Which Oral Anticoagulant for Which Atrial Fibrillation Patient: Recent Clinical Trials and Evidence-Based Choices

Predictors of NOAC versus VKA use for stroke prevention in patients with newly diagnosed atrial fibrillation: Results from GARFIELD-AF

INTRODUCTION

A principal aim of the Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) was to document changes in treatment practice for patients with newly diagnosed atrial fibrillation during an era when non-vitamin K antagonist oral anticoagulants (NOACs) were becoming more widely adopted. In these analyses, the key factors which determined the choice between NOACs and vitamin K antagonists (VKAs) are explored.

METHODS

Logistic least absolute shrinkage and selection operator regression determined predictors of NOAC and VKA use. Data were collected from 24,137 patients who were initiated on AC ± antiplatelet (AP) therapy (NOAC [51.4%] or VKA [48.6%]) between April 2013 and August 2016.

RESULTS

The most significant predictors of AC therapy were country, enrolment year, care setting at diagnosis, AF type, concomitant AP, and kidney disease. Patients enrolled in emergency care or in the outpatient setting were more likely to receive a NOAC than those enrolled in hospital (OR 1.16 [95% CI: 1.04-1.30], OR: 1.15 [95% CI: 1.05-1.25], respectively). NOAC prescribing seemed to be favored in lower-risk groups, namely, patients with paroxysmal AF, normotensive patients, and those with moderate alcohol consumption, but also the elderly and patients with acute coronary syndrome. By contrast, VKAs were preferentially used in patients with permanent AF, moderate to severe kidney disease, heart failure, vascular disease, and diabetes and with concomitant AP.

CONCLUSION

GARFIELD-AF data highlight marked heterogeneity in stroke prevention strategies globally. Physicians are adopting an individualized approach to stroke prevention where NOACs are favored in patients with a lower stroke risk but also in the elderly and patients with acute coronary syndrome.

Predicted risk of stroke and bleeding and use of oral anticoagulants in atrial fibrillation: Danish nationwide temporal trends 2011-2016

INTRODUCTION, MATERIALS AND METHODS

We used Danish nationwide registries to examine temporal trends in the predicted stroke and bleeding risks (mean CHA₂DS₂-VASc and HAS-BLED scores per year, respectively) as well as the combination of selected stroke and bleeding risk factors per year among atrial fibrillation (AF) patients initiated for the first time between 2011 and 2016 on vitamin K antagonists (VKAs), dabigatran, rivaroxaban, or apixaban.

RESULTS

In total, 53,860 AF patients were included (VKA 37.7%, dabigatran 24.4%, rivaroxaban 16.9%, apixaban 21.0%). For standard dose dabigatran initiators, during almost all of the study period, the mean CHA₂DS₂-VASc and HAS-BLED scores were the lowest and decreased (2.6 and 2.2 in 2011 vs. 2.1 and 1.8 in 2016, respectively). Reduced dose apixaban initiators had rather stable mean CHA₂DS₂-VASc scores during the study period and the highest mean CHA₂DS₂-VASc score in 2016 (4.1). The mean HAS-BLED scores were similarly high among reduced dose apixaban and rivaroxaban initiators in years 2013-2016. From 2011 to 2014, a decrease in the frequency of prior stroke (p<0.001), age≥75years (p<0.001), and prior bleeding (p=0.007) was observed among dabigatran initiators. In the study period, apixaban initiators in general had the highest frequency of prior stroke and age≥75years.

CONCLUSIONS

Danish AF patients receiving standard dose dabigatran had the lowest and decreasing predicted stroke and bleeding risks during almost all study years. Patients receiving reduced dose apixaban had rather stable predicted risk of stroke during the study period and the highest mean CHA₂DS₂-VASc score in 2016.

The evolving role of dabigatran etexilate in clinical practice

INTRODUCTION

Stroke and venous thromboembolism (VTE) affect millions of patients. The vitamin K antagonist, warfarin, has been the main oral anticoagulant used to treat these conditions despite many limitations associated with its use. Recently, multiple novel oral anticoagulants have been approved and are reshaping how patients with atrial fibrillation (AF) at risk of stroke and patients with VTE are treated. The direct thrombin inhibitor, dabigatran etexilate , is among these novel agents that have been developed to overcome limitations with warfarin.

AREAS COVERED

In this article, authors describe the pharmacokinetic and pharmacodynamic properties of dabigatran etexilate and summarize the clinical evidence and controversy surrounding its use in the US, Canada and Europe.

EXPERT OPINION

Dabigatran has demonstrated similar efficacy and safety to enoxaparin for VTE prevention in patients undergoing hip and knee arthroplasty, and to warfarin for the treatment of VTE. Dabigatran (110 mg) is noninferior and dabigatran (150 mg) is superior to warfarin for stroke prevention in patients with nonvalvular AF, with a lower rate of intracranial hemorrhage reported at both doses. Apixaban, rivaroxaban and edoxaban provide alternate anticoagulant options to dabigatran. While there are many similarities, there are also significant differences to consider in agent selection based on patient-specific characteristics.

[Oral anticogulation for non-valvular atrial fibrilation in the elderly]

Anticoagulation in elderly people with non-valvular atrial afibrillation (AF) is a challenge, due to the thromboembolic, as well as the haemorrhagic risks. The correct use of anticoagulants in these patients has shown a higher net clinical benefit when comparing it with a younger population. Non-vitamin K antagonist oral anticoagulants (NOACs) have been compared to oral vitamin K antagonists in several studies that included a sufficient number of elderly people. Favourable results for non-vitamin K antagonist oral anticoagulants were obtained in these studies, making them the preferred treatment for this group of patients. Basing the estimations on indirect comparisons, the ideal anticoagulant and the specific dose for each particular case has been determined. Finally, a new algorithm has been developed that relates these parameters. Geriatric assessment is the key to the indication for an anticoagulation, the type of anticoagulant needed, and also the best way to optimise all the factors for a safe anticoagulation. The arrival of non-vitamin K antagonist oral anticoagulants will enhance the efficient thromboembolic prophylaxis rate in elderly people with AF. This new treatment will remove different controversial prophylaxis, such as antiaggregants.

[Stroke prevention after stroke in patients with atrial fibrillation: a case-based review]

Non-valvular atrial fibrillation is one of the most important risk factor for embolic cerebral infarcts. Besides vitamin K antagonists, recently developed novel oral anticoagulants are gaining an increasing role in its treatment. Dabigatran, rivaroxaban and apixaban are novel oral anticoagulants available in the routine clinical practice. This review summarizes their use and the corresponding guidelines in the secondary prevention of ischemic stroke, by answering questions raised in relation of a hypothetical case report.