Choosing a particular oral anticoagulant and dose for stroke prevention in individual patients with non-valvular atrial fibrillation: part 1

Management of perioperative anticoagulation in patients with mechanical heart valve replacement undergoing laparoscopic cholecystectomy: a case report of postoperative cerebral embolism

Patients with mechanical heart valve replacement require lifelong anticoagulation therapy, and additional surgeries can pose a risk of bleeding and thromboembolic events due to the need for perioperative anticoagulation management. Here, we present a case report of a patient who underwent laparoscopic cholecystectomy (LC) and endoscopic retrograde cholangiopancreatography (ERCP) after mechanical heart valve replacement and experienced postoperative cerebral embolism. The management of perioperative anticoagulation in these patients is discussed, including strategies for minimizing the risks of bleeding and thromboembolic events during and after surgery.

Anticoagulation for Atrial Fibrillation in Patients with Decompensated Liver Cirrhosis: Bold and Brave?

Atrial fibrillation is frequently diagnosed in patients with liver cirrhosis, especially in those with non-alcoholic steatohepatitis or alcoholic etiology. Anticoagulant treatment is recommended for thromboembolic protection in patients with atrial fibrillation. Considering the impaired coagulation balance in liver cirrhosis, predisposing patients to bleed or thrombotic events, the anticoagulant treatment is still a matter of debate. Although patients with liver cirrhosis were excluded from the pivotal studies that confirmed the efficacy and safety of the anticoagulant treatment in patients with atrial fibrillation, data from real-life cohorts demonstrated that the anticoagulant treatment in patients with liver cirrhosis could be safe. This review aimed to evaluate the recent data regarding the safety and efficacy of anticoagulant treatment in patients with decompensated liver cirrhosis. Direct oral anticoagulants are safer than warfarin in patients with compensated liver cirrhosis. In Child-Pugh class C liver cirrhosis, direct oral anticoagulants are contraindicated. New bleeding and ischemic risk scores should be developed especially for patients with liver cirrhosis, and biomarkers for bleeding complications should be implemented in clinical practice to personalize this treatment in a very difficult population represented by decompensated liver cirrhosis patients.

Population Attributable Risks of Potential Modifiable Factors for Atrial Fibrillation in China: A National Survey

Background

There is an association between atrial fibrillation (AF) and overall mortality as well as mobility. It is not known, however, what the preventable burden of AF in China is. This study aims to identify what proportion of the burden of AF may be avoided by modifiable risk factors.

Methods

As part of the China National Stroke Screening and Prevention Project, 726,451 adults aged ≥40 years were enrolled in a representative cross-sectional study. The following seven factors have been categorized as modifiable risk factors for AF: body mass index, smoking, alcohol consumption, physical inactivity, hypertension, diabetes mellitus, and dyslipidemia. In order to calculate population-attributable risks (PARs), odds ratios (ORs) were calculated for selected risk factors.

Results

The crude ORs increased with age (ORs ranged from 1.92 to 4.02). A total of 18,736 cases of prevalent AF have been identified. The overall prevalence of AF was 2.6%. The crude ORs increased with age (ORs range 1.92–4.03). The adjusted ORs and the corresponding confidence intervals (CIs) for these seven modifiable factors were 1.16 (95% confidence interval [CI]: 1.12–1.19), 1.56 (95% CI: 1.49–1.62), 2.15 (95% CI: 2.02–2.28), 2.07 (95% CI: 2.01–2.14), 2.71 (95% CI: 2.62–2.79), 2.10 (95% CI: 2.02–2.19), 2.52 (95% CI: 2.44–2.60), and 3.32 (95% CI: 3.18–3.48), respectively. Accordingly, 59.3% of all cases of AF could be explained by having these modifiable risk factors, among which hypertension accounted for the greatest share.

Conclusion

In China, hypertension is the leading preventable cause of AF, and more than half of these cases can be prevented through improving those modifiable risk factors.

