Detection of left atrial appendage thrombus by cardiac computed tomography in patients with atrial fibrillation: a meta-analysis

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. 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. 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%. 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.