Atrial Fibrillation Patients Do Not Benefit From Acetylsalicylic Acid

Sara Själander; Anders Själander; Peter J. Svensson; Leif Friberg


Europace. 2014;16(5):631-638. 

In This Article

Abstract and Introduction


Aims Oral anticoagulation is the recommended treatment for stroke prevention in patients with atrial fibrillation. Notwithstanding, many patients are treated with acetylsalicylic acid (ASA) as monotherapy. Our objective was to investigate if atrial fibrillation patients benefit from ASA as monotherapy for stroke prevention.

Methods and Results Retrospective study of patients with a clinical diagnosis of atrial fibrillation between 1 July 2005 and 1 January 2009 in the National Swedish Patient register, matched with data from the National Prescribed Drugs register. Endpoints were ischaemic stroke, thrombo-embolic event, intracranial haemorrhage, and major bleeding. The study population consisted of 115 185 patients with atrial fibrillation, of whom 58 671 were treated with ASA as monotherapy and 56 514 were without any antithrombotic treatment at baseline. Mean follow-up was 1.5 years. Treatment with ASA was associated with higher risk of ischaemic stroke and thrombo-embolic events compared with no antithrombotic treatment.

Conclusion Acetylsalicylic acid as monotherapy in stroke prevention of atrial fibrillation has no discernable protective effect against stroke, and may even increase the risk of ischaemic stroke in elderly patients. Thus, our data support the new European guidelines recommendation that ASA as monotherapy should not be used as stroke prevention in atrial fibrillation.


Atrial fibrillation (AF) is the most common of all cardiac arrhythmias, and a major cause of stroke.[1,2] Oral anticoagulation is the recommended prophylactic treatment for most patients on the grounds that it confers a 64% reduction in stroke risk,[3] while acetylsalicylic acid (ASA) has been an option for low-risk patients or for patients who cannot take oral anticoagulants. However, the net benefit of ASA has been questioned in recent years, since the absolute benefit of oral anticoagulation has been shown to increase, and the benefit of antiplatelet agents appears to decrease with increasing age.[4] At the same time, the rate of serious bleeding is equal between patients receiving oral anticoagulation and antiplatelet agents in the elderly (>80 years of age).[4] In clinical practice, however, ASA is still widely used and often so by the patients who are at the highest risk of stroke; elderly patients and patients with many stroke risk factors.

The aims of this study were to assess the prevalence and net clinical benefit of ASA as monotherapy for stroke prevention of AF.