medical devices

Abstract

To provide a medical device that hardly breaks and is high in safety, in which an expansion body is contracted smoothly and can be stored in an external cylinder, and provide an application method thereof.SOLUTION: A medical device 10 includes an expansion body 21 that can be expanded and contracted in a radial direction, a long-sized shaft part 31 having a tip part to which the base end of the expansion body 21 is fixed, and an extension mechanism connected directly or indirectly to the expansion body 21 through the inside of the shaft part 31. The expansion body 21 includes a concave part 56 recessed inside in a radial direction for defining a reception space capable of receiving a biological tissue when the expansion body 21 is expanded, a tip side convex part 57 disposed on a tip side with respect to the concave part 56, which protrudes outside in the radial direction, and a base end side convex part 55 disposed on a base end side with respect to the concave part 56, which protrudes outside in the radial direction. The extension mechanism extends at least the tip side convex part 57 of the expansion body 21 in a tip direction, or contracts it in the radial direction.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a medical device having an expandable body that expands in vivo. Su Regarding. [Background technology]

[0002] In recent years, devices equipped with an expandable body have been used that are inserted into biological lumens such as blood vessels. The expandable body is housed in an outer tube and transported to a target location such as a lesion while in a contracted state. The expandable body is then released from the outer tube at the target location and expands. The expandable body can be used for various purposes, such as dilating or closing lumens or holes. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] U.S. Patent No. 3,645,399 Summary of the Invention [Problem to be solved by the invention]

[0004] When storing the expandable body in the outer tube, it may be difficult because the expandable body is hard. In this case, if you try to store it forcibly, the expandable body or the outer tube may be damaged, which may cause injury to the human body or interfere with smooth treatment.

[0005] For example, Patent Document 1 describes a device in which the distal end opening of the outer tube that houses the expandable body is formed to expand smoothly, allowing the expandable body to be smoothly housed in the outer tube. However, even with this configuration, the expandable body is still contracted by being forcibly housed in the outer tube, so the reduction in the burden on the expandable body and the outer tube is limited.

[0006] The present invention has been made to solve the above-mentioned problems, and provides a medical device in which an expandable body can be smoothly contracted and stored in an outer tube, and which is not easily broken and is highly safe. SuThe purpose is to provide. [Means for solving the problem]

[0007] The medical device according to the present invention, which achieves the above-mentioned object, comprises an expandable body that is radially expandable and contractable and that can self-expand radially to a deployed form by its own restoring force; a long shaft portion having a tip portion to which the base end of the expandable body is fixed; and an extension mechanism that passes through the inside of the shaft portion and is directly or indirectly connected to the expandable body, wherein the expandable body has a recess that is recessed radially inward and defines an acceptance space that can accept biological tissue when the expandable body is expanded, a tip-side convex portion that is located distal to the recess and protrudes radially outward, and a base-side convex portion that is located proximal to the recess and protrudes radially outward, and the extension mechanism extends from the base end of the expandable body toward the tip along the central axis of the expandable body, and is configured to extend from the base end of the expandable body toward the tip, and is configured to extend from the shaft to the expandable body. Department and a pressing portion connected to the operating shaft on the base end side of the tip end of the expansion body and capable of pressing the tip end of the expansion body from the base end side to press the expansion body toward the tip end.By moving the operating shaft toward the tip end relative to the expansion body in its expanded form and pressing the tip end of the expansion body toward the tip end with the pressing portion, an axial pulling force is applied to the expansion body, causing the expansion body in its expanded form to extend toward the tip end, and both the base end convex portion and the tip end convex portion contract radially. [Effects of the Invention]

[0009] In a medical device configured as described above, the expansion body can be extended distally or contracted radially using the extension mechanism, reducing the load on the expansion body and the outer tube when storing the expansion body in the outer tube. As a result, this medical device allows the expansion body to be smoothly contracted and stored in the outer tube, and is highly safe and resistant to breakage.

[0010] The extension mechanism may include an actuation shaft extending from the proximal end of the expansion body toward the distal end along the central axis of the expansion body, and a pressing unit connected to the actuation shaft on the proximal side of the distal end of the expansion body and abutting against the distal end of the expansion body from the proximal side to press the expansion body toward the distal end. In this way, by moving the actuation shaft toward the distal end, the distal end of the expansion body can be moved toward the distal end by the pressing unit, and the expansion body can be extended in the distal direction.

[0011] The pressing portion may be spaced toward the base end from a position where it presses the distal end portion of the expansion body from the base end side when the expansion body is in a fully contracted state. When the base-end convex portion of the expansion body is contracted radially, the pressing portion may be further toward the base end from the position where it presses the tip end portion of the expansion body from the base end side than the amount of movement of the tip end portion of the expansion body toward the base end that accompanies the radial expansion of the base-end convex portion.

[0012] The extension mechanism is The aforementioned an inner tube connected to the distal end portion and extending beyond the distal end portion of the expansion body toward the proximal end side; have , The actuation shaft extending along the central axis of the expandable body from the proximal end of the expandable body to at least the interior of the inner tube; The pressing portion is The inner tube is connected to the actuation shaft at a position closer to the base end than the inner tube. And, The expandable body is brought into contact with the proximal end of the inner tube from the proximal end side and is inserted through the inner tube. The tip of It is possible to press the tip t In this way, by moving the actuation shaft in the distal direction, the pushing portion indirectly pushes the distal end of the expandable body via the inner tube, causing the expandable body to extend in the distal direction and contract in the radial direction.

[0013] The extension mechanism is connected to the actuation shaft on the distal side of the extension body. The aforementioned The expansion body may further include a traction unit that contacts the distal end of the expansion body from the distal side and can pull the distal end of the expansion body in a proximal direction relative to the proximal end of the expansion body. This allows the expansion body to be expanded in the radial direction by pulling the actuation shaft in the proximal direction. In other words, the extension mechanism can also serve as a traction mechanism for expanding the expansion body.

[0014] In a state in which the base-end side convex portion of the expandable body is expanded in the radial direction, the traction portion may be spaced further away from the distal end portion of the expandable body toward the distal end side than the amount of distal end direction movement of the distal end portion of the expandable body caused by radial contraction of the base-end side convex portion. .

[0015] The medical device has an operation section to which a base end of the shaft section is connected. ,before The operating unit may include a repulsive mechanism capable of accumulating a repulsive force by moving the actuating shaft toward the proximal end, a limiting mechanism that limits axial movement of the actuating shaft, and a release mechanism that releases the restriction imposed by the limiting mechanism to allow the actuating shaft to move toward the distal end using the accumulated repulsive force. This allows the actuating shaft to be moved toward the proximal end to expand the expandable body by accumulating a repulsive force in the repulsive mechanism and holding it with the limiting mechanism, and then releasing the accumulated repulsive force with the release mechanism to move the actuating shaft toward the distal end. In other words, the medical device accumulates energy generated when expanding the expandable body and uses that energy to easily extend the expandable body toward the distal end or easily contract it radially.

