Antiplatelet therapy for preventing stroke in patients with non-valvular atrial fibrillation and no previous history of stroke or transient ischemic attacks

Association between Body Mass Index and Clinical Outcomes in Patients with Non-valvular Atrial Fibrillation Receiving Direct Oral Anticoagulants: A New Piece of Evidence on the Obesity Paradox from China

PURPOSE

We conducted a multicenter real-world study in China to assess the association between body mass index (BMI) and clinical outcomes in patients with atrial fibrillation (AF) taking direct oral anticoagulants (DOACs).

METHOD

This is a retrospective multicenter cohort study conducted in 15 centers in China. We collected demographic information through the hospital information system and obtained clinical events through follow-up visits to patients or relatives. Clinical outcomes include major, minor, total bleeding, thromboembolism, and all-cause death.

RESULT

A total of 6164 patients with non-valvular AF (NVAF) were included in this study. The incidence of major bleeding in patients with NVAF differed significantly by BMI category (P < 0.001), with 5.2% in the underweight group, 2.6% in the normal group, 1.4% in the overweight group, 1.1% in the obese I group, and 1.3% in the obese II group. There was no significant difference in minor, total bleeding, and thrombosis in the five groups (P = 0.493; P = 0.172; P = 0.663). All-cause death was significantly different among the five groups (P < 0.001), with 8.9% in the underweight group, 6.3% in the normal group, 4.8% in the overweight group, 2.2% in the obese I group, and 0.4% in the obese II group. High BMI was negatively associated with major bleeding (OR = 0.353, 95% CI 0.205-0.608), total bleeding (OR = 0.664, 95% CI 0.445-0.991), and all-cause death (OR = 0.370, 95% CI 0.260-0.527).

CONCLUSION

In patients with NVAF treated with DOACs, higher BMI was associated with lower major bleeding and better survival. BMI was a negative correlate of total bleeding, but not minor bleeding and thrombosis.

Effect of atrial fibrillation on outcomes after mechanical thrombectomy and long-term ischemic recurrence in patients with acute basilar artery occlusion

Introduction

According to the literature on anterior circulation, comorbid atrial fibrillation (AF) is not associated with a worse functional outcome, lower reperfusion rates, or higher rates of intracranial hemorrhage after mechanical thrombectomy (MT) compared to intravenous thrombolysis (IVT) or treatment with supportive care. However, data are limited for the effect of comorbid AF on procedural and clinical outcomes of acute basilar artery occlusion (ABAO) after MT. This study aimed to investigate the effect of atrial fibrillation on outcomes after MT and long-term ischemic recurrence in patients with ABAO.

Methods

We performed a registered study of the Endovascular Treatment for Acute Basilar Artery Occlusion Study (BASILAR, which is registered in the Chinese Clinical Trial Registry, http://www.chictr.org.cn; ChiCTR1800014759) from January 2014 to May 2019, which included 647 patients who underwent MT for ABAO, 136 of whom had comorbid AF. Prospectively defined baseline characteristics, procedural outcomes, and clinical outcomes were reported and compared.

Results

On multivariate analysis, AF predicted a shorter puncture-to-recanalization time, higher first-pass effect rate, and lower incidence of angioplasty and/or stenting (p < 0.01). AF had no effect on intracranial hemorrhage incidence [adjusted odds ratio (aOR), 1.093; 95% confidence interval (CI), 0.451–2.652], 90-day functional outcomes (adjusted common odds ratio, 0.915; 95% CI, 0.588–1.424), or mortality (aOR, 0.851; 95% CI, 0.491–1.475) after MT. The main findings were robust in the subgroup and 1-year follow-up analyses. Comorbid AF was the remaining predictor of ischemic recurrence (aOR, 4.076; 95% CI, 1.137–14.612).

Conclusions

The study revealed no significant difference in the safety and efficacy of MT for ABAO regardless of whether patients had comorbid AF. However, a higher proportion of patients with AF experienced ischemic recurrence within 1 year after MT.

In-hospital prognosis of first-ever noncardiogenic ischemic stroke in patients with and without indication for prestroke antiplatelet therapy: Chinese Stroke Center Alliance

Background

It is unknown about the influence of prestroke antiplatelet use on early outcomes in patients with and without the indication. We aimed to evaluate the in-hospital prognosis of first-ever noncardiogenic ischemic stroke patients with and without indications of antiplatelet use for primary prevention.

Methods

This was a retrospective, observational study based on a prospective hospital-based registry (Chinese Stroke Center Alliance). Using the data with 436,660 first-ever noncardiogenic acute ischemic strokes recorded from Aug 1, 2015, to July 31, 2019, from 1,453 hospitals in China, we examined the associations between the indication for prestroke antiplatelet use and in-hospital clinical outcomes.

