Reduced complement and granulocyte activation with heparin-coated cardiopulmonary bypass

Plasma concentrations of the complement activation products C3b, iC3b, and C3c; the terminal C5b-9 complement complex; and the granulocyte proteins calprotectin, myeloperoxidase, and lactoferrin were assessed in two groups of patients undergoing aortocoronary bypass procedures. In 10 patients operated on, the bypass circuits were coated by the Carmeda Bio-Active Surface and systemic heparinization was reduced to 1.5 mg/kg; in another 10, the systems were uncoated and the dosage of systemic heparinization was 4 mg/kg. In both groups, significant complement activation was observed after the onset of cardiopulmonary bypass, but the maximum levels of C3b, iC3b, and C3c and the terminal C5b-9 complement complex were significantly lower in the heparin-coated group. In both groups, a significant increase in calprotectin, myeloperoxidase, and lactoferrin release was observed by the end of operation. The maximum myeloperoxidase levels were significantly lower in the heparin-coated group than those in the uncoated group (p = 0.03). There was a correlation of borderline significance between the formation of terminal C5b-9 complement complex and lactoferrin release, as well as between the formation of terminal C5b-9 complement complex and myeloperoxidase release (p = 0.05). The postoperative blood loss did not differ significantly between the two groups. We conclude that coating by end point-attached and functionally active heparin allows a significant reduction in the amount of systemic heparinization, and significantly reduces complement and granulocyte activation.