The Use and Reproducibility of Duplex Ultrasound to Provide Indices of Left Common Iliac Vein (CIV) Diameter, to Aid and Improve the Diagnosis of May Thurner Syndrome (MTS) in Patients Presenting With Unexplained Left Leg Swelling
Phase: NA
Conditions: May-Thurner Syndrome
Sponsor: Imperial College London

 
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Template Protocol for non-CTIMPs 
 
 
 
 
The Use and Reproducibility of Duplex Ultrasound to Provide Indices of 
Left Common Iliac Vein Diameter 
 
 
 
Version 1.2, 20/10/2023  
 
 
 
MAIN SPONSOR: Imperial College London  
FUNDERS: N/A 
STUDY COORDINATION CENTRE: N/A  
 
IRAS Project ID: 306125  
REC reference: 23/LO/0271  
 
 
 
Protocol authorised by: 
 
Name & Role 
Date 
Signature 
Megan Coombs, 
Research Office 
26.10.2023 
        M.Coombs 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 
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Study Management Group 
 
Chief Investigator: Professor Alun Davies 
 
 
 
Co-investigators: Sophie Connolly 
 
 
Study Coordination Centre (may not be applicable) 
 
N/A 
 
 
Clinical Queries 
 
Clinical queries should be directed to Sophie Connolly who will direct the query to 
the appropriate person 
 
 
Sponsor 
 
Imperial College London is the main research Sponsor for this study.  For further 
information regarding the sponsorship conditions, please contact the Head of 
Regulatory Compliance at: 
 
 
 
Research Governance and Integrity Team 
Imperial College London and Imperial College Healthcare NHS Trust 
Room 215, Level 2, Medical School Building 
Norfolk Place 
London, W2 1PG 
Tel: 0207 594 1862 
Imperial College - Research Governance and Integrity Team (RGIT) Website 
 
Funder 
 
N/A.  
 
 
 
This protocol describes the proposed study The Use and Reproducibility of Duplex Ultrasound to 
Provide Indices of Left Common Iliac Vein Diameter and provides information about procedures for 
entering participants.  Every care was taken in its drafting, but corrections or amendments may be 
necessary. These will be circulated to investigators in the study.  Problems relating to this study should 
be referred, in the first instance, to the Chief Investigator.  
 

 
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This study will adhere to the principles outlined in the UK Policy Frame Work for Health and Social Care 
Research. It will be conducted in compliance with the protocol, the Data Protection Act and other 
regulatory requirements as appropriate.  
 
Table of Contents                                                             Page No 
1. 
INTRODUCTION 
6 
1.1. 
BACKGROUND 
6 
1.2. 
RATIONALE FOR CURRENT STUDY 
7 
2. 
STUDY OBJECTIVES 
8 
3. 
STUDY DESIGN 
8 
3.1. 
STUDY OUTCOME MEASURES 
11 
4. 
PARTICIPANT ENTRY 
11 
4.1. 
PRE-REGISTRATION EVALUATIONS 
11 
4.2. 
INCLUSION CRITERIA 
11 
4.3. 
EXCLUSION CRITERIA 
11 
4.4. 
WITHDRAWAL CRITERIA 
11 
5. 
ADVERSE EVENTS 
11 
5.1. 
DEFINITIONS 
11 
5.2. 
REPORTING PROCEDURES 
12 
6. 
ASSESSMENT AND FOLLOW-UP 
12 
7. 
STATISTICS AND DATA ANALYSIS 
13 
8. 
REGULATORY ISSUES 
13 
8.1. 
ETHICS APPROVAL 
13 
8.2. 
CONSENT 
13 
8.3. 
CONFIDENTIALITY 
14 
8.4. 
INDEMNITY 
14 
8.5. 
SPONSOR 
14 
8.6. 
FUNDING 
14 
8.7. 
AUDITS 
15 
9. 
STUDY MANAGEMENT 
15 
10. 
PUBLICATION POLICY 
15 
11. 
REFERENCES 
15 
 
 
GLOSSARY OF ABBREVIATIONS 
CIV 
Common iliac vein 
MTS 
May Thurner Syndrome 
DVT 
Deep vein thrombosis 
IVUS 
Intravascular Ultrasound 
CFV 
Common femoral vein 
 
