Fibrinolysis-adjusted perioperative low-dose aprotinin reduces blood loss in bypass operations

Background. Postoperative bleeding still remains a serious problem in bypass surgery. This study evaluated fibrinolysis and perioperative low-dose antifibrinolytic regimens adjusted to the time course of fibrinolysis. Methods. In a prospective, randomized study of 42 patients undergoing bypass grafting, patients received low-dose aprotinin (group A; n 5 14) or low-dose tranexamic acid (group TA; n 5 14) intraoperatively and postoperatively, respectively, with no antifibrinolytics for comparison (group C; n 5 14). Parameters of procoagulation, fibrinolysis, and activated factor VII were measured preoperatively, intraoperatively, and postoperatively. Blood loss was determined up to 24 hours. Results. The level of thrombin‐antithrombin III complex was significantly decreased postoperatively in the treatment groups (group A and TA versus C: 25 6 14 and 19 6 10 mg/L, respectively, versus 40 6 21 mg/L; p < 0.05). Levels of plasmin‐antiplasmin complexes were significantly decreased postoperatively in group A (607 6 231 mg/L) versus group C (825 6 225 mg/L) (p < 0.05) but were increased in group TA (1,145 6 394 mg/L) versus group C (p < 0.05). At all times intraoperatively and postoperatively, levels of D-dimers were significantly decreased in group A and group TA versus control (p < 0.001), indicating that fibrinolysis persists after the operation. Intraoperatively, the factor VIIa level decreased significantly in group A (20 6 8 mU/mL) versus group C (31 6 15 mU/mL) (p < 0.05), but not in group TA (32 6 15 mU/mL). Blood loss was significantly lower in group A (135 6 37 mL) and group TA (155 6 71 mL) versus group C (354 6 170 mL) (p < 0.001). Conclusions. This low-dose aprotinin regimen adjusted to perioperative fibrinolysis reduces blood loss significantly in coronary bypass grafting. For further progress in this subject, clinical investigations of individual fibrinolysis-adjusted antifibrinolytic treatment seems warranted.