Evaluation of carotid bifurcation disease: the role of common carotid artery velocity patterns.

We evaluated duplex ultrasonographic velocity patterns from the common carotid artery in 156 patients with arteriographically verified internal carotid artery disease. Flow to zero during diastole in the common carotid was found in three groups of patients: (1) those with flow to zero in both common carotids not related to disease of the carotid bulb; (2) those with a tight (90% to 99%) stenosis in the internal carotid; and (3) those with total occlusion of the internal carotid. Although such flow to zero is commonly observed with total occlusion of the internal carotid artery, it may also be seen with high-grade stenosis. Thus, when found, it is essential to ascertain if flow is indeed present in the internal carotid artery; understanding changes in velocity patterns of the common carotid has improved our overall accuracy in detecting extracranial carotid artery disease.