Abstract
Introduction
Patients undergoing total knee arthroplasty (TKA) are at high risk of post operative venous thromboembolism (VTE). Edoxaban, the oral direct and selective factor Xa inhibitor, is available for preventing VTE after TKA. Recently, patients often take antiplatelet drugs including aspirin for their past illness. In our hospital, patients, in general, undergoing TKA receive edoxaban, but patients with aspirin for past illness receive only aspirin for preventing VTE. The aim of this study was to compare edoxaban and aspirin for preventing VTE in patients undergoing TKA.
Materials and methods
From April 2012 to March 2014, 137 patients underwent primary TKA under general anesthesia with epidural anesthesia or femoral/ sciatic nerve block. Patients were excluded following; (1) renal dysfunction, (2) have taken anticoagulants such as warfarin for past illness. Finally, a total of 120 patients were enrolled.
At the surgery, tourniquet was inflated and mid-vastus approach was used. After prosthesis implantation, tourniquet was deflated and drain tube was inserted. Intra and after operation, an intermittent pneumatic compression device was used.
At postoperative day 2, edoxaban or aspirin started after removal of epidural anesthesia or drainage tube. Ninety-seven patients were assigned to receive edoxaban once daily (group E), and the rest of 23 received aspirin again same as before (group A). Edoxaban were scheduled to continue for 10 days.
DVT diagnosis
At postoperative day 7, compression and colored Doppler imaging was taken for bilateral common femoral veins, superficial veins, popliteal veins and calf veins by skilled clinical technologist. Augmentation by calf squeezing and by dropped lower leg down were included. Diagnosing DVT criteria was loss of vein compressibility, presence of intraluminal echogenicity and absence of venous flow.
D-dimer levels
At preoperative, postoperative days 7 and 14, plasma D-dimer levels were measured.
Statistical analysis
Data were compared using independent t-test or the chi-square test. A significant difference was set at p<0.05.
Results
Patients’ characteristics were shown in table 1. Age in the group A was significantly higher than in the group E.
The total incidence of DVT was 40%. The incidence of DVT was significantly decreased in group E compared to group A at day 7 (group E: 34% versus group A: 65%, p<0.01) (table 2).
The D-dimer level in group E was significantly decreased at postoperative day 7 (13.2 ± 6.8 (mean ± SD) vs 17.0 ± 9.1, p<0.05). At day 14, there were no significant differences (Figure 1).
Discussion
In this study, edoxaban decreased the incidence of DVT after TKA compared to aspirin. The result of D-dimer supported the efficacy of edoxaban. Results showed that edoxaban is effective for preventing DVT following TKA.
Recently, TKA patients often take antiplatelet drugs including aspirin for their past illness. It is still controversial to add an antithrombotic drug for preventing VTE. The incidence of DVT with aspirin was higher than that with edoxaban. Thus, patients received only aspirin might be needed not only to pay attention to VTE, but also to add anticoagulants as edoxaban for preventing VTE.
