Molecular ratio of mature B‐type natriuretic peptide in acute heart failure: an indicator for ventricular contractile recovery

AIMS: The methodology to distinguish between the heart failure (HF) with recovered ejection fraction (HFrecEF) and those with continuously reduced ejection fraction (EF) (HFcrEF) on admission has not been established. We recently demonstrated that the ratio of plasma levels of pro‐B‐type natriuretic peptide (proBNP) to total BNP (proBNP plus mature BNP) is decreased on admission in patients with mild acute HF, but not in severe acute HF as a compensatory mechanism for activating cyclic GMP via increases of bioactive mature BNP. We aimed to test the hypothesis that the ratio of bioactive mature BNP to total BNP is associated with reverse remodelling capacity in patients with HF with reduced EF. METHODS AND RESULTS: Plasma proBNP and total BNP were measured in patients with acute decompensated HF by using specific and sensitive enzyme immunochemiluminescent assay. Estimated percent mature BNP (%emBNP) was calculated as ([total BNP − proBNP]/total BNP) × 100. We retrospectively identified the patients with reduced EF (≤40%, on admission) who had echocardiographic data after discharge (n = 93). We defined patients with increased EF by >10% during the follow‐up term (median, 545 days) after the admission as HFrecEF group. We compared patient characteristics, %emBNP, and other biomarkers between HFrecEF and HFcrEF. Of the enrolled patients with HFrecEF (n = 32) and HFcrEF (n = 61), on admission, %emBNP was significantly higher in HFrecEF than in HFcrEF (44.1% vs. 36.9%; P < 0.05). There were no significant differences in left ventricular EF on admission between the two groups. The univariate analysis revealed that %emBNP on admission was associated with HFrecEF occurrence rate (P < 0.05), in contrast both total BNP and high‐sensitive cardiac troponin‐T levels were not associated with HFrecEF occurrence rate. CONCLUSIONS: The ratio of mature BNP to total BNP in plasma at the time of hospital admission may be predictive of left ventricular contractile recovery. Preservation of the capacity to convert proBNP to mature BNP, but not myocardial injury itself, is associated with future ventricular contractile recovery.