Background: Assessment of the mechanical properties of human arteries after cryopreservation processing protocol including antibiotic sterilisation and controlled freezing with the use of cryoprotector (10% DMSO).
Material and methods: 12 aortic and 9 femoral artery segments were investigated; the donor age ranged from 18 to 42 years, the time of the storage in the liquid nitrogen vapours was from 1 to 36 months. The stretching tests of vessel specimens (using INSTRON tensile testing machine) and manometric investigations were performed. The mechanical resistance (breaking stress) and elastic moduli were evaluated (at maximal stress value and at the stress of 300 kPa). The results were compared with fresh homograft specimens.
Results: The mechanical resistance (breaking stress) of the investigated cryopreserved aortic segments ranged from 1.5 MPa (± 0.34) (if stretched perpendicular to the vessel long axis) to 1.05 MPa (± 0.3) (if stretching was performed in parallel). For the femoral artery specimens the respective values were 2.4 MPa (± 0.93) and 1.35 MPa (± 0.5). Elastic moduli at the stress of 300 kPa in aortic specimens achieved 1.38 (± 0.4) and 1.8 (± 0.85). For the attained femoral arteries respective values were 2.83 (± 1.34) and 1.47 (± 0.9). There were no significant differences concerning mechanical properties between fresh and cryopreserved aortic wall segments.
Conclusions: 1. Cryopreserved allogenic arteries (aorta, femoral arteries) maintain high mechanical resistance against breaking stress and intra-arterial pressure. 2. Despite vessel preparation (including sterilisation and control freezing protocols), cryopreserved arteries maintain elastic properties, justifying an implementation of this material in human circulatory system. 3. The use of arterial segments with low number of collaterals and their correct suture or ligation can influence the allograft mechanical stress resistance.