title: Subcoronary allograft aortic valve replacement: parametric risk-hazard outcome analysis to a minimum of 20 years.
abstract: BACKGROUND
  Differences in sterilization, preservation, and implantation have been implicated in aortic allograft longevity. We report follow-up to 30 years of patients from a single unit who underwent aortic valve replacement with aortic allografts sterilized in antibiotics and refrigerated at 4 degrees C.
  
  
  METHODS
  Two hundred consecutive patients underwent subcoronary allograft aortic valve replacement and have been followed up to a minimum of 20 and maximum of 30 years. Follow-up was 96% complete. Parametric hazard phase modeling was used to identify incremental predictors of time-related risk.
  
  
  RESULTS
  Early mortality was 1.5%. Kaplan-Meier actuarial survival, including early death, was 81.2% +/- 2.8% (mean +/- standard error of the mean), 58.0% +/- 3.7%, and 52% +/- 5.1% at 10, 20, and 25 years, respectively. Freedom from reoperation for any reason was 86.4% +/- 2.6%, 39.6% +/- 5.2%, and 35.0% +/- 5.4% at 10, 20, and 25 years, respectively. Larger implanted valve, reexploration for bleeding, previous cardiac surgery, and operative rank were independent risks for reoperation. Early mortality in reoperations was 5.1%. Allograft endocarditis has occurred in 6 patients, giving an overall freedom of 94% at 25 years. Seven patients of the original cohort are known to be alive with their original allograft valve in situ, and of these the longest follow-up period is 29.8 years.
  
  
  CONCLUSIONS
  The use of antibiotic-sterilized allografts for subcoronary aortic valve replacement confers low operative mortality and excellent long-term survival with durability matching any other nonmechanical device. Significantly reduced time-related risk of reoperation and excellent internal to external diameter ratio renders allograft aortic valve replacement especially ideal for smaller roots.
authors.affiliation: Wessex Cardiothoracic Centre, Southampton, United Kingdom. edward.hickey@sickkids.ca
authors.forename: Edward
authors.initials: E
authors.lastname: Hickey
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Langley
authors.forename: Oliver
authors.initials: O
authors.lastname: Allemby-Smith
authors.forename: Steven A
authors.initials: SA
authors.lastname: Livesey
authors.forename: James L
authors.initials: JL
authors.lastname: Monro
mesh_terms: D000293:Adolescent; D000328:Adult; D019072:Antibiotic Prophylaxis; D001021:Aortic Valve / Q000637:transplantation*; D002470:Cell Survival; D002648:Child; D004696:Endocarditis / Q000517:prevention & control; D005260:Female; D005500:Follow-Up Studies; D019918:Heart Valve Prosthesis Implantation / Q000009:adverse effects* / Q000401:mortality; D006801:Humans; D008297:Male; D008875:Middle Aged; D012086:Reoperation; D014184:Transplantation, Homologous; D016896:Treatment Outcome