Non-heart Beating Research Articles

Ischemia-Reperfusion Injury in Cadaveric Nonheart Beating, Cadaveric Heart Beating and Live Donor Renal Transplants

Ischemia-reperfusion injury is gaining importance in transplantation as being responsible for allograft dysfunction. Ischemia occurs during kidney procurement, which is shortest in LDs, and prolonged in cadaveric HBDs and NHBDs. Renal transplants from 17 LDs, 15 HBDs and 19 NHBDs were assessed during reperfusion for biochemical markers of ischemia-reperfusion injury and assessed clinically. Central venous blood sampling was assayed for free radicals using electron spin resonance and tissue injury biomarkers, namely lactate dehydrogenase, fatty acid binding protein, alanine aminopeptidase, lactate and total antioxidants. The return to stable renal function was more rapid in LD renal transplants, while recovery continued from 3 months after hospital discharge in NHBD renal transplants. Injury markers, such as lactate dehydrogenase, fatty acid binding protein, alanine aminopeptidase and lactate, were raised at the time of reperfusion, especially in NHBD renal transplants. Free radical release measured by electron spin resonance showed 2 phase release, that is early (0 to 10-minute) and late (20 to 40-minute) release. In NHBD, HBD and LD renal transplants the index of free radical release in the early phase was 1.43, 1.36 and 1.20, and in the late phase it was 1.43, 1.38 and 0.97, respectively (each ANOVA p <0.05). NHBD renal transplants were accompanied by a greater release of free radicals at reperfusion (NHBD > HBD > LD), which was associated with an increase in tissue injury markers at reperfusion. This was reflected in a slower return to stable renal function in NHBD compared to HBD and LD renal transplants.

Wound Healing in the Biliary Tree of Liver Allografts

An increasing need for liver transplantation requires evaluation and triage of organs harvested from "extended criteria" donors. Although there is currently no widely accepted definition, most would agree that "extended criteria" includes organs donated by individuals that are old (>65 years), obese, infected with HBV or HCV, non-heart beating (NHBD), or had an unstable blood pressure before harvesting or the organ experienced a long cold ischemic time. These organs carry a statistical risk of dysfunction early after transplantation, but in the majority of recipients, hepatic parenchymal function recovers. Later, however, a small but significant percentage of extended criteria donors develop biliary strictures within several months after transplantation. The strictures occur primarily because of preservation injury that leads to "ischemic cholangitis" or deep wounding of the bile duct wall. Subsequent partial wound healing and wound contraction, but failed restitution of the biliary epithelial cell (BEC) lining, result in biliary tract strictures that cause progressive biliary fibrosis, increased morbidity, and decreased organ half-life. Better understanding of the pathophysiologic mechanisms that lead to biliary strictures in extended criteria donors provides an ideal proving ground for regenerative medicine; it also can provide insights into other diseases, such as extrahepatic biliary atresia and primary sclerosing cholangitis, that likely share certain pathogenic mechanisms. Possible points of therapeutic intervention include limiting cold and warm ischemic times, donor and/or donor organ treatment, ex vivo, to minimize the ischemic/preservation injury, maximize blood flow after transplantation, promote BEC wound healing, and limit myofibroblasts activation and proliferation in the bile duct wall. The pathobiology of biliary wound healing and therapeutic potential of interleukin-6 (IL-6) are highlighted.

Distinguishing between recurrent primary sclerosing cholangitis and chronic rejection

