Extended use of dabigatran, warfarin, or placebo in venous thromboembolism

Strategies for the prevention and treatment of bleeding in patients treated with dabigatran: an update

INTRODUCTION

Although dabigatran is safer than vitamin K antagonists, bleeding still occurs. Bleeding is an important cause of short-term morbidity and rarely mortality and can also have long-term consequences that are often under-appreciated. After bleeding, patients often do not restart treatment or are poorly adherent, which is associated with increased thromboembolism and mortality. Consequently, we need strategies to prevent and treat bleeding in patients with atrial fibrillation treated with dabigatran.

AREAS COVERED

We review a) relevant dabigatran pharmacology, b) the burden and consequences of bleeding, c) how to identify patients at high risk of bleeding; and d) existing and novel approaches to prevent and treat bleeding in dabigatran-treated patients.

EXPERT OPINION

Concerns about the risk of bleeding associated with anticoagulant therapy and emerging evidence of increased risk of thromboembolism and mortality after bleeding highlight the need for improved approaches to prevention and treatment of bleeding. Future research priorities should focus on improving our ability to prevent bleeding by identifying modifiable risk factors and the development of safer agents. The current front runners include drugs that selectively target the contact pathway of coagulation (e.g. factor XI). Targeting upstream drivers of thrombosis (e.g. inflammation) could help to further reduce the risk of thromboembolism.

When and how to use direct oral anticoagulants in patients with advanced chronic liver disease?

Direct oral anticoagulants (DOACs) emerged as effective and safe alternatives to traditional anticoagulants for the prevention and treatment of venous thromboembolic disease and the prevention of stroke in non-valvular atrial fibrillation. Patients with advanced chronic liver disease (ACLD) have a higher risk of thromboembolism and bleeding than patients with normal liver function. Therefore, anticoagulation and, in particular, direct oral anticoagulants play a central role. Portal vein thrombosis is a relatively frequent complication in patients with ACLD, but its treatment remains challenging. DOACs have been introduced in clinical practice and demonstrated similar efficacy and safety profiles compared with vitamin K antagonist and heparins. However, further data about the use of DOACs in patients suffering from ACLD are needed. This review summarizes current knowledge in terms of anticoagulation in patients with ACLD and focuses on the available data about the use of DOACs in this population.

Medication guide for the perioperative management of oral antineoplastic agents in cancer patients

BACKGROUND

Oral antineoplastic agents (OAAs) are high-risk drugs that may increase the risk of bleeding, difficulty in wound healing, or produce alterations in coagulation and/or platelet aggregation. These aspects had to be highly considered throughout the entire perioperative process. Our aim was to create a comprehensive management medication guide based on reconciliation and dose adjustment recommendations for OAAs in patients undergoing a surgical intervention.

RESEARCH DESIGN AND METHODS

We analyzed all OAAs approved by the EMA in November 2020. We assessed data related to dose adjustment, drug reconciliation, coagulation disturbances, or anticoagulant interactions from the FDA and EMA summary of product characteristics.

RESULTS

We analyzed 67 OAAs. We identified that 51 (76.2%) OAAs can produce alteration in the platelet count, 12 (17.9%) affect the wound healing and recovery process, and 32 (47.8%) require control and monitoring in case of combination with anticoagulants. Only 13 (19.4%) OAAs, most of them antiangiogenics, have specific recommendations for temporary suspension before surgery.

CONCLUSIONS

Most OAAs require perioperative monitoring. This review can serve as an easy (simple, effective) tool to help healthcare professionals involved in patient care to manage OAAs during the perioperative process.

Venous thrombosis recurrence risk according to warfarin versus direct oral anticoagulants for the secondary prevention of venous thrombosis

BACKGROUND

Venous thromboembolism (VTE) affects nearly 1 million Americans annually, and many benefit from continued anticoagulation after the initial 3- to 6-month treatment period (secondary prevention).

OBJECTIVES

To determine whether warfarin, apixaban, or rivaroxaban is associated with reduced recurrent VTE hospitalization in the secondary prevention of VTE.

PATIENTS/METHODS

We performed a retrospective cohort study of participants enrolled in the MarketScan Insurance Database between 2013 and 2017 in those with an incident VTE. In those individuals who continued oral anticoagulation (warfarin, apixaban, or rivaroxaban) beyond 6 months, we determined the relative rate of recurrent VTE hospitalization.

RESULTS

Among 119 964 individuals with VTE, 25 419 remained on anticoagulation after 6 months and were matched successfully by age, sex, and date. After adjusting for a propensity score, apixaban versus rivaroxaban (hazard ratio [HR], 0.65; 95% confidence interval [CI], 0.45-0.94) and apixaban versus warfarin (HR, 0.68; 95% CI, 0.47-1.00) had a reduced risk of recurrent VTE hospitalization, and rivaroxaban versus warfarin (HR, 1.12; 95% CI, 0.94-1.33) had equivalent rates. For the rivaroxaban versus warfarin comparison there was a significant interaction by renal function (P < .01) where rivaroxaban was associated with a lower risk of recurrent VTE hospitalization (HR, 0.65; 95% CI, 0.41-1.03) in those with kidney disease and increased risk in those without kidney disease (HR, 1.24; 95% CI, 1.02-1.50).

CONCLUSIONS

These data suggest that apixaban has a lower recurrent VTE hospitalization rate than rivaroxaban during the secondary prevention of VTE, and further study of diverse patient populations, especially by kidney function, is warranted.

Diagnostic accuracy of D-Dimer testing for recurrent venous thromboembolism: A systematic review with meta-analysis.: VTE recurrence and D-dimer

OBJECTIVE

Venous thromboembolism (VTE) recurrence is a major concern after a first symptomatic episode, potentially impacting survival and healthcare needs in community, hospital and rehabilitation settings. We evaluated the association of D-Dimer positivity after oral anticoagulant therapy (OAT) discontinuation with VTE recurrence.

METHODS

PubMed, Web of Science, Scopus and EMBASE databases were systematically searched. Differences were expressed as Odds Ratio (OR) with 95% confidence intervals (95%CI). Pooled sensitivity, specificity, positive (PLR) and negative likelihood ratio (NLR), and summary ROC (sROC) curve were calculated.

RESULTS

Twenty-six articles on 10,725 VTE patients showed that the absolute risk of recurrence was 16.1% (95%CI: 13.2%-19.5%) among 4,049 patients with a positive D-Dimer and 7.4% (95%CI: 6.0%-9.0%) in 6,676 controls (OR: 2.1, 95%CI: 1.7-2.8, P<0.001), with an attributable risk of 54.0%. sROC curve of the association between positive D-Dimer and recurrence showed a diagnostic AUC of 63.8 (95%CI: 60.3-67.4), with a pooled sensitivity of 54.3% (95%CI: 51.3%-57.3%), specificity of 64.2% (95%CI: 63.2-65.1), PLR of 1.53 (95%CI: 1.37-1.72), and NLR of 0.71 (95%CI: 0.60-0.84). Subgroup and meta-regression analyses suggested that a positive D-Dimer may have a higher discriminatory ability for patients with provoked events, confirmed by better pooled diagnostic indexes for recurrence and a diagnostic AUC of 70.6 (95%CI: 63.8-77.4). Regression models showed that the rate of OAT resumption after the evidence of D-Dimer positivity was inversely associated with VTE recurrence (Z-score: -3.91, P<0.001).

CONCLUSIONS

D-Dimer positivity after OAT may identify VTE patients at higher risk of recurrence, with a better diagnostic accuracy for provoked events.

