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

Anticoagulation in older people with atrial fibrillation moving to care homes: a data linkage study

BACKGROUND

Treatment decisions about oral anticoagulants (OACs) for atrial fibrillation (AF) are complex in older care home residents.

AIM

To explore factors associated with OAC prescription.

DESIGN AND SETTING

Retrospective cohort study set in care homes in Wales, UK, listed in the Care Inspectorate Wales Registry 2017/18.

METHOD

Analysis of anonymised individual-level electronic health and administrative data was carried out on people aged ≥65 years entering a care home between 1 January 2003 and 31 December 2018, provisioned from the Secure Anonymised Information Linkage Databank.

RESULTS

Between 2003 and 2018, 14 493 people with AF aged ≥65 years became new residents in care homes in Wales and 7057 (48.7%) were prescribed OACs (32.7% in 2003 compared with 72.7% in 2018) within 6 months before care home entry. Increasing age and prescription of antiplatelet therapy were associated with lower odds of OAC prescription (adjusted odds ratio [aOR] 0.96 per 1-year age increase, 95% confidence interval [CI] = 0.95 to 0.96 and aOR 0.91, 95% CI = 0.84 to 0.98, respectively). Conversely, prior venous thromboembolism (aOR 4.06, 95% CI = 3.17 to 5.20), advancing frailty (mild: aOR 4.61, 95% CI = 3.95 to 5.38; moderate: aOR 6.69, 95% CI = 5.74 to 7.80; and severe: aOR 8.42, 95% CI = 7.16 to 9.90), and year of care home entry from 2011 onwards (aOR 1.91, 95% CI = 1.76 to 2.06) were associated with higher odds of an OAC prescription.

CONCLUSION

There has been an increase in OAC prescribing in older people newly admitted to care homes with AF. This study provides an insight into the factors influencing OAC prescribing in this population.

Risk and Management of Bleeding Complications with Direct Oral Anticoagulants in Patients with Atrial Fibrillation and Venous Thromboembolism: a Narrative Review

Atrial fibrillation (AF) and venous thromboembolism (VTE) are highly prevalent conditions with a significant healthcare burden, and represent the main indications for anticoagulation. Direct oral anticoagulants (DOACs) are the first choice treatment of AF/VTE, and have become the most prescribed class of anticoagulants globally, overtaking vitamin K antagonists (VKAs). Compared to VKAs, DOACs have a similar or better efficacy/safety profile, with reduced risk of intracerebral hemorrhage (ICH), while the risk of major bleeding and other bleeding harms may vary depending on the type of DOAC. We have critically reviewed available evidence from randomized controlled trials and observational studies regarding the risk of bleeding complications of DOACs compared to VKAs in patients with AF and VTE. Special patient populations (e.g., elderly, extreme body weights, chronic kidney disease) have specifically been addressed. Management of bleeding complications and possible resumption of anticoagulation, in particular after ICH and gastrointestinal bleeding, are also discussed. Finally, some suggestions are provided to choose the optimal DOAC to minimize adverse events according to individual patient characteristics and bleeding risk.

Antithrombotic therapy for secondary prevention of unprovoked venous thromboembolism: a systematic review and network meta-analysis of randomized controlled trials

BACKGROUND

Extended antithrombotic treatment is recommended for secondary prevention of unprovoked venous thromboembolism (VTE), however, there is no consensus on which antithrombotic strategy is preferable.

AIM

To compare the efficacy and safety of different antithrombotic strategies for secondary prevention unprovoked VTE.

METHODS

Cochrane Central Register of Controlled Trials, Embase, and MEDLINE were systematically searched from inception to 22 July 2020 for randomized controlled trials (RCTs) that compared the efficacy and/or safety of extended antithrombotic strategies including aspirin, warfarin and direct oral anticoagulants (DOACs) for secondary prevention of unprovoked VTE. The primary outcome was risk of major bleeding and the secondary outcomes were risks of recurrent VTE and all-cause death. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using pairwise and network meta-analysis with random effect. Possible ranking of extended antithrombotic strategies was plotted using the surface under the cumulative ranking curve and mean ranks.

RESULTS

Seventeen RCTs met the inclusion criteria, and meta-analysis results showed that warfarin was associated with significantly higher risk of major bleeding than placebo/observation (OR 2.71, 95% CI 1.32-5.55) or apixaban (OR 10.65, 95% CI 1.06-107.13). Apixaban and low-apixaban were the top two strategies according to the ranking of major bleeding. Warfarin (OR 0.25, 95%CI 0.13-0.49), rivaroxaban (OR 0.18, 95%CI 0.03-0.90), apixaban (OR 0.18, 95%CI 0.04-0.85) and low-apixaban (OR 0.18, 95%CI 0.04-0.82) were related to significantly lower risk than placebo/observation; edoxaban was non-inferior to warfarin on the risk of recurrent VTE. Furthermore, apixaban was linked with significantly lower risk of all-cause death than placebo/observation (OR 0.29, 95% CI 0.09-0.88).

CONCLUSION

Apixaban showed superiority to other antithrombotic strategies on major bleeding and all-cause death for secondary prevention of unprovoked VTE. Further studies are warranted owing to the limited number of studies and positive cases.Key messagesAll antithrombotic strategies including warfarin, DOACs and aspirin were superior to placebo/observation on recurrent VTE for secondary prevention of unprovoked VTE.Apixaban demonstrated lower risk of major bleeding than warfarin, and lower risk of all-cause death than placebo/observation.Further research about the efficacy and safety of antithrombotic treatments for secondary prevention of unprovoked VTE is warranted.

Clinical and Safety Outcomes Associated with Extended Treatment of Venous Thromboembolism: A Network Meta-Analysis

BACKGROUND

Many anticoagulant strategies are available for the extended treatment of venous thromboembolism, yet little guidance exists regarding which drug is most effective and safe.

AIM

A network meta-analysis was performed to resolve this uncertainty.

METHODS

We searched the medical literature through June 2022 for randomized controlled trials (RCTs) evaluating the efficacy and safety of anticoagulants for adults with VTE compared with other anticoagulants or a placebo.

RESULTS

We identified 13 eligible RCTs in 12 articles. All pooled hazard ratios (HR) and 95% credible intervals (CrI) mentioned below, except that for aspirin, were calculated by comparison with standard-intensity warfarin. Novel oral anticoagulants (NOACs) were not inferior to standard-intensity warfarin in preventing recurrence, and edoxaban was ranked first among the NOACs (HR, 0.99; 95% CrI, 0.70-1.39). All the NOACs, except rivaroxaban, were superior to standard-intensity warfarin in preventing bleeding events. Apixaban was ranked first and was considered to be safer than other NOACs for control of both major bleeding (HR = 0.07, 95% CrI: 0.01-0.37) and clinically relevant non-major bleeding (CRNMB, HR = 0.30, 95% CrI: 0.13-0.67). Edoxaban was ranked second among the NOACs for control of major bleeding (HR = 0.44, 95% CI: 0.21-0.88), and dabigatran was ranked second among the NOACs for control of CRNMB (HR = 0.54, 95% CrI: 0.4-0.73).

CONCLUSIONS

There existed no statistically significant differences in recurrence between NOACs and standard-intensity warfarin, and NOACs were associated with a lower risk of bleeding events. Edoxaban effectively prevented VTE recurrence and major bleeding, and apixaban was the best anticoagulant for controlling bleeding events.

["Guiding lights" for the diagnosis of chronic thromboembolic pulmonary hypertension in the flow of patients with pulmonary embolism]

On December 13, 2021, an expert council was held to determine the position of experts of different specialties regarding the reasons for the low level of diagnosis of chronic thromboembolic pulmonary hypertension (CTEPH) in real clinical practice in a pandemic of a new coronavirus infection and possible ways to improve detection in patients with pulmonary embolism (PE) ) in history. The reasons for the low level of diagnosis of CTEPH are the insufficient level of knowledge of specialists, especially primary care physicians; lack of clear regulatory documents and expert centers for the management of this category of patients. Primary diagnosis of CTEPH in a pandemic can be strengthened through the widespread use of telemedicine for consultations of primary care physicians with specialists from expert centers; to maximize the role of echocardiography and computed tomography (CT) as differential diagnostic tools for dyspnea, in particular in patients with COVID-19. To increase the detection rate of CTEPH, diagnostic vigilance is required in patients with risk factors and episodes of venous thromboembolism. To improve the screening of CTEPH, it is necessary to create an algorithm for monitoring patients who have had PE; provide educational activities, including through the media; create materials for patients with accessible information. The regulatory documents should designate the circle of responsible specialists who will be engaged in long-term monitoring of patients with PE. Educational programs are needed for primary care physicians, cardiologists, and other physicians who come into the field of view of patients with CTEPH; introduction of a program to create expert centers for monitoring and managing patients with the possibility of performing ventilation-perfusion lung scintigraphy, cardiopulmonary stress test, CT, right heart catheterization. It seems important to build cooperation with the Ministry of Health of Russia in order to create special protocols, procedures for managing patients with PE and CTEPH.

Gastrointestinal Bleeding on Oral Anticoagulation: What is Currently Known

Gastrointestinal bleeding (GIB) is the most common type of bleeding occurring in patients on oral anticoagulation. A meta-analysis of the landmark randomized controlled trials (RCTs) for patients with atrial fibrillation demonstrated that direct oral anticoagulants (DOACs) were associated with higher GIB rates compared to warfarin. However, significant heterogeneity existed between studies. While rivaroxaban, high-dose dabigatran, and high-dose edoxaban were associated with higher GIB rates than warfarin, GIB rates were similar between warfarin users and both apixaban and low-dose dabigatran users. Additionally, previous observational studies have yielded conflicting reports on whether GIB rates differ between warfarin and DOACs. Meta-analyses of observational studies demonstrated that warfarin is associated with lower rates of GIB compared to rivaroxaban, similar or lower rates compared to dabigatran, and higher rates compared to apixaban. Importantly, no RCT has compared individual DOACs directly and due to the different selection criteria of the initial RCTs, indirect comparisons between DOACs using these studies are unreliable. The best available information of comparisons between individual DOACs is therefore limited to observational studies. There is mounting evidence that suggests that rivaroxaban is associated with a higher risk of GIB compared to other DOACs. Finally, GIB induced by oral anticoagulation may have some positive aspects. Interestingly, there are studies that indicate oral anticoagulation facilitates colorectal cancer detection. Furthermore, results from RCTs and observational studies suggest that warfarin may even decrease the incidence of cancer.

