174 Is Left Ventricular Longitudinal Function a Determinant of Plasma Brain Natriuretic Peptide during Exercise in Patients with Organic Mitral Regurgitation?

IntroductionPlasma brain natriuretic peptide (BNP) may be used for risk stratification in patients with organic mitral regurgitation (OMR). Whether exercise can induce changes in BNP in patients with OMR has never been investigated.Method and resultsResting and exercise transthoracic echocardiography including Doppler, tissue Doppler imaging (TDI) and 2-D speckle-tracking (2DSt) quantification were performed in 56 consecutive patients (61±15 yrs, 54% of male) with moderate to severe OMR. Peak velocity and time-to-peak velocity (TP) were measured using TDI for Ea-, Aa- and Sa-wave. 2DSt was use to evaluate global LV longitudinal strain (GLS). Blood samples were drawn at rest and 5 min after peak exercise to measure plasma BNP level. BNP increases during exercise (from 27±18 to 35±24pg/ml, p<0.001) and peak exercise BNP was correlated to exercise LV ejection fraction (EF) (r=-0.36, p=0.007) and to exercise Sa velocity (r=-0.41, p<0.001), TP-Sa (r=0.32, p=0.02) and TP-Ea (r=0.39, p=0.004). The best correlation with peak BNP was found with peak GLS (r=-0.58, p<0.0001). In addition, there were significant associations between the changes in BNP and the changes in LVEF (r=-0.35, p=0.009), Sa velocity (r=-0.37, p=0.005), TP-Ea (r=0.35, p=0.01), and GLS (r=-0.44, p=0.0001). On multivariate analysis, after adjustment for age, sex and LVEF, only peak GLS and TP-Ea were independently associated with peak BNP (r2=0.34, p