Circulation, Vol 79, 330-336, Copyright © 1989 by American Heart Association
U Nellessen, T Masuyama, CP Appleton, T Tye and RL Popp
To assess the influence of mitral prosthesis malfunction on various Doppler
echocardiographic indexes, we studied the changes in the peak mitral flow
velocity during early diastolic filling phase (Vmax), the mean
transprosthesis pressure drop from the simplified Bernoulli equation, the
mitral valve area by the pressure half-time method, and the left
ventricular isovolumic relaxation time in 15 patients before and after
replacement of the malfunctioning mitral prosthesis using continuous wave
Doppler echocardiography. Examination of the 15 replaced prostheses
revealed a torn or perforated leaflet in 12 valves and a sewing ring
dehiscence in one valve. Additional restricted leaflet motion (classified
as mild obstruction) was seen in three of these 13 valves. In the remaining
two valves, severe prosthesis obstruction was noted. Changes in the Doppler
indexes between the preoperative and postoperative study were present in
all patients regarding Vmax (mean, 2.2 +/- 0.3 versus 1.6 +/- 0.2 m/sec; p
less than 0.001), mean gradient (mean, 9 +/- 5 versus 5 +/- 0.8 mm Hg; p
less than 0.001), and isovolumic relaxation time (mean, 47 +/- 12 msec
versus 80 +/- 13 msec; p less than 0.001). The mean mitral valve area
remained virtually unchanged (2.3 +/- 0.9 versus 2.6 +/- 0.3 cm2; p = NS)
but increased postoperatively in each patient with preoperative mild or
severe prosthesis obstruction without concomitant aortic regurgitation. Our
conclusion is that the peak mitral flow velocity, the mean gradient, and
the isovolumic relaxation time are useful parameters in the differentiation
of normal and abnormal mitral prosthesis function but may not define the
underlying lesion.(ABSTRACT TRUNCATED AT 250 WORDS)
ARTICLES
Mitral prosthesis malfunction. Comparative Doppler echocardiographic studies of mitral prostheses before and after replacement
Division of Cardiology, Stanford University School of Medicine, CA 94305.
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