Balloon catheter and method for manufacturing balloon catheter

Abstract

[Problem] To achieve both a rewrapping property and curving property of a balloon to reduce the profile when deflated and improve operability. [Solution] The present invention comprises: a shaft part 110 having a hollow shape; and a deflatable balloon 140 disposed radially outward of the shaft part 110. The balloon 140 has a leading end fusion section 141 fixed to the shaft part 110, and a leading end tapered section 142 positioned at the base end of the leading end fusion section 141. The leading end tapered section 142 has a first portion 142A and a second portion 142B positioned closer to the leading end side than the first portion 142A. The first portion 142A has a first blade part 151 that is curved in the circumferential direction in the deflated state of the balloon 140, and the second portion 142B does not have a blade part 150.

Description

Balloon catheter and method of manufacturing the same

[0001] The present invention relates to a balloon catheter and a method for manufacturing a balloon catheter.

[0002] Balloon catheters are widely known in the medical field for use in procedures to dilate lesions (such as strictures) formed in biological lumens. A balloon catheter includes a long shaft and a radially expandable balloon provided at the distal end of the shaft. The deflated balloon can be delivered to the lesion via a narrow biological lumen and then expanded to widen the lesion.

[0003] Patent Document 1 discloses a method for manufacturing a balloon catheter. A balloon manufactured by the method disclosed in Patent Document 1 is folded so that the balloon is disposed between a proximal sleeve and a distal sleeve, and a fold is formed in the region from the distal sleeve to the proximal sleeve.

[0004] US Patent Application Publication No. 2008 / 0312589

[0005] For example, in procedures using a balloon catheter, such as pre-dilation and post-dilation in a single lesion, treatment of multi-vessel lesions, and treatment of bifurcation lesions, the balloon may be expanded and contracted multiple times, such as by expanding once within the biological lumen and then contracting, moving to a lesion in a different location, and then expanding again.

[0006] However, if a balloon is repeatedly deformed from a folded state to an expanded state or from an expanded state to a folded state, it may be difficult for the balloon to shrink to its pre-expansion profile when deflated and folded.

[0007] In the balloon catheter of Patent Document 1, the folds formed from the distal end of the tapered distal end of the balloon in the longitudinal direction to the proximal end contribute to improved rewrapping, but also reduce bending in a direction perpendicular to the folds, which can reduce the operability of the balloon catheter when advancing through a blood vessel.

[0008] At least one embodiment of the present invention has been made in consideration of the above circumstances, and specifically, an object of the present invention is to provide a balloon catheter and a method for manufacturing a balloon catheter that achieves both rewrapping and bendability of the balloon, thereby reducing the profile during deflation and improving operability.

[0009] The above object of the present invention can be achieved by the following means (1) to (7).

[0010] (1) A balloon catheter having a hollow shaft portion and a deflatable balloon disposed radially outward of the shaft portion, wherein the balloon has a fused tip portion fixed to the shaft portion and a tapered tip portion located at the base end of the fused tip portion, the tapered tip portion having a first section and a second section located distal to the first section, the first section having wing portions curved in the circumferential direction when the balloon is in a deflated state, and the second section having no wing portions.

[0011] (2) The balloon catheter according to (1) above, wherein the distal tapered portion has a third portion between the first portion and the second portion, the first portion having a first wing portion as the wing portion when the balloon is in a deflated state, and the third portion having a second wing portion as the wing portion when the balloon is in a deflated state, and wherein a wing length A2 between the fold formed in the second wing portion and the apex of the second wing portion is shorter than a wing length A1 between the fold formed in the first wing portion and the apex of the first wing portion.

[0012] (3) The balloon catheter according to (1) or (2) above, wherein the length of the second portion in the longitudinal direction is shorter than the length of the tip fused portion in the longitudinal direction.

[0013] (4) A balloon catheter according to any one of (1) to (3) above, wherein the balloon has a straight portion continuous with the base end of the distal tapered portion, and the ratio of the film thickness of the straight portion to the film thickness of the distal tapered portion is 1:1.10 or more and 1:1.18 or less.

[0014] (5) The balloon catheter according to (4) above, wherein the ratio of the thickness of the straight portion to the thickness of the tapered distal portion is 1:1.10 or greater and less than 1:1.13.

