Balloon catheter

Abstract

To provide a balloon catheter capable of suppressing direct contact of a balloon with heating members.SOLUTION: A balloon catheter includes a shaft 12 to be inserted into a body, a balloon 14 provided at a distal end side of the shaft 12 and inflatable by a fluid supplied from a proximal end side of the shaft 12, heating members 16A and 16B fixed to the shaft 12 in the balloon 14 and heating the fluid, and projections 50A and 50B provided integrally with the shaft 12 or on the shaft 12 and coming close to or into contact with the heating members 16A and 16B, where the projections 50A and 50B include high parts 52 located at positions radially higher than at least parts of outer peripheral surfaces of the heating members 16A and 16B.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to balloon catheters. [Background technology]

[0002] Patent document 1 discloses a balloon catheter including a shaft to be inserted into the body, a balloon provided at the tip portion of the shaft, and a heating member fixed to the shaft within the balloon and for heating a fluid supplied into the balloon. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-130428 A Summary of the Invention [Problem to be solved by the invention]

[0004] In order to effectively heat the fluid inside the balloon with the heating element, it is desirable to prevent the balloon from coming into direct contact with the heating element as much as possible so as not to impede the heating of the fluid by the heating element.

[0005] Therefore, one object of the present disclosure is to provide a balloon catheter that can prevent the balloon from coming into direct contact with the heating member. [Means for solving the problem]

[0006] The balloon catheter of the present disclosure comprises a shaft to be inserted into the body, a balloon provided at a tip end portion of the shaft and expandable by fluid supplied from a base end side of the shaft, a heating member fixed to the shaft within the balloon and for heating the fluid, and a protrusion provided integrally with or on the shaft and in close proximity to or in contact with the heating member, the protrusion having a higher portion that is positioned radially higher than at least a portion of the outer circumferential surface of the heating member. Effect of the Invention

[0007] According to the present disclosure, direct contact of the balloon with the heating member can be suppressed. [Brief description of the drawings]

[0008] [Figure 1] 1 is an overall view of a balloon catheter according to an embodiment of the present invention. [Diagram 2] 1 is a cross-sectional view showing the balloon of the present embodiment together with the surrounding structure. [Diagram 3] FIG. 3 is an enlarged view of a portion of FIG. [Figure 4] 10A and 10B are explanatory diagrams relating to the effect of the protrusions of the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment for implementing the balloon catheter of the present disclosure will be described. The same or equivalent elements are given the same reference numerals, and duplicated explanations will be omitted. In each drawing, for the convenience of explanation, components are omitted, enlarged, or reduced as appropriate. The drawings should be viewed according to the orientation of the reference numerals. In this specification, "contact," "fixation," and "adhesion" include cases where the conditions mentioned are directly satisfied by two elements, as well as cases where the conditions are indirectly satisfied via other elements, unless otherwise specified.

[0010] First, an overview of the balloon catheter 10 of this embodiment will be described. See FIG. 2. The balloon catheter 10 of this embodiment is an ablation balloon catheter that is used by heating a fluid (not shown) supplied into the balloon 14 with heating members 16A and 16B. In this balloon catheter 10, the surface temperature of the balloon 14 is adjusted by adjusting the temperature of the fluid in the balloon 14 by heating with the heating members 16A and 16B. Treatment (e.g., ablation of the biological tissue) is performed by the balloon catheter 10 by bringing the balloon 14, whose surface temperature has been adjusted in this manner, into contact with biological tissue.

[0011] Please refer to Fig. 3. The balloon catheter 10 of this embodiment includes protrusions 50A, 50B that are integral with or provided on the shaft 12 and are in close proximity to or in contact with the heating members 16A, 16B. The protrusions 50A, 50B include elevated portions 52 that are located radially higher than at least a portion of the outer circumferential surfaces of the heating members 16A, 16B.

[0012] Refer to FIG. 4. Let us assume that the balloon 14 approaches the outer circumferential surface of the heating members 16A and 16B in the radial direction. The approach of the balloon 14 may occur, for example, when the balloon 14 is brought into contact with biological tissue for ablation of the biological tissue. In particular, such an approach of the balloon 14 is likely to occur when the balloon 14 arranged in a bent portion of a hollow organ is brought into contact with the inner luminal surface on the outside of the bend. At this time, the balloon 14 is deformed, and at least one of the balloon 14 and the heating members 16A and 16B moves, so that the balloon 14 approaches relatively toward the heating members 16A and 16B.

