Potential net clinical benefit of population-wide implementation of apixaban and dabigatran among European patients with atrial fibrillation

Anticoagulation for Atrial Fibrillation: A Review of Current Literature and Views

Atrial fibrillation is a common supraventricular tachyarrhythmia with uncoordinated atrial activation and ineffective atrial contraction. This leads to an increased risk of atrial thrombi, most commonly in the left atrial appendage, and increased risks of embolic strokes and/or peripheral thromboembolism. It is associated with significant morbidity and mortality. To meet the concerns of thrombi and stroke, anticoagulation has been the mainstay for prevention and treatment thereof. Historically, anticoagulation involved the use of aspirin or vitamin K antagonists, mainly warfarin. Since early 2010s, direct oral anticoagulants (DOACs) including dabigatran, rivaroxaban, apixaban, and edoxaban have been introduced and approved for anticoagulation of atrial fibrillation. DOACs demonstrated a dramatic reduction in the rate of intracranial hemorrhage as compared to warfarin, and offer the advantages of absolution of monitoring therefore avoid the risk of hemorrhages in the context of narrow therapeutic window and under-treatment characteristic of warfarin, particularly in high-risk patients. One major concern and disadvantage for DOACs was lack of reversal agents, which have largely been ameliorated by the approval of Idarucizumab for dabigatran and Andexanet alfa for both apixaban and rivaroxaban, with Ciraparantag as a universal reversal agent for all DOACs undergoing Fast-Track Review from FDA. In this article, we will be providing a broad review of anticoagulation for atrial fibrillation with a focus on risk stratification schemes and anticoagulation agents (warfarin, aspirin, DOACs) including special clinical considerations.

The Euro Heart Survey and EURObservational Research Programme (EORP) in atrial fibrillation registries: contribution to epidemiology, clinical management and therapy of atrial fibrillation patients over the last 20 years

Management of atrial fibrillation (AF) may be challenging in clinical practice. Given the complexity of AF patients and the continuous advances in AF clinical management, there is a need for standardized programmes aimed at collecting so-called 'real-world clinical practice data' regarding the epidemiology, diagnostic/therapeutic/management practices and assessing adherence to guidelines. Over the past 20 years, the number of registries and surveys based on real-world AF patients has been dramatically increased. In Europe, based on the Euro Heart Survey (EHS) and the EURObservational Research Programme (EORP), a large series of studies based on these prospective, observational, large-scale multicentre registries on AF have been published. This narrative review gives an overview of these two projects on AF led by the European Society of Cardiology, focusing mainly on the contribution that these studies have provided to AF management and patient outcomes. Both the EHS and the EORP registries have collected a large amount of data regarding contemporary clinical practice, and despite some limitations, mainly related to their observational nature, these registries have contributed to our knowledge and clinical management of AF patients.

Practice Gap in Atrial Fibrillation Oral Anticoagulation Prescribing at Emergency Department Home Discharge

INTRODUCTION

Current U.S. cardiology guidelines recommend oral anticoagulation (OAC) to reduce stroke risk in selected patients with atrial fibrillation (AF), but no formal AF OAC recommendations exist to guide emergency medicine clinicians in the acute care setting. We sought to characterize emergency department (ED) OAC prescribing practices after an ED AF diagnosis.

METHODS

This retrospective study included index visits for OAC-naive patients ≥18 years old who were discharged home from the ED at an urban, academic, tertiary hospital with a primary diagnosis of AF from 2012-2014. Five hypothesis-blinded, chart reviewers abstracted data from patient problem lists and medical history in the electronic health record to assess stroke (CHA₂DS₂-VASc) and bleeding risk (HAS-BLED). The primary outcome was the provision of an OAC prescription at discharge in OAC-naive patients with high stroke risk. Descriptive statistics and multivariable logistic regression assessed associations between OAC prescription and patient characteristics.

RESULTS

We included 138 patient visits in our analysis, of whom 39.9% (n = 55) were low stroke risk (CHA₂DS₂-VASc = 0 in males and 1 in females), 15.9% (n = 22) were intermediate risk (CHA₂DS₂-VASc = 1 in males), and 44.2% (n = 61) were high risk (CHA₂DS₂-VASc ≥ 2). Of patients with high stroke risk and low-to-intermediate bleeding risk (n = 57), 80.7% were not prescribed an OAC at discharge. Cardiology consultation and female gender, but not stroke risk (CHA₂DS₂-VASc score), were predictors of an ED provider prescribing an OAC to an OAC-naive AF patient at ED discharge.

CONCLUSION

The majority of OAC-eligible patients were discharged home without an OAC prescription. In OAC-naive patients discharged home from the ED, cardiology consultation and female gender were associated with OAC prescription. Our findings suggest that access to expert opinion may improve provider comfort with OAC prescribing and highlight the need for improved guidelines specific to ED-management of AF.

