INTRODUCTION: Platypnea-Orthodeoxia Syndrome (POS) is a rare clinical condition characterized by dyspnea and arterial desaturation exacerbated in an upright position and alleviated in the supine position. The main pathophysiological mechanism involves an intra- or extracardiac right-to-left (R-L) shunt. We report an acute POS presentation secondary to traumatic tricuspid valve rupture.
CLINICAL CASE: A 42-years-old man presented to the ED with new-onset worsening dyspnea. A week prior, he was involved in a car crash with airbag deployment and blunt chest trauma, confining him to bed. In medical history: double surgical aortic valve replacement for endocarditis caused by intravenous drug use. At presentation: BP was 100/65 mmHg, sO2 was 94% on room air. Transthoracic echocardiography revealed a LVEF of 40% with akinesis of the apex and the distal segments. Coronary angiography ruled out LAD artery traumatic injuries. After thorough clinical evaluation, an abnormal drop in sO2 (<80% on room air) was observed in the seated position. A microbubble test demonstrated a massive R-L shunt through the interatrial sept (IAS). Transesophageal echocardiography revealed atrial septal aneurysm, patent foramen ovale (PFO) with R-L shunt, severe tricuspid regurgitation (TR) with the jet directed to the IAS due to a chordae tendineae rupture and posterior leaflet flail. Heart Team discussion: high surgical risk, only the percutaneous closure of the PFO was recommended. The procedure was performed with the deployment of Amplatzer device and resulted free of complications. In the subsequent days, the patient was cautiously mobilized. A 6MWT showed no evidence of desaturation and good effort tolerance. Due to the high surgical risk, a conservative strategy with close clinical and echocardiographic follow-up was adopted regarding the TR. The patient was discharged in clinical compensation and in good general condition. CONCLUSION: This case of POS is categorized among those secondary to intracardiac shunting without an increase in pressures in the right heart. The direction of flows within the right cardiac chambers, determined by the TR jet in this instance, dictates the shunt. This report expands our knowledge of potential POS causes, highlighting the importance of considering rarer etiologies based on the patient 's medical history and presentation. Furthermore, this case emphasizes the necessity for a multidisciplinary approach to assess optimal treatment options.