Surgery Leads to Long-Term Reduction in Stroke Risk

Successful carotid endarterectomy (CEA) surgery halves the risk of having a stroke over the next 5 years, and benefit persists for at least 10 years, according to a new study.

Researchers at Oxford University (United Kingdom) and other institutions conducted a multicentre randomized trial of 3,120 asymptomatic patients from 126 centers in 30 countries between 1993 and 2003. The patients were allocated equally to immediate CEA or to indefinite deferral of any carotid procedure, and were followed up until death or for a median (among survivors) of nine years. The primary outcomes were perioperative mortality and morbidity--death or stroke within 30 days--and non-perioperative stroke.

The results showed that of the 1,560 patients allocated to immediate CEA, 89.7% were operated on while still asymptomatic; the perioperative risk of stroke or death within 30 days was 3%. Excluding perioperative events and nonstroke mortality, stroke risks at 5 years were 4.1% for immediate CEA, compared to 10% in the deferred CEA group, and 10.8% versus 16.9% (respectively) at 10 years. In all, 62 patients in the immediate CEA suffered a disabling or fatal stroke, compared to 104 patients who had a disabling or fatal stroke in the deferred CEA group; 37 versus 84 (respectively) other patients had a nondisabling stroke. When combining perioperative events and strokes, net risks between groups were 6.9% versus 10.9% at 5 years, and 13.4% versus 17.9% at 10 years. The total ratio of stroke incidence rates between groups was 0.54. The net benefits were significant both for those on lipid-lowering therapy and for those not, and both for men and for women up to 75 years of age at entry (although not for older patients). The study was published in the September 25, 2010, issue of the Lancet.

"This trial took more than 15 years to complete because we wanted to know about the long-term effects of surgery,” said lead author Prof. Alison Halliday, M.D., of Oxford University and the Asymptomatic Carotid Surgery Trial (ACST) collaborative group. "The definite benefits that we have found will be of practical value to doctors and patients deciding in the future whether to take the immediate risk of having such surgery.”

The researchers suggest that there is likely to be net benefit from operating on those in good health under 75 years old, as long as the surgical risks remain low. Among older patients, the immediate risk of CEA surgery may outweigh the long-term benefit.

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