Balloon for balloon catheter and balloon catheter equipped therewith, and method for manufacturing a balloon catheter

Abstract

To provide a balloon for a balloon catheter that hardly causes positional deviation in the tip of a protruding part, and can improve incision efficiency for a narrow part.SOLUTION: A balloon for a balloon catheter including an outer layer 20b and an inner layer 20a composed of a material whose Shore D hardness is lower than that of the outer layer 20b includes a protruding part 28 protruding outward in a radial direction y1, and extending in a longitudinal axis direction x1. A region where the protruding part 28 is present in a cross section perpendicular to the longitudinal axis direction x1 in a straight piping section 23 includes a central part 29a including an apex 28T and end parts 29b positioned on both sides of the central part 29a. In the cross section perpendicular to the longitudinal axis direction x1 in the straight piping section 23, the thickness Ta of the inner layer 20a in the central part 29a is larger than the thickness Tb of the inner layer 20a in the end parts 29b.SELECTED DRAWING: Figure 2

Description

【Technical Field】 【0001】 The present invention relates to a balloon for a balloon catheter, a balloon catheter including the same, and a method for manufacturing a balloon catheter. 【Background Art】 【0002】 When a stenosis formed by calcification or the like is formed on the inner wall of a blood vessel, diseases such as angina pectoris and myocardial infarction are caused. As one of these treatments, there is angioplasty in which a stenosis is expanded using a balloon catheter. Angioplasty is a minimally invasive treatment that does not require a thoracotomy such as bypass surgery and is widely performed. 【0003】 In angioplasty, it may be difficult to expand a stenosis hardened by calcification or the like with a general balloon catheter. In addition, a method of expanding a stenosis by placing an indwelling expansion device called a stent in the stenosis is also used. However, for example, in some cases, an ISR (In-Stent-Restenosis) lesion or the like occurs in which neointima excessively grows in the blood vessel after this treatment and the blood vessel stenosis occurs again. In an ISR lesion, the neointima is soft and the surface is slippery, so that in a general balloon catheter, the position of the balloon may shift from the lesion part during balloon expansion and damage the blood vessel. 【0004】 As a balloon catheter capable of expanding a stenosis even in such lesions as calcified lesions and ISR lesions, a balloon catheter provided with protrusions, blades, or scoring elements for biting into the stenosis on the balloon has been developed. For example, Patent Document 1 discloses a balloon catheter in which an amorphous polymer is used for the protrusion to make the rigidity of the protrusion larger than that of the balloon wall and improve the incision efficiency by the protrusion. 【Prior Art Documents】 【Patent Documents】 【0005】 [Patent Document 1] U.S. Patent Application Publication No. 2016 / 0128718 [Overview of the Initiative] [Problems that the invention aims to solve] 【0006】 However, the conventional balloon described above had a drawback: when the balloon placed in the lesion was expanded, the position of the tip of the protrusion tended to shift, making it difficult to position the tip of the protrusion at the desired location in the stenosis for incision. 【0007】 In view of the above circumstances, the present invention aims to provide a balloon for a balloon catheter that is less prone to misalignment of the tip of the protruding part and can improve the efficiency of cutting the stenotic part, a balloon catheter equipped with the same, and a method for manufacturing a balloon catheter. [Means for solving the problem] 【0008】 The balloon for a balloon catheter according to an embodiment of the present invention that solves the above problems is as follows. [1] A balloon for a balloon catheter having longitudinal, radial, and circumferential directions, and comprising an outer layer and an inner layer made of a material with a lower Shore D hardness than the outer layer, It has a straight pipe section, a proximal tapered section located proximal to the straight pipe section, a proximal sleeve section located proximal to the proximal tapered section, a distal tapered section located distal to the straight pipe section, and a distal sleeve section located distal to the distal tapered section. It has a projection that protrudes radially outward and extends in the longitudinal direction, In the cross-section perpendicular to the longitudinal axis of the straight pipe section, the region where the protrusion exists has a central portion including the top of the protrusion, and ends located on both sides of the central portion in the circumferential direction. A balloon catheter balloon in which, in a cross-section perpendicular to the longitudinal axis in the straight tube portion, the thickness of the inner layer in the central portion is greater than the thickness of the inner layer at the end portion. [2] In the straight tube portion, in a cross section perpendicular to the longitudinal axis, the thickness of the inner layer in the central portion is smaller than the thickness of the outer layer in the central portion. [1] A balloon for a balloon catheter. [3] In a cross section perpendicular to the longitudinal axis direction in the straight tube portion, the ratio of the thickness of the outer layer to the thickness of the inner layer in the central portion (thickness of the outer layer in the central portion / thickness of the inner layer in the central portion) is greater than the ratio of the thickness of the outer layer to the thickness of the inner layer at the end portion (thickness of the outer layer at the end portion / thickness of the inner layer at the end portion) [1] or [2] balloon for balloon catheter. [4] In a cross section perpendicular to the longitudinal axis in at least one of the proximal tapered portion and the distal tapered portion, the thickness of the inner layer in the central portion is greater than the thickness of the inner layer at the end portion. [1] to [3] A balloon for a balloon catheter according to any one of these. [5] The balloon for a balloon catheter according to any one of [1] to [4], wherein the thickness of the inner layer in the central part of a cross section perpendicular to the longitudinal axis in at least one of the proximal tapered portion and the distal tapered portion is greater than the thickness of the inner layer in the central part of a cross section perpendicular to the longitudinal axis in the straight tube portion. [6] In a cross section perpendicular to the longitudinal axis in at least one of the proximal sleeve portion and the distal sleeve portion, the thickness of the inner layer in the central portion is greater than the thickness of the inner layer at the end portion. [1] to [5] A balloon for a balloon catheter according to any one of these. [7] The balloon for a balloon catheter according to any one of [1] to [6], wherein the thickness of the inner layer in the central part of a cross section perpendicular to the longitudinal axis in at least one of the proximal sleeve portion and the distal sleeve portion is greater than the thickness of the inner layer in the central part of a cross section perpendicular to the longitudinal axis in the straight tube portion. 【0009】 The present invention also provides the following: [8] A balloon catheter equipped with a balloon for a balloon catheter as described in any of [1] to [7] above. 【0010】 The present invention further provides a method for manufacturing a balloon catheter as described in [8]. A manufacturing method according to an embodiment of the present invention is as follows. [9] A method for manufacturing a balloon catheter as described in [8] above, The steps include preparing a parison having radial, circumferential, and longitudinal axis directions, and having a lumen extending in the longitudinal axis direction, The method includes the step of biaxially extending the parison to produce a balloon having a proximal sleeve portion, a proximal tapered portion, a straight tube portion, a distal tapered portion, and a distal sleeve portion, and having a projection that protrudes radially outward and extends in the longitudinal axis direction, The aforementioned parison is, It has an outer layer and an inner layer made of a material with a lower Shore D hardness than the outer layer. It has a protruding region including a protruding portion that protrudes radially outward and extends in the longitudinal direction, and a non-protruding region other than the protruding region. A method for manufacturing a balloon catheter, wherein in a cross section perpendicular to the longitudinal axis, the inner layer has a small thickness portion in the non-protruding region and a large thickness portion in the protruding region having a thickness greater than the thickness of the small thickness portion. [Effects of the Invention] 【0011】 The balloon for a balloon catheter and the balloon catheter equipped therewith, as well as the method for manufacturing a balloon catheter, provide a balloon for a balloon catheter and the balloon catheter equipped therewith, and a method for manufacturing a balloon catheter, which are less prone to displacement of the tip of the protruding part and can improve the efficiency of incising the stenotic portion. This makes it possible to efficiently incise the stenotic portion while improving the safety of treatment and procedures using a balloon catheter. [Brief explanation of the drawing] 【0012】 [Figure 1] Shows a side view of a balloon catheter according to an embodiment of the present invention. [Figure 2] Shows a cross-sectional view taken along line II-II of the balloon catheter shown in FIG. 1. [Figure 3] Shows a cross-sectional view taken along line III-III of the balloon catheter shown in FIG. 1. [Figure 4] Shows a cross-sectional view taken along line IV-IV of the balloon catheter shown in FIG. 1. [Figure 5] Shows a perspective view of a parison before biaxial stretching according to an embodiment of the present invention. [Figure 6] Shows a cross-sectional view taken along line VI-VI of the parison shown in FIG. 5. [Figure 7] Shows a cross-sectional view perpendicular to the longitudinal axis of the parison mold used in the production of the parison shown in FIG. 6. [Figure 8] Shows a cross-sectional view in the longitudinal axis direction of the mold used for biaxial stretching of the parison in the manufacturing method according to an embodiment of the present invention. [Figure 9] Shows a cross-sectional view taken along line IX-IX of the mold shown in FIG. 8. 