System for inducing desirable temperature effects on body tissue

• US 20080188912A1
• Filed: 10/18/2007
• Published: 08/07/2008
• 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: Stone, Corbett W., Perry, Mike, Hoey, Michael F., Gustus, Rolfe Tyson, Briggs, Len, Blanck, Arthur G.
• Granted Patent: US 9,125,667 B2
• Time in Patent Office: Days
• US Class Current: 607/99
• 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 2018/00702 Power or energy
• CPC Class Codes: A61B 2018/00875 Resistance or impedance
• CPC Class Codes: A61F 2007/126 for invasive application, e.g. for introducing into blood vessels
• CPC Class Codes: A61F 7/12 Devices for heating or cooling internal body cavities
• CPC Class Codes: A61F 7/123 using a flexible balloon containing the thermal element

Abstract

A catheter and catheter system may be used to treat disease tissue by gentle heating in combination with gentle or standard dilation. An elongate flexible catheter body with a radially expandable balloon having a plurality of electrodes engage tissue including diseased tissue when the structure expands.

Claims

1. A system for inducing desirable temperature effects on body tissue, the body tissue being disposed about a lumen, the system comprising:

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

a radially expandable member supported by the distal end of the catheter body, the expandable member having a low profile insertion configuration and a larger profile configuration; and

a plurality of electrodes disposed about the expandable member so as to define a plurality of remodeling zones in the tissue when the expandable member is in the large profile configuration within the lumen, the electrodes are radially coupled with the tissue, and tissue remodeling energy is transmitted between the electrodes and the tissue, the electrodes configured to inhibit vaporization along the lumen while the remodeling energy inhibits both acute and long-term occlusion of the lumen.

2. The system of claim 1, wherein radially expandable member comprises an elongate inflatable balloon having a proximal end, a distal end, and a median region therebetween, the electrodes being distributed along an axial length of the median region, a cross-section of the median region being sufficiently consistent to promote coupling of the electrodes to the arterial lumen throughout the axial length.

3. The system of claim 2, wherein the electrodes comprise a plurality of electrodes sets, each electrode of a set being electrically coupled together and to a conductor extending proximally along the catheter body, the electrodes of the set being sufficiently separated to allow flexing of the balloon along a length of the set, the electrodes of the set being sufficiently close that an associated contiguous remodeling zone is defined at least in part by the set.

4. The system of claim 3, wherein a first electrode set is offset from a second electrode set by a predetermined separation distance, the first and second electrode set comprising a bipolar pair so as to define the associated remodeling zone therebetween, the associated contiguous remodeling zone being elongate with a zone length along the lengths of the sets being greater than a zone width along the separation distance.

5. The system of claim 4, wherein the electrode sets of the pair extend axially along the median portion of the balloon so that the associated remodeling zone also extends axially, and further comprising a plurality of pairs of electrode sets, the pairs being separated circumferentially about the median portion of the balloon so that untreated tissue is disposed between a plurality of treatment zones.

6. The system of claim 4, wherein the electrode sets of the pair extend circumferentially about the median portion of the balloon so that the associated remodeling zone also extends circumferentially, and further comprising a plurality of pairs of electrode sets, the pairs being separated axially along the median portion of the balloon so that untreated tissue is disposed between a plurality of treatment zones.

7. The system of claim 2, wherein the electrodes have a predetermined separation distance therebetween, the separation distance being substantially independent of a pressure within a range of inflation pressures of the balloon when the balloon is in use and the electrodes are energized.

8. The system of claim 2, wherein the plurality of electrodes are arranged in a plurality of electrode flexible circuits distributed on the balloon.

9. The system of claim 8, wherein each flexible circuit extends along the axis and the flexible circuits are separated circumferentially about the balloon.

10. The system of claim 9, wherein each flexible circuit has at least one bipolar pair of electrodes, wherein the balloon has a plurality of folds to facilitate changes between the low profile configuration and the larger profile configuration, and wherein the folds are arranged between the electrodes of the pairs with bipolar conductors of each flexible circuit extending proximally from the electrodes on either side of an associated fold.

11. The system of claim 8, further comprising means for monitoring a distance between adjacent pairs of electrode flexible circuits.

