Abdominal aortic aneurysm: diagnosis and management

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.

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.

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.

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

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.

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

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.

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

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.

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.

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

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

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).

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.

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.

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.

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 tobacco: preventing uptake, promoting quitting and treating dependence.

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

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

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

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.

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.

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

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.

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.

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

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

• tobacco: preventing uptake, promoting quitting and treating dependence

• diet, nutrition and obesity and exercise

• medicines optimisation

• lipid modification and statin therapy

• diabetes management

• hypertension diagnosis and management.

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

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

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.

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).

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).

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.

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.

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.

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.

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.

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

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

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

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