Clinical update on the management of atrial fibrillation

Low-dose aspirin for primary and secondary prevention of cardiovascular events in Denmark 1998-2018

Randomised controlled trials have shown a neutral or even unfavourable risk–benefit balance of aspirin for primary prevention of cardiovascular events. Using Danish nationwide registries, we investigated aspirin use and associated risks during the past two decades (1998–2018). We linked individual patient data on repeated aspirin redemptions with registered hospital ICD-10 diagnoses of atherosclerotic cardiovascular disease and bleedings. The prevalence of aspirin use among 1.1 million Danish adults fluctuated over the 20-year study period peaking in 2008 with 8.5% (5.4% primary prevention) and dropping to 5.1% (3.1% primary prevention) in 2018. Aspirin use showed strong age dependency, and 21% of individuals > 80 years were treated with aspirin for primary prevention in 2018. Medication adding to bleeding risk was used concurrently by 21% of all aspirin users in 2018. The incidence of major bleedings were similar with primary and secondary prevention aspirin use and highest in elderly (2 per 100 patient years among individuals > 80 years in 2018). In conclusion, low-dose aspirin use for primary prevention of cardiovascular events remains prevalent. The widespread use of aspirin, especially among older adults, and substantial concomitant use of medications adding to bleeding risk warrant increased focus on discontinuation of inappropriate aspirin use.

Ranolazine in the prevention and treatment of atrial fibrillation: A protocol for meta-analysis

BACKGROUND

Atrial fibrillation (AF) is the most common clinical arrhythmia and a major cause of morbidity and mortality in clinical practice. This study aims to determine the ranolazine for prevention and treatment of atrial fibrillation.

METHOD

This study adheres to the Preferred Reporting Items for Systematic Reviews and Meta-analysis for Protocols. Chinese electronic Database (CBM, Wanfang, and CNKI) and international electronic databases (PubMed, Embase, Cochrane Library, and Web of Science) will be searched for all relevant published articles. We will apply no language or the year of publication restrictions. Study selection, data collection, and assessment of study bias will be conducted independently by a pair of independent reviewers. The Cochrane risk of bias (ROB) tool will be used for the risk of bias assessment. The quality of evidence will be evaluated by Grading of Recommendations Assessment Development and Evaluation (GRADE) system. The statistical analysis of this meta-analysis will be calculated by Review manager version 5.3.

RESULTS

The results of this study will be published in a peer-reviewed journal.

CONCLUSION

This review will evaluate the value of ranolazine interventions for patients with AF, and provide meaningful conclusions or high-level evidence for clinical practice and further research.

TRIAL REGISTRATION

This study protocol was registered in open Science framework (OSF), (Registration DOI: 10.17605/OSF.IO/T6W9Q).

Cardiac potassium inward rectifier Kir2: Review of structure, regulation, pharmacology, and arrhythmogenesis

Potassium inward rectifier channel Kir2 is an important component of terminal cardiac repolarization and resting membrane stability. This functionality is part of balanced cardiac excitability and is a defining feature of excitable cardiac membranes. “Gain-of-function” or “loss-of-function” mutations in KCNJ2, the gene encoding Kir2.1, cause genetic sudden cardiac death syndromes, and loss of the Kir2 current I_K1 is a major contributing factor to arrhythmogenesis in failing human hearts. Here we provide a contemporary review of the functional structure, physiology, and pharmacology of Kir2 channels. Beyond the structure and functional relationships, we will focus on the elements of clinically used drugs that block the channel and the implications for treatment of atrial fibrillation with I_K1-blocking agents. We will also review the clinical disease entities associated with KCNJ2 mutations and the growing area of research into associated arrhythmia mechanisms. Lastly, the presence of Kir2 channels has become a tipping point for electrical maturity in induced pluripotent stem cell-derived cardiomyocytes (iPS-CMs) and highlights the significance of understanding why Kir2 in iPS-CMs is important to consider for Comprehensive In Vitro Proarrhythmia Assay and drug safety testing.

Photoplethysmography based atrial fibrillation detection: a review

Atrial fibrillation (AF) is a cardiac rhythm disorder associated with increased morbidity and mortality. It is the leading risk factor for cardioembolic stroke and its early detection is crucial in both primary and secondary stroke prevention. Continuous monitoring of cardiac rhythm is today possible thanks to consumer-grade wearable devices, enabling transformative diagnostic and patient management tools. Such monitoring is possible using low-cost easy-to-implement optical sensors that today equip the majority of wearables. These sensors record blood volume variations-a technology known as photoplethysmography (PPG)-from which the heart rate and other physiological parameters can be extracted to inform about user activity, fitness, sleep, and health. Recently, new wearable devices were introduced as being capable of AF detection, evidenced by large prospective trials in some cases. Such devices would allow for early screening of AF and initiation of therapy to prevent stroke. This review is a summary of a body of work on AF detection using PPG. A thorough account of the signal processing, machine learning, and deep learning approaches used in these studies is presented, followed by a discussion of their limitations and challenges towards clinical applications.

