Ischemia-modified albumin (IMA) in differential diagnosis of transient myocardial ischemia from non ischemic chest pain

Abstract

Background: Early diagnosis of acute coronary syndrome (ACS) is an important factor in reducing mortality of this disease. Cardiac troponins are not elevated within first hours. So there is a need to optimize the clinical applicability and accuracy of novel ACS markers, particularly with regard to utilizing this technique in combination with other diagnostic methods. Methods: In this prospective study, we examined 226 patients between July 2009 and March 2010, admitted with chest pain to emergency room (ER). The study groups constisted of 120 subjects presenting with chest pain whose initial and subsequent diagnosis was unstable angina (UA), and 106subjects whose initial diagnosis was unstable angina but subsequent diagnosis was non ischemic chest pain(NICP). For each patient electrocardiogram(ECG),cardiac troponins (cTnT),creatinine phosphokinase(CPK), IMA levels were measured. We used McNemar's test for correlated proportions and logistic regression and ROC curve for achieving better result. Results: In this study median IMA values were definitely higher in patients with ACS compared with non ischemic chest pain (NICP) (p < 0.0001) (83.5 to 49.6). An IMA cut-off threshold derived from the receiver operating characteristics curve (ROC) was 85U/ml and gives 54 % (95%CI 51 to 56) sensitivity and 87 % (95%CI83 to 92)specificity in our population. Negative predictive value was 62 % (95%CI 59 to 66). When IMA and ECG and cTnT were considered together sensitivity was 97.5 % and specificity was 63 %, respectively. Conclusion:Ischemia-modified albumin did not provide superior sensitivity or specificity compared with other diagnostic tests.