[0013] According to this embodiment, when the balloon 14 tries to approach the heating members 16A and 16B relatively in this way, the high parts 52 of the protrusions 50A and 50B come into contact with the balloon 14, thereby preventing the approach. In addition, compared to the case where the protrusions 50A and 50B are not provided, the direct contact of the balloon 14 with the heating members 16A and 16B can be suppressed. As a result, the heating of the fluid by the heating members 16A and 16B is less likely to be hindered by the balloon 14, and the fluid in the balloon 14 can be effectively heated by the heating members 16A and 16B. For example, when the fluid in the balloon 14 is directly heated by the heating members 16A and 16B by direct resistance heating or the like, the direct contact of the balloon 14 with the heating members 16A and 16B is suppressed, so that the heating members 16A and 16B can effectively directly heat a wide range of the fluid in the balloon 14. In addition, when the fluid within the balloon 14 is indirectly heated by the heat generated by the heating elements 16A, 16B, such as by indirect resistance heating, by suppressing direct contact of the balloon 14 with the heating elements 16A, 16B, it becomes easier to effectively heat a wide area of ​​the fluid within the balloon 14 by heat transfer from the heating elements 16A, 16B to the fluid.

[0014] Please refer to FIG. 1. The balloon catheter 10 of the embodiment will now be described in detail. The balloon catheter 10 is used for treatment of a living body. Here, "treatment" refers to an action related to medical treatment or examination of a living body. The balloon catheter 10 of the present embodiment is used for ablation of biological tissue, but may be used for other purposes. The organs to be treated by the balloon catheter 10 are not particularly limited, and may be, for example, various organs such as circulatory organs such as the heart and blood vessels, as well as digestive organs such as the intestine and the hepatic duct.

[0015] The balloon catheter 10 comprises a shaft 12, at least the distal end portion of which is inserted into the body, a balloon 14 provided at the distal end portion of the shaft 12, heating members 16A, 16B for heating a fluid supplied into the balloon 14, and a handle 18 attached to the proximal end portion of the shaft 12. The handle 18 is held by an operator such as a doctor. In this specification, the direction along the axis of the shaft 12 is simply referred to as the "axial direction", and the radial and circumferential directions of a circle centered on the axis of the shaft 12 are simply referred to as the "radial direction" and the "circumferential direction".

[0016] Please refer to Fig. 2. The shaft 12 has flexibility allowing bending deformation. The shaft 12 is composed of at least one shaft member 20A, 20B. The shaft 12 of this embodiment includes an outer shaft member 20A and an inner shaft member 20B as the shaft members 20A, 20B. The outer shaft member 20A is formed with a main lumen 22 through which the inner shaft member 20B is inserted. The inner shaft member 20B is formed with an inner lumen 26 for inserting a medical device such as a guidewire.

[0017] A fluid passage lumen 28 through which the fluid supplied to the inside of the balloon 14 flows is formed in the shaft 12. The main lumen 22 of the outer shaft member 20A also serves as the fluid passage lumen 28 in this embodiment.

[0018] The balloon 14 can be expanded by a fluid supplied from the base end side of the shaft 12. FIG. 2 shows the balloon 14 in an expanded state. In this specification, unless otherwise specified, the relationship between various components will be described on the assumption that the balloon 14 is in an expanded state. The fluid for expanding the balloon 14 flows from an inflow port 18a (see FIG. 1) provided in the handle 18 into the fluid flow lumen 28 of the shaft 12, and is supplied to the balloon 14 via the fluid flow lumen 28. Here, the fluid will be described using a contrast medium as an example. A specific example of the fluid is not particularly limited as long as it can be heated by the heating members 16A and 16B. The fluid may be, for example, a contrast medium, a physiological saline solution, sterilized water, or other liquid, or may be a gas such as air.

