Liver transplantation from controlled non-heart-beating donors

The evolution of the liver transplant candidate

The first successful human liver transplant (LT) was done over 60 years ago; since the early pioneering days, this procedure has become a routine treatment with excellent outcomes for the great majority of recipients. Over the last six decades, indications have evolved. Use of LT for hepatic malignancy is becoming less common as factors that define a successful outcome are being increasingly defined, and alternative therapeutic options become available. Both Hepatitis B and C virus associated liver disease are becoming less common indications as medical treatments become more effective in preventing end-stage disease. Currently, the most common indications are alcohol-related liver disease and metabolic associated liver disease. The developing (and controversial) indications include acute on chronic liver failure, alcoholic hepatitis and some rarer malignancies such as non-resectable colorectal cancer liver metastases, neuroendocrine tumours and cholangiocarcinoma. Candidates are becoming older and with greater comorbidities, A relative shortage of donor organs remains the greatest cause for reducing access to LT; therefore, various countries have developed transparent approaches to allocation of this life saving and life enhancing resource. Reliance on prognostic models has gone some way to improve transparency and increase equity of access but these approaches have their limitations.

Deceased donor kidney procurement: Systematic review of the surgical technique

INTRODUCTION

Kidney procurement procedure must be carried out following a standardized technique in order to optimize kidney grafts for their subsequent implantation.

OBJECTIVES

Review of the available literature on kidney procurement procedure.

MATERIAL AND METHODS

Narrative review of the available evidence on deceased donor kidney procurement technique after a search of relevant manuscripts indexed in PubMed, EMBASE and Scielo written in English and Spanish.

RESULTS

Deceased donor kidney procurement can be divided into two groups, donation after brain death (DBD) and donation after circulatory death (DCD). Kidney procurement in DBD frequently includes other chest and/or abdominal organs, requiring multidisciplinary surgical coordination. During the harvesting procedure, the renal vascular pedicle must remain intact for subsequent implantation and reduced ischemia time.

CONCLUSIONS

Adequate execution and perfect knowledge of the technique for surgical removal and anatomy reduces the rate of graft losses associated to inadequate harvesting techniques.

Risk factors and management of hepatic artery stenosis post liver transplantation

BACKGROUND

Hepatic Artery Stenosis (HAS) after liver transplantation (LT), if untreated, can lead to hepatic artery thrombosis (HAT) that carries significant morbidity.

AIMS

To identify risk factors associated with HAS and determine if endovascular therapy (EVT) reduces the occurrence of HAT.

METHODS

This is a retrospective cohort study of adult LT patients between 2013 and 2018. The primary outcome was development of HAT, and secondary outcomes included graft failure and mortality. Logistic regression was used to ascertain the odds ratio of developing HAS. Outcomes between intervention types were compared with Fisher's-exact test.

RESULTS

The odds of HAS doubled in DCD-donor recipients (OR=2.27; P = 0.04) and transplants requiring vascular reconstruction for donor arterial variation (OR=2.19, P = 0.046). Of the 63 identified HAS patients, 44 underwent EVT, 7 with angioplasty alone, 37 combined with stenting. HAT was not significantly different in those who underwent angioplasty with or without stenting than conservative treatment (P = 0.71). However, compared to patients without HAS, patients with HAS had higher odds of biliary stricture and decreased graft and overall patient survival (log-rank P < 0.001 & P = 0.019, respectively).

CONCLUSION

HAS is significantly higher in DCD-graft recipients. EVT was not associated with reduction in HAT progression. HAS has poor graft and overall survival.

Impact of the donor hepatectomy time on short-term outcomes in liver transplantation using donation after circulatory death: A review of the US national registry

BACKGROUND

During the donor hepatectomy time (dHT), defined as the time from the start of cold perfusion to the end of the hepatectomy, liver grafts have a suboptimal temperature. The aim of this study was to analyze the impact of prolonged dHT on outcomes in donation after circulatory death (DCD) liver transplantation (LT).

METHODS

Using the US national registry data between 2012 and 2020, DCD LT patients were separated into 2 groups based on their dHT: standard dHT (<42 min) and prolonged dHT (≥42 min).

