Balloon catheter-use balloon, and balloon catheter provided with same

Abstract

Provided is a balloon catheter-use balloon which can improve non-slip performance for making the balloon less likely to shift from a lesion location, and also can improve scoring performance with respect to engaging with a stenotic area.　A balloon catheter-use balloon (2) includes a balloon body (20) and a projection section (28). The balloon body (20) and the projection section (28) are formed from the same material. A value of Ra1 / Ra2, which is a ratio of a value Ra1 obtained by measuring the surface roughness of the projection section (28) for a reference length in a direction (a1) parallel to a longitudinal axis direction (x1) and a value Ra2 obtained by measuring the surface roughness of the projection section (28) for a reference length in a direction (a2) perpendicular to the longitudinal axis direction (x1), is greater than 1.

Description

Balloon for balloon catheter and balloon catheter equipped with same

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

[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] In angioplasty, it can be difficult to dilate stenotic areas that have hardened due to calcification or other factors using a typical balloon catheter. Another method for dilating stenotic areas involves placing an indwelling dilation device called a stent at the stenotic area. However, this method can result in, for example, in-stent restenosis (ISR) lesions, in which excessive neointima of the blood vessel proliferates after treatment, causing recurrence of vascular stenosis. In ISR lesions, the neointima is soft and has a slippery surface, so when a typical balloon catheter is used to dilate the balloon, the balloon may shift from the lesion and damage the blood vessel.

[0004] Balloon catheters that can dilate stenotic lesions, even in lesions such as calcified lesions and ISR lesions, have been developed that have protrusions, blades, or scoring elements on the balloon to penetrate the stenotic lesion. For example, Patent Document 1 discloses a balloon with protrusions and a method for manufacturing a balloon that includes a step of forming the protrusions by welding at least a portion of the adjacent inner surfaces of the balloon where the inner surfaces are arranged facing each other. Patent Document 2 discloses a balloon with pleats formed as protrusions and a method of forming the pleats on the balloon using a mold.

[0005] JP 2017-12678 A JP 2005-511187 A

[0006] However, with the above-mentioned conventional balloons, although the protruding portion abuts the narrowed area, it is sometimes the case that it does not penetrate sufficiently into the hardened calcified lesion. In addition, it is difficult to fix the balloon to lesions such as ISR lesions, which have a slippery surface, and the balloon may slip out of place, resulting in problems such as not being able to make an incision at the intended location or damaging blood vessels other than the area to be treated.

[0007] In view of the above circumstances, the present invention aims to provide a balloon for a balloon catheter that can improve the non-slip performance of the balloon so that it is less likely to slip off the lesion, and can improve the scoring performance of the balloon to penetrate into the stenosis, and a balloon catheter equipped with the same.

[0008] The balloon for a balloon catheter according to an embodiment of the present invention that has solved the above problems is as follows: [1] A balloon for a balloon catheter having a longitudinal axis direction and a radial direction, the balloon having an outer surface and an inner surface, and a protruding portion that protrudes radially outward from the outer surface of the balloon body and extends in the longitudinal axis direction, the balloon body and the protruding portion being made of the same material, and the surface roughness of the protruding portion measured over a reference length in a direction parallel to the longitudinal axis direction is a value Ra １ and the value Ra when the surface roughness of the protrusion is measured over a reference length in a direction perpendicular to the longitudinal axis direction. ２ The ratio Ra １ / Ra ２ A balloon for a balloon catheter with a value greater than 1.

[0009] The balloon for a balloon catheter according to the embodiment of the present invention is preferably any one of [2] to [7] below. [2] The balloon for a balloon catheter according to [1], wherein, in a cross section perpendicular to the longitudinal axis direction, the protrusion has a distal region including the radially outer end and a proximal region located radially inward relative to the distal region, and when the surface roughness of the protrusion is measured over a reference length parallel to the longitudinal axis, the surface roughness of the proximal region is smaller than that of the distal region, and when the surface roughness of the protrusion is measured over a reference length perpendicular to the longitudinal axis, the surface roughness of the proximal region is smaller than that of the distal region. [3] In a cross section perpendicular to the longitudinal axis direction, the protrusion has a distal region including the radially outer end and a proximal region located radially inward relative to the distal region, and when the surface roughness of the distal region is measured over a reference length parallel to the longitudinal axis, the surface roughness of the proximal region is smaller than that of the distal region. １（先端） and the value Ra when the surface roughness of the tip region is measured over a reference length in a direction perpendicular to the longitudinal axis direction. ２（先端） The ratio Ra １（先端） / Ra ２（先端） is greater than 1, and the surface roughness of the base end region is measured over a reference length in a direction parallel to the longitudinal axis direction, and the value Ra １（基端） and the value Ra when the surface roughness of the base end region is measured over a reference length in a direction perpendicular to the longitudinal axis direction. ２（基端） The ratio Ra １（基端） / Ra ２（基端）[4] The balloon catheter balloon according to [1] or [2], wherein the value of is greater than 1. [4] The balloon catheter balloon according to [2] or [3], wherein, when the surface roughness of the base end region and the balloon main body is measured over a reference length in a direction perpendicular to the longitudinal axis, the surface roughness of the balloon main body is greater than that of the base end region. [5] The balloon catheter balloon according to any of [2] to [4], wherein, when the surface roughness of the distal end region and the balloon main body is measured over a reference length in a direction perpendicular to the longitudinal axis, the surface roughness of the balloon main body is greater than that of the distal end region. [6] The balloon catheter balloon according to any of [2] to [5], wherein, when the surface roughness of the distal end region and the balloon main body is measured over a reference length in a direction parallel to the longitudinal axis, the surface roughness of the balloon main body is less than that of the distal end region. [7] A balloon for a balloon catheter according to any one of [2] to [6], wherein when the surface roughness of the base-end region and the balloon main body is measured over a reference length parallel to the longitudinal axis direction, the surface roughness of the balloon main body is smaller than the surface roughness of the base-end region.

[0010] The present invention also provides the following: [8] A balloon catheter comprising the balloon for a balloon catheter according to any one of [1] to [7] above.

[0011] The balloon for balloon catheter and the balloon catheter described above can improve the non-slip performance of the protrusions on the outer surface of the balloon, which prevents the protrusions from slipping off the lesion, and can also improve the scoring performance of the protrusions, which bite into the stenosis. This allows for efficient dilation of the stenosis and enables safe treatment by avoiding the risk of damaging blood vessels other than the treatment target area.

[0012] 1 shows a side view of a balloon catheter according to one embodiment of the present invention. 2 shows a perspective view of a balloon for a balloon catheter according to one embodiment of the present invention. 3 shows a cross-sectional view taken along III-III in FIG. 1. 4 shows a cross-sectional view showing a modification of FIG. 3. 5 shows a roughness curve obtained when the surface roughness of the protruding portion of a balloon for a balloon catheter according to one embodiment of the present invention is measured over a reference length in a direction parallel to the longitudinal axis direction. 6 shows a roughness curve obtained when the surface roughness of the protruding portion of the balloon for a balloon catheter used in the measurement of FIG. 5 is measured over a reference length in a direction perpendicular to the longitudinal axis direction. 7 shows a perspective view of a parison before expansion according to one embodiment of the present invention. 8 shows a cross-sectional view taken along the longitudinal axis direction of a mold according to one embodiment of the present invention. 9 shows a cross-sectional view taken along IX-IX in FIG. 8.

[0013] The present invention will be described below based on the embodiments, but the present invention is not limited to the following embodiments and can be implemented with appropriate modifications within the scope of the above and below-described purposes, and all such modifications are included within the technical scope of the present invention. In addition, hatching and component symbols may be omitted in each drawing for convenience. In such cases, please refer to the specification or other drawings. Furthermore, the dimensions of various components in the drawings may differ from the actual dimensions, as priority is given to helping understand the features of the present invention.

