Balloon for balloon catheter and balloon catheter

Abstract

In a cross section perpendicular to the longitudinal axis direction (x) of a balloon (10) for a balloon catheter, the cross-sectional shape of a straight tubular portion (23) has at least one protruding part (30) protruding toward the outside of the balloon (10) and at least one recessed part (40) recessed toward the inside of the balloon (10). The protruding part (30) has a vertex (P2), which is a point of which the distance (D1) from the centroid (P1) of the cross-sectional shape of the straight tubular portion (23) is maximal. The recessed part (40) is not present on a straight line (L1) connecting the vertex (P2) and the centroid (P1) of the cross-sectional shape of the straight tubular portion (23).

Description

Balloons and balloon catheters for balloon catheters

[0001] This disclosure relates to a balloon for a balloon catheter and a balloon catheter equipped with said balloon.

[0002] Angina pectoris and myocardial infarction can occur when narrowed areas form on the inner wall of blood vessels due to hardening caused by calcification. One treatment for these conditions is angioplasty, which uses a balloon catheter to widen the narrowed area. Angioplasty is a minimally invasive treatment that does not require open-heart surgery like bypass surgery and is widely performed.

[0003] A balloon catheter is inserted into a body cavity with the balloon deflated and delivered through the cavity to the treatment site. During delivery, the balloon's movement is controlled by transmitting operations from the proximal end to the tip where the balloon is located. In angioplasty, the balloon is delivered to the stenosis, the treatment site, and then expanded to dilate the stenosis. After that, the expanded balloon is deflated and the balloon catheter is withdrawn from the body cavity. If the stenosis is not sufficiently dilated, the balloon catheter is reinserted to deliver the balloon to the treatment site, and the balloon is expanded to dilate the stenosis.

[0004] For example, Patent Document 1 discloses a balloon catheter having a balloon at the tip of the catheter, wherein the cross-sectional shape of the balloon perpendicular to the catheter axis has multiple radially arranged protrusions. Patent Document 2 discloses a balloon catheter having multiple inclined wings formed at the distal end of the shaft, each of which is inclined at an angle of approximately 15 to approximately 75 degrees from the tangent to an inner tubular member extending through the wings. Patent Document 3 discloses a method for manufacturing a catheter balloon, in which a balloon tube is placed in a mold having a cavity for shaping the balloon, with multiple grooves and an equal number of corresponding protrusions extending over at least a portion of the longitudinal direction of the cavity, and the tube is heated and pressurized to make it adhere tightly to the inner wall surface of the mold, thereby obtaining a balloon in which multiple longitudinal grooves and an equal number of corresponding wing portions are formed in at least a portion of the longitudinal direction. Patent Document 4 discloses a medical catheter balloon in which, when the balloon is pressurized at 0.6 atmG, the balloon cross section perpendicular to the longitudinal axis of the catheter has at least three to six corners, the corners are formed continuously from the distal end of the distal balloon taper to the proximal end of the proximal balloon taper, and when the balloon is expanded at 6 atmG, the cross-sectional shape of at least the straight section is substantially circular. Patent Document 5 discloses a medical balloon in which, in a stationary state, at least the main body of the balloon has a plurality of concave lateral regions extending between a first tapered section and a second tapered section, each concave lateral region curving toward the longitudinal axis of the balloon, and the main body has at least one layer extending around the entire circumference when viewed in a radial cross-section, each layer being formed from a substantially homogeneous polymer material.Patent Document 6 discloses a method for forming a medical balloon, which includes the steps of placing a balloon preform within a first mold, the first mold having an internal cavity, the radial cross-section of the internal cavity of the first mold being defined by a first outer periphery; and placing a preformed balloon within a second mold, the second mold having an internal cavity, the radial cross-section of the internal cavity of the second mold being defined by a second outer periphery that is larger than the first outer periphery of the first mold. It is disclosed that the body region of the second mold has a configuration with a plurality of wings.

[0005] Japanese Patent Application Laid-Open No. 08-112351, International Publication No. 1999 / 055406, Japanese Patent Application Laid-Open No. 2003-062080, Japanese Patent Application Laid-Open No. 2005-323714, International Publication No. 2007 / 055732, International Publication No. 2008 / 027088

[0006] In the above conventional balloon, when it is expanded and then contracted, the balloon membrane is folded to form a blade-shaped portion. However, the blade-shaped portion was likely to be in a state of greatly expanding in the radial direction. If the blade-shaped portion greatly expands during the contraction of the balloon, there is a risk of damaging the wall of a living body lumen such as a blood vessel, and the blade-shaped portion is likely to catch on the wall of the living body lumen or an implant in the living body lumen such as a stent placed in the living body lumen, resulting in a decrease in the permeability of the balloon in the living body lumen and the possibility that the procedure cannot be performed quickly. Therefore, there was room for improvement.

[0007] In view of the above circumstances, the present disclosure aims to solve the problem of providing a balloon for a balloon catheter that can be easily folded so that its outer diameter becomes smaller when the balloon is contracted after expansion, is less likely to damage the wall of a living body lumen, and can improve the insertion performance in the living body lumen, and a balloon catheter including the balloon.

