Electrode structures and methods for their use in cardiovascular reflex control

• US 20040010303A1
• Filed: 03/27/2003
• Published: 01/15/2004
• Est. Priority Date: 09/26/2001
• Status: Active Grant

• Current Assignee: CVRx, Inc.
• Original Assignee: CVRx, Inc.
• Inventors: Bolea, Stephen L., Keith, Peter T., Serdar, David J., Persson, Bruce J., Rossing, Martin A., Kieval, Robert S., Irwin, Eric D.
• Granted Patent: US 7,499,742 B2
• Time in Patent Office: Days
• US Class Current: 607/118
• CPC Class Codes: A61B 5/02028 Determining haemodynamic parameters not otherwise provided for, e.g. cardiac contractility or left ventricular ejection fraction
• CPC Class Codes: A61N 1/05 for implantation or insertion into the body, e.g. heart electrode A61N1/06 takes precedence
• CPC Class Codes: A61N 1/0551 Spinal or peripheral nerve electrodes
• CPC Class Codes: A61N 1/056 Transvascular endocardial electrode systems
• CPC Class Codes: A61N 1/36053 adapted for vagal stimulation A61N1/36114 takes precedence
• CPC Class Codes: A61N 1/3611 Respiration control stimulating respiratory organs A61N1/3601
• CPC Class Codes: A61N 1/36114 Cardiac control, e.g. by vagal stimulation stimulating the heart A61N1/362
• CPC Class Codes: A61N 1/36117 for treating hypertension
• CPC Class Codes: A61N 1/36125 Details of circuitry or electric components
• CPC Class Codes: A61N 1/36135 using physiological parameters
• CPC Class Codes: A61N 1/36185 Selection of the electrode configuration
• CPC Class Codes: A61N 1/3702 Physiological parameters A61N1/365 takes precedence; evoked response A61N1/371

Abstract

Devices, systems and methods are described by which the blood pressure, nervous system activity, and neurohormonal activity may be selectively and controllably reduced by activating baroreceptors. A baroreceptor activation device is positioned near a baroreceptor, preferably a baroreceptor located in the carotid sinus. A control system may be used to modulate the baroreceptor activation device. The control system may utilize an algorithm defining a stimulus regimen which promotes long term efficacy and reduces power requirements/consumption. The baroreceptor activation device may utilize electrodes to activate the baroreceptors. The electrodes may be adapted for connection to the carotid arteries at or near the carotid sinus, and may be designed to minimize extraneous tissue stimulation.

Claims

1. A baroreceptor activation device for activating a baroreceptor in a carotid sinus of a patient, the carotid sinus having a circumference, the device comprising:

a base having a length sufficient to extend around at least a substantial portion of the circumference of the carotid sinus, wherein said base is sufficiently elastic to conform to said circumference; and

one or more electrodes connected to the base, the electrodes having a length which is at least partly in the circumferential direction and which is sufficiently stretchable to conform to the carotid sinus with the base.

2. A baroreceptor activation device as in claim 1, comprising two or more electrodes positioned circumferentially and adjacent each other on the base.

3. A baroreceptor activation device as in claim 1, wherein the electrodes extend less than 75% of the length of the base.

4. A baroreceptor activation device as in claim 1, wherein the electrodes extend less than 50% of the length of the base.

5. A baroreceptor activation device as in claim 1, wherein the electrodes extend less than 25% of the length of the base.

6. A baroreceptor activation device as in claim 1, wherein the base has first and second ends, and wherein the ends are adapted to be joined.

7. A baroreceptor activation device as in claim 1, wherein the base has sufficient structural integrity to grasp the carotid sinus.

8. An extravascular electrode assembly comprising:

an elastic base adapted to be conformably attached over the outside of a blood vessel; and

a stretchable electrode secured over a surface of the elastic base.

9. An electrode assembly as in claim 8, wherein the elastic base comprises an elastomeric sheet.

10. An electrode assembly as in claim 9, wherein the elastomeric sheet comprises an elastomer selected from the group consisting of silicone, polyurethane, and latex.

