Rates and predictors of 5-year survival in a national cohort of asymptomatic elderly patients undergoing carotid revascularization

BACKGROUND: Current American Heart Association guidelines recommend carotid revascularization for asymptomatic patients on the basis of life expectancy. OBJECTIVE: To determine the rates and predictors of 5-year survival in elderly patients with asymptomatic carotid artery stenosis who underwent either carotid artery stent placement (CAS) or carotid endarterectomy (CEA). METHODS: The rates of 5-year survival were determined by use of Kaplan-Meier survival methods in a representative sample of fee-for-service Medicare beneficiaries 65 years of age who underwent CAS or CEA for asymptomatic carotid artery stenosis with postprocedural follow-up of 3.4±1.7 years. Cox proportional hazards analysis was used to assess the relative risk of all-cause mortality for patients in the presence of selected comorbidities, including ischemic heart disease, chronic renal failure, and atrial fibrillation, after adjustment for potential confounders such as age, sex, race/ethnicity, and procedure type. RESULTS: A total of 22 177 patients with asymptomatic carotid artery stenosis were treated with either CAS (n = 2144) or CEA (n = 20 033). The overall estimated 5-year survival rate (6SE) was 95.3±0.00149; it was 95.5% and 93.8% in patients treated with CEA and CAS, respectively. After adjustment for potential confounders, relative risk of allcause 5-year mortality was significantly higher among patients with atrial fibrillation (relative risk, 1.8; 95% confidence interval, 1.5-2.1) and those with chronic renal failure (relative risk, 2.1; 95% confidence interval, 1.7-2.6). CONCLUSION: Risks and benefits must be carefully weighed before carotid revascularization in elderly patients with asymptomatic carotid artery stenosis who have concurrent atrial fibrillation or chronic renal failure.