New oral anticoagulants versus vitamin K antagonists before cardioversion of atrial fibrillation: a meta-analysis of data from 4 randomized trials

Background: Scarce data are available about efficacy and safety of new oral anticoagulants (NOACs) for cardioversion (CV) of atrial fibrillation (AF). We performed a meta-analysis of data from randomized studies reporting outcomes of patients receiving NOACs, as compared to vitamin K antagonists (VKAs), and undergoing CV of AF. Methods: Data from four studies were selected, including 4268 CVs. The primary endpoints were the incidence of stroke or systemic embolism and the incidence of major bleeding within 30 days. Results: There was not any significant difference in the incidence of stroke or systemic embolism between NOACs and VKAs (RR 0.73, p = 0.47) nor in the incidence of major bleeding (RR 1.39, p = 0.13). Conclusions: We found no evidence of differential outcomes after CV of AF according to treatment with NOACs or VKAs. This finding warrants confirmation in larger clinical series and in the setting of properly powered randomized trials of newly diagnosed AF.     

Pharmacological and Non-pharmacological Treatments for Stroke Prevention in Patients with Atrial Fibrillation

Atrial fibrillation (AF) is associated with significant risk of stroke and other thromboembolic events, which can be effectively prevented using oral anticoagulation (OAC) with either vitamin K antagonists (VKAs) or non-VKA oral anticoagulants (NOACs) dabigatran, rivaroxaban, apixaban, or edoxaban. Until recently, VKAs were the only available means for OAC treatment. NOACs had similar efficacy and were safer than or as safe as warfarin with respect to reduced rates of hemorrhagic stroke or other intracranial bleeding in the respective pivotal randomized clinical trials (RCTs) of stroke prevention in non-valvular AF patients. Increasing “real-world” evidence on NOACs broadly confirms the results of the RCTs. However, individual patient characteristics including renal function, age, or prior bleeding should be taken into account when choosing the OAC with best risk–benefit profile. In patients ineligible for OACs, surgical or interventional stroke prevention strategies should be considered. In patients undergoing cardiac surgery for other reasons, the left atrial appendage excision, ligation, or amputation may be the best option. Importantly, residual stumps or insufficient ligation may result in even higher stroke risk than without intervention. Percutaneous left atrial appendage occlusion, although requiring minimally invasive access, failed to demonstrate reduced ischemic stroke events compared to warfarin. In this review article, we summarize current treatment options and discuss the strengths and major limitations of the therapies for stroke risk reduction in patients with AF.     

Non-vitamin K antagonist oral anticoagulants in atrial fibrillation patients with bioprosthetic valves

Introduction: The non-vitamin K antagonist oral anticoagulants (NOACs), which include dabigatran, apixaban, edoxaban and rivaroxaban, are preferred over vitamin K antagonists for stoke prevention in most patients with non-valvular atrial fibrillation. The NOACs are contraindicated in atrial fibrillation patients with rheumatic mitral stenosis or mechanical heart valves. There is evidence that bioprosthetic heart valves are less thrombogenic than mechanical heart valves, but it is unknown whether the risk of thromboembolism in atrial fibrillation patients with bioprosthetic valves differs from that in patients without such valves.

Areas covered: The authors present a review of the efficacy and safety evidence surrounding the use of NOACs for stroke prevention in atrial fibrillation patients with bioprosthetic heart valves.

Expert commentary: While the data is limited, there is no significant difference in thromboembolic, and bleeding outcomes in patients with AF and bioprosthetic heart valves treated with NOAC therapy. Future studies are required before definitive conclusions can be drawn regarding the safety and efficacy of NOAC therapy in AF patients bioprosthetic heart valves.     

Personalizing oral anticoagulant treatment in patients with atrial fibrillation

For decades, warfarin has remained the standard oral anticoagulation for stroke prevention in atrial fibrillation (AF). Three novel oral anticoagulants (NOACs) have been recently approved for stroke prevention in non-valvular AF: dabigatran, rivaroxaban and apixaban. Better pharmacological and clinical profiles make these newcomers a preferable alternative over warfarin. Current AF guidelines do not endorse NOACs over warfarin, or one NOAC over another. Indeed, choice of the anticoagulation regimen should be personalized based on the relative efficacy and safety of different agents across subgroups stratified by thrombotic and bleeding risk, as well as on other clinical factors, including anticoagulation control on warfarin, drug interactions, compliance and need for coagulation monitoring. This review appraises i) the randomized evidence on approved NOACs versus warfarin in AF across subgroups stratified by risk factors of stroke and bleeding and by the anticoagulation level reached on warfarin; and ii) clinical factors impacting on the anticoagulation regimen selection.     

