title: Outcomes of patients subjected to aortic valve replacement surgery using mechanical or biological prostheses.
abstract: OBJECTIVE
  This paper evaluates outcomes in patients subjected to surgery for replacement of the aortic valve using biological or mechanical substitutes, where selection of the type of prosthesis is relevant.
  
  
  METHODS
  Three hundred and one patients, randomly selected, who had been subjected to aortic valve replacement surgery between 1990 and 2005, with a maximum follow-up period of 20 years.
  
  
  RESULTS
  Survival at 5, 10 and 15 years after surgery using mechanical substitute was 83.9%, 75.4% and 60.2% and, for biological substitute, was 89.3%, 70.4% and 58.4%, respectively (P = 0.939). Factors associated with death were: age, obesity, pulmonary disease, arrhythmia, bleeding and aortic valve failure. Probability free of reoperation for these patients at 5, 10 and 15 years after surgery using mechanical substitute was 97.9%, 95.8% and 95.8% and, for those using bioprostheses, was 94.6%, 91.0% and 83.3%, respectively (P = 0.057). Factors associated with reoperation were: renal failure, prosthesis endocarditis and age. Probability free of bleeding events at 5, 10 and 15 years after surgery using mechanical substitute was 94.5%, 91.7% and 91.7% and, for bioprostheses, was 98.6%, 97.8% and 97.8%, respectively (P = 0.047). Factors associated with bleeding events were: renal failure and mechanical prostheses.
  
  
  CONCLUSIONS
  The authors have concluded that: 1) mortality was statistically similar in the groups; 2) patient characteristics at baseline were a major determinant of late mortality after surgery; 3) there was a tendency toward reoperation in the bioprostheses group; 4) patients using mechanical prosthesis had more bleeding events as time passed; 5) data presented in this paper is in accordance with current literature.
authors.affiliation: Serviço de Cirurgia Cardiovascular, Cardiologia e Ciências Cardiovasculares pela Universidade Federaldo Rio Grande do Sul, Porto Alegre, RS, Brasil. adrianasdealmeida@gmail.com
authors.forename: Adriana Silveira de
authors.initials: AS
authors.lastname: Almeida
authors.forename: Paulo Dornelles
authors.initials: PD
authors.lastname: Picon
authors.forename: Orlando Carlos Belmonte
authors.initials: OC
authors.lastname: Wender
mesh_terms: D000368:Aged; D001021:Aortic Valve / Q000601:surgery*; D001705:Bioprosthesis / Q000009:adverse effects* / Q000706:statistics & numerical data; D001938:Brazil / Q000453:epidemiology; D002423:Cause of Death; D004812:Epidemiologic Methods; D006350:Heart Valve Prosthesis / Q000009:adverse effects*; D019918:Heart Valve Prosthesis Implantation / Q000379:methods / Q000401:mortality*; D006801:Humans; D008875:Middle Aged; D019106:Postoperative Hemorrhage / Q000453:epidemiology*; D012086:Reoperation / Q000706:statistics & numerical data; D016896:Treatment Outcome