[0008] A balloon for a balloon catheter and a balloon catheter equipped with the balloon according to the embodiment of the present disclosure that has been able to solve the above problems is as follows: [1] A balloon for a balloon catheter having a longitudinal axis direction extending from the proximal side to the distal side, and a radial direction and a circumferential direction perpendicular to the longitudinal axis direction, wherein the balloon 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, wherein in a cross section perpendicular to the longitudinal axis direction, the cross-sectional shape of the straight tube portion has at least one convex portion projecting outward from the balloon and at least one concave portion recessed inward from the balloon, wherein in a cross section perpendicular to the longitudinal axis direction, the convex portion has a vertex which is the point at which the distance from the centroid of the cross-sectional shape of the straight tube portion is greatest, and wherein in a cross section perpendicular to the longitudinal axis direction, the concave portion does not lie on a straight line connecting the centroid of the cross-sectional shape of the straight tube portion and the vertex. [2] In a cross section perpendicular to the longitudinal axis, the outer edge of the convex portion has one end in the circumferential direction and the other end opposite to the one end in the circumferential direction, and in a cross section perpendicular to the longitudinal axis, the length from the vertex on the outer edge of the straight tube portion to the one end is shorter than the length from the vertex on the outer edge of the straight tube portion to the other end, as described in [1]. [3] In a cross section perpendicular to the longitudinal axis of the straight tube portion, the outer edge of the convex portion has a curved portion including the vertex, a first straight portion including the one end, and a second straight portion including the other end, as described in [2]. [4] In a cross section perpendicular to the longitudinal axis of the straight tube portion, the length of the first straight portion is shorter than the length of the second straight portion, as described in [3].[5] The number of protrusions is multiple, and the multiple protrusions include a first protrusion and a second protrusion adjacent to the first protrusion in the circumferential direction, and in a cross section perpendicular to the longitudinal axis direction of the straight pipe section, the outer edge of the first protrusion has one end of the first protrusion in the circumferential direction, the other end of the first protrusion opposite to the one end of the first protrusion in the circumferential direction, a curved portion including the vertex of the first protrusion, a first straight portion including the one end of the first protrusion, and a second straight portion including the other end of the first protrusion, and in a cross section perpendicular to the longitudinal axis direction of the straight pipe section, the outer edge of the second protrusion has one end of the second protrusion in the circumferential direction, the other end of the second protrusion opposite to the one end of the second protrusion in the circumferential direction, a curved portion including the vertex of the second protrusion, a first straight portion including the one end of the second protrusion, and a second straight portion including the other end of the second protrusion, A balloon for a balloon catheter according to any one of [1] to [4], wherein the angle between the second linear portion of the first protrusion and the first linear portion of the second protrusion is less than 180 degrees. [6] A balloon for a balloon catheter according to any one of [1] to [5], 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, and the cross-sectional shapes of the proximal sleeve portion and the distal sleeve portion perpendicular to the longitudinal axis are circular. [7] A balloon catheter comprising a balloon for a balloon catheter according to any one of [1] to [6].

[0009] According to the balloon for the balloon catheter described above, the cross-sectional shape of the straight tube portion has at least one convex portion and at least one concave portion. The convex portion has a vertex at the point where the distance from the centroid of the cross-sectional shape of the straight tube portion is greatest, and the concave portion does not lie on the straight line connecting the centroid of the cross-sectional shape of the straight tube portion and the vertex. As a result, when the balloon is deflated after being expanded, the convex portion becomes a wing-shaped portion, making the balloon easy to fold, and the wing-shaped portion tends to be inclined along the circumferential direction of the balloon. Consequently, it is possible to create a balloon that is easy to fold so that the outer diameter becomes smaller when the balloon is deflated.

[0010] This figure shows a side view of a balloon in its expanded state according to one embodiment of the present disclosure. This figure shows a cross-sectional view of the balloon shown in Figure 1, taken along the line II-II. This figure shows a cross-sectional view of the balloon shown in Figure 2, taken along the line IV-IV. This figure shows a cross-sectional view of the balloon shown in Figure 1, taken along the line V-V. This figure shows a cross-sectional view of the straight tube portion of a balloon in its expanded state according to another embodiment of the present disclosure, perpendicular to the longitudinal axis. This figure shows a side view of a balloon catheter having the balloon shown in Figure 1.

[0011] The contents of this disclosure will be described below based on embodiments, but 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 statements, 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.

[0012] The balloon for a balloon catheter according to the embodiment of the present disclosure is a balloon for a balloon catheter having 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, wherein the balloon 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, wherein in a cross section perpendicular to the longitudinal axis direction, the cross-sectional shape of the straight tube portion has at least one convex portion projecting outward from the balloon and at least one concave portion recessed inward from the balloon, wherein in a cross section perpendicular to the longitudinal axis direction, the convex portion has a vertex which is the point where the distance from the centroid of the cross-sectional shape of the straight tube portion is greatest, and in a cross section perpendicular to the longitudinal axis direction, the concave portion does not lie on a straight line connecting the centroid of the cross-sectional shape of the straight tube portion and the vertex.

[0013] Hereinafter, a balloon for a balloon catheter according to an embodiment of this disclosure will be described with reference to Figures 1 to 7. Figure 1 is a side view of the balloon. Figure 2 is a cross-sectional view of the balloon shown in Figure 1, taken along the line II-II, showing a cross-sectional view perpendicular to the longitudinal axis at the straight section of the balloon. Figure 3 shows a cross-sectional view perpendicular to the longitudinal axis in the deflated state of the balloon shown in Figure 2. Figure 4 is a cross-sectional view of the balloon shown in Figure 1, taken along the line IV-IV, showing a cross-sectional view perpendicular to the longitudinal axis at the proximal sleeve section of the balloon. Figure 5 is a cross-sectional view of the balloon shown in Figure 1, taken along the line V-V, showing a cross-sectional view perpendicular to the longitudinal axis at the distal sleeve section of the balloon. Figure 6 is a cross-sectional view perpendicular to the longitudinal axis at the straight section of a balloon in the expanded state according to another embodiment of this disclosure. Figure 7 is a side view of a balloon catheter having the balloon shown in Figure 1.

[0014] As shown in Figure 1, the balloon 10 according to this disclosure is a balloon 10 for a balloon catheter 1 having a longitudinal axis direction x extending from the proximal to the distal side, and a radial direction y and a circumferential direction z perpendicular to the longitudinal axis direction x. In this specification, the balloon for a balloon catheter may be simply referred to as "balloon".

[0015] The longitudinal axis direction x is the direction along the longitudinal axis of the balloon 10 (i.e., the central axis in the longitudinal direction). The radial direction y is the direction perpendicular to the longitudinal axis direction x. The radial direction y refers to the radial direction of the balloon 10, where inward in the radial direction y refers to the direction toward the longitudinal axis of the balloon 10, and outward in the radial direction y refers to the direction extending radially from the longitudinal axis in the longitudinal direction, opposite to the inward direction. The circumferential direction z refers to the direction around the longitudinal axis of the balloon 10, i.e., the direction along the outer circumference of the balloon 10. In this specification, the direction toward the user's hand in the longitudinal axis direction x is referred to as the proximal side, and the direction opposite to the proximal side, i.e., toward the person being treated, is referred to as the distal side. Furthermore, when each member or part is divided into two equal parts along the longitudinal axis direction x of the balloon 10, the part located on the distal side of each member or part is referred to as the distal part of each member or part, and the part located on the proximal side of each member or part is referred to as the proximal part of each member or part. The distal end of each member or part is the end located furthest distal to the member or part. The proximal end of each member or part is the end located furthest proximal to the member or part. The term "end" includes the surrounding area of ​​the end. That is, the distal end refers to the distal end and the surrounding area of ​​the distal end, and the proximal end refers to the proximal end and the surrounding area of ​​the proximal end.

