title: Relationship between abdominal aortic aneurysm wall compliance and clinical outcome: a preliminary analysis.
abstract: BACKGROUND
  Aortic compliance, as measured by the pressure-strain elastic modulus (Ep) and stiffness (B), may allow a more precise estimate of abdominal aortic aneurysm rupture risk than size alone.
  
  
  OBJECTIVE
  To determine the relationships between AAA compliance, size, growth, and clinical outcome.
  
  
  METHODS
  One-hundred and twelve patients with initially non-operated AAA (86 men, 26 women, mean age 73 years), recruited from five centres, underwent baseline compliance measurements and were then followed for a median of 7 (range 2-18) months; 85 patients underwent repeated measurements (median 3, range 2-5) 3-6-monthly over a median of 12 (range 3-18 months).
  
  
  RESULTS
  Seven patients have ruptured and 16 have undergone repair of non-ruptured AAA. AAA that ruptured had significantly lower Ep and B (more compliant). In AAA that ruptured or required repair there was an inverse relationship between diameter and Ep and B. In those undergoing repeated measurements AAA expansion was only associated with a significant increase in Ep and B in non-operated patients.
  
  
  CONCLUSIONS
  Baseline AAA compliance was significantly related to rupture and the future requirement for operative repair. Failure of compliance to increase with size may be a marker for rapid growth, developmental symptoms and rupture.
authors.affiliation: Vascular Surgery Unit, University of Edinburgh, Royal Infirmary, U.K.
authors.forename: K
authors.initials: K
authors.lastname: Wilson
authors.forename: A
authors.initials: A
authors.lastname: Bradbury
authors.forename: M
authors.initials: M
authors.lastname: Whyman
authors.forename: P
authors.initials: P
authors.lastname: Hoskins
authors.forename: A
authors.initials: A
authors.lastname: Lee
authors.forename: G
authors.initials: G
authors.lastname: Fowkes
authors.forename: P
authors.initials: P
authors.lastname: McCollum
authors.forename: C V
authors.initials: CV
authors.lastname: Ruckley
mesh_terms: D000368:Aged; D017544:Aortic Aneurysm, Abdominal / Q000473:pathology / Q000503:physiopathology* / Q000601:surgery; D001019:Aortic Rupture / Q000209:etiology* / Q000503:physiopathology / Q000601:surgery; D001794:Blood Pressure; D003187:Compliance; D004548:Elasticity; D005260:Female; D005500:Follow-Up Studies; D005544:Forecasting; D006801:Humans; D008297:Male; D012307:Risk Factors; D013314:Stress, Mechanical; D016896:Treatment Outcome