Comparison of Carotid Plaque Score and Coronary Artery Calcium Score for Predicting Cardiovascular Disease Events: The Multi‐Ethnic Study of Atherosclerosis

Background Coronary artery calcium (CAC) predicts coronary heart disease (CHD) events better than carotid wall plaque presence; however, differences in the utility of CAC burden and carotid plaque burden across the spectrum of cardiovascular disease (CVD) events is unknown. Methods and Results CVD, CHD and stroke/transient ischemic attack (TIA) events were evaluated prospectively in a multiethnic cohort without CVD at baseline. Carotid plaque score was determined by the number of ultrasound‐detected plaques in the common, bifurcation, and internal carotid artery segments. CAC was detected by computed tomography. Predictive values were compared using Cox proportional hazards models, C‐statistics, and net reclassification, adjusting for traditional CVD risk factors. At baseline, the 4955 participants were mean (SD) 61.6 (10.1) years old and 52.8% female; 48.9% had CAC >0 and 50.8% had at least 1 carotid plaque. After 11.3 (3.0) years of follow‐up, 709 CVD, 498 CHD, and 262 stroke/TIA events occurred. CAC score compared to carotid plaque score was a stronger predictor of CVD (hazard ratio [HR], 1.78; 95% CI, 1.16–1.98; P<0.001 vs HR, 1.27; 95% CI, 1.16–1.40; P<0.001) and CHD events (HR, 2.09; 95% CI, 1.84–2.38; P<0.001 vs HR, 1.35; 95% CI, 1.21–1.51; P<0.001). CAC score and carotid plaque score were weak predictors of stroke/TIA. CAC score had better reclassification statistics than carotid plaque score, except for stroke/TIA, which had similar predictive values. Conclusions CAC score improved prediction, discrimination, and reclassification of CVD and CHD better than carotid ultrasound measures, although prediction and discrimination were similar for stroke/TIA.