Ablation in the gastrointestinal tract to achieve hemostasis and eradicate lesions with a propensity for bleeding

Abstract

Devices and methods are provided for the ablation of regions of the digestive tract to achieve hemostasis and to eradicate chronically bleeding lesions as occur with gastric antral vascular ectasia (GAVE), portal hypertensive gastropathy (PHG), radiation proctopathy and colopathy, arteriovenous malformations, and angiodysplasia. Ablation is typically provided in a wide-field manner, and in conjunction with sufficient pressure to achieve coaptive coagulation. Ablation, as provided the invention, starts at the mucosa and penetrates deeper into the gastrointestinal wall in a controlled manner. Ablation control may be exerted by way of electrode design and size, energy density, power density, number of applications, pattern of applications, and pressure. Control may also be provided by a fractional ablation that ablates some tissue within a target region and leaves a portion substantially unaffected. Embodiments of the device include an ablational electrode array that spans 360 degrees and an array that spans an arc of less than 360 degrees.

What is claimed is: 
     
         1 . A system for ablation at a treatment site, comprising:
 an endoscope;   a support shaft extending at least partially through a working channel of the endoscope; and   an ablation device fixed to a distal end of the support shaft, the ablation device comprising a support and an ablational surface, wherein the ablation device is adapted to move back and forth between a stowed configuration and a deployed configuration.   
     
     
         2 . The system of  claim 1 , wherein the support is rollable such that it unrolls when pushed from the working channel and rolls when withdrawn into the working channel. 
     
     
         3 . The system of  claim 2 , wherein the support is adapted to present the ablational surface substantially parallel to a longitudinal axis of the endoscope when it unrolls. 
     
     
         4 . The system of  claim 1 , wherein in the stowed configuration the ablation device is adapted to be deployed through a working channel in the range of 2-5 mm. 
     
     
         5 . The system of  claim 1 , wherein the ablation device comprises collapsible shape memory ribs supporting electrodes. 
     
     
         6 . The system of  claim 1 , wherein the support comprises Nitinol. 
     
     
         7 . The system of  claim 1 , wherein the support has super-elastic shape memory properties. 
     
     
         8 . The system of  claim 7 , wherein the ablation device comprises a circuit backing on top of the support and radiofrequency (RF) energy delivery elements on top of the backing 
     
     
         9 . The system of  claim 7 , wherein the ablation device comprises a circuit backing on top of the support and copper traces on top of the backing. 
     
     
         10 . The system of  claim 1 , wherein a proximal portion of the support is tapered and has a laterally-curved bias when it is in a deployed configuration. 
     
     
         11 . The system of  claim 1 , wherein a proximal portion of the support is tapered and substantially flat when it is in a deployed configuration. 
     
     
         12 . The system of  claim 1 , wherein the support is adapted to expand to a preferred configuration when it is pushed from the working channel. 
     
     
         13 . The system of  claim 1 , wherein the support is adapted to roll around itself when it is withdrawn in the working channel. 
     
     
         14 . The system of  claim 1 , wherein the ablation device is deployable through the working channel and configured to project from the working channel to provide a broad field energy delivery surface. 
     
     
         15 . The system of  claim 1 , wherein the ablation device comprises a flexible portion proximal to the ablational surface to permit bending of the ablational surface. 
     
     
         16 . The system of  claim 1 , further comprising a torque transmission member adapted to transmit torque from a proximal end of the endoscope to the ablation device to rotate the device about a central axis of the endoscope. 
     
     
         17 . The system of  claim 16 , wherein the torque transmission member includes a key and a keyway adapted to resist relative movement between the endoscope and ablation device about the central axis. 
     
     
         18 . The system of  claim 17 , wherein the torque transmission member provides for 1-to-1 torque transmission. 
     
     
         19 . The system of  claim 1 , further comprising a torque transmission member including a first interlocking member and a second interlocking member configured for relative movement along a central axis of the endoscope. 
     
     
         20 . The system of  claim 1 , further comprising a torque transmission member adapted to provide for positioning of the ablation device either proximal or distal to the endoscope distal end in situ. 
     
     
         21 . An ablation device for ablation at a treatment site, comprising:
 a support shaft adapted to extend at least partially through a working channel of an endoscope; and   an ablation structure fixed to a distal end of the support shaft, the ablation structure comprising a support and an ablational surface, wherein the ablation structure is adapted to move back and forth between a stowed configuration and a deployed configuration with respect to the working channel of the endoscope.