Balloon catheter

Abstract

To provide a balloon catheter that is less prone to balloon displacement and can accurately apply pressure to the target area. [Solution] A balloon catheter 1 comprises a balloon group 11 including a plurality of balloons 10 arranged in parallel with each other in the circumferential direction z, and a covering material 100 arranged radially outward in the y direction of the balloon group 11, wherein the balloon group 11 has a central region 121 including a midpoint P3 in the longitudinal direction x, a distal region 122 located distal to the central region 121, and a proximal region 123 located proximal to the central region 121, the covering material 100 is arranged in the central region 121, the tensile stress of the covering material 100 is higher than the tensile stress of the balloon membrane of the balloons 10, and in the expanded state of the balloon group 11, the minimum outer diameter D121 in the central region 121 is smaller than the maximum outer diameter D122 in the distal region 122 and the maximum outer diameter D123 in the proximal region 123.

Description

Technical Field

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

Background Art

[0002] When a stenosis hardened by calcification or the like is formed on the inner wall of a blood vessel, diseases such as angina pectoris and myocardial infarction are caused. As one of the treatments for these, there is an angioplasty in which a stenosis is expanded using a balloon catheter. Angioplasty is a minimally invasive treatment that does not require a thoracotomy such as bypass surgery and is widely performed.

[0003] There is a disease called aortic valve stenosis in which the aortic valve becomes hard due to calcification or the like, the aortic valve becomes difficult to open, and blood flow is obstructed. As a treatment for aortic valve stenosis, a method of surgically opening the chest and placing a biological valve (artificial valve) by catheter to replace the hardened aortic valve may be used.

[0004] The implanted biological valve deteriorates over time due to calcification, wear, etc. When the implanted biological valve deteriorates, it is necessary to replace the biological valve. In replacing the biological valve, a technique has been studied in which a plurality of balloon catheters are used to apply high pressure to the implanted biological valve to deform or break it, expand the lumen of the valve, and then implant a new biological valve inside the deformed or broken biological valve by transcatheter aortic valve replacement or the like.

[0005] As balloon catheters used for dilating hardened stenoses or implanting bioprosthetic valves, for example, Patent Document 1 discloses a catheter having an inflation means consisting of a plurality of inflation elements, characterized in that the walls of the plurality of inflation elements come together to form a substantially circular cross-section when the inflation means is inflated; Patent Document 2 discloses a balloon catheter having a plurality of balloon members, wherein a plurality of outer balloon members are arranged to surround the outer surface of an inner balloon member; Patent Document 3 discloses a balloon catheter having a plurality of balloons, which expand independently without being affected by other balloons, and which are separated from other balloons in the expanded state and do not come into contact with each other; Patent Document 4 discloses a device having a perfusion balloon having an internal passage and a balloon arranged in the internal passage of the perfusion balloon; and Patent Document 5 discloses a catheter including first to third balloons that can be inflated and deflated independently of each other. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Special Publication No. 03-013907 [Patent Document 2] U.S. Patent Application Publication No. 2012 / 0209375 Specification [Patent Document 3] Japanese Patent Publication No. 2018-175550 [Patent Document 4] Special Publication No. 2018-536474 [Patent Document 5] International Publication No. 2021 / 054189 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] However, with the conventional balloon catheters described above, when multiple balloons are inflated to dilate a stenotic area or deform or destroy an implanted bioprosthetic valve, the balloons may move within the bioprosthetic lumen, causing displacement. This makes it difficult and time-consuming to adequately dilate the stenotic area or deform or destroy the bioprosthetic valve.

[0008] In view of the above circumstances, the present invention aims to provide a balloon catheter that is less prone to balloon displacement and can accurately apply pressure to the target location. [Means for solving the problem]

[0009] A balloon catheter according to an embodiment of the present invention that can solve the above problems is as follows. [1] A group of balloons including multiple balloons arranged in parallel to each other in the circumferential direction, A balloon catheter having a covering material arranged radially outward of the balloon group, The balloon group has a central region including the midpoint in the longitudinal direction, a distal region located distal to the central region, and a proximal region located proximal to the central region. The covering material is arranged in the central region, The tensile stress of the coating material is higher than the tensile stress of the balloon membrane of the balloon. In the expanded state of the balloon group, the minimum outer diameter of the balloon catheter in the central region is smaller than the maximum outer diameter of the balloon catheter in the distal region and the maximum outer diameter of the balloon catheter in the proximal region. [2] The covering material is the balloon catheter described in [1], which is positioned at the midpoint. [3] The balloon catheter according to [1] or [2], wherein the coefficient of friction of the covering material is greater than the coefficient of friction of the balloon membrane. [4] The balloon catheter according to any one of [1] to [3], wherein the covering material is not provided in the distal region and the proximal region. [5] The balloon catheter according to any one of [1] to [4], wherein the covering material is a tubular body having the property of shrinking at least radially when heat is applied. [6] The balloon catheter according to any one of [1] to [5], wherein the covering material comprises fibers or wires. [7] The balloon catheter according to any one of [1] to [6], wherein the covering material comprises a film-like material. [8] The balloon catheter according to any one of [1] to [7], wherein the balloon group comprises an inner balloon and a plurality of outer balloons arranged radially outward of the inner balloon. [9] It further has a shaft that has a longitudinal direction, The balloon catheter according to any one of [1] to [8], wherein the internal balloons are arranged in multiple locations at different positions along the longitudinal direction of the shaft. [Effects of the Invention]

[0010] According to the balloon catheter described above, the covering material is positioned in the central region of the balloon group, and the minimum outer diameter of the balloon catheter in the central region is smaller than the maximum outer diameter of the balloon catheter in the distal region and the maximum outer diameter of the balloon catheter in the proximal region. As a result, the central region of the balloon group becomes concave when the balloon group is expanded. Therefore, this concave portion of the balloon can hold stenoses or bioprosthetic valves, making it less likely for the balloon to shift position. [Brief explanation of the drawing]

[0011] [Figure 1] This diagram shows an overall view of a balloon catheter according to one embodiment of the present invention. [Figure 2] Figure 1 shows a magnified view of the balloon portion of the balloon catheter. [Figure 3] This shows a cross-sectional view (III-III) of the balloon catheter shown in Figure 1. [Figure 4] Figure 1 shows a cross-sectional view of the balloon catheter from point IV to point IV. [Figure 5] It represents an enlarged view of a portion where the balloon of the balloon catheter according to another embodiment of the present invention is disposed.

Embodiments for Carrying out the Invention

[0012] Hereinafter, the present invention will be described based on embodiments. However, the present invention is not limited by the following embodiments, and it is of course possible to appropriately modify and implement it within a range that conforms to the gist of the foregoing and following descriptions, and all of them are included in the technical scope of the present invention. In each drawing, for convenience, hatching, reference numerals of members, etc. may be omitted, but in such a case, reference shall be made to the specification and other drawings. Also, the dimensions of various members in the drawings may differ from the actual dimensions because priority is given to facilitating the understanding of the features of the present invention.

