Balloon for balloon catheter and balloon catheter

Abstract

A balloon (10) for a balloon catheter (1) satisfies at least one of conditions 1 and 2 in a state where a first pressure of 0.5 atm + 1 atm to 1.0 atm + 1 atm is applied to the inside of the balloon (10). Condition 1: An angle θ1 formed by a straight line L1 at the distal end of a proximal tapered part and a straight line L2 at the proximal end of the proximal tapered part is greater than 0 degrees. Condition 2: An angle θ2 formed by a straight line at the proximal end of a distal tapered part and a straight line at the distal end of the distal tapered part is greater than 0 degrees.

Description

Balloon for balloon catheter and balloon catheter

[0001] The present disclosure relates to a balloon for a balloon catheter and a balloon catheter including the balloon.

[0002] The formation of narrowed areas due to calcification and other factors in the inner walls of blood vessels can lead to diseases such as angina pectoris and myocardial infarction. One treatment for these conditions is angioplasty, which uses a balloon catheter to dilate the narrowed area. Angioplasty is a minimally invasive treatment that does not require open chest surgery like bypass surgery, and is widely used.

[0003] A balloon catheter is inserted into a body cavity with its 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 side to the distal side where the balloon is located. In angioplasty, the balloon delivered to the stenotic site (the treatment site) is inflated to dilate the stenotic site, and then the inflated balloon is deflated and the balloon catheter is removed from the body cavity. If the dilation of the stenotic site is insufficient, the balloon catheter is reinserted, the balloon is delivered to the treatment site, and the balloon is inflated to dilate the stenotic site.

[0004] For example, Patent Document 1 discloses a method for manufacturing a balloon catheter, which comprises preparing a mold having a mold cavity preformed to match the predetermined expanded shape of the balloon member, heating a tubular blank in the mold cavity, and inflating the tubular blank by creating a pressure difference between the inside and outside of the tubular blank, so that both ends of the tubular blank are twisted within a certain angle when the tubular blank is received in the mold. Patent Document 2 discloses a medical balloon having a proximal cone portion, a distal cone portion, and a body portion therebetween, the wall of at least one of the distal cone portion and the proximal cone portion defining at least one recessed portion, the recessed portion being at least one circumferential groove extending along the wall in a generally spiral-like pattern having a plurality of loops. Patent Document 3 discloses a medical balloon catheter in which spiral grooves and / or protrusions are formed in the balloon relative to the long axis of the balloon, and the grooves and / or protrusions formed in the tapered portion of the balloon extend continuously over an angle range of 15 degrees to 180 degrees from the start point to the axis center when viewed from the distal end of the balloon. Patent Document 4 discloses a method for manufacturing a medical device, including the steps of providing a medical balloon having a first conical portion and a main body portion, and removing material from the outer surface of the main body portion of the balloon to form a first region and a second region such that the first region is concave relative to the second region, wherein the step of removing material from the balloon comprises performing laser ablation on the balloon. Patent Document 5 discloses a catheter balloon having a cylindrical portion and tapered portions formed on both ends of the cylindrical portion, in which a plurality of high-rigidity portions having high rigidity are formed on one or both ends of the tapered portion radially from the tapered end or near the tapered end toward the cylindrical portion, and the high-rigidity portions are formed radially from the tapered end toward the cylindrical portion and curved in the circumferential direction.

[0005] Japanese Patent Application Laid-Open No. 08-299445 International Publication No. 2004 / 098696 International Publication No. 2004 / 101057 International Publication No. 2006 / 089115 Japanese Patent Application Laid-Open No. 2022-054780

[0006] When the conventional balloon is inflated and then deflated, the balloon membrane folds, forming wing-shaped portions. These wing-shaped portions are largely expanded in the radial direction. Therefore, even when the wing-shaped portions come into contact with the wall of a biological lumen, such as a stricture, they are less likely to collapse circumferentially, and they offer significant resistance to the wall of the biological lumen upon contact. Specifically, when a deflated balloon is passed through a biological lumen, the distal and proximal ends of the wing-shaped portions are more likely to come into frontal contact with the wall of the biological lumen. These ends offer strong resistance to forces in the longitudinal direction, making them less likely to bend or collapse until they buckle. High resistance from the wing-shaped portions when they come into contact with the wall of the biological lumen could damage the wall of the biological lumen or reduce the balloon's ability to pass through the biological lumen, hindering rapid procedures. Therefore, there is room for improvement.

[0007] In view of the above circumstances, the problem to be solved by the present disclosure is to provide a balloon for a balloon catheter, and a balloon catheter equipped with such a balloon, in which the wing-shaped portions formed when the balloon is deflated tend to collapse circumferentially around the balloon when they come into contact with the wall of the biological lumen, thereby reducing the risk of damaging the wall of the biological lumen and improving insertability through the biological lumen.

[0008] The balloon for a balloon catheter and the balloon catheter including the balloon according to embodiments of the present disclosure that have solved the above problems are as follows: [1] A balloon for a balloon catheter having a longitudinal axis direction extending from a proximal side to a distal side, a radial direction perpendicular to the longitudinal axis direction, and a circumferential direction, the balloon having a straight tube section, a proximal tapered section located proximal to the straight tube section, and a distal tapered section located distal to the straight tube section, wherein, when a first pressure of 0.5 atm + 1 atm (atmospheric pressure) or more and 1.0 atm + 1 atm (atmospheric pressure) or less is applied to the balloon, the cross-sectional shape of the proximal tapered section and the cross-sectional shape of the distal tapered section perpendicular to the longitudinal axis direction each have a convex portion protruding outward from the balloon, and the balloon for a balloon catheter satisfies at least one of the following [Condition 1] and [Condition 2] when the first pressure is applied to the balloon: [Condition 1] The angle θ1 formed by a line passing through the centroid of the cross-sectional shape of the balloon perpendicular to the longitudinal axis direction at the distal end of the proximal tapered section and the apex of the convex portion and a line passing through the centroid of the cross-sectional shape of the balloon perpendicular to the longitudinal axis direction at the proximal end of the proximal tapered section and the apex of the convex portion is greater than 0 degrees. [Condition 2] The angle θ2 formed by a line passing through the centroid of the cross-sectional shape of the balloon perpendicular to the longitudinal axis direction at the proximal end of the distal tapered section and the apex of the convex portion and a line passing through the centroid of the cross-sectional shape of the balloon perpendicular to the longitudinal axis direction at the distal end of the distal tapered section and the apex of the convex portion is greater than 0 degrees. [2] The balloon for a balloon catheter according to [1], which satisfies at least one of the following [Condition 3] and [Condition 4] when the first pressure is applied to the balloon. [Condition 3] When observed from a direction from the apex of the convex portion toward the longitudinal axis direction, a straight line passing through the apex of the convex portion at the distal end of the proximal taper portion and the apex of the convex portion at the proximal end of the proximal taper portion intersects with the longitudinal axis direction.[Condition 4] When observed from the direction from the apex of the convex portion toward the longitudinal axis direction, a straight line passing through the apex of the convex portion at the proximal end of the distal tapered portion and the apex of the convex portion at the distal end of the distal tapered portion intersects the longitudinal axis direction. [3] When the first pressure is applied to the inside of the balloon, when observed from the direction from the apex of the convex portion toward the longitudinal axis direction, at least one of the following angles θ3 formed by the apex of the convex portion at the distal end of the proximal tapered portion and the apex of the convex portion at the proximal end of the proximal tapered portion and the longitudinal axis direction is greater than 0 degrees and less than 90 degrees: [4] The balloon for a balloon catheter according to any one of [1] to [3], wherein, when the first pressure is applied to the balloon, the cross-sectional shape of the straight tube section perpendicular to the longitudinal axis direction has the convex portion, and when the first pressure is applied to the balloon, the angle θ5 formed by a line passing through the centroid of the cross-sectional shape of the balloon perpendicular to the longitudinal axis direction at the distal end of the straight tube section and the apex of the convex portion and a line passing through the centroid of the cross-sectional shape of the balloon perpendicular to the longitudinal axis direction at the proximal end of the straight tube section and the apex of the convex portion is smaller than at least one of the angle θ1 and the angle θ2. [5] The balloon for a balloon catheter according to any one of [1] to [4], wherein, when the first pressure is applied to the inside of the balloon, the cross-sectional shapes of the straight tube section, the proximal tapered section, and the distal tapered section perpendicular to the longitudinal axis direction are polygonal; and when a second pressure of 2.0 atm + 1 atm (atmospheric pressure) is applied to the inside of the balloon, the cross-sectional shapes of the straight tube section, the proximal tapered section, and the distal tapered section perpendicular to the longitudinal axis direction are circular.[6] The balloon for a balloon catheter according to any one of [1] to [5], wherein the balloon has a proximal sleeve portion located proximally relative 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 direction are circular. [7] A balloon catheter comprising the balloon for a balloon catheter according to any one of [1] to [6].

