Recommendations

People have the right to be involved in discussions and make informed decisions about their care, as described in making decisions about your care.

Making decisions using NICE guidelines explains how we use words to show the strength (or certainty) of our recommendations, and has information about prescribing medicines (including off-label use), professional guidelines, standards and laws (including on consent and mental capacity), and safeguarding.

1.1 Diagnosis

Identifying people at risk of abdominal aortic aneurysms

1.1.1 Inform all men aged 66 or over who have not already been screened about the NHS abdominal aortic aneurysm (AAA) screening programme, and advise them that they can self-refer.

1.1.2 Encourage men aged 66 or over to self-refer to the NHS AAA screening programme if they have not already been screened and they have any of the following risk factors:

  • chronic obstructive pulmonary disease (COPD)

  • coronary, cerebrovascular or peripheral arterial disease

  • family history of AAA

  • hyperlipidaemia

  • hypertension

  • they smoke or used to smoke.

1.1.3 Consider an aortic ultrasound for women aged 70 and over if AAA has not already been excluded on abdominal imaging and they have any of the following risk factors:

  • COPD

  • coronary, cerebrovascular or peripheral arterial disease

  • family history of AAA

  • hyperlipidaemia

  • hypertension

  • they smoke or used to smoke.

1.1.4 Be aware that people of European family origin are at a higher risk of an AAA.

Identifying asymptomatic abdominal aortic aneurysms

1.1.5 Offer an aortic ultrasound to people in whom a diagnosis of asymptomatic AAA is being considered if they are not already in the NHS screening programme.

  • Refer people with an AAA that is 5.5 cm or larger to a regional vascular service, to be seen within 2 weeks of diagnosis.

  • Refer people with an AAA that is 3.0 cm to 5.4 cm to a regional vascular service, to be seen within 12 weeks of diagnosis.

1.1.6 Offer an aortic ultrasound to people with a suspected AAA on abdominal palpation.

To find out why the committee made the recommendations on identifying people at risk of AAAs and identifying asymptomatic AAAs and how they might affect practice, see rationale and impact.

Full details of the evidence and the committee's discussion are in evidence review A: risk factors for predicting presence of an abdominal aortic aneurysm and evidence review B: imaging techniques to diagnose abdominal aortic aneurysms.

Identifying symptomatic or ruptured abdominal aortic aneurysms

1.1.7 Think about the possibility of ruptured AAA in people with new abdominal and/or back pain, cardiovascular collapse, or loss of consciousness. Be aware that ruptured AAA is more likely if they also have any of the following risk factors:

  • an existing diagnosis of AAA

  • age over 60

  • they smoke or used to smoke

  • history of hypertension.

1.1.8 Be aware that AAAs are more likely to rupture in women than men.

1.1.9 Offer an immediate bedside aortic ultrasound to people in whom a diagnosis of symptomatic and/or ruptured AAA is being considered. Discuss immediately with a regional vascular service if:

  • the ultrasound shows an AAA or

  • the ultrasound is not immediately available or it is non-diagnostic, and an AAA is still suspected.

To find out why the committee made the recommendations on identifying symptomatic or ruptured AAAs and how they might affect practice, see rationale and impact.

Full details of the evidence and the committee's discussion are in evidence review B: imaging techniques to diagnose abdominal aortic aneurysms and evidence review N: signs, symptoms and risk factors predicting ruptured or symptomatic unruptured aneurysms before arrival at the hospital, and in non-specialist hospital settings.

Imaging technique

1.1.10 When measuring aortic size with ultrasound, report the inner-to-inner maximum anterior-posterior aortic diameter, in accordance with the NHS AAA screening programme. Clearly document any additional measurements taken.

1.1.11 Offer thin-slice contrast-enhanced arterial-phase CT angiography to people who are being evaluated for elective AAA repair.

1.1.12 Consider thin-slice contrast-enhanced arterial-phase CT angiography for people with a suspected ruptured AAA who are being evaluated for AAA repair.

To find out why the committee made the recommendations on imaging technique and how they might affect practice, see rationale and impact.

Full details of the evidence and the committee's discussion are in evidence review B: imaging techniques to diagnose abdominal aortic aneurysms.

