Balloon catheter

Abstract

A balloon catheter (1) is characterized by including: a first shaft (10) provided with a first lumen (11) and a second lumen (12); a second shaft (20) disposed at the distal end side of the first shaft (10); a balloon (30) disposed at the distal end side of the second shaft (20); and an optical fiber (40) that is disposed within the balloon (30). The balloon catheter is further characterized in that: the material constituting the first shaft (10) is a resin, and in a cross-section perpendicular to the longitudinal direction, the cross-sectional area of the resin forming the first shaft (10) is larger than the cross-sectional area of the first lumen (11) or the second lumen (12), whichever has the larger cross-sectional area; the optical fiber (40) is joined to the distal end (11d) of the first lumen (11); the proximal end (30p) of the balloon (30) is joined to the second shaft (20); and the distal end (30d) of the balloon (30) is joined to the optical fiber (40).

Description

[Technical field]

[0001] The present invention relates to a balloon catheter used, for example, for irradiating light onto tissues such as cancer cells in body lumens such as blood vessels and the digestive tract. [Background technology]

[0002] In photodynamic therapy (PDT), a photosensitizer is administered intravenously or intraperitoneally to accumulate in target tissues such as cancer cells, and then excited by irradiating the target tissue with light of a specific wavelength. When the excited photosensitizer returns to its ground state, energy conversion occurs, generating reactive oxygen species. These reactive oxygen species attack the target tissue, allowing it to be removed. In ablation (tissue cauterization) using laser light, the target tissue is cauterized by irradiating it with laser light.

[0003] Photoirradiation medical devices are used in PDT and ablation using laser light to irradiate light of a specific wavelength to the treatment site, which is the target tissue such as cancer cells in the body lumen such as blood vessels and the digestive tract. In photoirradiation medical devices, an optical fiber is placed inside the catheter tube to irradiate the target tissue with light.

[0004] Although some light irradiation medical devices are delivered to the treatment site alone, they are generally used together with a delivery catheter or endoscope. In treatment using an endoscope, the light irradiation medical device is placed inside the body from the distal side of the forceps port of the endoscope through the forceps port of the endoscope and delivered to the treatment site.

[0005] For example, Patent Document 1 describes a balloon catheter comprising a tubular substrate having a distal end and a proximal end, and a balloon member disposed at the distal end and surrounding a portion of the distal end of the tubular substrate, in which a light guide device extends from the proximal end to the distal end, and which has a light guiding device disposed within the balloon member near the distal end and fixed to the tubular substrate. The balloon catheter having the light guide device describes that the light guide device extends within the duct of the tubular substrate, and that the outer wall of the end of the tubular substrate extends within the balloon member and defines the duct, with the light guiding device being at least partially removed in advance to expose the light guiding end of the light guiding device within the balloon member, and that an optical fiber is used for the light guiding end.

[0006] Patent Document 2 describes a laser fiber guiding catheter, which is characterized in that the shaft has an inner tube and an outer tube, a balloon is placed at the tip of the outer tube, the inner tube is placed from the rear of the outer tube through the inside of the balloon to the tip of the balloon, at least a lumen into which a laser fiber can be inserted is provided inside the inner tube, an insertion port for the laser fiber is formed at the rear end of the outer tube, a photosensitive substance is fixed to the outer periphery of the balloon, a positioning marker is provided at one location on the outer periphery of the inner tube in the center of the balloon, or two markers are provided on the outer periphery of the inner tube on both sides of the balloon at equal intervals from the center of the balloon, and a laser fiber stopper is provided inside the inner tube in the center of the balloon so that the tip of the laser fiber stops at the center of the balloon. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 8-317991 [Patent Document 2] JP 2009-160446 A Summary of the Invention [Problem to be solved by the invention]

[0008] However, in the balloon catheters of Patent Documents 1 and 2, when the balloon catheter is pulled toward the hand to remove it from an endoscope, the force pulling the balloon catheter toward the hand is not easily transmitted to the distal end of the balloon, which causes a problem that it is difficult to remove the balloon catheter from the endoscope.

[0009] Furthermore, in the balloon catheters of Patent Documents 1 and 2, when the balloon catheter is placed in a curved internal lumen, the optical fiber is also bent. In addition, when the balloon catheters of Patent Documents 1 and 2 are placed in an internal lumen, the optical fiber is also bent when the balloon is constrained by the internal lumen and compressed to shorten the axial length. Therefore, there is a problem that the position of the optical fiber inside the balloon is shifted from the center of the cross section of the balloon perpendicular to the longitudinal direction, and sufficient light cannot be irradiated to the target tissue, making it impossible to perform photodynamic therapy sufficiently, or the target tissue may be irradiated with light stronger than expected, causing perforation of the internal tissue.

[0010] The present invention has been made in consideration of the above-mentioned circumstances, and its object is to provide a balloon catheter that is easily removable from an endoscope, etc., and in which the position of the optical fiber is at the center of the cross section of the balloon perpendicular to the longitudinal direction, even when the shaft is bent or the balloon is compressed. [Means for solving the problem]

[0011] The first balloon catheter that can solve the above problem comprises a first shaft having a first lumen and a second lumen, a second shaft arranged on the distal side of the first shaft, a balloon arranged on the distal side of the second shaft, and an optical fiber arranged inside the balloon, wherein the material constituting the first shaft is a resin, and in a cross section perpendicular to the longitudinal direction, the cross-sectional area of ​​the resin forming the first shaft is larger than the larger cross-sectional area of ​​either the first lumen or the second lumen, the optical fiber is joined to the distal end of the first lumen, the proximal end of the balloon is joined to the second shaft, and the distal end of the balloon is joined to the optical fiber.

