The document discusses recent evidence for mechanical thrombectomy in acute ischemic stroke. It summarizes several recent randomized controlled trials that compared mechanical thrombectomy using stent retrievers to standard medical therapy alone. The trials showed that mechanical thrombectomy significantly improved rates of reperfusion and functional independence, with absolute increases in good clinical outcomes ranging from 13.5% to 31.4%. Mechanical thrombectomy also reduced mortality in some trials. Based on these results, international guidelines now recommend endovascular therapy with stent retrievers for appropriately selected patients within 6 hours of stroke onset.

1. Recent evidence for mechanical thrombolysis
Vipul Gupta
Neurointerventional Surgery
(Interventional Neuroradiology)
Institute of Neurosciences
Medanta the Medicity

2. Acute stroke :
Penumbra and Treatment Options
0
10
20
30
min
CBF(ml/100g/min)
300 9060 4120 5 6 24 48h
Infarct-
threshold
Penumbra
Vital tissue
InfarctSingle cell
necrosis
3

3. IV tPA- indications
; ASA/AHA guidelines
Stroke - 2013
Less than 10% patients are eligible

4. ECASS 3
52.4% vs. 45.2%; OR, 1.34; 95% CI,1.02 to 1.76; P=0.04.
IV tPA beyond 3-hours….

5. 3- 6 hours
PWI/ DWI > 1.2
Non significant
difference in
good outcome

7. • 53 studies, 2066 patients
• Sp.- 24%, IV tPA- 46%, IA- 64%, Mechanical- 84%
• Good outcome more in recanalized patients (OR- 4.4)
• Less mortality in recanalized patients

8. •Distal MCA – 44%
•Proximal MCA - 30%
•Terminal ICA - 6%
•Tandem cervical ICA/MCA
-27%
•Basilar artery- 30%

10. Case selection- mechanical
thrombectomy
• IV-tPA given in MVO- but not effective-
(bridging)
• IV-tPA not possible-( >4.5 hrs, wake-up
strokes, anti-coagulants, recent surgery etc. )
(and MVO)

12. Issues
• 21 sites- 8-years- 127 patients
• Revascularization in 67%, seventeen
procedural complications
• Mostly used MERCI device- first generation;
• Trial completed over 8-years !!!
Time to groin puncture was 6 hrs 21 min !!!
Imaging to puncture- 2hrs 4min !!!

14. Intra-arterial methods
• IA-tPA- 71% (51)
• Microsonic – 71% SV Infusion with
tPA (14)
• Merci- 73% (77)
• Penumbra- 85% (39)
• Solitaire- 75% (4)- used in 1.6%
Rapidity of treatment
• IMS 1 and II trials, 30-minute delay
– 10% less probability of independent
existence
• Delay in IMS III was 32 min longer
than IMS I study
Case selection?
Imaging for MVO, older devices; delay

15. Subset analysis
IMS III– CTA group
– with ICA and
MCA - positive

16. IMS -III

17. 31.5 36.6
46.9
0
20
40
60
MS PS RS
MRS<=2
MS
PS
RS
MERCI
PENUMBRA
SOLITAIRE
AJNR, Jan, 2013

18. Randomised trials – General criterion
• Randomised (Intervention Vs Standard
medical therapy)
• Documented site of occlusion.
• Time based: 6 hrs (initiation of IA therapy)
• Small Core
• Predominantly stent retrievers.

19. MR CLEAN
(Netherlands)
ESCAPE
(CANADIAN)
EXTEND IA
(AUSTRALIAN)
SWIFT PRIME
(USA)
REVASCAT
(SPANISH)

20. Comparison of protocol- Randomised (Intervention
Vs Standard medical therapy)
• Documented MVO.- ICA, MCA (M1, M2)
• Time based: 6 hrs (initiation of IA therapy)-
(8 hrs – REVASCAT; 12 hrs – ESCAPE)
• Small Core - CT ASPECTS ≥ 6
• CTP – EXTEND IA; SWIFT PRIME
• Predominantly stent retrievers.
• 86.1 to 100% (100 % in EXTEND IA & SWIFT PRIME)
• (NIHSS scores were 17 (interquartile range, 13–21)

