AI-derived left-to-right cardiac chamber volume ratios in coronary artery calcium scans strongly predict heart failure

Aims: The AI-CVD initiative seeks to extract actionable insights from coronary artery calcium (CAC) scans beyond the traditional CAC score. We previously demonstrated that AI-derived cardiac chamber volumes from CAC scans predict incident heart failure (HF). We aimed to evaluate whether left-to-right cardiac chamber volume ratios outperform chamber volumes in predicting HF. Methods and results: We used AI-CVD cardiac chambers volumetry data from CAC scans of 5732 asymptomatic Multi-Ethnic Study of Atherosclerosis (MESA) participants (age 62.2 ± 10.3 years; 47.7% male). Left-to-right ventricular (LV/RV), atrial (LA/RA), and left atrial-to-right ventricular (LA/RV) volume ratios were evaluated using multivariable Cox models and feature selection techniques. External validation was performed in the Framingham Heart Study Offspring (FHS-O) cohort (N = 1,052, age:58.3 ± 8.3, 42.9% male). During a median follow-up of 17.7 years in MESA, 369 participants (6.3%) developed HF. Elevated ratios (≥75th & ≥95th percentile) of LV/RV, LA/RA, and LA/RV were strongly associated with incident HF: hazard ratio (HR) for ≥95th percentile were 4.04 (95% CI: 2.89–5.65), 2.90 (95% CI: 2.07–4.06), and 2.61 (95% CI: 1.87–3.46), respectively. Among participants with normal LV sizes (interquartile-range), LV/RV ≥95th significantly predicted HF (HR: 2.34; 95% CI: 1.29–4.25). In FHS-O (median follow-up 14.4 years), 56 HF events (5.3%) occurred. LV/RV ≥75th percentile was significantly associated with HF (HR: 2.23; 95% CI: 1.16–4.30), whereas LA/RA was not (HR: 1.22; 95% CI: 0.65–2.29). Feature selection techniques identified LV/RV as the strongest predictor. Conclusion: In these two prospective cohorts, AI-derived LV/RV ratio from CAC scans strongly predicted HF. New clinical trials guided by these imaging biomarkers are warranted to establish their clinical utility.