JP2022034313A - Ablation catheter and ablation catheter manufacturing method - Google Patents

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

The present invention relates to an ablation catheter that irradiates a laser beam and a method for manufacturing the ablation catheter.

It is known that when nerves located near the adventitia of the renal artery are cauterized, blood pressure decreases in the long term. Such a technique for cauterizing nerves in the renal arteries is referred to as renal artery sympathetic nerve ablation or renal denavation (hereinafter, also simply referred to as "ablation"). Such ablation is expected as a treatment for hypertension. In ablation, an ablation catheter is used (Patent Document 1).

Japanese Unexamined Patent Publication No. 2015-217215

It is said that ablation is preferably applied to the lateral branches of the renal arteries, which are closer to the kidney than near the aorta. Therefore, the ablation catheter is guided to the renal artery by a guide wire to enable more accurate blood vessel selection.

In Patent Document 1, the guide wire tube in which the guide wire lumen is formed is located on the proximal end side of the balloon. Therefore, it is difficult to guide a balloon or the like on the distal end side of the guide wire tube to a relatively small diameter renal artery. Further, when the guide wire tubes are juxtaposed with the shaft, the outer diameter of the shaft may be increased or the flexibility of the shaft may be reduced.

On the other hand, in an ablation catheter, when a guide wire lumen that is inserted into the internal space of a shaft or balloon and opens at the distal end of the catheter is adopted, the tube that separates the guide wire lumen and the optical path of the laser beam overlap in the radial direction. Since the laser beam emitted in the radial direction is blocked by the tube, there is a possibility that ablation cannot be performed accurately. In addition, the outer diameter of the catheter may become large, or the flexibility of the catheter may decrease.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide an ablation catheter having good operability by a guide wire inserted through a guide wire lumen.

(1) The ablation catheter according to the present invention includes a hollow shaft, a balloon provided on the distal end side of the shaft, and an optical fiber inserted through the shaft and propagating laser light to be emitted to the outside. It is provided with a tip member provided on the distal end side of the balloon. The tip member has a guide wire lumen that opens at the distal and proximal ends of the tip member.

Since the guide wire is inserted into the guide wire lumen formed on the tip member provided on the distal end side of the balloon, the tip member follows the guide wire and can easily guide the balloon to the renal artery. Further, since there is no member for partitioning the guide wire lumen in the balloon, the laser beam is not affected and ablation can be performed with high accuracy.

(2) Preferably, the guide wire lumen is formed only on the tip member.

The guide wire can be separated from the ablation catheter only by pulling the guide wire out of the guide wire lumen formed on the tip member of the ablation catheter. Further, the outer diameter of the shaft can be reduced and the shaft can be made flexible.

(3) Preferably, a tube that is inserted through the shaft and the balloon and projects from the distal end of the balloon toward the distal end is further provided. The tube is open in the balloon. The tip member has a tip tip located on the distal end side of the tube, and a cover tube connecting the tip tip and the distal end portion of the tube. The guide wire lumen is at least partially partitioned by the tip and opens at the proximal end of the cover tube.

The configuration of the tip member is simplified, and the tip member easily follows the curvature of the blood vessel.

(4) Preferably, the tip tip projects toward the distal end side of the distal end of the cover tube. The hardness of the tip is smaller than the hardness of the cover tube.

The tip member easily follows the curvature of blood vessels. In addition, the tip member does not easily damage the blood vessel.

(5) The method for manufacturing an ablation catheter according to the present invention is an assembly step in which a tip tip into which a rod-shaped mandrel is inserted is covered with a cover tube, and the base end of the mandrel protrudes from the proximal end of the cover tube. And the heating step of integrating the distal end of the tube inserted into the balloon, the tip tip, and the cover tube by heating, and the tube, the tip tip, and the cover tube integrated. Includes a pull-out process, which pulls out the mandrel.

An ablation catheter having a guide wire lumen formed on the tip member can be easily manufactured.

According to the present invention, it is possible to realize an ablation catheter having good operability by using a guide wire inserted through a guide wire lumen.

