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

Idarucizumab Reverses Dabigatran Anticoagulant Activity in Healthy Chinese Volunteers: A Pharmacokinetics, Pharmacodynamics, and Safety Study

INTRODUCTION

Idarucizumab is a humanized monoclonal antibody fragment that specifically binds to dabigatran with high affinity and reverses its anticoagulant effect. This study investigated the pharmacokinetics (PK) and pharmacodynamics (PD) of idarucizumab in healthy Chinese subjects at steady state of dabigatran and explored the effect of idarucizumab on PK and PD of dabigatran.

METHODS

Twelve subjects received dabigatran etexilate treatment alone (220 mg twice daily, b.i.d., oral). After a washout period, the 12 subjects again received dabigatran etexilate (220 mg b.i.d., oral) and idarucizumab (2.5 + 2.5 g, intravenous) 2 h after the last administration of dabigatran etexilate.

RESULTS

The geometric mean (gMean) values of area under the plasma concentration-time curve (AUC_0-∞) and maximum concentration (C_max) were 44,200 nmol h/L and 30,900 nmol/L, respectively. An amount of 35.3 μmol of idarucizumab, corresponding to 33.8% of the total dose, was excreted by urine over 72 h. The area under the effect (AUEC_above,2-12) in the presence and absence of idarucizumab was close to zero for all coagulation parameters, diluted thrombin time (dTT), ecarin clotting time (ECT), activated partial thromboplastin time (aPTT), and thrombin time (TT), which indicated the reversal of dabigatran anticoagulation by idarucizumab. There were no serious adverse events reported in this study. No subject tested positive for anti-idarucizumab antibodies.

CONCLUSION

Idarucizumab was well tolerated and no subject tested positive for anti-idarucizumab antibodies in this study. PK and PD of idarucizumab in healthy Chinese subjects at a steady state of dabigatran were comparable with those in Japanese and Caucasian subjects.

CLINICAL REGISTRATION

ClinicalTrials.gov Identifier No. NCT03086356.

Extended DOAC therapy in patients with VTE and potential risk of recurrence: A systematic review and meta-analysis

BACKGROUND

Guidelines recommend at least 3 months of anticoagulation for venous thromboembolism (VTE). Evidence supporting indefinite anticoagulation exists in certain conditions; however, for many patients, uncertainty regarding when to discontinue anticoagulation persists.

OBJECTIVE

We aimed to investigate the efficacy and safety of extended direct oral anticoagulants (DOAC) therapy in patients with VTE and clinical uncertainty regarding extended anticoagulation.

METHODS

We searched EMBASE, MEDLINE, PubMed, and Cochrane Central Register of Controlled Trials databases for randomized control trials examining extended anticoagulation with DOACs as compared to non-extended therapy for the treatment of VTE.

RESULTS

Of 560 citations identified by the search, three studies were eligible. Extended anticoagulation reduced VTE recurrence (relative risk [RR] 0.18, 95% confidence interval [CI] 0.12 to 0.25), and mortality (RR 0.39, 95% CI 0.19 to 0.80) with a low total number of deaths in the DOAC group (n = 12) versus placebo (n = 18). Extended anticoagulation increased clinically relevant non-major bleedings (RR 2.51, 95% CI 1.37 to 4.59). There was no difference in rates of major bleeding (RR 1.87, 95% CI 0.19 to 17.85); however, there was a low number of major bleeding events in both DOAC (n = 9) and placebo groups (n = 4). The results were mostly driven by one study (AMPLIFY-EXT), with significant heterogeneity between studies noticed when assessing bleeding outcomes.

CONCLUSION

Extended DOAC therapy for 1 year in patients with clinical uncertainty for ongoing anticoagulation can reduce VTE recurrence and mortality; however, it could increase clinically relevant non-major bleeding events.

Mortality risk associated with venous thromboembolism: a systematic review and Bayesian meta-analysis

BACKGROUND

Venous thromboembolism is associated with increased mortality risk in some populations, but how frequently it is a direct cause of death is unclear. We used data from venous thromboembolism prevention trials to evaluate the causal effect of venous thromboembolism reduction on mortality.

METHODS

We did a systematic review and meta-analysis of randomised controlled trials (RCTs) evaluating venous thromboembolism prevention. We searched MEDLINE, Embase, PubMed, and Web of Science starting from Jan 1, 1993, to March 19, 2018. We included studies of patients who were at elevated risk of venous thromboembolism and were randomly assigned to either anticoagulant or antiplatelet therapy versus placebo or no treatment. We excluded studies with an active control agent (which might mitigate the lethality of venous thromboembolism) and those for which mortality data were unavailable. We modelled heterogeneity in a Bayesian framework, taking overall mortality as a primary endpoint, and pulmonary embolism, fatal pulmonary embolism, and major bleeding as secondary endpoints. We focused our analyses on studies reporting statistically significant effects of prevention on venous thromboembolism endpoints. We report treatment effects as median risk ratios (RRs), wherein a null effect equals 1, with 95% credible intervals (CrIs). This meta-analysis was registered with PROSPERO, CRD42018089697.

FINDINGS

From 4229 studies screened, we identified 86 eligible RCTs; 52, with data from over 70 000 patients, were positive, with significantly increased venous thromboembolism risk in patients in control groups versus treatment groups (RR 2·74, 95% CrI 2·32-3·31, p<0·0001). The meta-analysis established that the causal effect of venous thromboembolism prevention on mortality was null (control group mortality was 3391 [9·8%] of 34 537 patients; treatment group mortality was 3498 [9·8%] of 35 795 patients [RR 1·01, 95% CrI 0·97-1·06; p=0·58]) with low heterogeneity (τ 0·02, 95% CrI 0·00-0·07, p=0·89). Patients in control groups had more pulmonary embolism (RR 2·22, 95% CrI 1·78-2·89, p<0·0001) and fatal pulmonary embolism (1·58, 1·14-2·19, p=0·01), but less major bleeding (0·60, 0·47-0·75, p<0·0001) than those in treatment groups. A meta-analysis with the additional 34 negative studies yielded similar results for all endpoints except fatal pulmonary embolism, where evidence of an effect was weaker (1·42, 1·05-1·91, p=0·02).

INTERPRETATION

The perception that venous thromboembolism is a common cause of mortality should be revised considering the null effect of venous thromboembolism prevention on mortality. Our findings call into question the use of composite endpoints in venous thromboembolism-prevention trials and provide rationale for de-escalation trials.

FUNDING

None.

