Cryoablation catheter

Abstract

To provide a cryoablation catheter capable of smoothly removing a balloon after cooling target tissue is over while preventing the cooled tissue from being damaged.SOLUTION: A cryoablation catheter 100 has: a supply lumen 31 which extends in a longitudinal direction x of the cryoablation catheter 100 and in which fluid can pass from a proximal end to a distal end; a balloon 40 with which fluid passing the supply lumen 31 is supplied; a discharge flow path 21 which is located in an area different from the supply lumen 31 in a radial direction y of the cryoablation catheter 100, extends in the longitudinal direction x of the cryoablation catheter 100, and in which the fluid passing the inner part 401 of the balloon 40 is passable from the distal side to the proximal side; and a light emitting part 60 disposed in the inner part 401 of the balloon 40.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a cryoablation catheter. [Background technology]

[0002] Cryoablation is a medical technique that involves contacting a cryogenic device with the target tissue to freeze and kill the cells that make up the tissue, and is used to treat cardiac muscle tissue and tumor tissue. Methods for cryostating the device include using liquid nitrogen and using the Joule-Thomson effect with high-pressure gas.

[0003] Patent Document 1 describes a cryosurgery catheter having a catheter body with a proximal end, a distal end, and a main lumen extending therethrough. A balloon containing a cryogenic fluid supplied through the main lumen is mounted on an orifice of the catheter body constituting the cryosurgery catheter. The balloon is inflated by supplying the cryogenic fluid through the catheter body, thereby cooling the affected area. More specifically, the document discloses a configuration in which the cryogenic fluid transported from the proximal side to the distal side by a cryogenic supply tube is supplied into the balloon through a port formed in a diffuser, and the cryogenic fluid is then discharged through an outlet lumen. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2001-524345 Summary of the Invention [Problem to be solved by the invention]

[0005] In the cryosurgery catheter described in Patent Document 1, a fluid is conveyed through the main lumen to the balloon, thereby cooling the target tissue. After the cooling of the target tissue is complete, the balloon must be removed. However, because the balloon is difficult to separate from the tissue after cooling, removing the balloon can take a long time, and there is also the problem of the possibility of damaging the tissue after cooling.

[0006] The present invention has been made in consideration of the above circumstances, and its object is to provide a cryoablation catheter that can easily and smoothly remove the balloon after cooling of the target tissue has been completed, while preventing damage to the cooled tissue. [Means for solving the problem]

[0007] A cryoablation catheter according to one embodiment of the present invention is as follows. [1] A cryoablation catheter having a longitudinal direction and a radial direction, a supply lumen extending in the longitudinal direction and allowing fluid to pass from the proximal side to the distal side; a balloon to which the fluid that has passed through the supply lumen is supplied; a discharge flow path that is located in a region different from the supply lumen in the radial direction, extends in the longitudinal direction, and allows a fluid that has passed through the interior of the balloon to pass from the distal side to the proximal side; a light emitting unit disposed inside the balloon; A cryoablation catheter having:

[0008] The target tissue is cooled by the fluid being transported through the supply lumen to the balloon. After the cooling of the target tissue is complete, light is emitted from a light-emitting unit disposed inside the balloon. This allows the balloon and / or the tissue surrounding the balloon to be heated, making it easier to detach the balloon from the target tissue. Therefore, after the cooling of the target tissue is complete, the balloon can be easily removed without damaging the cooled tissue.

[0009] The cryoablation catheter according to the embodiment of the present invention is preferably any one of the following [2] to

[11] . [2] The cryoablation catheter according to [1], wherein the light emitted from the light-emitting unit includes light having a wavelength of 600 nm or more and 2500 nm or less. [3] A cryoablation catheter according to [1] or [2], wherein the balloon has a first portion and a second portion having a higher absorption rate of light emitted by a specific light-emitting element than the first portion. [4] The balloon has a straight tube portion, a distal tapered portion located distal to the straight tube portion and having an outer diameter that decreases toward the distal side, and a proximal tapered portion located proximal to the straight tube portion and having an outer diameter that decreases toward the proximal side, The cryoablation catheter according to [3], wherein the second portion is located in the straight tube portion. [5] The cryoablation catheter according to any one of [1] to [4], wherein the balloon has an outer balloon and an inner balloon disposed inside the outer balloon. [6] The balloon has a first layer disposed between the outer balloon and the inner balloon, [5] A cryoablation catheter as described in [5], wherein the absorption rate of light emitted by the specific light-emitting member in the first layer is greater than the absorption rate of light emitted by the specific light-emitting member in the outer balloon and the absorption rate of light emitted by the specific light-emitting member in the inner balloon. [7] A cryoablation catheter as described in [6], wherein the balloon is positioned between the outer balloon and the inner balloon and has a second layer that is radiopaque. [8] A cryoablation catheter according to [7], wherein the second layer is located closer to the outer balloon than the first layer. [9] The balloon has a straight tube portion, a distal tapered portion located distal to the straight tube portion and having an outer diameter that decreases toward the distal side, and a proximal tapered portion located proximal to the straight tube portion and having an outer diameter that decreases toward the proximal side, The cryoablation catheter according to [7] or [8], wherein the first layer and the second layer are located in the straight tube portion.

[10] The cryoablation catheter includes an outer shaft having a lumen extending in the longitudinal direction, and an inner shaft disposed in the lumen of the outer shaft, the supply lumen is formed in the inner shaft; The cryoablation catheter according to any one of [1] to [9], wherein the discharge flow path is a space existing between the outer surface of the inner shaft and the inner surface of the outer shaft.

