Cytokine responses and myocardial injury in coronary artery bypass grafting

Objective. Cardiopulmonary bypass is acknowledged to be one of the major ca uses of a complex systemic inflammatory response after cardiac surgery, and it may contribute to postoperative complications and even multiple organ d ysfunction. We here compared the cytokine responses and the degree of myoca rdial injury after coronary artery bypass grafting with or without cardiopu lmonary bypass. Methods: Nine patients underwent off-pump revascularization and 13 with cardiopulmonary bypass. Plasma levels of tumor necrosis factor -alpha (TNF-alpha), interleukin (IL)-6, IL-8 and IL-10 were measured before anesthesia induction, and 5 min. 1, 4, and 20 h after reperfusion to the m yocardium. Levels of the MB isoenzyme of creatine kinase (CK-MB) were also measured after the operation. Results: Levels of TNF-a were low in both gro ups. A delayed elevation of IL-6 was noted in the off-pump group. IL-8 and IL-10 levels were significantly higher in the CPB than in the off-pump pati ents after reperfusion (p=0.006 and 0.001 respectively). Postoperative CK-M B levels were significantly higher in the CPB than in the off-pump group (p =0.001). Cytokine levels correlated with CK-MB values. Conclusion: The resu lts indicated that off-pump revascularization was associated with reduced c ytokine responses and less severe myocardial injury. The degree of myocardi al injury, as defined by CK-MB release, correlated with cytokine release. I ntervention designed to reduce cytokine responses in cardiac surgery may be advantageous for patients with severe comorbidity.