Determination of Interlayer Stress of Descending Porcine Aorta via Mechanical Testing
Many aortic diseases are accompanied by characteristic changes in the structure, and thus internal mechanical properties, of the aortic wall. One such disease is aortic dissection, which occurs when a tear is formed in the aortic wall that blood can enter. This tear is propagated due to pressure from the blood and will grow inasmuch as the pressure can overcome the energy holding the layers together.
This project analyzed circumferential and axial samples from porcine descending aortas to explore how internal stress differs across the wall. Dimension and opening angle measurements were taken along with uniaxial testing. The samples were then peeled into two layers, each of which underwent opening angle and uniaxial analysis. Uniaxial data was fit to a nonlinear elastic model, and the peeled layers were compared to see if dimensions and opening angle differed due to relieving of internal stress from the peeling process. These data were then fed into an FEBio model to see if the opening angle behavior could be recapitulated.
This work adds some additional complexity to models of aortic structure and mechanics and may be useful in predicting or describing the progression of diseases such as aortic dissection.