Cooled conductive balloon rf catheter for renal nerve ablation

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.

1 .- 20 . (canceled) 
     
     
         21 . A medical apparatus, comprising:
 a catheter comprising a flexible shaft having a proximal end and a distal end, and a lumen therebetween;   a balloon body at the distal end of the shaft fluidly coupled to the lumen and comprising one or more fluid conductive regions provided in a pattern surrounding the circumference of the balloon body, the fluid conductive regions comprising a polymer that becomes electrically conductive in response to absorption of a conductive fluid from within the balloon body; and   an electrical conductor coupled to one or more electrodes associated with the balloon body, wherein the conductor provides electrical energy received from an energy source to the electrodes.   
     
     
         22 . The apparatus of  claim 21 , wherein the pattern of the fluid conductive regions defines one or more of a circumferential strip electrode or series of spaced-apart spot electrodes that collectively have a circumferential shape. 
     
     
         23 . The apparatus of  claim 21 , wherein the pattern of the fluid conductive regions defines one or more of a helical strip electrode or series of spaced-apart spot electrodes that collectively have a helical shape. 
     
     
         24 . The apparatus of  claim 21 , wherein the fluid conductive regions comprise a reduced wall thickness of the balloon body. 
     
     
         25 . The apparatus of  claim 24 , wherein the reduced wall thickness is sufficient to facilitate preferential perfusion of the conductive fluid through the balloon body at the fluid conductive regions. 
     
     
         26 . The apparatus of  claim 21 , wherein the one or more electrodes are positioned within the balloon body in a space-apart relationship relative to a wall of the balloon body, and the electrical conductor terminates within the balloon body and is coupled to the electrodes. 
     
     
         27 . The apparatus of  claim 21 , wherein the one or more electrodes are positioned on a wall of the balloon body corresponding to the fluid conductive regions, and the electrical conductor extends along the wall of the balloon body and is coupled to the electrodes. 
     
     
         28 . A medical apparatus, comprising:
 a catheter comprising a flexible shaft and having a length sufficient to access target tissue proximate a target vessel of a patient relative to a percutaneous access location;   a lumen extending along the length of the shaft through which an electrically conductive fluid can pass;   a balloon body comprising a first material provided at the distal end of the shaft and fluidly coupled to the lumen to receive the electrically conductive fluid;   one or more fluid conductive regions provided in a pattern on the balloon body around the circumference of the balloon body, the fluid conductive regions comprising a second material different from the first material that becomes electrically conductive in response to absorption of the conductive fluid; and   one or more electrical conductors configured to conduct electrical energy received from an external energy source to the fluid conductive regions.   
     
     
         29 . The apparatus of  claim 28 , wherein the pattern of the fluid conductive regions defines one or more of a circumferential strip electrode or series of spaced-apart spot electrodes that collectively have a circumferential shape. 
     
     
         30 . The apparatus of  claim 28 , wherein the pattern of the fluid conductive regions defines one or more of a helical strip electrode or series of spaced-apart spot electrodes that collectively have a helical shape. 
     
     
         31 . The apparatus of  claim 28 , wherein the target vessel comprises a renal artery of the patient, and the target tissue is perivascular tissue comprising renal nerves. 
     
     
         32 . The apparatus of  claim 28 , wherein the second material is of a reduced thickness compared to the first material. 
     
     
         33 . The apparatus of  claim 28 , 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. 
     
     
         34 . A method, comprising:
 passing an electrically conductive fluid into a balloon positioned within a body lumen of a patient, the balloon having a balloon body comprising one or more fluid conductive regions provided in a pattern surrounding the circumference of the balloon body, the fluid conductive regions comprising a polymer that becomes electrically conductive in response to absorption of the conductive fluid, the fluid conductive regions facilitating perfusion of the conductive fluid through the balloon body to an inner wall of the body lumen; and   communicating electrical energy to the fluid conductive regions sufficient to treat target tissue proximate the body lumen.   
     
     
         35 . The method of  claim 34 , wherein the pattern of the fluid conductive regions defines one or more of a circumferential strip electrode or series of spaced-apart spot electrodes that collectively have a circumferential shape. 
     
     
         36 . The method of  claim 34 , wherein the pattern of the fluid conductive regions defines one or more of a helical strip electrode or series of spaced-apart spot electrodes that collectively have a helical shape. 
     
     
         37 . The method of  claim 34 , wherein the body lumen is a renal artery and the target tissue is perivascular renal nerve tissue proximate the renal artery. 
     
     
         38 . The method of  claim 34 , further comprising receiving a thermal transfer fluid to provide cooling to the balloon body during treatment of the target tissue. 
     
     
         39 . The method of  claim 34 , wherein the balloon body comprises a first material and the polymer of the fluid conductive regions comprises a second material different from the first material. 
     
     
         40 . The method of  claim 34 , wherein the polymer of the fluid conductive regions is hydrophilic.