title: Ruptured abdominal aortic aneurysm: a novel method of outcome prediction using neural network technology.
abstract: BACKGROUND
  reported survival following emergency surgery for ruptured abdominal aortic aneurysm (RAAA) varies widely between institutions. This is largely attributable to differences in case mix. The aim of this study was to identify and evaluate a set of prognostic variables that would accurately predict outcome for individual patients from perioperative indices.
  
  
  METHODS
  perioperative factors associated with subsequent mortality at our institution were identified by retrospective review of 102 consecutive operations for RAAA over a 7-year period (January 1990 to January 1997). Logistic regression analysis was used to select the most significant variables associated with subsequent mortality. These were used to construct, train, and validate a neural network designed to predict survival from surgery in individual cases on a prospective basis.
  
  
  RESULTS
  the 30-day mortality rate was 53%. Multivariate analysis identified four highly significant independent predictors of mortality; preoperative hypotension, intraperitoneal rupture, preoperative coagulopathy, and preoperative cardiac arrest. Using these inputs, the neural network correctly predicted outcome in 82.5% of individual cases.
  
  
  CONCLUSIONS
  a neural network based on just four perioperative variables can accurately predict outcome of RAAA. Prognostic variables should be reported in studies as a measure of the effect of case mix on survival data. Neural networks have potential to aid decision-making relating to outcome for individual cases.
authors.affiliation: Departments of Vascular and Endovascular Surgery, St James's University Hospital, Leeds, LS9 7TF, U.K.
authors.forename: E P
authors.initials: EP
authors.lastname: Turton
authors.forename: D J
authors.initials: DJ
authors.lastname: Scott
authors.forename: M
authors.initials: M
authors.lastname: Delbridge
authors.forename: S
authors.initials: S
authors.lastname: Snowden
authors.forename: R C
authors.initials: RC
authors.lastname: Kester
mesh_terms: D000368:Aged; D017542:Aneurysm, Ruptured / Q000401:mortality* / Q000601:surgery*; D017544:Aortic Aneurysm, Abdominal / Q000401:mortality* / Q000601:surgery*; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D016571:Neural Networks, Computer; D011237:Predictive Value of Tests; D011379:Prognosis; D012189:Retrospective Studies; D012307:Risk Factors; D012680:Sensitivity and Specificity; D016019:Survival Analysis; D016896:Treatment Outcome