Apparatus and methods for renal denervation ablation

Abstract

A catheter device for renal denervation ablation includes a flexible catheter shaft having an electrically insulating expandable member in its distal portion with at least one electrode located proximal to the member, at least one electrode located distal to the member, and with openings in the distal shaft with at least one opening proximal to the proximal electrode and one opening distal to the distal electrode of said electrode pair, said openings connected through an inner lumen in the catheter that provides a path for blood to flow through the expandable member. In one embodiment, the device comprises a flexible catheter shaft with a multiplicity of recessed paired electrodes disposed in recessed spaces in its distal portion, such that an electrically conducting portion of each electrode is exposed to the exterior of the catheter within a recessed space, and with an electrical insulator separating the electrodes of each pair.

1 . An apparatus, comprising:
 a flexible catheter shaft having an electrically insulating expandable member coupled thereto such that the expandable member surrounds a portion of the catheter shaft, the portion of the catheter shaft defines a lumen, a surface of the catheter shaft defining a first opening and a second opening, the first opening and the second opening each in fluid communication with the lumen, the expandable member disposed between the first opening and the second opening to establish a pathway through the expandable member via the lumen; and   at least one electrode pair, the electrode pair including a first electrode and a second electrode, the first electrode coupled to the catheter shaft between the first opening and the expandable member, the second electrode coupled to the catheter shaft between the second opening and the expandable member.   
     
     
         2 . The apparatus of  claim 1 , further comprising:
 a first insulated electrical lead coupled to the first electrode, the first electrical lead disposed at least partially within the catheter shaft; and   a second insulated electrical lead coupled to the second electrode, the second electrical lead disposed at least partially within the catheter shaft.   
     
     
         3 . The apparatus of  claim 2 , wherein the first electrical lead has an insulation layer having a thickness and a dielectric strength such that the first electrical lead is configured to withstand a voltage of at least 500 Volts without dielectric breakdown. 
     
     
         4 . The apparatus of  claim 1 , wherein:
 the lumen is a first lumen;   the expandable member is configured to be filled with a fluid to move between a collapsed configuration and an expanded configuration; and   the portion of the catheter shaft defines a second lumen in fluid communication with the expandable member, the second lumen fluidically isolated from the first lumen.   
     
     
         5 . The apparatus of  claim 1 , where the electrode pair includes rings with ring widths in the range between approximately 1 mm and approximately 6 mm. 
     
     
         6 . The apparatus of  claim 1 , where the expandable member has an expanded diameter in the range between approximately 2 mm and approximately 6 mm. 
     
     
         7 . The apparatus of  claim 1 , where the electrodes in the pair of electrodes have a nearest edge-to-edge separation distance in the range between approximately 3 mm and approximately 25 mm. 
     
     
         8 . The apparatus of  claim 1 , where the expandable member material comprises polyurethane. 
     
     
         9 . A system for irreversible electroporation renal denervation ablation comprising:
 a. a voltage pulse generator unit,   b. a controller unit connected to the pulse generator unit for triggering the pulses of the pulse generator unit, and which is capable of applying voltage pulses to a multiplicity of electrodes on at least one medical device connected to it,   c. said medical device having an electrically insulating inflatable balloon coupled to its distal portion such that the catheter shaft passes through the balloon, and having at least one electrode on the shaft located proximal to the balloon and at least one electrode on the shaft located distal to the balloon, and having an inner lumen in the catheter with at least a pair of openings to the exterior surface of the catheter, said lumen providing a path for blood to flow through the balloon, and   d. a user interface for a user to interact with the system.   
     
     
         10 . The system of  claim 9 , where the voltage pulses have an amplitude of at least 500 Volts. 
     
     
         11 . The system of  claim 9 , where the voltage pulses are applied in the form of a train of multiple pulses, each pulse having a pulse width of at least 10 nanoseconds. 
     
     
         12 . The system of  claim 9 , where the openings from the exterior surface of the catheter to the inner lumen in the catheter are disposed with at least one opening located proximal to an electrode proximal to the balloon, and with at least one opening located distal to an electrode distal to the balloon. 
     
     
         13 . The system of  claim 9 , where the electrodes of the medical device comprise a biocompatible metal. 
     
     
         14 . The system of  claim 9 , where an insulated electrical lead connects to each electrode of the medical device, the insulated lead having an insulation layer with a thickness and a dielectric strength capable of withstanding a voltage of at least 2000 Volts without dielectric breakdown. 
     
     
         15 . The system of  claim 9 , where the medical device is a flexible catheter with a shaft constructed from a material comprising one or more of Teflon, polyurethane, Nylon, PEEK and polyethylene. 
     
     
         16 . The system of  claim 9 , where the inflatable balloon material comprises polyurethane. 
     
     
         17 . The system of  claim 9 , where the electrodes on the medical device are rings with ring widths in the range between approximately 1 mm and approximately 6 mm. 
     
     
         18 . The system of  claim 9 , where the controller unit records impedance data from at least a pair of the electrodes of the medical device connected to it. 
     
     
         19 . The system of  claim 9 , where the user interface comprises a push-button interface for the user-driven application of voltage pulse trains for ablation. 
     
     
         20 . A method, comprising:
 inserting a distal end portion of a catheter assembly into a renal artery, the distal end portion of the catheter assembly including an electrically insulating expandable member, the distal end portion of the catheter assembly defining a lumen, a surface of the catheter assembly defining a first opening and a second opening, the first opening and the second opening each in fluid communication with the lumen, the expandable member disposed between the first opening and the second opening;   transitioning the expandable member from a collapsed configuration to an expanded configuration to establish a blood flow through the lumen; and   applying a voltage pulse train to an electrode pair, the electrode pair including a first electrode and a second electrode, the first electrode coupled to the catheter assembly between the first opening and the expandable member, the second electrode coupled to the catheter assembly between the second opening and the expandable member.