The role of myeloperoxidase (MPO) for prognostic evaluation in sensitive cardiac troponin I negative chest pain patients in the emergency department

The diagnostic work-up of patients with acute chest pain in the emergency department (ED) is a challenging task. Serial troponin testing is required to rule-out acute myocardial infarction.

To evaluate the value of myeloperoxidase (MPO) testing in sensitive cardiac troponin I (cTnI) negative patients with suspected acute coronary syndromes (ACS) in the routine setting of an ED.

MPO was assessed in 432 consecutive patients presenting to the ED with ACS. In 266 patients, serial blood samples were available. After 6 weeks, major adverse cardiac events (MACE) were assessed. MPO and cTnI were measured in all available samples. For cTnI, a sensitive assay was used. Cut-off values were derived from an independent sample of 300 healthy volunteers.

Incidence of MACE in our population was 13%. MPO levels revealed sensitivity (Sens) of 82.1% and specificity (Spec) of 37.2% for MACE compared with 60.7% Sens and 61.4% Spec for sensitive cTnI. In serial sensitive cTnI negative patients (n=218), MACE incidence was 6.4%. MPO continued to demonstrate significant discriminatory power for the prognosis of MACE. Multivariate analyses confirmed these findings.

MPO has an independent prognostic value overall and most notably in patients tested negative with a higher sensitive cardiac troponin I assay. MPO could be a promising biomarker for the initial evaluation of patients in chest pain units and is worth further investigation.