title: Survival following ruptured abdominal aortic aneurysm before and during the IMPROVE Trial: a single-centre series.
abstract: OBJECTIVE
  The first large-scale randomised trial (Immediate Management of the Patient with Rupture: Open Versus Endovascular repair [IMPROVE]) for endovascular repair of ruptured abdominal aortic aneurysm (rEVAR) has recently finished recruiting patients. The aim of this study was to examine the impact on survival after rEVAR when the IMPROVE protocol was initiated in a high volume abdominal aortic aneurysm (AAA) centre previously performing rEVAR.
  
  
  METHODS
  One hundred and sixty-nine patients requiring emergency infrarenal AAA repair from January 2006 to April 2013 were included. Eighty-four patients were treated before (38 rEVAR, 46 open) and 85 (31 rEVAR, 54 open) were treated during the trial period. A retrospective analysis was performed.
  
  
  RESULTS
  Before the trial, there was a significant survival benefit for rEVAR over open repair (90-day mortality 13% vs. 30%, p = .04, difference remained significant up to 2 years postoperatively). This survival benefit was lost after starting randomisation (90-day mortality 35% vs. 33%, p = .93). There was an increase in overall 30-day mortality from 15% to 31% (p = .02), while there was no change for open repair (p = .438). There was a significant decrease in general anaesthetic use (p = .002) for patients treated during the trial. Randomised patients had shorter hospital and intensive treatment unit stays (p = .006 and p = .03 respectively).
  
  
  CONCLUSIONS
  The change in survival seen during the IMROVE trial highlights the need for randomised rather than cohort data to eliminate selection bias. These results from a single centre reinforce those recently reported in IMPROVE.
authors.affiliation: Department of Vascular Surgery, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK. Electronic address: Graeme.ambler@gmail.com.
authors.forename: G K
authors.initials: GK
authors.lastname: Ambler
authors.affiliation: Department of Vascular Surgery, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK.
authors.forename: C P
authors.initials: CP
authors.lastname: Twine
authors.affiliation: Department of Vascular Surgery, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK.
authors.forename: J
authors.initials: J
authors.lastname: Shak
authors.affiliation: Department of Vascular Surgery, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK.
authors.forename: K E
authors.initials: KE
authors.lastname: Rollins
authors.affiliation: Department of Vascular Surgery, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK.
authors.forename: K
authors.initials: K
authors.lastname: Varty
authors.affiliation: Department of Vascular Surgery, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK.
authors.forename: P A
authors.initials: PA
authors.lastname: Coughlin
authors.affiliation: Department of Vascular Surgery, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK.
authors.forename: P D
authors.initials: PD
authors.lastname: Hayes
authors.affiliation: Department of Vascular Surgery, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK.
authors.forename: J R
authors.initials: JR
authors.lastname: Boyle
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D017544:Aortic Aneurysm, Abdominal / Q000401:mortality* / Q000601:surgery*; D001019:Aortic Rupture / Q000401:mortality* / Q000601:surgery*; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D008297:Male; D008875:Middle Aged; D016896:Treatment Outcome; D014656:Vascular Surgical Procedures / Q000379:methods
keywords: Abdominal aortic aneurysm; Selection bias; Survival analysis