Asymptomatic carotid stenosis: appropriateness of operative intervention.

The value of carotid artery surgery for symptomatic lesions causing TIA, stroke, or amaurosis fugax has been well documented. The role of prophylactic carotid endarterectomy in the treatment of asymptomatic stenosis remains controversial. Since a completed stroke with cerebral infarction is often the first clinical manifestation of a stenotic carotid artery lesion, an accurate estimate of the relative risk of medical or operative therapy is needed. Current data suggest that severe internal carotid stenosis of > 75% diameter reduction, deep or complex ulcerations, bilateral stenoses, and stenosis with contralateral occlusion represent a cumulative risk of stroke of 5% to 10% per year, often without antecedent TIA. Conversely, mild or moderate stenosis, small ulcers, fibromuscular dysplasia, and congenital kinking or coiling of the internal carotid carry a very low risk of stroke. The combined risk of stroke and death following prophylactic endarterectomy varies widely, with published rates from less than 1% to nearly 10%. The author suggests that carotid endarterectomy is warranted in good-risk patients with the most severe categories of asymptomatic lesions, when the surgeon's combined rates of stroke and death fall with the 1% to 2% range.