title: Optimal interval screening and surveillance of abdominal aortic aneurysms.
abstract: OBJECTIVE
  to determine safe and optimal intervals of rescreening and surveillance for AAA.
  
  
  METHODS
  hospital-based mass screening of 6339 65-73-year-old men from 1994-98. 76.4% attended. One hundred and ninety-one (4%) had AAA53 cm. Twenty-four (0.5%) were initially >5 cm and referred for surgery, while the rest were offered annual control scans to check for expansion. Later, all 348 (7.5%) men who 3 to 5 years ago had an ectatic aorta (infrarenal aortic diameter of 25-29 mm or distal/renal aortic diameter ratio >1.2) were offered rescreening. Of these, 62 (18%) died before rescanning, while 248 of the survivors attended rescreening (87%). Furthermore, a random sample of 380 of those with non-ectatic aortas were offered rescreening. Of these, 49 (13%) died before rescreening (p=0.06), while 275 (83%) of the survivors attended re-screening.
  
  
  RESULTS
  none of the controls had developed AAA. Of those who initially had an 25-29 mm aorta, 29% had developed AAA (size range 30-48 mm) with expansion rates varying from 1.0 to 4.7 mm/year. Only 3.5% with a ratio >1.2 developed AAA (size range: 30-34 mm) with expansion rates from 1.3 to 2.4 mm/year. During the fourth year of surveillance some AAA initially sized below 3.5 cm expanded to above 5 cm, while some sized 3.5-3.9 cm did so during the second year, >4 cm did so during the first year of surveillance.
  
  
  CONCLUSIONS
  rescreening for AAA can be restricted to initially ectatic aortas sized 25-29 mm at 5-year intervals. Surveillance of small AAA can be restricted to 1-4 year intervals.
authors.affiliation: Department of Vascular Surgery, Viborg Hospital, Denmark.
authors.forename: J S
authors.initials: JS
authors.lastname: Lindholt
authors.forename: S
authors.initials: S
authors.lastname: Vammen
authors.forename: S
authors.initials: S
authors.lastname: Juul
authors.forename: H
authors.initials: H
authors.lastname: Fasting
authors.forename: E W
authors.initials: EW
authors.lastname: Henneberg
mesh_terms: D017677:Age Distribution; D000368:Aged; D017544:Aortic Aneurysm, Abdominal / Q000175:diagnosis* / Q000401:mortality*; D006801:Humans; D015994:Incidence; D008297:Male; D008403:Mass Screening / Q000379:methods*; D011159:Population Surveillance; D011446:Prospective Studies; D012307:Risk Factors; D012680:Sensitivity and Specificity; D016019:Survival Analysis; D013997:Time Factors