1. Recurrent primary sclerosing cholangitis (PSC) is extremely difficult, if not impossible, to distinguish from other causes of biliary strictures or sclerosing cholangitis in allografts using needle biopsy evaluation alone. Technical problems with biliary reconstruction, long cold ischemic times, non-heart beating donors, ABO blood group incompatibility, antibody-mediated rejection, and small-for-size syndrome in reduced-size or living donor livers can also cause similar manifestations in a peripheral core biopsy. 2. Some difficulties in distinguishing between sclerosing cholangitis and chronic rejection (CR) arise because: a) at risk populations are similar; b) both can cause "cholestatic" elevation of liver injury tests; and c) both can lead to intrahepatic cholestasis and small bile duct loss. 3. Etiopathogenesis and pathology of CR and sclerosing cholangitis have some overlapping features, but show distinct differences that result in significantly different and discriminating pathologic manifestations. 4. Clues in the clinical history, evaluation of serial biopsies, and histopathology can be used to distinguish with confidence between sclerosing cholangitis and CR. 5. Potential discriminating features include liver size and gross appearance, and histopathology findings in the arterial tree, hilar lymph nodes, large and small bile ducts, interface zone, lobular, and perivenular regions.

Successful Islet Transplantation From a Single Pancreas Harvested From a Young, Low-BMI, Non–Heart-Beating Cadaver

Background Young donors, donors with low body mass index (BMI), and non–heart-beating (NHB) donors are considered nonideal for islet transplantation. In this report, we successfully used a pancreas from a young, low-BMI, NHB donor for islet transplantation. Methods The donor was a 15-year-old adolescent boy whose cause of death was rupture of a primary brain tumor. According to Japanese regulations, his pancreas was procured after cardiac arrest. Warm ischemic time was 3 minutes and cold ischemic time was 300 minutes. The pancreas was digested by the automated method of Ricordi, followed by purification using continuous Euro-Ficoll gradients on a Cobe 2991 device. The recipient was a 35-year-old woman with unstable type 1 diabetes mellitus. Her pretransplant C-peptide level was null. She suffered frequent hypoglycemic unawareness. Her pretransplant M value, which is a good marker for glucose instability, was 125. Islet yield was 252,816 IEQ. There were no signs of contamination. Viability of islets assessed by FDA/PI staining was 83%. Stimulation index was 2.7. Results The patient received 5160 IEQ/kg of islets via the portal vein under local anesthesia. There were no transplant-related complications. Although she required minimal exogenous insulin, her C-peptide level increased to 0.7 ng/mL at postoperative day (POD) 14. Her M value at POD 15 to 19 decreased dramatically to 23.6, indicating good glycemic control. At 3 months posttransplant, episodes of hypoglycemia disappeared. Conclusions Although an additional transplant is mandatory to wean patients from insulin, this case shows the possibility of using marginal donors, such as a young, low-BMI, NHB donor, for pancreas islet transplantation.

The Start of an Islet Transplantation Program in Japan

In Japan, pancreas donation had become possible from cadaveric donor sources, both heart-beating or non–heart-beating (NHB). Pancreas allografts have been distributed in the organ allocation system of the Japan Organ Transplant Network. Meanwhile, islet transplantation has been categorized as a tissue transplantation; it is free from legal restraints. Thus, pancreata for islet isolation must be obtained from NHB donors. Herein we report the starting program and preliminary results of islet transplantation in Japan. Selection and listing criteria for transplantation include regional priority, ABO blood type, previous islet transplant status with insulin independence, and a longer waiting time. Five institutes in Japan (Fukushima, Chiba, Kyoto, Kobe, and Fukuoka) are prepared to start programs. A two-layer cold storage method using perfluorocarbons and UW solution is recommended for pancreas preservation. Islet isolation and purification procedures are performed according to institute-specific protocol. Immunosuppression is based on sirolimus/tacrolimus combined with basiliximab induction. Two or three consecutive infusions of >5000 IE/kg are planned for each recipient until achieving insulin independence. Twenty-seven isolations and 14 transplants were performed in eight non–insulin-dependent diabetes mellitus (IDDM) recipients. Almost all (26 of 27) were NHB donors. All recipients are free from hypoglycemic episode after transplantation. One of these recipients is insulin independent; the others are currently on minimal doses of exogenous insulin. The feasibility of islet transplantation using NHB donors was confirmed using a two-layer cold storage method and a steroid-free immunosuppressive protocol, with a high rate of graft function.

