A Retrospective Post-Market Clinical Study of the Flow Re-Direction Endoluminal Device System in the Treatment of Intracranial Aneurysms
Conditions: Intracranial Aneurysm
Sponsor: Microvention-Terumo, Inc.

MicroVention, Inc 
Clinical Study Protocol 
 
Protocol ID：CL1106094 
Revision：A, Date: Jan 21, 2025 
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Clinical Study Protocol for Medical Devices 
 
A Retrospective Post-Market Clinical Study of the Flow Re-Direction 
Endoluminal Device System in the Treatment of Intracranial Aneurysms 
 
 
Observational Device: 
 
Flow Re-Direction Endoluminal Device System 
 
Model/Specification: Refer to section 2.2.1 in this Protocol 
Management Category of 
Observational Device: 
Class Ⅲ Medical Device subject to clinical 
study approval 
Yes□ 
No ☒ 
Similar product in China 
Yes☒ 
No□ 
Protocol Version and Date: Version A, 2025-01-21 
Clinical Research Institution 
(Leading Institutions): 
Henan Provincial People's 
Hospital 
The First Affiliated Hospital of 
Zhengzhou University 
Coordinating Investigator: Tianxiao Li 
Sheng Guan 
Sponsor: MicroVention. Inc 
Agent: 
 
MicroVention (Beijing) Medical Technology Co., Ltd 
 
 
Confidentiality Statement 
This study protocol contains confidential information and is intended solely for use by clinical investigators. This 
document is the property of MicroVention, Inc. The information not publicly disclosed in this document must not 
be disclosed without the prior written approval of MicroVention, Inc. This document is intended only for the 
relevant parties. 
 
 

MicroVention, Inc 
Clinical Study Protocol 
 
Protocol ID：CL1106094 
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Approver Signature Page 
 
Department 
 
Name and Title 
 
Signature & Date 
 
Clinical Research & Operation 
 
Brook Li 
Manager, Clinical Research & 
Operation, China 
（Author） 
 
Medical Affairs 
 
Sheila Warner 
Sr Director，Medical Affairs 
 
Global Clinical & Medical Affairs 
 
Nagesh Uppuluri 
SVP, Global Clinical & Medical 
Affairs 
 
Regulatory Affairs 
 
Crystal Nie 
Director, Regulatory Affairs & 
Regulatory Compliance (China) 
 
Biostatistics 
 
 
 
Dr. Dong ChongYa 
Senior Biostatistician, Peking 
University Clinical Research Institute 
 

MicroVention, Inc 
Clinical Study Protocol 
 
Protocol ID：CL1106094 
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Principal Investigator Signature 
 
Study Site Name 
 
PI Signature 
 
Date 
 
 
 
 
 

MicroVention, Inc 
Clinical Study Protocol 
 
Protocol ID：CL1106094 
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Table of Contents 
Table of Contents ................................................................................................................................ 4 
List of Abbreviations .......................................................................................................................... 7 
Protocol Synopsis ............................................................................................................................... 8 
1 Sponsor Information ..................................................................................................................... 12 
1.1 Sponsor Name ...................................................................................................................... 12 
1.2 Sponsor Address ................................................................................................................... 12 
1.3 Name, Address, Contact Information and Qualification Documents of the Agent .............. 12 
2 Clinical Study Background .......................................................................................................... 13 
2.1 Design Background .............................................................................................................. 13 
2.1.1 Disease Explanation .................................................................................................. 13 
2.1.2 Treatment Options ..................................................................................................... 13 
2.1.3 Observational Device ................................................................................................ 14 
2.2 Basic Composition of the Observational Device ................................................................. 14 
2.2.1 Structural Composition ............................................................................................. 14 
2.2.2 Principle of Operation and Mode of Action .............................................................. 16 
2.3 Scope of Application and Relevant Information .................................................................. 16 
2.3.1 Indication(s) .............................................................................................................. 16 
2.3.2 Applicable Sites......................................................................................................... 16 
2.3.3 Mode and Duration of Contact with Human Body ................................................... 16 
2.3.4 Applicable Disease Stage and Intensity .................................................................... 16 
2.3.5 Condition of Use ....................................................................................................... 16 
2.3.6 Reuse ......................................................................................................................... 16 
2.3.7 Directions for Use ..................................................................................................... 17 
2.3.8 Contraindications ...................................................................................................... 17 
2.3.9 Precautions and Warnings: ........................................................................................ 17 
3 Clinical Study Objective ............................................................................................................... 17 
4 Clinical Study Design .................................................................................................................... 17 
4.1 Overall Design and Selection Rationale .............................................................................. 17 
4.1.1 Number of Patients Required for Clinical Study and Rationale ............................... 17 
4.1.2 Expected Overall Duration of Clinical Study ........................................................... 18 
4.2 Patient Selection ................................................................................................................... 18 
4.2.1 Inclusion Criteria....................................................................................................... 18 
4.2.2 Exclusion Criteria ..................................................................................................... 18 
4.3 Date Collection .................................................................................................................... 18 
4.3.1 Demographic data and other baseline characteristics ............................................... 18 
4.3.2 Medical History......................................................................................................... 18 
4.3.3 Information of Procedure .......................................................................................... 18 
4.3.4 Information of follow up ........................................................................................... 19 
4.4 Endpoint ............................................................................................................................... 19 
4.4.1 Safety Endpoint ......................................................................................................... 19 
4.4.2 Efficacy Endpoint ..................................................................................................... 21 
4.4.3 Rationale for Evaluation Endpoints Selection .......................................................... 22 

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4.5 The Data Collection Schedule .............................................................................................. 23 
4.6 Bias Control Measures ......................................................................................................... 23 
5 Statistical Considerations ............................................................................................................. 24 
5.1 Sample Size Estimation ....................................................................................................... 24 
5.2 Statistical Analysis Datasets................................................................................................. 25 
5.3 Statistical Analysis Methods ................................................................................................ 25 
5.3.1 Statistical Analysis Plan ............................................................................................ 25 
5.3.2 General Principle of Statistical Analysis ................................................................... 25 
5.3.3 Baseline Analysis ...................................................................................................... 25 
5.3.4 Endpoint analyses ..................................................................................................... 25 
5.4 Stage Analysis ...................................................................................................................... 25 
5.5 Management of Missing and Abnormal Values ................................................................... 26 
5.6 Criteria for Eligible/Ineligible Clinical Study Results ......................................................... 26 
6 Data Management ......................................................................................................................... 26 
6.1 Data Capture ........................................................................................................................ 26 
6.2 Data Entering and Modification ........................................................................................... 26 
6.3 Database Lock ...................................................................................................................... 26 
6.4 Database Transfer ................................................................................................................. 27 
7 Factors Influencing Study Success and Failure ......................................................................... 27 
7.1 Factors Influencing Study Success ...................................................................................... 27 
7.2 Factors Influencing Study Failure ........................................................................................ 27 
8 Quality Control of Clinical Study ................................................................................................ 28 
8.1 Investigator Training ............................................................................................................ 28 
8.2 Data Management ................................................................................................................ 28 
8.3 Setting Clinical Events Committee ...................................................................................... 28 
9 Ethical Considerations and Informed Consent of Clinical Study ............................................ 28 
9.1 Ethical Considerations ......................................................................................................... 28 
9.2 Patient Inform Consent Process ........................................................................................... 28 
10 Adverse Event, Serious Adverse Event ..................................................................................... 29 
10.1 Adverse Event .................................................................................................................... 29 
10.1.1 Definition ................................................................................................................ 29 
10.1.2 Determination of Severity ....................................................................................... 29 
10.1.3 Determination of Causality Relationship Between AEs and Devices AE .............. 29 
10.1.4 Reporting and Follow-up ........................................................................................ 29 
10.2 Serious Adverse Event ....................................................................................................... 30 
10.2.1 Definition ................................................................................................................ 30 
10.2.2 Reporting of SAEs .................................................................................................. 30 
11 Clinical Event Committee ........................................................................................................... 30 
12 Protocol Amendments ................................................................................................................. 31 
13 Direct Access to Source Data and Documentation ................................................................... 31 
14 Clinical Study Report ................................................................................................................. 31 
15 Principle of Confidentiality ........................................................................................................ 31 
16 Responsibilities of All Parties ..................................................................................................... 32 
16.1 Responsibilities of Sponsor ................................................................................................ 32 

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16.2 Responsibilities of Medical Device Clinical Research Institutions ................................... 33 
16.3 Responsibilities of Investigators ........................................................................................ 34 
17 Miscellaneous Issues to be Clarified .......................................................................................... 34 
17.1 Finance and Insurance ........................................................................................................ 34 
17.2 Agreement on Study Result Publication ............................................................................ 34 
Investigator Statement ..................................................................................................................... 35 
References ......................................................................................................................................... 36 
List of Figures 
Figure 2-1 FRED System Setup ......................................................................................................... 15 
Figure 2-2 FRED Implant Nomenclature ........................................................................................... 15 
 
