Abstract 9969: Number of Calcified Coronary Arteries and Prediction of Cardiovascular Outcomes: The Multi-Ethnic Study of Atherosclerosis

Abstract

Introduction: Current coronary artery calcium (CAC) scoring methods do not account for the number of vessels affected. We assessed the hypothesis that the number of vessels with CAC would be associated with higher risk for incident cardiovascular disease (CVD) outcomes, even after accounting for traditional risk factors, and that adding this metric to current risk scores would improve event prediction. Methods: We analyzed data from 3,255 MESA participants with baseline CAC and event follow-up. Cox proportional hazard regression analyses evaluated the association between number of affected vessels and incident myocardial infarction (MI), hard coronary artery disease (CHD), and hard CVD, adjusting for the ASCVD score and CAC volume and density. Area under the receiver operator curves (AUC) assessed event discrimination by adding number of vessels with CAC to current risk models. Results: At baseline [mean age 66 years (SD 9.6); 1,893 female (58%)], 1,086 participants (33%) had CAC in 1 vessel, 832 in 2 (26%), 987 in 3 (30%), and 385 in 4 (12%). Over a median of 15.5 years, 275 developed MI, 408 CHD, and 598 CVD. Multivariable-adjusted risk was higher with CAC in 3-4 vs 1 vessel for all outcomes (Table) and with 3-4 vs 2-vessels for CHD and CVD (HR 1.36, 95% CI 1.0-1.8 and HR 1.30, 95% CI 1.0-1.6). AUC increased after adding the number of vessels with CAC to the ASCVD score for MI (0.5992 to 0.6645, p=0.002), but not for CHD or CVD, and there was no significant increase for any endpoint when added to models already accounting for CAC volume and density. Conclusions: In a cohort free of baseline CVD, CAC had similar prevalence in 1, 2, and 3 vessels. After accounting for the ASCVD score and CAC volume and density, CAC in 3-4 vessels still conferred a significantly higher risk for adverse CVD outcomes compared to CAC in 1-2 vessels. Moreover, MI risk prediction was improved with adding the number of vessels with CAC to the ASCVD score, but not when also accounting for CAC volume and density.