Tools for Practice


#75 Screening for Abdominal Aortic Aneurysm: None, Some or All?


CLINICAL QUESTION
Does screening asymptomatic patients in primary care for abdominal aortic aneurysm (AAA) alter mortality?

BOTTOM LINE
Recommended ultrasound screening of men aged 65-74 for AAA can prevent 1 AAA-related death in 238 screened after 10 years, but does not change all-cause mortality. Population-based screening is not indicated for women.


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EVIDENCE
Men: 
  • MASS study:1 High-quality randomized controlled trial (RCT) of 67,800 asymptomatic primary care British men aged 65-74 years randomized to invitation to 1-time screening with abdominal ultrasound versus no invitation 
    • Prevalence of AAA (>3 cm)=4.9% 
    • After 10 years of follow-up:2 
      • AAA-related mortality: 4.6/1000 deaths with screening versus 8.7/1000 without 
        • Number needed to screen (NNS)=238 to prevent 1 AAA-related death at 10 years. 
Women: 
  • One RCT subgroup3 of 9342 asymptomatic primary care British women aged 65-80 years randomized to invitation to screening with ultrasound versus no invitation 
    • Prevalence of AAA = 1.3% 
    • After 30 months of follow-up: 
      • No difference in AAA rupture or deaths, or all-cause mortality. 
Systematic reviews4,5 of 4 RCTs (MASS was ~50% of patients): 
  • No difference in all-cause mortality (men or women) 
  • AAA-related mortality decreased only in men. 
Context:  
  • AAA risk factors, odds ratios:6  
    • Major: Male=5.7, smoking=3 per 10 pack-years, family history of AAA=3.8, age=2.8 per 5-year increase over 55,  
    • Minor: Concurrent atherosclerotic disease~1.5, dyslipidemia=1.3, hypertension=1.25, BMI >25=1.2. 
  • Annual risk of rupture according to maximum diameter of aneurysm:7 
    • <4 cm = 0.5%, 4-4.9 cm = 1%, 5-5.9 = 11%, 6-6.9 cm = 26% 
  • Guideline recommendations: 
    • Canada:7 
      • Men: Screening ultrasound if 65-75 years (if reasonable surgical candidate) 
      • Women: No routine screening 
        • Individualized screening if >65 years and multiple risk factors 
    • United States:8 
      • Men: 1-time screening ultrasound for current or previous smokers 65-75 years old 
        • Consider selectively screening non-smoking males 65-75 years with other risk factors 
      • Women: No routine screening. 
  • Abdominal palpation (accuracy):9 
    • 50% sensitivity for AAA 4-4.9 cm. 
updated aug 5 2016 by ricky
October 15, 2012

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Author(s):

  • Ian C Taylor MD
  • Michael R Kolber MD CCFP MSc
  • Robert G Turnbull MD FRCSC

1. The Multicentre Aneurysm Screening Study Group. Lancet 2002;360:1531-9.

2. Thompson SG, Ashton HA, Gao L, et al. BMJ 2009;338:b2307.

3. Scott RAP, Bridgewater SG, Ashton HA. Br J Surg 2002;89:283-5.

4. Cosford PA, Leng GC, Thomas J. Cochrane Database Syst Rev 2011;2:CD002945.

5. Guirguis-Blake JM, Beil TL, Senger CA, Whitlock EP. Ann Intern Med 2014;160:321-9.

6. J Vasc Surg 2010;52:539-48.

7. Mastracci TM, Cina CS. J Vasc Surg 2007;45:1268-76.

8. US Preventive Services Task Force. Ann Intern Med 2014;161:281-90.

9. Lederle FA, Simel DL. JAMA 1999;281:77-82.

Authors do not have any conflicts of interest to declare.