Apparatus and Method for Treatment of In-Stent Restenosis

• US 20130282084A1
• Filed: 10/04/2012
• Published: 10/24/2013
• Est. Priority Date: 09/10/2004
• Status: Active Grant

• Current Assignee: Boston Scientific Scimed (Boston Scientific Corporation)
• Original Assignee: Vessix Vascular, Inc. (Boston Scientific Corporation)
• Inventors: Mathur, Prabodh, Mazor, Meital, Perez, Dolores
• Granted Patent: US 9,713,730 B2
• Time in Patent Office: Days
• US Class Current: 607/101
• 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 2018/00267 having a basket shaped structure
• CPC Class Codes: A61B 2018/00404 Blood vessels other than those in or around the heart
• CPC Class Codes: A61B 2018/00779 Power or energy
• CPC Class Codes: A61B 2018/00791 Temperature
• CPC Class Codes: A61B 2018/00827 Current
• CPC Class Codes: A61B 2018/00875 Resistance or impedance
• CPC Class Codes: A61B 2018/00892 Voltage
• CPC Class Codes: A61B 2018/124 switching the output to different electrodes, e.g. sequentially
• CPC Class Codes: A61B 2018/1467 using more than two electrodes on a single probe
• CPC Class Codes: A61N 2005/0602 for treatment of blood vessels
• CPC Class Codes: A61N 5/00 Radiation therapy ultrasound therapy A61N7/00; devices or apparatus applicable to both therapy and diagnosis A61B6/00
• CPC Class Codes: A61N 5/0601 Apparatus for use inside the body

Abstract

A catheter and catheter system can use energy tailored for remodeling and/or removal of target material proximate to a body lumen, often of stenotic material or tissue in the luminal wall of a blood vessel of a patient. An elongate flexible catheter body with a radially expandable structure may have a plurality of electrodes or other electrosurgical energy delivery surfaces to radially engage the luminal wall when the structure expands. Feedback using one or parameters of voltage, current, power, temperature, impedance magnitude, impedance phase angle, and frequency may be used to selectively control the delivery of energy.

Claims

1. A method for delivering energy-based treatment for in-stent restenosis and other stenosis of the vasculature, the method comprising:

positioning, at a location in the vasculature, a radially expandable structure of an elongate flexible catheter body having a proximal end and a distal end with an axis therebetween, the radially expandable structure being near the distal end of the catheter body;

expanding the radially expandable structure such that a plurality of electrodes positioned on the radially expandable structure engage tissue, and such that an electrical circuit is defined, the electrical circuit including a power source, one of the electrodes, and the engaged tissue within a treatment zone; and

energizing the at least one circuit using the power source a power source, one of the electrodes, and the engaged tissue within a treatment zone; and

,

controlling the delivery of energy using a processor coupled with the power source verifying the presence of the electrical circuit, selectively energizing electrodes, and regulating one or more parameters of the electrical circuit based on monitoring feedback from the electrical circuit such that energy delivered to the treatment zone heats tissue therein to a temperature of about 55°

C. to about 75°

C. while tissue collateral to the treatment zone is heated to less than about 45°

C., thereby inducing a tissue response that remodels stenosis and avoids a subsequently occluding tissue response caused by thermal damage.

2. The method of claim 1, wherein the plurality of electrodes are distributed about the circumference of the expanding structure so as to form an electrode array, the electrodes having an elongate shape oriented to be substantially parallel to the catheter axis upon expansion of the expandable structure.

3. The method of claim 1, wherein the expandable structure comprises a balloon.

4. The method of claim 3, wherein the electrodes positioned on the balloon are included in one or more flex circuit, each flex circuit including a monopolar electrode or a bipolar electrode pair.

5. The method of claim 1, wherein the electrodes include a radiopaque material.

6. The method of claim 4, wherein the one or more flex circuits further comprise a temperature sensing structure in proximity to at least one of the electrodes, the temperature sensing structure being electrically coupled to the processor so as to provide feedback.

