Abstract 4144973: AI-enabled Nationwide Opportunistic Screening of Non-Contrast Chest CT: Association between Cardiac Calcium Score and All-cause Mortality/Cardiovascular Events in Taiwan

Background: Cardiac calcium, which includes coronary and extra-coronary calcification, is often incidentally found in chest CT scans performed for various reasons. Despite its prognostic value, manual quantification of cardiac calcium in non-gated chest CT images is labor-intensive. Goals: This retrospective study aims to perform automatic quantification and scoring of cardiac calcium in non-contrast-enhanced chest CTs. The objective is to determine associations between automatic calcium scoring and outcomes such as all-cause mortality, non-fatal myocardial infarction (MI), and non-fatal stroke. Methods: We conducted a nationwide cohort study using the Taiwan National Health Insurance Research Database (NHIRD) from 2016 to 2022. Patients under 20 years old, with a diagnosis of malignancy, or with outcome events before the CT acquisition were excluded. HeaortaNet 1.0, a validated AI model, was used for cardiac calcium scoring. Comorbidities were determined using ICD diagnostic codes for ≥2 consecutive outpatient visits within the year before the index date. Outcomes were censored at the first occurrence of mortality or relevant ICD codes for MI or stroke. Results: The retrospective cohort included 279,415 patients (56.37% male, mean age 60.31±16.54). All-cause mortality occurred in 12.82% of patients within a 3-year follow-up. The 3-year incidence rates of non-fatal MI and non-fatal stroke were 0.86% and 2.07%, respectively. Multivariate-adjusted Cox hazard ratios (95% confidence intervals) for any composite outcome were 1.51 (1.46-1.57), 2.09 (2.01-2.17), 2.63 (2.53-2.74), and 3.37 (3.24-3.50) for cardiac calcium scores of 1-100, 101-400, 401-1000, and >1000, compared to a score of 0. Adjusted Cox hazard ratios for all-cause mortality were 1.62 (1.56-1.69), 2.29 (2.19-2.39), 2.91 (2.78-3.04), and 3.80 (3.64-3.96) for scores of 1-100, 101-400, 401-1000, and >1000, compared to a score of 0. Conclusion: AI-enabled opportunistic screening of non-contrast chest CT for cardiac calcium scoring is associated with all-cause mortality and cardiovascular events. This is the first large-scale cohort study to use an AI model for comprehensive cardiac calcium screening.