title: Bileaflet mechanical prostheses performance in mitral position.
abstract: OBJECTIVE
  The experience with the Carbomedics (CM) and the St. Jude Medical (SJM) bileaflet mechanical prostheses was evaluated to determine thromboembolic and hemorrhagic complications and predictive risk factors.
  
  
  METHODS
  From 1989 to 1994, a total of 625 patients had mitral valve replacement (CM, 240; SJM, 385); 32.5% (203), concomitant procedures and 32.8% (205), previous cardiac surgery, primarily valve replacement procedures.
  
  
  RESULTS
  The pre-operative variables did not distinguish the populations, except for previous surgery CM 37.9% and SJM 29.6% (P < 0.05). The pre-operative variables (type of prostheses, cardiac rhythm, coronary artery bypass, NYHA III/IV, advancing age, gender, urgency status and previous surgery) were not predictive of overall thromboembolism (TE), major TE, minor TE, prosthesis thrombosis and hemorrhage (P not significant; P = NS). The linearized rate of total TE events for overall MVR was 5.0%/patient-year (CM 4.4; SJM 5.4). The < or = 30 day major crude rate was 0.44%, while the > 30 day late major event rate was 2.0%/patient-year. Of the total TE events 91% of < or = 30 days and 75%, > 30 days had an INR < 2.5 at or immediately prior to the event. The thrombosis rate (included in TE events) was 0.63%/patient-year (ten events, four managed successfully with thrombolysis, five successfully with reoperation, and one fatality identified at autopsy). The freedom, at 5 years, from major/fatal TE, thrombosis and hemorrhage from anticoagulation was 88.2%, and 89.5% exclusive of early events.
  
  
  CONCLUSIONS
  This non-randomized prospective observational evaluation of the CarboMedics and St. Jude Medical prostheses has not revealed any differentiation in performance of the prostheses. The study serves as a single institution experience with the potential for future comparative evaluation.
authors.affiliation: St. Paul's Hospital-Heart Center, Vancouver General Hospital, University of British Columbia, Canada.
authors.forename: W R
authors.initials: WR
authors.lastname: Jamieson
authors.forename: R T
authors.initials: RT
authors.lastname: Miyagishima
authors.forename: G L
authors.initials: GL
authors.lastname: Grunkemeier
authors.forename: E
authors.initials: E
authors.lastname: Germann
authors.forename: C
authors.initials: C
authors.lastname: Henderson
authors.forename: G J
authors.initials: GJ
authors.lastname: Fradet
authors.forename: L H
authors.initials: LH
authors.lastname: Burr
authors.forename: S V
authors.initials: SV
authors.lastname: Lichtenstein
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002561:Cerebrovascular Disorders / Q000209:etiology; D005260:Female; D006350:Heart Valve Prosthesis / Q000009:adverse effects*; D019918:Heart Valve Prosthesis Implantation / Q000009:adverse effects / Q000401:mortality; D006470:Hemorrhage / Q000209:etiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve / Q000601:surgery*; D011446:Prospective Studies; D011474:Prosthesis Design; D012307:Risk Factors; D013923:Thromboembolism / Q000209:etiology