[0013] The balloon catheter according to an embodiment of the present invention is a balloon catheter having a balloon group including a plurality of balloons arranged in parallel with each other in the circumferential direction, and a covering material disposed radially outward of the balloon group. The balloon group has a central region including a midpoint in the longitudinal direction, a distal region located more distally than the central region, and a proximal region located more proximally than the central region. The covering material is disposed in the central region, and the elongation stress of the covering material is higher than the elongation stress of the balloon film of the balloon. In the expanded state of the balloon group, the minimum outer diameter of the balloon catheter in the central region is smaller than the maximum outer diameter of the balloon catheter in the distal region and the maximum outer diameter of the balloon catheter in the proximal region.

[0014] Hereinafter, a balloon catheter according to an embodiment of the present invention will be described with reference to FIGS. 1 to 5. FIG. 1 is an overall view of a balloon catheter according to an embodiment of the present invention, and FIG. 2 is an enlarged view of a portion where a balloon of the balloon catheter shown in FIG. 1 is disposed. FIG. 3 is a cross-sectional view taken along line III-III of the balloon catheter shown in FIG. 1, representing a cross-sectional view perpendicular to the longitudinal direction of the central region in a portion where a balloon group exists, and FIG. 4 is a cross-sectional view taken along line IV-IV of the balloon catheter shown in FIG. 1, representing a cross-sectional view perpendicular to the longitudinal direction of the distal region in a portion where a balloon group exists. FIG. 5 is an enlarged view of a portion where a balloon of a balloon catheter according to another embodiment of the present invention is disposed.

[0015] As shown in FIGS. 1 to 5, the balloon catheter 1 includes a balloon group 11 including a plurality of balloons 10 arranged in parallel with each other in the circumferential direction z, and a covering material 100 disposed radially outward of the balloon group 11.

[0016] The balloon 10 has a longitudinal direction x, a radial direction y connecting the centroid of the outer edge of the balloon 10 and a point on the outer edge in a cross-section perpendicular to the longitudinal direction x, and a circumferential direction z along the outer edge of the balloon 10 in a cross-section perpendicular to the longitudinal direction x. In this specification, the direction on the user's hand side in the longitudinal direction x is referred to as the proximal side, and the direction opposite to the proximal side, that is, the direction on the side of the treatment target person is referred to as the distal side. Further, when each member or each part is bisected in the longitudinal direction x of the balloon 10, the portion located on the distal side of each member or each part is referred to as the distal part of each member or each part, and the portion located on the proximal side of each member or each part is referred to as the proximal part of each member or each part. The distal end of each member or each part is the end located on the most distal side of each member or each part. The proximal end of each member or each part is the end located on the most proximal side of each member or each part. The end portion includes the peripheral portion of the end. That is, the distal end portion refers to the distal end and the peripheral portion of the distal end, and the proximal end portion refers to the proximal end and the peripheral portion of the proximal end.

[0017] Other components and parts besides the balloon 10 also have longitudinal, radial, and circumferential directions, which may or may not be the same as the longitudinal x, radial y, and circumferential z directions of the balloon 10. However, for the sake of clarity, in this specification, all components and parts are described as having the same longitudinal x, radial y, and circumferential directions as the balloon 10.

[0018] A balloon group 11 having multiple balloons 10 is located distal to the balloon catheter 1. The balloons 10 can be expanded by introducing fluid into their lumen, and the balloons 10 can be deflated by expelling fluid from their lumen. To control the expansion and contraction of the balloons 10, an indeflerator (balloon pressurizer) can be used to introduce or expel fluid. The fluid can be, for example, physiological saline or a mixture of contrast agent and physiological saline. The fluid may also be a pressurized fluid pressurized by a pump or the like.

[0019] Examples of materials that make up the balloon 10 include polyamide resins such as nylon 11 and nylon 12, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polyurethane resins, and thermoplastic elastomers such as polyether block amide copolymers.

[0020] As shown in Figure 2, it is preferable that the balloons 10 constituting the balloon group 11 have a straight tube portion 111, a distal tapered portion 112 located distal to the straight tube portion 111, and a proximal tapered portion 113 located proximal to the straight tube portion 111. It is also preferable that, because the balloon 10 has a straight tube portion 111, a distal tapered portion 112, and a proximal tapered portion 113, the balloon group 11 also has a straight tube portion, a distal tapered portion located distal to the straight tube portion, and a proximal tapered portion located proximal to the straight tube portion.

[0021] The straight section 111 is preferably substantially cylindrical in shape, having approximately the same diameter in the longitudinal direction x, but may have different diameters in the longitudinal direction x. The distal tapered section 112 and the proximal tapered section 113 are preferably formed in a substantially conical or frustoconical shape, decreasing in diameter as they move away from the straight section 111. The straight section 111 has the maximum diameter, so that when the balloon group 11 is expanded in a lesion such as a stenosis, the straight section of the balloons 10 constituting the balloon group 11 can sufficiently contact the lesion, making it easier to perform treatment such as dilation of the lesion. Furthermore, because the distal tapered section 112 and the proximal tapered section 113 are reduced in diameter, when the balloon group 11 is deflated, the outer diameters of the proximal and distal ends of the balloons 10 constituting the balloon group 11 can be reduced, making it easier to insert the balloon catheter 1 into the body cavity.

[0022] Preferably, the balloon 10 constituting the balloon group 11 further includes a distal sleeve portion 114 located distal to the distal tapered portion 112, and a proximal sleeve portion 115 located proximal to the proximal tapered portion 113. In the balloon 10, while the straight tube portion 111, distal tapered portion 112, and proximal tapered portion 113 are parts that expand when fluid is introduced into the balloon 10, it is preferable that the distal sleeve portion 114 and proximal sleeve portion 115 do not expand. By preventing the distal sleeve portion 114 and proximal sleeve portion 115 from expanding, it is possible to easily fix at least a part of the distal sleeve portion 114 and at least a part of the proximal sleeve portion 115 to another object such as the shaft 70 of the balloon catheter 1. Details of the shaft 70 will be described later.

[0023] As shown in Figure 2, the balloon group 11 has a central region 121 that includes the midpoint P3 in the longitudinal direction x, a distal region 122 located distal to the central region 121, and a proximal region 123 located proximal to the central region 121. In other words, the portion of the balloon group 11 that includes the midpoint P3 in the longitudinal direction x is the central region 121.

[0024] The central region 121 is the region that includes the midpoint P3 in the longitudinal direction x of the balloon group 11. Preferably, the central region 121 is the region that includes the midpoint in the longitudinal direction x of the straight pipe section 111 of the balloon 10 included in the balloon group 11. Preferably, the central region 121 is a region with a length of 20% or more of the length of the straight pipe section 111 in the longitudinal direction x, more preferably a region with a length of 25% or more of the length of the straight pipe section 111, and even more preferably a region with a length of 30% or more of the length of the straight pipe section 111. By setting the lower limit of the length of the central region 121 in the longitudinal direction x to the above range, it becomes easier to determine the appropriate size of the central region 121.

[0025] The distal region 122 is a region located distal to the central region 121. In the longitudinal direction x, there may be further regions between the central region 121 and the distal region 122 that are different from the central region 121 and the distal region 122, but it is preferable that the central region 121 and the distal region 122 are adjacent. Furthermore, there may be further regions distal to the distal region 122 that are different from the distal region 122, but it is preferable that the distal region 122 is a region that includes the distal end 111d of the straight pipe section 111.

