Guidance

Screening pathway

Updated 1 October 2024

The screening procedure is divided into the following stages:

• identification
• invitation
• informing
• testing
• surveillance
• diagnosis
• treatment and intervention
• monitoring outcomes

1. Identification

Each local AAA service will have access to their entire cohort list approximately 5 months prior to the start of the screening year to allow for clinic planning. This will come via the national software solution. The unique identifier for each man will be the NHS number.

1.1 Clinic booking

It is suggested that screening clinics are scheduled to last 3 to 4 hours and appointment slots are usually allocated at 5 or 10-minute intervals with a short break mid-session. There should be 2 staff to cover each clinic. Generally, 15 to 18 men would be seen over 3 hours. However, the number should be reduced if:

• there are newly qualified screening technicians who are gaining experience
• more than 5 surveillance subjects are to be included
• it is a new screening location

2. Invitation

Eligible men are invited by letter to one of the dedicated screening clinics held in a variety of locations within their community. The invitation will come from the local screening office and not the GP.

If a local screening service receives its cohort ‘early’ – in other words before the year (1 April to 31 March) that the men turn 65 – it should avoid inviting men for screening when they are still aged 63. However, it is acceptable to invite men for screening as soon as they have turned 64, even if the date of screening falls before the start of their cohort year.

If a man is invited for screening when he is still aged 63, his local programme should use the following wording if the man subsequently asks why he has been invited:

“The NHS AAA Screening Programme usually invites men for screening during the year they turn 65. This is because most AAA occur in men aged 65 and over. However, some men may be invited for screening shortly before their 64th birthday. Inviting men for screening ‘a few months early’ is not clinically significant.”

All call and recall appointments must be organised at, and generated from, the central administrative office within the screening programme. The local screening service will generate and send invitations using the cohort list of subjects within the IT system.

An invitation pack should include:

• an appointment detailing a specific date, time and location. This letter should also ask men with special requirements (such as mobility, hearing or visual) to contact the screening office in order to arrange an appointment at a separate dedicated clinic if applicable
• the national invitation leaflet
• a direction sheet with map (unless the location is the subject’s own GP practice)
• an address/phone number/email address to contact the screening centre

It is important that invited men can give informed consent to be screened. For non-English speakers, translations of the national information leaflets and consent forms are available to download and print out. Local services should arrange any required interpreter services through their trust.

3. Informing

The man will be seen by the screening technician on arrival at the screening clinic. This will allow further information about screening to be given before the decision to participate is taken.

Care should be taken to ensure the identity of the person being screened is securely established by:

• asking to see the letter of appointment where possible, and double checking the NHS number against the subject record both on SMaRT and on the ultrasound machine. If SMaRT is unavailable the NHS number must be checked against the clinic list and all details entered on the proforma
• asking the individual to state their full name, address and date of birth rather than asking them to confirm their details as read to the individual, and checking that the details match the subject record

The man should be fully informed about the process and possible outcomes. This information should also include an explanation regarding the use of his data. His full consent should be obtained prior to screening commencing.

4. Testing

Screeners take views of the abdominal aorta using ultrasonography, noting that:

• two anterior–posterior (AP) measurements of the maximum aortic diameter should be recorded in centimetres, to one decimal place, measured across the lumen from/to the inside of the ultrasound-detected aortic wall – one with the probe in the longitudinal plane and one with the probe in the transverse plane
• it is recommended that all images should be annotated TS for transverse section and LS for longitudinal section. Alternatively, the body marker pictogram can be used
• patient details are usually loaded from the worklist generated by SMaRT, but if a man needs to be added to the scanner manually it is vital to ensure that the NHS number, subject’s last name and date of birth are provided
• technicians should also check that the Institution Name and/or Referring Physician fields are completed with the 3-character programme prefix
• the use of coronal imaging planes should be avoided and is not part of the screening protocol. Additionally, screeners should not attempt to use colour or spectral Doppler modes on the scanning equipment. Further details regarding the scan can be found in the clinical guidance document

All men entering the programme should follow the national process and pathway outlined. However, it is acknowledged that in some areas there will be existing surveillance patients who have previously had their aortic diameter results based on different measuring criteria. These men, on their next follow-up scan, should be provided with a clear explanation regarding the changes in measuring criteria based on the national screening programme, the result of which may see the diameter of the aorta reduced compared to their previous scan. Clear information following their scan should also be given which will need to explain any change to their surveillance pathway. It is important that these men understand this does not necessarily mean their aortic aneurysm has reduced in size.