[0009] With the balloon for balloon catheter described above, when a first pressure is applied to the balloon, the angle θ1 formed by the line passing through the centroid of the cross-sectional shape of the balloon at the distal end of the proximal tapered section and the apex of the convex portion and the line passing through the centroid of the cross-sectional shape of the balloon at the proximal end of the proximal tapered section and the apex of the convex portion is greater than 0 degrees [Condition 1]; or the angle θ2 formed by the line passing through the centroid of the cross-sectional shape of the balloon at the proximal end of the distal tapered section and the apex of the convex portion and the line passing through the centroid of the cross-sectional shape of the balloon at the distal end of the distal tapered section and the apex of the convex portion is greater than 0 degrees [Condition 2]. By satisfying this condition, when the balloon is deflated, at least one of the proximal and distal tapered sections of the balloon will twist, causing the wing-shaped sections to fold so that the sides of the wing-shaped sections face proximally or distally. As a result, the sides of the wing-shaped portion are more likely to come into contact with the wall of the biological lumen, such as a narrowed area, making it easier for the wing-shaped portion to collapse and be folded so that it is wrapped around the circumferential direction of the balloon.

[0010] 1 shows a side view of a balloon according to an embodiment of the present disclosure in a state where a first pressure is applied.

[0023] FIG. 1 shows a cross-sectional view taken along II-II of the balloon shown in FIG. 1.

[0024] FIG. 1 shows a cross-sectional view taken along III-III of the balloon shown in FIG. 1.

[0025] FIG. 1 shows a cross-sectional view taken along IV-IV of the balloon shown in FIG. 1.

[0026] FIG. 1 shows a cross-sectional view taken along V-V of the balloon shown in FIG. 1.

[0027] FIG. 1 shows a view of the balloon shown in FIG. 1 observed from the apex of the convex portion at the proximal tapered section in the longitudinal axis direction.

[0028] FIG. 1 shows a view of the balloon shown in FIG. 1 observed from the apex of the convex portion at the distal tapered section in the longitudinal axis direction.

[0029] FIG. 1 shows a cross-sectional view showing a modification of the cross-sectional view shown in FIG. 2.

[0029] FIG. 3 shows a cross-sectional view showing a modification of the cross-sectional view shown in FIG. 4.

[0029] FIG. 5 shows a cross-sectional view of the balloon shown in FIG. 2 in a state where a second pressure is applied.

[0029] FIG. 4 shows a cross-sectional view of the balloon shown in FIG. 4 in a state where a second pressure is applied.

[0029] FIG. 5 shows a cross-sectional view of the balloon shown in FIG. 2 in a state where a second pressure is applied.

[0029] FIG. 6 shows a cross-sectional view of the balloon shown in FIG. 6 in a state where a second pressure is applied. 5 shows a cross-sectional view of the balloon shown in Figure 5 when a second pressure is applied. 17 shows a cross-sectional view of the balloon shown in Figure 1 taken along line XVII-XVII. 18 shows a cross-sectional view of the balloon shown in Figure 1 taken along line XVIII-XVIII. 19 shows a side view of a balloon catheter having the balloon shown in Figure 1.

[0011] The contents of the present disclosure will be described below based on the embodiments, but the contents of the present disclosure are not limited to the following embodiments, and can of course be implemented with appropriate modifications within the scope of the above and below-described intent, all of which are included within the technical scope of the present disclosure. Note that hatching and component symbols may be omitted in each drawing for convenience; in such cases, reference should be made to the specification or other drawings. Furthermore, the dimensions of various components in the drawings may differ from their actual dimensions, as priority is given to helping understand the features of the present disclosure.

[0012] A balloon for a balloon catheter according to an embodiment of the present disclosure is a balloon for a balloon catheter having a longitudinal axis direction extending from the proximal side to the distal side, a radial direction perpendicular to the longitudinal axis direction, and a circumferential direction, the balloon having a straight tube section, a proximal tapered section located proximal to the straight tube section, and a distal tapered section located distal to the straight tube section, and when a first pressure of 0.5 atm + 1 atm (atmospheric pressure) or more and 1.0 atm + 1 atm (atmospheric pressure) or less is applied to the balloon, the cross-sectional shapes of the proximal tapered section and the distal tapered section perpendicular to the longitudinal axis direction each have convex portions that protrude outward from the balloon, and when the first pressure is applied to the balloon, at least one of [Condition 1] and [Condition 2] below is satisfied. [Condition 1] The angle θ1 formed by a line passing through the centroid of the cross-sectional shape of the balloon perpendicular to the longitudinal axis direction at the distal end of the proximal tapered portion and the apex of the convex portion and a line passing through the centroid of the cross-sectional shape of the balloon perpendicular to the longitudinal axis direction at the proximal end of the proximal tapered portion and the apex of the convex portion is greater than 0 degrees. [Condition 2] The angle θ2 formed by a line passing through the centroid of the cross-sectional shape of the balloon perpendicular to the longitudinal axis direction at the proximal end of the distal tapered portion and the apex of the convex portion and a line passing through the centroid of the cross-sectional shape of the balloon perpendicular to the longitudinal axis direction at the distal end of the distal tapered portion and the apex of the convex portion is greater than 0 degrees.

[0013] In this specification, the cross-sectional shape of the balloon perpendicular to the longitudinal axis direction refers to the outer edge shape of the balloon 10 in that cross section, i.e., the shape of the outline. The same meaning will be used hereinafter. In this specification, the centroid refers to the center of gravity of the area surrounded by the outline (outline) of the balloon in the cross section of the balloon perpendicular to the longitudinal axis direction of the catheter.

[0014] Hereinafter, a balloon for a balloon catheter according to an embodiment of the present disclosure will be described with reference to Figures 1 to 19. Figure 1 is a side view of a balloon with a first pressure applied. Figure 2 is a cross-sectional view taken along II-II of the balloon shown in Figure 1, showing a cross-section perpendicular to the longitudinal axis direction at the distal end of the proximal tapered section and the proximal end of the straight section of the balloon. Figure 3 is a cross-sectional view taken along III-III of the balloon shown in Figure 1, showing a cross-section perpendicular to the longitudinal axis direction at the proximal end of the proximal tapered section of the balloon. Figure 4 is a cross-sectional view taken along IV-IV of the balloon shown in Figure 1, showing a cross-section perpendicular to the longitudinal axis direction at the proximal end of the distal tapered section and the distal end of the straight section of the balloon. Figure 5 is a cross-sectional view taken along V-V of the balloon shown in Figure 1, showing a cross-section perpendicular to the longitudinal axis direction at the distal end of the distal tapered section of the balloon. Figure 6 shows a view of the balloon shown in Figure 1 observed from the apex of the convex portion in the proximal tapered portion toward the longitudinal axis direction, Figure 7 shows a view of the balloon shown in Figure 1 observed from the apex of the convex portion in the distal tapered portion toward the longitudinal axis direction, and Figure 8 shows a view of the balloon shown in Figure 1 observed from the apex of the convex portion in the straight tube portion toward the longitudinal axis direction.

[0015] Figure 9 is a cross-sectional view showing a modified example of the cross-sectional view of the balloon shown in Figure 2, Figure 10 is a cross-sectional view showing a modified example of the cross-sectional view of the balloon shown in Figure 3, Figure 11 is a cross-sectional view showing a modified example of the cross-sectional view of the balloon shown in Figure 4, and Figure 12 is a cross-sectional view showing a modified example of the cross-sectional view of the balloon shown in Figure 5.

[0016] Figure 13 is a cross-sectional view of the balloon shown in Figure 2 when a second pressure is applied, taken along a line perpendicular to the longitudinal axis at the distal end of the proximal tapered portion of the balloon. Figure 14 is a cross-sectional view of the balloon shown in Figure 3 when a second pressure is applied, taken along a line perpendicular to the longitudinal axis at the proximal end of the proximal tapered portion of the balloon. Figure 15 is a cross-sectional view of the balloon shown in Figure 4 when a second pressure is applied, taken along a line perpendicular to the longitudinal axis at the proximal end of the distal tapered portion of the balloon. Figure 16 is a cross-sectional view of the balloon shown in Figure 5 when a second pressure is applied, taken along a line perpendicular to the longitudinal axis at the distal end of the distal tapered portion of the balloon.

[0017] Fig. 17 is a cross-sectional view taken along line XVII-XVII of the balloon shown in Fig. 1, which shows a cross-sectional view perpendicular to the longitudinal axis direction at the proximal sleeve portion of the balloon, Fig. 18 is a cross-sectional view taken along line XVIII-XVIII of the balloon shown in Fig. 1, which shows a cross-sectional view perpendicular to the longitudinal axis direction at the distal sleeve portion of the balloon, Fig. 19 is a side view of a balloon catheter having the balloon shown in Fig. 1.

[0018] 1 and 19, the balloon 10 is a balloon 10 for a balloon catheter 1, which has a longitudinal axis direction x extending from the proximal side to the distal side, a radial direction y perpendicular to the longitudinal axis direction x, and a circumferential direction z. In this specification, a balloon for a balloon catheter may be simply referred to as a "balloon."

[0019] 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. In the radial direction y, "inward" refers to the direction toward the longitudinal axis of the balloon 10, and "outward" refers to the direction extending radially from the longitudinal axis 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 periphery 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 the proximal side, i.e., the direction toward the patient, is referred to as the distal side. Furthermore, when each component 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 component or part is referred to as the distal portion of each component or part, and the part located on the proximal side of each component or part is referred to as the proximal portion of each component or part. The distal end of each member or part is the end located most distally of each member or part. The proximal end of each member or part is the end located most proximally of each member or part. The end includes the peripheral portion of the end. That is, the distal end refers to the distal end and the peripheral portion of the distal end, and the proximal end refers to the proximal end and the peripheral portion of the proximal end.

