Myeloperoxidase aids prognostication together with NT-BNP in high-risk patients with acute ST elevation myocardial infarction

Background: Inflammation plays a critical role in acute myocardial infarction. One such inflammatory marker is myeloperoxidase (MPO). Its role as a predictor of death or MI in patients with ST segment elevation myocardial infarction (STEMI) is unclear. We sought to investigate this and compared it to N terminal pro B type natriuretic peptide (NT-BNP). Method: We studied 384 post STEMI patients. Patients were followed-up for the combined endpoint of death or readmission with non-fatal MI. Results: There were 40 deaths and 37 readmissions with MI. Median MPO was raised in patients experiencing death or MI compared to survivors (median [range] ng/ml, 50.6[15.3-124.1] vs. 33.5[6.6-400.2], p=0.001). Using a Cox proportional hazards model log median MPO (HR 6.91, 95% CI: 1.79-26.73, p=0.005) and log median NT-BNP (HR 4.21, 95% CI: 1.53-11.58, p=0.005) independently predicted death or non-fatal MI. MPO had predictive power in both below and above median NT-BNP levels (log rank 5.60, p=0.020, log rank 5.12, p=0.024 respectively). The receiver-operating curve for median NT-BNP yielded an area under the curve (AUC) of 0.72 (95% CI: 0.65-0.79, p<0.001); for median MPO the AUC was 0.62 (95% CI: 0.55-0.69, p=0.001). The logistic model combining the 2 markers yielded an AUC of 0.76 (95% CI: 0.69-0.82, p<0.001). Conclusion: MPO and NT-BNP may be useful tools for risk stratification of all acute coronary syndromes, including higher risk STEMI patients.