Possibility of Islet Transplantation from a Nonheartbeating Donor Pancreas Resuscitated by the Two-Layer Method

The shortage of cadaveric donors is a problem in islet transplantation, and recent improvements in this field have led to renewed interest in the use of nonheartbeating (NHB) donors. NHB donor pancreata that could provide a significant source for islet transplantation are associated with warm ischemic injury. We tested whether the two-layer method (TL) could improve islet yield and function from damaged pancreata after warm ischemia (WI). Lewis rats were divided into six groups. In groups 1 to 3, rats were subjected to 0, 30, and 45 minutes of WI, respectively. Islets were isolated immediately (subgroup a) or after 3-hour preservation with TL (subgroup b). Isolated islets were assessed in terms of islet yield and in vivo function. We also assessed the pancreatic tissue ATP concentration before isolation and distended pancreata morphologically after chemical digestion by H&E staining. Islet yield decreased significantly after 30 minutes of WI in group 2a, whereas TL preservation doubled this decreased yield in group 2b. Forty-five minutes of WI resulted in nearly no islet yield in both groups 3a and 3b. The success rates of transplantation in groups 1a, 1b, 2a, and 2b were 100%, 100%, 0%, and 75%, respectively. Increased tissue ATP levels and alleviation of morphological islet damage were observed in group 2b. These results demonstrated that pancreata damaged from 30-minute WI were restored by 3-hour TL preservation. TL may allow the selective use of NHB donors as an alternative source for islet transplantation.

UW Solution for Hypothermic Machine Perfusion of Warm Ischemic Kidneys

Donation of kidneys from non-heart beating donors (NHBD) is increasingly being used to expand the donor pool. Warm ischemic injury of these kidneys suffered at harvest results in DGF at transplantation. In this study, we used hypothermic continuous machine perfusion preservation to mitigate this injury using two available solutions. Dog kidneys (beagles) were exposed to 0, 60, or 75 min of in situ warm ischemia (37 degrees C), followed by 24 to 72 hr preservation by machine perfusion with Belzer MPS solution or the UW-solution (Viaspan). Auto-transplantation was performed with immediate contralateral nephrectomy. Survival and renal function (serum creatinine) were evaluated for up to 10 days posttransplant. Both solutions were equally effective for 72 hr machine perfusion preservation of dog kidneys giving 100% survival with only minor renal injury. Both solutions were also equally effective for preservation of kidneys exposed to 60 min of warm ischemia. However, only the UW solution gave reliable preservation (86% survival vs. 25% survival) in kidneys exposed to 75 min of warm ischemia and 24 hr machine perfusion. UW solution used with continuous hypothermic machine perfusion preservation can rescue canine kidneys from severe warm ischemic injury.

Non???Heart-Beating Donor Kidneys in The Netherlands: Allocation and Outcome of Transplantation

Since February 1, 2001, kidneys from both heart-beating (HB) and non-heart-beating (NHB) donors in The Netherlands have been indiscriminately allocated through the standard renal-allocation system. Renal function and allograft-survival rate for kidneys from NHB and HB donors were compared at 3 and 12 months. The outcomes of 276 renal transplants, 176 from HB donors and 100 from NHB III donors, allocated through the standard renal allocation system, Eurotransplant Kidney Allocation System, and performed between February 1, 2001 and March 1, 2002 were compared. Three months after transplantation, graft survival was 93.7% for HB kidneys and 85.0% for NHB kidneys (P<0.05). At 12 months, graft survival was 92.0% and 83.0%, respectively (P<0.03). Serum creatinine levels in the two groups were comparable at both 3 and 12 months. Multivariate analysis identified previous kidney transplantation (relative risk [RR] 3.33; P<0.005), donor creatinine (RR 1.01; P<0.005), and NHB (RR 2.38; P<0.05) as independent risk factors for transplant failure within 12 months. In multivariate analysis of NHB data, a warm ischemia time (WIT) of 30 minutes or longer (P<0.005; RR 6.16, 95% confidence interval 2.11-18.00) was associated with early graft failure. No difference in 12-month graft survival was seen between HB and NHB kidneys after excluding the kidneys that failed in the first 3 months. Early graft failure was significantly more likely in recipients of kidneys from NHB donors. A prolonged WIT was strongly associated with this failure. Standard allocation procedures do not have a negative effect on outcome, and there is no reason to allocate NHB kidneys differently from HB kidneys.

