title: Does preservation of the sub-valvular apparatus during mitral valve replacement affect long-term survival and quality of life? A Microsimulation Study.
abstract: BACKGROUND
  Techniques to preserve the sub-valvular apparatus in order to reduce morbidity and mortality following mitral valve replacement have been frequently reported. However, it is uncertain what impact sub-valvular apparatus preservation techniques have on long-term outcomes following mitral valve replacement. This study investigated the effect of sub-valvular apparatus preservation on long-term survival and quality of life following mitral valve replacement.
  
  
  METHODS
  A microsimulation model was used to compare long-term survival and quality-adjusted life years following mitral valve replacement after conventional valve replacement and sub-valvular apparatus preservation. Probabilistic sensitivity analysis and alternative analysis were performed to investigate uncertainty associated with the results.
  
  
  RESULTS
  Our Analysis suggests that patients survive longer if the sub-valvular apparatus are preserved (65.7% SD 1.5%, compared with 58.1% SD 1.6% at 10 years). The quality adjusted life years gained over a 10 year period where also greater after sub-valvular apparatus preservation. (6.54 QALY SD 0.07 QALY, compared with 5.61 QALY, SD 0.07 QALY). The superiority of preservation techniques was insensitive to patient age, parameter or model uncertainty.
  
  
  CONCLUSIONS
  This study suggests that long-term outcomes may be improved when the sub-valvular apparatus are preserved. Given the lack of empirical data further research is needed to investigate health-related quality of life after mitral valve replacement, and to establish whether outcomes differ between preservation techniques.
authors.affiliation: Department Biosurgery and Surgical Technology, Imperial College London, London, UK. christopher.rao@imperial.ac.uk
authors.forename: Christopher
authors.initials: C
authors.lastname: Rao
authors.forename: Jonathan
authors.initials: J
authors.lastname: Hart
authors.forename: Andre
authors.initials: A
authors.lastname: Chow
authors.forename: Fotios
authors.initials: F
authors.lastname: Siannis
authors.forename: Polyxeni
authors.initials: P
authors.lastname: Tsalafouta
authors.forename: Bari
authors.initials: B
authors.lastname: Murtuza
authors.forename: Ara
authors.initials: A
authors.lastname: Darzi
authors.forename: Frank C
authors.initials: FC
authors.lastname: Wells
authors.forename: Thanos
authors.initials: T
authors.lastname: Athanasiou
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006349:Heart Valve Diseases / Q000401:mortality / Q000601:surgery*; D006350:Heart Valve Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve / Q000601:surgery*; D008955:Models, Cardiovascular; D009926:Organ Preservation / Q000379:methods* / Q000401:mortality; D011379:Prognosis; D011788:Quality of Life; D015203:Reproducibility of Results; D018570:Risk Assessment / Q000379:methods; D012680:Sensitivity and Specificity; D015996:Survival Rate / Q000639:trends