[11] The cryoablation catheter according to

[10] , wherein the inner shaft has a hole that connects the supply lumen to the interior of the balloon. [Effects of the Invention]

[0010] The cryoablation catheter of the present invention makes it possible to easily and smoothly remove the balloon after cooling of the target tissue has been completed, while preventing damage to the cooled tissue. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a side view of a cryoablation catheter according to an embodiment of the present invention. [Figure 2] FIG. 2 shows a cross-sectional view of the distal portion of the cryoablation catheter shown in FIG. [Figure 3] FIG. 3 is a cross-sectional end view of the cryoablation catheter shown in FIG. 2 taken along line III-III. [Figure 4] FIG. 4 is a cross-sectional view (partial side view) showing a modification of the cryoablation catheter shown in FIG. [Figure 5] FIG. 5 is a cross-sectional end view of the cryoablation catheter shown in FIG. 4 taken along line VV. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present invention will be described in detail below with reference to the drawings. However, the present invention is not limited to the illustrated examples, and appropriate modifications may be made within the scope of the spirit described above and below, and all such modifications are within the technical scope of the present invention. In the drawings, hatching and symbols may be omitted for convenience. In such cases, reference should be made to the specification and other drawings. Furthermore, the dimensions of various parts in the drawings may differ from the actual dimensions, as priority is given to helping understand the features of the present invention.

[0013] A cryoablation catheter according to one embodiment of the present invention is a cryoablation catheter having a longitudinal direction and a radial direction, and is characterized by having: a supply lumen extending in the longitudinal direction of the cryoablation catheter and allowing fluid to pass from the proximal side to the distal side; a balloon to which the fluid that has passed through the supply lumen is supplied; an exhaust flow path located in a region in the radial direction of the cryoablation catheter different from the supply lumen, extending in the longitudinal direction of the cryoablation catheter, and allowing the fluid that has passed inside the balloon to pass from the distal side to the proximal side; and a light-emitting unit located inside the balloon.

[0014] The overall configuration of a cryoablation catheter 100 according to an embodiment of the present invention will be described with reference to Figures 1 to 5. These figures show a cryoablation catheter 100 equipped with a supply lumen 31, a balloon 40, a discharge flow path 21, and a light-emitting unit 60. In these figures, the longitudinal direction of the cryoablation catheter 100 is indicated by x, the radial direction by y, and the circumferential direction by c.

[0015] Each of the members and parts of the cryoablation catheter 100 also has a longitudinal direction, a radial direction, and a circumferential direction. The longitudinal, radial, and circumferential directions of the members and parts of the cryoablation catheter 100 may or may not coincide with the longitudinal direction x, radial direction y, and circumferential direction c of the cryoablation catheter 100. For ease of understanding, this specification shows an embodiment in which the longitudinal, radial, and circumferential directions of all members and parts coincide with the longitudinal direction x, radial direction y, and circumferential direction c of the cryoablation catheter 100, respectively.

[0016] In this specification, the proximal side refers to the direction toward the user's hand relative to the longitudinal direction x of the cryoablation catheter 100, and the distal side refers to the opposite side of the proximal side, i.e., the direction toward the treatment target. Furthermore, when each component or part is divided into two equal parts along the longitudinal direction x of the cryoablation catheter 100, the distal part of each component or part is referred to as the distal part of each component or part, and the proximal part of each component or part is referred to as the proximal part of each component or part. The distal end of each component or part is the most distal end of each component or part. The proximal end of each component or part is the most proximal end of each component or part. The term "end" includes the peripheral portion of the end. That is, the distal end refers to the distal end and the peripheral portion of the distal end, and the proximal end refers to the proximal end and the peripheral portion of the proximal end.

[0017] Fig. 1 is a side view of a cryoablation catheter according to an embodiment of the present invention. Fig. 2 is a cross-sectional view of the distal portion of the cryoablation catheter shown in Fig. 1. Fig. 3 is a cross-sectional end view of the cryoablation catheter shown in Fig. 2 taken along line III-III. Fig. 4 is a cross-sectional view (partial side view) showing a modified example of the cryoablation catheter shown in Fig. 2. Fig. 5 is a cross-sectional end view of the cryoablation catheter shown in Fig. 4 taken along line VV.

[0018] 1, 2, and 4, the cryoablation catheter 100 has a longitudinal direction x and a radial direction y. As shown in FIGS. 2 to 5, the cryoablation catheter 100 has a supply lumen 31, a balloon 40, a discharge flow path 21, and a light-emitting unit 60.

[0019] As shown in FIGS. 2 to 5, the supply lumen 31 extends in the longitudinal direction x of the cryoablation catheter 100, and is a space through which a fluid can pass from the proximal side to the distal side.

[0020] The balloon 40 is supplied with fluid that has passed through the supply lumen 31. The balloon 40 has an interior 401 to which the fluid is supplied. The balloon 40 may have an inner surface 402 facing the interior 401 of the balloon 40 and an outer surface 403 facing the exterior of the balloon 40.

[0021] 1 to 5 show the balloon 40 in an expanded state. The balloon 40 is preferably configured to expand in diameter when a fluid is supplied to the interior 401 of the balloon 40, and to contract in diameter when the fluid is removed. When the balloon 40 is expanded in diameter, the outer surface 403 of the balloon 40 comes into contact with the wall of a biological tract, such as a blood vessel or the digestive tract, thereby stabilizing the position of the cryoablation catheter 100 within the body cavity. Furthermore, contact of the outer surface 403 of the balloon 40 with the wall of a biological tract, such as a blood vessel or the digestive tract, makes it easier to locally cool the tissue in contact with the outer surface 403 of the balloon 40.

