Results of the thrombectomy in treatment at acute ischemic stroke patient at Bach Mai hospital

JOURNAL OF MEDICAL RESEARCH

RESULTS OF THE THROMBECTOMY IN TREATMENT AT
ACUTE ISCHEMIC STROKE PATIENT AT BACH MAI HOSPITAL
Quang Anh Nguyen1,2, Luu Vu Dang1,2, Thong Pham Minh1,2,
Tuan Tran Anh1, Kien Le Hoang¹, Thien Nguyen Tat¹,
Trang Nguyen Thi Thu¹, An Nguyen Huu¹, Hanh Nguyen Thi Thuy³
¹Radiology Center, Bach Mai Hospital
²Radiology Falculty, Hanoi Medical University
³Medical Record Storage, General Planning Department, Bach Mai Hospital
Evaluating the results of thrombectomy in acute ischemic patients (AIS) due to large vessel occlusion
(LVO) in Bach Mai hospital. Patients suffering from AIS due to LVO received endovascular thrombectomy
during 05/2012 to 05/2018 at the Radiology Center of Bach Mai University Hospital. They were divided into
2 groups of treatment: group 1 was treated by rt-PA + devices while group 2 received thrombectomy alone.
The treatement results and characteristics were analyzed and compared. Mean age was 59.9 ± 14.5, 54%
male. The NIHSS and ASPECTS basline were 15.8 and 6.2 with the distribution of occlusion sites being 55%
ICA, 40% MCA, and 5% BA. Good revascularization (TICI 2b-3) and good clinical recovery (mRS ≤ 2) after
3 months achieved in 71.6% and 48.3% of all patients. Intracranial symptomatic hemorrhage was seen in
7.2% of patients. There was no difference in good revascularation (69.3% vs 73.3%) and favourable outcome
after 3 months (45.3% vs 50.5%) between the two groups of treatment (p > 0.05). Thrombectomy for AIS
patients due to LVO was very effective with high rate of good revascularization and clinical recovery. Using
r-tPA prior to endovascular treatment may delay time without higher rate of revascularation and outcome.
Keywords: Acute ischemic stroke (AIS), Large vessel occlusion (LVO), Thrombectomy.

I. INTRODUCTION
Acute ischemic stroke (AIS) is the second
leading cause of mortality and third leading
cause of disability worldwide, especially due
to the large vessel occlusion (LVO) including
basilar (BA), internal carotid (ICA) and middle
cerebra artery (MCA) [1; 2]. Intravenous

recombinant tissue-type plasminogen activator
(rt-PA) was approved in 2005 and still was the

first indication for AIS patient came within 4.5
hour, but the rate of recanalization in those
suffering from LVO was very low (15%) [1; 2].
In 2015, five randomized controlled trials of
endovascular treatment (EVT) for AIS were
published pointing out the positive result of
thrombectomy due to LVO [3 - 7]. In Vietnam,
doctors have started to use the stent retriever
beginning in 2012 with the first case in Bach
Mai Hospital (BMHU). Currently, the number

Corresponding author: Nguyen Quang Anh,

of AIS cases due to LVO treated by EVT have
increased quickly every year. In this study,
we have summarized the results and effect of
thrombectomy with experience from 05/2012
to 05/2018.

Radiology Center, Bach Mai Hospital
Email:
Received: 27/11/2018
Accepted: 12/03/2019

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II. METHODS

2.Methods

1. Selection criteria

Design: crosssectional retrospective study,
single-center.

292 patients, who suffered from AIS during
the period between May 2012 and May 2018,
and treated by thrombectomy at BMUH, were
analyzed. For further evaluation, we divided all
stroke patients into 2 groups of treatment: (1)
treated by rt-PA + devices while (2) received
thrombectomy alone. They were compared
in detail, including clinical characteristics,
neuroimaging findings, and functional outcome.
* Inclusion criteria:
The acute stroke protocol has been employed
at BMUH since May 2012 and was updated
annually according to the recommendation
of ASA (American Stroke Association)/ AHA
(American Heart Association) guideline and
newest randomized controlled trials (RCTs) in
the world [8]:

