Cooled Conductive Balloon RF Catheter for Renal Nerve Ablation

• US 20120029511A1
• Filed: 07/22/2011
• Published: 02/02/2012
• Est. Priority Date: 07/30/2010
• Status: Active Grant

• Current Assignee: Boston Scientific Scimed, Inc. (Boston Scientific Corporation)
• Original Assignee: Boston Scientific Scimed, Inc. (Boston Scientific Corporation)
• Inventors: Smith, Scott, Koblish, Joe, Jenson, Mark L., Hastings, Roger
• Granted Patent: US 9,463,062 B2
• Time in Patent Office: Days
• US Class Current: 606/41
• 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 2018/00029 open
• CPC Class Codes: A61B 2018/00035 with return means
• CPC Class Codes: A61B 2018/00065 porous
• CPC Class Codes: A61B 2018/0016 Energy applicators arranged in a two- or three dimensional array
• CPC Class Codes: A61B 2018/0022 Balloons
• CPC Class Codes: A61B 2018/00238 porous
• CPC Class Codes: A61B 2018/00285 Balloons
• CPC Class Codes: A61B 2018/00404 Blood vessels other than those in or around the heart
• CPC Class Codes: A61B 2018/00434 Neural system
• CPC Class Codes: A61B 2018/00505 Urinary tract
• CPC Class Codes: A61B 2018/00511 Kidney
• CPC Class Codes: A61B 2018/00577 Ablation
• CPC Class Codes: A61B 2018/00821 measured by a thermocouple
• CPC Class Codes: A61B 2018/1472 for use with liquid electrolyte, e.g. virtual electrodes

Abstract

A catheter includes a flexible shaft having a lumen arrangement and a length sufficient to access a target vessel of a patient. A balloon at the distal end of the shaft is fluidly coupled to the lumen arrangement. The balloon body comprises a first material and a second material different from the first material. The second material comprises a hydrophilic polymer that becomes electrically conductive in response to absorption of the conductive fluid. The fluid conductive regions facilitate perfusion of the conductive fluid through the balloon body to an inner wall of the target vessel during ablation of perivascular tissues. A cooling arrangement is configured for one of receiving a thermal transfer fluid from the lumen arrangement or facilitating perfusion of blood passing through the target vessel to cool the balloon body during ablation of the perivascular tissues.

Claims

1. An apparatus, comprising:

a catheter comprising a flexible shaft having a proximal end, a distal end, a length, and a lumen arrangement extending between the proximal and distal ends, the length of the shaft sufficient to access a target vessel of a patient relative to a percutaneous access location;

a balloon provided at the distal end of the shaft and fluidly coupled to the lumen arrangement, the distal end of the shaft and the balloon dimensioned for deployment within the target vessel, the balloon comprising;

a balloon body comprising a first material;

an inlet manifold coupled to the lumen arrangement through which an electrically conductive liquid can pass into the balloon body; and

one or more fluid conductive regions provided on the balloon body and comprising a second material different from the first material, the second material comprising a hydrophilic polymer that becomes electrically conductive in response to absorption of the conductive liquid, the one or more fluid conductive regions facilitating perfusion of the conductive liquid through the balloon body to an inner wall of the vessel;

one or more electrical conductors extending at least partially along the shaft and terminating proximate or within the balloon body, the one or more electrical conductors configured to conduct electrical energy received from an external energy source to the one or more fluid conductive regions sufficient to ablate perivascular tissues proximate the target vessel; and

a cooling arrangement configured for at least one of receiving a thermal transfer fluid from the lumen arrangement and facilitating perfusion of blood passing through the vessel to cool the balloon body during ablation of the perivascular tissues.

2. The apparatus of claim 1, wherein the target vessel comprises a renal artery of the patient, and the perivascular tissues comprise renal nerves.

3. The apparatus of claim 1, wherein the second material comprises a fluid conductive thermoplastic polyurethane.

4. The apparatus of claim 1, wherein the balloon is configured to be pressurized to a pressure sufficient to facilitate perfusion of the conductive liquid through the one or more fluid conductive regions.

5. The apparatus of claim 1, wherein the one or more electrical conductors extend at least partially into the balloon and are positioned in a spaced-apart relationship with respect to the one or more fluid conductive regions.

