Changes

May 2024 — minor update. Changed information regarding NHS England who are now responsible for the screening programme. 

Update

Goals

To support primary healthcare professionals to:

• Inform eligible people about the abdominal aortic aneurysm (AAA) screening programme. 
• Encourage eligible people to attend the AAA screening appointment. 
• Provide information and advice to men found to have an AAA at the screening appointment. 
• Manage men found to have an AAA at the screening appointment appropriately. 

Outcome measures

No outcome measures were found during the review of this topic.

Audit criteria

No audit criteria were found during the review of this topic.

QOF indicators

No QOF indicators were found during the review of this topic.

NICE quality standards

No NICE quality standards were found during the review of this topic.

QIPP — Options for local implementation

No QIPP indicators were found during the review of this topic.

What is it?

• An abdominal aortic aneurysm (AAA) is a permanent pathological dilation of the abdominal aorta with a diameter over 1.5 times the expected anteroposterior diameter of that segment given the person's sex and body size [BMJ, 2021]. 
• Normally the diameter of the abdominal aorta ranges from 1.2–2.4 cm [UKNSC, 2016].
• The threshold for diagnosis of AAA is an abdominal aortic diameter of 3.0 cm or greater [BMJ, 2021; UKHSA, 2021b].
  • More than 90% of AAAs originate below the renal arteries [BMJ, 2021].
• An AAA usually causes no symptoms, but if it ruptures, it is usually fatal [UKNSC, 2016]. 

How common is it?

• The UK prevalence in the NHS abdominal aortic aneurysm (AAA) screening programme is 1.34% — around 1 in 70 men aged 65 years in England has an AAA.
• In men screened for AAA: 
  • 985 in 1000 will have no aneurysm.
  • 14 in 1000 will have a small or medium aneurysm.
  • 1 in 1000 will have a large aneurysm. 
• There are around 3000 deaths each year in men aged 65 years and over in England and Wales from a ruptured AAA.
• Deaths from ruptured AAA account for 1.7% of all deaths in men aged 65 years and over.

[UKHSA, 2019; BMJ, 2021]

What are the risk factors for abdominal aortic aneurysm?

Risk factors for abdominal aortic aneurysm (AAA) include: 

• Male sex and increasing age — 2 in 3 deaths from ruptured AAA occur in men aged over 65 years.
  • AAA is six times more common in men than women.
• Smoking — each year of smoking increases the relative risk by 4%.
• Hypertension. 
• Positive family history.
  • In a large population-based study the risk of AAA associated with a positive family history was approximately double that compared with a person with no family history. 
  • A Swedish twin registry study found that the twin of a monozygotic twin with AAA had around a 70 times greater risk of AAA compared to a twin without AAA.
• Diabetes mellitus.
• Chronic obstructive pulmonary disease. 

[UKNSC, 2016; UKHSA, 2019; BMJ, 2021]

Who is eligible for routine abdominal aortic aneurysm screening?

• Abdominal aortic aneurysm (AAA) screening is offered to all men the year they become 65 years old.
• Screening is not routinely offered to groups where there is a smaller risk of AAA, including: 
  • Men aged under 65 years.
  • Women.
  • People who have already been treated for AAA.  
• Men can ask for their information to be removed from the AAA screening IT system if they do not wish to take up the offer of screening. 
  • Contact details for local programmes can be found on the NHS website.
• Trans women and non-binary people assigned male at birth who are registered with a GP as: 
  • Female — are not routinely invited for AAA screening but can request screening.
  • Male — are invited for AAA screening.
• Note: any trans woman or non-binary person assigned male at birth will have the same AAA risk as a man and should consider accessing screening.
• Trans men and non-binary people assigned female at birth who are registered with a GP as: 
  • Female — are not invited for AAA screening.
  • Male — are invited for AAA screening but do not have a high risk of AAA.
• Note: trans men and non-binary people assigned female at birth do not have the same risk of AAA as people assigned male at birth.

[UKHSA, 2021c; UKHSA, 2021b; NHS England, 2023] 

How is abdominal aortic aneurysm screening coordinated and managed?

