Platypnea and orthodeoxia syndrome as an uncommon clinical indication for a challenging percutaneous patent foramen ovale closure: a case report

BACKGROUND: Platypnea and Orthodeoxia Syndrome (POS) is a rare clinical condition characterized by positional dyspnoea and arterial desaturation. Various mechanisms are related to this syndrome. The simultaneous presence of abnormal anatomical findings [aortic root dilatation, atrial septal aneurysm (ASA), Lipomatous septum, and patent foramen ovale (PFO)] and an occurring ventilation/perfusion mismatch can modify intracardiac haemodynamics leading to POS in elderly patients. CASE SUMMARY: A 70-year-old man was admitted to our emergency department suffering from neurological symptoms. A brain computed tomography scan showed a subdural haematoma and the patient underwent surgical evacuation. Some days later, he experienced an acute pulmonary insufficiency (SpO(2) 63%) due to parenchymal basal pneumonia treated with endotracheal intubation. Two weeks later, despite pneumonia resolution, the patient’s dyspnoea became worse, experiencing deep hypoxia as soon as the patient sat up with a partial resolution on recumbent position. A transoesophageal echocardiogram with bubble-test was performed showing aortic root dilatation and a lipomatous interatrial septum characterized by the presence of tunnel-like PFO with large ASA resulting in a big right to left shunt at rest with no signs of pulmonary hypertension. The patient underwent PFO percutaneous closure intervention and a few days later O(2) therapy was reduced and the patient decannulated. DISCUSSION: This case illustrates how the presence of both intracardiac and extracardiac factors may facilitate the onset of POS in aged patients. Platypnea and Orthodeoxia Syndrome should be considered in patients with unexplained dyspnoea and arterial desaturation related to orthostatism. It has a good prognosis with an improvement of quality of life if the causal factor can be treated.