Providing information to people with a diagnosed AAA

1.1.13 Give people with AAA of any size information explaining:

  • what an AAA is

  • that most AAAs do not cause any problems

  • that AAAs can rupture, and what this means

  • that AAAs are likely to get larger over time, and that larger AAAs are more likely to rupture

  • that AAA may run in families, so they should tell close relatives that they may have an increased risk of AAA and may need assessment (see recommendations 1.1.2 and 1.1.3)

  • what options for aneurysm repair are available, when repair should be considered and the potential benefits and risks (see recommendations 1.5.1 and 1.5.2), and when it might be better to not have repair (see recommendation 1.1.14)

  • their risk of cardiovascular disease and how this risk can be reduced (see recommendation 1.4.6, and see the section on identifying and assessing cardiovascular disease risk in the NICE guideline on cardiovascular disease).

1.1.14 If AAA repair is not currently suitable for a person, explain why, based on their individual circumstances. For example:

  • Small AAAs only have a very low chance of rupture and there are risks to aneurysm repair, so in this case people do not benefit from repair.

  • AAA growth is unpredictable, so until their AAA meets the criteria in recommendation 1.5.1 it is not possible to know whether repair will be suitable for a particular person.

  • On average, people with poor overall health do not benefit from AAA repair. There is no reliable way to assess whether a particular person will benefit or be harmed, so repair for people with poor overall health is an unnecessary risk even if their AAA meets the criteria in recommendation 1.5.1.

1.1.15 Check that people understand their options, and give them time for reflection and discussion. Encourage them to discuss the options with their family and friends.

1.1.16 For more guidance on providing information, see the section on enabling patients to actively participate in their care in the NICE guideline on patient experience in adult NHS services.

To find out why the committee made the recommendations on providing information to people with a diagnosed AAA and how they might affect practice, see rationale and impact.

Full details of the evidence and the committee's discussion are in evidence review K: effectiveness of endovascular aneurysm repair, open surgical repair and non-surgical management of unruptured abdominal aortic aneurysms.

1.2 Monitoring and reducing the risk of rupture

Reducing the risk of rupture

1.2.1 Offer a referral to a stop smoking service to people with an abdominal aortic aneurysm (AAA) who smoke. For more guidance, see the NICE guideline on stop smoking interventions and services.

1.2.2 Ensure that people with an AAA who have hypertension receive care in line with the NICE guideline on hypertension in adults.

To find out why the committee made the recommendations on reducing the risk of rupture and how they might affect practice, see rationale and impact.

Full details of the evidence and the committee's discussion are in evidence review C: risk factors associated with abdominal aortic aneurysm growth or rupture.

Monitoring the risk of rupture

1.2.3 Offer surveillance with aortic ultrasound to people with an asymptomatic AAA. Use the same surveillance frequency as the NHS AAA screening programme.

1.2.4 See recommendation 1.1.5 on when to refer people to a regional vascular unit.

To find out why the committee made the recommendations on monitoring the risk of rupture and how they might affect practice, see rationale and impact.

Full details of the evidence and the committee's discussion are in evidence review D: monitoring for abdominal aortic aneurysm expansion and risk of rupture.

1.3 Emergency transfer to regional vascular services

1.3.1 Be aware that there is no evidence that any single symptom, sign or prognostic risk assessment tool can be used to determine whether people with a suspected or confirmed ruptured abdominal aortic aneurysm (AAA) should be transferred to a regional vascular service.

1.3.2 When making transfer decisions, be aware that people with a confirmed ruptured AAA who have a cardiac arrest and/or have a persistent loss of consciousness have a negligible chance of surviving AAA repair.

1.3.3 For guidance on care of people with a ruptured AAA for whom repair is considered inappropriate, see the NICE guideline on care of dying adults in the last days of life.

1.3.4 When people with a suspected ruptured or symptomatic unruptured AAA have been accepted by a regional vascular service for emergency assessment, ensure that they leave the referring unit within 30 minutes of the decision to transfer.

1.3.5 Emergency departments, ambulance services and regional vascular services should collaborate to:

  • provide a protocol for the safe and rapid transfer of people with a suspected ruptured or symptomatic unruptured AAA who need emergency assessment at a regional vascular service

  • train clinical staff involved in the care of people with a suspected ruptured or symptomatic unruptured AAA in the transfer protocol

  • review the transfer protocol at least every 3 years.

