In order to determine a good proximal landing zone and suitable aortic size for the most proximal Thoracic Endovascular Aortic Repair (TEVAR), the dynamic segmental architecture of the entire Ascending Aorta (AA) was examined. The complete AA was imaged using Electrocardiogram Gated-Computed Tomography Angiography (ECG-CTA) in the systolic and diastolic phases in patients with a non-operated AA (diameter 40 mm). The maximum and smallest diameters in the systole and diastole phases for each plane of each segment were noted. Aortic size measurements were compared using the Wilcoxon signed rank test. 100 patients in total (53% men, 82.1 years old on average, 76.8-85.1) were enrolled. Systolic values for the AA during the cardiac cycle were significantly greater than diastolic values, according to analysis of the dynamic plane dimensions of the AA. Analysis of the proximal AA segment revealed a reversed funnel structure, with bigger distal plane values than proximal plane values (p 0.001). The dynamic values at the mid-ascending segment showed a cylindrical shape since there was little difference between the proximal and distal segmental planes. The proximal plane values were greater than the distal segmental plane values at the distal segment of the AA (p 0.001), resulting in a funnel shape.
Conclusions: Throughout the cardiac cycle, the whole AA displayed larger systolic than diastolic aortic dimensions. When a typical cylindrical endograft was used, the midascending and distal-ascending portions displayed favourable shapes for Tevar. Since the most proximal segment of the AA had a clearly conical shape, a particular endograft design should be taken into account.