Abstract Body (Do not enter title and authors here): We describe a 42-year-old female with a past medical history significant for antiphospholipid syndrome (APS) who presented as a transfer to our facility for evaluation of stroke-like symptoms. She experienced acute onset dysarthria, left-sided weakness and a fixed rightward gaze preference. She was not a candidate for tenecteplase due to outpatient direct oral anticoagulant therapy. Computed tomography (CT) imaging of the head confirmed an acute infarct to the middle cerebral artery territory. She was taken for an emergent mechanical thrombectomy which she tolerated well. Repeat CT imaging ruled out hemorrhagic conversion. Transthoracic echocardiography revealed a 1.3 cm x 1.2 cm spherical mobile mass on the mitral valve, associated with a moderate to severe mitral regurgitation that was confirmed by transesophageal echocardiogram. The patient's respiratory status unfortunately declined and was consequently intubated. Blood cultures were negative and there was no history of intravenous drug use. The vegetation was considered marantic, representing nonbacterial thrombotic endocarditis (NBTE) secondary to APS and medication nonadherence. Cardiothoracic surgery offered surgical valve replacement after clinical recovery on an outpatient basis. She was subsequently extubated, transitioned to warfarin as recommended by hematology, weaned off supplemental oxygen, and discharged to inpatient rehab.

Antiphospholipid syndrome is an autoimmune condition characterized by recurrent thrombosis and pregnancy morbidity, accompanied by the presence of antiphospholipid antibodies. A known complication of APS is NBTE and embolization of these vegetations contributes to the risk of thromboembolic events, such as stroke as seen in our patient. We discuss a multidisciplinary approach is imperative to ischemic stroke workup, particularly in the context of APS with developing catastrophic antiphospholipid syndrome. We also point out evidence suggesting direct oral anticoagulants are less effective than warfarin for thrombus prevention, however contemporary studies are limited.