This document provides guidance on patient selection for mechanical thrombectomy in acute ischemic stroke. It discusses key factors such as time from last known normal, vessel occlusion location, imaging findings on non-contrast CT and CTA/CTP. Patients within 6 hours should have an NIHSS ≥6, ASPECTS ≥6, pre-stroke mRS 0-1 and occlusion of the ICA or M1 segment. Between 6-24 hours, perfusion imaging can identify patients with clinical-radiological mismatch. The DAWN and DEFUSE3 trials expanded the window showing benefit for thrombectomy out to 16-24 hours in selected patients. Special scenarios like posterior circulation strokes and patients with preexisting disability are also reviewed. Mechanical

1. Patient Selection for Stroke
Mechanical Thrombectomy
MT2020+ Hands On Skill Workshop
Gillian L. Gordon Perue, MB;BS, DM, FAHA, FAAN
Assistant Professor, Vascular Neurology
Chief, Neurology, Jackson South Medical Center
Director, Stroke Program, Jackson South Medical Center
Chief, Neurology, Jackson West Medical Center
MT2020+ Anglo-Caribbean US Liaison
Jan 24th, 2022

2. Conflict of Interest
Financial disclosures:
Transitions of Stroke Care Study
Florida State Registry
Florida Coverdell Grant
Off Label use: none

3. Objectives
Pathophysiology of Stroke
Patient selection < 6 hours
Patient selection 6-12 hours
Special Cases

4. Pathophysiology of Acute Ischemic Stroke
• The disruption of blood supply triggers a process which leads to cell
death
• 1.9 million neurons lost per minute without adequate
reperfusion
• Time = Brain
• Reperfusion Therapy is central part of our acute strategy
• Intravenous chemical lysis
• Intraarterial Chemical lysis
• Mechanical Thrombectomy
Kuriakose, Diji, and Zhicheng Xiao. “Pathophysiology and Treatment of Stroke: Present Status and Future
Perspectives.” International journal of molecular sciences vol. 21,20 7609. 15 Oct. 2020, doi:10.3390/ijms21207609
Saver JL. Time is brain--quantified. Stroke. 2006 Jan;37(1):263-6. doi: 10.1161/01.STR.0000196957.55928.ab. Epub 2005 Dec 8.
PMID: 16339467.

5. Acute Stroke due to Large Intracranial Vessel occlusion (LVO)
LVO Stroke
•10% of all Acute Ischemic Stroke will have large
vessel occlusion.
Disproportionate burden of disease
and worse outcomes
60-80% will die or not regain
independence despite receiving ivtpa.
Rai AT, et al. J NeuroIntervent Surg 2016;0:1–5. doi:10.1136/neurintsurg-2016-012515

6. Acute endovascular Thrombectomy
• Acute Endovascular intervention for acute large vessel ischemic stroke is
now the standard of care.
• Based on 6 randomized control studies that showed
• Improved functional outcomes over ivtpa
• For the first time a Mortality Benefit with intervention

7. Code Stroke Process helps identify the Large Vessel Occlusion
Copyright © 2017 American Academy of Neurology 7

8. Identifying the Ideal Patient?
• Ideal Candidate = Target Vessel + Salvageable Brain Tissue

9. Acute Ischemic changes on CT
• 60% of CT are normal in the first hour.
Insular ribbon sign
Hyperdense vessel sign
Sulcal effacement

10. Hyperdense artery sign
• CT brain alone is not enough to
identify LVO stroke
– Site of occlusion
– Thickness of CT
– Sensitivity 52.4% (95% CI
41.2-63.4%).
– Specificity 94.9% (92.5-96.6%)
• CTA done during the stroke alert is
the gold standard
• MRA can be used but at times
contributes to delays
Mair G, Boyd EV, Chappell FM, von Kummer R, Lindley RI, Sandercock P, Wardlaw JM; IST-3 Collaborative Group.
Sensitivity and specificity of the hyperdense artery sign for arterial obstruction in acute ischemic stroke. Stroke. 2015
Jan;46(1):102-7. doi: 10.1161/STROKEAHA.114.007036. Epub 2014 Dec 4. PMID: 25477225; PMCID: PMC4338528.

