Focused 2012 Update of the Canadian Cardiovascular Society Atrial Fibrillation Guidelines: Recommendations for Stroke Prevention and Rate/Rhythm Control

The use of dronedarone for recurrent ventricular tachycardia: a case report and review of the literature

Background

Dronedarone is a benzofuran derivative resembling amiodarone that was intended to reduce the iodine-associated tissue deposition and organ toxicity seen with the latter. The utility of dronedarone for patients with ventricular arrhythmias has not been thoroughly evaluated. We present our experience with its use to treat refractory ventricular tachycardia storm and review the literature.

Case presentation

An 85 year-old gentleman with multiple medical comorbidities including ischemic and non-ischemic cardiomyopathy with severe biventricular systolic dysfunction presented with ventricular tachycardia storm. Therapeutic options were limited given his frail medical status, failures of sotalol, mexilitine, and catheter ablation therapies along with drug-toxicities from amiodarone. Dronedarone was thus considered as off-label use following informed consent. The patient unfortunately developed fatal multisystem organ failure including acute severe hepatotoxicity from dronedarone.

Conclusion

Novel therapies for drug-refractory ventricular arrhythmias are long overdue given the limitations of available pharmacologic and non-pharmacologic options. Off-label use of antiarrhythmic agents such as dronedarone is considered a treatment of last-resort in patients who otherwise have no therapeutic options. Given the paucity of reported cases regarding dronedarone for the treatment of ventricular tachyarrhythmias, no conclusive recommendations can be made at this time aside from words of caution. Despite the potential ventricular antiarrhythmic effects of dronedarone, careful patient evaluation is required to identify those at greatest risk of drug-related adverse events particularly in those patients with significant comorbidities such as advanced hepatic, renal, and cardiovascular disease.

The HAS-BLED Score for Predicting Major Bleeding Risk in Anticoagulated Patients With Atrial Fibrillation: A Systematic Review and Meta-analysis

Our objective was to compare the diagnostic accuracy between the HAS-BLED score and any of HEMORR2 HAGES, ATRIA, CHADS2 , or CHA2 DS2 -VASc scores in anticoagulated patients with atrial fibrillation. We systematically searched the Cochrane Library, MEDLINE, PubMed, and Embase databases for relevant studies. Data were extracted and analyzed according to predefined clinical endpoints. Eleven studies were identified. Discrimination analysis demonstrates that HAS-BLED has no significant C-statistic differences for bleeding risk prediction compared with ATRIA or HEMORR2 HAGES, but it has significant differences compared with CHADS2 or CHA2 DS2 -VASc. The significant positive net reclassification improvement and integrated discrimination improvement values also show that HAS-BLED is superior to that of any of HEMORR2 HAGES, ATRIA, CHADS2 , or CHA2 DS2 -VASc scores. According to calibration analysis of HAS-BLED, it overpredicts the risk of bleeding in the low (risk ratio [RR]: 1.16, 95% confidence interval [CI]: 0.63-2.13, P = 0.64) risk stratification but underpredicts that in the moderate (RR: 0.66, 95% CI: 0.51-0.86, P = 0.002) and high (RR: 0.88, 95% CI: 0.70-1.10, P = 0.27) risk stratifications. The HAS-BLED score not only performs better than the HEMORR2 HAGES and ATRIA bleeding scores, but it also is superior to the CHADS2 and CHA2 DS2 -VASc stroke scores for bleeding prediction. The HAS-BLED score should be the optimal choice to assess major bleeding risk in clinical practice.

[Use of the CHADS2 score as a predictor of the risk of mortality in hypertensive patients. The FAPRES study]

FOUNDATIONS AND AIM

The aim of this study is to analyze the CHADS2 score as a marker of the risk of mortality in hypertensive patients, with and without the presence of atrial fibrillation.

METHODS

We included 1,003 hypertensive patients≥65 years. Risk factors, and CHADS2 score were recorded among other factors, as well as clinical follow-up of number and type of deaths.

RESULTS

Mean age was 72.8±5.8 years, and 47.5% were men. During follow-up there were 41 deaths, 20 were of cardiovascular origin. Patients with higher CHADS2 had a higher mortality: 1.5% CHADS2=1; 4.7% in CHADS2=2; 9.1% in CHADS2=3, and 7.8% in CHADS2≥4.

CONCLUSIONS

The CHADS2 score can be a clinical instrument of easy application to identify hypertensive patients with a high risk of mortality.

Dronedarone: Basic Pharmacology and Clinical Use

Dronedarone is the newest antiarrhythmic drug approved for the maintenance of sinus rhythm in patients with nonpermanent atrial fibrillation (AF). It is a multi-channel blocker with diverse electrophysiologic properties. Dronedarone decreases the incidence of AF recurrence and the ventricular rate during recurrence. Dronedarone decreases rates of cardiovascular hospitalizations in patients with paroxysmal and persistent AF. Dronedarone increases mortality in patients with permanent AF and those with moderate-severe heart failure, and should thus be avoided in these populations. Dronedarone is less effective than amiodarone but also has less toxicity. Direct comparison with other antiarrhythmic drugs is not available.

The Mechanism of and Preventive Therapy for Stroke in Patients with Atrial Fibrillation

Atrial fibrillation is a major cardiac cause of stroke, and a pathogenesis involving thrombus formation in patients with atrial fibrillation is well established. A strategy for rhythm control that involves catheter ablation and anticoagulation therapy is evolving. A strategy for rhythm control that restores and maintains sinus rhythm should reduce the risk of ischemic stroke that is associated with atrial fibrillation; however, this is yet to be proven in large-scale randomized controlled trials. This paper reviews the emerging role of rhythm control therapy for atrial fibrillation to prevent stroke.

