Results of valve replacement surgery with mechanical prostheses.

The clinical study is reported of the results of heart valve replacement surgery with a new pyrolytic carbon tilting disc prosthesis manufactured in Italy. From March 1977 to January 1981, at the "De Gasperis" Cardiosurgery Center, this prosthesis has been implanted in 644 patients: 283 for mitral valve replacement, 240 for aortic valve replacement, and 121 for the replacement of both mitral and aortic valves. To have a sufficiently long period of post-surgery follow-up, we considered the results of 207 patients (124 cases of isolated mitral valve replacement and 83 cases of isolated aortic valve replacement), who underwent surgery consecutively from March 1977 to December 1979. The hospital mortality was 10.5% for mitral valve replacement and 4.8% for aortic valve replacement. All patients who were discharged from hospital, except 2, were subjected to clinical, electrocardiographic, phonocardiographic, echocardiographic and radiological checks. The average follow-up period was approximately 20 months: clinical results were satisfactory. The probability of survival, expressed by actuarial curve, was, three years after surgery, 94% for patients who underwent mitral valve replacement and 97.5% for those who underwent aortic valve replacement. The probability of embolism was, three years after surgery, 8.5% for patients with mitral replaced and 5% for aortic. Even if further confirmations are needed the mortality rate and the probability of embolism related to this new prosthesis, are lower, over the same period of follow-up, than that found in the groups of patients who underwent valve replacement surgery, at the same Center, with Starr-Edwards and Björk-Shiley prostheses. The phonocardiographic and echocardiographic characteristics of this new prosthesis were also investigated.