Noninvasive quantification of the aortic valve area in aortic stenosis by Doppler echocardiography

To develop a noninvasive approach to the quantification of thestenotic aortic valve area, Doppler echocardiography and cardiaccatheterisation were performed in 24 patients with pure aorticstenosis. The transmitral volumetric flow was measured by Dopplerechocardiography and calculated as the product of the correctedmitral orifice area (CM A) and the diastolic velocity integral(DVI). The maximal aortic jet velocities were recorded by Dopplertechnique and integrated to obtain the systolic velocity integral(SVl). Assuming that the aortic and mitral volumetric flowsare equal, the aortic valve area (A VA) was calculated as: AVA= CM A x DVI/SVI. Mean pressure gradient and cardiac outputwere measured during catheterisation and the aortic valve areawas calculated by the Gorlin formula. Comparison between theaortic valve area determined by Doppler technique and catheterisationyielded a close correlation (r = 0.92, P<0.001), and therewas no significant difference between the two measurements.Good correlations of the instantaneous pressure gradient andthe stroke volume were also obtained between the two techniques(r = 0.91 and r = 0.90, respectively, P<0.001). These resultsdemonstrate that our Doppler echocardiographic method providesa promising approach to the noninvasive quantification of theaortic valve area in aortic stenosis