 10 has a tubular balloon body portion 16.

[0026] As shown in Figure 4, it is preferable that the balloon 10 has a straight tube section 13, a proximal tapered section 12 located proximal to the straight tube section 13, and a distal tapered section 14 located distal to the straight tube section 13, with respect to the longitudinal axis. The straight tube section 13 is formed in a substantially cylindrical shape extending in the longitudinal axis and has the largest radial length (outer diameter) in the balloon 10. The proximal tapered section 12 is located proximal to the straight tube section 13 and connects to the proximal end of the straight tube section 13. The proximal tapered section 12 is formed such that its outer diameter decreases as it moves away from the straight tube section 13. The distal tapered section 14 is located distal to the straight tube section 13 and connects to the distal end of the straight tube section 13. The distal tapered section 14 is formed such that its outer diameter decreases as it moves away from the straight tube section 13. Preferably, the balloon 10 further has a proximal sleeve portion 11 located proximal to the proximal tapered portion 12 and a distal sleeve portion 15 located distal to the distal tapered portion 14. The proximal sleeve portion 11 is located proximal to the proximal tapered portion 12 and connects to the proximal end of the proximal tapered portion 12. The proximal sleeve portion 11 is formed in a substantially cylindrical shape. The distal sleeve portion 15 is located distal to the distal tapered portion 14 and connects to the distal end of the distal tapered portion 14. The distal sleeve portion 15 is formed in a substantially cylindrical shape.

[0027] As described above, the balloon 10 is configured such that when the balloon 10 is expanded in the narrowed area, the straight tube portion 13 makes sufficient contact with the narrowed area, making it easier to perform treatments such as dilation of the narrowed area. Furthermore, because the balloon 10 has a proximal tapered portion 12 and a distal tapered portion 14, when the balloon 10 is deflated, the outer diameters of the proximal and distal ends of the balloon 10 can be reduced, thereby reducing the step difference between the shaft 2 and the balloon 10, making it easier to insert the balloon 10 into a body cavity, into the forceps channel of an endoscope, or into a delivery catheter such as a guiding catheter.

[0028] In the distal portion of the shaft 2, it is preferable that the inner shaft 3 extends distally from the distal end of the outer shaft 4, and that the inner shaft 3 extends through the internal space of the balloon 10 from the proximal sleeve portion 11 to the distal sleeve portion 15. Furthermore, it is preferable that the outer surface of the inner shaft 3 is joined to the inner surface of the distal sleeve portion 15 of the balloon 10, and the outer surface of the outer shaft 4 is joined to the inner surface of the proximal sleeve portion 11 of the balloon 10. With the distal portion of the shaft 2 configured in this way, the balloon expansion fluid can be supplied to the internal space of the balloon 10 through the space between the inner shaft 3 and the outer shaft 4.

[0029] The size of the balloon 10 is not particularly limited. For example, the size of the balloon 10 can be appropriately set within the range of 4 mm to 400 mm for the length in the longitudinal axis direction of the straight tube section 13 and 0.7 mm to 30 mm for the outer diameter of the straight tube section 13.

[0030] The balloon 10 (especially the balloon body 16) is preferably made of a resin, and more preferably of a thermoplastic resin. This makes it easier to manufacture the balloon 10 by molding. Examples of resins that make up the balloon 10 include polyolefin resins such as polyethylene, polypropylene, and ethylene-propylene copolymer; polyester resins such as polyethylene terephthalate and polyester elastomer; polyurethane resins such as polyurethane and polyurethane elastomer; polyamide resins such as polyphenylene sulfide resin, polyamide, and polyamide elastomer; fluororesin, silicone resin, and natural rubber such as latex rubber. These may be used alone or in combination of two or more. Among these, polyamide resins, polyester resins, and polyurethane resins are preferably used. In particular, it is preferable to use elastomer resins from the viewpoint of thinning the balloon 10 and its flexibility. For example, among polyamide resins, nylon 12 and nylon 11 are suitable materials for the balloon 10, and nylon 12 is preferably used because it can be molded relatively easily when blow molding. Furthermore, from the viewpoint of thinning the balloon 10 and improving its flexibility, polyamide elastomers such as polyether ester amide elastomers and polyamide ether elastomers are preferably used. Among these, polyether ester amide elastomers are preferably used because they have high yield strength and good dimensional stability of the balloon 10.

