Abstract
Introduction
Rivaroxaban, an oral factor Xa inhibitor, has been approved by USFDA for prophylaxis of deep vein thrombosis (DVT) and pulmonary embolism (PE) in hip and knee arthroplasties. Its indication in hip fracture surgery has been recently recommended in Asian venous thromboembolism (VTE) guidelines. Phase II dose-ranging study demonstrated that 5 mg rivaroxaban is as effective as enoxaparin for VTE prophylaxis with lower incidence of bleeding complication than the recommended 10 mg dose. Rivaroxaban is recommended to be given 6–8 hours after operation. However, many surgeons are hesitated to follow this guideline since it might increase post-operative blood loss and wound complication. Elderly patients, such as hip fracture patients, are generally at more risk of bleeding and wound complications. These patients may benefit from using the delayed and reduced-dose regimen.
Methods
Since July 2011, all eligible hip fracture patients treated by single group of surgeons were given 5mg daily dose of rivaroxaban for VTE prophylaxis. Initial dose of rivaroxaban was given after drain had been removed (24–36 hours post-operatively) and continued for 14 days. Inclusion criteria are femoral neck fracture or intertrochanteric fracture in patients age 60 and over. Exclusion criteria are pathologic fracture, reoperation for failed fixation, chronic anticoagulant therapy, and allergy to rivaroxaban. Criteria by Aniwan and Rojnackarin were used for clinical diagnosis of DVT and PE. Suspected case of DVT and PE were sent for confirmation with Doppler U/S and Pulmonary Artery CT scan, respectively. All bleeding and wound complications were recorded. Numbers of blood transfusion were also recorded. Patients were followed for at least 6 weeks, all complications were recorded.
Results
There were 79 hip fracture patients matching our criteria. They were composed of 54 femoral neck fractures and 25 intertrochanteric fractures. Mean age of patients was 76.3 years. All femoral neck fractures were treated with bipolar hemiarthroplasty and intertrochanteric fractures were treated with short cephalomedullary nail. Two patients (2.6%) were compatible with clinical criteria of DVT. However, Doppler ultrasound examinations do not demonstrate thrombus or intraluminal filling defect. There was no suspected case of PE. There was no major hemorrhagic wound complication requiring reoperation. Minor wound complications include 7 (8.9%) cases of prolong serous oozing and 1 (1.3%) superficial wound infection. Extrasurgical site bleeding includes 1 (1.3%) upper GI bleeding and 2 (2.5%) hematuria. None of the patients received more than 2 units of blood transfusion.
Discussion and Conclusion
Delayed and reduced-dose regimen of rivaroxaban is effective for VTE prophylaxis in hip fracture patients. There is no major hemorrhagic wound complication. Nonetheless, extrasurgical site bleeding is frequent. Further randomized comparative study with larger number of patients should be performed to demonstrate whether the benefits of the modified regimen existed or not.