[0022] 2 to 5, the discharge channel 21 is located in a different region from the supply lumen 31 in the radial direction y of the cryoablation catheter 100. The discharge channel 21 extends in the longitudinal direction x of the cryoablation catheter 100 and is a space through which the fluid that has passed through the interior 401 of the balloon 40 can pass from the distal side to the proximal side. The fluid that has been transported from the proximal side to the distal side of the cryoablation catheter 100 by passing through the supply lumen 31 is supplied to the balloon 40 and then discharged to the outside of the cryoablation catheter 100 via the discharge channel 21.

[0023] The light emitting portion 60 is a portion that emits light. The light emitting portion 60 is disposed inside the balloon 40.

[0024] The target tissue is cooled by the fluid passing through the supply lumen 31 and being transported to the balloon 40. After the cooling of the target tissue is complete, light is emitted from the light-emitting unit 60 disposed inside 401 of the balloon 40. This allows at least one of the balloon 40 and the tissue surrounding the balloon 40 to be warmed, making it easier to detach the balloon 40 from the target tissue. Therefore, after the cooling of the target tissue is complete, the balloon 40 can be easily removed without damaging the cooled tissue.

[0025] Cryoablation catheter 100 cools target tissue with fluid delivered by delivery lumen 31 .

[0026] The fluid is transported from the proximal side to the distal side of the cryoablation catheter 100 by passing through the supply lumen 31, and then from the distal side to the proximal side by passing through the discharge flow path 21, and is discharged outside the cryoablation catheter 100.

[0027] The fluid used in the cryoablation catheter 100 may be a liquid or a gas. When the fluid is a liquid, nitrogen or chlorofluorocarbon may be used as the fluid. When the fluid is a gas, argon, carbon dioxide, or nitrous oxide may be used as the fluid. From the viewpoint of being able to reduce pressure loss and energy loss, it is preferable that the fluid used in the cryoablation catheter 100 be a liquid.

[0028] As shown in FIGS. 1 to 5 , the cryoablation catheter 100 may have a light-emitting unit insertion lumen 37 into which a light-emitting unit 60 is inserted. Although not shown, a guidewire may be inserted into the light-emitting unit insertion lumen 37. In this case, the cryoablation catheter 100 can be used, for example, as follows. First, a guidewire is inserted into a body cavity, and then the balloon 40 is transported to the target tissue by inserting the guidewire into the light-emitting unit insertion lumen 37. Thereafter, the target tissue is cooled by flowing a fluid through the supply lumen 31 to supply the fluid to the interior 401 of the balloon 40. After the target tissue has been cooled, the guidewire is removed from the light-emitting unit insertion lumen 37, and the light-emitting unit 60 is inserted into the light-emitting unit insertion lumen 37 and transported to the interior 401 of the balloon 40. By emitting light from the light-emitting unit 60, at least one of the balloon 40 and the tissue surrounding the balloon 40 can be heated, which makes it easier to detach the balloon 40 from the target tissue. Therefore, after cooling of the target tissue is completed, the balloon 40 can be easily and smoothly removed while preventing damage to the cooled tissue.

[0029] Although not shown, the cryoablation catheter 100 may have a light-emitting unit insertion lumen 37 into which the light-emitting unit 60 is inserted and a guidewire lumen into which a guidewire is inserted. In this case, for example, the cryoablation catheter 100 can be used as follows. First, a guidewire is inserted into a body cavity, and then the balloon 40 is transported to the target tissue by inserting the guidewire into the guidewire lumen. Then, the target tissue is cooled by flowing a fluid through the supply lumen 31 to supply the fluid to the interior 401 of the balloon 40. After the target tissue has been cooled, the light-emitting unit 60 is inserted into the light-emitting unit insertion lumen 37 with the guidewire positioned in the guidewire lumen, and the light-emitting unit 60 is transported to the interior 401 of the balloon 40. By emitting light from the light-emitting unit 60, it is possible to heat at least one of the balloon 40 and the tissue surrounding the balloon 40, making it easier to detach the balloon 40 from the target tissue. Therefore, after cooling of the target tissue is completed, the balloon 40 can be easily and smoothly removed while preventing damage to the cooled tissue.

[0030] If there is no need to insert a guidewire, a guidewire need not be inserted into the light-emitting unit insertion lumen 37. The cryoablation catheter 100 may also not have a guidewire lumen. In this case, the catheter can be used, for example, as follows: First, the balloon 40 is inserted into a body cavity to transport the balloon 40 to the target tissue. Then, fluid is passed through the supply lumen 31 to supply the fluid to the interior 401 of the balloon 40, thereby cooling the target tissue. After the target tissue has been cooled, the light-emitting unit 60 is inserted into the light-emitting unit insertion lumen 37 and transported to the interior 401 of the balloon 40. By emitting light from the light-emitting unit 60, at least one of the balloon 40 and the tissue surrounding the balloon 40 can be heated, making it easier to detach the balloon 40 from the target tissue. Therefore, after cooling of the target tissue has been completed, the balloon 40 can be smoothly removed without damaging the cooled tissue.