Safety of dabigatran etexilate for the secondary prevention of venous thromboembolism in children

This open-label, single-arm, prospective cohort trial is the first phase 3 safety study to describe outcomes in children treated with dabigatran etexilate for secondary venous thromboembolism (VTE) prevention. Eligible children aged 12 to <18 years (age stratum 1), 2 to <12 years (stratum 2), and >3 months to <2 years (stratum 3) had an objectively confirmed diagnosis of VTE treated with standard of care (SOC) for ≥3 months, or had completed dabigatran or SOC treatment in the DIVERSITY trial (NCT01895777) and had an unresolved clinical thrombosis risk factor requiring further anticoagulation. Children received dabigatran for up to 12 months, or less if the identified VTE clinical risk factor resolved. Primary end points included VTE recurrence, bleeding events, and mortality at 6 and 12 months. Overall, 203 children received dabigatran, with median exposure being 36.3 weeks (range, 0-57 weeks); 171 of 203 (84.2%) and 32 of 203 (15.8%) took capsules and pellets, respectively. Overall, 2 of 203 children (1.0%) experienced on-treatment VTE recurrence, and 3 of 203 (1.5%) experienced major bleeding events, with 2 (1.0%) reporting clinically relevant nonmajor bleeding events, and 37 (18.2%) minor bleeding events. There were no on-treatment deaths. On-treatment postthrombotic syndrome was reported for 2 of 162 children (1.2%) who had deep vein thrombosis or central-line thrombosis as their most recent VTE. Pharmacokinetic/pharmacodynamic relationships of dabigatran were similar to those in adult VTE patients. In summary, dabigatran showed a favorable safety profile for secondary VTE prevention in children aged from >3 months to <18 years with persistent VTE risk factor(s). This trial was registered at www.clinicaltrials.gov as #NCT02197416.

Anticoagulation in Deep Venous Thrombosis: Current Trends in the Era of Non- Vitamin K Antagonists Oral Anticoagulants

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Anticoagulation therapy is the cornerstone of treatment in acute vein thrombosis (DVT) and it aims to reduce symptoms, thrombus extension, DVT recurrences, and mortality. The treatment for DVT depends on its anatomical extent, among other factors. Anticoagulation therapy for proximal DVT is clearly recommended (at least for 3 months), while AT for isolated distal DVT should be considered, especially in the presence of high thromboembolic risk factors. The optimal anticoagulant and duration of therapy are determined by the clinical assessment, taking into account the thromboembolic and bleeding risk in each patient in a case-by-case decision making. Non-Vitamin K antagonists oral anticoagulants (NOACs) were a revolution in the anticoagulation management of DVT. Nowadays, NOACs are considered as first-line therapy in the anticoagulation therapy for DVT and are recommended as the preferred anticoagulant agents by most scientific societies. NOACs offer a simple route of administration (oral agents), a rapid onset-offset of their action along with a good efficacy and safety profile in comparison with Vitamin K Antagonists (VKAs). However, there are issues about their efficacy and safety profile in specific populations with high thromboembolic and bleeding risks, such as renal failure patients, active-cancer patients, and pregnant women, in which VKAs and heparins were the standard care of treatment. Since the available data are promising for the use of NOACs in end-stage chronic kidney disease and cancer patients, several ongoing randomized trials are currently trying to solve that issues and give evidence about the safety and efficacy of NOACs in these populations.

Non-Vitamin K Antagonist Oral Anticoagulants in Pulmonary Embolism: An Overview of Systematic Reviews

Background:

Anticoagulation in patients with pulmonary embolism.

Objective:

To identify how non-vitamin K antagonist oral anticoagulants are associated with multiple outcomes in patients with pulmonary embolism.

Methods:

We performed a systematic search of systematic reviews via multiple electronic databases from inception to August 19th, 2019, without language restriction. Two authors independently extracted data and assessed the methodological quality of the included systematic reviews using the ROBIS tool.

Results:

We found twelve systematic reviews. Eleven SRs collected their data from randomized clinical trials and one from observational studies. All the included studies were published between 2014 and 2019 in English. The methodological quality of the 12 systematic reviews was low to high. None of the systematic reviews, which are included in our overview of systematic reviews, has evaluated the overall quality of evidence outcome using the Grading of Recommendations Assessments, Development and Evaluation (GRADE) approach.

Conclusion:

This is the first effort to summarize evidence about non-vitamin K antagonist oral anticoagulants in an overview of systematic reviews focusing exclusively on patients with pulmonary embolism. The evidence suggests that the non-vitamin K antagonist oral anticoagulants seem to be more effective and safer than a dualdrug approach with LMWH- VKA.

Comparative Effects Between Direct Oral Anticoagulants for Acute Venous Thromboembolism: Indirect Comparison From Randomized Controlled Trials

Background: There is no direct comparison from clinical trials amongst the direct oral anticoagulants (DOACs) in patients with acute venous thromboembolism (VTE), leaving an evidence gap in decision-making regarding the choice of a DOAC.

Methods: We performed a systematic review for an indirect comparison from randomized controlled trials (RCTs) for comparative effects amongst DOACs in the patients with acute VTE.

Results: A total of 16 RCTs were included for analyses, among which three for dabigatran (n = 7,963 patients), six rivaroxaban (n = 17,935), five apixaban (n = 12,823), and two edoxaban (n = 9,286). There was no significant difference in risk of recurrent VTE (evidence quality: low) and major bleeding (evidence quality: very low) for treatment effects between the four DOACs. Albeit non-significantly, apixaban seemed to have a lowest risk of major bleeding while rivaroxaban had a smallest risk of VTE. Although in general all the included trials were comparable, data from the included trials indicated that the assumption of transitivity may be challenged. Further methodological research including simulation studies, using a net-benefit or benefit-harm approach, running ranking probability analysis, and developing decision aids with machine-learning may be a worthwhile endeavor to help with the choice of DOACs in patients with acute VTE.

Conclusions: To conclude, based on results from the indirect comparison no significant difference in the efficacy and safety was found among the DOACs in patients with acute VTE. More evidence from direct comparative trials is needed to further inform the choice of DOACs in patients with acute VTE.

Treatment of Acute Venous Thromboembolism

"Acute venous thromboembolism is a common disease seen by nearly all hospitalists. The advent of low molecular weight heparin (LMWH) several decades ago ushered in the era of early hospital discharge and home treatment. More recently, the direct oral anticoagulants (DOACs) have further simplified outpatient treatment and some offer treatment without parenteral therapy. Use of DOACs for cancer-associated venous thromboembolism is emerging and is a welcome evolution of care to spare oncologic patients the burden of daily LMWH injections."

Long-term treatment of venous thromboembolism

The most important decision in the long-term treatment of venous thromboembolism (VTE) is how long to anticoagulate. VTE provoked by a reversible risk factor, or a first unprovoked isolated distal deep vein thrombosis (DVT), generally should be treated for 3 months. VTE provoked by a persistent or progressive risk factor (eg, cancer), or a second unprovoked proximal DVT or PE, is generally treated indefinitely. First unprovoked proximal DVT or PE may be treated for 3 to 6 months or indefinitely. Male sex, presentation as PE (particularly if concomitant proximal DVT), a positive d-dimer test after stopping anticoagulation, an antiphospholipid antibody, low risk of bleeding, and patient preference favor indefinite anticoagulation. The type of indefinite anticoagulation is of secondary importance. Low-dose oral Xa inhibitors are convenient and are thought to have a lower risk of bleeding; they are less suitable if there is a higher risk for recurrence. For cancer-associated VTE, we now prefer full-dose oral Xa inhibitors over low-molecular-weight heparin, with gastrointestinal lesions being a relative contraindication. Graduated compression stockings are not routinely indicated after DVT, but are encouraged if there is persistent leg swelling or if a trial of stockings improves symptoms. Medications have a limited role in the treatment of postthrombotic syndrome. After PE, patients should have clinical surveillance for chronic thromboembolic pulmonary hypertension (CTEPH), with ventilation-perfusion scanning and echocardiography being the initial diagnostic tests if CTEPH is a concern. Patients with CTEPH and other symptomatic patients with extensive residual perfusion defects should be evaluated for endarterectomy, balloon pulmonary angioplasty, or vasodilator therapies.

