The NHS Abdominal Aortic Aneurysm Screening Programme (NAAASP) has been rolled out across England and increasing numbers of men will have to choose whether to undergo screening.
Men aged 65 and over will have to decide whether to be screened for abdominal aortic aneurysm (AAA), which accounts for about 2% of all deaths in this population group.
GPs should be aware of the NAAASP and will play an important part in helping patients to make informed choices by enabling them to access balanced information about the benefits and risks of screening.
Screening for AAA
An AAA occurs because of degeneration of the wall of the abdominal aorta. Large AAA are rare, but can be very serious; ruptured AAA accounts for about 5,000 deaths every year in England and Wales. Small AAA pose little immediate risk, but can expand, so it is essential to monitor them.
AAA are generally asymptomatic and seldom cause symptoms before rupture (which is usually fatal), so screening provides an opportunity for detection and surgical repair, once the risk of rupture exceeds the risk of treatment.
The screening process for AAA is a simple ultrasound scan and patients receive their results immediately. This ensures that men with a small AAA who require regular ultrasound surveillance are identified and offered advice on reducing cardiovascular risk factors. Their GP may be asked to review their medication and reassess their BP monitoring.
Antiplatelet and statin therapy is recommended for men with a small AAA and smoking cessation can reduce the rate of expansion, in addition to its other health benefits.
Other screening outcomes include a small number of men with an aorta of 5.5cm diameter or more, who are referred to a vascular surgery team. Most men who have no signs of an AAA are reassured.
The main risk factors for AAA are smoking, hypertension and a family history (first-degree relative with AAA). Men who are most likely to benefit from self-referral for screening are therefore those in their late 60s and early 70s who have one or more of these risk factors.
The NAAASP only screens men aged 65 and over. However, younger men, or women with a family history, can be scanned under existing NHS procedures.
GPs are recommended to consider referring patients with a sibling or parent with an AAA for a scan at the medical imaging department at an age five years younger than that at which their relative's AAA was first diagnosed.
Each GP practice is informed when a patient of theirs is screened, then updated with the results.
Patients may wish to discuss their screening results with their GP, so it is important that awareness of the programme is widespread in the primary care community.
GPs should expect more men to enquire about the programme and to consider self-referral if they missed out on an automatic invitation.
GPs may find themselves discussing the programme with patients more often, but should be reassured that every stage of the screening pathway is designed to keep primary care workload to a minimum.
Benefits and risks
Despite only just completing national roll-out, the programme has already delivered promising results. NAAASP data for 2012-13 show that 209,000 men were screened for the first time during the year, with 77% of those invited actually attending.
More than 3,000 aneurysms were detected. While most were small and will need regular monitoring, a few patients were referred to vascular surgeons to discuss possible treatment options.
More than 300 large aneurysms were detected by screening and treated during the year, and the programme is making progress towards its aim of reducing deaths from ruptured AAA among men aged 65 and over by up to 50%.
In addition to delivering clinical benefits, the NAAASP has been assessed by the UK National Screening Committee as delivering value for money to the NHS.
There are, however, risks associated with AAA treatment, which are clearly communicated to men when they are invited for screening.
If a large AAA is detected or develops, intervention carries risk - the mortality rate following elective AAA repair is about 2%.
The NAAASP provides a range of materials to help GPs who are involved in a discussion with men or their relatives about screening, which can be found on the NAAASP website (see Resources, below).
Explaining the benefits and risks of screening can be challenging, but is an important role for GPs.
- Mr Earnshaw is the national director of the NAAASP and a vascular surgeon, Gloucestershire Hospitals NHS Foundation Trust
- The NAAASP is run by the UK National Screening Committee and operates separately from the Vascular Risk Management Programme
- For more information, visit the NAAASP website at aaa.screening.nhs.uk
- For further materials on private screening, visit the UK Screening Portal website at www.screening.nhs.uk/private-screening