Surgically palliated double-inlet left ventricle with transposition of the great arteries mistaken for aortic aneurysm with dissection

We report a 23-year-old male with history of double-inlet single ventricle with transposition of the great arteries who is s/p pulmonary artery banding, a Damus–Kaye–Stanzel anastomosis, and Fontan procedure during infancy and childhood who now presents with chest pain. A chest CTA at an outside hospital was thought concerning for the presence of a thoracic aortic aneurysm with dissection, prompting immediate transfer to our institution. However, repeat chest CTA at our institution revealed the predicted anastomoses based on his surgical procedures, which was misinterpreted as aortic aneurysm and dissection. An understanding of the physiology of his surgically repaired congenital heart disease is critical in interpreting his subsequent chest CTA and arriving at the appropriate clinical conclusion.