Guide wire and method for manufacturing the same

Abstract

To provide a guidewire used as an electrically insulated cardiac probe.SOLUTION: A guidewire 22 includes a metal wire, a first electrically insulating layer, and a second electrically insulating layer. The metal wire has a distal end 50. The first electrically insulating layer covers the wire. The second electrically insulating layer covers the distal end 50 of the guidewire 22, where a breakdown voltage of the second electrically insulating layer is larger than that of the first electrically insulating layer. Further, a combined breakdown voltage of the first and second electrically insulating layers is higher than a voltage used in irreversible electroporation (IRE).SELECTED DRAWING: Figure 1

Description

Technical Field

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[0001] The present invention generally relates to medical probes, and more specifically to an electrically insulated heart probe.

Background Art

[0002] Electrical insulation for medical probes has been previously proposed in patent documents. For example, International Publication No. 2016 / 064753 describes a segmented metal guide wire suitable for MRI catheterization. The disclosed guide wire includes a plurality of short conductive metal segments that are each short enough not to resonate during MRI. The conductive segments are electrically insulated from each other and are mechanically coupled end-to-end via a connector, such as a connector with a matching rigidity, to provide a sufficiently long and strong flexible guide wire for catheterization that does not resonate during MRI.

[0003] As another example, US Patent Application Publication No. 2013 / 0090647 describes an ablation catheter configured to be guided intravascularly for ablating tissue, the ablation catheter including a long catheter shaft having a proximal end and a distal end. An electrode is located near the distal end of the long shaft and is configured to transmit high-frequency energy into the vessel wall. An electrically insulating tip at the distal end of the catheter maintains the electrode away from the vessel wall.

Summary of the Invention

Means for Solving the Problems

[0004] One embodiment of the present invention provides a guide wire including a metal wire, a first electrical insulation layer, and a second electrical insulation layer. The metal wire has a distal end. The first electrical insulation layer covers the wire. The second electrical insulation layer covers the distal end of the guide wire, and the breakdown voltage of the second electrical insulation layer is greater than the breakdown voltage of the first electrical insulation layer.

[0005] In some embodiments, the combined breakdown voltage of the first and second electrical insulation layers is higher than a predetermined voltage used in irreversible electroporation (IRE).

[0006] In some embodiments, the guidewire further includes a medical device coupled to the distal end of the guidewire. In another embodiment, the medical device is a surgical instrument.

[0007] According to another embodiment of the present invention, an additional method is provided which includes inserting a guidewire into a patient's heart, the guidewire comprising (a) a metal wire having a distal end, (b) a first electrical insulating layer covering the wire, and (c) a second electrical insulating layer covering the distal end of the guidewire, wherein the breakdown voltage of the second electrical insulating layer is greater than that of the first electrical insulating layer. An ablation catheter is inserted into the heart near the distal end of the guidewire. An IRE pulse is applied near the distal end of the guidewire using an IRE catheter.

[0008] In some embodiments, the distal ends of the ablation catheter and guidewire are in physical contact.

[0009] In some embodiments, inserting the ablation catheter includes guiding the IRE catheter on a guidewire.

[0010] In some embodiments, the ablation catheter is an irreversible electroporation (IRE) catheter.

[0011] According to another embodiment of the present invention, a manufacturing method is further provided which includes providing a metal wire having a distal end. The wire is covered with a first electrical insulating layer. The distal end of the guide wire is covered with a second electrical insulating layer, the breakdown voltage of the second electrical insulating layer being greater than that of the first electrical insulating layer.