[0031] The outer surface of the balloon 10 is provided with protrusions 21. The protrusions 21 are provided on the outer surface of the balloon 10, projecting radially outward. The protrusions 21 give the balloon 10 a scoring function, and when the balloon 10 is expanded in a lesion such as a narrowed part of a blood vessel, it can bite into the calcified lesion and cause a crack. Therefore, it is possible to expand the narrowed part while suppressing vascular dissection. It is also possible to increase the pressure resistance of the balloon 10 and suppress over-expansion when pressurized. Although the balloon 10 can also be used to treat lesions such as narrowed parts of body cavities other than blood vessels, the following explanation will focus on the application of the balloon 10 to vascular treatment.

[0032] The ridges 21 of the balloon 10 will be described in detail with reference to Figures 5 and 6. Figure 5 shows a vertical cross-sectional view of the straight pipe section 13 of the balloon 10 in the longitudinal direction, and Figure 6 shows an enlarged cross-sectional view of the ridges 21 of the balloon 10. Figure 5 shows an example of the configuration in the vertical cross-section of the straight pipe section 13 of the balloon 10 in the longitudinal direction shown in Figure 4, in which the ridges 21 are provided at three locations in the circumferential direction of the straight pipe section 13.

[0033] The balloon 10 has a balloon body portion 16, and a protrusion 21 is provided on the outer surface of the balloon body portion 16. The protrusion 21 is provided so as to project radially outward from the outer surface of the balloon body portion 16. As a result of the provision of the protrusion 21, a region 17 where the protrusion exists and a region 18 where the protrusion does not exist are formed on the outer surface of the straight tube portion 13 of the balloon 10. Notches may be formed in the protrusion 21, in which case the portion where the notch is formed is also included in the region 17 where the protrusion exists.

[0034] In the balloon 10, the portion excluding the radially outwardly protruding ridge 21 becomes the balloon body portion 16. In a vertical cross-section along the longitudinal axis of the balloon 10, it is preferable that the outer shape of the balloon body portion 16 is substantially circular. In the straight tube portion 13, it is preferable that the outer surface of the balloon body portion 16 is cylindrical. The region 17 where the ridge exists is composed of the balloon body portion 16 and the ridge 21, and the region 18 where the ridge does not exist is composed of the balloon body portion 16.

[0035] The outer surface of the straight tube section 13 is preferably formed flat in the ridge-free region 18. For example, it is preferable that the outer surface of the straight tube section 13 is not formed with depressions in a part of the ridge-free region 18. This makes it easier to evenly expand the balloon 10 and makes it easier to achieve the scoring function of the ridges 21 as desired. Note that the outer surface of the straight tube section 13 being formed flat in the ridge-free region 18 means that the ridge-free region 18 is shaped like a plane that has been curved into an arch, and no irregularities are formed in the curved plane. This irregularity does not include surface roughness that is inevitably formed during manufacturing. It is also preferable that the outer surfaces of the proximal tapered section 12 and the distal tapered section 14 of the balloon 10 are formed flat in the ridge-free region 18.

[0036] The protrusion 21 has a top portion 21A and a base portion 21B (see Figure 6). In the protrusion 21, the top portion 21A refers to the tip of the protrusion 21, i.e., the outermost part of the protrusion 21 in the radial direction, and the base portion 21B refers to the boundary with the balloon body portion 16, i.e., the innermost part of the protrusion 21 in the radial direction.

[0037] The protrusions 21 can be made of, for example, resin. If the protrusions 21 are made of resin, the balloon 10 having the protrusions 21 can be manufactured by resin molding, making manufacturing easier. In this case, it is preferable that the protrusions 21 and the balloon body 16 are made of the same resin, and it is preferable that the protrusions 21 and the balloon body 16 are integrally molded. The balloon body 16 may have an inner layer and an outer layer, and in this case, it is preferable that the protrusions 21 are made of the same resin as the outer layer of the balloon body 16. This makes it less likely that the protrusions 21 will unintentionally detach from the balloon body 16. Alternatively, if the resin constituting the protrusions 21 and the resin constituting the balloon body 16 have a certain degree of compatibility, the protrusions 21 and the balloon body 16 may be made of different resins.

[0038] The protrusion 21 may be made of metal, or a combination of metal and resin. In this case, it is preferable that the portion of the protrusion 21 including the top 21A is made of metal. For example, the entire protrusion 21 may be made of metal, or the portion of the protrusion 21 including the base 21B may be made of resin, and the portion of the protrusion 21 including the top 21A may be made of metal.

[0039] The ridges 21 are provided on the outer surface of the balloon 10 so as to extend in a ridge-like manner. Preferably, the ridges 21 are provided so as to extend in the longitudinal direction of the balloon 10. In this case, the ridges 21 may extend parallel to the longitudinal direction or diagonally to the longitudinal direction. In order to enhance the scoring function of the balloon 10 and to facilitate the manufacture of the balloon 10 having the ridges 21, it is preferable that the ridges 21 extend at an angle of ±30° or less with respect to the longitudinal direction, but it may also be at an angle of ±20° or ±15° or less. As the ridges 21 are provided so as to extend in the longitudinal direction of the balloon 10, the outer surface of the balloon 10 is divided in the circumferential direction into a region 17 where ridges exist and a region 18 where ridges do not exist.