FIG. 1 is a diagram showing a configuration of a catheter system 10 including an ablation catheter 11 according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the ablation catheter 11 on the distal end side before the guide wire 80 is removed. FIG. 3 is a cross-sectional view of the ablation catheter 11 on the distal end side after the balloon 21 is inflated. FIG. 4 is a cross-sectional view of the vicinity of the connector portion 26. FIG. 5A is a schematic view showing a state in which the ablation catheter 11 is inserted into the renal artery 91, and FIG. 5B is a schematic view showing a state in which the ablation catheter 11 is inserted into the renal artery 91. FIG. 6 is a flowchart showing a method of manufacturing the ablation catheter 11. FIG. 7 is a schematic cross-sectional view showing a state of being assembled by the assembly process. FIG. 8 is a schematic cross-sectional view showing a state before welding in which the fluid tube 23 and the tip member 61 are combined in the third welding step. FIG. 9 is a cross-sectional view of the ablation catheter 11 according to the first modification of the present invention on the distal end side before the guide wire 80 is removed. FIG. 10 is a schematic cross-sectional view showing a state assembled by the assembly process according to the second modification of the present invention. FIG. 11 is a cross-sectional view of the ablation catheter according to the second modification before the guide wire 80 is removed from the distal end side.

Hereinafter, preferred embodiments of the present invention will be described. Needless to say, the present embodiment is only one embodiment of the present invention, and the embodiments can be changed without changing the gist of the present invention.

[Catheter system 10]
The catheter system 10 is used, for example, to ablate the nerves of the 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 beam generator 14, and a rotating device 15. The catheter system 10 may be used for ablation of heart tissue.

[Ablation catheter 11]
As shown in FIGS. 1, 2 and 3, the ablation catheter 11 has a shaft 22 provided with a balloon 21 on the distal end side. The shaft 22 is a member long in the axial direction 90. The shaft 22 is a tubular body that elastically bends so as to bend with respect to the axial direction 90. The direction in which the shaft 22 in a non-curved state extends is referred to as an axial direction 90 in the present specification. The ablation catheter 11 may be used for catheter ablation (myocardial ablation) for arrhythmia.

As shown in FIGS. 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 inner diameter of the shaft 22 do not necessarily have to be constant with respect to the axial direction 90. The material of the shaft 22 is synthetic resin, stainless steel, or the like, and is not necessarily composed of only one kind of material, and may be composed 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.

In the present embodiment, the proximal end side or the proximal end side means the posterior side (right side in FIG. 1) with respect to the direction in which the ablation catheter 11 is inserted into the blood vessel. The distal end side refers to the anterior side (left side in FIG. 1) with respect to the direction in which the ablation catheter 11 is inserted into the blood vessel.

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 from the internal space. In FIG. 1, a balloon 21 in a contracted state is shown. The fluid flowing through the balloon 21 is not particularly limited, but for example, in the ablation of the renal artery 91, a mixed solution of physiological saline and a contrast medium is used.

The fluid tube 23 penetrates the balloon 21. In the fluid tube 23, the distal end portion 77 projects toward the distal end side from the balloon 21. The fluid tube 23 has openings 71, 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 with respect to the circumferential direction of the axial direction 90. The distal end 77 of the fluid tube 23 protrudes from the balloon 21 of the fluid tube 23, is a part of the distal end side in the axial direction 90, and includes an outer peripheral surface and an 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 toward the distal end side from the balloon 21.

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.

The light guide tube 51 is a tube body that can be elastically bent so as to be curved with respect to the axial direction 90. The distal end of the light guide tube 51 reaches the internal space of the balloon 21, and the proximal end extends outward through the connector portion 26. The light guide tube 51 is movable with respect to the connector portion 26 along the axial direction 90, and is rotatable around the axial direction 90.

The optical fiber 52 is located in the internal space of the light guide tube 51. That is, the optical fiber 52 is inserted through the shaft 22. The end face 57 at the distal end of the optical fiber 52 is orthogonal to the axis. The optical fiber 52 is generated in the laser light generator 14 and propagates the laser light radiated to the base end of the optical fiber 52 toward the distal end side. As the optical fiber 52, a fiber having a refractive index that totally reflects at the wavelength of the laser light is appropriately adopted.

A housing 53 is attached to the distal end of the light guide tube 51. The housing 53 is located in the internal space of the balloon 21. The housing 53 has a tube shape, and the optical fiber 52 is located in the internal space thereof. The housing 53 has an opening 54 that penetrates the peripheral wall. The reflector 55 is located on the distal end side of the opening 54 in the housing 53. In the internal space of the housing 53, the end surface 57 of the optical fiber 52 and the reflector 55 are separated from each other, and the opening 54 is located between the end surface 57 of the optical fiber 52 and the reflector 55.

