Bipolar Off-Wall Electrode Device for Renal Nerve Ablation

Abstract

A first spacing structure is provided at a distal end of a first catheter. The first spacing structure is configured to position at least one arterial electrode at a predefined distance away from a wall of the renal artery. A second spacing structure is provided at the distal end of the first catheter or at a distal end of a second catheter. The second spacing structure is configured to position at least one aortal electrode at a predefined distance away from a wall of the aorta. The arterial and aortal electrodes are operable as a bipolar electrode arrangement. The first and second spacing structures respectively maintain the arterial and aortal electrodes at a predefined distance away from the renal artery and aortal walls while electrical energy sufficient to ablate perivascular nerve tissue adjacent the renal artery and aortal walls is delivered by the bipolar electrode arrangement.

1 . An apparatus, comprising:
 a first catheter having a proximal end and a distal end;   a first spacing structure provided at the distal end of the first catheter, the first spacing structure configured for deployment in a patient's renal artery and to position at least one arterial electrode at a predefined distance away from a wall of the renal artery;   a second spacing structure provided at the distal end of the first catheter or at a distal end of a second catheter, the second spacing structure configured for deployment in the patient's aorta proximate the renal artery and to position at least one aortal electrode at a predefined distance away from a wall of the aorta;   the at least one arterial and aortal electrodes operable as a bipolar electrode arrangement; and   each of the first and second spacing structures respectively maintaining the at least one arterial and aortal electrodes at a predefined distance away from the renal artery and aortal walls while electrical energy sufficient to ablate perivascular nerve tissue adjacent the renal artery and aortal walls is delivered by the bipolar electrode arrangement.   
     
     
         2 . The apparatus of  claim 1 , wherein the first and second spacing structures comprise one or more electrically nonconductive spacers which extend outwardly farther than the at least one arterial and aortal electrodes. 
     
     
         3 . The apparatus of  claim 1 , wherein the first and second spacing structures comprise one or more electrically nonconductive spheres having a diameter greater than that of the at least one arterial and aortal electrodes. 
     
     
         4 . The apparatus of  claim 1 , wherein the first and second spacing structures comprise one or more electrically nonconductive bumps, curves, struts, or baskets. 
     
     
         5 . The apparatus of  claim 1 , wherein the first and second spacing structures are respectively supported by a common catheter. 
     
     
         6 . The apparatus of  claim 1 , wherein one of the first and second spacing structures is supported by a first catheter or sheath, and the other of the first and second spacing structures is supported by a second catheter or sheath. 
     
     
         7 . The apparatus of  claim 1 , wherein each of the at least one arterial electrodes is coupled to a separate electrical conductor extending along the first catheter. 
     
     
         8 . The apparatus of  claim 1 , wherein each of the at least one arterial and aortal electrodes is coupled to a separate conductor extending along the first catheter so that the at least one arterial and aortal electrodes can be energized independently. 
     
     
         9 . The apparatus of  claim 1 , wherein at least the first spacing structure comprises a helical wire. 
     
     
         10 . The apparatus of  claim 1 , wherein:
 the first spacing structure comprises a helical wire having a first diameter in its deployed configuration;   the second spacing structure comprise a helical wire having a second diameter in its deployed configuration; and   the second diameter is greater than the first diameter.   
     
     
         11 . The apparatus of  claim 1 , comprising a sheath dimensioned to receive the apparatus in a non-deployed configuration, the sheath configured to transport a fluid for delivery to the renal artery. 
     
     
         12 . The apparatus of  claim 1 , wherein one or both of the first and second spacing structures comprises a shape-memory member or a superelastic member. 
     
     
         13 . The apparatus of  claim 1 , comprising an external control unit electrically coupled to each of the at least one arterial and aortal electrodes and configured to supply energy to each of the at least one arterial and aortal electrodes in accordance with one or more predetermined activation patterns or sequences. 
     
     
         14 . The apparatus of  claim 13 , wherein the external control unit is configured to monitor tissue impedance between selected pairs of the at least one arterial and aortal electrodes. 
     
     
         15 . An apparatus, comprising:
 a first catheter having a proximal end and a distal end;   a first spacing structure provided at the distal end of the first catheter, the first spacing structure configured for deployment in a body vessel, chamber, cavity, organ, or tissue structure and to position at least one electrode at a predefined distance away from the body vessel, chamber, cavity, organ, or tissue structure;   a second spacing structure provided at the distal end of the first catheter or at a distal end of a second catheter, the second spacing structure configured to support at least one electrode and for deployment at a body location spaced apart from the at least one electrode of the first spacing structure;   the respective at least one electrodes operable as a bipolar electrode arrangement; and   at least the first spacing structure maintaining the at least one electrode at the predefined distance away from the body vessel, chamber, cavity, organ, or tissue structure while electrical energy sufficient to ablate target tissue adjacent the body vessel, chamber, cavity, organ, or tissue structure is delivered by the bipolar electrode arrangement.   
     
     
         16 . The apparatus of  claim 15 , wherein each of the first and second spacing structures is configured to respectively maintain the at least one electrode at a predefined distance away from the body vessel, chamber, cavity, organ, or tissue structure while electrical energy sufficient to ablate the target tissue is delivered by the bipolar electrode arrangement. 
     
     
         17 . The apparatus of  claim 15 , wherein the first and second spacing structures comprise one or more electrically nonconductive spacers which extend outwardly farther than the at least one electrodes, respectively. 
     
     
         18 . The apparatus of  claim 15 , comprising an external control unit electrically coupled to each of the at least one electrodes and configured to supply energy to each of the at least one electrodes in accordance with one or more predetermined activation patterns or sequences. 
     
     
         19 . The apparatus of  claim 15 , wherein one or both of the first and second spacing structures comprises a shape-memory member or a superelastic member. 
     
     
         20 . A method, comprising:
 causing a first support structure situated within or at a body vessel, chamber, cavity, organ, or tissue structure to transform between a low-profile introduction configuration and a larger-profile deployed configuration;   maintaining space between an electrode arrangement and the body vessel, chamber, cavity, organ, or tissue structure using the first support structure in the deployed configuration;   ablating target tissue adjacent the body vessel, chamber, cavity, organ, or tissue structure using the electrode arrangement and another electrode arrangement spaced apart from the electrode arrangement while the first support structure is in the deployed configuration; and   causing the first support structure to transform from the larger-profile deployed configuration to the low-profile introduction configuration after ablating the target tissue.   
     
     
         21 . The method of  claim 20 , comprising:
 causing a second support structure situated within or at a body vessel, chamber, cavity, organ, or tissue structure to transform between a low-profile introduction configuration and a larger-profile deployed configuration;   maintaining space between the other electrode arrangement and the body vessel, chamber, cavity, organ, or tissue structure using the second support structure in the deployed configuration;   ablating target tissue adjacent the body vessel, chamber, cavity, organ, or tissue structure using the respective electrode arrangements while the first and second support structures are in the deployed configuration; and   causing the first and second support structures to transform from the larger-profile deployed configuration to the low-profile introduction configuration after ablating the target tissue.