Dilation of the Proximal Thoracic Aorta in an Asymptomatic Primary Prevention Population Undergoing Noncontrast Chest Computed Tomography
Authors: Alaa Alashi, Richard Lang, Raul Seballos, Steven Feinleib, Roxanne Sukol, Eric E Roselli, Lars G. Svensson, Vidyasagar Kalahasti, Paul Schoenhagen, Scott D. Flamm, Brian P. Griffin, Milind Y. Desai
Journal: Circulation (2019)

◼ primary prevention T horacic aortic aneurysm is a potentially devastating disease that kills by dissection/rupture and exsanguination. 1However, it is difficult to estimate the true prevalence because many aneurysms are clinically silent and present as sudden death.Death by thoracic aortic aneurysm in the United States occurs at a rate of 3.1 (2.5 for women and 3.7 for males) per 100 000. 1 In recent years, reduction in mortality is likely related to improved surveillance and surgical techniques. 2 However, there remains a need for earlier detection.We sought to assess the rate of incidentally detected proximal ascending aortopathy in asymptomatic middleage executives undergoing coronary artery calcium scoring at our institution.This was an observational study of 1806 consecutive asymptomatic executives undergoing a comprehensive evaluation in a primary prevention clinic between March 2016 and September 2017 after institutional review board approval with waiver of individual consent.No patient had documented aortic valve disease or aortopathy.Subjects underwent a prospectively triggered, axial noncontrast cardiac computed tomography scan (3 mm slice thickness, Siemens or Philips scanner).Along with coronary artery calcium scoring, aortic root (AR, measured cusp to commissure)and ascending aortic (AA) dimensions were measured using multiplanar reformatting. 3For both AR and AA, aortic size index (cm/m 2 , dimensions/body surface area) and aortic height index (AHI, cm/m 2 , aortic dimensions/height) were calculated. 4AR Z score was also calculated: measured diameter (cm)-predicted diameter (cm)/0.261. 5Predicted diameter was derived as: 2.423+(agex0.009)+(bodysurface areax0.461)-(sexx0.267), 1 for male and 2 for female.Thoracic aortic calcification (none severe) was recorded. 3Continuous variables are reported as mean±SD or median with interquartile range.Categorical variables are reported as percentage.Logistic regression analysis was performed to test the association between dilated aorta (AR or AA AHI >2.43 cm/m 2 ) and potential predictors. 4 Baseline characteristics are shown in the Table, and CAC distribution was as expected.Dilated (>4 cm) AR and AA were observed in 346 (19%) and 183 (10%) participants, respectively (37 [2%)] had both dilated AR and AA).Three patients (0.2%) had both AR and AA >4.5 cm, none ≥5.5 cm.AR and AA ASI were high (>2.05cm/m 2 ) in 375 (21%) and 263 (15%) participants, respectively (226 [13%] had both AR and AA ASI >2.05 cm/m 2 ). 4 Similarly, AR and AA AHI were high (>2.43 cm/m 2 ) in 285 (16%) and 223 (12%) participants, respectively (178 [10%] had both AR and AA AHI >2.43 cm/m 2 ). 4 AR Z score ≥2 was observed in 142 (8%) participants.Age (odds ratio, 1.02; 95% CI, 1.016-1.024),sex (odds ratio, 1.43; 95% CI, 1.13-1.82),body surface area (odds ratio, 1.01; 95% CI, 1.006-1.014),and hypertension (odds ratio, 1.29; 95% CI, 1.02-1.65)were independently associated with high AR and AA AHI (all P<0.01).On echocardiography, 8 participants had a bicuspid aortic valve and dilated AR.