[Actual use of direct oral anticoagulants in venous thromboembolic disease]

Direct oral anticoagulants recently became the first-line choice for anticoagulation in venous thromboembolic disease. Many studies have shown its non-inferiority regarding the risk of thromboembolic recurrence compared to anti-vitamin K without increasing the risk of bleeding in the general population. However, specific populations such as patients with cancer, patients with kidney failure, patients with constitutional thrombophilia, elderly patients, or patients with extreme weight are at risk of intolerance to the use of direct oral anticoagulants. Precautions in use may be necessary as discussed in recently published guidelines about antiphospholipid syndrome. This review aims to list the main clinical trials investigating direct oral anticoagulants in venous thromboembolic disease in the general population and populations at risk, as well as to provide an update on current international and French guidelines.

Efficacy and safety of non-vitamin K antagonist oral anticoagulants for venous thromboembolism: a meta-analysis

Objective

Several trials had compared the efficacy and safety between non-vitamin K antagonist oral anticoagulants and warfarin for acute venous thromboembolism, but the results were incomplete. This updated review comprehensively assessed the efficacy and safety of non-vitamin K antagonist oral anticoagulants for venous thromboembolism.

Design

Meta-analysis of randomised control trials. Six databases were searched from January 2000 to December 2018.

Setting

Adult patients had got non-vitamin K antagonist oral anticoagulants or warfarin for venous thromboembolism.

Participants

Randomised control trials that compared the efficacy and safety between non-vitamin K antagonist oral anticoagulants and warfarin.

Main outcome measures

The efficacy and safety of non-vitamin K antagonist oral anticoagulants .

Results

Seven studies involving 29,879 cases were included, among which 14,943 cases were assigned to non-vitamin K antagonist oral anticoagulants group and 14,936 cases to warfarin group. Meta-analysis showed that compared with warfarin, recurrent venous thromboembolism (odds ratio 0.94 [95% confidence interval 0.81 to 1.11]), death related to venous thromboembolism or fatal pulmonary embolism (odds ratio 1.00 [95% confidence interval 0.63 to 1.60]), symptomatic deep-vein thrombosis (odds ratio 0.88 [95% confidence interval 0.72 to 1.09]), symptomatic nonfatal pulmonary embolism (odds ratio 1.03 [(95% confidence interval 0.82 to 1.30]) and all deaths (odds ratio 0.92 [95% confidence interval 0.76 to 1.12]) are similar in non-vitamin K antagonist oral anticoagulants group, but major bleeding event (odds ratio 0.61 [95% confidence interval 0.50 to 0.75]) and clinically relevant non-major bleeding event (odds ratio [95% confidence interval 0.53 to 0.85]) are less in non-vitamin K antagonist oral anticoagulants group. .

Conclusions

For the treatment of venous thromboembolism, non-vitamin K antagonist oral anticoagulants is as effective as warfarin, and has a better safety profile than warfarin.

Pathway for the Diagnosis and Management of Pulmonary Embolism

Venous thromboembolism (VTE), the combined syndromes of deep vein thrombosis (DVT) and pulmonary embolism (PE), is currently the third most frequent acute cardiovascular syndrome globally behind myocardial infarction and stroke. PE carries substantial mortality. In the past decade, we have seen a remarkable improvement in new diagnostic tools as well as advances in therapeutic options to manage patients with PE. Still, even with recently updated society guidelines, the management of intermediate and high-risk PE requires clinician expertise and judgment. To aid healthcare providers caring for patients with acute PE, we have developed a novel, comprehensive yet straightforward, pathway for the management of patients with PE. We believe this pathway can be used in many healthcare systems around the globe. Our pathway for the diagnosis and management of PE is divided into 3 steps: the diagnosis of PE, the acute management of patients with PE, and recommendations for chronic management. The pathway requires classification of the PE by the risk of mortality and thus leads to the appropriate intensity of initial care, intervention, and monitoring. The Pulmonary Embolism Response Team (PERT) is a multispecialty team designed to guide the decision-making for the individual patient with intermediate-high or high-risk PE. The PERT team brings together specialists from different disciplines. The team convenes in real time via a platform such as WhatsApp or text messages to communicate clinical data, discuss the options, and provide consensus for a course of management. The success of this pathway to manage PE depends heavily on developing a collaborative group of specialists dedicated to provide care at each stage to patients with PE.

Evaluation of Prescribing Practices and Outcomes Using Direct-acting Oral Anticoagulants After Cardiac Surgery

PURPOSE

Cardiac surgery patients frequently require anticoagulation. Warfarin remains the preferred agent, and a few trials have reported negative outcomes with the use of direct-acting oral anticoagulants (DOACs) in these patients. Therefore, limited literature exists that supports the dosing, safety, and efficacy of DOACs within the cardiac surgery population.

METHODS

This single-center, retrospective analysis was conducted at a tertiary academic medical center. All data were extrapolated from electronic medical records of qualifying patients from August 2017 to August 2019. Adult patients were included if they received at least 1 of 4 DOACs (apixaban, rivaroxaban, edoxaban, or dabigatran) after undergoing one of the following cardiac surgeries: coronary artery bypass graft, bioprosthetic valve replacement, aortic surgery, or valve repair. The composite safety end point included major bleeding and clinically relevant nonmajor bleeding, as defined by the International Society on Thrombosis and Hemostasis. The composite efficacy outcome of thromboembolic events included deep vein thrombosis, pulmonary embolism, ischemic stroke, and intracardiac thrombus.

FINDINGS

A total of 305 patient charts were identified for analysis; 229 patients met the inclusion criteria. The composite safety outcome occurred in 12 patients (5.2%) within 90 days after cardiac surgery. One patient (0.4%) experienced a thromboembolic event within 90 days after cardiac surgery. The most commonly prescribed DOAC was apixaban (79.0%). US Food and Drug Administration-approved dosing was used in 91.3% of patients, and DOACs were primarily used for the indication of stroke prevention in atrial fibrillation or atrial flutter (88.2%).

IMPLICATIONS

These data provide insight into the prescribing practices, efficacy, and safety of DOACs in cardiac surgery patients.

Fracture risks among patients with atrial fibrillation receiving different oral anticoagulants: a real-world nationwide cohort study

AIMS

To evaluate the fracture risk among patients with atrial fibrillation (AF) treated with non-vitamin K antagonist oral anticoagulants (NOACs) or warfarin.

METHODS AND RESULTS

We conducted a real-world nationwide retrospective cohort study using Taiwan's National Health Insurance Research Database. All adult patients in Taiwan newly diagnosed with AF between 2012 and 2016 who received NOACs or warfarin were enrolled and followed up until 2017. Patients treated with NOACs were sub-grouped according to the NOAC used (dabigatran, rivaroxaban, and apixaban). Propensity score matching was performed for each head-to-head comparison. Cox regression analysis, with a shared frailty model, was used to calculate the adjusted hazard ratios (aHRs) for hip, vertebral, and humerus/forearm/wrist fractures. After matching, 19 414 patients were included (9707 in each NOAC and warfarin groups). The median follow-up time was 2.4 years. Compared with warfarin, NOACs were associated with a reduced fracture risk [aHR = 0.84, 95% confidence interval (CI) = 0.77-0.93; P < 0.001]. Sub-analyses revealed that each NOAC, namely dabigatran (aHR = 0.88, 95% CI = 0.78-0.99; P = 0.027), rivaroxaban (aHR = 0.81, 95% CI = 0.72-0.90; P < 0.001), and apixaban (aHR = 0.67, 95% CI = 0.52-0.87; P = 0.003), had a reduced fracture risk. Analyses including all eligible patients, without propensity score matching, generated similar results.

CONCLUSION

Compared with warfarin, NOAC was associated with a reduced fracture risk among AF patients. Therefore, if oral anticoagulants are indicated, NOACs rather than warfarin should be considered to lower the risk of fractures. However, further studies are needed to investigate the underlying mechanisms and elucidate causality.

Antithrombotic therapy in the elderly and senile age: the consensus opinion of experts of the Russian Association of Gerontologists and Geriatricians and the National Society of Preventive Cardiology

В данном документе обсуждаются особенности АТТ у лиц пожилого и старческого возраста в различных клинических ситуациях.

