To the Editor:
Paradoxical embolism refers to the clinical phenomenon of a thrombus occurring in the venous vasculature and passing into the systemic circulation.1 Impending paradoxical embolism is even rarer and occurs when the venous embolism is identified on imaging in transit across an intracardiac defect. An increased risk of venous thromboembolism associated with the ChAdOx1 nCoV-19 (Oxford University, Oxford, UK, and AstraZeneca, Cambridge, UK) vaccine has been reported2; however, impending paradoxical embolism after ChAdOx1 nCoV-19 has not previously been identified.
A 60-year-old man was referred with a 4-week history of progressive dyspnea. He was previously active and functionally independent with no relevant medical history. Commencement of the patient's symptoms was preceded by the administration of the ChAdOx1 nCoV-19 vaccine. Initial laboratory investigations were remarkable for elevated D-dimer levels. The respiratory pathogen panel was negative, including 2 severe acute respiratory syndrome coronavirus 2 polymerase chain reaction tests. Computed tomography pulmonary angiography revealed pulmonary thromboembolism at the segmental and subsegmental level bilaterally with the presence of intracardiac thrombus suggestive of impending paradoxical embolus (Fig 1 , A). Echocardiography depicted a serpentine thrombus extending from the right atrium to the left atrium and ventricle through a patent foramen ovale (Fig 1, B; Video 1). Additional investigations failed to identify underlying malignancy or thrombophilia.
Fig 1.
(A) Computed tomography pulmonary angiography demonstrating bilateral pulmonary emboli (arrows). (B) Intraoperative transesophageal echocardiogram demonstrating thrombus within the left atrium (arrow). (C) The retrieved intracardiac thrombus.
Emergency cardiac surgery incorporated thrombus extraction (Fig 1, C), patent foramen ovale closure, and retrograde pulmonary vein flushing. Postoperatively, a retrievable inferior vena cava filter was implanted. Also, oral anticoagulation was started, as further thrombus arising from the inferior vena cava was extracted during surgery. The patient made an uneventful recovery and remained well 12 months after surgery.
Declaration of Competing Interest
None.
Footnotes
Supplementary material associated with this article can be found in the online version at doi:10.1053/j.jvca.2023.05.019.
Appendix. Supplementary materials
Video 1. Intraoperative transesophageal echocardiogram demonstrating thrombus within the left atrium prolapsing through the mitral valve into the left ventricle.
References
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Associated Data
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Supplementary Materials
Video 1. Intraoperative transesophageal echocardiogram demonstrating thrombus within the left atrium prolapsing through the mitral valve into the left ventricle.