COMPLEMENT AND GRANULOCYTE ACTIVATION IN 2 DIFFERENT TYPES OF HEPARINIZED EXTRACORPOREAL CIRCUITS

Complement and granulocyte activation were studied in cardiopulmonary bypass circuits completely coated with either end-attached covalent-bo nded heparin, the Carmeda BioActive Surface, or with the Duraflo II bo nded heparin, in combination with reduced systemic heparinization (act ivated clotting time > 250 seconds), The control groups were perfused with uncoated circuits and full heparin dose (activated clotting time > 480 seconds), Altogether 67 patients undergoing elective first-time myocardial revascularization were investigated, having extracorporeal perfusion dth a Duraflo II coated circuit (n = 17), an identical but u ncoated circuit (n = 17), a Carmeda coated circuit (n = 17), or an equ ivalent uncoated circuit (n = 16), During cardiopulmonary bypass, the C3 activation products C3b, iC3b, and C3c (CSbc) and the terminal SC5b -9 complement complex increased markedly in all four groups compared w ith baseline, but significantly less in the two coated groups than in their control groups, Additionally, a significantly lower concentratio n of C3bc was observed in the Carmeda coated group, with maximal incre ase of median 28 AU/ml compared with 50 AU/ml in the Duraflo II coated group (p = 0.003), Similarly, in the Carmeda coated group, the maxima l increase of terminal complement complex was considerably lower (0.8 AU/ml) than the levels recognized in the Duraflo n, coated group (2.4 AU/ml) (p < 0.001), The release of the granulocyte activation enzymes myeloperoxidase and lactoferrin increased from the beginning of the op eration, with peak levels at the end of bypass, A significant reductio n of lactoferrin release was recognized when comparing the coated grou ps with the control groups, The difference between the two coated grou ps (Carmeda 229 mu g/L; Duraflo II 332 mu g/L; p = 0.05) was marginall y significant, For myeloperoxidase, no significant differences were ob served between the coated and uncoated groups, In conclusion, both typ es of heparin-coated circuits reduced complement activation and releas e of lactoferrin, but the Carmeda circuit proved to be more effective than the Duraflo II equipment.