[0019] The balloon 14 includes an expansion section 14a that can be expanded by a fluid, and a proximal sleeve section 14b and a distal sleeve section 14c that are provided on both axial sides of the expansion section 14a. The expansion section 14a expands so as to bulge radially outward relative to the sleeve sections 14b and 14c. The expansion section 14a in this embodiment includes a cylindrical body section 14d that extends straight in the axial direction, and a tapered section 14e that is provided on both axial sides of the body section 14d and that reduces in diameter as it moves axially outward from the body section 14d. The proximal sleeve section 14b is cylindrical and surrounds the shaft 12, and is attached to a part of the shaft 12 (here, the outer shaft member 20A) at its proximal end portion by welding, adhesion, or the like. The distal sleeve section 14c is cylindrical and surrounds the shaft 12, and is attached to a part of the shaft 12 (here, the inner shaft member 20B) by welding, adhesion, or the like. The shape of the expansion portion 14a of the balloon 14 is not particularly limited, and may be, for example, spherical.

[0020] The heating members 16A and 16B are fixed to the shaft 12 inside the balloon 14. In this embodiment, the heating members 16A and 16B are configured as electrodes that heat the fluid by direct resistance heating. The heating members 16A and 16B serving as electrodes heat the fluid by passing a current supplied from an external power supply device (not shown) through the fluid inside the balloon 14. The heating mode of the heating members 16A and 16B is not particularly limited, and the fluid may be heated by indirect resistance heating, ultrasonic heating, laser heating, microwave heating, or the like.

[0021] The entire heating members 16A and 16B are provided on one side of the axial center position Pa of the expansion portion 14a of the balloon 14. The heating members 16A and 16B are not provided on the axial center position Pa. The heating members 16A and 16B of this embodiment include a first heating member 16A whose entirety is provided on the axial tip side of the center position Pa, and a second heating member 16B whose entirety is provided on the axial base side of the center position Pa. This allows the first and second heating members 16A and 16B to heat the fluid over a wide axial range in the expansion portion 14a of the balloon 14. The first and second heating members 16A and 16B function as bipolar electrodes that pass electricity between each other.

[0022] Please refer to FIG. 2 and FIG. 3. The heating members 16A and 16B are ring-shaped and surround the shaft 12, forming a ring electrode. The shape of the heating members 16A and 16B is not limited to this, and may be linear, plate-shaped, or the like. The heating members 16A and 16B have an outer end 16a located on the axially outer side of the expansion part 14a of the balloon 14, and an inner end 16b located on the axially inner side of the expansion part 14a. The axially outer side here refers to the side that is axially away from the axial center position Pa of the expansion part 14a of the balloon 14, and the axially inner side refers to the side that is axially closer to the center position Pa. The heating members 16A and 16B are provided at both ends 16a and 16b with outer edge portions 16c located radially outward from the outer circumferential surface of the shaft 12. The outer edge portion 16c is formed at a corner portion between a side surface 16f facing the axial direction of the heating members 16A and 16B and an outer peripheral surface 16g facing radially outward. In addition, the heating members 16A and 16B have an exposed surface 16d that is not covered by the protrusions 50A and 50B (covering portions 56 described later) and is exposed to the internal space 14f of the balloon 14.

[0023] The heating members 16A and 16B are fixed to a part of the shaft 12 (here, the inner shaft member 20B) by adhesion using an adhesive 40. To achieve this, a ring-shaped inner gap 42 is provided between the inner periphery of the ring-shaped heating members 16A and 16B and the shaft 12, and the adhesive 40 is provided so as to fill the inner gap 42. The manner in which the heating members 16A and 16B are fixed to the shaft 12 is not limited to this. For example, the heating members 16A and 16B may be fixed to the shaft 12 by adhesion without leaving the ring-shaped inner gap 42, or may be fixed by swaging or the like.

[0024] The balloon catheter 10 includes a conductor 44 for electrically connecting the heating members 16A, 16B to an external power supply device. The conductor 44 is provided individually for each heating member 16A, 16B. The end of the conductor 44 is partially disposed in the inner gap 42 on the inner periphery side of the heating members 16A, 16B and is electrically connected to the heating members 16A, 16B. This allows the end of the conductor 44 to be protected by the heating members 16A, 16B, which contributes to ensuring electrical connection reliability. In addition, the conductor 44 may be electrically connected to the surface of the heating members 16A, 16B exposed to the internal space 14f of the balloon 14. The conductor 44 is drawn out from the adhesive 40 in the balloon 14 and extends into the handle 18 through the inside of the shaft 12 (the main lumen 22 of the outer shaft member 20A in this case) (not shown).

