Platypnea-Orthodeoxia Syndrome (POS): A Retrospective Study of Percutaneous Closure of the Foramen Ovale in a Single Center.

Platypnea-Orthodeoxia Syndrome (POS) is an uncommon but underdiagnosed condition characterized by dyspnea and oxygen desaturation in the upright position, which resolves in the supine position. The most common cause is a right-to-left intracardiac shunt at the foramen ovale (FO). This study reviews the outcomes of 11 patients who underwent percutaneous FO closure for POS at our center between 2007 and 2023. The cohort consisted of six women and five men, with a median age of 77 years. All patients had cardiovascular risk factors, particularly hypertension. Pre-procedure oxygen saturation was low (median 83%), but all patients showed immediate improvement after FO closure, with a median post-procedure saturation of 97%. The median length of stay before the procedure was 40 days, reflecting the diagnostic delay typical of this syndrome. Postprocedure, the median length of stay was 8 days. No complications were recorded. The study also explores the pathophysiology of POS, identifying potential risk factors such as structural changes in the heart and thoraco-abdominal surgeries that may contribute to the development of this syndrome. These findings confirm that percutaneous FO closure is a safe and effective treatment for POS, offering rapid improvement in oxygen saturation and emphasizing the importance of early diagnosis.