Etiology of right ventricular restrictive physiology early after repair of tetralogy of Fallot in pediatric patients

BACKGROUND: Right ventricular restrictive physiology (RVRP) is a common finding after repair of Tetralogy of Fallot (TOF). The characteristic feature of RVRP is the presence of a direct end-diastolic flow (EDFF) during atrial contraction in the main pulmonary artery. This end-diastolic forward flow is caused by increased right ventricular end-diastolic pressure due to right ventricular myocardial stiffness and decreased right ventricular compliance. OBJECTIVE: Our main objective is to found out the etiology of RVRP in pediatrics patients who underwent for complete repair of Tetralogy of Fallot (TOF). METHODS: A total of 50 TOF patients have registered for this study in our hospital from January 2017 to September 2018. The patients were divided in two groups, group A with restrictive physiology and group B without restrictive physiology. The patients selected for this study includes TOF patients, TOF patients with atrial septal defect (ASD), and TOF patients with patent ductus arteriosus (PDA). Ventricular hypertrophy and right heart enlargement were evaluated by electrocardiogram and echocardiography. The other parameters we used to compare between these two groups were sex, age, weight, cardio pulmonary bypass (CPB) time, aortic cross clamping time, transannular patch, SP0(2), RV/LV pressure, ventricular hypertrophy, right heart (RH) enlargement, tricuspid annular plane systolic excursion (TAPSE), pulmonary artery systolic pressure (PASP), TAPSE/PASP ratio, pulmonary annular diameter, intubation time, PICU stay and hematocrit (HCT). RESULTS: RVRP was identified in 28 patients (58%). Lower SP0(2) (mean: 84.3 ± 7.9%) with p-value 0.015, transannular patch repair (n = 22, 78.5%) with p-value< 0.001, longer cardiopulmonary bypass (CPB) time (mean: 117.6 ± 23 min) with p-value< 0.001, longer aortic cross clamping time (mean: 91.4 ± 20.26 min) with p-value< 0.001, lower TAPSE, lower PASP,lower TAPSE/PASP ratio and presence of hypertrophy (p-value < 0.001) were identified as etiology for restrictive physiology. It was also found that 77% TOF patients with ASD have a higher risk of RVRP in our study. CONCLUSIONS: In TOF patient’s etiology for right ventricular restrictive physiology are associated with lower SP0(2,) transannular patch repair, longer CPB and longer aortic cross clamping time, hypertrophy, lower TAPSE, lower PASP and lower TAPSE/PASP ratio.