Altered concentrations of terminal complement complexes, anaphylatoxins, and leukotrienes in the coronary sinus during cardiopulmonary bypass.

The aim of this study was to determine if the hypoperfused heart activates complement with formation of anaphylatoxins, terminal complement complexes (TCC), or leukotrienes during cardiopulmonary bypass. Fifteen patients undergoing elective cardiopulmonary bypass surgery were studied regarding complement and leukotriene activation. Blood samples were drawn serially from the radial artery and coronary sinus. The plasma concentrations of the complement components C1INH, C3, C4, and C5 decreased during the procedure, whereas C3a and TCC increased. Protamine reversal of heparin further increased the plasma levels of C3a and TCC. No significant changes in plasma levels of C5a and leukotriene C4 were observed during cardiopulmonary bypass. The activity of the anaphylatoxin inactivator (AI) decreased in both the radial artery and the coronary sinus. There were no significant differences between the concentrations of complement components and leukotriene C4 in blood from the radial artery and coronary sinus. The levels of C3a and TCC increased and C1INH, C3, C4, C5, and the anaphylatoxin inactivator activity decreased to the same extent in the coronary sinus and the radial artery. Thus, the heart does not appear to be the primary site for the altered concentrations of these endogenous vasoactive substances.