[0031] 1 to 5, the cryoablation catheter 100 has a supply lumen 31, a balloon 40, an exhaust flow path 21, and a light-emitting unit 60. The supply lumen 31 and the exhaust flow path 21 may be included in a shaft 1 provided in the cryoablation catheter 100. In addition to the above, the shaft 1 may have a light-emitting unit insertion lumen 37 and a guidewire lumen. The shaft 1 preferably extends in the longitudinal direction x of the cryoablation catheter 100.

[0032] It is preferable that the light emitting unit 60 is movable inside the shaft 1 in the longitudinal direction x of the cryoablation catheter 100 .

[0033] An embodiment in which the light-emitting unit 60 cannot move in the longitudinal direction x of the cryoablation catheter 100 inside the shaft 1 is also acceptable. In this case, the light-emitting unit 60 may be fixed to the shaft 1. The light-emitting unit 60 may be embedded in the shaft 1. In such an embodiment, the light-emitting unit insertion lumen 37 does not need to be formed in the cryoablation catheter 100.

[0034] The shaft 1 may have a hollow cylindrical shape, a hollow polygonal prism shape, or the like.

[0035] The shaft 1 is preferably flexible because it is inserted into the body, allowing the shaft 1 to be deformed to fit the shape of the body cavity. In addition, the shaft 1 is preferably elastic so that it can maintain its shape.

[0036] Examples of the shaft 1 include a hollow body formed by arranging one or more wires in a predetermined pattern; a hollow body coated with a resin on at least one of the inner and outer surfaces; a resin tube; or a combination of these, such as a combination of these connected in the longitudinal direction. Examples of hollow bodies in which wires are arranged in a predetermined pattern include a tubular body having a mesh structure formed by crossing or weaving wires, and a coil formed by winding wires. The wires may be one or more solid wires or one or more twisted wires. The resin tube can be manufactured by, for example, extrusion molding. When the shaft 1 is a resin tube, it can be composed of a single layer or multiple layers. A portion of the shaft 1 in the longitudinal direction x or circumferential direction c of the cryoablation catheter 100 may be composed of a single layer, and the other portion may be composed of multiple layers.

[0037] The shaft 1 can be made of, for example, synthetic resins such as polyolefin resins (e.g., polyethylene and polypropylene), polyamide resins (e.g., nylon), polyester resins (e.g., PET), aromatic polyether ketone resins (e.g., PEEK), polyether polyamide resins, polyurethane resins, polyimide resins, and fluororesins (e.g., PTFE, PFA, and ETFE), or metals such as stainless steel, carbon steel, and nickel-titanium alloys. These may be used alone or in combination of two or more.

[0038] Although not shown, the shaft 1 may be integrally molded from a single member. For example, in a cross section perpendicular to the longitudinal direction x of the cryoablation catheter 100, the shaft 1 may be an integrally molded member having the supply lumen 31 and the discharge flow path 21 located in a different region from the supply lumen 31. In an embodiment in which the cryoablation catheter 100 has a light-emitting unit insertion lumen 37, the shaft 1 may be an integrally molded member having the supply lumen 31, the discharge flow path 21 located in a different region from the supply lumen 31, and the light-emitting unit insertion lumen 37 located in a different region from the supply lumen 31 and the discharge flow path 21 in a different region from the supply lumen 31 and the discharge flow path 21 in a cross section perpendicular to the longitudinal direction x of the cryoablation catheter 100. In an embodiment in which the cryoablation catheter 100 further has a guidewire lumen, in a cross section perpendicular to the longitudinal direction x of the cryoablation catheter 100, the shaft 1 may be an integrally molded member having a supply lumen 31, an exhaust flow path 21 located in a region different from the supply lumen 31, a light-emitting unit insertion lumen 37 located in a region different from the supply lumen 31 and the exhaust flow path 21, and a guidewire lumen located in a region different from the supply lumen 31, the exhaust flow path 21, and the light-emitting unit insertion lumen 37.

[0039] As shown in FIGS. 2 and 4 , the shaft 1 may be composed of multiple components. For example, the cryoablation catheter 100 may include, as the shaft 1, an outer shaft 20 having a lumen 20a extending in the longitudinal direction x of the cryoablation catheter 100, and an inner shaft 30 disposed in the lumen 20a of the outer shaft 20. The outer shaft 20 may have an inner surface 20b facing the lumen 20a and an outer surface 20c facing the exterior of the outer shaft 20. The inner shaft 30 may have a lumen 30a extending in the longitudinal direction x of the cryoablation catheter 100 and an outer surface 30c facing the exterior of the inner shaft 30. In the above case, the supply lumen 31 may be formed in the inner shaft 30. For example, the lumen 30a of the inner shaft 30 may be the supply lumen 31. The discharge flow path 21 may be a space existing between the outer surface 30c of the inner shaft 30 and the inner surface 20b of the outer shaft 20. In an embodiment in which the cryoablation catheter 100 has a light-emitting unit insertion lumen 37, the light-emitting unit insertion lumen 37 may be formed in the inner shaft 30. For example, the inner cavity 30a of the inner shaft 30 may be the light-emitting unit insertion lumen 37. In an embodiment in which the cryoablation catheter 100 has a separate guidewire lumen, the guidewire lumen may be formed in the inner shaft 30.

[0040] The outer shaft 20 and the inner shaft 30 may be made of the same material, or may be made of different materials.