7. The method of claim 1, further comprising monitoring and modifying energy delivery to the electrodes in response to a change in at least one of frequency range, impedance magnitude, impedance phase angle, temperature, power, voltage, and current, the change being associated with at least one of heating of tissue and proximity to an implanted structure.

8. The method of claim 7, wherein the processor halts energy delivery to one of the electrodes while continuing to energize and regulate energy delivery to another electrode.

9. The method of claim 3, wherein the balloon is inflated with an inflation pressure of about 10 atmospheres or less.

10. The method of claim 1, wherein an expanded diameter of the expandable structure is about 2 mm to about 10 mm.

11. The method of claim 1, wherein the processor characterizes tissue in the treatment zone using a tissue signature profile curve, within a frequency range, of impedance magnitude and phase angles of the at least one circuit.

12. The method of claim 11, wherein the processor characterizes the circuit so as to identify an implanted structure.

13. The method of claim 11, wherein the processor localizes and characterizes a plurality of materials about the vasculature, and selectively treats different characterized materials by applying different remodeling energy treatments to selected electrodes.

14. The method of claim 11, wherein the processor selectively energizes an electrode, and characterizes the tissue to be treated using at least one of a relative slope of the tissue signature profiles and an offset between the tissue signature profiles.

15. The method of claim 1, wherein the processor selectively energizes an electrode by modulating one or more of power, duty cycle, current, and voltage based on a monitored parameter of the electrical circuit.

16. The method of claim 1, wherein the electrodes are energized in a sequence.

17. The method of claim 16, wherein a first group of electrodes is energized in a sequence so as to define a first pattern of treatment zones, and wherein a second group of electrodes is energized in a sequence so as to define a second pattern of treatment zones, so as to minimize the gap between the first and second pattern of treatment zones.

18. The method of claim 1, wherein an electrode is energized with a power of 0.5 Watts to 20 Watts for 0.5 seconds to 180 seconds.

19. The method of claim 1, further comprising repositioning the catheter along a portion of the vasculature by collapsing the expandable structure, and moving the catheter to a subsequent location.

20. The method of claim 12, wherein energy delivery is selected by the processor based on a determination of a composition of the implanted structure in response to an impedance of the circuit.

21. The method of claim 1, wherein the power source includes a radiofrequency generator.

22. A system for delivering energy-based treatment for in-stent restenosis and other stenosis of the vasculature, the system comprising:

an elongate flexible catheter body having a proximal end and a distal end with an axis therebetween;

a radially expandable structure near the distal end of the catheter body;

a plurality of electrodes positioned on the radially expandable structure so as to engage tissue upon expansion of the radially expandable structure;

a power source coupled with the electrodes such that when an electrode engages tissue an electrical circuit comprising the power source, the electrode, and the engaged tissue is defined; and

,

a processor coupled with the power source, the processor configured to verify the presence of the electrical circuit, to selectively energize the engaged electrodes, and to control the delivery of energy by regulating one or more parameters of the electrical circuit based on monitoring feedback from the electrical circuit such that energy delivered to a tissue treatment zone heats tissue therein to a temperature of about 55°

C. to about 75°

C. while tissue collateral to the treatment zone is heated to less than about 45°

C., thereby inducing a tissue response that remodels stenosis and avoids a subsequently occluding tissue response caused by thermal damage.

23. The system of claim 22, wherein the plurality of electrodes are distributed about the circumference of the expanding structure so as to form an electrode array, the electrodes having an elongate shape oriented to be substantially parallel to the catheter axis upon expansion of the expandable structure.

24. The system of claim 22, wherein the expandable structure comprises a balloon.

25. The system of claim 24, wherein the electrodes positioned on the balloon are included in one or more flex circuit, the flex circuit including a monopolar electrode or a bipolar electrode pair.

