Dabigatran etexilate prevents venous thromboembolism after total knee arthroplasty in Japanese patients with a safety profile comparable to placebo

Pharmacotherapy for Venous Thromboprophylaxis following Total Hip or Knee Arthroplasty: A Systematic Review and Network Meta-analysis

The optimal pharmacological prophylaxis for venous thromboembolism (VTE) after hip or knee arthroplasty is uncertain. We conducted a systematic review and network meta-analysis to compare the efficacy and safety of various medications. We searched multiple databases for randomized clinical trials (RCTs) comparing medications (including factor Xa inhibitors, factor IIa inhibitor, warfarin, unfractionated heparin [UFH], low-molecular-weight heparin [LMWH], aspirin, pentasaccharide) for VTE prophylaxis post-arthroplasty. Outcomes included any postoperative VTE identified with screening, major bleeding, and death. We used LMWH as the main comparator for analysis and performed trial sequential analysis (TSA) for each pairwise comparison. Certainty of evidence was assessed using GRADE (Grading of Recommendations, Assessments, Developments and Evaluations). We analyzed 70 RCTs (55,841 participants). Factor Xa inhibitors decreased postoperative VTE significantly compared with LMWH (odds ratio [OR]: 0.55, 95% confidence interval [CI]: 0.44-0.68, high certainty). Pentasaccharides probably reduce VTE (OR: 0.61, 95% CI: 0.36-1.02, moderate certainty), while the factor IIa inhibitor dabigatran may reduce VTE (OR: 0.75, 95% CI: 0.40-1.42, low certainty). UFH probably increases VTE compared with LMWH (OR: 1.31, 95% CI: 0.91-1.89, moderate certainty), and other agents like warfarin, aspirin, placebo, and usual care without thromboprophylaxis increase VTE (high certainty). Factor Xa inhibitors may not significantly affect major bleeding compared with LMWH (OR: 1.06, 95% CI: 0.81-1.39, low certainty). No medications had a notable effect on mortality compared with LMWH (very low certainty). TSA suggests sufficient evidence for the benefit of factor Xa inhibitors over LMWH for VTE prevention. Compared with LMWH and aspirin, factor Xa inhibitors are associated with reduced VTE after hip or knee arthroplasty, without an increase in bleeding and likely no impact on mortality.

New Oral Anticoagulants for Venous Thromboembolism Prophylaxis in Total Hip and Knee Arthroplasty: A Systematic Review and Network Meta-Analysis

Background: There is controversy over whether use of new oral anticoagulants (NOACs) associates with increased hemorrhage risk compared with non-NOAC. Meanwhile, determining which NOAC to use remains unclear. We aimed to summarize the evidence about NOACs in venous thromboembolism (VTE) prevention for patients with total hip and knee arthroplasty (THA and TKA).

Methods: We searched RCTs assessing NOACs for VTE prophylaxis in adults undergoing THA and TKA in Medline, Embase, and Cochrane up to May 2021. Primary outcomes were VTE [included deep vein thrombosis (DVT) and pulmonary embolism (PE)], major VTE, and major bleeding. The rank probabilities of each treatment were summarized by the surface under the cumulative ranking curve area (SUCRA).

Results: 25 RCTs with 42,994 patients were included. Compared with non-NOAC, NOACs were associated with a decreased risk of VTE (RR 0.68; 95% CI 0.55–0.84) and major VTE (RR = 0.52; 95% CI 0.35–0.76). Additionally, rivaroxaban, apixaban, and edoxaban but not dabigatran and betrixaban, did confer a higher efficacy compared with non-NOAC. None of the individual NOACs increased the risk of bleeding, while apixaban and betrixaban were even associated with a decreased risk of bleeding. In the comparison of different NOACs, rivaroxaban was associated with the greatest benefits in VTE (SUCRA = 79.6), DVT (SUCRA = 88.8), and major VTE (SUCRA = 89.9) prevention. Furthermore, subgroup analysis confirmed that NOACs associated with a higher efficacy tendency in patients with follow-up duration <60 days than follow-up duration ≥60 days.

Conclusion: Evidence suggests that NOACs exert more benefits on VTE prophylaxis, and none of the individual NOACs increased hemorrhage compared with non-NOAC. Among various NOACs, rivaroxaban is recommended in patients with lower bleeding risk, and apixaban is recommended in patients with higher bleeding risk.

Systematic Review Registration: [https://www.crd.york.ac.uk/prospero/], identifier [CRD42021266890].

[SBA 2020: Regional anesthesia guideline for using anticoagulants update]

The development of protocols to prevent perioperative Venous Thromboembolism (VTE) and the introduction of increasingly potent antithrombotic drugs have resulted in concerns of increased risk of neuraxial bleeding. Since the Brazilian Society of Anesthesiology (SBA) 2014 guideline, new oral anticoagulant drugs were approved by international regulating agencies, and by ANVISA. Societies and organizations that try to approach concerns through guidelines have presented conflicting perioperative management recommendations. As a response to these issues and to the need for a more rational approach, managements were updated in the present narrative revision, and guideline statements made. They were projected to encourage safe and quality patient care, but cannot assure specific results. Like any clinical guide recommendation, they are subject to review as knowledge grows, on specific complications, for example. The objective was to assess safety aspects of regional analgesia and anesthesia in patients using antithrombotic drugs, such as: possible technique-associated complications; spinal hematoma-associated risk factors, prevention strategies, diagnosis and treatment; safe interval for discontinuing and reinitiating medication after regional blockade.

Risk of Major Gastrointestinal Bleeding With New vs Conventional Oral Anticoagulants: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

There is controversy over whether use of non-vitamin K antagonist oral anticoagulants (NOACs) associates with increased risk of major gastrointestinal bleeding (GIB) compared with conventional therapies (such as vitamin K antagonists or anti-platelet agents). We performed a systematic review and meta-analysis of data from randomized controlled trials and high-quality real-world studies.