 
 
 
 
 

 
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KEYWORDS 
 
Common Iliac Vein (CIV) 
May-Thurner Syndrome (MTS) 
Duplex Ultrasound 
 
 
 
 
 

 
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STUDY SUMMARY 
 
TITLE The use and reproducibility of duplex ultrasound to provide indices of left 
Common Iliac Vein (CIV) diameter, for improved diagnosis of May Thurner 
Syndrome (MTS) in patients presenting with unexplained left leg swelling. 
DESIGN Feasibility/Pilot Study. 
AIMS To investigate the use and reproducibility of duplex ultrasound to determine 
diameter indices of left CIV compression. 
OUTCOME MEASURES The diameter measurement of the left CIV in adults, and the inter- and intra-
operator variation of the diameter measurement of the left CIV using duplex 
ultrasound. 
POPULATION Adult patients referred to the vascular ultrasound department. 
ELIGIBILITY Patients with or without venous disease, who have not had previous treatment 
for iliac vein disease.  
DURATION 9 months  
 
 
REFERENCE DIAGRAM 
 
[if appropriate] 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 
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1. INTRODUCTION  
 
 
1.1. 
BACKGROUND 
 
May Thurner Syndrome (MTS) is a vascular condition whereby the left common iliac vein 
(CIV) becomes compressed between the right common iliac artery and the spine. This condition is 
often asymptomatic, however MTS can cause severe left lower limb complications such as swelling, 
pain, oedema, reflux, varices, skin changes and deep vein thrombosis (DVT). It is thought that 
approximately 2-3% of lower limb DVT’s are caused by MTS, however there is an almost 56% 
predominance for left sided DVT suggesting this number is underestimated and cases of MTS are 
regularly missed (Peters et al., 2012). DVT can be a serious medical condition and can go on to 
cause pulmonary embolism, a sometimes fatal condition if not identified and treated quickly and 
effectively. 
 
Diagnostic imaging studies such as ultrasonography, venography and intravascular 
ultrasound (IVUS) are used to evaluate the CIV and identify the site and severity of any narrowing that 
is present. Duplex ultrasound is often the first line of imaging as it is risk free, cost effective, and 
accurate at identifying lower limb venous insufficiency. However the location of the iliac veins deep in 
the abdomen has limited its use for identifying specific features of MTS. It is also highly operator 
dependent and the results obtained may be dependent on the experience level of the vascular 
scientist performing the scan. Abdominal ultrasound scans are also always performed with the patient 
lying completely flat, however this does not reflect the haemodynamic changes that occur within the 
venous system when a patient is standing. Indirect measurements can be taken to help indicate if 
there is an iliac vein obstruction, such as interrogation of the common femoral vein (CFV) to assess 
phasicity and reflux. However, these readings can suggest proximal problems but do not differentiate 
between compression and thrombus. 
 
The gold standard for diagnosing MTS is venography, whereby a catheter is inserted into the 
iliac system and changes in pressure gradients are calculated across the region of compression. This 
procedure, however, is invasive, time consuming and exposes patients to radiation and contrast dyes. 
IVUS is also a well-used diagnostic tool for MTS. It is highly sensitive at identifying CIV compression 
and the development of intraluminal “spurs” and neointimal hyperplasia that is associated with MTS. 
IVUS however is also invasive, is unable to provide information related to extravascular lesions and 
there are fewer studies that have looked into the use of IVUS and the benefit to patient outcomes. 
 