【Mode for Carrying Out the Invention】 【0013】 Hereinafter, the present invention will be described based on embodiments. However, the present invention is not limited by the following embodiments, and it is of course possible to appropriately modify and implement it within the range that can conform to the gist of the foregoing and following descriptions, and all of them are included in the technical scope of the present invention. In each drawing, for the sake of convenience, hatching, member numbers, etc. may be omitted, but in such cases, reference shall be made to the specification and other drawings. Also, the dimensions of various members in the drawings may differ from the actual dimensions because priority is given to facilitating understanding of the features of the present invention. 【0014】 1. Balloon for Balloon Catheter A balloon for a balloon catheter according to an embodiment of the present invention has longitudinal, radial, and circumferential directions, and comprises an outer layer and an inner layer made of a material with a lower Shore D hardness than the outer layer, and comprises a straight tube portion, a proximal tapered portion located proximal to the straight tube portion, a proximal sleeve portion located proximal to the proximal tapered portion, a distal tapered portion located distal to the straight tube portion, and a distal sleeve portion located distal to the distal tapered portion, and has a projection that protrudes radially outward and extends in the longitudinal direction, and in a cross section perpendicular to the longitudinal direction of the straight tube portion, the region where the projection exists has a central portion including the top of the projection and ends located on both sides in the circumferential direction of the central portion, and in a cross section perpendicular to the longitudinal direction of the straight tube portion, the thickness of the inner layer in the central portion is greater than the thickness of the inner layer at the ends. 【0015】 Dilatation of a stenosis using a balloon catheter is performed by inserting the balloon, located at the distal end of the balloon catheter, into the lumen of the blood vessel and delivering it to the stenosis. The balloon is then expanded, and the projection located radially outward of the balloon is pressed into the stenosis, thereby incising it. The balloon for the balloon catheter described above has an outer layer and an inner layer made of a material with a lower Shore D hardness than the outer layer. The thickness of the inner layer is greater in the central part, including the top of the projection, than in the ends located on either side of the central part of the projection, thus enhancing the cushioning effect of the central part of the projection. As a result, when the balloon delivered to the lesion is expanded and the top of the projection contacts the stenosis, the central part of the projection can more easily absorb the resistance force that the top of the projection receives from the wall of the stenosis, making displacement of the top of the projection less likely and allowing the projection to incise the desired location of the stenosis. This makes it possible to efficiently incise the stenosis while improving the safety of treatment and procedures using a balloon catheter. 【0016】 When inserting a balloon into a narrowed area or removing it from the body, the balloon's outer diameter can be reduced by expelling fluid from its lumen to cause it to deflate and wrapping the fin-shaped portion of the balloon around the shaft. At this time, the protrusions on the balloon's expansion portion are covered by the fin-shaped portion, preventing damage caused by the protrusions contacting the vascular lumen wall. 【0017】 In this specification, balloons for balloon catheters may be simply referred to as "balloons." 【0018】 Hereinafter, a balloon for a balloon catheter according to an embodiment of the present invention will be described with reference to Figures 1 to 4. Figure 1 is a side view of a balloon catheter according to one embodiment of the present invention. Figure 2 shows a cross-sectional view taken along line II-II of the balloon catheter shown in Figure 1, and represents a cross-sectional view perpendicular to the longitudinal axis direction of the straight tube portion. Figure 3 shows a cross-sectional view taken along line III-III of the balloon catheter shown in Figure 1, and represents a cross-sectional view perpendicular to the longitudinal axis direction of the distal tapered portion. Figure 4 shows a cross-sectional view taken along line IV-IV of the balloon catheter shown in Figure 1, and represents a cross-sectional view perpendicular to the longitudinal axis direction of the distal sleeve portion. 【0019】 As shown in Figure 1, balloon 2 is used in balloon catheter 1. Balloon 2 is connected to the distal end of shaft 30, and balloon 2 can be expanded by introducing fluid through the lumen of shaft 30 and deflated by expelling the fluid. To control the expansion and contraction of balloon 2, an indeflerator (balloon pressurizer) can be used to introduce or expel fluid. The fluid may be pressurized fluid pressurized by a pump or the like. Balloon catheter 1 will be described in detail in section "2. Balloon Catheter". 【0020】 The balloon 2 has a longitudinal axis direction x1, a radial direction y1 connecting the centroid of the outer edge of the balloon 2 and a point on the outer edge in a cross section perpendicular to the longitudinal axis direction x1, and a circumferential direction z1 along the outer edge of the balloon 2 in a cross section perpendicular to the longitudinal axis direction x1. In this specification, the direction toward the user's hand in the longitudinal axis direction x1 is referred to as the proximal side, and the opposite side from the proximal side, i.e., the direction toward the person being treated, is referred to as the distal side. 【0021】 Each component and part other than balloon 2 has a longitudinal axis direction, a radial direction, and a circumferential direction, which may or may not be the same as the longitudinal axis direction x1, radial direction y1, and circumferential direction z1 of balloon 2. However, for the sake of clarity, in this specification, all components and parts are described as having the same longitudinal axis direction x1, radial direction y1, and circumferential direction z1 as balloon 2. 【0022】 As shown in Figures 1 to 4, the balloon 2 has a projection 28 that protrudes outward in the radial direction y1 and extends in the longitudinal direction x1. The projection 28 is formed to be thicker than the portion of the balloon 2 in which the projection 28 is not provided. In other words, as shown in Figures 2 to 4, the projection 28 can be described as the portion that protrudes outward in the radial direction y1 than the outer surface of the balloon body 20, which has the thickness of the portion of the balloon 2 in which the projection 28 is not provided. 【0023】 The thickness of the protruding portion 28 of the balloon 2 is preferably 1.2 times or more the thickness of the portion of the balloon 2 without the protruding portion 28, more preferably 1.5 times or more, and even more preferably 1.8 times or more, 2.0 times or more, or 2.5 times or more. The upper limit of the thickness of the protruding portion 28 of the balloon 2 is not particularly limited, and may be, for example, 30 times or less, 20 times or less, or 10 times or less the thickness of the portion of the balloon 2 without the protruding portion 28. 【0024】 The balloon body portion 20 defines the basic shape of the balloon 2, and the protrusions 28 are preferably provided on the outer surface of the balloon body portion 20 in any pattern such as linear, dotted, mesh-like, or spiral. The protrusions 28 give the balloon 2 a scoring function, and the balloon 2 can be used to create cracks in calcified stenoses and expand them during angioplasty. In addition, the protrusions 28 can also contribute to improving the strength of the balloon 2 and suppressing over-expansion during pressurization. 【0025】 As shown in Figures 2 to 4, there may be multiple protrusions 28 in the circumferential direction z1, or there may be only one. The number of protrusions 28 in the circumferential direction z1 may be 1 or more, 2 or more, 3 or more, 4 or more, 6 or more, or 20 or less, 15 or less, or 10 or less. When there are multiple protrusions 28 in the circumferential direction z1, it is preferable that the multiple protrusions 28 are spaced apart in the circumferential direction z1, and more preferably that they are arranged at equal intervals in the circumferential direction z1. The spacing distance is preferably longer than the maximum circumferential length of the protrusions 28. 【0026】 The cross-sectional shape of the projection 28 in a section perpendicular to the longitudinal axis x1 may be arbitrary, for example, a triangle, quadrilateral, polygon, semicircle, part of a circle, roughly circular, sector, wedge, convex shape, spindle shape, or a combination thereof. Note that triangles, quadrilaterals, and polygons include not only those with clearly defined corner vertices and straight edges, but also so-called rounded polygons with rounded corners, and those with at least a portion of their edges being curved. Alternatively, the cross-sectional shape of the projection 28 may be an irregular shape with irregularities or notches. 【0027】 If the projection 28 is formed in a linear or dot shape, it is preferable that the projection 28 is arranged to extend along the longitudinal axis x1. Alternatively, the projection 28 may be arranged to extend spirally around the longitudinal axis. 【0028】 Although not shown in the figures, the balloon 2 may have an inner projection that protrudes inward in the radial direction y1. Preferably, the inner projection extends in the longitudinal axis direction x1. Preferably, the projection 28 and the inner projection are located at the same position in the longitudinal direction x1 and the circumferential direction z1 of the balloon 2, and preferably they are integrally formed. The balloon 2 may have the projection 28 and the inner projection by integrally forming the projection 28, the balloon body 20 and the inner projection as a single thick unit. 【0029】 The balloon 2 has an outer layer 20b and an inner layer 20a located radially inward from the outer layer 20b and made of a material with a lower Shore D hardness than the outer layer 20b. Preferably, the balloon 2 has a two-layer structure consisting of the inner layer 20a and the outer layer 20b in all parts. More specifically, it is preferable that the inner layer 20a and the outer layer 20b are continuous over the entire 360 ​​degrees of the circumferential direction z1 at any position in the longitudinal axis direction x1. Because the balloon 2 has a two-layer structure consisting of the inner layer 20a and the outer layer 20b in all parts, the outer surface of the balloon 2 is formed of the outer layer 20b with a high Shore D hardness, so the outer surface of the balloon 2 is less susceptible to damage and its strength can be improved. In addition, since the outer surface of the protrusion 28 is also formed of the outer layer 20b with a high Shore D hardness, the scoring function of the protrusion 28 can be enhanced. 