JPWO2019181612A1 - Medical device - Google Patents

Abstract

Provided is a medical device capable of limiting the range in which an electric current is applied in ablation to a target site. A medical device (10) that is inserted into a living body cavity to ablate living tissue, and has a long shaft portion (21) and an electrode portion (40) arranged at the tip of the shaft portion (21). The electrode portion (40) has a pressure-sensitive conductive member (42) that produces conductivity by being pressurized or compressed, and a group that is deformable in the radial direction and has conductivity and a voltage is applied. A medical device (10) having a member (41) and having at least a part of the surface of the base member (41) on the living tissue side covered with a pressure-sensitive conductive member (42).

Description

The present invention relates to a medical device that is inserted into a living body and treats a living tissue by ablation.

As a medical device, a device that performs treatment by an irreversible electric drilling method (IRE) is known. The irreversible electrosurgical method is attracting attention because it is non-thermal and can suppress damage to surrounding blood vessels and nerves. For example, a medical device that treats a cancer that is difficult to remove by surgery by using an irreversible electric perforation method is known.

For atrial fibrillation caused by abnormal excitement in the myocardial sleeve of the wall of the pulmonary vein, pulmonary vein isolation may be performed to cauterize the junction between the pulmonary vein and the left atrium and destroy the myocardial cells. .. In pulmonary vein isolation, high frequency waves are generated from the tip of the ablation catheter to cauterize and necrotize the myocardium in dots. The ablation catheter is moved to cauterize the pulmonary vein inflow in a circumferential manner to isolate the pulmonary vein.

When treating the lumen of a living body in this way, it is conceivable to apply the above-mentioned irreversible electric drilling method. Medical devices that apply the irreversible electrosurgical method to the lumen of a living body include, for example, those shown in the following patent documents. The medical device of Patent Document 1 has a plurality of electrodes that can be expanded in the radial direction, and electricity can flow between the electrodes while the electrodes are in close contact with the living tissue. Further, Patent Document 2 discloses a medical device having an electrode to which an irreversible electric perforation method can be applied to an arterial lesion. Further, Patent Document 3 discloses a medical device that can be inserted into the ventricle and can reduce myocardial tissue by an irreversible electric perforation method.

U.S. Patent Publication No. 2014/0039491 U.S. Patent Publication No. 2009/0248012 International Publication No. 2014/195933

When applying the irreversible electrosurgical method to the living body cavity or cauterizing, the electrode does not always come into contact with only the necessary part, so that an electric current may be applied to the tissue outside the target. Also, if part of the electrode comes into contact with blood, electrical energy may dissipate into the blood.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a medical device capable of limiting the range in which an electric current is applied in ablation to a target site.

The medical device according to the present invention that achieves the above object is a medical device that is inserted into a living body cavity to ablate living tissue, and includes a long shaft portion and an electrode portion arranged at the tip of the shaft portion. The electrode portion has a pressure-sensitive conductive member that produces conductivity by being pressurized or compressed, and a base member that is deformable in the radial direction and has conductivity and a voltage is applied. The pressure-sensitive conductive member covers at least a part of the surface of the base member on the living tissue side.

In the medical device configured as described above, only the portion of the electrode portion that receives the pressure from the living tissue is conducted, and the range in which the current is applied can be limited to the target portion.

It is a front view which shows the outline of the medical device in 1st Embodiment. It is sectional drawing around the tip part of a balloon catheter. It is sectional drawing which cut | cut the tip part of the medical device in the plane perpendicular to the axial direction. FIG. 4A is a cross-sectional view of the electrode portion before compression (FIG. 4A), and FIG. 4B is a cross-sectional view of the electrode portion after compression. It is a partially enlarged plan view of the electrode part. It is a front view of the tip part of the medical device in the state where the electrode part is expanded at the target part in a living body. It is a front view of the tip part of the medical device in 2nd Embodiment. It is a partially enlarged plan view of the electrode part. It is a front view of the tip part of the medical device in the state where the electrode part is expanded. It is a front view of the tip part of the medical device in 3rd Embodiment. It is a front view of the tip part of the medical device in 4th Embodiment. Front view of the tip of the medical device in a state where the electrode portion of the medical device having a balloon having a shape whose length in the direction perpendicular to the axial direction is larger than the length in the axial direction is expanded at a target site in the living body. Is.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The dimensional ratios in the drawings may be exaggerated and differ from the actual ratios for convenience of explanation. Further, in the present specification, the side of the medical device 10 to be inserted into the living body cavity is referred to as "tip" or "tip side", and the hand side to be operated is referred to as "base end" or "base end side". Ablation is an act of destroying a living tissue by an irreversible electrosurgical method or an act of destroying a living tissue by cauterization by heat or the like.