• The NHS abdominal aortic aneurysm (AAA) screening programme is coordinated and led nationally by NHS England. Screening services are delivered locally in line with national quality standards and protocols. 
  • There are 38 local screening services covering the whole of England which coordinate screening and organise invitation letters, screening and surveillance clinics, results letters and referrals to the appropriate vascular network.
  • GPs are informed when men from their practice have been screened and the outcomes of the screening test.
• Men receive a postal invite for a screening appointment when they are aged 64 or 65 — this is usually 3 to 6 weeks in advance of the appointment. 
  • If they do not attend for the appointment they are reinvited for screening. 
  • If they do not attend the second appointment no further invite is sent. 
• Men who have not received an invitation should contact their local AAA screening service to make an appointment. 
  • Details can be found on the NHS website. 

[UKHSA, 2019; UKHSA, 2021b]

What is the abdominal aortic aneurysm screening test?

• The abdominal aortic aneurysm (AAA) screening test involves an abdominal ultrasound scan to detect any bulging or swelling of the aorta.   
  • If the aorta cannot be visualised a repeat scan is arranged.
  • If a repeat scan is not arranged medical imaging may be requested. 
• Possible results are: 
  • No aneurysm found (less than 3.0 cm) — no further scans are required. 
  • Small AAA (3.0 cm to 4.4 cm) — the person is placed under surveillance and a repeat scan offered in 12 months. 
  • Medium AAA (4.5 cm to 5.4 cm) — the person is placed under surveillance and a repeat scan offered in 3 months. 
  • Large AAA (5.5 cm or larger) — the person is referred to a vascular surgeon.
• The screening test takes around 10 to 15 minutes and the results are provided directly to the person at the appointment. 
  • If an aneurysm is found they also receive the result by mail. 
  • If a small or medium aneurysm is found the person's GP is notified by letter.
  • If a large aneurysm is found the person's GP is informed by phone call or fax, and then by letter. 

[UKHSA, 2019; UKHSA, 2021a; UKHSA, 2021b] 

What are the benefits and harms of abdominal aortic aneurysm screening?

• Screening is quick, safe, inexpensive and well-tolerated [UKNSC, 2016].
• Early detection of abdominal aortic aneurysm (AAA) reduces the risk of death from ruptured AAA [UKNSC, 2016].
  • The mortality rate of AAA repair is significantly lower when performed electively than in an emergency. 
  • Up to 80% of people with ruptured AAA do not survive. 
• Possible harms of AAA screening may include:
  • Surgical complications for men who undergo preventative surgery (for example stroke, myocardial infarction) [Damhus, 2021].
  • Overdiagnosis and unnecessary treatment (with an associated increased risk of morbidity and mortality) [Johansson, 2016]. 
  • Negative psychological consequences of AAA diagnosis — for example, anxiety [Damhus, 2021].  

Scenario: AAA screening

From age 16 years onwards.

Search strategy

Scope of search

A literature search was conducted for guidelines, systematic reviews and randomized controlled trials on primary care management of abdominal aortic aneurysm screening. 

Search dates

Unrestricted - March 2023

Key search terms

Various combinations of searches were carried out. The terms listed below are the core search terms that were used for Medline.

• AAA screening
• Abdominal aortic aneurysm screening programme

Sources of guidelines

• National Institute for Health and Care Excellence (NICE)
• Scottish Intercollegiate Guidelines Network (SIGN)
• Royal College of Physicians
• Royal College of General Practitioners
• Royal College of Nursing
• NICE Evidence
• Health Protection Agency
• World Health Organization
• National Guidelines Clearinghouse
• Guidelines International Network
• TRIP database
• GAIN
• NHS Scotland National Patient Pathways
• New Zealand Guidelines Group
• Agency for Healthcare Research and Quality
• Institute for Clinical Systems Improvement
• National Health and Medical Research Council (Australia)
• Royal Australian College of General Practitioners
• British Columbia Medical Association
• Canadian Medical Association
• Alberta Medical Association
• University of Michigan Medical School
• Michigan Quality Improvement Consortium
• Singapore Ministry of Health
• National Resource for Infection Control
• Patient UK Guideline links
• UK Ambulance Service Clinical Practice Guidelines
• RefHELP NHS Lothian Referral Guidelines
• Medline (with guideline filter)
• Driver and Vehicle Licensing Agency
• NHS Health at Work(occupational health practice)