Direct Oral Anticoagulants for the Prevention and Acute Treatment of Cancer-Associated Thrombosis

Cancer is a major risk factor for venous thromboembolism (VTE), and cancer-associated thrombosis (CAT) constitutes approximately 15-25% of all VTE cases. For decades, the standard treatment for CAT used to be daily subcutaneous low molecular weight heparin (LMWH). Data on the safety and efficacy of the direct oral anticoagulants (DOACs) in this population emerged only in recent years and specific DOACs were included into recent guidelines recommendations. In this narrative review of the literature, we reported the results of the phase III randomized controlled trials that evaluated the DOACs for the prevention and the acute treatment of CAT. For the acute phase treatment, the anti-Xa inhibitors (apixaban, edoxaban, rivaroxaban) showed better efficacy than LMWH in preventing VTE recurrence; however, rivaroxaban and edoxaban were also associated with an increased risk of bleeding events. For primary prevention of CAT in ambulatory cancer patients starting chemotherapy, apixaban and rivaroxaban showed better efficacy than placebo but a trend towards higher bleeding rates. Recent guidelines suggest the DOACs for the treatment of CAT in selected cancer patients (eg, low bleeding risk, no luminal gastrointestinal or genitourinary malignancies, no interfering medications). The DOACs are also suggested for primary thromboprophylaxis in selected ambulatory cancer patients at high risk of VTE (eg, Khorana score ≥2 prior to starting new chemotherapy, low bleeding risk, no interfering medications).

Long-Term Management of Pulmonary Embolism: A Review of Consequences, Treatment, and Rehabilitation

The concept of pulmonary embolism is evolving. Recent and emerging evidence on the treatment of specific patient populations, its secondary prevention, long-term complications, and the unmet need for rehabilitation has the potential to change clinical practice for the benefit of the patients. This review discusses the recent evidence from clinical trials, observational studies, and guidelines focusing on anticoagulation treatment, rehabilitation, emotional stress, quality of life, and the associated outcomes for patients with pulmonary embolism. Guidelines suggest that the type and duration of treatment with anticoagulation should be based on prevalent risk factors. Recent studies demonstrate that an anticoagulant treatment that is longer than two years may be effective and safe for some patients. The evidence for extended treatment in cancer patients is limited. Careful consideration is particularly necessary for pulmonary embolisms in pregnancy, cancer, and at the end of life. The rehabilitation and prevention of unnecessary deconditioning, emotional distress, and a reduced quality of life is an important, but currently they are unmet priorities for many patients with a pulmonary embolism. Future research could demonstrate optimal anticoagulant therapy durations, follow-ups, and rehabilitation, and effective patient-centered decision making at the end of life. A patient preferences and shared decision making should be incorporated in their routine care when weighing the benefits and risks with primary treatment and secondary prevention.

Acute Pulmonary Embolism: A Review

IMPORTANCE

Pulmonary embolism (PE) is characterized by occlusion of blood flow in a pulmonary artery, typically due to a thrombus that travels from a vein in a lower limb. The incidence of PE is approximately 60 to 120 per 100 000 people per year. Approximately 60 000 to 100 000 patients die from PE each year in the US.

OBSERVATIONS

PE should be considered in patients presenting with acute chest pain, shortness of breath, or syncope. The diagnosis is determined by chest imaging. In patients with a systolic blood pressure of at least 90 mm Hg, the following 3 steps can be used to evaluate a patient with possible PE: assessment of the clinical probability of PE, D-dimer testing if indicated, and chest imaging if indicated. The clinical probability of PE can be assessed using a structured score or using clinical gestalt. In patients with a probability of PE that is less than 15%, the presence of 8 clinical characteristics (age <50 years, heart rate <100/min, an oxygen saturation level of > 94%, no recent surgery or trauma, no prior venous thromboembolism event, no hemoptysis, no unilateral leg swelling, and no estrogen use) identifies patients at very low risk of PE in whom no further testing is needed. In patients with low or intermediate clinical probability, a D-dimer level of less than 500 ng/mL is associated with a posttest probability of PE less than 1.85%. In these patients, PE can be excluded without chest imaging. A further refinement of D-dimer threshold is possible in patients aged 50 years and older, and in patients with a low likelihood of PE. Patients with a high probability of PE (ie, >40% probability) should undergo chest imaging, and D-dimer testing is not necessary. In patients with PE and a systolic blood pressure of 90 mm Hg or higher, compared with heparin combined with a vitamin K antagonist such as warfarin followed by warfarin alone, direct oral anticoagulants such as apixaban, edoxaban, rivaroxaban, or dabigatran, are noninferior for treating PE and have a 0.6% lower rate of bleeding. In patients with PE and systolic blood pressure lower than 90 mm Hg, systemic thrombolysis is recommended and is associated with an 1.6% absolute reduction of mortality (from 3.9% to 2.3%).

CONCLUSIONS AND RELEVANCE

In the US, PE affects approximately 370 000 patients per year and may cause approximately 60 000 to 100 000 deaths per year. First-line therapy consists of direct oral anticoagulants such as apixaban, edoxaban, rivaroxaban, or dabigatran, with thrombolysis reserved for patients with systolic blood pressure lower than 90 mm Hg.

Homozygous factor V leiden mutation: Rare etiology of pulmonary embolism

Introduction and importance

Venous thromboembolic disease (VTE), which includes pulmonary embolism (PE) and deep vein thrombosis (DVT), is a major public health problem with high morbidity and mortality. The main risk factors for VTE are surgery, active cancer, immobilization, trauma or fracture, pregnancy and estrogen therapy. Genetic risk factors are also present and are dominated by the factor V Leiden mutation, which is present in 20% of VTE and in 2–5% of the general population with an annual incidence of 0.1% (Margaglione and Grandone, 2011; Ridker et al., 1995) [4,5]. This mutation can be heterozygous or homozygous, which is rarer. In this context, we report the case of a 37-year-old patient with no medical or surgical history and no notable risk factors who was admitted to the emergency room for the management of acute dyspnea at rest in connection with a bilateral proximal pulmonary embolism originating from a homozygous factor V Leiden mutation.

Despite the efforts of the World Health organization, pulmonary embolism remains a major cause of morbidity and mortality in our days, and the etiological assessment is performed in a very few cases, which makes the management standardized and not specific. That is why it is important to make an etiological assessment in a systematic way especially in young subjects for an optimal management and to avoid recurrences.

Case presentation

Here, we report a rare case of a 37-year-old patient, who was admitted for the management of resting dyspnea related to bilateral proximal pulmonary embolism, in whom the etiological work-up was in favor of a homozygous factor V Leiden mutation. This case shows diagnostic difficulties and management of this rare disease.

•

Pulmonary embolism is a frequent and potentially serious pathology.

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The etiological assessment of pulmonary embolism is not carried out in a systematic way which makes the management not optimal with the possibility of repeated pulmonary embolism.

•

Long-term anticoagulation is the mainstay of treatment for pulmonary embolism secondary to factor V Leiden mutation.

Anticoagulant for treatment and prophylaxis of venous thromboembolism patients with renal dysfunction: A systematic review and network meta-analysis

Objective

The aim of this study was to compare the efficacy and safety for particular regimen and dosage in venous thromboembolism (VTE) patients with renal insufficiency.

Methods

English language searches of PubMed, Embase, and Web of Science (inception to May 2021). RCTs evaluating anticoagulants for VTE treatment at acute phase, extension phase, and VTE prophylaxis in patients with renal insufficiency and reporting efficacy (death, recurrence, or occurrence of VTE) and safety (bleeding) outcomes were selected. The methodological quality of each study included was assessed at the outcome level using the risk-of-bias assessment tool developed by the Cochrane Bias Methods Group.

Results

Twenty-one trials that involved 76,574 participants and 8,972 (11.7%) patients with renal insufficiency were enrolled, including 10 trials on VTE treatment in acute phase (3–12 months), four trials on VTE treatment in extension phase (6–36 months), and seven trials for VTE prophylaxis. For acute VTE treatment, compared with dabigatran etexilate, apixaban (RR 5.90, 95%CI 1.00–34.60) and rivaroxaban (RR 6.18, 95%CI 1.17–32.75) were significantly associated with increased risk of death or recurrence. For extension treatment of VTE, aspirin had the highest probability of the most effective and safest treatment, followed by apixaban. For VTE prophylaxis, compared with enoxaparin, desirudin was associated with lower risk of VTE occurrence (RR 0.56, 95% CI 0.34–0.91), but had higher risk of bleeding than dabigatran etexilate.

Conclusion

The network meta-analysis informs the optimal choice of anticoagulants and their particular dosage for treatment and prophylaxis of VTE patients comorbid renal insufficiency.

Systematic review registration

www.crd.york.ac.uk/prospero/, identifier: CRD42021254086.

Warfarin is associated with higher rates of epistaxis compared to direct oral anticoagulants: A nationwide propensity score-weighted study

BACKGROUND

Although epistaxis is one of the most common side effects of oral anticoagulation, it is unclear whether epistaxis rates vary between different oral anticoagulants (OAC).

OBJECTIVE

To compare rates of clinically relevant epistaxis between OAC.