21. TICI 2B/3 – 59% - 88% - (previous trials 25%, 41%)
Recanalization – TICI 2B/3

22. Absolute Benefit (good outcome) : 13.5% to 31.4%
(Statistically significant)
mRS (90 d)

23. no significant difference
sICH

24. Device complication

25. Absolute mortality benefit : 8.6%
(Statistically significant in ESCAPE)
Mortality

26. Comparison of NNT:
EVT: NNT (benefit) - 3.1 to 4.2 (excluding MR CLEAN)
IV tPA ( 3 – 4.5 hours) – 13.8 (ECASS – 3)
Primary PCI (prevent re-infarction) – 33

27. IV tPA – Does it make a difference?
Subgroup analysis (ESCAPE) -
Received intravenous r-tPA – 235; (OR, 2.5 [1.6–4.0])
No intravenous r-tPA – 76; (OR, 2.6 [1.1– 5.9])
Conclusion:
Stent retriever based mechanical thrombectomy to be
offered if there are contraindications to IV tPA

28. Advanced Imaging:
CTA used to detect MVO
CT Perfusion:
 SWIFT Prime – Criterion changed (71 with perfusion; 125 without)
 possibility that patients who may have responded to therapy
were excluded.
Site of occlusion should be documented:
 studies not designed to validate the utility of the advanced
imaging selection criteria

29. Techniques:
 Stent retriever
 Stent retriever + Proximal balloon guiding
catheter (flow arrest)
 Stent Retriever +
Lesional aspiration
(Distal access catheters)Humphries W, Hoit D, Doss VT, et al. Distal aspiration with retrievable stent assisted thrombectomy for the treatment of acute
ischemic stroke. J Neurointerv Surg. 2015;7:90-94.
Nguyen TN, Malisch T, Castonguay AC, et al. Balloon guide catheter improves revascularization and clinical outcomes with the
Solitaire device: analysis of the North American Solitaire Acute Stroke Registry. Stroke. 2014;45:141-145.

30. AHA/ ASA guideline 2015:
Patients should receive endovascular therapy with a stent
retriever if they meet all the following criteria (Class I; Level of
Evidence A). (New recommendation):
 prestroke mRS score 0 to 1
 acute ischemic stroke receiving intravenous r-tPA within 4.5
hours of onset
 causative occlusion of the internal carotid artery or proximal
MCA (M1)
 age ≥18 years
 NIHSS score of ≥6
 ASPECTS of ≥ 6
 treatment can be initiated (groin puncture) within 6 hours of
symptom onset

31. AHA/ ASA guideline:
 Carefully selected patients with anterior circulation
occlusion who have contraindications to intravenous r-
tPA, endovascular therapy with stent retrievers
completed within 6 hours of stroke onset is reasonable
(Class IIa; Level of Evidence C).
 Carefully selected patients with acute ischemic stroke in
whom treatment can be initiated (groin puncture) within 6
hours of symptom onset and who have causative
occlusion of the M2 or M3 portion of the MCAs, anterior
cerebral arteries, vertebral arteries, basilar artery, or
posterior cerebral arteries (Class IIb; Level of Evidence
C)

32. AHA/ ASA guideline:
 Stent retrieval may be reasonable for patients
with acute ischinitiated (groin puncture) within 6
hours emic stroke in whom treatment can be of
symptom onset and who have prestroke mRS
score of >1, ASPECTS >1, ASPECTS <6, or
NIHSS score <6 and causative occlusion of the
internal carotid artery or proximal MCA (M1)
 Observing patients after intravenous r-tPA to
assess for clinical response before pursuing
endovascular therapy is not required to achieve
beneficial outcomes and is not recommended.
(Class III; Level of Evidence B-R).

