A Risk-adjusted and Anatomically Stratified Cohort Comparison Study of Open Surgery, Endovascular Techniques and Medical Management for Juxtarenal Aortic Aneurysms: The UK COMplex AneurySm Study


A Risk-adjusted and Anatomically Stratified Cohort Comparison Study of Open Surgery, Endovascular Techniques and Medical Management for Juxtarenal Aortic Aneurysms: The UK COMplex AneurySm Study
Funding NIHR HTA
Portfolio Surgical
Interventions Surgery
Randomised False
Status Recruiting
Start Date 09-Oct-2018

UK-COMPASS is a research study looking at the treatment of juxtarenal aortic aneurysms.

What is the study about?

Abdominal aortic aneurysm is a common condition where the aorta, which is the main artery that begins at the heart and travels down the torso, begins to bulge and expand at a portion just below the chest, above the level of the navel. In the usual course of events, the bulge expands slowly over many years and can eventually burst. This results in major internal blood loss often resulting in death and when an emergency lifesaving operation is possible, they have high failure rate. Although the risk of aneurysm rupture is generally low, it starts to increase if the aneurysm exceeds a certain size. A planned operation can be performed to repair the bulging section of aorta to prevent a burst aneurysm. However, not all abdominal aortic aneurysms are equal and technical aspects of aneurysm repair depends upon their location in relation to important branch arteries of the aorta.

Over a quarter of aneurysms are classed as juxtarenal aneurysms because they are too close to the arterial branches supplying blood to the kidneys. These aneurysms require more extensive and more complex operations. There are different ways of managing such complex aneurysms and doctors are unsure which method is better. The open repair method is the tried and trusted method, known to be durable and lasts for the rest of most patients’ lives. However, it is quite a serious operation which generally involves a longer stay in hospital and a higher chance of dying within 30 days of the operation when compared to alternative methods called endovascular techniques, of which Fenestrated Endovascular Aneurysm Repair (fEVAR) is the most established method. In a number of patients with juxtarenal aneurysms, doctors are judiciously using standard endovascular repair (Offlabel EVAR), a less complex technique that is originally intended for use in less complex aneurysms.

Endovascular methods are less of a strain on the patient’s body which results in a shorter recovery time and a better chance of surviving the operation. The downside of this is that it is more common for there to be problems following endovascular repairs that may require further small procedures to correct them. In some cases, patients are not considered fit enough for the open repair operation as it may be too much of a strain on their body and always requires a general anaesthetic. For these patients, doctors find fEVAR or off-label EVAR quite attractive. In a proportion of patients, no operation may be considered to be in their best interest.

This study is proposed to examine how these different treatment methods compare in terms of clinical benefit and utilisation of valuable NHS resources. We would also like to establish if particular patient features will give better results with one type of operation than the other.

For the first part of this cohort study (or the ‘Routinely Collected Dataset’) we intend to include all patients undergoing juxtarenal aneurysm treatment in England during a period of 2 years (between November 2017 and October 2019) and collect 2-year follow-up. We will also include a retrospectively identified cohort of 300 medically managed/operation deferred patients or patients whose planned operations were delayed due to Covid-related disruption in this data set.

In the second part of this cohort study (or the ‘Quality of Life Study’) we will recruit 1100 patients from participating sites across England. These patients will consist of 800 patients who have an operation to manage their aneurysm and 300 patients whose aneurysm will be medically managed. These patients will be recruited between October 2018 and December 2021. These patients will
complete questionnaires/diaries about their health at scheduled intervals for a minimum of 2 years up to a maximum of 5 years.

The Quality of Life Study has now completed recruitment and data collection.



Who is running the study?

Liverpool University Hospitals NHS Trust is the Sponsor of this study and is responsible for managing it. They are based in United Kingdom. They have asked that the day to day running of the study is carried out by a team based at the Liverpool Clinical Trials Centre (LCTC, part of the University of Liverpool), and health economics researchers from the University of Liverpool (the central study team).

The study has been reviewed by the Confidentiality Advisory Group (CAG) and received Section 251 approval, the Health Research Authority (HRA) and a National Research Ethics Service Research Ethics Committee (REC) to make sure that the study is scientifically and ethically acceptable. 

This study is funded by the National Institute for Health Research (NIHR) Health Technology Assessment (HTA) Programme. 

