Catheter balloon

Abstract

A balloon (3) has an expansion part (3B) that forms a cylindrical shape extending in an extension direction in an expanded state, a distal-end linking part (3A) provided to an end section of the expansion part (3B) on one side thereof, and a base-end linking part (3C) provided to an end section of the expansion part (3B) on the other side thereof. At least the expansion part (3B) has: a first portion (4A) that forms a vane part in a contracted state; and a second portion (5A) that, in the expanded state, is circumferentially adjacent to the first portion (4A) about a center axis (C1). In the process of deforming from the expanded state to the contracted state, the second portion (5A) moves towards the center axis (C1) ahead of the first portion (4A) and thereby forms, in the expansion part (3B), a recess indented towards the center axis (C1).

Description

[Technical field]

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

[0002] In order to improve the passage of the balloon catheter through blood vessels, the smaller the diameter of the balloon in the deflated state, the more preferable. The balloon catheter described in Patent Document 1 is held by a holder in a state in which the folded balloon membrane is wrapped around a support member to minimize the diameter. When in use, the balloon catheter is removed from the holder. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 62-114565 Summary of the Invention [Problem to be solved by the invention]

[0004] It is preferable that the diameter of the balloon is small even after it is expanded when used in a blood vessel and then deflated. However, in Patent Document 1, the balloon thin film is held by the holder in a state where it is wrapped around the support, and the diameter is reduced. Therefore, when the balloon thin film is removed from the holder, the diameter may not be reduced. For example, when the balloon thin film is removed from the holder and expanded when used, and then deflated after use and pulled out of the body, the diameter of the deflated balloon thin film may increase, making it difficult to pull out.

[0005] An object of the present invention is to provide a catheter balloon that can minimize its diameter even when deflated after expansion. [Means for solving the problem]

[0006] A catheter balloon according to a first aspect of the present invention is a catheter balloon that can be put into an inflated state and a contracted state in response to a change in internal pressure, and includes an expansion section that, in the process of changing from the contracted state to the inflated state, moves radially outwardly about a central axis extending in a predetermined extension direction and expands, and in the inflated state becomes a cylindrical shape extending in the extension direction; a tip connecting section that extends from a tip section that is an end on one side in the extension direction of the expansion section, and in the inflated state, the diameter of one end that is an end connected to the expansion section is larger than the diameter of the other end that is an end opposite to the one end; and a base end connecting portion which extends from a base end portion which is an end portion connected to the expansion portion in the expanded state and has a diameter greater than a diameter of the other end portion which is the end portion opposite to the one end portion, and at least the expansion portion has a plurality of first portions which form wing portions in the contracted state, and a plurality of second portions which are adjacent to the plurality of first portions in a circumferential direction centered on the central axis in the expanded state, and the plurality of second portions move toward the central axis ahead of the plurality of first portions during the process of deformation from the expanded state to the contracted state, thereby forming a depression which is recessed toward the central axis.

[0007] In the catheter balloon according to the first embodiment, when the catheter balloon is transformed from an expanded state to a contracted state, the second portions move toward the central axis before the first portions, and the first portions form wing portions. In this case, even if the catheter balloon is repeatedly transformed between an expanded state and a contracted state, the catheter balloon is always folded into a stable shape. Therefore, the diameter of the catheter balloon in the contracted state can be reduced.

[0008] A catheter balloon according to a second aspect of the present invention is a catheter balloon that can be put into an inflated state and a contracted state in response to a change in internal pressure, and includes an expansion section that, in the process of changing from the contracted state to the inflated state, moves radially outwardly about a central axis extending in a predetermined extension direction and expands, and in the inflated state becomes a cylindrical shape extending in the extension direction; a tip connecting section that is a portion extending from a tip section that is an end on one side in the extension direction of the expansion section, and in the inflated state, the diameter of one end that is an end connected to the expansion section is larger than the diameter of the other end that is an end opposite to the one end; The invention is characterized in that the expansion section has a base end connecting portion which extends from a certain base end portion and in the expanded state, the diameter of one end portion which is an end portion connected to the expansion section is larger than the diameter of the other end portion which is an end portion opposite to the one end portion, and at least the expansion section has a plurality of first portions which form a wing portion in the contracted state, and a plurality of second portions which are adjacent to the plurality of first portions in the circumferential direction centered on the central axis in the expanded state, and in that in the expanded state, the radial distance from the central axis to each of the plurality of second portions is shorter than the radial distance from the central axis to each of the plurality of first portions.

[0009] In the catheter balloon according to the second embodiment, when the catheter balloon is transformed from an expanded state to a contracted state, the second portions that are closer to the central axis in the expanded state move toward the central axis first, and the wing portions are formed by each of the first portions. In this case, even if the catheter balloon is repeatedly transformed between the expanded state and the contracted state, the catheter balloon is always folded into a stable shape. Therefore, the diameter of the catheter balloon in the contracted state can be reduced.

[0010] In the first and second aspects, the tip connector and the base connector may each have the plurality of first parts and the plurality of second parts, and each of the plurality of first parts and the plurality of second parts may extend from the other end of the tip connector to the other end of the base connector along the stretching direction. In this case, when the catheter balloon changes from the expanded state to the contracted state, the plurality of second parts of the tip connector and the base connector as well as the expansion part can be moved toward the central axis first. Therefore, the catheter balloon can be folded into a stable shape not only for the expansion part but also for the tip connector and the base connector. Therefore, the diameter of the catheter balloon in the contracted state can be reduced. In addition, when the catheter balloon in the contracted state is inserted into a blood vessel, the plurality of second parts serve as tension rods. In this case, the catheter balloon can be prevented from contracting in the stretching direction, and the tip connector and the base connector can be prevented from expanding in the radial direction. Furthermore, since the possibility that the diameter of the distal end connecting portion and the proximal end connecting portion will increase when folded can be reduced, the catheter balloon can be made to pass easily through blood vessels.

[0011] In a first aspect, the tip connecting part and the base connecting part each have the plurality of first parts and the plurality of second parts, each of the plurality of first parts and the plurality of second parts extending from the other end of the tip connecting part to the other end of the base connecting part along the stretching direction, and the amount of the depression formed in the process of transforming from the expanded state to the contracted state may be larger in the expansion part than in the tip connecting part and the base connecting part. In this case, when the catheter balloon is contracted, the folding time of the expansion part having a large diameter can be shortened and the folded shape can be stabilized.

[0012] In the first and second aspects, each of the second portions may include a rigid portion having a higher rigidity than the first portions. When the catheter balloon changes from an inflated state to a deflated state, a force that moves the second portions toward the central axis first acts on the rigid portion. Therefore, the catheter balloon can achieve a configuration in which the second portions move toward the central axis first by the rigid portion.

[0013] In the first and second aspects, the radial thickness of each of the second parts may be greater than the radial thickness of each of the first parts. In this case, the speed at which the second parts move toward the central axis when the catheter balloon changes from an inflated state to a deflated state is slow immediately after the start of the movement, and then becomes faster. In this case, the second parts can stably fold the catheter balloon.

[0014] In the first and second aspects, in the inflated state, the distance between the inner surfaces of the second parts and the central axis may be shorter than the distance between the inner surfaces of the first parts and the central axis. That is, the inner surfaces of the second parts are disposed closer to the central axis than the inner surfaces of the first parts. In this case, when the catheter balloon changes from an inflated state to a deflated state, the second parts tend to move toward the central axis before the first parts. Therefore, even if the catheter balloon changes repeatedly between an inflated state and a deflated state, the catheter balloon can always be folded into a stable shape.

