Early Interleukin-1 Receptor Antagonist Elevation in Patients with Acute Myocardial Infarction

OBJECTIVES: We sought to evaluate interleukin-1 receptor antagonist (IL-1Ra) levels in patients with ST-segment elevation acute myocardial infarction (AMI) upon emergency department (ED) admission in order to assess the sensitivity of such a determination by comparison with common markers of myocardial necrosis. BACKGROUND: Inflammatory markers are elevated in patients with unstable coronary syndromes, but IL-1Ra levels during the early phases of AMI have not been previously investigated. METHODS: Levels of IL-1Ra were measured in 44 consecutive patients with AMI and compared with creatine kinase (CK), CK-MB, troponin I, myoglobin, and C-reactive protein (CRP). RESULTS: Upon admission, 82% of patients had elevated (>230 pg/ml) IL-1Ra levels, compared with 41% of patients with raised CK (p = 0.001), CK-MB (45%, p = 0.002), troponin I (57%, p = 0.027), myoglobin (48%, p = 0.004), and CRP (57%, p = 0.019) levels. The IL-1Ra values were significantly higher in patients with heralded AMI than in those without pre-infarction angina (671 vs. 320 pg/ml, p = 0.013). The sensitivity of IL-1Ra determination increased to 86% when chest pain duration was S3 h and to 91% if heralded infarction occurred. CONCLUSIONS: Our study indicates that, unlike markers of necrosis, an increase of IL-1Ra levels occurs early in patients with AMI, is more significant in those with heralded infarction and symptom onset ≤3 h, and precedes the release of markers of necrosis. Thus, IL-1Ra determination may be an important early adjuvant toward the diagnosis of AMI in the ED.