[0014] 1. Balloon for balloon catheter A balloon for balloon catheter according to an embodiment of the present invention is a balloon for balloon catheter having a longitudinal axis direction and a radial direction, and has a balloon main body having an outer surface and an inner surface, and a protruding portion that protrudes radially outward from the outer surface of the balloon main body and extends in the longitudinal axis direction, the balloon main body and the protruding portion being made of the same material, and the surface roughness of the protruding portion is measured over a reference length in a direction parallel to the longitudinal axis direction, and the value Ra １ and the value Ra when the surface roughness of the protrusion is measured over a reference length in a direction perpendicular to the longitudinal axis. ２ The ratio Ra １ / Ra ２ The value of is greater than 1.

[0015] Dilation of a stenotic lesion using a balloon catheter is performed by delivering a balloon attached to the distal end of the balloon catheter to the stenotic lesion, inflating the balloon, and causing the protrusions on the outer surface of the balloon body to penetrate the stenotic lesion and cut open the stenotic lesion. In this case, the greater the surface roughness of the protrusions in the direction parallel to the longitudinal axis of the balloon, i.e., the direction parallel to the direction of the balloon's advancement within the blood vessel, the greater the resistance of the protrusions to the direction of balloon advancement, thereby improving the non-slip performance of the protrusions, which are less likely to slip from their intended position. On the other hand, the smaller the surface roughness of the protrusions in the direction perpendicular to the longitudinal axis of the balloon, i.e., the direction in which the protrusions enter the stenotic lesion, the less the resistance of the protrusions to their advancement into the stenotic lesion, making it easier for the protrusions to penetrate the stenotic lesion and improving scoring performance. Therefore, the value Ra when the surface roughness of the protrusions is measured over a reference length in the direction parallel to the longitudinal axis is １ and the value Ra when the surface roughness of the protrusion is measured over a reference length in a direction perpendicular to the longitudinal axis. ２ The ratio Ra １ / Ra ２ When the value is greater than 1, it is possible to obtain a balloon with improved non-slip properties and scoring properties.

[0016] In this specification, a balloon for a balloon catheter may be simply referred to as a "balloon."

[0017] Hereinafter, a balloon for a balloon catheter according to an embodiment of the present invention will be described with reference to FIGS. 1 to 6. FIG. 1 is a side view of a balloon catheter according to an embodiment of the present invention. FIG. 2 is a perspective view of a balloon for a balloon catheter according to an embodiment of the present invention, showing the distal side of the balloon. FIG. 3 is a cross-sectional view taken along III-III in FIG. 1, which is a cross-sectional view perpendicular to the longitudinal axis of a balloon for a balloon catheter according to an embodiment of the present invention. FIG. 4 is a cross-sectional view showing a modification of FIG. 3. FIG. 5 shows a roughness curve obtained by measuring the surface roughness of the protruding portions of a balloon for a balloon catheter according to an embodiment of the present invention using a laser microscope over a reference length parallel to the longitudinal axis. FIG. 6 shows a roughness curve obtained by measuring the surface roughness of the protruding portions of the balloon for a balloon catheter used in the measurement of FIG. 5 over a reference length perpendicular to the longitudinal axis using a laser microscope.

[0018] As shown in FIG. 1 , a balloon 2 is used in a balloon catheter 1. The balloon 2 is connected to the distal end of a distal shaft 31, and the balloon 2 can be expanded by introducing fluid through the lumen of the distal shaft 31, and can be deflated by discharging the fluid. To control the expansion and deflation of the balloon 2, an indeflator (balloon pressurizer) can be used to introduce or discharge fluid. The fluid may be pressurized fluid pressurized by a pump or the like. The balloon catheter 1 will be described in detail later in the section "2. Balloon Catheter."

[0019] The balloon 2 has a longitudinal axis direction x1, a circumferential direction z1 along the outer edge of the balloon 2 in a cross section perpendicular to the longitudinal axis direction x1, and a radial direction y1 connecting the centroid of the outer edge of the balloon 2 to a point on the outer edge in a cross section perpendicular to the longitudinal axis direction x1. In this specification, the direction toward the user's hand with respect to the longitudinal axis direction x1 is referred to as the proximal side, and the direction opposite to the proximal side, i.e., the direction toward the treatment subject, is referred to as the distal side.

[0020] The components and parts other than the balloon 2 each have their own longitudinal axis direction, radial direction, and circumferential direction, which may or may not be the same as the longitudinal axis direction x1, radial direction y1, and circumferential direction z1 of the balloon 2. However, for ease of understanding, this specification will be described as assuming that all components and parts have the same longitudinal axis direction, radial direction, and circumferential direction as the longitudinal axis direction x1, radial direction y1, and circumferential direction z1 of the balloon 2.

[0021] The balloon 2 has a proximal end and a distal end in the longitudinal axis direction x1, and preferably has 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, as shown in Fig. 1 . The straight tube section 23 is preferably substantially cylindrical and has 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 into a substantially conical or truncated conical shape with a diameter decreasing with increasing distance from the straight tube section 23. Because the straight tube portion 23 has the largest diameter, when the balloon 2 is expanded at a lesion such as a stenosis, the straight tube portion 23 comes into sufficient contact with the lesion, facilitating treatment such as dilation of the lesion. Furthermore, because the proximal tapered portion 22 and the distal tapered portion 24 have reduced diameters, when the balloon 2 is deflated, the outer diameters of the proximal and distal ends of the balloon 2 are reduced, thereby reducing the step between the distal shaft 31 and the balloon 2, making it easier to insert the balloon 2 into a body cavity.

[0022] The proximal tapered section 22, the straight tube section 23, and the distal tapered section 24 are sections that expand when a fluid is introduced into the balloon 2, whereas the proximal sleeve section 21 and the distal sleeve section 25 preferably do not expand. At least a portion of the proximal sleeve section 21, which does not expand, can be fixed to the distal shaft 31, and at least a portion of the distal sleeve section 25 can be fixed to the inner shaft 60, which will be described later.

[0023] The balloon 2 has a balloon body 20 having an outer surface and an inner surface, and a protrusion 28 that protrudes outward in the radial direction y1 from the outer surface of the balloon body 20 and extends in the longitudinal axis direction x1.

[0024] The balloon body 20 defines the basic shape of the balloon 2, and the protrusions 28 are preferably provided on the outer surface of the balloon body 20 in any pattern, such as linear, dotted, mesh, or spiral. Providing the protrusions 28 on the outer surface of the balloon body 20 provides the protrusions 28 with a scoring function, enabling them to create cracks in calcified stenotic areas during angioplasty and allow for expansion. The protrusions 28 also contribute to improving the strength of the balloon 2 and preventing overexpansion when pressurized.

[0025] The protrusion 28 is preferably provided on the straight tube portion 23. The protrusion 28 provided on the straight tube portion 23, which is most likely to come into contact with the lesion, makes it easier to dilate the stricture.

[0026] As shown in Figures 1 and 2, the protrusions 28 may be provided on the straight tube section 23, the tapered section, and the sleeve section, i.e., on the entire area of ​​the balloon 2 in the longitudinal axis direction x1. Providing the protrusions 28 on sections other than the straight tube section 23 can improve the strength of the balloon 2 and the effect of suppressing overexpansion during pressurization. Alternatively, although not shown, the protrusions 28 may be provided on the straight tube section 23 and not on the tapered section and the sleeve section, or may be located lower than the straight tube section 23, or may be provided on at least a portion of the tapered section and the sleeve section. Having portions of the tapered section and the sleeve section without the protrusions 28 or located lower than the straight tube section 23 can improve the passage performance of the balloon 2.

