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 less than or equal to3 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 less than or equal to3 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.