Successful outcome following transplantation of an injured liver from a nonheart beating donor

Nonheart beating donation (NHBD) of the liver is a relatively new potential source of grafts. Guidelines to indications and contraindications to donation from controlled nonheart beating donors are still being formulated. We report a successful case of transplantation of a liver from a controlled nonheart beating donor who sustained significant injuries following a road traffic accident. Emergency laparotomy with peri-hepatic packing was performed to control haemorrhage from lacerations in segments VI and VII. Forceful packing resulted in an area of focal ischaemia in segment VI. Trauma to the liver should not be considered an absolute contraindication to controlled NHBD.

Liver donation: surgical techniques

Efficient and technically sound graft procurement is an integral component of a liver transplant recipient's immediate and eventual outcome. Furthermore, the current era of organ scarcity increases the demand on the donor surgeon to extract the maximum potential from the existing pool, including the assessment and use of expanded criteria donors, nonheart beating donors, and the splitting of deceased donors to supply 2 recipients. The techniques described here represent the authors' combined experience with over 20 years and 3000 procurements. They are widely applicable to a broad patient population and can be routinely performed at donor hospitals without specialized equipment or staff.

The long-term outcome of tacrolimus in cadaveric kidney transplantation from non-heart beating donors

Tacrolimus (Tac), developed in 1990, has been applied as an immunosuppressive agent for liver, heart, and kidney transplantation and is known to have more powerful immunosuppressive effects than cyclosporine (CyA). To evaluate the efficacy of Tac in cadaveric kidney transplants from non-heart beating donors, we present the long-term outcome of patients receiving kidneys with ischemic damage, and compared it with that of CyA. Between July 1990 and December 2000, 55 patients with end-stage renal disease received kidneys from non-heart beating donors (Maastrichy category 3) and were treated with Tac and steroid immunosuppressive therapy. During the same period, we also performed 137 non-heart beating cadaveric renal transplants treated with CyA-based immunosuppressive therapy. The patient survival rate was 98% at 1 yr and 96% at 3-10 yr in the Tac group, and 97% at 1-3 yr, 93% at 5 yr and 85% at 10 yr in the CyA group. The graft survival rate was 91% at 1 yr, 80% at 3 yr, 63% at 5 yr and 34% at 10 yr in the Tac group, and 88% at 1 yr, 75% at 3 yr, 63% at 5 yr and 49% at 10 yr in the CyA group. There was no significant difference in either patient or graft survival rates between the two groups. Acute early rejection in the Tac group was less than that in the CyA group but acute tubular necrosis was the same in both groups. This indicates that Tac is available for cadaveric kidney transplants from non-heart beating donors. In conclusion, Tac is available as an immunosuppressive agent even for kidney transplants from non-heart beating donors.

Viabilidad de injerto de pacientes con trasplante renal de donante de cadáver en asistolia

Renal transplantation (RT) is currently the treatment of choice in end-stage renal disease. The Gregorio Marañón hospital performed 65 RT, 97.01 pmp, this year. To study the characteristics which RT patients from non-heart beating donors have in the immediate post-transplantation renogram. To know the evolution of the renal function, by renogram. Ten patients with NHBD graft out of 65 patients with RT were studied in the year 2003. The study is made up of 10 patients with RT from NHBD, with an average timing of warm ischemia of 35 min and average timing of cool ischemia 21 h. In the post-transplantation renal function study, 9 of then showed hemodilution and one an acute tubular necrosis (ATN) pattern. In most of the cases, the study was performed the day after the RT except for one that was performed on the 4th day (1.7 +/- 1 days). Renal perfusion was conserved in every case. The renal graft maintained this type of record until post-RT day 7 (6.67 +/- 0.57 days) and evolved towards ATN after day 10 (11.65 +/- 1.5 days) and normal range on day 55 +/- 51.1 post-transplantation. All patients supported the graft, with acceptable renal function, except one of then who was treated with transplantectomy due to a renal venous thrombosis. The renal function study showed "hemodilution" in the first post-transplantation in 90 % of the RT from NHBD. Evolution went from ATN to normality. The NHBD are adequate for transplantation, significantly shortening the waiting time for RN.

