Ischemia-modified albumin in differential diagnosis of acute coronary syndrome without ST elevation and unstable angina pectoris.

Background: Ischemia modified albumin (IMA) was registered by the United States Food and Drug Administration as a marker of myocardial ischemia.

Aim: To assess the usefulness of IMA measurement for differentiating patients with acute coronary syndrome (ACS) with no ST elevation and patients with unstable angina pectoris.

Methods: The study group consisted of 121 patients (mean age 63 +/- 12 years, 84 males), who were admitted to our department with retrosternal chest pain occurring at rest and lasting more than 20 minutes. The patients had laboratory tests performed including aspartate aminotransferase, izoenzyme of creatine kinase activity, troponin T, N-terminal pro-brain natriuretic peptide (NT-proBNP), C-reactive protein, IMA concentration and creatinine clearance. Coronary angiography was also performed. All study patients were divided into 2 groups: group I with elevated troponin concentration (58 patients) and group II with troponin concentration below reference value (63 patients).

Results: The IMA concentration in the serum did not differ significantly between group I (troponin positive) and group II (troponin negative) (95.2 +/- 12.8 U/mL vs 94.0 +/- 17.9 U/mL, NS). The percentage of patients with elevated IMA values (cut off point of 85 U/mL) did not differ significantly between group I and group II patients (76.6% vs 76.2%, NS). In patients from group I an upward trend was noted, whereas in patients from group II a downward trend was associated with the duration of ischemic chest pain. In group I the correlation between the IMA concentration and the NT-proBNP concentration was positive (R = 0.2957; p < 0.0316). The parameters differentiating patients from group I and group II were: left ventricular ejection fraction, leukocytosis, serum glucose concentration and creatinine clearance.

Conclusions: 1. The IMA concentration does not differentiate ACS patients without ST segment elevation myocardial infarction from patients with unstable angina. 2. The upward trend of IMA concentration was associated with the duration of chest pain in patients with ACS, whereas the opposite trend was found in patients with unstable angina pectoris.