Detection of left atrial thrombus during routine diagnostic work-up prior to pulmonary vein isolation for atrial fibrillation: role of transesophageal echocardiography and multidetector computed tomography.

BACKGROUND: Transesophageal echocardiography (TEE) and multidetector computed tomography (MDCT) are frequently used imaging modalities prior to pulmonary vein isolation (PVI) in order to exclude left atrial (LA) and left atrial appendage (LAA) thrombus and to visualize the anatomy of LA and pulmonary veins. This study aimed to identify predictors of LA/LAA thrombus and to analyze the diagnostic yield of routine pre-procedural TEE and MDCT.

METHODS: 329 patients with drug-refractory atrial fibrillation (AF) (age 62 ± 10 years; 65% males; 247 paroxysmal AF) referred for pulmonary PVI were included. Prior to the procedure, all patients underwent 64-slice MDCT and TEE, which was used as the gold standard. Risk parameters for thrombus formation were determined, including the CHADS(2) and CHA(2)DS(2)-VASc scores.

RESULTS: MDCT identified 10 LA/LAA thrombi (3.0%) (8 false positive, 2 true positive), whereas 7 actual thrombi (2.1%) were detected by TEE (5 false negative by MDCT). Sensitivity and specificity of MDCT was 29% and 98%, respectively, with a negative predictive value of 98% and a positive predictive value of 20%. All patients with thrombus were on effective anticoagulation. In multivariate analysis, diabetes mellitus, CHADS(2) score ≥3, and CHA(2)DS(2)-VASc score ≥4 were significantly associated with LA/LAA thrombus. No thrombus was seen in patients without risk factors.

CONCLUSIONS: In patients presenting for PVI, MDCT does not reliably exclude LA/LAA thrombus. Our study revealed a small but significant prevalence of thrombus despite effective anticoagulation. Diabetes mellitus, CHADS(2) score ≥3, and CHA(2)DS(2)-VASc score ≥4 were independent risk predictors of LA/LAA thrombus.