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

Low Utility of Short-Term Rhythm Assessment Before Long-Term Rhythm Monitoring in Patients With Cryptogenic Stroke

Implantable cardiac monitors are routinely placed for long-term monitoring (LTM) after a period of negative short-term monitoring (STM) to increase atrial fibrillation (AF) detection after a cryptogenic stroke or transient ischemic attack (TIA). Optimizing AF monitoring after a cryptogenic stroke is critical to improve outcomes and reduce costs. We sought to compare the diagnostic yield of STM versus LTM, assess the impact of routine STM on hospitalization length of stay, and perform a financial analysis comparing the current model to a theoretical model wherein patients can proceed directly to LTM. Our retrospective observational cohort study analyzed patients admitted to Montefiore Medical Center between May 2017 and June 2022 with a primary diagnosis of cryptogenic stroke or TIA who underwent Holter device monitoring. Of 396 subjects, STM detected AF in 10 (2.5%) compared with a diagnostic yield of 14.6% for LTM (median time to diagnosis of 76 days). Of the 386 patients with negative STM, 130 (33.7%) received an implantable cardiac monitor while an inpatient, and 256 (66.3%) did not. We calculated a point estimate of 1.67 days delay of discharge attributable to the requirement for STM to precede LTM. Our model showed that the expected cost per patient in the STM-first paradigm is $28,615.33 versus $27,111.24 in the LTM-or-STM paradigm. Considering the relatively lower diagnostic yield of STM and its association with a longer length of stay and higher costs, it may be reasonable to proceed directly to LTM to optimize AF detection after a cryptogenic stroke or TIA.

Atrial Fibrillation Management in 2021: An Updated Comparison of the Current CCS/CHRS, ESC, and AHA/ACC/HRS Guidelines

Given its complexity, the management of atrial fibrillation (AF) has relied increasingly on expert guideline recommendations; however, discrepancies among these professional societies can lead to confusion among practicing clinicians. This article compares the recommendations in the 2019 American Heart Association (AHA)/American College of Cardiology (ACC)/Heart Rhythm Society (HRS), the 2020 European Society of Cardiology (ESC), and the 2020 Canadian Cardiovascular Society/Canadian Heart Rhythm Society (CCS/CHRS) AF guidelines. Although many of the recommendations are fundamentally similar, there are important differences between guidelines. Specifically, key differences are present in: 1) Definitions and classification of AF; 2) The role of opportunistic detection; 3) Symptom and quality-of-life evaluation; 4) Stroke-risk stratification, and the indication for oral anticoagulation (OAC) therapy; 5) the role of aspirin in stroke prevention for AF patients; 6) the antithrombotic regimens employed in the context of coronary artery disease; 7) the role of OAC, and specifically non-vitamin K direct-acting oral anticoagulants (DOACs), in patients with chronic and end-stage renal disease; 8) the target heart rate for patients treated with a rate-control strategy, along with the medications recommended to achieve the heart-rate target; and 9) the role of catheter ablation as first-line therapy or in patients with heart failure. These differences highlight areas of continuing clinical uncertainty where there are important needs and opportunities for future investigative work.

Risk of ischemic stroke in patients with end-stage renal disease receiving peritoneal dialysis with new-onset atrial fibrillation

BACKGROUND

The clinical effect of atrial fibrillation (AF)-related ischemic cardiovascular events in patients undergoing peritoneal dialysis (PD) remains uncertain. This study aimed to investigate the risk of ischemic events in patients undergoing PD with new-onset AF compared with that in patients without AF and ascertain the association between the CHA2DS2-VASc score and risk of ischemic stroke.

METHODS

This nationwide, population-based cohort study used data from Taiwan's National Health Insurance Research Database from 1998 to 2011 for patients receiving PD with or without new-onset AF. The clinical endpoints included ischemic stroke, all-cause death, and in-hospital cardiovascular death.

RESULTS

Patients undergoing PD with new-onset AF (N = 505) had significantly higher risks of ischemic stroke (adjusted hazard ratio [aHR], 1.98; 95% CI, 1.40-2.80), all-cause death (aHR, 1.61; 95% CI, 1.40-1.85), and in-hospital cardiovascular death (aHR, 1.82; 95% CI, 1.50.2.21) compared with those in patients undergoing PD without AF. After considering in-hospital death as a competing risk, AF remained associated with an increased risk of ischemic stroke (hazard ratio [HR], 1.67; 95% CI, 1.17-2.37). The CHA2DS2-VASc score was associated with the risk of ischemic stroke (HR, 1.28; 95% CI, 1.12-1.46).

CONCLUSION

The risks of ischemic stroke, all-cause death, and in-hospital cardiovascular death were significantly higher in patients undergoing PD with AF than those in patients without AF. The CHA2DS2-VASc score remained associated with the risk of ischemic stroke in patients undergoing PD with AF.

