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 a tubular member (40) that is disposed within the balloon (30) and that has a light transmittance of 90% or greater. 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 proximal end (40p) of the tubular member (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 tubular member (40).

Description

[Technical Field]

[0001] The present invention relates to a balloon catheter used 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, allowing it to accumulate in target tissues such as cancer cells. The photosensitizer is 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. Laser ablation (tissue cauterization) involves irradiating the target tissue with laser light to cauterize it.

[0003] Photoirradiation medical devices are used in PDT and laser ablation to irradiate the treatment area, which is the target tissue such as cancer cells in the body lumen, such as blood vessels or the digestive tract, with light of a specific wavelength. 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 endoscopic treatment, 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 emitting end disposed within the balloon member near the distal end and fixed to the tubular substrate. It also describes that in the balloon catheter with a light guide device, the light guide device extends within the duct of the tubular substrate, and the outer wall of the end of the tubular substrate extends into the balloon member and defines the duct, with at least a portion of it having been removed in advance to expose the light emitting end of the light guide device within the balloon member, and that an optical fiber is used for the light emitting end.

[0006] Patent Document 2 describes a laser fiber guide catheter 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 is provided inside the inner tube into which a laser fiber can be inserted, 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 at the center of the balloon, or two locations 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 at 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] Japanese Patent Application Laid-Open No. 2009-160446 Summary of the Invention [Problem to be solved by the invention]

[0008] However, with the balloon catheters of Patent Documents 1 and 2, when the balloon catheter is pulled toward the proximal end to remove it from an endoscope, the force of pulling the balloon catheter toward the proximal end is not easily transmitted to the distal end of the balloon, making it difficult to remove the balloon catheter from the endoscope.

[0009] Furthermore, in the balloon catheters of Patent Documents 1 and 2, the optical fiber also bends when the balloon catheter is placed in a curved body lumen. Furthermore, when the balloon catheters of Patent Documents 1 and 2 are placed in a body lumen, the balloon is constrained by the body lumen, and the balloon is compressed, shortening its axial length, which also bends the optical fiber. This causes the optical fiber inside the balloon to be positioned off the center of the cross section of the balloon perpendicular to the longitudinal direction, resulting in insufficient light irradiation of the target tissue and insufficient photodynamic therapy. Furthermore, there are also problems in that the target tissue may be irradiated with more intense light than expected, resulting in perforation of the body tissue.

[0010] The present invention has been made in consideration of the above circumstances, and its object is to provide a balloon catheter that is easily removable from an endoscope or the like, and in which the optical fiber is positioned 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 disposed distally of the first shaft, a balloon disposed distally of the second shaft, and a tubular member disposed inside the balloon and having a light transmittance of 90% or more; the material constituting the first shaft is a resin; 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 proximal end of the tubular member 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 tubular member.

[0012] The second balloon catheter, which can solve the above problem, comprises a first shaft having an inner cylindrical portion with a first lumen and a second lumen, a second shaft disposed distally of the first shaft, a balloon disposed distally of the second shaft, and a tubular member disposed inside the balloon and having a light transmittance of 90% or more, wherein at least a portion of the outer surface of the inner cylindrical portion is fixed to the inner surface of the first shaft, the proximal end of the tubular member 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 tubular member.

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

[0014] In the balloon catheter of the present invention, it is preferable that 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 tubular member in a cross section perpendicular to the longitudinal direction at the proximal end of the second shaft.

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

[0016] In the balloon catheter of the present invention, an optical fiber is preferably disposed in the lumen of the tubular member.

[0017] In the balloon catheter of the present invention, the distal end of the tubular member is preferably closed.

[0018] In the balloon catheter of the present invention, the inner surface of the second shaft preferably has protrusions that come into contact with the outer surface of the tubular member. [Effects of the Invention]

[0019] 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 larger cross-sectional area of ​​either the first lumen or the second lumen. The proximal end of the tubular member 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 tubular member. This facilitates the transfer of force applied to both the proximal and distal ends of the balloon. This improves the ease of removal of the balloon catheter from an endoscope, etc. Furthermore, the tubular member in which the optical fiber is disposed is joined not to the proximal end of the balloon but to the distal end of the first lumen, which is located proximal to the proximal end of the balloon. This allows the tubular member to move freely between the distal end of the balloon and the distal end of the first lumen without being fixed to any other object. As a result, the optical fiber can be positioned in the center of the cross section of the balloon perpendicular to the longitudinal direction, even when the balloon catheter shaft is bent or the balloon is compressed.

