PROximal TEmporary oCclusion Using Balloon Guide Catheter for Mechanical Thrombectomy(PROTECT-MT)
Phase: NA
Conditions: Acute Ischemic Stroke, Large Vessel Occlusion, Thrombectomy, Thrombosis
Sponsor: Changhai Hospital

 
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PROximal TEmporary oCclusion using balloon guide 
caTheter for Mechanical Thrombectomy (PROTECT-MT) 
 
 
Sponsor: The First Affiliated Hospital of Naval Medical University 
(Changhai hospital) 
Project Leader: Professor Jianmin Liu 
Contract Research Organization: CCRC Medtech (Shanghai) Co., Ltd. 
Protocol No.: PROTECT-MT 
Protocol Version: V4.0 
Protocol Date: Oct 25, 2023 
 

 
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Table of Contents 
Table of Contents ............................................................................................................................................. 2 
Protocol Signature Page .................................................................................................................................. 4 
List of Abbreviations ........................................................................................................................................ 6 
Protocol Synopsis ............................................................................................................................................. 7 
1 
Study Background .................................................................................................................................. 11 
2 
Study Objective ...................................................................................................................................... 12 
3 
Study Design ........................................................................................................................................... 12 
4 
Study Population .................................................................................................................................... 13 
4.1 
Inclusion Criteria ......................................................................................................................... 13 
4.2 
Exclusion Criteria ........................................................................................................................ 14 
4.3 
Subject Withdrawal Criteria ......................................................................................................... 14 
4.4 
Premature Termination of the Study ............................................................................................ 15 
5 
Randomization and Treatment allocation ........................................................................................... 15 
6 
Study Method ......................................................................................................................................... 15 
6.1 
Study Outcomes ........................................................................................................................... 15 
6.1.1 
Primary Outcomes ....................................................................................................... 15 
6.1.2 
Secondary Outcomes ................................................................................................... 16 
6.1.3 
Safety Outcomes .......................................................................................................... 17 
6.1.4 
Cost Outcomes ............................................................................................................. 17 
6.1.5 
Blinding ....................................................................................................................... 17 
6.2 
Study Procedures ......................................................................................................................... 17 
6.2.1 
Schedule of Study Activities ........................................................................................ 17 
6.2.2 
Study Visits .................................................................................................................. 19 
7 
Statistical Analysis ................................................................................................................................. 23 
7.1 
Sample Size ................................................................................................................................. 23 
7.2 
Methods for Statistical Analysis .................................................................................................. 23 
8 
Study Monitoring ................................................................................................................................... 24 
9 
Data Management .................................................................................................................................. 24 
9.1 
Data Collection ............................................................................................................................ 24 
9.2 
Data Entry and amendment .......................................................................................................... 25 
9.3 
Lock of Database ......................................................................................................................... 25 
9.4 
Transfer of Database .................................................................................................................... 25 
10 Adverse Events/Serious Adverse Events .............................................................................................. 25 
10.1 Adverse Events (AEs) .................................................................................................................. 25 
10.1.1 Definition of Adverse Events ....................................................................................... 25 
10.1.2 Classification of Adverse Events ................................................................................. 25 
10.1.3 Recording and Follow up of Adverse Events ............................................................... 27 
10.2 Serious Adverse Event (SAE) ...................................................................................................... 27 
10.2.1 Definition of Serious Adverse Events .......................................................................... 27 
10.2.2 Reporting of Serious Adverse Events .......................................................................... 28 
11 
Ethical Considerations .......................................................................................................................... 28 
11.1 Ethical Requirements in Relevant Regulations ............................................................................ 28 
11.2 Informed Consent ........................................................................................................................ 29 

 
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11.3 Approval of the Study Protocol ................................................................................................... 29 
12 Quality Control of the Study ................................................................................................................. 29 
12.1 Investigators Training .................................................................................................................. 29 
12.2 Measures to Improve Subjects Compliance ................................................................................. 29 
12.3 Clinical Monitoring ..................................................................................................................... 30 
12.4 Data Management ........................................................................................................................ 30 
12.5 Maintenance of Source Documents ............................................................................................. 30 
13 Study Administration ............................................................................................................................ 30 
13.1 Organizational Structure .............................................................................................................. 30 
13.1.1 Steering Committee ..................................................................................................... 31 
13.1.2 Central Coordinating Center (CCC) ............................................................................ 31 
13.1.3 Imaging Adjudication Committee (Core Laboratory) .................................................. 31 
13.1.4 Clinical Events Committee (CEC) ............................................................................... 31 
13.1.5 Data and Safety Monitoring Board (DSMB) ............................................................... 32 
13.1.6 Outcome Assessment Committee (OAC) .................................................................... 32 
13.2 List of Study Sites ........................................................................................................................ 32 
13.3 Confidentiality Principle .............................................................................................................. 32 
13.4 Agreement on the Publication of Study Results .......................................................................... 33 
14 Fund ........................................................................................................................................................ 33 
15 Appendix ................................................................................................................................................. 35 
16 References ............................................................................................................................................... 42 
 
 
 

 
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Protocol Signature Page 
 
Signature of Sponsor 
Study Title: PROximal TEmporary oCclusion using balloon guide caTheter for Mechanical 
Thrombectomy (PROTECT-MT) 
Protocol No.: PROTECT-MT 
Version No.: V4.0 
Version Date: Oct 25, 2023 
 
Name of Sponsor 
Signature of Project Leader 
Date 
The First hospital Affiliated to 
Naval Medical University 
 
 
 
 
I have carefully read the contents of this clinical study protocol and confirm that all relevant 
contents are included in it. I will conduct this clinical study in strict compliance with the 
Declaration of Helsinki, current laws and regulations in China, as well as this clinical study 
protocol. 
I will be responsible for providing this clinical study protocol and relevant information to team 
members involved in this study and fully discuss it with them to ensure that they completely 
understand the contents of this study protocol and the study procedures. 
I will be responsible for accurately recording all required data in the Case Report Form (CRF) 
and cooperate in completing the clinical study report. I agree to allow the monitors, auditors and 
regulatory authorities to monitor, audit and inspect this clinical study. 
 
Name of the Principal 
Investigator 
Signature 
Date 
Jianmin Liu 
 
 
 
 
 
 

 
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Signature of Site 
Study Title: PROximal TEmporary oCclusion using balloon guide caTheter for Mechanical 
Thrombectomy (PROTECT-MT) 
Protocol No.: PROTECT-MT 
Version No.: V4.0 
Version Date: Oct 25, 2023 
 
I have carefully read the contents of this clinical study protocol and confirm that all relevant 
contents are included in it. I will conduct this clinical study in strict compliance with the 
Declaration of Helsinki, current laws and regulations in China, as well as this clinical study 
protocol. 
I will be responsible for providing this clinical study protocol and relevant information to team 
members involved in this study and fully discuss it with them to ensure that they completely 
understand the contents of this study protocol and the study procedures. 
I will be responsible for accurately recording all required data in the Case Report Form (CRF) 
and cooperate in completing the clinical study report. I agree to allow the monitors, auditors and 
regulatory authorities to monitor, audit and inspect this clinical study. 
 
Name of the Principal 
Investigator 
Signature 
Date 
 
 
 
 
 
 
 

 
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List of Abbreviations 
Abbreviation 
Definition 
AE 
Adverse Event 
AIS 
Acute Ischemic Stroke 
CRA 
Clinical Research Associate 
CRO 
Contract Research Organization 
CRF 
Case Report Form 
CT 
Computed Tomography 
CTA 
Computed Tomography Angiography 
DSA 
Digital Substraction Angiography 
EC 
Ethics Committee 
EDC 
Electric Data Capture 
eTICI 
Extended Thrombolysis in Cerebral Infarction 
GCS 
Glasgow Coma Scale 
ICF 
Informed Consent Form 
MRA 
Magnetic Resonance Angiography 
MRI 
Magnetic Resonance Imaging 
mRS 
Modified Rankin Scale 
NIHSS 
National Institute of Health Stroke Scale 
PI 
Principal Investigator 
SAE 
Serious Adverse Event 
 
 

 
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Protocol Synopsis 
Sponsor 
The First hospital Affiliated to Naval Medical University(Changhai hospital) 
Protocol No. 
PROTECT-MT 
Study Title 
PROximal TEmporary oCclusion using balloon guide caTheter for Mechanical 
Thrombectomy (PROTECT-MT) 
Study Design 
A prospective, multicenter, randomized controlled, open-label, blinded outcome 
evaluation (PROBE) trial 
Study Population 
Subjects with acute ischemic stroke(AIS) due to anterior circulation large vessel 
occlusion(LVO), and are eligible for mechanical thrombectomy(MT) according to 
local guidelines 
Study Objective 
To determine the effectiveness of balloon guide catheter(BGC) as compared to 
standard guide catheter on functional outcome (modified Rankin Scale [mRS] 
score) in patients with acute ischemic stroke due to anterior circulation large vessel 
occlusion. 
Number of planed 
Sites 
40-60 centers 
Inclusion/Exclusion 
Criteria 
Inclusion Criteria 
To be eligible for inclusion for this study, subjects are to satisfy all of the following 
criteria:  
1) 
Age ≥18 years. 
2) 
Diagnosis of AIS with confirmed anterior circulation LVO (including 
intracranial segment of the internal carotid artery, and the first or proximal 
second segment [M1 or proximal M2] of the middle cerebral artery) by brain 
imaging. 
3) 
To receive MT within 24 hours after AIS onset according to local guidelines. 
4) 
Preoperative mRS score of 0-1. 
5) 
Signed informed consent form obtained from the subject (or approved 
surrogate). 
Exclusion Criteria 
Subjects who meet any of the following criteria should be excluded from this study: 
1) 
Intracranial hemorrhage confirmed by imaging. 
2) 
Known or suspected pre-existing (chronic) large vessel occlusion in the 
symptomatic territory. 
3) 
Excessive vascular access tortuosity disables the use of balloon guide catheter. 
4) 
Intracranial stent implanted in the symptomatic territory that precludes the 
deployment/removal of the mechanical thrombectomy device. 
5) 
Any other condition that precludes the performing of mechanical 
thrombectomy procedure. 