[0015] In the first and second aspects, in the inflated state, the distance between the outer surfaces of the second portions and the central axis may be longer than the distance between the outer surfaces of the first portions and the central axis. In this case, when the catheter balloon changes from an inflated state to a deflated state, the second portions tend to move toward the central axis before the first portions. Therefore, even if the catheter balloon changes repeatedly between an inflated state and a deflated state, the catheter balloon can always be folded into a stable shape.

[0016] In the first and second embodiments, the outer surfaces of the second portions may be rounded. In this case, the second portions can be prevented from getting caught on the inner wall of the blood vessel when the catheter balloon passes through the blood vessel, thereby improving the passage of the catheter balloon through the blood vessel.

[0017] In the first and second aspects, the second portions may be disposed at equal intervals in the circumferential direction. In this case, when the catheter balloon changes from an inflated state to a deflated state, the wing portions formed by the first portions can have a uniform size. Therefore, the catheter balloon can be deflated uniformly in the circumferential direction.

[0018] In the first and second aspects, the shape may be memorized in a state in which the plurality of second portions are recessed toward the central axis, which makes it easy to realize a configuration in which the plurality of second portions move toward the central axis first when the catheter balloon changes from an inflated state to a deflated state.

[0019] In the first and second aspects, the first portions and the second portions may be made of the same material, which makes it easier to manufacture the catheter balloon.

[0020] In the first and second aspects, one or more slits may be provided in the portion of the second parts that is located at the tip connecting part. In this case, when the folded catheter balloon is inserted into a blood vessel, the tip connecting part does not unfold and the flexibility of the tip connecting part is ensured. This improves the passability of the catheter balloon.

[0021] In the first and second aspects, one or more slits may be provided in the portion of the second parts that is located at the base end connector. In this case, when the folded catheter balloon is pulled out of the blood vessel, the base end connector does not unfold and the flexibility of the base end connector is ensured. This can further improve the passability of the catheter balloon.

[0022] In the first and second aspects, one or more slits may be provided in the portion of the second portions that is disposed in the inflatable portion. In this case, the inflatable portion does not expand when the folded catheter balloon is moved in a blood vessel. This can further improve the passability of the catheter balloon.

[0023] In the first and second aspects, each of the first portions has a vertex at which a curvature becomes maximum during the process of deformation from the expanded state to the contracted state, a first extension portion extending from a connection portion with the second portion adjacent to one side in the circumferential direction to the vertex, and a second extension portion extending from a connection portion with the second portion adjacent to the other side in the circumferential direction to the vertex, and the length of the second extension portion may be longer than the length of the first extension portion. In this case, when the catheter balloon is deformed from the expanded state to the contracted state, the second portion can be easily covered by the first portion.

[0024] In the first and second aspects, each of the first portions may have a vertex whose curvature is maximized during the process of deformation from the expanded state to the contracted state, and during the process of deformation from the expanded state to the contracted state, the distance between the vertex and the second portion adjacent to one side of the first portion having the vertex in the circumferential direction may be shorter than the distance between the vertex and the second portion adjacent to the other side of the first portion having the vertex in the circumferential direction. In this case, the catheter balloon can easily cover the second portion with the first portion when the catheter balloon is deformed from the expanded state to the contracted state.

[0025] In the first and second aspects, each of the first parts has a vertex at which the curvature is maximum during the process of deformation from the expanded state to the contracted state, a first extension part extending from a connection part with the second part adjacent to one side of the circumferential direction to the vertex, and a second extension part extending from a connection part with the second part adjacent to the other side of the circumferential direction to the vertex, and during the process of deformation from the expanded state to the contracted state, at least a part of the first extension part of the first part having the vertex may be located on the other side of the circumferential direction with respect to a virtual plane extending in the radial direction through the central axis and the vertex. In this case, each of the first parts is more likely to cover the second part adjacent to one side of the circumferential direction. Therefore, when the catheter balloon is deformed from the expanded state to the contracted state, it is more likely that the first part can cover the second part. [Brief description of the drawings]

[0026] [Figure 1] FIG. 2 is a diagram showing a balloon catheter 1A with a balloon 3 in an inflated state. [Diagram 2] 1 is a diagram showing a balloon 3 deforming from a contracted state to an inflated state. [Diagram 3] 1A and 1B are diagrams showing a balloon 3 deforming from an inflated state to a deflated state. [Figure 4] FIG. 2 is a diagram showing a balloon 3 in a balloon catheter 1B. [Diagram 5] FIG. 2 is a diagram showing the balloon 3 in the balloon catheter 1C. [Figure 6] FIG. 2 is a diagram showing a balloon 3 in a balloon catheter 1D. [Figure 7] FIG. 1 shows a balloon catheter 1E. [Figure 8] 1A is a diagram showing the balloon 3 of the balloon catheter 1F deforming from an expanded state to a contracted state. FIG. [Figure 9] FIG. 2 is a diagram showing the balloon 3 of the balloon catheter 1F in a deflated state. [Figure 10] 1A is a diagram showing the balloon 3 of the balloon catheter 1G deforming from an expanded state to a contracted state. FIG. [Figure 11] FIG. 2 is a diagram showing the balloon 3 of the balloon catheter 1G in a deflated state. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] The embodiments (1A to 1E) of the balloon catheter 1 according to the present invention will be described with reference to the drawings. The drawings to be referred to are used to explain the technical features that can be adopted by the present invention. The configurations of the device described are merely illustrative examples and are not intended to be limiting. The balloon catheter 1 can dilate stenotic lesions formed in blood vessels. Furthermore, the balloon catheter 1 can crush or incise the lesion by applying the second part 5A described later to the lesion.

[0028] <Balloon catheter 1A> A balloon catheter 1A will be described with reference to Fig. 1. The balloon catheter 1A has a catheter shaft 2 and a balloon 3.

[0029] <Catheter shaft 2> The balloon 3 is connected to one end of a tubular catheter shaft 2. The balloon catheter 1A is used with a hub (not shown) connected to the other end of the catheter shaft 2. The hub is capable of supplying compressed fluid to the balloon 3 via the catheter shaft 2.

[0030] One of the two ends of the catheter shaft 2 is referred to as the "tip side." The other of the two ends of the catheter shaft 2 is referred to as the "base side." The direction extending along the catheter shaft 2 is referred to as the "extension direction." The axis extending in the extension direction through the center of the catheter shaft 2 is referred to as the central axis C1. In a cross section taken along a plane perpendicular to the central axis C1 (hereinafter simply referred to as a "cross section"), in the radial direction centered on the central axis C1, the side closer to the central axis C1 is referred to as the "inner side," and the side away from the central axis C1 is referred to as the "outer side."

[0031] The catheter shaft 2 has an outer tube 21 and an inner tube 22. The outer tube 21 and the inner tube 22 are each flexible. The inner diameter of the outer tube 21 is larger than the outer diameter of the inner tube 22. The inner tube 22 is disposed in the lumen of the outer tube 21, except for a predetermined portion on the tip side. The predetermined portion on the tip side of the inner tube 22 protrudes toward the tip side from the tip end (hereinafter referred to as the "tip 211") of the outer tube 21. The tip end (hereinafter referred to as the "tip 221") of the inner tube 22 is disposed on the tip side of the tip 211 of the outer tube 21. The predetermined portion on the tip side of the inner tube 22 is referred to as the "protruding portion 225". The material of the outer tube 21 and the inner tube 22 is not particularly limited. As an example of the material of the outer tube 21 and the inner tube 22, a polyamide resin is used.

