Open-position fixation of bioprostheses for more physiological performance. Fluoroscopic observations of leaflet movements in vivo.
A new model of the stent-mounted porcine aortic bioprosthesis was prepared with 0.625% glutaraldehyde while the valve was partially open. A radiopaque marker was attached to the center of the free margin of each leaflet so that the leaflet movements could be observed in an in vivo testing unit by fluoroscopic cinematography. This valve was compared with a porcine xenograft that currently is available commercially. While the heart was beating, the specially prepared leaflets showed some characteristics that contrasted with those of the currently used bioprosthesis. These features included (1) uniformity versus asymmetry of leaflet excursions under low flow conditions, (2) slower and more gradual closing (actual closing time averaging 536 msec versus 81 msec), and (3) more prolonged period of valve opening, the duration of opening averaging 60% versus 49% of the cardiac cycle. These features support the validity of open-position fixation as a means of further improving xenograft durability.
D000818:Animals; D001705:Bioprosthesis; D002933:Cineradiography; D004285:Dogs; D006041:Goats; D006350:Heart Valve Prosthesis; D006439:Hemodynamics; D008722:Methods; D008943:Mitral Valve / Q000601:surgery; D008954:Models, Biological; D013997:Time Factors