Anatomical factors triggering platypnea-orthodeoxia in adults.

Right to left shunting through a patent foramen ovale (PFO) or atrial septal defect (ASD) can cause platypnea-orthodeoxia even in a setting of normal pulmonary artery pressures. However, the late onset of symptoms despite the congenital origin of the anatomical defects is not well understood. We report a case series of patients presenting with dyspnea and orthodeoxia who developed right to left shunting as a result of associated anatomical changes that occur with aging such as tortuosity and elongation of the aorta. We propose that these acquired anatomical changes can favor right to left shunting in the setting of congenital abnormalities, therefore explaining the late onset of symptoms.