Balloon catheter

Abstract

To provide a balloon catheter in which strength of a distal end portion of a balloon is high and a damage of the balloon is hard to occur when the balloon passes a hardened living body lumen.SOLUTION: A balloon catheter 1 includes: a balloon group 11 including a plurality of balloons 10 arranged in parallel to each other in a circumferential direction z; and a covering material 100 arranged radially outside the balloon group 11. The balloon group 11 includes a straight piping part 111, a distal side tapered part 112 located on the distal side from the straight piping part 111, and a proximal side tapered part 113 located on the proximal side from the straight piping part 111. The covering material 100 is arranged at least outside the distal side tapered part 112 and is not arranged outside the proximal side tapered part 113.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to 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] Aortic stenosis is a condition in which the aortic valve becomes hardened due to calcification, making it difficult to open and obstructing blood flow. Treatment for aortic stenosis involves open-chest surgery and catheter-based placement of a biological valve (artificial valve) to replace the hardened aortic valve.

[0004] An implanted bioprosthetic valve deteriorates over time due to calcification, wear, and other factors. When an implanted bioprosthetic valve deteriorates, it must be replaced. One procedure under consideration for replacing a bioprosthetic valve involves applying high pressure to the implanted bioprosthetic valve using a braided balloon catheter or multiple balloon catheters, deforming or destroying it, expanding the valve lumen, and then implanting a new bioprosthetic valve inside the deformed or destroyed bioprosthetic valve using techniques such as transcatheter aortic valve replacement.

[0005] As examples of balloon catheters used for dilating hardened stenotic lesions or placing biological valves, Patent Document 1 discloses a catheter characterized by having an expansion means composed of multiple expansion elements, the walls of which together form a substantially circular cross section when the expansion means is inflated. Patent Document 2 discloses a balloon catheter having multiple balloon members, with multiple outer balloon members arranged to surround the outer surface of an inner balloon member. Patent Document 3 discloses a balloon catheter having multiple balloons that expand independently without being affected by the other balloons and that remain separate from the other balloons after expansion. Patent Document 4 discloses a device having a perfusion balloon with an internal passage and a balloon disposed in the internal passage of the perfusion balloon. Patent Document 5 discloses a catheter including first, second, and 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] US Patent Application Publication No. 2012 / 0209375 [Patent Document 3] Japanese Patent Application Publication No. 2018-175550 [Patent Document 4] Special Publication No. 2018-536474 [Patent Document 5] International Publication No. 2021 / 054189 Summary of the Invention [Problem to be solved by the invention]

[0007] The conventional balloon catheters described above have multiple balloons, and therefore have a portion at the distal end of the balloon where the balloon tubes are bundled together. This portion where the balloon tubes are bundled together has gaps between the tubes, which can cause objects to get caught in the gaps and damage the balloon. Specifically, when passing through a hardened biological lumen, such as a calcified blood vessel or heart valve, the portion where the balloon tubes are bundled together at the distal end of the balloon can come into contact with or get caught on a calcified portion of the biological lumen, resulting in damage to the balloon. Another problem is that when the balloon passes through a hardened biological lumen, the distal end of the balloon, which is the leading portion of the balloon, can come into contact with the inner wall of the biological lumen, damaging the balloon membrane at the distal end and causing damage to the balloon.

[0008] In view of the above circumstances, an object of the present invention is to provide a balloon catheter whose distal end is less likely to become caught on other objects, whose distal end is highly strong, and whose balloon is less likely to break when passing through a hardened biological lumen. [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 balloon group including a plurality of balloons arranged parallel to each other in the circumferential direction; a covering material disposed radially outward of the balloon group, the balloon group has a straight pipe portion, a distal tapered portion located distal to the straight pipe portion, and a proximal tapered portion located proximal to the straight pipe portion, A balloon catheter, wherein the covering material is disposed on the outside of at least the distal tapered portion, but not on the outside of the proximal tapered portion. [2] The balloon catheter according to [1], wherein the covering material has a filter portion. [3] The covering material has an opening, The size of the opening is 31000 μm 2 More than 3150000μm 2 A balloon catheter according to the following [1] or [2]. [4] The covering material has an opening, The balloon catheter according to any one of [1] to [3], wherein the opening rate of the covering material is 20% or more and 50% or less. [5] A balloon catheter according to any one of [1] to [4], wherein the proximal end of the covering material is located proximal to the proximal end of the distal tapered portion and distal to the distal end of the proximal tapered portion. [6] The balloon catheter according to any one of [1] to [5], wherein the covering material is not disposed on the outside of the straight tube portion. [7] The balloon catheter according to any one of [1] to [6], wherein the covering material includes a fiber or a wire. [8] The balloon catheter according to any one of [1] to [7], wherein the covering material includes a film-like material. [9] The balloon catheter according to any one of [1] to [8], wherein the covering material includes a braided layer or a film layer and a wire material.

[10] The balloon group has a distal sleeve portion located distal to the distal tapered portion and a proximal sleeve portion located proximal to the proximal tapered portion, The balloon catheter according to any one of [1] to [9], wherein the thickness of the distal sleeve portion is greater than the thickness of the proximal sleeve portion.

[11] The balloon catheter according to any one of [1] to

[10] , wherein the balloon group includes an inner balloon and a plurality of outer balloons arranged radially outward of the inner balloon.

