Reduction of stent thrombogenicity

Abstract

A tissue graft construct and method for repairing the inner linings of damaged or diseased vertebrate vessels is described. The method comprises the steps of positioning a tissue graft construct within a blood vessel at a site in need of repair. The tissue graft construct comprises a stent ( 3 ) covered with submucosal tissue ( 4 ) wherein the stent ( 3 ) is formed for receiving the distal end of a catheter ( 1 ) having an inflatable balloon ( 2 ).

1 . A prosthetic device for repairing the inner linings of damaged or diseased vertebrate vessels, said device comprising 
 a cylindrical shaped expandable member having a luminal and exterior surface, wherein expansion of said member increases the circumference of said member; and    a layer of submucosal tissue fixed to the luminal or exterior surface of said member.    
     
     
         2 . The device of  claim 1  wherein the cylindrical shaped member is a vascular stent having a lumen sized for receiving a catheter.  
     
     
         3 . The device of  claim 1  wherein the submucosal tissue comprises intestinal submucosa delaminated from both the tunica muscularis and at least the luminal portion of the tunica mucosa of a warm-blooded vertebrate.  
     
     
         4 . The device of  claim 3  wherein the submucosal tissue covers both the exterior and the luminal surface of the stent.  
     
     
         5 . The device of  claim 4 , wherein said layer of submucosal tissue comprises a narrow sheet of submucosal tissue wrapped longitudinally about the luminal and exterior surface of the stent a plurality of times to form loops of submucosal tissue wherein each loop partially overlaps another loop of submucosal tissue.  
     
     
         6 . The device of  claim 4 , wherein the layer of submucosal tissue comprises a plurality of narrow sheets of submucosal tissue having a first end and a second opposite end wrapped longitudinally about the luminal and exterior surface of the stent, wherein the first and second opposite ends of each sheet of submucosal tissue are bonded together to form loops of submucosal tissue and wherein each loop of submucosal tissue partially overlaps another loop of submucosal tissue.  
     
     
         7 . The device of  claim 2  wherein the means for expanding the stent comprises a releasable spring mechanism that biases the prosthetic device to a minimal circumference.  
     
     
         8 . The device of  claim 2  wherein the layer of submucosal tissue comprises fluidized submucosal tissue coated onto the surface of the stents.  
     
     
         9 . The device of  claim 2  wherein the submucosal tissue covering the stent is provided with a plurality of slits that upon expansion of the expandable member provide fluid communication between the lumen of the stent and the exterior of the stent.  
     
     
         10 . A method for repairing the inner linings of damaged or diseased vertebrate vessels, said method comprising the steps of: 
 inserting a catheter into a vessel, wherein said catheter has a graft construct comprising submucosal tissue of a warm blooded vertebrate removably fixed to its distal end;    positioning the graft construct at a site within the vessel in need of repair;    biasing the graft construct against the luminal surface of the vessel to fix the graft construct to the luminal surface; and    removing the catheter.    
     
     
         11 . The method of  claim 10  wherein the catheter is a balloon-expandable catheter and the step of biasing the graft construct comprises inflating the balloon.  
     
     
         12 . The method of  claim 10  wherein graft construct further comprises a stent, and the submucosal tissue covers at least a portion of the exterior surface of the stent.  
     
     
         13 . The method of  claim 10  wherein the vessel is a blood vessel.  
     
     
         14 . An improved vascular stent for expanding obstructed vessels, said stent formed as an expandable tube having an exterior and luminal surface, the improvement comprising fixing a layer of submucosal tissue to the external surface of the stent.  
     
     
         15 . The improved vascular stent of  claim 14  further comprising a layer of submucosal tissue covering the luminal surface of the stent.  
     
     
         16 . The improved vascular stent of  claim 14  wherein a strip of submucosal tissue is wrapped longitudinally about the luminal and exterior surfaces of the stent a plurality of times to form loops of submucosal tissue and wherein each loop of submucosal tissue partially overlaps an adjacent loop of submucosal tissue.  
     
     
         17 . The improved vascular stent of  claim 14  wherein the layer of submucosal tissue is formed as a tube of submucosal tissue, wherein the tube is provided with a plurality of longitudinal slits.  
     
     
         18 . The improved vascular stent of  claim 17  wherein the longitudinal slits are approximately uniform in shape and are located equidistant from one another.  
     
     
         19 . The device of  claim 14 , wherein the layer of submucosal tissue comprises a pluraltiy of narrow sheets of submucosal tissue having a first end and a second opposite end wrapped longitudinally about the luminal and exterior surface of the stent, wherein the first and second opposite ends of each sheet of submucosal tissue are bonded together to form loops of submucosal tissue and wherein each loop of submucosal tissue overlaps with another loop of submucosal tissue.  
     
     
         20 . The improved vascular stent of  claim 14  wherein the stent comprises a wire that is coiled and shaped in the form of an incomplete tube, and the submucosal tissue is fixed to the stent by braiding a plurality of narrow sheets of submucosal tissue around the wire forming the stent.