Author + information
- Received October 21, 2018
- Accepted October 23, 2018
- Published online December 26, 2018.
- Ashish H. Shah, MD, MD-Research∗ (, )
- Amir Ravandi, MD, PhD and
- Malek Kass, MD
- ↵∗Address for correspondence:
Dr. Ashish H. Shah, St. Boniface Hospital, Y3006, 409 Tache Avenue, Winnipeg, Manitoba R2H 2A6, Canada.
A 65-year-old woman was admitted to the hospital with a transient ischemic attack. Her medical history included a diagnosis of carcinoid syndrome that was treated with chemotherapy. The patient reported progressive dyspnea with minimal activity for the past 2 weeks. Physical examination demonstrated her to be significantly hypoxic, with oxygen saturation in the 70s that partially improved on high-flow oxygen. Transthoracic echocardiography demonstrated the presence of severe tricuspid regurgitation and a patent foramen ovale (PFO) with right-to-left shunt. Cardiac catheterization demonstrated that the mean left atrial pressure (11 mm Hg) was higher than the mean right atrial pressure (9 mm Hg), and there was no evidence of pulmonary hypertension. Oxygen saturation in each pulmonary vein ranged between 97% and 99%, whereas there was a significant step-down in the left atrium (65%). Angiography in the superior vena cava demonstrated blood flow toward the tricuspid valve into the right ventricle (Online Video 1), whereas the flow from the inferior vena cava (IVC) was streaming toward the interatrial septum and to the left atrium through the PFO (Figures 1A to 1C, Online Video 2). The patient underwent successful transcatheter closure of the PFO using a Gore 25-mm PFO occluder, and saturation normalized within minutes of device deployment. She has remained asymptomatic since discharge.
Platypnea-orthodeoxia syndrome is an uncommonly observed condition, characterized by right-to-left shunting, in the absence of elevated right-sided pressure, mainly through a PFO, resulting in systemic hypoxia. In normal subjects, 4-dimensional flow magnetic resonance imaging has demonstrated a clockwise pattern in the right atrium, when viewed from the right side of the patient, whereas previously published work from others and us has reported counterclockwise vortex formation in the right atrium responsible for right-to-left shunting. Such alteration is described to be due to a change in the relationship among the right atrium, superior vena cava, and IVC (1,2). Streaming of IVC flow toward the interatrial septum reminds us of in utero oxygenated IVC blood streaming through a PFO into the left atrium for systemic perfusion, mainly of the brain. Such a flow pattern is also responsible for increased likelihood of identifying a PFO, when contrast injection is performed from the IVC instead of upper limbs that drain through the superior vena cava.
The authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- Received October 21, 2018.
- Accepted October 23, 2018.
- 2019 American College of Cardiology Foundation
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