List of Tables 
Table2-1 List of Specifications and Models  .................................................................................... 15 
Table 4-1 Raymond-Roy Classification Standards ............................................................................ 21 
Table 4-2 Modified Rankin Scale (mRS) ........................................................................................... 22 
 

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List of Abbreviations 
Abbreviation 
Full Term 
AE 
Adverse Event  
APTT 
Activated Partial Thromboplastin Time  
CEC 
Clinical Event Committee  
CI 
Confidence Interval  
CRA 
Clinical Research Associates  
CRO 
Contract Research Organization  
CTA 
Computed Tomography Angiography  
CS 
Clinically Significant 
CSR 
Clinical Study Report 
DSA 
Digital Subtraction Angiography 
EC 
Ethics Committee  
eCRF 
electronic Case Report Form  
EDC 
Electronic Data Capture 
FD 
Flow Diverter  
FIB 
Fibrinogen  
FRED 
Flow Re-Direction Endoluminal Device  
GCP 
Good Clinical Practice  
IA 
Intracranial Aneurysms  
ICF 
Informed Consent Form  
IFU 
Instructions For Use  
MRA 
Magnetic Resonance Angiography  
mRS 
modified Rankin Scale 
NMPA 
National Medical Products Administration  
OKM 
O’Kelly-Marotta 
PD 
Protocol Deviation  
PED 
Pipeline Embolization Device  
PI 
Principal Investigator  
PT 
Prothrombin Time  
SAE 
Serious Adverse Event  
SAH 
Subarachnoid Hemorrhage  
SAP 
Statistical Analysis Plan 
SAR 
Statistical Analysis Report 
SDV 
Source Data Verification 
TEG 
thromboelastographic 
TT 
Thrombin Time  
UIA 
Unruptured Intracranial Aneurysms  
 

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Clinical Study Protocol 
 
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Protocol Synopsis 
Sponsor 
 
MicroVention, Inc. 
Study Title 
 
A retrospective, post-market clinical study of the flow re-direction endoluminal 
device system in the treatment of intracranial aneurysms. 
 
Protocol No. 
 
CL1106094 
Version/Date 
 
Version A, 2025-01-21 
 
Study Objective 
 
To evaluate the long-term safety and efficacy of Flow Re-Direction Endoluminal 
Device System (FRED) in the treatment of intracranial aneurysms in the post-market 
environment 
 
Study Design 
 
Post-market, retrospective, multi-center, observational clinical study 
 
Study Population 
 
Patient who has implanted at least one observational device in China mainland. 
 
Observational Device 
 
Flow Re-Direction Endoluminal Device System (FRED) 
 
Study Duration 
 
About 36 months. 
 
Inclusion and Exclusion 
Criteria 
 
Inclusion Criteria:  
A patient is eligible for inclusion in the study if he/she meets all the following  
1) 
People in China mainland who have been treated with FRED.  
 
2) 
The patients for whom clinical data are available. 
 
Exclusion Criteria:  
Patients who met the inclusion criteria at all time points were required to be included 
in the study. Therefore, no specific exclusion criteria were set. 
 
Data Collection 
 
Demographic data and other baseline characteristics人口统计学数据和其他基
线特征 
 
Birth date 
 
Sex: Male/ Female  
 
History of smoking and drinking: Yes/No  
 
Ethnicity: Han/ another ethnicity  
 
Diagnosis  
 
Modified Rankin Scale (mRS) 
 
Physical Examination: Neurological physical examination.  
 

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Medical History 
 
Past medical history: including current medical conditions (high blood 
pressure, diabetes, etc.), history of cranial and neurological related surgeries, 
hemorrhagic stroke.  
Information of Procedure 
 
Before Procedure 
- 
Aneurysm Information: aneurysm location (left/right, C2 petrous segment 
- C7 terminus), aneurysm size (aneurysm maximum diameter, aneurysm 
neck, width, dome to neck ratio) and morphology (saccular aneurysm, 
dissecting aneurysm, fusiform aneurysm), ruptured / unruptured/ 
recurrent and the information of the parent artery (dimeter, stenosis) [Base 
Computed Tomography Angiography(CTA)]. 
- 
laboratory examination (clinically significant abnormal results only). 
- 
Information of antiplatelet function test result: platelet aggregation test/ 
Thromboelastographic (TEG); 
- 
Information of anti-coagulation and anti-platelet medication: drug name, 
dosage and frequency of administration. 
 
Using information of device 
- 
Microcatheter: product name, model, size 
- 
Coil usage: Yes/No and number 
- 
Balloon: Yes/No and number 
- 
FRED: number, model, lot number  
 
 
Information of procedure 
- 
Puncture position (femoral artery/radial artery, left/right)  
- 
Re-sheathing performance: whether re-sheathing after release, re-
sheathing times, re-sheathing success or not  
- 
Imaging results of immediate post-operation: stent fully cover the 
aneurysm neck, good wall apposition, parent artery perfusion, retention 
of contrast media. 
- 
Procedure complication: Complications of arterial puncture including 
pain, local bleeding, or injury to the artery, or adjacent nerves. Dissection 
or perforation of the parent artery, Rupture or perforation of the aneurysm, 
Vasospasm, Stent thrombosis, et al.  
 
 
Information of follow up 
- 
Imaging Evaluation of a Target Aneurysm: Digital Subtraction 
Angiography (DSA), Magnetic Resonance Angiography (MRA), CTA 

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can be accepted. 
- 
Treatment-related 
hospitalization 
information 
or 
adverse 
event 
information: Stroke, Death, Adverse Event, Serious Adverse Event. 
 
Endpoint 
 
Safety Endpoints[Adjudicated by Clinical Event Committee (CEC)]  
1) 
troke Rate  
2) 
All-cause Mortality  
 
3) 
Lesion-Related Symptoms or Signs Rate 
 
4) 
Lesion-Related Complication Rate (Immediate post-procedure)  
 
5) 
Adverse Event (AE), Serious Adverse Event (SAE) 
 
Efficacy Endpoints 
1) 
Imaging Evaluation of Target Aneurysm [O’Kelly-Marotta(OKM) Grade] 
2) 
Adequate Occlusion Rate of Target Aneurysm (Base Raymond-Roy Grade)  
3) 
Technical Success rate (Immediate post-procedure) 
4) 
Re-sheathing Performance (Immediate post-procedure)  
5) 
Modified Rankin Scale (mRS) Change from Baseline  
 
Statistical Analysis 
Method 
Sample Size Estimation 
This study is an observational study that does not involve statistical hypotheses. 
Therefore, the plan is to collect data on as many patients as possible who received 
FRED treatment for intracranial aneurysms in China from May 2023 to May 2027, 
and as such, there is no specific sample size estimation. 
 
Statistical Analysis Datasets 
The dataset will consist of all study patients who meet the inclusion and exclusion 
criteria. 
 
General Principles of Statistical Analysis 
Detailed information on statistical analyses will be described in a separate Statistical 
Analysis Plan (SAP), with the final version of the SAP to be completed prior to 
database lock. 
The statistical analysis will be performed for this study using SAS® (version 9.4 or 

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higher). 
This study is observational in design and does not involve statistical inference or 
hypothesis testing. Descriptive statistics for continuous variables will include the 
number of observations, mean, standard deviation, median, minimum, maximum 
values, and quartiles (Q1, Q3). 
 
Baseline Analysis 
Demographic, clinical characteristics, and treatment information of the patients 
including age, gender, medical history, physical examination, laboratory, surgical 
information, are statistically described. The methodology will adhere to standard 
principles. 
 
Endpoint analyses: 
This study is observational and does not involve statistical inference. 
Descriptive analyses will be conducted on safety and efficacy endpoints. For binary 
endpoints, counts and percentages will be provided, with 95% confidence intervals 
(CIs) estimated using the exact binomial method. Survival endpoints will be 
assessed using the Kaplan-Meier method to estimate survival probabilities and 
calculate the corresponding 95% CIs, accounting for censored data. Continuous 
endpoints will be summarized with counts, means, medians, standard deviations, 
minimums, maximums, and interquartile ranges, along with their 95% CIs. 
 
