The authors have conducted a randomized controlled trial on the efficacy and safety of tranexamic acid in 100 patients undergoing total knee replacement surgery. They show that administration of tranexamic acid results in a reduction of about 500 ml in drained blood during the operation and less hemoglobin decrease 12 hours postoperatively compared to placebo. The mean number of transfused red blood cell units was 0.7 in the tranexamic acid group compared to 1.9 in the control group and the proportion of patients needing any transfusion decreased from 90% in placebo-treated patients to 56% in tranexamic acid-treated patients (both statistically significant).
This is an interesting study and the results fit well with other trials showing the prohemostatic effect of tranexamic acid in perioperative settings. However, a few critical comments may be made. Blood loss and transfusion requirements are quite high in this study, and many surgeons and centers will not recognize a 90% transfusion rate in patients undergoing knee replacement. Also, it would be important to show a beneficial effect on clinically relevant outcomes apart from blood loss and transfusion. Lastly, and importantly, the dosing schedule of tranexamic acid is puzzling as the continuance of the drug up to 5 days postoperatively does not seem warranted as it may add to the very high risk of thromboembolic complications in these patients (who were also not given heparin prophylaxis). The fact that the authors did not encounter clinically apparent thrombosis is not very convincing as venography studies show non-symptomatic thrombosis rates up to 30% after knee replacement studies.
– Marcel Levi