Accuracy of carotid duplex examination to predict proximal and intrathoracic lesions.

Background: There is growing enthusiasm for doing carotid endarterectomy based on duplex examination alone, avoiding the risks of arteriography. Duplex cannot directly visualize proximal carotid or arch lesions. This study evaluates the prevalence of such lesions and the ability of duplex to predict their presence.

Methods: A retrospective review was conducted of 650 consecutive carotid duplex examinations followed by arteriography.

Results: Twenty-seven proximal lesions (10 occlusions and 17 stenoses) were predicted by duplex and confirmed by arteriography. One lesion was missed by duplex, for a sensitivity and specificity of 96% and 100%, respectively. The accuracy was 99%, and the negative predictive value was 99%. Prevalence of proximal lesions was 4% overall, but only 3% for stenotic lesions.

Conclusions: Proximal carotid and intrathoracic lesions are rare and can be predicted by duplex scan, thus avoiding arteriography. The absence of such lesions can be inferred with confidence from a negative duplex examination.