【0030】 The Shore D hardness of the inner layer 20a is preferably 20 or higher, 25 or higher, 30 or higher, 35 or higher, or 40 or higher, and also preferably 70 or lower, 65 or lower, 60 or lower, or 55 or lower. The Shore D hardness of the outer layer 20b is preferably greater than 70, 72 or higher, 74 or higher, or 75 or higher, and also preferably 90 or lower, 85 or lower, or 80 or lower. If the Shore D hardness of the inner layer 20a is within the above range, it can contribute to improving the flexibility of the balloon 2. If the Shore D hardness of the outer layer 20b is within the above range, it can contribute to improving the strength of the balloon 2 and improving the scoring function of the protrusion 28. 【0031】 Shore D hardness can be measured, for example, using a Type D durometer based on the description in JIS K6253-2:2012. Furthermore, the Shore D hardness of the inner layer 20a and the outer layer 20b may be the Shore D hardness of the material at the stage before it is molded into the balloon 2. 【0032】 Suitable materials for the outer layer 20b include polyamide resins such as nylon 11 and nylon 12; polyester resins such as polyethylene terephthalate and polybutylene terephthalate; and polyurethane resins. For the inner layer 20a, a thermoplastic elastomer is preferred from the viewpoint of low Shore D hardness; for example, a polyamide elastomer such as a polyether block amide copolymer is preferred. 【0033】 As shown in Figure 1, the balloon 2 has a proximal end and a distal end in the longitudinal axis direction x1, and comprises a straight tube section 23, a proximal tapered section 22 located proximal to the straight tube section 23, a proximal sleeve section 21 located proximal to the proximal tapered section 22, a distal tapered section 24 located distal to the straight tube section 23, and a distal sleeve section 25 located distal to the distal tapered section 24. The straight tube section 23 is preferably substantially cylindrical with approximately the same diameter in the longitudinal axis direction x1, but may have different diameters in the longitudinal axis direction x1. The proximal tapered section 22 and the distal tapered section 24 are preferably formed in a substantially conical or frustoconical shape, decreasing in diameter as they move away from the straight tube section 23. Because the straight section 23 has the largest diameter, when the balloon 2 is expanded in a lesion such as a stenosis, the straight section 23 can make sufficient contact with the lesion, making it easier to perform treatment such as dilation of the lesion. In addition, because the proximal tapered section 22 and the distal tapered section 24 are reduced in diameter, when the balloon 2 is deflated, the outer diameter of the proximal and distal ends of the balloon 2 can be reduced, thereby reducing the step between the shaft 30 and the balloon 2, making it easier to insert the balloon 2 into the body cavity. 【0034】 While the proximal tapered portion 22, the straight tube portion 23, and the distal tapered portion 24 are the parts that expand when fluid is introduced into the balloon 2, it is preferable that the proximal sleeve portion 21 and the distal sleeve portion 25 do not expand. This makes it possible to fix at least a part of the proximal sleeve portion 21 to the distal end of the shaft 30, and at least a part of the distal sleeve portion 25 to the inner shaft 60, which will be described later. 【0035】 Preferably, the balloon 2 has protrusions 28 in each region of the proximal sleeve portion 21, proximal tapered portion 22, straight tube portion 23, distal tapered portion 24, and distal sleeve portion 25. This allows the protrusions 28 provided in the straight tube portion 23 to contribute to improved scoring function, while the protrusions 28 provided in other regions can contribute to improving the strength of the balloon 2 and suppressing over-expansion during pressurization. 【0036】 As shown in Figure 2, in the straight tube section 23, the projection 28 has a apex 28T which is the outer end in the radial direction y1, and a base end 28B which is located inward in the radial direction y1 from the apex 28T and is connected to the outer surface of the balloon 2. If the projection 28 has an apex 28T, the apex 28T can more easily cut through the stenosis, improving the cutting efficiency of the projection 28. As shown in Figures 3 and 4, in the proximal sleeve section 21, the proximal tapered section 22, the distal tapered section 24, and the distal sleeve section 25, the projection 28 may also have an apex 28T. 【0037】 The protrusion 28 provided on the straight tube section 23 may be tilted in either the first direction d1 or the second direction d2 of the circumferential direction z1. Preferably, the angle at which the protrusion 28 on the straight tube section 23 is tilted in either the first direction d1 or the second direction d2 of the circumferential direction z1 remains within a predetermined range. This allows for efficient fixation of the balloon 2 to the lesion and incision of the stenosis by the protrusion 28. When the protrusion 28 is tilted in either the first direction d1 or the second direction d2 of the circumferential direction z1, it is preferable that the straight line Lp connecting the midpoint of the proximal end 28B in the width direction and the apex 28T is nearly coincidental with the perpendicular Lv of the proximal end 28B, that is, the angle between the straight line Lp connecting the midpoint of the proximal end 28B in the width direction and the apex 28T and the perpendicular Lv of the proximal end 28B is close to 0 degrees. The absolute value of this angle may also be 5 degrees or less, 10 degrees or less, or 15 degrees or less. At this time, the angle between the straight line Lp and the perpendicular Lv of the base end 28B is defined as the angle that the straight line Lp makes with respect to the perpendicular Lv of the base end 28B in the direction in which the projection 28 tilts, with the midpoint of the base end 28B in the width direction as the starting point. Here, the perpendicular Lv is defined as the perpendicular drawn from the apex 28T to the line segment connecting one end and the other end of the base end 28B in the circumferential direction z1 in the cross section in the radial direction y. The midpoint of the base end 28B in the width direction refers to the midpoint of the line segment connecting the end of the projection 28 on the first direction d1 side of the circumferential direction z1 and the end on the second direction d2 side of the circumferential direction z1. 【0038】 As shown in Figure 2, in a cross-section perpendicular to the longitudinal axis x1 of the straight pipe section 23, the region where the protrusion 28 exists has a central section 29a including the top 28T, and ends 29b located on both sides of the central section 29a in the circumferential direction z1. In other words, the region where the protrusion 28 exists has two ends 29b in the circumferential direction z1, with the central section 29a located between the two ends 29b. 【0039】 The central portion 29a is a region that includes the apex 28T. The central portion 29a is a region that includes the apex 28T and may also be a region that includes a straight line Lp connecting the midpoint in the width direction of the base end 28B and the apex 28T. The end portions 29b are regions located on both sides of the central portion 29a in the circumferential direction z1. The end portions 29b are regions located on both sides of the central portion 29a and may include one end of the base end 28B in the circumferential direction z1 and be located on that side of the central portion 29a, and the other end of the base end 28B in the circumferential direction z1 and be located on that side of the central portion 29a. 【0040】 Preferably, the central portion 29a of the protruding portion 28 includes a straight line Lp connecting the midpoint in the width direction of the base end 28B and the apex portion 28T, and is the middle region of the base end 28B divided into three equal parts. Preferably, the end portion 29b of the protruding portion 28 includes one end of the base end 28B in the circumferential direction z1 and is the region located on that one side of the base end 28B divided into three equal parts, and includes the other end of the base end 28B in the circumferential direction z1 and is the region located on the other side of the base end 28B divided into three equal parts. 【0041】 As shown in Figure 2, in a cross section perpendicular to the longitudinal axis x1 in the straight pipe section 23, the thickness Ta of the inner layer 20a in the central section 29a is greater than the thickness Tb of the inner layer 20a in the end section 29b. In the straight pipe section 23, because the thickness Ta of the inner layer 20a in the central section 29a is greater than the thickness Tb of the inner layer 20a in the end section 29b, the inner layer 20a is thicker in the central section 29a than in the end section 29b in the protruding section 28. Since the inner layer 20a is made of a material with a lower Shore D hardness than the outer layer 20b, the cushioning properties of the central section 29a can be enhanced. As a result, when the balloon 2 is expanded and the top 28T of the protruding portion 28 comes into contact with the wall surface of the stenosis, the central portion 29a can easily absorb the resistance force that the top 28T of the protruding portion 28 receives from the wall surface of the stenosis, making it less likely for the position of the top 28T to shift. This improves the safety of treatment and procedures using the balloon catheter 1, while also enabling efficient incision of the stenosis. 【0042】 In a cross-section perpendicular to the longitudinal axis x1 of the straight pipe section 23, the thickness Ta of the inner layer 20a at the central part 29a is preferably 1.2 times or more, more preferably 1.5 times or more, and even more preferably 2 times or more, the thickness Ta of the inner layer 20a at the end part 29b. By setting the lower limit of the ratio between the thickness Ta of the inner layer 20a at the central part 29a and the thickness Tb of the inner layer 20a at the end part 29b of the straight pipe section 23 to the above range, the cushioning effect of the central part 29a is increased, and displacement of the top part 28T is less likely to occur when the stenotic part is incised. Furthermore, in a cross-section perpendicular to the longitudinal axis x1 of the straight pipe section 23, the thickness Ta of the inner layer 20a at the central part 29a is preferably 20 times or less, more preferably 18 times or less, even more preferably 15 times or less, and even more preferably 10 times or less, the thickness Tb of the inner layer 20a at the end part 29b. By setting the upper limit of the ratio between the thickness Ta of the inner layer 20a at the central part 29a of the straight pipe section 23 and the thickness Tb of the inner layer 20a at the end part 29b to the above range, rigidity at the central part 29a can be ensured, and the top part 28T can be made to easily penetrate the constricted section. 