[In-vitro studies for the echocardiographic evaluation of abnormal movement of the Starr-Edwards disc prosthesis, in mitral position due to disruption of sutures (author's transl)].

The movement of a Starr-Edwards disc prosthesis was studied in vitro. The best registration of the valve was achieved when the disc was positioned at a 90 degree angle to the echo-beam. At an angle of 45 greater than, there was still a satisfactory registration. Due to an increase of echoes, an exact measurement of the valve excursion proved to be difficult. In the presence of disrupted sutures, which caused tilting of the entire valve apparatus, the amplitude of this movement was superimposed on the amplitude of the disc excursion. The disc showed a so-called "hump" independent from the position of the disrupted suture. A movement of the entire valve apparatus towards or opposite from the transducer caused a similar movement of the disc as the disruption of sutures. These findings support the conception that although a relatively easy echocardiographic registration of the Starr-Edwards disc prosthesis can be obtained, slight changes caused by disrupted sutures cannot be successfully differentiated from movements of the entire valve apparatus with the M-mode echocardiography.