US-12622717-B2 - Intravascular lithotripsy catheter with interfering shock waves

Abstract

The present invention provides a catheter for treating an occlusion in a body lumen. The catheter includes an elongated tube, a first electrode pair and a second electrode pair each configured to generate shock waves. The catheter also includes a flexible polymer enclosure that is fillable with conductive fluid and wrapped circumferentially around at least a portion of the elongated tube such that it surrounds the first and second electrode pairs. The first and second electrode pairs can be arranged relative to one another to promote interference between shock waves generated at the electrode pairs when voltage is delivered across the electrodes of each pair. Electrode pairs can be longitudinally adjacent (spaced a relatively small longitudinal distance apart), longitudinally aligned (at the same longitudinal location), circumferentially offset (offset about the circumference of the catheter), circumferentially aligned (at the same circumferential location), or any combination of any of the above.

Inventors

• Khanh Vo

Assignees

• SHOCKWAVE MEDICAL, INC.

Dates

Publication Date

20260512

Application Date

20240510

Claims (20)

1. 1 . A method for treating an occlusion in a body lumen, the method comprising: advancing a catheter comprising a guidewire lumen over a guidewire within a body lumen to a target treatment site; and generating shock waves using a first electrode pair at a first location of the catheter and a second electrode pair at a second location of the catheter such that the shock waves constructively interfere to produce a combined shock wave to treat an occlusion at the target treatment site.
2. 2 . The method of claim 1 , wherein the first and second locations are longitudinally spaced apart in a longitudinal direction of the catheter.
3. 3 . The method of claim 2 , wherein the first and second locations are spaced apart by 1 mm to 4 mm.
4. 4 . The method of claim 3 , wherein the first and second locations are circumferentially aligned with respect to a longitudinal axis of the catheter.
5. 5 . The method of claim 1 , wherein the first location is circumferentially offset from the second location with respect to a longitudinal axis of the catheter.
6. 6 . The method of claim 5 , wherein the first and second locations are offset by an angle of less than 180 degrees.
7. 7 . The method of claim 5 , wherein the first and second locations are longitudinally aligned with respect to the longitudinal axis of the catheter.
8. 8 . The method of claim 1 , wherein a sheath forms an electrode of the first electrode pair.
9. 9 . The method of claim 1 , wherein a first sheath forms an electrode of the first electrode pair and a second sheath forms an electrode of the second electrode pair.
10. 10 . The method of claim 9 , wherein the first sheath forms an electrode of a third electrode pair that is at the same longitudinal location as the first electrode pair.
11. 11 . The method of claim 10 , wherein the first electrode pair and the third electrode pair are circumferentially offset by an angle of 60 to 180 degrees.
12. 12 . The method of claim 9 , wherein the second sheath forms an electrode of a fourth electrode pair.
13. 13 . The method of claim 1 , comprising generating shock waves at third and fourth locations of the catheter such that the shock waves from the third and fourth locations constructively interfere to produce a combined shock wave that is different than the combined shock wave produced by the shock waves generated at the first and second locations.
14. 14 . The method of claim 13 , wherein the shock waves generated at the third and fourth locations are generated independently of the shock waves generated at the first and second locations.
15. 15 . The method of claim 14 , wherein the shock waves generated at the third and fourth locations do not constructively interfere with the shock waves generated at the first and second locations.
16. 16 . The method of claim 13 , wherein the shock waves generated at the third and fourth locations are generated simultaneously with or up to a few nanoseconds apart from the shock waves generated at the first and second locations.
17. 17 . The method of claim 13 , wherein the third and fourth locations are circumferentially offset from the first and second locations.
18. 18 . The method of claim 13 , wherein the third and fourth locations are longitudinally spaced from the first and second locations in a longitudinal direction of the catheter.
19. 19 . The method of claim 1 , wherein the combined shock wave propagates radially outwardly relative to a longitudinal axis of the catheter.
20. 20 . The method of claim 1 , wherein the combined shock wave is produced within a flexible enclosure.

Description

CROSS REFERENCE TO RELATED APPLICATIONS This is a continuation application of U.S. patent application Ser. No. 18/236,631, filed Aug. 22, 2023, which is a divisional application of U.S. patent application Ser. No. 17/967,544, filed on Oct. 17, 2022, now U.S. Pat. No. 11,779,363, issued Oct. 10, 2023, which claims the benefit of U.S. Provisional Application No. 63/257,397, filed on Oct. 19, 2021, the entire contents of each of which are incorporated herein by reference. FIELD OF THE DISCLOSURE The present disclosure relates generally to the field of medical devices and 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 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. More recently, catheters have been developed that include pairs of electrodes for generating shock waves inside an angioplasty balloon. Shock wave devices can be particularly effective for treating calcified 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 the calcified 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. Voltage can then be applied to 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 vessel. Efforts have been made to improve the delivery of shock waves in these devices, for instance, by directing shock waves in a forward direction to break up tighter and harder-to-cross occlusions in vasculature. Examples of forward-firing designs can be found in U.S. Pat. No. 10,966,737 and U.S. Publication Nos. 2019/0388110, both of which are incorporated herein by reference. Other catheter devices have been designed to include arrays of low-profile electrode assemblies that reduce the crossing profile of the catheter and allow the catheter to more easily navigate calcified vessels to deliver shock waves in more severely occluded regions of vasculature. For instance, U.S. Pat. Nos. 8,888,788, and 10,709,462, both of which are incorporated herein by reference, provide examples of low-profile electrode assemblies. Despite these advances, many currently available shock wave catheters have challenges producing shock waves with sufficient acoustic pressure to treat dense and hard-to-crack calcium, or eccentric calcium, in large arterial vessels. First, the total lesion-cracking energy delivered by shock wave catheters is limited by the voltage source used to induce shock wave formation. While many conventional shock wave catheter devices use high voltage pulse generators, these generators deliver only a limited range of voltages, and extremely high voltages can risk rupturing the catheter balloon and damaging a patient's vasculature during shock wave treatments. Second, many shock wave catheter designs distribute energy to an electrode assembly with more than one pair of electrodes connected in series and spaced out along the catheter at a distance of six millimeters (6 mm) or more apart. When spacing electrode pairs more than 6 mm apart from one another, the acoustic shock waves generated by each of the electrode pairs may propagate individually with minimal overlap to adjacent waves, resulting in the delivery of lower pressure single-wavefront shock waves. Additionally, when connecting multiple electrode pairs in series on the same voltage channel, the voltage is evenly distributed among the electrodes, which reduces the peak pressure of shock waves generated at each electrode pair thereby producing an array of shock waves having a relatively lower peak pressure. Third, some current shock wave catheter designs include emitters that each include a pair of electrode pairs that are