Balloon for balloon catheter

Abstract

Provided is a balloon for a balloon catheter that can be easily inserted into a body cavity, has good pushability and enables easy incision of a stenosis part.　This balloon (1) for a balloon catheter comprises a balloon body (20), said balloon body (20) being provided with a protrusion (60) that protrudes outward from the outer surface along the radial direction y in a straight tube part (23) and a proximal tapered part (22) and extends along the longitudinal axial direction x, wherein the ratio [W1 / H1] between the height H1 of the protrusion (60) and the width W1 of the protrusion (60) in the straight tube part (23) is larger than the ratio [W2 / H2] between the height H2 of the protrusion (60) and the width W2 of the protrusion (60) in the proximal tapered part (22).

Description

[Technical Field]

[0001] The present invention relates to a balloon for a balloon catheter. [Background technology]

[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, conventional balloon catheters can be difficult to dilate stenotic areas that have hardened due to calcification or other factors. While a method of dilating stenotic areas by placing an indwelling dilation device called a stent at the stenotic area is also used, this treatment can sometimes result in excessive neointima growth in the blood vessel, causing recurrence of vascular stenosis, a condition known as in-stent restenosis (ISR). In ISR lesions, the neointima is soft and has a slippery surface, so when a conventional balloon catheter is used to dilate the balloon, it can slip out of position and damage the blood vessel.

[0004] Balloon catheters that can dilate stenotic lesions, even in calcified or ISR lesions, have been developed, including balloon catheters with protrusions, blades, or scoring elements that penetrate the stenotic lesion. For example, Patent Document 1 discloses a balloon catheter in which the protrusions located on the distal tapered section protrude more than the protrusions located on the straight section. Patent Document 2 also discloses a balloon catheter in which an expansion element connected to the outer surface of the balloon by a connector has a first effective width and a second effective width, and the first effective width is less than the second effective width. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2020 / 012850 Brochure [Patent Document 2] Special Publication No. 2011-513031 Summary of the Invention [Problem to be solved by the invention]

[0006] A balloon catheter is inserted into a body cavity in a deflated state and delivered through the body cavity to the treatment site. During delivery, the balloon's movement is controlled by transmitting operations from the proximal end to the distal end where the balloon is located. In this case, ease of insertion into the body cavity and ease of transmission of operations from the proximal end to the distal end (high pushability) can improve the safety of treatment, shorten treatment time, and enable treatment with less strain on the patient. Furthermore, once the balloon is delivered to the treatment site, it is required to be able to efficiently and easily incise the stricture. However, conventional balloon catheters have room for improvement in terms of ease of insertion into the body cavity, pushability, and ease of incising the stricture.

[0007] In view of the above circumstances, an object of the present invention is to provide a balloon for a balloon catheter that is easy to insert into a body cavity, has good pushability, and can easily incise a stricture. [Means for solving the problem]

[0008] One embodiment of a balloon catheter balloon of the present invention that solves the above-mentioned problems comprises a balloon body having an outer surface and an inner surface, a longitudinal axis direction, a radial direction connecting a point on the outer surface and the centroid of a diagram outlining the outer shape of the balloon body in an expanded state in a cross section perpendicular to the longitudinal axis direction, and a circumferential direction along the outer periphery of the balloon body in an expanded state in the radial cross section. The balloon body has a straight tube section, a proximal tapered section located proximal to the straight tube section, and a distal tapered section located distal to the straight tube section. The balloon body has protruding portions at the straight tube section and the proximal tapered section that protrude radially outward from the outer surface of the balloon body and extend in the longitudinal axis direction, and the ratio W1 / H1 of the height H1 of the protruding portion to the width W1 of the protruding portion at the straight tube section is greater than the ratio W2 / H2 of the height H2 of the protruding portion to the width W2 of the protruding portion at the proximal tapered section. (Here, the height and width of the protrusion are defined as follows: In the radial cross section, the circumscribed circle C of the balloon body b and the radius of the circumscribed circle C b The circumscribing circle C of the protrusion that shares a center with p The difference between the radius of the protrusion and the radius of the protrusion is the height of the protrusion. In the radial cross section, the circumscribed circle C b The width of the protrusion is the maximum length of the arc inside the outline of the protrusion among the circumferences of the concentric circles that share the same center as

[0009] The width W1 of the protrusion in the straight tube section is preferably wider than the width W2 of the protrusion in the proximal tapered section.

[0010] The ratio W1 / H1 in the straight pipe portion is preferably 0.2 or more and 5 or less.

[0011] The ratio W2 / H2 in the proximal tapered portion is preferably 0.2 or more and 5 or less.

[0012] In the radial cross section, the protrusion of the straight pipe section has a tip, and the width of the tip of the protrusion is W T and the width W1 of the protrusion T It is preferable that / W1 is 0.5 or less. (Here, the width of the tip of the protrusion is defined as follows: In the radial cross section, the circumscribed circle C p The circumscribing circle C is a concentric circle that shares a common center with p The width of the tip is the length of the arc inside the outline of the protrusion on the circumference of a circle with a radius that is 95% of the radius of the tip.)

[0013] The height H1 of the protruding portion of the straight pipe section is preferably at least 0.1 mm or more.

[0014] In a radial cross section, the protruding portion of the straight pipe portion has a tip end, and the tip end preferably has an angle of 135° or less.

[0015] It is preferable that the protruding portion of the straight tube portion and the protruding portion of the proximal tapered portion extend continuously in the longitudinal axis direction.

[0016] The distal tapered portion has a protrusion, and the height H3 of the protrusion of the distal tapered portion is preferably smaller than the height H1 of the protrusion of the straight tube portion. In this case, it is preferable that the protrusion of the straight tube portion and the protrusion of the distal tapered portion extend continuously in the longitudinal axis direction.

[0017] The distal tapered portion preferably has an inward protrusion that protrudes radially inward beyond the inner surface of the balloon body and extends in the longitudinal direction, and in this case, the distal tapered portion preferably has a protrusion, and the protrusion of the distal tapered portion and the inward protrusion are preferably located at the same circumferential position.

