A method for mechanical characterization of small blood vessels and vascular grafts

For small animal vascular disease models and for the development of small-diameter vascular prosthesis, biomechanical data is important. However, these tiny structures with low diameter (< 1 mm) require special handling and testing. To allow investigation of a high sample number, a custom designed, easy probe fixation was connected to a tensile testing system. In hoop tensile measurements, ring-shaped specimens were loaded circumferentially via two pins. The setup was used for an atherosclerosis experiment in mice where 238 ring-samples of thoracic aortae were tested. Significantly higher ultimate tensile force (413 +/- 123mN) and aortic stiffness (34.3 +/- 4.3 N/m) were seen in atherosclerotic group, compared to control group (347 +/- 108mN and 31.5 +/- 3.8 N/m). Mechanical properties also varied in both groups along the aorta, with tendency to increased strength and higher stiffness in distal locations. A sensitive preparation and measurement technique has been developed for the characterization of very small tubular specimens.