[0015] (6) A method for manufacturing a balloon catheter, comprising the steps of: preparing a shaft portion; and a balloon having a folded shape at a tapered tip portion located at the base end of a fused tip portion to be fused to the shaft portion; arranging the balloon at the distal end of the shaft portion; applying heat to the distal end of the balloon to fuse the balloon to the shaft portion to form the fused tip portion; and using the heat applied to the distal end of the balloon to form a second portion that is located distal to a first portion having foldable wings that can be folded during an expansion / contraction operation, and does not have the wing portions.

[0016] (7) The method for manufacturing a balloon catheter described in (6) above, wherein the distal tapered portion has a third portion between the first portion and the second portion, the first portion having a first wing portion as the wing portion when the balloon is in a deflated state, and the third portion having a second wing portion as the wing portion when the balloon is in a deflated state, and the wing length A2 from the fold formed in the second wing portion to the apex of the second wing portion is shorter than the wing length A1 between the fold formed in the first wing portion and the apex of the first wing portion.

[0017] According to at least one embodiment of the present invention, the balloon catheter has a tapered distal end portion including a first section and a second section, which allows for both rewrapping and bending, thereby realizing easy passage due to a reduced profile and high operability due to improved bending. Therefore, in procedures that require repeated expansion and contraction operations, the balloon catheter of the present invention allows a single device to be used multiple times without replacing the device, thereby contributing to reducing the number of devices used during the procedure.

[0018] FIG. 1 is a schematic structural diagram of a balloon catheter according to the present embodiment; FIG. 2 is a schematic cross-sectional view of the periphery of the tip portion of the balloon catheter according to the present embodiment; FIG. 3 is a schematic cross-sectional view of the periphery of the tip tapered portion of the balloon catheter according to the present embodiment; FIG. 4 is a schematic cross-sectional view of a first portion formed in the tip tapered portion; FIG. 5 is a schematic cross-sectional view of a second portion formed in the tip tapered portion; FIG. 6 is a schematic cross-sectional view of a third portion formed in the tip tapered portion; FIG. 7 is a flowchart showing steps in a manufacturing method for a balloon catheter according to the present embodiment; and FIG. 8 is a schematic structural diagram showing an example of the configuration of a fusion device.

[0019] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The embodiments shown here are merely examples for embodying the technical idea of ​​the present invention and are not intended to limit the present invention. Furthermore, all other embodiments, examples, and operational techniques that can be conceived by those skilled in the art without departing from the spirit of the present invention are included in the scope and spirit of the present invention, as well as in the scope of the inventions set forth in the claims and their equivalents.

[0020] Furthermore, for the convenience of illustration and ease of understanding, the drawings attached to this specification may be represented schematically with the scale, aspect ratio, shape, etc. appropriately changed from the actual product, but these are merely examples and do not limit the interpretation of the present invention.

[0021] In the following description, when ordinal numbers such as "first" and "second" are used, unless otherwise specified, they are used for convenience and do not stipulate any particular order.

[0022] In addition, in this specification, the "distal side" refers to the distal side of the balloon catheter 100 where the balloon 140 is located, and the "proximal side" refers to the proximal side of the balloon catheter 100 where the hub 180 is located, which is the "proximal side" of the balloon catheter 100. Unless otherwise specified, the "distal portion" refers to a certain range including the tip (the most distal end) and its surroundings, and the "proximal end" refers to a certain range including the base end (the most proximal end) and its surroundings.

[0023] 1, the "longitudinal direction" refers to the direction along the central axis of the balloon catheter 100. The "radial direction" refers to the direction moving away from or toward the central axis in a cross section perpendicular to the axis (transverse cross section) with the central axis of the balloon catheter 100 as the reference axis. The "circumferential direction" refers to the rotational direction with the central axis of the balloon catheter 100 as the reference axis.

[0024] [Device Configuration] First, the configuration of the balloon catheter 100 according to this embodiment will be described.

[0025] As shown in Figures 1 and 2, the balloon catheter 100 is a medical device that expands a lesion, such as a stenosis, formed in a biological lumen by expanding a balloon 140 located at the tip of the shaft portion 110 at the lesion, thereby treating the lesion.

