CN111184553A

CN111184553A - High coverage low profile electrode assembly for angioplasty shock waveguides

Info

Publication number: CN111184553A
Application number: CN201911253403.6A
Authority: CN
Inventors: 艾睿; 吴献蔚; 彭惠群
Original assignee: Spectron Medical Technology Shanghai Co Ltd
Current assignee: Spectron Medical Technology Shanghai Co Ltd
Priority date: 2019-04-29
Filing date: 2019-12-09
Publication date: 2020-05-22
Anticipated expiration: 2039-12-09
Also published as: CN111184553B

Abstract

A shockwave generating system for an angioplasty catheter includes an elongated member, wire electrodes, a non-conductive gap, each wire electrode attached to an electrical output terminal of a high voltage power supply by a wire extending from a terminal on an outer surface of the elongated member to the wire electrode. The system is an electrode assembly for a shock wave-producing angioplasty catheter for treatment of calcified arteries. The shock wave is impulsive in nature and is capable of striking and disintegrating hard calcified platelets deposited on the inner wall of the artery. Once these deposits are broken, the space in the lumen of the artery is enlarged, thereby improving blood flow.

Description

High coverage low profile electrode assembly for angioplasty shock waveguides

Technical Field

The invention belongs to the field of medical instruments, and particularly relates to a high-coverage low-profile electrode assembly for an angioplasty shock waveguide.

Background

Atherosclerosis is the contraction and hardening of arteries due to platelet accumulation. This platelet is composed of fibrotic tissue, fat and calcium as the disease progresses. This accumulation of calcified platelets impedes the normal flow of blood, thereby reducing the supply of oxygen and nutrients to the body. Of particular interest are arterial diseases that supply blood to key parts of the body, including the brain, heart and limbs.

Angioplasty is a technique for opening a constricted artery that is afflicted with platelet accumulation using an expandable balloon mounted on a catheter. A catheter is percutaneously inserted into the vasculature and the balloon is pressurized to radially compress the calcified platelets. The resulting artery is then enlarged, thereby improving blood flow. While this treatment is a standard treatment, it does not eliminate potentially calcified platelets in the diseased artery. Thus, it may be desirable to modify calcium deposition by rupturing or softening to substantially enlarge the artery and improve blood flow.

Disclosure of Invention

The present invention describes an electrode assembly for a shock wave-producing angioplasty catheter for the treatment of calcified arteries. The shock wave is impulsive in nature and is capable of striking and disintegrating hard calcified platelets deposited on the inner wall of the artery. Once these deposits are broken, the space in the lumen of the artery is enlarged, thereby improving blood flow. In contrast to traditional balloon angioplasty (where the lesion is enlarged primarily by high pressure mechanical compression of the congelation-like platelets, which often leads to exfoliation), the purpose of this device is to break down the calcium itself. This can increase vascular compliance and allow the artery to receive further intervention, such as stenting, or as a stand alone treatment.

One example of a shock wave angioplasty catheter may include an elongated collapsible balloon sized to fill the luminal space of an arterial vessel and to be in physical contact with calcified platelets when inflated with a liquid. The balloon may contain a plurality of shock wave sources therein. Shock waves are generated from these shock wave sources when the balloon is inflated within the atherosclerotic region of the artery to rupture the calcium deposits in contact.

The catheter generates shock waves by using electrodes. In this case, the single electrode of the device comprises a first end face and a second end face. The shock wave source includes an electrode assembly composed of one end face of a first electrode and one end face of a second electrode disposed adjacent thereto. A non-conductive gap exists between the end face of the first electrode and the adjacent end face of the second electrode. The electrodes are coaxially arranged relative to each other, along an outer surface of the axially extending elongated member. This configuration allows the electrode to exhibit a low profile along the treatment length of the shockwave angioplasty catheter, thereby enabling its access and use in smaller arteries, such as the cardiac artery.

Arcing between the electrode end faces across the non-conductive gap is the primary mechanism for generating the shock wave. The ionization event across the electrodes in the liquid medium forms a channel through which a large discharge current will pass. The generated cavitation bubbles rapidly expand and collapse, producing a shock wave that continues to pass through the liquid medium in the balloon to destroy calcium.

