Background: The prognostic value of interleukin (IL)-18 in patients with ST-segment elevation acute myocardial infarction (STEMI) is currently unclear. Thus, the purpose of this study was to test whether the circulating IL-18 level can predict prognosis in patients with STEMI undergoing primary percutaneous coronary intervention (PCI).
Methods and results: A prospective cohort study was conducted with 267 consecutive patients with STEMI of onset <12 h who were undergoing primary PCI. Blood samples for plasma IL-18 level were collected in the catheterization laboratory following vascular puncture. The plasma IL-18 level was also evaluated in 25 healthy and 30 at-risk control subjects. The plasma level of IL-18 was significantly higher in acute myocardial infarction (AMI) patients than in both groups of control subjects (all p<0.0001). Patients with high plasma IL-18 level (> or =560 pg/ml) had significantly higher peak creatine kinase-MB levels, higher incidence of cardiogenic shock upon presentation, significantly lower left ventricular ejection fraction (LVEF), lower successful reperfusion and significantly higher incidence of 30-day composite major adverse clinical events (MACE) (advanced congestive heart failure > or = class 3 or 30-day mortality) than those patients with low plasma IL-18 level (<560 pg/ml) (all p<0.0001). Multiple stepwise logistic regression analysis demonstrated that high plasma IL-18 level (> or =560 pg/ml) along with low LVEF (<50%) and cardiogenic shock were the most independent predictors of 30-day MACE (p<0.0001).
Conclusions: In patients with STEMI, plasma IL-18 level is a major independent inflammatory predictor of 30-day MACE. Evaluation of circulating IL-18 might improve the prediction of unfavorable clinical outcomes following AMI.