[12] The method further includes a shaft having a longitudinal direction; a distal end of the covering secured to the shaft; The balloon catheter according to any one of [1] to

[11] , wherein the proximal end of the covering material is fixed to the balloon group. [Effects of the Invention]

[0010] In the balloon catheter described above, the covering material is disposed at least on the outside of the distal tapered portion, but not on the outside of the proximal tapered portion. This protects the distal ends of the balloons with the covering material, making it possible to provide a balloon catheter in which the balloons are less likely to be damaged even if they come into contact with the wall of a biological lumen that has hardened due to calcification or the like. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is an overall view of a balloon catheter according to an embodiment of the present invention. [Figure 2] 2 is an enlarged view of a portion of the balloon catheter shown in FIG. 1 where a balloon is disposed. [Figure 3] 3 is a cross-sectional view of the balloon catheter shown in FIG. 1 taken along line III-III. [Figure 4] 4 shows a cross-sectional view of the balloon catheter shown in FIG. 1 taken along line IV-IV. [Figure 5] 2 shows a VV cross-sectional view of the balloon catheter shown in FIG. 1. [Figure 6] 10 is an enlarged view of a portion of a balloon catheter according to another embodiment of the present invention in which a balloon is disposed. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present invention will be described below based on the embodiments, but the present invention is not limited to the following embodiments, and can be implemented with appropriate modifications within the scope of the above and below-described purposes, and all such modifications are included within the technical scope of the present invention. In addition, hatching and component symbols may be omitted in each drawing for convenience. In such cases, reference should be made to the specification or other drawings. The dimensions of various components in the drawings may differ from actual dimensions, as priority is given to helping understand the features of the present invention.

[0013] A balloon catheter according to an embodiment of the present invention comprises a balloon group including a plurality of balloons arranged parallel to one another in the circumferential direction, and a covering material arranged radially outward of the balloon group, wherein the balloon group comprises a straight tube section, a distal tapered section located distal to the straight tube section, and a proximal tapered section located proximal to the straight tube section, and the covering material is arranged at least outside the distal tapered section, but not outside the proximal tapered section.

[0014] Hereinafter, a balloon catheter according to an embodiment of the present invention will be described with reference to Figures 1 to 6. Figure 1 is an overall view of a balloon catheter according to an embodiment of the present invention, and Figure 2 is an enlarged view of a portion of the balloon catheter shown in Figure 1 where a balloon is disposed. Figure 3 is a cross-sectional view taken along line III-III of the balloon catheter shown in Figure 1, showing a cross-sectional view perpendicular to the longitudinal direction at the portion where the balloon is present when the balloon is inflated. Figure 4 is a cross-sectional view taken along line IV-IV of the balloon catheter shown in Figure 1, showing a cross-sectional view perpendicular to the longitudinal direction at the portion where the balloon is present when the balloon is inflated. Figure 5 is a cross-sectional view taken along line V-V of the balloon catheter shown in Figure 1, showing a cross-sectional view perpendicular to the longitudinal direction at the portion where the balloon is present when the balloon is inflated. Figure 6 is an enlarged view of a portion where a balloon is disposed of a balloon catheter according to another embodiment of the present invention.

[0015] As shown in Figures 1 to 6, the balloon catheter 1 has 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 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 to 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 toward the user in the longitudinal direction x is referred to as the proximal side, and the direction opposite the proximal side, i.e., toward the patient, is referred to as the distal side. Furthermore, when each component or part of the balloon 10 is divided into two equal parts in the longitudinal direction x, the distal part of each component or part is referred to as the distal part of each component or part, and the proximal part of each component or part is referred to as the proximal part of each component or part. The distal end of each component or part is the most distal end of each component or part. The proximal end of each component or part is the most proximal end of each component or part. The term "end" includes the peripheral portion of the end. That is, the distal end refers to the distal end and the area surrounding the distal end, and the proximal end refers to the proximal end and the area surrounding the proximal end.

[0017] Components and parts other than the balloon 10 also have longitudinal, radial, and circumferential directions, which may or may not be the same as the longitudinal direction x, radial direction y, and circumferential direction z of the balloon 10. However, for ease of understanding, this specification will be described assuming that all components and parts have the same longitudinal, radial, and circumferential directions as the longitudinal direction x, radial direction y, and circumferential direction z of the balloon 10.

[0018] A balloon group 11 having a plurality of balloons 10 is located at the distal portion of the balloon catheter 1. The balloon 10 can be expanded by introducing a fluid into the lumen of the balloon 10, and can be deflated by discharging the fluid from the lumen of the balloon 10. To control the expansion and contraction of the balloon 10, a fluid can be introduced or discharged using an indeflator (a balloon pressurizer). The fluid may be, for example, saline or a mixture of a contrast agent and saline. The fluid may also be a pressurized fluid pressurized by a pump or the like.

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

[0020] As shown in Figures 2 and 6, the balloon group 11 has a straight tube section 111, a distal tapered section 112 located distal to the straight tube section 111, and a proximal tapered section 113 located proximal to the straight tube section 111.

[0021] The straight tube portion 111 is preferably substantially cylindrical with approximately the same diameter in the longitudinal direction x, but may have different diameters in the longitudinal direction x. The distal tapered portion 112 and the proximal tapered portion 113 preferably have a substantially conical or truncated conical shape with a diameter decreasing with increasing distance from the straight tube portion 111. Because the straight tube portion 111 has the largest diameter, when the balloon group 11 is expanded at a lesion such as a stenosis, the straight tube portions of the balloons 10 constituting the balloon group 11 can sufficiently contact the lesion, facilitating treatment such as dilation of the lesion. Furthermore, because the distal tapered portion 112 and the proximal tapered portion 113 have reduced diameters, the outer diameters of the proximal and distal ends of the balloons 10 constituting the balloon group 11 can be reduced when the balloon group 11 is deflated, thereby facilitating insertion of the balloon catheter 1 into a body cavity.

[0022] Preferably, 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, the straight tube portion 111, the distal tapered portion 112, and the proximal tapered portion 113 are portions that expand when a fluid is introduced into the balloon 10, whereas the distal sleeve portion 114 and the proximal sleeve portion 115 preferably do not expand. Since the distal sleeve portion 114 and the proximal sleeve portion 115 do not expand, at least a portion of the distal sleeve portion 114 and at least a portion of the proximal sleeve portion 115 can be easily fixed to another object, such as the shaft 70 of the balloon catheter 1. Details of the shaft 70 will be described later.

[0023] 1, 2, and 6, the covering material 100 is a member disposed radially outward from the balloon group 11. The covering material 100 is disposed at least outward from the distal tapered portion 112, but not outward from the proximal tapered portion 113. In other words, the covering material 100 may or may not be disposed outward from the straight tube portion 111.

