ATTENUATION OF CHANGES IN LEUKOCYTE SURFACE-MARKERS AND COMPLEMENT ACTIVATION WITH HEPARIN-COATED CARDIOPULMONARY BYPASS

Background. The inflammatory response induced by cardiopulmonary bypas s can result in severe organ dysfunction in some patients. This postpe rfusion response is caused mainly by contact between blood and the for eign surface of the cardiopulmonary bypass equipment and includes adhe sion of leukocytes to vascular endothelium, which precedes a series of events that mediate inflammatory damage to tissues. Methods. Low-risk patients accepted for coronary artery bypass grafting were randomized to operation with the cardiopulmonary bypass surface either completel y heparin coated (Duraflo II) or uncoated. There were 12 patients in e ach group. Blood plasma sampled during cardiopulmonary bypass was anal yzed for complement activation (C3bc and terminal SC5b-9 complement co mplex) and neutrophil activation (lactoferrin and myelo-peroxidase). I n addition, neutrophils, monocytes, and platelets were counted, and th e expression of surface markers on the neutrophils and monocytes (comp lement receptor [CR] 1, CR3, CR4, and L-selectin) and on the platelets (P-selectin and CD41) was quantified with flow cytometry. Results. Cl inical and surgical results were similar in both groups. In the group with the heparin-coated surface, the formation of the terminal SC5b-9 complement complex was significantly reduced, and the counts of circul ating leukocytes and platelets were significantly less reduced initial ly but were higher at the end of cardiopulmonary bypass compared with baseline. Also, the expression of CR1, CR3, and CR4 was significantly less upregulated and the L-selectin, significantly less downregulated on monocytes and neutrophils. Conclusions. We conclude that heparin co ating reduces complement activation and attenuates the leukocyte integ rin and selectin response that occurs when uncoated circuits are used. (C) 1997 by The Society of Thoracic Surgeons