What is the recommended acute and secondary management for a posterior circulation (vertebrobasilar) ischemic stroke?

Management of Posterior Circulation (Vertebrobasilar) Ischemic Stroke

Acute Reperfusion Therapy

For patients with acute basilar artery occlusion presenting within 12 hours, endovascular thrombectomy combined with intravenous thrombolysis (if not contraindicated) is the standard of care and dramatically improves outcomes. 1

Patient Selection Criteria for Thrombectomy

• NIHSS score ≥6 1
• Posterior circulation ASPECTS (pc-ASPECTS) ≥6 1
• Age 18-89 years 1
• Basilar or vertebral artery occlusion confirmed on CTA 1

Time Windows for Intervention

• 0-12 hours from last known well: Thrombectomy is indicated (Class I, Level B-R) 1
• 12-24 hours from last known well: Thrombectomy is reasonable (Class IIa, Level B-R) 1
• Beyond 24 hours: Thrombectomy may be considered case-by-case (Class IIb, Level C-EO) 1

Intravenous Thrombolysis Protocol

Administer IV alteplase 0.9 mg/kg (maximum 90 mg) within 4.5 hours of symptom onset: 10% as bolus over 1 minute, remaining 90% infused over 60 minutes. 2, 1

• Do not delay IV thrombolysis for vascular imaging if the patient is within the treatment window—begin tPA before transport for additional imaging or endovascular therapy 2
• Combined IVT plus EVT is preferred over direct EVT alone when IVT is not contraindicated 1

Blood Pressure Management Before Thrombolysis

If systolic BP >185 mmHg or diastolic >110 mmHg, treat aggressively: 2

• Labetalol 10-20 mg IV over 1-2 minutes (may repeat once), OR
• Nitropaste 1-2 inches, OR
• Nicardipine drip starting at 5 mg/h, titrate up by 2.5 mg/h every 5-15 minutes (maximum 15 mg/h)
• Do not administer tPA if BP cannot be reduced and maintained at systolic ≤185 mmHg and diastolic ≤110 mmHg 2

Thrombectomy Technique

Direct Aspiration First Pass Technique (ADAPT) is recommended as first-line treatment, with stent retriever thrombectomy as rescue therapy if needed. 1

• ADAPT achieves higher rates of complete reperfusion (OR 2.59,95% CI 1.14-5.86) with shorter procedure duration (median 45 vs 56 minutes) and lower periprocedural complications (4.3% vs 25.9%) compared to stent retrievers 1
• Both techniques are reasonable options 1

Critical Diagnostic Pitfalls

Posterior circulation strokes are frequently missed because they present with non-specific symptoms (dizziness, nausea, headache, vertigo) and can have NIHSS scores of 0 despite devastating basilar artery occlusion. 2

Essential Imaging Protocol

• Complete non-contrast CT within 25 minutes of arrival 2
• Look for hyperdense basilar artery sign: sensitivity 71%, specificity 98% for basilar occlusion; density cut-off 40-42 Hounsfield units predicts poor outcome (mRS >2, OR 5.6) 2
• Perform CTA immediately ("aortic arch-to-vertex") to assess both extracranial and intracranial circulation 2
• MRA and CTA do not reliably delineate vertebral artery origins—catheter-based contrast angiography is typically required before revascularization 1, 3

Physical Examination Findings to Identify

• Ataxia (especially truncal ataxia) 2
• Nystagmus 2
• Visual field defects 2
• Cranial nerve palsies 2
• Loss of consciousness, double vision, hearing loss 2

Secondary Prevention

Antiplatelet Therapy

For patients with vertebral artery territory stroke with angiographic evidence of thrombus at the origin or extracranial portion, anticoagulation is recommended for at least 3 months. 3, 1

For other posterior circulation strokes, antiplatelet therapy is the cornerstone: 3

• Clopidogrel 75 mg daily (preferred over aspirin alone) 3
• Aspirin 75-100 mg plus extended-release dipyridamole 200 mg twice daily (preferred over aspirin alone; reduced vertebrobasilar events to 5.7% vs 10.8% with placebo in ESPS-2) 3, 1
• Ticlopidine 250 mg twice daily (superior to aspirin for symptomatic posterior circulation disease but less commonly used due to side effects) 3, 1

Timing of Antiplatelet Therapy After Hemorrhagic Transformation

• Lower-grade hemorrhagic transformation (HI1): Initiate antiplatelet therapy within 24-48 hours after confirming no progression of bleeding 3
• Higher-grade hemorrhagic transformation (HI2, PH1, PH2): Delay antiplatelet therapy for 7-10 days 3

Atrial Fibrillation Management

For patients with posterior circulation stroke and atrial fibrillation, oral anticoagulation is recommended over antiplatelet therapy alone. 3

• Initiate oral anticoagulation within 1-2 weeks after stroke onset 3

Vertebrobasilar Stenosis Management

Medical therapy is superior to stenting for symptomatic basilar artery stenosis due to high periprocedural risk. 4

• Aggressive treatment of cerebrovascular risk factors with medications and lifestyle interventions 4
• Intracranial vertebral stenosis: Medical therapy alone is currently best 4
• Extracranial vertebral stenosis: Stenting may be considered for recurrent symptoms despite medical therapy, but larger RCTs are needed 4

Management of Cerebellar Stroke Complications

Approximately 25% of patients develop mass effect causing rapid clinical deterioration, and 85% of patients progressing to coma die without intervention. 1

Monitoring Requirements

• Serial imaging in first 2 days to identify high-risk patients 1
• Mass effect can peak on day 3 but may occur throughout the first week 1
• Up to 20% develop hydrocephalus from ventricular or aqueductal obstruction 1

Surgical Intervention

Suboccipital craniectomy, durotomy, and duraplasty should be considered early for patients with mass effect and hydrocephalus. 1

• External ventricular drain alone carries risk of upward herniation and continued brainstem compression 1
• Half of patients progressing to coma treated with suboccipital decompression have good outcomes 1
• Conservative measures (head elevation, osmotic diuretics, hyperventilation) provide only transient benefit 1

Prognostic Factors

Mortality in basilar artery occlusion ranges from 45% to 86% without recanalization. 2

Predictors of poor outcome include: 2

• Older age
• Higher NIHSS score (though NIHSS significantly underestimates posterior circulation stroke severity)
• Lack of recanalization
• Atrial fibrillation
• Intracranial hemorrhage
• pc-ASPECTS ≤8

Critical caveat: NIHSS underestimates posterior circulation stroke severity because it focuses on limb/speech impairments rather than cranial nerve lesions and brainstem function. 2