[0018] The protrusions are preferably made of the same material as the balloon body. [Effects of the Invention]

[0019] According to the above-described balloon for a balloon catheter, the ratio W1 / H1 of the height H1 of the protruding portion to the width W1 of the protruding portion in the straight tube portion is greater than the ratio W2 / H2 of the height H2 of the protruding portion to the width W2 of the protruding portion in the proximal tapered portion, and therefore the balloon for a balloon catheter can be easily inserted into a body cavity, has good pushability, and can easily incise a stricture portion. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a side view of a balloon catheter according to an embodiment of the present invention. [Figure 2] 2 is a longitudinal sectional view of the balloon catheter shown in FIG. 1 in an expanded state of the balloon. [Figure 3] FIG. 3 shows a cross-sectional view taken along the line III-III in FIG. [Figure 4] 4 shows a cross-sectional view taken along the line IV-IV in FIG. [Figure 5] 10 is a radial cross-sectional view of a straight pipe portion according to another embodiment of the present invention. [Figure 6] 10 is a radial cross-sectional view of a straight pipe portion according to still another embodiment of the present invention. [Figure 7] 10A and 10B illustrate radial cross-sectional views of a proximal taper according to another embodiment of the present invention. [Figure 8] 13A and 13B illustrate radial cross-sectional views of a proximal taper according to yet another embodiment of the present invention. [Figure 9] 13A and 13B illustrate radial cross-sectional views of a proximal taper according to yet another embodiment of the present invention. [Figure 10] FIG. 6 is a diagram illustrating the tip of the protrusion in the embodiment shown in FIG. 5. [Figure 11] 1 shows a plan view of a balloon according to an embodiment of the present invention, viewed from the protruding portion side. [Figure 12] FIG. 10 illustrates a radial cross-section of a distal taper according to one embodiment of the present invention. [Figure 13] 10A and 10B illustrate radial cross-sections of a distal taper according to another embodiment of the present invention. [Figure 14]FIG. 2 illustrates a perspective view of a parison prior to expansion according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0021] The present invention will be described in detail below based on the embodiments. However, the present invention is not limited to the following embodiments, and appropriate modifications can be made within the scope of the spirit described above and below, and all such modifications are within the technical scope of the present invention. For convenience, hatching and component symbols may be omitted in the drawings. In such cases, reference should be made to the specification and other drawings. The dimensions of various components in the drawings may differ from their actual dimensions, as priority is given to aiding understanding of the features of the present invention. In this specification, a balloon for a balloon catheter may be simply referred to as a balloon.

[0022] A balloon catheter balloon according to an embodiment of the present invention has a balloon body having an outer surface and an inner surface, a longitudinal axis direction, a radial direction connecting a centroid of a diagram of the balloon body in an inflated state in a cross section perpendicular to the longitudinal axis and a point on the outer surface, and a circumferential direction along the outer periphery of the balloon body in an inflated state in the radial cross section. The balloon body has a straight tubular section, a proximal tapered section located proximal to the straight tubular section, and a distal tapered section located distal to the straight tubular section. The balloon body has protruding portions at the straight tubular section and the proximal tapered section that protrude radially outward from the outer surface of the balloon body and extend in the longitudinal direction, and the ratio W1 / H1 of the height H1 of the protruding portion at the straight tubular section to the width W1 of the protruding portion is greater than the ratio W2 / H2 of the height H2 of the protruding portion at the proximal tapered section. The definitions of the height and width of the protruding portions are as follows. In the radial cross section, the circumscribed circle C of the balloon body b and the radius of the circumscribed circle C b The circumscribing circle C of the protrusion that shares a center with p The difference between the radius of the protrusion and the radius of the protrusion is the height of the protrusion. In the radial cross section, the circumscribed circle C bThe maximum value of the length of the arc inside the outline of the protrusion among the circumferences of the concentric circles that share the same center as the protrusion is defined as the width of the protrusion.

[0023] The ratio W1 / H1 of the height H1 of the protrusions in the straight tube section to the width W1 of the protrusions is greater than the ratio W2 / H2 of the height H2 of the protrusions in the proximal tapered section to the width W2 of the protrusions, resulting in a balloon that can be incised efficiently during inflation. This is thought to be because, by satisfying the above relationship, the width W1 of the protrusions in the straight tube section can be made larger than the height H1, thereby widening the area that can be incised by the protrusions in the circumferential direction z and increasing the inflation force during incision. Furthermore, a relatively large ratio W1 / H1 of the height H1 of the protrusions in the straight tube section to the width W1, i.e., the height H1 of the protrusions is relatively smaller than the width W1, allows the outer diameter of the balloon to be relatively small when deflated, facilitating insertion of the balloon into the body cavity. Furthermore, the reduced rigidity of the balloon facilitates balloon deflation, shortening deflation time. This shortens treatment time when multiple inflations are performed and shortens the time required to remove the deflated balloon after inflation or transport it to another lesion, resulting in safer treatment with less strain on the patient.

[0024] Furthermore, the ratio W1 / H1 of the height H1 of the protrusions to the width W1 of the protrusions in the straight tube section is greater than the ratio W2 / H2 of the height H2 of the protrusions to the width W2 of the protrusions in the proximal tapered section. This relatively small ratio W2 / H2 of the height H2 of the protrusions to the width W2 of the protrusions in the proximal tapered section allows the height H2 of the protrusions in the proximal tapered section to be greater than the width W2. This increases the bending rigidity of the proximal tapered section compared to the straight tube section, resulting in a balloon with good pushability. Furthermore, the relatively small ratio W2 / H2 of the height H2 of the protrusions to the width W2 of the protrusions in the proximal tapered section, i.e., the width W2 of the protrusions is smaller than the height H2, thereby narrowing the area that creates a steric hindrance when inserting the balloon into a body cavity in the circumferential direction, facilitating insertion of the balloon into a body cavity.

[0025] In this way, the balloon of the present invention can reduce the bending stiffness in the longitudinal direction from the proximal side to the distal side of the balloon, so that the balloon as a whole has an optimal balance of bending stiffness, and has good pushability as well as good kink resistance and insertability.

