Detection of left ventricular enlargement and impaired systolic function with plasma N-terminal pro brain natriuretic peptide concentrations

Background Brain- and N-terminal pro brain natriuretic peptide (NT-proBNP) have been identified as promising markers for heart failure. However, previous studies have revealed that they may hold insufficient diagnostic power for implementation into clinical practice because of a significant overlap in the range of plasma levels between healthy subjects and subjects with heart failure. We hypothesized that imprecision of the reference method lie, the echocardiographic evaluation of left ventricular [LV] function) may have affected results from those earlier studies. We therefore wanted to investigate the diagnostic potential of NT-proBNP with magnetic resonance imaging as the reference method for the cardiac measurements. Methods Forty-eight patients with stable symptomatic heart failure in New York Heart Association functional classifications II to IV were examined once with blood samples and magnetic resonance imaging along with 20 age-matched and gender-matched healthy control subjects. Results NT-proBNP was associated with LV end-diastolic (r = 0.69; P < .0001) and end-systolic (r = 0.73; P < .0001) volume indices, LV mass index (r = 0.69; P < .0001), and LV ejection fraction (r = -0.75; P < .0001). Receiver operating characteristic curves were calculated for the ability of NT-proBNP to detect LV end-diastolic volume index (>105 mL.m(-2)[cut-offl; sensitivity/specificity, 82%/87%), LV end-systolic volume index (>35 mL.m(-2); sensitivity/specificity, 86%/86%), LV mass index (>152 g.m(-2); sensitivity/specificity, 85%/86%), and LV ejection fraction (<58%; sensitivity/specificity, 84%/85%) deviating more than 2 standard deviations from control values. Conclusion NT-proBNP is a powerful marker for LV dimensions and systolic function in patients with heart failure and discriminates well between healthy subjects and subjects with impaired LV systolic function or increased LV dimensions.