Medical device and shunt formation method

Abstract

Provided are a medical device and a shunt formation method with which it is possible to suppress the propagation of heat generated by cauterization to the blood. The medical device 10 is provided with an expanding body 21, a shaft part 20 and an electrode part 22. The expanding body 21 has a recess 51 which defines a receiving space 51b that can receive biological tissue. A base-side protruding part 52 of the recess 51 has a first surface 60 facing the receiving space 51b, and a second surface 61 on the reverse side from the first surface 60. A tip-side protruding part 53 of the recess 51 has a third surface 62 facing the receiving space 51b, and a fourth surface 63 on the reverse side from the third surface 62. The base-side protruding part 52 is an electrode arrangement area where the electrode part 22 is arranged, and the tip-side protruding part 53 is a reverse-surface part on the reverse side from the electrode part 22. The expanding body 21 at least has a heat insulation layer 71 on the third surface 62 or the fourth surface 63 so as to be opposite the electrode part 22 with the receiving space 51b therebetween.

Description

[Technical Field]

[0001] The present invention relates to a medical device for applying energy to living tissue and a method for forming a shunt. [Background technology]

[0002] A medical device known in the art uses an electrode placed in an expandable body that expands and contracts within the body, and performs ablation treatment by cauterizing biological tissue with high-frequency current from the electrode. One known ablation treatment is atrial septal shunt therapy. Shunt therapy creates a shunt (puncture hole) in the atrial septum to provide an escape route for elevated atrial pressure in patients with heart failure, thereby alleviating the symptoms of heart failure. In shunt therapy, the atrial septum is accessed via a transvenous approach, and a puncture hole of the desired size is created.

[0003] In medical devices that perform ablation treatment, current flows from the electrode portion to biological tissue, causing the biological tissue or the vicinity of the electrode portion of the medical device to become hot. This can lead to complications such as steam popping or the formation of blood clots. The medical device shown in Patent Document 1 has an ablation probe configured with a heating element disposed within a cap, and is provided with a heat insulating structure that reduces heat conduction from the heating element to part of the outer surface of the ablation probe. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-112772 Summary of the Invention [Problem to be solved by the invention]

[0005] Some medical devices that perform ablation, such as the medical device used for shunt treatment, have a heat-generating portion directly exposed to the outside. Furthermore, during ablation, not only the heat-generating portion, such as the electrode, but also the biological tissue to which energy is applied may become hot. Therefore, in medical devices with exposed heat-generating portions, it is necessary to suppress the heat from the heat-generating portion and the biological tissue heated thereby from propagating to the blood.

[0006] The present invention has been made to solve the above-mentioned problems, and aims to provide a medical device and a shunt formation method that can suppress the propagation of heat generated by cauterization to the blood. [Means for solving the problem]

[0007] The medical device according to the present invention, which achieves the above object, comprises an expandable body that can be expanded and contracted in a radial direction, a long shaft portion having a distal end portion including a base end fixing portion to which the base end of the expandable body is fixed, and a catheter provided along the expandable body. and applying energy to the biological tissue to maintain the size of the pores formed in the biological tissue. and an electrode portion configured to receive biological tissue, the expandable body having a recess that recesses radially inward when the expandable body is expanded and defines a receiving space capable of receiving biological tissue, the recess having a bottom portion located at the innermost radial position, a base-side upright portion extending radially outward from a base end of the bottom portion, and a tip-side upright portion extending radially outward from a tip end of the bottom portion, the base-side upright portion having a first surface facing the receiving space and a second surface opposite to the first surface, the tip-side upright portion having a third surface facing the receiving space and a fourth surface opposite to the third surface, one of the base-side upright portion and the tip-side upright portion having a second surface facing the receiving space. and does not face the second surface and the fourth surface. the other of the base-side standing portion and the tip-side standing portion is an opposing surface portion opposing the electrode portion, and the expandable body has a heat insulating layer on at least one of the first surface, the second surface, the third surface, and the fourth surface so as to face the electrode portion across the receiving space. The expansion body has a frame formed of metal that defines the shape of the expansion body and includes the electrode placement section, and the heat insulating layer that is provided on a surface of the frame, and the heat insulating layer is provided on at least the first surface and the third surface so as to sandwich the receiving space while separating the electrode section from the electrode placement section of the frame. . [Effects of the Invention]

[0010] The medical device configured as described above has an insulating layer on the surface facing the electrode portion across the receiving space, making it difficult for heat from biological tissue heated by the energy applied from the electrode portion, or from the heat-generating portion itself, such as the electrode portion, to be transmitted to the blood, thereby reducing the risk of thrombus formation.

[0011] Furthermore, the medical device configured as described above covers a portion of the surface of the recess facing the receiving space and the opposite surface with an insulating cover portion, at least in the vicinity of the electrode portion, thereby making it difficult for heat from the biological tissue heated by the energy applied from the electrode portion to be transmitted to the blood, thereby reducing the risk of thrombus formation.

[0012] Furthermore, in the shunt formation method configured as described above, when voltage is applied to the electrode portion, the recess of the expansion body is insulated by an insulating layer or insulating cover portion, making it difficult for heat associated with cauterization to propagate to the blood, thereby reducing the risk of thrombus formation.

[0013] The expandable body may have a frame that defines the shape of the expandable body, and the heat insulating layer provided on a surface of the frame, thereby making it possible to provide the heat insulating layer while ensuring flexibility of the expandable body.

[0014] The heat insulating layer may be provided over substantially the entire surfaces of the frame on the inner side and the outer side in the expansion direction, thereby improving the heat insulating properties of the expandable body and reliably reducing the propagation of heat associated with cauterization.

[0015] The heat insulating layers may be provided on two or more of the first surface, the second surface, the third surface, and the fourth surface so as to sandwich the receiving space, thereby reducing the propagation of heat caused by cauterization on both sides of the recess.

[0016] The heat insulating layer may be provided on an inner surface or an outer surface of the bottom in the expansion direction, thereby reducing heat propagation at the bottom of the recess.

