When the Aorta Forms a Vascular Ring Around the Trachea and Oesophagus Introduction Double Aortic Arch — DAA — is a congenital abnormality of the aortic arch in which the ascending aorta divides into right and left arches that pass around the trachea and oesophagus before rejoining to form the descending aorta. Unlike ASD, VSD … Continue reading Double Aortic Arch