AFTER SUCCESSFUL ENDARTERECTOMY FOR SYMPTOMATIC CAROTID STENOSIS, SHOULD ANY CONTRALATERAL BUT ASYMPTOMATIC CAROTID STENOSIS BE OPERATED ONAS WELL

We sought to determine whether there are any subgroups of patients who might benefit from endarterectomy of the asymptomatic carotid artery after successful operation for a symptomatic carotid stenosis. The inc idence and outcome of stroke in the asymptomatic carotid artery distri bution was prospectively studied in 966 patients who were entered into the European Carotid Surgery Trial and had a 30-99% asymptomatic caro tid stenosis. The patients had been randomized to either carotid endar terectomy (61%) or no endarterectomy of their symptomatic carotid sten osis. We reviewed the literature on the risks and efficacy of carotid endarterectomy and used these data in a decision analysis. The 5-year risk of stroke lasting more than 7 days in the asymptomatic carotid di stribution was 3.4%. Two independent prognostic factors were identifie d by means of Cox's proportional hazards regression with stepwise forw ard selection: the degree of asymptomatic carotid stenosis (30-69 vs. 70-99%) and hypertension. The 5-year-restricted and quality-adjusted l ife expectancy for a patient with both a severe (70-99%) asymptomatic carotid stenosis and hypertension, and therefore with the highest risk of asymptomatic carotid distribution stroke, was 4.14 life years for both conservative management and for endarterectomy. Plausible changes in the estimated risk of asymptomatic carotid distribution stroke, an d in the rate of complications from endarterectomy, increased the bene fit of endarterectomy. But, the maximal benefit was only 0.1 quality-a djusted life years or 5 weeks, even when endarterectomy was without ri sk. A separate regression model, with the degree of asymptomatic carot id stenosis as a continuous variable, suggested a possible benefit of endarterectomy for the few patients (n = 27, 3%) with an 80-99% asympt omatic carotid stenosis and hypertension. Until our results are refute d in other studies, there seems to be no firm indication for operation on the asymptomatic carotid artery in patients who have been successf ully operated for a symptomatic carotid stenosis, except within the co ntext of a randomized controlled trial.