[Doppler echocardiographic determination of aortic valve gradients].

Doppler-echocardiography is the most important non invasive method for the assessment of the severity of aortic stenosis. After measuring the maximal transstenotic flow velocity (= Vmax) the maximal pressure drop between left ventricle and aorta (= maximal instantaneous gradient) can bei calculated according to a simple formula. The accurate determination of Vmax may be difficult and time consuming, however, and when interpreting the Doppler-data it is important to realize that there is always a systematic numerical difference between the instantaneous gradient and those gradients which one usually measures at catheterization (peak to peak and mean gradient respectively). In mixed aortic valve disease the aortic insufficiency will distort the relationship between the various gradients still further. Despite these problems Doppler-echocardiography is extraordinarily useful in quantitating aortic stenosis and obviates the need for catheterization in most patients.