[0012] The second balloon catheter that can solve the above problem comprises a first shaft having an inner cylindrical portion having a first lumen and a second lumen, a second shaft arranged on the distal side of the first shaft, a balloon arranged on the distal side of the second shaft, and an optical fiber arranged inside the balloon, and is characterized in that at least a portion of the outer surface of the inner cylindrical portion is fixed to the inner surface of the first shaft, the optical fiber is joined to the distal end of the inner cylindrical portion, the proximal end of the balloon is joined to the second shaft, and the distal end of the balloon is joined to the optical fiber.

[0013] In the balloon catheter of the present invention, the length of the second shaft in the longitudinal direction is preferably 10 times or more the minimum outer diameter of the second shaft.

[0014] In the balloon catheter of the present invention, it is preferable that, in a cross section perpendicular to the longitudinal direction at the proximal end of the second shaft, the position of the central axis of the outer shape of the second shaft differs from the position of the central axis of the outer shape of the optical fiber.

[0015] In the balloon catheter of the present invention, in a cross section perpendicular to the longitudinal direction of the second shaft, the area of ​​the gap formed between the inner surface of the second shaft and the outer surface of the optical fiber is preferably 40% or more of the area of ​​the lumen of the second shaft.

[0016] In the balloon catheter of the present invention, it is preferable that the inner surface of the second shaft has a protrusion that comes into contact with the outer surface of the optical fiber.

[0017] In the balloon catheter of the present invention, a distal tip is disposed distal to the optical fiber, and the distal end of the distal tip is preferably located distal to the distal end of the balloon. Effect of the Invention

[0018] According to the first balloon catheter of the present invention, the cross-sectional area of ​​the resin forming the first shaft in a cross section perpendicular to the longitudinal direction is larger than the cross-sectional area of ​​either the first lumen or the second lumen, and the optical fiber is joined to the distal end of the first lumen, the proximal end of the balloon is joined to the second shaft, and the distal end of the balloon is joined to the optical fiber, so that a force applied to the balloon catheter is easily transmitted to both the proximal end and the distal end of the balloon. Therefore, the ease of removal of the balloon catheter from an endoscope or the like can be improved. In addition, since the optical fiber is joined not to the proximal end of the balloon but to the distal end of the first lumen that is located proximal to the proximal end of the balloon, the optical fiber is not fixed to anything in the longitudinal direction between the distal end of the balloon and the distal end of the first lumen, and can move freely. As a result, even when the shaft of the balloon catheter is bent or the balloon is compressed, the optical fiber can be arranged in the center of the cross section of the balloon perpendicular to the longitudinal direction.

[0019] According to the second balloon catheter of the present invention, the first shaft is provided with an inner cylinder having a first lumen and a second lumen, at least a part of the outer surface of the inner cylinder is fixed to the inner surface of the first shaft, the optical fiber is joined to the distal end of the inner cylinder, the proximal end of the balloon is joined to the second shaft, and the distal end of the balloon is joined to the optical fiber. This makes it easier to transmit the force of pulling the balloon catheter to the proximal and distal ends of the balloon when removing the balloon catheter from the endoscope, etc., and makes it easier to remove the balloon catheter from the endoscope, etc. In addition, since the optical fiber is joined to the distal end of the inner cylinder, the optical fiber can move freely from the distal end of the balloon to the distal end of the first lumen in the longitudinal direction. Therefore, even when the shaft of the balloon catheter is bent or the balloon is compressed, it is possible to place the optical fiber in the center of the cross section of the balloon perpendicular to the longitudinal direction. [Brief description of the drawings]

[0020] [Figure 1] 1 is a longitudinal cross-sectional view of a first balloon catheter according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view taken along line II-II of the balloon catheter shown in FIG. 1. [Diagram 3] 2 is a longitudinal cross-sectional view of a second balloon catheter according to an embodiment of the present invention. FIG. [Figure 4] 4 is a cross-sectional view of the balloon catheter shown in FIG. 3 along line IV-IV. [Diagram 5] 13 is a cross-sectional view perpendicular to the longitudinal direction of a second shaft of a balloon catheter according to another embodiment of the present invention. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] The present invention will be described in more detail below based on the following embodiments, but the present invention is not limited to the following embodiments, and can be modified as long as it meets the purpose described above and below, and all of these modifications are included in the technical scope of the present invention. In addition, hatching and component symbols may be omitted in each drawing for convenience, but in such cases, the specification and other drawings should be referred to. In addition, the dimensions of various components in the drawings may differ from the actual dimensions because priority is given to helping understand the features of the present invention.

[0022] First, the first balloon catheter of the present invention will be described.

[0023] Fig. 1 is a longitudinal cross-sectional view of a first balloon catheter 1 according to an embodiment of the present invention, and Fig. 2 is a II-II cross-sectional view perpendicular to the longitudinal direction of the balloon catheter 1 shown in Fig. 1. As shown in Fig. 1, the balloon catheter 1 of the present invention has a first shaft 10 having a first lumen 11 and a second lumen 12, a second shaft 20 disposed on the distal side of the first shaft 10, a balloon 30 disposed on the distal side of the second shaft 20, and an optical fiber 40 disposed inside the balloon 30, the optical fiber 40 being joined to a distal end 11d of the first lumen 11, a proximal end 30p of the balloon 30 being joined to the second shaft 20, and a distal end 30d of the balloon 30 being joined to the optical fiber 40. 2, in a cross section perpendicular to the longitudinal direction, the cross-sectional area of ​​the resin forming the first shaft 10 is larger than either the larger cross-sectional area of ​​the first lumen 11 or the second lumen 12. In other words, the cross-sectional area of ​​the resin forming the first shaft 10 is larger than the larger cross-sectional area of ​​the first lumen 11 or the second lumen 12. In other words, the cross-sectional area of ​​the resin forming the first shaft 10 is larger than both the cross-sectional areas of the first lumen 11 and the second lumen 12.