[0032] A compressed fluid supplied from the hub flows through the space in the lumen of the outer tube 21 other than the lumen of the inner tube 22. A guide wire (not shown) is inserted through the lumen of the inner tube 22.

[0033] <Balloon 3> The balloon 3 can be deformed between a contracted state and an expanded state by changing the internal pressure depending on the presence or absence of a supply of compressed fluid by a hub (not shown). FIG. 1 shows the balloon 3 in an expanded state. The distal end of the balloon 3 (hereinafter referred to as "distal end 3D") is connected to the vicinity of the distal end 221 of the protruding portion 225 of the inner tube 22 by thermal welding. The proximal end of the balloon 3 (hereinafter referred to as "proximal end 3P") is connected to the vicinity of the distal end 211 of the outer tube 21 by thermal welding. The balloon 3 covers the protruding portion 225 of the inner tube 22 from the outside. The material of the balloon 3 is not particularly limited. As an example of the material of the balloon 3, a polyamide resin is used.

[0034] In the balloon 3, a tip connecting portion 3A, an expansion portion 3B, and a base end connecting portion 3C are defined. The tip connecting portion 3A is a region that extends while expanding in diameter from the tip end 3D to the base end 3P in the balloon 3 in an expanded state. The base end connecting portion 3C is a region that extends while expanding in diameter from the base end 3P to the tip end 3D in the balloon 3 in an expanded state. The expansion portion 3B is a region sandwiched between the tip connecting portion 3A and the base end connecting portion 3C in the balloon 3 in an expanded state, and has a substantially constant diameter along the extension direction. In the expanded state, the expansion portion 3B is cylindrical and extends in the extension direction. The balloon 3 has an inner surface 301 and an outer surface 302.

[0035] The tip end of the expansion section 3B is referred to as the "tip end 30D" and the base end end is referred to as the "base end 30P". The tip connecting section 3A extends from the end connected to the tip end 30D of the expansion section 3B toward the tip end 3D. The diameter of the cross section of the tip connecting section 3A is largest at the end connected to the tip end 30D of the expansion section 3B and smallest at the tip end 3D. The base end connecting section 3C extends from the end connected to the tip end 30D of the expansion section 3B toward the base end 3P. The diameter of the cross section of the base end connecting section 3C is largest at the end connected to the base end 30P of the expansion section 3B and smallest at the base end 3P.

[0036] The distal end connecting portion 3A, the inflatable portion 3B, and the proximal end connecting portion 3C of the balloon 3 each have a first portion 41A, 42A, 43A (hereinafter collectively referred to as the "first portion 4A") and a second portion 51A, 52A, 53A (hereinafter collectively referred to as the "second portion 5A"). The first portion 4A and the second portion 5A each extend in the extension direction between the distal end 3D of the distal end connecting portion 3A and the proximal end 3P of the proximal end connecting portion 3C. The first portion 4A and the second portion 5A are formed of the same material.

[0037] The direction perpendicular to the central axis C1 among the directions extending along the inflatable portion 3B of the balloon 3 is referred to as the "circumferential direction E1". The first portion 4A and the second portion 5A are arranged in the circumferential direction E1 in the order of the second portion 51A, the first portion 41A, the second portion 52A, the first portion 42A, the second portion 53A, and the first portion 43A. The first portion 4A and the second portion 5A are adjacent to each other in the circumferential direction E1 and alternately arranged. The second portions 51A, 52A, and 53A are arranged at equal intervals in the circumferential direction E1. The portion of the inner surface 301 of the balloon 3 corresponding to the first portion 4A is referred to as the inner surface 401, and the portion corresponding to the second portion 5A is referred to as the inner surface 501. The portion of the outer surface 302 of the balloon 3 corresponding to the first portion 4A is referred to as the outer surface 402, and the portion corresponding to the second portion 5A is referred to as the outer surface 502.

[0038] The first portion 4A and the second portion 5A have different rigidities. The second portion 5A has a higher rigidity than the first portion 4A. The difference in rigidity between the first portion 4A and the second portion 5A may be caused by at least one of the results of various well-known rigidity tests. As described above, the first portion 4A and the second portion 5A are made of the same material, but the difference in rigidity occurs by making the thicknesses of the first portion 4A and the second portion 5A different.

[0039] When the balloon 3 is in an inflated state, the inner surface 401 and the outer surface 402 of the first portion 4A are curved along a circular arc centered on the central axis C1. The radial distance between the central axis C1 and the inner surface 401 of the first portion 4A is denoted as D11. The radial distance between the central axis C1 and the outer surface 402 of the first portion 4A is denoted as D12. The radial thickness of the first portion 4A corresponds to the radial distance between the inner surface 401 and the outer surface 402 of the first portion 4A and is denoted as T11. In detail, the curvatures of both ends of the inner surface 401 and the outer surface 402 in the circumferential direction E1 are slightly larger than the curvatures of the portions other than both ends (see FIG. 2(C) and FIG. 3(A)).

[0040] The outer surface 502 of the second portion 5A has a vertex 500 that protrudes most radially outward. The outer surface 502 has outer surfaces 502A, 502B that correspond to two side surfaces of a triangle in cross section. The ends of the outer surfaces 502A, 502B opposite the vertex 500 are connected to the ends of the first portion 4A adjacent to the circumferential direction E1. The plane connecting the ends of the outer surfaces 502A, 502B opposite the vertex 500 is called the "bottom surface 503". The direction that extends perpendicular to the bottom surface 503 and from the bottom surface 503 through the vertex 500 is called the "protruding direction Y1". In the expanded state, the protruding direction Y1 faces radially outward. The inner surface 501 of the second portion 5A is located radially inward relative to the bottom surface 503. The distance between the central axis C1 and the inner surface 501 of the second portion 5A is denoted as D21. The distance between the central axis C1 and the vertex 500 is denoted as D22. The radial thickness of the second portion 5A corresponds to the radial distance between the inner surface 501 of the second portion 5A and the vertex 500 and is denoted as T21.

[0041] The radial thickness T21 of the second portion 5A in the expanding portion 3B is constant in the stretching direction. The radial thickness T21 of the second portion 5A in the distal connecting portion 3A is largest at a portion connecting with the distal end 30D of the expanding portion 3B, and decreases toward the distal end 3D. The radial thickness T21 of the second portion 5A in the proximal connecting portion 3C is largest at a portion connecting with the proximal end 30P of the expanding portion 3B, and decreases toward the proximal end 3P.

[0042] In any cross section in the stretching direction, the thickness T21 of the second portion 5A is greater than the thickness T11 of the first portion 4A. In the expanded state, the distance D21 between the inner surface 501 of the second portion 5A and the central axis C1 is shorter than the distance D11 between the inner surface 401 of the first portion 4A and the central axis C1. That is, the radial distance from the central axis C1 to the second portion 5A is shorter than the radial distance from the central axis C1 to the first portion 4A. In the expanded state, the distance D22 between the outer surface 502 of the second portion 5A and the central axis C1 is longer than the distance D12 between the outer surface 402 of the first portion 4A and the central axis C1.

[0043] As shown in FIG. 2(C), in the cross section of the balloon 3 in the inflated state, a virtual circle S is defined that contacts the first portions 41A-43A from the outside. In this case, both ends of each of the first portions 41A-43A in the circumferential direction E1 and each of the second portions 51A-53A that are closer to the central axis C1 than the bottom surface 503 (see FIG. 1) are located inside the virtual circle S. Therefore, in the balloon 3, depressions 51B, 52B, 53B (hereinafter collectively referred to as "depressions 5B") are formed by depressing the second portions 51A, 52A, 53A toward the central axis C1. Note that the shape of the balloon 3 is memorized so that the shape is stabilized in a state in which the depressions 51B, 52B, 53B are formed in the second portions 51A, 52A, 53A.