[0020] According to a second balloon catheter of the present invention, the first shaft includes an inner cylindrical portion having a first lumen and a second lumen, at least a portion of the outer surface of the inner cylindrical portion is fixed to the inner surface of the first shaft, the proximal end of the tubular member 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 tubular member. This facilitates the transfer of pulling force to the proximal and distal ends of the balloon when removing the balloon catheter from an endoscope, facilitating removal of the balloon catheter from an endoscope. Furthermore, because the tubular member is joined to the distal end of the inner cylindrical portion, the tubular member can move freely longitudinally from the distal end of the balloon to the distal end of the first lumen without being fixed to any other object. Therefore, by disposing an optical fiber in the lumen of the tubular member, the optical fiber can be positioned in the center of the cross section of the balloon perpendicular to the longitudinal direction, even when the balloon catheter shaft is bent or the balloon is compressed. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a longitudinal cross-sectional view of a first balloon catheter according to an embodiment of the present invention. [Figure 2] 2 is a cross-sectional view of the balloon catheter shown in FIG. 1 taken along line II-II. [Figure 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 shows a cross-sectional view of the balloon catheter shown in FIG. 3 taken along line IV-IV. [Figure 5] 10 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. DETAILED DESCRIPTION OF THE INVENTION

[0022] The present invention will be described in more detail below based on the following embodiments. However, the present invention is not limited to the following embodiments, and can be implemented with appropriate modifications within the scope of the above and below-described purposes, and all such modifications are included within the technical scope of the present invention. For convenience, hatching and component symbols may be omitted in the drawings. In such cases, reference should be made to the specification or other drawings. The dimensions of various components in the drawings may differ from actual dimensions, as priority is given to helping understand the features of the present invention.

[0023] First, the first balloon catheter of the present invention will be described.

[0024] 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 cross-sectional view taken along line II-II 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 comprises a first shaft 10 having a first lumen 11 and a second lumen 12, a second shaft 20 disposed distally of the first shaft 10, a balloon 30 disposed distally of the second shaft 20, and a tubular member 40 disposed inside the balloon 30 and having an optical transmittance of 90% or more, wherein a proximal end 40p of the tubular member 40 is joined to a distal end 11d of the first lumen 11, a proximal end 30p of the balloon 30 is joined to the second shaft 20, and a distal end 30d of the balloon 30 is joined to the tubular member 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 the cross-sectional area of ​​either the first lumen 11 or the second lumen 12.

[0025] 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. The proximal end 40p of the tubular member 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 tubular member 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 tubular member 40. This facilitates the transfer of the pulling force of the first shaft 10 to both the proximal end 30p and the distal end 30d of the balloon 30. This improves the ease of removal of the balloon catheter 1 from an endoscope or the like.

[0026] Furthermore, because the proximal end 40p of the tubular member 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 tubular member 40, the tubular member 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 tubular member 40 is not fixed to any object between the distal end 30d of the balloon 30 and the distal end 11d of the first lumen 11, and the tubular member 40 can freely change position and bend in accordance with the bending state of the balloon catheter 1. As a result, when photodynamic therapy is performed by irradiating light onto target tissue, with an optical fiber inserted through the tubular member 40, the optical fiber can be positioned in the center of the cross section of the balloon 30 perpendicular to the longitudinal direction, facilitating photodynamic therapy.

[0027] 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 tubular member 40.

[0028] The joining of the tubular member 40 and the first lumen 11, the joining of the balloon 30 and the second shaft 20, and the joining of the balloon 30 and the tubular member 40 may be performed directly or via another member. The joining of the tubular member 40 and the first lumen 11, the joining of the balloon 30 and the second shaft 20, and the joining of the balloon 30 and the tubular member 40 can be performed by, for example, welding, adhesion, or the like.

[0029] In the present invention, the proximal side refers to the side of the user, i.e., the hand side of the surgeon, relative to 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 also be referred to as the direction of distance of the first shaft 10.

