Mechanical instability of normal and aneurysmal arteries

Area of Science:

• Biomechanics
• Cardiovascular Research
• Medical Engineering

Background:

• Tortuous arteries and aneurysms are common in aging patients with atherosclerosis and hypertension.
• The mechanisms linking these conditions remain unclear.
• Arterial buckling instability is a potential contributing factor.

Purpose of the Study:

• To investigate the impact of aneurysms on arterial buckling.
• To determine how buckling affects aneurysm wall stress.
• To elucidate the relationship between artery buckling and aneurysms.

Main Methods:

• Computational simulations of normal and aneurysmal carotid arteries and aortas.
• Experimental buckling tests on porcine carotid arteries with induced aneurysms.
• Finite element analysis of aneurysm models with orthotropic nonlinear elastic walls.

Main Results:

• Arteries buckle at a critical pressure, with post-buckling deflection increasing nonlinearly.
• Aneurysms can lower the critical buckling pressure, depending on their size.
• Buckled aneurysms experience higher peak wall stress than unbuckled ones under similar pressure.

Conclusions:

• Aneurysmal arteries are susceptible to mechanical buckling.
• Mechanical buckling can elevate stress within aneurysm walls.
• Buckling may explain the formation of tortuous aneurysmal arteries, as seen in Loeys-Dietz syndrome.