11. Vessel Imaging per the Guidelines
• 2013 AHA/ASA Guidelines
A noninvasive intracranial vascular study is strongly recommended during the initial imaging evaluation of the acute stroke
patient if either intra-arterial fibrinolysis or mechanical thrombectomy is contemplated for management but should not delay
intravenous rtPA if indicated (Class I; Level of Evidence A). (Revised from the 2009 imaging scientific statement)
• Reaffirmed in 2019 updated AHA/ASA
• CTA for the detection of intracranial occlusions
– Sensitivity 92% and 100% and specificity 82% and 100%,
– positive predictive value of 91% to 100%.
• MRI and MRA can be used, CTA has greater accuracy
• Landmark trials used CTA as preferred imaging modality

12. Identifying the Ideal Patient?
• Ideal Candidate = Target Vessel + Salvageable Brain Tissue

13. Time
• Last time known well (LKW)
– This is a very specific definition in stroke
– Refers to the last time patient was noted to be using that neurological function
– This is different from the time of symptom discovery in some cases.
– Patients who wake up with symptoms are said to be last seen well usually before they went to
sleep.
• Patients can be considered candidates for MT within 24 hours of LKW.

14. AHA/ASA Mechanical Thrombectomy (6 hours)
• Patients should receive mechanical thrombectomy with
a stent retriever if they meet all the following criteria:
• pre-stroke mRS score of 0 to 1;
• causative occlusion of the internal carotid artery or MCA
segment 1 (M1);
• age ≥18 years;
• NIHSS score of ≥6;
• ASPECTS of ≥6; and
• treatment can be initiated (groin puncture) within 6
hours of symptom onset
• No need for additional Neuroimaging such as perfusion
scan
• Patients eligible for IV alteplase should receive IV alteplase
even if EVTs are being considered

17. AHA/ASA Mechanical Thrombectomy (6 hours)
• Patients should receive mechanical thrombectomy
with a stent retriever if they
• causative occlusion of the internal carotid
artery or MCA segment 1 (M1);
• ASPECTS of ≥6; and
• No need for additional Neuroimaging such as perfusion
scan
• New Studies updates these criteria expect that
guidelines will be updated as well

18. Courtesy of Thanh Nguyen MSD Boston Medical Center 2016
Efficacy of Mechanical Thrombectomy with 6 hours LKW
• NNT 1:4
• NNT In MI 1:18

19. Attenuation–time curve for a given region of interest.
Stevan Christopher Wing, and Hugh S Markus Pract Neurol
2019;19:136-142
©2019 by BMJ Publishing Group Ltd
Time >6 hours or is unknown
• Imaging becomes the best predictor of the penumbra
• CT based
• MRI based
Clinical radiological mismatch

20. A 73-year-old right-handed man with a history of hypertension and myocardial infarction presented 80 min after
experiencing a sudden onset of left arm and leg weakness while gardening.
Stevan Christopher Wing, and Hugh S Markus Pract Neurol
2019;19:136-142
©2019 by BMJ Publishing Group Ltd

21. Extended window eligibility
General Inclusion Clinical/Radiological Mismatch
Age 18 Confirmed tICA or M1 occlusion AND
- NIHSS ≥10
- Pre-mRS 0-1
RAPID CTP/DWI CIM:
A. 80 y/o:
1. NIHSS 10 + core <21cc
. RAPID CTP/DWI CIM
B <80 y/o:
2. NIHSS 10 + core <31cc
3. NIHSS 20 + core <51cc
General Inclusion RadiologicalMismatch
Age18-90
NIHSS ≥6
Pre-strokemRS 0-2
Confirmed tICA or M1 occlusion AND
RAPID Mismatch
Core < 70 ml
Ratioof ischemictissueto
infarct≥1.8 Penumbra of
≥ 15 ml

