Evaluation of the severity of mitral stenosis and regurgitation.

Indices have been developed that provide an improved means for evaluation of the degrees of severity of mitral stenosis and regurgitation. The severity of anatomic mitral valve disease found at surgery or autopsy was considered to be the determinant of the state of the valve. An index of the time for the diastolic atrioventricular pressure gradient to fall to half its value multiplied by 100 and divided by the cardiac index was shown to be comparable to the severity of anatomic stenosis. This index ranged from 5.7 to 10 in mitral stenosis, 0.4 to 0.8 in normal subjects, and 0.6 to 2.0 in patients with predominant mitral regurgitation. Mitral regurgitation was estimated by an index of the rate of the atrial pressure rise during ventricular systole in mm. Hg/0.02 second multiplied by 10, and divided by the cardiac index. In predominant mitral regurgitation, this index ranged from 8.0 to 15; in mitral stenosis these values were 3.7 to 6.3, and normal subjects had an index varying from 2.5 to 3.7. Both indices were significantly elevated in patients in whom stenosis and regurgitation were present at surgery. Mitral stenosis complicated by a mild degree of regurgitation gave significantly elevated stenotic indices, while the regurgitation indices were normal or slightly elevated. These indices facilitate the evaluation of either mitral stenosis or regurgitation even when both processes are present together. The significance of these indices in the evaluation of the degree of invalidism in patients with valvular disease is also discussed.