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Updated: May 20, 2026

Closure of a Patent Foramen Ovale (PFO): An Intervention Sequence
Published on: December 23, 2022
Platypnea-Orthodeoxia Syndrome in a Patient With Aortic Root Dilation and a Patent Foramen Ovale
A K Prohl1, S Kwiatkowski1, A Samanta1
1Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA.
Background:
Platypnea-orthodeoxia syndrome (POS) is a rare condition characterized by dyspnea and hypoxemia in the upright position that improves when supine.
Case Summary:
A 75-year-old man presented with dyspnea and chronic hypoxemic respiratory failure of unknown etiology. The patient was dyspneic sitting and standing and was free of symptoms when supine. Supine and upright pulse oximetry and bubble study confirmed upright hypoxemia, right-to-left shunting across a patent foramen ovale (PFO), and aortic root dilation. The patient's dyspnea and hypoxemia resolved after device closure of the PFO.
Discussion:
Aortic root dilation is a key anatomical risk factor for right-to-left shunting in POS. Obesity can increase right atrial pressure and is likely synergistic with aortic root dilation. Percutaneous PFO closure is a low-risk curative procedure.
Take-Home Message:
In cases of hypoxemia of uncertain etiology, evaluation for POS with a thorough history and supine and upright pulse oximetry and bubble study can prevent exhaustive diagnostic workups and expedite time to treatment with PFO closure.
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