11. An electrode assembly as in claim 8, further comprising two or more attachment tabs attached to the elastomeric sheet at locations which allow at least some of the tabs to overlap the elastic base and/or be directly connected to the vessel wall when the base is wrapped around a blood vessel so that the tabs may be fastened to secure the backing over the blood vessel.

12. An extravascular electrode assembly as in claim 8, wherein the stretchable electrode comprises an elongated coil.

13. An extravascular electrode assembly as in claim 12, wherein individual turns of the coil are flattened in a plane parallel to that of the elastic base.

14. An electrode assembly as in claim 8, comprising two or more stretchable electrodes positioned circumferentially and adjacent each other on the base.

15. An electrode assembly as in claim 8, wherein the electrodes extend less than 75% of the length of the base.

16. An electrode assembly as in claim 8, wherein the electrodes extend less than 50% of the length of the base.

17. An electrode assembly as in claim 8, wherein the electrodes extend less than 25% of the length of the base.

18. An electrode assembly as in claim 8, wherein the base has first and second ends, and wherein the ends are adapted to be joined.

19. An extravascular electrode assembly comprising:

a base adapted to be attached over the outside of a blood vessel, said base having an electrode-carrying surface and a plurality of attachment tabs extending away from the electrode-carrying surface, wherein the tabs are arranged to permit selective ones of the tabs to be wrapped around a blood vessel while others of the tabs are removed; and

an electrode structure on the electrode-carrying surface.

20. An electrode assembly as in claim 19, wherein the base includes at least one tab which extends longitudinally from the electrode-carrying surface and at least two tabs which extend away from the surface at opposite transverse angles.

21. An electrode assembly as in claim 20, wherein the electrode-carrying surface is rectangular, including at least two longitudinally extending tabs extending from adjacent corners of the surface, wherein the two transversely angled tabs extend from the same corners.

22. An electrode assembly as in claim 19, wherein the electrode structure comprises one or more stretchable electrodes secured to the electrode-carrying surface.

23. An electrode assembly as in claim 22, wherein the stretchable electrode comprises an elongated coil.

24. An electrode assembly as in claim 23, wherein individual turns of the coil are flattened in a plane parallel to that of the elastic backing.

25. An electrode assembly as in claim 19, wherein the elastic base comprises an elastomeric sheet.

26. An electrode assembly as in claim 25, wherein the elastomeric sheet comprise an elastomer selected from the group consisting of silicone, polyurethane, and latex.

27. An electrode assembly as in claim 19, comprising two or more electrodes positioned circumferentially and adjacent each other on the base.

28. An electrode assembly as in claim 19, wherein the electrodes extend less than 75% of the length of the base.

29. An electrode assembly as in claim 19, wherein the electrodes extend less than 50% of the length of the base.

30. An electrode assembly as in claim 19, wherein the electrodes extend less than 25% of the length of the base.

31. An electrode assembly as in claim 19, wherein the base has first and second ends, and wherein the ends are adapted to be joined.

32. A method for wrapping an electrode assembly over a blood vessel, said method comprising:

providing an electrode assembly comprising an elastic base and a stretchable electrode secured over a surface of the elastic base;

conforming the base over an exterior of the blood vessel, wherein at least a portion of the electrode assembly can flex and stretch with expansions and contractions of the blood vessel; and

securing ends of the elastic base together and/or to the vessel wall to hold the electrode assembly in place.

33. A method as in claim 32, wherein conforming comprises locating the stretchable electrode over a target site in the blood vessel.

34. A method as in claim 33, wherein the target site comprises electrically activated receptors.

35. A method as in claim 34, wherein the electrically activated receptors comprise baroreceptors.

36. A method as in claim 35, wherein the baroreceptors are in or near the carotid sinus.

37. A method as in claim 32, wherein conforming the base comprises covering a circumferential distance around the blood vessel equal to at least 25% of the circumference of the blood vessel exterior.

38. A method as in claim 37, wherein conforming the base comprises covering a circumferential distance around the blood vessel equal to at least 50% of the circumference of the blood vessel exterior.

