Biomechanics of the aortic root and ascending aorta in patients with Marfan syndrome

OBJECTIVES How Marfan syndrome (MFS) translates to alterations in ex vivo biomechanical properties of aortic tissue is not well defined. We aimed to characterize the biomechanical properties of the aortic root and ascending aorta in MFS, and compare them to properties of normal, dissected, and non-MFS aneurysmal aortas. METHODS Biaxial tensile and delamination testing were performed on aortic tissue from patients with MFS (root = 10, ascending = 6), aneurysms with bicuspid aortic valves (BAVs) (root = 19, ascending = 88), aneurysms with tricuspid aortic valves (root = 25, ascending = 90), type A dissections (ascending = 17), and normal aortas (root = 12, ascending = 28). Differences in energy loss, low strain modulus, and delamination strength were investigated between patient groups. RESULTS In the aortic root, energy loss, low strain modulus, and delamination strength were not statistically different in MFS compared to all other groups. In the ascending aorta, delamination strength was lower in MFS than normal ascending aortas (31.9 ± 8.5 mN/mm vs 57.1 ± 17.0 mN/mm, p = 0.0003). The MFS group (0.071 ± 0.017) also had higher energy loss than normal (0.049 ± 0.011, p = 0.04), and lower low strain modulus (75.0 ± 11.0 kPa) than BAV (113.5 ± 33.6 kPa, p = 0.02). CONCLUSIONS The root and ascending aorta in MFS proved to have distinct biomechanical characteristics compared to normal aortas and other risk groups.