Ablation catheter and method for manufacturing the same

Abstract

To provide an ablation catheter easy to operate with a guide wire inserted into a guide wire lumen.SOLUTION: An ablation catheter 11 comprises: a hollow shaft 22; a balloon 21 provided on the distal end side of the shaft 22; an optical fiber 52 inserted into the shaft 22 and propagating and emitting laser light to the outside; and a tip member 61 provided at the distal end side of the balloon 21. The tip member 61 has a guide wire lumen open at the distal end 69 and the proximal end 70 of the tip member 61.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an ablation catheter that irradiates laser light and a method for manufacturing an ablation catheter. [Background technology]

[0002] It is known that ablation of nerves near the adventitia of the renal artery leads to a long-term reduction in blood pressure. Such a method of ablation of nerves in the renal artery is called renal artery sympathetic nerve ablation or renal denervation (hereinafter, also simply called "ablation"). Such ablation is expected to be a treatment for hypertension. In ablation, an ablation catheter is used (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2015-217215 A Summary of the Invention [Problem to be solved by the invention]

[0004] It is said that ablation is preferably performed on the side branches of the renal arteries, which are closer to the kidney than the aorta, and therefore, to allow for more precise vessel selection, the ablation catheter is guided to the renal arteries by a guidewire.

[0005] In Patent Document 1, the guidewire tube in which the guidewire lumen is formed is located on the proximal side of the balloon. Therefore, it is difficult to guide the balloon, which is located on the distal side of the guidewire tube, into the renal artery, which has a relatively small diameter. In addition, the guidewire tube is juxtaposed to the shaft, which may increase the outer diameter of the shaft or reduce the flexibility of the shaft.

[0006] On the other hand, in an ablation catheter, if a guidewire lumen is used that is inserted into the internal space of the shaft or balloon and opens at the distal end of the catheter, the tube that defines the guidewire lumen and the optical path of the laser light are arranged so as to overlap in the radial direction, so that the laser light emitted in the radial direction may be blocked by the tube, which may prevent accurate ablation. In addition, the outer diameter of the catheter may become large, or the flexibility of the catheter may decrease.

[0007] The present invention has been made in consideration of the above-mentioned circumstances, and an object of the present invention is to provide an ablation catheter that has good operability with a guidewire inserted through the guidewire lumen. [Means for solving the problem]

[0008] (1) An ablation catheter according to the present invention comprises a hollow shaft, a balloon provided on the distal end side of the shaft, an optical fiber inserted through the shaft for propagating laser light and emitting it to the outside, and a tip member provided on the distal end side of the balloon, the tip member having a guidewire lumen opening at the distal end and the proximal end of the tip member.

[0009] Since the guidewire is inserted into the guidewire lumen formed in the tip member provided on the distal end side of the balloon, the tip member follows the guidewire, and the balloon can be easily guided to the renal artery. In addition, since there is no member that divides the guidewire lumen inside the balloon, the laser light is not affected, and ablation can be performed with high precision.

[0010] (2) Preferably, a guidewire lumen is formed only in the tip member.

[0011] The guide wire can be detached from the ablation catheter simply by pulling the guide wire out of the guide wire lumen formed in the distal end member of the ablation catheter. In addition, the outer diameter of the shaft can be reduced and the shaft can be made flexible.

[0012] (3) Preferably, the catheter further comprises a tube that is inserted through the shaft and the balloon and protrudes distally beyond the distal end of the balloon. The tube opens within the balloon. The distal member has a distal tip located distally beyond the tube and a cover tube connecting the distal tip and the distal end of the tube. The guidewire lumen is at least partially defined by the distal tip and opens at the proximal end of the cover tube.

[0013] The configuration of the tip member is simplified, and the tip member can easily follow the curvature of a blood vessel.

[0014] (4) Preferably, the tip protrudes distally beyond the distal end of the cover tube, and the tip has a hardness less than that of the cover tube.

[0015] The tip member can easily follow the curvature of the blood vessel, etc. Also, the tip member is less likely to damage the blood vessel.

[0016] (5) A method for manufacturing an ablation catheter according to the present invention includes an assembly step of covering a distal tip, through which a rod-shaped mandrel is inserted, with a cover tube so that the base end of the mandrel protrudes from the proximal end of the cover tube; a heating step of integrating the distal end of the tube inserted into a balloon, the distal tip, and the cover tube by heating; and a withdrawal step of withdrawing the mandrel from the integrated tube, the distal tip, and the cover tube.