[0024] Because the covering material 100 is disposed at least outside the distal tapered portion 112 and not outside the proximal tapered portion 113, the distal end of the balloon group 11 can be protected by the covering material 100. Therefore, when the balloon group 11 passes through a portion of a blood vessel or heart valve that has hardened due to calcification or the like, the balloon 11 is less likely to be damaged even if the distal end of the balloon group 11 comes into contact with the hardened luminal wall of the biological lumen.

[0025] The thickness of the covering material 100 is preferably 10 μm or more, more preferably 20 μm or more, and even more preferably 30 μm or more. By setting the lower limit of the thickness of the covering material 100 within the above range, the balloon 10 is less likely to be damaged even when it comes into contact with the wall of a biological lumen that has hardened due to calcification or the like. Furthermore, the thickness of the covering material 100 is preferably 100 μm or less, more preferably 70 μm or less, and even more preferably 50 μm or less. By setting the upper limit of the thickness of the covering material 100 within the above range, the covering material 100 can more easily follow the contraction of the balloon 10, reducing its bulkiness in the contracted state and ensuring its ability to pass through a biological lumen that has hardened due to calcification or the like.

[0026] The dressing material 100 preferably has a filter portion. A filter refers to a filter having liquid-permeable through-holes that allow liquid to flow from one side of the filter to the other through the through-holes and that has the function of capturing solids larger than the through-holes. The entire dressing material 100 may constitute the filter portion, or only a portion of the dressing material 100 may constitute the filter portion. In other words, it is preferable that at least a portion of the dressing material 100 is the filter portion. When the dressing material 100 has a filter portion, it can capture and collect hardened biological tissue due to calcification or the like that is scattered during inflation of the balloon 10 when the balloon catheter 1 is used in an antegrade approach, making it possible to prevent vascular obstruction due to the scattering of scattered material into the periphery.

[0027] The covering material 100 preferably has openings. The openings in the covering material 100 allow blood to pass through the covering material 100 in the body lumen. This allows blood to perfuse when the balloon group 11 is inflated, thereby improving the minimally invasive nature of the balloon catheter 1.

[0028] The shape of the openings as viewed in the thickness direction of the covering material 100 can be a polygonal shape such as a triangle, a rectangle, or a pentagon, a circle, an ellipse, or a combination of these. Note that polygons include polygons with clear corner vertices and straight sides, as well as rounded polygons with rounded corners and polygons with at least some of the sides curved.

[0029] The dressing 100 preferably has multiple openings. In other words, the dressing 100 preferably has multiple openings. When the dressing 100 has multiple openings, blood can easily pass through the dressing 100, facilitating smooth blood perfusion.

[0030] The opening size is 31000 μm 2 More than 3150000μm 2 In other words, the coating material 100 has a thickness of 31000 μm or less. 2 More than 3150000μm 2 It is preferable that the balloon catheter 1 has at least one opening of the following size: By setting the size of the opening within the above range, blood can be perfused while the distal end of the balloon group 11 is protected by the covering material 100, making it possible to provide a minimally invasive balloon catheter 1.

[0031] When the covering material 100 has a plurality of openings, the size of at least one opening is 31000 μm 2 More than 3150000μm 2 It is preferable that the average area per opening is 31000 μm or less for all openings. 2 More than 3150000μm 2 More preferably, it is:

[0032] The opening size is 31000 μm 2 It is preferable that the thickness is 70,000 μm or more. 2 More preferably, it is 150,000 μm or more. 2 More preferably, it is 400,000 μm or more. 2More preferably, it is 750,000 μm or more. 2 By setting the lower limit of the opening size within the above range, blood can easily pass through the opening in the body lumen, and the dressing 100 is less likely to obstruct the flow of blood. 2 Preferably, it is 2,550,000 μm or less. 2 More preferably, it is 2,300,000 μm or less. 2 More preferably, it is 1,800,000 μm or less. 2 Even more preferably, it is 1,150,000 μm or less. 2 By setting the upper limit of the opening size within the above range, the effect of the covering material 100 in protecting the balloon group 11 can be improved, making the balloons 10 less likely to be damaged.

[0033] The opening rate of the covering material 100 is preferably 20% or more and 50% or less. The opening rate of the covering material 100 refers to the ratio of the total area of ​​the openings in the covering material 100 to the total area of ​​the covering material 100. Setting the opening rate of the covering material 100 within the above range makes it easier to perfuse blood while protecting the distal ends of the balloon group 11 with the covering material 100, thereby improving the minimally invasive nature of the balloon catheter 1.

[0034] The opening rate of the dressing 100 is preferably 20% or more, more preferably 25% or more, and even more preferably 30% or more. By setting the lower limit of the opening rate of the dressing 100 within the above range, blood can easily pass through the dressing 100 through the openings, facilitating blood perfusion. Furthermore, the opening rate of the dressing 100 is preferably 50% or less, more preferably 45% or less, and even more preferably 40% or less. By setting the upper limit of the opening rate of the dressing 100 within the above range, the strength of the dressing 100 tends to be sufficient, and the dressing 100 is less likely to break when it comes into contact with a stenosis, a biological valve, or the like.

[0035] 2 and 6, the distal end 100d of the covering material 100 is preferably located distal to the distal end 112d of the distal tapered portion 112. By locating the distal end 100d of the covering material 100 distal to the distal end 112d of the distal tapered portion 112, the portion of the balloon group 11 distal to the distal end 112d of the distal tapered portion 112 that is likely to come into contact with a stricture, a biological valve, or the like when the balloon catheter 1 is inserted into a biological lumen can be protected by the covering material 100, thereby further improving the effect of preventing damage to the balloon 10.

[0036] 6, the proximal end 100p of the covering material 100 is preferably located proximal to the proximal end 112p of the distal tapered portion 112 and distal to the distal end 113d of the proximal tapered portion 113. By locating the proximal end 100p of the covering material 100 proximal to the proximal end 112p of the distal tapered portion 112 and distal to the distal end 113d of the proximal tapered portion 113, the covering material 100 is disposed not only outside the distal tapered portion 112 but also outside at least a portion of the straight tube portion 111. As a result, the area of ​​contact between the covering material 100 and the balloon group 11 is increased, making it easier to firmly fix the covering material 100 to the balloon group 11.

