Comparative measurement of aortic root by transthoracic echocardiography in normal Korean population based on two different guidelines

Background: Aortic root size is an important parameter in vascular diseases and can be easily assessed by transthoracic echocardiography. However, measurements values may vary according to cardiac cycle and the definition used for edge. This study aimed to define normal values according to the measurement method specified by two different guidelines to determine the influence of the different methods on echocardiographic measurements. Methods. Healthy Korean adults were enrolled. The aortic root diameters were measured twice at four levels (aortic annulus, sinuses of Valsalva, sinotubular junction, and ascending aorta) by the 2005 American Society of Echocardiography (ASE) guidelines (measured from leading edge to leading edge during diastole) and the 2010 ASE pediatric guidelines (measured from inner edge to inner edge during systole). Results: One hundred twelve subjects aged 20-69 years were enrolled. The aortic diameters (cm) determine by the aforementioned two guidelines showed significant difference. Measurements were larger in 2005 ASE guideline at aortic annuls, sinuses of Valsalva, and sinotubular junction level, but smaller at ascending aortic level with 2-3mm of differences. Intraobserver variability was similarly good, but interobserver variability was slightly higher than intraobserver variability in both measurement methods. BSA and age was most important determinant for aortic root size. Conclusions: The measurement method of aortic root can affect the echocardiographic result. The measurement method should be noted when assessing clinical significance of aortic root measurement.