Collateral or fistula? Coronary artery as the primary source of pulmonary blood flow in a patient with pulmonary atresia and ventricular septal defect

In patients with pulmonary atresia and ventricular septal defect (PA/VSD), a coronary artery being the primary source of pulmonary blood flow is a rare entity. We describe two cases of PA/VSD with coronary-to-pulmonary artery fistula with emphasis on the role of Computed Tomographic Angiography (CTA) in depicting all the sources of pulmonary blood supply, to predict surgical management and need for unifocalization of Major Aortopulmonary Collateral Arteries (MAPCA's).