Reference Values for Mid-Ascending Aorta Diameters by Transthoracic Echocardiography in Adults

We sought to characterize mid-ascending aorta diameter reference values by age, sex, and body surface area (BSA) in a large echocardiography laboratory practice-based cohort. All subjects with transthoracic echocardiograms with mid-ascending aorta diameter measure from January 2004 to December 2009 were identified, and medical records were reviewed for medical history and anthropometric data. Those with aortic valve disease or replacement, congenital heart disease, any connective tissue or inflammatory disease that may affect the aorta, or known aortic aneurysm (>55 mm) were excluded. Mid-ascending aorta diameter was measured in a standardized manner using "leading edge to leading edge" technique at end-diastole. Of 27,839 eligible subjects, 16,620 did not have history of hypertension and were included in the analysis (56.3% female; mean age 52.0 ± 15.8 years), mean mid-ascending aorta diameter 31.7 ± 4.1 mm. Females had smaller diameter than males (30.5 ± 3.7 mm vs 33.3 ± 4.0 mm; p <0.001). Subjects with history of hypertension (n = 11,219; not included in the analysis) had larger mid-ascending aorta diameter compared with normotensive subjects (33.9 ± 3.8 mm vs 31.7 ± 4.1 mm; p < 0.001). Age had the greatest correlation with aortic size (r = 0.55), followed by sex (r = 0.35) and BSA (r = 0.35). Nomograms for predicted mid-ascending aorta diameter were generated at the 95th percentile using quantile regression for subjects without hypertension stratified by age, sex, and BSA. In conclusion, mid-ascending aorta diameter is predominantly associated with sex, age, and BSA. The nomograms established by this study may serve as useful reference values for echocardiographic screening and surveillance.