Electrical mapping and cryo ablating with a balloon catheter

• US 20090299355A1
• Filed: 05/27/2008
• Published: 12/03/2009
• Est. Priority Date: 05/27/2008
• Status: Active Grant

• Current Assignee: Boston Scientific Scimed (Boston Scientific Corporation)
• Original Assignee: Boston Scientific Scimed (Boston Scientific Corporation)
• Inventors: Chun, Byron, Mazzone, Jim, Tin, Rebecca, Koblish, Joe, Bencini, Bob, Ingle, Frank, Lawrence, David
• Granted Patent: US 8,128,617 B2
• Time in Patent Office: Days
• US Class Current: 606/21
• CPC Class Codes: A61B 18/02 by cooling, e.g. cryogenic techniques devices for cooling specific reflex points of the body within cell-life limits A61H39/06
• CPC Class Codes: A61B 2018/00017 with gas
• CPC Class Codes: A61B 2018/00023 closed, i.e. without wound contact by the fluid
• CPC Class Codes: A61B 2018/0022 Balloons
• CPC Class Codes: A61B 2018/00714 Temperature
• CPC Class Codes: A61B 2018/00791 Temperature
• CPC Class Codes: A61B 2018/00797 measured by multiple temperature sensors
• CPC Class Codes: A61B 2018/0212 using an instrument inserted into a body lumen, e.g. catheter
• CPC Class Codes: A61B 2018/0262 using a circulating cryogenic fluid
• CPC Class Codes: A61B 5/287 Holders for multiple electrodes, e.g. electrode catheters for electrophysiological study [EPS]

Abstract

In some implementations, a method of ablating body tissue includes (a) locating an inflatable balloon portion of a cryotherapy balloon catheter at a treatment site internal to a patient'"'"'s body, and inflating the inflatable balloon portion; (b) employing electrodes that are disposed on an expandable surface of the inflatable balloon portion to electrically characterize body tissue at the treatment site; (c) ablating the body tissue by supplying a cryotherapy agent to the inflatable balloon portion to cool the body tissue to a therapeutic temperature; (d) employing the electrodes to determine whether the ablating caused desired electrical changes in the body tissue; and (e) repeating (c) and (d) when it is determined that the ablating did not cause the desired electrical changes.

Claims

1. A method of ablating body tissue, the method comprising:

(a) locating an inflatable balloon portion of a cryotherapy balloon catheter at a treatment site internal to a patient'"'"'s body, and inflating the inflatable balloon portion;

(b) employing electrodes that are disposed on an expandable surface of the inflatable balloon portion to electrically characterize body tissue at the treatment site;

(c) ablating the body tissue by supplying a cryotherapy agent to the inflatable balloon portion to cool the body tissue to a therapeutic temperature;

(d) employing the electrodes to determine whether the ablating caused desired electrical changes in the body tissue; and

(e) repeating (c) and (d) when it is determined that the ablating did not cause the desired electrical changes.

2. The method of claim 1, further comprising removing the inflatable balloon portion from the treatment site when it is determined that the ablating caused the desired electrical changes.

3. The method of claim 1, further comprising locating the inflatable balloon portion at a second treatment site internal to the patient'"'"'s body and performing actions (b)-(e) at the second treatment site.

4. The method of claim 1, further comprising employing the electrodes to electrically characterize the body tissue while the body tissue is being ablated.

5. The method of claim 1, wherein employing the electrodes to determine whether the ablating caused desired electrical changes in the body tissue comprises allowing the body tissue to warm to a nominal temperature, and determining based on electrical characteristics of the body tissue at the nominal temperature.

6. The method of claim 1, wherein performing actions (b)-(d) comprises performing all of actions (b)-(d) while the balloon portion is at a fixed location relative to the treatment site.

7. A method of ablating body tissue, the method comprising:

(a) locating an inflatable balloon portion of a cryotherapy balloon catheter at a treatment site internal to a patient'"'"'s body, and inflating the inflatable balloon portion;

(b) employing electrodes that are disposed on an expandable surface of the inflatable balloon portion to electrically characterize body tissue at the treatment site;

(c) when electrical characterization in (b) indicates that ablation is indicated for the body tissue at the treatment site, supplying a cryotherapy agent to the inflatable balloon portion to cool the body tissue to a first, temporarily therapeutic temperature that does not cause permanent tissue alteration, and employing the electrodes to electrically characterize the body tissue at the first, temporarily therapeutic temperature;

(d) when electrical characterization in (c) indicates that the cooling reduces undesirable electrical activity in the body tissue, supplying additional cryotherapy agent to cool the body tissue to a second temperature that is lower than the first temperature and that causes permanent tissue alteration;

(e) after the body tissue has warmed to a temperature that is greater than the first temperature, employing the electrodes to determine whether the cooling to the second temperature caused desired electrical changes in the body tissue, and repeating (d) when it is determined that the cooling to the second temperature did not cause the desired electrical changes.