[0026] The distal region 122 is preferably a region having a length of 20% or more of the length of the straight pipe section 111 in the longitudinal direction x, more preferably a region having a length of 25% or more of the length of the straight pipe section 111, and even more preferably a region having a length of 30% or more of the length of the straight pipe section 111. By setting the lower limit of the length of the distal region 122 in the longitudinal direction x to the above range, it becomes easier to determine an appropriate size for the distal region 122.

[0027] The proximal region 123 is a region located proximal to the central region 121. In the longitudinal direction x, there may be further regions between the central region 121 and the proximal region 123 that are different from the central region 121 and the proximal region 123, but it is preferable that the central region 121 and the proximal region 123 are adjacent. Furthermore, there may be further regions proximal to the proximal region 123 that are different from the proximal region 123, but it is preferable that the proximal region 123 is a region that includes the proximal end 111p of the straight pipe section 111.

[0028] The proximal region 123 is preferably a region having a length of 20% or more of the length of the straight pipe section 111 in the longitudinal direction x, more preferably a region having a length of 25% or more of the length of the straight pipe section 111, and even more preferably a region having a length of 30% or more of the length of the straight pipe section 111. By setting the lower limit of the length of the proximal region 123 in the longitudinal direction x to the above range, it becomes easier to determine the appropriate size of the proximal region 123.

[0029] As shown in Figures 1 to 3 and Figure 5, the covering material 100 is a component positioned radially outward of the balloon group 11. The covering material 100 is located in the central region 121, and the tensile stress of the covering material 100 is higher than the tensile stress of the balloon membrane of the balloon 10. The balloon membrane is the membrane material that forms the balloon 10. The balloon catheter 1 may have one or more covering materials 100.

[0030] As shown in Figures 1 to 5, in the expanded state of the balloon group 11, the minimum outer diameter D121 of the balloon catheter 1 in the central region 121 is smaller than the maximum outer diameter D122 of the balloon catheter 1 in the distal region 122 and the maximum outer diameter D123 of the balloon catheter 1 in the proximal region 123. In other words, the maximum outer diameter D122 of the balloon catheter 1 in the distal region 122 is larger than the minimum outer diameter D121 of the balloon catheter 1 in the central region 121, and the maximum outer diameter D123 of the balloon catheter 1 in the proximal region 123 is larger than the minimum outer diameter D121 of the balloon catheter 1 in the central region 121. Note that the minimum outer diameter D121 of the balloon catheter 1 in the central region 121, the maximum outer diameter D122 of the balloon catheter 1 in the distal region 122, and the maximum outer diameter D123 of the balloon catheter 1 in the proximal region 123 refer to the outer diameter of the balloon group 11 when expanded. The term "when balloon group 11 is expanded" refers to the state in which all balloons 10 constituting balloon group 11 are expanded.

[0031] Because the tensile stress of the covering material 100 located in the central region 121 is higher than the tensile stress of the balloon membrane of the balloon 10, when the balloons 10 constituting the balloon group 11 expand, the expansion of the balloons 10 located in the central region 121 of the balloon group 11 is hindered by the covering material 100, which has a higher tensile stress than the balloon membrane forming the balloon 10. As a result, in the expanded state of the balloon group 11, the minimum outer diameter D121 of the balloon catheter 1 in the central region 121 is smaller than the maximum outer diameter D122 of the balloon catheter 1 in the distal region 122 and the maximum outer diameter D123 of the balloon catheter 1 in the proximal region 123.

[0032] Because the minimum outer diameter D121 of the balloon catheter 1 in the central region 121 is smaller than the maximum outer diameter D122 of the balloon catheter 1 in the distal region 122 and the maximum outer diameter D123 of the balloon catheter 1 in the proximal region 123, when the balloon group 11 is expanded, the outer diameter of the balloon catheter 1 in the central region 121 becomes smaller than the outer diameters of the balloon catheter 1 in the distal region 122 and the proximal region 123, forming a concave portion in the central region 121. Since a stenosis or bioprosthetic valve can be held in place by being sandwiched in this concave portion of the balloon group 11, the balloon catheter 1 can be made less prone to displacement of the balloon group 11 when expanded.

[0033] The maximum outer diameter D122 of the balloon catheter 1 in the distal region 122 may be larger than or smaller than the maximum outer diameter D123 of the balloon catheter 1 in the proximal region 123, but it is preferable that it be the same as the maximum outer diameter D123 of the balloon catheter 1 in the proximal region 123. The fact that the maximum outer diameter D122 of the balloon catheter 1 in the distal region 122 and the maximum outer diameter D123 of the balloon catheter 1 in the proximal region 123 are the same means that the maximum outer diameter D122 of the balloon catheter 1 in the distal region 122 and the maximum outer diameter D123 in the proximal region 123 are approximately the same, and specifically, it means that the maximum outer diameter D122 in the distal region 122 is 90% to 110% of the maximum outer diameter D123 in the proximal region 123. By having the same maximum outer diameter D122 in the distal region 122 and the same maximum outer diameter D123 in the proximal region 123 of the balloon catheter 1, the expansion force in the distal region 122 and the proximal region 123 during the expansion of the balloon group 11 can be made to be approximately the same, making it easier to uniformly expand stenoses, bioprosthetic valves, etc., held by the concave portion of the balloon group 11 from both sides.

[0034] The minimum outer diameter D121 of the balloon catheter 1 in the central region 121 is preferably 99% or less of the maximum outer diameter D122 of the balloon catheter 1 in the distal region 122 and the maximum outer diameter D123 of the balloon catheter 1 in the proximal region 123, more preferably 98% or less, and even more preferably 97% or less. By setting the upper limit of the ratio between the minimum outer diameter D121 of the balloon catheter 1 in the central region 121 and the maximum outer diameter D122 in the distal region 122 and the maximum outer diameter D123 in the proximal region 123 within the above range, a concave portion is more easily formed in the central region 121 of the balloon group 11, making it easier to hold stenoses, bioprosthetic valves, etc., in this concave portion. Furthermore, the minimum outer diameter D121 of the balloon catheter 1 in the central region 121 is preferably 80% or more of the maximum outer diameter D122 of the balloon catheter 1 in the distal region 122 and the maximum outer diameter D123 of the balloon catheter 1 in the proximal region 123, more preferably 85% or more, and even more preferably 90% or more. By setting the lower limit of the ratio between the minimum outer diameter D121 of the balloon catheter 1 in the central region 121 and the maximum outer diameter D122 in the distal region 122 and the maximum outer diameter D123 in the proximal region 123 within the above range, it becomes easier to increase the expansion force of the balloon 10 even in the concave portion of the balloon group 11, making it possible to efficiently expand stenotic areas and bioprosthetic valves.

[0035] The tensile stress of the covering material 100 is preferably 105% or more of the tensile stress of the balloon membrane of the balloon 10, more preferably 110% or more, and even more preferably 115% or more. By setting the lower limit of the ratio of the tensile stress of the covering material 100 to that of the balloon membrane within the above range, when the balloon group 11 is expanded, the covering material 100 is more likely to hinder the stretching of the balloon membrane, and the maximum outer diameter of the balloon catheter 1 in the central region 121 where the covering material 100 is placed is likely to be sufficiently smaller than the maximum outer diameter of the balloon catheter 1 in the distal region 122 and the proximal region 123. The upper limit of the ratio of the tensile stress of the covering material 100 to that of the balloon membrane is not particularly limited, but for example, it can be 500% or less, 450% or less, or 400% or less.

