Objective: To examine the relation between plasma concentrations of interleukin-18 (IL-18), the interferon gamma inducing factor, and clinical instability of coronary artery disease.
Design and setting: Observational study in a university hospital.
Patients: 11 patients with unstable angina and negative troponin I, 21 patients with acute non-Q wave myocardial infarction (MI), 21 patients with acute Q wave MI, 9 patients with stable angina, and 11 controls.
Main outcome measures: Plasma IL-18 concentrations and their relation to clinical instability and myocardial dysfunction.
Results: Plasma concentrations of IL-18 were significantly increased in the unstable angina and MI groups in comparison with the stable angina and control groups (p < 0.01). No difference in IL-18 concentrations were found between patients with unstable angina, patients with non-Q wave MI, and patients with Q wave MI. Plasma IL-18 concentrations significantly correlated with decreased left ventricular ejection fraction (p = 0.01).
Conclusions: Plasma IL-18 concentrations are increased in patients with acute coronary syndromes and correlate with the severity of myocardial dysfunction.