Immediate Reversal of Hypoxemia With PFO Closure in Carcinoid Heart Disease and Platypnea-Orthodeoxia Syndrome

BACKGROUND: Intracardiac shunting via a patent foramen ovale (PFO) is an under-recognized cause of refractory hypoxemia. CASE SUMMARY: A 48-year-old woman with metastatic gastric neuroendocrine tumor involving the tricuspid valve presented with recurrent shortness of breath and severe hypoxemia refractory to supplemental oxygen. Computed tomography angiography ruled out pulmonary embolism. Transthoracic echocardiography with a bubble study demonstrated an interatrial communication suggesting a PFO. Right heart catheterization showed bidirectional shunting. Intracardiac echocardiography confirmed the presence of a large PFO. The patient underwent percutaneous PFO closure with an Amplatzer PFO Occluder, resulting in marked improvement in oxygenation and resolution of respiratory failure. DISCUSSION: This case underscores the importance of considering intracardiac shunts in instances of unexplained refractory hypoxemia and demonstrates the efficacy of percutaneous PFO closure in treating this phenomenon. TAKE-HOME MESSAGES: Consider a PFO in persistent hypoxemia despite a negative pulmonary work-up. Timely percutaneous closure may lead to rapid, sustained improvement.