Intravascular lithotripsy
A medical device may include an elongated body, a balloon positioned at a distal portion of the elongated body, and one or more pressure-wave emitters positioned along a central longitudinal axis of the elongated body within the balloon. The one or more pressure-wave emitters may be configured to propagate pressure waves radially outward through the fluid to fragment a calcified lesion at the target treatment site. The at least one of the one or more pressure-wave emitters may include an electronic emitter comprising a first electrode and a second electrode. The first electrode and the second electrode may be arranged to define a spark gap between the first electrode and the second electrode, and the second electrode may comprise a portion of a hypotube.
1. A method of forming an electronic pressure-wave emitter of an intravascular lithotripsy (IVL) catheter, the method comprising:
laser-cutting a hypotube to define at least a first electrode and a second electrode arranged to define a spark gap therebetween;
inserting an elongated body through the laser-cut hypotube;
extending an electrode selected from the group consisting of the first electrode, the second electrode, and combinations thereof at least partially radially inward through an outer surface of the elongated body; and
flowing a potting material around the laser-cut hypotube.
2. The method of claim 1 ,
wherein the spark gap comprises a first spark gap; and
wherein laser-cutting the hypotube further comprises laser-cutting the hypotube to define a third electrode arranged so as to define a second spark gap between the second electrode and the third electrode.
3. The method of claim 2 , wherein the first electrode, the second electrode, and the third electrode all define portions of a common cylindrical surface of the hypotube.
4. The method of claim 3 , wherein laser-cutting the hypotube comprises laser-cutting the hypotube such that the first electrode and the third electrode both define rounded triangular shapes, and such that the second electrode defines a parallelogram shape.
5. The method of claim 3 , wherein laser-cutting the hypotube comprises laser-cutting the hypotube such that the first electrode, the second electrode, and the third electrode all define rounded rectangular shapes.
6. The method of claim 3 , wherein laser-cutting the hypotube comprises laser-cutting the hypotube such that the first electrode and the third electrode both define oval shapes, and such that the second electrode defines a semi-cylindrical shape.
7. The method of claim 1 ,
wherein the first electrode is ring-shaped, the second electrode is disc-shaped, and the first electrode at least partially surrounds the second electrode.
8. The method of claim 7 ,
wherein the spark gap comprises a first spark gap,
wherein the laser-cutting the hypotube further comprises laser-cutting the hypotube to define a third electrode and a fourth electrode arranged so as to define a second spark gap between the third electrode and the fourth electrode, and
wherein the third electrode is ring-shaped, the fourth electrode is disc-shaped, and the third electrode at least partially surrounds the fourth electrode.
9. The method of claim 1 , wherein the hypotube defines a longitudinal length from about 0.080 inches to about 0.090 inches.
10. The method of claim 1 , wherein the hypotube defines an outer circumference from about 0.10 inches to about 0.12 inches.
11. The method of claim 1 , wherein the first electrode is rectangular-prism shaped.
12. The method of claim 1 , wherein extending an electrode selected from the group consisting of the first electrode, the second electrode, and combinations thereof at least partially radially inward through an outer surface of the elongated body comprises extending the first electrode at least partially radially inward through an outer surface of the elongated body, the method further comprising extending the first electrode radially inward through the elongated body and at least partially radially inward into an inner lumen of the elongated body.
13. The method of claim 12 , further comprising extending the second electrode at least partially radially inward through the elongated body.
14. The method of claim 13 , further comprising extending the second electrode at least partially radially inward into an inner lumen of the elongated body.
15. The method of claim 1 , further comprising removing obsolete support structures from the hypotube.
16. The method of claim 15 , wherein the potting material is an adhesive.
17. The method of claim 16 , wherein removing obsolete support structures from the hypotube comprises milling out the adhesive.
18. The method of claim 17 , wherein milling out the adhesive comprises re-establishing the spark gap between the first electrode and the second electrode.
19. The method of claim 16 , wherein flowing the potting material around the laser-cut hypotube comprises overflowing adhesive around the laser-cut hypotube.
20. The method of claim 1 , wherein the elongated body comprises a proximal end and a distal end opposite the proximal end, and
wherein the elongated body is configured to deliver fluid to the distal end.