LAUSR

Introduction: Using pooled data from randomized trials of symptomatic patients assigned to carotid artery stenting (CAS) versus carotid endarterectomy (CEA), we have previously shown age to be an effect modifier, with increasing risk at older ages for CAS but not for CEA. To extend assessment of age as an effect modifier to the asymptomatic population, we combined the asymptomatic patients from CREST with the patients from ACT I. Methods: We analyzed data from 2544 subjects with >= 70% carotid stenosis randomized to CAS or CEA in addition to standard management of cardiovascular risk factors. CREST enrolled 1091 (548 CAS, 543 CEA) and ACT I enrolled 1453 (1089 CAS, 364 CEA) asymptomatic patients less than 80 years old (upper age eligibility in ACT I). We examined the impact of age on risk within CAS-treated and CEA-treated patients using Kaplan-Meier methods. Age was considered in three strata (< 65, 65 to 74, and 75+). The pre-specified, primary composite endpoint was stroke, myocardial infarction, or death during the periprocedural period or any ipsilateral stroke within 4 years after randomization. Results: For patients assigned to CAS, risk differed between the age strata (p <0.0001) where relative to those under age 65, there was no difference in risk for those aged 65 to 74 (HR = 1.3 ; 95% CI: 0.7, 2.3, p=0.38), but those aged 75+ were at substantially higher risk (HR = 2.9; 95% CI: 1.5, 5.5, p=0.001). In contrast, risk did not differ by age strata (p = 0.80) for those assigned to CEA. Conclusions: Age-related risk factors, e.g. carotid anatomy and underlying cerebral pathology, should be considered before selecting patients aged 75+ for CAS.