Real Time Triplane Echocardiography in Aortic Valve Stenosis: Validation, Reliability, and Feasibility of a New Method for Valve Area Quantification

Abstract

The aim of the study was to validate a novel formula for aortic valve area (AVA) based on the principle of continuity equation, that substitutes Doppler-derived stroke volume (SV) by SV directly measured with real time simultaneous triplane three-dimensional echocardiography (RT3P). RT3P has proved accuracy for left ventricular volume calculation. So far, however, neither this potential has been applied to hemodynamic assessment, nor RT3P has succeeded in the evaluation of aortic valve disease. AVA was measured in 21 patients with aortic stenosis using Gorlin's equation, Doppler continuity equation (two-dimensional echocardiography), the novel RT3P method, and by substituting Doppler-derived SV by SV measured with two-dimensional stroke volume (2DSV). RT3P has the best linear association (R(2)= 0.61) and the best correlation with Gorlin of all noninvasive methods (even if not statistically significant). RT3P carries significantly lower mean differences with catheterization, as compared with 2D and 2DSV (Table 4). Standard deviations of mean differences between RT3P and catheterization and between the other echocardiographic methods are not statistically different, even if RT3P seems to be nearer to catheterization. Inter- and intraobserver variability were, respectively, 0.03 +/- 0.11 cm(2) and 0.02 +/- 0.03 cm(2), better than 2D and 2DSV. RT3P has revealed to be more accurate than two-dimensional method in AVA quantification, with a better intraobserver agreement. In addition, it allows simple and fast image acquisition.