22. Example of DEFUSE

25. The 55-year-old woman in figure 2 was referred for thrombectomy.
Stevan Christopher Wing, and Hugh S Markus Pract Neurol
2019;19:136-142
©2019 by BMJ Publishing Group Ltd

26. Results of DAWN and DEFUSE3

27. AHA/ASA Guidelines
Patients who have Wake up Stroke or LKW> 6 hours
• In selected patients with AIS within 6 to 16 hours of last known normal who
have LVO in the anterior circulation and meet other DAWN or DEFUSE 3
eligibility criteria, mechanical thrombectomy is recommended.
• In selected patients with AIS within 6 to 24 hours of last known normal who
have LVO in the anterior circulation and meet other DAWN eligibility criteria,
mechanical thrombectomy is reasonable.

28. Solitaire stent retriever

29. Special Scenarios
64-year-old white man with history of hypertension, type 2 diabetes mellitus on oral therapy
Stroke in 2012 with residual L sided weakness, another in 2014 with residual left sided weakness and continued tobacco abuse.
At his baseline he walks with a cane on using the left hand.
He has had intermittent bouts of dizziness since his last stroke. Initially rescue told e was last seen well at 0200 hr. However, we called and spoke with his wife. At 10:30
pm he ate dinner, at 12:30 am he began complaining of not feeling well. He vomited at that time, vomited again at 2 am so rescue was called. Since being here he has
become more lethargic.
Presented at 0309 hr

30. Special Scenarios
• LVO studies are all anterior circulation
• Benefits in posterior circulation

31. Special Scenarios
• LVO studies are all anterior circulation
• Benefits in posterior circulation
Solla DJF, Argolo FC, Budohoski KP, Kolias AG, Caldas JGMP, Oliveira-Filho J. Is more evidence needed for
thrombectomy in basilar artery occlusion? The BASICS and BEST meta-analytical approaches. Stroke Vasc
Neurol. 2021 Dec;6(4):671-672. doi: 10.1136/svn-2020-000701. Epub 2021 May 3. PMID: 33941641; PMCID:

32. Second Scenario
Patients with preexisting disability
-both neurological vs non-neurological
-more likely to have a poor outcome at 90 days
-MT remains their best chance at a good outcome

33. Case
Age 41 yo R handed M
PMH Epilepsy
ADLS: independent, works
Presented to us at: 23:20 hr
Symptoms: LKW 8 AM
Had breakthrough seizure at 6 am and didn’t
return to his baseline completely, went to OSH,
discharged and came back to Jackson South
because of L arm and leg plegia
Investigations:
CTH with R MCA stroke, CTA with R M2
occlusion NIHSS 7 CTB ASPECT 9
IV tPA no OOW
CTA R M2 proximal occlusion
CTP perfusion deficit
MRS 0
COVID POSITIVE

34. 15 hours after LKW

36. Gordon Perue 1/18/2022
All patients presenting within 24 hours of LKW
NIHSS and Stat CT brain
Hemorrhage Normal or no acute changes
LKW 0-4.5 hours LKW 6- 24 hours LKW Unknown/Wake up
Stat CTA Head and Neck
Stat CTA Head and Neck
CT perfusion
Mechanical Thrombectomy
Acute Stroke Medical Management
LKW 4.5- 6 hrs.
iv rtPA if indicated
If LVO+
MT if target vessel and
penumbra
iv rtPA if indicated
MT if target vessel and penumbra