[0027] The protrusions 28 are preferably made of the same material as the balloon body 20, and the balloon body 20 and the protrusions 28 are preferably integrally molded. By making the balloon body 20 and the protrusions 28 from the same material, the flexibility of the balloon 2 can be maintained while preventing the protrusions 28 from damaging the outer surface of the balloon body 20. By integrally forming the balloon body 20 and the protrusions 28, the protrusions 28 can be prevented from falling off the balloon body 20. Alternatively, the material forming the protrusions 28 may be different from the material forming the balloon body 20, as long as it has some degree of compatibility with the material forming the balloon body 20. Such a balloon 2 can be manufactured, for example, by placing a parison obtained by extrusion molding in a mold with grooves and blow molding it. A preferred method for manufacturing a balloon is described below.

[0028] The balloon 2 may have an inner protrusion that protrudes inward in the radial direction y1 beyond the inner surface of the balloon body 20. The protrusion 28 and the inner protrusion are preferably located at the same position in the circumferential direction z1. The inner protrusion is preferably integrally molded with the balloon body 20 and the protrusion 28, and the inner protrusion is preferably formed from the same material as the balloon body 20. Alternatively, the material forming the inner protrusion may be different from the material forming the balloon body 20, as long as there is some degree of compatibility with the material forming the balloon body 20.

[0029] As shown in Fig. 3, a single protrusion 28 may be provided in the circumferential direction z1, or as shown in Fig. 4, multiple protrusions 28 may be provided in the circumferential direction z1. When the balloon 2 has multiple protrusions 28 in the circumferential direction z1, the multiple protrusions 28 are preferably spaced apart in the circumferential direction z1, and more preferably arranged at equal intervals in the circumferential direction z1. The separation distance is preferably longer than the maximum circumferential length of the protrusions 28.

[0030] In the present invention, the protrusion 28 is a portion formed to be thicker radially outward than a predetermined position on the balloon body 20. When a single protrusion 28 is provided, the predetermined position is position A facing the outer end 28T of the protrusion 28 in the radial direction y1 as shown in Figure 3. When a plurality of protrusions 28 are provided, the predetermined position is position B corresponding to the midpoint in the circumferential direction z1 between the outer ends 28T of adjacent protrusions 28 in the circumferential direction z1 as shown in Figure 4.

[0031] The maximum height of the protrusions 28 in the radial direction y1 is preferably at least 1.2 times, more preferably at least 1.5 times, and even more preferably at least 2 times the thickness of the balloon body 20 at the predetermined position, and may also be up to 100 times, 50 times, 30 times, or 10 times. If the maximum height of the protrusions 28 in the radial direction y1 is within the above range, it becomes easier to make an incision of appropriate depth in the narrowed portion, and to form a crack.

[0032] The cross-sectional shape of the protrusion 28 in a cross section perpendicular to the longitudinal axis direction x1 may be any shape, such as a triangle, a rectangle, a polygon, a semicircle, a partial circle, an approximately circle, a fan shape, a wedge shape, a convex shape, a spindle shape, or a combination thereof. Note that triangles, rectangles, and polygons include shapes with clearly defined corners and straight sides, as well as so-called rounded polygons with rounded corners and shapes with at least some curved sides. Alternatively, the cross-sectional shape of the protrusion 28 may be an irregular shape with irregularities, chips, or the like.

[0033] When the protrusions 28 are formed in a linear or dotted shape, the protrusions 28 are preferably arranged to extend along the longitudinal axis direction x1. Alternatively, the protrusions 28 may be arranged to extend in a spiral shape around the longitudinal axis.

[0034] The value Ra when the surface roughness of the protrusion 28 is measured over a reference length in a direction parallel to the longitudinal axis direction x1 １ and the value Ra when the surface roughness of the protrusion 28 is measured over a reference length in a direction perpendicular to the longitudinal axis direction x1. ２ The ratio Ra １ / Ra ２ The value of is greater than 1.

[0035] The surface roughness is the arithmetic mean roughness Ra of the roughness curve over a reference length, the reference length being 100 μm. The arithmetic mean roughness Ra corresponds to the arithmetic mean roughness Ra defined in JIS B 0601 (2001). For example, a Keyence VK-X3000 laser microscope equipped with a white light interferometer can be used for the measurement. For example, in region R in FIG. 2, the direction parallel to the longitudinal axis direction x1 of the protrusion 28 is the direction indicated by arrow a1, and the direction perpendicular to the longitudinal axis direction x1 of the protrusion 28 is the direction indicated by arrow a2 in FIGS. 2 to 4.

[0036] Surface roughness Ra in a direction parallel to the longitudinal axis direction x1 of the protrusion 28 １ is obtained by measuring a roughness curve over a reference length of 100 μm in the direction of arrow a1 and calculating the arithmetic mean roughness of the roughness curve. The position of the 100 μm reference length in the circumferential direction z1 may be any position between the base end 28B and the outer end 28T of the protrusion 28. The base end 28B of the protrusion 28 is the point on the protrusion 28 where the thickness begins to become thicker outward in the radial direction y1 than the film thickness at the predetermined position on the balloon body 20.

[0037] Surface roughness Ra in a direction perpendicular to the longitudinal axis direction x1 of the protrusion 28 ２ is obtained by measuring a roughness curve over a reference length of 100 μm in the direction of arrow a2 and calculating the arithmetic mean roughness of the roughness curve. In this case, the roughness curve may be measured over a reference length of 100 μm from the base end 28B of the protrusion 28 in a direction perpendicular to the longitudinal axis direction x1, or may be measured over a reference length of 100 μm from the outer end 28T of the protrusion 28 in a direction perpendicular to the longitudinal axis direction x1, or may be measured over a reference length of 100 μm at any position between the base end 28B and the outer end 28T. In the direction perpendicular to the longitudinal axis direction x1, the length of the surface of the protrusion 28 from the base end 28B to the outer end 28T is preferably 100 μm or more.

[0038] Figure 5 shows Ra １ An example of the roughness curve measured to obtain Ra is shown in FIG. ２ 5 and 6 also show that the surface roughness Ra in the direction parallel to the longitudinal axis direction x1 of the protrusion 28 is１ is the value Ra when the surface roughness of the protrusion 28 is measured over a reference length in a direction perpendicular to the longitudinal axis direction x1. ２ It is found to be larger than

[0039] When the balloon 2 is delivered to the stenosis site, the protrusions 28 penetrate the stenosis site and form cracks, thereby expanding the stenosis site. In this case, the greater the surface roughness of the protrusions 28 in the direction parallel to the longitudinal axis x1 of the balloon 2, i.e., the direction parallel to the direction of movement of the balloon 2 within the blood vessel, the greater the resistance of the protrusions 28 to the direction of movement of the balloon 2, thereby improving the non-slip performance of the protrusions 28, which is less likely to slip from their intended position. On the other hand, the smaller the surface roughness of the protrusions 28 in the direction perpendicular to the longitudinal axis x1 of the balloon 2, i.e., the direction in which the protrusions 28 penetrate the stenosis site, the smaller the resistance of the protrusions 28 to penetration into the stenosis site, which makes it easier for the protrusions 28 to penetrate into the stenosis site, thereby improving scoring performance. Therefore, the value Ra when the surface roughness of the protrusions 28 is measured over a reference length in the direction parallel to the longitudinal axis x1 is １ and the value Ra when the surface roughness of the protrusion 28 is measured over a reference length in a direction perpendicular to the longitudinal axis direction x1. ２ The ratio Ra １ / Ra ２ When the value is greater than 1, it is possible to obtain a balloon with improved non-slip properties and scoring properties.