The 2020 Canadian Cardiovascular Society/Canadian Heart Rhythm Society Comprehensive Guidelines for the Management of Atrial Fibrillation

The Canadian Cardiovascular Society (CCS) atrial fibrillation (AF) guidelines program was developed to aid clinicians in the management of these complex patients, as well as to provide direction to policy makers and health care systems regarding related issues. The most recent comprehensive CCS AF guidelines update was published in 2010. Since then, periodic updates were published dealing with rapidly changing areas. However, since 2010 a large number of developments had accumulated in a wide range of areas, motivating the committee to complete a thorough guideline review. The 2020 iteration of the CCS AF guidelines represents a comprehensive renewal that integrates, updates, and replaces the past decade of guidelines, recommendations, and practical tips. It is intended to be used by practicing clinicians across all disciplines who care for patients with AF. The Grading of Recommendations, Assessment, Development and Evaluations (GRADE) system was used to evaluate recommendation strength and the quality of evidence. Areas of focus include: AF classification and definitions, epidemiology, pathophysiology, clinical evaluation, screening and opportunistic AF detection, detection and management of modifiable risk factors, integrated approach to AF management, stroke prevention, arrhythmia management, sex differences, and AF in special populations. Extensive use is made of tables and figures to synthesize important material and present key concepts. This document should be an important aid for knowledge translation and a tool to help improve clinical management of this important and challenging arrhythmia.

Canada-wide mixed methods analysis evaluating the reasons for inappropriate emergency department presentation in patients with a history of atrial fibrillation: the multicentre AF-ED trial

OBJECTIVES

The primary objective of this study was to ascertain the reasons for emergency department (ED) attendance among patients with a history of atrial fibrillation (AF).

DESIGN

Appropriate ED attendance was defined by the requirement for an electrical or chemical cardioversion and/or an attendance resulting in hospitalisation or administration of intravenous medications for ventricular rate control. Quantitative and qualitative responses were recorded and analysed using descriptive statistics and content analysis, respectively. Random effects logistic regression was performed to estimate the OR of inappropriate ED attendance based on clinically relevant patient characteristics.

PARTICIPANTS

Participants ≥18 years with a documented history of AF were approached in one of eight centres partaking in the study across Canada (Ontario, Nova Scotia, Alberta and British Columbia).

RESULTS

Of the 356 patients enrolled (67±13, 45% female), the majority (271/356, 76%) had inappropriate reasons for presentation and did not require urgent ED treatment. Approximately 50% of patients(172/356, 48%) were driven to the ED due to symptoms, while the remainder presented on the basis of general fear or anxiety (67/356, 19%) or prior medical advice (117/356, 33%). Random effects logistic regression analysis showed that patients with a history of congestive heart failure were significantly more likely to seek urgent care for appropriate reasons (p=0.03). Likewise, symptom-related concerns for ED presentation were significantly less likely to result in inappropriate visitation (p=0.02). When patients were surveyed on alternatives to ED care, the highest proportion of responses among both groups was in favour of specialised rapid assessment outpatient clinics (186/356, 52%). Qualitative content analysis confirmed these results.

CONCLUSIONS

Improved education focused on symptom management and alleviating disease-related anxiety as well as the institution of rapid access arrhythmias clinics may reduce the need for unnecessary healthcare utilisation in the ED and subsequent hospitalisation.

TRIAL REGISTRATION NUMBER

NCT03127085.

Subclinical Atrial Fibrillation and Risk of Stroke: Past, Present and Future

Subclinical atrial fibrillation (SCAF) describes asymptomatic episodes of atrial fibrillation (AF) that are detected by cardiac implantable electronic devices (CIED). The increased utilization of CIEDs renders our understanding of SCAF important to clinical practice. Furthermore, 20% of AF present initially as a stroke event and prolonged cardiac monitoring of stroke patients is likely to uncover a significant prevalence of SCAF. New evidence has shown that implanting cardiac monitors into patients with no history of atrial fibrillation but with risk factors for stroke will yield an incidence of SCAF approaching 30–40% at around three years. Atrial high rate episodes lasting longer than five minutes are likely to represent SCAF. SCAF has been associated with an increased risk of stroke that is particularly significant when episodes of SCAF are greater than 23 h in duration. Longer episodes of SCAF are incrementally more likely to progress to episodes of SCAF >23 h as time progresses. While only around 30–40% of SCAF events are temporally related to stroke events, the presence of SCAF likely represents an important risk marker for stroke. Ongoing trials of anticoagulation in patients with SCAF durations less than 24 h will inform clinical practice and are highly anticipated. Further studies are needed to clarify the association between SCAF and clinical outcomes as well as the factors that modify this association.