Non-Vitamin K Oral Anticoagulants for Stroke Prevention in Special Populations with Atrial Fibrillation

Atrial fibrillation (AF) is associated with an increased risk of ischemic stroke or systemic embolism compared with normal sinus rhythm. These strokes may efficiently be prevented in patients with risk factors using oral anticoagulant therapy, with either vitamin K antagonists (VKAs) or non-vitamin K antagonist oral anticoagulants (NOACs) (i.e., direct thrombin inhibitors or direct factor Xa inhibitors). Owing to their specific risk profiles, some AF populations may have increased risks of both thromboembolic and bleeding events. These AF patients may be denied oral anticoagulants, whilst evidence shows that the absolute benefits of oral anticoagulants are greatest in patients at highest risk. NOACs are an alternative to VKAs to prevent stroke in patients with “non-valvular AF”, and NOACs may offer a greater net clinical benefit compared with VKAs, particularly in these high-risk patients. Physicians have to learn how to use these drugs optimally in specific settings. We review concrete clinical scenarios for which practical answers are currently proposed for use of NOACs based on available evidence for patients with kidney disease, elderly patients, women, patients with diabetes, patients with low or high body weight, and those with valve disease.     

Decision-Making in Clinical Practice: Oral Anticoagulant Therapy in Patients with Non-valvular Atrial Fibrillation and a Single Additional Stroke Risk Factor

Approximately 1 in 3–4 patients presenting with an ischemic stroke will also have atrial fibrillation (AF), and AF-related strokes can be effectively prevented using oral anticoagulant therapy (OAC), either with well-controlled vitamin K antagonists (VKAs) or non-vitamin K antagonist oral anticoagulants (NOACs). In addition, OAC use (both VKAs and NOACs) is associated with a 26% reduction in all-cause mortality (VKAs) or an additional 10% mortality reduction with NOACs relative to VKAs. The decision to use OAC in individual AF patient is based on the estimated balance of the benefit from ischemic stroke reduction against the risk of major OAC-related bleeding [essentially intracranial hemorrhage (ICH)]. Better appreciation of the importance of VKAs’ anticoagulation quality [a target time in therapeutic range (TTR) of ≥70%] and the availability of NOACs (which offer better safety compared to VKAs) have decreased the estimated threshold for OAC treatment in AF patients towards lower stroke risk levels. Still, contemporary registry-based data show that OAC is often underused in AF patients at increased risk of stroke. The uncertainty whether to use OAC may be particularly pronounced in AF patients with a single additional stroke risk factor, who are often (mis)perceived as having a “borderline” or insufficient stroke risk to trigger the use of OAC. However, observational data from real-world AF cohorts show that the annual stroke rates in such patients are higher than in patients with no additional stroke risk factors, and OAC use has been associated with reduction in stroke, systemic embolism, or death in comparison to no therapy or aspirin, with no increase in the risk of bleeding relative to aspirin. In this review article, we summarize the basic principles of stroke risk stratification in AF patients and discuss contemporary real-world evidence on OAC use and outcomes of OAC treatment in AF patients with a single additional stroke risk factor in various real-world AF cohorts.     

New oral anticoagulants: An emergency department overview

As of September 2013, three new oral anticoagulants (NOACs) are now available for clinical use on the Pharmaceutical Benefits Scheme in Australia. All three are for stroke prevention in atrial fibrillation, and one will also be available for the treatment of deep venous thrombosis and pulmonary embolism. All have been evaluated in large, multicentre randomised clinical trials. These drugs show at least equivalent efficacy to the current standard of care, the vitamin K antagonist warfarin. Major bleeding rates are overall comparable with warfarin, but there is an important reduction in intracranial bleeding of approximately 50% with all NOAC agents. The NOACs are administered in a simple, fixed dose regimen. There are a few clinically important interactions with other medications or diet. Concerns exist about the potential for irreversible bleeding in the small number of patients in which that occurs. This short report will discuss the pharmacology of these agents, the indications for use, aspects of laboratory monitoring and the management of bleeding with these agents.     