[0017] An ablation catheter having a guidewire lumen formed in the tip member can be easily manufactured. Effect of the Invention

[0018] According to the present invention, an ablation catheter that has good operability using a guidewire inserted through the guidewire lumen can be realized. [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 is a diagram showing the configuration of a catheter system 10 equipped with an ablation catheter 11 according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view of the distal end side of ablation catheter 11 before guidewire 80 is removed. [Diagram 3] FIG. 3 is a cross-sectional view of the distal end of ablation catheter 11 after balloon 21 is inflated. [Figure 4] FIG. 4 is a cross-sectional view of the vicinity of the connector portion 26. As shown in FIG. [Diagram 5] FIG. 5(A) is a schematic diagram showing a state in which the ablation catheter 11 is being inserted into a renal artery 91, and FIG. 5(B) is a schematic diagram showing a state in which the ablation catheter 11 has been inserted into the renal artery 91. [Figure 6] FIG. 6 is a flow chart showing a method for manufacturing the ablation catheter 11. [Figure 7] FIG. 7 is a schematic cross-sectional view showing a state assembled in the assembly process. [Figure 8] FIG. 8 is a schematic cross-sectional view showing the state before welding in which the fluid tube 23 and the tip member 61 are combined in the third welding step. [Figure 9] FIG. 9 is a cross-sectional view of the distal end side of the ablation catheter 11 according to the first modification of the present invention before the guide wire 80 is removed. [Figure 10] FIG. 10 is a schematic cross-sectional view showing a state assembled by an assembly process according to the second modified example of the present invention. [Figure 11]FIG. 11 is a cross-sectional view of the distal end side of the ablation catheter according to the second modification before the guide wire 80 is removed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, a preferred embodiment of the present invention will be described. Note that this embodiment is merely one embodiment of the present invention, and it goes without saying that the embodiment can be changed without departing from the gist of the present invention.

[0021] [Catheter System 10] The catheter system 10 is used to perform ablation on nerves in, for example, a renal artery 91 (see Figs. 5(A) and 5(B)). As shown in Fig. 1, the catheter system 10 includes an ablation catheter 11, a circuit 12, a driving device 13, a laser light generating device 14, and a rotating device 15. The catheter system 10 may also be used for ablation of cardiac tissue.

[0022] [Ablation Catheter 11] 1, 2, and 3, the ablation catheter 11 has a shaft 22 with a balloon 21 provided at the tip side. The shaft 22 is a long member in an axial direction 90. The shaft 22 is a tubular body that bends elastically so as to be curved with respect to the axial direction 90. The direction in which the shaft 22 extends in an unbent state is referred to as the axial direction 90 in this specification. The ablation catheter 11 may be used in catheter ablation surgery (myocardial ablation surgery) for arrhythmia.

[0023] 2 and 3, the fluid tube 23 and the light guide tube 51 are located in the internal space of the shaft 22. The outer diameter and the inner diameter of the shaft 22 do not necessarily have to be constant in the axial direction 90. The material of the shaft 22 is synthetic resin, stainless steel, etc., and the shaft 22 does not necessarily have to be made of only one type of material, but may be made of a plurality of materials. The internal space of the fluid tube 23 is the first lumen 24. The space inside the shaft 22 and outside the fluid tube 23 is the second lumen 25.

[0024] In this embodiment, the proximal end side or base end side refers to the rear side (the right side in FIG. 1) in the direction in which the ablation catheter 11 is inserted into the blood vessel. The distal end side refers to the front side (the left side in FIG. 1) in the direction in which the ablation catheter 11 is inserted into the blood vessel.

[0025] A balloon 21 is provided on the distal end side of the shaft 22. The balloon 21 elastically expands when a fluid (liquid) flows into the internal space, and contracts when the fluid flows out of the internal space. Fig. 1 shows the balloon 21 in a contracted state. The fluid circulated through the balloon 21 is not particularly limited, but for example, in ablation of the renal artery 91, a mixed solution of physiological saline and a contrast agent is used.

[0026] The fluid tube 23 penetrates the balloon 21. The distal end 77 of the fluid tube 23 protrudes from the balloon 21 toward the distal end side. The fluid tube 23 has openings 71 and 72 located in the internal space of the balloon 21. The openings 71 and 72 penetrate the peripheral wall of the fluid tube 23, respectively. The first lumen 24 communicates with the internal space of the balloon 21 through the openings 71 and 72. The openings 71 and 72 are located at different positions in the circumferential direction of the axial direction 90. The distal end 77 of the fluid tube 23 protrudes from the balloon 21, is a part of the fluid tube 23 on the distal end side in the axial direction 90, and includes the outer circumferential surface and the end surface. The fluid tube 23 is an example of a tube that is inserted into the internal space of the shaft 22 and the balloon 21 and protrudes from the balloon 21 toward the distal end side.

[0027] The second lumen 25 , which is the internal space of the shaft 22 , is connected to the proximal end side of the balloon 21 and communicates with the internal space of the balloon 21 .

[0028] The light-guiding tube 51 is a tubular body that can bend elastically so as to be curved in the axial direction 90. The distal end of the light-guiding tube 51 reaches the internal space of the balloon 21, and the proximal end extends to the outside through the connector portion 26. The light-guiding tube 51 is movable along the axial direction 90 relative to the connector portion 26, and is rotatable around the axial direction 90.

