Left Atrial Appendage Volume Increased in More Than Half of Patients with Cryptogenic Stroke

Abstract

BackgroundIschemic strokes without a well-defined etiology are labeled as cryptogenic, and account for 30–40% of strokes in stroke registries. The left atrial appendage (LAA) is the most typical origin for intracardiac thrombus formation when associated with atrial fibrillation. Here, we examined whether increased LAA volume detected with cardiac computed tomography (cCT) constitutes a risk factor in cryptogenic stroke patients.MethodsThis study included 82 stroke/TIA patients (57 males; mean age, 58 years) with a diagnosis of cryptogenic stroke after extensive radiological and cardiological investigations. Cases were classified using the TOAST criteria modified by European Association of Echocardiography recommendations for defining cardiac sources of embolism. Forty age- and gender-matched control subjects without cardiovascular diseases were selected for pair-wise comparisons (21 males; mean age, 54 years). LAA volume adjusted for body surface area was measured three dimensionally by tracing the LAA borders on electrocardiogram-gated CT slices.ResultsIn control subjects, mean LAA volume was 3.4±1.1 mL/m2. Mean+2SD, which was considered the upper limit for normal LAA volume was 5.6 mL/m2. In paired Student t-test between the patient group and matched controls, LAA volume was 67% larger in cryptogenic stroke/TIA patients (5.7±2.0 mL/m2 vs. 3.4±1.1 mL/m2; P<0.001). Forty-five (55%) patients with cryptogenic stroke/TIA had enlarged LAA.ConclusionLAA is significantly enlarged in more than half of patients with cryptogenic stroke/TIA. LAA thrombosis may contribute to the pathogenesis of stroke in patients considered to have cryptogenic stroke after conventional evaluation.

Soluble Urokinase-type Plasminogen Activator Receptor Predicts All-cause 5-Year Mortality in Ischemic Stroke and TIA

“…This 5-year follow-up study is part of the EmbodeteCT study (17)(18)(19). Between March 2005 and November 2009, patients admitted to our university hospital because of acute stroke/TIA with suspected cardioembolic etiology but without known atrial fibrillation (AF) were evaluated as study candidates.…”

“…In an extension to the routine imaging protocol, a combined examination of the heart, aorta, and cervicocranial arteries with computed tomography together with transthoracic and transesophageal echocardiography were performed to define the etiology of stroke (18). For volume measurements of infarcted cerebral tissue, 4.5-5 mm transversal slices were reconstructed in brain computed tomography in the subacute phase (>2 days).…”

Determinants of Left Atrial Appendage Volume in Stroke Patients without Chronic Atrial Fibrillation

“…The risk of stroke has been suggested to double for every 10 mm increment in LA diameter in males [34]. Further investigations have confirmed the correlation between stroke/TIA risk and BSA adjusted LA volume enlargement [5].…”

“…In a recent study, over half of all cryptogenic stroke/TIA patients had an enlarged LAA, indicating that cardioembolism may play a role in the mechanism of stroke in these patients [5]. Chronic AF and PAF are generally considered causative factors for secondary LAA enlargement [7].…”

“…Volumes of the LAA are presented with adjustment for BSA, which was calculated using Mosteller’s formula [11]. In our previous study intra-class correlations (ICC) for the LAA volume measurements resulted in almost perfect reproducibility between different observers (ICC = 0.96) and the same observer (ICC = 0.95) [5].…”