Insight Into the Multifactorial Nature of Platypnea-Orthodeoxia Syndrome: Not Just a Solo

Background: Platypnea-orthodeoxia syndrome (POS) is a rare condition with complex pathophysiology resulting from an anatomical site of shunting, mostly a patent foramen ovale (PFO), and factors promoting a right-to-left (R-L) shunt. Case Summary: A 54-year-old man was referred to our center for unexplained respiratory failure, exacerbated by sitting. A suspicion of POS was raised, and transesophageal echocardiography demonstrated a wide stretched PFO with R-L shunting, related to the presence of an aortic root aneurysm and right hemidiaphragm elevation, both compressing the right atrium, as well as a prominent eustachian valve. The patient underwent valve-sparing aortic root replacement and concomitant PFO closure, with resolution of symptoms. Take-Home Messages: Multiple factors promoting R-L shunt have been associated with POS. The treatment of choice is represented by the correction of the anatomical shunt. Multidisciplinary team discussion is paramount for the diagnosis and management of this complex condition.