Method and system for reducing arterial restenosis in the presence of an intravascular stent

• US 20030187340A1
• Filed: 03/26/2003
• Published: 10/02/2003
• Est. Priority Date: 04/19/1999
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: KenKnight, Bruce H., Warren, Jay A., Hahn, Stephen John
• Granted Patent: US 6,939,345 B2
• Time in Patent Office: Days
• US Class Current: 600/372
• CPC Class Codes: A61B 18/1492 having a flexible, catheter-like structure, e.g. for heart ablation A61B18/1477 takes precedence
• CPC Class Codes: A61B 2018/00214 Expandable means emitting energy, e.g. by elements carried thereon
• CPC Class Codes: A61B 2018/0022 Balloons
• CPC Class Codes: A61B 2018/00285 Balloons
• CPC Class Codes: A61B 2018/00839 Bioelectrical parameters, e.g. ECG, EEG

Abstract

A first electrode is positioned within an artery proximate an implanted intravascular stent. A second electrode is positioned at a separate location relative the position of the first electrode. Electrical energy is then delivered between the first and the second electrodes to produce an electrical field adjacent the implanted intravascular stent. When a intravascular stent is implanted in a coronary artery, the delivery of the electrical energy is coordinated to cardiac cycles detected in sensed cardiac signals, where the delivery of the electrical energy between the first electrode and the second electrode occurs during a predetermined portion of the cardiac cycle.

Claims

1. A method comprising:

positioning a first electrode near an implanted intravascular stent;

positioning a second electrode at a different position from the first electrode; and

delivering at least one pulse of electrical energy between the first and second electrodes at a repetition rate that is less than or equal to the order of a frequency between heart depolarizations.

2. The method of claim 1, wherein the positioning the second electrode includes positioning the second electrode at a remote position outside a lumen of the stent.

3. The method of claim 2, wherein the positioning the second electrode includes positioning the second electrode external to a patient.

4. The method of claim 3, wherein the positioning the second electrode includes positioning the second electrode on a dermal surface.

5. The method of claim 1, wherein the positioning the first electrode includes positioning the first electrode within a blood vessel.

6. The method of claim 5, wherein the positioning the first electrode includes positioning at least a portion of the first electrode within a lumen of stent.

7. The method of claim 5, wherein the positioning the first electrode includes positioning the first electrode within a lumen of the stent such that first and second electrode ends substantially align with respective first and second stent ends.

8. The method of claim 1, wherein positioning the first electrode includes positioning the first electrode on a catheter, and wherein the positioning the second electrode includes positioning the second electrode on the same catheter.

9. The method of claim 1, wherein at least one of the positioning the first electrode and the positioning the second electrode includes contacting one of the first and second electrodes with the stent.

10. The method of claim 1, further including sensing a cardiac signal, and wherein the delivering at least one pulse includes delivering the at least one pulse during a predetermined portion of a cardiac cycle.

11. The method of claim 1, in which the delivering at least one pulse includes discharging a capacitor.

12. The method of claim 1, in which the delivering at least one pulse includes delivering at least one substantially constant current pulse.

13. The method of claim 1, in which the delivering at least one pulse includes delivering at least one substantially direct current (DC) pulse.

14. The method of claim 1, in which the delivering at least one pulse includes delivering at least one pulse having a current density between about 1 ampere/cm² and about 4 amperes/cm².

15. The method of claim 1, in which the positioning the first electrode includes contacting the first electrode with the stent.

16. A method comprising:

positioning a first electrode near an implanted intravascular stent;

positioning a second electrode at a different position from the first electrode; and

delivering sub-radio-frequency electrical energy between the first electrode and the second electrode.

17. The method of claim 16, wherein the positioning the second electrode includes positioning the second electrode at a remote position outside a lumen of the stent.

18. The method of claim 17, wherein the positioning the second electrode includes positioning the second electrode external to a patient.

19. The method of claim 18, wherein the positioning the second electrode includes positioning the second electrode on a dermal surface.

20. The method of claim 16, wherein the positioning the first electrode includes positioning the first electrode within a blood vessel.

21. The method of claim 20, wherein the positioning the first electrode includes positioning at least a portion of the first electrode within a lumen of stent.

22. The method of claim 20, wherein the positioning the first electrode includes positioning the first electrode within a lumen of the stent such that first and second electrode ends substantially align with respective first and second stent ends.

23. The method of claim 16, wherein positioning the first electrode includes positioning the first electrode on a catheter, and wherein the positioning the second electrode includes positioning the second electrode on the same catheter.

24. The method of claim 16, wherein at least one of the positioning the first electrode and the positioning the second electrode includes contacting one of the first and second electrodes with the stent.

25. The method of claim 16, further including sensing a cardiac signal, and wherein the delivering at least one pulse includes delivering the at least one pulse during a predetermined portion of a cardiac cycle.

26. The method of claim 16, in which the delivering at least one pulse includes discharging a capacitor.

27. The method of claim 16, in which the delivering at least one pulse includes delivering at least one substantially constant current pulse.

28. The method of claim 16, in which the delivering at least one pulse includes delivering at least one substantially direct current (DC) pulse.

29. The method of claim 16, in which the delivering at least one pulse includes delivering at least one pulse having a current density between about 1 ampere/cm² and about 4 amperes/cm².

