Infrainguinal vein graft surveillance: how and when

Graft surveillance has evolved over the last 15 years into a useful clinical tool designed to reduce the incidence of lower extremity vein bypass graft occlusion. Graft surveillance has not been shown to be efficacious in improving patency of prosthetic leg bypasses. However, the most common cause of infrainguinal vein graft occlusion is intrinsic graft stenosis. Vein graft lesions, or flow disturbances, develop in approximately one third of lower extremity autogenous vein grafts. These lesions frequently progress and ultimately are responsible for 60% to 80% of all vein graft occlusions. Surveillance protocols allow the vascular surgeon to identify such graft-threatening lesions and monitor them for progression, stabilization, or resolution based on measurements of peak systolic flow velocity, velocity ratio, end-diastolic velocity, and other simple hemodynamic parameters. There is a substantial body of clinical evidence, and a single prospective, randomized trial that suggest that lower extremity graft surveillance is clinically useful, cost effective, and likely improves long-term graft patency and limb salvage rates by 10% to 15%.