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

Prescription of DOACs in Patients with Atrial Fibrillation at Different Stages of Renal Insufficiency

Atrial fibrillation (AF) and renal insufficiency often coexist and are increasingly prevalent with advancing age. Both the risk of thromboembolic events and bleeding propensity are higher in patients with AF and impaired renal function versus those with good renal health. Direct oral anticoagulants (DOACs) are being increasingly preferred over vitamin K antagonists (VKAs) in the treatment of patients with AF and impaired renal function as VKAs may accelerate progression of chronic kidney disease. DOACs, however, are eliminated by the kidneys to varying degrees, and their dosages must be adapted in accordance with renal function. Since creatinine clearance (CrCl) monitoring is recommended in patients with AF receiving DOAC therapy, CrCl must be routinely monitored in patients at the start and during the course of anticoagulation to avoid deviation from Summary of Product Characteristics dosage specifications. This review article provides an overview of current knowledge on the selection and dose of DOACs including apixaban, dabigatran, edoxaban and rivaroxaban in AF patients at different stages of renal insufficiency, with a special focus on elderly patients with comorbidities and receiving multiple medications. The groups discussed in this review include patients with varying levels of CrCl including hyperfiltration or CrCl > 90 ml/min, CrCl < 90-50 ml/min, CrCl < 50-30 ml/min, CrCl < 30-15 ml/min and end-stage renal disease or on dialysis.

Use of Oral Anticoagulants in Patients with Atrial Fibrillation: Preliminary Data from the Italian Atrial Fibrillation (ITALY-AF) Registry

BACKGROUND

Atrial fibrillation (AFIB), the most frequent cardiac arrhythmia, is a major risk factor for stroke, heart failure, and death. Because of the recent advances in AFIB management and the availability of new oral anticoagulants (OACs), there is a need for a systematic and predefined collection of contemporary data regarding its management and treatment.

METHODS

The objective of the ongoing ITALY-AFIB registry is to evaluate the long-term morbidity and mortality in patients with AFIB and to verify the implementation of the current guidelines for stroke prevention in these patients. The registry includes consecutive in- and out-patients with first diagnosed, paroxysmal, persistent, or permanent AFIB. In patients in sinus rhythm at entry, the qualifying episode of AFIB, confirmed by ECG diagnosis, had to have occurred within 1 year before entry. The clinical record form is web-based and accessible by personal keyword.

RESULTS

Enrolment into the registry started in the year 2013. In a current cohort of 2470 patients (mean age 75 ± 11 years, males 56%), the mean CHA2DS2-VASc score was 3.7 ± 1.8, and the mean HAS-BLED was 1.6 ± 0.9. There were no significant sex differences in the AFIB subtypes. At the end of the inclusion visit and after receiving knowledge of the web-based electronic estimate of risk for stroke and bleeding, the proportion of patients discharged with OACs was 80%. After exclusion of patients with first diagnosed AFIB (n = 397), the proportion of patients with prescription of OACs rose from 66% before the visit to 82% on discharge (p < 0.0001). Prescription of aspirin or other antiplatelet drugs fell from 18% before the visit to 10% on discharge (p < 0.0001).

CONCLUSIONS

A web-based management of AFIB with automated estimation of risk profiles appears to favorably affect adherence to AFIB guidelines, based on a high proportion of patients treated with OACs and a substantial decline in the use of antiplatelet drugs.

Risk of Intracranial Hemorrhage Caused by Direct Oral Anticoagulants for Stroke Prevention in Patients With Atrial Fibrillation (from a Network Meta-Analysis of Randomized Controlled Trials)