[0026] A balloon for a balloon catheter will be described with reference to Figures 1 to 14. Figure 1 is a side view of a balloon catheter according to one embodiment of the present invention. Figure 2 is a longitudinal cross-sectional view of the balloon of the balloon catheter shown in Figure 1 in an inflated state. Figure 3 is a cross-sectional view taken along III-III in Figure 1, and Figure 4 is a cross-sectional view taken along IV-IV in Figure 1. Figure 5 is a radial cross-sectional view of a straight tube section according to another embodiment of the present invention, and Figure 6 is a radial cross-sectional view of a straight tube section according to yet another embodiment of the present invention. Figures 7 to 9 are radial cross-sectional views of proximal tapered sections according to different embodiments of the present invention. Figure 10 is a diagram illustrating the tip of the protrusion in the embodiment shown in Figure 5. In Figures 5 to 10, the inner tube and hatching have been omitted to facilitate understanding of the height and width of the protrusion. Figure 11 is a plan view of a balloon according to one embodiment of the present invention, as seen from the protrusion side. Figure 12 is a radial cross-sectional view of a distal tapered section according to one embodiment of the present invention, and Figure 13 is a radial cross-sectional view of a distal tapered section according to another embodiment of the present invention. FIG. 14 depicts a perspective view of a parison prior to expansion according to one embodiment of the present invention.

[0027] In the present invention, the proximal side refers to the direction toward the user or surgeon with respect to the extension direction of the balloon catheter 1 or the longitudinal axis direction x of the shaft 3, and the distal side refers to the opposite side of the proximal side, i.e., the direction toward the treatment target. Even if a member other than a long member such as the shaft 3 has the same longitudinal axis direction x as the shaft 3, it has the same longitudinal axis direction x as the shaft 3.

[0028] As shown in Figures 1 and 2, the balloon catheter 1 has a shaft 3 and a balloon catheter balloon 2 provided on the outside of the shaft 3. The balloon catheter 1 has a distal side and a proximal side, and the balloon 2 is provided on the distal side of the shaft 3. The balloon catheter 1 is configured so that a fluid is supplied to the inside of the balloon 2 through the shaft 3, and the expansion and contraction of the balloon 2 can be controlled using an indeflator (balloon pressurizer). The fluid may be a pressurized fluid pressurized by a pump or the like.

[0029] The shaft 3 preferably has an internal fluid flow path and further has a guidewire insertion path. An example of a configuration in which the shaft 3 has an internal fluid flow path and a guidewire insertion path is a configuration in which the shaft 3 has an outer tube 31 and an inner tube 32, the inner tube 32 functions as a guidewire insertion path, and the space between the inner tube 32 and the outer tube 31 functions as a fluid flow path. In this configuration in which the shaft 3 has the outer tube 31 and the inner tube 32, it is preferable that the inner tube 32 extends from the distal end of the outer tube 31 and penetrates distally of the balloon 2, the distal side of the balloon 2 is joined to the inner tube 32, and the proximal side of the balloon 2 is joined to the outer tube 31.

[0030] As shown in Figures 1 and 2, the balloon 2 has a balloon body 20 with an outer surface and an inner surface, and has a longitudinal axis direction x, a radial direction y connecting the centroid of a diagram outlining the outer shape of the balloon body 20 in an expanded state in a cross section perpendicular to the longitudinal axis direction x and a point on the outer surface, and a circumferential direction z along the outer periphery of the balloon body 20 in an expanded state in the cross section in the radial direction y.

[0031] The balloon body 20 has a straight tube section 23, a proximal tapered section 22 located proximal to the straight tube section 23, and a distal tapered section 24 located distal to the straight tube section 23. The straight tube section 23 preferably has approximately the same diameter in the longitudinal axis direction x, and the proximal tapered section 22 and the distal tapered section 24 are preferably formed so that their diameters decrease with increasing distance from the straight tube section 23. Because the straight tube section 23 has the largest diameter, when the balloon 2 is inflated at a lesion such as a stenosis, the straight tube section 23 can be in sufficient contact with the lesion, facilitating dilation or incision of the lesion. Furthermore, because the proximal tapered section 22 and the distal tapered section 24 have reduced diameters, the outer diameters of the proximal and distal ends of the balloon 2 can be reduced when the balloon 2 is deflated, thereby reducing the step between the shaft 3 and the balloon 2, thereby facilitating insertion of the balloon 2 into a body cavity.

[0032] The balloon 2 may have a non-expandable proximal sleeve portion 21 and a non-expandable distal sleeve portion 25 located proximally of the proximal tapered portion 22 and distally of the distal tapered portion 24, respectively. At least a portion of the proximal sleeve portion 21 and the distal sleeve portion 25 may be fixed to the shaft 3, and in the case where the shaft 3 has an outer tube 31 and an inner tube 32, at least a portion of the proximal sleeve portion 21 may be fixed to the outer tube 31, and at least a portion of the distal sleeve portion 25 may be fixed to the inner tube 32.

[0033] As shown in Figures 2 to 4, the balloon body 20 has protrusions 60 at the straight tube section 23 and the proximal tapered section 22 that protrude radially outward from the outer surface of the balloon body 20 in the y-direction and extend in the x-direction. The maximum length of the protrusions 60 protruding radially outward from the outer surface of the balloon body 20 in the y-direction in a cross section of the y-direction 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. It is also acceptable for the maximum length to be at most 100 times, 50 times, 30 times, or 10 times. This maximum length may also vary along the x-direction. Protrusions 60 with a maximum length within the above range facilitate incisions of appropriate depth in strictures, facilitating incisions. Furthermore, the presence of the protrusions 60 on the balloon body 20 can improve the strength of the balloon 2 and prevent overexpansion of the balloon 2 when pressurized.

[0034] 1 and 2, the protrusion 60 disposed on the proximal tapered section 22 may extend to the proximal sleeve section 21, so that the balloon body 20 also has the protrusion 60 in the proximal sleeve section 21. Alternatively, although not shown, the balloon body 20 may not have the protrusion 60 in the proximal sleeve section 21.

[0035] As shown in Figures 3 and 4, the number of protrusions 60 in the circumferential direction z may be multiple, or as shown in Figures 5 to 9, the number may be one. When multiple protrusions 60 are provided in the circumferential direction z, the multiple protrusions 60 are preferably spaced apart in the circumferential direction z, and more preferably arranged at equal intervals in the circumferential direction z. The separation distance is preferably longer than the maximum circumferential length of the protrusions 60. By arranging the protrusions 60 at intervals in the circumferential direction z, preferably at equal intervals, it becomes easier to fix the balloon 2 and to incise the stricture site.