[0037] 2, it is also preferable that the covering material 100 is not disposed outside the straight tube portion 111. In other words, it is also preferable that the proximal end 100p of the covering material 100 is located distal to the proximal end 112p of the distal tapered portion 112. By not disposing the covering material 100 outside the straight tube portion 111, the covering material 100 is disposed outside the distal tapered portion 112, and is not disposed outside the straight tube portion 111 or the proximal tapered portion 113. Therefore, the balloon group 11 is protected by the covering material 100, and the balloon group 11 is less likely to interfere with blood flow, thereby improving the minimally invasive nature of the balloon catheter 1.

[0038] 2 and 6, the covering material 100 is preferably cylindrical with an internal cavity. By making the covering material 100 cylindrical, the distal end of the balloon group 11 can be covered over the entire area in the circumferential direction z, thereby enhancing the effect of protecting the distal end of the balloon group 11.

[0039] The covering material 100 preferably includes fibers or wires. Specifically, the covering material 100 may have, for example, a braided structure in which fibers or wires are woven, a structure in which fibers or wires are wound in at least one of the longitudinal direction x and the circumferential direction z, or a layer structure including fibers or wires.

[0040] Examples of materials constituting the fibers or wires contained in the covering material 100 include metal wires such as stainless steel, carbon steel, and nickel-titanium alloys, as well as polyamide resins (e.g., nylon), polyolefin resins (e.g., polyethylene and polypropylene), polyester resins (e.g., PET), aromatic polyether ketone resins (e.g., PEEK), polyimide resins, aromatic polyamide resins (e.g., aramid), and fluorine-based resins (e.g., PTFE, PFA, FEP, and ETFE). The fibers or wires contained in the covering material 100 may have a monofilament structure or a multifilament structure.

[0041] It is also preferable that the dressing 100 includes a film-like material. The film-like material may be made of a single material such as a synthetic resin, or may be made of multiple materials such as a base material and a filler.

[0042] 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, fluorine-containing resins, vinyl chloride resins, silicone resins, natural rubber, and synthetic rubber. 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, particulate (e.g., spherical), acicular, fibrous, or plate-like.

[0043] The covering material 100 also preferably includes a braided layer or a film layer and a wire material. That is, the covering material 100 is preferably configured by combining a braided layer or a film layer with a wire material. When the covering material 100 includes a braided layer or a film layer and a wire material, the wire material acts as a framework, increasing the rigidity of the braided layer or film material layer. This covers the distal ends of the balloons 11 with the covering material 100, making it easier to prevent damage to the balloons 11 even if the balloons 11 come into contact with the hardened inner wall of a biological lumen.

[0044] 4 and 5, the balloon group 11 has 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. The thickness T114 of the distal sleeve portion 114 is preferably greater than the thickness T115 of the proximal sleeve portion 115. That is, the thickness T114 of the balloon 10 at the distal sleeve portion 114 is preferably greater than the thickness T115 of the balloon 10 at the proximal sleeve portion 115. Because the thickness T114 of the distal sleeve portion 114 is greater than the thickness T115 of the proximal sleeve portion 115, the distal portion of the balloon group 11 is stronger than the proximal portion. This prevents damage to the balloon 10 and kinking of the balloon catheter 1 even when the distal portion of the balloon group 11 comes into contact with a lumen wall that has hardened due to calcification or the like.

[0045] The thickness T114 of the distal sleeve portion 114 and the thickness T115 of the proximal sleeve portion 115 are preferably greater than the thickness of the straight tube portion 111, the thickness of the distal tapered portion 112, and the thickness of the proximal tapered portion 113. In other words, the thickness T114 of the balloon 10 in the distal sleeve portion 114 and the thickness T115 of the balloon 10 in the proximal sleeve portion 115 are preferably greater than the thickness of the balloon 10 in the straight tube portion 111, the thickness of the balloon 10 in the distal tapered portion 112, and the thickness of the balloon 10 in the proximal tapered portion 113. Since the thicknesses T114, T115 of the distal sleeve portion 114 and the proximal sleeve portion 115 are greater than the thicknesses of the straight tube portion 111, the distal tapered portion 112, and the proximal tapered portion 113, the thickness T114 of the distal sleeve portion 114 and the thickness T115 of the proximal sleeve portion 115 are each thicker, making it easier to fix at least a portion of the distal sleeve portion 114 and at least a portion of the proximal sleeve portion 115 to other objects such as the shaft 70 of the balloon catheter 1.

[0046] As shown in FIG. 3 , the balloon group 11 preferably includes an inner balloon 40 and multiple outer balloons 50 arranged radially outward of the inner balloon 40. That is, the balloon group 11 preferably includes the inner balloon 40 and multiple outer balloons 50 arranged along the outer periphery of the inner balloon 40. By including the inner balloon 40 and multiple outer balloons 50 arranged radially outward of the inner balloon 40, the multiple outer balloons 50 suppress the outward expansion of the inner balloon 40, and the inner balloon 40 suppresses the inward expansion of the multiple outer balloons 50. As a result, the inner balloon 40 and the multiple outer balloons 50 mutually suppress their respective expansions, thereby increasing the pressure resistance of the balloon group 11 and increasing the hardness of the multiple balloons 10 constituting the balloon group 11, thereby improving their expansion force. Furthermore, the inner balloon 40 and the multiple outer balloons 50 mutually suppress their respective expansions, making the multiple balloons 10 constituting the balloon group 11 less likely to inflate. Therefore, even if 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 targeted outer diameter, reducing damage to the body's internal lumens such as the aortic valve and increasing safety.

[0047] The number of inner balloons 40 may be multiple, but is preferably one. That is, the balloon group 11 preferably has one inner balloon 40 and multiple outer balloons 50. Having only one inner balloon 40 makes it difficult for the inner balloon 40 to move inside the multiple outer balloons 50 when the balloon group 11 is inflated. As a result, the inner balloon 40 can more easily suppress the inflation of the multiple outer balloons 50, and the hardness of the multiple balloons 10 that make up the balloon group 11 can be increased, making it easier to increase the inflation force.

