Amount of left ventricular hypertrophy determines the plasma N‐terminal pro‐brain natriuretic peptide level in patients with hypertrophic cardiomyopathy and normal left ventricular ejection fraction

摘要

Background: N‐terminal pro‐brain natriuretic peptide (NT‐proBNP) is increased in patients with hypertrophic cardiomyopathy (HCM); however, the determinants of NT‐proBNP level have not been clarified in HCM. Hypothesis: This study was performed to determine the relationship between NT‐proBNP levels and various echocardiographic variables of patients with HCM and normal left ventricular ejection fraction (LVEF). Methods: We assessed plasma NT‐proBNP levels and echocardiographic variables of 36 patients (19 men, 58 ± 14 years) with HCM and an LVEF of ≥ 55%. Echocardiographic variables measured were LV wall thickness, end‐diastolic LV internal dimension (LVIDd) and volume (LVEDV), LV mass, and LV mass index (LV mass/body surface area, LVMI). Left ventricular outflow tract pressure gradient, transmitral E and A velocities, deceleration time (DT) of the transmitral E wave, and septal annular E' velocity were measured by Doppler technique. The relationship between echocardiographic variables and plasma NT‐proBNP level was analyzed. Results: The plasma NT‐proBNP level was 775.2 ± 994.2 pg/ml (range 33.1‐729.0 pg/ml). It showed positive correlations with LV end‐diastolic septal thickness (r = 0.39, p = 0.010) and LVMI (r = 0.27, p = 0.050), while it revealed negative correlations with LVIDd (r = −0.44, p = 0.004), LVEDV (r= −0.44, p = 0.004) and DT(r= −0.31, p = 0.034). The NT‐proBNP level was higher in the patients with than in those without LV diastolic dysfunction (p = 0.03 3) and was independently related to LVIDd (p = 0.001), LVMI (p = 0.006) and DT (p = 0.031) by multivariate analysis. Conclusion: In patients with HCM and normal LVEF, the amount of LV hypertrophy and LV diastolic dysfunction may exert a significant role in determining plasma NT‐proBNP level.