[0036] The protrusions 60 extending in the longitudinal axis direction x on the outer surface of the balloon body 20 may be arranged at the same position in the circumferential direction z in the longitudinal axis direction x, i.e., straight in the longitudinal axis direction x as shown in FIG. 2. If the protrusions 60 are arranged straight, the stenotic area can be incised in a straight line. Alternatively, although not shown, the protrusions 60 may be arranged at different positions in the circumferential direction z in the longitudinal axis direction x, for example, in a spiral shape that wraps around the outer surface of the balloon body 20 in the circumferential direction z. With such protrusions 60, the stenotic area can be incised obliquely.

[0037] The ratio W1 / H1 of the height H1 of the protrusion 60 to the width W1 of the protrusion 60 in the straight tube section 23 is greater than the ratio W2 / H2 of the height H2 of the protrusion 60 to the width W2 of the protrusion 60 in the proximal tapered section 22. Here, the circumscribing circle C of the balloon body 20 in the cross section in the radial direction y is b radius r b and circumscribed circle C b The circumscribing circle C of the protrusion 60 that shares the center O with p radius r p The difference between the height of the protrusion 60 and the circumscribing circle C b Concentric circles C that share center O with c The maximum length of the arc of the circumference that is inside the outline of the protrusion 60 is defined as the width of the protrusion 60.

[0038] The definition of the height of the protrusion 60 will be explained with reference to Figs. 5 to 9. Fig. 5 is a cross-sectional view of the straight tube portion 23 of the balloon 2 according to one embodiment in the radial direction y. In the embodiment shown in Fig. 5, the outer periphery of the balloon body 20 is circular, so the circumscribing circle C b The circumscribing circle C coincides with the outer periphery of the balloon body 20. b The circumscribing circle C of the protrusion 60 that shares the center O with p is uniquely determined, so the circumscribed circle C p radius r p and circumscribed circle C b radius r b By calculating the difference between these values, the height H1 of the protrusion 60 in the straight pipe section 23 can be obtained.

[0039] 6 is a cross-sectional view of the proximal tapered portion 22 of a balloon 2 according to another embodiment taken along the radial direction y. In the embodiment shown in FIG. 6, the thickness of the balloon body 20 in the circumferential direction z is increased in the portion where the protrusions 60 are arranged, and the outer periphery of the balloon body 20 becomes a substantially ellipse that is elongated only in the direction of the protrusions 60, deviating from a circle. Therefore, the circumscribed circle C b is different from the outer circumference of the balloon body 20. Even in such a case, the circumscribing circle C b The circumscribing circle C of the protrusion 60 that shares the center O with p is uniquely determined, so the circumscribed circle C p radius r p and circumscribed circle C b radius r b The height H1 of the protrusion 60 in the straight tube section 23 can be obtained by calculating the difference between these. The outer periphery of the balloon body 20 may deviate from a circle because the thickness of the balloon body 20 varies in the circumferential direction z in the cross section taken in the radial direction y, as shown in Figure 6. Alternatively, although not shown, the thickness of the balloon body 20 may be the same in the circumferential direction z in the cross section taken in the radial direction y, but the cross-sectional shape of the balloon body 20 itself may deviate from a circle, causing the outer periphery of the balloon body 20 to deviate from a circle.

[0040] 7 is a cross-sectional view of the proximal tapered portion 22 of the balloon 2 according to one embodiment taken along the radial direction y. In the embodiment shown in FIG. 7, the outer periphery of the balloon body 20 is circular, so that the circumscribing circle C b The circumscribing circle C coincides with the outer periphery of the balloon body 20. b The circumscribing circle C of the protrusion 60 that shares the center O with p is uniquely determined, so the circumscribed circle C p radius r p and circumscribed circle C b radius r b By calculating the difference between these two values, the height H2 of the protruding portion 60 in the proximal tapered portion 22 can be obtained. Although not shown, as described above with reference to FIG. 6 in the explanation of the straight tube portion 23, even if the outer periphery of the balloon body 20 deviates from a circle, the circumscribed circle C b and circumscribed circle C p is uniquely determined, so the circumscribed circle C p radius r pand circumscribed circle C b radius r b By calculating the difference between these values, the height H2 of the protruding portion 60 in the proximal tapered portion 22 can be obtained.

[0041] 8 and 9 are cross-sectional views in the radial direction y of the proximal tapered portion 22 of the balloon 2 according to another embodiment. In the embodiments shown in FIGS. 8 and 9, the cross-sectional shape of the protrusion 60 in the radial direction y is different from the cross-sectional shape in the embodiment shown in FIG. 7. However, even in such a case, the circumscribed circle C b and circumscribed circle C p is uniquely determined, so the circumscribed circle C p radius r p and circumscribed circle C b radius r b By calculating the difference between these values, the height H2 of the protruding portion 60 in the proximal tapered portion 22 can be obtained.

[0042] Next, the definition of the width of the protrusion 60 will be explained with reference to Fig. 5 to Fig. 9. As shown in Fig. 5, in the cross section of the straight pipe portion 23 in the radial direction y, the circumscribing circle C b Concentric circles C that share center O with c The maximum length of the arc inside the outline of the protrusion 60 is the width of the protrusion 60. b Concentric circles C that share center O with c There are an infinite number of concentric circles C, but a part of the circumference of the concentric circle C exists inside the outline of the protrusion 60. c Furthermore, the concentric circle C , which has the maximum length of the arc inside the contour of the protrusion 60, is finite. c At least one of the concentric circles C1 and C2 can be determined, and the length of the arc can be calculated as the width W1 of the protruding portion 60 of the straight pipe portion 23. In the embodiment shown in FIG. 5, the width is maximum at the base end side of the protruding portion 60 closest to the center O, and the length of the arc inside the outline of the protruding portion 60 is maximum. c and the circumscribed circle C of the balloon body 20 b The following are consistent:

[0043] In the embodiment shown in FIG. 6, the width of the protrusion 60 is maximum at the base end side closest to the center O, so that the length of the arc inside the contour of the protrusion 60 is maximum. c and the circumscribed circle C of the balloon body 20 b In addition to this example, although not shown, even if the protrusion 60 has the maximum width on a side other than the base end side, the circumscribing circle C b The concentric circle C has a center O and is located inside the contour of the protrusion 60, and the length of the arc of the concentric circle C is the maximum. c Since at least one of the above can be determined, the width W1 of the protruding portion 60 in the straight pipe portion 23 can be obtained.

