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ABDOMINAL AORTIC ANEURYSM SCREENING DR. KABILAN S JSR, CARDIOLOGY JIPMER

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AAA

• Definition – increase in size of abdominal aorta to > 3cm in diameter• MC form of aortic aneurysms• Incidence – 3.9% to 7.2% of men and 1.0% to 1.3% of women aged 50 years

or older • Prevalence - M > F• Strong association with cigarette smoking• 20 % familial• MC site of AAA – infrarenal aorta ( >80%)

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WHY TO SCREEN ?

• Primary risk associated with AAA – rupture (sudden & fatal) • The annual risk for rupture SIZE OF AAA ANNUAL RISK OF RUPTURE

3 – 3.9 cm 0%

4– 4.9 cm 1%

5 – 5.9 cm 11%

Guirguis-Blake JM et al. Ultrasonography screening for abdominal aortic aneurysms: a systematic evidence review for the U.S. Preventive Services Task Force. Ann Intern Med. 2014;160:321-9

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• 59% to 83% of patients with AAA rupture die before hospitalization• 40% - Operative mortality (in- hospital or 30-day) • 10% to 25% of persons with a ruptured AAA survive• Almost all deaths from rupture occur after 65 years of age• Most deaths in women occur after 80 years of age

Guirguis-Blake JM et al. Ultrasonography screening for abdominal aortic aneurysms: a systematic evidence review for the U.S. Preventive Services Task Force. Ann Intern Med. 2014;160:321-9

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AAA IMAGING MODALITIES

• Abdominal ultrasound- almost 100% sensitive & specific in detecting AAA• Abdominal CT – extremely accurate in both detection and measurement of

AAA• MRA – high accuracy in detection, measurement & planning repair of AAA• Screening of AAA- Ultrasound >> CT because of cost effectiveness,

avoidance of exposure to radiation & contrast• CT – preferred for AAA variants (inflammatory AAAs & mycotic aneurysms)

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RCT

S Svensjo et al. Eur J Vasc Endovasc Surg (2014) 48, 659

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• Meta analysis of the 4 RCTs 40 % reduction in AAA specific mortality in elderly men • 2.7 % reduction in all-cause mortality

Takagi H et al. The last judgment upon abdominal aortic aneurysm screening. Int J Cardiol 2013;167:2331e2

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MASS

• Multicenter aneurysm screening study• 46 deaths from AAA were prevented by screening 10,000 men• 217 men would have to be screened to prevent one death from AAA• Screening reduced the risk of AAA death by 42% • Number of elective AAA repairs conducted in the screening group

was twice that of the control group• Number of emergency repairs - halved

Ashton HA et al. The Multicentre Aneurysm Screening Study (MASS) into the effect of abdominal aortic aneurysm screening on mortality in men: a randomised controlled trial. Lancet 2002;360:1531

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ABDOMINAL ULTRASOUND SCREENING

• In MASS trial - inner to inner (ITI) wall measurement was used• In Gloucestershire trial - outer margin of the anterior wall to

the inner margin of the posterior wall (leading edge to leading edge (LELE) was measured • In Huntingdon screening trial - outer to outer diameter

(OTO) was used

111.Statistics Sweden. Retrieved December 2013 from www.scb.se 2.Anjum A et al. Explaining the decrease in mortality from abdominal aortic aneurysm rupture. Br J Surg 2012;99:637

• Reduced smoking rates seem to markedly coincide with falling rates of AAA prevalence 1

• Increased rates of elective AAA repair- reduction in overall AAA related mortality2

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ETHICS AND HARMS OF SCREENING

• The risk of death from elective repair- 1 in 10,000 men invited to screening• The risk of death following repair in incidentally detected

AAAs - higher than for screening detected AAAs• Mild transient reduction in quality of life

13Svensjo S et al. Screening for abdominal aortic aneurysm in 65-Year-old men remains cost-effective with contemporary epidemiology and management. Eur J Vasc Endovasc Surg 2014;47:357

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OTHER RECOMMENDATIONS• ACC & AHA - 1-time screening for AAA with physical examination and

ultrasonography in men aged 65 to 75 years who have ever smoked and in men aged 60 years or older who are the sibling or offspring of a person with AAA• These organizations do not recommend screening for AAA in men who have

never smoked or in women • Society for Vascular Surgery - 1-time ultrasonography screening for AAA in

men aged 55 years or older with a family history of AAA, all men aged 65 years or older, and women aged 65 years or older who have smoked or have a family history of AAA • American College of Preventive Medicine - 1-time screening in men aged

65 to 75 years who have ever smoked; it does not recommend routine screening in women

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• Canadian Society for Vascular Surgery - Ultrasonography screening for AAA in men aged 65 to 75 years who are candidates for surgery and willing to participate• In individualized cases, some women older than 65 years with multiple risk

factors (smoking history, cerebrovascular disease, or family history) may be considered for screening • European Society for Vascular Surgery - Men should be screened for AAA

with a single ultrasonography at age 65 years• Screening should be considered at an earlier age in men at higher risk (those

who smoke, have other cardiovascular disease, or have a family history)• Screening in older women - does not reduce the incidence of aneurysm rupture

but that screening women who smoke may require further investigation

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TAKE HOME MESSAGE

• AAA – most dreaded complication is rupture• Ultrasound- preferred modality for screening• AAA is strongly associated with smoking• Screening for AAA in elderly men and high risk women may be

beneficial for risk stratification for rupture risk• For serial monitoring and planning early repair• Cost effectiveness should be considered

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Thank you