CAROTID ENDARTERECTOMY - TRIALS AND TRIBULATIONS

Since its introduction 40 years ago, the value of carotid endarterecto my has been controversial. In the early 1980s, several clinical trials were initiated to determine the efficacy of this operation in patient s with carotid stenoses who were either symptomatic or asymptomatic fo r retinal or hemispheric ischemia In 1991, interim results were publis hed for the North American Symptomatic Carotid Endarterectomy Trial (N ASCET) and the European Carotid Surgery Trial (ECST), both reporting e fficacy for surgery in patients with symptomatic carotid artery stenos is of greater than 70%. Subgroup analyses revealed variable risk group s. The Veterans Administration (VA) Symptomatic Trial (Cooperative Stu dies Program 309 of the Department of Veterans Affairs) terminated ear ly because of these results and its findings were consistent with the results of the larger trials. NASCET and ECST continue for symptomatic patients with carotid stenoses between 30% and 69%. The results of th ree trials in asymptomatic patients, the Mayo asymptomatic trial, the Carotid Artery Stenosis with Asymptomatic Narrowing: Operation Versus Aspirin trial, and the VA Asymptomatic Trial (Cooperative Studies Prot ocol 167 of the Department of Veterans Affairs), have been reported. N one showed a statistically significant benefit for surgery in the prev ention of stroke or death. However, none was sufficiently large to exc lude such a benefit. The large Asymptomatic Carotid Atherosclerosis St udy is in progress. Differences in the results and design of these tri als are discussed as are restrictions in the applicability of their re sults.