Stage Analysis 
According to the requirements of National Medical Products Administration 
(NMPA), the collected data will be divided according to the following schedule, and 
the statistics and analysis of clinical data during the corresponding collection period 
will be completed once a year: 
- 
During May 2023 to May 2025  
- 
During June 2025 to May 2026  
- 
During June 2026 to May 2027  
 

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1 Sponsor Information 
1.1 Sponsor Name 
MicroVention,Inc 
1.2 Sponsor Address 
35 Enterprise Aliso Viejo, CA 92656 USA 
1.3 Name, Address, Contact Information and Qualification Documents of the Agent 
Name: MicroVention, Beijing 
Address: Units 2 & 3, 1501, floor 15, Building 2, Yard 2, Jianguomenwai Street, Chaoyang District, 
Beijing, China 
Contact information: 
Contact name: Daisy Ding, Manager, Regulatory Affairs – China 
Contact phone number: 10-84400992 
E-mail: daisy.ding@microvention.com 
 
Contact name: Brook Li, Manager, Clinical Research & Operations – China 
Telephone: 13891855337 
Email: brook.li@microvention.com 
 
 

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2 Clinical Study Background 
2.1 Design Background 
2.1.1 Disease Explanation 
Intracranial Aneurysms (IAs) are abnormal bulges that caused by localized vascular wall damage in 
intracranial arteries. The prevalence of IAs in the general population is estimated to be approximately 
3%-5%. Once an aneurysm ruptures, leading to Subarachnoid Hemorrhage (SAH), the mortality rate 
can reach up to 40%[1, 2]. 
The symptoms of IA can manifest as neurological dysfunction caused by mass effect or thrombosis, 
but the most common clinical presentation is SAH, typically presents with a sudden, severe headache 
and may be accompanied by transient loss of consciousness, vomiting, neck pain or stiffness[3]. Most 
Unruptured Intracranial Aneurysms (UIA) lack specific clinical symptoms and are often discovered 
incidentally, with only a few detected due to symptoms such as headaches or ptosis. Some patients 
with unruptured aneurysms may present with symptom, including visual disturbances (due to 
compression of the optic nerve), cranial nerve palsies (especially third nerve palsy), corticospinal 
tract dysfunction, and facial pains[4].  
2.1.2 Treatment Options 
The main principle of treating IAs is to exclude the aneurysm from the circulation to prevent rupture 
or re-rupture. There are two main treatment strategies: surgical clipping via craniotomy and 
endovascular treatment. The ideal endovascular treatment shall achieve complete aneurysm occlusion 
while preserving the parent artery. With this technique, a microcatheter is introduced via a 
transfemoral approach and manipulated into the cerebral aneurysm under fluoroscopic guidance. 
Following catheterization of the aneurysm, multiple detachable coils are placed within the aneurysm 
fundus, inducing aneurysm thrombosis, and again isolating the aneurysm fundus from the parent 
artery circulation[1]. 
Traditional endovascular techniques focus on intra-aneurysmal embolization, with primary methods 
including simple coil embolization and stent-assisted coiling. However, the effectiveness of these 
techniques is often constrained by the morphological characteristics of the aneurysm. Wide-neck 
aneurysms (defined as a neck width ≥ 4 mm or a dome-to-neck ratio < 2) are particularly challenging 
to treat. By utilizing coils for physical packing of the aneurysmal sac, the lack of effective support at 
the aneurysm neck often results in coil prolapse into the parent artery. This can lead to compromised 
blood flow to distal regions supplied by the parent artery, causing neurological deficits and severely 
affecting the patient's clinical outcomes. 
Flow Diverter (FD) devices are developed based on reconstructing the parent artery’s lumen. FDs are 
designed with a denser mesh compared to conventional intracranial stents. By covering the aneurysm 
neck, these stents redirect blood flow away from the aneurysm, promoting intra-aneurysmal flow 
stagnation and subsequent thrombosis formation. Currently, FDs are primarily used for the treatment 
of wide-neck aneurysms[1]. 
At present, there are two major flow diverter devices in use. The first is the SILK, developed by BALT. 
The SILK device consists of a stent made from 48 braided nitinol and platinum alloy wires. The stent 

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delivery system comprises both the stent and a microcatheter, and the stent can be retrieved before 
90% of deployment. SILK has been approved for marketing in the European Union. The second 
device is the Pipeline Embolization Device (PED), manufactured by Medtronic in the United States, 
which is similarly composed of 48 braided nitinol-platinum-iridium alloy wires. Its basic components 
are like those of the SILK device. PED has been approved for use in the EU, by the U.S. FDA, and 
by China’s NMPA. 
2.1.3 Observational Device 
The design of the observational device Flow Re-Direction Endoluminal Device (FRED) system is 
comparable to other approved devices with the same or similar indications. FRED has been approved 
for use by the U.S. FDA on December 16, 2019, and received market approval from China’s NMPA 
on May 12, 2022, with registration number 国械注进20223130235. The self-expanding nitinol stent 
is the implantable portion of the Flow Re-Direction Endoluminal Device (FRED) system. The stent 
consists of two integrated nitinol braided inner and outer layers with the outer layer containing flare 
ends. The inner layer is of lower porosity, braided in a 36-wire format using 36 individual wires 
(FRED 2.5 mm and 3.0 mm), or 48 wire formats using 48 individual wires (FRED 3.5 mm to 5.5 
mm). The outer stent layer is of higher porosity, braided in a 16-wire format using a single wire that 
is passed around a mandrel 16 times. Two radiopaque wires are inter-woven between the outer and 
inner layers along the length of the inner layer implant in a helix configuration. There are four 
radiopaque markers at each end of the stent. 
The FRED system features a dual-layer stent design. The inner stent is similar in design to the SILK 
and PED devices, while the outer stent is designed with similar materials and structure to coil-assist 
stents currently in use, such as the LVIS™ (MicroVention), the Neuroform™ Stent System (Boston 
Scientific) and the Enterprise™ Vascular Reconstruction Device (Johnson & Johnson).  
This clinical study is conducted in accordance with NMPA requirements to evaluate the long-term 
follow-up safety information of FRED following its market release. 
 
2.2 Basic Composition of the Observational Device 
2.2.1 Structural Composition 
The FRED System [see Figure 2-1 and Figure 2-2] consists of a self-expanding nickel-titanium 
implant and a delivery system. The implant is designed to expand to a pre-determined diameter when 
released from the delivery system. The implant features integrated dual layer coverage designed to 
focus mainly on the neck of an intracranial aneurysm. The implant has distal and proximal markers 
on its ends and interweaved helical marker strands delineating the inner working length of the implant 
to provide fluoroscopic visibility. 
The FRED System is packaged sterile as a single unit with the implant, introducer sheath and a 
detachable delivery pusher. It is available in 7 different implant diameters ranging from 2.5 mm to 
5.5 mm and in different implant lengths ranging from 13 mm to 45 mm. The FRED System 2.5 mm 
and 3.0 mm implants are compatible with the Headway 21 Microcatheter (FRED-21 System). The 
FRED System 3.5 mm to 5.5 mm implants are compatible with the Headway 27 Microcatheter 
(FRED-27 System). 

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Figure 2-1 FRED System Setup 
 
 
Figure 2-2 FRED Implant Nomenclature 
Table2-1 List of Specifications and Models  
Device 
Outer Diameter (mm) 
 
Total Lengths (mm) 
 
Working Lengths (mm) 
 
FRED System 
FRED 
 
2.5 
13~30 
8~26 
3.0 
13~32 
9~27 
3.5 
13、17、22、31、40 
7、11、16、24、36 
4.0 
13、18、23、32、44 
7、12、17、26、38 
4.5 
15、20、25、34、45 
8、13、18、28、39 
5.0 
15、21、26、36 
9、14、19、29 
5.5 
22、32 
14、26 
Specifications and Models of Product(s) to be Used in Combination 
 
Microcatheter 
 
Lengths 
 
Minimum inner diameter 
of guide duct 
Recommended Guide 
 
Headway 17 
150 cm 
0.056 inch / 1.42 mm 
≤ 0.014 inch/ ≤ 0.36 mm 
Headway 21 
150 cm 
0.056 inch / 1.42 mm 
≤ 0.018 inch / ≤ 0.46 mm 
Headway 27 
150 cm 
0.056 inch / 1.42 mm 
≤ 0.018 inch / ≤ 0.46 mm 
不透射线钽丝标记(N=4) 

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2.2.2 Principle of Operation and Mode of Action 
The observation device is a flow diverter (FD) designed for permanent implantation into the lumen 
of the aneurysm or vascular dissection to carry the aneurysm. The approach site is usually an 
angiography-guided femoral artery. Neurovascular access is obtained according to standard 
endovascular maneuvers. This can be achieved by navigating the guidewire to the location of the 
aneurysm neck or to the target location, and then the microcatheter is navigated through the guidewire. 
After removing the guidewire, select the appropriate size flow guide according to the instructions for 
use (IFU). The instrument is assembled inside a coil and placed in a sterile area. The device 
(implant/delivery pusher/introduction sheath) is removed from the coil as a whole. The blood flow 
guide was inspected and prepared according to the IFU. Follow the "Instructions for Use" in the IFU 
to push the FRED implant into the microcatheter by pushing the delivery guidewire. By delivering a 
guidewire, the implant can advance further through the microcatheter until it reaches the distal tip of 
the microcatheter, but not beyond the microcatheter tip (proximal fluorescent labeling on the FRED 
delivery system can aid in this process). At this point, fluoroscopy must begin. While the implant 
remains within the microcatheter, it is positioned and deployed by aligning its distal radiopaque end 
marker. Once the position has been determined under fluoroscopy, the microcatheter is retracted and 
the delivery guidewire is advanced to allow the FRED implant to unfold in the aneurysm neck. If the 
implant is not fully deployed, it can be retracted and repositioned if necessary. Once deployed, the 
implant expands and clings to the wall of the blood vessel and across the neck of the aneurysm. 
 
