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Thrombus in transit through a patent foramen ovale: paradoxical embolism
  1. J Raaphorst,
  2. E J Wouda
  1. Department of Neurology, Sint Lucas Andreas Hospital, Jan Tooropstraat 164, 1061 AE Amsterdam, The Netherlands
  1. Correspondence to:
 Dr J Raaphorst
 Department of Neurology, Sint Lucas Andreas Hospital, Jan Tooropstraat 164, 1061 AE Amsterdam, The Netherlands;

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A 54 year old man presented with right sided arm and leg weakness of sudden onset accompanied by progressive shortness of breath, 3 days after discharge following admission to the intensive care unit (ICU) for treatment of his pneumonia. He complained of a painful right calf. On neurological examination he had a right sided hemiparesis and extensor plantar response. Brain computed tomography showed recent left frontal infarction. A ventilation perfusion lung scan was consistent with multiple pulmonary emboli. Subsequently, ultrasound showed right popliteal vein thrombosis. Two dimensional transoesophageal echocardiography revealed a large thrombus, floating in the right atrium, traversing a patent foramen ovale (PFO) into the left atrium (fig 1). Following thoracotomy, the thrombus was extracted and the patent foramen ovale was closed. The patient recovered with no further symptoms.

  Figure 1
Figure 1

 Image of the heart in the oblique plane (50 degrees), at the level of the aortic root. A large thrombus is trapped in a patent foramen ovale and extends into the right and left atrium. T, thrombus; RA, right atrium; LA, left atrium; IAS, interatrial septum; Ao, aorta.

Our patient probably developed deep venous thrombosis (DVT) during his stay in the ICU. Thereafter pulmonary emboli may have caused pulmonary hypertension, thus producing right–left interatrial shunting followed by lodging of a thrombus in the patent foramen ovale. Embolism to the brain occurred either from the venous source through the foramen or from the trapped thrombus in the foramen.

Paradoxical embolism has been postulated as a potential mechanism for stroke in patients with PFO, but documented cases including a “trapped” thrombus and DVT are rare. In stroke patients with PFO, no difference in primary event rates after treatment with either anticoagulants or aspirin, and relatively low detection rates for DVT were found.1,2 Furthermore, an isolated PFO—that is, not in combination with an atrial septal aneurysm, seems not to herald a substantial increased risk of subsequent stroke or death in stroke patients.3,4 Paradoxical embolism thus, only in part explains ischaemic stroke in PFO patients.


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  • Competing interests: none

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