Diagnosis and management of patients with asymptomatic carotid artery bruit.

Asymptomatic lesions cause approximately 150,000 strokes in the U.S. each year. Lesions associated with significant risk of stroke include atherosclerotic plaques of the carotid bifurcation that compromise the lumen of the internal carotid artery by 75% or more, particularly if the plaque consists of soft material. A group of individuals with significant risk are those with atherosclerotic plaques containing large ulcerations. The risk of carotid endarterectomy is lower for patients with critical lesions that are asymptomatic than for patients with any other surgical indication, and averages a combined risk of morbidity and mortality of less than 1%. Two randomized, prospective studies are currently underway to compare the risks and the benefits of medical and of surgical management of this disease. Until the results of the randomized studies are available, prophylactic carotid endarterectomy for critical lesions is justified if the risk of surgery in the hands of an individual surgeon is less than 3% combined morbidity and mortality.