[0016] The medical device may further include an electrode provided along the recess so as to face the receiving space. This allows the medical device to place biological tissue in the recess and expand the expandable body by sandwiching the biological tissue between the distal convex portion and the proximal convex portion. Therefore, cauterization with the electrode can be performed in a state in which a lumen or hole in the body is expanded to a desired size by the expandable body. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a front view showing the overall configuration of a medical device according to an embodiment of the present invention. [Figure 2] FIG. 10 is an enlarged perspective view of the medical device near the expandable body. [Figure 3] FIG. 1 is a cross-sectional view of a medical device near an expandable body. [Figure 4] FIG. 10 is an explanatory diagram showing a state in which an expandable body is placed in a through-hole in the atrial septum, with the medical device shown in a front view and the biological tissue shown in a cross-sectional view. [Figure 5] FIG. 10 is a cross-sectional view showing the state in which the balloon is inserted into the atrial septum. [Figure 6] FIG. 10 is a cross-sectional view showing the state in which the tip of the medical device is inserted into the atrial septum. [Figure 7] FIG. 10 is a cross-sectional view showing a state in which the distal convex portion of the expandable body is exposed on the left atrium side. [Figure 8] FIG. 10 is a cross-sectional view showing a state in which the distal convex portion of the expandable body is deployed on the left atrium side. [Figure 9] FIG. 10 is a cross-sectional view showing the state in which the expansion body is placed in the atrial septum. [Figure 10] FIG. 10 is a cross-sectional view showing the state in which the expandable body is expanded in the atrial septum. [Figure 11] FIG. 10 is a cross-sectional view showing the expandable body returned from the expanded form to the deployed form. [Figure 12] This is a cross-sectional view to explain an example of a method for storing the expandable body in the outer tube, where (A) shows the state in which the base-end convex portion is stored in the outer tube, (B) shows the state in which the tip-end convex portion has been extended in the axial direction by the extension mechanism, and (C) shows the state in which the entire expandable body is stored in the outer tube. [Figure 13] This is a cross-sectional view to explain another example of a method for accommodating the expandable body in the outer tube, where (A) shows the state in which the expandable body is extended in the axial direction by the extension mechanism, (B) shows the state in which the base-end convex portion is accommodated in the outer tube, and (C) shows the state in which the entire expandable body is accommodated in the outer tube. [Figure 14] This is a plan view showing the tip portion of a medical device according to a first variant example, with the expansion body visible; (A) shows the expansion body in an expanded state, and (B) shows the expansion body in an axially extended state. [Figure 15] 10A and 10B are cross-sectional views showing the distal end of a medical device according to a second modification, in which (A) shows the expandable body in a deployed state, and (B) shows the expandable body in an axially extended state. [Figure 16] 10A and 10B are cross-sectional views showing the distal end of a medical device according to a third modified example, in which (A) shows the expandable body in a deployed state, and (B) shows the expandable body in an axially extended state. [Figure 17] 10A and 10B are cross-sectional views showing the distal end of a medical device according to a fourth modification, in which (A) shows the expandable body in a deployed state, and (B) shows the expandable body in an axially extended state. [Figure 18]10A and 10B are cross-sectional views showing the distal end of a medical device according to a fifth modified example, in which (A) shows the expandable body in a deployed state, and (B) shows the expandable body in an axially extended state. [Figure 19] A cross-sectional view showing the tip of a medical device relating to the sixth variant, where (A) shows the state in which the expansion body is deployed, (B) shows the state in which the expansion body is contracted radially, and (C) shows the state in which the entire expansion body is housed in the outer tube. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, embodiments 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 a medical device that is inserted into a body lumen will be referred to as the "distal side," and the side that is operated will be referred to as the "proximal side."

[0021] As shown in Figure 4, the medical device 10 of this embodiment is configured to expand a through hole Hh formed in the atrial septum HA of a patient's heart H, and to perform a maintenance procedure to maintain the expanded through hole Hh at that size.

[0022] 1, the medical device 10 of this embodiment has a long section 20 extending from the base end to the tip, an expansion body 21 provided at the tip end of the long section 20, and an operation section 23 provided at the base end of the long section 20. The expansion body 21 is provided with an energy transmission element 22 for performing the maintenance treatment described above.

[0023] As shown in Figures 1 to 3, the long portion 20 has a shaft portion 31 that holds the expansion body 21 at its tip, an outer tube 30 that houses the shaft portion 31, an operating shaft 33, a traction portion 35 that is fixed to the tip of the operating shaft 33, and a pressing portion 34 that is fixed to the base end side of the traction portion 35 of the operating shaft 33.

[0024] The shaft portion 31 is a long tubular body extending from the operation portion 23 to the expansion body 21. The base end of the shaft portion 31 is fixed to the tip end of the operation portion 23. The tip end of the shaft portion 31 is fixed to the base end of the expansion body 21.

[0025] The outer tube 30 is a long tubular body that covers the shaft portion 31 and is movable back and forth in the axial direction (toward the axis of the long portion 20) relative to the shaft portion 31. The outer tube 30 can house the contracted expandable body 21 inside when it is moved toward the distal end of the long portion 20. When the expandable body 21 is housed inside the outer tube 30, the expandable body 21 can be exposed by moving the outer tube 30 toward the proximal end.

[0026] The actuation shaft 33 is a long tubular body disposed inside the shaft portion 31, and is movable back and forth in the axial direction relative to the shaft portion 31. The actuation shaft 33 protrudes distally from the distal end of the shaft portion 31, and protrudes distally from the distal end of the expandable body 21. The distal end of the actuation shaft 33, which is located distally of the expandable body 21, is fixed to the traction unit 35. The proximal end of the actuation shaft 33 is led out proximally from the operation unit 23. A guidewire lumen is formed inside the actuation shaft 33 along the axial direction, and a guidewire 11 (see Figures 4 to 13) can be inserted therethrough.

[0027] The traction portion 35 is an annular member fixed to the outer peripheral surface of the tip of the actuation shaft 33, and protrudes radially outward from the outer peripheral surface of the actuation shaft 33. The traction portion 35 is not fixed to the expandable body 21. The outer diameter of the traction portion 35 is larger than the inner diameter of the tip of the expandable body 21. Therefore, the traction portion 35 abuts against the tip of the expandable body 21 from the tip side and pulls the expandable body 21 in the proximal direction, thereby applying a compressive force to the expandable body 21.

[0028] The pressing portion 34 is an annular member fixed to the outer peripheral surface of the actuation shaft 33 on the base end side relative to the traction portion 35, and protrudes radially outward from the outer peripheral surface of the actuation shaft 33. The pressing portion 34 is not fixed to the expandable body 21. The pressing portion 34 is disposed inside the expandable body 21, and is disposed closer to the base end than the tip end of the expandable body 21. The outer diameter of the pressing portion 34 is larger than the inner diameter of the tip end of the expandable body 21. Therefore, the pressing portion 34 abuts against the tip end of the expandable body 21 from the base end side and presses the expandable body 21 toward the tip end, thereby applying an axial pulling force to the expandable body 21.