Patients with atrial fibrillation (AF) who take direct oral anticoagulants (DOACs) face the risk of intracranial hemorrhage (ICH), which can be serious and even life threatening, but the risk of ICH of anticoagulants is still controversial. In this meta-analysis, we compared the risk of ICH between vitamin K antagonists (VKAs) and DOACs. Furthermore, we also compared the risk of ICH in different DOACs. PubMed, Embase, Web of Science, and the Cochrane Library were searched for relevant randomized controlled trials. The outcome was ICH, shown as the odds ratio (OR) with a 95% confidence interval (CI). DOACs were ranked by calculating the surface under the cumulative ranking curve (SUCRA). We included a total of 82,404 patients with AF. DOACs reduced the ICH risk by nearly half compared with VKAs (OR 0.47, 95% CI 0.40 to 0.54, p <0.001). VKAs were the least safe among all oral anticoagulants (SUCRA 1.7). Dabigatran 110 mg was the safest DOAC (SUCRA 87.3) for ICH risk, whereas rivaroxaban 20 mg was a relatively unsafe DOAC (SUCRA 27.5). Compared with rivaroxaban 20 mg, dabigatran 110 mg presented 53% (OR 0.47, 95% CI 0.27 to 0.82) lower relative risk for ICH. In conclusion, DOACs present less ICH risk than VKAs in patients with AF. For patients with AF who are at high risk of ICH, dabigatran 110 mg may be the safest choice among the DOACs.

Non-inferiority Trial Design in Drug Development: A Primer for Cardiovascular Healthcare Professionals

Noninferiority trials, in which a new treatment is compared with a standard active treatment, are becoming increasingly popular in cardiovascular medicine. A noninferiority trial seeks to test whether the effect of a new drug is not unacceptably worse than that of an active comparator by more than a predefined noninferiority margin. Noninferiority trials are typically used when a new drug is anticipated to have an efficacy profile similar to its comparator and offers advantages over the existing drug (better toxicity profile, less expensive, less invasive, simpler regimen, shorter treatment duration, different resistance profile). Given the high number of noninferiority trials, it is vital that clinicians fully understand the clinical impacts of the results. Nonetheless, assessing noninferiority in a trial is complex, in both the design and the analysis phases. The crucial issue in the design of a noninferiority trial is the definition of the noninferiority margin, accounting for both statistical (summarizing the historical evidence of the active comparator from randomized controlled trials) and clinical (choosing the fraction of the effect of the old drug that should be "preserved" by the new drug) considerations. We review the role of noninferiority trials in the development of new cardiovascular treatments and discuss a variety of key issues involved in the design and conduction of noninferiority trials, using some examples from real clinical trials in cardiovascular medicine.

Efficacy and Safety of Non-Vitamin K Anticoagulants for Atrial Fibrillation in Relation to Different Renal Function Levels: A Network Meta-Analysis

Background

We performed a network meta-analysis (NMA) comparing the efficacy (stroke or systemic embolism) and safety (major bleeding) among different non-vitamin K antagonist oral anticoagulants (NOACs) in patients with atrial fibrillation (AF) and renal impairment, with the aim of recommending the proper drug and the dose based on renal function.

Methods

We searched PubMed, EMBASE, Web of Science, and Cochrane Library with the items “dabigatran, edoxaban, apixaban, rivaroxaban, warfarin, and atrial fibrillation” through August 2019. NMA was analyzed with R (version 3.5.1, R Foundation for Statistical Computing) with the packages gemtc recalling JAGS (version 4.3.0) for the efficacy and safety of each drug with regard to different levels of renal function. NetMetaXL (version 1.6.1) and winBUGS (version 1.4.3) were used to obtain the cumulative ranking curve (SUCRA) of each drug.

Result

In patients with normal renal function, dabigatran150 was ranked as the most effective drug (SUCRA 0.90), followed by dabigatran110 (SUCRA 0.68), apixaban (SUCRA 0.66), and rivaroxaban (SUCRA 0.59). With regard to the safety for preventing major bleeding, there was high probability that edoxaban30 (SUCRA 0.99) ranked first, compared to dabigatran110 (SUCRA 0.78) and edoxaban60 (SUCRA 0.66). For patients with mild renal impairment, with respect to the most effective drug for preventing stroke or systemic embolism, edoxaban60 ranked first (SUCRA 0.98), in comparison with dabigatran150 (SUCRA 0.74) and apixaban (SUCRA 0.64). Possibility of ranking first for the safest drug was edoxaban30 (SUCRA 0.99), followed by dabigatran110 (SUCRA 0.70) and apixaban (SUCRA 0.69). In patients with moderate renal function, dabigatran150 (SUCRA 0.95) ranked as the most effective drug in comparison with apixaban (SUCRA 0.66). Dabigatran110 (SUCRA 0.53), rivaroxaban (SUCRA 0.51), and edoxaban60 (SUCRA 0.50) had the similar probability of ranking third. When referred to the safest drug, probability of ranking first for preventing major bleeding was edoxaban30 (SUCRA 0.98), followed by apixaban (SUCRA 0.85) and edoxaban60 (SUCRA 0.64).

