Balloon assembly for valvuloplasty catheter system

1. A catheter system for treating a treatment site within or adjacent to a heart valve within a body of a patient, the catheter system comprising:

an energy source that generates energy;

an energy guide that is configured to receive energy from the energy source; and

a balloon assembly that is positionable adjacent to the treatment site, the balloon assembly including an outer balloon and an inner balloon that is positioned substantially within the outer balloon, each of the balloons having a balloon wall that defines a balloon interior, each of the balloons being configured to retain a balloon fluid within the balloon interior, the balloon wall of the inner balloon being positioned spaced apart from the balloon wall of the outer balloon to define an interstitial space therebetween;

wherein a portion of the energy guide is positioned within the interstitial space between the balloons to generate plasma-induced bubble formation in the balloon fluid within the interstitial space upon the energy guide receiving energy from the energy source.

2. The catheter system of claim 1 wherein the energy guide includes a guide distal end that is positioned within the interstitial space between the balloons so that a plasma-induced bubble is formed in the balloon fluid within the interstitial space.

3. The catheter system of claim 1 wherein each of the balloons is selectively inflatable with the balloon fluid to expand to an inflated state, and wherein when the balloons are in the inflated state the balloon wall of the inner balloon is spaced apart from the balloon wall of the outer balloon to define the interstitial space therebetween.

4. The catheter system of claim 3 wherein when the balloons are in the inflated state, the outer balloon is configured to be positioned substantially adjacent to the treatment site.

5. The catheter system of claim 3 wherein when the balloons are in the inflated state, the inner balloon has an inner balloon diameter, and the outer balloon has an outer balloon diameter that is greater than the inner balloon diameter of the inner balloon.

6. The catheter system of claim 5 wherein when the balloons are in the inflated state, the outer balloon diameter of the outer balloon is at least approximately 5% greater than the inner balloon diameter of the inner balloon.

7. The catheter system of claim 5 wherein when the balloons are in the inflated state, the outer balloon diameter of the outer balloon is at least approximately 10% greater than the inner balloon diameter of the inner balloon.

8. The catheter system of claim 5 wherein when the balloons are in the inflated state, the outer balloon diameter of the outer balloon is at least approximately 20% greater than the inner balloon diameter of the inner balloon.

9. The catheter system of claim 5 wherein when the balloons are in the inflated state, the outer balloon diameter of the outer balloon is at least approximately 30% greater than the inner balloon diameter of the inner balloon.

10. The catheter system of claim 3 wherein when the balloons are in the inflated state, the inner balloon is inflated to a greater inflation pressure than the outer balloon.

11. The catheter system of claim 3 wherein when the balloons are in the inflated state, the inner balloon has a first balloon shape and the outer balloon has a second balloon shape that is different from the first balloon shape.

12. The catheter system of claim 1 wherein the inner balloon is made from a first material, and wherein the outer balloon is made from a second material that is different from the first material.

13. The catheter system of claim 12 wherein the first material has a first compliance, and wherein the second material has a second compliance that is greater than the first compliance so that the outer balloon expands at a faster rate than the inner balloon when the balloons are expanded to an inflated state.

14. The catheter system of claim 12 wherein the first material is non-compliant, and wherein the second material is semi-compliant.

15. The catheter system of claim 12 wherein the first material is non-compliant, and wherein the second material is compliant.

16. The catheter system of claim 12 wherein the first material is semi-compliant, and wherein the second material is compliant.

17. The catheter system of claim 1 wherein the energy guide is positioned substantially directly adjacent to an outer surface of the inner balloon.

18. The catheter system of claim 17 wherein the energy guide is adhered to the outer surface of the inner balloon.

19. The catheter system of claim 1 wherein the energy guide is positioned spaced apart from the outer surface of the inner balloon.

20. The catheter system of claim 19 further comprising a guide support structure that is mounted on the outer surface of the inner balloon, and wherein the energy guide is positioned on the guide support structure so that the energy guide is positioned spaced apart from the outer surface of the inner balloon.

21. The catheter system of claim 1 wherein the heart valve includes a valve wall; and wherein the balloon assembly is positioned adjacent to the valve wall.

22. The catheter system of claim 1 wherein the heart valve includes a plurality of leaflets; and wherein the balloon assembly is positioned adjacent to at least one of the plurality of leaflets.

23. The catheter system of claim 1 further comprising a plasma generator that is positioned near a guide distal end of the energy guide, the plasma generator being configured to generate the plasma-induced bubble in the balloon fluid within the interstitial space between the balloons.

24. The catheter system of claim 23 wherein the guide distal end of the energy guide is positioned within the interstitial space between the balloons approximately at a midpoint of the heart valve.

25. The catheter system of claim 1 wherein the formation of the plasma-induced bubble imparts pressure waves upon the balloon wall of the outer balloon adjacent to the treatment site.

26. The catheter system of claim 1 wherein the energy source generates pulses of energy that are guided along the energy guide into the interstitial space between the balloons to induce the plasma-induced bubble formation in the balloon fluid within the interstitial space between the balloons.

27. The catheter system of claim 1 wherein the energy source is a laser source that provides pulses of laser energy.

28. The catheter system of claim 1 wherein the energy guide includes an optical fiber.

29. The catheter system of claim 1 wherein the energy source is a high voltage energy source that provides pulses of high voltage.

30. The catheter system of claim 1 wherein the energy guide includes an electrode pair including spaced apart electrodes that extend into the interstitial space between the balloons; and wherein pulses of high voltage from the energy source are applied to the electrodes and form an electrical arc across the electrodes.