Cryoablation catheter

Abstract

This cryoablation catheter (100) has an outer cylinder (30), a balloon (60), a guide wire tube (10), a gas supply tube (20) having a spiral part (22) wound around the guide wire tube (10), and a gas discharge lumen (3) present between the outer cylinder (30) and the guide wire tube (10) and the gas supply tube (20). The cryoablation catheter (100) has a large-diameter section (101) that extends in the longitudinal direction (x) of the outer cylinder (30), the lumen (22e) of the spiral part (22) located farther inward in the radial direction of the guide wire tube (10) than the inner surface (22c) of the spiral part (22) having a diameter greater than the outer diameter of the guide wire tube (10).

Description

Cryoablation Catheter

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

[0002] Cryoablation is a medical technique that freezes and necroses cells constituting a target tissue by bringing a cryo-cooled device into contact with the target tissue, and is used in the treatment of myocardial tissue and tumor tissue. Methods for cooling the device include those using liquid nitrogen and those using the Joule-Thomson effect with high-pressure gas.

[0003] For example, Patent Document 1 describes a cryosurgical catheter comprising a catheter body having a proximal end portion, a distal end portion, and a main lumen penetrating therethrough. A balloon for containing cryofluid supplied through the main lumen is placed on the orifice of the catheter body constituting the cryosurgical catheter. The cryofluid is supplied to the balloon through the catheter body, which inflates the balloon and cools the affected area. More specifically, it discloses an embodiment in which cryofluid conveyed from the proximal side to the distal side via a cryofluid supply tube is supplied into the balloon through a port formed in a diffuser, and the cryofluid is discharged through a discharge lumen.

[0004] Japanese National Publication of International Patent Application No. 2001-524345

[0005] To improve the cooling efficiency of the cryosurgical catheter described in Patent Document 1, for example, it is conceivable to increase the flow rate of cryofluid that can be supplied within a certain period of time. However, this approach requires increasing the volume of the main lumen for supplying the cryofluid, which results in an increase in the outer diameter of the cryosurgical catheter. Nevertheless, in consideration of insertability through a body cavity, there has been a demand for a cryosurgical catheter that can easily improve cooling efficiency without increasing the outer diameter.

[0006] The present invention has been made in view of the foregoing circumstances, and an object thereof is to provide a cryoablation catheter that can easily improve cooling efficiency without increasing the outer diameter.

[0007] A cryoablation catheter according to an embodiment of the present invention that has solved the above problems is as follows: [1] A cryoablation catheter comprising: an outer cylinder; a balloon provided at the distal end of the outer cylinder; a guidewire tube disposed in the lumen of the outer cylinder and inside the balloon; a gas supply tube disposed in the lumen of the outer cylinder and inside the balloon, having a helical portion wound around the guidewire tube, and having injection holes in the helical portion for injecting gas toward the inside of the balloon; and a gas discharge lumen located between the outer cylinder, the guidewire tube and the gas supply tube, wherein the helical portion has an inner surface which is the outer surface of the gas supply tube and is located on the guidewire tube side, and has a large-diameter section in which the lumen of the helical portion, located radially inward of the guidewire tube from the inner surface of the helical portion, has a diameter larger than the outer diameter of the guidewire tube.

[0008] Because the cryoablation catheter described above has a large-diameter section, the injection holes located in the helical section can approach the inner surface of the balloon, making it easier for the low-temperature gas to reach the inner surface of the balloon while maintaining its temperature. This makes it easier to improve cooling efficiency without increasing the outer diameter of the cryoablation catheter.