2.3 Scope of Application and Relevant Information 
2.3.1 Indication(s) 
The FRED System is indicated for use in the internal carotid artery from the petrous segment to the 
terminus for the endovascular treatment of adult patients (22 years of age or older) with wide-necked 
(neck width ≥ 4 mm or dome-to-neck ratio < 2) saccular or fusiform intracranial aneurysms arising 
from a parent vessel with a diameter ≥ 2.0 mm and ≤ 5.0 mm. 
2.3.2 Applicable Sites 
Internal carotid artery from the petrous segment to the terminus.  
2.3.3 Mode and Duration of Contact with Human Body 
Prolonged and continuous blood contact (>30 days). 
2.3.4 Applicable Disease Stage and Intensity 
Intracranial aneurysms. 
2.3.5 Condition of Use 
Sterile medical environment.  
2.3.6 Reuse 
Sterile delivery, single use only. 

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2.3.7 Directions for Use 
Please refer to Instructions for Use (IFU). 
2.3.8 Contraindications 
Use of the FRED System is contraindicated under these circumstances:  
• 
Patients in whom anticoagulant, anti-platelet therapy, or thrombolytic drugs are contraindicated. 
• 
Patients with known hypersensitivity to metal such as nickel-titanium and metal jewelry. 
• 
Patients with anatomy that does not permit passage or deployment of the FRED System. 
• 
Patients with an active bacterial infection.  
• 
Patients with a pre-existing stent in place at the target aneurysm.  
• 
Patients in whom the parent vessel size does not fall within the indicated range. 
• 
Patients who have not received dual anti-platelet agents prior to the procedure. 
2.3.9 Precautions and Warnings:  
Please refer to Instructions for Use (IFU). 
3 Clinical Study Objective 
To evaluate the long-term safety and efficacy of post-marketing of Flow Re-Direction Endoluminal 
Device System (FRED) in the treatment of intracranial aneurysms. 
4 Clinical Study Design 
4.1 Overall Design and Selection Rationale 
This is a post-market, retrospective, multi-center, observational clinical study. 
The study plans to enroll patients who meet the eligibility criteria and have received at least one 
implantation of the observational device between May 2023 and May 2027. The retrospective data 
will be collected on baseline characteristics, information of procedure, and safety and efficacy 
endpoint to assess the safety and efficacy of FRED in the Chinese population. The efficacy endpoints 
include technical success rates and re-sheathing performance, the complete occlusion rate, and 
modified Rankin Scale (mRS) change from baseline. The safety endpoints include the rates of stroke, 
mortality, lesion-related symptoms or signs rate, lesion-related complication rate, adverse event, 
serious adverse event. 
4.1.1 Number of Patients Required for Clinical Study and Rationale 
No restrictions. 
 
The eligible patients will be included between May 2023 and May 2027, without limiting the sample 
size of patients. This approach aligns with the NMPA requirements, which state, “Each product 
implanted in a patient shall be registered, and all patients implanted with the product shall be followed 

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up for a long time”. By not imposing a limit on the number of enrolled patients, the study ensures that 
all eligible patients can participate, enabling a comprehensive assessment of the safety and efficacy 
of the FRED. 
Moreover, this flexible recruitment strategy enhances sample diversity, allowing for a more accurate 
reflection of real-world clinical applications. A larger and more varied sample will facilitate a 
thorough analysis of outcomes across different patient demographics and conditions, ultimately 
strengthening the reliability of the study’s findings and their applicability in clinical practice. 
4.1.2 Expected Overall Duration of Clinical Study 
About 36months. 
4.2 Patient Selection 
4.2.1 Inclusion Criteria 
A patient is eligible for inclusion in the study if he/she meets all the following criteria: 
1) 
People in China mainland who have been treated with FRED. 
2) 
The patients for whom clinical data are available. 
4.2.2 Exclusion Criteria 
Patients who met the inclusion criteria at all time points were required to be included in the study. 
Therefore, no specific exclusion criteria were set. 
4.3 Date Collection 
4.3.1 Demographic data and other baseline characteristics 
 
Birth date 
 
Sex: Male/ female 
 
History of smoking and drinking: Yes/No 
 
Ethnicity: Han/ another ethnicity 
 
Diagnosis 
 
Physical Examination: Modified Rankin Scale (mRS), neurological physical examination. 
4.3.2 Medical History 
 
Past medical history: including current medical conditions (high blood pressure, diabetes, etc.), 
History of cranial and neurological related surgeries, hemorrhagic stroke.  
4.3.3 Information of Procedure 
 
Before Procedure 
- 
Aneurysm Information (Target): aneurysm location (left/right, C2 petrous segment-C7 
terminus), aneurysm size (aneurysm maximum diameter, aneurysm neck width, dome to 

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neck ratio) and morphology (saccular aneurysm, dissecting aneurysm, fusiform aneurysm), 
ruptured / unruptured / recurrent and the diameter of the parent artery (Base CTA). 
- 
Laboratory Examination(Clinically significant abnormal results only, that means abnormal 
laboratory test results that were judged by the investigator to be different from the normal 
standard values and had certain reference value for the diagnosis of clinical diseases). 
- 
Information 
of Antiplatelet 
Function 
Test 
Result: 
platelet 
aggregation 
test/ 
thromboelastographic (TEG). 
- 
Information of anti-coagulation and anti-platelet medication: drug name, dosage and 
frequency of administration are needed. 
 
Using Information of Device 
- 
Microcatheter: product name, model, size  
- 
Coil Usage: Yes/No and number  
- 
Balloon: Yes/No and number  
- 
FRED: number, model, lot number FRED： 
 
 
Information of Procedure 
- 
Puncture position (femoral artery/radial artery, left/right)  
Re-sheathing Performance: Whether re-sheathing after release, re-sheathing times, re-sheathing 
success or not 
- 
Imaging results of immediate post-operation: stent fully cover the aneurysm neck, good wall 
apposition, parent artery perfusion, retention of contrast media.  
- 
Procedure complication: Complications of arterial puncture including pain, local bleeding, 
or injury to the artery, or adjacent nerves. Dissection or perforation of the parent artery, 
Rupture or perforation of the aneurysm, Vasospasm, Stent thrombosis.  
4.3.4 Information of follow up  
 
Imaging Evaluation of a Target Aneurysm: DSA、MRA、CTA can be accepted. 
 
Treatment-related hospitalization information or adverse event information: Stroke, Death, 
Adverse Event, Serious Adverse Event.  
4.4 Endpoint 
4.4.1 Safety Endpoint 
(1) Stroke Rate 
Definition: The stroke rate refers to the proportion of stroke patients in the total number of patients. 
Collection Content: Record the date of stroke, type (ischemic or hemorrhagic), severity (mild, 
moderate, severe), location and cause, treatments, or other interventions for stroke, and whether the 

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stroke resulted in the patient's death. Also assess the relationship of the stroke event to the 
observational device and the patient's concurrent antithrombotic therapy. All stroke events are 
assessed by the CEC. 
(2) All-cause Mortality 
Definition: Mortality refers to the proportion of dead patients in the total number of patients. 
Collection Content: Record the date of the death event and whether it was neurogenic. Evaluate the 
relationship of the death event to the observational device. Neurogenic death is defined as a death 
event directly resulted from a neurologic cause judged by the Clinical Event Committee (CEC). 
(3) Lesion-Related Symptoms or Signs Rate 
Definition: Lesion-related symptoms or signs rate refers to the proportion of patients with lesion-
related symptoms or signs to total patients. 
Collection Content: All neurological related symptoms which were not present at baseline or 
worsened from baseline will be record including headache, hemiplegic paralysis, seizure, aphasia, 
stroke, bleeding (including intracerebral, subarachnoid hemorrhage, retroperitoneal, others), facial 
nerve pain, seizures, vision loss, aphasia, hemiplegia, oculomotor nerve palsy, neck pain or stiffness, 
loss of consciousness, meningeal irritation, pre-retinal hemorrhage, increased intracranial pressure, 
other aneurysm-related symptoms, or abnormal signs (list specific symptoms or abnormal signs). 
(4) Lesion-Related Complication Rate 
Definition: Lesion-related complication refers to the proportion of patients with lesion-related 
complication to total patients. 
Collection Content: Record whether the following complications occurred during the procedure. 
Principal Investigator (PI) shall evaluate the relationship between complications and observational 
device, other interventional devices, and surgical procedures. 
- 
Complications of arterial puncture: including puncture site pain, puncture site local 
bleeding, injury to the puncture artery or adjacent nerves,； 
- 
Dissection or perforation of the parent artery,  
- 
Rupture or perforation of the aneurysm,  
- 
Vasospasm； 
- 
Stent thrombosis,  
- 
Other complication  
(5) Adverse Event, Serious Adverse Event (AE, SAE) 
Definition: Refer to section 10 in this protocol.  
Evaluation method: All Adverse Events (AEs) observed or reported will be assessed and recorded, 
and the causality and severity of AEs will be assessed according to the definitions and causality 