Body Mass Index Influence on the Clinical Outcomes for Nonvalvular Atrial Fibrillation Patients Admitted to a Hospital Treated with Direct Oral Anticoagulants: A Retrospective Cohort Study

BACKGROUND

Considering that the current fixed dose of direct oral anticoagulants (DOACs) might have insufficient anticoagulation effect for overweight patients, the aim of this study was to compare the effectiveness and safety of anticoagulation between dabigatran and rivaroxaban in different body mass index (BMI) population.

METHODS

We conducted a retrospective cohort study of 2402 DOAC anticoagulated patients with atrial fibrillation who underwent catheter ablation (1290 dabigatran, 53.7% and 1112 rivaroxaban, 46.3%) between January 2017 and December 2018. Patients were distributed based on the BMI into nonobese (1362, BMI <25 kg/m2), preobese (521, BMI 25.0-29.9 kg/m2), class I obese (344, BMI 30.0-34.9 kg/m2) and class II+ obese (175, BMI ≥35.0 kg/m2). We collected information regarding clinical features, laboratory data, bleeding complications and systemic embolic events from the electrical medical records system during 12 months.

RESULTS

The incidence of systemic embolism and stroke complications was higher in the class II+ obese group (P=0.001 and P=0.003). The incidence of bleeding complications and the levels of anticoagulation parameters under the bleeding threshold were similar among the four groups (P>0.05). Cumulative Kaplan-Meier analysis illustrated that rivaroxaban-treated patients who belonged to higher BMI subgroups were more likely to experience shorter time to thrombosis (TTT) (12-month TTT rates of 0.5% for nonobese vs 1.7% for class I obese patients, HR=3.716, P=0.005; 12-month TTT rates of 0.5%, for nonobese vs 4.0% for class II+ obese patients, HR=6.843, P=0.001). However, no statistical significant difference in terms of the time to bleeding complications and the time to cumulative events among the four groups was observed. By multivariate analysis, a higher BMI value (BMI ≥25 kg/m2) (P=0.019; OR=2.094, 95%CI: 1.129-3.883) was an independent predictor for thrombosis in patients treated with dabigatran or rivaroxaban. Positive linear relationship was observed between BMI levels and occurrence rate of thrombosis and bleeding in under anticoagulation patients with NVAF (R2=0.451 and R2=0.383, respectively).

CONCLUSION

The fixed dose of 15 mg rivaroxaban might carry a risk of under exposure, which would lead to an increase of thromboembolic complications in patients with high BMI. Therefore, rivaroxaban dose increase was suggested for obese patients. Use of DOACs appears to have considerable safety in obese patients.

Impact of oral anticoagulant choice for the secondary prevention of venous thromboembolism on the risk of inpatient bleeding

Background

Randomized trials suggest that direct oral anticoagulants (DOACs) are at least as effective as warfarin for primary treatment of VTE and that bleeding risk may be lower for some DOACs relative to warfarin. However, there is very little information regarding potential bleeding risks for DOACs versus warfarin in secondary prevention of VTE.

Objective

The aim of this study was to compare rates of bleeding events resulting in inpatient admissions between individuals taking apixaban, rivaroxaban, and warfarin for secondary prevention of VTE during the period 2013-2017.

Methods

We used the IBM MarketScan Commercial Claims and Encounters Database and Medicare Supplemental and Coordination of Benefits Database (IBM Watson Health, Ann Arbor, MI) to establish a retrospective cohort. Initial venous thrombolism events were defined from medical claims, and follow-up for this cohort began 6 months after the initial event. Bleeding events resulting in inpatient admission were identified from claims data over the subsequent year of secondary prevention.

Results

A total of 69 264 individuals were identified for the cohort, with 567 bleeding events. The crude rate of bleeding was highest among warfarin users (1.47/100 person-years; 95% confidence interval [CI], 1.24-1.74) and lower among those on either apixaban (1.00/100 person-years; 95% CI, 0.65-1.54) or rivaroxaban (0.84/100 person-years; 95% CI, 0.66-1.08). In multivariable adjusted Cox models, those on apixaban (hazard ratio [HR], 0.80; 95% CI, 0.50-1.29) and rivaroxaban (HR, 0.81; 95% CI, 0.59-1.09) had somewhat lower rates of bleeding events relative to those on warfarin.

Conclusions

We found modest evidence of decreased risk of bleeding for apixaban and rivaroxaban. These estimates were relatively imprecise.

Pharmacokinetic modeling and simulation support for age- and weight-adjusted dosing of dabigatran etexilate in children with venous thromboembolism

BACKGROUND

Dabigatran etexilate (DE), a direct oral thrombin inhibitor, has been evaluated in children with venous thromboembolism (VTE) using oral solution, pellets, or capsules.

OBJECTIVES

This study evaluated DE pharmacokinetics (PK) in children with VTE and the appropriateness of a DE pediatric age- and weight-based dosing algorithm.

PATIENTS/METHODS

A population PK model was fitted to data from four single-arm and one randomized, comparative pediatric VTE studies (358 children aged birth to <18 years; 2748 PK observations) and one healthy-adult study (32 males aged <40 years; 1523 PK observations) using nonlinear mixed-effects modeling. A stepwise, covariate, model-building procedure evaluated the influence of covariates (e.g., age, body weight, body surface area [BSA]-normalized renal function, and sex). The final model was used to evaluate the pediatric dosing algorithm, with simulations comparing pediatric trough exposure with reference exposure defined for the pediatric studies.

RESULTS

The population PK of dabigatran was adequately described by a two-compartment model with first-order elimination and absorption. Age, weight, BSA-normalized renal function, and sex were statistically significant covariates (all P < .05). Apparent clearance increased with age (independently of body weight), diminished with decreasing BSA-normalized renal function, and was lower in females than males. All disposition parameters increased with body weight escalation (allometric scaling). Simulations confirmed that for all DE formulations, the final pediatric dosing algorithms achieved reference exposure without dose adjustment.

CONCLUSIONS

Using a population PK model of DE for children with VTE, simulations showed that the final dosing algorithms were appropriate for all DE formulations; no dose titration was needed.

Antithrombotics and new interventions for venous thromboembolism: Exploring possibilities beyond factor IIa and factor Xa inhibition

Direct oral anti-activated factor X and antithrombin agents have largely replaced vitamin K antagonists as the standard of care in treatment of venous thromboembolism. However, gaps in efficacy and safety persist, notably in end-stage renal disease, implantable heart valves or assist devices, extracorporeal support of the circulation, and antiphospholipid syndrome. Inhibition of coagulation factor XI (FXI) emerges as a promising new therapeutic target. Antisense oligonucleotides offer potential advantages as a prophylactic or therapeutic modality, with one dose-finding trial in orthopedic surgery already published. In addition, monoclonal antibodies blocking activation and/or activity of activated factor XI are investigated, as are small-molecule inhibitors with rapid offset of action. Further potential targets include upstream components of the contact pathway such as factor XII, polyphosphates, or kallikrein. Finally, catheter-directed, pharmacomechanical antithrombotic strategies have been developed for high- and intermediate-risk pulmonary embolism, and large randomized trials aiming to validate their efficacy, safety, and prognostic impact are about to start.

Comparative risk for intracranial hemorrhage related to new oral anticoagulants: A network meta-analysis

BACKGROUND

The intracranial hemorrhage (ICH) risk of oral anticoagulants/non-vitamin K antagonist oral anticoagulants (NOACs) remains largely unknown. Patients who need oral anticoagulants such as aspirin or warfarin often suffer from obvious complications.

METHODS

This network meta-analysis intended to assess the ICH risk in patients taking NOACs. The data from PubMed, the Cochrane database, and Embase were reviewed. All phase III randomized controlled trials of NOACs (apixaban, edoxaban, dabigatran, rivaroxaban), aspirin and warfarin were reviewed.