Potential suitability for transplantation of hearts from human non-heart beating donors: Data review from the Gift of Life Donor Program

Organ availability limits use of heart transplantation for treatment for end-stage heart disease. Hearts are currently obtained from donors declared brain dead (heart beating donors [HBD]). Although use of hearts from non-heart beating donors (NHBD) could reduce the shortage, they are considered unusable because of possible perimortem ischemic injury.

Liver transplantation from controlled non-heart beating donors in the United Kingdom: Paolo Muiesan, Raffaele Girlanda, Heather Taber, Matthew Bowles, Ragai R Mitry, Robin D Hughes, Anil Dhawan, Mohamed Rela, Nigel D Heaton, King's College Hospital, London Uk

Liver transplantation from controlled non-heart beating donors in the United Kingdom: Paolo Muiesan, Raffaele Girlanda, Heather Taber, Matthew Bowles, Ragai R Mitry, Robin D Hughes, Anil Dhawan, Mohamed Rela, Nigel D Heaton, King's College Hospital, London Uk

Does ex vivo vascular resistance reflect viability of non–heart-beating donor livers?

Aims The use of non–heart-beating (NHB) donor livers is limited by a higher risk for primary nonfunction and the absence of methods to measure this risk. This study was designed to determine whether ex vivo vascular resistance of livers correlates with the length of warm ischemia (WI), and, thus, with viability of NHB livers. Methods Porcine livers were recovered after 0, 45, or 90 minutes WI. Livers were flushed by gravity and cold stored for 3 hours. Thereafter, livers were perfused at 4°C. Portal vein (PV) and hepatic artery (HA) vascular resistance were calculated during liver flush-out and during 24 hours of machine perfusion. Results During flush-out, PV and HA vascular resistance were higher among livers with longer WI times; however, only in the PV did the results reach statistical significance. During machine perfusion, PV vascular resistance was low from the start and remained fairly constant. In contrast, HA vascular resistance was higher at the start but gradually diminished to reach a more constant value after 4–6 hours. No correlation was observed between HA or PV vascular resistance and WI during machine perfusion. Conclusions The vascular resistance during ex vivo machine perfusion of NHB livers does not correlate with the extent of WI damage and, therefore, cannot predict organ viability.

GRAFT FUNCTION AFTER KIDNEY TRANSPLANTATION FROM NON-HEARTBEATING DONORS ACCORDING TO MAASTRICHT CATEGORY

Donor shortages have led to some groups using alternative sources such as non-heartbeating donors (NHBDs). Kidneys from NHBDs suffer from warm ischemia at cardiac arrest which is reflected by acute tubular necrosis of the allograft, resulting in a period of delayed graft function. NHBDs are categorized by the circumstances surrounding the agonal events of death which reflect differences in the likelihood of ischemic injury to the kidney. In this study we determined the impact of ischemic injury on the renal function of kidneys procured from different categories of NHBDs. From 1998 to 2003, 144 kidneys were procured from 72 NHBDs resulting in 93 transplants characterized into Maastricht categories II, III and IV NHBD renal transplants. Renal function after transplant was evaluated from the last dialysis until discharge from hospital, and then at 3 monthly intervals thereafter. Primary warm ischemic time is more prolonged in the uncontrolled donor (category II) than controlled donor (category III greater than IV). Delayed graft function occurs more frequently (Maastricht category II 83.8%, III 67.4% and IV 0%, ANOVA p <0.05) and the return to normal function is more prolonged in uncontrolled donors. This is illustrated by the greater incidence of acute tubular necrosis (Maastricht category II 81.1%, III 65.2% and IV 50.0%, ANOVA p = nonsignificant) in the kidney allograft. There was no difference in year 1 allograft survival (Maastricht category II 83.9%, III 92.5% and IV 100%, ANOVA p = nonsignificant). Early graft function is poorest in kidneys derived from Maastricht category II donors and best in category IV with III in-between. However, after 3 months the function of kidneys from all donors is the same.