The medical device 10 of the first embodiment is percutaneously inserted into a living body cavity, contacts a living body tissue at a target site, applies an electric current, and carries out an irreversible electroporation method. The target of the medical device 10 of the present embodiment is a treatment in which an entrance portion of a pulmonary vein is electrically perforated over the entire circumference in pulmonary vein isolation. However, as will be described later, the medical device according to the present invention can also be applied to other treatments.

As shown in FIG. 1, the medical device 10 has an electrode portion 40 at the tip end portion of the long tubular outermost sheath body 30. In addition, the medical device 10 has a balloon catheter 20. The outermost sheath body 30 has a connecting wire 33 for applying a voltage to the electrode portion 40 along the length direction. The connection line 33 is connected to a power supply unit 12 provided outside the outermost sheath body 30. The power supply unit 12 can apply a voltage to the electrode unit 40. Further, a tip member 31 for fixing the electrode portion 40 is provided at the tip portion of the outermost sheath body 30.

The balloon catheter 20 has a balloon 22 at the tip of a long shaft portion 21, and a hub 23 at the base end of the shaft portion 21. In the balloon catheter 20, the shaft portion 21 is housed in the hollow inside of the outermost sheath body 30.

As shown in FIG. 2, the shaft portion 21 has a hollow outer tube 25 and an inner tube 26 which is a hollow internal support. The inner pipe 26 is housed inside the hollow of the outer pipe 25, and the shaft portion 21 has a double pipe structure. A guide wire lumen 27 through which the guide wire 11 is inserted is formed inside the hollow of the inner pipe 26. Further, an expansion lumen 28 for circulating the expansion fluid of the balloon 22 is formed inside the hollow inside of the outer tube 25 and outside the inner tube 26.

The inner pipe 26 projects further to the tip side than the tip of the outer pipe 25. The base end side end of the balloon 22 is fixed to the outer tube 25, and the tip end side end is fixed to the inner tube 26. As a result, the inside of the balloon 22 communicates with the expansion lumen 28. The balloon 22 can be expanded by injecting an expansion fluid into the balloon 22 via the expansion lumen 28. The expansion fluid may be a gas or a liquid, and for example, a gas such as helium gas, CO ₂ gas, O ₂ gas, or laughing gas, or a liquid such as physiological saline, a contrast medium, or a mixture thereof can be used.

The outermost sheath body 30, the outer tube 25, and the inner tube 26 are preferably formed of a material having a certain degree of flexibility. Examples of such a material include polyolefins such as polyethylene, polypropylene, polybutene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ionomer, or a mixture of two or more thereof, and a soft polyvinyl chloride resin. Examples thereof include fluororesins such as polyamide, polyamide elastomer, polyester, polyester elastomer, polyurethane and polytetrafluoroethylene, silicone rubber and latex rubber.

The balloon 22 is formed of a thin-film balloon film, and like the outer tube 25 and the inner tube 26, is formed of a flexible material. Further, the strength required to surely spread the electrode portion 40 is also required. As the material of the balloon 22, the ones mentioned above for the outer tube 25 and the inner tube 26 can be used, or other materials may be used. In particular, when cauterizing the surface of the heart chamber at the base of a blood vessel (pulmonary vein), if the inside of the blood vessel is cauterized, the blood vessel may contract due to spasm or the like. Therefore, the balloon diameter is set to about 20 mm to 30 mm in order to cauterize the surface of the heart chamber at the root of the blood vessel without cauterizing the inside of the blood vessel.