Rational and design of the China Pulmonary Thromboembolism Registry Study (CURES): A prospective multicenter registry

BACKGROUND

Epidemiological data on pulmonary embolism (PE) in China needs to be updated and reported. The China Pulmonary Thromboembolism Registry Study (CURES) is designed to provide the cross-sectional spectrum and chronological trends of PE in China, as well as to reveal the intrinsic etiology and pathogenesis of the disease.

METHODS AND DESIGN

The CURES is an ongoing large prospective multicenter registry, which was originally initiated in January 2009 via enrolling suspected or confirmed PE or PE with DVT (deep venous thrombosis) patients and assessed their in-hospital outcomes. As of July 2011, in order to determine the PE-relevant short-term outcomes, enrolled participants were followed-up for at least three months in a longitudinal manner. Since August 2016, with the launch and development of precision medicine research scheme in China, the main principle investigators of CURES decided to collect enrolled patients' blood samples with regular follow-ups every three or six months for at least two years (for long-term outcomes). Up to 31 December 2019, the CURES has enrolled 14,937 eligible patients and collected 1500 blood samples of patients from 100 medical centers in the China PE-DVT network. The study protocol has been approved by the China-Japan Friendship Hospital ethics committee, and all collaborating centers received approvals from their local ethics committee. All patients provided written or verbal informed consent to their participation.

CONCLUSIONS

Findings of the CURES will be valuable for revealing the natural history of PE, and facilitating better disease management in China. Registration Number inClinicalTrials.gov:NCT02943343.

Treatment of deep vein thrombosis of the lower extremities

Deep vein thrombosis of the lower extremities is a common condition that should be treated appropriately given the possibility that it could lead to an ultimately fatal complication, as well as to a post-thrombotic syndrome that is in some cases disabling. The current treatment for this condition is differentiated into an acute phase, a long-term therapy and occasionally an extended therapy, which not only has defined objectives but also uses various drugs and even varying dosages for each drug. We describe the therapeutic anticoagulation options in each of these treatment phases and some of the treatments (thrombolysis, insertion of an inferior vena cava filter, surgery) that can play a role in certain conditions.

Antiphospholipid Syndrome Committee of the Brazilian Society of Rheumatology position statement on the use of direct oral anticoagulants (DOACs) in antiphospholipid syndrome (APS)

BACKGROUND

The term Direct Oral Anticoagulants (DOACs) refers to a group of drugs that inhibit factor Xa or thrombin. Even though their use for treating different thrombotic or prothrombotic conditions is increasing recently, there is no compelling evidence indicating that those medications are safe in all antiphospholipid syndrome (APS) patients.

METHODOLOGY

To address this issue, specialists from the Antiphospholipid Syndrome Committee of the Brazilian Society of Rheumatology performed a comprehensive review of the literature regarding DOACs use in APS to answer the three following questions: (1) potential mechanisms of action of these drugs that could be relevant to APS pathogenesis, (2) DOACs interference on lupus anticoagulant testing, and (3) the efficacy of DOACs in APS.

POSITION STATEMENT

After critically reviewing the relevant evidence, the authors formulated 8 Position Statements about DOACs use in APS.

CONCLUSION

DOACs should not be routinely used in APS patients, especially in those with a high-risk profile (triple positivity to aPL, arterial thrombosis, and recurrent thrombotic events). In addition, DOACs interferes with LA testing, leading to false-positive results in patients investigating APS.

Direct-acting oral anticoagulant use at extremes of body weight: Literature review and recommendations

Purpose

To review the literature on treatment of venous thromboembolism (VTE) and prevention of cardioembolic stroke with direct-acting oral anticoagulants (DOACs) in low- and high-body-weight patients and to make recommendations regarding agent selection and dosing in these patient populations.

Summary

The selection and optimal dosing of DOACs in low- and high-body-weight patients has not yet been fully elucidated by clinical trials; however, evidence suggests that issues of both safety and efficacy in patients at the extremes of body weight may warrant careful consideration when selecting a DOAC for such patients. This review provides a thorough discussion of the use of DOACs in the treatment of VTE and prevention of cardioembolic stroke in patients at the extremes of body weight and provides guidance regarding agent selection.

Conclusion

While the published evidence on use of DOACs in patients at extremes of body weight is sparse, apixaban and rivaroxaban appear to have the most favorable safety and efficacy profiles. Edoxaban and dabigatran should be avoided.

Fatigue after initiating rivaroxaban for venous thromboembolism

BACKGROUND

Rivaroxaban was the first new oral anticoagulant approved for treatment of venous thromboembolism (VTE). Clinical trials have shown that rivaroxaban is noninferior to conventional anticoagulation for VTE in efficacy and safety. Increased fatigue after the initiation of rivaroxaban has been observed in clinical practice, but data on this potential side effect are lacking.

OBJECTIVE

The study aimed to evaluate development of fatigue in patients treated for VTE, comparing rivaroxaban to other anticoagulants.

METHODS

Patients were prospectively recruited after a diagnosis of VTE. The Fatigue Questionnaire was used to determine the level of fatigue at baseline, at 3 weeks of treatment, and either at 1 month after the discontinuation of treatment if the treatment was discontinued after 3 months or at 6 months if treatment was continued beyond this time. Data was analyzed by a linear mixed model.

RESULTS

A total of 126 patients were included. Mean age was 59 years; 77 (61%) were males. Fifty-seven patients (45%) were diagnosed with deep vein thrombosis, 48 (38%) with pulmonary embolism, and 21 (17%) with both. Predicted changes in fatigue scores from baseline to the last measurement were -0.007 and -2.49 for the rivaroxaban and the other-anticoagulants groups, respectively, neither of which were statistically significant. No difference was detected between rivaroxaban and the other-anticoagulants group at any time point, including subgroup analysis comparing over and under 6 months of treatment duration.

CONCLUSION

In this small study, our results suggest no increase in the level of fatigue after the initiation of treatment with rivaroxaban for VTE.