[0024] In a cross section perpendicular to the longitudinal direction, the cross-sectional area of ​​the resin forming the first shaft 10 is larger than the cross-sectional area of ​​either the first lumen 11 or the second lumen 12, and the optical fiber 40 is joined to the distal end 11d of the first lumen 11, the proximal end 30p of the balloon 30 is joined to the second shaft 20, and the distal end 30d of the balloon 30 is joined to the optical fiber 40. This structure connects the proximal end 30p of the balloon 30 to the first shaft 10 via the second shaft 20, and the distal end 30d of the balloon 30 to the first shaft 10 via the optical fiber 40, so that the force pulling the first shaft 10 is easily transmitted to both the proximal end 30p and the distal end 30d of the balloon 30. This makes it possible to improve the ease of removal when removing the balloon catheter 1 from an endoscope or the like.

[0025] The optical fiber 40 is joined to the distal end 11d of the first lumen 11, the proximal end 30p of the balloon 30 is joined to the second shaft 20, and the distal end 30d of the balloon 30 is joined to the optical fiber 40, so that the optical fiber 40 is joined to the distal end 11d of the first lumen 11, which is located proximal to the proximal end 30p of the balloon 30. Therefore, in the longitudinal direction of the balloon catheter 1, the optical fiber 40 is not fixed to any other object between the distal end 30d of the balloon 30 and the distal end 11d of the first lumen 11, and the optical fiber 40 can be freely changed in position or bent in accordance with the bending state of the balloon catheter 1. As a result, when photodynamic therapy is performed by irradiating light to a target tissue, the optical fiber 40 can be positioned at the center of the cross section of the balloon 30 perpendicular to the longitudinal direction, making it easier to perform photodynamic therapy.

[0026] The proximal end 30p of the balloon 30 is preferably joined to the distal end 20d of the second shaft 20, and the distal end 30d of the balloon 30 is preferably joined to the distal end 40d of the optical fiber 40.

[0027] The optical fiber 40 and the first lumen 11, the balloon 30 and the second shaft 20, and the balloon 30 and the optical fiber 40 may be joined directly to each other or via other members. The optical fiber 40 and the first lumen 11, the balloon 30 and the second shaft 20, and the balloon 30 and the optical fiber 40 may be joined by, for example, welding, adhesion, or the like.

[0028] In the present invention, the proximal side refers to the side of the user, i.e., the hand side of the surgeon, in the longitudinal direction of the first shaft 10, and the distal side refers to the opposite side of the proximal side, i.e., the side to be treated. The direction from the proximal side to the distal side of the first shaft 10, or the direction from the distal side to the proximal side, is referred to as the longitudinal direction. The longitudinal direction can be rephrased as the distal / proximal direction of the first shaft 10.

[0029] 1, the first shaft 10 extends in the longitudinal direction and has a tubular structure including a first lumen 11 and a second lumen 12. The first lumen 11 has a distal end 11d joined to an optical fiber 40, and the optical fiber 40 can be disposed inside the first lumen 11. The second lumen 12 communicates with the inner cavity of the balloon 30 and can serve as a path for supplying a fluid to the inside of the balloon 30.

[0030] As shown in FIG. 1, the joint between the distal end 11d of the first lumen 11 and the optical fiber 40 preferably does not have a gap that communicates the first lumen 11 with the outside of the first lumen 11. In other words, the optical fiber 40 is preferably joined so as to seal the distal end 11d of the first lumen 11. Since the joint between the distal end 11d of the first lumen 11 and the optical fiber 40 does not have a gap that communicates the first lumen 11 with the outside of the first lumen 11, the fluid supplied through the second lumen 12 is prevented from entering the first lumen 11. As a result, the balloon 30 can be expanded quickly, and the time required for expanding the balloon 30 can be shortened, thereby shortening the procedure time.

[0031] The first shaft 10 is required to have at least the first lumen 11 and the second lumen 12, and may further have a lumen different from the first lumen 11 and the second lumen 12.

[0032] It is preferable that the first shaft 10 has flexibility. When the first shaft 10 has flexibility, the first shaft 10 becomes soft and easy to bend. This makes it easier to insert the balloon catheter 1 into the body.

[0033] The material constituting the first shaft 10 is a resin, and as shown in FIG. 2, in a cross section perpendicular to the longitudinal direction, the cross-sectional area of ​​the resin forming the first shaft 10 is larger than either one of the larger cross-sectional areas of the first lumen 11 and the second lumen 12. Specifically, for example, in the balloon catheter 1 shown in FIG. 2, the cross-sectional area of ​​the second lumen 12 is larger than the cross-sectional area of ​​the first lumen 11, so the cross-sectional area of ​​the second lumen 12 is compared with the cross-sectional area of ​​the resin forming the first shaft 10. In addition, when the cross-sectional area of ​​the first lumen 11 and the cross-sectional area of ​​the second lumen 12 are the same, either one of the cross-sectional areas of the first lumen 11 and the second lumen 12 may be used for comparison with the cross-sectional area of ​​the resin forming the first shaft 10. Since the cross-sectional area of ​​the resin forming the first shaft 10 is larger than either one of the larger cross-sectional areas of the first lumen 11 and the second lumen 12, the rigidity of the first shaft 10 can be increased. As a result, when a force pushing the balloon catheter 1 when inserting the balloon catheter 1 or a force pulling the balloon catheter 1 when removing the balloon catheter 1 is applied to the first shaft 10, this force is easily transmitted through the first shaft 10 to the distal end 30d and the proximal end 30p of the balloon 30, improving the ease of removal of the balloon catheter 1.