Predictive ability of HAS-BLED, HEMORR2HAGES, and ATRIA bleeding risk scores in patients with atrial fibrillation. A French nationwide cross-sectional study

OBJECTIVE

The HAS-BLED, ATRIA, and HEMORR2HAGES risk scores were created to evaluate individual bleeding risk in atrial fibrillation (AF). We sought to estimate and compare the predictive ability of these scores for major hemorrhage in AF, including elderly (≥80years) and non-elderly (<80years) patients.

METHODS

This cross-sectional study is based on the French National Hospital Database (PMSI), which covers the entire French population. Data from all patients with an AF diagnosis in 2012 were extracted. Demographic and comorbidity data were used to calculate the three bleeding risk scores for each patient. Patients hospitalized with a principal diagnosis of major bleeding were identified.

RESULTS

Of the 533,044 AF patients identified, 53.2% were ≥80years; 7013 patients (1.3%) were hospitalized for a bleeding event (1785 for intracranial hemorrhage). Bleeding occurred more frequently in patients with higher HAS-BLED, HEMORR2HAGES, and ATRIA scores. In patients ≥80years, the c-statistics did not differ (p=0.27) between HAS-BLED (0.54; 95% confidence interval [CI]: 0.53-0.54), HEMORR2HAGES (0.53; 95% CI: 0.53-0.54), and ATRIA (0.53; 95% CI: 0.52-0.54). In patients <80years, HAS-BLED (0.59; 95% CI: 0.58-0.60) had a slightly higher c-statistic than HEMORR2HAGES (0.56; 95% CI: 0.55-0.57) and ATRIA (0.55, 95% CI: 0.55-0.56) (p<0.0001).

CONCLUSIONS

Given its simplicity and similar performance, HAS-BLED may be an attractive alternative to HEMORR2HAGES for estimation of bleeding risk in AF patients <80years. However, accurate determination of bleeding risk among the elderly is difficult with existing risk-prediction scores, indicating a clear need for improvement in their clinical utility.

Safety of non-vitamin K antagonist oral anticoagulants - coronary risks

INTRODUCTION

Since the approval and commercialization of non-vitamin K antagonist oral anticoagulants (NOACs; apixaban, dabigatran, edoxaban, and rivaroxaban) several studies and meta-analyses have raised safety concerns regarding myocardial infarction (MI) risk among NOAC-treated patients, particularly with dabigatran. Uncertainty remains regarding the coronary risk associated with dabigatran, and whether this putative risk also applies to the other NOACs.

AREAS COVERED

In this review, the coronary risks of NOACs based on findings from placebo-controlled trials are discussed, and randomized controlled trials and major cohort studies in AF patients are also appraised. We performed a random-effect meta-analysis, including both interventional trials and observational studies ("real-world" data). Further estimates were retrieved from the meta-analysis of coronary risk among NOAC-treated patients with concomitant AF and coronary disease.

EXPERT OPINION

Currently, the best available data from both clinical trials and observational studies do not support the claim that patients treated with NOACs, including dabigatran, are at increased coronary risk. However, a definitive conclusion cannot be made (especially regarding dabigatran) and further data are required to address the coronary risks, mostly of high-risk patients. As with any therapeutic intervention, the possible complications should be balanced against the potential benefits at an individual patient level.

Appropriate Use of Antithrombotic Medication in Canadian Patients With Nonvalvular Atrial Fibrillation

This national chart audit of 7,019 patients with nonvalvular atrial fibrillation (AF) from 735 primary care physician practices sought to examine the management of Canadian patients with AF through an evidence-based, guideline-recommended approach. The appropriate use of oral anticoagulants (OACs) in this patient population and the potential factors guiding OAC choice were examined. Suboptimal dosing was seen. In patients on warfarin, 30.9% had not achieved a time in therapeutic range (TTR) in excess of 65% and, despite current Canadian guideline recommendations, were continued on warfarin rather than one of the novel OACs. In patients who received no antithrombotic therapy, 65.5% met criteria for treatment with an OAC. In addition, 62.8% of patients who were treated with acetylsalicylic acid monotherapy met guideline criteria for the use of an OAC. In those patients treated with an OAC, 24.8% were not on the recommended dose based on the product monograph or, if on warfarin, had a TTR <65%. Of the patients on novel OACs (NOACs), 7.4% of patients were underdosed, whereas overdosing was seen in 4.3%. Factors that may have contributed to dosing outside recommendations included underestimation of stroke risk, overestimation of bleed risk, compliance concerns, and lack of provincial reimbursement. In conclusion, significant correctable gaps remain in optimal treatment for stroke prevention in AF.

Temporal Patterns and Predictors of Rate vs Rhythm Control in Patients Attending a Multidisciplinary Atrial Fibrillation Clinic

BACKGROUND

Contemporary trends in the selection of and persistence with rate vs rhythm control for atrial fibrillation (AF) are not well studied, particularly in the context of multidisciplinary AF clinics.

METHODS

The initial arrhythmia management strategy in 1031 consecutive patients attending a multidisciplinary AF clinic from 2005-2012 was analyzed.

RESULTS

The 397 (38.5%) patients initially treated with rhythm control were younger (57.4 ± 14 years vs 65.6 ± 13 years; P < 0.0001) and more likely to be men (64.5% vs 56.9%; P = 0.019). They also had fewer comorbidities, lower CHADS₂ (Congestive Heart Failure, Hypertension, Age, Diabetes, Stroke/Transient Ischemic Attack) scores, and greater symptom burden. The proportion treated with rhythm control declined from 46.9% in 2005-2006 to 28.4% in 2012 (P for trend < 0.0001). Compared with those initially selecting rate control, patients treated with rhythm control required more frequent clinic encounters (7 [interquartile range {IQR}, 3-12] vs 3 [IQR, 2-7]; P < 0.001) and longer follow-up (266 days [IQR, 84-548 days] vs 99 days [IQR, 0-313 days]; P < 0.001). Younger age, absence of diabetes and sleep apnea, earlier treatment year, higher symptom burden, and rural residence were independently associated with rhythm control. Persistence with the initial treatment strategy was reduced in the rhythm-control group (P = 0.003).