METHODS

We performed a systematic search of the MEDLINE, EMBASE, Cochrane Library, and ClinicalTrials.gov Website databases (through Oct 12, 2018) for randomized controlled trials and high-quality real-world studies that reported major GIB events in patients given NOACs or conventional therapy. Relative risks (RRs) for randomized controlled trials and adjusted hazard ratios (aHRs) for real-world studies were calculated separately using random-effects models.

RESULTS

We analyzed data from 43 randomized controlled trials (183,752 patients) and 41 real-world studies (1,879,428 patients). The pooled major rates of GIB for patients on NOACs (1.19%) vs conventional treatment (0.92%) did not differ significantly (RR from randomized controlled trials, 1.09; 95% CI, 0.91-1.31 and aHR from real-world studies, 1.02; 95% CI, 0.94-1.10; P_interaction=.52). Rivaroxaban, but not other NOACs, was associated with an increased risk for major GIB (RR from randomized controlled trials, 1.39; 95% CI, 1.17-1.65 and aHR from real-world studies, 1.14; 95% CI, 1.04-1.23; P_interaction = .06). Analyses of subgroups, such as patients with different indications, dosage, or follow-up time, did not significantly affect results. Meta-regression analysis failed to detect any potential confounding to impact the primacy outcome.

CONCLUSIONS

In a systematic review and meta-analysis of data from randomized controlled trials and real-world studies, we confirmed that there is no significant difference in risk of major GIB between patients receiving NOACs vs conventional treatment. Rivaroxaban users had a 39% increase in risk for major GIB.

Efficacy and safety of dabigatran for venous thrombosis prophylaxis after knee replacement surgery in Thai patients: a prospective non-randomized controlled trial

Background

Dabigatran, a direct oral anticoagulant, has been approved for the prevention of venous thromboembolism (VTE) after orthopedic surgery in many countries. The efficacy and safety of this agent were most studied in Western countries.

Objective

To assess the efficacy and safety of dabigatran in preventing venous thromboembolic diseases after total knee arthroplasty (TKA) in Asian patients.

Methods

We conducted a prospective nonrandomized controlled study in Thai patients undergoing TKA. Thirty-two patients received 220 mg of dabigatran once daily for 14 days as thromboprophylaxis and 32 patients in the control group received none. The primary efficacy outcome was deep vein thrombosis (DVT), which was identified by color Doppler ultrasonography and/or diagnosed pulmonary embolism (PE). The primary safety outcomes were major bleeding and clinically relevant nonmajor bleeding events.

Results

There were no DVTs or PEs diagnosed in either group. The difference in the composite incidence of major and clinically relevant nonmajor bleedings between the dabigatran and control groups did not reach significant (6.2% vs. 0%, P = 0.15).

Conclusion

Dabigatran might have no clear benefit for the prevention of VTE after TKA in Thai patients. We do not recommend the routine use of dabigatran as a chemical thromboprophylaxis after TKA in Thai patients. To determine the safety profile, further study with larger sample sizes is required.

Combined intravenous and intra-articular tranexamic acid administration in total knee arthroplasty for preventing blood loss and hyperfibrinolysis: A randomized controlled trial

BACKGROUND

Total knee arthroplasty (TKA) is a surgical procedure to replace the weight-bearing surfaces of the knee joint to relieve pain and disability. However, blood loss and fibrinolytic activity, accounting for a poor prognosis following TKA operation, were relieved by fibrinolytic inhibitor tranexamic acid (TXA). For a better application of TXA function, we explored the effect of intravenous injection (IV) of TXA combined with intra-articular injection (IA) of TXA in patients after TKA.

METHODS

Patients admitted from Weifang People's Hospital from January 2015 to December 2016 who received TKA were injected with 20 mg/kg TXA by IV before TKA (n = 50), 3.0 g TXA by IA after TKA (n = 50), or combination of 20 mg/kg TXA by IV before TKA and 3.0 g TXA by IA after TKA (n = 50). Knee function was assessed using HSS, KSS, NASS, and ROM. In addition, the total blood loss (TBL), hidden blood loss (HBL), maximum hemoglobin (Hb) drop, fibrinolytic activity, as well as incidence of thromboembolism were measured. The patients were followed up for 6 months. The deadline for follow-up was June 2017 and the incidence of thromboembolism events within 6 months after operation was counted.

RESULTS

HSS, KSS, NASS scores, and ROM were elevated after patients receiving TKA. Patients received IV plus IA TXA has decreased TBL, HBL, and maximum Hb drop than those received IV TXA-alone and IA TXA-alone, with reductions in FDP and D-dimer, indicating that IV plus IA TXA injection is superior to prevent blood loss and hyperfibrinolysis during TKA. Age, sex, type of femoral prosthesis, and the injection method of TXA were risk factors for HBL of patients after receiving TKA.

CONCLUSIONS

The aforementioned results demonstrate that TKA is an effective surgery, and IV plus IA TXA injection functions more effectively in reducing blood loss and fibrinolytic activity in patients, which is a clinical factor of occult hemorrhage.

Oral anticoagulants for primary prevention, treatment and secondary prevention of venous thromboembolic disease, and for prevention of stroke in atrial fibrillation: systematic review, network meta-analysis and cost-effectiveness analysis

BACKGROUND

Warfarin is effective for stroke prevention in atrial fibrillation (AF), but anticoagulation is underused in clinical care. The risk of venous thromboembolic disease during hospitalisation can be reduced by low-molecular-weight heparin (LMWH): warfarin is the most frequently prescribed anticoagulant for treatment and secondary prevention of venous thromboembolism (VTE). Warfarin-related bleeding is a major reason for hospitalisation for adverse drug effects. Warfarin is cheap but therapeutic monitoring increases treatment costs. Novel oral anticoagulants (NOACs) have more rapid onset and offset of action than warfarin, and more predictable dosing requirements.