[0040] The ridges 21 are provided at least on the straight section 13. This makes it easier for the ridges 21 to penetrate deeply into the narrowed portion of a blood vessel when the balloon 10 is expanded, thereby enhancing the scoring function of the ridges 21. The ridges 21 may be provided in a range of 60% or more, 70% or more, or 80% or more in the longitudinal direction of the straight section 13, thereby making it possible to create cracks over a wide area of ​​the narrowed portion when the balloon 10 is expanded. The ridges 21 may be provided in a range of 90% or more in the longitudinal direction of the straight section 13, or they may be provided over almost the entire longitudinal direction of the straight section 13. The ridges 21 may also be provided on the outer surface of the proximal tapered section 12 and / or the distal tapered section 14, and on the outer surface of the proximal sleeve section 11 and / or the distal sleeve section 15.

[0041] Multiple ridges 21 are provided in the circumferential direction of the straight pipe section 13. Specifically, multiple ridges 21 are provided at different positions in the circumferential direction in a vertical cross-section in the longitudinal axis direction of the straight pipe section 13. As a result, multiple regions 17 with ridges and multiple regions 18 without ridges are formed on the outer surface of the straight pipe section 13. The number of regions 18 without ridges is equal to the number of ridges 21.

[0042] Preferably, the protruding strips 21 provided at a plurality of positions in the circumferential direction of the balloon 10 are arranged at substantially equal intervals in the circumferential direction of the balloon 10. The protruding strips 21 may be provided at 2 or more positions, or 3 or more positions, in the circumferential direction of the balloon 10, and may be provided at 12 or less positions, 8 or less positions, or 6 or less positions. Further, in this case, it is preferable that the interval between the protruding strips 21 in the circumferential direction is longer than the length of one protruding strip 21 in the circumferential direction. In FIG. 5, the protruding strips 21 are provided at three positions in the circumferential direction of the balloon 10.

[0043] The layered structure of the balloon 10 may be a single-layer structure or a multi-layer structure, but it is preferable that the number of layers of the layered structure of the balloon 10 in the plurality of protruding strip non-existing regions 18 is the same as each other. This makes it easy to uniformly expand the balloon 10 in the circumferential direction, and makes it easy to exert the scoring function of the protruding strips 21 as desired.

[0044] The cross-sectional shape of the protruding strip 21 is not particularly limited. For example, the shape of the protruding strip 21 in a cross-section perpendicular to the extending direction of the protruding strip 21 includes polygons such as triangles and quadrilaterals, partial circular shapes such as semicircles and sectors, wedge shapes, convex shapes, spindle shapes, indefinite shapes, and the like. Polygons include not only those with clear corner vertices and straight sides, but also rounded polygons with rounded corners, and those with at least part of the sides being curved. It should be noted that the protruding strip 21 is preferably formed such that the width thereof gradually decreases toward the top portion 21A.

[0045] In a cross-section perpendicular to the extending direction of the protruding strip 21, it is preferable that the height of the protruding strip 21 is 0.2 times or more the width (maximum width) of the protruding strip 21. When the protruding strip 21 is formed in this manner, when the balloon 10 is expanded at the stenotic site, the protruding strip 21 easily bites into the stenotic site, and the scoring function of the protruding strip 21 can be enhanced. The protruding strip 21 is preferably formed to have the maximum width at the base portion 21B, whereby the protruding strip 21 can be stably installed on the outer surface of the balloon body portion 16. The height of the protruding strip 21 may be 0.4 times or more, or 0.7 times or more the width of the protruding strip 21. On the other hand, the height of the protruding strip 21 may be 2.0 times or less, 1.8 times or less, or 1.5 times or less the width of the protruding strip 21. This makes it easy to ensure the flexibility of the balloon 10 at the portion where the protruding strips 21 are provided.

[0046] In the balloon 10, it is preferable that the thickness of a portion provided with the protruding ridges 21, that is, the thickness of the protruding ridge existing region 17, is formed thicker than the thickness of a portion not provided with the protruding ridges 21, that is, the thickness of the protruding ridge non-existing region 18. Thereby, the scoring function provided by the protruding ridges 21 can be enhanced. The thickness (maximum thickness) of the protruding ridge existing region 17 may be 1.5 times or more, 2.0 times or more, or 2.5 times or more the thickness (maximum thickness) of the protruding ridge non-existing region 18. The upper limit of the thickness of the protruding ridge existing region 17 is not particularly limited, and for example, it may be 30 times or less, 20 times or less, or 10 times or less the thickness of the protruding ridge non-existing region 18.

