Persistent fifth aortic arch.

FIGURE 1. Aortogram in the frontal view shows a large vessel, the persistent fifth aortic arch (arrow), arising from the distal ascending aorta and joining the pulmonary artery confluence. Persistence of the fifth aortic arch (PFAA) is a rare condition that results in the presence of an abnormal vessel originating from the distal ascending aorta proximal to the innominate artery. The distal connection and underlying cardiac or great vessel anomaly define the varied clinical presentations of this condition.