title: When and how does nonstructural mechanical prosthetic heart valve dysfunction occur?
abstract: OBJECTIVE
  We discuss the clinical aspects related to mechanical valve dysfunction based upon 20 years' experience of our cases.
  
  
  METHODS
  Between January 1982 and December 2001, 21 patients underwent surgical interventions because of mechanical valve dysfunction. Thirteen men and 8 women (mean age 47 +/- 20, range 3-75 years-old), were included.
  
  
  RESULTS
  Mitral valve dysfunction was observed in 12 patients. Prosthetic valve stenosis occurred in 6 patients between 2 and 224 months, and paravalvular leaks in 4 between 1 and 71 months after surgery. The other 2 patients suffered from hemolytic anemia with mild paravalvular leaks between 102 and 104 months after surgery. Aortic valve dysfunction was observed in 8 patients including 3 stenotic lesions between 48 and 97 months and 5 paravalvular leaks between 3 and 150 months after surgery. Tricuspid regurgitation was seen in 1 patient with a huge right atrium at 42 months after surgery. Early death was seen in 1 patient. Late death occurred in 1 patient, 17 years after operation. Survival, including early death, was 95.2%, at 10 and 15 years. One valve-related complication of bioprosthetic valve endocarditis at the mitral and tricuspid positions occurred 12 years after a reoperation. The freedom from complications was 95.2% at 10 years, and 76.2% at 15 years.
  
  
  CONCLUSIONS
  Paravalvular leaks without overt endocarditis had latency periods of up to 12 years, and pannus formation was observed 20 years after surgery. Early and late clinical results after surgery for mechanical valve dysfunction were excellent.
authors.affiliation: Division of Cardiovascular Surgery, Jichi Medical School, Minami-kawachi, Tochigi, Japan.
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Misawa
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Saito
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Konishi
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Oki
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Kaminishi
authors.forename: Hideki
authors.initials: H
authors.lastname: Takahashi
authors.forename: Kei
authors.initials: K
authors.lastname: Aizawa
authors.forename: Osamu
authors.initials: O
authors.lastname: Kamisawa
authors.forename: Morito
authors.initials: M
authors.lastname: Kato
authors.forename: Katsuo
authors.initials: K
authors.lastname: Fuse
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001021:Aortic Valve / Q000503:physiopathology / Q000601:surgery; D001705:Bioprosthesis; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006349:Heart Valve Diseases / Q000401:mortality / Q000503:physiopathology / Q000601:surgery; D006350:Heart Valve Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve / Q000503:physiopathology / Q000601:surgery; D011475:Prosthesis Failure; D012720:Severity of Illness Index; D016896:Treatment Outcome; D014261:Tricuspid Valve / Q000503:physiopathology / Q000601:surgery