To find out why the committee made the recommendations on emergency transfer to regional vascular services and how they might affect practice, see rationale and impact.

Full details of the evidence and the committee's discussion are in evidence review O: signs, symptoms and risk factors indicating suitability for transfer to a regional vascular service and evidence review P: time period for transfer to regional vascular services.

Supporting people during transfer

1.3.6 Consider a restrictive approach to volume resuscitation (permissive hypotension) for people with a suspected ruptured or symptomatic AAA during emergency transfer to a regional vascular service.

To find out why the committee made the recommendation on supporting people during transfer and how it might affect practice, see rationale and impact.

Full details of the evidence and the committee's discussion are in evidence review Q: permissive hypotension during transfer of people with ruptured abdominal aortic aneurysm to regional vascular services.

1.4 Predicting and improving surgical outcomes

Predicting surgical outcomes for unruptured aneurysms

1.4.1 Consider cardiopulmonary exercise testing when assessing people for elective repair of an asymptomatic abdominal aortic aneurysm (AAA), if it will assist in shared decision making.

1.4.2 For guidance on other preoperative tests, see the NICE guideline on routine preoperative tests for elective surgery.

1.4.3 Do not use the following risk assessment tools to determine whether or not repair is suitable for a person with an asymptomatic unruptured AAA:

  • British Aneurysm Repair score

  • Carlisle Calculator

  • Comorbidity Severity Score

  • Glasgow Aneurysm Scale

  • Medicare risk prediction tool

  • Modified Leiden score

  • Physiological and Operative Severity Score for enUmeration of Mortality (POSSUM)

  • Vascular-POSSUM

  • Vascular Biochemical and Haematological Outcome Model (VBHOM)

  • Vascular Governance North West (VGNW) risk model.

To find out why the committee made the recommendations on predicting surgical outcomes for unruptured aneurysms and how they might affect practice, see rationale and impact.

Full details of the evidence and the committee's discussion are in evidence review G: tests for predicting outcomes after repair of unruptured abdominal aortic aneurysms and evidence review H: risk assessment tools for predicting surgical outcomes of patients who undergo elective abdominal aortic aneurysm repair.

Predicting surgical outcomes for ruptured aneurysms

1.4.4 Do not use any single symptom, sign or patient-related risk factor to determine whether aneurysm repair is suitable for a person with a ruptured AAA.

1.4.5 Do not use patient risk assessment tools (scoring systems) to determine whether aneurysm repair is suitable for a person with a ruptured AAA.

To find out why the committee made the recommendations on predicting surgical outcomes for ruptured aneurysms and how they might affect practice, see rationale and impact.

Full details of the evidence and the committee's discussion are in evidence review S: risk factors for predicting survival after abdominal aortic aneurysm rupture.

Improving surgical outcomes

1.4.6 Offer people with an AAA information, support and interventions for secondary prevention of cardiovascular disease. For more information refer to the NICE guidance on:

1.4.7 Do not routinely offer preoperative beta blockers to people having AAA repair.

1.4.8 Do not offer remote ischaemic preconditioning to people having AAA repair.

1.4.9 For guidance on preventing and treating surgical site infections and on preventing venous thromboembolism, see the NICE guidelines on surgical site infections and reducing the risk of venous thromboembolism.

To find out why the committee made the recommendations on improving surgical outcomes and how they might affect practice, see rationale and impact.

Full details of the evidence and the committee's discussion are in evidence review J: pre- and postoperative interventions to optimise outcomes after abdominal aortic aneurysm repair.

1.5 Repairing unruptured aneurysms

When to consider repair

1.5.1 Consider aneurysm repair for people with an unruptured abdominal aortic aneurysm (AAA), if it is:

  • symptomatic

  • asymptomatic, larger than 4.0 cm and has grown by more than 1 cm in 1 year (measured inner-to-inner maximum anterior-posterior aortic diameter on ultrasound)

  • asymptomatic and 5.5 cm or larger (measured inner-to-inner maximum anterior-posterior aortic diameter on ultrasound).

