A total of 127 patients with ACS were enrolled, including 49 patients with unstable angina pectoris(UAP), 40 patients with ST elevation acute myocardial infarction (STEMI) and 38 patients with non-ST elevation acute myocardial infarction (NSTEMI). In the same period, 60 healthy controls were enrolled. The cTnI concentration in patients with ASC for the first-time determination and IMA concentration by enzyme-linked immunosorbent assay (ELISA) to detect the same sample retrospectively were taken.

Compared with control group, IMA concentrations in UAP, STEMI and NSTEMI groups were higher (P<0.05), those in STEMI and NSTEMI groups increased compared with that in UAP group (P<0.05), and that in STEMI group significantly increased compared with that in NSTEMI group (P<0.05). The cTnI comcentrations in STEMI and NSTEMI groups were higher than that in UAP group (P<0.05), that in STEMI group had no difference with that in NSTEMI group (P>0.05). IMA and cTn Ⅰ expression existed positive correlation (r=0.536,P<0.05). Receiver operating characteristic (ROC) curve showed the area under the ROC curve of IMA in the diagnosis of ACS was 0.87±0.028, the corresponding sensitivity 92%, the specificity 78%, while the area under the ROC curve for cTnI was 0.74±0.021, the corresponding sensitivity 77%, the specificity 91%, and there was statistical significance (P<0.05).

IMA and cTnI assays for the diagnosis of myocardial infarction has important clinical value, and IMA diagnosis compared with cTnI is more ideal.