[0029] Furthermore, when storing the expansion body 21 in the outer tube 30, by moving the traction portion 35 away from the expansion body 21 toward the tip side, the expansion body 21 can be easily moved in the axial direction, improving storage properties.

[0030] The operating unit 23 has a housing 40 that is held by the surgeon, a dial 41 that can be rotated by the surgeon, a conversion mechanism 42 that converts the rotation of the dial 41 into axial movement, a repulsion mechanism 43 that can accumulate a repulsive force against the movement of the operating shaft 33, a restriction mechanism 44 that restricts the rotation of the dial 41, and a release mechanism 45 that releases the restriction imposed by the restriction mechanism 44.

[0031] The dial 41 is connected to the housing 40 so as to be rotatable on a plane perpendicular to the axes of the shaft portion 31 and the actuation shaft 33. A portion of the dial 41 is exposed to the outside through an opening in the housing 40 so that it can be operated by the surgeon.

[0032] The conversion mechanism 42 is configured, for example, with a ball screw structure including a screw shaft 46 fixed to the base end of the actuation shaft 33, a nut 47 fixed to the dial 41, and balls (not shown) arranged in a screw groove 48 on the outer circumferential surface of the screw shaft 46 inside the nut 47. When the nut 47 rotates together with the dial 41, a force acts on the screw shaft 46 along the axial direction, causing the screw shaft 46 to move toward the distal end or proximal end without rotating. Note that the configuration of the conversion mechanism 42 is not limited to this.

[0033] The repulsion mechanism 43 is, for example, a spring, and is disposed between the base end surface of the screw shaft 46 and the inner wall surface of the housing 40. The repulsion mechanism 43 can accumulate a compressive force (repulsive force) as the screw shaft 46 moves toward the base end. Note that the repulsion mechanism 43 is not limited to a spring, and may be, for example, an elastic body such as rubber, an air cylinder, or the like.

[0034] The limiting mechanism 44 limits the rotation of the dial 41, thereby limiting the axial movement of the actuation shaft 33. The limiting mechanism 44 is, for example, a limiting member 49 that is disposed in a retaining hole 40A that penetrates the housing 40 near the dial 41 and that comes into contact with the dial 41 to limit the rotation of the dial 41 by frictional force. Note that the configuration of the limiting mechanism 44 is not limited to this.

[0035] The release mechanism 45 is composed of a holding hole 40A that movably holds the limiting mechanism 44. The surgeon can move the limiting member 49 away from the dial 41 along the holding hole 40A. This allows the dial 41 to rotate with little resistance, and the repulsive force accumulated in the repulsion mechanism 43 causes the dial 41 to rotate while the screw shaft 46 and the actuation shaft 33 move toward the distal end.

[0036] 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. The number of wire portions 50 is not particularly limited. Each wire portion 50 can expand and contract in the radial direction of the expandable body 21. In a natural state where no external force is applied, the expandable body 21 is in a radially expanded form. The base end of each wire portion 50 is fixed to the distal end of the shaft portion 31. The distal ends of each wire portion 50 are gathered at a ring-shaped gathering portion 54, which is the distal end of the expandable body 21. The wire portions 50 are inclined radially from both axial ends of the expandable body 21 toward the center. Furthermore, the wire portion 50 has a valley-shaped clamping portion 51 at the axial center in the radial direction of the expandable body 21.

[0037] Each wire portion 50 has a base-side convex portion 55, a recessed portion 56, and a distal-side convex portion 57. The base-side convex portion 55 is located on the base-side side of the recessed portion 56 and is formed to have a convex shape extending radially outward. The distal-side convex portion 57 is located on the distal side of the recessed portion 56 and is formed to have a convex shape extending radially outward. A base-side clamping portion 52 is formed at the distal end of the base-side convex portion 55, and a distal-side clamping portion 53 is formed at the base end of the distal-side convex portion 57. The base-side clamping portion 52, recessed portion 56, and distal-side clamping portion 53, which are aligned in the axial direction, form a valley-shaped clamping portion 51 in the radial direction of the expandable body 21. The recessed portion 56 is located between the base-side clamping portion 52 and the distal-side clamping portion 53 and is recessed radially inward, defining a receiving space that can receive biological tissue when the expandable body 21 is expanded. In the deployed configuration, the distance between the base-side clamping portion 52 and the tip-side clamping portion 53 is preferably somewhat larger in the axial direction on the outer side than on the inner side in the radial direction, which makes it easy to place biological tissue between the base-side clamping portion 52 and the tip-side clamping portion 53 from the outer side in the radial direction.

[0038] The distal convex portion 57 has one distal through-hole 60 formed near the apex that protrudes most radially in the deployed state. The distal through-hole 60 penetrates the expandable body 21 in the radial direction. This reduces the bending rigidity of the distal convex portion 57. Therefore, the distal convex portion 57 is easily deformed to become convex outward in the radial direction, and is also easily deformed so that the convex shape becomes flat.

[0039] The distal clamping unit 53 has a backrest 62 formed thereon, which protrudes from the recess 56 toward the apex of the distal convex portion 57 so as to be disposed in the distal through-hole 60. The backrest 62 is in the form of a cantilever with a fixed base end, and is therefore easily bent. Therefore, the backrest 62 can be easily bent by a force acting toward the distal end from the energy transmission element 22 disposed in the proximal clamping unit 52. The distal through-hole 60 and the backrest 62 do not necessarily have to be provided.

[0040] In the deployed configuration, the proximal clamping portion 52 has the energy transmission element 22 disposed on the surface facing the distal end side.

[0041] Since the energy transmission element 22 is provided on the proximal clamping unit 52, when the clamping unit 51 clamps the atrial septum HA, energy from the energy transmission element 22 is transmitted to the atrial septum HA from the right atrium side. Note that when the energy transmission element 22 is provided on the distal clamping unit 53, energy from the energy transmission element 22 is transmitted to the atrial septum HA from the left atrium side.

[0042] The energy transfer elements 22 are configured, for example, with bipolar electrodes that receive electrical energy from an external energy supply device (not shown). In this case, electricity is passed between the energy transfer elements 22 arranged in each wire portion 50. The energy transfer elements 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 elongated portion 20 and the operating portion 23 and connected to the energy supply device.

[0043] Alternatively, the energy transfer element 22 may be configured as a monopolar electrode. In this case, current is passed between the energy transfer element 22 and a return electrode plate prepared outside the body. Alternatively, the energy transfer element 22 may be a heat-generating element (electrode tip) that receives high-frequency electrical energy from an energy supply device and generates heat. In this case, current is passed between the energy transfer elements 22 arranged in each wire portion 50. Furthermore, the energy transfer element 22 may be configured as an element capable of applying energy to the through-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.

