The aim of this study was to determine the gene expression and protein levels of interleukin‐33 (IL‐33), fetuin A and cytokeratin 18 (CK‐18) in the pericardial fluid (PF) and plasma of patients with coronary artery disease (CAD) undergoing coronary artery bypass grafting (CABG). This evidence concerns the gene IL33 and coronary artery disorder.