title: The influence of incidental abdominal aortic aneurysm monitoring on patient outcomes.
abstract: BACKGROUND
  Incidental abdominal aortic aneurysms (AAAs) are identified when the abdomen is imaged for other reasons. These are common, and many undergo incomplete radiological monitoring. The association between monitoring completeness and population-based outcomes has not been studied.
  
  
  METHODS
  A cohort of incidental AAAs (defined as previously unidentified aortic enlargement exceeding 3 cm found on an imaging study done for another reason) was linked to population-based data. Patients were followed to elective AAA repair, AAA rupture, death, or March 31, 2009. Monitoring completeness was gauged as the sequential number of months without a recommended abdominal scan. Its association with time to elective AAA repair and time to death was measured using a multivariable Cox regression model adjusting for other important covariates.
  
  
  RESULTS
  We identified 191 incidental AAAs between 1996 and 2004 (median diameter of 3.5 cm [range, 3.0-5.3 cm], median follow up of 4.4 years [range, 0.6-12.7 years]). During the study, patients spent a median of 19.4% of their time with incomplete AAA monitoring (interquartile range [IQR] 0.3%-44%); 56 patients (29.3%) had no follow-up imaging of their aneurysm. Nineteen patients (10.0%; 2.0% per year) underwent elective AAA repair, and 79 patients (37.7%; 7.6% per year) died. Independent of important covariates, people were significantly less likely to undergo elective repair (hazard ratio [HR], 0.03) and significantly more likely to die (HR, 2.99) if their AAA went without radiological monitoring for 1 year.
  
  
  CONCLUSIONS
  Incomplete incidental AAA radiological monitoring was significantly associated with a decreased risk of elective AAA repair and an increased risk of death. While uncontrolled confounding might explain part of these associations, clinicians should ensure that radiological monitoring of AAAs is complete in appropriate patients.
authors.affiliation: Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada. carlv@ohri.ca
authors.forename: Carl
authors.initials: C
authors.lastname: van Walraven
authors.forename: Jenna
authors.initials: J
authors.lastname: Wong
authors.forename: Kareem
authors.initials: K
authors.lastname: Morant
authors.forename: Alison
authors.initials: A
authors.lastname: Jennings
authors.forename: Peter C
authors.initials: PC
authors.lastname: Austin
authors.forename: Prasad
authors.initials: P
authors.lastname: Jetty
authors.forename: Alan J
authors.initials: AJ
authors.lastname: Forster
mesh_terms: D000368:Aged; D001012:Aorta, Abdominal / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D017544:Aortic Aneurysm, Abdominal / Q000150:complications / Q000175:diagnosis* / Q000401:mortality / Q000601:surgery; D001019:Aortic Rupture / Q000209:etiology / Q000628:therapy; D001027:Aortography / Q000379:methods; D018450:Disease Progression; D017558:Elective Surgical Procedures; D005260:Female; D006801:Humans; D033162:Incidental Findings; D016015:Logistic Models; D008279:Magnetic Resonance Imaging; D008297:Male; D009864:Ontario; D018579:Patient Selection; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography; D014656:Vascular Surgical Procedures