*Purpose: Our objective is to demonstrate that Ex-Vivo Extremity Perfusion (EVEP) of a Vascularized Composite Allograft (VCA) is as effective, or superior, to standard cold preservation techniques used in upper limb transplantation today. We hypothesize that by using cellular and normothermic conditions during EVEP, we will see improved potential graft function compared to other protocols.

*Methods: Porcine forelimbs were perfused on an ex-vivo perfusion system with a buffered extracellular solution containing bovine serum albumin. A total of 18 limbs divided into 3 groups, each with n=6, underwent EVEP. Our two experimental protocols involved EVEP for 12 hours and stratified limbs into either a hypothermic (10°C) group with acellular perfusate, or a normothermic (38°C) group perfused with the addition of autologous packed red blood cells (pRBC). The third group had limbs stored at static cold conditions (4°C) for 6 hours, followed by EVEP at normothermia with pRBCs for 6 hours. Measured parameters include: arterial flow and resistance, compartment pressure, muscle response to electrical nerve stimulation, edema formation, histological analysis of tissues, and perfusate cytokine profiles.

*Results: Throughout EVEP, significant differences (p<0.05) between groups are evident in brachial artery flow, brachial artery resistance, compartment pressure, neuro-muscular stimulation, perfusate lactate concentrations, and in perfusate TNF-α, IL-8, and IL-6 concentrations. Weight gain as an indicator for edema also differs significantly between groups (Normothermic: 3.7%; hypothermic: 19.3%; cold storage: 13.5%; p=0.005, one-way ANOVA).

*Conclusions: Our results suggest that cellular normothermic conditions are superior to both cold storage and acellular hypothermic conditions when utilizing EVEP to preserve upper limb VCA grafts. With the potential of extremity transplantation critically limited by the 4-6 hours of preservation time currently offered by standard cold static storage, our results have shown that EVEP has the capacity to extend this time constraint in addition to potentially enhancing graft quality prior to transplantation.

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