[0026] The balloon catheter 100 can be configured as a PTCA dilation balloon catheter used to widen a narrowed portion of a coronary artery, for example, but can also be configured as a catheter used for treating and improving narrowed portions formed in other biological organs, such as other blood vessels, bile ducts, tracheas, esophagus, other digestive tracts, urethras, ear and nose cavities, and other organs.

[0027] The balloon catheter 100 is configured as a so-called "rapid exchange catheter device" in which a guidewire port 111 through which a guidewire G is led out is provided near the distal end of the shaft portion 110. The balloon catheter 100 can also be configured as a so-called "over-the-wire catheter device" in which a guidewire lumen 121 is formed to extend from the distal end to the proximal end of the shaft portion 110.

[0028] The shaft portion 110 has an inner tube 120 having a guidewire lumen 121 through which a guidewire G is inserted, and an outer tube 130 having a pressurized medium lumen 131 through which a pressurized medium can flow between the inner tube 120 and the outer tube 130. The inner tube 120 is inserted into the outer tube 130, so that the shaft portion 110 has a double-tube structure in which the inner tube 120 and the outer tube 130 are concentrically arranged.

[0029] Examples of materials that can be used to form the inner tube 120 and the outer tube 130 include polyolefins such as polyethylene, polypropylene, ethylene-propylene copolymer, and ethylene-vinyl acetate copolymer, thermoplastic resins such as soft polyvinyl chloride, various rubbers such as silicone rubber and latex rubber, various elastomers such as polyurethane elastomer, polyamide elastomer, and polyester elastomer, and crystalline plastics such as polyamide, crystalline polyethylene, and crystalline polypropylene. These materials can also be blended with antithrombotic substances such as heparin, prostaglandin, urokinase, and arginine derivatives to create antithrombotic materials.

[0030] The balloon 140 is liquid-tightly and air-tightly joined to the distal end of the inner tube 120 by laser welding. The distal end of the balloon 140 is joined to the inner tube 120, and the proximal end is joined to the outer tube .

[0031] The balloon 140 has a space between it and the inner tube 120 through which a pressurized medium can flow. The balloon 140 expands when the pressurized medium flows into the space. When the balloon 140 expands, the balloon catheter 100 presses a portion of the balloon 140 against a narrowed portion formed in a biological lumen, thereby widening and expanding the narrowed portion.

[0032] As shown in FIG. 2 , the balloon 140 has a distal fused portion 141, which is a certain region extending from the distal end of the balloon 140 toward the proximal end and is fused to the inner tube 120; a distal tapered portion 142 arranged adjacent to the proximal end of the distal fused portion 141; a straight portion 143 arranged adjacent to the proximal end of the distal tapered portion 142; a proximal tapered portion 144 arranged adjacent to the proximal end of the straight portion 143; and a proximal fused portion 145 arranged adjacent to the proximal end of the proximal tapered portion 144 and fused to the outer tube 130.

[0033] The balloon 140 is formed with multiple wings 150 that protrude radially outward. The wings 150 are formed by a folding process during manufacturing that imparts a predetermined folded shape with creases 153. The wings 150 are formed by folding the balloon 140 circumferentially along the creases 153 that are formed at the base of the wings 150 during deflation. Here, "deflated" refers to the deflated state of the balloon 140 immediately after it is removed from its packaging container and before the pressurized medium is introduced during the procedure. Therefore, this does not include the deflated state when the balloon 140 is rewrapped during the procedure. There are no particular limitations on the number of wings 150, their spacing, cross-sectional shape (shape of a cross section perpendicular to the axis), etc.

[0034] For example, an organic polymer material can be used as the material for forming the balloon 140. Specifically, polymer materials such as polyolefin (e.g., polyethylene, polypropylene, polybutene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ionomer, or a mixture of two or more of these), polyvinyl chloride, polyamide, polyamide elastomer, polyurethane, polyurethane elastomer, polyimide, fluororesin, or a mixture of these, or an elastic resin material such as two or more of the above polymer materials can be used, and among these, polyamide-based resins can be preferably used as the main material.

[0035] A distal tip 160 can be attached to the distal end of the inner tube 120. The distal tip 160 prevents damage to a biological organ (such as the inner wall of a blood vessel) when the distal end of the balloon catheter 100 comes into contact with the biological organ. The distal tip can be made of a resin material that is more flexible than the inner tube 120.

