HEPARIN-COATED CIRCUITS REDUCE THE INFLAMMATORY RESPONSE TO CARDIOPULMONARY BYPASS

Cardiopulmonary bypass generates a systemic inflammatory response incl uding the activation of the complement cascade and leukocytes contribu ting to postoperative morbidity. To evaluate whether the use of hepari n-coated extracorporeal circuits could reduce these activation process es, we performed a study on 30 patients undergoing coronary artery byp ass grafting who were randomly perfused with a heparin-coated circuit (Duraflo II, n = 15) or with a similar noncoated circuit (control, n = 15). Standardized systemic heparinization was applied for every patie nt before cardiopulmonary bypass. The use of heparin-coated circuits r esulted in a reduction of systemic leukocyte activation during cardiop ulmonary bypass reflected by reduced elastase release (p < 0.05) and t umor necrosis factor generation (p < 0.05) manifest after release of t he aortic cross-clamp. In addition, blood samples taken from both the right and left atria after reperfusion revealed that the elastase rele ase from the pulmonary microcirculation was absent in the Duraflo II g roup in contrast to the control group (p < 0.05). The pattern of compl ement activation, likely initiating this inflammatory reaction, was mo dified by heparin coating in two different aspects. There was a signif icant reduction of C3a generation after protamine administration in pa tients perfused with heparin-coated circuits, and there was a decrease of complement hemolytic capacity in pooled human serum incubated with heparin-coated tubing. These observations suggest that heparin coatin g might bind some of the complement components from the classic pathwa y, thereby reducing the inflammatory response to cardiopulmonary bypas s.