Abstract 3565: Serum Levels of pro-B-type Natriuretic Peptide (NT-proBNP) Predict Reduced Left Atrial Function in Patients With Systolic Heart Failure
Purpose Elevated serum B-type natriuretic peptide (BNP) and amminoterminal portion of pro-BNP (NT-proBNP) represent strong diagnostic and prognostic predictors in patients with left ventricular (LV) dysfunction and heart failure (HF). In this setting, high BNP levels have been repeatedly associated with increased left atrial (LA) volume, which is a valuable indicator of pathologic LV filling pressure. However, the correlation between natriuretic peptides and LA function has been less investigated in patients with systolic HF.
Methods The study included 56 patients (86% males; age=66±9 years) with LV ejection fraction (EF) </=45% (mean=33±8%) and NYHA class II–IV receiving standard therapy. Patients underwent transthoracic echocardiography for the evaluation of LA transverse dimensions: maximum LA diameter (LAmax) and minimum LA diameter (LAmin) were measured by M-mode in a short axis view obtained at the level of aortic bulb. LA fractional shortening (FS)(%) was calculated by the formula: [(LAmax − LAmin)/LAmax] X100. On the same day, a blood sample was collected and NT-proBNP levels (pg/mL) were measured by commercially available immunoassay.
Results Mean NT-proBNP levels were 1599±2090 pg/mL. Serum NT-proBNP revealed a significant direct correlation with LAmax (r=0.41, p=0.003) and an inverse correlation with LAFS (r= −0.48, p< 0.0001). At multivariate regression analysis (including demographic variables, cardiovascular risk factors and LV EF), NT-proBNP was the only predictor for LAFS (B= −0.476; p< 0.007). NT-proBNP levels were used to identify patients with reduced LA function as defined by LAFS values below the median (median LAFS=14%). By ROC analysis, NT-proBNP (using a cutoff of 1150 pg/mL) was a highly specific predictor for reduced LA function (area under the curve=0.76; p< 0.001; sensitivity=59%, specificity=99%).
Conclusions In patients with systolic HF, NT-proBNP significantly correlate with LA dysfunction, and predict LA dysfunction with an excellent specificity. In light of the fundamental LA contribution for maintenance of ventricular stroke volume in patients with LV dysfunction, identification of LA dysfunction by NT-proBNP may be of particular clinical relevance for therapeutic interventions and monitoring.