METHODS

Epistaxis event rates were compared between new users of apixaban, dabigatran, rivaroxaban, and warfarin in a nationwide population-based cohort study over a 5-year study period, 2014-2019. Data was collected from the Icelandic Medicine Registry and the five major hospitals in Iceland. Inverse probability weighting (IPW) was used to yield balanced baseline characteristics, and epistaxis rates were compared using Kaplan-Meier survival estimates and Cox regression.

RESULTS

During the study period, 2098 patients received apixaban, 474 dabigatran, 3106 rivaroxaban, and 1403 warfarin. In total, 93 patients presented with clinically relevant epistaxis, including 11 (12%) major epistaxis events and one fatal epistaxis episode. Furthermore, seven patients (9%) with non-major epistaxis later presented with major bleeding during the follow-up period. Warfarin use was associated with higher rates of epistaxis compared to apixaban (2.2 events per 100-person years (events/100-py) vs. 0.6 events/100-py, hazard ratio [HR] 4.22, 95% confidence interval [CI] 2.08-8.59, p < 0.001), rivaroxaban (2.2 events/100-py vs. 1.0 events/100-py, HR 2.26, 95% CI 1.28-4.01, p = 0.005), and dabigatran (2.2 events/100-py vs. no events, HR n/a, p < 0.001).

CONCLUSION

Warfarin treatment was associated with higher rates of clinically relevant epistaxis compared to direct oral anticoagulants.

How Would You Treat This Patient With Pulmonary Embolism? : Grand Rounds Discussion From Beth Israel Deaconess Medical Center

Pulmonary embolism can be acutely life-threatening and is associated with long-term consequences such as recurrent venous thromboembolism and chronic thromboembolic pulmonary hypertension. In 2020, the American Society of Hematology published updated guidelines on the management of patients with venous thromboembolism. Here, a hematologist and a cardiology and vascular medicine specialist discuss these guidelines in the context of the care of a patient with pulmonary embolism. They discuss advanced therapies such as catheter-directed thrombolysis in the short-term management of patients with intermediate-risk disease, recurrence risk stratification at presentation, and ideal antithrombotic regimens for patients whose pulmonary embolism was associated with a transient minor risk factor.

Anticoagulant Effects of Dabigatran on Coagulation Laboratory Parameters in Pediatric Patients: Combined Data from Five Pediatric Clinical Trials

Background  Dabigatran etexilate, a direct oral thrombin inhibitor, is approved to treat venous thromboembolism (VTE) in both adults and children.

Objectives  This population analysis characterized relationships between dabigatran total plasma concentrations and coagulation laboratory parameters (activated partial thromboplastin time [aPTT]; diluted thrombin time [dTT]; ecarin clotting time [ECT]).

Methods  Data from three phase 2a and one single-arm and one randomized, comparative phase 2b/3 pediatric studies (measurements: aPTT 2,925 [ N  = 358]; dTT 2,348 [ N  = 324]; ECT 2,929 [ N  = 357]) were compared with adult data (5,740 aPTT, 3,472 dTT, 3,817 ECT measurements; N  = 1,978). Population models were fitted using nonlinear mixed-effects modeling. Covariates (e.g., sex, age) were assessed on baseline and drug-effect parameters, using a stepwise covariate model-building procedure.

Results  Overall, relationships between dabigatran, aPTT, dTT, and ECT were similar in children and adults. For children aged <6 months, a higher proportion of baseline samples were outside or close to the upper aPTT and ECT adult ranges. No age-related differences were detected for dTT. With increasing dabigatran concentration, aPTT rose nonlinearly (half the maximum effect at 368 ng/mL dabigatran) while dTT and ECT increased linearly (0.37 and 0.73% change per ng/mL dabigatran, respectively). Mean baseline aPTT (45 vs. 36 seconds) and ECT (40 vs. 36 seconds) were slightly increased for those aged <6 months versus older children.

Conclusion  The similar relationships of laboratory parameters observed across pediatric age groups suggests that developmental changes in the hemostatic system may have little effect on response to dabigatran.

Hemoclot Thrombin Inhibitor Assay and Expected Peak-Trough Levels of Dabigatran: A Multicenter Study

Purpose

Dabigatran concentrations monitoring are gaining importance of special situations, but limited data are available for the expected peak and trough levels. The hemoclot thrombin inhibitor (HTI) is dabigatran-calibrated quantitative determination of dabigatran concentration. This study aims to validate HTI assay as the quantification choice of dabigatran, and providing the expected peak and trough levels.

Materials and Methods

This is a multi-center methodology validate study, including seven hospitals from Beijing, Shanghai, Henan, Hunan, Chongqing, and Fujian. We retrospectively analyzed plasma samples taken from 118 healthy subjects and 183 patients receiving dabigatran. Dabigatran concentrations were measured with HTI assay and high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Linear regression, Spearman correlation and Bland-Altman analysis were used in this study.

Results

The mean concentration ratio of HPLC-MS/MS and HTI assays was 1.03 and 0.98 at 2 and 12 h, and the acceptance ranges for both the ratio limit as well as the limit of agreement were met, suggesting good agreement between the HTI-derived plasma concentrations and HPLC-MS/MS. The reference detection range of single dose dabigatran 150 mg in healthy subjects was 33–159 ng/ml. About 500 blood samples were taken from 183 patients suggested that the expected peak and trough levels range of dabigatran 110 mg was about 95–196 and 36–92 ng/ml.

Conclusion

Hemoclot thrombin inhibitor assay can be a good quantitative detection method of dabigatran. Expected peak and trough levels provide a basis for the rational use of dabigatran, and provide important Asian population data for the update of the international clinical guidelines for hematological testing.

Clinical Trial Registration

[https://clinicaltrials.gov], identifier [NCT03161496].

Extended Anticoagulation After Pulmonary Embolism: A Multicenter Observational Cohort Analysis

Background Pulmonary embolism (PE) has a long-term risk of adverse events, which can be prevented by extended anticoagulation. We compared clinical characteristics and outcomes between patients treated with 2-year extended anticoagulation and those who were not, in a population who had completed an initial phase of 3 to 6 months of anticoagulant therapy after acute PE. Methods and Results Observational cohort analysis of patients with PE who survived an initial phase of 3 to 6 months anticoagulation. Primary efficacy outcome was all-cause death or recurrent venous thromboembolism. Primary safety outcome was major bleeding. In total, 858 (71.5%) patients were treated with and 341 (28.5%) were treated without extended anticoagulant therapy during the active study period. Age <65 years, intermediate-high or high-risk index PE, normal platelet count, and the absence of concomitant antiplatelet treatment were independently associated with the prescription of extended anticoagulation. The mean duration of the active phase was 2.1±0.3 years. The adjusted rate of the primary efficacy outcome was 2.1% in the extended group and 7.7% in the nonextended group (P<0.001) for patients treated with extended anticoagulant therapy. Rate of bleeding were similar between the extended anticoagulant group and the nonextended group. Conclusions Extended oral anticoagulation over 2 and a half years after index PE seems to provide a net clinical benefit compared with no anticoagulation in patients with PE selected to receive extended anticoagulation. Randomized clinical trials are warranted to explore the potential benefit of extended anticoagulation in patients with PE, especially those with transient provoking factors but residual risk.

Efficacy and Safety Considerations With Dose-Reduced Direct Oral Anticoagulants: A Review

Importance

Dose-reduced regimens of direct oral anticoagulants (DOACs) may be used for 2 main purposes: dose-adjusted treatment intended as full-intensity anticoagulation (eg, for stroke prevention in atrial fibrillation [AF] in patients requiring dose reduction) or low-intensity treatment (eg, extended-duration treatment of venous thromboembolism [VTE]). We reviewed randomized clinical trials (RCTs) to understand the scenarios in which dose-adjusted or low-intensity DOACs were tested and reviewed the labeled indications by regulatory authorities, using data from large registries to assess whether the use of dose-reduced DOACs in routine practice aligned with the findings of RCTs.

Observations

Among 4191 screened publications, 35 RCTs that used dose-adjusted DOACs were identified for dabigatran, apixaban, rivaroxaban, and edoxaban. Of these 35 RCTs, 29 were related to stroke prevention in AF. Efficacy and safety results for dose-adjusted DOACs in large RCTs of AF were similar to those found for full-dose DOACs. To our knowledge, dabigatran, apixaban, and rivaroxaban have not been studied as dose-adjusted therapy for acute VTE treatment. Low-intensity DOACs were identified in 37 RCTs. Low-intensity DOACs may be used for extended-duration treatment of VTE (apixaban and rivaroxaban), primary prevention in orthopedic surgeries (dabigatran, apixaban, and rivaroxaban), primary prevention in ambulatory high-risk cancer patients (apixaban and rivaroxaban) or (postdischarge) high-risk medical patients (rivaroxaban), in stable atherosclerotic vascular disease, or after a recent revascularization for peripheral artery disease in conjunction with aspirin (rivaroxaban). Minor variations exist between regulatory authorities in different regions regarding criteria for dose adjustment of DOACs. Data from large registries indicated that dose-reduced DOACs were used occasionally with doses or for clinical scenarios different from those studied in RCTs or recommended by regulatory authorities.

Conclusions and Relevance

Dose adjustment and low-intensity treatment are 2 different forms of dose-reduced DOACs. Dose adjustment is mostly relevant for AF and should be done based on the approved criteria. Dose adjustment of DOACs should not be used for acute VTE treatment in most cases. In contrast, low-intensity DOACs may be used for primary or secondary VTE prevention for studied and approved indications. Attention should be given to routine practice patterns to align the daily clinical practice with existing evidence of safety and efficacy.

Comparative Risks of Fracture Among Direct Oral Anticoagulants and Warfarin: A Systematic Review and Network Meta-Analysis

Importance

Previous studies have shown the effectiveness and safety of direct oral anticoagulants (DOACs), including lower fracture risks, compared to warfarin. However, direct or indirect comparisons between different DOACs are scarce in the literature.