The reflective material 55 is located in the internal space of the housing 53 so as to face the end surface 57 of the optical fiber 52 and the axial direction 90. The reflective material 55 reflects the laser light emitted from the optical fiber 52 in the internal space of the balloon 21. The reflected laser beam is emitted in a direction orthogonal to the axial direction 90. In the reflective material 55, the reflective surface 56 facing the end surface 57 is inclined so as to have an angle of 45 degrees with respect to the axial direction 90. The reflective surface 56 is exposed to the outside of the housing 53 through the opening 54 of the housing 53. The reflective material 55 is a cylindrical body made of metal, an optical fiber, a resin, or the like. A metal layer is laminated on the reflective surface 56 of the reflective material 55. The metal layer is formed by plating, sputtering, or the like on the surface of the reflective material 55, for example, by nickel, gold, aluminum, chromium, or the like alone or mixed. The direction in which the laser beam reflected by the reflector 55 is emitted may be a direction that intersects the axial direction 90.

The optical fiber 52 and the reflective material 55 are integrated around the axis (axis direction 90) together with the light guide tube 51 while maintaining the positional relationship between the end surface 57 and the reflective surface 56, that is, the separation distance and the angle of the reflective surface 56. It is rotatable and slidable in the axial direction 90. The rotation and slide of the optical fiber 52 and the reflector 55 are controlled by directly or indirectly operating the proximal end side of the light guide tube 51 extending from the connector portion 26. Specifically, the light guide tube 51 is rotated and slid by applying a driving force from the rotating device 15 to the base end side of the light guide tube 51.

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

As shown in FIGS. 2 and 3, the tip member 61 includes a cover tube 63 partially 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. Have.

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 and 95 communicate the internal space and the external space of the cover tube 63. The opening 94 faces the direction in which the cover tube 63 is bent during welding and intersects the axial direction 90. The opening 95 faces in the axial direction 90.

The outer peripheral surface on the proximal end side of the cover tube 63 is welded to the outer peripheral surface or the inner peripheral surface of the distal end portion 77. When the distal end portion 77 is welded to the tip member 61, the opening peripheral edge 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 closed, for example, because the internal space is crushed and the inner peripheral surfaces are welded to each other. The distal end portion 77 may be liquid-tightly closed by welding the outer peripheral surface of the tip member 61 and the inner peripheral surface of the distal end portion 77.

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

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

The tip 64 is formed in a tubular shape, and an internal space separates the guide wire lumen 62. The tip 64 has an opening 67 on the proximal end side. The internal space of the tip tip 64 communicates with the external space through 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 guide wire lumen 62. The opening 67 faces in a direction intersecting the axial direction 90 due to deformation of the tip tip 64 and the cover tube 63 during welding.

The tip 64 has an opening 68 at the distal end. The opening 68 communicates the internal space and the external space of the tip tip 64. The opening 68 faces in the axial direction 90. That is, the opening 68 opens to the distal end surface of the tip member 61. The guide wire lumen 62 is opened at the distal end 69 and the proximal end 70 of the tip member 61 by the opening 67 and the opening 68. The distal end 69 of the tip member 61 points to the distal end face of the tip member 61 facing in the axial direction 90. The proximal end 70 of the tip member 61 is a part of the tip member 61 on the proximal end side from the center in the axial direction 90, and includes an outer peripheral surface and an end surface.

The distal end portion 77, the cover tube 63, and the tip tip 64 shown in FIGS. 2 and 3 are examples of the shape after welding, and the boundary between the distal end portion 77, the cover tube 63, and the tip tip 64 is shown. It was done. The distal end portion 77, the cover tube 63, and the tip tip 64 may be integrated by welding so that their boundaries are absent or ambiguous. Further, the distal end portion 77, the cover tube 63, and the tip tip 64 may be partially mixed. Therefore, the distal end portion 77, the cover tube 63, and the tip tip 64 may not have the configurations shown in FIGS. 2 and 3, and their boundaries may be formed as an ambiguous integral body.

As shown in FIG. 1, a connector portion 26 is provided on the base end side of the shaft 22. The connector portion 26 is a portion held by the practitioner when operating the ablation catheter 11. An optical fiber 52 is inserted through the connector portion 26. The connector portion 26 is provided with a first port 27 and a second port 28 separately from the insertion port of the optical fiber 52.

