Abstract 11172: Heterogeneity in the Association Between the Presence of Coronary Artery Calcium and Cardiovascular Events: Multi-Ethnic Study of Atherosclerosis

Abstract

Introduction: Coronary artery calcium (CAC) has been widely recognized as an important predictor of cardiovascular disease (CVD). Given the finite resources, it is important to identify individuals who would receive the most benefit from detecting positive CAC by screening. However, the evidence is limited as to whether the burden of positive CAC on CVD differs by multi-dimensional individual characteristics. We aimed to investigate the heterogeneity in the association between positive CAC and incident CVD. Methods: This longitudinal cohort study included adults aged ≥45 years free of cardiovascular disease from the Multi-Ethnic Study of Atherosclerosis (MESA). After propensity score matching in a 1:1 ratio, we applied a machine-learning causal forest model to (i) evaluate the heterogeneity in the association between positive CAC and incident CVD and (ii) predict the increase in CVD risk at 10-year when CAC>0 (vs. CAC=0) at the individual level. We then compared the estimated increase in CVD risk when CAC>0 to the 10-year atherosclerotic CVD (ASCVD) risk calculated by the 2013 ACC/AHA pooled cohort equations. Results: Across 3,348 adults in our propensity score-matched analysis, our causal forest model showed heterogeneity in the association between CAC>0 and incident CVD. We found a dose-response relationship of the estimated increase in CVD risk when CAC>0 with higher calculated 10-year ASCVD risk ( Figure ). Even among 1,413 adults with low/borderline ASCVD risk, 689 (49.4%) showed ≥7.5% increase in CVD risk when CAC>0; these individuals were more likely to be male, non-Hispanic Black or Hispanic, less educated, never smokers, and have unfavorable CVD risk factors than others. Conclusion: The increases in CVD risk when CAC>0 were heterogeneous across individuals, and nearly half of people with low/borderline calculated ASCVD risk showed a large increase in CVD risk when CAC>0, highlighting the need for CAC screening among such low-risk individuals.