CONCLUSIONS

Use of rhythm control as the initial arrhythmia management strategy for AF in a specialty AF clinic is declining. Rhythm control requires more intensive follow-up and was more likely to lead to a change in arrhythmia management strategy.

Guidelines for Potassium Channel Blocker Use

This article summarizes recommendations for the clinical use of antiarrhythmic drugs for the treatment and prevention of atrial and ventricular arrhythmias based on current guideline and consensus documents. The choice of antiarrhythmic drug is based on the efficacy and safety profile and influenced by the presence or absence of structural heart disease. Because of its adverse side-effect profile, amiodarone is recommended for the management of atrial fibrillation only when other agents have failed or are contraindicated. For treatment of symptomatic ventricular arrhythmias in the setting of structural heart disease, amiodarone is generally the preferred agent.

Strategy of continued vs interrupted novel oral anticoagulant at time of device surgery in patients with moderate to high risk of arterial thromboembolic events: The BRUISE CONTROL-2 trial

BACKGROUND

Patients who require perioperative anticoagulation during cardiac implantable electronic device surgery are at increased risk for bleeding complications. The BRUISE CONTROL trial demonstrated that continuing warfarin was safer than heparin bridging, reducing the incidence of clinically significant pocket hematoma. Novel oral anticoagulants are being increasingly prescribed in place of warfarin. The best perioperative management of these new anticoagulants is unknown.

METHODS/DESIGN

A randomized controlled trial to investigate whether a strategy of continued vs interrupted novel oral anticoagulant (dabigatran, rivaroxaban, or apixaban) at the time of device surgery, in patients with moderate to high risk of arterial thromboembolic events, reduces the incidence of clinically significant hematoma (defined as a hematoma requiring reoperation and/or resulting in prolongation of hospitalization, and/or requiring interruption of anticoagulation). The secondary outcomes include components of the primary outcome, composite of all other major perioperative bleeding events, thromboembolic events, all-cause mortality, cost-effectiveness, patient quality of life, perioperative pain, and satisfaction. Planned analyses include descriptive statistics of all baseline variables. For the primary outcome, interrupted vs continued novel oral anticoagulant arms will be compared using the χ(2) test. If any clinically significant differences are identified, a logistic regression analysis will be conducted. Quality of life will be assessed using EuroQol-5D, and perioperative pain using a visual analog scale.

DISCUSSION

BRUISE CONTROL-2 is a randomized trial evaluating the best strategy to manage novel oral anticoagulants at the time of device surgery. We hypothesize that device surgery can be performed safely without interruption of these medications.

Evaluating the Usability and Perceived Impact of an Electronic Medical Record Toolkit for Atrial Fibrillation Management in Primary Care: A Mixed-Methods Study Incorporating Human Factors Design

BACKGROUND

Atrial fibrillation (AF) is a common and preventable cause of stroke. Barriers to reducing stroke risk through appropriate prescribing have been identified at the system, provider, and patient levels. To ensure a multifaceted initiative to address these barriers is effective, it is essential to incorporate user-centered design to ensure all intervention components are optimized for users.

OBJECTIVE

To test the usability of an electronic medical record (EMR) toolkit for AF in primary care with the goal of further refining the intervention to meet the needs of primary care clinicians.

METHODS

An EMR-based toolkit for AF was created and optimized through usability testing and iterative redesign incorporating a human factors approach. A mixed-methods pilot study consisting of observations, semi-structured interviews, and surveys was conducted to examine usability and perceived impact on patient care and workflow.

RESULTS

A total of 14 clinicians (13 family physicians and 1 nurse practitioner) participated in the study. Nine iterations of the toolkit were created in response to feedback from clinicians and the research team; interface-related changes were made, additional AF-related resources were added, and functionality issues were fixed to make the toolkit more effective. After improvements were made, clinicians expressed that the toolkit improved accessibility to AF-related information and resources, served as a reminder for guideline-concordant AF management, and was easy to use. Most clinicians intended to continue using the toolkit for patient care. With respect to impact on care, clinicians believed the toolkit increased the thoroughness of their assessments for patients with AF and improved the quality of AF-related care received by their patients.

CONCLUSIONS

The positive feedback surrounding the EMR toolkit for AF and its perceived impact on patient care can be attributed to the adoption of a user-centered design that merged clinically important information about AF management with user needs. This study demonstrates the utility of a human factors approach to piloting and refining an intervention prior to wide-scale implementation.

How to choose appropriate direct oral anticoagulant for patient with nonvalvular atrial fibrillation

The novel oral anticoagulants or direct oral anticoagulants (DOAC) are becoming more common in clinical practice for the prevention of stroke in non-valvular atrial fibrillation (NVAF). The availability of several agents with similar efficacy and safety for stroke prevention in NVAF patients offers more selection, but at the same time requires certain knowledge to make a good choice. This comparative analysis provides an appraisal of the respective clinical trials and highlights much of what remains unknown about four FDA-approved agents: dabigatran, apixaban, rivaroxaban, and edoxaban. It details how the DOACs compare to warfarin and to one another summarizes pharmacologic and pharmacodynamic properties, and drug interactions from the stand point of practical consequences of these findings. Common misconceptions and reservations are addressed. The practical application of this data is intended to help choosing the most appropriate agent for individual NVAF patient.

Use of Warfarin at Discharge Among Acute Ischemic Stroke Patients With Nonvalvular Atrial Fibrillation in China

Background and Purpose—

Guidelines recommend oral anticoagulation for ischemic stroke patients with atrial fibrillation, and previous studies have shown the underuse of anticoagulation for these patients in China. We sought to explore the underlying reasons and factors that currently affect the use of warfarin in China.

Methods—

From June 2012 to January 2013, 19 604 patients with acute ischemic stroke were admitted to 219 urban hospitals voluntarily participating in the China National Stroke Registry II. Multivariable logistic regression models using the generalized estimating equation method were used to identify patient/hospital factors independently associated with warfarin use at discharge.

