Diagnostic efficacy of myeloperoxidase for the detection of acute coronary syndromes.

BACKGROUND Early diagnosis of acute coronary syndrome (ACS) is frequently a challenging task, while immediate risk stratification remains crucial for the prompt implementation of appropriate therapy in this setting. Employing markers that increase rapidly after the symptom onset may enhance triage and therapeutic decision-making in patients suspected for ACS. Myeloperoxidase (MPO) exerting proinflammatory and pro-oxidative properties is suggested as a reliable early marker for ACS associated with unfavourable clinical outcome. We assessed the diagnostic efficacy of plasma MPO alone or in combination with cardiac troponin I (cTnI) for detecting ACS in patients presenting with chest pain initiating within 6h before the hospital admission. MATERIAL AND METHODS A study group consisted of 253 patients diagnosed with ACS and 47 subjects having other heart disease or unspecified chest pain. Clinically healthy volunteers (n=124) served as controls. MPO concentration was measured in plasma (Abbott Diagnostics, USA), while serum was assayed for cTnI, creatine-kinase MB, lipids, glucose, creatinine, brain natriuretic peptide type B and C-reactive protein. RESULTS Both MPO and cTnI values were significantly lower in non-ACS subjects than in patients with ACS. At 97·5th percentile as cut-off, the superiority of MPO over cTnI was observed in patients with unstable angina and non-ACS subjects. Considerably higher MPO concentrations were demonstrated in the troponin-negative ACS patients on admission who became troponin-positive after 6h. Combined evaluation of MPO and cTnI possessed remarkably higher sensitivity than assessment of cTnI alone in all patients with ACS. CONCLUSIONS Myeloperoxidase substantially facilitates the early diagnosis of ACS.