RESULTS

Twenty-three trials involving 137,713 participants were included, involving 6 regimens. Warfarin had the first risk of ICH (surface under the cumulative ranking area: 0.82), followed by dabigatran, edoxaban, aspirin, apixaban, rivaroxaban, and placebo. Dabigatran had the lowest risk of all-cause mortality (surface under the cumulative ranking area: 0.63), followed by apixaban, edoxaban, warfarin, rivaroxaban, aspirin, and placebo.

CONCLUSION

Warfarin significantly increased the risk of ICH in patients taking oral anticoagulants compared with 4 NOACs (dabigatran, edoxaban, apixaban, rivaroxaban) and aspirin. Apixaban is least likely to induce all-cause mortality.

Fracture Risks in Patients Treated With Different Oral Anticoagulants: A Systematic Review and Meta-Analysis

Background Evidence on the differences in fracture risk associated with non-vitamin K antagonist oral anticoagulants (NOAC) and warfarin is inconsistent and inconclusive. We conducted a systematic review and meta-analysis to assess the fracture risk associated with NOACs and warfarin. Methods and Results We searched PubMed, Embase, Cochrane Library, Scopus, Web of Science, and ClinicalTrials.gov from inception until May 19, 2020. We included studies presenting measurements (regardless of primary/secondary/tertiary/safety outcomes) for any fracture in both NOAC and warfarin users. Two or more reviewers independently screened relevant articles, extracted data, and performed quality assessments. Data were retrieved to synthesize the pooled relative risk (RR) of fractures associated with NOACs versus warfarin. Random-effects models were used for data synthesis. We included 29 studies (5 cohort studies and 24 randomized controlled trials) with 388 209 patients. Patients treated with NOACs had lower risks of fracture than those treated with warfarin (pooled RR, 0.84; 95% CI, 0.77-0.91; P<0.001) with low heterogeneity (I²=38.9%). NOACs were also associated with significantly lower risks of hip fracture than warfarin (pooled RR, 0.89; 95% CI, 0.81-0.98; P=0.023). A nonsignificant trend of lower vertebral fracture risk in NOAC users was also observed (pooled RR, 0.74; 95% CI, 0.54-1.01; P=0.061). Subgroup analyses for individual NOACs demonstrated that dabigatran, rivaroxaban, and apixaban were significantly associated with lower fracture risks. Furthermore, the data synthesis results from randomized controlled trials and real-world cohort studies were quite consistent, indicating the robustness of our findings. Conclusions Compared with warfarin, NOACs are associated with lower risks of bone fracture.

The risk of gastrointestinal hemorrhage with non-vitamin K antagonist oral anticoagulants: A network meta-analysis

BACKGROUND

Non-vitamin K antagonist oral anticoagulants (NOACs) have been widely used for stroke prevention in atrial fibrillation (AF) and the treatment and prevention of venous thromboembolism. There is an issue with safety, especially in clinically relevant bleeding. We performed a network meta-analysis to evaluate the risk of major gastrointestinal (GI) bleeding associated with NOACs.

METHODS

Interventions were warfarin, enoxaparin, apixaban, dabigatran, edoxaban, and rivaroxaban. The primary outcome was the incidence of major GI bleeding. A subgroup analysis was performed according to the following indications: AF, deep venous thrombosis/pulmonary embolism, and postsurgical prophylaxis.

RESULTS

A total of 29 randomized controlled trials (RCTs) and 4 large observation population studies were included. Compared with warfarin, apixaban showed a decreased the risk of major GI bleeding (relative risk [RR] 0.54, 95% confidence interval [CI] 0.25-0.76), and rivaroxaban tended to increase this risk (RR 1.40, 95% CI 1.06-1.85). Dabigatran (RR 1.25, 95% CI 0.98-1.60), edoxaban (RR 1.07, 95% CI 0.69-1.65), and enoxaparin (RR 1.24, 95% CI 0.63-2.43) did not significantly increase the risk of GI bleeding than did warfarin. In the subgroup analysis, according to indications, apixaban showed a decreased risk of major GI bleeding (RR 0.50, 95% CI 0.34-0.74) than did warfarin in AF studies. Dabigatran (RR 2.36, 95% CI 1.55-3.60, and rivaroxaban (RR 1.75, 95% CI 1.10-6.41) increased the risk of major GI bleeding than did apixaban. An analysis of studies on venous thromboembolism or pulmonary embolism showed that no individual NOAC or enoxaparin was associated with an increased risk of major GI bleeding compared to warfarin.

CONCLUSION

Individual NOACs had varying profiles of GI bleeding risk. Results of analyses including only RCTs and those including both RCTs and population studies showed similar trends, but also showed several differences.

Updates on Anticoagulation and Laboratory Tools for Therapy Monitoring of Heparin, Vitamin K Antagonists and Direct Oral Anticoagulants

Anticoagulant drugs have been used to prevent and treat thrombosis. However, they are associated with risk of hemorrhage. Therefore, prior to their clinical use, it is important to assess the risk of bleeding and thrombosis. In case of older anticoagulant drugs like heparin and warfarin, dose adjustment is required owing to narrow therapeutic ranges. The established monitoring methods for heparin and warfarin are activated partial thromboplastin time (APTT)/anti-Xa assay and prothrombin time – international normalized ratio (PT-INR), respectively. Since 2008, new generation anticoagulant drugs, called direct oral anticoagulants (DOACs), have been widely prescribed to prevent and treat several thromboembolic diseases. Although the use of DOACs without routine monitoring and frequent dose adjustment has been shown to be safe and effective, there may be clinical circumstances in specific patients when measurement of the anticoagulant effects of DOACs is required. Recently, anticoagulation therapy has received attention when treating patients with coronavirus disease 2019 (COVID-19). In this review, we discuss the mechanisms of anticoagulant drugs—heparin, warfarin, and DOACs and describe the methods used for the measurement of their effects. In addition, we discuss the latest findings on thrombosis mechanism in patients with COVID-19 with respect to biological chemistry.

Direct Oral Anticoagulant Use in Special Populations: Elderly, Obesity, and Renal Failure

PURPOSE OF REVIEW

The purpose of this review is to examine the safety and effectiveness of direct oral anticoagulants and provide recommendations for the treatment of venous thromboembolism and atrial fibrillation in obese patients, elderly patients, and patients with chronic kidney disease.

RECENT FINDINGS

Multiple retrospective cohort studies have shown no difference in bleeding, stroke, or venous thromboembolism outcomes between DOACs and warfarin in patients who are obese, elderly, or those with chronic kidney disease or on dialysis. Some studies have shown that DOACs have a lower bleeding risk than warfarin in these populations. DOACs may be a safe and effective alternative to warfarin for the prevention of stroke in atrial fibrillation patients who are obese, elderly, or those with chronic kidney disease or on dialysis. Apixaban may improve clinical outcomes by lowering the risk of bleeding versus warfarin. DOACs may also be an effective and safe alternative to warfarin for the treatment of venous thromboembolism in obese patients; however, additional studies are needed to assess their use in elderly patients and those with CKD.

Decision-Making in the Management of Venous Thromboembolism

Venous thromboembolism comprising deep venous thrombosis and pulmonary embolus is common. Patients with venous thromboembolism may present to a variety of health care providers, and while a significant proportion of patients begin treatment in the hospital, ambulatory management of both deep venous thrombosis and pulmonary embolus is feasible and becoming more common. Initial anticoagulant management, investigation of venous thromboembolism etiology, and decisions about extended anticoagulation require coordinated care by physicians from multiple specialties. Comprehensive management of venous thromboembolism requires coordinated care from the time of presentation in order to expedite diagnosis, initiate timely anticoagulant treatment, determine the need for extended anticoagulation based on risk of bleeding and recurrent thrombosis, and advise on thromboprophylaxis during future high-risk periods for venous thromboembolism. In this review we use case scenarios to provide an operational framework, based on current evidence-based recommendations, for informed decision-making about a number of clinical practice issues that are frequently encountered in the management of venous thromboembolism patients.