OBJECTIVE

To determine the best oral anticoagulant/s for prevention of stroke in AF and for primary prevention, treatment and secondary prevention of VTE.

DESIGN

Four systematic reviews, network meta-analyses (NMAs) and cost-effectiveness analyses (CEAs) of randomised controlled trials.

SETTING

Hospital (VTE primary prevention and acute treatment) and primary care/anticoagulation clinics (AF and VTE secondary prevention).

PARTICIPANTS

Patients eligible for anticoagulation with warfarin (stroke prevention in AF, acute treatment or secondary prevention of VTE) or LMWH (primary prevention of VTE).

INTERVENTIONS

NOACs, warfarin and LMWH, together with other interventions (antiplatelet therapy, placebo) evaluated in the evidence network.

MAIN OUTCOME MEASURES

Efficacy Stroke, symptomatic VTE, symptomatic deep-vein thrombosis and symptomatic pulmonary embolism. Safety Major bleeding, clinically relevant bleeding and intracranial haemorrhage. We also considered myocardial infarction and all-cause mortality and evaluated cost-effectiveness.

DATA SOURCES

MEDLINE and PREMEDLINE In-Process & Other Non-Indexed Citations, EMBASE and The Cochrane Library, reference lists of published NMAs and trial registries. We searched MEDLINE and PREMEDLINE In-Process & Other Non-Indexed Citations, EMBASE and The Cochrane Library. The stroke prevention in AF review search was run on the 12 March 2014 and updated on 15 September 2014, and covered the period 2010 to September 2014. The search for the three reviews in VTE was run on the 19 March 2014, updated on 15 September 2014, and covered the period 2008 to September 2014.

REVIEW METHODS

Two reviewers screened search results, extracted and checked data, and assessed risk of bias. For each outcome we conducted standard meta-analysis and NMA. We evaluated cost-effectiveness using discrete-time Markov models.

RESULTS

Apixaban (Eliquis^®, Bristol-Myers Squibb, USA; Pfizer, USA) [5 mg bd (twice daily)] was ranked as among the best interventions for stroke prevention in AF, and had the highest expected net benefit. Edoxaban (Lixiana^®, Daiichi Sankyo, Japan) [60 mg od (once daily)] was ranked second for major bleeding and all-cause mortality. Neither the clinical effectiveness analysis nor the CEA provided strong evidence that NOACs should replace postoperative LMWH in primary prevention of VTE. For acute treatment and secondary prevention of VTE, we found little evidence that NOACs offer an efficacy advantage over warfarin, but the risk of bleeding complications was lower for some NOACs than for warfarin. For a willingness-to-pay threshold of > £5000, apixaban (5 mg bd) had the highest expected net benefit for acute treatment of VTE. Aspirin or no pharmacotherapy were likely to be the most cost-effective interventions for secondary prevention of VTE: our results suggest that it is not cost-effective to prescribe NOACs or warfarin for this indication.

CONCLUSIONS

NOACs have advantages over warfarin in patients with AF, but we found no strong evidence that they should replace warfarin or LMWH in primary prevention, treatment or secondary prevention of VTE.

LIMITATIONS

These relate mainly to shortfalls in the primary data: in particular, there were no head-to-head comparisons between different NOAC drugs.

FUTURE WORK

Calculating the expected value of sample information to clarify whether or not it would be justifiable to fund one or more head-to-head trials.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42013005324, CRD42013005331 and CRD42013005330.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

The diagnosis and treatment of venous thromboembolism in asian patients

Although the incidence of venous thromboembolism (VTE) in Asian populations is lower than in Western countries, the overall burden of VTE in Asia has been considerably underestimated. Factors that may explain the lower prevalence of VTE in Asian populations relative to Western populations include the limited availability of epidemiological data in Asia, ethnic differences in the genetic predisposition to VTE, underdiagnoses, low awareness toward thrombotic disease, and possibly less symptomatic VTE in Asian patients. The clinical assessment, diagnostic testing, and therapeutic considerations for VTE are, in general, the same in Asian populations as they are in Western populations. The management of VTE is based upon balancing the treatment benefits against the risk of bleeding. This is an especially important consideration for Asian populations because of increased risk of intracranial hemorrhage with vitamin K antagonists. Non-vitamin K antagonist oral anticoagulants have shown advantages over current treatment modalities with respect to bleeding outcomes in major phase 3 clinical trials, including in Asian populations. Although anticoagulant therapy has been shown to reduce the risk of postoperative VTE in Western populations, VTE prophylaxis is not administered routinely in Asian countries. Despite advances in the management of VTE, data in Asian populations on the incidence, prevalence, recurrence, risk factors, and management of bleeding complications are limited and there is need for increased awareness. To that end, this review summarizes the available data on the epidemiology, risk stratification, diagnosis, and treatment considerations in the management of VTE in Asia.

Persistent Pulmonary Embolism Rates Following Total Knee Arthroplasty Even With Prophylactic Anticoagulants

BACKGROUND

Symptomatic pulmonary embolism (PE), a significant and life-threatening complication following total knee arthroplasty (TKA), has been described as a "never event." Despite a number of advancements in care, PE continues to occur following TKA. This study evaluates symptomatic PE rates over time in TKA patients enrolled in multicenter randomized clinical trials assessing the efficacy of venous thromboembolism prophylaxis regimens.

METHODS

The MEDLINE and Cochrane Central Register of Controlled Trials were searched to identify clinical trials assessing prophylactic anticoagulation in patients undergoing TKA between January 1995 and December 2016. A random effect model was used to combine PE rates across studies. The pooled proportion of symptomatic PEs was calculated and heterogeneity was quantified with the I² statistic. A 95% prediction interval was constructed to examine what the expected range in the proportion of symptomatic PEs would be in future studies. Meta-regression was used to explore the effect of time on the rate of symptomatic PEs.

