Abstract 569: NT-proBNP is an Important Independent Predictor of Clinical Events after Primary PCI for STEMI

Abstract

Acute myocardial infarction with ST-segment elevation (STEMI) remains a major global public health issue. Despite advances in therapy, patients remain at risk for death, repeat myocardial infarction (MI) shock and heart failure (HF). Novel markers that predict those at risk are needed. We studied 903 STEMI patients in The Assessment of Pexelizumab in Acute Myocardial Infarction trial (which enrolled STEMI patients presenting < 6 hrs of symptom onset who were to undergo primary PCI) in a case-control design (cases selected based on the trial’s primary composite outcome - death, shock or HF - and matched on age, gender and infarct location to controls). NT-proBNP (pg/ml) was measured at randomization and 24 hrs. Outcomes (individually and the composite) of death, shock, and HF at 90 days were examined by quartiles of NT-proBNP. A CART model was used to categorize adjusted risk. NT-proBNP was higher in patients who had events. Patients with higher NT-proBNP levels at baseline (median symptom onset to randomization 2.7 hrs) and 24 hrs had more events (composite p<0.001; death p<0.0001; HF p<0.0001; shock p=0.05) - See figure . Using the CART model (adjusted for age, gender and infarct location), baseline Killip class and NT-proBNP could further subcategorize patients into 90 day mortality categories 4%, 10%, 30%, and 53%. In fact, only 4 patients (1%) with a 24 hour NT-proBNP <999 pg/ml had any event in the next 90 days. Although the overall prognosis in STEMI patients undergoing primary PCI is good, NT-proBNP performed early and at 24 hrs provides important prognostic information for predicting negative outcomes i.e. shock, heart failure and death. Figure. Kaplan-Meier curve for the primary composite outcome stratified by baseline NT-proBNP (a), or 24 hour NT-proBNP (b).