Pulmonary function in mitral valve disease: Hemodynamic and ventilatory studies

Abstract

Hemodynamic and ventilatory studies were carried out in a large series of patients who underwent mitral surgery for mitral stenosis or insufficiency. A diminution of cardiac index was found, which paralleled the narrowing of the mitral orifice. However, left ventricular failure seemed to be operative in some of the cases, even in the presence of pure, tight mitral stenosis. This hypothesis was also suggested by the observation that pulmonary artery and venous wedge pressures were significantly higher in patients with combined heart failure, independently of the size of the mitral orifice. A positive linear correlation was found between pulmonary artery pressures and pulmonary vascular resistances, when the latter were more than 200 and less than 900 dynes sec cm −5. No significant increase of pulmonary blood volume could be found in patients with mitral stenosis. Lack of correlation was found between ventilatory and hemodynamic findings studied simultaneously in 50 patients. Vital capacity was significantly impaired only in decompensated patients. Residual volume was increased in every case of mitral disease. Ventilatory dynamics were also altered in every instance, particularly when congestive heart failure was present. Functional dead space was consistently increased, in spite of an increased alveolar ventilation. These findings confirm that in mitral stenosis the ventilatory perfusion ratio is consistently impaired. Results of postcommissurotomy ventilatory studies were quite variable in spite of good clinical results. In 26 patients the hemodynamic behavior was studied before and at varying intervals (30 days to 3.5 years) after mitral commissurotomy. The hemodynamic findings in patients who underwent a successful commissurotomy are similar to those observed in subjects with anatomically and functionally mild mitral stenosis.