[0016] Other components and parts also have longitudinal axis directions, radial directions, and circumferential directions, which may or may not be the same as the longitudinal axis direction x, radial direction y, and circumferential direction z of the balloon 10. However, for the sake of clarity, in this specification, all components and parts are described as having the same longitudinal axis direction x, radial direction y, and circumferential direction z as the balloon 10.

[0017] The balloon 10 is located at the distal end of the balloon catheter 1. The balloon 10 can be expanded by introducing fluid into its lumen, and the balloon 10 can be deflated by expelling fluid from its lumen.

[0018] The dilation of a stenotic area using the balloon catheter 1 is performed by inserting the balloon 10, located at the distal end of the balloon catheter 1, into the lumen of the blood vessel, delivering it to the stenotic area, and then inflating the balloon 10. When inserting the balloon 10 into the stenotic area or when removing the balloon 10 from the body, the fluid is discharged from the lumen of the balloon 10 to cause it to deflate, and the outer diameter of the balloon 10 can be reduced by wrapping the wing-shaped portion of the balloon 10 around the shaft 140 of the balloon catheter 1.

[0019] As shown in Figure 1, the balloon 10 has a straight tube section 23, a proximal tapered section 22 located proximal to the straight tube section 23, and a distal tapered section 24 located distal to the straight tube section 23.

[0020] The straight tube portion 23 is preferably a substantially columnar shape with approximately the same diameter in the longitudinal axis x when the balloon 10 is expanded, but it may have different diameters in the longitudinal axis x. The proximal tapered portion 22 and the distal tapered portion 24 are preferably formed in a substantially conical or frustoconical shape, decreasing in diameter as they move away from the straight tube portion 23 when the balloon 10 is expanded. When the balloon 10 is expanded, the straight tube portion 23 has the maximum diameter, so when the balloon 10 is expanded in a lesion such as a stenosis, the straight tube portion 23 can sufficiently contact the lesion, making it easier to perform treatment such as dilation of the lesion. Also, when the balloon 10 is expanded, the proximal tapered portion 22 and the distal tapered portion 24 are reduced in diameter, so when the balloon 10 is deflated, the outer diameters of the proximal and distal ends of the balloon 10 can be easily reduced. In addition, the step difference between the shaft 140 of the balloon catheter 1 and the balloon 10 can be reduced, making it easier to insert the balloon 10 into the body cavity.

[0021] As shown in Figure 1, it is preferable that the balloon 10 further includes a proximal sleeve portion 21 located proximal to the proximal tapered portion 22 and a distal sleeve portion 25 located distal to the distal tapered portion 24. It is preferable that the proximal tapered portion 22, the straight tube portion 23, and the distal tapered portion 24 are parts that expand when fluid is introduced into the balloon 10, while the proximal sleeve portion 21 and the distal sleeve portion 25 are parts that do not expand. Because the proximal sleeve portion 21 and the distal sleeve portion 25 are parts that do not expand, it is possible to firmly fix at least a part of the proximal sleeve portion 21 and at least a part of the distal sleeve portion 25 to a member such as the shaft 140.

[0022] Examples of materials that make up the balloon 10 include polyamide resins such as nylon 11 and nylon 12, polyamide elastomers, polyolefin resins such as polyethylene, polypropylene, and ethylene-propylene copolymers, polyester resins such as polyethylene terephthalate, polyester elastomers, and polybutylene terephthalate, polyurethane resins such as polyurethane resins and polyurethane elastomers, thermoplastic elastomers such as polyether block amide copolymers, fluororesins, silicone resins, and natural rubbers such as latex rubber. These may be used individually or in combination of two or more.

[0023] The balloon 10 may have a single-layer structure, but it is preferable that it has a multilayer structure. If the balloon 10 has a multilayer structure, it is preferable that the balloon 10 has at least a first layer and a second layer laminated on the first layer. In other words, if the balloon 10 has a multilayer structure, the balloon 10 may consist of a first layer and a second layer, or it may further have a first layer, a second layer, and another layer different from the first and second layers.

[0024] In particular, it is preferable that the balloon 10 has a multilayer structure having a first layer and a second layer, with the material constituting the first layer being polyamide and the material constituting the second layer being an elastomer resin such as a polyether ester amide elastomer or a polyamide ether elastomer. Having a first layer and a second layer in the balloon 10, with the material constituting the first layer being polyamide and the material constituting the second layer being an elastomer resin, makes it easier to manufacture a thin-film and flexible balloon 10.

[0025] If the balloon 10 has a first layer and a second layer, and the material constituting the first layer is polyamide and the material constituting the second layer is elastomer resin, it is preferable that the first layer is located radially outward y than the second layer. In other words, it is preferable that the first layer is the outer layer and the second layer is the inner layer. When the balloon 10 is expanded, stress tends to be applied more easily to the inner layer than to the outer layer. Because the first layer is located radially outward y than the second layer, the second layer, which is the inner layer, becomes more flexible than the first layer, which is the outer layer. Therefore, when the balloon 10 is pressurized to expand it, the second layer can sufficiently withstand the stress generated by the pressurization, and the balloon 10 can be made highly pressure resistant.

[0026] The balloon 10 can be obtained by biaxial stretching or blow molding of a parison. The parison is a cylindrical member made of resin with a lumen. Like the balloon 10, the parison has a longitudinal axis x, a radial direction y, and a circumferential direction z. The parison can be obtained, for example, by extruding resin using a mold having a cylindrical shape. If the balloon 10 has a multilayer structure comprising a first layer and a second layer, the parison may be manufactured by co-extrusion molding, in which the materials constituting the first layer and the second layer are extruded simultaneously.

[0027] As shown in Figure 2, in a cross-section perpendicular to the longitudinal axis x, the cross-sectional shape of the straight pipe section 23 has at least one convex portion 30 protruding outward from the balloon 10 and at least one concave portion 40 recessed inward from the balloon 10. Preferably, the convex portion 30 is located at a different position from the concave portion 40 in the circumferential direction z. The convex portion 30 is the portion of the outer edge of the straight pipe section 23 in a cross-section perpendicular to the longitudinal axis x that protrudes outward from the balloon 10 in the radial direction y when the balloon 10 is expanded. The concave portion 40 is the portion of the outer edge of the straight pipe section 23 in a cross-section perpendicular to the longitudinal axis x that recesses inward from the balloon 10 in the radial direction y when the balloon 10 is expanded. The outer edge of the straight pipe section 23 refers to the contour line of the straight pipe section 23 in a cross-section perpendicular to the longitudinal axis x.