• Age ≥18
• Diagnosis of AIS due to LVO, confirmed in
image of MSCT/MRI
• NIHSS ≤ 25
• ASPECTS ≥ 6 and pc-ASPECTS ≥ 7
• Time window of treatment (from onset
symptoms): up to 6th hours for anterior & 12th
hours for posterior circulation
• The patient and/or their realtives signed in
consent form for agreement
* Exclusion criteria:
• Hemorrhage or no LVO identified in MRI
or MSCT
• Large ischemic core in non-contrast
computed tomography (NCCT) with ASPECTS
≤5 or pc-ASPECTS ≤ 6
• Unknown onset time or over time window
of treatment (> 6 hours with anterior and > 12
hours with posterior circulation)
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Data collection: using patients’ charts.
Descriptive data were expressed as number
of patients, percentage, NIHSS, ASPECTS
with standard deviation. In the univariate
analysis, distributions in age, sex, NIHSS,
and other parameters between different
outcome groups were assessed using a chisquare or independent t-test depending on
the characteristics of data. Statistical analyses
were performed using SPSS software version

23. A p value <0.05 was regarded as significant.
Odds ratio and the 95% confidence intervals
were measured.
3. Protocol of research
In admission, emergency doctors checked
and evaluated the neurological deterioration
based on National Institutes of Health Stroke
Scale (NIHSS) scores at baseline. The clinical
information and medical history were also
collected. The imaging assessement including
cerebral non-contrast computed tomography
(NCCT) and CT Angiography (CTA) were
performed immediately in Multislide Computed
Tomography (MSCT) to identify ischemic core
region and obtain location of vessel occluded.
The CT Perfusion also used in some special
cases for clearly identify volume of brain tissue
at risk of infarction (ischemic penumbra), and
volume of brain irreversibly infarcted (ischemic
core) [9]. Patients who came in time window <
4.5 hours from onset with no contraindication
to actylyse will received IV rt-PA immediately
before going to the DSA room for endovascular
treatment. They were enrolled to group 1 while
group 2, in the other hand, included all other
patients who came after 4.5 hours from onset
or having any contraindication to rt-PA. They
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consequently underwent thrombectomy alone
without IV rt-PA
The following parameters related to the
procedure were recorded: time of stroke onset,
time to emergency department (ED), IV rtPA bolus, groin puncture, and recanalization.
Successful revascularization at the end of the
thrombectomy procedure was defined as a
score of 2b or 3 on the Thrombolysis in Cerebral
Infarction (TICI) scoring system (grade 0: no
perfusion; grade 1: minimal recanalization;
grade 2a: partial antegrade reperfusion of <50%
previously occluded target artery ischemic
territory; grade 2b: antegrade reperfusion
of 50 - 99% previously occluded target
artery ischemic territory; grade 3: complete
perfusion) [10]. CT or MRI imaging after 16th24th hour of thrombectomy was indicated by
clinical doctors. It was performed at radiology
center and interpreted by neuroradiologists. In
this step, the sICH was also evaluated based
on Heldenberg bleeding classification [11]. 3
months follow-up mRS was done by clinical
doctors based on patients’ symptoms.
4. Ethics
All procedures were performed in this
study involving human participants were in
accordance with the ethical standards of the
institutional and/ or national research committee
and with the 1964 Helsinki declaration and
its later amendments or comparable ethical

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standards. The ethical clerance of trial also
approved by BMUH ethical committee and did
not interfere the treatment decision for patient.
The research was approved by the Ethics
Committee of Hanoi Medical University, No
206/HĐĐĐĐHYHN on December, 30th 2016

III. RESULTS
There were 292 cases of AIS treated by
thrombectomy at our hospital during period from
May 2012 to May 2018. Mean age was 59.9 ±
14.5, range of 19-88 with male/female ratio of
1.2. Patients’ history regarding to some chronic
diseases with top 3 came from hypertension
(72.2%), diabetes mellitus (41.7%) and atrial
fibrillation (14.4%). Average time from onset to
hospital was 107.3 ± 76.1 min, from hospital
admission to femoral puncture was 77.3 ± 37.1
min, and from onset to end of procedure was
254.1 ± 95.3 min.
The median NIHSS and ASPECTS score at
baseline was 15.8 and 6.2, respectively.
Regarding to the site of occlusion, 92.5%
located at the anterior circulation while only
7.5% at the posterior one. We also had 21
patients who suffered from tandem occlusion
(both ICA and M1 occlusion), of which 12

cases treated by ICA wall stent in combination
with MCA thrombectomy, and 9 cases treated
by thrombectomy alone.