Conclusion

In patients with AF and renal impairment and for patients with normal renal function, dabigatran 110 mg (bid) might have a better effect on the clinical results. And it does not coincide with patients taking dabigatran 110 mg with dose reduction for other factors including aged ≥75 years, renal impairment (CrCL 30–50 mL/min), gastritis, esophagitis, or gastroesophageal reflux, receiving concomitant verapamil, and so on. For patients with mild renal impairment, apixaban 5 mg (bid) would be a better choice for preventing stroke or systemic embolism and major bleeding, while apixaban 5 mg (bid) and edoxaban 60 mg (qd) were recommended for patients with moderate renal impairment. However, considering the fact of no RCTs for the head-to-head comparison, caution should be exercised over selecting each of NOACs for patients.

Type 2 Valvular Heart Disease Affects Decision Making for Anticoagulation in Patients with Atrial Fibrillation: The UMBRIA-Fibrillazione Atriale Prospective Study

Background  Valvular heart disease (VHD) and atrial fibrillation (AF) often coexist.

Aim  We investigated whether type 2 VHD (other than moderate-severe rheumatic mitral stenosis or mechanical heart valve) influences the prescription of anticoagulants in AF.

Methods  Umbria-Fibrillazione Atriale is a prospective multicenter registry in patients with AF. For the purpose of this study, type 2 VHD patients were propensity matched with non-VHD counterparts in a 1:1 ratio. Patients with type 1 VHD (moderate-severe mitral stenosis or mechanical heart valve) were excluded.

Results  We identified 2,212 patients with AF and excluded 46 because data on VHD were unavailable. Type 2 VHD was present in 426 patients (19.7%). Before registry entry visit, 77.1% of type 2 VHD and 66.8% of non-VHD patients were on anticoagulants. At discharge, 90.8 and 85.2% of patients, respectively, were on anticoagulants. After propensity-score matching, 386 patient-pairs were created. In the matched sample, the likelihood of being on anticoagulants before (odds ratio [OR]: 1.43, 95% confidence interval [CI]: 1.02–2.01, p  = 0.036) and after (1.63, 95% CI: 1.04–2.57, p  = 0.034) the entry visit was higher in type 2 VHD than in non-VHD patients. Patients with type 2 VHD were 70% more likely to receive vitamin K antagonists (VKAs) (OR: 1.70, 95% CI: 1.28–2.27, p  < 0.001), and 32% less likely to receive non–vitamin K oral anticoagulants (NOACs; OR: 0.68, 95% CI: 049–0.94, p  = 0.011) than non-VHD patients.

Conclusion  VKAs consistently outperformed NOACs as preferred treatment option in patients with type 2 VHD. This could potentially deny to these patients the well-established benefits of NOACs observed in phase III trials.

A systematic review and Bayesian network meta-analysis of risk of intracranial hemorrhage with direct oral anticoagulants

Essentials Risk of intracranial hemorrhage (ICH) may differ between direct oral anticoagulants (DOACs). We compared the risk of ICH between DOACs using network meta-analysis. Dabigatran 110 mg and 150 mg were safer than rivaroxaban on Bayesian analysis. Dabigatran 110 mg ranked as the safest DOAC while rivaroxaban ranked last.