Non-Vitamin K Oral Anticoagulant After Transcatheter Aortic Valve Replacement: A Systematic Review and Meta-Analysis

Objective: We aimed to compare non-vitamin K oral anticoagulants (NOACs) with a traditional antithrombotic such as vitamin K antagonist (VKA) and antiplatelet agents in patients after transcatheter aortic valve replacement (TAVR). Methods: We conducted a search in PubMed, EMBASE, and the Cochrane Library until November 2021 for studies involving comparisons of any type of NOACs, including dabigatran, apixaban, rivaroxaban, and edoxaban, with VKA or antiplatelet agents after TAVR. A comparison of NOACs versus VKA was performed in patients with an indication for oral anticoagulation. In addition, we compared NOACs versus antiplatelet in patients without such indication. We calculated the hazard ratios with 95% confidence intervals (CIs) to determine long-term outcomes. The primary outcome was a combined endpoint consisting of all-cause mortality, stroke, major bleeding, or any related clinical adverse events. Secondary outcomes were all-cause mortality, major bleeding, and stroke, respectively. Results: A total of 10 studies including 10,563 patients after TAVR were included in this meta-analysis. There were no significant differences in any of the long-term outcomes between the NOAC and VKA groups. Although there were no significant differences in the combined endpoint, major bleeding, or stroke, a significant difference was observed in the all-cause mortality (HR 1.74, 95% CI 1.25-2.43, p = 0.001) between the NOAC and antiplatelet groups. Conclusion: For patients with an indication for oral anticoagulation after TAVR, NOACs seem to be associated with noninferior outcomes compared with VKA therapy. However, for patients without an indication for oral anticoagulation, NOACs appear to be associated with a higher risk of all-cause death as compared with antiplatelet treatment. Systematic Review Registration: https://clinicaltrials.gov/, identifier CRD42020155122.

Atrial fibrillation: a geriatric perspective on the 2020 ESC guidelines

BACKGROUND

The Task Force for the diagnosis and management of atrial fibrillation (AF) of the European Society of Cardiology (ESC) published in 2020 the updated Guidelines for the Diagnosis and Management of Atrial Fibrillation with the contribution of the European Heart Rhythm Association (EHRA) of the ESC and the European Association for Cardiothoracic Surgery (EACTS).

METHODS AND RESULTS

In this narrative viewpoint, we approach AF from the perspective of aging medicine and try to provide the readers with information usually neglected in clinical routine, mainly due to the fact that while the large majority of AF patients in real life are older, frail and cognitively impaired, these are mostly excluded from clinical trials, and physicians' attitudes often prevail over standardized algorithms.

CONCLUSIONS

On the basis of existing evidence, (1) opportunistic AF screening by pulse palpation or ECG rhythm strip is cost-effective, and (2) whereas advanced chronological age by itself is not a contraindication to AF treatment, a Comprehensive Geriatric Assessment (CGA) including frailty, cognitive impairment, falls and bleeding risk may assist in clinical decision making to provide the best individualized treatment.

Prevention of ischemic stroke in atrial fibrillation from the point of view of a neurologist. Standards and real clinical practice

The article outlines aspects of the current state of the problem of the priority choice of an oral anticoagulant for indefinite prevention of stroke and systemic thromboembolism in patients with atrial fibrillation. The advantages of direct oral angicoagulants over warfarin are presented, as well as a comparative analysis of the individual characteristics of the main direct oral angicoagulants from the point of view of personification of preventive therapy in accordance with modern treatment standards. The efficacy and safety of oral anticoagulant therapy has been reviewed in terms of the net clinical benefit. Particular attention is paid to the age-related aspects of choosing an anticoagulant for indefinite prophylaxis; an assessment of anticoagulants is presented in accordance with the FORTA concept, which regulates the use of drugs in elderly patients. In conclusion, recommendations are formulated for the choice of an anticoagulant in patients with atrial fibrillation in the most common clinical situations. As a general rule, the choice of a particular drug should be individualized based on risk factors, tolerability, net clinical benefit, patient preference, potential adverse interactions, and other clinical characteristics.

Spinal Cord Compression Secondary to a Spontaneous Spinal Haematoma in a Patient Newly Treated with Rivaroxaban

A 74-year-old patient anticoagulated with rivaroxaban for chronic atrial fibrillation presented to the emergency department with acute lumbar pain with progressive weakness of the lower limbs and inability to stand up. No previous trauma was reported. Neurological examination was consistent with a complete spinal cord syndrome at the level of T6. Magnetic resonance imaging showed the presence of spinal cord compression associated with signs of extensive intramedullary inflammation secondary to a haematoma. The patient underwent thoracic laminectomy with evacuation of an intradural haematoma. No intraoperative complications were described, but no clinical improvement had been achieved 15 days after the surgical intervention.

