Case Report
Copyright ©2013 Baishideng Publishing Group Co., Limited. All rights reserved.
World J Clin Cases. Jun 16, 2013; 1(3): 108-110
Published online Jun 16, 2013. doi: 10.12998/wjcc.v1.i3.108
Paradoxical embolus straddling patent foramen ovale demonstrated by computed tomographic pulmonary angiography
Laura Cormack, John T Murchison
Laura Cormack, John T Murchison, Department of Radiology, Edinburgh Royal Infirmary, Edinburgh EH16 4SA, United Kingdom
Author contributions: Both authors contributed to the conception and design of report, drafting the article and final approval of the version to be published.
Correspondence to: John T Murchison, MBChB, BSc, DMRD, FRCP, FRCR, Consultant Radiologist, Department of Radiology, Edinburgh Royal Infirmary, Little France Crescent, Edinburgh EH16 4SA, United Kingdom.
Telephone: +44-131-2423775 Fax: +44-131-2423776
Received: January 22, 2013
Revised: April 24, 2013
Accepted: May 9, 2013
Published online: June 16, 2013
Processing time: 142 Days and 23.5 Hours

An elderly gentleman presented to the emergency department with a recent history of dyspnoea, collapse and transient neurological symptoms. He was noted to be hypoxic with a significantly elevated D Dimer. A computer tomography pulmonary angiogram demonstrated a large embolus with a further filling defects within the left and the right atria, abutting the inter-atrial septum. Suspicion of a paradoxical pulmonary embolus was raised and the patient subsequently underwent echocardiography which confirmed a patent foramen ovale (PFO). He was commenced on warfarin therapy. In patients with elevated right heart pressure, a PFO can be unmasked and give rise to cerebral emboli. Clinical suspicion should be raised in patients with pulmonary emboli or deep venous thrombosis if there is a concomitant history of focal neurological symptoms.

Keywords: Pulmonary embolus, Paradoxical embolus, Computer tomography pulmonary angiogram, Patent foramen ovale, Stroke

Core tip: Patent foramen ovale (PFO) are common but usually closed and asymptomatic due to the greater pressure in the left heart. They however pose a particular risk for patients with large pulmonary emboli (PE) where they can open providing a right to left shunt when the right heart pressure rises due to pulmonary arterial obstruction by PE. In these circumstances thrombus can transit the PFO paradoxically embolising systemically. We report a case of a patient with a large PE who had a cerebral embolus where thombus is imaged straddling the PFO at computer tomography pulmonary angiography.