JP2014200272A - Balloon catheter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a balloon catheter capable of effectively expanding an organism lumen where blockage, narrowing and fusion occur.SOLUTION: A balloon catheter 10 includes: an outer tube 20 which is tubular; an inner tube 30 which is disposed to be movable in an axial direction within the outer tube 20; and a cylindrical balloon 40 which has a first aperture end part 40A connected to a tip of the outer tube 20 and a second aperture end part 40B connected to a tip of the inner tube 30, includes at least one base end side folding part 42 that is folded toward the base end side in a form of a convex, and is capable of supplying a liquid for application of pressure through a lumen 25 formed between the outer tube 20 and the inner tube 30. As a result of application of pressure by supplying the liquid for application of pressure from the folded state and transfer of the inner tube 30 toward the tip relative to the outer tube 20, the balloon can extend the base end side folding part 42 and protrude toward the tip of the outer tube 20.

Description

  The present invention relates to a balloon catheter for insertion into an occlusion, stenosis, adhesion, or the like generated in a living body lumen.

  Conventionally, an outer tube, an inner tube that can move in the outer tube in the axial direction, and one end of the outer tube are used to treat occlusions, strictures, adhesions, and the like that have occurred in a body lumen such as an oviduct. A balloon catheter is used that includes a balloon joined to the distal end and the other end joined to the distal end of the inner tube. When such a balloon catheter is used for treatment of the fallopian tube, first, an endoscope is inserted into the lumen of the inner tube, and the distal end of the endoscope reaches the distal end of the outer tube. Next, the balloon catheter is inserted into the uterus from the cervix, with the balloon completely housed in the lumen of the outer tube. Then, after the fallopian tube opening is confirmed by an endoscope, a balloon pressurizing fluid is caused to flow into the lumen between the outer tube and the inner tube to bring the balloon into a pressurized state, and the inner tube is pushed toward the distal end side. As a result, the balloon is slid to the distal end side so as to protrude from the distal end of the outer tube while being turned over, and the balloon is inserted into the oviduct. Then, the lesioned part is expanded (treated) with a balloon while observing a lesioned part such as an obstructed part, a stenosis part, and an adhesion part with an endoscope.

  As such a slide-type balloon catheter, Patent Document 1 discloses a structure including a balloon in which a distal end portion is thinner than a proximal end portion when the balloon is expanded so as to be easily inserted into an excessively narrowed portion. Is described.

  Further, Patent Document 2 describes that a material having a high pressure expansion property and a low region are provided on the balloon by changing the material depending on the part of the balloon.

Japanese Patent Application Laid-Open No. 8-066476 JP-A-10-328306

  However, the balloon catheter that is deployed while turning the balloon upside down as described above has a rounded tip of the balloon that is deployed, so that, for example, the adhesion of the oviduct or the like cannot be sufficiently peeled off, and treatment to expand the lesion is difficult There is.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a balloon catheter that can effectively expand a biological lumen in which occlusion, stenosis, adhesion, or the like has occurred.

  A balloon catheter according to the present invention that achieves the above object includes a tubular outer tube, an inner tube that is axially movable inside the outer tube, and a first opening end portion at a distal end portion of the outer tube. And a second opening end portion is joined to the distal end portion of the inner tube, and includes at least one proximal-side folded portion that is convexly folded toward the proximal end side, and the outer tube and the inner tube A cylindrical balloon capable of supplying a pressurizing fluid from a lumen formed between the two, the balloon supplying and pressurizing the pressurizing fluid from a folded state, and the inner tube By moving in the distal direction with respect to the outer tube, it is possible to project toward the distal end side of the outer tube while expanding the proximal end side folded portion.

  The balloon catheter configured as described above can project the balloon in the distal direction while maintaining the shape of the distal end portion of the balloon with a small diameter while deploying the proximal-side folded portion, and thus, for example, occlusion, stenosis and adhesion It is possible to effectively expand a living body lumen in which, etc. occur.

  The balloon has a reinforcing portion that is formed to have a thickness, hardness, and surface roughness larger than that of an adjacent portion at a distal-end folded portion that is convex and folded toward the distal end side. For example, by advancing the reinforcing part in the distal direction, the stenosis, occlusion and adhesion of the living body lumen can be more effectively eliminated by the reinforcing part. In particular, even when a fibrous adhesion having a high adhesion force is generated, the adhesion can be peeled off by cutting off the fiber by the reinforcing portion.

