In an attempt to improve preservation of liver grafts, the concept of endischemic hypothermic oxygenated machine liver perfusion presents a simple, efficient and practical strategy to be used exclusively after organ transport at the site of organ transplantation.
Following standard back table preparation the provided disposable connects the liver with the perfusion machine (ECOPS system in human settings), which is a simple approach, since perfusion, done while recipient hepatectomy, proceeds exclusively over the portal vein. Importantly, during 1 to 2 hours of perfusion portal pressure needs to be constantly monitored, aiming for values below 3 mmHg. Furthermore, the perfusate recquires full saturation with oxygen, while perfusate and liver temperature is maintained between 4 and 10 ° C. After hepatectomy of the recipient the perfused graft is disconnected and transplanted.
The mechanisms of protection by hypothermic machine perfusion appear to be twofold.
First, oxygenation under hypothermic conditions protects from mitochondrial and nuclear injury by down regulation of mitochondrial activity before reperfusion. After 1 hour of perfusion, mitochondrial respiration appears significantly reduced in the presence of an oxygenated perfusate, suggesting that more than 1 h of HOPE treatment may not become necessary.
Second, cold perfusion itself, under low pressure conditions (≤ 3mmHg), cleans glycocalix and endothel, while preventing endothelial damage. Therefore, one h HOPE in the transplant center, during recipient hepatectomy is enough, indiciating a very good liver function after reperfusion (Ref.: Schlegel A, de Rougemont O, Graft R, Clavien PA, Dutkowski P. Protective mechanism of end-ischemic cold machine perfusion in DCD liver grafts, J Hepatol. 2012 Oct 11. No…..).