Interleukin-18: an independent predictor of cardiovascular events in patients with acute coronary syndrome after 6 months of follow-up.

BACKGROUND: Interleukin-18 (IL-18), a proinflammatory cytokine, has been associated with atherogenesis and plaque rupture in acute coronary syndrome (ACS). Recent studies suggest that IL-18 may have a long-term prognostic value. The aim of this study was to evaluate the relationship between IL-18 levels and major adverse cardiovascular events within 6 months of follow-up in post-ACS patients. METHODS: One hundred and twelve consecutive patients admitted to a university hospital with ACS were included in the study. IL-18 and C-reactive protein were measured within the first 24 h of admission. Six months after hospital discharge, the incidence of major adverse cardiovascular events (cardiovascular death, new episode of ACS, and need for unplanned revascularization) was assessed. RESULTS: Mean age of patients was 64 +/- 11 years, and 58 (52%) were male. During the 6 months of follow-up, 33 patients (31.4%) experienced major adverse cardiovascular events. Median IL-18 serum levels were higher among patients who had events than among those who did not: 271.7 pg/ml (interquartile range: 172.9-389.6) and 139.7 pg/ml (interquartile range: 99.9-265.7), respectively (P < 0.01). In the Cox multivariate analysis, after adjustment for clinical risk factors and serum troponin, elevated levels of IL-18 were associated with higher incidence of events (hazard ratio: 2.5; 95% confidence interval: 1.14-5.52; P = 0.023). In this population, C-reactive protein was of borderline significance for events. CONCLUSION: Serum IL-18 levels in ACS patients were independent predictors of long-term cardiovascular events. These findings support the association between inflammation and prognosis of ACS patients, as well as the clinical impact of this biomarker.