What is the management of posterior circulation stroke?

Management of Posterior Circulation Stroke

Posterior circulation stroke requires prompt recognition and aggressive management with intravenous thrombolysis and/or endovascular thrombectomy, followed by appropriate secondary prevention measures tailored to the underlying etiology.

Clinical Presentation and Recognition

• Posterior circulation strokes account for approximately 20% of all ischemic strokes but can be challenging to diagnose due to non-specific symptoms 1
• Common symptoms include loss of consciousness, headache, nausea, vomiting, dizziness, double vision, hearing loss, slurred speech, vertigo, imbalance, and unilateral extremity weakness 1
• Physical examination may reveal ataxia, nystagmus, and visual field defects 1, 2
• The National Institutes of Health Stroke Scale (NIHSS) may underestimate severity in posterior circulation strokes as it focuses more on limb and speech impairments rather than cranial nerve lesions 1, 3

Acute Management

Initial Assessment and Imaging

• Non-contrast CT is used to exclude hemorrhage, but has limitations in the posterior fossa due to beam hardening artifacts 1
• MRI is preferred for diagnosing posterior fossa lesions, with diffusion-weighted imaging being particularly sensitive 1
• CT angiography or MR angiography should be performed to identify large vessel occlusions 1
• Posterior circulation Alberta Stroke Program Early CT Score (pc-ASPECTS) ≥8 is associated with better outcomes 1

Reperfusion Therapy

1. Intravenous Thrombolysis

   • Intravenous alteplase (0.9 mg/kg, maximum 90 mg, with 10% given as bolus and remainder over 60 minutes) is recommended within 4.5 hours of symptom onset 1
   • Intravenous thrombolysis appears appropriate as first-line therapy for posterior circulation stroke 1
   • In patients with basilar artery occlusion, expert consensus suggests using IVT up to 24 hours unless contraindicated 1

2. Endovascular Treatment (EVT)

   • For basilar artery occlusion, EVT plus best medical treatment is suggested over best medical treatment alone, particularly in patients with NIHSS ≥10 1
   • Mechanical thrombectomy using stent retrievers or large bore distal aspiration catheters has shown high recanalization rates (up to 92%) 1
   • Successful recanalization is a strong predictor of survival in basilar artery occlusion 1
   • Failure of recanalization is associated with high mortality 1

3. Combined Approach

   • The combined intravenous and endovascular approach to recanalization appears safe and is currently under investigation 1
   • Evidence suggests IVT plus EVT over direct EVT for basilar artery occlusion 1

Management of Complications

• Blood Pressure Management: Maintain systolic blood pressure between 121-200 mmHg and diastolic pressure between 81-110 mmHg in the first 24 hours unless it exceeds 220/120 mmHg 1
• Glucose Management: Maintain blood glucose between 140-180 mg/dL 1
• Decompressive Surgery: Consider decompressive hemicraniectomy for malignant middle cerebral artery stroke, particularly in patients under 60 years 1
• Dysphagia Management: In dysphagic patients, ASA (80 mg daily) and clopidogrel (75 mg daily) may be given by enteral tube or ASA by rectal suppository (325 mg daily) 1

Secondary Prevention

Antithrombotic Therapy

• For high-risk TIA or minor stroke, dual antiplatelet therapy with aspirin and clopidogrel is recommended for 21-90 days, followed by single antiplatelet therapy 1
• For patients with very high risk of recurrent stroke (symptom onset within 48 hours), aggressive antithrombotic therapy should be initiated 1
• GI protection may be considered in patients on dual antiplatelet therapy who are at higher risk of GI bleeding 1

Management of Specific Etiologies

1. Vertebral Artery Disease

   • Medical management should follow guidelines for carotid artery disease 1
   • For patients with acute ischemic syndromes involving vertebral artery territory with angiographic evidence of thrombus, anticoagulation is generally recommended for at least 3 months 1

2. Basilar Artery Stenosis

   • Randomized controlled trial data suggest basilar artery stenosis is better treated with medical therapy than stenting due to high peri-procedural risk 4
   • Intracranial stenosis is currently best treated with medical therapy alone 4

3. Vertebral Artery Stenosis

   • For extracranial vertebral stenosis, stenting may be an option for symptomatic stenosis, particularly for recurrent symptoms 4
   • The situation for extracranial stenosis is less clear and larger randomized controlled trials are needed 4

Special Considerations

• Patients with posterior circulation stroke may have a higher rate of small vessel disease and lacunar stroke compared to anterior circulation stroke 5
• The POST-NIHSS (Posterior NIHSS) has been developed to improve prognostic accuracy for posterior circulation stroke patients with mild-moderate symptoms by adding points for abnormal cough, dysphagia, and gait/truncal ataxia 3
• Predictors of poor outcome include older age, higher NIHSS score, lack of recanalization, atrial fibrillation, intracranial hemorrhage, and pc-ASPECTS ≤8 1

Follow-up and Monitoring

• Aggressive treatment of cerebrovascular risk factors with both drugs and lifestyle interventions is essential 4
• Regular follow-up imaging may be necessary to monitor for restenosis, particularly in patients who have undergone interventional procedures 1
• Restenosis generally does not require revascularization unless it leads to recurrent ischemic symptoms or progresses to preocclusive severity 1