Aortopulmonary collaterals (APCs) are occluded either preoperatively or at the time of cardiac surgery in patients with pulmonary atresia and ventricular septal defect (PAVSD). If left untreated, APCs are an important cause of deterioration in the early postoperative period. We present here an unusual case with a large residual APC causing refractory low-output state in the early postoperative period. Usual arterial approach failed due to extensive angulation with ostial narrowing. The large residual APC was successfully closed with an Amplatzer duct occluder (ADO) device delivered through the transvenous route.