RESULTS

A total of 18 studies representing 27,073 patients were included in the meta-analysis. The symptomatic PE rate was 0.37% (95% confidence interval, 0.24%-0.52%). There was significant heterogeneity across studies, I² = 66%. Between 1996 and 2010, the proportion of PEs did not change in the regression analysis. The 95% prediction interval was 0.0002 to 0.0106, indicating that in similar future studies, the true proportion of symptomatic PEs would range from 0.02% to 1.06%.

CONCLUSION

Over a 14-year period, the symptomatic PE rate after TKA was relatively constant even when patients received potent anticoagulation. These results suggest that some patients may have a genetic predisposition to develop a PE and more effective risk stratification protocols need to be developed to make sure patients receive appropriate anticoagulation.

Pharmacokinetics and pharmacodynamics in Japanese and Caucasian subjects after oral administration of dabigatran etexilate

Ethnic differences in drug disposition may potentially influence therapeutic response to dabigatran, a reversible direct thrombin inhibitor used for the prevention and/or treatment of various thromboembolic disorders. This analysis of data from 18 clinical studies in healthy volunteers and patients with non-valvular atrial fibrillation (AF) or undergoing knee or hip arthroplasty investigated whether there were any clinically relevant differences in the pharmacokinetics and pharmacodynamics of dabigatran, the active form of dabigatran etexilate, between Japanese and Caucasian subjects. In pooled data from 14 phase I trials, total exposure (i.e. area under the plasma concentration-time curve [AUC]) after administration of dabigatran 150 mg once or twice-daily was on average 20% higher in Japanese than Caucasian subjects (median [10th to 90th percentile] 1,110 [644–1,824] vs. 924 [420–1,654] ng·h/ml) although the difference between the groups was not significant. Within-trial comparisons in subjects treated with dabigatran 150 mg twice-daily showed that AUC and maximum plasma concentration differed by less than 10% between the two groups. In patients with AF, trough concentrations after administration of 150 mg twice-daily were similar in Japanese and Caucasian subjects (80.1 [34.5–193.8] vs. 71.0 [34.0–190] ng/ml). Various factors, including body weight and renal clearance, may explain these observed pharmacokinetic differences. The relationship between plasma concentration and coagulation markers was similar and indicative of no difference in the exposure-pharmacodynamic response between these two groups. In conclusion, the results of this analysis show that the pharmacokinetics and pharmacodynamics of dabigatran are similar in Japanese and Caucasian subjects and suggest that there is no need for dose adjustment of dabigatran in Japanese subjects.

Risk of Gastrointestinal Bleeding in Patients Taking Non-Vitamin K Antagonist Oral Anticoagulants: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

Non-vitamin K antagonist oral anticoagulants (NOACs) are convenient and effective in the prevention and treatment of venous thromboembolism and the prevention of stroke in patients with atrial fibrillation. However, these drugs have been associated with an increased risk of gastrointestinal (GI) bleeding. We conducted a systematic review and meta-analysis to determine the risk of GI bleeding in patients receiving these drugs.

METHODS

We searched the EMBASE, Medline, Cochrane, and ISI Web of knowledge databases through January 2016 for randomized trials that compared NOACs with conventional anticoagulants for approved indications. We conducted a meta-analysis, reporting odds ratios (ORs) with 95% confidence intervals (CIs). The primary outcome was major GI bleeding. Secondary outcomes included clinically relevant nonmajor bleeding and upper and lower GI bleeding. We performed a priori subgroup analyses by individual drug.

RESULTS

Our analysis included a total of 43 randomized trials, comprising 166,289 patients. There was no difference between NOACs and conventional anticoagulants in the risk of major bleeding (1.5% vs 1.3%, respectively; OR, 0.98; 95% CI, 0.80-1.21), clinically relevant nonmajor bleeding (0.6% vs 0.6%, respectively; OR, 0.93; 95% CI, 0.64-1.36), upper GI bleeding (1.5% vs 1.6%, respectively; OR, 0.96; 95% CI, 0.77-1.20), or lower GI bleeding (1.0% vs 1.0%, respectively; OR, 0.88; 95% CI, 0.67-1.15). Dabigatran (2.0% vs 1.4%, respectively; OR, 1.27; 95% CI, 1.04-1.55) and rivaroxaban (1.7% vs 1.3%, respectively; OR, 1.40; 95% CI, 1.15-1.70) were associated with increased odds of major GI bleeding compared with conventional anticoagulation, whereas no difference was found for apixaban (0.6% vs 0.7%, respectively; OR, 0.81; 95% CI, 0.64-1.02) or edoxaban (1.9% vs 1.6%, respectively; OR, 0.93; 95% CI, 0.78-1.11). These subgroup findings were not observed in other sensitivity analyses.

CONCLUSIONS

In a systematic review and meta-analysis, we found risk of major GI bleeding to be similar between NOACs and conventional anticoagulation. Dabigatran and rivaroxaban, however, may be associated with increased odds of major GI bleeding. Further high-quality studies are needed to characterize GI bleeding risk among NOACs.

Anticoagulation and Neuraxial/Peripheral Anesthesia

Novel anticoagulants (NAGs) have emerged as the preferred alternatives to vitamin K antagonists. In patients being considered for regional anesthesia, these drugs present a layer of complexity in the preprocedure evaluation. There are no established tests to monitor anticoagulant activity and our experience is short with these drugs. These authors believe it is important to review the relevant hematology, orthopedics, and anesthesiology literature to provide a valuable reference for the clinician who is met with these challenges. In addition to discussing NAGs, we also review the existing American Society of Regional Anesthesia guidelines for heparin, low-molecular-weight heparin, and antiplatelet agents.