LEARNING POINTS

Apixaban could be preferred as the first choice for direct oral anticoagulation (DOAC) in older patients.DOACs can have important side effects even if the switch from vitamin K antagonist to this group is correctly carried out.

Appropriate Dosing Regimens of Non-Vitamin K Antagonist Oral Anticoagulants for Treatment of Patients With Non-Valvular Atrial Fibrillation: An Evidence-Based Consideration

Patients with non-valvular atrial fibrillation (NVAF) exhibit a high risk of stroke, which is associated with high mortality. Thus, stroke prevention is crucial for the overall management of NVAF. Two categories of drugs, vitamin K antagonist warfarin and non-vitamin K antagonist oral anticoagulants (NOACs), are clinically used to prevent NVAF-related stroke. In some circumstances, NOACs are superior to warfarin. However, NOACs selection for NVAF patients is affected by many factors, including individual patient characteristics, comorbidities, risk factors, or laboratory variables. This article summarizes the discrepancy in NOACs management with emphasis on the dosing regimens and influencing factors, such as stroke risk, age, body weight, renal function, gastrointestinal bleeding (GIB) risk, and combination of antiplatelet therapy, in order to identify individual groups with particular clinical characteristics who may obtain more benefit from a certain dosing regimen of NOACs. Determination of a particular subset of patient populations for the appropriate dose regimen of NOACs will help to achieve desired clinical outcomes. Furthermore, to compensate clinical evidence, we should place more emphasis on the findings of current clinical trials and supplement real-world data.

Oral Anticoagulation

BACKGROUND

Much new evidence on oral anticoagulation has come to light in recent years. Non-vitamin-K-dependent oral anti- coagulants (NOAC) have been developed and have been introduced into clinical practice. In this review, we present the current state of the evidence on anticoagulation for various indications with vitamin K antagonists (VKA) and with NOAC.

METHODS

This review is based on pertinent articles retrieved by a selective search in PubMed (search terms: anticoagulation, atrial fibrillation, prosthetic valve, thrombosis, pulmonary embolism) and on specialty society recommendations and relevant guidelines from the years 2000-2018.

RESULTS

The main indications for oral anticoagulation are atrial fibrillation, venous thromboembolism, and status post heart valve replacement. In patients with atrial fibrillation and without valvular heart disease, anticoagulation is recommended for men with a CHA2DS2-VASc score ≥ 1 and for women with a score ≥ 2. NOAC for this indication are associated with a marginally lower rate of stroke than VKA (3.5% vs. 3.8%, number needed to treat [NNT] = 333) as well as a lower rate of major hemorrhage (5.1% vs. 6.2%, NNT = 91). NOAC are contraindicated for patients with mechanical heart valves. Anticoagulation with VKA can be predictably antagonized. Among the various types of NOAC, the anticoagulant effect of dabigatran can be safely antagonized with an antidote; no specific antidote is yet available for apixaban, rivaroxaban, or edoxaban.

CONCLUSION

The evidence base for anticoagulation over a time frame of several years is inadequate at present, and direct comparative data for the different types of NOAC are not yet available.

Safety of Using Direct Oral Anticoagulants in Patients with Atrial Fibrillation and Chronic Kidney Disease

The purpose of this review is to examine the possibilities and prospects for the use of direct oral anticoagulants for the prevention of thromboembolic complications in patients with atrial fibrillation and chronic kidney disease. Chronic kidney disease is an independent risk factor for cardiovascular complications. Atrial fibrillation is associated with a higher risk of developing chronic kidney disease and more rapid progression of existing renal pathology. The presence of chronic kidney disease in atrial fibrillation on the one hand leads to an increased risk of thromboembolism, and on the other to an increased risk of bleeding when using anticoagulants. The standard for the prevention of thromboembolic complications in atrial fibrillation, including those with concomitant renal pathology, was considered warfarin for many years. However, modern studies have shown that the use of warfarin may enhance vascular calcification in patients with chronic kidney disease, which in turn may lead to an increased risk of ischemic strokes.

