FUNCTIONAL-EVALUATION OF THE BILEAFLET MECHANICAL VALVE IN THE AORTICPOSITION USING DOBUTAMINE-STRESS ECHOCARDIOGRAPHY - IS A 23-MM PROSTHETIC VALVE ADEQUATELY LARGE ENOUGH
M. Tsukamoto et al., FUNCTIONAL-EVALUATION OF THE BILEAFLET MECHANICAL VALVE IN THE AORTICPOSITION USING DOBUTAMINE-STRESS ECHOCARDIOGRAPHY - IS A 23-MM PROSTHETIC VALVE ADEQUATELY LARGE ENOUGH, Japanese Circulation Journal, 62(11), 1998, pp. 817-823
The issue of valve prosthesis-patient mismatch in small annular patien
ts is still controversial. The hemodynamic function of bileaflet mecha
nical valves in the aortic position was examined using dobutamine-stre
ss echocardiography. Forty-four patients were enrolled in the study an
d divided into 5 groups, according to prosthesis size, from 21 mm to 2
9 mm. The aortic peak pressure gradient (APG) increased significantly
in all groups with dobutamine-stress and exceeded 50 mmHg in 83% of th
e 21-mm group, in 64% of the 23-mm group, and in 33% of the 25-mm grou
p. The APG even exceeded 80 mmHg in 22% and 18% of the 21-mm and 23-mm
groups, respectively. In these cases, the potential of 'valve prosthe
sis-patient mismatch' was considered. From the relationship between th
e APG and the prosthesis valve area index (VAI), 'critical VAIs' were
found where patients were Likely to enter the 'mismatch' status; that
is, 1.22 and 1.77 cm(2)/m(2), respectively, for the 5 and 10 mu g/kg p
er min stages of dobutamine stress. This critical VAI range is useful
in predicting the 'mismatch' patients preoperatively. Alternative proc
edures or prostheses should then be selected for them.