[0048] The number of outer balloons 50 included in the balloon group 11 is preferably three or more, more preferably four or more, and even more preferably five or more. By setting the lower limit of the number of outer balloons 50 included in the balloon group 11 within the above range, it becomes easier to surround the outer periphery of the inner balloon 40 with multiple outer balloons 50, and the outer balloons 50 are more likely to suppress the expansion of the inner balloon 40. As a result, when fluid is introduced into the lumen 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 expand, and the hardness of the inner balloon 40 increases, making it easier to increase the expansion force of the balloon group 11. 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 contained in the balloon group 11 to the above range, the outer balloons 50 are less likely to move in the circumferential direction z when the balloon group 11 is expanded, making it easier to suppress the expansion of the inner balloon 40 by the multiple outer balloons 50.

[0049] The materials constituting the inner balloon 40 and the outer balloon 50 can be the same as those listed as materials constituting the balloon 10. The material constituting the outer balloon 50 may be the same as the material constituting the inner balloon 40, or may be different.

[0050] The materials constituting each of the multiple outer balloons 50 included in the balloon group 11 may be different, but are preferably the same. In other words, the balloon group 11 preferably includes multiple outer balloons 50 made of the same material. By making each of the multiple outer balloons 50 out of the same material, the degree of expansion, hardness, etc. of each of the multiple outer balloons 50 in the circumferential direction z can be made to be approximately the same.

[0051] During inflation of the balloon group 11, the maximum outer diameters of the multiple outer balloons 50 included in the balloon group 11 may be different, but are preferably the same. The multiple outer balloons 50 included in the balloon group 11 having the same maximum outer diameter means that the maximum outer diameters of the multiple outer balloons 50 are approximately the same. Specifically, this 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. During inflation of the balloon group 11, the multiple outer balloons 50 included in the balloon group 11 have the same maximum outer diameter, which makes it easier to synchronize the inflation timing of all the outer balloons 50 included in the balloon group 11 and to control the inflation of the balloon group 11. Note that during inflation of the balloon group 11, this refers to a state in which all of the balloons 10 constituting the balloon group 11 are inflated.

[0052] During inflation of the balloon group 11, 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. The fact that 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 means that the maximum outer diameter of the inner balloon 40 and the maximum outer diameter of each of the multiple outer balloons 50 included in the balloon group 11 are approximately the same. Specifically, this means that the maximum outer diameter of the inner balloon 40 is between 90% and 110% of the average value of the maximum outer diameters of each of the multiple outer balloons 50. During inflation of the balloon group 11, having the maximum outer diameter of the inner balloon 40 be the same as the maximum outer diameter of each of the multiple outer balloons 50 included in the balloon group 11 facilitates balancing between the force exerted by the inner balloon 40 to expand and the force exerted by the multiple outer balloons 50 to suppress the expansion of the inner balloon 40. As a result, the rigidity of the balloon group 11 is increased, making it easier to increase the inflation force of the balloon group 11.

[0053] When the balloon group 11 is inflated, the maximum outer diameter of the inner balloon 40 is preferably larger than the maximum outer diameter of the multiple outer balloons 50 included in the balloon group 11. When the balloon group 11 is inflated, the maximum outer diameter of the inner balloon 40 is larger than the maximum outer diameter of the multiple outer balloons 50 included in the balloon group 11, which makes it easier to evenly arrange the multiple outer balloons 50 along the outer periphery of the inflated inner balloon 40. Therefore, 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 portion of the balloon catheter 1 where the balloon group 11 is located.

[0054] When the balloon group 11 is inflated, the maximum outer diameter of the inner balloon 40 is preferably at least 1.10 times, more preferably at least 1.15 times, and even more preferably at least 1.20 times the maximum outer diameter of the outer balloons 50 included in the balloon group 11. By setting the lower limit of the ratio of the maximum outer diameter of the inner balloon 40 to the maximum outer diameter of the outer balloon 50 when the balloon group 11 is inflated within the above range, the outer balloons 50 are more likely to be evenly arranged along the outer periphery of the inner balloon 40. Furthermore, when the balloon group 11 is inflated, the maximum outer diameter of the inner balloon 40 is preferably no more than 3.0 times, more preferably no more than 2.5 times, and even more preferably no more than 2.0 times the maximum outer diameter of the 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 when the balloon group 11 is expanded within 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 in a deflated state, making the balloon catheter 1 less invasive.

[0055] During inflation of the balloon group 11, 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 of each of the multiple outer balloons 50 included in the balloon group 11 may be different, but is preferably the same. 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 of each of the multiple outer balloons 50 included in the balloon group 11 being 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 means that the length L50 in the longitudinal direction x of one outer balloon 50 is between 90% and 110% of the lengths L50 in the longitudinal direction x of all the other outer balloons 50. Since the length L50 in the longitudinal direction x of the multiple outer balloons 50 included in the balloon group 11 is the same when the balloon group 11 is expanded, it becomes easier to align the timing at which all of the outer balloons 50 expand, making it easier to control the expansion of the balloon group 11.

[0056] During inflation of the balloon group 11, 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 shorter than 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. Because the length L40 of the inner balloon 40 is shorter than the length L50 of the outer balloon 50, the inner balloon 40 is restrained by the outer balloon 50 during inflation of the balloon group 11, making it less likely for the inner balloon 40 to shift position. This makes it easier for the balloon group 11 to inflate more significantly in the area where the inner balloon 40 is present than in the area where the inner balloon 40 is not present, making it easier to apply pressure to the area where the inner balloon 40 is present, allowing for accurate application of pressure to the target location. Furthermore, the balloon group 11 is less likely to inflate more significantly in the area where the inner balloon 40 is not present, making it harder to apply pressure, thereby reducing the likelihood of stress being applied to areas other than the target location, thereby improving the minimally invasive nature of the balloon catheter 1.