[0028] Because the cross-sectional shape of the straight tube section 23 has at least one convex portion 30 and at least one concave portion 40, as shown in Figure 3, when the balloon 10 is deflated, the convex portion 30 can easily form a wing-shaped portion 11, and the concave portion 40 can easily form a portion that is not a wing-shaped portion 11. Therefore, it is possible to easily control the location where the wing-shaped portion 11 is formed when the balloon 10 is deflated.

[0029] In a cross-section perpendicular to the longitudinal axis x, it is preferable that the number of protrusions 30 in the cross-sectional shape of the straight pipe section 23 is multiple. When the number of protrusions 30 in the cross-sectional shape of the straight pipe section 23 is multiple, it is preferable that a recess 40 is located between two adjacent protrusions 30 in the circumferential direction z. In other words, it is preferable that the recess 40 is the boundary between two adjacent protrusions 30 in the circumferential direction z.

[0030] In a cross-section perpendicular to the longitudinal axis x, the number of protrusions 30 in the cross-sectional shape of the straight tube section 23 is preferably 2 or more, and more preferably 3 or more. By setting the lower limit of the number of protrusions 30 in the cross-sectional shape of the straight tube section 23 within the above range, the outer diameter of the balloon 10 becomes smaller when the balloon 10 is deflated and the fin-shaped section 11 is folded. Furthermore, the number of protrusions 30 in the cross-sectional shape of the straight tube section 23 is preferably 10 or less, more preferably 8 or less, even more preferably 6 or less, and even more preferably 4 or less. By setting the upper limit of the number of protrusions 30 in the cross-sectional shape of the straight tube section 23 within the above range, the number of fin-shaped sections 11 formed by deflating the balloon 10 does not become too large, and the fin-shaped sections 11 can be easily folded along the circumferential direction z. Among these, the most preferable is that the number of protrusions 30 in the cross-sectional shape of the straight tube section 23 in a cross-section perpendicular to the longitudinal axis x is 3.

[0031] Furthermore, it is preferable that the number of recesses 40 in the cross-sectional shape of the straight pipe section 23 in a cross-section perpendicular to the longitudinal axis x is multiple. In particular, it is preferable that the number of protrusions 30 in the cross-sectional shape of the straight pipe section 23 in a cross-section perpendicular to the longitudinal axis x is multiple and the same as the number of recesses 40 in the cross-sectional shape of the straight pipe section 23. By having multiple protrusions 30 in the cross-sectional shape of the straight pipe section 23 and the same as the number of recesses 40, multiple wing-shaped portions 11 are more easily formed when the balloon 10 is deflated, making it easier to fold the balloon 10 so that its outer diameter is reduced.

[0032] In a cross-section perpendicular to the longitudinal axis x, if the cross-sectional shape of the straight pipe section 23 has multiple protrusions 30, the size and shape of the multiple protrusions 30 in the longitudinal axis x, radial direction y, and circumferential direction z may be the same or different. Also, in a cross-section perpendicular to the longitudinal axis x, if the cross-sectional shape of the straight pipe section 23 has multiple recesses 40, the size and shape of the multiple recesses 40 in the longitudinal axis x, radial direction y, and circumferential direction z may be the same or different.

[0033] As shown in Figure 2, in a cross-section perpendicular to the longitudinal axis x, the outer edge of the convex portion 30 has a vertex P2 which is the point where the distance D1 from the centroid P1 of the cross-sectional shape of the straight pipe portion 23 is greatest, and in a cross-section perpendicular to the longitudinal axis x, the concave portion 40 does not lie on the straight line L1 connecting the centroid P1 of the cross-sectional shape of the straight pipe portion 23 and the vertex P2. In other words, in a cross-section perpendicular to the longitudinal axis x when the balloon 10 is in its expanded state, the concave portion 40 does not lie on the straight line L1 connecting the centroid P1 of the cross-sectional shape of the straight pipe portion 23 and the vertex P2.

[0034] The vertex P2 is located on the outer edge of the convex portion 30 in a cross-section perpendicular to the longitudinal axis x when the balloon 10 is expanded, and refers to the point on the outer edge of the convex portion 30 that is furthest from the centroid P1 of the cross-sectional shape of the straight pipe portion 23. The fact that the recess 40 is not located on the straight line L1 connecting the centroid P1 of the cross-sectional shape of the straight pipe portion 23 and the vertex P2 means that, in the expanded state of the balloon 10, the portion on the outer edge of the straight pipe portion 23 corresponding to the recess 40 in a cross-section perpendicular to the longitudinal axis x does not overlap with the straight line L1.

[0035] In a cross-section perpendicular to the longitudinal axis x, the recess 40 does not lie on a straight line L1. As shown in Figure 3, when the balloon 10 is deflated after expansion, the wing-shaped portion 11 formed is tilted along the circumferential direction z of the balloon 10, making it easier to collapse. Therefore, the balloon 10 can be easily folded to reduce its outer diameter when it is deflated.

[0036] Furthermore, when the balloon 10 is molded by blow molding, the fact that the recess 40 does not lie on a straight line L1 in a cross section perpendicular to the longitudinal axis x means that the recess 40 is less likely to obstruct the process of blowing gas into the parison placed in the lumen of the mold to make the parison adhere to the mold. Specifically, when the parison adheres to the inner wall surface defining the lumen of the mold, the resin constituting the parison can more easily reach the tip of the protrusion 30 without being obstructed by the recess 40. As a result, the moldability of the balloon 10 can be improved.

[0037] In a cross-section perpendicular to the longitudinal axis x, it is preferable that the cross-sectional shape of the straight tube section 23 and the cross-sectional shape of at least one of the proximal tapered section 22 and the distal tapered section 24 have a convex portion 30 and a concave portion 40. By having a convex portion 30 and a concave portion 40 not only in the straight tube section 23 of the balloon 10 but also in at least one of the proximal tapered section 22 and the distal tapered section 24, the proximal tapered section 22 and the distal tapered section 24 become easier to fold when the balloon 10 is deflated, making it easier to reduce the outer diameter of the balloon 10 when it is deflated.

[0038] Preferably, not only in the straight tube portion 23 of the balloon 10, but also in at least one of the proximal tapered portion 22 and the distal tapered portion 24, in a cross section perpendicular to the longitudinal axis x, the convex portion 30 has a vertex P2, and the concave portion 40 does not lie on a straight line connecting the centroid of at least one of the cross-sectional shapes of the proximal tapered portion 22 and the distal tapered portion 24 to the vertex P2. By not having the concave portion 40 on a straight line L1 in the straight tube portion 23 of the balloon 10, but also in at least one of the proximal tapered portion 22 and the distal tapered portion 24, the wing-shaped portions 11 formed in the proximal tapered portion 22 and the distal tapered portion 24 become more likely to collapse along the circumferential direction z when the balloon 10 is deflated, making it easier to fold the balloon 10 so that its outer diameter becomes smaller, and also making it easier to shape the balloon 10 as a whole in the longitudinal axis x, thereby improving productivity.