Results

Among 436,660 first-ever noncardiogenic ischemic stroke patients, 42,409 patients (9.7%) had a documented previous vascular indication and 394,251 (90.3%) did not. Compared to those without, patients with the indication were associated with increased prevalence of in-hospital morbid conditions, including stroke severity (OR 2.71; 95% CI: 2.62–2.81; P<0.0001), length of stay >14 days (OR 1.16; 95% CI: 1.13–1.19; P<0.0001), mortality (OR 2.20; 95% CI: 1.96–2.46, P<0.0001), and recurrence of ischemic stroke and transient ischemic attack (TIA) (OR 1.5; 95% CI: 1.43–1.59, P<0.0001). Among patients without indication, prestroke antiplatelet use was associated with lower mortality (OR 0.73, 95% CI: 0.56–0.96; P=0.0221); while among patients with indication, those receiving prestroke antiplatelet had lower odds ratios in stroke severity (P<0.0001) and disability (P=0.0003) than those who not.

Conclusions

Patients with indications of prestroke antiplatelet use were more likely to have unfavorable outcomes than those without. Prestroke antiplatelet might be associated with lower mortality, less disability, and less stroke severity in certain population groups. Future studies to improve risk prediction rules are needed to guide effective primary prevention for ischemic stroke.

Efficacy and Safety of Direct Oral Anticoagulants vs Warfarin in Patients with Chronic Kidney Disease and Dialysis Patients: A Systematic Review and Meta-Analysis

BACKGROUND AND OBJECTIVE: Systematic reviews and meta-analyses of direct oral anticoagulants (DOACs) for patients with chronic kidney disease (CKD) or dialysis patients are lacking. We aimed to compare the efficacy and safety of DOACs and warfarin in patients with CKD requiring anticoagulation therapy.

METHODS

We performed a systematic review and meta-analysis of six randomized controlled trials and 19 observational studies, with the inclusion criteria being a comparative study between DOACs and warfarin in patients with CKD or dialysis patients from database inception until August 2020. The efficacy outcomes were stroke, systemic embolism (SE), or venous thromboembolism (VTE), and the safety outcome was major bleeding.

RESULTS

Compared with warfarin, DOACs significantly reduced the risk of stroke/SE/VTE by 22% (hazard ratio [HR] = 0.78, 95% confidence interval [CI] 0.64-0.95) and major bleeding by 17% (HR = 0.83, 95% CI 0.71-0.97). On comparing factor Xa inhibitors and dabigatran with warfarin separately, factor Xa inhibitors significantly reduced the risk of stroke/SE/VTE (HR = 0.78, 95% CI 0.62-0.98) and major bleeding (HR = 0.76, 95% CI 0.64-0.91) overall in patients. Comparing each DOACs with warfarin separately, apixaban was associated with a significantly better risk reduction of stroke/SE/VTE (25% risk reduction) and major bleeding (35% risk reduction) than warfarin. Compared with warfarin, DOACs significantly reduced the risk of stroke, SE, or VTE by 19% (HR = 0.81, 95% CI 0.68-0.97) in patients with CKD stage 3 and significantly lowered the risk of major bleeding by 31% (HR = 0.69, 95% CI 0.56-0.85) in patients with CKD stages 4-5.

CONCLUSIONS

In pooled, analyzed randomized controlled trials and observational studies, DOACs were associated with better efficacy in early CKD, as well as similar efficacy and safety outcomes to warfarin in patients with CKD stages 4-5 or dialysis patients. The results of patients with CKD stages 4-5 and dialysis patients were from observational studies. Well-designed randomized controlled trials focused on DOAC use in patients with CKD and dialysis patients are needed. PROSPERO register number: CRD42020150599, 6 February, 2020.

A meta-epidemiological study of subgroup analyses in cochrane systematic reviews of atrial fibrillation

BACKGROUND

Information on subgroup assessments in systematic reviews (SR) of atrial fibrillation (AF) is limited. This review aims to describe subgroup analyses in AF SRs to inform the design of SRs and randomized trials as well as clinical practice.

METHODS

We conducted a cross sectional meta-epidemiological study of Cochrane AF reviews by searching AF (including variants) in the title, abstract, or keyword field without date or language restrictions (Issue 9; September 2018). Two reviewers independently extracted study characteristics to summarize frequency of subgroups pre-specified and conducted and report credibility of subgroup effects claimed.

