PhD Scientific Days 2025

Poster Session I. - Y: Surgical Medicine

Multi-scale Mechanics of Cryopreserved Human Arterial Allografts Across a One-year Period

Name of the presenter

Kovács Gergely Imre

Institute/workplace of the presenter

Semmelweis University Dpt. of Vascular and Endovascular Surgery

Authors

Gergely Imre Kovács MD¹, Dóra Haluszka PhD², Evelin Forró PhD², László Hidi M.D. PhD³, Prof. Péter Sótonyi M.D. PhD³

1: Semmelweis University Dpt. of Vascular and Endovascular Surgery
2: Dpt. of Biophysics and Radiation Biology, Semmelweis University
3: Dpt. of Vascular and Endovascular Surgery, Semmelweis University

Text of the abstract

Introduction:
An operation under septic conditions presents significant challenges in vascular surgery: graft infection is a serious risk after synthetic vascular graft implantation. In these complicated cases, an infection-resistant alternative is essential to minimize the chance of reinfection.
Cryopreserved vascular allografts provide a suitable alternative for replacing an infected synthetic graft. Unfortunately, there are no international guidelines for the preparation, storage, or thawing of these vessel grafts.
Based on our decades of clinical experience with allograft use, we have observed a significant increase in the postoperative complication rates when allografts were implanted after more than 6 months of cryogenic storage.

Aims:
We aimed to compare the mechanical properties of cryopreserved arterial allografts over a one-year storage period.

Method:
Human arterial allograft samples explanted during multiorgan donations were frozen in a slow, controlled process using dimethyl sulfoxide. Samples were stored at -80 ˚C. Arteries were examined before cryopreservation (BC), immediately after cryopreservation (C0), and after one year of storage (C52). The extensibility and tensile strength properties were evaluated by uniaxial ring tests, and the elastic modulus was characterized by nanoindentation tests.
The results were analysed by Bland-Altman plots.

Results:
The extensibility between the BC-C0 samples was not remarkable (0.0143 ± 0.29), nor when comparing BC-C52 (0.0957 ± 0.58). The differences between tensile strength values were negligible between fresh and cryopreserved samples: BC-C0 (-0.0325 ± 0.0602 N/mm3) and BC-C52 (-0.0531 ± 0.11 N/mm3).
Regarding the Young’s modulus of cryopreserved arteries, our results showed no difference during the investigation period: BC-C0 (-0.1288 ± 3.14 GPa) and BC-C52 (-0.165 ± 2.80 GPa).

Conclusion:
We found no changes in the mechanical properties during the examination period. Our results indicate that the cryopreserved vascular allografts maintain mechanical stability for up to one year of storage.
The reduced graft patency beyond 6 months of storage is not related to the biomechanical capabilities of the grafts, therefore, further investigation is required to investigate the thrombogenicity, immunogenicity, and biocompatibility of these allografts.

Funding: This research received no funding.