[0044] In this embodiment, the energy transmission element 22 is provided in the base end clamping portion 52 and the back support portion 62 is provided in the tip end clamping portion 53, but the energy transmission element 22 may also be provided in the tip end clamping portion 53 and the back support portion 62 may also be provided in the base end clamping portion 52.

[0045] 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 forming the expandable body 21 may have dimensions outside these ranges. Furthermore, the shape of the wire portion 50 is not limited, and may have, for example, a circular cross-sectional shape or other cross-sectional shapes.

[0046] The wire portion 50 can be made of a metal material. Examples of such metal materials include titanium-based alloys (Ti-Ni, Ti-Pd, Ti-Nb-Sn, etc.), copper-based 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 wire portion 50 is not limited to these, and other materials may also be used.

[0047] The outer cylinder 30 and shaft portion 31 of the long portion 20 are preferably formed from a material having a certain degree of flexibility. Examples of such materials include polyolefins such as polyethylene, polypropylene, polybutene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ionomer, and mixtures 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.

[0048] The actuation shaft 33 can be formed from a long wire rod made of, for example, a superelastic alloy such as a nickel-titanium alloy or a copper-zinc alloy, a metal material such as stainless steel, a resin material with relatively high rigidity, etc. Alternatively, the actuation shaft 33 may be formed from the above materials coated with a resin material such as polyvinyl chloride, polyethylene, polypropylene, an ethylene-propylene copolymer, or a fluororesin.

[0049] The pulling portion 35 and the pressing portion 34 can be made of, for example, 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.

[0050] Next, a treatment method using the medical device 10 according to this embodiment will be described. This treatment method is performed on a patient suffering from heart failure (left ventricular failure). More specifically, as shown in Fig. 4, this is a treatment method performed on a patient suffering from chronic heart failure in which the blood pressure in the left atrium HLa increases due to hypertrophy of the myocardium of the left ventricle of the heart H and increased stiffness.

[0051] When forming the through-hole Hh, the surgeon delivers an introducer, which is a combination of a guiding sheath and a dilator, to the vicinity of the interatrial septum HA. The introducer can be delivered to the right atrium HRa, for example, via the inferior vena cava IV. The introducer can also 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] The surgeon passes a puncture device (not shown) and a dilator from the right atrium HRa side toward the left atrium HLa side to form a through-hole Hh. The puncture device is passed through the dilator and delivered to the atrial septum HA.

[0053] Next, the surgeon delivers the balloon catheter 150 to the vicinity of the atrial septum HA along the pre-inserted guide wire 11. As shown in FIG. 5, the balloon catheter 150 has a balloon 152 at the tip of a shaft portion 151. Once the balloon 152 is positioned in the atrial septum HA, it is expanded radially to push open the through-hole Hh. During this process, due to the influence of the fibers of the septal tissue, the through-hole Hh expands to a diameter equal to the maximum diameter of the expanded balloon 152 in the direction along the fibers, but is difficult to expand in other directions, resulting in an elongated shape.

[0054] Next, the medical device 10 is delivered near the atrial septum HA, and the expandable body 21 is positioned at the through-hole Hh. A guidewire is not used when delivering the medical device 10, but a guidewire may be used for stable operation under pulsation. At this time, the distal end of the medical device 10 penetrates the atrial septum HA and reaches the left atrium HLa. As shown in FIG. 6 , when the medical device 10 is inserted, the expandable body 21 is in a contracted state housed in the outer tube 30. The through-hole Hh is expanded by the balloon 152, allowing the outer tube 30 to be inserted through the through-hole Hh. In the contracted state, the base-side convex portion 55, the concave portion 56, and the distal-side convex portion 57, which are curved in the expanded state, are deformed to a nearly flat shape, causing the expandable body 21 to contract radially. In the initial state of the medical device 10 (the state in which the expandable body 21 is housed in the outer tube 30 and is fully contracted), the pressing portion 34 is spaced somewhat from the collection portion 54 (tip portion) of the expandable body 21 toward the base end.

[0055] Next, as shown in Figure 7, the surgeon moves the outer tube 30 toward the proximal end to expose the distal convex portion 57 of the expandable body 21 inside the left atrium HLa. As described above, in the initial state, the pressing portion 34 is spaced some distance toward the proximal end from the collecting portion 54 of the expandable body, so when the distal side of the expandable body 21 is exposed from the outer tube 30, the distal side of the expandable body 21 self-expands slightly until the collecting portion 54 abuts against the pressing portion 34. This makes it possible to position the expandable body 21 by hooking the distal side of the expandable body 21 onto the atrial septum HA.

[0056] As a modified procedure for exposing the distal convex portion 57 of the expandable body 21 in the left atrium HLa, the dial 41 may be rotated from the initial state to move the pressing unit 34 toward the distal end, and the pressing unit 34 may press the collection unit 54 (distal portion) of the expandable body 21 from the proximal end toward the distal end. This applies a pulling force in the axial direction to the expandable body 21. Next, the surgeon moves the outer tube 30 toward the proximal end to expose the distal convex portion 57 of the expandable body 21 in the left atrium HLa. At this time, the pressing unit 34 abuts against the proximal end of the collection unit 54 of the expandable body 21, applying a pulling force in the axial direction to the expandable body 21. Therefore, the shape of the distal convex portion 57 after being released from the outer tube 30 is maintained in a shape close to the flat shape it had when it was housed in the outer tube 30. This reduces friction between the expansion body 21 and the outer tube 30 when the outer tube 30 is moved toward the base end, thereby preventing damage to the expansion body 21 and the outer tube 30 and making it easier to expose the tip-side convex portion 57.

[0057] After the distal convex portions 57 of the expandable body 21 released from the outer tube 30 have self-expanded slightly, the surgeon rotates the dial 41 to move the actuation shaft 33 toward the proximal end relative to the shaft portion 31. This procedure is performed to completely self-expand the distal convex portions 57 of the expandable body 21, which have not yet fully self-expanded. The surgeon moves the actuation shaft 33 toward the proximal end until the pressing portion 34 moves away from the collecting portion 54 toward the proximal end. As a result, as shown in FIG. 8 , the distal convex portions 57 are released from the pulling force received from the pressing portion 34 and expand radially within the left atrium HLa due to their own restoring force. Note that when exposing the distal convex portions 57 within the left atrium HLa, it is not necessary for the pressing portion 34 to apply a pulling force in the axial direction to the expandable body 21.

[0058] Next, as shown in FIG. 9 , the surgeon moves the outer tube 30 toward the proximal end relative to the shaft portion 31. This causes the proximal convex portion 55 of the expandable body 21 to expand radially within the right atrium HRa due to its own restoring force. As a result, the entire expandable body 21 expands due to its own restoring force and returns to its original expanded configuration or a configuration close to the expanded configuration. The concave portion 56 is positioned inside the through-hole Hh. At this time, the atrial septum HA is positioned between the proximal clamping portion 52 and the distal clamping portion 53. In the tissue clamping direction, the atrial septum HA is positioned between the energy transmission element 22 and the back support portion 62. Note that the expandable body 21 may not completely return to the expanded configuration due to contact with the through-hole Hh, but may return to a configuration close to the expanded configuration. In this state, the expandable body 21 is not covered by the outer tube 30 and is not receiving force from the actuation shaft 33. This configuration of the expandable body 21 can also be defined as being included in the expanded configuration.

