RESUMO
Repeated cardiac operations are increasing in number and represent a group particularly at risk for bleeding. Bleeding during cardiac surgery is due in part to the activation of the fibrinolytic system and the systemic inflammatory response. Although tranexamic acid [TA] is used to reduce bleeding after cardiac surgery, there is large variation in the recommended dose. The dose of prophylactic tranexamic acid administered in CABG using CPB and in particular in redo cases has not been adequately studied. This prospective randomized double-blinded study aims to compare the efficacy of two regimens of prophylactic TA administration to reduce bleeding and blood transfusion in redo CABG. 120 adult patients undergoing redo coronary revascularization using CPB were randomly divided into two equal groups. Patients in group A received a loading dose infusion of TA 10 mg.kg[-1] over 20 minutes before sternotomy, followed by 1 mg.kg[-1] hr[-1] infusion over the following 6 hours. While patients in group B received a loading dose of TA of 25 mg.kg[-1] infused intravenously over 20 minutes before sternotomy, followed by placebo infusion over the following 6 hours. The anesthetic and surgical techniques and the anticoagulation protocol were standardized for all patients. There was no statistically significant difference between the two groups regarding the demographics, preoperative and operative characteristics. The postoperative platelet counts and prothrombin times show no statistically significant change between both groups, while the postoperative PIT [51.7 +/- 1.94 seconds versus 50.9 +/- 1.99 seconds] and hematocrit [23.2 +/- 0.95% versus 22.8 +/- 0.92%] show statistically significant higher level in Group A [p value <0.001]. The blood loss shows highly significant decrease in group A [1114.9 +/- 50.22 versus 1350.74 +/- 22.5 ml] [p value <0.001]. The use of red blood cell transfusion shows highly significant statistical decrease in group A [p value <0.001]. While the platelet and fresh frozen plasma transfusion show statistically significant decrease in group A [p value <0.05]. The percentage of patients not receiving any blood product transfusion during or after operation shows statistically significant decrease in group A [p value <0.05]. The data regarding risk of complications potentially caused by hypercoagulability shows no statistically significant change between both groups. Administration of tranexamic acid loading dose infusion of 10 mg.kg[-1] over 20 minutes before sternotomy, followed by 1 mg.kg[-1] hr[-1] infusion over the following 6 hours, offers a better antifibrinolytic effect than a loading dose of 25 mg.kg[-1] infused intravenously over 20 minutes before sternotomy, reducing blood loss and requirement for transfusion in patients undergoing redo coronary revascularization without increasing the risk of hypercoagulability