Do we use anti-platelet (anti-thrombotic) therapy for stroke prevention in patients with atrial fibrillation?

Anticoagulation, Not Antiplatelet Therapy, Is Required for Stroke Prevention in Atrial Fibrillation

Antiplatelet therapy is not recommended for stroke prevention in patients with atrial fibrillation, as oral anticoagulation is the only appropriate therapy for reducing stroke risk in these patients. 1

Risk Assessment and Appropriate Therapy Selection

The decision to initiate stroke prevention therapy in atrial fibrillation should be based on stroke risk assessment:

1. Risk Stratification:

   • Use CHA₂DS₂-VA(Sc) score to determine stroke risk 1
   • Score ≥2 indicates elevated thromboembolic risk requiring oral anticoagulation 1
   • Even patients with a single non-sex CHA₂DS₂-VASc risk factor should be offered stroke prevention 1

2. Recommended Therapy by Risk Level:

   • High risk (CHA₂DS₂-VASc ≥2): Oral anticoagulation is mandatory 1
   • Intermediate risk (CHA₂DS₂-VASc = 1): Oral anticoagulation is recommended over no therapy or antiplatelet therapy 1
   • Low risk (CHA₂DS₂-VASc = 0): No antithrombotic therapy is suggested; if therapy desired, aspirin is suggested over oral anticoagulation 1

Antiplatelet Therapy: Not Appropriate for AF-Related Stroke Prevention

The evidence clearly demonstrates that antiplatelet therapy is inadequate for stroke prevention in AF:

• Antiplatelet therapy is explicitly not recommended as an alternative to anticoagulation for stroke prevention in AF patients 1
• Strong recommendation (Class III, Level A) against using antiplatelet therapy alone for stroke prevention in AF 1
• Adding antiplatelet treatment to oral anticoagulation is not recommended for preventing ischemic stroke in AF patients 1
• Dual antiplatelet therapy (aspirin plus clopidogrel) is also not recommended over oral anticoagulation 1

Recommended Anticoagulation Options

For patients requiring anticoagulation:

1. First-line therapy: Direct oral anticoagulants (DOACs) are recommended over vitamin K antagonists (VKAs) 1

   • Exception: Patients with mechanical heart valves or moderate-to-severe mitral stenosis should receive VKAs 1

2. If VKAs are used:

   • Target INR should be 2.0-3.0 1
   • Time in therapeutic range (TTR) should be ≥70% 1
   • Consider switching to a DOAC if TTR <70% 1

3. DOAC dosing:

   • Use full-dose therapy unless specific criteria for dose reduction are met 1
   • Inappropriate dose reduction increases thromboembolic risk 1

Special Considerations

• Bleeding risk assessment: Evaluate and manage modifiable bleeding risk factors in all patients eligible for oral anticoagulation 1
• Temporal pattern: The pattern of AF (paroxysmal, persistent, or permanent) should not determine the need for oral anticoagulation 1
• Patients with prior stroke: These patients automatically have a CHA₂DS₂-VASc score ≥2 and require anticoagulation 2

Common Pitfalls to Avoid

1. Inappropriate use of antiplatelet therapy: Using aspirin alone or dual antiplatelet therapy instead of oral anticoagulation significantly increases stroke risk 1, 3

2. Discontinuing anticoagulation after rhythm control: Anticoagulation decisions should be based on CHA₂DS₂-VASc score regardless of current rhythm status 2

3. Underdosing DOACs: Reducing DOAC doses without meeting specific criteria leads to inadequate stroke protection 1

4. Using bleeding risk scores to avoid anticoagulation: Bleeding risk assessment should focus on identifying and managing modifiable risk factors, not avoiding necessary anticoagulation 1

In summary, antiplatelet therapy has no role in stroke prevention for patients with atrial fibrillation. Oral anticoagulation remains the cornerstone of therapy, with DOACs preferred over VKAs in most patients.