[0059] When the base-side convex portion 55 of the expandable body 21 expands radially, the collection portion 54 moves toward the base end. At this time, the pressing portion 34 is farther away from the collection portion 54 toward the base end than the movement of the collection portion 54, so the moving collection portion 54 does not reach the pressing portion 34. Therefore, the expansion of the expandable body 21 in the radial direction is not hindered by the pressing portion 34.

[0060] Next, with the biological tissue received in the receiving space defined by the recess 56, the surgeon operates the dial 41 of the operating unit 23 to move the actuation shaft 33 toward the proximal end, as shown in FIGS. 1 and 10 . This causes the traction unit 35, fixed to the distal end of the actuation shaft 33, to abut against the assembly 54 of the expansion body 21 from the distal end, pulling the assembly 54 toward the proximal end. As a result, the expansion body 21 is pulled in the compression direction by the traction unit 35, and is compressed in the axial direction. The atrial septum HA is clamped between the proximal clamping unit 52 and the distal clamping unit 53, and the energy transmission element 22 is pressed against the biological tissue. At this time, the energy transmission element 22 and the backrest 62 face each other. By rotating the dial 41 of the operating unit 23, the screw shaft 46 moves toward the proximal end, compressing the repulsion mechanism 43. This causes a repulsion force to accumulate in the repulsion mechanism 43. The rotational position of the dial 41 is maintained by the limiting mechanism 44.

[0061] After the through-hole Hh is expanded, the surgeon checks the hemodynamics. As shown in FIG. 4, the surgeon delivers the hemodynamics checking device 100 to the right atrium HRa via the inferior vena cava IV. A known echo catheter, for example, can be used as the hemodynamics checking device 100. The surgeon can display the echo image acquired by the hemodynamics checking device 100 on a display or other display device, and check the amount of blood passing through the through-hole Hh based on the display results. Note that the hemodynamics may be checked after the through-hole Hh is expanded by the balloon 152.

[0062] Next, the surgeon performs a maintenance procedure to maintain the size of the through-hole Hh. In the maintenance procedure, in the state shown in FIG. 10 , energy is applied to the edge of the through-hole Hh through the energy transmission element 22, thereby cauterizing (heating and cauterizing) the edge of the through-hole Hh with the energy. When the biological tissue near the edge of the through-hole Hh is cauterized through the energy transmission element 22, a degenerated portion is formed near the edge where the biological tissue is degenerated. Because the biological tissue in the degenerated portion loses its elasticity, the through-hole Hh can maintain the shape it had when it was expanded by the expandable body 21.

[0063] After the maintenance procedure, the surgeon checks the hemodynamics again. If the amount of blood passing through the through-hole Hh is the desired amount, the surgeon operates the release mechanism 45 of the operation unit 23 to release the restriction on rotation of the dial 41 imposed by the restriction mechanism 44, as shown in FIG. 1. This causes the repulsion mechanism 43 to extend axially due to the accumulated force, rotating the dial 41 and moving the screw shaft 46 toward the distal end. This causes the traction portion 35 of the actuation shaft 33 to move distally and separate from the expandable body 21, causing the expandable body 21 to contract radially, as shown in FIG. 11. As a result, the expandable body 21 transitions from the expanded form to the deployed form, which is its natural state.

[0064] Next, the surgeon contracts the expandable body 21 in the radial direction and stores it in the outer tube 30. An example of the procedure for this is shown in FIG. 12. First, as shown in FIG. 12(A), the surgeon moves the outer tube 30 toward the distal end relative to the shaft portion 31. As a result, the base-end convex portion 55 of the expandable body 21 contracts in the radial direction and is stored in the outer tube 30. As a result, the collecting portion 54 of the expandable body 21 moves toward the distal end, but because the traction portion 35 is farther away from the collecting portion 54 toward the distal end than the movement of the collecting portion 54, the moving collecting portion 54 does not reach the traction portion 35. Therefore, the radial contraction of the expandable body 21 is not hindered by the traction portion 35.

[0065] Next, the surgeon rotates the dial 41 of the operation unit 23 to move the actuation shaft 33 toward the distal end relative to the shaft portion 31. As a result, as shown in Figure 12(B), the pressing portion 34 fixed to the actuation shaft 33 comes into contact with the assembly portion 54 of the expandable body 21 from the base end side and presses it toward the distal end. As a result, the assembly portion 54 of the expandable body 21 moves toward the distal end, applying a pulling force in the axial direction to the expandable body 21 and causing the distal-side convex portion 57 to contract radially.

[0066] Next, the surgeon moves the outer tube 30 toward the distal end relative to the shaft portion 31. As a result, as shown in FIG. 12(C), the distal convex portion 57 of the expandable body 21 contracts radially and is housed in the outer tube 30. As a result, the entire expandable body 21 is housed in the outer tube 30. At this time, the collecting portion 54 moves toward the distal end, but because the traction portion 35 is located farther away from the collecting portion 54 toward the distal end than the movement of the collecting portion 54, the moving collecting portion 54 does not reach the traction portion 35. Therefore, the radial contraction of the expandable body 21 is not hindered by the traction portion 35.

[0067] When the distal protrusion 57 of the expandable body 21 begins to be retracted into the outer tube 30, as shown in FIG. 12(B), the pressing portion 34 abuts against the proximal end of the assembly portion 54 of the expandable body 21, applying a pulling force in the axial direction to the expandable body 21, causing the recess 56 and the distal protrusion 57 to become flatter. That is, before the axial pulling force is applied to the expandable body 21, the distal clamping portion 53 (see FIG. 12(A)) stands at an angle close to a right angle to the axial direction, but now tilts toward an angle close to parallel to the axial direction. That is, the distal protrusion 57 is contracted to a certain extent in the radial direction. This reduces friction between the distal clamping portion 53 and the outer tube 30 when the distal protrusion 57 is retracted into the outer tube 30, as shown in FIG. 12(C). This reduces damage to the expandable body 21 and the outer tube 30 and facilitates retraction of the distal protrusion 57. Here, the radial contraction of the tip-side convex portion 57 is performed in two stages: by the action of the extension mechanism formed by the actuation shaft 33 and the pressing portion 34, and by compression by the outer cylinder 30. However, the radial contraction of the tip-side convex portion 57 may be performed only by the action of the extension mechanism.