The Risk of Myocardial Infarction in Patients with Atrial Fibrillation Taking a Direct Thrombin Inhibitor: Myths and Reality

The purpose of this review is to analyze the results of randomized clinical trials, meta-analyses of cohort and observational studies in real clinical practice on the influence of dabigatran etexilate on the risk of myocardial infarction in patients with atrial fibrillation. A pivotal RE-LY study on dabigatran use in patients with atrial fibrillation did not show statistically significant differences in the frequency of myocardial infarction between any of the doses of dabigatran and warfarin, and the risk of coronary events did not depend on the presence of coronary heart disease or myocardial infarction in the patient's history. Subsequently, a number of meta-analyses have reported an increased risk of myocardial infarction when dabigatran was administered to patients with atrial fibrillation. In general, these studies were characterized by conflicting data, which did not allow to draw any definite conclusions regarding the use of dabigatran in relation to the risk of myocardial infarction. Two FDA cohort observational studies were published in 2014 and 2017, and the former was significantly criticized by experts, and the results of the second study did not provide a definitive answer to the question about the importance of the effect of dabigatran on the development of myocardial infarction in patients with atrial fibrillation. Even more "confusing" the problem arose after the publication of meta-analyses of randomized trials, which showed that the risk of myocardial infarction was increased in patients treated with direct oral anticoagulants compared to patients treated with warfarin. This review provides high quality evidence for the efficacy of dabigatran in preventing myocardial infarction and other vascular complications in patients with atrial fibrillation.

New oral anticoagulants for stroke prevention in atrial fibrillation: impact of study design, double counting and unexpected findings on interpretation of study results and conclusions

Four recently introduced new oral anticoagulants (dabigatran, rivaroxaban, apixaban and edoxaban) have been shown to be at least as efficacious and safe as warfarin for stroke prevention in patients with atrial fibrillation in their respective trials. The first three have been approved, while edoxaban is awaiting regulatory approval. Several guidelines have endorsed the approved new oral anticoagulants over warfarin because of their favourable risk-benefit ratio, low propensity for food and drug interactions, and lack of requirement for routine coagulation monitoring. In this invited review, we summarise the results of the four studies and discuss widely held conclusions. We take a step further and discuss how differences in study design, analysis plan, and unexpected events affect the interpretation of the study results. Finally, we take our re-interpretation of study results and discuss how they might impact clinical practice and anticoagulant choice for patients.

Stroke prevention in atrial fibrillation: An Asian perspective

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia. In 2050, it is estimated that there will be 72 million AF patients in Asia, accounting for almost 2.9 million patients suffering from AF-associated stroke. Asian AF patients share similar risk factor profiles as non-Asians, except that more Asians have a history of previous stroke. Clinical challenges are evident in the field of stroke prevention in AF, amongst Asians. Existing stroke and bleeding risk scores have not been well-validated in Asians. Asians are prone to bleeding when treated with warfarin, and the optimal international normalised ratio (INR) for warfarin use is yet to be determined in Asians, though Asian physicians tend to keep it in a lower range (e.g. INR 1.6–2.6) for elderly patients despite limited evidence to justify this. In general, warfarin is ‘difficult’ to use in Asians due to higher risk of bleeding and higher stroke rate in Asians than in non-Asians, as shown in randomised controlled trials. Excess of bleeding was not found in Asians when novel oral anticoagulants (NOACs) were used. Besides, the superiority of NOACs to warfarin in reducing thromboembolism was maintained in Asians. Therefore NOACs are preferentially indicated in Asians in terms of both efficacy and safety. Also, some preliminary data suggest that Asian patients with AF might not be the same. Future prospective randomised trials are needed for the selection of NOACs according to different ethnic background.

Note: The review process for this manuscript was fully handled by Christian Weber, Editor in Chief.

Feasibility and cost-effectiveness of stroke prevention through community screening for atrial fibrillation using iPhone ECG in pharmacies

Atrial fibrillation (AF) causes a third of all strokes, but often goes undetected before stroke. Identification of unknown AF in the community and subsequent anti-thrombotic treatment could reduce stroke burden. We investigated community screening for unknown AF using an iPhone electrocardiogram (iECG) in pharmacies, and determined the cost-effectiveness of this strategy. Pharmacists performed pulse palpation and iECG recordings, with cardiologist iECG over-reading. General practitioner review/12-lead ECG was facilitated for suspected new AF. An automated AF algorithm was retrospectively applied to collected iECGs. Cost-effectiveness analysis incorporated costs of iECG screening, and treatment/outcome data from a United Kingdom cohort of 5,555 patients with incidentally detected asymptomatic AF. A total of 1,000 pharmacy customers aged ≥65 years (mean 76 ± 7 years; 44% male) were screened. Newly identified AF was found in 1.5% (95% CI, 0.8–2.5%); mean age 79 ± 6 years; all had CHA2DS2-VASc score ≥2. AF prevalence was 6.7% (67/1,000). The automated iECG algorithm showed 98.5% (CI, 92–100%) sensitivity for AF detection and 91.4% (CI, 89–93%) specificity. The incremental cost-effectiveness ratio of extending iECG screening into the community, based on 55% warfarin prescription adherence, would be $AUD5,988 (€3,142; $USD4,066) per Quality Adjusted Life Year gained and $AUD30,481 (€15,993; $USD20,695) for preventing one stroke. Sensitivity analysis indicated cost-effectiveness improved with increased treatment adherence. Screening with iECG in pharmacies with an automated algorithm is both feasible and cost-effective. The high and largely preventable stroke/thromboembolism risk of those with newly identified AF highlights the likely benefits of community AF screening. Guideline recommendation of community iECG AF screening should be considered.

