Neuromodulation Catheter Devices and Systems Having Energy Delivering Thermocouple Assemblies and Associated Methods

Abstract

Catheter apparatuses, systems, and methods for achieving neuromodulation by intravascular access are disclosed herein. One aspect of the present technology, for example, is directed to a treatment device having a therapeutic assembly that includes an elongated tubular shaft having a pre-formed spiral shape when in a deployed state (e.g., a radially expanded, generally spiral/helical shape) and a thermocouple assembly helically wrapped about the shaft. In one embodiment, the thermocouple assembly comprises first and second wires composed of dissimilar metals with the first wire including a plurality of exposed and insulated regions along the distal portion of the treatment device. The exposed regions of the first wire define a plurality of energy delivery portions positioned to deliver electrical energy (e.g., RF energy, pulsed energy, etc.) to target tissue adjacent a wall of an artery (e.g., a renal artery) to heat or otherwise electrically modulate neural fibers that contribute to physiological function (e.g., renal function).

I/We claim: 
     
         1 . A method of manufacturing a medical device for neuromodulation, the method comprising:
 positioning a thermocouple assembly along a distal portion of a catheter, wherein the thermocouple assembly comprises a first wire and a second wire composed of dissimilar metals, and wherein the thermocouple assembly comprises a thermocouple junction at least proximate the distal portion;   wherein the first wire has a plurality of exposed and insulated regions along a portion of the first wire proximate the distal portion, and the second wire of the thermocouple assembly remains insulated; and   wherein the distal portion of the catheter includes an elongated tubular shaft configured to transform between a delivery configuration and a deployed configuration at a target treatment site within a blood vessel of a human patient, and wherein, in the deployed configuration, the exposed regions of the first wire define a plurality of energy delivery portions positioned to deliver energy to target tissue adjacent a wall of the blood vessel.   
     
     
         2 . The method of  claim 1  wherein disposing a thermocouple assembly along a distal portion of a catheter comprises helically positioning the thermocouple assembly about the shaft. 
     
     
         3 . The method of  claim 1  wherein the shaft comprises a tubular structure having a lumen therethrough and a self-expanding, shape-memory material disposed within the lumen. 
     
     
         4 . The method of  claim 1  wherein the shaft comprises a tubular structure having a lumen therethrough and is composed of a Nitinol multifilar stranded wire. 
     
     
         5 . The method of  claim 1  wherein the method further comprises coating the exposed regions of the first wire with a biocompatible conductive material. 
     
     
         6 . The method of  claim 1  wherein the exposed regions along the first wire of the thermocouple assembly are in electrical communication with each other. 
     
     
         7 . The method of  claim 1 , further comprising selectively removing portions of the first wire of the thermocouple assembly to define a plurality of exposed and insulated regions. 
     
     
         8 . The method of  claim 7  wherein selectively removing portions of the first wire of the thermocouple assembly comprises forming four exposed regions along the first wire. 
     
     
         9 . The method of  claim 1  wherein, in the deployed configuration, the shaft carrying the thermocouple assembly comprises a radially expanded, generally spiral shape configured to contact the wall of the blood vessel and to allow blood to flow through the vessel. 
     
     
         10 . The method of  claim 1 , further comprising disposing one or more sleeves composed of insulative material about the thermocouple assembly and the shaft. 
     
     
         11 . The method of  claim 10  wherein the sleeves comprise polyethylene terephthalate (PET) heat shrink tubing. 
     
     
         12 . The method of  claim 1  wherein the first wire is composed of copper and the second wire is composed of constantan. 
     
     
         13 . The method of  claim 1  wherein the first wire is composed of silver coated nickel and the second wire is composed of constantan. 
     
     
         14 . The method of  claim 1  wherein the first wire is composed of nickel and the second wire is composed of constantan. 
     
     
         15 . The method of  claim 1  wherein the first wire is composed of silver and the second wire is composed of constantan. 
     
     
         16 . A catheter apparatus, comprising:
 an elongated tubular shaft in a distal portion of the catheter apparatus, the shaft having a pre-formed spiral shape; and   a therapeutic assembly disposed at the distal portion of the catheter apparatus and adapted to be located at a target location within an artery of a human patient, the therapeutic assembly comprising a thermocouple assembly helically wrapped about the shaft, wherein the thermocouple assembly comprises a thermocouple junction at least proximate a distal portion of the shaft, and a first wire and a second wire composed of dissimilar metals, wherein the first wire comprises a plurality of exposed and insulated regions along the shaft, and further wherein the second wire is insulated along the shaft,   wherein the elongated tubular shaft and the therapeutic assembly together define therethrough a guide wire lumen configured to slideably receive a medical guide wire,   wherein axial movement of the guide wire relative to the therapeutic assembly transforms the shaft between (a) a low-profile delivery configuration and (b) a deployed configuration tending to assume the pre-formed spiral shape of the shaft,   wherein, in the deployed configuration, the exposed regions of the first wire define a plurality of energy delivery portions positioned to deliver energy to target tissue adjacent a wall of the artery.   
     
     
         17 . The catheter apparatus of  claim 16  wherein, in the deployed configuration, the energy delivery portions of the first wire are spaced apart from each other along a longitudinal axis of the artery and are configured to maintain apposition with a wall of the artery. 
     
     
         18 . The catheter apparatus of  claim 16  wherein the shaft comprises a tubular member having a lumen therethrough and is composed of a Nitinol multifilar stranded wire. 
     
     
         19 . The catheter apparatus of  claim 16  wherein the exposed regions along the first wire of the thermocouple assembly do not contact each other in the delivery or deployed configurations. 
     
     
         20 . The catheter apparatus of  claim 16  wherein the individual energy delivery portions are in electrical communication with each other. 
     
     
         21 . The catheter apparatus of  claim 16  wherein the first wire of the thermocouple assembly comprises four energy delivery portions. 
     
     
         22 . The catheter apparatus of  claim 16  wherein the therapeutic assembly does not include any electrodes. 
     
     
         23 . The catheter apparatus of  claim 16  wherein the energy delivery portions are configured to deliver a thermal radiofrequency field to target nerves adjacent the wall of the artery. 
     
     
         24 . A catheter system, comprising:
 an electric field generator configured to deliver radiofrequency (RF) energy to target tissue of a human patient;   a catheter having a distal portion configured for placement within a blood vessel of the patient;   a treatment assembly at the distal portion of the catheter, wherein the treatment assembly is selectively transformable between a low-profile delivery configuration and a deployed configuration sized to fit within the blood vessel;   a thermocouple arranged about the distal portion of the catheter and electrically connectable to the electric field generator, wherein the thermocouple comprises—
 a first conductive wire having a plurality of predefined uninsulated regions at the distal portion of the catheter that define RF energy delivery portions positioned to deliver RF energy to the target tissue when the treatment assembly is in the deployed configuration; 
 a second insulated wire adjacent to the first wire and composed of a different material than the first wire; and 
 a thermocouple junction at least proximate the distal portion of the catheter.