Critical buckling pressure of human abdominal aortic aneurysms (AAA) in the range of physiological pressures and axial strains

S. Stoytchev, S. Nikolov, M. Antonova, M. Nenov

Abstract: Arteries are subjected to significant mechanical loads from internal blood flow and surround tissue tethering; thus their mechanical strength and stability are essential to normal arterial function. The mechanical stability of arteries in the last decade was investigated using animal experimental data only. The present work aims to expand studies to human AAA (abdominal aortic aneurysms) and compare results about the critical buckling pressure with those published in the literature. Preparations from human aneurysmal tissue were harvested by routine reconstructive operation and investigated by specially designed device in order to determine the corresponding stress-strain relation and Young’s modulus. The AAA was assumed as an elastic cylinder whose diameter and length were estimated from CT images; the arterial pressure was taken from recordings during operation. Our simulations demonstrated that the determining factors of the critical pressure were the axial strain, the wall stiffness and the length of the AAA. The major result of the study was that in the physiological range of pressures and axial elongations the AAA is more likely to buckle than to rupture. The current investigation could be a useful tool to determine the critical axial strain needed in vascular reconstructive surgeries and vascular grafting in order to prevent tortuosity or kinking.


Series on Biomechanics, Vol.33, No. 2(2019), 12 - 17

Keywords: Abdominal aorta aneurism; critical buckling pressure; material properties

Date published: 2019-07-17