[0029] An optical fiber 52 is positioned in the internal space of the light guiding tube 51. That is, the optical fiber 52 is inserted into the shaft 22. An end face 57 at the distal end of the optical fiber 52 is perpendicular to the axis. The optical fiber 52 propagates the laser light generated in the laser light generating device 14 and irradiated onto the base end of the optical fiber 52 toward the distal end. The optical fiber 52 is appropriately selected to have a refractive index that causes total reflection at the wavelength of the laser light.

[0030] A housing 53 is attached to the distal end of the light-guiding tube 51. The housing 53 is located in the internal space of the balloon 21. The housing 53 is tubular, and the optical fiber 52 is located in the internal space. The housing 53 has an opening 54 penetrating the peripheral wall. A reflector 55 is located in the housing 53 on the distal end side of the opening 54. In the internal space of the housing 53, an end face 57 of the optical fiber 52 and the reflector 55 are spaced apart, and the opening 54 is located between the end face 57 of the optical fiber 52 and the reflector 55.

[0031] The reflecting material 55 is located in the internal space of the housing 53, facing the end face 57 of the optical fiber 52 in the axial direction 90. The reflecting material 55 reflects the laser light emitted from the optical fiber 52 in the internal space of the balloon 21. The reflected laser light is emitted in a direction perpendicular to the axial direction 90. A reflecting surface 56 of the reflecting material 55 facing the end face 57 is inclined at an angle of 45 degrees with respect to the axial direction 90. The reflecting surface 56 is exposed to the outside of the housing 53 through an opening 54 of the housing 53. The reflecting material 55 is a cylindrical body made of metal, optical fiber, resin, etc. A metal layer is laminated on the reflecting surface 56 of the reflecting material 55. The metal layer is formed on the surface of the reflecting material 55 by plating or sputtering, for example, using nickel, gold, aluminum, chromium, etc. alone or in combination. The direction in which the laser light reflected by the reflecting material 55 is emitted may be any direction intersecting with the axial direction 90.

[0032] The optical fiber 52 and the reflector 55 are rotatable about the axis (axial direction 90) and slidable in the axial direction 90 together with the light guiding tube 51 while maintaining the positional relationship between the end face 57 and the reflecting surface 56, i.e., the separation distance and the angle of the reflecting surface 56. The rotation and sliding of the optical fiber 52 and the reflector 55 are controlled by directly or indirectly manipulating the base end side of the light guiding tube 51 extended from the connector portion 26. Specifically, the light guiding tube 51 is rotated and slid by applying a driving force from the rotating device 15 to the base end side of the light guiding tube 51.

[0033] The ablation catheter 11 has a tip member 61 provided on the distal end side of the balloon 21. A guidewire lumen 62 is formed in the tip member 61. A guidewire 80 is passed through the guidewire lumen 62, and the ablation catheter 11 is guided along the guidewire 80 to a desired position inside the patient's body. As shown in FIG. 5(B), the desired position is, for example, inside the renal artery 91 on the kidney side of a branch 92 of the renal artery 91. Note that the guidewire lumen provided in the ablation catheter 11 is the guidewire lumen 62 only.

[0034] As shown in FIGS. 2 and 3, the tip member 61 has a cover tube 63 a part of which is connected to the distal end portion 77 of the fluid tube 23 , and a tip tip 64 located in the internal space of the cover tube 63 .

[0035] The cover tube 63 is made of resin. The cover tube 63 has an opening 94 on the proximal end side and an opening 95 on the distal end side. The openings 94, 95 communicate the internal space of the cover tube 63 with the external space. The opening 94 faces in a direction intersecting the axial direction 90 as the cover tube 63 is bent during welding. The opening 95 faces in the axial direction 90.

[0036] The outer peripheral surface on the proximal end side of the cover tube 63 is welded to the outer peripheral surface or inner peripheral surface of the distal end portion 77. When the distal end portion 77 is welded to the tip member 61, the opening periphery of the distal end portion 77 including the outer peripheral surface and the inner peripheral surface is welded to the outer peripheral surface of the tip member 61. The distal end portion 77 is liquid-tightly sealed, for example, by the internal space being crushed and the inner peripheral surfaces being welded to each other. Note that the distal end portion 77 may be liquid-tightly sealed by welding the outer peripheral surface of the tip member 61 and the inner peripheral surface of the distal end portion 77.

[0037] The cover tube 63 surrounds the tip 64. The inner circumferential surface of the cover tube 63 is welded to the outer circumferential surface of the tubular tip 64. The distal end of the cover tube 63 is at the same position in the axial direction 90 as the distal end of the tip 64. The hardness of the cover tube 63 is, for example, smaller than the hardness of the fluid tube 23.