[0040] Ratio Ra １ / Ra ２ An example of a configuration in which the value of Ra is greater than 1 is a configuration in which minute ridges extending in a direction perpendicular to the longitudinal axis direction x1 are alternately arranged on the surface of the protrusion 28. In such a configuration, when the roughness curve is measured in a direction parallel to the longitudinal axis direction x1, the maximum height is the length from the top of the ridge to the bottom of the ridge, so that Ra １ In addition, in this configuration, the ridges and ridges extend perpendicular to the longitudinal axis direction x1, so when the roughness curve is measured in a direction perpendicular to the longitudinal axis direction x1, the roughness curve passes through portions of the ridges and ridges that are approximately the same height or depth, and Ra ２ However, the ratio Ra １ / Ra ２The configuration in which the value of is greater than 1 is not limited to the above, and includes any configuration, such as a configuration in which more minute irregularities are arranged in a direction parallel to the longitudinal axis direction x1 and fewer are arranged in a direction perpendicular to the longitudinal axis direction x1.

[0041] Surface roughness Ra in the direction parallel to the longitudinal axis direction x1 １ is preferably determined as the average of arithmetic mean roughness values ​​obtained from roughness curves measured over a predetermined number of reference lengths at predetermined intervals in the direction perpendicular to the longitudinal axis direction x1, i.e., the circumferential direction z1. This reduces the influence of variations in surface roughness due to position in the circumferential direction z1. The predetermined intervals can be, for example, 2 μm, and the predetermined number of reference lengths can be, for example, 31. In this case, it can be said that the surface roughness was measured over an area of ​​60 μm × 100 μm.

[0042] Surface roughness Ra in the direction perpendicular to the longitudinal axis direction x1 ２ is preferably determined as the average of arithmetic mean roughness values ​​obtained from roughness curves measured at a predetermined interval along the longitudinal axis direction x1 over a predetermined number of reference lengths. This reduces the influence of variations in surface roughness due to position along the longitudinal axis direction x1. The predetermined interval can be, for example, 2 μm, and the predetermined number of reference lengths can be, for example, 31. In this case, it can be said that the surface roughness was measured over an area of ​​60 μm × 100 μm.

[0043] Surface roughness Ra in the direction parallel to the longitudinal axis direction x1 １ and the surface roughness Ra in the direction perpendicular to the longitudinal axis direction x1 ２ The surface roughness Ra in the direction parallel to the longitudinal axis x1 at the same position in the longitudinal axis direction x1 may be compared, or may be compared at different positions in the longitudinal axis direction x1, but is preferably compared at the same position in the longitudinal axis direction x1. Here, the same position means that the measurement areas when measured for a predetermined number of reference lengths at a predetermined interval overlap. The surface roughness Ra in the direction parallel to the longitudinal axis direction x1 at the same position in the longitudinal axis direction x1 is １ and the surface roughness Ra in the direction perpendicular to the longitudinal axis direction x1 ２ When comparing the ratio Ra １ / Ra ２When the value of Ra is greater than 1, the balloon 2 can have improved non-slip and scoring performance of the protrusion 28 at that position. For example, the surface roughnesses may be compared in the straight pipe section 23, and the ratio Ra １ / Ra ２ When the value of is greater than 1, the protrusions 28 arranged on the straight tube section 23 can provide the balloon 2 with improved non-slip and scoring properties, enabling more efficient dilation of the stenotic area. Note that if multiple protrusions 28 are provided, it is sufficient to measure the surface roughness of any one of the protrusions 28.

[0044] Ratio Ra １ / Ra ２ The value of is preferably 1.2 or more, more preferably 1.5 or more, and may be 1.8 or more, 2 or more, 2.2 or more, 2.4 or more, or 2.5 or more, and is preferably 5 or less, more preferably 4 or less, and even more preferably 3 or less. If it is within the above range, the balloon 2 can have improved non-slip performance and scoring performance due to the protrusions 28.

[0045] When a plurality of protrusions 28 are provided as shown in FIG. 4, the ratio Ra １ / Ra ２ It is preferable that the value of is within the above range, which allows the stricture site to be expanded more efficiently.

[0046] As shown in Figures 2 to 4, in a cross section perpendicular to the longitudinal axis direction x1, the protrusion 28 has a tip region 28t including the outer end 28T in the radial direction y1, and a base region 28b located inward in the radial direction y1 from the tip region 28t. When the surface roughness of the protrusion 28 is measured over a reference length in a direction parallel to the longitudinal axis direction x1, the surface roughness of the base region 28b is smaller than the surface roughness of the tip region 28t, and when the surface roughness of the protrusion 28 is measured over a reference length in a direction perpendicular to the longitudinal axis direction x1, it is preferable that the surface roughness of the base region 28b is smaller than the surface roughness of the tip region 28t.

[0047] Although the resistance of the protrusions 28 to the direction of advancement of the balloon 2 increases due to the high surface roughness in the direction parallel to the longitudinal axis x1, the high surface roughness of the distal end region 28t, which first comes into contact with the stenosis, makes it difficult for the protrusions 28 to deviate from their intended position when they first begin to bite into the stenosis, thereby further improving non-slip performance. Once positioning is achieved by the distal end region 28t, a smaller surface roughness in the proximal end region 28b, which enters the stenosis following the distal end region 28t, makes it easier for the entire protrusion to enter the stenosis.

[0048] The surface roughness in the direction perpendicular to the longitudinal axis direction x1 affects the resistance of the protrusion 28 to penetrating into the stenosis. Here, the distal region 28t, which first begins to bite into the stenosis, can penetrate with relatively low resistance to pushing, whereas the proximal region 28b, which penetrates in the final stage, has high resistance to pushing, making it difficult for the entire protrusion 28 to penetrate into the stenosis. However, when the surface roughness in the direction perpendicular to the longitudinal axis direction x1 is measured, the surface roughness of the proximal region 28b is smaller than that of the distal region 28t, so that the frictional resistance of the proximal region 28b can be reduced, allowing the entire protrusion 28 to penetrate into the stenosis. This further improves scoring performance.

[0049] The surface roughness of the distal region 28t and the proximal region 28b can also be measured using a method similar to the method for measuring the surface roughness of the protrusion 28. Regarding the range between the distal region 28t and the proximal region 28b, for example, a straight line can be drawn on the surface of the protrusion 28, passing through the midpoint of a line segment perpendicular to the longitudinal axis direction x1 from the base end 28B to the outer end 28T, and parallel to the longitudinal axis direction x1, with the distal region 28t being the area outward of the line in the radial direction y1, and the proximal region 28b being the area proximal to the line in the radial direction y1. Alternatively, the straight line may pass through a point distal to the midpoint of the line segment perpendicular to the longitudinal axis direction x1 from the base end 28B to the outer end 28T, or alternatively, may pass through a point proximal to the midpoint.

[0050] The surface roughness of the tip region 28t in a direction parallel to the longitudinal axis direction x1 can be determined by measuring the surface roughness near the outer end 28T of the protrusion 28 in the radial direction y1. The surface roughness is preferably determined as the average of arithmetic mean roughness values ​​obtained from roughness curves measured at predetermined intervals in the circumferential direction z1 over a predetermined number of reference lengths. The predetermined intervals may be, for example, 2 μm, and the predetermined number of reference lengths may be, for example, 31. In this case, the length of the surface of the tip region 28t in a direction perpendicular to the longitudinal axis x1, i.e., in the circumferential direction z1, is preferably 60 μm or greater. Alternatively, if the length of the surface of the tip region 28t in a direction perpendicular to the longitudinal axis x1, i.e., in the circumferential direction z1, is less than 60 μm, it is possible to narrow the predetermined interval or reduce the predetermined number of reference lengths, for example.