Post-operative arterial thrombosis with non-vitamin K antagonist oral anticoagulants after total hip or knee arthroplasty

The incidence of post-operative arterial thrombosis (AT) (acute myocardial infarction [AMI] and ischaemic stroke) is increased in patients undergoing total hip replacement (THR) or total knee replacement (TKR). We compared the incidence of post-operative AT in non-vitamin K antagonist oral anticoagulants (NOACs)-treated and enoxaparin-treated patients, performing a systematic review of phase III randomised controlled trials (RCTs) of venous thromboembolism (VTE) prophylaxis in THR and TKR. Studies were identified by electronic search of MEDLINE and EMBASE database until July 2014. Differences between NOACs and enoxaparin groups in the efficacy and safety outcomes were expressed as odds ratios (ORs) with pertinent 95 % confidence intervals (95 % CI). Statistical heterogeneity was assessed with the I² statistic. Eleven phase III RCTs for a total of 31,319 patients were included. Patients underwent TKR in six studies and THR in five studies. The NOACs under study were dabigatran (four studies), apixaban (three studies) and rivaroxaban (four studies). AT occurred in 0.23 % of patients on NOACs and in 0.27 % of patients on enoxaparin: the OR at fixed-effect model was 0.86 (95 % CI 0.53-1.40; I² 11 %). No differences in AT incidence among the three NOACs were observed. The incidence of major and clinically relevant bleeding was similar in NOACs and enoxaparin groups (OR 1.03, 95 % CI 0.92-1.15; I² 38 %). In conclusion, in RCTs of pharmacological VTE prophylaxis in patients undergoing THR or TKR, there was no difference in the incidence of post-operative AT among patients treated with NOACs, compared to those treated with enoxaparin.

Dabigatran etexilate and risk of myocardial infarction, other cardiovascular events, major bleeding, and all-cause mortality: a systematic review and meta-analysis of randomized controlled trials

Background

Signals of an increased risk of myocardial infarction (MI) have been identified with dabigatran etexilate in randomized controlled trials (RCTs).

Methods and Resules

We conducted searches of the published literature and a clinical trials registry maintained by the drug manufacturer. Criteria for inclusion in our meta‐analysis included all RCTs and the availability of outcome data for MI, other cardiovascular events, major bleeding, and all‐cause mortality. Among the 501 unique references identified, 14 RCTs fulfilled the inclusion criteria. Stratification analyses by comparators and doses of dabigatran etexilate were conducted. Peto odds ratio (OR_PETO) values using the fixed‐effect model (FEM) for MI, other cardiovascular events, major bleeding, and all‐cause mortality were 1.34 (95% CI 1.08 to 1.65, P=0.007), 0.93 (95%CI 0.83 to 1.06, P=0.270), 0.88 (95% CI 0.79 to 0.99, P=0.029), and 0.89 (95% CI 0.80 to 1.00, P=0.041). When compared with warfarin, OR_PETO values using FEM were 1.41 (95% CI 1.11 to 1.80, P=0.005), 0.94 (95%CI 0.83 to 1.06, P=0.293), 0.85 (95% CI 0.76 to 0.96, P=0.007), and 0.90 (95% CI 0.81 to 1.01, P=0.061), respectively. In RCTs using the 150‐mg BID dosage, the OR_PETO values using FEM were 1.45 (95% CI 1.11 to 1.91, P=0.007), 0.95 (95% CI 0.82 to 1.09, P=0.423), 0.92 (95% CI 0.81 to 1.05, P=0.228), and 0.88 (95% CI 0.78 to 1.00, P=0.045), respectively. The results of the 110‐mg BID dosage were mainly driven by the RE‐LY trial.

Conclusions

This meta‐analysis provides evidence that dabigatran etexilate is associated with a significantly increased risk of MI. This increased risk should be considered taking into account the overall benefit in terms of major bleeding and all‐cause mortality.

Review article: Venous thromboembolism after total joint replacement

Venous thromboembolism can occur in up to 84% of cases following total joint replacement. It can result in pain, swelling, chronic post-thrombotic syndrome, and pulmonary embolism. Its prevention is vital to the success of the surgery. To achieve a safe and effective prophylaxis, a combination of mechanical and pharmacologic agents should be used. New generation of thromboprophylactic agents target different factors of the coagulation pathway.

[Dabigatran: transforming the management of oral anticoagulation]

The utility of oral anticoagulation with warfarin in thromboembolic disease has been demonstrated for several decades, although these drugs have significant problems in terms of adequate control, interactions and risk of bleeding. In the last decade, new anticoagulants have emerged. The first was dabigatran with a demonstrated anticoagulant effect approaching the ideal anticoagulant profile. The view that dabigatran transforms oral anticoagulation therapy has arisen from the RE-VOLUTION program, with more than 34000 patients analyzed. This program has confirmed the value of oral anticoagulation with dabigatran compared with other anticoagulants; this drug eliminates all the drawbacks of warfarin, benefitting both patients and the healthcare system. The growth of the aging population has increased the number of risk situations in which anticoagulation is used. There is now a drug that meets the criteria for the ideal anticoagulant, transforming the management of oral anticoagulation. The findings demonstrated with dabigatran in prior studies are progressively being transferred to clinical practice. Following the usual development of new drugs, and according to the latest Laurence Desmond stages, results in agreement with those of previous studies are expected, namely, indisputable improvements in oral anticoagulation for patients and the health system.