 
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6) 
Occlusions in multiple vascular territories confirmed by Computed 
Tomography Angiography(CTA) or Magnetic Resonance Angiography(MRA). 
7) 
Subjects who are pregnant. 
8) 
Subjects who are allergy to the contrast agent. 
9) 
Subjects who refuse to cooperate or unable to tolerate interventional operation. 
10) Subjects whose expected lifetime are less than 90 days. 
11) Subjects who are unlikely to participate in follow-up assessments according to 
the investigator’s judgement.  
12) Any other condition that, according to the investigator’s judgement, not 
suitable for using of balloon guide catheter. 
Randomization, 
Group Assignment, 
and Blinding 
1. 
Randomization: 
After confirmation of eligibility, subjects will be randomized via an Internet-
based randomization system in a 1:1 manner to treatment with BGCs(Intervention 
group) or not(control group), stratified by site, preferred thrombectomy 
strategy(stent retriever VS aspiration VS stent retriever + aspiration), and onset to 
randomization time( <6 hours VS ≥6 hours) 
2. 
Group Assignment: 
Subjects will be treated with thrombectomy based on the results of randomization.  
Intervention group: Subjects treated with BGCs combined with conventional 
thrombectomy. 
Control group: Subjects treated with standard guide catheter combined with 
conventional thrombectomy. 
Any National Medical Products Administration (NMPA) devices (including the use 
of a thrombectomy stent, distal aspiration catheter, or combine use of both) are 
allowed. 
3. 
Blinding: 
Both patient and treating physician will be aware of the treatment assignment. But 
outcome evaluation would be blinded. Information on outcome at 90 days will be 
assessed through standardized forms and procedures, by a trained investigator 
blinded for treatment allocation. Interviews will be recorded. Assessors who are 
blinded to the treatment allocation will perform assessment of outcome on the 
modified Rankin scale on this information. Results of neuro-imaging will be also 
assessed in a blinded manner. Information on treatment allocation will be kept 
separate from the main study database. The steering committee will be kept unaware 
of the results of interim analyses of efficacy and safety. An independent DSMB 
statistician will combine data on treatment allocation with the clinical data in order 
to report to the data monitoring committee (DSMB). 
Study Outcomes 
1. Primary Outcomes 
Functional outcome, defined as modified Rankin Scale (mRS) score shift at 90 
days (±14 days) . 
2. Secondary Outcomes 

 
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1) 
Dichotomized mRS at 90 days after the operation (0-1 versus 2-6, 0-2 
versus 3-6, 0-3 versus 4-6, 0-4 versus 5-6, 0-5 versus 6). 
2) 
Change in stroke severity (NIHSS score) at 24 hours post treatment. 
3) 
Change in stroke severity (NIHSS score) at 7 days post treatment or 
discharge (whichever occurs first). 
4) 
Final infarction volume at 5-7 days post treatment . 
5) 
Technical success rate (defined as successfully navigating the guide 
catheter into the target vessel, and finishing the mechanical thrombectomy 
procedure without changing to another guide catheter). 
6) 
Reperfusion outcome (eTICI 2b or greater, eTICI 2c or greater, eTICI 3) in 
final angiogram. 
7) 
Reperfusion outcome (eTICI 2b or greater, eTICI 2c or greater, eTICI 3) 
after the first pass. 
8) 
Time from groin puncture to successful reperfusion (eTICI 2b or greater, 
eTICI 2c or greater). 
9) 
Percentage of subjects with acceptable revascularization quality (eTICI 2b 
or greater, eTICI 2c or greater) within 45 min of access. 
10) Number of thrombectomy attempts (final). 
11) Occurrence of emboli to a new territory. 
3. Safety Outcomes: 
1) 
Deaths at 90 days (±14 days) post treatment. 
2) 
Intracranial hemorrhage, symptomatic intracranial hemorrhage or 
asymptomatic intracranial hemorrhage at 7 days post treatment or discharge 
(whichever occurs first). 
3) 
Other serious adverse events (SAEs) adjudicated by the Clinical Events 
Committee. 
4) 
Any peri-procedural complications, including vessel dissection, arterial 
perforation, and femoral access complications, etc. 
4. Cost Outcomes: 
1) 
Health-related quality of life evaluated using EQ-5D. 
2) 
Utility-weighted mRS score. 
3) 
Duration of hospitalization. 
4) 
Treatment cost. 
Study Visits 
! 
Baseline  
! 
24 hours (±12 hours) post treatment 
! 
7 days (±2 days) post treatment or at discharge 
! 
90 days (±14 days) post treatment 
Statistical Analysis 
" 
Sample Size 
We based our estimations on the distribution of the mRS in the control group of the 
trial, which we derived from the intervention group of the MR CLEAN trial: mRS0: 

 
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3%; mRS 1: 9%; mRS 2: 21%; mRS 3: 18%; mRS 4: 22%; mRS 5: 6% and mRS 
6:21%. Based on previous studies, we assumed a favorable treatment effect with a 
common odds ratio (cOR) of 1.43, corresponding to an 8% absolute increase in the 
rate of mRS scores of 0-2. In a simulation with 5000 runs we computed the 
proportion of positive trials, for a given sample size. A sample size of 920 was 
determined to detect the superiority with a power of 87% and two-sided alpha of 
0.05. Considering 5% dropout rate and 5% crossover rate, a final sample size of 
1074, 537 per arm, would be needed. 
" 
Methods for Statistical Analysis 
Analyses will be performed using the intention-to-treat (ITT) principle.  
Statistical analysis will be detailed in a pre-specified Statistical Analysis Plan 
(SAP). 
Two interim analyses would be performed when 30% and 60% of the 90-day follow-
up data have been collected.  
 
 

 
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1 
Study Background 
Stroke has become the leading cause of death and adult disability in China [1]. According to 
Stroke Prevention and Treatment Report of China in 2019, there are 12.42 million stroke cases 
in people aged 40 years or above in China, 65% of whom are ischemic stroke. With population 
aging, stroke prevalence is continuously rising, bringing a heavy burden to the families and 
society [2]. 
The key to the treatment of acute ischemic stroke (AIS) is to recanalize the occluded vessels as 
early as possible and save the brain tissue around the core infarct area, namely the ischemic 
penumbra. With the publication of five randomized controlled trials comparing Endovascular 
treatment (EVT) with standard medical treatment in 2015 [3-7], EVT combined with intravenous 
thrombolysis has become the preferred treatment for patients with large vessel occlusion of 
anterior circulation within 6 hours of onset [8]. Subsequently, the DAWN and DEFUSE 3 studies 
in 2018 further extended the treatment time window to 24 hours [9, 10]. Although mechanical 
thrombectomy has significantly improved the successful recanalization rate in patients with 
acute ischemic stroke due to large vessel occlusion, a large proportion of patients still have poor 
clinical prognosis. How to improve the prognosis of these patients remain a clinical problem 
needed to be solved. 
The Balloon Guide Catheter(BGC) is device used during mechanical thrombectomy, which 
offers proximal flow control and a stable platform to facilitate the insertion and guidance of an 
intravascular catheter. Dilation of the balloon during the procedure would enable a significant 
flow arrest or reversal, and hence reduce the risk of thrombus fragmentation and distal embolism 
[11]. Some observational studies [12-17] have shown that the use of balloon guide catheter could 
improve the quality of final reperfusion, shorten the procedure time, and may lead to better 
clinical outcomes in patients undergoing thrombectomy. In a retrospective study involving 955 
patients, the final and first-pass reperfusion rates (mTICI 2b or 3) were 86.8% and 37.0% in 
BGC group, which were higher than those in the standard guide catheter group,i.e 74.7% and 
14.1% (P<0.001). Thrombectomy maneuvers (2.5±1.9 versus 3.3±2.1; P<0.001) and procedure 
time (54.3±27.4 min vs 67.6±38.2 min; P<0.001)were significantly decreased in BGC group 
compared with those in standard guide catheter group. In multivariate analysis, BGC usage was 
an independent factor for good clinical outcome (odds ratio: 1.40; 95% CI, 1.02 1.92; P = 0.038) 
[16]. In another prospective registry study, STRATIS (Systematic Evaluation of Patients Treated 
With Neurothrombectomy Devices for Acute Prevention Stroke), the first recertification (≥2c 