[0047] The balloon 10 may have inner protruding ridges protruding radially inward on the inner surface of the balloon 10 (not shown). The protruding ridges 21 and the inner protruding ridges may be arranged at the same position relative to the longitudinal axial direction and the circumferential direction of the balloon 10, and they are preferably integrally formed, whereby a part of the balloon 10 may be formed to have a thick wall.

[0048] In the balloon 10, a wire 22 is arranged on the radially outer side of the protruding ridge non-existing region 18. Unlike the protruding ridges 21, the wire 22 is not fixed to the straight pipe portion 13. When the balloon 10 is expanded, the wire 22 is pushed outward in the radial direction by the balloon main body portion 16, making it possible for the wire to bite into a calcified lesion and form a crack therein.

[0049] In addition to being arranged on the straight pipe portion 13, the wire 22 is also preferably arranged on the radially outer side of the proximal tapered portion 12 and / or the distal tapered portion 14, and is more preferably also arranged on the radially outer side of both the proximal tapered portion 12 and the distal tapered portion 14. The wire 22 may also be arranged on the radially outer side of the proximal sleeve portion 11 and / or the distal sleeve portion 15 of the balloon main body portion 16.

[0050] Preferably, the proximal and distal ends of the wire 22 are fixed to a portion of the balloon 10 other than the straight tube portion 13 or to the shaft 2, and the portion between the proximal and distal ends is not fixed to the straight tube portion 13. More preferably, the proximal end of the wire 22 is fixed to the proximal sleeve portion 11 and / or the proximal tapered portion 12, and the distal end of the wire 22 is fixed to the distal sleeve portion 15 and / or the distal tapered portion 14.

[0051] The wire 22 is preferably provided so as to extend in the longitudinal direction of the balloon 10. In this case, the wire 22 may extend parallel to the longitudinal direction, or it may extend diagonally in the longitudinal direction. The wire 22 is preferably extended on the outer surface of the straight pipe section 13 at an angle of ±30° or less with respect to the longitudinal direction, but it may also be at an angle of ±20° or less or ±15° or less. The direction of extension of the wire 22 means the direction in which the wire 22 extends when the balloon 10 is expanded and tension is applied to the wire 22.

[0052] The wire 22 may be provided as a single wire or as two or more wires on the radially outward side of the region 18 where no protrusions exist. In addition, it is preferable to provide two or more wires 22, and it is preferable to provide wires 22 in multiple regions 18 where no protrusions exist, in order to enhance the effect of the wire 22.

[0053] The wire 22 can be made of metal or resin. Examples of metals that make up the wire 22 include stainless steel such as SUS304 and SUS316, carbon steel, platinum, nickel, cobalt, chromium, titanium, tungsten, gold, nickel-titanium alloy, cobalt-chromium alloy, and tungsten alloy. Examples of resins that make up the wire 22 include polyolefin resins such as polyethylene, polypropylene, and ethylene-propylene copolymer, polyester resins such as polyethylene terephthalate, polyamide resins such as nylon, aromatic polyether ketone resins such as PEEK, polyurethane resin, polyether polyamide resin, polyimide resin, polyamide-imide resin, fluororesins such as PTFE, PFA, and ETFE, polyvinyl chloride resin, and silicone resin. Only one of these may be used, or two or more may be used in combination. The wire 22 may be made of the same material as the convex rib 21, or it may be made of a different material.

[0054] The cross-sectional shape of the wire 22 is not particularly limited. For example, the shape of the wire 22 in a cross-section perpendicular to the direction of extension can be circular, elliptical, oblong, polygonal, irregular, etc. Polygons include not only those with clearly defined corner vertices and straight sides, but also rounded polygons with rounded corners and those with at least a portion of their sides being curved. The wire 22 may be a single wire or a stranded wire.

[0055] As described above, the balloon catheter 1 has a ridge 21 on the outer surface of the straight tube portion 13 of the balloon 10, and a wire 22 that is not fixed to the straight tube portion 13 is provided radially outward from the region 18 where the ridge is not present. Therefore, when the balloon 10 is expanded, it is possible to crack or rupture highly calcified lesions. Specifically, compared to a balloon with only one of the ridge or the wire, the balloon catheter 1 equipped with both the ridge 21 and the wire 22 can crack or rupture highly calcified lesions at a lower balloon expansion pressure. The results of verifying this effect using a calcified lesion model are described below. Note that the following experimental results are not limiting to this disclosure.

