Biomechanics of aortic wall failure with a focus on dissection and aneurysm: A review

Abstract

Aortic dissections and aortic aneurysms are fatal events characterized by structural changes to the aortic wall. The maximum diameter criterion, typically used for aneurysm rupture risk estimations, has been challenged by more sophisticated biomechanically motivated models in the past. Although these models are very helpful for the clinicians in decision-making, they do not attempt to capture material failure. Following a short overview of the microstructure of the aorta, we analyze the failure mechanisms involved in the dissection and rupture by considering also traumatic rupture. We continue with a literature review of experimental studies relevant to quantify tissue strength. More specifically, we summarize more extensively uniaxial tensile, bulge inflation and peeling tests, and we also specify trouser, direct tension and in-plane shear tests. Finally we analyze biomechanically motivated models to predict rupture risk. Based on the findings of the reviewed studies and the rather large variations in tissue strength, we propose that an appropriate material failure criterion for aortic tissues should also reflect the microstructure in order to be effective.

Roles and Mechanisms of Interleukin-12 Family Members in Cardiovascular Diseases: Opportunities and Challenges

“…Aortic aneurysms and aortic dissection are both degenerative lesions of the aorta and share the same pathological mechanisms, such as the excessive loss of aortic extracellular matrix mediated by multiple pathological factors, especially local aortic inflammation (Mallat et al, 2016;Rabkin, 2017;Raffort et al, 2017;Sherifova and Holzapfel, 2019).…”

Investigation of Pathophysiological Aspects of Aortic Growth, Remodeling, and Failure Using a Discrete-Fiber Microstructural Model

“…Since tissue failure-either by rupture or dissection-is the major clinical threat associated with pathological vessel growth, we looked at two failure scenarios for the MLUs: a strip biaxial and a shear to failure. Each failure scenario treated the test as a passive failure test (as in experiments [51][52][53][54][55][56][57]) so the actin contractility was removed. The strip biaxial test was meant to serve as an analog for the burst failure of the artery.…”

Predictors of Abdominal Aortic Aneurysm Risks

“…The anatomy of an AAA is markedly different than the normal abdominal aorta. AAA walls are frequently associated with degradation of the wall microstructure including the elastic lamellae, paucity of smooth muscle cells, and loss of the three distinct aortic layers [ 29 , 30 ], and thus, abnormal tissue properties [ 5 ]. Another common finding in pathological AAA wall tissue is the presence of localized calcified regions [ 31 ].…”

“…Abdominal aortic aneurysm (AAA) is a potentially life-threatening condition, characterized as a pathological expansion of the abdominal aorta, wherein the maximal transverse diameter exceeds 30 mm [ 1 , 2 , 3 ]. Aneurysm rupture, by definition, occurs when aortic wall stress exceeds aortic wall strength [ 4 , 5 ], which is the stress/tension at which the wall can no longer withstand the forces applied to it (e.g., due to blood pressure). Rupture represents the main concern associated with AAA, as AAA rupture carries an overall mortality rate of approximately 80–85% [ 6 , 7 ].…”