What is the recommended acute and secondary treatment approach for a patient with posterior circulation (vertebro‑basilar) ischemic stroke?

Acute and Secondary Management of Posterior Circulation Stroke

Acute Reperfusion Therapy

For patients with basilar artery occlusion presenting within 12 hours, endovascular thrombectomy combined with intravenous alteplase (when not contraindicated) is the standard of care and markedly improves functional outcomes, reducing mortality from 55% to 37% and increasing good outcomes (mRS 0-3) from 23% to 46%. 1, 2

Intravenous Thrombolysis

• Administer alteplase 0.9 mg/kg (maximum 90 mg) within 4.5 hours of symptom onset: 10% as immediate bolus over 1 minute, remainder infused over 60 minutes 2, 3
• Do not withhold thrombolysis for mild or rapidly improving symptoms, as substantial proportions of these patients deteriorate 2
• When both IV thrombolysis and thrombectomy are permissible, the combination is preferred over direct thrombectomy alone 1, 2
• Posterior circulation strokes have similar thrombolysis benefits but lower hemorrhage risks compared to anterior circulation 4

Patient Selection Criteria for Thrombectomy

• NIHSS score ≥6 (though NIHSS significantly underestimates posterior circulation severity) 1, 2
• Posterior circulation ASPECTS (pc-ASPECTS) ≥6 on non-contrast CT 1, 2
• Age 18-89 years 1, 2
• Confirmed basilar or dominant vertebral artery occlusion on CTA 1, 2

Time Windows for Thrombectomy

Time from Last Known Well	Recommendation	Evidence Level
0-12 hours	Thrombectomy indicated	Class I, Level B-R
12-24 hours	Thrombectomy reasonable	Class IIa, Level B-R
>24 hours	Consider case-by-case	Class IIb, Level C-EO

1, 2

Thrombectomy Technique

• Direct Aspiration First Pass Technique (ADAPT) is recommended as first-line approach 1, 2
• ADAPT achieves higher complete reperfusion rates (OR 2.59; 95% CI 1.14-5.86), shorter procedure time (45 vs 56 minutes), and fewer periprocedural complications (4.3% vs 25.9%) compared to stent-retrievers 2
• Stent-retriever thrombectomy is reasonable as rescue therapy or when operator expertise/anatomy dictates 1, 2

Critical Imaging Requirements

• Obtain catheter-based contrast angiography before revascularization, as MRA and CTA do not reliably delineate vertebral artery origins 2, 3
• Non-contrast CT must be completed within 25 minutes of arrival for thrombolysis candidates 2
• Look for hyperdense basilar artery sign (71% sensitivity, 98% specificity; optimal density 40-42 Hounsfield units), which predicts poor outcome (OR 5.6 for mRS >2) 2

Blood Pressure Management

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

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Secondary Prevention

Anticoagulation for Vertebral Artery Thrombosis

When angiographic imaging demonstrates thrombus at the origin or extracranial segment of the vertebral artery, initiate anticoagulation and continue for a minimum of 3 months, regardless of whether thrombolytic therapy was administered. 2, 3

Antiplatelet Therapy (Post-Anticoagulation or Non-Thrombotic Etiology)

• After 3-month anticoagulation period, transition to aspirin 75-325 mg daily as first-line long-term therapy 2, 3
• Aspirin 75-100 mg combined with extended-release dipyridamole 200 mg twice daily reduces vertebrobasilar events to 5.7% versus 10.8% with placebo, offering superior protection 2, 3
• If aspirin is contraindicated (excluding active bleeding), clopidogrel 75 mg daily is preferred over aspirin alone 2, 3
• Ticlopidine 250 mg twice daily shows superiority to aspirin for symptomatic posterior circulation disease, though limited by adverse effects 2, 3

Timing Antiplatelet Therapy After Hemorrhagic Transformation

• For lower-grade hemorrhagic transformation (HI1): initiate antiplatelet therapy within 24-48 hours after confirming no bleeding progression 3
• For higher-grade hemorrhagic transformation (HI2, PH1, PH2): delay antiplatelet therapy for 7-10 days 3

Atrial Fibrillation

• Oral anticoagulation is recommended over no antithrombotic therapy, aspirin alone, or aspirin-clopidogrel combination 3
• Initiate oral anticoagulation within 1-2 weeks after stroke onset 3

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Management of Cerebellar Stroke Complications

Monitoring and Recognition

• Approximately 25% of cerebellar stroke patients develop mass effect leading to rapid deterioration; among those progressing to coma, 85% die without surgical intervention 2
• Serial neuroimaging during the first 2 days is essential; mass effect typically peaks on day 3 but may occur throughout the first week 2
• Up to 20% develop hydrocephalus from ventricular or aqueductal obstruction 2

Surgical Intervention

• Early suboccipital craniectomy with durotomy and duraplasty is recommended for significant mass effect or hydrocephalus 2
• External ventricular drain alone carries risk of upward herniation and persistent brainstem compression 2
• Approximately 50% of patients progressing to coma achieve favorable outcomes with suboccipital decompression 2
• Conservative measures (head elevation, osmotic diuretics, hyperventilation) provide only transient benefit and should not replace surgical decompression when indicated 2

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Role of Adjunctive Tirofiban

Add-on antithrombotic treatment including tirofiban shows no significant benefit in posterior circulation strokes overall (pooled OR 1.02; 95% CI 0.77-1.35) 1, 5

Specific Indications for Tirofiban

• Consider tirofiban (0.25-1 mg intra-arterial bolus followed by 0.1 μg/kg/min IV for 12-24 hours) only for: 1, 5
  • Emergency stenting or angioplasty for intracranial atherosclerotic disease
  • Presumed endothelial damage during multiple thrombectomy passes
  • Instant reocclusion observed during procedure
  • Severe in situ atherosclerosis with high reocclusion risk

Critical Safety Warning

• Combining GP IIb/IIIa inhibitors with IV alteplase increases symptomatic intracranial hemorrhage from 1.6% to 4.3% 5
• Maintain blood pressure ≤180/105 mmHg during and 24 hours after tirofiban administration 5

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Common Pitfalls to Avoid

• Posterior circulation strokes are frequently missed due to non-specific symptoms (dizziness, vertigo, nausea) and low NIHSS scores that belie devastating potential 2, 6
• Patients can have NIHSS score of 0 with only headache and vertigo yet still harbor basilar artery occlusion 2
• Door-to-needle time is significantly longer for posterior circulation strokes due to delayed recognition 2
• Do not delay IV tPA for vascular imaging in patients within the treatment window 2
• Avoid immediate reinstitution of antiplatelet therapy in higher-grade hemorrhagic transformation 3
• Do not unnecessarily delay antiplatelet therapy for minor hemorrhagic transformations, as this increases recurrent ischemic event risk 3

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Prognostic Factors

• Mortality in basilar artery occlusion ranges 45-86% without recanalization 2
• Predictors of poor outcome: older age, higher NIHSS, lack of recanalization, atrial fibrillation, intracranial hemorrhage, pc-ASPECTS ≤8 2
• Embolic strokes fare worse than in situ atherosclerosis 2
• Older age is an independent predictor of poorer outcome 2