with woven vascular grafts in several configurations was completed the following materials although not exclusive were included a pga dacron u2122 80 20 low and high porosity 4 and 6 mm in diameter b pga copolymer having glycolic acid ester and trimethylene carbonate linkages 4 mm d gore tex a trademark of wil gore amp associates inc 4 8 and 10 mm the overall patency rate for pga containing grafts was substantially higher than controls 58 vs 41 bi and tri component vascular grafts made of biodegradable and non degradable fibers have been studied in the beagle observations carried out from u02dc 30 days to u02dc 7 months showed that as the absorbable component left the graft structure organized and oriented tissue invaded the graft approximating the location of the degraded material the tissue ingrowth appeared to mobilize as a neointima with the lumenal surface covered by cells strongly resembling endothelium the non degradable component exhibited dispersed fibers within a matrix of mature highly vascularized granulation tissue this rich blood supply persisted for the period of maximum observation the graft structures were provided in two diameters 4 and 8 mm id the former were studied as interpositional grafts in both carotids of the host the latter as interpositional grafts in the thoracic aorta the 4 mm grafts 40 60 mm in length were examined at 1 and 2 months and showed high degrees of patency the tissue reaction showed progressively.