[0051] The surface roughness of the base end region 28b in a direction parallel to the longitudinal axis direction x1 can be determined by measuring the surface roughness of the protrusion 28 in the radial direction y1 near the base end 28B. The surface roughness is preferably determined as the average of arithmetic mean roughness values ​​obtained from roughness curves measured at predetermined intervals in the circumferential direction z1 for a predetermined number of reference lengths. The predetermined intervals can be, for example, 2 μm, and the predetermined number of reference lengths can be, for example, 31. In this case, the length of the surface of the base end region 28b in a direction perpendicular to the longitudinal axis direction x1, i.e., in the circumferential direction z1, is preferably 60 μm or greater. Alternatively, if the length of the surface of the base end region 28b in a direction perpendicular to the longitudinal axis direction x1, i.e., in the circumferential direction z1, is less than 60 μm, it is possible to narrow the predetermined interval or reduce the predetermined number of reference lengths, for example.

[0052] The surface roughness of the tip region 28t in the direction perpendicular to the longitudinal axis direction x1 is obtained by measuring a roughness curve of a reference length of 100 μm in the direction perpendicular to the longitudinal axis direction x1 from the vicinity of the outer end 28T in the radial direction y1 of the protrusion 28. In this case, the surface roughness is preferably determined as the average of arithmetic mean roughnesses obtained from roughness curves measured over a predetermined number of reference lengths at predetermined intervals in the longitudinal axis direction x1.

[0053] The surface roughness of the base end region 28b in the direction perpendicular to the longitudinal axis direction x1 is obtained by measuring a roughness curve of a reference length of 100 μm in the direction perpendicular to the longitudinal axis direction x1 from the vicinity of the base end 28B in the radial direction y1 of the protrusion 28. In this case, the surface roughness is preferably determined as the average of arithmetic mean roughness values ​​obtained from roughness curves measured over a predetermined number of reference lengths at predetermined intervals in the longitudinal axis direction x1.

[0054] When measuring the surface roughness in a direction perpendicular to the longitudinal axis direction x1 as described above, if the length from the base end 28B of the protrusion 28 to the outer end 28T in the direction perpendicular to the longitudinal axis direction x1, i.e., the circumferential direction z1, is twice the reference length of 100 μm, i.e., less than 200 μm, the measurement area of ​​the base end region 28b and the measurement area of ​​the tip region 28t will partially overlap in the direction perpendicular to the longitudinal axis direction x1, but by measuring the surface roughness using the above method, the roughness of the tip region 28t and the base end region 28b can be obtained.

[0055] Alternatively, when the length from the base end 28B of the protrusion 28 to the outer end 28T in the direction perpendicular to the longitudinal axis direction x1, i.e., the circumferential direction z1, is twice the reference length of 100 μm, i.e., exceeds 200 μm, the surface roughness of the tip region 28t in the direction perpendicular to the longitudinal axis direction x1 can be obtained by measuring a roughness curve of a reference length of 100 μm in the direction perpendicular to the longitudinal axis direction x1 at an arbitrary position closer to the outer end 28T than a point 100 μm from the base end 28B in the direction perpendicular to the longitudinal axis direction x1 toward the outer end 28T. The start and end points of the reference length may be located at arbitrary points between the point 100 μm from the base end 28B and the outer end 28T in the direction perpendicular to the longitudinal axis direction x1, i.e., the circumferential direction z1.

[0056] The surface roughness of the distal end region 28t and the proximal end region 28b may be compared at the same position in the longitudinal axis direction x1 or at different positions in the longitudinal axis direction x1, but it is preferable to compare them at the same position in the longitudinal axis direction x1. Here, "the same position" may mean the exact same position in the longitudinal axis direction x1, or may mean that the positions of the measurement regions in the distal end region 28t and the proximal end region 28b at least partially overlap in the longitudinal axis direction x1. If the surface roughness of the proximal end region 28b arranged at the same position in the longitudinal axis direction x1 is smaller than the surface roughness of the distal end region 28t, the protrusion 28 at that position can achieve the above-mentioned effect. For example, the surface roughness of each region may be compared in the straight pipe portion 23.

[0057] The surface roughness of the proximal region 28b in the direction parallel to the longitudinal axis x1 is preferably 0.9 times or less, more preferably 0.8 times or less, even more preferably 0.6 times or less, or may be 0.5 times or less, or 0.4 times or less, or is preferably 0.01 times or more, more preferably 0.05 times or more, and even more preferably 0.1 times or more, of the surface roughness of the distal region 28t in the direction parallel to the longitudinal axis x1. If the surface roughness is within the above range, it becomes easier to obtain a balloon 2 with improved non-slip performance due to the distal region 28t.

[0058] The surface roughness of the proximal region 28b in the direction perpendicular to the longitudinal axis x1 is preferably 0.9 times or less, more preferably 0.8 times or less, even more preferably 0.6 times or less, or may be 0.5 times or less, or 0.4 times or less, or is preferably 0.01 times or more, more preferably 0.05 times or more, and even more preferably 0.1 times or more, of the surface roughness of the distal region 28t in the direction perpendicular to the longitudinal axis x1. If the surface roughness is within the above range, the balloon 2 can be configured so that the entire protrusion 28 can easily penetrate into the stenosis.

[0059] 4, when a plurality of protrusions 28 are provided, it is preferable that the distal end regions 28t and proximal end regions 28b of all of the protrusions 28 satisfy the above relationship, which makes it easier to effectively dilate the stricture.

[0060] In a cross section perpendicular to the longitudinal axis direction x1, the protrusion 28 has a tip region 28t including an outer end 28T in the radial direction y1 and a base region 28b located inward in the radial direction y1 from the tip region 28t, and the surface roughness of the tip region 28t is measured over a reference length in a direction parallel to the longitudinal axis direction x1 as a value Ra １（先端） and the value Ra when the surface roughness of the tip region 28t is measured over a reference length in a direction perpendicular to the longitudinal axis direction x1. ２（先端） The ratio Ra １（先端） / Ra ２（先端） The value of is greater than 1, and the surface roughness of the base end region 28b is measured over a reference length in a direction parallel to the longitudinal axis direction x1. １（基端） and the value Ra when the surface roughness of the base end region 28b is measured over a reference length in a direction perpendicular to the longitudinal axis direction x1. ２（基端） The ratio Ra １（基端） / Ra ２（基端） Preferably, the value of is greater than 1.

[0061] In both the tip region 28t and the base region 28b, the surface roughness in the direction parallel to the longitudinal axis direction x1 is greater than the surface roughness in the direction perpendicular to the longitudinal axis direction x1, making it easier to create a balloon 2 with improved both non-slip performance and scoring performance.

[0062] When the surface roughness of the proximal region 28b in the direction perpendicular to the longitudinal axis x1 is smaller than the surface roughness of the distal region 28t in the direction perpendicular to the longitudinal axis x1, it is preferable that the surface roughness of the balloon body 20 be greater than that of the proximal region 28b when measured over a reference length in the direction perpendicular to the longitudinal axis x1. In the balloon 2 according to the present invention, the protrusion 28 can easily penetrate the narrowed portion, but because the surface roughness of the balloon body 20 in the direction perpendicular to the longitudinal axis x1 is greater than that of the proximal region 28b, the balloon body 20 is prevented from penetrating the narrowed portion as well, thereby preventing the crack from becoming unnecessarily wide.

