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, 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, and wherein the nonporous intermediate layer is between the blood-contacting layer and the tissue-interface layer.   
     
     
         2 . 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. 
     
     
         3 . The vascular graft of  claim 1 , wherein the blood-contacting layer is formed of fluoropolymer. 
     
     
         4 . The vascular graft of  claim 3  wherein the blood-contacting layer is formed of expanded polytetrafluoroethylene. 
     
     
         5 . The vascular graft of  claim 1 , wherein the inner-blood-contacting layer is formed of polyethylene terephthalate. 
     
     
         6 . The vascular graft of  claim 1 , wherein the blood-contacting layer is formed of silicone or polyurethane elastomer. 
     
     
         7 . The vascular graft of  claim 1 , wherein the tissue-interface layer is formed of polytetrafluoroethylene or other fluoropolymer. 
     
     
         8 . The vascular graft of  claim 1 , wherein the tissue-interface layer is formed of polyethylene terephthalate or other polyester. 
     
     
         9 . The vascular graft of  claim 1 , wherein the intermediate layer is an adhesive layer containing fenestrations. 
     
     
         10 . The vascular graft of  claim 1  wherein the intermediate layer is impermeable to blood and serum. 
     
     
         11 . A method of maintaining patency in the vascular graft of  claim 1 , the method comprising:
 implanting the vascular graft by directly connecting the vascular graft to a native blood vessel.   
     
     
         12 . The method of  claim 11  further comprising, prior to implanting, pre-hydrating the vascular graft to remove any air in the first microporous biomaterial. 
     
     
         13 . The method of  claim 12  wherein pre-hydrating the vascular graft comprises soaking and subjecting the vascular graft to vacuum. 
     
     
         14 . The method of  claim 11  wherein maintaining patency comprises reducing stenosis of the vascular graft. 
     
     
         15 . The method of  claim 11  wherein maintaining patency comprises reducing neointimal hyperplasia in the vascular graft.