[0017] The expansion body may have a tube that covers the frame and functions as the heat insulating layer, whereby the heat insulating layer can be easily formed by simply attaching the tube to the frame.

[0018] The expandable body may have a frame that defines the shape of the expandable body, and the frame may have a heat insulating member that has the heat insulating layer at least in the region of the recess, thereby making it possible to easily form the heat insulating layer by fixing the heat insulating member to the frame.

[0019] One of the base-side upright portion and the tip-side upright portion may be an electrode placement portion on which the electrode portion is placed so as to face the receiving space, and the other of the base-side upright portion and the tip-side upright portion may be an opposing surface portion facing the electrode portion, and the heat-insulating cover portion may be provided on the surface of the opposing surface portion opposite the surface facing the receiving space. This prevents blood from coming into contact with the opposing surface portion, thereby reliably reducing the propagation of heat generated during cauterization.

[0020] The expandable body may have a frame that defines the shape of the expandable body, and the medical device may further include a second expandable body that has the insulating cover part and is radially expandable and contractible on the inside of the frame in the expansion direction, and the insulating cover part may cover at least the surface of the recess of the frame opposite to the surface facing the receiving space, whereby the second expandable body also expands as the expandable body expands, and the surface of the recess opposite to the surface facing the receiving space can be covered by the insulating cover part.

[0021] The second expansion body may have a second frame that defines the shape of the second expansion body, and the heat insulating cover portion disposed on at least a part of the second frame, thereby making it possible to provide the heat insulating cover portion while ensuring flexibility of the second expansion body.

[0022] The second expandable body may have a mesh made of a woven number of wires and the insulating cover portion disposed on at least a part of the mesh. The mesh can flexibly deform to fit the shape of the expandable body, so that the insulating cover portion can be brought into closer contact with the expandable body, thereby improving the insulating properties.

[0023] The second expandable body may have a radially expandable balloon that functions as the heat insulating cover. This allows the inside of the expandable body to be covered with the balloon, more reliably preventing the surface of the frame recess opposite to the surface facing the receiving space from coming into contact with blood and more reliably reducing heat propagation. [Brief explanation of the drawings]

[0024] [Figure 1] 1 is a front view showing the overall configuration of a medical device according to an embodiment. [Figure 2] FIG. 10 is an enlarged perspective view of the vicinity of the expansion body. [Figure 3] FIG. [Figure 4] FIG. 10 is a front view showing one of the wire rod portions stretched flat. [Figure 5] FIG. [Figure 6] FIG. 10 is a diagram showing the expandable body housed in a storage sheath. [Figure 7] FIG. 10 is an explanatory diagram showing a state in which an expandable body is placed in the atrial septum, with the medical device shown in a front view and the biological tissue shown in a cross-sectional view. [Figure 8] FIG. 8 is an enlarged view of the vicinity of the expandable body in FIG. 7. [Figure 9] 9 is an explanatory view showing a state in which the expandable body is expanded in diameter at the atrial septum from the state shown in FIG. 8. FIG. [Figure 10] FIG. 10 is an enlarged front view of the vicinity of an expandable body according to a first modified example. [Figure 11] FIG. 10 is an enlarged cross-sectional view of the vicinity of a recess of an expandable body according to a second modified example. [Figure 12]12(a) and 12(b) are an exploded view and a front view, respectively, of one of the wire parts of the expandable body according to the third modified example, which is flattened out. [Figure 13] FIG. 11 is an enlarged cross-sectional view of the vicinity of a recess of an expandable body according to a fourth modified example. [Figure 14] FIG. 11 is an exploded view of the rear side of the expandable body according to the fourth modified example, in which one of the wire parts is stretched flat. [Figure 15] FIG. 13 is an enlarged cross-sectional view of the vicinity of a recess of an expansion body according to a fifth modified example. [Figure 16] FIG. 13 is an enlarged cross-sectional view of the vicinity of an electrode portion of an expansion body according to a fifth modified example. [Figure 17] FIG. 13 is an enlarged cross-sectional view of the vicinity of the electrode portion of the expansion body according to the sixth modification. [Figure 18] 18(a) and 18(b) are a front view and a rear view, respectively, of one of the wire parts of the expandable body according to the seventh modified example, which is stretched flat. [Figure 19] FIG. 13 is an enlarged cross-sectional view of the vicinity of a recess of an expandable body according to a seventh modified example. [Figure 20] FIG. 10 is an enlarged view of the vicinity of an expandable body of a medical device according to a first modified example. [Figure 21] FIG. 10 is a front view of the second frame of the second expansion body stretched out flat. [Figure 22] FIG. 10 is an enlarged view of the vicinity of the expandable body in a case where the electrode portion of the medical device according to the first modification is provided at the bottom of the recess. [Figure 23] FIG. 11 is a front view of a second expansion body provided inside the expansion body in a medical device according to a second modification. [Figure 24] FIG. 10 is an enlarged view of the vicinity of an expandable body of a medical device according to a second modification. [Figure 25] FIG. 11 is a front view of a second expansion body provided inside the expansion body in a medical device according to a third modification. [Figure 26] FIG. 11 is an enlarged view of the vicinity of an expandable body of a medical device according to a third modification. [Figure 27] FIG. 10 is an enlarged view of the vicinity of an expansion body having a second expansion body according to a modified example. [Figure 28] FIG. 13 is an enlarged view of the vicinity of an expandable body according to an eighth modified example. [Figure 29] FIG. 13 is an enlarged view of the vicinity of an expandable body according to a ninth modified example. DETAILED DESCRIPTION OF THE INVENTION

[0025] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the dimensional proportions in the drawings may be exaggerated for convenience of explanation and may differ from the actual proportions. In addition, in this specification, the side of the medical device 10 that is inserted into a body cavity will be referred to as the "distal end" or "distal side," and the side that is operated by the operator will be referred to as the "proximal end" or "proximal side."

[0026] The medical device in the following embodiments is configured to expand a puncture hole Hh formed in the atrial septum HA of a patient's heart H, and to perform a maintenance procedure to maintain the expanded puncture hole Hh at that size.

