title: Twelve-year comparison of a Bjork-Shiley mechanical heart valve with porcine bioprostheses.
abstract: BACKGROUND
  Patients undergoing heart-valve replacement may receive a mechanical prosthesis, necessitating lifelong anticoagulant treatment, or a porcine bioprosthesis, which involves no absolute need for anticoagulants.
  
  
  METHODS
  We carried out a randomized, prospective trial to compare the durability of the Bjork-Shiley mechanical prosthesis (spherical tilting-disk model) and the incidence of valve-related complications with those variables in the Hancock and the Carpentier-Edwards porcine prostheses. The mitral valve was replaced in 261 patients, the aortic valve in 211, and both in 61; the survivors have been followed up for a mean of 12 years.
  
  
  RESULTS
  We found a trend toward improved actuarial survival after 12 years with the Bjork-Shiley prosthesis, but this trend was not statistically significant (group with Bjork-Shiley valve vs. group with porcine valve [mean +/- SE], 51.5 +/- 3.2 vs. 44.4 +/- 3.2 percent; P = 0.08). There was no significant difference in the actuarial incidence of reoperation after 5 years, but after 12 years significantly more patients with a porcine prosthesis had undergone reoperation (8.5 +/- 2.0 vs. 37.1 +/- 4.1 percent, P less than 0.001). An analysis combining death and reoperation as end points for an actuarial assessment of survival with the original prosthesis intact confirmed that the patients with Bjork-Shiley Shiley prostheses had improved survival (48.6 +/- 3.2 vs. 30.0 +/- 3.0 percent after 12 years, P less than 0.001). Bleeding requiring hospitalization or blood transfusion was significantly more frequent in the patients with Bjork-Shiley prostheses (18.6 +/- 3.2 vs. 7.1 +/- 2.3 percent after 12 years, P less than 0.01). There was no significant difference after 12 years in the actuarial occurrence of embolism (Bjork-Shiley vs. porcine, 21.1 +/- 3.1 vs. 26.4 +/- 3.5 percent) or endocarditis (3.7 +/- 1.4 vs 4.6 +/- 1.6 percent).
  
  
  CONCLUSIONS
  Survival with an intact valve is better among patients with the Bjork-Shiley spherical tilting-disk prosthesis than among patients with porcine bioprostheses, but use of the Bjork-Shiley valve carries an attendant increased risk of bleeding associated with the need for anticoagulant treatment.
authors.affiliation: Department of Cardiology, Royal Infirmary of Edinburgh, Scotland.
authors.forename: P
authors.initials: P
authors.lastname: Bloomfield
authors.forename: D J
authors.initials: DJ
authors.lastname: Wheatley
authors.forename: R J
authors.initials: RJ
authors.lastname: Prescott
authors.forename: H C
authors.initials: HC
authors.lastname: Miller
mesh_terms: D000206:Actuarial Analysis; D000368:Aged; D001705:Bioprosthesis; D004617:Embolism / Q000209:etiology; D004697:Endocarditis, Bacterial / Q000209:etiology; D005260:Female; D006350:Heart Valve Prosthesis / Q000009:adverse effects / Q000401:mortality; D006801:Humans; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve / Q000601:surgery; D011183:Postoperative Complications; D011446:Prospective Studies; D011475:Prosthesis Failure; D012086:Reoperation; D015996:Survival Rate