The Influence of Aprotinin and Tranexamic Acid on Platelet Function and Postoperative Blood Loss in Cardiac Surgery

Background: Antifibrinolytic drugs including aprotinin and tranexamic acid are currently used in cardiac surgery to reduce postoperative bleeding and transfusion requirements, and may have different effects on platelets. We therefore evaluated platelet function after cardiopulmonary bypass (CPB) and cardiac surgery to determine the effect of either aprotinin or tranexamic acid.

Methods: In a prospective, randomized study, 50 patients scheduled for elective cardiac surgery with CPB were evaluated. Patients received high-dose aprotinin (n = 25) or tranexamic acid (n = 25) as antifibrinolytic drugs. Coagulation and platelet function were assessed preoperatively, after CPB, 3 and 24 h after surgery using modified thrombelastography and whole blood aggregometry.

Results: Impaired coagulation after CPB occurred in both groups compared with preoperative data (P < 0.01). In contrast to modified thrombelastography, thrombin receptor-mediated aggregometry after CPB was significantly decreased only in those patients receiving tranexamic acid until the end of the study period in comparison to the aprotinin group (P < 0.05). Aprotinin-treated patients showed significantly less chest tube drainage (575 mL +/- 228 vs 1033 mL +/- 647, P < 0.05) and need for postoperative transfusion requirements (P < 0.01) compared with the tranexamic acid group.

Conclusions: Platelet function measured by whole blood aggregometry is better preserved by aprotinin than tranexamic acid and may be responsible for producing less bleeding within the first 24 h after CPB.