[0038] The tip 64 is made of a resin containing a material to be imaged. Examples of the resin include polyurethane, and examples of the material to be imaged include barium sulfate, bismuth oxide, and bismuth subcarbonate. The hardness of the tip 64 is less than that of the cover tube 63.

[0039] The distal tip 64 is formed in a tubular shape, and the internal space defines the guidewire lumen 62. The distal tip 64 has an opening 67 on the proximal end side. The internal space of the distal tip 64 communicates with the external space via the opening 67. The opening 67 is located inside the opening on the proximal end side of the cover tube 63. The opening 67 is an opening on the proximal end side of the guidewire lumen 62. The opening 67 faces in a direction intersecting the axial direction 90 as the distal tip 64 and the cover tube 63 deform during welding.

[0040] The tip tip 64 has an opening 68 at its distal end. The opening 68 communicates the internal space of the tip tip 64 with the external space. The opening 68 faces the axial direction 90. That is, the opening 68 opens at the distal end surface of the tip member 61. The guidewire lumen 62 opens at the distal end 69 and the proximal end 70 of the tip member 61 through the openings 67 and 68. The distal end 69 of the tip member 61 refers to the end surface on the distal end side of the tip member 61 facing the axial direction 90. The proximal end 70 of the tip member 61 is a part of the tip member 61 that is closer to the proximal end than the center in the axial direction 90, and includes the outer circumferential surface and the end surface.

[0041] The distal end 77, cover tube 63, and tip 64 shown in Figures 2 and 3 are an example of the shape after welding, and the boundaries between the distal end 77, cover tube 63, and tip 64 are shown. The distal end 77, cover tube 63, and tip 64 may be integrated by welding, and the boundaries between them may be absent or unclear. The distal end 77, cover tube 63, and tip 64 may be partially mixed together. Therefore, the distal end 77, cover tube 63, and tip 64 do not have to have the configuration shown in Figures 2 and 3, and may be formed as an integrated entity with unclear boundaries between them.

[0042] 1, a connector portion 26 is provided on the base end side of the shaft 22. The connector portion 26 is a portion that a practitioner holds when operating the ablation catheter 11. An optical fiber 52 is inserted into the connector portion 26. A first port 27 and a second port 28 are provided in the connector portion 26 separately from the insertion port for the optical fiber 52.

[0043] 4, the first port 27 is continuous with the first lumen 24. Through the first port 27, the fluid to be returned to the balloon 21 flows into the first lumen 24. The second port 28 is continuous with the second lumen 25. Through the second port 28, the fluid to be returned to the balloon 21 flows out from the second lumen 25. Inside the connector portion 26, the first port 27 and the second port 28 are liquid-tightly separated by O-rings 73 and 74, respectively. In addition, the periphery of the light-guiding tube 51 is liquid-tightly secured by an O-ring 75.

[0044] [Circuit 12] The circuit 12 is used to circulate a fluid through the ablation catheter 11. As shown in Fig. 1, the circuit 12 includes a buffer tank 31, a first flow path 32, a pressure sensor 33, a second flow path 34, and a check valve 35 provided in the second flow path 34.

[0045] The buffer tank 31 stores the fluid to be circulated through the ablation catheter 11 and the circuit 12. The buffer tank 31 is, for example, a flexible bag. Although not shown in the drawings, the buffer tank 31 has ports to which the first flow path 32 and the second flow path 34 are connected.

[0046] The first flow path 32 is composed of a flexible synthetic resin tube 36. The first flow path 32 may be composed of one synthetic resin tube, or may be composed of a plurality of synthetic resin tubes connected by a joint or the like. The first flow path 32 connects the buffer tank 31 and the first port 27 so that a fluid can flow therethrough.

[0047] The second flow path 34 is composed of a flexible synthetic resin tube 37. The second flow path 34 may be composed of one synthetic resin tube, or may be composed of a plurality of synthetic resin tubes connected by a joint or the like. The second flow path 34 connects the buffer tank 31 and the second port 28 so that the fluid can flow therethrough. Note that a known joint may be used to connect each flow path and each port.

[0048] A pressure sensor 33 is provided between the first port 27 and the pump 41 in the first flow path 32. The pressure sensor 33 detects the pressure of the fluid in the first flow path 32 and outputs a detection signal corresponding to the detected pressure. For example, a diaphragm type pressure sensor is used as the pressure sensor 33. The detection signal of the pressure sensor 33 is output to the controller 44.

[0049] A check valve 35 is provided in the second flow path 34. The check valve 35 allows the fluid to flow in one direction and prevents the fluid from flowing in the other direction by moving a valve provided in the housing due to the back pressure of the fluid. The check valve 35 allows the fluid to flow in one direction in the second flow path 34, that is, from the second port 28 to the buffer tank 31. On the other hand, the check valve 35 prevents the fluid from flowing from the buffer tank 31 to the second port 28 in the second flow path 34.