Comparative Efficacy and Safety of Sulodexide and Other Extended Anticoagulation Treatments for Prevention of Recurrent Venous Thromboembolism: A Bayesian Network Meta-analysis

Objective  This network meta-analysis (NMA) assesses the clinical comparative efficacy and safety of sulodexide versus direct-acting oral anticoagulants (DOACs), vitamin K antagonist (VKA), and aspirin in patients with an unprovoked venous thromboembolism (VTE). Methods  We conducted a literature search in MEDLINE, Embase, and Cochrane Library using both randomized controlled trials (RCTs) and observational studies. Reduction in recurrent deep venous thrombosis (r-DVT), pulmonary embolism (PE), major bleeding (MB), clinically relevant nonmajor bleeding (CRNMB) were the primary efficacy and safety outcomes. Other secondary end points were also included. We performed a fixed, random effects, and hierarchical models Bayesian NMA for each outcome. Results  We identified 18 RCTs and seven observational studies. Random models showed sulodexide is the best treatment compared with DOACs, VKA, and aspirin at reducing the risk of CRNMB, for preventing death from any cause, and VTE/PE/myocardial infarction (MI)/stroke with 0.47, 0.81, and 0.65 probabilities, respectively. In the random model sulodexide was the best treatment for reducing the risk of MB with a 0.50 probability and hierarchical model that confirmed favorable results. Random and hierarchical models showed sulodexide and DOACs to be the best treatments for reducing PE risk. Sulodexide was more effective than aspirin for reducing r-DVT with 0.12 and less of 0.0001 probabilities, respectively. Conclusion  Sulodexide is more effective for reducing MB and CRNMB, for preventing deaths from any cause, and from VTE/PE/MI/stroke, than other treatments, for both random and hierarchical models. Sulodexide showed to be more effective than aspirin in reducing the risk of r-DVT and PE. Sulodexide's reduction in bleeding while protecting from recurrent DVT risk makes this therapeutic option an important alternative for extended anticoagulation treatment.

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

BACKGROUND & AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Extended anticoagulation after venous thromboembolism: should it be done?

Most physicians understand venous thromboembolism (VTE) to be an acute and time-limited disease. However, pathophysiological and epidemiological data suggest that in most patients VTE recurrence risk is not resolved after the first 6 months of anticoagulation. Recurrence rates are high and potentially life-threatening. In these cases, it would make sense to prolong anticoagulation for an undetermined length of time. However, what about the bleeding rates, induced by prolonged anticoagulation? Would they not outweigh the benefit of reducing the VTE recurrent risk? How long should anticoagulation be continued, and should all patients suffering from VTE be provided with extended anticoagulation? This review will address the most recent data concerning extended anticoagulation in VTE secondary prophylaxis.

The reviews of this paper are available via the supplementary material section.

Chronic Thromboembolic Pulmonary Hypertension Secondary to Thrombophilia and Incidentally Diagnosed Atrial Septal Defect

A 46-year-old man developed chronic thromboembolic pulmonary hypertension and atrial fibrillation after acute pulmonary embolism. He was found incidentally to have an isolated secundum atrial septal defect, as well as a homozygous mutation for the plasminogen activator inhibitor-1 gene. He was successfully treated with pulmonary endarterectomy and atrial septal defect repair. He has continued to do well on a regimen of dabigatran. (Level of Difficulty: Beginner.)

d-dimer is a predictor of clot resolution in patients with pulmonary thromboembolism: A retrospective cohort study

BACKGROUND

This study assessed predictors of pulmonary thromboembolism (PE) resolution and their implications for clinical outcome.

METHOD

A total of 150 patients with acute PE diagnosed by computed tomography pulmonary angiography (CTPA) were included. All patients received anticoagulant therapy for 3-6 months and were followed-up for at least 2 years. d-dimer levels in plasma were assayed at the first admission and during follow-up.

RESULTS

The rate of CTPA-confirmed PE resolution was 48.67% at 6 months, 68% at 12 months, and 78.67% at 24 months. Thirty-nine patients had recurrent thrombosis after anticoagulation therapy was stopped, whereas 93 patients had complete resolution. The initial d-dimer level positively correlated with the pulmonary artery obstruction index (PAOI) (r = 0.21; P = 0.015), but did not significantly differ between patients experiencing resolution or recurrence. In contrast, the follow-up mean d-dimer level was significantly higher in the recurrent group (P < 0.001), and this level was an independent risk factor for recurrent PE after the termination of anticoagulation treatment (OR 1.003, 95%CI 1.002 to 1.004; P < 0.001). Higher initial thromboembolic burden measured by PAOI was associated with residual thromboemboli (P = 0.004) and recurrence (P = 0.03), but was not an independent risk factor for either.

CONCLUSIONS

Elevated d-dimer is an independent risk factor for PE recurrence. A higher initial thromboembolic burden may be associated with unresolved thromboemboli or recurrence.

Anticoagulation management strategies in heart transplantation

Anticoagulation before, during, and after heart transplantation (HT) presents unique challenges to clinicians. Bleeding and thrombotic morbidity continues to affect this patient population throughout all phases of the HT journey. Reversal is commonly required since patients are commonly bridged to HT with left ventricular assist devices, which require chronic anti platelet and anticoagulation. Caution must be exercised in patients requiring cardiopulmonary bypass during surgery who are at risk of complications from heparin induced thrombocytopenia. The reported incidence of venous thromboembolism following HT is high, particularly during the first post-HT year, most likely due to surgery, biopsies, specific immunosuppression (mTOR inhibitors) and immobilization. It is crucial to maintain long-term oral anticoagulation after the first venous thromboembolism event, especially when risk factors exist. A major issue, and one for which there remains considerable debate, is the optimal treatment of such complications, particularly upper extremity venous thrombosis. For both warfarin and the thrombin inhibitors or Factor Xa inhibitors, the clinician must determine potential drug interactions based on the HT drug regimen, and then develop a patient-specific management strategy.

Which patients with unprovoked venous thromboembolism should receive extended anticoagulation with direct oral anticoagulants? A systematic review, network meta-analysis, and decision analysis

INTRODUCTION

Direct oral anticoagulants (DOACs) effectively prevent recurrent venous thromboembolism (VTE). However, it is unknown which agents should be used to prevent recurrent VTE and which patients with unprovoked VTE should receive extended anticoagulation. We therefore sought to compare the efficacy and safety among DOACs for secondary prevention of VTE. We also determined a risk-adapted threshold for initiating extended anticoagulation based on the likelihood of VTE recurrence (without treatment) and bleeding (with treatment) in patients with unprovoked VTE.

METHODS

Our systematic review of randomized controlled trials compares extended anticoagulation with DOACs to another DOAC, aspirin, or placebo for the prevention of recurrent VTE. We searched PubMed, EMBASE, and Cochrane Registry of Controlled Trials (CENTRAL) in October 2018. Our outcomes of interest were VTE recurrence, major bleeding, and all clinically relevant bleeding. We used network meta-analysis to make indirect comparisons among DOACs. We populated the threshold decision-analytic model with data from our meta-analysis to determine the risk of VTE recurrence above which the benefits of extended anticoagulation outweigh the harms compared with no treatment.

RESULTS

We included four, high-quality, randomized trials comprising 8386 participants. Low-dose apixaban, full-dose apixaban, low-dose rivaroxaban, full-dose rivaroxaban, and dabigatran reduce VTE recurrence compared with placebo (RR = 0.19, 95% CI, 0.12-0.31; RR = 0.20, 95% CI, 0.12-0.32; RR = 0.08, 95% CI, 0.03-0.27; RR = 0.14, 95% CI, 0.06-0.35; RR = 0.19, 95% CI, 0.09-0.40, respectively). No DOACs increased major bleeding risk compared with placebo. A VTE recurrence risk above 0.3% to 0.4% at approximately 1 year is the threshold to treat a patient with unprovoked VTE with extended anticoagulation (with any DOAC).