Cardiovascular outcomes during treatment with dabigatran: comprehensive analysis of individual subject data by treatment

Background

Dabigatran 150 mg twice daily was shown to be superior to warfarin in preventing stroke in subjects with nonvalvular atrial fibrillation (SPAF) in the RE-LY (Randomized Evaluation of Long-term anticoagulation therapY) trial. Numerically, more myocardial infarctions occurred in patients receiving dabigatran compared with well-controlled warfarin. This observation prompted a comprehensive analysis of cardiovascular outcomes, including myocardial infarction, in all completed Phase II and III trials of dabigatran etexilate.

Methods

The analysis included comparisons of dabigatran with warfarin, enoxaparin, and placebo. Data were analyzed for the occurrence of cardiovascular events from 14 comparative trials (n = 42,484) in five different indications. Individual study data were evaluated, as well as pooled subject-level data grouped by comparator.

Results

In the pooled analysis of individual patient data comparing dabigatran with warfarin (SPAF and venous thromboembolism treatment indications), myocardial infarction occurrence favored warfarin (odds ratio [OR] 1.30, 95% confidence interval [CI] 0.96–1.76 for dabigatran 110 mg twice daily and OR 1.42, 95% CI 1.07–1.88 for dabigatran 150 mg twice daily). The clinically relevant composite endpoint of myocardial infarction, total stroke, and vascular death demonstrated numerically fewer events in dabigatran 150 mg patients (OR 0.87, 95% CI 0.77–1.00), but was similar for dabigatran 110 mg (OR 0.99, 95% CI 0.87–1.13). Dabigatran had similar myocardial infarction rates when compared with enoxaparin or placebo.

Conclusion

These analyses suggest a more protective effect of well-controlled warfarin, but not enoxaparin, compared with dabigatran in preventing myocardial infarction in multiple clinical settings. Dabigatran showed an overall positive benefit-risk ratio for multiple clinically important cardiovascular composite endpoints in all evaluated clinical indications. In conclusion, these data suggest that myocardial infarction is not an adverse drug reaction associated with use of dabigatran.

New oral anticoagulants increase risk for gastrointestinal bleeding: a systematic review and meta-analysis

BACKGROUND & AIMS

A new generation of oral anticoagulants (nOAC), which includes thrombin and factor Xa inhibitors, has been shown to be effective, but little is known about whether these drugs increase patients' risk for gastrointestinal bleeding (GIB). Patients who require OAC therapy frequently have significant comorbidities and may also take aspirin and/or thienopyridines. We performed a systematic review and meta-analysis of the risk of GIB and clinically relevant bleeding in patients taking nOAC.

METHODS

We queried MEDLINE, EMbase, and the Cochrane library (through July 2012) without language restrictions. We analyzed data from 43 randomized controlled trials (151,578 patients) that compared nOAC (regardless of indication) with standard care for risk of bleeding (19 trials on GIB). Odds ratios (ORs) were estimated using a random-effects model. Heterogeneity was assessed with the Cochran Q test and the Higgins I(2) test.

RESULTS

The overall OR for GIB among patients taking nOAC was 1.45 (95% confidence interval [CI], 1.07-1.97), but there was substantial heterogeneity among studies (I2, 61%). Subgroup analyses showed that the OR for atrial fibrillation was 1.21 (95% CI, 0.91-1.61), for thromboprophylaxis after orthopedic surgery the OR was 0.78 (95% CI, 0.31-1.96), for treatment of venous thrombosis the OR was 1.59 (95% CI, 1.03-2.44), and for acute coronary syndrome the OR was 5.21 (95% CI, 2.58-10.53). Among the drugs studied, the OR for apixaban was 1.23 (95% CI, 0.56-2.73), the OR for dabigatran was 1.58 (95% CI, 1.29-1.93), the OR for edoxaban was 0.31 (95% CI, 0.01-7.69), and the OR for rivaroxaban was 1.48 (95% CI, 1.21-1.82). The overall OR for clinically relevant bleeding in patients taking nOAC was 1.16 (95% CI, 1.00-1.34), with similar trends among subgroups.

CONCLUSIONS

Studies on treatment of venous thrombosis or acute coronary syndrome have shown that patients treated with nOAC have an increased risk of GIB, compared with those who receive standard care. Better reporting of GIB events in future trials could allow stratification of patients for therapy with gastroprotective agents.

[Dabigatran etexilate use among older adults in a home-care system after hip or knee replacement surgery]

INTRODUCTION

Hip replacement surgery (HRS) and knee replacement surgery (KRS) require long-term deep venous thrombosis (DVT) prophylaxis. This study describes dabigatran etexilate (DE) use in post-surgical older adults who underwent HRS and KRS in a clinical practice setting in a home-care system.

MATERIAL AND METHODS

A retrospective descriptive cohort study included elective HRS and KRS postsurgical older adults under home care receiving either DE (n=76) or enoxaparin (n=80). DE was indicated by using the same selection criteria and dosing as in the RE-MODEL and RE-NOVATE studies. The enoxaparin 40 mg/day patients were included as historic controls when they met the same selection criteria as DE patients. Symptomatic DVT, bleeding rate, re-admission rate and mortality during the 90-day postsurgical period were analyzed.

RESULTS

The mean age of the DE group was 74 (5) years old, with 74% females. There were no significant differences in age, gender and type of replacement between the two groups. There were four DVT in each group (50% proximal), with no significant differences found between groups. There was one pulmonary thromboembolism in the DE group, and one major bleeding in the enoxaparin group. There were no deaths during the 90-day follow-up; however, two re-hospitalizations occurred in the DE group. The details on introducing DE use in our home-care system are also described.

CONCLUSIONS

In appropriately selected older adults DE seems to be an effective choice for DVT prophylaxis in home-care in a clinical practice setting.

