University of Michigan Stroke Team
Considerations regarding endovascular stroke treatment
Large artery occlusion has been associated with worse functional outcome in acute stroke
patients.1 Endovascular acute stroke treatment can recanalize occluded arteries. Early studies of
endovascular treatment did not show benefit but they were limited as they enrolled patients
without large artery occlusions, used techniques that are not as effective as current technology,
and treated patients long after symptom onset.2 Recent trials using contemporary devices and
treating patients early after symptom onset have shown improvement in functional outcome and
reductions in mortality.3-5 Imaging criteria (beyond large vessel occlusion,) were used to select
patients in some of the trials, but it is unclear if advanced imaging of collaterals or perfusion is
necessary to select patients for treatment.
While there is emerging consensus that endovascular treatment is an effective treatment there is
still some uncertainty regarding patient selection. Many of the trials had selection bias that limits
the generalizability of their results. As such, the criteria below are a starting point when
considering patients for endovascular treatment. Therapy should be individualized for each
patient at the discretion of the stroke and neuro-interventional physicians on-call.
When considering endovascular stroke treatment, the following general thoughts should be kept
in mind:
 Patients eligible for IV tPA should receive IV tPA as quickly as possible, regardless of
their eligibility for endovascular treatment.6 The majority of subjects in the recent
endovascular treatment trials also received IV tPA.
 Endovascular treatment is recommended for selected patients who have a large vessel
occlusion, regardless of whether they are eligible for or have received IV tPA.
 If there is suspicion of a large vessel occlusion based on the clinical syndrome, vessel
imaging should be obtained to confirm the occlusion and guide endovascular treatment.
o In general, CTA of the head and neck is the vessel imaging modality of choice as
it can be done quickly.
o IV tPA should not be delayed for CTA, or other imaging, when the patient is
otherwise eligible for IV tPA. (E.g. CTA of the head and neck can be done during
IV tPA administration.)
o Data are limited regarding what NIHSS score predicts large vessel occlusion,7-10
but in general, patients with an NIHSS score >9 due to new deficits, at any time
during evaluation (i.e. present with an NIHSS of 16 and improve to 4), are likely
to have a large vessel occlusion.
o Some patients with large artery occlusion will have low NIHSS scores. These
patients may still benefit from endovascular treatment; although, potential risks
Approved 25-March-2015 by UM Stroke Team
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and benefits must be weighed. The NIHSS scores in the endovascular treatment
trials were generally high (see table below).
o A hyperdense vessel sign in the appropriate clinical setting suggests large artery
occlusion.
 CTA may still be considered in the setting of a hyperdense vessel as it
provides information about the cervical vessel and arch anatomy that may
be useful for procedural planning.
o It may be appropriate, in certain cases, to go directly to angiography without CTA
based on availability of angiography, level of suspicion for an appropriate large
artery target, or other patient factors.
Since time to recanalization is an important predictor of outcome, every effort should be
made to proceed with endovascular treatment as soon as possible in eligible patients.
Target time for groin puncture is within 6 hours of symptom onset, and ideally sooner. It
may be reasonable to exclude a patient from endovascular treatment when recanalization
before 6 hours is thought to be highly unlikely.
o Patients who are transferred to UM should aim to arrive by 4.5 to 5 hours after
symptom onset to meet this time goal.
o These time windows may be slightly extended for patients with favorable
radiographic profiles (e.g. ASPECTS,11 collateral flow, small infarct core, etc.) or
other clinical factors. This is an individualized decision that should be made
collaboratively with the stroke and neuro-interventional physicians on-call.
The role of perfusion imaging in patient selection is unclear. It is not required prior to
endovascular treatment.
Patients with posterior circulation strokes have not been well evaluated in clinical trials
of endovascular treatment. Time windows for treatment of posterior circulation strokes
may be longer than for anterior circulation strokes. Consideration can be given to
treatment up to, and beyond, 24 hours from last normal time, but this is an individualized
decision that should be made collaboratively with the stroke and neuro-interventional
physicians on call.
Intubation and general anesthesia should only be used when necessary during
endovascular stroke treatment. Endovascular stroke treatment is not an independent
indication for intubation and general anesthesia and there is some evidence to suggest
that there may be an association between the use of general anesthesia and poor outcome
after endovascular stroke treatment.12
As there may be an association with longer procedural times and worse outcomes, if the
endovascular procedure is ongoing for more than 90 minutes, consider a pause to discuss
the risks and benefits of continuing.