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

[10] . [2] The cryoablation catheter according to [1], wherein at least one of the distal end and the proximal end of the helical portion is fixed to the guidewire tube. [3] The cryoablation catheter according to [1] or [2], wherein the midpoint of the helical portion in the longitudinal direction of the outer cylinder is not in contact with the guidewire tube. [4] The cryoablation catheter according to any one of [1] to [3], wherein there is a separation section in the longitudinal direction of the outer cylinder, in which the guidewire tube and the helical portion are separated in the radial direction of the outer cylinder. [5] The cryoablation catheter according to [4], wherein there is a gap between the guidewire tube and the helical portion in the separation section. [6] A cryoablation catheter according to any one of [1] to [5], having: a contact section which is a section extending in the longitudinal direction of the outer cylinder in which the guide wire tube and the helical portion are in contact; and a non-contact section which is a section extending in the longitudinal direction of the outer cylinder in which the guide wire tube and the helical portion are not in contact. [7] A cryoablation catheter according to [6], wherein the length of the non-contact section in the longitudinal direction of the outer cylinder is longer than the length of the contact section in the longitudinal direction of the outer cylinder. [8] A cryoablation catheter according to [7], wherein the length of the non-contact section in the longitudinal direction of the outer cylinder is twice or more the length of the contact section in the longitudinal direction of the outer cylinder. [9] The cryoablation catheter according to [1], wherein the gas supply tube has a linear portion extending in the longitudinal direction of the outer cylinder proximal to the helical portion, the linear portion being fixed to the guide wire tube, and the helical portion not being fixed to the guide wire tube.

[10] The cryoablation catheter according to [2], wherein the gas supply tube has a linear portion extending in the longitudinal direction of the outer cylinder proximal to the helical portion, and the linear portion is not fixed to the guide wire tube.

[0010] Because the cryoablation catheter described above has a large-diameter section, the injection holes located in the helical section can approach the inner surface of the balloon, making it easier for the low-temperature gas to reach the inner surface of the balloon while maintaining its temperature. This makes it easier to improve cooling efficiency without increasing the outer diameter of the cryoablation catheter.

[0011] Figure 1 shows a side view of a cryoablation catheter according to an embodiment of the present invention. Figure 2 shows a cross-sectional view (partial side view) of the cryoablation catheter shown in Figure 1. Figure 3 shows a cross-sectional view (partial side view) of a modified example of the cryoablation catheter shown in Figure 2. Figure 4 shows a cross-sectional view (partial side view) of a modified example of the cryoablation catheter shown in Figure 2.

[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 it is possible to implement it with appropriate modifications within the scope that is consistent with the spirit described above and below, and all such modifications are included within the technical scope of the present invention. In each drawing, hatching and reference numerals may be omitted for convenience, in which case refer to the specification or other drawings. Also, the dimensions of various parts in the drawings may differ from the actual dimensions, as priority is given to helping to understand the features of the present invention.

[0013] A cryoablation catheter according to one embodiment of the present invention comprises an outer canister, a balloon provided at the distal end of the outer canister, a guidewire tube disposed within the lumen of the outer canister and inside the balloon, a gas supply tube disposed within the lumen of the outer canister and inside the balloon, having a helical portion wound around the guidewire tube and having injection holes in the helical portion for injecting gas toward the inside of the balloon, and a gas discharge lumen located between the outer canister, the guidewire tube and the gas supply tube, wherein the helical portion has an inner surface which is the outer surface of the gas supply tube and is located on the guidewire tube side, and in a section extending in the longitudinal direction of the outer canister, there is a large-diameter section in which the lumen of the helical portion located radially inward from the inner surface of the helical portion has a larger diameter than the outer diameter of the guidewire tube.

[0014] Referring to Figures 1 to 4, the overall configuration of a cryoablation catheter according to an embodiment of the present invention will be described. Figures 1 to 4 show a cryoablation catheter 100 comprising an outer cylinder 30, a balloon 60, a guide wire tube 10, a gas supply tube 20, and a gas discharge lumen 3.

[0015] In this drawing, the longitudinal direction of the outer cylinder 30 is indicated by x, and the radial direction of the outer cylinder 30 is indicated by y. The radial direction y is perpendicular to the longitudinal direction x. In other words, the longitudinal direction x of the outer cylinder 30 can also be said to be the direction of extension of the outer cylinder 30.

[0016] In this specification, the proximal side refers to the direction toward the user's hand relative to the longitudinal direction x of the outer cylinder 30, and the distal side refers to the opposite side of the proximal side, i.e., the direction toward the treatment target. Furthermore, when each member or part is divided into two equal parts along the longitudinal direction x of the outer cylinder 30, the part located on the distal side of each member or part is called the distal part, and the part located on the proximal side of each member or part is called the proximal part. The distal end of each member or part is the end located furthest distally from each member or part. The proximal end of each member or part is the end located furthest proximal from each member or part. The end of each member or part refers to the part including the end of each member or part and its surroundings. That is, the distal end of each member or part refers to the part including the distal end of each member or part and its surroundings, and the proximal end of each member or part refers to the part including the proximal end of each member or part and its surroundings.

