Rivaroxaban for the treatment of symptomatic deep-vein thrombosis and pulmonary embolism in Chinese patients: a subgroup analysis of the EINSTEIN DVT and PE studies

Efficacy and Safety of Rivaroxaban for Extremely Aged Patients with Venous Thromboembolism: A Retrospective, Cross-Sectional Real-World Study

Background

Rivaroxaban, a non-vitamin K antagonist oral anticoagulant, has become widely used for the management of venous thromboembolism (VTE) in adult patients. However, few trials have explored the efficacy and safety of rivaroxaban in VTE patients over 80 years of age. This necessitates further real-world studies of rivaroxaban across elderly populations.

Methods

We performed a retrospective single center study involving extremely aged VTE sufferers treated with rivaroxaban. The sample comprised 121 patients newly initiated on rivaroxaban diagnosed between January 2018 and January 2020. Patients were followed up for no less than 2 years. The effectiveness outcome was the disappearance of thromboembolism. The safety outcome was the incidence of major bleeding events. Comorbidities and complications were recorded throughout the entire study.

Results

The efficacy outcome occurred in 114 of 121 patients (94.21%) and the safety outcome occurred in 12 of 121 patients (9.91%). Increased hemorrhages were observed in patients with infection (15.15% vs 7.80%), but no significant difference was observed due to limited sample size (P=0.3053). Patients with an age-adjusted Charlson comorbidity index score higher than 6 points exhibited higher bleeding rates (14.08% vs 4.00%; P=0.0676) and lower thrombus cure rates (88.73% vs 100%; P=0.0203).

Key conclusions

Patients with infection should be more careful of bleeding events during rivaroxaban therapy. An age-adjusted Charlson comorbidity index score higher than 6, which predicted poor survival, indicated inferior safety and efficacy of rivaroxaban.

Aim

To investigate the efficacy and safety of Rivaroxaban in an aged venous thromboembolism patient population under real-world conditions.

Oral direct thrombin inhibitors or oral factor Xa inhibitors versus conventional anticoagulants for the treatment of pulmonary embolism

BACKGROUND

Pulmonary embolism (PE) is a potentially life-threatening condition in which a clot can migrate from the deep veins, most commonly in the leg, to the lungs. Conventional treatment of PE used unfractionated heparin (UFH), low molecular weight heparin (LMWH), fondaparinux, and vitamin K antagonists (VKAs). Recently, two forms of direct oral anticoagulants (DOACs) have been developed: oral direct thrombin inhibitors (DTIs) and oral factor Xa inhibitors. DOACs have characteristics that may be favourable to conventional treatment, including oral administration, a predictable effect, no need for frequent monitoring or re-dosing, and few known drug interactions. This review reports the efficacy and safety of these drugs in the long-term treatment of PE (minimum duration of three months). This is an update of a Cochrane Review first published in 2015.  OBJECTIVES: To assess the efficacy and safety of oral DTIs and oral factor Xa inhibitors versus conventional anticoagulants for the long-term treatment of PE.

SEARCH METHODS

The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase and CINAHL databases, the World Health Organization International Clinical Trials Registry Platform and the ClinicalTrials.gov trials registers to 2 March 2022. We checked the reference lists of relevant articles for additional studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) in which people with a PE confirmed by standard imaging techniques were allocated to receive an oral DTI or an oral factor Xa inhibitor compared with a conventional anticoagulant or compared with each other for the long-term treatment of PE (minimum duration three months).

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcomes were recurrent PE, recurrent venous thromboembolism (VTE), and deep vein thrombosis (DVT). Secondary outcomes were all-cause mortality, major bleeding, and health-related quality of life. We used GRADE to assess the certainty of evidence for each outcome.

MAIN RESULTS

We identified five additional RCTs with 1484 participants for this update. Together with the previously included trials, we have included ten RCTs with a total of 13,073 participants. Two studies investigated an oral DTI (dabigatran) and eight studies investigated oral factor Xa inhibitors (three rivaroxaban, three apixaban, and two edoxaban). The studies were of good methodological quality overall.  Meta-analysis showed no clear difference in the efficacy and safety of oral DTI compared with conventional anticoagulation in preventing recurrent PE (odds ratio (OR) 1.02, 95% confidence interval (CI) 0.50 to 2.04; 2 studies, 1602 participants; moderate-certainty evidence), recurrent VTE (OR 0.93, 95% CI 0.52 to 1.66; 2 studies, 1602 participants; moderate-certainty evidence), DVT (OR 0.79, 95% CI 0.29 to 2.13; 2 studies, 1602 participants; moderate-certainty evidence), and major bleeding (OR 0.50, 95% CI 0.15 to 1.68; 2 studies, 1527 participants; moderate-certainty evidence). We downgraded the certainty of evidence by one level for imprecision due to the low number of events. There was also no clear difference between the oral factor Xa inhibitors and conventional anticoagulation in the prevention of recurrent PE (OR 0.92, 95% CI 0.66 to 1.29; 3 studies, 8186 participants; moderate-certainty evidence), recurrent VTE (OR 0.83, 95% CI 0.66 to 1.03; 8 studies, 11,416 participants; moderate-certainty evidence), DVT (OR 0.77, 95% CI 0.48 to 1.25; 2 studies, 8151 participants; moderate-certainty evidence), all-cause mortality (OR 1.16, 95% CI 0.79 to 1.70; 1 study, 4817 participants; moderate-certainty evidence) and major bleeding (OR 0.71, 95% CI 0.36 to 1.41; 8 studies, 11,447 participants; low-certainty evidence); the heterogeneity for major bleeding was significant (I2 = 79%). We downgraded the certainty of the evidence to moderate and low because of imprecision due to the low number of events and inconsistency due to clinical heterogeneity. None of the included studies measured health-related quality of life.

