OTHER AUTHORS have reported the continued use of closed mitral commissurotomy,1 which can be a reasonably safe procedure so long as there is little or no calcification of the valve, minimal regurgitation, and no thrombus within the left atrial cavity or appendage. When these criteria have been met, the long-term results of closed commissurotomy have been satisfactory.
The use of the transventricular dilator for the tough, fibrous, fused valve has improved the results of dilatation and diminished the incidence of persistent mitral stenosis. Reoperation has been necessary for patients who have had open surgical procedures as well as those who have had closed. Insufficient time has elapsed to be certain that a dilatation or commissurotomy with direct vision has decreased the incidence of persistent or recurrent stenosis. Furthermore, a second operation by the open technique following a closed procedure has, in our experience, entailed less risk than a second