title: Comparison of outcome after valve replacement with a bioprosthesis versus a mechanical prosthesis: initial 5 year results of a randomized trial.
abstract: The Veterans Administration Cooperative Study on Valvular Heart Disease was organized to compare survival and incidence of valve-related complications between patients receiving a bioprosthesis (the Hancock porcine heterograft) and a mechanical prosthesis (the Björk-Shiley spherical disc valve). Five hundred seventy-five patients undergoing single aortic or mitral valve replacement were randomized at surgery to one of the two valve types. At an average follow-up of 5 years (range 3 to 8) there are no statistically significant differences in survival between patients with the two valve types in the aortic valve replacement group. There is a statistically nonsignificant trend toward improved survival in patients undergoing mitral valve replacement with a bioprosthesis compared with a mechanical prosthesis (5 year survival probability was 0.70 +/- 0.05 and 0.58 +/- 0.06, respectively). Fatal and nonfatal valve-related complications occurred significantly less frequently in patients with a bioprosthesis compared with a mechanical prosthesis for both mitral and aortic valve replacement. Five year complication-free probability was 0.67 +/- 0.05 and 0.45 +/- 0.06, respectively, for patients with mitral valve replacement and 0.63 +/- 0.04 and 0.53 +/- 0.04, respectively, for those with aortic valve replacement. The difference in overall complication rates was largely due to the increased number of clinically significant but nonfatal bleeding episodes in patients receiving a mechanical prosthesis. Adjustment for differences in baseline characteristics between patients receiving a mitral mechanical prosthesis and a mitral bioprosthesis reduced the statistical significance of the difference in both mortality and complications.
authors.affiliation: Cardiology Section, VA Medical Center, Denver, Colorado 80220.
authors.forename: K E
authors.initials: KE
authors.lastname: Hammermeister
authors.forename: W G
authors.initials: WG
authors.lastname: Henderson
authors.forename: C M
authors.initials: CM
authors.lastname: Burchfiel
authors.forename: G K
authors.initials: GK
authors.lastname: Sethi
authors.forename: J
authors.initials: J
authors.lastname: Souchek
authors.forename: C
authors.initials: C
authors.lastname: Oprian
authors.forename: A B
authors.initials: AB
authors.lastname: Cantor
authors.forename: E
authors.initials: E
authors.lastname: Folland
authors.forename: S
authors.initials: S
authors.lastname: Khuri
authors.forename: S
authors.initials: S
authors.lastname: Rahimtoola
mesh_terms: D001021:Aortic Valve / Q000601:surgery; D001705:Bioprosthesis / Q000009:adverse effects / Q000401:mortality*; D002986:Clinical Trials as Topic; D005500:Follow-Up Studies; D006350:Heart Valve Prosthesis / Q000009:adverse effects / Q000401:mortality*; D006470:Hemorrhage / Q000209:etiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve / Q000601:surgery; D011474:Prosthesis Design; D011897:Random Allocation; D012086:Reoperation; D013923:Thromboembolism / Q000209:etiology