SUMMARY

Background The comparative risk of intracranial hemorrhage (ICH) among direct oral anticoagulants (DOACs) (dabigatran, rivaroxaban, apixaban and edoxaban) remains unclear. Objective To determine the difference in risk of ICH between DOACs Methods Seventeen randomized controlled trials (RCTs) were selected using PubMed/MEDLINE, EMBASE and CENTRAL (Inception, 31 December 2017). Estimates were reported as odds ratio (OR) with 95% credible interval (CR.I) in Bayesian network meta-analysis (NMA), and OR with 95% confidence interval (CI) in traditional meta-analyses. Relative ranking probability of each group was generated based on surface under the cumulative ranking curve (SUCRA). Results In NMA of 116 618 patients from 17 RCTs (apixaban = 19 495 patients, rivaroxaban = 14 157 patients, dabigatran = 16 074 patients, edoxaban = 11 652 patients, and comparator = 55 315 patients), all DOACs were safer than warfarin for risk of ICH. Dabigatran 110 mg ranked as the safest drug (SUCRA, 0.85) and reduced the risk of ICH by 56% compared to rivaroxaban (OR, 0.44; 95% Cr.I, 0.22-0.82). Pairwise meta-analysis validated these findings, showing that DOACs were safer than warfarin (OR, 0.46; 95% CI, 0.35-0.59). Subgroup analysis showed that the benefit was present when DOACs were used in non-valvular atrial fibrillation (NVAF) (OR, 0.51; 95% CI, 0.38-0.68) or venous thromboembolism (VTE) (OR, 0.32; 95% CI, 0.18-0.58). Conclusion Dabigatran 110 mg may be the safest choice among any anticoagulant regarding risk of ICH. Both dabigatran 110 mg and 150 mg were safer than rivaroxaban.

Comparison of major bleeding risk in patients with non-valvular atrial fibrillation receiving direct oral anticoagulants in the real-world setting: a network meta-analysis

OBJECTIVE

To conduct a systematic literature review (SLR) and network meta-analysis (NMA) of real-world studies comparing major bleeding risk among patients with non-valvular atrial fibrillation (NVAF) on direct oral anticoagulants (DOACs) or warfarin.

METHODS

Systematic searches were conducted in MEDLINE and Embase for full-text articles published between January 1, 2003 and March 18, 2017. Eligible studies compared at least two of the following in a real-world setting: warfarin, apixaban, dabigatran, rivaroxaban, or edoxaban. A Bayesian NMA was conducted to estimate hazard ratios (HRs) for major bleeding using a random-effects model.

RESULTS

Eleven studies were included in the NMA. Nine studies included DOACs vs Warfarin comparisons, and four studies included DOACs vs DOACs comparisons (two studies included both comparisons). Median follow-up duration ranged from 2.6-31.2 months. No evidence was identified for edoxaban. Apixaban was associated with a significantly lower risk of major bleeding compared to other oral anticoagulants (warfarin HR = 0.58; 95% credible interval [CrI] = 0.48-0.69; dabigatran = 0.73; 0.61-0.87; rivaroxaban = 0.55; 0.46-0.66). Dabigatran was associated with a significantly lower risk than warfarin (0.79; 0.71-0.88) and rivaroxaban (0.76; 0.67-0.85), and rivaroxaban was not statistically different from warfarin (1.05; 0.91-1.19). Sensitivity analyses with standard dose and sponsorship showed consistent results.

CONCLUSION

DOACs were associated with lower or similar risk of major bleeding compared with warfarin in NVAF patients. Apixaban was associated with a significantly lower risk of major bleeding than other DOACs. Dabigatran was associated with a significantly lower risk of major bleeding compared to rivaroxaban and warfarin.

Comparison of Oral Anticoagulants for Stroke Prevention in Nonvalvular Atrial Fibrillation: A Multicriteria Decision Analysis

BACKGROUND

Decision on the most appropriate oral anticoagulation therapy for stroke prevention in patients with nonvalvular atrial fibrillation is difficult because multiple treatment options are available, and these vary in their clinical effects and relevant nonclinical characteristics.

OBJECTIVES

To use a multicriteria decision analysis (MCDA) to compare the oral anticoagulants apixaban, dabigatran, edoxaban, rivaroxaban, and vitamin K antagonist (VKAs; specifically warfarin) in patients with nonvalvular atrial fibrillation.

