EFFECT OF MULTILEVEL SEQUENTIAL STENOSIS ON LOWER-EXTREMITY ARTERIAL DUPLEX SCANNING

BACKGROUND: The sensitivity of lower extremity arterial duplex scanning in detecting a >50% stenosis may be decreased in extremities with multilevel sequential stenosis. PATIENTS AND METHODS: The results of lower extremity arterial duplex scanning of the common femoral, upper and lower superficial femoral, above- and below-knee popliteal arteries, and tibioperoneal trunk in 80 extremities of 44 patients were compared to those of arteriography, Thirty-one arterial segments in 27 extremities had a >50% stenosis, The stenoses were categorized as first order (first or only stenotic segment in the extremity n = 23) and second order (stenosis occurring distal to a >50% stenosis, n = 4, or occlusion, n = 4). RESULTS: The sensitivity, specificity, and positive predictive values of duplex scan detection of a >50% arterial stenosis or occlusion were 86%, 96%, and 67% for the common femoral artery; 95%, 98%, and 95% for the upper superficial femoral artery; 97%, 90%, and 88% for the lower superficial femoral artery; 84%, 90%, and 87% for the above-knee popliteal artery; 47%, 98%, and 90% for the below-knee popliteal artery; and 25%, 100%, and 100% for the tibioperoneal trunk, Duplex scanning detected 18 (78%) of the 23 first-order stenoses compared to only 1 (13%) of the 8 second-order stenoses in limbs with multilevel sequential disease (P <0.01), The peak systolic velocity at the stenotic site was significantly higher for first-order (mean +/- SD 168 +/- 54 cm/s) compared to second-order (38 +/- 13 cm/s) stenoses (P <0.00002). CONCLUSIONS: Duplex scanning was highly sensitive in detecting lower extremity first-order stenoses, Low peak systolic velocities at second-order stenoses of limbs with multilevel sequential disease significantly decreased the sensitivity of duplex scanning.