[0044] The width W2 of the protruding portion 60 in the proximal tapered portion 22 can be obtained in the same manner as the width W1 of the protruding portion 60 in the straight pipe portion 23. In the embodiments shown in Figs. 7 and 8, the cross-sectional shapes of the protruding portion 60 in the cross section in the radial direction y are different, but the width W2 of the protruding portion 60 can be obtained in the same manner as in the case of the straight pipe portion 23 shown in Fig. 5. In the embodiments shown in Figs. 7 and 8, the protruding portion 60 has the maximum width on the base end side closest to the center O, and the length of the arc inside the outline of the protruding portion 60 is the maximum on the concentric circle C, as in the case of Fig. 5. c and the circumscribed circle C of the balloon body 20 b The following are consistent:

[0045] 9 is an example in which the protrusion 60 has the maximum width on a side other than the base end side. In this case, the concentric circle C c is the circumscribed circle C of the balloon body 20 b Apart from the above, the concentric circle C 1 having the maximum length of the arc inside the contour of the protrusion 60 c Since at least one of the above can be determined, the width W2 of the protrusion 60 can be obtained.

[0046] The shape of the protrusion 60 in a cross section in the radial direction b may be any shape, for example, a substantially triangular shape as shown in Figures 3 to 7, a substantially pentagonal shape as shown in Figures 8 and 9, or a polygonal shape, fan shape, wedge shape, convex shape, spindle shape, circle, etc. Whatever the shape of the protrusion 60 in a cross section in the radial direction y, the height and width of the protrusion 60 can be determined by the above definitions.

[0047] Because the ratio W1 / H1 of the height H1 of the protrusion 60 to the width W1 of the protrusion 60 in the straight tube section 23 determined as described above is greater than the ratio W2 / H2 of the height H2 of the protrusion 60 to the width W2 of the protrusion 60 in the proximal tapered section 22, the width W1 of the protrusion in the straight tube section 23 can be made larger than the height H1, thereby widening the area that can be incised by the protrusion 60 in the circumferential direction z and resulting in a balloon that can be efficiently incised during inflation. Furthermore, because the ratio W1 / H1 of the height H1 of the protrusion 60 to the width W1 in the straight tube section 23 is relatively large, i.e., the height H1 of the protrusion 60 in the straight tube section 23 is relatively small compared to the width W1, the outer diameter of the balloon 2 when deflated can be made relatively small, facilitating insertion of the balloon 2 into a body cavity. In addition, the reduced rigidity of the balloon 2 makes it easier to deflate the balloon 2, shortening the deflation time. This shortens the treatment time when multiple inflations are required, and also shortens the time required to remove the deflated balloon after inflation or transport it to another lesion, allowing for safer treatment with less strain on the patient.

[0048] The ratio W1 / H1 of the height H1 of the protrusion 60 to the width W1 of the protrusion 60 in the straight tube section 23 is greater than the ratio W2 / H2 of the height H2 of the protrusion 60 to the width W2 of the protrusion 60 in the proximal tapered section 22. In other words, the ratio W2 / H2 of the height H2 of the protrusion 60 to the width W2 of the protrusion 60 in the proximal tapered section 22 is relatively small, so that the height H2 of the protrusion 60 in the proximal tapered section 22 can be made larger than the width W2. This makes the bending rigidity of the proximal tapered section 22 in the longitudinal axis direction x greater than that of the straight tube section 23, resulting in a balloon 2 with good pushability. Furthermore, the ratio W2 / H2 of the height H2 to the width W2 of the protrusion 60 in the proximal tapered portion 22 is relatively small, i.e., the width W2 of the protrusion 60 is relatively small compared to the height H2, so that the area that causes a three-dimensional obstacle when inserting the balloon 2 into the body cavity can be narrowed in the circumferential direction z, making it easier to insert the balloon 2 into the body cavity.

[0049] In this way, the bending stiffness of the balloon 2 in the longitudinal axis direction x can be reduced from the proximal side to the distal side of the balloon 2, so that the balloon as a whole has an optimal balance of bending stiffness, good pushability, and good kink resistance and insertability.

[0050] The width W1 of the protruding portion 60 in the straight tube section 23 is preferably wider than the width W2 of the protruding portion in the proximal tapered section 22. Because the width W1 of the protruding portion 60 in the straight tube section 23 is relatively wider, the area that can be incised by the protruding portion 60 of the straight tube section 23 is wider in the circumferential direction z, increasing the expansion force during incision and making it easier to create a balloon 2 that can be incised efficiently. In addition, because the width W2 of the protruding portion 60 in the proximal tapered section 22 is relatively narrow, the area that causes a steric hindrance when inserting the balloon 2 into a body cavity can be narrowed in the circumferential direction z, making it easier to insert the balloon 2 into a body cavity.

[0051] The ratio W1 / H1 in the straight pipe portion 23 is preferably 0.2 or more and 5 or less. The ratio W1 / H1 in the straight pipe portion 23 may be 0.4 or more, 0.6 or more, 0.8 or more, 0.9 or more, 1.0 or more, 1.2 or more, 1.25 or more, 1.3 or more, 1.5 or more, or 2 or more. The ratio W1 / H1 in the straight pipe portion 23 may also be 4 or less, 3.5 or less, or 3 or less.

[0052] The ratio W2 / H2 in the proximal tapered portion 22 is preferably 0.2 or more and 5 or less. The ratio W2 / H2 in the proximal tapered portion 22 may be 0.3 or more, 0.4 or more, 0.5 or more, or 0.8 or more. The ratio W2 / H2 in the proximal tapered portion 22 may also be 3 or less, 2 or less, 1.5 or less, 1.2 or less, or 1.1 or less, more preferably 1.0 or less, and even more preferably 0.9 or less.

