After replacement of heart valves, it is desirable to evaluate the movement of prosthetic valves. Echocardiography has been found to be useful for this purpose in the either mitral or aortic position.
59 consecutive cases of prosthetic valve replacement were examined with this method.
In 22 cases of the mitral ball valve prosthesis, the movement of the ball and the cage, opening and closing velocities, poppet excursion and the ball diameter were measured. Average opening and closing velocities were 60mm/sec and 42mm/sec. Much difference in the velocities of ball movement was observed in individual patient. Moreover, it changed greatly from one heart beat to another especially in cases with arrhythmia.
The Echocardiographic pattern of a normally functioning mitral ball valve prosthesis demonstrated great similarity to that of severe mitral stenosis. There were many kinds of Echocardiographic patterns in mitral Björk-Shiley disc valves. It seemed to be because of difficulty to keep the same angle between the direction of the ultra sonic beams and the movement of the tilting disc of the Björk-Shiley valve.
Although the movement of the aortic valve prosthesis were detectable on Echocardiography, detailed analysis has not been completed in our study.
An 8 year-old inl had developed signs and symptoms of malfunction of a Björk-Shiley disc valve (No. 25) and showed changes of Echocardiographic patterns of restricted disc movement in serial postoperative studies.
At re-operation and valve replacement, we discovered thrombi encroaching on both sides of the valve orifice.
The other patient was a 41 year-old male who had had both mitral and aortic value replacement a month ago. In spite of clinical findings of malfunction of the prosthesis, Echocardiography revealed pericardial effusion instead of a pattern of malfunction.
It is effective and mandatory to perform serial postoperative studies on all patients with prosthetic valves.