[0027] 1, the medical device 10 of this embodiment has a long shaft portion 20, an expansion body 21 provided at the distal end of the shaft portion 20, and an operation portion 23 provided at the proximal end of the shaft portion 20. The expansion body 21 is provided with an electrode portion 22, which is an energy transmission element for performing the maintenance treatment described above.

[0028] The shaft portion 20 has a distal portion 30 including a base end fixing portion 31 to which the base end of the expandable body 21 is fixed, and a distal end fixing portion 33 to which the distal end of the expandable body 21 is fixed. The distal portion 30 of the shaft portion 20 has a shaft extension portion 32 extending from the base end fixing portion 31 into the expandable body 21. The shaft portion 20 has a storage sheath 25 provided on the outermost periphery. The expandable body 21 is movable forward and backward in the axial direction relative to the storage sheath 25. The storage sheath 25 can store the expandable body 21 inside when it is moved toward the distal end of the shaft portion 20. The expandable body 21 can be exposed by moving the storage sheath 25 toward the base end from a state in which the expandable body 21 is stored.

[0029] The shaft portion 20 has a traction shaft 26. The traction shaft 26 is provided from the base end of the shaft portion 20 to the shaft extension portion 32, and its tip end is fixed to a tip member 35. The base end of the traction shaft 26 is led out toward the base end side from the operation portion 23.

[0030] The tip member 35, to which the tip end of the traction shaft 26 is fixed, does not have to be fixed to the expandable body 21. This allows the tip member 35 to pull the expandable body 21 in the compression direction. Furthermore, when storing the expandable body 21 in the storage sheath 25, moving the tip member 35 away from the expandable body 21 toward the tip side facilitates movement of the expandable body 21 in the extension direction, improving storage ease.

[0031] The operation unit 23 has a housing 40 that is held by the surgeon, an operation dial 41 that can be rotated by the surgeon, and a conversion mechanism 42 that operates in conjunction with the rotation of the operation dial 41. The traction shaft 26 is held by the conversion mechanism 42 inside the operation unit 23. The conversion mechanism 42 can move the held traction shaft 26 forward and backward along the axial direction in accordance with the rotation of the operation dial 41. As the conversion mechanism 42, for example, a rack and pinion mechanism can be used.

[0032] The expandable body 21 will be described in more detail. As shown in FIGS. 2 and 3, the expandable body 21 has multiple wire portions 50 arranged in the circumferential direction. In this embodiment, four wire portions 50 are arranged in the circumferential direction. Each wire portion 50 is expandable and contractible in the radial direction. The base end of each wire portion 50 extends from the base end fixing portion 31 toward the distal end. The distal end of each wire portion 50 extends from the base end of the distal end member 35 toward the proximal end. The wire portion 50 is inclined so that it becomes larger in the radial direction from both axial ends toward the center. Furthermore, the wire portion 50 has a recess 51 at the axial center that is recessed radially inward of the expandable body 21. The radially innermost portion of the recess 51 is a bottom 51a. The recess 51 defines a receiving space 51b that can receive biological tissue when the expandable body 21 is expanded.

[0033] The recess 51 has a base-side upright portion 52 extending radially outward from the base end of the bottom portion 51a, and a tip-side upright portion 53 extending radially outward from the tip of the bottom portion 51a. The tip-side upright portion 53 has a slit-shaped central portion in the width direction, and has outer edge portions 55 on both sides and a back support portion 56 in the center.

[0034] 4, the wire portion 50 has through holes 57 on both sides in the extending direction of the portion that becomes the bottom portion 51a. A space 58 is formed between the outer edge portions 55 on both sides, and a back support portion 56 is provided so as to protrude into the space 58.

[0035] The proximal upright portion 52 disposed in the recess 51 has a first surface 60 facing the receiving space 51b and a second surface 61 opposite the first surface 60. The proximal upright portion 52 is an electrode disposition portion where the electrode portion 22 is disposed. The distal upright portion 53 of the recess 51 is an opposing surface portion that faces the electrode portion 22, and has a third surface 62 facing the receiving space 51b and a fourth surface 63 opposite the third surface 62.

[0036] 5, the wire portion 50 has a heat insulating layer 71 on the surface of a metal frame 70 that defines the shape of the expandable body 21, and further has a biocompatible coating 72 on the surface of the heat insulating layer 71. The heat insulating layer 71 is provided on at least one of the opposing surfaces that face the electrode placement portion where the electrode portion 22 is disposed. In this embodiment, the heat insulating layer 71 and the biocompatible coating 72 are provided over substantially the entire surfaces of the frame 70 on the inner side in the expansion direction and the outer side in the expansion direction, so that the first and second surfaces 60 and 61 of the electrode placement portion and the third and fourth surfaces 62 and 63 of the opposing surface portion all have the heat insulating layer 71.

[0037] The frame 70 can be made of a metal material. Examples of such metal materials include titanium alloys (Ti-Ni, Ti-Pd, Ti-Nb-Sn, etc.), copper alloys, stainless steel, β-titanium steel, and Co-Cr alloys. It is preferable to use alloys with spring properties, such as nickel-titanium alloys. However, the material of the frame 70 is not limited to these, and other materials may also be used.

[0038] The heat insulating layer 71 can be made of a resin or foamed plastic with low thermal conductivity. Examples of resin or foamed plastic that can be used include polyether ether ketone (PEEK), polyimide, Pebax, epoxy resin, polytetrafluoroethylene resin (PTFE), and polyurethane. The biocompatible coating 72 can be made of polymethoxyethyl acrylate (PMEA) or the like. Materials other than these may also be used for the heat insulating layer 71 and the biocompatible coating 72.

[0039] The wire portion 50 forming the expandable body 21 has, for example, a flat plate shape cut out from a cylinder. The wire forming the expandable body 21 can have a thickness of 50 to 500 μm and a width of 0.3 to 2.0 mm. However, the wire portion 50 may have dimensions outside these ranges. The wire portion 50 may also have a circular cross-sectional shape or other cross-sectional shapes.