The Guideline-Policy Gap in Direct-Acting Oral Anticoagulants Usage in Atrial Fibrillation: Evidence, Practice, and Public Policy Considerations

Atrial fibrillation has a high disease burden-both in prevalence and associated consequences. Despite anticoagulation being an effective treatment in atrial fibrillation, stroke prevention is slow to reflect evidence-based practice. Real-world data reveal a substantial portion of patients who would benefit from anticoagulation, yet do not receive it adequately or at all. A large part of this suboptimal treatment is due to the underutilization of direct oral anticoagulants (DOACs). In response to abundant evidence published over a short timeframe, international guidelines have adopted DOAC usage ahead of policy and fund holders. This paper reviews the evidence and values that influence published guidelines, patient-physician decision making, and policy framework on DOAC usage. An important factor is the access gap between patients who qualify for DOAC according to evidence-based guidelines and the subset of this cohort who are eligible for DOAC based on government funded policy. We analyse the Canadian health system in detail-including drug approval and funding process. Health care systems in other countries are explored, with emphasis on similar universal health care systems that may help overcome barriers common to Canada. We will discuss strategies to: (1) improve awareness of the risk and preventability of stroke; (2) enable physicians to provide evidence-based DOAC usage; (3) empower patients to improve adherence and persistence; (4) collect real-life data that encourages patient self-monitoring, physician outcomes auditing, and building evidence that is useful for policy makers; and (5) use postmarketing data in negotiating shared risk management between pharmaceuticals and government to improve access to DOACs.

Blinded Randomized Trial of Anticoagulation to Prevent Ischemic Stroke and Neurocognitive Impairment in Atrial Fibrillation (BRAIN-AF): Methods and Design

BACKGROUND

Compelling evidence showing a link between atrial fibrillation (AF) and cognitive decline and dementia is accumulating.

METHODS

Blinded Randomized Trial of Anticoagulation to Prevent Ischemic Stroke and Neurocognitive Impairment in Atrial Fibrillation (BRAIN-AF) is a prospective, multicentric, double-blind, randomized-controlled trial, recruiting patients with nonvalvular AF and a low risk of stroke. Patients with a high risk of bleeding will be excluded from the study. Participants will be randomized to receive either rivaroxaban (15 mg daily) or standard of care (placebo in patients without vascular disease or acetylsalicylic acid 100 mg daily in patients with vascular disease).

RESULTS

The primary outcome is the composite of stroke, transient ischemic attack, and cognitive decline (defined by a decrease in the Montreal Cognitive Assessment score ≥ 3 at any follow-up visit after baseline). Approximately 3250 patients will be enrolled in approximately 130 clinical sites until 609 adjudicated primary outcome events have occurred.

CONCLUSIONS

BRAIN-AF determines whether oral anticoagulation therapy with rivaroxaban compared with standard of care reduces the risk of stroke, transient ischemic attack, or cognitive decline in patients with nonvalvular AF and a low risk of stroke.

Stroke risk stratification in atrial fibrillation: a review of common risk factors

Atrial Fibrillation (AF) has become a major global health concern being the most common sustained arrhythmia in clinical practice. Risk factors for AF include congestive heart failure, hypertension, increasing age and diabetes. Many of these factors also increase the risk for thromboembolism and ischemic stroke in AF patients. Great efforts have been made from the latter part of the 20th century towards developing an ideal stroke risk stratification tool in AF with the aim of reducing the incidence of stroke in AF patients and the limiting unnecessary use of thromboprophylaxis. The thromboembolic risks posed by AF with valvular heart disease are an important subgroup that contributes to a significant proportion of stroke in AF patients globally. We review the evolution of stroke risk stratification and summarize the guidelines for stroke prevention in non-valvular AF as well as AF with valvular heart disease, and the most recent recommendations on stroke prevention in AF patients. Abbreviations: AF: Atrial Fibrillation; ACS: Acute Coronary Syndrome; CAD: Coronary Artery Disease; CCF: Congestive Cardiac Failure; DM: Diabetes Mellitus; EHRA: Evaluated Heartvalves, Rheumatic or Artificial; ICH: Intracranial Hemorrhage; NOACs: Novel Oral Anticoagulants; OAC: Oral Anticoagulants; PAD: Peripheral Arterial Disease ; TIA: Transient Ischemic Attack; VHD: Valvular Heart Disease.

Anticoagulation risk assessment for patients with non-valvular atrial fibrillation and venous thromboembolism: A clinical review

Non-valvular atrial fibrillation and venous thromboembolism anticoagulation risk assessment tools have been increasingly utilized to guide implementation and duration of anticoagulant therapy. Anticoagulation significantly reduces stroke and recurrent venous thromboembolism risk, but comes at the cost of increased risk of major and clinically relevant non-major bleeding. The decision for anticoagulation in high-risk patients is complicated by the fact that many risk factors associated with increased thromboembolic risk are simultaneously associated with increased bleeding risk. Traditional risk assessment tools rely heavily on age, sex, and presence of cardiovascular comorbidities, with newer tools additionally taking into account changes in risk factors over time and novel biomarkers to facilitate more personalized risk assessment. These tools may help counsel and inform patients about the risks and benefits of starting or continuing anticoagulant therapy and can identify patients who may benefit from more careful management. Although the ability to predict anticoagulant-associated hemorrhagic risk is modest, ischemic and bleeding risk scores have been shown to add significant value to therapeutic management decisions. Ultimately, further work is needed to optimally implement accurate and actionable risk stratification into clinical practice.

