Association Between Location of Pulmonary Outflow Obstruction and Right Ventricular Size and Function After Repair of Tetralogy of Fallot, Pulmonary Atresia, and Major Aortopulmonary Collaterals.

Quantification of right ventricular (RV) size and function after tetralogy of Fallot repair is critical for determining timing of reintervention and outcomes. Tetralogy of Fallot patients with pulmonary atresia and major aortopulmonary collateral arteries (TOF/PA/MAPCAs) are a unique group in which the RV is subjected to various loading conditions, allowing for direct comparison. Retrospective evaluation of RV echocardiographic indices in repaired pediatric TOF/PA/MAPCAs patients (2/2002 - 4/2018). Patients were categorized as having conduit stenosis (peak gradient ≥ 2.5 m/s) and/or distal pulmonary artery (PA) stenoses (requiring catheter or surgical intervention and > 1/2 systemic RV pressures). A comparison group (N = 9) included distinct age-matched repaired patients without residual lesions. Indexed right heart dimensions were larger in patients with distal PA stenoses (N = 49) compared to conduit stenosis (N = 26), including RV end-diastolic and end-systolic dimensions (p < 0.01), despite earlier time to reintervention (p < 0.0001). RV fractional area change (FAC) was diminished in patients with distal PA stenoses compared to patients without residual lesions (p = 0.006). Patients with conduit stenosis demonstrated a marked decrement in tricuspid annular plane systolic excursion (TAPSE) z-scores. Repaired TOF/PA/MAPCAs patients with residual distal PA stenoses have larger right heart dimensions compared to patients with conduit stenosis, and decreased RV FAC compared to patients without residual lesions at 1-2 years after repair, suggesting early surveillance and immediate intervention on stenotic PA segments appears warranted to decrease the risk of further deterioration of RV systolic function.