[0041] As shown in FIGS. 2 and 3 , the inner shaft 30 may have a plurality of tubes each having a lumen 30a extending in the longitudinal direction x of the cryoablation catheter 100. More specifically, the inner shaft 30 may have a supply tube 35 each having a lumen 30a extending in the longitudinal direction x, and a light-emitting unit insertion tube 38 disposed in the lumen 30a of the supply tube 35. In this case, the supply lumen 31 may be the space between the outer surface of the light-emitting unit insertion tube 38 and the inner surface of the supply tube 35. The lumen 30a of the light-emitting unit insertion tube 38 may be the light-emitting unit insertion lumen 37. As shown in FIGS. 4 and 5 , the inner shaft 30 may have a plurality of tubes each having a lumen 30a extending in the longitudinal direction x of the cryoablation catheter 100, and the plurality of tubes may be aligned in the radial direction y of the cryoablation catheter 100. More specifically, the inner shaft 30 may have a plurality of tubes located in different regions in the radial direction y of the cryoablation catheter 100. In this case, one of the multiple tubes may be the supply tube 35, and the lumen 30a of the supply tube 35 may be the supply lumen 31. Another of the multiple tubes may be the light-emitting unit insertion tube 38, and the lumen 30a of the light-emitting unit insertion tube 38 may be the light-emitting unit insertion lumen 37. Although not shown, the inner shaft 30 may be a single tube, and this single tube may have a plurality of lumens 30a extending in the longitudinal direction x of the cryoablation catheter 100. In this case, one of the multiple lumens 30a may be the supply lumen 31, and another lumen 30a may be the light-emitting unit insertion lumen 37.

[0042] 2, the supply tube 35 may extend linearly in the longitudinal direction x of the cryoablation catheter 100. As shown in Fig. 4, the supply tube 35 may have a linear portion extending linearly in the longitudinal direction x of the cryoablation catheter 100 and a spiral portion located distal to the tubular portion and wound spirally.

[0043] 2, 4, and 5, the inner shaft 30 may have a hole 33 that connects the supply lumen 31 to the interior 401 of the balloon 40. The hole 33 is preferably located in the distal portion or distal end of the inner shaft 30.

[0044] 2 and 3, the holes 33 may be capable of injecting fluid toward the distal side of the cryoablation catheter 100. The fluid transported from the proximal side to the distal side by passing through the supply lumen 31 may be injected into the interior 401 of the balloon 40 via the holes 33 provided at the distal end of the supply tube 35 and transported to the discharge channel 21.

[0045] 4 and 5, the holes 33 may be capable of ejecting fluid outward in the radial direction y of the cryoablation catheter 100. The fluid transported from the proximal side to the distal side by passing through the supply lumen 31 is ejected into the interior 401 of the balloon 40 through the holes 33 formed in the side wall of the supply tube 35 and transported to the discharge flow path 21.

[0046] The cryoablation catheter 100 may have a light emitting member 61. The light emitting unit 60 may be a part of the light emitting member 61. For example, an optical fiber or an LED can be used as the light emitting member 61. When an optical fiber is used as the light emitting member 61, a clad-free portion, which will be described later, can be used as the light emitting unit 60. When an LED is used as the light emitting member 61, a light emitting element can be used as the light emitting unit 60. The light emitted from the light emitting unit 60 may flash. The light emitted from the light emitting unit 60 may be continuously lit. Note that FIGS. 2 to 5 show an embodiment in which an optical fiber is used as the light emitting member 61.

[0047] The optical fiber has a core and a cladding that covers the radially outer side of the core. It is preferable that the cladding is absent from a portion of the distal part of the core. The material that constitutes the core and the cladding is not particularly limited, but examples that can be used include glass such as silica glass and fluoride glass, and plastic.

[0048] The cladding-free portion refers to the portion of the optical fiber where no cladding exists radially outward from the core. By providing an optical fiber with a cladding-free portion, light can be emitted radially outward from the optical fiber.

[0049] In the longitudinal direction x of the cryoablation catheter 100, the location of the cladding-free portion is not particularly limited as long as it is a part of the distal portion of the core, but it is preferably located in a portion including the distal end of the core, which makes it easier to form the cladding-free portion.

[0050] The cladding-free areas can be formed by removing the cladding, for example, by etching or polishing. It is more preferable to roughen the outer surface of the cladding-free areas by sanding or other methods, which can improve the light diffusion properties of the cladding-free areas.

[0051] The light emitting section 60 may be a member having light diffusibility that is provided separately from the optical fiber.

[0052] The light-emitting unit 60 is preferably connected to a power supply device or a light source device. A power supply device refers to a device that supplies electricity to the light-emitting unit 60, and a light source device refers to a device that supplies light to the light-emitting unit 60. Examples of light source devices that can be used include an LED light source device and a halogen light source device. Here, "the light-emitting unit 60 is connected to a power supply device or a light source device" does not necessarily mean that the light-emitting unit 60 and the power supply device or the light source device are directly connected. For example, this also includes a configuration in which the light-emitting unit 60 and the power supply device are connected via a conductor or the like, or a configuration in which the light-emitting unit 60 and the light source device are indirectly connected via an optical fiber or the like.

[0053] The light emitted from the light-emitting unit 60 preferably includes light with a wavelength of 600 nm or more and 2500 nm or less. The light-emitting unit 60 may temporarily emit light with a wavelength less than 600 nm. The light-emitting unit 60 may also temporarily emit light with a wavelength greater than 2500 nm. When the light emitted from the light-emitting unit 60 includes light with a wavelength of 600 nm or more and 2500 nm or less, the tissue surrounding the balloon 40 can be easily heated, making it easier to detach the balloon 40 from the target tissue. This makes it easier to smoothly remove the balloon 40 after cooling of the target tissue has been completed, while preventing damage to the cooled tissue. To enhance this effect, the light emitted from the light-emitting unit 60 may only include light with a wavelength of 600 nm or more and 2500 nm or less.

