Three-dimensional echocardiography in valvular heart disease.

Two-dimensional echocardiography (2DE) with color Doppler has been the standard tool for assessing valvular heart disease. However, this requires conceptualizing three-dimensional (3D) valvular anatomy from individual 2D slices, which is inadequate for complex valvular abnormalities. Similarly, Doppler-based methods are inherently limited by several assumptions and are influenced by hemodynamics and concomitant valvular disease. 3DE has improved both morphological and functional assessment of valvular heart disease. It provides additional morphological information, which leads to better understanding of the mechanism of valvular dysfunction and surgical planning. 3D planimetry has proven to be accurate in the evaluation of valvular stenosis. This direct assessment eliminates measurement errors and could potentially serve as new gold standard. The continuity equation for aortic stenosis can be simplified by directly measuring left ventricular outflow tract area and stroke volume. In patients with valvular regurgitation, vena contracta area can be directly measured by using 3D color Doppler which is more accurate than the standard 2D methods. By applying hemi-elliptical formula or directly measuring isovelocity surface area, 3DE has significantly improved the accuracy in regurgitant severity assessment. This is particularly useful in patients with eccentric jets. 3DE has an advantage over 2DE in assessment of tricuspid valve due to its complex geometry. Direct planimetry of orifice area in tricuspid stenosis, or vena contracta area in tricuspid regurgitation are promising although validation studies are needed before they can be applied for clinical decision making. 3DE has not been widely studied in pulmonic valve disease but preliminary data indicate that it is feasible.