12. The system of claim 1, wherein the electrodes are arranged as a plurality of elongate bipolar electrode band pairs, wherein the electrode bands of each pair are separated by a distance that inhibits, during the remodeling, heating of the tissue beyond a desired depth from the lumen so as to inhibit long-term occlusion, and wherein the electrode bands of the pair have a sufficient electrode width so as to inhibit, during the remodeling, charring and vaporization along the lumen, when the remodeling energy heats the tissue within the remodeling zones to a target surface temperature between 50°

C. and 65°

C. for less than 10 seconds.

13. The system of claim 1, wherein the electrodes are arranged as a plurality of elongate bipolar electrode band pairs, wherein the electrode bands of each pair are separated by a distance in a range from about 0.5 mm to about 2.5 mm, and wherein the electrode bands of the pair have an electrode width in a range from about 0.1 mm to about 0.5 mm.

14. The system of claim 2, wherein the balloon includes conductive electroplated portions, wherein the plurality of electrodes are coupled to the conductive electroplated portions on an inner surface of the balloon.

15. The system of claim 2, wherein the plurality of electrodes contain one or more materials with differing specific electrical conductivity on an outer surface of the balloon.

16. The system of claim 2, wherein each electrode comprises a metallic body affixed to the balloon by a polymer.

17. The system of claim 1, wherein the plurality of electrodes are configured to penetrate into a fibrous cap of the tissue.

18. The system of claim 1, wherein the expandable member is sized to fit the femoral, popliteal, coronary and/or carotid arteries.

19. The system of claim 1, wherein a controller energizes the electrodes by directing at least one of RF energy, microwave energy and ultrasound energy thereto.

20. A method for using a catheter system for inducing desirable temperature effects on desired body tissue of a patient, the body tissue being disposed about a lumen, the method comprising:

positioning a radially expandable member supported by a distal end of a catheter body within the lumen adjacent the desired tissue to be heated, the expandable member having a low profile insertion configuration and a larger profile configuration;

expanding the expandable member to the larger profile configuration within the lumen so as to engage a plurality of electrodes against the desired tissue, the plurality of electrodes defining a plurality of remodeling zones in the tissue;

energizing the plurality of electrodes with a controller having a power source electrically coupled to the plurality of electrodes; and

heating the remodeling zones in the tissue with the energized electrodes.

21. A method of making a catheter for use in a catheter system for inducing desirable temperature effects on desired body tissue of a patient, the body tissue being disposed about a lumen, the method comprising:

providing a balloon catheter having;

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

an inflatable balloon having a low profile insertion configuration and a larger profile configuration; and

attaching a plurality of electrodes to a surface of the balloon so as to define a plurality of remodeling zones in the tissue when the expandable member is in the large profile configuration within the lumen, with each electrode having an associated conductor extending proximally so as to electrically couple the plurality of electrodes to a controller and/or power supply.

22. The method of claim 21, wherein the plurality of electrodes are arranged in a plurality of electrode flexible circuits distributed on the balloon along the axis and the flexible circuits are separated circumferentially about the balloon.

23. The method of claim 22, wherein each flexible circuit has at least one bipolar pair of electrodes, wherein the balloon has a plurality of folds to facilitate changes between the low profile configuration and the larger profile configuration, and wherein the folds are arranged between the electrodes of the pairs with bipolar conductors of each flexible circuit extending proximally from the electrodes on either side of an associated fold.

24. The method of claim 21, wherein the plurality of electrodes contain materials of differing specific resistivity on an outer surface of the balloon.

25. The method of claim 21, wherein each electrode comprises a metallic body affixed to the balloon by a polymer.

26. The method of claim 21, wherein each electrode comprises a flattened wire affixed to the balloon.

27. The method of claim 21, wherein each electrode is a metal deposition on the balloon.

28. An apparatus for treatment of a blood vessel of a patient body, the vessel having a lumen and a vessel wall, the apparatus comprising:

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

a radially expandable member supported by the distal end of the catheter body, the expandable member having a low profile insertion configuration and a larger profile configuration;

a bipolar electrode pair carried by the expandable member so that expansion of the expandable member within the lumen urges the electrode pair against the vessel wall, the electrode pair providing a load impedance of from 20 to 4500 Ohms when delivering energy to tissues of the vessel wall when the tissues have a specific conductivity within a range from 0.2 to 0.5 Siemens per meter.