[0068] The procedure for radially contracting the expandable body 21 in the deployed form and storing it in the outer tube 30 is not limited to the procedure shown in Fig. 12. Fig. 13 shows another example of the procedure. The surgeon rotates the dial 41 of the operation unit 23 to move the actuation shaft 33 toward the distal end relative to the shaft portion 31. As a result, as shown in Fig. 13(A), the pressing portion 34 fixed to the actuation shaft 33 abuts against the collective portion 54 of the expandable body 21 from the proximal end side and presses it toward the distal end. As a result, the collective portion 54 of the expandable body 21 moves toward the distal end, applying a pulling force in the axial direction to the expandable body 21, causing both the proximal-side convex portion 55 and the distal-side convex portion 57 to contract radially.

[0069] Next, as shown in Figure 13(B), the surgeon moves the outer tube 30 toward the distal end relative to the shaft portion 31. As a result, the base-end convex portion 55 of the expandable body 21 contracts radially and is housed in the outer tube 30. As a result, the collecting portion 54 of the expandable body 21 moves toward the distal end, but because the traction portion 35 is farther away from the collecting portion 54 toward the distal end than the movement of the collecting portion 54, the moving collecting portion 54 does not reach the traction portion 35. Therefore, the radial contraction of the expandable body 21 is not hindered by the traction portion 35.

[0070] Furthermore, when the distal convex portion 57 of the expandable body 21 begins to be retracted into the outer tube 30, as shown in Fig. 13(A), the pressing portion 34 abuts against the proximal end of the assembly portion 54 of the expandable body 21, and a pulling force in the axial direction acts on the expandable body 21, causing the shape of the proximal convex portion 55 to approach a flat shape. As a result, as shown in Fig. 13(B), when the proximal convex portion 55 is retracted into the outer tube 30, friction between the proximal convex portion 55 and the outer tube 30 is reduced. This makes it possible to prevent damage to the expandable body 21 and the outer tube 30 and to facilitate retraction of the proximal convex portion 55.

[0071] Next, the surgeon moves the outer tube 30 toward the distal end relative to the shaft portion 31. As a result, as shown in FIG. 13(C), the distal convex portion 57 of the expandable body 21 contracts radially and is housed in the outer tube 30. As a result, the entire expandable body 21 is housed in the outer tube 30. At this time, the collecting portion 54 moves toward the distal end, but because the traction portion 35 is farther away from the collecting portion 54 toward the distal end than the movement of the collecting portion 54, the moving collecting portion 54 does not reach the traction portion 35. Therefore, the radial contraction of the expandable body 21 is not hindered by the traction portion 35.

[0072] 13(B), after the base-side convex portion 55 has been housed in the outer tube 30, but before the distal-side convex portion 57 has been housed in the outer tube 30, as shown in FIG. 13(C), the dial 41 of the operating unit 23 may be rotated as shown in FIG. 12(B) to cause the pressing unit 34 to press the assembly portion 54 of the expandable body 21 toward the distal end. This causes the distal-side convex portion 57 to contract radially, thereby reducing friction between the distal-side clamping portion 53 and the outer tube 30 when the distal-side convex portion 57 is housed in the outer tube 30. This prevents damage to the expandable body 21 and the outer tube 30 and makes it easier to house the distal-side convex portion 57.

[0073] After storing the expandable body 21 in the outer tube 30, the surgeon removes the expandable body 21 from the through-hole Hh. Furthermore, the surgeon removes the entire medical device 10 from the living body, thereby completing the treatment.

[0074] As described above, the medical device 10 of this embodiment comprises an expansion body 21 that can expand and contract radially, a long shaft portion 31 having a tip portion to which the base end of the expansion body 21 is fixed, and an extension mechanism that passes through the inside of the shaft portion 31 and is directly or indirectly connected to the expansion body 21, and the expansion body 21 has a recess 56 that is recessed radially inward and defines a receiving space that can receive biological tissue when the expansion body 21 is expanded, a tip-side convex portion 57 that is positioned distally of the recess 56 and protrudes radially outward, and a base-side convex portion 55 that is positioned proximal to the recess 56 and protrudes radially outward, and the extension mechanism extends at least the tip-side convex portion 57 of the expansion body 21 distally or contracts it radially.

[0075] The medical device 10 configured as described above can use the extension mechanism to extend the expandable body 21 in the distal direction or contract it in the radial direction, thereby reducing the load on the expandable body 21 and the outer tube 30 when storing the expandable body 21 in the outer tube 30. Therefore, the medical device 10 can smoothly contract the expandable body 21 to store it in the outer tube 30, making it less susceptible to breakage and highly safe.

[0076] The extension mechanism also has an actuation shaft 33 that extends from the base end of the expansion body 21 toward the tip along the central axis of the expansion body 21, and a pressing unit 34 that is connected to the actuation shaft 33 on the base end side of the tip end of the expansion body 21 and can abut against the tip end of the expansion body 21 from the base end side to press the expansion body 21 toward the tip. As a result, by moving the actuation shaft 33 toward the tip end, the tip end of the expansion body 21 can be moved toward the tip end by the pressing unit 34, and the expansion body 21 can be extended in the tip direction.

[0077] The extension mechanism also has a traction unit 35 that is connected to the actuation shaft 33 closer to the distal end than the expansion body 21, abuts against the distal end of the expansion body 21 from the distal side, and is capable of pulling the distal end of the expansion body 21 in the proximal direction relative to the proximal end of the expansion body 21. This allows the expansion body 21 to be expanded in the radial direction by pulling the actuation shaft 33 in the proximal direction. In other words, the extension mechanism can also serve as a traction mechanism for expanding the expansion body 21.

[0078] The medical device 10 also has an operating unit 23 to which the proximal end of the shaft portion 31 is connected, and the extension mechanism has an actuation shaft 33 that passes through the inside of the shaft portion 31 and is directly or indirectly connected to the expandable body 21. The operating unit 23 has a repulsion mechanism 43 that can accumulate a repulsive force by moving the actuation shaft 33 toward the proximal end, a limiting mechanism 44 that limits the axial movement of the actuation shaft 33, and a release mechanism 45 that releases the restriction imposed by the limiting mechanism 44 and allows the actuation shaft 33 to move toward the distal end using the accumulated repulsive force. As a result, by moving the actuation shaft 33 toward the proximal end to expand the expandable body 21, a repulsive force can be accumulated in the repulsion mechanism 43 and held by the limiting mechanism 44, and then the accumulated repulsive force can be released by the release mechanism 45 to move the actuation shaft 33 toward the distal end. In other words, the medical device 10 accumulates energy used when expanding the expandable body 21 and uses that energy to easily extend the expandable body 21 toward the distal end or easily contract the expandable body 21 in the radial direction.

[0079] The medical device 10 also has an electrode provided along the recess 56 so as to face the receiving space. This allows the medical device 10 to place biological tissue in the recess 56 and expand the expandable body 21 with the biological tissue sandwiched between the distal convex portion 57 and the proximal convex portion 55. Therefore, cauterization with the electrode can be performed in a state in which a lumen or hole in the body has been expanded to a desired size by the expandable body 21.

