Oral direct factor Xa inhibitor versus enoxaparin for thromboprophylaxis after hip or knee arthroplasty: Systemic review, traditional meta-analysis, dose-response meta-analysis and network meta-analysis

Comparison of efficacy and safety between aspirin and oral anticoagulants for venous thromboembolism prophylaxis after major orthopaedic surgery: a meta-analysis of randomized clinical trials

Background: venous thromboembolism (VTE) is one of the most common complications after major orthopaedic surgery. Recent studies have suggested that aspirin may also be effective in preventing VTE, but it is still controversial whether it can be routinely used. Objectives: To compare the efficacy and safety of aspirin against oral anticoagulants in the prevention of VTE following total hip arthroplasty (THA), total knee arthroplasty (TKA) or hip fracture surgery (HFS). Methods: Relevant publications have been obtained using electronic search databases such as PubMed, Embase, Web of Science, Cochrane Library, and Clinical Trials. gov. from inception to 20 July 2023. Only RCTs evaluating the efficacy and safety of aspirin compared with oral anticoagulants undergoing major orthopaedic surgery were included in the meta-analysis. The primary outcome reported was any VTE event (including deep vein thrombosis (DVT) and pulmonary embolism (PE)). Secondary outcomes included mortality, major bleeding (including gastrointestinal bleed, cerebrovascular hemorrhage, or any bleeding requiring a return to the theater), minor bleeding (ecchymosis, epistaxis, hematuria), and wound complications. The risk of bias for all included studies was assessed according to the Cochrane Collaboration's tool. Results: After screening 974 studies, 12 randomized clinical trials (RCTs) were included, involving 5,088 participants, including 2,540 participants in aspirin, 2,205 participants in rivaroxaban, and 323 participants in warfarin. Aspirin was found to be less effective than oral anticoagulants in thromboprophylaxis after major orthopedic surgery (RR = 1.206, 95% CI 1.053-1.383). After subgroup analysis according to the type of oral anticoagulant, the results showed that aspirin was similar to rivaroxaban and inferior to warfarin. Considering that the studies in the warfarin group were all conducted before 2000, our results need to be further confirmed. In addition, the aspirin group had a higher risk of VTE than the control group in other subgroups, including a follow-up time of ≤3 months, type of procedure as TKA, high-dose aspirin (≥650 mg qd), and no combined use of mechanical prophylaxis. In terms of safety events, aspirin did not show significant differences in major bleeding (RR = 0.952, 95% CI 0.499-1.815), all-cause mortality (RR = 1.208, 95% CI 0.459-3.177), and wound-related events (RR = 0.618, 95% CI 0.333-1.145) compared with oral anticoagulants, and aspirin was associated with a reduction in the risk of minor bleeding (RR = 0.685, 95% CI 0.552-0.850) events and total bleeding (RR = 0.726, 95% CI 0.590-0.892). Conclusion: Aspirin reduces bleeding risk after major orthopedic surgery compared with oral anticoagulants, but may sacrifice VTE prevention to some extent. Updated evidence is needed to analyze the thromboprophylaxis effects of aspirin in patients undergoing major orthopedic surgery. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=463481, identifier CRD42023463481.

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.

Rivaroxaban versus enoxaparin for thromboprophylaxis in orthopedic surgery: A meta-analysis

INTRODUCTION

Venous thromboembolism is highly associated with orthopedic surgery, so thromboprophylaxis is an important consideration for orthopedic surgeons. The new oral anticoagulants have clear advantages for clinical practice.

OBJECTIVES

To analyze the efficacy and safety of rivaroxaban versus enoxaparin for thromboprophylaxis in different orthopedic surgeries.

MATERIAL AND METHODS

Systematic electronic search of clinical trials was carried out. Data extraction of efficacy outcomes (deep venous thrombosis, pulmonary embolism and death) and safety outcomes (major bleeding and clinical relevant bleeding) was realized.

RESULTS

Six randomized and controlled clinical trials were included in this meta-analysis. Compared with enoxaparin the risk of venous thromboembolism was lower with rivaroxaban both in different orthopedic surgeries (RR: 0.51; 95% CI: 0.36-0.73; P=.0002). This result was even better and more homogeneous in the analysis of symptomatic deep venous thrombosis outcome (RR: 0.43; 95% CI: 0.28-0.65; P<.0001; I2=0%; P=.49). The risk of bleeding was not significantly higher with rivaroxaban (RR: 1.20; 95% CI: 0.97-1.49; P=.09).

CONCLUSIONS

Rivaroxaban should be considerate such as a more effective alternative for thromboprophylaxis in orthopedic surgery.

The impact of adopting low-molecular-weight heparin in place of aspirin as routine thromboprophylaxis for patients with hip fracture

PURPOSE OF THE STUDY

In 2010, the National Institute for Health and Care Excellence (NICE) recommended the use of anticoagulants rather than aspirin as pharmacological thromboprophylaxis after hip fracture. We examine the impact of implementing this change in guidance on the clinical incidence of deep vein thrombosis (DVT).

STUDY DESIGN

Demographic, radiographic and clinical data were retrospectively collected for 5039 patients admitted to a single tertiary centre in the UK for hip fracture between 2007 and 2017. We calculated rates of lower-limb DVT and examined the impact of the June 2010 change of departmental policy, from use of aspirin to use of low-molecular-weight heparins (LMWH) in hip fracture patients.

RESULTS

Doppler scans were performed in 400 patients in the 180 days after a hip fracture, and identified 40 ipsilateral and 14 contralateral DVTs (p<0.001). The rate of DVT reduced significantly following the 2010 change in departmental policy from aspirin to LMWH in these patients (1.62% vs 0.83%, p<0.05).

CONCLUSIONS

The rate of clinical DVT halved following the change from aspirin to LMWH for pharmacological thromboprophylaxis, but the number needed to treat was 127. A figure of <1% for the incidence of clinical DVT in a unit that routinely uses LMWH monotherapy following hip fracture provides a context for discussions of alternative strategies, and for power calculations for future research. These figures are important to policy makers and to researchers as they will inform the design of the comparative studies on thromboprophylaxis agents for which NICE has called.

Efficacy and Safety of Rivaroxaban and Enoxaparin for Thromboprophylaxis Among Total Hip Arthroplasty Patients: A Systematic Review and Meta-Analysis

BACKGROUND

Venous thromboembolism (VTE) is one of the major and potentially life-threatening complications following major orthopedic surgeries. Research evidence comparing the effectiveness of rivaroxaban and enoxaparin for thromboprophylaxis specific to total hip arthroplasty (THA) has been limited. Hence, this review was done to compare the efficacy and safety of rivaroxaban against enoxaparin for thromboprophylaxis after THA.

MATERIALS AND METHODS

We conducted a search in databases including Medline, EMBASE, ScienceDirect, Google Scholar, and Cochrane Library from inception until May 2021. Randomized controlled trials directly comparing the effectiveness of rivaroxaban and enoxaparin for thromboprophylaxis among patients undergoing THA were eligible for inclusion. Outcome parameters assessed were efficacy in terms of total VTE and all-cause mortality, major VTE, deep vein thrombosis, symptomatic VTE, and safety in terms of major bleeding events, clinically relevant nonmajor bleeding events, minor bleeding events, total bleeding events, drug-related adverse events, and wound infection. We performed a meta-analysis with a random effects model and reported a pooled risk ratio (RR) with a 95% confidence interval (CI).

RESULTS

Eleven studies, including 9057 participants, were analyzed. Amongst efficacy outcomes, VTE and all-cause mortality pooled an RR of 0.58 (95% CI: 0.34-0.99), major VTE pooled an RR of 0.37 (95% CI: 0.15-0.90), deep vein thrombosis pooled an RR of 0.57 (95% CI: 0.32-1.02), and symptomatic VTE pooled an RR of 0.51 (95% CI: 0.30-0.87). Amongst safety outcomes, major bleeding events pooled an RR of 1.18 (95% CI: 0.77-1.80), total bleeding events pooled an RR of 1.12 (95% CI: 0.93-1.34), drug-related adverse event pooled an RR of 0.99 (95% CI: 0.87-1.12), and wound infection pooled an RR of 1.11 (95% CI: 0.58-2.14).

CONCLUSION

Rivaroxaban is a more efficacious drug in terms of VTE and all-cause mortality compared to enoxaparin following THA, and rivaroxaban was non-inferior in terms of safety profiles such as wound infection, bleeding, and drug-related adverse events.