29. The apparatus of claim 28, further comprising an electrical energy source coupled to the electrode pair, the energy source configured to apply the energy, wherein the electrode pair provides the load impedance of from 40 to 2250 Ohms when delivering the energy to the tissues of the vessel wall when the tissues have a specific conductivity within the range.

30. The apparatus of claim 28, wherein the electrode pair provides the load impedance of from 50 to 1000 Ohms when delivering the energy to the tissues of the vessel wall when the tissues have a specific conductivity within the range.

31. The apparatus of claim 28, wherein the electrode pair provides the specified load impedance when the tissues have a specific conductivity of from 0.2 Siemens per meter to 0.35 Siemens per meter.

32. The apparatus of claim 28, wherein the electrode pair provides the specified load impedance when the tissues have a specific conductivity of from 0.35 Siemens per meter to 0.5 Siemens per meter.

33. The apparatus of claim 28, wherein a plurality of electrode pairs are carried by the expandable member, each electrode pair extending axially and providing an associated load impedance within the range when delivering energy to tissues of the vessel wall and when the tissues have a specific conductivity within the range.

34. The apparatus of claim 28, further comprising an electrical energy source coupled to the electrode pair, the energy source configured to apply the energy, wherein a spacing between adjacent internal edges of the electrodes of the pair is from about 0.25 mm to about 2.5 mm.

35. The apparatus of claim 28, wherein a spacing between adjacent internal edges of the electrode pair is from about 0.50 mm to about 2.00 mm.

36. The apparatus of claim 28, wherein a spacing between adjacent internal edges of the electrode pair is from about 0.75 mm to about 1.50 mm.

37. A method for treatment of a blood vessel of a patient body, the vessel having a lumen and a vessel wall, the method comprising:

radially expanding a member within the lumen so as to urge a bipolar electrode pair against the vessel wall;

delivering energy to the electrode pair while tissue of the vessel wall engaged by the electrode pair provides a load impedance of from 20 to 4500 Ohms.

38. The method of claim 37, wherein the tissue engaged by the electrode pair provides the load impedance of from 40 to 2250 Ohms.

39. The method of claim 37, wherein the tissue engaged by the electrode pair provides the load impedance of from 50 to 1000 Ohms.

40. The method of claim 37, wherein the energy is delivered while a spacing between adjacent internal edges of the electrode pair is from about 0.25 mm to about 2.5 mm.

41. The method of claim 37, wherein the energy is delivered while a spacing between adjacent internal edges of the electrode pair is from about 0.50 mm to about 2.00 mm.

42. The method of claim 37, wherein the energy is delivered while a spacing between adjacent internal edges of the electrode pair is from about 0.75 mm to about 1.50 mm.

43. The method of claim 37, wherein a plurality of electrode pairs urged against the vessel wall, each electrode pair extending along an axis of the vessel and providing an associated load impedance within the range when delivering energy to tissues of the vessel wall.

44. An apparatus for treatment of a blood vessel of a patient body, the vessel having a lumen and a vessel wall, the apparatus comprising:

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

a radially expandable member supported by the distal end of the catheter body, the expandable member having a low profile insertion configuration and a larger profile configuration;

a bipolar electrode pair carried by the expandable member so that expansion of the expandable member within the lumen urges the electrode pair against the vessel wall, the electrode pair having an inner edge spacing of x mm and a length of L mm; and

an electrical energy source configured to apply a power in Watts for a time of t seconds such that;

power=b*x̂

2*L*(t̂

(−

0.59)),

wherein b is a parameter in a range of 0.2 to 0.6.

45. A method for treatment of a blood vessel of a patient body, the vessel having a lumen and a vessel wall, the method comprising:

engaging a bipolar electrode pair against the vessel wall from within the lumen, the electrode pair having an inner edge spacing of x mm and a length of L mm; and

applying a power in Watts to the vessel wall with the electrode pair for a time of t seconds such that;

power=b*x̂

2*L*(t̂

(−

0.59)),

wherein b is a parameter in a range of 0.2 to 0.6.