American journal of hematology
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Randomized Controlled Trial Clinical Trial
Effect of tranexamic acid on platelet ADP during extracorporeal circulation.
Seventeen adults received the antifibrinolytic drug tranexamic acid during cardiac surgery utilizing extracorporeal circulation (ECC). In 8 patients, drug administration began prior to skin incision (pre-ECC); infusions commenced after ECC and protamine administration in another 9 patients (post-ECC). Compared with the post-ECC group, the pre-ECC group exhibited less bleeding via mediastinal drains (420 vs. 655 mL/12 h median, P = 0.024), decreased frequency of the presence (greater than or equal to 10 micrograms/mL) of fibrin split products (P less than 0.05), and greater platelet dense granule content of adenosine diphosphate after surgery (15.47 vs. 4.05 nmoles/mg protein median, P = 0.021). ⋯ Plasmin inactivated with tranexamic acid retained its ability to inhibit thrombin-induced platelet activation, thus suggesting that tranexamic acid inhibits plasmin's catalytic activity and not its binding to platelets. Both clot lysis and platelet dysfunction may contribute to bleeding after ECC. Tranexamic acid blocks plasmin-induced partial platelet activation during ECC, thus preserving platelet function and promoting hemostasis after ECC.