Does aspirin (acetylsalicylic acid) help prevent cerebral vascular accident (CVA) in patients with paroxysmal atrial fibrillation?

From the Guidelines

Aspirin is not recommended as the primary preventive measure for cerebral vascular accidents (CVAs) in patients with paroxysmal atrial fibrillation, due to its limited efficacy compared to oral anticoagulants. For stroke prevention in atrial fibrillation, including paroxysmal forms, oral anticoagulants such as warfarin or direct oral anticoagulants (DOACs) like apixaban, rivaroxaban, dabigatran, or edoxaban are the preferred medications 1. The choice of anticoagulant should be based on the patient's stroke risk, typically assessed using the CHA₂DS₂-VASc score, which considers factors like age, sex, and comorbidities.

Key Points to Consider

• Aspirin offers only modest protection against stroke for patients with atrial fibrillation, with a stroke reduction of 19% (95% CI 2% to 34%) as shown in a meta-analysis of five randomized trials 1.
• The effect of aspirin on stroke in these trials was less consistent than that of oral anticoagulation 1.
• Aspirin may be more efficacious for atrial fibrillation patients with hypertension or diabetes, and for reduction of noncardioembolic vs cardioembolic ischemic strokes in atrial fibrillation patients 1.
• Oral anticoagulation is more efficacious than aspirin for prevention of stroke in patients with atrial fibrillation, with a 33% risk reduction (95% CI 13% to 49%) in a meta-analysis of five randomized trials 1.
• The combination of low-dose oral anticoagulation with aspirin adds little protection against stroke compared to aspirin alone in patients with atrial fibrillation 1.

Clinical Decision Making

When deciding on the best course of action for preventing CVAs in patients with paroxysmal atrial fibrillation, it is essential to consider the patient's individual risk factors and stroke risk score. The most recent and highest quality evidence suggests that oral anticoagulants are the preferred choice for stroke prevention in atrial fibrillation 1. Aspirin may be considered for patients at low risk of stroke or for those who cannot tolerate oral anticoagulants, but its use should be carefully weighed against the potential benefits and risks. Ultimately, the goal is to minimize the risk of morbidity, mortality, and reduce the impact on quality of life for patients with paroxysmal atrial fibrillation.

From the Research

Aspirin and CVA Prevention in Paroxysmal Atrial Fibrillation

• Aspirin has a limited role in stroke prevention for patients with atrial fibrillation, being an inferior strategy to anticoagulants like warfarin, especially in the elderly 2.
• The use of aspirin in combination with clopidogrel shows only modest benefit in stroke prevention compared to aspirin monotherapy in patients with atrial fibrillation who refuse oral anticoagulant drugs or have difficulties with anticoagulation monitoring 2.
• A mixed treatment comparison meta-analysis found that all treatments except aspirin reduced the risk of any stroke compared to placebo, with warfarin, apixaban, dabigatran, rivaroxaban, and aspirin with clopidogrel being more protective than aspirin alone 3.
• The role of antiplatelet therapy, specifically aspirin, in preventing strokes associated with atrial fibrillation remains controversial, with US guidelines conflicting with European guidelines that do not recommend antiplatelet monotherapy for stroke prevention irrespective of stroke risk 4.
• Dual antiplatelet therapy is not optimal for stroke prevention in patients with atrial fibrillation, as it increases the risk of major bleeding while providing limited benefit over aspirin monotherapy 5.

Comparison of Aspirin to Other Anticoagulants

• Warfarin and new anticoagulants, such as apixaban, dabigatran, edoxaban, and rivaroxaban, are more effective than aspirin in preventing stroke in patients with atrial fibrillation 3.
• Aspirin is associated with a similar risk of hemorrhagic events compared to anticoagulants, but its benefit in preventing strokes is limited 4.
• The AFASAK 2 study investigated the effect of four antithrombotic regimens, including fixed-dose warfarin, combination warfarin and aspirin, aspirin alone, and conventional warfarin therapy, in patients with atrial fibrillation 6.