Major aortopulmonary collateral arteries

Last revised by Andrew Murphy on 11 Mar 2024

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 the 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 a patient does not have MAPCAs 1.

Association
Location

They usually arise from the descending aorta. Less commonly, they may arise from ascending aorta or subclavian arteries.

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