[0020] Components and parts other than the balloon 10 also have longitudinal axis directions, radial directions, and circumferential directions, which may or may not be the same as the longitudinal axis directions x, radial directions y, and circumferential directions z of the balloon 10. However, for ease of understanding, this specification will be described as assuming that all components and parts have the same longitudinal axis directions x, radial directions y, and circumferential directions z as the longitudinal axis directions x, radial directions y, and circumferential directions z of the balloon 10.

[0021] The balloon 10 is located at the distal portion of the balloon catheter 1. The balloon 10 can be expanded by introducing fluid into the lumen of the balloon 10, and can be deflated by expelling fluid from the lumen of the balloon 10.

[0022] The balloon catheter 1 dilates the stenotic site by inserting the balloon 10 provided at the distal end of the balloon catheter 1 into the lumen of the blood vessel, delivering it to the stenotic site, and then inflating the balloon 10. When inserting the balloon 10 into the stenotic site or when removing the balloon 10 from the body, fluid is discharged from the lumen of the balloon 10 to deflate it, and the wing-shaped portion formed by the balloon membrane of the deflated balloon 10 can be wrapped around the shaft 140 of the balloon catheter 1, thereby reducing the outer diameter of the balloon 10.

[0023] As shown in FIG. 1 , the balloon 10 has a straight tube portion 23, a proximal tapered portion 22 located proximal to the straight tube portion 23, and a distal tapered portion 24 located distal to the straight tube portion 23.

[0024] The straight tube portion 23 is preferably substantially cylindrical, with approximately the same diameter at any position along the longitudinal axis x, when the balloon 10 is inflated. However, the diameter may vary depending on the position along the longitudinal axis x. The proximal tapered portion 22 and the distal tapered portion 24 are preferably formed into a substantially conical or truncated conical shape, with their diameters decreasing with increasing distance from the straight tube portion 23, when the balloon 10 is inflated. Having the straight tube portion 23 have the largest diameter when the balloon 10 is inflated, allows the straight tube portion 23 to sufficiently contact the lesion when the balloon 10 is inflated at a lesion such as a stenosis, facilitating treatment such as dilation of the lesion. Furthermore, having the proximal tapered portion 22 and the distal tapered portion 24 reduced in diameter when the balloon 10 is inflated makes it easier to reduce the outer diameters of the proximal and distal ends of the balloon 10 when the balloon 10 is deflated. Furthermore, the step between the shaft 140 of the balloon catheter 1 and the balloon 10 can be reduced, facilitating insertion of the balloon 10 into a body cavity.

[0025] 1 , the balloon 10 preferably 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. The proximal tapered portion 22, the straight tube portion 23, and the distal tapered portion 24 are portions that expand when a fluid is introduced into the balloon 10, whereas the proximal sleeve portion 21 and the distal sleeve portion 25 are preferably portions that do not expand. Because the proximal sleeve portion 21 and the distal sleeve portion 25 are portions that do not expand, it becomes easier to firmly fix at least a portion of the proximal sleeve portion 21 and at least a portion of the distal sleeve portion 25 to a member such as the shaft 140.

[0026] Examples of materials that can be used to form the balloon 10 include polyamide resins such as nylon 11 and nylon 12, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polyurethane resins, and thermoplastic elastomers such as polyether block amide copolymers.

[0027] The balloon 10 can be obtained by biaxially stretching or blow molding a parison. The parison is a cylindrical member made of resin and has an internal cavity. Like the balloon 10, the parison has a longitudinal axis direction x, a radial direction y, and a circumferential direction z. The parison can be obtained, for example, by extrusion molding a resin using a cylindrical mold.

[0028] 2 to 5 , when a first pressure of 0.5 atm+1 atm (atmospheric pressure) or more and 1.0 atm+1 atm (atmospheric pressure) or less is applied to the interior of the balloon 10, the cross-sectional shapes of the proximal tapered section 22 and the distal tapered section 24 perpendicular to the longitudinal axis direction x each have a convex portion 30 that protrudes outward from the balloon 10. In other words, when a pressure of 0.5 atm or more and 1.0 atm (based on atmospheric pressure (1 atm)) is applied to the lumen of the balloon 10, the cross-sectional shape perpendicular to the longitudinal axis direction x of the proximal tapered section 22 has a convex portion 30 that protrudes outward from the balloon 10, and the cross-sectional shape perpendicular to the longitudinal axis direction x of the distal tapered section 24 has a convex portion 30 that protrudes outward from the balloon 10.

[0029] One method of applying the first pressure to the balloon 10 is to inject a fluid into the lumen of the balloon 10. The fluid injected into the balloon 10 may be a liquid such as water or saline, or a gas such as air or oxygen gas. Among these, air is preferably the fluid injected into the balloon 10. By using air as the fluid injected into the balloon 10, the fluid is less susceptible to the influence of surface tension, making it easier to confirm the cross-sectional shape of the balloon 10 when the first pressure is applied to the balloon 10. The fluid may be pressurized using, for example, a syringe, an indeflator, a pump, or the like and injected into the lumen of the balloon 10.

[0030] The cross-sectional shape of the proximal tapered section 22 and the cross-sectional shape of the distal tapered section 24 each have at least one convex portion 30. Because the cross-sectional shape of the proximal tapered section 22 and the cross-sectional shape of the distal tapered section 24 each have a convex portion 30, the convex portion 30 is more likely to form a wing-shaped portion when the balloon 10 is deflated. This makes it easier to control the location where the wing-shaped portion is formed when the balloon 10 is deflated.

[0031] In a cross section perpendicular to the longitudinal axis direction x, the cross-sectional shape of the proximal tapered portion 22 and the cross-sectional shape of the distal tapered portion 24 preferably each have a plurality of convex portions 30. By having a plurality of convex portions 30 in the cross-sectional shapes of the proximal tapered portion 22 and the distal tapered portion 24, multiple wing-shaped portions are more likely to be formed when the balloon 10 is deflated, making it easier to fold the balloon 10 so that the outer diameter thereof becomes smaller.

[0032] In a cross section perpendicular to the longitudinal axis direction x, the number of convex portions 30 in each of the cross-sectional shapes of the proximal taper portion 22 and the distal taper portion 24 is preferably two or more, and more preferably three or more. By setting the lower limit of the number of convex portions 30 in each of the cross-sectional shapes of the proximal taper portion 22 and the distal taper portion 24 within the above range, the outer diameter of the balloon 10 is likely to be reduced when the balloon 10 is deflated to fold the wing-shaped portions. Furthermore, the number of convex portions 30 in each of the cross-sectional shapes of the proximal taper portion 22 and the distal taper portion 24 is preferably ten or less, more preferably eight or less, even more preferably six or less, and even more preferably four or less. By setting the upper limit of the number of convex portions 30 in each of the cross-sectional shapes of the proximal taper portion 22 and the distal taper portion 24 within the above range, the number of wing-shaped portions formed by deflation of the balloon 10 is not too large, making it easier to fold the wing-shaped portions along the circumferential direction z. In particular, it is most preferable that the number of convex portions 30 in the cross section perpendicular to the longitudinal axis direction x of each of the proximal tapered portion 22 and the distal tapered portion 24 is three.

[0033] When the cross-sectional shape of the proximal tapered portion 22 has a plurality of protrusions 30 in a cross section perpendicular to the longitudinal axis direction x, the sizes and shapes of the plurality of protrusions 30 in the longitudinal axis direction x, the radial direction y, and the circumferential direction z may be the same or different. Furthermore, when the cross-sectional shape of the distal tapered portion 24 has a plurality of protrusions 30 in a cross section perpendicular to the longitudinal axis direction x, the sizes and shapes of the plurality of protrusions 30 in the longitudinal axis direction x, the radial direction y, and the circumferential direction z may be the same or different.

[0034] When a first pressure is applied to the balloon 10, the cross-sectional shapes of the proximal tapered portion 22 and the distal tapered portion 24 perpendicular to the longitudinal axis direction x may have a recess 40 recessed toward the inside of the balloon 10, as shown in Figures 2 to 5, or may not have a recess 40, as shown in Figures 9 to 12. As shown in Figures 2 to 5, the recess 40 is preferably located between adjacent protrusions 30 in the circumferential direction z. In other words, the recess 40 is preferably located at the boundary between two adjacent protrusions 30 in the circumferential direction z.

[0035] When a first pressure is applied to the balloon 10, the cross-sectional shapes of the proximal tapered portion 22 and the distal tapered portion 24 each have a recess 40, which makes it easier for the recess 40 to become the end of the wing-shaped portion in the circumferential direction z when the balloon 10 is deflated, making it easier to control the position where the wing-shaped portion is formed. Furthermore, when a first pressure is applied to the balloon 10, the cross-sectional shapes of the proximal tapered portion 22 and the distal tapered portion 24 do not have a recess 40, which makes it easier for the balloon 10 to expand significantly in the circumferential direction z, making it easier to increase the expansion force of the balloon 10.

[0036] In a cross section perpendicular to the longitudinal axis direction x, the cross-sectional shapes of the proximal tapered portion 22 and the distal tapered portion 24 may have a plurality of recesses 40. When the cross-sectional shapes of the proximal tapered portion 22 and the distal tapered portion 24 have a plurality of recesses 40, the sizes and shapes of the plurality of recesses 40 in the longitudinal axis direction x, radial direction y, and circumferential direction z may be the same or different.

