Density of aortopulmonary collaterals predicts in-hospital outcome in tetralogy of Fallot with pulmonary stenosis.

OBJECTIVES: The aim of this study was to characterize the anatomy of aortopulmonary collateral (APC) arteries in tetralogy of Fallot and pulmonary stenosis and to determine whether APC density identified on preoperative multidetector cardiac computed tomography predicts in-hospital outcome. METHODS: The retrospective single-centre study includes consecutive 135 (2015-2019) patients who underwent one-stage repair. Preoperative multidetector cardiac computed tomography, echocardiography and clinical outcomes were reviewed. The cut-off value of indexed total distal APC cross-sectional area (APC-CSA) was identified by receiver operating characteristic curve. Logistic regression was used for predictors analysis. RESULTS: The median age and body weight were 19.7 (10.1-89.7) months and 10 (8.3-18) kg. A total of 337 APCs were detected with only one demonstrating severe stenosis. There was a strong and significant correlation between mean APC diameter per patient and age (r = 0.70, P < 0.001). APCs were imaged but mainly received no interventions. In-hospital mortality was similar between patients with high (indexed APC-CSA ≥3.0 mm2/m2) and low (<3.0 mm2/m2) APC density (P = 0.642). Significantly greater patients with high indexed APC-CSA experienced the in-hospital composite outcome of death, arrest, renal/hepatic injury, lactic acidosis or extracorporeal membrane oxygenation (P = 0.007). High APC density was associated with greater dosing (P = 0.008) and longer (P = 0.01) use of inotropic support, prolonged pleural drainage (P = 0.013), longer ventilation (P = 0.042), intensive care unit (P = 0.014) and hospital (P = 0.027) duration. No reintervention and death occurred in the follow-up with the median duration of 24.4 (11-36.6) months. Multivariable analysis showed the Nakata index (P = 0.05) and high APC density (P = 0.02) independently predicted the composite outcome. CONCLUSIONS: In tetralogy of Fallot and pulmonary stenosis, APCs are likely to be dilated bronchial arteries. Preoperative multidetector cardiac computed tomography-derived APC density was as important as Nakata index in predicting the occurrence of in-hospital composite outcome. The APC-CSA of 3.0 mm2/m2 maybe considered as a threshold for risk stratification.