[0044] The method for memorizing the shape of the first portion 4A is not particularly limited. For example, the balloon 3 may be produced by blow molding using a mold having the same shape as the shape of the balloon 3 in the state where the depression 5B is formed in the second portion 5A. In this case, it is possible to produce a balloon 3 whose shape is memorized in the state where the depression 5B is formed in the second portion 5A.

[0045] As shown in FIG. 2(A), the balloon 3 in a deflated state has wing portions 41B, 42B, and 43B (hereinafter collectively referred to as "wing portion 4B"). Wing portions 41B, 42B, and 43B are formed by folding first portions 41A, 42A, and 43A of the balloon 3 and wrapping them around second portions 52A, 53A, and 51A from the outside, respectively. Second portion 5A is covered from the outside by wing portion 4B. Wing portion 4B is also called a "flap" or "wing."

[0046] <Deflate / inflate balloon 3> FIG. 2 shows the process in which the balloon 3 changes from a contracted state to an expanded state. Suppose that compressed fluid is supplied from a hub (not shown) to the balloon 3 in a contracted state shown in FIG. 2(A). In this case, as shown in FIG. 2(B), the first portions 41A-43A of the balloon 3 expand, and the wing portions 41B-43B (see FIG. 2(A)) are eliminated. Furthermore, when compressed fluid is supplied to the balloon 3, the second portions 51A-53A move radially outward, respectively, and move away from the central axis C1. As a result, as shown in FIG. 2(C), the balloon 3 becomes expanded. Note that in FIG. 2(C), in order to facilitate understanding of the depressions 51B, 52B, and 53B, the depression amounts of the depressions 51B, 52B, and 53B are shown larger than the actual depression amounts (the depression amounts of the depressions 51B, 52B, and 53B shown in FIG. 1). The same applies to FIG. 3(A) described later.

[0047] FIG. 3 shows the process in which the balloon 3 changes from an expanded state to a contracted state. Assume that the compressed fluid is removed from the balloon 3 in the expanded state shown in FIG. 3(A). Here, as described above, the shape of the balloon 3 is stored in a state in which the depressions 51B-53B are formed in the second portions 51A-53A. Therefore, as shown in FIG. 3(B), in response to the removal of the compressed fluid, the entire balloon 3 moves a predetermined amount toward the central axis C1, and then the second portions 51A-53A move toward the central axis C1 before the first portions 41A-43A. Therefore, the amount of depression of the depressions 51B-53B with respect to the imaginary circle S becomes larger than that in the expanded state.

[0048] In addition, since the radial thickness T21 of the second portion 5A is larger than the radial thickness T11 of the first portion 4A in the cross section, the speed at which the second portions 51A-53A move toward the central axis C1 is slow immediately after starting to move and then becomes faster. The depressions 51B-53B are larger in the inflatable portion 3B than in the distal connecting portion 3A and the proximal connecting portion 3C. Therefore, the maximum diameter of the balloon 3, i.e., the diameter of the inflatable portion 3B, rapidly decreases.

[0049] As the movement amount of the second portions 51A-53A in the direction toward the central axis C1 increases, as shown in Fig. 3(C), the first portions 41A-43A except for both end portions in the circumferential direction E1 are pushed outward and protrude outward beyond the imaginary circle S. As shown in Fig. 3(D), when the second portions 51A-53A have moved to a position close to the inner tube 22, the first portions 41A-43A are folded.

[0050] 3(E), the first portions 41A to 43A in the folded state cover the second portions 51A to 53A from the outside, forming wing portions 41B to 43B, whereby the balloon 3 is in a deflated state.

[0051] <Action and effect> When the balloon 3 changes from an expanded state to a contracted state, the second portion 5A, which has a shorter radial distance from the central axis C1 in the expanded state, moves toward the central axis C1 before the first portion 4A. In the process of the second portion 5A moving, the first portion 4A forms the wing portion 4B, and the balloon 3 finally changes to a contracted state. In this case, the balloon catheter 1A can stabilize the shape of the balloon 3 in the contracted state, so that the diameter of the balloon 3 in the contracted state can be reduced to maintain good passage through the blood vessel. In addition, even if the balloon 3 is repeatedly deformed between the expanded state and the contracted state, the balloon 3 is always folded into a stable shape. Therefore, the balloon catheter 1A can reduce the diameter of the balloon 3 in the contracted state.

[0052] When the balloon 3 is manufactured by blow molding, the second portion 5A can suppress localized pressure from being applied to the area corresponding to the inflatable portion 3B, thereby preventing the balloon 3 from bursting during the manufacturing process.

[0053] The first portion 4A and the second portion 5A of the balloon 3 are provided at the tip connecting portion 3A, the expansion portion 3B, and the base end connecting portion 3C. In this case, when the balloon catheter 1A is transformed from the expanded state to the contracted state, the second portion 5A can be moved forward toward the central axis C1 at each of the tip connecting portion 3A, the expansion portion 3B, and the base end connecting portion 3C of the balloon 3. In this case, the balloon 3 can be folded into a stable shape at each of the tip connecting portion 3A, the expansion portion 3B, and the base end connecting portion 3C. Therefore, the diameter of the balloon 3 in the contracted state can be made small over the entire area in the stretching direction. In addition, the possibility that the diameter of the tip connecting portion 3A and the base end connecting portion 3C will increase when folded can be reduced, so that the balloon 3 can be easily passed through the blood vessel.

[0054] The amount of depression of depressions 51B-53B formed in the process of the balloon 3 changing from an expanded state to a contracted state is larger in the expansion section 3B than in the distal end connecting section 3A and the proximal end connecting section 3C. Therefore, the time required for the expansion section 3B, which has a larger diameter, to fold during contraction of the balloon 3 can be shortened. Also, because the wing sections 41B-43B are smoothly formed, the folded shape of the balloon 3 can be stabilized.

[0055] The second portion 5A has a higher rigidity than the first portion 4A. In this case, when the balloon 3 changes from an expanded state to a contracted state, a force tends to act on the second portion 5A to move toward the central axis C1 before the first portion 4A. Therefore, the balloon 3 can be configured so that the second portion 5A moves toward the central axis C1 first by adjusting the magnitude relationship of the rigidity between the second portion 5A and the first portion 4A.

[0056] In addition, the behavior of the balloon 3 in the deflated state that tends to spread outward in the radial direction can be suppressed by the second portion 5A having higher rigidity. Therefore, even if the balloon 3 is repeatedly deformed between the inflated state and the deflated state, the first portion 4A can stably form the wing portions 4B. Therefore, the diameter of the balloon 3 in the deflated state can be stably maintained small, and the wing portions 4B can be suppressed from becoming flat and folded.

[0057] In the balloon 3, the second portion 5A has a higher rigidity than the first portion 4A, and the second portion 5A is provided over the entire area of ​​the balloon 3 from the distal end 3D to the proximal end 3P. In this case, when the balloon 3 in a contracted state is inserted into a blood vessel, the second portion 5A functions as a tension rod. Therefore, the balloon catheter 1A can prevent the distal end connecting portion 3A and the proximal end connecting portion 3C from expanding in the radial direction due to the contraction of the balloon 3 in the extension direction.

[0058] The thickness T21 of the second portion 5A is greater than the thickness T11 of the first portion 4A. In this case, the speed at which the second portion 5A moves toward the central axis C1 when the balloon 3 changes from an expanded state to a contracted state is slow immediately after the start of the movement, and then becomes faster. This allows the balloon catheter 1A to stably fold the balloon 3 by the second portion 5A.

