Myocardial stiffness is an important determinant of the plasma brain natriuretic peptide concentration in patients with both diastolic and systolic heart failure

Abstract

Plasma brain natriuretic peptide (BNP) concentration increases in proportion to heart failure (HF) severity. Although plasma BNP decreases to a certain level by optimal treatment, there is significant heterogeneity in the baseline value among individuals. The underlying mechanism of the steady-state plasma BNP levels remains still controversial. We investigated the hypothesis that myocardial stiffness (K(m)) is a major determinant of the plasma BNP level. In 19 patients with diastolic HF [DHF; left ventricular ejection fraction (LVEF) > or =4 5%], 18 with systolic HF (SHF; LVEF < 45%), and 12 controls, left ventricular (LV) performance variables and the results of the stress-strain analyses were obtained by the combined simultaneous measurement of echocardiographic and haemodynamic data, and compared with the plasma BNP level. In DHF, a significant correlation was observed between plasma BNP and fractional shortening (P = 0.010), pulmonary capillary wedge pressure (P = 0.030), end-diastolic pressure (P = 0.006), time constant of the LV isovolumic-pressure decline (P = 0.049), end-diastolic stress (P = 0.012), and K(m) (P = 0.004), respectively. In SHF, a significant correlation was observed between plasma BNP and end-diastolic stress (P = 0.036), chamber stiffness (P = 0.048), and K(m) (P = 0.003), respectively. In stable conditions, K(m) may be the most important determinant of the plasma BNP production in patients with both DHF and SHF.