catheter

Abstract

To improve operability of a catheter which has electrodes.SOLUTION: The catheter comprises: a hollow shaft; a tip electrode provided at the tip of the hollow shaft; a base end electrode provided at the base end of the hollow shaft and electrically connected with the tip electrode via the hollow shaft; and a connection part which is attachable to and detachable from the base end electrode and when it is attached to the base end electrode, electrically connects an external voltage output device with the base end electrode via a lead wire.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a catheter. [Background technology]

[0002] In recent years, minimally invasive catheter ablation has become a typical treatment for arrhythmia, etc. In catheter ablation, a medium to high-frequency electric current is applied from the tip of a catheter to the vicinity of the lesion to cauterize the lesion.

[0003] Patent Document 1 discloses an electrical current supply system for a cardiac ablation catheter. The catheter system described in Patent Document 1 has an accessory with a luer lock mechanism at the proximal portion of the catheter, and is provided with lead wires and connection terminals for electrically connecting to an output device via the accessory.

[0004] Patent Document 2 discloses an electrode catheter used for testing (diagnosis) and treating arrhythmia. This electrode catheter is equipped with an electrode provided at the tip of a catheter tube and a conductor that connects a connector provided on a handle provided at the proximal end of the catheter tube, and a part of the handle is separated and formed to be removable. When manufacturing the electrode catheter, the divided piece is removed and the base end of the conductor is soldered to the connector to establish an electrical connection. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Special Publication No. 8-508917 [Patent Document 2] JP 2014-180498 A Summary of the Invention [Problem to be solved by the invention]

[0006] In catheter treatments such as PCI (percutaneous coronary intervention), the surgeon is required to perform delicate operations to avoid blood vessel perforation and intima damage. However, when using the catheter described in Patent Document 1, it is difficult to operate because of the attachments and lead wires. In particular, when rotating the catheter, the lead wires may become entangled with the shaft, hindering operation. In the electrode catheter described in Patent Document 2, no consideration has been given to the decrease in operability caused by connecting the electrode catheter to an external device via a lead wire. Note that such problems are common to all catheters inserted into living lumens, such as the vascular system, lymphatic system, biliary system, urinary system, respiratory system, digestive system, secretory glands, and reproductive organs.

[0007] The present invention has been made to solve at least some of the above problems, and has an object to provide a technique for improving the operability of a catheter having an electrode. [Means for solving the problem]

[0008] The present invention has been made to solve at least part of the above-mentioned problems, and can be realized in the following forms.

[0009] (1) According to one aspect of the present invention, there is provided a catheter comprising: a hollow shaft, a tip electrode provided at a tip portion of the hollow shaft, a base electrode provided at a base end portion of the hollow shaft and electrically connected to the tip electrode via the hollow shaft, and a connection portion configured to be detachable from the base electrode and attached to the base electrode to electrically connect an external voltage output device to the base electrode via a lead wire.

[0010] According to this configuration, since the base electrode has a detachable connection part, when the surgeon inserts the catheter into the body and advances it through the blood vessel, the connection part can be detached from the base electrode. By detaching the connection part, it is possible to obtain the same operability as a catheter without a lead wire or an electrode. On the other hand, when the tip electrode of the catheter reaches the target position and conduction is required, such as for cauterization, the connection part can be attached to the base electrode and connected to an external voltage output device to establish conduction. In other words, by having a detachable connection part, it is possible to provide a catheter that is easy to operate when conduction is not required and can conduct electricity when necessary.

[0011] (2) In the catheter of the above aspect, the connection part may include a covering part that covers the base electrode when attached to the base electrode. In this way, the base electrode is covered by the connection part, so that the possibility of electric leakage due to the base electrode being exposed can be reduced.

[0012] (3) The catheter of the above embodiment may further include a gripping portion provided at the base end of the hollow shaft, the gripping portion having a distal gripping portion disposed at the distal end of the gripping portion, a proximal gripping portion disposed at the proximal end of the gripping portion, and an intermediate gripping portion disposed between the distal gripping portion and the proximal gripping portion, and the connecting portion may constitute the intermediate gripping portion. In this way, the connecting portion also functions as the intermediate gripping portion, so that the operability of the catheter can be improved even when the connecting portion is attached.

[0013] (4) The catheter of the above embodiment may further include an alternative part that is detachable from the base electrode, that is not attached to the base electrode, and that constitutes the intermediate grip part such that the base electrode and the voltage output device are not electrically connected when the alternative part is attached to the base electrode in place of the connection part. In this way, the base electrode is covered by the alternative part even when the connection part is not attached, thereby reducing the possibility of leakage current.

[0014] (5) In the catheter of the above embodiment, the covering portion includes a first cover portion having a first connection terminal connected to the lead wire, and a second cover portion connected to the first cover portion by a connecting portion having a hinge structure, and is configured to be openable and closable, and is attached to the base electrode in a closed state in which the base electrode is sandwiched between the first cover portion and the second cover portion, and is detachable from the base electrode by being opened, and the first connection terminal may be disposed in a position that contacts the base electrode when the connecting portion is attached to the base electrode. In this way, the connecting portion can be easily attached and detached by an opening and closing operation. Therefore, it is possible to quickly provide electrical continuity to the catheter. In addition, since the first connection terminal is disposed in a position that contacts the base electrode when the connecting portion is attached to the base electrode, electrical continuity can be easily ensured by attaching the connecting portion through a simple operation of closing the first cover portion and the second cover portion.

[0015] (6) In the catheter of the above aspect, at least one of the first cover part and the second cover part has an electrode groove into which the base electrode can be fitted, and the electrode groove is disposed at a position where the first connection terminal contacts the base electrode when the connection part is attached to the base electrode. In this way, the base electrode and the first connection terminal can be easily disposed at appropriate positions, and therefore, an electrical connection with an external voltage output device can be made with high accuracy.

[0016] (7) In the catheter of the above aspect, at least one of the first cover part and the second cover part may include a seal part surrounding an outer periphery of the electrode groove part. In this way, water infiltration into the base electrode can be suppressed, and therefore leakage of electricity can be suppressed.

