Quantitative analysis of mitral annular geometry and function in healthy volunteers using transthoracic three-dimensional echocardiography

BACKGROUND: Quantitative assessment of the mitral annulus provides information regarding the pathophysiology of mitral regurgitation and aids in the planning of reparative surgery. Three-dimensional (3D) transthoracic echocardiographic data sets acquired with current scanners have enough spatial and temporal resolution to allow the quantitative analysis of the mitral annulus. Accordingly, the authors performed (1) a validation study to assess the agreement of quantitative analysis of the mitral annulus performed on 3D transthoracic echocardiography (TTE) and 3D transesophageal echocardiography (TEE) and (2) a normative study to obtain the reference values of 3D transthoracic echocardiographic parameters for mitral annular (MA) geometry and dynamics. METHODS: Mitral valve data sets were obtained by 3D TEE and 3D TTE in 30 consecutive patients with clinically indicated TEE (validation study) and 3D TTE in 224 healthy volunteers (aged 18-76 years) (normative study). RESULTS: In the validation study, MA measurements obtained by 3D TTE were similar to those obtained by 3D TEE (P = NS). In the normative study, MA analysis by 3D TTE was feasible (94.5%) and reproducible (intraclass correlation coefficient = 0.78-0.97). MA diameters, area, and circumference were correlated with body surface area (r > 0.50 for all) but not with age. Men had larger MA areas than women (4.9 ± 1.0 vs 4.5 ± 0.7 cm(2)/m(2), P = .004). During systole, MA area decreased by 29 ± 5%. This decrease was related mainly to anteroposterior diameter shortening (20 ± 7%). CONCLUSIONS: MA quantitative analysis by 3D TTE was accurate compared with 3D TEE in unselected patients with mitral valve disease. In healthy subjects, it was highly feasible and reproducible. The availability of reference values for MA geometry and dynamics may foster the implementation of MA quantitative analysis by 3D TTE in clinical settings.