Risk of left atrial appendage thrombus in patients scheduled for ablation for atrial fibrillation: beyond the CHA2DS2VASc score

INTRODUCTION Atrial fibrillation (AF) increases the risk of thromboembolic events by promoting clot
formation in the left atrial appendage (LAA). Transesophageal echocardiography (TEE) is routinely used to
exclude the presence of an LAA thrombus before AF ablation. So far, it has not been established what is
the optimal combination of noninvasive parameters for thromboembolic risk stratification in this setting
and whether patients at very low risk require TEE.
OBJECTIVES The aim of the study was to assess predisposing factors for an LAA thrombus in patients
scheduled for AF ablation and to identify those patients in whom preprocedural TEE is not necessary.
PATIENTS AND METHODS In consecutive 151 patients (107 men; mean age, 57 ±10 years) the type of
AF and renal function were assessed in addition to the CHA2DS2VASc score to improve thromboembolic
risk stratification.
RESULTS An LAA thrombus or dense echo contrast with a strong suspicion of a probable thrombus was
detected in 15 patients (10%). Diabetes, age of 65 years or older, persistent AF, and estimated glomerular
filtration rate (eGFR) of less than 60 ml/min/1.73 m2 were predictors of the LAA thrombus. A multivariate
logistic regression analysis showed that only persistent AF and an eGFR of less than 60 ml/min/1.73 m2
were independent predictors of the LAA thrombus. The receiver operating characteristic curves showed
that the greatest area under the curve (0.845) was achieved for the CHA2DS2VASc-AFR (CHA2DS2VASc
plus the type of AF and renal function); the difference was not significant. A CHA2DS2VASc-AFR score
of 2 or greater or a CHA2DS2VASc score of 1 or greater identified patients with the LAA thrombus with
a sensitivity of 100% (and specificity of 54% and 36%, respectively).
CONCLUSIONS In patients scheduled for AF ablation, an LAA thrombus or dense echo contrast is a
relatively common finding despite routine anticoagulant treatment. The addition of AF type and renal
function to the CHA2DS2VASc score slightly improves thromboembolic risk stratification and may help
identify patients who do not need preprocedural TEE.