Mechanical thrombectomy (MT) has revolutionized stroke care, becoming the standard treatment for acute ischemic stroke caused by large vessel occlusion (LVO). This evidence-based guide provides clinicians with the latest recommendations, techniques, and management strategies to optimize patient outcomes.
Key Update (June 2025): New evidence from ANGEL-TNK and PEARL trials demonstrates benefits of intra-arterial thrombolysis post-thrombectomy. Extended time windows now supported by SELECT2 and ANGEL-ASPECT trials for large core infarcts.
Epidemiology and Clinical Impact
Large vessel occlusions (LVOs) account for approximately 30% of acute ischemic strokes and are a leading cause of severe disability and mortality worldwide. LVOs in the anterior circulation (internal carotid artery and proximal M1 segment of middle cerebral artery) are responsible for the most devastating strokes [3][7].
Prevalence
30-40 patients per 100,000 annually have clots eligible for thrombectomy [3]
Time Sensitivity
Every 10-minute delay reduces disability-free life by 40 days [6]
Treatment Gap
Only 8.4% of eligible patients received MT in 2018 [6]
Current Indications and Guidelines
Based on the 2019 AHA/ASA guidelines and recent evidence updates, mechanical thrombectomy indications have expanded significantly [5][9].
| Time Window | Evidence Level | Key Criteria | Recommendation Class |
|---|---|---|---|
| 0-6 hours | Level A | Prestroke mRS 0-1, ICA/M1 occlusion, age ≥18, NIHSS ≥6, ASPECTS ≥6 | Class I |
| 6-16 hours | Level A | DAWN/DEFUSE-3 eligibility (imaging mismatch) | Class I |
| 16-24 hours | Level B-R | DAWN eligibility criteria | Class IIa |
| 0-24 hours (Large Core) | Level B-R | ASPECTS 3-5 (SELECT2, ANGEL-ASPECT) | Class IIb |
Clinical Note: Recent trials have expanded MT eligibility to include carefully selected patients with pre-stroke mRS >1, M2/M3 occlusions, and posterior circulation LVOs [4][5]. Age alone should not exclude patients from treatment consideration.
Evidence Base: Landmark Trials
MR CLEAN Trial
The first positive thrombectomy trial showing MT improved functional outcomes (32.6% vs 19.1% mRS 0-2) with NNT=7.4 [7]
HERMES Meta-analysis
Pooled data from 5 trials confirmed MT benefit across age groups with NNT=2.6 for reduced disability [7]
DAWN Trial
Extended window to 24 hours with imaging selection (49% vs 13% functional independence) [9]
SELECT2 Trial
MT benefit for large core infarcts (ASPECTS 3-5) with 20% absolute increase in functional independence [9]
ANGEL-TNK & PEARL
Intra-arterial thrombolysis post-MT improved outcomes (40.5% vs 26.4% mRS 0-1) without increasing hemorrhage risk [2]
Technical Approaches
Stent Retriever Thrombectomy
The original MT technique uses self-expanding nitinol stents to engage and remove thrombi:
- Microwire and microcatheter advanced beyond occlusion
- Stent retriever deployed and integrated with thrombus
- Stent withdrawn under continuous aspiration
- First-line approach in early landmark trials [7]
Direct Aspiration (ADAPT)
Aspiration-first approach using large-bore catheters:
- Large-bore catheter advanced to thrombus face
- Continuous aspiration applied via syringe or pump
- Catheter withdrawn with thrombus engaged
- Comparable efficacy to stent retrievers [1][7]
Combined Techniques
Hybrid approaches optimize first-pass efficacy:
- Stent retriever deployed through aspiration catheter
- Continuous aspiration during stent retrieval (SAVE technique)
- Higher first-pass reperfusion rates (up to 60%)
- Preferred approach in many high-volume centers [7]
Technical Tip: For distal and medium vessel occlusions (MeVOs), smaller stent retrievers (3-4mm) and specialized microcatheters have shown promising results with recanalization rates comparable to LVOs [1].
Special Populations
Elderly Patients (≥80 years)
MT beneficial but lower functional independence rates (20-30% vs 45-55% in younger). Key predictors: pre-stroke mRS, ASPECTS, successful recanalization [4]
Pre-stroke Disability
Patients with mRS 2-3 may return to baseline function (24-30%) despite higher mortality. MT superior to medical management in extended window [4]
Large Core Infarction
SELECT2 and ANGEL-ASPECT show MT benefit for ASPECTS 3-5 with 20% absolute increase in functional independence [9]
Posterior Circulation
MT reasonable despite limited RCT evidence. BASICS trial suggests benefit in severe strokes (NIHSS ≥10) [5][9]
Post-Thrombectomy Management
Blood Pressure Control
Optimal BP targets vary by reperfusion status:
| Reperfusion Status | SBP Target | Evidence Level |
|---|---|---|
| Successful (TICI 2b-3) | 120-140 mmHg | Level B-R [8] |
| Incomplete (TICI 0-2a) | 140-180 mmHg | Level C-LD [8] |
| ICAD-related LVO | 140-160 mmHg | Expert Consensus |
Complication Management
- Hemorrhagic Transformation: Reverse anticoagulation, control BP <140 mmHg, consider platelet transfusion if on antiplatelets [7]
- No-Reflow Phenomenon: Consider intra-arterial vasodilators or glycoprotein IIb/IIIa inhibitors [2][9]
- ICAD-related Reocclusion: Low-dose tirofiban infusion (500-750 µg) or emergency angioplasty/stenting [9]
Access and Systems of Care
Significant disparities exist in MT access, with only 27.7% of rural patients initially presenting at EVT-capable centers versus 69.5% of urban patients [6].
Geographic Barriers
One-third of US population beyond 60-minute drive to EVT center. Air ambulance access increases coverage to 62.3% [6]
Prehospital Triage
LVO screening scales (RACE, CPSSS, FAST-ED) have 50-70% specificity. Field triage to EVT centers recommended within 30-minute additional transport time [6]
Telemedicine Solutions
Tele-stroke increases thrombolysis rates and may improve LVO detection. AI-assisted CTA interpretation enhances diagnostic accuracy [6]
System Improvement: A 10% increase in EVT-capable hospitals could extend 30-minute access to an additional 10% of the US population. However, maintaining procedural volume >50 cases/year is crucial for outcomes [6].
Future Directions
Extended Time Windows
MR CLEAN-LATE trial supports MT up to 24 hours using NCCT/CTA selection without advanced imaging [9]
Adjunctive Therapies
ANGEL-TNK and PEARL trials show intra-arterial tenecteplase/alteplase post-MT improves outcomes without increasing hemorrhage [2]
Neuroprotection
Combining MT with nerinetide or remote ischemic conditioning may further improve outcomes [9]
AI Integration
Machine learning algorithms for rapid LVO detection and outcome prediction are in development [6]
References
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Endovascular thrombectomy after large-vessel ischaemic stroke: a meta-analysis of individual patient data from five randomised trialsLancet. 2016;387(10029):1723-31View Abstract
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Thrombectomy 6 to 24 Hours after Stroke with a Mismatch between Deficit and InfarctN Engl J Med. 2018;378(1):11-21View Abstract
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Mechanical Thrombectomy for All LVO - Recent Evidence to Expand Current GuidelinesScientific Archives of Neurology. 2024View Abstract
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Blood Pressure Management After Mechanical ThrombectomyEuropean Stroke Organisation. 2023View Abstract
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Intra-arterial Tenecteplase Thrombolysis After Successful Endovascular TherapyPresented at ISC 2025View Abstract