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assessment in Section 11 of this protocol.   
The Principal Investigator (PI) shall assess whether an AE/ SAE meet the definition of surgical 
complication and safety collection index. If yes, the investigator shall complete corresponding 
surgical complication or safety evaluation indicator page. 
4.4.2 Efficacy Endpoint 
(1) Imaging Evaluation of a Target Aneurysm（O’Kelly-Marotta,（OKM）） 
Definition: Based on the evaluation of imaging results, the treatment of aneurysms was classified 
according to the following criteria. Digital Subtraction Angiography (DSA), Magnetic Resonance 
Angiography (MRA), or Computed Tomography Angiography (CTA) are acceptable, and it is 
recommended base CTA. The purpose of imaging follow-up information collection is to observe the 
effect of on the long-term closure of the aneurysm after treatment. Complete closure of the aneurysm 
would be associated with increased safety.  
 No filling 
 Entry remnant (<5%) 
 Subtotal filling (5%～95%) 
 Total filling (>95%) 
The observational device with the blood flow and the aneurysm gradually closes. The evaluation 
results of different follow-up nodes were counted, and the time interval between the date of surgery 
and the aneurysm occlusion is collected. 
 
(2) Adequate Occlusion Rate of Target Aneurysm 
Definition: Adequate Occlusion is defined as Raymond-Roy Grade I or Grade II on imaging 
evaluation of the target aneurysm [5]. If the Raymond-Roy grade reaches Grade I at any evaluation 
point, no further imaging information will be collected. Imaging results obtained via Digital 
Subtraction Angiography (DSA), Magnetic Resonance Angiography (MRA), or Computed 
Tomography Angiography (CTA) is acceptable. The imaging results will be evaluated following the 
routine procedures of the clinical research institution. The post-procedure recanalization of the 
aneurysm is graded according to the following classification. Please refer to Error! Reference source 
not found. for Raymond-Roy Classification Standards. 
Table 4-1 Raymond-Roy Classification Standards 
Grade 
Description 
Grade I 
Complete occlusion (no contrast filling in the aneurysm sac or neck) 
Grade II 
Neck remnant (contrast filling in the aneurysm neck but not the sac) 
Grade III 
Residual sac (contrast filling in the aneurysm sac) 
Occlusion Rate of Target Aneurysm refers to the proportion of patients judged to be Grade 1 or Grade 
2 in the total number of patients. 
(3) Technical Success Rate 

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Definition: Technical success is defined as successful stent placement and meet following criteria:  
- Stent fully cover the aneurysm neck 
- Good wall apposition 
- Perfusion of the parent artery 
- Retention of contrast agent within the aneurysm. 
The technical success rate refers to the proportion of technically successful patients in the 
total number of patients. 
 
(4) Re-sheathing performance  
Definition: During procedure, the observational device can be retrieved / re-sheathed into the 
microcatheter and re-deployed at the desired target location or removed completely from the patient. 
But it must not be re-deployed more than three times. Re-sheath performance refers to the retrieving 
and re-deploying of observational device recorded during the procedure. Information such as the 
number of recoveries and the number of re-sheathings, the success rate of re-opening and other 
information are recorded to evaluate the re-sheath performance of the observational device. 
 
(5) Modified Rankin Scale (mRS) Change from Baseline 
Definition: At different follow-up, the modified Rankin score changed from the baseline. 
The modified Rankin (mRS) score was used to evaluate the improvement of neurological function. 
The modified Rankin score assesses the ability to live independently in patients with Neurological 
disease [6]. There are 7 levels of this score, 0 points represent no symptoms of disability, higher scores 
mean worse prognosis of patients, and 6 points represent death, See the table below for detailed scores. 
Table 4-2 Modified Rankin Scale (mRS) 
Score 
Patient Condition 
0 
No symptoms of disability 
1 
Minor symptoms but no significant deficits; capable of all activities and work 
2 
Mild disability; unable to participate fully in previous activities but can live independently 
3 
Moderate disability; requires assistance but can walk independently 
4 
Moderate to severe disability; unable to walk independently, cannot live alone, requires some care 
5 
Severe disability; bedridden, incontinent, requires constant care 
6 
Death  
4.4.3 Rationale for Evaluation Endpoints Selection 
Rationale for safety endpoint selection: The safety indicators set for this study aligns with the 
NMPA requirements, which state, "The observation indicators include at least the following: ……, 
related stroke events, and clinical follow-up of deaths, strokes, and disease-related symptoms within 
6 months". The recommendation of Chinese guidelines for the treatment of intracranial aneurysms 
with flow divertor is that the vast majority of occlusion of aneurysms after FD implantation occurs 
within 12 months after treatment. The incidence and severity of AEs/SAEs meet the relevant 
requirements for safety indicators in the Guidelines for Clinical Study Design of Medical Devices. 

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Rationale for efficacy endpoints selection: This clinical study is conducted in accordance with 
NMPA requirements to evaluate the long-term follow-up safety information of FRED following its 
market release. The efficacy indicators set for this study aligns with the NMPA requirements, which 
state, "The observation indicators include at least the following: technical success rate, re- sheathing 
performance, perioperative period". In addition, the observational device FRED features a finer mesh 
design compared to conventional intracranial stents, which allows it to cover the aneurysm neck, 
redirect blood flow, and promote blood stasis within the aneurysm, leading to thrombus formation 
and an increased aneurysm occlusion rate. To evaluate the efficacy of the observational device, the 
clinical study selected the aneurysm occlusion rate as the efficacy endpoint. 
4.5 The Data Collection Schedule 
The data collection schedule is described in  
Table 4-3 Data Collection Plan 
Baseline 
Treatment* 
Follow-Up Information** 
 
Demographic Information1 
 
Medical History2 
 
Physical Examination3 
 
Imaging findings4 
 
Modified Rankin Scale 
 
Aneurysm Information5 
 
Laboratory Examination6 
 
Information of antiplatelet 
function test result: platelet 
aggregation 
test/ 
Thromboelastographic (TEG) 
 
Information 
of 
anti-
coagulation and anti-platelet 
medication7 
 
Using Information of Device 
 
Information of Procedure 
 
Stroke 
 
Mortality 
 
AE/SAE  
 
O’Kelly-Marotta(OKM) 
Grade 
 
Raymond-Roy Grade 
 
Technical Success 
 
Re-sheathing Performance 
 
Physical Examination4 
 
Information 
of 
anti-
coagulation and anti-platelet 
medication7 
 
Image data 
 
Lesion-Related Complication 
 
Stroke 
 
Mortality 
 
AE/SAE 8 
 
O’Kelly-Marotta(OKM) 
Grade 
 
Raymond-Roy grade 
 
Modified Rankin Scale 
Notes: 
1. Demographic Information including: birth date, sex, history of smoking and drinking, ethnicity, diagnosis. 
2. Medical History: Past medical history: including current medical conditions (high blood pressure, diabetes, etc.), 
history of cranial and neurological related surgeries, hemorrhagic stroke. 
3. Physical Examination: neurological physical examination. 
4. Image data collection, per standard of care (e.g., DSA, MRA, CTA) can be applied. 
5. Based on CTA . 
6. Laboratory Examination: Blood routine (red blood cell count, hemoglobin white blood cell count, neutrophil count, 
lymphocytes count, platelet count), coagulation test [Prothrombin Time (PT), Activated Partial Thromboplastin Time 
(APTT), Thrombin Time (TT) and Fibrinogen (FIB) International standardized ratio (INR)]. Only clinically significant 
abnormal results were recorded. 
7. Information on anti-coagulation and anti-platelet medication: drug name, dosage and frequency of administration 
are needed. 
*. If the same patient received other surgical treatments using observational device within the data collection time 
frame, only the first treatment data was selected as the baseline data, and the follow-up time was calculated at this 
point. The remaining surgical treatments were recorded as "concomitant surgery". 
** Each patient may have multiple follow-up information, all of which should be recorded and collected. The collected 
follow-up data will be divided according to the following follow-up points: 30 days after surgery, 3 months after 
surgery, 6 months after surgery, and 1 year after surgery, according to the principle of closest approach. 
4.6 Bias Control Measures 
Multicenter Study: A multicenter design ensures that the case sample is more representative 
compared to a single-center study, thereby reducing the potential for bias caused by systemic errors 