[0053] By satisfying the requirement that the ratio W1 / H1 in the straight tube section 23 be greater than the ratio W2 / H2 in the proximal tapered section 22, and by having the ratio W1 / H1 in the straight tube section 23 and the ratio W2 / H2 in the proximal tapered section 22 each have values ​​within the above ranges, the efficiency of the incision, pushability, and insertability within the body cavity can be further improved.

[0054] As shown in FIG. 10, in the cross section in the radial direction y, the protruding portion 60 of the straight pipe portion 23 has a tip end 61, and the width W T and the width W1 of the protrusion 60 T The width W of the tip portion 61 is preferably 0.5 or less. T is the circumscribed circle C in the cross section of the radial direction y. p and the circumscribing circle C, which shares the same center O p radius r p Circle C with a radius of 95% of T The width W of the tip 61 is defined as the length of the arc of the circumference of the tip 61 that is inside the outline of the protrusion 60. T and the width W1 of the protrusion 60 T / W1 is more preferably 0.4 or less, even more preferably 0.3 or less, particularly preferably 0.25 or less, and may be 0.2 or less, or may be 0.1 or less. T and the width W1 of the protrusion 60 T The lower limit of the width W of the tip 61 of the protrusion 60 is not particularly limited, but may be, for example, 0.01. T Since has a value within the above range, when the balloon 2 is expanded at the lesion site and the straight tube portion 23 comes into contact with the narrowed portion, the area of ​​the tip portion 61 of the protrusion 60 coming into contact with the narrowed portion becomes small, allowing a large force to be applied to a small area, thereby increasing the stress at the narrowed portion and making it easier to incise the narrowed portion.

[0055] While satisfying the requirement that the ratio W1 / H1 in the straight tube section 23 be greater than the ratio W2 / H2 in the proximal tapered section 22, the height H1 of the protruding portion 60 of the straight tube section 23 is preferably at least 0.1 mm. The height H1 of the protruding portion 60 of the straight tube section 23 is more preferably 0.2 mm or greater, even more preferably 0.3 mm or greater, and particularly preferably 0.4 mm or greater. If the height H1 of the protruding portion 60 of the straight tube section 23 is equal to or greater than the above value, when the balloon 2 is inflated at the lesion and the straight tube section 23 abuts against the stenosis, the stress applied to the stenosis by the tip 61 of the protruding portion 60 can be increased, making it easier to incise the stenosis. Furthermore, the height H1 of the protruding portion 60 of the straight tube section 23 is preferably 1 mm or less, more preferably 0.8 mm or less, even more preferably 0.7 mm or less, and particularly preferably 0.6 mm or less. If the height H1 of the protruding portion 60 of the straight tube portion 23 is equal to or less than the above value, the balloon 2 can be easily inserted into the body cavity when being transported to the affected area.

[0056] Because the effect of the height H1 of the protruding portion 60 of the straight tube portion 23 on the stress on the stenotic portion saturates above the upper limit, there is no need to increase the height H1 of the protruding portion 60 of the straight tube portion 23 beyond the upper limit. By satisfying the requirement that the ratio W1 / H1 in the straight tube portion 23 be greater than the ratio W2 / H2 in the proximal tapered portion 22, the stress applied to the stenotic portion by the protruding portion 60 of the straight tube portion 23 can be ensured over a wide range in the circumferential direction z, thereby providing a balloon 2 that can perform efficient incision while maintaining good insertability without increasing the height H1 of the protruding portion 60 of the straight tube portion 23 more than necessary.

[0057] The height T2 of the protruding portion 60 in the proximal tapered portion 22 is preferably greater than the height T1 of the protruding portion 60 in the straight tube portion 23. This improves the bending rigidity in the longitudinal axis direction x in the proximal tapered portion 22, resulting in good pushability, while reducing the rigidity in the straight tube portion 23, facilitating deflation of the balloon 2 and facilitating insertion of the balloon 2 into a body cavity. However, it is important that the above relationship between the height T2 of the protruding portion in the proximal tapered portion 22 and the height T1 of the protruding portion 60 in the straight tube portion 23 satisfies the requirement that the ratio W1 / H1 in the straight tube portion 23 is greater than the ratio W2 / H2 in the proximal tapered portion 22. By satisfying this requirement, the balloon 2 can be made to have good pushability, be easily inserted into a body cavity, and efficiently incise a stricture.

[0058] As shown in Figure 10, in a cross section in the radial direction y, the protruding portion 60 of the straight pipe portion 23 has a tip portion 61, and the tip portion 61 preferably has an angle θ of 135° or less. The angle θ is more preferably 120° or less, even more preferably 100° or less, and may be 90° or less, 80° or less, 60° or less, or 30° or less. The angle θ is preferably 5° or more, preferably 10° or more, and even more preferably 20° or more. If the angle θ is within the above range, efficient incision is possible.

[0059] 11, it is preferable that the protruding portion 60 of the straight tube portion 23 and the protruding portion 60 of the proximal tapered portion 22 extend continuously in the longitudinal axis direction x. By having the protruding portion 60 extend continuously in the longitudinal axis direction x from the proximal tapered portion 22 to the straight tube portion 23, it is possible to improve the rigidity of the balloon 2 and prevent the balloon 2 from overexpanding when pressurized, thereby further improving pushability.

[0060] 12, the distal tapered portion 24 may have a protrusion 60, and the height H3 of the protrusion 60 of the distal tapered portion 24 is preferably less than the height H1 of the protrusion 60 of the straight tube portion 23. Because the distal tapered portion 24 is the leading portion when the balloon 2 is inserted into a body cavity, reducing the height H3 of the protrusion of the distal tapered portion 24 reduces the outer diameter of the distal tapered portion 24, thereby facilitating insertion of the balloon 2 into a body cavity. In the distal tapered portion 24, the protrusion 60 may be disposed over a portion of or the entire distance from the proximal end to the distal end of the distal tapered portion 24 in the longitudinal axis direction x. To facilitate insertion of the balloon 2 into a body cavity, it is preferable that the protrusion 60 is located on a portion of the distal tapered section 24 in the longitudinal direction x, and in this case, it is preferable that the protrusion 60 is located on the proximal end side of the distal tapered section 24, and that no protrusion 60 is located on the distal end side of the distal tapered section 24. This allows the outer diameter of the distal end side of the distal tapered section 24 to be reduced, thereby making it easier to insert the balloon 2 into a body cavity.