[0063] The surface roughness of the balloon main body 20 in the direction perpendicular to the longitudinal axis direction x1 is preferably at least 1.2 times, more preferably at least 1.5 times, even more preferably at least 2 times, particularly preferably at least 3 times, and preferably at most 10 times, more preferably at most 9 times, and even more preferably at most 8 times the surface roughness of the base end region 28b in the direction perpendicular to the longitudinal axis direction x1.

[0064] If the surface roughness of the base end region 28b in the direction perpendicular to the longitudinal axis x1 is smaller than the surface roughness of the distal end region 28t in the direction perpendicular to the longitudinal axis x1, when the surface roughness of the distal end region 28t and the balloon main body 20 is measured over a reference length in the direction perpendicular to the longitudinal axis x1, the surface roughness of the balloon main body 20 is preferably greater than the surface roughness of the distal end region 28t. If the surface roughness of the balloon main body 20 is even greater than the surface roughness of the distal end region 28t, which is greater than the surface roughness of the base end region 28b, it is easier to prevent the balloon main body 20 from penetrating the narrowed portion, and it becomes easier to insert only the protruding portion 28 into the narrowed portion and make the desired incision.

[0065] The surface roughness of the balloon main body 20 in the direction perpendicular to the longitudinal axis direction x1 is preferably at least 1.05 times the surface roughness of the tip region 28t in the direction perpendicular to the longitudinal axis direction x1, more preferably at least 1.1 times, even more preferably at least 1.2 times, particularly preferably at least 1.5 times, and preferably at most 8 times, more preferably at most 7 times, and even more preferably at most 6 times.

[0066] If the surface roughness of the proximal region 28b in the direction parallel to the longitudinal axis x1 is smaller than the surface roughness of the distal region 28t in the direction parallel to the longitudinal axis x1, when the surface roughness of the distal region 28t and the balloon main body 20 is measured over a reference length in the direction parallel to the longitudinal axis x1, it is preferable that the surface roughness of the balloon main body 20 be smaller than that of the distal region 28t. Since the greater the surface roughness in the direction parallel to the longitudinal axis x1, the more improved the non-slip performance, the greater the surface roughness of the distal region 28t, and the non-slip performance of the protrusions 28 can be ensured. However, the smaller the surface roughness of the balloon main body 20 in the direction parallel to the longitudinal axis x1, which has a larger contact area with the blood vessel wall during delivery of the balloon 2, the easier it is to insert the balloon 2 into the blood vessel lumen during delivery.

[0067] The surface roughness of the balloon main body 20 in a direction parallel to the longitudinal axis direction x1 is preferably 0.6 times or less, more preferably 0.5 times or less, even more preferably 0.4 times or less, or may be 0.3 times or less, or 0.2 times or less, or is preferably 0.03 times or more, more preferably 0.05 times or more, even more preferably 0.08 times or more, or may be 0.1 times or more, of the surface roughness of the tip region 28t in a direction parallel to the longitudinal axis direction x1.

[0068] If the surface roughness of the proximal region 28b in the direction parallel to the longitudinal axis x1 is smaller than the surface roughness of the distal region 28t in the direction parallel to the longitudinal axis x1, then when the surface roughness of the proximal region 28b and the balloon body 20 is measured over a reference length in the direction parallel to the longitudinal axis x1, the surface roughness of the balloon body 20 is preferably smaller than that of the proximal region 28b. Having a smaller surface roughness than the proximal region 28b, which is smaller than the surface roughness of the distal region 28t, can further improve the insertability of the balloon 2 through the blood vessel lumen during delivery.

[0069] The surface roughness of the balloon main body 20 in a direction parallel to the longitudinal axis direction x1 is preferably 0.99 times or less, more preferably 0.8 times or less, even more preferably 0.7 times or less, and preferably 0.3 times or more, more preferably 0.4 times or more, and even more preferably 0.5 times or more of the surface roughness of the base end region 28b in a direction parallel to the longitudinal axis direction x1.

[0070] Examples of materials constituting the balloon body 20 and the protrusions 28 include polyolefin-based resins such as polyethylene, polypropylene, and ethylene-propylene copolymer; polyester-based resins such as polyethylene terephthalate and polyester elastomer; polyurethane-based resins such as polyurethane and polyurethane elastomer; polyphenylene sulfide-based resins; polyamide-based resins such as polyamide and polyamide elastomer; fluorine-based resins; silicone-based resins; and natural rubber such as latex rubber. These materials may be used alone or in combination. Among these, polyamide-based resins, polyester-based resins, and polyurethane-based resins are preferred, with polyamide-based resins such as nylon 12 and nylon 11 being more preferred, and nylon 12 being particularly preferred. From the standpoint of thinning and flexibility of the balloon body 20, it is preferable to use an elastomer resin, and polyamide elastomers such as polyamide ether elastomers are preferably used.

[0071] Next, a method for manufacturing the balloon 2 will be described with reference to Figures 7 to 9. Figure 7 is a perspective view of a parison before expansion according to one embodiment of the present invention. Figure 8 is a cross-sectional view of a mold according to one embodiment of the present invention taken along the longitudinal axis, and Figure 9 is a cross-sectional view taken along line IX-IX of Figure 8.

[0072] The balloon 2 can be manufactured by placing the parison 200 in a mold 300 and blow-molding the parison 200.

[0073] As shown in Figure 7, the parison 200 is made of resin and is a tubular member having an inner cavity 205. The parison 200 is produced, for example, by extrusion molding. The parison 200 has a first end 201 and a second end 202 and extends in a longitudinal axis direction x2 from the first end 201 to the second end 202. Like the balloon 2, the parison 200 has a radial direction y2 and a circumferential direction z2.

[0074] The cross-sectional shape of the parison 200 perpendicular to the longitudinal axis direction x2 may be substantially uniform along the longitudinal axis direction x2. This increases the productivity of the parison 200. Alternatively, although not shown, the cross-sectional shape of the parison 200 perpendicular to the longitudinal axis direction x2 may vary depending on the position along the longitudinal axis direction x2. For example, the parison 200 may be molded so that the outer diameter of a portion along the longitudinal axis direction x2 is larger than that of other portions, and the portion with the larger outer diameter becomes the straight tube portion 23 of the balloon 2. In order to manufacture parisons 200 having outer diameters that vary depending on the position along the longitudinal axis direction x2, blow molding may be performed in advance using a mold.

[0075] 7, the parison 200 before expansion may have protruding portions 208 whose thickness increases outward in the radial direction y2. The protruding portions 208 are brought into contact with grooves 310 of a mold 300, which will be described later, to facilitate the formation of the protruding portions 28 of the balloon 2.

[0076] 7, a plurality of protrusions 208 may be provided in the circumferential direction z2, or although not shown, a single protrusion 208 may be provided in the circumferential direction z2. When a plurality of protrusions 208 are provided in the circumferential direction z2, the plurality of protrusions 208 are preferably spaced apart in the circumferential direction z2, and more preferably arranged at equal intervals in the circumferential direction z2.

[0077] For the material constituting the parison 200, the above description of the resin constituting the balloon body 20 and the protrusions 28 can be referred to.

[0078] 8 , the mold 300 has a longitudinal axis direction x3, a radial direction y3, and a circumferential direction z3, and has a cavity 305 extending in the longitudinal axis direction x3 and into which the parison 200 is inserted. It is preferable that a portion of the parison 200 in the longitudinal axis direction x2 is disposed in the cavity 305 of the mold 300. It is preferable that the longitudinal axis direction x2 of the parison 200 and the longitudinal axis direction x3 of the mold 300 coincide with each other. This makes it easier to place the parison 200 in the cavity 305 of the mold 300.