[0056] In Experiment 1, a cylindrical gypsum model 1 with an inner diameter of 1.50 mm, a thickness of 250 μm, and a length of 10 mm was prepared as a calcified lesion model. The calcified lesion models were prepared after more than one year had passed since their creation and had hardened sufficiently. Balloon A had three protrusions on its outer surface and no wires were placed on its outer surface; balloon B had no protrusions on its outer surface and one wire was placed on its outer surface; and balloon C had three protrusions on its outer surface and one wire was placed in the area of ​​the balloon where no protrusions were present. All balloons had an outer diameter of 3.00 mm and a length of 10 mm in the straight section.

[0057] Balloons A to C were inserted into the lumen of cylindrical model 1, a calcified lesion model. Balloon expansion fluid was supplied to the inside of the balloons, and the balloons were expanded until the calcified lesion model ruptured. The expansion pressure (rupture pressure) at the time the calcified lesion model ruptured was measured. As a result, the rupture pressure of balloon A was 17 atm, the rupture pressure of balloon B was 21 atm, and the rupture pressure of balloon C was 10 atm. Compared to balloons A and B, which had only one of the convex or linear material on their outer surface, balloon C, which had both convex and linear material on its outer surface, was able to rupture cylindrical model 1 at a lower balloon expansion pressure.

[0058] In Experiment 2, a cylindrical model 2 was prepared as a calcified lesion model, with the length of cylindrical model 1 being 15 mm. As balloons, balloon C, as described above, and balloon D, which had no protrusions on its outer surface but had three wires arranged on it, were prepared. Balloon D also had an outer diameter of 3.00 mm and a length of 10 mm in the straight section.

[0059] Balloons C and D were inserted into the lumen of cylindrical model 2, a calcified lesion model. Balloon expansion fluid was supplied to the inside of the balloons, and the balloons were expanded until the calcified lesion model ruptured. The expansion pressure (rupture pressure) at the point when the calcified lesion model ruptured was measured. As a result, the rupture pressure of balloon C was 22 atm, and balloon D could not rupture cylindrical model 2 even at an expansion pressure of 30 atm.

[0060] The mechanism by which a balloon 10 equipped with both ridges 21 and wires 22 can rupture calcified lesions at a lower balloon expansion pressure is thought to be as follows: When a balloon 10 equipped with both ridges 21 and wires 22 is expanded over a calcified lesion, the ridges 21 first come into contact with the inner surface of the lesion. If the balloon 10 continues to expand in this state, the lesion between the ridges 21 that are in contact with the inner surface of the lesion is expanded radially and circumferentially, and tension is applied to the lesion between the ridges 21. The lesion is pushed outward in the circumferential direction by the anchoring effect of the ridges 21. If the balloon 10 is further expanded in this state, the wires 22 positioned in the ridge-free region 18 on the outer surface of the balloon 10 are pressed against the lesion, which is pushed outward in the circumferential direction and under tension, and stress concentration is applied by the wires 22. This further increases the expansion force of the lesion, making it possible to effectively crack or rupture even highly calcified lesions. The expansion pressure of the non-convex region 18 is concentrated on the wire 22, allowing the wire 22 to be pressed firmly against the lesion.

[0061] In Experiment 1, a calcified lesion model was used with a length close to that of the balloon. In this case, the wire was pressed against the end of the calcified lesion, generating a bending moment and concentrating force at the end of the calcified lesion. As a result, using balloon C, which has both ridges and wire on its outer surface, the calcified lesion could be ruptured at a lower balloon expansion pressure. In Experiment 2, where a calcified lesion model was used with a length longer than the straight section of the balloon, the rupture pressure was higher than in Experiment 1. However, even when the wire was not pressed against the end of the calcified lesion, and no bending moment was generated, and force was not concentrated at the end of the calcified lesion, using balloon C, which has both ridges and wire on its outer surface, allowed the calcified lesion to be ruptured at a lower balloon expansion pressure, regardless of the length of the lesion, compared to a balloon with only one of the ridges or wire on its outer surface.

[0062] In a vertical cross-section of the straight tube section 13 in the longitudinal direction, at least one pair of circumferentially adjacent protrusions 21 are spaced apart at an angle of 30° to 150° with respect to the longitudinal axis center of the balloon 10, and preferably the wire 22 is placed between the pair of protrusions 21. This allows the lesion between the protrusions 21 to be effectively spread and tensioned in the circumferential direction when the balloon 10 is expanded. The separation angle of the pair of protrusions 21 may be 50° or more, 80° or more, or 130° or less.