[0037] When a first pressure is applied to the inside of the balloon 10, the balloon 10 satisfies at least one of the following [Condition 1] and [Condition 2].

[0038] [Condition 1] As shown in Figures 2 and 3, the angle θ1 formed by a line L1 passing through the centroid P1 of the cross-sectional shape of the balloon 10 perpendicular to the longitudinal axis direction x at the distal end 22d of the proximal tapered portion 22 and the apex P2 of the convex portion 30 and a line L2 passing through the centroid P3 of the cross-sectional shape of the balloon 10 perpendicular to the longitudinal axis direction x at the proximal end 22p of the proximal tapered portion 22 and the apex P4 of the convex portion 30 is greater than 0 degrees.

[0039] Apex P2 is located on the outer edge of convex portion 30 in a cross section perpendicular to the longitudinal axis direction x at distal end 22d of proximal taper portion 22 when a first pressure is applied to the balloon 10, and refers to the point on the outer edge of convex portion 30 that is the furthest from centroid P1 of the cross-sectional shape at distal end 22d of proximal taper portion 22. Apex P4 is located on the outer edge of convex portion 30 in a cross section perpendicular to the longitudinal axis direction x at proximal end 22p of proximal taper portion 22 when a first pressure is applied to the balloon 10, and refers to the point on the outer edge of convex portion 30 that is the furthest from centroid P3 of the cross-sectional shape at proximal end 22p of proximal taper portion 22.

[0040] When the cross-sectional shape of the proximal tapered portion 22 perpendicular to the longitudinal axis direction x has a plurality of convex portions 30, the apex of one convex portion 30 at the distal end 22d of the proximal tapered portion 22 is apex P2, and the apex of the one convex portion 30 at the proximal end 22p of the proximal tapered portion 22 is apex P4. In other words, the apex P2 and the apex P4 are apexes that exist in the same convex portion 30 of the proximal tapered portion 22.

[0041] In Fig. 2, a line L2 passing through a centroid P3 of the cross-sectional shape of the balloon 10 perpendicular to the longitudinal axis direction x at the proximal end 22p of the proximal tapered section 22 and a vertex P4 of the convex portion 30 is shown by a dashed line, and an angle θ1 is indicated. In Fig. 3, a line L1 passing through a centroid P1 of the cross-sectional shape of the balloon 10 perpendicular to the longitudinal axis direction x at the distal end 22d of the proximal tapered section 22 and a vertex P2 of the convex portion 30 is shown by a dashed line, and an angle θ1 is indicated.

[0042] In addition, if the cross-sectional shape of the proximal tapered portion 22 perpendicular to the longitudinal axis direction x has multiple convex portions 30, the angle θ1 is measured at the convex portion 30 where the angle θ1 is largest by drawing a straight line L1 passing through the centroid P1 and vertex P2 of the cross-sectional shape of the balloon 10 at the distal end 22d of the proximal tapered portion 22, and a straight line L2 passing through the centroid P3 and vertex P4 of the cross-sectional shape of the balloon 10 at the proximal end 22p of the proximal tapered portion 22.

[0043] 2 and 3, when the first pressure is applied to the balloon 10, the balloon 10 satisfies Condition 1, so that the apexes of the proximal tapered section 22, including apexes P2 and P4 of the convex portions 30, become non-parallel to the longitudinal axis direction x, forming a twisted shape. As a result, when the balloon 10 is deflated, the sides of the wing-shaped portions formed in the proximal tapered section 22 face proximally.

[0044] [Condition 2] As shown in Figures 4 and 5, the angle θ2 formed by a line L3 passing through the centroid P5 of the cross-sectional shape of the balloon 10 perpendicular to the longitudinal axis direction x at the proximal end 24p of the distal tapered portion 24 and the apex P6 of the convex portion 30 and a line L4 passing through the centroid P7 of the cross-sectional shape of the balloon 10 perpendicular to the longitudinal axis direction x at the distal end 24d of the distal tapered portion 24 and the apex P8 of the convex portion 30 is greater than 0 degrees.

[0045] Vertex P6 is located on the outer edge of convex portion 30 in a cross section perpendicular to the longitudinal axis direction x at proximal end 24p of distal tapered portion 24 when a first pressure is applied to the balloon 10, and refers to the point on the outer edge of convex portion 30 that is the furthest from centroid P5 of the cross-sectional shape at proximal end 24p of distal tapered portion 24. Vertex P8 is located on the outer edge of convex portion 30 in a cross section perpendicular to the longitudinal axis direction x at distal end 24d of distal tapered portion 24 when a first pressure is applied to the balloon 10, and refers to the point on the outer edge of convex portion 30 that is the furthest from centroid P7 of the cross-sectional shape at distal end 24d of distal tapered portion 24.

[0046] When the cross-sectional shape of the distal tapered portion 24 perpendicular to the longitudinal axis direction x has a plurality of convex portions 30, the apex of one convex portion 30 at the proximal end 24p of the distal tapered portion 24 is apex P6, and the apex of the one convex portion 30 at the distal end 24d of the distal tapered portion 24 is apex P8. In other words, apex P6 and apex P8 are apexes that exist in the same convex portion 30 of the distal tapered portion 24.

[0047] In Fig. 4, a line L4 passing through a centroid P7 of the cross-sectional shape of the balloon 10 perpendicular to the longitudinal axis direction x at the distal end 24d of the distal tapered portion 24 and a vertex P8 of the convex portion 30 is shown by a dashed line, and an angle θ2 is indicated. In Fig. 3, a line L3 passing through a centroid P5 of the cross-sectional shape of the balloon 10 perpendicular to the longitudinal axis direction x at the proximal end 24p of the distal tapered portion 24 and a vertex P6 of the convex portion 30 is shown by a dashed line, and an angle θ2 is indicated.

[0048] In addition, if the cross-sectional shape of the distal tapered portion 24 perpendicular to the longitudinal axis direction x has multiple convex portions 30, the angle θ2 is measured at the convex portion 30 where the angle θ2 is largest by drawing a straight line L3 passing through the centroid P5 and vertex P6 of the cross-sectional shape of the balloon 10 at the proximal end 24p of the distal tapered portion 24, and a straight line L4 passing through the centroid P7 and vertex P8 of the cross-sectional shape of the balloon 10 at the distal end 24d of the distal tapered portion 24.

[0049] 4 and 5, when the first pressure is applied to the balloon 10, the balloon 10 satisfies Condition 2, so that the apexes of the convex portions 30, including apexes P6 and P8, in the distal tapered portion 24 are non-parallel to the longitudinal axis direction x, forming a twisted shape. As a result, when the balloon 10 is deflated, the sides of the wing-shaped portions formed in the distal tapered portion 24 face distally.

[0050] When a first pressure is applied to the balloon 10, the balloon 10 satisfies at least one of [Condition 1] and [Condition 2], so that at least one of the proximal tapered portion 22 and the distal tapered portion 24 of the balloon 10 assumes a twisted shape, such that the sides of the wing-shaped portions of the proximal tapered portion 22 face proximally or the sides of the distal tapered portion 24 face distally when the balloon 10 is deflated. Having the sides of the wing-shaped portions of the proximal tapered portion 22 facing proximally or the sides of the wing-shaped portions of the distal tapered portion 24 facing distally makes it easier for the sides of the wing-shaped portions to come into contact with the wall of a biological lumen, such as a stenosis.

[0051] When the balloon 10 is inserted through a biological lumen such as a stenosis, the wing-shaped portions are more susceptible to contact with the sides of the wing-shaped portions in the longitudinal direction x than to contact with the distal or proximal ends of the wing-shaped portions in the longitudinal direction x, and the contact force acts as a bending moment, making the wing-shaped portions more likely to collapse in the circumferential direction z. As a result, the wing-shaped portions are more likely to collapse when their sides come into contact with the wall of the biological lumen, and the wing-shaped portions are more likely to fold in a wrapped manner around the balloon 10 in the circumferential direction z, making the balloon 10 easier to pass through the biological lumen.

[0052] It is preferable that the balloon 10 satisfies Condition 1 and Condition 2 when the first pressure is applied to the inside of the balloon 10. When the balloon 10 satisfies both Condition 1 and Condition 2, both the proximal tapered portion 22 and the distal tapered portion 24 of the balloon 10 have a twisted shape, making the wing-shaped portions more likely to collapse and allowing the balloon 10 to be easily folded in a wound manner along the circumferential direction z.

[0053] In Condition 1, the angle θ1 is preferably 3 degrees or greater, more preferably 5 degrees or greater, and even more preferably 7 degrees or greater. Setting the lower limit of the angle θ1 in Condition 1 within the above range facilitates sufficient twisting of the cross-sectional shape of the balloon 10 at the proximal taper section 22, making it easier for the sides of the wing-shaped portions to face proximally when the balloon 10 is deflated, facilitating contact with the wall of the biological lumen. In Condition 1, the angle θ1 is preferably less than 90 degrees, more preferably 75 degrees or less, even more preferably 60 degrees or less, and even more preferably 45 degrees or less. Setting the upper limit of the angle θ1 in Condition 1 within the above range facilitates folding of the wing-shaped portions in a rolled manner along the circumferential direction z when the balloon 10 is deflated, thereby reducing the outer diameter of the balloon 10 in the deflated state.

