Minimizing perioperative blood loss during total knee arthroplasty (TKA) helps curtail the risks and costs of allogeneic blood transfusions. Currently, the most popular pharmacological approach to blood conservation is the antifibrinolytic agent tranexamic acid (TXA). But in a randomized trial published in the October 4, 2017 edition of The Journal of Bone & Joint Surgery, Boese et al. found that a similar and much less expensive compound, epsilon-aminocaproic acid (EACA), performed almost as effectively and just as safely as TXA in patients undergoing unilateral knee replacement.
Although the 98 patients in the study who received TXA averaged less estimated blood loss than the 96 patients who received EACA, no transfusions were required in either group, and there were no statistically significant or clinically relevant between-group differences in the change in hemoglobin levels. On the safety/complication side, there were no statistically significant between-group differences in any measured parameter, including postoperative serum creatinine levels or renal, bleeding, or thrombotic complications. However, there were 3 pulmonary emboli in the EACA group compared with only 1 in the TXA group. While that was not a statistically significant difference, “an observed difference of this magnitude could limit the usefulness of EACA in TKA,” the authors caution.
This study did not compare the current cost of the two compounds, but back in 2012, when the authors’ institution added antifibrinolytics to their blood management program, TXA cost $43/g, compared with $0.20/g for EACA. The cost differential is striking, even when you consider that TXA is at least 7 times more potent than EACA on a molar basis, so less of the former drug is required.
Boese et al. conclude that “TXA does not have superior blood conservation effects or safety profile compared with EACA in TKA,” but they cite a need for future equivalence, superiority, and noninferiority trials with these drugs.