[0057] When the balloon group 11 is inflated, 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. 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, the balloon catheter 1 can be made to easily apply high pressure accurately to the target location. Furthermore, when the balloon group 11 is inflated, 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 at least 20%, more preferably at least 25%, and even more preferably at least 30% 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. 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 makes it easier to apply pressure to a sufficient area of ​​the target site using the balloon catheter 1, making it easier to dilate a stenotic site or deform or destroy a biological valve.

[0058] 2 and 4, 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 that the proximal end 40p of the inner balloon 40 is located distal to the proximal end 50p of the outer balloon 50. With a configuration in which 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, the distal end of the inner balloon 40 and the proximal end of the outer balloon 50 are less likely to overlap, and the proximal end of the inner balloon 40 and the proximal end of the outer balloon 50 are less likely to overlap. As a result, when the balloon group 11 is in a deflated state, the outer diameter of the portion of the balloon catheter 1 where the balloon group 11 is located can be easily reduced.

[0059] 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 preferably 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, 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 preferably 90% or more and 110% or less 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 making the distance from the distal end 40d of the inner balloon 40 to the distal end 50d of the outer balloon 50 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 positioned in the central portion of the balloon group 11 in the longitudinal direction x. As a result, the portion to which a load is applied by expanding the balloon group 11 is more likely to be the center of the balloon group 11, and the portion to which pressure is applied by the balloon group 11 can be more easily adjusted.

[0060] The position of the midpoint of the length L40 in the longitudinal direction x from the distal end 40d of the inner balloon 40 to the proximal end 40p of the inner balloon 40 preferably coincides with the position of the midpoint of the length L50 in the longitudinal direction x from the distal end 50d of the outer balloon 50 that constitutes the balloon group 11 to the proximal end 50p of the outer balloon 50. By having the position of the midpoint of the length L40 of the inner balloon 40 coincide with the position of the midpoint of the length L50 of the outer balloon 50 that constitutes the balloon group 11 in the longitudinal direction x, the balloon 10 is most likely to expand at the midpoint of the length of the balloon group 11, making it easier to apply high pressure by the balloon group 11.

[0061] As shown in FIG. 3 , the balloon group 11 includes a first outer balloon 51 and a second outer balloon 52 adjacent to the first outer balloon 51 on one side of the inner balloon 40 in the circumferential direction z. When the balloon group 11 is in an inflated state, the first outer balloon 51 and the second outer balloon 52 are preferably in contact with each other. That is, when the balloon group 11 is inflated, the outer surfaces of at least one pair of adjacent outer balloons 50 are preferably in contact with each other. When the balloon group 11 is inflated, the first outer balloon 51 and the second outer balloon 52 are in contact with each other. Therefore, when a fluid is introduced into the balloons 10 constituting the balloon group 11 to inflate the balloons 10, the adjacent first outer balloon 51 and the second outer balloon 52 mutually suppress the expansion of each other. As a result, the pressure of the fluid introduced into the lumen of the first outer balloon 51 and the second outer balloon 52 increases, increasing the hardness of both the first outer balloon 51 and the second outer balloon 52, thereby increasing the expansion force of the balloon group 11.

[0062] When the balloon group 11 is in an expanded state, all of the outer balloons 50 constituting the balloon group 11 are preferably in contact with adjacent outer balloons 50. Specifically, in the case of a balloon catheter 1 configured as shown in FIG. 3 , each outer balloon 50 is preferably in contact with the outer balloons 50 located on both sides of the outer balloon 50 in the circumferential direction z. When the balloon group 11 is in an expanded state, all of the outer balloons 50 constituting the balloon group 11 are in contact with adjacent outer balloons 50. As a result, when the balloon group 11 is expanded, all of the outer balloons 50 constituting the balloon group 11 suppress each other's expansion, and the internal pressure of all of the outer balloons 50 increases. This increases the hardness of the entire balloon group 11, further increasing the expansion force of the balloon group 11.

[0063] As shown in FIG. 3 , when the balloon group 11 is inflated, the outer balloon 50 of the balloon group 11 preferably contacts the outer peripheral surface of the inner balloon 40. That is, when the balloon group 11 is inflated, at least one of the outer balloons 50 of the balloon group 11 preferably contacts the outer surface of the inner balloon 40. When the balloon group 11 is inflated, the outer balloon 50 of the balloon group 11 contacts the outer peripheral surface of the inner balloon 40, which makes it easier for the inner balloon 40 and the outer balloon 50 to mutually suppress each other's expansion during inflation of the balloon group 11. As a result, both the inner balloon 40 and the outer balloon 50 are less likely to inflate, which makes it easier to increase the inflation force of the balloon group 11. Furthermore, because the inner balloon 40 and the outer balloon 50 mutually suppress their expansion, this also has the effect of preventing the inner balloon 40 and the outer balloon 50 from expanding excessively when a fluid is introduced into both the inner balloon 40 and the outer balloon 50 to create a high-pressure state.

[0064] It is more preferable that, when the balloon group 11 is in an expanded state, all of the outer balloons 50 constituting the balloon group 11 are in contact with the outer peripheral surface of the inner balloon 40. When the balloon group 11 is in an expanded state, all of the outer balloons 50 constituting the balloon group 11 are in contact with the outer peripheral surface of the inner balloon 40, which tends to enhance the effect of the inner balloon 40 and the outer balloon 50 in suppressing each other's expansion, making it easier to further increase the expansion force of the balloon group 11.

[0065] 1, 2, and 6, the balloon catheter 1 preferably further includes a shaft 70 having a longitudinal direction x. The distal portion of the shaft 70 is connected to the balloon 10, and a fluid for inflating and deflating the balloon 10 is preferably introduced and discharged through the lumen of the shaft 70.

[0066] The shaft 70 is preferably made of resin, metal, or a combination of resin and metal. Using resin as the material for the shaft 70 makes it easier to impart flexibility and elasticity to the shaft 70. Furthermore, using metal as the material for the shaft 70 can improve the deliverability of the balloon catheter 1. Examples of resins that can be used for the shaft 70 include polyamide resins, polyester resins, polyurethane resins, polyolefin resins, fluorine-containing resins, vinyl chloride resins, silicone resins, natural rubber, and synthetic rubber. These materials may be used alone or in combination. Examples of metals that can be used for the shaft 70 include stainless steels such as SUS304 and SUS316, platinum, nickel, cobalt, chromium, titanium, tungsten, gold, Ni-Ti alloys, Co-Cr alloys, and combinations thereof. The shaft 70 may also have a layered structure made of different or the same materials.