[0025] Here, the balloon catheter 10 includes protrusions 50A, 50B that are integral with the shaft 12 or that are provided on the shaft 12. Here, "integrally provided with the shaft 12" means that the protrusions 50A, 50B are integrally formed with a part of the shaft 12 (shaft member). Here, "provided on the shaft 12" means that the protrusions 50A, 50B are provided separately from the shaft 12 on a part of the surface of the shaft 12 (the outer peripheral surface of the shaft member). In providing the protrusions 50A, 50B on the shaft 12 in this manner, in addition to the case where the protrusions 50A, 50B are directly located on the shaft 12, the case where the protrusions 50A, 50B are indirectly located on the shaft 12 via other members (heating members 16A, 16B, adhesive 40, etc.) is included. In the present embodiment, the protrusions 50A, 50B are partially located directly on the shaft 12, and partially located indirectly on the shaft 12 via the heating members 16A, 16B and adhesive 40. In order to satisfy the condition of being integral with the shaft 12 or provided on the shaft 12, the protrusions 50A, 50B and the balloon 14 are separated so as to be freely movable without being restricted by each other.

[0026] The protrusions 50A and 50B are formed as protrusions protruding from the surface of at least one of the shaft 12 and the heating members 16A and 16B. In this embodiment, the protrusions are formed as protrusions protruding from the surfaces (specifically, the outer circumferential surfaces) of both the shaft 12 and the heating members 16A and 16B, but may be formed as protrusions protruding from the surface of only one of the shaft 12 and the heating members 16A and 16B. The surface here refers to the surface exposed to the internal space 14f of the balloon 14.

[0027] The protrusions 50A, 50B of this embodiment are formed by the adhesive 40 that bonds the heating members 16A, 16B to the shaft 12. Therefore, the structure of the balloon catheter 10 can be simplified compared to the case where the protrusions 50A, 50B are provided separately from the adhesive 40. For example, the adhesive 40 may be a photocurable adhesive that is cured by ultraviolet light or visible light, or a thermosetting adhesive that melts when heated and hardens when cooled. Specific examples of this adhesive include a urethane adhesive, an epoxy adhesive, a cyanoacrylate adhesive, and a silicone adhesive. In providing the protrusions 50A, 50B separately from the shaft 12, specific examples of the protrusions 50A, 50B are not limited to these, and may be formed of a wire material, a ring material, a mesh material, or the like. The concept of the protrusions 50A, 50B excludes the conductive wire 44.

[0028] The protrusions 50A, 50B are in contact with the heating members 16A, 16B. Alternatively, the protrusions 50A, 50B may be in close proximity to the heating members 16A, 16B. Here, "in close proximity" means that the protrusions 50A, 50B are near the heating members 16A, 16B. To satisfy the condition of "in close proximity", the protrusions 50A, 50B may be located in a position that can prevent the balloon 14 from approaching the heating members 16A, 16B when the balloon 14 tries to approach the heating members 16A, 16B in the radial direction. This position refers to, for example, a position where the minimum distance of the protrusions 50A, 50B to the heating members 16A, 16B is within 0.5 mm.

[0029] The protrusions 50A, 50B are provided at intervals corresponding to one heating member 16A, 16B, and are in close proximity to or in contact with the corresponding heating member 16A, 16B. In this embodiment, the protrusions 50A, 50B corresponding to one heating member 16A, 16B are provided at intervals in the axial direction, but may be provided at intervals in either the axial direction or the circumferential direction depending on the shape of the heating member 16A, 16B. The number of the protrusions 50A, 50B corresponding to one heating member 16A, 16B is two here, but may be three or more. As a result, the direct contact of the balloon 14 with the one heating member 16A, 16B can be effectively suppressed by the high portion 52 of the protrusions 50A, 50B, compared to the case where the number of the protrusions 50A, 50B corresponding to one heating member 16A, 16B is only one.

