Oral thromboprophylaxis following total hip or knee replacement: review and multicentre experience with dabigatran etexilate

Direct Oral Anticoagulants Are a Potential Alternative to Low-Molecular-Weight Heparin for Thromboprophylaxis in Trauma Patients Sustaining Lower Extremity Fractures

BACKGROUND

Trauma patients are at a significant risk of venous thromboembolism (VTE), with lower extremity fractures (LEF) being independent risk factors. Use of direct oral anticoagusants (DOACs) for VTE prophylaxis is effective in elective orthopedic surgery, but currently not approved for trauma patients. The primary objective of this study was to compare the effectiveness and safety of thromboprophylaxis of DOACs with low-molecular-weight heparin (LMWH) in trauma patients sustaining LEF.

MATERIALS AND METHODS

We included adult trauma patients admitted to trauma quality improvement program participating trauma centers (between 2013 and 2016), who sustained LEF and were started on DOACs or LMWH for thromboprophylaxis after admission. Propensity score matching was performed to compare symptomatic VTE and bleeding control interventions between the groups.

RESULTS

Of 1,009,922 patients in trauma quality improvement program, 167,640 met inclusion criteria (165,009 received LMWH and 2631 received DOACs). After propensity score matching, 2280 predominantly elderly (median age: 67 y) isolated femur fracture patients (median ISS: 10) were included in each group (4560 patients in total). Symptomatic VTE occurred in 1.4% of patients in both matched groups (P = 0.992). Bleeding control interventions occurred less often in the DOAC group, albeit statistically insignificant (5.8% versus 6.0%, P = 0.772).

CONCLUSIONS

This study found similar rates of VTE and bleeding control measures for thromboprophylaxis with DOACs or LMWH in matched trauma patients with LEF. Further prospective research is warranted to consolidate the safety of DOAC thromboprophylaxis in trauma patients with LEF. Favorable oral administration and likely increased adherence could benefit this high-risk population.

Benefit–risk profile of non-vitamin K antagonist oral anticoagulants in the management of venous thromboembolism

The prevention and treatment of venous thromboembolism (VTE) remains a clinical challenge, primarily owing to drawbacks associated with the use of heparins and vitamin K antagonists (VKAs). These and other factors, including a growing elderly population, mean that VTE presents a continuing burden to patients and physicians. Anticoagulant therapy is a fundamental approach for VTE management. Non- VKA oral anticoagulants, including the factor Xa inhibitors apixaban, edoxaban and rivaroxaban, and the thrombin inhibitor dabigatran, have been studied in phase III trials across a spectrum of thromboembolic disorders. These agents offer simplified care, with similar or improved efficacy and safety outcomes compared with heparins and vitamin K antagonists. There are several factors a physician must consider when prescribing an anticoagulant. An important consideration with all anticoagulant use is bleeding risk, especially in high-risk groups such as the elderly or those with renal impairment or cancer. In orthopaedic patients, other risks include a need for surgical revision or blood transfusion, or wound complications. Therefore, the clinical benefits of an anticoagulant should ideally be balanced with any risks associated with the therapy. Quantitative benefit–risk assessments are lacking, and owing to differences in trial design the non-VKA oral anticoagulants cannot be compared directly. Based on trial and “reallife” data, this review will summarise the clinical data for the non-VKA oral anticoagulants in the prevention and treatment of VTE, focusing on the balance between the benefits and risks of anticoagulation with these drugs, and their potential impact on VTE management.

DOACs - advances and limitations in real world

The group of new oral anticoagulants or NOACs, now termed direct oral anticoagulants or DOACs, with their favourable results from large scale phase III clinical trials, represent a major advancement and expanded armamentarium in antithrombotic therapy. Dabigatran, rivaroxaban, apixaban and edoxaban are now in clinical routine use for prevention and treatment of arterial and venous thrombotic diseases as addressed in their clinical trials. Usage of the DOACs is expected to increase as clinicians gain more experience and reassurance with data from the real world studies which are generally consistent with that from clinical trials. Development of specific antidotes in management of bleeding complications and development of coagulation assays for their plasma levels will further boost the confidence in the DOACs. Nonetheless, there are still limitations associated with the DOACs. Many patients in need of anticoagulant therapy for indications not studied in the clinical trials will not be eligible for treatment with a DOAC. Conditions where more data is required include DOACs use in the paediatric age group, patients with atrial fibrillation and valvular heart disease, thrombosis associated with the anti-phospholipid syndrome and cancer associated thrombosis. The affordability and access to these drugs may pose an issue for many patients under healthcare systems not providing for these medications. With four new anticoagulants coming onboard very quickly, the focus has shifted to the practical approach and management in real life as many clinicians are not yet familiar with the DOACs. Clinicians need to be educated on how to manage this new class for drugs, from choosing the appropriate drug to prevention and managing bleeding complications as a lack of knowledge and understanding in these drugs will lead to inappropriate use and compromise on patient safety.

Real-world data confirm clinical trial outcomes for rivaroxaban in orthopaedic patients

Venous thromboembolism (VTE) is a potential cause of morbidity and mortality in patients after major orthopaedic surgery. Based on the results of the international phase III RECORD (Regulation of Coagulation in Orthopaedic Surgery to Prevent Deep Vein Thrombosis and Pulmonary Embolism) program, the oral, direct Factor Xa inhibitor rivaroxaban has been approved in many countries for the prevention of VTE after elective hip arthroplasty or knee arthroplasty. However, study results of randomized controlled trials may have limited generalizability to routine clinical practice in unselected patients. The phase IV XAMOS (Xarelto® in the Prophylaxis of Postsurgical Venous Throboembolism after Elective Major Orthopaedic Surgery of the Hip or Knee) study and the ORTHO-TEP (large single-center registry) collected real-world data to assess the effectiveness and safety of rivaroxaban compared with standard of care in large cohorts of patients undergoing major orthopaedic surgery. This review evaluates real-world data from XAMOS and ORTHO-TEP, confirming the favorable benefit–risk profile of rivaroxaban for the prevention of VTE in patients after major orthopaedic surgery that was demonstrated by the phase III RECORD studies in patients after elective hip or knee arthroplasty.

Hip arthroplasty fatality related to dabigatran induced gastrointestinal haemorrhage

We report a fatality due to massive gastrointestinal haemorrhage in a patient receiving prophylactic dabigatran etexilate following a total hip replacement. A 79-year-old woman was commenced on dabigatran for venous thromboembolic prophylaxis following a total hip replacement. She presented again four days after surgery with haematemesis and hypotension but her coagulopathy could not be corrected, leading to her death. This case highlights the lack of reversal agent for dabigatran etexilate that resulted in this fatal complication.