Abstract
Introduction
In Japan, edoxaban has been used for the prevention of venous thromboembolism (VTE) after total knee arthroplasty (TKA) since June 2011. Edoxaban is an oral direct factor Xa inhibitor, expected to be more convenient for the postoperative treatment of TKA. Enoxaparin, a II and Xa inhibitor, was approved in Japan for the prevention of VTE in patients undergoing orthopedics surgery from 2008. In this study, the effect for the prevention of VTE after TKA was compared between these two drugs in Japanese patients.
Patients and Methods
We studied 42 Japanese patients who underwent TKA from May 2011 to April 2012. The operations were performed under general anesthesia, continuous femoral nerve block, an air tourniquet, and using cements for implant fixation. These patients were divided in two groups, use of 30 mg edoxaban once daily (ED group), and use of 1000 IU of enoxaparin twice daily (EN group). The initial dose was administered between 12 and 21 hours after surgery. We compared the incidence of VTE, bleeding complications, D dimer levels, and hemoglobin (Hb) loss. The screening of VTE was performed by enhanced CT scan screening from the chest to the foot on postoperative day 5 or 6 in all patients. The bleeding complication was divided into major bleeding and minor bleeding with Japanese guideline for the prevention of VTE. D dimer levels and Hb levels were preoperatively and postoperative day 1, 3, 5, 7, and 14. The loss of Hb was calculated from preoperative Hb level minus lowest postoperative Hb level.
Results
The following results is showed in the order as ED group, EN group. The incidence of VTE was 45%, 32%, that was higher in ED group (see figure 1). There were almost no differences between both groups about D dimer levels and Hb loss in follow up period (see figure 2, 3). There were no major bleeding in both groups. The incidence of minor bleeding were 20%, 32%, that was higher in EN group (see figure 4).
Discussion
We compared the effect of edoxaban and enoxaparin for the prevention of VTE. These two drugs are different way of administration. Edoxaban is administered orally, on the other enoxaparin requires with hypodermic injection. Therefore edoxaban is expected to be more convenient and less complaints than enoxaparin for the prevention of VTE. However our study showed that the use of 30 mg edoxaban once daily was less efficacy than the use of enoxaparin 1000 IU twice daily. The bleeding complication was lower incidence in the edoxaban, thus consideration should be given to the administration dosage of edoxaban to Japanese patients.
