Asymptomatic tight stenosis of the internal carotid artery: long-term prognosis.

We followed 38 patients with a neck bruit due to symptomless internal carotid artery (ICA) stenosis greater than 90% for a mean period of 48 months. The annual rate of death or stroke was 7.2%. The cardiac death rate was 5.3% per year. Each year 1.7% of the patients had an unheralded ipsilateral infarct; after transient ischemic attacks, the proportion increased to 4.2%, and symptoms correlated with occlusion of the ICA. The low risk of unheralded ipsilateral infarct questions the usefulness of prophylactic endarterectomy. Diagnosis and treatment of risk factors and heart disease seem more important.