Accurate noninvasive quantification of stenotic aortic valve area by Doppler echocardiography.

Laminar flow through a conduit is equal to the mean velocity times the cross-sectional area of the orifice. Therefore, volume is equal to the time-velocity integral multiplied by the cross-sectional area. In aortic stenosis, flow in the stenotic jet is laminar and the aortic valve area should be equal to the volume of blood ejected through the valve divided by the time-velocity integral of the aortic jet velocity recorded by continuous-wave Doppler echocardiography. To test whether this concept can be used to accurately determine aortic valve area noninvasively by the Doppler method, 39 patients (age 35 to 82 years, mean 63) underwent pulsed Doppler combined with two-dimensional echocardiography for measurement of stroke volume at the aortic, pulmonic, and mitral anulus as well as continuous-wave Doppler recording of the aortic jet. Aortic valve area determined at cardiac catheterization by the Gorlin equation ranged between 0.4 and 2.07 cm2 (mean 0.89 +/- 0.45). Doppler-derived valve area, determined wit...