The Changes and Effects of the Plasma Levels of Tumor Necrosis Factor after Coronary Artery Bypass Surgery with Cardiopulmonary Bypass

Abstract

Systemic inflammatory response after cardiopulmonary bypass (CPB) is thought to result from contact of cellular and humoral blood components with the synthetic material of the extracorporeal circulation system, leukocyte and endothelial activation caused by ischemia and reperfusion or endotoxins, or by surgical trauma. Proinflammatory cytokines, such as tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, and IL-8, play an important role in the inflammatory processes after CPB and may induce cardiac and lung dysfunction. This study examined the association of the increased release of TNF-alpha with increased myocardial and lung injury after CPB and its effect on postoperative morbidity. Twenty patients undergoing elective coronary artery bypass grafting (CABG) were included in the study. Four intervals of blood samples were obtaind and assayed for TNF-alpha, white blood cells, C-reactive protein, and erythrocyte sedimentation rate. All patients were similar with regards to preoperative and intraoperative characteristics, and clinical outcomes were comparable. Plasma levels of TNF-alpha rose more than 20 pg/mL during and after standard CPB in 13 patients (group 1), whereas the plasma levels were less than 20 pg/mL in the remaining 7 patients (group 2) after CPB. The patients of the first group had increased mediastinal bleeding and prolonged intubation time compared to the other group. Cardiac surgery and CPB stimulate systemic inflammatory processes characterized clinically by changes in cardiovascular and pulmonary function. Significant morbidity is rare, but most patients undergoing CPB exhibit some degree of organ dysfunction due to activation of the inflammatory response. This study showed that there were no major clinical results of TNF-alpha and white blood cell level, C-reactive protein, and erythrocyte sedimentation rate after the operation, but in patients with a high level of TNF-alpha (more than 20 pg/mL), increased mediastinal bleeding and longer orotracheal intubation time was observed. A number of studies have shown the increase of TNF-alpha after open heart surgery; however, the specific level of TNF-alpha was first described as 20 pg/mL in this study.