  If the balloon has at least two proximal-side folded portions, the balloon can be unfolded at each proximal-side folded portion to cause the balloon to protrude longer in the distal direction. Insertability can be demonstrated.

  At least two of the proximal-side folded portions are expanded from the radially inner proximal-side folded portion by moving the inner tube in the distal direction relative to the outer tube from the folded state. For example, the balloon can be protruded stepwise from the inside, and higher peelability and penetration can be exhibited.

  At least two of the proximal-side folded portions are expanded from the radially outer proximal-side folded portion by moving the inner tube in the distal direction relative to the outer tube from the folded state. For example, the balloon can be protruded step by step so that it is turned over from the outside, and the balloon is in contact with the inner wall of the living body lumen with low friction and suppresses damage to the living tissue as much as possible. Can be pushed forward in the direction of the distal end and inserted into the living body lumen to exhibit high peelability and insertability.

It is a top view which shows the balloon catheter which concerns on embodiment. It is an expanded sectional view of the front-end | tip part of the balloon catheter of the state which accommodated the balloon in the outer tube | pipe. It is an expanded sectional view of the balloon of the state which accommodated the balloon in the outer tube | pipe. It is a top view of the balloon catheter which shows the time of moving an outer cylinder to the front end direction. It is an expanded sectional view which shows the front-end | tip part of a balloon catheter when an inner tube | pipe is moved to a front-end | tip direction and a balloon is partially expanded. It is an expanded sectional view showing the tip part of a balloon catheter when the inner tube is further moved in the tip direction and the balloon is partially expanded. It is an expanded sectional view which shows the front-end | tip part of a balloon catheter when an inner tube | pipe is further moved to a front-end | tip direction and a balloon is fully expand | deployed. It is the schematic which shows at the time of inserting a balloon into an oviduct and cutting off the fibrous adhesion of an oviduct. It is an expanded sectional view which shows the front-end | tip part of the balloon catheter when the inner tube | pipe in the modification of a balloon catheter is moved to a front-end | tip direction, and a balloon is partially expanded. It is an expanded sectional view which shows the front-end | tip part of the balloon catheter when the inner tube | pipe in the modification of a balloon catheter is moved further to a front-end | tip direction, and a balloon is partially expanded. It is an expanded sectional view which shows the front-end | tip part of the balloon catheter when the inner tube | pipe in the modification of a balloon catheter is moved further to a front-end | tip direction, and a balloon is partially expanded. It is an expanded sectional view which shows partially the balloon at the time of moving the inner pipe | tube in the front end direction in the other modification of a balloon catheter, and expand | deploying a balloon.

  Embodiments of the present invention will be described below with reference to the drawings. In addition, the dimension ratio of drawing is exaggerated on account of description, and may differ from an actual ratio.

  The balloon catheter 10 according to the present embodiment is for inserting into a closed part, a stenosis part, an adhesion part or the like generated in a living body lumen such as an oviduct and expanding the living body lumen. In this specification, the side of the balloon catheter 10 to be inserted into the living body lumen is referred to as “tip” or “tip side”, and the proximal side for operation is referred to as “base end” or “base end side”.

  First, the structure of the balloon catheter 10 will be described. As shown in FIGS. 1 to 3, the balloon catheter 10 includes a tubular outer tube 20, an inner tube 30 that can move in the outer tube 20 in the axial direction, and one end attached to the distal end of the outer tube 20. A balloon 40 whose end is attached to the tip of the inner tube 30 and an outer cylinder 50 that covers the outer side of the outer tube 20 are provided. A first lumen 35 for inserting a medical instrument such as an endoscope (oviduct mirror) or a guide wire is formed inside the inner tube 30, and a balloon is interposed between the outer tube 20 and the inner tube 30. A second lumen 25 through which a pressurizing fluid for pressurizing 40 flows is formed.

  The outer tube 20 includes an outer tube body 21 that is a long tube body, and an outer tube hub 22 that is fixed to the proximal end of the outer tube body 21. The outer tube main body 21 is a tube body having substantially the same outer diameter from the distal end to the proximal end. The outer tube body 21 preferably has an outer diameter of about 2 to 10 mm, more preferably about 2.3 to 8 mm, and an inner diameter of about 1.2 to 7.8 mm, more preferably. Is about 1.5 to 5.8 mm, and the length is preferably about 100 to 1500 mm, more preferably about 200 to 1000 mm.

