Abstract 9061: Aortic Wall Stress Across Risk Groupings of Aortic Size and Height Indices in a Male Veteran Population With Ascending Thoracic Aortic Aneurysm

• Published in: Circulation (New York, N.Y.) N.Y.), 2021-11, Vol.144 (Suppl_1), p.A9061-A9061
• Main Authors: Zamirpour, Siavash, Xuan, Yue, Wang, Zhongjie, Gomez, Axel, Hope, Michael D, Leach, Joseph, Saloner, David A, Guccione, Julius M, Ge, Liang, Tseng, Elaine E
• Format: Article
• Language: English
• ISSN: 0009-7322; 1524-4539
• DOI: 10.1161/circ.144.suppl_1.9061

IntroductionNatural history studies of ascending thoracic aortic aneurysm (aTAA) identified maximum diameter as a predictor of aortic dissection, informing guidelines for prophylactic surgery. Studies have since challenged the biomechanical basis of diameter-based risk assessment. Indices of diameter with measures of body size were proposed to account for individual variation in diameter, including body surface area as aortic size index (ASI) or height as aortic height index (AHI). The goal of this study was to determine differences in aneurysm wall stresses across previously defined clinical risk groups for ASI and AHI. MethodsHeight and weight measurements were retrospectively reviewed for 264 male veterans with aTAA. Wall stresses were previously simulated using finite element analyses on patient-specific geometries. Group differences in wall stress were assessed among ASI and AHI risk groups using the Kruskal-Wallis and Dunn tests. ResultsMedian ± interquartile range circumferential stresses among ASI risk groups were 486.5 ± 132.8, 510.7 ± 140.5, and 617.2 ± 201.6 kPa for groups 1-3 (P = .19). Longitudinal stresses were 307.3 ± 70.8, 300.8 ± 67.9, and 359.1 ± 57.2 kPa (P = .09). Among AHI risk groups, circumferential stresses were 476.9 ± 151.4, 503.3 ± 135.4, and 586.2 ± 102.6 kPa for groups 1-3 (P = .008). Longitudinal stresses were 297.6 ± 80.7, 304.1 ± 64.7, and 361.2 ± 122.9 kPa (P = .004). For both circumferential and longitudinal stresses, pairwise comparisons were significant between groups 1,3 and 2,3. No observations were classified as group 4 for ASI or AHI. ConclusionsDifferences in wall stress were not significant across ASI risk groups and were significant between AHI groups 1,3 and 2,3. While both indices have been shown to stratify clinical outcomes, AHI-based risk groups may better reflect differences in biomechanical state. Prospective studies may further elucidate the relationship between biomechanical status and clinical outcomes.