Aortic aneurysm screening: a personal history

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My first significant contact with abdominal aortic aneurysm (AAA) screening was when I was appointed as a consultant surgeon in Gloucestershire in 1991. My consultant colleague, Brian Heather, had already started an AAA screening programme for 65-year-old men in Gloucestershire. The burden of managing vascular disease single-handed for a population of 350,000 was significant for him; in addition, patients with ruptured AAA were major consumers of critical care services in Gloucestershire at the time. Brian contacted all the GP surgeries in Gloucestershire asking whether (i) they were prepared to identify the 65-year-old men in their practice each year, and then (ii) to receive a visit once a year for them to be scanned. He secured the services of a research nurse, Elaine Shaw, who took a portable ultrasound scanner to the GP surgeries to do the scans. The screening programme in Gloucestershire was born in 1988 and has run ever since1.

The underlying method of screening 65-year-old men developed in Gloucestershire has been copied worldwide. Since in Gloucester at the time most 65-year-old men had just retired, with nothing else to do, so Brian thought inviting them then would maximize attendance. There have been several papers published on the Gloucestershire Aneurysm Screening Programme, the last of which reviewed the first 25 years, and documented the fascinating observation that the average aortic diameter in 65-year-old men reduced by 12%, in both smokers and non-smokers2.

After Alan Scott had conducted the seminal RCT on screening for AAA, the MASS trial, there was a discussion with the National Screening Committee (NSC) about whether this should be a national programme. The NSC Director at the time was Muir Gray, who was very enthusiastic and commissioned an NSC review which confirmed it should be cost effective, and recommended population screening for AAA in men in the UK. At the time I was Honorary Secretary of the Vascular Society of Great Britain and Ireland. I recall the Society being given the opportunity to present the data on AAA screening to the then Secretary of State for Health. We only had five minutes, because she was busy, but I remember presenting just five slides in one of the committee rooms of the Houses of Parliament. We were delighted when funding was agreed for what became the NHS AAA Screening Programme (NAAASP). In retrospect, I think we were just timely in that funding was available as part of the Gordon Brown government’s national health checks initiative.

In a quirk of fate, I didn't see the subsequent application for the job of Clinical Lead for NAAASP, but as Secretary of the Vascular Society I was asked to review the applicants. I cheekily asked whether it be possible to apply for the job, rather than help choose the candidate. I was allowed to make a belated application, which proved to be successful.

There were then two years of hard graft trying to develop the nuts and bolts of the Programme and all the technical details and failsafes. It was worth it, because the Programme standards have stood the test of time. A committee was formed to run the programmes called the Four Nations Group to harmonize AAA screening in Scotland, Wales, Northern Ireland and England. For me, keeping this group together and using the same methods in the different nations was one of the most important aspects of NAAASP, and allowed analysis of results across the UK. The Programme commenced rollout in 2009, and by 2013 all men aged 65 in the UK each year were invited for an aortic ultrasound.

In 2019, I retired as Clinical Lead for NAAASP, but was delighted to be invited to be part of the team conducting the effectiveness review of the first 10 years in 2024. The full effectiveness review is published on the gov.uk site and a summary is published in the May BJS3. It was gratifying to find that the Programme is running efficiently, a great tribute to all those who designed it and continue to deliver the service. Over 3.5 million men have been invited for screening, and thousands of aneurysms detected, many of which have required surgical treatment to prevent rupture. The interesting paradox is that the prevalence of AAA has been reducing quickly over the decade; indeed death rates from ruptured AAA reduced by around 50%, even in men who were not scanned. In the age group that were potentially scanned, the reduction in death rates is nearly three quarters, demonstrating the additional effect of screening. It is estimated that several hundred men avoided death from ruptured AAA as a result of the NAAASP.

The ongoing reduction in the prevalence of AAA suggests there will be a time in the next decade or so when population screening ceases to be cost-effective. Perhaps the most interesting part of the review is to discuss what should happen next. The options are ceasing AAA screening, or modifying it. Since there will be around 15,000 men with small and medium aneurysms who will still need ultrasound surveillance, modifying the programme seems most sensible. The most likely outcome will be a form of targeted screening, whereby men, and possibly women, in high risk groups will be invited using the same programme structure and the same team of dedicated screeners who have proved so effective. There is a real opportunity for those with an interest in AAA screening to conduct research over the next decade which will focus on the optimal way of continuing a screening and surveillance programme.

It has been a privilege to bookend my career with the effectiveness review of aneurysm screening. It has been a fascinating opportunity to see how a screening programme could be developed from scratch, and then modified whilst it is ongoing. It's also been extraordinary to see the changes in vascular biology going on within the male aorta and presumably also going on within all their other arteries. I wish all those who now take forward the organization and management of aneurysm screening the very best for the future.