Results—

Among the 952 acute ischemic stroke patients with nonvalvular atrial fibrillation, 19.4% were discharged on warfarin. The risk of bleeding (52.8%) and patient refusal (31.9%) were the main reasons for not prescribing anticoagulation. Larger/teaching hospitals were more likely to prescribe warfarin. Older patients, heavy drinkers, patients with higher National Institutes of Health Stroke Scale score on admission were less likely to be given warfarin, whereas patients with history of heart failure and an international normalized ratio between 2.0 and 3.0 during hospitalization were significantly associated with warfarin use at discharge.

Conclusions—

The rate of warfarin use remains low among patients with ischemic stroke and known nonvalvular atrial fibrillation in China. Hospital size and academic status together with patient age, heart failure, heavy alcohol drinking, international normalized ratio in hospital, and stroke severity on admission were each independently associated with the use of warfarin at discharge. There is much room for improvement for secondary stroke prevention in nonvalvular atrial fibrillation patients in China.

Assessment of the Quality of Chronic Anticoagulation Control With Time in Therapeutic Range in Atrial Fibrillation Patients Treated With Vitamin K Antagonists by Hemostasis Specialists: The TERRA Registry: Tiempo en rango en la República Argentina

BACKGROUND

Oral anticoagulation therapy with vitamin K antagonists (VKA) such as warfarin and acenocoumarol is recommended in patients with atrial fibrillation (AF) and risk factors for embolism. The quality of anticoagulation control with VKA may be assessed by the time in therapeutic range (TTR). In our country, there are no data available about the quality of anticoagulation in patients with AF. The primary goal of our study was to assess the level of effective anticoagulation in a multicenter network of anticoagulation clinics in Argentina, which included patients with nonvalvular AF (NVAF) treated with VKA oral anticoagulants.

METHODS

The TERRA trial is a multicenter, cross-sectional study involving 14 anticoagulation clinics that were invited to participate and recruit 100 consecutive patients with NVAF treated with VKA for more than 1 year. The international normalized ratio (INR) values were retrospectively obtained from patient charts, and TTR was calculated using the Rosendaal method.

RESULTS

A total of 1190 patients were included in the analysis. Mean age was 74.9 ± 9.9 years, and 52.5% of the patients were male. Median TTR was 67.5% (interquartile interval 54-80). During 55% of the TTR, INR was >3. Interinstitution variability was substantial, with a range of 57.7% ± 17% to 87.7% ± 17%, P < .001. The 10th percentile of TTR was 41%, the 20th percentile was 50%, the 30th was 58%, and the 35th percentile was 60%. In 40% of patients, TTR was <70%.

CONCLUSION

In this multicenter study, mean TTR values in patients with AF under VKA were similar to those in international therapeutic clinical trials (55%-65%). Marked variations among institutions were observed and, although average results obtained were high, one third of the patients exhibited a TTR below 60%. This cutoff value is conservative according to current recommendations, and guidelines suggest that when management with VKA cannot be improved, patients should be switched to direct oral anticoagulants. The addition of TTR calculation to clinical practice may help improve the quality of oral anticoagulation in patients with AF, thus improving anticoagulation outcomes.

The 2014 Atrial Fibrillation Guidelines Companion: A Practical Approach to the Use of the Canadian Cardiovascular Society Guidelines

The Canadian Cardiovascular Society (CCS) Atrial Fibrillation Guidelines Program has generated a comprehensive series of documents regarding the management of atrial fibrillation (AF) between 2010 and 2014. The guidelines provide evidence-based consensus management recommendations in a broad range of areas. These guidelines have proven useful in informing clinical practice, but often lack detail in specifications related to practical application, particularly for areas in which the evidence base is limited or conflicting. Based on feedback from the community, the CCS Atrial Fibrillation Guidelines Committee has identified a number of areas that require clarification to address commonly asked practical questions related to guidelines application. In the present article a number of such questions are presented and suggestions about how they can be answered are suggested. Among the issues considered are: (1) What duration of AF is clinically significant? (2) How are the risk factors in the CCS Algorithm for selecting anticoagulation therapy derived and defined? (3) How is valvular heart disease defined and how do different forms of valve disease affect the choice of anticoagulant therapy for AF patients? (4) How should we quantify renal dysfunction and how does it affect therapeutic choices? The response to these questions and the underlying logic are provided, along with an indication of future research needed where no specific approach can presently be recommended based on the literature.

Efficacy and safety of apixaban compared with aspirin in the elderly: a subgroup analysis from the AVERROES trial

BACKGROUND

increasing age is associated with a higher prevalence of atrial fibrillation (AF), and higher risks of stroke and bleeding. We report the effects of apixaban versus acetylsalicylic acid (ASA) in older patients (≥75 years and ≥85 years) compared with younger patients with AF unsuitable for vitamin K antagonists.

METHODS

AVERROES (Apixaban Versus ASA to Prevent Stroke In AF Patients Who Have Failed or Are Unsuitable for Vitamin K Antagonist Treatment) trial (n = 5,599) included 1,898 patients ≥75 years and 366 patients ≥85 years. We compared the baseline characteristics and effects of apixaban compared with aspirin on clinical outcomes by age.

RESULTS

compared with aspirin, apixaban was more efficacious for preventing strokes and systemic embolism in patients ≥85 years (absolute rate [AR] 1%/year on apixaban versus 7.5%/year on aspirin; hazard ratio [HR] 0.14, 95% confidence interval [CI] 0.02-0.48) compared with younger patients (AR 1.7%/year on apixaban versus 3.4%/year on aspirin; HR 0.50, 95% CI 0.35-0.69) (P-value for interaction = 0.05). Major haemorrhage was higher in patients ≥85 years compared with younger patients but similar with apixaban versus aspirin in both young and older individuals (4.9%/year versus 1.0%/year on aspirin and 4.7%/year versus 1.2%/year on apixaban) with no significant treatment-by-age interaction (P-value = 0.65).

