HEMOSTASIS AT LOW HEPARIN DOSAGE DURING CARDIOPULMONARY BYPASS WITH HEPARIN-COATED CIRCUITS IN PIGS

Cardiopulmonary bypass (CPB) causes activation of cascade systems. Alt hough heparin coating of CPB circuits improves biocompatibility, the e ffects on coagulation remain controversial. Theoretically, heparin coa ting should permit the reduction of systemic anticoagulation during CP B. We investigated influences on haemostatic variables in animal CPB, comparing heparin-coated circuits and reduced systemic heparinization (group HC) with uncoated circuits and full heparinization (group C). T wenty pigs underwent 2-h CPB. Seven (HC, n = 4; C, n = 3) were weaned from CPB and studied for up to 4 h. Total administered heparin was 470 +/- 6 IU/kg (mean +/- SEM) in group C and 100 +/- 0 IU/kg in group HC . Protamine dosage was significantly reduced in group HC. In group C, levels of prothrombin complex, factor Vm and adhesive platelets were r educed significantly during CPB, and postoperatively there were signif icantly lower values of prothrombin complex, fibrinogen, antithrombin Ill, factor VIII and adhesive platelets but a significantly increased concentration of von Willebrand factor and cumulative bleeding after 4 h. In conclusion, heparin-coated CPB circuits combined with lowered h eparin dosage reduced coagulation factor consumption and preserved pla telet function, possibly contributing to improved postoperative haemos tasis.