 
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and ≥2b) rates of three guide catheter(BGC, standard guide catheter, distal access catheter ) 
were (212/443 [48%] vs 16/62 [26%] vs 83/235 [35%]), and (294/443 [66%] vs 26/62 [42%] vs 
129/234 [55%]), respectively. The first recanalization rate of BGC group was higher than that of 
distal access catheter and standard guide catheter, and the clinical prognosis of patients in the 
balloon guide catheter group was also better than that of the other two groups, and the rates of 
functional independence were 253/415 [61%] vs. 23/55 [42%] vs. 113/218 [52%] [14]. 
However, controversies existed regarding the use of balloon guide catheter. For example, 
Bourcier R et al reported that balloon-guide catheter may be unnecessary with used with a 
combination of aspiration catheter and stent, and the rates of recanalization (60.1% VS 62.7%; 
RR, 0.92; 95%CI, 0.80-1.14) and functional outcome (44.6% Vs 40.0%; RR 1.12, 95%CI, 0.85-
1.47) were similar between BGC group and standard guide catheter group [18]. In addition, some 
technical issues may hinder the widespread use of balloon guide catheters. The stiffness and 
trackability of the catheter may result in complications, also preparing and delivering the BGCs 
may prolonged procedure time and increase of the cost of the procedure [19]. These issues have 
aroused debates on whether balloon guide catheter should be routinely used in thrombectomy 
treatment, which led to absence of standardized procedures for thrombectomy[20, 21]. 
Because of the above reasons, there is an urgent need for a high-quality randomized trial to assess 
the effectiveness of BGC in thrombectomy for acute stroke due to large vessel occlusion and to 
standardize the procedure of mechanical thrombectomy. We aimed at establishing the best 
thrombectomy technique and procedure for AIS due to LVO, so as to improve the clinical 
prognosis, and reduce the national economy burden. 
2 
Study Objective 
The objective of this study is to determine the effectiveness of balloon guide catheter(BGC) as 
compared to standard guide catheter on functional outcome (modified Rankin Scale [mRS] score 
at Day 90) in patients with acute ischemic stroke due to anterior circulation large vessel occlusion. 
3 
Study Design 
This is a prospective, multicenter, randomized controlled, open-label, blinded outcome 
assessment trial involving 1074 eligible subjects to be recruited from 40-60 hospitals in China. 
Subjects who meet the eligibility criteria will be randomized to either intervention group 
(receiving treatment with BGC) or control group (receiving treatment with standard guide 
catheter). Followed up would be conducted at 1 day, 7 days, and 90 days after thrombectomy. 

 
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Study design is presented as below (Figure 1). 
Figure 1. Study schema 
 
4 
Study Population 
Subjects who are with AIS due to LVO of the anterior circulation confirmed by cranial imaging 
and judged to be eligible for being treated with mechanical thrombectomy according to local 
guidelines will be enrolled into this study. The principal investigator at each site will be 
responsible for subject screening and enrollment. 
4.1 Inclusion Criteria 
To be eligible for inclusion for this study, subjects are to satisfy all of the following criteria:  
1) Age ≥18 years. 
2) Diagnosis of AIS with confirmed anterior circulation LVO (including intracranial 
segment of the internal carotid artery, and the first or proximal second segment [M1 or 
proximal M2] of the middle cerebral artery) by brain imaging. 
3) To receive MT within 24 hours after AIS onset according to local guidelines. 
4) Preoperative mRS score of 0-1. 
AIS+LVO patients 
Baseline, Day 1, Day 7  
Clinical and imaging data collection 
R 
Day 90 functional outcome 
mRS score 
Intervention group 
Balloon-guide catheter (stent retriever, 
aspiration, or both) 
Control group 
Standard guide catheter (stent 
retriever, aspiration, or both) 
Standard 
nursing 
and 
medical 
care 
(Local 
Guidelines)

 
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5) Signed informed consent form obtained from the subject (or approved surrogate). 
4.2 Exclusion Criteria 
Subjects who meet any of the following criteria should be excluded from this study: 
1) Intracranial hemorrhage confirmed by imaging. 
2) Known or suspected pre-existing (chronic) large vessel occlusion in the symptomatic 
territory. 
3) Excessive vascular access tortuosity disables the use of balloon guide catheter. 
4) Intracranial stent implanted in the symptomatic territory that precludes the 
deployment/removal of the mechanical thrombectomy device. 
5) Any other condition that precludes the performing of mechanical thrombectomy 
procedure. 
6) Occlusions in multiple vascular territories confirmed by Computed Tomography 
Angiography(CTA) or Magnetic Resonance Angiography(MRA). 
7) Subjects who are pregnant. 
8) Subjects who are allergy to the contrast agent. 
9) Subjects who refuse to cooperate or unable to tolerate interventional operation. 
10) Subjects whose expected lifetime are less than 90 days. 
11) Subjects who are unlikely to participate in follow-up assessments according to the 
investigator’s judgement.  
12) Any other condition that, according to the investigator’s judgement, not suitable for 
using of balloon guide catheter. 
4.3 Subject Withdrawal Criteria 
While study withdrawal is discouraged, subjects may withdraw from the study at any time, with 
or without reason and without prejudice to further treatment. Withdrawn subjects will not 
undergo any additional follow-up, nor will they be replaced, but the collected data may be used 
for statistical analysis. Such withdrawal, including the reason for withdrawal, should be 
documented in the patient’s file.  

 
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4.4 Premature Termination of the Study 
This study could be terminated prematurely by the sponsor (i.e.due to finance or administrative 
reasons et al), regulatory authority, or the ethics committees from the perspective of protecting 
the subjects’ rights and interests. In case of premature termination of the study, no subjects would 
be enrolled, the database will be closed after 90 days assessment of the last enrolled patient and 
results will be reported. 
5 
Randomization and Treatment allocation 
Subjects will be randomized via an Internet-based randomization system in a 1:1 manner to 
treatment with BGCs(Intervention group) or not(control group), stratified by site, preferred 
initial thrombectomy strategy(stent retriever VS aspiration VS stent retriever + aspiration), and 
onset to randomization time( <6 hours VS ≥6 hours). The randomization sequence will use a 
minimization algorithm to ensure balance in key prognostic factors. Randomization is allowed 
when large vessel occlusion has been established. 
Subjects will be treated with thrombectomy based on the results of randomization.  
Intervention group: Subjects treated with BGCs combined with conventional thrombectomy. 
Control group: Subjects treated with standard guide catheter combined with conventional 
thrombectomy. 
Any National Medical Products Administration (NMPA) devices (including the use of a 
thrombectomy stent, distal aspiration catheter, or combine use of both) are allowed. 
6 
Study Method 
6.1 Study Outcomes 
6.1.1 Primary Outcomes 
The primary outcome is functional outcome, defined as modified Rankin Scale (mRS) score shift 
at 90 days (±14 days). 
The modified Rankin Scale (mRS) is an ordinal hierarchical scale ranging from 0 to 5, with 
higher scores indicating more severe disability. A score of 6 has been added to signify death.: 
0 = No symptoms; 
1 = Symptoms, no disability: Minor symptoms that do not interfere with lifestyle; 

 
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2 = Slight disability: Slight disability, symptoms that lead to some restriction in lifestyle, but 
do not interfere with the patient's capacity to look after himself.; 
3 = Moderate disability: Moderate disability, symptoms that significantly restrict lifestyle 
and prevent totally independent existence; 
4 = Moderately severe disability: Moderately severe disability, symptoms that clearly 
prevent independent existence though not needing constant attention; 
5 = Severe disability, totally dependent patient requiring constant attention day and night. 
6 = Death. 
6.1.2 Secondary Outcomes 
1) Dichotomized mRS at 90 days after the procedure (0-1 versus 2-6, 0-2 versus 3-6,0-3 
versus 4-6, 0-4 versus 5-6, 0-5 versus 6); 
2) Change in stroke severity (NIHSS score, the criteria for scoring are detailed in 
Appendix 1) at 24 hours post treatment; 
3) Change in stroke severity (NIHSS score) at 7 days post treatment or discharge 
(whichever occurs first); 
4) Final infarction volume at 5-7 days post treatment; 
5) Technical success rate (defined as successfully navigating the guide catheter into the 
target vessel, and finishing the mechanical thrombectomy procedure without changing 
to another guide catheter); 
6) Reperfusion outcome (eTICI 2b or greater, eTICI 2c or greater, eTICI 3; eTICI criteria 
are detailed in Appendix 2) in final angiogram; 
7) Reperfusion outcome (eTICI 2b or greater, eTICI 2c or greater, eTICI 3) after the first 
pass; 
8) Time from groin puncture to successful reperfusion (eTICI 2b or greater, eTICI 2c or 
greater); 
9) Percentage of subjects with acceptable revascularization quality (eTICI 2b or greater, 
eTICI 2c or greater) within 45 min of access; 
10) Number of thrombectomy attempts (final); 