Previous Presentation: This study was presented in part as an oral presentation at the Cardiac Society of Australia and New Zealand Conference; 9 August 2013; Sydney, Australia, abstract published in Heart Lung Circulation 2013;22:S223.

Trial registration: Australian New Zealand clinical trials registry: ACTRN12612000406808.

Predictive value of CHADS2 and CHA2DS2-VASc scores for acute myocardial infarction in patients with atrial fibrillation

The presence of acute myocardial infarction (AMI) confers a poor prognosis in atrial fibrillation (AF), associated with increased mortality dramatically. This study aimed to evaluate the predictive value of CHADS₂ and CHA₂DS₂-VASc scores for AMI in patients with AF. This retrospective study enrolled 5140 consecutive nonvalvular AF patients, 300 patients with AMI and 4840 patients without AMI. We identified the optimal cut-off values of the CHADS₂ and CHA₂DS₂-VASc scores each based on receiver operating characteristic curves to predict the risk of AMI. Both CHADS₂ score and CHA₂DS₂-VASc score were associated with an increased odds ratio of the prevalence of AMI in patients with AF, after adjustment for hyperlipidaemia, hyperuricemia, hyperthyroidism, hypothyroidism and obstructive sleep apnea. The present results showed that the area under the curve (AUC) for CHADS₂ score was 0.787 with a similar accuracy of the CHA₂DS₂-VASc score (AUC 0.750) in predicting “high-risk” AF patients who developed AMI. However, the predictive accuracy of the two clinical-based risk scores was fair. The CHA₂DS₂-VASc score has fair predictive value for identifying high-risk patients with AF and is not significantly superior to CHADS₂ in predicting patients who develop AMI.

Viewpoint: Stroke Prevention in Recent Guidelines for the Management of Patients with Atrial Fibrillation: An Appraisal

Formal guidelines play an important role in disseminating the best available evidence knowledge and are expected to provide simple and practical recommendations for the most optimal management of patients with various conditions. Such guidelines have important implications for many disease states, which thereby could be more professionally managed in everyday clinical practice by clinicians with divergent educational backgrounds, and also more easily implemented in wards or outpatient clinics, eliminating inequalities in health care management. In this brief Viewpoint we provide an appraisal on the recommendations pertinent to the prevention of atrial fibrillation-related stroke or systemic thromboembolism, as provided in recently published guidelines for the management of this arrhythmia.

Patients' experiences of atrial fibrillation and non-vitamin K antagonist oral anticoagulants (NOACs), and their educational needs: A qualitative study

PURPOSE

Qualitative research on atrial fibrillation (AF) patient's experiences and perceptions of taking the non-vitamin K antagonist oral anticoagulants (NOACs) for stroke prevention is limited. This study explores patients' experiences of dabigatran and their recommendations for development of educational materials.

PATIENTS AND METHODS

Semi-structured individual interviews with 8 warfarin-naive and 8 warfarin-experienced AF patients, using qualitative deductive thematic analysis.

RESULTS

The four main overarching themes included: understanding the diagnosis; reaching a treatment decision; challenges of living with OAC; and patient perceptions of treatment. Patients discussed their shock of diagnosis, and seeking information and support at that time. Narratives suggest patients preferred to be led by the doctor when making treatment decisions, and would often compare dabigatran to warfarin. Patients reported side-effects and challenges with both treatment options, and discussed their beliefs surrounding medications, including misconceptions. In addition to the original framework, two further themes were added: challenges of living with AF, and patient recommendations. Generally patients found AF symptoms distressing, which impacted their quality of life. Patient recommendations included the content and delivery of educational materials and development of tools to help with their understanding of AF and anticoagulation, as well as treatment adherence and anxiety surrounding symptoms and side effects.

CONCLUSION

Patient recommendations emphasised the need for interventions to relieve anxiety surrounding the diagnosis and possible treatment side effects. Tailored 'disease-specific' support is essential to ensure efficacious treatment. This qualitative study highlights the need for patient involvement in the development of educational materials and resources for patients commencing treatment with NOACs.