[0017] (8) In the catheter of the above embodiment, the base grip portion may include a support portion provided on the distal end side of the base grip portion and fixedly supporting the base electrode, the support portion having a protrusion protruding in a direction from the central axis of the hollow shaft toward the outer periphery of the grip portion, and the intermediate grip portion may include a recess that fits into the support portion of the base grip portion. In this way, when an operator grips the intermediate grip portion and rotates the catheter, the rotational force applied to the intermediate grip portion is transmitted to the base electrode via the support portion, thereby suppressing free rotation of the intermediate grip portion and improving the torque transmission of the catheter.

[0018] (9) In the catheter of the above aspect, the tip gripping portion may have a tapered portion that narrows toward the tip, and the tapered portion may have a helical groove formed on the surface. In this way, the tapered portion is made flexible, and kinking of the hollow shaft can be suppressed.

[0019] (10) In the catheter of the above embodiment, when the intermediate gripping portion is constituted by the connecting portion, the distal gripping portion can support the lead wire along a surface of the distal gripping portion, and may have a lead wire recess on its surface into which the lead wire can be fitted. In this way, the lead wire can be aligned along the surface of the distal gripping portion, thereby preventing deterioration of operability due to the lead wire.

[0020] (11) In the catheter of the above embodiment, the lead wire may include a second connection terminal disposed at its tip and electrically connectable to the voltage output device, and the catheter may include a terminal support part capable of supporting the second connection terminal, on the tip grip part. In this way, when the electrical connection between the second connection terminal and the voltage output device is cut off and the catheter is operated with the connection part attached, the second connection terminal can be fixed to the tip grip part by the terminal support part. Therefore, it is possible to suppress a decrease in operability caused by the lead wire getting tangled in the catheter due to the second connection terminal of the lead wire moving freely.

[0021] The present invention can be realized in various forms, for example, in the form of a catheter, or a catheter system including a catheter and other devices such as a sensor, a delivery guidewire, or a plasma guidewire. [Brief description of the drawings]

[0022] [Figure 1] 1 is a schematic diagram of an overall configuration of a plasma guidewire system according to a first embodiment. [Diagram 2] FIG. 1 is an explanatory diagram showing a schematic configuration of a plasma catheter according to a first embodiment. [Diagram 3] 1 is an explanatory diagram of the configuration of a gripping portion of a plasma catheter. FIG. [Figure 4] FIG. 2 is an explanatory diagram illustrating a schematic configuration of a hollow shaft and a base electrode. [Diagram 5] 4 is an explanatory diagram illustrating a schematic configuration of a support part that fixes and supports a base electrode. FIG. [Figure 6] Schematic explanation of the structure of the connection part [Figure 7] 4 is an explanatory diagram illustrating a schematic configuration of the inner surfaces of a first cover portion and a second cover portion. FIG. [Figure 8] FIG. 4 is an explanatory diagram illustrating a tip surface of a connection portion. [Figure 9] FIG. 4 is an explanatory diagram illustrating a base end surface of a connection portion. [Figure 10] 4 is an explanatory diagram showing a state in which a first connection terminal contacts a base electrode. FIG. [Figure 11] 10 is an explanatory diagram showing a schematic appearance of a tip gripping portion of a plasma catheter according to a second embodiment. FIG. [Figure 12] 13 is an explanatory diagram showing a schematic appearance of a terminal support part of a plasma catheter according to a third embodiment. FIG. [Figure 13] FIG. 13 is an explanatory diagram showing the schematic configuration of a plasma catheter according to a fourth embodiment. [Figure 14] 4 is an explanatory diagram illustrating a schematic configuration of a support part that fixes and supports a base electrode. FIG. [Figure 15] FIG. 4 is an explanatory diagram illustrating a base end surface of a connection portion. [Figure 16] FIG. 11 is an explanatory diagram illustrating a schematic external configuration of a plasma catheter according to a fifth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] First Embodiment FIG. 1 is a schematic diagram of the overall configuration of a plasma guidewire system. The plasma guidewire system is mainly used when treating CTO (Chronic Total Occlusion) by a antegrade approach. The plasma guidewire system may be used to treat mild to moderate stenosis, significant stenosis, arrhythmia, and the like, in addition to CTO treatment. The plasma guidewire system 1 is composed of a plasma catheter 100, a plasma guidewire 400, and an RF generator 500. FIG. 1 shows a schematic side view of the plasma catheter 100. For convenience of explanation, FIG. 1 includes a portion in which the relative ratio of the size of each component is depicted differently from the actual one. Also, it includes a portion in which some of the components are depicted in an exaggerated manner. In FIG. 1, the left side is called the "tip side" of each component, and the right side is called the "base side" of each component. Also, for each component, the end portion located on the tip side is called the "tip" and the end portion located on the base side is called the "base". In addition, the tip and the part located near the tip are called the "tip portion," and the base and the part located near the base are called the "base end portion." The tip side is inserted into the living body, and the base side is operated by a surgeon such as a doctor. These points are the same in Figure 1 and subsequent figures.

[0024] The plasma catheter 100 includes a hollow shaft 10, a tip electrode 20 provided at the tip of the hollow shaft 10, a base electrode (described later) provided at the base end of the hollow shaft 10, a grip 50 provided at the base end of the hollow shaft 10, and a connector 70. The plasma guidewire 400 includes a tip tip 403 at its tip. The tip tip 403 is formed of a metal material having electrical conductivity, and may be formed of, for example, chromium molybdenum steel, nickel chromium molybdenum steel, stainless steel such as SUS304, nickel titanium alloy, or the like.

[0025] The RF generator 500 outputs high-frequency power between a terminal 501 and a terminal 502. The terminal 501 is connected to the plasma guidewire 400 via a cable 503 and a cable connector 504. The terminal 502 is connected to the plasma catheter 100 via a cable 505 and a cable connector 506.

[0026] As shown in the figure, in the plasma guidewire system 1, the plasma guidewire 400 is inserted into the plasma catheter 100 and is used in such a manner that its tip portion protrudes from the tip of the plasma catheter 100.