The discovery of dabigatran etexilate

Thromboembolic disease is a major cause of mortality and morbidity in the developed world and is caused by an excessive stimulation of coagulation. Thrombin is a key serine protease in the coagulation cascade and numerous efforts have been made to develop safe and effective orally active direct thrombin inhibitors (DTIs). Current anticoagulant therapy includes the use of indirect thrombin inhibitors (e.g., heparins, low-molecular-weight-heparins) and vitamin K antagonists such as warfarin. However there are several caveats in the clinical use of these agents including narrow therapeutic window, parenteral delivery, and food- and drug-drug interactions. Dabigatran is a synthetic, reversible DTI with high affinity and specificity for its target binding both free and clot-bound thrombin, and offers a favorable pharmacokinetic profile. Large randomized clinical trials have demonstrated that dabigatran provides comparable or superior thromboprophylaxis in multiple thromboembolic disease indications compared to standard of care. This minireview will highlight the discovery and development of dabigatran, the first in a class of new oral anticoagulant agents to be licensed worldwide for the prevention of thromboembolism in the setting of orthopedic surgery and stroke prevent in atrial fibrillation.

New prospective for the management of low-risk pulmonary embolism: prognostic assessment, early discharge, and single-drug therapy with new oral anticoagulants

Patients with pulmonary embolism (PE) can be stratified into two different prognostic categories, based on the presence or absence of shock or sustained arterial hypotension. Some patients with normotensive PE have a low risk of early mortality, defined as <1% at 30 days or during hospital stay. In this paper, we will discuss the new prospective for the optimal management of low-risk PE: prognostic assessment, early discharge, and single-drug therapy with new oral anticoagulants. Several parameters have been proposed and investigated to identify low-risk PE: clinical prediction rules, imaging tests, and laboratory markers of right ventricular dysfunction or injury. Moreover, outpatient management has been suggested for low-risk PE: it may lead to a decrease in unnecessary hospitalizations, acquired infections, death, and costs and to an improvement in health-related quality of life. Finally, the main characteristics of new oral anticoagulant drugs and the most recent published data on phase III trials on PE suggest that the single-drug therapy is a possible suitable option. Oral administration, predictable anticoagulant responses, and few drug-drug interactions of direct thrombin and factor Xa inhibitors may further simplify PE home therapy avoiding administration of low-molecular-weight heparin.

Dabigatran etexilate: a review of its use for the prevention of venous thromboembolism after total hip or knee replacement surgery

Dabigatran etexilate (Pradaxa®, Pradax™, Prazaxa®) is indicated for the primary prevention of venous thromboembolic (VTE) events in adults who have undergone elective total hip replacement (THR) or total knee replacement (TKR) surgery. This article reviews the clinical efficacy and tolerability of oral dabigatran etexilate in patients undergoing major orthopaedic surgery, as well as summarizing its pharmacological properties and results of a cost-utility analysis. The discussion of clinical trial data focuses on comparative trials with the EU approved dosage regimen of once-daily subcutaneous enoxaparin sodium 40 mg. Dabigatran etexilate is an oral prodrug of the potent, rapidly acting, reversible, competitive inhibitor of thrombin, dabigatran. Dabigatran has predictable and consistent anticoagulant effects and does not require routine coagulation monitoring or dose titration. In the large, randomized, double-blind, phase III, noninferiority trials, RE-MODEL, RE-NOVATE and RE-NOVATE II, oral dabigatran etexilate, at dosages of 150 and 220 mg once daily, initiated postoperatively was shown to be noninferior to subcutaneous enoxaparin sodium 40 mg once daily (initiated prior to surgery) with regard to the incidence of the composite of total VTE events and all-cause mortality in patients undergoing TKR or THR surgery. In general, oral dabigatran etexilate was well tolerated in clinical trials of patients undergoing major orthopaedic surgery. There were no significant between-group differences in bleeding complications, including major bleeding, clinically relevant non-major bleeding or minor bleeding between the dabigatran etexilate or enoxaparin sodium groups. In addition, a cost-utility analysis from the perspective of the UK National Health Service indicated that dabigatran etexilate 220 mg once daily is dominant (i.e. more effective and less costly) to enoxaparin sodium 40 mg once daily in patients undergoing THR or TKR. Additional head-to-head comparisons would be beneficial to more definitively position dabigatran etexilate relative to other available oral treatment options for VTE prophylaxis, such as rivaroxaban and apixaban. In the meantime, dabigatran etexilate offers a convenient, effective and generally well tolerated treatment option for the prophylaxis of VTE in patients undergoing TKR and THR surgery.

Dabigatran, rivaroxaban, or apixaban versus enoxaparin for thromboprophylaxis after total hip or knee replacement: systematic review, meta-analysis, and indirect treatment comparisons

OBJECTIVE

To analyse clinical outcomes with new oral anticoagulants for prophylaxis against venous thromboembolism after total hip or knee replacement.

DESIGN

Systematic review, meta-analysis, and indirect treatment comparisons.

DATA SOURCES

Medline and CENTRAL (up to April 2011), clinical trials registers, conference proceedings, and websites of regulatory agencies.

STUDY SELECTION

Randomised controlled trials of rivaroxaban, dabigatran, or apixaban compared with enoxaparin for prophylaxis against venous thromboembolism after total hip or knee replacement. Two investigators independently extracted data. Relative risks of symptomatic venous thromboembolism, clinically relevant bleeding, deaths, and a net clinical endpoint (composite of symptomatic venous thromboembolism, major bleeding, and death) were estimated using a random effect meta-analysis. RevMan and ITC software were used for direct and indirect comparisons, respectively.

RESULTS

16 trials in 38,747 patients were included. Compared with enoxaparin, the risk of symptomatic venous thromboembolism was lower with rivaroxaban (relative risk 0.48, 95% confidence interval 0.31 to 0.75) and similar with dabigatran (0.71, 0.23 to 2.12) and apixaban (0.82, 0.41 to 1.64). Compared with enoxaparin, the relative risk of clinically relevant bleeding was higher with rivaroxaban (1.25, 1.05 to 1.49), similar with dabigatran (1.12, 0.94 to 1.35), and lower with apixaban (0.82, 0.69 to 0.98). The treatments did not differ on the net clinical endpoint in direct or indirect comparisons.