[0030] 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 distal end 11d of the first lumen 11 is joined to a tubular member 40, and an optical fiber, a stylet, etc. can be placed inside the first lumen 11 and the tubular member 40. 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.

[0031] The first shaft 10 is only 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, which makes it easier to insert the balloon catheter 1 into the body.

[0033] The material constituting the first shaft 10 is resin, and as shown in FIG. 2 , in a cross section perpendicular to the longitudinal direction, the cross-sectional area of ​​the resin constituting the first shaft 10 is larger than either the larger cross-sectional area of ​​the first lumen 11 or 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 constituting the first shaft 10. Note that if the cross-sectional areas of the first lumen 11 and the second lumen 12 are the same, either the cross-sectional area of ​​the first lumen 11 or the cross-sectional area of ​​the second lumen 12 may be used for comparison with the cross-sectional area of ​​the resin constituting the first shaft 10. By having the cross-sectional area of ​​the resin constituting the first shaft 10 larger than either the larger cross-sectional area of ​​the first lumen 11 or 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 it or a force pulling the balloon catheter 1 when removing it is applied to the first shaft 10, this force is more easily transmitted to the distal end 30d and proximal end 30p of the balloon 30 through the first shaft 10, thereby 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 first shaft 10 is preferably at least 1.1 times, more preferably at least 1.2 times, and even more preferably at least 1.3 times the cross-sectional area of ​​either the larger of first lumen 11 or second lumen 12. By setting the lower limit of the ratio of the cross-sectional area of ​​the resin forming first shaft 10 to the cross-sectional area of ​​either the larger of first lumen 11 or second lumen 12 within the above range, it is possible to sufficiently increase the rigidity of first shaft 10. Furthermore, the cross-sectional area of ​​the resin forming first shaft 10 is preferably at most 5 times, more preferably at most 4 times, and even more preferably at most 3 times the cross-sectional area of ​​either the larger of first lumen 11 or second lumen 12. By setting the upper limit of the ratio between the cross-sectional area of ​​the resin forming the first shaft 10 and the larger cross-sectional area of ​​either 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 an optical fiber, stylet, etc. into the first lumen 11 and the supply and removal of fluid for expanding the balloon 30 into and from the second lumen 12 can be smoothly performed.

[0035] Examples of materials constituting the first shaft 10 include synthetic resins such as polyolefin resins (e.g., polyethylene, polypropylene, etc.), polyamide resins (e.g., nylon, etc.), polyester resins (e.g., PET, etc.), aromatic polyetherketone resins (e.g., PEEK, etc.), vinyl chloride resins, polyetherpolyamide resins, polyurethane resins, polyimide resins, and fluorine-based resins (e.g., PTFE, PFA, ETFE, etc.). These materials may be used alone or in combination of two or more. Among these, it is preferable that the material constituting the first shaft 10 contains a polyolefin resin, a polyamide resin, or a fluorine-based resin. By using a material constituting the first shaft 10 that contains a polyolefin resin, a polyamide resin, or a fluorine-based resin, the first shaft 10 is flexible and the surface of the first shaft 10 has improved slipperiness, resulting in a balloon catheter 1 with good insertability.

[0036] As shown in FIG. 1 , the second shaft 20 extends in the longitudinal direction and has a tubular structure with a lumen. The second shaft 20 is disposed distal to the first shaft 10. That is, the second shaft 20 is disposed distal to the distal end 10d of the first shaft 10. A tubular member 40 is disposed in the lumen of the second shaft 20. The second shaft 20 is preferably flexible. The flexibility of the second shaft 20 makes the second shaft 20 soft, which allows the balloon catheter 1 to be easily inserted.

[0037] The second shaft 20 may be composed of multiple 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 lumen in the body, the second shaft 20 bends easily, improving the insertability of the balloon catheter 1.

