Comparison and meta-analysis of randomized trials of endarterectomy for symptomatic carotid artery stenosis.

OBJECTIVE

Comparison and meta-analysis of randomized trials of carotid endarterectomy for symptomatic stenosis of the extracranial carotid artery.

BACKGROUND

Randomized trials (North American Symptomatic Carotid Endarterectomy Trial [NASCET], the European Carotid Surgery Trial [ECST], and the VA Cooperative Study [VACS]) each show that carotid endarterectomy improves outcomes in selected symptomatic patients with high-grade extracranial carotid artery stenosis. Direct comparisons among the studies have not been possible because of differing methodologies, endpoints, and formats of data reporting.

DESIGN/METHODS: Data for specified endpoints and corresponding person-years at risk were obtained for each trial. The rates of nonfatal stroke, nonfatal myocardial infarction, or death for surgically or medically treated patients in the perioperative period (30 days) and thereafter were compared (both including and excluding perioperative events) and then combined using meta-analytic techniques. Data from NASCET and ECST were also analyzed for differences in outcomes by sex.

RESULTS

Event rate estimates (with 95% confidence intervals [95% CI]) for the first 30 days (events per person-year, primarily nonfatal stroke) for medically treated patients were 0.44 (0.22 to 0.76) for NASCET, 0.15 (0.04 to 0.38) for ECST, and 0.27 (0.03 to 0.96) for VACS. For surgically treated patients, the corresponding rates (per person-year) were 0.78 (0.49 to 1.19), 0.63 (0.41 to 0.94), and 1.27 (0.58 to 2.43). Event rates per year after 30 days were higher for medically treated patients (0.20 [0.16 to 0.25] versus 0.08 [0.05 to 0.11] for NASCET; 0.12 [0.10 to 0.15] versus 0.07 [0.06 to 0.09] for ECST; and 0.15 [0.07 to 0.25] versus 0.07 [0.03 to 0.16] for VACS). There were no significant differences among the trials, with an overall benefit for surgical therapy (risk ratio estimate, RR = 0.67, 95% CI = 0.54 to 0.83). There were no significant sex-based differences between NASCET and ECST and the overall benefit was not significantly different for men and women (RR = 0.58, 95% CI = 0.45 to 0.74 for men; RR = 0.84, 95% CI = 0.57 to 1.25 for women).

CONCLUSIONS

Adjusting for primary endpoints and duration of follow-up, carotid endarterectomy has a similar benefit for symptomatic patients across trials and a similar benefit for men and women.