Correlation between plasma brain natriuretic peptide levels and left atrial appendage flow velocity in patients with non-valvular atrial fibrillation and normal left ventricular systolic function.

Abstract

The left atrial appendage (LAA) flow velocity is an important factor for thrombus formation in patients with non-valvular atrial fibrillation (NV-AF). Recently, the relation of plasma brain natriuretic peptide (BNP) levels and thromboembolism has been reported in patients with NV-AF. The aim of this study was to determine whether the plasma BNP is predictive of lower LAA flow velocity in patients with NV-AF and normal left ventricular (LV) systolic function. A total of 184 patients with NV-AF (132 men; 65±12years, LV ejection fraction; 65±10%) underwent transthoracic echocardiography, transesophageal echocardiography (TEE), and measurement of plasma BNP. The LAA flow velocity was obtained by pulsed Doppler TEE. Multivariate logistic regression analysis demonstrated that plasma BNP levels, left atrial volume index (LAVI), LV mass index (LVMI), and the CHADS2 score were independent predictors of lower LAA flow velocity (<20cm/s). Plasma BNP levels (r=-0.58, p<0.001) were correlated with LAA flow velocity. The area under the curve (AUC) for BNP (AUC 0.803) was larger than that for the CHADS2 score (AUC 0.712), LAVI (AUC 0.664) and LVMI (AUC 0.608) with an optimal BNP cut-off value of 164pg/ml (sensitivity 75.7%, specificity 71.1%). This study showed that a higher plasma BNP was associated with a lower LAA flow velocity in patients with NV-AF and normal LV systolic function. The plasma BNP may complement the role of the CHADS2 score in predicting lower LAA flow velocity.