Abstract 16846: Three-Dimensional Assessment of Ascending Aortic Motion by Dynamic CT in Sporadic and Marfan Thoracic Aortic Aneurysm

Abstract

Background: The ascending aorta exhibits a complex, 3D motion related to cyclic pressure changes and downward traction forces related to left ventricular contraction. However, most metrics of disease severity are static (i.e., diameter) and among prior studies that have investigated ascending aortic motion, 2D imaging is typically employed. Vascular deformation mapping (VDM) is an image analysis technique that accurately quantifies 3D displacement of the aortic wall. Aims We aimed to quantify 3D metrics of cyclic ascending aortic motion and distensibility in patients with aTAA, and evaluate associations between motion metrics and patient characteristics in sporadic TAA (SaTAA) and Marfan syndrome (MFS). Methods: We included adult patients with aTAA, either SaTAA or MFS, and multi-phasic CTA of the thoracic aorta. VDM analysis of CTA data was performed with metrics including: 1) Axial, in-plane and rotational displacements at the root, 2) distensibility assessed by cyclic 2D cross-sectional area change (Dist-2D) at the root [(ΔA/A diastole х PP)], and 3) distensibility assessed by VDM-derived cyclic surface area stretch [(Area ratio-1)*1/PP] at the root and tubular ascending (Dist-3D). Aortic growth rate (GR) was measured from follow-up CTA. Results: We analyzed 51 with SaTAA (33% female, 62 ± 11 years old), and 14 with MFS (50% female, 42 ± 13 years old). In SaTAA, Dist-2D was associated (β=0.59, p=0.047) with axial displacement and AI was strongly associated (β=1.03 p=0.001) with rotation. In MFS, BAV and diameter were associated with in-plane displacement (β=5.50, p=0.004; β=-0.026, p=0.001). Among MFS patients with follow-up CTAs (n=10), ascending distensibility (Dist-3D) was marginally negatively associated with ascending GR (β= -0.27, p=0.058) Conclusion: 3D analysis of aortic motion in aTAA showed differences in root motion, namely related to valve disease and age, as well as differences in aortic distensibility that may predict ascending aortic GR in MFS.