Discussing the benefits and risks of repair or conservative management

1.5.2 When discussing aneurysm repair with people who have an unruptured AAA, explain the overall balance of benefits and risks with repair and with conservative management, based on their current health and their expected future health. The decision on whether repair is preferred over conservative management should be made jointly by the person and their clinician after assessment of a number of factors, including:

  • aneurysm size and morphology

  • the person's age, life expectancy, fitness for surgery, and any other conditions they have

  • the risk of AAA rupture if they do not have repair

  • the short- and long-term benefits and risks, and the other disadvantages of repair such as having to stay in hospital, the risks of the operation, the recovery period, the potential need for further procedures and the need for surveillance imaging appointments

  • the uncertainties around estimates of risk for AAAs larger than 5.5 cm (measured inner-to-inner maximum anterior-posterior aortic diameter on ultrasound).

Open surgical repair, standard endovascular aneurysm repair or conservative management

1.5.3 Offer open surgical repair for people with unruptured AAAs meeting the criteria in recommendation 1.5.1, unless it is contraindicated because of their abdominal copathology, anaesthetic risks, and/or medical comorbidities.

1.5.4 Consider endovascular aneurysm repair (EVAR) for people with unruptured AAAs who meet the criteria in recommendation 1.5.1 and who have abdominal copathology, such as a hostile abdomen, horseshoe kidney or a stoma, or other considerations, specific to and discussed with the person, that may make EVAR the preferred option.

1.5.5 Consider EVAR or conservative management for people with unruptured AAAs meeting the criteria in recommendation 1.5.1 who have anaesthetic risks and/or medical comorbidities that would contraindicate open surgical repair.

Complex endovascular aneurysm repair

1.5.6 If open surgical repair and complex EVAR are both suitable options, only consider complex EVAR if:

  • the following has been discussed with the person:

    • the risks of complex EVAR compared with the risks of open surgical repair

    • the uncertainties around whether complex EVAR improves perioperative survival or long-term outcomes, when compared with open surgical repair

  • it will be performed with special arrangements for consent and for audit and research that will determine the clinical and cost effectiveness of complex EVAR when compared with open surgical repair, and all patients are entered onto the National Vascular Registry.

1.5.7 For people who have anaesthetic risks and/or medical comorbidities that would contraindicate open surgical repair, only consider complex EVAR if:

  • the following has been discussed with the person:

    • the risks of complex EVAR compared with the risks of conservative management

    • the uncertainties around whether complex EVAR improves perioperative survival or long-term outcomes

  • it will be performed with special arrangements for consent and for audit and research that will determine the clinical and cost effectiveness of complex EVAR when compared with conservative management, and all patients are entered onto the National Vascular Registry.

NICE amended recommendations 1.5.1 to 1.5.7, after the committee's proposed recommendations were reviewed by NICE's Board.

To find out why the recommendations on repairing unruptured aneurysms were made and how they might affect practice, see rationale and impact.

Full details of the evidence and the committee's discussion are in:

Anaesthesia and analgesia

1.5.8 Consider epidural analgesia in addition to general anaesthesia for people having open surgical repair of an unruptured AAA.

To find out why the committee made the recommendation on anaesthesia and analgesia for repair of unruptured aneurysms and how they might affect practice, see rationale and impact.

Full details of the evidence and the committee's discussion are in evidence review L: anaesthesia and analgesia for people having surgical repair of an abdominal aortic aneurysm.

1.6 Repairing ruptured aneurysms

1.6.1 Consider endovascular aneurysm repair (EVAR) or open surgical repair for people with a ruptured infrarenal abdominal aortic aneurysm (AAA). Be aware that:

  • EVAR provides more benefit than open surgical repair for most people, especially men over 70 and women of any age

  • open surgical repair is likely to provide a better balance of benefits and harms in men under 70.

1.6.2 Consider open surgical repair for people with a ruptured AAA if standard EVAR is unsuitable.

1.6.3 Do not offer complex EVAR to people with a ruptured AAA if open surgical repair is suitable, except as part of a randomised controlled trial comparing complex EVAR with open surgical repair.

To find out why the committee made the recommendations on repairing ruptured aneurysms and how they might affect practice, see rationale and impact.

Full details of the evidence and the committee's discussion are in evidence review T: effectiveness of endovascular aneurysm repair compared with open surgical repair of ruptured abdominal aortic aneurysms.

Anaesthesia and analgesia

1.6.4 Consider using local infiltrative anaesthesia alone for people having EVAR of a ruptured AAA.

To find out why the committee made the recommendation on anaesthesia and analgesia and how it might affect practice, see rationale and impact.