[0040] The electrode portion 22 is provided along the proximal upright portion 52, so when the recessed portion 51 is placed on the atrial septum HA, energy from the electrode portion 22 is transmitted to the atrial septum HA from the right atrium side.

[0041] The electrode unit 22 is configured, for example, as a bipolar electrode that receives electrical energy from an external energy supply device (not shown). In this case, electricity is passed between the electrode units 22 arranged in each wire unit 50. The electrode units 22 and the energy supply device are connected by a conductor (not shown) covered with an insulating coating material. The conductor is led out via the shaft unit 20 and the operating unit 23 and connected to the energy supply device.

[0042] Alternatively, the electrode unit 22 may be configured as a monopolar electrode. In this case, electricity is passed between the electrode unit 22 and a return electrode plate prepared outside the body. Alternatively, a heat generating element (electrode chip) that receives high-frequency electrical energy from an energy supply device and generates heat may be used instead of the electrode unit 22. In this case, electricity is passed between the heat generating elements disposed in each wire unit 50. Furthermore, the electrode unit 22 may be configured using an energy transfer element capable of applying energy to the puncture hole Hh, such as microwave energy, ultrasonic energy, coherent light such as a laser, a heated fluid, a cooled fluid, a device that exerts a heating or cooling effect using a chemical medium, a device that generates frictional heat, a heater equipped with an electric wire, etc., and the specific form is not particularly limited.

[0043] The shaft portion 20 is preferably formed from a material having a certain degree of flexibility, such as polyolefins such as polyethylene, polypropylene, polybutene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ionomer, or a mixture of two or more of these, soft polyvinyl chloride resin, polyamide, polyamide elastomer, polyester, polyester elastomer, polyurethane, fluororesins such as polytetrafluoroethylene, polyimide, PEEK, silicone rubber, and latex rubber.

[0044] The traction shaft 26 can be formed by, for example, covering a long wire made of a superelastic alloy such as a nickel-titanium alloy or a copper-zinc alloy, a metal material such as stainless steel, or a resin material with relatively high rigidity with a resin material such as polyvinyl chloride, polyethylene, polypropylene, or an ethylene-propylene copolymer.

[0045] The tip member 35 can be formed from, for example, a polymeric material such as polyolefin, polyvinyl chloride, polyamide, polyamide elastomer, polyurethane, polyurethane elastomer, polyimide, fluororesin, or a mixture of these, or a multi-layer tube made of two or more types of polymeric materials.

[0046] The expandable body 21 housed in the housing sheath 25 is in a radially contracted state as shown in Fig. 6. The expandable body 21 moves in the axial direction relative to the housing sheath 25 and is exposed to the outside of the housing sheath 25, thereby expanding the expandable body 21 as shown in Fig. 3.

[0047] In this embodiment, four wire portions 50 are provided in the circumferential direction, and four electrode portions 22 are also provided, but more wire portions 50 and electrode portions 22 each having a recess 51 may be provided. The same applies to modified examples described later.

[0048] Furthermore, in this embodiment, the electrode portion 22 is provided on the base-side standing portion 52, but some or all of the electrode portion 22 may be provided on the tip-side standing portion 53. In this case, the tip-side standing portion 53 serves as the electrode placement portion, the base-side standing portion 52 serves as the opposing surface portion, and a heat insulating layer 71 is provided on at least the first surface 60 or the second surface 61 that faces the electrode portion 22 across the receptive space 51b. The same applies to modified examples described below in which a heat insulating layer is provided.

[0049] A treatment method using the medical device 10 will be described. The treatment method of this embodiment is performed on a patient suffering from heart failure (left ventricular failure). More specifically, as shown in Fig. 7, this is a treatment method performed on a patient suffering from chronic heart failure in which the blood pressure of the left atrium HLa increases due to hypertrophy of the myocardium of the left ventricle of the heart H and increased stiffness.

[0050] The treatment method of this embodiment includes the steps of: forming a puncture hole Hh in the atrial septum HA (S1); placing an expandable body 21 in the puncture hole Hh (S2); expanding the diameter of the puncture hole Hh using the expandable body 21 (S3); checking the hemodynamics near the puncture hole Hh (S4); performing maintenance treatment to maintain the size of the puncture hole Hh (S5); and checking the hemodynamics near the puncture hole Hh after the maintenance treatment has been performed (S6).

[0051] When forming the puncture hole Hh, the surgeon delivers an introducer 210, which is a combination of a guiding sheath and a dilator, to the vicinity of the interatrial septum HA. The introducer 210 can be delivered to the right atrium HRa, for example, via the inferior vena cava IV. The introducer can be delivered using a guidewire 11. The surgeon can insert the guidewire 11 into the dilator and deliver the introducer along the guidewire 11. The insertion of the introducer and the guidewire 11 into the living body can be performed by a known method, such as using an introducer for introducing blood vessels.

[0052] In step S1, the surgeon passes a puncture device (not shown) from the right atrium HRa side toward the left atrium HLa side to form a puncture hole Hh. As the puncture device, for example, a device such as a wire with a sharp tip can be used. The puncture device is inserted through the dilator and delivered to the atrial septum HA. After the guide wire 11 is removed from the dilator, the puncture device can be delivered to the atrial septum HA in place of the guide wire 11.

[0053] In step S2, first, the medical device 10 is delivered to the vicinity of the atrial septum HA along the pre-inserted guide wire 11. At this time, the distal end of the medical device 10 penetrates the atrial septum HA and reaches the left atrium HLa. Furthermore, when the medical device 10 is inserted, the expandable body 21 is housed in the housing sheath 25.

[0054] 8, the housing sheath 25 is moved toward the proximal end to expose the expandable body 21. This causes the diameter of the expandable body 21 to expand, and the recess 51 is positioned in the puncture hole Hh in the atrial septum HA, and the receiving space 51b receives the biological tissue surrounding the puncture hole Hh.

