Design of the Swiss Atrial Fibrillation Cohort Study (Swiss-AF): structural brain damage and cognitive decline among patients with atrial fibrillation.

David Conen,Matthias Schwenkglenks,Marcello Di Valentino,Angelo Auricchio,Laurent Roten,Georg Ehret,Christoph Stippich,Giorgio Moschovitis,Andreas U Monsch ,Richard Kobza,Jens Wuerfel,Dipen Shah,Christian Sticherling,Juerg Schlaepfer,Daniel Hayoz,Peter Ammann,Nicolas Rodondi,Ulrich Fischer ,Paul Erne,Jan Novak,Leo H Bonati ,Andreas Mueller,Juerg H Beer ,M Kuehne ,Stefan Osswald

doi:10.4414/smw.2017.14467

Abstract

Several studies found that patients with atrial fibrillation (AF) have an increased risk of cognitive decline and dementia over time. However, the magnitude of the problem, associated risk factors and underlying mechanisms remain unclear. This article describes the design and methodology of the Swiss Atrial Fibrillation (Swiss-AF) Cohort Study, a prospective multicentre national cohort study of 2400 patients across 13 sites in Switzerland. Eligible patients must have documented AF. Main exclusion criteria are the inability to provide informed consent and the presence of exclusively short episodes of reversible forms of AF. All patients undergo extensive phenotyping and genotyping, including repeated assessment of cognitive functions, quality of life, disability, electrocardiography and cerebral magnetic resonance imaging. We also collect information on health related costs, and we assemble a large biobank. Key clinical outcomes in Swiss-AF are death, stroke, systemic embolism, bleeding, hospitalisation for heart failure and myocardial infarction. Information on outcomes and updates on other characteristics are being collected during yearly follow-up visits. Up to 7 April 2017, we have enrolled 2133 patients into Swiss-AF. With the current recruitment rate of 15 to 20 patients per week, we expect that the target sample size of 2400 patients will be reached by summer 2017. Swiss-AF is a large national prospective cohort of patients with AF in Switzerland. This study will provide important new information on structural and functional brain damage in patients with AF and on other AF related complications, using a large variety of genetic, phenotypic and health economic parameters.

Highlights

Atrial fibrillation (AF) is the most common cardiac arrhythmia in the general population [1, 2]
The relative risk (95% confidence interval) of cognitive impairment in a meta-analysis of 21 individual studies was 1.34 (1.13–1.58) in individuals with atrial fibrillation (AF) without a prior stroke, and 2.70 (1.82–4.00) in those with a prior stroke [11]. These data suggest that a prior stroke substantially increases the risk of cognitive impairment in AF patients
Cerebral microbleeds are another structural correlate that potentially explain the link between AF and cognitive dysfunction [14], as some studies found a higher prevalence of microbleeds in patients with stroke or transient ischaemic attack (TIA) and a history of AF [15]

Summary

Introduction

Atrial fibrillation (AF) is the most common cardiac arrhythmia in the general population [1, 2]. 2) are another structural correlate that potentially explain the link between AF and cognitive dysfunction [14], as some studies found a higher prevalence of microbleeds in patients with stroke or transient ischaemic attack (TIA) and a history of AF [15]. Other factors such as progression of the arrhythmia, concomitant diseases or medical treatments may contribute to the cognitive decline in AF patients. We describe the detailed methodology of the Swiss Atrial Fibrillation (Swiss-AF) cohort study

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Discussion

Conclusion