Determinants of the reduction in B-type natriuretic peptide after mitral valve replacement in patients with rheumatic mitral stenosis

Abstract

Background: Plasma B-type natriuretic peptide (BNP) levels are closely related to symptoms in left ventricle (LV) systolic heart failure, although marked regarding heterogeneity levels among subjects are reported.

Aims: To assess the influence of right ventricle on plasma BNP in the patients with different grades of its overload secondary to severe mitral valve stenosis (MVS).

Methods: Plasma BNP was evaluated in MVS patients (n = 27) before valve replacement and during follow-up (FUV) 401 ± 42 days after operation.

Results: Initial examination showed severe MVS (0.9 ± 0.2 cm²), left atrial enlargement (LAI 30 ± 4.5 mm m⁻²), right ventricle diastolic dilatation (RVDI 16 ± 3.6 mm m⁻²), normal LV size/function and elevated BNP levels (166 ± 137 pg ml⁻¹). FUV examination revealed a significant reduction in LAI (27 ± 2.2 mm m⁻²), RVDI (14 ± 1.6 mm m⁻²) and BNP levels (80 ± 35 pg ml⁻¹). The regression analysis of the initial parameters found RVDI to be the strongest predictor (R² = 0.61; P<0.0001) for BNP level, whereas RVDI reduction was the strongest factor for BNP decrease (R² = 0.65; P<0.0001) during FUV.

Conclusions: Right ventricle should be taken into account as a potential important source of plasma BNP owing to the fact that LV size and function are well preserved in MVS patients. RVDI determines BNP plasma levels whereas after MVS removal, the RVDI reduction predicts BNP level decrease.