Abdominal aortic aneurysm screening: current effectiveness and future perspectives

Abdominal aortic aneurysm (AAA) is a degenerative condition of the abdominal aorta that results in its progressive dilatation with an eventual risk of fatal rupture. AAAs are most common in elderly men, particularly those who are cigarette smokers1. There are also genetic factors increasing the risk within families2,3. In the 1980s and 1990s, there was a spike in prevalence of AAA in many high-income countries in Europe and North America, where death rates from ruptured AAA (rAAA) started to increase, most likely as a consequence of population smoking habits 20 years earlier4. During this time, managing rAAA was an increasing problem for the emerging surgical specialty of vascular surgery, and a significant drain on critical care bed resources. AAA fulfils many of the WHO criteria for screening: potentially fatal condition, long gestation, simple and safe screening test, established and effective procedure to prevent rupture5. In the 1990s, there were several RCTs of population screening for AAA in men. The largest, the MASS (Multicentre Aneurysm Screening Study) trial, showed that invitation for a single ultrasound scan in men aged 65 reduced mortality from ruptured AAA by 42.0% (53.0% in those who attended), and was cost-effective for a publicly funded health service6,7. A systematic review of all the RCTs of AAA screening after 10 years concluded there was also a small but significant reduction of overall mortality rate in men who were invited for screening8. In the UK a formal population screening programme for AAA in men was recommended in 2005 after the UK National Screening Committee (UKNSC) reviewed the scientific evidence, and the programme was commissioned by the NHS in 20099. National coverage was achieved by 2013. A similar population screening programme was funded in Sweden that achieved national coverage in 201510. Many other countries developed AAA screening in men using different models11. It should be noted that screening was introduced despite the fact that the prevalence of AAA had started to fall, based on the strong scientific evidence that was available at the time. Other countries took the view that as the prevalence was falling anyway, AAA screening was not a health priority.