Sources of systematic reviews and meta-analyses

• The Cochrane Library:
  • Systematic reviews
  • Protocols
  • Database of Abstracts of Reviews of Effects
• Medline (with systematic review filter)
• EMBASE (with systematic review filter)

Sources of health technology assessments and economic appraisals

• NIHR Health Technology Assessment programme
• The Cochrane Library:
  • NHS Economic Evaluations
  • Health Technology Assessments
• Canadian Agency for Drugs and Technologies in Health
• International Network of Agencies for Health Technology Assessment

Sources of randomized controlled trials

• The Cochrane Library:
  • Central Register of Controlled Trials
• Medline (with randomized controlled trial filter)
• EMBASE (with randomized controlled trial filter)

Sources of evidence based reviews and evidence summaries

• Bandolier
• Drug & amp; Therapeutics Bulletin
• TRIP database
• Central Services Agency COMPASS Therapeutic Notes

Sources of national policy

• Department of Health
• Health Management Information Consortium(HMIC)

Patient experiences

• Healthtalkonline
• BMJ - Patient Journeys
• Patient.co.uk - Patient Support Groups

Sources of medicines information

The following sources are used by CKS pharmacists and are not necessarily searched by CKS information specialists for all topics. Some of these resources are not freely available and require subscriptions to access content.

• British National Formulary(BNF)
• electronic Medicines Compendium(eMC)
• European Medicines Agency(EMEA)
• LactMed
• Medicines and Healthcare products Regulatory Agency(MHRA)
• REPROTOX
• Scottish Medicines Consortium
• Stockley's Drug Interactions
• TERIS
• TOXBASE
• Micromedex
• UK Medicines Information

Stakeholder engagement

Our policy

The external review process is an essential part of CKS topic development. Consultation with a wide range of stakeholders provides quality assurance of the topic in terms of:

• Clinical accuracy.
• Consistency with other providers of clinical knowledge for primary care.
• Accuracy of implementation of national guidance (in particular NICE guidelines).
• Usability.

Principles of the consultation process

• The process is inclusive and any individual may participate.
• To participate, an individual must declare whether they have any competing interests or not. If they do not declare whether or not they have competing interests, their comments will not be considered.
• Comments received after the deadline will be considered, but they may not be acted upon before the clinical topic is issued onto the website.
• Comments are accepted in any format that is convenient to the reviewer, although an electronic format is encouraged.
• External reviewers are not paid for commenting on the draft topics.
• Discussion with an individual or an organization about the CKS response to their comments is only undertaken in exceptional circumstances (at the discretion of the Clinical Editor or Editorial Steering Group).
• All reviewers are thanked and offered a letter acknowledging their contribution for the purposes of appraisal/revalidation.
• All reviewers are invited to be acknowledged on the website. All reviewers are given the opportunity to feedback about the external review process, enabling improvements to be made where appropriate.

Stakeholders

• Key stakeholders identified by the CKS team are invited to comment on draft CKS topics. Individuals and organizations can also register an interest to feedback on a specific topic, or topics in a particular clinical area, through the Getting involved section of the Clarity Informatics website.
• Stakeholders identified from the following groups are invited to review draft topics:
  • Experts in the topic area.
  • Professional organizations and societies (for example, Royal Colleges).
  • Patient organizations, Clarity has established close links with groups such as Age UK and the Alzheimer’s Society specifically for their input into new topic development, review of current topic content and advice on relevant areas of expert knowledge.
  • Guideline development groups where the topic is an implementation of a guideline.
  • The British National Formulary team.
  • The editorial team that develop MeReC Publications.
• Reviewers are provided with clear instructions about what to review, what comments are particularly helpful, how to submit comments, and declaring interests.

