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

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. 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. 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. 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.