CONCLUSIONS

All DOACs exhibit comparable efficacy for the prevention of recurrent VTE. Given that the risk of VTE recurrence is much higher than the calculated threshold for treatment, extended thromboprophylaxis should be considered in all patients with unprovoked VTE who do not have increased bleeding risk.

Direct oral anticoagulants: A new chapter in anticoagulation therapy

Thromboembolic events are the leading cause of morbidity and mortality worldwide. From the second half of the 20th century, vitamin K antagonists (VKAs), warfarin and acenocoumarol, were the only anticoagulants taken orally. The major reform in anticoagulation therapy was made by the advent of direct oral anticoagulants (DOACs), about 10 years ago. Direct thrombin inhibitor (dabigatran) and direct inhibitors of factor Xa (rivaroxaban, apixaban, edoxaban, and betrixaban) have demonstrated favorable risk/benefit ratio. Compared to warfarin, DOACs are associated with a predictable pharmacokinetic profile, lower severe bleeding complications, particularly intracranial hemorrhages, and minimal drug interactions. Moreover, DOACs achieve a rapid onset of action and have shown comparable efficacy with warfarin and low molecular weight heparin (LMWH) in clinical trials. As a result, DOACs are now replacing VKAs and LMWH for many indications including stroke and systemic embolism prevention in nonvalvular atrial fibrillation, prevention, and treatment of venous thromboembolism and thromboprophylaxis following total knee/hip replacement surgery. In addition, rivaroxaban (in combination with aspirin alone or aspirin and clopidogrel) is used in the prevention of atherothrombotic events following acute coronary syndrome with elevated cardiac biomarkers. In case of severe bleeding complications under DOACs treatment, antidotes are available; idarucizumab for dabigatran reversal and andexanet alfa for rivaroxaban and apixaban.

Sustained resolution of anticoagulation related iron deficiency anemia with the use of apixaban

Successful resolution of iron deficiency anemia in the context of anticoagulation with rivaroxaban was seen when apixaban is used alternatively. Prospective cohort studies utilizing similar or different approaches are required.

Review of Direct Oral Anticoagulants and Guide for Effective Drug Utilization

Direct oral anticoagulants (DOACs) have been developed as a viable and in some cases superior alternative to warfarin. These agents have overcome some of the limitations of warfarin, which has a narrow therapeutic window and many food and drug interactions. DOACs have been demonstrated to have a more predictable and reliable pharmacology and, unlike warfarin, do not require frequent monitoring of anticoagulant effect. For these reasons, the use of DOACs is increasing. Despite the many positive attributes of these agents, limitations and contraindications do exist. An understanding of the pharmacology, indications, and contraindications is therefore crucial for effective patient management. We review the available agents to aid in effective drug utilization.

Cost-effectiveness Evaluations Among the Direct Oral Anticoagulants for the Prevention and Treatment of Venous Thromboembolism: Systematic Review

Venous thromboembolism (VTE) is associated with high recurrence, mortality, and cost burden. Direct oral anticoagulants (DOACs) are currently used for VTE treatment, and they offer more benefits over warfarin, despite being more expensive. There is no consensus on the most cost-effective DOAC agent, especially in VTE. This systematic review aims to summarize the comparative cost-effectiveness studies and their impact among DOACs in the treatment of VTE. Literature systematic review of PubMed, Embase, and EconLit was conducted in February 2018 to identify all cost-effectiveness studies of DOAC for the treatment and prevention of VTE. Two independent investigators systematically collected search results and assessed the quality of the studies. The search identified 7 articles, all of which had dabigatran and rivaroxaban as comparators, 6 of which also included apixaban, and 2 of which also had edoxaban. Results of 3 articles concluded that apixaban is a dominant strategy compared to other DOACs in terms of Incremental Cost-Effectiveness Ratio (ICER) in the treatment and prevention of recurrent VTE. One article compared rivaroxaban and dabigatran, with the latter dominating rivaroxaban in terms of ICER. Compared to other DOACs, 2 articles reported apixaban being associated with highest annual total medical cost avoidance of US$4244 and US$4440 per patient-year (ppy), respectively. One article reported that apixaban had the highest annual total medical cost differences of US$918 ppy compared to other DOACs. This systematic review demonstrates that apixaban is considered a cost-effective strategy for VTE treatment and prevention of recurrent VTE.

Discretionary Thrombophilia Test Acquisition and Outcomes in Patients With Venous Thromboembolism in a Real-World Clinical Setting

Background The value of thrombophilia test acquisition in improving risk prediction beyond clinical presentation remains unknown. We investigated the effect of thrombophilia test acquisition on venous thromboembolism (VTE) outcomes. Methods and Results We performed a retrospective cohort study of adult patients over a 15-year period (September 2001 and May 2016) with first diagnosis of VTE in a single academic medical center. Participants were identified by International Classification of Diseases, Ninth Revision (ICD-9), Current Procedural Terminology (CPT) codes and medication history. Participants with thrombophilia testing were matched to control participants without thrombophilia testing using a propensity model. Primary outcomes included recurrent VTE, anticoagulant use 12 months after the index VTE event, bleeding-related hospitalization, and death. From 3590 unique patients who met the inclusion criteria, 747 participants with VTE who underwent thrombophilia testing were matched to a control participant without testing. Tested participants were more likely to have a recurrent event (46.1% versus 28.5%; P<0.001) and an anticoagulant prescription 12 months from the index event (53.9% versus 37.1%; P<0.001) but had no significant difference in bleeding-related hospitalization (11.4% versus 11.8%; P=0.81) compared with untested participants. An abnormal thrombophilia test result, per se, did not predict recurrent VTE (47.8% versus 44.1%; P=0.13), longer duration anticoagulation (53.2% versus 54.8%; P=0.51), bleeding (11.5% versus 11.3%; P=0.70), or mortality (12.2% versus 16.1%; P=0.18) compared with participants who had normal test results. Conclusions The decision to perform thrombophilia testing, but not the test result, is associated with a high risk of recurrent VTE despite a greater likelihood of long-duration anticoagulation.

The 2018 European Heart Rhythm Association Practical Guide on the use of non-vitamin K antagonist oral anticoagulants in patients with atrial fibrillation