CONCLUSIONS

older patients with AF are at particularly high risk of stroke if given aspirin and have substantially greater relative and absolute benefits from apixaban compared with younger patients with no greater risk of haemorrhage.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov number: NCT00496769. URL: https://clinicaltrials.gov/ct2/show/NCT00496769.

[Treatment safety of non-vitamin K oral anticoagulants in patients with atrial fibrillation]

Non-vitamin K oral anticoagulants (NOAC) have now become established for stroke prevention in atrial fibrillation. The efficacy is at least as good if not better than that of vitamin K antagonists (VKA). The risk for major bleeding is less for NOAC than for VKA, with a particular superiority concerning the avoidance of intracerebral hemorrhage. The outcome after major bleeding is more favorable in patients receiving NOAC compared to those treated with VKA. Specific reversal agents for NOAC are currently being tested which neutralize the effects of NOAC within minutes and the clinical introduction of the first one for the thrombin inhibitor dabigatran is imminent. Such specific antidotes will further improve the safety profile of NAOC.

How to choose appropriate direct oral anticoagulant for patient with nonvalvular atrial fibrillation

The novel oral anticoagulants or direct oral anticoagulants (DOAC) are becoming more common in clinical practice for the prevention of stroke in non-valvular atrial fibrillation (NVAF). The availability of several agents with similar efficacy and safety for stroke prevention in NVAF patients offers more selection, but at the same time requires certain knowledge to make a good choice. This comparative analysis provides an appraisal of the respective clinical trials and highlights much of what remains unknown about four FDA-approved agents: dabigatran, apixaban, rivaroxaban, and edoxaban. It details how the DOACs compare to warfarin and to one another summarizes pharmacologic and pharmacodynamic properties, and drug interactions from the stand point of practical consequences of these findings. Common misconceptions and reservations are addressed. The practical application of this data is intended to help choosing the most appropriate agent for individual NVAF patient.

Contemporary measures to reduce the risk of embolic events in patients with atrial fibrillation

Atrial fibrillation is a common arrhythmia with significant risk of embolic events. Patients with atrial fibrillation should undergo a careful assessment using validated risk score calculators to estimate the risk of embolic events and the risk of bleeding. Patients deemed to be at a high risk for arterial thromboembolism should be advised to take an oral anticoagulant with a vitamin K antagonist or a target-specific oral anticoagulant unless contraindicated. These agents significantly reduce the risk of embolic events, but at the expense of a higher risk of bleeding. Antiplatelet agents do not confer the same degree of protection and their use should limited. When antithrombotic treatment is contraindicated, novel approaches such as left atrial appendage occlusion should be considered.

Clinical utility of dabigatran in United Arab Emirates. A pharmacovigilance study

Objectives:

To provide early data regarding clinical utility of dabigatran in Al-Ain, United Arab Emirates (UAE).

Methods:

This was an ethics approved retrospective cross sectional study. We retrieved a total of 76 patients who were using dabigatran from September to December 2014 in the Cardiology Clinic at Al-Ain Hospital, Al-Ain, UAE. The primary analysis was designed to test the frequency of bleeding events (rate) with dabigatran 75, 110, and 150 mg.

Results:

The mean age ± standard deviation of cohort was 67.9 ± 1.5 years (range; 29-98 years), composed of males (52.6%) with mean age of 66.3 ± 1.7 years, and females (47.4%) with mean age of 69.6 ± 1.1 years. The highest age group was those between 61-80 years (60.5%). Most comprised the age strata of ≤75 years (73.7%). The main indication for dabigatran use was atrial fibrillation. The rate of bleeding with dabigatran was 18/76 (23.7%), and melena was the leading cause of bleeding 8/76 (10.7%). The hospitalization rate was 67.1%, dabigatran withdrawal rate was 0.01%, and mortality rate was 6.5%. The cohort had exhibited incidences of minor bleeding with one fatal major bleeding, high co-morbidities, admission, and readmission, which was not directly linked to dabigatran. We did not identify any relation of death due to dabigatran.

Conclusion:

Dabigatran is a suitable alternative to warfarin obviating the need for repetitive international normalized ratio monitoring, however, it may need plasma drug monitoring.

Long-term stroke rates after catheter ablation or antiarrhythmic drug therapy for atrial fibrillation: a meta-analysis of randomized trials

BACKGROUND

Atrial fibrillation (AF) is an independent risk factor for ischemic stroke and is associated with increased risk of death. Randomized studies suggest improved quality of life for patients with AF after successful catheter ablation compared to antiarrhythmic drug therapy. The value of ablation in long-term risk of ischemic stroke, however, has not been assessed. We conducted a meta-analysis to determine whether AF ablation reduces the long-term risk of stroke compared to antiarrhythmic drug therapy in randomized controlled trials.

METHODS & RESULTS

PubMed and the Cochrane Central Register were searched for randomized trials from January 1990 to December 2014 comparing AF catheter ablation to drug therapy. The results are reported as risk differences (RDs) and 95% CI. Thirteen trials were analyzed with 1097 patients treated by catheter ablation and 855 patients received antiarrhythmic drug therapy. Overall, seven patients (0.64%) in the catheter ablation group had ischemic stroke or transient ischemic attacks vs. two patients (0.23%) in the drug therapy group. No difference was shown in the rate of stroke or transient ischemic attack between ablation and drug therapy (RD: 0.003, 95% CI: -0.006 to 0.012, P = 0.470), and no evidence of heterogeneity was observed (I (2) = 0, P = 0.981). No potential publication bias was found. There was also no difference in mortality between the two groups (RD: -0.004, 95% CI: -0.014 to 0.006, P = 0.472).

CONCLUSIONS

This meta-analysis of randomized controlled trials showed similar rates of ischemic stroke or transient ischemic attack and death in AF patients undergoing catheter ablation compared to drug therapy. A larger prospective randomized trial to confirm this finding is warranted.

