Congenital unilateral pulmonary atresia with coronary-to-pulmonary collateral artery originating from left circumflex coronary artery.

Major aortopulmonary collateral artery (MAPCA) is a rare vessel anomaly defect arising from the systemic arteries and supplying flow to the pulmonary capillary circulation, which frequently associates with cyanotic heart disease, particularly pulmonary atresia coexisting with ventricular septal defect and tetralogy of Fallot. The branches of MAPCA usually originate from the descending aorta, while a feeding vessel from a coronary artery directed to the pulmonary vasculature is a rare occurrence. Herein, we present the first case of right side pulmonary atresia with a variant of MAPCA originating from the left circumflex coronary artery to the pulmonary capillary circulation in a patient who presented with acute coronary syndrome.