American Society of Hematology 2021 guidelines for management of venous thromboembolism: prevention and treatment in patients with cancer

BACKGROUND

Venous thromboembolism (VTE) is a common complication among patients with cancer. Patients with cancer and VTE are at a markedly increased risk for morbidity and mortality.

OBJECTIVE

These evidence-based guidelines of the American Society of Hematology (ASH) are intended to support patients, clinicians, and other health care professionals in their decisions about the prevention and treatment of VTE in patients with cancer.

METHODS

ASH formed a multidisciplinary guideline panel balanced to minimize potential bias from conflicts of interest. The guideline development process was supported by updated or new systematic evidence reviews. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach was used to assess evidence and make recommendations.

RESULTS

Recommendations address mechanical and pharmacological prophylaxis in hospitalized medical patients with cancer, those undergoing a surgical procedure, and ambulatory patients receiving cancer chemotherapy. The recommendations also address the use of anticoagulation for the initial, short-term, and long-term treatment of VTE in patients with cancer.

CONCLUSIONS

Strong recommendations include not using thromboprophylaxis in ambulatory patients receiving cancer chemotherapy at low risk of VTE and to use low-molecular-weight heparin (LMWH) for initial treatment of VTE in patients with cancer. Conditional recommendations include using thromboprophylaxis in hospitalized medical patients with cancer, LMWH or fondaparinux for surgical patients with cancer, LMWH or direct oral anticoagulants (DOAC) in ambulatory patients with cancer receiving systemic therapy at high risk of VTE and LMWH or DOAC for initial treatment of VTE, DOAC for the short-term treatment of VTE, and LMWH or DOAC for the long-term treatment of VTE in patients with cancer.

Advances in the Management of Acute Venous Thromboembolism and New Therapeutic Agents

Important advances in the understanding and management of venous thromboembolism (VTE) have enhanced our ability to diagnose, prevent, and treat VTE. In this narrative review, we discuss how recent advances in the understanding and management of VTE are changing practice, highlight ongoing unmet needs in VTE management, and outline how novel therapeutic targets with little or no influence on hemostasis may help address these unmet needs.

Risk of intracranial hemorrhage with direct oral anticoagulants: a systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

We performed a systematic review and meta-analysis to compare the risk of intracranial hemorrhage (ICH) between direct oral anticoagulants (DOACs) and other antithrombotic drugs in detail across all diseases.

METHODS

PubMed, EMBASE, Web of Science, and the Cochrane Library were searched for relevant randomized controlled trials (RCTs). Heterogeneity was examined using the I² statistic. Risk ratio (RR) and 95% confidence interval (CI) were calculated using random-effects meta-analysis.

RESULTS

Fifty-five RCTs were included in this meta-analysis. Compared with vitamin K antagonists (VKAs), dabigatran reduced the risk of ICH by 60% (RR 0.40; 95% CI 0.28-0.57), apixaban by 57% (RR 0.43; 95% CI 0.31-0.58), edoxaban by 56% (RR 0.44; 95% CI 0.29-0.67) and rivaroxaban by 41% (RR 0.59; 95%CI 0.44-0.80). Compared with low-molecular-weight heparins (LMWHs), apixaban, edoxaban and rivaroxaban had a similar risk of ICH. Compared with aspirin, dabigatran and apixaban had a similar risk of ICH, while rivaroxaban posed an increased risk of ICH (RR 2.12; 95% CI 1.31-3.44). For secondary prevention stroke, DOACs reduced the risk of ICH by 46% compared with warfarin (RR 0.54; 95% CI [0.42-0.70]) and had a similar risk of ICH compared with aspirin.

CONCLUSION

All DOACs had a lower risk of ICH than VKAs. In terms of the risk of ICH, DOACs were overall as safe as LMWHs, and apixaban and dabigatran were as safe as aspirin, but rivaroxaban was not. For secondary prevention stroke, the risk of ICH with DOACs was overall lower than warfarin and similar to aspirin, but it should be noted that compared with aspirin, rivaroxaban may increase the risk of ICH. This is the first pair-wise meta-analysis that compares the risk of ICH between DOACs and other antithrombotic drugs in detail across all diseases, which may have certain significance for patients with high risk of ICH to choose antithrombotic drugs in clinical practice.

Antithrombotic Management of Venous Thromboembolism: JACC Focus Seminar

Venous thromboembolism (VTE) is a significant public health burden. Management of anticoagulation is the mainstay of treatment for the vast majority of patients. The introduction of 4 direct oral anticoagulants beginning in 2010 has significantly affected selection of anticoagulants for patients with VTE. Treatment of VTE consists of 3 phases: the initial treatment (first 5 to 21 days), primary treatment (first 3 to 6 months), and secondary prevention (after the initial 3 to 6 months). Oral-only anticoagulation strategies are now available, using apixaban or rivaroxaban therapy, beginning in the initial treatment phase. In addition, low-dose anticoagulation with either apixaban or rivaroxaban can be used in the secondary prevention phase for appropriate patients. Use of the direct oral anticoagulants is now supported for many patients with cancer-associated VTE. Appropriate selection and monitoring of anticoagulants remains a critical element of high-quality care for patients with VTE.

Direct oral anticoagulants for unusual-site venous thromboembolism

Direct oral anticoagulants (DOACs) are currently the preferred oral anticoagulant treatment for most of the patients with deep vein thrombosis of the lower extremities and/or pulmonary embolism. DOACs have several advantages over vitamin K antagonists, such as availability of fixed dosages, fewer drug interactions, faster onset of action, shorter half-life, and lower risk of major and intracranial bleeding. Although the evidence on the use of DOACs in patients with unusual-site venous thromboembolism (VTE) is limited to a few, small randomized controlled trials, these drugs are increasingly used in clinical practice, and several observational cohort studies have been published recently. This narrative review will describe the latest evidence for the use of the DOACs in patients with thrombosis in atypical locations (splanchnic, cerebral, upper extremity, ovarian, and renal vein thrombosis) and will provide some practical advice for their use in patients with unusual-site VTE.

Lower dose direct oral anticoagulants and improved survival: A combined analysis in patients with established atherosclerosis

BACKGROUND

Antithrombotic/anticoagulation effects of direct oral anticoagulants (DOACs) are dose-dependent. However, recent observations suggest that administering lower dose DOACs may better protect against all-cause mortality. We investigated whether, in patients with established atherosclerosis, DOAC dose selection would affect the risk of all-cause mortality.

METHODS

We performed a structured literature research for controlled trials allowing random assignment to a lower dose DOAC, a higher dose DOAC, or control therapy in patients with established atherosclerosis. Pooled risk ratios (RRs) of all-cause mortality in lower and higher dose DOACs versus control therapy were estimated using a random-effect model.

RESULTS

Atherosclerosis manifested as acute coronary syndrome (n=17,220), stable coronary (CAD) and/or peripheral artery disease (PAD) (n=27,395) or CAD associated with atrial fibrillation (n=4,510). Antithrombotic doses of rivaroxaban (2.5 mg or 5.0 mg BID) or dabigatran (50 mg, 75 mg, 110 mg, or 150 mg, BID) were tested in three trials versus single or dual antiplatelet control therapy, whereas anticoagulation doses of edoxaban (30 mg or 60 OD) were tested versus warfarin in one trial. Compared to control, patients receiving lower dose (RR 0.80, 95% CI 0.73-0.89, p<0.0001, I²=0%), but not those receiving higher dose DOACs (RR 0.95, 95% CI 0.87-1.05, p=0.3074, I²=0%), had a significant reduction of all-cause mortality. Benefit from lower dose DOACs remained after sensitivity analysis or direct comparison with higher dose DOACs (RR 0.84, 95% CI 0.76-0.93, p=0.0009, I²=0%).