33. Comparison of IAT processes.
Brijesh P. Mehta et al. J Am Heart Assoc 2014;3:e000963
© 2014 Brijesh P. Mehta et al.
Time is the key ….post Quality improvement (QI) –
Parallel processing
Pre and post Quality improvement (QI) – Parallel processing

34. •68/M, DM, HTN, CAD, underwent PTCA to LAD
•Admitted for surgery of aortic stenosis.
•Double anti-platelets was stopped
•Patient developed acute onset right side weakness
with aphasia.
IV- tPA given, no improvement

36. • Left hemiplegia, left UL and LL 0/5
• 5:14AM

37. 6:22AM

38. 8:07 AM
Patient made gradual recovery
Left LL 4/5 and UL 3/5 - 30 day follow up
mRS at 90 days- 0

39. • 60 years old female.Acute onset left hemiparesis and left
facial weakness; CT Brain , CTP and CTA done 6 1/2 hours after
ictus.

40. Issues …
Beyond 6 hours – Should you consider MT?
ESCAPE: up to 12-hours – positive trial
6 hours
49 patients
rate ratio, 1.7; (95% CI, 0.7 to 4.0)
Not significant; however few numbers.
REVASCAT: upto 12 hours, positive trial
Data not provided.

41. • Category: < 6H Vs > 6 h (or) unknown time [UOS] (or) wake up [WUS].
• T < 6H – 654
• T > 6H - 205 (128 T > 6H, 55 WUS and 22 UOS).
Non significant difference in clinical
outcome, recanalization rates and SICH

42. Tissue at risk/ core > 3
Later time windows/
wake up

43. • 63 /M, AVR, Coumadin
• INR of 2.5
• RT hemiparesis - 2/5 in leg
and 0/5 in arm
• Global aphasia
CBF CBV
Solitaire
stent was
deployed
Issues….. Intracranial atherosclerosis

44. Mechanical thrombolysis –
TOC for MVOhours
• Recent trials are watershed in stroke
management
• Mechanical recanalization is standard part of
stroke treatment
• Issues – beyond 6 (7.3), tandem lesions,
technique evolution, advacned imaging role…
• Challenge and responsibility !
• Focus on building stroke intervention centers and
network of peripheral and referral stroke centers

47. • 60 years old female.
• h/o hypertension and hypothyroidism
• Acute onset left hemiparesis and left facial weakness
• No history of LOC/seizures
• CT Brain , perfusion and angio done 6 1/2 hours after ictus.

50. 2 months later

51. • 41 year old male, Severe MR, EF 20%
• Stroke in sleep, NIHSS 14 on admission

52. 6:22AM

53. Patient made gradual recovery
Left LL 4/5 and UL 3/5 - 30 day follow up
mRS at 90 days- 0

54. • Retrospective; September 2010 and April 2013
• Compared proximal vs distal approach
• Weight-adapted bolus of tirofiban followed by a continuous infusion
for 24 h to prevent in-stent thrombosis
• After exclusion of cerebral hemorrhage on follow-up imaging, 500 mg
of acetylsalicylacid (ASA) and 300 mg of clopidogrel

57. ISC 2013

58. Clinical …• Left hemiplegia, left UL and LL 0/5
• 5:14AM

59. 6:22AM

60. 8:07 AM
Patient made gradual recovery
Left LL 4/5 and UL 3/5 - 30 day follow up
mRS at 90 days- 0

61. • 63 /M, AVR, Coumadin
• INR of 2.5
• RT hemiparesis - 2/5 in leg
and 0/5 in arm
• Global aphasia
CBF CBV
Solitaire stent was deployed

62. • 60 years old female.Acute onset left hemiparesis and left
facial weakness; CT Brain , CTP and CTA done 6 1/2 hours after
ictus.

63. For more information on:
STROKE & NEUROVASCULAR INTERVENTIONS:
URL:
www.sanif.co.in
Facebook:
https://www.facebook.com/strokeawarenessindia
https://www.facebook.com/vipul.gupta.35175
Twitter
https://twitter.com/drvipulgupta25
LinkedIN
https://in.linkedin.com/pub/dr-vipul-gupta/51/8a1/25a
YouTube
Channel: Stroke & Neurovascular Interventions
www.youtube.com/c/StrokeNeurovascularInterventionsfoundation
Dr Vipul Gupta

64. Thank you ….