Detection of Left Atrial Appendage Thrombus by Cardiac Computed Tomography in Patients with Atrial Fibrillation: A Meta-Analysis

OBJECTIVES: Transesophageal echocardiogram (TEE) is considered the gold standard modality in detecting left atrial/LA appendage (LA/LAA) thrombi.  However, this is a semi-invasive procedure with rare but potential life-threatening complications.  Cardiac computed tomography has been proposed as an alternative method.  The purpose of this meta-analysis was to evaluate the diagnostic accuracy of cardiac computed tomography assessing LA/LAA thrombi in comparison with TEE.

METHODS: A systematic review of Medline, Cochrane, and Embase to look for clinical trials assessing detection of LA/LAA thrombi by cardiac computed tomography when compared with TEE in patients with a history of atrial fibrillation before electric cardioversion/pulmonary vein isolation or after cardioembolic cerebrovascular accident was performed using standard approach and bivariate analysis.

RESULTS: Nineteen studies with 2955 patients (men, 71%; mean age, 61±4 years) fulfilled the inclusion criteria.  Most studies (85%, 16 studies) used 64-slide multidetector computed tomography and 15 studies (79%) were electrocardiographic-gated.  The incidence of LA/LAA thrombi was 8.9% (SD, ±7).  The mean sensitivity and specificity were 96% and 92%, whereas the positive predictive value and negative predictive value were 41% and 99%, respectively.  The diagnostic accuracy was 94%.  In a subanalysis of studies in which delayed imaging was performed, the diagnostic accuracy significantly improved to a mean weighted sensitivity and specificity of 100% and 99%, respectively, whereas the positive predictive value and negative predictive value increased to 92% and 100%, respectively.  The accuracy for this technique was 99%.

CONCLUSIONS: Cardiac computed tomography, particularly when delayed imaging is performed, is a reliable alternative to TEE for the detection of LA/LAA thrombi/clot, avoiding the discomfort and risks associated with TEE. 

PMID: 23406625

Posted in Computed Tomography, Echo and tagged , , , , .

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