title: Systematic Review and Meta-analysis of Factors Influencing Survival Following Abdominal Aortic Aneurysm Repair.
abstract: BACKGROUND
  Predicting long-term survival following repair is essential to clinical decision making when offering abdominal aortic aneurysm (AAA) treatment. A systematic review and a meta-analysis of pre-operative non-modifiable prognostic risk factors influencing patient survival following elective open AAA repair (OAR) and endovascular aneurysm repair (EVAR) was performed.
  
  
  METHODS
  MEDLINE, Embase and Cochrane electronic databases were searched to identify all relevant articles reporting risk factors influencing long-term survival (≥1 year) following OAR and EVAR, published up to April 2015. Studies with <100 patients and those involving primarily ruptured AAA, complex repairs (supra celiac/renal clamp), and high risk patients were excluded. Primary risk factors were increasing age, sex, American Society of Anaesthesiologist (ASA) score, and comorbidities such as ischaemic heart disease (IHD), cardiac failure, hypertension, chronic obstructive pulmonary disease (COPD), renal impairment, cerebrovascular disease, peripheral vascular disease (PVD), and diabetes. Estimated risks were expressed as hazard ratio (HR).
  
  
  RESULTS
  A total of 5,749 study titles/abstracts were retrieved and 304 studies were thought to be relevant. The systematic review included 51 articles and the meta-analysis 45. End stage renal disease and COPD requiring supplementary oxygen had the worst long-term survival, HR 3.15 (95% CI 2.45-4.04) and HR 3.05 (95% CI 1.93-4.80) respectively. An increase in age was associated with HR of 1.05 (95% CI 1.04-1.06) for every one year increase and females had a worse survival than men HR 1.15 (95% CI 1.07-1.27). An increase in ASA score and the presence of IHD, cardiac failure, hypertension, COPD, renal impairment, cerebrovascular disease, PVD, and diabetes were also factors associated with poor long-term survival.
  
  
  CONCLUSIONS
  The result of this meta-analysis summarises and quantifies unmodifiable risk factors that influence late survival following AAA repair from the best available published evidence. The presence of these factors might assist in clinical decision making during discussion with patients regarding repair.
authors.affiliation: Department of Surgery, University of Otago, Christchurch, New Zealand; Department of Vascular Endovascular & Transplant Surgery Christchurch Hospital, New Zealand. Electronic address: manar.khashram@gmail.com.
authors.forename: M
authors.initials: M
authors.lastname: Khashram
authors.affiliation: Department of Population Health, University of Otago, Christchurch, New Zealand.
authors.forename: J A
authors.initials: JA
authors.lastname: Williman
authors.affiliation: Department of Population Health, University of Otago, Christchurch, New Zealand.
authors.forename: P N
authors.initials: PN
authors.lastname: Hider
authors.affiliation: Department of Surgical Sciences, Dunedin School of Medicine, University of Otago, 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 & Transplant Surgery Christchurch Hospital, New Zealand.
authors.forename: J A
authors.initials: JA
authors.lastname: Roake
mesh_terms: D000367:Age Factors; D017544:Aortic Aneurysm, Abdominal / Q000175:diagnosis / Q000401:mortality / Q000601:surgery*; D019917:Blood Vessel Prosthesis Implantation / Q000009:adverse effects / Q000401:mortality; D015897:Comorbidity; D017558:Elective Surgical Procedures; D057510:Endovascular Procedures / Q000009:adverse effects / Q000401:mortality; D005260:Female; D006801:Humans; D008297:Male; D015999:Multivariate Analysis; D016016:Proportional Hazards Models; D018570:Risk Assessment; D012307:Risk Factors; D012737:Sex Factors; D013997:Time Factors; D016896:Treatment Outcome
keywords: Abdominal aortic aneurysm; Endovascular aneurysm repair; Hazard rates; Survival factors; Systematic review