138 Brain natriuretic peptide predicts left ventricular contractile reserve in asymptomatic degenerative mitral regurgitation

Abstract

Current guidelines recommend mitral surgery in asymptomatic patients with severe degenerative mitral regurgitation (DMR) even when left ventricular (LV) systolic function is preserved. LV longitudinal deformation, quantified with 2D speckle tracking analysis (2DSt), can detect LV contractile reserve (CR). Moreover, plasma brain natriuretic peptide (BNP) may be used for risk stratification in patients with DMR. We sought to assess whether BNP may be used to identify LVCR in asymptomatic DMR. Resting and exercise transthoracic echocardiography was performed in 82 consecutive asymptomatic patients with moderate to severe DMR and with preserved LV systolic function. The presence of LVCR was defined as an exercise-induced changes in global longitudinal strain (GLS) >2%. Simultaneously to resting echocardiography, plasma BNP level was measured. GLS increased during exercise (from 20.9 ± 3.1 to 23.4 ± 3.4%, p < 0.001) and CR was found in 45 patients (56%). Patients with CR were significantly younger (p = 0.025) and had lower LV filling pressure (p = 0.04) than to those without CR. BNP was significantly higher in patients without CR (42.7 ± 2 vs.14.8 ± 2pg/ml, p < 0.0001) and there was a good correlation between BNP and exercise-induced changes in GLS (r = −0.77, p < 0.001). On multivariable analysis, BNP was independently associated with exercise-induced changes in GLS (p < 0.001). ROC curves showed that BNP>26 pg/ml predicted the absence of CR with good accuracy (sensitivity: 92%; specificity: 93%). Moreover, multivariable regression revealed that, after adjustment for age, sex, E/Ea ratio and resting GLS, only BNP was independently associated with CR (OR = 1.4, 95%CI: 1.2–2, p < 0.001). In asymptomatic DMR and normal LV systolic function, CR may be absent in a large proportion of patients (45%). BNP is highly accurate to identify patients with subclinical LV dysfunction and no CR. Consequently, BNP could routinely be used to improve risk stratification.