Vigorous response in plasma N-terminal pro-brain natriuretic peptide (NT-BNP) to acute myocardial infarction.

Acute myocardial infarction (MI) results in activation of neurohormonal systems and increased plasma concentrations of myocardial enzymes and structural proteins. We hypothesized that plasma levels of N-terminal pro-brain natriuretic peptide (NT-BNP) would respond more vigorously after MI than those of other natriuretic peptides. We also sought to compare this response with that of the established myocardial injury markers troponin T (TnT), myoglobin and creatine kinase MB (CK-MB). We obtained multiple blood samples for measurement of atrial natriuretic peptide (ANP), N-terminal pro-ANP, brain natriuretic peptide (BNP) and NT-BNP along with CK-MB, TnT and myoglobin in 24 patients presenting to the Coronary Care Unit within 6 h of onset of MI. Multiple samples were obtained in the first 24 h, then at 72 h, 1 week, 6 weeks and 12 weeks. NT-BNP increased rapidly to peak at 24 h and exhibited greater ( P <0.001) absolute increments from baseline compared with BNP and ANP, whereas NT-ANP did not change from baseline. Proportional increments in NT-BNP were also greater than those for the other natriuretic peptides ( P <0.05). Natriuretic peptide levels reached their peak around 24 h, later than peak TnT, CK-MB and myoglobin (peak between 1-10 h), and NT-BNP and ANP remained elevated on average for 12 weeks. Our present results, with detailed sampling of a cohort of acute MI patients, demonstrate greater absolute and proportional increments in NT-BNP than ANP or BNP with sustained elevation of these peptides at 12 weeks.