RESULTS

There were 3810 DCD LTs during the study period. Median dHT was 32 min (IQR 25-41 min). Kaplan- Meier graft survival curves demonstrated inferior outcomes in the prolonged dHT group at 1-year after DCD LT compared to those in the standard dHT group (85.3% vs 89.9%; p < 0.01). Multivariate Cox proportional hazards models for 1-year graft survival identified that prolonged dHT [hazard ratio (HR) 1.46, 95% confidence interval (CI) 1.19 - 1.79], recipient age ≥ 64 years (HR 1.40, 95% CI 1.14 - 1.72), and MELD score ≥ 24 (HR 1.43, 95% CI 1.16 - 1.76) were significant predictors of 1-year graft loss. Spline analysis shows that the dHT effects on the risk for 1-year graft loss with an increase in the slope after median dHT of 32 min.

CONCLUSION

Prolonged dHTs significantly reduced graft and patient survival after DCD LT. Because dHT is a modifiable factor, donor surgeons should take on cases with caution by setting the dHT target of < 32 min. This article is protected by copyright. All rights reserved.

Primary Nonfunction of the Liver Allograft

Severe allograft dysfunction, as opposed to the expected immediate function, following liver transplantation is a major complication, and the clinical manifestations of such that lead to either immediate retransplant or death are the catastrophic end of the spectrum. Primary nonfunction (PNF) has declined in incidence over the years, yet the impact on patient and healthcare teams, and the burden on the organ pool in case of the need for retransplant should not be underestimated. There is no universal test to define the diagnosis of PNF, and current criteria are based on various biochemical parameters surrogate of liver function; moreover, a disparity remains within different healthcare systems on selecting candidates eligible for urgent retransplantation. The impact on PNF from traditionally accepted risk factors has changed somewhat, mainly driven by the rising demand for organs, combined with the concerted approach by clinicians on the in-depth understanding of PNF, optimal graft recipient selection, mitigation of the clinical environment in which a marginal graft is reperfused, and postoperative management. Regardless of the mode, available data suggest machine perfusion strategies help reduce the incidence further but do not completely avert the risk of PNF. The mainstay of management relies on identifying severe allograft dysfunction at a very early stage and aggressive management, while excluding other identifiable causes that mimic severe organ dysfunction. This approach may help salvage some grafts by preventing total graft failure and also maintaining a patient in an optimal physiological state if retransplantation is considered the ultimate patient salvage strategy.

The role of extracorporeal membrane oxygenation in adult liver transplant patients: A qualitative systematic review of literature

BACKGROUND

A paucity of evidence exists regarding risks and benefits of extracorporeal membrane oxygenation (ECMO) in adult liver transplantation.

METHODS

This was a systematic review conducted from January 1, 2000 to April 24, 2020 of adult liver transplant recipients (pre- or post-transplant) and donors who underwent Veno-arterial or Veno-venous ECMO cannulation. Death was the primary outcome, with graft function and complications as secondary outcomes.

RESULTS

Forty-one articles were identified that fit criteria. A total of 183 donors were placed on ECMO, with recipient complication profiles and mortality that mirrored rates from standard criteria donors. Sixty-one recipients were placed on ECMO intraoperatively or postoperatively. Most patients experienced at least one complication with infections as the most common cause and minimal complications specifically related to ECMO use. Multisystem organ failure (MSOF) and infections were more common among liver recipients who died compared to those who survived. Overall mortality at 90 days was 45.9%. Causes of death were most commonly MSOF and infections.

CONCLUSIONS

ECMO use in adult liver transplantation is a useful adjunct. Recipient morbidity and mortality from donors placed on ECMO parallel that of recipients from standard criteria donors, and morbidity and mortality of recipients placed on ECMO are similar to other ECMO populations.

Ex vivo machine perfusion: current applications and future directions in liver transplantation

BACKGROUND

Liver transplantation is the only curative treatment option for end-stage liver disease; however, its use remains limited due to a shortage of suitable organs. In recent years, ex vivo liver machine perfusion has been introduced to liver transplantation, as a means to expand the donor organ pool.

PURPOSE

To present a systematic review of prospective clinical studies on ex vivo liver machine perfusion, in order to assess current applications and highlight future directions.

METHODS

A systematic literature search of both PubMed and ISI web of science databases as well as the ClinicalTrials.gov registry was performed.

