[Comparative study of 2 mechanical mitral valves]

We present the long term follow-up of two groups of patients under 16 years of age in whom two different types of mitral valve prostheses were used for the treatment of mitral valve disease. Group I was formed by 74 patients with Starr-Edwards (6120) prosthesis and group II by 36 cases with Bjork-Shiley prosthesis. Group I was followed for a mean period of 11 years and group II for a mean period of 7.5 years. The clinical evolution of both groups assessed according to the New York Heart Association criteria showed improvement of the functional class (p less than 0.006). Twenty seven cases of group I and 21 of group II underwent cardiac catheterization for the evaluation of surgical results. In group I, the mean pulmonary arterial systolic pressure (PASP) decreased from 57 mmHg to 33 mmHg (p less than 0.001) and the mean pulmonary arterial wedge pressure (PAWP) from 20.8 mmHg to 12.1 mmHg (p less than 0.05). In group II, the mean PASP decreased from 59.2 mmHg to 28.5 mmHg (p less than 0.001) and the mean PAWP from 24.6 mmHg to 8.5 mmHg (p less than 0.001). There was statistically significant difference for a greater incidence of thromboembolism in group I (p = 0.037). No differences were found for bacterial endocarditis, dysfunction and death.