Use of heparin-coated cardiopulmonary bypass circuit with low-dose heparin reduces postoperative bleeding.

Postoperative bleeding was examined in patients undergoing cardiopulmonary bypass with a heparin-coated circuit and low-dose heparin. Out of 150 patients who underwent cardiopulmonary bypass for longer than 90 minutes, 74 received a standard dose (300 IU/kg) of heparin with an uncoated circuit (group C) and 76 received a low-dose (150 IU/kg) of heparin with a heparin-coated circuit (group H). The coagulation and fibrinolytic systems were investigated in 24 patients. Re-opening of the chest due to bleeding was performed in 5 patients in group C (7%), but none of the patients in group H (p=0. 03). The median of blood loss in the first 12 hours after surgery was 292 ml in group C, and 216 ml in group H (p=0.006). There were no significant differences in the peak thrombin-antithrombin complex concentration between the two groups. The plasmin-alpha 2 plasmin inhibitor complex concentrations after protamine administration were 1.9 ng/ml (median) in group C and 1.1 ng/ml in group H (p=0.002). The use of heparin-coated cardiopulmonary bypass circuits with low-dose heparin suppressed the activation of fibrinolysis. This may explain the reduction in postoperative bleeding.