Factor XI inhibitors: cardiovascular perspectives

Anticoagulants are the cornerstone for prevention and treatment of thrombosis but are not completely effective, and concerns about the risk of bleeding continue to limit their uptake. Animal studies and experience from patients with genetic coagulation factor XI deficiency suggesting that this factor is more important for thrombosis than for haemostasis raises the potential for drugs that target factor XI to provide safer anticoagulation. Multiple factor XI inhibitors are currently under evaluation in clinical trials, including parenterally administered antisense oligonucleotides, monoclonal antibodies, and orally active small-molecule inhibitors. Promising results of phase 2 trials in patients undergoing major orthopaedic surgery, and in those with end-stage kidney disease, atrial fibrillation and acute coronary syndromes have led to large phase 3 trials that are currently ongoing. We here review premises for the use of these agents, results so far accrued, ongoing studies, and perspectives for future patient care.

Risk of nonmajor bleeding upon use of direct oral anticoagulants for preventing and treating venous thromboembolism: A network meta-analysis

INTRODUCTION

Direct oral anticoagulants (DOACs) are associated with bleeding. Patients often stop taking DOACs due to nonmajor bleeding, which may lead to venous thromboembolism (VTE) recurrence. We aimed to determine the risk of nonmajor bleeding using different DOACs to prevent and treat VTE.

METHODS

PubMed, Embase, Web of Science, and Cochrane Library databases were searched from inception until January 6, 2021. The incidence of clinically relevant nonmajor bleeding and minor bleeding was investigated. In frequentist-based network meta-analysis, we analyzed the odds ratio (OR) with 95% CI and the surface under the cumulative ranking curves (SUCRA).

RESULTS

Twenty-seven randomized controlled trials (RCTs) (involving 64,493 patients) were included. For preventing VTE, the risk for clinically relevant nonmajor bleeding was lowest for apixaban, followed by that for low-molecular weight heparin (LMWH), dabigatran, edoxaban, and rivaroxaban. The risk for minor bleeding was lowest for apixaban, followed by that for rivaroxaban, LMWH, dabigatran, and edoxaban. For treating VTE, the risk for clinically relevant nonmajor bleeding was also lowest for apixaban, followed by that for edoxaban, vitamin K antagonists (VKAs), and rivaroxaban. The risk for minor bleeding was lowest for apixaban, followed by that for rivaroxaban and VKAs.

CONCLUSIONS

Regardless of whether it was used for preventing or treating VTE, apixaban had the lowest risk of nonmajor bleeding. This suggests that apixaban may have a lower risk of nonmajor bleeding than other anticoagulants and may help provide some clinical reference for choosing a more appropriate drug for the patient.

Thromboprophylaxis after knee arthroscopy does not decrease the risk of deep vein thrombosis: a network meta-analysis

PURPOSE

The primary aim of this network meta-analysis (NMA) is to compare the incidence of venous thromboembolisms (VTE) and bleeding risk following the use of pharmacological and non-pharmacological thromboprophylaxis for arthroscopic knee surgery (AKS). This study assumed the null hypothesis which was that there will be no difference in the incidence of VTE and bleeding risk when comparing no treatment, pharmacological treatment, and non-pharmacological treatment for preventing VTE events following AKS.

METHODS

A systematic electronic search of CENTRAL, Medline, Embase, and ClinicalTrials.gov was carried out. All English language prospective randomized clinical trials published from date of database inception to November 21, 2021 were eligible for inclusion. All papers addressing arthroscopic knee surgery were eligible for inclusion regardless of timing of surgery, operation, surgical technique, or rehabilitation. Multiple random effects NMAs were conducted to compare all treatments for each outcome. The primary outcome was the incidence of pulmonary embolism (PE) and secondary outcomes consisted of overall deep vein thrombosis (DVT), symptomatic DVT, asymptomatic DVT, and all-cause mortality. Adverse outcomes consisted of major and minor bleeding, as well as adverse events.

RESULTS

A total of nine studies with 4526 patients were included for analysis. There were 1054 patients in the no treatment/placebo group (NT/Placebo), 1646 patients in the graduated compression stockings, 810 patients in the extended-duration (> 10 days) low molecular weight heparin (Ext-LMWH) group, 650 patients in the short-duration (< 10 days) LMWH group (Short-LMWH), and 356 patients in the rivaroxaban group. GCS, Ext-LMWH, Short-LMWH and rivaroxaban all demonstrated low risks of PE, symptomatic DVT, asymptomatic DVT, combined DVT and all-cause mortality. Similarly, all interventions demonstrated a low risk of major bleeding.

CONCLUSION

There is no significant difference in the risk reduction of PEs, symptomatic DVTs, major/minor bleeding, and/or all-cause mortality when using LWMH (including short or extended regimens), rivaroxaban, graduated compression stockings or no treatment following arthroscopic knee surgery. Future primary research on the efficacy of thromboprophylaxis following arthroscopic knee surgery should stratify outcomes based on key patient (i.e., age, sex, comorbidities) and surgical (i.e., major vs. minor surgery) characteristics and should include acetylsalicylic acid as an intervention.

LEVEL OF EVIDENCE

I, network meta-analysis of Level I studies.

Enoxaparin Versus Direct Oral Anticoagulants for Venous Thromboembolism in Asians Undergoing Total Knee Arthroplasty: A Meta-Analysis and Systematic Review

BACKGROUND

The introduction of direct oral anticoagulants (DOACs) shows promise for their role as a chemoprophylaxis agent after total knee arthroplasty (TKA) for the prevention of venous thromboembolism (VTE). However, existing studies are largely based on Western populations that do not account for the different risk profiles and lower rates of VTE in Asians. This systematic review and meta-analysis aimed to evaluate the efficacy of DOACs compared with enoxaparin in an Asian-based population study.

METHODS

The review was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. All studies that compared outcomes between enoxaparin and DOACs as VTE prophylaxis after TKA in the Asian population were included.

RESULTS

Five studies with 121,153 patients were included. DOACs demonstrated a convincing benefit over enoxaparin in overall VTE prevention (odds ratio [OR] = 0.42, 95% confidence interval [CI]: 0.24-0.74). However, although the OR trended in favor of DOACs for the reduction of deep vein thrombosis events (OR = 0.54, 95% CI: 0.20-1.48) and pulmonary embolism (OR = 0.75, 95% CI: 0.07-8.20), statistical significance was not reached. In terms of bleeding complications, both arms had similar rates of major (0.91% vs 0.20%), clinically relevant nonmajor (3.28% vs 2.94%), and minor bleeding complications (12.8 vs 13.3%). A nonsignificance advantage of enoxaparin over DOACs was revealed in the OR for major bleeding (OR = 3.17; 95% CI: 0.81-12.43), whereas DOACs were favored to reduce risk of clinically relevant nonmajor (OR = 0.82; 95% CI: 0.01-91.51) and minor bleeding (OR = 0.76; 95% CI: 0.11-5.33).

CONCLUSION

DOACs confer a significantly reduced rate of overall VTE compared with enoxaparin in Asians after TKA. No significant differences in deep vein thrombosis, pulmonary embolism, and rates of bleeding complications exist.

Apixaban or enoxaparin: Which is better for thromboprophylaxis after total hip and total knee arthroplasty in Indian patients?

Both apixaban and enoxaparin are Food and Drug Administration-approved standard therapy for prophylaxis of deep-vein thrombosis; however, the superiority of one over the other is still controversial. With an objective to observe efficacy and safety outcomes of apixaban and enoxaparin in patients undergoing total hip (THA) and knee (TKA) arthroplasty, 96 patients undergoing THA/TKA (October 2018 to August 2019) were randomly allocated into 2 groups; (n = 48) apixaban; and (n = 48) enoxaparin. Efficacy outcomes and safety outcomes were recorded at 2 and 5 weeks post-TKA/THA. Follow-up functional scoring was done at 6 months postoperatively. Apixaban and enoxaparin were found to be equally efficacious in preventing venous thromboembolism; however, apixaban had a better safety profile. The apixaban group had nonsignificant higher tendency for wound discharge, atrial fibrillation and transient ischaemic attack. Enoxaparin had nonsignificant greater tendency for bleeding, wound dehiscence and pulmonary complications. Apixaban is a safe alternative to conventionally used enoxaparin for chemoprophylaxis in patients undergoing THA or TKA.

A retrospective analysis of bleeding risk with rivaroxaban, enoxaparin, and aspirin following total joint arthroplasty or revision

STUDY OBJECTIVE

Rivaroxaban, enoxaparin, and aspirin are commonly used medications for thromboprophylaxis following lower extremity joint arthroplasty or revision. Previous research has demonstrated efficacy in preventing venous thromboembolism with each medication, however, the comparative risk of bleeding between them remains poorly understood. The aim of this study was to compare the odds of bleeding between rivaroxaban, enoxaparin, and aspirin following lower extremity joint arthroplasty or revision.

DESIGN

This is a 3-year retrospective cohort study.

