1Rush University Medical Center, Chicago, Illinois.
J Bone Joint Surg Am. 2017 Mar 1;99(5):373-378. doi: 10.2106/JBJS.16.00188.
Tranexamic acid is an antifibrinolytic that has been shown to reduce blood loss and the need for transfusions when administered intravenously in total hip arthroplasty. Oral formulations of the drug are available at a fraction of the cost of the intravenous preparation. The purpose of this randomized controlled trial was to determine if oral and intravenous formulations of tranexamic acid have equivalent blood-sparing properties.
In this double-blinded trial, 89 patients undergoing primary total hip arthroplasty were randomized to receive 1.95 g of tranexamic acid orally 2 hours preoperatively or a 1-g tranexamic acid intravenous bolus in the operating room prior to incision; 6 patients were eventually excluded for protocol deviations, leaving 83 patients available for study. The primary outcome was the reduction of hemoglobin concentration. Power analysis determined that 28 patients were required in each group with a ±1.0 g/dL hemoglobin equivalence margin between groups with an alpha of 5% and a power of 80%. Equivalence analysis was performed with a two one-sided test (TOST) in which a p value of <0.05 indicated equivalence between treatments.
Forty-three patients received intravenous tranexamic acid, and 40 patients received oral tranexamic acid. Patient demographic characteristics were similar between groups, suggesting successful randomization. The mean reduction of hemoglobin was similar between oral and intravenous groups (3.67 g/dL compared with 3.53 g/dL; p = 0.0008, equivalence). Similarly, the mean total blood loss was equivalent between oral and intravenous administration (1,339 mL compared with 1,301 mL; p = 0.034, equivalence). Three patients (7.5%) in the oral group and one patient (2.3%) in the intravenous group were transfused, but the difference was not significant (p = 0.35). None of the patients in either group experienced a thromboembolic event.
Oral tranexamic acid provides equivalent reductions in blood loss in the setting of primary total hip arthroplasty, at a greatly reduced cost, compared with the intravenous formulation.
Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.
氨甲环酸是一种抗纤维蛋白溶解剂，已被证明在全髋关节置换术中静脉内给药时可减少失血和输血需求。该药物的口服制剂的成本仅为静脉制剂的一小部分。本随机对照试验的目的是确定氨甲环酸的口服和静脉制剂是否具有等效的血液保护特性。
在这项双盲试验中，89 例接受初次全髋关节置换术的患者被随机分为两组，分别在术前 2 小时口服 1.95g 氨甲环酸或在手术切口前静脉内给予 1g 氨甲环酸；最终有 6 例患者因违反方案而被排除，共有 83 例患者可供研究。主要结局是血红蛋白浓度的降低。功效分析确定每组需要 28 例患者，两组之间血红蛋白等效边际为±1.0g/dL，α值为 5%，功效为 80%。等效性分析采用双单侧检验（TOST）进行，当 p 值<0.05 时表示两种治疗方法等效。
43 例患者接受静脉内氨甲环酸治疗，40 例患者接受口服氨甲环酸治疗。两组患者的人口统计学特征相似，提示随机分组成功。口服组和静脉组的血红蛋白平均降低量相似（3.67g/dL 比 3.53g/dL；p=0.0008，等效）。同样，口服组和静脉组的总失血量也相当（1339ml 比 1301ml；p=0.034，等效）。口服组有 3 例（7.5%）患者和静脉组有 1 例（2.3%）患者需要输血，但差异无统计学意义（p=0.35）。两组均无患者发生血栓栓塞事件。
与静脉制剂相比，口服氨甲环酸在初次全髋关节置换术中可同等程度地减少失血，且成本大大降低。
治疗性 I 级。请参阅作者说明，以获取完整的证据水平描述。
