[Pathoanatomical features of isolated congenital mitral stenosis in twins (author's transl)].

The pathoanatomical features of isolated congenital mitral stenosis in female twins are presented. At the age of 7 months one of the infants underwent an emergency mitral valvotomy and died the next day due to mitral insufficiency. A total mitral valvectomy and an implantation of a Björk-Shiley prosthesis were performed on the second child at the age of 27 months. Death occurred 6 months later due to malfunction of the prosthesis caused by a circular fibrous endocardial bulge on both the atrial and ventricular side of the prosthesis. The bulging endocardial fibrosis may have been favored by a local thrombosis, which was found circularly around the bed of the prosthesis after it was removed. Since the child suffered from postoperative serum hepatitis, anticoagulants could not be applied on a regular basis in sufficient doses. The relation of the endocardial fibroelastosis to the congenital valve disease and the implantation of a prosthesis is discussed. The site of the postoperative valve in the first child and the state of the second child after implantation of the mitral valve prosthesis are discussed in detail.