[0034] In a cross section perpendicular to the longitudinal direction, the cross-sectional area of ​​the resin forming the first shaft 10 is preferably 1.1 times or more, more preferably 1.2 times or more, and even more preferably 1.3 times or more, of the larger cross-sectional area of ​​either the first lumen 11 or the second lumen 12. By setting the lower limit of the ratio of the cross-sectional area of ​​the resin forming the first shaft 10 to the larger cross-sectional area of ​​either the first lumen 11 or the second lumen 12 within the above range, it is possible to sufficiently increase the rigidity of the first shaft 10. In addition, the cross-sectional area of ​​the resin forming the first shaft 10 is preferably 5 times or less, more preferably 4 times or less, and even more preferably 3 times or less, of the larger cross-sectional area of ​​either the first lumen 11 or the second lumen 12. By setting the upper limit value of the ratio between the cross-sectional area of ​​the resin forming the first shaft 10 and the larger cross-sectional area of ​​the first lumen 11 or the second lumen 12 within the above range, the width of the first lumen 11 and the second lumen 12 possessed by the first shaft 10 can be ensured, and the insertion of the optical fiber 40 into the first lumen 11 and the supply and removal of the fluid for expanding the balloon 30 to the second lumen 12 can be smoothly performed.

[0035] Examples of the material constituting the first shaft 10 include synthetic resins such as polyolefin resins such as polyethylene and polypropylene, polyamide resins such as nylon, polyester resins such as PET, aromatic polyetherketone resins such as PEEK, vinyl chloride resins, polyetherpolyamide resins, polyurethane resins, polyimide resins, and fluororesins such as PTFE, PFA, and ETFE. These may be used alone or in combination of two or more. Among them, the material constituting the first shaft 10 preferably contains a polyolefin resin, a polyamide resin, or a fluororesin. Since the material constituting the first shaft 10 contains a polyolefin resin, a polyamide resin, or a fluororesin, the first shaft 10 has flexibility and the surface of the first shaft 10 has improved slipperiness, so that the balloon catheter 1 has good insertability.

[0036] As shown in FIG. 1, the second shaft 20 extends in the longitudinal direction and has a tubular structure having an inner cavity. The second shaft 20 is disposed on the distal side of the first shaft 10. In other words, the second shaft 20 is disposed on the distal side of the distal end 10d of the first shaft 10. An optical fiber 40 is disposed in the inner cavity of the second shaft 20. It is preferable that the second shaft 20 is flexible. Since the second shaft 20 is flexible, the second shaft 20 becomes soft, and it becomes possible to improve the insertability of the balloon catheter 1.

[0037] The second shaft 20 may be composed of a plurality of members, but is preferably composed of a single tubular member. By comprising a single tubular member, the second shaft 20 becomes flexible. As a result, when the balloon catheter 1 is inserted into a curved body lumen, the second shaft 20 becomes easier to bend, and the insertability of the balloon catheter 1 can be improved.

[0038] Examples of the material constituting the second shaft 20 include synthetic resins such as polyolefin resins such as polyethylene and polypropylene, polyamide resins such as nylon, polyester resins such as PET, aromatic polyetherketone resins such as PEEK, vinyl chloride resins, polyether polyamide resins, polyurethane resins, polyimide resins, fluororesins such as PTFE, PFA, and ETFE, and metals such as stainless steel, carbon steel, and nickel-titanium alloy. These may be used alone or in combination of two or more. Among them, it is preferable that the material constituting the second shaft 20 contains the same material as the material constituting the first shaft 10. By containing the same material as the material constituting the first shaft 10, the physical properties such as hardness and surface slipperiness of the first shaft 10 and the second shaft 20 are close to each other, and the balloon catheter 1 can be easily inserted into the body. In addition, when the first shaft 10 and the second shaft 20 are directly joined, it is possible to increase the joining strength between the first shaft 10 and the second shaft 20.

[0039] The balloon 30 is disposed on the distal side of the second shaft 20. In other words, the balloon 30 is disposed distal to the distal end 20d of the second shaft 20. In addition, the proximal end 30p of the balloon 30 is joined to the second shaft 20, and the distal end 30d of the balloon 30 is joined to the optical fiber 40. It is preferable that the proximal end 30p of the balloon 30 is joined to the distal end 20d of the second shaft 20.

[0040] The balloon 30 is configured such that a fluid is supplied from a fluid supplier to the inside of the balloon 30 through the first shaft 10 and the second shaft 20. The balloon 30 can be expanded by supplying a fluid to the inside of the balloon 30. The balloon 30 can be deflated by removing the fluid from the inside of the balloon 30. By expanding the balloon 30, the outer surface of the balloon 30 comes into contact with the wall of a lumen in the body, such as a blood vessel or the digestive tract, and therefore the balloon 30 can be fixed inside the body. The fluid supplied to the inside of the balloon 30 may be a pressurized fluid pressurized by a pump or the like.

[0041] The type of fluid supplied into the balloon 30 may be, for example, a liquid such as physiological saline, a contrast agent, or a mixture thereof, or a gas such as air, nitrogen, or carbon dioxide. Of these, it is preferable that the fluid supplied into the balloon 30 is a gas. By supplying the fluid into the balloon 30 as a gas, the fluid present in the balloon 30 is less likely to interfere with the emitted light of the optical fiber 40 disposed inside the balloon 30 during photodynamic therapy.

[0042] 1, the balloon 30 preferably has a straight tube portion 31. By having the balloon 30 have the straight tube portion 31, it is possible to increase the contact area between the balloon 30 and the lumen wall in the body. Therefore, it is possible to fix the balloon 30 to the lumen in the body, and it becomes easier to perform photodynamic therapy.