As shown in FIG. 4, the first port 27 is continuous with the first lumen 24. Through the first port 27, the fluid refluxed 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 refluxed to the balloon 21 flows out of the second lumen 25. Inside the connector portion 26, the first port 27 and the second port 28 are liquidtightly separated by O-rings 73 and 74, respectively. Further, the periphery of the light guide tube 51 is ensured to be liquidtight by the O-ring 75.

[Circuit 12]
The circuit 12 is used to circulate 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. And have.

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

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 configured by connecting a plurality of synthetic resin tubes by joints or the like. The first flow path 32 connects the buffer tank 31 and the first port 27 so that fluid can flow.

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 configured by connecting a plurality of synthetic resin tubes by joints or the like. The second flow path 34 connects the buffer tank 31 and the second port 28 so that fluid can flow. A known joint may be used for the connection between each flow path and each port.

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. As the pressure sensor 33, for example, a diaphragm type pressure sensor is used. The detection signal of the pressure sensor 33 is output to the controller 44.

A check valve 35 is provided in the second flow path 34. The check valve 35 causes the fluid to flow in one direction and stops the flow of the fluid in the other direction by moving the valve provided in the housing by the back pressure of the fluid. The check valve 35 circulates the fluid in the second flow path 34 with the direction in which the fluid flows from the second port 28 toward the buffer tank 31 as one direction. On the other hand, the check valve 35 stops the flow of the fluid from the buffer tank 31 to the second port 28 in the second flow path 34.

[Drive device 13]
The drive device 13 includes 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 constituting the first flow path 32 is set in the pump 41. The pump 41 can be driven in both directions.

As the display 42, for example, a liquid crystal display (abbreviation of Liquid Crystal Display), an organic EL display (abbreviation of Organic Electro-Luminence Display) and the like are adopted.

The input I / F 43 is a user interface that accepts an input operation by the user. Specifically, the input I / F 43 is a film-like touch sensor superimposed on the display 42. Further, the input I / F 43 may be a button provided in the drive device 13. The input I / F 43 accepts a user operation and outputs various signals corresponding to the accepted operation to the controller 44. Examples of the operation signal include expansion of the balloon 21, contraction of the balloon 21, and the like.

The controller 44 has a memory, a CPU, etc. (not shown). A program is set in the controller 44 in advance, and the operation of the pump 41, the operation of the laser light generator 14, and the operation of the rotating device 15 are controlled according to the program.

[Laser light generator 14]
In the laser light generator 14, for example, the light of the excitation source is given to the laser medium, and is transmitted and output by the reflection of the optical resonator. The laser light output from the laser light generator 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 generator 14 is connected to the base end of the optical fiber 52, and the laser light output from the laser light generator 14 irradiates the base end surface of the optical fiber 52.

[Rotating device 15]
The rotating device 15 applies a driving force for rotating and sliding the proximal end side of the light guide tube 51 with respect to the axial direction 90, and a mechanism in which a motor, a slider, or the like is combined can be adopted. The rotating device 15 is not essential, and the light guide tube 51 may be rotated and slid in the axial direction 90 by the practitioner handling the proximal end side of the light guide tube 51.

[How to use the ablation catheter 11]
Hereinafter, an example of how to use the ablation catheter 11 in the catheter system 10 will be shown. As shown in FIG. 5A, the guide wire 80 is sent to a predetermined position in the renal artery 91 on the renal side from the branch 92 in the renal artery 91. In the ablation catheter 11, the guide wire 80 is inserted into the guide wire lumen 62 outside the body. Then, the ablation catheter is sent to a predetermined position in the renal artery 91 in the body along the guide wire 80.

As shown in FIG. 5B, after the ablation catheter 11 is fed to a predetermined position, the guide wire 80 is withdrawn 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 guide tube 51 and the reflective material 55 in the housing 53, so that the laser can be irradiated in the entire circumferential direction around the axis of the shaft 22. After laser irradiation, the balloon 21 is contracted and the ablation catheter 11 is recovered.

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

[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 on the distal end side of the balloon 21 is inserted into the shaft 22 and welded to the outer peripheral surface of the fluid tube 23 protruding from the shaft 22, and the inner peripheral surface on the proximal end side of the balloon 21 is the shaft 22. It is welded to the outer peripheral surface of the distal end.

