Guidance

AAA screening: Monitoring waiting times to surgery

Updated 24 February 2025

Applies to England

1. Introduction

This section explains the rationale and process for monitoring men who have exceeded the NHS AAA Screening Programme standard 8-week (56 days) timescale for treatment.

This section should be read in conjunction with the NHS AAA Screening Programme screening standards[i].

2. Background

Waiting times to surgery are important standards in the NHS AAA Screening Programme to reduce the risk of AAA related death or AAA rupture. Prior to the COVID-19 pandemic, NHS England worked with local screening services which resulted in improvements in waiting times for men to be seen in outpatients and some improvement in waiting times for treatment. However, national standards for waiting times to surgery have not yet been achieved by all AAA screening services.

The two standards for men referred to surgery recognise that not every man referred for surgery will be immediately suitable for repair, either permanently or temporarily. There may be practical reasons why there are delays in the pathway, for instance where a customised stent must be ordered. There will also be some men who choose to defer or decline treatment. Therefore, there will be good reason for men who wait longer than 8 weeks (56 days) to be operated on. The acceptable threshold[ii]  has been set at 60% to take account of these cases.

Men waiting over 12 weeks (84 days) for surgery from their scan are classified as having a long wait. Men with a long wait are expected to be a small proportion of the referrals not meeting the 8-week time frame. 

The national IT system, SMaRT, allows local services to record reasons for delays in the referral pathway so that avoidable and non-avoidable factors can be identified. Screening services should have local trackers and processes in place to review and escalate any issues with regional commissioners and specialised vascular service providers.

3. Waiting times standards valid from April 2022

Screening standard 14: Proportion of men with an aorta ≥5.5cm appropriately referred, or an aorta ≥4.0cm that has grown ≥1cm in 1 year, seen by vascular surgeon ≤2 weeks of their last conclusive ultrasound scan.

Thresholds:

• acceptable: ≥90%
• achievable: ≥95%

Screening standard 15: Proportion of men with an aorta ≥5.5cm appropriately referred, or an aorta ≥4.0cm that has grown ≥1cm in 1 year, deemed fit for intervention and not declining, and operated on by a vascular surgeon ≤8 weeks of their last conclusive ultrasound scan.

Thresholds:

• acceptable: ≥60%
• achievable: ≥80%

4. Assessment of suitability for surgery

Men who accept referral for surgery should be seen by a vascular surgeon within 2 weeks of their scan and follow the standard investigation pathway for that organisation.

The investigations will result in one of the following outcomes:

• the man is suitable for intervention and has an open infrarenal AAA repair or endovascular repair planned
• the man has been inappropriately referred, for example, an AAA < 5.5cm or does not have AAA or an aorta ≥ 4.0cm that has not grown ≥1cm in 1 year
• the man has complex anatomy and requires referral to a tertiary centre
• the man will never be fit for surgery and is turned down for intervention
• the man requires further investigation and/or treatment in another speciality before a decision can be made about his AAA repair

If the length of treatment and recovery in another specialty is likely to be more than 12 months, the man can be recorded on SMaRT as unsuitable for surgery. If treatment and recovery is likely to be less than 12 months then the service should continue to record his delay reasons on SMaRT until he is operated on, declines, or is formally turned down for surgery.

In some cases, following clinical assessment and decision by a vascular specialist/multidisciplinary team meeting, surgery may be delayed until the man reaches a larger aortic diameter so that the risk of mortality from surgery is lower than the risk of rupture. These men can also be recorded as unsuitable for surgery within SMaRT. The men recorded as unsuitable for surgery, as described in the scenarios above, should continue to be monitored on surveillance within the vascular service. If surgery does occur and is entered on the National Vascular Registry (NVR), the information will be automatically transferred into SMaRT.

Men who decline (declines can occur at any point in the pathway), are unsuitable for surgery or who were inappropriately referred, are not included in the denominator for standard 15.

5. Monitoring long waiting AAA men

Any individual case waiting over 12 weeks (84 days) for treatment should be identified and their pathway reviewed. If there are any unacceptable hospital reason(s) for delay, this should be investigated by the treatment pathway provider and reported to regional commissioners, who will liaise with specialist commissioners as required.  

Acceptable reasons for not having surgical repair include:

• medical reasons - undergoing medical treatment for cardiac (angioplasty/bypass), respiratory (incidental lung cancer) or other conditions that would otherwise increase the risks of intervention for AAA
• technical reasons - computed tomography angiography shows complex AAA (juxtarenal or thoracoabdominal) that either needs:
  • more complex treatment (where a branched or fenestrated stent is required)
    or
  • referral to a tertiary centre (referrals to a tertiary centre should continue to be monitored to determine outcomes and to ensure timely management)
  • patient factors - patient declines or defers treatment

Unacceptable reasons include hospital factors such as:

• delays in investigations
• delays in multi-disciplinary team meetings
• delays in outpatient appointments
• staffing availability, capacity, or lack of critical care beds
• delays in treatment after the stent has been made available
• surgery cancelled at short notice, for example clinical emergency taking priority

Any avoidable delays that occur within the screening pathway (such as a referral not made, delayed or not received) should be reported to the responsible Public Health Commissioning team and SQAS for advice on reporting i.e. completion of SIAF.

Any man who dies whilst in the screening pathway should be recorded on SMaRT, including those who have an AAA ≥ 5.5cm and are waiting for treatment after referral. These deaths should be notified to the responsible Public Health Commissioning team and SQAS who will advise on appropriate investigation.

Where a man is waiting over 8 weeks and experiences a ruptured AAA, but does not die, a clear transparent process must be in place for a clinical harm review to identify the impact of the extended wait.

There may be an acceptable reason for delay, and this should be identified in the initial assessment process.

6. Tracking referrals

For any man referred, it is the screening service’s responsibility to track each referral with the receiving specialised vascular service provider and ensure they monitor any delays in the man being seen for assessment or subsequent treatment. Men referred to a tertiary centre should also be monitored by the screening service who referred the man.

Delays should be recorded on SMaRT with new reasons for delay entered as appropriate[iii]. Some men may have multiple reasons for delay, and these should all be recorded. For example, a man may initially delay by choice and then be delayed while waiting for a stent. Local services should receive final outcomes for each man referred.

The screening service should ensure that appropriate systems are in place to support a high-quality interface between screening and treatment services.

This should include:

• developing joint audit and monitoring processes
• agreeing jointly what failsafe mechanisms are required to ensure safe and timely processes across the whole screening pathway

Routine reports on waiting times performances should be prepared by the local service and discussed at local programme board meetings. The trust or host organisation board responsible for the screening service should also receive the routine reports. These reports must show performance against both waiting times standards and the actions being taken to improve and sustain performance.

These reports should be presented in a way that allows the Trust/host organisation board to see the number and proportion of men with long waits as defined above. Where required, the Trust/host organisation board should see the outcomes of any incident investigation reports and may request further forms of exception reporting as required by local circumstances.

7. References

[i] AAA screening standards

Abdominal aortic aneurysm screening programme: standards - GOV.UK (www.gov.uk)

[ii]   Acceptable threshold

UK National Screening Committee: screening in healthcare - Guidance - GOV.UK (www.gov.uk)

[iii]    Guidance for the waiting times tracker report

AAA screening: guidance for the waiting times tracker report - GOV.UK (www.gov.uk)