BACKGROUNDAcute myocardial infarction (AMI) is a common cardiac emergency with high mortality. Serum soluble ST2 (sST2) is a new emerging biomarker of cardiac diseases. The present study is to investigate the predictive value of sST2 and interleukin-33 (IL-33) for risk stratification and prognosis in patients with AMI.

METHODSFifty-nine patients with AMI, whose chief complaint was chest pain or dyspnea, were selected for our study. Physical examination, chest radiograph, electrocardiograph (ECG), biomarkers of myocardial infarction, NT-proBNP, echocardiography and other relevant examinations were performed to confirm the diagnosis of AMI. Thirty-six healthy people were chosen as the control group. Serum samples from these subjects (patients within 24 hours after acute attack) were collected and the levels of sST2 and IL-33 were assayed by enzyme-linked immuno-sorbent assay (ELISA) kit. The follow-up was performed on the 7th day, 28th day, 3rd month and 6th month after acute attack. According to the follow-up results we defined the end of observation as recurrence of AMI or any causes of death.

RESULTSMedian sST2 level of the control group was 9.38 ng/ml and that of AMI patients was 29.06 ng/ml. Compared with the control group, sST2 expression in the AMI group was significantly different (P < 0.001). In contrast, the IL-33 level showed no significant difference between the two groups. Serum sST2 was a predictive factor independent of other variables and may provide complementary information to NT-proBNP or GRACE risk score. IL-33 had no relationship to recurrence of AMI. Both sST2 and the IL-33/sST2 ratio were correlated with the 6-month prognosis; areas under the ROC curve were 0.938 and 0.920 respectively.

CONCLUSIONSEarly in the course (<24 hours) of AMI, sST2 usually increases markedly. The increase of sST2 has an independent predictive value for the prognosis in AMI patients and provides complementary information to NT-proBNP or GRACE risk score. The IL-33/sST2 ratio correlates with the 6-month prognosis of AMI patients. However, there is no significant relationship between IL-33 and the prognosis of AMI patients.