Valvular heart disease: plasma B-type natriuretic peptide levels in patients with pure rheumatic mitral stenosis

OBJECTIVE: Our study is designed to evaluate the plasma BNP levels in patients with pure MS and its possible correlation with clinical and echocardiographic parameters of the disease. METHODS AND RESULTS: The study included 29 patients (27 women, 2 men, mean age 43.4 +/- 11.8 y) with pure mitral valve stenosis in sinus rhythm and 24 age- and gender-matched healthy voluteers (17 women, 7 men, mean age 42 +/- 13 y). Plasma BNP levels were significantly higher in the mitral stenosis group compared to controls (91.1 +/- 69.6 pg/ml vs. 14.4 +/- 9.2 pg/ml, P < 0.0001). In univariate analysis, plasma BNP levels correlated positively with left ventricular end-systolic diameter (r = 0.439, P = 0.041), left atrial diameter (r = 0.772, P < 0.001), peak diastolic transmitral gradient (r = 0.621, P = 0.003), mean diastolic transmitral gradient (r = 0.751, P < 0.001), peak systolic pulmonary artery pressure (r = 0.467, P = 0.044), functional capacity (r = 0.819, P < 0.001) and negatively with left ventricular ejection fraction (r = -0.482, P = 0.020) and planimetric mitral valve area (r = -0.494, P = 0.006). No significant correlation existed between age, end-diastolic diameter and right ventricular diameter (r = 0.185, P = 0.337; r = 0.227, P = 0.309; r = 0.319, P = 0.092; respectively). A receiver operating characteristic (ROC) curve identified a BNP value of 32 pg/ml as the best cut-off for the identification of patients with mitral stenosis with a positive predictive value of 100% and a negative predictive value of 75%. CONCLUSIONS: In this study we found elevated plasma BNP levels in patients with pure MS in sinus rhythm. Plasma BNP levels correlated with disease severity and this can have potential clinical implications, for example in patients undergoing percutaneous balloon mitral valvuloplasty or in patients with poor echocardiographic windows.