[0050] [Driver 13] The driving device 13 has a pump 41, a display 42, an input I / F 43, and a controller 44. The pump 41 is preferably a roller pump. A synthetic resin tube 36 that constitutes the first flow path 32 is set in the pump 41. The pump 41 can be driven in both directions.

[0051] As the display 42, for example, a liquid crystal display (short for Liquid Crystal Display), an organic EL display (short for Organic Electro-Luminescence Display), or the like is adopted.

[0052] The input I / F 43 is a user interface that accepts an input operation by a user. Specifically, the input I / F 43 is a film-like touch sensor superimposed on the display 42. The input I / F 43 may also be a button provided in the driving device 13. The input I / F 43 accepts a user operation and outputs various signals according to the accepted operation to the controller 44. Examples of the operation signal include inflation of the balloon 21, deflation of the balloon 21, etc.

[0053] The controller 44 has a memory, a CPU, etc. (not shown). A program is set in the controller 44 in advance, and the controller 44 controls the operation of the pump 41, the operation of the laser light generating device 14, and the operation of the rotating device 15 in accordance with the program.

[0054] [Laser light generating device 14] The laser light generating device 14, for example, is a device in which light from an excitation source is given to a laser medium, and is transmitted and output by reflection of an optical resonator. The laser light output from the laser light generating device 14 is preferably a continuous wave, and the wavelength of the laser light is preferably in the range of 400 to 2000 nm. The laser light generating device 14 is connected to the base end of the optical fiber 52, and the laser light output from the laser light generating device 14 is irradiated onto the base end face of the optical fiber 52.

[0055] [Rotating device 15] The rotating device 15 applies a driving force to rotate and slide the base end side of the light-guiding tube 51 in the axial direction 90, and a mechanism combining a motor, a slider, etc. may be used. Note that the rotating device 15 is not essential, and the light-guiding tube 51 may be rotated and slid in the axial direction 90 by the practitioner handling the base end side of the light-guiding tube 51.

[0056] [How to use Ablation Catheter 11] An example of a method of using the ablation catheter 11 in the catheter system 10 will be described below. As shown in Fig. 5(A), the guidewire 80 is fed to a predetermined position in the renal artery 91 on the kidney side from a branch 92 in the renal artery 91. The ablation catheter 11 is formed such that the guidewire 80 is inserted into the guidewire lumen 62 outside the body. Then, the ablation catheter is fed along the guidewire 80 to a predetermined position in the renal artery 91 inside the body.

[0057] As shown in Fig. 5(B), after the ablation catheter 11 has been sent to a predetermined position, the guide wire 80 is removed from the ablation catheter 11. After the guide wire 80 is removed from the ablation catheter 11, the balloon 21 is inflated and a laser irradiation operation is performed. In the laser irradiation operation, the rotating device 15 rotates the light guiding tube 51 and the reflecting material 55 in the housing 53, so that the laser can be irradiated in all circumferential directions around the axis of the shaft 22. After the laser irradiation, the balloon 21 is deflated and the ablation catheter 11 is withdrawn.

[0058] [Method of manufacturing ablation catheter 11] As shown in FIG. 6, the method of manufacturing the ablation catheter 11 includes a first welding step (S1), an assembly step (S2), a second welding step (S3), a third welding step (S4), and a pulling step (S5).

[0059] [First welding process] In the first welding step, the balloon 21 is welded to the fluid tube 23 and the shaft 22 by heating. The inner peripheral surface of the distal end side of the balloon 21 is welded to the outer peripheral surface of the fluid tube 23 that is inserted into and protrudes from the shaft 22, and the inner peripheral surface of the proximal end side of the balloon 21 is welded to the outer peripheral surface of the distal end of the shaft 22.

[0060] [Assembly process] As shown in FIG. 7, in the assembly process, the tip 64, the cover tube 63, and the mandrel 81 are assembled.

[0061] During welding, the mandrel 81 maintains the internal space of the tip 64 and the connection between the proximal end opening 67 and the distal end opening 68. The mandrel 81 is, for example, a metal bar having a circular cross section.

[0062] The mandrel 81 is inserted into the internal space of the tip 64. The tip 64 is inserted into the cover tube 63.

[0063] The distal end of the mandrel 81 protrudes from the opening 68 of the distal tip 64, and the proximal end of the mandrel 81 protrudes from the opening 67 of the distal tip 64. The mandrel 81 may be inserted into the distal tip 64 after the distal tip 64 has been inserted into the cover tube 63.

[0064] The distal end of the tip 64 is at the same position in the axial direction 90 as the distal end of the cover tube 63 .

[0065] [Second welding process] In the second welding step, the assembled tubular distal tip 64 and the cover tube 63 are heated and welded together to form a single unit. In the second welding step, the cover tube 63 is heated from the outside by a heater (not shown). The inner circumferential surface of the heated cover tube 63 is welded to the outer circumferential surface of the distal tip 64. The welded cover tube 63 constitutes a part of the proximal end portion 70.