Cardiovascular causes of emergency neurology presenting to an ICU

Stroke or transient ischemic attacks (TIA) represent an urgent clinical entity that is not limited only to elderly patients. The underlying causes of stroke and TIA are diverse, with those of cardiovascular origin being among the most prominent. This review seeks to elucidate some of the most important aspects of the disease in the context of emergency and critical care practice.

Impact of Rural Residence on Warfarin Use and Clinical Events in Patients with Non-Valvular Atrial Fibrillation: A Canadian Population Based Study

BACKGROUND AND PURPOSE

We studied whether anticoagulant use and outcomes differed between rural versus urban Canadian non-valvular atrial fibrillation (NVAF) patients prior to the introduction of direct oral anticoagulant drugs.

METHODS

Retrospective cohort study of 25,284 adult Albertans with NVAF between April 1, 1999 and December 31, 2008.

RESULTS

Compared to urban patients, rural patients were older (p = 0.0009) and had more comorbidities but lower bleeding risk at baseline. In the first year after NVAF diagnosis, urban patients were less likely to be hospitalized (aOR 0.82, 95%CI 0.77-0.89) or have an emergency department visit for any reason (aOR 0.61, 95%CI 0.56-0.66) but warfarin dispensation rates (72.2% vs 71.8% at 365 days, p = 0.98) and clinical outcomes were similar: 7.8% died in both groups, 3.2% rural vs. 2.8% urban had a stroke or systemic embolism (SSE) (aOR 0.92, 95%CI 0.77-1.11), and 6.6% vs. 5.7% (aOR 0.93, 95%CI 0.81-1.06) had a bleed. Baseline SSE risk did not impact warfarin dispensation (73.0% in those with high vs. 72.8% in those with low CHADS2 score, p = 0.85) but patients at higher baseline bleeding risk were less likely to be using warfarin (69.2% high vs. 73.6% low HASBLED score, p<0.0001) in the first 365 days after diagnosis. In warfarin users, bleeding was more frequent (7.5% vs 6.2%, aHR 1.51 [95%CI 1.33-1.72]) but death or SSE was less frequent (7.0% vs 18.1%, aHR 0.60 [0.54-0.66]).

CONCLUSION

Warfarin use and clinical event rates did not differ between rural and urban NVAF patients in a universal access publically-funded healthcare system.

Paroxysmal atrial fibrillation and the hazards of under-treatment

BACKGROUND AND PURPOSE

Oral anticoagulants are highly efficacious for the prevention of stroke in atrial fibrillation, and are the preferred treatment by current guidelines. The purpose of our study was to assess the utilization of antithrombotic drugs in atrial fibrillation patients at the time of ischemic stroke and the factors associated with their use.

METHODS

We enrolled 759 consecutive patients admitted with ischemic stroke at Boston Medical Center, Geisinger Health System, and the University of Alabama. To be eligible, patients had to have electrocardiographically-confirmed atrial fibrillation at the time of admission or within 6 months of the index stroke. All stroke events and electrocardiograms were validated by study physicians. Patients with newly diagnosed atrial fibrillation were not eligible.

RESULTS

The mean age was 78 years, 43% were male, 19% black, and the mean CHADS2 score is 3.0. Atrial fibrillation was paroxysmal in 31%. At presentation, 181 (24%) patients were taking warfarin only, 96 (13%) both warfarin and aspirin, 294 (39%) aspirin alone, and 189 (25%) no antithrombotic therapy. The mean international normalized ratio was 1.6. Among patients with paroxysmal atrial fibrillation, one in five was taking warfarin. Although increasing stroke risk was associated with a greater likelihood of warfarin use, only 39% of highest risk CHADS2 3-6 were taking warfarin at the time of stroke.

CONCLUSIONS

Among high-risk individuals with atrial fibrillation, only 37% were taking warfarin at the time of stroke. Paroxysmal atrial fibrillation was associated with the highest risk of not receiving warfarin.

Dabigatran use in elderly patients with atrial fibrillation

In elderly patients (≥ 75 years), evidence of dabigatran efficacy is lacking and increased vigilance is warranted. We aimed to assess dabigatran effectiveness and safety in elderly patients in real-world practice. We conducted a population-based study using administrative databases, in Quebec (1999-2013). Dabigatran users (110/150 mg) were compared with matched warfarin users with regard to stroke and bleeding events. Age was categorised into < 75 or ≥ 75 years. Propensity score adjusted models were used. The cohort consisted of 15,918 dabigatran users and 47,192 matched warfarin users, with 67.3% being elderly patients. The elderly predominantly used the lower dose (80.1%) while younger patients mainly used the higher dose (80.0%). In multivariable analyses adjusted for propensity score, the risk of stroke in elderly patients using dabigatran, was no different than the risk in warfarin users (HR 1.05, 95% CI: 0.93, 1.19) regardless of dabigatran dose. However, dabigatran was associated with lower rates of intracranial haemorrhage (HR 0.60, 95% CI: 0.47-0.76) and higher rates of gastrointestinal bleeding (HR 1.30 95% CI: 1.14-1.50) when compared to warfarin. Based on real-life experience, dabigatran can offer an alternative to warfarin in elderly patients, with fewer intracranial bleeding events. However, caution is warranted for gastrointestinal bleeding.

Dosing of rivaroxaban by indication: getting the right dose for the patient

INTRODUCTION

Vitamin K antagonists were the only oral anticoagulants available for several decades, but they require frequent coagulation monitoring and dose adjustment. The direct oral anticoagulants rivaroxaban , dabigatran, apixaban, and, most recently, edoxaban have been approved for the management of specific thromboembolic indications.

AREAS COVERED

This review will provide a brief overview of the cell-based coagulation model, the main determinants of arterial and venous thrombosis, and the pharmacological rationale and clinical evidence for the different dosing regimens of rivaroxaban. Published articles indexed on PubMed and Medline covering arterial and venous thrombi pathophysiology, pharmacokinetics, and pharmacodynamics of rivaroxaban, and Phase II and Phase III clinical studies with rivaroxaban as well as real-world evidence were analyzed.