Analyzing clinical recommendations, randomized studies, meta-analyzes and a systematic review on the use of anticoagulants in patients with atrial fibrillation and renal pathology, revealed the advantage of using direct oral anticoagulants over warfarin at stage 1-3 of chronic kidney disease. Data on the use of direct oral anticoagulants with a more pronounced renal dysfunction and in patients on dialysis is limited due to the lack of a sufficient number of large randomized studies. Due to the presence of renal clearance in all oral anticoagulants, their pharmacokinetics changes to some extent with a decrease in the glomerular filtration rate, which requires dose adjustment of drugs depending on creatinine clearance. Therefore, the use of anticoagulants for the prevention of thromboembolic complications during atrial fibrillation requires special attention in patients with chronic kidney disease.

Predictors of new oral anticoagulant drug initiation as opposed to warfarin in elderly adults: a retrospective observational study in Southern Italy

AIM

The aim of this study was to assess the predictive role of age, gender, and number and type of co-treatments for new oral anticoagulant (NOAC) vs warfarin prescription in elderly patients naïve for the aforementioned drugs.

MATERIALS AND METHODS

Data collected in the period from January 1, 2014, to December 31, 2014, in Caserta Local Health Unit administrative databases (Campania Region, Italy) were screened to identify new users of oral anticoagulants (OACs) who were 75 years or older and whose OAC prescriptions amounted to >90 days of treatment. Age, gender, and number and type of concomitant medications at the time of first OAC dispensation were retrieved. Multivariable logistic regression analysis was used to assess the role of the aforementioned predictors for NOAC initiation as opposed to warfarin.

RESULTS

Overall, 2,132 incident users of OAC were identified, of whom 967 met all inclusion criteria. In all, 490 subjects (50.7%) received an NOAC and 477 (49.3%) received warfarin. Age >75 years was positively associated with lower odds of NOAC initiation (OR: 0.969, 95% CI: 0.941-0.998, P=0.038). Similarly, multiple concomitant medication was negatively associated with NOAC initiation compared to warfarin (OR [five to nine drugs] group: 0.607, 95% CI: 0.432-0.852, P=0.004; OR [ten+ drugs] group: 0.372, 95% CI: 0.244-0.567, P<0.001). Prior exposure to platelet aggregation inhibitor drugs was associated with the initiation of NOACs (OR: 3.474, 95% CI: 2.610-4.625).

CONCLUSION

Age and multiple co-medication were negatively associated with NOAC initiation.

Thromboprophylaxis for Patients with High-risk Atrial Fibrillation and Flutter Discharged from the Emergency Department

Introduction

Many patients with atrial fibrillation or atrial flutter (AF/FL) who are high risk for ischemic stroke are not receiving evidence-based thromboprophylaxis. We examined anticoagulant prescribing within 30 days of receiving dysrhythmia care for non-valvular AF/FL in the emergency department (ED).

Methods

This prospective study included non-anticoagulated adults at high risk for ischemic stroke (ATRIA score ≥7) who received emergency AF/FL care and were discharged home from seven community EDs between May 2011 and August 2012. We characterized oral anticoagulant prescribing patterns and identified predictors of receiving anticoagulants within 30 days of the index ED visit. We also describe documented reasons for withholding anticoagulation.

Results

Of 312 eligible patients, 128 (41.0%) were prescribed anticoagulation at ED discharge or within 30 days. Independent predictors of anticoagulation included age (adjusted odds ratio [aOR] 0.89 per year, 95% confidence interval [CI] 0.82–0.96); ED cardiology consultation (aOR 1.89, 95% CI [1.10–3.23]); and failure of sinus restoration by time of ED discharge (aOR 2.65, 95% CI [1.35–5.21]). Reasons for withholding anticoagulation at ED discharge were documented in 139 of 227 cases (61.2%), the most common of which were deferring the shared decision-making process to the patient’s outpatient provider, perceived bleeding risk, patient refusal, and restoration of sinus rhythm.

Conclusion

Approximately 40% of non-anticoagulated AF/FL patients at high risk for stroke who presented for emergency dysrhythmia care were prescribed anticoagulation within 30 days. Physicians were less likely to anticoagulate older patients and those with ED sinus restoration. Opportunities exist to improve rates of thromboprophylaxis in this high-risk population.

