Ischaemia modified albumin in patients with acute coronary syndrome and negative cardiac troponin I

BACKGROUND: Approximately 40-60% of patients with acute coronary syndrome (ACS) have normal cardiac troponin I (cTnI) concentrations on admission. Ischaemia modified albumin (IMA) has been suggested as a new biomarker of myocardial ischaemia. METHODS: A total of 43 patients presenting with symptoms suggestive of ACS but with normal (< 0.1 μg/L) cTnI concentrations and 45 healthy subjects were studied. The patients from the study group were divided into two groups: STEMI (n = 28) and NSTEMI (n = 15). All these patients were undergoing percutaneous coronary intervention (PCI) with stenting. The concentrations of cTnI, myoglobin and IMA were determined on admission and 4 h after PCI. RESULTS: Mean (SD) IMA concentrations were higher in patients with ACS (114.39 ± 25.18 U/ml) as compared to the control group (96.24 ± 6.28 U/ml, p < 0.005). IMA concentrations ≥ 104.0 U/ml demonstrated 72.1% sensitivity and 75.6% specificity for the diagnosis of ACS. The area under the receiver operator characteristic curve was 0.766 (95% CI 0.664-0.868) for ACS patients (NSTEMI + STEMI). In both groups increased median (IQR) cTnI concentration after PCI was observed (STEMI patients to 65.4 (10.9-106.9) μg/L and NSTEMI to 17.6 (0.77-84.0) μg/L). In contrast, no increase in IMA concentration was observed. CONCLUSIONS: IMA may be a useful biomarker for the identification of ACS patients presenting with typical acute chest pain and/or abnormal electrocardiograms but negative cTnI.