Histologic images of the ePTFE valve leaflets explanted from a sheep 4 weeks after surgery.
A The surface of ePTFE leaflet was smooth, without obvious cell or tissue infiltration. The ePTFE membrane showed multilayered structure.(HE×400). B The surface of ePTFE on the sealing cuff revealed fibrous overgrowth, which attached loosely to the ePTFE membrane which itself had no obvious cell or tissue infiltration.(HE×200).