Renal Nerve Neuromodulation Device

Abstract

A neuromodulation device includes an ablation valve with electrodes provided about its circumference. The valve dynamically reacts to fluid pressure within the vessel. When a pressure within and distal said ablation valve is greater than the body fluid pressure within the vessel, said ablation valve closes and the electrodes move out of contact with the endothelium of the vessel. When a pressure within and distal the ablation valve is less than the body fluid pressure upstream of the valve, the valve opens such that the electrodes are in circumferential contact with the endothelium. Fluid can be injected into the valve to alter the local pressure about the valve and force the electrodes into contact with the endothelium.

We claim: 
     
         1 . A neuromodulation device for use in a vessel having an endothelium and carrying body fluid with a fluid pressure, comprising:
 a) an elongate flexible outer catheter having a proximal end and distal end;   b) an inner catheter extending through said outer catheter, said inner catheter having proximal and distal ends and a lumen extending therethrough;   c) an expandable ablation valve having proximal and distal ends, said proximal end of said ablation valve coupled to said distal end of said outer catheter, and said distal end of said ablation valve coupled to said distal end of said inner catheter, said ablation valve having a circumference, and a plurality of electrodes displaced about said circumference,
 wherein longitudinal displacement of said inner catheter relative to said outer catheter in a first direction to cause said distal ends of said inner and outer catheters to move away from one another causes said ablation valve to move into a reduced diameter configuration, and longitudinal displacement of said inner and outer catheters in an opposite second direction causes to said ablation valve to radially expand into a expanded diameter open configuration; and 
   d) a conductor extending along said outer catheter, said conductor having a distal end electrically coupled to said electrodes of said ablation valve and a proximal end extended to a terminal for coupling to a RF generator.   
     
     
         2 . A neuromodulation device according to  claim 1 , wherein:
 in said reduced diameter, said electrodes are configured to be out of circumferential contact with the endothelium of the vessel, and in said expanded diameter, said electrodes are configured to be in contact with the endothelium of the vessel.   
     
     
         3 . A neuromodulation device according to  claim 1 , wherein:
 said ablation valve comprises a braid of filaments which cross over each other, and a layer bonded to the filaments defined by electrospun fibers, a proximal end of said braid of filaments radially collapsed and coupled to the distal end of said elongate introducer.   
     
     
         4 . A neuromodulation device according to  claim 3 , wherein:
 said electrospun fibers are provided as an outer layer over said filaments.   
     
     
         5 . A neuromodulation device according to  claim 3 , wherein:
 said filaments define at least a plurality of electrodes.   
     
     
         6 . A neuromodulation device according to  claim 5 , wherein:
 said filaments comprise insulated wires, and each said electrode is defined at a portion of said wire at which a portion of the insulation has been removed to expose an interior conductive metal of said wire.   
     
     
         7 . A neuromodulation device according to  claim 5 , wherein:
 said filaments include non-conductive filaments.   
     
     
         8 . A neuromodulation device according to  claim 5 , wherein:
 said device is bipolar.   
     
     
         9 . A neuromodulation device according to  claim 8 , wherein:
 said electrodes includes first and second electrically isolated sets of electrodes, and said conductor comprises first and two electrically isolated conductors, said first conductor electrically coupled to said first set of electrodes, and said second electrode coupled to said second set of electrodes.   
     
     
         10 . A neuromodulation device according to  claim 5 , wherein:
 said device is monopolar.   
     
     
         11 . A neuromodulation device according to  claim 1 , further comprising:
 said RF generator electrically coupled to said terminal.   
     
     
         12 . A neuromodulation system according to  claim 1 , wherein:
 advancement of said inner catheter relative to said outer catheter cause said distal ends of said inner and outer catheters to move away from one another and said valve into said reduced diameter configuration, and retraction of said inner catheter relative to said outer catheter causes said distal ends of said inner and outer catheters to move toward each other and said valve into said expanded diameter configuration.   
     
     
         13 . A neuromodulation system according to  claim 1 , wherein:
 longitudinal displacement of said inner and outer catheter modifies a duty cycle of said valve.   
     
     
         14 . A neuromodulation system according to  claim 1 , wherein:
 said outer catheter is sized for passage into a renal artery.   
     
     
         15 . A neuromodulation system according to  claim 1 , wherein:
 said valve comprises a braid layer and a fiber layer,   said braid layer including a plurality of elongate first filament and conductive second filaments, said second filaments each coated in an electrically insulative coating, a portion of said second filaments having said insulative coating removed therefrom to expose said conductive filaments within said insulative coating thus defining said plurality of electrodes, said   said first and second filaments each having a diameter of 0.025 mm to 0.127 mm, said first and second filaments having a proximal end, a distal end, and a length extending therebetween, said proximal ends secured relative to each other, said second filaments along said lengths distal of said proximal ends not bonded to each other such that said first and second filaments are movable relative to each other, said wherein in said second expanded configuration said first and second filaments cross one another at an angle of 100° to 150°, and said first filaments have a Young's modulus of elasticity greater than 100 MPa.   
     
     
         16 . A neuromodulation system according to  claim 15 , wherein:
 said fiber layer is radially displaced inward of said braid layer.