Objective

This study aims to compare fracture risks among different DOACs and warfarin, including apixaban, rivaroxaban, dabigatran, and edoxaban, in patients with non-valvular atrial fibrillation (NVAF) or venous thromboembolism (VTE).

Methods

We searched PubMed/MEDLINE, Embase, Cochrane CENTRAL, and Web of Science for randomized controlled trials and cohort studies comparing the fracture risks among patients who used warfarin or DOACs, up to March 2021. Two authors extracted data and appraised the risk of bias of included studies. The primary outcome was fracture risk. We performed pairwise meta-analyses to compare differences between medications and network meta-analyses using frequentist random-effects models to compare through indirect evidence. We used surface under the cumulative ranking curve (SUCRA) and mean ranks to determine the probability of a DOAC ranking best in terms of fracture risk.

Results

Thirty-one studies were included in the final analysis. Twenty-four randomized controlled trials and seven cohort studies with 455,343 patients were included in the systematic review and network meta-analysis. Compared to warfarin, the risk of any fractures was lowest with apixaban [relative risk (RR) = 0.59; 95% confidence interval (CI): 0.48-0.73], followed by rivaroxaban (RR: 0.72; 95% CI: 0.60-0.86), edoxaban (RR: 0.88; 95% CI: 0.62-1.23), and dabigatran (RR = 0.90; 95% CI: 0.75-1.07). No substantial inconsistency between direct and indirect evidence was detected for all outcomes.

Conclusions

All DOACs were safer than warfarin concerning the risk of fracture; however, apixaban had the lowest relative risk of fracture within the class of DOACs. Further head-to-head prospective studies should confirm the comparative safety profiles of DOACs regarding fractures.

Anticoagulants: dose control methods and inhibitors

These days, anticoagulants are in great demand. They are used as a prophylaxis for thromboembolic complications in various diseases and conditions in general therapeutic practice, cardiology, neurology, as well as obstetrics to manage high-risk pregnancies. The relevance of anticoagulants competent use has come to the fore in connection with the emergence of a new disease – COVID-19 and its serious complications such as developing thrombotic storm, in which the timely applied anticoagulant therapy is the key to the success of therapy. The risk of bleeding should be considered when using any anticoagulant. Age, impaired renal function and concomitant use of antiplatelet agents are common risk factors for bleeding. Moreover, only vitamin K antagonists and heparin have specific antidotes – vitamin K and protamine, respectively. Inhibitors of other anticoagulants are universal presented as inactivated or activated prothrombin complex concentrate and recombinant factor VIIa. Hemodialysis effectively reduces dabigatran concentration, activated charcoal is effective in the case of recent oral administration of lipophilic drugs. Research on new antidotes of currently available anticoagulants is under way, similar to testing of new types of anticoagulants that are sufficiently effective in preventing and treating thromboembolic complications with minimal risk of hemorrhagic. The main contraindication to anticoagulants use is the doctor's ignorance of the mechanisms of drug action and opportunities for suppressing its effect.

Extended Anticoagulation for Venous Thromboembolism: A Survey of the American Venous Forum and the European Venous Forum

OBJECTIVE

Extended anticoagulation should always be considered after standard treatment for an unprovoked episode of venous thromboembolism (VTE). It may also be considered in selected patients with provoked VTE. However, evidence-based protocols suggested by some clinical guidelines and risk assessment tools to guide this practice are limited and ambiguous. The goal of this survey research was to analyze current practices in applying extended anticoagulation therapy in patients with VTE among members of the American Venous Forum (AVF) and the European Venous Forum (EVF).

METHODS

An online survey was created by the AVF Research Committee. The survey consisted of sixteen questions to identify the country of practice, specialty, experience of participating physicians, and their clinical practice patterns in applying extended anticoagulation in VTE patients. The survey was distributed over email to the members of the AVF and EVF.

RESULTS

A total of 144 practitioners, 48 (33%) AVF members and 96 (66%) EVF members, participated in the survey. The majority of respondents identified themselves as vascular specialists with primary certification in vascular surgery (70%), vascular medicine/angiology (9%), and venous disease/phlebology (3%). Seventy-two percent of participants believe that the risk of VTE recurrence generally overweighs the risk of bleeding in patients with unprovoked VTE. Extended anticoagulation may be utilized by 97% of providers. Different patterns in real world clinical practice were identified. More than half of practitioners estimated VTE recurrence and bleeding risk subjectively. The antithrombotic drugs most commonly used for secondary prophylaxis were rivaroxaban, apixaban, warfarin, dabigatran, and aspirin, in decreasing order of frequency. Among the reasons selected for not considering extended anticoagulation on a regular basis were the lack of specific clinical practice guidelines (24%), the lack of published evidence (9%), and the absence of valid VTE/bleeding risk prediction calculators (8%). Twelve participants (8%) stated that extended anticoagulation was not beneficial for the majority of patients with VTE. Ten participants (7%) indicated that prescribing extended anticoagulation was outside the scope of their specialty.

CONCLUSIONS

There are different practice patterns in extending anticoagulation beyond the standard treatment in patients with VTE. Major gaps in knowledge remain a serious challenge at least partially explaining inaccuracy and inconsistency in long-term VTE management. Appropriately designed studies are needed to evaluate risk stratification tools when contemporary best medical therapy is used, accurately predict VTE recurrence and its long-term outcomes, and to tailor safe and effective secondary prophylaxis.

Physician perceptions and use of reduced-dose direct oral anticoagulants for extended phase venous thromboembolism treatment

Background

The direct oral anticoagulants (DOACs), apixaban and rivaroxaban, have been studied for extended-phase treatment of venous thromboembolism (VTE). Yet, scant evidence exists surrounding clinician practice and decision-making regarding dose reduction.

Aims

Report clinician practice and characteristics surrounding dose reduction of DOACs for extended-phase VTE treatment.

Methods

We conducted a 16-question REDCap survey between July 14, 2021, and September 13, 2021, among ISTH 2021 Congress attendees and on Twitter. We explored factors associated with dose reduction using logistic regression. We used k-means clustering to identify distinct groups of dose-reduction decision-making. Random forest analysis explored demographics with respect to identified groups.

Results

Among 171 respondents, most were attending academic physicians from North America. Clinicians who treated larger volumes of patients had higher odds of dose reduction. We identified five clusters that showed distinct patterns of behavior regarding dose reduction. Cluster 1 rarely dose reduces and likely prescribes rivaroxaban over apixaban; cluster 2 dose reduces frequently, does not consider age when dose-reducing, is least likely to temporarily reescalate dosing, and prescribes apixaban and rivaroxaban equally; cluster 3 dose reduces <50% of the time, and temporarily reescalates dosing during increased VTE risk; cluster 4 dose reduces frequently, temporarily reescalates dosing, and is most likely to prescribe apixaban over rivaroxaban; and cluster 5 dose reduces most frequently, and takes the fewest risk factors into consideration when deciding to dose reduce.

Conclusions

Most clinicians elect to dose-reduce DOACs for extended-phase anticoagulation. The likelihood of a clinician to dose reduce increases with volume of patients treated. Clinician prescribing patterns cluster around VTE risk factors as well as reescalation during high-risk periods.

Invasive and Pharmacological Treatment of Deep Vein Thrombosis: a Scoping Review

The annual occurrence of venous thromboembolism (VTE) is 300,000-600,000 cases in the United States and 700,000 in Europe. VTE includes deep venous thrombosis (DVT) of upper or lower extremities, superior and inferior vena cava thrombosis, and pulmonary embolism (PE) as well. The primary treatment of DVT includes oral anticoagulation to prevent the progression of the thrombus and decrease the risk of pulmonary embolism. Depending on the symptoms, more invasive treatments can be applied to target the iliofemoral thrombus and its removal. However, less emphasis is given to acute symptomatology, early recovery of function, quality of life improvement, and the individualized likelihood of developing post-thrombotic syndrome. While invasive therapy has been used to enhance the acute management of iliofemoral DVT, our knowledge about the overall outcomes associated with the invasive treatment of VTE is still limited. In this review, we illustrate the available data on pharmacological and endovascular management of iliofemoral VTE, including therapies such as catheter-directed thrombolysis (CDT), mechanical thrombectomy (PMT), and pharmacomechanical catheter-directed thrombolysis (PCDT).

Contemporary clinical management of acute pulmonary embolism: the COPE study

BACKGROUND

New management, risk stratification and treatment strategies have become available over the last years for patients with acute pulmonary embolism (PE), potentially leading to changes in clinical practice and improvement of patients' outcome.

METHODS

The COntemporary management of Pulmonary Embolism (COPE) is a prospective, non-interventional, multicentre study in patients with acute PE evaluated at internal medicine, cardiology and emergency departments in Italy. The aim of the COPE study is to assess contemporary management strategies in patients with acute, symptomatic, objectively confirmed PE concerning diagnosis, risk stratification, hospitalization and treatment and to assess rates and predictors of in-hospital and 30-day mortality. The composite of death (either overall or PE-related) or clinical deterioration at 30 days from the diagnosis of PE, major bleeding occurring in hospital and up to 30 days from the diagnosis of PE and adherence to guidelines of the European Society of Cardiology (ESC) are secondary study outcomes. Participation in controlled trials on the management of acute PE is the only exclusion criteria. Expecting a 10-15%, 3% and 0.5% incidence of death for patients with high, intermediate or low-risk PE, respectively, it is estimated that 400 patients with high, 2100 patients with intermediate and 2500 with low-risk PE should be included in the study. This will allow to have about 100 deaths in study patients and will empower assessment of independent predictors of death.

CONCLUSIONS

COPE will provide contemporary data on in-hospital and 30-day mortality of patients with documented PE as well as information on guidelines adherence and its impact on clinical outcomes.

TRAIL REGISTRATION

NCT number: NCT03631810.

