Letter to the editor on “Combined use of tranexamic acid and rivaroxaban in posterior lumbar interbody fusion safely reduces blood loss and transfusion rates without increasing the risk of thrombosis—a prospective, stratified, randomized, controlled trial”

Abstract

Dear Editor, We read with great interest the article entitled “Combined use of tranexamic acid and rivaroxaban in posterior lumbar interbody fusion safely reduces blood loss and transfusion rates without increasing the risk of thrombosis—a prospective, stratified, randomized, controlled trial” by Zhang et al. [1]. This research is valuable and instructive for clinical practice; the authors deserve accolades for their wonderful work. However, we have some questions that we would like to communicate with the authors. Firstly, the total amount of blood loss (TBL) was calculated using the modified Gross formula via the difference between pre-operative haematocrit (HCT) and postoperative HCT on the first day after surgery in this study. However, TBL should be calculated via minimum postoperative HCT because previous studies have shown that haemoglobin (Hb) and HCT level reach a minimum on post-operative days 3~4 [2]. Meanwhile, the volume of autologous and allogenic transfusion should also be added to calculate TBL [2]. In addition, it was not stated the formula for calculating hidden blood loss. Also, the authors stated that there were significant differences in BMI between groups A and B and groups C and D, which will affect the calculation of TBL. We think the above mentioned aspects need to be clarified by the authors, or which could lead to deviation in calculating blood loss. Secondly, the authors chose to use “low dose”-1g intravenous TXA in this study, which was deemed sufficient. However, both Kim [3] and Yuan [4] concluded that the effectiveness of TXA in reducing peri-operative blood loss in a dose-dependent manner. In this study, the dose of TXA resulted in patients with higher body mass getting a much lower effective dose of TXA than patients with lower body mass, which will result in difference in reducing blood loss. If the authors used TXA according to the patient’s weight, the readers will be a better understanding of the effective dose of TXA that the patients actually received. Finally, the patients were diagnosed with isolated distal venous thromboembolism (VTE) by routine ultrasound examinations in this study, but it was not stated whether the patients were examined ultrasound at the same time or the exact timing. According to the previous study, the timing of deep vein thrombosis (DVT) after PLIF was five to 16 days after surgery [5]. Therefore, DVT will not be effectively detected if the detection is too early, which will significantly affect the incidence of DVT after surgery. We appreciate that Zhang et al. provided us with an interesting research of combining the use of TXA and rivaroxaban in PLIF. However, if the authors clarified the above points, it could add more to the explicitness of their discussion and be helpful for clinical practice and further research. * Qingquan Kong [email protected]