Abstract 12718: Prediction of Left Atrial Appendage Blood Flow Velocity by Brain-type Natriuretic Peptide and CHA2DS2-VASc Score in Patients With Atrial Fibrillation

Introduction:Left atrial appendage blood flow velocity (LAAV) is an estimate of contractile function of left atrial appendage (LAA), and reduced LAAV is associated with higher risk of thrombosis and stroke in patients with atrial fibrillation (AF).Hypothesis:LAAV could be estimated by clinical parameters such as brain-type natriuretic peptide (BNP) or CHA2DS2-VASc score in patients with AF.Methods:Study patients were consisted of consecutive 215 patients (Age; 66?11 years, male gender; 71.2%) with AF who underwent transesophageal echocardiography (TEE) and whose BNP was measured within 2 days before TEE study. We calculated CHA2DS2-VASc score based on medical record. Exclusion criteria were end-stage renal failure, mitral stenosis, history of LAA closure, and open heart surgery within 2 weeks. We investigated the correlation between LAAV and BNP or CHA2DS2-VASc score. We constructed ROC curve for detection of LAAV?20cm/s, which is an independent predictor for thrombus formation and embolism in SPAF-III trial.Results:Average of LAAV in the study patients was 45.2?19.9 cm/s, and LAAV?20cm/s was observed in 17 patients (7.9%). CHA2DS2-VASc score was 2.2?1.6, and BNP value was 126.7?165.8 pg/ml. There was a significant correlation between BNP and LAAV (R=0.43, p<0.0001). CHA2DS2-VASc score also had a significant correlation with LAAV (R=0.27, P<0.0001). ROC curve analysis demonstrated that BNP could detect LAAV?20cm/s with 77.3% of sensitivity and 76.5% of specificity using 170.6 pg/ml as a cutoff value, and that CHA2DS2-VASc could detect it with 63.6% of sensitivity and 82.4% of specificity using 3 as a cutoff value. There was no significant difference in C-statics between two ROC curves (0.818 vs. 0.779, p=0.64). A significant correlation was also observed between BNP and LAAV (R=0.23, p=0.01) in 123 patients who showed regular sinus rhythm at the time of TEE study, but no significant correlation between CHA2DS2-VASc score and LAAV in them.Conclusions:BNP and CHA2DS2-VASc score were correlated with LAAV in patients with AF, and they could detect patients with low LAAV with good accuracy. BNP also showed correlation with LAAV at the time of sinus rhythm. BNP as well as CHA2DS2-VASc score could be useful for the risk stratification of patients with AF.