Veterans Perceptions of Satisfaction and Convenience with Anticoagulants for Atrial Fibrillation: Warfarin versus Direct Oral Anticoagulants

BACKGROUND

Atrial fibrillation (AFib) is associated with high morbidity and mortality. Traditionally, AFib was treated with warfarin, yet recent evidence suggests patients may favor direct oral anticoagulants (DOACs). Variation in preferences is common and we explored patients' perceptions of satisfaction and convenience of DOACs versus warfarin within the Veterans Health Administration (VA).

PATIENTS AND METHODS

We administered a cross-sectional survey, the Perception of Anticoagulant Treatment Questionnaire 2 (PACT-Q2), to Veterans residing in New England, age ≥65, diagnosed with AFib, and actively taking anticoagulant medication in fiscal year 2018. Survey recipients were randomly selected among patients on warfarin (n=200) or DOACs (n=200). A selection of survey respondents agreed to a follow-up semi-structured interview (n=16) to further investigate perceptions of satisfaction and convenience.

RESULTS

Of 400 patients, 187 completed the PACT-Q2 survey (49% on DOACs; 51% on warfarin). DOACs received significantly higher convenience ratings than warfarin (87.6, SD 13.5 vs 81.1, SD 18.8; p=0.007); there was no difference in satisfaction (64.2, SD 20.5 SD, warfarin vs, 67.3, SD 19.4, DOACs). Interview results showed that participants perceived their treatment to be convenient. However, participants expressed challenges related to the convenience of taking warfarin or DOACs, such as warfarin users having to follow dietary recommendations or DOAC users desiring some additional monitoring to answer questions or concerns. Overall, warfarin and DOAC users reported satisfaction with ongoing monitoring methods, although a few DOAC users expressed uncertainties with the frequency of monitoring. For most participants, concerns about side effects did not differ by anticoagulant type nor affect satisfaction.

CONCLUSION

Our survey and interview results showed variable patient satisfaction and perceptions of convenience with both DOACs and warfarin. Although DOACs are increasingly prescribed for AFib, some Veterans felt that regular follow-up on warfarin was advantageous. Our findings demonstrate the importance of patient-centered decision-making in AFib treatment in the VA patient population.

Laboratory Assessment of the Anticoagulant Activity of Apixaban in Patients With Nonvalvular Atrial Fibrillation

Our aim is to determine the most appropriate laboratory tests, besides anti-factor Xa (anti-FXa) chromogenic assays, to estimate the degree of anticoagulation with apixaban and compare it with that of rivaroxaban in real-world patients. Twenty patients with nonvalvular atrial fibrillation treated with apixaban 5 mg twice daily and 20 patients on rivaroxaban 20 mg once daily were studied. Conventional coagulation tests, thrombin generation assay (TGA), and thromboelastometry (nonactivated TEM [NATEM] assay) were performed in the 40 patients and 20 controls. The anti-FXa chromogenic assays were used to measure apixaban and rivaroxaban plasma levels. The NATEM measurements showed no significant difference between the 2 groups of patients. Concerning TGA, endogenous thrombin potential (ETP) was significantly decreased in patients on rivaroxaban as compared to those treated with apixaban (P < .003). A statistically significant, strong inverse correlation between apixaban plasma concentrations and ETP (P < .001) was observed. Apixaban significantly reduces ETP compared to controls, but to a lesser extent than rivaroxaban. Thrombin generation assay might provide additional information on apixaban exposure, which is required in order to individualize treatment especially for patients with a high bleeding risk. Our findings have to be further investigated in studies with larger sample sizes, in the entire range of apixaban exposure, with other direct oral anticoagulants, and in relation to clinical outcomes.

Improving access to medicines via the Health Impact Fund in India: a stakeholder analysis

Background: In India, 50–65% of the population face difficulties in accessing medicines. The Health Impact Fund (HIF) is a novel proposal whereby pharmaceutical companies would be paid based on the measured global health impact of their drugs. We conducted a key stakeholder analysis to explore access to medicines in India, acceptability of the HIF and potential barriers and facilitators at policy level.

Objectives: To conduct a stakeholder analysis of the HIF in India: to determine key stakeholder views regarding access to medicines in India; to evaluate acceptability of the HIF; and to assess potential barriers and facilitators to the HIF as a policy.

