Biomechanics of Aortic Dissection: A Comparison of Aortas Associated With Bicuspid and Tricuspid Aortic Valves

Aneurysmal ascending aortas were collected from elective aortic surgery, and normal aortas from transplant donors, and dissected aortas from surgery for aortic dissection. These aortas underwent delamination testing in simulation of aortic dissection. Biaxial tensile testing was performed to determine modulus of elasticity (aortic stiffness), and energy loss (a measure of efficiency in performing the Windkessel function). Delamination strength (Sd) was lowest in dissected aortas and highest in normal aortas, and aneurysms fell in between, with greater Sd in the BAV group than the TAV group (P<0.001). Bicuspid aortopathy was associated with greater stiffness (P<0.001), while aneurysms with TAV demonstrated greater energy loss (P<0.001). Increased energy loss was associated with decreased Sd, whereas there was no relationship between Sd and aortic stiffness.

Aneurysms with bicuspid aortic valve had higher delamination strength than those with tricuspid aortic valve, suggesting that bicuspid aortic valve was protective. Energy loss was lower in aneurysms with bicuspid aortic valve, and inversely associated with delamination strength, representing a potential novel biomarker.