[0059] In the expanded state, the distance D21 between the inner surface 501 of the second portion 5A and the central axis C1 is shorter than the distance D11 between the inner surface 401 of the first portion 4A excluding both ends in the circumferential direction E1 and the central axis C1. That is, the inner surface 501 of the second portion 5A is disposed closer to the central axis C1 than the inner surface 401 of the first portion 4A. In addition, in the expanded state, the distance D22 between the outer surface 502 of the second portion 5A and the central axis C1 is longer than the distance D12 between the outer surface 402 of the first portion 4A and the central axis C1. In these cases, when the balloon 3 is transformed from the expanded state to the contracted state, the second portion 5A is more likely to move toward the central axis C1 before the first portion 4A. Therefore, even if the balloon 3 is repeatedly transformed between the expanded state and the contracted state, the balloon 3 can always be folded into a stable shape.

[0060] In the inflated state, the distance D22 is longer than the distance D12, so that the outer surface 502 of the second portion 5A protrudes outward from the outer surface 402 of the first portion 4A. In this case, when the balloon 3 is inflated in a blood vessel, the second portion 5A is likely to come into contact with the inner wall of the blood vessel. Therefore, the balloon catheter 1A allows the second portion 5A of the balloon 3 to act favorably on the blood vessel.

[0061] The second portions 51A-53A are disposed at equal intervals in the circumferential direction E1. In this case, when the balloon 3 changes from an expanded state to a contracted state, the wing portions 41B-43B formed by the first portions 41A-43A can have uniform sizes. Therefore, the balloon catheter 1A can contract the balloon 3 uniformly in the circumferential direction E1.

[0062] The shape of the balloon 3 is stored in a state in which the second portions 51A-53A have recesses 51B-53B recessed toward the central axis C1. In this case, it is easy to realize a configuration in which the second portion 5A moves first toward the central axis C1 when the balloon 3 changes from an expanded state to a contracted state.

[0063] The first portion 4A and the second portion 5A of the balloon 3 are made of the same material, which makes it possible to easily manufacture the balloon catheter 1A.

[0064] <Modification> The present invention is not limited to the above embodiment, and various modifications are possible. The number of the first portion 4A and the second portion 5A of the balloon 3 is not limited to three each as in the above embodiment, and may be any other number. The first portion 4A and the second portion 5A of the balloon 3 may be formed of different members. For example, the balloon 3 may be provided with the second portion 5A on the outer surface of a cylindrical portion that becomes cylindrical in an inflated state. In this case, the portion between two adjacent second portions 5A of the cylindrical portion corresponds to the first portion 4A.

[0065] In the above, when the balloon 3 changes from an expanded state to a contracted state, the second portion 5A moves toward the central axis C1 before the first portion 4A. In contrast, for example, immediately after the balloon 3 starts to change from an expanded state to a contracted state, the second portion 5A may start moving first, and then the first portion 4A may start moving toward the central axis C1. Alternatively, the first portion 4A may start moving first, and then the second portion 5A may start moving toward the central axis C1.

[0066] The first portion 4A and the second portion 5A may be provided only in the inflation portion 3B of the balloon 3, and may not be provided in the tip connecting portion 3A and the base end connecting portion 3C. In this case, the second portion 5A may not extend from the tip end 30D to the base end 30P of the inflation portion 3B, and may be divided in the extension direction. Alternatively, the first portion 4A and the second portion 5A may be provided in the inflation portion 3B of the balloon 3, or one of the tip connecting portion 3A and the base end connecting portion 3C.

[0067] The second portion 5A may be made of different materials at a portion inside the distance D12 in the radial direction and a portion outside the distance D12 in the radial direction. In this case, the portion inside the distance D12 in the radial direction may be made of the same material as the first portion 4A, and the portion outside the distance D12 in the radial direction may be made of a material different from that of the first portion 4A. The portion of the second portion 5A outside the distance D12 in the radial direction may have higher rigidity than the portion inside the distance D12 in the radial direction. In other words, the portion of the second portion 5A outside the distance D12 in the radial direction may form a rigid portion.

[0068] The thickness T11 of the first portion 4A and the thickness T21 of the second portion 5A may be the same. In this case, the outer surface 502 of the second portion 5A does not need to protrude outward from the outer surface 402 of the first portion 4A.

[0069] The second portions 51A to 53A do not have to be arranged at equal intervals in the circumferential direction E1. For example, the second portions 51A to 53A may be provided locally in a part of the balloon 3 in the circumferential direction E1.

[0070] The inflated balloon 3 may not have a depression 5B. In this case, the inner surface of the balloon 3 in the inflated state may be formed into a cylindrical shape without any irregularities. The first portion 4A and the second portion 5A of the balloon 3 may be formed from different materials. For example, the second portion 5A may be formed by doping a new material into the material forming the first portion 4A.

[0071] <Balloon catheter 1B> As in the balloon 3 of the balloon catheter 1B shown in Fig. 4, the outer surface 502 of each of the second portions 51A-53A may be rounded. In this case, when the balloon 3 passes through a blood vessel, the second portion 5A can be prevented from getting caught on the inner wall of the blood vessel. Therefore, the balloon catheter 1B can improve the passability of the balloon 3 through the blood vessel.

[0072] It goes without saying that the shape of the outer surface 502 of the second portion 5A is not limited to the above, and may take various shapes depending on the application and function.

[0073] <Balloon catheter 1C> 5, in an inflated state, the distance D11 between the inner surface 401 of the first portion 4A and the central axis C1 may be the same as the distance D21 between the inner surface 501 of the second portion 5A and the central axis C1. In this case, no step is formed on the inner surface 301 of the balloon 3, and the inner surfaces 401, 501 form a perfect circle in cross section.

[0074] <Balloon catheter 1D> 6, in an inflated state, the distance D12 between the outer surface 402 of the first portion 4A and the central axis C1 may be the same as the distance D22 between the outer surface 502 of the second portion 5A and the central axis C1. In this case, no step is formed on the outer surface 302 of the balloon 3, and the outer surfaces 402, 502 form a perfect circle in cross section. Also, a step is formed on the inner surface 301 of the balloon 3 that protrudes inward at a portion corresponding to the inner surface 501 of the second portion 5A.

[0075] <Balloon Catheter 1E> 7, a slit 7A may be provided in the second portion 5A arranged in the tip connecting portion 3A, a slit 7B may be provided in the second portion 5A arranged in the expansion portion 3B, and two slits 7C may be provided in the second portion 5A arranged in the base connecting portion 3C. The slits 7A to 7C are cuts or notches extending from the outer surface 502 of the second portion 5A toward the central axis C1.

[0076] The slit 7A provided in the second portion 5A disposed in the tip connecting portion 3A can maintain the flexibility of the tip connecting portion 3A while suppressing the expansion of the tip connecting portion 3A in the contracted state. Therefore, the balloon catheter 1E can improve the passability when the balloon 3 in the contracted state is inserted into a blood vessel.

[0077] The slit 7C provided in the second portion 5A disposed at the base end connecting portion 3C can maintain the flexibility of the base end connecting portion 3C while suppressing the expansion of the base end connecting portion 3C in the contracted state. Therefore, the balloon catheter 1E can improve the passability when the balloon 3 in the contracted state is pulled out of the blood vessel.