[0030] A plurality of protrusions 50A, 50B corresponding to one heating element 16A, 16B are provided individually corresponding to both ends 16a, 16b on both axial sides of one heating element 16A, 16B. The protrusions 50A, 50B include an outer protrusion 50A corresponding to the outer end 16a and an inner protrusion 50B corresponding to the inner end 16b. The protrusions 50A, 50B are adjacent to or in contact with the ends 16a, 16b of the corresponding heating elements 16A, 16B. The outer protrusions 50A are adjacent to or in contact with the outer end 16a of the heating elements 16A, 16B, and the inner protrusions 50B are adjacent to or in contact with the inner end 16b of the heating elements 16A, 16B. This makes it possible to prevent the balloon 14 from directly contacting the ends 16a, 16b of the heating members 16A, 16B by the high parts 52 of the protrusions 50A, 50B corresponding to the ends 16a, 16b. In addition, when the balloon 14 approaches the axial middle part of the heating members 16A, 16B, it can effectively prevent the balloon 14 from relatively approaching the middle part by contacting the high parts 52 of the protrusions 50A, 50B at two points. This is further effective in preventing the balloon 14 from directly contacting the heating members 16A, 16B over a wide range.

[0031] The protrusions 50A, 50B are provided individually corresponding to the first and second heating members 16A, 16B, respectively (see FIG. 2). There are a total of four protrusions 50A, 50B corresponding to the first and second heating members 16A, 16B, respectively. The protrusions 50A, 50B include a total of two outer protrusions 50A corresponding to the outer end portions 16a of the first and second heating members 16A, 16B.

[0032] When the expansion part 14a of the balloon 14 is delivered to the target position of the biological organ by a delivery catheter or the like, it comes into contact with the inner cavity surface of the biological organ, and is easily deformed radially inward at a location near the axial end. Therefore, the outer end 16a of the heating members 16A, 16B located near the axial end of the expansion part 14a of the balloon 14 is in a position where the balloon 14 is likely to approach the radially inward as the balloon 14 deforms (a position where direct contact is likely to occur) compared to the inner end 16b. The outer protrusion 50A corresponding to the outer end 16a of the heating members 16A, 16B located in such a position can suppress direct contact of the balloon 14 with the outer end 16a of the heating members 16A, 16B located in such a position. In particular, the outer protrusion 50A of this embodiment is provided individually corresponding to the outer end 16a of each of the first and second heating members 16A, 16B. This is more effective in that the individual outer protrusions 50A can prevent the balloon 14 from coming into direct contact with the outer ends 16a of the first and second heating members 16A and 16B. By preventing the balloon 14 from coming into direct contact with the ends 16a of the heating members 16A and 16B in this way, it is advantageous in that the balloon 14 can be prevented from getting caught on the heating members 16A and 16B as described below.

[0033] The protrusions 50A and 50B have high-level portions 52 located at a radially higher position than at least a part of the outer circumferential surface of the corresponding heating members 16A and 16B. Here, "high in the radial direction" means that the height is high (the radial distance is long) when the radial distance with respect to the axis C12 of the shaft 12 is taken as the height. The high-level portions 52 are located at a radially higher position than at least a part of the outer circumferential surface of the heating members 16A and 16B in a cross section cut along the axial direction. At least a part (here, the whole) of the high-level portions 52 in this embodiment is located at a higher position than the maximum height position Pb on the outer circumferential surface of the heating members 16A and 16B. Here, the maximum height position Pb refers to the radial position where the height on the outer circumferential surface of the heating members 16A and 16B is maximum. The protrusions 50A and 50B are formed with curved surface portions 54 whose height gradually increases toward the axially inner side of the corresponding heating members 16A and 16B.

[0034] When the balloon 14 approaches the heating members 16A and 16B corresponding to the protrusions 50A and 50B in the radially inward direction, the high-positioned portion 52 comes into contact with the balloon 14 before a part of the heating members 16A and 16B, thereby preventing the balloon 14 from approaching the heating members 16A and 16B (see FIG. 4). This makes it possible to prevent the balloon 14 from directly contacting the heating members 16A and 16B corresponding to the protrusions 50A and 50B. To achieve this, it is sufficient for the high-positioned portion 52 of the protrusions 50A and 50B to be able to prevent the balloon 14 from directly contacting a part of the outer circumferential surface of the heating members 16A and 16B, and it is not essential to prevent the balloon 14 from directly contacting the entire outer circumferential surface.

[0035] The high portion 52 is provided around the entire circumference about the axis of the shaft 12. By satisfying this condition, the effect of preventing the approach of the balloon 14 by the high portion 52 can be obtained regardless of the circumferential position of the protrusions 50A, 50B.

