Ultrasonographic screening for the detection of abdominal aortic aneurysms

Abstract

Background: The prevalence of abdominal aortic aneurysms (AAA) with a maximal diameter of 3 cm or more is age-dependent; among persons over age 65, it lies between 4% and 8% in men and between 0.5% and 1.5% in women. About 10% of all AAAs have a maximum diameter of 5 cm or more. The prognosis of ruptured AAA (rAAA) is dismal, with an overall mortality of at least 80%. Ultrasonography of the abdominal aorta is a safe and technically simple method of detecting AAAs.

Methods: Evaluation of population-based, randomized studies of ultrasonographic screening for the detection of AAA, based on a selective review of the literature.

Results: A meta-analysis of four randomized controlled studies showed that ultrasonographic screening was associated with a significant lowering of AAA-related mortality in men aged 65 to 80 after it had been performed for 3-5 years (risk reduction 44%, odds ratio [OR] 0.56, 95% confidence interval [CI] 0.44-0.72) and after it had been performed for 7-15 years (risk reduction 53%, OR 0.47, 95% CI 0.25-0.90). AAA screening was also associated with a significant lowering of the overall mortality after 7-15 years, but not in the first 5 years. Ultrasonographic screening led to a significant increase in the number of elective AAA operations performed and to a 50% reduction of the number of emergency operations for rAAA.

Conclusion: Ultrasonographic screening for AAA is a technically simple diagnostic test that is associated with a major reduction of AAA-related mortality. In view of the higher prevalence of AAA among the elderly, it is recommended that all men aged 65 or older and all men and women with a family history of AAA should be systematically screened. A national ultrasound screening program should be urgently implemented in Germany in order to bring about a major reduction in AAA-associated mortality.

Keywords: abdominal aortic aneurysm; aneurysm; aortic surgery; ultrasonographic diagnosis; vascular diagnosis.

Figure 1

Age-specific incidence of male and female inpatients with a main diagnosis of abdominal aortic aneurysm with or without rupture (I71.3, I71.4). (Source: Diagnostic data on all hospital patients 2007, German Federal Statistical Office)

Figure 2

Clinical risk factors for the development of an abdominal aortic aneurysm. Evaluation of eight different population-based studies including more than 110 000 probands (8)

Figure 3

Relationship between the diameter of an AAA and its annual risk of rupture

Figure 4

Open (a, b) and endovascular (c) treatment of an abdominal aortic aneurysm (Source: Vascular International Foundation, Pontresina Manual)

Figure 5

B-mode ultrasonogram of an abdominal aortic anuerysm in cross-section, showing the perfused lumen at the edge of the thrombus

Figure 6

Relative risk reduction from systematic ultrasound screening: meta-analysis of four randomized studies