Apparatus, systems, and methods for achieving intravascular, thermally-induced renal neuromodulation

Abstract

Apparatus, systems, and methods for achieving thermally-induced renal neuromodulation by intravascular access are disclosed herein. One aspect of the present application, for example, is directed to apparatuses, systems, and methods that incorporate a treatment device comprising an elongated shaft. The elongated shaft is sized and configured to deliver a thermal element to a renal artery via an intravascular path. Thermally-induced renal neuromodulation may be achieved via direct and/or via indirect application of thermal energy to heat or cool neural fibers that contribute to renal function, or of vascular structures that feed or perfuse the neural fibers.

1 - 14 . (canceled) 
   
   
       15 . A catheter apparatus, comprising:
 a thermal element;   an elongated shaft extending along an axis; and   a distal flexure zone separating the thermal element and the elongated shaft, wherein the distal flexure zone is configured to carry the thermal element and facilitate stable contact between the thermal element and a tissue surface, and further wherein the distal flexure zone comprises a flexible structure that accommodates passive flexure in any plane through the axis during contact between the thermal element and the tissue surface.   
   
   
       16 . The catheter apparatus of  claim 15  wherein the flexible structure is configured for up to ninety degrees of flexure from the axis. 
   
   
       17 . The catheter apparatus of  claim 15  wherein the distal flexure zone electrically isolates the thermal element from the elongated shaft. 
   
   
       18 . The catheter apparatus of  claim 15  wherein the distal flexure zone is configured to facilitate stable contact between a side of the thermal element and the tissue surface. 
   
   
       19 . The catheter apparatus of  claim 15  wherein the flexible structure comprises a polymer. 
   
   
       20 . The catheter apparatus of  claim 19  wherein the flexible structure further comprises a polymer thread. 
   
   
       21 . The catheter apparatus of  claim 20  wherein the polymer thread mechanically couples the flexible structure to at least one of the thermal element and the elongated shaft. 
   
   
       22 . The catheter apparatus of  claim 20  wherein the polymer thread comprises a Kevlar thread. 
   
   
       23 . The catheter apparatus of  claim 15  wherein the flexible structure further comprises a polymer laminate, coating or sheath. 
   
   
       24 . The catheter apparatus of  claim 23  wherein the polymer laminate, coating, or sheath comprises carbothane. 
   
   
       25 . The catheter apparatus of  claim 23  wherein the flexible structure further comprises a metal coil. 
   
   
       26 . The catheter apparatus of  claim 15  wherein the thermal element is configured to apply treatment to a tissue region adjacent to the tissue surface using at least one of radiofrequency energy, microwave energy, ultrasound energy, laser/light energy, thermal fluid, and cryogenic fluid. 
   
   
       27 . The catheter apparatus of  claim 15  wherein the thermal element comprises an electrode for applying radiofrequency energy to tissue. 
   
   
       28 . The catheter apparatus of  claim 15  wherein the distal flexure zone has a length of from about 2 millimeters to about 5 millimeters. 
   
   
       29 . The catheter apparatus of  claim 15  wherein the thermal element and the distal flexure zone together comprise an active, flexible electrode. 
   
   
       30 . The catheter apparatus of  claim 29  wherein:
 the elongated shaft comprises an intermediate flexure zone having a first diameter; and   the distal flexure zone has a second diameter equal to or greater than the first diameter.   
   
   
       31 . The catheter apparatus of  claim 29  wherein the flexible electrode comprises a distal portion having a generally blunt, atraumatic end surface. 
   
   
       32 . The catheter apparatus of  claim 15  wherein:
 the distal flexure zone has a first end adjacent to the elongated shaft and a second end opposite to the first end;   the thermal element is carried by the distal flexure zone between the first and second ends.   
   
   
       33 . The catheter apparatus of  claim 32  wherein the thermal element comprises a generally spherical electrode. 
   
   
       34 . The catheter apparatus of  claim 32  wherein the thermal element comprises a generally cylindrical electrode. 
   
   
       35 . The catheter apparatus of  claim 32  wherein:
 the elongated shaft comprises an intermediate flexure zone having a first diameter;   the distal flexure zone has a second diameter approximately equal to the first diameter; and   the thermal element has a third diameter greater than the first diameter and the second diameter.   
   
   
       36 . A medical treatment kit, comprising:
 a treatment device including—
 a treatment element; 
 an elongated shaft extending along an axis; and 
 a distal flexure zone separating the treatment element and the elongated shaft, wherein the distal flexure zone is configured to carry the treatment element and facilitate stable contact between the treatment element and a tissue surface of a patient, and further wherein the distal flexure zone comprises a flexible structure that accommodates passive flexure in any plane through the axis during contact between the thermal element and the tissue surface; 
   a cable configured to electrically connect the treatment device to a thermal generator;   a guide catheter configured to facilitate intravascular delivery of the treatment device into the patient; and   instructions for delivering the treatment device into a renal artery of the patient and at least partially denervating a kidney of the patient corresponding to the renal artery to treat the patient for a condition associated with at least one of hypertension, heart failure, kidney disease, chronic renal failure, sympathetic hyperactivity, diabetes, metabolic disorder, insulin resistance, arrhythmia, acute myocardial infarction, and cardio-renal syndrome.   
   
   
       37 . The medical treatment kit of  claim 36 , further comprising a dispersive electrode configured to provide a return path for an energy field from the treatment device. 
   
   
       38 . The medical treatment kit of  claim 36  wherein the cable is integral with the treatment device. 
   
   
       39 . The medical treatment kit of  claim 36  wherein the cable and the treatment device are discrete elements configured to be connected to each other. 
   
   
       40 . A system for thermally inducing neuromodulation of a renal plexus of a patient, the system comprising:
 an intravascular treatment device including—
 a treatment element configured for manipulation and use within a renal artery of the patient; 
 an elongated shaft extending along an axis; and 
 a distal flexure zone separating the treatment element and the elongated shaft, wherein the distal flexure zone is configured to carry the treatment element and facilitate stable contact between the treatment element and tissue along an interior wall of the renal artery, and further wherein the distal flexure zone comprises a flexible structure that accommodates passive flexure in any plane through the axis during contact between the thermal element and the tissue along an interior wall of the renal artery; and 
   an energy generator electrically connected to the treatment device,   wherein the system includes instructions that cause the energy generator to deliver energy to the treatment element according to a predetermined energy delivery profile.   
   
   
       41 . The system of  claim 40  wherein the predetermined energy delivery profile comprises:
 increasing energy delivery to a predetermined first power level over a first period of time;   maintaining energy delivery at the first power level for a second period of time; and   increasing energy delivery to a predetermined second power level if a temperature value of a treatment site or of the treatment element is less than a preset threshold temperature following the second period of time.