[0038] Examples of materials constituting the second shaft 20 include synthetic resins such as polyolefin resins (e.g., polyethylene, polypropylene, etc.), polyamide resins (e.g., nylon, etc.), polyester resins (e.g., PET, etc.), aromatic polyetherketone resins (e.g., PEEK, etc.), vinyl chloride resins, polyetherpolyamide resins, polyurethane resins, polyimide resins, fluorine-containing resins (e.g., PTFE, PFA, ETFE, etc.), and metals (e.g., stainless steel, carbon steel, nickel-titanium alloy, etc.). These materials may be used alone or in combination. It is preferable that the material constituting the second shaft 20 contains the same material as the material constituting the first shaft 10. By using the same material as the material constituting the first shaft 10, the physical properties of the first shaft 10 and the second shaft 20, such as hardness and surface smoothness, become similar, resulting in a balloon catheter 1 that is easily insertable into the body. Furthermore, when the first shaft 10 and the second shaft 20 are directly joined, the bond strength between the first shaft 10 and the second shaft 20 can be increased.

[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. Furthermore, 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 tubular member 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 so that fluid is supplied to the interior of the balloon 30 from a fluid supplier through the first shaft 10 and the second shaft 20. By supplying fluid to the interior of the balloon 30, the balloon 30 can be expanded. Furthermore, by removing the fluid from the interior of the balloon 30 from the balloon 30, the balloon 30 can be deflated. 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 interior of the balloon 30 may be pressurized fluid pressurized by a pump or the like.

[0041] The type of fluid that can be 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 be a gas. By using a gas as the fluid supplied into the balloon 30, the fluid present inside the balloon 30 is less likely to interfere with the light emitted from the optical fiber 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 inside the body. This makes it possible to fix the balloon 30 to the lumen inside the body, facilitating photodynamic therapy.

[0043] The balloon 30 has a proximal tapered portion connected to the straight tube portion 31 proximal to the proximal end 31p of the straight tube portion 31, and a distal tapered portion connected to the straight tube portion 31 distal to the distal end 31d of the straight tube portion 31. More preferably, the proximal tapered portion and the distal tapered portion are formed so that their diameters decrease with increasing distance from the straight tube portion 31. By having the proximal tapered portion and the distal tapered portion formed so that their diameters decrease with increasing distance from the straight tube portion 31, the strength of the balloon 30 can be increased, making the balloon 30 less likely to break when force is applied to the balloon 30. Furthermore, the step that occurs when the balloon 30 is wrapped around a shaft can be reduced, making it easier to insert the balloon 30 into a lumen in the body. The balloon 30 can be configured so that the distal tapered portion expands when a fluid is supplied from the proximal tapered portion through the straight tube portion 31. In the present invention, the expandable portion is considered to be the balloon 30.

[0044] Examples of materials 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-based resins; silicone resins; and natural rubbers such as latex rubber. These materials may be used alone or in combination. Among these, polyamide resins, polyester resins, and polyurethane resins are preferred as the material constituting the balloon 30. Using polyamide resins, polyester resins, or polyurethane resins as the material constituting the balloon 30 allows for a thinner balloon 30 and improved flexibility.

[0045] 1, the tubular member 40 extends in the longitudinal direction and has an inner cavity. The tubular member 40 is disposed inside the balloon 30, and a proximal end 40p of the tubular member 40 is joined to the distal end 11d of the first lumen 11. An optical fiber, a stylet, or the like can be disposed inside the tubular member 40.

[0046] Because the balloon catheter 1 has the tubular member 40, when photodynamic therapy is performed using the balloon catheter 1 with an optical fiber disposed inside the tubular member 40, the path through which the fluid for inflating the balloon 30 passes can be separate from the path through which the optical fiber is inserted. This prevents contact between the fluid for inflating the balloon 30 and the optical fiber, making it less likely that the fluid for inflating the balloon 30 will have adverse effects, such as deterioration of the optical fiber. Furthermore, the photodynamic therapy procedure can be performed smoothly and the time required for the procedure can be shortened, for example, by inserting a stylet into the tubular member 40 to deliver the balloon catheter 1 to the treatment site, and then removing the stylet from the tubular member 40 and inserting the optical fiber.

[0047] The tubular member 40 may have a light transmittance of 90% or more, preferably 91% or more, more preferably 93% or more, and even more preferably 95% or more. By setting the lower limit of the light transmittance of the tubular member 40 within the above range, when an optical fiber is placed inside the tubular member 40, light emitted from the optical fiber can easily pass through the tubular member 40, allowing photodynamic therapy to be performed efficiently. The upper limit of the light transmittance of the tubular member 40 is not particularly limited, and can be, for example, 100% or less.