[0017] As shown in Figures 1 to 4, the cryoablation catheter 100 comprises an outer tube 30, a balloon 60, a guidewire tube 10, a gas supply tube 20, and a gas discharge lumen 3.

[0018] The outer cylinder 30 has a longitudinal direction x, a radial direction y, and a circumferential direction, and preferably has an inner lumen 30e extending in the longitudinal direction x.

[0019] The balloon 60 is provided at the distal end of the outer cylinder 30. Preferably, the balloon 60 expands when gas is supplied and deflates when the gas is removed.

[0020] The guidewire tube 10 is positioned inside the lumen 30e of the outer cylinder 30 and the balloon 60. Preferably, the guidewire tube 10 extends in the longitudinal direction x of the outer cylinder 30. It is also preferable that the guidewire tube 10 has a lumen 10e that extends in the longitudinal direction x of the outer cylinder 30. Preferably, the lumen 10e of the guidewire tube 10 functions as a guidewire lumen 1, i.e., a space through which the guidewire is inserted.

[0021] The gas supply tube 20 is located inside the lumen 30e of the outer cylinder 30 and the balloon 60. Preferably, the gas supply tube 20 extends in the longitudinal direction x of the outer cylinder 30. Preferably, the gas supply tube 20 has a lumen 20e that extends in the longitudinal direction of the gas supply tube 20. Preferably, the lumen 20e of the gas supply tube 20 functions as a gas supply lumen 2, that is, a space through which gas can pass from the proximal side to the distal side.

[0022] The gas supply tube 20 preferably has an inner surface 20c and an outer surface 20d. The inner surface 20c of the gas supply tube 20 is preferably a surface that partitions its inner lumen 20e.

[0023] The gas supply tube 20 has a helical portion 22 that is wound around the guide wire tube 10. The helical portion 22 of the gas supply tube 20 is also provided with injection holes 4 that inject gas into the inside of the balloon 60. Preferably, the injection holes 4 are located inside the balloon 60.

[0024] The helical portion 22 has an inner surface 22c which is the outer surface 20d of the gas supply tube 20 and is located on the side facing the guide wire tube 10. Alternatively, the helical portion 22 may also have an outer surface 22d which is the outer surface 20d of the gas supply tube 20 and is located on the side opposite to the guide wire tube 10.

[0025] The gas discharge lumen 3 is the space located between the outer cylinder 30, the guidewire tube 10, and the gas supply tube 20. In other words, the gas discharge lumen 3 can be described as the space within the lumen 30e of the outer cylinder 30, excluding the space occupied by the guidewire tube 10 and the gas supply tube 20. It is preferable that the gas discharge lumen 3 extends in the longitudinal direction x of the outer cylinder 30. It is preferable that the gas discharge lumen 3 is a space through which the gas injected from the injection hole 4 can pass from the distal side to the proximal side. It is preferable that the gas, transported from the proximal side to the distal side of the outer cylinder 30 by passing through the gas supply lumen 2, is supplied to the inside of the balloon 60 and then discharged to the outside of the cryoablation catheter 100 via the gas discharge lumen 3.

[0026] The cryoablation catheter 100 has a large-diameter section 101 in which the lumen 22e of the helical portion 22, which is located radially inward of the guidewire tube 10 beyond the inner surface 22c of the helical portion 22, has a larger diameter than the outer diameter of the guidewire tube 10.