Association of Type of Oral Anticoagulant Dispensed With Adverse Clinical Outcomes in Patients Extending Anticoagulation Therapy Beyond 90 Days After Hospitalization for Venous Thromboembolism

IMPORTANCE

Guidelines for managing venous thromboembolism (VTE) recommend at least 90 days of therapy with oral anticoagulants. Limited evidence exists about the optimal drug for continuing therapy beyond 90 days.

OBJECTIVE

To compare having prescriptions dispensed for apixaban, rivaroxaban, or warfarin after an initial 90 days of anticoagulation therapy for the outcomes of hospitalization for recurrent VTE, major bleeding, and death.

DESIGN, SETTING, AND PARTICIPANTS

This exploratory retrospective cohort study used data from fee-for-service Medicare (2009-2017) and from 2 commercial health insurance (2004-2018) databases and included 64 642 adults who initiated oral anticoagulation following hospitalization discharge for VTE and continued treatment beyond 90 days.

EXPOSURES

Apixaban, rivaroxaban, or warfarin prescribed after an initial 90-day treatment for VTE.

MAIN OUTCOMES AND MEASURES

Primary outcomes included hospitalization for recurrent VTE and hospitalization for major bleeding. Analyses were adjusted using propensity score weighting. Patients were followed up from the end of the initial 90-day treatment episode until treatment cessation, outcome, death, disenrollment, or end of available data. Weighted Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% CIs.

RESULTS

The study included 9167 patients prescribed apixaban (mean [SD] age, 71 [14] years; 5491 [59.9%] women), 12 468 patients prescribed rivaroxaban (mean [SD] age, 69 [14] years; 7067 [56.7%] women), and 43 007 patients prescribed warfarin (mean [SD] age, 70 [15] years; 25 404 [59.1%] women). The median (IQR) follow-up was 109 (59-228) days for recurrent VTE and 108 (58-226) days for major bleeding outcome. After propensity score weighting, the incidence rate of hospitalization for recurrent VTE was significantly lower for apixaban compared with warfarin (9.8 vs 13.5 per 1000 person-years; HR, 0.69 [95% CI, 0.49-0.99]), but the incidence rates were not significantly different between apixaban and rivaroxaban (9.8 vs 11.6 per 1000 person-years; HR, 0.80 [95% CI, 0.53-1.19]) or rivaroxaban and warfarin (HR, 0.87 [95% CI, 0.65-1.16]). Rates of hospitalization for major bleeding were 44.4 per 1000 person-years for apixaban, 50.0 per 1000 person-years for rivaroxaban, and 47.1 per 1000 person-years for warfarin, yielding HRs of 0.92 (95% CI, 0.78-1.09) for apixaban vs warfarin, 0.86 (95% CI, 0.71-1.04) for apixaban vs rivaroxaban, and 1.07 (95% CI, 0.93-1.24) for rivaroxaban vs warfarin.

CONCLUSIONS AND RELEVANCE

In this exploratory analysis of patients prescribed extended-duration oral anticoagulation therapy after hospitalization for VTE, prescription dispenses for apixaban beyond 90 days, compared with warfarin beyond 90 days, were significantly associated with a modestly lower rate of hospitalization for recurrent VTE, but no significant difference in rate of hospitalization for major bleeding. There were no significant differences for comparisons of apixaban vs rivaroxaban or rivaroxaban vs warfarin.

Comparative efficacy and safety of oral anticoagulants for the treatment of venous thromboembolism in the patients with different renal functions: a systematic review, pairwise and network meta-analysis

OBJECTIVES

To compare the efficacy and safety of direct oral anticoagulants (DOACs) in patients with venous thromboembolism (VTE) and different renal functions.

DESIGN

Systematic review containing pairwise and Bayesian network meta-analysis of randomised controlled trials (RCTs).

DATA SOURCES

MEDLINE, EMBASE and Cochrane Library.

ELIGIBILITY CRITERIA

RCTs reporting the efficacy and safety outcomes of DOACs in different creatinine clearance (CrCl) subgroups.

DATA EXTRACTION AND SYNTHESIS

Data extraction and quality assessment were undertaken by two independent reviewers. Data were pooled using the DerSimonian-Laird method in pairwise meta-analysis. Network meta-analysis within a Bayesian framework was conducted.

RESULTS

Data from 10 RCTs were included. In the treatment of acute VTE, DOACs did not significantly reduce recurrent VTE or VTE-related death (OR, 0.96; 95% CI, 0.82 to 1.11) but significantly reduced bleeding events (0.76, 0.68 to 0.90) compared with warfarin. In the extended treatment of VTE, DOACs produced significant benefits in recurrent VTE or VTE-related death (0.23, 0.16 to 0.29), but significantly increased bleeding events (1.86, 1.04 to 3.33) compared with placebo/aspirin. There were no significant differences in efficacy and safety of DOACs among the three CrCl stratified subgroups in acute and extended treatment of VTE (p for subgroup heterogeneity >0.1). Bayesian network meta-analysis suggested that apixaban 2.5 mg and 5 mg two times per day were associated with a lower risk of bleeding than dabigatran, rivaroxaban, warfarin and aspirin in the subgroup with CrCl >80 mL/min.

CONCLUSIONS

For the treatment of acute VTE, DOACs are similar to warfarin in reducing recurrent VTE and VTE-related death but are significantly superior to warfarin in reducing the risk of bleeding. For the efficacy and safety of DOACs across different CrCl stratifications (30-50, 50-80 and more than 80 mL/min), no significant difference was found. In light of minimal evidence, apixaban might be associated with a lower risk of bleeding in patients with VTE and CrCl >80 mL/min.

PROSPERO REGISTRATION NUMBER

CRD42018090896.

Adverse Events of DOACs in Children

Venous thromboembolism (VTE) has an increasing rate of significance in pediatric patients. The currently standardized anticoagulants (unfractionated heparin, low molecular weight heparin and vitamin K antagonists) and their dose regimens were not comprehensively trialed in pediatric patients. Recently, several direct oral anticoagulants (DOACs) have been studied in clinical trials in the pediatric population and further trials are ongoing. Dabigatran etexilate and rivaroxaban results show that these DOACs are safe and efficient in the treatment and secondary prevention of pediatric VTE. This review will focus on adverse events (AEs) between specific DOACs reported in the clinical trials in children and compare them to standard of care. This will assist clinicians in decision making of selecting the right anticoagulation for their pediatric patients.

Severe Bleeding Risks of Direct Oral Anticoagulants in the Prevention and Treatment of Venous Thromboembolism: A Network Meta-Analysis of Randomised Controlled Trials

OBJECTIVE

The aim of this study was to determine the severe bleeding safety of direct oral anticoagulants (DOACs) for the prevention and treatment of venous thromboembolism (VTE).

METHODS

PubMed, EMBASE, Web of Science, and the Cochrane Library databases were searched up to 6 January 2021. The incidence of severe bleeding (major, gastrointestinal [GI], intracranial, and fatal) was investigated. Using frequentist network meta-analysis, interventions that were not compared directly could be compared indirectly by the 95% confidence interval (CI), making the search results more intuitive. Based on surface under the cumulative ranking curves (SUCRA), the relative ranking probability of each group was generated.

RESULTS

Thirty-one randomised controlled trials (76 641 patients) were included. For the treatment of VTE, the risk of major bleeding with apixaban was significantly lower than dabigatran (odds ratio [OR] 2.10, 95% CI 1.07 - 4.12) and edoxaban (OR 2.64, 95% CI 1.36 - 5.15). The safety of the drugs was ranked from highest to lowest as follows: major bleeding: apixaban (SUCRA 98.0), rivaroxaban (SUCRA 69.6), dabigatran (SUCRA 50.7), edoxaban (SUCRA 26.5), and vitamin K antagonists (VKAs; SUCRA 5.1); GI bleeding: apixaban (SUCRA 80.7), rivaroxaban (SUCRA 66.8), edoxaban (SUCRA 62.3), VKAs (SUCRA 34.4), and dabigatran (SUCRA 5.8); intracranial bleeding: rivaroxaban (SUCRA 74.4), edoxaban (SUCRA 70.4), dabigatran (SUCRA 58.2), apixaban (SUCRA 44.4), and VKAs (SUCRA 5.6); fatal bleeding: edoxaban (SUCRA 82.7), rivaroxaban (SUCRA 59.2), dabigatran (SUCRA 48.6), apixaban (SUCRA 43.0), and VKAs (SUCRA 16.3). For the prevention of VTE, the risk of major bleeding with apixaban was significantly lower than rivaroxaban (OR 2.14, 95% CI 1.02 - 4.52). Among the four types of bleeding, apixaban had the lowest bleeding risk among DOACs (major bleeding: SUCRA 81.6; GI bleeding: SUCRA 75.4; intracranial bleeding: SUCRA 64.1; fatal bleeding: SUCRA 73.6).

CONCLUSIONS

For the treatment of VTE, in terms of major bleeding and GI bleeding, apixaban had the lowest bleeding risk; in terms of intracranial bleeding, rivaroxaban had the lowest bleeding risk; in terms of fatal bleeding, edoxaban had the lowest bleeding risk. For the prevention of VTE, apixaban had the lowest bleeding risk.

Anticoagulation for the initial treatment of venous thromboembolism in people with cancer

BACKGROUND

Compared with people without cancer, people with cancer who receive anticoagulant treatment for venous thromboembolism (VTE) are more likely to develop recurrent VTE.

OBJECTIVES

To compare the efficacy and safety of three types of parenteral anticoagulants (i.e. fixed-dose low molecular weight heparin (LMWH), adjusted-dose unfractionated heparin (UFH), and fondaparinux) for the initial treatment of VTE in people with cancer.

SEARCH METHODS

We performed a comprehensive search in the following major databases: Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (via Ovid) and Embase (via Ovid). We also handsearched conference proceedings, checked references of included studies, and searched for ongoing studies. This update of the systematic review is based on the findings of a literature search conducted on 14 August 2021.