RESULTS

Twenty-one articles on prospective clinical trials on ex vivo liver machine perfusion were identified. Out of these, eight reported on hypothermic, eleven on normothermic, and two on sequential perfusion. These trials have demonstrated the safety and feasibility of ex vivo liver machine perfusion in both standard and expanded criteria donors. Currently, there are twelve studies enrolled in the clinicaltrials.gov  registry, and these focus on use of ex vivo perfusion in extended criteria donors and declined organs.

CONCLUSION

Ex vivo liver machine perfusion seems to be a suitable strategy to expand the donor pool for liver transplantation and holds promise as a platform for reconditioning diseased organs.

A Simple and Useful Predictive Assay for Evaluating the Quality of Isolated Hepatocytes for Hepatocyte Transplantation

No optimal assay for assessing isolated hepatocytes before hepatocyte transplantation (HTx) has been established, therefore reliable and rapid assays are warranted. Isolated rat hepatocytes were dipped in a water bath (necrosis model), and were also cultured with Okadaic acid (apoptosis model) or vehicle, followed by cellular assessment including trypan blue exclusion (TBE) viability, ADP /ATP ratio, plating efficiency (PE), DNA quantity and ammonia elimination. Hepatocytes were transplanted into the liver of analbuminemic rats, subsequently engraftment was assessed by serum albumin and the histology of transplanted grafts. In the necrosis model, the ADP/ATP ratio was strongly and negatively correlated with the TBE (R² = 0.559, P < 0.001). In the apoptosis model, the ADP/ATP ratio assay, PE, DNA quantification and an ammonia elimination test clearly distinguished the groups (P < 0.001, respectively). The ADP/ATP ratio, PE and DNA quantity were well-correlated and the ammonia elimination was slightly correlated with the transplant outcome. TBE could not distinguish the groups and was not correlated with the outcome. The ADP/ATP ratio assay predicted the transplant outcome. PE and DNA quantification may improve the accuracy of the retrospective (evaluations require several days) quality assessment of hepatocytes. The ADP/ATP ratio assay, alone or with a short-term metabolic assay could improve the efficiency of HTx.

Study protocol for a multicenter randomized controlled trial to compare the efficacy of end-ischemic dual hypothermic oxygenated machine perfusion with static cold storage in preventing non-anastomotic biliary strictures after transplantation of liver grafts donated after circulatory death: DHOPE-DCD trial

BACKGROUND

The major concern in liver transplantation of grafts from donation after circulatory death (DCD) donors remains the high incidence of non-anastomotic biliary strictures (NAS). Machine perfusion has been proposed as an alternative strategy for organ preservation which reduces ischemia-reperfusion injury (IRI). Experimental studies have shown that dual hypothermic oxygenated machine perfusion (DHOPE) is associated with less IRI, improved hepatocellular function, and better preserved mitochondrial and endothelial function compared to conventional static cold storage (SCS). Moreover, DHOPE was safely applied with promising results in a recently performed phase-1 study. The aim of the current study is to determine the efficacy of DHOPE in reducing the incidence of NAS after DCD liver transplantation.

METHODS

This is an international multicenter randomized controlled trial. Adult patients (≥18 yrs. old) undergoing transplantation of a DCD donor liver (Maastricht category III) will be randomized between the intervention and control group. In the intervention group, livers will be subjected to two hours of end-ischemic DHOPE after SCS and before implantation. In the control group, livers will be subjected to care as usual with conventional SCS only. Primary outcome is the incidence of symptomatic NAS diagnosed by a blinded adjudication committee. In all patients, magnetic resonance cholangiography will be obtained at six months after transplantation.

DISCUSSION

DHOPE is associated with reduced IRI of the bile ducts. Whether reduced IRI of the bile ducts leads to lower incidence of NAS after DCD liver transplantation can only be examined in a randomized controlled trial.

TRIAL REGISTRATION

The trial was registered in Clinicaltrials.gov in September 2015 with the identifier NCT02584283 .

Onset of Donor Warm Ischemia Time in Donation After Circulatory Death Liver Transplantation: Hypotension or Hypoxia?