[0079] The mold 300 preferably has, in the longitudinal axis direction x3, a mold straight pipe section 300C that forms the straight pipe section 23 of the balloon 2, two mold tapered sections 300T that are arranged on both sides of the mold straight pipe section 300C and form tapered sections of the balloon 2, and two mold sleeve sections 300S that are arranged further from the mold straight pipe section 300C than the mold tapered sections 300T and form sleeve sections of the balloon 2. This allows for a configuration in which the mold straight pipe section 300C forms the straight pipe section 23 of the balloon 2, the mold tapered sections 300T form the proximal tapered section 22 and the distal tapered section 24 of the balloon 2, and the mold sleeve sections 300S form the proximal sleeve section 21 and the distal sleeve section 25 of the balloon 2.

[0080] The mold 300 may be composed of one member or multiple members. As shown in Fig. 8, the mold 300 may be composed of multiple mold members connected to each other in the longitudinal axis direction x3. For example, the mold straight pipe section 300C, the mold tapered section 300T, and the mold sleeve section 300S may each be different mold members connected to each other in the longitudinal axis direction x3. The mold 300 may also be separable in the radial direction y3.

[0081] 9 , the inner cavity 305 of the mold 300 is preferably formed from a groove 310 recessed outward in the radial direction y3 and extending in the longitudinal axis direction x3, and a cylindrical wall portion 320 other than the groove 310. A balloon 2 having a protrusion 28 can be manufactured by inserting the parison 200 into the groove 310 of the mold 300 and introducing a fluid into the inner cavity 205 of the parison 200 to blow-mold the parison 200.

[0082] The groove 310 is preferably provided in the mold straight tube portion 300C of the mold 300. This allows the protrusion 28 to be formed in the straight tube portion 23 of the balloon 2, thereby improving the efficiency with which the balloon 2 incises the stricture site.

[0083] The grooves 310 may also be provided in at least one of the two first mold tapered portions 300T of the mold 300. This allows the protrusions 28 to be formed in the proximal tapered portion 22 and / or the distal tapered portion 24 of the balloon 2, thereby improving the non-slip performance of the balloon 2 against the stenosis portion. When the grooves 310 are provided in the mold tapered portion 300T, the depth of the grooves 310 provided in the mold tapered portion 310T is preferably equal to or less than the depth of the grooves 310 provided in the mold straight tube portion 300C. This allows the height of the protrusions 28 formed in the proximal tapered portion 22 and / or the distal tapered portion 24 of the balloon 2 to be equal to or less than the height of the protrusions 28 formed in the straight tube portion 23, improving the passage performance of the balloon 2. If the mold tapered portion 300T does not have the groove portion 310, the protrusions 28 will not be formed or will be formed with a low height in the proximal tapered portion 22 and / or distal tapered portion 24 of the balloon 2, thereby further improving the passage performance of the balloon 2. In this case, an inner protrusion may be formed in the portion where the protrusions 28 are not formed or where the protrusions 28 are formed with a low height.

[0084] The groove 310 may or may not be provided in the mold sleeve portion 300S of the mold 300. If the mold sleeve portion 300S has the groove 310, the depth of the groove 310 in the mold sleeve portion 300S is preferably shallower than the depth of the groove 310 in the mold straight pipe portion 300C. This allows the height of the protrusion 28 formed in the proximal sleeve portion 21 and / or the distal sleeve portion 25 to be lower than the height of the protrusion 28 formed in the straight pipe portion 23, thereby improving the passage performance of the balloon 2. If the mold sleeve portion 300S does not have the groove 310, the protrusion 28 cannot be formed in the proximal sleeve portion 21 and / or the distal sleeve portion 25 of the balloon 2, thereby further improving the passage performance of the balloon 2. In this case, an inner protrusion may be formed in a portion where no protrusion 28 is formed or where the protrusion 28 is formed at a low height.

[0085] Surface roughness ratio Ra of the protruding portion 28 of the balloon 2 １ / Ra２ One configuration for making the value of x1 greater than 1 is to form alternating minute ridges and ridges on the surface of the protrusion 28, the ridges extending in a direction perpendicular to the longitudinal axis direction x1. A method for manufacturing this configuration may include, for example, polishing the inner cavity 305 of the groove 310 of the mold 300 in a direction perpendicular to the longitudinal axis direction x3, i.e., in the circumferential direction z3, to form minute polishing marks in the direction perpendicular to the longitudinal axis direction x3, i.e., in the circumferential direction z3.

[0086] Methods for manufacturing a balloon 2 having different surface roughnesses in the base end region 28b and the tip end region 28t of the protrusion 28 include a method of forming polishing marks so that the surface roughnesses of the groove base end region 310b and the groove tip region 310t of the groove portion 310 of the mold 300 are different.

[0087] A method for manufacturing a balloon 2 so that the surface roughness of the balloon main body 20 is greater than the surface roughness of the protrusions 28 when measured over a reference length perpendicular to the longitudinal axis direction x1, and is less than the surface roughness of the protrusions 28 when measured over a reference length parallel to the longitudinal axis direction x1, includes a method of polishing the inner tube wall 320 that forms the balloon main body 20 in the longitudinal axis direction x3 to form minute polishing marks in the longitudinal axis direction x3.

[0088] The material constituting the mold 300 is preferably a metal, and more preferably iron, copper, aluminum, or an alloy thereof. For example, an iron alloy may be stainless steel, a copper alloy may be brass, and an aluminum alloy may be duralumin.

[0089] 2. Balloon Catheter A balloon catheter 1 according to an embodiment of the present invention includes the above-described balloon catheter balloon 2. As described in the above section "1. Balloon for Balloon Catheter," the balloon 2 is connected to the distal end of the distal shaft 31, as shown in FIG.

[0090] 1 shows a so-called rapid exchange type balloon catheter 1 having a guidewire port 50 midway from the distal side to the proximal side of the shaft 30 and an inner shaft 60 that functions as a guidewire passage from the guidewire port 50 to the distal side of the shaft 30. The balloon catheter 1 preferably has a distal shaft 31 and a proximal shaft 32, or the distal shaft 31 and the proximal shaft 32 may be separate members, and the proximal end of the distal shaft 31 may be connected to the distal end of the proximal shaft 32 to form the shaft 30 that extends from the balloon 2 to the proximal end of the balloon catheter 1. Alternatively, a single shaft 30 may extend from the balloon 2 to the proximal end of the balloon catheter 1, or the distal shaft 31 and the proximal shaft 32 may be composed of multiple tubular members.

[0091] It is preferable that the shaft 30 has a fluid flow path and a guidewire insertion path therein. To configure the shaft 30 to have a fluid flow path and a guidewire insertion path therein, for example, an inner shaft 60 disposed inside the shaft 30 can function as a guidewire insertion path, and the space between the shaft 30 and the inner shaft 60 can function as a fluid flow path. In such a configuration, it is preferable that the inner shaft 60 extends from the distal end of the shaft 30 and passes through the balloon 2, and the distal side of the balloon 2 is connected to the inner shaft 60, and the proximal side of the balloon 2 is connected to the shaft 30.

[0092] The shaft 30 is preferably made of resin, metal, or a combination of resin and metal. Using resin as the constituent material of the shaft 30 facilitates imparting flexibility and elasticity to the shaft 30. Furthermore, using metal as the constituent material of the shaft 30 can improve the deliverability of the balloon catheter 1. Examples of resins that can be used to form the shaft 30 include polyamide resins, polyester resins, polyurethane resins, polyolefin resins, fluorine-based 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 form the shaft 30 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 30 is composed of a distal shaft 31 and a proximal shaft 32 that are separate members, the distal shaft 31 may be made of resin, and the proximal shaft 32 may be made of metal, for example. The shaft 30 may also have a laminated construction of different materials or the same materials.

