[The evaluation of the bio-compatibility and the clinical usefulness of heparin-coated cardiopulmonary bypass circuits].

We studied the biocompatibility and the clinical usefulness of heparin-coated cardiopulmonary bypass circuits (Duraflow-II) compared with non-coated circuits. First study was done to clarify the biocompatibility of heparin coated circuit. 33 cases of elective coronary artery bypass grafting were randomized into two grops. Both group had full dose heparin in this study and laboratory tests were done such as blood cell count, free hemoglobin, AT-III, fibrinogen, FDP, and complement system. The use of heparin-coated circuits resulted in a reduction of C3a generation, and a reduction of fibrinogen consumption. The decline of AT-III may be due to bonding of coated heparin to AT-III, leading to effective anticoagulation. Next study was carried out in 26 cases. In heparin coated group, the amount of heparin was reduced to 200 IU/kg compared to 350 IU/kg in control group. ACT was maintained above 300 sec. and 400 sec. respectively. The amount of post operative bleeding was identical in both groups. There was no case which required autologous blood transfusion, re-operation for bleeding in both groups. Myocardial infarction and hospital mortality were not seen in this study. Concerning the fear of graft occlusion in low dose heparin surgery, there was no statistical difference of graft patency in both groups. In conclusion, heparin coated CPB circuits (Duraflo-II) are favorable in the meaning of biocompatibility and sefely used with low dose heparin.