Tricuspid and pulmonary atresia with coarctation of the aorta: a rare combination possibly explained by persistence of the fifth aortic arch with a systemic-to-pulmonary arterial connection.

A ten-day old baby was found to have tricuspid and pulmonary atresia, and a "ductal-dependent" pulmonary circulation that was prostaglandin-sensitive. An unusual coarctation of the aorta was not recognised until an autopsy was performed, some 11 days after construction of an aortopulmonary shunt. A previously undefined anomaly in this neonate was persistence of the fifth aortic arch with a systemic-to-pulmonary artery connection on the same side as the definitive aorta. The histology of the fifth aortic arch is consistent with the pattern of an arterial duct.