[0039] As shown in Figure 2, in a cross-section perpendicular to the longitudinal axis x, the outer edge of the convex portion 30 has one end 31 in the circumferential direction z and the other end 32 on the opposite side of the circumferential direction z from the one end 31. Here, one end 31 refers to the outermost point on one side of the outer edge of the convex portion 30 in the circumferential direction z, and the other end 32 refers to the outermost point on the other side of the outer edge of the convex portion 30 in the circumferential direction z. In a cross-section perpendicular to the longitudinal axis x, it is preferable that the length D2 between the vertex P2 on the outer edge of the straight pipe portion 23 and one end 31 is shorter than the length D3 between the vertex P2 on the outer edge of the straight pipe portion 23 and the other end 32. Because length D2 is shorter than length D3, the shape of the convex portion 30 in a cross-section perpendicular to the longitudinal axis x becomes asymmetric with respect to the straight line L1 connecting the centroid P1 of the cross-sectional shape of the straight pipe portion 23 and the vertex P2. As a result, when the balloon 10 is deflated and folded, the wing-shaped portion 11 is more likely to tilt to one side than to the other, making it easier to fold the balloon 10 so that its outer diameter is reduced.

[0040] In a cross-section perpendicular to the longitudinal axis x, the length D2 between the vertex P2 on the outer edge of the straight tube section 23 and one end 31 is preferably 90% or less, more preferably 80% or less, and even more preferably 70% or less, of the length D3 between the vertex P2 on the outer edge of the straight tube section 23 and the other end 32. By setting the upper limit of the ratio of length D2 to length D3 within the above range, the wing-shaped portion 11 can be made to fall to one side more easily when the balloon 10 is deflated and folded. Furthermore, in a cross-section perpendicular to the longitudinal axis x, the length D2 between the vertex P2 on the outer edge of the straight tube section 23 and one end 31 is preferably 10% or more, more preferably 20% or more, and even more preferably 30% or more, of the length D3 between the vertex P2 on the outer edge of the straight tube section 23 and the other end 32. By setting the lower limit of the ratio of length D2 to length D3 within the above range, the balloon 10 can be made to expand more easily in the radial direction y when expanded, resulting in a balloon 10 with high expansion force.

[0041] As shown in FIG. 2, in a cross-section perpendicular to the longitudinal axis direction x in the straight pipe portion 23, it is preferable that the outer edge of the convex portion 30 has a curved portion 33 including the vertex P2, a first linear portion 34 including one end 31, and a second linear portion 35 including the other end 32. That is, it is preferable that the convex portion 30 has a configuration including the first linear portion 34, the curved portion 33, and the second linear portion 35 in this order from one side to the other side.

[0042] The curved portion 33 includes the vertex P2 of the convex portion 30 and is a portion where the outer edge of the convex portion 30 in a cross-section perpendicular to the longitudinal axis direction x in the straight pipe portion 23 is curved. The first linear portion 34 includes one end 31 of the convex portion 30 and is a portion where the outer edge of the convex portion 30 in a cross-section perpendicular to the longitudinal axis direction x in the straight pipe portion 23 is linear. The second linear portion 35 includes the other end 32 of the convex portion 30 and is a portion where the outer edge of the convex portion 30 in a cross-section perpendicular to the longitudinal axis direction x in the straight pipe portion 23 is linear.

[0043] The convex portion 30 may further have a portion different from the curved portion 33, the first linear portion 34, and the second linear portion 35, or may be composed of the curved portion 33, the first linear portion 34, and the second linear portion 35. It is preferable that an end on one side of the curved portion 33 is connected to the first linear portion 34 and an end on the other side of the curved portion 33 is connected to the second linear portion 35.

[0044] Since the convex portion 30 has the curved portion 33, the first linear portion 34, and the second linear portion 35, the curved portion 33 is likely to form the tip of the blade-shaped portion 11, and the first linear portion 34 and the second linear portion 35 are likely to form the base of the blade-shaped portion 11. Therefore, it becomes easier to control the position where the base of the blade-shaped portion 11 is formed when the balloon 10 is contracted, and the balloon 10 can be made easily foldable so that the outer diameter becomes smaller.

[0045] As shown in Fig. 2, in a cross-section perpendicular to the longitudinal axis direction x in the straight pipe portion 23, it is preferable that the length D4 of the first linear portion 34 is shorter than the length D5 of the second linear portion 35. Since the length D4 is shorter than the length D5, in a cross-section perpendicular to the longitudinal axis direction x, the length on one side of the convex portion 30 becomes shorter than the length on the other side. Therefore, when the balloon 10 is contracted and folded, the blade-shaped portion 11 is likely to fall to one side, and it becomes easier to fold the balloon 10 so that the outer diameter of the balloon 10 becomes smaller.

[0046] In a cross-section perpendicular to the longitudinal axis direction x in the straight pipe portion 23, it is preferable that the length D4 of the first linear portion 34 is 90% or less of the length D5 of the second linear portion 35, more preferably 80% or less, and even more preferably 70% or less. By setting the upper limit value of the ratio between the length D4 and the length D5 within the above range, when the balloon 10 is contracted, the blade-shaped portion 11 can be easily made to fall to one side. Also, in a cross-section perpendicular to the longitudinal axis direction x in the straight pipe portion 23, it is preferable that the length D4 is 10% or more of the length D5, more preferably 20% or more, and even more preferably 30% or more. By setting the lower limit value of the ratio between the length D4 and the length D5 within the above range, when the balloon 10 expands, the balloon 10 can be easily expanded in the radial direction y, and it can be made easier to increase the expansion force of the balloon 10.

[0047] As shown in Fig. 2, the number of convex portions 30 is plural, and it is preferable that the plural convex portions 30 include a first convex portion 50 and a second convex portion 60 adjacent to the first convex portion 50 in the circumferential direction z. That is, in a cross-section perpendicular to the longitudinal axis direction x, it is preferable that the cross-sectional shape of the straight pipe portion 23 has a plurality of convex portions 30 including the first convex portion 50 and the second convex portion 60.