[0012] This invention will be more fully understood by considering the following "Modes for Carrying Out the Invention" in conjunction with the drawings. [Brief explanation of the drawing]

[0013] [Figure 1] This is a schematic diagram of a cardiac catheterization system including an irreversible electroporation (IRE) subsystem according to one embodiment of the present invention. [Figure 2] Figure 1 shows a schematic side view of a guide wire used with the system according to one embodiment of the present invention, the guide wire including a heavy electrical insulation cover at its distal end. [Figure 3] This flowchart schematically shows a method for manufacturing the guide wire shown in Figure 2 according to one embodiment of the present invention. [Modes for carrying out the invention]

[0014] Overview Guidewires used in invasive procedures involving internal organs, such as cardiac surgery, are typically formed as elongated metal wires (e.g., stainless steel and / or nitinol). In some cases, guidewires may be formed as wire coils. Such guidewires may be used, for example, to position surgical instruments or implants. Guidewires may be electrically insulated by coating them with, for example, Teflon, but such insulation may not withstand high voltages.

[0015] Some invasive techniques may further involve performing irreversible electroporation (IRE), also known as pulsed-field ablation (PFA), at the treatment site, as may be done during cardiac surgery. For this purpose, an additional ablation catheter may be inserted into the organ. Such a catheter has one or more electrodes attached to its distal end, which are used to apply IRE pulses of a typical magnitude of 2 kV or greater. If the guidewire used during the IRE procedure comes into contact with the electrodes transmitting the IRE pulses, this poses a risk of electrocution to the operator holding the guidewire.

[0016] Embodiments of the present invention described below provide a guidewire with additional electrical insulation over its distal end, for example, over the furthest 15 cm of the guidewire. The insulating material and thickness are selected to withstand the high voltages used in IRE or PFA.

[0017] In some embodiments, the electrically insulated guidewires disclosed are used to guide an IRE catheter into a pulmonary vein (PV). In such a procedure, the guidewire is inserted through a channel in the catheter (e.g., a balloon catheter) to the PV, and the balloon catheter is advanced along the guidewire to the PV target for ablation. During this process, the guidewire may bend and come into direct contact with the ablation electrode of the catheter or come into close proximity to a high-voltage pulsed-field electrode. When ablation energy is applied, some of the energy may pass out of the body through the guidewire, reach the proximal end of the guidewire, and cause electrocution of the user. This hazard is eliminated by insulating the guidewire, as in the disclosed technology. Another need for heavy insulation is to prevent the release of energy from the user in contact with the guidewire to the heart, and to prevent any excitation (e.g., a metallic object) in contact with the proximal end of the guidewire from passing unwanted energy to the heart.

[0018] In some embodiments, the guidewire includes a first insulating layer covering the aforementioned metal wire and a second insulating layer covering the distal end of the guidewire, wherein the breakdown voltage of the second insulating layer is greater than that of the first insulating layer. The combined breakdown voltage of the first and second insulating layers is higher than the voltage used in IRE.

[0019] In some embodiments, one or both of the insulating layers are implemented, for example, by anodizing the guidewire. In some embodiments, the guidewire has a single insulating layer along its entire length that is inserted into the human body, which may be of uniform or non-uniform thickness. Such insertion prevents, for example, the unintentional conduction of electrical pulses to unspecified tissue locations within the body. In some embodiments, the guidewire itself is made of a non-conductive material, eliminating the need for an additional insulating layer.

[0020] By providing a heavily insulated guidewire, medical invasive procedures using IREs can be made safer.

[0021] System Description Figure 1 is a schematic drawing of a cardiac catheterization system 20 including an irreversible electroporation (IRE) subsystem according to one embodiment of the present invention. The system 20 is used for invasive cardiac procedures involving the use of an IRE catheter 32 and a guidewire 22 (both shown in inset 25). As can be seen, the IRE catheter 32 incorporates an electrode 62 configured to apply a high voltage (e.g., 2kV) to ablate cardiac tissue. The guidewire 22 has a metal wire whose core (the wire shown in Figure 2) is covered with a first electrical insulation layer 35. The guidewire 22 has a distal end 50 that is further covered with a heavy electrical insulation layer 55. The guidewire can be used for a variety of purposes, such as transporting invasive surgical instruments or implants.