[0048] Examples of materials constituting the tubular member 40 include polyolefin-based resins such as polyethylene, polypropylene, and ethylene-propylene copolymer; polyester-based resins such as polyethylene terephthalate and polyester elastomer; polyurethane-based resins such as polyurethane and polyurethane elastomer; polyphenylene sulfide-based resins; polyamide-based resins such as polyamide and polyamide elastomer; vinyl chloride-based resins; fluorine-based resins; silicone-based resins; and natural rubbers such as latex rubber. These materials may be used alone or in combination. Among these, the material constituting the tubular member 40 preferably contains a polyamide-based resin, a polyester-based resin, a polyurethane-based resin, a polyolefin-based resin, or a fluorine-based resin. By including a polyamide-based resin, a polyester-based resin, a polyurethane-based resin, a polyolefin-based resin, or a fluorine-based resin in the material constituting the tubular member 40, the lubricity of the surface of the tubular member 40 can be improved, facilitating the insertion and removal of optical fibers, stylets, and the like into and from the tubular member 40.

[0049] The tubular member 40 is preferably flexible. When the tubular member 40 is flexible, the tubular member 40 becomes soft and easily bends when the balloon catheter 1 is inserted into a curved lumen in the body. This improves the insertability of the balloon catheter 1 into the body.

[0050] As shown in FIG. 1 , the distal end 40d of the tubular member 40 is preferably located distal to the distal end 30d of the balloon 30. Having the distal end 40d of the tubular member 40 located distal to the distal end 30d of the balloon 30 increases the rigidity of the distal end of the balloon catheter 1, thereby facilitating insertion of the balloon catheter 1 into the body. Furthermore, having the distal end 40d of the tubular member 40 located distal to the distal end 30d of the balloon 30 ensures that the tubular member 40 extends over the entire longitudinal length of the balloon 30. As a result, when an optical fiber is disposed within the tubular member 40, the optical fiber can be positioned along the entire straight tube portion 31 of the balloon 30 in the longitudinal direction, facilitating photodynamic therapy.

[0051] 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 passageway for an optical fiber, a stylet, or the like that is inserted into the lumen of the tubular member 40. The handle portion also preferably has a lumen that is equipped with 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 fluid for inflating the balloon 30.

[0052] 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. Joining the proximal end 20p of the second shaft 20 to the distal end 10d of the first shaft 10 makes it 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.

[0053] Next, a second balloon catheter of the present invention will be described. In the description of the second balloon catheter, parts that overlap with the above description will be omitted.

[0054] Fig. 3 is a longitudinal cross-sectional view of a second balloon catheter 1 according to an 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 Figs. 3 and 4, the 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.

[0055] The first shaft 10 includes an inner cylindrical portion 50 having a first lumen 11 and a second lumen 12, 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, the proximal end 40p of the tubular member 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 tubular member 40, thereby providing a structure in which 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 tubular member 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 is easily transmitted to both the distal end 30d and the proximal end 30p of the balloon 30, improving the ease of removal of the balloon catheter 1. It is preferable that the proximal end 30p of the balloon 30 is joined to the distal end 20d of the second shaft 20, and the distal end 30d of the balloon 30 is joined to the distal end 40d of the tubular member 40.

[0056] Furthermore, because the proximal end 40p of the tubular member 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 tubular member 40, the tubular member 40 is not fixed to any object in the longitudinal direction of the balloon catheter 1 between the distal end 30d of the balloon 30 and the distal end 11d of the first lumen 11, and the tubular member 40 can freely change position and bend in accordance with the bending state of the balloon catheter 1. Therefore, when performing photodynamic therapy by irradiating target tissue with light, with an optical fiber inserted through the tubular member 40, the optical fiber can be positioned in the center of the cross section of the balloon 30 perpendicular to the longitudinal direction, making photodynamic therapy easier to perform.

[0057] 3, the inner cylindrical portion 50 extends in the longitudinal direction. The inner cylindrical portion 50 is joined to the tubular member 40, and an optical fiber, a stylet, etc. can be placed in the lumen of the tubular member 40 through the inner cylindrical portion 50.

[0058] 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, fixing via other components, and the like.