Next, the electrode portion 40 will be described. As shown in FIG. 1, the electrode portion 40 has a base member 41 which is a wire rod having conductivity and flexibility. A plurality of electrode portions 40 are provided in the circumferential direction. The tip of the base member 41 is fixed to the tip fixing member 45 fixed to the inner pipe 26. Further, the base end portion of the base member 41 is fixed to the tip member 31 of the outermost sheath body 30. Further, the base end portion of the base member 41 extends to the connecting portion 32 provided in the outermost sheath body 30 and is electrically connected to the connecting wire 33. Each base member 41 is connected to the power supply unit 12 via a separate connection line 33. As a result, a voltage can be applied from the power supply unit 12 between the base members 41 adjacent to each other in the circumferential direction.

The base member 41 is preferably thin and flexible, and can be formed of a conductive material such as a metal material. For example, Ni—Ti, FPC, or the like can be used as the base member 41. The base member 41 has a width of 0.1 to 2 mm, a length of 5 to 50 mm, and a thickness of 0.01 to 0.5 mm. However, the base member 41 may have other dimensions if necessary. By making the base member 41 softer than the hardness of the balloon 22 at the time of maximum expansion, the followability of the base member 41 to the balloon 22 can be enhanced.

The base member 41 is provided with a pressure-sensitive conductive member 42 on the outer peripheral surface in contact with the living tissue. The base member 41 has an insulating layer 44 on a surface other than the region where the pressure-sensitive conductive member 42 is provided. The pressure-sensitive conductive member 42 is an elastic body that does not have conductivity in a state where it is not pressurized or compressed, but becomes conductive in the thickness direction when it is pressurized or compressed. In the present embodiment, the pressure-sensitive conductive member 42 may have low elasticity. When the base member 41 expands in the radial direction, the outer peripheral surface on which the pressure-sensitive conductive member 42 is provided comes into contact with the living tissue. Therefore, the pressure-sensitive conductive member 42 is pressed against the living tissue by expanding the base member 41 in the radial direction in the living body.

The pressure-sensitive conductive member 42 has a width of 0.1 to 2 mm, a length of 5 to 30 mm, and a thickness of 0.01 to 0.5 mm. However, the pressure-sensitive conductive member 42 may have other dimensions if necessary.

In FIG. 1 and the like, only two electrode portions 40 are shown for simplification, but as shown in FIG. 3, a large number of electrode portions 40 are provided depending on the circumferential direction. In the present embodiment, six electrode portions 40 are evenly provided in the circumferential direction. The distance between the electrode portions 40 is preferably in the range of 0.1 to 1 mm, but may be other than this range. However, the number of electrode portions 40 may be larger or smaller than this. Further, the electrode portions 40 may be arranged unevenly in the circumferential direction. Although the voltage is applied between the adjacent electrode portions 40, an electrode may be arranged outside the body and a voltage may be applied between the electrode portion outside the body and the electrode portion 40.

Further, on the surface of the base member 41, the insulating layer 44 is provided in a region other than the region where the pressure-sensitive conductive member 42 is provided. As a result, the portion of the electrode portion 40 other than the pressure-sensitive conductive member 42 can be prevented from conducting.

As shown in FIG. 4A, the pressure-sensitive conductive member 42 is formed by uniformly containing the conductive particles 42b in the insulating material matrix 42a. The insulating material matrix 42a is a material having high insulating properties and elasticity, and rubber can be used, for example. Further, the conductive particles 42b are particles having conductivity, and for example, metal powder, metal vapor deposition powder, carbon or the like can be used. However, materials other than these may be used for the insulating material matrix 42a and the conductive particles 42b. FIG. 4A shows a state in which the pressure-sensitive conductive member 42 is in contact with the living body wall 62, but no pressure is applied. In this state, the pressure-sensitive conductive member 42 does not have conductivity because the conductive particles 42b are separated from each other. Therefore, even if a voltage is applied to the base member 41, no current flows through the living body wall 62.