[0027] The diameter of the lumen 22e of the helical portion 22 and the outer diameter of the guide wire tube 10 are measured in a cross section perpendicular to the longitudinal direction x of the outer cylinder 30. If the outer shape of the lumen 22e of the helical portion 22 in a cross section perpendicular to the longitudinal direction x of the outer cylinder 30 is not a perfect circle, the diameter of the lumen 22e of the helical portion 22 is defined as the average of the diameter of the circle circumscribing the outer shape of the lumen 22e of the helical portion 22 in a cross section perpendicular to the longitudinal direction x of the outer cylinder 30 and the diameter of the circle inscribed in the outer shape of the lumen 22e of the helical portion 22 in a cross section perpendicular to the longitudinal direction x of the outer cylinder 30. Furthermore, if the outer shape of the guide wire tube 10 in a cross section perpendicular to the longitudinal direction x of the outer cylinder 30 is not a perfect circle, the outer diameter of the guide wire tube 10 is defined as the average of the diameter of the circle circumscribing the outer shape of the guide wire tube 10 in a cross section perpendicular to the longitudinal direction x of the outer cylinder 30 and the diameter of the circle inscribed in the outer shape of the guide wire tube 10 in a cross section perpendicular to the longitudinal direction x of the outer cylinder 30.

[0028] Because the cryoablation catheter 100 has a large-diameter section 101, the injection holes 4 provided in the helical section 22 can approach the inner surface of the balloon 60, making it easier for the low-temperature gas to reach the inner surface of the balloon 60 while maintaining its temperature. This makes it easier to improve cooling efficiency without increasing the outer diameter of the cryoablation catheter 100.

[0029] The cryoablation catheter 100 freezes and necrotizes the cells that make up the target tissue by coming into contact with it.

[0030] Since the outer cylinder 30 is inserted into the body, it is preferably flexible. This allows the outer cylinder 30 to be deformed to conform to the shape of the body cavity. Furthermore, it is preferable that the outer cylinder 30 has elasticity to maintain its shape.

[0031] The outer cylinder 30 can be, for example, a hollow body formed by arranging one or more wires in a predetermined pattern; a hollow body with at least one of its inner or outer surfaces coated with resin; a resin tube; or a combination thereof, for example, one in which these are connected in the longitudinal direction x. Examples of hollow bodies in which wires are arranged in a predetermined pattern include cylindrical bodies having a mesh structure due to the intersecting or weaving of wires, and coils in which wires are wound. The wires may be one or more single wires, or one or more stranded wires. The resin tube can be manufactured, for example, by extrusion molding. When the outer cylinder 30 is a resin tube, the outer cylinder 30 can be composed of a single layer or multiple layers. The outer cylinder 30 may be composed of a single layer in part of its longitudinal direction x or circumferential direction, and the other part may be composed of multiple layers.

[0032] The outer cylinder 30 can be made of synthetic resins such as polyolefin resin (e.g., polyethylene or polypropylene), polyamide resin (e.g., nylon), polyester resin (e.g., PET), aromatic polyetherketone resin (e.g., PEEK), polyetherpolyamide resin, polyurethane resin, polyimide resin, or fluororesin (e.g., PTFE, PFA, ETFE), or metals such as stainless steel, carbon steel, or nickel-titanium alloy. These can be used individually or in combination of two or more.

[0033] Since the guidewire tube 10 is inserted into the body, it is preferably flexible. This allows the guidewire tube 10 to deform to conform to the shape of the body cavity. Furthermore, to maintain its shape, it is preferable that the guidewire tube 10 is elastic.

[0034] The materials that can be used to construct the guide wire tube 10 are those listed as materials that can be used to construct the outer cylinder 30.

[0035] Since the gas supply tube 20 is inserted into the body, it is preferably flexible. This allows the gas supply tube 20 to deform to conform to the shape of the body cavity. Furthermore, to maintain its shape, it is preferable that the gas supply tube 20 is elastic.

[0036] The materials that can be used to construct the gas supply tube 20 are those listed as materials that can be used to construct the outer cylinder 30.

[0037] The outer cylinder 30, gas supply tube 20, and guide wire tube 10 may be made of the same material, or they may be made of different materials.

[0038] Multiple injection holes 4 may be provided in the gas supply tube 20, or only one may be provided in the gas supply tube 20.

[0039] The shape of the injection port 4 is not particularly limited, but it can be circular, elliptical, polygonal, or the like.

[0040] The balloon 60 is preferably made of a resin. Examples of the resin constituting the balloon 60 include polyamide resin, polyester resin, polyurethane resin, polyolefin resin, vinyl chloride resin, silicone resin, and natural rubber. Only one of these may be used alone, or two or more thereof may be used in combination. Among these, polyamide resins, polyester resins, and polyurethane resins are preferably used. An elastomer resin can be used from the viewpoint of reducing the thickness and improving the flexibility of the balloon 60.

