In an adult with spontaneous vertebral artery dissection causing occlusion and an acute posterior circulation ischemic stroke, what is the recommended initial antiplatelet or anticoagulant therapy?

Antithrombotic Therapy for Spontaneous Vertebral Artery Dissection with Acute Posterior Circulation Stroke

Either antiplatelet therapy or anticoagulation may be initiated for at least 3 months in patients with vertebral artery dissection causing acute ischemic stroke, as both approaches are considered equally acceptable by current guidelines. 1

Acute Phase Management (First 48 Hours)

Thrombolysis Consideration (If Within 4.5 Hours)

Vertebral artery dissection is NOT a contraindication to intravenous alteplase when the patient presents within the therapeutic window and meets standard eligibility criteria. 1

• Administer IV alteplase 0.9 mg/kg (maximum 90 mg) with 10% as bolus over 1 minute, followed by 90% over 60 minutes, if the patient presents within 3 hours of symptom onset and meets NINDS criteria 1
• For patients presenting between 3-4.5 hours, alteplase may be given if ECASS III criteria are satisfied, with additional exclusions: age >80 years, oral anticoagulant use, NIHSS >25, or combined history of diabetes and prior stroke 1
• Mandatory pre-treatment requirements include non-contrast CT to exclude hemorrhage, blood pressure <185/110 mmHg, and bedside glucose >50 mg/dL 1

If Thrombolysis Is Not Given or Beyond 4.5 Hours

Initiate aspirin 160-325 mg within 48 hours after excluding intracranial hemorrhage on neuroimaging. 1

• Aspirin is strongly recommended over therapeutic anticoagulation in the acute phase (Grade 1A) 1
• Do not delay aspirin therapy beyond 48 hours in patients outside the thrombolytic window 2

Longer-Term Antithrombotic Strategy (After Acute Phase)

Guideline-Based Equipoise

The 2023 World Stroke Organization guidelines explicitly state that either antiplatelet therapy OR oral anticoagulation are recommended for at least 3 months in patients with extracranial vertebral artery dissection causing ischemic stroke or TIA. 1

Practical Decision Algorithm

When choosing between antiplatelet therapy and anticoagulation after the acute phase:

Favor antiplatelet therapy (aspirin 75-100 mg daily or clopidogrel 75 mg daily) if: 1

• The patient has completed thrombolysis (wait 24 hours after alteplase before starting) 3
• There is concern about bleeding risk
• The dissection shows signs of healing on follow-up imaging
• The patient has contraindications to anticoagulation

Favor anticoagulation (therapeutic-dose) if: 1

• There is documented thrombus formation at the dissection site
• The patient has recurrent ischemic events despite antiplatelet therapy
• There is evidence of ongoing arterial occlusion with hemodynamic compromise
• No contraindications to anticoagulation exist

Duration of Therapy

• Continue the chosen antithrombotic regimen for a minimum of 3 months 1
• Obtain follow-up vascular imaging (CTA or MRA) at 3 months to assess vessel healing 4
• If the vessel has healed completely, transition to long-term single antiplatelet therapy for secondary stroke prevention 1, 4
• If dissection persists or there is residual stenosis, consider extending anticoagulation or continuing dual management under specialist guidance 1

Critical Contraindications and Safety Considerations

Absolute Contraindications to Thrombolysis in This Setting

• Intracranial hemorrhage on initial CT 1
• Platelet count <100,000/mm³ 1
• INR >1.7 1
• Blood pressure that cannot be lowered to <185/110 mmHg 1
• Symptom onset >4.5 hours (Grade 1B recommendation against) 1, 2

Hemorrhagic Transformation Risk

• Symptomatic intracranial hemorrhage occurs in 2.4-6.4% of patients receiving alteplase 3
• The hemorrhage risk with thrombolysis in vertebral artery dissection is comparable to other stroke etiologies and does not appear elevated 4, 5

Common Pitfalls to Avoid

Do not withhold thrombolysis solely because of vertebral artery dissection—dissection is not listed as a contraindication in major guidelines, and case reports demonstrate safety and efficacy 1, 4, 5

Do not assume anticoagulation is superior to antiplatelet therapy—the 2023 guidelines place both options at equal recommendation strength, reflecting the lack of definitive comparative data 1

Do not delay aspirin beyond 48 hours in patients who do not receive thrombolysis—early aspirin (160-325 mg) is a Grade 1A recommendation and reduces early recurrent stroke risk 1

Do not continue dual antiplatelet therapy beyond 21-30 days unless the patient had a minor stroke (NIHSS ≤3-5) at presentation—the indication for DAPT is specific to minor stroke/high-risk TIA, not vertebral dissection per se 1

Do not forget to obtain follow-up vascular imaging at 3 months—spontaneous healing occurs in many cases, and documentation of vessel repair allows de-escalation of therapy 4