[0048] In a cross-section perpendicular to the longitudinal axis direction x in the straight pipe portion 23, the outer edge of the first convex portion 50 preferably has a curved portion 53 including one end 51 in the circumferential direction z, the other end 52 on the side opposite to the one end 51 of the first convex portion 50 in the circumferential direction z, the apex P3 of the first convex portion 50, a first linear portion 54 including the one end 51 of the first convex portion 50, and a second linear portion 55 including the other end 52 of the first convex portion 50.

[0049] The vertex P3 of the first protrusion 50 is located on the outer edge of the first protrusion 50 in the expanded state of the balloon 10 in a cross section perpendicular to the longitudinal axis x, and points to the point on the outer edge of the first protrusion 50 that is the greatest distance from the centroid P1 of the cross-sectional shape of the straight pipe section 23. The curved portion 53 includes the vertex P3 of the first protrusion 50 and is the portion of the outer edge of the first protrusion 50 in the cross section perpendicular to the longitudinal axis x of the straight pipe section 23 that is curved. The first straight portion 54 includes one end 51 of the first protrusion 50 and is the portion of the outer edge of the first protrusion 50 in the cross section perpendicular to the longitudinal axis x of the straight pipe section 23 that is straight. The second straight portion 55 includes the other end 52 of the first protrusion 50 and is the portion of the outer edge of the first protrusion 50 in the cross section perpendicular to the longitudinal axis x of the straight pipe section 23 that is straight.

[0050] Preferably, the first protrusion 50 has a configuration in which, from one side to the other, a first linear portion 54, a curved portion 53, and a second linear portion 55 in that order. The first protrusion 50 may further have portions different from the curved portion 53, the first linear portion 54, and the second linear portion 55, and may be composed of the curved portion 53, the first linear portion 54, and the second linear portion 55. Preferably, one end of the curved portion 53 is connected to the first linear portion 54, and the other end of the curved portion 53 is connected to the second linear portion 55.

[0051] In a cross-section perpendicular to the longitudinal axis x of the straight pipe section 23, it is preferable that the outer edge of the second protrusion 60 has one end 61 in the circumferential direction z, the other end 62 opposite to the one end 61 of the second protrusion 60 in the circumferential direction z, a curved portion 63 including the vertex P4 of the second protrusion 60, a first straight portion 64 including the one end 61 of the second protrusion 60, and a second straight portion 65 including the other end 62 of the second protrusion 60.

[0052] The vertex P4 of the second protrusion 60 is located on the outer edge of the second protrusion 60 in the expanded state of the balloon 10 in a cross section perpendicular to the longitudinal axis x, and points to the point on the outer edge of the second protrusion 60 that is furthest from the centroid P1 of the cross-sectional shape of the straight pipe section 23. The curved portion 63 includes the vertex P4 of the second protrusion 60 and is the portion of the straight pipe section 23 where the outer edge of the second protrusion 60 in a cross section perpendicular to the longitudinal axis x is curved. The first straight portion 64 includes one end 61 of the second protrusion 60 and is the portion of the straight pipe section 23 where the outer edge of the second protrusion 60 in a cross section perpendicular to the longitudinal axis x is straight. The second straight portion 65 includes the other end 62 of the second protrusion 60 and is the portion of the straight pipe section 23 where the outer edge of the second protrusion 60 in a cross section perpendicular to the longitudinal axis x is straight.

[0053] Preferably, the second protrusion 60 has a configuration in which, from one side to the other, a first linear portion 64, a curved portion 63, and a second linear portion 65 in that order. The second protrusion 60 may further have portions different from the curved portion 63, the first linear portion 64, and the second linear portion 65, and may be composed of the curved portion 63, the first linear portion 64, and the second linear portion 65. Preferably, one end of the curved portion 63 is connected to the first linear portion 64, and the other end of the curved portion 63 is connected to the second linear portion 65.

[0054] As shown in Figure 2, it is preferable that the angle θ1 between the second linear portion 55 of the first protrusion 50 and the first linear portion 64 of the second protrusion 60 is less than 180 degrees. The angle θ1 refers to the angle that the second linear portion 55 and the first linear portion 64 make outward from the balloon 10 in a cross section perpendicular to the longitudinal axis x. When the balloon 10 is deflated and folded, the other end 52 of the first protrusion 50 and the one end 61 of the second protrusion 60 tend to become valleys between two adjacent wing-shaped portions 11. Therefore, it becomes easier to control the position in which the wing-shaped portions 11 are formed when the balloon 11 is deflated.

[0055] The angle θ1 between the second linear portion 55 and the first linear portion 64 is preferably less than 180 degrees, more preferably 175 degrees or less, and even more preferably 170 degrees or less. Setting the upper limit of the angle θ1 within the above range makes it easier to control the position where the wing-shaped portion 11 is formed when the balloon 10 is contracted. Furthermore, the angle θ1 between the second linear portion 55 and the first linear portion 64 is preferably 90 degrees or more, more preferably 100 degrees or more, and even more preferably 110 degrees or more. Setting the lower limit of the angle θ1 within the above range makes it easier to increase the expansion force of the balloon 10 when the balloon 10 is expanded.

[0056] As shown in Figure 1, the balloon 10 further comprises a proximal sleeve portion 21 located proximal to the proximal tapered portion 22 and a distal tapered portion 24 located distal to the distal tapered portion 24. Preferably, the cross-sectional shape of the proximal sleeve portion 21 and the distal sleeve portion 25 perpendicular to the longitudinal axis x is circular. By having a circular cross-sectional shape of the proximal sleeve portion 21 and the distal sleeve portion 25 perpendicular to the longitudinal axis x, the outer surfaces of the proximal sleeve portion 21 and the distal sleeve portion 25, which are the non-expanding parts of the balloon 10 where the wing-shaped portion 11 is not formed, become smooth. Therefore, when pushing the balloon 10 distally and pulling the balloon 10 proximal to the proximal side, the proximal sleeve portion 21 and the distal sleeve portion 25 are less likely to be damaged even if they come into contact with other objects, resulting in a highly safe balloon 10.

[0057] As shown in Figure 6, in a cross section perpendicular to the longitudinal axis x, it is preferable that the average thickness of the balloon 10 in the convex portion 30 of the straight tube section 23 is smaller than the average thickness of the balloon 10 in the concave portion 40 of the straight tube section 23. In other words, in the straight tube section 23, it is preferable that the average thickness of the balloon 10 in the convex portion 30 is thinner than that of the balloon 10 in the concave portion 40. Because the average thickness of the balloon 10 in the convex portion 30 of the straight tube section 23 is smaller than the average thickness of the balloon 10 in the concave portion 40, the thickness of the balloon 10 in the portion that constitutes the wing-shaped portion 11 formed when the balloon 10 is deflated becomes thinner, so the wing-shaped portion 11 is less bulky. Therefore, it becomes easier to make a balloon 10 that is easy to fold so that the outer diameter of the balloon 10 is small.