[0036] As shown in Figures 1 to 5, it is preferable that the covering material 100 is positioned at the midpoint P3. In other words, it is preferable that the covering material 100 is positioned to cover the portion of the central region 121 where the midpoint P3 is located in the longitudinal direction x of the straight tube portion 111. By positioning the covering material 100 at the midpoint P3, when the balloon group 11 is in an expanded state, the outer diameter of the central portion of the balloon group 11 can be made smaller than the outer diameter of other portions. As a result, a concave shape is formed in the central portion of the balloon group 11, making it easier to hold stenotic portions, bioprosthetic valves, etc., in the central portion of the balloon group 11.

[0037] It is preferable that the coefficient of friction of the covering material 100 is greater than the coefficient of friction of the balloon membrane. By having a coefficient of friction of the covering material 100 greater than the coefficient of friction of the balloon membrane forming the balloon 10, the coefficient of friction of the portion of the balloon group 11 where the covering material 100 is placed can be increased compared to the portion where the covering material 100 is not placed. In other words, the coefficient of friction of the central region 121 where the covering material 100 is placed can be increased compared to the coefficient of friction of the outer surface of other parts of the balloon catheter 1, reducing the slipperiness of the concave portion of the central region 121, making it less likely for the stenotic portion or bioprosthetic valve gripped by the concave portion to slip, thereby enhancing the effect of preventing displacement of the balloon group 11. The coefficient of friction of the covering material 100 and the outer surface of the balloon catheter 1 can be determined in accordance with JIS K7125 "Plastics - Test method for coefficient of friction of films and sheets".

[0038] As shown in Figures 1, 2, and 5, it is preferable that the covering material 100 is not placed in the distal region 122 and the proximal region 123. By not placing the covering material 100 in the distal region 122 and the proximal region 123, the covering material 100 is present in the central region 121, but not in the distal region 122 and the proximal region 123. As a result, the difference between the outer diameter of the balloon group 11 in the central region 121 and the outer diameter of the balloon group 11 in the distal region 122 and the proximal region 123 can be increased, making it easier to form a deep concave portion in the central part of the balloon group 11.

[0039] The covering material 100 is preferably a tubular body that shrinks at least in the radial direction y when heat is applied. Examples of tubular bodies that shrink at least in the radial direction y when heat is applied include heat-shrinkable tubing. Because the covering material 100 is a tubular body that shrinks at least in the radial direction y when heat is applied, it becomes easier to firmly fix the covering material 100 to the balloon group 11 by making close contact. Therefore, it becomes possible to prevent the covering material 100 from detaching from the balloon group 11 and scattering in the lumen of a living organism or the like.

[0040] The covering material 100 may also preferably contain fibers or wires. Specifically, examples of covering material 100 include a braided structure in which fibers or wires are woven, a structure in which fibers or wires are wrapped around at least one of the longitudinal direction x and the circumferential direction z, and a layered structure containing fibers or wires.

[0041] Examples of materials that make up the fibers or wires contained in the coating material 100 include metal wires such as stainless steel, carbon steel, and nickel-titanium alloy, as well as polyamide resins (e.g., nylon), polyolefin resins (e.g., polyethylene and polypropylene), polyester resins (e.g., PET), aromatic polyetherketone resins (e.g., PEEK), polyimide resins, aromatic polyamide resins (e.g., aramid), and fluororesins (e.g., PTFE, PFA, FEP, ETFE). The fibers or wires contained in the coating material 100 may have a monofilament structure or a multifilament structure.

[0042] Furthermore, it is preferable that the coating material 100 also contains a film-like substance. The film-like substance may be composed of a single material such as a synthetic resin, or it may be composed of multiple materials such as a base material and fillers.

[0043] Examples of materials constituting the film-like material or the base material of the film-like material include polyamide resins, polyester resins, polyurethane resins, polyolefin resins, polyimide resins, fluororesins, vinyl chloride resins, silicone resins, natural rubber, synthetic rubber, and the like. The materials constituting the filler may be organic materials, inorganic materials, or organic-inorganic composite materials. Examples of organic materials include thermosetting resins such as phenol, epoxy, and urea, and thermoplastic resins such as polyester, polyvinylidene chloride, polystyrene, and polymethacrylate. Examples of inorganic materials include shirasu, perlite, glass, silica, alumina, zirconia, and carbon. The shape of the filler may be, for example, spherical or other particulate, needle-shaped, fibrous, or plate-shaped.

[0044] As shown in Figures 1 to 5, it is preferable that the balloon group 11 includes an inner balloon 40 and a plurality of outer balloons 50 arranged radially outward from the inner balloon 40. In other words, it is preferable that the balloon group 11 has an inner balloon 40 and a plurality of outer balloons 50 arranged along the outer circumference of the inner balloon 40. By including an inner balloon 40 and a plurality of outer balloons 50 arranged radially outward from the inner balloon 40, the plurality of outer balloons 50 suppress the outward expansion of the inner balloon 40, and the inner balloon 40 suppresses the inward expansion of the plurality of outer balloons 50. As a result, the balloon group 11 is made highly pressure resistant by the inner balloon 40 and the plurality of outer balloons 50 suppressing each other's expansion, and the hardness of the plurality of balloons 10 constituting the balloon group 11 is increased, improving the expansion force. Furthermore, the mutual suppression of each other's expansion by the inner balloon 40 and the plurality of outer balloons 50 makes it more difficult for the plurality of balloons 10 constituting the balloon group 11 to inflate. Therefore, even when high pressure is applied to each of the balloons 10 that make up the balloon group 11, over-expansion of the balloons 10 is suppressed, preventing the balloon group 11 from expanding beyond the target outer diameter, thereby reducing damage to in vivo lumens such as the aortic valve and enhancing safety.

[0045] The number of inner balloons 40 may be multiple, but it is preferable that there be only one. In other words, it is preferable that the balloon group 11 has one inner balloon 40 and multiple outer balloons 50. By having only one inner balloon 40, when the balloon group 11 expands, the inner balloon 40 is less likely to move inside the multiple outer balloons 50. As a result, the inner balloon 40 can more easily suppress the expansion of the multiple outer balloons 50, and the hardness of the multiple balloons 10 constituting the balloon group 11 can be increased, making it easier to increase the expansion force.

[0046] The number of outer balloons 50 included in the balloon group 11 is preferably 3 or more, more preferably 4 or more, and even more preferably 5 or more. By setting the lower limit of the number of outer balloons 50 included in the balloon group 11 to the above range, it becomes easier to surround the outer circumference of the inner balloon 40 with multiple outer balloons 50, and the outer balloons 50 make it easier to suppress the expansion of the inner balloon 40. As a result, when fluid is introduced into the lumens of both the inner balloon 40 and the multiple outer balloons 50 to expand the balloon group 11, the inner balloon 40 becomes less likely to inflate, the hardness of the inner balloon 40 increases, and the expansion force of the balloon group 11 can be increased. Furthermore, the number of outer balloons 50 included in the balloon group 11 is preferably 20 or less, more preferably 12 or less, even more preferably 10 or less, and particularly preferably 8 or less. By setting the upper limit of the number of outer balloons 50 included in balloon group 11 to the above range, when balloon group 11 is expanded, the outer balloons 50 are less likely to move in the circumferential direction z, and the expansion of the inner balloon 40 can be more easily suppressed by multiple outer balloons 50.