AUTHORS' CONCLUSIONS

Available evidence shows there is probably little or no difference between DOACs and conventional anticoagulation in the prevention of recurrent PE, recurrent VTE, DVT, all-cause mortality, and major bleeding. The certainty of evidence was moderate or low. Future large clinical trials are required to identify if individual drugs differ in effectiveness and bleeding risk, and to explore effect differences in subgroups, including people with cancer and obesity.

Oral direct thrombin inhibitors or oral factor Xa inhibitors versus conventional anticoagulants for the treatment of deep vein thrombosis

BACKGROUND

Deep vein thrombosis (DVT) is a condition in which a clot forms in the deep veins, most commonly of the leg. It occurs in approximately one in 1000 people. If left untreated, the clot can travel up to the lungs and cause a potentially life-threatening pulmonary embolism (PE). Previously, a DVT was treated with the anticoagulants heparin and vitamin K antagonists. However, two forms of direct oral anticoagulants (DOACs) have been developed: oral direct thrombin inhibitors (DTIs) and oral factor Xa inhibitors, which have characteristics that may be favourable compared to conventional treatment, including oral administration, a predictable effect, lack of frequent monitoring or dose adjustment and few known drug interactions. DOACs are now commonly being used for treating DVT: recent guidelines recommended DOACs over conventional anticoagulants for both DVT and PE treatment. This Cochrane Review was first published in 2015. It was the first systematic review to measure the effectiveness and safety of these drugs in the treatment of DVT. This is an update of the 2015 review.  OBJECTIVES: To assess the effectiveness and safety of oral DTIs and oral factor Xa inhibitors versus conventional anticoagulants for the long-term treatment of DVT.

SEARCH METHODS

The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase and CINAHL databases and the World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers to 1 March 2022.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) in which people with a DVT, confirmed by standard imaging techniques, were allocated to receive an oral DTI or an oral factor Xa inhibitor compared with conventional anticoagulation or compared with each other for the treatment of DVT.  DATA COLLECTION AND ANALYSIS: We used standard Cochrane methods. Our primary outcomes were recurrent venous thromboembolism (VTE), recurrent DVT and PE. Secondary outcomes included all-cause mortality, major bleeding, post-thrombotic syndrome (PTS) and quality of life (QoL). We used GRADE to assess the certainty of evidence for each outcome.

MAIN RESULTS

We identified 10 new studies with 2950 participants for this update. In total, we included 21 RCTs involving 30,895 participants. Three studies investigated oral DTIs (two dabigatran and one ximelagatran), 17 investigated oral factor Xa inhibitors (eight rivaroxaban, five apixaban and four edoxaban) and one three-arm trial investigated both a DTI (dabigatran) and factor Xa inhibitor (rivaroxaban). Overall, the studies were of good methodological quality. Meta-analysis comparing DTIs to conventional anticoagulation showed no clear difference in the rate of recurrent VTE (odds ratio (OR) 1.17, 95% confidence interval (CI) 0.83 to 1.65; 3 studies, 5994 participants; moderate-certainty evidence), recurrent DVT (OR 1.11, 95% CI 0.74 to 1.66; 3 studies, 5994 participants; moderate-certainty evidence), fatal PE (OR 1.32, 95% CI 0.29 to 6.02; 3 studies, 5994 participants; moderate-certainty evidence), non-fatal PE (OR 1.29, 95% CI 0.64 to 2.59; 3 studies, 5994 participants; moderate-certainty evidence) or all-cause mortality (OR 0.66, 95% CI 0.41 to 1.08; 1 study, 2489 participants; moderate-certainty evidence). DTIs reduced the rate of major bleeding (OR 0.58, 95% CI 0.38 to 0.89; 3 studies, 5994 participants; high-certainty evidence).   For oral factor Xa inhibitors compared with conventional anticoagulation, meta-analysis demonstrated no clear difference in recurrent VTE (OR 0.85, 95% CI 0.71 to 1.01; 13 studies, 17,505 participants; moderate-certainty evidence), recurrent DVT (OR 0.70, 95% CI 0.49 to 1.01; 9 studies, 16,439 participants; moderate-certainty evidence), fatal PE (OR 1.18, 95% CI 0.69 to 2.02; 6 studies, 15,082 participants; moderate-certainty evidence), non-fatal PE (OR 0.93, 95% CI 0.68 to 1.27; 7 studies, 15,166 participants; moderate-certainty evidence) or all-cause mortality (OR 0.87, 95% CI 0.67 to 1.14; 9 studies, 10,770 participants; moderate-certainty evidence). Meta-analysis showed a reduced rate of major bleeding with oral factor Xa inhibitors compared with conventional anticoagulation (OR 0.63, 95% CI 0.45 to 0.89; 17 studies, 18,066 participants; high-certainty evidence).  AUTHORS' CONCLUSIONS: The current review suggests that DOACs may be superior to conventional therapy in terms of safety (major bleeding), and are probably equivalent in terms of efficacy. There is probably little or no difference between DOACs and conventional anticoagulation in the prevention of recurrent VTE, recurrent DVT, pulmonary embolism and all-cause mortality. DOACs reduced the rate of major bleeding compared to conventional anticoagulation. The certainty of evidence was moderate or high.