[0058] In a cross-section perpendicular to the longitudinal axis x, the average film thickness of the balloon 10 in the convex portion 30 of the straight tube section 23 is preferably 90% or less, more preferably 85% or less, and even more preferably 80% or less, of the average film thickness of the balloon 10 in the recess 40 of the straight tube section 23. By setting the upper limit of the ratio between the average film thickness of the balloon 10 in the convex portion 30 of the straight tube section 23 and the average film thickness of the balloon 10 in the recess 40 to the above range, it becomes easier to reduce the film thickness of the balloon 10 in the portion constituting the wing-shaped portion 11, and the outer diameter of the balloon 10 can be reduced when the balloon 10 is deflated and folded. Furthermore, in a cross-section perpendicular to the longitudinal axis x, the average film thickness of the balloon 10 in the convex portion 30 of the straight tube section 23 is preferably 10% or more, more preferably 20% or more, even more preferably 30% or more, even more preferably 45% or more, and particularly preferably 60% or more, of the average film thickness of the balloon 10 in the recess 40 of the straight tube section 23. By setting the lower limit of the ratio between the average thickness of the balloon 10 in the convex portion 30 of the straight pipe section 23 and the average thickness of the balloon 10 in the concave portion 40 to the above range, the strength of the balloon 10 in the straight pipe section 23 can be maintained, resulting in a highly durable balloon 10.

[0059] A balloon catheter 1 according to an embodiment of this disclosure comprises a balloon 10 for the balloon catheter 1.

[0060] As shown in Figure 7, a balloon catheter 1 having a balloon 10 according to the embodiment of this disclosure preferably has a shaft 140. The balloon 10 is connected to the distal end of the shaft 140, and the balloon 10 can be expanded by introducing fluid through the lumen of the shaft 140 and deflated by expelling the fluid. To control the expansion and contraction of the balloon 10, an indeflerator (balloon pressurizer) can be used to introduce or expel fluid. The fluid can be, for example, physiological saline or a mixture of contrast agent and physiological saline. The fluid may also be a pressurized fluid pressurized by a pump or the like.

[0061] Figure 7 shows a so-called rapid exchange type balloon catheter 1, which has a guidewire port 150 located midway from the distal to the proximal end of the shaft 140, and an inner shaft 160 that functions as a guidewire insertion passage from the guidewire port 150 to the distal end of the shaft 140. Preferably, the balloon catheter 1 has a proximal shaft 141 and a distal shaft 142, and the proximal shaft 141 and the distal shaft 142 are separate components, and the proximal end of the distal shaft 142 is connected to the distal end of the proximal shaft 141, thereby forming a shaft 140 that extends from the balloon 10 to the proximal end of the balloon catheter 1. Alternatively, one shaft 140 may extend from the balloon 10 to the proximal end of the balloon catheter 1, and the proximal shaft 141 and the distal shaft 142 may be composed of multiple tubular members.

[0062] The shaft 140 preferably has a fluid channel and a guide wire insertion passage inside. To configure the shaft 140 to have a fluid channel and a guide wire insertion passage inside, for example, an inner shaft 160 located inside the shaft 140 may function as a guide wire insertion passage, and the space between the shaft 140 and the inner shaft 160 may function as a fluid channel. In such a configuration, it is preferable that the inner shaft 160 extends from the distal end of the shaft 140 and penetrates the balloon 10, with the distal portion of the balloon 10 connected to the inner shaft 160 and the proximal portion of the balloon 10 connected to the shaft 140.

[0063] The shaft 140 is preferably composed of resin, metal, or a combination of resin and metal. Using resin as a constituent material for the shaft 140 makes it easier to impart flexibility and elasticity to the shaft 140. Using metal as a constituent material for the shaft 140 can improve the delivery performance of the balloon catheter 1. Examples of resins that make up the shaft 140 include polyamide resins, polyester resins, polyurethane resins, polyolefin resins, fluororesins, vinyl chloride resins, silicone resins, natural rubber, synthetic rubber, etc. These may be used individually or in combination of two or more. Examples of metals that make up the shaft 140 include stainless steel such as SUS304 and SUS316, platinum, nickel, cobalt, chromium, titanium, tungsten, gold, Ni-Ti alloy, Co-Cr alloy, or combinations thereof. If the shaft 140 is composed of a proximal shaft 141 and a distal shaft 142, which are separate components, for example, the proximal shaft 141 may be made of resin and the distal shaft 142 may be made of metal. Furthermore, the shaft 140 may have a laminated structure made of different or the same materials.

[0064] The balloon 10 and the shaft 140 can be joined by adhesive bonding, welding, or by attaching a ring-shaped member to the overlapping portion of the balloon 10 and the shaft 140 and crimping it. In particular, it is preferable that the balloon 10 and the shaft 140 are joined by welding. By welding the balloon 10 and the shaft 140, the joint between the balloon 10 and the shaft 140 is less likely to come undone even if the balloon 10 is repeatedly expanded or contracted, thereby improving the joint strength.

[0065] Preferably, a tip member 170 is provided at the distal end of the balloon catheter 1. The tip member 170 may be provided at the distal end of the balloon catheter 1 by being connected to the distal end of the balloon 10 as a separate component from the inner shaft 160, or the inner shaft 160, which extends distal to the distal end of the balloon 10, may function as the tip member 170.

[0066] On the inner shaft 160 inside the balloon 10, radiopaque markers 180 may be placed at the location of the balloon 10 in the longitudinal axis direction x, so that the position of the balloon 10 can be confirmed under X-ray fluoroscopy. Preferably, the radiopaque markers 180 are placed at positions corresponding to both ends of the straight section of the balloon 10, or they may be placed at a position corresponding to the center of the straight section of the balloon 10 in the longitudinal axis direction x.

[0067] The number of radiopaque markers 180 is not particularly limited; there may be one or multiple. The shape of the radiopaque markers 180 is not particularly limited; for example, they may be cylindrical, polygonal, or other cylindrical shapes, have a C-shaped cross-section with a notch in the cylinder, or be a coil shape formed by winding a wire. Among these, the shape of the radiopaque markers 180 is preferably cylindrical.

[0068] Examples of materials that make up the X-ray opaque marker 180 include X-ray opaque materials such as lead, barium, iodine, tungsten, gold, platinum, iridium, stainless steel, titanium, and cobalt-chromium alloys.

