[Clinical and hemodynamic studies before and after mitral valve replacement (author's transl)]

Clinical and hemodynamic studies were carried out before and after replacement of stenotic mitral valves in 17 patients, 10 of whom received Björk-Shiley (low profile mechanical) prostheses and 7 who received (porcine heterograft) bioprostheses. Mitral valve replacement led to amelioration of symptoms, improvement of phonocardiographic findings and, partially, to a lowering of pressure in the pulmonary circulation, augmentation of cardiac output, lessening of the pulmonary arteriolar and mitral valvular resistances as well as incrementation of mitral valve orifice area. Preexistent ECG changes, radiologic heart size, right ventricular filling pressure and stroke volume remained unaltered. In consideration of variables such as prosthetic size, severity of the disease and post-operative follow-up periods, the results obtained with both types of prostheses were comparable. The prostheses, however, inherently are responsible for a moderate degree of mitral stenosis which compromises exercise capacity and generally does not lead to normalization of pressure in the pulmonary circulation. Irreversible myocardial damage appears responsible for the fact that electrocardiographic abnormalities, the heart size, the right ventricular filling pressure and stroke volume remain unaltered postoperatively. Thus, patients who have undergone mitral valve replacement continue to require limitation of physical activities, a tailored medical regimen and close cardiologic follow-up.