Evaluation of a microvascular prosthesis of microporous polytetrafluoroethylene in rats.

Polytetrafluoroethylene grafts were used as a microvascular prosthetic material in rats with a patency rate of 75 per cent. Immediate evaluation of the interface by scanning electron microscopy and histologic examination confirm the blood compatibility of the material, that is, limited platelet and erythrocytic activation or fibrin formation, or both. However, a longer evaluation period as great as three months fails to demonstrate the development of an endothelial lining which does not cross over the suture lines. Similarly, at this time, the immediate adjacent artery remains also devoid of typical endothelial structure. This result suggests that endothelial reconstitution, if present, even on normal substructures remains a delayed process.