Ischemic Stroke Secondary to Paradoxical Embolism Through a Pulmonary Arteriovenous Malformation: Case Report and Review of the Literature

doi:10.1016/j.jstrokecerebrovasdis.2018.02.015

Journal of Stroke and Cerebrovascular Diseases

Volume 27, Issue 7, July 2018, Pages e125-e127

https://doi.org/10.1016/j.jstrokecerebrovasdis.2018.02.015 Get rights and content

Paradoxical embolism due to isolated pulmonary arteriovenous malformation (AVM) is an uncommon cause of ischemic stroke, with the majority occurring in patients who have not yet been diagnosed with their malformation. We report a 32-year-old man who presented with an abrupt onset of right facial weakness and expressive aphasia. Brain magnetic resonance imaging revealed an acute infarct in the left middle cerebral artery territory and chronic infarcts in the bilateral cerebellar hemispheres. A cardioembolic mechanism was initially considered in the setting of perimyocarditis diagnosed a few months earlier. Transthoracic and transesophageal echocardiograms revealed high volume right to left shunting, but no septal defects. A pulmonary AVM was confirmed with computed tomography angiography and fistualization was successfully treated with embolization. This report highlights a case of undiagnosed pulmonary AVM leading to recurrent paradoxical emboli to the brain. We review the epidemiology, pathophysiology, and management of pulmonary AVMs in relation to stroke risk.

Section snippets

Case Report

A 32-year-old right-handed man was admitted after experiencing sudden onset right facial weakness and language disturbance. He described a 15-minute episode of blurred vision, right-sided facial weakness, slurred speech, and inability to read with intact comprehension of the number system. Past medical history included hypertension, hyperlipidemia, tobacco use, and epilepsy on phenytoin. He was hospitalized 2.5 months prior for perimyocarditis with hypokinesis of the apex noted on cardiac

Discussion

Paradoxical embolization is a recognized cause of ischemic stroke that occurs when thrombotic or bacterial emboli of venous origin occlude arteries of various organs, including the brain, after bypassing the filtering system of the pulmonary capillaries and traveling to the arterial circulation via an abnormal channel.¹ While most paradoxical emboli are likely attributed to patent foramen ovales, PAVMs are another less common source of right-to-left shunting contributing to risk of stroke in

Conclusion

This case highlights the need to consider PAVM in the differential diagnosis for cryptogenic stroke, particularly in young persons with evidence of right to left shunting on cardiac imaging. Embolization is the definitive treatment for clinically significant PAVMs or those with high risk shunting physiology. Current guidelines suggest that patients with treated PAVMs receive follow-up imaging at 3-year intervals.

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Cited by (13)

Noncontrast time-resolved pulmonary magnetic resonance angiography with consecutive beam saturation pulse and variable flip angles using three-dimensional fast spin echo: A preliminary study
2022, Magnetic Resonance Imaging
Citation Excerpt :
Pulmonary arteriovenous malformations (PAVMs) are pulmonary vascular abnormalities that create shunts between the pulmonary arteries and veins [1]. Although most patients with PAVMs are asymptomatic, the direct connection between their vessels can cause various symptoms, such as exertional dyspnea, hypoxemia, ischemic stroke [2], and brain abscesses [3]. Transcatheter embolization of the feeding artery is the primary treatment of choice [4].
To develop and validate a novel noncontrast time-resolved magnetic resonance angiography (NC TR-MRA) using consecutive beam pulses with variable flip angles for visualizing hemodynamics in the pulmonary artery, we performed phantom and volunteer studies and applied the novel NC TR-MRA to a 51-year-old woman with pulmonary arteriovenous malformation (PAVM).The novel NC TR-MRA sequence utilized consecutive multiple-beam saturation pulses with variable flip angles considering venous blood T1 relaxation to alter the visualized blood signal length. The flowing blood signal length is suppressed according to the number of beam saturation pulses. NC TR-MRA in each flow phase was assessed by subtracting the images with and without beam saturation pulses. In the flow phantom study, three flow velocities were used to simulate physiological pulmonary arterial blood flow. Signal profiles along the flow direction were evaluated in each flow phase. In the volunteer study, five healthy volunteers were recruited, and NC TR-MRA was applied to evaluate relationships between the flow-saturated time and signal enhancement rates. Four regions of interest (ROIs) were determined on the proximal and distal portions of the right basal artery. A patient with PAVM was included to validate whether a PAVM lesion could be visualized using NC TR-MRA. The visualized flow signal lengths extended proportionally with the number of beam saturation pulses in the steady-flow phantom at all velocities. In the volunteer study, NC TR-MRA images showed signal enhancement from the proximal to distal portions of the right basal artery with increase in the flow-saturated time. Signal enhancement rates in all ROIs were significantly positively correlated with the flow-saturated time (p < 0.001 in all ROIs). Further, the lesion and its hemodynamics could be explicitly visualized in the patient with PAVM. Hence, NC TR-MRA using beam saturation pulse can visualize the hemodynamics of the pulmonary artery and may be useful for diagnosing and following patients with PAVM.
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DIAGNOSTIC CRITERIA FOR DETERMINING THE TYPE OF THE RIGHT-TO-LEFT SHUNT USING CONTRAST-ENHANCED TRANSCRANIAL DOPPLER ULTRASOUND IN YOUNG PATIENTS WITH ISCHEMIC STROKE/TRANSIENT ISCHEMIC ATTACK
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Case StudiesIschemic Stroke Secondary to Paradoxical Embolism Through a Pulmonary Arteriovenous Malformation: Case Report and Review of the Literature

Section snippets

Case Report

Discussion

Conclusion

Diagn Interv Imaging

Chest

Chest

Mayo Clin Proc

Patent foramen ovale as a risk factor for cryptogenic stroke

Ann Intern Med

Pulmonary arteriovenous malformations. A state of the art review

Am J Respir Crit Care Med

Prevalence of pulmonary arteriovenous malformations as estimated by low-dose thoracic CT screening

Intern Med

Case Studies
Ischemic Stroke Secondary to Paradoxical Embolism Through a Pulmonary Arteriovenous Malformation: Case Report and Review of the Literature