Mitral replacement: Clinical experience with a ball-valve prosthesis. Twenty-five years later

The purpose of this report is to review the results of mitral valve replacement since a first report in the Annals of Surgery in 1961, in order to determine the relative importance of new valve designs versus other surgical variables. The continued use of the silastic ball valve in its 1966 configuration (Model 6120), by providing a comparative data base for other new prosthetic valves, allows this analysis. For a valid comparison with the tilting disc (Bjork-Shiley) and the porcine (Hancock and Carpentier-Edwards) valves, only the results with the silastic ball valves implanted during comparable time frames should be used. There are no significant differences in the results obtained with the silastic ball valve in time frames comparable to other contemporary valves introduced in the early 1970s. Improved results, therefore, must be nonprosthetic valve related.