This study aims to investigate Stromal Cell-Derived Factor 4 (SDF4) levels and thiol/disulfide homeostasis in the blood and pericardial fluid of patients with established coronary artery disease (CAD) undergoing open-heart surgery with cardiopulmonary bypass (CPB), in order to better characterize oxidative stress–related and redox-mediated pathophysiological processes associated with the development and progression of coronary heart disease. The gene discussed is SDF4; the disease is coronary artery disorder.