Outcomes after carotid artery stenting and endarterectomy in the medicare population

Background and Purpose- Carotid artery stenting (CAS) is an alternative to carotid endarterectomy (CEA) for stroke prevention. The value of this therapy relative to CEA remains uncertain. Methods- In 10 958 Medicare patients aged 66 years or older between 2004 and 2006, we analyzed in-hospital, 1-year stroke, myocardial infarction, and death rate outcomes and the effects of potential confounding variables. Results- CAS patients (87% were asymptomatic) had a higher baseline risk profile, including having a higher percentage of coronary and peripheral arterial disease, heart failure, and renal failure. In-hospital stroke rate (1.9% CAS versus 1.4% CEA; P=0.14) and mortality (CAS 0.9% versus 0.6% CEA; P=0.20) were similar. By 1 year, CAS patients had similar stroke rates (5.3% CAS versus 4.1% CEA; P=0.12) but higher all-cause mortality rates (9.9% CAS versus 6.1% CEA; P<0.001). Using Cox multivariable models, there was a similar stroke risk (hazard ratio, 1.28; 95% CI, 0.90-1.79) but CAS patients had a significantly higher mortality (HR, 1.32; 95% CI, 1.02-1.71). Sensitivity analyses suggested that unmeasured confounders could be responsible for the mortality difference. In multivariable analysis, stroke risk was highest in the patients symptomatic at the time of revascularization. Conclusions- CAS patients had a similar stroke risk but an increased mortality rate at 1 year compared with CEA patients, possibly related to the higher baseline risk profile in the CAS patient group.