Longitudinal hemodynamic and clinical study of mitral stenosis.

SUMMARY Forty-two patients with pure mitral stenosis underwent a prospective, longitudinal study with two or more cardiac catheterizations 1 to 10 years apart and without intervening surgical treatment. The majority of patients had not previously had mitral valve surgery; in 16, the period of observation followed valvotomy. Twenty-seven patients showed evidence of progressive obstruction of the mitral valve; 15 showed no change in the calculated mitral valve area. In the group of patients with progressive disease (stenosis or restenosis) there was a consistent clinical and hemodynamic deterioration: 25 of the 27 showed increasing disability. In the nonprogressive group, seven of the 15 showed increasing symptomatology, most often related to the development of atrial fibrillation and a fall in cardiac output. Possible causes for the different course of mitral stenosis in the two groups are reviewed. The probability that trauma due to altered flow patterns through a stenotic valve produces progressive stenosis is suggested. PRESENT-DAY knowledge of the natural history of mitral stenosis is incomplete, being based on clinical or isolated hemody-namic observations.1-'3 The long-term clinical studies by Rowe et al.' and by Olesen2 demonstrate a high mortality in medically treated mitral stenosis. Olesen's study, dealing with symptomatic patients only, showed that only 17% of these survived in an 18-year period.2 Rowe and his associates studied the Mitral valve area entire spectrum of mitral stenosis, and found that 21% of the patients survived 20 years. Using these data, Ellis et al.3 demonstrated that mitral valvotomy produces a significant reduction in mortality. Clinical studies, such as those quoted above, fail to provide information regarding the most crucial question pertaining to the natural history of mitral stenosis: is the clinical deterioration caused by a progression of the valve disease, or is it caused by secondary sequelae in a condition that is "burned out" early in life? An ideal way of determining the course of mitral valve obstruction would be the organization of a longitudinal study, with repetition of hemodynamic measurements at intervals. Such a study, however, could not take place today, for it is not possible to withhold surgical treatment from severely disabled patients. The present, prospective study deals with data gathered from periodic reevaluation of patients with mitral stenosis in whom 381