What is the recommended initial treatment for acute stroke after intracranial artery dissection, specifically regarding intravenous thrombolysis with tissue plasminogen activator (tPA)?

Intravenous Thrombolysis for Acute Stroke After Intracranial Artery Dissection

Administer standard-dose IV tPA (0.9 mg/kg, maximum 90 mg) for acute ischemic stroke caused by intracranial artery dissection if the patient presents within 3 hours of symptom onset and meets standard eligibility criteria, as arterial dissection is not listed as a contraindication in established guidelines. 1

Treatment Algorithm

Within 3 Hours of Symptom Onset

• Administer IV tPA 0.9 mg/kg (maximum 90 mg) as 10% bolus followed by 90% infusion over 60 minutes if no standard contraindications exist 1
• The presence of intracranial artery dissection itself does not constitute an absolute contraindication to thrombolysis 1
• Door-to-needle time should be within 60 minutes of hospital arrival 1

Between 3-4.5 Hours of Symptom Onset

• Consider IV tPA with additional ECASS III exclusion criteria: exclude patients >80 years old, those taking oral anticoagulants regardless of INR, baseline NIHSS >25, imaging evidence of ischemic injury involving more than one-third of MCA territory, or history of both stroke and diabetes 1
• The symptomatic intracranial hemorrhage risk increases to approximately 7-8% in this time window 2, 3

Beyond 4.5 Hours

• Do not administer IV tPA - treatment beyond this window is not recommended 1
• Consider intra-arterial thrombolysis for selected patients with major stroke due to middle cerebral artery occlusion within 6 hours, though this requires specialized expertise and facilities 1

Evidence Supporting tPA Use in Dissection

Registry data demonstrates that patients with extracranial internal carotid artery occlusion (including dissection) treated with standard tPA protocols within 4.5 hours had symptomatic ICH rates of 8%, mortality of 11%, and good functional outcomes in 60% of cases 2. This risk profile is comparable to the general acute ischemic stroke population treated with tPA 1.

The standard inclusion and exclusion criteria from the NINDS trial do not list arterial dissection as a contraindication 1. The primary contraindications focus on bleeding risk factors such as recent surgery, prior intracranial hemorrhage, uncontrolled hypertension, and coagulopathy 1.

Dosing Considerations

• Use the standard 0.9 mg/kg dose (maximum 90 mg) - lower doses have been associated with worse functional outcomes 4
• Asian populations should receive the same 0.9 mg/kg dose, as lower doses (0.5-0.7 mg/kg) resulted in significantly less excellent recovery (modified Rankin Scale 0-1: 41.89% vs 53.83%, OR=0.58, P=0.031) without reducing symptomatic ICH risk 4

Critical Post-Thrombolysis Management

Blood Pressure Control

• Maintain systolic BP <180 mmHg and diastolic BP <105 mmHg during and after tPA infusion 5
• Emergency antihypertensive treatment is warranted if BP exceeds these thresholds to reduce hemorrhagic transformation risk 5
• Avoid excessive hypotension that could compromise cerebral perfusion 5

Hemorrhage Monitoring

• Obtain CT scan 24 hours after tPA administration before initiating any antithrombotic therapy 5
• Any neurological deterioration should prompt immediate repeat imaging 5
• Symptomatic intracranial hemorrhage occurs in approximately 6.4% of tPA-treated patients 5

Medication Restrictions

• Avoid all antithrombotic drugs (including aspirin) for 24 hours after tPA administration 1, 5
• Once hemorrhage is excluded on 24-hour imaging, initiate aspirin 160-325 mg immediately 1, 5

Common Pitfalls to Avoid

• Do not withhold tPA solely because of arterial dissection - dissection is not a contraindication in established guidelines 1
• Do not use reduced tPA doses - standard 0.9 mg/kg dosing provides superior outcomes without increasing hemorrhage risk 4
• Do not delay treatment for extensive vascular imaging - if CT excludes hemorrhage and shows no contraindications, proceed with tPA while obtaining additional imaging 1
• Do not start antiplatelet therapy before the 24-hour exclusionary CT scan - this significantly increases bleeding risk 1, 5
• Do not exceed the 4.5-hour treatment window - efficacy beyond this time is not established 1

Alternative Approaches

If IV tPA is contraindicated or the patient presents beyond 4.5 hours but within 6 hours with proximal cerebral artery occlusion, intra-arterial thrombolysis may be considered at experienced stroke centers with immediate access to cerebral angiography and qualified interventionalists 1. However, the availability of intra-arterial therapy should not preclude IV tPA administration in otherwise eligible patients 1.

Mechanical thrombectomy devices have been used for acute stroke but remain under investigation, and current evidence suggests IV tPA alone over combination IV/IA approaches for most patients 1.