[0078] The two slits 7B provided in the second portion 5A disposed in the expansion portion 3B can suppress the expansion portion 3B from expanding in the contracted state. In addition, since the second portion 5A disposed in the expansion portion 3B is not stretched in a curved blood vessel, the ability of the balloon 3 to follow the curved blood vessel can be improved.

[0079] The bottoms of the slits 7A to 7C, in other words, the parts of the slits 7A to 7C that are closest to the central axis C1, may be located radially outward from the bottom surface 503 (see FIG. 1) of the second portion 5A. This allows the second portion 5A to effectively function as a tension rod when the deflated balloon 3 is inserted into a blood vessel. In FIG. 7, only some of the slits 7A, 7B, and 7C may be provided in the second portion 5A. For example, the slit 7B may be provided only in the second portion 5A of the inflation portion 3B of the balloon 3, and the slits 7A and 7C may not be provided in the second portions 5A of the distal end connecting portion 3A and the proximal end connecting portion 3C.

[0080] <Balloon Catheter 1F> Figure 8 shows the process in which the balloon 3 of the balloon catheter 1F changes from an expanded state to a contracted state. Assume that compressed fluid is removed from the balloon 3 in the expanded state shown in Figure 8(A). In response to the removal of the compressed fluid, the balloon 3 changes from the expanded state to the contracted state.

[0081] As shown in FIG. 8(B), in the process of the balloon 3 changing from an inflated state to a deflated state, the second portions 51A-53A move toward the central axis C1 before the first portions 41A-43A. The first portions 41A-43A are pushed outward except for both ends in the circumferential direction E1 (see FIG. 1), and protrude outward from the imaginary circle S. As shown in FIG. 8(C), the first portion 41A has a maximum curvature at the vertex P(1). The first portion 42A has a maximum curvature at the vertex P(2). The first portion 43A has a maximum curvature at the vertex P(3).

[0082] As shown in FIG. 9, a virtual plane extending from the central axis C1 through the apex P(1) of the first portion 41A in the radial direction is denoted as "W41". A virtual plane extending from the central axis C1 through the apex P(2) of the first portion 42A in the radial direction is denoted as "W42". A virtual plane extending from the central axis C1 through the apex P(3) of the first portion 43A in the radial direction is denoted as "W43". A virtual plane extending from the central axis C1 through the apex 500 of the second portion 51A in the radial direction is denoted as "W51". A virtual plane extending from the central axis C1 through the apex 500 of the second portion 52A in the radial direction is denoted as "W52". A virtual plane extending from the central axis C1 through the apex 500 of the second portion 53A in the radial direction is denoted as "W53".

[0083] A virtual plane that is equidistant from each of the planes W51 and W52, i.e., a virtual plane that bisects the angle between the planes W51 and W52, is referred to as "plane W410". A virtual plane that is equidistant from each of the planes W52 and W53, i.e., a virtual plane that bisects the angle between the planes W52 and W53, is referred to as "plane W420". A virtual plane that is equidistant from each of the planes W53 and W51, i.e., a virtual plane that bisects the angle between the planes W53 and W51, is referred to as "plane W430". The counterclockwise side of the circumferential direction E1 (see FIG. 1) in FIG. 9 is referred to as "one side E11 of the circumferential direction E1".

[0084] The angle between the planes W51 and W41, the angle between the planes W52 and W42, and the angle between the planes W53 and W43 are equal. Hereinafter, this angle is expressed as "θa". The angle between the planes W41 and W52, the angle between the planes W42 and W53, and the angle between the planes W43 and W51 are equal. Hereinafter, this angle is expressed as "θb". In this case, the angle θb is greater than the angle θa (θa<θb). That is, the vertex P(1) is disposed on one side E11 of the circumferential direction E1 with respect to the plane W410. The vertex P(2) is disposed on one side E11 of the circumferential direction E1 with respect to the plane W420. The vertex P(3) is disposed on one side E11 of the circumferential direction E1 with respect to the plane W430.

[0085] 9, only the angle θa between the planes W51 and W41 is shown, and the angle θa between the planes W52 and W42 and the angle θa between the planes W53 and W43 are omitted. Also, only the angle θb between the planes W41 and W52 is shown, and the angle θb between the planes W42 and W53 and the angle θb between the planes W43 and W51 are omitted.

[0086] Of the first part 41A, the part extending from the connection part with the second part 51A to the vertex P(1) is called the first extension part 411. Of the first part 41A, the part extending from the connection part with the second part 52A to the vertex P(1) is called the second extension part 412. Of the first part 42A, the part extending from the connection part with the second part 52A to the vertex P(2) is called the first extension part 421. Of the first part 42A, the part extending from the connection part with the second part 53A to the vertex P(2) is called the second extension part 422. Of the first part 43A, the part extending from the connection part with the second part 53A to the vertex P(3) is called the first extension part 431. Of the first part 43A, the part extending from the connection part with the second part 51A to the vertex P(3) is called the second extension part 432.

[0087] The lengths of the first extension parts 411, 421, and 431 are equal. Hereinafter, this length is denoted as "La". Also, the lengths of the second extension parts 412, 422, and 432 are equal. Hereinafter, this length is denoted as "Lb". In this case, the length Lb is longer than the length La (La < Lb). In FIG. 9, only the length La of the first extension part 421 is shown, and the lengths La of the first extension parts 411 and 431 are omitted. Also, only the length Lb of the second extension part 422 is shown, and the lengths Lb of the second extension parts 412 and 432 are omitted.

[0088] The distance between the vertex P(1) of the first part 41A and the vertex 500 of the second part 51A, the distance between the vertex P(2) of the first part 42A and the vertex 500 of the second part 52A, and the distance between the vertex P(3) of the first part 43A and the vertex 500 of the second part 53A are equal. Hereinafter, this distance is denoted as "Lc". The distance between the vertex P(1) of the first part 41A and the vertex 500 of the second part 52A, the distance between the vertex P(2) of the first part 42A and the vertex 500 of the second part 53A, and the distance between the vertex P(3) of the first part 43A and the vertex 500 of the second part 51A are equal. Hereinafter, this distance is denoted as "Ld". In this case, the distance Ld is longer than the distance Lc (Lc < Ld).

[0089] In FIG. 9, only the distance Lc between the vertex P(3) of the first part 43A and the vertex 500 of the second part 53A is shown, and the distances Lc between the vertex P(1) of the first part 41A and the vertex 500 of the second part 51A, and between the vertex P(2) of the first part 42A and the vertex 500 of the second part 52A are omitted. Also, only the distance Ld between the vertex P(3) of the first part 43A and the vertex 500 of the second part 51A is shown, and the distances Ld between the vertex P(1) of the first part 41A and the vertex 500 of the second part 52A, and between the vertex P(2) of the first part 42A and the vertex 500 of the second part 53A are omitted.

[0090] As shown in FIG. 8(D), with the second parts 51A to 53A moved to positions close to the inner tube 22, the first parts 41A to 43A are folded. Even in this state, the relationships of the lengths La and Lb (La < Lb), the relationships of the distances Lc and Ld (Lc < Ld), and the relationships of the angles θa and θb (θa < θb) described in FIG. 9 are maintained.

[0091] As shown in FIG. 8(E), the first parts 41A to 43A cover the second parts 51A to 53A from the outside in the folded state to form the blade parts 41B to 43B. Thereby, the balloon 3 is in a contracted state.