39. A method as in claim 37, wherein conforming the base comprises covering a circumferential distance around the blood vessel equal to at least 66% of the circumference of the blood vessel exterior.

40. A method as in claim 37, wherein conforming the base comprises covering a circumferential distance around the blood vessel equal to at least 75% of the circumference of the blood vessel exterior.

41. A method as in claim 37, wherein the base is conformed over the entire circumference of the blood vessel exterior.

42. A method for wrapping an electrode assembly over a blood vessel, said method comprising:

providing an electrode assembly comprising a base having an electrode-carrying surface and a plurality of attachment tabs extending away from the electrode-carrying surface, and an electrode structure on the electrode-carrying surface;

wrapping the base over a blood vessel so that the electrode structure is located over a target site; and

securing some but not all tabs together and/or to the vessel wall to hold the electrode assembly in place over the target site.

43. A method as in claim 42, further comprising removing the tabs which are not secured from the electrode-carrying surface.

44. A method as in claim 42, wherein the target site comprises electrically activated receptors.

45. A method as in claim 44, wherein the electrically activated receptor comprises baroreceptors.

46. A method as in claim 45, wherein the baroreceptors are in or near the carotid sinus.

47. A method as in claim 42, wherein conforming the base comprises covering a circumferential distance around the blood vessel equal to at least 25% of the circumference of the blood vessel exterior.

48. A method as in claim 42, wherein conforming the base comprises covering a circumferential distance around the blood vessel equal to at least 50% of the circumference of the blood vessel exterior.

49. A method as in claim 42, wherein conforming the base comprises covering a circumferential distance around the blood vessel equal to at least 66% of the circumference of the blood vessel exterior.

50. A method as in claim 42, wherein conforming the base comprises covering a circumferential distance around the blood vessel equal to at least 75% of the circumference of the blood vessel exterior.

51. A method as in claim 42, wherein the base is conformed over the entire circumference of the blood vessel exterior.

52. An implantable vascular pressure measuring assembly comprising:

an elastic base adapted to be mounted on the outer wall of a blood vessel under circumferential tension; and

a strain measurement sensor on the elastic base so that changes in circumferential stress may be detected;

wherein the changes in circumferential stress may be correlated to changes in pressure in the blood vessel.

53. An implantable assembly as in claim 52, wherein the elastic base is adapted to be wrapped around the entire circumference of the blood vessel.

54. An implantable assembly as in claim 52, wherein the sensor is a strain gauge or a micro machined sensor.

55. An electrode assembly comprising:

a base attachable to an outside surface of a blood vessel; and

at least three parallel elongate electrode structures secured over a surface of the base, wherein an outer pair of the electrode structures is electrically isolated from an inner electrode structure, whereby the outer pair of electrode structures and the inner electrode structure may be connected to separate poles on a power supply.

56. An electrode assembly as in claim 55, wherein the base has a length sufficient to extend around at least a substantial portion of the circumference of a blood vessel.

57. An electrode assembly as in claim 56, wherein the base has a length sufficient to extend around the entire circumference.

58. An electrode assembly as in claim 55, wherein the base is elastic.

59. An electrode assembly as in claim 58, wherein the electrode structures are stretchable.

60. An electrode assembly as in claim 59, wherein the electrode structures are aligned with the circumferential direction of the base.

61. An electrode assembly as in claim 58, wherein the electrode structures of the outer pair are joined in a U-pattern surrounding the inner electrode structure.

62. An electrode assembly as in claim 59, wherein the electrode structures comprise elongate coils.

63. An electrode assembly as in claim 62, wherein the elongate coils have flattened cross-sections.

64. An electrode assembly as in claim 63, wherein individual turns of the coil are flattened in a plane parallel to that of the base.

65. A baroreceptor activation device as in claim 55, wherein the electrodes extend less than 75% of the length of the base.

66. A baroreceptor activation device as in claim 65, wherein the electrodes extend less than 50% of the length of the base.

67. A baroreceptor activation device as in claim 66, wherein the electrodes extend less than 25% of the length of the base.