[0036] The inner tube 120 may be provided with a radiopaque marker portion 170. The radiopaque marker portion 170 may be disposed, for example, at a position on the inner tube 120 that indicates the boundary with the distal end side of the balloon 140, and at a position on the inner tube 120 that indicates the boundary with the proximal end side of the balloon 140.

[0037] 1, a hub 180 can be provided at the base end of the shaft portion 110. The hub 180 can be connected in a liquid-tight and airtight manner to a supply device (not shown) such as an indeflator for supplying a pressurized medium.

[0038] The pressurized medium (e.g., saline, contrast medium, etc.) used to inflate the balloon 140 can be flowed into the pressurized medium lumen 131 of the shaft portion 110 via the internal space (lumen) of the hub 180. The pressurized medium is supplied to the space of the balloon 140 via the pressurized medium lumen 131.

[0039] A coating can be formed on the outer surface of the balloon 140. The coating can be, for example, a hydrophilic coating layer that improves the sliding properties of the balloon 140, or a drug coating layer that contains a predetermined drug. There are no particular restrictions on the specific materials that can be used to form the hydrophilic coating layer or drug coating layer.

[0040] 3, the balloon 140 according to this embodiment has four sections (first section 142A to third section 142C) in the region from the distal end to the proximal end of the distal tapered section 142, which are divided by the state of folds 153 formed during shaping. The first section 142A to third section 142C are located closer to the proximal end than the distal fused section 141, and therefore are not fused to the inner tube 120.

[0041] 3, the distal tapered section 142 has a first section 142A formed in a region extending from the base end toward the distal end, a second section 142B located closer to the distal end than the first section 142A, and a third section 142C formed between the first section 142A and the second section 142B. The balloon catheter 100 has the distal tapered section 142 formed with the first section 142A to the third section 142C, and therefore is able to achieve both rewrapability and bendability.

[0042] As shown in FIG. 3 , the first region 142A is a region of the distal tapered portion 142 where foldable wing portions 150 are formed during the expansion / contraction operation. In this embodiment, the first region is formed in a predetermined region extending from the base end of the distal tapered portion 142 toward the tip. As shown in FIG. 4A , the first region 142A has first wing portions 151 that function as wing portions 150. The first wing portions 151 have a wing length A1 that is the length from fold line 153 to the apex 154 of the first wing portions 151. The first region 142A allows the first wing portions 151 to fold along fold line 153 during deflation, thereby improving the rewrapping properties of the balloon catheter 100. The "outer outer peripheral surface 140a" is the surface that faces radially outward of the distal tapered portion 142 when the balloon 140 is deflated and the wing portions 150 are folded circumferentially, as shown in FIG. 4A .

[0043] As shown in FIG. 3 , the second section 142B is a section of the distal tapered section 142 that is located distally of the first section 142A and does not include foldable wing sections 150 during the expansion / contraction operation. In this embodiment, the second section 142B is formed in a predetermined region extending from the distal end of the distal tapered section 142 toward the proximal end. As shown in FIG. 4B , the second section 142B does not include folds 153 that act to fold the wing sections 150. The first section 142A improves the rewrapping properties of the distal tapered section 142, but this can reduce the flexibility of the folds 153 in a direction intersecting the longitudinal axis. In contrast, the second section 142B does not include folds 153, and therefore has a higher flexibility in a direction intersecting the longitudinal axis than the first section 142A. Therefore, the second section 142B contributes to improved maneuverability of the balloon catheter 100 within a blood vessel.

[0044] 3, the third portion 142C is located between the first portion 142A and the second portion 142B and has a second wing portion 152 that functions as the wing portion 150. The second wing portion 152 has a wing length A2 that is the length from the fold 153 to the apex 155 of the second wing portion 152. The wing length A2 of the second wing portion 152 is shorter than the wing length A1 of the first wing portion 151.

[0045] 3, third portion 142C is disposed such that its distal end is adjacent to the proximal end of second portion 142B and its proximal end is adjacent to the distal end of first portion 142A. Third portion 142C is a region in distal tapered portion 142 where a transition occurs between second portion 142B and first portion 142A from "without wings 150" to "with wings 150."