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

The mandrel 81 maintains the internal space of the tip tip 64 and the state in which the opening 67 on the proximal end side and the opening 68 on the distal end side are connected during welding. The mandrel 81 is, for example, a metal rod having a circular vertical cross section.

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

The tip of the mandrel 81 protrudes from the opening 68 of the tip tip 64, and the base end protrudes from the opening 67 of the tip tip 64. The timing at which the mandrel 81 is inserted into the tip tip 64 may be after the tip tip 64 is inserted into the cover tube 63.

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

[Second welding process]
The second welding step is a step of welding the assembled tubular tip tip 64 and the cover tube 63 by heating to integrate them. In the second welding step, the cover tube 63 is heated from the outside by a heater (not shown). The inner peripheral surface of the heated cover tube 63 is welded to the outer peripheral surface of the tip tip 64. The welded cover tube 63 forms part of the proximal end 70.

[Third welding process]
The third welding step is a step of welding the fluid tube 23 into which the balloon 21 is welded and the tip member 61 welded in the second welding step by heating to integrate them. The distal end 77 of the fluid tube 23 is pre-cut so that the end face is not orthogonal to the axis. As shown in FIG. 8, the distal end portion 77 is attached to the tip member 61 so that the direction of protrusion from the balloon 21 is along the continuous direction of the mandrel 81. At this time, a part of the outer peripheral surface of the distal end portion 77 comes into contact with a part of the outer peripheral surface of the tip member 61. Further, the end surface of the distal end portion 77 is directed toward the outer peripheral surface side of the tip member 61.

In the third step, the distal end portion 77 is heated from the outside by a heater (not shown) in a state where the fluid tube 23 and the tip member 61 are combined. By heating, heat is transferred in the order of the distal end portion 77, the cover tube 63, and the tip tip 64. In the distal end portion 77, the opening peripheral edge 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 by heating, and for example, the internal space of the distal end portion 77 is crushed and far away. The inner peripheral surfaces of the position end portion 77 are welded to each other, so that the inner peripheral surfaces are closed in a liquid-tight manner. The distal end portion 77 may be closed liquid-tightly by welding the outer peripheral surface of the tip member 61 and the inner peripheral surface of the distal end portion 77. The second welding step and the third welding step are examples of the heating step.

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

[Action and effect of this embodiment]
In the present embodiment, since the guide wire 80 is inserted into the guide wire lumen 62 formed in the tip member 61 provided on the distal end side of the balloon 21, the tip member 61 follows the guide wire 80 and the balloon Can be easily guided to the renal artery.

Further, since there is no member for partitioning the guide wire lumen 62 in the balloon 21, the laser beam is not affected and ablation can be performed with high accuracy.

Further, since the guide wire lumen 62 is formed only on the tip member 61, the guide wire 80 is formed from the ablation catheter 11 only by pulling out the guide wire 80 from the guide wire lumen 62 formed on the tip member 61 of the ablation catheter 11. Can be released. In addition, the outer diameter of the shaft on the proximal end side of the balloon can be reduced, and the shaft can be made flexible.

Further, since the guide wire lumen is not 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 vertical cross section of the shaft 22 or the balloon 21. As a result, the distance until the emitted laser light reaches the blood vessel can be made constant.

Further, since the tip member 61 is composed of a tip tip 64 located on the distal end side of the fluid tube 23 and a cover tube 63 connecting the tip tip 64 and the distal end of the fluid tube 23, the tip member 61 is a tip. The configuration of the member 61 is simplified, and the tip member 61 easily follows the curvature of the blood vessel.

Further, the hardness of the cover tube 63 is smaller than the hardness of the fluid tube 23 and larger than the hardness of the tip tip 64. Further, a part of the inner peripheral surface of the distal end portion 77 of the fluid tube 23 is welded to a part of the outer peripheral surface of the cover tube 63. Further, the cover tube 63 surrounds the tip tip 64. By reducing the hardness difference between the fluid tube 23 and the tip tip 64 in this way, the tip tip 64 is prevented from breaking and the tensile strength of the tip member 61 is improved.

Further, according to the method for manufacturing the ablation catheter 11 of the present embodiment, the ablation catheter 11 in which the guide wire lumen 62 is formed on the tip member 61 can be easily manufactured.