[0059] As shown in FIGS. 1 and 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 refers to the longitudinal distance between the distal end 20d of the second shaft 20 and the proximal end 20p of the second shaft 20. By making the length L1 of the second shaft 20 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 tubular member 40 to the distal end 11d of the first lumen 11 joined to the proximal end 40p of the tubular member 40 can be increased. In other words, the distance between the two points where the tubular member 40 is joined to another object can be increased, allowing the tubular member 40 to freely change position and bend in accordance with the bending state of the balloon catheter 1 in the portion where the tubular member 40 is not joined to another object. As a result, the tubular member 40 is positioned at the center of the cross section of the balloon 30 perpendicular to the longitudinal direction, and when an optical fiber is inserted into the inner cavity of the tubular member 40, the optical fiber is more likely to be positioned at the center of the balloon 30, allowing photodynamic therapy to be performed efficiently.

[0060] 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 of the length L1 of the second shaft 20 to the minimum outer diameter of the second shaft 20 within the above range, it is possible to ensure a sufficient distance from the distal end 30d of the balloon 30 joined to the tubular member 40 to the distal end 11d of the first lumen 11 joined to the proximal end 40p of the tubular member 40. Furthermore, the upper limit of the ratio of the length L1 of the second shaft 20 to 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.

[0061] 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 is preferably different from the position of the central axis C40 of the outer shape of the tubular member 40. The difference between 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 tubular member 40 allows the tubular member 40 to easily change position and bend within the respective lumens of the second shaft 20 and the balloon 30. Therefore, when the balloon catheter 1 is inserted into a curved body lumen, the tubular member 40 easily moves in accordance with the bending state of the balloon catheter 1, and the tubular member 40 is likely to be positioned at the center of the cross section of the balloon 30 perpendicular to the longitudinal direction. As a result, when an optical fiber is inserted into the tubular member 40, the optical fiber is positioned at the center of the balloon 30, facilitating photodynamic therapy.

[0062] 4, in a cross section perpendicular to the longitudinal direction of the second shaft 20, the cross-sectional area of ​​the gap formed between the inner surface of the second shaft 20 and the outer surface of the tubular member 40 is preferably 40% or more of the cross-sectional area of ​​the lumen of the second shaft 20. By having the cross-sectional area of ​​the gap formed between the inner surface of the second shaft 20 and the outer surface of the tubular member 40 be 40% or more of the cross-sectional area of ​​the lumen of the second shaft 20, the tubular member 40 can move freely within the second shaft 20. Therefore, even when the second shaft 20 is bent, the optical fiber arranged in the lumen of the tubular member 40 is likely to be positioned at the center of the cross section of the balloon 30 perpendicular to the longitudinal direction, facilitating photodynamic therapy.

[0063] In a cross section perpendicular to the longitudinal direction of the second shaft 20, the cross-sectional area of ​​the gap formed between the inner surface of the second shaft 20 and the outer surface of the tubular member 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 formed between the inner surface of the second shaft 20 and the outer surface of the tubular member 40 to the cross-sectional area of ​​the lumen of the second shaft 20 within the above range, the tubular member 40 can move more freely in the lumen of the second shaft 20. Furthermore, the upper limit of the ratio of the cross-sectional area of ​​the gap formed between the inner surface of the second shaft 20 and the outer surface of the tubular member 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.

[0064] Although not shown, it is preferable that an optical fiber be disposed in the lumen of tubular member 40. Disposing an optical fiber in the lumen of tubular member 40 allows balloon catheter 1 to be used for photodynamic therapy, and also prevents the fluid that expands balloon 30 from coming into contact with the optical fiber, making it less likely that the fluid that expands balloon 30 will have adverse effects, such as deterioration of the optical fiber.

[0065] An optical fiber is preferably provided in the lumen of the tubular member 40, and the optical fiber is fixed to the tubular member 40 distal to the straight tube portion 31 of the balloon 30. The light intensity at the tip of the optical fiber is weak, and may be insufficient for photodynamic therapy. To supply a sufficient amount of light to the balloon 30, the optical fiber is preferably fixed distal to the straight tube portion 31 of the balloon 30 or distal to the distal tapered portion of the balloon 30. Fixing the optical fiber distal to the straight tube portion 31 or distal to the distal tapered portion of the balloon 30 ensures a sufficient amount of light for photodynamic therapy. Furthermore, if light is to be supplied from the optical fiber to the straight tube portion 31 of the balloon 30 but not to the tapered portion of the balloon 30, it is possible to irradiate the desired area with light by, for example, appropriately placing a covering material on the optical fiber.

