HEPARIN-COATED CIRCUIT DURING CARDIOPULMONARY BYPASS - A CLINICAL-STUDY USING CLOSED-CIRCUIT, CENTRIFUGAL PUMP AND REDUCED HEPARINIZATION

A prospective randomized study was performed to investigate the effect of surface coating with covalently endpoint-attached heparin (Carmeda Bio Active Surface) and reduced general heparinization on haematologi cal indices and complement C5 activation. Care was taken to optimize t he theological design of the system using centrifugal pump and a close d system without venting or machine suction. Twenty patients scheduled For aortocoronary bypass grafting (EF > 0.5) participated in the stud y. Ten patients were randomized to be treated with heparin-coated equi pment (CBAS) and reduced i.v. heparin (1.5 mg.kg(-1)) while 10 patient s treated with identical but noncoated equipment and full heparinizati on (3 mg.kg(-1)) served in a Control group. A vacuum suction was used to collect the blood from the operating Geid and it was autotransfused at weaning from extracorporeal circulation (ECC). Blood samples were obtained from the venous (precircuit) and arterial (postcircuit) side. We used a new and very specific method for detection of C5a based on monoclonal antibodies. The concentration of C5a was low in both groups during the operation but a significant increase was seen on days 1 an d 2. In the Control group there was an increase from 10.2 ng.mi(-1) +/ - 1.2 to 27.5 ng.ml-1 +/- 4.8 on day 2 and in the CBAS group from 10.7 ng.ml(-1) +/- 1.2 to 35.6 ng.ml(-1) +/- 11.6 on day 2 (NS between gro ups). The granulocytes and total leukocyte count increased at the end of ECC and was maintained at the elevated level throughout the study p eriod. The amount of free haemoglobin was high in the autotransfused b lood in both groups. The present results confirm the feasibility of re ducing general heparin when using heparin-coated systems but the study does not support the superiority of such coating with regard to bioco mpatibility in short procedures with a theologically optimized circuit . The potential benefit from reduced heparin and protamine has not bee n fully evaluated.