Cytokine responses and myocardial injury in coronary artery bypass grafting

OBJECTIVE: Cardiopulmonary bypass is acknowledged to be one of the major causes of a complex systemic inflammatory response after cardiac surgery, and it may contribute to postoperative complications and even multiple organ dysfunction. We here compared the cytokine responses and the degree of myocardial injury after coronary artery bypass grafting with or without cardiopulmonary 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 myocardium. Levels of the MB isoenzyme of creatine kinase (CK-MB) were also measured after the operation. RESULTS: Levels of TNF-alpha were low in both groups. 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 patients after reperfusion (p=0.006 and 0.001 respectively). Postoperative CK-MB 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 results indicated that off-pump revascularization was associated with reduced cytokine responses and less severe myocardial injury. The degree of myocardial injury, as defined by CK-MB release, correlated with cytokine release. Intervention designed to reduce cytokine responses in cardiac surgery may be advantageous for patients with severe comorbidity.