title: Comparison of outcomes after aortic valve replacement with a mechanical valve or a bioprosthesis using microsimulation.
abstract: BACKGROUND
  Mechanical valves and bioprostheses are widely used for aortic valve replacement. Though previous randomised studies indicate that there is no important difference in outcome after implantation with either type of valve, knowledge of outcomes after aortic valve replacement is incomplete.
  
  
  OBJECTIVE
  To predict age and sex specific outcomes of patients after aortic valve replacement with bileaflet mechanical valves and stented porcine bioprostheses, and to provide evidence based support for the choice of prosthesis.
  
  
  METHODS
  Meta-analysis of published results of primary aortic valve replacement with bileaflet mechanical prostheses (nine reports, 4274 patients, and 25,726 patient-years) and stented porcine bioprostheses (13 reports, 9007 patients, and 54,151 patient-years) was used to estimate the annual risks of postoperative valve related events and their outcomes. These estimates were entered into a microsimulation model, which was employed to calculate age and sex specific outcomes after aortic valve replacement.
  
  
  RESULTS
  Life expectancy (LE) and event-free life expectancy (EFLE) for a 65 year old man after implantation with a mechanical valve or a bioprosthesis were 10.4 and 10.7 years and 7.7 and 8.4 years, respectively. The lifetime risk of at least one valve related event for a mechanical valve was 48%, and for a bioprosthesis, 44%. For LE and EFLE, the age crossover point between the two valve types was 59 and 60 years, respectively.
  
  
  CONCLUSIONS
  Meta-analysis based microsimulation provides insight into the long term outcome after aortic valve replacement and suggests that the currently recommended age threshold for implanting a bioprosthesis could be lowered further.
authors.affiliation: Department of Cardiothoracic Surgery, Room Bd 162a, Erasmus MC, Rotterdam, Netherlands. j.p.a.puvimanasinghe@erasmusmc.nl
authors.forename: J P A
authors.initials: JP
authors.lastname: Puvimanasinghe
authors.forename: J J M
authors.initials: JJ
authors.lastname: Takkenberg
authors.forename: M B
authors.initials: MB
authors.lastname: Edwards
authors.forename: M J C
authors.initials: MJ
authors.lastname: Eijkemans
authors.forename: E W
authors.initials: EW
authors.lastname: Steyerberg
authors.forename: L A
authors.initials: LA
authors.lastname: Van Herwerden
authors.forename: K M
authors.initials: KM
authors.lastname: Taylor
authors.forename: G L
authors.initials: GL
authors.lastname: Grunkemeier
authors.forename: J D F
authors.initials: JD
authors.lastname: Habbema
authors.forename: A J J C
authors.initials: AJ
authors.lastname: Bogers
mesh_terms: D000368:Aged; D000818:Animals; D001021:Aortic Valve / Q000601:surgery*; D001022:Aortic Valve Insufficiency / Q000601:surgery; D001705:Bioprosthesis; D003198:Computer Simulation; D005260:Female; D006350:Heart Valve Prosthesis; D019918:Heart Valve Prosthesis Implantation / Q000401:mortality; D006801:Humans; D008297:Male; D008875:Middle Aged; D015607:Stents; D013552:Swine; D016896:Treatment Outcome