Background: Perioperative administration of tranexamic acid (TA), decreases bleeding and the need for transfusion after cardiac procedures. Hence, the results may vary in different clinical settings and the most appropriate timing to get the best results is unclear. The primary objectives of the present study were to determine the efficacy of TA in decreasing chest tube drainage, the need for perioperative allogeneic transfusions and the best timing for TA administration following primary, elective, coronary artery bypass grafting (CABG) in patients with a low baseline risk of postoperative bleeding.

Methods: In this double-blind, prospective, placebo-controlled clinical trial in Seiedoshohada Hospital during 2011-2012, we evaluated 150 patients scheduled for elective, primary coronary revascularization. They were randomly divided into three groups. Group B received tranexamic 10 mg/kg prior to, Group A received tranexamic acid 10 mg/kg after cardiopulmonary bypass and group C received an equivalent volume of saline solution. Blood requirement and postoperative chest tube drainage were recorded.

Results: The placebo group (group C) had a greater postoperative blood loss 12 h after surgery (501±288 vs. 395±184 in group B and 353±181 mL in group A, P=0.004). The placebo group also had greater postoperative total blood loss (800±347 vs. 614±276 in group B and 577±228 mL in group A, P=0.001). There was a significant increase in allogeneic blood requirement in the placebo group (P=0.001).

Conclusion: For elective, first time coronary artery bypass surgery, a single dose of tranexamic acid before or after cardiopulmonary bypass is equally effective.