[0066] The optical fiber is preferably fixed to the tubular member 40 distal to the distal tapered portion of the balloon 30. By fixing the optical fiber to the tubular member 40 distal to the distal tapered portion of the balloon 30, a sufficient amount of light can be ensured for photodynamic therapy. Furthermore, by having the distal end of the optical fiber distal to the distal end 30d of the balloon 30, the rigidity of the distal end of the balloon catheter 1 is increased, making it easier to insert the balloon catheter 1 into the body.

[0067] It is also preferable that the optical fiber be fixed to the tubular member 40 proximal to the distal end 60d of the tip 60, which will be described later. Fixing the optical fiber to the tubular member 40 proximal to the distal end 60d of the tip 60 ensures a sufficient amount of light for photodynamic therapy. Furthermore, the hardness of the distal end 60d of the tip 60 is less likely to increase, which can prevent the balloon catheter 1 from perforating the body lumen.

[0068] 1 and 3, the distal end 40d of the tubular member 40 is preferably closed. By closing the distal end 40d of the tubular member 40, when the balloon catheter 1 is placed in a lumen of the body, for example, gastrointestinal mucus, blood, etc. can be prevented from entering the tubular member 40 through the distal end 40d of the tubular member 40. As a result, adverse effects such as deterioration of the optical fiber due to contact of gastrointestinal mucus, blood, etc. with the optical fiber or stylet placed in the lumen of the tubular member 40 can be prevented.

[0069] Methods for occluding the distal end 40d of the tubular member 40 include, for example, providing a separate component such as a distal tip 60 at the distal end 40d of the tubular member 40, pouring adhesive or the like into the distal end 40d of the tubular member 40, or crushing the distal end 40d of the tubular member 40. Among these methods, as shown in FIG. 1 , it is preferable to occlude the distal end 40d of the tubular member 40 by providing a distal tip 60 at the distal end 40d of the tubular member 40. By providing the distal tip 60 at the distal end 40d of the tubular member 40, the rigidity of the distal end 40d of the tubular member 40 is increased. As a result, the rigidity of the distal end portion of the balloon catheter 1 is also increased, thereby improving the insertability of the balloon catheter 1.

[0070] When the distal tip 60 is provided at the distal end 40d of the tubular member 40, the color of the distal tip 60 is preferably different from the color of the tubular member 40. "The color of the distal tip 60 is different from the color of the tubular member 40" means that at least one of the hue, brightness, and saturation defined by JIS Z8721 is different. When the color of the distal tip 60 is different from the color of the tubular member 40, the distal tip 60 becomes easier to see under an endoscope. As a result, it becomes easier to confirm the position of the distal tip 60 and the balloon 30 in the body lumen.

[0071] Figure 5 is a cross-sectional view perpendicular to the longitudinal direction of the second shaft 20 of a balloon catheter 1 according to another embodiment of the present invention. As shown in Figure 5, the inner surface of the second shaft 20 preferably has a protrusion 70 that contacts the outer surface of the tubular member 40. By providing the protrusion 70 on the inner surface of the second shaft 20, the protrusion 70 can determine the position of the tubular member 40 within the second shaft 20. As a result, the position of the tubular member 40 can be restricted so as not to deviate significantly from the central axis of the balloon 30. Note that the protrusion 70 is not joined to the tubular member 40.

[0072] The protrusions 70 are preferably disposed on the inner surface of the distal end of the second shaft 20. By disposing the protrusions 70, which come into contact with the outer surface of the tubular member 40, on the inner surface of the distal end of the second shaft 20 so that the tubular member 40 is located at the center of a cross section perpendicular to the longitudinal direction of the second shaft 20, the tubular member 40 is more 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 tubular member 40 is more likely to be located at the center of the balloon 30, which is disposed distally of the second shaft 20 and joined to the second shaft 20, and the balloon catheter 1 can be made to facilitate photodynamic therapy.

