Carotid Endarterectomy Trialists’ Collaboration. analysis of pooled data from the randomised controlled trials of endarterectomy for symptomatic carotid stenosis.

Rothwell PM,* Eliasziw M, Gutnikov SA, Fox AJ, Taylor DW, Mayberg MR, Warlow CP, Barnett HJ. Lancet 2003; 361:107–116
        There have been five randomized trials of endarterectomy for recently symptomatic carotid stenosis. They have shown that endarterectomy reduces risk of stroke in some patients with recently symptomatic internal carotid stenosis. However, investigators have made different recommendations about the degree of stenosis above which surgery is effective, partly because of differences between trials in the methods of measurement of stenosis. In this study, the authors pooled trial data and reassessed carotid angiograms to accurately assess the overall effect of surgery and to increase the power for secondary analyses. They obtained the data from the European Carotid Surgery Trial, North American Symptomatic Carotid Endarterectomy Trial, and Veterans Affairs Trial 309 from the original electronic data files. Outcome events were redefined, if necessary, to achieve comparability. Prerandomization carotid angiograms from ECST were remeasured by the method used in the other two trials. The authors found that risks of main outcomes in both treatment groups and the effects of surgery did not differ between trials. Data for 6,092 patients, with 35,000 patient-years of follow-up, were therefore pooled. Surgery increased the 5-year risk of ipsilateral ischemic stroke in patients with less than 30% stenosis (n = 1746; absolute risk reduction, −2.2%; P = .05), had no effect in patients with 30% to 49% stenosis (1,429; 3.2%, P = .6), was of marginal benefit in those with 50% to 69% stenosis (1,549; 4.6%; P = .04), and was highly beneficial in those with 70% stenosis or greater without near-occlusion (1,095; 16.0%; P < .001). There was a trend toward benefit from surgery in patients with near-occlusion at 2 years’ follow-up (262; 5.6%; P = .19), but no benefit at 5 years (−1.7%; P = .9). Reanalysis of the trials with the same measurements and definitions yielded highly consistent results. The authors conclude that surgery is of some benefit for patients with 50% to 69% symptomatic stenosis and highly beneficial for those with 70% symptomatic stenosis or greater but without near-occlusion. The benefit in patients with carotid near-occlusion is marginal in the short-term and uncertain in the long-term.—Valérie Biousse.
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