Usefulness of real-time three-dimensional echocardiography in evaluating aortic root diameters during a cardiac cycle.

Background: The preoperative evaluation of aortic root diameters is important for determining the surgical strategy in patients with aortic valve disease. The purpose of this study was to evaluate the usefulness of real-time three-dimensional echocardiography (3D-echo) for the evaluation of aortic root diameters compared with two-dimensional echocardiography (2D-echo) and to evaluate aortic root dynamics.

Methods: We prospectively investigated 23 patients with aortic stenosis (AS) and 37 normal controls. With 2D-echo, aortic root diameters were measured from the parasternal long-axis view. With 3D-echo, long-axis and short-axis views of the aortic root were reconstructed from the full-volume image, and aortic root diameters were measured at mid-systole, end-systole, mid-diastole, and end-diastole. These aortic root diameters were compared between 2D and 3D measurements, regarding intraoperative and computed tomographic measurements as the gold standard. In addition, dynamic changes of aortic root diameters during a cardiac cycle were evaluated.

Results: Aortic root diameters measured by 3D-echo were larger than those measured by 2D-echo (annular diameter 19.6 ± 2.1 vs. 21.2 ± 2.2 mm, p < 0.0001), and 3D measurements were closer to intraoperative and computed tomographic measurements than 2D measurements. The diameter of the aortic annulus increased during diastole, but the changes during a cardiac cycle were significantly smaller in patients with AS than in normal controls (2.0 ± 2.2 vs. 7.8 ± 3.4%, p < 0.0001).

Conclusions: Aortic root diameters can be more accurately measured by 3D-echo than 2D-echo. Dynamic change of the aortic annulus during a cardiac cycle was smaller in patients with AS. 3D-echo is useful for the quantitative evaluation of the aortic root, including dynamics during a cardiac cycle.