[0063] In the vertical cross-section of the straight pipe section 13 in the longitudinal direction, it is more preferable that the multiple protrusions 21 are arranged such that adjacent protrusions 21 are spaced apart at an angle of 30° to 150° with respect to the longitudinal axis center of the balloon 10. That is, it is preferable that all of the multiple protrusions 21 are arranged on the outer surface of the balloon 10 at such a separation angle. The separation angle between adjacent protrusions 21 in the circumferential direction may be 50° or more, 80° or more, or 130° or less.

[0064] The separation angle of adjacent ribs 21 in the circumferential direction refers to the angle formed at the longitudinal axis center of the balloon 10 by the line segment connecting the circumferential center of the base 21B of the rib 21 and the longitudinal axis center of the balloon 10, and the line segment connecting the circumferential center of the base 21B of the rib 21 adjacent to the rib 21 in the circumferential direction and the longitudinal axis center of the balloon 10, when the balloon 10 is expanded. The longitudinal axis center of the balloon 10 corresponds to the centroid of the outer edge of the balloon body 16 (the outer edge of the balloon body 16 excluding the ribs 21) in a vertical cross-section in the longitudinal direction of the balloon 10.

[0065] It is preferable that the wires 22 be provided in each ridge-free region 18. Specifically, it is preferable that they be provided in each ridge-free region 18 when the balloon 10 is expanded. Only one wire 22 may be provided in each ridge-free region 18, or two or more may be provided. It is preferable that only one wire 22 is provided in each ridge-free region 18. In other words, it is preferable that no more than two wires 22 are placed in each of the multiple ridge-free regions 18. This prevents the wires 22 from becoming entangled or interfering with each other when the balloon 10 is expanded.

[0066] It is preferable that, when the balloon 10 is expanded and bent at a 45° angle in the longitudinal direction, no more than two wires 22 are placed in each of the multiple ridge-free regions 18. For example, in shunts formed during hemodialysis, the blood vessels are greatly bent at the arteriovenous anastomosis. Also, in balloons for the lower limbs, the balloon is inserted into the iliac artery during treatment, and the blood vessels are greatly bent at the bifurcation where the left and right iliac arteries branch off from the abdominal aorta. When a balloon 10 with multiple wires 22 arranged on its outer surface but no ridges 21 is expanded at such a bent portion of a blood vessel, the multiple wires 22 tend to accumulate on the inside of the bend. In this case, strong force tends to concentrate on the inside of the bend, increasing the risk of vascular dissection. However, with a balloon 10 having both ridges 21 and wires 22 on its outer surface, even when expanded at a bent portion of a blood vessel, the ridges 21 on the balloon 10 can prevent the multiple wires 22 from accumulating on the inside of the bend. From this perspective, it is preferable that when the balloon 10 is expanded and bent at a 45° angle in the longitudinal direction, no more than two wires 22 are placed in each ribless region 18. This allows for even expansion of blood vessels even in the bent portion, and makes it possible to create cracks or ruptures at multiple circumferential locations in the calcified lesion.

[0067] Preferably, the convex ridge 21 is made of resin. This improves the conformability and passage performance of the balloon 10 in the curved sections of blood vessels. On the other hand, since the wire 22 is not fixed to the straight section 13, the wire 22 can move to an optimal position on the outer surface of the balloon 10 when passing through the curved section of the blood vessel, ensuring passage performance in the curved section regardless of the constituent material of the wire 22.

[0068] Preferably, the balloon body 16 and the ridge 21 are formed from the same material. More preferably, the balloon body 16 and the ridge 21 are integrally molded from the same material. This ensures the unity of the balloon body 16 and the ridge 21, making it possible to inflate the balloon 10 with a higher expansion pressure, and making it easier to effectively crack or rupture even highly calcified lesions.

[0069] It is preferable that the wire 22 is made of metal. If the wire 22 is made of metal, it becomes easier to press the wire 22 firmly against the inner surface of the lesion when the balloon 10 is expanded, making it easier to effectively crack or break even highly calcified lesions.

[0070] The ridge 21 and the wire 22 may have different cross-sectional shapes. Here, the cross-sectional shape refers to the cross-sectional shape perpendicular to the direction of extension of the ridge 21 or the wire 22. For example, it is preferable that the cross-sectional shape of the ridge 21 is a triangular or pentagonal shape with a pointed tip, and the cross-sectional shape of the wire 22 is circular, elliptical, or oblong. This makes it easier for the ridge 21 to bite into the lesion when the balloon 10 is expanded, and also prevents the wire 22 from damaging the inner wall of the blood vessel when the balloon 10 is delivered to the treatment area. The cross-sectional shape of the ridge 21 may be a semicircular or circular partial shape, and the cross-sectional shape of the wire 22 may be polygonal. In this case, when the balloon 10 is expanded, it is easier for the ridge 21 to push open the lesion, and when the wire 22 hits the inner surface of the lesion, stress tends to concentrate at the corners of the polygonal cross-section, making it easier to crack or break the calcified lesion.