RESULTS

Of 39 Cochrane reviews identified, 17 met inclusion criteria (including 168 reports of 127 randomized trials) and the majority (16; 94.1%) conducted meta-analysis of outcomes. Most (13; 76.5%) planned pre-specified subgroup analyses; 7 of which (41.2%) conducted subgroups. In these 7 reviews, 56 subgroups were planned, 17 (30.4%) conducted and 6 (10.7%) yielded subgroup effects. Variables such as co-morbid disease, stroke risk factors, prior stroke/transient ischemic attack, age, race, and sex represented 44% (24 subgroups) of all planned subgroups (8 conducted; 14.3%); however, information on covariate selection was lacking. Overall, more subgroups were planned than conducted (mean difference (95% CI) 2.3 (1.2-3.5, p < 0.001)). Of all subgroups conducted, anticoagulant characteristics comprised a third of all subgroup effects (n = 5, 35.7%). The credibility of subgroups identified (n = 14) was assessed and less than half (43%) represented one of a small number of pre-specified hypothesis and rarely were effects seen within studies (7%). Of 5 reviews that reported subgroup effects, only 3 discussed subgroup effects as part of the overall conclusions; none discussed credibility of subgroup effects.

CONCLUSIONS

This meta-epidemiological review of a subset of Cochrane AF reviews suggests that planning and reporting of subgroup analyses in AF reviews can be improved to better inform clinical management. Most pre-specified subgroup analyses were not performed, important variables (such as stroke, bleeding risk, and other comorbidities) were rarely examined and credibility of subgroup effects claimed was low. Future reviews should aim to identify important subgroups in their protocols and use recommended approaches to test subgroup effects in order to better support clinical decision-making.

The REstart or STop Antithrombotics Randomised Trial (RESTART) after stroke due to intracerebral haemorrhage: study protocol for a randomised controlled trial

Background

For adults surviving stroke due to spontaneous (non-traumatic) intracerebral haemorrhage (ICH) who had taken an antithrombotic (i.e. anticoagulant or antiplatelet) drug for the prevention of vaso-occlusive disease before the ICH, it is unclear whether starting antiplatelet drugs results in an increase in the risk of recurrent ICH or a beneficial net reduction of all serious vascular events compared to avoiding antiplatelet drugs.

Methods/design

The REstart or STop Antithrombotics Randomised Trial (RESTART) is an investigator-led, randomised, open, assessor-blind, parallel-group, randomised trial comparing starting versus avoiding antiplatelet drugs for adults surviving antithrombotic-associated ICH at 122 hospital sites in the United Kingdom. RESTART uses a central, web-based randomisation system using a minimisation algorithm, with 1:1 treatment allocation to which central research staff are masked. Central follow-up includes annual postal or telephone questionnaires to participants and their general (family) practitioners, with local provision of information about adverse events and outcome events. The primary outcome is recurrent symptomatic ICH. The secondary outcomes are: symptomatic haemorrhagic events; symptomatic vaso-occlusive events; symptomatic stroke of uncertain type; other fatal events; modified Rankin Scale score; adherence to antiplatelet drug(s). The magnetic resonance imaging (MRI) sub-study involves the conduct of brain MRI according to a standardised imaging protocol before randomisation to investigate heterogeneity of treatment effect according to the presence of brain microbleeds. Recruitment began on 22 May 2013. The target sample size is at least 720 participants in the main trial (at least 550 in the MRI sub-study).

Discussion

Final results of RESTART will be analysed and disseminated in 2019.

Trial registration

ISRCTN71907627 (www.isrctn.com/ISRCTN71907627). Prospectively registered on 25 April 2013.

Electronic supplementary material

The online version of this article (10.1186/s13063-018-2542-6) contains supplementary material, which is available to authorized users.

Anticoagulation for atrial fibrillation after intracranial hemorrhage: A systematic review

Background

We summarize the existing evidence on the potential benefit of oral anticoagulation (OAC) in intracerebral hemorrhage (ICH) survivors with nonvalvular atrial fibrillation (NVAF).

Methods

Systematic review of the literature to address the following issues: (1) prevalence of NVAF in ICH survivors, (2) current prescription of OAC, (3) factors associated with resumption of OAC, (4) risk of ischemic stroke (IS) and recurrent ICH, and (5) ideal timing for restarting OAC in ICH survivors with NVAF.

Results

After screening 547 articles, 26 were included in the review. Only 3 focused specifically on patients with ICH as primary event, NVAF as indication for OAC, and recurrent ICH and IS as primary endpoints. In addition, 19 letters to the editor/reviews/editorials/experts' surveys/experts' opinion were used for discussion purposes.