SETTING

Data were obtained from 148 facilities across 55 states and territories of the United States.

PATIENTS

This study included 85,938 patients who underwent hip or knee arthroplasty or revision.

INTERVENTION

Patients received enoxaparin, rivaroxaban, or aspirin as monotherapy for thromboprophylaxis.

MEASUREMENTS

The primary outcome was all bleeding, classified as major or minor bleeding, occurring in the 40 days following surgery. The secondary outcome was venous thromboembolism.

MAIN RESULTS

Among 85,938 patients, 10,465 received rivaroxaban, 14,047 received enoxaparin, and 61,426 received aspirin. Bleeding occurred in 126 (1.20%) patients with rivaroxaban, 253 (1.80%) with enoxaparin, and 611 (0.99%) with aspirin. There was a significant increase in odds of bleeding in the enoxaparin compared to aspirin group odds ratio (OR) 1.18, 95% confidence interval (CI) 1.01-1.38, p = 0.042), and a trend toward increased odds of bleeding in rivaroxaban compared to aspirin group (OR 1.21, 95% CI 0.99-1.47, p = 0.058) and rivaroxaban compared to enoxaparin (OR 1.03, 95% CI 0.82-1.28, p = 0.827). Odds of venous thromboembolism were not statistically significant between all three study medications.

CONCLUSIONS

Among rivaroxaban, enoxaparin, and aspirin used for thromboprophylaxis in knee and hip arthroplasty or revision, aspirin had significantly decreased odds of bleeding complications compared to enoxaparin. Although not statistically significant, aspirin also had a trend toward decreased odds of bleeding complications compared to rivaroxaban. Our study results suggest that aspirin is a safer alternative for use in postoperative thromboprophylaxis following lower extremity joint arthroplasty or revision.

The Evaluation of Hemostatic Abnormalities Using a CWA-Small Amount Tissue Factor Induced FIX Activation Assay in Major Orthopedic Surgery Patients

We analyzed the utility for a clot waveform analysis (CWA) of small tissue factor induced FIX activation (sTF/FIXa) assay in patients with major orthopedic surgery (including total hip arthroplasty [THA] and total knee arthroplasty [TKA]) receiving edoxaban for the prevention of venous thromboembolism (VTE). The sTF/FIXa assay using recombinant human TF in platelet-rich plasma (PRP) and platelet-poor plasma (PPP) was performed using a CWA in the above patients to monitor the efficacy of edoxaban administration. Of 147 patients (109 THA and 38 TKA), 21 exhibited deep vein thrombosis (DVT), and 15 had massive bleeding. Increased peak heights of the CWA-sTF/FIX were observed in almost patients after surgery and prolonged peak heights of the CWA-sTF/FIX were observed in almost patients treated with edoxaban. The peak heights and times of the CWA-sTF/FIX were significantly higher and shorter, respectively, in PRP than in PPP. There were no significant differences in parameters of the CWA-sTF/FIXa between the patients with and without DVT or between those with and without massive bleeding. The peak time of CWA-sTF/FIXa were significantly longer in TKA patients than in THA patients on day 1 after surgery. The second derivative peak height of the CWA-sTF/FIXa was significantly lower in TKA patients than in THA patients on day 4. The CWA-sTF/FIX reflected hemostatic abnormalities after surgery and the administration of edoxaban, and the results were better in PRP than PPP. Further studies separately analyzing the THA and TKA subgroups should be conducted.

Incidence of silent venous thromboembolism after total hip arthroplasty: A comparison of rivaroxaban and enoxaparin

PROPOSE

Total hip arthroplasty (THA) is associated with a significant risk of venous thromboembolism (VTE). Different thromboprophylaxis strategies have been used to prevent VTE. The primary aim of this study was to report the incidence of VTE and compare the efficacy and safety of rivaroxaban to enoxaparin. The secondary outcome was to report the incidence of silent deep venous thrombosis (DVT) using computed tomography venography.

METHODS

One hundred sixty patients who underwent THA were enrolled in a prospective study. Patients were randomized into two groups as follows: those who received rivaroxaban 10 mg oral daily (group RXE) and those who received enoxaparin 40 IU/day subcutaneously for 14 days (group ENO).

RESULTS

Both groups were matched for age, sex, comorbidities, special habits and preoperative laboratory investigations. The overall incidence of DVT was 5% (n = 8), which included four patients clinically diagnosed as having DVT and four with silent DVT. All the DVT cases occurred in veins below the knee and in the group RXE; none of the cases occurred in group ENO (p = 0.04). The incidence of DVT was significantly higher in patients with high body mass indexes (p < 0.001), older age (p = 0.024) and medical comorbidities (p = 0.14). No mortality, pulmonary embolism, stroke, wound infection or major bleeding occurred in either group.

CONCLUSIONS

Among the patients who underwent hip arthroplasty, rivaroxaban prophylaxis was found to be associated with lower efficacy and similar safety outcomes as compared with enoxaparin anticoagulants.

Ranking the efficacy of anticoagulants for the prevention of venous thromboembolism after total hip or knee arthroplasty: A systematic review and a network meta-analysis

BACKGROUND

Anticoagulants are essential in the prevention of venous thromboembolism. However, the effectiveness and safety of different anticoagulants have always been controversial. Therefore, we aimed to expand the sample of anticoagulant results and rank the efficacy and safety of 19 anticoagulants in the prevention of venous thromboembolism when total knee or total hip arthroplasty procedure is performed.

METHODS

A systematic review and network meta-analysis of randomized trials of adult patients undergoing total hip or knee arthroplasty were conducted. The trials were identified from PubMed, Web of Science, Cochrane Library, and Embase databases, in which anticoagulants were used as interventions randomized controlled trial. The incidence of venous embolism and bleeding are the key outcomes of assessing the efficacy of intervention drugs. We used the Physical Therapy Evidence Database (PEDro) to assess risk bias and used pairwise comparison and network meta-analysis with random effects to estimate the summary relative risk. The study has been registered with PROSPERO, number CRD42020200747.

RESULTS

From the 4083 identified manuscripts, 45,067 participants from 53 randomized trials were included in the analysis and randomly assigned to 19 anticoagulants. With Enoxaparin as a control, Rivaroxaban (risk difference 0.07, 95 % credible interval 0.06 to 0.08), Edoxaban (RD 0.09, 95 % CrI 0.08 to 0.11), and Apixaban (RD 0.05, 95 % CrI 0.04 to 0.06) had the best effect in preventing VTE. However, in terms of comprehensive bleeding rate, Apixaban, Edoxaban, and Darexaban were the most effective and stable. Although effective in preventing VTE, bleeding remains relatively high in Rivaroxaban. Enoxaparin is low-molecular-weight heparin that is widely used in clinics, and although its overall efficacy is not the best, its efficacy and safety are very stable.

CONCLUSION

According to the available data, Apixaban, Edoxaban, and Darexaban are better than any anticoagulants in the prevention of VTE and bleeding during total knee or total hip arthroplasty. In our study, Fondaparinux, Eribaxaban, Dalteparin, Betrixaban, Bemiparin, Reviparin, Acenocoumarol, and Tinzaparin were scarce in the included studies, therefore, more evidence is needed to prove their efficacy and safety.

Aspirin versus enoxaparin for the initial prevention of venous thromboembolism following elective arthroplasty of the hip or knee: A systematic review and meta-analysis

BACKGROUND

Aspirin is perceived to be non-inferior to enoxaparin, a low-molecular-weight heparin, for the prevention of venous thromboembolism (VTE) following elective arthroplasty of the hip or knee and is recommended in clinical guidelines internationally. Previous systematic reviews of aspirin as VTE prophylaxis have been limited by the inclusion of heterogenous studies where aspirin is commenced after the initial high-risk postoperative period. The purpose of this systematic review and meta-analysis was to compare the efficacy and associated harms of aspirin and enoxaparin when used as VTE prophylaxis in the initial postoperative period following elective arthroplasty of the hip or knee. We sought to: (1) to compare the use of aspirin versus enoxaparin following elective joint replacement of the hip or knee on the primary outcomes of incidence of VTE and mortality up to 3 months postoperatively and (2) assess the efficacy of aspirin with respect to secondary outcomes such as major or minor bleeding events. We hypothesised that aspirin would have equivalent efficacy for the prevention of VTE when used as initial prophylactic agent, without increasing harm from bleeding events.

PATIENTS AND METHODS

We searched Pubmed, Embase, Medline and Cochrane Central for randomized controlled trials reporting the primary outcomes of VTE incidence and mortality. Secondary outcomes included major (compromise of organ, limb or muscle function requiring unplanned re-operation) and minor bleeding events (wound ooze, minor bleed, infection). Included trials underwent a risk of bias and quality of evidence assessment using the GRADE criteria.