The electrodes may also be coated with an insulating material to prevent current leakage and arcing from unintended areas along the length of the electrodes. In one example, an insulative length of material is disposed over each electrode to completely encapsulate the middle portion and expose the first and second ends. In another example, an insulating length of material is disposed over the electrodes, completely encapsulating them so that only one end is exposed. These configurations allow the electrode to generate an arc discharge only at the end face thereof. The arrangement of the electrodes and the location of the insulating sleeve as described above serve to promote the propagation of the shock wave in a radially outward manner.

The electrodes may form a closed series circuit with the high voltage power supply and be connected to the latter by means of wires. In one example, the apparatus may include a first wire and a second wire. The first wire may be connected to the first electrode and may be connected to a first terminal of a high voltage power supply. The second wire may be connected to the second electrode and to a second terminal of the high voltage power supply. This arrangement of the electrodes, their connecting lines and the high voltage power supply forms the above-mentioned series circuit through which a current can flow when a voltage drop is applied across the power supply.

The electrodes may also form a plurality of closed series circuits with the high voltage power supply. Here, the catheter may include a first wire, a second wire, and a third wire. The first lead may be connected to the first electrode and to a first terminal of a high voltage power supply with a reversible polarity. A second wire may be connected to the second electrode and to the second terminal of the high voltage power supply with a reversible polarity. A third wire may be connected to the third electrode and to the third terminal of the high voltage power supply with a reversible polarity. These electrodes with their associated leads may therefore be referred to as wired electrodes. With this configuration, it can be concluded that a series circuit can be established with the first and second electrodes, with the second and third electrodes and with the first, second and third electrodes, resulting in a total of three series circuits. It will be appreciated that as the number of wire electrodes increases, a greater number of series circuits may be added. For example, by adding a fourth electrode to which the fourth electrode is connected and which is connected to the fourth terminal of the high voltage power supply with a reversible polarity, the number of series circuits is increased to six. In addition to this, increasing the number of terminal electrodes may also increase the number of shock wave sources.

In each series circuit, current will flow from the positive terminal of the high voltage power supply to the system and then back to the power supply through the negative terminal. Since the terminals of the high voltage power supply have reversible polarity, current can flow in either direction between the two terminals as long as one terminal is positive and the other terminal is negative.

In each series circuit there are wired electrodes with associated wires which are connected to terminals of a high voltage power supply. However, each circuit may also include a non-conductive electrode without any associated conductive lines. These non-conducting electrodes may be arranged in series between any two conducting electrodes of opposite polarity. For example, a non-conducting electrode may be present between the positive and negative lead electrodes. In this case, a current flows from the positive terminal to the positive wiring electrode, and reaches the non-wiring electrode across the first non-conductive gap by arc discharge. The current then passes through the non-wiring electrode to its opposite end face and through the negative electrode by a second arc discharge. Therefore, the number of shock wave sources increases to two. It will be appreciated that any number of non-wired electrodes may be provided between any two wired electrodes of opposite polarity in any of the plurality of closed series circuits of the device. An increase in the number of non-wiring electrodes increases the number of shock wave sources. The advantage of this is evident when trying to construct a low profile catheter that is not affected by many wires running along its length. Thus, the number of shock wave sources can be increased without sacrificing the flexibility and maneuverability of the catheter.