[0080] The present invention also provides methods of using the medical device 10. A method of using the medical device 10 is a method of using a medical device 10 having an expansion body 21 that can expand and contract radially, a long shaft portion 31 having a tip portion to which the base end of the expansion body 21 is fixed, and an extension mechanism that passes through the inside of the shaft portion 31 and is directly or indirectly connected to the expansion body 21, wherein the expansion body 21 has a recess 56 that is recessed radially inward and defines a receiving space that can receive biological tissue when the expansion body 21 is expanded, a tip-side convex portion 57 that is positioned distal to the recess 56 and protrudes radially outward, and a base-side convex portion 55 that is positioned proximal to the recess 56 and protrudes radially outward, and the extension mechanism is operated to contract at least the tip-side convex portion 57 of the expansion body 21, and the outer tube 30, through which the shaft portion 31 is inserted and which is positioned proximal to the expansion body 21, is moved distally relative to the expansion body 21 in a state in which the tip-side convex portion 57 is contracted, and the expansion body 21 is stored within the outer tube 30.

[0081] The method of using the medical device 10 configured as described above uses the extension mechanism to contract at least the distal convex portion 57 of the expandable body 21 to store the expandable body 21 in the outer tube 30, thereby reducing the load on the expandable body 21 and the outer tube 30 when storing the expandable body 21 in the outer tube 30. Therefore, the method of using the medical device 10 allows the expandable body 21 to be smoothly contracted and stored in the outer tube 30, is less likely to break, and is highly safe.

[0082] Furthermore, by moving the outer tube 30 toward the distal end relative to the expandable body 21 in which the distal convex portion 57 has been partially contracted by operating the extension mechanism, the distal convex portion 57 may be further contracted and stored within the outer tube 30. As a result, the distal convex portion 57 is contracted by the extension mechanism and then compressed by the outer tube 30. Therefore, the force for contracting the distal convex portion 57 is distributed between the force of the extension mechanism and the force of compression by the outer tube 30, making the storage operation easier.

[0083] 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. For example, as shown in a first modification in FIG. 14(A), the medical device 10 may include an inner tube 70 connected to the distal end of the expandable body 21 and extending proximally beyond the distal end of the expandable body 21, and an outer tube 71 connected to the distal end of the shaft portion 31 and extending distally. An actuation shaft 33 slidably penetrates the inner tube 70 and the outer tube 71. The proximal end of the inner tube 70 is disposed inside the outer tube 71 and is slidable relative to the outer tube 71. The outer tube 71 has a slit 73 extending in the axial direction, and a sliding protrusion 72, which is axially movable along the slit 73, is fixed to the outer surface of the inner tube 70. The sliding protrusion 72 is disposed in the slit 73, thereby limiting the relative circumferential rotation of the inner tube 70 and the outer tube 71. This suppresses twisting of the expandable body 21. The pressing portion 34 connected to the actuation shaft 33 abuts against the base end portion 74 of the inner tube 70 from the base end side, closer to the base end than the inner tube 70, and can press the distal end of the expandable body 21 in the distal direction via the inner tube 70. Therefore, as shown in Figure 14(B) , by moving the actuation shaft 33 in the distal direction, the pressing portion 34 indirectly presses the distal end of the expandable body 21 in the distal direction via the inner tube 70, thereby extending the expandable body 21 in the distal direction and contracting the expandable body 21 in the radial direction.

[0084] 15(A), the extension mechanism may have multiple pressing connectors 36 connecting the actuation shaft 33 and the distal-side protrusions 57. The pressing connectors 36 are rod-shaped members that are difficult to bend so as to easily transmit the pressing force, and are connected to the wire members 50 constituting the distal-side protrusions 57, rather than to the assembly 54 of the expandable body 21. The pressing connectors 36 are connected to the distal-side protrusions 57 at a position that is a certain distance radially outward from the assembly 54. As a result, as shown in FIG. 15(B), by moving the actuation shaft 33 distally, the pressing connectors 36 press the distal-side protrusions 57, thereby extending the expandable body 21 distally and contracting it radially. It is preferable that the pressing connectors 36 be connected to the distal-side protrusions 57 of all of the wire members 50, but they may be connected to only some of the wire members 50. Therefore, the number of the pressing connecting portion 36 may be one or more.

[0085] 16(A), the extension mechanism may have a plurality of pulling wires 80 inserted into the shaft portion 31, and the distal ends of the pulling wires 80 may be led out from the shaft portion 31 and connected to the distal-side convex portions 57. The proximal ends of the pulling wires 80 are led out from the operation unit 23 and can be operated to pull. As a result, as shown in FIG. 16(B), by pulling the pulling wires 80, the distal-side convex portions 57 are pulled toward the central axis of the expandable body 21, thereby contracting the expandable body 21 in the radial direction. Although the pulling wires 80 are preferably connected to the distal-side convex portions 57 of all the wire portions 50, they may also be connected to only some of the wire portions 50. Therefore, the number of pulling wires 80 may be one or more. The pulling wire 80 may have a single proximal end and a plurality of branches at the distal end.

[0086] 17(A), the extension mechanism may have a traction wire 80 inserted into the actuation shaft 33, and the distal end of the traction wire 80 may be led out through the through-hole 37 of the actuation shaft 33 and connected to the distal end-side convex portion 57. As a result, as shown in FIG. 17(B), by pulling the traction wire 80, the distal end-side convex portion 57 is pulled toward the central axis of the expandable body 21, thereby effectively contracting the expandable body 21 in the radial direction. As in the fourth modification, the traction wire 80 may be one or more, and may be branched at the distal end.

[0087] 18(A), the extension mechanism may have a pressing shaft 38 disposed between the shaft portion 31 and the actuation shaft 33 and slidable relative to the shaft portion 31 and the actuation shaft 33, and a pressing portion 34 disposed at the distal end of the pressing shaft 38 may be capable of abutting the assembly portion 54 at the distal end of the expandable body 21 from the proximal end. That is, the medical device 10 has a pressing shaft 38 for radially contracting the expandable body 21, independently of the actuation shaft 33 for radially expanding the expandable body 21. The proximal end of the pressing shaft 38 extends from the operation unit 23 and can be moved in the axial direction. As a result, as shown in FIG. 18(B), by moving the pressing shaft 38 distally, the assembly portion 54 of the expandable body 21 can be pressed distally by the pressing portion 34. This allows the expandable body 21 to be extended distally and contracted radially.

[0088] 19(A), the distal ends of the wire rod portions 50 forming the expandable body 21 may be independent and not gathered together. The medical device 10 includes a first shaft 90 disposed inside the shaft portion 31 and protruding distally therefrom, a second shaft 91 disposed inside the first shaft 90 and protruding distally therefrom, and a pulling wire 80 capable of sliding through a lumen between the first shaft 90 and the second shaft 91. The distal ends of the pulling wire 80 are connected to the distal convex portions 57 of the wire rod portions 50. A guidewire lumen is formed inside the second shaft 91 along the axial direction, through which a guidewire 11 can be inserted. A distal end member 92 having an outer circumferential surface tapering toward the distal end is fixed to the outer circumferential surface of the distal end of the second shaft 91. The distal end member 92 functions as a dilator. The first shaft 90, the second shaft 91 and the tip member 92 may be formed integrally, or may be formed separately.