[0071] The outer surface of the balloon 10 may contain a drug. In angioplasty, restenosis may occur in the narrowed area expanded by the balloon 10, but if a drug is provided on the outer surface of the balloon 10, the drug can be moved to the inner wall of the body cavity, such as the blood vessel wall, by expanding the balloon 10 at the narrowed area of ​​the blood vessel, thereby reducing the frequency of restenosis.

[0072] The drugs are not particularly limited as long as they are pharmacologically active substances, and include, for example, gene therapy drugs, non-gene therapy drugs, small molecules, cells, and other drugs that are accepted as pharmaceuticals. In particular, when catheters are used to suppress restenosis of blood vessels after treatment in angioplasty, anti-restenotic agents such as antiproliferative agents and immunosuppressants can be preferably used as drugs. Examples of such drugs include paclitaxel, sirolimus (rapamycin), everolimus, and zotarolimus.

[0073] When the balloon 10 is delivered to the treatment area, such as a narrowed blood vessel, it is preferable that it be inserted into the guiding catheter or sheath in a deflated state. In this case, it is preferable that the balloon 10 is appropriately folded so that its radial size is reduced.

[0074] Figures 7 to 9 show an example of the balloon 10 shown in Figure 4 being deflated and folded. As shown in Figures 7 to 9, in the deflated state of the balloon 10, the straight tube portion 13 has a folded wing portion 19 formed by folding it back at the convex-free region 18 with the inner surface of the balloon 10 facing inward, and it is preferable that the folded wing portion 19 is arranged to overlap the outer surface of the balloon 10. The folded wing portion 19 is formed when the straight tube portion 13 is folded back at the fold line 20 of the convex-free region 18, and the convex-free region 18 overlaps. It is preferable that the folded wing portion 19 is formed without including the convex-present region 17. At the fold line 20, the balloon 10 is folded back with the inner surface of the balloon body portion 16 facing inward. Therefore, when viewed from the outside of the balloon 10, the fold line 20 is formed as a mountain fold.

[0075] At the fold line 20, the balloon body portion 16 may be folded back so as to form a clear crease, or its tip may be folded back in a rounded shape. Since the balloon body portion 16 usually has a certain thickness and elasticity, the tip of the balloon body portion 16 is folded back in a rounded shape at the fold line 20. In this case, the folded tip of the balloon body portion 16 becomes the fold line 20.

[0076] The folding line 20 is preferably formed to extend parallel to the longitudinal axis or diagonally with respect to the longitudinal axis. Furthermore, it is preferable that a plurality of folding fin portions 19 are provided on the outer surface of the balloon 10. By forming the folding fin portions 19 in this way, it becomes easier to fold the balloon 10 compactly. The folding line 20 is preferably formed on the outer surface of the straight tube portion 13 at an angle of ±30° or less with respect to the longitudinal axis, but it may also be at an angle of ±20° or less or ±15° or less.

[0077] In the region 18 where no convex ridges exist, a fold line (a valley fold line when viewed from the outside of the balloon 10) may be formed on one and / or the other side in the circumferential direction of the fold line 20, with the outer surface of the balloon 10 facing inward. In this case, it is preferable that the fold line that becomes the valley fold line forms the base of the folded wing portion 19.

[0078] The multiple folding fin portions 19 may be arranged on the outer surface of the balloon 10 such that all of them collapse to one side in the circumferential direction, or some of the folding fin portions 19 may be arranged on the outer surface of the balloon 10 such that they collapse to one side in the circumferential direction, and the other folding fin portions 19 may be arranged on the outer surface of the balloon 10 such that they collapse to one side in the circumferential direction. In Figures 7 and 8, the folding fin portions 19 are arranged on the outer surface of the balloon 10 in the former configuration, and in Figure 9, the folding fin portions 19 are arranged on the outer surface of the balloon 10 in the latter configuration.

[0079] In one embodiment, as shown in Figure 7, the folded wing portion 19 may be arranged to cover the wire 22 when the balloon 10 is in a deflated state. In this case, when the balloon 10 is delivered to the treatment area, the wire 22 is less likely to get caught on the inner surface of the guiding catheter or the inner wall of the blood vessel, thereby improving the delivery of the balloon 10.

[0080] As shown in Figures 8 and 9, when the balloon 10 is deflated, the wire 22 may be positioned radially outward of the folded wing portion 19. In this case, when the balloon 10 is expanded in the narrowed portion of the blood vessel, the wire 22 is more easily pushed out radially outward by the ribless region 18, and the wire 22 is more easily pressed against the inner surface of the lesion.