  The outer tube main body 21 is made of, for example, polyolefin such as polypropylene and polyethylene, and olefin-based elastomer (for example, polyethylene elastomer and polypropylene elastomer), polyester such as polyethylene terephthalate, soft polyvinyl chloride, polyurethane and urethane-based elastomer, polyamide and amide-based elastomer. (For example, polyamide elastomer), polytetrafluoroethylene and fluororesin elastomer, polyimide, ethylene-vinyl acetate copolymer, silicone rubber, or other flexible polymer material.

  A curved portion 21 </ b> A is formed at a position that becomes a base end from a distal end of the outer tube main body 21 by a predetermined distance (specifically, 10 to 50 mm, preferably 20 to 40 mm). The degree of bending is preferably such that the angle formed by the central axis of the distal end portion of the outer tube main body 21 and the central axis of the proximal end portion of the outer tube main body 21 is about 100 to 160 °.

  The outer tube hub 22 includes a passage through which the inner tube 30 is inserted, and an injection port 22A that communicates with the second lumen 25 and injects the pressurizing fluid into the second lumen 25. The passage through which the inner tube 30 is inserted is provided with a packing (not shown) that can slide with the inner tube 30 while maintaining liquid-tightness with the inner tube 30. In the outer tube hub 22, the proximal end portion of the outer tube main body 21 is inserted and fixed to the distal end side of the outer tube hub 22.

  The outer tube hub 22 includes, for example, polycarbonate, acrylic resin (polyacrylate (for example, polymethyl methacrylate), polyetherimide, polyacrylamide, acrylonitrile-styrene copolymer, acrylonitrile-butadiene-styrene copolymer, etc.), polyester ( For example, polyethylene terephthalate, polybutylene terephthalate), polyolefin (for example, polyethylene, polypropylene, ethylene-propylene copolymer), styrene resin (polystyrene, methacrylate-styrene copolymer, methacrylate-butylene-styrene copolymer, polyvinyl chloride ( For example, hard vinyl chloride), polyamide, polysulfone, polyarylate, or other hard or semi-hard resin, stainless steel, titanium or titanium alloy It can be formed by a metal.

  The inner tube 30 includes a tubular inner tube main body 31 and an inner tube hub 32 fixed to the proximal end of the inner tube main body 31. The inner tube main body 31 can move in the outer tube main body 21 in the axial direction. The outer diameter of the inner tube main body 31 is preferably about 0.8 to 6.8 mm, more preferably about 1 to 5 mm, and the wall thickness is preferably about 0.025 to 1 mm, more preferably. Is about 0.03 to 0.5 mm, and the length is preferably about 100 to 1500 mm, more preferably about 200 to 1000 mm. The inner pipe main body 31 is made of, for example, a metal pipe such as stainless steel, titanium, or a titanium alloy, or a relatively hard material such as polyamide, PTFE (polytetrafluoroethylene), ETFE, FEP, or PFA. Preferably it is formed.

  The inner tube hub 32 has an internal passage for inserting a medical instrument such as a guide wire or an endoscope into the first lumen 35. As the material for forming the inner tube hub 32, the material described for the outer tube hub 22 can be preferably used.

  As shown in FIGS. 2 and 3, the balloon 40 is for expanding a closed portion, a stenosis portion, an adhesion portion and the like in a living body lumen, and the first opening end portion 40 </ b> A is a distal end portion of the outer tube 20. The second open end 40B is joined to the tip of the inner tube 30. The balloon 40 is folded back in the axial direction, becomes a bellows shape so as to overlap in the radial direction, and can be accommodated in the outer tube 20. The balloon 40 is accordion-shaped and accommodated in the outer tube 20, and a plurality of distal-side folded portions 41 that are convex toward the distal end side and a plurality of proximal-side folded portions that are convex toward the proximal end side Part 42. The distal end side folded portion 41 is formed with a reinforcing portion 43 that is thicker than the adjacent portion so that a step is formed on the outer surface side (side not in contact with the pressurizing fluid).

  Each of the plurality of cylindrical portions 44A to 44P folded and overlapped with the balloon 40 has a single-layer cylindrical shape, and the innermost cylindrical portion 44A is joined to the distal end portion of the inner tube 30, and the outermost cylindrical portion 44P. Is joined to the tip of the outer tube 20. The cylindrical portions 44B to 44O between the cylindrical portion 44A and the cylindrical portion 44P are formed so as to be thinner as the cylindrical portions arranged on the inner side. In addition, the length of the cylindrical portions 44B to 44O is formed shorter as the cylindrical portion disposed on the inner side. Such a balloon 40 can be formed by, for example, injection molding, but the manufacturing method is not particularly limited. The dimensions of the balloon 40 are not particularly limited, but the wall thickness is preferably about 0.01 to 0.7 mm, more preferably about 0.06 to 0.10 mm, and the balloon 40 is completely deployed ( The axial length when expanded) is preferably about 50 to 200 mm, more preferably about 60 to 100 mm. The thickness of the reinforcing portion 43 is preferably about 150 to 800%, more preferably about 200 to 400%, of the thickness of the balloon 40 in a portion adjacent to the reinforcing portion 43.