[0054] In Condition 2, the angle θ2 is preferably 3 degrees or greater, more preferably 5 degrees or greater, and even more preferably 7 degrees or greater. Setting the lower limit of the angle θ2 in Condition 2 within the above range facilitates the formation of a sufficiently twisted cross-sectional shape of the balloon 10 at the distal tapered section 24, which in turn facilitates the sides of the wing-shaped portions facing distally when the balloon 10 is deflated, thereby facilitating contact between the sides of the wing-shaped portions and the wall of the biological lumen. Furthermore, in Condition 2, the angle θ2 is preferably less than 90 degrees, more preferably 75 degrees or less, even more preferably 60 degrees or less, and even more preferably 45 degrees or less. Setting the upper limit of the angle θ2 in Condition 2 within the above range facilitates the folding of the wing-shaped portions along the circumferential direction z when the balloon 10 is deflated, thereby facilitating the reduction of the outer diameter of the balloon 10 in the deflated state.

[0055] It is preferable that the balloon 10 satisfies at least one of the following [Condition 3] and [Condition 4] when the first pressure is applied to the inside of the balloon 10.

[0056] [Condition 3] As shown in Figure 6, when observed from the direction toward the longitudinal axis direction x from the vertices P2 and P4 of the convex portion 30, a straight line L5 passing through the vertex P2 of the convex portion 30 at the distal end 22d of the proximal taper portion 22 and the vertex P4 of the convex portion 30 at the proximal end 22p of the proximal taper portion 22 intersects with the longitudinal axis direction x.

[0057] [Condition 4] As shown in Figure 7, when observed from the direction toward the longitudinal axis direction x from the vertices P6 and P8 of the convex portion 30, a straight line L6 passing through the vertex P6 of the convex portion 30 at the proximal end 24p of the distal tapered portion 24 and the vertex P8 of the convex portion 30 at the distal end 24d of the distal tapered portion 24 intersects with the longitudinal axis direction x.

[0058] Condition 3 means that, in the proximal tapered portion 22, a straight line L5 passing through the apex P2 of the convex portion 30 at the distal end 22d of the proximal tapered portion 22 and the apex P4 of the convex portion 30 at the proximal end 22p of the proximal tapered portion 22 is non-parallel to the longitudinal axis direction x. The fact that the balloon 10 satisfies Condition 3 means that, in the proximal tapered portion 22, the extension direction of the convex portion 30 is twisted with respect to the longitudinal axis direction x.

[0059] Condition 4 means that, in the distal tapered portion 24, a straight line L6 passing through the apex P6 of the convex portion 30 at the proximal end 24p of the distal tapered portion 24 and the apex P8 of the convex portion 30 at the distal end 24d of the distal tapered portion 24 is non-parallel to the longitudinal axis direction x. The fact that the balloon 10 satisfies Condition 4 indicates that, in the distal tapered portion 24, the extension direction of the convex portion 30 is twisted with respect to the longitudinal axis direction x.

[0060] When the first pressure is applied to the balloon 10, the balloon 10 satisfies at least one of [Condition 3] and [Condition 4], so that the convex portions 30 are twisted with respect to the longitudinal axis direction x in at least one of the proximal tapered portion 22 and the distal tapered portion 24 of the balloon 10. Therefore, when the balloon 10 is deflated, the sides of the wing-shaped portions are more likely to come into contact with the wall of the biological lumen, and the wing-shaped portions are more likely to be folded in a wrapped manner.

[0061] It is more preferable that the balloon 10 satisfy Condition 3 and Condition 4 when the first pressure is applied to the balloon 10. When the balloon 10 satisfies both Condition 3 and Condition 4, the extension direction of the convex portions 30 in both the proximal tapered portion 22 and the distal tapered portion 24 of the balloon 10 is twisted in the longitudinal axis direction x. This makes it easier for the wing-shaped portions to come into contact with the wall of the biological lumen, making it easier for the wing-shaped portions to collapse and be folded up in a rolled manner.

[0062] As shown in Figures 6 and 7, when a first pressure is applied to the balloon 10, when observed from the direction toward the longitudinal axis direction x from the apexes P2 and P4 of the convex portions 30, it is preferable that at least one of the following angles θ3, which is formed between the longitudinal axis direction x and a line L5 passing through the apex P2 of the convex portions 30 at the distal end 22d of the proximal taper portion 22 and the apex P4 of the convex portions 30 at the proximal end 22p of the proximal taper portion 22, and the line L6 passing through the apex P6 of the convex portions 30 at the proximal end 24p of the distal taper portion 24 and the apex P8 of the convex portions 30 at the distal end 24d of the distal taper portion 24, is greater than 0 degrees and less than 90 degrees.

[0063] By setting at least one of the angles θ3 and θ4 to greater than 0 degrees and less than 90 degrees, it becomes easier to increase at least one of the areas of the sides of the wing-shaped portions formed in the proximal tapered section 22 facing proximally and the areas of the sides of the wing-shaped portions formed in the distal tapered section 24 facing distally when the balloon 10 is deflated. As a result, the sides of the wing-shaped portions of at least one of the proximal tapered section 22 and the distal tapered section 24 are more likely to come into contact with the wall of the biological lumen, making the wing-shaped portions more likely to collapse when deflated.

[0064] The angle θ3 between the line L5 and the longitudinal axis direction x is preferably 3 degrees or greater, more preferably 5 degrees or greater, and even more preferably 7 degrees or greater. Setting the lower limit of the angle θ3 within the above range facilitates increasing the area of ​​the proximal-facing side of the wing-shaped portion formed in the proximal taper section 22 when the balloon 10 is deflated, thereby facilitating contact with the wall of the biological lumen. Furthermore, the angle θ3 is preferably 75 degrees or less, more preferably 60 degrees or less, and even more preferably 45 degrees or less. Setting the upper limit of the angle θ3 within the above range facilitates folding of the wing-shaped portion of the proximal taper section 22 in a wrapped manner along the circumferential direction z when the balloon 10 is deflated, thereby reducing the outer diameter of the balloon 10 in the deflated state.

[0065] The angle θ4 between the line L6 and the longitudinal axis direction x is preferably 3 degrees or greater, more preferably 5 degrees or greater, and even more preferably 7 degrees or greater. Setting the lower limit of the angle θ4 within the above range increases the area of ​​the distally facing side of the wing-shaped portion formed in the distal taper section 24 during deflation of the balloon 10, thereby facilitating contact with the wall of the biological lumen. Furthermore, the angle θ4 is preferably 75 degrees or less, more preferably 60 degrees or less, and even more preferably 45 degrees or less. Setting the upper limit of the angle θ4 within the above range facilitates folding of the wing-shaped portion of the distal taper section 24 in a wrapped manner along the circumferential direction z during deflation of the balloon 10, thereby enabling the balloon 10 to have a small outer diameter in the deflated state.

[0066] It is more preferable that the angle θ3 between the line L5 and the longitudinal axis direction x and the angle θ4 between the line L6 and the longitudinal axis direction x are greater than 0 degrees and less than 90 degrees when the first pressure is applied to the balloon 10. When both the angle θ3 and the angle θ4 are greater than 0 degrees and less than 90 degrees, both the proximal tapered section 22 and the distal tapered section 24 can be formed as wing-shaped sections that are likely to come into contact with the wall of the biological lumen when the balloon 10 is deflated and that tend to collapse upon contact.

[0067] 6, when the first pressure is applied to the balloon 10, the apex P2 of the convex portion 30 at the distal end 22d of the proximal taper portion 22 is preferably circumferentially offset from the apex P4 of the convex portion 30 at the proximal end 22p of the proximal taper portion 22. This causes the extension direction of the convex portion 30 of the proximal taper portion 22 of the balloon 10 to be twisted in the longitudinal axis direction x.

[0068] As shown in Figure 6, when the balloon catheter 1 is viewed from the proximal side to the distal side with the first pressure applied to the balloon 10, the apex P2 of the convex portion 30 at the distal end 22d of the proximal tapered portion 22 is preferably offset clockwise in the circumferential direction from the apex P4 of the convex portion 30 at the proximal end 22p of the proximal tapered portion 22. More preferably, the apex P2 is offset clockwise in the circumferential direction from the apex P4 by a first predetermined angle. The first predetermined angle is not particularly limited, but may be set to, for example, a value between 1 degree and 45 degrees.

[0069] 7, when the first pressure is applied to the balloon 10, the apex P6 of the convex portion 30 at the proximal end 24p of the distal tapered portion 24 is preferably circumferentially offset from the apex P8 of the convex portion 30 at the distal end 24d of the distal tapered portion 24. This causes the extension direction of the convex portion 30 of the distal tapered portion 24 of the balloon 10 to be twisted in the longitudinal axis direction x.

[0070] As shown in Figure 7, when the balloon catheter 1 is viewed from the proximal side to the distal side with the first pressure applied to the balloon 10, the apex P6 of the convex portion 30 at the proximal end 24p of the distal tapered portion 24 is preferably offset counterclockwise in the circumferential direction from the apex P8 of the convex portion 30 at the distal end 24d of the distal tapered portion 24. More preferably, the apex P6 is offset counterclockwise in the circumferential direction from the apex P8 by a second predetermined angle. The second predetermined angle is not particularly limited, but may be set to, for example, between 1 degree and 45 degrees.

