title: Risk of rupture in unruptured anterior communicating artery aneurysms: meta-analysis of natural history studies.
abstract: BACKGROUND
  The decision of whether to operate on patients bearing UIAs is complicated by the limitations in current knowledge of the natural history of such lesions. The ISUIA has estimated the annual risk of rupture below that justifying surgery for most incidentally found lesions less than 7 mm in diameter. However, there is some evidence that aneurysms located in the ACoA show a higher risk of rupture, even with diameters of less than 7 mm. The present study was conducted to investigate the risk of aneurysm rupture in this site.
  
  
  METHODS
  The available literature on the subject was thoroughly reviewed, and a meta-analysis was carried out comparing the risk of rupture of aneurysms found in the ACoA with that of aneurysms in other sites.
  
  
  RESULTS
  Aneurysms found unruptured in the ACoA show a risk of rupture twice as high as that of other intracranial aneurysms (95% confidence interval, 1.29-3.12). It is the first time this fact has been demonstrated based on the follow-up of unruptured aneurysms.
  
  
  CONCLUSIONS
  When deciding whether to operate on UIAs located in the ACoA, surgeons should consider their higher risk of rupture.
authors.affiliation: Departamento de Neurocirurgia, Hospital Santa Casa de Misericórdia, Santana do Livramento, Rio Grande do Sul, Brazil. juanmira@ig.com.br <juanmira@ig.com.br>
authors.forename: Juan Marcos Suárez
authors.initials: JM
authors.lastname: Mira
authors.forename: Fernando Antonio De Oliveira
authors.initials: FA
authors.lastname: Costa
authors.forename: Bernardo Lessa
authors.initials: BL
authors.lastname: Horta
authors.forename: Othello Moreira
authors.initials: OM
authors.lastname: Fabião
mesh_terms: D017542:Aneurysm, Ruptured / Q000209:etiology*; D006801:Humans; D002532:Intracranial Aneurysm / Q000150:complications* / Q000473:pathology; D018570:Risk Assessment