[0043] The balloon 30 has a proximal taper portion connected to the straight tube portion 31 proximal to the proximal end 31p of the straight tube portion 31, and a distal taper portion connected to the straight tube portion 31 distal to the distal end 31d of the straight tube portion 31, and it is more preferable that the proximal taper portion and the distal taper portion are formed so as to decrease in diameter as they move away from the straight tube portion 31. By having the proximal taper portion and the distal taper portion formed so as to decrease in diameter as they move away from the straight tube portion 31, the strength of the balloon 30 can be increased, and the balloon 30 can be made less likely to break when a force is applied to the balloon 30. In addition, since the step generated when the balloon 30 is wound around the shaft can be reduced, the balloon 30 can be easily inserted into a lumen in the body. The balloon 30 can be configured so that the distal taper portion expands from the proximal taper portion through the straight tube portion 31 when a fluid is supplied. In the present invention, the expandable portion is considered to be the balloon 30.

[0044] Examples of the material constituting the balloon 30 include polyolefin resins such as polyethylene, polypropylene, and ethylene-propylene copolymer, polyester resins such as polyethylene terephthalate and polyester elastomer, polyurethane resins such as polyurethane and polyurethane elastomer, polyphenylene sulfide resins, polyamide resins such as polyamide and polyamide elastomer, vinyl chloride resins, fluorine resins, silicone resins, and natural rubbers such as latex rubber. These may be used alone or in combination of two or more. Among them, the material constituting the balloon 30 is preferably a polyamide resin, a polyester resin, or a polyurethane resin. By using a polyamide resin, a polyester resin, or a polyurethane resin as the material constituting the balloon 30, the balloon 30 can be thinned and its flexibility can be improved.

[0045] As shown in FIG. 1, the optical fiber 40 extends in the longitudinal direction. The optical fiber 40 is disposed inside the balloon 30 and joined to the distal end 11d of the first lumen 11. The optical fiber 40 is a transmission line for transmitting an optical signal to a target tissue. Although not shown, the optical fiber 40 is connected to a light source such as a semiconductor laser by a connector or the like provided at the proximal end. The optical fiber 40 has a core and a clad that covers the radial outside of the core. The material constituting the core and the clad can be, for example, a synthetic resin such as a fluorine-based resin or an acrylic resin, or a glass such as quartz glass or fluoride glass.

[0046] The optical fiber 40 preferably has a cladding-free portion in a part of the distal portion of the core. The cladding-free portion refers to a portion in which no cladding is present in at least a part of the circumferential direction of the core, and serves as the light-emitting area of ​​the optical fiber 40. Since the optical fiber 40 has a cladding-free portion, it is possible to configure a balloon catheter 1 that is of a side-illuminating type and is used in photodynamic therapy.

[0047] The position in the longitudinal direction where the non-existent cladding portion is provided is not particularly limited as long as it is a part of the distal portion of the core, but it is preferably provided in a portion including the distal end of the core. By providing the non-existent cladding portion in a portion including the distal end of the core, the non-existent cladding portion is easily formed.

[0048] The cladding-free portion can be formed, for example, by removing the cladding by etching, polishing, etc. More preferably, the outer surface of the cladding-free portion is roughened by a method such as sanding. By roughening the outer surface of the cladding-free portion, the light diffusion properties can be improved.

[0049] Examples of methods for joining the optical fiber 40 to the first lumen 11 include fusion and adhesion with an adhesive. Although not shown, the optical fiber 40 may further have a coating material. When the optical fiber 40 has a coating material, from the viewpoint of bonding with the first lumen 11, the material constituting the coating material is preferably a synthetic resin such as a polyolefin resin such as polyethylene or polypropylene, a polyamide resin such as nylon, a polyester resin such as PET, an aromatic polyether ketone resin such as PEEK, a vinyl chloride resin, a polyether polyamide resin, a polyurethane resin, a polyimide resin, or a fluororesin such as PTFE, PFA, or ETFE.

[0050] The balloon catheter 1 has the optical fiber 40, and the optical fiber 40 is disposed inside the balloon 30, so that the light emitted from the optical fiber 40 is easily directed toward the straight tube portion 31 of the balloon 30. Therefore, it becomes easier to irradiate the light used in the photodynamic therapy to the target tissue through the optical fiber 40, and the photodynamic therapy can be performed efficiently.

[0051] As shown in FIG. 1, the distal end 40d of the optical fiber 40 is preferably located distal to the distal end 30d of the balloon 30. Since the distal end 40d of the optical fiber 40 is located distal to the distal end 30d of the balloon 30, the rigidity of the distal end of the balloon catheter 1 is increased. Therefore, the balloon catheter 1 can be easily inserted into the body. Furthermore, since the distal end 40d of the optical fiber 40 is located distal to the distal end 30d of the balloon 30, the optical fiber 40 is present over the entire length of the balloon 30 in the longitudinal direction. As a result, the optical fiber 40 can be present over the entire straight tube portion 31 of the balloon 30 in the longitudinal direction, making it easier to perform photodynamic therapy.

[0052] The light amount at the tip of the optical fiber 40 is weakened, and the light amount may not be sufficient for performing photodynamic therapy. In order to supply a sufficient amount of light to the balloon 30, the distal end 40d of the optical fiber 40 is preferably located distal to the straight tube portion 31 of the balloon 30 or distal to the distal tapered portion of the balloon 30. By having the distal end 40d of the optical fiber 40 located distal to the straight tube portion 31 of the balloon 30 or distal to the distal tapered portion, a sufficient amount of light can be ensured for photodynamic therapy. In addition, when it is desired to supply light from the optical fiber 40 to the straight tube portion 31 of the balloon 30 and not to supply light to the tapered portion of the balloon 30, it is possible to irradiate light to a desired site by appropriately arranging a covering material on the optical fiber 40.