[0069] A hub 5 may be provided on the proximal side of the shaft 140, and it is preferable that the hub 5 is provided with a fluid injection section 6 that communicates with the fluid flow path supplied to the inside of the balloon 10.

[0070] The shaft 140 and the hub 5 can be joined by, for example, adhesive bonding or welding. In particular, it is preferable that the shaft 140 and the hub 5 are joined by adhesive bonding. By bonding the shaft 140 and the hub 5, the bonding strength between the shaft 140 and the hub 5 can be increased, thereby improving the durability of the balloon catheter 1, especially when the materials constituting the shaft 140 and the hub 5 are different, for example, when the shaft 140 is made of a highly flexible material and the hub 5 is made of a highly rigid material.

[0071] Although not shown in the figures, this disclosure is also applicable to so-called over-the-wire balloon catheters, which have a guidewire insertion passage extending from the distal to the proximal end of the shaft. In the case of an over-the-wire balloon catheter, it is preferable that the inflation lumen and guidewire lumen extend to a hub located on the proximal end, and that the proximal opening of each lumen is provided in a bifurcated hub.

[0072] In the case of a rapid exchange type catheter, it is preferable that at least one of the outer walls of the proximal shaft 141 and the distal shaft 142 is appropriately coated, and it is more preferable that both the proximal shaft 141 and the distal shaft 142 are coated. In the case of an over-the-wire type catheter, it is preferable that the outer wall of the outer shaft is appropriately coated.

[0073] The coating can be hydrophilic or hydrophobic depending on the purpose, and can be applied by immersing the shaft 140 in a hydrophilic or hydrophobic coating agent, applying a hydrophilic or hydrophobic coating agent to the outer wall of the shaft 140, or covering the outer wall of the shaft 140 with a hydrophilic or hydrophobic coating agent. The coating agent may contain chemicals or additives.

[0074] Examples of hydrophilic coating agents include hydrophilic polymers such as polyvinyl alcohol, polyethylene glycol, polyacrylamide, polyvinylpyrrolidone, and methyl vinyl ether maleic anhydride copolymer, or hydrophilic coating agents made from any combination thereof.

[0075] 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.

[0076] This application claims the benefit of priority based on Japanese Patent Application No. 2024-172684, filed on October 1, 2024. The entire specification of Japanese Patent Application No. 2024-172684, filed on October 1, 2024, is incorporated herein by reference.

[0077] 1: Balloon catheter 5: Hub 6: Fluid injection section 10: Balloon 11: Feather-shaped section 21: Proximal sleeve section 22: Proximal tapered section 23: Straight section 24: Distal tapered section 25: Distal sleeve section 30: Convex section 31: One end 32: Other end 33: Curved section 34: First straight section 35: Second straight section 40: Concave section 50: First convex section 51: One end of the first convex section 52: Other end of the first convex section 53: Curved section of the first convex section 54: First straight section of the first convex section 55: Second straight section of the first convex section 60: Second convex section 61: One end of the second convex section 62: Other end of the second convex section 63: Curved section of the second convex section 64: First straight section of the second convex section 65: Second linear portion of the second convex part 140: Shaft 141: Proximal shaft 142: Distal shaft 150: Guide wire port 160: Inner shaft 170: Tip member 180: Radiopaque marker P1: Centroid of the cross-sectional shape of the straight tube part P2: Vertex of the convex part P3: Vertex of the first convex part P4: Vertex of the second convex part L1: Line connecting the centroid and vertex of the cross-sectional shape of the straight tube part D1: Distance from the centroid of the cross-sectional shape of the straight tube part D2: Length between the vertex and one end on the outer edge of the straight tube part D3: Length between the vertex and the other end on the outer edge of the straight tube part D4: Length of the first linear portion D5: Length of the second linear portion θ1: Angle between the second linear portion of the first convex part and the first linear portion of the second convex part

Claims

1. A balloon for a balloon catheter having 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, wherein the balloon 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, wherein in a cross section perpendicular to the longitudinal axis direction, the cross-sectional shape of the straight tube portion has at least one convex portion projecting outward from the balloon and at least one concave portion recessed inward from the balloon, wherein in a cross section perpendicular to the longitudinal axis direction, the convex portion has a vertex which is the point at which the distance from the centroid of the cross-sectional shape of the straight tube portion is greatest, and wherein in a cross section perpendicular to the longitudinal axis direction, the concave portion does not lie on a straight line connecting the centroid of the cross-sectional shape of the straight tube portion and the vertex.

2. In a cross section perpendicular to the longitudinal axis, the outer edge of the convex portion has one end in the circumferential direction and the other end opposite to the one end in the circumferential direction, and in a cross section perpendicular to the longitudinal axis, the length from the vertex on the outer edge of the straight tube portion to the one end is shorter than the length from the vertex on the outer edge of the straight tube portion to the other end. The balloon for a balloon catheter according to claim 1.

3. The balloon for a balloon catheter according to claim 2, wherein in a cross section perpendicular to the longitudinal axis direction in the straight tube portion, the outer edge of the convex portion has a curved portion including the vertex, a first straight portion including one end, and a second straight portion including the other end.

4. The balloon for a balloon catheter according to claim 3, wherein, in a cross section perpendicular to the longitudinal axis direction in the straight tube portion, the length of the first straight portion is shorter than the length of the second straight portion.

5. The number of protrusions is multiple, and the multiple protrusions include a first protrusion and a second protrusion adjacent to the first protrusion in the circumferential direction, and in a cross section perpendicular to the longitudinal axis direction in the straight pipe section, the outer edge of the first protrusion has one end of the first protrusion in the circumferential direction, the other end of the first protrusion opposite to the one end of the first protrusion in the circumferential direction, a curved portion including the vertex of the first protrusion, a first straight portion including the one end of the first protrusion, and a second straight portion including the other end of the first protrusion, and in a cross section perpendicular to the longitudinal axis direction in the straight pipe section, the outer edge of the second protrusion has one end of the second protrusion in the circumferential direction, the other end of the second protrusion opposite to the one end of the second protrusion in the circumferential direction, a curved portion including the vertex of the second protrusion, a first straight portion including the one end of the second protrusion, and a second straight portion including the other end of the second protrusion, The balloon for a balloon catheter according to claim 2, wherein the angle between the second linear portion of the first protrusion and the first linear portion of the second protrusion is less than 180 degrees.

6. The balloon for a 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, and the cross-sectional shapes of the proximal sleeve portion and the distal sleeve portion perpendicular to the longitudinal axis are circular.

7. A balloon catheter comprising a balloon for a balloon catheter as described in any one of claims 1 to 6.

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