Severe Hypoxemia Due to Elongation and Shunting of Patent Foramen Ovale After Emergent Repair of Thoracic Aortic Dissection

We document the elongation and shunting of a patent foramen ovale (PFO) after thoracic aortic dissection repair in a 63-year-old man. Initially, a presurgical echocardiogram showed insignificant PFO shunting; however, severe hypoxemia and inability to extubate after thoracic aortic dissection repair necessitated further investigation. A repeat transesophageal echocardiogram after cardiothoracic surgery revealed significant PFO elongation with bidirectional shunting. Subsequent urgent transcatheter PFO closure markedly improved oxygenation, allowing for successful weaning from mechanical ventilation. This case highlights the importance of recognizing dynamic PFO changes after thoracic surgery as a reversible cause of postoperative hypoxemia.