[0053] The distal end 40d of the optical fiber 40 is preferably located distal to the distal tapered portion of the balloon 30. By having the distal end 40d of the optical fiber 40 located distal to the distal tapered portion of the balloon 30, a sufficient amount of light can be ensured in photodynamic therapy. In addition, by having the distal end 40d of the optical fiber 40 located distal to the distal end 30d of the balloon 30, the rigidity of the distal end portion of the balloon catheter 1 is increased. This makes it easier to insert the balloon catheter 1 into the body.

[0054] Although not shown, the balloon catheter 1 preferably has a handle portion on the proximal side. The handle portion preferably has a longitudinally extending lumen that communicates with the first lumen 11. The lumen of the handle portion that communicates with the first lumen 11 can be used as a passage for inserting the optical fiber 40 or the like. The handle portion preferably has a lumen that includes a fluid injection portion and communicates with the second lumen 12. The lumen of the handle portion that communicates with the second lumen 12 can be used as a path for supplying and removing a fluid for expanding the balloon 30.

[0055] The proximal end 20p of the second shaft 20 is preferably joined to the distal end 10d of the first shaft 10. In other words, it is preferable that the first shaft 10 and the second shaft 20 are directly joined. By joining the proximal end 20p of the second shaft 20 to the distal end 10d of the first shaft 10, it becomes easier to join the second shaft 20 to the first shaft 10. As a result, the efficiency of manufacturing the balloon catheter 1 can be improved.

[0056] Next, a second balloon catheter of the present invention will be described. In the description of the second balloon catheter, the description of the same parts as those described above will be omitted.

[0057] Fig. 3 is a longitudinal cross-sectional view of a second balloon catheter 1 in one embodiment of the present invention, and Fig. 4 is a IV-IV cross-sectional view perpendicular to the longitudinal direction of the balloon catheter 1 shown in Fig. 3. As shown in Fig. 3 and Fig. 4, a first shaft 10 of the balloon catheter 1 includes an inner cylindrical portion 50 having a first lumen 11 and a second lumen 12, and at least a portion of the outer surface of the inner cylindrical portion 50 is fixed to the inner surface of the first shaft 10.

[0058] The first shaft 10 includes an inner cylindrical portion 50 having a first lumen 11 and a second lumen 12, at least a part of the outer surface of the inner cylindrical portion 50 is fixed to the inner surface of the first shaft 10, the optical fiber 40 is joined to the distal end 50d of the inner cylindrical portion 50, the proximal end 30p of the balloon 30 is joined to the second shaft 20, and the distal end 30d of the balloon 30 is joined to the optical fiber 40, so that the proximal end 30p of the balloon 30 is connected to the first shaft 10 via the second shaft 20, and the distal end 30d of the balloon 30 is connected to the first shaft 10 via the optical fiber 40. Therefore, when the balloon catheter 1 is removed from an endoscope or the like, the force pulling the first shaft 10 toward the hand side is easily transmitted to both the distal end 30d and the proximal end 30p of the balloon 30, and the ease of removal of the balloon catheter 1 can be improved. The proximal end 30p of the balloon 30 is preferably joined to the distal end 20d of the second shaft 20, and the distal end 30d of the balloon 30 is preferably joined to the distal end 40d of the optical fiber 40.

[0059] In addition, since the optical fiber 40 is joined to the distal end 50d of the inner cylinder portion 50, the proximal end 30p of the balloon 30 is joined to the second shaft 20, and the distal end 30d of the balloon 30 is joined to the optical fiber 40, the optical fiber 40 is not fixed to any other object between the distal end 30d of the balloon 30 and the distal end 11d of the first lumen 11 in the longitudinal direction of the balloon catheter 1, and the optical fiber 40 can freely change position and bend according to the bending state of the balloon catheter 1. Therefore, when performing photodynamic therapy in which light is irradiated to the target tissue, the optical fiber 40 can be disposed in the center of the cross section of the balloon 30 perpendicular to the longitudinal direction, making it easier to perform photodynamic therapy.

[0060] 3, the inner cylindrical portion 50 extends in the longitudinal direction. The inner cylindrical portion 50 has an inner cavity through which the optical fiber 40 is inserted.

[0061] Methods for fixing at least a portion of the outer surface of the inner cylindrical portion 50 to the inner surface of the first shaft 10 include, for example, welding, adhesion, and fixing via other components.

[0062] As shown in FIG. 1 and FIG. 3, the length L1 of the second shaft 20 in the longitudinal direction is preferably 10 times or more the minimum outer diameter of the second shaft 20. The length L1 of the second shaft 20 in the longitudinal direction indicates the longitudinal distance between the distal end 20d of the second shaft 20 and the proximal end 20p of the second shaft 20. Since the length L1 of the second shaft 20 is 10 times or more the minimum outer diameter of the second shaft 20, the length L1 of the second shaft 20 can be made sufficient, and the distance from the distal end 30d of the balloon 30 joined to the optical fiber 40 to the distal end 11d of the first lumen 11 joined to the optical fiber 40 can be increased. In other words, the distance between the two points where the optical fiber 40 is joined to another object can be increased, and the optical fiber 40 can be freely repositioned or bent in accordance with the bending state of the balloon catheter 1 in the part where the optical fiber 40 is not joined to another object. As a result, the optical fiber 40 is located at the center of the cross section of the balloon 30 perpendicular to the longitudinal direction, making it possible to efficiently perform photodynamic therapy.

[0063] The length L1 of the second shaft 20 in the longitudinal direction is preferably 10 times or more the minimum outer diameter of the second shaft 20, more preferably 11 times or more the minimum outer diameter of the second shaft 20, and even more preferably 12 times or more the minimum outer diameter of the second shaft 20. By setting the lower limit of the ratio between the length L1 of the second shaft 20 and the minimum outer diameter of the second shaft 20 within the above range, the distance from the distal end 30d of the balloon 30 joined to the optical fiber 40 to the distal end 11d of the first lumen 11 joined to the optical fiber 40 can be sufficiently increased. In addition, the upper limit of the ratio between the length L1 of the second shaft 20 and the minimum outer diameter of the second shaft 20 can be, for example, 600 times or less, 400 times or less, or 200 times or less.