Conclusions

NVAF is highly prevalent among ICH survivors. The risks of IS, recurrent ICH, and mortality are heightened in this group. Most published data show a net benefit in terms of IS prevention and mortality when anticoagulation is restarted. However, those studies are observational and mostly retrospective, therefore selection bias may play a major role in the results observed in these cohorts. Only randomized controlled trials, either pragmatic or explanatory, can provide more conclusive answers for this important clinical question.

Trend of Prevalence of Atrial Fibrillation and use of Oral Anticoagulation Therapy in Patients With Atrial Fibrillation in South Korea (2002-2013)

BACKGROUND

This study examined the annual prevalence of atrial fibrillation (AF) and its associated comorbidities, as well as the prevalence of warfarin therapy in South Korean patients with AF.

METHODS

The National Health Insurance Service-National Sample Cohort database was searched for subjects aged ≥30 years diagnosed with AF from 2002-2013. The prevalence of AF was analyzed by sex and age, as was the current status of warfarin therapy in AF patients according to CHA₂DS₂-VASc score and comorbidities.

RESULTS

The age-standardized prevalence of AF in men and women was 0.15% and 0.14%, respectively, in 2002, increasing to 0.54% and 0.39%, respectively, in 2013. In 2013, the prevalence of AF in men and women aged 30-39 years was 0.08% and 0.03%, respectively, increasing to 2.35% and 1.71%, respectively, in those in aged ≥60 years. During 2002-2013, the prevalence of AF in men significantly increased among subjects aged ≥30 years and increased in women aged ≥60 years. The age-standardized prevalence of hypertension and diabetes mellitus among AF patients were markedly increased during 2002-2013. Of these AF patients, 86.1% had a CHA₂DS₂-VASc score of ≥2; however, only 39.1% of these were receiving warfarin.

CONCLUSIONS

The age-standardized prevalence of AF increased 2.89-fold over the 12-year study period. The total number of patients with AF in South Korea has been drastically increasing, due to not only aging society but also increasing age-specific prevalence of AF, especially in middle-aged and elderly individuals. The rate of warfarin therapy increased slightly over the study period but remains low.

Effectiveness and patient safety of platelet aggregation inhibitors in the prevention of cardiovascular disease and ischemic stroke in older adults - a systematic review

BACKGROUND

Platelet aggregation inhibitors (PAI) are among the most frequently prescribed drugs in older people, though evidence about risks and benefits of their use in older adults is scarce. The objectives of this systematic review are firstly to identify the risks and benefits of their use in the prevention and treatment of vascular events in older adults, and secondly to develop recommendations on discontinuing PAI in this population if risks outweigh benefits.

METHODS

Staged systematic review consisting of three searches. Searches 1 and 2 identified systematic reviews and meta-analyses. Search 3 included controlled intervention and observational studies from review-articles not included in searches 1 and 2. All articles were assessed by two independent reviewers regarding the type of study, age of participants, type of intervention, and clinically relevant outcomes. After data extraction and quality appraisal we developed recommendations to stop the prescribing of specific drugs in older adults following the Grading of Recommendations Assessment Development and Evaluation (GRADE) methodology.

RESULTS

Overall, 2385 records were screened leading to an inclusion of 35 articles reporting on 22 systematic reviews and meta-analyses, 11 randomised controlled trials, and two observational studies. Mean ages ranged from 57.0 to 84.6 years. Ten studies included a subgroup analysis by age. Overall, based on the evaluated evidence, three recommendations were formulated. First, the use of acetylsalicylic acid (ASA) for primary prevention of cardiovascular disease (CVD) in older people cannot be recommended due to an uncertainty in the risk-benefit ratio (weak recommendation; low quality of evidence). Secondly, the combination of ASA and clopidogrel in patients without specific indications should be avoided (strong recommendation; moderate quality of evidence). Lastly, to improve the effectiveness and reduce the risks of stroke prevention therapy in older people with atrial fibrillation (AF) and a CHA₂DS₂-VASc score of ≥ 2, the use of ASA for the primary prevention of stroke should be discontinued in preference for the use of oral anticoagulants (weak recommendation; low quality of evidence).

CONCLUSIONS

The use of ASA for the primary prevention of CVD and the combination therapy of ASA and clopidogrel for the secondary prevention of vascular events in older people may not be justified. The use of oral anticoagulants instead of ASA in older people with atrial fibrillation may be recommended. Further high quality studies with older adults are needed.