The trial is also registered on the NIHR Portfolio and is eligible for Clinical Research Network (CRN) support (CPMS ref: 3635).



How will patient information be collected and handled

Liverpool University Hospitals NHS Foundation Trust and the University of Liverpool are the Data Controllers for this study and will use information from patients and their medical records for this research project.

This information will include:

  • Initials
  • NHS number
  • Name
  • Contact details
  • Date of birth (DOB)
  • Medical data
  • CT scan images

This information will be used to do the research and for checking patient records to make sure that the research is being conducted properly.

Individuals from the University of Liverpool, the LCTC, Liverpool University Hospitals NHS Trust and regulatory organisations may look at patient medical and research records to check the accuracy of the research study and ensure it is being conducted properly.

People who do not need to know who the patients are will not be able to see their names or contact details. Their data will have a code number instead.




Routinely Collected Data Set:

For the first cohort (consisting of all patients, in England, undergoing AAA surgery between November 2017 and October 2019), the patients have been identified using Hospital Episode Statistic (HES) Data supplied by NHS Digital to the CORE Lab team at The Royal Liverpool Hospital (a part of Liverpool University Hospitals NHS Foundation Trust). The CORE Lab at the Royal Liverpool Hospital then use identifiable information (NHS number, name, date of birth) from this dataset to request CT-scan images from NHS-PACS. The scan images will be pseudonymised and reviewed by vascular clinicians at The Royal Liverpool Hospital who (based on anatomy) will then determine whether the patient’s data set should be included in the study. If the data is included in the study we then request data from the National Vascular Registry in the form of the patient’s aneurysm score. We will also further extract HES data at 6-month periods for a maximum of 2 years to determine patient outcomes. See diagram below.

The 300 medically managed/Covid delayed patients included in this dataset will be identified by participating NHS Hospitals.

This part of the study did not approach patients for consent to access their data – instead, the study received Section 251 approval via Confidentiality Advisory Group (CAG).


Quality of Life Study:

Patients will complete quality of life questionnaires at scheduled intervals during their time in the study. The questionnaire data will be sent from the patient’s hospital to the LCTC at baseline, subsequent questionnaire data will be sent from the patient to the LCTC. This pseudonymised data will also be viewed by the Health Economics team at University of Liverpool, who will analyse this data.

These patients are asked to agree to disclose their identifiable information with the study team to allow them to contact them to send out questionnaires, access data essential to the study in the form of CT-scans, investigation results and details about their medical history. This information is only shared between the following stakeholders:

1)      the patient’s treating hospital

2)      The Royal Liverpool University Hospital (PACS department and CORE Lab department for retrieval and measurement of CT scans) – a part of Liverpool University Hospitals NHS Foundation Trust

3)      The Liverpool Clinical Trials Centre at the University of Liverpool

4)      The Health Economics team at the University of Liverpool

Additionally, information regarding patient health from a central NHS database (Hospital Episode Statistics Database, NHS Digital) will be sought and shared with the above stakeholders and members of the trial team.


Patient choices for how information is used

Patients can stop being part of the study at any time, without giving a reason, but we will keep information about them that we already have acquired.

If a patient chooses to stop taking part in the study with regards to filling out Quality of Life forms, we would like to continue collecting information about their health from central NHS records and their hospital. If the patient does not want this to happen, they can tell us and we will stop this aspect of their participation as well.

We need to manage patient records in specific ways for the research to be reliable. This means that we won’t be able to let participants see or change the data we hold about them.

Once  the study is completed, the data will be kept for a maximum of 15 years, so we can check the results. The reports will be written in a way that means it will not be possible to identify anyone who has contributed data to the study.


Information sharing

When participants agree to take part in a research study, the information about their health and care may be beneficial to researchers running other research studies in this organisation and in other organisations. These organisations may be universities, NHS organisations or companies involved in health and care research in this country or abroad. This information will only be used by organisations and researchers to conduct research in accordance with the UK Policy Framework for Health and Social Care Research, or equivalent standards.

If a participant agrees to take part in the Quality of Life cohort of this study, they will have the option to take part in future research using the data saved from this study.


Where can I find out more about how information is used?

You can find out more about how we use information:



What if there is a problem?

If you have a concern about any aspect of this study, you should contact


  • N/A