Ascending aortic geometry and its relationship to the biomechanical properties of aortic tissueCentral MessagePerspective

Abstract

Objective: The objective of this study was to evaluate the relationship between ascending aortic geometry and biomechanical properties. Methods: Preoperative computed tomography scans from ascending aortic aneurysm patients were analyzed using a center line technique (n = 68). Aortic length was measured from annulus to innominate artery, and maximal diameter from this segment was recorded. Biaxial tensile testing of excised tissue was performed to derive biomechanical parameters energy loss (efficiency in performing the Windkessel function) and modulus of elasticity (stiffness). Delamination testing (simulation of dissection) was performed to derive delamination strength (strength between tissue layers). Results: Aortic diameter weakly correlated with energy loss (r2 = 0.10; P 55 mm (n = 33) demonstrated higher energy loss than those 110 mm (n = 37) did not exhibit a difference in energy loss (P = .40), modulus of elasticity (P = .69), or delamination strength (P = .68) compared with aortas <110 mm (n = 31). Aortas above diameter and length thresholds (n = 21) showed no difference in energy loss (P = .35), modulus of elasticity (P = .55), or delamination strength (P = .61) compared with smaller aortas (n = 47). Conclusions: Aortic geometry poorly reflects the mechanical properties of aortic tissue. Weak association between energy loss and diameter supports intervention at larger diameters. Further research into markers that better capture aortic biomechanics is needed.

Keywords

• ascending aorta
• aneurysm
• dissection
• aortic biomechanics