Should duplex ultrasonography be performed for surveillance of femoropopliteal and femorotibial arterial prosthetic bypasses?

Duplex ultrasonography (DU) has been, shown to be beneficial for surveillan ce of lower extremity vein bypasses. However, DU as, part of surveillance p rogram for prosthetic grafts is not widely accepted. The purpose of this re port was to determine if DU could reliably detect failing prosthetic infrai nguinal arterial bypasses and if there were differences in predictability b etween femoropopliteal (FP) and femorotibial (FT) prosthetic grafts. Betwee n January 1992 and December 1997, 89 infrainguinal. grafts in 66 patients w ere entered into our postoperative prosthetic graft surveillance protocol, which included clinical evaluation, segmental pressures, pulse volume recor dings, and DU performed every 3 months. Patients with follow-up of less tha n 3 months were excluded unless the graft thrombosed. An abnormal DU consid ered predictive of graft failure included (1) peak systolic velocity (PSV) >300 cms/sec at inflow or outflow arteries, in the graft or at an anastomos is (unless an adjunctive arteriovenous fistula had been performed); (2) adj acent PSV ratio >3.0; (3) uniform PSVs <45 cms/sec; or (4) monophasic signa ls throughout the graft. DU was considered to have correctly diagnosed a fa iling graft if a stenosis >75% the luminal diameter of the graft, at an ana stomosis, or in an inflow/outflow artery was confirmed by operative or arte riographic, findings or if the graft thrombosed after an abnormal DU but be fore intervention. Our results support the routine use of DU as a part of a graft surveillance protocol for femorotibial, but not femoropopliteal, pro sthetic grafts.