Cytokine Responses to Cardiopulmonary Bypass: Lessons Learned From Cardiac Transplantation

Background. A growing body of evidence relates the release during cardiopulmonary bypass (CPB) of proinflammatory cytokines, such as tumor necrosis factor-α, interleukin (IL)-6, and IL-8, to the postoperative systemic inflammatory response syndrome. Antiinflammatory cytokines, such as IL-10, however, may also play an important role in limiting these complications. Methods. The English-language literature was reviewed. Emphasis was placed on cytokine responses during clinical CPB for cardiac operations and, in particular, for heart and heart-lung transplantation. Results. The recent data indicate that (1) although cytokine release can be triggered by many factors during CPB, ischemia-reperfusion may play the most important role; (2) the levels of tumor necrosis factor-α, IL-6, and IL-8 are correlated with the duration of cardiac ischemia and the myocardium is a major source of these three cytokines during CPB; (3) IL-10 levels are correlated with the duration of CPB and the liver is a major source of IL-10 during CPB; and (4) steroid pretreatment is an effective intervention to inhibit the release of proinflammatory cytokines and enhance IL-10 production. Conclusions. The improved knowledge of cytokine responses to CPB may help to develop interventions aimed at reducing postoperative morbidity and mortality. (Ann Thorac Surg 1997;63:269–76)