30. The method of claim 16, in which the positioning the first electrode includes contacting the first electrode with the stent.

31. A method comprising:

positioning a first electrode near an implanted intravascular stent;

positioning a second electrode at a different position from the first electrode;

measuring an impedance between the first and second electrodes; and

delivering electrical energy between the first and second electrodes, including determining at least one parameter of the electrical energy using the measured impedance between the first and second electrodes.

32. The method of claim 31, wherein the positioning the second electrode includes positioning the second electrode at a remote position outside a lumen of the stent.

33. The method of claim 32, wherein the positioning the second electrode includes positioning the second electrode external to a patient.

34. The method of claim 33, wherein the positioning the second electrode includes positioning the second electrode on a dermal surface.

35. The method of claim 31, wherein the positioning the first electrode includes positioning the first electrode within a blood vessel.

36. The method of claim 35, wherein the positioning the first electrode includes positioning at least a portion of the first electrode within a lumen of stent.

37. The method of claim 35, wherein the positioning the first electrode includes positioning the first electrode within a lumen of the stent such that first and second electrode ends substantially align with respective first and second stent ends.

38. The method of claim 31, wherein positioning the first electrode includes positioning the first electrode on a catheter, and wherein the positioning the second electrode includes positioning the second electrode on the same catheter.

39. The method of claim 31, wherein at least one of the positioning the first electrode and the positioning the second electrode includes contacting one of the first and second electrodes with the stent.

40. The method of claim 31, further including sensing a cardiac signal, and wherein the delivering at least one pulse includes delivering the at least one pulse during a predetermined portion of a cardiac cycle.

41. The method of claim 31, in which the delivering at least one pulse includes discharging a capacitor.

42. The method of claim 31, in which the delivering at least one pulse includes delivering at least one substantially constant current pulse.

43. The method of claim 31, in which the delivering at least one pulse includes delivering at least one substantially direct current (DC) pulse.

44. The method of claim 31, in which the delivering at least one pulse includes delivering at least one pulse having a current density between about 1 ampere/cm² and about 4 amperes/cm².

45. The method of claim 31, in which the measuring the impedance includes:

delivering a test current between the first and second; and

measuring a resulting voltage between the first and second electrodes, the resulting voltage resulting from the delivering the test current.

46. The method of claim 31, in which the determining at least one parameter of the electrical energy includes determining a voltage amplitude of the electrical energy.

47. The method of claim 46, in which the determining the voltage amplitude of the electrical energy includes calculating the voltage amplitude using the measured impedance and a predetermined critical current density value.

48. The method of claim 47, in which the calculating the voltage amplitude includes multiplying the predetermined critical current density value by a surface area of at least one of the first and second electrodes.

49. The method of claim 31, in which the positioning the first electrode includes contacting the first electrode with the stent.

50. A system comprising:

a first electrode, sized and shaped to permit intravascular positioning near an intravascular stent; and

an energy discharge control circuit, configured to be operatively coupled to the first electrode, the energy discharge control circuit capable of delivering sub-radio-frequency electrical energy near the stent using the first electrode.

51. The system of claim 50, further comprising a second electrode, and wherein the energy discharge control circuit is configured to be coupled to the second electrode, the energy discharge control circuit capable of delivering the sub-radio-frequency energy near the stent using the first and second electrodes.

52. The system of claim 50, further comprising the intravascular stent.

53. The system of claim 50, in which the energy discharge control circuit includes an energy discharge capacitor.

54. The system of claim 50, further comprising an electrogram analysis circuit coupled to and providing a triggering signal to the energy discharge control circuit.

55. The system of claim 50, further comprising a programmer, the programmer including a user interface, the programmer operatively coupled to the energy discharge control circuit to provide at least one parameter controlling the energy discharge control circuit.

56. The system of claim 50, further including an intravascular catheter that includes the first electrode.

57. The system of claim 50, further including an external lead that includes a second electrode.

58. A system comprising:

a first electrode, sized and shaped to permit intravascular positioning near an intravascular stent;

a second electrode; and

an energy discharge control circuit, configured to be operatively coupled to the first and second electrodes, the energy discharge control circuit including an impedance measurement circuit coupled to the first and second electrodes to measure an impedance between the first and second electrodes, the energy discharge control circuit capable of delivering electrical energy near the stent using the first and second electrodes, wherein at least one parameter of the electrical energy is based on the measured impedance between the first and second electrodes.

59. The system of claim 58, further comprising a second electrode, and wherein the energy discharge control circuit is configured to be coupled to the second electrode, the energy discharge control circuit capable of delivering the sub-radio-frequency energy near the stent using the first and second electrodes.

60. The system of claim 58, further comprising the intravascular stent.

61. The system of claim 58, in which the energy discharge control circuit includes an energy discharge capacitor.

62. The system of claim 58, further comprising an electrogram analysis circuit coupled to and providing a triggering signal to the energy discharge control circuit.

63. The system of claim 58, further comprising a programmer, the programmer including a user interface, the programmer operatively coupled to the energy discharge control circuit to provide at least one parameter controlling the energy discharge control circuit.

64. The system of claim 58, further including an intravascular catheter that includes the first electrode.

65. The system of claim 58, further including an external lead that includes the second electrode.