[0027] When the plasma catheter 100 is delivered to the CTO and the tip of the plasma guidewire 400 protrudes from the tip of the plasma catheter 100, high-frequency power is output from the RF generator 500 between the terminals 501 and 502. Due to the voltage difference between the tip electrode 20 of the plasma catheter 100 and the tip tip 403 of the plasma guidewire 400, a streamer corona discharge is generated at the tip tip 403. This streamer corona discharge can ablate the CTO.

[0028] Fig. 2 is an explanatory diagram showing a schematic configuration of the plasma catheter 100 of the first embodiment. As described above, the plasma catheter 100 has a gripping portion 50 at the base end of the hollow shaft 10. As shown in Fig. 2(A), the gripping portion 50 has a distal gripping portion 52 arranged at the distal end of the gripping portion 50, a proximal gripping portion 54 arranged at the proximal end of the gripping portion 50, and an intermediate gripping portion 56 arranged between the distal gripping portion 52 and the proximal gripping portion 54. The gripping portion 50 is formed of an insulating resin.

[0029] The intermediate gripping portion 56 may be constituted by a connection portion 40 that is electrically connectable to the RF generator 500 via a lead wire 42. As shown in Fig. 2(B), a base end electrode 30 is provided at the base end of the hollow shaft 10, which is electrically connected to the tip electrode 20 (Fig. 1) via the hollow shaft 10. The connection portion 40 is formed so as to be detachable from the base end electrode 30. Fig. 2(A) shows a state in which the connection portion 40 is attached to the base end electrode 30, and Fig. 2(B) shows a state in which the connection portion 40 is detached from the base end electrode 30.

[0030] The connection unit 40 includes a covering portion 44 that covers the proximal electrode 30 when attached to the proximal electrode 30, and a lead wire 42 (FIG. 2(A)). The lead wire 42 includes a second connection terminal 422 at its tip that can be electrically connected to the RF generator 500. In this embodiment, the second connection terminal 422 is connected to the cable connector 506, and is electrically connected to the RF generator 500 via the cable connector 506 (FIG. 1), the cable 505, and the terminal 502. The covering portion 44 has a first connection terminal (described in detail later) therein that connects to the proximal electrode 30, and when the connection unit 40 is attached to the proximal electrode 30 and the second connection terminal 422 is connected to the RF generator 500 via the cable connector 506, the cable 505, and the terminal 502, the proximal electrode 30 and the RF generator 500 are electrically connected.

[0031] The tip gripping portion 52 has a tapered portion 522 that narrows toward its tip. The tapered portion 522 has a spiral groove portion 524 formed in a spiral groove shape on the surface. Since the tip gripping portion 52 has the tapered portion 522 with the spiral groove portion 524 formed therein, hollow The sudden change in rigidity between the tip grip portion 52 and the shaft 10 is mitigated. hollowA gradual change in stiffness is achieved between the hollow shaft 10 and the tip gripping portion 52. This makes it possible to suppress kinking of the hollow shaft 10. Furthermore, when the intermediate gripping portion 56 is formed by the connection portion 40, the tip gripping portion 52 can support the lead wire 42 along the surface of the tip gripping portion 52, and has a lead wire recess 526 on its surface into which the lead wire can be fitted. Because the tip gripping portion 52 has the lead wire recess 526, the lead wire 42 can be aligned along the surface of the tip gripping portion, making it possible to suppress a decrease in operability due to the lead wire 42.

[0032] FIG. 3 is an explanatory diagram of the configuration of the gripping section 50 in the plasma catheter 100. As described above, in the plasma catheter 100 of this embodiment, the intermediate gripping section 56 can be configured by the connection section 40. The intermediate gripping section 56 can also be configured by the replacement section 60. That is, the plasma catheter 100 is configured so that the connection section 40 and the replacement section 60 can be replaced (FIG. 3(A)). The replacement section 60 is detachable from the proximal electrode 30, like the connection section 40, and is attached to the proximal electrode 30 in place of the connection section 40 when the connection section 40 is not attached to the proximal electrode 30, forming the intermediate gripping section 56 (FIG. 3(B)). The replacement section 60 does not include the lead wire 42, nor does it include a connection terminal for connecting to the proximal electrode 30. Therefore, when the replacement section 60 is attached to the proximal electrode 30, the proximal electrode 30 and the RF generator 500 are not electrically connected. When the replacement portion 60 is attached to the base electrode 30 to form the intermediate grip portion 56, it is possible to suppress a decrease in operability caused by the lead wire becoming entangled in the grip portion 50 or the hollow shaft 10. In addition, since the replacement portion 60 does not include the lead wire 42 and does not include a connection terminal for connecting to the base electrode 30, it is lighter than the connection portion 40 and easier to operate than when the connection portion 40 is attached. Therefore, when the replacement portion 60 is attached, the plasma catheter 100 can exhibit the same operability as a general catheter that does not have a current-carrying configuration.

[0033] Fig. 4 is an explanatory diagram showing a schematic configuration of the hollow shaft 10 and the base electrode 30. Fig. 4(A) shows a schematic appearance of the hollow shaft 10 and the base electrode 30. Fig. 4(A) shows a state in which the distal grip portion 52 is divided along the axis, exposing the hollow shaft 10 and the base electrode 30. As shown in the figure, the base electrode 30 is provided at the base end of the hollow shaft 10.

[0034] Fig. 4(B) is an explanatory diagram that shows a schematic cross-sectional configuration of the hollow shaft 10, showing the AA cross section in Fig. 4(A). The hollow shaft 10 has a hollow outer shaft 12 and a hollow inner shaft 14 disposed within the outer lumen of the outer shaft 12. The outer shaft 12 and the inner shaft 14 are long and have a substantially circular cross section.