[0022] The guidewire 22 is inserted into the heart 26 through the sheath 23. The physician 30 guides the guidewire 22 to the target site in the heart 26 by manipulating the guidewire using a manipulator near the proximal end of the guidewire and / or deflection from the sheath 23.

[0023] In the illustrated embodiment, the IRE catheter 32 is also inserted into the heart using the shaft 42 with the electrodes 62 of the IRE catheter 32 disposed in the vicinity of the distal end 50 of the guide wire. The IRE electrodes 62 are connected to a drive circuit within the console 24 by wires that extend through the shaft 42.

[0024] The console 24 includes a processor 41 having a suitable front-end electrical interface circuit 37 for receiving electrical position signals from the patch 49, which is typically a general-purpose computer. The processor 41 is connected to a patch 49 attached to the patient 26's chest skin by wires that extend through the cable 39. The console 24 drives a display 27 that indicates the position of the catheter 32 within the heart 26.

[0025] The method of catheter position sensing using the system 20 is implemented in various medical applications, for example, in the CARTO (trademark) system manufactured by Biosense Webster, which is described in detail in U.S. Patent No. 8,456,182, the disclosure of which is incorporated herein by reference.

[0026] The processor 41 is typically programmed with software to perform the functions described herein. The software can be downloaded to the computer in electronic form, for example, over a network, or alternatively or additionally, provided and / or stored on a non-transitory tangible medium such as magnetic memory, optical memory, or electronic memory.

[0027] A guide wire having heavy insulation for use during IRE FIG. 2 is a schematic side view of a guide wire 22 used with the system 20 of FIG. 1, according to an embodiment of the present invention, the guide wire including a heavy electrical insulation cover 55 at its distal end 50.

[0028] As can be seen, the guide wire 22, typically made of metal wire 52, is covered with a first standard electrical insulation layer 35. As can be seen, only the distal end 50 is further covered with a double insulation layer 55.

[0029] Either the breakdown voltage of layer 55 alone, or the breakdown voltage of layer 55 combined with layer 35, is high enough to isolate wire 52 from the IRE voltage.

[0030] In exemplary embodiments, the diameter of the metal wire 52 is in the range of 1 micrometer to 500 micrometers. The insulating layer 35 may be made of, for example, PTFE, polyurethane, or polyamide, or insulation may not be used at all.

[0031] The insulating layer 35 may have a thickness in the range of 1 micrometer to 500 micrometers. The insulating layer 55 may be made from, for example, ethylene tetrafluoroethylene (ETFE), silicone rubber (SR), perfluoroalkoxy (PFA), fluorinated ethylene propylene (FEP), or thermoplastic elastomer (TPE), and may have a thickness in the range of 1 micrometer to 500 micrometers. The length of the section of guidewire covered with layer 55 may be, for example, in the range of 10 mm to 150 mm. All figures and materials described above are given purely as examples. In alternative embodiments, any other suitable configuration may be used.

[0032] The guidewire illustrated in Figure 2 is highly simplified for the sake of clarity. For example, guidewire 22 may carry diagnostic and / or surgical instruments at its distal end, neither of which are shown.

[0033] Figure 3 is a schematic flowchart illustrating a method for manufacturing the guide wire 22 shown in Figure 2 according to one embodiment of the present invention. The process begins with receiving an exposed metal wire, such as the wire 52, in a metal guide wire receiving step 72. Next, the guide wire 22 is covered (e.g., coated) with a first layer of an electrical insulating material, such as Teflon, in a first insulation step 74.

[0034] In the second insulation step 76, the distal end 50 of the guidewire 22 is further covered with heavy electrical insulation 55. The insulating material and thickness used in step 55 are selected to electrically insulate the metal guidewire from very high voltages (e.g., 2kV). An example of layer 55 is a sleeve of ethylene tetrafluoroethylene (ETFE) with a thickness of approximately 0.14 mm.