CONCLUSIONS

Within antithrombotic/anticoagulation regimens of DOAC administration, selection of lower dose appears to protect from all-cause mortality in patients with established atherosclerosis.

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.

Edoxaban for the Long-Term Therapy of Venous Thromboembolism: Should the Criteria for Dose Reduction be Revised?

Edoxaban is used for venous thromboembolism (VTE) treatment. Real-life data are lacking about its use in long-term therapy. We aimed to assess the efficacy and the safety of edoxaban for long-term VTE treatment in a real-life setting. Patients with VTE included in the Registro Informatizado Enfermedad TromboEmbólica (RIETE) registry, receiving edoxaban 60 or 30 mg daily were prospectively followed up to validate the benefit of using different dosages. The main outcome was the composite of VTE recurrences or major bleeding in patients with or without criteria for dose reduction. Multivariable analysis to identify predictors for the composite outcome was performed. From October 2015 to November 2019, 562 patients received edoxaban for long-term therapy. Most (94%) of the 416 patients not meeting criteria for dose reduction received 60 mg daily, and 92 patients meeting criteria (63%) received 30 mg daily. During treatment, two patients developed recurrent VTE, six had major bleeding and nine died (2 from fatal bleeding). Among patients not meeting criteria for dose reduction, those receiving 30 mg daily had a higher rate of the composite event (hazard ratio (HR) 8.37; 95% confidence interval (CI) 1.12-42.4) and a significant higher mortality rate (HR 31.1; 95% CI 4.63-262) than those receiving 60 mg. Among patients meeting criteria for dose reduction, those receiving 60 mg daily had no events, and a nonsignificantly higher mortality rate (HR 5.04; 95% CI 0.54-133) than those receiving 30 mg daily. In conclusion, edoxaban seems to be effective and safe for long-term VTE treatment in real life. Criteria for dose reduction should be reformulated.

Anticoagulation for Patients with Venous Thromboembolism: When is Extended Treatment Required?

The need for extended venous thromboembolism (VTE) treatment beyond 3 to 6 months is usually determined by balancing the risk of recurrence if treatment is stopped against the risk of bleeding from continuing treatment. The risk of recurrence, and in turn the decision to extend, can be determined through the nature of the index event. Patients with VTE provoked by surgery or trauma (major transient risk factors) are recommended to receive 3 months of anticoagulation therapy because their risk of recurrence is low, whereas patients with VTE provoked by a major persistent risk factor, such as cancer, or those considered to have “unprovoked” VTE, are recommended to receive an extended duration of therapy based on an established high risk of recurrence. Nonetheless, recent evidence and new guidance identify that this approach fails to consider patients with risk factors classed as minor transient (e.g., impaired mobility and pregnancy) or minor persistent (e.g., inflammatory bowel disease and congestive heart disease). Indeed, the risk of recurrence with respect to VTE provoked by minor persistent risk factors has been demonstrated to be not dissimilar to that of VTE without identifiable risk factors. This review provides an overview of the available data on the risk of recurrence according to the underlying cause of VTE, a critical evaluation of evidence from clinical studies on the available anticoagulants for extended VTE treatment, models of risk prediction for recurrent VTE and bleeding, and guidance on how to apply the evidence in practice.

Dabigatran etexilate for the treatment of acute venous thromboembolism in children (DIVERSITY): a randomised, controlled, open-label, phase 2b/3, non-inferiority trial

BACKGROUND

Dabigatran etexilate is a direct oral anticoagulant with potential to overcome the limitations of standard of care in children with venous thromboembolism. The aims of this clinical trial were to study the appropriateness of a paediatric dabigatran dosing algorithm, and the efficacy and safety of dabigatran dosed according to that algorithm versus standard of care in treating children with venous thromboembolism.

METHODS

DIVERSITY is a randomised, controlled, open-label, parallel-group, phase 2b/3 non-inferiority trial done in 65 centres in 26 countries. Standard of care (low-molecular-weight heparins, unfractionated heparin, vitamin K antagonists or fondaparinux) was compared with a paediatric oral dabigatran dosing regimen (an age-adjusted and weight-adjusted nomogram) in children younger than 18 years with acute venous thromboembolism initially treated (5-21 days) with parenteral anticoagulation, requiring anticoagulation therapy for at least 3 months. Patients were randomised 1:2 (standard of care:dabigatran) and stratified by age (12 to <18 years, 2 to <12 years, and birth to <2 years) via interactive response technology. The primary composite efficacy endpoint (intention-to-treat analysis) was the proportion of children with complete thrombus resolution, and freedom from recurrent venous thromboembolism and venous thromboembolism-related death. A non-inferiority margin of absolute differences of 20% was used. Secondary endpoints included safety (determined by major bleeding events [time-to-event analysis on the treated set]), and pharmacokinetic-pharmacodynamic relationships (descriptive analyses). This trial is registered with ClinicalTrials.gov, NCT01895777 and is completed.

FINDINGS

328 children were enrolled between Feb 18, 2014, and Nov 14, 2019. 267 were randomly assigned (90 [34%] to standard of care and 177 [66%] to dabigatran) and included in the analyses. Median exposure to standard of care was 85·0 days (IQR 80·0-90·0) and to dabigatran was 84·5 days (78·0-89·0). Similar proportions of children treated with standard of care and dabigatran met the composite efficacy endpoint (38 [42%] of 90 vs 81 [46%] of 177; Mantel-Haenszel weighted difference, -0·04; 90% CI -0·14 to 0·07; p<0·0001 for non-inferiority). On-treatment bleeding events were reported in 22 (24%) of 90 children receiving standard of care and 38 (22%) of 176 children receiving dabigatran (hazard ratio [HR] 1·15, 95% CI 0·68 to 1·94; p=0·61); major bleeding events were similar between the groups (two [2%] of 90 and four [2%] of 176; HR 0·94, 95% CI 0·17 to 5·16; p=0·95). Pharmacokinetic-pharmacodynamic curves showed a linear relationship between total dabigatran plasma concentration and diluted thrombin time and ecarin clotting time, and a non-linear relationship with activated partial thromboplastin time; curves were similar to those for adults. Serious adverse events were reported for 18 (20%) of 90 children receiving standard of care and 22 (13%) of 176 children receiving dabigatran. The most common severe adverse events were vascular disorders (standard of care three [3%] of 90, dabigatran two [1%] of 176), and gastrointestinal disorders (standard of care two [2%] of 90 and dabigatran five [3%] of 176). One on-treatment death occurred in the standard of care group (retroperitoneal bleeding, not considered treatment related by the study investigators).

INTERPRETATION

An age-adjusted and weight-adjusted dabigatran dosing algorithm was appropriate in children aged birth to less than 18 years with venous thromboembolism. Dabigatran was non-inferior to standard of care in terms of efficacy, with similar pharmacokinetic-pharmacodynamic relationships as those seen in adults, and might be a suitable alternative to standard of care.

FUNDING

Boehringer Ingelheim.

Using oral anticoagulants among chronic kidney disease patients to prevent recurrent venous thromboembolism: A systematic review and meta-analysis

INTRODUCTION

Chronic kidney disease (CKD) increases the risk of venous thromboembolism (VTE) among affected patients. Vitamin K antagonists (VKA) and warfarin remains the main stay of its treatment. Due to novelty and unclear risk-to-benefit ratio of direct oral anti-coagulants (DOAC), they remain underutilized in preventing VTE among CKD patients. We aim to assess the efficacy and safety of DOACs and other oral anticoagulants in preventing recurrent VTE among high-risk population.

MATERIAL METHODS

We conducted a literature search using PubMed, Embase, Cochrane, Web of Science and Clinicaltrials.gov for randomized controlled trials (RCTs) comparing anti-coagulants like DOAC, LMWH or VKA or any oral anti-coagulant (OAC) (This includes VKAs and DOACs) with either placebo or another anti-coagulant. Two independent reviewers screened the retrieved articles and extracted data using a piloted data extraction sheet. The primary outcome of interest was number of recurrent VTE and other side effects among CKD patients receiving respective treatment. Secondary outcomes were risk of major, non-major and intra-cranial bleed.

