Age modifies the relative risk of stenting versus endarterectomy for symptomatic carotid stenosis--a pooled analysis of EVA-3S, SPACE and ICSS.

BACKGROUND: Recent randomised controlled trials comparing carotid artery stenting (CAS) with endarterectomy (CEA) for the treatment of symptomatic carotid stenosis were not powered to investigate differences in risks in specific patient subgroups. We therefore performed a pooled analysis of individual patient data from the Symptomatic Severe Carotid Stenosis trial (EVA-3S), the Stent-Protected Angioplasty versus Carotid Endarterectomy trial (SPACE), and the International Carotid Stenting Study (ICSS).
METHODS: Individual data from all 3433 patients randomised and analysed in these trials were pooled and analysed with fixed-effect binomial regression models adjusted for source trial. The primary outcome event was any stroke or death.
RESULTS: In the first 120 days after randomisation (ITT analysis), the primary outcome event occurred in 153/1725 patients in the CAS group (8.9%) compared with 99/1708 patients in the CEA group (5.8%, risk ratio [RR] 1.53, 95% confidence interval [CI] 1.20-1.95, p = 0.0006; absolute risk difference 3.2, 95% CI 1.4-4.9). Age was the only subgroup variable which significantly modified the treatment effect: in patients <70 years old (the median age), the 120-day stroke or death risk was 5.8% in CAS and 5.7% in CEA (RR 1.00, 0.68-1.47); in patients 70 years or older, there was an estimated two-fold increase in risk with CAS over CEA (12.0% vs. 5.9%, RR 2.04, 1.48-2.82, interaction p = 0.0053).
INTERPRETATION: Endarterectomy was safer in the short-term than stenting, because of an increased risk of stroke associated with stenting in patients over the age of 70 years. Stenting should be avoided in older patients, but may be as safe as endarterectomy in younger patients. Determination of the efficacy and ultimate balance between the two procedures requires further data on long-term stroke recurrence.