A report on the activity and clinical outcomes of renal non‐heart beating donor transplantation in the United Kingdom

The use of kidneys from non-heart beating donors (NHBDs) presents a paradox; whilst they provide more organs for transplantation, there is an increased risk of poor graft outcome, particularly in the short term. This study has highlighted the difference in early graft function and late graft survival between NHBD kidneys with short (controlled) and long (uncontrolled) warm ischaemic times. Whilst it would seem that it is preferable to use controlled donors only, their numbers are small. By employing a rational approach to the use of each of these types of kidney, such as structured viability assessment and risk analysis, it may be that the results of uncontrolled NHBD can be improved.

A novel extracorporeal kidney perfusion system: a concept model

The number of patients awaiting kidney transplantation has more than doubled in the past decade while the number of available donor organs has seen only a modest increase, leading to a critical shortage of organs. In response to this extreme shortage, the criteria for accepting organs have been modified to include marginal donors such as non-heart beating donors (NHBD). In these kidneys, determining viability is important for success of transplantation. Therefore, a study was undertaken to develop a system that would allow the extracorporeal assessment of function and compatibility of the donor organ before the patient is exposed to the risks associated with surgery. Following bilateral nephrectomy, the kidneys of 10 pigs (approximately 30 kg) were connected to a commercially available hypothermic pulsatile kidney perfusion apparatus. This system was modified to allow for normothermic pulsatile renal perfusion using the potential recipient's blood, via vascular access. These kidneys were perfused with the animal's blood for a minimum of two hours while various parameters were monitored. Perfusion pressures were kept between 60 and 90 mmHg, which correlated to flows between 70 and 150 mL/min. A decrease in perfusion pressure with a concomitant rise in flow over the two-hour period served as a good predictor of a viable and compatible graft. The modified kidney preservation system allows the normothermic, pulsatile extracorporeal perfusion of donor kidneys with the ability to monitor resistance to flow and urine production. This model also allows observation of the kidney for signs of hyperacute rejection. Further research needs to be conducted in order to determine if the system represents a methodology to increase the pool of available donor organs.

NON-HEART-BEATING DONOR KIDNEYS IN THE NETHERLANDS, ALLOCATION AND OUTCOME OF TRANSPLANTATION

O398* Aim: Kidneys from non-heart-beating (NHB) donors have successfully been transplanted in the Netherlands since the early eighties. Currently one third of all renal transplantations in the Netherlands are with kidneys from NHB donors, a higher rate than anywhere else in the world. In the Netherlands we have a national waiting list managed by the Dutch Transplant Foundation (NTS). Kidneys from both heart beating (HB) and NHB donors are indiscriminately allocated through the regular renal allocation system. Hence all Dutch renal transplant candidates on the waiting list are potential NHB kidney recipients. Methods: In this abstract we report the 3 and 12 months outcome data of all renal allograft transplanted in the Netherlands between 1-2-2001 and 1-03-2002. Outcome data for kidneys from NHB donors were compared to those of HB donors. Recipient and donor factors were analyzed and the following outcome measures assessed: renal function and allograft survival rate, both at three and twelve months. Risk factors for graft failure were evaluated in a Cox proportional hazard model. Results: In the study period 332 adult patients received a kidney, 221 from a HB donor and 111 from a NHB donor. 17 (7.7%) HB and 16 (14.5%) NHB kidneys failed within 3 months (p=0.05). The 12 month graft survival rate was 90% and 82.7%, for HB and NHB respectively (p=0.06). Both at 3 and 12 months after transplantation serum creatinin was comparable in the two groups (152 mmol and 144 mmol) and (158mmol and 145 mmol) for HB and NHB respectively (p=0.4). Multivariate analysis identified a previous kidney transplantation (RR 2.9 (p=0.01)), a donor creatinin of > 150mmol (RR 3.8 (p=0.003)), and a prolonged warm ischaemic time (≥30 minutes) (RR 6.7 (p<0.001)), as independent risk factors for transplant failure within 12 months. No difference in 12 months graft survival was seen between HB and NHB kidneys after excluding the kidneys which failed in the first three months after transplantation. Conclusion: Kidneys from NHB donors are an important addition to the organ pool. The incidence of graft failure within three months is significantly higher in recipients of kidneys from NHB donors. After correction for early failure graft survival in HB and NHB kidneys is comparable at 12 months Twelve months after transplantations there is no difference in renal function between the study groups.

