Utility of duplex ultrasound in detecting and grading de novo femoropopliteal lesions

Background: Digital subtraction angiography (DSA) is the gold standard for diagnosing lower extremity (LE) arterial lesions. However, duplex ultrasound (DUS) is a widely used, safe, and noninvasive method of detecting LE lesions. The purpose of this study was to establish DUS criteria for detecting and grading de novo stenotic lesions in the femoropopliteal arterial segment. Methods: A prospective database was established including all patients who underwent LE endovascular interventions between 2004 and 2009. Patients with de novo stenotic lesions in the femoropopliteal segment were selected. DUS and DSA data pairs <= 30 days apart were analyzed. Peak systolic velocity (PSV; cm/s), velocity ratio (Vr), and DSA stenosis were noted. Linear regression and receiver operator characteristic (ROC) curves were used. Results: Two hundred seventy-five lesions in 200 patients were analyzed. Indications were claudication (50.5%), rest pain (12.5%), and tissue loss (37.0%). Mean time interval between DUS and DSA was 24 days. Both PSV (R = .80, R-2 = .641; P < .001) and Vr (R = .73, R-2 = .546; P < .001) showed strong correlation with the degree of angiographic stenosis. ROC analysis showed that to detect >= 70% stenosis, a PSV of 200 cm/s had 89.2% sensitivity and 89.7% specificity, and a Vr of 2.0 had 88.7% sensitivity and 90.2% specificity. Similarly, to differentiate between <50% and >= 50% stenosis, PSV of 150 cm/s and Vr of 1.5 were highly specific and predictive. Combining PSV 200 cm/s and Vr 2.0 for >= 70% stenosis gave 79.0% sensitivity, 99.0% specificity, 99.0% positive predictive value, and 85.0% negative predictive value. Conclusion: DUS shows a strong agreement with angiography and has good accuracy in detecting femoropopliteal lesions. We propose DUS criteria of PSV 200 cm/s and Vr 2.0 to differentiate between <70% and >= 70% de novo stenosis in the femoropopliteal arterial segment. (J Vasc Surg 2011;54:1067-73.)