Anticoagulant-associated gastrointestinal bleeding: Framework for decisions about whether, when and how to resume anticoagulants

Gastrointestinal (GI) bleeding is the most frequent single site of oral anticoagulant (OAC)-associated major bleeding. Patients with major GI bleeding experience morbidity and a substantial risk of short-term all-cause mortality up to 10%. While OACs are frequently discontinued during acute bleeding, there is substantial uncertainty about whether, when, and how OACs should be resumed after bleeding has resolved. Limited evidence suggests a lower risk of thromboembolism and death, and a higher risk of recurrent bleeding with OAC resumption. However, the absolute risks and optimal timing of anticoagulation remain uncertain based on these observational studies at risk of bias, particularly due to baseline confounding. In addition to an individualized approach to determining the benefits and harms of treatment decisions informed by the best available evidence about thrombosis and recurrent bleeding, discussions should meaningfully incorporate patient values and preferences. The objective of this review is to provide a framework for decision-making by summarizing the epidemiology and clinical outcomes of OAC-associated GI bleeding, providing an approach for assessment and risk stratification for OAC resumption and its timing, and outlining strategies for the prevention of recurrent GI bleeding.

Safety and Efficacy of Rivaroxaban and Apixaban in Patients with Increased Body Mass: a Systematic Review

BACKGROUND AND OBJECTIVE

Rivaroxaban and apixaban are direct oral anticoagulants increasing in popularity as convenient alternatives to warfarin. However, current guidelines recommend against use in patients with a BMI > 40 kg/m² or bodyweight > 120 kg unless drug-specific levels are measured, which may not be feasible across all clinical practices. Accordingly, the objective of this study was to broadly examine literature evaluating the clinical outcomes of rivaroxaban and/or apixaban in patients with increased body mass.

METHODS

A systematic literature review (guided by PRISMA) was performed through January 27, 2021 using PubMed, Embase, and Scopus. Key search term clusters included drug and weight-related concepts (overweight/obese, body mass index [BMI], waist circumference). DistillerSR was utilized to review and process search results. Studies met inclusion if they analyzed the risk of bleeding and/or thrombosis in patients with increased body mass (i.e., via BMI or other criteria) receiving rivaroxaban or apixaban. Clinical guidelines, case reports/series, pharmacokinetic/dynamic analyses, and commentaries were excluded. Bias was examined qualitatively across studies.

RESULTS

After duplicates were removed, the original search rendered 1822 abstracts and 200 full-texts for screening, ultimately providing a final set of 24 studies for qualitative review. Of these studies, 13 (54.2%) enabled comparisons between patients of increased versus normal body mass, while 11 (45.8%) reported outcomes only for patients of increased body mass. The working definition of 'increased body mass' varied amongst the studies, including 11 (45.8%) studies that utilized BMI, seven (29.2%) with a combination of BMI and body measurement, two (8.3%) that relied on body weight alone, and four (16.7%) that identified obesity-related ICD codes. All 13 comparative studies found similar or reduced rates of safety and efficacy outcomes with rivaroxaban and apixaban.

CONCLUSION

The literature reports similar or lower bleeding and thrombotic risk for rivaroxaban and apixaban in patients of increased body mass compared to patients of normal body mass. Future prospective controlled studies are needed to further define guidelines for use in this population.

Rivaroxaban for the treatment of cerebral venous thrombosis

BACKGROUND

New Oral Anticoagulants (NOACs) such as Rivaroxaban are introduced as alternatives to conventional vitamin-K antagonists in the long-term treatment of thrombotic events due to their lower bleeding risk. There is a lack of evidence on the effectiveness and safety of Rivaroxaban in Cerebral venous thrombosis (CVT). This study aims to assess the effectiveness and bleeding risk of Rivaroxaban in comparison with Warfarin for the treatment of CVT.

MATERIALS AND METHODS

36 patients with diagnosis of CVT were included. Clinical and background information was assessed on admission and patients were followed for at least 12 months. Measured outcomes were modified Rankin Scale (mRS), evidence of recanalization on contrast-enhanced Brain MR venography (MRV) and major or minor bleeding. Patients were divided into two groups according to the type of oral anticoagulant (Rivaroxaban vs Warfarin). Groups were compared in terms of final outcomes and side effects.