[0066] [Third welding process] In the third welding step, the fluid tube 23 to which the balloon 21 is welded and the tip member 61 to which the balloon 21 is welded in the second welding step are welded together by heating to be integrated. The distal end 77 of the fluid tube 23 is cut in advance so that the end face is not perpendicular to the axis. As shown in FIG. 8, the distal end 77 is attached to the tip member 61 with the direction in which it protrudes from the balloon 21 aligned with the direction in which the mandrel 81 continues. At this time, a part of the outer circumferential surface of the distal end 77 abuts against a part of the outer circumferential surface of the tip member 61. The end face of the distal end 77 is also oriented toward the outer circumferential surface of the tip member 61.

[0067] In the third step, in a state where the fluid tube 23 and the tip member 61 are joined together, the distal end 77 is heated from the outside by a heater (not shown). Heat is transferred from the distal end 77 to the cover tube 63 and the tip tip 64 in this order. The distal end 77 is liquid-tightly sealed by welding the opening periphery of the distal end 77, including the outer circumferential surface and the inner circumferential surface, to the outer circumferential surface of the tip member 61, for example, by crushing the internal space of the distal end 77 and welding the inner circumferential surfaces of the distal end 77 to each other. The distal end 77 may be liquid-tightly sealed by welding the outer circumferential surface of the tip member 61 to the inner circumferential surface of the distal end 77. The second welding step and the third welding step are examples of a heating step.

[0068] [Pulling process] After the third welding step, the tip member 61 is naturally cooled. After cooling, the mandrel 81 is pulled out from the tip member 61. The space held by the mandrel 81 becomes the guidewire lumen 62.

[0069] [Effects of this embodiment] In this embodiment, the guidewire 80 is inserted into the guidewire lumen 62 formed in the tip member 61 located distal to the balloon 21, so that the tip member 61 follows the guidewire 80, making it possible to easily guide the balloon to the renal artery.

[0070] Furthermore, since there is no member that divides the guidewire lumen 62 inside the balloon 21, the laser light is not affected, and ablation can be performed with high precision.

[0071] Moreover, since the guidewire lumen 62 is formed only in the tip member 61, the guidewire 80 can be separated from the ablation catheter 11 simply by pulling the guidewire 80 out of the guidewire lumen 62 formed in the tip member 61 of the ablation catheter 11. Furthermore, the outer diameter of the shaft on the proximal end side from the balloon can be reduced, and the shaft can be made flexible.

[0072] Furthermore, since no guidewire lumen is provided in the internal space of the shaft 22 and the balloon 21, the optical fiber 52 can be positioned at the center of the diameter of the longitudinal cross section of the shaft 22 or the balloon 21. This makes it possible to keep the distance that the emitted laser light travels to reach the blood vessel constant.

[0073] In addition, since the tip member 61 consists of the tip chip 64 located distal to the fluid tube 23 and the cover tube 63 connecting the tip chip 64 to the distal end of the fluid tube 23, the configuration of the tip member 61 is simplified and the tip member 61 can easily follow the curvature of a blood vessel, etc.

[0074] The hardness of the cover tube 63 is less than that of the fluid tube 23 and greater than that of the tip tip 64. A part of the inner circumferential surface of the distal end portion 77 of the fluid tube 23 is welded to a part of the outer circumferential surface of the cover tube 63. The cover tube 63 also surrounds the tip tip 64. By reducing the difference in hardness between the fluid tube 23 and the tip tip 64 in this manner, the tip tip 64 is prevented from breaking and the tensile strength of the tip member 61 is improved.

[0075] Moreover, according to the method for manufacturing the ablation catheter 11 of this embodiment, the ablation catheter 11 in which the guidewire lumen 62 is formed in the tip member 61 can be easily manufactured.

[0076] Furthermore, in the third welding process, since the distal end 77 is located outside the tip member 61 and the heat generated by heating is transmitted in the order of the distal end 77, the cover tube 63, and the tip tip 64, the operator can visually confirm the welding between the distal end 77 and the tip member 61, and is prevented from ending the welding work before the welding between the distal end 77 and the tip member 61 is completed.

[0077] Furthermore, by welding the balloon 21 to the fluid tube 23 and the shaft 22 before the assembly process rather than after the second welding process, the balloon 21 is prevented from welding to the outer peripheral surface of the cover tube 63, and liquid leakage from the distal end of the balloon 21 is prevented.

[0078] In addition, since the distal end 77 of the fluid tube 23 is cut, in the third welding step, the distal end 77 can be welded to the tip member 61 while the direction in which the distal end 77 protrudes from the balloon 21 is aligned with the direction in which the mandrel 81 continues. This eliminates the need to adjust the angle of the direction in which the distal end 77 protrudes from the balloon 21 relative to the extension direction of the cylindrical tip member 61, improving the workability of welding.