FIG. 4B shows a state in which the pressure-sensitive conductive member 42 is pressed against the living body wall 62. In this state, the pressure-sensitive conductive member 42 is compressed in the thickness direction. Along with this, the conductive particles 42b in the pressure-sensitive conductive member 42 come into contact with each other to form a conductive path, and become conductive in the thickness direction of the pressure-sensitive conductive member 42. As a result, the base member 41 and the living body wall 62 are electrically connected to each other, so that a voltage can be applied to the base member 41 to allow an electric current to flow through the living body wall 62. At this time, the resistivity of the pressure-sensitive conductive member 42 in the thickness direction is preferably 2.5 Ω · m or less.

As shown in FIG. 5, the pressure-sensitive conductive member 42 is bonded to the base member 41 by an adhesive layer 43. The adhesive layer 43 is provided in a part of the surface of the pressure-sensitive conductive member 42. In FIG. 5, the adhesive layer 43 is provided on both sides of the pressure-sensitive conductive member 42 along the length direction. However, the region where the adhesive layer 43 is provided is not limited to this, and the adhesive layer 43 may be provided so as to cover the four circumferences of the edge portion of the pressure-sensitive conductive member 42. By providing the adhesive layer 43 in a part of the surface of the pressure-sensitive conductive member 42, the base member 41 and the pressure-sensitive conductive member 42 can be reliably conducted in other regions. Further, the base member 41 and the pressure-sensitive conductive member 42 may be joined by a conductive adhesive layer formed of a conductive adhesive. In this case, a conductive adhesive layer may be provided over the entire surface of the pressure-sensitive conductive member 42.

In the present embodiment, the pressure-sensitive conductive member 42 is provided only on a part of the outer peripheral side surface of the base member 41, and the insulating layer 44 is provided on the other surface of the base member 41. .. The region where the pressure-sensitive conductive member 42 is provided is a region that comes into pressure contact with the biological tissue when the base member 41 expands. It is desirable that the pressure-sensitive conductive member 42 is arranged at least in a region on the tip end side of the portion of the base member 41 that has the maximum diameter when expanded. When the base member 41 expands in the radial direction while being inserted into a tapered space from an opening like a pulmonary vein, the tip end side portion of the base member 41 strongly receives a reaction force against a pressing force. Therefore, by providing the pressure-sensitive conductive member 42 in this region, the base member 41 and the biological tissue can be reliably conducted with each other.

The pressure-sensitive conductive member 42 may be provided over substantially the entire length of the base member 41. Thereby, it is possible to correspond to various shapes of the living body lumen. Further, the pressure-sensitive conductive member 42 may be provided on the entire surface of the base member 41. In this case, the insulating layer 44 becomes unnecessary.

As shown in FIG. 6, the base member 41 is expanded in the radial direction by expanding the balloon 22 of the balloon catheter 20 in a state where the electrode portion 40 is inserted into the opening 61 of the biological lumen 60. A part is pressed against the living body wall 62. The base member 41 has an insulating layer 44 on a surface other than the region where the pressure-sensitive conductive member 42 is provided, and the pressure-sensitive conductive member 42 has conductivity only in the pressurized region. Therefore, the current from the base member 41 flows to the living tissue only in the region where the pressure-sensitive conductive member 42 is pressed against the living body wall 62, and no current flows in the other regions. Thereby, the range in which the electric current is applied to the living tissue can be limited, and the electric current can be prevented from being applied to the tissue other than the target. Further, it is possible to prevent the electric current from leaking to the blood from the region other than the region pressed against the biological tissue of the base member 41. The base end portion of the base member 41 may be made of a flexible member having conductivity. As the flexible member, for example, a spring member can be used. Since a part of the base member 41 is made of a flexible member having conductivity, when the balloon 22 is expanded, the electrode portion 40 can be expanded and deformed in the radial direction while the flexible member is extended, so that the electrode The portion 40 can be deformed while following the expansion of the balloon 22.

