Severe hypoxia caused by ascending aorta elongation due to aortic arch aneurysm

Abstract

Patent foramen ovale, sometimes associated with clinical manifestation, is frequently detected during adulthood. Platypnea-orthodeoxia syndrome, a rare condition characterized by dyspnea and hypoxia aggravated in the upright position, is caused by a right-to-left shunt across a patent foramen ovale. We present a case of a 73-year-old man with severe hypoxia caused by an aortic arch aneurysm that distorted the atrial septal geometry and worsened the right-to-left shunt. Clinicians should consider a right-to-left shunt via a patent foramen ovale when an aortic arch aneurysm causes counterclockwise cardiac rotation. Furthermore, the alveolar-arterial oxygen difference can be used to diagnose platypnea-orthodeoxia syndrome.