Does tranexamic acid save blood in minimally invasive total knee arthroplasty?
Clin Orthop Relat Res 2011;469(7):1995-2002.
In their non-blinded, non-randomized, prospective study, Lin and co-workers compared the effect of a prophylactic intraoperative single-dose application of 10 mg/kg tranexamic acid (TA) on blood loss, transfusion rate and the incidence of thromboembolic events in 50 patients undergoing minimally invasive total knee arthroplasty (unilateral, cemented) under general anesthesia. Another 50 patients served as a control and received an equivalent volume of saline. Every arthroplasty was performed or supervised by the same surgeon. The transfusion trigger for red blood cells was set at a hemoglobin concentration between 8.5 and 9 g/dL. Thromboprophylaxis was performed with 20 mg enoxaparin s.c. every 12 hours until discharge. Total blood loss (833 vs. 1453 mL) and transfusion rate (4 vs. 20%) were significantly lower in the TA group. One patient per group had radiographically confirmed deep vein thrombosis (DVT) in the operated leg, no patient had clinical evidence of pulmonary embolism.
Although rather small, this study clearly demonstrates the efficacy of a prophylactic single-dose application of tranexamic acid in reducing red blood cell transfusion in knee arthroplasty. At the same time the treatment was safe with regard to the risk of DVT. These results is consistent with other reports of efficacy and safety of TA in different trauma and blood loss scenarios. Systemic and, probably even more, local hyperfibrinolysis seem to play a central and long underestimated role in the pathophysiology of perioperative blood losses. Early and sometimes even prophylactic application of TA seems to be a simple, cheap, effective and safe measure to reduce transfusion in high blood loss surgery.
– Oliver Habler