[0054] Examples of materials that can be used to form the balloon 40 include polyamide resins such as nylon 11 and nylon 12, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polyurethane resins, thermoplastic elastomers such as polyether block amide copolymers, and combinations of these.

[0055] As shown in FIGS. 4 and 5 , the holes 33 are preferably located inside 401 of the balloon 40. For example, the holes 33 are preferably formed in a portion of the inner shaft 30 that is located inside 401 of the balloon 40. The holes 33 may also be formed in a portion of the inner shaft 30 that is not located inside 401 of the balloon 40; however, the holes 33 are preferably formed only in a portion of the inner shaft 30 that is located inside 401 of the balloon 40. This makes it easier to increase the distance between the holes 33 and portions other than the balloon 40, thereby making it easier to reduce the cooling efficiency in portions other than the balloon 40. This makes it easier to increase the freezing efficiency of the tissue where the balloon 40 is located.

[0056] The balloon 40 preferably has a first portion 40a and a second portion 40b having a higher absorption rate of light emitted by the specific light-emitting element than the first portion 40a. In this specification, the specific light-emitting element is assumed to be an infrared LED, L12170, manufactured by Hamamatsu Photonics K.K. By using a balloon 40 having a second portion 40b with a high absorption rate of infrared light such as that emitted by the specific light-emitting element, the second portion 40b is more likely to warm up, making it easier to peel off from the target tissue. This allows the balloon 40 to be easily removed after cooling of the target tissue has been completed without damaging the cooled tissue.

[0057] 2 and 4, when the balloon 40 is in an expanded diameter state, the balloon 40 may have a cylindrical straight tube portion 41, a distal tapered portion 42 located distal to the straight tube portion 41 and having an outer diameter that decreases distally, and a proximal tapered portion 43 located proximal to the straight tube portion 41 and having an outer diameter that decreases proximally. Furthermore, the balloon 40 may have a distal sleeve portion 44 located distal to the distal tapered portion 42 and fixed to the outer surface 30c of the inner shaft 30, and a proximal sleeve portion 45 located proximal to the proximal tapered portion 43 and fixed to the outer surface 20c of the outer shaft 20.

[0058] 2 and 4, the second portion 40b is preferably located in the straight tube portion 41. By positioning the second portion 40b, which has a high absorption rate of infrared light such as that emitted by a specific light-emitting member, in the straight tube portion 41, the straight tube portion 41 is more likely to heat up, making it easier to peel off the straight tube portion 41 from the target tissue. This makes it easier to smoothly remove the balloon 40 after cooling of the target tissue is complete, while preventing damage to the cooled tissue.

[0059] As shown in FIGS. 2 to 5, the balloon 40 may have an outer balloon 46 and an inner balloon 47 disposed inside the outer balloon 46.

[0060] The outer balloon 46 and the inner balloon 47 may be made of the same material, or may be made of different materials.

[0061] As shown in FIGS. 2 to 5 , the balloon 40 may have a first layer 48 disposed between the outer balloon 46 and the inner balloon 47. The first layer 48 preferably has a higher absorptance of light emitted by the specific light-emitting member than the outer balloon 46 and the inner balloon 47. Having a first layer 48 with a high absorptance of infrared light such as that emitted by the specific light-emitting member makes it easier to heat the outer balloon 46 and the inner balloon 47 via the easily warmable first layer 48, thereby also making it easier to heat the tissue surrounding the balloon 40. This allows the balloon 40 to be smoothly removed after cooling of the target tissue has been completed, without damaging the cooled tissue.

[0062] Examples of materials constituting the first layer 48 include infrared-absorbing substances such as graphite, tin-doped indium oxide, antimony-doped tin oxide, lanthanum hexaboride, cesium-doped tungsten oxide, and phthalocyanine compounds. For example, the entire first layer 48 may be made of the above-mentioned infrared-absorbing substances. The above-mentioned infrared-absorbing substances may be included as part of the materials constituting the first layer 48. In this case, the first layer 48 may be formed by dispersing the above-mentioned infrared-absorbing substances in the materials listed as possible materials for constituting the balloon 40.

[0063] The balloon 40 is disposed between the outer balloon 46 and the inner balloon 47, and preferably has a second layer 49 that is radiopaque, which allows the position of the balloon 40 and the expanded state of the balloon 40 to be visually confirmed under X-ray fluoroscopy.

[0064] The second layer 49 can be made of a radiopaque material such as lead, barium, iodine, tungsten, tantalum, gold, platinum, iridium, stainless steel, titanium, or a cobalt-chromium alloy. For example, the entire second layer 49 may be made of the radiopaque material. The radiopaque material may be included as part of the material that makes up the second layer 49. In this case, the second layer 49 may be made by dispersing the radiopaque particles in a material that can be used to make the balloon 40.

[0065] As shown in FIGS. 2 to 5, the second layer 49 is preferably located closer to the outer balloon 46 than the first layer 48. The first layer 48 is preferably located closer to the inner balloon 47 than the second layer 49. This allows the first layer 48 to be more easily exposed to light emitted by the light-emitting unit 60, making it easier to heat the first layer 48 and also to heat the outer balloon 46 and inner balloon 47 via the first layer 48. This makes it easier to heat the tissue surrounding the balloon 40. This allows the balloon 40 to be smoothly removed after cooling of the target tissue has been completed, while preventing damage to the cooled tissue.

