Asymptomatic internal carotid artery occlusion (CO) presents a clinical dilemma, and presently, the natural history, stroke risk, and optimal management remain ill defined. This study compared outcomes, including neurovascular events (NVEs) and health care costs, between patients with CO and patients with asymptomatic carotid artery stenosis (CS).Methods
A prospectively maintained database was queried to identify patients with CO and CS with at least >50% carotid stenosis by duplex. We identified and reviewed 622 consecutive patients with asymptomatic carotid artery disease at one academic medical center between 2011 and 2013. Patients with CO (n = 97) were identified and propensity matched by age and gender in a 1:2 ratio with CS patients (n = 194) for further analyses. Univariate and multivariate models were used to analyze baseline characteristics, clinical variables, and 1-year follow-up data from the date of diagnosis. Multivariate analysis was performed by multiple linear regression modeling. Institutional Review Board approval was obtained.Results
Follow-up data were available for 99% of matched patients. CO patients were younger (72 vs 75 years; P < .01) and more likely male (67% vs 53%; P = .01) compared with CS patients. After propensity matching, baseline characteristics were similar between groups, with a trend toward higher use of statin therapy among patients with CO. Antiplatelet therapy was used in 79% of patients with CS and in 74% of patients with CO (P = .45). The rate of NVE among CO patients was higher than among CS patients at 1 year of follow-up (14% vs 7%; P = .03). Among those with NVE, neither antiplatelet therapy (64% vs 77%; P = .49) nor statin therapy (86% vs 77%; P = .58) appeared to have a significant effect. Health care costs ($14,361 vs $12,142; P = .44) and hospital admission rate (63% vs 71%; P = .18) were similar between groups. Not surprisingly, the rate of vascular procedures was higher in the CS group (55% vs 27%; P = .04).Conclusions
Patients with asymptomatic CO experience more NVEs compared with similar patients with moderately severe CS. Further study of preventative strategies, including intensity of medical therapy, is warranted.