Next, a treatment method using the medical device 10 will be described. First, an introducer (not shown) is percutaneously punctured into a blood vessel by the Seldinger method or the like. Next, after inserting the guide wire 11, a guiding catheter (not shown) is inserted into the introducer, the guide wire 11 is projected toward the tip side, and then the tip of the guiding catheter is opened at the tip of the introducer. Insert into the blood vessel. After that, the guiding catheter is gradually pushed to the target site while leading the guide wire 11. The operator creates a through hole in the atrial septum by penetrating a predetermined puncture device from the right atrium side to the left atrium side. As the puncture device, for example, a device such as a wire with a sharp tip can be used. Delivery of the puncture device can be via a guiding catheter. The puncture device can also, for example, remove the guide wire from the guiding catheter and then deliver it to the atrial septum in place of the guide wire. The specific structure of the puncture device used to penetrate the atrial septum, the specific procedure for forming the through hole, and the like are not particularly limited. After forming the through hole, the through hole is expanded using a dilator, a guiding catheter is passed through the through hole, and a guide wire is used to push the through hole to a target site (for example, near a pulmonary vein). The guiding catheter may have a mechanism for moving the tip of the guiding catheter.

Next, the end of the guide wire 11 is inserted into the opening at the tip of the guide wire lumen 27 of the balloon catheter 20 in the contracted state of the balloon 22, and the guide wire 11 is pulled out from the hub 23. Next, the balloon catheter 20 is inserted from the tip of the guiding catheter inserted into the blood vessel together with the electrode portion 40 and the outermost sheath body 30, and the balloon catheter 20 and the electrode portion 40 are inserted along the guide wire 11. And push forward the outermost sheath body 30.

After the electrode portion 40 is inserted to the entrance of the pulmonary vein, which is the target position, the expansion fluid is supplied into the balloon 22 via the expansion lumen 28 to expand the balloon 22. As a result, as shown in FIG. 6, the base member 41 has a shape that is expanded in the radial direction by the balloon 22. As described above, the base member 41 that expands in the radial direction and is pressed against the living body wall 62 conducts with the living body tissue only in the region where pressure is applied via the pressure-sensitive conductive member 42. In this state, a voltage is applied between the base members 41 from the power supply unit 12.

First, a pulsed voltage is applied from the power supply unit 12 to the pair of base members 41 and 41 adjacent to each other in the circumferential direction. As a result, a current flows between the pair of base members 41 and 41 adjacent to each other in the circumferential direction. Next, a pulsed voltage is applied to the other pair of base members 41, 41 adjacent in the circumferential direction. The voltage is sequentially applied to all the paired base members 41 and 41 adjacent in the circumferential direction. An example of the applied voltage is given below. The electric field strength applied by the power supply unit 12 is 1500 V / cm, and the pulse width of the voltage is 100 μsec. The voltage application to all the pairs of the electrode portions 40 adjacent to each other in the circumferential direction is repeated 60 to 180 times in a cycle of once every 2 seconds according to the myocardial refractory period. This causes the cells at the entrance of the pulmonary vein to become necrotic all around.

When the voltage application is complete, the balloon 22 is deflated. As a result, the base member 41 also contracts in the radial direction. Then, all the instruments inserted into the blood vessels are removed to complete the procedure.

Next, a second embodiment of the present invention will be described. As shown in FIG. 7, in the electrode portion 70 of the present embodiment, the base member 71 is fixed to the surface of the balloon 22. The base end portion of the base member 71 is connected to the connecting line 33 by the connecting portion 32 in the outermost sheath body 30. The tip of the base member 71 is located on the surface of the balloon 22. The balloon 22 and the base member 71 are joined by an adhesive or the like.

Since the base member 71 is fixed to the surface of the balloon 22, it extends with the expansion of the balloon 22. Therefore, the base member 71 is made of a material having conductivity and elasticity. As such a material, for example, conductive rubber can be used. The dimensions of the base member 71 are the same as in the case of the first embodiment. Further, it is desirable that the electric resistance of the base member 71 is 100 Ω or less in the length direction.

As shown in FIG. 8, a pressure-sensitive conductive member 72 is provided on the outer peripheral surface of the base member 71. The pressure-sensitive conductive member 72 is joined to the base member 71 by adhesive layers 73 on both sides. The region of the pressure-sensitive conductive member 72 other than the adhesive layer 73 is in direct contact with the base member 71.