[0046] Since the third portion 142C has a length A2 that is shorter than the blade length A1 of the first blade portion 151 formed in the first portion 142A, it has a higher degree of curvature in the direction intersecting the longitudinal axis compared to the first portion 142A, and the curvature is slightly lower than that of the second portion 142B that does not have the fold 153.

[0047] As described above, distal tapered section 142 has second section 142B, which does not have wing sections 150, formed distally of first section 142A, which has wing sections 150 (first wing sections 151). First section 142A ensures rewrapping during expansion and contraction operations, while second section 142B increases the bendability of distal tapered section 142, improving maneuverability within a blood vessel.

[0048] The balloon catheter 100 also has a third section 142C between the first section 142A and the second section 142B, in which second wing sections 152 having a wing length A2 shorter than the wing length A1 of the first wing sections 151 formed in the first section 142A are formed. The third section 142C has greater flexibility in a direction intersecting the longitudinal axis than the first section 142A. Therefore, the balloon catheter 100 ensures rewrapping during expansion and contraction operations by the first section 142A and the third section 142C, while the second section 142B further increases the flexibility of the distal end of the distal tapered section 142, thereby ensuring maneuverability within a blood vessel. Furthermore, the third portion 142C has a second blade portion 152 having a blade length A2 that is shorter than the blade length A1 of the first blade portion 151 formed in the first portion 142A, and therefore, although the effect is less than that of the second portion 142B, it can contribute to improving the flexibility.

[0049] From the viewpoint of blood vessel passageability due to a reduced profile, it is preferable that the length of the second portion 142B in the longitudinal direction of the balloon 140 be shorter than the length of the tip fused portion 141 in the longitudinal direction.

[0050] From the viewpoint of blood vessel passageability due to the reduced profile, the balloon 140 preferably has a ratio of the film thickness of the straight portion 143 that is continuous with the base end of the distal tapered portion 142 to the film thickness of the distal tapered portion 142 that is 1:1.10 or more and 1:1.18 or less, and more preferably 1:1.10 or more and less than 1:1.13.

[0051] [Manufacturing Method] Next, a manufacturing method for the balloon catheter 100 according to this embodiment will be described.

[0052] As shown in FIG. 5 , the method for manufacturing the balloon catheter 100 includes the steps of: preparing a shaft portion 110 and a balloon 140 having wing portions 150 formed in a distal tapered portion 142 located at the proximal end of a fused distal portion 141 fused to the shaft portion 110 (preparation step S1); arranging the balloon 140 on the distal side of the shaft portion 110 (arrangement step S2); applying heat to the distal side of the balloon 140 to fuse the balloon 140 to the shaft portion 110 and form the fused distal portion 141 (fusion step S3); and forming, by the heat applied to the distal side of the balloon 140, a second portion 142B, which is located distal to a first portion 142A having foldable wing portions 150 formed therein during expansion / contraction of the balloon 140, and which does not have foldable wing portions 150 formed therein during expansion / contraction of the balloon 140 (tip tapered portion processing step S4).

[0053] The method for manufacturing the balloon catheter 100 may include other steps before or after each of the steps described above. The manufacturing method presents the elements of the steps in an exemplary order, and is not limited to the order of the operations shown in Figure 5. The order may be changed as appropriate, taking into account workability and other factors, as long as the processing results are consistent.

[0054] In this embodiment, a method for shaping the balloon 140 alone without joining the balloon 140 to the shaft portion 110 is disclosed. However, the balloon can also be shaped in a state where the balloon 140 is joined to the shaft portion 110.

[0055] <Preparation Step> The preparation step S1 is a step of preparing the inner tube 120 and outer tube 130 that will form the shaft portion 110, and the balloon 140 that will be fused to the shaft portion 110.

[0056] The balloon 140 prepared in the preparation step S1 is shaped to have the wing portions 150 by a shaping device. The shaping device has a mold capable of forming the wing portions 150, and clamps a portion of the balloon 140 to give it a predetermined shape.

[0057] <Placement Step> The placement step S2 is a step of placing the shaped balloon 140 at the attachment position of the shaft portion 110. At this time, the distal tip 160 may be placed on the distal side of the balloon 140. In the placement step S2, the balloon 140, the shaft portion 110, etc. may be placed inside the fusion device 300, or the balloon 140 may be placed on the shaft portion 110 in advance and then set into the fusion device.