The images are assessed at the time of screening to determine whether an AAA of 3cm or greater has been detected, and the aortic diameter measurements are recorded. A minimum of 2 static sonographic images, including normal, abnormal or non-visualised results, should be recorded and stored to allow recall in cases of serious incident and for quality assurance purposes. In cases where the aorta cannot be seen local programme staff should refer to the guidance for management of non-visualised screening results.

All screening results should also be recorded in writing on a printed work sheet at each clinic. These work sheets are submitted to the local programme co-ordinator who checks and files them for audit, quality assurance and fail-safe purposes.

Any result outcome should be communicated to all subjects verbally and in writing to those men in whom an aneurysm is found. If this has not been possible, the result should be sent as soon as possible to the GP and clinicians providing other care. It is not acceptable to operate under the principle that ‘no news is good news’.

If the maximum aortic diameter is less than 3cm, the subject is advised that no aneurysm has been detected and no further follow-up will be arranged.

If the maximum aortic diameter is 3cm or greater, the subject is advised that an aneurysm has been detected and given the appropriate explanatory information leaflet. They are informed that a further follow-up will be arranged either at a future screening clinic at a specified time interval, or at a hospital outpatient clinic with a vascular specialist.

If an AAA of ≥5.5cm is identified, the screening office is contacted urgently by telephone from the clinic in order that arrangements may commence for a referral to a vascular surgeon in line with the pathway standards

If the aortic diameter cannot be visualised, the subject is invited for one further scan at another screening clinic if thought appropriate – for example due to transient bowel gas – or by the vascular lab/medical imaging department at the hospital. If the outcome is still non-visualised at a second screening scan, then the subject must be referred to the vascular lab/medical imaging department. Guidance should be offered recommending minimum food and drink intake in the 4-hour period prior to the proposed scan.

The vascular lab/medical imaging department should notify the screening office of the outcome of the scan and it is the responsibility of the office to send the correct information and action accordingly depending on the presence and size of an aneurysm. Surveillance subjects should be followed up in the community screening programme unless this is otherwise advised.

If the aorta still cannot be visualised after this imaging scan, then individual cases must be discussed with the clinical director. CT/MRI scanning as routine is not considered to be cost effective and has associated risks. This should not be carried out unless considered important by the clinical director, considering the wishes and circumstances of the man involved. The clinical director should come to an agreement with local commissioners and providers as to who would fund this additional imaging, should it be deemed appropriate.

All programmes should ensure that their screening technicians have been appropriately trained and assessed as competent to give verbal feedback at the time of the scan. It is important to note that before a screening technician can give verbal feedback, they must have received confirmation that they have passed the training course – submission of the portfolio is not sufficient. Screening staff should:

• not carry out any additional abdominal scanning during a screening appointment
• have a local process for incidental findings developed and in place
• discuss any anomalous findings, for example clear dilation/saccular bulges when the aorta is below 3cm, with the clinical director or the imaging lead and document them as per local process
• enter screening results directly onto SMaRT if available

4.1 After the clinic (at the office)

Screening staff should ensure that:

• result letters are sent to subjects with aneurysms requiring surveillance and for those requiring a referral. Letters are not sent to men with normal aortic measurements
• results are sent to GPs within one week for all subjects regardless of the result
• data from the clinic is reviewed to ensure that information has been fully and correctly recorded
• images are uploaded to SMaRT and checked against the clinic list of scanned patients
• if the aorta cannot be visualised at the screening clinic, a further scan should be arranged at a later screening clinic or local hospital vascular lab/medical imaging department
• the co-ordinator makes appropriate referrals to a vascular surgeon for patients who have an AAA ≥5.5 cm and informs the GP within one working day of the clinic
• at least one further invitation should be sent to those not attending their first appointment without notification to the programme
• local policy takes into account the pursuit of non-responders such as checking contact details with the GP practice - it is essential that GPs are contacted via telephone with letter/email follow-up regarding the non-attendance of a surveillance patient and the actions taken, including any reason for the non-attendance recorded in case of future rupture of the aneurysm
• standard result letters are available and should be used with minimal local amendment to the template only and not to the core content

5. Surveillance

Follow-up appointments will be arranged if the AAA is large enough.