Prior Authorization and Canadian Public Utilization of Direct-Acting Oral Anticoagulants

Purpose:

Provincial public drug formularies in Canada have different mechanisms for reimbursement of direct-acting oral anticoagulants (DOACs). We investigate how these differences influence DOAC utilization and expenditure across the country.

Methods:

We conducted a population-based, cross-sectional study of all out-patient prescriptions for OACs dispensed to public beneficiaries between January 1, 2010, and June 30, 2015. We calculated quarterly rates of OAC use and expenditures stratified by OAC type and province.

Results:

The greatest increase in quarterly rates of DOAC utilization occurred in provinces with more liberal mechanism of drug coverage: Ontario by 462%, Alberta by 425% and Quebec by 1,924%. This translated to increased expenditure on overall OAC by 270%, 204% and 390%, respectively. In contrast, provinces with more stringent mechanisms had low rates of DOAC utilization and expenditure.

Conclusions:

DOAC utilization and expenditure is considerably different across Canada, associated with provincial difference in reimbursement mechanism.

Non-vitamin K antagonist oral anticoagulants in atrial fibrillation patients with bioprosthetic valves

INTRODUCTION

The non-vitamin K antagonist oral anticoagulants (NOACs), which include dabigatran, apixaban, edoxaban and rivaroxaban, are preferred over vitamin K antagonists for stoke prevention in most patients with non-valvular atrial fibrillation. The NOACs are contraindicated in atrial fibrillation patients with rheumatic mitral stenosis or mechanical heart valves. There is evidence that bioprosthetic heart valves are less thrombogenic than mechanical heart valves, but it is unknown whether the risk of thromboembolism in atrial fibrillation patients with bioprosthetic valves differs from that in patients without such valves. Areas covered: The authors present a review of the efficacy and safety evidence surrounding the use of NOACs for stroke prevention in atrial fibrillation patients with bioprosthetic heart valves. Expert commentary: While the data is limited, there is no significant difference in thromboembolic, and bleeding outcomes in patients with AF and bioprosthetic heart valves treated with NOAC therapy. Future studies are required before definitive conclusions can be drawn regarding the safety and efficacy of NOAC therapy in AF patients bioprosthetic heart valves.

Atrial fibrillation is related to lower incidence of deep venous thrombosis in patients with pulmonary embolism

Background

Atrial fibrillation (AF) is an established risk factor of left atrial thrombosis and systemic embolism. Traditionally pulmonary embolism (PE) is a recognized complication of deep vein thrombosis (DVT). However, whether AF is responsible for right atrial thrombosis and leads to PE has not been examined.

Methods

We retrospectively analyzed medical records of patients with confirmed diagnosis of PE with AF (study group) from 2002-2015. Patients with PE without AF, matched by age and sex, served as controls (control group). The CHA₂DS₂-VASc and CHADS₂ scores were classified into two categories, low-intermediate (<2 points) and high-risk (≥2 points).

Results

A total of 330 patients (110 in study group and 220 in control group). The study group had significantly lower incidence of newly diagnosed DVT (21% vs. 44%, P<0.001), previous history of DVT (6% vs. 17%, P=0.006) and recent surgery or trauma (10% vs. 23%, P=0.004) compared to the control group. When stratified by the CHADS₂ score, 49 patients (44.5%) were considered low-intermediate risk. This proportion significantly differed when stratified using CHA₂DS₂-VASc, in which 13 patients (13.6%) were considered low-intermediate risk, P<0.001.

Conclusions

The incidence of DVT was much lower in the study group, suggesting the possibility of clots originated from the right heart that may increase the risk of PE. The CHA₂DS₂-VASc scoring system might be more sensitive for prediction and stratification of the PE in AF patients than the CHADS₂ score.

Evaluating the potential for pharmacists to prescribe oral anticoagulants for atrial fibrillation

Background

Oral anticoagulant therapy (OAC) to prevent atrial fibrillation (AF)-related strokes remains poorly used. Alternate strategies, such as community pharmacist prescribing of OAC, should be explored.

Methods

Approximately 400 pharmacists, half with additional prescribing authority (APA), randomly selected from the Alberta College of Pharmacists, were invited to participate in an online survey over a 6-week period. The survey consisted of demographics, case scenarios assessing appropriateness of OAC (based on the 2014 Canadian Cardiovascular Society AF guidelines) and perceived barriers to prescribing. Regression analysis was performed to determine predictors of knowledge.