[0093] The balloon 2 and the shaft 30 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 2 and the shaft 30 and crimping the end. Among these, it is preferable that the balloon 2 and the shaft 30 are joined by welding. By welding the balloon 2 and the shaft 30, the bond between the balloon 2 and the shaft 30 is less likely to come loose even when the balloon 2 is repeatedly expanded or contracted, and the bond strength can be improved.

[0094] A tip member 70 is preferably 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 as a separate member from the inner shaft 60 and connected to the distal end of the balloon 2, or the inner shaft 60 may extend distally beyond the distal end of the balloon 2 and function as the tip member 70.

[0095] Radiopaque markers 80 may be placed on the inner shaft 60 inside the balloon 2 at the location of the balloon 2 in the longitudinal axis direction x1 so that the position of the balloon 2 can be confirmed under X-ray fluoroscopy. The radiopaque markers 80 are preferably placed at positions corresponding to both ends of the straight tube section 23 of the balloon 2, or may be placed at a position corresponding to the center of the straight tube section 23 in the longitudinal axis direction x1.

[0096] A hub 5 may be provided on the proximal side of the shaft 30, and the hub 5 preferably has a fluid injection section 6 that communicates with a flow path for fluid supplied inside the balloon 2.

[0097] The shaft 30 and the hub 5 can be joined by, for example, bonding with an adhesive or welding. Of these, it is preferable that the shaft 30 and the hub 5 are joined by adhesive. By bonding the shaft 30 and the hub 5 together, the bond strength between the shaft 30 and the hub 5 can be increased, thereby improving the durability of the balloon catheter 1, even when the shaft 30 and the hub 5 are made of different materials, such as when the shaft 30 is made of a highly flexible material and the hub 5 is made of a highly rigid material.

[0098] Although not shown, the present invention can also be applied to so-called over-the-wire balloon catheters, which have a guidewire passage extending from the distal to the proximal side of the shaft. In the case of over-the-wire balloon catheters, the inflation lumen and the guidewire lumen preferably extend to a hub located proximally, and the proximal openings of each lumen are preferably provided in a bifurcated hub.

[0099] In the case of a rapid exchange type catheter, it is preferable that an appropriate coating is applied to the outer wall of the distal shaft 31 and / or the proximal shaft 32, and it is more preferable that a coating is applied to both the distal shaft 31 and the proximal shaft 32. 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.

[0100] The coating can be a hydrophilic coating or a hydrophobic coating depending on the purpose, and can be applied by immersing the shaft 30 in a hydrophilic or hydrophobic coating agent, by applying a hydrophilic or hydrophobic coating agent to the outer wall of the shaft 30, or by covering the outer wall of the shaft 30 with a hydrophilic or hydrophobic coating agent. The coating agent may contain drugs or additives.

[0101] 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.

[0102] 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.

[0103] This application claims the benefit of priority based on Japanese Patent Application No. 2022-133113, filed on August 24, 2022. The entire contents of the specification of Japanese Patent Application No. 2022-133113, filed on August 24, 2022, are incorporated herein by reference.

[0104] 1: Balloon catheter 2: Balloon for balloon catheter 5: Hub 6: Fluid injection section 20: Balloon main body section 21: Proximal sleeve section 22: Proximal tapered section 23: Straight tube section 24: Distal tapered section 25: Distal sleeve section 28: Protruding section 28b: Base end region 28B: Base end 28t: Tip region 28T: Outer end 30: Shaft 31: Distal shaft 32: Proximal shaft 50: Guidewire port 60: Inner shaft 70: Tip member 80: Radiopaque marker 200: Parison 201: First end of parison 202: Second end of parison 205: Lumen of parison 208: Protruding section of parison 300: Mold 300C: Mold straight tube section 300S: Mold sleeve section 300T: Mold tapered section 305: Mold cavity 310: Groove portion 310b: Groove base region 310t: Groove tip region 320: Inner cylinder wall portion a1: Direction parallel to the longitudinal axis direction of the balloon a2: Direction perpendicular to the longitudinal axis direction of the balloon x1: Longitudinal axis direction of the balloon y1: Radial direction of the balloon z1: Circumferential direction of the balloon x2: Longitudinal axis direction of the parison y2: Radial direction of the parison z2: Circumferential direction of the parison x3: Longitudinal axis direction of the mold y3: Radial direction of the mold z3: Circumferential direction of the mold

Claims

1. A balloon for a balloon catheter having a longitudinal axis direction and a radial direction, It has a balloon body portion having an outer surface and an inner surface, and a protruding portion that extends radially outward from the outer surface of the balloon body portion and extends in the longitudinal direction, The balloon body and the protruding portion are made of the same material. The surface roughness of the aforementioned protrusion is measured as the arithmetic mean roughness Ra of the roughness curve over a reference length of 100 μm in the direction parallel to the longitudinal axis. １ The surface roughness of the protruding portion is measured as the arithmetic mean roughness Ra of the roughness curve over a reference length of 100 μm in the direction perpendicular to the longitudinal axis, and the value Ra is... ２ Ratio Ra １ / Ra ２ A balloon catheter balloon with a value greater than 1.

2. In the cross-section perpendicular to the longitudinal axis, the protrusion has a tip region including the radially outer end and a base region located radially inward from the tip region. When the surface roughness of the protruding portion is measured with respect to a reference length in a direction parallel to the longitudinal axis, the surface roughness of the base region is smaller than the surface roughness of the tip region. The balloon for a balloon catheter according to claim 1, wherein when the surface roughness of the protruding portion is measured with respect to a reference length perpendicular to the longitudinal axis direction, the surface roughness of the proximal region is smaller than the surface roughness of the tip region.

3. In the cross-section perpendicular to the longitudinal axis, the protrusion has a tip region including the radially outer end and a base region located radially inward from the tip region. The value Ra obtained when the surface roughness of the tip region is measured with respect to a reference length in a direction parallel to the longitudinal axis direction. １（先端） The surface roughness of the tip region is measured with respect to a reference length perpendicular to the longitudinal axis, and the value Ra is... ２（先端） Ratio Ra １（先端） / Ra ２（先端） The value is greater than 1, The value Ra when measuring the surface roughness of the proximal region with respect to a reference length in a direction parallel to the longitudinal axis １（基端） and the value Ra when measuring the surface roughness of the proximal region with respect to a reference length in a direction perpendicular to the longitudinal axis ２（基端） The ratio Ra １（基端） / Ra ２（基端） The balloon for a balloon catheter according to claim 1 or 2, wherein the value of is greater than 1.

4. The balloon for a balloon catheter according to claim 2, wherein when the surface roughness of the proximal region and the balloon body is measured with respect to a reference length perpendicular to the longitudinal axis, the surface roughness of the balloon body is greater than the surface roughness of the proximal region.

5. The balloon for a balloon catheter according to claim 2, wherein when the surface roughness of the tip region and the balloon body is measured with respect to a reference length perpendicular to the longitudinal axis, the surface roughness of the balloon body is greater than the surface roughness of the tip region.

6. The balloon for a balloon catheter according to claim 2, wherein when the surface roughness of the tip region and the balloon body is measured with respect to a reference length in a direction parallel to the longitudinal axis, the surface roughness of the balloon body is smaller than the surface roughness of the tip region.

7. The balloon for a balloon catheter according to claim 2, wherein when the surface roughness of the proximal region and the balloon body is measured with respect to a reference length in a direction parallel to the longitudinal axis, the surface roughness of the balloon body is smaller than the surface roughness of the proximal region.

8. A balloon catheter comprising a balloon for a balloon catheter according to any one of claims 1, 2, 4 to 7.