The current manuscript is the second update of the original Practical Guide, published in 2013 [Heidbuchel et al. European Heart Rhythm Association Practical Guide on the use of new oral anticoagulants in patients with non-valvular atrial fibrillation. Europace 2013;15:625-651; Heidbuchel et al. Updated European Heart Rhythm Association Practical Guide on the use of non-vitamin K antagonist anticoagulants in patients with non-valvular atrial fibrillation. Europace 2015;17:1467-1507]. Non-vitamin K antagonist oral anticoagulants (NOACs) are an alternative for vitamin K antagonists (VKAs) to prevent stroke in patients with atrial fibrillation (AF) and have emerged as the preferred choice, particularly in patients newly started on anticoagulation. Both physicians and patients are becoming more accustomed to the use of these drugs in clinical practice. However, many unresolved questions on how to optimally use these agents in specific clinical situations remain. The European Heart Rhythm Association (EHRA) set out to coordinate a unified way of informing physicians on the use of the different NOACs. A writing group identified 20 topics of concrete clinical scenarios for which practical answers were formulated, based on available evidence. The 20 topics are as follows i.e., (1) Eligibility for NOACs; (2) Practical start-up and follow-up scheme for patients on NOACs; (3) Ensuring adherence to prescribed oral anticoagulant intake; (4) Switching between anticoagulant regimens; (5) Pharmacokinetics and drug-drug interactions of NOACs; (6) NOACs in patients with chronic kidney or advanced liver disease; (7) How to measure the anticoagulant effect of NOACs; (8) NOAC plasma level measurement: rare indications, precautions, and potential pitfalls; (9) How to deal with dosing errors; (10) What to do if there is a (suspected) overdose without bleeding, or a clotting test is indicating a potential risk of bleeding; (11) Management of bleeding under NOAC therapy; (12) Patients undergoing a planned invasive procedure, surgery or ablation; (13) Patients requiring an urgent surgical intervention; (14) Patients with AF and coronary artery disease; (15) Avoiding confusion with NOAC dosing across indications; (16) Cardioversion in a NOAC-treated patient; (17) AF patients presenting with acute stroke while on NOACs; (18) NOACs in special situations; (19) Anticoagulation in AF patients with a malignancy; and (20) Optimizing dose adjustments of VKA. Additional information and downloads of the text and anticoagulation cards in different languages can be found on an EHRA website (www.NOACforAF.eu).

A randomised controlled trial of extended anticoagulation treatment versus standard treatment for the prevention of recurrent venous thromboembolism (VTE) and post-thrombotic syndrome in patients being treated for a first episode of unprovoked VTE (the ExACT study)

Venous thromboembolism (VTE) is prevalent and impactful, with a risk of death, morbidity and recurrence. Post-thrombotic syndrome (PTS) is a common consequence and associated with impaired quality of life (QoL). The ExACT study was a non-blinded, prospective, multicentred randomised controlled trial comparing extended versus limited duration anticoagulation following a first unprovoked VTE (proximal deep vein thrombosis or pulmonary embolism). Adults were eligible if they had completed ≥3 months anticoagulation (remaining anticoagulated). The primary outcome was time to first recurrent VTE from randomisation. The secondary outcomes included PTS severity, bleeding, QoL and D-dimers. Two-hundred and eighty-one patients were recruited, randomised and followed up for 24 months (mean age 63, male:female 2:1). There was a significant reduction in recurrent VTE for patients receiving extended anticoagulation [2·75 vs. 13·54 events/100 patient years, adjusted hazard ratio (aHR) 0·20 (95% confidence interval (CI): 0·09 to 0·46, P < 0·001)] with a non-significant increase in major bleeding [3·54 vs. 1·18 events/100 patient years, aHR 2·99 (95% CI: 0·81-11·05, P = 0·10)]. Outcomes of PTS and QoL were no different between groups. D-dimer results (on anticoagulation) did not predict VTE recurrence. In conclusion, extended anticoagulation reduced VTE recurrence but did not reduce PTS or improve QoL and was associated with a non-significant increase in bleeding. Results also suggest very limited clinical utility of D-dimer testing on anticoagulated patients.

Extending venous thromboembolism secondary prevention with apixaban in cancer patients: The EVE trial

BACKGROUND

Cancer-associated venous thromboembolism (VTE) carries a high rate of recurrence and death. Guidelines recommend continued anticoagulation therapy as long as active cancer persists. Apixaban 2.5 mg twice daily is the FDA-approved dose for secondary prevention regardless of VTE causation. Whether this apixaban dose is appropriate for secondary VTE prevention in cancer patients is not clear. The rationale and design of this investigator initiated phase III, multicenter, randomized, double-blind, trial assessing apixaban 2.5 mg vs 5 mg twice daily for 12 months for the secondary VTE prevention in cancer patients (n = 370) who have completed 6 months (but no more than 12 months) of anticoagulation is provided (NCT03080883).

METHODS/DESIGN

The primary study objective is to estimate differences in the combined rate of major plus clinically relevant non-major bleeding for apixaban 2.5 mg vs 5 mg twice daily. Secondary efficacy outcome is to assess rates of venous or arterial thromboembolism. Participating centers are chosen from the Academic and Community Cancer Research United (ACCRU) consortium.

CONCLUSION

We anticipate these trial results to provide evidence supporting low-dose apixaban as a safe agent for secondary prevention of cancer-associated VTE for patients who have already completed 6-12 months of anticoagulation.

Monitoring of low dabigatran concentrations: diagnostic performance at clinically relevant decision thresholds

The direct oral anticoagulant dabigatran does not require therapeutic drug monitoring, however emergency measurements are gaining importance. Current assays feature good performance at intermediate and high dabigatran concentrations but show limited accuracy at low concentrations. This area requires more attention as clinical decision threshold values currently lie at 30 and 50 ng/ml. The objective of the study was to evaluate and compare diagnostic performance of dabigatran assays at these thresholds. Dabigatran concentrations of 293 plasma samples taken from 50 patients were measured with the INNOVANCE direct thrombin inhibitor assay (DTI) from Siemens, the Biophen direct thrombin inhibitor assay (BDTI), the BDTI using a low range calibrator (BDTI-low), the Hemoclot direct thrombin inhibitor assay (HTI) and an ecarin clotting time assay (ECT). Assay results were compared to ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), and test characteristics were calculated for thresholds of 30 and 50 ng/ml. DTI, BDTI-low and ECT showed very strong correlation and high agreement with UPLC-MS/MS and an improved determination of low dabigatran concentrations. ROC curve analyses revealed very high accuracy at the 30/50 ng/ml thresholds for DTI (AUC = 0.989/0.995), BDTI-low (AUC = 0.980/0.991) and ECT (AUC = 0.990/0.996) measurements. Sensitivity and specificity in detecting were calculated for DTI (98/92%), BDTI-low (87/95%), ECT (97/96%), BDTI (99/82%) and HTI (86/89%) measurements. Compared to the previously available HTI and BDTI, both novel assays, DTI and BDTI-low, reliably determine low dabigatran plasma concentrations around the clinical decision thresholds with very high sensitivity and specificity.