[0092] Here, the length Lb of the second extension part 412 of the first part 41A is longer than the length La of the first extension part 411 (La < Lb). The distance Ld between the vertex P(1) of the first part 41A and the vertex 500 of the second part 52A is longer than the distance Lc between the vertex P(1) of the first part 41A and the vertex 500 of the second part 51A (Lc < Ld). The vertex P(1) is arranged on one side E11 of the circumferential direction E1 with respect to the plane W410. Therefore, when the balloon 3 deforms from the inflated state to the contracted state, the first part 41A is likely to be arranged at a position close to the second part 51A adjacent to one side E11 of the circumferential direction E1. Similarly, the first part 42A is likely to be arranged at a position close to the second part 52A adjacent to one side E11 of the circumferential direction E1. The first part 43A is likely to be arranged at a position close to the second part 53A adjacent to one side E11 of the circumferential direction E1.

[0093] Therefore, in the balloon catheter 1F, the position of the first portion 4A in the process of the balloon 3 deforming from the inflated state to the contracted state is stabilized and is easily arranged at a position covering the second portion 5A. Accordingly, in the process of the balloon 3 deforming from the inflated state to the contracted state, the first portion 4A can easily cover the second portion 5A adjacent to one side E11 in the circumferential direction E1. Also, even when the balloon 3 repeatedly deforms between the inflated state and the contracted state, the balloon catheter 1F can appropriately cover the second portion 5A with the first portion 4A in the contracted state.

[0094] <Balloon catheter 1G> The shapes of the first portions 41A, 42A, and 43A in the process of the balloon 3 deforming from the inflated state to the contracted state of the balloon catheter 1G are different from those of the balloon catheter 1F. FIG. 10 shows the process of the balloon 3 of the balloon catheter 1G deforming from the inflated state to the contracted state. The states in FIGS. 10(A) and 10(B) are the same as those in FIGS. 8(A) and 8(B).

[0095] In the process of the balloon 3 deforming from the inflated state to the contracted state, the first portions 41A to 43A are pushed outwards and protrude outside the virtual circle S. As shown in FIG. 10(C), the curvature of the first portion 41A is maximum at the vertex P(1). The curvature of the first portion 42A is maximum at the vertex P(2). The curvature of the first portion 43A is maximum at the vertex P(3). The relationships of the lengths La and Lb (La < Lb) and the distances Lc and Ld (Lc < Ld) in the balloon 3 are the same as those in the case of the balloon catheter 1F (see FIG. 9) (see FIG. 11). Also, the positional relationships between the plane W410 and the vertex P(1), between the plane W420 and the vertex P(2), and between the plane W430 and the vertex P(3) are also the same as those in the case of the balloon catheter 1F (see FIG. 9) (see FIG. 11).

[0096] As shown in FIG. 11, a part of the first extension 411 of the first portion 41A (the part within the frame line Q41) is disposed on the side opposite to one side E11 of the circumferential direction E1 (see FIG. 1) with respect to the plane W41, that is, the side where the second portion 52A is located with respect to the plane W41 (hereinafter referred to as "the other side E12 of the circumferential direction E1"). A part of the first extension 421 of the first portion 42A (the part within the frame line Q42) is disposed on the other side E12 of the circumferential direction E1 with respect to the plane W42, that is, the side where the second portion 53A is located with respect to the plane W41. A part of the first extension 431 of the first portion 43A (the part within the frame line Q43) is disposed on the other side E12 of the circumferential direction E1 with respect to the plane W43, that is, the side where the second portion 51A is located.

[0097] A direction Y41 is defined which extends outside the balloon 3 orthogonally to the tangent of the first portion 41A at the vertex P(1) of the first portion 41A. The direction Y41 extends inclined with respect to the radial direction centered on the central axis C1 toward one side E11 of the circumferential direction E1. A direction Y42 is defined which extends outside the balloon 3 orthogonally to the tangent of the first portion 42A at the vertex P(2) of the first portion 42A. The direction Y42 extends inclined with respect to the radial direction centered on the central axis C1 toward one side E11 of the circumferential direction E1. A direction Y43 is defined which extends outside the balloon 3 orthogonally to the tangent of the first portion 43A at the vertex P(3) of the first portion 43A. The direction Y43 extends inclined with respect to the radial direction centered on the central axis C1 toward one side E11 of the circumferential direction E1.

[0098] As shown in FIG. 10(D), with the second portions 51A to 53A moved to positions close to the inner tube 22, the first portions 41A to 43A are folded. Even in this state, the relationships between the lengths La and Lb (La < Lb) and the relationships between the distances Lc and Ld (Lc < Ld) described in FIG. 11 are maintained. On the other hand, in FIG. 10(D), the planes W41 and W51 coincide, the planes W42 and W52 coincide, and the planes W43 and W53 coincide.

[0099] The first extension portion 411 of the first portion 41A is disposed over its entirety on the other side E12 (see FIG. 11) of the circumferential direction E1 with respect to the plane W41. The first extension portion 421 of the first portion 42A is disposed over its entirety on the other side E12 of the circumferential direction E1 with respect to the plane W42. The first extension portion 431 of the first portion 43A is disposed over its entirety on the other side E12 of the circumferential direction E1 with respect to the plane W43. The directions Y41, Y42, and Y43 (see FIG. 11) are each inclined toward one side E11 (see FIG. 11) of the circumferential direction E1 with respect to the radial direction.

[0100] 10(E), the first portions 41A to 43A in the folded state cover the second portions 51A to 53A from the outside, forming wing portions 41B to 43B, whereby the balloon 3 is in a deflated state.

[0101] Here, the apex P(1) of the first portion 41A is disposed on one side E11 of the circumferential direction E1 with respect to the plane W410. Also, a part of the first extension portion 411 is disposed on the other side E12 of the circumferential direction E1 with respect to the plane W41, and the direction Y41 is inclined toward the one side E11 of the circumferential direction E1 with respect to the plane W41. Therefore, when the balloon 3 is deformed from the inflated state to the deflated state, the first portion 41A is likely to be disposed in a position close to the second portion 51A adjacent to the one side E11 of the circumferential direction E1, and is likely to cover the second portion 51A from the radial outside. Similarly, the first portion 42A is likely to be disposed in a position close to the second portion 52A adjacent to the one side E11 of the circumferential direction E1, and is likely to cover the second portion 52A from the radial outside. The first portion 43A is likely to be disposed at a position close to the second portion 53A adjacent to one side E11 in the circumferential direction E1, and is likely to cover the second portion 53A from the outside in the radial direction.

[0102] That is, in the balloon catheter 1G, the position of the first portion 4A is stabilized during the process of the balloon 3 changing from the expanded state to the contracted state, and the first portion 4A is easily positioned to cover the second portion 5A adjacent to the one side E11 in the circumferential direction E1. Furthermore, in the balloon catheter 1G, the first portion 4A has a shape that easily covers the second portion 5A from the outside in the radial direction during the process of the balloon 3 changing from the expanded state to the contracted state. Therefore, the balloon catheter 1G can easily cover the second portion 5A adjacent to the one side E11 in the circumferential direction E1 with the first portion 4A. Furthermore, in the balloon catheter 1G, even if the balloon 3 changes repeatedly between the expanded state and the contracted state, the first portion 4A can appropriately cover the second portion 5A in the contracted state.

[0103] <Special notes regarding balloon catheters 1F and 1G> The lengths of the first extension portions 411, 421, and 431 may be different from each other. The lengths of the second extension portions 412, 422, and 432 may be different from each other. In this case, it is sufficient that the second extension portion 412 is longer than the first extension portion 411 in the first portion 41A. It is sufficient that the second extension portion 422 is longer than the first extension portion 421 in the first portion 42A. It is sufficient that the second extension portion 432 is longer than the first extension portion 431 in the first portion 43A.