The catheter also includes a patterned shock wave generating group trigger pattern. With the above-described features of multiple series circuits and multiple non-conducting electrodes, any number of shock wave sources may be grouped into a single plurality of series circuits. For example, three wiring electrodes constitute three series circuits and two shock wave sources. It can be divided into two series circuits of one shock wave source, each of which can be triggered in turn. Due to the reversible characteristic of the high-voltage power supply terminal, the first terminal electrode may become a positive electrode, and the second terminal electrode may become a negative electrode. This creates a series circuit with a first electrode and a second electrode, and the current flowing through will produce a shock wave at a single shock wave source. Reversing the polarity of the second electrode to positive and the polarity of the third electrode to negative will form a second series circuit with the second and third electrodes. The passing current will generate a shock wave at the second singular shock wave source. It should also be clear that the second electrode may not be assigned a polarity and may be electrically disconnected from the high voltage power supply. In this case, assigning opposite polarities to the first and third electrodes forms a series circuit with the first, second and third electrodes, and thus, the two shock wave sources generate shock waves when current passes therethrough. Thus, it should be appreciated that multiple adjacent shock wave sources may be triggered simultaneously in any desired order, with multiple wired and non-wired electrodes, and reversing the polarity of the terminals of the high voltage power supply. For example, ten electrodes may be disposed along the length of an elongate member extending within a catheter. Four are wired, with two non-wired electrodes between each pair. This allows the nine shock wave sources to be divided into three groups of three shock wave sources, each group constituting a closed series circuit. Each circuit can be separately opened to generate shock waves uniformly along different regions of the conduit. This brings the advantage of treating very long lesions. Throughout the procedure, the catheter will not have to be continuously advanced and retracted to cover the entire length of the lesion.

Drawings

FIG. 1 is a diagram illustrating how the invention described herein may be constructed. It takes the form of an angioplasty catheter, where 101 is an inflated angioplasty balloon located over the shock wave generation region. 102 represents the wiring harness from the electrode to the connector 104. 103 denotes a three-way port with one branch leading to a connector 104.

FIG. 2 is a close-up view of the shock wave generating region of the conduit. 201 is an angioplasty balloon shown containing

shock wave sources

203 and 204. The source of the shock wave is located on the elongate member 202 which extends.

Fig. 3 shows a low profile electrode of the shockwave generating device with the rear face 302 exposed in perspective. The front face is labeled 301.

Fig. 4 shows a configuration of a shock wave source, which is composed of a pair of

electrodes

401 and 402 whose end faces are adjacent to each other in the same plane. 403 is an extended elongated member on which the electrodes are disposed. 404 shows a non-conductive gap existing between the end faces of the two electrodes. 405 and 406 are insulating sleeves covering each electrode. 407 denotes the arc discharge from electrode 401 to electrode 402.

Fig. 5A shows a variation of the coverage of the insulating material 501, said insulating material 501 being sheathed on electrodes arranged on the extension elongated member 502. This covers the middle portion of the electrode and exposes ends 503 and 504 to the surrounding liquid medium in which the electrode is immersed.

Fig. 5B shows another variation in the coverage of the insulating material 505 over the electrodes. This covers the middle portion and one end of the electrode to expose only one end 506 of the electrode.

Fig. 6 shows in schematic form a representation of a series circuit layout of a single shock wave source. 604 is the source of the shock wave, which is generated. 607 and 608 are the terminals of the high voltage power supply 601 and both are reversible polarity.

Wires

605 and 606 connect them to

electrodes

602 and 603.

Fig. 7 depicts a configuration of three

wired electrodes

705, 701, and 707 that results in two

shock wave sources

708 and 709 and three possible series circuit paths.

Fig. 8 depicts a configuration of four wired electrodes resulting in three

shock wave sources

802, 803 and 804 and six possible series circuit paths.

Fig. 9 depicts a mixture of wired and non-wired electrodes in the same series circuit.

Non-conducting electrodes

901 and 902 are located between two conducting

wire electrodes

903 and 904.

Fig. 10A is based on fig. 8 and 9 and depicts one example of how multiple wired and non-wired electrodes may be combined into multiple series circuits along the length of a catheter or other elongate carrier member.

FIGS. 10B-F illustrate various ways in which groups of shockwave sources may be triggered. 1007 and 1008 depict a set of three shock wave sources at different locations on the device, respectively. The shock waves are represented by semi-elliptical lines emanating from each shock wave source. The schematic diagram is simplified to exclude high voltage power supplies. Instead, the polarity of the terminals is shown where appropriate to demonstrate the formation location of each circuit. As long as a series circuit is formed between the two terminal electrodes, a current can flow to generate an arc discharge, thereby generating a shock wave.