  As shown in FIG. 1, the outer cylinder 50 includes an outer cylinder main body 51 and an outer cylinder hub 52 fixed to the base end of the outer cylinder main body 51. The outer cylinder 50 partially covers the outer tube main body 21 and is movable along the axial direction of the outer tube 20. By moving the outer tube 50 along the axial direction of the outer tube 20 and storing the curved portion 21A of the outer tube 20 in the outer tube 50, the curved portion 21A can be made substantially linear. By exposing the curved portion 21A from the outer cylinder 50, the curved portion 21A can be curved. The outer cylinder main body 51 is a cylinder having substantially the same outer diameter from the distal end to the proximal end. The outer diameter of the outer cylinder main body 51 is preferably about 2.2 to 12 mm, more preferably about 2.5 to 8.2 mm, and the thickness is preferably about 0.05 to 1 mm. More preferably, it is about 0.1-0.5 mm, and it is preferable that the length is about 90-1300 mm, More preferably, it is about 190-900 mm. The outer cylinder main body 51 is preferably formed of a relatively hard material such as a fluorine-based resin such as polyamide, PTFE (polytetrafluoroethylene), ETFE, FEP, or PFA.

  The outer cylinder hub 52 functions as an operation unit when operating the outer cylinder 50. By providing such an outer cylinder hub 52, the operation of the outer cylinder 50 is facilitated. The outer cylinder hub 52 is made of polycarbonate, acrylic resin (polyacrylate (for example, polymethyl methacrylate), polyacrylamide, acrylonitrile-styrene copolymer, acrylonitrile-butadiene-styrene copolymer), polyester (for example, polyethylene terephthalate, poly Butylene terephthalate), polyolefin (eg, polyethylene, polypropylene, ethylene-propylene copolymer), styrenic resin (polystyrene, methacrylate-styrene copolymer, methacrylate-butylene-styrene copolymer, polyvinyl chloride (eg, hard vinyl chloride) , Polyamide, polyamide elastomer, polysulfone, polyarylate and other hard or semi-rigid resins, stainless steel, titanium or titanium alloys It can be formed by the genus.

  Next, a method of using the balloon catheter 10 according to the present embodiment will be described by taking as an example a case where the adhesion portion generated in the fallopian tube is peeled off to eliminate occlusion of the fallopian tube due to adhesion.

  First, with the balloon 40 folded back in a bellows shape and accommodated in the outer tube 20 (see FIGS. 2 and 3), the endoscope is inserted into the first lumen 35 from the proximal end side of the inner tube 30. The tip of the endoscope is made to reach the tip of the outer tube 20. Then, as shown in FIG. 4, the outer tube 50 is moved to the distal end side of the outer tube 20 to store the curved portion 21A of the outer tube 20 in the outer tube 50, and the balloon catheter 10 is made substantially linear, The distal end portion of the outer tube main body 21 is projected from the outer tube 50.

  Next, the balloon catheter 10 is inserted until the tip of the outer tube 20 reaches the uterus beyond the cervix. At this time, since the balloon catheter 10 is substantially straight due to the outer tube 50, the insertion operation is easy and the inner wall of the inserted lumen is not easily damaged.