[0081] In the deflated state of the balloon 10, the folding fin portion 19 may be positioned to cover the top 21A of the convex 21 as shown in Figure 7, or it may be positioned not to cover the top 21A of the convex 21 as shown in Figures 8 and 9. Although not shown in the drawings, in the deflated state of the balloon 10, the folding fin portion 19 may be positioned not to cover the top 21A of the convex 21 and the wire 22, or it may cover the top 21A of the convex 21 with the wire 22 positioned radially outward from the folding fin portion 19.

[0082] In the deflated state of the balloon 10, it is preferable that no more than two wires 22 are placed in each ridge-free region 18. This ensures that when the balloon 10 is expanded, no more than two wires 22 are placed in each ridge-free region 18.

[0083] This application claims the benefit of priority based on Japanese Patent Application No. 2025-051851, filed on 26 March 2025. The entire specification of Japanese Patent Application No. 2025-051851, filed on 26 March 2025, is incorporated herein by reference.

[0084] 1: Balloon catheter 2: Shaft 3: Inner shaft 4: Outer shaft, 4A: Proximal outer shaft, 4B: Distal outer shaft 5: Hub 6: Fluid injection section 7: Guidewire port 8: Tip 9: Radiopaque marker 10: Balloon 11: Proximal sleeve section 12: Proximal tapered section 13: Straight section 14: Distal tapered section 15: Distal sleeve section 16: Balloon body 17: Area with protrusions 18: Area without protrusions 19: Folding fin section 20: Folding line 21: Protrusion, 21A: Top, 21B: Base 22: Wire

Claims

1. A balloon catheter equipped with a balloon, wherein the balloon has a longitudinal axis direction extending from the proximal to the distal side, and a radial and circumferential direction perpendicular to the longitudinal axis direction, and comprises a straight tube portion, a proximal tapered portion located proximal to the straight tube portion, and a distal tapered portion located distal to the straight tube portion, the balloon has a convex ridge projecting outward in the radial direction on its outer surface, a plurality of such convex ridges are provided in the circumferential direction of the straight tube portion, and a plurality of convex ridge-present regions and a plurality of convex ridge-absent regions are formed on the outer surface of the straight tube portion, the number of layers in the layer structure (including a single-layer structure) of the balloon in the plurality of convex ridge-absent regions is the same, and the balloon is a balloon catheter in which a wire not fixed to the straight tube portion is arranged on the radially outward side of the convex ridge-absent region.

2. The balloon catheter according to claim 1, wherein, in the vertical cross section of the straight tube portion in the longitudinal direction, at least one pair of ribs arranged adjacent to each other in the circumferential direction are spaced apart at an angle of 30° to 150° with respect to the longitudinal axis center of the balloon, and the wire is arranged between the pair of ribs.

3. In the vertical cross-section of the straight tube portion in the longitudinal direction, the plurality of protrusions are arranged such that adjacent protrusions in the circumferential direction are spaced apart from each other at an angle of 30° to 150° with respect to the longitudinal axis center of the balloon, as described in claim 1.

4. The balloon catheter according to claim 1, wherein the balloon has a proximal sleeve portion located proximal to the proximal tapered portion and a distal sleeve portion located distal to the distal tapered portion, the proximal end of the wire is fixed to the proximal sleeve portion and / or the proximal tapered portion, and the distal end of the wire is fixed to the distal sleeve portion and / or the distal tapered portion.

5. The balloon catheter according to claim 1, wherein the convex ridge is made of resin.

6. The balloon catheter according to claim 1, wherein the balloon has a balloon body and a protrusion projecting radially outward from the outer surface of the balloon body, and the balloon body and the protrusion are formed from the same material.

7. The balloon catheter according to claim 1, wherein the wire is made of metal.

8. The balloon catheter according to claim 1, wherein the cross-sectional shape of the convex ridge and the cross-sectional shape of the wire are different from each other.

9. The balloon catheter according to claim 1, wherein two or more of the wires are not arranged in each of the plurality of regions where no convex ridges exist.

10. The balloon catheter according to any one of claims 1 to 9, wherein, in the deflated state of the balloon, the straight tube portion is folded back at the region where the convex ridge is absent, with the inner surface of the balloon facing inward, and the regions where the convex ridge is absent overlap, and the folded wing portion is positioned to overlap the outer surface of the balloon and cover the wire.

11. In the deflated state of the balloon, the straight tube portion is folded back at the region where the convex ridge is absent, with the inner surface of the balloon facing inward, and has a folded wing portion where the regions where the convex ridge is absent overlap, the folded wing portion is arranged to overlap the outer surface of the balloon, and the wire is arranged on the radially outward side of the folded wing portion.

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