Systems, devices, and methods for modulating renal nerve tissue

Abstract

Methods for treating a patient using therapeutic renal neuromodulation and associated devices, system, and methods are disclosed herein. One aspect of the present technology is directed to neuromodulating nerve tissue in selected anatomical regions. In one embodiment, the method can include intravascularly advancing an elongate shaft of a catheter to renal vasculature of a human patient and locating a first neuromodulation element of the catheter within a distalmost portion of a main renal artery. The method includes locating a second neuromodulation element of the catheter within a branch vessel of the renal artery distal to a bifurcation at a distal end of the main renal artery. Neuromodulation of the nerve tissue surrounding the selected anatomical treatment locations can inhibit sympathetic neural activity in nerves proximate a portion of a renal artery and/or a renal branch artery proximate a renal parenchyma.

I/We claim: 
     
         1 . A method, comprising:
 intravascularly advancing an elongate shaft of a catheter to renal vasculature of a human patient;   locating a first neuromodulation element of the catheter within a distalmost portion of a main renal artery directly connected to an aorta of the patient and extending distally toward a kidney of the patient;   locating a second neuromodulation element of the catheter within a branch vessel of the renal artery distal to a bifurcation at a distal end of the main renal artery;   modulating nerve tissue within an anatomical region extending about the distalmost portion of the main renal artery via the first neuromodulation element; and   modulating nerve tissue within an anatomical region extending about the branch vessel via the second neuromodulation element.   
     
     
         2 . The method of  claim 1  wherein intravascularly advancing an elongate shaft of a catheter to renal vasculature comprises delivering the catheter over a guidewire, and wherein the first neuromodulation element assumes a preformed spiral/helical configuration within the distalmost portion of the main renal artery when the guidewire is retracted. 
     
     
         3 . The method of  claim 1  wherein intravascularly advancing an elongate shaft of a catheter to renal vasculature comprises delivering the catheter within a sheath, and wherein the first neuromodulation element assumes a preformed spiral/helical configuration within the distalmost portion of the main renal artery when removed from the sheath. 
     
     
         4 . The method of  claim 1  wherein the second neuromodulation element is operably connected to the shaft. 
     
     
         5 . The method of  claim 1  wherein the second neuromodulation element is operably connected to the first neuromodulation element. 
     
     
         6 . The method of  claim 1  wherein the second neuromodulation element comprises at least one wire electrode, and wherein locating the second neuromodulation element of the catheter within the branch vessel comprises delivering the second neuromodulation element to the branch vessel in a low-profile state and transforming the second neuromodulation element to an unconstrained spiral/helical state within the branch vessel. 
     
     
         7 . The method of  claim 1  wherein the second neuromodulation element comprises multiple wire electrodes, and wherein locating the second neuromodulation element of the catheter within the branch vessel comprises locating a first wire electrode within a first branch vessel and a second wire electrode within a second, different branch vessel. 
     
     
         8 . The method of  claim 1  wherein the first and second neuromodulation elements are a single continuous elongate element, and wherein:
 locating a first neuromodulation element of the catheter within a distalmost portion of a main renal artery comprises locating a proximal portion of the single elongate element within the distalmost portion of the main renal artery; and 
 locating a second neuromodulation element of the catheter within a branch vessel comprises locating a distal portion of the single elongate element within the branch vessel. 
 
     
     
         9 . The method of  claim 1  wherein the first neuromodulation element further comprises a balloon, and wherein locating the first neuromodulation element of the catheter within the distalmost portion of the main renal artery comprises inflating the balloon before modulating nerve tissue via the first neuromodulation element. 
     
     
         10 . The method of  claim 1  wherein the second neuromodulation element further comprises a balloon, and wherein locating the second neuromodulation element of the catheter within the branch vessel comprises inflating the balloon before modulating nerve tissue via the second neuromodulation element. 
     
     
         11 . The method of  claim 1  wherein modulating nerve tissue via the second neuromodulation element comprises forming a plurality of lesions, and wherein the proximalmost lesion is at least about 5 mm distal to the bifurcation of the main renal artery. 
     
     
         12 . The method of  claim 1  wherein modulating nerve tissue via the first neuromodulation element comprises forming a plurality of lesions, and wherein the proximalmost lesion is at least about 2 mm to 6 mm distal to the bifurcation of the main renal artery. 
     
     
         13 . The method of  claim 1  wherein the branch vessel is modulated before the main renal artery is modulated. 
     
     
         14 . The method of  claim 1  wherein the main renal artery is modulated before the branch vessel is modulated. 
     