[0066] The first layer 48 and the second layer 49 are preferably located in the straight tube portion 41. By having the first layer 48 located in the straight tube portion 41, the straight tube portion 41 is more likely to warm up, making it easier to peel off from the target tissue. This makes it easier to smoothly remove the balloon 40 after cooling of the target tissue is complete, while preventing damage to the cooled tissue. Furthermore, by having the second layer 49 located in the straight tube portion 41, the position of the straight tube portion 41 and the expanded state of the straight tube portion 41 can be visually confirmed under X-ray fluoroscopy.

[0067] As shown in Figures 1, 2, and 4, the cryoablation catheter 100 may further include a distal tip 50 having a lumen 51 extending in the longitudinal direction x of the cryoablation catheter 100 and an outer diameter that decreases from the proximal end to the distal end. The distal tip 50 is preferably connected to the distal end of the shaft 1. In an embodiment in which the cryoablation catheter 100 has a light-emitting unit insertion lumen 37 or a guidewire lumen, the distal tip 50 and the shaft 1 are preferably connected so that the light-emitting unit insertion lumen 37 or the guidewire lumen communicates with the lumen 51 of the distal tip 50. By including a distal tip 50 whose outer diameter decreases from the proximal side to the distal side, the distal end of the cryoablation catheter 100 can be more easily inserted into a body cavity. Although not shown, in cases where a guidewire is not required or where the light-emitting unit 60 is fixed to the shaft 1, it is not necessary for the distal tip 50 to have an inner cavity 51 communicating with the light-emitting unit insertion lumen 37 or the guidewire lumen, and therefore the distal tip 50 of the cryoablation catheter 100 does not need to have an inner cavity 51. In other words, the distal tip 50 may have a solid structure.

[0068] The shape of the distal tip 50 can be, for example, a hollow cone, a hollow polygonal pyramid, a hollow truncated cone, a hollow truncated polygonal pyramid, a hemisphere with an internal cavity, a cone, a polygonal pyramid, a truncated cone, a polygonal pyramid, a hemisphere, etc.

[0069] The material constituting the distal tip 50 can be any of the materials exemplified as materials constituting the shaft 1. The material constituting the distal tip 50 and the material constituting the shaft 1 may be the same or different.

[0070] As shown in FIG. 1 , a hub 2 may be connected to the proximal portion of the shaft 1. The shaft 1 and the hub 2 may be fixed together. For example, the shaft 1 and the hub 2 can be fixed together by adhesive bonding, welding, screws, or the like. Among these, it is preferable that the shaft 1 and the hub 2 are fixed together by adhesive bonding. Fixing the shaft 1 and the hub 2 together by adhesive bonding can increase the strength of the connection between the shaft 1 and the hub 2 when the shaft 1 and the hub 2 are made of different materials, for example, when the shaft 1 is made of a highly flexible material and the hub 2 is made of a highly rigid material, thereby making it easier to improve the durability of the cryoablation catheter 100.

[0071] The hub 2 may be provided with a fluid injection section 3 capable of injecting a fluid passing through a supply lumen 31 from the proximal side to the distal side. The fluid injection section 3 may be connected to a fluid supply device 4. Examples of the fluid supply device 4 include a regulator, a flow rate controller, and a pump connected to a container in which the fluid is stored.

[0072] FIG. 1 discloses an embodiment in which a guidewire port 5 is formed midway from the distal end to the proximal end of the shaft 1. The guidewire port 5 is in communication with the light-emitting unit insertion lumen 37 or the guidewire lumen of the shaft 1. FIG. 1 shows a so-called rapid exchange type cryoablation catheter 100. The shaft 1 may have a distal shaft portion 1a and a proximal shaft portion 1b located proximal to the distal shaft portion 1a. The distal shaft portion 1a and the proximal shaft portion 1b may be separate members, with the proximal end of the member constituting the distal shaft portion 1a connected to the distal end of the member constituting the proximal shaft portion 1b. Alternatively, the distal shaft portion 1a and the proximal shaft portion 1b may be formed from a single member.

[0073] Although not shown, the cryoablation catheter 100 may also be of a so-called over-the-wire type, in which the light-emitting unit insertion lumen 37 or the guidewire lumen is formed from the distal end to the proximal end of the shaft 1. When the cryoablation catheter 100 is of the over-the-wire type, it is preferable that the light-emitting unit insertion lumen 37 or the guidewire lumen extend to the position where the hub 2 is located in the longitudinal direction x of the cryoablation catheter 100.

[0074] Regardless of whether the cryoablation catheter 100 is a rapid exchange type or an over-the-wire type, the supply lumen 31 and the discharge channel 21 preferably extend in the longitudinal direction x of the cryoablation catheter 100 to the position where the hub 2 is located.

[0075] The outer surface of the shaft 1 and the outer surface of the distal tip 50 may be coated. As shown in FIG. 1, when the cryoablation catheter 100 is a rapid exchange type, the outer surface of at least one of the distal shaft portion 1a and the proximal shaft portion 1b may be coated, or the outer surfaces of both the distal shaft portion 1a and the proximal shaft portion 1b may be coated. When the cryoablation catheter 100 is an over-the-wire type, only a portion or the entire outer surface of the shaft 1 may be coated. Only a portion or the entire outer surface of the distal tip 50 may be coated.

