Abstract
Background
Thromboembolic disease is a common complication of total hip replacement (THR). The administration of postoperative anticoagulants is therefore highly recommended. The purpose of this study was to compare rivaroxaban with fondaparinux with regards to their safety and effectiveness for the prevention of venous thromboembolic events (VTE) after THR.
Methods
We conducted an independent prospective study comparing VTE prevention strategies in two successive series of patients (Groups A and B) undergoing elective unilateral THR. Group A (n=253) received fondaparinux daily 2.5 mg for 10 days, followed by tinzaparin 4500 IU daily for one month. Group B (n=229) received 10 mg rivaroxaban daily for 40 days without platelet monitoring.
All surgeries were performed by a single surgeon under general anesthesia using an active blood transfusion-sparing plan. In the absence of contraindications, patients received intra-operative administration of tranexamic acid to reduce postoperative bleeding.
Preoperative and postoperative hemoglobin levels were recorded at regular intervals. Bleeding events were documented. The bleeding index was calculated by adding the number of red blood cell units and the difference in the hemoglobin level (in g/dL) between the first morning after the day of surgery and the seventh postoperative day (POD 7). After 5 to 10 days, all patients underwent bilateral lower-extremity duplex ultrasonography to screen for deep venous thrombi. Any clinical symptoms of pulmonary embolism were evaluated with spiral computed tomography lung scans. Clinical evaluation to look for evidence of deep venous thrombi and pulmonary emboli was performed at eight weeks postoperatively.
Results
Baseline characteristics between the two groups were comparable. The rate of major bleeding events, proximal deep venous thrombi, and pulmonary emboli was nil in each group. The incidence of blood transfusion was 0.8% in Group A (2 of 253 hips) and 0.4% (1 of 229 hips) in Group B (p=1.0).
The bleeding index analysis excluded 8 hips for which the hemoglobin value at POD 7 was not measured. The bleeding index was 1.03 (standard deviation, 0.88) in Group A and 0.8 (standard deviation, 0.80) in Group B (p<0.001). The incidence of bleeding index >2 was 10.5% (27 of 247 hips) in Group A and 3% (7 of 227 hips) in Group B (p<0.001).
Discussion
We compared two series of patients treated with THR undertaken with postoperative anticoagulation to prevent VTE. The high level of success these anticoagulant treatments had at preventing VTE in our series could be attributed at least partially to the combination of an active blood-sparing transfusion plan with the use of anticoagulant molecules reported in the literature to be quite potent.
Conclusions
This prospective study comparing two anticoagulant regimens in patients treated with THR did not detect any difference with regards to the efficacy of the treatments, although there was significantly less bleeding index in patients who received rivaroxaban.