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unique to a single center. This enhances the generalizability of the study results. 
Standardized Data Collection: The eligible patients meeting the inclusion within the specified time 
frame, will be enrolled in this study to avoid selection bias. This ensures the integrity of the population 
under study and minimizes the risk of bias introduced by arbitrary patient selection. 
Training of Data Recorders: Data collection personnel will undergo comprehensive training to 
ensure that all data are captured uniformly, in accordance with predefined data collection protocols 
and eCRF standards. Regular data audits and quality control procedures will be implemented to 
ensure the accuracy, reliability, and completeness of the data. 
Data Review: Prior to database lock, a data review meeting will be initiated by the data management 
team. Attendees will include the principal investigator, the sponsor, data managers, clinical monitors, 
and biostatisticians. The primary objectives will be to finalize the statistical analysis dataset, evaluate 
any unreported AEs, verify any outstanding data queries, and decide on database lock and the formal 
approval of population stratification decisions. 
Investigator Training: All investigators involved in this clinical study are highly experienced in the 
relevant therapeutic area. Prior to study initiation, Clinical Research Associates (CRAs) will conduct 
thorough protocol training sessions to ensure investigators are fully knowledgeable about the study 
design, endpoint definitions, and operational procedures. Investigators will rigorously adhere to the 
inclusion criteria and will document clinical data according to protocol-defined procedures. 
Clinical Study Monitoring: Regular on-site monitoring visits will be conducted to ensure strict 
adherence to the study protocol. Source Data Verification (SDV) will be performed on eCRF to verify 
that the data recorded are consistent with the original source documents. 
Identification of Confounding Variables: Potential confounders will be systematically identified. 
Any variable suspected to be a confounding factor, based on existing evidence, will be carefully 
documented. Factors that may influence both the intervention and the outcome will be thoroughly 
considered, and data collection will be as comprehensive as possible to ensure robust adjustment for 
confounding in the final analysis. 
Clinical Events Committee: Medical data requested in the protocol will be provided to Clinical 
Events Committee under patient information protection for review. The personnel requirements of 
the CEC member and the contact details of the corresponding personnel will be recorded in a separate 
file. Evaluation and adjudication of safety endpoints as specified in the protocol will be completed 
by an independent Clinical Event Committee, and the relevant provisions for evaluation are referred 
to in the Clinical Event Committee bylaws. 
 
5 Statistical Considerations 
5.1 Sample Size Estimation 
Not applicable. 
This study is an observational study that does not involve statistical hypotheses. Therefore, the plan 
is to collect data on as many patients as possible who received FRED treatment for intracranial 
aneurysms in China from May 2023 to May 2027, and as such, there is no specific sample size 

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estimation. 
5.2 Statistical Analysis Datasets 
The dataset will consist of all study patients who meet the inclusion and exclusion criteria. 
5.3 Statistical Analysis Methods 
5.3.1 Statistical Analysis Plan 
Detailed information on statistical analyses will be described in a separate Statistical Analysis Plan 
(SAP), with the final version of the SAP to be completed prior to database lock. Statistical analyses 
will be conducted according to the predefined SAP. Any changes to the statistical methods outlined 
in this protocol before database lock will be documented in SAP. Any modifications to the finalized 
SAP after database lock will be documented in the Statistical Analysis Report (SAR) and Clinical 
Study Report (CSR). 
5.3.2 General Principle of Statistical Analysis 
This study is observational in design and does not involve statistical inference or hypothesis testing. 
The statistical analysis will be performed for this study using SAS® (version 9.4 or higher). 
Descriptive statistics for continuous variables will include the number of observations, mean, 
standard deviation, median, minimum, maximum values, and quartiles (Q1, Q3). Categorical 
variables will be described using frequencies and percentages. Unless otherwise specified, the 
significance level will be set at 5%, and the Confidence Interval (CI) will be set at 95%. 
5.3.3 Baseline Analysis  
The demographic, clinical characteristics, and treatment information of the patients were statistically 
described. The methodology will adhere to standard principles. 
5.3.4 Endpoint analyses 
Descriptive analyses will be conducted on safety and efficacy endpoints. For binary endpoints, counts 
and percentages will be provided, with 95% confidence intervals (CIs) estimated using the exact 
binomial method. Survival endpoints will be assessed using the Kaplan-Meier method to estimate 
survival probabilities and calculate the corresponding 95% CIs, accounting for censored data. 
Continuous endpoints will be summarized with counts, means, medians, standard deviations, 
minimums, maximums, and interquartile ranges, along with their 95% CIs. 
5.4 Stage Analysis 
According to the requirements of NMPA, the collected data will be divided according to the following 
schedule, and the statistics and analysis of clinical data during the corresponding collection period 
will be completed once a year: 
- 
During May 2023 to May 2025  
- 
During June 2025 to May 2026  
- 
During June 2026 to May 2027  

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5.5 Management of Missing and Abnormal Values 
Unless otherwise specified in a specific section, the missing values of baseline and safety data will 
not be filled. 
For the missing efficacy endpoint, the missing values will be filled by the last carry-over method, the 
mean filling method or the multiple imputation method, and the specific filling rules and sensitivity 
analysis will be detailed in the statistical analysis plan. 
5.6 Criteria for Eligible/Ineligible Clinical Study Results 
This is a retrospective, multicenter, observational study, with both safety and efficacy assessments 
being descriptive analysis; therefore, no specific criteria for eligible criteria are set. 
6 Data Management 
6.1 Data Capture 
Electronic Data Capture (EDC) will be used in this study, and clinical study data will be entered into 
eCRF by the investigators or authorized staff at the clinical research institutions. The investigators 
and authorized staff at the clinical research institutions will receive appropriate trainings before the 
initiation of clinical research institutions or data entering and appropriate measures will be adopted 
to protect the security of data. 
The investigators will be responsible for maintaining all source documents and ensure they can be 
monitored by CRAs at each visit. In addition, the investigators shall submit a complete eCRF for 
every patient participating in the study, regardless of the duration of participation. The study number 
and patient number in all supporting documents (e.g., clinical research institution records) submitted 
with eCRF shall be checked carefully and all individual privacy (including the name of patient) shall 
be deleted, or measures shall be taken to make it difficult to identify patients to protect the privacy of 
patients. 
6.2 Data Entering and Modification 
The investigators or designers will be responsible for all entering, correction and modification of data. 
CRAs have no such permissions. All eCRF data will be submitted to the data manager. Any 
modification on data will be recorded by audit tracking, i.e., the reasons for modification, the name 
of the operator, time and date of the modification will be recorded. The role and permission of staff 
who are responsible for entering the data at the clinical research institution will be predetermined. 
CRAs or data management staff will raise queries in EDC for data and the staff at clinical research 
institution will be responsible for handling the queries. EDC system will record the audit tracking of 
queries, including the name of the investigator, time, and date. 
6.3 Database Lock 
The data manager, Principal Investigators (PIs), statistical analysis staff, sponsor and monitoring 
management staff will review the data together, complete the final definition and determination of 
population for analysis, and issue any necessary data queries. Then the database will be locked by 
data manager. 

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In general, locked database shall not be changed. 
6.4 Database Transfer 
The locked database will be transferred to statistical analysis staff for statistical analysis based on 
SAP. 
7 Factors Influencing Study Success and Failure 
7.1 Factors Influencing Study Success 
The indications of the observational device is clear, and the composition and technical index are all 
in accordance with the related national and industry standards. This observational device, with clear 
principles and defined effects, complies with the applicable standards. At present, the devices used in 
this study have been approved and well used in China, and previous clinical studies have confirmed 
that they have good clinical effects and safety. 
Before the start of the study, the clinical data records of each participating Institutions will be 
uniformly reviewed. The data records of the clinical research reference centers are standardized, the 
diagnosis and treatment records are complete, the data are traceable, and the original records are 
complete. 
The study staff participating in the study have sufficient clinical experience and skilled operating 
ability. They also have sufficient patient resources, appropriate study teams, reasonable clinical study 
protocol, unified training for individuals participating in the study and unified recording procedure 
and standard of judgment. The investigators participating in the clinical study will be trained about 
the knowledge of the observational device and operating procedure by technicians of the 
observational device. The investigators shall follow the operating procedures strictly and all 
observations and laboratory results obtained during the clinical study shall be recorded and checked 
carefully to ensure authenticity and reliability of data and to ensure that all conclusions in the clinical 
study are based on source data. 
7.2 Factors Influencing Study Failure 
The non-compliance of study conducts with protocol, incomplete records of observations and 
laboratory test results during the clinical study, or lack of source data supporting may cause the failure 
of this study, but these factors are controllable. 
Each patient participating in the clinical study will be clinically followed up comprehensively. The 
medical records of each patient will be fully monitored to observe the occurrence of complications 
closely and create detailed emergency treatment regimen. Regularly review the patient's medical 
records and record AE information in detail.  
 