[0058] <Fusing Step> The fusion step S3 is a step of applying heat to the tip side of the balloon 140 to fuse the balloon 140 to the shaft portion 110, thereby forming the fused tip portion 141.

[0059] 7, the fusion step S3 forms the fused tip portion 141 using a fusion device 300. The fusion device 300 includes a support member 310, an external force application member 320, and a laser irradiation unit 330.

[0060] The support member 310 is disposed so as to cover the deflated balloon 140 when it is placed on the shaft portion 110. The support member 310 is made of a material that is elastically deformable in the radial direction when subjected to an external force, in order to prevent the balloon 140 from shifting position relative to the shaft portion 110. The support member 310 supports the shaft portion 110 and the balloon 140 when a radially inward force is applied to it.

[0061] The external force application member 320 is disposed so as to cover the outer peripheral surface of the support member 310, and applies an external force to the support member 310. The external force application member 320 is made of a material harder than the support member 310, and applies a radially inward external force to the support member 310 while surrounding the support member 310. This allows the support member 310 to maintain a state in which it supports the shaft portion 110 and the balloon 140.

[0062] The laser irradiation unit 330 irradiates a laser of a predetermined wavelength onto the fused portion on the tip side of the balloon 140 supported by the support member 310, thereby forming the tip fused portion 141. The laser irradiation range by the laser irradiation unit 330 is set to at least an area where the tip fused portion 141 can be formed.

[0063] The laser emitted from the laser irradiation unit 330 is pinpointed to the fused area, resulting in a more localized heat conduction range than with conventional processing methods using shrink tubing. This allows the longitudinal length of the second portion 142B formed in the distal tapered portion 142 to be shortened. This allows the balloon catheter 100 to achieve both bendability and rewrapability in the distal tapered portion 142.

[0064] <Tip Tapered Portion Processing Step> The tip tapered portion processing step S4 is a step of forming first portion 142A to third portion 142C in tip tapered portion 142 by utilizing heat from the laser irradiated when tip fused portion 141 is formed.

[0065] In the distal end tapered portion processing step S4, heat from the laser irradiation is transmitted to a predetermined region from the distal end to the proximal end of the distal end tapered portion 142, thereby forming the second portion 142B distal to the first portion 142A. The heat from the laser irradiation melts and deforms parts of the distal end tapered portion 142 in the second portion 142B and the third portion 142C, causing the fold 153 to disappear or partially deform. In the distal end tapered portion processing step S4, the heat from the laser irradiation is not transmitted to the first portion 142A because the laser irradiation range is limited. Therefore, the fold 153 in the first portion 142A does not change from its original shape, and the shape of the first wing portion 151 is also maintained.

[0066] Since second portion 142B is the portion closest to tip fused portion 141, heat from the laser irradiation is easily transmitted thereto, and second portion 142B is formed in a state in which blade portion 150 and fold 153 have disappeared due to melting and deformation. Alternatively, if blade portion 150 is not formed in the shaping step, second portion 142B is formed as a portion without blade portion 150 regardless of the influence of heat from laser irradiation.

[0067] The third portion 142C corresponds to the portion to be shaped in the shaping step, and the fold 153 is melted and deformed by the heat from the laser irradiation, forming the second wing portion 152 as shown in FIG. 4C.

[0068] After the tip tapered portion processing step S4, the balloon catheter 100 can be manufactured by attaching the hub 180 to the shaft portion 110 and performing other processing steps as necessary.

[0069] As described above, the balloon catheter 100 according to this embodiment comprises a hollow shaft portion 110 and a deflatable balloon 140 disposed radially outward of the shaft portion 110. The balloon 140 comprises a fused tip portion 141 fixed to the shaft portion 110 and a tapered tip portion 142 located at the base end of the fused tip portion 141. The tapered tip portion 142 comprises a first portion 142A and a second portion 142B located distal to the first portion 142A. When the balloon 140 is in a deflating state, the first portion 142A comprises first wing portions 151 curved circumferentially, and the second portion 142B does not comprise wing portions 150.