Navigating the choice of oral anticoagulation therapy for atrial fibrillation in the NOAC era

Atrial fibrillation (AF) is a major cause of ischaemic stroke. The majority of these strokes can be prevented by treatment with oral anticoagulation therapy. The advent of non-vitamin K antagonist oral anticoagulants (NOACs) has resulted in a choice of therapeutic agents available to physicians for anticoagulation for stroke prevention in patients with AF beyond the long-established vitamin K antagonists (VKAs). Pivotal trials have demonstrated non-inferiority of NOACs compared with VKAs, and in some cases superiority, for the prevention of stroke and systemic embolism in non-valvular AF. Yet there are no direct head-to-head comparator trials for the efficacy of NOACs. Therefore, the question of which oral anticoagulant for each individual patient can present a challenge to physicians. In this review article, we assess which patients with AF require anticoagulation, review the available therapeutic options, assessing the evidence base for each and offering guidance as to patient-specific factors that can influence this choice.

Evolving cardiovascular uses of direct-acting oral anticoagulants: a paradigm shift on the horizon?

Direct-acting oral anticoagulants (DOACs), by virtue of pharmacological properties perceived as innovative, are changing the therapeutic scenario of patients requiring short- and long-term anticoagulation. The evidence gathered so far (from pre-approval pivotal trials to real-world post-marketing observational data) consistently confirms that DOACs are overall comparable to vitamin-K antagonists (VKAs) in terms of safety, efficacy, effectiveness and unequivocally documents a clinically relevant reduced risk of intracranial bleeding in the settings of non-valvular atrial fibrillation (AF) and venous thromboembolism. The following issues are attracting considerable clinical interest: (a) identifying specific subpopulations of patients with AF most likely to benefit from one of these agents (the so-called tailored therapy), and (b) expanding therapeutic indications in emerging diseases characterized by arterial and venous thromboembolic risk. In these scenarios, the risk-benefit profile of DOACs, as compared to VKAs or heparins, is still incompletely characterized. In cardiology, the challenging task of selecting a suitable or even the most appropriate DOAC for patients with AF and a particular phenotype prompted experts to provide suggestions based on careful review of subgroups of patients from pivotal RCTs. However, in the past few months, variegated multicenter trials have been published (RE-CIRCUIT, PIONEER-AF-PCI, GEMINI-ACS-1), with potential influence on clinical practice. Therefore, this review aims to update the latest evidence on the evolving therapeutic uses of DOACs in the cardiovascular area, addressing potential impact for clinicians.

Efficacy and Safety of Uninterrupted Low-Intensity Warfarin for Radiofrequency Catheter Ablation of Atrial Fibrillation in the Elderly

Background: No previous studies exist investigating the optimal intensity of uninterrupted anticoagulation with warfarin during radiofrequency catheter ablation (RFCA) for atrial fibrillation (AF) in the elderly. Objective: Evaluate the efficacy and safety of continuous low-intensity warfarin therapy throughout the periprocedural period of RFCA for AF in the elderly. Methods: This is a prospective randomized study. We enrolled AF patients (age ≥ 70 years) who underwent first-time RFCA for AF. Enrolled patients were randomized to group A and group B. The international normalized ratios before ablation were maintained at 1.5 to 2.0 and 2.0 to 2.5 in group A and B, respectively. Primary end points were periprocedural thromboembolic complications and major bleeding. Secondary end points included periprocedural asymptomatic cerebral emboli (ACE) and minor bleeding. Results: A total of 101 patients were enrolled in our study (group A: 52; group B: 49). Baseline characteristics were well balanced between the 2 groups. Only 1 patient suffered from stroke in group B. No major bleeding events occurred in either group. The incidence of new ACE lesions was comparable between the 2 groups (11.5% vs 8.2%, P = 0.82). Minor bleeding occurred in 1 of 52 (1.9%) patients in group A and in 5 of 49 (10.2%) patients in group B ( P = 0.10). Conclusions: Uninterrupted low-intensity warfarin for RFCA of AF might be as effective as standard-intensity warfarin in preventing periprocedural thromboembolic complications and might be associated with fewer bleeding events in the elderly.