[0055] In step S3, with the receiving space 51b receiving the biological tissue, the surgeon operates the operating unit 23 to move the traction shaft 26 toward the proximal end, thereby causing the expandable body 21 to further expand in the radial direction, and the puncture hole Hh to be pushed open in the radial direction, as shown in FIG.

[0056] After the puncture hole Hh is dilated, hemodynamics is confirmed in step S4. As shown in FIG. 7, the surgeon delivers a hemodynamics confirmation device 220 to the right atrium HRa via the inferior vena cava IV. A known echo catheter, for example, can be used as the hemodynamics confirmation device 220. The surgeon can display the echo image acquired by the hemodynamics confirmation device 220 on a display device such as a monitor, and can confirm the amount of blood passing through the puncture hole Hh based on the displayed result.

[0057] Next, in step S5, the surgeon performs a maintenance procedure to maintain the size of the puncture hole Hh. In the maintenance procedure, high-frequency energy is applied to the edge of the puncture hole Hh through the electrode unit 22, thereby cauterizing (heating and cauterizing) the edge of the puncture hole Hh with the high-frequency energy.

[0058] During cauterization, high-frequency energy from the electrode portion 22 generates heat at the edge of the puncture hole Hh, but the expandable body 21 has a heat insulating layer 71, which prevents the heat generated by cauterization from propagating to the blood. This makes it possible to prevent thrombus formation due to cauterization.

[0059] When the living tissue near the edge of the puncture hole Hh is cauterized through the electrode portion 22, a denatured portion is formed near the edge where the living tissue is denatured. Because the living tissue in the denatured portion loses its elasticity, the puncture hole Hh can maintain the shape it had when it was expanded by the expander 21.

[0060] After the maintenance treatment, the hemodynamics is checked again in step S6, and if the amount of blood passing through the puncture hole Hh is the desired amount, the surgeon reduces the diameter of the expandable body 21, stores it in the storage sheath 25, and removes it from the puncture hole Hh. Then, the entire medical device 10 is removed from the living body, completing the treatment.

[0061] Next, modified examples of the expandable body will be described. As shown in Fig. 10, an expandable body 80 of a first modified example has a frame 81 that defines its shape. The frame 81 is formed by connecting a plurality of heat insulating members 82 with hinge portions 84. The heat insulating members 82 can be made of fine ceramics, zirconia, or the like, which have low thermal conductivity. However, the heat insulating members 82 may also be made of materials other than these.

[0062] The expandable body 80 has a recess 83 that deforms as it expands and contracts, and an electrode portion 85 is disposed in the recess 83. The recess 83 can accommodate the edge of the puncture hole Hh within the receiving space 83a. Because the heat insulating member 82 is formed of a material with low flexibility, the provision of a hinge portion 84 allows the expandable body 80 to expand and contract without being damaged. Because the entire expandable body 80 is formed of the heat insulating member 82, the first surface 86, the second surface 87, the third surface 88, and the fourth surface 89 all have heat insulating layers. By forming the entire expandable body 80 from the heat insulating member 82, when high-frequency energy is output from the electrode portion 85 with biological tissue accommodated in the receiving space 83a of the recess 83, it is possible to suppress the propagation of heat generated by cauterization to the blood.

[0063] As shown in FIG. 11 , the expandable body 90 of the second modified example has a frame 91 that defines its shape. The frame 91 has a heat insulating member 92 in a recess 93. The heat insulating member 92 can be made of fine ceramics, zirconia, or other materials with low thermal conductivity. However, the heat insulating member 92 may also be made of other materials. Because the recess 93 is formed of the heat insulating member 92, the first surface 96, the second surface 97, the third surface 98, and the fourth surface 99 all have heat insulating layers.

[0064] As shown in FIG. 12, the heat insulating member 92 has a bottom portion 92a, a base-side upright portion 92b, a tip-side upright portion 92c, and a back support portion 92d, and the base-side upright portion 92b has an electrode portion 95. The heat insulating member 92 also has a plurality of engaging portions 92e. The frame 91 has engaged portions 91a with which the engaging portions 92e of the heat insulating member 92 engage. By engaging the engaging portions 92e with the engaged portions 91a, the heat insulating member 92 can be integrated with the frame 91. This reduces the thermal conductivity of the recessed portion 93 of the expandable body 91, and when high-frequency energy is output from the electrode portion 95 with biological tissue received in the receiving space 93a of the recessed portion 93, it is possible to suppress the transmission of heat generated by cauterization to the blood.

[0065] The heat insulating layer 107 may be provided on two of the first surface 103, second surface 104, third surface 105, and fourth surface 106 that sandwich the receptive space 102a. As shown in FIG. 13(a), the expandable body 100 of the third modified example has the heat insulating layer 107 on the surface of the recess 102 opposite to the side facing the receptive space 102a. That is, the heat insulating layer 107 is provided on the second surface 104 and the fourth surface 106 so as to sandwich the receptive space 102a. The two surfaces having the heat insulating layer 107 may be in any other combination as long as they sandwich the receptive space 102a, and may be provided on the first surface 103 and the fourth surface 106, for example.

[0066] 13(b), the heat insulating layer 107 may be provided on the first surface 103 and the third surface 105 in addition to the second surface 104 and the fourth surface 106. In either case, the heat insulating layer 107 can reduce the propagation of heat in the recess 102, so that when high-frequency energy is output from the electrode portion 108 with biological tissue received in the receiving space 102a of the recess 102, the propagation of heat generated by cauterization to the blood can be suppressed.

[0067] 14, the heat insulating layer 107 is formed as a sheet having the shape of the recess 102. The heat insulating layer 107 is adhesively fixed to the portion of the frame 101 where the recess 102 is shown shaded in the figure. The method of fixing the heat insulating layer 107 is not limited to adhesive, and it may also be fixed to the frame 101 using a wire or the like.

[0068] 15, the expandable body 110 of the fourth modification has an electrode portion 118 on the proximal rising portion 112b of the recess 112, and the distal rising portion 112c serves as the opposing surface. The heat insulating layer 117 is provided on the contact surface with the electrode portion 118 of the first surface 113 and on the third surface 115.

