Purpose: To evaluate the accuracy, predictive value, and observer agreement of the duplex ultrasound waveform at the common femoral artery as a marker of significant aortoiliac disease in a large group of consecutive patients who underwent a diagnostic workup for peripheral arterial disease in a vascular unit.
Methods: In 191 consecutive patients (381 aortoiliac segments), we classified the duplex ultrasound waveform at the common femoral artery as triphasic, biphasic, sharp monophasic, or poor monophasic. The waveforms were then compared with the findings of magnetic resonance angiography of the aortoiliac segment and peripheral runoff vessels. We calculated the diagnostic accuracy of the duplex waveform for detecting >50% obstructive disease of the aortoiliac segment and determined the observer agreement for classifying the duplex waveforms done by two independent observers.
Results: Magnetic resonance angiography showed obstruction in 152 (39.9%) of 381 aortoiliac segments in 191 patients. The presence of a poor monophasic waveform, encountered in 91 (24.3%) of 375 segments, was a reliable sign of significant aortoiliac disease, with a positive predictive value of 92%. Other waveforms were nondiagnostic for aortoiliac obstructive disease. The sharp monophasic waveform reliably predicted occlusive disease of the superficial femoral artery that was seen in 17 of 23 instances. There was good observer agreement for classifying duplex waveforms (kappa(w)= 0.85; 95% confidence interval, 0.80 to 0.89).
Conclusion: The poor monophasic duplex waveform at the common femoral artery is in itself an accurate marker of aortoiliac obstructive disease. Other waveforms are nondiagnostic for aortoiliac disease.