Prognostic significance of interleukin-6 measurement in the diagnosis of acute myocardial infarction in emergency department.

BACKGROUND: Markers of inflammation may predict both coronary artery disease (CAD) and adverse outcomes in patients with known CAD. Here, we investigated the role of interleukin-6 (IL-6) in the "triage" and risk assessment of patients admitted to emergency department (ED).

METHODS: Serum IL-6 and high sensitivity C-reactive protein (hs-CRP) levels were prospectively evaluated in 88 patients with a history of precordial chest pain or shortness of breath of recent onset (<6 h).

RESULTS: Of the 88 patients, 21% were discharged from the ED with diagnosis of non-ischemic chest pain (NICP), 39% had a final diagnosis of unstable angina (UA) and 40% experienced an acute myocardial infarction (AMI). Median IL-6 (p<0.001) and hs-CRP (p<0.01) levels on admission were significantly increased in patients with AMI compared with patients with NICP or UA. IL-6 levels correlated with hs-CRP (p<0.01). Multivariate analyses including known risk factors showed that elevated creatine kinase-MB (p<0.05) and IL-6 levels (p<0.01) were independently associated with a final diagnosis of AMI. Elevated IL-6 levels significantly predicted the risk of AMI (OR=2.47, p=0.006) in chest pain-enzyme negative patients.

CONCLUSIONS: IL-6 may behave as an adjunctive diagnostic tool to assist in the risk assessment of enzyme-negative patients with precordial chest pain of recent onset.