Metzger et al. (2016) examined the suitability of using velocity ratios to determine CIV 
stenosis. They used ultrasound to examine 76 patients with a range of chronic venous insufficiency 
symptoms. They took velocity measurements before an area of obstruction and within it, to create a 
venous iliac velocity ratio (VR). All patients were also assessed using IVUS, and diameter and area 
reduction measurements were recorded. Results found that a VR of >2 equated to a significant iliac 
lesion (defined as >50%). The results of this research are consistent with the case study by Oǧuzkurt 
et al. (2007), who found an increase in velocity from 40cm/s to 100cm/s in the left CIV. This would 
equate to a VR of 2.5, and therefore a >50% obstruction on IVUS. The use of velocities to examine 
iliac veins, however, is controversial as peak systolic velocity measurements originated from arteries, 
where a critical stenosis is defined as >75% reduction in the diameter of the artery (Sloves and 
Almeida, 2018). Applying the same method to veins is difficult, as veins differ in shape and size, 
particularly those that are diseased or compressed as they become more elliptical in shape. Also, it is 
venous pressure rather than venous flow that plays the key role in venous stenosis. Additionally, all 
patients in this study were required to fast for 6 hours prior to having the ultrasound scan and were 
administered with dimethicone to aid visualisation of the iliac vessels. This is therefore not an 
accurate representation of the kind of scans that take place on a day to day basis, with few patients 
asked to fast before coming to a hospital appointment and none given medication to aid the process. 
Although in this study the VR was comparable to IVUS, it may not be reproducible in a workplace 
setting. 
Another study used ultrasound to interrogate the CFV as a means of determining a value for 
identifying iliac vein stenosis. Mousa et al. (2016) examined the CFV and saphenofemoral junction in 
36 patients with chronic venous ulcers, to see if reflux in the CFV (described as persistent reverse 

 
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flow for more than 1.0 second demonstrated on the Doppler spectral display) can be used to 
determine iliac vein stenosis greater than 50% (which was quantified using IVUS). They found that 
reflux in the CFV of greater than 2.5 seconds correlated to an iliac vein stenosis of greater than 50% 
(Mousa et al., 2016). This finding may be of great importance for deciding on effective treatment 
strategies for patients with chronic venous ulcers, such as the potential for iliac vein stenting when 
reflux is found to be greater than 2.5 seconds in the ipsilateral CFV. However, these measurements 
may not directly correspond to iliac vein compression and MTS, and further evaluation of these two 
parameters would be needed.    
Similar research by Hui et al. (2020) looked at the use of lower extremity ultrasound as a 
screening tool for detecting iliocaval obstruction. The retrospective study examined images from 132 
patients who had undergone lower extremity venous procedures over a 22 year period. Images from 
CT, MR and conventional venography were compared to the spectral Doppler image taken from the 
CFV on the same patient. The investigators examined phasicity and response to the Valsalva 
manoeuvre as a predictor of iliac vein patency. The study found that overall sensitivity of using 
nonphasic flow or response to Valsalva manoeuvre as an indicator of iliocaval obstruction was poor, 
whereas the specificity was reasonably good. It was suggested from this that positive results are likely 
to indicate a true obstruction in the ipsilateral iliac system, whereas negative results may not be 
reliable and the usefulness of these results may be questionable (Hui et al., 2020). Relating this to 
MTS, interrogation of the flow patterns in the CFV could indicate a complete compression of the CIV, 
but could not be used to indicate the degree of compression or used as a diagnosis tool. Therefore 
further research is required in this area to determine if duplex ultrasound can be used to directly 
image CIV compression, and if it can be used to determine a specific diameter measurement at which 
the CIV is considered compressed or not compressed.  
 
 
1.2. 
RATIONALE FOR CURRENT STUDY 
 
More widespread use of ultrasound for examining the iliac veins would be beneficial as it may avoid 
the need to expose patients to the invasive procedures requiring radiation and contrast agents that are 
necessary for venography and IVUS. Previous studies examining duplex ultrasound and iliac veins, as 
mentioned above, have examined the use of velocity ratios, interrogation of the CFV and examination 
of phasicity but have not investigated using ultrasound to measure the absolute diameter of the CIV. 
There is currently no definitive diameter that the CIV can be considered compressed or not compressed. 
All of the previous studies used symptomatic patients only and so it cannot be assumed that the results 
would correlate in asymptomatic patients. Also, it is known that ultrasound is highly operator dependent 
but none of the previous studies examined the impact of this on measuring the CIV diameter. Therefore, 
further work needs to be carried out to assess the use of ultrasound for imaging the left CIV and aiding 
MTS diagnosis. 
The principle research question is whether duplex ultrasound could be used to image the left CIV 
and investigate diameter ranges that can help in the diagnosis of MTS. The first objective is to use 
duplex ultrasound to image the left CIV in a cohort of patients referred to the vascular ultrasound 
clinic. The second objective is to determine inter- and intra-observer variation of the diameter 
measurement of the left CIV using duplex ultrasound. The hypothesis is that ultrasound can be used 
to image left CIV compression and the measurements obtained during the examination are highly 
reproducible both within an operator and between operators.  
If the results of this research study find that ultrasound can be used to image the left CIV, can define 
‘normal’ diameter ranges and is a reproducible diagnostic tool, then this could reduce the time taken for 
patients presenting with symptoms of MTS to be diagnosed. Ultrasound is a quick and readily available 
imaging tool, and so creating an appropriate scanning protocol will enable regular scanning and 
screening of patients who may have this condition. As well as aiding diagnosis it should also help reduce 
the number of patients with this condition that go on to suffer from further severe complications such as 
DVT. These results should also help identify which patients need to go on to have the more invasive 
tests and rule out patients that do not require them. Iliac vein scanning with ultrasound is not routinely 
performed in all vascular departments across the country, with many only taking indirect measurements 
from the CFV’s. If a benefit is found to doing this scan then it could be introduced to many more/all 
departments, benefiting many more patients. 

