Normal Values and Differences in Ascending Aortic Diameter in a Healthy Population of Adults as Measured by the Pediatric versus Adult American Society of Echocardiography Guidelines

Background: There is a lack of uniformity across echocardiographic society guidelines as to how the diameter of the ascending aorta is to be measured. The aims of this study were to compare measurements done using the diastolic leading edge-to-leading edge and systolic inner edge-to-inner edge (SIE) techniques in a large cohort of healthy adult individuals and to report the normal values for adults using the SIE technique.

Methods: Aortic diameters obtained according to the two guideline recommendations at the aortic annuls, sinuses of Valsalva, sinotubular junction, and ascending aorta in 1,148 healthy adult volunteers were compared. Bland-Altman analysis, paired t tests, and intraclass correlation coefficients were evaluated at each segment. SIE values are reported as normative data, according to age, gender, and body surface area.

Results: The diastolic leading edge-to-leading edge convention yielded smaller diameters (compared with SIE) at the aortic annulus and ascending aorta and larger diameters at the sinus of Valsalva and sinotubular junction (P < .001 for all). There was excellent correlation between these techniques, with intraclass correlation coefficients of 0.88 to 0.96. Interobserver variability was minimal and similar for both techniques. Using the SIE technique, diameters were larger for men and increased with age and larger body surface area.

Conclusions: Although there was a statistically significant difference in aortic diameter measures between the two conventions used, this difference was very small and correlations were excellent, suggesting that the difference has no clinical significance. The authors recommend that a standard convention be adopted within the American Society of Echocardiography and across all professional cardiovascular imaging societies for consistency and improved communication.