RESULTS

Four trials involving 1507 participants who underwent elective lower limb arthroplasty were included. We did not detect a significant difference in overall VTE rates when comparing aspirin versus enoxaparin (RR, 0.84; 95% CI: 0.41 to 1.75; p=0.65). Mortality was reported by one study and no events were recorded. There were no significant differences in the rates of all major (RR, 0.84; 95% CI: 0.08 to 9.16) or minor (RR, 0.77; 95% CI: 0.34 to 1.72) bleeding events between the aspirin and enoxaparin groups. Included trials demonstrated a significant risk of bias, and Low to Very Low quality of evidence for primary outcomes, and Moderate to Very Low for secondary outcomes.

CONCLUSION

There is currently a lack of high quality randomised controlled trials supporting the use of aspirin as VTE chemoprophylaxis in the initial postoperative period for both total hip and total knee arthroplasty. The results of this meta-analysis provide cautious endorsement for the position that aspirin is likely a safe alternative to enoxaparin for TKA patients as part of a multimodal enhanced recovery protocol, but care is advised for THA patients owing to a lack of data from trials. Current evidence from randomized controlled trials is generally of low quality, and does not estimate critical event data for VTE incidence or mortality, as well as major and minor bleeding events with sufficient certainty. PROSPERO Registration CRD42018110784.

LEVEL OF EVIDENCE

II, systematic review.

Thromboprophylaxis for orthopedic surgery; An updated meta-analysis

BACKGROUND

Venous thromboembolism (VTE) is a serious complication of orthopedic surgery. Low molecular weight heparin (LMWH) has been the standard of care for thromboprophylaxis in this population. However, direct oral anticoagulants (DOACs) are increasingly being used as alternatives.

OBJECTIVE

To assess the efficacy and safety of DOACs versus LMWH for thromboprophylaxis in orthopedic surgery.

METHODS

We searched MEDLINE, Embase, and the Cochrane Collaboration Central Register of Controlled Trials from inception until April 2020, for randomized controlled trials (RCTs) comparing DOACs with LMWH for thromboprophylaxis in orthopedic surgery.

RESULTS

Twenty-five RCTs met inclusion criteria, including 40,438 patients, with a mean age of 68 years and 50% were males. Compared to LMWH, DOACs were associated with a significant reduction of major VTE; defined as the composite events of proximal deep vein thrombosis (DVT), pulmonary embolism (PE), and VTE-related mortality (RR 0.33; 95% CI: 0.20-0.53; P<0.01), and total DVT (RR: 0.59; 95% CI: 0.48-0.73; P<0.01), but not PE (RR 0.81; 95% CI: 0.49-1.34; P=0.42). There was no statistically significant difference between both groups on the incidence of major bleeding (RR 0.99; 95% CI: 0.77-1.27; P=0.92), clinically relevant non-major bleeding (RR 1.04; 95% CI: 0.92-1.17; P=0.52), all-cause mortality (RR 1.06; 95% CI: 0.64-1.76; P=0.83), VTE-related mortality (RR 0.84; 95% CI: 0.40-1.74; P=0.64) and bleeding-related mortality (RR 1.24; 95% CI: 0.30-5.18; P=0.77).

CONCLUSION

For patients undergoing orthopedic surgery, thromboprophylaxis with DOACs is associated with a significant reduction of major VTE and DVT, compared to LMWH. Safety outcomes were not significantly different between both treatment groups.

NONSPECIFIC DYSPLASIA OF THE CONNECTIVE TISSUE – A FACTOR OF VENOUS THROMBOEMBOLIC COMPLICATIONS IN ENDOPROSTHETICS OF HIP JOINTS

Background. Important part of orthopedic surgery is endoprosthetics of hip joints, which eliminates pain syndrome, restores the amplitude of movement and the support ability of lower limbs. But some complications usually take place; venous thromboembolism is leading among them. Objective. The aim of the study was to investigate endothelial dysfunction and activity of the hemocoagulation system at different levels of VTEC risks and thus to work out the strategy of thromboprophylaxis in patients with osteoarthrosis of the hip joint and femoral neck fracture combined with non-specific dysplasia of the connective tissue. Methods. 219 patients of a mean age of 64.7±3.8 years old underwent surgery. In 137 (62.1%) cases, a total cement hip replacement was performed for osteoarthritis. 82 (37.4%) patients underwent total and unipolar cement hip replacement for cervical femoral neck fractures. Results. Clinical manifestations of non-specific connective tissue dysplasia were detected in 83 (37.9%) patients that was confirmed by the laboratory determination of the level of general, bound and free oxyproline. In the postoperative period, the thrombotic process in the venous system of the inferior vena cava was diagnosed in 23 (10.5%) cases. The level of indicators of endothelium status dysfunction was much more significant in the patients in cases of nonspecific dysplasia of connective tissue. Operative intervention on the hip joint in the patients with nonspecific dysplasia of connective tissue in 11 (13.3%) cases was complicated by development of venous thrombosis. In the patients without non-specific connective tissue dysplasia, postoperative thrombosis in the system of the inferior vena cava was diagnosed in 12 (8.8%) cases. Conclusions. Patients with osteoarthrosis of the hip joint and the femoral neck fracture accompanied by the non-specific dysplasia of the connective tissue are characterized by high levels of endothelial dysfunction and increased activity of the blood-coagulation system.

Factors Affecting the Formation and Treatment of Thrombosis by Natural and Synthetic Compounds

Venous thromboembolism (VTE) refers to deep vein thrombosis (DVT), whose consequence may be a pulmonary embolism (PE). Thrombosis is associated with significant morbidity and mortality and is the third most common cardiovascular disease after myocardial infarction and stroke. DVT is associated with the formation of a blood clot in a deep vein in the body. Thrombosis promotes slowed blood flow, hypoxia, cell activation, and the associated release of many active substances involved in blood clot formation. All thrombi which adhere to endothelium consist of fibrin, platelets, and trapped red and white blood cells. In this review, we summarise the impact of various factors affecting haemostatic disorders leading to blood clot formation. The paper discusses the causes of thrombosis, the mechanism of blood clot formation, and factors such as hypoxia, the involvement of endothelial cells (ECs), and the activation of platelets and neutrophils along with the effects of bacteria and reactive oxygen species (ROS). Mechanisms related to the action of anticoagulants affecting coagulation factors including antiplatelet drugs have also been discussed. However, many aspects related to the pathogenesis of thrombosis still need to be clarified. A review of the drugs used to treat and prevent thrombosis and natural anticoagulants that occur in the plant world and are traditionally used in Far Eastern medicine has also been carried out.

Venous thromboprophylaxis after total hip arthroplasty: aspirin, warfarin, enoxaparin, or factor Xa inhibitors?

INTRODUCTION

Debate over the ideal agent for venous thromboembolism (VTE) prophylaxis after total hip arthroplasty (THA) has led to changes in prescribing trends of commonly used agents. We investigate variation in utilisation and the differences in VTE incidence and bleeding risk in primary THA after administration of aspirin, warfarin, enoxaparin, or factor Xa inhibitors.

METHODS

8829 patients were age/sex matched from a large database of primary THAs performed between 2007 and 2016. Utilisation was calculated using compound annual growth rate. Incidence of postoperative deep venous thrombosis (DVT), pulmonary embolism (PE), bleeding-related complications, postoperative anaemia, and transfusion were identified at 2 weeks, 30 days, 6 weeks, and 90 days.

RESULTS

Aspirin use increased by 33%, enoxaparin by 7%, and factor Xa inhibitors by 31%. Warfarin use decreased by 1%. Factor Xa inhibitors (1.7%) and aspirin (1.7%) had the lowest incidence of DVT followed by enoxaparin (2.6%), and warfarin (3.7%) at 90 days. Factor Xa inhibitors (12%) and aspirin (12%) had the lowest incidence of blood transfusion followed by warfarin (15%) and enoxaparin (17%) at 90 days. There was no difference in incidence of blood transfusion or bleeding-related complications nor any detectable difference in symptomatic PE incidence.

CONCLUSIONS

The utilisation of aspirin and factor Xa inhibitors increased over time. Aspirin and factor Xa inhibitors provided improved DVT prophylaxis with lower rates of postoperative anaemia compared to enoxaparin and warfarin.

Implant positioning among the surgical approaches for total hip arthroplasty: a Bayesian network meta-analysis

INTRODUCTION

Although there is anatomical individuality among patients, some standardized requirements for component orientation for total hip arthroplasty (THA) exist. To date, no study has compared implant positioning using a network meta-analysis (NMA). Hence, the purpose of this study was to perform a NMA comparing implant positioning among the various approaches for THA.