[0089] When using the medical device 10 of the sixth modification, as shown in Fig. 19(C), the expandable body 21 is stored in the outer tube 30, and the distal end member 92 is inserted into the through-hole Hh in the atrial septum HA with the distal end member 92 positioned distal to the outer tube 30. The through-hole Hh is widened by the distal end member 92, which serves as a dilator, and the outer tube 30 can be smoothly inserted into the through-hole Hh. Thereafter, by moving the outer tube 30 toward the proximal end, the expandable body 21 can be expanded radially by its own restoring force, as shown in Fig. 19(A).

[0090] 19(B), when the surgeon pulls the traction wire 80, which is the extension mechanism, in the proximal direction, the distal convex portion 57 is pulled toward the central axis of the expandable body 21, causing the expandable body 21 to contract radially. Thereafter, as shown in FIG. 19(C), by moving the outer tube 30 in the distal direction, the distal convex portion 57, which has been contracted radially by the traction wire 80, can be smoothly stored in the outer tube 30.

[0091] Furthermore, the structure of the expandable body 21 is not particularly limited and may be, for example, a mesh structure or a link structure. Furthermore, the expandable body 21 may have a structure other than an electrode (energy transmission element 22) provided in the recess 56. For example, the expandable body 21 may have a known cutting unit capable of cutting biological tissue disposed in the distal clamping unit 53 of the recess 56 (see, for example, Figures 28-29 of International Publication No. 2019 / 009254). This allows an incision to be formed at the edge of the through-hole Hh by moving the expandable body 21 toward the proximal end from a state in which the distal clamping unit 53 is expanded and positioned at the distal end of the through-hole Hh. The incision formed by the cutting unit makes it difficult for the biological tissue to elastically contract, so the through-hole Hh can be maintained in an expanded state.

[0092] The cutting unit can be configured, for example, by a cutter having a sharp blade surface, an electric scalpel, a laser cutter, or the like. The cutting unit may also be provided in the expandable body as a single component combined with the energy transmission element 22, etc. The cutting unit can also be disposed, for example, in the base-end clamping portion 52 of the recess 56. In such a configuration, for example, by moving the expandable body 21 toward the distal end, an incision can be formed at the edge of the through-hole Hh.

[0093] Furthermore, the expandable body 21 may not have an electrode (energy transmission element 22) in the recess 56. In this case, the medical device 10 having the expandable body 21 has the function of expanding the through-hole Hh formed in the atrial septum HA of the patient's heart H, and can extend the expandable body 21 toward the distal end or contract it radially using the extension mechanism, thereby reducing the load on the expandable body 21 and the outer tube 30 when the expandable body 21 is stored in the outer tube 30. [Explanation of symbols]

[0094] 10 Medical Devices 11 Guidewire 20 Long section 21 Extension 22 Energy Transfer Elements 23 Control section 30 outer cylinder 31 Shaft section 33 Operating shaft 34 Pressing section 35 Traction section 36 Pressing connection part 38 Pressing shaft 40 Housing 41 Dial 42 Conversion Mechanism 43 Repulsion mechanism 44 Limiting mechanism 45 Release mechanism 50 Wire section 51 Clamping part 52 Proximal side clamping part 53 Tip side clamping part 54 Gathering area 55 Proximal protrusion 56 Recess 57 Tip side protrusion 70 Inner tube 73 Slit 80 Towing Wire

Claims

1. an expandable body that is radially expandable and contractible and that is radially self-expandable to a deployed form by its own restoring force; a long shaft portion having a distal end portion to which the proximal end of the expansion body is fixed; an extension mechanism that passes through the inside of the shaft portion and is directly or indirectly connected to the expansion body; The expandable body has a recess that is recessed radially inward and defines a receiving space that can receive biological tissue when the expandable body is expanded, a distal-side convex portion that is disposed distally of the recess and protrudes radially outward, and a proximal-side convex portion that is disposed proximal to the recess and protrudes radially outward, The extension mechanism includes: an actuation shaft extending from the proximal end of the expandable body toward the distal end thereof along the central axis of the expandable body and movable in the axial direction of the shaft portion relative to the expandable body; a pressing portion that is connected to the actuation shaft on a base end side of the distal end portion of the expansion body and that is capable of pressing the distal end portion of the expansion body from the base end side to press the expansion body in a distal direction, A medical device in which the operating shaft is moved toward the tip relative to the expansion body in the expanded form, and the tip portion of the expansion body is pressed toward the tip with the pressing portion, causing an axial pulling force to act on the expansion body, causing the expansion body in the expanded form to extend toward the tip, and both the base-side convex portion and the tip-side convex portion to contract radially.

2. The medical device according to claim 1 , wherein the pressing portion is spaced proximally from a position where the pressing portion presses the distal end of the expandable body from the proximal end when the expandable body is in a fully contracted state.

3. A medical device as described in claim 1 or 2, wherein when the base-end convex portion of the expansion body is radially contracted, the pressing portion is farther toward the base end from the position where it presses the tip end of the expansion body from the base end side than the amount of base-end movement of the tip end of the expansion body that accompanies radial expansion of the base-end convex portion.

4. The extension mechanism includes: an inner tube connected to the distal end portion of the expandable body and extending toward a proximal end side beyond the distal end portion of the expandable body; the actuation shaft extends along a central axis of the expandable body from a proximal end of the expandable body to at least the interior of the inner tube; A medical device described in any one of claims 1 to 3, wherein the pressing portion is connected to the operating shaft on the base end side of the inner tube, and is able to abut against the base end of the inner tube from the base end side and press the tip end of the expandable body in the tip direction via the inner tube.

5. The extension mechanism includes: A medical device according to any one of claims 1 to 4, comprising a traction section connected to the actuation shaft further distally than the expansion body, contacting the distal end of the expansion body from the distal side and capable of pulling the distal end of the expansion body in a proximal direction relative to the proximal end of the expansion body.

6. A medical device as described in claim 5, wherein when the base-end convex portion of the expansion body is radially expanded, the traction portion is farther away from the tip end of the expansion body than the amount of distal movement of the tip end of the expansion body that accompanies radial contraction of the base-end convex portion.

7. an operating section connected to a base end of the shaft section; the operating unit has a repulsive mechanism that can accumulate a repulsive force by moving the actuation shaft toward the proximal end; a limiting mechanism for limiting axial movement of the actuation shaft; A medical device according to any one of claims 1 to 6, further comprising a release mechanism that releases the restriction imposed by the restriction mechanism and allows the actuation shaft to move toward the tip due to the accumulated repulsive force.

8. The medical device according to any one of claims 1 to 7, further comprising an electrode provided along the recess so as to face the receiving space.

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