[0070] Furthermore, the method for manufacturing the balloon catheter according to this embodiment includes the steps of preparing a shaft portion 110 and a balloon 140 having a folded shape at a distal tapered portion 142 located at the base end of a distal fused portion 141 that is fused to the shaft portion 110; arranging the balloon 140 on the distal side of the shaft portion 110; applying heat to the distal side of the balloon 140 so that the balloon 140 fuses to the shaft portion 110 to form the distal fused portion 141; and using the heat applied to the distal side of the balloon 140 to form a second portion 142B that is located distal to a first portion 142A that is given a folded shape that can be folded when the balloon 140 is expanded or contracted, and that does not have a folded shape that can be folded when the balloon 140 is expanded or contracted.

[0071] The balloon catheter 100 has a first section 142A that is given a folded shape and a second section 142B that is not given a folded shape formed in the distal tapered section 142. As a result, the balloon catheter 100 achieves both rewrapping ability and bendability, achieving ease of passage due to a reduced profile and high operability due to improved bendability. Therefore, in procedures that require repeated expansion and contraction operations, the balloon catheter 100 allows one device to be used multiple times without changing the device, contributing to a reduction in the number of devices used during a procedure.

[0072] This application is based on Japanese Patent Application No. 2023-164697, filed on September 27, 2023, the disclosure of which is incorporated herein by reference in its entirety.

[0073] 100 Balloon catheter, 110 Shaft, 120 Inner tube, 130 Outer tube, 140 Balloon (140a Outer outer peripheral surface, 140b Inner outer peripheral surface), 141 Distal fused portion, 142 Distal tapered portion, 142A First portion, 142B Second portion, 142C Third portion, 143 Straight portion, 144 Base end tapered portion, 145 Base end fused portion, 150 Wing portion, 151 First wing portion, 152 Second wing portion, 153 Fold, 154 Tip of first wing portion, 155 Tip of second wing portion, 160 Distal tip, 170 Contrast marker, 180 Hub, 200 Shaping device, 300 Fusion device, A1 A1: length of the first blade; A2: length of the second blade; G: guide wire.

Claims

1. A balloon catheter having a hollow shaft portion and a collapsible balloon disposed radially outward of the shaft portion, wherein the balloon has a fused tip portion fixed to the shaft portion and a tapered tip portion located at the base end of the fused tip portion, the tapered tip portion having a first section and a second section located further distal than the first section, the first section having wing portions curved in the circumferential direction when the balloon is in a deflated state, and the second section having no wing portions.

2. The balloon catheter as described in claim 1, wherein the tip tapered portion has a third portion between the first portion and the second portion, the first portion having a first wing portion as the wing portion when the balloon is in a deflated state, and the third portion having a second wing portion as the wing portion when the balloon is in a deflated state, and a wing length A2 between the fold formed in the second wing portion and the apex of the second wing portion is shorter than a wing length A1 between the fold formed in the first wing portion and the apex of the first wing portion.

3. A balloon catheter as described in claim 1 or 2, wherein the length in the longitudinal direction of the second portion is shorter than the length in the longitudinal direction of the tip fused portion.

4. A balloon catheter as described in claim 1 or 2, wherein the balloon has a straight portion continuing from the base end of the distal tapered portion, and the ratio of the film thickness of the straight portion to the film thickness of the distal tapered portion is 1:1.10 or greater and 1:1.18 or less.

5. The balloon catheter according to claim 4, wherein the ratio of the film thickness of the straight portion to the film thickness of the tip tapered portion is equal to or greater than 1:1.10 and less than 1:1.

13.

6. A method for manufacturing a balloon catheter, comprising the steps of: preparing a shaft portion and a balloon having a folded shape at a tip tapered portion located at the base end of a tip fused portion that is fused to the shaft portion; positioning the balloon at the tip side of the shaft portion; applying heat to the tip side of the balloon so that the balloon fuses to the shaft portion to form the tip fused portion; and forming a second portion that does not have the wing portion and is located further distal than a first portion having a wing portion that can be folded when the balloon is expanded or contracted, by the heat applied to the tip side of the balloon.

7. The method for manufacturing a balloon catheter as described in claim 6, wherein the tip tapered portion has a third portion between the first portion and the second portion, the first portion having a first wing portion as the wing portion when the balloon is in a deflated state, and the third portion having a second wing portion as the wing portion when the balloon is in a deflated state, and a wing length A2 between the fold formed in the second wing portion and the apex of the second wing portion is shorter than a wing length A1 between the fold formed in the first wing portion and the apex of the first wing portion.

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