A systematic comparison of the risks of stroke and death due to carotid endarterectomy for symptomatic and asymptomatic stenosis.

BACKGROUND AND PURPOSE: There is some evidence that carotid endarterectomy reduces the risk of ipsilateral carotid territory ischemic stroke in patients with severe asymptomatic carotid stenosis. However, the benefit of endarterectomy is dependent on a low risk of stroke and/or death due to surgery. Whether the low operative risks reported in recent clinical trials and cited in recent guidelines are widely generalizable to clinical practice is unclear. Is endarterectomy for asymptomatic carotid stenosis really safer than surgery for recently symptomatic stenosis? METHODS: We performed a systematic review comparing the risks of stroke and death due to carotid endarterectomy, performed by the same surgeons or in the same institutions, for symptomatic and asymptomatic stenosis in studies published since 1980. RESULTS: Twenty-five studies fulfilled our criteria. Mortality within 30 days of endarterectomy was 1.31% for asymptomatic stenosis and 1.81% for symptomatic stenosis (odds ratio [OR], 0.69; 95% confidence interval [CI], 0.49 to 0.99). The risks of fatal stroke were 0.47% and 0.91%, respectively (OR, 0.57; 95% CI, 0.34 to 0.98). The overall risk of stroke and/or death was 3.35% for asymptomatic and 5.18% for symptomatic stenosis (OR, 0.61; 95% CI, 0.51 to 0.74). CONCLUSIONS: Mortality and the risk of stroke and/or death due to carotid endarterectomy are significantly lower for asymptomatic than symptomatic stenosis. These findings are consistent across virtually all studies and are likely to be widely generalizable.