Aortoiliac occlusive disease: a simple noninvasive method to determine significance

This study was undertaken to develop a simple, noninvasive method for determining the hemodynamic significance of aortoiliac occlusive disease. In 14 dogs, 10-MHz Doppler recordings from the aorta and femoral arteries were made under normal (control) conditions and after construction of subcritical and critical iliac artery stenoses as documented by the papaverine test. The femoral waveforms obtained were analyzed for configuration (tri-, bi-, or monophasic) and pulsatility index. A ratio of time from ECG QRS peak to peak femoral flow divided by the time to peak aortic flow (TRFA) was calculated as was a ratio of the maximum rate of rise of the femoral Doppler signal to the aortic Doppler signal (MRRFA). These parameters were compared using Fisher's exact test and analysis of variance. TRFA and MRRFA accurately categorized the degree of iliac occlusive disease into statistically distinct groups. A TRFA less than 1.10 or a MRRFA greater than 0.70 identified a normal artery. MRRFA distinguished normal aortoiliac arteries from those with subcritical stenosis with a sensitivity of 0.93, a specificity of 1.00, and an accuracy of 0.96. TRFA distinguished normal aortoiliac arteries from those with a subcritical stenosis with a sensitivity of 0.86, a specificity of 0.86, and an accuracy of 0.86. Both TRFA and MRRFA separated normal aortoiliac arteries from those with a critical stenosis with a sensitivity of 1.00, a specificity of 1.00, and an accuracy of 1.00. The femoral Doppler waveform configuration and pulsatility index could not accurately categorize these differences (P = 0.100).