Sequential Analysis of Myeloperoxidase for Prediction of Adverse Events After Suspected Acute Coronary Ischemia

Abstract

Background: Myeloperoxidase (MPO) plasma values predict major adverse cardiac events (MACE) in cases of acute coronary syndrome. The effect of serial testing in patients who are suspected for acute coronary ischemia is unclear. Hypothesis: We hypothesize that sequential MPO measurement may improve prediction of MACE in patients with suspected acute coronary ischemia. Methods: The present prospective observational study examined the prognostic significance of MPO in 917 patients with suspicion of acute coronary syndrome. Blood samples were taken at cardiac catheter laboratory admission and the day after coronary angiography. We recorded patients' mortality, the occurrence of cardiac ischemia, and repeated percutaneous coronary intervention through the next 6 months. Results: Mortality among patients with increased MPO plasma levels the day after coronary angiography was increased significantly (P < 0.01). Patients with MPO values above 306.3 pmol/L had a significantly higher incidence of 6-month MACE (P < 0.0001) than patients with lower plasma values. Cox proportional hazards multivariate regression analyses revealed that MPO was an independent marker for MACE after suspected acute coronary ischemia (P = 0.048). However, MPO plasma levels at cardiac catheter laboratory admission showed no prognostic significance. Conclusions: In patients with suspected myocardial infarction, MPO levels above 306.3 pmol/L measured 24 hours after onset of symptoms were independent predictors of 6-month mortality and MACE.

Prognostic Role of Elevated Myeloperoxidase in Patients with Acute Coronary Syndrome: A Systemic Review and Meta-Analysis

“…Myeloperoxidase as a prognostic marker in ACS patients has generated conflicting results in clinical studies. The majority of clinical data has confirmed the prognostic value of MPO in predicting mortality [9, 26–29], and our analysis confirmed this correlation to be highly significant. However, although there was strong correlation between MPO levels and other clinical events such as MACE and recurrent myocardial infarction, this association did not reach statistical significance in individual trials or our analysis [9, 30, 31].…”

“…In accordance with these findings, we found that the prognostic value of MPO was the highest among studies with high proportion of AMI patients [10, 27] compared to those with higher percentage of unstable angina subjects [29, 34]. Additionally, timing of sample collection could have played a role in the variable results since MPO level was significantly higher immediately after STEMI [26, 35]. Although studies adopted different MPO cutoff values, our analysis was primarily focused on the prognostic value of MPO rather than its absolute value since the included studies used different MPO assays.…”

Neutrophil degranulation and myocardial infarction

“…Higher MPO predicted worse cardiac outcomes and lower ejection fraction [ 46 , 47 ], indicating higher long-term mortality [ 48 ]. Koch et al [ 49 ] presented that greater than 306.3 pmol/L of MPO measured 24 h after the onset of symptoms was an independent predictor of 6-month mortality and major adverse cardiac events in patients with suspected MI. Rudolph et al [ 45 ] showed that MPO was a predictive marker of increased risk of adverse events at 30 days and 6 months in patients admitted with ACS.…”

Effect of collection tube type and freeze–thaw cycles on myeloperoxidase concentrations in blood samples of acute coronary syndrome patients

“…19,21 Preclinical blood sample collections before the administration of heparin could be an option for generating valid data. 22 Different studies have reported diverse results for correlations between MPO concentrations determined in different types of samples. A good positive correlation was reported by Wendland et al 17 between MPO concentrations for heparin and serum samples (r ¼ 0.79), but no correlation was seen between EDTA and heparin samples (r ¼ 0.21).…”