B-type natriuretic peptide molecular forms for risk stratification and prediction of outcome after acute myocardial infarction

Background: B-type natriuretic peptide (BNP) is known to be a risk marker following acute myocardial infarction (MI). More recently, truncated molecular forms of the BNP molecule have been identified, with the association of these forms and outcome in acute MI not known. The present study investigated their use as risk stratifying biomarkers of this condition. Methods: BNP molecular forms (BNP 5-32, BNP 4-32 and BNP 3-32) were measured in plasma from 1,078 acute MI patients using immunocapture followed by MALDI-ToF-mass spectrometry. Associations of molecular forms with short-term and long-term adverse outcomes were assessed. Results: BNP molecular forms were independent predictors of mortality/reinfarction, mortality/rehospitalization due to heart failure, and a composite of all events at 6 months, 1 year and 2 years and showed prognostic ability comparable with conventional BNP measurements (P <0.001-0.026 vs. N-terminal [NT]-proBNP P <0.001-0.020, respectively). Reclassification analyses showed BNP molecular forms successfully reclassified patient risk when used in addition to the GRACE clinical risk score (P ≤0.005). BNP 5-32 showed utility as a secondary risk stratification biomarker when used in combination with the GRACE score and NT-proBNP by successful down-classification of high-risk patients. Conclusions: BNP molecular forms were associated with poor prognosis at 6 months, 1 year and at 2 years in patients with acute MI. BNP 5-32 showed successful utility as a secondary marker in combination with NT-proBNP after GRACE scoring. This study suggests a potential role for BNP molecular forms in prognosis and risk stratification after acute MI.