Incidental coronary artery calcium (CAC) identified on routine nongated chest CT scans predicts future coronary heart disease (CHD) and cardiovascular disease (CVD) events with prognostic performance comparable to dedicated gated cardiac CT, supporting its incorporation into routine clinical practice for cardiovascular risk assessment. This study included 2,472 participants from the US Multi-Ethnic Study of Atherosclerosis (MESA) who had same-day gated and nongated chest CT scans and no prior history of CHD or CVD. Compared with participants with no CAC, those with moderate incidental CAC (Agatston score 101–299) had a 2.67-fold higher risk of CHD, while those with severe CAC (≥300) had a 5.22-fold higher risk. For CVD events, severe CAC was associated with a 2.89-fold higher risk, and moderate CAC was also associated with a significantly increased risk. CAC measurements from nongated and gated CT scans were highly correlated, and both approaches showed nearly identical predictive accuracy based on receiver operating characteristic curves, C-statistics, and Brier scores. These findings indicate that incidental CAC detected on nongated chest CT provides reliable prognostic information comparable to dedicated cardiac CT. Given the large number of nongated chest CT scans performed each year, incorporating CAC quantification into routine reporting offers a scalable strategy for personalized prevention. The findings are particularly relevant because the 2026 American College of Cardiology/American Heart Association dyslipidemia guidelines endorse the use of incidental CAC from nongated CT scans for atherosclerotic cardiovascular disease (ASCVD) risk stratification and to guide lipid-lowering therapy. Source: https://www.ahajournals.org/