RESULT

Overall, 13 (36.11%) patients received Warfarin and 23 (63.89%) received Rivaroxaban. Optimal mRS score (0-1) was attained in 9 of 10 (90%) of patients treated with Rivaroxaban and 19 of 22 (86.36%) of patients received Warfarin. MRV showed complete or partial recanalization in 12 of 14 (85.71%) patients treated with Rivaroxaban and all patients in the Warfarin group. There was no significant difference between the two groups in terms of major and minor hemorrhage.

CONCLUSION

Rivaroxaban holds promise for the treatment of CVT.

Ethnoracial variations in venous thrombosis: Implications for management, and a call to action

Despite decades of improvement in its diagnosis and management, venous thromboembolism (VTE) remains a significant cause of cardiovascular morbidity and mortality. Clinically relevant differences exist in the risk of symptomatic VTE among ethnoracial groups. Underlying these differences in rates of VTE are patterns of known genetic thrombophilias, which may also influence the risks of major bleeding related to vitamin K antagonists or direct oral anticoagulants. In addition, social factors, differential access to care, and disease awareness differ between ethnoracial groups, which contributes to disparities in VTE outcomes that include higher fatal events. The vast majority of participants included in clinical trials for the prevention and treatment of VTE have been White Caucasian, which limits our understanding of the differential impact of these agents in non-White ethnoracial groups. Increasing the participation in clinical trials of diverse ethnoracial groups should be a priority, especially those groups who are disproportionately affected by the burden of VTE, or possible bleeding complications when exposed to anticoagulants. Advocacy by patients, researchers, and regulatory bodies is crucial to ensure adequate enrolment of diverse ethnoracial groups in order to best inform clinical decisions to optimize VTE prevention and treatment for non-White populations.

Cost-effectiveness of rivaroxaban compared with enoxaparin plus warfarin for the treatment of hospitalised acute deep vein thrombosis in China

OBJECTIVE

Limited economic evaluation data for rivaroxaban compared with standard of care (SoC) exists in China. The objective of this analysis was to evaluate the cost-effectiveness of rivaroxaban compared with current SoC (enoxaparin overlapped with warfarin) for the treatment of acute deep vein thrombosis (DVT) in China.

METHODS

A Markov model was adapted from a payer's perspective to evaluate the costs and quality-adjusted life years (QALYs) of patients with DVT treated with rivaroxaban or enoxaparin/warfarin. Clinical data from the EINSTEIN-DVT trial were obtained to estimate the transition probabilities. Data on Chinese health resource use, unit costs and utility parameters were collected from previously published literature and used to estimate the total costs and QALYs. The time horizon was set at 5 years and a 3-month cycle length was used in the model. A 5% discount rate was applied to the projected costs. One-way sensitivity analyses and probabilistic sensitivity analyses were undertaken to assess the impact of uncertainty on results.

RESULTS

Rivaroxaban therapy resulted in an increase of 0.008 QALYs and was associated with lower total costs compared with enoxaparin/warfarin (US$4744.4 vs US$5572.4, respectively), demonstrating it to be a cost-saving treatment strategy. The results were mainly sensitive to length of hospitalisation due to DVT on enoxaparin/warfarin, cost per day of hospitalisation and the difference in length of stay of rivaroxaban-treated and enoxaparin/warfarin-treated patients.

CONCLUSION

Rivaroxaban therapy resulted in a cost saving compared with enoxaparin/warfarin for the anticoagulation treatment of patients with hospitalised acute DVT in China.

TRIAL REGISTRATION NUMBER

NCT00440193; Post-results.

Rivaroxaban treatment for young patients with pulmonary embolism (Review)

Pulmonary embolism (PE) is a serious, life-threatening condition that affects young populations (>18 and <50 years old, according to most literature reviews) with improved recognition of its clinical manifestations and the widespread use of sensitive imaging techniques, PE is increasingly diagnosed in younger patients. At present, there is limited understanding of the clinical features and adequate anticoagulant treatment options for this population. Most studies to date have yet to demonstrate significant differences in PE pathophysiology or symptoms between young and elderly patients. Although the overall incidence of PE is lower in young populations compared with elderly patients, important risk factors also apply for young patients. Hereditary thrombophilia is common and is a major cause of PE in younger patients. Immobilization, trauma, obesity, smoking and infection are also becoming increasingly frequent in young patients with PE. Among female patients, oral contraceptive use, pregnancy and postpartum status are predominant risk factors underlying PE. Rivaroxaban is a direct oral anticoagulant with a rapid onset of action that is associated with less drug-drug interactions compared with other therapies. Because the drug is administered at fixed doses with no requirement for routine coagulation monitoring, it is becoming an attractive option for anticoagulation treatment in young patients with PE. Therefore, the present literature review focuses on the clinical characteristics of PE and rivaroxaban therapy in younger patients.

