title: Choice of mitral prosthesis in the elderly. An analysis of actual outcome.
abstract: BACKGROUND
  In younger patients requiring mitral valve replacement (MVR), mechanical prostheses (MPs) have been reported to give better freedom from all valve-related complications (VRCs) because of the high incidence of late valve degeneration (VD) associated with bioprostheses (BPs). In older patients, however, the risk of VD may be reduced because of the large competing risk of noncardiac death (NCD). Previous studies on VD in the elderly have used actuarial analysis, which overestimates the risk of VD in this population because it assumes that dead patients are still at risk. In contrast, cumulative incidence (actual) analysis acknowledges that patients who die have no risk of VD. This study compares the results of both "actual" and "actuarial" analyses of the freedom from VD in elderly patients undergoing MVR.
  
  
  RESULTS
  From June 1976 through January 1996, 504 patients > or = 70 years of age underwent MVR at our institution. Isolated mitral operations were performed in 159 patients, and 169 had concomitant CABG. Hospital mortality was 59 of 374 (15.9%) for tissue prosthesis versus 24 of 130 (18.5%) for mechanical prosthesis (P = NS). For tissue versus mechanical prosthesis, 10-year freedom from noncardiac death was 75.0% versus 67.6% (P = NS); 10-year actuarial freedom from valve degeneration was 79.8% versus 93.4% (P = NS); 10-year actual freedom from valve degeneration was 92.6% versus 95.4% (P = NS); and 10-year actual freedom from all VRCs was 84.4% versus 92.3% (P = NS).
  
  
  CONCLUSIONS
  In elderly patients undergoing MVR, actuarial analysis overestimates the 10-year risk of VD compared with actual analysis (20.2% versus 7.4% for BP, 6.6% versus 4.6% for MP). In these patients, the actual freedoms from VD and all VRCs do not differ significantly between BP and MP. Thus, in this age group, the necessity for anticoagulation or its avoidance may be the predominant factor in choosing a replacement mitral valve.
authors.affiliation: Department of Surgery, New York University Medical Center, NY 10016, USA. grossi@cv.med.nyu.edu
authors.forename: E A
authors.initials: EA
authors.lastname: Grossi
authors.forename: A C
authors.initials: AC
authors.lastname: Galloway
authors.forename: P K
authors.initials: PK
authors.lastname: Zakow
authors.forename: J S
authors.initials: JS
authors.lastname: Miller
authors.forename: P M
authors.initials: PM
authors.lastname: Buttenheim
authors.forename: F G
authors.initials: FG
authors.lastname: Baumann
authors.forename: A T
authors.initials: AT
authors.lastname: Culliford
authors.forename: F C
authors.initials: FC
authors.lastname: Spencer
authors.forename: S B
authors.initials: SB
authors.lastname: Colvin
mesh_terms: D000206:Actuarial Analysis; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D001705:Bioprosthesis; D019918:Heart Valve Prosthesis Implantation / Q000401:mortality; D017052:Hospital Mortality; D006801:Humans; D015994:Incidence; D008943:Mitral Valve / Q000601:surgery*; D011183:Postoperative Complications / Q000453:epidemiology; D016016:Proportional Hazards Models; D012086:Reoperation; D016896:Treatment Outcome