[0067] 1 shows a so-called rapid exchange type balloon catheter 1 having a guidewire port 191 midway from the distal side to the proximal side of the shaft 70 and a guidewire tube 192 that functions as a guidewire passage from the guidewire port 191 to the distal side of the shaft 70. When the balloon catheter 1 is a rapid exchange type, the balloon catheter 1 preferably has a distal shaft 75 and a proximal shaft 76. The distal shaft 75 and the proximal shaft 76 may be separate members, and the proximal end of the distal shaft 75 may be connected to the distal end of the proximal shaft 76 to form the shaft 70 that extends from the balloon 10 to the proximal end of the balloon catheter 1. When the shaft 70 is composed of the distal shaft 75 and the proximal shaft 76 that are separate members, the distal shaft 75 may be made of resin and the proximal shaft 76 may be made of metal, for example. 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 made up of multiple tubular members.

[0068] Alternatively, although not shown, the present invention can also be applied to a so-called over-the-wire balloon catheter, which has a guidewire passage extending from the distal side to the proximal side of the shaft. When the balloon catheter is an over-the-wire type, it is preferable that the inflation lumen and the guidewire lumen extend to a hub located on the proximal side, and that the proximal openings of each lumen are provided in a bifurcated hub.

[0069] It is preferable that the shaft 70 has a fluid flow path and a guidewire insertion path therein. For example, a configuration in which the shaft 70 has a fluid flow path and a guidewire insertion path therein can be achieved by configuring the guidewire tube 192 disposed inside the shaft 70 to function as the guidewire insertion path, and the space between the shaft 70 and the guidewire tube 192 to function as a fluid flow path. In such a configuration, it is preferable that the guidewire tube 192 extends from the distal end of the shaft 70 and passes through the balloon 10, with the distal side of the balloon 10 connected to the guidewire tube 192 and the proximal side of the balloon 10 connected to the shaft 70.

[0070] 6, it is preferable that the distal end of the covering material 100 is fixed to the shaft 70, and the proximal end of the covering material 100 is fixed to the balloon group 11. By fixing the distal end of the covering material 100 to the shaft 70 and the proximal end of the covering material 100 to the balloon group 11, the covering material 100 is fixed to both the balloon group 11 and the shaft 70. This allows the covering material 100 to be firmly fixed, which makes it easier to enhance the effect of the covering material 100 in protecting the distal end of the balloon group 11.

[0071] The covering material 100 and the balloon group 11, and the covering material 100 and the shaft 70 can be fixed together by, for example, bonding with an adhesive, welding, or fixing via another member such as attaching and crimping a ring-shaped member.

[0072] The shaft 70 has a guidewire lumen 93 extending in the longitudinal direction x and through which a guidewire is inserted, and further has a guidewire tube 192 having an inner cavity communicating with the guidewire lumen 93, and the guidewire tube 192 is preferably disposed in the inner cavity of the inner balloon 40. Since the balloon catheter 1 has the guidewire tube 192 having an inner cavity communicating with the guidewire lumen 93, it becomes easy to insert the guidewire into the balloon catheter 1, and the balloon catheter 1 can be delivered into the body along the guidewire. Furthermore, by inserting the guidewire into the guidewire tube 192, it is possible to prevent the guidewire from damaging the balloon 10, etc.

[0073] Examples of materials constituting the guidewire tube 192 include synthetic resins such as polyolefin resins (e.g., polyethylene, polypropylene, etc.), polyamide resins (e.g., nylon, etc.), polyester resins (e.g., PET, etc.), aromatic polyetherketone resins (e.g., PEEK, etc.), polyetherpolyamide resins, polyurethane resins, polyimide resins, fluorine-containing resins (e.g., PTFE, PFA, ETFE, etc.), and polyvinyl chloride resins. Among these, polyimide resins are preferred as the material constituting the guidewire tube 192. Using polyimide resin as the material constituting the guidewire tube 192 improves the lubricity of the guidewire tube 192. This facilitates inserting a guidewire through the lumen of the guidewire tube 192 and feeding the balloon catheter 1 into the body along the guidewire. The guidewire tube 192 may also have a multi-layer structure including a braided layer (e.g., a metal braid). The multi-layer structure of the guidewire tube 192 enhances the strength of the guidewire tube 192, its lubricity relative to the guidewire, and its kink resistance.

[0074] 1, the proximal end of the guidewire tube 192 is preferably connected to the distal end of the shaft 70. When the shaft 70 has a distal shaft 75 and a proximal shaft 76, the proximal end of the guidewire tube 192 is preferably connected to the distal end of the distal shaft 75. Connecting the proximal end of the guidewire tube 192 to the distal end of the shaft 70 prevents the outer diameter of the balloon catheter 1 from becoming large, thereby improving minimal invasiveness.

[0075] The balloon 10 and the shaft 70 can be joined by bonding with an adhesive, welding, or by attaching a ring-shaped member to the overlapping portion of the end of the balloon 10 and the shaft 70 and crimping them. Among these, 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 bond between the balloon 10 and the shaft 70 is less likely to come loose even when the balloon 10 is repeatedly expanded or contracted, and the bond strength can be improved.

[0076] A tip member 193 is preferably 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 as a separate member from the guidewire tube 192 by being connected to the distal end of the balloon 10, or the guidewire tube 192 extending distally of the distal end of the balloon 10 may function as the tip member 193.

[0077] As shown in Figures 1 and 2, a radiopaque marker 194 may be placed on the guidewire tube 192 inside the balloon 10 at the location where the balloon 10 is located in the longitudinal axis direction x so that the position of the balloon 10 can be confirmed under X-ray fluoroscopy.