Efficacy and safety of the target-specific oral anticoagulants for stroke prevention in atrial fibrillation: the real-life evidence

The aim of our article is to provide a concise review for clinicians entailing the main studies that evaluated the efficacy and safety of target-specific oral anticoagulants (TSOAs) for thromboembolic stroke prevention in the real-world setting. Atrial fibrillation (AF) is one of the most common supraventricular arrhythmias that requires anticoagulation therapy to prevent stroke and systemic embolism. TSOAs, dabigatran, apixaban and rivaroxaban have become available as an alternative to warfarin anticoagulation in nonvalvular atrial fibrillation (NVAF). Randomized clinical trials showed non-inferior or superior results in efficacy and safety of the TSOAs compared with warfarin for stroke prevention in NVAF patients. For this reason, the 2012 update to the European Society of Cardiology guidelines for the management of AF recommends TSOAs as broadly preferable to vitamin K antagonists (VKAs) in the vast majority of patients with NVAF [Camm et al. 2012]. Although the clinical trial results and the guideline's indications, there is a need for safety and efficacy data from unselected patients in everyday clinical practice. Recently, a large number of studies testing the efficacy and the safety of TSOAs in clinical practice have been published. The aim of our article is to provide a concise review for clinicians, outlining the main studies that evaluated the efficacy and safety of TSOAs for thromboembolic stroke prevention in the real-world setting.

Overcoming global challenges in stroke prophylaxis in atrial fibrillation: The role of non-vitamin K antagonist oral anticoagulants

Atrial fibrillation is the world's most common sustained cardiac arrhythmia and is associated with a significantly increased risk of stroke. The global burden of atrial fibrillation is rising, commensurate with the ageing population. Well-controlled vitamin K antagonist-based anticoagulation has been shown to reduce the risk of stroke secondary to atrial fibrillation by two-thirds. However, patients with atrial fibrillation have frequently been denied anticoagulation because of a variety of perceived risks related to bleeding, falls, chronological age, and poor compliance. Even when vitamin K antagonists are used, maximum benefit and safety are only delivered when high quality control of therapy (TTR > 70%) is achieved, which has proven remarkably difficult in many health-care systems and amongst many patient groups. The non-vitamin K antagonist oral anticoagulants (NOACs) offer solutions to many of the challenges of achieving widespread, safe, and effective anticoagulation for stroke prophylaxis in atrial fibrillation, yet their uptake into routine clinical practice remains variable. The evidence supporting their more widespread use to overcome the challenges of stroke prophylaxis for atrial fibrillation is reviewed in this article.

Clinical and Economic Implications of Apixaban Versus Aspirin in the Low-Risk Nonvalvular Atrial Fibrillation Patients

BACKGROUND AND PURPOSE

Although recommended by guidelines, the benefits of treating patients with atrial fibrillation with a low-stroke risk score, with aspirin or anticoagulants, have not been clearly established. With advent of safer non-vitamin K antagonist oral anticoagulant, we assessed the clinical and economic implications of 5 mg BID of apixaban versus aspirin among patients with a relative low risk of stroke as assessed using the CHADS2 (congestive heart failure, hypertension, age>75, diabetes mellitus, stroke/transient ischemic attack) and CHA2DS2-VASc (congestive heart failure, hypertension, age, diabetes mellitus, stroke/transient ischemic attack, vascular disease) stroke risk classification.

METHODS

A previously developed and validated Markov model was adapted. A secondary analysis of the Apixaban Versus Acetylsalicylic Acid to Prevent Stroke in Atrial Fibrillation Patients Who Have Failed or Are Unsuitable for Vitamin K Antagonist Treatment (AVERROES) study was conducted to estimate event rates in different low-risk cohorts by treatment. Three cohorts (n=1000) with a CHADS2 score of 1, CHA2DS2-VASc score of 1, and CHA2DS2-VASc of score 2 to 4 were simulated to assess the number of clinical events avoided in terms of strokes and major bleeds, as well as life years gained, quality-adjusted life years gained, costs, and incremental costs per quality-adjusted life year gained.

RESULTS

Apixaban was associated with fewer strokes and systemic embolism versus aspirin across all subgroups; however, it caused more major bleeding events. The reduction in systemic embolism offset the increase in major bleeding events leading to increased life expectancy and quality-adjusted life year gains, achieved at an increased cost that was lower than the UK threshold of $44,400 (ie, £30,000) per quality-adjusted life year gained across the 3 cohorts examined.

CONCLUSIONS

Anticoagulant treatment with apixaban versus aspirin in low-risk patients, as identified using CHADS2 or CHA2DS2-VASc, is projected to increase life expectancy and provide clinical benefits that are cost effective.

New Oral Anticoagulants: How Do We Use Them Wisely?

The relative efficacy and safety of new oral anticoagulants (NOAC) have been consistent across a wide range of patients in clinical trials. On the one hand, they have offered new therapeutic options for stroke prevention in patients with atrial fibrillation (AF) and patients do like the experience of no need of frequent blood draws. On the other hand, their expensive prices, different formulary plans from different insurance companies, lack of antidote, and no method of monitoring the therapy are some of the challenges on their use in clinical practice. This narrative review aims to help clinicians understand these new oral anticoagulants better and choose them wisely according to their indications. In addition, other issues related to the use of NOAC, such as cost and methods of reversing their effects in hemorrhagic conditions, are also discussed.

Quality of anticoagulation control in preventing adverse events in patients with heart failure in sinus rhythm: Warfarin versus Aspirin in Reduced Cardiac Ejection Fraction trial substudy

BACKGROUND

The aim of this study is to examine the relationship between time in the therapeutic range (TTR) and clinical outcomes in heart failure patients in sinus rhythm treated with warfarin.

