Application Of Extracorporeal Membrane Oxygenation In The Maintenance Of Cardiac Death Donor Liver

Chronic liver disease(CLD)is considered a major cause of mortality worldwide,and particularly in China.The majority of CLD are initiated by Hepatitis B virus(HBV)and Hepatitis C virus(HCV)infection in China.A large number of CLD finally developed to end-stage liver disease,such as hepatic cirrhosis and liver cancer.Liver transplantation(LT)continues to be the standard therapy for patients with end-stage liver disease.Transplantation offers patients a marked improvement in their health and well-being.However,many more patients remain on waiting lists.The progressively increase of patients with end-stage liver disease is extending the waiting-list for liver transplantation,which,unfortunately,is not reached by a suitable increase in the number of donors.The shortage of donors for transplantation is a universal problem in worldwide,and the discrepancy between supply and demand is still increasing.Because of this ongoing problem,to meet the increasing demand for transplants,the transplant community has attempted to expand the donor organ sources in liver transplantation.Over the last few decades,methods to expand the donor organ pool have been developed.These include live donor liver transplantation,split-liver transplantation,donation after brain death(DBD)donor and donation after cardiac death(DCD)donor liver transplantation.DCD donor,formally known as non-heart-beating donors,the use of which has increased step by step in recent years over the world.Liver transplantation after DCD has increased steadily over the past decade.In countries with an active DCD program,DCD donors account for 5% to 35% of the total donation.Hence,the use of DCD has significantly augmented the donor pool for LT.Fortunately,the use of DCD organs has rapidly developed in China since the establishment of DCD standard by the Red Cross Society and Ministry of Health of China in 2010.DCD donors are generally considered ?extended-criteria donors.? Historically,the use of DCD grafts has been associated with higher risks of primary nonfunction(PNF),ischemic-type biliary lesion(ITBL),vascular thrombosis and so on,which are obviously due to the inevitable warm ischemia occurring during the declaration of death and organ retrieval process.The above phenomenon is consistent with our previous research.Standard liver preservation inevitably lead to pre-preservation injury,cold-preservation injury,re-warming injury,and reperfusion injury.Compared with the traditional cold preservation,recent improvement of organ preservation with perfusion machine might start a new era in graft availability,as these technological advances may help to minimize the morbid complications associated with conventional DCD grafts.A novel approach is the ?in-situ(vivo)? machine perfusion,named extracorporeal membrane oxygenation(ECMO)device,the first report of which assisting DCD donors after certification of cardiac death was in 2000.Our transplant center has been performing LT for nearly two decades.The use of DCD organs has also developed with multi-units help in recent years.There is very limited data on the performance of liver grafts that have been perfused in-situ with normothermic ECMO.In this clinical study,we aimed to explore the application of extracorporeal membrane oxygenation(ECMO)in the maintenance of the donor liver in cardiac death,and to develop a set of clinical strategies for coping with different situations of DCD donors.Methods Firstly,we discuss the current state of DCD in China.We define the DCD donor and describe the current protocols in management of the DCD patient with modified cardiopulmonary criteria.Secondly,we then discuss current techniques and methods in organ procurement and preservation.Determining when and how to support DCD donors with ECMO prior to organ retrieval.Finally,36 cases of DCD donor liver organs were protected by two ways.They were divided into two groups: ECMO protected DCD donor liver group(ECMO group)and routine treatment group(no ECMO group).The donor liver organs were evaluated and maintained for the stability of the donor environment,actively rectifying the acid,and protecting the liver when the liver function was abnormal before the donor liver organs were procured.In the course of donor maintenance treatment,ECMO group used ECMO technology to maintain donors.Without ECMO group,life support was removed in time,and the donor was stopped after 5 min.The pathology of donor liver,the incidence of primary liver nonfunction,the incidence of ischemic biliary tract disease,the incidence of acute rejection,and the liver function after transplantation were observed.Results There was a significant difference in the hepatocyte necrosis between ECMO group and non ECMO group before transplantation.There was no significant difference in hepatocyte fatty degeneration and hepatocyte degeneration.There were significant differences in the incidence of primary liver nonfunction and the incidence of ischemic biliary disease in the ECMO group and the non ECMO group(p=0.045,0.026).After liver transplantation,ALT,AST,TBIL,Alb and PT indicators,liver function indexes of ECMO group and ECMO group all decreased with time elapse,and ECMO group's index values were all lower than those of no ECMO group,and the differences were statistically significant.Conclusion New preservation strategies using in-situ/in-vivo(ECMO)technique exerts good effect on the maintenance of the donor liver in cardiac death,and DCD liver allografts could be more safely utilized in LT.In light of the continually growing disparity between organ supply and demand,DCD donation should regain more attention and have large potential in the future with the development and implementation of uniform guidelines.