Full details of the evidence and the committee's discussion are in evidence review L: anaesthesia and analgesia for people having surgical repair of an abdominal aortic aneurysm.

Abdominal compartment syndrome

1.6.5 Be aware that people can develop abdominal compartment syndrome after EVAR or open surgical repair of a ruptured AAA.

1.6.6 Assess people for abdominal compartment syndrome if their condition does not improve after EVAR or open surgical repair of a ruptured AAA.

To find out why the committee made the recommendations on abdominal compartment syndrome and how they might affect practice, see rationale and impact.

Full details of the evidence and the committee's discussion are in evidence review U: preventing abdominal compartment syndrome following repair of ruptured abdominal aortic aneurysm.

1.7 Monitoring for complications after endovascular aneurysm repair

1.7.1 Enrol people who have had endovascular aneurysm repair (EVAR) into a surveillance imaging programme.

1.7.2 Base the frequency of surveillance imaging on the person's risk of EVAR-related complications.

1.7.3 Consider contrast-enhanced CT angiography or colour duplex ultrasound for assessing abdominal aortic aneurysm (AAA) diameter and EVAR device limb kinking.

1.7.4 Use contrast-enhanced CT angiography if an endoleak is suspected. If contrast-enhanced CT angiography is contraindicated, use contrast-enhanced ultrasound.

1.7.5 Do not exclude endoleaks based on a negative colour duplex ultrasound alone in people who have had EVAR.

To find out why the committee made the recommendations on monitoring for complications after endovascular aneurysm repair and how they might affect practice, see rationale and impact.

Full details of the evidence and the committee's discussion are in evidence review V: postoperative surveillance after surgical repair of abdominal aortic aneurysms and evidence review W: accuracy of imaging techniques in identifying complications after surgery.

1.8 Managing endoleaks after endovascular aneurysm repair

1.8.1 Consider open, endovascular or percutaneous intervention for type 1 and type 3 endoleaks following endovascular aneurysm repair (EVAR).

1.8.2 Consider intervention for type 2 endoleaks in people who have abdominal aortic aneurysm (AAA) expansion following EVAR.

1.8.3 Consider further investigation of type 5 endoleaks following EVAR.

To find out why the committee made the recommendations on managing endoleaks after endovascular aneurysm repair and how they might affect practice, see rationale and impact.

Full details of the evidence and the committee's discussion are in evidence review X: managing complications after abdominal aortic aneurysm repair.

Terms used in this guideline

This section defines terms that have been used in a specific way for this guideline. For general definitions, please see the NICE glossary.

Standard and complex EVAR

Standard EVAR is defined as any EVAR procedure:

  • using a standard infrarenal device (an unmodified off-the-shelf stent graft) and

  • following the manufacturer's 'instructions for use' for the device used and

  • without any adjunctive procedures (planned use of endo-anchors and planned permanent instrumentation of aortic branch vessels, such as 'chimney' or 'snorkel' procedures).

Any EVAR procedure that does not fit into the definition above is classed as 'complex EVAR'. Complex EVAR also covers fenestrated, branched, customised or internal iliac branch devices, and physician-modified stent grafts.

Endoleak

The persistence of blood flow outside an endovascular stent–graft but within the aneurysm sac in which the graft is placed. There are 5 types of endoleak:

  • Type 1 – blood flowing into the aneurysm because of an incomplete or ineffective seal at either end of a stent–graft

  • Type 2 – blood flowing into an AAA from side branches of the aorta

  • Type 3 – blood flowing into an AAA through defects in the endograft

  • Type 4 – blood flowing through the stent–graft fabric into an AAA

  • Type 5 – continued AAA expansion without radiographic evidence of a leak site.

Hostile abdomen

An abdomen that is difficult to perform open surgery within, because of adverse anatomical features. For AAA repair, these features can include large abdominal wall defects or intra-abdominal adhesions. A hostile abdomen is most common in people who have had multiple previous episodes of intra-abdominal open surgery.

Infrarenal abdominal aortic aneurysm

An abdominal aortic aneurysm arising below the arteries that supply the kidneys.

Permissive hypotension

A method of fluid administration that aims to reduce bleeding by keeping a person's blood pressure within a lower-than-normal range.

  • National Institute for Health and Care Excellence (NICE)