Adherence to oral anticoagulation in ischemic stroke patients with atrial fibrillation

BackgroundNon-vitamin K antagonist oral anticoagulants (NOAC) have superior safety and comparable efficacy profile compared to vitamin-K antagonists (VKAs), with more convenient dosing schemes. However, issues with adherence to the NOACs remain unsolved.AimsWe sought to investigate the adherence to oral anticoagulation (OAC) and baseline factors associated with poor adherence after ischaemic stroke in patients with atrial fibrillation (AF).MethodsWe recruited hospitalised patients (2013–2019) from two prospective stroke registries in Larissa and Helsinki University Hospitals and invited survived patients to participate in a telephone interview. We assessed adherence with the Adherence to Refills and Medications Scale (ARMS) and defined poor adherence as a score of over 17. In addition to demographics, individual comorbidities, and stroke features, we assessed the association of CHA₂DS₂-VASc and SAMe-TT₂R₂ scores with poor adherence.ResultsAmong 396 patients (median age 75.0 years, interquartile range [IQR] 70–80; 57% men; median time from ischaemic stroke to interview 21 months [IQR 12–33]; median ARMS score 17 [IQR 17–19]), 56% of warfarin users and 44% of NOAC users reported poor adherence. In the multivariable regression model adjusted for site, sex, and age, poor adherence was independently associated with tertiary education, absence of heart failure, smoking history, use of VKA prior to index stroke, and prior ischaemic stroke. CHA₂DS₂-VASc and SAMe-TT₂R₂ scores were not associated with poor adherence.ConclusionsAdherence was poor in half of AF patients who survived an ischaemic stroke. Independent patient-related factors, rather than composite scores, were associated with poor adherence in these patients.

KEY MESSAGES

• Adherence was poor in half of the atrial fibrillation patients who survived an ischaemic stroke.
• Independent patient-related factors rather than composite scores were associated with poor adherence.
• The findings support the importance of recognising adherence support as a crucial part of holistic patient care recommended by recent AF guideline.

     

Fitting the right non-vitamin K antagonist oral anticoagulant to the right patient with non-valvular atrial fibrillation: an evidence-based choice

Atrial fibrillation (AF) is the most prevalent arrhythmia and is associated with an increased risk of ischemic stroke (IS) and systemic embolism (SE). Stroke prevention is a key element for the overall management of AF patients. The non-vitamin K antagonist oral anticoagulants (NOACs), such as dabigatran, rivaroxaban, apixaban and edoxaban, are at least as effective as warfarin in reducing IS/SE with a lower rate of major bleeding. Various analyses from the large Phase III randomized trials demonstrated different efficacy and safety of NOACs in specific subgroups of patients. The randomized trials are supplemented by effectiveness and safety data from real-world observational cohorts following the availability of these drugs for use in everyday clinical practice. Given the clinical heterogeneity of AF patients, the available data from trials and real-world studies allow us to fit the right NOAC to the particular patient’s characteristics, with the aim of optimizing outcomes for the individual patient. This review article aims to provide a summary of the evidence on the performance of NOACs in AF patients with specific clinical characteristics. Evidence-based suggestions are presented to provide a simple and viable strategy for clinicians for the choice of a particular NOAC.

• KEY MESSAGE

• Given the different performance of the new-oral anticoagulants in patients with the different clinical situation, evidence-based choice of fitting the right new-oral anticoagulants to the patients is provided in this review article.

     

Phase III studies on novel oral anticoagulants for stroke prevention in atrial fibrillation: a look beyond the excellent results

Summary. In this overview we address the three phase III studies that compared new oral anticoagulants (dabigatran, rivaroxaban and apixaban) with warfarin in the setting of stroke prevention in atrial fibrillation. Strengths and weaknesses of the studies were examined in detail through indirect comparison. We analyze and comment the inclusion and exclusion criteria, the characteristics of randomized patients, the primary efficacy and safety end points and side effects. All new oral anticoagulants resulted in being non‐inferior to vitamin K antagonists in reducing stroke or systemic embolism in patients with atrial fibrillation. Dabigatran 150 mg and apixaban were superior to vitamin K antagonists. Importantly, new oral anticoagulants significantly reduced hemorrhagic stroke in all three studies. Major differences among new oral anticoagulants include the way they are eliminated and side effects. Both dabigatran and apixaban were tested in low‐ to moderate‐risk patients (mean CHADS2 [Congestive heart failure, Hypertension, Age, Diabetes, Stroke] score = 2.1–2.2) whereas rivaroxaban was tested in high‐risk patients (mean CHADS2 score = 3.48) and at variance with dabigatran and apixaban was administered once daily. Apixaban significantly reduced mortality from any cause. The choice of a new oral anticoagulant should take into account these and other differences between the new drugs.     

Approach to the new oral anticoagulants in family practice: Part 1: comparing the options

Objective

To compare key features of the new oral anticoagulants (NOACs)—dabigatran, rivaroxaban, and apixaban—and to address questions that arise when comparing the NOACs.

Sources of information

PubMed was searched for recent (January 2008 to week 32 of 2013) clinical studies relating to NOAC use for stroke prevention in atrial fibrillation (AF) and for the treatment of acute venous thromboembolism (VTE).

