BIOMATERIAL-DEPENDENT BLOOD ACTIVATION DURING SIMULATED EXTRACORPOREAL-CIRCULATION - A STUDY OF HEPARIN-COATED AND UNCOATED CIRCUITS

Objective: Blood activation during extracorporeal circulation is assoc iated with morbidity and mortality in cardiac surgery. This activation can be diminished by usage of heparin-coated circuits. Nitric oxide h as also been reported to influence humoral and cellular components of blood. This study was performed to determine biomaterial-dependent par t of blood activation. Design: Fresh, whole human blood mixed with Rin ger's solution was circulated through a heart-lung machine for two and half hours. Five circuits were heparin-coated (group HC), whilst five other circuits were uncoated (group NC). During the last half hour NO was added to the oxygen/air mixture. Methods: Blood activation was es timated by measuring following parameters: interluekin 6, complement a ctivation products C3a and terminal complement complex, and oxygen fre e radicals (OFR) production capacity, which was determined using chemi luminescence enhanced by serum opsonized zymosan (SOZ) and phorbol myr istate acetate (PMA). Granulocyte activation was measured as release o f myeloperoxidase (MPG) and human neutrophil lipocalin (HNL). Results: OFR in granulocyte suspension stimulated by SOZ and PMA were signific antly lower in the NC group, mostly later during ECC. Similarly, lower neutrophil and monocyte counts were observed in this group. NO increa sed superoxide production in the whole blood in heparin-coated circuit s, but did not change OFR in isolated granulocytes. MPO was also affec ted by heparin-coating. NO supply seemed to increase release of MPO an d HNL. It is concluded that heparin-coating contributed to reduction o f biomaterial-dependent blood activation. An addition of NO at late st age of ECC tended to influence this activation.