Heavy-insulated wires used during irreversible electroporation (IRE)

Abstract

The present invention is entitled "A conductor wire with heavy insulation for use during irreversible electroporation (IRE)". A conductor wire includes a metal wire, a first electrical insulating layer, and a second electrical insulating layer. The metal wire has a distal end. The first electrical insulating layer covers the metal wire. The second electrical insulating layer covers the distal end of the conductor wire, wherein the breakdown voltage of the second electrical insulating layer is greater than the breakdown voltage of the first electrical insulating layer.

Description

Technical Field

[0001] This invention relates generally to medical probes, and more specifically to electrically insulated cardiac probes. Background Technology

[0002] Electrical insulation for medical probes has been previously disclosed in patent literature. For example, PCT International Publication WO 2016 / 064753 describes a segmented metal guidewire suitable for MRI catheter insertion. The disclosed guidewire comprises multiple short conductive metal segments, each short enough to not resonate during MRI. The conductive segments are electrically insulated from each other and mechanically coupled end-to-end via connectors (such as stiffness-matching connectors) to provide a sufficiently long, robust, and flexible guidewire for catheter insertion that does not resonate during MRI.

[0003] As another example, U.S. Patent Application Publication 2013 / 0090647 describes an ablation catheter configured to be navigated through a blood vessel to ablate tissue. The ablation catheter includes an elongated catheter shaft having a proximal end and a distal end. An electrode is positioned near the distal end of the elongated shaft and is configured to deliver radiofrequency energy into the vessel wall. An electrically insulated tip at the distal end of the catheter keeps the electrode away from the vessel wall. Summary of the Invention

[0004] An embodiment of the present invention provides a guidewire comprising a metal wire, a first electrically insulating layer, and a second electrically insulating layer. The metal wire has a distal end. The first electrically insulating layer covers the metal wire. The second electrically insulating layer covers the distal end of the guidewire, wherein the breakdown voltage of the second electrically insulating layer is greater than the breakdown voltage of the first electrically insulating layer.

[0005] In some implementations, the combined breakdown voltage of the first and second electrical insulating layers is higher than the predefined voltage used in irreversible electroporation (IRE).

[0006] In some embodiments, the guidewire also includes a medical device coupled to the distal edge of the guidewire. In other embodiments, the medical device is a surgical instrument.

[0007] According to another embodiment of the invention, a method is further provided, comprising inserting a guidewire into a patient's heart, wherein the guidewire comprises: (a) a metal wire having a distal end; (b) a first electrical insulating layer covering the metal 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 the breakdown voltage of the first electrical insulating layer. An ablation catheter is inserted into the heart, the ablation catheter being positioned 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 implementations, the distal ends of the ablation catheter and guidewire are in physical contact.

[0009] In some implementations, inserting the ablation catheter involves guiding the IRE catheter via a guidewire.

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

[0011] According to another embodiment of the invention, a manufacturing method is also provided, the method comprising providing a metal wire having a distal end. The metal wire is covered with a first electrical insulating layer. The distal end of the wire is covered 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.

[0012] The invention will be more fully understood through the following detailed description of embodiments thereof, taken in conjunction with the accompanying drawings, wherein: Attached Figure Description

[0013] Figure 1 This is a schematic diagram of a cardiac catheterization system including an irreversible electroporation (IRE) subsystem according to an embodiment of the present invention;

[0014] Figure 2 It is according to the embodiment of the present invention and Figure 1 A schematic side view of a guidewire used in the system, the guidewire including a heavy-electric insulation shield at its distal end; and

[0015] Figure 3 This is a schematic illustration of an embodiment of the present invention. Figure 2 A flowchart of the method for manufacturing the guidewire. Detailed Implementation

[0016] Overview

[0017] Guidewires used in invasive procedures on internal organs (such as heart surgery) are typically formed as long, thin metal wires (e.g., stainless steel and / or nitinol wire). In some cases, guidewires may be formed as coils. Such guidewires can be used to deploy, for example, surgical instruments or implants. While guidewires can be electrically insulated, for example by being coated with Teflon, such insulation may not be able to withstand high voltages.

[0018] Some invasive procedures may also involve performing irreversible electroporation (IRE), also known as pulsed field ablation (PFA), at the treatment site, such as during cardiac surgery. For this, an additional ablation catheter is inserted into the organ. Such catheters are equipped with one or more electrodes at their distal end, which are used to apply IRE pulses with a typical value of 2 kV or greater. If the guidewire used during the IRE procedure comes into contact with the electrode delivering the IRE pulse, the operator holding the guidewire is at risk of electric shock.

