Biocompatibility of heparin-coated circuits used in cardiopulmonary bypass.

The combined effect of heparin coating of cardiopulmonary bypass (CPB) circuits and reduced dose of systemic heparin on activation of the complement system and blood leukocytes was investigated in 19 patients undergoing coronary bypass surgery and randomly allocated to two groups. A heparin-coated CPB circuit together with a 50% reduction of the standard heparin dose were used for ten patients (HC group), and a standard CPB circuit with a standard heparin dose (300 IU/kg) for nine (C group). Significant rise in the levels of neutrophil-derived myeloperoxidase, lactoferrin and calprotectin were observed during CPB in both groups, but the total accumulated levels were significantly lower in the HC than in the C group (p < 0.05). Complement activation, assessed from levels of C3a and terminal complement complexes was similar in both groups. The lower levels of myeloperoxidase, lactoferrin and calprotectin during CPB in the HC group indicate that surface modification with end-point attached heparin enhances the biocompatibility of CPB.