What is the recommended antiplatelet therapy for patients with posterior circulation stroke?

Antiplatelet Therapy for Posterior Circulation Stroke

For patients with posterior circulation stroke, antiplatelet therapy is recommended as the first-line treatment for secondary stroke prevention, with options including aspirin (50-325 mg daily), clopidogrel (75 mg daily), or the combination of aspirin (25 mg twice daily) plus extended-release dipyridamole (200 mg twice daily). 1

Initial Antiplatelet Selection

• Single antiplatelet therapy with aspirin (50-325 mg daily), clopidogrel (75 mg daily), or the combination of aspirin plus extended-release dipyridamole is recommended for long-term secondary prevention in posterior circulation stroke 1
• For patients with acute posterior circulation stroke who were not previously on an antiplatelet agent, a loading dose of aspirin 160-325 mg should be administered after intracranial hemorrhage is ruled out 1
• For patients with swallowing difficulties, rectal aspirin (325 mg daily) or enteral administration of aspirin (81 mg daily) or clopidogrel (75 mg daily) are reasonable alternatives 1

Short-term Dual Antiplatelet Therapy (DAPT)

• For patients with minor ischemic stroke (NIHSS ≤3) or high-risk TIA (ABCD2 ≥4) in the posterior circulation, DAPT with aspirin and clopidogrel should be initiated within 12-24 hours of symptom onset 1

  • Loading doses: aspirin (160-325 mg) and clopidogrel (300-600 mg)
  • Maintenance: aspirin 81 mg daily and clopidogrel 75 mg daily
  • Duration: 21 days, followed by single antiplatelet therapy 1, 2

• Alternative DAPT option for mild-moderate stroke (NIHSS ≤5): aspirin plus ticagrelor for 30 days 1

  • Loading doses: aspirin (300-325 mg) and ticagrelor (180 mg)
  • Maintenance: aspirin 75-100 mg daily and ticagrelor 90 mg twice daily
  • Duration: 30 days, followed by single antiplatelet therapy 1

Special Considerations for Posterior Circulation

Vertebrobasilar Dolichoectasia

• For patients with vertebrobasilar dolichoectasia, antiplatelet therapy is recommended over anticoagulation 1
• There is insufficient evidence to recommend anticoagulation over antiplatelet therapy for this condition 1

Extracranial Vertebral Artery Disease

• Optimal medical therapy including antiplatelet therapy, statin therapy, and risk factor modification is recommended for all patients with vertebral artery stenosis 1
• Endovascular or surgical treatment may be considered only when patients remain symptomatic despite optimal medical treatment 1

Intracranial Atherosclerosis

• For patients with posterior circulation stroke due to 50-99% stenosis of a major intracranial artery, aspirin is recommended in preference to warfarin 1
• For patients with moderate to high-grade intracranial atherosclerotic stenosis (50-99%), dual antiplatelet therapy with aspirin and clopidogrel for 90 days may be beneficial 1
• Long-term blood pressure control (<140/90 mmHg) and total cholesterol level <200 mg/dL are recommended 1

Comparative Effectiveness

• Compared to aspirin alone, clopidogrel has shown superior efficacy in reducing the risk of all strokes, cardiovascular events, and intracranial hemorrhage 3
• Short-term DAPT reduces the risk of recurrent stroke compared to aspirin alone but increases the risk of major bleeding 2
• In elderly patients and those with stenosis in the posterior circulation or basilar artery, LMWH or DAPT may be more effective than aspirin alone for reducing early neurological deterioration and improving 6-month outcomes 4

Duration of Therapy

• Antiplatelet therapy should be continued indefinitely for long-term secondary stroke prevention unless contraindicated 1
• Dual antiplatelet therapy should not be used long-term (>90 days) due to increased bleeding risk 1, 5

Monitoring and Safety

• Regular monitoring for bleeding complications is essential, especially during DAPT 2
• The addition of aspirin to clopidogrel for long-term use increases bleeding risk without providing additional benefit 1
• For patients who experience a stroke while taking aspirin, switching to an alternative antiplatelet agent (such as clopidogrel) may be considered, although evidence for this approach is limited 1

Pitfalls to Avoid

• Avoid long-term DAPT (>90 days) due to increased bleeding risk without additional benefit 1, 5
• Do not use oral anticoagulation for non-cardioembolic posterior circulation stroke unless there is a specific indication (e.g., atrial fibrillation) 1
• Do not use angioplasty and stenting as first-line therapy for patients with posterior circulation stroke due to intracranial stenosis 1