[0019] The embodiments of the invention described below provide a guidewire with additional electrical insulation at its distal end (e.g., 15 cm from the farthest end of the guidewire). The insulation material and thickness are selected to withstand the high voltages used for IRE or PFA.

[0020] In some embodiments, the disclosed electrically insulated guidewire is used to guide an IRE catheter into a pulmonary vein (PV). In such procedures, the guidewire is inserted into the PV through a channel in a catheter (e.g., a balloon catheter), and the balloon catheter advances through the guidewire to the target PV for ablation. During this procedure, the guidewire may bend and come into direct contact with the ablation electrodes of the catheter or be close to high-voltage pulsed field electrodes. When ablation energy is applied, some energy may escape through the guidewire, reaching the proximal end of the guidewire and causing electric shock to the user. Insulating the guidewire as in the disclosed technology eliminates this hazard. Re-insulation also needs to prevent energy release from the user in contact with the guidewire to the heart, and thus prevent any charged object (e.g., a metallic object) in contact with the proximal end of the guidewire from transferring unwanted energy to the heart.

[0021] In some embodiments, the guidewire includes a first insulating layer and a second insulating layer, the first insulating layer covering the aforementioned metal wire and the second insulating layer covering the distal end of the guidewire, wherein the breakdown voltage of the second insulating layer is greater than the breakdown voltage of the first insulating layer. The combined breakdown voltage of the first and second insulating layers is higher than the voltage used in the IRE.

[0022] In some embodiments, one or both of these insulating layers are implemented, for example, by anodizing the guidewire. In some embodiments, the guidewire has a single insulating layer along its entire length inserted into the body, which may have a uniform or non-uniform thickness. Such insulation 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, thereby eliminating the need for additional insulating layers.

[0023] By providing heavily insulated guidewires, invasive medical procedures using IREs can be made safer.

[0024] System Description

[0025] Figure 1 This is a schematic diagram of a cardiac catheterization system 20 including an irreversible electroporation (IRE) subsystem according to an embodiment of the present invention. System 20 is used for invasive cardiac treatments involving the use of an IRE catheter 32 and a guidewire 22 (both shown in illustration 25). As shown, the IRE catheter 32 includes an electrode 62 configured to apply a high-voltage (e.g., 2 kV) IRE pulse to ablate cardiac tissue. The guidewire 22 has a wire at its core (the wire is... Figure 2 (As shown in the diagram), the wire is covered with a first electrical insulation layer 35. The guidewire 22 has a distal end 50, which is further covered with a heavy electrical insulation layer 55. The guidewire can be used in a variety of applications, such as for carrying invasive surgical instruments or implants.

[0026] Guidewire 22 is inserted into heart 26 through sheath 23. Physician 30 navigates guidewire 22 to the target location within heart 26 by manipulating the guidewire and / or flexing it from sheath 23 using a manipulator near the proximal end of the guidewire.

[0027] In the illustrated embodiment, the IRE catheter 32 is also inserted into the heart using a shaft 42, with the electrode 62 of the IRE catheter 32 located near the distal end 50 of the guidewire. The IRE electrode 62 is connected to the drive circuitry in the console 24 via a wire extending through the shaft 42.

[0028] The console 24 includes a processor 41 (typically a general-purpose computer) with a suitable front-end and electrical interface circuitry 37 for receiving electrical position signals from a patch 49. The processor 41 is connected to the patch 49 via a wire extending through a cable 39, which is attached to the chest skin of the patient 26. The console 24 drives a display 27 that shows the position of a catheter 32 within the heart 26.

[0029] The catheter position sensing method of System 20 is used in various medical applications, such as CARTO manufactured by Biosense Webster. TM The system is implemented in a manner described in detail in U.S. Patent 8456182, the disclosure of which is incorporated herein by reference.

[0030] Processor 41 is typically programmed in software to perform the functions described herein. This software may be downloaded to a computer electronically via a network, or alternatively or additionally set and / or stored on a non-transitory tangible medium, such as magnetic storage, optical storage, or electronic storage.

