EP-4734859-A1 - CATHETER SYSTEM WITH INDEPENDENTLY CONTROLLABLE BUBBLE AND ARC GENERATION

Abstract

Described herein are systems and methods for implementing a power source for a shock wave catheter system, the power source including two separate voltage sources: a bubble generation voltage source and an arc generation voltage source. In one or more examples, the power source can be configured such that the bubble generation voltage source provides a lower voltage to a pair of electrodes of the shock wave catheter system. The lower voltage can be configured to induce electrolysis of a fluid that surrounds the pair of electrodes of the shock wave catheter system for generating and growing a bubble. Once a bubble has formed, the arc generation voltage source can then be engaged to provide a high-voltage electrical pulse to the electrodes of the shock wave catheter system, thereby generating an arc (i.e., spark) across the electrodes.

Inventors

• ULLMANN, JENS

Assignees

• Shockwave Medical, Inc.

Dates

Publication Date

20260506

Application Date

20230804

Claims (20)

1. 1. A method for generating a shock wave in a shock wave catheter system, the method comprising: applying a first voltage, using a first voltage source, to one or more electrodes of the shock wave catheter system to prime an aqueous environment or generate one or more bubbles in a fluid surrounding the one or more electrodes; and applying a second voltage, using a second voltage source, to the one or more electrodes to generate an electrical arc at the one or more electrodes, wherein the first voltage source and the second voltage source are independently controllable.
2. 2. The method of claim 1, further comprising: selectively electrically coupling or decoupling the first voltage source or the second voltage source with the one or more electrodes.
3. 3. The method of claim 1, further comprising: electrically separating the first voltage source from the second voltage source.
4. 4. The method of claim 3, wherein the electrically separating comprises restricting current flow between the first voltage source and the second voltage source.
5. 5. The method of claim 1, further comprising: receiving an external input corresponding to a user operating a button; and generating one or more signals to control a first switch or a second switch of the shock wave catheter system based on the external input.
6. 6. The method of claim 1, further comprising: operating the shock wave catheter system in a bubble generation mode, comprising: closing a first switch to electrically couple the first voltage source with the one or more electrodes; and opening a second switch to electrically decouple the second voltage source from the one or more electrodes.
7. 7. The method of claim 1, further comprising: operating the shock wave catheter system in an arc generation mode, comprising: closing a second switch to electrically couple the second voltage source with the one or more electrodes.
8. 8. The method of claim 1, further comprising: determining whether a bubble has been formed at the one or more electrodes; and in accordance with the bubble having been formed, operating the shock wave catheter system in an arc generation mode.
9. 9. The method of claim 8, wherein the determining whether a bubble has been formed comprises determining whether the shock wave catheter system has operated in a bubble generation mode for a threshold amount of time.
10. 10. The method of claim 8, wherein the determining whether a bubble has been formed comprises determining whether an amount of current flowing from the first voltage source to the one or more electrodes meets a threshold amount of current.
11. 11. The method of claim 10, wherein the amount of current flowing meeting the threshold amount of current comprises the amount of current flowing being less than 100 pA.
12. 12. The method of claim 1, further comprising: determining whether an amount of current flowing from the second voltage source to the one or more electrodes meets a threshold amount of current; and in accordance with the amount of current flowing meeting the threshold amount of current, terminating operation of the shock wave catheter system in an arc generation mode.
13. 13. The method of claim 12, wherein the amount of current flowing meeting the threshold amount of current comprises the amount of current flowing being greater than 50A.
14. 14. The method of claim 1, further comprising: operating the shock wave catheter system in a bubble generation mode; and operating the shock wave catheter system in an arc generation mode, wherein a period of time for operating in the bubble generation mode is longer than a period of time for operating in the arc generation mode.
15. 15. The method of claim 1, wherein the applied first voltage is less than the applied second voltage.
16. 16. The method of claim 1, wherein the applied first voltage is from 50 to 250 volts.
17. 17. The method of claim 1, wherein the applied second voltage is from 2,000 to 10,000 volts.
18. 18. The method of claim 1, wherein the first voltage is applied across the one or more electrodes of the shock wave catheter system.
19. 19. The method of claim 1, wherein the second voltage is applied across the one or more electrodes of the shock wave catheter system.
20. 20. The method of claim 1, further comprising: applying a third voltage to the one or more electrodes of the shock wave catheter system to cause metal to be deposited on the one or more electrodes.