If it measures 3.0 to 4.4 cm, a follow up will be in one year.

If it measures 4.5 to 5.4 cm, a follow up will be in 3 months.

5.1 Forward planning

Details should be checked, and any changes made to the IT system. Checks should be made that:

• subject is not deceased
• subject’s address has not changed
• the GP has not indicated that the subject is unsuitable for surveillance

It is important to note that:

• it is unreasonable to expect surveillance subjects to attend clinics at different venues on successive occasions as this increases their anxiety
• screening clinics should include a mixture of surveillance subjects and those attending their first screening appointment to ensure that staff regularly have the opportunity to scan AAA subjects. This ensures that they maintain their skills and adds interest to the clinics
• the number of subjects booked at each clinic will vary according to the number of subjects under surveillance who are included and the experience of the staff. Generally, patients are allocated a single slot at 5 to 10-minute intervals over a 3 to 4-hour session
• if subjects request a delay or change in the appointment, or if a further appointment is declined or deemed inappropriate, the IT system should be updated accordingly. The updated clinic list is then available to staff on the day of the clinic

5.2 At the clinic

Screening results should:

• be communicated to all subjects verbally at the clinic and, if an aneurysm has been detected, in writing using the standard letter templates
• indicate if a further scan is planned and if so the approximate surveillance interval.
• results should be entered directly on to the SMaRT system if available
• screening results and paperwork are returned to the office, including a printout of the clinic list with screening measurements in writing against each subject

If an AAA ≥5.5 cm is identified:

• the screening office must be contacted urgently by telephone from the clinic for a referral to a vascular surgeon without delay
• the technicians should inform the subject that he should contact the Driver and Vehicle Licensing Agency (DVLA)
• bus, coach and lorry drivers will have their license suspended – it will be reinstated once the aneurysm has been successfully treated
• car drivers must inform the DVLA once the aneurysm reaches 6cm, and the license will be suspended once the aneurysm reaches 6.5cm – it will be reinstated once the aneurysm has been successfully treated

5.3 After the clinic (at the office)

Screening staff should ensure that:

• result letters are sent to subjects with aortas measuring ≥3.0 cm
• results are sent to GPs
• data from the clinic is reviewed by the programme co-ordinator to ensure information has been fully and correctly recorded
• if the aorta could not be visualised at the screening clinic a further scan should be arranged either at a subsequent screening session or at a local hospital vascular lab/medical imaging department
• the co-ordinator makes appropriate referrals to a vascular surgeon for patients who have an AAA of ≥5.5 cm and informs the GP within one working day of the clinic
• it is essential that GPs are contacted via telephone with letter/email follow-up regarding the non-attendance of a surveillance patient and the actions taken; including any reason for the non-attendance recorded in case of future rupture of the aneurysm
• standard result letters should be used with minimal local amendments to the template only and not to the core content

6. Informed dissent

Subjects with small or medium abdominal aortic aneurysms who indicate that they do not wish to be re-screened should be encouraged to remain in the surveillance recall system and decline their next individual regular invitation rather than withdraw permanently. However, any subject who indicates that he is certain of his decision should have this decision respected.

Men must be provided with sufficient information to enable an informed decision to be made about withdrawing from the screening programme. This must be in a format which is accessible, and men must be informed that withdrawing from the programme will prevent them from receiving any future invitations or reminders about screening. However, it must be made clear that they may return to the programme at any time at their own request.

Additionally, men must be capable of making and communicating an informed decision. Under the Mental Capacity Act 2005, individuals must be presumed to have capacity to make their own decisions unless it is proved otherwise. Ceasing decisions for people who lack mental capacity may be made by a legally-accountable decision-maker only where the individual cannot make his own decision even with support and assistance and must always be in the individual’s best interests. This is likely to be appropriate only where the man would never be suitable for further investigations or treatment should his aneurysm increase in size. Decision makers are required to document the decision-making process and retain an auditable record of this.