Results

A total of 35% (139/397) of pharmacists responded to the survey, and 57% of these had APA. Depending on the case scenario, 55% to 92% of pharmacists correctly identified patients eligible for stroke prevention therapy, but only about a half selected the appropriate antithrombotic agent; there was no difference in the knowledge according to APA status. In multivariable analysis, predictors significantly associated with guideline-concordant prescribing were having the pharmacist interact as part of an interprofessional team (p = 0.04) and direct OAC (DOAC) self-efficacy (confidence in ability to extend, adapt, initiate or alter prescriptions; p = 0.02). Barriers to prescribing OAC for APA pharmacists included a lack of AF and DOAC knowledge and preference for consulting the physician first, but these same pharmacists also identified difficulty in contacting the physician as a major barrier.

Interpretation and Conclusion

Community pharmacists can identify patients who would benefit from stroke prevention therapy in AF. However, physician collaboration and further training on AF and guidelines for prescribing OAC are needed.

Prevention of Left Ventricular Thrombus Formation and Systemic Embolism After Anterior Myocardial Infarction: A Systematic Literature Review

BACKGROUND

Anterior myocardial infarction (MI) with apical dysfunction is associated with an increased risk of left ventricular thrombus (LVT) formation and systemic embolism (SE). However, the role for prophylactic anticoagulation in current practice is a matter of debate.

METHODS

We conducted a systematic review of peer-reviewed original articles in either English or French on the benefit of combining anticoagulation with standard therapy for the prevention of LVT/SE after MI by searching PubMed, Ovid/MedLine/Embase, the Cochrane Library, and Google Scholar.

RESULTS

Of 7382 identified records, 14 were retained for analysis. Nine articles addressed anticoagulation for patients not treated with percutaneous coronary intervention (PCI). Another 5 included at least some patients treated with PCI. Only 1 study specifically addressed exclusively a primary PCI population. Some studies showed a benefit for combining anticoagulation with standard therapy in patients not treated with PCI, but results were inconsistent. No evidence of benefit was reported when PCI patients were included and 1 study reported a signal for net harm. There was important interstudy heterogeneity and methodological limitations. Studies were likely individually underpowered.

CONCLUSIONS

The available studies of LVT/SE prevention after MI lacked statistical power and are heterogeneous in terms of treatments, revascularization methods, background medical therapy, and study design. We conclude that there is presently no compelling evidence for or against combining anticoagulation with standard therapy for post-MI patients with apical dysfunction after primary PCI, and inconsistent evidence supporting prophylaxis after thrombolysis. An appropriately powered randomized trial is required to answer this clinically relevant question.

Subclinical Atrial Fibrillation in Older Patients

BACKGROUND

Long-term continuous electrocardiographic monitoring shows a substantial prevalence of asymptomatic, subclinical atrial fibrillation (SCAF) in patients with pacemakers and patients with cryptogenic stroke. Whether SCAF is also common in other patients without these conditions is unknown.

METHODS

We implanted subcutaneous electrocardiographic monitors (St. Jude CONFIRM-AF) in patients ≥65 years of age attending cardiovascular or neurology outpatient clinics if they had no history of atrial fibrillation but had any of the following: CHA₂DS₂-VASc score of ≥2, sleep apnea, or body mass index >30 kg/m². Eligibility also required either left atrial enlargement (≥4.4 cm or volume ≥58 mL) or increased (≥290 pg/mL) serum NT-proBNP (N-terminal pro-B-type natriuretic peptide). Patients were monitored for SCAF lasting ≥5 minutes.

RESULTS

Two hundred fifty-six patients were followed up for 16.3±3.8 months. Baseline age was 74±6 years; mean CHA₂DS₂-VASc score was 4.1±1.4; left atrial diameter averaged 4.7±0.8 cm; and 48% had a prior stroke, transient ischemic attack, or systemic embolism. SCAF ≥5 minutes was detected in 90 patients (detection rate, 34.4%/y; 95% confidence interval [CI], 27.7-42.3). Baseline predictors of SCAF were increased age (hazard ratio [HR] per decade, 1.55; 95% CI, 1.11-2.15), left atrial dimension (HR per centimeter diameter, 1.43; 95% CI, 1.09-1.86), and blood pressure (HR per 10 mm Hg, 0.87; 95% CI, 0.78-0.98), but not prior stroke. The rate of occurrence of SCAF in those with a history of stroke, systemic embolism, or transient ischemic attack was 39.4%/y versus 30.3%/y without (P=0.32). The cumulative SCAF detection rate was higher (51.9%/y) in those with left atrial volume above the median value of 73.5 mL.

CONCLUSIONS

SCAF is frequently detected by continuous electrocardiographic monitoring in older patients without a history of atrial fibrillation who are attending outpatient cardiology and neurology clinics. Its clinical significance is unclear.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01694394.