[0036] The protrusions 50A and 50B include a covering portion 56 that covers the ends 16a and 16b on one axial side of the heating members 16A and 16B from the radially outer side, and a non-covering portion 58 that does not cover the heating members 16A and 16B from the radially outer side. It can also be said that the covering portion 56 is a portion that overlaps with the heating members 16A and 16B in the radial direction, and the non-covering portion 58 is a portion that does not overlap with the heating members 16A and 16B in the radial direction. The non-covering portion 58 is provided on the axially outer side of the heating members 16A and 16B (the axially opposite side from the axial center position of the heating members 16A and 16B) with respect to the ends 16a and 16b of the heating members 16A and 16B that are covered by the covering portion 56 of the protrusions 50A and 50B. The high-position portion 52 of the protrusions 50A and 50B in this embodiment is provided continuously with the covering portion 56 and the non-covering portion 58, respectively. The covering portion 56 can prevent the balloon 14 from coming into direct contact with the outer edge portions 16c at the ends 16a, 16b of the heating members 16A, 16B. When the outer edge portions 16c are provided at the ends 16a, 16b of the heating members 16A, 16B, direct contact of the balloon 14 with the outer edge portions 16c can cause the balloon 14 to get caught on the heating members 16A, 16B, so this is advantageous in that it can be prevented.

[0037] The axial range R56 of the covering portion 56 of the heating members 16A and 16B is shorter than the axial range R58 of the non-covering portion 58. This allows the axial range of the exposed surface 16d of the heating members 16A and 16B to be as wide as possible, compared with the case where the axial range R56 of the covering portion 56 is longer than the axial range R58 of the non-covering portion 58. The wider the axial range of the exposed surface 16d of the heating members 16A and 16B, the more advantageous it is in terms of improving the heating performance of the heating members 16A and 16B. Therefore, while the ends 16a and 16b of the heating members 16A and 16B are covered by the covering portion 56, the heating performance of the heating members 16A and 16B can be ensured.

[0038] The protrusions 50A and 50B have a maximum height Pc not in the non-covered portion 58 but in the covered portion 56. Here, the position of the maximum height Pc is indicated by a dot. The protrusions 50A and 50B are radially higher in the covered portion 56 than in the non-covered portion 58. As a result, compared to the case where the protrusions 50A and 50B have a maximum height Pc in the non-covered portion 58, the portion of the protrusions 50A and 50B having a maximum height Pc is provided at a position closer to the exposed surface 16d of the heating members 16A and 16B. Therefore, the portion of the protrusions 50A and 50B having a maximum height Pc can effectively prevent the balloon 14 from directly contacting the exposed surface 16d of the heating members 16A and 16B.

[0039] The protrusions 50A and 50B are softer than the heating members 16A and 16B. This means that the surface hardness of the heating members 16A and 16B is lower than that of the protrusions 50A and 50B. Here, "soft" means that the amount of deformation when a predetermined external load is applied is relatively large. To achieve this, the heating members 16A and 16B are made of a metal material, and the protrusions 50A and 50B (adhesive 40) are made of a resin material. This makes it possible to soften the impact when the balloon 14 directly contacts the protrusions 50A and 50B, compared to when the protrusions 50A and 50B are harder (having a higher surface hardness) than the heating members 16A and 16B, and effectively suppresses the balloon 14 from being caught by the protrusions 50A and 50B.

[0040] The outer circumferential surface of the shaft 12 includes an overlapping region 60 that overlaps with the heating members 16A, 16B in the radial direction, and a non-overlapping region 62 that does not overlap with the heating members 16A, 16B in the radial direction. The non-overlapping regions 62 are provided on both axial sides of the overlapping region 60. The overlapping region 60 and the non-overlapping region 62 are flush and continuous in the axial direction. To satisfy this condition, the overlapping region 60 and the non-overlapping region 62 may extend straight in the axial direction without changing their radial positions, or may extend at an angle toward the axial direction.

