Does adding a delayed phase to cardiac computed tomography for coronary artery evaluation have prognostic value?

AIMS: Cardiac computed tomography (CCT) assesses coronary anatomy and enables delayed-phase imaging, including extracellular volume fraction (ECV) for diffuse myocardial fibrosis and late iodine enhancement (LIE) for focal myocardial replacement fibrosis. ECV and LIE reflect distinct pathological processes; combining these measures may improve subclinical myocardial injury detection. This study evaluated LIE and ECV in patients undergoing CCT for coronary artery assessment and examined their association with clinical outcomes. The primary outcome was a composite of all-cause death and unplanned cardiovascular hospitalizations; the secondary outcome was cardiovascular events, defined as cardiac death and unplanned cardiovascular hospitalization. METHODS AND RESULTS: We analysed 1207 consecutive patients who underwent CCT between January 2020 and September 2022. Patients were categorized into four groups based on the presence of LIE and elevated ECV. Associations with LIE and ECV, individually and combined, were assessed using Cox proportional hazards models. Of 1305 patients, 1207 met inclusion criteria and were followed for a mean of 26.0 ± 19.1 months. Kaplan-Meier analysis demonstrated a stepwise increase in risk across the four groups, with those having LIE and elevated ECV showing the highest cumulative incidence of composite events (log-rank P = 0.027). This group had increased risk for the composite outcome [hazard ratio (HR) 1.84, 95% confidence interval (CI) 1.22-2.79] and cardiovascular events (HR 2.67, 95% CI 1.32-5.41). CONCLUSION: In patients undergoing CCT for coronary artery evaluation, coexistence of LIE and elevated ECV is associated with higher risk of cardiovascular events and their assessment may provide synergistic prognostic value.