 
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11) Occurrence of emboli to a new territory. 
6.1.3 Safety Outcomes 
1) Deaths at 90 days (±14 days) post treatment; 
2) Intracranial hemorrhage, symptomatic intracranial hemorrhage or asymptomatic 
intracranial hemorrhage at 7 days post treatment or discharge (whichever occurs first); 
3) Other serious adverse events (SAEs) adjudicated by the Clinical Events Committee; 
4) Any peri-procedural complications, including vessel dissection, arterial perforation, 
and femoral access complications, etc. 
6.1.4 Cost Outcomes 
1) Health-related quality of life using EQ-5D (see Appendix 3); 
2) Utility-weighted mRS scores; 
3) Duration of hospitalization; 
4) Treatment cost. 
6.1.5 Blinding 
Both patient and treating physician will be aware of the treatment assignment. But outcome 
evaluation would be blinded. Information on outcome at 90 days will be assessed through 
standardized forms and procedures, by a trained investigator blinded for treatment allocation. 
Interviews will be recorded. Assessors who are blinded to the treatment allocation will perform 
assessment of outcome on the modified Rankin scale on this information. Results of neuro-
imaging will be also assessed in a blinded manner. Information on treatment allocation will be 
kept separate from the main study database. The steering committee will be kept unaware of the 
results of interim analyses of efficacy and safety. An independent DSMB statistician will 
combine data on treatment allocation with the clinical data in order to report to the data 
monitoring committee (DSMB). 
 
6.2 Study Procedures 
6.2.1 Schedule of Study Activities 

 
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The study procedure is shown in the table below. 
Procedure/Time Window 
Baseline 
1 day post 
treatment 
7 days post 
treatment# 
90 days post 
treatment 
 
Pre-operation - the 
day of treatment* 
±12 hours 
±2 days 
±14 days 
Informed consent 
X 
 
 
 
Demographics 1 
X 
 
 
 
Medical history 2 
X 
 
 
 
Vital signs 3 
X 
X 
X 
 
Blood routine test 4 
X 
X 
 
 
Blood biochemistry 5 
X 
X 
 
 
Coagulation function test 6 
X 
X 
 
 
Imaging examination 7 
X 
X 
X 
 
mRS score8 
X 
 
 
X 
GCS score 9 
X 
X 
X 
 
NIHSS score 10 
X 
X 
X 
 
Quality of life using EQ-
5D 11 
 
 
 
X 
Inclusion/exclusion criteria 
evaluation 12 
X 
 
 
 
Randomization and 
thrombectomy treatment 13 
X 
 
 
 
Medical cost 
 
 
X 
X 
Safety evaluation 14 
X 
X 
X 
X 
Concomitant medication 15 
X 
X 
X 
X 
Notes: #: at discharge or 7 days post treatment, whichever occurs first. *: The end date of surgery will be 
considered as the day of surgery. 
1. 
Demographics: Age, sex, height and weight; 
2. 
Medical history: Including medical history of stroke, carotid artery disease, cardiac disorders, peripheral 
arterial disease, hypertension, diabetes mellitus, and hypercholesterolaemia et al, stroke risk factors 
including history of smoking, alcohol drinking etc, and history of allergy (allergen); 
3. 
Vital signs: Pulse, blood pressure, respiration rate, and body temperature; 
4. 
Blood routine: Red blood cells (RBC) count, white blood cells (WBC) count, neutrophils count, 
lymphocytes count, monocytes count, platelets (PLT) count, and hemoglobin (HGB); 
5. 
Blood biochemistry: Creatinine (Cr), blood urea or blood urea nitrogen (Urea/BUN), and glucose (Glu); 
6. 
Coagulation function: Prothrombin time (PT), activated partial thromboplastin time (APTT), and 
international normalized ratio (INR); 

 
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7. 
Imaging examination: Data of brain imaging examinations (such as CT/CTA, MRI/MRA or DSA) 
performed at each visit will be collected; 
8. 
mRS score: mRS score of subjects before this onset and mRS score at 90 days post treatment will be 
collected; 
9. 
GCS score: GCS scores immediately before randomization, and at 1 day and 7 days post treatment will 
be collected; 
10. NIHSS score: NIHSS scores immediately before randomization, and at 1 day and 7 days post treatment 
will be collected; 
11. Quality of life using EQ-5D: EQ-5D quality of life score at 90 days post treatment will be collected. 
12. Inclusion/exclusion criteria evaluation: Subjects will be evaluated for eligibility using the inclusion 
and exclusion criteria after signing the informed consent form, to determine whether they can be 
randomized; 
13. Randomization and thrombectomy treatment: Subjects will be randomized to the intervention group 
and the control group at the ratio 1:1 after confirming the eligibility, and receive thrombectomy treatment 
in the intervention group or control group according to the result of randomization. Information related 
to thrombectomy treatment will be collected and recorded, which include but not limited to: information 
of product used for embolectomy, technical success rate, reperfusion outcome in final angiogram and 
after the first pass, time from femoral artery puncture to successful reperfusion, revascularization quality 
within 45 minutes, mechanical embolectomy attempts (final), and occurrence of emboli to a new territory, 
etc.; 
14. Safety evaluation: All-cause death, intracranial hemorrhage, other SAEs, and procedure-related 
complications during the study will be collected; 
15. Concomitant medication: including thrombolytics, anticoagulants, antiplatelets, blood pressure/lipid 
and blood glucose control medications taken by the subjects during the study, and concomitant 
medications associated with any SAE. 
 
6.2.2 Study Visits 
The study consists of a total of 4 visits, including: Visits at baseline (pre-procedure~ the day of 
treatment), 1 day (±12 hours) post treatment, 7 days (±2 days) post treatment or at discharge, and 
90 days (±14 days) post treatment. 
6.2.2.1 Visit 1: Baseline Visit (Pre-operation to the Day of Treatment) 
At baseline, subjects will firstly be screened for the study. Each site should keep log of all AIS 
patients with LVO confirmed by brain imaging arriving <24 hours of symptom onset (or last 
known well) and who were considered for the study but subsequently excluded. The screening 
log will record patients’ initials and date of admission together with a brief description of the 

 
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main reason as to why a patient was not randomized. The log will be used by the Research 
Coordinator, PI and the CCC to monitor recruitment and to identify specific barriers to 
randomisation of eligible patients. The investigator should introduce the potential subjects or 
approved surrogates about the purpose of the study and the contents in the informed consent 
form (ICF). Data collection would begin only when both the subject or his/her surrogate and the 
investigator have signed and dated on the ICF. 
The following information will be collected for subjects at this visit: 
1) Date of signature on ICF. 
2) Demographics: Age, sex, height and weight. 
3) Medical history: Including medical history of stroke, carotid artery disease, cardiac 
disorders, hypertension, diabetes mellitus, and hypercholesterolaemia et al, stroke risk 
factors including history of smoking, alcohol drinking etc, and history of allergy 
(allergen). 
4) Vital signs: Pulse, blood pressure, respiration rate, and body temperature. 
5) Laboratory tests: 
a) Blood routine: Red blood cells (RBC) count, white blood cells (WBC) count, 
neutrophils count, lymphocytes count, monocytes count, platelets (PLT) count, and 
hemoglobin (HGB). 
b) Blood biochemistry: Creatinine (Cr), blood urea or blood urea nitrogen 
(Urea/BUN), and glucose (Glu). 
c) Coagulation function: Prothrombin time (PT), activated partial thromboplastin time 
(APTT), and international normalized ratio (INR). 
6) Imaging examination: Data of brain imaging examinations (such as CT/CTA, 
MRI/MRA or DSA) performed at this visit will be collected. 
7) mRS score: mRS score of the subjects before this onset will be collected. 
8) Glasgow Coma Scale (GCS) score: GCS score immediately before randomization will 
be collected. 
9) NIHSS score: NIHSS score immediately before randomization will be collected. 