METHODS

This study was conducted according to the PRISMA extension statement for reporting of systematic reviews incorporating network meta-analyses of health care interventions. All randomized (RCT) and non-randomized (nRCT) clinical trials comparing two or more different approaches for THA were considered for inclusion. For the statistical analysis, the STATA Software/ MP, Version 14.1 (Stata Corporation, College Station, Texas, USA) was used. The NMA was performed through a Stata routine for Bayesian hierarchical random-effects model analysis.

RESULTS

We enrolled in the present study, a total of 4060 patients, with a mean of 17.84 ± 16.41 months follow-up. The patient baseline data were very homogeneous across the groups concerning age (P = 0.91), sex (P = 0.52), and BMI (P = 0.83). Concerning the cup anteversion, the anterolateral approach reported the value closest to the reference value. The test for overall inconsistency, however, was not statistically significant (P = 0.30). Concerning cup inclination, the lateral approach reported the value closest to the reference value. The test for overall inconsistency was statistically significant (P = 0.01).

CONCLUSION

The anterolateral approach for total hip arthroplasty detected the best femoral stem alignment and cup anteversion. Data concerning cup inclination detected no sufficient transitivity to draw consistent conclusions.

Comparison of the Efficacy and Safety of Aspirin and Rivaroxaban Following Enoxaparin Treatment for Prevention of Venous Thromboembolism after Hip Fracture Surgery

OBJECTIVE

To compare the efficacy and safety of aspirin with rivaroxaban following treatment with enoxaparin for prevention of venous thromboembolism (VTE) after hip fracture surgery (HFS).

METHODS

A total of 390 patients were enrolled in the trial. According to an odd or even number at the end of their registration number, the patients were divided into the aspirin group (n = 198) and the rivaroxaban group (n = 192). All patients were given enoxaparin subcutaneous injection after the operation and returned to the routine dose the next day until postoperative day five. The patients in the aspirin group received an additional 16 days of thromboprophylaxis with 100 mg of aspirin once daily. The rivaroxaban group was assigned to receive an additional 16 days of thromboprophylaxis with 10 mg of oral rivaroxaban once daily. Patients were followed for 90 days regarding VTE and bleeding complications.

RESULTS

The incidence of VTE in the aspirin group and rivaroxaban group was 6.6% (13/198) and 5.7% (11/192), respectively (P = 0.83). The rate of major bleeding events occurred in two (1.0%) patients in the aspirin group and in one patient (0.5%) in the rivaroxaban group (P = 1.0). A combination of major bleeding and clinically relevant nonmajor bleeding occurred in five patients (2.5%) in the aspirin group and in six patients (3.1%) in the rivaroxaban group (P = 0.77). During the 90-day follow-up, a pulmonary embolism developed in one patient (0.5%) in the aspirin group and none in the rivaroxaban group (P = 1.0).

CONCLUSIONS

Extended prophylaxis for 21 days with aspirin was equivalent to the direct oral anticoagulant rivaroxaban after hip fracture surgery with an initial 5-day postoperative course of enoxaparin. Aspirin may be an effective, safe, convenient, and cheap alternative for extended prophylaxis after hip fracture surgery.

Atrial fibrillation in patients with end-stage renal disease on hemodialysis: Magnitude of the problem and new approach to oral anticoagulation

Atrial fibrillation (AF) is a frequent comorbid condition in patients with end-stage renal disease on hemodialysis (HD) with a prevalence of up to 27%. The incidence rate of stroke in AF patients on HD is approximately 5%. The AF-associated risk of stroke is a major clinical challenge because current evidence for anticoagulation in HD patients with AF is based on observational data. Results from these observational studies is largely contradictory because they do not show a clear benefit of vitamin K antagonists over no treatment in terms of stroke prevention, and they show an increased risk of hemorrhage associated with anticoagulation treatment in HD patients. HD patients were not included in randomized trials of the direct oral anticoagulants (DOACs), and therefore there is no evidence to support efficacy and safety of DOACs compared to vitamin K antagonists in HD patients. The pharmacological characteristics of DOACs are of particular interest in the HD setting. The factor Xa inhibitors rivaroxaban, apixaban, and edoxaban are not predominantly eliminated via the kidneys. The thrombin inhibitor dabigatran is 80% eliminated via the kidneys but is dialyzable due to its low protein binding. In this narrative review, we examine the current state of evidence regarding the prevalence of AF in patients on HD, the associated risk of stroke, and the efficacy and safety of anticoagulation for stroke prevention in the HD setting. Further, based on the pharmacokinetic properties of DOACs, we discuss their potential use in patients on HD and ongoing randomized trials.

Factor Xa Inhibitors and Direct Thrombin Inhibitors Versus Low-Molecular-Weight Heparin for Thromboprophylaxis After Total Hip or Total Knee Arthroplasty: A Systematic Review and Meta-Analysis

BACKGROUND

The purpose of this study is to perform a meta-analysis to compare outcomes of venous thromboembolism (VTE) prophylaxis with low-molecular-weight heparin (LMWH) vs other anticoagulants in patients who received total knee (TKA) or total hip arthroplasty (THA).

METHODS

MEDLINE, Cochrane, EMBASE, and Google Scholar databases were searched until June 30, 2017 for eligible randomized controlled studies.

RESULTS

Thirty-two randomized controlled studies were included. LMWH provided better protection against VTE than placebo. In both TKA and THA patients, the rates of VTE were lower with factor Xa inhibitors than LMWH. In THA patients, the rate of deep vein thrombosis (DVT) was lower with factor Xa inhibitors than LMWH. In TKA patients, the rates of VTE and DVT were similar between LMWH and direct thrombin inhibitors. In THA patients, the rate of VTE was lower with direct thrombin inhibitors than with LMWH, while the DVT rates were similar. The pulmonary embolism rates were similar between all 3 classes of drugs in TKA and THR patients, as were the major bleeding rates. Nonmajor and minor bleeding rates were also similar between the 3 drug classes.

CONCLUSION

LMWH is associated with a higher rate of VTE than factor Xa inhibitors in TKA and THA patients. Direct thrombin inhibitors are associated with a lower rate of VTE in THA patients, but their effectiveness with respect to DVT and pulmonary embolism prophylaxis is similar to that of LMWH in TKA and THA patients.

Effectiveness and safety of rivaroxaban for the prevention of thrombosis following total hip or knee replacement: A systematic review and meta-analysis

BACKGROUND

Prophylactic anticoagulant therapy is recommended to reduce the risk of venous thromboembolism (VTE) after total hip or knee arthroplasty, and has become the standard of care. Rivaroxaban is a novel oral medication that directly inhibits factor Xa for the prevention and treatment of thromboembolic conditions.

METHOD

A meta-analysis of randomized controlled trials (RCTs) was performed to determine the efficacy and safety of rivaroxaban after total hip arthroplasty (THA) and total knee arthroplasty (TKA) surgery. We reviewed several databases including PubMed, the Cochrane Library, Embase and the US trial registry to detect appropriate RCTs for our meta-analysis. The primary efficacy outcome of this meta-analysis was the combination of any deep-vein thrombosis (DVT), non-fatal pulmonary embolism (PE), and death from any cause. The main safety outcome was bleeding events which included significant bleeding events, clinically relevant insignificant bleeding events, or minor events. Other end points were the number of patients who received blood transfusion the volume of transfused whole blood or red blood cells, and the volume of postoperative drainage.

RESULT

Thirteen RCTs were included in this meta-analysis. This meta-analysis showed that the overall rate of VTE events, DVT, PE, and death were 1%, 6%, < 1% and < 1%, respectively, for patients receiving treatment with rivaroxaban after THA and TKA surgery. The subgroup analysis demonstrated rivaroxaban had more superior effects in THA patients. The pooled analysis of bleeding events showed that the overall rate of major bleeding events, overt bleeding events associated with fall in Hb of > 2 g/DL, clinically overt bleeding events leading to transfusion of > 2 units of blood, clinically overt bleeding events leading to further surgeries, and non-major bleeding events were < 1%, < 1%, < 1%, < 1%, and 3%, respectively.

CONCLUSION

This is the first systematic review of the literature providing incidence of efficacy and safety outcomes for thromboprophylaxis in THA and TKA patients. Moreover, this meta-analysis showed that rivaroxaban had more superior effect in THA patients.

Comparison of pharmacologic prophylaxis in prevention of venous thromboembolism following total knee arthroplasty

BACKGROUND

Anticoagulants are used following total knee arthroplasty (TKA) to prevent venous thromboembolism (VTE). These drugs reduce VTE risk but may lead to bleeding-related complications. Recently, surgeons have advocated using antiplatelet agents including aspirin (ASA). However, there is no consensus regarding which medication has the optimal risk/benefit profile. The purpose of this study was to compare rates of VTE using different anticoagulants in anticoagulation-naïve patients being discharged home after TKA.

