Neoendothelial healing of modified EPTFE grafts.

Expanded polytetrafluoroethylene (EPTFE) grafts have poor neoendothelial healing characteristics and low patency rates after long-term implantation. The authors have shown that this is due to the low porosity of currently used EPTFE grafts (20-30 microns fibril length). The inner surface coated grafts made of long antithrombogenic material fibrils (40-60 microns) are desirable, especially for small diameter grafts. The authors have implanted these surface modified grafts (coated grafts) and noncoated grafts into abdominal arteries of rats and observed good patency rates, and the effects of surface modification of the grafts on stable endothelial tissue growth. The authors used four different kinds of grafts (fibril length, 20, 40, 60, and 90 microns, respectively) to investigate the effect of porosity. High porosity (long fibril length) grafts induce good neoendothelial healing and collagen production.