Cost-effectiveness of rivaroxaban versus apixaban for the initial treatment of venous thromboembolism and extended prevention of recurrences in the UK

Aim: To evaluate the relative cost-effectiveness of using rivaroxaban vs apixaban for the initial treatment plus extended prevention of venous thromboembolism (VTE) in the UK. Extended prevention was assessed using a 10-mg rivaroxaban dose, as the 20-mg dose has already been evaluated. Methods: A Markov model compared the health outcomes and costs of treating VTE patient cohorts with either rivaroxaban (15 mg twice daily for 3 weeks, followed by 20 mg once daily for 6 months, then extended prevention with 10 mg once daily) or apixaban (10 mg twice daily for 1 week, followed by 5 mg twice daily for 6 months, then extended prevention with 2.5 mg twice daily) over a lifetime horizon. The model included an initial acute treatment and prevention phase (0-6 months) and an extended prevention phase (6-18 months). Efficacy and safety data were derived from two network meta-analyses. Reference treatment comparators were derived from the EINSTEIN-Pooled study and EINSTEIN-CHOICE trial. Healthcare costs and utility data were derived from published literature. Results: The rivaroxaban regimen was associated with increased quality-adjusted life years (QALYs) and slightly lower total costs compared with apixaban over a lifetime horizon. Deterministic and probabilistic sensitivity analyses demonstrated that rivaroxaban remained a cost-effective alternative to apixaban over a wide range of parameters. Incremental cost-effectiveness ratio estimates were below the £20,000 per QALY threshold in 74.1% of 2,000 model simulations. Scenario analyses further supported that rivaroxaban is a cost-effective alternative to apixaban. Limitations: Clinical and safety inputs were derived from network meta-analysis, which are subject to inherent limitations whereby small differences between study designs may severely impact efficacy and safety outcomes. Furthermore, these inputs were based on data from clinical trials, which may not reflect real-world data. Conclusions: Rivaroxaban was associated with a slightly lower total cost and increased QALYs compared with apixaban for VTE management in the UK over a lifetime horizon.

Evaluation of the safety and effectiveness of direct oral anticoagulants and low molecular weight heparin in gastrointestinal cancer-associated venous thromboembolism

BACKGROUND

Gastrointestinal cancer (GICA) is associated with a higher incidence of venous thromboembolism (VTE) compared to other solid tumors, moreover, recurrent VTE and major bleeding (MB) complications during anticoagulation treatment have an associated increase rate. GICA-VTE remains a challenging clinical scenario with MB concerns for utilization of direct oral anticoagulants (DOAC), especially with active cancer therapies.

AIM

To evaluate patient risk factors, effectiveness (VTE) and safety (MB) of DOACs and low molecular weight heparin (LMWH) in patients with active GICA-VTE.

METHODS

A retrospective chart review of patients receiving DOACs and LMWH with GICA and symptomatic or incidental VTE treated at comprehensive cancer center from November 2013 to February 2017 was performed. Inclusion criteria included active GI cancer diagnosed at any stage or treatment +/- 6 mo of VTE diagnosis, whom were prescribed 6 mo or more of DOACs or LMWH. The Chi-squared test was used for overall and the Fisher exact test for pairwise comparisons of the proportions of patients experiencing recurrent VTE and MB events. Odds ratios were used to compare the relative odds of the occurrence of the outcome given exposure to the risk factor.

RESULTS

A total of 144 patients were prescribed anticoagulation, in which 106 fulfilled inclusion criteria apixaban (27.3%), rivaroxaban (34.9%) and enoxaparin (37.7%), and 38 were excluded. Patients median age was 66.5 years at GICA diagnosis and 67 years at CAVTE event, with 62% males, 80% Caucasian, 70% stage IV, pancreatic cancer (40.5%), 30% Khorana Score (≥ 3 points), and 43.5% on active chemotherapy. Sixty-four percent of patients completed anticoagulation therapy (range 1 to 43 mo). Recurrent VTE at 6 mo was noted in 7.5% (n = 3), 6.8% (n = 2) and 2.7% (n = 1) of patients on enoxaparin, apixaban and rivaroxaban, respectively (all P = NS). MB at 6 mo were 5% (n = 2) for enoxaparin, 6.8% (n = 2) for apixaban and 21.6% (n = 8) for rivaroxaban (overall P = 0.048; vs LMWH P = 0.0423; all other P = NS). Significant predictors of a primary or secondary outcome for all anticoagulation therapies included: Active systemic treatment (OR = 5.1, 95%CI: 1.3-19.3), high Khorana Score [≥ 3 points] (OR = 5.5, 95%CI: 1.7-17.1), active smoker (OR = 6.7, 95%CI: 2.1-21.0), pancreatic cancer (OR = 6.8, 95%CI: 1.9-23.2), and stage IV disease (OR = 9.9, 95%CI: 1.2-79.1).

CONCLUSION

Rivaroxaban compared to apixaban and enoxaparin had a significantly higher risk of MB on GICA-VTE patients with equivocal efficacy.

Non-Vitamin K Antagonist Oral Anticoagulants in Medical Conditions at High Risk of Thromboembolism beyond Atrial Fibrillation

Non-Vitamin K antagonist oral anticoagulants (NOACs) have been extensively investigated in medical conditions at high risk of venous or arterial thrombosis other than atrial fibrillation (AF), including hip or knee arthroplasty, acute venous thromboembolism (VTE), cancer-associated VTE, acute coronary syndrome (ACS), stable atherosclerotic vascular disease, chronic heart failure, and embolic stroke of undetermined source (ESUS). Two large ESUS trials failed to show the benefit of rivaroxaban or dabigatran, and large randomized controlled trial (RCT) data of NOACs are lacking for another potential candidates of patent foramen ovale-related stroke, acute ischemic stroke, and cerebral venous thrombosis. On the other hand, high quality evidences of NOACs have been compiled for VTE prophylaxis after hip or knee arthroplasty, acute VTE, cancer-associated VTE, and concomitant ACS and AF, which have been reflected in clinical practice guidelines. In addition, RCTs showed the benefit of very low dose rivaroxaban in combination with antiplatelet therapy in patients with ACS and in those with stable cardiovascular disease. This article summarizes the accumulated evidences of NOACs in cardiovascular diseases beyond AF, and aims to inform healthcare providers of optimal regimens tailored to individual medical conditions and help investigators design future clinical trials.

Using non-vitamin K oral anticoagulants in specific patient populations: a study of Korean cases

Non-vitamin K oral anticoagulants (NOACs) are increasingly used as alternatives to conventional therapies and have considerable accumulated real-world clinical data in patients with non-valvular atrial fibrillation (NVAF) or venous thromboembolism (VTE). However, it is not easy to make a complete changeover to NOACs in real-world clinical practice because NOACs still have challenges in specific patient populations (eg, Asian patients, NVAF patients presenting with acute coronary syndrome [ACS], dialysis patients with NVAF, patients with cancer-associated VTE, etc.). Clinical data on the optimal dose of NOACs in Asian patients with NVAF are not sufficient. The intensity of NOAC and antiplatelet treatment and the duration of antiplatelet treatment should be adjusted according to the bleeding and thrombotic risk profiles of the individual NVAF patient presenting with ACS. Increased bleeding risk and unclear efficacy of NOACs in dialysis patients with NVAF should be considered when making decisions on whether to give NOACs for these patients. If dialysis patients with NVAF require anticoagulant for stroke prevention, then apixaban could be considered while awaiting more clinical efficacy and safety data. Additional studies are needed to determine the utility of continuing treatment with reduced-dose NOACs for long-term therapy after VTE. We have enough experiences in using NOACs in cancer patients showing the benefit of antithrombotic treatment counterbalanced the bleeding risk; however, some challenges of cancer-associated VTE management exist due to differences in cancer types or chemotherapy regimens and comorbidities. Different dosing regimens among NOACs may impact on medication adherence; thus, individual patient preference should be considered in choosing a particular NOAC. A significant proportion of patients remain on warfarin because of the high price of NOACs and variability in reimbursement coverage. To compensate clinical-evidence and achieve optimal use of NOACs, we should pay attention to the outcomes of ongoing studies and evaluate more real-world data.