26. The system of claim 22, wherein the electrodes include a radiopaque material.

27. The system of claim 25, wherein the one or more flex circuits further comprise a temperature sensing structure mounted thereon in proximity to at least one of the electrodes, the temperature sensing structure being electrically coupled to the processor so as to provide feedback for control for the power source.

28. The system of claim 22, wherein the processor is configured to monitor and modify energy delivery to an electrode by the power source in response to a change in at least one of frequency range, impedance magnitude, impedance phase angle, temperature, power, voltage, and current, the change being associated with at least one of heating of tissue and proximity to an implanted structure.

29. The system of claim 28, wherein the processor halts energy delivery to an electrode while optionally continuing to energize and regulate energy delivery to another electrode.

30. The system of claim 24, wherein the balloon inflation pressure is about 10 atmospheres or less.

31. The system of claim 22, wherein the expanded diameter of the expandable structure is about 2 mm to about 10 mm.

32. The system of claim 22, wherein the processor is configured to characterize tissue in a treatment zone using a tissue signature profile curve, within a frequency range, of impedance magnitude and phase angles of the circuit.

33. The system of claim 32, wherein the processor is configured to characterize tissue by comparing the tissue signature profile curve to at least one other tissue signature profile curve, by selectively energizing an electrode, so as identify at least one of tissue to be treated and an implanted structure.

34. The system of claim 32, wherein the processor is configured to localize and characterize a plurality of materials about the vasculature, and to selectively treat different characterized materials by applying different remodeling energy treatments to selected electrodes.

35. The system of claim 32, wherein the processor is configured to selectively energize an electrode, and by using at least one of a relative slope of the tissue signature profiles and an offset between the tissue signature profiles, characterize the tissue to be treated.

36. The system of claim 22, wherein the processor selectively energizes an electrode by modulating one or more of power, duty cycle, current, and voltage based on a monitored parameter of the electrical circuit.

37. The system of claim 22, wherein the electrodes are energized in a sequence.

38. The system of claim 37, wherein a first group of electrodes is energized in a sequence so as to define a first pattern of treatment zones, and wherein a second group of electrodes is energized in a sequence so as to define a second pattern of treatment zones, so as to minimize the gap between the first and second pattern of treatment zones.

39. The system of claim 22, wherein an electrode is energized with a power of 0.5 Watts to 20 Watts for 0.5 seconds to 180 seconds.

40. The system of claim 22, wherein the expandable structure may be expanded and collapsed so as to allow for repositioning of the catheter along a portion of the vasculature.

41. The system of claim 33, wherein energy delivery may be selected by the processor based on a determination of the composition of the implanted structure according to an impedance measurement.

42. The system of claim 22, wherein the power source is comprised to include a radiofrequency generator.

43. A method for treating in-stent restenosis, the method comprising:

placing an energy delivery catheter having a distal end comprised to include an expandable structure, with a plurality of electrodes thereon, proximate to an in-stent stenotic lesion;

expanding the expandable structure so as to engage an electrode with tissue such that an electrical circuit comprising the electrode and tissue is formed; and

,

energizing a selected electrode with a power source electrically coupled to the electrode so as to apply a remodeling energy sufficient to heat stenotic tissue to a temperature of about 55°

C. to about 75°

C. while tissue collateral to the stenosis is heated to less than about 45°

C., thereby inducing a tissue response that remodels stenosis and avoids a subsequently occluding tissue response caused by thermal damage.

44. A method for treating in-stent restenosis, the method comprising:

placing an energy delivery catheter having a distal end comprised to include an expandable structure with a plurality of energy delivery surfaces thereon proximate to an in-stent stenotic lesion;

expanding the expandable structure so as to place an energy delivery surface in sufficient proximity to stenotic tissue so as to allow energy to be transferred from the energy delivery surface to the tissue; and

,

energizing a selected energy delivery surface with a power source coupled to the energy delivery surface so as to apply a remodeling energy sufficient to heat stenotic tissue to a temperature of about 55°

C. to about 75°

C. while tissue collateral to the stenosis is heated to less than about 45°

C., thereby inducing a tissue response that remodels stenosis and avoids a subsequently occluding tissue response caused by thermal damage.