[0078] Examples of positions on the guidewire tube 192 where the radiopaque marker 194 is located include the midpoint of the length L40 from the distal end 40d of the inner balloon 40 to the proximal end 40p of the inner balloon 40, the proximal and distal ends of the straight tube portion of the inner balloon 40, and the proximal and distal ends of the straight tube portion of the outer balloon 50. Among these, the positions on the guidewire tube 192 where the radiopaque marker 194 is located are preferably the proximal and distal ends of the straight tube portion of the inner balloon 40. By locating the radiopaque markers 194 on the guidewire tube 192 at the proximal and distal ends of the straight tube portion of the inner balloon 40, it becomes easier to confirm the positions where the balloon group 11 is greatly expanded by the inner balloon 40. As a result, the balloon catheter 1 can be configured to easily apply pressure to the target location.

[0079] 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 injecting section 6 that communicates with a flow path for fluid supplied to the inside of the balloon 10.

[0080] The shaft 70 and the hub 5 can be joined by, for example, bonding with an adhesive or welding. Among these, it is preferable that the shaft 70 and the hub 5 are joined by adhesive. By joining the shaft 70 and the hub 5 by adhesive, the bond strength between the shaft 70 and the hub 5 can be increased and the durability of the balloon catheter 1 can be improved when the shaft 70 and the hub 5 are made of different materials, for example, when the shaft 70 is made of a highly flexible material and the hub 5 is made of a highly rigid material.

[0081] When the balloon catheter 1 is a rapid exchange type, a coating may be applied to the outer wall of at least one of the distal shaft 75 and the proximal shaft 76, or may be applied to the outer walls of both the distal shaft 75 and the proximal shaft 76. When the balloon catheter 1 is an over-the-wire type, a coating may be applied to the outer wall of the outer shaft.

[0082] The coating applied to the shaft 70 can be a hydrophilic coating or a hydrophobic coating depending on the purpose, and 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 drugs or additives.

[0083] Examples of hydrophilic coating agents include hydrophilic polymers such as polyvinyl alcohol, polyethylene glycol, polyacrylamide, polyvinylpyrrolidone, methyl vinyl ether maleic anhydride copolymer, and the like, or hydrophilic coating agents made from any combination thereof.

[0084] Examples of hydrophobic coating agents include polytetrafluoroethylene (PTFE), fluorinated ethylene propylene (FEP), perfluoroalkoxyalkane (PFA), silicone oil, hydrophobic urethane resin, carbon coating, diamond coating, diamond-like carbon (DLC) coating, ceramic coating, and substances with low surface free energy terminated with alkyl groups or perfluoroalkyl groups.

[0085] The balloon catheter 1 of the present invention is preferably used for dilating an aortic valve, deforming a biological valve placed in the heart, or destroying a biological valve. Specifically, the balloon catheter 1 of the present invention is preferably used for dilating an aortic valve that has hardened due to calcification or the like, or for deforming or destroying an artificial valve annulus of a biological valve to replace a deteriorated biological valve placed in the heart. The balloon catheter 1 of the present invention is preferably used because it is easy to apply high pressure to the portion where the inner balloon 40 is located, and therefore is easily able to dilate a hardened aortic valve and deform or destroy a biological valve that cannot be sufficiently dilated with conventional balloon catheters. [Explanation of symbols]

[0086] 1: Balloon catheter 5: Hub 6:Fluid injection part 10: Balloon 11: Balloon group 40: Inner balloon 40d: Distal end of inner balloon 40p: Proximal end of inner balloon 50: Outer balloon 50d: Distal end of outer balloon 50p: Proximal end of outer balloon 51: First outer balloon 52: Second outer balloon 70: Shaft 75: Distal shaft 76: Proximal shaft 93: Guidewire lumen 100: Covering material 100d: Distal end of the covering 100p: Proximal end of the covering 111: Straight pipe section 112: Distal tapered section 112d: Distal end of distal tapered section 112p: Proximal end of distal tapered section 113: Proximal tapered section 113d: Distal end of proximal tapered section 114: Distal sleeve part 115: Proximal sleeve part 140: Tubular member 191: Guidewire port 192: Guidewire tube 193: Tip tip component 194: Radiopaque marker L40: Length of inner balloon L50: Length of outer balloon T114: Thickness of distal sleeve T115: Thickness of proximal sleeve

Claims

1. a balloon group including a plurality of balloons arranged in parallel with each other in the circumferential direction; a covering material disposed radially outward of the balloon group, the balloon group has a straight pipe portion, a distal tapered portion located distal to the straight pipe portion, and a proximal tapered portion located proximal to the straight pipe portion, A balloon catheter, wherein the covering material is disposed on the outside of at least the distal tapered portion, but not on the outside of the proximal tapered portion.

2. 2. The balloon catheter according to claim 1, wherein the covering material has a filter portion.

3. the covering has an opening; The size of the opening is 31000 μm ２ 3150000 μm or more ２ 2. The balloon catheter according to claim 1, wherein:

4. the covering has an opening; 2. The balloon catheter according to claim 1, wherein the opening ratio of the covering material is 20% or more and 50% or less.

5. 2. The balloon catheter according to claim 1, wherein the proximal end of the covering material is located proximal to the proximal end of the distal tapered portion and distal to the distal end of the proximal tapered portion.

6. 2. The balloon catheter according to claim 1, wherein the covering material is not disposed on the outside of the straight tube portion.

7. The balloon catheter according to claim 1 , wherein the covering material includes a fiber or a wire.

8. The balloon catheter according to claim 1 , wherein the covering material includes a film-like material.

9. 2. The balloon catheter according to claim 1, wherein the covering material includes a braided layer or a film layer and a wire material.

10. the balloon group has a distal sleeve portion located distal to the distal tapered portion and a proximal sleeve portion located proximal to the proximal tapered portion, The balloon catheter according to claim 1 , wherein the thickness of the distal sleeve portion is greater than the thickness of the proximal sleeve portion.

11. 2. The balloon catheter according to claim 1, wherein the balloon group includes an inner balloon and a plurality of outer balloons disposed radially outward of the inner balloon.

12. a shaft having a longitudinal direction; a distal end of the covering secured to the shaft; The balloon catheter of claim 1 , wherein the proximal end of the covering material is fixed to the balloon group.

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