[Validation of a method for measuring the area of aortic stenosis using only continuous Doppler. Value for the surveillance of transluminal aortic valvuloplasties].

Forty patients with aortic valve stenosis underwent continuous wave doppler-echocardiographic exploration followed by catheterization within 24 hours on average. Three methods of aortic functional area calculation, based on the continuity equation principle, were tried and compared with the haemodynamic data. The results of the reference equation (continuity through the whole systole) gave a correlation coefficient r = 0.77 with a standard error (SE) of 0.17 cm2. The continuity equation using only maximum velocity values was less satisfactory: r = 0.69; SE = 0.19 cm2. The simplified equation with an arbitrary 2 cm subaortic diameter and a subaortic velocity obtained by continuous wave doppler recording yielded results that were very similar to those of the reference equation: r = 0.78; SE = 0.16 cm2. It is suggested that this third equation should be used in the follow-up of transluminal aortic valvuloplasties, since its calculation is based only on aortic velocity, which reflects the degree of stenosis, and subaortic velocity, which indirectly reflects left ventricular function.