The treatment for an abdominal aortic aneurysm (AAA) mostly depends on how big it is. AAAs are grouped into 3 sizes: small AAA – 3cm to 4.4cm across; medium AAA – 4.5cm to 5.4cm across; large AAA – 5.5cm or more across; Large AAAs are more likely to burst (rupture), so surgery to stop this happening is usually recommended.
https://www.nhs.uk/conditions/abdominal-aortic-aneurysm/treatment/