Wherever possible, a specifically-written instruction should be signed by the subject or his representative to confirm his informed dissent from surveillance recall. Each screening office must have fully defined and documented protocols for ceasing, and these must be available to all staff who deal with queries from screening subjects and the general public.

Individuals who have confirmed their wish to be removed from the screening programme should receive no further correspondence relating to any screening episode. Unless the subject has specifically requested otherwise, the screening office must write to him to confirm that recall has ceased and to give instructions on how to rejoin the programme if required.

6.1 Nurse practitioner/health promotion clinics

Men will be offered an appointment to see a nurse practitioner/vascular nurse at or before their first surveillance scan (at 3 months or 12 months) and an opportunity to see the nurse when they move from annual surveillance to 3-monthly surveillance. How these appointments are arranged will be a local decision and may be at the same clinic as the follow-up scan – leaving the screening technician to carry out the scanning – or at a dedicated separate clinic.

6.2 Subject

Following a positive screen with the aorta measuring 3cm to 5.4cm, the subject will be given an appropriate surveillance information leaflet.

The screening office will then send an accompanying letter confirming the outcome of the screening test and will inform the man that before his next scan he will be contacted by a nurse practitioner/vascular nurse who will invite him to an appointment to answer any questions he may have and to provide him with some advice should he want it. This appointment may be before or at the same time as his next scan.

6.3 GP

Following a positive screen with the aorta measuring 3cm to 5.4cm, the GP will be sent a letter giving:

• the result of scan, including the size of the aneurysm
• an outline of the interval for the next scan
• information that the nurse practitioner or vascular nurse will contact the patient to invite him to an appointment for support, reassurance and lifestyle advice

6.4 Appointment details

The appointment will be a one-off unless the man contacts the programme co-ordinator expressing undue anxiety or he is moving from 12-month surveillance to 3-month surveillance.

The appointment letter should state that the appointment is being offered should he wish to accept it and that, if attending, the patient should bring details of any prescribed medication with him.

During the appointment the nurse practitioner/vascular nurse should:

• measure and record height and weight
• calculate and record body mass index (BMI) using National Institute for Health and Clinical Excellence (NICE) guidelines
• determine smoking status – never smoked, used to smoke, currently smoking
• provide smoking cessation advice as per local guidance
• measure and record blood pressure (more than once)
• ask whether the man is currently taking statins and if so, which
• ask whether the man is currently taking antiplatelets (aspirin or clopidogrel)
• determine and record any patient concerns
• recommend any interventions such as seeing GP
• provide lifestyle advice as per NICE guidelines and record
• provide reassurance regarding size and presence of AAA
• ensure all measurements and recommendations are recorded and transferred to the screening office for input into the SMaRT system
• send letter to GP within one week outlining outcome of appointment
• send letter to subject outlining recommendations

7. Diagnosing

If the AAA measures 5.5cm or greater, the subject should be informed verbally at the clinic of the need to be referred to a vascular consultant in a hospital outpatient department, and the reasons for this referral explained. This verbal confirmation should be followed up with written confirmation. He should also be given the appropriate referral information booklet. If a subject declines a referral then confirmation of this should be sent to him and the GP indicating that he is free to change his mind at any time. It is important that this is done in case of later rupture.

The subject should be informed that he should contact the DVLA regarding his aneurysm. They must state whether they are a:

• bus, coach or lorry driver – he will have their license suspended, but this will be reinstated once the aneurysm has been treated successfully
• car driver - he must inform the DVLA once the aneurysm reaches 6cm, and the license suspended once the aneurysm reaches 6.5cm. The license will be reinstated once the aneurysm has been treated successfully

The screening clinic should contact the co-ordinator to inform them of the need for a referral. The co-ordinator of the local programme should then make the referral within one working day of the clinic, to the appropriate vascular unit (see below).

A letter should be sent to the subject and the GP along with a summary of previous screening results. The referral letter should be sent directly to the secretary of the appropriate vascular surgeon or vascular centre. Local process should dictate the quickest and most effective way of making this referral. The local service co-ordinator should verify the referral has been received and acted upon.