[0047] The materials that make up the inner balloon 40 and the outer balloon 50 can be the same materials listed as the materials that make up the balloon 10. The materials that make up the outer balloon 50 may be the same as or different from the materials that make up the inner balloon 40.

[0048] The materials constituting each of the multiple outer balloons 50 included in the balloon group 11 may be different, but it is preferable that they be the same. In other words, it is preferable that the balloon group 11 includes multiple outer balloons 50 made of the same material. By having the same material constituting each of the multiple outer balloons 50, the degree of expansion and hardness of each of the multiple outer balloons 50 can be made to be of a similar degree in the circumferential direction z.

[0049] When the balloon group 11 is expanded, the maximum outer diameters of the multiple outer balloons 50 included in the balloon group 11 may be different, but it is preferable that they be the same. Having the same maximum outer diameters of the multiple outer balloons 50 included in the balloon group 11 means that the maximum outer diameters of the multiple outer balloons 50 are approximately the same, and specifically, it means that the maximum outer diameter of one outer balloon 50 is 90% to 110% of the maximum outer diameters of all the other outer balloons 50. When the balloon group 11 is expanded, having the same maximum outer diameters of the multiple outer balloons 50 included in the balloon group 11 makes it easier to synchronize the expansion timing of all the outer balloons 50 included in the balloon group 11, and makes it easier to control the expansion of the balloon group 11. Note that when the balloon group 11 is expanded, it means that all the balloons 10 constituting the balloon group 11 are expanded.

[0050] When the balloon group 11 expands, the maximum outer diameter of the inner balloon 40 may be the same as, or different from, the maximum outer diameter of each of the multiple outer balloons 50 included in the balloon group 11. When the maximum outer diameter of the inner balloon 40 is the same as the maximum outer diameter of each of the multiple outer balloons 50 included in the balloon group 11, it means that the maximum outer diameter of the inner balloon 40 is approximately the same as the maximum outer diameter of each of the multiple outer balloons 50 included in the balloon group 11. Specifically, it means that the maximum outer diameter of the inner balloon 40 is 90% to 110% of the average value of the maximum outer diameters of each of the multiple outer balloons 50 included in the balloon group 11. When the balloon group 11 expands, when the maximum outer diameter of the inner balloon 40 is the same as the maximum outer diameter of each of the multiple outer balloons 50 included in the balloon group 11, it becomes easier to balance the force that the inner balloon 40 tries to expand with the force that the multiple outer balloons 50 try to suppress the expansion of the inner balloon 40 by expanding. As a result, the hardness of the balloon group 11 increases, and it becomes easier to increase the expansion force of the balloon group 11.

[0051] When the balloon group 11 is expanded, it is preferable that the maximum outer diameter of the inner balloon 40 is larger than the maximum outer diameter of each of the multiple outer balloons 50 included in the balloon group 11. When the balloon group 11 is expanded, if the maximum outer diameter of the inner balloon 40 is larger than the maximum outer diameter of each of the multiple outer balloons 50 included in the balloon group 11, the multiple outer balloons 50 are more likely to be evenly arranged along the outer circumference of the expanded inner balloon 40. As a result, when the balloon group 11 is deflated, the multiple outer balloons 50 are more likely to fold, making it possible to reduce the outer diameter of the balloon catheter 1 in the part where the balloon group 11 is located.

[0052] When the balloon group 11 is expanded, the maximum outer diameter of the inner balloon 40 is preferably 1.10 times or more, more preferably 1.15 times or more, and even more preferably 1.20 times or more, the maximum outer diameter of each of the multiple outer balloons 50 included in the balloon group 11. By setting the lower limit of the ratio between the maximum outer diameter of the inner balloon 40 and the maximum outer diameter of each of the outer balloons 50 when the balloon group 11 is expanded to the above range, it becomes easier to evenly arrange the multiple outer balloons 50 along the outer circumference of the inner balloon 40. Furthermore, when the balloon group 11 is expanded, the maximum outer diameter of the inner balloon 40 is preferably 3.0 times or less, more preferably 2.5 times or less, and even more preferably 2.0 times or less, the maximum outer diameter of each of the multiple outer balloons 50 included in the balloon group 11. By setting the upper limit of the ratio between the maximum outer diameter of the inner balloon 40 and the maximum outer diameter of the outer balloon 50 during the expansion of the balloon group 11 to the above range, it becomes easier to reduce the outer diameter of the portion of the balloon catheter 1 where the balloon group 11 is located when the balloon 10 is deflated, thereby making the balloon catheter 1 less invasive.

[0053] When the balloon group 11 is expanded, the length L50 from the distal end 50d to the proximal end 50p of each of the multiple outer balloons 50 included in the balloon group 11 in the longitudinal direction x may be different, but it is preferable that they be the same. The fact that the length L50 from the distal end 50d to the proximal end 50p of each of the multiple outer balloons 50 included in the balloon group 11 in the longitudinal direction x is the same means that the length L50 in the longitudinal direction x of each of the multiple outer balloons 50 included in the balloon group 11 is approximately the same, and specifically, it means that the length L50 in the longitudinal direction x of one outer balloon 50 is 90% to 110% of the length L50 in the longitudinal direction x of all the other outer balloons 50. When the balloon group 11 expands, the length L50 in the longitudinal direction x of the multiple outer balloons 50 included in the balloon group 11 is the same, making it easier to synchronize the timing of the expansion of all the outer balloons 50 and making it easier to control the expansion of the balloon group 11.

[0054] When the balloon group 11 is expanded, it is preferable that the length L40 from the distal end 40d to the proximal end 40p of the inner balloon 40 in the longitudinal direction x is shorter than the length L50 from the distal end 50d to the proximal end 50p of the outer balloon 50 in the longitudinal direction x. When the length L40 of the inner balloon 40 is shorter than the length L50 of the outer balloon 50, the inner balloon 40 is constrained by the outer balloon 50 when the balloon group 11 is expanded, making it less likely for the inner balloon 40 to shift position. The balloon group 11 expands more easily in the area where the inner balloon 40 is present than in the area where the inner balloon 40 is absent, making it easier to apply pressure in the area where the inner balloon 40 is present, and enabling accurate pressure application to the target area. Furthermore, in the area where the inner balloon 40 is absent, the balloon group 11 does not expand as easily, making it difficult to apply pressure, thus reducing the load on areas other than the target area and enhancing the minimally invasive nature of the balloon catheter 1.

