Multi-modal and multi-postural assessment of platypnea-orthodeoxia syndrome triggered by stroke: A case report

Platypnea-orthodeoxia syndrome (POS) is a rare condition where patients suffer from dyspnea and reduced oxygenation while in the sitting position. A 69-year-old man initially experienced dyspnea and hypoxemia in the sitting position after developing hemiplegia and postural instability secondary to a cerebral hemorrhage, but the symptoms improved in the supine position. Transesophageal echocardiography revealed a patent foramen ovale (PFO). In the sitting or semi-Fowler position, increased right-left shunt was observed using Swan-Ganz catheterization and pulmonary perfusion scintigraphy. The PFO closure was performed, which obliterated dyspnea and hypoxemia in the sitting position. In POS associated with PFO, comprehensive pre-operative evaluation using multi-modality tests in different postural settings critically delineates the etiology that guides appropriate treatment strategy.