EXPERT OPINION

Education on pharmacokinetic/pharmacodynamic characteristics, as well as how to manage adverse events, is needed to increase physician knowledge and confidence in using direct oral anticoagulants, as specifically discussed for rivaroxaban in this article. The continued uptake of direct oral anticoagulants in clinical practice depends on understanding of the clinical evidence and reassurance provided by emerging real-world data.

Initiation of rivaroxaban in patients with nonvalvular atrial fibrillation at the primary care level: the Swiss Therapy in Atrial Fibrillation for the Regulation of Coagulation (STAR) Study

BACKGROUND

Rivaroxaban has become an alternative to vitamin-K antagonists (VKA) for stroke prevention in non-valvular atrial fibrillation (AF) patients due to its favourable risk-benefit profile in the restrictive setting of a large randomized trial. However in the primary care setting, physician's motivation to begin with rivaroxaban, treatment satisfaction and the clinical event rate after the initiation of rivaroxaban are not known.

METHODS

Prospective data collection by 115 primary care physicians in Switzerland on consecutive nonvalvular AF patients with newly established rivaroxaban anticoagulation with 3-month follow-up.

RESULTS

We enrolled 537 patients (73±11years, 57% men) with mean CHADS2 and HAS-BLED-scores of 2.2±1.3 and 2.4±1.1, respectively: 301(56%) were switched from VKA to rivaroxaban (STR-group) and 236(44%) were VKA-naïve (VN-group). Absence of routine coagulation monitoring (68%) and fixed-dose once-daily treatment (58%) were the most frequent criteria for physicians to initiate rivaroxaban. In the STR-group, patient's satisfaction increased from 3.6±1.4 under VKA to 5.5±0.8 points (P<0.001), and overall physician satisfaction from 3.9±1.3 to 5.4±0.9 points (P<0.001) at 3months of rivaroxaban therapy (score from 1 to 6 with higher scores indicating greater satisfaction). In the VN-group, both patient's (5.4±0.9) and physician's satisfaction (5.5±0.7) at follow-up were comparable to the STR-group. During follow-up, 1(0.19%; 95%CI, 0.01-1.03%) ischemic stroke, 2(0.37%; 95%CI, 0.05-1.34%) major non-fatal bleeding and 11(2.05%; 95%CI, 1.03-3.64%) minor bleeding complications occurred. Rivaroxaban was stopped in 30(5.6%) patients, with side effects being the most frequent reason.

CONCLUSION

Initiation of rivaroxaban for patients with nonvalvular AF by primary care physicians was associated with a low clinical event rate and with high overall patient's and physician's satisfaction.

Left atrial appendage closure is preferred to chronic warfarin therapy: the pro perspective

Atrial fibrillation (AF) is associated with increased rates of death, stroke, heart failure, hospitalization, degraded quality of life, reduced exercise capacity, and left ventricular dysfunction. An oral anticoagulant reduces the risk of stroke; however, it places the patient at risk for bleeding complications. Weighing the stroke and bleeding risks remains the key for optimal treatment. Cardiac interventions that can obviate long-term oral anticoagulation hold great promise for the future care of patients with AF and high stroke risk. The percutaneously deployable Watchman device is a paradigm shift in how clinicians can abate the need for continued oral anticoagulation.

Warfarin use and the risks of stroke and bleeding in hemodialysis patients with atrial fibrillation: A systematic review and a meta-analysis

BACKGROUND AND AIM

The efficacy and safety of warfarin therapy in hemodialysis (HD) patients with atrial fibrillation (AF) remains controversial. Thus, we performed, up to date, the first meta-analysis on the risks of stroke and bleeding in warfarin treatment in these populations.

METHODS AND RESULTS

The relevant literature was searched using the following electronic databases without any language restrictions: the Cochrane Library Database, PubMed, ISI, Ovid, and Chinese Biomedical Database from the establishment of the database to October 2014. The studies were included if (a) studies described the risk of stroke or bleeding with or without warfarin in dialysis patients with AF, (b) studies provided information about hazard ratio (HR) and 95% confidence interval (CI) of stroke or bleeding, and (c) the study design was a clinical cohort. The inverse variance method was used to obtain overall HRs and 95% CIs. Sensitivity analyses and publication bias were also performed. We identified six eligible studies with a total of 9816 patients. Combined HRs showed that warfarin cannot prevent strokes in HD patients with AF (HR = 1.23, 95% CI 0.80-1.87; P = 0.347), but its use was associated with a higher risk of bleeding (HR = 1.20, 95% CI 1.03-1.39; P = 0.019).

CONCLUSION

This meta-analysis suggested that warfarin should not be recommended for the routine treatment of HD patients with AF.

Oral anticoagulant therapy in atrial fibrillation patients at high stroke and bleeding risk

Atrial fibrillation (AF) is associated with a 5-fold greater risk of ischemic stroke or systemic embolism compared with normal sinus rhythm. Cardioembolic AF-related strokes are often more severe, fatal or associated with greater permanent disability and higher recurrence rates than strokes of other aetiologies. These strokes may be effectively prevented with oral anticoagulant (OAC) therapy, using either vitamin K antagonists (VKAs) or non-vitamin K antagonist OACs (NOACs) such as the direct thrombin inhibitor dabigatran or direct factor Xa inhibitors rivaroxaban, apixaban or edoxaban. Most AF patients have a positive net clinical benefit from OAC, excluding those with AF and no conventional stroke risk factors. Balancing the risks of stroke and bleeding is necessary for optimal use of OAC in clinical practice, and modifiable bleeding risk factors must be addressed. Concerns remain over 'non-changeable' bleeding risk factors such as older age, significant renal or hepatic impairment, prior stroke(s) or prior bleeding event(s) and active malignancies. Such AF patients are often termed 'special' AF populations, due to their 'special' risk profile that includes increased risks of both thromboembolic and bleeding events, and due to fear of bleeding complications these AF patients are often denied OAC. Evidence shows, however, that the absolute benefits of OAC are the greatest in patients at the highest risk, and NOACs may offer even a greater net clinical benefit compared to warfarin particularly in these high risk patients. In this review article, we summarize available data on stroke prevention in AF patients at increased risk of both stroke and bleeding and discuss the use of NOACs for thromboprophylaxis in these 'special' AF populations.

