Normothermic ex situ liver perfusion might allow viability assessment of livers before transplantation. Perfusion characteristics were studied in 47 liver perfusions, of which 22 resulted in transplants. Hepatocellular damage was reflected in the perfusate transaminase concentrations, which correlated with posttransplant peak transaminase levels. Lactate clearance occurred within 3 hours in 46 of 47 perfusions, and glucose rose initially during perfusion in 44. Three livers required higher levels of bicarbonate support to maintain physiological pH, including one developing primary nonfunction. Bile production did not correlate with viability or cholangiopathy, but bile pH, measured in 16 of the 22 transplanted livers, identified three livers that developed cholangiopathy (peak pH < 7.4) from those that did not (pH > 7.5). In the 11 research livers where it could be studied, bile pH > 7.5 discriminated between the 6 livers exhibiting >50% circumferential stromal necrosis of septal bile ducts and 4 without necrosis; one liver with 25‐50% necrosis had a maximum pH 7.46. Liver viability during normothermic perfusion can be assessed using a combination of transaminase release, glucose metabolism, lactate clearance, and maintenance of acid‐base balance. Evaluation of bile pH may offer a valuable insight into bile duct integrity and risk of posttransplant ischemic cholangiopathy.

Organs recovered from donors after circulatory death (DCD) suffer warm ischemia before cold storage which may prejudice graft survival and result in a greater risk of complications after transplant. A period of normothermic regional perfusion (NRP) in the donor may reverse these effects and improve organ function. Twenty-one NRP retrievals from Maastricht category III DCD donors were performed at three UK centers. NRP was established postasystole via aortic and caval cannulation and maintained for 2 h. Blood gases and biochemistry were monitored to assess organ function. Sixty-three organs were recovered. Forty-nine patients were transplanted. The median time from asystole to NRP was 16 min (range 10-23 min). Thirty-two patients received a kidney transplant. The median cold ischemia time was 12 h 30 min (range 5 h 25 min-18 h 22 min). The median creatinine at 3 and 12 months was 107 mmol/L (range 72-222) and 121 mmol/L (range 63-157), respectively. Thirteen (40%) recipients had delayed graft function and four lost the grafts. Eleven patients received a liver transplant. The first week median peak ALT was 389 IU/L (range 58-3043). One patient had primary nonfunction. Two combined pancreaskidney transplants, one islet transplant and three double lung transplants were performed with primary function. NRP in DCD donation facilitates organ recovery and may improve short-term outcomes.

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BackgroundA program of normothermic ex situ liver perfusion (NESLiP) was developed to facilitate better assessment and use of marginal livers, while minimizing cold ischemia.MethodsDeclined marginal livers and those offered for research were evaluated. Normothermic ex situ liver perfusion was performed using an erythrocyte-based perfusate. Viability was assessed with reference to biochemical changes in the perfusate.ResultsTwelve livers (9 donation after circulatory death [DCD] and 3 from brain-dead donors), median Donor Risk Index 2.15, were subjected to NESLiP for a median 284 minutes (range, 122-530 minutes) after an initial cold storage period of 427 minutes (range, 222-877 minutes). The first 6 livers were perfused at high perfusate oxygen tensions, and the subsequent 6 at near-physiologic oxygen tensions. After transplantation, 5 of the first 6 recipients developed postreperfusion syndrome and 4 had sustained vasoplegia; 1 recipient experienced primary nonfunction in conjunction with a difficult explant. The subsequent 6 liver transplants, with livers perfused at lower oxygen tensions, reperfused uneventfully. Three DCD liver recipients developed cholangiopathy, and this was associated with an inability to produce an alkali bile during NESLiP.ConclusionsNormothermic ex situ liver perfusion enabled assessment and transplantation of 12 livers that may otherwise not have been used. Avoidance of hyperoxia during perfusion may prevent postreperfusion syndrome and vasoplegia, and monitoring biliary pH, rather than absolute bile production, may be important in determining the likelihood of posttransplant cholangiopathy. Normothermic ex situ liver perfusion has the potential to increase liver utilization, but more work is required to define factors predicting good outcomes.

Ischemia/reperfusion injury (IRI) that develops after liver implantation may prejudice long-term graft survival, but it remains poorly understood. Here we correlate the severity of IRIs that were determined by histological grading of time-zero biopsies sampled after graft revascularization with patient and graft outcomes. Time-zero biopsies of 476 liver transplants performed at our center between 2000 and 2010 were graded as follows: nil (10.5%), mild (58.8%), moderate (26.1%), and severe (4.6%). Severe IRI was associated with donor age, donation after circulatory death, prolonged cold ischemia time, and liver steatosis, but it was also associated with increased rates of primary nonfunction (9.1%) and retransplantation within 90 days (22.7%). Longer term outcomes in the severe IRI group were also poor, with 1-year graft and patient survival rates of only 55% and 68%, respectively (cf. 90% and 93% for the remainder). Severe IRI on the time-zero biopsy was, in a multivariate analysis, an independent determinant of 1-year graft survival and was a better predictor of 1-year graft loss than liver steatosis, early graft dysfunction syndrome, and high first-week alanine aminotransferase with a positive predictive value of 45%. Time-zero biopsies predict adverse clinical outcomes after liver transplantation, and severe IRI upon biopsy signals the likely need for early retransplantation. Liver Transpl 21:487-499, 2015. V C 2015 AASLD.

Correction made after online publication September 22, 2015: Author listing has been revised.Livers retrieved after circulatory death are associated with an increased incidence of primary nonfunction, early allograft dysfunction, and biliary strictures. The authors report a case of preimplant normothermic perfusion of a suboptimal liver from a 57-year-old donor after circulatory death who had been hospitalized for 9 days; predonation alanine transaminase level was 63 IU/L, and the period from withdrawal of life-supporting treatment to circulatory arrest was 150 minutes. After 5 hours of static cold storage, the liver was subject to normothermic machine perfusion with a plasma-free red cell-based perfusate. Perfusate lactate level fell from 7.2 to 0.3 mmol/L within 74 minutes of ex situ perfusion, at which point perfusate alanine transaminase level was 1152 IU/L and urea concentration was 9.4 mmol/L. After 132 minutes, normothermic perfusion was stopped and implantation begun. After transplantation, the patient made an uneventful recovery and was discharged on day 8; liver biochemistry was normal by day 19 and has remained normal thereafter. Donor common bile duct excised at implantation showed preservation of peribiliary glands, and cholangiography 6 months posttransplantation showed no evidence of cholangiopathy. Preimplant ex situ normothermic perfusion of the liver appears to be a promising way to evaluate a marginal liver before transplantation and may modify the response to ischemia.

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Cannulation and heparinization after circulatory arrest does not prevent successful normothermic regional perfusion. The technique permits evaluation of donor organs before implantation and may improve short-term outcomes.