[0104] The distance between the vertex P(1) of the first portion 41A and the vertex 500 of the second portion 51A, the distance between the vertex P(2) of the first portion 42A and the vertex 500 of the second portion 52A, and the distance between the vertex P(3) of the first portion 43A and the vertex 500 of the second portion 53A may be different from each other. The distance between the vertex P(1) of the first portion 41A and the vertex 500 of the second portion 52A, the distance between the vertex P(2) of the first portion 42A and the vertex 500 of the second portion 53A, and the distance between the vertex P(3) of the first portion 43A and the vertex 500 of the second portion 51A may be different from each other. In this case, it is only necessary that the distance between the vertex P(1) of the first portion 41A and the vertex 500 of the second portion 52A is longer than the distance between the vertex P(1) of the first portion 41A and the vertex 500 of the second portion 51A. It is only necessary that the distance between the vertex P(2) of the first portion 42A and the vertex 500 of the second portion 53A is longer than the distance between the vertex P(2) of the first portion 42A and the vertex 500 of the second portion 52A. It is only necessary that the distance between the vertex P(3) of the first portion 43A and the vertex 500 of the second portion 51A is longer than the distance between the vertex P(3) of the first portion 43A and the vertex 500 of the second portion 53A.

Claims

1. A catheter balloon that can be inflated or deflated in response to changes in internal pressure, an expansion portion that moves radially outward about a central axis extending in a predetermined extension direction and expands in a process of changing from the contracted state to the expanded state, and that becomes a cylindrical shape extending in the extension direction in the expanded state; a tip connecting portion that extends from a tip portion that is an end portion on one side in the extension direction of the expansion portion, and in the expanded state, a diameter of one end that is an end portion connected to the expansion portion is larger than a diameter of another end that is an end portion opposite to the one end; a base end connecting portion that extends from a base end that is the other end of the expansion portion in the extension direction, and in the expanded state, a diameter of one end that is an end that is connected to the expansion portion is larger than a diameter of the other end that is an end opposite to the one end; Equipped with At least the expansion portion is a plurality of first portions that form wings in the contracted state; In the expanded state, a plurality of second portions are adjacent to the plurality of first portions in a circumferential direction about the central axis, In the expanded state, the radial distance from the central axis to each of the plurality of second portions is shorter than the radial distance from the central axis to each of the plurality of first portions; Each of the second portions includes a rigid portion having a higher rigidity than the first portions, A catheter balloon, wherein a portion of the rigid portion protrudes outward beyond an outer surface of the first portion.

2. A catheter balloon that can be inflated or deflated in response to changes in internal pressure, an expansion portion that moves radially outward about a central axis extending in a predetermined extension direction and expands in a process of changing from the contracted state to the expanded state, and that becomes a cylindrical shape extending in the extension direction in the expanded state; a tip connecting portion that extends from a tip portion that is an end portion on one side in the extension direction of the expansion portion, and in the expanded state, a diameter of one end that is an end portion connected to the expansion portion is larger than a diameter of another end that is an end portion opposite to the one end; a base end connecting portion that extends from a base end that is the other end of the expansion portion in the extension direction, and in the expanded state, a diameter of one end that is an end that is connected to the expansion portion is larger than a diameter of the other end that is an end opposite to the one end; Equipped with At least the expansion portion is a plurality of first portions that form wings in the contracted state; In the expanded state, a plurality of second portions are adjacent to the plurality of first portions in a circumferential direction about the central axis, In the expanded state, the radial distance from the central axis to each of the plurality of second portions is shorter than the radial distance from the central axis to each of the plurality of first portions; In the expanded state, A catheter balloon, characterized in that at least the outer surface of the expansion portion is formed with recesses in which the plurality of second portions are recessed toward the central axis.

3. The plurality of second portions are 3. The catheter balloon according to claim 1, wherein, in the process of changing from the expanded state to the contracted state, the first portions move toward the central axis ahead of the first portions, thereby forming a depression recessed toward the central axis.

4. the distal end coupling portion and the proximal end coupling portion each have the plurality of first portions and the plurality of second portions, Each of the plurality of first portions and the plurality of second portions includes 4. The catheter balloon according to claim 1, wherein the catheter balloon extends in the stretching direction from the other end of the tip connecting portion to the other end of the base connecting portion.

5. the distal end coupling portion and the proximal end coupling portion each have the plurality of first portions and the plurality of second portions, Each of the plurality of first portions and the plurality of second portions includes The distal end connecting portion extends from the other end to the other end of the proximal end connecting portion along the extension direction, 4. The catheter balloon according to claim 3, wherein the amount of the depression formed in the process of changing from the expanded state to the contracted state is larger in the expansion portion than in the distal end connecting portion and the proximal end connecting portion.

6. The catheter balloon according to claim 2 , wherein each of the second portions includes a rigid portion having a higher rigidity than the first portions.

7. 7. The catheter balloon according to claim 1, wherein the radial thickness of each of the second portions is greater than the radial thickness of each of the first portions.

8. 8. The catheter balloon according to claim 7, wherein in the inflated state, a distance between an inner surface of the second portions and the central axis is shorter than a distance between an inner surface of the first portions and the central axis.

9. 9. The catheter balloon according to claim 7, wherein in the inflated state, a distance between the outer surfaces of the second portions and the central axis is longer than a distance between the outer surfaces of the first portions and the central axis.

10. 10. The catheter balloon according to claim 1, wherein the outer surfaces of the second portions are rounded.

11. 11. The catheter balloon according to claim 1, wherein the second portions are arranged at equal intervals in the circumferential direction.

12. 12. The catheter balloon according to claim 1, wherein the shape of the second portions is memorized in a state in which depressions recessed toward the central axis are formed in the second portions.

13. 13. The catheter balloon according to claim 1, wherein the first portions and the second portions are made of the same material.

14. 6. The catheter balloon according to claim 4, wherein one or more slits are provided in the portion of the second portions arranged at the tip connecting portion.

15. 6. The catheter balloon according to claim 4, wherein one or more slits are provided in the portion of the second portions disposed at the base end connecting portion.

16. 16. The catheter balloon according to claim 1, wherein one or more slits are provided in the portion of the second portions that is disposed in the inflation portion.

17. Each of the plurality of first portions comprises: a vertex at which the curvature is maximum during the process of transformation from the expanded state to the contracted state; a first extension portion extending from a connection portion with the second portion adjacent to one side in the circumferential direction to the apex; a second extension portion extending from a connection portion with the second portion adjacent to the other side in the circumferential direction to the apex; having 17. The catheter balloon according to claim 1, wherein the second extension portion has a length longer than the first extension portion.

18. Each of the plurality of first portions comprises: a vertex at which a curvature is maximized during the process of deformation from the expanded state to the contracted state; 17. The catheter balloon according to claim 1, wherein, during a process of deformation from the expanded state to the contracted state, a distance between the apex and the second portion adjacent to the first portion having the apex on the other circumferential side is longer than a distance between the apex and the second portion adjacent to the first portion having the apex on one circumferential side.

19. Each of the plurality of first portions comprises: a vertex at which the curvature is maximum during the process of transformation from the expanded state to the contracted state; a first extension portion extending from a connection portion with the second portion adjacent to one side in the circumferential direction to the apex; a second extension portion extending from a connection portion with the second portion adjacent to the other side in the circumferential direction to the apex; having 17. The catheter balloon according to claim 1, wherein, during a process of deformation from the expanded state to the contracted state, at least a part of the first extension portion of the first section having the apex is located on the other side in the circumferential direction with respect to an imaginary plane that passes through the central axis and the apex and extends in the radial direction.

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