Abstract 13313: Risk of Atherosclerosis in Thoracic Aortic Disease: A Study of Multi-Modal Imaging Data From 40,479 UK Biobank Participants

Background: Despite some shared risk factors, aortic aneurysms and atherosclerosis manifest differently across the aorta. While atherosclerosis commonly co-exists with descending and abdominal aortic aneurysms, some observations suggested a decreased risk of atherosclerosis in patients with ascending aortic aneurysms. This has led to the suggestion that drivers of ascending aortic aneurysms may be anti-atherogenic.

Aim: Using carotid intima-media thickness (cIMT) as a surrogate for atherosclerosis and deep learning-derived estimates of aortic diameter, this study examines whether ascending aortic aneurysms are protective against atherosclerosis in a longitudinal analysis of UK Biobank participants.

Methods: Individuals who underwent both carotid ultrasound and cardiovascular MRI in the UK Biobank (N=40,479) were identified. We derived ascending and descending aortic measurements from a previously developed deep learning model that was trained to quantify dimensions in >4 million MRI images and extract diameter during ventricular systole. Measures of mean cIMT at 2 standardized angles for bilateral carotid arteries were utilized. The relationship between cIMT and aortic diameter was assessed using univariable and multivariable linear regression. β was calculated as μm change in cIMT per cm of aortic diameter.

Results: In individuals with an aneurysmal ascending aorta (

4.5cm), there was no significant association between aortic diameter and cIMT after accounting for age, sex, height, and weight (adjusted β=-15.4, P=0.26). There was also no significant correlation between ascending aortic diameter at baseline and cIMT progression in follow-up (adjusted β=-2.5; P=0.48). In the entire cohort, larger ascending aortic size was nominally associated with greater cIMT (adjusted β=5.0; P=0.005). As expected, larger diameter in the descending thoracic aorta was associated with higher cIMT (adjusted β=23.9; P=1.9x10 ^-16 ).

Conclusion: Based on multi-modal imaging data from over 40K individuals, we find no evidence of an inverse relationship between ascending aortic aneurysmal disease and atherosclerosis.