Evaluation of lower extremity bypass grafts with use of color duplex sonography

This article reviews the wide variety of graft procedures currently used to bypass lower extremity atherosclerotic disease and the means used to evaluate the grafts, which can be biologic, synthetic, or a combination of both. Graft failure rate can be as high as 10% within the first 10-14 days after placement, leveling off to approximately 2%-4% per year thereafter. Many of the early complications associated with graft placement can be attributed to technical errors in bypass construction. Although angiography remains the standard of reference for the evaluation of these grafts, duplex ultrasound is increasingly being utilized to document patency and detect suspected complications such as intimal flap, perigraft collection, arteriovenous fistula, pseudoaneurysm, and stenosis or occlusion. Sonography is able to clearly depict the echogenic walls of synthetic grafts and demonstrate whether blood flow wave-forms and blood flow velocity in both synthetic and biologic grafts are normal, thus enabling a more accurate diagnosis of suspected complications to be made. Familiarity with the normal sonographic appearance of these grafts, their anastomoses, potential complications, and the pitfalls in making a diagnosis is essential if an accurate diagnosis is to be made.