SELECTION CRITERIA

Randomised controlled trials (RCTs) assessing the benefits and harms of LMWH, UFH, and fondaparinux in people with cancer and objectively confirmed VTE.

DATA COLLECTION AND ANALYSIS

Using a standardised form, we extracted data - in duplicate - on study design, participants, interventions, outcomes of interest, and risk of bias. Outcomes of interest included all-cause mortality, symptomatic VTE, major bleeding, minor bleeding, postphlebitic syndrome, quality of life, and thrombocytopenia. We assessed the certainty of evidence for each outcome using the GRADE approach.

MAIN RESULTS

Of 11,484 identified citations, 3073 were unique citations and 15 RCTs fulfilled the eligibility criteria, none of which were identified in the latest search. These trials enrolled 1615 participants with cancer and VTE: 13 compared LMWH with UFH; one compared fondaparinux with UFH and LMWH; and one compared dalteparin with tinzaparin, two different types of low molecular weight heparin. The meta-analyses showed that LMWH may reduce mortality at three months compared to UFH (risk ratio (RR) 0.66, 95% confidence interval (CI) 0.40 to 1.10; risk difference (RD) 57 fewer per 1000, 95% CI 101 fewer to 17 more; low certainty evidence) and may reduce VTE recurrence slightly (RR 0.69, 95% CI 0.27 to 1.76; RD 30 fewer per 1000, 95% CI 70 fewer to 73 more; low certainty evidence). There were no data available for bleeding outcomes, postphlebitic syndrome, quality of life, or thrombocytopenia. The study comparing fondaparinux with heparin (UFH or LMWH) found that fondaparinux may increase mortality at three months (RR 1.25, 95% CI 0.86 to 1.81; RD 43 more per 1000, 95% CI 24 fewer to 139 more; low certainty evidence), may result in little to no difference in recurrent VTE (RR 0.93, 95% CI 0.56 to 1.54; RD 8 fewer per 1000, 95% CI 52 fewer to 63 more; low certainty evidence), may result in little to no difference in major bleeding (RR 0.82, 95% CI 0.40 to 1.66; RD 12 fewer per 1000, 95% CI 40 fewer to 44 more; low certainty evidence), and probably increases minor bleeding (RR 1.53, 95% CI 0.88 to 2.66; RD 42 more per 1000, 95% CI 10 fewer to 132 more; moderate certainty evidence). There were no data available for postphlebitic syndrome, quality of life, or thrombocytopenia. The study comparing dalteparin with tinzaparin found that dalteparin may reduce mortality slightly (RR 0.86, 95% CI 0.43 to 1.73; RD 33 fewer per 1000, 95% CI 135 fewer to 173 more; low certainty evidence), may reduce recurrent VTE (RR 0.44, 95% CI 0.09 to 2.16; RD 47 fewer per 1000, 95% CI 77 fewer to 98 more; low certainty evidence), may increase major bleeding slightly (RR 2.19, 95% CI 0.20 to 23.42; RD 20 more per 1000, 95% CI 14 fewer to 380 more; low certainty evidence), and may reduce minor bleeding slightly (RR 0.82, 95% CI 0.30 to 2.21; RD 24 fewer per 1000, 95% CI 95 fewer to 164 more; low certainty evidence). There were no data available for postphlebitic syndrome, quality of life, or thrombocytopenia.

AUTHORS' CONCLUSIONS

Low molecular weight heparin (LMWH) is probably superior to UFH in the initial treatment of VTE in people with cancer. Additional trials focusing on patient-important outcomes will further inform the questions addressed in this review. The decision for a person with cancer to start LMWH therapy should balance the benefits and harms and consider the person's values and preferences.

Differential Presentations of Arterial Thromboembolic Events Between Venous Thromboembolism and Atrial Fibrillation Patients

Objective: Atrial fibrillation (AF) and venous thromboembolism (VTE) share several risk factors related to arterial thromboembolism. No study has reported the differential contribution to arterial thromboembolic events and mortality between these two conditions in the same population. We therefore assessed the differential arterial thromboembolic events between AF and VTE. Methods: We included AF and VTE national cohorts derived from Taiwan National Health Insurance Research Database between 2001 and 2013. The eligible population was 314,861 patients in the AF cohort and 41,102 patients in the VTE cohort. The primary outcome was arterial thromboembolic events, including ischemic stroke, extracranial arterial thromboembolism (ECATE) and myocardial infarction (MI). Secondary outcomes were all-cause mortality and cardiovascular death. Results: After a 1:1 propensity matching, 32,688 patients in either group were analyzed. The risk of arterial thromboembolic events was lower in the VTE cohort than that in the AF cohort (subdistribution hazard ratio [SHR], 0.60; 95% confidence interval [CI], 0.57-0.62). The risk of ischemic stroke (SHR, 0.44; 95% CI, 0.42-0.46) and MI (SHR, 0.80; 95% CI, 0.72-0.89) were lower in the VTE cohort, while the risk of ECATE (SHR, 1.23; 95% CI, 1.14-1.33; particularly lower extremities) was higher in the VTE cohort. All-cause mortality rate was higher in the VTE cohort (HR, 1.18; 95% CI, 1.15-1.21) while the risk of cardiovascular death was lower in the VTE cohort (HR, 0.96; 95% CI, 0.93-0.995). Conclusions: Patients with AF had higher risks of arterial thromboembolic events compared to patients with VTE, despite having risk factors in common. The VTE cohort had higher risks of all-cause mortality and ECATE, particularly lower extremity events, compared to AF patients. The differential manifestations of thromboembolism sequelae and mortality between AF and VTE patients merit further investigation.

Major gastrointestinal bleeding risk with direct oral anticoagulants: Does type and dose matter? - A systematic review and network meta-analysis

The relative risk of major gastrointestinal bleeding (GIB) among different direct oral anticoagulants (DOACs) is debatable. Randomized controlled trials (RCTs) comparing DOACs with each other are lacking. We performed network meta-analysis to assess whether the risk of major GIB differs based on type and dose of DOAC. Literature search of PubMed, EMBASE and Cochrane databases from inception to August 2019, limited to English publications, was conducted to identify RCTs comparing DOACs with warfarin or enoxaparin for any indication. Primary outcome of interest was major GIB risk. We used frequentist network meta-analysis through the random-effects model to compare DOACs with each other and DOACs by dose to isolate the impact on major GIB. Twenty-eight RCTs, including 139 587 patients receiving six anticoagulants, were selected. The risk of major GIB for DOACs was equal to warfarin. Comparison of DOACs with each other did not show risk differences. After accounting for dose, rivaroxaban 20 mg, dabigatran 300 mg and edoxaban 60 mg daily had 47, 40 and 22% higher rates of major GIB versus warfarin, respectively. Apixaban 5 mg twice daily had lower major GIB compared to dabigatran 300 mg (OR, 0.63; 95% CI, 0.44-0.88) and rivaroxaban 20 mg (OR, 0.60; 95% CI, 0.43-0.83) daily. Heterogeneity was low, and the model was consistent without publication bias (Egger's test: P = 0.079). All RCTs were high-quality with low risk of bias. DOACs at standard dose, except apixaban, had a higher risk of major GIB compared to warfarin. Apixaban had a lower rate of major GIB compared to dabigatran and rivaroxaban.

Direct oral anticoagulants: A review for the non-specialist

Thrombin inhibitors and direct factor Xa inhibitors represent a major breakthrough in the field of anticoagulation pharmacotherapy. These novel agents have replaced warfarin as the oral anticoagulant of choice in certain indications, as they possess equal or superior efficacy and better safety profiles. They have a quick onset of action, predictable pharmacokinetic properties and minimal drug and food interactions. So they do not require frequent blood monitoring and dose adjustments as with warfarin. Considering all the advantages, there seems to be a rapid increase in the number of patients who are started on these novel anticoagulants. In this review, we highlight the pharmacology of these direct oral anticoagulants and the evidence-based indications for their use. We aim to provide a clinical overview for the non-specialist who may be called upon to manage a patient who is currently on one of these novel anticoagulants.

Long-term adherence to direct acting oral anticoagulants and the influence of health beliefs after switching from vitamin-K antagonists: Findings from the Switching Study

AIMS

Switching non-adherent patients prescribed anticoagulant treatment to a regime with less monitoring could lead to significant non-adherence. Health beliefs are known to influence medication adherence; however, the extent of this influence is unknown in patients switched from vitamin-K antagonists (VKAs) to direct oral anticoagulants (DOACs). This study aimed to determine adherence to long-term therapy in patients switched from VKAs to DOAC due to low time in therapeutic range (TTR) and if adherence is associated with health beliefs.

METHODS

The Switching Study is a longitudinal observational cohort study following patients for at least 1-year. 254 patients anticoagulated with VKAs for stroke prevention in atrial fibrillation (AF) or secondary prevention of venous thromboembolism (VTE) and TTR < 50% were recruited from anticoagulation clinics at King's College Hospital, London, UK. All participants were switched to DOAC and had health beliefs measured at baseline with VKA, 1-month and 12-months after switching.

RESULTS

Of the 220 patients who completed 12-month follow-up 39% had sub-optimal adherence measured by self-report. 23% were non-adherent according to prescriptions issued. Increasing concerns about anticoagulation over time relative to beliefs about necessity was associated with lower self-reported adherence (OR = 0.902 95%C.I: 0.836, 0.974; p = 0.008). At baseline, believing that medications in general were overused in healthcare was negatively associated with adherence to DOAC (β = -1.5, 95%C.I: -2.7, -0.3; p = 0.013).

CONCLUSIONS

Although many patients who switched were adherent to therapy long-term, between 23 and 39% of patients exhibited sub-optimal adherence: these patients can be identified through their modifiable health beliefs at the time of switching.