  Next, the outer cylinder 50 is pulled to the proximal end side to the state shown in FIG. 1, the curved portion 21A is exposed in the uterus, and the tip of the outer tube 20 is shifted from the cervical extension line. The tube T is placed in the fallopian tube mouth T1 (see FIG. 8). At this time, since the outer tube 20 is bent at the bending portion 21A, the tip of the outer tube 20 can be easily brought close to the fallopian tube mouth T1 in the uterus. Next, a liquid for pressurization is injected into the second lumen 25 from the injection port 22A, and the inside of the second lumen 25 is brought into a pressurized state. When the inner tube 30 is pushed into the distal end side and the inner tube 30 and the balloon 40 are moved to the distal end side, as shown in FIGS. 5 to 7, the distal end side folded portion 41 and the proximal end folded portion 42 of the balloon 40. Are expanded sequentially. At this time, since the cylindrical portions 44B to 44O that are folded and overlapped with the balloon 40 are thinner and shorter toward the inner side, the cylindrical portions 44B to 44O are sequentially deployed from the inner side and moved so as to protrude toward the distal end. The portion is inserted into the fallopian tube T while maintaining the shape of the small diameter. At this time, the endoscope also moves to the distal end side in conjunction with the balloon 40. Further, a reinforcing portion 43 having a step is formed at the distal side folded portion 41 of the balloon 40, and is thicker and harder than the adjacent portion. Therefore, when the balloon 40 moves forward, the reinforcing portion 43 causes the oviduct T to move forward. Adhesion can be effectively removed. For this reason, even in the case of a fibrous adhesion having a particularly high adhesion, as shown in FIG. 8, the adhesion can be peeled off by cutting off the fibers F by the reinforcing portion 43. Further, since the balloon 40 expands the distal end side folded portion 41 and the proximal end folded portion 42 and extends toward the distal end side, the distal end side becomes a tapered shape having a smaller diameter than the proximal end side. It is easy to enter the stenosis and has high penetration. Then, by providing a plurality of reinforcing portions 43 having a high effect of peeling adhesion in the axial direction, the plurality of reinforcing portions 43 are sequentially inserted into the fallopian tube T, and higher adhesion peelability and insertion property are exhibited. .

  Thereafter, the pressure in the second lumen 25 is reduced, the tip of the endoscope is always aligned with the tip of the balloon 40, the inner tube 30 is pulled back while observing the inside of the oviduct T, and the balloon 40 is again bellows-shaped. In the outer tube 20. Then, the outer tube 50 is moved to the distal end side of the outer tube 20, the curved portion 21A of the outer tube 20 is accommodated in the outer tube 50, and the balloon catheter 10 is removed from the body in a substantially linear shape.

  As described above, the balloon catheter 10 according to the present embodiment includes the tubular outer tube 20, the inner tube 30 disposed in the outer tube 20 so as to be axially movable, and the first end portion of the outer tube 20. The opening end 40A is joined, and the second opening end 40B is joined to the distal end of the inner tube 30, and includes at least one proximal-side folded portion 42 that is convex and folded toward the proximal end. A cylindrical balloon 40 capable of supplying a pressurizing fluid from a second lumen 25 formed between the outer tube 20 and the inner tube 30, and the balloon 40 is used for pressurization from a folded state. By supplying and pressurizing the fluid and moving the inner tube 30 in the distal direction with respect to the outer tube 20, it is possible to protrude toward the distal end side of the outer tube 20 while developing the folding. For this reason, the balloon 40 can be inserted into the living body lumen while maintaining the shape of the distal end portion of the balloon 40 in a small diameter, and the living body lumen is pushed and expanded to effectively reduce the stenosis, occlusion and adhesion in the lumen. Can be resolved.

  In addition, since the balloon 40 has a reinforcing portion 43 having a thickness and hardness larger than that of the adjacent portion, the distal end side folded portion 41 which is convexly folded toward the distal end side has the reinforcing portion 43 at the distal end. By advancing in the direction, stenosis, occlusion and adhesion in the body lumen can be more effectively eliminated by the reinforcing portion 43. In particular, even when a fibrous adhesion having a high adhesion force is generated, the adhesion can be peeled off by cutting the fiber F by the reinforcing portion 43.

  In addition, since the balloon 40 has at least two proximal-side folded portions 42, the folded-back can be unfolded at each proximal-side folded portion 42 so that the balloon 40 can protrude longer in the distal direction, and higher releasability. In addition, the insertion property can be exhibited.

  Further, at least two proximal-side folded portions 42 are sequentially deployed from the radially inner proximal-side folded portion 42 by moving the inner tube 30 in the distal direction relative to the outer tube 20 from the folded state. Therefore, the balloon 40 can be protruded in a stepwise manner from the inside, and higher peelability and insertability can be exhibited.

