Screening algorithm for aortoiliac occlusive disease using duplex ultrasonography-acquired velocity spectra from the distal external iliac artery

Aortoiliac duplex scanning can be difficult to perform owing to the deep location of these vessels. We propose a new method to indirectly screen for aortoiliac disease by performing duplex examination of the distal external iliac artery (DEIA). After performing a preliminary study on 21 patients, the parameters of the Doppler waveform that best distinguish normal from diseased arteries were the presence or absence of reverse flow, peak systolic velocity, and resistance index. These values were used in a derived equation, with the value Y >= 0.78 predicting normal proximal inflow. We then studied 118 aortoiliac segments in 81 consecutive patients with arteriography and DEIA duplex ultrasonography. To predict moderate to severe stenosis, duplex ultrasonography had a sensitivity of 95.7%, a specificity of 84.1%, a positive predictive value of 80%, and a negative predictive value of 96.8%. Our formula thus predicted significant disease in 55 of the 118 aortoiliac segments (47%), with these segments needing further arteriographic evaluation. The other 63 limbs can be safely considered as having normal aortoiliac inflow. Our method accurately screens for aortoiliac disease and is excellent for predicting normal inflow. This information can be used to better plan the intraoperative diagnostic study and intervention.