[0055] When the balloon group 11 is expanded, the length L40 from the distal end 40d of the inner balloon 40 to the proximal end 40p of the inner balloon 40 in the longitudinal direction x is preferably 95% or less, more preferably 90% or less, and even more preferably 85% or less, of the length L50 from the distal end 50d of the outer balloon 50 to the proximal end 50p of the outer balloon 50 in the longitudinal direction x. If the balloon group 11 has multiple inner balloons 40, the length L40 from the distal end 40d of the inner balloon 40 to the proximal end 40p of the inner balloon 40 refers to the length from the distal end 40d of the inner balloon 40 located furthest distal to the proximal end 40p of the inner balloon 40 located furthest proximal to the inner balloon 40. By setting the upper limit of the ratio of the length L40 of the inner balloon 40 to the length L50 of the outer balloon 50 within the above range, a balloon catheter 1 can be made that can accurately apply high pressure to the target site. Furthermore, when the balloon group 11 is expanded, the length L40 from the distal end 40d of the inner balloon 40 to the proximal end 40p of the inner balloon 40 in the longitudinal direction x is preferably 20% or more, more preferably 25% or more, and even more preferably 30% or more, of the length L50 from the distal end 50d of the outer balloon 50 to the proximal end 50p of the outer balloon 50 in the longitudinal direction x. By setting the lower limit of the ratio of the length L40 of the inner balloon 40 to the length L50 of the outer balloon 50 within the above range, it becomes easier to apply pressure to a sufficient area of ​​the target site with the balloon catheter 1, making it easier to expand the stenotic area or deform or destroy the bioprosthetic valve.

[0056] As shown in Figure 2, it is preferable that the distal end 40d of the inner balloon 40 is located proximal to the distal end 50d of the outer balloon 50, and the proximal end 40p of the inner balloon 40 is located distal to the proximal end 50p of the outer balloon 50. This configuration, where the distal end 40d of the inner balloon 40 is located proximal to the distal end 50d of the outer balloon 50, and the proximal end 40p of the inner balloon 40 is located distal to the proximal end 50p of the outer balloon 50, makes it less likely for the distal end of the inner balloon 40 and the distal end of the outer balloon 50 to overlap, and also less likely for the proximal end of the inner balloon 40 and the proximal end of the outer balloon 50 to overlap. As a result, when the balloon group 11 is deflated, it is possible to easily reduce the outer diameter of the portion of the balloon catheter 1 where the balloon group 11 is located.

[0057] Preferably, the distance from the distal end 40d of the inner balloon 40 to the distal end 50d of the outer balloon 50 in the longitudinal direction x is approximately the same as the distance from the proximal end 40p of the inner balloon 40 to the proximal end 50p of the outer balloon 50 in the longitudinal direction x. In other words, preferably, the distance from the distal end 40d of the inner balloon 40 to the distal end 50d of the outer balloon 50 in the longitudinal direction x is 90% to 110% of the distance from the proximal end 40p of the inner balloon 40 to the proximal end 50p of the outer balloon 50 in the longitudinal direction x. By having the distance from the distal end 40d of the inner balloon 40 to the distal end 50d of the outer balloon 50 be approximately the same as the distance from the proximal end 40p of the inner balloon 40 to the proximal end 50p of the outer balloon 50, the inner balloon 40 is more likely to be located in the central part of the balloon group 11 in the longitudinal direction x. As a result, the expansion of the balloon group 11 makes it easier to apply the load to the central part of the balloon group 11, and makes it easier to adjust the location where pressure is applied by the balloon group 11.

[0058] Preferably, the midpoint of the length L40 of the inner balloon 40, from its distal end 40d to its proximal end 40p in the longitudinal direction x, coincides with the midpoint of the length L50 of the outer balloon 50 constituting the balloon group 11, from its distal end 50d to its proximal end 50p in the longitudinal direction x. By having the midpoint of the length L40 of the inner balloon 40 coincide with the midpoint of the length L50 of the outer balloon 50 constituting the balloon group 11 in the longitudinal direction x, the balloon 10 can expand most easily at the midpoint of the length of the balloon group 11, making it easier to apply high pressure with the balloon group 11.

[0059] Although not shown in the diagram, the balloon group 11 includes a first outer balloon and a second outer balloon adjacent to the first outer balloon on one side of the inner balloon 40 in the circumferential z direction. When the balloon group 11 is expanded, it is preferable that the first outer balloon and the second outer balloon are in contact with each other. In other words, when the balloon group 11 is expanded, it is preferable that the outer surfaces of at least one pair of adjacent outer balloons 50 are in contact with each other. When the balloon group 11 is expanded, the contact between the first outer balloon and the second outer balloon causes the adjacent first outer balloon and second outer balloon to suppress each other's expansion when fluid is introduced into the balloons 10 constituting the balloon group 11 to expand the balloons 10. As a result, the pressure of the fluid introduced into the lumens of the first and second outer balloons increases, the hardness of both the first and second outer balloons increases, and the expansion force of the balloon group 11 can be increased.

[0060] In the expanded state of the balloon group 11, it is preferable that all the outer balloons 50 constituting the balloon group 11 are in contact with each other. Specifically, in the case of a balloon catheter 1 with the configuration shown in Figures 3 and 4, it is preferable that the outer balloons 50 are in contact with each other and with the outer balloons 50 located on either side of them in the circumferential direction z. In the expanded state of the balloon group 11, when all the outer balloons 50 constituting the balloon group 11 are in contact with each other, all the outer balloons 50 constituting the balloon group 11 suppress each other's expansion during expansion, and the internal pressure of all the outer balloons 50 increases. As a result, the overall hardness of the balloon group 11 increases, and the expansion force of the balloon group 11 can be further enhanced.

[0061] As shown in Figures 3 and 4, in the expanded state of the balloon group 11, it is preferable that the outer balloons 50 constituting the balloon group 11 are in contact with the outer circumferential surface of the inner balloon 40. In other words, in the expanded state of the balloon group 11, it is preferable that at least one of the outer balloons 50 constituting the balloon group 11 is in contact with the outer surface of the inner balloon 40. In the expanded state of the balloon group 11, the contact between the outer balloons 50 constituting the balloon group 11 and the outer balloon 50 makes it easier for the inner balloon 40 and the outer balloon 50 to suppress each other's expansion during the expansion of the balloon group 11. As a result, both the inner balloon 40 and the outer balloon 50 become less likely to inflate, making it easier to increase the expansion force of the balloon group 11. Furthermore, by the inner balloon 40 and the outer balloon 50 suppressing each other's expansion, it is also possible to prevent the inner balloon 40 and the outer balloon 50 from over-expanding when fluid is introduced into both the inner balloon 40 and the outer balloon 50 to create a high-pressure state.

[0062] In the expanded state of the balloon group 11, it is more preferable that all the outer balloons 50 constituting the balloon group 11 are in contact with the outer surface of the inner balloon 40. When all the outer balloons 50 constituting the balloon group 11 are in contact with the outer surface of the inner balloon 40 in the expanded state of the balloon group 11, the effect of the inner balloon 40 and the outer balloons 50 suppressing each other's expansion is enhanced, making it easier to further increase the expansion force of the balloon group 11.

[0063] As shown in Figures 1 to 5, it is preferable that the balloon catheter 1 further has a shaft 70 having a longitudinal direction x. The distal end of the shaft 70 is connected to the balloon 10, and it is preferable that the fluid that expands and deflates the balloon 10 is introduced and discharged through the lumen of the shaft 70.