 
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10) Inclusion/exclusion criteria evaluation: Eligibility of the subjects will be evaluated 
according to the inclusion and exclusion criteria after obtaining signed informed consent 
form, to determine whether they can be randomized. 
11) Randomization and thrombectomy treatment: subjects will be randomized via an 
Internet-based randomization system in a 1:1 manner to treatment with 
BGCs(Intervention group) or not(control group), stratified by site, preferred 
thrombectomy strategy(stent retriever VS aspiration VS stent retriever + aspiration), 
and onset to randomization time( <6 hours VS ≥6 hours) 
Information related to thrombectomy procedure will be collected and recorded, which 
include but not limited to: Information of product used for thrombectomy, technical 
success rate, reperfusion outcome in final angiogram and after the first pass, time from 
femoral artery puncture to successful reperfusion, revascularization quality within 45 
minutes, thrombectomy attempts (final), and occurrence of emboli to a new territory, 
etc. 
12) Safety evaluation: All-cause death, intracranial hemorrhage, other SAEs, and 
procedure or device related complications experienced by subjects during the study will 
be collected. 
13) Concomitant medication: Thrombolytics, anticoagulants, antiplatelets, blood 
pressure/lipid and blood glucose control medications taken by the subjects during the 
study, and concomitant medications associated with any SAE will be collected. 
6.2.2.2 Visit 2: 1 day (±12 hours) post treatment 
The following information will be collected from the subjects at this visit: 
1) Vital signs: Pulse, blood pressure, respiration rate, and body temperature; 
2) Laboratory tests: 
a) Blood routine: Red blood cells (RBC) count, white blood cells (WBC) count, 
neutrophils count, lymphocytes count, monocytes count, platelets (PLT) count, and 
hemoglobin (HGB); 
b) Blood biochemistry: Creatinine (Cr), blood urea or blood urea nitrogen (Urea/BUN), 
and glucose (Glu); 

 
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c) Coagulation function: Prothrombin time (PT), activated partial thromboplastin time 
(APTT), and international normalized ratio (INR); 
3) Imaging examination: results of imaging examinations such as CT scan will be collected; 
4) GCS score; 
5) NIHSS score; 
6) Safety evaluation: All-cause death, intracranial hemorrhage, other SAEs, and procedure-
related complications experienced by subjects during the study will be collected; 
7) Concomitant 
medication: 
Thrombolytics, 
anticoagulants, 
antiplatelets, 
blood 
pressure/lipid and blood glucose control medications taken by the subjects during the 
study, and concomitant medications associated with any SAE will be collected. 
6.2.2.3 Visit 3: 7 days (±2 hours) post treatment or at Discharge 
The following information will be collected for subjects at this visit: 
1) Vital signs: Pulse, blood pressure, respiration rate, and body temperature; 
2) GCS score; 
3) NIHSS score; 
4) Imaging examination: Data of imaging examinations such as CT scan will be collected; 
5) Medical cost; 
6) Safety evaluation: All-cause death, intracranial hemorrhage, other SAEs, and procedure-
related complications experienced by subjects during the study will be collected; 
7) Concomitant 
medication: 
Thrombolytics, 
anticoagulants, 
antiplatelets, 
blood 
pressure/lipid and blood glucose control medications taken by the subjects during the 
study, and concomitant medications associated with any SAE will be collected. 
6.2.2.4 Visit 4: 90 days (±14 days) post treatment 
1) mRS; 
2) Quality of life evaluation using EQ-5D; 
3) Medical cost; 

 
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4) Safety evaluation: All-cause death, intracranial hemorrhage, other SAEs, and procedure-
related complications experienced by subjects during the study will be collected; 
5) Concomitant 
medication: 
Thrombolytics, 
anticoagulants, 
antiplatelets, 
blood 
pressure/lipid and blood glucose control medications taken by the subjects during the 
study, and concomitant medications associated with any SAE will be collected. 
 
7 
Statistical Analysis 
7.1 Sample Size 
In a meta-analysis comparing BGC with standard guide catheter, the use of balloon guide catheter 
improved the proportion of functional outcome by 10.8%[22]. In this study, based on a more 
conservative estimate, we assume the usage of BGC would improve the function outcome by 
8%.  
Based on the distribution of the mRS in the control group of the trial, which we derived from the 
intervention group of the MR CLEAN trial: mRS0: 3%; mRS 1: 9%; mRS 2: 21%; mRS 3: 18%; 
mRS 4: 22%; mRS 5: 6% and mRS 6:21%. We assumed a favorable treatment effect with a 
common odds ratio (cOR) of 1.43, corresponding to an 8% absolute increase in the rate of mRS 
scores of 0-2. In a simulation with 5000 runs we computed the proportion of positive trials, for 
a given sample size. A sample size of 1074 subjects is estimated to be able to demonstrate this 
treatment effect with 87% power and 5% type-1 error. This sample size also allows for 5% 
dropout rate and 5% crossover rate. 
 
7.2 Methods for Statistical Analysis 
Analyses will be performed based on the intention-to-treat (ITT) principle. Baseline data by 
treatment allocation will be reported with statistical procedures. Missing values for baseline 
characteristics will be reported. Missing baseline characteristics will be imputed using regression 
imputation as appropriate. The primary outcome will be analyzed by means of an ordinal logistic 
regression. Pre-defined subgroups will be analyzed by testing for interaction between the specific 
baseline characteristic and treatment. Any reported SAE or discontinuation of assigned treatment 
due to an SAE will be classified using MedDRA.  

 
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Statistical analyses will be detailed in the pre-specified Statistical Analysis Plan (SAP). 
The study consists of 2 interim analyses to be performed when 30% and 60% of the 90-day 
follow- up data have been collected. The independent data and safety monitoring board (DSMB) 
will adopt the Haybittle-Peto rule, and α <0.001 in the interim analysis will be considered as 
statistically significant. Because only 2 interim analyses will be performed, the conventional 
significance level (α= 0.0482) will be used for final analysis. The DSMB will monitor SAEs 
(e.g. death, spontaneous intracerebral hemorrhage [sICH], and neurological deterioration) 
periodically, and the occurrence of excessive SAEs will trigger discussion regarding termination 
of the study.  
 
8 
Study Monitoring 
Qualified Clinical Research Associates (CRAs) will be responsible for regular monitoring of this 
study according to the monitoring plan. The monitoring is to ensure that all parties involved in 
the clinical study comply with the requirements in the Good Clinical Practice (ICH-GCP/GCP) 
and other applicable regulations during the implementation of the study, to protect the rights of 
the subjects and ensure the compliance with the clinical study protocol/procedures, as well as 
the authenticity, completeness and accuracy of the collected data. 
Monitoring procedures include one or more visits before study initiation, regular monitoring 
visits during the study according to the agreed frequency of monitoring, and monitoring visits 
related to site closure after the end of the study.  
 
9 
Data Management 
9.1 Data Collection 
Electronic data capture (EDC) system will be used in this study, collected data will be 
entered into the electronic case report form (eCRF) by the investigator or authorized staff, who 
will receive extensive training prior to data entry. Measures will be taken to ensure the 
information security.  
The investigators are responsible for maintaining all original documents. A complete eCRF 
for each enrolled subject, regardless of the duration of his/her participation, should be submitted 

 
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by the investigators or authorized staff. All supporting documents (e.g., laboratory records or 
records of various clinical research organizations) submitted with the eCRF would be marked 
with study number, all personal privacy information (including subject names) would be 
confidential to protect the privacy of the subjects. 
9.2 Data Entry and amendment 
Investigators and authorized staff would be responsible for data entries, corrections and 
amendments. Any change to the data will be documented, i.e. reason for change, name of 
operator, and the time and date of change should be documented. Any correction to the data in 
the eCRF should signed by the investigators. When there was doubt about the collected data, 
CRA or data management personnel will raise the query in the EDC system, it is the 
responsibility of the investigators to answer the query. The EDC system will document the audit 
trail, including the investigator's name, time and date of the query. 
9.3 Lock of Database 
After verified by the data management personnel, principal investigator (PI), statistician, and 
study monitoring personnel, the data administrators will lock the database. Generally, the locked 
database should not be changed. 
9.4 Transfer of Database 
The locked database will be transferred to statistician for statistical analysis according to 
statistical analysis plan, who will develop the statistical analysis report after completing the 
statistical analysis. 
 
10 Adverse Events/Serious Adverse Events 
10.1 Adverse Events (AEs) 
10.1.1 Definition of Adverse Events 
Adverse events (AE) are any untoward medical occurrence in the clinical investigation, 
whether or not considered to be related to the device / procedure. 
10.1.2 Classification of Adverse Events 
1) Classification by the severity of AE 

 
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The course, severity, treatment and outcome of AEs should be monitored carefully and recorded 
in the AE reporting form. The severity of an AE can be classified as mild, moderate, or severe 
according to the following criteria. 
Table 10-1 Adverse Events by Severity 
Severity 
Description 
Mild 
Transient or mild discomfort, with no limitation of activity, and no medical 
intervention/treatment required. 
Moderate 
Obvious limitation of activity, often requiring assistance, medical 
intervention/treatment, and hospitalization may be necessary. 
Severe 
Extreme limitation of activity, requiring significant assistance and significant 
medical intervention/treatment, and requiring hospitalization or probably 
requiring hospice care. 
2) Classification by relationship of AE to the study device/procedure: 
For all collected AEs, the relationship of the AE to the study device or procedure will be 
determined by the investigator based on temporal relationship and his/her clinical judgment. The 
following categories will be used for grading relevance. 
Criteria for a causal relationship of AE and the Study Device or Procedure: 
1) AE follows a fair temporal sequence from the study device or procedure; 
2) 
The event is a known effect of the study device or the procedure, or a possible effect 
can be explained by the mechanism of the study device or the procedure; 
3) 
The event relieves or ceases after stopping use of the device or procedure; 
4) 
The event reappears after reuse of the device or procedure; 
5) 
The event could not be explained by other contributing factors. 
Any event meeting five items of the criteria above will be considered as "definitely related"; 
while any event meeting two of the criteria above will be considered as "possibly related". 
Criteria for a relationship unrelated to the Study Device or Procedure: 
1) 
AE follows a fair temporal sequence from the study device or procedure ; 
2) 
This type of adverse events is impossible to be caused by the study device or surgical 
procedure;  

