title: An examination of two retrieved long-term human implant Björk-Shiley valves.
abstract: Two retrieved long-term human implant Björk-Shiley valve prostheses were examined for wear. The prostheses were retrieved at necropsy from a double implant patient that had died from causes unrelated to the valves twelve years post implantation. Both prostheses were the Björk-Shiley conical tilting disc type heart valves with Haynes 25 alloy orifice and a Pyrolite Carbon disc. A size 21 mm valve had been implanted in the aortic position and a size 27 mm valve had been implanted in the mitral position. Wear had occurred on the valves in regions of mutual contact between the disc and orifice struts during valve opening and closing. Wear mark depths and types were consistent with previous observations on Pyrolite Carbon Björk-Shiley and Lillehi-Kaster prostheses. No evidence of cavitation nor strut fatigue damage was observed on either valve prosthesis. Wear that occurred on the valves was insignificant and of no consequence to valve function.
authors.affiliation: CarboMedics, Austin, TX 78752.
authors.forename: R B
authors.initials: RB
authors.lastname: More
mesh_terms: D001021:Aortic Valve; D006350:Heart Valve Prosthesis; D006439:Hemodynamics; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D008943:Mitral Valve; D011474:Prosthesis Design; D013314:Stress, Mechanical; D013997:Time Factors