Dual Antiplatelet Therapy for Secondary Stroke Prevention
For patients with minor ischemic stroke (NIHSS ≤3) or high-risk TIA (ABCD2 ≥4), dual antiplatelet therapy (DAPT) should be initiated within 12-24 hours of symptom onset and continued for 21 days, followed by long-term single antiplatelet therapy. 1
Initial DAPT Regimen
For Minor Ischemic Stroke or High-Risk TIA:
- Loading doses:
- Aspirin: 160-325 mg loading dose
- Clopidogrel: 300-600 mg loading dose (300 mg as per CHANCE trial or 600 mg as per POINT trial) 1
- Maintenance doses:
- Aspirin: 81 mg daily
- Clopidogrel: 75 mg daily
- Duration: 21 days 1
Alternative DAPT Regimen (for NIHSS ≤5):
- Loading doses:
- Aspirin: 300-325 mg loading dose
- Ticagrelor: 180 mg loading dose
- Maintenance doses:
- Aspirin: 75-100 mg daily
- Ticagrelor: 90 mg twice daily
- Duration: 30 days 1
Long-Term Antiplatelet Therapy
After completing the short-term DAPT course, transition to single antiplatelet therapy with one of the following:
- Aspirin 81 mg daily, OR
- Clopidogrel 75 mg daily 1
Special Considerations
Intracranial Atherosclerotic Disease
- For patients with stroke related to severe stenosis (70-99%) of a major intracranial artery, DAPT may be extended up to 90 days 1
Timing of Initiation
- Early initiation of DAPT (within 12-24 hours of symptom onset) provides greater benefit in preventing recurrent events 1
- Treatment should only be started after excluding intracranial hemorrhage on neuroimaging 1
Swallowing Difficulties
- For patients with impaired swallowing:
- Rectal aspirin 325 mg daily, OR
- Aspirin 81 mg daily via enteral tube, OR
- Clopidogrel 75 mg daily via enteral tube 1
Evidence-Based Rationale
Short-term DAPT (≤3 months) significantly reduces the risk of recurrent ischemic stroke by 26-41% and major vascular events by 24-30% compared to single antiplatelet therapy 2, 3, 4. Meta-analyses have demonstrated that DAPT initiated within 24 hours of symptom onset reduces the risk of recurrent stroke (RR: 0.74; 95% CI: 0.67-0.83) and major adverse cardiovascular events (RR: 0.76; 95% CI: 0.68-0.84) 3, 4.
However, prolonged DAPT (≥1 year) increases the risk of major bleeding and intracranial hemorrhage without providing additional benefits in stroke prevention 1, 2. The risk of moderate or severe bleeding is significantly higher with DAPT compared to aspirin alone (RR: 1.88; 95% CI: 1.10-3.23) 3.
Choice Between Clopidogrel and Ticagrelor
Both clopidogrel-aspirin and ticagrelor-aspirin combinations are superior to aspirin alone in preventing recurrent stroke and death, with no statistically significant difference between the two DAPT regimens (HR: 0.94; 95% CI: 0.78-1.13) 5. However, clopidogrel-aspirin has been associated with decreased risk of functional disability compared to ticagrelor-aspirin (HR: 0.85; 95% CI: 0.75-0.97) 5.
Important Caveats
- DAPT should not be used in patients requiring oral anticoagulation (e.g., atrial fibrillation) 1
- Always exclude intracranial hemorrhage before initiating antiplatelet therapy 1
- Monitor for bleeding complications throughout the DAPT course
- The benefit of DAPT is most pronounced in the first few weeks after stroke/TIA, while bleeding risk increases with longer duration 1, 2
By following this evidence-based approach to DAPT in stroke patients, clinicians can optimize secondary stroke prevention while minimizing bleeding complications.