The effect of two different doses of aprotinin on hemostasis in cardiopulmonary bypass surgery: similar transfusion requirements and blood loss

Background and Objectives. Various dosages of aprotinin have proven to be e ffective in reducing blood loss and allogeneic transfusion requirements in cardiopulmonary bypass surgery, despite the controversy surrounding the pre cise hemostatic mechanisms of this drug. The aim of our prospective, random ized, double-blind study was to assess differences in blood loss and transf usion requirements and the effect of two dosages of aprotinin on hemostatic activation. Design and Methods. Patients undergoing coronary artery bypass grafting rec eived high-dose aprotinin (n=28), pump-prime-only (PPO) aprotinin (n=28), o r placebo (n=28). Results. The high-dose and the PPO groups had a significantly lower blood l oss (985 mL [95%CI 845-1,102] and 1,255 mt, [95% CI 1,025-1,406], respectiv ely) than the placebo group (1,416 mt, 95%CI 1,248-1,612]. Transfusion requ irements were lower in the aprotinin-treated groups than In the patients re ceiving placebo (21 units and 15 units in the high and low-dose groups vs 5 9 units in placebo group). As far as concerns parameters of thrombin genera tion, the aprotinin groups showed a significant reduction of F1+2 prothromb in fragment but not of thrombin-antithrombin complexes. There were higher l evels of natural anticoagulants, i.e. antithrombin, protein C and protein S , in the high-dose aprotinin group. As regards fibrinolysis parameters, D-d imer was lower in the aprotinin groups, and the levels of alpha2-antiplasmi n and plasmin-alpha2-antiplasmin complexes were raised. in summary, both do sages of aprotinin were equally effective in reducing blood loss and transf usion requirements. There was a Tower activation of coagulation and fibrino lysis in cardiopulmonary bypass patients treated with aprotinin: the levels of natural anticoagulants were less decreased in the high-dose group. No d ifferences in thrombotic complications were observed between aprotinin grou ps. Interpretation and Conclusions. Our study Shows that both dosages of ap rotinin are safe and effective in reducing transfusion requirements. Consid ering the difference in cost of using a low-dose or high-dose schedule. the former should be recommended for patients undergoing cardiopulmonary bypas s surgery. (C) 2000. Ferrata Storti Foundation.