New frontiers in anticoagulation: non vitamin-K oral anticoagulants in stroke prevention

INTRODUCTION

Non vitamin-K oral anticoagulants (NOACs) are direct and specific inhibitors of the coagulation factors IIa (dabigatran) and Xa (apixaban, rivaroxaban, edoxaban) which share many pharmacokinetic properties. However, indications are lacking regarding the use of NOACs during thrombolysis, surgery and bleeding events. Areas covered: In this paper, the authors retrospectively analyzed the relevant literature on the NOACs using the PubMed and Google Scholar databases. Expert commentary: Although warfarin is effective in cardioembolic stroke prevention, easier handling and more favorable risk-benefit profile often render NOACs a more preferable therapy choice for neurologists. New evidences have suggested their use in treatment of elderly people, in patients with renal insufficiency or with antiphospholipid antibody syndrome. In addition, the use of antidotes, which rapidly reverse the anticoagulant effect of the NOACs, could be useful in bleeding, during emergency procedures, or in case of overdose.

Risk-Benefit Profile of Direct-Acting Oral Anticoagulants in Established Therapeutic Indications: An Overview of Systematic Reviews and Observational Studies

Since 2008, the direct-acting oral anticoagulants (DOACs) have expanded the therapeutic options of cardiovascular diseases with recognized clinical and epidemiological impact, such as non-valvular atrial fibrillation (NVAF) and venous thromboembolism (VTE), and also in the preventive setting of orthopedic surgical patients. The large body of evidence, not only from pivotal clinical trials but also from 'real-world' postmarketing observational findings (e.g. analytical epidemiological studies and registry data) gathered to date allow for a first attempt at verifying a posteriori whether or not the pharmacological advantages of the DOACs actually translate into therapeutic innovation, with relevant implications for clinicians, regulators and patients. This review aims to synthesize the risk-benefit profile of DOACs in the aforementioned consolidated indications through an 'evidence summary' approach gathering the existent evidence-based data, particularly systematic reviews with meta-analyses of randomized controlled trials, as well as observational studies, comparing DOACs with vitamin K antagonists. Clinical evidence will be discussed and compared with major international guidelines to identify whether an update is needed. Controversial clinically relevant safety issues will be also examined in order to highlight current challenges and unsettled questions (e.g. actual bleeding risk in susceptible populations). It is anticipated that the large number of publications on NVAF or VTE (44 systematic reviews with meta-analyses and 12 observational studies retained in our analysis) suggests the potential existence of overlapping studies and calls for common criteria to qualitatively and quantitatively assess discordances, thus guiding future research.

New Oral Anticoagulants in Nonvalvular Atrial Fibrillation

The choice of an oral anticoagulant (OAC) for patients with nonvalvular atrial fibrillation (NVAF) is a major and complex clinical decision taking into account the individual risk-benefit ratio and bearing in mind the chronicity of therapy. This review focuses on the safety and efficacy of new oral anticoagulants (NOACs) compared with conventional vitamin K antagonists (VKA) in patients with NVAF. Current data suggest that NOACs are at least as effective and safe as VKAs for most NVAF subjects. The NOACs do not mandate dietary restrictions and regular pharmacodynamic monitoring, and they seem to have lesser incidence of intracranial or fatal bleeding when compared with VKAs. However, both dabigatran 150 twice daily and rivaroxaban have a slightly higher incidence of gastrointestinal bleeding when compared with VKAs. The article will delineate the current knowledge as well as scientific gaps related to the choice and dosage of anticoagulation regimens for various NVAF subsets and will address certain common clinical scenarios requiring special considerations. The article also addresses the shortcomings of NOACs: lack of therapeutic pharmacokinetic and pharmacodynamic targets, absence of tools to assess compliance and efficacy, rigid and limited dosage options, and absence of effective and inexpensive reversal agents.

Comparative effectiveness and safety of non-vitamin K antagonist oral anticoagulants and warfarin in patients with atrial fibrillation: propensity weighted nationwide cohort study

OBJECTIVE

 To study the effectiveness and safety of the non-vitamin K antagonist oral anticoagulants (novel oral anticoagulants, NOACs) dabigatran, rivaroxaban, and apixaban compared with warfarin in anticoagulant naïve patients with atrial fibrillation.

