The current national criteria for carotid artery stenting overestimate its efficacy in patients who are symptomatic and at high risk

Background The Centers for Medicare and Medicaid Services (CMS) have established guidelines that outline patients who are considered "high risk" for complications after carotid endarterectomy (CEA) for which carotid artery stenting (CAS) may provide benefit. The validity of these high-risk criteria are yet unproven. In this study, we stratified patients who underwent CAS or CEA by CMS high-risk criteria and symptom status and examined their 30-day outcomes. Methods A nonrandomized, retrospective cohort study was performed by chart review of all patients undergoing CEA or CAS from January 1, 2005, to December 31, 2010, at our institution. Demographic data and data pertaining to the presence or absence of high-risk factors were collected. Patients were stratified using symptom status and high-risk status as variables, and 30-day adverse events (stroke, death, myocardial infarction [MI]) were compared. Results A total of 271 patients underwent CAS, with 30-day complication rates of stroke (3.0%), death (1.1%), MI (1.5%), stroke/death (3.7%), and stroke/death/MI (5.2%). A total of 830 patients underwent CEA with 30-day complication rates of stroke (2.0%), death (0.1%), MI (0.6%), stroke/death (1.9%), and stroke/death/MI (2.7%). Among symptomatic patients, physiologic high-risk status was associated with increased stroke/death (6 of 42 [14.3%] vs 2 of 74 [2.7%]; P P  = .14) in patients who underwent CAS vs CEA. Analysis of asymptomatic patients showed no differences between the two groups overall, except for a trend toward a higher rate of MI after CAS than after CEA (3 of 71 [4.2%] vs 0 of 108 [0.0%]; P  = .06) in those who were physiologically at high risk. Among symptomatic patients who underwent CAS, patients with physiologic and anatomic high-risk factors had a higher rate of stroke/death than non-high-risk patients (6 of 42 [14.3%] vs 0 of 24 [0.0%] and 5 of 31 [16.1%] vs 0 of 24 [0.0%], respectively; both P  ≤ .05). Conclusions Physiologic high-risk status was associated with increased stroke/death, whereas anatomic high-risk status showed a trend toward increased stroke/death in symptomatic patients undergoing CAS compared with non-high-risk patients undergoing CAS or physiologically high-risk patients undergoing CEA. Our results suggest that the current national criteria for CAS overestimate its efficacy in patients who are symptomatic and at high risk.