Predicting in a predicament: Stroke and hemorrhage risk prediction in dialysis patients with atrial fibrillation

Whether to anticoagulate dialysis patients with atrial fibrillation is a common clinical dilemma with limited high-quality data to inform decision-making. While the efficacy and safety of anticoagulation for stroke prevention in dialysis patients with atrial fibrillation has long been debated and remains unclear, the more upstream issue of stroke risk assessment from atrial fibrillation has received relatively little attention. In the general population, a handful of risk scores to help predict stroke and hemorrhage risk in the setting of atrial fibrillation are widely validated and applied in clinical practice. But are they applicable to the dialysis population? The most commonly used stroke risk scores, CHADS2 and CHA2DS2-VASC, have limited validation in the dialysis population, and when validated, have shown poor performance (c-statistics <0.70). Stroke risk scores derived in the general atrial fibrillation population may perform poorly in dialysis patients for a number of reasons. Dialysis patients have unique stroke risk factors, such as chronic inflammation and vascular calcification, and a much higher competing risk of death, none of which are accounted for in current risk scores. Further complicating the dilemma of anticoagulation is hemorrhage risk, which is known to be exceedingly high in dialysis patients. Currently available hemorrhage risk scores, such as HAS-BLED, have not been validated in dialysis patients and will likely underestimate hemorrhage risk. Moving forward, risk tools specific to the dialysis population are needed to accurately assess and balance stroke and hemorrhage risks in dialysis patients with atrial fibrillation.

2017 consensus of the Asia Pacific Heart Rhythm Society on stroke prevention in atrial fibrillation

Atrial fibrillation (AF) is the most common sustained arrhythmia, causing a 2-fold increase in mortality and a 5-fold increase in stroke. The Asian population is rapidly aging, and in 2050, the estimated population with AF will reach 72 million, of whom 2.9 million may suffer from AF-associated stroke. Therefore, stroke prevention in AF is an urgent issue in Asia. Many innovative advances in the management of AF-associated stroke have emerged recently, including new scoring systems for predicting stroke and bleeding risks, the development of non-vitamin K antagonist oral anticoagulants (NOACs), knowledge of their special benefits in Asians, and new techniques. The Asia Pacific Heart Rhythm Society (APHRS) aimed to update the available information, and appointed the Practice Guideline sub-committee to write a consensus statement regarding stroke prevention in AF. The Practice Guidelines sub-committee members comprehensively reviewed updated information on stroke prevention in AF, emphasizing data on NOACs from the Asia Pacific region, and summarized them in this 2017 Consensus of the Asia Pacific Heart Rhythm Society on Stroke Prevention in AF. This consensus includes details of the updated recommendations, along with their background and rationale, focusing on data from the Asia Pacific region. We hope this consensus can be a practical tool for cardiologists, neurologists, geriatricians, and general practitioners in this region. We fully realize that there are gaps, unaddressed questions, and many areas of uncertainty and debate in the current knowledge of AF, and the physician׳s decision remains the most important factor in the management of AF.

Nonvitamin K antagonist oral anticoagulant use in patients with renal impairment

The nonvitamin K antagonist oral anticoagulants (NOACs), also referred to as direct oral anticoagulants (DOACs), dabigatran, apixaban, edoxaban, and rivaroxaban, have emerged as effective alternatives to vitamin K antagonists (VKAs) across several indications, including the prevention of stroke and systemic embolism (SSE) in patients with atrial fibrillation (AF) and the treatment of venous thromboembolism (VTE). Their use in patients with renal impairment is of particular importance, given the prevalence of renal dysfunction in the indicated populations and the impact of renal function on the metabolism of the NOACs. This publication reviews the pharmacokinetic/pharmacodynamic properties of the NOACs and clinical trial results for patients with renal impairment within the AF and VTE indications. Pharmacokinetic/pharmacodynamic data show the NOACs are dependent on renal clearance to varying extents. Relative to VKAs, the efficacy and safety of the NOACs is preserved in patients with moderate renal impairment. The dosing recommendations for patients with renal impairment differ depending on the NOAC, whereby some of the NOACs require dose reductions based solely on renal function, while others require consideration of additional criteria. However, despite these specific dosing recommendations, emerging real-world evidence suggests patients are not being dosed appropriately, indicating a possible knowledge gap. Adherence to recommended dosing algorithms has implications on the optimal efficacy and safety of the NOACs. To this end, renal function should be assessed in patients on a NOAC, as worsening of renal function may warrant change in the dose of a NOAC or change in oral anticoagulant.

