A Comparative Analysis of the Mechanical Properties of Aortic Aneurysms Samples Across Different Pathologies
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Aortic aneurysms result from complex interactions between genetic predisposition, hemodynamic forces, and progressive extracellular matrix degradation. Characterizing their mechanical behavior is critical for improving rupture risk assessment and enhancing patient-specific biomechanical models. This study investigates regional mechanical differences in thoracic aortic aneurysms across major pathological conditions, including Marfan and Loeys–Dietz syndromes (MFS/LDS), familial aneurysms, bicuspid aortic valve (BAV), and degenerative disease. Anterior and posterior aortic wall specimens were obtained from patients undergoing elective surgical repair. Samples were subjected to standardized uniaxial and biaxial tensile testing to quantify stiffness, extensibility, and nonlinear stress–stretch responses. Mechanical parameters were extracted through curve fitting and stratified by pathology to identify disease- and region-specific mechanical signatures. Uniaxial stress–stretch responses revealed marked intergroup variability. MFS/LDS tissues exhibited reduced toe-region compliance and an early transition to high-stiffness regimes, consistent with elastin impairment. Familial aneurysms showed intermediate mechanical behavior, while degenerative samples demonstrated reduced extensibility with delayed stiffening. BAV-associated aneurysms displayed heterogeneous and multimodal responses. Across all pathologies, anterior wall regions consistently exhibited higher stiffness and lower stretch than posterior regions at comparable stress levels, indicating pronounced regional mechanical asymmetry. These findings suggest that aneurysm evolution is governed by both pathology-specific remodeling mechanisms and region-dependent loading conditions. Incorporating spatially resolved mechanical properties into computational models may improve patient stratification and enhance predictions of aneurysm progression and rupture risk.