Coronary CT angiography-derived epicardial coronary volume to left ventricular mass ratio associated with myocardial ischemic events in patients with type 2 diabetes mellitus.

BACKGROUND: Coronary volume to left ventricular mass ratio (V/M) derived from coronary computed tomography angiography (CCTA) may refine risk stratification for myocardial ischemic events in type 2 diabetes mellitus (T2DM). We aimed to evaluate its incremental prognostic value for myocardial ischemic events across obstructive and non-obstructive coronary artery disease (CAD). METHODS: This retrospective study included 306 patients with T2DM (59.1% male; mean age 62.3 ± 10.6 years), with no prior history of myocardial infarction (MI) or coronary revascularization, who underwent CCTA between January 2018 and 2019. CCTA parameters included luminal diameter stenosis, total plaque volume, computed tomography-derived fractional flow reserve (CT-FFR), and V/M. The composite endpoints encompassed all-cause mortality, nonfatal MI, unstable angina hospitalization, and late revascularization. Multivariable Cox proportional hazards regression models were employed to assess the independent prognostic value of V/M (per 1 mm³/g increment) beyond other CCTA parameters. Its incremental predictive value was quantified using the net reclassification improvement (NRI) and integrated discrimination improvement (IDI). RESULTS: Over 3.8-year median follow-up, 107 patients (35%) experienced ischemic events, including 5 deaths, 22 MIs, 62 angina hospitalizations, and 40 revascularizations. Obstructive CAD (hazard ratio [HR] = 1.821, 95% confidence interval [CI] 1.062–3.125; p = 0.029), total plaque volume > 750 mm3 (HR = 5.053, 95% CI 2.777–9.197; p < 0.001), CT-FFR ≤ 0.80 (HR = 1.881, 95% CI 1.063–3.365; p = 0.032), and V/M (HR = 0.899, 95% CI 0.865–0.935; p < 0.001) were identified as independent predictors. Incorporating V/M improved risk stratification (NRI = 0.173, 95% CI: 0.005–0.310, p = 0.044; IDI = 0.057, 95% CI: 0.019–0.112, p < 0.001). Subgroup analyses confirmed consistent prognostic performance of V/M in both obstructive (HR = 0.895, 95% CI 0.855–0.937; p < 0.001) and non-obstructive (HR = 0.887, 95% CI 0.814–0.967; p = 0.006) CAD. CONCLUSION: CCTA-derived V/M may serve as an independent predictor of myocardial ischemic events in patients with T2DM, particularly in those with non-obstructive CAD, offering incremental prognostic value beyond traditional CCTA parameters.