What is the recommended treatment for a patient with a history of non-traumatic complete occlusion of the vertebral artery if they experience a dissection?

Treatment of Vertebral Artery Dissection in Patients with Pre-existing Complete Occlusion

For patients with vertebral artery dissection, initiate antithrombotic therapy immediately for at least 3-6 months using either antiplatelet agents or anticoagulation, as both approaches demonstrate equivalent efficacy in preventing recurrent ischemic events. 1

Initial Antithrombotic Management

The choice between anticoagulation and antiplatelet therapy is reasonable based on individual bleeding risk, as the CADISS trial demonstrated no statistically significant difference between these approaches 1:

• Anticoagulation option: Intravenous heparin followed by warfarin (target INR 2.0-3.0) results in stroke/death rates of 1% at 3 months and 1.6% at 1 year 1, 2
• Antiplatelet option: Aspirin (81-325 mg daily) or clopidogrel (75 mg daily) results in stroke/death rates of 2% at 3 months and 3.2% at 1 year 1, 2

The 2021 American Heart Association/American Stroke Association guidelines provide Class I evidence that antithrombotic therapy for at least 3 months is indicated to prevent recurrent stroke or TIA 1. The specific choice between anticoagulation versus antiplatelet therapy carries a Class 2a recommendation, with both being reasonable options 1.

Critical Contraindication

Never initiate anticoagulation if intracranial extension of the dissection with subarachnoid hemorrhage is present, as intracranial vertebrobasilar dissections carry substantially higher rupture risk 1, 2. This represents an absolute contraindication where anticoagulation may adversely influence outcomes 1.

Transition to Long-Term Therapy

After the initial 3-6 month treatment period, transition to long-term antiplatelet therapy with aspirin or clopidogrel is recommended 1. No uniform approach exists regarding the precise timing of this transition, but it typically occurs once acute symptoms resolve 1.

Endovascular Intervention Criteria

Reserve endovascular revascularization (stenting or coiling) exclusively for patients with persistent or recurrent ischemic symptoms despite optimal antithrombotic therapy 1, 2. This carries a Class 2b recommendation 1. The evidence shows:

• Periprocedural neurological complications occur in 5.5% of cases 2
• Restenosis develops in 26% at 12-month follow-up 2
• Surgical options include direct vertebral artery repair or resection with vein graft replacement 1

Prognosis and Natural History

With appropriate antithrombotic treatment, the prognosis is generally favorable 1:

• Anatomic healing occurs spontaneously in 72-100% of patients with medical management alone 1, 2
• Dissections that fail to heal anatomically are not associated with increased recurrent stroke risk, so further intervention for asymptomatic lesions is not warranted 1, 2
• The annual rate of recurrent stroke, TIA, or death is 8.3% with anticoagulants versus 12.4% with aspirin in observational data 1, 2

Common Pitfalls to Avoid

Do not pursue endovascular intervention for asymptomatic dissections that have not fully healed anatomically, as these do not carry increased recurrent stroke risk and intervention carries significant procedural risks 1, 2. The primary mechanism of stroke in extracranial dissection is artery-to-artery embolism from intraluminal thrombus, which justifies the antithrombotic approach rather than anatomic repair 1, 2.