Novel oral anticoagulants in non-valvular atrial fibrillation

A Comprehensive Review of Percutaneous and Surgical Left Atrial Appendage Occlusion

Atrial fibrillation (AF) is the most common arrhythmia worldwide, and is associated with a significant risk of thromboembolic events. Left atrial appendage occlusion (LAAO) has emerged as a promising alternative for patients with contraindications or intolerance to anticoagulant therapy. This review summarises the current evidence, indications, and technical advancements in surgical and percutaneous LAAO. Preprocedural planning relies on various imaging techniques, each with unique advantages and limitations. The existing randomised clinical trials and meta-analyses demonstrate favourable results for both percutaneous and surgical LAAO. Postprocedural management emphasises personalised anticoagulation strategies and comprehensive imaging surveillance to ensure device stability and detect complications. Future focus should be put on antithrombotic regimens, investigating predictors of device-related complications, and simplifying procedural aspects to enhance patient outcomes. In summary, LAAO is presented as a valuable therapeutic option for preventing AF-related thromboembolic events, with ongoing research aimed at refining techniques and improving patient care.

Prevention of Pulmonary and Venous Thromboembolism Post Coronary Artery Bypass Graft Surgery - Literature Review

Objective

The current review evaluates recent literature on the different aspects of prophylaxis in postoperative pulmonary and venous thromboembolism and their main risk factors.

Methods

The literature survey was carried out based on the PubMed data using the keywords “coronary artery bypass graft” and “venous thromboembolism” as components of the search field title.

Results

Studies reported several risk factors for postoperative thromboembolism including advanced age, postoperative immobilization, type of thromboprophylaxis, obesity, and location of the surgery.

Conclusion

According to the studies, tailored prophylaxis could be easily adapted to decrease the intensity and duration of postoperative thromboembolism in a patient with several disorders and comorbidities, especially in cardiovascular disease.

Stroke and Systemic Thromboembolism Prevention in People Living With Human Immunodeficiency Virus With Atrial Fibrillation: A Review of Its Implications for Clinical Practice

In the last few decades, types of diseases affecting people living with human immunodeficiency virus (PLHIV) have shifted as the population ages, with cardiovascular disease becoming a leading cause of death in this population. Atrial fibrillation (AF) is an increasingly common arrhythmia both in the general population and in PLHIV, with an estimated prevalence of 2% to 3% among PLHIV. Prevention of stroke and systemic thromboembolism (SSE) with antithrombotic therapy is a cornerstone of AF treatment and substantially decreases AF-related morbidity and mortality. Although updated guidelines extensively discuss this issue, they do not address the peculiarities of PLHIV. The role of human immunodeficiency virus (HIV) infection as an independent factor for SSE in individuals with AF and whether the presence of HIV should alter the threshold for SSE thromboprophylaxis are unknown. Nevertheless, a growing body of evidence describes the increasing burden of comorbidities such as hypertension and stroke in PLHIV, which predispose them to AF and SSE. In the absence of HIV-specific AF guidelines, PLHIV with AF should be comprehensively assessed for their risk of SSE and bleeding using commonly available scores despite them having been primarily validated in the non-HIV population. Both vitamin K antagonists and direct oral anticoagulants can be used in PLHIV. Addressing HIV-related comorbidities and potential drug-drug interactions with antiretrovirals is crucial to prevent SSE and reduce adverse reactions of oral anticoagulants. This review summarizes the current guidelines for SSE prevention in patients with AF and describes key considerations for their implementation among PLHIV receiving antiretroviral therapy.

Trends in initiation of direct oral anticoagulant therapies for atrial fibrillation in a national population-based cross-sectional study in the French health insurance databases

OBJECTIVE

Unlike several other national health agencies, French health authorities recommended that the newer direct oral anticoagulant (DOAC) agents only be prescribed as second choice for the treatment of newly diagnosed non-valvular atrial fibrillation (NVAF), with vitamin K antagonists (VKA) remaining the first choice. We investigated the patterns of use of DOACs versus VKA in the treatment of NVAF in France over the first 5 years of DOAC availability. We also identified the changes in patient characteristics of those who initiated DOAC treatment over this time period.

METHODS

Based on the French National Health Administrative Database, we constituted a population-based cohort of all patients who were newly treated for NVAF between January 2011 and December 2015. Trends in drug use were described as the percentage of patients initiating each drug at the time of treatment initiation. A multivariate analysis using logistic regression model was performed to identify independent sociodemographic and clinical predictors of initial anticoagulant choice.

