Heparin-coated cardiopulmonary bypass equipment. I. Biocompatibility markers and development of complications in a high-risk population

Objectives: 1, To study possible clinical benefits of heparin-coated cardio pulmonary bypass in patients with a broad range of preoperative risk factor s. 2, To evaluate the correlation between the terminal complement complex a nd clinical outcome. 3, To identify clinical predictors of complement activ ation and correlates of granulocyte activation during cardiac surgery. Meth ods: Blood samples from adults undergoing elective cardiac surgery with Dur aflo II heparin-coated (n = 81) or uncoated (n = 75) cardiopulmonary bypass sets (Duraflo coating surface; Baxter International, Inc, Deerfield, Ill) were analyzed for activation of complement (C3 activation products, termina l complement complex), granulocytes (myeloperoxidase, lactoferrin), and pla telets (beta-thromboglobulin) by enzyme immunoassays, Preoperative risk was assessed by means of the "Higgins' score." Complications (cardiac, renal, pulmonary, gastrointestinal, and central nervous system dysfunction, infect ions, death) were registered prospectively, Data were analyzed by analysis of variance, logistic regression, and linear regression. Results and conclu sions: Sixty-seven percent of the patients had predefined risk factors. Com plications developed in 53 patients (34%), equivalently with and without he parin-coated bypass sets (P = .44-.82), despite a significant reduction in complement and granulocyte activation by heparin coating. No clear-cut rela tionship between the terminal complement complex and outcome was found, eve n if it was significant in the models for renal and central nervous system dysfunction and infections (P = .006). The Higgins' score was significantly related to complement activation (P < .05). Approximately 50% of the varia tion in granulocyte activation was explained by complement (P less than or equal to .01) and platelet activation (P < .05), heparin/protamine dose rat io (P = .02), duration of cardiopulmonary bypass (P < .01), and gender (P < .05). Therefore measures reducing complement activation alone will not nec essarily reduce granulocyte activation sufficiently for clinical significan ce.