Approved 25-March-2015 by UM Stroke Team
Table: Information from recent trials
Study
Protocol
time
Actual time
(median)
MR
CLEAN3
Initiated
within 6
hours
Onset to
groin
puncture 4.3
hours
(75%tile 5.2
hours)
ESCAPE4
Randomizat
ion within
12 hours
Onset to
groin
puncture 3h
(75%tile
5.3h)
EXTENDIA5
Groin
puncture
within 6
hours, end
by 8 hours
Onset to
reperfusion
4h (75%tile
6h)
Onset to
groin
puncture 3.5h
(75%tile
4.2h)
Onset to
reperfusion 4
hours
(75%tile 4.6
hours)
Other
imaging
selection
methods
Target
lesion
IV
tPA
ICA, M1,
M2, A1, A2
(though only
1 ACA
stroke patient
enrolled)
89%
Median
(IQR)
NIHSS in
treatment
group
17 (14, 21)
Small
infarct
core,
moderategood
collaterals,
APSECTS
6-10
ICA, M1,
M2s (two or
more)
76%
16 (13, 20)
CTP
mismatch
ratio >1.2;
mismatch
volume
>10mL;
infarct core
<70mL
ICA, M1, M2
100%
17 (13, 20)
Some
exclusions
PLT < 40;
INR > 3.0;
BP
>185/110;
infarction
in the same
distribution
within 6
weeks
NIHSS < 6
tPA
exclusions
References
1. Lima FO, Furie KL, Silva GS, et al. Prognosis of untreated strokes due to anterior circulation proximal intracranial arterial occlusions
detected by use of computed tomography angiography. JAMA Neurology. 2014;71:151-157.
Hacke W. Interventional thrombectomy for major stroke — a step in the right direction. NEJM. 2015;372:76-77.
Berkhemer OA, Fransen PSS, Beumer D, van den Berg LA, Lingsma HF, Yoo AJ, et al. A randomized trial of intraarterial treatment for
acute ischemic stroke. NEJM. 2015;372:11-20.
4. Goyal M, Demchuk AM, Menon BK, Eesa M, Rempel JL, Thornton J, et al. Randomized assessment of rapid endovascular treatment of
ischemic stroke. NEJM. 2015;372:1019-1030.
5. Campbell BCV, Mitchell PJ, Kleinig TJ, Dewey HM, Churilov L, Yassi N, et al. Endovascular therapy for ischemic stroke with perfusionimaging selection. NEJM. 2015;372:1009-1018.
6. Jauch EC, Saver JL, Adams HP, Bruno A, Connors JJ, Demaerschalk BM, et al. Guidelines for the early management of patients with acute
ischemic stroke. Stroke. 2013;44:870-947.
7. Cooray C, Fekete K, Mikulik R, Lees KR, Wahlgren N, Ahmed N. Threshold for NIH stroke scale in predicting vessel occlusion and
functional outcome after stroke thrombolysis. International Journal of Stroke. In press; 2015.
8. Fischer U, Arnold M, Nedeltchev K, Brekenfeld C, Ballinari P, Remonda L, et al. NIHSS score and arteriographic findings in acute
ischemic stroke. Stroke. 2005;36:2121-2125.
9. Heldner MR, Zubler C, Mattle HP, Schroth G, Weck A, Mono M-L, et al. National institutes of health stroke scale score and vessel
occlusion in 2152 patients with acute ischemic stroke. Stroke. 2013;44:1153-1157.
10. Olavarria VV, Delgado I, Hoppe A, Brunser A, Carcamo D, Diaz-Tapia V, et al. Validity of the nihss in predicting arterial occlusion in
cerebral infarction is time-dependent. Neurology. 2011;76:62-68.
11. http://www.aspectsinstroke.com/. Accessed March 19, 2015.
12. Brinjikji W, Murad MH, Rabinstein AA, Cloft HJ, Lanzino G, Kallmes DF. Conscious sedation versus general anesthesia during
endovascular acute ischemic stroke treatment. AJNR. 2015;36:525-529.
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