Main message

All NOACs are at least as effective as warfarin for stroke prevention in patients with nonvalvular AF, and are at least as safe in terms of bleeding risk according to 3 large trials. Meta-analyses of these trials have shown that, compared with warfarin therapy, NOACs reduced total mortality, cardiovascular mortality, and intracranial bleeding, and there was a trend toward less overall bleeding. Practical advantages of NOACs over warfarin include fixed once- or twice-daily oral dosing without the need for coagulation monitoring, and few known or defined drug or food interactions. Potential drawbacks of NOACs include a risk of bleeding that might be increased in patients older than 75 years, increased major gastrointestinal bleeding with high-dose dabigatran, increased dyspepsia with dabigatran, the lack of a routine laboratory test to reliably measure anticoagulant effect, and the lack of an antidote for reversal. No direct comparisons of NOACs have been made in randomized controlled trials, and the choice of NOAC is influenced by individual patient characteristics, including risk of stroke or VTE, risk of bleeding, and comorbidity (eg, renal dysfunction).

Conclusion

The NOACs represent important alternatives in the management of patients with AF and VTE, especially for patients who have difficulty accessing regular coagulation monitoring. The companion to this article addresses common “what if” questions that arise in the long-term clinical follow-up and management of patients receiving NOACs.     

A Review of the Efficacy and Safety Profiles of the Novel Oral Anticoagulants in the Treatment and Prevention of Venous Thromboembolism

Purpose

This study aims to review the published literature concerning the use of novel oral anticoagulants (NOACs) in the treatment and prevention of venous thromboembolism (VTE) and to identify the appropriate niche for each NOAC by comparing their behaviors in Phase III and Phase IV clinical trial settings.

非器质性心脏病心房颤动的治疗策略进展

心房颤动(房颤)是一种常见的心律失常。根据房颤的症状和时程可分为首发房颤、阵发性房颤、持续性房颤、长程持续性房颤和永久性房颤。根据血流动力性是否稳定和病程长短,可选择复律维持窦性心律策略、心室率控制策略和长期抗凝策略。新型口服抗凝剂可作为传统口服抗凝药物(OAC)的替代选择。除了药物治疗措施之外,房颤进行导管消融的地位逐渐提高,特别是对于非器质性心脏病的阵发性房颤患者,已经从过去的药物治疗失败后的可选治疗策略发展成为一线治疗策略。     

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

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

Novel Oral Anticoagulants for Stroke Prevention in Atrial Fibrillation: Focus on Apixaban

Stroke prevention in atrial fibrillation (AF) has been challenging over decades, mostly due to a number of difficulties associated with oral vitamin K antagonists (VKAs), which have been the most effective stroke prevention treatment for a long time. The oral direct thrombin inhibitors (e.g., dabigatran) and oral direct inhibitors of factor Xa (e.g., rivaroxaban, apixaban) have emerged recently as an alternative to VKAs for stroke prevention in AF. These drugs act rapidly, and have a predictable and stable dose-related anticoagulant effect with a few clinically relevant drug-drug interactions. The novel oral anticoagulants are used in fixed doses with no need for regular laboratory monitoring of anticoagulation intensity. However, each of these drugs has distinct pharmacological properties that could influence optimal use in clinical practice. The following phase 3 randomized trials with novel oral anticoagulants versus warfarin for stroke prevention in AF have been completed: the Randomized Evaluation of Long-term Anticoagulant therapy (RE-LY) trial with dabigatran, the Rivaroxaban Once daily oral direct Factor Xa inhibition Compared with vitamin K antagonism for prevention of stroke and Embolism Trial in Atrial Fibrillation (ROCKET-AF) trial with rivaroxaban, and the Apixaban for Reduction of Stroke and Other Thromboembolism Events in Atrial Fibrillation (ARISTOTLE) trial with apixaban. Moreover, the Apixaban Versus Acetylsalicylic Acid to prevent Strokes (AVERROES) trial included patients with AF who have failed or were unsuitable for warfarin, and compared apixaban versus aspirin for stroke prevention in AF. Overall, apixaban has two large trials for stroke prevention in AF showing benefits not only over warfarin, but also over aspirin among those patients who have failed or refused warfarin. In the ARISTOTLE trial, apixaban was superior to warfarin in the reduction of stroke or systemic embolism, major bleeding, intracranial hemorrhage, and all-cause mortality, with a similar reduction in the rate of ischemic stroke and better tolerability. When compared with aspirin in the AVERROES trial, apixaban was associated with more effective reduction of stroke, a similar risk of major bleeding, and better tolerability. In this review article, the authors summarize the current knowledge on novel oral anticoagulants and discuss the clinical aspects of their use for stroke prevention in AF, with particular emphasis on apixaban.     

