Plasma brain natriuretic peptide/N-terminal pro-brain natriuretic peptide ratio reflects the severity of pulmonary infection in patients with heart failure

Eighty two heart failure (HF) patients were enrolled in the study, including 52 cases with pulmonary infection (infectious group) and 30 cases without pulmonary infection (noninfectious group). Plasma brain natriuretic peptide (BNP), N-terminal pro-brain natriuretic peptide (NT-proBNP) levels were measured and the correlation of plasma BNP, NT-proBNP and NT-proBNP/BNP with inflammatory markers (WBC count, CRP, PCT) and left ventricular ejection fraction (LVEF) was analyzed.Results show that NT-proBNP/BNP ratio in infectious group was significantly higher than that in noninfectious group (t=10.764, P 0.05); NT-proBNP and BNP levels were not correlated with inflammation markers and LVEF (P>0.05). In noninfectious group, NT-proBNP/BNP was not correlated with inflammation markers and LVEF (P>0.05), NT-proBNP and BNP were positively correlated with CRP and negatively correlated with LVEF (all P 0.05). Multiple linear regression analysis showed that NT-proBNP/BNP ratio had positive correlation with CRP in infectious group. The results reveal that in heart failure patients complicated with pulmonary infection, neither NT-proBNP nor BNP reflects the severity of heart failure or infection; but the NT-proBNP/BNP ratio can indicate the severity of infection independently. Key words: Natriuretic peptide, brain; Heart failure