Major Aortopulmonary Collateral Arteries (MAPCA’s)

When Pulmonary Atresia occurs, there is no way for blood to travel from the heart to the lungs.  Instead Beckham’s heart created these MAPCA’s or collaterals to deliver blood to the lungs for oxygenation.  If you think about it, it’s actually quite miraculous that his body formed these pathways for his blood to get to the lungs.  These MAPCA’s are extremely complicated and rare as far as congenital heart defects go.  Instead of coming form the pulmonary trunk, they arise from the aorta and other systemic arteries.  MAPCA’s can vary in number, location and stenosis or narrowing.  The surgery required to bring all of these collaterals together is called Unifocalization.