CONCLUSIONS

A higher efficacy of new anticoagulants was generally associated with a higher bleeding tendency. The new anticoagulants did not differ significantly for efficacy and safety.

Dabigatran etexilate: an oral direct thrombin inhibitor for the management of thromboembolic disorders

BACKGROUND

Until recently, warfarin was the only oral anticoagulant available in the United States. Its narrow therapeutic index, interpatient variability in dose response, and drug and food interactions make it difficult to use. Dabigatran etexilate (DE) is a new oral direct thrombin inhibitor that was approved in the US and in Canada for the prevention of thromboembolic events in patients with atrial fibrillation (AF), as well as in Europe and Canada for the prevention of venous thromboembolism (VTE).

OBJECTIVE

To discuss the role of DE for the prevention and treatment of VTE, as well as for the prevention of stroke in patients with AF.

METHODS

Peer-reviewed clinical trials, review articles, and treatment guidelines were identified from MEDLINE and the Current Contents database (both 1966-February 15, 2012) using the search terms dabigatran, VTE, Afib, pharmacokinetics, pharmacodynamics, pharmacoeconomics, and cost-effectiveness. Citations from available articles were also reviewed for additional references.

RESULTS

For VTE prophylaxis, DE 150 or 220 mg orally daily has demonstrated either superiority or noninferiority to subcutaneous enoxaparin once daily in most studies. However, one study failed to demonstrate noninferiority to subcutaneous enoxaparin dosed BID in the composite end point of VTE, and all-cause mortality. For VTE treatment, DE 150 mg BID orally was shown to be noninferior to warfarin in preventing recurrent events. For AF, DE 150 mg BID orally is superior to warfarin in the prevention of thromboembolism, whereas 110 mg BID is noninferior to warfarin. Pharmacoeconomic analyses performed in the United Kingdom and Ireland found that DE can be cost-saving compared with enoxaparin in the prevention of VTE. Adverse effects of DE reported in clinical studies include dyspepsia (12%-13%) and bleeding (minor bleeding: 6%-22%).

CONCLUSIONS

DE exhibited a safety profile and efficacy comparable to enoxaparin for VTE prophylaxis; comparable safety profile and efficacy to warfarin for VTE treatment; and superiority (150 mg BID orally) in the prevention of stroke and systemic embolism compared with warfarin in patients with AF. The relative ease of oral administration, no need for routine monitoring, and lack of significant drug interactions, may favor use of DE over other anticoagulants. However, there is no antidote for DE currently available.

Pharmacoeconomics of dabigatran etexilate for prevention of thromboembolism after joint replacement surgery

Dabigatran etexilate (DE) is a novel oral anticoagulant indicated for the prevention of venous thromboembolism in patients undergoing total hip or total knee replacement surgery. The majority of these patients receive some kind of thromboprophylaxis, most commonly low-molecular-weight heparin (LMWH). However, the subcutaneous route of LMWH administration may act as a barrier to the continuation of effective anticoagulant prophylaxis after discharge from hospital. The oral route of DE administration may allow more patients to receive extended thromboprophylaxis and may reduce costs, such as those associated with nurse time for LMWH administrations, platelet monitoring, needlestick injuries and sharps disposal. This article presents an overview of the clinical evidence for DE and a systematic review of the economic evaluations of the drug.

Novel anticoagulants: a discussion of clinical use in the treatment and prevention of venous thromboembolism

Traditional therapeutic oral anticoagulation strategies often require invasive dosing or monitoring. Vitamin K antagonists (VKAs) have a large number of interactions, delayed onset requires frequent dose monitoring, and they have a small margin between therapeutic dose and bleeding complications. Novel oral anticoagulants, such as dabigatran, rivaroxaban and apixaban, are being developed to prevent those VKAs drawbacks. Besides oral bioavailability, those compounds are designed to require minimal to no monitoring and have a favourable safety profile. This review reports efficacy and safety data of these compounds throughout clinical development, as well as new approaches for oral pharmacological management of venous thromboembolism.

New options with dabigatran etexilate in anticoagulant therapy

Thrombosis, the localized clotting of blood, occurs in both the arterial and venous circulation, and has a major impact on health outcomes. The primary etiology of myocardial infarctions, and approximately 80% of strokes, is acute arterial thrombosis. In combination this represents the most common cause of death in the Western world, while the third leading cause of cardiovascular-associated death is venous thromboembolism. An understanding of the pathogenic changes in the vessel wall and the blood that result in thrombosis is crucial for developing safer and more effective antithrombotic drugs. Dabigatran etexilate belongs to a new class of direct thrombin inhibitors. Following oral administration, dabigatran reaches peak plasma concentrations within 2 hours, shows linear pharmacokinetics, and a limited (but important) amount of direct drug interactions. Given once daily at 150 mg or 220 mg, it has proven to be competitive with enoxaparin in the prevention of venous thromboembolism after major orthopedic surgery, with a comparable safety profile. For stroke prevention in patients suffering from atrial fibrillation, dabigatran administered at a dose of 110 mg twice daily was associated with rates of stroke and systemic embolism that were similar to those associated with warfarin, as well as lower rates of hemorrhage. Dabigatran given at a dose of 150 mg twice daily, as compared with warfarin, was associated with lower rates of stroke and systemic embolism but similar rates of major hemorrhage. Oral bioavailability of dabigatran, together with a rapid onset and offset of action and predictable anticoagulation response, makes this newly available antithrombotic drug an attractive alternative to traditional anticoagulant therapies for numerous thrombosis-related indications.