Abstract 2618: Use of Myeloperoxidase in Chest Pain Evaluation in The Emergency Department
Background Elevated levels of myeloperoxidase (MPO) have been reported to indicate adverse outcome in selected patients with chest pain and acute coronary syndrome (ACS) but no data exists on its value in the routine setting of an emergency department (ED).
Patients and methods Initial MPO was assessed at admission in 432 consecutive patients presenting to the ED who were evaluated for an acute coronary syndrome. In a subset of 116 patients blood samples were also available after 6 and 12–36 hours. All patients were followed up for six weeks with respect to major adverse cardiac events (MACE) including death, re-admission for heart failure or ACS and unplanned repeat coronary revascularisation. MPO was measured using a fully automated immunoassay in development on the ARCHITECT® platform and its prognostic power was compared with serial cardiac troponin I using cut-offs of 198 pmol/L for MPO and 0.1 μg/L for troponin I.
Results Incidence of MACE was 13% in this population. MPO was detectable in all samples with a median of 246.5 (range 18 – 4547) pmol/L at admission. MPO increased significantly after 6h and decreased again after 12–36h. In this low-risk population, initial MPO levels revealed a sensitivity (Sens) of 82.1% and a specificity (Spec) of 37.5% (p<0.0001) for MACE compared with 28.6% Sens and 81.1% Spec (p=0.09 n.s.) for initial troponin I. Sensitivity of both markers improved when available serial information was used (MPO: Sens 96.4, Spec 22.6, p<0.0001; troponin I: Sens 44.6%, Spec 76.1%, p<0.01). In serial troponin I negative patients (n=317), both, initial MPO (Sens 80.6%, Spec 42.7%, p<0.05) and serial MPO (Sens 93.5%, Spec 28.7%, p<0.01) still demonstrated significant discriminatory power.
Conclusions MPO has independent prognostic value in unselected patients evaluated for ACS in the ED. However MPO levels vary widely over the first 24h hours and also lack specificity.