Background: Previous studies suggested that N-terminal pro-brain natriuretic peptide (NT-proBNP) level is a powerful independent predictor of death or heart failure (HF) when measured at admission in patients with chest pain or acute coronary syndrome. Little is known about the role of NT-proBNP level measured during a hospitalization for ST segment elevation myocardial infarction (STEMI) in predicting clinical outcomes. We evaluated the optimal NT-proBNP timing (admission, 72 hours, or delta [Δ] NT-proBNP [72 hours minus admission]) to predict 1-year new-onset HF in STEMI patients.
Methods: We measured NT-proBNP levels at admission and 72 hours in 72 patients with STEMI. HF events were adjudicated and defined as hospitalization for HF or need for new initiation of a loop diuretic at 1-year follow-up. Values are presented as medians and interquartile range or frequencies (%) as appropriate. Cox regression analysis was used to determine predictors of adverse events. A receiver-operative-curve was constructed to identify the discriminative value and optimal cut-off points for NT-proBNP.
Results: Patients (age 56 [49-64] years, males 59 [82%]) were followed for a median duration of 365 [180-365] days. HF events were recorded in 9 (12.5%) patients. NT-proBNP values at admission, 72 hours, and ΔNT-proBNP were 89 (26-268) pg/mL, 452 (223-1064) pg/mL, and 283 (68-686) pg/mL, respectively. NT-proBNP at 72 hours and ΔNT-proBNP, but not admission NT-proBNP predicted new-onset HF events at follow-up (P=0.03, P=0.002 and P=0.89, respectively). The optimal area under the curve of 0.771 (95%, CI [0.630-0.912], P= 0.009) and cut-off value of 830 pg/mL (sensitivity 79%; specificity 76%) were found for NT-proBNP at 72 hours. The Kaplan-Meier survival curves for NT-proBNP at 72 hours dichotomized above and below this cut-off value, confirmed NT-proBNP at 72 hours >830 pg/mL as predictive of HF events (log-rank statistic = 8.688, P=0.003).
Conclusions: NT-proBNP level at 72 hours and ΔNT-proBNP (72 hours minus admission), but not at time of admission, predicted HF events in patients following STEMI.