Embolic Stroke with Visualization of “Paradoxical” Thrombus

Case Report 
Embolic Stroke with Visualization of “Paradoxical” Thrombus

Corresponding author Dr. Brigid Dwyer, MD, Boston Medical Center, 72 East Concord Street, C3 Boston, MA 02118, Tel: 617-388-1796; Email: brigid06@alum.mit.edubcd@bu.edu

In cases of embolic stroke, paradoxical thromboembolic events are a frequent consideration and are thought to represent a significant proportion of strokes in patients under 55, especially those at risk for deep venous thrombosis (DVT) [1,2]. Nevertheless, it is extremely difficult to demonstrate clinically the presumed interatrial transport that underlies this particular stroke mechanism.


As a notable exception to this pattern, we submit the case of a 52 year old man diagnosed with invasive squamous cell carcinoma of the tongue and admitted for glossectomy, mandibulotomy, and neck dissection. His post-op course complicated by bilateral DVTs and a pulmonary embolism detected on hospital day eight. He subsequently relayed a complaint of at least several days of abnormal vision to his primary surgical team, with apparent onset approximately one day prior to detection of the DVTs and pulmonary embolism. Therapeutic anticoagulation had begun on hospital day eight.


Exam revealed a dense left homonymous hemianopsia and an MRI of the brain demonstrated a subacute right occipital cortical infarct. While vascular imaging of the head and neck failed to identify a source of this embolic appearing infarct, review of his hospital day eight CT pulmonary angiogram was significant for a saddle embolus extending from the pulmonary artery into the right atrium and visible clot in the left atrium. Transthoracic echocardiogram confirmed presence of a tubular 5 cm x 1 cm mass in the right atrium consistent with right atrial clot crossing the interatrial septum through a patent foramen ovale. Anticoagulation was continued, and he suffered no further strokes or thromboembolic complications during his hospitalization.


This case is unusual in that thrombus crossing the interatrial septum was visualized days prior to detection of a cerebral infarct, in strong support of the proposed mechanism of stroke due to paradoxical embolism. The patient’s post-operative status suggests that the presence of interatrial thrombus was also a fairly recent happening, and possibly in the highest risk period for embolization [3-5].

After embolic stroke with presence of a right to left shunt, thorough workup for sources of venous thrombosis, particularly in those with risk factors, remains crucial to the acute management and long term optimization of such patients.

Keywords: Embolism; Infarction; Stroke in young adults; CT; Ultrasound

Author contributions

Brigid Dwyer, analysis and interpretation of clinical case and imaging, authorship of manuscript. Jose Romero, analysis and interpretation of clinical case and imaging, critical revision of manuscript for intellectual content.


Figure 1. Axial FLAIR MR image demonstrating a subacute right occipital infarct (upper left, red arrow); CT pulmonary angiogram revealing saddle embolus extending from the pulmonary arteries (upper right, red arrow) with thrombus in the right atrium (lower left, red arrow); Transthoracic echocardiogram depicting a tubular, 5×1 cm thrombus traversing a patent foramen ovale (lower right, red arrow).


NIH grants K23AG038444 and 1 R03 AG048180-01A1 were associated with this publication.


Dr. Dwyer reports no disclosures. Dr. Romero reports no disclosures.


1.Overell JR, Bone I, Lees KR. Interatrial septal abnormalities and stroke: a meta-analysis of case control studies. Neurology. 2000, 55(8):1172-1179.

2.Lanz J, Brophy JM, Therren J, Kaouache M, Guo L. Stroke in Adults with Congenital Heart Disease: Incidence, Cumulative Risk, and Predictors. Circulation. 2015, 132(25): 2385-2394.

3.Geerts WH, Pineo GF, Heit JA , Bergqvist D, Lassen MR et al . Prevention of venous thromboembolism: the Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy. Chest. 2004, 126(3 Suppl): 338S-400S.

4.Clive Kearon. Natural History of Venous Thromboembolism. Four Topics in Venous Thromboembolism. Circulation. 2003, 107(23): 1-10.

5.Beckman M, Hooper WC, Critchley S, Ortel T. Venous thromboembolism: a public health concern. Am J Prev Med. 2010, 38(4 Suppl): S495-501.

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