What anticoagulant (blood thinner) is recommended for patients with posterior circulation stroke?

Anticoagulation in Posterior Circulation Stroke

For patients with posterior circulation stroke, antiplatelet therapy is the recommended first-line treatment, with aspirin (75-100 mg daily), clopidogrel (75 mg daily), or aspirin/extended-release dipyridamole (25 mg/200 mg twice daily) being the preferred options. 1

Initial Management

• For acute ischemic syndromes involving the vertebral artery territory with angiographic evidence of thrombus at the origin or extracranial portion, anticoagulation is generally recommended for at least 3 months 1
• In patients with symptomatic posterior circulation disease, antiplatelet therapy has demonstrated efficacy in reducing recurrent ischemic events 1, 2
• Ticlopidine has shown superiority to aspirin for secondary prevention of ischemic events in patients with symptomatic posterior circulation disease 1

Antiplatelet Options

• First-line antiplatelet options include:

  • Aspirin (75-100 mg once daily) 1
  • Clopidogrel (75 mg once daily) 1
  • Aspirin/extended-release dipyridamole (25 mg/200 mg twice daily) 1
  • Cilostazol (100 mg twice daily) 1

• Of these options, clopidogrel or aspirin/extended-release dipyridamole are preferred over aspirin alone 1

• In the ESPS-2 trial, the combination of low-dose aspirin and sustained-release dipyridamole twice daily reduced vertebrobasilar territory stroke or TIA to 5.7% compared with 10.8% in those given placebo 1

Special Considerations

• For patients with posterior circulation stroke and atrial fibrillation:

  • Oral anticoagulation is recommended over no antithrombotic therapy, aspirin alone, or combination therapy with aspirin and clopidogrel 1, 3
  • Non-vitamin K antagonist oral anticoagulants (NOACs) are preferred over vitamin K antagonists due to lower risk of major bleeding and death 3
  • Oral anticoagulation should generally be initiated within 1-2 weeks after stroke onset 1

• For patients with posterior circulation minor stroke or TIA:

  • Dual antiplatelet therapy with ticagrelor-aspirin has shown superiority over clopidogrel-aspirin in reducing the risk of stroke recurrence within 90 days 4
  • The benefit of dual antiplatelet therapy appears consistent regardless of whether the stroke is in the posterior or anterior circulation 4

Timing Considerations

• For patients with hemorrhagic transformation:

  • Lower-grade hemorrhagic transformation (HI1): Initiate antiplatelet therapy within 24-48 hours after confirming no progression of bleeding 5
  • Higher-grade hemorrhagic transformation (HI2, PH1, PH2): Delay antiplatelet therapy for 7-10 days 5

• For patients requiring anticoagulation (e.g., those with atrial fibrillation):

  • Earlier anticoagulation can be considered for patients at low risk of bleeding complications 1
  • Delaying anticoagulation should be considered for patients at high risk of hemorrhagic complications 1

Common Pitfalls to Avoid

• Avoid immediate reinstitution of antiplatelet therapy in patients with higher-grade hemorrhagic transformation 5
• Do not delay antiplatelet therapy unnecessarily for minor hemorrhagic transformations, as this may increase risk of recurrent ischemic events 5
• Avoid initiating dual antiplatelet therapy before confirming absence of hemorrhagic transformation on neuroimaging 5
• Don't overlook the need for catheter-based contrast angiography before revascularization, as MRA and CTA do not reliably delineate the origins of the vertebral arteries 1, 2

Monitoring and Follow-up

• For patients who have undergone vertebral artery revascularization, serial noninvasive imaging of the extracranial vertebral arteries is reasonable at intervals similar to those for carotid revascularization 1
• Regular monitoring for bleeding complications is essential, particularly when using dual antiplatelet therapy or anticoagulation 1, 5