What are the guidelines for Dual Antiplatelet Therapy (DAPT) in patients with ischemic stroke?

Guidelines for Dual Antiplatelet Therapy (DAPT) in Ischemic Stroke

Dual antiplatelet therapy should be initiated early (within 12-24 hours) and continued for 21-30 days in patients with minor ischemic stroke or high-risk TIA, followed by long-term single antiplatelet therapy to reduce recurrent stroke risk while minimizing bleeding complications. 1

Patient Selection for DAPT

Indications for Short-Term DAPT:

• Minor ischemic stroke (NIHSS ≤3) or high-risk TIA (ABCD2 score ≥4) 1
• Mild-moderate ischemic stroke (NIHSS ≤5) or high-risk TIA (ABCD2 score ≥4) 1
• Intracranial atherosclerotic stenosis (50-99%) 1

DAPT Regimens:

1. Aspirin + Clopidogrel:

   • Loading dose: Aspirin 160-325mg + Clopidogrel 300mg (CHANCE trial) or 600mg (POINT trial)
   • Maintenance: Aspirin 81mg daily + Clopidogrel 75mg daily
   • Duration: 21 days 1
   • Follow with: Single antiplatelet therapy (aspirin 81mg daily or clopidogrel 75mg daily)

2. Aspirin + Ticagrelor:

   • Loading dose: Aspirin 300-325mg + Ticagrelor 180mg
   • Maintenance: Aspirin 75-100mg daily + Ticagrelor 90mg twice daily
   • Duration: 30 days 1
   • Follow with: Single antiplatelet therapy

Duration of Therapy

Short-Term DAPT (Recommended):

• 21 days for aspirin + clopidogrel 1
• 30 days for aspirin + ticagrelor 1

Long-Term DAPT (Not Recommended):

• DAPT beyond 90 days is associated with significantly increased risk of ICH and major bleeding without additional benefit in stroke reduction 1
• Triple antiplatelet therapy is not recommended due to increased bleeding risk 1

Efficacy and Safety Considerations

Efficacy:

• DAPT reduces risk of recurrent stroke by 24% compared to aspirin alone 2
• Number needed to treat to prevent one primary outcome event: 92 1

Safety:

• DAPT increases risk of severe or moderate bleeding (RR 2.17,95% CI 1.16-4.08) 2
• Number needed to harm for severe bleeding: 263 1
• Bleeding risk is higher with:
  • DAPT duration >21 days 2
  • Older patients 1
  • More severe stroke 1

Special Populations

Intracranial Atherosclerotic Stenosis:

• DAPT is appropriate medical therapy for patients with moderate to high-grade intracranial atherosclerotic stenosis (50-99%) 1
• Angioplasty and stenting are not recommended 1

Embolic Stroke of Undetermined Source (ESUS):

• Antiplatelet therapy is recommended rather than oral anticoagulants 1

Extracranial Artery Dissection:

• Either antiplatelet therapy or oral anticoagulants for at least 3 months 1

Long-Term Single Antiplatelet Options

After completing short-term DAPT, transition to one of the following:

• Aspirin 81-325mg daily
• Clopidogrel 75mg daily
• Aspirin 25mg + extended-release dipyridamole 200mg twice daily 1, 3

Practical Implementation Tips

1. Timing is critical: Initiate DAPT as early as possible (ideally within 12-24 hours) after symptom onset 1, 3
2. Exclude hemorrhage: Always rule out intracranial hemorrhage on neuroimaging before starting DAPT 1
3. Monitor for bleeding: Watch for both minor (bruising) and major (intracranial) bleeding complications 4
4. Clear transition plan: Have a definitive plan to switch from DAPT to single antiplatelet therapy after the recommended duration 1
5. Patient education: Inform patients about the short-term nature of DAPT and the importance of transitioning to long-term single antiplatelet therapy

Common Pitfalls to Avoid

1. Continuing DAPT too long: Using DAPT beyond the recommended duration increases bleeding risk without additional benefit 1, 5
2. Delaying DAPT initiation: Maximum benefit occurs with early initiation (within 24 hours) 2, 6
3. Using DAPT in patients with high bleeding risk: Consider individual bleeding risk factors before initiating DAPT
4. Not excluding intracranial hemorrhage: Always obtain neuroimaging before starting DAPT 1
5. Failing to transition to single antiplatelet therapy: Have a clear plan to switch to long-term therapy after the DAPT period 1

By following these evidence-based guidelines, clinicians can optimize the benefit-risk ratio of antiplatelet therapy in patients with ischemic stroke or TIA, reducing recurrent stroke risk while minimizing bleeding complications.