【0043】 As shown in Figure 2, in the straight pipe section 23, it is preferable that the balloon 2 has a two-layer structure consisting of at least an inner layer 20a and an outer layer 20b throughout its entire length. That is, in the straight pipe section 23, it is preferable that at least the inner layer 20a and the outer layer 20b are continuously present over the entire 360 ​​degrees in the circumferential direction z1, from the portion of the balloon 2 where the protrusion 28 is not provided to the portion where the protrusion 28 is provided. In the straight pipe section 23, by having a two-layer structure consisting of at least an inner layer 20a and an outer layer 20b throughout its entire length, the scoring function of the protrusion 28, the strength of the balloon 2, and the ease of insertion can be improved by the outer layer 20b, which has a high Shore D hardness. 【0044】 The balloon 2 may have further layers different from the inner layer 20a and the outer layer 20b. For example, although not shown in the figures, the innermost layer may be located inside the inner layer 20a in the radial direction y1, the outermost layer may be located outside the outer layer 20b in the radial direction y1, and an intermediate layer may be located outside the inner layer 20a in the radial direction y1 and inside the outer layer 20b in the radial direction y1. 【0045】 It is preferable that the protruding portion 28 and the balloon body portion 20 are integrally molded. By integrally molding the protruding portion 28 and the balloon body portion 20, it is possible to prevent the protruding portion 28 from falling off the balloon body portion 20. 【0046】 Even when an inner protrusion is provided, it is preferable that the inner layer 20a and outer layer 20b of the balloon 2, in the portion without the inner protrusion and the portion with the inner protrusion, are continuous in the circumferential direction z1. This allows the inner protrusion and the balloon body 20 to be formed integrally, and prevents the inner protrusion from falling off the balloon body 20. 【0047】 As shown in Figure 2, in a cross section perpendicular to the longitudinal axis x1 in the straight pipe section 23, it is preferable that the thickness Ta of the inner layer 20a in the central section 29a is smaller than the thickness Tc of the outer layer 20b in the central section 29a. In the straight pipe section 23, when the thickness Ta of the inner layer 20a in the central section 29a is smaller than the thickness Tc of the outer layer 20b in the central section 29a, the thickness of the outer layer 20b becomes greater than the thickness of the inner layer 20a in the central section 29a, providing cushioning to the central section 29a while increasing the rigidity of the top portion 28T. As a result, the top portion 28T of the protruding portion 28 can be more easily inserted into the constricted section while preventing displacement of the top portion 28T, making it possible to efficiently cut the constricted section. 【0048】 In a cross section perpendicular to the longitudinal axis x1 in the straight pipe section 23, the thickness Ta of the inner layer 20a in the central section 29a is preferably 50% or less, more preferably 45% or less, and even more preferably 40% or less, of the thickness Tc of the outer layer 20b in the central section 29a. By setting the upper limit of the ratio between the thickness Ta of the inner layer 20a and the thickness Tc of the outer layer 20b in the central section 29a within the above range, the rigidity of the central section 29a is increased by the outer layer 20b with high Shore D hardness, making it easier for the top 28T of the protrusion 28 to penetrate the constricted section. Furthermore, in a cross section perpendicular to the longitudinal axis x1 in the straight pipe section 23, the thickness Ta of the inner layer 20a in the central section 29a is preferably 3% or more, more preferably 5% or more, and even more preferably 10% or more, of the thickness Tc of the outer layer 20b in the central section 29a. By setting the lower limit of the ratio between the thickness Ta of the inner layer 20a and the thickness Tc of the outer layer 20b in the central part 29a of the straight pipe section 23 to the above range, the cushioning of the central part 29a can be enhanced by the inner layer 20a with low Shore D hardness, making it easier to absorb the stress on the top 28T of the protruding section 28 and making it possible to create a balloon 2 that is less prone to displacement of the top 28T. 【0049】 As shown in Figure 2, in a cross section perpendicular to the longitudinal axis x1 in the straight pipe section 23, the ratio of the thickness Tc of the outer layer 20b to the thickness Ta of the inner layer 20a at the central section 29a (Tc of the outer layer 20b at the central section 29a / Ta of the inner layer 20a at the central section 29a) is preferably greater than the ratio of the thickness Td of the outer layer 20b to the thickness Tb of the inner layer 20a at the end section 29b (Td of the outer layer 20b at the end section 29b / Tb of the inner layer 20a at the end section 29b). By having a ratio of the thickness Tc of the outer layer 20b to the thickness Ta of the inner layer 20a at the central section 29a greater than the ratio of the thickness Td of the outer layer 20b to the thickness Tb of the inner layer 20a at the end section 29b, it is possible to achieve both cushioning and rigidity in the central section 29a. As a result, displacement of the top 28T of the protruding portion 28 is less likely to occur, and the top 28T can more easily penetrate the narrowed area, making it possible to perform incision of the narrowed area efficiently. 【0050】 In a cross section perpendicular to the longitudinal axis x1 in the straight pipe section 23, the ratio of the thickness Tc of the outer layer 20b to the thickness Ta of the inner layer 20a in the central section 29a is preferably 1.1 times or more, more preferably 1.2 times or more, even more preferably 1.5 times or more, and even more preferably 2 times or more, than the ratio of the thickness Td of the outer layer 20b to the thickness Tb of the inner layer 20a in the end section 29b. By setting the lower limit of the ratio of the ratio of the thickness Tc of the outer layer 20b to the thickness Ta of the inner layer 20a in the central section 29a and the ratio of the thickness Td of the outer layer 20b to the thickness Tb of the inner layer 20a in the end section 29b to the ratio Td of the outer layer 20b to the thickness Tb of the inner layer 20a in the central section 29a to the ratio Td of the outer layer 20b to the thickness Tb of the inner layer 20a in the end section 29b to the ratio of the outer layer 20b to the thickness Tb of the inner layer 20a in the central section 29a to the ratio Td of the outer layer 20b in the end section 29b, the ratio of the outer layer 20b becomes higher in the central section 29a than in the end section 29b. As a result, the rigidity of the central section 29a becomes higher than the rigidity of the end section 29b, and the top 28T of the protruding section 28 becomes more likely to pierce the constricted section. Furthermore, in a cross section perpendicular to the longitudinal axis x1 in the straight pipe section 23, the ratio of the thickness Tc of the outer layer 20b to the thickness Ta of the inner layer 20a in the central section 29a is preferably 10 times or less, more preferably 9 times or less, and even more preferably 8 times or less, the ratio of the thickness Td of the outer layer 20b to the thickness Tb of the inner layer 20a in the end section 29b. By setting the upper limit of the ratio of the ratio of the thickness Tc of the outer layer 20b to the thickness Ta of the inner layer 20a in the central section 29a and the ratio of the thickness Td of the outer layer 20b to the thickness Tb of the inner layer 20a in the end section 29b to the thickness Td, the upper limit of the ratio is set within the above range, it is possible to increase the rigidity of the central section 29a while also providing cushioning, and to create a balloon 2 in which displacement of the top 28T of the protruding section 28 is less likely to occur. 【0051】 In a cross-section perpendicular to the longitudinal axis x1 in at least one of the proximal tapered portion 22 and the distal tapered portion 24, the projection 28 provided on at least one of the proximal tapered portion 22 and the distal tapered portion 24 may be configured not to bend in either the first direction d1 or the second direction d2 of the circumferential direction z1, or it may be configured to be bent in either the first direction d1 or the second direction d2 of the circumferential direction z1. In at least one of the proximal tapered portion 22 and the distal tapered portion 24, the projection 28 does not bend in either the first direction d1 or the second direction d2 of the circumferential direction z1, and the rigidity of the balloon 2 in the longitudinal axis x1 is increased by the projection 28 in the proximal tapered portion 22 and the distal tapered portion 24 where the projection 28 is provided. As a result, the ease of inserting the balloon 2 into the vascular lumen can be improved. In at least one of the proximal tapered portion 22 and the distal tapered portion 24, the projection 28 is tilted in either the first direction d1 or the second direction d2 in the circumferential direction z1. This makes it less likely for the top 28T of the projection 28 of the proximal tapered portion 22 or the distal tapered portion 24 to come into contact with other objects such as the vascular lumen wall when delivering the balloon 2 to the lesion, thereby preventing damage to the vascular lumen wall. 【0052】 In a cross-section perpendicular to the longitudinal axis x1 in at least one of the proximal tapered portion 22 and the distal tapered portion 24, the central portion 29a is preferably a region that includes the apex portion 28T. Alternatively, the central portion 29a may be a region that includes a straight line Lp connecting the midpoint in the width direction of the base end 28B and the apex portion 28T in a cross-section perpendicular to the longitudinal axis x1 in at least one of the proximal tapered portion 22 and the distal tapered portion 24. In the case where the protruding portion 28 is tilted in either the first direction d1 or the second direction d2 of the circumferential direction z1 in at least one of the proximal tapered portion 22 and the distal tapered portion 24, the central portion 29a is preferably a region that includes a straight line Lp connecting the midpoint in the width direction of the base end 28B and the apex portion 28T in a cross-section perpendicular to the longitudinal axis x1 in at least one of the proximal tapered portion 22 and the distal tapered portion 24. 