Current Evidence and Future Perspectives to Implement Continuous and End-Ischemic Use of Normothermic and Oxygenated Hypothermic Machine Perfusion in Clinical Practice

Abstract

The use of high-risk renal grafts for transplantation requires the optimization of pretransplant assessment and preservation reconditioning strategies to decrease the organ discard rate and to improve short- and long-term clinical outcomes. Active oxygenation is increasingly recognized to play a central role in dynamic preservation strategies, independent of preservation temperature, to recondition mitochondria and to restore the cellular energy profile. The oxygen-related decrease in mitochondrial succinate accumulation ameliorates the harmful effects of ischemia-reperfusion injury. The differences between normothermic and hypothermic machine perfusion with regard to organ assessment, preservation, and reconditioning, as well as the logistic and economic implications, are factors to take into consideration for implementation at a local level. Therefore, these different techniques should be considered complementary to the perfusion strategy selected depending on functional intention and resource availability. This review provides an overview of the current clinical evidence of normothermic and oxygenated hypothermic machine perfusion, either as a continuous or end-ischemic preservation strategy, and future perspectives.

Organ storage in renal transplantation

“…Various machine perfusion protocols were initially quite popular in the 1970 s [14]. However, due to the lack of significant benefits that justified the increased cost and complexity, they fell out of favor [15 ▪ ]. Consequently, SCS became the standard organ preservation method.…”

“…HMP offers a theoretical advantage through the pulsatile flow it generates. This mechanical force aids in keeping the organ's microvasculature open and induces nitric oxide production and subsequent vasodilation due to the shear forces on the vascular endothelium [15 ▪ ]. The reduction in vasodilation and decreased intrarenal resistance promotes postreperfusion flow throughout the kidney [16].…”

“…The reduction in vasodilation and decreased intrarenal resistance promotes postreperfusion flow throughout the kidney [16]. Additionally, continuous circulation could potentially prevent the accumulation of debris, microthrombi, and toxic metabolites [15 ▪ ].…”