[0035] A hollow rope coil 16 formed by winding a wire is embedded inside the outer shaft 12. The wire constituting the rope coil 16 is made of a metal material having electrical conductivity, and may be made of, for example, stainless steel such as SUS304, a nickel-titanium alloy, or an alloy containing gold, platinum, or tungsten, which is an X-ray opaque material. The rope coil 16 is electrically connected to the distal electrode 20 and the proximal electrode 30. The outer surface of the outer shaft 12 may be coated with a water-repellent resin or a hydrophobic resin.

[0036] A braid 18, which is a reinforcing member formed by braiding wires, is embedded inside the inner shaft 14. The wires constituting the braid 18 are made of a conductive metal material, similar to the rope coil 16, and may be made of, for example, stainless steel such as SUS304, a nickel-titanium alloy, or an alloy containing gold, platinum, or tungsten, which is an X-ray opaque material. The rope coil 16 and the braid 18 may be made of a known conductive metal material other than those mentioned above.

[0037] The outer shaft 12 and the inner shaft 14 are formed of an insulating resin, and may be formed, for example, of polyolefins such as polyethylene, polypropylene, ethylene-propylene copolymer, polyesters such as polyethylene terephthalate, polyvinyl chloride, ethylene-vinyl acetate copolymer, cross-linked ethylene-vinyl acetate copolymer, thermoplastic resins such as polyurethane, polyamide elastomers, polyolefin elastomers, polyurethane elastomers, silicone rubber, latex rubber, etc. The outer shaft 12 and the inner shaft 14 may be formed of known materials other than those mentioned above.

[0038] FIG. 4(C) is an explanatory diagram showing a schematic cross-sectional configuration of the base electrode 30, showing the BB cross section in FIG. 4(A). The base electrode 30 is hollow tubular, and its cross section is approximately circular. Since the base electrode 30 is hollow tubular, the plasma guide wire 400 can be passed through the inside or a drug solution can be injected through the connector 70. The base electrode 30 is formed of a metal material having electrical conductivity, and can be formed of, for example, stainless steel such as SUS304, nickel-titanium alloy, aluminum, copper, gold, platinum, tungsten, or an alloy containing at least one of these metals. The resin layer of a part of the outer shaft 12 at the base end of the hollow shaft 10 is peeled off, and the rope coil 16 is inserted into the lumen of the base electrode 30 in a state where it is exposed, and the base electrode 30 and the rope coil 16 are connected by welding. The tip electrode 20 provided at the tip of the hollow shaft 10 is also formed of a metal material having electrical conductivity, like the base electrode 30, and is connected to the rope coil 16. Therefore, the distal electrode 20 and the proximal electrode 30 are electrically connected via the rope coil 16. A PTFE (polytetrafluoroethylene) layer may be formed on the inner surface of the proximal electrode 30. By forming the PTFE layer, it is possible to improve biocompatibility and slipperiness. A PE (polyethylene) layer or a PA (polyamide) layer may be formed instead of the PTFE layer. The PE layer or PA layer can also improve biocompatibility and slipperiness. By forming the distal electrode 20 from an alloy containing gold, platinum, or tungsten, which is an X-ray opaque material, the distal electrode 20 can function as an X-ray opaque marker in the body cavity.

[0039] FIG. 5 is an explanatory diagram showing a schematic configuration of a support section 542 that fixes and supports the base electrode 30. FIG. 5(A) shows a side view, and FIG. 5(B) shows a view seen from the tip grip section 52 side. The base grip section 54 includes a support section 542 that fixes and supports the base electrode 30 on the tip side of the base grip section 54. The support section 542 has a protrusion 544 that protrudes in a direction from the central axis of the hollow shaft 10 (which coincides with the central axis of the base electrode 30) toward the outer periphery of the intermediate grip section 56. The tip grip section 52 also includes a tip side support section 528 that fixes and supports the base electrode 30 on the base end side. The tip side support section 528 is cylindrical and has a central axis that coincides with the base electrode 30. In this embodiment, the tip side support section 528 does not include a protrusion such as the protrusion 544, but in other embodiments, the tip side support section 528 may also include a protrusion. Also, the support portion 542 may not include the protrusion 544, and the tip side support portion 528 may include the protrusion.

[0040] FIG. 6 is an explanatory diagram (perspective view) that shows a schematic configuration of the connection part 40. FIG. 7 is an explanatory diagram that shows a schematic configuration of the inner surface of the first cover part 441 and the second cover part 442. FIG. 8 is an explanatory diagram that shows a schematic distal end surface 44a of the connection part 40, and FIG. 9 is an explanatory diagram that shows a schematic proximal end surface 44b of the connection part 40. When the connection part 40 is attached to the proximal electrode 30, the distal end surface 44a is disposed on the distal end side, and the proximal end surface 44b is disposed on the proximal end side. FIGS. 6, 8, and 9 (A) show the connection part 40 in a closed state, and FIGS. 6, 8, and 9 (B) show the connection part 40 in an open state. As described above, the connection part 40 includes the lead wire 42 and the covering part 44. The covering part 44 includes a first cover part 441 and a second cover part 442. The first cover part 441 and the second cover part 442 are connected by a connecting part 444 having a hinge structure, and can be moved between a closed state (FIG. 6(A)) and an open state (FIG. 6(B)). As shown in FIG. 7, the connecting part 444 includes a shaft 444a, a rotation support part 444b (FIG. 7(A)) having a hole through which the shaft is inserted, and a rotation support part 444c (FIG. 7(B)). The rotation support part 444b is formed integrally with the first cover part 441, and the rotation support part 444c is formed integrally with the second cover part 442. The first cover part 441 and the second cover part 442 are connected so as to be openable and closable by inserting the shaft 444a into the holes of the rotation support part 444b and the rotation support part 444c. The connection portion 40 is attached to the base electrode 30 in a closed state (Figure 6(A)) in which the base electrode 30 is clamped between the first cover portion 441 and the second cover portion 442, and can be detached from the base electrode 30 by placing it in an open state (Figure 6(B)).

