Dataset Information

Phenotypes of atrial fibrillation diagnosed before-versus-after ischaemic stroke and TIA: study protocol for a systematic review and meta-analysis.

ABSTRACT:

Introduction

The underlying pathophysiology of atrial fibrillation (AF) detected after stroke (AFDAS) is relatively unknown. Preliminary evidence suggests AFDAS has a lower prevalence of cardiovascular comorbidities and higher incidence of insular cortex involvement than AF known to exist before stroke occurrence (KAF). This favours a neurogenic AF substrate (autonomic dysregulation) in which the presence of underlying heart disease is not necessary for AF to occur. The main objective of this systematic review and meta-analysis is to compare the prevalence of cardiovascular comorbidities and echocardiographic abnormalities in patients with AFDAS, KAF and no AF (NAF). Secondary objectives are to compare the proportion with insular cortex involvement, stroke recurrence and death in the three rhythm groups.

Methods and analysis

We will perform a systematic review including cross-sectional, case-control, cohort studies and clinical trials involving ≥18 years patients, with ischaemic stroke or transient ischaemic attack published between inception and 31 December 2020 in any language, and reporting the proportion of patients with AFDAS, KAF and NAF. We will search PubMed, EMBASE and Scopus by applying predefined search terms. Two reviewers will independently screen titles and abstracts and retrieve full texts, extract data in a predesigned form, and assess the risk of bias. We will perform a meta-analysis of all included studies and we will report the results of the main outcome as proportions. We will report results of secondary outcomes as risk ORs. We will estimate heterogeneity across studies by using t², Q and I² measures. We will use funnel plots, Rosenthal's Fail-Safe N and Egger's regression intercept to assess publication bias.

Ethics and dissemination

This study will be based on published data and does therefore not require ethical clearance. The results will be published in peer-reviewed journals.

Prospero registration number

CRD42020202622.

SUBMITTER: Jimenez-Ruiz A

PROVIDER: S-EPMC8256738 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:BackgroundAbout 13-26% of all acute ischaemic strokes are related to non-valvular atrial fibrillation, the most common cardiac arrhythmia globally. Deciding when to initiate oral anticoagulation in patients with non-valvular atrial fibrillation is a longstanding, common, and unresolved clinical challenge. Although the risk of early recurrent ischaemic stroke is high in this population, early oral anticoagulation is suspected to increase the risk of potentially harmful intracranial haemorrhage, including haemorrhagic transformation of the infarct. This assumption, and current treatment guidelines, are based on historical, mostly observational data from patients with ischaemic stroke and atrial fibrillation treated with heparins, heparinoids, or vitamin K antagonists (VKAs) to prevent recurrent ischaemic stroke. Randomised controlled trials have subsequently shown that direct oral anticoagulants (DOACs; ie, apixaban, dabigatran, edoxaban, and rivaroxaban) are at least as effective as VKAs in primary and secondary prevention of atrial fibrillation-related ischaemic stroke, with around half the risk of intracranial haemorrhage. However, none of these DOAC trials included patients who had experienced ischaemic stroke recently (within the first few weeks). Clinicians therefore remain uncertain regarding when to commence DOAC administration after acute ischaemic stroke in patients with atrial fibrillation.Recent developmentsProspective observational studies and two small randomised trials have investigated the risks and benefits of early DOAC-administration initiation (most with a median delay of 3-5 days) in mild-to-moderate atrial fibrillation-associated ischaemic stroke. These studies reported that early DOAC treatment was associated with a low frequency of clinically symptomatic intracranial haemorrhage or surrogate haemorrhagic lesions on MRI scans, whereas later DOAC-administration initiation (ie, >7 days or >14 days after index stroke) was associated with an increased frequency of recurrent ischaemic stroke. WHERE NEXT?: Adequately powered randomised controlled trials comparing early to later oral anticoagulation with DOACs in ischaemic stroke associated with atrial fibrillation are justified to confirm the acceptable safety and efficacy of this strategy. Four such randomised controlled trials (collectively planned to include around 9000 participants) are underway, either using single cutoff timepoints for early versus late DOAC-administration initiation, or selecting DOAC-administration timing according to the severity and imaging features of the ischaemic stroke. The results of these trials should help to establish the optimal timing to initiate DOAC administration after recent ischaemic stroke and whether the timing should differ according to stroke severity. Results of these trials are expected from 2021.

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