Apixaban versus enoxaparin in the prevention of venous thromboembolism following total knee arthroplasty: a single-centre, single-surgeon, retrospective analysis

Current Evidence and Expert Opinion on Thromboprophylaxis After Total Knee and Hip Replacement

An effective anticoagulant provides a balance between the risk for venous thromboembolism (VTE) and bleeding and is crucial in achieving optimal clinical outcomes in patients undergoing total hip replacement (THR) and total knee replacement (TKR) surgeries. We performed a review of the literature on thromboprophylaxis for patients undergoing total hip or knee replacement. This review article summarizes current guidelines and evidence for anticoagulation along with the expert opinion about pharmacological VTE prophylaxis, particularly non-Vitamin K antagonist oral anticoagulants (NOACs), for patients after total hip or knee replacement. Aspirin for VTE prophylaxis after TKR/THR has been controversial and most of the evidence is reported from observational research. Although the guidelines do not recommend any specific thromboprophylaxis agent, available evidence suggests that NOACs are as effective as low molecular weight heparins (LMWHs) in preventing VTE. Oral administration and the lack of dose monitoring make NOACs easy to use in outpatient settings in cases with challenging treatment compliances. They can be used for two weeks after TKR and five weeks after THR - six weeks after TKR and THR to cover the at-risk period for VTE post-discharge. Owing to the lack of evidence for a head-to-head comparison of NOACs, an anticoagulant with better efficacy and safety may be suggested in special patient populations (elderly, obese patients, or those with renal dysfunction). The expert opinion on pharmacological VTE prophylaxis provided in this article could address some gaps in the management of anticoagulation in patients with total hip or knee replacement.

Is Apixaban Safe and Effective for Venous Thromboembolism Prophylaxis After Primary Total Hip and Total Knee Arthroplasties?

BACKGROUND

Venous thromboembolism (VTE) is a serious complication of total hip arthroplasty (THA) and total knee arthroplasty (TKA). Apixaban is approved for VTE prophylaxis. This study seeks to ascertain the risk of VTE and bleeding complications in patients undergoing primary THA and TKA receiving apixaban for postoperative VTE prophylaxis for one of the following indications: high risk for VTE, previously on apixaban, and contraindication to the use of aspirin.

METHODS

This is a retrospective cohort study of patients who underwent primary THA or TKA over a 17-month period and were prescribed apixaban for thromboprophylaxis postoperatively.

RESULTS

230 patients were included in the study, 110 TKA and 120 THA. The primary reasons for high-risk VTE status included personal and family history of VTE, and 13% were taking apixaban preoperatively for atrial fibrillation. 1 patient (0.43%) who underwent TKA had a DVT with PE. 2.6% of patients had wound complications requiring operative treatment, and 0.87% of THA patients underwent revision arthroplasty.

CONCLUSION

The use of apixaban for VTE prophylaxis after primary THA and TKA in patients at high risk for VTE, in patients previously on apixaban, and in patients with a contraindication to the use of aspirin is associated with a low risk of VTE and bleeding complications.

Real-world effectiveness and safety of pharmacological thromboprophylaxis in patients undergoing primary total hip and knee arthroplasty: A narrative review

In this narrative review of the real-world effectiveness and safety of pharmacological thromboprophylaxis following primary total hip and knee arthroplasty, a total of 12 non-interventional observational studies were included. Pharmacological thromboprophylaxis included warfarin, heparins, dabigatran, rivaroxaban, apixaban, acetylsalicylic acid, and fondaparinux. The absolute risks varied across the included studies. These variations can be explained by differences in patient populations, drug exposure, follow-up time, and definition of outcomes, which makes it a challenge to compare the risk estimates. These findings emphasize the need for a large population-based real-world study to provide comparable risk estimates associated with different pharmacological thromboprophylaxis.

Comparison of Apixaban and Low Molecular Weight Heparin in Preventing Deep Venous Thrombosis after Total Knee Arthroplasty in Older Adults

PURPOSE

To compare the effect of apixaban and low molecular weight heparin (LMWH) in the prevention and treatment of deep venous thrombosis (DVT) after total knee arthroplasty in older adult patients.

MATERIALS AND METHODS

A total of 220 patients (average age of 67.8±6.4 years) undergoing total knee arthroplasty were randomly selected as research subjects and were divided into apixaban and LMWH groups (110 in each group).