Further, in the third welding step, the distal end portion 77 is located on the outside of the tip member 61, and the heat generated by heating is transferred in the order of the distal end portion 77, the cover tube 63, and the tip tip 64, so that the operator is far away. Welding between the position end portion 77 and the tip member 61 can be visually confirmed, and it is possible to prevent the welding work from being completed before the welding between the distal end portion 77 and the tip member 61 is completed.

Further, by welding the balloon 21 to the fluid tube 23 and the shaft 22 not after the second welding step but before the assembly step, the balloon 21 is prevented from being welded to the outer peripheral surface of the cover tube 63, and the balloon 21 is prevented from being welded. Leakage from the distal end side of the is prevented.

Further, since the distal end portion 77 of the fluid tube 23 is cut off, in the third welding step, the distal end portion 77 protrudes from the balloon 21 along the continuous direction of the mandrel 81. In the state, the distal end portion 77 can be attached to the tip member 61 and welded. As a result, it is not necessary to adjust the angle in the direction in which the distal end portion 77 protrudes from the balloon 21 with respect to the direction in which the tubular tip member 61 extends, and the workability of welding is good.

Further, the diameter of the guide wire lumen can be easily changed by changing the diameter of the mandrel 81 without changing the diameter of the shaft 22.

[Modification 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 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.

As shown in FIG. 9, the tip member 161 includes a cover tube 163 that partially closes 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. Has. The cover tube 163 is made of resin. The hardness of the cover tube 163 is higher than the hardness of the tip tip 64, for example.

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 and 195 communicate the internal space and the external space of the cover tube 163. The opening 194 faces the direction in which the cover tube 163 is bent during welding and intersects the axial direction 90. The opening 195 faces in the axial direction 90.

The outer peripheral surface of the cover tube 163 is welded to the inner peripheral surface of the distal end portion 77 of the fluid tube 23. The cover tube 163 surrounds the base end of the tip tip 64. The inner peripheral surface of the cover tube 163 is welded to the outer peripheral surface of the proximal end of the tubular tip tip 64. The distal end of the cover tube 163 is located axially 90 at the proximal end side of the distal end of the tip tip 64, with the distal end 69 of the tip tip 64 protruding from the distal end of the cover tube 163. There is. The hardness of the tip tip 64 is smaller than the hardness of the cover tube 163. The opening 67 of the tip tip 64 is located inside the opening 194 of the cover tube 163. The opening 68 of the tip tip 64 is located at the distal end side of the opening 195 of the cover tube 163 in the axial direction 90.

[Action and effect of variant 1]
The tip tip 64 projects toward the distal end side from the distal end of the cover tube 163, and the hardness of the tip tip 64 is smaller than the hardness of the cover tube 163, so that the tip member 61 follows the curvature of the blood vessel or the like. Cheap. In addition, the tip member 61 does not easily damage the blood vessel. Further, since the tip 64 has a smaller outer diameter than the cover tube 163, the tip of the ablation catheter can be made smaller in diameter.

[Modification 2]
In the above embodiment, the distal end portion 77 of the fluid tube 23 is welded to the tip member 61 in the third welding step, but may be welded to the tip member 61 in the second welding step. In the second modification, the distal end portion 77 of the fluid tube 23 is welded to the cover tube 263 and the tip tip 64 in the second welding step, and an example in which the third welding step is omitted will be described. 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 modified example is an example of the heating step.

The method for manufacturing an ablation catheter according to the second modification includes a first welding step, an assembling step, a second welding step, and a drawing step.

[Assembly process]
As shown in FIG. 10, in the assembly process, the fluid tube 23 to which the balloon 21 is welded, the tip tip 64, the cover tube 263, and the mandrel 81 are assembled. The proximal end of the cover tube 263 is pre-flared. Flaring is performed by a known method. Since the proximal end of the cover tube 263 is flared, the workability of inserting the fluid tube 23 and the tip 64 into the cover tube 263 is good.

The mandrel 81 is inserted into the internal space of the tip tip 64. The tip tip 64 is inserted into the cover tube 263. Also, the distal end 77 of the fluid tube 23 is inserted into the cover tube 263.

The tip of the mandrel 81 protrudes from the opening 68 of the tip tip 64, and the base end protrudes from the opening 67 of the tip tip 64. The timing at which the mandrel 81 is inserted into the tip tip 64 may be after the tip tip 64 and the distal end portion 77 of the fluid tube 23 are inserted into the cover tube 263.

