Abstract 17236: Coronary Artery Calcification Scoring Stratifies Risk of Sudden Cardiac Death: The CAC Consortium

Abstract

Introduction: Sudden cardiac death (SCD) commonly presents as the initial manifestation of coronary heart disease in the general population. Coronary artery calcium (CAC), a sub-clinical marker of atherosclerosis, is a strong predictor of cardiovascular events. We assessed the ability of CAC to stratify risk of SCD. Methods: We studied 66,636 adults from the CAC Consortium, a large multi-center cohort of asymptomatic patients free of clinical CVD at baseline. We categorized participants into 4 CAC score groups—CAC=0, CAC 1-99, CAC 100-399, and CAC≥400. The primary outcome was defined by identifying accepted International Classification of Diseases codes for SCD on official death certificates obtained for all deaths from the National Death Index. Predictive value of CAC for SCD was assessed using Cox proportional hazards regression models adjusted for age, sex and traditional risk factors. We performed standard area under receiver operating curve (AUC) analyses from fully adjusted logistic regression models, with and without CAC. All analyses were also repeated among participants aged 45-75 years. Results: Mean age of the study population was 54.4 years, and 33% were females and 89% were Whites. Over a mean follow up of 12.3±3.9 years, there were 211 SCD events. Participants with CAC=0 had lower absolute SCD rates compared to those with CAC≥400 (0.05 vs 1.28 per 1000 person-years, respectively). Increasing CAC scores (reference CAC=0) were associated with increasing SCD risk [CAC 100-399: HR (95% CI) 2.8(1.6-5.0), CAC≥400: 4.3(2.4-7.7)]. Addition of CAC to the fully adjusted model (vs without CAC) improved AUC for SCD among the whole study population (0.88 vs 0.86, P <0.001) and more so among 45-75 year-olds (0.82 vs 0.76, P <0.001). Conclusions: We demonstrate the predictive value of CAC for SCD. CAC could be a cost-effective risk-stratification tool that can be used to help identify individuals at high risk of SCD who could undergo additional screening and management.