[Analysis of the results of the main randomized trials on carotid endarterectomy for asymptomatic internal carotid stenosis].

The authors analyse the ACAS (1997-93) and ACST (1993-2003) trials, comparing the best medical therapy vs endarterectomy of an asymptomatic 60 % or more stenosis of the internal carotid artery. The ACAS trial does not reveal any benefit of surgery in preventing major stroke during follow-up (stroke rate 3.4% vs 6.02% in medical group, N.S.). Only by considering minor and major strokes together, a beneficial effect of carotid endarterectomy could be evidenced (5.9% stroke reduction at 5 years: 5.1% ipsilateral stroke at 5 years after surgery vs 11% stroke at 5 years under medical treatment). Indeed, following surgery, the stroke risk (ipsilateral) at 5 years attained 5,1% vs 11% following medical treatment of an asymptomatic internal carotid artery stenosis of 60-99%. The ACST trial, set up in 1993, aimed to assess the long-term result of carotid endarterectomy for asymptomatic 60-99% stenosis. Patients randomized for immediate surgery had a slightly more favorable outcome than those allocated to medical treatment. Absolute risk reduction of major stroke at 5 years was 2.5%. Overall, the benefit of operating an asymptomatic carotid artery stenosis is rather low (1% less stroke per year and less than 0.5% major stroke reduction per year). This positive result is obtained only if the operative stroke-death rate remains extremely low (<2.8%). The indication for operating asymptomatic carotid stenosis must be cautiously taken; age of the patient, degree of stenosis and surgeon's experience and results are to be considered.