Abstract P667: Association of Number of Calcified Coronary Arteries and Cardiovascular Outcomes Stratified by Calcification Volume: The Multi-Ethnic Study of Atherosclerosis (MESA)

Background: Coronary artery calcium (CAC) is a risk factor for atherosclerotic cardiovascular disease (ASCVD). Data suggests number of vessels with CAC independently improves risk prediction but impact by CAC volume remains unknown. Methods: Using data from 3256 MESA participants with CAC>0 and clinical follow-up, we evaluated the association between number of arteries with CAC and risk for coronary heart disease (CHD), myocardial infarction (MI), and CVD events stratified by CAC volume (above/below median) using multivariable-adjusted Cox proportional hazards models. Results: Mean age was 63.3 years (SD 9.5) with 1363 (41.9%) women. There were 1079 (33%) with single-vessel, 822 (25%) with 2-vessel, and 1355 (42%) with 3-4 vessel CAC. Median CAC volume was 84.7 [IQR 24.5, 267.2] mm 3 . CAC in 3-4 vessels was independently associated with higher CHD risk ( Figure ) compared to 1-vessel (HR 2.01, 95% CI 1.1-3.6; p=0.018) and 2-vessels (HR 1.69, 95% CI 1.0-2.8; p=0.04) for lower CAC volumes, with similar findings for MI and CVD outcomes ( Table ). Conclusions: Number of arteries with CAC independently increases risk for ASCVD events only for those with lower CAC volumes.