METHODS

A national private insurance database was used to identify patients undergoing unilateral TKA. Patients with a prior history of VTE were excluded. Anticoagulants included ASA, low molecular weight heparin (LMWH), warfarin, factor Xa inhibitors (XaI), and fondaparinux. Postoperative complications, including VTE, blood transfusion, myocardial infarction, and hematoma, were identified using ICD-9 diagnosis codes. Risk of each complication was compared between groups using multivariate logistic regression controlling for demographics, length of stay, and comorbidities.

RESULTS

Of 30,813 patients, 1.82% were diagnosed with VTE. Using ASA as a baseline, there was significantly decreased risk of VTE with LMWH (OR 0.47), XaI (OR 0.50), and fondaparinux (OR 0.32). There was significantly higher risk of transfusion with LMWH (OR 1.56) and fondaparinux (OR 1.84), but no difference in hematoma between medications.

CONCLUSIONS

This study shows that there is a decreased risk of VTE with LMWH, XaI, and fondaparinux compared to ASA. However, these medications also had higher rates of bleeding-associated complications. The choice of pharmacologic prophylaxis should be made based on a balance of the risk/benefit profile of each medication.

LEVEL OF EVIDENCE

III.

Rivaroxaban versus enoxaparin for the prevention of venous thromboembolism after total knee arthroplasty: A meta-analysis

OBJECTIVE

This article analyzed the clinical efficacy and tolerability of rivaroxaban and enoxaparin in patients undergoing total knee arthroplasty (TKA) surgery.

METHODS

Five randomized, controlled clinical trials on rivaroxaban versus enoxaparin in patients who underwent TKA were identified and included in this meta-analysis.

RESULTS

The meta-analysis indicated that rivaroxaban prophylaxis was associated with lower rates of symptomatic venous thromboembolism (VTE) (relative risk[RR]:0.55; 95% confidence interval [CI]: 0.35-0.86; P = .009), symptomatic deep vein thrombosis (DVT) (RR 0.44, 95% CI 0.25-0.80, P = .007), asymptomatic DVT (RR: 0.57; 95% CI: 0.37-0.89; P = .01), distal DVT (RR: 0.62; 95% CI: 0.45-0.85; P = .003) and proximal DVT (RR: 0.42; 95% CI: 0.24-0.75; P = .004). Compared with the enoxaparin group, the incidence of symptomatic pulmonary embolism (PE) (RR: 0.48; 95% CI: 0.19-1.24; P = .13) in the rivaroxaban group was not significantly different. A nonsignificant trend towards all-cause death (RR: 0.38; 95% CI: 0.03-4.92; P = .46) or major bleeding (RR: 1.59; 95% CI: 0.77-3.27; P = .21) risk between rivaroxaban and enoxaparin prophylaxis was found.

CONCLUSION

Compared with the enoxaparin group, the group using rivaroxaban after TKA had a significantly lower rate of symptomatic VTE, symptomatic DVT, asymptomatic DVT, distal DVT, and proximal DVT. Our study shows that rivaroxaban after TKA is more effective than enoxaparin and did not increase major bleeding or all-cause mortality.

Similar thromboprophylaxis with rivaroxaban and low molecular weight heparin but fewer hemorrhagic complications with combined intra-articular and intravenous tranexamic acid in total knee arthroplasty

PURPOSE

To evaluate the efficacy of the combined intravenous and intra-articular administration of tranexamic acid (TXA) to control the collateral effects and complications of rivaroxaban (RIV) after total knee arthroplasty (TKA) and to compare thromboprophylaxis schemes with and without TXA, RIV and low molecular weight heparin (LMWH).

MATERIALS AND METHODS

We prospectively studied 158 TKA patients from 2014 to 2018. The patients were randomly assigned into three groups. Group A (46 patients) was administered intravenous and intra-articular TXA and RIV postoperatively; group B (58 patients) was administered TXA as in group A and LMWH postoperatively; and group C (54 patients) was administered saline as in group A and RIV postoperatively. We evaluated blood loss, transfusion requirements and hemorrhagic complications.

RESULTS

Hct and Hb values significantly decreased in group C compared to groups A and B, without any difference between groups A and B. Suction drain blood volume output was significantly higher in group C compared to group A and B, without any difference between group A and B. Hemorrhagic complications were more common in group C. No patient experienced clinical findings of VTE.

CONCLUSION

Combined intravenous and intra-articular administration of TXA is safe and effective in TKA, with fewer hemorrhagic complications compared to placebo. Thromboprophylaxis with RIV and LMWH is similar.

Low molecular weight heparin versus other anti-thrombotic agents for prevention of venous thromboembolic events after total hip or total knee replacement surgery: a systematic review and meta-analysis

Background

Venous thromboembolism (VTE) is an important complication following total hip replacement (THR) and total knee replacement (TKR) surgeries. Aim of this study was to comprehensively compare the clinical outcomes of low-molecular-weight heparin (LMWH) with other anticoagulants in patients who underwent TKR or THR surgery.

Methods

Medline, Cochrane, EMBASE, and Google Scholar databases were searched for eligible randomized controlled studies (RCTs) published before June 30, 2017. Meta-analyses of odds ratios were performed along with subgroup and sensitivity analyses.

Results

Twenty-one RCTs were included. In comparison with placebo, LMWH treatment was associated with a lower risk of VTE and deep vein thrombosis (DVT) (P values < 0.001) but similar risk of pulmonary embolism (PE) (P = 0.227) in THR subjects. Compared to factor Xa inhibitors, LMWH treatment was associated with higher risk of VTE in TKR subjects (P < 0.001), and higher DVT risk (P < 0.001) but similar risk of PE and major bleeding in both THR and TKR. The risk of either VTE, DVT, PE, or major bleeding was similar between LMWH and direct thrombin inhibitors in both THR and TKR, but major bleeding was lower with LMWH in patients who underwent THR (P = 0.048).

Conclusion

In comparison with factor Xa inhibitors, LMWH may have higher risk of VTE and DVT, whereas compared to direct thrombin inhibitors, LMWH may have lower risk of major bleeding after THR or TKR.

Electronic supplementary material

The online version of this article (10.1186/s12891-018-2215-3) contains supplementary material, which is available to authorized users.

Outcome of Direct Oral Anticoagulant Treatment for Acute Lower Limb Deep Venous Thrombosis After Total Knee Arthroplasty Or Total Hip Arthroplasty

Objective: The aim of this study was to examine the treatment outcomes of edoxaban and apixaban on deep venous thrombosis (DVT) in Japanese patients undergoing total knee arthroplasty (TKA) or total hip arthroplasty (THA). Methods: We examined 100 patients receiving edoxaban or apixaban to treat lower limb DVT. The primary efficacy outcome was defined as the disappearance of DVT at three months post-treatment. The primary safety outcome was the change in hemoglobin (Hb) value after two and seven days of treatment compared with baseline, which was the start of treatment with edoxaban or apixaban. Results: The primary efficacy outcome occurred in 61 of the 70 patients (87.1%) in the edoxaban group and in 28 of the 30 patients (93.3%) in the apixaban group. There was no significant difference between the edoxaban and apixaban groups in the disappearance of DVT at three months (p = .497). The change in Hb value from baseline to two days post-treatment was -0.53 ± 0.98 in the edoxaban group and -0.06 ± 0.75 in the apixaban group (p = .010). At seven days post-treatment, the changes in Hb were -0.03 ± 1.60 and 0.30 ± 0.68 (p = .007) in the edoxaban and apixaban groups, respectively. Conclusion: Edoxaban and apixaban were equivalent in efficacy. However, apixaban was superior to edoxaban in terms of the change in Hb value. In cases of major bleeding, both edoxaban and apixaban need to be used carefully when treating DVT.