RESULTS

The cohort comprised 814 446 patients who had received a new anticoagulant treatment for NVAF. The proportion of patients using DOACs as initial anticoagulant therapy reached 54% 3 months after the Health Ministry approved the reimbursement of dabigatran for NVAF, and 61% by the end of 2015, versus VKA use. In the multivariate analysis, we found that DOAC initiators were younger and healthier overall than VKA initiators, and this tendency was reinforced over the 2011-2014 period. DOACs were more frequently prescribed by cardiologists in 2012 and after (adjusted OR in 2012: 2.47; 95% CI 2.40 to 2.54).

CONCLUSION

Despite recommendations from health authorities, DOACs have been rapidly and massively adopted as initial therapy for NVAF in France. Observational studies should account for the fact that patients selected to initiate DOAC treatment are healthier overall, as failure to do so may bias the risk-benefit assessment of DOACs.

Efficacy and safety of edoxaban in comparison with dabigatran, rivaroxaban and apixaban for stroke prevention in atrial fibrillation

Large Phase 3 clinical trials for stroke prevention in atrial fibrillation (AF) have compared non-vitamin K antagonist oral anticoagulants (NOACs) against warfarin, with the edoxaban trial only recently reported. In the absence of head to head trials directly comparing these NOACs against each other, we compared the efficacy and safety of edoxaban to other agents by an indirect comparison analysis. We performed an indirect comparison analysis of edoxaban (2 dose strategies) against apixaban (1 dose), dabigatran etexilate (2 doses) and rivaroxaban (1 dose), for their relative efficacy and safety against each other. For high-dose edoxaban vs apixaban, there were no significant differences in efficacy endpoints, mortality, myocardial infarction and major bleeding. Apixaban was associated with less major or clinically relevant non-major bleeding (hazard ratio [HR] 0.79; 95% confidence interval [CI] 0.70–0.90) and gastrointestinal bleeding (HR 0.72; 95% CI 0.53–0.99). For dabigatran 110 mg twice daily, there were no significant differences in the main efficacy or safety endpoints. Dabigatran 150 mg bid was associated with lower stroke/systemic embolism (SE) (HR 0.75; 95% CI 0.56–0.99), stroke (HR 0.73; 95% CI 0.55–0.96) and haemorrhagic stroke (HR 0.48; 95% CI 0.23–0.99). There were no significant differences between high-dose edoxaban vs rivaroxaban for efficacy endpoints or mortality, but rivaroxaban had more major and/or clinically relevant non-major bleeding. When compared to low-dose edoxaban, apixaban was associated with lower stroke/SE (HR 0.70; 95% CI 0.55–0.89), stroke (HR 0.70; 95% CI 0.55–0.92) and ischaemic stroke (HR 0.65; 95% CI 0.50–0.89), but more major bleeding (HR 1.47; 95% CI 1.20–1.80). For dabigatran 110 mg bid, there were no significant differences in the efficacy endpoints, but dabigatran 110 mg bid had higher major (and gastrointestinal) bleeding. Dabigatran 150 mg bid and rivaroxaban were associated with lower stroke/SE and ischaemic stroke, but higher bleeding rates. In the present analysis, we have provided for the first time, comparisons of efficacy and safety of edoxaban against other NOACs. Notwithstanding the significant limitations of an indirect comparison analysis, some differential effects are evident with the NOACs for stroke prevention, allowing us to allow the prescriber a ‘choice’ to be able to fit the drug to the patient clinical profile (and vice versa).

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

Costs of major intracranial, gastrointestinal and other bleeding events in patients with atrial fibrillation - a nationwide cohort study

Background

Use of oral anticoagulation therapy in patients with atrial fibrillation (AF) involves a trade-off between a reduced risk of ischemic stroke and an increased risk of bleeding events. Different anticoagulation therapies have different safety profiles and data on the societal costs of both ischemic stroke and bleeding events are necessary for assessing the cost-effectiveness and budgetary impact of different treatment options. To our knowledge, no previous studies have estimated the societal costs of bleeding events in patients with AF.

The objective of this study was to estimate the 3-years societal costs of first-incident intracranial, gastrointestinal and other major bleeding events in Danish patients with AF.

Methods

The study was an incidence-based cost-of-illness study carried out from a societal perspective and based on data from national Danish registries covering the period 2002-2012. Costs were estimated using a propensity score matching and multivariable regression analysis (first difference OLS) in a cohort design.

Results

Average 3-years societal costs attributable to intracranial, gastrointestinal and other major bleeding events were 27,627, 17,868, and 12,384 EUR per patient, respectively (2015 prices). Existing evidence shows that the corresponding costs of ischemic stroke were 24,084 EUR per patient (2012 prices). The average costs of bleeding events did not differ between patients with AF who were on oral anticoagulation therapy prior to the event and patients who were not.

