Major aortopulmonary collateral arteries
Major aortopulmonary collateral arteries (MAPCAs) are persistent tortuous fetal arteries that arise from the descending aorta and supply blood to pulmonary arteries in the lungs usually at the posterior aspect of hilum.
Pathology
Embryologically, the intersegmental arteries regress with the normal development of pulmonary arteries.
They may persist to supply the pulmonary arteries when there is no flow or very little flow into the pulmonary arteries from the right ventricle. If there is an alternate supply to the pulmonary arteries (e.g. patent ductus arteriosus), then the fetal arteries regress and such patient does not have MAPCAs .
Association
- pulmonary atresia with ventricular septal defect
- tetralogy of Fallot with severe pulmonary stenosis
Location
They usually arise from the descending aorta. Less commonly, they may arise from ascending aorta or subclavian arteries.