Patient engagement

Clarity Informatics has enlisted the support and involvement of patients and lay persons at all stages in the process of creating the content which include:

• Topic selection
• Scoping of topic
• Selection of clinical scenarios
• First draft internal review
• Second draft internal review
• External review
• Final draft and pre-publication

Our lay and patient involvement includes membership on the editorial steering group, contacting expert patient groups, organizations and individuals.

Evidence exclusion criteria

Our policy

Scoping a literature search, and reviewing the evidence for CKS is a methodical and systematic process that is carried out by the lead clinical author for each topic. Relevant evidence is gathered in order that the clinical author can make fully informed decisions and recommendations. It is important to note that some evidence may be excluded for a variety of reasons. These reasons may be applied across all CKS topics or may be specific to a given topic.

Studies identified during literature searches are reviewed to identify the most appropriate information to author a CKS topic, ensuring any recommendations are based on the best evidence. We use the principles of the GRADE and PICOT approaches to assess the quality of published research. We use the principles of AGREE II to assess the quality of published guidelines.

Standard exclusions for scoping literature:

• Animal studies
• Original research is not written in English

Possible exclusions for reviewed literature:

• Sample size too small or study underpowered
• Bias evident or promotional literature
• Population not relevant
• Intervention/treatment not relevant
• Outcomes not relevant
• Outcomes have no clear evidence of clinical effectiveness
• Setting not relevant
• Not relevant to UK
• Incorrect study type
• Review article
• Duplicate reference

Organizational, behavioural and financial barriers

Our policy

The CKS literature searches take into consideration the following concepts, which are discussed at the initial scoping of the topic.

• Feasibility
  • Studies are selected depending on whether the intervention under investigation is available in the NHS and can be practically and safely undertaken in primary care.
• Organizational and Financial Impact Analysis
• Studies are selected and evaluated on whether the intervention under investigations may have an impact on local clinical service provision or national impact on cost for the NHS. The principles of clinical budget impact analysis are adhered to, evaluated and recorded by the author. The following factors are considered when making this assessment and analysis.
  • Eligible population
  • Current interventions
  • Likely uptake of new intervention or recommendation
  • Cost of the current or new intervention mix
  • Impact on other costs
  • Condition-related costs
  • In-direct costs and service impacts
  • Time dependencies
• Cost-effectiveness or cost-benefit analysis studies are identified where available. 

We also evaluate and include evidence from NICE accredited sources which provide economic evaluations of recommendations, such as NICE guidelines. When a recommended action may not be possible because of resource constraints, this is explicitly indicated to healthcare professionals by the wording of the CKS recommendation.

Declarations of interest

Our policy

Clarity Informatics requests that all those involved in the writing and reviewing of topics, and those involved in the external review process to declare any competing interests. Signed copies are securely held by Clarity Informatics and are available on request with the permission of the individual. A copy of the declaration of interest form which participants are asked to complete annually is also available on request. A brief outline of the declarations of interest policy is described here and full details of the policy is available on the Clarity Informatics website. Declarations of interests of the authors are not routinely published, however competing interests of all those involved in the topic update or development are listed below. Competing interests include:

• Personal financial interests
• Personal family interest
• Personal non-financial interest
• Non-personal financial gain or benefit

Although particular attention is given to interests that could result in financial gains or losses for the individual, competing interests may also arise from academic competition or for political, personal, religious, and reputational reasons. An individual is not obliged to seek out knowledge of work done for, or on behalf of, the healthcare industry within the departments for which they are responsible if they would not normally expect to be informed.

Who should declare competing interests?

Any individual (or organization) involved in developing, reviewing, or commenting on clinical content, particularly the recommendations should declare competing interests. This includes the authoring team members, expert advisers, external reviewers of draft topics, individuals providing feedback on published topics, and Editorial Steering Group members. Declarations of interest are completed annually for authoring team and editorial steering group members, and are completed at the start of the topic update and development process for external stakeholders.

Competing interests declared for this topic:

None.