What is the best approach for thrombectomy in patients with acute ischemic stroke due to middle cerebral artery (MCA) occlusion?

Mechanical Thrombectomy for Acute Ischemic Stroke with MCA Occlusion

For acute ischemic stroke with MCA M1 occlusion, mechanical thrombectomy using stent retrievers is the definitive treatment and should be performed within 6 hours of symptom onset (or up to 24 hours in selected patients meeting DAWN/DEFUSE-3 criteria), with the technical goal of achieving TICI 2b/3 reperfusion. 1, 2

Patient Selection Criteria for M1 Occlusions (0-6 Hours)

Class I (Strongest) Recommendations for thrombectomy include: 1, 2

• Age ≥18 years with pre-stroke mRS 0-1 2
• NIHSS score ≥6 1, 2
• ASPECTS ≥6 1, 2
• Causative occlusion of ICA or MCA M1 segment confirmed on non-invasive angiography 1, 2
• Treatment initiation (groin puncture) within 6 hours of symptom onset or last known well 1, 2

Important: Age is not an absolute contraindication. The HERMES collaboration demonstrated favorable outcomes in patients ≥80 years old (common OR 3.68; 95% CI 1.95-6.92), though benefits in patients ≥90 years remain unclear. 1

Extended Time Window (6-24 Hours)

For patients presenting 6-16 hours after last known normal: 2

• Thrombectomy is recommended if they meet DAWN or DEFUSE-3 eligibility criteria 1, 2
• Requires advanced imaging (CTP or DW-MRI) demonstrating salvageable tissue with mismatch between ischemic core and clinical deficits or hypoperfusion area 2

For patients presenting 16-24 hours after last known normal: 2

• Thrombectomy may be reasonable if they meet DAWN criteria specifically 1, 2
• Strict adherence to these criteria is mandatory 3

M2 Occlusions: A More Nuanced Approach

Thrombectomy for M2 occlusions is a Class IIb recommendation ("may be reasonable"), indicating uncertain but possible benefit. 1, 3

The evidence base is weaker than for M1 occlusions: 1, 3

• HERMES meta-analysis showed favorable direction of effect but non-significant adjusted OR (1.28; 95% CI 0.51-3.21) 1, 3
• Pooled data from SWIFT/STAR/DEFUSE 2/IMS III demonstrated reperfusion associated with excellent outcomes (mRS 0-1; OR 2.2; 95% CI 1.0-4.7) 1, 3
• A 2018 meta-analysis of 1,080 M2 patients showed 59% functional independence and 81% recanalization rates, though with potentially increased hemorrhage risk 4

Decision factors for M2 thrombectomy should include: 3

• Clinical severity (higher NIHSS favors intervention)
• Imaging findings (larger territory at risk)
• Technical accessibility of the occlusion 3

Technical Approach and Device Selection

Stent retrievers are the preferred first-line devices (Class I recommendation). 1

Specific technical recommendations: 1, 2

• Use stent retrievers (Solitaire, Trevo) over older MERCI devices 1
• Consider proximal balloon guide catheter or large-bore distal-access catheter rather than cervical guide catheter alone 1
• Target TICI 2b/3 reperfusion as the technical goal to maximize functional outcomes 1, 5, 2
• Mean time to recanalization with modern stent retrievers is approximately 47-60 minutes 6, 7

For refractory occlusions after initial stent retriever attempts: 8

• Double stent retriever technique achieved 80% recanalization (TICI 2b/3) in cases refractory to standard single-device thrombectomy 8
• Salvage intra-arterial fibrinolysis may be reasonable if completed within 6 hours 1

Integration with IV Thrombolysis

Critical workflow principles: 1, 2

• Eligible patients should receive IV alteplase even if thrombectomy is planned 1, 2
• Do NOT delay or withhold IV thrombolysis while arranging thrombectomy 3, 2
• Do NOT observe patients after IV alteplase to assess response before pursuing thrombectomy—this is explicitly not recommended (Class III) 1, 2
• Pretreatment with IV alteplase is not required for thrombectomy benefit (HERMES showed treatment effect OR 2.43; 95% CI 1.30-4.55 in patients not receiving IV alteplase) 1

Management of Tandem Lesions

For patients with cervical carotid stenosis/occlusion plus intracranial occlusion: 5, 2

• Thrombectomy can be performed 2
• Angioplasty and stenting of proximal cervical atherosclerotic stenosis during thrombectomy may be considered, though benefit is uncertain (Class IIb) 1
• Clinical trials used this approach in only 40% of tandem lesion cases 5

Common Pitfalls to Avoid

Time-related errors: 1, 2

• Delaying catheter angiography to observe IV thrombolysis response 1, 2
• Failing to use advanced imaging for extended window patients 2

Patient selection errors: 3, 2

• Applying extended window criteria loosely—DAWN/DEFUSE-3 criteria must be strictly followed 3, 2
• Excluding elderly patients reflexively—age ≥80 shows benefit, though consider comorbidities 1

Technical errors: 1, 5

• Accepting TICI 2a or lower as adequate—target should be TICI 2b/3 1, 5
• Using outdated devices when stent retrievers are available 1

Post-Procedure Management

Immediate assessment: 5

• Confirm TICI 2b/3 recanalization 5
• Maintain systolic blood pressure 130-150 mmHg to prevent hemorrhagic transformation 5

Antithrombotic therapy: 5

• Rule out hemorrhagic transformation before initiating anticoagulation for cardioembolic sources 5
• Consider dual antiplatelet therapy initially for atherosclerotic disease, transitioning to single agent long-term 5
• Avoid premature anticoagulation in large infarcts due to hemorrhage risk 5

Systems of Care Requirements

Facility requirements: 2

• Immediate access to cerebral angiography and qualified interventionalists 2
• Defined credentialing criteria for operators performing endovascular procedures 2
• Capability for emergency non-invasive intracranial vascular imaging at primary stroke centers to facilitate appropriate transfers 1

Transport protocols: 1, 2

• Rapid transport to closest certified primary or comprehensive stroke center 1, 2
• May involve air medical transport and hospital bypass in some instances 1