 
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3) 
The adverse event can be explained by the concomitant use of other device/drug, 
subject's disease progression, or other treatment effects. 
Any event meeting three items of the criteria above will be considered as "definitely unrelated"; 
while any event meeting one of the criteria above will be considered as "unlikely related". 
Among which, events whose causal relationship is judged as definitely related or possibly related 
will be considered as related to the study device or procedure. 
10.1.3 Recording and Follow up of Adverse Events 
The investigator or authorized staff will document serious adverse events and procedure-related 
complications occurring at any time during the study after the subject has signed the informed 
consent form. Any serious adverse event or procedure-related complication should be treated and 
followed up until the event has been reasonably resolved (e.g. symptoms recovered, resolved, or 
reach to a stable state, or can be well-explained). All treatments and results for SAEs and 
procedure-related complications must be documented appropriately on the CRF. 
10.2 Serious Adverse Event (SAE) 
10.2.1 Definition of Serious Adverse Events 
Any serious adverse event (SAE) that occurs during the study will be recorded by the investigator 
from the time that the study treatment is started for the subject. SAE reporting and notification 
requirements are based on the International Conference on Harmonization-Good Clinical 
Practice (ICH-GCP) guidelines. According to the WHO International Centre for Drug 
Monitoring (1994), a SAE is defined as any of the following untoward medical events which: 
1) Results in death; 
2) Is life threatening in the view of the principal investigator (i.e. its occurrence places the 
patient or subject at immediate risk of death. It does not include an adverse event, had 
it occurred in a more severe form, might have caused death); 
3) Requires inpatient hospitalization or prolongation of existing hospitalization; 
4) Results in a persistent or significant disability or incapacity; 
5) Result in congenital anomaly or birth defects; 
6) Important medical events that may not result in death, be life-threatening, or require 
hospitalizations but may jeopardize the subject and may require medical or surgical 

 
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intervention to prevent one of the outcomes listed above according to the principal 
investigator. 
Notes: Any hospital admission planned due to existed illness or disease before enrolment, or as 
required by the study when the subjects did not experience health deterioration, are not 
considered as a SAE. 
10.2.2 Reporting of Serious Adverse Events 
In case of a SAE, the investigator should immediately take appropriate treatment for the subject; 
meanwhile the investigator should report the SAE, within 24 hours after awaring of it, to the 
ethics committee and the sponsor, and follow up the SAE as required in the protocol and submit 
follow-up and summary reports as required. 
11 Ethical Considerations 
11.1 Ethical Requirements in Relevant Regulations 
This clinical study must be conducted in compliance with Declaration of Helsinki, and other 
applicable regulations. The study can be initiated only after the files such as the study protocol 
and ICF have been approved by the ethics committee of the site. 
For every subject, before being enrolled in this study, the investigator is responsible for giving 
him/her or his/her surrogate a complete and comprehensive introduction to the objectives, 
procedures and possible risks of this study, and they should be made aware that they can 
withdraw from the study at any time. Then, the ICF will be signed by the subject or his/her 
surrogate and the investigator, and the signed ICF should be retained as a clinical study document 
for inspection. 
Before initiation of this clinical study, the investigator should submit this clinical study protocol, 
ICF, and other relevant documents to the ethics committee. This study can only be initiated after 
being approved by the Ethics Committee. Any amendment to the protocol must be approved by 
the Ethics Committee before implementation. Any SAE occurring during the clinical study 
should be reported to the Ethics Committee in writing within 24 hours after the investigator's 
awareness of the event. 
Before the start of the study in each clinical trial institution, the Ethics Committee of the principal 
sites are responsible for reviewing the ethical appropriateness, rationality and scientificity of the 
study protocol. The ethics committees of other sites should review feasibility of the study in their 

 
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institutions by means of conference or document review, when accepting the review comments 
of the ethics committee of the principal site, including the qualification and experience of the 
investigators, study equipments and conditions, etc. 
The ethics committees shall supervise the clinical study in their corresponding clinical trial 
institutions, and may require to suspend or terminate the study at any time via written notification 
if it finds that the subjects’ rights and interests cannot be guaranteed. 
The clinical study, once suspended, shall not be resumed without the approval of the Ethics 
Committee. 
Should any SAE occur in this study, the investigator should immediately take appropriate 
treatment measures for the subject; meanwhile a written report shall be submitted to the Ethics 
Committee of the site. 
11.2 Informed Consent 
Before a subject agrees to participate, the investigator should fully explain the details of this 
study, including the purpose, contents, and procedures as well as the possible risks and benefits 
of this study, to the subject or the surrogate and/or the impartial witness (according to local 
regulations). After a full and detailed explanation, the ICF will be signed and dated by the subject 
or his/her surrogate and/or the impartial witness (according to local regulations) as well as the 
investigator. 
The ICF will be signed in duplicates by the investigator and the subject or his/her guardian and/or 
a third-party witness, with each keeping one copy. 
11.3 Approval of the Study Protocol 
The ethics committee is responsible for the review and approval of this clinical study protocol, 
and the study could not be initiated until final approval is obtained from the ethics committee. 
 
12 Quality Control of the Study 
12.1 Investigators Training 
Prior to the start of the study, the investigators will be trained on the study protocol by a CRA 
designated by the sponsor. 
12.2 Measures to Improve Subjects Compliance 

 
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The investigator should conduct informed consent carefully to ensure that the subjects fully 
understand the study requirements and cooperate during the trial. 
12.3 Clinical Monitoring 
The CRAs designated by the sponsor will perform on-site monitoring visits regularly to ensure 
that the study protocol is strictly followed and to check the consistency of the contents in the 
eCRF with the source data. 
12.4 Data Management 
The eCRF should be completed as soon as possible during or after the visit and updated timely 
to ensure that it reflects the latest status of the subjects in the study. The investigator should 
review the data to ensure the accuracy and correctness of all data entered into the eCRF. If some 
assessments are not performed during the study, or some information is unavailable, not 
applicable, or unknown, the investigator should also record it in the eCRF. The investigator shall 
electronically sign on the completed and verified CRF/the verified data. 
12.5 Maintenance of Source Documents 
Source documents refer to all documents of the subjects used by the investigator or the clinical 
study institution, which can prove the existence of the subjects, the inclusion and exclusion 
criteria, and records for their participation in this study, including laboratory records, and subject 
folder, etc. 
The clinical study institution, investigator and sponsors shall establish a retention system of 
essential documents. The study essential documents can be divided into three parts based on the 
phase of the study, i.e. files in the preparing phase, ongoing phase, and termination or completion 
phase. The clinical study institution should properly retain the study records and essential 
documents as agreed with the sponsor. 
Source documents for this study include signed informed consent forms, laboratory test reports, 
operation records of each subject, and other relevant records. 
 
13 Study Administration 
13.1 Organizational Structure 
The study consists of a steering committee (SC) of experts in the therapeutic field who are 

 
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responsible for the oversight of the study. CCRC Medtech (Shanghai) Co., Ltd. will serve as the 
central coordinating center (CCC), to be responsible for the organization and operation of the 
study. The specific work of the committee is described below. 
13.1.1 Steering Committee 
Responsibilities: Responsible for the overall study design, protocol implementation, data 
collection, analysis plan and subsequent publication. The Committee can appoint new members 
and co-elect other members to enhance the integrity of the research and analysis work. 
Members: Core members of the steering committee are listed below and other members will be 
specified in the charter of the committee. 
! 
Professor Jianmin Liu (Co-Principal Investigator), The First Affiliated Hospital of 
Naval Medical University（Changhai hospital）, China; 
! 
Professor Mayank Goyal (Co-Principal Investigator), University of Calgary Cumming 
School of Medicine. 
! 
Professor Pengfei Yang, The First Affiliated Hospital of Naval Medical University
（Changhai hospital）, China; 
 
13.1.2 Central Coordinating Center (CCC) 
CCRC Medtech (Shanghai) Co., Ltd. will serve as the CCC. 
Responsibilities of CCC: Daily administration of the study, data and project management, 
committee coordination, assistance in applications to ethics committees, training of participating 
sites on the study protocol and procedures, site initiation visits, monitoring of data quality and 
compliance with applicable guidelines and regulations. 
13.1.3 Imaging Adjudication Committee (Core Laboratory) 
Responsibilities: De-identification of images, and independent assessment of all imaging data of 
CT/CTA, MRI/MRA, and DSA. 
13.1.4 Clinical Events Committee (CEC) 
Responsibilities: Review the SAEs and procedure related complications, to ensure the criteria 
for evaluation are consistent. 

