Introduction: Brain natriuretic peptide (BNP) correlates well with left ventricular wall hypertrophy and the severity of left ventricular outflow tract (LVOT) obstruction in patients with hypertrophic cardiomyopathy (HCM). The purpose of this study was to investigate the correlation of BNP levels with clinical status and left ventricular function in HCM patients.
Methods: In 32 patients with HCM (age 58 +/- 14 years) we evaluated: (a) the severity of dyspnea and angina; (b) BNP plasma levels; (c) left ventricular wall thickness, sphericity index and mitral regurgitation; (d) LVOT obstruction; (e) ejection fraction; (f) left ventricular diastolic function, global and regional, by tissue Doppler imaging.
Results: BNP plasma levels correlated positively with dyspnea (r = 0.460, p < 0.001), angina (r = 0.460, p = 0.008), mitral regurgitation (r = 0.600, p < 0.001), thickness of interventricular septum (r = 0.526, p = 0.002), and LVOT obstruction (r = 0.551, p = 0.001 and r = 0.603, p < 0.001 for latent obstruction), while they were negatively correlated with left ventricular sphericity index (r = -0.368, p = 0.038). BNP plasma levels were strongly correlated with E/Vp and E/Eal (Vp: flow propagation velocity, Eal: E on the lateral side of the mitral annulus), representing the left ventricular filling pressures, and with some other parameters of regional diastolic function: Ams (A at the mid-segment of the interventricular septum) r = -0.518, p = 0.002; Aas (A on the septal side of the mitral annulus) r = -0.454, p = 0.009; Aal (A on the lateral side of the mitral annulus) r = -0.467, p = 0.007. From multiple regression analysis, angina and the ratio E/Eal were the strongest predictors of BNP plasma levels.
Conclusions: BNP plasma levels in HCM patients can be used as an adjunctive objective method of evaluating cardiac dysfunction through their correlation with angina and left ventricular filling pressures.