[0069] As shown in Fig. 16(a), the heat insulating layer 117 on the first surface 113 can be provided between a flexible substrate 119 provided along the surface of a frame 111 that defines the shape of the expandable body 110 and the electrode unit 118. Also, as shown in Fig. 16(b), the heat insulating layer 118 having the electrode unit 118 fixed to its surface may be fixed to the frame 111. In this case, the heat insulating layer 118 is fixed to the frame 111 with adhesive, wire, or the like.

[0070] As shown in Fig. 17, the extendable body 120 of the fifth modified example has an electrode assembly 121 having an electrode portion 122 as a separate body from a frame 123. The frame 123 has a recess 124 that defines a receiving space 124a, and the recess 124 has a base-side upright portion 124b and a tip-side upright portion 124c. A base-side through-hole 124e and a tip-side through-hole 124f are formed in a bottom portion 124d of the recess 124. A backrest portion through-hole 124h is formed in a backrest portion 124g.

[0071] The electrode assembly 121 has an inner wiring portion 121a that is exposed to the receiving space 124a and on which the electrode portion 122 is disposed. The electrode assembly 121 has a folded wiring portion 121b that is located distally of the inner wiring portion 121a and passes through the base-side through-hole 124e and the tip-side through-hole 124f and is folded back at the back support portion through-hole 124h. The folded wiring portion 121b passes through the base-side through-hole 124e and is disposed between the inner wiring portion 121a and the base-side standing portion 124b.

[0072] The expandable body 120 has a tube 125 that covers and secures the base-end upright portion 124b and the folded wiring portion 121b. The tube 125 is made of a material such as nylon elastomer that shrinks when heated. The tube 125 has low thermal conductivity and functions as a heat insulating layer. The tube 125 is also provided on the back support portion 124g. As a result, the first surface 126, second surface 127, third surface 128, and fourth surface 129 of the recess 122 are covered with the tube 125, which serves as a heat insulating layer, and the heat generated during cauterization can be prevented from being transmitted to the blood.

[0073] Next, a fifth modified example of the expandable body will be described. As shown in FIGS. 18(a) and 18(b), the expandable body 130 of the fifth modified example has a heat insulating cover portion 135 provided on the back side of the back support portion 134, in an area of ​​the base-end upright portion 132c surrounded by outer edge portions 133 on both sides. The frame 131 of the expandable body 130 is made of a metal material. The heat insulating cover portion 135 is made of a material that has low thermal conductivity and flexibility. Examples of such a material include rubber or foam rubber, such as silicone rubber. However, the heat insulating cover portion 135 may be made of a material other than these.

[0074] As shown in Figure 19, an electrode portion 136 is arranged on the base end side standing portion 132b of the recess 132, and the surface opposite to the surface facing the receiving space 132a of the tip end side standing portion 132c, which serves as the opposing surface, is covered with an insulating cover portion 135.

[0075] When high-frequency energy is output from the electrode 136 to the biological tissue, the edge of the puncture hole Hh becomes hot, and the heat is propagated to the facing surface. A heat-insulating cover 135 is provided on the facing surface, covering the surface that comes into contact with blood. Therefore, the heat generated by cauterization is prevented from propagating to the blood by the heat-insulating cover 135. In this example, the electrode 136 may also be provided on the tip-side upright portion 132c. The same applies to the following modified examples in which a heat-insulating cover is provided.

[0076] Next, modified examples of the medical device will be described. As shown in Fig. 20, a medical device 15 of a first modified example has a second expansion body 145 on the inside in the expansion direction of a frame 141 of an expansion body 140. The second expansion body 145 has a second frame 146 that fits along the inside in the expansion direction of the frame 141, and a heat-insulating cover portion 147. The electrode portion 143 is arranged to face the receiving space 142a of the recess 142.

[0077] 21 , the second frame 146 of the second extension body 145 has a shape that conforms to the frame 141, and a heat insulating cover portion 147 is provided in the portion that covers the recess 142. The second frame 146 is radially expandable and contractible together with the frame 141. When the frame 141 expands radially, the second frame 146 also expands radially, and the heat insulating cover portion 147 can tightly fit and cover the surface of the recess 142 of the frame 141 opposite to the surface facing the receiving space 142a. In this way, the heat insulating cover portion 147 may be provided on the second extension body 145, which is separate from the frame 141, to cover the surface of the recess 142 opposite to the side facing the receiving space 142a.

[0078] 22, in the medical device 15 of the first modification, the electrode portion 143 may be provided on the bottom portion 142d of the recess 142. In this case, too, the heat insulating cover portion 147 of the second frame 146 can tightly cover the surface of the recess 142 of the frame 141 opposite to the surface facing the receiving space 142a.

[0079] As shown in FIG. 23, the medical device 16 of the second modification includes a second expansion body 155 having a mesh made of a woven multiplicity of wires on the inside of the expansion body 150 in the expansion direction. The electrode portion 153 is arranged to face the receiving space 152a of the recess 152. The second expansion body 155 is radially expandable and contractible together with the expansion body 150. As shown in FIG. 24, when the second expansion body 155 is radially expanded, it has an outer shape that conforms to the inside of the expansion body 150, and has heat-insulating cover portions 156 at four locations corresponding to the circumferential positions of the frame 151. As the second expansion body 155 expands together with the expansion body 150, the heat-insulating cover portions 156 can tightly fit and cover the surface of the recess 152 of the frame 151 opposite to the surface facing the receiving space 152a. In this way, a second expansion body 155 having a heat insulating cover portion 156 may be provided inside the expansion body 150 to cover the surface of the recess 152 opposite to the side facing the receiving space 152a.

[0080] As shown in FIG. 25, the medical device 17 of the third modification is provided with a balloon 166 as a second expandable body 165 that functions as a heat insulating cover on the inside in the expansion direction of the expandable body 160. The electrode portion 163 is arranged to face the receiving space 162a of the recess 162. The balloon 166 can be expanded radially by injecting an expansion fluid through an expansion lumen (not shown) provided in the shaft portion 20. As shown in FIG. 26(a), the balloon 166 has an outer shape that has a recess 166a that fits along the inside of the expandable body 160. The balloon 166 may have a shape that does not have a recess, as shown in FIG. 26(b), as long as it can flexibly deform according to the shape of the expandable body 160.