6. The apparatus of claim 1, wherein the one or more electrical conductors extend along at least a portion of the balloon body and are connected to the one or more fluid conductive regions.

7. The apparatus of claim 1, wherein the balloon body comprises one or more electrically conductive pads at least partially encompassing the one or more fluid conductive regions, and the one or more electrical conductors extend along at least a portion of the balloon body and are connected to the electrically conductive pads.

8. The apparatus of claim 1, wherein the one or more fluid conductive regions define a helical strip electrode. or a series of spaced-apart spot electrodes that collectively have a helical shape.

9. The apparatus of claim 1, wherein the one or more fluid conductive regions define a circumferential strip electrode or a series of spaced-apart spot electrodes that collectively have a circumferential shape.

10. The apparatus of claim 1, wherein the lumen arrangement of the shaft comprises a guide lumen coupled to the inlet manifold of the balloon and dimensioned to receive a guide wire.

11. An apparatus, comprising:

a catheter comprising a flexible shaft having a proximal end, a distal end, a length, and a lumen arrangement extending between the proximal and distal ends, the length of the shaft sufficient to access a renal artery of a patient relative to a percutaneous access location;

a balloon provided at the distal end of the shaft and fluidly coupled to the lumen arrangement, the distal end of the shaft and the balloon dimensioned for deployment within the renal artery, the balloon comprising;

a balloon body formed of a hydrophilic polymer that becomes electrically conductive in response to absorption of a conductive liquid, the balloon body comprising a proximal conical section, a distal conical section, and a circumferential section defined between the proximal and distal conical sections and configured to contact a circumferential portion of an inner wall of the renal artery, the circumferential section having a thickness less than that of the proximal and distal conical sections sufficient to facilitate preferential perfusion of the conductive liquid through the circumferential section relative to the proximal and distal conical sections; and

an inlet manifold coupled to the lumen arrangement through which the electrically conductive liquid can pass into the balloon body;

an electrical conductor extending at least partially along the shaft and terminating proximate or within the balloon body, the electrical conductor coupled to an electrode positioned within the balloon body and configured to conduct electrical energy received from an external energy source to at least the circumferential section of the balloon body sufficient to ablate perivascular renal nerve tissue proximate the circumferential section; and

a cooling arrangement configured for at least one of receiving a thermal transfer fluid from the lumen arrangement and facilitating perfusion of blood passing through the renal artery to cool the balloon body during ablation of the perivascular renal nerve tissue.

12. The apparatus of claim 11, wherein the hydrophilic polymer comprises a fluid conductive thermoplastic polyurethane.

13. The apparatus of claim 11, wherein the balloon is configured to be pressurized to a pressure sufficient to facilitate perfusion of the conductive liquid preferentially through the circumferential section relative to the proximal and distal conical sections.

14. The apparatus of claim 11, wherein a length of the circumferential section is less than about half a length of the proximal and distal conical sections.

15. The apparatus of claim 11, wherein the electrical conductor terminates within the balloon body and is coupled to an electrode positioned within the balloon body, the electrode positioned in a space-apart relationship relative to the circumferential section.

16. The apparatus of claim 11, wherein the electrical conductor extends along at least the proximal conical section and connects with the circumferential section.

17. The apparatus of claim 11, wherein the balloon body comprises a metalized layer extending along at least the proximal conical section and connecting with the circumferential section.

18. The apparatus of claim 11, wherein the balloon body is formed of a single layer of the hydrophilic polymer.

19. The apparatus of claim 11, wherein the lumen arrangement of the shaft comprises a guide lumen coupled to the inlet manifold of the balloon and dimensioned to receive a guide wire.

20. A method, comprising:

passing an electrically conductive liquid into a balloon positioned within a renal artery of a patient, the balloon having a balloon body comprising a first material and one or more fluid conductive regions provided on the balloon body and comprising a second material different from the first material, the second material comprising a hydrophilic polymer that becomes electrically conductive in response to absorption of the conductive liquid, the one or more fluid conductive regions facilitating perfusion of the conductive liquid through the balloon body to an inner wall of the renal artery;

communicating electrical energy to the one or more fluid conductive regions sufficient to ablate perivascular renal nerve tissue proximate the renal artery; and

at least one of receiving a thermal transfer fluid and facilitating perfusion of blood passing through the renal artery to provide cooling to the balloon body during ablation of the perivascular renal nerve tissue.