LAUSR

STUDY OBJECTIVE Activated clotting time (ACT) is a non-specific test to evaluate the adequacy of systemic heparinization whose value could be influenced by many factors. Tranexamic acid (TXA) is a widely used antifibrinolytic agent worldwide and whether TXA influences ACT value in cardiac surgical patients remains unknown. Current study was performed to address this question. DESIGN Systematic review and meta-analysis. PUBMED, Cochrane Library, EMBASE, OVID and Chinese BioMedical Literature & Retrieval System were searched using search terms "tranexamic acid", "activated clotting time", "cardiac surgery", "randomized controlled trial" till May 7th, 2020, to identify all relevant randomized controlled trials (RCTs). SETTING Operating room. PATIENTS Cardiac surgical patients. INTERVENTIONS TXA or placebo. MEASUREMENTS Primary outcomes of interest included peri-operative ACT values. Secondary outcomes of interest include heparin dosage, protamine dosage, postoperative bleeding and blood transfusion. MAIN RESULTS Search yielded 13 studies including 1168 patients, and 619 patients were allocated into Group TXA and 549 into Group Control (placebo). Meta-analysis suggested that, ACT values after heparinization [(WMD = -1.45; 95%CI: -12.52 to 15.43; P = 0.84)] and after protamine [(WMD = -1.18; 95%CI: -2.81 to 0.46; P = 0.16)] were comparable between Group TXA and Group Control, and that TXA did not influence heparin dose in adult patients [(WMD = 0.38; 95%CI: 0.30 to 0.46; P<0.00001) with no heterogeneity (I2 = 4%, P = 0.35)] and protamine dose for heparin reversal [(WMD = 5.23; 95%CI: -0.33 to 10.80; P = 0.07) with no heterogeneity (I2 = 0, P = 0.58)]. Meta-analysis also demonstrated that, TXA administration significantly reduced post-operative bleeding volume [(WMD = -126.33; 95%CI: -177.46 to -75.19; P < 0.0001), post-operative red blood cell (RBC) transfusion volume [(WMD = -71.86; 95% CI: -88.22 to -55.50; P < 0.00001), fresh frozen plasma (FFP) transfusion volume [(WMD = -13.83; 95% CI: -23.67 to -4.00; P = 0.006) and platelet concentrate (PC) transfusion volume [(WMD = -0.20; 95% CI: -0.29 to -0.10; P < 0.0001). CONCLUSION This meta-analysis suggested that, TXA administration did not influence ACT value, heparin and protamine doses, but significantly reduced post-operative blood loss and transfusion requirement in cardiac surgical patients.