Contemporary Atrial Fibrillation Management: A Comparison of the Current AHA/ACC/HRS, CCS, and ESC Guidelines

In this article we compare and contrast the current recommendations, and highlight the important differences, in the American College of Cardiology/American Heart Association/Heart Rhythm Society, European Society of Cardiology, and Canadian Cardiovascular Society atrial fibrillation (AF) guidelines. Although many of the recommendations of the various societies are similar, there are important differences in the methodologies underlying their development and the specific content. Specifically, key differences can be observed in: (1) the definition of nonvalvular AF, which subsequently affects anticoagulation choices and candidacy for non-vitamin K antagonist oral anticoagulants; (2) the symptom score used to guide management decisions and longitudinal patient profiling; (3) the stroke risk stratification algorithm used to determine indications for oral anticoagulant therapy; (4) the role of acetylsalicylic acid in stroke prevention in AF; (5) the antithrombotic regimens used in the context of coronary artery disease, acute coronary syndromes, and percutaneous coronary intervention; (6) the rate control target and medications recommended to achieve the target; and (7) the role of "first-line" catheter ablation, open surgical ablation, and left atrial appendage exclusion.

Evolving Treatments for Arterial and Venous Thrombosis: Role of the Direct Oral Anticoagulants

The direct oral anticoagulants (DOACs) represent a major advance in oral anticoagulant therapy and have replaced the vitamin K antagonists as the preferred treatment for many indications. By simplifying long-term anticoagulant therapy and improving its safety, the DOACs have the potential to reduce the global burden of thrombosis. Postmarketing studies suggest that the favorable results achieved with DOACs in the randomized controlled trials can be readily translated into practice, but highlight the need for appropriate patient, drug and dose selection, and careful follow-up. Leveraging on their success to date, ongoing studies are assessing the utility of DOACs for the prevention of thrombosis in patients with embolic stroke of unknown source, heart failure, coronary artery disease, peripheral artery disease, antiphospholipid syndrome, and cancer. The purpose of this article is to (1) review the pharmacology of the DOACs, (2) describe the advantages of the DOACs over vitamin K antagonists, (3) summarize the experience with the DOACs in established indications, (4) highlight current challenges and limitations, (5) highlight potential new indications; and (6) identify future directions for anticoagulant therapy.

Managing Stroke During Transcatheter Aortic Valve Replacement

Transcatheter aortic valve replacement (TAVR) has become the default treatment option for high-risk patients with aortic stenosis and an alternative to surgical aortic valve replacement in intermediate-risk patients. There are, however, concerns regarding strokes during TAVR. Reported stroke rates vary strongly depending on the type of study, stroke definition, cohort and study period. Furthermore, stroke after TAVR occurs in three distinct phases: 1) early high-risk, directly procedure related; 2) elevated risk interval between day 2 and day 30; 3) late hazard interval. Each of these phases is caused by the different aetiologies of stroke. This review summarises the different aetiologies and potential strategies for managing stroke during TAVR.

Atrial fibrillation, liver disease, antithrombotics and risk of cerebrovascular events: A population-based cohort study

BACKGROUND

Whether patients with atrial fibrillation (AF) and liver disease are also prone to cerebrovascular events and respond similarly favorably to antithrombotic therapy remains under-investigated.

METHODS

Patients ≥18years with newly-diagnosed AF in the period 2005 to 2009 were scrutinized from the "Longitudinal Health Insurance Database 2005" (1 million beneficiaries) of Taiwan's National Health Insurance Institute. Patients were categorized into the Liver (N=433) or the Non-liver (N=3490) cohort according to whether they had a diagnosis of advanced liver disease. Patients were then followed to determine cumulative incidence of hospitalization-requiring cerebrovascular events, preventive effects of antithrombotics, and predictors of cerebrovascular events by Cox regression analysis.

RESULTS

Within a mean follow-up of 3.3±1.4years, ischemic stroke (89.2 vs. 50.3 per 1000 person-years, adjusted HR 1.502, 95% CI 1.207-1.868, p<0.001) and overall cerebrovascular events (102.3 vs. 56.4 per 1000 person-years, adjusted HR 1.535, 95% CI 1.251-1.883, p<0.001) occurred significantly more often in the Liver than in the Non-liver cohort. Cox models identified aging (≥65years), DM, and CHA2DS-VASc score≥2 points as risk factors for overall cerebrovascular events in the Liver cohort, whereas antiplatelet agents (HR 0.932, 95% CI 0.128-6.803, p=NS) and vit-K antagonistic anticoagulants (HR 1.087, 95% CI 0.150-7.862, p=NS) showed no correlation.

CONCLUSION

AF patients comorbid with advanced liver disease are more vulnerable to ischemic and therein overall cerebrovascular events, especially in those with old age, DM, or high CHA2DS-VASc scores. This propensity to cerebrovascular events, however, can't be altered by antithrombotic therapy.

Novel oral anticoagulant management issues for the stroke clinician

BACKGROUND

Four nonvitamin K antagonist oral anticoagulants (NOACs) are approved for stroke prevention in patients with nonvalvular atrial fibrillation (NVAF).

