BACKGROUND: A heightened risk of stroke and death among octogenarians undergoing carotid artery stenting (CAS) has been reported. The multicenter Carotid Revascularization Endarterectomy vs. Stent Trial (CREST) supported by the National Institute of Neurological Disorders, National Institutes of Health, compares the efficacy of carotid endarterectomy (CEA) and CAS in an ongoing clinical trial. This effort also includes a "lead-in" phase of symptomatic (>50% stenosis) and asymptomatic (>70% stenosis) patients. The protocol calls for patients to receive aspirin and clopidogrel before and 30-days after CAS and to be examined by a study neurologist preprocedure, at 24-hours, and at 30-day. The occurrence of stroke and death was reviewed by an independent clinical events committee. METHODS: The association of age and periprocedural stroke and death was examined in 749 lead-in patients undergoing CAS (30.7% symptomatic, 69.3% asymptomatic). Patients were separated into four age categories: less than 60, 60 to 69, 70 to 79, and 80 years or older, and the proportion of patients with stroke and death during the 30-day periprocedural period was calculated for each category. RESULTS: An increasing proportion of patients suffered stroke and death with increasing age (P = .0006); 2 (1.7%) of 120 patients under age 60, 3 (1.3%) of 229 aged 60 to 69, 16 (5.3%) of 301 aged 70 to 79, and 12 (12.1%) of 99 patients aged 80 years and older. These increasingly high complication rates at older ages were not mediated by adjustment for symptomatic status, use of antiembolic devices, gender, percentage of carotid stenosis, or the presence of distal arterial tortuosity. CONCLUSIONS: Interim results from the lead-in phase of CREST show that the periprocedural risk of stroke and death after CAS increases with age in the course of a credentialing registry. This effect is not mediated by potential confounding factors. Randomized trial data are needed to compare the CAS versus CEA periprocedural risk of stroke and death by age. Pending results from randomized studies, care should be taken when CAS is performed in older patient populations.