Determination of the hemodynamic significance of iliac artery stenosis by noninvasive Doppler ultrasonography.

The ability of common femoral artery Doppler blood flow velocity waveforms to predict the hemodynamic significance of aortoiliac artery stenosis was determined by comparing intraoperative pressure gradient and flow measurements with two noninvasive nondimensional Doppler velocity waveform indices. The Doppler velocity waveforms of 63 common femoral arteries were recorded preoperatively, and iliac artery pressure gradients and blood flows were measured intraoperatively in 48 nonoccluded arterial segments. The mean iliac artery pressure gradient at double resting flow was calculated for comparisons between patients. Two Nondimensional Doppler velocity waveform indices were calculated: the minimum to maximum velocity amplitude ratio and the maximum to mean velocity amplitude ratio. Both Doppler velocity ratios successfully distinguish arteries with minimal or no hemodynamically significant stenosis from arteries with hemodynamically significant stenosis (mean pressure gradient at double resting flow resting flow greater than 6 mm Hg). A minimum to maximum Doppler velocity ratio of less than 0.185 or a maximum to mean Doppler velocity ratio greater than 2.10 indicates hemodynamically significant aortoiliac stenosis. Superficial femoral artery occlusion was indistinguishable from mild iliac stenosis by the two Doppler velocity waveform ratios but was clearly distinct from significant iliac stenosis.