Relationship between N-terminal pro-B type natriuretic peptide and extensive echocardiographic parameters in mild to moderate aortic stenosis

Context: The N-terminal pro-B type natriuretic peptide levels (NT pro-BNP) are increased in cases of volume or pressure overload.
Aims: To examine NT pro-BNP levels and enclose whether any relationship is present between the levels of NT pro-BNP and extensive echocardiographic parameters in asymptomatic patients with mild to moderate aortic stenosis (AS).
Settings and Design: A cross-sectional study about the NT pro-BNP levels was conducted in 37 asymptomatic AS patients and compared with 40 controls.
Methods: Patients < 70 years old with mild to moderate AS with a peak transaortic gradient> 20 mm Hg in transthoracic echocardiogram were included in our study. Extensive echocardiographic parameters and NT pro-BNP levels were obtained from these patients and these indices were compared with the control population selected from the patients who had similar clinical characteristics with the AS patients.
Statistical Analysis: NT-proBNP values were found to be distribution free. Spearman correlation coefficient was used for correlation analysis. Mean values were compared by the Kruskal-Wallis test.
Results: The NT pro-BNP levels were increased in patients with AS (median; interquartiles range: 686 [449-855] pg/mL vs. 140 [116-150] pg/mL, P < 0.001). Among patients with AS, when correlation analysis was performed mean transaortic gradient, aortic valve area index, myocardial performance index, E_m /A_m ratio, left-ventricular mass index (LVMI) and E/E_m ratio had correlations (r=0.38, P = 0.026; r=-0.46, P =0.008; r=0.19, P =0,049; r=-0.22, P =0.04, r=0.49, P =0.003 and r=0.53, P < 0.001 respectively) with plasma NT pro-BNP levels. The LVMI (r = 0.49, P = 0.003) and E/E_m ratio (r = 0.53 P < 0.001) have the strongest correlations when compared to other parameters.
Conclusion: Plasma NT pro-BNP levels are increased in even asymptomatic patients with AS and correlated with several echocardiographic parameters related to severity of AS and degree of diastolic dysfunction. As a result, NT pro-BNP levels may be used in the follow-up of asymptomatic patients having mild to moderate AS.