What is the recommended acute and subacute management for a patient with vertebral‑artery thrombosis causing a lateral medullary (Wallenberg) infarct?

Management of Vertebral Artery Thrombosis with Lateral Medullary Infarct

For acute vertebral artery thrombosis causing lateral medullary (Wallenberg) infarct, initiate anticoagulation therapy for at least 3 months when angiographic evidence of thrombus is present in the extracranial vertebral artery, regardless of whether thrombolytic therapy was administered initially. 1

Acute Phase Management (0-24 Hours)

Reperfusion Therapy Considerations

• Intravenous alteplase (0.9 mg/kg, maximum 90 mg) should be administered within 4.5 hours of symptom onset if the patient meets eligibility criteria, with 10% given as immediate bolus and remainder over 60 minutes 2

• Endovascular thrombectomy is indicated within 12 hours if NIHSS ≥6, posterior circulation ASPECTS (pc-ASPECTS) ≥6, and age 18-89 years with confirmed vertebral or basilar artery occlusion on CTA 3, 2

• Between 12-24 hours from last known well, thrombectomy remains reasonable using the same patient selection criteria 3, 2

• Direct Aspiration First Pass Technique (ADAPT) achieves higher complete reperfusion rates (OR 2.59) and fewer periprocedural complications (4.3% vs 25.9%) compared to stent-retriever devices 2

Critical Diagnostic Requirements

• Obtain CTA or contrast-enhanced MRA immediately rather than ultrasound, as these modalities demonstrate 94% sensitivity and 95% specificity versus ultrasound's 70% sensitivity for vertebral artery stenosis 1, 4

• Catheter-based contrast angiography is required before any revascularization procedure because neither MRA nor CTA reliably delineates vertebral artery origins 1, 3, 4

• Look for the hyperdense basilar artery sign on non-contrast CT (71% sensitivity, 98% specificity for basilar occlusion), which predicts poor 6-month outcome (mRS >2, OR 5.6) 2

Blood Pressure Management

• If systolic BP >185 mmHg or diastolic >110 mmHg before thrombolysis: administer 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 titrated by 2.5 mg/h every 5-15 minutes (maximum 15 mg/h) 2

• Do not administer tPA if blood pressure cannot be reduced and maintained at systolic ≤185 mmHg and diastolic ≤110 mmHg 2

Subacute Management (3 Months)

Anticoagulation Protocol

• Anticoagulation is generally recommended for at least 3 months when angiographic evidence demonstrates thrombus at the origin or extracranial portion of the vertebral artery, whether or not thrombolytic therapy was used 1, 3, 4

• This recommendation applies specifically to acute ischemic syndromes involving vertebral artery territory with visible thrombus 1

Antiplatelet Therapy After Anticoagulation Period

• Following the 3-month anticoagulation period, transition to aspirin 75-325 mg daily as first-line long-term antiplatelet therapy 3, 4

• Aspirin plus extended-release dipyridamole (200 mg twice daily) reduces vertebrobasilar territory stroke/TIA to 5.7% versus 10.8% with placebo and represents a superior alternative to aspirin monotherapy 1, 2, 4

• If aspirin is contraindicated (excluding active bleeding), use clopidogrel 75 mg daily as a reasonable alternative 1, 3, 4

• Ticlopidine 250 mg twice daily demonstrated superiority to aspirin for secondary prevention in symptomatic posterior circulation disease, though side effects limit its use 1, 2, 4

Monitoring for Cerebellar Complications

High-Risk Period and Surveillance

• Approximately 25% of lateral medullary infarct patients develop cerebellar mass effect leading to rapid deterioration; among those progressing to coma, 85% die without surgical intervention 2

• Serial neuroimaging during the first 48-72 hours is essential because 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 Criteria

• Early suboccipital craniectomy with durotomy and duraplasty is recommended for patients developing significant mass effect or hydrocephalus 2

• External ventricular drain placement alone carries risk of upward herniation and persistent brainstem compression 2

• Approximately 50% of patients progressing to coma who receive suboccipital decompression achieve favorable functional outcomes 2

• Conservative measures (head elevation, osmotic diuretics, hyperventilation) provide only transient benefit and should not replace surgical decompression when indicated 2

Revascularization Considerations

When Medical Therapy Fails

• Revascularization (endovascular or surgical) should only be considered after medical therapy fails in patients with persistent or recurrent posterior circulation ischemic symptoms despite optimal medical management 3, 4

• Endovascular treatment carries significant risks: death (0.3%), periprocedural neurological complications (5.5%), posterior stroke (0.7%), and restenosis (26% at mean 14-month follow-up) 1, 3, 4

• Surgical options include trans-subclavian vertebral endarterectomy, vertebral artery transposition to ipsilateral common carotid artery, or reimplantation with vein graft extension 1, 4

Critical Pitfalls to Avoid

• Do not rely on NIHSS alone for posterior circulation strokes—patients can have NIHSS of 0 with only headache, vertigo, and nausea yet still harbor devastating basilar artery occlusion 2

• Do not use dual antiplatelet therapy (aspirin plus clopidogrel) routinely due to hemorrhage risk outweighing benefit 3

• Do not delay IV tPA for vascular imaging in patients within the 4.5-hour treatment window—begin tPA before transport for additional imaging or endovascular therapy 2

• Do not pursue revascularization as first-line therapy due to insufficient evidence of benefit over medical management 3, 4

• Lateral medullary syndrome presents with non-specific symptoms (dizziness 94.4%, limb ataxia 84.3%, dysarthria 44.4%) that frequently delay diagnosis compared to anterior circulation strokes 5

Long-Term Management

• Continue indefinite antiplatelet therapy after the acute anticoagulation phase with aggressive cardiovascular risk factor modification 3, 4

• Serial noninvasive imaging of extracranial vertebral arteries is reasonable to assess atherosclerotic disease progression and exclude new lesions 1, 4

• Monitor for recurrent posterior circulation symptoms including vertigo, diplopia, ataxia, bilateral sensory deficits, and syncope 4