[0064] The shaft 70 is preferably composed of resin, metal, or a combination of resin and metal. Using resin as a constituent material for the shaft 70 makes it easier to impart flexibility and elasticity to the shaft 70. Using metal as a constituent material for the shaft 70 can improve the delivery of the balloon catheter 1. Examples of resins that make up the shaft 70 include polyamide resins, polyester resins, polyurethane resins, polyolefin resins, fluororesins, vinyl chloride resins, silicone resins, natural rubber, and synthetic rubber. These may be used individually or in combination of two or more. Examples of metals that make up the shaft 70 include stainless steel such as SUS304 and SUS316, platinum, nickel, cobalt, chromium, titanium, tungsten, gold, Ni-Ti alloy, Co-Cr alloy, or combinations thereof. The shaft 70 may also have a laminated structure made of different materials or the same material.

[0065] Figure 1 shows a so-called rapid exchange type balloon catheter 1, which has a guidewire port 191 located midway from the distal to the proximal end of the shaft 70, and a guidewire tube 192 that functions as a guidewire insertion passage from the guidewire port 191 to the distal end of the shaft 70. When the balloon catheter 1 is of the rapid exchange type, it is preferable that the balloon catheter 1 has a distal shaft 75 and a proximal shaft 76, and the distal shaft 75 and the proximal shaft 76 are separate components, and the shaft 70 extending from the balloon 10 to the proximal end of the balloon catheter 1 may be formed by connecting the proximal end of the distal shaft 75 to the distal end of the proximal shaft 76. When the shaft 70 is composed of a distal shaft 75 and a proximal shaft 76 which are separate components, for example, the distal shaft 75 may be formed from resin and the proximal shaft 76 may be formed from metal. Alternatively, one shaft 70 may extend from the balloon 10 to the proximal end of the balloon catheter 1, and the distal shaft 75 and the proximal shaft 76 may be composed of multiple tubular members.

[0066] Alternatively, although not shown in the figures, the present invention can also be applied to so-called over-the-wire type balloon catheters, which have a guidewire insertion passage extending from the distal to the proximal end of the shaft. When the balloon catheter is of the over-the-wire type, it is preferable that the inflation lumen and guidewire lumen extend to a hub located on the proximal end, and that the proximal opening of each lumen is provided in a bifurcated hub.

[0067] It is preferable that the shaft 70 has a fluid channel and a guide wire insertion passage inside. To configure the shaft 70 to have a fluid channel and a guide wire insertion passage inside, for example, a guide wire tube 192 located inside the shaft 70 can function as a guide wire insertion passage, and the space between the shaft 70 and the guide wire tube 192 can function as a fluid channel. In such a configuration, it is preferable that the guide wire tube 192 extends from the distal end of the shaft 70 and penetrates the balloon 10, with the distal side of the balloon 10 connected to the guide wire tube 192 and the proximal side of the balloon 10 connected to the shaft 70.

[0068] As shown in Figure 5, it is preferable that the inner balloons 40 are arranged in multiple positions at different locations along the longitudinal direction x of the shaft 70. By arranging the inner balloons 40 in multiple positions at different locations along the longitudinal direction x of the shaft 70, when the balloon group 11 is expanded, the portions between the multiple inner balloons 40 do not expand, or expand less than other portions of the inner balloons 40. Therefore, the portions of the balloon group 11 located between the multiple inner balloons 40 do not allow the outer balloons 50 to expand significantly, making it easier to increase the depth of the concave portion formed in the center of the balloon group 11, and thus further enhancing the effect of preventing displacement of the balloon group 11.

[0069] In the balloon group 11, it is preferable that multiple inner balloons 40 are arranged in series with multiple outer balloons 50 arranged radially outward from the inner balloons 40 and in parallel with each other. In other words, it is preferable that the multiple inner balloons 40 are arranged in a row along the longitudinal direction x, and the multiple outer balloons 50 are arranged along the outer circumference of the inner balloons 40. Because the multiple inner balloons 40 are arranged in series with multiple outer balloons 50 arranged radially outward from the inner balloons 40 and in parallel with each other, the multiple outer balloons 50 suppress the outward expansion of the inner balloons 40, and the multiple outer balloons 50 suppress the inward expansion of the multiple outer balloons 50, so that the inner balloons 40 and the multiple outer balloons 50 suppress each other's expansion. As a result, the balloon group 11 can be made highly pressure resistant, the hardness of the multiple balloons 10 constituting the balloon group 11 can be increased, and the expansion force can be improved. Furthermore, because the inner balloons 40 and the multiple outer balloons 50 suppress each other's expansion, the multiple balloons 10 constituting the balloon group 11 become less likely to inflate. Therefore, even when high pressure is applied to each of the balloons 10 that make up the balloon group 11, over-expansion of the balloons 10 is suppressed, preventing the balloon group 11 from expanding beyond the target outer diameter, thereby reducing damage to in vivo lumens such as the aortic valve and enhancing safety.

[0070] The shaft 70 extends in the longitudinal direction x and has a guidewire lumen 93 through which a guidewire is inserted. It further has a guidewire tube 192 having a lumen that communicates with the guidewire lumen 93, and it is preferable that the guidewire tube 192 is positioned in the lumen of the inner balloon 40. The balloon catheter 1 having a guidewire tube 192 having a lumen that communicates with the guidewire lumen 93 makes it easy to insert the guidewire into the balloon catheter 1, and allows the balloon catheter 1 to be transported into the body along the guidewire. In addition, by inserting the guidewire into the guidewire tube 192, it is possible to prevent the guidewire from damaging the balloon 10, etc.

[0071] The materials constituting the guidewire tube 192 include, for example, polyolefin resins such as polyethylene and polypropylene, polyamide resins such as nylon, polyester resins such as PET, aromatic polyetherketone resins such as PEEK, polyether polyamide resins, polyurethane resins, polyimide resins, fluororesins such as PTFE, PFA, and ETFE, and synthetic resins such as polyvinyl chloride resins. Among these, it is preferable that the material constituting the guidewire tube 192 be a polyimide resin. By using a polyimide resin as the material constituting the guidewire tube 192, the lubricity of the guidewire tube 192 is improved. Therefore, it becomes easier to insert the guidewire into the lumen of the guidewire tube 192 and to advance the balloon catheter 1 into the body along the guidewire. Furthermore, the guidewire tube 192 may have a multilayer structure with a braided layer such as a metal braid. By having a multilayer structure for the guidewire tube 192, the strength of the guidewire tube 192, its lubricity relative to the guidewire, and its kink resistance can be improved.

[0072] As shown in Figure 1, it is preferable that the proximal end of the guidewire tube 192 is connected to the distal end of the shaft 70. If the shaft 70 has a distal shaft 75 and a proximal shaft 76, it is preferable that the proximal end of the guidewire tube 192 is connected to the distal end of the distal shaft 75. By connecting the proximal end of the guidewire tube 192 to the distal end of the shaft 70, the outer diameter of the balloon catheter 1 is less likely to increase, thereby improving minimally invasiveness.

[0073] The balloon 10 and the shaft 70 can be joined by adhesive bonding, welding, or by attaching a ring-shaped member to the overlapping portion of the balloon 10 and the shaft 70 and crimping it. In particular, it is preferable that the balloon 10 and the shaft 70 are joined by welding. By joining the balloon 10 and the shaft 70 by welding, the joint between the balloon 10 and the shaft 70 is less likely to come undone even when the balloon 10 is repeatedly expanded or contracted, and the joint strength can be improved.