Improving stroke prevention therapy for patients with atrial fibrillation in primary care: protocol for a pragmatic, cluster-randomized trial

Background

The prevalence of atrial fibrillation (AF) is growing as the population ages, and at least 15% of ischemic strokes are attributed to AF. However, many high-risk AF patients are not offered guideline-recommended stroke prevention therapy due to a variety of system, provider, and patient-level barriers.

Methods

We will conduct a pragmatic, cluster-randomized controlled trial randomizing primary care clinics to test a “toolkit” of quality improvement interventions in primary care. In keeping with the recommendations of the chronic care model to simultaneously activate patients and facilitate proactive care by providers, the toolkit includes provider-focused strategies (education, audit and feedback, electronic decision support, and reminders) plus patient-directed strategies (educational letters and reminders). The trial will include two feedback cycles at baseline and approximately 6 months and a final data collection at approximately 12 months. The study will be powered to show a difference of 10% in the primary outcome of proportion of patients receiving guideline-recommended stroke prevention therapy. Analysis will follow the intention-to-treat principle and will be blind to treatment allocation. Unit of analysis will be the patient; models will use generalized estimating equations to account for clustering at the clinical level.

Discussion

Stroke prevention therapy using anticoagulation in patients with AF is known to reduce strokes by two thirds or more in clinical trials, but most studies indicate under-use of this treatment in real-world practice. If the toolkit successfully improves care for patients with AF, stakeholders will be engaged to facilitate broader application to maximize the potential to improve patient outcomes. The intervention toolkit tested in this project could also provide a model to improve quality of care for other chronic cardiovascular conditions managed in primary care.

Trial registration

ClinicalTrials.gov (NCT01927445). Registered August 14, 2014 at https://clinicaltrials.gov/.

Electronic supplementary material

The online version of this article (doi:10.1186/s13012-016-0523-2) contains supplementary material, which is available to authorized users.

Antiplatelet versus anticoagulation treatment for patients with heart failure in sinus rhythm

BACKGROUND

Morbidity in patients with chronic heart failure is high, and this predisposes them to thrombotic complications, including stroke and thromboembolism, which in turn contribute to high mortality. Oral anticoagulants (e.g. warfarin) and antiplatelet agents (e.g. aspirin) are the principle oral antithrombotic agents. Many heart failure patients with sinus rhythm take aspirin because coronary artery disease is the leading cause of heart failure. Oral anticoagulants have become a standard in the management of heart failure with atrial fibrillation. However, a question remains regarding the appropriateness of oral anticoagulants in heart failure with sinus rhythm. This update of a review previously published in 2012 aims to address this question.

OBJECTIVES

To assess the effects of oral anticoagulant therapy versus antiplatelet agents for all-cause mortality, non-fatal cardiovascular events and risk of major bleeding in adults with heart failure (either with reduced or preserved ejection fraction) who are in sinus rhythm.

SEARCH METHODS

We updated the searches in September 2015 on CENTRAL (The Cochrane Library), MEDLINE and Embase. We searched reference lists of papers and abstracts from cardiology meetings and contacted study authors for further information. We did not apply any language restrictions. Additionally, we searched two clinical trials registers: ClinicalTrials.gov (www.ClinicalTrials.gov) and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) Search Portal apps.who.int/trialsearch/) (searched in July 2016).

SELECTION CRITERIA

We included randomised controlled trials comparing antiplatelet therapy versus oral anticoagulation in adults with chronic heart failure in sinus rhythm. Treatment had to last at least one month. We compared orally administered antiplatelet agents (aspirin, ticlopidine, clopidogrel, prasugrel, ticagrelor, dipyridamole) versus anticoagulant agents (coumarins, warfarin, non-vitamin K oral anticoagulants).

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and assessed the risks and benefits of antithrombotic versus antiplatelet therapy using relative measures of effects, such as risk ratios (RR), accompanied with 95% confidence intervals (CI). The data extracted included data relating to the study design, patient characteristics, study eligibility, quality, and outcomes. We used GRADE criteria to assess the quality of the evidence.