A Decision Analysis of Percutaneous Left Atrial Appendage Occlusion Relative to Novel and Traditional Oral Anticoagulation for Stroke Prevention in Patients with New-Onset Atrial Fibrillation

Background. Percutaneous left atrial appendage occlusion (LAAO) is a nonpharmacologic approach for stroke prevention in nonvalvular atrial fibrillation (NVAF). No direct comparisons to novel oral anticoagulants (OACs) exists, limiting decision making on the optimal strategy for stroke prevention in NVAF patients. Addressing this gap in knowledge is timely given the recent debate by the US Food and Drug Administration regarding the effectiveness of LAAO. Objective. To assess the cost-effectiveness of LAAO and novel OACs relative to warfarin in patients with new-onset NVAF without contraindications to OAC. Design. A cost-utility analysis using a patient-level Markov micro-simulation decision analytic model was undertaken to determine the lifetime costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratio (ICER) of LAAO and all novel OACs relative to warfarin. Effectiveness and utility data were obtained from the published literature and cost from the Ontario Drug Benefits Formulary and Case Costing Initiative. Results. Warfarin had the lowest discounted QALY (5.13 QALYs), followed by dabigatran (5.18 QALYs), rivaroxaban and LAAO (5.21 QALYs), and apixaban (5.25 QALYs). The average discounted lifetime costs were $15 776 for warfarin, $18 280 for rivaroxaban, $19 156 for apixaban, $20 794 for dabigatran, and $21 789 for LAAO. Apixaban dominated dabigatran and LAAO and demonstrated extended dominance over rivaroxaban. The ICER for apixaban relative to warfarin was $28 167/QALY. Apixaban was preferred in 40.2% of simulations at a willingness-to-pay threshold of $50 000/QALY. Limitations. Assumptions regarding clinical and methodological differences between published studies of each therapy were minimized. Conclusions. Apixaban is the most cost-effective therapy for stroke prevention in patients with new-onset NVAF without contraindications to OAC. Uncertainty around this conclusion exists, highlighting the need for further research.

New oral anticoagulants: their role in stroke prevention in high-risk patients with atrial fibrillation

Based on efficacy, safety, and ease of use, novel oral anticoagulants will likely replace VKAs for many if not most patients with atrial fibrillation. Novel anticoagulants have a lower rate of intracranial hemorrhage compared with vitamin K antagonists. The incidence of other life-threatening bleeds is similar if not lower. Dose adjustments need to be made based on renal function and advanced age. There is at present a need for an antidote for these new drugs.

Non-vitamin K antagonist oral anticoagulants and atrial fibrillation guidelines in practice: barriers to and strategies for optimal implementation

Stroke is a leading cause of morbidity and mortality worldwide. Atrial fibrillation (AF) is an independent risk factor for stroke, increasing the risk five-fold. Strokes in patients with AF are more likely than other embolic strokes to be fatal or cause severe disability and are associated with higher healthcare costs, but they are also preventable. Current guidelines recommend that all patients with AF who are at risk of stroke should receive anticoagulation. However, despite this guidance, registry data indicate that anticoagulation is still widely underused. With a focus on the 2012 update of the European Society of Cardiology (ESC) guidelines for the management of AF, the Action for Stroke Prevention alliance writing group have identified key reasons for the suboptimal implementation of the guidelines at a global, regional, and local level, with an emphasis on access restrictions to guideline-recommended therapies. Following identification of these barriers, the group has developed an expert consensus on strategies to augment the implementation of current guidelines, including practical, educational, and access-related measures. The potential impact of healthcare quality measures for stroke prevention on guideline implementation is also explored. By providing practical guidance on how to improve implementation of the ESC guidelines, or region-specific modifications of these guidelines, the aim is to reduce the potentially devastating impact that stroke can have on patients, their families and their carers.

Edoxaban: an update on the new oral direct factor Xa inhibitor

Edoxaban is a once-daily oral anticoagulant that rapidly and selectively inhibits factor Xa in a concentration-dependent manner. This review describes the extensive clinical development program of edoxaban, including phase III studies in patients with non-valvular atrial fibrillation (NVAF) and symptomatic venous thromboembolism (VTE). The ENGAGE AF-TIMI 48 study (N = 21,105; mean CHADS₂ score 2.8) compared edoxaban 60 mg once daily (high-dose regimen) and edoxaban 30 mg once daily (low-dose regimen) with dose-adjusted warfarin [international normalized ratio (INR) 2.0–3.0] and found that both regimens were non-inferior to warfarin in the prevention of stroke and systemic embolism in patients with NVAF. Both edoxaban regimens also provided significant reductions in the risk of hemorrhagic stroke, cardiovascular mortality, major bleeding and intracranial bleeding. The Hokusai-VTE study (N = 8,292) in patients with symptomatic VTE had a flexible treatment duration of 3–12 months and found that following initial heparin, edoxaban 60 mg once daily was non-inferior to dose-adjusted warfarin (INR 2.0–3.0) for the prevention of recurrent VTE, and also had a significantly lower risk of bleeding events. Both studies randomized patients at moderate-to-high risk of thromboembolic events and were further designed to simulate routine clinical practice as much as possible, with edoxaban dose reduction (halving dose) at randomisation or during the study if required, a frequently monitored and well-controlled warfarin group, a well-monitored transition period at study end and a flexible treatment duration in Hokusai-VTE. Given the phase III results obtained, once-daily edoxaban may soon be a key addition to the range of antithrombotic treatment options.