[20 years of mitral valve replacement. Development of a patient profile and operative mortality].

Between 1971 and 1991, 1,179 mitral valve replacements (MVR) were carried out in 1,134 patients. The sex ratio was stable over this period (0.7 men/women) whereas the average age of the patients increased by 10 years (50 years in 1971, 61 years in 1991). Since 1980, patients over 60 years of age represent about 60% and those over 70 years of age 16 to 22% of the population. The functional status of the patients has tended to be less severe, the NYHA stages III and IV which were initially preponderant, only represent 50 to 60% of patients operated nowadays. This reduction in the severity of symptoms is reflected in the average value of the cardio thoracic index which was 60 in 1971 and 54.8 in 1991. Similarly, the mean pulmonary artery pressures (measured in 823 patients, 69.8%) have decreased from 37.4 mmHg in 1971 to 29.9 mmHg in 1991. Rheumatic fever has tended to be replaced by degenerative etiologies which, since 1985, represent 40 to 50% of cases. Ischemic mitral regurgitation rare before 1980, is more common, presently making up 5 to 15% of MVR cases. In relation with the etiological changes mitral stenosis is giving way to mitral regurgitation as the commonest valve lesion (40 to 50% of cases in 1991). The annual operative mortality is lower (6 to 8%) than in 1982, despite the increasing number of emergency cases (7 to 10% of cases since 1985). The number of MVR with associated tricuspid valve repair has decreased with respect to isolated MVR or associated with aortocoronary bypass grafting. The only constant feature is the death rate due to myocardial dysfunction which remains over 50% whereas mortality related to the prosthetic valves varied over the years.