【0053】 Although not shown in the figures, in a cross-section perpendicular to the longitudinal axis x1 in at least one of the proximal tapered portion 22 and the distal tapered portion 24, the tip portion of the protruding portion 28 provided on at least one of the proximal tapered portion 22 and the distal tapered portion 24 may be removed by processing such as cutting, melting, or crushing, so as to be on the outer side of the radial direction y1. By removing the tip portion of the protruding portion 28 provided on at least one of the proximal tapered portion 22 and the distal tapered portion 24, when the balloon 2 is inserted into the lumen of a blood vessel, it is possible to make the lumen of the blood vessel less likely to be damaged even if the protruding portion 28 of the proximal tapered portion 22 or the distal tapered portion 24 of the balloon 2 comes into contact with the lumen of the blood vessel, thus making the balloon 2 safer. 【0054】 If the tip portion on the outer side of the radial direction y1 is removed from the protruding portion 28 provided on at least one of the protruding portion 22 and the distal portion 24, the central portion 29a of the protruding portion 28 may have an inner layer 20a and no outer layer 20b. In other words, the outer layer 20b may not be present in the central portion 29a of the protruding portion 28 in at least one of the protruding portion 22 and the distal portion 24. 【0055】 If the position of the apex 28T is difficult to determine due to the deformation or removal of the tip portion on the outer side of the radial direction y1 of the protruding portion 28 provided on at least one of the protruding portion 22 and the distal tapered portion 24, the central portion 29a may be defined as the region in a cross section perpendicular to the longitudinal axis x1 that includes a straight line passing through the midpoint in the width direction of the base end 28B and the centroid of the outer shape of the balloon 2. 【0056】 As shown in Figure 3, in a cross section perpendicular to the longitudinal axis x1 in at least one of the proximal tapered portion 22 and the distal tapered portion 24, it is preferable that the thickness Ta of the inner layer 20a at the central portion 29a is greater than the thickness Tb of the inner layer at the end portion 29b. By having the thickness Ta of the inner layer 20a at the central portion 29a greater than the thickness Tb of the inner layer at the end portion 29b in at least one of the proximal tapered portion 22 and the distal tapered portion 24, the flexibility of the central portion 29a in the proximal tapered portion 22 and the distal tapered portion 24 can be increased. As a result, when inserting the balloon 2 into the vascular lumen, even if the top portion 28T of the protruding portion 28 of the proximal tapered portion 22 or the distal tapered portion 24 comes into contact with the vascular lumen wall, it is less likely to cause damage, thereby improving the safety of the balloon 2. 【0057】 In a cross-section perpendicular to the longitudinal axis x1 in at least one of the proximal tapered portion 22 and the distal tapered portion 24, the thickness Ta of the inner layer 20a in the central portion 29a is preferably 1.1 times or more, more preferably 1.2 times or more, and even more preferably 1.3 times or more, the thickness Tb of the inner layer 20a in the end portion 29b. By setting the lower limit of the ratio between the thickness Ta of the inner layer 20a in the central portion 29a and the thickness Tb of the inner layer 20a in the end portion 29b in at least one of the proximal tapered portion 22 and the distal tapered portion 24 to the above range, the central portion 29a of the proximal tapered portion 22 and the distal tapered portion 24 becomes flexible, and even if the top portion 28T of the protruding portion 28 of the proximal tapered portion 22 and the distal tapered portion 24 comes into contact with the vascular lumen wall, it becomes less likely to damage the vascular lumen wall. Furthermore, in a cross-section perpendicular to the longitudinal axis x1 in at least one of the proximal tapered portion 22 and the distal tapered portion 24, the thickness Ta of the inner layer 20a in the central portion 29a is preferably 20 times or less, more preferably 10 times or less, and even more preferably 5 times or less, the thickness Tb of the inner layer 20a in the end portion 29b. By setting the upper limit of the ratio between the thickness Ta of the inner layer 20a in the central portion 29a and the thickness Tb of the inner layer 20a in the end portion 29b in at least one of the proximal tapered portion 22 and the distal tapered portion 24 to the above range, it is possible to impart appropriate rigidity to the central portion 29a, thereby increasing the strength of the balloon 2 and improving the ease of insertion into the vascular lumen and the efficiency of incision of stenotic portions. 【0058】 It is preferable that the thickness Ta of the inner layer 20a at the central portion 29a in a cross section perpendicular to the longitudinal axis x1 in at least one of the proximal tapered portion 22 and the distal tapered portion 24 is greater than the thickness Ta of the inner layer 20a at the central portion 29a in a cross section perpendicular to the longitudinal axis x1 in the straight pipe portion 23. In other words, it is preferable that the thickness Ta of the inner layer 20a at the central portion 29a is thicker in at least one of the proximal tapered portion 22 and the distal tapered portion 24 than in the straight pipe portion 23. Because the thickness Ta of the inner layer 20a at the central portion 29a in at least one of the proximal tapered portion 22 and the distal tapered portion 24 is greater than the thickness Ta of the inner layer 20a at the central portion 29a in the straight pipe portion 23, the central portion 29a is more flexible in the proximal tapered portion 22 and the distal tapered portion 24 than in the straight pipe portion 23. As a result, the straight section 23 facilitates the incision of the stenosis by the protruding section 28, and the protruding section 22 and distal section 24 make it less likely for the protruding section 28 to injure the vascular lumen wall even if it comes into contact with the vascular lumen wall while being inserted through the vascular lumen. Therefore, it is possible to create a balloon 2 that is highly efficient at incising the stenosis and is also highly safe. 【0059】 The thickness Ta of the inner layer 20a at the central portion 29a in a cross section perpendicular to the longitudinal axis x1 in at least one of the proximal tapered portion 22 and the distal tapered portion 24 is preferably 1.1 times or more, more preferably 1.2 times or more, and even more preferably 1.3 times or more, the thickness Ta of the inner layer 20a at the central portion 29a in a cross section perpendicular to the longitudinal axis x1 in the straight pipe portion 23. By setting the lower limit of the ratio between the thickness Ta of the inner layer 20a in the central portion 29a of at least one of the proximal tapered portion 22 and the distal tapered portion 24 and the thickness Ta of the inner layer 20a in the central portion 29a of the straight tube portion 23 to the above range, the flexibility of the central portion 29a of the proximal tapered portion 22 and the distal tapered portion 24 can be increased compared to the central portion 29a of the straight tube portion 23, and the effect of making it less likely to damage the vascular lumen wall even if the top 28T of the protruding portion 28 of the proximal tapered portion 22 and the distal tapered portion 24 comes into contact with it can be enhanced. Furthermore, the thickness Ta of the inner layer 20a at the central portion 29a in a cross section perpendicular to the longitudinal axis x1 in at least one of the proximal tapered portion 22 and the distal tapered portion 24 is preferably 5 times or less, more preferably 3 times or less, and even more preferably 2 times or less, the thickness Ta of the inner layer 20a at the central portion 29a in a cross section perpendicular to the longitudinal axis x1 in the straight tube portion 23. By setting the upper limit of the ratio of the thickness Ta of the inner layer 20a at the central portion 29a in at least one of the proximal tapered portion 22 and the distal tapered portion 24 to the thickness Ta of the inner layer 20a at the central portion 29a in the straight tube portion 23 to the above range, the rigidity of the balloon 2 in the proximal tapered portion 22 and the distal tapered portion 24 can be maintained, the strength of the balloon 2 can be increased, and the ease of insertion into the vascular lumen can be improved. 【0060】 In a cross-section perpendicular to the longitudinal axis x1 in at least one of the proximal sleeve portion 21 and the distal sleeve portion 25, the projection 28 provided on at least one of the proximal sleeve portion 21 and the distal sleeve portion 25 may be configured not to be tilted in either the first direction d1 or the second direction d2 of the circumferential direction z1, or it may be configured to be tilted in either the first direction d1 or the second direction d2 of the circumferential direction z1. In at least one of the proximal sleeve portion 21 and the distal sleeve portion 25, the projection 28 is not tilted in either the first direction d1 or the second direction d2 of the circumferential direction z1, thereby increasing the rigidity of the balloon 2 in the longitudinal axis x1 in the proximal sleeve portion 21 and the distal sleeve portion 25 where the projection 28 is provided, and improving the ease of inserting the balloon 2 into the vascular lumen. In at least one of the proximal sleeve portion 21 and the distal sleeve portion 25, the projection 28 is tilted in either the first direction d1 or the second direction d2 of the circumferential direction z1. This makes it less likely for the top 28T of the projection 28 on the proximal sleeve portion 21 or the distal sleeve portion 25 to come into contact with the vascular lumen wall when the balloon 2 is delivered to the lesion. Therefore, it is possible to prevent damage to the vascular lumen wall by the projection 28 of the proximal sleeve portion 21 or the distal sleeve portion 25. 【0061】 In a cross-section perpendicular to the longitudinal axis x1 in at least one of the proximal sleeve portion 21 and the distal sleeve portion 25, the central portion 29a is preferably a region that includes the apex portion 28T. Alternatively, the central portion 29a may be a region that includes a straight line Lp connecting the midpoint in the width direction of the base end 28B and the apex portion 28T in a cross-section perpendicular to the longitudinal axis x1 in at least one of the proximal sleeve portion 21 and the distal sleeve portion 25. If the protrusion 28 is tilted in either the first direction d1 or the second direction d2 of the circumferential direction z1 in at least one of the proximal sleeve portion 21 and the distal sleeve portion 25, the central portion 29a is preferably a region that includes a straight line Lp connecting the midpoint in the width direction of the base end 28B and the apex portion 28T in a cross-section perpendicular to the longitudinal axis x1 in at least one of the proximal sleeve portion 21 and the distal sleeve portion 25. 