Darexaban (YM150) versus enoxaparin for the prevention of venous thromboembolism after total hip arthroplasty: a randomised phase IIb dose confirmation study (ONYX-3)

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.

Twice- or Once-Daily Dosing of Direct Oral Anticoagulants, a systematic review and meta-analysis

AIM

The direct oral anticoagulants (DOAC) have similar half-lives, but the dosing regimen varies between once daily (QD) or twice daily (BID). For some prescribers, the QD regimen improves compliance. Others prefer BID regimens to promote better stability of plasma concentrations, particularly in the event of missed doses. Limited level of evidence provides guidance about the best treatment strategy. The purpose of this study was to compare the treatment effect of QD vs. BID administration of DOACs in major orthopedic surgery (MOS), non-valvular atrial fibrillation (NVAF), venous thromboembolism (VTE), and acute coronary syndrome (ACS).

METHODS

We conducted a systematic review up to April 2020. We included phase II clinical trials comparing DOAC QD vs BID with same daily dose. We extracted data for the occurrence of major thrombosis (proximal deep vein thrombosis, pulmonary embolism, myocardial infarction, ischemic stroke) and major hemorrhage (ISTH criteria and recommendations of the European Medicines Agency for surgical patients). Relative risks (RR) were combined using a fixed and random effects weighted meta-analysis.

RESULTS

Twelve randomized, controlled, phase II trials were included (10,716 patients), representing 24 dosing regimen comparisons of apixaban, darexaban, edoxaban, rivaroxaban, letaxaban, and dabigatran. There was no difference for major thrombotic event (RR_BID/QD = 1.06, 95%IC 0.86-1.30) nor for major bleeding (RR_BID/QD = 1.02, 95%IC 0.84-1.23) between the BID vs QD regimens, without heterogeneity (I² = 0%).

CONCLUSION

Our study does not support a global difference in term of efficacy and safety of the BID and QD regimens of DOAC in MOS, NVAF, VTE and ACS.

American Society of Hematology 2019 guidelines for management of venous thromboembolism: prevention of venous thromboembolism in surgical hospitalized patients

BACKGROUND

Venous thromboembolism (VTE) is a common source of perioperative morbidity and mortality.

OBJECTIVE

These evidence-based guidelines from the American Society of Hematology (ASH) intend to support decision making about preventing VTE in patients undergoing surgery.

METHODS

ASH formed a multidisciplinary guideline panel balanced to minimize bias from conflicts of interest. The McMaster University GRADE Centre supported the guideline-development process, including performing systematic reviews. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to assess evidence and make recommendations, which were subject to public comment.

RESULTS

The panel agreed on 30 recommendations, including for major surgery in general (n = 8), orthopedic surgery (n = 7), major general surgery (n = 3), major neurosurgical procedures (n = 2), urological surgery (n = 4), cardiac surgery and major vascular surgery (n = 2), major trauma (n = 2), and major gynecological surgery (n = 2).

CONCLUSIONS

For patients undergoing major surgery in general, the panel made conditional recommendations for mechanical prophylaxis over no prophylaxis, for pneumatic compression prophylaxis over graduated compression stockings, and against inferior vena cava filters. In patients undergoing total hip or total knee arthroplasty, conditional recommendations included using either aspirin or anticoagulants, as well as for a direct oral anticoagulant over low-molecular-weight heparin (LMWH). For major general surgery, the panel suggested pharmacological prophylaxis over no prophylaxis, using LMWH or unfractionated heparin. For major neurosurgery, transurethral resection of the prostate, or radical prostatectomy, the panel suggested against pharmacological prophylaxis. For major trauma surgery or major gynecological surgery, the panel suggested pharmacological prophylaxis over no prophylaxis.

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.

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.

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

OBJECTIVES

To analyze the efficacy and safety of direct factor Xa inhibitors for thromboprophylaxis after total hip or knee replacement. To delineate the dose response effect of direct factor Xa inhibitors. To compare the efficacy between any two direct factor Xa inhibitors.

DESIGN

Systemic review, traditional meta-analysis, dose-response meta-analysis and network meta-analysis.

DATA SOURCE

PubMed, EMBASE and Cochrane Library.

STUDY SELECTION

Randomized controlled trials of rivaroxaban, apixaban, betrixaban, darexaban and edoxaban were compared with enoxaparin for thromboprophylaxis after total hip or knee replacement. Two reviewers independently checked the quality of RCTs. Another two investigators independently extracted data. The primary efficacy outcomes (composite of deep venous thrombosis, non-fatal pulmonary embolism and death of all causes) and the primary bleeding outcomes (major bleeding and non-major but clinically relevant bleeding) were summarized for meta-analysis. Stata software was used for traditional meta-analysis and dose-response meta-analysis, and Winbugs software was used for network meta-analysis.

RESULTS

Twenty trials with 38,507 subjects in the intention-to-treat population were included. Compared with enoxaparin, the risk of total venous thromboembolism was lower with rivaroxaban (relative risk 0.70, 95% confidence interval 0.60 to 0.81), apixaban (0.62, 0.47 to 0.81), and edoxaban (0.62, 0.39 to 0.97) and similar to darexaban (0.96, 0.84 to 1.11) and betrixaban (1.28, 0.97 to 1.68). Compared with enoxaparin, the risk of major or clinically relevant non-major bleeding was higher with rivaroxaban (1.52, 1.14 to 2.02), lower with betrixaban (0.34, 0.14 to 0.84) and similar to apixaban (0.88, 0.73 to 1.05), darexaban (0.85, 0.66 to 1.09) or edoxaban (1.30, 0.72 to 2.33). The risk of major and clinically relevant non-major bleeding of rivaroxaban had a linear relationship with its treatment doses; the risk of total venous thromboembolism of betrixaban and darexaban had linear relationships with their respective treatment doses. There was no linear nor non-liner relationships between the effect of apixaban and its treatment dose. The ranking of total venous thromboembolism risk from low to high was: rivaroxaban, apixaban, edoxaban, enoxaparin, darexaban, and betrixaban. The ranking of major and clinically relevant non-major bleeding from low to high was: betrixaban, enoxaparin, darexaban, edoxaban, apixaban, and rivaroxaban.

CONCLUSIONS

Direct oral factor Xa inhibitors are more effective to prevent venous thromboembolism after total hip or knee replacement. Their anticoagulant effect was not necessarily compromised with a higher bleeding risk. Rivaroxaban, apixaban and edoxaban showed a better anticoagulant effect, as compared with enoxaparin. Rivaroxaban had a higher bleeding rate, while apixaban and edoxaban did not show significantly higher bleeding risks.