Randomized clinical trial results define operative indications in symptomatic and asymptomatic carotid endarterectomy patients.

Randomized clinical trials on the efficacy of carotid endarterectomy have assisted in the selection of patients for operative intervention. Three such trials involving symptomatic carotid stenosis have confirmed the value of endarterectomy in patients with stenoses 70% or greater. Patients with recent transient ischemic attack or nondisabling stroke should be referred for noninvasive testing. If the patient's stenosis exceeds a threshold level (50% to 70% diameter-reducing lesion), arteriography should be performed and prompt endarterectomy scheduled, rather than antiplatelet therapy, as the primary means of treatment. Furthermore, the results of one clinical trial on asymptomatic stenosis have demonstrated benefits for operative intervention in reducing neurologic events (transient ischemic attack plus stroke). These data require additional confirmation in the analysis of stroke alone, which should be available within the next year from another clinical trial. These trials help to define indications for operation, and the thorough knowledge of their results has become essential to our practices.