RESULTS

The incidence of DVT was lower in the apixaban group than in the LMWH group (5.5% vs. 20.0%, p=0.001). Activated partial thromboplastin times (35.2±3.6 sec vs. 33.7±2.2 sec, p=0.010; 37.8±4.6 sec vs. 34.1±3.2 sec, p<0.001; 39.6±5.1 sec vs. 35.7±3.0 sec, p=0.032) and prothrombin times (14.0±1.0 sec vs. 12.8±0.9 sec, p<0.001; 14.5±1.2 sec vs. 13.0±1.1 sec, p<0.001; 15.3±1.4 sec vs. 13.2±1.3 sec, p=0.009) in the apixaban group at 1 week after surgery, 3 weeks after surgery, and the end of treatment were higher than those in the LMWH group. Platelet and fibrinogen levels in the apixaban group were lower than those of the LMWH group. Also, capillary plasma viscosity and erythrocyte aggregation in the apixaban group at 1 week after surgery, 3 weeks after surgery, and the end of treatment were lower than those in the LMWH group.

CONCLUSION

Apixaban, which elicits fewer adverse reactions and is safer than LMWH, exhibited better effects in the prevention and treatment of DVT after total knee arthroplasty in older adults.

A comparative cost-effectiveness analysis of mechanical and pharmacological VTE prophylaxis after lower limb arthroplasty in Australia

BACKGROUND

Venous thromboembolism (VTE) is a complication following surgery. Low-molecular-weight heparin (LMWH) or direct oral anticoagulants (DOACs) are efficacious but come with inherent bleeding risk. Mechanical prophylaxis, such as intermittent pneumatic compression (IPC), does not induce bleeding but may be difficult to implement beyond the immediate post-operative period. This study compared the cost and quality-adjusted life years (QALYs) saved of commonly used VTE prophylaxis regimens after lower limb arthroplasty.

METHODS

A previously published cost-utility model considering major efficacy and safety endpoints was updated to estimate the 1-year cost-effectiveness of different VTE prophylaxis regimens. The VTE strategies assessed included apixaban, dabigatran, rivaroxaban, LMWH, IPC, IPC + LMWH and IPC + apixaban. Efficacy data were derived from studies in PubMed, and cost data came from the 2017 Australian AR-DRG and PBS pricing schemes.

RESULTS

Costs for VTE prophylaxis including treatment of its associated complications over the first year after surgery ranged from AUD $644 (IPC) to AUD $956 (rivaroxaban). Across 500 simulations, IPC was the cheapest measure in 73% of simulations. In 97% of simulations, a DOAC was associated with the highest resulting QALYs. Compared to IPC, apixaban was cost-effective in 76.4% of simulations and apixaban + IPC in 87.8% of simulations. For VTE events avoided, the DOACs and IPC were on par. LMWH and LMWH + IPC were negatively dominated.

CONCLUSIONS

Apixaban, IPC or a sequential/simultaneous combination of both is currently the most cost-effective VTE prophylaxis regimens. The choice between them is best guided by the relative VTE and bleeding risks of individual patients.

Intermittent pneumatic compression is a cost-effective method of orthopedic postsurgical venous thromboembolism prophylaxis

Background

Venous thromboembolism (VTE) is a major complication after lower-limb arthroplasty that increases costs and reduces patient’s quality of life. Using anticoagulants for 10–35 days following arthroplasty is the standard prophylaxis, but its cost-effectiveness after accounting for bleeding complications remains unproven.

Methods

A comprehensive, clinical model of VTE was created using the incidences, clinical effects (including bleeding), and costs of VTE and prophylaxis from randomized controlled trials, meta-analyses, and large observational studies. Over 50 years, the total health care costs and clinical impact of three prophylaxis strategies, that are as follows, were compared: low-molecular-weight heparin (LMWH) alone, intermittent pneumatic compression (IPC), and IPC with LMWH (IPC+LMWH). The cost per VTE event that was avoided and cost per quality-adjusted life year (QALY) gained in both the US and Australian health care settings were calculated.

Results

For every 2,000 patients, the expected number of VTE and major bleeding events with LMWH were 151 and 6 in the USA and 160 and 46 in Australia, resulting in a mean of 11.3 and 9.1 QALYs per patient, respectively. IPC reduced the expected VTE events by 11 and 8 in the USA and Australia, respectively, compared to using LMWH alone. IPC reduced major bleeding events compared to LMWH, preventing 1 event in the US and 7 in Australia. IPC+LMWH only reduced VTE events. Neither intervention substantially impacted QALYs but both increased QALYs versus LMWH. IPC was cost-effective followed by IPC+LMWH.

Conclusion

IPC and IPC+LMWH are cost-effective versus LMWH after lower-limb arthroplasty in the USA and Australia. The choice between IPC and IPC+LMWH depends on expected bleeding risks.