[0041] As a method for fixing the heating members 16A and 16B to the shaft 12, a method is known in which the heating members 16A and 16B are integrated by plastic deformation of the shaft 12 by swaging or the like. When this method is used, there is a problem that the cross-sectional area of ​​the inner lumen of the shaft 12 (here, the inner lumen 26 of the inner shaft member 20B) is reduced at the fixing points of the heating members 16A and 16B to the shaft 12. In this regard, according to the present embodiment, the overlapping region 60 and the non-overlapping region 62 of the shaft 12 are continuous and flush with each other, so that the cross-sectional area of ​​the inner lumen of the shaft 12 can be prevented from being reduced when fixing the heating members 16A and 16B to the shaft 12.

[0042] When the heating members 16A, 16B are fixed to the shaft 12 in this manner, another problem occurs in that the outer edge portions 16c of the heating members 16A, 16B are located radially outward of the outer circumferential surface of the shaft 12, which may cause the balloon 14 to get caught. Such catching of the balloon 14 can be suppressed by the protrusions 50A, 50B corresponding to the ends 16a, 16b of the heating members 16A, 16B described above. This is particularly advantageous in that it is possible to prevent the balloon 14 from getting caught by the outer edge portions 16c while avoiding a reduction in the cross-sectional area of ​​the inner lumen of the shaft 12.

[0043] In the above example, the protrusions 50A, 50B corresponding to the ends 16a, 16b of the heating members 16A, 16B on which the outer edge portions 16c are provided are brought into contact with the ends 16a to prevent the balloon 14 from getting caught on the outer edge portions 16c of the heating members 16A, 16B. Alternatively, the protrusions 50A, 50B corresponding to the ends 16a, 16b of the heating members 16A, 16B on which the outer edge portions 16c are provided may be provided close to the ends 16a, 16b.

[0044] Next, variations of each of the components described above will be described.

[0045] A specific example of the shaft 12 is not particularly limited. The shaft 12 may be composed of, for example, only one shaft member, or may be composed of three or more shaft members. A specific example of the shaft member to which the heating member is fixed is also not particularly limited. A location where the fluid flow lumen 28 is formed in the shaft 12 is not particularly limited. The fluid flow lumen 28 may be formed, for example, in the outer shaft member 20A separately from the main lumen 22.

[0046] The number of heating members 16A and 16B is not particularly limited, and may be one or three or more, in addition to the two as in the embodiment. The heating members 16A and 16B may function as monopolar electrodes that pass electricity between the return electrode plate outside the body. The heating members may be provided on the axial center position Pa of the extension part 14a. In providing the entire heating members 16A and 16B on one axial side of the axial center position Pa, the heating members 16A and 16B may include only one of the first heating member 16A and the second heating member 16B. When the heating members 16A and 16B include both the first heating member 16A and the second heating member 16B, the number of each of the first heating member 16A and the second heating member 16B may be at least one, and may be two or more. The heating members 16A and 16B may not be provided with an outer edge portion 16c. This assumes a case in which the heating members 16A, 16B are partially embedded in the shaft 12 by plastic deformation of the shaft 12, for example, by swaging or the like, so that the outer circumferential surfaces of the heating members 16A, 16B become flush with the outer circumferential surface of the shaft 12. It can also be said that the outer circumferential surface of the shaft 12 does not need to be continuous and flush with the overlapping region 60 and the non-overlapping region 62.

[0047] The locations where the heating members 16A, 16B are covered by the covering portions 56 of the protrusions 50A, 50B are not particularly limited, and may be the axial ends of the heating members 16A, 16B, or the axial middle portions of the heating members 16A, 16B. The high-position portions 52 of the protrusions 50A, 50B may be provided only in a partial circumferential range around the axis of the shaft 12. The same applies to the protrusions 50A, 50B themselves. The protrusions 50A, 50B may have at least one of the covering portion 56 and the non-covering portion 58. The protrusions 50A, 50B may have, for example, only the covering portion 56, or only the non-covering portion 58. The length relationship between the axial range R56 of the covering portion 56 of the protrusions 50A, 50B and the axial range R58 of the non-covering portion 58 is not particularly limited. For example, the axial range R56 of the covering portion 56 may be ≧ the axial range R58 of the non-covering portion 58. The protrusions 50A, 50B may have a maximum height at the uncovered portion 58 instead of at the covered portion 56. The protrusions 50A, 50B may be harder than the heating members 16A, 16B.