Thromboprophylaxis with enoxaparin and direct oral anticoagulants in major orthopedic surgery and acutely ill medical patients: a meta-analysis

Subjects undergoing major orthopedic surgery and acutely ill hospitalized medical patients represent a population at medium-high risk for venous thromboembolism (VTE). They are treated with low molecular weight heparin (LMWH) and direct oral anticoagulants [DOACs] for VTE prevention. We conducted a meta-analysis of phase III randomized clinical trials evaluating LMWH enoxaparin versus DOACs for prophylaxis of VTE by combining studies including patients undergoing elective total hip and knee replacement surgery, and acutely ill hospitalized medical subjects. Studies were searched using PubMed, MEDLINE, and EMBASE databases until December 2016. Differences in clinical outcomes for efficacy and safety endpoints between treatment groups were expressed as risk differences with 95% confidence intervals (95% CI), using random effects regression models. Fourteen RCTs were considered (60,467 subjects). Overall mortality, symptomatic deep venous thrombosis, non-fatal pulmonary embolism (PE) major bleeding (MB) and clinically relevant non-major bleeding (CRNMB) are not different between treatment regimens. Treatment with LMWH enoxaparin is associated with a lower risk of fatal PE plus VTE-related death compared therapy with DOACs (RD = 0.040%, 95% CI 0.001-0.080%, p = 0.0434). Subgroup analysis shows an incidence of MB (RD = 0.181%, 95% CI 0.029-0.332%, p = 0.0033) and CRNMB (RD = 0.546%, 95% CI 0.009-1.082%, p = 0.0462) in patients treated with 40 mg OD enoxaparin compared to DOACs. In major orthopedic surgery and acutely ill hospitalized medical patients, DOACs do not offer clear advantages in terms of clinical efficacy compared to enoxaparin. The advantage of the latter in terms of major and CRNMB, when used at a dose of 40 mg, is statistically significant, but small in terms of clinical relevance.

Formulary Drug Review: Betrixaban

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Comparison of three different anti-Xa assays in major orthopedic surgery patients treated with direct oral anticoagulant

Background

Measurement of edoxaban plasma concentration has been gathering attention in major orthopedic surgery patients receiving edoxaban for the prevention of venous thromboembolism (VTE).

Methods

The anti-Xa activity was measured one hour after edoxaban intake using 3 different assays in 200 patients after major orthopedic surgery.

Results

The anti-Xa activities on Day 8 were significantly higher than those on Day 4 and those on Day 4 were significantly higher than those on Day 1. The anti-Xa activities in two assays closely correlated with each other, but the other anti-Xa assay did not correlated with other two assays. The anti-Xa activities as detected in the three Xa assays were significantly higher in the patients without deep vein thrombosis (DVT) than in those with DVT on Day 4. Additionally, there were no significant differences in the anti-Xa activities of assays A, B and C between patients with and without massive bleeding (MB) on Days 1, 4, 8 and 15.

Conclusion

The results of this study suggest that anti-Xa level could be predictive of the risk of VTE, but not of the risk of massive bleeding.

Monitoring of hemostatic abnormalities in major orthopedic surgery patients treated with edoxaban by APTT waveform

INTRODUCTION

An analysis of the activated partial thromboplastin time (APTT) in major orthopedic surgery patients receiving edoxaban for the prevention of venous thromboembolism (VTE) was carried out.

METHODS

The APTT waveform was analyzed in the above patients to monitor edoxaban administration.

RESULTS

Of these 99 patients, 12 exhibited deep vein thrombosis, and 25 had massive bleeding. An increased biphasic pattern of the APTT waveform was observed after the administration of edoxaban, but there were no significant differences between the patients with and without complications. The peak times of acceleration, velocity, and 1/2 fibrin formation were significantly prolonged after the administration of edoxaban, especially in patients with massive bleeding, and were moderately correlated with the anti-Xa activity. While the heights of velocity and acceleration peak 2 were lower in patients receiving warfarin treatment than in those receiving edoxaban, the widths of these parameters were significantly longer. The height of 1/2 fibrin formation and the width of acceleration peaks 1 and 2 and the velocity were significantly increased after the administration of edoxaban.

CONCLUSION

The peak time of the APTT waveform was significantly prolonged after the administration of edoxaban. The analysis of the APTT waveform may therefore be useful for the prediction of the risk of massive bleeding.

Venous Thromboembolism Prophylaxis After TKA: Aspirin, Warfarin, Enoxaparin, or Factor Xa Inhibitors?

BACKGROUND

There is considerable debate regarding the ideal agent for venous thromboembolism (VTE) prophylaxis after TKA. Numerous studies and meta-analyses have yet to provide a clear answer and often omit one or more of the commonly used agents such as aspirin, warfarin, enoxaparin, and factor Xa inhibitors.

QUESTIONS/PURPOSES

Using a large database analysis, we asked: (1) What are the differences in VTE incidence in primary TKA after administration of aspirin, warfarin, enoxaparin, or factor Xa inhibitors? (2) What are the differences in bleeding risk among these four agents? (3) How has use of these agents changed with time?

METHODS

We queried a combined Humana and Medicare database between 2007 and Quarter 1 of 2016, and identified all primary TKAs performed using ICD-9 and Current Procedural Terminology codes. All patients who had any form of antiplatelet or anticoagulation prescribed within 1 year before TKA were excluded from our study cohort. We then identified patients who had either aspirin, warfarin, enoxaparin, or factor Xa inhibitors prescribed within 2 weeks of primary TKA. Each cohort was matched by age and sex. Elixhauser comorbidities and Charlson Comorbidity Index for each group were calculated. We identified 1016 patients with aspirin, and age- and sex-matched 6096 patients with enoxaparin, 6096 patients with warfarin, and 5080 patients with factor Xa inhibitors. Using ICD-9 codes, with the understanding that patients at greater risk may have had more-attentive surveillance, the incidence of postoperative deep venous thrombosis (DVT), pulmonary embolism (PE), bleeding-related complications (bleeding requiring surgical intervention, hemorrhage, hematoma, hemarthrosis), postoperative anemia, and transfusion were identified at 2 weeks, 30 days, 6 weeks, and 90 days postoperatively. A four-way chi-squared test was used to determine statistical significance. Utilization was calculated using compound annual growth rate.

RESULTS

There was a difference in the incidence of DVT at 90 days (p < 0.01). Factor Xa inhibitors (2.9%) had the lowest incidence of DVT followed by aspirin (3.0%) and enoxaparin (3.5%), and warfarin (4.8%). There was a difference in the incidence of PE at 90 days (p < 0.01). Factor Xa inhibitors (0.9%) had the lowest incidence of PE followed by enoxaparin (1.1%), aspirin (1.2%), and warfarin (1.6%). There was a difference in the incidence of postoperative anemia at 90 days (p < 0.01). Aspirin (19%) had the lowest incidence of postoperative anemia followed by warfarin (22%), enoxaparin (23%), and factor Xa inhibitors (23%). There was a difference in the incidence of a blood transfusion at 90 days (p < 0.01). Aspirin (7%) had the lowest incidence of a blood transfusion followed by factor Xa inhibitors (9%), warfarin (12%), and enoxaparin (13%). There were no differences in bleeding-related complications (p = 0.81) between the groups. Aspirin use increased at a compound annual growth rate of 30%, enoxaparin at 3%, and factor Xa inhibitors at 43%, while warfarin use decreased at a compound annual growth rate of -3%.

CONCLUSIONS

Factor Xa inhibitors had the highest growth in utilization during our study period, followed by aspirin, when compared with enoxaparin and warfarin. When selected for the right patient, factor Xa inhibitors provided improved VTE prophylaxis compared with enoxaparin and warfarin, with a lower rate of blood transfusion. Aspirin provided comparable VTE prophylaxis compared with factor Xa inhibitors with improved VTE prophylaxis compared with enoxaparin and warfarin with the lowest risk of bleeding.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Low-Molecular-Weight Heparin and the Relative Risk of Surgical Site Bleeding Complications: Results of a Systematic Review and Meta-Analysis of Randomized Controlled Trials of Venous Thromboprophylaxis in Patients After Total Joint Arthroplasty

BACKGROUND

Venous thromboembolism causes significant morbidity and mortality in patients after total joint arthroplasty. Although network meta-analyses have demonstrated a benefit of various thromboprophylactic agents, there remains a concern in the surgical community regarding the resulting wound complications. There is currently no systematic review of the surgical site bleeding complications of thromboprophylactic agents. The aim of this study was to systematically review the surgical site bleeding outcomes of venous thromboembolism prophylaxis in this population.

METHODS

A systematic review and meta-analysis was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Randomized controlled trials comparing more than one of low-molecular-weight heparin (LMWH), warfarin, rivaroxaban, apixaban, dabigatran, aspirin, or no pharmacologic treatment in patients after total hip or knee arthroplasty were selected for inclusion. Five meta-analyses were performed to compare LMWH with control, warfarin, apixaban, rivaroxaban, and dabigatran.

RESULTS

Forty-five randomized controlled trials of 56,730 patients were included. LMWH had a significantly increased relative risk of surgical site bleeding in comparison with control (relative risk, 2.32; 95% confidence interval, 1.40-3.85) and warfarin (1.54; 1.23-1.94). The relative risk of LMWH trended higher than apixaban (1.27; 1.00-1.63) and was similar to rivaroxaban (0.95; 0.74-1.23). Only 1 study reported the risk of surgical site bleeding in LMWH vs dabigatran (5.97; 2.08-17.11).