[0041] The balloon 60 may comprise an expandable / contractible portion 62 that can be expanded and contracted, a distal sleeve portion 61 that is located on the distal side relative to the expandable / contractible portion 62 and is fixed to the guide wire tube 10, and a proximal sleeve portion 63 that is located on the proximal side relative to the expandable / contractible portion 62 and is fixed to the outer cylinder 30.

[0042] As shown in FIGS. 1 to 4, the cryoablation catheter 100 may have a hub 90.

[0043] FIGS. 2 to 4 disclose an embodiment in which a guide wire port 52 for inserting a guide wire into the interior of the cryoablation catheter 100 is formed between the balloon 60 and the hub 90. FIGS. 2 to 4 show a so-called rapid exchange type cryoablation catheter 100. Although not shown in the figures, the cryoablation catheter 100 may be a so-called over-the-wire type cryoablation catheter in which the guide wire lumen 1 extends to the hub 90.

[0044] The cryoablation catheter 100 may have only one large-diameter section 101, or may have a plurality of large-diameter sections 101.

[0045] In the longitudinal direction x of the outer cylinder 30, the position of the distal end of the large-diameter section 101 may be located at the same position as the distal end 22a of the helical portion 22. The distal end of the large-diameter section 101 may be located closer to the proximal side than the distal end 22a of the helical portion 22. In the longitudinal direction x of the outer cylinder 30, the position of the proximal end of the large-diameter section 101 may be located at the same position as the proximal end 22b of the helical portion 22. The proximal end of the large-diameter section 101 may be located more distally than the proximal end 22b of the helical portion 22.

[0046] In the large-diameter section 101, the helical portion 22 may have a portion in contact with the guidewire tube 10, or the helical portion 22 may not have a portion in contact with the guidewire tube 10.

[0047] At least one of the distal end portion of the helical portion 22 and the proximal end portion of the helical portion 22 may be fixed to the guidewire tube 10. As shown in FIG. 2, the proximal end portion of the helical portion 22 may be fixed to the guidewire tube 10. As shown in FIG. 3, the distal end portion of the helical portion 22 may be fixed to the guidewire tube 10. Although not shown in the drawings, the distal end portion of the helical portion 22 and the proximal end portion of the helical portion 22 may both be fixed to the guidewire tube 10. This makes it easy to stabilize the position of the ejection hole 4.

[0048] As shown in FIGS. 2 to 4, the midpoint 22o of the helical portion 22 in the longitudinal direction x of the outer cylinder 30 does not need to be in contact with the guidewire tube 10. The midpoint 22o of the helical portion 22 in the longitudinal direction x of the outer cylinder 30 does not need to be fixed to the guidewire tube 10. With such a configuration, positional deviation between the helical portion 22 and the guidewire tube 10 can be easily tolerated, which facilitates improvement in flexibility and contributes to improvement in operability. Although not shown in the drawings, the midpoint 22o of the helical portion 22 in the longitudinal direction x of the outer cylinder 30 may be in contact with the guidewire tube 10. Furthermore, the midpoint 22o of the helical portion 22 in the longitudinal direction x of the outer cylinder 30 may be fixed to the guidewire tube 10.

[0049] As shown in Figures 2 to 4, the cryoablation catheter 100 may have a separation section 110, which is a section extending in the longitudinal direction x of the outer cylinder 30, where the guide wire tube 10 and the helical portion 22 are separated in the radial direction y of the outer cylinder 30. As can be seen from Figure 2, even if a section includes a portion on one side in the radial direction y of the outer cylinder 30 where the guide wire tube 10 and the helical portion 22 are not separated, if that section has a portion on the other side in the radial direction y of the outer cylinder 30 where the guide wire tube 10 and the helical portion 22 are separated, that section is included in the separation section 110. This makes it easier to increase the flexibility of the distal end of the cryoablation catheter 100.

[0050] The cryoablation catheter 100 may have only one separation section 110, or it may have multiple separation sections 110.