[0048] The protrusions 50A, 50B may be provided corresponding to only one of the ends 16a, 16b on both axial sides of the heating members 16A, 16B. The protrusions 50A, 50B may be provided corresponding to only the inner end 16b of the heating members 16A, 16B, or may be provided corresponding to only the outer end 16a. The protrusions 50A, 50B may be provided corresponding to only at least one of the heating members 16A, 16B among the multiple heating members 16A, 16B. For example, in the example of the embodiment, the protrusions 50A, 50B may be provided corresponding to only the heating members 16A, 16B on the base end side.

[0049] The above-mentioned embodiment and modified forms are examples. The technical ideas abstracted from these should not be interpreted as being limited to the contents of the embodiment and modified forms. The contents of the embodiment and modified forms are subject to many design changes, such as changes, additions, and deletions of components. In the above-mentioned embodiment, the contents subject to such design changes are emphasized by adding the notation "embodiment". However, design changes are also permitted even in contents without such notation. The hatching on the cross section of the drawing does not limit the material of the object to which the hatching is added. The structures and numerical values ​​referred to in the embodiment and modified forms naturally include those that can be considered to be the same when considering manufacturing errors, dimensional errors, etc. [Explanation of symbols]

[0050] 10...balloon catheter, 12...shaft, 14...balloon, 14a...extension portion, 16A...first heating member, 16B...second heating member, 16a...outer end portion, 16c...outer edge portion, 40...adhesive, 50A, 50B...protrusion portion, 52...high portion, 56...covered portion, 58...non-covered portion, 60...overlapping region, 62...non-overlapping region.

Claims

1. A shaft that is inserted into the body; a balloon provided at a distal end portion of the shaft and expandable by a fluid supplied from a proximal end side of the shaft; a heating member secured to the shaft within the balloon for heating the fluid; a protrusion integral with or provided on the shaft and in close proximity to or in contact with the heating element; A balloon catheter, wherein the protrusion portion has a high portion that is positioned radially higher than at least a portion of the outer circumferential surface of the heating member.

2. The balloon catheter according to claim 1 , wherein the high portion is provided around the entire axis of the shaft.

3. The balloon catheter according to claim 1 , wherein the protrusions are provided in a plurality of locations spaced apart from one another in correspondence with one of the heating members, and are in close proximity to or in contact with the corresponding heating member.

4. The balloon catheter according to claim 3 , wherein a plurality of the protrusions are provided at intervals in the axial direction corresponding to each of the heating members.

5. The balloon catheter according to claim 1 , wherein the protrusion portion includes a covering portion that covers an end portion on one axial side of the heating member from the radially outer side.

6. The protrusion portion includes a non-covering portion that does not cover the heating member from the radially outer side, The balloon catheter of claim 5 , wherein the axial extent of the covered portion is shorter than the axial extent of the uncovered portion.

7. The protrusion includes a covering portion that covers the heating member from the radially outer side and a non-covering portion that does not cover the heating member from the radially outer side, The balloon catheter according to claim 1 , wherein the protrusion has a maximum height at the covering portion.

8. The balloon has an expansion portion expandable by the fluid, The entire heating member is provided on one side of the axial center position of the extension portion, The balloon catheter according to claim 1 , wherein the protrusions are provided corresponding to the outer end of the heating member and are in close proximity to or in contact with the corresponding outer end.

9. the heating member includes a first heating member entirely provided on a tip side in the axial direction with respect to the central position, and a second heating member entirely provided on a base side in the axial direction with respect to the central position, The balloon catheter according to claim 8 , wherein the protrusions are provided individually corresponding to outer ends of the first heating member and the second heating member, and are adjacent to or in contact with the corresponding outer ends.

10. The balloon catheter according to claim 1 , wherein the protrusion is made of an adhesive that adheres the heating element to the shaft.

11. The balloon catheter according to claim 1 , wherein the protrusions are softer than the heating member.

12. An outer edge portion is provided at an end portion on one axial side of the heating member, the outer edge portion being located radially outward from an outer circumferential surface of the shaft, The balloon catheter according to claim 1 , wherein the protrusion is provided corresponding to an end of the heating member where the outer edge portion is provided, and is adjacent to or in contact with the end.

13. The outer circumferential surface of the shaft includes an overlapping region that overlaps with the heating member in a radial direction and a non-overlapping region that does not overlap with the heating member in a radial direction, The balloon catheter according to claim 1 , wherein the overlapping region and the non-overlapping region are flush and continuous in the axial direction.

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