Background: Elevated B-type natriuretic peptide levels in patients with acute myocardial infarction are useful in the prediction of poor outcome. It is still not established how often and when assessment of neurohormonal activation provides the best prognostic information.
Aim: To evaluate whether repeated measurements of B-type natriuretic peptide provide additional clinical information in patients with first ST-elevation myocardial infarction.
Methods: In 96 consecutive patients with first ST-elevation myocardial infarction, treated with primary percutaneous coronary intervention, B-type natriuretic peptide concentrations were measured twice: on admission and 24 hours later. A clinical composite endpoint was assessed during hospital stay.
Results: The median B-type natriuretic peptide concentration obtained on admission was 62.9 pg/mL and 24 hours later was 223.6 pg/mL. Thirty-five patients (36.4%) reached composite endpoint, including 3 deaths (3.1%). Both B-type natriuretic peptide levels were related to the clinical and echocardiographic variables, which refer to the large infarct expansion and acute left ventricular dysfunction. The first measurement was better correlated with current patient status (ie, TIMI Risk Score, admission Killip class). B-type natriuretic peptide 24 hours after admission was significantly higher in patients who had an adverse cardiovascular event during hospitalization (P = 0.02). ROC analysis also identified the second B-type natriuretic peptide measurement as significant to estimate adverse outcome (c = 0.64 CI 0.527 - 0.756 P = 0.007).
Conclusions: Despite there being a time interval of only 24 hours between the two sets of B-type natriuretic peptide sampling, both measurements provide important and different information. Only B-type natriuretic peptide measurement 24 hours after admission identifies patients with a high in-hospital event rate risk.