METHODS AND RESULTS

We used data from the Warfarin versus Aspirin in Reduced Cardiac Ejection Fraction (WARCEF) trial to assess the relationship of TTR with the WARCEF primary outcome (ischemic stroke, intracerebral hemorrhage, or death), with death alone, ischemic stroke alone, major hemorrhage alone, and net clinical benefit (primary outcome and major hemorrhage combined). Multivariable Cox models were used to examine how the event risk changed with TTR and to compare the high TTR, low TTR, and aspirin-treated patients, with TTR being treated as a time-dependent covariate. A total of 2217 patients were included in the analyses; among whom 1067 were randomized to warfarin and 1150 were randomized to aspirin. The median (interquartile range) follow-up duration was 3.6 (2.0-5.0) years. Mean (±SD) age was 61±11.3 years, with 80% being men. The mean (±SD) TTR was 57% (±28.5%). Increasing TTR was significantly associated with reduction in primary outcome (adjusted P<0.001), death alone (adjusted P=0.001), and improved net clinical benefit (adjusted P<0.001). A similar trend was observed for the other 2 outcomes, but significance was not reached (adjusted P=0.082 for ischemic stroke and adjusted P=0.109 for major hemorrhage).

CONCLUSIONS

In patients with heart failure in sinus rhythm, increasing TTR is associated with better outcome and improved net clinical benefit. Patients in whom good quality anticoagulation can be achieved may benefit from the use of anticoagulants.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00041938.

Selection of Warfarin or One of the New Oral Antithrombotic Agents for Long-Term Prevention of Stroke among Persons with Atrial Fibrillation

OPINION STATEMENT

Atrial fibrillation (AF) is the most common sustained cardiac rhythm disorder, which can potentially increases the risk of stroke by five-fold, thus, resulting in high public healthcare burden. Stroke prevention is vital in the management of AF patients. Vitamin K antagonists (VKA, eg, warfarin) have been the mainstay treatment to prevent ischemic stroke and systemic thromboembolism in AF patients for several decades. Despite the efficacy of warfarin, its limitations have recently driven the advent of some new antithrombotic agents, the non-VKA oral anticoagulant (NOACs, including dabigatran, rivaroxaban, apixaban, and edoxaban). The NOACs have changed the landscape for thromboembolic prophylaxis among patients with nonvalvular AF. Although three NOACs thus far (dabigatran, rivaroxaban, and apixaban) have been approved in Europe and the United States, for stroke prevention in patients with nonvalvular AF on the basis of several Phase III clinical trials, warfarin still remain important in preventing stroke for patients. This is especially true for those with optimal control of international normalized ratio with high (>70 %) time in therapeutic range, valvular AF or associated prosthetic valve. These NOACs are attractive alternatives for stroke prevention in patients with nonvalvular AF who are unable or unwilling to receive warfarin. However, several issues should be taken into consideration on safe and effective use of these NOACs in day-to-day clinical practice, for example, pharmacological properties, drug interactions, monitoring and compliance, and treatment of frail elderly patients or patients with renal impairment, etc. The decision about whether to initiate oral anticoagulation either with warfarin or NOACs should be patient-centered and after consideration of both stroke and bleeding risks. It is important for clinical practitioner to offer patients with AF an individualized decision about drug choice, making decision after adequate patient education plus discussion about the risks and benefits of these agents, thus fitting the drug to the patient profile.

The Health Impact Fund: how might it work for novel anticoagulants in atrial fibrillation?

Cardiovascular diseases represent the greatest burden of global disease. Spending on cardiovascular diseases is higher than for other diseases, with the majority being spent on drugs. Therefore, these drugs and these diseases are hugely important to health systems, society, and pharmaceutical companies. The Health Impact Fund represents a new mechanism by which pharmaceutical innovators would be rewarded on the basis of the health impact of their new drugs. This review illustrates the concept of the Health Impact Fund using the example of novel anticoagulants for prevention of stroke and thromboembolism in atrial fibrillation. By considering existing data and the current situation for novel anticoagulants, we suggest that epidemiologic data and modeling techniques can be used to predict future trends in disease and the health impact of new drugs. The Health Impact Fund may offer potential benefits to pharmaceutical companies, patients, and governments and warrants proper investigation.