[0041] As shown in Fig. 7(A), the first cover portion 441 includes an outer shell 441j and an inner shell 441k. Similarly, as shown in Fig. 7(B), the second cover portion 442 includes an outer shell 442j and an inner shell 442k. The outer shells 441j and 442j may be made of a material having a relatively high rigidity, such as polyamide resin, polyethylene resin, ABS (acrylonitrile butadiene styrene) resin, etc. The inner shells 441k and 442k may be made of a material having a relatively high flexibility, such as silicone resin, elastomer, rubber, etc.

[0042] As shown in Fig. 7, the second cover part 442 has a button part 442h and a hook part 442i connected to the button part 442h, and the first cover part 441 has a hole part 441i to which the hook part 442i can be hooked. As shown in Fig. 6(A), when the first cover part 441 and the second cover part 442 are closed, the hook part 442i and the hole part 441i are hooked to maintain the closed state. In addition, when the button part 442h is pressed in the closed state of the first cover part 441 and the second cover part 442, the hook part 442i connected to the button part 442h comes out of the hole part 441i, the hook part 442i and the hole part 441i are released from the hook part 442i and the hole part 441i are released, and the first cover part 441 and the second cover part 442 are opened. In this way, the surgeon can attach the connection part 40 to the base electrode 30 by closing the first cover part 441 and the second cover part 442, and can detach the connection part 40 from the base electrode 30 by pressing the button part 442h. That is, the connection part 40 of the present embodiment can provide the surgeon with ease of attachment and detachment.

[0043] 8, the lead wire 42 is provided so as to penetrate the first distal end surface 441a of the first cover part 441. The first connection terminal 421 arranged at one end of the lead wire 42 is provided so as to be exposed to the inner surface 441c of the first cover part 441 (FIG. 7(A)). The first connection terminal 421 is arranged at a position where it comes into contact with the base electrode 30 when the connection part 40 is attached to the base electrode 30.

[0044] The first cover part 441 has an electrode groove 441d in an inner shell 441k part of the inner surface 441c, into which the base electrode 30 can be fitted. Similarly, the second cover part 442 has an electrode groove 442d in an inner shell 442k part of the inner surface 442c, into which the base electrode 30 can be fitted. When the first cover part 441 and the second cover part 442 are in a closed state, the electrode groove 441d and the electrode groove 442d form a through hole having a substantially circular cross section (FIGS. 8(A) and 9(A)). When the connection part 40 is attached to the base electrode 30, the electrode groove 441d and the electrode groove 442d cover the outer peripheral surface of the base electrode 30. As shown in FIG. 7(A), the first connection terminal 421 is arranged in the electrode groove portion 441d. Therefore, when the base electrode 30 is arranged in the electrode groove portion 441d, the base electrode 30 and the first connection terminal 421 are easily arranged in appropriate positions, thereby enabling accurate electrical connection with the RF generator 500.

[0045] The first cover part 441 is provided, at an inner shell 441k part of the inner surface 441c, with a tip side recess 441e into which the tip side support part 528 of the tip grip part 52 can be fitted, and a base side recess 441f into which the support part 542 of the base end grip part 54 can be fitted. Similarly, the second cover part 442 is provided, at an inner shell 442k part of the inner surface 442c, with a tip side recess 442e into which the tip side support part 528 of the tip grip part 52 can be fitted, and a base side recess 442f into which the support part 542 of the base end grip part 54 can be fitted. When the first cover part 441 and the second cover part 442 are in the closed state, the base side recess 441f and the base side recess 442f form a hole whose shape of the inner cavity is approximately the same as that of the support part 542 of the base end grip part 54 (FIG. 9(A)). As described above, the support portion 542 of the base end grip portion 54 has the protrusion portion 544 protruding from the central axis of the hollow shaft 10 toward the outer periphery of the grip portion 50, and the connection portion 40 has the base end recess 441f and the base end recess 442f into which the support portion 542 fits. Therefore, when the connection portion 40 is attached to the base end electrode 30 to form the intermediate grip portion 56, when the surgeon grasps the intermediate grip portion 56 and rotates the catheter, the rotational force applied to the intermediate grip portion 56 is transmitted to the base end electrode 30 via the support portion 542, so that the idling of the intermediate grip portion 56 is suppressed, and the torque transmission of the plasma catheter 100 can be improved. The base end recess 441f and the base end recess 442f in this embodiment are also simply referred to as "recesses".

[0046] As shown in FIG. 7B, a protruding seal portion 442g surrounding the outer periphery of the electrode groove portion 442d is formed in the inner shell 442k portion of the inner surface 442c of the second cover portion 442. As shown in FIG. 7A, a protruding seal portion 441g straddling the distal end recess 441e and a protruding seal portion 441g straddling the proximal end recess 441f are formed in the inner shell 442k portion of the inner surface 441c of the first cover portion 441, corresponding to the seal portion 442g of the second cover portion 442. In FIG. 7, the protruding seal portions 441g and 442g are illustrated with oblique line hatching. When the first cover portion 441 and the second cover portion 442 are closed and attached to the proximal electrode 30, the periphery of the proximal electrode 30 can be surrounded by the seal portions 441g and 442g. Therefore, when the plasma catheter 100 is used, the base electrode 30 can be prevented from being inundated with water, and leakage current can be prevented. The connection part 40 of this embodiment can provide waterproofing against wetness that is expected in clinical situations, such as when the hands of a surgeon such as a doctor are wet with physiological saline. Therefore, even if the base electrode 30 gets wet when the connection part 40 is attached or detached during surgery, the base electrode 30 is surrounded by the seal parts 442g, 441g by attaching the connection part 40, and therefore can be kept insulated from the outer shells 441j, 442j of the connection part 40. Therefore, safety against leakage current during discharge can be provided.

[0047] Although the replacement part 60 does not include the lead wire 42 and the first connection terminal 421, it has a configuration substantially similar to that of the connection part 40, and can be attached to and detached from the proximal electrode 30 by opening and closing the first cover part and the second cover part, and a seal part surrounding the proximal electrode 30 is formed on the inner surface of the first cover part and the second cover part. Therefore, even when the replacement part 60 is attached to the proximal electrode 30, the proximal electrode 30 is covered and has the same waterproofing as when the connection part 40 is attached. Furthermore, the replacement part 60 has the same torque transmission ability as the connection part 40.