As the pressure-sensitive conductive member 72, a material containing conductive particles in the insulating material matrix is used as in the first embodiment. The dimensions and resistivity of the pressure-sensitive conductive member 72 are the same as those in the first embodiment. Further, in the present embodiment, since the pressure-sensitive conductive member 72 expands with the expansion of the balloon 22, a material having elasticity is used.

As shown in FIG. 9, by expanding the balloon 22, the base member 71 fixed to the balloon 22 is expanded and deformed in the radial direction. At this time, the pressure-sensitive conductive member 72 is pressed against the living tissue, so that the base member 71 and the living tissue are electrically connected, and an electric current can be applied to the living tissue. In this way, the base member 71 may be fixed to the balloon 22.

Next, a third embodiment of the present invention will be described. As shown in FIG. 10A, the electrode portion 40 of the present embodiment has the same configuration as the electrode portion 40 of the first embodiment. On the other hand, in the present embodiment, the balloon catheter 20 is not provided, and the long tubular shaft portion 80 is provided. The tip fixing member 45 is fixed to the shaft portion 80. The shaft portion 80 can slide and move toward the proximal end side with respect to the outermost sheath body 30.

As shown in FIG. 10B, when the shaft portion 80 is slid to the proximal end side with respect to the outermost sheath body 30, the tip fixing member 45 fixed to the shaft portion 80 is moved to the outermost sheath body 30 side. Get closer to. The base end portion of the base member 41 is fixed to the outermost sheath body 30, and the tip end portion of the base member 41 fixed to the tip fixing member 45 moves to the outermost sheath body 30 side, so that the base member 41 Expands radially. As a result, the pressure-sensitive conductive member 42 is pressed against the living tissue, the base member 41 and the living tissue are made conductive, and an electric current can be applied to the living tissue. In this way, the base member 41 can be expanded without providing the balloon catheter 20. Further, the base member 41 may be self-expandable by shaping Ni—Ti or the like.

Next, a fourth embodiment of the present invention will be described. As shown in FIG. 11A, in the present embodiment, the balloon 92 is provided at the tip of the shaft portion 90, and the pressure-sensitive conductive member 93 is provided on the surface of the balloon 92. An insulating layer 94 is provided on the surface of the balloon 92 other than the region where the pressure-sensitive conductive member 93 is provided. The balloon 92 of the present embodiment is made of a conductive resin material and corresponds to a base member. The balloon 92 is electrically connected to the connecting wire 33 of the outermost sheath body 30. The pressure-sensitive conductive member 93 has elasticity so that it can be expanded together with the balloon 92. The pressure-sensitive conductive member 93 may be provided on the entire surface of the balloon 92. In this case, the insulating layer 94 is unnecessary.

As shown in FIG. 11B, by expanding the balloon 92, the pressure-sensitive conductive member 93 is also expanded in the radial direction. In the present embodiment, an electrode for applying a voltage to the balloon 92, which is a base member, is arranged outside the body. By applying a voltage between the extracorporeal electrode and the balloon 92 that conducts in the region where pressure is applied to the pressure-sensitive conductive member 93, a current can be applied to the living tissue. In this way, it is possible to pass an electric current using the balloon 92 as a base member.

As described above, the medical device 10 according to the present embodiment is a medical device 10 that is inserted into a living body cavity and ablates a living tissue, and is arranged at a long shaft portion 21 and a tip portion of the shaft portion 21. The electrode portion 40 has a base member 41 that is deformable in the radial direction and has conductivity and a voltage is applied, and at least the surface of the base member 41 that comes into contact with the biological tissue. It has a pressure-sensitive conductive member 42 that partially covers the pressure-sensitive conductive member 42, and the pressure-sensitive conductive member 42 is pressurized or compressed to generate conductivity. According to the medical device 10, only the portion of the electrode portion 40 that receives the pressure from the living tissue is conducted, and the range in which the current is applied can be limited to the target portion.

Further, if the pressure-sensitive conductive member 42 is an elastic body of an insulating material containing conductive particles, the conductive particles form a conductive path by pressurization, so that only the pressurized region is conductive. Can have.

