Quantification of aortic valve area using three-dimensional echocardiography

Introduction and objectives. To determine whether the reproducibility of left ventricular outflow tract (LVOT) area measurement is greater with three-dimensional echocardiographic (3D-echo) planimetry than with conventional 2D-echo. To determine the LVOT circularity index by means of 3D-echo. To determine the usefulness of measuring the LVOT area by 3D-echo for quantifying the severity of valvular aortic stenosis. Methods. The study included 40 patients, of whom 22 had an aortic stenosis. The LVOT area was measured using both 2D-echo and 3D-echo, and the circularity index, using 3D-echo alone. In addition, the severity of valvular aortic stenosis was categorized using both 2D-echo and 3D-echo. Results. The levels of inter- and intra-observer agreement on LVOT area measurements were better with 3D-echo. The circularity index was 1.50 (0.25), and there was a very poor linear correlation with LVOT area (r=-0.34; P=.47). Patients with valvular aortic stenosis were categorized according to the severity of their stenoses using both 2D-echo and 3D-echo. The level of agreement between the two techniques was poor (kappa=0.36). Conclusions. Measurements of the LVOT area made using 3D-echo were more reproducible than those made using 2D-echo. Consequently, 3D-echo may be a better technique for assessing the LVOT area. In addition, 3D-echo showed that the LVOT is elliptical in form and that its size is not related to its circularity. Moreover, 3D-echo could also be helpful in classifying the severity of valvular aortic stenosis.