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. <Learning objective: Pulmonary perfusion scintigraphy successfully demonstrated the postural change in shunt rate in patent foramen ovale (PFO). Further confirmation by cardiac catherization has strengthened the presumed mechanism (increased shunt and decreased oxygenation with coexisting right atrial pressure elevation) and underlying trigger (maintaining semi-Fowler position). Such multi-modal evaluation convinced us of the validity of invasive closing of PFO for relieving patient's symptoms. Thus, in platypnea-orthodeoxia syndrome associated with PFO, comprehensive pre-operative multi-modal evaluation of the patient in different postural settings is critical in determining the treatment strategy.>.