[Crenelation of Beall's prostheses in mitral position: apropos of 21 reoperated cases].

The authors report their experience of 21 revision operations for malfunction of the Beall Surgitool 104 prosthesis used in the mitral position. The incidence and uniformity of the disorders found in the prostheses suggest that these changes are produced inevitably usually during the fourth year. The disc becomes kinked, the mountings eroded, and the teflon ring torn. The clinical features are the onset of heart failure, anaemia, or a thrombo-embolic episode. These three findings may occur individually or in association. The authors do not advise systematic revision surgery, but conclude that close follow-up is essential in the case of all patients who have had a Beall prosthesis. Early signs of failure should be revealed by clinical examination, the level of LDH, and by phonocardiogram and echocardiogram studies. Leaving aside thrombo-embolic episodes and severe anaemia which themselves constitute indications for revision surgery, the decision to replace the damaged prosthesis should be taken as soon as the first signs of cardiac failure are detected.