SURVEILLANCE OF INFRAINGUINAL VEIN GRAFTS WITH DUPLEX SONOGRAPHY

This review considers the relative roles of traditional noninvasive va scular tests and conventional duplex and color flow Doppler sonography in the surveillance of infrainguinal autologous vein grafts. The purp ose of surveillance is to identify significant anatomic or flow abnorm alities that predispose to thrombosis, but can be repaired before graf t thrombosis occurs. Although a few authors believe that serial measur ements of the ankle-brachial index and other noninvasive vascular test s can serve as the primary method of surveillance for infrainguinal gr afts, most authors do not concur. After the first postoperative month, stenosis caused by intimal hyperplasia is the most common cause of gr aft failure, usually occurring within 18 months after placement. Duple x sonography is both highly sensitive and specific for detection of su ch stenoses. Specific duplex sonographic criteria have been establishe d for grading of stenoses and for the diagnosis and classification of arteriovenous fistulas. A large body of evidence suggests that graft t hrombosis can occur without prior warning symptoms and that long-term graft patency improves if the asymptomatic lesions detected with duple x sonography are repaired before symptoms develop.