[0035] The exemplary manufacturing method shown in Figure 3 is selected purely for the purpose of clarifying the concept. Alternative or additional steps (such as the use of epoxy) may be included, which have been intentionally omitted from the disclosure herein in order to provide a more simplified flowchart. While the embodiments described herein primarily address invasive cardiac procedures involving IRE, the methods and systems described herein may also be used in other applications requiring the application of IRE, such as neurology.

[0036] The embodiments described above are illustrative examples, and it will be understood that the present invention is not limited to those specifically illustrated and described above. Rather, the scope of the present invention includes both combinations and partial combinations of the various features described above, as well as variations and modifications thereof not disclosed in the prior art, which would be conceivable to those skilled in the art by reading the foregoing description. Documents incorporated into this patent application by reference shall be considered integral parts of this application, except that, in such incorporated documents, only the definitions provided herein shall be considered to the extent that any term is defined in a manner inconsistent with the definitions provided herein, either explicitly or implicitly.

[0037] [Implementation Method] (1) A guide wire, A metal wire having a distal end, A first electrical insulating layer covering the wire, A second electrical insulating layer covering the distal end of the guide wire, wherein the breakdown voltage of the second electrical insulating layer is greater than that of the first electrical insulating layer. A guide wire equipped with the following features. (2) The guide wire according to Embodiment 1, wherein the combined breakdown voltage of the first electrical insulating layer and the second electrical insulating layer is higher than a predetermined voltage used in irreversible electroporation (IRE). (3) The guide wire according to Embodiment 1, further comprising a medical device coupled to the distal edge of the guide wire. (4) The guide wire according to Embodiment 3, wherein the medical device is a surgical instrument. (5) A method, The procedure involves inserting a guidewire into the patient's heart, wherein the guidewire is A metal wire having a distal end, A first electrical insulating layer covering the wire, The device comprises a second electrical insulating layer covering the distal end of the guide wire, wherein the breakdown voltage of the second electrical insulating layer is greater than that of the first electrical insulating layer. The ablation catheter is inserted into the heart near the distal end of the guidewire, A method comprising applying an IRE pulse near the distal end of the guidewire using an IRE catheter.

[0038] (6) The method according to embodiment 5, wherein the distal end of the ablation catheter and the guidewire are in physical contact. (7) The method of embodiment 5, wherein inserting the ablation catheter includes guiding the ablation catheter onto the guidewire. (8) The method according to embodiment 5, wherein the ablation catheter is an irreversible electroporation (IRE) catheter. (9) A method of manufacture, To provide a metal wire having a distal end, Covering the wire with a first electrical insulating layer, A manufacturing method comprising covering the distal end of the guide wire with a second electrical insulating layer, wherein the breakdown voltage of the second electrical insulating layer is greater than the breakdown voltage of the first electrical insulating layer.

Claims

1. A guide wire used in an irreversible electroporation method, A metal wire having a distal end, A first electrical insulating layer covering at least the distal end of the metal wire, A second electrical insulating layer covering the distal end covered by the first electrical insulating layer, wherein the breakdown voltage of the second electrical insulating layer is greater than that of the first electrical insulating layer. Equipped with, A guide wire in which each of the first and second electrical insulating layers has a thickness ranging from 1 micrometer to 500 micrometers, and the combined breakdown voltage of the first and second electrical insulating layers is 2 kV or more.

2. The guidewire according to claim 1, further comprising a medical device coupled to the distal edge of the guidewire.

3. The guidewire according to claim 2, wherein the medical device is a surgical instrument.

4. A method for manufacturing a guide wire used in irreversible electroporation, To provide a metal wire having a distal end, The distal end of the metal wire is covered with at least the first electrical insulating layer, The method includes covering the distal end covered with the first electrical insulating layer with a second electrical insulating layer, wherein the breakdown voltage of the second electrical insulating layer is greater than the breakdown voltage of the first electrical insulating layer. A manufacturing method wherein each of the first and second electrical insulating layers has a thickness ranging from 1 micrometer to 500 micrometers, and the combined breakdown voltage of the first and second electrical insulating layers is 2 kV or more.

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