 
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13.1.5 Data and Safety Monitoring Board (DSMB) 
Responsibility: Review the safety, ethicality and study results throughout the study. 
13.1.6 Outcome Assessment Committee (OAC) 
Responsibilities: independent assessment of the primary outcome (mRS score) in blinded manner. 
13.2 List of Study Sites 
The study, leading by The First Affiliated Hospital of Naval Medical University（Changhai 
hospital）, is planned to be conducted at 40-60 sites in China. A list of all participating sites will 
be provided separately. 
13.3 Confidentiality Principle 
This protocol is a confidential document provided to the study team members including the 
medical experts and investigators in this study, as well as medical institutions, ethics committees, 
CROs and other concerned institutions undertaking this trial. Except for explaining relevant 
information to the subjects, no part of this protocol can be made public or disclosed to any third 
party without prior written consent of the sponsor. In addition, the results of this study, regardless 
of in part or as a whole, can only be presented to any society or published in any journal after 
receiving written consent of the sponsor. 
The clinical study agreement, the contents of this clinical study and all supplementary materials 
are confidential and exclusively owned by the sponsor. The investigator should keep confidential 
of the information including patent application, manufacturing process and unpublished data 
provided by the sponsor, etc., and shall not disclose any information to the third party unless 
agreed by the sponsor. This confidentiality obligation remains effective after the termination or 
end of this study. 
The personal data of the subjects collected by the investigator and his/her staff for use in this 
study (“study data"), include date of birth, sex, identity card, home address, photographs, and 
personal data regarding physical or mental health status of the subjects. 
All medical records and study materials that can identify the subjects should be kept confidential 
to the extent permitted by law. However, the investigator, the sponsor and its representatives, the 
CRAs (the persons responsible for monitoring how the study is conducted and ensuring that the 
information is collected correctly), and in certain specific circumstances, regulatory authorities 

 
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and ethics committees may inspect and copy confidential information that identifies the subjects. 
All personal information in the study will be handled in accordance with the national and local 
laws on data protection. 
Subjects have the right to request the investigator and the sponsor to protect their information 
and to correct any inaccuracies in these data. If a subject withdraws consent, the investigator will 
no longer use or disclose the subject's data to others, but the sponsor may still use the study data 
obtained before withdrawal. 
The results of this study may be published in medical journals and presented at medical meetings. 
Subjects will not be identified in any of these publications. 
13.4 Agreement on the Publication of Study Results 
The main results of this study will be published in the name of the PROTECT-MT Collaborative 
Research Group. Publication of the results will be managed and controlled primarily by a writing 
committee designated by the SC. 
The investigator can publish or present the study results. However, as this is a multi-center study, 
the investigator must agree that: interim results of the study may not be published or presented 
without prior written permission of the SC. In addition, the investigator must agree that: notify 
SC at least 30 days prior to submission of the study results for publication or presentation, and 
provide a summary of the study results report or a copy of the manuscript (including but not 
limited to text, PPT slides, and any other translated text or media materials). SC shall review and 
provide comments on the publications, abstracts, slides and manuscripts; review and comment 
on the accuracy of the information; protect the rights of any individual; ensure fairness and 
compliance with the applicable regulations. 
In the event of disagreement between the parties regarding the appropriateness and/or 
confidentiality of the data analysis and presentation, the investigator shall agree to meet with SC 
members at the study site or as otherwise agreed to discuss and resolve any disagreement prior 
to submission for publication. 
 
14 Fund 
This study is funded by Shanghai Shenkang Hospital Development Center , Biopharma 
Industry Promotion Center Shanghai and Zhuhai TonBridge Medical Technology Co., Ltd.  

 
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15 Appendix 
Appendix 1: NIHSS Scale 
The NIHSS is an ordinal hierarchical scale that evaluates the severity of stroke by assessing the 
patient's physical strength. Scores may range from 0 to 42, with higher scores indicating more 
severe ischemia. Administer stroke scale items in the order listed. Record performance in each 
category after each subscale exam. Do not go back and change scores. Follow directions 
provided for each exam technique. Scores should reflect what the patient does, not what the 
clinician thinks the patient can do. The clinician should record answers while administering the 
exam and work quickly. Except where indicated, the patient should not be coached (i.e., repeated 
requests to patient to make a special effort). 
Instructions 
Scale Definition 
1a. Level of Consciousness. The investigator must 
choose a response if a full evaluation is prevented by 
such obstacles as an endotracheal tube, language 
barrier, orotracheal trauma/bandages. A 3 is scored 
only if the patient makes no movement (other than 
reflexive 
posturing) 
in 
response 
to 
noxious 
stimulation. 
0=Alert; keenly responsive. 
1=Not alert; but arousable by minor 
stimulation to obey, answer, or respond. 
2=Not alert; requires repeated stimulation to 
attend, or is obtunded and requires strong or 
painful stimulation to make movements (not 
stereotyped). 
3=Responds only with reflex motor or 
autonomic effects, or totally unresponsive, 
flaccid, and areflexic. 
1b. Level of Consciousness Questions: The patient is 
asked the month and his/her age. The answer must be 
correct - there is no partial credit for being close. 
Aphasic and stuporous patients who do not 
comprehend the questions will score 2. Patients unable 
to speak because of endotracheal intubation, 
orotracheal trauma, severe dysarthria from any cause, 
language barrier, or any other problem not secondary 
to aphasia are given a 1. It is important that only the 
initial answer be graded and that the examiner not 
"help" the patient with verbal or non-verbal cues. 
0=Answers both questions correctly. 
1=Answers one question correctly. 
2=Answers neither question correctly. 
1c. LOC Commands: The patient is asked to open 
and close the eyes and then to grip and release the non-
0=Performs both tasks correctly. 
1=Performs one task correctly. 

 
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paretic hand. Substitute another one-step command if 
the hands cannot be used. Credit is given if an 
unequivocal attempt is made but not completed due to 
weakness. If the patient does not respond to command, 
the task should be demonstrated to him or her 
(pantomime), and the result scored (i.e., follows none, 
one, or two commands). Patients with trauma, 
amputation, or other physical impediments should be 
given suitable one-step commands. Only the first 
attempt is scored. 
2=Performs neither task correctly. 
2. Best Gaze: Only horizontal eye movements will be 
tested. Voluntary or reflexive (oculocephalic) eye 
movements will be scored, but caloric testing is not 
done. If the patient has a conjugate deviation of the 
eyes that can be overcome by voluntary or reflexive 
activity, the score will be 1. If a patient has an isolated 
peripheral nerve paresis (CN III, IV, or VI), score a 1. 
Gaze is testable in all aphasic patients. Patients with 
ocular trauma, bandages, pre-existing blindness, or 
other disorder of visual acuity or fields should be 
tested with reflexive movements, and a choice made 
by the investigator. Establishing eye contact and then 
moving about the patient from side to side will 
occasionally clarify the presence of a partial gaze 
palsy. 
0=Normal. 
1=Partial gaze palsy; gaze is abnormal in 
one or both eyes, but forced deviation or total 
gaze paresis is not present. 
2=Forced deviation, or total gaze paresis is 
not overcome by the oculocephalic maneuver. 
3. Visual: Visual fields (upper and lower quadrants) 
are tested by confrontation, using finger counting or 
visual threat, as appropriate. Patients may be 
encouraged, but if they look at the side of the moving 
fingers appropriately, this can be scored as normal. If 
there is unilateral blindness or enucleation, visual 
fields in the remaining eye are scored. Score 1 only if 
a clear-cut asymmetry, including quadrantanopia, is 
found. If patient is blind from any cause, score 3. 
Double simultaneous stimulation is performed at this 
point. If there is extinction, patient receives a 1, and 
0=No visual loss. 
1=Partial hemianopia. 
2=Complete hemianopia. 
3=Bilateral hemianopia (blind including 
cortical blindness). 