MAIN RESULTS

This update identified one additional study for inclusion, adding data for 2305 participants. This addition more than doubled the overall number of patients eligible for the review. In total, we included four randomised controlled trials (RCTs) with a total of 4187 eligible participants. All studies compared warfarin with aspirin. One RCT additionally compared warfarin with clopidogrel. All included RCTs studied patients with heart failure with reduced ejection fraction.Analysis of all outcomes for warfarin versus aspirin was based on 3663 patients from four RCTs. All-cause mortality was similar for warfarin and aspirin (RR 1.00, 95% CI 0.89 to 1.13; 4 studies; 3663 participants; moderate quality evidence). Oral anticoagulation was associated with a reduction in non-fatal cardiovascular events, which included non-fatal stroke, myocardial infarction, pulmonary embolism, peripheral arterial embolism (RR 0.79, 95% CI 0.63 to 1.00; 4 studies; 3663 participants; moderate quality evidence). The rate of major bleeding events was twice as high in the warfarin groups (RR 2.00, 95% CI 1.44 to 2.78; 4 studies; 3663 participants; moderate quality evidence). We generally considered the risk of bias of the included studies to be low.Analysis of warfarin versus clopidogrel was based on a single RCT (N = 1064). All-cause mortality was similar for warfarin and clopidogrel (RR 0.93, 95% CI 0.72 to 1.21; 1 study; 1064 participants; low quality evidence). There were similar rates of non-fatal cardiovascular events (RR 0.85, 95% CI 0.50 to 1.45; 1 study; 1064 participants; low quality evidence). The rate of major bleeding events was 2.5 times higher in the warfarin group (RR 2.47, 95% CI 1.24 to 4.91; 1 study; 1064 participants; low quality evidence). Risk of bias for this study can be summarised as low.

AUTHORS' CONCLUSIONS

There is evidence from RCTs to suggest that neither oral anticoagulation with warfarin or platelet inhibition with aspirin is better for mortality in systolic heart failure with sinus rhythm (high quality of the evidence for all-cause mortality and moderate quality of the evidence for non-fatal cardiovascular events and major bleeding events). Treatment with warfarin was associated with a 20% reduction in non-fatal cardiovascular events but a twofold higher risk of major bleeding complications (high quality of the evidence). We saw a similar pattern of results for the warfarin versus clopidogrel comparison (low quality of the evidence). At present, there are no data on the role of oral anticoagulation versus antiplatelet agents in heart failure with preserved ejection fraction with sinus rhythm. Also, there were no data from RCTs on the utility of non-vitamin K antagonist oral anticoagulants compared to antiplatelet agents in heart failure with sinus rhythm.

Apixaban versus Antiplatelet drugs or no antithrombotic drugs after anticoagulation-associated intraCerebral HaEmorrhage in patients with Atrial Fibrillation (APACHE-AF): study protocol for a randomised controlled trial

BACKGROUND

There is a marked lack of evidence on the optimal prevention of ischaemic stroke and other thromboembolic events in patients with non-valvular atrial fibrillation and a recent intracerebral haemorrhage during treatment with oral anticoagulation. These patients are currently treated with oral anticoagulants, antiplatelet drugs, or no antithrombotic treatment, depending on personal and institutional preferences. Compared with warfarin, the direct oral anticoagulant apixaban reduces the risk of stroke or systemic embolism, intracranial haemorrhage, and case fatality in patients with atrial fibrillation. Compared with aspirin, apixaban reduces the risk of stroke or systemic embolism in patients with atrial fibrillation, and has a similar risk of intracerebral haemorrhage. Novel oral anticoagulants have not been evaluated in patients with atrial fibrillation and a recent intracerebral haemorrhage. To inform a phase III trial, the phase II Apixaban versus Antiplatelet drugs or no antithrombotic drugs after anticoagulation-associated intraCerebral HaEmorrhage in patients with Atrial Fibrillation (APACHE-AF) trial aims to obtain estimates of the rates of vascular death or non-fatal stroke in patients with atrial fibrillation and a recent anticoagulation-associated intracerebral haemorrhage treated with apixaban and in those in whom oral anticoagulation is avoided.

METHODS/DESIGN

APACHE-AF is a phase II, multicentre, open-label, parallel-group, randomised clinical trial with masked outcome assessment. One hundred adults with a history of atrial fibrillation and a recent intracerebral haemorrhage during treatment with anticoagulation in whom clinical equipoise exists on the optimal stroke prevention strategy will be enrolled in 14 hospitals in The Netherlands. These patients will be randomly assigned in a 1:1 ratio to either apixaban or to avoiding oral anticoagulation. Patients in the control group may be treated with antiplatelet drugs at the discretion of the treating physician. The primary outcome is the composite of vascular death or non-fatal stroke during follow-up. We aim to include 100 patients in 2.5 years. All patients will be followed-up for the duration of the study, but at least for 1 year. Recruitment commenced in September 2014 and is ongoing. This trial is funded by the Dutch Heart Foundation (2012 T077) and ZonMW (015008048).

TRIAL REGISTRATION

NTR4526 (16 April 2014).

