Stents with improved fixation

Abstract

The present disclosure provides stents, particularly self-expanding stents, useful for the GI tract, and more particularly, useful for treating esophageal strictures. The stents provided herein include a medial region and proximal and distal cuffs having external diameters greater than the medial region diameter when the stent is in the deployed state. The medial region comprises an open weave wire construction. An elastomeric coating circumscribes the medial region, while the may be an extension of the wire construction or separate elements. Preferably, the cuffs have a textured surface for contact with the esophageal wall tissue to resist stent migration. The elastomer coated medial region provides a barrier to tissue ingrowth, and has an enhanced radial restoring force to maintain an open passageway in a body lumen. Optionally, the stent includes an exterior sheath with a surface pattern, to which the stent couples. A low durometer sleeve, between the stent and body lumen, axial positioning of the stent relative to the body lumen. Consequently, precision in stent placement is provided without tissue damage that could result if positioning motion occurred between the surface texture and the body lumen.

1 . A device for fixation in a body lumen, comprising:
 a tubular stent of open weave construction having a stent body having an axial length, the stent body comprising first and second ends and a medial region, the stent having a predetermined normal configuration and being radially compressible to a reduced-radius configuration; and   a continuous elastomeric film disposed axially along the stent, the continuous film circumscribing the stent over substantially the entirety of the axial length to define a barrier region of the stent to substantially prevent growth of tissue through the stent along the barrier region; and   wherein a portion of the barrier region of the stent comprises a surface texture for contact with the body lumen to provide a fixation region of the stent for positively fixing the stent within the body lumen at the treatment site, by radial expansion of the stent into a surface engagement with a tissue wall segment defining the body lumen, and   wherein the surface texture contains at least one class of hydrophobic regions on at least one spatial interaction dimension, and at least one class of hydrophilic regions on one or more other spatial interaction dimensions, wherein the ratio of any two spatial dimensions is greater than 2.   
     
     
         2 . The device of  claim 1  wherein:
 the stent is flexible, thereby assuming the reduced-radius configuration in response to the application of an external force, and tending to assume the normal configuration in the absence of the external force. 
 
     
     
         3 . The device of  claim 2  wherein the elastomeric film reinforces the stent along the barrier region. 
     
     
         4 . The device of  claim 3  wherein the film comprises silicone. 
     
     
         5 . The device of  claim 3 , wherein the fixation region of the stent exerts a lower restoring force in its return toward the normal configuration, relative to a non-textured region of the stent, upon removal of an external force. 
     
     
         6 . The device of  claim 5 , wherein the fixation region comprises an inflatable annulus at each end of the stent. 
     
     
         7 . The device of  claim 5 , wherein the fixation region comprises elastic polymeric torus at each end of the stent. 
     
     
         8 . The device of  claim 7  wherein the polymeric torus comprises a dry hydrogel. 
     
     
         9 . The device of  claim 1 , wherein the surface texture is disposed on a proximal cuff and a distal cuff. 
     
     
         10 . The device of  claim 9  wherein the surface texture is provided in a segmented pattern on the proximal and distal cuffs. 
     
     
         11 . The device of  claim 1 , wherein the barrier region has a diameter less than the diameter of the fixation region when the stent is in the deployed configuration. 
     
     
         12 . The device of  claim 1 , wherein the elastomeric film reinforces the stent along the barrier region. 
     
     
         13 . The device of  claim 1 , further comprising a removable and a low durometer delivery sleeve disposed on an outer surface of the stent, the sleeve following the outer surface, wherein the sleeve separates the body lumen from the fixation surface of the stent to allow positioning of the stent within the body lumen without engaging the fixation surface with the body lumen. 
     
     
         14 . A device for fixation in a body lumen, comprising:
 a flexible tubular stent having a predetermined normal configuration and being radially compressible to a reduced radius configuration in response to an external compression force; the stent radially expanding to the normal configuration in the absence of the external compression force, thereby fixing the stent within the body lumen; and   an elastically deformable reinforcement sleeve integral with the stent, disposed axially along the stent and substantially surrounding the stent to provide a reinforced region of the stent, said reinforced region requiring at least one minute to return to the normal configuration after removal of the external force;   wherein a portion of the stent is substantially free from the reinforcement sleeve and comprise a surface texture, the surface texture providing a fixation region of the stent, wherein the fixation region radially expands with less restoring force than the reinforced region upon removal of said external force;   wherein the fixation region comprises a surface texture comprising at least one class of hydrophobic regions on at least one spatial interaction dimension, and at least one class of hydrophilic regions on one or more other spatial interaction dimensions, wherein the ratio of any two spatial dimensions is greater than 2.   
     
     
         15 . The device of  claim 14 , wherein: the elastic deformable reinforcement sleeve comprises a polymeric film. 
     
     
         16 . The device of  claim 15 , wherein the polymeric film is a silicone film. 
     
     
         17 . The device of  claim 14 , wherein, the fixation region is disposed on proximal and distal cuffs, and the reinforced region comprises a medial region of the stent between the proximal and distal cuffs. 
     
     
         18 . The device of  claim 17 , wherein the proximal and distal cuffs have diameters larger than the diameter of the medial region when the stent is in the normal configuration. 
     
     
         19 . A device for fixation in a body lumen, comprising:
 a tubular elastic stent of open weave construction having a predetermined deployed configuration and being radially compressible to a reduced radius configuration in response to the application of an external force, the stent expanding to the deployed configuration in the absence of the external force; and   wherein a portion of the barrier region of the stent is of greater radius than other portions; and   wherein a separable and a low durometer, fixation sleeve is placed on the exterior surface of the stent, the sheath follows the outer surface of the stent when the stent is placed under compression, and follows the outer surface of the stent when it is deployed within a body lumen, and   wherein the fixation sleeve comprises an external surface having a surface texture disposed thereon, the surface texture comprising at least one class of hydrophobic regions on at least one spatial interaction dimension, and at least one class of hydrophilic regions on one or more other spatial interaction dimensions, wherein the ratio of any two spatial dimensions is greater than 2, and   wherein the fixation sleeve comprises an internal surface in contact with the stent.   
     
     
         20 . The device of  claim 19 , wherein the fixation sleeve and the stent are attached by at least one of a suture, a staple, or an adhesive. 
     
     
         21 .- 32 . (canceled)