[0081] By expanding the balloon 166 while the expandable body 160 is expanded and bringing its surface into close contact with the inside of the expandable body 160, it is possible to prevent the recess 162 of the expandable body 160 from coming into contact with the blood. This prevents the heat generated when the electrode portion 163 cauterizes the biological tissue from being transmitted to the blood, thereby preventing the occurrence of thrombus.

[0082] As shown in FIG. 27, the balloon 167 only needs to cover the recessed portion 162 of the expandable body 160 from the inside, and does not need to be large enough to cover the entire expandable body 160.

[0083] The expandable body is not limited to one that grasps biological tissue. The expandable body 170 shown in Fig. 28 receives biological tissue in the receiving space 172a of the recess 172, but does not grasp it. The recess 172 has a base-side upright portion 173 and a tip-side upright portion 174. In this state, high-frequency energy is applied to the biological tissue from the electrode portion 175. A heat insulating layer 176 is provided on the base-side upright portion 173 of the recess 172, which can prevent heat generated by cauterization from being transmitted to the blood.

[0084] The expandable body is not limited to one formed from multiple wire members. The expandable body 180 shown in Fig. 29 is formed in a mesh shape with branching and merging wire members. The expandable body 180 has a recess 182 in which an electrode member 183 is disposed. A heat insulating layer 185 is provided in the recess 182. In this example, the shaft portion does not have a traction shaft, and the puncture hole Hh can be expanded only by the self-expansion force of the expandable body 180.

[0085] As described above, the medical device 10 according to this embodiment comprises an expansion body 21 that can expand and contract radially, a long shaft portion 20 having a tip portion 30 including a base end fixing portion 31 to which the base end of the expansion body 21 is fixed, and an electrode portion 22 provided along the expansion body 21, and the expansion body 21 has a recess 51 that recesses radially inward when the expansion body 21 is expanded and defines a receiving space 51b that can receive biological tissue, and the recess 51 has a bottom portion 51a located at the innermost radial position, a base end side upright portion 52 that extends radially outward from the base end of the bottom portion 51a, and a tip end side upright portion 53 that extends radially outward from the tip of the bottom portion 51a, and the base end side upright portion 52 is The extension body 21 has a first surface 60 facing the space 51b and a second surface 61 opposite the first surface 60, and the tip side upright portion 53 has a third surface 62 facing the receiving space 51b and a fourth surface 63 opposite the third surface 62, and one of the base side upright portion 52 and the tip side upright portion 53 is an electrode placement portion in which the electrode portion 22 is placed so as to face the receiving space 51b, and the other of the base side upright portion 52 and the tip side upright portion 53 is an opposing surface portion facing the electrode portion 22, and the extension body 21 has an insulating layer 71 on at least one of the first surface 60, the second surface 61, the third surface 62, and the fourth surface 63 so as to face the electrode portion 22 across the receiving space 51b. The medical device 10 configured in this manner has an insulating layer 71 provided on the surface facing the electrode portion 22 across the receiving space 51b, making it difficult for heat from biological tissue heated to a high temperature by the energy applied from the electrode portion 22 or from the heat-generating portion itself, such as the electrode portion 22, to be transmitted to the blood, thereby reducing the risk of thrombus formation.

[0086] The expandable body 21 may also have a frame 70 that defines the shape of the expandable body 21, and a heat insulating layer 71 that is provided on the surface of the frame 70. This allows the heat insulating layer 71 to be provided while ensuring the flexibility of the expandable body 21.

[0087] The heat insulating layer 71 may also be provided over substantially the entire surfaces of the frame 70 on the inner side in the expansion direction and on the outer side in the expansion direction, thereby improving the heat insulating properties of the expandable body 21 and reliably reducing the propagation of heat associated with cauterization.

[0088] Furthermore, the heat insulating layer 107 may be provided on two or more of the first surface 103, the second surface 104, the third surface 105, and the fourth surface 106, so as to sandwich the receiving space 102a. This makes it possible to reduce the propagation of heat caused by cauterization on both sides of the recess 102.

[0089] The heat insulating layer 71 may be provided on the inner surface or outer surface of the bottom 51a in the expansion direction, thereby reducing heat propagation at the bottom 51a of the recess 51.

[0090] The expandable body 120 may also have a tube 125 that covers the frame 123 and functions as a heat insulating layer. This allows the heat insulating layer to be easily formed simply by attaching the tube 125 to the frame 123.

[0091] The expandable body 90 may also have a frame 91 that defines the shape of the expandable body 90, and the frame 91 may have a heat insulating member 92 that has a heat insulating layer at least in the region of the recess 93. This allows the heat insulating layer to be easily formed by fixing the heat insulating member 92 to the frame 91.

[0092] Furthermore, the medical device 10 according to this embodiment comprises an expansion body 130 that can expand and contract radially, a long shaft portion 20 having a tip portion 30 including a base end fixing portion 31 to which the base end of the expansion body 130 is fixed, an electrode portion 136 provided along the expansion body 130, and a heat insulating cover portion 135 that covers at least a portion of the expansion body 130, and the expansion body 130 has a recess 132 that recesses radially inward when the expansion body 130 is expanded and defines a receiving space 132a that can receive biological tissue, The recess 132 has a bottom portion located at the innermost side in the radial direction, a base-side upright portion 132b extending radially outward from the base end of the bottom portion, and a tip-side upright portion 132c extending radially outward from the tip of the bottom portion, the electrode portion 136 is disposed in the recess 132 so as to face the receiving space 132a, and the heat-insulating cover portion 135 is configured to cover at least a portion of the surface of the recess 132 opposite to the surface facing the receiving space 132a in the vicinity of the electrode portion 136. In the medical device 10 configured in this manner, the heat-insulating cover portion 135 covers at least a portion of the surface of the recess 132 opposite to the surface facing the receiving space 132a in the vicinity of the electrode portion 136, making it possible to make it difficult for heat from biological tissue heated by energy applied from the electrode portion 136 to be transmitted to the blood, thereby reducing the risk of thrombus formation.