RESULTS

We retrieved 7244 titles on initial search, reviewed full text of 818 articles, and selected 10 phase III RCTS for quantitative meta-analysis. Out of 36,326 patients in these trials, only 10,840 (29.8%) were evaluable. We stratified patients into four categories based on severity of renal impairment using serum creatinine clearance (SCr) as the marker e.g. mild (>50 - <80) moderate (>30 - ≤50) severe (<30) and any level (from <30 to <80). There was no difference between DOACs vs VKA in decreasing the risk of recurrent VTE among patients with mild (RR:0.86, 95% CI:0.61-1.22, I² = 25%) moderate/severe (RR:0.72, 95% CI:0.44-1.17, I² = 0%) or any level of renal impairment (RR:0.83, 95% CI:0.60-1.14, I² = 34%). No difference in efficacy between LMWH vs VKA among patients with moderate (RR:2.40, 95% CI:0.44-12.96, I² = 76%) and any level (RR:2.59, 95% CI:0.66-10.16, I² = 71%) of renal impairment respectively. Similarly, no difference in efficacy between LMWH vs any OAC (This includes VKAs and edoxaban) among patients with (RR:2.16, 95% CI:0.66-7.-06, I² = 51%) and any level (RR:1.48, 95% CI:0.79-2.78, I² = 78%) of renal impairment. DOACs compared to VKAs had significantly lower risk of combined major and non-major bleeding (RR: 0.74, 95% CI:0.65-0.84, I² = 26%), major bleeding (RR: 0.51, 95% CI:0.38-0.69, I² = 7%) and non-major clinically relevant bleeding (RR: 0.73, 95% CI:0.57-0.94, I² = 45%) respectively. Risk of intracranial bleeding was comparable (RR: 0.68, 95% CI:0.19-2.44, I² = 0%). There was no difference in the risk of major bleeding between LMWH vs any OAC (RR: 0.83, 95% CI:0.46-1.51, I² = 0%).

CONCLUSION

DOACS and other anticoagulants (VKA and LMWH) showed no statistical difference in preventing recurrent VTEs among CKD patients but DOACs had significantly lower risk of major and non-major clinically relevant bleeding irrespective of the level of renal impairment compared to VKAs. There was no difference in risk of intra-cranial bleeding between DOACs and VKAs.

Direct oral anticoagulants: evidence and unresolved issues

Currently licenced direct oral anticoagulants selectively target thrombin (eg, dabigatran) or coagulation factor Xa (eg, apixaban, betrixaban, edoxaban, and rivaroxaban). Designed to be given in fixed doses without routine monitoring, direct oral anticoagulants have a lower propensity for food and drug interactions than do vitamin K antagonists, and in randomised controlled trials involving around 250 000 patients, they were at least as effective for prevention and treatment of thrombosis and were associated with a lower risk of life-threatening bleeding. The absolute benefits of direct oral anticoagulants over vitamin K antagonists are modest; however, guidelines recommend them in preference to vitamin K antagonists for most indications because of their ease of use and superior safety. The greatest benefits of direct oral anticoagulants are likely to be in patients who were previously deemed unsuitable for vitamin K antagonist therapy. The emergence of generic preparations is expected to further increase the uptake of direct oral anticoagulants, particularly in countries where they are currently not widely used because of cost. Direct oral anticoagulants are contraindicated in patients with mechanical heart valves and should be used with caution or avoided in patients with advanced kidney or liver disease. In this Therapeutics paper, we review the pharmacology of direct oral anticoagulants, summarise the evidence that led to their approval and incorporation into treatment guidelines, and explore key unresolved issues. We also briefly discuss future perspectives for the development of oral anticoagulants.

Direct oral anticoagulants for the treatment and prevention of venous thromboembolism in patients with cancer: current evidence

Venous thromboembolic disease (VTED) is a common and clinically important complication in patients with cancer, contributing to its mortality and morbidity. Direct oral anticoagulant agents (DOACs), including direct thrombin inhibitors and direct factor Xa inhibitors, are as effective as vitamin K antagonists for the treatment of VTED and are associated with less frequent and severe bleeding. They have advantages over low-molecular-weight heparin, but comparative long-term efficacy and safety data are lacking for these compounds. Recent randomized clinical trials suggest a role for DOACs in the treatment of VTED in patients with cancer. This review will discuss the existing evidence and future perspectives on the role of DOACs in the treatment of VTE based on the current evidence about their overall efficacy and safety and the limited information in patients with cancer; in addition, we will briefly review their pharmacokinetic properties with special reference to potential interactions.

Direct oral anticoagulants in antiphospholipid syndrome: Meta-analysis of randomized controlled trials

BACKGROUND

The gold standard for secondary thromboprophylaxis in APS is long term anticoagulation with vitamin K antagonists (VKAs). Because of their widespread use and potential advantages of directs oral anticoagulants (DOACs) over VKAs, they have been prescribed in APS without definitive evidence of their safety and efficacy in this context. Recent specific randomized controlled trials (RCT) in APS and results from pivotal RCTs comparing DOACs vs VKAs are now available. Their results are conflicting but these studies have been conducted in different APS populations.

PURPOSE OF REVIEW

To summarize available data from RCT and determine risks of recurrent thrombosis and bleeding.

RESULTS

Four studies were included and 23 and 10 thrombotic events were recorded among 282 and 294 APS patients treated with DOACs and warfarin respectively. Overall recurrent thrombotic events were not significantly increased during DOACs treatment (OR = 2.22 [95% CI, 0.58-8.43]) compared to VKAs. However, when different types of thrombosis were analyzed separately, there was an increased risk of recurrent arterial thrombosis (5.17 [95% CI, 1.57-17.04]) with DOACs compared to warfarin but no significant higher risk of venous thrombosis (OR 0.69 [95% CI, 0.23-2.06). No increased risk of bleeding was found.

IN CONCLUSION

In APS patients treated with DOACs compared to those treated with warfarin, no evidence of a higher risk of recurrent venous thromboembolism was found however there was a significantly increased risk of recurrent arterial thrombosis. Moreover risk of recurrent arterial thrombosis tended to be more frequent in patients with a history of arterial thrombosis. These results are in line with international guidelines which recommend not to use DOACs in APS patients with a history of arterial thrombosis but raise the question of the efficacy of DOACs to prevent venous thrombosis in a subset of APS patients without a history of arterial thrombosis.

Discovery of Benzyl Tetraphosphonate Derivative as Inhibitor of Human Factor Xia

The inhibition of factor XIa (FXIa) is a trending paradigm for the development of new generations of anticoagulants without a substantial risk of bleeding. In this report, we present the discovery of a benzyl tetra-phosphonate derivative as a potent and selective inhibitor of human FXIa. Biochemical screening of four phosphonate/phosphate derivatives has led to the identification of the molecule that inhibited human FXIa with an IC50 value of ∼7.4 μM and a submaximal efficacy of ∼68 %. The inhibitor was at least 14-fold more selective to FXIa over thrombin, factor IXa, factor Xa, and factor XIIIa. It also inhibited FXIa-mediated activation of factor IX and prolonged the activated partial thromboplastin time of human plasma. In Michaelis-Menten kinetics experiment, inhibitor 1 reduced the VMAX of FXIa hydrolysis of a chromogenic substrate without significantly affecting its KM suggesting an allosteric mechanism of inhibition. The inhibitor also disrupted the formation of FXIa - antithrombin complex and inhibited thrombin-mediated and factor XIIa-mediated formation of FXIa from its zymogen factor XI. Inhibitor 1 has been proposed to bind to or near the heparin/polyphosphate-binding site in the catalytic domain of FXIa. Overall, inhibitor 1 is the first benzyl tetraphosphonate small molecule that allosterically inhibits human FXIa, blocks its physiological function, and prevents its zymogen activation by other clotting factors under in vitro conditions. Thus, we put forward benzyl tetra-phosphonate 1 as a novel lead inhibitor of human FXIa to guide future efforts in the development of allosteric anticoagulants.