[0064] As shown in FIG. 4, in a cross section perpendicular to the longitudinal direction at the proximal end 20p of the second shaft 20, the position of the central axis C20 of the outer shape of the second shaft 20 and the position of the central axis C40 of the outer shape of the optical fiber 40 are preferably different. Since the position of the central axis C20 of the outer shape of the second shaft 20 and the position of the central axis C40 of the outer shape of the optical fiber 40 are different, the optical fiber 40 can easily change position or bend freely in the respective inner cavities of the second shaft 20 and the balloon 30. Therefore, when the balloon catheter 1 is inserted into a curved body lumen, the optical fiber 40 can easily move according to the bending state of the balloon catheter 1, and the optical fiber 40 can easily be located in the center of the cross section of the balloon 30 perpendicular to the longitudinal direction. As a result, photodynamic therapy can be easily performed.

[0065] 4, in a cross section perpendicular to the longitudinal direction of the second shaft 20, the cross-sectional area of ​​the gap portion formed by the inner surface of the second shaft 20 and the outer surface of the optical fiber 40 is preferably 40% or more of the cross-sectional area of ​​the lumen of the second shaft 20. Since the cross-sectional area of ​​the gap portion formed by the inner surface of the second shaft 20 and the outer surface of the optical fiber 40 is 40% or more of the cross-sectional area of ​​the lumen of the second shaft 20, the optical fiber 40 can move freely within the second shaft 20. Therefore, even when the second shaft 20 is bent, the optical fiber 40 is likely to be located at the center of the cross section of the balloon 30 perpendicular to the longitudinal direction, making it easier to perform photodynamic therapy.

[0066] In a cross section perpendicular to the longitudinal direction of the second shaft 20, the cross-sectional area of ​​the gap portion formed by the inner surface of the second shaft 20 and the outer surface of the optical fiber 40 is preferably 40% or more, more preferably 45% or more, and even more preferably 50% or more of the cross-sectional area of ​​the lumen of the second shaft 20. By setting the lower limit of the ratio of the cross-sectional area of ​​the gap portion formed by the inner surface of the second shaft 20 and the outer surface of the optical fiber 40 to the cross-sectional area of ​​the lumen of the second shaft 20 within the above range, the optical fiber 40 can move freely in the lumen of the second shaft 20. In addition, the upper limit of the ratio of the cross-sectional area of ​​the gap portion formed by the inner surface of the second shaft 20 and the outer surface of the optical fiber 40 to the cross-sectional area of ​​the lumen of the second shaft 20 can be, for example, 99% or less, 97% or less, or 95% or less.

[0067] Fig. 5 is a cross-sectional view perpendicular to the longitudinal direction of the second shaft 20 of the balloon catheter 1 in another embodiment of the present invention. As shown in Fig. 5, it is preferable that the inner surface of the second shaft 20 has a protrusion 70 that comes into contact with the outer surface of the optical fiber 40. By having the protrusion 70 on the inner surface of the second shaft 20, it becomes possible for the protrusion 70 to determine the position of the optical fiber 40 within the second shaft 20. As a result, it is possible to restrict the position of the optical fiber 40 so that it does not deviate significantly from the central axis of the balloon 30. Note that the protrusion 70 is not joined to the optical fiber 40.

[0068] The protrusion 70 is preferably disposed on the inner surface of the distal end of the second shaft 20. By disposing the protrusion 70, which comes into contact with the outer surface of the optical fiber 40, on the inner surface of the distal end of the second shaft 20 so that the optical fiber 40 is located at the center of a cross section perpendicular to the longitudinal direction of the second shaft 20, the optical fiber 40 is likely to be located at the center of the second shaft 20 at the distal end of the second shaft 20. As a result, the optical fiber 40 is likely to be located at the center of the balloon 30, which is disposed on the distal side of the second shaft 20, even in the lumen of the balloon 30 joined to the second shaft 20, and the balloon catheter 1 can be made easy to perform photodynamic therapy.

[0069] It is preferable that a plurality of protrusions 70 are arranged on the inner surface of the second shaft 20. By providing a plurality of protrusions 70, the position of the optical fiber 40 within the second shaft 20 can be easily regulated by the protrusions 70.

[0070] 1 and 3, the tip 60 is disposed on the distal side of the optical fiber 40, and the distal end 60d of the tip 60 is preferably located distal to the distal end 30d of the balloon 30. By having the distal end 60d of the tip 60 located distal to the distal end 30d of the balloon 30, the rigidity of the distal end of the balloon catheter 1 is increased. As a result, the insertability of the balloon catheter 1 can be improved.

[0071] When the tip 60 is provided on the distal side of the optical fiber 40, the color of the tip 60 is preferably different from the color of the optical fiber 40. The color of the tip 60 is different from the color of the optical fiber 40 means that at least one of the hue, brightness, and saturation defined by JIS Z8721 is different. The color of the tip 60 is different from the color of the optical fiber 40, so that the tip 60 can be easily visually recognized under an endoscope. As a result, the position of the tip 60 and the balloon 30 in the body lumen can be easily confirmed.