[0093] Alternatively, one of the base-end side standing portion 132b and the tip-end side standing portion 132c may be an electrode placement portion in which the electrode portion 136 is placed so as to face the receiving space 132a, and the other of the base-end side standing portion 132b and the tip-end side standing portion 132c may be an opposing surface portion facing the electrode portion 136, and the heat-insulating cover portion 135 may be provided on the surface of the opposing surface portion opposite the surface facing the receiving space 132a. This prevents blood from coming into contact with the opposing surface portion, thereby reliably reducing the propagation of heat generated during cauterization.

[0094] The expansion body 140 has a frame 141 that defines the shape of the expansion body 140, and the medical device 15 further includes a second expansion body 145 that has a heat insulating cover portion 147 on the inside in the expansion direction of the frame 141 and is radially expandable and contractible, and the heat insulating cover portion 147 may cover at least the surface of the recess 142 of the frame 141 opposite to the surface facing the receiving space 142a. This allows the second expansion body 145 to expand as the expansion body 140 expands, and the surface of the recess 142 opposite to the side facing the receiving space 142a can be covered by the heat insulating cover portion 147.

[0095] The second expansion body 145 may also have a second frame 146 that defines the shape of the second expansion body 145, and a heat insulating cover portion 147 that is disposed on at least a part of the second frame 146. This allows the heat insulating cover portion 147 to be provided while ensuring the flexibility of the second expansion body 145.

[0096] The second expandable body 155 may also have a mesh made of a large number of woven wires and a heat insulating cover portion 156 arranged on at least a part of the mesh. The mesh can flexibly deform to fit the shape of the expandable body 150, so that the heat insulating cover portion 156 can be brought into closer contact with the expandable body 150, thereby improving heat insulation.

[0097] The second expandable body 165 may also have a radially expandable balloon 166 that functions as a heat insulating cover. This allows the inside of the expandable body 160 to be covered with the balloon 166, more reliably preventing the surface of the recess 162 of the frame 161 opposite to the surface facing the receiving space 162a from coming into contact with blood, and more reliably reducing heat propagation.

[0098] Furthermore, in the shunt formation method of this embodiment, when voltage is applied to the electrode portion 22, the recess 51 of the expansion body 21 is insulated by the insulating layer 71 or the insulating cover portion 135, making it difficult for the heat associated with cauterization to propagate to the blood, thereby reducing the risk of thrombus formation.

[0099] The present invention is not limited to the above-described embodiment, and various modifications may be made by those skilled in the art within the technical spirit of the present invention. In the examples of Figures 28 and 29, the expandable bodies 170 and 180 may have insulating cover portions instead of the insulating layers 176 and 185.

[0100] This application is based on Japanese Patent Application No. 2020-164555, filed on September 30, 2020, the disclosures of which are incorporated herein by reference in their entirety. [Explanation of symbols]

[0101] 10 Medical Devices 11 Guidewire 15 Medical Devices 20 Shaft section 21 Extension 22 Electrode section 23 Control section 25 Storage sheath 26 Traction shaft 30 Tip 31 Base end fixing part 32 Shaft extension 33 Tip fixing part 35 Tip member 40 cabinets 41 Operation dial 42 Conversion Mechanism 50 Wire section 51 recess 51a bottom 51b Receptive Space 52 Proximal upright part 53 Tip side upright part 55 outer edge 56 Backrest 57 Through hole 58 Space section 60 Page 1 61 2nd page 62 3rd page 63 Page 4 70 frames 71 Insulation layer 72 Biocompatible Coatings

Claims

1. an expansion body that is radially expandable and contractible; a long shaft portion having a distal end portion including a base end fixing portion to which the base end of the expansion body is fixed; an electrode portion provided along the expandable body and applying energy to the biological tissue to maintain the size of the hole formed in the biological tissue; Equipped with the expandable body has a recess that is recessed radially inward when the expandable body is expanded and defines a receiving space capable of receiving biological tissue, the recess has a bottom portion located at the innermost side in the radial direction, a base end side upright portion extending radially outward from a base end of the bottom portion, and a tip end side upright portion extending radially outward from a tip end of the bottom portion, The base end side upright portion has a first surface facing the receiving space and a second surface opposite to the first surface, the tip side standing portion has a third surface facing the receiving space and a fourth surface opposite to the third surface, one of the base-end side standing portion and the tip-end side standing portion is an electrode arrangement portion in which the electrode portion is arranged so as to face the receiving space and not face the second surface and the fourth surface, and the other of the base-end side standing portion and the tip-end side standing portion is an opposing surface portion that faces the electrode portion, the extension body has a heat insulating layer on at least one of the first surface, the second surface, the third surface, and the fourth surface, the heat insulating layer facing the electrode portion across the receiving space; the expansion body includes a frame formed of a metal that defines the shape of the expansion body and includes the electrode placement portion, and the heat insulating layer that is provided on a surface of the frame, A medical device in which the heat insulating layer is provided on at least the first surface and the third surface so as to separate the electrode portion from the electrode placement portion of the frame and sandwich the receiving space.

2. A medical device as described in claim 1, further comprising an electrode assembly having the electrode portion and provided separately from the frame.

3. The medical device according to claim 1 , wherein the heat insulating layer is provided over substantially the entire surfaces of the frame on the inner side in the expansion direction and on the outer side in the expansion direction.

4. The medical device of claim 1 , wherein the heat insulating layer is also provided on the second surface and the fourth surface.

5. The medical device according to claim 1 , wherein the heat insulating layer is further provided on an inner surface or an outer surface of the bottom portion in the expansion direction.

6. The medical device of claim 1 , wherein the expander comprises a tube covering the frame that functions as the thermal insulation layer.

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