DOES EX VIVO VASCULAR RESISTANCE REFLECT VIABILITY OF NON-HEART-BEATING LIVERS?

P115 Aims: Non-heart-beating (NHB) donor livers could decrease mortality on liver transplant (LTx) waiting lists, but their use is limited by a high risk for primary-non-function (PNF) and the absence of methods to measure this risk. For NHB kidneys, vascular resistance (Vasc Res) during ex vivo Machine Perfusion (MP) is a simple and reliable parameter of postTx viability. The purpose of this study was to evaluate ex vivo methods capable of predicting organ viability in vivo. The study was designed to determine whether ex vivo Vasc Res of livers exposed to various periods of Warm Ischemia (WI) correlates with viability postTx. Methods: Porcine livers were recovered after 0’, 45’, and 90’ WI (5 in each group). These WI times were selected based upon prior in vivo LTx validation-experiments correlating 0’WI with normal viability and no PNF, 45’WI with altered viability and high PNF, and 90’WI with complete loss of viability, universal PNF and recipient death. Livers were flushed by gravity via the Portal Vein (PV) and the Hepatic Artery (HA) with 10L 4°C Histidine-Thryptophane-Ketoglutarate (HTK), and cold stored for 3 hrs. Thereafter, livers were perfused with 4°C modified-Belzer solution, using a specifically designed liver MP prototype (Organ Recovery Systems) including an unlimited flow - pressure controlled (30mmHG) and a flow limited (600ml/min) pressure controlled (7mmHg) system for HA and PV, respectively. Vasc Res were calculated in vivo after WI during liver flush-out and ex vivo continuously thereafter during 24 hrs of MP. Markers of hepatocyte damage (AST/LDH) were analysed in the liver effluent during flush-out and in the MP perfusate. Results: During flush-out, PV Vasc Res was lower than HA Vasc Res in all WI groups (p<0.0001). PV Vasc Res after 90’ WI was higher than after 0’ and 45’WI (p=0.003). A similar trend was seen for HA Vasc Res (higherVasc Res with longer WI) but this did not reach significance (p=0.24). During MP, PV Vasc Res was low from the start (0-0.05 mmHg.min/ml) and remained fairly constant during the 24 hr observation period whereas HA Vasc Res was higher at the start but gradually diminished to reach a more constant value after 4-to-6 hours (0.25 – 0.35 mmHg.min/ml). This evolution was similar in all WI groups and no correlation was observed between HA/PV Vasc Res and WI. AST and LDH in the liver effluent at flush-out and in the MP perfusate correlated with WI (p=0.001). Conclusions: Contrary to the kidney, Vasc Res during ex vivo MP of NHB livers does not correlate with the extent of WI damage and does not predict organ viability/function after Tx in the model studied. Whether modifying the experimental design could unmask this correlation or whether this absence of correlation is inherent in the unique vascular physiology of the liver (double vascular circuit/low resistance sinusoidal network) is under evaluation. Other ex vivo parameters, among them enzyme release, correlate with WI damage and viability postTx.