The aim of this study was to investigate the impact of hypoxia and hypotension during the agonal phase of donor warm ischemia time (DWIT) on hepatic ischemia/reperfusion injury (IRI) and complications in donation after circulatory death (DCD) liver transplantation. A retrospective single-center study of 93 DCD liver transplants (Maastricht type III) was performed. DWIT was divided into 2 periods: the agonal phase (from withdrawal of treatment [WoT] until circulatory arrest) and the asystolic phase (circulatory arrest until cold perfusion). A drop to <80% in peripheral oxygenation (SpO₂ ) was considered as hypoxia in the agonal phase (SpO₂ -agonal) and a drop to <50 mm Hg as hypotension in the agonal phase (SBP-agonal). Peak postoperative aspartate transaminase level >3000 U/L was considered as severe hepatic IRI. SpO₂ dropped within 2 minutes after WoT <80%, whereas the systolic blood pressure dropped to <50 mm Hg after 9 minutes, resulting in a longer SpO₂ -agonal (13 minutes) than SBP-agonal (6 minutes). In multiple logistic regression analysis, only duration of SpO₂ -agonal was associated with severe hepatic IRI (P = 0.006) and not SBP-agonal (P = 0.32). Also, recipients with long SpO₂ -agonal (>13 minutes) had more complications with a higher Comprehensive Complication Index during hospital admission (43.0 versus 32.0; P = 0.002) and 90-day graft loss (26% versus 6%; P = 0.01), compared with recipients with a short SpO₂ -agonal (≤13 minutes). Furthermore, Cox proportional hazard modeling identified a long SpO₂ -agonal as a risk factor for longterm graft loss (hazard ratio, 3.30; 95% confidence interval, 1.15-9.48; P = 0.03). In conclusion, the onset of hypoxia during the agonal phase is related to the severity of hepatic IRI and postoperative complications. Therefore, SpO₂ <80% should be considered as the start of functional DWIT in DCD liver transplantation.

Perspective review on solid-organ transplant: needs in point-of-care optical biomarkers

Solid-organ transplant is one of the most complex areas of modern medicine involving surgery. There are challenging opportunities in solid-organ transplant, specifically regarding the deficiencies in pathology workflow or gaps in pathology support, which may await alleviations or even de novo solutions, by means of point-of-care, or point-of-procedure optical biomarkers. Focusing the discussions of pathology workflow on donor liver assessment, we analyze the undermet need for intraoperative, real-time, and nondestructive assessment of the donor injuries (such as fibrosis, steatosis, and necrosis) that are the most significant predictors of post-transplant viability. We also identify an unmet need for real-time and nondestructive characterization of ischemia or irreversible injuries to the donor liver, earlier than appearing on morphological histology examined with light microscopy. Point-of-procedure laparoscopic optical biomarkers of liver injuries and tissue ischemia may also facilitate post-transplant management that is currently difficult for or devoid of pathological consultation due to lack of tools. The potential and pitfalls of point-of-procedure optical biomarkers for liver assessment are exemplified in breadth for steatosis. The more general and overarching challenges of point-of-procedure optical biomarkers for liver transplant pathology, including the shielding effect of the liver capsule that was quantitated only recently, are projected. The technological and presentational benchmarks that a candidate technology of point-of-procedure optical biomarkers for transplant pathology must demonstrate to motivate clinical translation are also foreseen.

The 24-hour normothermic machine perfusion of discarded human liver grafts

Donor organ shortage necessitates use of less than optimal donor allografts for transplantation. The current cold storage preservation technique fails to preserve marginal donor grafts sufficiently. Evidence from large animal experiments suggests superiority of normothermic machine preservation (NMP) of liver allografts. In this study, we analyze discarded human liver grafts that underwent NMP for the extended period of 24 hours. Thirteen human liver grafts which had been discarded for transplantation were entered into this study. Perfusion was performed with an automated device using an oxygenated, sanguineous perfusion solution at normothermia. Automated control was incorporated for temperature-, flow-, and pressure-regulation as well as oxygenation. All livers were perfused for 24 hours; parameters of biochemical and synthetic liver function as well as histological parameters of liver damage were analyzed. Livers were stratified for expected viability according to the donor's medical history, procurement data, and their macroscopic appearance. Normothermic perfusion preservation of human livers for 24 hours was shown to be technically feasible. Human liver grafts, all of which had been discarded for transplantation, showed levels suggesting organ viability with respect to metabolic and synthetic liver function (to varying degrees). There was positive correlation between instantly available perfusion parameters and generally accepted predictors of posttransplant graft survival. In conclusion, NMP is feasible reliably for periods of at least 24 hours, even in highly suboptimal donor organs. Potential benefits include not only viability testing (as suggested in recent clinical implementations), but also removal of the time constraints associated with the utilization of high-risk livers, and recovery of ischemic and other preretrieval injuries (possibly by enabling therapeutic strategies during NMP). Liver Transplantation 23 207-220 2017 AASLD.