Detailed Description

Devices and systems are described for treating disease of atherosclerotic vessels with highly calcified platelet accumulation. The device is a shock wave generating angioplasty catheter system comprising a plurality of electrodes forming a shock wave source disposed along a distal end thereof. Figure 1 shows one such example of a shock wave generating catheter system. It is an enhancement of traditional balloon angioplasty catheters used to treat atherosclerotic arteries in humans. Whereas conventional balloon angioplasty uses an inflated balloon to mechanically compress calcified platelets and dilate the lumen of the blood vessel, the catheter of the present invention functions to add high coverage, low profile electrode assemblies that generate shock waves to disrupt calcification. These electrodes are located within the inflatable balloon 101 in the treatment area of the catheter and may be connected to a high voltage source outside the body by conductive leads 102 and connectors 104 that provide an electromotive force to conduct current and generate an arc discharge. The balloon 101 will be inflated with a liquid, such as saline or contrast agent, within the diseased artery to make good physical contact with the calcified platelets. After installation in place, the voltage drop across the high voltage power supply causes arcing at the electrodes, creating cavitation bubbles that expand and collapse rapidly. This produces a high pressure shock wave that propagates through the liquid filled balloon and strikes the calcified platelets.

The electrode is an integral part of the operation of the shock wave generating device. They may be constructed of any number or composition of electrically conductive materials (e.g., titanium, stainless steel or tungsten). A single catheter may contain multiple electrodes to perform its function of generating shock waves. Fig. 3 is a representation of a typical electrode to be used in a catheter. The electrode may have a cylindrical shape to conform to the elongate member on which it is disposed. The electrodes may also have different cross-sectional shapes, if desired, which conform to the cross-sectional shape of the elongate member. This will be particularly evident in embodiments of the device where the elongate member is a tube consisting of a plurality of lumens carrying guide wires and conductive wires, in which case it may be difficult in practice to manufacture a tube having a completely circular cross-sectional area. 301 is one end of the electrode and 302 is the other end. One end face may be proximal (closer to the operator) and the other end face distal (further from the operator).

The shock wave source is the component responsible for generating shock waves for treatment. Figure 4 shows the configuration of one such shock wave source. Each shock wave source is constituted by a distal end face of a proximal electrode and a proximal end face of an immediately adjacent distal electrode, which is arranged on the elongated member 403. The pair of electrodes are separated by a non-conductive gap 404. The non-contact separation of the electrodes is an important feature of the shock wave source as this is where the arc discharge 407 occurs. When current flows into electrode 401, a gas ionization path is formed in the liquid medium from one point on electrode 401 to another point on electrode 402. As the ionization event increases, the liquid becomes conductive, allowing a larger growing arc to traverse the path and pass through the next electrode. This phenomenon can produce cavitation bubbles near the electrode surface. The bubbles expand and contract rapidly, resulting in the formation of high pressure shock waves in a short time. The shock wave propagates through the liquid medium to the balloon surface, rupturing the calcium in contact. Fig. 4 shows arcing occurring at different points on two electrodes, but since the surfaces of the electrodes are flat and their surfaces are flat, arcing may terminate at any two points and at two points of two adjacent electrodes, except where covered by a surface. The insulating

sheaths

405 and 406 allow for more points to be made on the circumference of the catheter by allowing electrical discharges to occur at any time, with increased randomness, shock waves. Arranging the electrodes in an adjacent manner also simplifies the layout and reduces the volume within the device. Only a single layer of electrode material is required along the treatment region of the device. This makes it possible to obtain a low-profile device that is capable of increased flexibility and maneuverability within tortuous vasculature.

The insulation is the physical separation of the conductive surface of the electrode from the liquid medium in the inflated balloon. Fig. 5A shows one case of a non-conductive material 501 that is sleeved over the middle surface of the electrode. The insulating layer exposes only surfaces 502 and 503 near the ends of the electrodes. This will prevent unnecessary arcs from forming too far from the electrode gap. This configuration of insulation will allow this electrode to be located between two other electrodes, thus forming two electrodes across from each other, thus forming two shock wave sources. Fig. 5B shows another case where the insulating sheath 505 on the electrode exposes only one end 506. The configuration would be useful for electrodes intended to be located most proximally and most distally.