Changing Treatment Patterns in Patients With Venous Thromboembolism in Taiwan

BACKGROUND

In Asia, little information is available about contemporary real-world treatment patterns for venous thromboembolism (VTE).Methods and Results:Consecutive patients (n=11,414) from the Taiwan National Health Insurance Research Database with initial VTE and taking oral anticoagulants between May 1, 2014 and June 30, 2016 were included. The temporal trends of using oral anticoagulants and pharmacomechanical therapy during the study period were evaluated. The efficacy and safety of nonvitamin K antagonist oral anticoagulants (NOACs) vs. warfarin were compared. Propensity score analysis (NOACs n=3,647 vs. warfarin n=3,647) was used to balance covariates between groups, and Cox proportional hazards models with adjustment were used to estimate the risks of clinical outcomes. The use of NOACs increased from 0.3% to 60.2% for VTE treatment during the study period. Pharmacomechanical therapy was used in 9.60%, 8.22%, and 5.63% from 2014 through 2016. NOACs were associated with a 16% risk reduction (adjusted hazard ratio [aHR] 0.84, 95% confidence interval [CI] 0.77-0.93) in all-cause mortality and a 21% risk reduction (aHR 0.79, 95% CI 0.65-0.96) in recurrent VTE vs. warfarin. Overall, NOACs were associated with a lower risk of major bleeding compared with warfarin (aHR 0.804, 95% CI 0.648-0.998).

CONCLUSIONS

In real-world practice, NOACs have become the major anticoagulant used for Asians with VTE. Although NOACs had a lower risk of recurrent VTE and major bleeding compared with warfarin in Taiwan, we still need a large-scale randomized controlled trial to confirm the findings.

Oral Rivaroxaban Versus Standard Therapy in Acute Venous Thromboembolism Treatment for Vietnamese Patients

BACKGROUND:

Direct oral anticoagulant-rivaroxaban may provide a simple, fixed-dose therapy for the management of hospital-acquired, acute venous thromboembolism (VTE) and for extended treatment, its use could skip lab observation and/or parenteral treatment.

AIM:

Compare the efficacy and safety (EAS) of RIV vs. standard therapy (SDTD) in a cohort of Vietnamese patients diagnosed with symptomatic, acute VTE.

METHODS:

An open-label, case-control, prospective study was conducted to check the efficacy and safety (EAS) of oral rivaroxaban (RIV) alone (15 mg 2 times/day for 3 weeks, then 20 mg 1 time/day) in a comparison to the standard therapy (STDT) (enoxaparin 1.0 mg/kg 2 times/day combining with vitamin K antagonist). Patients were treated for 6 months and followed-up for suspect reoccurring VTE and bleeding.

RESULTS:

A total 187 patients were enrolled into study. 83 were provided rivaroxaban and 104 received enoxaparin overlapping with vitamin K antagonist (VKAs). Recurrent VTE occurred in 3 (3.6%) rivaroxaban-received patients compared with 5 (4.8%) standard-treatment received patients (OR: 0.74, 95% CI, 0.17 to 3.20, p > 0.05). Major bleeding events were found in 1 (1,8%) and 4 (3.9%) cases in the RIV treated and STDT cohort, respectively (OR: 0.30, 95% CI, 0.03 to 2.76, p > 0.05).

CONCLUSION:

The finding of this study in Vietnamese patients with acute VTE presented comparable EAS profile with RIV versus STDT, consistent with those found in global population.

The Choice of Treatment Tactics for Thromboembolism of the Pulmonary Artery of Medium-High Risk and Chronic Kidney Disease

A clinical analysis of an elderly patient with medium-high-risk pulmonary thromboembolism and chronic kidney disease is presented. Recommendations on modern principles of diagnosis, choice of treatment tactics in patients with this pathology are given. Much attention is paid to the safety of anticoagulant treatment.

Direct Oral Anticoagulants and Travel-related Venous Thromboembolism

Travel- related thromboembolism reflects the relationship between venous thromboembolism (VTE) and long-haul flights. Although this condition is rare, it may cause significant morbidity and mortality. Therefore, travelers should be evaluated for the risks for thrombosis. Travel physicians should employ a clinical risk score and select in vestigations, prophylaxis, and treatment that are appropriate for each individual. This review summarizes current VTE clinical risk scores and patient management from various reliable guidelines. We summarized 16 reliable publications for reviewing data. Direct oral anticoagulants (DOACs) are currently the standard treatment for VTE and a prophylactic measure for VTE in orthopedic surgery. Compared with a vitamin K antagonist (VKA), DOACs show better safety and similar efficacy without the need for monitoring, and have fewer food/drug interactions. Inferred from the data on general VTE, DOACs may be used to treat travel-related VTE. Although the data are lacking, DOACs may be used off-label as VTE prophylax is. Before using DOACs, physicians must know the pharmacology of the drugs well and should realize that the availability of antidotes for bleeding complications is limited.