[0048] FIG. 10 is an explanatory diagram showing a state where the first connection terminal 421 contacts the base electrode 30. In FIG. 10, in order to clearly show the state of the first connection terminal 421, illustration of components other than the first connection terminal 421 of the connection part 40 is omitted. The first connection terminal 421 has two contact parts 421a that contact the base electrode 30. When the base electrode 30 is sandwiched between the first cover part 441 and the second cover part 442, the first connection terminal 421 and the base electrode 30 contact each other at the two 421a (FIG. 10(A)). At this time, the hook part 442i and the hole part 441i are not yet engaged. By pressing the first cover part 441 and the second cover part 442 from the outside toward the inside of the first cover part 441 and the second cover part 442, the hook part 442i and the hole part 441i are engaged, and the closed state of the covering part 44 is maintained (locked). In this way, when the first cover part 441 and the second cover part 442 are pressed together, the first connection terminal 421 is crushed, and the two contact parts 421a slide closer to each other on the surface of the base electrode 30. As a result, even if a foreign object is attached to the base electrode 30, it can be peeled off by the first connection terminal 421, and good electrical conductivity can be obtained.

[0049] In the plasma guidewire system 1 of this embodiment, for example, the CTO can be opened as follows. First, the operator uses the plasma catheter 100 with the replacement part 60 attached to the proximal electrode 30 and the intermediate grip part 56 configured in the plasma catheter 100. First, the proximal end of the delivery guidewire (not shown) is inserted from the opening 104a (FIG. 1) at the tip of the plasma catheter 100, and protrudes from the proximal end of the inner lumen through the inner lumen of the inner shaft 14 (FIG. 4). Then, the operator grasps the grip part 50 including the replacement part 60 to operate the plasma catheter 100, and carries the plasma catheter 100 along the delivery guidewire to the CTO formed in the coronary artery. After that, the operator positions the tip of the plasma catheter 100 at an optimal position for penetration into the true lumen by, for example, injecting a contrast agent from the inner lumen of the inner shaft 14 through the connector 70 (FIG. 1) of the plasma catheter 100 and taking an X-ray. After placing the plasma catheter 100 at the optimal position, the surgeon removes the delivery guidewire and inserts a new plasma guidewire 400 (FIG. 1) into the inner lumen of the inner shaft 14. The surgeon carries the distal end of the plasma guidewire 400 to the distal end of the plasma catheter 100 and protrudes the distal end of the plasma guidewire 400 from the opening 104a. After that, the surgeon removes the replacement part 60 from the proximal electrode 30 in the plasma catheter 100 and attaches the connection part 40 to the proximal electrode 30 instead. At this time, the lead wire 42 of the connection part 40 is connected to the cable connector 506, and the connection part 40 is attached to the proximal electrode 30, thereby establishing electrical continuity between the plasma catheter 100 and the RF generator 500. The surgeon operates the RF generator 500 to generate a streamer corona discharge at the distal tip 403 of the plasma guidewire 400 and ablate the CTO.

[0050] For example, after removing the delivery guide wire, an imaging sensor may be inserted into the inner lumen of the inner shaft 14, and the position of the plasma catheter 100 may be adjusted using an image from the imaging sensor instead of X-ray photography.

[0051] As described above, the plasma catheter 100 of this embodiment has a connection part 40 that is detachably attached to the base electrode 30 and electrically connects the RF generator 500 and the base electrode 30 via the lead wire 42 by being attached to the base electrode 30. Therefore, when electrical continuity is not required, the connection part 40 can be removed, and when electrical continuity is required, the connection part 40 can be attached to use the plasma catheter 100. Therefore, as described above, when the operator inserts the plasma catheter 100 into the body and advances it through the blood vessel, the connection part 40 can be removed from the base electrode 30, and the lead wire 42 and the first connection terminal 421 can be removed, thereby obtaining good operability similar to that of a catheter without a lead wire. On the other hand, when electrical continuity is required, such as when the distal electrode 20 of the plasma catheter 100 reaches the target position and cauterization is performed, the connection part 40 can be attached to the base electrode 30 and connected to the RF generator 500 to establish electrical continuity. That is, by having a detachable connection portion 40, it is possible to provide a catheter which has good operability when electricity is not required and which can be energized when necessary.

[0052] The plasma catheter 100 is also configured so that the connection part 40 and the replacement part 60 can be replaced (FIG. 3(A)). The replacement part 60 does not include a lead wire 42, and therefore when the replacement part 60 is attached to the proximal electrode 30 to form the intermediate grip part 56, it is possible to suppress a decrease in operability due to the lead wire becoming entangled in the grip part 50 or the hollow shaft 10. Furthermore, the replacement part 60 includes a seal part similar to that of the connection part 40, and therefore even when the replacement part 60 is attached, it is possible to ensure the same waterproofing as when the connection part 40 is attached.

[0053] Furthermore, in the plasma catheter 100, the connection part 40 can be easily attached to and detached from the base electrode 30 by opening and closing the first cover part 441 and the second cover part 442, so that the connection part 40 can be quickly attached to the base electrode 30 and electrical continuity can be quickly established in the catheter.

[0054] <Second embodiment> 11 is an explanatory diagram showing a schematic appearance of the tip gripping section 52A of the plasma catheter 100A of the second embodiment. The plasma catheter 100A of this embodiment differs from the plasma catheter 100 of the first embodiment in that it is provided with a terminal support section 528A capable of supporting the second connection terminal 422 of the lead wire 42. In the embodiment described below, the same components as those of the plasma catheter 100 of the first embodiment are given the same reference numerals, and the preceding description is to be referred to.

