Modern diagnostic methods and approaches to treatment of platypnea–orthodeoxia syndrome in patients with patent foramen ovale

INTRODUCTION: Platypnea is defined as initiation or worsening of dyspnea when a patient moves from a supine to a sitting or standing position. This condition is usually accompanied by orthodeoxia, a rather rapidly (within 2–3 minutes) developing hypoxemia triggered by this change in posture. This review focuses on the pathophysiological mechanisms, diagnostic approaches and methods of surgical treatment of platypnea–orthodeoxia syndrome (POS) in such cardiac pathology as patent foramen ovale (PFO). AIM: To conduct an analysis of the literature reflecting the main modern diagnostic methods and approaches to treatment of POS in patients with PFO. MATERIALS AND METHODS: In writing the review article, a search for literature sources was conducted in the PubMed, Scopus and eLibrary abstract databases for the period up to 2023 inclusive using the following keywords: ‘platypnea–orthodeoxia syndrome’, ‘patent foramen ovale’. RESULTS: POS is a rather rare clinical phenomenon, caused in more than 80% of cases by the existence of the intracardiac shunt, in particular, PFO. In this pathology, deoxygenated blood is discharged into the systemic arterial circulation. The syndrome is usually diagnosed using bubble contrast transthoracic or transesophageal echocardiography. The least traumatic method of PFO closure is percutaneous intervention with the effectiveness reaching 99%. This operation is performed on patients with PFO syndrome to arrest clinical symptoms. CONCLUSION: A number of studies and clinical cases have shown a positive effect of percutaneous closure of PFO in alleviating hypoxia symptoms in patients with POS.