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Título

Left atrial appendage morphology presenting as a risk factor for stroke in a young patient in the absence of atrial fibrillation: a case report

RESUMO

Case presentation: A 43-year-old woman treated with losartan, aspirin, and simvastatin had a medical history of stroke two years ago without etiological investigation, in addition to using a pacemaker for total atrioventricular block since the age of 20, without atrial fibrillation (AF) documented in previous exams. She arrived at the emergency department with sudden hemiparesis and hypoesthesia on the left side of her body at 10:30pm. On examination, she had a National Institutes of Health Stroke Scale (NIHSS) score of five, a blood pressure of 172/85mmHg and a capillary blood glucose level of 98mg/dL. Cranial computed tomography (CT) performed at 1:00am was normal, and thrombolytic therapy was initiated at 1:30am with full recovery of deficits. On subsequent examination, she had an elevated N-terminal pro B-type natriuretic peptide (NT-proBNP) of 1379.9pg/mL. Carotid and vertebral Doppler findings were unremarkable. Electrocardiography revealed sinus rhythm, and pacemaker telemetry showed no evidence of arrhythmia in the previous four months. Transthoracic echocardiography detected an enlarged left atrial appendage (LAA) and an enlarged left atrium (LA). Transesophageal echocardiography did not reveal any intracavitary thrombi or vegetation. Cardiac CT angiography confirmed the increased LA and LAA, the latter with a non-chicken-wing morphology and without evidence of thrombi inside. The patient was discharged after full anticoagulation at the hospital with prescription of dabigatran, atorvastatin, amlodipine and outpatient follow-up in the neurology and cardiology departments.
Discussion: The LAA originates from the main body of the LA and represents one of the major sources of cardiac thrombus formation. Based on imaging findings, LAA morphology can be classified into simple (chicken-wing morphology – most common and with lower risk of thrombi) and complex (non-chicken-wing). Studies have suggested that complex LAA morphology by itself may lead to stroke, even in the absence of AF, probably because of lower flow velocities compared to simple LAA morphology. In addition, there is evidence that ischemic stroke patients without known AF and with elevated NT-proBNP levels may benefit more from anticoagulants than antiplatelet agents, explaining this patient treatment.
Final comments: We present the case of a patient without documented AF and with two strokes at a young age, of probable cardioembolic etiology due to an LAA of complex morphology.

Palavras Chave

Stroke; cardioembolic; left atrial appendage.