Experimental studies on modified human ureter as an arterial substitution for reconstruction of small caliber vessels

Human ureters were experimentally employed as vascular biografts for small-caliber vessels. They were produced by tanning with polyepoxy compound or glutaraldehyde, and also were compared with saphenous veins tanned by polyepoxy compound and/or ready-made vascular graft of polytetrafluoroethylene (e-PTFE). These produced grafts, which had enough elasticity and excellent durability were successfully implanted to the carotid arteries in Japanese white rabbits. The grafts were sacrificed after 1 month observation. In this model there were no evidence of rejection, aneurysmal formation and/or infection. Polyepoxy compound fixed human ureter (n = 6), polyepoxy compound fixed saphenous vein (n = 6) and e-PTFE (n =3) showed good patency, but all glutaraldehyde fixed human ureters (n = 3) were completely occluded with severe intimal hyperplasia. Especially, polyepoxy compound fixed human ureter showed excellent patency as well as function, and the histological findings revealed monolayer endothelial cells covering the surface of the graft. No intimal hyperplasia was demonstrated at the anastomotic site. This study suggested that the polyepoxy compound fixed human ureter could serve as a satisfactory blood conduit of reconstruction for the small caliber vessels. Our preliminary data also suggests that longer observation up to 6 months in polyepoxy compound fixed human ureter graft and 18 months in polyepoxy compound fixed saphenous vein graft after surgery, arteriovenous shunt (A-V shunt), long bypass with a graft length of 2 to 5 cm), Y-graft model, sequential model and reinforcement graft by dacron cloth give good results.