Vascular grafts and method for preserving patency of the same

Abstract

This disclosure provides vascular grafts having a textured microporous surface capable of reducing perigraft fibrotic capsular formation, and a method of maintaining the patency of the vascular grafts.

1 . A vascular graft comprising:
 a blood-contacting layer formed of a first microporous biomaterial;   a nonporous intermediate layer; and   a tissue-interface layer having a textured microporous surface that contacts host tissue when implanted, the tissue-interface layer being formed of a second microporous biomaterial, wherein the textured microporous surface is capable of reducing fibrotic capsular formation.   
     
     
         2 . The vascular graft of  claim 1  wherein the textured microporous surface comprises peaks and valleys, where the height of the peaks is greater than 200 microns and less than 1000 microns, and wherein the tissue-interface layer comprises interconnected pores that are larger than 20 microns and smaller than 200 microns, and where adjacent pores have inter-pore openings of larger than 5 microns and smaller than 50 microns. 
     
     
         3 . The vascular graft of  claim 1 , wherein the blood-contacting layer comprises an open-pore porous biomaterial with substantially uniform pore diameter, where the pore diameter is larger than 20 microns and smaller than 50 microns, and wherein substantially all inter-pore connections between adjacent pores are larger than 5 microns and smaller than 30 microns. 
     
     
         4 . The vascular graft of  claim 1 , wherein the blood-contacting layer is formed of fluoropolymer. 
     
     
         5 . The vascular graft of  claim 4  wherein the blood-contacting layer is formed of expanded polytetrafluoroethylene. 
     
     
         6 . The vascular graft of  claim 1 , wherein the inner-blood-contacting layer is formed of polyethylene terephthalate. 
     
     
         7 . The vascular graft of  claim 1 , wherein the blood-contacting layer is formed of silicone or polyurethane elastomer. 
     
     
         8 . The vascular graft of  claim 1 , wherein the tissue-interface layer is formed of polytetrafluoroethylene or other fluoropolymer. 
     
     
         9 . The vascular graft of  claim 1 , wherein the tissue-interface layer is formed of polyethylene terephthalate or other polyester. 
     
     
         10 . The vascular graft of  claim 1 , wherein the intermediate layer is an adhesive layer containing fenestrations. 
     
     
         11 . A method of maintaining patency in the vascular graft of  claim 1 , the method comprising:
 pre-hydrating the vascular graft to remove any air in the first microporous biomaterial; and   implanting the vascular graft by directly connecting the vascular graft to a native blood vessel.   
     
     
         12 . The method of  claim 11  wherein pre-hydrating the vascular graft comprises soaking and subjecting the vascular graft to vacuum. 
     
     
         13 . The method of  claim 11  wherein maintaining patency comprises reducing stenosis of the vascular graft.