The place of newer oral anticoagulants in the treatment of patients with non‐valvular atrial fibrillation and coronary artery disease

With the arrival of the newer oral anticoagulants (NOACs), we now have a more convenient means of providing anticoagulation for patients with non‐valvular atrial fibrillation (AF). Are there any particular considerations for the many patients who also have coronary artery disease? For many patients there is an obvious need to use the newer agents but for others, such as those who simply refuse to consider using a vitamin K antagonist (VKA) such as warfarin, the decision may be more problematical.     

Comparison of the Cost-effectiveness of New Oral Anticoagulants for the Prevention of Stroke and Systemic Embolism in Atrial Fibrillation in a UK Setting

PurposeThree new oral anticoagulants (NOACs) have recently become available in the United Kingdom as an alternative to warfarin in the prevention of stroke and systemic embolism in atrial fibrillation. This study examines the relative cost-effectiveness of dabigatran (BID dosing of 150 mg or 110 mg based on patient age), rivaroxaban, and apixaban from a UK payer perspective.MethodsA previously published model that follows up patients through treatment of atrial fibrillation during a lifetime was adapted to allow comparison of the 3 NOACs and warfarin. Acute thromboembolic and bleeding events, as well as long-term consequences of stroke, intracranial hemorrhage, and acute myocardial infarction, were tracked. Relative efficacy was calculated from a formal indirect treatment comparison using data from the 3 key trials (Randomized Evaluation of Long-Term Anticoagulation Therapy, Rivaroxaban Once-daily oral direct factor Xa inhibition Compared with vitamin K antagonism for prevention of stroke and Embolism Trial in Atrial Fibrillation, and Apixaban for the Prevention of Stroke in Subjects With Atrial Fibrillation) of the NOACs. Data from the rivaroxaban trial were adjusted for the difference in international normalized ratio control among warfarin patients versus the other 2 trials. Model outputs included total costs, event rates, and quality-adjusted life-years.FindingsAmong the patients taking NOACs, those taking dabigatran had the highest total QALYs (7.68 QALYs), followed by apixaban (7.63 QALYs) and rivaroxaban (7.47 QALYs). Patients taking dabigatran had the lowest total lifetime costs (£23,342), followed by apixaban (£24,014) and rivaroxaban (£25,220). The differences between dabigatran and apixaban were modest but consistent in sensitivity analyses, with the directionality only changing at the limits of the CIs for the relative risks of ischemic stroke or intracranial hemorrhage or when assuming that both treatment discontinuation and post-event disability rates differ by drug.ImplicationsDabigatran was found to be economically dominant over rivaroxaban and apixaban in the UK setting. These economic findings are based on relative clinical efficacy from an indirect treatment comparison and would benefit from any data of direct comparisons of the NOACs in the future.     

Periprocedural management of patients receiving a vitamin K antagonist or a direct oral anticoagulant requiring an elective procedure or surgery

The periprocedural management of patients receiving chronic therapy with oral anticoagulants (OACs), including vitamin K antagonists (VKAs) such as warfarin and direct OACs (DOACs), is a common clinical problem. The optimal perioperative management of patients receiving chronic OAC therapy is anchored on four key principles: (i) risk stratification of patient‐related and procedure‐related risks of thrombosis and bleeding; (ii) the clinical consequences of a thrombotic or bleeding event; (iii) discontinuation and reinitiation of OAC therapy on the basis of the pharmacokinetic properties of each agent; and (iv) whether aggressive management such as the use of periprocedural heparin bridging has advantages for the prevention of postoperative thromboembolism at the cost of a possible increase in bleeding risk. Recent data from randomized trials in patients receiving VKAs undergoing pacemaker/defibrillator implantation or using heparin bridging therapy for elective procedures or surgeries can now inform best practice. There are also emerging data on periprocedural outcomes in the DOAC trials for patients with non‐valvular atrial fibrillation. This review summarizes the evidence for the periprocedural management of patients receiving chronic OAC therapy, focusing on recent randomized trials and large outcome studies, to address three key clinical scenarios: (i) can OAC therapy be safely continued for minor procedures or surgeries; (ii) if therapy with VKAs (especially warfarin) needs to be temporarily interrupted for an elective procedure/surgery, is heparin bridging necessary; and (iii) what is the optimal periprocedural management of the DOACs? In answering these questions, we aim to provide updated clinical guidance for the periprocedural management of patients receiving VKA or DOAC therapy, including the use of heparin bridging.