[0079] Furthermore, by changing the diameter of mandrel 81 without changing the diameter of shaft 22, the diameter of the guidewire lumen can be easily changed.

[0080] [Variation 1] In the above embodiment, the position of the distal end of the cover tube 63 in the axial direction 90 is the same as the distal end of the tip 64. Alternatively, the distal end of the cover tube 63 may be located proximal to the distal end of the tip 64 in the axial direction 90.

[0081] 9, the tip member 161 has a cover tube 163 that partially covers the distal end 77 of the fluid tube 23, and a tip tip 64 whose base end is located in the internal space of the cover tube 163. The cover tube 163 is made of resin. The hardness of the cover tube 163 is greater than the hardness of the tip tip 64, for example.

[0082] The cover tube 163 has an opening 194 on the proximal end side and an opening 195 on the distal end side. The openings 194, 195 communicate the internal space and the external space of the cover tube 163. The opening 194 faces in a direction intersecting the axial direction 90 when the cover tube 163 is bent during welding. The opening 195 faces in the axial direction 90.

[0083] The outer circumferential surface of the cover tube 163 is welded to the inner circumferential surface of the distal end 77 of the fluid tube 23. The cover tube 163 surrounds the base end of the tip 64. The inner circumferential surface of the cover tube 163 is welded to the outer circumferential surface of the proximal end of the tubular tip 64. The distal end of the cover tube 163 is located proximally from the distal end of the tip 64 in the axial direction 90, and the distal end 69 of the tip 64 protrudes from the distal end of the cover tube 163. The hardness of the tip 64 is smaller than that of the cover tube 163. The opening 67 of the tip 64 is located inside the opening 194 of the cover tube 163. The opening 68 of the tip 64 is located distally from the opening 195 of the cover tube 163 in the axial direction 90.

[0084] [Effects of Modification Example 1] The distal tip 64 protrudes further toward the distal end side than the distal end of the cover tube 163, and the hardness of the distal tip 64 is less than that of the cover tube 163, so that the distal member 61 can easily follow the curvature of the blood vessel. In addition, the distal member 61 is less likely to damage the blood vessel. In addition, the distal tip 64 has a smaller outer diameter than the cover tube 163, so that the diameter of the tip of the ablation catheter can be reduced.

[0085] [Variation 2] In the above embodiment, the distal end 77 of the fluid tube 23 is welded to the tip member 61 in the third welding step, but it may be welded to the tip member 61 in the second welding step. In Modification 2, an example will be described in which the distal end 77 of the fluid tube 23 is welded to the cover tube 263 and the tip tip 64 in the second welding step, and the third welding step is omitted. Note that instead of the cover tube 63, for example, a cover tube 263 having an inner diameter larger than that of the cover tube 63 is used. The second welding step of the modification is an example of a heating step.

[0086] The manufacturing method of the ablation catheter of the second modification includes a first welding step, an assembly step, a second welding step, and a pulling step.

[0087] [Assembly process] As shown in Fig. 10, in the assembly process, the fluid tube 23 to which the balloon 21 is welded, the distal tip 64, the cover tube 263, and the mandrel 81 are assembled. The proximal end of the cover tube 263 is flared in advance. The flaring is performed by a known method. Since the proximal end of the cover tube 263 is flared, the fluid tube 23 and the distal tip 64 can be easily inserted into the cover tube 263.

[0088] The mandrel 81 is inserted into the internal space of the tip 64. The tip 64 is inserted into the cover tube 263. In addition, the distal end 77 of the fluid tube 23 is inserted into the cover tube 263.

[0089] The mandrel 81 has a tip end that protrudes from the opening 68 of the tip tip 64 and a base end that protrudes from the opening 67 of the tip tip 64. The mandrel 81 may be inserted into the tip tip 64 after the tip tip 64 and the distal end 77 of the fluid tube 23 have been inserted into the cover tube 263.

[0090] The distal end of the tip 64 is located at the same position in the axial direction 90 as the distal end of the cover tube 263. Note that it is preferable that a portion of the distal end portion 77 of the fluid tube 23 overlaps a portion of the tip 64 in the axial direction 90 in the internal space of the cover tube 263.

[0091] [Second welding process] In the second welding step, the assembled fluid tube 23, the tubular tip 64, and the cover tube 263 are welded together by heating. In the second welding step, the cover tube 263 is heated from the outside by a heater (not shown). The inner circumferential surface of the heated cover tube 263 is welded to a part of the outer circumferential surface of the tip tip 64 and to a part of the outer circumferential surface of the distal end portion 77 of the fluid tube 23. A part of the outer circumferential surface of the tip tip 64 is welded to a part of the outer circumferential surface of the distal end portion 77 of the fluid tube 23 and to a part of the inner circumferential surface of the distal end portion 77 by heating.