[0071] The first and second predetermined angles may be the same, or one may be larger than the other. Setting the first and second predetermined angles to the same value allows the wing-shaped portions to collapse almost evenly overall. On the other hand, as can be seen from FIGS. 7 and 8 , the first predetermined angle may be smaller than the second predetermined angle. By setting the first predetermined angle smaller than the second predetermined angle, the amount of twist of the convex portion 30 of the proximal tapered portion 22 can be made smaller than that of the distal tapered portion 24, allowing the wing-shaped portions to collapse earlier on the proximal side and to be folded with greater twist on the distal side. This allows the wing-shaped portions to collapse gradually when passing through a stricture, further reducing the resistance to passage of the balloon 10.

[0072] 2 and 4 , when a first pressure is applied to the inside of the balloon 10, the cross-sectional shape of the straight tube section 23 perpendicular to the longitudinal axis direction x preferably has a convex portion 30. In other words, when a pressure of 0.5 atm or more and 1.0 atm or less, based on atmospheric pressure (1 atm), is applied to the inner cavity of the balloon 10, the cross-sectional shape of the straight tube section 23 perpendicular to the longitudinal axis direction x preferably has a convex portion 30 that protrudes outward from the balloon 10.

[0073] In a cross section perpendicular to the longitudinal axis direction x, the cross-sectional shape of the straight pipe section 23 preferably has a plurality of convex portions 30. When the cross-sectional shape of the straight pipe section 23 has a plurality of convex portions 30, it becomes easier to control the positions of the straight pipe section 23 where the wing-shaped portions are formed when the balloon 10 is in a deflated state.

[0074] In a cross section perpendicular to the longitudinal axis direction x, the number of convex portions 30 possessed by the cross-sectional shape of the straight pipe section 23 is preferably two or more, and more preferably three or more. By setting the lower limit of the number of convex portions 30 possessed by the cross-sectional shape of the straight pipe section 23 within the above range, the outer diameter of the balloon 10 can be reduced when the balloon 10 is deflated to fold the wing-shaped portions. Furthermore, the number of convex portions 30 possessed by the cross-sectional shape of the straight pipe section 23 is preferably ten or less, more preferably eight or less, even more preferably six or less, and even more preferably four or less. By setting the upper limit of the number of convex portions 30 possessed by the cross-sectional shape of the straight pipe section 23 within the above range, it is possible to prevent the number of wing-shaped portions formed when the balloon 10 is deflated from becoming too large, and to make it easier to fold the wing-shaped portions along the circumferential direction z. In particular, in a cross section perpendicular to the longitudinal axis direction x, the number of convex portions 30 possessed by the cross-sectional shape of the straight pipe section 23 is most preferably three.

[0075] When the cross-sectional shape of the straight pipe section 23 has multiple protrusions 30 in a cross section perpendicular to the longitudinal axis direction x, the sizes and shapes of the multiple protrusions 30 in the longitudinal axis direction x, radial direction y, and circumferential direction z may be the same or different.

[0076] As shown in Figures 2 and 4, when a first pressure is applied to the balloon 10, the angle θ5 formed by a line L7 passing through the centroid P9 of the cross-sectional shape of the balloon 10 perpendicular to the longitudinal axis direction x at the distal end 23d of the straight tube section 23 and the apex P10 of the convex portion 30, and a line L8 passing through the centroid P11 of the cross-sectional shape of the balloon 10 perpendicular to the longitudinal axis direction x at the proximal end 23p of the straight tube section 23 and the apex P12 of the convex portion 30, is preferably smaller than at least one of the angles θ1 and θ2.

[0077] When the cross-sectional shape of the straight pipe section 23 perpendicular to the longitudinal axis direction x has multiple convex sections 30, the apex of one convex section 30 at the distal end 23d of the straight pipe section 23 is apex P10, and the apex of the one convex section 30 at the proximal end 23p of the straight pipe section 23 is apex P12. In other words, apex P10 and apex P12 are apexes that exist in the same convex section 30 of the straight pipe section 23.

[0078] In Fig. 2, a line L7 passing through a centroid P9 of the cross-sectional shape of the balloon 10 perpendicular to the longitudinal axis direction x at the distal end 23d of the straight tube section 23 and a vertex P10 of the convex portion 30 is shown by a dashed line, and an angle θ5 is indicated. In Fig. 4, a line L8 passing through a centroid P11 of the cross-sectional shape of the balloon 10 perpendicular to the longitudinal axis direction x at the proximal end 23p of the straight tube section 23 and a vertex P12 of the convex portion 30 is shown by a dashed line, and an angle θ5 is indicated.

[0079] In addition, when the cross-sectional shape of the straight tube section 23 perpendicular to the longitudinal axis direction x has multiple convex portions 30, the angle θ5 is measured at the convex portion 30 where the angle θ5 is largest by drawing a line L7 passing through the centroid P9 and vertex P10 of the cross-sectional shape of the balloon 10 at the distal end 23d of the straight tube section 23, and a line L8 passing through the centroid P11 and vertex P12 of the cross-sectional shape of the balloon 10 at the proximal end 23p of the straight tube section 23.

[0080] When a first pressure is applied to the balloon 10, the angle θ5 formed by the lines L7 and L8 in the straight tube section 23 is smaller than at least one of the angle θ1 formed by the lines L1 and L2 in the proximal tapered section 22 and the angle θ2 formed by the lines L3 and L4 in the distal tapered section 24. As a result, the degree of twist of the apex of the convex portion 30, including the apexes P10 and P12, in the straight tube section 23 is smaller than at least one of the degree of twist of the apex of the convex portion 30, including the apexes P2 and P4, in the proximal tapered section 22 and the degree of twist of the apex of the convex portion 30, including the apexes P6 and P8, in the distal tapered section 24. In other words, the twist of the apex of the convex portion 30 in the straight tube section 23 is smaller than at least one of the proximal tapered section 22 and the distal tapered section 24, or is not twisted. As a result, the balloon 10 has less twist or no twist in the straight tube section 23 than in the proximal tapered section 22 or the distal tapered section 24, which increases the expansion force of the straight tube section 23 during expansion of the balloon 10 and makes it easier to expand the narrowed area. Furthermore, because the degree of twist of the apexes, including apexes P10 and P12, of the convex portions 30 in the straight tube section 23 is smaller than at least one of the degree of twist of the apexes, including apexes P2 and P4, of the convex portions 30 in the proximal tapered section 22 and the degree of twist of the apexes, including apexes P6 and P8, of the convex portions 30 in the distal tapered section 24, the wing-shaped portions 11 of the straight tube section 23 are less likely to stand up when the balloon 10 passes through the narrowed area, facilitating smooth insertion.

[0081] When the first pressure is applied to the balloon 10, the angle θ5 at the straight tubular section 23 is preferably smaller than the angle θ1 at the proximal tapered section 22 and the angle θ2 at the distal tapered section 24. That is, the angle θ5 between the lines L7 and L8 at the straight tubular section 23 is preferably smaller than both the angle θ1 between the lines L1 and L2 at the proximal tapered section 22 and the angle θ2 between the lines L3 and L4 at the distal tapered section 24. By making the angle θ5 smaller than both the angles θ1 and θ2, the shape of the straight tubular section 23 is less twisted during inflation of the balloon 10, thereby increasing the expansive force, and the side surfaces of the wing-shaped portions at both the proximal tapered section 22 and the distal tapered section 24 are more likely to come into contact with the wall of the biological lumen during deflation, allowing the balloon 10 to be easily folded in a wrapped manner.

[0082] 8 , when the balloon 10 is observed from the direction toward the longitudinal axis direction x from the apexes P10 and P12 of the convex portions 30 in a state in which the first pressure is applied to the balloon 10, it is preferable that a line L9 passing through the apex P10 of the convex portions 30 at the distal end 23d of the straight pipe portion 23 and the apex P12 of the convex portions 30 at the proximal end 23p of the straight pipe portion 23 does not intersect with the longitudinal axis direction x. In other words, it is preferable that in the straight pipe portion 23, a line L9 passing through the apex P10 of the convex portions 30 at the distal end 23d of the straight pipe portion 23 and the apex P12 of the convex portions 30 at the proximal end 23p of the straight pipe portion 23 is parallel to the longitudinal axis direction x.

[0083] When the first pressure is applied to the balloon 10, a straight line L9 passing through the apex P10 of the convex portion 30 at the distal end 23d of the straight tube portion 23 and the apex P12 of the convex portion 30 at the proximal end 23p of the straight tube portion 23 does not intersect with the longitudinal axis direction x, so that the convex portion 30 of the straight tube portion 23 is parallel to the longitudinal axis direction x and is not twisted. Therefore, when the balloon 10 is inflated, the inflation force of the balloon 10 is increased, making it easier to dilate the stricture.

[0084] 8, when the first pressure is applied to the balloon 10, the apex P10 of the convex portion 30 at the distal end 23d of the straight pipe portion 23 is preferably at the same circumferential position as the apex P12 of the convex portion 30 at the proximal end 23p of the straight pipe portion 23. This results in the convex portion 30 of the straight pipe portion 23 being parallel to the longitudinal axis direction x and not twisted.

