Should a patient with a history of stroke on aspirin (acetylsalicylic acid) who experiences recurrent transient ischemic attacks (TIAs) be switched to or have Plavix (clopidogrel) added to their regimen?

Management of Recurrent TIAs in a Patient on Aspirin with History of Stroke

For patients with recurrent transient ischemic attacks (TIAs) while on aspirin therapy who have a history of stroke, dual antiplatelet therapy with aspirin plus clopidogrel should be initiated for 21-90 days, followed by single antiplatelet therapy. 1

Initial Management

• For patients with recent minor (National Institutes of Health Stroke Scale ≤3) noncardioembolic ischemic stroke or high-risk TIA (ABCD2 score ≥4), dual antiplatelet therapy with aspirin plus clopidogrel should be initiated early (ideally within 12-24 hours of symptom onset) 1
• The recommended duration of dual antiplatelet therapy is 21-90 days, after which the patient should return to single antiplatelet therapy 1
• The combination therapy should be started promptly as most recurrent events occur within the first week after the initial event 2

Evidence Supporting Dual Antiplatelet Therapy

• Dual antiplatelet therapy with clopidogrel plus aspirin is associated with a lower risk of recurrent ischemic events compared to aspirin monotherapy (hazard ratio 0.75; 95% CI 0.59-0.95) 2
• Meta-analyses have shown that clopidogrel plus aspirin significantly reduces the risk of recurrent ischemic stroke (RR 0.72,95% CI 0.65-0.81) compared to aspirin monotherapy 3
• Short-duration DAPT (≤1 month) started during the early acute ischemic phase shows greater reduction of recurrent strokes compared with monotherapy 4

Bleeding Risk Considerations

• Dual antiplatelet therapy is associated with an increased risk of major hemorrhage (hazard ratio 2.32; 95% CI 1.10-4.87) compared to aspirin monotherapy 2
• The number needed to harm for intracranial bleeding is 258 and for major bleeding is 113 with dual antiplatelet therapy 4
• Short-duration DAPT (≤1 month) has been shown to have less bleeding risk than longer DAPT while maintaining efficacy 4

Important Contraindications

• Dual antiplatelet therapy should be avoided in patients with:
  • Active bleeding 5
  • Severe uncontrolled hypertension 6
  • Known allergies to either aspirin or clopidogrel 6
  • Hemophilia or other bleeding disorders 6

Long-term Management

• After the initial 21-90 day period of dual antiplatelet therapy, patients should return to single antiplatelet therapy 1
• For long-term secondary prevention, options include:
  • Aspirin (50-325 mg/day)
  • Clopidogrel (75 mg/day)
  • Combination of aspirin and extended-release dipyridamole 1

Special Considerations

• For patients with cardioembolic stroke (e.g., atrial fibrillation), oral anticoagulation is preferred over antiplatelet therapy 6
• For patients with ischemic stroke related to 50%-99% intracranial stenosis, aspirin 325 mg/day is recommended 1
• There is no evidence that increasing the dose of aspirin provides additional benefit for patients who have an ischemic event while taking aspirin 1

Monitoring and Follow-up

• Monitor for bleeding complications, especially during the dual antiplatelet therapy period 2
• Evaluate for other stroke risk factors and ensure optimal management of hypertension, diabetes, hyperlipidemia, and smoking cessation 1
• Consider CYP2C19 metabolizer status, as poor metabolizers may have reduced effectiveness with clopidogrel 5

The evidence strongly supports a time-limited course of dual antiplatelet therapy followed by single antiplatelet therapy in patients with recurrent TIAs while on aspirin. This approach balances the reduced risk of recurrent ischemic events against the increased risk of bleeding complications.