In conclusion, the probability of success for this clinical study is high, with a low likelihood of failure. 
However, the potential for failure is correlated with operational risks, patient-related factors, and the 
underlying disease characteristics. 

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8 Quality Control of Clinical Study 
8.1 Investigator Training 
(1) Organize training related to the clinical study of the observational device and participate in the 
clinical study of the medical device within the scope authorized by the principal investigator; (2) 
Fully understand and comply with clinical study protocols and relevant laws and regulations and 
responsibilities related to clinical research of observational device. 
8.2 Data Management 
All data inputs are in Chinese. eCRF shall be completed during or as soon as possible after each visit 
and updated at any time to reflect patient status updates. The data shall be reviewed by the 
investigators to ensure the accuracy and authenticity of all data entered the eCRF. If any evaluation 
is not performed during the trial or any information is unavailable, inapplicable, or unknown, the 
investigators shall record it in the eCRF. The investigators shall electronically sign the verified data. 
8.3 Setting Clinical Events Committee 
The Clinical Events Committee (CEC) is a group of independent experts, who is responsible for 
reviewing and adjudicating adverse events in the study, to ensure that the judgment of adverse events 
in clinical research meets the requirements of the protocol. 
The CEC committee will be composed of independent clinical experts with experience or expertise 
in neurosurgery, and who are not involved in this study. The CEC will provide the definition and 
evaluation criteria of the adverse events in accordance with the CEC charter and this protocol, and 
review and adjudicate the specific events reported.  
9 Ethical Considerations and Informed Consent of Clinical Study 
9.1 Ethical Considerations 
The clinical study must be conducted in accordance with the Declaration of Helsinki, and appropriate 
regulations and laws. The clinical study protocol shall be approved by the ethics committee (EC) of 
the leading site before conducting the study. 
The investigators need to submit the protocol, ICF (If any), and other related documents through the 
management department of the clinical research institution to the EC before the initiation of the study. 
The clinical study will be conducted after approved by the EC. Any modification on the protocol shall 
be approved by the EC before implementation.  
Clinical research institutions for medical devices shall meticulously maintain clinical research records 
and foundational documents in compliance with applicable laws and regulations. 
9.2 Patient Inform Consent Process 
This study is a retrospective study and does not involve the informed consent of patients, and an ICF 
waiver will be applied to the ethics committee. If necessary, an informed consent process will be 
performed as required by the Ethics Committee. 

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10 Adverse Event, Serious Adverse Event 
10.1 Adverse Event 
10.1.1 Definition 
An Adverse Event (AE) is any untoward medical occurrence during the clinical study, whether or not 
related to observational devices (from Good Clinical Practice for Medical Devices).  
 
10.1.2 Determination of Severity 
According to following criteria, severity of AEs can be categorized as mild, moderate, and severe. 
• 
Mild: Transient or mild discomfort; no limitation in activity; no medical intervention/therapy 
required. 
• 
Moderate: Marked limitation in activity, assistance usually required; medical intervention / 
therapy required, possible hospitalization. 
• 
Severe: Extreme limitation in activity, significant assistance required; significant medical 
intervention/therapy required, hospitalization or probable hospice care. 
10.1.3 Determination of Causality Relationship Between AEs and Devices AE 
The causality relationship of AEs with medical devices included "definitely related", "possibly 
related", "likely unrelated" and "definitely unrelated". "Definitely related" and "possibly related" are 
judged as related to the observational device; "likely unrelated" and "definitely unrelated" are judged 
as unrelated to the observational device. The specific judgment criteria are as follows: 
Related to the observational device: (1) There is a reasonable temporal relationship between the AE 
and the observational device; (2) The AE is consistent with the known hazard of the device or may 
be explained by the mechanism of the observational device; (3) The harm is alleviated or disappears 
after the use of the device is stopped; (4) The harm occurs again after the use of the device is resumed; 
(5) The AE cannot be explained by other reasons. It is judged as "definitely related" if all five criteria 
are met and as "possibly related" if two of them are met. 
Unrelated to the observational device: (1) There is no reasonable temporal relationship between the 
AE and the observational device; (2) The AE is a type of event that is unlikely to be caused by the 
observational device; (3) The AE can be explained by concomitant device(s)/drugs, patient disease 
progression, and other therapeutic effects. It is judged as "definitely unrelated" if all three criteria are 
met and as "likely unrelated" if one of them is met. 
The severity of adverse events and their relevance to devices or procedures will be determined 
independently by the CEC Committee in accordance with the unified regulations and principles, 
combined with the collection data (the collection data collection includes patient medical records, 
laboratory tests, and, if necessary, patient's imaging data.) to make a judgment. 
10.1.4 Reporting and Follow-up 
The investigators shall record all AEs that occur during the study, including the name, start and end 

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dates, severity, causality relationship with the device, and outcome of each AE, as well as any action 
taken for each AE. 
The investigators shall provide symptomatic treatment and follow-up for each AE until all symptoms 
disappear or become stable, or otherwise there is another reasonable explanation. 
10.2 Serious Adverse Event 
10.2.1 Definition 
A Serious Adverse Event (SAE) refers to any AE occurrence during a clinical study that causes any 
of the following situations:  
• 
death; or 
• 
serious deterioration in the health of the patient, including: 
- 
a life-threatening illness or injury; or 
- 
a permanent impairment of a body structure or a body function; or 
- 
involved or prolonged inpatient hospitalization; 
- 
medical or surgical intervention to prevent permanent impairment to a body structure or 
a body function; 
• 
fetal distress, fetal death or congenital abnormality or birth defect. 
• 
Other medically significant events. 
All definition above comes from Good Clinical Practice for Medical Devices. 
Note: Planned hospitalization for a pre-existing condition or a procedure required by the clinical 
investigation plan, without serious deterioration in health is not considered an SAE. 
10.2.2 Reporting of SAEs  
For SAEs, investigators shall conduct a comprehensive analysis and assessment of the SAE 
immediately after becoming aware of it, including its severity and relationship to the observational 
device. For suspected SAE related with medical device, investigators shall report to relevant 
personnel. For SAEs lead to death or SAEs lead to serious injury, reports must be submitted within 
reported within the prescribed time frame. 
11 Clinical Event Committee 
The Independent Clinical Event Committee (CEC) will evaluate safety endpoints data and the sponsor 
will appoint a CEC composed of physicians (not investigators) to rule uniformly adjudicate all SAE 
and/or AEs associated with the observational device or observational procedure identified. Only 
CEC's determinations of the collected data (Data collection includes patient medical records, 
laboratory tests, and, if necessary, patients' imaging data) were used for the analysis of safety 
endpoints. 

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12 Protocol Amendments 
If there is any modification to the protocol after EC approval, a “protocol revision statement" or 
revised protocol is required, which shall be signed and confirmed by the sponsor and the coordinating 
investigator and approved by the EC before implementation. 
13 Direct Access to Source Data and Documentation 
Source data refers to the original records of clinical findings, observations, and other activities in a 
medical device clinical study, as well as all information in certified copies, which can be used for the 
reconstruction and evaluation of the clinical study. 
Source documents refer to printed documents, visual files, or electronic files that contain source data. 
The archived materials for this clinical study include: (1) clinical study protocol; (2) electronic case 
report forms (eCRFs); (3) informed consent forms (If any); (4) original medical records of the patients; 
(5) statistical analysis reports; (6) all other materials such as interim reports and final summary reports 
of the clinical study. 
Investigators must carefully complete all study documents, including the confirmation of all 
participated patients (effectively verifying different records, such as eCRFs and original hospital 
records), all original signed informed consent forms of patients (if any), and detailed records in all 
eCRFs. After the study is completed, all clinical study documents shall be submitted to the clinical 
research institution for safekeeping. 
14 Clinical Study Report 
The contents of a clinical study report for a medical device clinical study shall include its general 
information, conduct, statistical analysis methods, study results, reports of AEs and their handling, 
analysis and discussion of study results, clinical study conclusions, ethical description, finding, and 
suggestions for improvement. 
15 Principle of Confidentiality 
The protocol is confidential, which is provided to related medical experts, related personnel such as 
investigators participating in the study, and authorized agencies for related operations such as medical 
institutions undertaking this study, ECs and Contract Research Organization (CRO). Besides 
explaining situation to patients, any content of this protocol shall not become public or be disclosed 
to a third party without a prior written agreement from the sponsor. In addition, if any part of or all 
results of this clinical study are going to be published in external media such as societies and journals, 
written approval from the sponsor shall be obtained. 
The contents of this clinical study and all the attached materials are confidential, exclusive to the 
sponsor, and investigators shall be responsible for the confidentiality. No confidential information, 
including patent application, manufacture process and unpublished data that the sponsor provides 
investigators, shall be disclosed to any third party unless being agreed by the sponsor, and the 
confidentiality obligation remains valid after termination or end of this study. 
Investigators and their staff will collect patients' personal data being used in this study ("study data"), 
including date of birth, gender, identity card, home address, photos and physical or mental health data. 

