Tuned rf energy and electrical tissue characterization for selective treatment of target tissues

Abstract

A catheter and catheter system can use energy tailored for remodeling and/or removal of target material along a body lumen, often of atherosclerotic material of a blood vessel of a patient. An elongate flexible catheter body with a radially expandable structure may have a plurality of electrodes or other electrosurgical energy delivery surfaces to radially engage atherosclerotic material when the structure expands. An atherosclerotic material detector system may measure and/or characterize the atherosclerotic material and its location, optionally using impedance monitoring.

1 . An apparatus for renal neuromodulation, the apparatus comprising:
 a catheter configured for intravascular placement within a renal blood vessel of a human patient;   an expandable balloon at a distal portion of the catheter, wherein the expandable balloon is configured to vary between a delivery configuration and a deployed configuration sized to fit within the renal blood vessel;   a first electrode having a first pair of bipolar contacts attached to the expandable balloon; and   a second electrode having a second pair of bipolar contacts attached to the expandable balloon,   wherein the first electrode and the second electrode are spaced apart lengthwise and angularly offset from one another when the expandable balloon is in the deployed configuration,   wherein each of the first electrode and the second electrode is configured to deliver thermal energy to less than a full circumference of the renal blood vessel of the patient.   
     
     
         2 . The apparatus of  claim 1  wherein:
 the first electrode is configured to deliver thermal energy to create a first non-continuous, circumferential treatment zone along a lengthwise segment of the renal blood vessel; and 
 the second electrode is configured to deliver thermal energy to create a second non-continuous, circumferential treatment zone along the lengthwise segment of the renal blood vessel, 
 wherein the first circumferential treatment zone and the second circumferential treatment zone are formed in separate normal radial planes and are not continuous completely around the circumference of the renal blood vessel. 
 
     
     
         3 . The apparatus of  claim 2  wherein the first electrode and the second electrode are configured to respectively create the first circumferential treatment zone and second circumferential treatment zone in sequence. 
     
     
         4 . The apparatus of  claim 2  wherein the first electrode and the second electrode are configured to respectively create the first circumferential treatment zone and second circumferential treatment zone concurrently. 
     
     
         5 . The apparatus of  claim 1  wherein the first electrode and the second electrode are parts of a flex circuit on a surface of the expandable balloon. 
     
     
         6 . The apparatus of  claim 5  wherein the flex circuit terminates proximally to a distal end portion of the balloon. 
     
     
         7 . The apparatus of  claim 1  wherein the expandable balloon is configured to bring the first electrode and the second electrode into contact with an inner wall of the renal blood vessel when the expandable balloon is in the deployed configuration. 
     
     
         8 . The apparatus of  claim 1  wherein the expandable balloon is configured to block fluid flow within the renal blood vessel during energy delivery. 
     
     
         9 . The apparatus of  claim 1  wherein the expandable balloon is configured to not block fluid flow within the renal blood vessel during energy delivery. 
     
     
         10 . The apparatus of  claim 1 , further comprising:
 a third electrode having a third pair of bipolar contacts attached to the expandable balloon; and   a fourth electrode having a fourth pair of bipolar contacts attached to the expandable balloon,   wherein the third and fourth electrodes are spaced apart lengthwise and angularly offset from each other and from the first and second electrodes when the expandable balloon is in the deployed configuration,   wherein each of the electrodes are configured to deliver thermal energy to a less than a full circumference of the renal blood vessel of the patient.   
     
     
         11 . The apparatus of  claim 1  wherein the first electrode further comprises at least one sensor configured to monitor a parameter of the apparatus or of tissue within the patient. 
     
     
         12 . The apparatus of  claim 11 , further comprising a feedback control system configured to alter treatment in response to the monitored parameter. 
     
     
         13 . The apparatus of  claim 1  wherein the first and second electrodes are configured to deliver thermal energy sufficient to modulate neural activity in neural fibers within a wall of, or in proximity to, the renal blood vessel. 
     
     
         14 . The apparatus of  claim 1  wherein the first and second electrodes are configured to deliver thermal energy sufficient to ablate neural fibers within a wall of, or in proximity to, the renal blood vessel. 
     