[0074] Preferably, a tip member 193 is provided at the distal end of the balloon catheter 1. The tip member 193 may be provided at the distal end of the balloon catheter 1 by being connected to the distal end of the balloon 10 as a separate component from the guide wire tube 192, or the guide wire tube 192 extending distal to the distal end of the balloon 10 may function as the tip member 193.

[0075] As shown in Figures 1, 2, and 5, an X-ray opaque marker 194 may be placed on the guidewire tube 192 inside the balloon 10 at the location of the balloon 10 in the longitudinal axis x direction, so that the position of the balloon 10 can be confirmed by X-ray fluoroscopy.

[0076] The positions on the guidewire tube 192 where the radiopaque marker 194 is placed include, for example, the midpoint of the length L40 from the distal end 40d to the proximal end 40p of the inner balloon 40, the positions of the proximal and distal ends of the straight section of the inner balloon 40, and the positions of the proximal and distal ends of the straight section of the outer balloon 50. In particular, it is preferable that the positions on the guidewire tube 192 where the radiopaque marker 194 is placed are the positions of the proximal and distal ends of the straight section of the inner balloon 40. By placing the radiopaque marker 194 on the guidewire tube 192 located at the proximal and distal ends of the straight section of the inner balloon 40, it becomes easier to confirm the position where the balloon group 11 expands significantly due to the inner balloon 40. As a result, a balloon catheter 1 can be made that makes it easier to apply pressure to the target location.

[0077] As shown in Figure 1, a hub 5 may be provided on the proximal side of the shaft 70. The hub 5 may also be provided with a fluid injection section 6 that communicates with the fluid flow path supplied to the inside of the balloon 10.

[0078] The shaft 70 and the hub 5 can be joined by, for example, adhesive bonding or welding. In particular, it is preferable that the shaft 70 and the hub 5 are joined by adhesive bonding. By joining the shaft 70 and the hub 5 by adhesive bonding, the strength of the joint between the shaft 70 and the hub 5 can be increased, thereby improving the durability of the balloon catheter 1, especially when the materials constituting the shaft 70 and the hub 5 are different, for example, when the shaft 70 is made of a highly flexible material and the hub 5 is made of a highly rigid material.

[0079] If the balloon catheter 1 is a rapid exchange type, the outer wall of at least one of the distal shaft 75 and the proximal shaft 76 may be coated, or both the distal shaft 75 and the proximal shaft 76 may be coated. If the balloon catheter 1 is an over-the-wire type, the outer wall of the outer shaft may be coated.

[0080] The coating applied to the shaft 70 can be either a hydrophilic or hydrophobic coating, depending on the purpose. This coating can be applied by immersing the shaft 70 in a hydrophilic or hydrophobic coating agent, applying a hydrophilic or hydrophobic coating agent to the outer wall of the shaft 70, or covering the outer wall of the shaft 70 with a hydrophilic or hydrophobic coating agent. The coating agent may contain chemicals or additives.

[0081] Examples of hydrophilic coating agents include hydrophilic polymers such as polyvinyl alcohol, polyethylene glycol, polyacrylamide, polyvinylpyrrolidone, and methyl vinyl ether maleic anhydride copolymer, or hydrophilic coating agents made from any combination thereof.

[0082] Examples of hydrophobic coating agents include polytetrafluoroethylene (PTFE), ethylene fluoride propylene (FEP), perfluoroalkoxyalkanes (PFA), silicone oil, hydrophobic urethane resins, carbon coatings, diamond coatings, diamond-like carbon (DLC) coatings, ceramic coatings, and substances with low surface free energy terminated with alkyl groups or perfluoroalkyl groups.

[0083] The balloon catheter 1 of the present invention is preferably used to expand the aortic valve, deform a bioprosthetic valve implanted in the heart, or destroy a bioprosthetic valve. Specifically, the balloon catheter 1 of the present invention is preferably used to expand an aortic valve that has hardened due to calcification, etc., or to deform or destroy the prosthetic annulus of a bioprosthetic valve in order to replace a deteriorated bioprosthetic valve that has been implanted in the heart. Because the balloon catheter 1 of the present invention makes it easy to apply high pressure in the area where the inner balloon 40 is located, it is suitable for use in expanding hardened aortic valves and deforming or destroying bioprosthetic valves, which could not be sufficiently expanded with conventional balloon catheters. [Explanation of Symbols]

[0084] 1: Balloon catheter 5: Hub 6:Fluid injection part 10: Balloon 11: Balloon Group 40: Inner balloon 40d: Distal end of the medial balloon 40p: Proximal end of the inner balloon 50: Outer balloon 50d: Distal end of the outer balloon 50p: Proximal end of the outer balloon 70: Shaft 75: Distal shaft 76: Proximal shaft 93: Guide wire lumen 100: Covering material 111: Straight pipe section 111d: Distal end of the straight pipe section 111p: Proximal end of the straight pipe section 112: Distal tapered section 113: Proximal tapered section 114: Distal sleeve portion 115: Proximal sleeve portion 121: Central area 122: Distal region 123: Proximal region 191: Guide wire port 192: Guide wire tube 193: Tip component 194: X-ray opaque marker P3: Midpoint of the balloon group in the longitudinal direction D121: Minimum outer diameter of balloon catheter in the central region D122: Maximum outer diameter of balloon catheter in the distal region D123: Maximum outer diameter of balloon catheter in the proximal region L40: Length of the inner balloon L50: Length of the outer balloon

Claims

1. A group of balloons including multiple balloons arranged in parallel to each other in the circumferential direction, A balloon catheter having a covering material arranged radially outward of the balloon group, The balloon group has a central region including the midpoint in the longitudinal direction, a distal region located distal to the central region, and a proximal region located proximal to the central region. The covering material is arranged in the central region, The tensile stress of the coating material is higher than the tensile stress of the balloon membrane of the balloon. In the expanded state of the balloon group, the minimum outer diameter of the balloon catheter in the central region is smaller than the maximum outer diameter of the balloon catheter in the distal region and the maximum outer diameter of the balloon catheter in the proximal region.

2. The balloon catheter according to claim 1, wherein the covering material is positioned at the midpoint.

3. The balloon catheter according to claim 1 or 2, wherein the coefficient of friction of the covering material is greater than the coefficient of friction of the balloon membrane.

4. The balloon catheter according to claim 1 or 2, wherein the covering material is not provided in the distal region and the proximal region.

5. The balloon catheter according to claim 1 or 2, wherein the covering material is a tubular body having the property of shrinking at least radially when heat is applied.

6. The balloon catheter according to claim 1 or 2, wherein the covering material comprises fibers or wires.

7. The balloon catheter according to claim 1 or 2, wherein the covering material comprises a film-like material.

8. The balloon catheter according to claim 1 or 2, wherein the balloon group comprises an inner balloon and a plurality of outer balloons arranged radially outward from the inner balloon.

9. It further has a shaft that has a longitudinal direction, The balloon catheter according to claim 8, wherein the internal balloons are arranged in multiple locations at different positions in the longitudinal direction of the shaft.

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