DESIGN

 Observational nationwide cohort study.

SETTING

 Three Danish nationwide databases, August 2011 to October 2015.

PARTICIPANTS

 61 678 patients with non-valvular atrial fibrillation who were naïve to oral anticoagulants and had no previous indication for valvular atrial fibrillation or venous thromboembolism. The study population was distributed according to treatment type: warfarin (n=35 436, 57%), dabigatran 150 mg (n=12 701, 21%), rivaroxaban 20 mg (n=7192, 12%), and apixaban 5 mg (n=6349, 10%).

MAIN OUTCOME MEASURES

 Effectiveness outcomes defined a priori were ischaemic stroke; a composite of ischaemic stroke or systemic embolism; death; and a composite of ischaemic stroke, systemic embolism, or death. Safety outcomes were any bleeding, intracranial bleeding, and major bleeding.

RESULTS

 When the analysis was restricted to ischaemic stroke, NOACs were not significantly different from warfarin. During one year follow-up, rivaroxaban was associated with lower annual rates of ischaemic stroke or systemic embolism (3.0% v 3.3%, respectively) compared with warfarin: hazard ratio 0.83 (95% confidence interval 0.69 to 0.99). The hazard ratios for dabigatran and apixaban (2.8% and 4.9% annually, respectively) were non-significant compared with warfarin. The annual risk of death was significantly lower with apixaban (5.2%) and dabigatran (2.7%) (0.65, 0.56 to 0.75 and 0.63, 0.48 to 0.82, respectively) compared with warfarin (8.5%), but not with rivaroxaban (7.7%). For the combined endpoint of any bleeding, annual rates for apixaban (3.3%) and dabigatran (2.4%) were significantly lower than for warfarin (5.0%) (0.62, 0.51 to 0.74). Warfarin and rivaroxaban had comparable annual bleeding rates (5.3%).

CONCLUSION

 All NOACs seem to be safe and effective alternatives to warfarin in a routine care setting. No significant difference was found between NOACs and warfarin for ischaemic stroke. The risks of death, any bleeding, or major bleeding were significantly lower for apixaban and dabigatran compared with warfarin.

Effectiveness and Safety of Dabigatran, Rivaroxaban, and Apixaban Versus Warfarin in Nonvalvular Atrial Fibrillation

BACKGROUND

The introduction of non-vitamin K antagonist oral anticoagulants has been a major advance for stroke prevention in atrial fibrillation; however, outcomes achieved in clinical trials may not translate to routine practice. We aimed to evaluate the effectiveness and safety of dabigatran, rivaroxaban, and apixaban by comparing each agent with warfarin.

METHODS AND RESULTS

Using a large US insurance database, we identified privately insured and Medicare Advantage patients with nonvalvular atrial fibrillation who were users of apixaban, dabigatran, rivaroxaban, or warfarin between October 1, 2010, and June 30, 2015. We created 3 matched cohorts using 1:1 propensity score matching: apixaban versus warfarin (n=15 390), dabigatran versus warfarin (n=28 614), and rivaroxaban versus warfarin (n=32 350). Using Cox proportional hazards regression, we found that for stroke or systemic embolism, apixaban was associated with lower risk (hazard ratio [HR] 0.67, 95% CI 0.46-0.98, P=0.04), but dabigatran and rivaroxaban were associated with a similar risk (dabigatran: HR 0.98, 95% CI 0.76-1.26, P=0.98; rivaroxaban: HR 0.93, 95% CI 0.72-1.19, P=0.56). For major bleeding, apixaban and dabigatran were associated with lower risk (apixaban: HR 0.45, 95% CI 0.34-0.59, P<0.001; dabigatran: HR 0.79, 95% CI 0.67-0.94, P<0.01), and rivaroxaban was associated with a similar risk (HR 1.04, 95% CI 0.90-1.20], P=0.60). All non-vitamin K antagonist oral anticoagulants were associated with a lower risk of intracranial bleeding.

CONCLUSIONS

In patients with nonvalvular atrial fibrillation, apixaban was associated with lower risks of both stroke and major bleeding, dabigatran was associated with similar risk of stroke but lower risk of major bleeding, and rivaroxaban was associated with similar risks of both stroke and major bleeding in comparison to warfarin.