CONCLUSION

LMWH increased the risk of surgical site bleeding compared with control, warfarin. and dabigatran and trended toward an increased risk compared with apixaban. The risk of surgical site bleeding was similar with LMWH and rivaroxaban.

A comparison of apixaban and dabigatran etexilate for thromboprophylaxis following hip and knee replacement surgery

INTRODUCTION

Patients who have undergone hip or knee replacement surgery are exposed to a high risk of developing a post-operative venous thromboembolus and so have a need for an effective, medication-based, thrombosis prophylaxis. New orally active anticoagulants have been available for a few years now. These specific substances directly block either thrombin (e.g., dabigatran etexilate) or Factor Xa (e.g., apixaban). It is not clear whether there are any efficacy differences between these two substances because there have never been any head-to-head studies carried out.

MATERIALS AND METHODS

We have carried out a study comparing two new orally active anticoagulants dabigatran etexilate (Pradaxa^®) and apixaban (Eliquis^®) that were each given to two groups of 200 patients respectively, who had undergone elective hip or knee arthroplasty (100 each). Each patient was assessed for pre- and post-operative hemoglobin concentrations, post-operative blood loss, the number of transfused erythrocyte concentrates, the duration of wound secretion, clinical thromboembolic complications (deep vein thrombosis, pulmonary embolism, myocardial infarct), as well as gastrointestinal, intracranial or wound-related bleeding complications.

RESULTS

Dabigatran etexilate treatment led to a significant increase in the duration of wound secretion in both arthroplasty groups when compared to apixaban: wound secretion lasted 1.2 days longer on average in the dabigatran etexilate group than in the apixaban group (4.1 ± 2.1 vs. 2.9 ± 1.8 days). There were no significant differences observed between the two anticoagulant groups when comparing pre- and post-operative Hb values, post-operative blood loss and the other clinical parameters.

CONCLUSIONS

Thus, it appears that the direct thrombin inhibitor, dabigatran etexilate, is associated with a longer period of wound secretion following the implantation of hip and knee endoprostheses than that associated with the Factor Xa inhibitor, apixaban.

Direct Oral Anticoagulants Vs. Enoxaparin for Prevention of Venous Thromboembolism Following Orthopedic Surgery: A Dose-Response Meta-analysis

We carried out a dose–response model‐based meta‐analysis to assess venous thromboembolism (VTE) and bleeding with factor Xa (FXa) inhibitors (apixaban, edoxaban, rivaroxaban) and a thrombin inhibitor (dabigatran) compared with European (EU) (40 mg q.d.) and North American (NA) (30 mg Q12H) dose regimens of a low molecular weight heparin (enoxaparin) following orthopedic surgery. Statistically significant differences in both VTE and bleeding outcomes were found between the NA and EU doses of enoxaparin, with odds ratios (95% confidence interval) for the NA vs. EU dose of 0.73 (0.71–0.76) and 1.20 (1.14–1.29) for total VTE and major bleeding, respectively. At approved doses, estimated odds ratios vs. both doses of enoxaparin for the three FXa inhibitors (range: 0.35–0.75 for VTE; 0.76–1.09 for bleeding) compared with those for dabigatran (range: 0.66–1.21 for VTE; 1.10–1.38 for bleeding) suggested generally greater efficacy and less bleeding for the FXa inhibitors.

Patient compliance with new oral anticoagulants after major orthopaedic surgery: rivaroxaban and dabigatran compared with subcutaneous injection of fondaparinux

PURPOSE

the main purpose of our study was to compare patient compliance with the orally administered new oral anticoagulants (NOCs) dabigatran and rivaroxaban compared with subcutaneously injected fondaparinux after major orthopaedic surgery, and to assess patient preference for the oral vs subcutaneous administration route.

METHODS

prophylactic antithrombotic drug therapy with dabigatran (group D; GD, n=32 patients), rivaroxaban (group R; GR, n=38 patients) or fondaparinux (group F; GF, n=30 patients), to prevent deep vein thrombosis, was started immediately after surgery in 100 patients submitted to total hip arthroplasty.

RESULTS

the patients had a mean age of 68.7±11 years and 62% were female. In GD, 87.5% of patients indicated that they preferred oral intake of medications to subcutaneous injection (12.5%). In GR, 84.2% declared a preference for oral administration over subcutaneous injection (15.8%). In GF, a surprisingly high proportion of patients (73.3%; p < 0.001) declared that they preferred subcutaneous administration of medications over the oral route (26.7%). Overall, the rate of compliance with antithrombotic drug therapy was very high, at 99%.

CONCLUSIONS

intake of the NOAs dabigatran and rivaroxaban following hospital discharge is entirely the responsibility of the patient; a high level of patient compliance with these drugs must therefore be demonstrated in order for them to become well accepted within the medical community. The results of this study showed a very high level of compliance both with orally and subcutaneously administered drugs.

LEVEL OF EVIDENCE

Level I, randomized clinical study.

Venous Thromboembolism After Knee Arthroscopy in Undiagnosed Familial Thrombophilia

Venous thromboembolism is uncommon after knee arthroscopy, and there are no guidelines for thromboprophylaxis in elective routine knee arthroscopy. Preoperative evaluation of common thrombophilias should provide guidance for postarthroscopy thromboprophylaxis in otherwise healthy patients who are at high risk for venous thromboembolism. This study assessed 10 patients with venous thromboembolism after total hip or knee arthroplasty. Patients were assessed if venous thromboembolism occurred within 6 months after knee arthroscopy (n=10) or total hip or knee arthroplasty (n=21). This study assessed gene mutations (factor V Leiden, prothrombin G20210A, plasminogen activator inhibitor, methylenetetrahydrofolate reductase) and serologic thrombophilias (high levels of factors VIII and XI, homocysteine, anticardiolipin immunoglobulin G and immunoglobulin M antibodies, and lupus anticoagulant; low antigenic protein C, S, and free S; and antithrombin III deficiency). The same coagulation data were obtained for normal subjects (n=110). The major thrombophilias in the arthroscopy group were factor V Leiden heterozygosity (40%), high factor VIII level (50%), and high homocysteine (30%). The respective values in control subjects were 2% (P=.0004), 7% (P=.0011), and 5% (P=.02). When the arthroscopy group was compared with the 21 patients who had venous thromboembolism after total hip or knee arthroplasty, the sole difference was factor V Leiden heterozygosity, which was 40% vs 0%, respectively (P=.007). Although venous thromboembolism after knee arthroscopy is uncommon, to identify high-risk patients and guide postoperative thromboprophylaxis, the authors suggest routine preoperative measurement of 3 common familial thrombophilias: factor V Leiden, factor VIII, and homocysteine. [Orthopedics. 2016; 39(6):e1052-e1057.].

Safety and efficacy of new oral anticoagulants and low-molecular-weight heparins compared with aspirin in patients undergoing total knee and hip replacements

BACKGROUND

There has been much debate recently on the best type of thromboprophylaxis following elective total joint replacement surgery.

OBJECTIVE

This study aims to compare rates of venous thromboembolism (VTE), gastro-intestinal (GI) bleeding and mortality events, with use of new oral anticoagulants (NOAC) or low-molecular-weight heparins (LMWHs) compared with aspirin in patients undergoing total joint replacement.

METHODS

A population-based retrospective cohort study was performed using the Clinical Practice Research Datalink. Patients ≥18 years of age who had undergone total knee (n = 3261) or hip replacement (THR (n = 4016)) between 2008 and 2012 were included. Within this population, three cohorts were selected, based on their first prescription within the 35-day period after surgery: use of NOACs only, LMWHs only and aspirin only. Incidence rates were calculated, and Cox proportional hazard models were fitted to estimate the risk of VTE, GI bleeding and all-cause mortality with the use of NOACs and LMWHs compared with aspirin use after total knee replacement and THR. We statistically adjusted our analyses for lifestyle factors, comorbidities and concomitant drug use.

RESULTS

Total knee replacement and THR patients currently on LMWHs had higher risk of VTE (HR = 17.2 (6.9-43.0) and HR = 39.5 (18.0-87.0), respectively), GI bleeding (HR = 20.9 (1.9-232.3) and HR = 2.0 (0.2-17.2), respectively) and all-cause mortality (HR = 4.3 (1.7-12.4) and HR = 4.0 (2.4-6.7), respectively). NOAC use was associated with an increased risk of GI bleeding in patients undergoing THR surgery.

CONCLUSIONS

In contrast to previous studies, we found an increased risk of VTE, GI bleeding and all-cause mortality with the use of LMWHs compared with aspirin. Risk of GI bleeding was increased with the use of NOACs compared with aspirin use after THR surgery. Copyright © 2016 John Wiley & Sons, Ltd.