A comparison of high-dose and low-dose tranexamic acid antifibrinolytic protocols for primary coronary artery bypass surgery

BACKGROUND AND AIMS: Tranexamic acid (TA) is used for prophylactic antifibrinolysis in coronary artery bypass surgeries to reduce bleeding. We evaluated the efficacy of two different doses of TA for prophylactic antifibrinolysis in patients undergoing primary coronary artery bypass grafting (CABG) surgery in this retrospective cohort study at a tertiary care referral centre. METHODS: One-hundred eighty-four patients who underwent primary CABG with cardiopulmonary bypass (CPB) via sternotomy between January 2009 and June 2011 were evaluated. Pre-operative patient characteristics, intraoperative data, post-operative bleeding, transfusions, organ dysfunction and 30-day mortality were compared between high-dose TA (30 mg/kg loading dose followed by infusion of 15 mg/kg/h until the end of surgery along with 2 mg/kg priming dose in the bypass circuit) and low-dose TA (15 mg/kg loading dose followed by infusion of 6 mg/kg/h until the end of surgery along with 1 mg/kg priming dose in the bypass circuit) groups. Univariate comparative analysis of all categorical and continuous variables was performed between the two groups by appropriate statistical tests. Linear and logistic regression analyses were performed to control for the effect of confounding on the outcome variables. RESULTS: Chest tube output, perioperative transfusion of blood products and incidence of re-exploration for bleeding did not differ significantly (P> 0.05) between groups. Post-operative complications and 30-day mortality were comparable between the groups. The presence of cardiogenic shock and increased pre-operative creatinine were found to be associated with increased chest tube output on the post-operative day 2 by multivariable linear regression model. CONCLUSIONS: Low-dose TA protocol is as effective as high-dose protocol for antifibrinolysis in patients undergoing primary CABG with CPB.