Conclusions

The societal costs attributable to major bleeding events in patients with AF are significant. Intracranial haemorrhages are most costly to society with average costs of similar magnitude as the costs of ischemic stroke. The average costs of gastrointestinal and other major bleeding events are lower than the costs of intracranial haemorrhages, but still substantial. Knowledge about the relative size of the costs of bleeding events compared to ischemic stroke in patients with AF constitutes valuable evidence for decisions-makers in Denmark as well as in other countries.

Electronic supplementary material

The online version of this article (doi:10.1186/s12913-017-2331-z) contains supplementary material, which is available to authorized users.

Emerging Tools for Stroke Prevention in Atrial Fibrillation

Ischaemic strokes resulting from atrial fibrillation (AF) constitute a devastating condition for patients and their carers with huge burden on health care systems. Prophylactic treatment against systemic embolization and ischaemic strokes is the cornerstone for the management of AF. Effective stroke prevention requires the use of the vitamin K antagonists or non-vitamin K oral anticoagulants (NOACs). This article summarises the latest developments in the field of stroke prevention in AF and aims to assist physicians with the choice of oral anticoagulant for patients with non-valvular AF with different risk factor profile.

Novel oral anticoagulants in non-valvular atrial fibrillation

Atrial fibrillation is the most frequent arrhythmia in clinical practice, reaching 2% of the people in the world and is associated with systemic embolism. Thus, the use of anticoagulants is indicated if CHA2DS2-VASc score ≥ 2 or in patients with previous transient ischemic attack or stroke. For decades, warfarin, a vitamin K antagonist, was the only choice for chronic oral anticoagulation. Recently, novel oral anticoagulants (NOACs) have been introduced, offering similar (or better) effectiveness, safety, and convenience to the vitamin K antagonists. Dabigatran was the first NOAC approved and is a direct thrombin inhibitor. Rivaroxaban and apixaban are factor Xa inhibitors. They display rapid onset of action, more predictable of pharmacological profile, less interactions with other drugs, lack of significant effects in the diet, and less risk of intracranial hemorrhage than warfarin. Despite that dose adjustment is necessary for patients with chronic kidney disease or according to body weight, these new drugs do not require regular monitoring. There are recommendations for the start and follow-up therapy with NOACs, planning for cardioversion, ablation and surgical interventions and the management of bleeding. This article is a review of the major studies of the NOACs. The clinical use of these drugs in patients with non-valvular atrial fibrillation is presented.

Factors driving anticoagulant selection in patients with atrial fibrillation in the United States

With the introduction of novel oral anticoagulants (NOACs), the factors driving anticoagulant selection in atrial fibrillation (AF) in real-world practice are unclear. The goal was to examine whether and to what extent utilization has been driven by predictions of stroke risk (treatment benefit), bleeding risk (treatment harm), or prescription benefits' coverage. We extracted a cohort of patients with nonvalvular AF initiating anticoagulation from October 2010 to December 2012 from a large US database of commercial and Medicare supplement claims. Multivariable regression examined associations between ischemic stroke (CHA2DS2-VASc) and bleeding (Anticoagulation and Risk Factors in Atrial Fibrillation [ATRIA]) risk scores and benefits' generosity (proportion of costs covered by patients relative to total) with warfarin and novel oral anticoagulant (NOAC) selection and also between dabigatran and rivaroxaban. C-statistics and partial chi-square statistics were used to assess the variation explained. Of 70,498 patients initiating anticoagulation, 29.9% and 7.9% used dabigatran and rivaroxaban, respectively. Compared with warfarin, patients were less likely to receive an NOAC with high ischemic stroke risk (CHA2DS2-VASc ≥2; adjusted relative risk [aRR] 0.75, 95% confidence interval [CI] 0.72 to 0.77) and high bleeding risk (ATRIA ≥5; aRR 0.66, 95% CI 0.64 to 0.69) but more likely with good benefits' generosity (≤20% of costs borne by patient; aRR 2.03, 95% CI 1.92 to 2.16). Prescription generosity explained almost twice the model variation as either risk score. Compared with dabigatran, patients were more likely to fill rivaroxaban with high bleeding risk (aRR 1.16, 95% CI 1.09 to 1.24). In conclusion, patients with greater bleeding and ischemic stroke risk were more likely to initiate warfarin, but generous benefits more strongly predicted NOAC usage and drove more selection.

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.

The newer direct oral anticoagulants: a practical guide

Anticoagulation therapy is one of the most important advances in modern medicine, saving thousands of lives from the complications of atrial fibrillation and mechanical heart valves and preventing recurrent venous thromboembolism. Warfarin and heparins have been the predominant anticoagulants used until the past decade. However, the arrival of newer target-specific anticoagulants has brought us easier and equally effective agents, although no specific antidotes are yet available. Being relatively newer drugs, physicians need to be familiar with the various practical issues that may be encountered with the prescription of these drugs, which are summarised in this review.