 
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2. STUDY OBJECTIVES 
 
 
The primary objective of this study is to investigate diameter variation of the left CIV based on posture 
in adults referred to the vascular ultrasound department, using duplex ultrasound. 
The secondary objective of this study is to determine inter- and intra-observer variation of the 
diameter measurement of the left CIV using duplex ultrasound, in adults referred to the vascular 
ultrasound department.   
 
3. STUDY DESIGN 
 
 
The study will be a feasibility/pilot study lasting approximately six months, recruiting 40 
patients from the vascular ultrasound department at Imperial College Healthcare NHS Trust. 20 
patients will be symptomatic for lower limb venous disease and 20 patients will be asymptomatic. The 
following outlines the timeline of events for the patients recruited onto the study.  
 
OUTPATIENT APPOINTMENT 
 
At their outpatient appointment patients who may be eligible to take part in the study will be identified 
and approached. Patient notes and GP referral letters will be read prior to seeing the patient in the 
outpatient appointment, to identify suitable participants. Suitable participants will be those that will be 
requiring a vascular ultrasound scan in the vascular ultrasound department. The study will be 
explained and if the patient gives verbal consent to receiving study information material, then this will 
be given to the patient for consideration. They will be told that formal consent will be taken at their 
scan appointment if they agree to partake in the study and that if they choose not to partake this will 
not affect their usual clinical care. Participants will be given up to six weeks to decide if they would like 
to take part. 
 
TELEPHONE CALL 
 
Patients will be contacted two weeks after their outpatient appointment to enquire as to whether they 
would like to take part in the study. Those that decline will have their scan request form passed on to 
the department receptionist for booking in the usual way. Those that would like to take part in the 
study will have a date and time arranged to come to the department to have their scan as part of the 
study, followed by the scan requested by the clinical team. The study scan and the routine scan will 
be made on the same day to avoid the patient having to come to the hospital multiple times. Some 
patients form the symptomatic group may have been referred for this type of scan.  
 
ULTRASOUND SCAN APPOINTMENT 
 
Order of events at the scan appointment will be as follows; 
 
- Eligibility check and formal consent - 5 minutes 
- Recording of demographic details and medical history - 5 minutes 
- The patient will have their routine scan performed as requested by the referring clinician - Between 
30 and 90 minutes, dependent on the scan type requested. 
- A clinical vascular scientist will perform the study ultrasound scan and take three readings of the left 
CIV with the patient lying flat and three readings of the left CIV with the patient at a 45 degree angle 
on a tilted examination couch - 10 minutes 
- Two further clinical vascular scientists will perform the same study scan and take the same readings 
- 20 minutes 
- Patient will be thanked for their time and a routine follow up appointment will be made with the 
referring clinician. 
 

 
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The below flow chart illustrates this order of procedures: 
 
Prior to the ultrasound scan appointment: 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
GP referrals read prior to 
outpatient appointment, and 
potential participants 
identified. 
Patient approached by chief 
investigator at outpatient 
appointment. Study explained 
and patient information sheet 
provided to the patient.  
Telephone call to patient two 
weeks later to enquire as to 
whether they would like to 
participate in the study.  
Patient declines. 
Routine scan 
request from 
outpatient 
appointment passed 
to department 
receptionist for 
booking, and clinical 
care continues as 
usual. 
Patient accepts. Date and time 
arranged for scan (both scans 
will be performed at the same 
time – the iliac scan as part of 
the study, and routine scan 
requested by clinical team at 
outpatient appointment). 

