Clinical presentation of persistent 5th aortic arch: 3 new cases.

We report 3 cases of a persistent 5th aortic arch. This anomaly is usually associated with other intracardiac defects. Although all 3 patients were found to have similar vascular structures that were best explained by the persistence of the 5th aortic arch into postnatal life, the clinical presentations were quite different. One patient presented with coarctation of the aorta, the 2nd patient with cyanosis, and the 3rd patient with pulmonary overcirculation. The 2nd case is unique in that the 5th aortic arch was found to be sensitive to prostaglandin E1. Understanding the embryologic derivation and differing presentations of a persistent 5th aortic arch aids in diagnosis and management of these patients.