Ultrasound screening for abdominal aortic aneurysm: current practice, challenges and controversies

Abstract

The UK screening programme began in 2009, and has now been expanded around the UK. Long-term follow-up of the original cohorts continues to demonstrate significant benefits for abdominal aortic aneurysm (AAA)-related and all-cause mortality , and results from the first 5 years of the formal screening programme have demonstrated similar success. Ultrasound scanning is an effective and safe screening tool for the detection of AAA, although a variety of measurement protocols are employed internationally. Key challenges for the future of the programme relate to declining incidence of screen detected aneurysms. Recent publications have demonstrated a UK incidence of only 1.34%, compared to 4.9-7.2% of men invited for screening in the original trials. Work into increasing engagement amongst the target group, and expanding screening to siblings and women is underway to address this issue. This review describes the evidence behind the screening programme, its justification in addressing AAA as a significant health problem and discusses some of the potential developments in the future.

Figure 1.

A transverse image of an AAA from Hartshorne et al demonstrating the inner to inner measurement used in the NAAASP. The aortic diameter is measured in the anteroposterior plane. The straight arrows indicate the position of the inner anterior and inner posterior wall. The angle arrows indicate the position of the outer anterior and outer posterior wall. The asterisk indicates an area of mural thrombus on the posterior wall. The authors have shown this to demonstrate the importance of not placing the posterior inner wall calliper on the inner border of the thrombus. AAA, abdominal aortic aneurysm; NAAASP, national abdominal aortic aneurysm screening programme.

Figure 2.

Techniques used for repair of infra-renal AAA. (a) Open repair. Once inflow and outflow are controlled the aneurysm sac is opened and a synthetic graft is sutured in place onto normal aorta. (b) EVAR. A covered stent graft is inserted into the AAA via the common femoral arteries and is anchored to the normal aorta above the aneurysm and in the iliac arteries below, either by radial force from the spring mounted fabric, or supra-renal fixating hooks. Newer generation stent grafts have also been introduced that use aortic sealing technology. AAA, abdominal aortic aneurysm; EVAR, endovascular aneurysm repair.