Influence of Renal Function on the Pharmacokinetics, Pharmacodynamics, Efficacy, and Safety of Non-Vitamin K Antagonist Oral Anticoagulants

With the growing integration of non-vitamin K antagonist oral anticoagulants (NOACs) into clinical practice, questions have arisen regarding their use in special populations, including groups that may have been underrepresented in clinical trials. Patients with renal impairment, particularly in the lower echelons of renal function, are one such group. In an effort to elucidate the current evidence regarding the use of NOACs in patients with renal impairment, a systematic assessment of the literature was performed. The MEDLINE database was interrogated for studies and analyses evaluating the influence of renal function on the pharmacokinetics, pharmacodynamics, efficacy, and safety of NOACs published from January 1, 2000, through August 2, 2017. The 82 relevant publications retrieved highlight the diversity in the NOAC class regarding the impact of renal function on drug clearance, drug exposures, and clinical trial outcomes. In several large clinical trials, subgroup analyses revealed no significant differences when patients were stratified by creatinine clearance as a measure of renal function. Efficacy findings, in particular, were largely aligned with the overall population in the included studies. However, relative risks of bleeding were shown to vary, sometimes driven by changes in bleeding event rates in the comparator arm (eg, warfarin, enoxaparin). With few exceptions, minimal influence of mild renal impairment was observed on the relative efficacy and safety of NOACs. Taken together, the evidence suggests that the presence of renal impairment merits careful consideration of anticoagulant choice but should not deter physicians from appropriate use of NOACs.

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.

Clinical outcomes during anticoagulant therapy in fragile patients with venous thromboembolism

BACKGROUND

Subgroup analyses from randomized trials suggested favorable results for the direct oral anticoagulants in fragile patients with venous thromboembolism (VTE). The frequency and natural history of fragile patients with VTE have not been studied yet.

OBJECTIVES

To compare the clinical characteristics, treatment and outcomes during the first 3 months of anticoagulation in fragile vs non-fragile patients with VTE.

METHODS

Retrospective study using consecutive patients enrolled in the RIETE (Registro Informatizado Enfermedad TromboEmbolica) registry. Fragile patients were defined as those having age ≥75 years, creatinine clearance (CrCl) levels ≤50 mL/min, and/or body weight ≤50 kg.

RESULTS

From January 2013 to October 2016, 15 079 patients were recruited. Of these, 6260 (42%) were fragile: 37% were aged ≥75 years, 20% had CrCl levels ≤50 mL/min, and 3.6% weighed ≤50 kg. During the first 3 months of anticoagulant therapy, fragile patients had a lower risk of VTE recurrences (0.78% vs 1.4%; adjusted odds ratio [OR]: 0.52; 95% confidence intervals [CI]: 0.37-0.74) and a higher risk of major bleeding (2.6% vs 1.4%; adjusted OR: 1.41; 95% CI: 1.10-1.80), gastrointestinal bleeding (0.86% vs 0.35%; adjusted OR: 1.84; 95% CI: 1.16-2.92), haematoma (0.51% vs 0.07%; adjusted OR: 5.05; 95% CI: 2.05-12.4), all-cause death (9.2% vs 3.5%; adjusted OR: 2.02; 95% CI: 1.75-2.33), or fatal PE (0.85% vs 0.35%; adjusted OR: 1.77; 95% CI: 1.10-2.85) than the non-fragile.

CONCLUSIONS

In real life, 42% of VTE patients were fragile. During anticoagulation, they had fewer VTE recurrences and more major bleeding events than the non-fragile.

Effect of rivaroxaban on preventing deep vein thrombosis in aged diabetics with femoral neck fractures after hip replacement

The present study estimates the effect of rivaroxaban on preventing deep vein thrombosis (DVT) in aged diabetics with femoral neck fractures after hip replacement. Our study consisted of 236 aged diabetics with femoral neck fractures, which were divided into the rivaroxaban and control groups. Reaction time (R time), clot formation time (K time), α angle (α), maximum amplitude (MA), clot elasticity (G) and coagulation index (CI), prothrombin time (PT) and activated partial thromboplastin time (APTT) were measured. DVT was diagnosed by color duplex Doppler ultrasound (CDDU). The risk factors of DVT were analysed by logistic regression analysis. Compared with the control group, in the rivaroxaban group, R time and K time were extended and α, MA and G decreased 1 day before operation. One day after operation, the rivaroxaban group had less PT and APPT and lower incidence of DVT than the control group. In the two groups, preoperative and postoperative PT and APPT significantly differed. Body mass index (BMI) ≥25, abnormal coagulation indicators, use of cemented femoral hip prosthesis, high haemoglobin content and non-ankle pump exercise after operation were the risk factors for DVT. Rivaroxaban could prevent DVT in aged diabetics with femoral neck fractures after hip replacement.

Management of Venous Thromboembolisms: Part I. The Consensus for Deep Vein Thrombosis