[0061] The distal tapered section 24 may have one or more protrusions 60, similar to the proximal tapered section 22 and the straight tube section 23. The protrusions 60 of the straight tube section 23 and the protrusions of the distal tapered section 24 preferably extend continuously in the longitudinal axis direction x. By having the protrusions 60 extend continuously in the longitudinal axis direction x from the straight tube section 23 to the distal tapered section 24, it is possible to improve the rigidity of the balloon 2 and suppress overexpansion of the balloon 2 when pressurized, thereby further improving pushability.

[0062] As shown in FIG. 13 , the distal tapered portion 24 preferably includes an inner protrusion 70 that protrudes radially inward from the inner surface of the balloon body 20 and extends in the longitudinal direction x. With this configuration, even if the height H3 of the protrusion 60 in the distal tapered portion 24 is low, the inner protrusion 70 can reinforce the balloon body 20 from the inside, improving the rigidity of the distal tapered portion 24 and preventing overexpansion of the balloon 2 when pressurized, thereby further improving pushability. Although FIG. 13 shows an embodiment including both the inner protrusion 70 and the protrusion 60, if the distal tapered portion 24 includes the inner protrusion 70, the distal tapered portion 24 does not necessarily have to include the protrusion 60. Even if the distal tapered portion 24 does not include the protrusion 60, the presence of the inner protrusion 70 can improve the rigidity of the distal tapered portion 24 and prevent overexpansion of the balloon 2 when pressurized.

[0063] 13, the distal tapered portion 24 has a protruding portion 60 and an inner protruding portion 70, and the protruding portion 60 and the inner protruding portion 70 of the distal tapered portion 24 are preferably located at the same position in the circumferential direction z. The protruding portion 60, which can reinforce the balloon body 20 from the outside, and the inner protruding portion 70, which can reinforce the balloon body 20 from the inside, can reinforce the balloon body 20 at the same position in the circumferential direction z in the distal tapered portion 24, thereby further preventing over-expansion of the balloon 2 when pressurized.

[0064] Examples of materials for the balloon body 20 include polyolefin resins such as polyethylene, polypropylene, and ethylene-propylene copolymer; polyester resins such as polyethylene terephthalate and polyester elastomer; polyurethane resins such as polyurethane and polyurethane elastomer; polyphenylene sulfide resins; polyamide resins such as polyamide and polyamide elastomer; fluorine-containing resins; silicone resins; and natural rubbers such as latex rubber. These materials may be used alone or in combination. Among these, polyamide resins, polyester resins, and polyurethane resins are preferred. Elastomer resins are particularly preferred for achieving thinness and flexibility in the balloon body 20. Among polyamide resins, nylon 12 and nylon 11 are preferred, with nylon 12 being more preferred due to its ease of blow molding. Furthermore, polyamide elastomers such as polyetheresteramide elastomers and polyamideether elastomers are preferred for achieving thinness and flexibility in the balloon body 20. Among these, polyether ester amide elastomers are preferably used because they have high yield strength and provide good dimensional stability to the balloon body 20 .

[0065] The protrusions 60 are preferably made of the same material as the balloon body 20. If the protrusions 60 are made of the same material as the balloon body 20, the flexibility of the balloon 2 can be maintained while the protrusions 60 are less likely to damage the outer surface of the balloon body 20. The balloon body 20 and the protrusions 60 are preferably molded integrally. This prevents the protrusions 60 from falling off the balloon body 20.

[0066] In an embodiment in which the inner protrusion 70 is formed on the distal tapered section 24, it is preferable that the inner protrusion 70 is also made of the same material as the balloon body 20 for the same reasons as above.

[0067] The balloon 2 can be manufactured by, for example, placing a parison 200 made of resin and having a thick-walled portion 220 extending in the longitudinal axis direction x along at least a portion of the circumferential direction z in a mold having a groove in its inner cavity, as shown in Figure 14, and performing biaxial stretch blow molding. The protruding portion 60 can be formed, for example, by inserting the parison 200 into the inner cavity of the mold, causing the thick-walled portion 220 of the parison 200 to fit into the groove in the mold, and introducing a fluid into the inner cavity 210 of the parison 200 to inflate the parison 200. The width and height of the protruding portion 60 can be adjusted by changing the thickness of the thick-walled portion 220 of the parison 200 and the depth and shape of the groove in the mold. Furthermore, the distal tapered portion 24 having the inward protrusion 70 can be formed, for example, by pressing the thick-walled portion 220 of the parison 200 corresponding to the distal tapered portion 24 against a portion of the mold with shallow or no grooves, and introducing a fluid into the lumen 210 of the parison 200 to expand the parison 200. When a mold with shallow grooves in that portion is used, the protrusion 60 and the inward protrusion 70 can be arranged at the same position in the circumferential direction z. When a mold with no grooves in that portion is used, the inward protrusion 70 can be formed without the protrusion 60. The materials constituting the balloon body 20 can be used as the material for the parison 200.

[0068] Examples of materials that can be used to form the shaft 3 include polyamide resins, polyester resins, polyurethane resins, polyolefin resins, fluorine-based resins, vinyl chloride resins, silicone resins, and natural rubber. These materials can be used alone or in combination. Among these, the material that forms the shaft 3 is preferably at least one of polyamide resins, polyolefin resins, and fluorine-based resins. This can increase the slipperiness of the surface of the shaft 3 and improve the insertability of the balloon catheter 1 within a body cavity.

[0069] The balloon 2 and the shaft 3 can be joined by adhesive bonding, welding, or by attaching a ring-shaped member to the overlapping portion of the end of the balloon 2 and the shaft 3 and crimping them. Among these, it is preferable that the balloon 2 and the shaft 3 are joined by welding. By welding the balloon 2 and the shaft 3, the bond between the balloon 2 and the shaft 3 is unlikely to come loose even when the balloon 2 is repeatedly expanded and contracted, and the bond strength between the balloon 2 and the shaft 3 can be easily increased.

