[Mechanical properties of the arteries. Effects of cryopreservation]

The viscoelastic properties of the arterial wall are responsible for the blood pressure wave propagation throughout the arterial system. Arterial diseases may cause disorders in this propagation. We have developed a mock circulation system that allows assessment of viscoelastic properties in fresh or cryopreserved human arteries. It includes the following components:--a hydrodynamic generator that can simulate physiological pressure variations in fresh segments of human arteries;--a lightweight miniature flexible probe that can be placed around the artery to measure changes in the external diameter during systolo-diastolic cycles;--a computer program to analyse pressure and diameter data measured during a cardiac cycle. Using this system, it is possible to evaluate the main viscoelastic properties of the arterial wall (arterial compliance, arterial stiffness, midwall aortic stress, Young elastic modulus, incremental modulus). Human arterial samples were collected during organ harvesting in subjects from 18 to 35 years of age. Correlation between viscoelastic properties, arterial wall status, and histological aspect in nitrogen vapor (-140 degree C) were established. No statistically significant difference was observed in femoral arteries characteristics. Compliance decreased, while stiffness increased with statistically significant difference after cryopreservation in carotid arteries. No histological difference was observed in both arteries before and after cryopreservation.