THE BALL-and-cage prosthesis has proved to be a reliable mechanical substitute for the destroyed mitral valve, despite its practical and theoretical limitations. Hospital mortality following cardiac valve replacement has been reduced to that of other major surgical procedures on similar patients. Valves have continued to perform well as long as seven years after implantation. The high reported incidence of late thromboembolic complications, however, has discouraged use of these prostheses1-5 earlier in the course of disease.
Material and Methods
Between December 1963 and July 1967, 100 patients underwent mitral valve replacement at the University of California Medical Center. Seventy-two patients are still alive 6 to 48 months after their operations. Forty-five patients have been seen for more than two years. Ninety percent of the patients are being seen in our cardiac clinic or in our private practices. Follow-up information in the remaining patients was obtained by personal communication with the