[0085] 2 to 5, when a first pressure is applied to the balloon 10, the cross-sectional shapes of the straight tube section 23, the proximal tapered section 22, and the distal tapered section 24 perpendicular to the longitudinal axis direction x are preferably polygonal. When the first pressure is applied to the balloon 10, the cross-sectional shapes of the straight tube section 23, the proximal tapered section 22, and the distal tapered section 24 are polygonal, so that the corners of the polygonal cross-sectional shape of the balloon 10 tend to become the apexes of wing-shaped portions when the balloon 10 is deflated. This makes it easier to control the locations where wing-shaped portions are formed when the balloon 10 is deflated, allowing the balloon 10 to be easily folded so that the outer diameter of the balloon 10 is reduced.

[0086] Examples of polygonal cross-sectional shapes of the balloon 10 include triangles, rectangles, pentagons, and hexagons. The polygon may be a convex polygon with all interior angles equal to or less than 180 degrees, or a concave polygon with at least one interior angle greater than 180 degrees and less than 360 degrees. Polygons include polygons with clearly defined corners and straight sides, as well as rounded polygons with rounded corners and polygons with at least some curved sides. It is particularly preferred that the cross-sectional shapes of the straight tube section 23, proximal tapered section 22, and distal tapered section 24 perpendicular to the longitudinal axis direction x when a first pressure is applied to the balloon 10 be triangles, rectangles, pentagons, or hexagons. When the first pressure is applied inside the balloon 10, the cross-sectional shapes of the straight tube section 23, the proximal tapered section 22, and the distal tapered section 24 are either triangular, rectangular, pentagonal, or hexagonal, which makes it easier for the positions of the wing-shaped sections formed when the balloon 10 is contracted to be uniform in the circumferential direction z, making it easier to fold the balloon 10 so that its outer diameter becomes smaller.

[0087] 13 to 16 , when a second pressure of 2.0 atm + 1 atm (atmospheric pressure) is applied to the balloon 10, the cross-sectional shapes of the straight tube section 23, the proximal tapered section 22, and the distal tapered section 24 perpendicular to the longitudinal axis direction x are preferably circular. That is, when a first pressure of 0.5 atm + 1 atm (atmospheric pressure) or more and 1.0 atm + 1 atm (atmospheric pressure) or less is applied to the balloon 10, the cross-sectional shapes of the straight tube section 23, the proximal tapered section 22, and the distal tapered section 24 are preferably polygonal, and when a second pressure of 2.0 atm + 1 atm (atmospheric pressure), which is higher than the first pressure, is applied, the cross-sectional shapes of the straight tube section 23, the proximal tapered section 22, and the distal tapered section 24 are preferably circular.

[0088] When a first pressure is applied to the balloon 10, the cross-sectional shapes of the straight tube section 23, the proximal tapered section 22, and the distal tapered section 24 perpendicular to the longitudinal axis direction x are polygonal. When a second pressure is applied to the balloon 10, the cross-sectional shapes of the straight tube section 23, the proximal tapered section 22, and the distal tapered section 24 perpendicular to the longitudinal axis direction x are circular. This makes it easier to fold the balloon 10 so that the outer diameter becomes smaller by controlling the location where the wing-shaped sections are formed when the balloon 10 is contracted. When a high pressure is applied to the balloon 10, the cross-sectional shapes of the straight tube section 23, the proximal tapered section 22, and the distal tapered section 24 become circular, making it easier to apply pressure evenly throughout the entire circumferential direction z, and allowing for efficient expansion of the narrowed area.

[0089] 17 and 18 , the balloon 10 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. The cross-sectional shapes of the proximal sleeve portion 21 and the distal sleeve portion 25 perpendicular to the longitudinal axis direction x are preferably circular. The circular cross-sectional shapes of the proximal sleeve portion 21 and the distal sleeve portion 25 perpendicular to the longitudinal axis direction x result in smooth outer surfaces of the proximal sleeve portion 21 and the distal sleeve portion 25, which are non-expandable portions of the balloon 10 that do not form wing-shaped portions. Therefore, both when the balloon 10 is pushed distally and when it is pulled proximally, the proximal sleeve portion 21 and the distal sleeve portion 25 are less likely to be damaged if they come into contact with other objects, resulting in a highly safe balloon 10. Furthermore, since the cross-sectional shapes perpendicular to the longitudinal axis direction x of the proximal sleeve portion 21 and the distal sleeve portion 25 are circular, assembly processing in the manufacture of the balloon catheter 1 is easier, thereby enabling increased manufacturing efficiency.

[0090] The balloon catheter 1 according to the embodiment of the present disclosure includes the balloon 10 for the balloon catheter 1 described above.

[0091] As shown in FIG. 19 , a balloon catheter 1 having a balloon 10 according to an embodiment of the present disclosure preferably includes 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 a fluid through the lumen of the shaft 140 and deflated by discharging the fluid. To control the expansion and contraction of the balloon 10, an indeflator (a balloon pressurizer) can be used to introduce or discharge the fluid. The fluid may be, for example, saline or a mixture of a contrast agent and saline. The fluid may also be a pressurized fluid pressurized by a pump or the like.

[0092] 19 shows a so-called rapid exchange type balloon catheter 1 having a guidewire port 150 midway from the distal side to the proximal side of the shaft 140 and an inner shaft 160 that functions as a guidewire passage from the guidewire port 150 to the distal side of the shaft 140. The balloon catheter 1 preferably has a proximal shaft 141 and a distal shaft 142. The proximal shaft 141 and the distal shaft 142 may be separate members, and the proximal end of the distal shaft 142 may be connected to the distal end of the proximal shaft 141 to form the shaft 140 that extends from the balloon 10 to the proximal end of the balloon catheter 1. Alternatively, a single shaft 140 may extend from the balloon 10 to the proximal end of the balloon catheter 1, or the proximal shaft 141 and the distal shaft 142 may be composed of multiple tubular members.

[0093] The shaft 140 preferably has a fluid flow path and a guidewire insertion path therein. To configure the shaft 140 to have a fluid flow path and a guidewire insertion path therein, for example, an inner shaft 160 disposed inside the shaft 140 may function as a guidewire insertion path, and the space between the shaft 140 and the inner shaft 160 may function as a fluid flow path. In such a configuration, it is preferable that the inner shaft 160 extends from the distal end of the shaft 140 and passes through 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.

[0094] The shaft 140 is preferably made of resin, metal, or a combination of resin and metal. Using a resin as the material for the shaft 140 makes it easier to impart flexibility and elasticity to the shaft 140. Furthermore, using a metal as the material for the shaft 140 can improve the deliverability of the balloon catheter 1. Examples of resins that can be used to make the shaft 140 include polyamide resins, polyester resins, polyurethane resins, polyolefin resins, fluorine-containing resins, vinyl chloride resins, silicone resins, natural rubber, and synthetic rubber. These may be used alone or in combination. Examples of metals that can be used to make the shaft 140 include stainless steels such as SUS304 and SUS316, platinum, nickel, cobalt, chromium, titanium, tungsten, gold, Ni-Ti alloys, Co-Cr alloys, and combinations thereof. When the shaft 140 is composed of the proximal shaft 141 and the distal shaft 142 which are separate members, for example, the proximal shaft 141 may be made of resin and the distal shaft 142 may be made of metal. The shaft 140 may also have a laminated structure made of different materials or the same material.

[0095] The balloon 10 and the shaft 140 can be joined by bonding with an adhesive, welding, or by attaching a ring-shaped member to the overlapping portion of the end of the balloon 10 and the shaft 140 and crimping the end. Among these, it is preferable that the balloon 10 and the shaft 140 are joined by welding. By welding the balloon 10 and the shaft 140 together, the bond between the balloon 10 and the shaft 140 is less likely to come undone even when the balloon 10 is repeatedly expanded or contracted, thereby improving the bond strength.

[0096] A tip member 170 is preferably 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 as a separate member from the inner shaft 160 and connected to the distal end of the balloon 10, or the inner shaft 160 may extend distally beyond the distal end of the balloon 10 and function as the tip member 170.

[0097] Radiopaque markers 180 may be placed on the inner shaft 160 inside the balloon 10 at the location where the balloon 10 is located in the longitudinal axis direction x so that the position of the balloon 10 can be confirmed under X-ray fluoroscopy. The radiopaque markers 180 are preferably placed at positions corresponding to both ends of the straight tube portion of the balloon 10, or may be placed at a position corresponding to the center of the straight tube portion of the balloon 10 in the longitudinal axis direction x.

[0098] The number of radiopaque markers 180 is not particularly limited, and may be one or more. The shape of the radiopaque marker 180 is not particularly limited, and examples thereof include a cylindrical shape, a polygonal cylindrical shape, or a C-shaped cross section with a notch in the cylinder, and a coil shape with a wound wire. Among these, the shape of the radiopaque marker 180 is preferably cylindrical.

[0099] Examples of materials that can be used to form the radiopaque marker 180 include radiopaque materials such as lead, barium, iodine, tungsten, gold, platinum, iridium, stainless steel, titanium, and cobalt-chromium alloys.

[0100] A hub 5 may be provided on the proximal side of the shaft 140, and the hub 5 preferably has a fluid injection section 6 that communicates with a flow path for fluid supplied inside the balloon 10.