Wild P, H. Prochaska J. Telemedicine-Based Specialized Care Improves the Outcome of Anticoagulated Individuals with Venous Thromboembolism-Results from the thrombEVAL Study

Venous thromboembolism (VTE) is a life-threatening disease with risk of recurrence. Oral anticoagulation (OAC) with vitamin K antagonists (VKA) is effective to prevent thromboembolic recurrence. We aimed to investigate the quality of OAC of VTE patients in regular medical care (RMC) compared to a telemedicine-based coagulation service (CS). The thrombEVAL study (NCT01809015) is a prospective, multi-center study to investigate OAC treatment (recruitment: January 2011-March 2013). Patients were evaluated using clinical visits, computer-assisted personal interviews, self-reported data and laboratory measurements according to standard operating procedures. Overall, 360 patients with VTE from RMC and 254 from CS were included. Time in therapeutic range (TTR) was higher in CS compared to RMC (76.9% (interquartile range [IQR] 63.2-87.1%) vs. 69.5% (52.3-85.6%), p < 0.001). Crude rate of thromboembolic events (rate ratio [RR] 11.33 (95% confidence interval [CI] 1.85-465.26), p = 0.0015), clinically relevant bleeding (RR 6.80 (2.52-25.76), p < 0.001), hospitalizations (RR 2.54 (1.94-3.39), p < 0.001) and mortality under OAC (RR 5.89 (2.40-18.75), p < 0.001) were consistently higher in RMC compared with CS. Patients in RMC had higher risk for primary outcome (clinically relevant bleedings, thromboembolic events and mortality, hazard ratio [HR] 5.39 (95%CI 2.81-10.33), p < 0.0001), mortality (HR 5.54 (2.22-13.84), p = 0.00025), thromboembolic events (HR 6.41 (1.51-27.24), p = 0.012), clinically relevant bleeding (HR 5.31 (1.89-14.89), p = 0.0015) and hospitalization (HR 1.84 (1.34-2.55), p = 0.0002). Benefits of CS care were still observed after adjusting for comorbidities and TTR. In conclusion, anticoagulation quality and outcome of VTE patients undergoing VKA treatment was significantly better in CS than in RMC. Patients treated in CS had lower rates of adverse events, hospitalizations and lower mortality. CS was prognostically relevant, beyond providing advantages of improved international ratio (INR) monitoring.

American Society of Hematology 2020 guidelines for management of venous thromboembolism: treatment of deep vein thrombosis and pulmonary embolism

BACKGROUND

Venous thromboembolism (VTE), which includes deep vein thrombosis (DVT) and pulmonary embolism (PE), occurs in ∼1 to 2 individuals per 1000 each year, corresponding to ∼300 000 to 600 000 events in the United States annually.

OBJECTIVE

These evidence-based guidelines from the American Society of Hematology (ASH) intend to support patients, clinicians, and others in decisions about treatment of VTE.

METHODS

ASH formed a multidisciplinary guideline panel balanced to minimize potential bias from conflicts of interest. The McMaster University GRADE Centre supported the guideline development process, including updating or performing systematic evidence reviews. The panel prioritized clinical questions and outcomes according to their importance for clinicians and adult patients. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to assess evidence and make recommendations, which were subject to public comment.

RESULTS

The panel agreed on 28 recommendations for the initial management of VTE, primary treatment, secondary prevention, and treatment of recurrent VTE events.

CONCLUSIONS

Strong recommendations include the use of thrombolytic therapy for patients with PE and hemodynamic compromise, use of an international normalized ratio (INR) range of 2.0 to 3.0 over a lower INR range for patients with VTE who use a vitamin K antagonist (VKA) for secondary prevention, and use of indefinite anticoagulation for patients with recurrent unprovoked VTE. Conditional recommendations include the preference for home treatment over hospital-based treatment for uncomplicated DVT and PE at low risk for complications and a preference for direct oral anticoagulants over VKA for primary treatment of VTE.

Recent advances in understanding, diagnosing and treating venous thrombosis

Focusing on the current state of the art, this article (a) describes recent advances in the understanding of the pathogenesis of venous thromboembolism (VTE), (b) discusses current approaches for the prevention, diagnosis and treatment of VTE, (c) outlines the role of aspirin for VTE prevention and treatment, and (d) highlights the unmet needs in VTE management and describes novel approaches to address them.

Management of antithrombotic therapy in gray areas of venous thromboembolism: a Delphi consensus panel

For some years now, direct-acting oral anticoagulants (DOACs) have entered the clinical practice for stroke prevention in non-valvular atrial fibrillation (NVAF) or for prevention and treatment of venous thromboembolism (VTE). However, there is uncertainty on DOACs' use in some clinical scenarios that are not fully explored by clinical trials, but commonly encountered in the real world. We report a Delphi Consensus on DOAC use in VTE patients. The consensus dealt with seven main topics: (1) clinical superiority of DOACs compared to VKAs; (2) therapeutic options for patients with intermediate risk PE; (3) therapeutic management of patients with deep vein thrombosis (DVT); (4) DOACs' role in oncological patients with VTE; (5) role of the reversal agent; (6) safety of low doses of DOACs in VTE patients; (7) DOACs long-term therapy (more than 12 months) in VTE patients; Forty-six physicians (cardiologists, internists, angiologists, oncologists, hematologists, and geriatricians) from Italy expressed their level of agreement on each statement by using a five-point Likert scale (1: strongly disagree, 2: disagree, 3: somewhat agree, 4: agree, 5: strongly agree). Votes 1-2 were considered as disagreement, while votes 3-5 as agreement. For each statement an agreement of ≥ 66% among the respondents was considered consensus. A brief discussion about the results for each topic is also reported.

A comprehensive appraisal of dabigatran etexilate clinical evidence and applications: a 10-year-long story

During the last decade, non-vitamin K antagonist oral anticoagulants (NOACs) revolutionized the thromboprophylaxis management of several medical conditions, including atrial fibrillation and venous thromboembolism. Dabigatran etexilate was the first NOAC widely available worldwide, and it is currently the only one that directly inhibits thrombin. More recently, the availability of idarucizumab, a specific reversal agent, has increased the safety of dabigatran use in clinical practice, especially for those patients with severe and life-threatening bleeding. This review aims to summarize current evidence on dabigatran, starting from its pharmacological characteristics, and providing an updated overview of pivotal randomized controlled trials and real-world data on its efficacy and safety.

Clinical Trial Based Rationale for the Successful Use of DOAC in the Treatment of Cerebral Venous Sinus Thrombosis (CVST): A Case Report

In cerebral venous sinus thrombosis (CVST), venous sinus occlusion increases venous pressure and disrupts venous return, resulting in progression to venous infarction and venous hemorrhage, with poor neurologic outcome. Therefore, early recanalization of the major venous sinus is critical. Anticoagulant therapy with continuous intravenous infusion of heparin and subsequent oral anticoagulant administration is the recommended first line of treatment for CVST. Some large clinical trials for venous thromboembolism (VTE) have shown that direct oral anticoagulant (DOAC) is non-inferior to the standard therapy with heparin or warfarin and causes less bleeding. In contrast, there are only a few reports on CVST treatment with DOAC such as Dabigatran, Rivaroxaban and Edoxaban describing good efficacy and safety. And there is one randomized clinical trial on DOAC treatment for CVST after acute phase. We report a successfully treated case of CVST in acute phase with progressive neurologic symptoms that achieved early recanalization of the obstructed sinus by an early switch from continuous intravenous infusion of heparin to oral Edoxaban.