Clinical value of myeloperoxidase in early identification of acute coronary syndrome and in diagnosis of acute myocardial infarction

Objective To study the changing rule of myeloperoxidase (MPO) in acute coronary syndrome (ACS) and its clinical value in diagnosis of acute myocardial infarction (AMI). Methods Heparin anticoagulant plasma samples were taken from those undergoing physical examination, and from patients with unstable angina pectoris (UAP), AMI, autoimmune and inflammatory diseases. Their plasma MPO levels were measured by latex-enhanced turbidimetric immunoassay. Results The plasma MPO levels were significantly higher in patients with UAP, AMI and inf l ammatory disease than in those undergoing physical examination (P< 0.05).No significant difference was found in plasma MPO level between patients with autoimmunity disease and those undergoing physical examination (P> 0.05). The plasma MPO level was related with the plasma levels of HCY, CK, CRP, LDH and CTnI, r< 0.4, P< 0.05) but not with IMA (P> 0.05). The area under ROC for plasma MPO was 0.795 in patients with UAP (P=0.000), indicating that the accurate of plasma MPO level was moderate for the diagnosis of UAP. The area under ROC for plasma MPO was 0.911 in patients with AMI (P=0.000), indicating that the accurate of plasma MPO level was high for the diagnosis of UAP. The critical value of MPO was 149.2 ng/ml for the diagnosis of AMI in 111 patients (101 with positive MPO and 10 with negative MPO) and in 161 controls undergoing physical examination (56 with positive MPO and 105 with negative MPO) with a sensitivity of 91.3%, a specificity of 64.3%, an accuracy of 75.7%, a missed diagnosis rate of 8.7%, a misdiagnosis rate of 35.7%, a positive predicting rate of 65.2%, and a negative predicting rate of 91.0%. Kappa test showed that the plasma MPO level was consistent with the clinical diagnosis of AMI (P=0.000). Multivariate logistic regression analysis revealed that the R² for the AMI prediction modelestablished with MPO, LDH, HCY, IMA and age was 0.922 with a total correct rate of 96.80%. Conclusion MPO can effectively predict ACS and diagnose AMI.