【0062】 Although not shown in the figures, in a cross-section perpendicular to the longitudinal axis x1 in at least one of the proximal sleeve portion 21 and the distal sleeve portion 25, the tip portion of the protrusion 28 provided on at least one of the proximal sleeve portion 21 and the distal sleeve portion 25 may be removed by processing such as cutting, melting, or crushing, so as to be on the outer side of the radial direction y1. By removing the tip portion of the protrusion 28 provided on at least one of the proximal sleeve portion 21 and the distal sleeve portion 25, when inserting the balloon 2 into the lumen of a blood vessel, even if the protrusion 28 provided on the proximal sleeve portion 21 or the distal sleeve portion 25 comes into contact with other objects such as the lumen wall of the blood vessel, it is less likely to damage the lumen wall of the blood vessel, etc. Therefore, it is possible to make a balloon 2 that is less likely to damage the lumen wall of the blood vessel, etc. and is safer. 【0063】 If the tip portion on the outer side of the radial direction y1 is removed from the protruding portion 28 provided on at least one of the proximal sleeve portion 21 and the distal sleeve portion 25, the central portion 29a of the protruding portion 28 may have an inner layer 20a and no outer layer 20b in at least one of the proximal sleeve portion 21 and the distal sleeve portion 25 from which the tip portion of the protruding portion 28 has been removed. In other words, the central portion 29a of the protruding portion 28 may not have an outer layer 20b in at least one of the proximal sleeve portion 21 and the distal sleeve portion 25. 【0064】 If the position of the apex 28T is difficult to determine due to the deformation or removal of the tip portion on the outer side of the radial direction y1 of the protruding portion 28 provided on at least one of the protruding portion 21 and the distal portion 25, the central portion 29a may be defined as the region in a cross section perpendicular to the longitudinal axis x1 that includes a straight line connecting the midpoint in the width direction of the base end 28B and the centroid of the outer shape of the balloon 2. 【0065】 As shown in Figure 4, in a cross-section perpendicular to the longitudinal axis x1 in at least one of the proximal sleeve portion 21 and the distal sleeve portion 25, it is preferable that the thickness Ta of the inner layer 20a in the central portion 29a is greater than the thickness Tb of the inner layer at the end portion 29b. By making the thickness Ta of the inner layer 20a in the central portion 29a greater than the thickness Tb of the inner layer at the end portion 29b in at least one of the proximal sleeve portion 21 and the distal sleeve portion 25, the central portion 29a of the proximal sleeve portion 21 and the distal sleeve portion 25 can be made flexible. Therefore, when inserting the balloon 2 into the lumen of a blood vessel, even if the top portion 28T of the protrusion 28 provided on the proximal sleeve portion 21 and the distal sleeve portion 25 comes into contact with the lumen wall of the blood vessel, the lumen wall is less likely to be damaged, resulting in a safer balloon 2. 【0066】 In a cross-section perpendicular to the longitudinal axis x1 in at least one of the proximal sleeve portion 21 and the distal sleeve portion 25, the thickness Ta of the inner layer 20a in the central portion 29a is preferably 1.1 times or more, more preferably 1.2 times or more, and even more preferably 1.3 times or more, the thickness Tb of the inner layer 20a in the end portion 29b. By setting the lower limit of the ratio between the thickness Ta of the inner layer 20a in the central portion 29a and the thickness Tb of the inner layer 20a in the end portion 29b in at least one of the proximal sleeve portion 21 and the distal sleeve portion 25 to the above range, the flexibility of the central portion 29a of the proximal sleeve portion 21 and the distal sleeve portion 25 can be increased, and the top portion 28T of the protruding portion 28 of the proximal sleeve portion 21 and the distal sleeve portion 25 can be less likely to cause damage even if they come into contact with the vascular lumen wall. Furthermore, in a cross-section perpendicular to the longitudinal axis x1 in at least one of the proximal sleeve portion 21 and the distal sleeve portion 25, the thickness Ta of the inner layer 20a in the central portion 29a is preferably 20 times or less, more preferably 10 times or less, and even more preferably 8 times or less, the thickness Tb of the inner layer 20a in the end portion 29b. By setting the upper limit of the ratio between the thickness Ta of the inner layer 20a in the central portion 29a and the thickness Tb of the inner layer 20a in the end portion 29b in at least one of the proximal sleeve portion 21 and the distal sleeve portion 25 to the above range, the central portion 29a will have appropriate rigidity. As a result, the strength of the balloon 2 can be increased, improving the insertability of the balloon 2 in the vascular lumen and making it possible to create a balloon 2 with good efficiency in cutting the stenotic portion. 【0067】 It is preferable that the thickness Ta of the inner layer 20a at the central portion 29a in a cross section perpendicular to the longitudinal axis x1 in at least one of the proximal sleeve portion 21 and the distal sleeve portion 25 is greater than the thickness Ta of the inner layer 20a at the central portion 29a in a cross section perpendicular to the longitudinal axis x1 in the straight pipe portion 23. In other words, it is preferable that the thickness Ta of the inner layer 20a at the central portion 29a is thicker in at least one of the proximal sleeve portion 21 and the distal sleeve portion 25 than in the straight pipe portion 23. Because the thickness Ta of the inner layer 20a at the central portion 29a in at least one of the proximal sleeve portion 21 and the distal sleeve portion 25 is greater than the thickness Ta of the inner layer 20a at the central portion 29a in the straight pipe portion 23, the central portion 29a of the proximal sleeve portion 21 and the distal sleeve portion 25 is more flexible than that of the straight pipe portion 23. Therefore, in the straight tube section 23, the protruding portion 28 makes it easier to incise the stenotic portion, and in the proximal sleeve section 21 and distal sleeve section 25, the protruding portion 28 is less likely to cause injury even if it comes into contact with the vascular lumen wall. As a result, both the efficiency and safety of incising the stenotic portion of the balloon 2 can be improved. 【0068】 The thickness Ta of the inner layer 20a at the central portion 29a in a cross section perpendicular to the longitudinal axis x1 in at least one of the proximal sleeve portion 21 and distal sleeve portion 25 is preferably 1.1 times or more, more preferably 1.2 times or more, and even more preferably 1.3 times or more, the thickness Ta of the inner layer 20a at the central portion 29a in a cross section perpendicular to the longitudinal axis x1 in the straight pipe portion 23. By setting the lower limit of the ratio of the thickness Ta of the inner layer 20a at the central portion 29a in at least one of the proximal sleeve portion 21 and distal sleeve portion 25 to the thickness Ta of the inner layer 20a at the central portion 29a in the straight pipe portion 23 within the above range, the flexibility of the central portion 29a of the proximal sleeve portion 21 and distal sleeve portion 25 can be increased compared to the straight pipe portion 23. Therefore, even if the top 28T of the protruding portion 28 of the protruding portion 21 or the distal sleeve portion 25 comes into contact with the vascular lumen wall, it becomes possible to make it less likely to damage the vascular lumen wall. Furthermore, the thickness Ta of the inner layer 20a at the central portion 29a in a cross section perpendicular to the longitudinal axis x1 in at least one of the proximal sleeve portion 21 and the distal sleeve portion 25 is preferably 5 times or less, more preferably 3 times or less, and even more preferably 2 times or less, the thickness Ta of the inner layer 20a at the central portion 29a in a cross section perpendicular to the longitudinal axis x1 in the straight tube portion 23. By setting the upper limit of the ratio between the thickness Ta of the inner layer 20a in the central portion 29a of at least one of the proximal sleeve portion 21 and the distal sleeve portion 25 and the thickness Ta of the inner layer 20a in the central portion 29a of the straight tube portion 23 to the above range, it becomes possible to increase the rigidity of the balloon 2 in the proximal sleeve portion 21 and the distal sleeve portion 25, improve the strength of the balloon 2, and create a balloon 2 that is easily inserted into the vascular lumen. 【0069】 2. Balloon catheter A balloon catheter 1 according to an embodiment of the present invention comprises the balloon catheter balloon 2 described above. As described in section 1, "Balloon for balloon catheter", as shown in Figure 1, the balloon 2 is connected to the distal end of the shaft 30. 【0070】 Figure 1 shows a so-called rapid exchange type balloon catheter 1, which has a guidewire port 50 located midway from the distal to the proximal end of the shaft 30, and an inner shaft 60 that functions as a guidewire insertion passage from the guidewire port 50 to the distal end of the shaft 30. Preferably, the balloon catheter 1 has a distal shaft 31 and a proximal shaft 32, and the distal shaft 31 and the proximal shaft 32 are separate components, and the proximal end of the distal shaft 31 is connected to the distal end of the proximal shaft 32, thereby forming a shaft 30 that extends from the balloon 2 to the proximal end of the balloon catheter 1. Alternatively, one shaft 30 may extend from the balloon 2 to the proximal end of the balloon catheter 1, and the distal shaft 31 and the proximal shaft 32 may be composed of multiple tubular members. 【0071】 It is preferable that the shaft 30 has a fluid channel and a guide wire insertion passage inside. To configure the shaft 30 to have a fluid channel and a guide wire insertion passage inside, for example, an inner shaft 60 located inside the shaft 30 can function as a guide wire insertion passage, and the space between the shaft 30 and the inner shaft 60 can function as a fluid channel. In such a configuration, it is preferable that the inner shaft 60 extends from the distal end of the shaft 30 and penetrates the balloon 2, with the distal side of the balloon 2 connected to the inner shaft 60 and the proximal side of the balloon 2 connected to the shaft 30. 