The impact of age on right ventricular morphology and function late after repair of Tetralogy of Fallot: a cardiac magnetic resonance study

Abstract

Background: Cardiac magnetic resonance (CMR) is the gold standard to evaluate right ventricular (RV) hemodynamics after repair of tetralogy of Fallot (TOF). CMR markers such as severe RV dilation and biventricular dysfunction are independent predictors of death, sustained VT and heart failure. However, the relationship between patient's age at surgical correction and RV function is not fully understood. A better understanding of determinants of outcome after repair of TOF could improve prediction of adverse events and clinical management. Methods: All patients who underwent hemodynamic evaluation by CMR late after repair of TOF in two pediatric cardiology centers, between 2011 and 2012, were included in the study. Previous surgical repair included either transannular infundibular RVoutflow tract reconstruction. Surgical data (including era and details of repair) and CMR parameters (RV volumes and function, pulmonary and tricuspid regurgitation, pulmonary branches stenosis) were collected. Results: The study enrolled 165 patients (65% males) aged 18±6.4 (range 5-38) years who had undergone repair at the age of 1.4±1.7 (range 0.2-12 years) years. RV end-diastolic volume indexed (RVEDVi) was correlated both with PRF (p=0.001, r=0.526) and RVOT obstruction and/or bilateral stenosis of pulmonary arteries (p=0.01). On the other hand RVEDVi was not correlated with patient's age or time interval from surgical repair. RV ejection fraction (RVEF) decreased in relation to RV dilatation (p=0.01; r=-0.462), as expected. There was a significant relationship between RVEF and left ventricular ejection fraction (p<0.001). Older age at repair significantly affected RVEF (p=0.04; r=-0.235), which conversely did not show any relationship with patient age or time interval from surgical repair. Conclusion: Patient's age and time interval from surgical repair might not have a fundamental role in RV dilation, which is mostly related to PRF. In contrast RV dysfunction is significantly related to an older age at surgical repair, independently of ventricular dilation. Larger longitudinal follow-up studies are needed in order to extend our observations and define the exact role of each element in predicting the adverse outcome of patients with repaired TOF.