Abstract
Aims
This phase II safety study aimed to investigate the bleeding side effect profile in patients treated with Rivaroxaban as a new agent for venous thromboembolism (VTE) prophylaxis following hip or knee arthroplasty.
Methods
A retrospective study of complications was conducted in 88 consecutive patients undergoing hip and knee arthroplasty at one centre. Patients received chemical and/or mechanical VTE prophylaxis according to local guidelines. Data was collected from notes and evaluated using Fisher's exact test and t-Test. Significance was determined if p< =0.05. The primary end-point was local wound site oozing or bleeding. Secondary end-points were drop in haemoglobin, drain output and infection.
Results
55 patients were treated with Rivaroxaban, 18 with mechanical prophylaxis only, 10 with Enoxaparin and 5 with aspirin, clopidogrel or warfarin. The Rivaroxaban cohort demonstrated a statistically significant amount of increased major bleeding (24% vs. 0% p=0.03) and wound oozing (27% vs. 0% p=0.02) when compared to patients treated with Enoxaparin. Compared to those treated with other methods of VTE prophylaxis, Rivaroxaban also significantly increased major bleeding (24% vs. 6% p=0.01) and wound oozing (27% vs. 12% p=0.03). The Rivaroxaban cohort demonstrated a significantly larger drop in haemoglobin compared to the combined non-Rivaroxaban group (3.0 vs. 2.4 g/dL p=0.04). There was no significant difference in drain volume or rate of infection between groups.
Conclusions
Rivaroxaban appears to cause increased wound site bleeding in comparison to Enoxaparin and other methods of thromboembolism prophylaxis. Further use of Rivaroxaban at this centre was therefore discontinued; however, the small group sizes and retrospective non-randomised design of this study introduce bias and limit the reliability of its findings. Prospective randomised controlled trial focused on wound complications is required to eliminate selection and reporter biases.