Further, the pressure-sensitive conductive member 42 and the base member 41 can be joined via the adhesive layer 43 in a part of the regions so that at least a part of the regions are in direct contact with each other. Thereby, the continuity between the base member 41 and the pressure-sensitive conductive member 42 can be ensured.

Further, if the pressure-sensitive conductive member 42 and the base member 41 are joined via a conductive adhesive layer, the conduction between the base member 41 and the pressure-sensitive conductive member 42 can be ensured.

Further, in the base member 41, if the region other than the region where the pressure-sensitive conductive member 42 is provided is covered with the insulating layer 43, the region other than the pressure-sensitive conductive member 42 can be prevented from conducting. Can be done.

Further, the electrode portion 40 can be deformed in the radial direction of the living body cavity, and the pressure-sensitive conductive member 42 can be arranged in a region on the tip side of the portion having the maximum diameter of the base member 41. .. As a result, when the base member 41 is expanded and deformed while being inserted into the tapered lumen, the pressure-sensitive conductive member 42 is arranged at a portion that receives a large force, and reliable conduction is possible. ..

Further, if the pressure-sensitive conductive member 42 is provided over a substantially overall length in the length direction of the base member 41, it can correspond to a cavity having various shapes.

Further, the base member 41 is a wire rod, and if the pressure-sensitive conductive member 42 is provided on at least a part of the outer peripheral side of the base member 41, the base member 41 can be easily expanded and deformed and comes into contact with the living body cavity. Can be made to.

Further, if the balloon catheter 20 is provided with the balloon 22 at the tip of the shaft portion 21, the base member 41 is arranged around the balloon 42, and the base member 41 is deformed by the expansion of the balloon 42. The base member 41 can be reliably expanded and deformed by the expanding force of the balloon 22.

Further, it has a balloon catheter 20 provided with a balloon 22 at the tip of the shaft portion 21, and the base member 71 has elasticity and is joined to the surface of the balloon 22, and is at least on the outer peripheral side of the base member 71. A pressure-sensitive conductive member 72 may be provided in a part thereof. As a result, the base member 71 can be reliably expanded and deformed by the expanding force of the balloon 22.

Further, a balloon catheter having a balloon 92 provided at the tip of the shaft portion 90 is provided, the balloon 92 is a conductive base member, and a pressure-sensitive conductive member 93 is provided on at least a part of the outer surface of the balloon 92. Can be done. As a result, the balloon 92 and the living tissue can be made conductive via the pressure-sensitive conductive member 93.

Further, the base member 41 is fixed to the outermost sheath body 30 whose tip end is provided on the shaft portion 80 and whose base end portion is provided on the outer peripheral side of the shaft portion 80, and the shaft portion 80 is fixed to the outermost sheath body 30. By moving the base member 41 to the base end side, the base member 41 can be deformed. As a result, the base member 41 can be expanded and deformed by operating the shaft portion 80 without providing a balloon.

The present invention is not limited to the above-described embodiment, and various modifications can be made by those skilled in the art within the technical idea of the present invention. For example, in the above-described embodiment, the pressure-sensitive conductive member 42 is bonded to the base member 41 by an adhesive, but it may be mechanically bonded by a chuck member. The chuck member may be made of metal, for example, and may have a U-shape. Since the chuck member is made of metal, it can also be used as a marker. Further, the balloons shown in the first, second and fourth embodiments may be made of a non-stretchable material. In this case, the base material of the electrode portion does not have to have elasticity. When the balloon and the base material do not have elasticity, the balloon and the base material mounted on the balloon are brought into a state of being folded into a small diameter before being inserted into the living body. At the time of use, a method can be adopted in which the balloon and the base material are inserted into the target site in the living body and then expanded with a contrast medium or the like.

Further, in the above-described embodiment, the base member 41 has a square cross-sectional shape, but may have a round cross-sectional shape or another cross-sectional shape. Regardless of the cross-sectional shape, the pressure-sensitive conductive member 42 is provided on the surface on the side that comes into contact with the living tissue during expansion.

Further, although the medical device 10 of the above-described embodiment has been shown to be used for treating pulmonary veins, it may be used for treating other sites such as renal arteries, ascending vena cava, and ventricles.

