Impact of myeloperoxidase dosage in acute coronary syndrome

Background

The leukocyte enzyme myeloperoxidase has been linked to the development of lipid-laden soft plaque, the activation of protease cascades affecting the stability and thrombogenicity of plaque in acute coronary syndromes. A recent study showed its potential usefulness for risk stratification among patients who present with chest pain.

Objective

To determine whether measurement of myeloperoxidase can predict acute myocardial infarction in patients admitted to a chest pain unit.

Methods

From July to December 2004, we conducted a prospective observational cohort study in 140 patients presenting to the emergency department within 24 hours after the onset of chest pain of suspected cardiac origin. Subjects who were at least 21 years old and with no history or clinical evidence of inflammatory, immunological or neoplasic disease were eligible to participate. The demographics, clinical profile and outcomes were recorded. Admissional myeloperoxidase was measured and correlated with clinical outcome.

Results

The study population consisted of 140 patients (54% male); mean age 63.7 ± 13.9 years, 62.8% with systemic hypertension and 27.8% were diabetics. Myocardial infarction was the final diagnoses in 9.3% of patients. A cutoff point of 100 pM was selected with the use of the C statistical method. This cutoff point showed a sensitivity of 92%, a negative predictive value of 98%, a negative likelihood ratio of 0.19 and an odds ratio of 8.1 (P = 0.031). By multiple regression including other conventional risk factors, this level of admission myeloperoxidase was identified as an independent predictor of myocardial infarction (odds ratio of 8.0; P = 0.048).

Conclusion

Myeloperoxidase measured soon after admission due to chest pain is a new risk marker for acute coronary syndromes. Its usefulness as a strong independent predictor for acute myocardial infarction must be considered.