Antiplatelet Therapy During PCI for Patients with Stable Angina and Atrial Fibrillation

The pharmacological treatment options for anticoagulation in patients with atrial fibrillation (Afib) have increased with the introduction of novel oral anticoagulants, compared with earlier times, when vitamin K antagonist was the drug of choice. As they age, many Afib patients require percutaneous coronary intervention (PCI), necessitating antiplatelet medication in addition to anticoagulation therapy. Choosing the appropriate combination and duration of anticoagulation and antiplatelet therapies may be challenging in stable coronary artery disease (CAD) and even more complicated during and after coronary intervention with the introduction of additional antithrombotic drugs. In this article, we review the scientific basis for the recent guidelines for anticoagulation and antithrombotic therapy in patients with Afib and stable CAD before, during, and after elective PCI.

Anticoagulation in Patients Aged ≥75 years with Atrial Fibrillation: Role of Novel Oral Anticoagulants

Atrial fibrillation (AF) is an important cause of preventable, disabling stroke and is increasingly prevalent with advancing age. As life expectancies increase around the world, AF-related stroke is a growing global public health concern. Most AF patients are elderly (≥75 years old) and increasing age is a consistent independent risk factor for AF-associated stroke. Warfarin anticoagulation is highly effective for stroke prevention in AF patients, but is underutilized especially in the elderly. Although elderly patients are at increased risk of hemorrhage with oral anticoagulants, the benefit for ischemic stroke reduction exceeds the risk of hemorrhage for most elderly patients. Consequently, age alone should not be considered a contraindication for anticoagulation. Novel oral anticoagulants such as dabigatran, rivaroxaban and apixaban are at least as effective as warfarin in preventing strokes in patients with AF. Relative to warfarin, these novel agents reduce the risk of intracranial hemorrhage, the most devastating complication of anticoagulation therapy in elderly AF patients. The novel oral anticoagulants are especially appealing for stroke prevention in elderly patients with AF.

Novel anticoagulants in atrial fibrillation stroke prevention

This review article evaluates novel oral anticoagulants in comparison with warfarin for thromboembolism prophylaxis in patients with atrial fibrillation (AF). AF is the most frequently diagnosed arrhythmia in the United States. The most serious side effect of AF is stroke. Warfarin has several decades of proven efficacy in AF-related stroke prevention but the drug's numerous drawbacks make its implementation difficult for practitioners and patients. The difficulties of warfarin have prompted the development of alternative anticoagulants for AF-related stroke prevention with better efficacy, safety, and convenience. The oral direct thrombin inhibitor, dabigatran, and the oral factor Xa inhibitors, rivaroxaban and apixaban, have been evaluated in a large phase III trial. Dabigatran, rivaroxaban and apixaban were shown to be noninferior compared with warfarin in the prevention of stroke. Dabigatran and apixaban were found to be statistically superior to warfarin. All three may also have a better safety profile than warfarin. In conclusion, novel anticoagulants have a different pharmacologic profile compared with warfarin that may eliminate many of the treatment inconveniences. Practitioners must also be aware of the disadvantages these new drugs possess when choosing a management strategy for their patients. Drug selection may become clearer as these new drugs are used more extensively.

Prevention of cardioembolic stroke

Cardiac causes of ischemic stroke lead to severe neurological deficits from large intracranial artery occlusion compared to small vessel ischemic stroke. The most common cause of cardioembolic stroke is atrial fibrillation (AF), which has an increasing incidence with age. AF stroke trials demonstrate that anti-coagulation is superior to anti-platelet therapy in terms of ischemic stroke prevention. Recently, warfarin was compared with dabigatran, an oral, direct thrombin inhibitor, and was found to be at least equally effective in reducing ischemic stroke with less intracranial bleeding risk. Future research is investigating other direct thrombin inhibitors as potential alternatives to warfarin, which has a narrow therapeutic index, requires frequent blood monitoring, has multiple drug interactions, and a higher rate of intracranial bleeding. Other causes of cardioembolic stroke include myocardial infarction, left ventricular thrombus, reduced ejection fraction, valvular abnormalities, and endocarditis. Patent foramen ovale is a common finding on echocardiograms in patients with and without stroke (up to 20% of the population), and it is a controversial source of cryptogenic stroke. The best way to prevent cardioembolic stroke remains early detection and treatment of AF, and treating the underlying stroke mechanism. Cardiac magnetic resonance imaging is an emerging technology and reveals some sources of cardiac embolism missed by echocardiography, and might provide an additional diagnostic tool in investigating cardioembolic stroke.