Outcome of pancreas transplantation from donation after circulatory death compared to donation after brain death

INTRODUCTION

To overcome the gap of organ shortage grafts from donation after circulatory death (DCD) can be used. This review evaluates the outcomes after DCD pancreas donation compared to donation after brain death (DBD).

MATERIALS AND METHODS

A literature search was performed using Medline, Embase, and PubMed databases. All comparative cohort studies reporting the outcome after DCD and DBD pancreas transplantation were included. All data were assessed according to the Meta-analysis of Observational Studies in Epidemiology (MOOSE) guidelines. To evaluate the event rates, pooled odds ratios (ORs) as well as the 95% confidence intervals (CI) were calculated. Since the number of studies is small we used the random-effects model only to overcome heterogeneity.

RESULTS

There is no difference in 1-year pancreas graft survival (OR 1.092, CI 95% 0.649-1.837, P = 0.741) or patient survival (OR 0.699, CI 95% 0.246-1.985, P = 0.502). Simultaneous pancreas-kidney (SPK) transplantation showed significantly higher graft survival rates compared to pancreas transplantation alone (87.2% vs. 76.6%, P < 0.001 in DBD and 86.5% vs. 74.9%, P < 0.001 in DCD). DCD SPK grafts show a higher delayed kidney graft function rate compared to DBD SPK-grafts (OR 0.209, CI 95% 0.104-0.421, P < 0.001). There is significantly less pancreas graft thrombosis after DBD-donation (OR 0.567, CI 95% 0.340-0.946, P = 0.030). We found no difference in the HbA1c level at 1-year follow-up with a median of 5.4% in both groups and a mean of 5.63% (DCD) vs 5.43% (DBD).

DISCUSSION

DCD pancreas transplantation has comparable patient and 1-year graft survival rates and should be considered a safe alternative for DBD pancreas transplantation.

Development of the University of Wisconsin Donation after Cardiac Death Evaluation Tool

Background

Donation after cardiac death is a method by which severely neurologically injured patients not fulfilling brain-death criteria can donate organs.

Objective

To develop an evaluation tool that can be used to predict if a patient is a suitable candidate for donation after cardiac death.

Methods

The University of Wisconsin Donation After Cardiac Death Evaluation Tool assigns numeric values to observable clinical parameters to yield an overall predictive score of suitability for donation after cardiac death. This evaluation tool is typically utilized in a critical care unit to evaluate patients with a severe neurological injury, who do not meet brain-death criteria, and for whom the physician and family have chosen to terminally withdraw life support. Each patient is disconnected from a ventilator and observed for up to 10 minutes. Observations are then scored to yield a prediction of suitability for donation after cardiac death.

Results

Using the University of Wisconsin Donation After Cardiac Death Evaluation Tool, we were able to predict suitability for donation after cardiac death 83.7% of the time, within a 60-minute period and 74.4% of the time within a 120-minute period. The actual results using the tool were higher when clinical observations were included in the donation after cardiac death evaluation—an overall accuracy of 88.4%.

Development of a Successful Non—Heart-Beating Organ Donation Program

To help alleviate the organ shortage, transplant centers are using organs from expanded-criteria donors, who were considered unsuitable just a few years ago, such as Non—Heart-beating donors. In 1998, we made a concerted effort to increase the number of Non—Heart-beating donors recovered by our organ procurement organization. In this paper, we discuss the steps in establishing this program, including transplant center support, estimating the number of potential Non—Heart-beating donors, organ procurement support, protocol development, hospital development, education, putting the protocol into practice, follow-up, and effect of the program on organ procurement. With the establishment of this program, the number of Non—Heart-beating donors increased from 2% to 5% per year to over 10% for the past 2 years. From these donors, 61 of 82 recovered kidneys were transplanted into 58 patients, and 18 of 20 recovered livers were transplanted. A Non—Heart-beating donor program can significantly add to the number of organ transplants and successful transplantations.

