Does mitral valve replacement with the St Jude medical prosthesis improve echocardiographic left ventricular filling characteristics compared to Starr-Edwards or Björk-Shiley prostheses or native mitral valve repair?
The St Jude medical prosthesis demonstrates less obstructive left ventricular filling characteristics compared to older mechanical valves, closely mimicking native mitral valve repair.
The major cause of late mortality and morbidity after prosthetic valve replacement is thromboembolism. The nidus for initiation of thrombus formation has been blood metal interfaces, and a new valve--the St Jude prosthesis--has therefore been developed without any metal components. We have assessed echocardiographically in 27 patients the effects of this valve on left ventricular filling characteristics when inserted in the mitral position and compared the findings with those in patients having mitral valve replacement with Starr-Edwards or Björk-Shiley prostheses and with those in patients undergoing repair of the native mitral valve. Echocardiograms were recorded and digitised. Measurements were made of the peak rate of increase of dimension (dD/dt) and duration of rapid filling. Values for the St Jude valve were 13.2 +/- 3.4 cm/s and 160 +/- 40 ms, respectively. The peak rate of dD/dt increase was significantly greater than with either the Björk-Shiley valve or the Starr-Edwards valve and was comparable with findings in mitral valve repair. The duration of the rapid filling phase was not significantly different from control values but was less than that of the Starr-Edwards valve. This study indicates that the new St Jude medical valve is less obstructive than either the Björk-Shiley or Starr-Edwards prostheses. This together with its low thrombogenicity suggests that further trials of this new valve should be undertaken.
Sutton et al. (Wed,) studied this question.