Non-vitamin K antagonist oral anticoagulants (NOACs) for stroke prevention in Asian patients with atrial fibrillation: time for a reappraisal

Non-vitamin K antagonist oral anticoagulants (NOACs) have changed the landscape for stroke prevention in atrial fibrillation (AF). Given the huge burden of AF in Asians, more attention to stroke prevention is clearly needed. Aiming to provide an overview and reappraisal of stroke prevention in Asians with AF, we searched MEDLINE for information on NOACs in Asians. In addition, abstracts from national and international cardiovascular meetings were studied to identify unpublished studies. In the 4 recent Phase 3 trials comparing NOACs to warfarin, a consistent pattern is evident. For efficacy endpoints in the comparison of NOACs vs warfarin, a significant reduction in stroke/systemic embolization was seen for dabigatran 150mg [HR 0.45 (0.28-0.72)], with non-significant trends seen for lower stroke/systemic embolization with other NOACs, except edoxaban 30mg. A similar pattern was seen for ischaemic stroke, with a significant reduction for dabigatran 150mg [HR 0.55 (0.32-0.950]. For haemorrhagic stroke, all NOAC regimes, except rivaroxaban 20mg, had significantly lower hazard ratios. No evidence of increased myocardial infarction was found for NOACs. All-cause mortality was significantly lowered amongst Asian patients on edoxaban 60mg compared to warfarin [HR 0.63 (0.40-0.98)] with non-significant trends to lower mortality with dabigatran 150mg, rivaroxaban and edoxaban 30mg. For safety endpoints, all the NOAC regimes, except rivaroxaban 20mg, significantly reduced major bleeding and 'all bleeding' events. Intracranial haemorrhage was consistently lowered by all NOACs. None of NOACs increased gastrointestinal bleeding. These information suggested that NOACs should be preferentially indicated for stroke prevention in Asians with AF.

Increased risk of first-ever stroke in younger patients with atrial fibrillation not recommended for antithrombotic therapy by current guidelines: a population-based study in an East Asian cohort of 22 million people

OBJECTIVE

To assess the risk of first-ever ischemic stroke in younger patients with atrial fibrillation (AF) who have none of the CHA2DS2-VASc (congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, previous stroke/transient ischemic attack, vascular disease, age 65-74 years, sex category [female sex]) risk factors (excluding female sex) by using the National Health Insurance research database in Taiwan.

PATIENTS AND METHODS

From 22,842,778 insured people, we identified 24,612 hospitalized patients with newly diagnosed AF between January 1, 2002, and December 31, 2004, as the AF group and randomly selected 98,448 age- and sex-matched persons without AF as the non-AF group. Both groups were followed up until December 31, 2010, to estimate ischemic stroke incidences in relation to other stroke risk factors.

RESULTS

During a follow-up period of 89,468 person-years, the stroke rate was higher in patients with AF than in those without AF (5.79 per 100 person-years vs 2.25 per 100 person-years). The higher prevalence of CHA2DS2-VASc comorbidities (heart failure, hypertension, diabetes, coronary artery disease, and peripheral artery disease) in patients with AF further increased the stroke risk. In 790 patients with AF aged 30 to 55 years who had none of the CHA2DS2-VASc comorbidities at baseline and retained a "low risk," that is, those with a CHA2DS2-VASc score of 0 in men and 1 in women during follow-up, the stroke rate remained considerably higher than that in their non-AF counterparts (1.00 per 100 person-years vs 0.25 per 100 person-years), with a sex-adjusted hazard ratio of 4.09 (95% CI, 2.97-5.62).

CONCLUSION

This study finds an increased risk of stroke in younger patients with AF who are not recommended for prevention of thromboembolism by current guidelines. Better stroke risk stratification tools are needed to prioritize younger patients with AF for thromboprophylactic therapy in this population.

Warfarin versus dabigatran etexilate: an assessment of efficacy and safety in patients with atrial fibrillation

INTRODUCTION

Oral anticoagulation is the mainstay for stroke and thromboembolic event prevention in patients with atrial fibrillation (AF). Given limitations of warfarin therapy, non-vitamin K oral anticoagulants have been developed including direct thrombin inhibitors (i.e., dabigatran etexilate). Dabigatran etexilate has been tested thoroughly in terms of efficacy and safety in clinical trials and studies, involving 'real-world' cohorts. In this review, currently available evidence in patients with non-valvular AF is discussed.

AREAS COVERED

The pharmacology, efficacy and safety, and current aspects of use of dabigatran etexilate in patients with non-valvular AF are reviewed in a comparative manner to warfarin both for chronic anticoagulation and in different clinical settings.

EXPERT OPINION

Dabigatran etexilate appeared to have several pharmacokinetic and pharmacodynamic advantages over warfarin, as well as a favorable efficacy and safety profile being at least noninferior and often superior to warfarin in patients with non-valvular AF. The latter was shown in the clinical trials, meta-analyses and studies with 'real-world' data. Currently ongoing trials will expand the body of evidence on warfarin and will aid decision making in currently controversial areas. Important limitations of dabigatran etexilate include contraindications for its use in patients with prosthetic heart valves and end-stage chronic kidney disease.

Safety and efficacy of non-vitamin K oral anticoagulants in non-valvular atrial fibrillation: a Bayesian meta-analysis approach

INTRODUCTION

Choosing between different non-vitamin K antagonist oral anticoagulants (NOACs) in non-valvular atrial fibrillation (NVAF) is difficult due to the absence of head to head comparative studies. We performed a Bayesian meta-analysis to explore similarities and differences between different NOACs and to rank treatments overall for safety and efficacy outcomes.