The main type of circuit used in the present invention is a series circuit, since the arcing frequency is highly uniform across all connected electrodes. The current flowing through each shock wave source is also kept consistent, thereby ensuring that the shock wave pressure is evenly distributed along the entire length of the conduit. Fig. 6 is a schematic diagram of a series circuit formed between an extracorporeal high voltage power supply 601 and two

electrodes

602 and 603 forming a shock wave source 604, which are connected by

conductive leads

605 and 606. The wire 605 is connected to the electrode 602 and one terminal 607. The source of the high voltage, and the terminal on the other end 608 of the wire 606, are in reversible polarity and alternate from positive to negative so that the direction of current flow is reversed for each applied voltage drop time. By doing so, the arc may jump from electrode 602 to electrode 603 in one case, and may proceed in another way in the following cases. This helps to even out the amount of wear generated on the two electrodes, thereby extending the life of the electrode assembly in the catheter during each procedure. To reduce complexity, the insulating sheath is not shown.

In addition to using a single series circuit, the catheter may also use multiple series circuits in combination. Fig. 7 is based on fig. 6. In fig. 6, a further electrode 701 is shown, said further electrode 701 being connected to a third terminal 702 of a high voltage supply via a third wire 703. It is observed that each electrode is connected by its own lead to a terminal on the high voltage power supply. These electrodes may therefore be referred to as wired electrodes. As shown in fig. 6, two terminal electrodes constitute the most basic series circuit through which current flows from one terminal and then returns to the next. As shown in fig. 7, three terminal electrodes form three possible series circuits. A positive state is assigned to terminal 704 and a negative state is assigned to terminal 702, forming a series

circuit comprising electrodes

705 and 701. The polarity of the terminal 702 is inverted to the positive polarity and the negative state is assigned to the terminal 706, forming another series circuit including the

electrodes

701 and 707. Finally, a positive state is assigned to the terminal 704 and a negative state is assigned to the terminal 706, forming a third series circuit comprising the

electrodes

705, 701 and 707. Thus, it can be seen that adding more wire electrodes increases the number of possible series circuits within the conduit, as shown in fig. 8. The fourth wired electrode 801 added to the setup would result in a total of six possible series circuits and increase the number of shock wave sources to three (802, 803 and 804). The next paragraph will detail the advantage of adding more series circuits.

In addition to adding wire electrodes to create more series circuits, non-wired electrodes can be added to each individual circuit to create a longer chain of electrodes along the length of the catheter. This, in turn, increases the number of shock wave sources. Fig. 9 shows two additional

non-wired electrodes

901 and 902 included in a series circuit formed between

wired electrodes

903 and 904. The two new electrodes are not physically connected to any other element in the circuit, but are simply arranged on the surface of the elongated member. The current of nail will cross the arc to the non-wired electrode and the arc continues to the next one through the wired electrode until it reaches the next wired electrode. It can thus be seen that any number of non-wired electrodes can be provided between two wired electrodes in such a series circuit, and current will be able to pass, given a sufficient potential difference provided at the high voltage supply. Fig. 10A is a detailed schematic diagram illustrating a potential use case of multiple series circuits and multiple non-conducting electrodes disposed within each series circuit. The combination of these two configurations creates the possibility of generating a shock wave generating device of considerable length without the burden of excessive wiring. This is particularly important in view of the need for as much space as possible within the elongate member that holds the load carrying wires, in addition to the necessary guidewire lumen. Fewer wires will impart greater flexibility, reduce the diameter of the device, and thus have greater ability to traverse tortuous vasculature.

The use of multiple series circuits and multiple non-wiring electrodes within each circuit also gives the ability to preferentially trigger the shock wave source depending on the series circuit in which they are located. Fig. 10B-F show a series of output possibilities based on the setup of fig. 10A. As described above, using the principle of reversing the polarity of the terminals and creating a separate series circuit from multiple terminal electrodes, fig. 10B first shows that two

non-wired electrodes

1001 and 1002 disposed between two

wired electrodes

1003 and 1004 form a first closed series circuit connected to the distributed positive and

negative terminals

1005 and 1006 of the high voltage power supply. The configuration is equivalent to three shock wave sources indicated by shock wave group 1007. This includes, for example, a first set of three shock wave sources at the distal end of the device. Fig. 10C is a similar arrangement, but