Anticoagulants for preventing recurrence following presumed non-cardioembolic ischaemic stroke or transient ischaemic attack

BACKGROUND

After a first ischaemic stroke, further vascular events due to thromboembolism are common and often fatal. Anticoagulants could potentially reduce the risk of such events, but any benefits could be offset by an increased risk of fatal or disabling haemorrhages.

OBJECTIVES

To assess the effect of prolonged anticoagulant therapy compared with placebo or open control following presumed non-cardioembolic ischaemic stroke or transient ischaemic attack.

SEARCH STRATEGY

We searched the Cochrane Stroke Group Trials Register in May 2008. In June 2008 we searched three online trial registers, used Web of Science Cited Reference Search to identify new citations of previously included studies, contacted a pharmaceutical company, and also contacted authors for additional information on included trials.

SELECTION CRITERIA

Randomised and quasi-randomised trials comparing at least one month of anticoagulant therapy with control in people with previous, presumed non-cardioembolic, ischaemic stroke or transient ischaemic attack.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion, assessed trial quality and extracted the data.

MAIN RESULTS

Eleven trials involving 2487 participants were included. The quality of the nine trials which predated routine computerised tomography (CT) scanning and the use of the International Normalised Ratio to monitor anticoagulation was poor. There was no evidence of an effect of anticoagulant therapy on either the odds of death or dependency (two trials, odds ratio (OR) 0.83, 95% confidence interval (CI) 0.52 to 1.34) or of 'non-fatal stroke, myocardial infarction, or vascular death' (four trials, OR 0.96, 95% CI 0.68 to 1.37). Death from any cause (OR 0.95, 95% CI 0.73 to 1.24) and death from vascular causes (OR 0.86, 95% CI 0.66 to 1.13) were not significantly different between treatment and control. The inclusion of two recently completed trials did not alter these conclusions. There was no evidence of an effect of anticoagulant therapy on the risk of recurrent ischaemic stroke (OR 0.85, 95% CI 0.66 to 1.09). However, anticoagulants increased fatal intracranial haemorrhage (OR 2.54, 95% CI 1.19 to 5.45), and major extracranial haemorrhage (OR 3.43, 95% CI 1.94 to 6.08). This is equivalent to anticoagulant therapy causing about 11 additional fatal intracranial haemorrhages and 25 additional major extracranial haemorrhages per year for every 1000 patients given anticoagulant therapy.

AUTHORS' CONCLUSIONS

Compared with control, there was no evidence of benefit from long-term anticoagulant therapy in people with presumed non-cardioembolic ischaemic stroke or transient ischaemic attack, but there was a significant bleeding risk.

Drug Insight: antithrombotic therapy after percutaneous coronary intervention in patients with an indication for anticoagulation

Antiplatelet therapy with aspirin and clopidogrel is standard care following revascularization by percutaneous coronary intervention with stent insertion. This so-called dual therapy is recommended for up to 4 weeks after intervention for bare-metal stents and for 6-12 months after intervention for drug-eluting stents. Although it is estimated that 5% of patients undergoing percutaneous coronary intervention require long-term anticoagulation because of an underlying chronic medical condition, continuing treatment with triple therapy (warfarin, aspirin and clopidogrel) increases the risk of bleeding. In most patients triple antithrombotic therapy seems justified for a short period of time. In some patients, however, a more considered judgment based on absolute need for triple therapy, risk of bleeding and risk of stent thrombosis is required, but the optimum antithrombotic treatment for these patients who require long-term anticoagulation has not been defined. This Review summarizes the existing literature concerning antithrombotic therapy and makes recommendations for initiation and duration of triple therapy in the small proportion of patients already receiving anticoagulant therapy who require percutaneous coronary intervention.

Pharmacogenetics of warfarin: current status and future challenges

Warfarin is an anticoagulant that is difficult to use because of the wide variation in dose required to achieve a therapeutic effect, and the risk of serious bleeding. Warfarin acts by interfering with the recycling of vitamin K in the liver, which leads to reduced activation of several clotting factors. Thirty genes that may be involved in the biotransformation and mode of action of warfarin are discussed in this review. The most important genes affecting the pharmacokinetic and pharmacodynamic parameters of warfarin are CYP2C9 (cytochrome P(450) 2C9) and VKORC1 (vitamin K epoxide reductase complex subunit 1). These two genes, together with environmental factors, partly explain the interindividual variation in warfarin dose requirements. Large ongoing studies of genes involved in the actions of warfarin, together with prospective assessment of environmental factors, will undoubtedly increase the capacity to accurately predict warfarin dose. Implementation of pre-prescription genotyping and individualized warfarin therapy represents an opportunity to minimize the risk of haemorrhage without compromising effectiveness.