Donation after Cardiac Death: Two Case Studies

Few transplant centers consider using lungs from cardiac death donors because of warm ischemic damage. In certain scenarios, the recovery and transplantation of lungs from cardiac death donors are appropriate. A young person with a severe neurologic and spinal cord injury, who is not brain dead and who is otherwise healthy, should be considered as a cardiac death donor. A protocol should be established with local lung transplant surgeons to facilitate the successful procurement of lungs from cardiac death donors. In addition, when patients present to hospital emergency rooms with nonsurvivable injuries either in cardiac arrest or with extremely labile vital signs, uncontrolled donation after cardiac death can be considered. It is important to obtain informed consent from the family and to suspend any previous do-not-resuscitate orders before initiating resuscitative efforts. If an organ procurement coordinator and team are within close proximity to the hospital, consideration should be given to uncontrolled donation after cardiac death.

Donations After Circulatory Death in Liver Transplant

The supply of liver grafts for treatment of end-stage liver disease continues to fall short of ongoing demands. Currently, most liver transplants originate from donations after brain death. Enhanced utilization of the present resources is prudent to address the needs of the population. Donation after circulatory or cardiac death is a mechanism whereby the availability of organs can be expanded. Donations after circulatory death pose unique challenges given their exposure to warm ischemia. Technical principles of donations after circulatory death procurement and pertinent studies investigating patient outcomes, graft outcomes, and complications are highlighted in this review. We also review associated risk factors to suggest potential avenues to achieve improved outcomes and reduced complications. Future considerations and alternative techniques of organ preservation are discussed, which may suggest novel strategies to enhance preservation and donor expansion through the use of marginal donors. Ultimately, without effective measures to bolster organ supply, donations after circulatory death should remain a consideration; however, an understanding of inherent risks and limitations is necessary.

A novel redox-active metalloporphyrin reduces reactive oxygen species and inflammatory markers but does not improve marginal mass engraftment in a murine donation after circulatory death islet transplantation model

Islet transplantation is a highly effective treatment for stabilizing glycemic control for select patients with type-1 diabetes. Despite improvements to clinical transplantation, single-donor transplant success has been hard to achieve routinely, necessitating increasing demands on viable organ availability. Donation after circulatory death (DCD) may be an alternative option to increase organ availability however, these organs tend to be more compromised. The use of metalloporphyrin anti-inflammatory and antioxidant (MnP) compounds previously demonstrated improved in vivo islet function in preclinical islet transplantation. However, the administration of MnP (BMX-001) in a DCD islet isolation and transplantation model has yet to be established. In this study, murine donors were subjected to a 15-min warm ischemic (WI) period prior to isolation and culture with or without MnP. Subsequent to one-hour culture, islets were assessed for in vitro viability and in vivo function. A 15-minute WI period significantly reduced islet yield, regardless of MnP-treatment relative to yields from standard isolation. MnP-treated islets did not improve islet viability compared to DCD islets alone. MnP-treatment did significantly reduce the presence of extracellular reactive oxygen species (ROS) (p < 0 .05). Marginal, syngeneic islets (200 islets) transplanted under the renal capsule exhibited similar in vivo outcomes regardless of WI or MnP-treatment. DCD islet grafts harvested 7 d post-transplant exhibited sustained TNF-α and IL-10, while MnP-treated islet-bearing grafts demonstrated reduced IL-10 levels. Taken together, 15-minute WI in murine islet isolation significantly impairs islet yield. DCD islets do indeed demonstrate in vivo function, though MnP therapy was unable to improve viability and engraftment outcomes.

Non-Heartbeating Organ Donation: A Review

Organ transplantation is one of the groundbreaking achievements in medicine in the 20th century. In the early days of transplantation, organs were obtained from non-heartbeating (NHB) cadavers. With time, better options for organ sources became available (for example, living-related and “brain dead” donors), and the practice of obtaining organs from NHB cadavers fell out of favor. Improvements in the field of transplantation have led to an increased demand for organs. Various strategies have been employed recently to increase the supply, one of them being non-heartbeating organ donation (NHBOD). NHBOD can take place in controlled or uncontrolled circum-stances. Recently, national organizations have supported and proposed guidelines for NHBOD and to aid clinicians in identifying potential donors. Outcomes of organs obtained from NHB cadavers are comparable to those obtained from heartbeating donors. The practice of NHBOD is increasing and has proven that it can contribute to increasing organ availability.