[Pulmonary artery thrombosis: strategy of anticoagulation]

This review is devoted to the management of primary artery thrombosis (PAT). This disease was always considered only as a part of other venous thromboembolic events, in particular isolated pulmonary embolism (PE). Various studies show that PAT can develop as an independent event without concomitant damage to extra-vessels. PAT is characterized by own typical signs as primary and recurrent event that can determine special strategies of treatment. However, there are no studies devoted to this problem. We can only make some assumptions about PAT anticoagulation (AC) considering data on isolated PE comprising PAT. These data are available in PADIS-PE, ASPIRE, EINSTEIN-PE, Hokusai-VTE studies underlying modern guidelines of various societies. In the absence of studies on PAT AC these guidelines should regulate PAT AC approaches. AC is recommended in all cases of PE except isolated subsegmental PAT in ambulatory patients. Duration of AC depends on risk factors (major or minor). Anticoagulation for PAT following chronic inflammatory diseases is still disputable.

Anticoagulation Treatment in Venous Thromboembolism: Options and Optimal Duration

Venous thromboembolism (VTE), clinically presenting as deep-vein thrombosis (DVT) or pulmonary embolism (PE), constitutes a major global healthcare concern with severe complications, long-term morbidity and mortality. Although several clinical, genetic and acquired risk factors for VTE have been identified, the molecular pathophysiology and mechanisms of disease progression remain poorly understood. Anticoagulation has been the cornerstone of therapy for decades, but there still are uncertainties regarding primary and secondary VTE prevention, as well as optimal therapy duration. In this review we discuss the role of factor Xa in coagulation cascade and the different choices of anticoagulation therapy based on patients' predisposing risk factors and risk of event recurrence. Further, we compare newer agents to traditional anticoagulation treatment, based on most recent studies and guidelines.

Long-term risk of major bleeding after discontinuing anticoagulation for unprovoked venous thromboembolism: a systematic review and meta-analysis

BACKGROUND

The long-term risk of major bleeding after discontinuing anticoagulant therapy for a first unprovoked venous thromboembolism (VTE) is uncertain.

OBJECTIVES

To determine the incidence of major bleeding up to 5 years after discontinuing anticoagulation for a first unprovoked VTE.

METHODS

We searched MEDLINE, EMBASE, and Cochrane CENTRAL (from inception to January 2021) to identify relevant randomized controlled trials (RCTs) and prospective cohort studies reporting major bleeding after discontinuing anticoagulation in patients with a first unprovoked VTE who had completed ≥3 months of initial treatment. Unpublished data on major bleeding events and person-years were obtained from authors of included studies to calculate study-level incidence rates. Random-effects meta-analysis was used to pool results across studies.

RESULTS

Of 1123 records identified by the search, 20 studies (17 RCTs) and 8740 patients were included in the analysis. During 13 011 person-years of follow-up after discontinuing anticoagulation, the pooled incidence of major bleeding (n=41) and fatal bleeding (n=7) per 100 person-years was 0.35 (95% confidence interval [CI], 0.20-0.54) and 0.09 (95% CI, 0.05-0.15). The 5-year cumulative incidence of major bleeding was of 1.0% (95% CI, 0.4%-2.4%). The case-fatality rate of major bleeding after discontinuing anticoagulation was 19.9% (95% CI, 10.6%-31.1%).

CONCLUSIONS

Patients with a first unprovoked VTE have a non-trivial risk of major bleeding once anticoagulants are discontinued. Estimates from this study can help clinicians counsel patients about the incremental risk of major bleeding with extended anticoagulation to guide decision making about treatment duration for unprovoked VTE.

Effects of statins in primary and secondary prevention for venous thromboembolism events: A meta analysis

OBJECTIVE

The associations between statins use and incidence or recurrence of venous thromboembolism (VTE) are controversial. We aimed to conduct a meta-analysis to reconcile the conflicting results.

METHODS

We searched PubMed, Embase and Cochrane Library for studies published from database inception until May 31, 2021. Cohort studies and Randomized Controlled Trials that reported incidence or recurrence of VTE using statins compared with placebo or non-statins were included for meta-analysis.

RESULTS

A total of 43 studies comprising over 8.6 million participants were included for analysis. The median follow-up duration was 38.1 months. Compared with no statins treatment, statins appeared to have a protective effect in primary prevention of VTE (RR 0.78, 95% CI 0.72-0.85), but significant heterogeneity was found among included studies (I² = 81%). Statins was also associated with a 26% reduced risk of recurrent VTE (RR 0.74, 95% CI 0.70-0.78), even in patients receiving anticoagulant therapy (RR 0.77, 95% CI 0.65-0.92). In patients with a history of VTE, statins was associated with a reduced risk of bleeding and all cause mortality. The NNT of statins to prevent one case of VTE in the cancer population, and one case of recurrent VTE in patients with a history of VTE was 103.1 and 90.7 person-years respectively.

CONCLUSION

In high-risk patients, statins treatment may reduce the incidence of VTE. Statins can also reduce the risk of recurrent VTE and all-cause mortality in patients with a history of VTE.

Venous Thromboembolism for the Practicing Cardiologist

Venous thromboembolism (VTE), encompassing pulmonary embolism (PE) and deep vein thrombosis (DVT), is encountered commonly. Acute PE may present as a high-risk cardiovascular emergency, and acute DVT can cause acute and chronic vascular complications. The goal of this review is to ensure that cardiologists are comfortable managing VTE-including risk stratification, anticoagulation therapy, and familiarity with primary reperfusion therapy. Clinical assessment and determination of degree of right ventricular dysfunction are critical in initial risk stratification of PE and determination of parenteral versus oral anticoagulation therapy. Direct oral anticoagulants have emerged as preferred first-line oral anticoagulation strategy in VTE scenarios.

Long-term risk of recurrent venous thromboembolism among patients receiving extended oral anticoagulant therapy for first unprovoked venous thromboembolism: A systematic review and meta-analysis

BACKGROUND

The long-term risk for recurrent venous thromboembolism (VTE) during extended anticoagulation for a first unprovoked VTE is uncertain.

OBJECTIVES

To determine the incidence of recurrent VTE during extended anticoagulation of up to 5 years in patients with a first unprovoked VTE.

METHODS

MEDLINE, EMBASE, and the Cochrane CENTRAL were searched to identify randomized trials and prospective cohort studies reporting recurrent VTE among patients with a first unprovoked VTE who were to receive anticoagulation for a minimum of six additional months after completing ≥3 months of initial treatment. Unpublished data on number of recurrent VTE and person-years, obtained from authors of included studies, were used to calculate study-level incidence rate, and random-effects meta-analysis was used to pool results.

RESULTS

Twenty-six studies and 15 603 patients were included in the analysis. During 11 631 person-years of follow-up, the incidence of recurrent VTE and fatal pulmonary embolism per 100 person-years was 1.41 (95% CI, 1.03-1.84) and 0.09 (0.04-0.16), with 5-year cumulative incidences of 7.1% (3.0%-13.2%) and 1.2% (0.4%-4.6%), respectively. The incidence of recurrent VTE was 1.08 (95% CI, 0.77-1.44) with direct oral anticoagulants and 1.55 (1.01-2.20) with vitamin K antagonists. The case-fatality rate of recurrent VTE was 4.9% (95% CI, 2.2%-8.7%).

CONCLUSIONS

In patients with a first unprovoked VTE, the long-term risk of recurrent VTE during extended anticoagulation is low but not negligible. Thus, clinicians and patients should be aware of this risk and take appropriate and timely action in case of suspicion of recurrent VTE. Estimates from this study can be used to advise patients on what to expect while receiving extended anticoagulation, and estimate the net clinical benefit of extended treatment to guide long-term management of unprovoked VTE.

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.

Long-Term Risk for Major Bleeding During Extended Oral Anticoagulant Therapy for First Unprovoked Venous Thromboembolism : A Systematic Review and Meta-analysis

BACKGROUND

The long-term risk for major bleeding in patients receiving extended (beyond the initial 3 to 6 months) anticoagulant therapy for a first unprovoked venous thromboembolism (VTE) is uncertain.

PURPOSE

To determine the incidence of major bleeding during extended anticoagulation of up to 5 years among patients with a first unprovoked VTE, overall, and in clinically important subgroups.

DATA SOURCES

MEDLINE, Embase, and the Cochrane Central Register of Controlled Trials from inception to 23 July 2021.

STUDY SELECTION

Randomized controlled trials (RCTs) and prospective cohort studies reporting major bleeding among patients with a first unprovoked VTE who were to receive oral anticoagulation for a minimum of 6 additional months after completing at least 3 months of initial anticoagulant treatment.

DATA EXTRACTION

Two reviewers independently abstracted data and assessed study quality. Unpublished data required for analyses were obtained from authors of included studies.

DATA SYNTHESIS

Among the 14 RCTs and 13 cohort studies included in the analysis, 9982 patients received a vitamin K antagonist (VKA) and 7220 received a direct oral anticoagulant (DOAC). The incidence of major bleeding per 100 person-years was 1.74 events (95% CI, 1.34 to 2.20 events) with VKAs and 1.12 events (CI, 0.72 to 1.62 events) with DOACs. The 5-year cumulative incidence of major bleeding with VKAs was 6.3% (CI, 3.6% to 10.0%). Among patients receiving either a VKA or a DOAC, the incidence of major bleeding was statistically significantly higher among those who were older than 65 years or had creatinine clearance less than 50 mL/min, a history of bleeding, concomitant use of antiplatelet therapy, or a hemoglobin level less than 100 g/L. The case-fatality rate of major bleeding was 8.3% (CI, 5.1% to 12.2%) with VKAs and 9.7% (CI, 3.2% to 19.2%) with DOACs.

LIMITATION

Data were insufficient to estimate incidence of major bleeding beyond 1 year of extended anticoagulation with DOACs.

