Prognostic Value of Serial N-Terminal Pro-Brain Natriuretic Peptide Testing in Patients With Acute Myocardial Infarction

Abstract

Natriuretic peptides (NPs) are important predictors of outcomes in patients with acute myocardial infarction (AMI) but can change over time. The association of patterns of NP changes after AMI on outcomes is less clear. We measured N-terminal pro-brain natriuretic peptide (NT-proBNP) during the AMI admission and at 1month in a prospective AMI registry. Outcomes included 1-year readmission and 2-year mortality. An elevated NT-proBNP was defined using age-specific criteria. Patients were classified into 3 groups (low/low [referent group], high/low, high/high) based on NT-proBNP value at enrollment and 1month. The incremental predictive value of NT-proBNP was determined after adjusting for 6-month GRACE risk score, diabetes, and ejection fraction <40%. Among 773 patients, 303 (38%) were low/low, 240 (30%), and were high/high, 230 (29%) were high/low. Two-year mortality was highest in high/high patients but similar in the high/low and low/low patients (13.1% vs 2.7% and 2.3%, respectively). Similarly, readmission was significantly more likely in the high/high versus the high/low and low/low groups. After adjustment, mortality was significantly higher in the high/high group (hazard ratio 4.02, 95% CI 1.67 to 9.66) compared with the low/low group, although readmission was no longer statistically different (hazard ratio 1.37, 95% CI 0.93 to 2.03). In conclusion, a persistently elevated NT-proBNP assessed 1month after discharge was associated with a higher risk of mortality in patient with AMI. Postdischarge risk stratification using NT-proBNP has the potential to identify higher risk patients after AMI.