Is biventricular vascular coupling a better indicator of ventriculo-ventricular interaction in congenital heart disease?

Background: Ventriculo-ventricular interactions are known to exist, though not well quantified. We hypothesised that the ventricular–vascular coupling ratio assessed by cardiovascular MRI would provide insight into this relationship. We also sought to compare MRI-derived ventricular–vascular coupling ratio to echocardiography and patient outcomes. Methods: Children with cardiac disease and biventricular physiology were included. Sanz’s and Bullet methods were used to calculate ventricular–vascular coupling ratio by MRI and echocardiography, respectively. Subgroup analysis was performed for right and left heart diseases. Univariate and multivariate regressions were performed to determine associations with outcomes. Results: A total of 55 patients (age 14.3 ± 2.5 years) were included. Biventricular ventricular–vascular coupling ratio by MRI correlated with each other (r = 0.41; p = 0.003), with respect to ventricle’s ejection fraction (r = −0.76 to −0.88; p < 0.001) and other ventricle’s ejection fraction (r = −0.42 to −0.47; p < 0.01). However, biventricular ejection fraction had only weak correlation with each other (r = 0.31; p = 0.02). Echo underestimated ventricular–vascular coupling ratio for the left ventricle (p < 0.001) with modest correlation to MRI-derived ventricular–vascular coupling ratio (r = 0.43; p = 0.002). There seems to be a weak correlation between uncoupled right ventricular–vascular coupling ratio with the need for intervention and performance on exercise testing (r = 0.33; p = 0.02). Conclusion: MRI-derived biventricular ventricular–vascular coupling ratio provides a better estimate of ventriculo-ventricular interaction in children and adolescents with CHD. These associations are stronger than traditional parameters and applicable to right and left heart conditions.