METHODS

We identified the evaluation criteria through a targeted literature review and clinical judgment. The final evaluation model included nine clinical events and four other criteria. We ranked possibly fatal clinical event criteria on the basis of the differences in risks of fatal events and the corresponding window of therapeutic opportunity, as observed in clinical trials. Clinical judgment was used to rank other criteria. Full criteria ranking was used to calculate centroid weights, which were combined with individual treatment performances to estimate the overall value score for each treatment.

RESULTS

Using such an MCDA, dabigatran yielded the highest overall value, approximately 6% higher than that of the second-best treatment, apixaban. Dabigatran also had the highest first-rank probability (0.72) in the probabilistic sensitivity analysis. Rivaroxaban performed worse than the other non-VKA oral anticoagulants, but better than VKAs (with both having 0.00 first-rank probability). The results were insensitive to changes in model structure.

CONCLUSIONS

When all key oral anticoagulant value criteria and their relative importance are investigated in an MCDA, dabigatran appears to rank the highest and warfarin the lowest.

Is it reasonable to use a lower DOAC dose in some patients with VTE? NO

The international guidelines recommend the use of direct oral anticoagulants (DOACs) over vitamin K antagonists for anticoagulation long-term therapy in patients diagnosed with venous thromboembolism (VTE), and for stroke prevention in patients with non-valvular atrial fibrillation (AF). Efficacy and safety of DOACS have been extensively evaluated in large phase III trials. According to the product label, dose reductions of DOACs are recommended for patients with AF and renal impairment, low body weight and concomitant use of interfering medications. Except for Edoxaban, dose reductions of DOACs are not recommended in patients with VTE based on the same indications for AF patients. The aim of this article is to discuss the indication of a lower DOAC dose in some patients with VTE. Observational studies and randomized control trials (RCTs) show that patients with AF are usually older, more often have chronic diseases, and more often are treated with several concomitant medications, potentially increasing their haemorrhagic risk. Furthermore, many VTE patients need a shorter period of anticoagulation therapy than AF patients. In real-life studies, VTE patients treated with inappropriate DOAC doses present a higher rate of VTE recurrence, and the same risk of bleeding compared to those treated with the correct dose. In light of this evidence, the use of lower DOAC dose in patients with VTE does not appear reasonable and may be potentially dangerous.

Exploratory Network Meta Regression Analysis of Stroke Prevention in Atrial Fibrillation Fails to Identify Any Interactions with Treatment Effect

Background

Patients with atrial fibrillation are at a greater risk of stroke and therefore the main goal for treatment of patients with atrial fibrillation is to prevent stroke from occurring. There are a number of different stroke prevention treatments available to include warfarin and novel oral anticoagulants. Previous network meta-analyses of novel oral anticoagulants for stroke prevention in atrial fibrillation acknowledge the limitation of heterogeneity across the included trials but have not explored the impact of potentially important treatment modifying covariates.

Objectives

To explore potentially important treatment modifying covariates using network meta-regression analyses for stroke prevention in atrial fibrillation.

Methods

We performed a network meta-analysis for the outcome of ischaemic stroke and conducted an exploratory regression analysis considering potentially important treatment modifying covariates. These covariates included the proportion of patients with a previous stroke, proportion of males, mean age, the duration of study follow-up and the patients underlying risk of ischaemic stroke.

Results

None of the covariates explored impacted relative treatment effects relative to placebo. Notably, the exploration of ‘study follow-up’ as a covariate supported the assumption that difference in trial durations is unimportant in this indication despite the variation across trials in the network.

Conclusion

This study is limited by the quantity of data available. Further investigation is warranted, and, as justifying further trials may be difficult, it would be desirable to obtain individual patient level data (IPD) to facilitate an effort to relate treatment effects to IPD covariates in order to investigate heterogeneity. Observational data could also be examined to establish if there are potential trends elsewhere. The approach and methods presented have potentially wide applications within any indication as to highlight the potential benefit of extending decision problems to include additional comparators outside of those of primary interest to allow for the exploration of heterogeneity.