Direct Oral Anticoagulants: Novel Approach for the Treatment of Thrombosis in Pediatric Patients?

Venous thromboembolism (VTE) is a rare, but life-threatening disease in those who have not reached their adulthood. This condition is usually treated with heparin or low molecular weight heparins which require parenteral administration and, in case of unfractionated heparin, also frequent laboratory monitoring and dose adjustment. Direct oral anticoagulants (DOACs)-direct thrombin inhibitor dabigatran, and direct oral factor Xa inhibitors rivaroxaban, apixaban, and edoxaban-are currently frequently used for the prevention and treatment of VTE in adult population. In fact, these agents offer several advantages compared to traditional agents, such as oral route of administration, short on-set and off-set of action, predictable pharmacologic profile with low risk of food and drug interactions, and no need for routine laboratory assessment of anticoagulant activity. However, clinical experience with these directly acting oral anticoagulants in pediatric population is very limited as these drugs had been tested and are used mostly in adult individuals. This article reviews the current data from pre- and post-marketing studies reporting the use of DOACs for the treatment of VTE in pediatric patients.

Differences In Gastrointestinal Safety Profiles Among Novel Oral Anticoagulants: Evidence From A Network Meta-Analysis

Background

There is no consensus at present regarding the differences in the risk of GI bleeding across various NOAC regimens. Therefore, we performed a network meta-analysis to compare the risk of gastrointestinal bleeding after different NOAC regimens.

Methods

PubMed, Cochrane, Web of Science, Clinicaltrial.gov and Clinicaltrialresults.org were searched for randomized controlled trials (RCTs) assessing gastrointestinal bleeding of all NOAC regimens from inception to January 2018. The primary endpoint was major gastrointestinal (MGI) bleeding. The meta-regression was performed to access the association between the MGI bleeding events and mortality. The network meta-analysis was carried out with the Bayesian random-effect model.

Results

A total of 25 RCTs, including 139,392 patients, were identified. Meta-regression analysis showed that MGI bleeding was correlated with fatal bleeding events (odds ratios [OR], 1.76; 95% confidence interval [CI], 1.13-2.77], P=0.015). The network meta-analysis results showed that compared to the conventional regimens, rivaroxaban was associated with increased risk of MGI bleeding (OR, 1.37; 95% credible interval [CrI], 1.00-1.85), but not the apixaban (OR, 0.77; 95% CrI, 0.53-1.07]), edoxaban (OR, 0.86; 95%CrI, 0.52-1.18) and dabigatran etexilate (OR, 1.22; 95% CrI, 0.82-1.69). Compared to rivaroxaban, apixaban (OR, 0.56; 95% CrI, 0.35-0.88) and edoxaban (OR, 0.62; 95% CrI, 0.35-0.96) showed a significantly lower risk of MGI bleeding. Apixaban had the highest probability of being the safest option with regard to the risk of MGI bleeding (89.1%), followed by edoxaban (77.4%), conventional therapy (51.4%), dabigatran etexilate (23.8%) and rivaroxaban (8.3%).

Conclusion

The risk of GI bleeding significantly varies among different NOAC regimens, and evidence shows that apixaban and edoxaban had the most favorable MGI bleeding safety profile, while rivaroxaban and dabigatran etexilate were the least safe.

Direct Anticoagulants and Risk of Myocardial Infarction, a Multiple Treatment Network Meta-Analysis

We assessed the cardiovascular safety of long-term direct-acting oral anticoagulant (DOAC) treatment. A search of the medical literature was performed from inception until May 31, 2019. Inclusion criteria were (1) randomized trial that assessed the clinical efficacy and/or safety of 1 or more DOAC, (2) control group including oral anticoagulation and/or antiplatelet and/or placebo treatment, and (3) the incidence of acute coronary syndrome during follow-up was reported. Fixed-effect and random-effects models were applied. The analyzed outcomes were myocardial infarction (MI), major bleeding, and mortality. Twenty-eight randomized clinical trials (196 761 patients) were included. Rivaroxaban was associated with a 21% reduction in the relative risk of MI when compared to placebo (relative risk [RR]: 0.79 [95% credible interval, CrI: 0.65-0.94]) and a 31% reduction (RR: 0.70 [95% CrI: 0.53-0.89]) when compared to dabigatran. Apixaban resulted in 24% (RR: 0.76 [95% CrI: 0.58-0.99]) and vitamin K antagonists anticoagulation resulted in 19% (RR: 0.81 [95% CrI: 0.65-0.98]) risk reduction compared to dabigatran. The computed probability of being the first best choice of treatment was 61.8% for rivaroxaban. Cardiovascular safety shows considerable heterogeneity among oral anticoagulants. Treatment with rivaroxaban is associated with reduced rate of MI.

Who should get long-term anticoagulant therapy for venous thromboembolism and with what?

After an initial 3 to 6 months of anticoagulation for venous thromboembolism (VTE), clinicians and patients face an important question: "Do we stop anticoagulants or continue them indefinitely?" The decision is easy in some scenarios (eg, stop in VTE provoked by major surgery). In most scenarios, which are faced on a day-to-day basis in routine practice, it is a challenging decision because of uncertainty in estimates in the long-term risks (principally major bleeding) and benefits (reducing recurrent VTE) and the tight trade-offs between them. Once the decision is made to continue, the next question to tackle is "Which anticoagulant?" Here again, it is a difficult decision because of the uncertainty with regard to estimates of efficacy and the safety of anticoagulant options and the tight trade-offs between choices. We conclude with the approach that we take in our clinical practice.

Sex matters: Practice 5P's when treating young women with venous thromboembolism

Sex matters when it comes to venous thromboembolism (VTE). We defined 5P's - period, pill, prognosis, pregnancy, and postthrombotic syndrome - that should be discussed with young women with VTE. Menstrual blood loss (Period) can be aggravated by anticoagulant therapy. This seems particularly true for direct oral anticoagulants. Abnormal uterine bleeding can be managed by hormonal therapy, tranexamic acid, or modification of treatment. The use of combined oral contraceptives (Pill) is a risk factor for VTE. The magnitude of the risk depends on progestagen types and estrogen doses used. In women using therapeutic anticoagulation, concomitant hormonal therapy does not increase the risk of recurrent VTE. Levonorgestrel-releasing intrauterine devices and low-dose progestin-only pills do not increase the risk of VTE. In young women VTE is often provoked by transient hormonal risk factors that affects prognosis. Sex is incorporated as predictor in recurrent VTE risk assessment models. However, current guidelines do not propose using these to guide treatment duration. Pregnancy increases the risk of VTE by 4-fold to 5-fold. Thrombophilia and obstetric risk factors further increase the risk of pregnancy-related VTE. In women with a history of VTE, the risk of recurrence during pregnancy or post partum appears to be influenced by risk factors present during the first VTE. In most women with a history of VTE, antepartum and postpartum thromboprophylaxis with low-molecular-weight heparin is indicated. Women generally are affected by VTE at a younger age then men, and they have to deal with long-term complications (Post-thrombotic syndrome) of deep vein thrombosis early in life.