[en] It is important to establish clear definitions concerning carotid artery disease, a topic that recently regained widespread interest in medical literature. Therefore, we summarize a paper of Rothwell and Barnett, recently published in the Lancet 2003 (1). In their analysis, the data of three randomized trials, comparing carotid endarterectomy to optimal medical therapy alone for a symptomatic internal carotid artery stenosis, were pooled after standardization of the measurement of the degree of stenosis and redefinition of the outcome events, to achieve comparability of the results of each trial. This analysis concerns 6092 patients with 35,000 patient-years of follow-up. Surgery offers a marginal benefit for patients with a moderate (50-69%) symptomatic carotid artery stenosis (absolute risk reduction of 4.6% for subsequent ipsilateral stroke at 5 years). Surgery is highly beneficial for patients with a symptomatic 70-99% stenosis (absolute risk reduction of 16% for ipsilateral stroke at 5 years). The benefit is uncertain for a symptomatic "near occlusion" (99% with retarded opacification of the distal internal carotid artery): absolute risk reduction of -1.7% for ipsilateral stroke at 5 years).