Thoracic aortic geometry correlates with endograft bird-beaking severity

Objective: Aortic geometry has been shown to influence the development of endograft malapposition (bird-beaking) in thoracic endovascular aortic repair (TEVAR), but the extent of this relationship lacks clarity. The aim of this study was to develop a reproducible method of measuring bird-beak severity and to investigate preoperative geometry associated with bird-beaking. Methods: The study retrospectively analyzed 20 patients with thoracic aortic aneurysms or type B dissections treated with TEVAR. Computed tomography scans were used to construct three-dimensional geometric models of the preoperative and postoperative aorta and endograft. Postoperative bird-beaking was quantified with length, height, and angle; categorized into a bird-beak group (BBG; n = 10) and no bird-beak group (NBBG; n = 10) using bird-beak height ≥5 mm as a threshold; and correlated to preoperative metrics including aortic cross-sectional area, inner curvature, diameter, and inner curvature 7 diameter as well as graft diameter and oversizing at the proximal landing zone. Results: Aortic area (1002 \ub1 118 mm2 vs 834 \ub1 248 mm2), inner curvature (0.040 \ub1 0.014 mm−1 vs 0.031 \ub1 0.012 mm−1), and diameter (35.7 \ub1 2.1 mm vs 32.2 \ub1 4.9 mm) were not significantly different between BBG and NBBG; however, inner curvature 7 diameter was significantly higher in BBG (1.4 \ub1 0.5 vs 1.0 \ub1 0.3; P =.030). Inner curvature and curvature 7 diameter were significantly correlated with bird-beak height (R = 0.462, P =.041; R = 0.592, P =.006) and bird-beak angle (R = 0.680, P <.001; R = 0.712, P <.001). Conclusions: TEVAR bird-beak severity can be quantified and predicted with geometric modeling techniques, and the combination of high preoperative aortic inner curvature and diameter increases the risk for development of TEVAR bird-beaking