At the same time the GP practice should be informed in writing, with a follow-up phone call to ensure the practice is aware of the referral. As the referral is based on the ultrasound measurement alone, the GP may want to provide additional information to the surgeon. The subject and/or GP may choose to alter the referral location (within 5 working days of contact with the practice). The GP should be asked to send any additional information, special requests or exclusions to the co-ordinator who will record this information and pass it on to the appropriate clinician. Any change to the referral should also be logged on to the SMaRT system.

All referrals should be seen in the vascular outpatients department within 2 weeks of the scan. If the AAA has a diameter on ultrasound of over 7cm, an urgent referral should be made with every attempt to see the patient at the next available outpatient clinic.

The choice of vascular surgeon from those eligible (fulfilling the NVR audit requirements and nominated as part of the screening programme) will be made by the local screening programme.

The GP and patient should be made aware in writing that:

• strong links between screening services and vascular networks help to ensure that surgery is of a consistently high standard
• it may not be possible to verify high quality surgical outcomes from vascular surgeons not participating in the screening programme
• the screening programme will not learn the outcome of a referral to a vascular surgeon not participating in the programme. This will make it more difficult to ensure that appropriate follow-up takes place

On referral to the vascular unit:

• if a repeat imaging test show the AAA to be less than 5.5cm in diameter, or the patient is unfit for surgery, continued follow-up should be arranged under the care of the vascular surgeon (not the screening programme). Once a patient has been under the care of the vascular surgeon due to a referral or for surveillance they must not be referred back to the screening programme for them to monitor
• the screening office should be advised by letter of the outcome and results of each consultation

8. Treatment and intervention

The vascular unit undertaking surgical treatment should consider the guidelines of the VSGBI. The vascular unit is responsible for setting up mechanisms with the local screening programme to inform the screening office of the decisions concerning surgery and the outcome of surgery.

Details of all AAA surgery performed by the vascular unit should be entered on to the National Vascular Registry by the vascular surgeon using the subjects NHS number and made available to the screening office though the interface across the national IT system (the NHS number must be entered to allow the records to be linked automatically).

9. End of the pathway

Active inclusion in the screening programme ends when:

• the scan is found to be within normal limits (aorta less than 3cm diameter (inner to inner) on AP measurement in both longitudinal and transverse view, at initial scan)
• the AAA reaches 5.5cm diameter on ultrasound on either of the AP measurements and the subject has been referred to the vascular unit. It is the responsibility of the screening programme to ensure the referral has successfully reached the vascular service and been acted upon. Note that a diagnosis is not made at the completion of a screening test. The ‘diagnosis’ of an AAA will be made by the vascular surgeon
• the director of the local screening programme or the GP decides referral for treatment should be considered based on other factors (for example, symptoms or co-morbidities)
• after 3 consecutive scans showing an aortic diameter less than 3cm on ultrasound where the initial scan was 3cm or greater. In this case the man should be discharged from the screening programme and both the man and GP informed by letter
• after 15 scans at one-year intervals the AAA remains below 4.5cm. In this case the man should be discharged from the screening programme and both the man and GP informed by letter
• if the man declines to be in the screening programme, fails to attend consecutive appointments as per local policy, moves out of the area and becomes the responsibility of another screening programme (if one exists) or dies. If a man under surveillance moves out of the area, the co-ordinator should alert the screening programme responsible for the GP practice to which the patient is then registered

Patients who have had AAA identified through routes outside the screening programme must not be referred to the screening programme for surveillance except for Inclusions listed in this document. These patients must stay within the care of the vascular service.

10. Self-referral process

Men aged over 65 who have not been screened previously may contact the programme asking for a screening appointment. These men are known as self-referrals. Men should only be accepted as a self-referral by the local programme if they are registered with a GP practice covered by that programme. There is a national letter template that can be sent to men who are not registered with a GP.

An NHS number will be required for all men who enter the screening programme and it is likely some men will not know their individual number. A local process must be established which enables the screening programme to access this important piece of information. The self-referral proforma (ADD LINK) can be used for this purpose.

11. Screening flowcharts

The NHS AAA Screening programme has developed a care pathway.