     
         15 . The method of  claim 1  wherein the main renal artery and the branch vessel are modulated simultaneously. 
     
     
         16 . A method, comprising:
 intravascularly advancing an elongate shaft of a catheter to renal vasculature of a human patient;   locating a neuromodulation element of the catheter within a distalmost portion of a main vessel directly connected to an aorta of the patient and extending distally toward a kidney, wherein the neuromodulation element includes an elongate support structure having a plurality of longitudinally spaced-apart electrodes; and   ablating nerve tissue within an anatomical region extending circumferentially around the distalmost portion of the main vessel via the electrodes of the neuromodulation element.   
     
     
         17 . The method of  claim 16  wherein:
 the main vessel has a longitudinal axis extending from the aorta to a bifurcation at a distal end of the main renal artery; 
 ablating nerve tissue within the anatomical region extending circumferentially around the distalmost portion of the main vessel includes using the neuromodulation element to form one or more lesions extending through a wall of the main vessel into the anatomical region extending circumferentially around the distalmost portion of the main vessel; and 
 the one or more lesions collectively are—
 circumferentially continuous within the anatomical region along a plane perpendicular to a portion of the longitudinal axis extending through the distalmost portion of the main vessel, and 
 circumferentially discontinuous at the wall of the main vessel along all planes perpendicular to the portion of the longitudinal axis extending through the distalmost portion of the main vessel. 
 
 
     
     
         18 . The method of  claim 16  wherein the main vessel is stented, and wherein locating a neuromodulation element of the catheter within a distalmost portion of the main vessel includes locating the neuromodulation element distal to a stent. 
     
     
         19 . The method of  claim 16  wherein:
 the catheter, the shaft, and the neuromodulation element are a first catheter, a first shaft, and a first neuromodulation element, respectively; and 
 the method further comprises—
 withdrawing the first catheter from the patient; 
 intravascularly advancing an elongate second shaft of a second catheter to the renal vasculature; 
 locating a second neuromodulation element of the second catheter within a branch vessel of the renal vasculature distal to the bifurcation; 
 ablating nerve tissue within an anatomical region extending circumferentially around the branch vessel via the second neuromodulation element; and 
 
 withdrawing the second catheter from the patient. 
 
     
     
         20 . The method of  claim 19 , further comprising measuring a degree of neuromodulation achieved using the first neuromodulation element to modulate nerve tissue within the anatomical region extending circumferentially around the distalmost portion of the main vessel, and wherein locating the second neuromodulation element and ablating nerve tissue within the anatomical region extending circumferentially around the branch vessel includes locating the second neuromodulation element and using the second neuromodulation element to modulate nerve tissue within the anatomical region extending circumferentially around the branch vessel in response to an insufficiency of the degree of neuromodulation. 
     
     
         21 . The method of  claim 19  wherein ablating nerve tissue within an anatomical region extending circumferentially around the branch vessel includes modulating nerve tissue with a first power level, and wherein modulating nerve tissue within an anatomical region extending circumferentially around the main vessel includes modulating nerve tissue with a second power level greater than the first power level. 
     
     
         22 . The method of  claim 16  wherein:
 advancing the shaft includes advancing the shaft while the neuromodulation element is in a low-profile delivery state; and 
 the method further comprises transforming the neuromodulation element between the low-profile delivery state and an expanded treatment state after locating the neuromodulation element within the distalmost portion of the main vessel and before ablating nerve tissue within the anatomical region extending circumferentially around the distalmost portion of the main vessel, 
 wherein, in the extended treatment state, the neuromodulation element has a helical form. 
 
     
     
         23 . A method for treating a human patient diagnosed with a measurable physiological parameter associated with systemic sympathetic overactivity or hyperactivity, the method comprising:
 ablating renal nerves within an anatomical region extending about a branch renal vessel of the patient, wherein the branch renal vessel is located distal to a bifurcation in a main renal artery of the patient; and   ablating renal nerves within an anatomical region extending circumferentially around the main renal artery of the patient,   wherein ablating the renal nerves results in a decrease in renal sympathetic neural activity in the patient.   
     
     
         24 . The method of  claim 23  wherein ablating the renal nerves results in a therapeutically beneficial reduction in clinical symptoms of hypertension in the patient. 
     
     
         25 . The method of  claim 23  wherein ablating the renal nerves comprises systemically reducing sympathetic tone in the patient. 
     
     
         26 . The method of  claim 23  wherein ablating the renal nerves reduces norepinephrine spillover in the patient.