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Table 1. Baseline characteristics of acute ischemic patients and comparision
between two groups of treatment
Characteristic

Total
(n = 292)

Group 1
(n = 127)

Group 2
(n = 165)

59.9
19 - 88

57.4
19 - 88

60.6
25 - 86

Gender – male sex (%)

54

53

57

History (%)
Hypertension
Diabetes mellitus
Atrial fibrilation

72.2
41.7
14.4

65.3
45.3
10.7

77.1
39
17.1

NIHSS (median)
Min-Max

15.8
8-22

14.6
8-20

16.3
10-22

ASPECTS (median)
Min-Max

6.2
6-10

6.8
6-10

6.1
6-9

Occlusion site
ICA
MCA
BA
Tandem

140 (48)
130 (44.5)
22 (7.5)
21

58 (45.7)
62 (48.8)
1 (0.7)
7

82 (49.7)
68 (41.2)
21 (12.7)
14

Time from admission to the puncture (min)

77.3 ± 37.1

90.8 ± 35.2

68.2 ± 43.4

Device used
Stent retriever
Aspiration
Solumbra

186 (63.7)
62 (21.2)
44 (15.1)

84 (66.1)
26 (20.5)
17 (13.4)

102 (61.8)
36 (21.8)
27 (16.4)

Age (median) (year)
Min-Max

Successful recanalization (TICI 2b-3) was achieved in 71.6% patients with rate of symptomatic
ICH at 24 - 48h imaging found in only 7.2% patients. After 3 months’ post procedure, 48.4% patients
had a favorable outcome, and mortality accounting for 15,3% of patients. Additionaly, the median
time from emergency department (ED) to groin puncture were 77 minutes with 90 minutues in group
1 and only 68 minutes in group 2 , p < 0.05 (figure 1).

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Figure 1. Endovascular thrombectomy results and comparision between two
groups of treatments
In the comparision, there was no difference
between the two groups in rates of good
recanalization (68.9% vs 75.1%, p = 0.24),
symptomatic ICH post procedure (7.9% vs
6.7%, p = 0.69), and good clinical outcomes
(45.9% vs 49.4%, p = 0.55).

IV. DISSCUSION
In our study, we enrolled a total of 292
cases using endovascular thrombectomy for
period of 6 years. Fifty-four percent of patients
were male, higher than SWIFT (42%) and IMS
III (50%) but lower to MR CLEAN (57.9%) [3;
6]. The average age was 59.9 ± 14.5, younger
than in MR CLEAN (65.4 ± 14) and ESCAPE
(71 ± 11.5) [3; 4]. In addition, most of patients
had the history of hypertension (72.2%), which
was similar to SWIFT (74%) [12]. Other history
with high frequently in our study were diabetes
mellitus (41.7%) and atrial fibrillation (14.4%).
The average time from onset symptoms to
hospital admission was 107.3 ± 76.1 min and
to end of procedure was 254.1 ± 95.3 min,
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which was similar to the result 260 ± 51.2 min
of MR CLEAN study [3].
In our study, the anterior circulation
occlusion accounts for 92.5%, same as results
of other RCTs, but the rate of ICA occusion
was especially higher than others (table 2), in
which M1 occlusion accounts the most in their
studies (TREVO 2: 60%, SWIFT: 61%) leading
to higher average baseline NIHSS and lower
average baseline ASPECTS: 15.8 and 6.2,
respectively [12, 13].
Up to now, there have been three classes of

mechanical thrombectomy devices that have
been approved by the FDA: coils retrievers
(Merci) in 2004, aspiration devices in 2008,
and stent retrievers (Solitaire…) 2012 [14-16].
Currently, most evidence including ASA/AHA
guidelines support the use of stent retrievers
over other types of mechanical devices in
endovascular treatment for patients with AIS
[8]. In our practice, we used the stent retriever
in 163 cases. Only 62 cases (21.2%) were
done by aspiration devices like ACE 60, 64,
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68…, and another 44 cases (15.1%) were the
combination of stent retriever and aspiration
(solumbra technique), less than this percentage
of FAST study [17]. In our experience, the
aspiration devices are preferred for use in the
ICA and basilar artery, in which the thrombus is
bigger than other vessels (M1, M2, P1…). In
cases where the vessel was tortuous, leading
to inaccessibility of the thrombus by aspiration
tube, stent-retriever or Solumbra technique
were better choices for rescue therapy.
Further study with more cases and experience
sharing will help to clarify the advantages
and disadvantages of these two mechanical
devices in clinical practice.