AREAS COVERED

Through a systematic literature search we identified randomized controlled Phase III trials of dabigatran, rivaroxaban, apixaban, and edoxaban versus adjusted-dose warfarin in patients with NVAF.

EXPERT OPINION

Warfarin ranked worst for all-cause mortality and intracranial bleedings and had a nil probability of ranking first for any outcome. The risk of major bleeding versus warfarin was lower with apixaban, dabigatran 110 mg, and both doses of edoxaban. All agents reduced the risk of intracranial bleeding versus warfarin. Edoxaban 30 mg was the best among the treatments being compared for major and gastrointestinal bleeding. Dabigatran 150 mg was the best for stroke and systemic embolism. This study suggests that NOACs are generally preferable to warfarin in patients with NVAF. However, safety and efficacy differences do exist among NOACs, which might drive their use in specific subsets of AF patients, allowing prescribers to tailor treatment to distinct patient profiles.

'Real-world' antithrombotic treatment in atrial fibrillation: The EORP-AF pilot survey

BACKGROUND

Current guidelines strongly recommend that oral anticoagulation should be offered to patients with atrial fibrillation and ≥1 stroke risk factors. The guidelines also recommend that oral anticoagulation still should be used in the presence of stroke risk factors irrespective of rate or rhythm control.

METHODS

In an analysis from the dataset of the EURObservational Research Programme on Atrial Fibrillation Pilot Survey (n = 3119), we examined antithrombotic therapy prescribing, with particular focus on the risk factors determining oral anticoagulation or antiplatelet therapy use.

RESULTS

When oral anticoagulation was used among admitted patients in whom no pharmacologic cardioversion, electrical cardioversion, or catheter ablation was performed or planned, vitamin K antagonist therapy was prescribed in the majority (72.2%), whereas novel oral anticoagulants were used in the minority (7.7%). There was no significant difference in bleeding risk factors among the patients treated with the different types of antithrombotic therapies, except for those with chronic kidney disease, in whom oral anticoagulation was less commonly used (P = .0318). Antiplatelet therapy was more commonly used in patients with a high Hypertension, Abnormal renal/liver function, Stroke, Bleeding history or predisposition, Labile international normalized ratio, Elderly (>65 years), Drugs/alcohol concomitantly score (≥2) (P < .0001). More oral anticoagulation use was associated with female gender (P = .0245). Less novel oral anticoagulant use was associated with valvular heart disease (P < .0001), chronic heart failure (P = .0010), coronary artery disease (P < .0001), and peripheral artery disease (P = .0092). Coronary artery disease was the strongest reason for combination therapy with oral anticoagulation plus antiplatelet drug (odds ratio, 8.54; P < .0001). When the Congestive heart failure, Hypertension, Age ≥75 [Doubled], Diabetes, Stroke [Doubled]-Vascular disease, Age 65-74, and Sex category [female] score was used, 95.6% of patients with a score ≥1 received antithrombotic therapy, with 80.5% of patients with a score ≥1 receiving oral anticoagulation. Of note, 83.7% of those with a score ≥2 received antithrombotic therapy. Of the latter, 70.9% of those with a score ≥2 received oral anticoagulation, vitamin K antagonists were used in 64.1%, and novel oral anticoagulants were used in 6.9%.

CONCLUSIONS

The EURObservational Research Programme on Atrial Fibrillation Pilot Survey provides contemporary data on oral anticoagulation prescribing by European cardiologists for atrial fibrillation. Although the uptake of oral anticoagulation (mostly vitamin K antagonist therapy) has improved since the Euro Heart Survey a decade ago, antiplatelet therapy is still commonly prescribed, with or without oral anticoagulation, whereas elderly patients are commonly undertreated with oral anticoagulation.

Novel oral anticoagulants for stroke prevention in atrial fibrillation: results of the European Heart Rhythm Association survey

The purpose of this European Heart Rhythm Association (EHRA) survey was to assess clinical practice in relation to stroke prevention in atrial fibrillation (AF), particularly into the use of novel oral anticoagulants (NOACs) for stroke prevention, among members of the EHRA electrophysiology (EP) research network. In this EP Wire survey, we have provided some insights into current practice in Europe for the use of NOACs for stroke prevention in AF. There were clear practice differences evident, and also the need for greater adherence to the guidelines, especially since guideline adherent management results in better outcomes in AF.

Management of Atrial Fibrillation in Patients With Kidney Disease

The increasing burden of Chronic Kidney Disease (CKD) is highly relevant to cardiologists, as cardiovascular mortality is 10-30 times higher amongst people with End-stage Renal Disease (ESRD), comparing with general population. One of the commonest associations is the increased frequency of atrial fibrillation (AF) amongst those experiencing CKD. Overall, we know that AF is the most common cardiac arrhythmia. AF leads to a substantial risk of mortality and morbidity, from stroke and thromboembolism, heart failure, reduced cognitive function and impaired quality of life. However, most clinical trials in AF (for example, for stroke prevention in AF with anticoagulation therapy) have largely excluded patients with significant renal impairment. In this review article, we will focus on stroke prevention in AF, and the clinical impact of CKD and its implications for management.