8. The method of claim 7, further comprising removing the inflatable balloon portion from the treatment site when it is determined that the cooling to the second temperature caused the desired electrical changes.

9. The method of claim 8, further comprising locating the inflatable balloon portion at a second treatment site internal to the patient'"'"'s body and performing (b)-(e) at the second treatment site.

11. The method of claim 7, wherein electrically characterizing body tissue comprises sensing, over a period of time, electrical potentials at a plurality of points on the body tissue at the treatment site, and identifying from the sensed electrical potentials aberrant electrical pathways in the body tissue.

10. The method of 7, wherein performing (b)-(e) comprises performing all of (b)-(e) without relocating the inflatable balloon portion between any of actions (b)-(e).

12. A method of ablating body tissue, the method comprising:

(a) providing a cryotherapy balloon catheter at a treatment site internal to the body of a patient, the cryotherapy balloon catheter having an inflatable balloon portion at a distal end, the inflatable balloon portion having disposed thereon a plurality of electrodes configured to sense electrical potentials of body tissue that is in contact with the plurality of electrodes;

(b) inflating the inflatable balloon portion such that the plurality of electrodes are in contact with body tissue at the treatment site, and employing the plurality of electrodes to initially electrically characterize body tissue at the treatment site;

(c) ablating the body tissue at the treatment site by supplying a cryotherapy agent to the inflatable balloon portion to cool the body tissue to a therapeutic temperature;

(d) employing the plurality of electrodes to electrically characterize body tissue at the treatment site to confirm that the ablating caused a desired change in electrical properties of the body tissue.

13. The method of claim 12, further comprising (e) deflating the inflatable balloon portion, and removing the cryotherapy balloon catheter from the treatment site.

14. The method of 13, wherein the inflatable balloon portion comprises splines that are configured to exert inward radial force on the inflatable balloon portion to facilitate the deflating in (e).

15. The method of 14, wherein the plurality of electrodes are disposed on the splines.

16. A cryotherapy catheter comprising:

an elongate member and an inflatable balloon at a distal end of the elongate member, the elongate member having lumens formed therein to supply a cryogenic agent to a chamber of the inflatable balloon to cool an outer surface portion of the inflatable balloon and body tissue that is in contact with the outer surface portion during a cryotherapy procedure, and to channel exhaust from the inflatable balloon chamber; and

a plurality of electrodes disposed at a corresponding plurality of electrode sites on the outer surface portion and configured to measure electrical potentials of the body tissue before, during and after cryogenic agent is supplied to the chamber.

17. The cryotherapy catheter of claim 16, wherein the inflatable balloon comprises splines that are disposed on the inflatable balloon longitudinally relative to an axis that is common to the inflatable balloon and the elongate member.

18. The cryotherapy catheter of claim 17, wherein the splines comprise a material selected from the group consisting of Nitinol, spring steel, and stainless steel.

19. The cryotherapy catheter of claim 17, wherein the splines comprise a plastic with memory.

20. The cryotherapy catheter of claim 17, wherein the splines are biased in a collapsed position and configured to exert force on the inflatable balloon to assist in collapsing the balloon following the cryotherapy procedure.

21. The cryotherapy catheter of claim 20, further comprising a sheath that surrounds the elongate member, through which the elongate member is translated during the cryotherapy procedure.

22. The cryotherapy catheter of claim 21, wherein a proximal portion of one or more of the splines comprises a protrusion configured to cooperate with a distal end of the sheath to exert radial pressure on the inflatable balloon as the elongate member is retracted into the sheath, to collapse the inflatable balloon.

23. The cryotherapy catheter of claim 17, wherein a material that makes up the inflatable balloon is substantially uniform in thickness, except for regions corresponding to the splines, which are thicker.

24. The cryotherapy catheter of claim 17, wherein the plurality of electrode sites are disposed on one or more of the splines.

25. The cryotherapy catheter of claim 16, wherein the plurality of electrode sites are all disposed on a distal hemisphere of the inflatable balloon.