Although the left atrioventricular coupling index (LACI) measured by Cardiac MRI is a strong predictor of CV events, the availability to CMR remains limited in clinical routine. Therefore, it would be useful to validate LACI assessment using other imaging methods such as computed tomography (CT). To investigate the prognostic value of the LACI assessed by cardiac CT, to predict the occurrence of CV death in consecutive patients without known CVD referred for CCTA.

Between 2010 and 2020, we conducted a single-center study with all consecutive patients without known CVD referred for CCTA. LACI was defined as the ratio of LA to LV end-diastolic volumes. The primary outcome was cardiovascular death. Cox regressions were used to evaluate the association of LACI with the primary outcome after adjustment for traditional risk factors and CCTA findings.

In 1444 patients (70±12years, 43% men), 92 (6.4%) patients experienced all-cause death, including 67 (4.3%) patients with cardiovascular death after a median (IQR) follow-up of 6.8 (5.9–9.1) years. After adjustment for risk factors and CCTA findings, LACI was positively associated with the occurrence of cardiovascular death (adjusted hazard ratio [HR]: 1.07 [95% CI: 1.05–1.09] per 1% increment, P<0.001), and all-cause death (adjusted HR, 1.05 [95% CI: 1.03–1.07] per 1% increment, P<0.001). After adjustment, a LACI≥25% showed the best improvement in model discrimination and reclassification above traditional risk factors and CCTA findings (C-statistic improvement: 0.27; NRI=0.826; IDI=0.209, all P<0.001; LR-test P<0.001).

LACI measured by CCTA is independently associated with cardiovascular death and all-cause death in patients without known CVD referred for CCTA, with an incremental prognostic value over traditional risk factors and CCTA findings. Incremental prognostic value of LACI using CT (Fig. 1).