Background: Ischemia and reperfusion injury remains a significant limiting factor for the success of vascularized composite allotransplantation. Compared to the cold storage of the procured organs, normothermic ex situ perfusion is a novel approach to prolong viability of the limb by maintaining physiologic cellular metabolism avoiding the deleterious effects of both hypoxia and cooling. This study aims to develop an ex-situ normothermic limb perfusion system to preserve the viability and function of amputated limbs for over 24 hours.

Methods: A total of 22 swine limbs were perfused. Limbs were perfused using an oxygenated colloid solution at 39[deg]C containing washed RBCs. The first 13 limbs were used to optimize the perfusion protocol. The subsequent 5 limbs (Group A) were perfused for 12 hours and the following 4 (Group B) as long as muscle contractility/peripheral perfusion was present. Electrolytes were kept within physiologic ranges by partial perfusate exchanges. Limb viability was assessed and compared in the 2 groups by muscle contractility, compartment pressure, tissue oxygen saturation, indocyanine green (ICG)-angiography and thermography.

Results: Perfused limbs were able to retain physiological parameters and function for 12 hours in group A and up to 44 hours (26-44) in group B. The final weight increase (0.54%±0.07 VS 16.25%±17.86) (p=0.15) and compartment pressure (16.23±7.10 VS 24.75±7.79) (p=0.175) were lower in group A compared to group B. The average muscle temperature was 33.54±1.5[deg]C in group A and 35.15±1.40[deg]C in group B (p=0.072). Final myoglobin and CK mean values were lower in group A compared with group B (875±291.4 ng/mL VS 1010.6±323.6 ng/mL and 53344±14850.34 U/L VS 71881±20475 ng/mL). Thermography and ICG-angiography showed minimal variations of peripheral limb perfusion overtime in both groups.

Conclusions: This protocol has shown the potential to significantly impact outcomes in limb transplantation. Our results suggest that limbs with shorter ex-situ perfusion retain better physiologic parameters and muscular contraction. However, the continuous optimization of the protocol allowed to maintain function and peripheral perfusion of perfused limbs for up to 44 hours.

CITATION INFORMATION: Dalla Pozza E, Duraes E, Madajka M, Frautschi R, Cho K, Dawlagala N, Fahradyan V, Shah H, Cakmakoglu C, Quintini C, Papay F, Rampazzo A, Bassiri Gharb B. Ex-Situ Extended Limb Preservation: A Protocol for Porcine Limb Perfusion. Am J Transplant. 2017;17 (suppl 3).

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