Abstract
Introduction
Oral factor Xa inhibitors have recently been licensed for use as thromboprophylaxis in arthroplasty surgery. Phase IV trials have proven there efficacy in DVT/PE prevention with comparable rates in major adverse events, including major bleeding. We examined whether the introduction of rivaroxoban, an oral factor Xa inhibitor, increased total blood loss in patients undergoing primary arthroplasty surgery.
Methods
Two groups were studied. The intervention group were prescribed rivaroxoban thrombophrophylaxis 6–10 hours post-surgery, and the control group were prescribed low molecular weight heparin (daltaparin 5,000u) 6–10 hours post-surgery. All other factors were kept constant.
Pre- and post-operative haemoglobin levels (post-operative day 2) were recorded. Any requirement for transfusion was also documented. Actual drop in haemoglobin levels was compared between the two groups.
Results
91 patients were prescribed rivaroxoban (48 THR and 43 TKR), and 71 were included in the control group (34 THR and 37 TKR). Baseline pre-operative haemoglobin were comparable (p=0.43; 13.0 vs 13.2g/dL), however, post-operative blood loss was significantly increased in the rivaroxoban group (p=< 0.0001; 3.6 vs 2.8g/dL).
Total knee replacements had a significant increase in post-operative blood loss in the rivaroxoban group (p=< 0.0001; 3.4 vs 2.6g/dL). Total hip replacement surgery had an increase in total blood loss in the rivaroxoban group, but this did not reach statistical significance (p=0.33; 3.8 vs 3.3g/dL).
More patients undergoing TKR required transfusion in the rivaroxoban group (0.07% vs 0.03%).
Conclusions
Oral factor Xa inhibitors significantly increase post-operative blood loss in total knee arthroplasty surgery when compared with LMWH. There is a subsequent increased requirement for blood transfusion and the potential complications related to bleeding and transfusion. These factors must be considered and balanced with the ease of oral anticoagulation when introducing these newer agents in arthroplasty patients
