A prosthesis for the palliation of mitral insufficiency.

Mitral insufficiency results from a failure of the valve leaflets to meet during ventricular systole. During exploratory surgery on patients afflicted with this disease, the observation was made by the authors and others1 that the regurgitant jet could be effectively controlled by the surgeon’s index finger with significant improvement in the action of the heart as long as the finger remained as an obturator in this area of valvular deficiency. This observation suggested a possible therapeutic approach to mitral insufficiency by controlled production of a relative mitral stenosis. Theoretically, this concept would appear feasible as mitral insufficiency is generally less well tolerated than is mitral stenosis in man. Dexter2 has calculated that the functioning mitral valve area may be reduced to two square centimeters without significant elevation of the pulmonary pressure at rest although some rise with exertion may be anticipated. Thus, if one could place a finger-like obturator through the incompetent area of a defective mitral valve such that it would properly fill the insufficient area, the lesion would be palliated provided that at least two square centimeters, or preferably more, of functioning valve area remained. Such a stationary prosthesis would not be dependent upon motion to serve its purpose, and consequently might be better tolerated by the heart and thus able to function indefinitely, especially if the prosthetic material was relatively non-reactive so that compromising adhesions did not form between it and the adjacent valve leaflets. Furthermore, this prosthesis could be shaped at the operating table to the size found necessary for control of the insufficiency. The dilated annulus characteristic of hearts with significant mitral incompetency could be expected to contract appreciably as a consequence of controlling the insufficiency,3 therefore, to maintain maximum valve efficiency it would be desirable for the prosthesis within the mitral orifice to contract also with time at a predictable rate. The interesting properties and the preparation of polyvinyl surgical spongef have been described by Grindlay and Waugh.4 These characteristics include the facts that this material can be molded to any shape, it is relatively non-reactive when inserted into the blood stream, and it will