Assessment of aortic stenosis by three-dimensional echocardiography: an accurate and novel approach

Background: Accurate assessment of aortic valve area (AVA) is important for clinical decision-making in patients with aortic valve stenosis (AS). The role of three-dimensional echocardiography (3D) in the quantitative assessment of AS has not been evaluated so far. Objectives: To evaluate the reproducibility and accuracy of real-time three-dimensional echocardiography (RT3D) and 3D-guided two-dimensional planimetry (3D/2D) for assessment of AS, and compare these results with those of standard echocardiography and cardiac catheterisation (Cath). Methods: AVA was estimated by transthoracic echo-Doppler (TTE) and by direct planimetry using transoesophageal echocardiography (TEE) as well as RT3D and 3D/2D. 15 patients underwent assessment of AS by Cath. Results: 33 patients with AS were studied (20 men, mean (SD) age 70 (14) years). Bland-Altman analysis showed good agreement and small absolute differences in AVA between all planimetric methods (RT3D vs 3D/2D: 20.01 (0.15) cm(2); 3D/2D vs TEE: 0.05 (0.22) cm(2); RT3D vs TEE: 0.06 (0.26) cm(2)). The agreement between AVA assessment by 2D-TTE and planimetry was 20.01 (0.20) cm(2) for 3D/2D; 0.00 (0.15) cm(2) for RT3D; and -0.05 (0.30) cm(2) for TEE. Correlation coefficient r for AVA assessment between each of 3D/2D, RT3D, TEE planimetry and Cath was 0.81, 0.86 and 0.71, respectively. The intraobserver variability was similar for all methods, but interobserver variability was better for 3D techniques than for TEE (p<0.05). Conclusions: The 3D echo methods for planimetry of the AVA showed good agreement with the standard TEE technique and flow-derived methods. Compared with AV planimetry by TEE, both 3D methods were at least as good as TEE and had better reproducibility. 3D aortic valve planimetry is a novel non-invasive technique, which provides an accurate and reliable quantitative assessment of AS.