Optimal Ultrasound Criteria for Grading Stenosis of the Superficial Femoral Artery.

This retrospective study determined the duplex ultrasound scanning criteria for detecting 50%-69% and 70%-99% stenosis of the superficial femoral artery (SFA). Examinations of 278 limbs in 185 patients with peripheral arterial disease were performed. Duplex ultrasound scanning was used to measure the diameter of the vascular lumen, the peak systolic velocity (PSV) at the stenotic segment of the SFA (PSVst), the segment proximal to the stenosis (PSVpro) and the popliteal artery (PSVpop, distal to the stenosis). The ratios PSVst/PSVpro and PSVst/PSVpop were calculated. Receiver operator characteristic curves were plotted, with digital subtraction angiography as the reference. PSVst and PSVst/PSVpop had the highest diagnostic value for stenosis. Cut-off thresholds were: for 50%-69% stenosis, PSVst ≥ 210 cm/s, PSVst/PSVpop ≥ 2.5, with PSVst the better parameter; for 70%-99% stenosis, PSVst ≥ 275 cm/s, PSVst/PSVpop ≥ 4.0, with PSVst/PSVpop superior. PSVst/PSVpop may be a better parameter than PSVst/PSVpro for diagnosing SFA stenosis.