Implications of edoxaban in the prevention and treatment of thromboembolic complications in clinical practice

Edoxaban is a once-daily oral inhibitor of factor Xa, currently indicated to reduce the risk of stroke or systemic embolism in nonvalvular atrial fibrillation patients and for the treatment and prevention of venous thromboembolism (EMA, FDA and Japan). The ENGAGE AF-TIMI 48 and the Hokusai-VTE trials demonstrated that edoxaban was at least as effective as warfarin for the prevention of stroke or systemic embolism in nonvalvular atrial fibrillation patients, as well as for the prevention and treatment of venous thromboembolism, but with a lesser risk of bleeding in both cases. In addition, it seems a cost-effective strategy for the management of this population. In this review, the implications of the most recent available evidence about edoxaban in clinical practice will be updated.

Suboptimal Use of Oral Anticoagulants in Atrial Fibrillation: Has the Introduction of Direct Oral Anticoagulants Improved Prescribing Practices?

BACKGROUND AND OBJECTIVES

Atrial fibrillation (AF) and the associated risk of stroke are emerging epidemics throughout the world. Suboptimal use of oral anticoagulants for stroke prevention has been widely reported from observational studies. In recent years, direct oral anticoagulants (DOACs) have been introduced for thromboprophylaxis. We conducted a systematic literature review to evaluate current practices of anticoagulation in AF, pharmacologic features and adoption patterns of DOACs, their impacts on proportion of eligible patients with AF who receive oral anticoagulants, persisting challenges and future prospects for optimal anticoagulation.

LITERATURE SOURCE AND SELECTION CRITERIA

In conducting this review, we considered the results of relevant prospective and retrospective observational studies from real-world practice settings. PubMed (MEDLINE), Scopus (RIS), Google Scholar, EMBASE and Web of Science were used to source relevant literature. There were no date limitations, while language was limited to English. Selection was limited to articles from peer reviewed journals and related to our topic.

RESULTS

Most studies identified in this review indicated suboptimal use of anticoagulants is a persisting challenge despite the availability of DOACs. Underuse of oral anticoagulants is apparent particularly in patients with a high risk of stroke. DOAC adoption trends are quite variable, with slow integration into clinical practice reported in most countries; there has been limited impact to date on prescribing practice.

CONCLUSION

Available data from clinical practice suggest that suboptimal oral anticoagulant use in patients with AF and poor compliance with guidelines still remain commonplace despite transition to a new era of anticoagulation featuring DOACs.

Cost-effectiveness of edoxaban versus rivaroxaban for stroke prevention in patients with nonvalvular atrial fibrillation (NVAF) in the US

BACKGROUND

Understanding the value of new anticoagulation therapies compared with existing therapies is of paramount importance in today's cost-conscious and efficiency-driven health care environment. Edoxaban and rivaroxaban for stroke prevention in nonvalvular atrial fibrillation (NVAF) patients with CHADS2 scores ≥2 have been evaluated in pivotal trials versus warfarin. The relative value of edoxaban versus rivaroxaban would be of interest to health care stakeholders and patients who prefer a once-daily treatment option for long-term stroke prevention in NVAF.

OBJECTIVE

To evaluate the relative cost-effectiveness of two once-daily regimens of novel oral anticoagulation therapy - edoxaban (60 mg/30 mg dose-reduced) versus rivaroxaban (20 mg/15 mg dose-reduced) - for stroke prevention in NVAF patients from a US health-plan perspective.

MATERIALS AND METHODS

A Markov model simulated lifetime risk and treatment of stroke, systemic embolism, major bleeding, clinically relevant nonmajor bleeding, myocardial infarction, and death in NVAF patients treated with edoxaban or rivaroxaban. Efficacy and safety data were derived from a network meta-analysis that utilized data from patients enrolled in ENGAGE AF-TIMI 48 and ROCKET-AF. Health care cost and utility data were obtained from published sources. Incremental cost-effectiveness ratios of $150,000 per quality-adjusted life year (QALY) gained were used as thresholds for "highly cost-effective", "cost-effective", and "not cost-effective" treatment options, respectively, as per American Heart Association/American College of Cardiology guidelines.

