# The structural and microbiological properties of human cadaveric iliac vessel grafts stored at a readily available standard freezer: a comprehensive analysis as a function of storage time

## TL;DR

This study evaluates how long human cadaveric iliac vessel grafts can be stored in a standard freezer without cryoprotectant while maintaining their structural and microbiological quality.

## Contribution

The study introduces a low-cost, readily available storage method for vascular allografts and identifies a 12-month storage limit for optimal graft quality.

## Key findings

- Grafts stored for more than 24 months showed increased morphological changes compared to shorter storage periods.
- Endothelial damage was less severe in grafts stored for less than 12 months.
- No bacterial growth was observed in any of the stored graft samples.

## Abstract

Vascular allografts are very important tool for transplantation procedures especially in living donor liver transplantation (LT). The aim of this study is to evaluate the histopathological and microbiological properties of human cadaveric iliac vessel grafts stored by a readily available method (freezing at −24 °C without using cryoprotectant solution) and to determine the impact of storage time on these parameters.

Donor characteristics, histopathological changes on light microscopy [tunica intima, internal elastic lamina (IEL), tunica media in artery allografts], scanning electron microscopy (SEM) endothelial morphology grade and the microbiological results were recorded.

A total of 54 cadaveric iliac vessel grafts (28 iliac arteries and 26 iliac veins) harvested from 28 donors were grouped based on the storage period as fresh control (0–24 h, n = 10) and 0–6 months (n = 10), 6–12 months (n = 10), 12–24 months (n = 12) and >24 months (n = 12) storage groups. Demographic data of the donors were similar along the groups. Some morphological changes were seen in graft stored for >24 months than those stored shorter time on the histopathological examinations and morphometric analysis. Endothelial structure damage was observed less in the grafts those stored shorter than 12 months than longer time in SEM examination. None of the graft samples showed bacterial growth after incubation.

In conclusion, our findings revealed that iliac vessel allografts stored for less than 12 months had the lower risk of morphological, structural and degenerative endothelial changes. Hence, this simple and readily available low cost storage method seems to offer a favorable alternative in allograft storage up to 12 months.