45. A catheter for delivering energy-based treatment for in-stent restenosis and other stenosis of the vasculature, the system comprising:

an elongate flexible catheter body having a proximal end and a distal end with an axis therebetween;

a radially expandable structure near the distal end of the catheter body; and

,

a plurality of electrodes positioned on the radially expandable structure so as to engage tissue at an electrode position upon expansion of the radially expandable structure, the tissue in proximity to engaged electrodes defining a tissue treatment zone.

46. The catheter of claim 45, wherein the plurality of electrodes are distributed about the circumference of the expanding structure so as to form an electrode array, the electrodes having an elongate shape oriented to be substantially parallel to the catheter axis upon expansion of the expandable structure.

47. The catheter of claim 45, wherein the expandable structure comprises a balloon.

48. The catheter of claim 47, wherein the electrodes positioned on the balloon are comprised of a flex circuit, the circuit being comprised to include a monopolar electrode or a bipolar electrode pair.

49. The catheter of claim 45, wherein the electrodes are comprised of a radiopaque material.

50. The catheter of claim 45, wherein one or more flex circuits further comprise a temperature sensing structure mounted thereon in proximity to at least one electrode, the temperature sensing structure being electrically coupled to the processor so as to comprise a means of feedback for control for the power source by sensing temperature in proximity to at least one electrode.

51. The catheter of claim 47, wherein the balloon inflation pressure is about 10 atmospheres or less.

52. The catheter of claim 45, wherein the expanded diameter of the expandable structure is about 2 mm to about 10 mm.

53. The catheter of claim 45, wherein the expandable structure may be expanded and collapsed so as to allow for repositioning of the catheter along a portion of the vasculature.

54. A method for delivering energy-based treatment for in-stent restenosis and other stenosis of the vasculature, the method comprising:

providing an elongate flexible catheter body having a proximal end and a distal end, a longitudinal axis extending therebetween, and a radially expandable structure disposed near the distal end, the expandable structure having a plurality of electrodes disposed thereon;

positioning the radially expandable structure at a location in the vasculature;

expanding the radially expandable structure so that the plurality of electrodes engage a tissue so as to define a tissue treatment zone;

energizing a circuit using a power source coupled with the electrodes such that when an electrode engages tissue an electrical circuit comprising the power source, the electrode, and the engaged tissue can be defined; and

controlling the delivery of energy using a processor coupled with the power source by selectively energizing the electrodes engaged with the tissue and regulating one or more parameters of the electrical circuit based on monitoring feedback from the electrical circuit such that energy delivered to a tissue treatment zone results in treated tissue being heated to a treatment temperature while avoiding a subsequent occluding tissue response in a collateral tissue caused by thermal damage.

55. A system for delivering energy-based treatment for in-stent restenosis and other stenosis of the vasculature, the system comprising:

an elongate flexible catheter body having a proximal end, a distal end, and a longitudinal axis extending therebetween;

a radially expandable structure disposed on the catheter body near the distal end thereof;

a plurality of electrodes positioned on the radially expandable structure so as to engage a tissue upon expansion of the radially expandable structure, the tissue in proximity to engaged electrodes defining a tissue treatment zone;

a power source coupled with the electrodes such that when an electrode of the plurality engages the tissue, an electrical circuit comprising the power source, the engaged electrode, and the tissue engaged by the electrode can be defined; and

a processor coupled with the power source, the processor configured to control the delivery of energy by regulating one or more parameters of the electrical circuit based on monitoring feedback acquired from the electrical circuit such that the controlled delivery of energy heats the tissue to be treated to a first treatment temperature while a collateral tissue adjacent the treatment zone is heated to a second temperature lower than the first treatment, wherein the second temperature is at least about 10 degrees Celsius lower than the first treatment temperature.