title: Prevalence of abdominal aortic aneurysm (AAA) in a population undergoing computed tomography colonography in Canterbury, New Zealand.
abstract: OBJECTIVE
  There is compelling level 1 evidence in support of screening men for abdominal aortic aneurysm (AAA) to reduce AAA mortality. However, New Zealand (NZ) lacks data on AAA prevalence, and national screening has not been implemented. The aim of this study was to determine the prevalence of AAA in a population undergoing a computed tomography colonography (CTC) for gastrointestinal symptoms.
  
  
  METHODS
  This was an observational study; all consecutive CTCs performed in three regions of the South Island of NZ over a 4 year period were reviewed. Data on abdominal and thoracic aorta diameters ≥30 mm, and iliac and femoral aneurysms ≥20 mm were recorded. Previous aortic surgical grafts or endovascular stents were also documented. Demographics, survival, and AAA related outcomes were collected and used for analysis.
  
  
  RESULTS
  Included were 4,893 scans on 4,644 patients (1,933 men [41.6%], 2,711 women [58.4%]) with a median age of 69.3 years (range 17.0-97.0 years). There were 309 scans on 289 patients (75.4% men) who had either an aneurysm or a previous aortic graft with a median age of 79.6 years (range 57.0-96.0 years). Of these, 223 had a native AAA ≥30 mm. The prevalence of AAA rose with age from 1.3% in men aged 55-64 years, to 9.1% in 65-74 year olds, 16.8% in 75-84 year olds, and 22.0% in ≥85 year olds. The corresponding figures in women were 0.4%, 2%, 3.9%, and 6.2%, respectively.
  
  
  CONCLUSIONS
  In this observational study, the prevalence of AAA was high and warrants further evaluation. The results acquired help to define a population that may benefit from a national AAA screening programme.
authors.affiliation: Department of Surgery University of Otago, Christchurch, New Zealand. Electronic address: manar.khashram@gmail.com.
authors.forename: M
authors.initials: M
authors.lastname: Khashram
authors.affiliation: Department of Surgical Sciences, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand.
authors.forename: G T
authors.initials: GT
authors.lastname: Jones
authors.affiliation: Department of Surgery University of Otago, Christchurch, New Zealand; Department of Vascular Endovascular and Transplant Surgery, Christchurch Hospital, Christchurch, New Zealand.
authors.forename: J A
authors.initials: JA
authors.lastname: Roake
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D023881:Colonography, Computed Tomographic; D005260:Female; D006801:Humans; D033162:Incidental Findings; D008297:Male; D008875:Middle Aged; D009520:New Zealand / Q000453:epidemiology; D011237:Predictive Value of Tests; D015995:Prevalence; D012189:Retrospective Studies; D017678:Sex Distribution; D012737:Sex Factors; D055815:Young Adult
keywords: Abdominal aortic aneurysm; CT colonography; New Zealand; Prevalence; Screening