The data support the performance of a duplex scan either during surgery or before discharge from the hospital in addition to frequent surveillance for the first 6 months. Frequent surveillance is appropriate for lesions with less than 75% diameter reduction as long as they remain asymptomatic and without a significant reduction in the ankle-brachial index.

Duplex scan velocity measurements are valid predictors of impending graft thrombosis. A Vr of 3.5 or more and an MGV less than 50 cm/s are the best predictive measures. Repair of correctable graft lesions with a Vr of 3.5 or more, or inflow, outflow, or graft lesions associated with an MGV less than 50 cm/s are recommended. Grafts without detectable inflow, outflow, or graft stenoses, regardless of MGV, may be safely followed.