Stroke And Bleeding Risk Assessment: Where Are We Now?

Atrial fibrillation (AF) is one of major problems of the contemporary cardiology. Ischaemic stroke is a common complication of the AF, and effective prophylaxis requires treatment with oral anticoagulants. The purpose of this current review article is to provide an overview of the various stroke and bleeding risk assessment scores that help decision making with respect to thromboprophylaxis. Particular focus is made on the currently guideline-recommended stroke and bleeding risk scores, such as CHA₂DS₂-VASc (congestive heart failure or left ventricular dysfunction, hypertension, age ≥75, diabetes, stroke, vascular disease, age 65-74 and sex category [female]) and HAS-BLED (uncontrolled hypertension, abnormal renal/liver function, stroke, bleeding history or predisposition, labile international normalized ratio, elderly [e.g. age >65, frail condition], drugs [e.g. aspirin, nonsteroidal anti-inflammatory drugs]/excessive alcohol) is made. Future directions for improvement of predictive ability of risk assessment with clinical factors and biomarkers are also discussed.

The economic burden to medicare of stroke events in atrial fibrillation populations with and without thromboprophylaxis

Some 3 million people in the United States have atrial fibrillation (AF). Without thromboprophylaxis, AF increases overall stroke risk 5-fold. Prevention is paramount as AF-related strokes tend to be severe. Thromboprophylaxis reduces the annual incidence of stroke in AF patients by 22%-62%. However, antithrombotics are prescribed for only about half of appropriate AF patients. The study team estimates the economic implications for Medicare of fewer stroke events resulting from increased thromboprophylaxis among moderate- to high-risk AF patients. The decision model used considers both reduced stroke and increased bleeding risk from thromboprophylaxis for a hypothetical cohort on no thromboprophylaxis (45%), antiplatelets (10%), and anticoagulation (45%). AF prevalence, stroke risk, and stroke risk reduction are adjusted for age, comorbidities, and anticoagulation/antiplatelet status. Health care costs are literature based. At baseline, an estimated 24,677 ischemic strokes, 9127 hemorrhagic strokes, and 9550 bleeding events generate approximately $2.63 billion in annual event-related health care costs to Medicare for every million AF patients eligible for thromboprophylaxis. A 10% increase in anticoagulant use in the untreated population would reduce stroke events by 9%, reduce stroke fatalities by 9%, increase bleed events by 5%, and reduce annual stroke/bleed-related costs to Medicare by about $187 million (7.1%) for every million eligible AF patients. A modest 10% increase in the use of thromboprophylaxis would reduce event-related costs to Medicare by 7.1%, suggesting a compelling economic motivation to improve rates of appropriate thromboprophylaxis. New oral anticoagulants offering better balance between the risks of stroke and major bleeding events may improve these clinical and economic outcomes.

Evaluation of patients' attitudes towards stroke prevention and bleeding risk in atrial fibrillation

Patient's values and preferences regarding the relative importance of preventing strokes and avoiding bleeding are now recognised to be of great importance in deciding on therapy for the prevention of stroke due to atrial fibrillation (SPAF). We used an iPad questionnaire to determine the minimal clinically important difference (Treatment Threshold) and the maximum number of major bleeding events that a patient would be willing to endure in order to prevent one stroke (Bleeding Ratio) for the initiation of antithrombotic therapy in 172 hospital in-patients with documented non-valvular atrial fibrillation in whom anticoagulant therapy was being considered. Patients expressed strong opinions regarding SPAF. We found that 12% of patients were "medication averse" and were not willing to consider antithrombotic therapy; even if it was 100% effective in preventing strokes. Of those patients who were willing to consider antithrombotic therapy, 42% were identified as "risk averse" and 15% were "risk tolerant". Patients required at least a 0.8% (NNT=125) annual absolute risk reduction and 15% relative risk reduction in the risk of stroke in order to agree to initiate antithrombotic therapy, and patients were willing to endure 4.4 major bleeds in order to prevent one stroke. In conclusion, there was a substantial amount of inter-patient variability, and often extreme differences in opinion regarding tolerance of bleeding risk in the context of stroke prevention in atrial fibrillation. These findings highlight the importance of considering patient preferences when deciding on SPAF therapy.

Age as a Risk Factor for Stroke in Atrial Fibrillation Patients: Implications in Thromboprophylaxis in the Era of Novel Oral Anticoagulants

Atrial fibrillation is associated with significant morbidity and mortality. There is a strong relationship between atrial fibrillation and aging, thromboembolism, stroke, congestive heart failure and hypertension. In addition, advanced age is a powerful risk factor for stroke and thromboembolism in patients with atrial fibrillation. For many years, vitamin K antagonists were the only approved anticoagulants for the management of atrial fibrillation. Lately new anticoagulants made their appearance and large trials have already shown their superiority against vitamin K antagonists. Since the arrhythmia is encountered frequently in the elderly, it is crucial to identify the beneficial effects of the novel oral anticoagulants in this particular patient population.