[0070] As shown in FIG. 1 , balloon catheter 1 may include a hub 4 on the proximal side of shaft 3. Hub 4 may include a fluid injection section 7 that communicates with a fluid flow path for supplying fluid to the interior of balloon 2. Hub 4 preferably includes a guidewire insertion section 5 that communicates with a guidewire insertion passage. By including hub 4 with fluid injection section 7 and guidewire insertion section 5, balloon catheter 1 can easily inflate balloon 2 by supplying fluid to the interior of balloon 2 and deliver balloon 2 to a treatment site along the guidewire. In addition to so-called over-the-wire balloon catheters in which a guidewire is inserted from the distal side to the proximal side of shaft 3 as shown in FIG. 1 , balloon 2 according to embodiments of the present invention can also be applied to so-called rapid exchange balloon catheters in which a guidewire is inserted partway from the distal side to the proximal side of the shaft.

[0071] The shaft 3 and the hub 4 can be joined by, for example, bonding with an adhesive or welding. Of these, it is preferable that the shaft 3 and the hub 4 are joined by adhesive. By bonding the shaft 3 and the hub 4, the bond strength between the shaft 3 and the hub 4 can be increased, thereby improving the durability of the balloon catheter 1, even when the shaft 3 and the hub 4 are made of different materials, such as when the shaft 3 is made of a highly flexible material and the hub 4 is made of a highly rigid material.

[0072] This application claims the benefit of priority to Japanese Patent Application No. 2021-41378, filed on March 15, 2021. The entire contents of the specification of Japanese Patent Application No. 2021-41378, filed on March 15, 2021, are incorporated herein by reference. [Explanation of symbols]

[0073] 1: Balloon catheter 2: Balloon 3: Shaft 4: Hub 5: Guidewire insertion section 7:Fluid injection part 20: Balloon body 21: Proximal sleeve part 22: Proximal tapered section 23: Straight pipe section 24: Distal tapered section 25: Distal sleeve 31: Outer tube 32: Inner tube 60:Protrusion 61:Tip 70: Inner protrusion 200:Parison 210: Lumen of parison 220: Thick part of parison C b : circumscribed circle of the balloon body r b : Radius of the circumscribed circle of the balloon body H1: Height of protrusion in straight pipe section H2: Height of the protruding part at the proximal taper H3: Height of the protrusion at the distal taper W1: Width of the protrusion in the straight pipe section W2: Width of the protruding part at the proximal taper W T :Width of the tip of the protrusion in the straight pipe section x: longitudinal axis direction y: radial direction z: Circumferential direction

Claims

1. a balloon body having an outer surface and an inner surface; a longitudinal axis direction, a radial direction connecting a centroid of a diagram outlining the outer shape of the balloon body in an expanded state in a cross section perpendicular to the longitudinal axis direction and a point on the outer surface, and a circumferential direction along the outer periphery of the balloon body in an expanded state in the cross section in the radial direction, the balloon body has a straight tube portion, a proximal tapered portion located proximally of the straight tube portion, and a distal tapered portion located distally of the straight tube portion; the balloon body has protruding portions at the straight tube portion, the proximal tapered portion, and the distal tapered portion, the protruding portions protruding radially outward beyond the outer surface of the balloon body and extending in the longitudinal axis direction; The height H of the protrusion in the straight pipe section １ and the width W of the protrusion １ Ratio of W １ / H １ is the height H of the protrusion at the proximal tapered portion ２ and the width W of the protrusion ２ Ratio of W ２ / H ２ is larger than A balloon for a balloon catheter, wherein a height H 3 of the protruding portion of the distal tapered portion is lower than a height H 1 of the protruding portion of the straight tube portion. (Here, the definitions of the height and width of the protrusion are as follows: In the radial cross section, the circumscribing circle C of the balloon body ｂ and the radius of the circumscribed circle C ｂ The circumscribing circle C of the protrusion that shares a center with ｐ The difference between the radius of the protrusion and the radius of the protrusion is the height of the protrusion. In the radial cross section, the circumscribing circle C ｂ The maximum value of the length of the arc inside the outline of the protrusion among the circumferences of the concentric circles sharing the same center with is the width of the protrusion.)

2. The width W of the protrusion in the straight pipe section １ is the width W of the protrusion at the proximal tapered portion ２ 2. The balloon for a balloon catheter according to claim 1, wherein the balloon is wider than the

3. The ratio W １ / H １ 3. The balloon for a balloon catheter according to claim 1, wherein the value of the saturation coefficient is 0.2 or more and 5 or less.

4. The ratio W ２ / H ２ The balloon for a balloon catheter according to any one of claims 1 to 3, wherein is 0.2 or more and 5 or less.

5. In the radial cross section, the protruding portion of the straight pipe portion has a tip end, and the width W of the tip end of the protruding portion Ｔ and the width W of the protrusion １ Ratio to W Ｔ / W １ The balloon for a balloon catheter according to any one of claims 1 to 4, wherein is 0.5 or less. (Here, the width of the tip of the protrusion is defined as follows: In the radial cross section, the circumscribing circle C ｐ A concentric circle that shares a center with the circumscribing circle C ｐ The width of the tip is the length of the arc inside the outline of the protrusion on the circumference of a circle whose radius is 95% of the radius of the tip.)

6. The height H of the protruding portion of the straight pipe portion １ The balloon for a balloon catheter according to any one of claims 1 to 5, wherein the thickness of the balloon is at least 0.1 mm or more.

7. 7. The balloon for a balloon catheter according to claim 1, wherein the protruding portion of the straight tube portion has a tip end at an angle of 135° or less in the radial cross section.

8. 8. The balloon for a balloon catheter according to claim 1, wherein the protruding portion of the straight tube section and the protruding portion of the proximal tapered section extend continuously in the longitudinal axis direction.

9. 9. The balloon for a balloon catheter according to claim 1, wherein the protrusion of the straight tube section and the protrusion of the distal tapered section extend continuously in the longitudinal axis direction.

10. 10. The balloon for a balloon catheter according to claim 1, wherein the distal tapered portion has an inward protruding portion that protrudes radially inward beyond the inner surface of the balloon body and extends in the longitudinal axis direction.

11. A balloon for a balloon catheter as described in Claim 10, wherein the protrusion and the inner protrusion of the distal tapered portion are arranged at the same position in the circumferential direction.

12. The balloon for a balloon catheter according to any one of claims 1 to 11, wherein the protrusions are made of the same material as the balloon body.

Images