[0101] The shaft 140 and the hub 5 can be joined by, for example, bonding with an adhesive or welding. Among these, it is preferable that the shaft 140 and the hub 5 are joined by adhesive. By bonding the shaft 140 and the hub 5, the bond strength between the shaft 140 and the hub 5 can be increased, thereby improving the durability of the balloon catheter 1, even when the shaft 140 and the hub 5 are made of different materials, for example, when the shaft 140 is made of a highly flexible material and the hub 5 is made of a highly rigid material.

[0102] Although not shown, the present disclosure can also be applied to so-called over-the-wire balloon catheters, which have a guidewire passage extending from the distal side to the proximal side of the shaft. In the case of an over-the-wire balloon catheter, the inflation lumen and the guidewire lumen preferably extend to a hub located on the proximal side, and the proximal openings of each lumen are preferably provided in a bifurcated hub.

[0103] In the case of a rapid exchange type catheter, it is preferable that an appropriate coating is applied to the outer wall of at least one of the proximal shaft 141 and the distal shaft 142, and it is more preferable that a coating is applied to both the proximal shaft 141 and the distal shaft 142. In the case of an over-the-wire type catheter, it is preferable that an appropriate coating is applied to the outer wall of the outer shaft.

[0104] The coating can be a hydrophilic coating or a hydrophobic coating depending on the purpose, and can be applied by dipping the shaft 140 in a hydrophilic or hydrophobic coating agent, by applying a hydrophilic or hydrophobic coating agent to the outer wall of the shaft 140, or by covering the outer wall of the shaft 140 with a hydrophilic or hydrophobic coating agent. The coating agent may contain drugs or additives.

[0105] Examples of hydrophilic coating agents include hydrophilic polymers such as polyvinyl alcohol, polyethylene glycol, polyacrylamide, polyvinylpyrrolidone, methyl vinyl ether maleic anhydride copolymer, and the like, or hydrophilic coating agents made from any combination thereof.

[0106] Examples of hydrophobic coating agents include polytetrafluoroethylene (PTFE), fluorinated ethylene propylene (FEP), perfluoroalkoxyalkane (PFA), silicone oil, hydrophobic urethane resin, carbon coat, diamond coat, diamond-like carbon (DLC) coat, ceramic coat, and substances terminated with alkyl groups or perfluoroalkyl groups and having low surface free energy.

[0107] This application claims the benefit of priority based on Japanese Patent Application No. 2024-129202, filed on August 5, 2024. The entire contents of the specification of Japanese Patent Application No. 2024-129202, filed on August 5, 2024, are incorporated herein by reference.

[0108] 1: Balloon catheter 5: Hub 6: Fluid injection section 10: Balloon 21: Proximal sleeve section 22: Proximal tapered section 22d: Distal end of proximal tapered section 22p: Proximal end of proximal tapered section 23: Straight tube section 23d: Distal end of straight tube section 23p: Proximal end of straight tube section 24: Distal tapered section 24d: Distal end of distal tapered section 24p: Proximal end of distal tapered section 25: Distal sleeve section 30: Convex section 40: Concave section 140: Shaft 141: Proximal shaft 142: Distal shaft 150: Guidewire port 160: Inner shaft 170: Distal tip member 180: Radiopaque marker P1: Centroid of cross-sectional shape at the distal end of the proximal tapered section P2: Apex of the convex portion at the distal end of the proximal tapered portion P3: Centroid of the cross-sectional shape at the proximal end of the proximal tapered portion P4: Apex of the convex portion at the proximal end of the proximal tapered portion P5: Centroid of the cross-sectional shape at the proximal end of the distal tapered portion P6: Apex of the convex portion at the proximal end of the distal tapered portion P7: Centroid of the cross-sectional shape at the distal end of the distal tapered portion P8: Apex of the convex portion at the distal end of the distal tapered portion L1: A straight line passing through the centroid of the cross-sectional shape at the distal end of the proximal tapered portion and the apex of the convex portion L2: A straight line passing through the centroid of the cross-sectional shape at the proximal end of the proximal tapered portion and the apex of the convex portion L3: A straight line passing through the centroid of the cross-sectional shape at the proximal end of the distal tapered portion and the apex of the convex portion L4: A straight line passing through the centroid of the cross-sectional shape at the distal end of the distal tapered portion and the apex of the convex portion L5: a line passing through the apex of the convex portion at the distal end of the proximal tapered portion and the apex of the convex portion at the proximal end of the proximal tapered portion L6: a line passing through the apex of the convex portion at the proximal end of the distal tapered portion and the apex of the convex portion at the distal end of the distal tapered portion L7: a line passing through the centroid of the cross-sectional shape at the distal end of the straight pipe portion and the apex of the convex portion L8: a line passing through the centroid of the cross-sectional shape at the proximal end of the straight pipe portion and the apex of the convex portion L9: a line passing through the apex of the convex portion at the distal end of the straight pipe portion and the apex of the convex portion at the proximal end of the straight pipe portion θ1: the angle between the lines L1 and L2 θ2: the angle between the lines L3 and L4 θ3: the angle between the line L5 and the longitudinal axis direction x θ4: the angle between the line L6 and the longitudinal axis direction x θ5: the angle between the lines L7 and L8

Claims

1. A balloon for a balloon catheter having a longitudinal axis direction extending from the proximal side to the distal side, a radial direction perpendicular to the longitudinal axis direction, and a circumferential direction, wherein the balloon has a straight tube section, a proximal tapered section located proximal to the straight tube section, and a distal tapered section located distal to the straight tube section, wherein, when a first pressure of 0.5 atm + 1 atm (atmospheric pressure) or more and 1.0 atm + 1 atm (atmospheric pressure) or less is applied to the balloon, the cross-sectional shape of the proximal tapered section and the cross-sectional shape of the distal tapered section perpendicular to the longitudinal axis direction each have a convex portion protruding outward from the balloon, and wherein, when the first pressure is applied to the balloon, the balloon for a balloon catheter satisfies at least one of the following [Condition 1] and [Condition 2]. [Condition 1] The angle θ1 formed by a line passing through the centroid of the cross-sectional shape of the balloon perpendicular to the longitudinal axis direction at the distal end of the proximal tapered portion and the apex of the convex portion and a line passing through the centroid of the cross-sectional shape of the balloon perpendicular to the longitudinal axis direction at the proximal end of the proximal tapered portion and the apex of the convex portion is greater than 0 degrees. [Condition 2] The angle θ2 formed by a line passing through the centroid of the cross-sectional shape of the balloon perpendicular to the longitudinal axis direction at the proximal end of the distal tapered portion and the apex of the convex portion and a line passing through the centroid of the cross-sectional shape of the balloon perpendicular to the longitudinal axis direction at the distal end of the distal tapered portion and the apex of the convex portion is greater than 0 degrees.

2. The balloon for a balloon catheter according to claim 1, which satisfies at least one of the following conditions 3 and 4 when the first pressure is applied to the balloon: [Condition 3] When observed from the apex of the convex portion in the direction of the longitudinal axis, a line passing through the apex of the convex portion at the distal end of the proximal tapered portion and the apex of the convex portion at the proximal end of the proximal tapered portion intersects the longitudinal axis. [Condition 4] When observed from the apex of the convex portion in the direction of the longitudinal axis, a line passing through the apex of the convex portion at the proximal end of the distal tapered portion and the apex of the convex portion at the distal end of the distal tapered portion intersects the longitudinal axis.

3. The balloon for a balloon catheter according to claim 2, wherein, when observed in a direction from the apex of the convex portion toward the longitudinal axis direction while the first pressure is applied to the balloon, at least one of the following angles θ3 formed by a line passing through the apex of the convex portion at the distal end of the proximal taper portion and the apex of the convex portion at the proximal end of the proximal taper portion, and the longitudinal axis direction, and the angle θ4 formed by a line passing through the apex of the convex portion at the proximal end of the distal taper portion and the apex of the convex portion at the distal end of the distal taper portion, and the longitudinal axis direction is greater than 0 degrees and less than 90 degrees.

4. A balloon for a balloon catheter as described in claim 1, wherein, when the first pressure is applied to the balloon, the cross-sectional shape of the straight tube section perpendicular to the longitudinal axis direction has the convex portion, and when the first pressure is applied to the balloon, the angle θ5 formed by a line passing through the centroid of the cross-sectional shape of the balloon perpendicular to the longitudinal axis direction at the distal end of the straight tube section and the apex of the convex portion and a line passing through the centroid of the cross-sectional shape of the balloon perpendicular to the longitudinal axis direction at the proximal end of the straight tube section and the apex of the convex portion is smaller than at least one of the angle θ1 and the angle θ2.

5. A balloon for a balloon catheter as described in claim 1, wherein, when the first pressure is applied to the inside of the balloon, the cross-sectional shapes of the straight tube section perpendicular to the longitudinal axis direction, the cross-sectional shapes of the proximal tapered section, and the cross-sectional shapes of the distal tapered section are polygonal, and when a second pressure of 2.0 atm + 1 atm (atmospheric pressure) is applied to the inside of the balloon, the cross-sectional shapes of the straight tube section perpendicular to the longitudinal axis direction, the cross-sectional shapes of the proximal tapered section, and the cross-sectional shapes of the distal tapered section are circular.

6. A balloon for a balloon catheter as described in 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 direction are circular.

7. A balloon catheter comprising a balloon for a balloon catheter according to any one of claims 1 to 6.

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