[0076] The coating applied to the outer surface of the shaft 1 or the outer surface of the distal tip 50 can be a hydrophilic coating or a hydrophobic coating depending on the purpose. The coating can be applied by immersing the shaft 1 or the distal tip 50 in a hydrophilic or hydrophobic coating agent, by applying a hydrophilic or hydrophobic coating agent to the outer surface of the shaft 1 or the outer surface of the distal tip 50, or by covering the outer surface of the shaft 1 or the outer surface of the distal tip 50 with a hydrophilic or hydrophobic coating agent. Drugs or additives may be added to the coating agent.

[0077] Examples of hydrophilic coating agents include hydrophilic polymers such as polyvinyl alcohol, polyethylene glycol, polyacrylamide, polyvinylpyrrolidone, and methyl vinyl ether-maleic anhydride copolymer, and hydrophilic coating agents composed of combinations of these.

[0078] Examples of hydrophobic coating agents include polytetrafluoroethylene (PTFE), fluorinated ethylene propylene (FEP), perfluoroalkoxyalkane (PFA), silicone oil, hydrophobic urethane resin, carbon coating, diamond coating, diamond-like carbon (DLC) coating, ceramic coating, and substances with low surface free energy terminated with alkyl groups or perfluoroalkyl groups.

[0079] In the longitudinal direction x of the cryoablation catheter 100, the length of the cryoablation catheter 100 can be 80 cm or more, 100 cm or more, 120 cm or more, etc. In the longitudinal direction x of the cryoablation catheter 100, the length of the cryoablation catheter 100 can be 250 cm or less, 230 cm or less, 210 cm or less, etc.

[0080] In the radial direction y of the cryoablation catheter 100, the length of the cryoablation catheter 100 can be 1.0 mm or more, 2.0 mm or more, 3.0 mm or more, etc. In the radial direction y of the cryoablation catheter 100, the length of the cryoablation catheter 100 can be 6.0 mm or less, 5.0 mm or less, 4.0 mm or less, etc. [Explanation of symbols]

[0081] 1: Shaft 1a: Distal shaft part 1b: Proximal shaft 2: Hub 3:Fluid injection part 4: Fluid supply device 5: Guidewire port 20: Outer shaft 20a: lumen 20b: Inner surface 20c: Outer surface 21: Discharge flow path 30: Inner shaft 30a: lumen 30c: Outer surface 31: Supply lumens 33: Hole 35: Supply tube 37: Lumens inserted into the light-emitting section 38: Light emitting part insertion tube 40: Balloon 40a: 1st part 40b:Second part 41: Straight pipe section 42: Distal tapered section 43: Proximal tapered section 44: Distal sleeve 45: Proximal sleeve part 46: Outer Balloon 47: Inner balloon 48: 1st layer 49:Second layer 401: Internal 402:Inner surface 403:Outer surface 50: Tip 51: lumen 60: Light emitting part 61: Light emitting member 100: Cryoablation catheter

Claims

1. 1. A cryoablation catheter having a longitudinal direction and a radial direction, a supply lumen extending in the longitudinal direction and allowing fluid to pass from the proximal side to the distal side; a balloon to which the fluid that has passed through the supply lumen is supplied; a discharge flow path that is located in a region different from the supply lumen in the radial direction, extends in the longitudinal direction, and allows a fluid that has passed through the interior of the balloon to pass from the distal side to the proximal side; a light emitting unit disposed inside the balloon; A cryoablation catheter having:

2. 2. The cryoablation catheter according to claim 1, wherein the light emitted from the light emitting portion includes light having a wavelength of 600 nm or more and 2500 nm or less.

3. 3. The cryoablation catheter according to claim 1, wherein the balloon has a first portion and a second portion having a higher absorption rate of light emitted by the specific light-emitting member than the first portion.

4. the balloon has a straight tube portion, a distal tapered portion located distal to the straight tube portion and having an outer diameter that decreases toward the distal side, and a proximal tapered portion located proximal to the straight tube portion and having an outer diameter that decreases toward the proximal side; The cryoablation catheter according to claim 3 , wherein the second portion is located in the straight tube portion.

5. 3. The cryoablation catheter according to claim 1, wherein the balloon comprises an outer balloon and an inner balloon disposed inside the outer balloon.

6. the balloon has a first layer disposed between the outer balloon and the inner balloon; 6. The cryoablation catheter of claim 5, wherein the absorption rate of light emitted by the specific light-emitting element in the first layer is greater than the absorption rate of light emitted by the specific light-emitting element in the outer balloon and the absorption rate of light emitted by the specific light-emitting element in the inner balloon.

7. 7. The cryoablation catheter according to claim 6, wherein the balloon is disposed between the outer balloon and the inner balloon and has a second layer that is radiopaque.

8. The cryoablation catheter according to claim 7 , wherein the second layer is located closer to the outer balloon than the first layer.

9. the balloon has a straight tube portion, a distal tapered portion located distal to the straight tube portion and having an outer diameter that decreases toward the distal side, and a proximal tapered portion located proximal to the straight tube portion and having an outer diameter that decreases toward the proximal side; The cryoablation catheter according to claim 7 , wherein the first layer and the second layer are located in the straight tube portion.

10. The cryoablation catheter includes an outer shaft having a lumen extending in the longitudinal direction, and an inner shaft disposed in the lumen of the outer shaft, the supply lumen is formed in the inner shaft; 3. The cryoablation catheter according to claim 1, wherein the discharge flow path is a space existing between an outer surface of the inner shaft and an inner surface of the outer shaft.

11. 11. The cryoablation catheter of claim 10, wherein the inner shaft has a hole communicating the supply lumen with the interior of the balloon.

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