[0055] As shown in FIG. 11(A), the terminal support part 528A of this embodiment is formed in a groove shape on the surface of the portion of the tapered part 522A of the distal end grip part 52A where the spiral groove part 524 is not formed. FIG. 11(B) shows the CC section in FIG. 11(A) and shows a cross section of the terminal support part 528A. As shown in the figure, the terminal support part 528A has a narrower width at the cutout part on the surface of the tapered part 522A, so that the distal end part of the second connection terminal 422 does not come off from the surface side of the tapered part 522A. FIG. 11(C) shows the state in which the connection part 40 is attached to the plasma catheter 100A and the second connection terminal 422 of the lead wire 42 is supported by the terminal support part 528A. The surgeon can cause the second connection terminal 422 to be supported by the tip side support portion 528 by inserting the tip of the second connection terminal 422 into the terminal support portion 528A from the tip side of the terminal support portion 528A.

[0056] According to the plasma catheter 100A of this embodiment, when the second connection terminal 422 is removed from the cable connector 506 (FIG. 1) with the connection part 40 attached to the base electrode 30, and the electrical connection between the second connection terminal 422 and the voltage output device (RF generator 500) is cut off to operate the plasma catheter 100A, the second connection terminal 422 can be fixed to the distal grip part 52A by the terminal support part 528A. Therefore, it is possible to suppress a decrease in operability due to the lead wire getting tangled in the catheter when the second connection terminal 422 of the lead wire 42 is not fixed and moves freely.

[0057] <Third embodiment> FIG. 12 is an explanatory diagram that shows a schematic appearance of the terminal support part 528B of the plasma catheter 100B of the third embodiment. The terminal support part 528B of this embodiment is configured separately from the tip grip part 52, unlike the terminal support part 528A of the second embodiment. That is, the shape of the tip grip part 52 is the same as that of the first embodiment. As shown in FIG. 12(A), the terminal support part 528B of this embodiment is attached to the tip side of the tapered part 522. FIG. 12(B) is a view of the terminal support part 528B as seen from the tip side. As shown in the figure, the terminal support part 528B includes an open ring-shaped first member 528l, an open ring-shaped second member 528c similar to the first member 528l, and a rod-shaped third member 528s that connects the first member 528l and the second member 528c. The surgeon can attach the terminal support part 528B to the tip grip part 52 by fitting the second member 528c to the tapered part 522, and can support the second connection terminal 422 of the lead wire 42 on the terminal support part 528B by fitting the second connection terminal 422 to the first member 528l. Even in this way, it is possible to suppress the deterioration of operability due to the lead wire, as in the second embodiment.

[0058] <Fourth embodiment> Fig. 13 is an explanatory diagram showing the general configuration of a plasma catheter 100C of the fourth embodiment, Fig. 14 is an explanatory diagram showing the configuration of a support part 542C that fixes and supports a base-end electrode 30, and Fig. 15 is an explanatory diagram showing the general configuration of a base-end surface 44bC of a connection part 40C. Figs. 13, 14, and 15 correspond to Figs. 2, 5, and 9 of the first embodiment, respectively. The plasma catheter 100C of this embodiment differs from the plasma catheter 100 of the first embodiment in the shape of a tapered part 522C of a distal grip part 52C, the configuration of a connection part 40C, and the shape of a support part 542C of a base-end grip part 54.

[0059] As shown in FIG. 13, the tapered portion 522C does not include the spiral groove portion 524. 14, the support portion 542C is substantially hexagonal prism-shaped, and as shown in FIG. 15, the cross-sectional shape of the hole formed by the base-end recess 441fC and the base-end recess 442fC of the connection portion 40C is substantially hexagonal prism-shaped and substantially coincides with that of the support portion 542C. Although the support portion 542C does not have a protrusion 544 protruding from the central axis of the hollow shaft 10 toward the outer periphery of the grip portion 50, the support portion 542C is substantially hexagonal prism-shaped and is fitted into the base-end recess 441fC and the base-end recess 442fC of the connection portion 40C. When the operator holds the connection portion 40C and rotates the plasma catheter 100C, the rotational force applied to the connection portion 40C is transmitted to the base electrode 30 via the support portion 542C. This suppresses idling of the connection portion 40C, and provides a catheter with good torque transmission.

[0060] <Fifth embodiment> FIG. 16 is an explanatory diagram showing a schematic external configuration of a plasma catheter 100D of the fifth embodiment. The plasma catheter 100D does not have a lead wire 42, but has a connection part 40D into which the first connection terminal 421 of the lead wire 42 is inserted. The connection part 40D has an attachment part into which the first connection terminal 421 is inserted and which is attached to the base electrode 30 and establishes conduction with the RF generator 500. That is, the connection part 40D is attached to the base electrode 30 by inserting the first connection terminal 421, is detached from the base electrode 30 by removing the first connection terminal 421, and is attached to and detached from the base electrode 30 in response to the insertion and removal of the first connection terminal 421. The connection part 40D does not cover the base electrode 30. Even in this way, when conduction is required, conduction is ensured by connecting the lead wire 42, and when conduction is not required, the lead wire 42 can be removed to improve operability.

[0061] <Modifications of this embodiment> The present invention is not limited to the above-described embodiment, and can be embodied in various forms without departing from the spirit and scope of the invention. For example, the following modifications are also possible.

[0062] In the above embodiment, the plasma catheter 100 is exemplified as a catheter, and the plasma guidewire system 1 is exemplified, but the catheter is not limited to a plasma catheter. It is sufficient that the catheter is configured as a catheter having a tip electrode and a base electrode, and it may be configured as, for example, a catheter for inspection or diagnosis. For example, it may be configured with an image sensor.

[0063] In the above embodiment, the connection portion 40 covers the proximal electrode 30, but the connection portion 40 does not have to cover the proximal electrode 30. The proximal electrode 30 may be covered by a component separate from the connection portion 40.

[0064] In the above embodiment, the plasma catheter 100 is illustrated as having the alternative portion 60, but the alternative portion 60 may not be provided.

[0065] In the above embodiment, a hollow tubular proximal electrode 30 is exemplified, but the shape of the proximal electrode 30 is not limited to the above embodiment, and the proximal electrode 30 can be formed into various shapes such as a rod shape, a ring shape, a tip shape, etc. As in the above embodiment, forming the proximal electrode 30 into a hollow tubular shape and connecting it to the hollow shaft 10 is preferable because it allows a guide wire to be inserted into the inner cavity of the proximal electrode 30 or a medicinal solution to be injected through the inner cavity of the proximal electrode 30.