[0051] In the separation section 110, it is preferable that a gap exists between the guidewire tube 10 and the helical portion 22. This makes it easier to increase the flexibility of the distal end of the cryoablation catheter 100.

[0052] As shown in Figures 2 and 3, it is preferable that the cryoablation catheter 100 has a contact section 121, which is a section of the outer cylinder 30 extending in the longitudinal direction x, in which the guide wire tube 10 and the helical section 22 are in contact, and a non-contact section 122, which is a section of the outer cylinder 30 extending in the longitudinal direction x, in which the guide wire tube 10 and the helical section 22 are not in contact. This makes it possible to increase the flexibility of the distal end of the cryoablation catheter 100 while stabilizing the position of the injection port 4.

[0053] The cryoablation catheter 100 may have only one contact section 121, or it may have multiple contact sections 121. The cryoablation catheter 100 may have only one non-contact section 122, or it may have multiple non-contact sections 122. As shown in Figure 4, the cryoablation catheter 100 may have a non-contact section 122 but not a contact section 121.

[0054] Preferably, the length of the non-contact section 122 in the longitudinal direction x of the outer cylinder 30 is longer than the length of the contact section 121 in the longitudinal direction x of the outer cylinder 30. This makes it easier to increase the flexibility of the distal end of the cryoablation catheter 100. However, it is also permissible for the length of the non-contact section 122 in the longitudinal direction x of the outer cylinder 30 to be shorter than the length of the contact section 121 in the longitudinal direction x of the outer cylinder 30. If the cryoablation catheter 100 has multiple contact sections 121, the length of the contact section 121 in the longitudinal direction x of the outer cylinder 30 refers to the sum of the lengths of the outer cylinder 30 in the longitudinal direction x measured in each contact section 121. If the cryoablation catheter 100 has multiple non-contact sections 122, the length of the non-contact section 122 in the longitudinal direction x of the outer cylinder 30 refers to the sum of the lengths of the outer cylinder 30 in the longitudinal direction x measured in each non-contact section 122.

[0055] The length of the non-contact section 122 in the longitudinal direction x of the outer cylinder 30 is preferably at least twice, more preferably at least three times, and even more preferably at least four times, the length of the contact section 121 in the longitudinal direction x of the outer cylinder 30. This makes it easier to increase the flexibility of the distal end of the cryoablation catheter 100.

[0056] As shown in Figures 2 to 4, the gas supply tube 20 may have a linear portion 23 extending in the longitudinal direction x of the outer cylinder 30, proximal to the helical portion 22.

[0057] As shown in Figure 4, the linear portion 23 is fixed to the guide wire tube 10, and the helical portion 22 does not necessarily have to be fixed to the guide wire tube 10. Fixing the linear portion 23 to the guide wire tube 10 makes it easier to improve pushability. The linear portion 23 is in contact with the guide wire tube 10, and the helical portion 22 does not necessarily have to be in contact with the guide wire tube 10.

[0058] As shown in Figures 2 and 3, the linear portion 23 does not have to be fixed to the guide wire tube 10. In this case, a part of the helical portion 22 may be fixed to the guide wire tube 10. The linear portion 23 may not be in contact with the guide wire tube 10, while the helical portion 22 may be in contact with the guide wire tube 10.

[0059] As shown in Figures 2 to 4, it is preferable that a gap exists between the inner surface 22c of the helical portion 22 and the outer surface of the guide wire tube 10. Furthermore, it is preferable that no member is placed between the inner surface 22c of the helical portion 22 and the outer surface of the guide wire tube 10. This makes it easier to tolerate misalignment between the helical portion 22 and the guide wire tube 10, thereby increasing flexibility and contributing to improved operability.

[0060] Gases such as nitrous oxide, carbon dioxide, and argon can be used in the cryoablation catheter 100.

[0061] The hub 90 may be connected to the proximal part of the outer cylinder 30. The hub 90 may be fixed to the outer cylinder 30. The hub 90 can be fixed by adhesive bonding, welding, screws, etc.

[0062] The hub 90 can be shaped, for example, cylindrical or hollow columnar, and may have an internal lumen.

[0063] The cryoablation catheter 100 may have a tip 91 provided at its distal end. Preferably, the tip 91 has a lumen that serves as a guide wire insertion passage.