 
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During the ultrasound scan appointment: 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Eligibility check and formal consent taken 
from the participant. Demographic details 
and medical history recorded. 
A clinical vascular scientist will use an ultrasound machine to take 
three readings of the left common iliac vein diameter with the patient 
lying supine, and three readings of the left common iliac vein 
diameter with the patient lying at a 45 degree angle on a tilted couch. 
A second clinical vascular scientist will use an ultrasound machine to 
take three readings of the left common iliac vein diameter with the 
patient lying supine, and three readings of the left common iliac vein 
diameter with the patient lying at a 45 degree angle on a tilted couch. 
A third clinical vascular scientist will use an ultrasound machine to 
take three readings of the left common iliac vein diameter with the 
patient lying supine, and three readings of the left common iliac vein 
diameter with the patient lying at a 45 degree angle on a tilted couch. 
The participant will be thanked for their time 
and a routine follow up appointment will be 
made with the referring clinician. 
The participant will have their 
routine scan performed as 
requested by the referring clinician. 

 
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3.1. 
STUDY OUTCOME MEASURES 
 
 
The primary outcome measure is the diameter variation ranges of the left CIV in adults referred to 
the vascular ultrasound department.  
The secondary outcome measure is the inter- and intra-operator variation of the diameter 
measurement of the left CIV using duplex ultrasound, in adult patients referred to the vascular 
ultrasound department.  
 
4. PARTICIPANT ENTRY 
 
4.1. 
PRE-REGISTRATION EVALUATIONS  
 
 
Patients notes, GP referrals and current scan request forms will be examined to determine 
that the patient does require a vascular ultrasound scan. 
 
4.2. 
INCLUSION CRITERIA  
 
 
Patients will only be included if: 
• 
They have the capacity to consent. 
• 
They are required to have a vascular ultrasound scan in the vascular ultrasound 
department at ICHT. 
 THEY ARE 18 YEARS OF AGE OR OLDER AT THE START OF THE STUDY. 
4.3. 
EXCLUSION CRITERIA 
 
 
Patients will be excluded if: 
• 
They do not have capacity to consent. 
• 
They do not require a vascular ultrasound scan as part of their routine care. 
• 
They are under 18 years of age at the start of the study. 
• 
They are pregnant. 
• 
They have had previous interventions/treatment for iliac vein disease. 
• 
They have had a previous diagnosis of iliac vein thrombus. 
 
4.4. 
WITHDRAWAL CRITERIA  
 
A participant may withdraw at any time by notifying the researcher in person or in written form. If a 
patient withdraws from the study, any data collected up until that time will remain on file and will be 
included in the final study analysis.  
 
 
5. ADVERSE EVENTS  
 
5.1. 
DEFINITIONS  
Adverse Event (AE): any untoward medical occurrence in a patient or clinical study subject.   
 
Serious Adverse Event (SAE): any untoward medical occurrence or effect that: 
• 
Results in death 
• 
Is life-threatening – refers to an event in which the subject was at risk of death 
at the time of the event; it does not refer to an event which hypothetically might 
have caused death if it were more severe 
 

 
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• 
Requires 
hospitalisation, 
or 
prolongation 
of 
existing 
inpatients’ 
hospitalisation 
• 
Results in persistent or significant disability or incapacity 
• 
Is a congenital anomaly or birth defect 
 
Medical judgement should be exercised in deciding whether an AE is serious in other 
situations.  Important AEs that are not immediately life-threatening or do not result in death or 
hospitalisation but may jeopardise the subject or may require intervention to prevent one of 
the other outcomes listed in the definition above, should also be considered serious. 
 
5.2. 
REPORTING PROCEDURES  
All adverse events should be reported.  Depending on the nature of the event the reporting 
procedures below should be followed.  Any questions concerning adverse event reporting 
should be directed to the Chief Investigator in the first instance.   
 
5.3.1 Non serious AEs 
All such events, whether expected or not, should be recorded  
 
5.3.2 Serious AEs 
An SAE form should be completed and emailed to the Chief Investigator within 24 hours.  
However, relapse and death due to a pre-existing, non-vascular related condition, and 
hospitalisations for elective treatment of a pre-existing condition do not need reporting as 
SAEs. 
 
