MRC European Carotid Surgery Trial: interim results for symptomatic patients with severe (70-99%) or with mild (0-29%) carotid stenosis

The European Carotid Surgery Trial is a multicentre trial of carotid endarterectomy for patients who, after a carotid territory non-disabling ischaemic stroke, transient ischaemic attack, or retinal infarct, are found to have a stenotic lesion in the relevant (ipsilateral) carotid artery. Over the past 10 years 2518 patients have been randomised, and the mean follow-up is now almost 3 years among the 2200 thus far available for analysis of the incidence of strokes that lasted more than 7 days. For the patients with "moderate" (30-69%) stenosis on their prerandomisation angiogram the balance of surgical risk and eventual benefit remains uncertain, and full recruitment continues. For 374 patients with only "mild" (0-29%) stenosis there was little 3-year risk of ipsilateral ischaemic stroke, even in the absence of surgery, so any 3-year benefits of surgery were small, and were outweighed by its early risks. For 778 patients with "severe" (70-99%) stenosis, however, the risks of surgery were significantly outweighed by the later benefits: although 7·5% had a stroke (or died) within 30 days of surgery, during the next 3 years the risks of ipsilateral ischaemic stroke were (by life-table analysis) an extra 2·8% for surgery-allocated and 16·8% for control patients (a sixfold reduction, p