What is the recommended treatment approach for a patient presenting with acute ischemic stroke who is a candidate for thrombectomy?

Mechanical Thrombectomy for Acute Ischemic Stroke

For patients with acute ischemic stroke due to large vessel occlusion (LVO) in the anterior circulation, mechanical thrombectomy combined with IV alteplase (if eligible) is the standard of care and should be performed within 6 hours of symptom onset, with extended windows up to 24 hours possible in carefully selected patients based on advanced imaging criteria. 1, 2

Treatment Algorithm for Thrombectomy Candidates

Initial Assessment and IV Thrombolysis (0-4.5 hours)

• Administer IV alteplase (0.9 mg/kg, maximum 90 mg) immediately if the patient presents within 4.5 hours and has no contraindications 3, 1, 4
• Give 10% as IV bolus over 1 minute, followed by 90% infused over 60 minutes 1, 4
• Blood pressure must be reduced to <185/110 mmHg before initiating alteplase 1, 4
• Do NOT delay IV thrombolysis to obtain vascular imaging or assess thrombectomy eligibility 1

Concurrent Thrombectomy Evaluation

• Obtain non-invasive angiography (CTA) immediately for patients with clinically suspected LVO 1
• Do NOT wait to evaluate the patient's response to IV alteplase before proceeding with catheter angiography for mechanical thrombectomy 1
• This represents a critical paradigm shift from older guidelines that suggested waiting 1

Thrombectomy Indications Within 6 Hours

• Perform mechanical thrombectomy for proximal anterior circulation LVO (internal carotid artery, M1 segment of middle cerebral artery) within 6 hours of symptom onset 1, 2
• Modern stent retrievers achieve recanalization rates of 72-88%, compared to near-zero with IV therapy alone for high clot burden 1
• The number needed to treat is approximately 3-4 patients for one additional good functional outcome 1
• Symptomatic intracranial hemorrhage rates are similar between thrombectomy (4.4%) and control (4.3%) groups 1

Extended Window Thrombectomy (6-24 Hours)

• For patients presenting 6-24 hours after last known well with anterior circulation LVO, use advanced imaging (CT perfusion or diffusion-weighted MRI) to identify salvageable tissue 1, 5
• The DAWN trial demonstrated a 35.5% increase in functional independence when treating patients at a median of 12.5 hours using clinical-imaging mismatch criteria 5
• The DEFUSE 3 trial showed 28% increase in functional independence at a median of 11 hours using perfusion imaging 5
• This "tissue window" approach replaces the rigid time window concept 5

Evidence Quality and Evolution

Historical Context (2003-2012)

• Early guidelines (2003) recommended against mechanical thrombectomy outside research settings due to lack of controlled data (Grade C) 3
• The 2012 CHEST guidelines suggested against mechanical thrombectomy (Grade 2C) based on limited evidence at that time 3

Paradigm Shift (2015-Present)

• Five landmark trials in 2015 (MR CLEAN, ESCAPE, SWIFT PRIME, EXTEND-IA, REVASCAT) definitively established thrombectomy superiority 1, 6, 7
• Meta-analysis showed mechanical thrombectomy significantly improves functional independence (OR 2.39,95% CI 1.88-3.04) 7
• Real-world data confirms trial results are reproducible, with 87% successful recanalization rates and only 2.6% symptomatic intracranial hemorrhage 6

Technical Considerations

Device Selection and Technique

• Second-generation stent retrievers (e.g., L5 Retriever) achieve 57-69% recanalization rates as monotherapy 8
• Combined with adjunctive intraarterial thrombolysis when needed, recanalization rates reach 69-75% 8
• Favorable clinical outcomes (modified Rankin Scale 0-2) occur in 36% of patients, significantly related to successful recanalization 8

Critical Pitfalls to Avoid

• Never withhold IV alteplase from eligible patients while arranging thrombectomy 1
• Never delay thrombectomy to assess IV alteplase response 1
• Hyperglycemia >11.1 mmol/L substantially increases hemorrhagic risk (36% symptomatic ICH rate) and should be corrected 1
• Clinically significant procedural complications occur in 5.5% of patients 8

Post-Thrombectomy Management

• Do NOT administer anticoagulants or antiplatelet agents for 24 hours after IV alteplase 4
• Monitor blood pressure every 15 minutes during and for 2 hours after alteplase, maintaining <180/105 mmHg 4
• Initiate aspirin 160-325 mg within 24-48 hours after thrombectomy (if no alteplase given) or after 24 hours (if alteplase given) 3, 9

Special Populations

Patients Ineligible for IV Alteplase

• For patients with contraindications to IV thrombolysis who present within 6 hours with proximal LVO, proceed directly to mechanical thrombectomy 3, 2
• Intraarterial thrombolysis may be considered as rescue therapy if early recanalization is not achieved 1

Patients Beyond Standard Windows

• The extended window approach (6-24 hours) requires specialized centers with advanced imaging capabilities 1, 5
• Clinical-imaging mismatch serves as a surrogate for salvageable tissue rather than relying solely on time 5