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All medical records and research materials that can identify patients will be kept confidential within 
the scope of law. However, the management departments of clinical research institutions, ECs, drug 
regulatory authorities, healthcare administrative departments or monitors, auditors are allowed to 
review the personal data o patients participating in the clinical study as necessary to perform their 
work in accordance with the prescribed procedures. All personal information in the study will be 
handled in accordance with the national and local data protection laws. 
Patients have the right to request investigators and sponsor to protect their information and to correct 
any inaccurate information in such data. If patients withdraw informed consent, investigators will no 
longer use or disclose their data, and sponsor may still use the data acquired before withdrawing. 
The study results may be published in medical journals and presented at medical conferences. Patients 
will not be identified in any of these publications. 
16 Responsibilities of All Parties 
16.1 Responsibilities of Sponsor 
(1) The sponsor of a medical device clinical study shall establish a quality management system 
covering the entire process of the clinical study to ensure that the study complies with relevant 
laws and regulations, and to protect the rights and safety of patients. 
 
(2) Prior to the start of the medical device clinical study, the sponsor shall submit the required 
documents to the EC through the Principal Investigator. 
 
(3) The sponsor is responsible for the authenticity and compliance of the medical device clinical 
study. If the sponsor is a foreign entity, it must designate a domestic legal entity in China as its 
agent in accordance with relevant laws and regulations, and the agent shall assist the sponsor in 
fulfilling its responsibilities. 
 
(4) The sponsor shall sign contracts with the medical device clinical research institution and the 
principal investigator, clearly defining the rights and obligations of all parties involved in the 
clinical study. 
 
(5) Before the start of the medical device clinical study, the sponsor is responsible for organizing 
training related to the study, such as on the clinical study protocol, SOPs, and other relevant 
documents.  
 
(6) To ensure the quality of the clinical study, the sponsor may organize audits conducted by auditors 
who are independent of the clinical study and have the necessary training and experience, to 
assess whether the study is being conducted in accordance with the study protocol and relevant 
laws and regulations. 
 

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(7) The sponsor shall ensure that the clinical study is conducted in compliance with the clinical 
study protocol. If the sponsor discovers that the clinical research institution or investigator is not 
adhering to the protocol or relevant laws and regulations, it must promptly identify the issue and 
correct it. If the non-compliance is serious or persists, the sponsor shall terminate the 
participation of the institution and investigator in the study. 
 
(8) The sponsor shall have the necessary facilities and conditions for storing essential clinical study 
documents and shall establish a document management system. The essential documents of the 
medical device clinical study shall be divided into three parts based on the study phase: 
preparatory phase documents, in-progress phase documents, and post-completion or termination 
documents. 
 
(9) The sponsor and the medical device clinical research institution shall ensure the integrity of 
essential clinical study documents during the storage period, preventing intentional or 
unintentional alterations or loss. The sponsor shall retain the essential documents until the 
medical device is no longer in use. 
 
16.2 Responsibilities of Medical Device Clinical Research Institutions 
(1) The medical device clinical research institution shall establish a quality management system that 
covers the entire process of conducting the clinical study, to ensures that the principal 
investigator fulfills their research-related responsibilities, provides proper medical care to 
patients, and ensures the authenticity of the data generated from the study. 
 
(2) Before accepting a medical device clinical study, the clinical research institution shall assess 
relevant resources based on the characteristics of the observational device, ensuring that it has 
the appropriate qualifications, personnel, facilities, and conditions. 
 
(3) The medical device clinical research institution and investigators shall cooperate with 
monitoring and auditing organized by the sponsor, as well as inspections conducted by drug 
regulatory and health administration departments. 
 
(4) The medical device clinical research institution shall properly maintain clinical study records 
and essential documents in accordance with relevant laws and regulations, as well as the contract 
with the sponsor.  
 
(5) The medical device clinical research institution shall have the necessary facilities and conditions 
for storing essential documents and shall establish a management system for these documents. 
The essential documents shall be divided into three parts based on the study phase: preparatory 
phase documents, in-progress phase documents, and post-completion or termination documents. 
 

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(6) The medical device clinical research institution shall ensure the integrity of essential documents 
during the storage period, preventing intentional or unintentional alterations or loss. 
 
16.3 Responsibilities of Investigators 
(1) Develop clinical study protocols, sign clinical study protocols, and be familiar with the use of 
observational device. 
(2) According to the needs of clinical study of medical devices, the principal investigator authorizes 
investigators who have undergone relevant training in clinical study to organize data collection 
and collation; the management and use of observational device; management and use of 
biological samples (as applicable); management of adverse events; recording of clinical study 
data and filling in case report forms, etc. 
(3) When adverse events are found in clinical study, the investigator shall record adverse events that 
occur during the clinical study. 
(4) The investigator shall complete the analysis, judgment, and reporting of serious adverse events 
in accordance with relevant laws and regulations. 
(5) The principal investigator shall report to the ethics committee on the progress of the clinical 
study of medical devices on time. 
17 Miscellaneous Issues to be Clarified 
17.1 Finance and Insurance 
In this clinical study, the sponsor will sign a written agreement with the clinical research institution, 
which will detail the financial arrangements, insurance, and payment methods for the study. The 
specific details are outlined in the agreement signed by the parties involved. 
 
17.2 Agreement on Study Result Publication 
The sponsor and the investigators shall agree on the final clinical study report. Results of this clinical 
study may be published as scientific literature or submitted to authorities. The following provisions 
are made to protect trade secret materials: All information about the observational device (e.g., patent 
application, unpublished manufacture processes, basic scientific data provided to the investigators by 
the sponsor) is considered confidential and proprietary to the sponsor. Investigators are not allowed 
to use it for other purposes without written permission from the sponsor. If the investigator plans to 
reveal or publish study result, the manuscript should be provided to the sponsor 90 days before the 
reveal study result or paper publication, and the sponsor shall review the manuscript and make 
comments within the 90 days, according to generally accepted principle of collaboration in scientific 
fields, investigators shall discuss and agree on publications with the sponsor's personnel prior to 
publication. 

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Investigator Statement 
I agree: 
1. To conduct this clinical study in strict compliance with the Declaration of Helsinki, Good 
Clinical Practice (GCP) (2022), current regulations in China, and the clinical study protocol. 
2. To accurately record all required data in eCRF and complete the clinical study report on time. 
3. To allow the CRAs and auditors authorized or dispatched by the sponsor and regulatory agencies 
to monitor, review, and inspect this clinical study. 
4. To strictly perform the terms of clinical study contracts/agreements executed by all parties. 
I have thoroughly read the clinical study protocol, including the statement above, and I agree with all 
the above. 
 
Opinions of Principal Investigator 
 
 
Signature:： _______________     Date:： _______________ (DDMMMYYYY) 
 
Opinions of Sponsor 
 
(seal) 
Date: _______________ (DDMMMYYYY) 
 
Opinions of Medical Device Clinical research institution 
 
(seal) 
Date: _______________ (DDMMMYYYY) 
 
 

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References 
[1] Neurointerventional Professional Committee for Hemorrhagic Cerebrovascular Diseases 
(Group), NeuroInterventional Professional Committee of Neurosurgery Branch, Chinese 
Medical Doctor Association, Neurointerventional Professional Committee of Interventional 
Physician Branch, Chinese Medical Doctor Association. Chinese Expert Consensus on the 
Treatment of Intracranial Aneurysms with Flow Diverter devices Chinese Journal of 
Neurosurgery 2020. 36(5): 433-445. 
[2] Chalouhi N, Hoh BL, Hasan D. Review of cerebral aneurysm formation, growth, and rupture. 
Stroke. 2013. 44(12): 3613-22. 
[3] Claassen J, Park S. Spontaneous subarachnoid haemorrhage. Lancet. 2022. 400(10355): 846-862. 
[4] Raps EC, Rogers JD, Galetta SL, et al. The clinical spectrum of unruptured intracranial 
aneurysms. Arch Neurol. 1993. 50(3): 265-8. 
[5] Abiaad K R, Aoun R J N, Rahme R J, et al. New generation Hydrogel Endovascular Aneurysm 
Treatment Trial (HEAT): a study protocol for a multicenter randomized controlled trial [J]. 
Neuroradiology, 2018, (4): 1075–1084. 
[6] Wilson J T L, Hareendran A, Grant M, et al. Improving the Assessment of Outcomes in Stroke: 
Use of a Structured Interview to Assign Grades on the Modified Rankin Scale[J]. Stroke, 2002, 
33(9): 2243–2246.