 
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the results are used to respond to item 11. 
4. Facial Palsy: Ask or use pantomime to encourage 
the patient to show teeth or raise eyebrows and close 
eyes. Score symmetry of grimace in response to 
noxious stimuli in the poorly responsive or non-
comprehending patient. If facial trauma/bandages, 
orotracheal tube, tape, or other physical barriers 
obscure the face, these should be removed to the 
extent possible. 
0=Normal symmetrical movements. 
1=Minor paralysis (flattened nasolabial fold, 
asymmetry on smiling). 
2=Partial paralysis (total or near-total 
paralysis of lower face). 
3=Complete paralysis of one or both sides 
(absence of facial movement in the upper and 
lower face). 
5. Motor Arm: The limb is placed in the appropriate 
position: extend the arms (palms down) 90 degrees (if 
sitting) or 45 degrees (if supine). Drift is scored if the 
arm falls before 10 seconds. The aphasic patient is 
encouraged using urgency in the voice and 
pantomime, but not noxious stimulation. Each limb is 
tested in turn, beginning with the non-paretic arm. 
Only in the case of amputation or joint fusion at the 
shoulder, the examiner should record the score as 
untestable (UN) and clearly write the explanation for 
this choice. 
0=No drift; limb holds 90 (or 45) degrees for 
full 10 seconds. 
1=Drift; limb holds 90 (or 45) degrees, but 
drifts down before full 10 seconds; does not 
hit bed or other support. 
2=Some effort against gravity; limb cannot 
get to or maintain (if cued) 90 (or 45) degrees, 
drifts down to bed, but has some effort against 
gravity. 
3=No effort against gravity; limb falls. 
4=No movement. 
UN=Amputation or joint fusion: explain: 
5a=left arm. 
5b=right arm. 
6. Motor Leg: The limb is placed in the appropriate 
position: hold the leg at 30 degrees (always tested 
supine). Drift is scored if the leg falls before 5 
seconds. The aphasic patient is encouraged using 
urgency in the voice and pantomime, but not noxious 
stimulation. Each limb is tested in turn, beginning with 
the non-paretic leg. Only in the case of amputation or 
joint fusion at the hip, the examiner should record the 
score as untestable (UN) and clearly write the 
explanation for this choice. 
0=No drift; leg holds 30-degree position for 
full 5 seconds. 
1=Drift; leg falls by the end of the 5- second 
period but does not hit the bed or other 
support. 
2=Some effort against gravity; leg falls to 
bed by 5 seconds but has some effort against 
gravity. 
3=No effort against gravity; leg falls to bed 
immediately. 
4=No movement. 
UN=Amputation or joint fusion: explain: 
6a. Left leg 

 
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6b. Right leg. 
7. Limb Ataxia: This item is aimed at finding 
evidence of a unilateral cerebellar lesion. Test with 
eyes open. In case of visual defect, ensure testing is 
done in intact visual field. The finger-nose-finger and 
heel-shin tests are performed on both sides, and ataxia 
is scored only if present out of proportion to weakness. 
Ataxia is absent in the patient who cannot understand 
or is paralyzed. Only in the case of amputation or joint 
fusion, the examiner should record the score as 
untestable (UN) and clearly write the explanation for 
this choice. In case of blindness, test by having the 
patient touch nose from extended arm position. 
0= Absent. 
1=Present in one limb. 
2=Present in two limbs. 
UN=Amputation or joint fusion: explain: 
8. Sensory: Sensation or grimace to pinprick when 
tested, or withdrawal from noxious stimulus in the 
obtunded or aphasic patient. Only sensory loss 
attributed to stroke is scored as abnormal and the 
examiner should test as many body areas [arms (not 
hands), legs, trunk, face] as needed to accurately 
check for hemisensory loss. A score of 2, "severe or 
total sensory loss," should only be given when a 
severe or total loss of sensation can be clearly 
demonstrated. Stuporous and aphasic patients will, 
therefore, probably score 1 or 0. The patient with 
brainstem stroke who has bilateral loss of sensation is 
scored 2. If the patient does not respond and is 
quadriplegic, score 2. Patients in a coma (item 1a=3) 
are automatically given a 2 on this item. 
0=Normal; no sensory loss. 
1=Mild-to-moderate sensory loss; patient 
feels pinprick is less sharp or is dull on the 
affected side; or there is a loss of superficial 
pain with pinprick, but patient is aware of 
being touched. 
2=Severe or total sensory loss; patient is not 
aware of being touched in the face, arm, and 
leg. 
9. Best Language: A great deal of information about 
comprehension will be obtained during the preceding 
sections of the examination. For this scale item, the 
patient is asked to describe what is happening in the 
attached picture, to name the items on the attached 
naming sheet, and to read from the attached list of 
sentences. Comprehension is judged from responses 
here, as well as to all of the commands in the 
0=No aphasia; normal. 
1=Mild-to-moderate aphasia; some obvious 
loss of fluency or facility of comprehension, 
without significant limitation on ideas 
expressed or form of expression. Reduction 
of speech and/or comprehension, however, 
makes conversation about provided materials 
difficult or impossible. For example, in 

 
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preceding general neurological exam. If visual loss 
interferes with the tests, ask the patient to identify 
objects placed in the hand, repeat, and produce speech. 
The intubated patient should be asked to write. The 
patient in a coma (item 1a=3) will automatically score 
3 on this item. The examiner must choose a score for 
the patient with stupor or limited cooperation, but a 
score of 3 should be used only if the patient is mute 
and follows no one-step commands. 
conversation 
about 
provided 
materials, 
examiner can identify picture or naming card 
content from patient's response. 
2=Severe aphasia; all communication is 
through fragmentary expression; great need 
for inference, questioning, and guessing by 
the listener. Range of information that can be 
exchanged is limited; listener carries burden 
of communication. Examiner cannot identify 
materials provided from patient response. 
3=Mute, global aphasia; no usable speech or 
auditory comprehension. 
10. Dysarthria: If patient is thought to be normal, an 
adequate sample of speech must be obtained by asking 
patient to read or repeat words from the list in the 
attachment. If the patient has severe aphasia, the 
clarity of articulation of spontaneous speech can be 
rated. Only if the patient is intubated or has other 
physical barriers to producing speech, the examiner 
should record the score as untestable (UN) and clearly 
write the explanation for this choice. Do not tell the 
patient why he/she is being tested. 
0=Normal. 
1=Mild-to-moderate dysarthria; patient 
slurs at least some words and, at worst, can be 
understood with some difficulty. 
2=Severe dysarthria: patient's speech is so 
slurred as to be unintelligible in the absence 
of or out of proportion to any dysphasia, or is 
mute/anarthric. 
UN=Intubated or other physical barrier. 
11. Extinction and Inattention (formerly Neglect): 
Sufficient information to identify neglect may be 
obtained during the prior testing. If the patient has a 
severe 
visual 
loss 
preventing 
visual 
double 
simultaneous stimulation, and the cutaneous stimuli 
are normal, the score is normal. If the patient has 
aphasia but does appear to attend to both sides, the 
score is normal. The presence of visual spatial neglect 
or anosagnosia may also be taken as evidence of 
abnormality. Since the abnormality is scored only if 
present, the item is never untestable. 
0=No abnormality. 
1=Visual, tactile, auditory, spatial, or 
personal inattention, or extinction to 
bilateral simultaneous stimulation in one of 
the sensory modalities. 
2=Profound hemi-inattention or extinction 
to more than one modality; does not 
recognize own hand or orients to only one 
side of space. 
 
 
 

 
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Appendix 2: eTICI Scale 
Grade Short description 
Long description 
0 
No perfusion 
No antegrade flow beyond the point of occlusion. 
1 
Minimal perfusion 
The antegrade flow passes the area of obstruction but there is 
little or slow reperfusion flow in the distal branches. 
2a 
Reperfusion <50% 
Antegrade flow fills less than 50% of the ischemic areas of 
target vessel occlusion (e.g., 1 important branch of the middle 
cerebral artery and its territory). 
2b 
50% ≤ Reperfusion <90% 
Antegrade flow fills more than 50% of the ischemic areas of 
target vessel occlusion (e.g., 2 important branches of the middle 
cerebral artery and their territories). 
2c 
Reperfusion ≥90% 
Reperfusion antegrade flow almost completely fill the whole 
ischemic areas of the target vessel occlusion, with only slow 
flow or thrombus in a small portion of the distal vessel branches. 
3 
100% reperfusion 
Reperfusion antegrade flow completely fill the whole ischemic 
areas of the target vessel occlusion, with no visible occlusion in 
the distal branches. 
 
 
 

 
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Appendix 3: EQ-5D Health-Related Quality of Life Scale 
Date of score: |__|__|/|__|__|/|__|__|__|__| (DD/MM/YYYY) 
Item 
Score 
Mobility 
□ I have no problems in walking about 
□ I have slight problems in walking about 
□ I have moderate problems in walking about 
□ I have severe problems in walking about 
□ I am unable to walk about 
Self-care 
□ I have no problems washing or dressing myself 
□ I have slight problems washing or dressing myself 
□ I have moderate problems washing or dressing myself 
□ I have severe problems washing or dressing myself 
□ I am unable to wash or dress myself 
Usual activities 
□ I have no problems doing my usual activities 
□ I have slight problems doing my usual activities 
□ I have moderate problems doing my usual activities 
□ I have severe problems doing my usual activities 
□ I am unable to do my usual activities 
Pain/Discomfort 
□ I have no pain or discomfort 
□ I have slight pain or discomfort 
□ I have moderate pain or discomfort 
□ I have severe pain or discomfort 
□ I have extreme pain or discomfort 
Anxiety/Depression 
□ I am not anxious or depressed 
□ I am slightly anxious or depressed 
□ I am moderately anxious or depressed 
□ I am severely anxious or depressed 
□ I am severely anxious or depressed 
Status that best describes your 
health 
Score _________ (0-100) 
 
 

 
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