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

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

The distal end 77 of the fluid tube 23 is hermetically closed by welding by heating. When the distal end portion 77 is welded to the cover tube 263, the internal space of the cover tube 263 is crushed and the distal end portion 77 is liquid-tightly closed.

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

As shown in FIG. 11, according to the method for manufacturing the ablation catheter of the second modification, the distal end portion 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.

[Other variants]
In the present embodiment, the fluid tube 23 is inserted in the shaft 22, but the fluid tube 23 is not essential. That is, it is not necessary to distinguish between the inflow lumen that causes the fluid to flow into the balloon 21 and the outflow lumen that causes the fluid to flow out of 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 the cover tube 63.

Further, in the present embodiment, the internal space of the tip tip 64 partitions the guide wire lumen 62, but the internal space may not be partitioned. At this time, the outer peripheral surface of the tip tip 64 and the inner peripheral surface of the cover tube 63 may partition the guide wire lumen 62.

Further, the cover tube 63 may be formed by connecting a plurality of tubes by heat welding in the axial direction. At this time, for example, the cover tube 63 is formed of two tubes, a tube on the proximal end side and a tube on the distal end side. The cover tube 63 is welded in a state where the end surface of the tube on the proximal end side and the end surface of the tube on the distal end side are in contact with each other, and the internal space between these tubes is formed to be continuous. The tube on the proximal end side and the tube on the distal end side are welded before the second welding step. The hardness of the tube on the distal end side is preferably smaller than that on the tube on the proximal end side. As a result, the tip member 61 can easily follow the curvature of the blood vessel. In addition, the tip member 61 does not easily damage the blood vessel.

Further, the distal end of the cover tube 63 may be positioned at the distal end side of the tip tip 64 in the axial direction 90.

Further, the proximal end of the tip tip 64 may protrude from the proximal end of the cover tube 63.

Further, in the present embodiment, the guide wire lumen 62 is formed only on the tip member 61, but the guide wire lumen 62 may be formed on the proximal end side of the balloon 21. At this time, for example, a guide wire tube extending along the shaft 22 may be used on the outside of the shaft 22, and the internal space of the guide wire tube may be a guide wire lumen.

Further, in the present embodiment, the housing 53 and the reflective material 55 are used, but these may not be used. At this time, for example, the distal ends of the light guide tube 51 and the optical fiber 52 may be bent so that the end surface 57 of the distal end of the optical fiber 52 is oriented perpendicular to the direction intersecting the axis.

Further, the first welding step may be carried out after the second welding step or the third welding step.

Further, in the assembly step, the distal end portion 77 of the fluid tube 23 may not be cut in advance, and may be cut into round slices whose end face is orthogonal to the axis.

11 ... Ablation catheter 21 ... Balloon 22 ... Shaft 23 ... Fluid tube 52 ... Optical fiber 55 ... Reflective material 61, 161 ... Tip member 62 ... Guide wire lumen 63, 263 ... Cover tube 64 ... Tip tip 67 ... Opening 68 ... Opening 81 ... Mandrel 69 ... Distal end 70 ... Proximal end 90 ... Axial direction 294 ... Opening

Claims (5)

With a hollow shaft,
The balloon provided on the distal end side of the shaft and
An optical fiber that is inserted through the shaft and propagates the laser beam to the outside,
It is equipped with a tip member provided on the distal end side of the balloon.
The tip member is an ablation catheter having a guide wire lumen that opens at the distal end and the proximal end of the tip member. The ablation catheter according to claim 1, wherein the guide wire lumen is formed only on the tip member. It further comprises a tube that is inserted through the shaft and the balloon and projects from the distal end of the balloon toward the distal end.
The tube is open in the balloon and
The above tip member
With the tip tip located on the distal end side from the above tube,
It has a cover tube that connects the tip and the distal end of the tube.
The ablation catheter according to claim 1 or 2, wherein the guide wire lumen is at least partially partitioned by the tip and is opened at the proximal end of the cover tube. The tip tip protrudes toward the distal end side of the distal end of the cover tube.
The ablation catheter according to claim 3, wherein the hardness of the tip is smaller than the hardness of the cover tube. An assembly process in which the tip tip into which a 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 that integrates the distal end of the tube inserted into the balloon, the tip tip, and the cover tube by heating.
A method for manufacturing an ablation catheter, comprising a drawing step of pulling out the mandrel from the integrated tube, the tip tip, and the cover tube.

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