     
         15 . The apparatus of  claim 1  wherein the catheter is configured for infusion of one or more agents into the renal blood vessel before, during, or after energy delivery. 
     
     
         16 . The apparatus of  claim 1 , further comprising an electric field generator external to the patient and electrically coupled to the first and second electrodes. 
     
     
         17 . An apparatus for treating a patient, the apparatus comprising:
 a catheter configured for intravascular placement within a blood vessel of a human patient;   an expandable balloon at a distal portion of the catheter, wherein the expandable balloon is configured to vary between a delivery configuration and a deployed configuration sized to fit within the blood vessel;   a first electrode having a first pair of bipolar contacts attached to the expandable balloon; and   a second electrode having a second pair of bipolar contacts attached to the expandable balloon,   wherein the first electrode and the second electrode are spaced apart lengthwise and angularly offset from one another when the expandable balloon is in the deployed configuration,   wherein each of the first electrode and the second electrode is configured to deliver thermal energy to less than a full circumference of the blood vessel of the patient.   
     
     
         18 . The apparatus of  claim 17  wherein:
 the first electrode is configured to deliver thermal energy to create a first non-continuous, circumferential treatment zone along a lengthwise segment of the blood vessel; and 
 the second electrode is configured to deliver thermal energy to create a second non-continuous, circumferential treatment zone along the lengthwise segment of the blood vessel, 
 wherein the first circumferential treatment zone and the second circumferential treatment zone are formed in separate normal radial planes and are not continuous completely around the circumference of the blood vessel. 
 
     
     
         19 . The apparatus of  claim 18  wherein the first electrode and the second electrode are configured to respectively create the first circumferential treatment zone and second circumferential treatment zone in sequence. 
     
     
         20 . The apparatus of  claim 18  wherein the first electrode and the second electrode are configured to respectively create the first circumferential treatment zone and second circumferential treatment zone concurrently. 
     
     
         21 . The apparatus of  claim 17  wherein the first electrode and the second electrode are parts of a flex circuit on a surface of the expandable balloon. 
     
     
         22 . The apparatus of  claim 21  wherein the flex circuit terminates proximally to a distal end portion of the balloon. 
     
     
         23 . The apparatus of  claim 17  wherein the expandable balloon is configured to bring the first electrode and the second electrode into contact with an inner wall of the blood vessel when the expandable balloon is in the deployed configuration. 
     
     
         24 . The apparatus of  claim 17  wherein the expandable balloon is configured to block fluid flow within the blood vessel during energy delivery. 
     
     
         25 . The apparatus of  claim 17  wherein the expandable balloon is configured to not block fluid flow within the blood vessel during energy delivery. 
     
     
         26 . The apparatus of  claim 17 , further comprising:
 a third electrode having a third pair of bipolar contacts attached to the expandable balloon; and   a fourth electrode having a fourth pair of bipolar contacts attached to the expandable balloon,   wherein the third and fourth electrodes are spaced apart lengthwise and angularly offset from each other and from the first and second electrodes when the expandable balloon is in the deployed configuration,   wherein each of the electrodes are configured to deliver thermal energy to a less than a full circumference of the blood vessel of the patient.   
     
     
         27 . The apparatus of  claim 17  wherein the first electrode further comprises at least one sensor configured to monitor a parameter of the apparatus or of tissue within the patient. 
     
     
         28 . The apparatus of  claim 27 , further comprising a feedback control system configured to alter treatment in response to the monitored parameter. 
     
     
         29 . The apparatus of  claim 17  wherein the first and second electrodes are configured to deliver thermal energy sufficient to modulate neural activity in neural fibers within a wall of, or in proximity to, the blood vessel. 
     
     
         30 . The apparatus of  claim 17  wherein the first and second electrodes are configured to deliver thermal energy sufficient to ablate neural fibers within a wall of, or in proximity to, the blood vessel. 
     
     
         31 . The apparatus of  claim 17  wherein the catheter is configured for infusion of one or more agents into the blood vessel before, during, or after energy delivery. 
     
     
         32 . The apparatus of  claim 17 , further comprising an electric field generator external to the patient and electrically coupled to the first and second electrodes.