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[Quantification of valvular stenosis by Doppler echography].

Doppler echocardiography has made decisive advances in the non-invasive quantification of valvular stenosis. The simplified Bernoulli formula gives access to the maximum and mean transvalvular pressure gradients which correlate very well with the gradients measured at catheterisation. In addition, it is possible to calculate valve surface area in aortic and mitral stenosis from the continuity equation providing its conditions of application are respected. The Doppler surface area of mitral stenosis can also be estimated with some reservations by measuring pressure half time. Doppler echocardiography provides a reliable non-invasive hemodynamic study of valvular stenosis and should lead to a reduction in the number of indications of cardiac catheterisation, especially as pulmonary artery pressures can be determined from Doppler recordings of tricuspid and pulmonary regurgitation.