[Comparison of 3 methods of calculating valve surface by continuous Doppler in the quantitative evaluation of 42 cases of aortic stenosis in adults].

42 patients with a tight, symptomatic aortic stenosis, underwent a Doppler test followed, within approximately 5 days, with catheterization. Non-invasive measurement of the maximal aortic gradient is obtained by applying Bernouilli's formula to the maximum speed. Three methods of evaluation of the valvular areas are compared. The first method derives from Gorlin's formula. The second corresponds to the ratio aortic flow/mean velocity. The third method uses the continuity equation. The results compared with haemodynamic data are as follows: the correlation factor regarding the gradients is: r = 0.72 (EA: 22 mmHg), going from r = 0.74 (EA: 0.11 cm2) for the first method, r = 0.76 (EA: 0.15 cm2) for the second method and r = 0.81 (EA: 0.10 cm2) for the third method. In conclusion, the calculation of the maximum gradients is of good predictive value to differentiate minimal and tight aortic stenoses. Regarding moderate or decompensated aortic stenoses, it is advisable to follow the Doppler with the measurement of the valvular areas. The first two methods are characterized by their practicality and easy realization; the third method is preferable when there is an associated mitral valve disease.