The significance of aortoiliac atherosclerosis as assessed by Doppler ultrasound.

A simple, noninvasive method of assessing atherosclerotic aortoiliac obstruction is described using Doppler ultrasound with a concurrent electrocardiogram. The method is significantly more accurate than clinical examination. The pulse wave velocity profile at the common femoral artery is recorded with a nondirectional Doppler probe. The time delay from the R wave of the concurrent electrocardiogram to the ultrasound waveform peak and to a point half-way up the waveform upslope is measured. By evaluating the mean of ten such measurements at each point and then by taking the ratio of the former to the latter, a Proximal Damping Quotient (PDQ) may be derived. If the PDQ is greater than 1.4, significant proximal obstruction is probable. Conversely, a PDQ of less than 1.4 suggests a functionally clear aortoiliac segment. Any patient with a PDQ of less than 1.3 in whom reconstructive surgery is being correlated may thus be spared an aortogram and the affected limb may be investigated by femoral angiography alone. A low PDQ is supporting evidence of an adequate "run-in" to the distal segment when a distal arterial reconstruction is proposed. Similarly, if a femoro-femoral crossover graft is to be used, then significant aortoiliac atherosclerosis proximal to the donor femoral artery may be excluded without recourse to aortography.