Plasma brain natriuretic peptide concentrations in patients with valvular heart disease

OBJECTIVE Plasma brain natriuretic peptide (BNP) concentrations predict prognosis in patients with valvular heart disease (VHD), but it is unclear whether this directly relates to disease severity. We assessed the relationship between BNP and echocardiographic measures of disease severity in patients with VHD. METHODS Plasma BNP concentrations were measured in patients with normal left ventricular (LV) systolic function and isolated VHD (mitral regurgitation (MR), n=33; aortic regurgitation (AR), n=39; aortic stenosis (AS), n=34; mitral stenosis (MS), n=30), and age-matched and sex-matched controls (n=39) immediately prior to exercise stress echocardiography. RESULTS Compared with controls, patients with VHD had elevated plasma BNP concentrations (MR median 35 (IQR 23-52), AR 34 (22-45), AS 31 (22-60), MS 58 (34-90); controls 24 (16-33) pg/mL; p<0.01 for all). LV end diastolic volume index varied by valve lesion; (MR (mean 77±14), AR (91±28), AS (50±17), MS (43±11), controls (52±13) mL/m(2); p<0.0001). There were no associations between LV volume and BNP. Left atrial (LA) area index varied (MR (18±4 cm(2)/m(2)), AR (12±2), AS (11±3), MS (19±6), controls (11±2); p<0.0001), but correlated with plasma BNP concentrations: MR (r=0.42, p=0.02), MS (r=0.86, p<0.0001), AR (r=0.53, p=0.001), AS (r=0.52, p=0.002). Higher plasma BNP concentrations were associated with increased pulmonary artery pressure and reduced exercise capacity. Despite adverse cardiac remodelling, 81 (60%) patients had a BNP concentration within the normal range. CONCLUSIONS Despite LV remodelling, plasma BNP concentrations are often normal in patients with VHD. Conversely, mild elevations of BNP occur with LA dilatation in the presence of normal LV. Plasma BNP concentrations should be interpreted with caution when assessing patients with VHD.