Paradoxical embolism

Last revised by Hamish Smith on 1 Aug 2018

Citation, DOI, disclosures and article data

Citation:

Smith H, Smith H, Knipe H, Paradoxical embolism. Reference article, Radiopaedia.org (Accessed on 24 Apr 2024) https://doi.org/10.53347/rID-61808

DOI:

https://doi.org/10.53347/rID-61808

Permalink:

https://radiopaedia.org/articles/61808

rID:

61808

Article created:

19 Jul 2018, Henry Smith

Disclosures:

At the time the article was created Henry Smith had no recorded disclosures.

View Henry Smith's current disclosures

Last revised:

1 Aug 2018, Hamish Smith

Disclosures:

At the time the article was last revised Hamish Smith had no recorded disclosures.

View Hamish Smith's current disclosures

Revisions:

3 times, by 3 contributors - see full revision history and disclosures

Systems:

Vascular

Tags:

cases, refs

Paradoxical embolism is a clinical scenario in which an embolism arising in the venous system crosses into the arterial circulation where it causes tissue infarction. The most common clinically important site of embolisation is the cerebral circulation.

The prevalence of paradoxical embolism is likely under reported due to its difficulty to diagnose. It likely makes up a significant portion of cryptogenic strokes, that is strokes that has no identifiable cause. Cryptogenic strokes represent up to 45% of ischaemic strokes. The presence of paradoxical embolism should be considered in these patients.

Clinical presentation

The presentation of a paradoxical embolism depends on the area of resulting infarction. It is usually indistinguishable from other forms of embolisation as the responsible shunts are generally asymptomatic and not diagnosed. Less commonly patient’s may have coexistent hypercoagulable state, deep vein thrombosis or pulmonary embolism.

Pathology

The common underlying pathology in paradoxical embolism in any right-to-left shunt. The emboli itself is usually a venous thromboembolus, however, emboli consisting of fat, air, amniotic fluid and tumour tissue have been reported.

The main routes of paradoxical emboli include:

patent foramen ovale: most common
iatrogenic communication (battle defect, Fontan conduit, Rashkind device)
other congenital anomalies: atrial spetal defect, ventricular septal defect, unroofed coronary sinus
pulmonary arteriovenous malformation
systemic to pulmonary venous shunts
arterioarterial shunts (patent ductus arteriosus) or venovenous communications

Radiographic features

Usually only the resulting arterial occlusion is detected via imaging, which may include:

Radiographic diagnosis of the responsible defect is dependent on the type.

Treatment and prognosis

Treatment can be medical with a combination of anticoagulant and/or antiplatelet therapy. In addition to this percutaneous (e.g. atrial septal occlusion device) or surgical correction of the underling routes of paradoxical embolism can be performed.