  Note that the present invention is not limited to the above-described embodiments, and various modifications can be made by those skilled in the art within the technical idea of the present invention. For example, in the above-described embodiment, the distal end side folded portion 41 and the proximal end side folded portion 42 that are radially inward are deployed from the distal end side folded portion 61 and the outer distal end side folded portion 61 and the modified examples shown in FIGS. You may make it expand | deploy from the base end side folding | returning part 62. FIG. This can be achieved, for example, by forming the plurality of tube portions that are folded and overlapped with the balloon 60 so that the thickness is thinner toward the outer side and the outer side is easier to deploy than the inner side. Alternatively, the thickness can be realized without changing the wall thickness, by forming the length of the plurality of cylindrical portions that are folded and overlapped with the balloon so that the inner side is longer and the outer side is easier to deploy than the inner side. Thus, the order of deployment can be arbitrarily adjusted by appropriately setting at least one of the thickness of the balloon and the length of the tube portion.

  As shown in FIGS. 9 to 11, when the balloon 60 is deployed from the distal end side folded portion 61 and the proximal end folded portion 62 on the radially outer side, the balloon 60 is turned over from a portion close to the outer tube 20. Since the balloon 60 is in contact with the inner wall of the living body lumen with low friction, the damage to the living tissue is suppressed as much as possible, and the inner part of the balloon 60 that has not yet been deployed is pushed forward to enter the living body lumen. It can be inserted and the living body lumen can be expanded to eliminate stenosis, occlusion and adhesion in the lumen. At this time, the balloon 60 being deployed is supported by an inner portion of the balloon 60 that has not yet been deployed, as indicated by the white arrow shown in FIG. 10, and moves radially outward with the proximal end folded portion 62 as a fulcrum. Since the force which expands toward it is received, the effect which expands a biological lumen can be improved.

  In addition, the number of balloon folds is not particularly limited, but may be 1 to 20 proximal-side folded portions that are convexly folded toward the proximal side when the balloon is housed in the outer tube. preferable.

  Moreover, in this embodiment, although the reinforcement part 43 provided in the front end side folding | returning part 41 is formed by thickening the material of the balloon 40, you may coat | cover another material on the surface of a balloon. Although the material to coat | cover is not specifically limited, The material harder than the material of a balloon is preferable, and resin and a metal can be applied. Therefore, for example, the reinforcing portion can be configured by setting the thickness of the balloon to be uniform and setting only the hardness to be partially increased. In addition, as shown in FIG. 12, the surface roughness of the balloon 70 is roughened (increased) by the distal end side folded-back portion 71, and a large number of concavo-convex structures are formed on the surface, whereby the reinforcing portion 73 can be obtained. The surface roughness can be specified by the maximum height, ten-point average roughness, centerline average roughness, or the like shown in JIS standards. Such a reinforcing portion 73 is preferably disposed at a position facing the distal end without facing the radially outer side so that damage to the inner wall of the living body lumen can be suppressed as much as possible when the balloon 70 is deployed.

  In addition, the part to which the balloon catheter 10 according to the present embodiment can be applied is not limited to the oviduct as long as it is a lumen in a living body, and may be, for example, a blood vessel, a bile duct, a ureter, or the like.

10 balloon catheter,
20 outer tube,
21 outer pipe body,
25 Second lumen,
30 inner pipe,
35 The first lumen,
40, 60, 70 balloons,
40A first open end,
40B second open end,
41, 61, 71 distal end side folded portion,
42, 62 proximal side folded portion,
43,73 reinforcement part,
44A-44P cylinder part.

Claims (5)

A tubular outer tube,
An inner pipe disposed axially movable within the outer pipe;
A first opening end is joined to the distal end of the outer tube, and a second opening end is joined to the distal end of the inner tube, and is at least one base that is bent back into a proximal end side. A cylindrical balloon comprising an end-side folded portion and capable of supplying a pressurizing fluid from a lumen formed between the outer tube and the inner tube;
The balloon supplies and pressurizes the pressurizing fluid from the folded state, and moves the inner tube in the distal direction with respect to the outer tube, thereby expanding the outer end portion while expanding the proximal end folded portion. A balloon catheter that can project toward the distal end of a tube.   The balloon includes a reinforcing portion formed at a distal end side folded portion that is convex toward the distal end side and at least one of thickness, hardness, and surface roughness larger than that of an adjacent portion. The balloon catheter according to 1.   The balloon catheter according to claim 1, wherein the balloon has at least two proximal-side folded portions.   4. The at least two proximal end folded portions are deployed from the radially inner proximal end folded portion by moving the inner tube in the distal direction relative to the outer tube from the folded state. The balloon catheter according to 1.   4. The at least two proximal end folded portions are deployed from the radially outer proximal end folded portion by moving the inner tube in the distal direction relative to the outer tube from the folded state. The balloon catheter according to 1.

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