[0073] 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 tubular member 40 within the second shaft 20 can be more easily regulated by the protrusions 70.

[0074] As described above, the first balloon catheter of the present invention comprises 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, and a tubular member disposed inside the balloon and having an optical transmittance of 90% or more, 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 ​​either the first lumen or the second lumen, the proximal end of the tubular member 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 tubular member. 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 proximal end of the tubular member 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 tubular member. This facilitates force transfer to both the proximal and distal ends of the balloon. This improves the ease of removal of the balloon catheter from an endoscope. Furthermore, the tubular member in which the optical fiber is disposed is joined not to the proximal end of the balloon but to the distal end of the first lumen, which is located proximal to the proximal end of the balloon. This allows the tubular member to move freely between the distal end of the balloon and the distal end of the first lumen without being fixed to any other object. As a result, the optical fiber can be positioned in the center of the cross section of the balloon perpendicular to the longitudinal direction, even when the balloon catheter shaft is bent or the balloon is compressed.

[0075] Furthermore, a second balloon catheter of the present invention comprises a first shaft having an inner cylindrical portion with a first lumen and a second lumen, a second shaft disposed distally of the first shaft, a balloon disposed distally of the second shaft, and a tubular member disposed inside the balloon and having an optical transmittance of 90% or more, wherein at least a portion of the outer surface of the inner cylindrical portion is fixed to the inner surface of the first shaft, the proximal end of the tubular member 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 tubular member. The first shaft includes an inner cylindrical portion having a first lumen and a second lumen, at least a portion of the outer surface of the inner cylindrical portion is fixed to the inner surface of the first shaft, the proximal end of the tubular member 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 tubular member. This facilitates the transfer of the pulling force of the balloon catheter to the proximal and distal ends of the balloon when removing the balloon catheter from an endoscope, making it easier to remove the balloon catheter from an endoscope. Furthermore, because the tubular member is joined to the distal end of the first lumen, the tubular member is not fixed to anything in the longitudinal direction between the distal end of the balloon and the distal end of the first lumen, allowing it to move freely. Therefore, by disposing an optical fiber in the lumen of the tubular member, it is possible to position the optical fiber in the center of the cross section of the balloon perpendicular to the longitudinal direction, even when the balloon catheter shaft is bent or the balloon is compressed.

[0076] This application claims the benefit of priority to Japanese Patent Application No. 2020-039081, filed on March 6, 2020. The entire content of the specification of Japanese Patent Application No. 2020-039081, filed on March 6, 2020, is incorporated herein by reference. [Explanation of symbols]

[0077] 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: Second lumen 20: Second 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 pipe section 40: Tubular member 40d: Distal end of tubular member 40p: Proximal end of tubular member 50: Inner cylinder 50d: Distal end of inner cylinder 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 outer shape of the tubular member

Claims

1. 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; a tubular member disposed inside the balloon and having a light transmittance of 90% or more; an optical fiber connected to a light source is disposed in the lumen of the tubular member; 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, a proximal end of the tubular member joined to a distal end of the first lumen; a proximal end of the balloon attached to the second shaft; a distal end of the balloon joined to the tubular member; A balloon catheter, wherein the distal end of the tubular member is closed.

2. 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; a tubular member disposed inside the balloon and having a light transmittance of 90% or more; an optical fiber connected to a light source is disposed in the lumen of the tubular member; At least a portion of an outer surface of the inner cylindrical portion is fixed to an inner surface of the first shaft, a proximal end of the tubular member joined to a distal end of the inner cylindrical portion; a proximal end of the balloon attached to the second shaft; a distal end of the balloon joined to the tubular member; A balloon catheter, wherein the distal end of the tubular member is closed.

3. 3. The balloon catheter according to claim 1, wherein the length of the second shaft in the longitudinal direction is at least 10 times 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 the central axis of the outer shape of the second shaft is different from the position of the central axis of the outer shape of the tubular member.

5. 5. The balloon catheter according to claim 1, wherein in a cross section perpendicular to the longitudinal direction of the second shaft, the cross-sectional area of ​​a gap formed by the inner surface of the second shaft and the outer surface of the tubular member is 40% or more of the cross-sectional area of ​​the lumen 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 tubular member.

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