Paradoxical embolism following acute pulmonary embolism: diagnosis and outcome

Paradoxical Brain Embolism Caused by Pulmonary Arteriovenous Fistula and Coincident Pulmonary Embolism

The authors encountered a very rare case of paradoxical brain embolism resulting from pulmonary arteriovenous fistula and coincident pulmonary embolism. Enhanced computed tomography was useful for diagnosing this infrequent condition.

Paradoxical brain embolism in an acute stroke

Paradoxical embolism to the cerebral circulation is often difficult to diagnose clinically. We report a case that illustrates the usefulness of transesophageal echocardiography in the detection of paradoxical embolism. An 84-year-old woman presented with bilateral hemispheric strokes. Despite the presence of atrial fibrillation, clinical suspicion of paradoxical embolism led to further investigation. An underlying lower limb deep venous thrombosis was found, lung scintigraphy showed pulmonary embolism, and a right-to-left shunt was detected using contrast-transcranial Doppler ultrasound even without the Valsalva maneuver. Transesophageal echocardiography confirmed a mobile 4-cm serpiginous thrombus wedged into a patent foramen ovale, extending from the right into the left atria. Multiple imaging modalities were used, allowing rapid diagnosis of paradoxical embolism, with an underlying DVT as the mechanism of stroke. Of all the investigations, visualization with TEE proved crucial in confirming the diagnosis.

[Cardiogenic shock due to acute mitral dysfunction after deep venous thrombosis]

Open surgical embolectomy may be life-saving in massive pulmonary embolism. Up to now there are no studies concerning the question whether the foramen ovale should be examined routinely during surgery and whether an open foramen ovale should be closed routinely in the same session. Even case reports regarding this question are missing. We report on a 74-year old female patient who developed pulmonary embolism due to deep venous thrombosis. Six days after successful surgical embolectomy the patient developed cardiogenic shock due to a huge thrombus from the right atrium through the foramen ovale into the left atrium and the left ventricle. Immediate surgical embolectomy of a 40-50 cm huge thrombus was successful. Immediately after surgery upon the cardiac mass the patient showed symptoms of acute right leg ischemia. Thus a second embolectomy was necessary, the surgeon removed a 10 cm thrombus from the right external iliacal artery. There was no evidence of another pulmonary embolism timely related to the paradoxical embolism.

Bilateral renal infarction secondary to paradoxical embolism

Paradoxical embolism is an uncommon but increasingly reported cause of arterial embolic events. Involvement of the kidney is rarely reported. Autopsy studies suggest, however, that embolic renal infarction is underdiagnosed antemortem. We report a case of bilateral, main renal artery occlusion and acute renal failure secondary to paradoxical embolism. Clinical and laboratory data at presentation were not suggestive of renal infarction. Support for the diagnosis of paradoxical embolism, which most commonly occurs across a patent foramen ovale, was made by contrast echocardiography, which provides a sensitive method for detecting right-to-left intracardiac shunts. The often subtle presentation of renal infarction suggests patients with peripheral or central arterial embolic events should be carefully observed for occult renal involvement. Contrast echocardiography should be performed when renal infarction occurs without a clear embolic source to evaluate for paradoxical embolism.