【0072】 The shaft 30 is preferably composed of resin, metal, or a combination of resin and metal. Using resin as a constituent material for the shaft makes it easier to impart flexibility and elasticity to the shaft 30. Using metal as a constituent material for the shaft 30 can improve the delivery of the balloon catheter 1. Examples of resins that make up the shaft 30 include polyamide resins, polyester resins, polyurethane resins, polyolefin resins, fluororesins, vinyl chloride resins, silicone resins, natural rubber, and synthetic rubber. These may be used individually or in combination of two or more. Examples of metals that make up the shaft 30 include stainless steel such as SUS304 and SUS316, platinum, nickel, cobalt, chromium, titanium, tungsten, gold, Ni-Ti alloy, Co-Cr alloy, or combinations thereof. When the shaft 30 is composed of a distal shaft 31 and a proximal shaft 32, which are separate components, for example, the distal shaft 31 can be formed from resin and the proximal shaft 32 can be formed from metal. Furthermore, the shaft 30 may have a laminated structure made of different or the same material. 【0073】 The balloon 2 and shaft 30 can be joined by adhesive bonding, welding, or by attaching a ring-shaped member to the overlapping portion of the balloon 2 and shaft 30 and crimping it. Among these, it is preferable that the balloon 2 and shaft 30 are joined by welding. By welding the balloon 2 and shaft 30, the joint between the balloon 2 and shaft 30 is less likely to come undone even when the balloon 2 is repeatedly expanded or contracted, thereby improving the joint strength. 【0074】 Preferably, a tip member 70 is provided at the distal end of the balloon catheter 1. The tip member 70 may be provided at the distal end of the balloon catheter 1 by being connected to the distal end of the balloon 2 as a separate component from the inner shaft 60, or the inner shaft 60, which extends distal to the distal end of the balloon 2, may function as the tip member 70. 【0075】 On the inner shaft 60 inside the balloon 2, radiopaque markers 80 may be placed at the location of the balloon 2 in the longitudinal axis direction x1 so that the position of the balloon 2 can be confirmed by X-ray fluoroscopy. Preferably, the radiopaque markers 80 are placed at positions corresponding to both ends of the straight tube portion 23 of the balloon 2, or they may be placed at a position corresponding to the center of the straight tube portion 23 in the longitudinal axis direction x1. 【0076】 A hub 5 may be provided on the proximal side of the shaft 30, 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 2. 【0077】 The shaft 30 and the hub 5 can be joined by, for example, adhesive bonding or welding. In particular, it is preferable that the shaft 30 and the hub 5 are joined by adhesive bonding. By bonding the shaft 30 and the hub 5, the bonding strength between the shaft 30 and the hub 5 can be increased, improving the durability of the balloon catheter 1, especially when the materials constituting the shaft 30 and the hub 5 are different, for example, when the shaft 30 is made of a highly flexible material and the hub 5 is made of a highly rigid material. 【0078】 Although not shown in the figures, the present invention can also be applied to so-called over-the-wire type balloon catheters, which have a guidewire insertion passage extending from the distal to the proximal end of the shaft. In the case of the over-the-wire type, 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. 【0079】 In the case of a rapid exchange type catheter, it is preferable that the outer walls of the distal shaft 31 and / or the proximal shaft 32 are appropriately coated, and it is more preferable that both the distal shaft 31 and the proximal shaft 32 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. 【0080】 The coating can be hydrophilic or hydrophobic depending on the purpose, and can be applied by immersing the shaft 30 in a hydrophilic or hydrophobic coating agent, applying a hydrophilic or hydrophobic coating agent to the outer wall of the shaft 30, or covering the outer wall of the shaft 30 with a hydrophilic or hydrophobic coating agent. The coating agent may contain chemicals or additives. 【0081】 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. 【0082】 Examples of hydrophobic coating agents include polytetrafluoroethylene (PTFE), ethylene fluoride 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. 【0083】 3. Method for manufacturing a balloon catheter A method for manufacturing a balloon catheter according to an embodiment of the present invention is a method for manufacturing the balloon catheter described above, comprising the steps of: preparing a parison having radial, circumferential, and longitudinal axis directions and a lumen extending in the longitudinal axis direction; and biaxially stretching the parison to manufacture a balloon having a proximal sleeve portion, a proximal tapered portion, a straight tube portion, a distal tapered portion, and a distal sleeve portion, and a protruding portion that protrudes radially outward and extends in the longitudinal axis direction, wherein the parison has an outer layer and an inner layer made of a material with a lower Shore D hardness than the outer layer, and has a protruding region including a protruding portion that protrudes radially outward and extends in the longitudinal axis direction, and a non-protruding region other than the protruding region, and in a cross section perpendicular to the longitudinal axis direction, the inner layer has a small thickness portion in the non-protruding region and a large thickness portion in the protruding region that is thicker than the thickness of the small thickness portion. 【0084】 In the method according to the embodiment of the present invention, the parison has an outer layer and an inner layer made of a material with a lower Shore D hardness than the outer layer, and has a protruding region and a non-protruding region, and in a cross section perpendicular to the longitudinal axis, the inner layer has a thin portion in the non-protruding region and a thick portion in the protruding region. By manufacturing a balloon by biaxial stretching such a parison, it is possible to manufacture a "2. balloon catheter" which has a "1. balloon for balloon catheter" in which the thickness of the inner layer in the central part including the top of the protruding portion is greater than the thickness of the inner layer at the ends located on both sides in the circumferential direction of the central part. 【0085】 A method for manufacturing a balloon catheter according to an embodiment of the present invention will be described with reference to Figures 5 to 9. Figure 5 shows a perspective view of a parison before biaxial stretching according to one embodiment of the present invention. Figure 6 shows a cross-sectional view of the parison shown in Figure 5 from VI to VI, and Figure 7 shows a cross-sectional view perpendicular to the longitudinal axis of the parison mold used in the manufacture of the parison shown in Figure 6. Figure 8 shows a cross-sectional view in the longitudinal axis direction of the mold used for biaxial stretching of the parison in the manufacturing method according to an embodiment of the present invention. Figure 9 shows a cross-sectional view of the mold shown in Figure 8 from IX to IX. 【0086】 First, prepare the parison 200. As shown in Figure 5, the parison 200 is a cylindrical member made of resin and has a lumen 205. The parison 200 has a first end 201 and a second end 202, and extends in the longitudinal axis direction x2 from the first end 201 to the second end 202. The parison 200 has a radial direction y2 and a circumferential direction z2, similar to the balloon 2. 【0087】 As shown in Figure 6, the parison 200 has an outer layer 200b and an inner layer 200a made of a material with a lower Shore D hardness than the outer layer 200b. For information on the materials constituting the inner layer 200a and the outer layer 200b, and their Shore D hardness, please refer to the description of the resins constituting the inner layer 20a and the outer layer 20b, and the description of their Shore D hardness, in section "1. Balloons for Balloon Catheters". 【0088】 The parison 200 has a protruding region R1 including a protruding portion 208 that protrudes outward in the radial direction y2 and extends in the longitudinal direction x2, and a non-protruding region R2 other than the protruding region R1. By biaxial stretching the parison 200, the protruding portion 208 can be formed into the protruding portion 28 of the balloon 2, and the non-protruding region R2 can be formed into the balloon body portion 20 other than the protruding portion 28. 【0089】 As shown in Figure 6, there may be multiple protrusions 208 in the circumferential direction z2, or, although not shown, there may be one protrusion 208 in the circumferential direction z2. When there are multiple protrusions 208 in the circumferential direction z2, it is preferable that the multiple protrusions 208 are spaced apart in the circumferential direction z2, and more preferably that they are arranged at equal intervals in the circumferential direction z2. 【0090】 As shown in Figure 6, in a cross section perpendicular to the longitudinal axis x2, the inner layer 200a has a small thickness portion 220 in the non-protruding region R2 and a large thickness portion 210 in the protruding region R1 that is thicker than the small thickness portion 220. Because the inner layer 200a has a large thickness portion 210 in the protruding region R1, it is possible to manufacture a balloon 2 in which the thickness Ta of the inner layer 20a in the central portion 29a including the top portion 28T of the protruding portion 28 is greater than the thickness Tb of the inner layer 20a in the ends 29b located on both sides of the central portion 29a. 【0091】 Such a parison 200 can be manufactured, for example, by extruding resin using a parison mold 250 as shown in Figure 7. As shown in Figure 7, the parison mold 250 preferably has a first cylindrical member 251, a second cylindrical member 252, and a third cylindrical member 253, wherein the first cylindrical member 251 has a cylindrical shape so as to form the inner cavity 205 of the parison 200, the second cylindrical member 252 has a cylindrical shape with protrusions so as to form a large thickness portion 210 and a small thickness portion 220 of the inner layer 200a, and the third cylindrical member 253 preferably has a cylindrical shape with protrusions so as to form a protrusion 208. As a result, by introducing a resin to form the inner layer 200a in the space between the outer surface of the first cylindrical member 251 and the inner surface of the second cylindrical member 252, and introducing a resin to form the outer layer 200b in the space between the outer surface of the second cylindrical member 252 and the inner surface of the third cylindrical member 253, and then extruding the resin, a parison 200 having a protrusion 208, an inner layer 200a, and an outer layer 200b, and having a thicker portion 210 in the protrusion region R1 of the inner layer 200a, can be manufactured. 