terminals

1008 and 1009 are activated, thereby triggering a second set 1010 of three shock wave sources in the middle portion of the catheter. It can thus be seen that different groups of shock wave sources can be triggered preferentially based on the polarity assignments on the different terminals, the group size being determined by the number of non-wiring electrodes in each series circuit. FIG. 10D shows the closest shockwave source set that is triggered. It can also be concluded that in some cases, by bypassing the terminal, both sets of shock wave sources can be triggered simultaneously, as shown in fig. 10E. Bypassing the two intermediate terminals would allow triggering all three groups of shock wave sources simultaneously, as shown in fig. 10F, which capability becomes advantageous for very long lesions. Having a long electrode array increases the number of shock wave sources, thereby increasing the length of the lesion that can be treated by the device. For example, a catheter having the arrangement shown in fig. 10A-F would not require advance and continuous retraction to cover long lesion lengths.

Claims

1. A shock wave generating system for an angioplasty catheter, comprising:

an axially extending elongated member having an outer surface;

a plurality (e.g., 2 to 10, e.g., 3) of wire electrodes disposed on the outer surface of the elongated member, wherein the electrodes are electrically arranged in a series configuration and are also arranged coplanar with one another;

a non-conductive gap between any two adjacent wired electrodes characterized by

Each wired electrode is attached to an electrical output terminal of a high voltage power supply by a wire extending from a terminal on an outer surface of the elongated member to the wired electrode.

2. The apparatus of claim 1, wherein the plurality of wired electrodes comprises three wired electrodes, wherein:

a first wire extending over the outer surface of the elongated member connecting a first terminal electrode to a first electrical output terminal of a high voltage power supply;

a second wire extending over the outer surface of the elongated member connecting a second terminal electrode to a second electrical output terminal of a high voltage power supply; and is

A third wire extending on the outer surface of the elongated member connects a third terminal electrode to a third electrical output terminal of a high voltage power supply.

3. The device of claim 1 or claim 2, further comprising one or more (e.g. 2 to 10) physically separated electrodes, wherein each physically separated electrode is disposed within the non-conductive gap between two adjacent wired electrodes, optionally wherein when two or more physically separated electrodes occupy the non-conductive gap between two adjacent wired electrodes then the non-conductive gap is also present between adjacent physically separated electrodes.

4. The apparatus of any preceding claim, wherein each electrical output terminal of the high voltage power supply has a selectively reversible polarity between positive and negative poles, such that a series circuit is formed between any two wired electrodes, which allows the resulting electrode pair to be triggered to generate a shockwave, optionally wherein the arrangement results in the ability to optionally trigger a shockwave source.

5. The device of claim 2 or claim 3, further comprising four wired electrodes, wherein a fourth wire extending over the outer surface of the elongate member connects a fourth electrode to a fourth electrical output terminal of a high voltage power supply.

6. A shock wave generating system for an angioplasty catheter, comprising:

an axially extending elongated member having an outer surface;

first through fourth wire electrodes disposed on the outer surface of the elongated member, wherein the electrodes are electrically arranged in a series configuration and are also arranged coplanar with one another;

a non-conductive gap electrode between any two adjacent wires, characterized by:

a first wire extending over the outer surface of the elongated member connecting a first wire electrode to a first electrical output terminal of a high voltage power supply;

a second wire extending over the outer surface of the elongated member connecting a second terminal electrode to a second electrical output terminal of a high voltage power supply;

a third wire extending over the outer surface of the elongated member connecting a third terminal electrode to a third electrical output terminal of a high voltage power supply; and is

A fourth wire extending over the outer surface of the elongated member connects a fourth terminal electrode to a fourth electrical output terminal of a high voltage power supply.

7. The device of claim 5, further comprising first through fourth physically isolated electrodes, wherein:

a first physically isolated electrode disposed within the non-conductive gap between the first and second wire electrodes disposed adjacent to each other;

a second physically isolated electrode is disposed within the non-conductive gap between the second and third lead electrodes disposed adjacent to each other;

a third physically isolated electrode is disposed within the non-conductive gap between the third and fourth wire electrodes that are disposed adjacent to each other.