Objective We tested the hypothesis that the plasma levels of fibrinogen and macrophage inflammatory protein (MIP)-1βare synergistic predictive markers of the prognosis of intermediate coronary artery lesions.Methods A prospective study was performed on 670 patients with intermediate coronary artery lesions.Fibrinogen and MIP-1βwere measured.Major adverse cardiac event (MACE) was defined as a composite of cardiovascular death,nonfatal myocardial infarction, revascularization and readmission due to angina pectoris.Results During follow-up, 72 events occurred; 5 patients died, 7 patients suffered a nonfatal myocardial infarction, 11 patients underwent revascularization and 49 patients were readmitted for angina pectoris.In patients with above-median levels of MIP-1β, a 2.62-fold risk of a MACE [95% confidence interval (CI) 1.53-4.48] was predicted compared with patients with below-median levels of MIP-1β.However, the strongest risk prediction was achieved by assessing MIP-1βand fibrinogen together.After adjusting for traditional risk factors, a multivariate Cox proportional hazards analysis showed that patients with both MIP-1βand fibrinogen above the median had a 4.37-fold risk of a MACE (95% CI 1.89-10.11).Conclusion MIP-1βaccurately predicted MACEs.Considering MIP-1βand fibrinogen together may improve long-term risk assessment.These two biomarkers have a synergistic effect for assessing long-term risk in patients with intermediate coronary artery lesions.