AIMS

In this review, we assemble available evidence for the best management of ischemic and hemorrhagic stroke patients in the context of NOAC use.

SUMMARY OF REVIEW

NOACs provide predictable anticoagulation with fixed dosages. The direct thrombin inhibitor dabigatran and direct factor Xa inhibitors apixaban, edoxaban, and rivaroxaban are all noninferior to warfarin for the prevention of ischemic stroke and systemic embolism and are associated with reduced incidence of intracranial hemorrhage. While these agents offer treatment options for NVAF patients, they also present challenges specific to the clinician managing cerebrovascular disease patients.

CONCLUSIONS

We summarize available evidence and current approaches to the initiation, dosing, monitoring and potential reversal of NOACs in stroke patients.

CHA2DS2-VASc Recalibration With an Additional Age Category (50-64 Years) Enhances Stroke Risk Stratification in Chinese Patients With Atrial Fibrillation

BACKGROUND

Chinese patients with atrial fibrillation (AF) and a low CHA₂DS₂-VASc have a disproportionately high ischemic stroke risk; nonetheless, little is known about the impact of age on ischemic stroke risk in this population. In this study, we aimed to examine the age-related ischemic stroke risk in Chinese patients with nonvalvular AF without other risk factors for stroke.

METHODS

This was a hospital-based observational registry.

RESULTS

A total of 1198 Chinese patients with AF (mean age, 73.6 ± 16.5 years; male sex, 53.3%) were included in this analysis. The mean CHA₂DS₂-VASc and HAS-BLED score were 1.81 ± 1.00 and 1.32 ± 0.77, respectively, and none of the patients was prescribed antiplatelet or anticoagulation therapy. After a mean follow-up of 2.95 years, there were 234 ischemic strokes (19.5%), with an annual ischemic stroke incidence of 6.62%/y. The overall annual ischemic stroke risk was 0.43%/y, 5.87%/y, 7.49%/y, and 8.04%/y for age groups < 50 years, 50-64 years, 65-74 years, and ≥ 75 years, respectively. There was a 10- to 20-fold gradient in ischemic stroke risk that increased sharply after the age of 50 years. The hazard ratios were 1.0, 13.0, 19.3, and 21.6 for age groups < 50 years, 50-64 years, 65-74 years and ≥ 75 years, respectively (P for trend < 0.0001). Similar trends were also observed in both male and female patients with AF.

CONCLUSIONS

Chinese patients with AF and a low CHA₂DS₂-VASc were at a disproportionally high risk of ischemic stroke. Chinese patients between 50 and 64 years have a high risk for stroke despite a low CHA₂DS₂-VASc and a low bleeding risk. Only patients aged < 50 years have a truly low risk.

Time in Therapeutic Range and Percentage of International Normalized Ratio in the Therapeutic Range as a Measure of Quality of Anticoagulation Control in Patients With Atrial Fibrillation

BACKGROUND

Time in therapeutic range (TTR), albeit the standard measure of quality of anticoagulation control for warfarin, is underused in everyday clinical practice because of its tedious calculation. In contrast, the percentage of international normalized ratio measurements in range (PINRR) is a convenient alternative. Our objective was to investigate the correlation between PINRR and TTR and whether PINRR has clinical utility for prediction of ischemic stroke and intracranial hemorrhage in a "real-world" atrial fibrillation (AF) cohort.

METHODS

This is an observational study based on a hospital-based AF registry.

RESULTS

Among 1428 Chinese patients with AF who were taking warfarin (76.2 ± 8.7 years; mean CHA₂DS₂-VASc, 4.2 ± 1.6 and HAS-BLED, 2.3 ± 0.9), mean and median TTR values were 38.2% ± 24.4% and 38.8% (interquartile range, 17.9% and 56.2%), respectively. Patients with TTR ≥ 65% (14.8%) had a lower annual risk of ischemic stroke (3.04% per year) than did those with TTR < 65% (5.35% per year). Mean and median PINRR were 34.3% ± 17.1% and 34.2% (interquartile range, 22.7% and 46.0%), respectively. TTR significantly correlated with PINRR in a linear fashion (r = 0.81; P < 0.0001). A cutoff of PINRR ≤ 56.1% was a good discriminator of TTR < 65%, with a high sensitivity (98.3%) and positive predictive value (91.9%). The annual ischemic stroke risk in patients with PINRR > 56.1% was 2.56% per year, lower than those with TTR ≥ 65% (3.04% per year). Patients with PINRR > 56.1% had an annual incidence of intracranial hemorrhage comparable to those with TTR ≥ 65% (0.49% per year vs 0.68% per year).

CONCLUSIONS

Among patients with AF who are taking warfarin, the PINRR is a user-friendly alternative to TTR, having a high sensitivity and positive predictive value in predicting TTR. As with TTR, PINRR is associated with clinical adverse events, ie, ischemic stroke and intracranial hemorrhage.