Deep vein thrombosis (DVT) is a potentially catastrophic condition because thrombosis, left untreated, can result in detrimental pulmonary embolism. Yet in the absence of thrombosis, anticoagulation increases the risk of bleeding. In the existing literature, knowledge about the epidemiology of DVT is primarily based on investigations among Caucasian populations. There has been little information available about the epidemiology of DVT in Taiwan, and it is generally believed that DVT is less common in Asian patients than in Caucasian patients. However, DVT is a multifactorial disease that represents the interaction between genetic and environmental factors, and the majority of patients with incident DVT have either inherited thrombophilia or acquired risk factors. Furthermore, DVT is often overlooked. Although symptomatic DVT commonly presents with lower extremity pain, swelling and tenderness, diagnosing DVT is a clinical challenge for physicians. Such a diagnosis of DVT requires a timely systematic assessment, including the use of the Wells score and a D-dimer test to exclude low-risk patients, and imaging modalities to confirm DVT. Compression ultrasound with high sensitivity and specificity is the front-line imaging modality in the diagnostic process for patients with suspected DVT in addition to conventional invasive contrast venography. Most patients require anticoagulation therapy, which typically consists of parenteral heparin bridged to a vitamin K antagonist, with variable duration. The development of non-vitamin K oral anticoagulants has revolutionized the landscape of venous thromboembolism treatment, with 4 agents available,including rivaroxaban, dabigatran, apixaban, and edoxaban. Presently, all 4 drugs have finished their large phase III clinical trial programs and come to the clinical uses in North America and Europe. It is encouraging to note that the published data to date regarding Asian patients indicates that such new therapies are safe and efficacious. Ultimately, our efforts to improve outcomes in patients with DVT rely on the awareness in the scientific and medical community regarding the importance of DVT.

KEY WORDS

Combination therapy; Hypertension; α1-blocker.

Oral direct thrombin inhibitors or oral factor Xa inhibitors for the treatment of pulmonary embolism

BACKGROUND

Pulmonary embolism is a potentially life-threatening condition in which a clot can travel from the deep veins, most commonly in the leg, up to the lungs. Previously, a pulmonary embolism was treated with the anticoagulants heparin and vitamin K antagonists. Recently, however, two forms of direct oral anticoagulants (DOACs) have been developed: oral direct thrombin inhibitors (DTI) and oral factor Xa inhibitors. The new drugs have characteristics that may be favourable over conventional treatment, including oral administration, a predictable effect, lack of frequent monitoring or re-dosing and few known drug interactions. To date, no Cochrane review has measured the effectiveness and safety of these drugs in the long-term treatment (minimum duration of three months) of pulmonary embolism.

OBJECTIVES

To assess the effectiveness of oral DTIs and oral factor Xa inhibitors for the long-term treatment of pulmonary embolism.

SEARCH METHODS

The Cochrane Vascular Trials Search Co-ordinator searched the Specialised Register (last searched January 2015) and the Cochrane Register of Studies (last searched January 2015). Clinical trials databases were also searched for details of ongoing or unpublished studies. We searched the reference lists of relevant articles retrieved by electronic searches for additional citations.

SELECTION CRITERIA

We included randomised controlled trials in which patients with a pulmonary embolism confirmed by standard imaging techniques were allocated to receive an oral DTI or an oral factor Xa inhibitor for the long-term (minimum duration three months) treatment of pulmonary embolism.

DATA COLLECTION AND ANALYSIS

Two review authors (LR, JM) independently extracted the data and assessed the risk of bias in the trials. Any disagreements were resolved by discussion with the third author (PK). We used meta-analyses when we considered heterogeneity low. The two primary outcomes were recurrent venous thromboembolism and pulmonary embolism. Other outcomes included all-cause mortality and major bleeding. We calculated all outcomes using an odds ratio (OR) with a 95% confidence interval (CI).

MAIN RESULTS

We included five randomised controlled trials with a total of 7897 participants. Two studies tested oral DTIs (dabigatran) and three studies tested oral factor Xa inhibitors (one rivaroxaban, one edoxaban and one apixaban).Analysis showed no difference in the effectiveness of oral DTIs and standard anticoagulation in preventing recurrent pulmonary embolism (OR 1.02, 95% CI 0.50 to 2.04; two studies; 1602 participants; high quality evidence), recurrent venous thromboembolism (OR 0.93, 95% CI 0.52 to 1.66; two studies; 1602 participants; high quality evidence), deep vein thrombosis (DVT) (OR 0.79, 95% CI 0.29 to 2.13; two studies; 1602 participants; high quality evidence) and major bleeding (OR 0.50, 95% CI 0.15 to 1.68; two studies; 1527 participants; high quality evidence).For oral factor Xa inhibitors, when we combined the three included studies together in meta-analyses, there was significant heterogeneity for recurrent pulmonary embolism (OR 1.08, 95% CI 0.46 to 2.56; two studies; 4509 participants; I(2) = 58%; moderate quality evidence). The oral factor Xa inhibitors were no more or less effective in the prevention of recurrent venous thromboembolism (OR 0.85, 95% CI 0.63 to 1.15; three studies; 6295 participants; high quality evidence), DVT (OR 0.72, 95% CI 0.39 to 1.32; two studies; 4509 participants; high quality evidence), all-cause mortality (OR 1.16, 95% CI 0.79 to 1.70; one study; 4817 participants; moderate quality evidence) or major bleeding (OR 0.97, 95% CI 0.59 to 1.62; two studies; 4507 participants; high quality evidence). None of the studies measured quality of life.

AUTHORS' CONCLUSIONS

Moderate to high quality evidence suggests that there are no differences between DOACs and standard anticoagulation for the long-term treatment of pulmonary embolism, for the outcomes recurrent pulmonary embolism, recurrent venous thromboembolism, DVT, all-cause mortality and major bleeding.