[0066] In the above embodiment, the proximal electrode 30 is electrically connected to the distal electrode 20 via the rope coil 16 of the hollow shaft 10, but the electrical connection between the proximal electrode 30 and the distal electrode 20 is not limited to the above embodiment. For example, the connection may be via the blade 18 of the hollow shaft 10, or the hollow shaft 10 may be provided with a conductor for connecting the proximal electrodes 30 and 20.

[0067] In the above embodiment, an example was shown in which the connection portion 40 constituted the intermediate grip portion 56 . However, the connection portion 40 does not have to constitute the intermediate grip portion 56 .

[0068] Although the present aspect has been described above based on the embodiment and modified examples, the above-mentioned embodiment of the aspect is intended to facilitate understanding of the present aspect and does not limit the present aspect. The present aspect may be modified or improved without departing from the spirit and scope of the claims, and equivalents are included in the present aspect. Furthermore, if a technical feature is not described as essential in this specification, it may be deleted as appropriate. [Explanation of symbols]

[0069] 1. Plasma guidewire system 10…Hollow shaft 12…Outer shaft 14…Inner shaft 16…Rope coil 18…Blade 20…Tip electrode 30...Proximal electrode 40, 40C, 40D…Connections 42…Lead wire 44…Covering part 44a…Tip surface 44b, 44bC...Proximal surface 50...Gripping part 52, 52A, 52C...Tip grip part 54...Proximal grip part 56…Intermediate gripping part 60…Alternative part 70…Connector 100, 100A, 100B, 100C, 100D...Plasma catheter 104a...Aperture 400...Plasma guide wire 403…Tip 421…First connection terminal 421a...Contact part 422…Second connection terminal 441…First cover part 441a...first tip surface 441c…Inside 441d...Groove for electrode 441e…Tip side recess 441f…Base end recess 441fC…Base end recess 441g…Seal part 441i…hole 441j…Shell 441k…Inner shell 442…Second cover part 442c…Inner surface 442d...Groove for electrode 442e…Tip side recess 442f, 442fC…Base end recess 442g…Sealed part 442h…Button section 442i…Hook part 442j…Outer shell 442k…Inner shell 444...Connection part 444a…shaft 444b, 444c...Rotation support part 500…RF Generator 501, 502...Terminals 504, 506... Cable connector 505…Cable 522, 522A, 522C...Tapered section 524...Spiral groove part 526…Lead wire recess 528…Tip side support part 528A, 528B…Terminal support part 528c…Second component 528l…First component 528s…Third component 542, 542C...Support part 544…Protrusion

Claims

1. A catheter comprising: A hollow shaft; a tip electrode provided at a tip portion of the hollow shaft; a proximal electrode provided at a proximal end of the hollow shaft and electrically connected to the distal electrode via the hollow shaft; a connection section configured to be detachable from the base electrode, electrically connecting an external voltage output device and the base electrode via a lead wire when attached to the base electrode, and including a covering section that covers the base electrode when attached to the base electrode; A grip portion provided at a base end of the hollow shaft, The connection portion constitutes the grip portion, The catheter further comprises: a replacement part which is detachable from the base electrode, the connection part is not attached to the base electrode, and when the replacement part is attached to the base electrode in place of the connection part, the base electrode and the voltage output device are not electrically connected to each other; catheter.

2. 2. The catheter of claim 1, The covering portion is a first cover portion having a first connection terminal to be connected to the lead wire; a second cover portion connected to the first cover portion by a connecting portion having a hinge structure; The device is configured to be openable and closable. the first cover portion and the second cover portion are attached to the proximal electrode in a closed state in which the proximal electrode is sandwiched between the first cover portion and the second cover portion; When the electrode is in an open state, the electrode can be detached from the proximal electrode. The first connection terminal is The connection portion is disposed at a position where the connection portion comes into contact with the base electrode when the connection portion is attached to the base electrode. catheter.

3. 3. The catheter of claim 2, At least one of the first cover portion and the second cover portion is The base electrode is provided with an electrode groove into which the base electrode can be fitted, The electrode groove is When the connection portion is attached to the base electrode, the first connection terminal is disposed at a position where it comes into contact with the base electrode. catheter.

4. 4. The catheter of claim 3, At least one of the first cover portion and the second cover portion includes a seal portion surrounding an outer periphery of the electrode groove portion. catheter.

5. A catheter according to any one of claims 1 to 4, The gripping portion is A tip gripping portion disposed at a tip of the gripping portion; A base end gripping portion disposed at a base end of the gripping portion; An intermediate gripping portion disposed between the distal gripping portion and the proximal gripping portion, The connecting portion and the alternative portion each constitute the intermediate gripping portion when attached to the proximal electrode. catheter.

6. 6. The catheter of claim 5, The base end gripping portion is a support portion provided on a distal end side of the base end grip portion and configured to fix and support the base end electrode; The support portion has a protrusion that protrudes in a direction from a central axis of the hollow shaft toward an outer periphery of the grip portion, The intermediate gripping portion is A recess is provided to fit into the support portion of the base end grip portion. catheter.

7. A catheter according to any one of claims 5 and 6, The tip gripping portion is It has a tapered section that narrows toward its tip, The tapered portion has a spiral groove portion formed in a spiral groove shape on a surface thereof. catheter.

8. The catheter according to any one of claims 5 to 7, The tip gripping portion is When the intermediate gripping portion is formed by the connection portion, the intermediate gripping portion can support the lead wire along a surface of the tip gripping portion, and has a lead wire recess on its surface into which the lead wire can be fitted. catheter.

9. A catheter according to any one of claims 5 to 8, the lead wire has a second connection terminal disposed at an end thereof and electrically connectable to the voltage output device; The catheter includes a terminal support portion at the distal end grip portion, the terminal support portion being capable of supporting the second connection terminal. catheter.

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