All SAEs should be reported to the London – Riverside Research Ethics Committee where in 
the opinion of the Chief Investigator, the event was: 
• 
‘related’, ie resulted from the administration of any of the research procedures; 
and 
• 
‘unexpected’, ie an event that is not listed in the protocol as an expected 
occurrence 
 
Reports of related and unexpected SAEs should be submitted within 15 days of the Chief 
Investigator becoming aware of the event, using the NRES SAE form for non-IMP studies.  
The Chief Investigator must also notify the Sponsor of all related and unexpected SAEs. 
 
Local investigators should report any SAEs as required by their Local Research Ethics 
Committee, Sponsor and/or Research & Development Office. 
 
Contact details for reporting SAEs 
RGIT@imperial.ac.uk 
CI email a.h.davies@imperial.ac.uk (and contact details below) 
Fax: N/A, attention N/A  
Please send SAE forms to: Professor Alun Davies 
Tel: 02033117320 (Mon to Fri 09.00 – 17.00) 
 
6. ASSESSMENT AND FOLLOW-UP  
 
This study is in addition to any NHS treatment the participants may be having, 
so there will be no assessment or follow-up required. In the event of discovering an 

 
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incidental finding, the participants’ referring clinician will be informed via a telephone 
call or email from the researcher (dependant on urgency of findings e.g. the referring 
clinician or on-call vascular registrar will immediately be called if there is an 
incidental finding of acute thrombus in the iliac veins). The study will end when the 
last participant recruited on to the study has attended their ultrasound scan 
appointment.   
 
 
7. STATISTICS AND DATA ANALYSIS 
 
The sample size has been calculated using a sample size calculator assuming a 
prevalence of 2%, confidence level of 95% and margin of error of 5%. This 
calculation gives a sample size of 31. This sample size is in line with a previous 
study by Mousa et al. (2016) which had a sample size of 36. 
 
A one-way ancova test will be performed to assess the difference in iliac vein 
diameter between the two groups. An intraclass correlation coefficient will be used to 
measure intra- and inter-observer reliability. Support will be provided from the 
Imperial Statistics Services during the analysis phase. 
 
Statistics and data analysis aspects of the study have been reviewed by May 
Azzawi, the academic supervisor at Manchester Metropolitan University. 
 
Data and all appropriate documentation will be stored for a minimum of 10 years 
after the completion of the study, including the follow-up period.   
 
 
8. REGULATORY ISSUES  
 
8.1. 
ETHICS APPROVAL  
The Study Coordination Centre has obtained approval from the London - Riverside 
Research Ethics Committee (REC) and Health Research Authority (HRA). The study 
must also receive confirmation of capacity and capability from each participating NHS 
Trust before accepting participants into the study or any research activity is carried 
out. The study will be conducted in accordance with the recommendations for 
physicians involved in research on human subjects adopted by the 18th World Medical 
Assembly, Helsinki 1964 and later revisions. 
 
8.2. 
CONSENT   
Consent to enter the study must be sought from each participant only after a full 
explanation has been given, an information leaflet offered and time allowed for 
consideration.  Signed participant consent should be obtained.  The right of the 
participant to refuse to participate without giving reasons must be respected.  After the 
participant has entered the study the clinician remains free to give alternative 
treatment to that specified in the protocol at any stage if he/she feels it is in the 
participant’s best interest, but the reasons for doing so should be recorded.  In these 
cases the participants remain within the study for the purposes of follow-up and data 

 
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analysis.  All participants are free to withdraw at any time from the protocol treatment 
without giving reasons and without prejudicing further treatment. 
 
8.3. 
CONFIDENTIALITY  
 
The Chief Investigator will preserve the confidentiality of participants taking part in the 
study and is registered under the Data Protection Act. 
 
Data will be  anonymised. 
 
Personal data will be stored on NHS computers and will be password protected. 
Manual files e.g. consent forms will be stored in locked cabinets at the NHS site. All 
data will be collected according to the Data Protection Act 2018 and in line with 
general data protection regulation (GDPR). 
 
