How are myeloperoxidase (MPO) cardiac markers characterized and what do they indicate?

Updated: Jul 30, 2021
  • Author: Kamal (Komo) Gursahani, MD, MBA; Chief Editor: Barry E Brenner, MD, PhD, FACEP  more...
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Myeloperoxidase (MPO) is a proinflammatory enzyme that generates reactant oxidant species and has been linked to prothrombotic oxidized lipid production, plaque instability, lipid-laden soft plaque creation, and vasoconstriction from nitrous oxide depletion. Early studies showed significantly increased MPO levels in patients with angiographically documented coronary artery disease [78] ; these findings spurred further investigation into MPO as a novel cardiac marker.

In 604 sequential patients presenting to an ED with chest pain, elevated MPO levels independently predicted an increased risk for major adverse cardiac events, including myocardial infarction (MI), reinfarction, need for revascularization, or death at 30 days and at 6 months. [79] Among the patients who presented to the ED with chest pain but who were ultimately ruled out for MI, an elevated MPO level at presentation predicted subsequent major adverse cardiovascular outcomes. In a subgroup of patients with negative baseline troponin T (TnT), MPO levels were significantly elevated at baseline, even within 2 hours after symptom onset. [79]

MPO may be a useful early marker in the ED based on its ability to detect plaque vulnerability that precedes ACS. However, further validation studies on MPO in the general ED chest pain population are needed to determine its sensitivity and specificity, as well as its negative and positive predictive values. [80, 81]

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