Antifibrinolytics

Antifibrinolytics have been increasingly used during operations associated with high risk of bleeding. New research and understanding of coagulation and access to point of care coagulation monitors allow a goal-directed perioperative coagulation management strategy. Certain drugs, such as aprotinin (1) and hydroxyethyl starch solutions, have been temporarily suspended from the market (2, 3) because of safety concerns. Recent transfusion guidelines recommend (Class 1A) antifibrinolyt-ics for routine administration in cardiac procedures if there are no contraindications (4). Fibrinolysis is a physiological process where the activated plasmino-gen removes excess fibrin and promotes better fibrin clot formation and wound healing. Tissue plasminogen activator (t-PA) and other activators of plasminogen are first line agents in lysis therapy. Inhib-itors of this process act at the step where plasminogen is converted to plasmin, by reversely blocking the lysine binding sites of plasmin or by active inhibition of plasmin via serine protease inhibition. The drugs used for inhibition of fibrinolysis are the lysine analogues, tranexamic acid and ε-aminocaproic acid, and the serine protease inhibitor, aprotinin. Aprotinin also inhibits kallikrein and trypsin, and decreases the activation of neutrophils and platelets (5). Inhibition of fibrinolysis reduces bleeding and blood transfusions in many types of surgery. Cardiopulmonary bypass (CPB) and cardio-vascular surgery activate inflammatory pathways, coagulation cascades , and fibrinolysis. Additionally, hemodilution and hypothermia during CPB also have detrimental effects on coagulation. However, one-third of off-pump coronary bypass patients receive blood products and this percentage might be reduced by the usage of antifi