Personal data will be anonymised by converting to a study code. Subject study data 
will be first collected on a paper case report form. This original source data will then 
be transcribed electronically onto a trial database, REDcap. The database is stored 
on a private network protected by a firewall. Access to the database is restricted to 
trial staff by login and password. 
 
All personal identifying data will be kept electronically on NHS computers and in 
paper format stored in NHS premises with secure offices only accessible by 
authorised personnel.  
 
Paper copies of consent forms will be kept in confidential files in a lockable office 
only accessible by authorised personnel. 
 
Data and all appropriate documentation will be stored for a minimum of 10 years. 
 
 
 
8.4. 
INDEMNITY 
Imperial College London holds negligent harm and non-negligent harm insurance 
policies which apply to this study. 
 
8.5. 
SPONSOR  
Imperial College London will act as the main Sponsor for this study.  Delegated 
responsibilities will be assigned to the NHS trusts taking part in this study.   
 
8.6. 
FUNDING  
There is no official funder for this study. Participants will not receive any payments, 
reimbursement of expenses or any other benefits or incentives for taking part in this 
research. Individual researchers will not receive any personal payment over and 
above normal salary, or any other benefits or incentives for taking part in this 
research.  

 
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8.7. 
AUDITS   
The study may be subject to audit by Imperial College London under their remit as 
sponsor and other regulatory bodies to ensure adherence to GCP and the UK Policy 
Frame Work for Health and Social Care Research.  
 
 
9. STUDY MANAGEMENT  
 
The day-to-day management of the study will be co-ordinated through the Principal 
Investigator.  
 
 
10. PUBLICATION POLICY  
 
The results will be included in the final clinical doctorate thesis. The results will be 
published in peer reviewed journals, as an internal report, conference papers and 
research presentations. The anonymity of the participants will be ensured when 
publishing. Participants will receive a newsletter outlining the findings on completion 
of the study. 
 
 
11. REFERENCES  
 
Hui, J. Z., Goldman, R. E., Mabud, T. S., Arendt, V. A., Kuo, W. T. and Hofmann, L. v. (2020) 
“Diagnostic performance of lower extremity Doppler ultrasound in detecting iliocaval obstruction.” 
Journal of Vascular Surgery: Venous and Lymphatic Disorders. Elsevier Inc., 8(5) pp. 821–830. 
 
Metzger, P. B., Rossi, F. H., Kambara, A. M., Izukawa, N. M., Saleh, M. H., Pinto, I. M. F., Amorim, J. 
E. and Thorpe, P. E. (2016) “Criteria for detecting significant chronic iliac venous obstructions with 
duplex ultrasound.” Journal of Vascular Surgery: Venous and Lymphatic Disorders. Society for 
Vascular Surgery, 4(1) pp. 18–27. 
 
Mousa, A. Y., Broce, M., Yacoub, M., Hanna, P., Baskharoun, M., Stone, P. A., Bates, M. C. and 
Aburahma, A. F. (2016) “Validation of venous duplex ultrasound imaging in determining iliac vein 
stenosis after standard treatment of active chronic venous ulcers Presented at the Twenty-ninth 
Annual Meeting of the Eastern Vascular Society, Baltimore, MD September 24-26, 2015.” Journal of 
Vascular Surgery: Venous and Lymphatic Disorders. Society for Vascular Surgery, 4(3) pp. 307–312. 
 
Oǧuzkurt, L., Özkan, U., Tercan, F. and Koç, Z. (2007) “Ultrasonographic diagnosis of iliac vein 
compression (May-Thurner) syndrome.” Diagnostic and Interventional Radiology, 13(3) pp. 152–155. 
 
Peters, M., Syed, R. K., Katz, M., Moscona, J., Press, C., Nijjar, V., Bisharat, M. and Baldwin, D. 
(2012) “May-Thurner Syndrome: A Not So Uncommon Cause of a Common Condition.” Baylor 
University Medical Center Proceedings, 25(3) pp. 231–233. 
 
Sloves, J. and Almeida, J. I. (2018) “Venous duplex ultrasound protocol for iliocaval disease.” Journal 
of Vascular Surgery: Venous and Lymphatic Disorders. Elsevier Inc., 6(6) pp. 748–757. 
 

 
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APPENDICES 
 
PIS and Consent form, recruitment poster and letter to GP attached separately.