Endotracheal bleeding after arterial switch operation: Think of a bleeding major aortopulmonary collateral artery.

Major aortopulmonary collateral arteries (MAPCAs) in the setting of d-transposition of the great arteries (d-TGA) are a rare and occult finding, as they are often asymptomatic and difficult to detect in preoperative imaging. Consequences of undiagnosed MAPCAs in d-TGA are varied. Rarely, they lead to a catastrophic perioperative bronchial bleeding. Early identification and coiling are crucial. We report the case of a male neonate with d-TGA and ventricular septal defect (VSD) who experienced intrabronchial bleeding by the end of the arterial switch and VSD closure procedure, leading to inability to adequately ventilate and perioperative extracorporeal membrane oxygenation. Early identification and coil embolization were critical in identifying and managing the bleeding collaterals. This case underscores the need for employing emergent cath-angiography to diagnose previously unknown MAPCAs and thus salvaging the child from a dreadful but treatable cause. To our knowledge, this is one of the very few successfully treated cases of arterial switch operation complicated with MAPCA-induced perioperative bronchial bleeding.