Pulmonary Arteriovenous Malformations: A Rare Cause of Ischemic Stroke

Abstract

A 24-year-old woman was admitted for seizures. Magnetic resonance imaging revealed a subacute infarct of the right frontal operculum. Transthoracic echocardiogram showed evidence of patent foramen ovale (PFO). Further study with transesophageal echocardiogram showed no PFO, but signs of a pulmonary arteriovenous malformation (PAVM) that was confirmed on ensuing chest CT angiogram. May-Thurner syndrome (MTS) was suspected and confirmed by magnetic resonance venography showing 70% narrowing of the left common iliac vein. The PAVM was successfully coiled and the patient was discharged without deficits. Noncontrast CT at one-month follow up showed no residual PAVM sac. Literature shows there is a median two-year delay from cerebral event to diagnosis of PAVM. Over 80% of PAVMs are related to hereditary hemorrhagic telangiectasia (HHT) and are generally seen in multiples, but may also been seen as an idiopathic and/or isolated defect. The risk of neurological complications rises with a patient's age and the quantity of PAVMs. Initial workup should include screening with transthoracic contrast echocardiography followed by CT angiography for definitive diagnosis. Embolotherapy is considered gold standard as it reduces the risk of paradoxical emboli and other complications.

Keywords: ischemic stroke; may-thurner syndrome; pulmonary ateriovenous malformation.

Figure 1. MR imaging.

(A) Axial diffusion weighted imaging (DWI) MRI showing a subacute right frontal opercular infarct. (B) Axial pelvis magnetic resonance venography (MRV) showing compression of the left common iliac vein by the overlying right common iliac artery and the posterior vertebral body consistent with May-Thurner syndrome.

Figure 2. Coil embolization.

(A) Digital subtraction angiogram (DSA) confirming a 1.6 cm x 1.3 cm x 1.5 cm pulmonary arteriovenous malformation (PAVM) located in the right lower lobe (black arrow) with a 4 mm feeding artery (white arrow) and a 7 mm dilated draining vein (orange arrow). (B) DSA highlighting complete occlusion of the PAVM with coil embolization of the feeding vessel (black arrow).