Description

CATHETER SYSTEM WITH INDEPENDENTLY CONTROLLABLE BUBBLE AND ARC GENERATION CROSS-REFERENCE TO RELATED APPLICATION [0001] This application claims the benefit of U.S. Non-Provisional Application No. 18/216,084, filed June 29, 2023, the entire contents of which are hereby incorporated by reference herein. FIELD OF THE DISCLOSURE [0002] The present disclosure relates generally to medical devices and associated methods, and more specifically, to shock wave catheter devices for treating calcified lesions in body lumens, such as calcified lesions and occlusions in vasculature and kidney stones in the urinary system. BACKGROUND [0003] A wide variety of catheters have been developed for treating calcified lesions, such as calcified lesions in vasculature associated with arterial disease. For example, treatment systems for percutaneous coronary angioplasty or peripheral angioplasty use angioplasty balloons to dilate a calcified lesion and restore normal blood flow in a vessel. In these types of procedures, a catheter carrying a balloon is advanced into the vasculature along a guide wire until the balloon is aligned with calcified plaques. The balloon is then pressurized (normally to greater than 10 atm), causing the balloon to expand in a vessel to push calcified plaques back into the vessel wall and dilate occluded regions of vasculature. [0004] More recently, the technique and treatment of intravascular lithotripsy (IVL) has been developed, which is an interventional procedure to modify calcified plaque in diseased arteries. The mechanism of plaque modification is through use of a catheter having one or more acoustic shock wave generating sources located within a liquid that can generate acoustic shock waves that modify the calcified plaque. IVL devices vary in design with respect to the energy source used to generate the acoustic shock waves, with two exemplary energy sources being electrohydraulic generation and laser generation. [0005] For electrohydraulic generation of acoustic shock waves, a conductive solution (e.g., saline) may be contained within an enclosure that surrounds electrodes or can be flushed through a tube that surrounds the electrodes. The calcified plaque modification is achieved by creating acoustic shock waves within the catheter by an electrical discharge across the electrodes. This discharge creates one or more rapidly expanding vapor bubbles that generate the acoustic shock waves. These shock waves propagate radially outward and modify calcified plaque within the blood vessels, or laser generation of acoustic shock waves, a laser pulse is transmitted into and absorbed by a fluid within the catheter. This absorption process rapidly heats and vaporizes the fluid, thereby generating the rapidly expanding vapor bubble, as well as the acoustic shock waves that propagate outward and modify the calcified plaque. The acoustic shock wave intensity is higher if a fluid is chosen that exhibits strong absorption at the laser wavelength that is employed. These examples of IVL devices are not intended to be a comprehensive list of potential energy sources to create IVL shock waves. [0006] The IVL process may be considered different from standard atherectomy procedures in that it cracks calcium but does not liberate the cracked calcium from the tissue. Hence, generally speaking, IVL should not require aspiration nor embolic protection. Further, due to the compliance of a normal blood vessel and non-calcified plaque, the shock waves produced by IVL do not modify the normal vessel or non-calcified plaque. [0007] More specifically, catheters to deliver IVL therapy have been developed that include pairs of electrodes for electrohydraulically generating shock waves inside an angioplasty balloon. Shock wave devices can be particularly effective for treating calcified plaque lesions because the acoustic pressure from the shock waves can crack and disrupt lesions near the angioplasty balloon without harming the surrounding tissue. In these devices, the catheter is advanced over a guidewire through a patient’s vasculature until it is positioned proximal to and/or aligned with a calcified plaque lesion in a body lumen. The balloon is then inflated with conductive fluid (using a relatively low pressure of 2-4 atm) so that the balloon expands to contact the lesion, but is not an inflation pressure that substantively displaces the lesion. Voltage pulses can then be applied across the electrodes of the electrode pairs to produce acoustic shock waves that propagate through the walls of the angioplasty balloon and into the lesions. Once the lesions have been cracked by the acoustic shock waves, the balloon can be expanded further to increase the cross-sectional area of the lumen and improve blood flow through the lumen. Alternative devices to deliver IVL therapy can be within a closed volume other than an angioplasty balloon, such as a cap, balloons of variable compliancy, or other enclosure. [0008] Efforts have been