Moreover, the shape of the balloon in the medical device is not limited to the above-described embodiment. For example, the balloon may have a spherical shape. Further, as shown in FIG. 12, the balloon 100 may have a shape in which the length b in the direction perpendicular to the axial direction is larger than the length a in the axial direction. As a result, the surface of the balloon 100 is pressed against the surface of the heart chamber at the base of the pulmonary vein, and the balloon 100 does not enter the blood vessel. Therefore, the surface of the heart chamber can be reliably cauterized without cauterizing the inside of the blood vessel. In this case, since the base member 41 of the electrode portion 40 is greatly curved on the tip side of the maximum diameter-expanded portion of the balloon 100, it is necessary to be more flexible than the balloon 100 in order to prevent buckling deformation and the like.

This application is based on Japanese Patent Application No. 2018-052492 filed on March 20, 2018, and the disclosure contents thereof are referred to and incorporated as a whole.

10 Medical device 11 Guide wire 12 Power supply part 20 Balloon catheter 21 Shaft part 22 Balloon 23 Hub 25 Outer tube 26 Inner tube 27 Guide wire lumen 28 Expansion lumen 30 Outermost sheath body 31 Tip member 32 Connection part 33 Connection line 40 Electrode part 41 Base member 42 Pressure-sensitive conductive member 42a Insulation material matrix 42b Conductive particles 43 Adhesive layer 44 Insulation layer 45 Tip fixing member 60 Living cavity 61 Opening 62 Living wall

Claims (12)

A medical device that is inserted into the living body cavity and ablates living tissue.
With a long shaft
It has an electrode portion arranged at the tip portion of the shaft portion and
The electrode portion has a pressure-sensitive conductive member that produces conductivity by being pressurized or compressed, and a base member that is deformable in the radial direction and has conductivity and a voltage is applied.
A medical device in which at least a part of the surface of the base member on the biological tissue side is covered with the pressure-sensitive conductive member. The medical device according to claim 1, wherein the pressure-sensitive conductive member is an elastic body of an insulating material containing conductive particles. The medical device according to claim 1 or 2, wherein the pressure-sensitive conductive member and the base member are joined via an adhesive layer in a part of the region, and at least a part of the region is in direct contact with each other. The medical device according to claim 1 or 2, wherein the pressure-sensitive conductive member and the base member are joined via a conductive adhesive layer. The medical device according to any one of claims 1 to 4, wherein the base member is a region other than the region where the pressure-sensitive conductive member is provided, which is covered with an insulating layer. Any one of claims 1 to 5, wherein the electrode portion is deformable in the radial direction of the living body cavity, and the pressure-sensitive conductive member is arranged in a region on the tip end side of a portion having a maximum diameter of the base member. The medical device according to item 1. The medical device according to any one of claims 1 to 4, wherein the pressure-sensitive conductive member is provided over a substantially overall length in the length direction of the base member. The medical device according to any one of claims 1 to 7, wherein the base member is a wire rod, and the pressure-sensitive conductive member is provided on at least a part of the outer peripheral side of the base member. The medical device according to claim 8, wherein the medical device has a balloon catheter provided with a balloon at the tip of the shaft portion, the base member is arranged around the balloon, and the base member is deformed by expansion of the balloon. It has a balloon catheter provided with a balloon at the tip of the shaft portion, and the base member has elasticity and is joined to the surface of the balloon, and the base member is attached to at least a part of the outer peripheral side of the base member. The medical device according to any one of claims 1 to 7, wherein the pressure-sensitive conductive member is provided. Claims that the balloon catheter is provided at the tip of the shaft portion, the balloon is the conductive base member, and the pressure-sensitive conductive member is provided on at least a part of the outer surface of the balloon. The medical device according to any one of 1 to 7. The base member is fixed to the outermost sheath body whose tip end is provided on the shaft portion and whose base end portion is provided on the outer peripheral side of the shaft portion, and the shaft portion is the base end with respect to the outermost sheath body. The medical device according to any one of claims 1 to 7, wherein the base member is deformed by moving it to the side.

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