CONCLUSION

In patients with a first unprovoked VTE, the long-term risks and consequences of anticoagulant-related major bleeding are considerable. This information will help inform patient prognosis and guide decision making about treatment duration for unprovoked VTE.

PRIMARY FUNDING SOURCE

Canadian Institutes of Health Research. (PROSPERO: CRD42019128597).

National guidelines on the management of venous thromboembolism: Joint guideline of the Turkish Society of Cardiovascular Surgery, National Society of Vascular and Endovascular Surgery, and Phlebology Society

These evidence-based guidelines from the Turkish Society of Cardiovascular Surgery, National Society of Vascular and Endovascular Surgery, and Phlebology Society intend to support clinicians in best decisions regarding the treatment of venous thromboembolism (VTE). The Editor was selected by the three national societies and was tasked with the recruitment of the recognized panel. All financial support was solely derived from the sponsoring societies without the direct involvement of industry or other external stakeholders. The panel prioritized clinical questions and outcomes according to their importance for clinicians in terms of VTE. The panel agreed on 42 recommendations under 15 headings for the diagnosis, initial management, secondary prevention of VTE, and treatment of recurrent VTE events. Important recommendations included the use of ultrasonography, preference for home treatment over hospital treatment for uncomplicated VTE, preference for direct oral anticoagulants (DOACs) over vitamin K antagonists for primary treatment of cancer and non-cancer-related VTE, extended or indefinite anticoagulation with DOACs in selected high-risk patients. Early catheter-directed thrombectomy was recommended in only young symptomatic patients with a diagnosis of fresh iliofemoral deep vein thrombosis.

Impact of Systemic Atherosclerosis on Clinical Characteristics and Short-term Outcomes in Patients with Deep Venous Thrombosis or Thrombophlebitis

BACKGROUND

Venous thromboembolism (VTE) and atherosclerosis are accompanied by substantial cardiovascular mortality; links between both disease entities were reported. We aimed to investigate the impact of systemic atherosclerosis on adverse outcomes in patients with deep venous thrombosis or thrombophlebitis (DVT) and to identify differences in DVT patients with and without systemic atherosclerosis.

METHODS

The German nationwide inpatient sample was used for this analysis. Patients admitted for DVT were included in this study and stratified by systemic atherosclerosis (composite of coronary artery disease, myocardial infarction, ischemic stroke, and/or atherosclerotic arterial diseases). We compared DVT patients with (DVT+Athero) and without (DVT-Athero) systemic atherosclerosis and analysed the impact of systemic atherosclerosis on adverse outcomes.

RESULTS

Overall, 489,679 patients with DVT (55.7% females) were included in this analysis. Among these, 53,309 (10.9%) were coded with concomitant systemic atherosclerosis with age-dependent incline. Concomitant PE (4.1% vs.3.8%, P=0.001) was more frequently in DVT-Athero and risk for PE in DVT patients was independently associated with absence of systemic atherosclerosis (OR 0.87 [95%CI 0.83-0.91], P<0.001). In-hospital mortality (3.4% vs.1.4%, P<0.001) and adverse in-hospital events (2.2% vs.0.8%,P<0.001) were more prevalent in DVT+Athero compared to DVT-Athero; both, in-hospital mortality (OR 1.52 [95%CI 1.41-1.63], P<0.001) and adverse in-hospital events (OR 1.49 [95%CI 1.40-1.58], P<0.001) were affected independently of sex, age and comorbidities by systemic atherosclerosis.

CONCLUSIONS

Systemic atherosclerosis in DVT patients was accompanied by poorer outcomes. Systemic atherosclerosis was associated with higher bleeding rate and with isolated DVT (without concomitant PE).

Extended-Duration Low-Intensity Apixaban to Prevent Recurrence in Patients with Provoked Venous Thromboembolism and Enduring Risk Factors: Rationale and Design of the HI-PRO Trial

Patients with acute venous thromboembolism (VTE) in the setting of transient provoking factors are typically treated with short-term anticoagulation. However, the risk of recurrence may be increased in the presence of enduring risk factors. In such patients, the optimal duration of treatment remains uncertain. HI-PRO is a single-center, double-blind randomized trial. Patients with deep vein thrombosis (DVT) or pulmonary embolism (PE) following a major provoking factor, including major surgery or major trauma, who completed at least 3 months of standard-dose therapeutic anticoagulation and have at least one enduring risk factor (such as obesity or heart failure) will be considered for inclusion. Patients will be randomized to apixaban 2.5 mg twice daily or placebo for 12 months. The primary efficacy outcome will be symptomatic recurrent VTE-a composite of DVT and/or PE at 12 months after randomization. Secondary efficacy outcomes include a composite of death due to cardiovascular causes, nonfatal myocardial infarction, stroke or systemic embolism, major adverse limb events, or coronary or peripheral ischemia requiring revascularization at 12 months, and individual components of these outcomes. The primary safety outcome is major bleeding according to the International Society on Thrombosis and Haemostasis definition. The study plans to enroll 600 patients (300 per arm) to have 80% power for detecting a 75% relative risk reduction in the primary outcome. Active recruitment began in March 2021. HI-PRO will provide clinically meaningful data on whether patients with provoked VTE and enduring risk factors have fewer adverse clinical outcomes if prescribed low-intensity extended-duration anticoagulation.

Eighty years of oral anticoagulation: Learning from history

In the year 2021 we celebrate the 80th anniversary of the first clinical use of vitamin K antagonists (VKAs), the mainstay of prevention and long-term treatment of thromboembolic disease. The discovery and development of oral anticoagulants is one of the most important chapters in the history of medicine, a goal pursued by physicians trying to combat the clinical manifestations of thrombosis since ancient times. Until the last decade, VKAs were the only oral anticoagulants available and used in clinical practice. Today, their clinical use has progressively shrunk, as the non-vitamin K antagonist oral anticoagulants (NOACs) are increasingly replacing VKAs in various conditions after the successful completion of several large randomized controlled trials. Currently, new research is tackling upstream components of the intrinsic pathway - particularly factor XI and factor XII - for the development of new, even safer anticoagulants promising to reduce bleeding without compromising efficacy. This review highlights the evolution of oral anticoagulant therapy tracing the key stages of a long and fascinating history that has unfolded from the first part of the twentieth century until today, indeed an intriguing journey where serendipity is intertwined with the tenacious work of many researchers.

Efficacy and safety of direct-acting oral anticoagulants compared to vitamin K antagonists in COVID-19 outpatients with cardiometabolic diseases

BACKGROUND

It remains uncertain if prior use of oral anticoagulants (OACs) in COVID-19 outpatients with multimorbidity impacts prognosis, especially if cardiometabolic diseases are present. Clinical outcomes 30-days after COVID-19 diagnosis were compared between outpatients with cardiometabolic disease receiving vitamin K antagonist (VKA) or direct-acting OAC (DOAC) therapy at time of COVID-19 diagnosis.

METHODS

A study was conducted using TriNetX, a global federated health research network. Adult outpatients with cardiometabolic disease (i.e. diabetes mellitus and any disease of the circulatory system) treated with VKAs or DOACs at time of COVID-19 diagnosis between 20-Jan-2020 and 15-Feb-2021 were included. Propensity score matching (PSM) was used to balance cohorts receiving VKAs and DOACs. The primary outcomes were all-cause mortality, intensive care unit (ICU) admission/mechanical ventilation (MV) necessity, intracranial haemorrhage (ICH)/gastrointestinal bleeding, and the composite of any arterial or venous thrombotic event(s) at 30-days after COVID-19 diagnosis.

RESULTS

2275 patients were included. After PSM, 1270 patients remained in the study (635 on VKAs; 635 on DOACs). VKA-treated patients had similar risks and 30-day event-free survival than patients on DOACs regarding all-cause mortality, ICU admission/MV necessity, and ICH/gastrointestinal bleeding. The risk of any arterial or venous thrombotic event was 43% higher in the VKA cohort (hazard ratio 1.43, 95% confidence interval 1.03-1.98; Log-Rank test p = 0.029).

CONCLUSION

In COVID-19 outpatients with cardiometabolic diseases, prior use of DOAC therapy compared to VKA therapy at the time of COVID-19 diagnosis demonstrated lower risk of arterial or venous thrombotic outcomes, without increasing the risk of bleeding.

Direct oral anticoagulants versus vitamin K antagonists in patients with antiphospholipid syndrome: systematic review and meta-analysis

Background

Despite vitamin K antagonists (VKA) being the gold standard in the prevention of thromboembolic events in antiphospholipid syndrome (APS), non-vitamin K antagonists oral anticoagulants/direct oral anticoagulants (DOACs) have been used off-label.

Objective

We aimed to perform a systematic review comparing DOACs to VKA regarding prevention of thromboembolic events, occurrence of bleeding events and mortality in patients with APS.

Methods

An electronic database search was performed through MEDLINE, CENTRAL and Web of Science. After data extraction, we pooled the results using risk ratio (RR) and 95% CI. Heterogeneity was assessed using the I². The outcomes considered were all thromboembolic events as primary, and major bleeding, all bleeding events and mortality as secondary. Evidence confidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation methodology.

Results

We included 7 studies and a total of 835 patients for analyses. Thromboembolic events were significantly increased in DOACs arm, compared with VKA—RR 1.69, 95% CI 1.09 to 2.62, I²—24%, n=719, 6 studies. In studies using exclusively rivaroxaban, which was the most representative drug in all included studies, the thromboembolic risk was increased threefold (RR 3.36, 95% CI 1.53 to 7.37). The risks of major bleeding, all bleeding events and mortality were not significantly different from control arm. The grade of certainty of our results is very low.

Conclusions

Current evidence suggests DOACs use, particularly rivaroxaban, among patients with APS, is less effective than VKA since it is associated with 69% increased risk of thromboembolic events.

Trial registration number

CRD42020216178.