Association between the N-terminal plasma brain natriuretic peptide levels or elevated left ventricular filling pressure and thromboembolic risk in patients with non-valvular atrial fibrillation

BackgroundWe aimed to investigate the role of brain natriuretic peptide (BNP) levels and left ventricular (LV) filling pressures in thromboembolic risk in patients with non-valvular atrial fibrillation (AF).MethodsAmong 327 patients with non-valvular AF, the ratio of peak early filling velocity to mitral annulus velocity (E/Ea) and N-terminal proBNP (NT-proBNP) was compared according to the presence of left atrial appendage (LAA) dysfunction [presence of spontaneous echo contrast (SEC) ≥ grade 3 and/or reduced LAA emptying flow velocity <20 cm/s].ResultsCompared to patients without LAA dysfunction, patients with LAA dysfunction presented with significantly higher CHADS2 scores (1.24 ± 1.14 vs. 1.68 ± 1.31, p = 0.005), high-sensitivity C-reactive protein (0.36 ± 1.18 mg/dl vs. 0.66 ± 1.32 mg/dl, p = 0.043), and NT-proBNP (765.3 ± 2534.8 pg/ml vs. 2266.9 ± 6117.4 pg/ml, p = 0.002). Furthermore, patients with LAA dysfunction showed significantly higher left atrial volume index (LAVI, 25.1 ± 10.9 vs. 43.1 ± 22.1, p < 0.001) and E/Ea (10.8 ± 7.27 vs. 7.97 ± 2.50 mg/dl, p < 0.001). Plasma log NT-proBNP levels were significantly correlated with the presence of SEC (r = 0.276, p < 0.001), LAA emptying flow velocity (r = −0.492, p < 0.001), LAVI (r = 0.405, p < 0.001), and E/Ea (r = 0.353, p < 0.001). Binary logistic regression analysis showed that high NT-proBNP level >249.7 pg/ml (odds ratio, OR 6.79, 95% confidence interval, CI 3.16–15.55, p < 0.001) and E/Ea >10 (OR 4.41, 95% CI 2.39–8.15, p < 0.001) were independent predictors of LAA dysfunction after adjustment of known thromboembolic risk factors.ConclusionElevated plasma NT-proBNP concentrations and LV filling pressures represented by LAA dysfunction may be reliable surrogate markers for predicting thromboembolic risk in patients with AF.