Shortened length of hospital stay with rivaroxaban in patients with symptomatic venous thromboembolism in Japan: the J-EINSTEIN pulmonary embolism and deep vein thrombosis program

BACKGROUND

In Japan, the standard of care for the treatment of pulmonary embolism (PE) and/or deep vein thrombosis (DVT) consists of intravenous unfractionated heparin (UFH) followed by warfarin, which was recently compared with rivaroxaban, an oral factor Xa inhibitor, in randomized trials.

AIM

To examine the length of hospital stay in patients with PE and/or DVT receiving rivaroxaban compared to Japanese standard therapy in the Japanese (J)-EINSTEIN PE and DVT program.

METHODS

Open-label, randomized clinical trials that compared 3, 6, or 12 months of rivaroxaban with UFH and warfarin in patients with acute, confirmed symptomatic proximal PE and/or DVT. Decisions regarding hospital admission and/or discharge were left to the clinical judgment of attending physicians. Analyses were conducted in the intention-to-treat (ITT) population.

RESULTS

In the ITT population (N = 97), overall patient characteristics were similar in both treatment arms. The median length of stay in rivaroxaban patients was 10.0 days (interquartile range [IQR] 6.0 to 15.0 days) while it was 15.0 days (IQR 9.0 to 22.0) for patients on standard therapy (p = 0.016). All of the four DVT patients who were not hospitalized for the index event were in the rivaroxaban arm.

CONCLUSIONS

Our results suggest that treatment with rivaroxaban may significantly reduce the length of hospital stay in patients hospitalized for PE and/or DVT compared with the current standard of care in Japan, thereby reducing the burden on patients and the healthcare system. The limitations of our study include small sample size and the generalizability of the findings to the real-world setting. Further research is warranted to identify PE and/or DVT patients in Japanese clinical practice who may potentially be managed as outpatients.

TRIAL REGISTRATION

Clinicaltrials.gov: NCT01516814 and NCT01516840.

Treating pulmonary embolism in Pacific Asia with direct oral anticoagulants

Pulmonary embolism (PE) is the principal preventable cause of in-hospital deaths. Prevalence of PE in Asians is uncertain but undoubtedly underestimated. Asians and Caucasians have similar non-genetic risk factors for PE, and there is mounting evidence that PE affects Asians much more commonly than previously supposed; incidence, especially among high-risk patients, may approach that in Caucasians. Furthermore, PE incidence in Asia is increasing, due to both increased ascertainment, and also population ageing and growing numbers of patients with predisposing risk factors. Despite being warranted, thromboprophylaxis for high-risk patients is not routine in Pacific Asian countries/regions. There also appears to be scope to implement venous thromboembolism (VTE) management guidelines more assiduously. Anticoagulants, primarily heparins and warfarin, have been the mainstays of VTE management for years; however, these agents have limitations that complicate routine use. The complexity of current guidelines has been another barrier to applying evidence-based recommendations in everyday practice. Updated management approaches have considerable potential to improve outcomes. New oral anticoagulants that are easier to administer, require no, or much less, monitoring or dose-adjustment and have a favourable risk/benefit profile compared with conventional modalities, may offer an alternative with the potential to simplify VTE management. However, more information is required on practical management and the occurrence and treatment of bleeding complications. Increasing recognition of the burden of PE and new therapeutic modalities are altering the VTE management landscape in Pacific Asia. Consequently, there is a need to further raise awareness and bridge gaps between the latest evidence and clinical practice.

Use of novel oral anticoagulants for the treatment of venous thromboembolism and its considerations in Asian patients

Parenteral anticoagulation followed by warfarin has been conventionally used for the treatment of venous thromboembolism (VTE). However, there are numerous troublesome characteristics of warfarin that prompted the development of novel oral anticoagulants (NOACs) for the treatment of VTE. Asians are reported to be at an increased risk of bleeding with warfarin, and while the reported incidence of VTE in Asians is lower than in Caucasians, the annual rate of VTE in Asia is rising along with the need for better oral anticoagulant options. Recently, several Phase III clinical trials with NOACs for the treatment and prevention of VTE recurrence have been published. For the treatment of VTE, the four NOACs - dabigatran, rivaroxaban, apixaban, and edoxaban - each showed comparable efficacy outcomes while resulting in better safety outcomes when compared with conventional treatment. In these trials, Asian patients had comparable efficacy and safety outcomes as other races, except in the edoxaban trial, in which the Asian subgroup had better safety profiles than other races, although further confirmation is necessary. For secondary prevention, dabigatran was compared with conventional treatment and showed similar efficacy and safety outcomes. When NOACs were compared with placebo for secondary prevention of VTE, they showed superior efficacy and increased bleeding except for apixaban, which showed comparable major bleeding and composite of major and clinically relevant nonmajor bleeding rates as placebo. No significant differences in the outcomes based on race were observed in the Asian subgroups for secondary prevention. Therefore, NOACs can be used with similar efficacy and at least similar or superior safety compared with conventional treatment in the treatment of VTE, and at no increased risk in Asian patients.