RESULTS

Edoxaban was dominant relative to rivaroxaban, such that it was associated with lower total health care costs and better effectiveness in terms of QALYs in the base-case analysis. Results were supported by probabilistic sensitivity analyses that showed edoxaban as either dominant or a highly cost-effective alternative (incremental cost-effectiveness ratio <$50,000) to rivaroxaban in 88.4% of 10,000 simulations.

CONCLUSION

Results of this study showed that the once-daily edoxaban (60 mg/30 mg dose-reduced) regimen is a cost-saving or highly cost-effective treatment relative to rivaroxaban (20 mg/15 mg dose-reduced) for stroke prevention in NVAF patients with CHADS2 ≥2.

Safety and efficacy of oral factor-Xa inhibitors versus Vitamin K antagonist in patients with non-valvular atrial fibrillation: Meta-analysis of phase II and III randomized controlled trials

BACKGROUND

Aim of our study was to assess the safety and efficacy on factor-Xa inhibitors (FXIs) in patients with non-valvular atrial fibrillation (NVAF) as compared to Vitamin K antagonist (VKA).

METHODS

Phase II and III randomized controlled trials that reported clinical safety and efficacy of FXI in patients with NVAF were identified from MEDLINE, Embase, and Cochrane Central Register of Controlled Trials through December 10, 2015. The primary safety outcome of our study was composite of stroke and systemic embolic event. Secondary outcomes studied were individual endpoints of primary safety outcome, major bleeding, clinically relevant non-major bleed (CRNMB), and all-cause mortality.

RESULTS

We included 11 RCTs with a total of 59,164 participants, of which 34,231 patients received oral FXI and 24,933 patients were on VKA with a mean follow-up of 369days. There was a significant reduction in primary outcome with FXI compared to VKA, 1,112 (3.4%) versus 816 (3.6%) events, respectively (OR 0.82; 95% CI 0.68-0.99). Use of FXI significantly reduced major bleeding events compared to VKA, OR 0.74, 95% CI 0.58-0.96, test for heterogeneity (I(2)=74%). Incidence of CRNMB was not different between FXI and VKA groups, OR 0.84, 95% CI 0.68-1.04. There was a significant reduction in all-cause mortality in FXI group compared to VKA group, OR 0.88, 95% CI 0.83-0.94 with no significant heterogeneity.

CONCLUSION

Use of FXI was associated with a significant reduction in major bleeding events and all-cause mortality without increased risk of stroke or SEE compared to VKA.

Apixaban versus edoxaban for stroke prevention in nonvalvular atrial fibrillation

Oral anticoagulation therapy is the mainstay of stroke prevention in nonvalvular atrial fibrillation patients. Vitamin K antagonists (such as warfarin) have been effective conventional oral anticoagulants for several decades. However, due to their limitations in clinical use, several nonvitamin K antagonist oral anticoagulants (NOACs, including dabigatran, rivaroxaban, apixaban and edoxaban) have been developed. Nonetheless, no head to head trials have been performed to directly compare these NOACs in patient cohorts. In this review article, two direct factor Xa inhibitors, apixaban and edoxaban, are briefly described with focus on their pharmacokinetic and pharmacodynamic profiles, plus drug interactions. Moreover, both efficacy and safety will be discussed based on the available data from the large Phase III clinical trials and indirect comparison studies.

Intracranial bleedings in patients on long-term anticoagulant treatment: Benefits from oral thrombin and factor Xa inhibitors in clinical practice

Dabigatran, a direct thrombin inhibitor and activated factor X inhibitors, rivaroxaban and apixaban, used in the prevention of stroke or systemic embolism in patients with nonvalvular atrial fibrillation (AF), have several advantages over vitamin K antagonists (VKAs). The non-vitamin K oral anticoagulants (NOACs) have been shown to reduce the risk of intracranial bleedings by 50%. The current review summarizes the available data on the epidemiology, mechanisms and treatment of intracranial bleedings observed on oral anticoagulation with the focus on the specificity of NOACs in this context.