Ventriculo-arterial coupling in pulmonary regurgitation following transannular patch repair of pulmonary stenosis

Pulmonary regurgitation is a common consequence following the repair of tetralogy of Fallot and can lead to heart failure. Early detection of right ventricular dysfunction remains challenging, and current clinical markers have limited predictive value to identify which patients are at risk for heart failure and require interventions. This study aimed to investigate the potential of ventriculo-arterial coupling as a marker of early right ventricular dysfunction in a porcine model of chronic pulmonary regurgitation following transannular patch repair of neonatal pulmonary stenosis. Neonatal swine were subjected to pulmonary artery banding for 1 month to induce RV pressure overload, followed by transannular patch repair (rTAP, n=10) to create chronic pulmonary regurgitation, and were compared to Sham animals (n=6). Longitudinal hemodynamic assessments, including pressure-volume analysis and cardiac magnetic resonance imaging, were performed. VAC was defined as the ratio of end-systolic elastance to effective arterial elastance. Over the follow-up period of 4 months, VAC was preserved in the rTAP group. Effective arterial elastance was significantly lower in rTAP animals (P=0.001), while end-systolic elastance remained unchanged. Lower end-diastolic pulmonary artery pressures and increased early systolic ejection were observed in rTAP, correlating with higher VAC. Ventriculo-arterial coupling remains preserved in chronic pulmonary regurgitation due to decreased afterload, making it unsuitable as an early marker for right ventricular dysfunction. Low afterload, a consequence of diastolic emptying of the pulmonary artery into the right ventricle, may pseudo-normalize systolic function. Alternative markers e.g. focusing on diastolic function and atrio-ventricular interactions should be investigated.