Prevalence of dilated mid-ascending aorta in individuals 15 years and older: In search of optimal diagnostic criteria and their effect on the burden of disease

Background: Controversy regarding the definition of the upper limit of normal (ULN) for dilated mid-ascending aorta (mAA) stems from variation in criteria, based on several small-sized studies with small datasets of normal subjects (DONS). The present study was carried out to demonstrate this variation in the prevalence of mAA dilation and to identify the optimal definition by creating the largest DONS. Methods: Echocardiographic studies of patients ≥ 15 years of age performed at a large tertiary care center over 4 years ( n = 49,330) were retrospectively evaluated. The leading-edge-to-leading-edge technique was used to measure the mAA in diastole. The largest-to-date DONS ( n = 2334) was created, including those who were normal on medical record review, did not have any of the 28 causes of dilated aorta, and had normal echocardiograms. Because age had the strongest correlation with mAA (multivariate adjusted R 2 = 0.26), as compared with sex, height, and weight, we created a new ULN based on the DONS with narrow age stratification (10-year intervals). Results: The prevalence of dilated mAA varied between 17% and 23% when absolute criteria were used with sex stratification, and it varied between 6% and 11% when relative criteria (relative to age, body surface area, and sex) were used. Based on new criteria from the DONS, it was 7.6%, with a ULN of 3.07-3.64 cm in women and 3.3-3.91 cm in men. Conclusions: These data demonstrate the undesirable variation in the prevalence of dilated mAA based on prior criteria and propose a new ULN for dilated mAA.