[0072] As described above, the balloon catheter of the present invention comprises a first shaft having a first lumen and a second lumen, a second shaft arranged distal to the first shaft, a balloon arranged distal to the second shaft, and an optical fiber arranged inside the balloon, wherein the material constituting the first shaft is resin, and in a cross section perpendicular to the longitudinal direction, the cross-sectional area of ​​the resin forming the first shaft is larger than the larger cross-sectional area of ​​the first lumen or the second lumen, the optical fiber is joined to the distal end of the first lumen, the proximal end of the balloon is joined to the second shaft, and the distal end of the balloon is joined to the optical fiber. In a cross section perpendicular to the longitudinal direction, the cross-sectional area of ​​the resin forming the first shaft is larger than the cross-sectional area of ​​either the first lumen or the second lumen, and the optical fiber is joined to the distal end of the first lumen, the proximal end of the balloon is joined to the second shaft, and the distal end of the balloon is joined to the optical fiber, so that the force applied to the balloon catheter is easily transmitted to both the proximal end and the distal end of the balloon. Therefore, the ease of removal of the balloon catheter from an endoscope or the like can be improved. In addition, since the optical fiber is joined not to the proximal end of the balloon but to the distal end of the first lumen that is located proximal to the proximal end of the balloon, the optical fiber is not fixed to anything in the longitudinal direction between the distal end of the balloon and the distal end of the first lumen, and can move freely. As a result, when performing photodynamic therapy by irradiating light to a target tissue, even if the shaft of the balloon catheter is bent or the balloon is compressed, the optical fiber can be arranged in the center of the cross section of the balloon perpendicular to the longitudinal direction, making it easier to perform photodynamic therapy.

[0073] The second balloon catheter of the present invention has a first shaft including an inner cylindrical portion having a first lumen and a second lumen, a second shaft disposed on the distal side of the first shaft, a balloon disposed on the distal side of the second shaft, and an optical fiber disposed inside the balloon, and at least a part of the outer surface of the inner cylindrical portion is fixed to the inner surface of the first shaft, the optical fiber is joined to the distal end of the inner cylindrical portion, the proximal end of the balloon is joined to the second shaft, and the distal end of the balloon is joined to the optical fiber. Since the first shaft has an inner cylindrical portion having a first lumen and a second lumen, at least a part of the outer surface of the inner cylindrical portion is fixed to the inner surface of the first shaft, the optical fiber is joined to the distal end of the inner cylindrical portion, the proximal end of the balloon is joined to the second shaft, and the distal end of the balloon is joined to the optical fiber, when the balloon catheter is removed from an endoscope or the like, the force pulling the balloon catheter is easily transmitted to the proximal and distal ends of the balloon, making it easier to remove the balloon catheter from an endoscope or the like. In addition, by joining the optical fiber to the distal end of the first lumen, the optical fiber can move freely in the longitudinal direction from the distal end of the balloon to the distal end of the first lumen, so that even if the shaft of the balloon catheter is bent or the balloon is compressed, the optical fiber can be disposed in the center of the cross section of the balloon perpendicular to the longitudinal direction.

[0074] This application claims the benefit of priority based on Japanese Patent Application No. 2020-039082, filed on March 6, 2020. The entire contents of the specification of Japanese Patent Application No. 2020-039082, filed on March 6, 2020, are incorporated by reference into this application. [Explanation of symbols]

[0075] 1: Balloon catheter 10: First shaft 10d: Distal end of first shaft 11: 1st lumen 11d: Distal end of first lumen 11p: proximal end of first lumen 12: 2nd lumen 20: 2nd shaft 20d: Distal end of second shaft 20p: Proximal end of second shaft 30: Balloon 30d: Distal end of balloon 30p: Proximal end of balloon 31: Straight pipe section 31d: Distal end of straight pipe section 31p: Proximal end of straight tube 40: Optical fiber 40d: Distal end of optical fiber 50: Inner cylinder 50d: Distal end of inner barrel 60: Tip 60d: Distal end of tip 70: Protrusion L1: Length of the second shaft C20: Central axis of the outer shape of the second shaft C40: Central axis of the optical fiber

Claims

1. A balloon catheter for irradiating light to tissue inside a body, comprising: a first shaft having a first lumen and a second lumen; a second shaft disposed distally of the first shaft; a balloon disposed distally of the second shaft; an optical fiber disposed inside the balloon, The material constituting the first shaft is a resin, In a cross section perpendicular to the longitudinal direction, a cross-sectional area of ​​the resin forming the first shaft is larger than either one of the cross-sectional areas of the first lumen and the second lumen, the optical fiber is joined to a distal end of the first lumen; a proximal end of the balloon is attached to the second shaft; A balloon catheter, characterized in that a distal end of the balloon is joined to the optical fiber.

2. A balloon catheter for irradiating light to tissue inside a body, comprising: A first shaft including an inner cylindrical portion having a first lumen and a second lumen; a second shaft disposed distally of the first shaft; a balloon disposed distally of the second shaft; an optical fiber disposed inside the balloon, At least a portion of an outer surface of the inner cylindrical portion is fixed to an inner surface of the first shaft, the optical fiber is joined to a distal end of the inner barrel; a proximal end of the balloon is attached to the second shaft; A balloon catheter, characterized in that a distal end of the balloon is joined to the optical fiber.

3. 3. The balloon catheter according to claim 1, wherein the length of the second shaft in the longitudinal direction is 10 times or more the minimum outer diameter of the second shaft.

4. 4. The balloon catheter according to claim 1, wherein in a cross section perpendicular to the longitudinal direction at the proximal end of the second shaft, the position of a central axis of the outer shape of the second shaft is different from the position of a central axis of the outer shape of the optical fiber.

5. 5. The balloon catheter according to claim 1, wherein in a cross section perpendicular to the longitudinal direction of the second shaft, an area of ​​a gap formed between the inner surface of the second shaft and the outer surface of the optical fiber is 40% or more of an area of ​​an inner cavity of the second shaft.

6. 6. The balloon catheter according to claim 1, wherein the inner surface of the second shaft has a protrusion that comes into contact with the outer surface of the optical fiber.

7. A tip is disposed on the distal side of the optical fiber, The balloon catheter according to any one of claims 1 to 6, wherein the distal end of the tip is located distal to the distal end of the balloon.

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