[0092] The distal end 77 of the fluid tube 23 is liquid-tightly sealed by being welded by heating. When the distal end 77 is welded to the cover tube 263, the internal space of the cover tube 263 is crushed, and the distal end 77 is liquid-tightly sealed.

[0093] [Pulling process] After the second welding step, the tip member 61 is naturally cooled. After cooling, the mandrel 81 is pulled out from the tip member 61. The space held by the mandrel 81 becomes the guidewire lumen 62.

[0094] 11, according to the manufacturing method of the ablation catheter of the second modification, the distal end 77 is located inside the opening 294 on the proximal end side of the cover tube 263. The cover tube 263 surrounds the distal end 77 of the fluid tube 23 on the proximal end side.

[0095] [Other variations] In this embodiment, the fluid tube 23 is inserted into the shaft 22, but the fluid tube 23 is not essential. In other words, there is no need to distinguish between an inflow lumen for introducing fluid into the balloon 21 and an outflow lumen for discharging fluid from the balloon 21. In this case, the tip of the shaft 22 protrudes from the distal end of the balloon 21, and the tip of the shaft 22 and the tip tip 64 are connected by a cover tube 63.

[0096] In this embodiment, the internal space of the distal tip 64 defines the guidewire lumen 62, but the internal space does not have to be defined. In this case, the outer peripheral surface of the distal tip 64 and the inner peripheral surface of the cover tube 63 may define the guidewire lumen 62.

[0097] The cover tube 63 may be formed by connecting a plurality of tubes in the axial direction by heat welding. In this case, for example, the cover tube 63 is formed from two tubes, a proximal tube and a distal tube. The cover tube 63 is formed by welding the end faces of the proximal tube and the distal tube facing each other in abutting state, and the internal spaces of these tubes are connected. The proximal tube and the distal tube are welded before the second welding step. It is preferable that the hardness of the distal tube is smaller than that of the proximal tube. This makes it easier for the tip member 61 to follow the curvature of the blood vessel. In addition, the tip member 61 is less likely to damage the blood vessel.

[0098] In addition, the distal end of the cover tube 63 may be located distal to the tip 64 in the axial direction 90 .

[0099] In addition, the proximal end of the tip 64 may protrude beyond the proximal end of the cover tube 63 .

[0100] In addition, in this embodiment, the guidewire lumen 62 is formed only in the tip member 61, but the guidewire lumen may be formed on the proximal end side of the balloon 21. In this case, for example, a guidewire tube extending along the shaft 22 is used on the outside of the shaft 22, and the internal space of the guidewire tube may be used as the guidewire lumen.

[0101] In this embodiment, the housing 53 and the reflector 55 are used, but they may not be used. In this case, for example, the distal ends of the light guiding tube 51 and the optical fiber 52 may be bent so that the end face 57 of the distal end of the optical fiber 52 is oriented perpendicular to the direction intersecting the axis.

[0102] Moreover, the first welding step may be carried out after the second welding step or the third welding step.

[0103] In the assembly process, the distal end 77 of the fluid tube 23 does not have to be cut in advance, and may be cut in a ring shape with the end surface perpendicular to the axis. [Explanation of symbols]

[0104] 11. Ablation catheter 21. Balloon 22 Shaft 23 Fluid tube 52 Optical Fiber 55...Reflective material 61,161...Tip member 62 Guidewire lumen 63,263···Cover tube 64 Tip 67...Aperture 68...Aperture 81...Mandrel 69... Distal end 70...proximal end 90...Axial direction 294...Aperture

Claims

1. A hollow shaft; A balloon provided on the distal end side of the shaft; an optical fiber that is inserted into the shaft and propagates the laser light and emits it to the outside; A tip member provided on the distal end side of the balloon; a tube that is inserted through the shaft and the balloon and protrudes beyond the distal end of the balloon, The tip member is a guidewire lumen opening at the distal end and the proximal end of the tip member; A tip located on the distal end side of the tube; a cover tube connecting the tip and a distal end of the tube; An ablation catheter, wherein the guidewire lumen is at least partially defined by the distal tip.

2. 2. The ablation catheter according to claim 1, wherein a guidewire lumen is formed only in the tip member.

3. The tube has an opening within the balloon, The ablation catheter according to claim 1 or 2, wherein the guidewire lumen opens at a proximal end of the cover tube.

4. The tip protrudes distally beyond the distal end of the cover tube, 4. The ablation catheter according to claim 3, wherein the hardness of the distal tip is less than the hardness of the cover tube.

5. An ablation catheter as described in claim 1, wherein the distal end of the tube is liquid-tight sealed by welding it to the tip member.

6. an assembly process in which the distal tip through which the rod-shaped mandrel is inserted is covered with a cover tube so that the base end of the mandrel protrudes from the proximal end of the cover tube; a heating step of integrating the distal end of the tube inserted into the balloon, the tip, and the cover tube by heating; and a pulling step of pulling the mandrel out from the integrated tube, the distal tip, and the cover tube.

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