The role of plasma N-terminal brain natriuretic pro-peptide in diagnosing elderly patients with acute exacerbation of COPD concurrent with left heart failure

Introduction: Acute exacerbation of COPD (AECOPD) and left heart failure (LHF) commonly exist together in clinical practice. However, the identification of AECOPD concurrent with LHF is currently challenging. Our study aimed to investigate the role of plasma N-terminal brain natriuretic pro-peptide (NT-proBNP) in diagnosing elderly patients with AECOPD associated with LHF. Methods and results: LHF was diagnosed in patients with AECOPD according to echocardio-graphic criteria, and the levels of NT-proBNP in plasma were measured by quantitative electro-chemiluminescence assay. Among the 655 patients with AECOPD, 158 (24.1%) had comorbid LHF, whether systolic (n=108, 68.4%) or diastolic (n=50, 31.6%). The plasma concentrations of NT-proBNP in elderly patients with AECOPD associated with LHF were markedly elevated, compared with those with only AECOPD (4,542.5 and 763.0 ng/L, respectively, P < 0.01). The receiver operating characteristic curve indicated a diagnostic cutoff value of 1,677.5 ng/L of NT-proBNP in plasma for ascertaining the presence of LHF in AECOPD, with a sensitivity of 87.9%, a specificity of 88.5%, and an accuracy of 88.4%. Conclusion: The plasma level of NT-proBNP may be a useful indicator in diagnosing AECOPD associated with LHF.