Two-dimensional transthoracic echocardiographic normal reference ranges for proximal aorta dimensions: results from the EACVI NORRE study

To report normal reference ranges for echocardiographic dimensions of the proximal aorta obtained in a large group of healthy volunteers recruited using state-of-the-art cardiac ultrasound equipment, considering different measurement conventions, and taking into account gender, age, and body size of individuals.

A total of 704 (mean age: 46.0 ± 13.5 years) healthy volunteers (310 men and 394 women) were prospectively recruited from the collaborating institutions of the Normal Reference Ranges for Echocardiography (NORRE) study. A comprehensive echocardiographic examination was obtained in all subjects following pre-defined protocols. Aortic dimensions were obtained in systole and diastole, following both the leading-edge to leading-edge and the inner-edge to inner-edge conventions. Diameters were measured at four levels: ventricular-arterial junction, sinuses of Valsalva, sino-tubular junction, and proximal tubular ascending aorta. Measures of aortic root in the short-axis view following the orientation of each of the three sinuses were also performed. Men had significantly larger body sizes when compared with women, and showed larger aortic dimensions independently of the measurement method used. Dimensions indexed by height and body surface area are provided, and stratification by age ranges is also displayed. In multivariable analysis, the independent predictors of aortic dimensions were age, gender, and height or body surface area.

The NORRE study provides normal values of proximal aorta dimensions as assessed by echocardiography. Reference ranges for different anatomical levels using different (i) measurement conventions and (ii) at different times of the cardiac cycle (i.e. mid-systole and end-diastole) are provided. Age, gender, and body size were significant determinants of aortic dimensions.