[0031] Guide wires with heavy insulation used during IRE

[0032] Figure 2 It is according to the embodiment of the present invention and Figure 1 A schematic side view of the guide wire 22 used in the system 20, which includes a heavy electrical insulation shield 55 at its distal end 50.

[0033] As shown in the figure, the conductor 22, which is typically made of metal wire 52, is covered with a first standard electrical insulation layer 35. As shown in the figure, only the distal end 50 is further covered with a heavy insulation layer 55.

[0034] The breakdown voltage of layer 55, alone or in combination with the breakdown voltage of layer 35, is high enough to insulate wire 52 from IRE voltage.

[0035] In an exemplary embodiment, the diameter of the wire 52 is in the range of 1 micrometer to 500 micrometers. The insulating layer 35 may be made of, for example, PTFE, polyurethane, polyamide, or without an insulating material.

[0036] Insulating layer 35 may have a thickness ranging from 1 micrometer to 500 micrometers. Insulating layer 55 may be made of, for example, ethylene tetrafluoroethylene (ETFE), silicone rubber (SR), perfluoroalkoxy (PFA), fluorinated ethylene propylene (FEP), or thermoplastic elastomer (TPE), and may have a thickness ranging from 1 micrometer to 500 micrometers. The length of the section of the guidewire covered by layer 55 may, for example, range from 10 mm to 150 mm. All the above figures and materials are given by way of example only. In alternative embodiments, any other suitable configuration may be used.

[0037] Figure 2 The guidewires described herein have been highly simplified for clarity of concept. For example, guidewire 22 may carry diagnostic and / or surgical devices at its distal edge, neither of which is shown.

[0038] Figure 3 This is a schematic illustration of an embodiment of the present invention. Figure 2 A flowchart of a method for manufacturing the guide wire 22 is provided. The process begins at a metal wire receiving step 72, where a bare metal wire, such as metal wire 52, is received. Next, at a first insulation step 74, the guide wire 22 is covered (e.g., coated) with a first electrical insulating material layer (such as Teflon).

[0039] At the second insulation step 76, the distal end 50 of the guide wire 22 is further coated with a heavy electrical insulation layer 55. The insulation material and thickness used in step 55 are selected to electrically isolate the metal guide wire from very high voltages (e.g., 2 kV). An example of layer 55 is an ethylene tetrafluoroethylene (ETFE) sleeve approximately 0.14 mm thick.

[0040] Figure 3The exemplary manufacturing methods shown are chosen purely for clarity of concept. Alternative or additional steps (such as the use of epoxy resin) may also be included, but these steps have intentionally been omitted in the disclosure to provide a more simplified flowchart. While the embodiments described herein are primarily geared towards invasive cardiac procedures involving IREs, the methods and systems described herein can also be used in other applications requiring the application of IREs, such as in neurology.

[0041] It should be understood that the above embodiments are cited by way of example, and the invention is not limited to the specific content shown and described above. Rather, the scope of the invention includes combinations and sub-combinations of the various features described above, as well as variations and modifications thereof, which will occur to those skilled in the art upon reading the above description, and which are not disclosed in the prior art. Documents incorporated herein by reference are considered an integral part of this application, except that if any terminology defined in such incorporated documents conflicts with the definitions expressly or implicitly given in this specification, only the definitions in this specification shall be considered.

Claims

1. A guidewire, the guidewire comprising: A metal wire having a distal end; A first electrical insulating layer covers the metal wire including the distal end; and A second electrical insulating layer covers the distal end of the guidewire, wherein the breakdown voltage of the second electrical insulating layer is greater than the breakdown voltage of the first electrical insulating layer, wherein the first and second electrical insulating layers each have a thickness in the range of 1 micrometer to 500 micrometers, and wherein the combined breakdown voltage of the first and second electrical insulating layers is 2kV or greater.

2. The guidewire according to claim 1, wherein the guidewire further comprises 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 guidewire, the method comprising: Provides a metal wire with a distal end; The metal wire, including the distal end, is covered with a first electrical insulating layer; as well as The distal end of the guidewire is covered with a second electrical insulating layer, wherein the breakdown voltage of the second electrical insulating layer is greater than that of the first electrical insulating layer, wherein the first electrical insulating layer and the second electrical insulating layer each have a thickness in the range of 1 micrometer to 500 micrometers, and wherein the combined breakdown voltage of the first electrical insulating layer and the second electrical insulating layer is 2kV or greater.

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