[The physiologic evaluation of patients before and after mitral commissurotomy].

Cardiac catheterization is a technique which readily lends itself to the analysis of hemodynamic alterations in the cardio-pulmonary circuit caused by mitral stenosis. The purpose of this report is the evaluation of 50 patients with mitral stenosis by means of this technique, attempting thereby to determine optimal indications for mitral commissurotomy. Of the 50 patients studied, 27 subsequently were subjected to commissurotomy. The 50 patients were carefully selected in an effort to exclude all except those with “pure” mitral stenosis. However, two had a significant degree of mitral insufficiency. Seven had minimal aortic insufficiency without signs of peripheral aortic regurgitation such as a collapsing pulse. All had predominantly right ventricular hypertrophy as evaluated by the electrocardiogram or x-ray film. The usual catheterization techniques of Cournand’ were employed and the derived calculations have in general conformed to the methods of Dexter2’ and Bing.6 The patients were divided into three groups on the basis of resting pressure levels in the pulmonary artery and right ventricle. The first group consisted of those whose pulmonary artery systolic pressure was less than 50 mm./Hg. The second group consisted of patients whose pulmonary artery systolic pressure was greater than 50 mm./Hg, and the third group were in failure, i.e.,those with elevated right ventricular diastolic pressure. In all but one In the third group the pulmonary artery systolic pressure was greater than 50 mm./Hg. Thus, in the third group, right ventricular diastolic pressure elevation was an important factor in the high mean pulmonary artery pressure. Table I shows the resting mean pulmonary artery pressure, cardiac output, and pulmonary resistance in the three groups. First, the cardiac output in patients In mitral stenosis without failure is within the normal range. Second, the mean cardiac outputs In Group I and Group II patients are identical. When the right ventricle fails (Group III), there is a further increase in pulmonary artery pressure coincident with a decrease in cardiac output. The differences between the three groups are best brought out by consideration of the ratio of pressure to flow, i.e., resistance. It can be seen to rise markedly from group to group. Between Groups I and II, the increase in resistance is due entirely to the increase in mean pulmonary