[0064] Examples of materials that make up the tip 91 include polyurethane resin, polyester resin, and polyamide resin. Preferably, the tip 91 is made of a material with lower rigidity than the material that makes up the outer cylinder 30.

[0065] The length of the cryoablation catheter 100 from the distal end to the proximal end can be, for example, 200 mm or more, 250 mm or more, 300 mm or more, etc. Alternatively, the length of the cryoablation catheter 100 from the distal end to the proximal end can be, for example, 2500 mm or less, 2450 mm or less, 2400 mm or less, etc.

[0066] This application claims the benefit of priority based on Japanese Patent Application No. 2025-038318, filed on 11 March 2025. The entire specification of Japanese Patent Application No. 2025-038318, filed on 11 March 2025, is incorporated herein by reference.

[0067] 1: Guidewire lumen 2: Gas supply lumen 3: Gas discharge lumen 4: Injection port 10: Guidewire tube 10e: Lumen 20: Gas supply tube 20c: Inner surface 20d: Outer surface 20e: Lumen 22: Helical section 22a: Distal end 22b: Proximal end 22c: Inner surface 22d: Outer surface 22e: Lumen 22o: Midpoint 23: Straight section 30: Outer cylinder 30e: Lumen 52: Guidewire port 60: Balloon 61: Distal sleeve section 62: Expand / contract section 63: Proximal sleeve section 90: Hub 91: Tip 100: Cryoablation catheter 101: Large diameter section 110: Separation section 121: Contact section 122: Non-contact section x: Longitudinal direction of the outer cylinder y: Radial direction of the outer cylinder

Claims

1. A cryoablation catheter comprising: an outer cylinder; a balloon provided at the distal end of the outer cylinder; a guidewire tube disposed within the lumen of the outer cylinder and inside the balloon; a gas supply tube disposed within the lumen of the outer cylinder and inside the balloon, having a helical portion wound around the guidewire tube, with injection holes provided in the helical portion for injecting gas toward the inside of the balloon; and a gas discharge lumen located between the outer cylinder, the guidewire tube, and the gas supply tube, wherein the helical portion has an inner surface which is the outer surface of the gas supply tube and is located on the guidewire tube side, and a large-diameter section in which the lumen of the helical portion, located radially inward from the inner surface of the helical portion, has a diameter larger than the outer diameter of the guidewire tube.

2. The cryoablation catheter according to claim 1, wherein at least one of the distal end and the proximal end of the helical portion is fixed to the guidewire tube.

3. The cryoablation catheter according to claim 1 or 2, wherein the midpoint of the helical portion in the longitudinal direction of the outer cylinder is not in contact with the guide wire tube.

4. The cryoablation catheter according to claim 1 or 2, having a separation section which is a section extending in the longitudinal direction of the outer cylinder in which the guide wire tube and the helical portion are separated in the radial direction of the outer cylinder.

5. The cryoablation catheter according to claim 4, wherein a gap exists between the guidewire tube and the helical portion in the separation section.

6. A cryoablation catheter according to claim 1 or 2, comprising: a contact section which is a section extending in the longitudinal direction of the outer cylinder in which the guide wire tube and the helical portion are in contact; and a non-contact section which is a section extending in the longitudinal direction of the outer cylinder in which the guide wire tube and the helical portion are not in contact.

7. The cryoablation catheter according to claim 6, wherein the length of the non-contact section in the longitudinal direction of the outer cylinder is longer than the length of the contact section in the longitudinal direction of the outer cylinder.

8. The cryoablation catheter according to claim 7, wherein the length of the non-contact section in the longitudinal direction of the outer cylinder is at least twice the length of the contact section in the longitudinal direction of the outer cylinder.

9. The cryoablation catheter according to claim 1, wherein the gas supply tube has a linear portion extending in the longitudinal direction of the outer cylinder proximal to the helical portion, the linear portion being fixed to the guide wire tube, and the helical portion not being fixed to the guide wire tube.

10. The cryoablation catheter according to claim 2, wherein the gas supply tube has a linear portion extending in the longitudinal direction of the outer cylinder proximal to the helical portion, and the linear portion is not fixed to the guide wire tube.

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