COMPLETE HEPARIN-COATED CARDIOPULMONARY BYPASS AND LOW HEPARIN DOSE REDUCE COMPLEMENT AND GRANULOCYTE ACTIVATION

Complete heparin-coated extracorporeal circuits, including cardiotomy reservoir, have recently become available for routine cardiac surgery. The effects on complement and granulocyte activation using a heparin- coated circuit in combination with reduced systemic heparinization (ac tivated clotting time (ACT) > 250 s) were studied in 33 patients under going elective first time myocardial revascularization. The patients w ere prospectively randomized either to a heparin-coated group (Group H , n = 17), or to a control group (Group C, n = 16)treated with an iden tical uncoated circuit and full heparin dose (ACT > 480 s). During car diopulmonary bypass (CPB) the C3 activation products C3b, iC3b, and C3 c (C3bc) and the terminal SC5b-9 complement complex (TCC) increased ma rkedly in both groups compared to baseline, but to a much lesser exten t in the heparin-coated group. The maximal increase of C3bc during the operation was a median of 28 arbitrary units (AU)/ml in the heparin-c oated group, compared to 45 AU/ml in the nr control group (P = 0.01). Similarly, in Group H the maximal increase of TCC was significantly lo wer (median 0.8 AU/ml) than the levels recognized in Group C(median 1. 9 AU/ml) (P < 0.0001). The release of the granulocyte activation enzym es lactoferrin and myeloperoxidase also increased during CPB in both g roups compared to baseline level. The maximal increase of lactoferrin concentration was a median of 229 mu g/l in Group H and significantly lower than 647 mu g/l in the control group (P = 0.0002). As for myelop eroxidase, there were no significant intergroup differences. In conclu sion, a complete heparin-coated circuit and low systemic heparinizatio n for CPB in coronary artery surgery were associated with reduced acti vation of the complement system and less release of lactoferrin. The r esults indicate improved biocompatibility of this option for extracorp oreal circulation.