The results of our data were comparable to
some previously published major international
randomized endovascular trials (details in table
2 ). In terms rates for successful recanalization,
our results are equally to ESCAPE 72.4%, and
a little bit lower to SWIFT (83, 3%) [4; 12].
Regarding the functional outcome, our results
of favorable outcome after 3 months (48.4%)
was higher compared to MR CLEAN (32,6%)
but lower than ESCAPE (53%) [3; 4] . In the
aspect of sICH rate, ours results was 7.2%,
similarly to MR CLEAN (7.7%) and TREVO
2 (7%) but higher when compared to SWIFT
(2%) and ESCAPE (2.6%) [3; 4; 12; 13].

Table 2. Comparision between ours and others studies
Study

N

ICA
occlusion
(%)

Good
recanalization (%)

mRS 0-2
(%)

Mortality
(%)

sICH (%)

Ours

180

55

72

48.4

15.3

7.2

SWIFT

58

22

83.3

58.2

17.2

2

MR CLEAN

233

25.3

59

32.6

18.9

7.7

ESCAPE

165

27.6

72.4

53

10.4

3.6

Notably, the inclusion criteria of these RCTs
basically excluded patients with posterior
circulation stroke. The THRACE trial, as an
example, included the superior third of the
basilar artery as a candidate for EVT but in the
end, only 2 patients having basilar occlusion
were enrolled, and accounted for only 1% of
included patients [14]. In our study, only 15
cases (8.3%) of basilar occlusion were treated
by EVT with rate of good recanalization was
53.3% but favorable out come only was 26.7%.
The posterior circulation site was one of the
not good predictors for the outcome of AIS
patients, but we need more trials to confirm.
Regarding to the role of IV rt-PA in
combination with thrombectomy in treatment
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of AIS, we have divided our patients into two
groups. 127 patients in group 1 and 165 patients
in group 2 with the same characteristic of age,
gender (M/F) and NIHSS/ ASPECTS baseline.
However, the comparision showed that with IV
rt-PA prior to thrombectomy treatment, the time
from adimission to groin puncture in group 1
was delayed compared to group 2, 90 vs 68
minutes, respectively, p < 0.001. In addition,
these two groups shared a similar rate of good

recanalization (69 vs 75%), sICH (7.9 vs 6.7%)
and favorable outcome after 3 months (45.9 vs
49.4%) with no significantly difference p > 0.05.
This will lead to another question of whether
we should use IV rt-PA in treatment of LVO or
not.
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V. CONCLUSION
This study demonstrated a promising
outcome with high rate of good revascularization
and clinical recovery for endovascular
thrombectomy in acute ischemic stroke

patients due to large vessel occlusion. Using
rt-PA prior to the endovascular treatment may
lead to delay time without higher rate of good
revascularation and outcome.

Figure 2. Case illustration – Do Van K., 75 yo, 2nd hour from onset symptom.
Non contrast CT Scanner (a) showed the
ischemic lesion in the right temporal lobe with
proximal M1 occlusion, revealed clearly both in
CTA (b) and DSA (c). Stent-retriever used in
this case (d) to archinve TICI 3 recanalization
(e). MRI follow up after 24 hours showed no
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extension of core lesion in DWI (f), good
revascularization of right M1 in TOF-3D (g)
without hemorrhagic complication.

INFORMED CONSENT
Informed consent was obtained from all
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patients and their relatives included in the study
with understanding and allow our research
group to use their studying image, data, and
information in writing/publishing scientific
article

FUNDING
This research received no external funding.

CONFLICTS OF INTEREST
The authors declare no conflict of interest.

ACKNOWLEDGEMENTS
We would like to thank Director Board of
Bach Mai Hospital & Hanoi Medical University
that allowed us to do this research. We also
want to thank all the Reviewers and Editors of
Medical Research Journal that helped us in all
proccess of publishing this article.

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