【0092】 The material constituting the parison mold 250 is preferably metal, more preferably iron, copper, aluminum, or an alloy thereof. For example, stainless steel is an example of an iron alloy, brass is an example of a copper alloy, and duralumin is an example of an aluminum alloy. From the standpoint of having sufficient conductivity and strength, as well as ease of processing, the parison mold 250 is preferably made of stainless steel. 【0093】 By biaxially stretching the parison 200, a balloon 2 is manufactured having a proximal sleeve portion 21, a proximal tapered portion 22, a straight tube portion 23, a distal tapered portion 24, and a distal sleeve portion 25, and a protruding portion 28. In this case, a mold 300 as shown in Figure 8 can be used. The mold 300 has a longitudinal axis direction x3, a radial direction y3, and a circumferential direction z3, and has a lumen 305 that extends in the longitudinal axis direction x3 into which the parison 200 is inserted. Preferably, a portion of the parison 200 in the longitudinal axis direction x2 is positioned in the lumen 305 of the mold 300. 【0094】 Preferably, the mold 300 has a mold straight pipe section 300C that forms the straight pipe section of the balloon 2 in the longitudinal axis direction x3, two mold tapered sections 300T that are arranged on both sides of the mold straight pipe section 300C and form the tapered section of the balloon 2, and two mold sleeve sections 300S that are arranged further away from the mold straight pipe section 300C than the mold tapered sections 300T and form the sleeve section of the balloon 2. This allows the mold straight pipe section 300C to form the straight pipe section 23 of the balloon 2, the mold tapered sections 300T to form the proximal tapered section 22 and the distal tapered section 24, and the mold sleeve sections 300S to form the proximal sleeve section 21 and the distal sleeve section 25. 【0095】 The mold 300 may be composed of one component or multiple components. As shown in Figure 8, it may be composed of multiple mold components connected to each other in the longitudinal axis direction x3. For example, the mold straight section 300C, the mold tapered section 300T, and the mold sleeve section 300S may each be different mold components, and these may be connected to each other in the longitudinal axis direction x3. The mold 300 may also be separable in the radial direction y. This makes it easier to insert the parison 200 into the lumen 305 of the mold 300. As shown in Figure 8, each mold component may be joined by engaging adjacent mold components with each other, or, although not shown, adjacent mold components may be joined by magnetic attraction by attaching magnets to each of them. 【0096】 As shown in Figure 9, it is preferable that the lumen 305 of the mold 300 is formed from a groove 310 that is recessed outward in the radial direction y3 and extends in the longitudinal axis direction x3, and a cylindrical wall portion 320 other than the groove 310. This allows the protrusion 208 of the parison 200 to be inserted into the groove 310 to form the protrusion 28 of the balloon 2. Multiple grooves 310 may be provided in the circumferential direction z3, or, although not shown, one groove 310 may be provided in the circumferential direction z3. If multiple grooves 310 are provided in the circumferential direction z3, it is preferable that the grooves 310 are spaced apart in the circumferential direction z3, and more preferably that they are arranged at equal intervals in the circumferential direction z3. 【0097】 The groove 310 is preferably provided in the straight pipe section 300C of the mold, but may also be provided in the tapered section 300T of the mold or the sleeve section 300S of the mold. By providing the groove 310 in the straight pipe section 300C of the mold, a protrusion 28 can be formed on the straight pipe section 23 of the balloon 2, thereby improving the efficiency of cutting the narrowed portion by the balloon 2. The depth of the groove 310 provided in the tapered section 300T of the mold or the sleeve section 300S may be shallower or equal to the depth of the groove 310 provided in the straight pipe section 300C of the mold. 【0098】 The material constituting the mold 300 is preferably metal, more preferably iron, copper, aluminum, or an alloy thereof. For example, stainless steel is an example of an iron alloy, brass is an example of a copper alloy, and duralumin is an example of an aluminum alloy. From the standpoint of having sufficient conductivity and strength, as well as ease of processing, the parison mold 300 is preferably made of stainless steel. [Explanation of symbols] 【0099】 1: Balloon catheter 2: Balloon for balloon catheter 5: Hub 6:Fluid injection part 20: Balloon body 20a: Inner layer 20b: Outer layer 21: Proximal sleeve portion 22: Proximal tapered section 23: Straight pipe section 24: Distal tapered section 25: Distal sleeve portion 28:Protrusion 28T:Top 28B: Proximal end 29a: Central part 29b: End 30: Shaft 31: Distal shaft 32: Proximal shaft 50: Guide wire port 60: Inner shaft 70: Tip component 80: Marker 200: Parison 200a: Inner layer of parison 200b: Outer layer of the parison 201: Parison's First End 202: Parison's second end 205: Parison's lumen 208: Parison projection 210: Daikobu 220: Koatsube 250: Mold for parison 251: First cylindrical member 252: Second cylindrical member 253: Third cylindrical member 300: Mold 300C: Straight pipe section of mold 300S: Mold sleeve section 300T: Mold tapered section 305: Inner cavity of the mold 310: Groove 320: Cylindrical wall Lp: A straight line connecting the midpoint of the base in the width direction and the apex. Lv: Perpendicular to the base Ta: Thickness of the inner layer in the central part Tb: Thickness of the inner layer at the end Tc: Thickness of the outer layer in the central part Td: Thickness of the outer layer at the edge

Claims

[Claim 1] A balloon for a balloon catheter having longitudinal, radial, and circumferential directions, and comprising an outer layer and an inner layer made of a material with a lower Shore D hardness than the outer layer, It has a straight pipe section, a proximal tapered section located proximal to the straight pipe section, a proximal sleeve section located proximal to the proximal tapered section, a distal tapered section located distal to the straight pipe section, and a distal sleeve section located distal to the distal tapered section. It has a projection that protrudes radially outward and extends in the longitudinal direction, In the cross-section perpendicular to the longitudinal axis of the straight pipe section, the region where the protrusion exists has a central portion including the top of the protrusion, and ends located on both sides of the central portion in the circumferential direction. A balloon catheter balloon in which, in a cross-section perpendicular to the longitudinal axis in the straight tube portion, the thickness of the inner layer in the central portion is greater than the thickness of the inner layer at the end portion. [Claim 2] The balloon for a balloon catheter according to claim 1, wherein in a cross section perpendicular to the longitudinal axis direction in the straight tube portion, the thickness of the inner layer in the central portion is smaller than the thickness of the outer layer in the central portion. [Claim 3] A balloon for a balloon catheter according to claim 1 or 2, wherein in a cross section perpendicular to the longitudinal axis direction in the straight tube portion, the ratio of the thickness of the outer layer to the thickness of the inner layer in the central portion (thickness of the outer layer in the central portion / thickness of the inner layer in the central portion) is greater than the ratio of the thickness of the outer layer to the thickness of the inner layer at the end portion (thickness of the outer layer at the end portion / thickness of the inner layer at the end portion). [Claim 4] The balloon for a balloon catheter according to claim 1 or 2, wherein in a cross section perpendicular to the longitudinal axis in at least one of the proximal tapered portion and the distal tapered portion, the thickness of the inner layer in the central portion is greater than the thickness of the inner layer at the end portion. [Claim 5] The balloon for a balloon catheter according to claim 4, wherein the thickness of the inner layer at the central portion of a cross section perpendicular to the longitudinal axis in at least one of the proximal tapered portion and the distal tapered portion is greater than the thickness of the inner layer at the central portion of a cross section perpendicular to the longitudinal axis in the straight tube portion. [Claim 6] The balloon for a balloon catheter according to claim 1 or 2, wherein in a cross section perpendicular to the longitudinal axis in at least one of the proximal sleeve portion and the distal sleeve portion, the thickness of the inner layer in the central portion is greater than the thickness of the inner layer at the end portion. [Claim 7] The balloon for a balloon catheter according to claim 6, wherein the thickness of the inner layer in the central part of a cross section perpendicular to the longitudinal axis in at least one of the proximal sleeve portion and the distal sleeve portion is greater than the thickness of the inner layer in the central part of a cross section perpendicular to the longitudinal axis in the straight tube portion. [Claim 8] A balloon catheter comprising a balloon for a balloon catheter as described in claim 1 or 2. [Claim 9] A method for manufacturing a balloon catheter according to claim 8, The steps include preparing a parison having radial, circumferential, and longitudinal axis directions, and having a lumen extending in the longitudinal axis direction, The method includes the step of biaxially extending the parison to produce a balloon having a proximal sleeve portion, a proximal tapered portion, a straight tube portion, a distal tapered portion, and a distal sleeve portion, and having a projection that protrudes radially outward and extends in the longitudinal axis direction, The aforementioned parison is, It has an outer layer and an inner layer made of a material with a lower Shore D hardness than the outer layer. It has a protruding region including a protruding portion that protrudes radially outward and extends in the longitudinal direction, and a non-protruding region other than the protruding region. A method for manufacturing a balloon catheter, wherein in a cross section perpendicular to the longitudinal axis, the inner layer has a small thickness portion in the non-protruding region and a large thickness portion in the protruding region having a thickness greater than the thickness of the small thickness portion.

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