Methods: In New Delhi, we conducted semi-structured interviews. There was purposive recruitment of participants with snowball sampling. Transcribed data were analysed using stakeholder analysis frameworks and directed content analysis.

Results: Participation rate was 29% (14/49). 14 semi-structured interviews were conducted among stakeholders in New Delhi. All participants highlighted access to medicines as a problem in India. There were mixed views about the HIF in terms of relevance and scaleability. Stakeholders felt it should focus on diseases with limited or no market and potentially incorporate direct investment in research.

Conclusions: First, access to medicines is perceived to be a major problem in India by all stakeholders, but affordability is just one factor. Second, stakeholders despite considerable support for the idea of the HIF, there are major concerns about scaleability, generalisability and impact on access to medicines. Third, the HIF and other novel drug-related health policies can afford to be more radical, e.g. working outside the existing intellectual property rights regime, targeting generic as well as branded drugs, or extending to research and development. Further innovations in access to medicines must involve country-specific key stakeholders in order to increase the likelihood of their success.

Predictors of gastrointestinal bleeding among patients with atrial fibrillation after initiating dabigatran therapy

STUDY OBJECTIVES

To identify demographic and clinical risk factors associated with gastrointestinal (GI) bleeding among a large cohort of patients with atrial fibrillation (AF) who initiated dabigatran therapy for stroke prevention, and to describe patterns of subsequent anticoagulant use after occurrence of the GI bleeding event.

DESIGN

Retrospective cohort study.

DATA SOURCES

Large, nationwide United States commercial insurance database.

PATIENTS

A total of 21,033 patients with nonvalvular AF who initiated dabigatran between October 19, 2010, and December 31, 2012.

MEASUREMENTS AND MAIN RESULTS

We used multivariate Cox regression analysis to estimate the effect of baseline demographic and clinical characteristics on the probability of a GI bleeding event. Patterns of anticoagulation use after GI bleeding were also examined descriptively. Of the 21,033 patients receiving dabigatran, 446 (2.1%) experienced a GI bleed during follow-up. GI bleeding rates differed across many baseline characteristics. Male sex was associated with a lower risk (adjusted hazard ratio [aHR] 0.78, 95% confidence interval [CI] 0.64-0.95) of GI bleeding. Compared with patients younger than 55 years, those aged 55-64, 65-74, and 75 years or older yielded aHRs of 1.54 (95% CI 0.89-2.68), 2.72 (95% CI 1.59-4.65), and 4.52 (95% CI 2.68-7.64), respectively. Renal impairment (aHR 1.67, 95% CI 1.24-2.25), heart failure (aHR 1.25, 95% CI 1.01-1.56), alcohol abuse (aHR 2.57, 95%CI 1.52-4.35), previous Helicobacter pylori infection (aHR 4.75, 95% CI 1.93-11.68), antiplatelet therapy (aHR 1.49, 95% CI 1.19-1.88), and digoxin use (aHR 1.49, 95% CI 1.19-1.88) were also associated with an increased GI bleeding risk. Of the 446 patients who experienced a GI bleed, 193 (43.3%) restarted an anticoagulant, with most (65.8%) filling prescriptions for dabigatran; the mean time was 50.4 days until restarting any subsequent anticoagulant.

CONCLUSION

The risk of GI bleeding in patients receiving dabigatran is highly associated with increased age and cardiovascular, renal, and other comorbidities, even after adjusting for other factors. Fewer than 50% of patients restarted an anticoagulant after experiencing a GI bleed. Clinicians should continue to monitor for these risk factors or consider whether alternative therapies may be appropriate.

Critical appraisal of network meta-analyses evaluating the efficacy and safety of new oral anticoagulants in atrial fibrillation stroke prevention trials

OBJECTIVES

To critically appraise published network meta-analyses (NMAs) evaluating the efficacy or safety of the new oral anticogulants (NOACs) dabigatran, rivaroxaban, and apixaban for the prevention of stroke in patients with nonvalvular atrial fibrillation (AF).

METHODS

A systematic literature review was performed to identify the relevant NMAs using MEDLINE, EMBASE, Cochrane Library, Database of Abstracts of Reviews of Effects, and Health Technology Assessment. The synthesis studies were evaluated using the "Questionnaire to assess the relevance and credibility of the NMA."

