Abstract 15398: Standing Breathless: A Case of Platypnea-Orthodeoxia Syndrome

Abstract

A 67-year old women with a history of metastatic endometrial cancer, prior pulmonary embolism (PE) (on Xarelto) and mitral valve prolapse presented for 2-3 weeks of exertional dyspnea. Patient presented to oncology clinic with oxygen saturation (SpO2) in the mid-70% on room air requiring supplemental oxygen, and eventually high flow nasal cannula (HFNC). She was transferred to our cardiac intensive care unit for further management of her hypoxia. Physical exam was notable for decreasing SpO2 from supine (99%) to sitting (88%) to standing (79%). In this patient with metastatic cancer, differential diagnosis for hypoxia was broad including pneumonia, metastatic pulmonary disease, doxorubicin-induced cardiomyopathy, and PE. CT chest showed no signs of pulmonary edema, pneumonia, lung metastases, or PE. Transthoracic echocardiogram showed normal left and right ventricular function with moderate aortic regurgitation and mitral regurgitation. However, agitated saline injection showed right to left flow consistent with intraatrial shunt. Transesophageal echocardiogram confirmed large patent foramen ovale (PFO) with atrial septal aneurysm. Given physical examination findings, presence of PFO, and structural abnormalities of intraatrial septum, platypnea-orthodeoxia syndrome (POS) was considered. Right heart catheterization was completed to evaluate shunt physiology and showed unremarkable pressures (RA 1, RV 22/1, PCWP 3, PA 20/3, and LA 2). Venous oxygen saturations did not show any step-up suggesting left to right shunt. Exercise challenge did not result in any significant change in PA or PCWP pressures. Given persistent concern for POS without other clear diagnosis, patient underwent percutaneous closure of PFO with a 30mm Gore Cardioform septal occluder. Patient had resolution of her exertional hypoxia following procedure and was discharged home the next day. The case discusses 1) the importance of history of and physical exam in narrowing diagnosis, 2) utilization of multimodality imaging to evaluate intraatrial shunts, and 3) use of percutaneous methods for PFO closure.