Effect of Ageing on Arterial Stresses Due to Limb Flexion

Introduction Peripheral artery disease (PAD) frequently refers to atherosclerotic obstruction of the femoropopliteal artery (FPA) reducing blood flow to the lower limb. Segment of the FPA at the Adductor Hiatus (AH) is a... [ view full abstract ]

Introduction Peripheral artery disease (PAD) frequently refers to atherosclerotic obstruction of the femoropopliteal artery (FPA) reducing blood flow to the lower limb. Segment of the FPA at the Adductor Hiatus (AH) is a common site of obstruction likely because it experiences severe mechanical loads during limb flexion. The goal of this work was to study how mechanical stresses occurring at the AH during limb flexion change with age.

Methods: FPA deformations due to acute limb flexion (gardening posture) were quantified using human cadaver model, custom-made nitinol markers, and CT imaging. Mechanical properties and in situ longitudinal prestretch representative of seven age groups were determined with planar biaxial testing and constitutive modeling of fresh human FPAs (n=579) from 13-82 year old donors. Finite element analysis of FPA segment at AH loaded through a series of soft springs to account for the different bent configurations in each age group was employed to quantify intramural principal mechanical stresses due to limb flexion.

Results: Youngest age group (10-19 years old) experienced the lowest principal stresses of 38.6 kPa. Stresses increased 15% in 20-39 year old FPAs, 50% in 40-49 year old arteries, and 200-306% in FPAs older than 50 years old.
Discussion: Significant increase in limb flexion induced mechanical stresses in the FPA with age can contribute to injury and disease frequently observed at AH in older subjects. Studies of intramural stresses in the FPA due to limb flexion in the context of ageing can inform better design of devices and materials for PAD.