RESULTS

Eleven NMAs evaluating NOACs among adults with nonvalvular AF were identified. Most NMAs included three large phase III randomized controlled trials, comparing NOACs to adjusted-dose warfarin (Randomized Evaluation of Long-Term Anticoagulation Therapy [RE-LY], Rivaroxaban Once Daily Oral Direct Factor Xa Inhibition Compared With Vitamin K Antagonism for Prevention of Stroke and Embolism Trial in Atrial Fibrillation [ROCKET-AF], and Apixaban for Reduction of Stroke and Other Thromboembolic Events in Atrial Fibrillation [ARISTOTLE]). The main differences identified related to potential treatment effect modifiers regarding the mean time spent in therapeutic range (TTR) in the warfarin arm, the risk of stroke or systemic embolism across the trials (mean CHADS2 score: C = congestive heart failure, H = hypertension, A = older than age 75 years, D = diabetes mellitus, S2 = prior stroke or history of transient ischemic attack) or primary versus secondary prevention, and type of populations used in the analysis. Kansal et al. [Kansal AR, Sharma M, Bradley-Kennedy C, et al. Dabigatran versus rivaroxaban for the prevention of stroke and systemic embolism in atrial fibrillation in Canada: comparative efficacy and cost-effectiveness. Thromb Haemost 2012;108:672-82] appropriately adjusted the ROCKET-AF TTR to match the RE-LY population on the basis of individual patient data. Meta-regressions are not expected to minimize confounding bias given limited data, whereas subgroup analyses had some impact on the point estimates for the treatment comparisons.

CONCLUSIONS

Results of the synthesis studies were generally comparable and suggested that the NOACs had similar efficacy, although some differences were identified depending on the outcome. The extent to which differences in the distribution of TTR, CHADS2 score, or primary versus secondary prevention biased the results remains unclear.

Class III antiarrhythmic drug dronedarone inhibits cardiac inwardly rectifying Kir2.1 channels through binding at residue E224

Dronedarone is a novel class III antiarrhythmic drug that is widely used in atrial fibrillation. It has been shown in native cardiomyocytes that dronedarone inhibits cardiac inwardly rectifying current IK1 at high concentrations, which may contribute both its antifibrillatory efficacy and its potential proarrhythmic side effects. However, the underlying mechanism has not been studied in further detail to date. In the mammalian heart, heterotetrameric assembly of Kir2.x channels is the molecular basis of IK1 current. Therefore, we studied the effects of dronedarone on wild-type and mutant Kir2.x channels in the Xenopus oocyte expression system. Dronedarone inhibited Kir2.1 currents but had no effect on Kir2.2 or Kir2.3 currents. Onset of block was slow but completely reversible upon washout. Blockade of Kir2.1 channels did not exhibit strong voltage dependence or frequency dependence. In a screening with different Kir2.1 mutants lacking specific binding sites within the cytoplasmic pore region, we found that residue E224 is essential for binding of dronedarone to Kir2.1 channels. In conclusion, direct block of Kir2.1 channel subunits by dronedarone through binding at E224 may underlie its inhibitory effects on cardiac IK1 current.

Novel oral anticoagulants for the prevention and treatment of thromboembolism

Over the last 5 years, new oral anticoagulant options, including dabigatran, rivaroxaban and apixaban, have become available. Prior to this, vitamin K antagonists were the sole oral anticoagulants, which have been in use for more than 60 years. These novel agents have been studied in a variety of patient populations, including atrial fibrillation, acute coronary syndrome, treatment of venous thromboembolism and thromboprophylaxis. Compared with standard care, these agents have largely been found to be noninferior or superior for efficacy end points, with similar or improved rates of bleeding. As a result, these agents have become attractive alternatives to vitamin K antagonists for the prevention and treatment of thromboembolic disease. This article provides a summary of clinical trial data to help clinicians determine which agent is most appropriate for a given patient.

Use of an interdisciplinary, participatory design approach to develop a usable patient self-assessment tool in atrial fibrillation

After identifying that significant care gaps exist within the management of atrial fibrillation (AF), a patient-focused tool was developed to help patients better assess and manage their AF. This tool aims to provide education and awareness regarding the management of symptoms and stroke risk associated with AF, while engaging patients to identify if their condition is optimally managed and to become involved in their own care. An interdisciplinary group of health care providers and designers worked together in a participatory design approach to develop the tool with input from patients. Usability testing was completed with 22 patients of varying demographics to represent the characteristics of the patient population. The findings from usability testing interviews were used to further improve and develop the tool to improve ease of use. A physician-facing tool was also developed to help to explain the tool and provide a brief summary of the 2012 Canadian Cardiovascular Society atrial fibrillation guidelines. By incorporating patient input and human-centered design with the knowledge, experience, and medical expertise of health care providers, we have used an approach in developing the tool that tries to more effectively meet patients' needs.