37. References
• Guidelines for the prevention of stroke in patients with Stroke and Transient Ischemia Attack AHA/ASA Stroke 2014;45:2236
• 2018 Early Guidelines for the management of patients with acute Ischemic Stroke. AHA/ASA Stroke 2018 Mar;49(3):e46-e110
• Continnuum Neurology 2017; 23(1) 111-132
• Lancet. 2003 Jan 11;361(9352):107-16.Analysis of pooled data from the randomised controlled trials of endarterectomy for symptomatic carotid stenosis. Rothwell PM1,
Eliasziw M, Gutnikov SA, Fox AJ, Taylor DW, Mayberg MR, Warlow CP, Barnett HJ; Carotid Endarterectomy Trialists' Collaboration.
• Neurol Clin Pract. 2014 Oct;4(5):386-393.Cryptogenic stroke: A diagnostic challenge. Yaghi S1, Elkind MS.
• Kuriakose, Diji, and Zhicheng Xiao. “Pathophysiology and Treatment of Stroke: Present Status and Future Perspectives.” International journal of molecular sciences vol.
21,20 7609. 15 Oct. 2020, doi:10.3390/ijms21207609
• Saver JL. Time is brain--quantified. Stroke. 2006 Jan;37(1):263-6. doi: 10.1161/01.STR.0000196957.55928.ab. Epub 2005 Dec 8. PMID: 16339467.
• Mair G, Boyd EV, Chappell FM, von Kummer R, Lindley RI, Sandercock P, Wardlaw JM; IST-3 Collaborative Group. Sensitivity and specificity of the hyperdense artery sign
for arterial obstruction in acute ischemic stroke. Stroke. 2015 Jan;46(1):102-7. doi: 10.1161/STROKEAHA.114.007036. Epub 2014 Dec 4. PMID: 25477225; PMCID:
PMC4338528.
• Stevan Christopher Wing, and Hugh S Markus Pract Neurol 2019;19:136-142
• Solla DJF, Argolo FC, Budohoski KP, Kolias AG, Caldas JGMP, Oliveira-Filho J. Is more evidence needed for thrombectomy in basilar artery occlusion? The BASICS and BEST
meta-analytical approaches. Stroke Vasc Neurol. 2021 Dec;6(4):671-672. doi: 10.1136/svn-2020-000701. Epub 2021 May 3. PMID: 33941641; PMCID: PMC8717765.
• Nogueira RG, Jadhav AP, Haussen DC, Bonafe A, Budzik RF, Bhuva P, Yavagal DR, Ribo M, Cognard C, Hanel RA, Sila CA, Hassan AE, Millan M, Levy EI, Mitchell P, Chen M,
English JD, Shah QA, Silver FL, Pereira VM, Mehta BP, Baxter BW, Abraham MG, Cardona P, Veznedaroglu E, Hellinger FR, Feng L, Kirmani JF, Lopes DK, Jankowitz BT,
Frankel MR, Costalat V, Vora NA, Yoo AJ, Malik AM, Furlan AJ, Rubiera M, Aghaebrahim A, Olivot JM, Tekle WG, Shields R, Graves T, Lewis RJ, Smith WS, Liebeskind DS,
Saver JL, Jovin TG; DAWN Trial Investigators. Thrombectomy 6 to 24 Hours after Stroke with a Mismatch between Deficit and Infarct. N Engl J Med. 2018 Jan 4;378(1):11-
21. doi: 10.1056/NEJMoa1706442. Epub 2017 Nov 11. PMID: 29129157.
• Albers GW, Marks MP, Kemp S, Christensen S, Tsai JP, Ortega-Gutierrez S, McTaggart RA, Torbey MT, Kim-Tenser M, Leslie-Mazwi T, Sarraj A, Kasner SE, Ansari SA, Yeatts
SD, Hamilton S, Mlynash M, Heit JJ, Zaharchuk G, Kim S, Carrozzella J, Palesch YY, Demchuk AM, Bammer R, Lavori PW, Broderick JP, Lansberg MG; DEFUSE 3
Investigators. Thrombectomy for Stroke at 6 to 16 Hours with Selection by Perfusion Imaging. N Engl J Med. 2018 Feb 22;378(8):708-718. doi: 10.1056/NEJMoa1713973.
Epub 2018 Jan 24. PMID: 29364767; PMCID: PMC6590673.

38. Questions
Please feel free to contact me for Questions
Gillian L. Gordon Perue, MB;BS, DM, FAHA, FAAN
Assistant Professor, Vascular Neurology
University of Miami Miller School of Medicine
Chief, Neurology, Jackson South Medical Center
Director, Stroke Program, Jackson South Medical Center
Chief, Neurology, Jackson West Medical Center
ggordonperue@miami.edu
305-256-4492