Clinical islet isolation and transplantation outcomes with deceased cardiac death donors are similar to neurological determination of death donors

In islet transplantation, deceased cardiac death (DCD) donation has been identified as a potential extended source. There are currently no studies comparing outcomes between these categories, and our goal was to compare islet isolation success rates and transplantation outcomes between DCD and neurological determination of death (NDD) donors. Islet isolations from 15 DCD and 418 NDD were performed in our centre between September 2008 and September 2014. Donor variables, islet yields, metabolic function of isolated isled and insulin requirements at 1-month post-transplant were compared. Compared to NDD, pancreata from DCD were more often procured locally and donors required less vasopressive support (P < 0.001 and P = 0.023, respectively), but the other variables were similar between groups. Pre- and postpurification islet yields were similar between NDD and DCD (576 vs. 608 × 10(3) islet equivalent, P = 0.628 and 386 vs. 379, P = 0.881, respectively). The metabolic function was similar between NDD and DCD, as well as the mean decrease in insulin requirement at 1-month post-transplantation (NDD: 64.82%; DCD: 60.17% reduction, P = 0.517). These results support the broader use of DCD pancreata for islet isolation. A much larger DCD islet experience will be required to truly determine noninferiority of both short- and long-term outcomes.

Neonatal and Pediatric Organ Donation: Ethical Perspectives and Implications for Policy

The lifesaving processes of organ donation and transplantation in neonatology and pediatrics carry important ethical considerations. The medical community must balance the principles of autonomy, non-maleficence, beneficence, and justice to ensure the best interest of the potential donor and to provide equitable benefit to society. Accordingly, the US Organ Procurement and Transplantation Network (OPTN) has established procedures for the ethical allocation of organs depending on several donor-specific and recipient-specific factors. To maximize the availability of transplantable organs and opportunities for dying patients and families to donate, the US government has mandated that hospitals refer potential donors in a timely manner. Expedient investigation and diagnosis of brain death where applicable are also crucial, especially in neonates. Empowering trained individuals from organ procurement organizations to discuss organ donation with families has also increased rates of consent. Other efforts to increase organ supply include recovery from donors who die by circulatory criteria (DCDD) in addition to donation after brain death (DBD), and from neonates born with immediately lethal conditions such as anencephaly. Ethical considerations in DCDD compared to DBD include a potential conflict of interest between the dying patient and others who may benefit from the organs, and the precision of the declaration of death of the donor. Most clinicians and ethicists believe in the appropriateness of the Dead Donor Rule, which states that vital organs should only be recovered from people who have died. The medical community can maximize the interests of organ donors and recipients by observing the Dead Donor Rule and acknowledging the ethical considerations in organ donation.

A meta-analysis and meta-regression of outcomes including biliary complications in donation after cardiac death liver transplantation

Donation after cardiac death (DCD) liver transplantation is increasingly common but concerns exist over the development of biliary complications and ischemic cholangiopathy (IC). This study aimed to compare outcomes between DCD and donation after brain death (DBD) liver grafts. Studies reporting on post-transplantation outcomes after Maastricht category III DCD liver transplantation were screened for inclusion. Odds ratios (OR) with 95% confidence intervals were produced using random-effects models for the incidence of biliary complications, IC, graft and recipient survival. Meta-regression was undertaken to identify between-study predictors of effect size for biliary complications and IC. PROSPERO Record: CRD42012002113. Twenty-five studies with 62 184 liver transplant recipients (DCD = 2478 and DBD = 59 706) were included. In comparison with DBD, there was a significant increase in biliary complications [OR = 2.4 (1.9, 3.1); P < 0.00001] and IC [OR = 10.5 (5.7, 19.5); P < 0.00001] following DCD liver transplantation. In comparison with DBD, at 1 year [OR = 0.7 (0.5, 0.8); P = 0.0002] and 3 years [OR = 0.6 (0.5, 0.8); P = 0.001], there was a significant decrease in graft survival following DCD liver transplantation. At 1 year, there was also a nonsignificant decrease [OR = 0.8 (0.6, 1.0); P = 0.08] and by 3 years a significant decrease [OR = 0.7 (0.5, 1.0); P = 0.04] found in recipient survival following DCD liver transplantation. Eleven factors were entered into meta-regression models, but none explained the variability in effect size between studies. DCD liver transplantation is associated with an increase in biliary complications, IC, graft loss and mortality. Significant unexplained differences in effect size exist between centers.

Liver transplantation for a giant mesenchymal hamartoma of the liver in an adult: Case report and review of the literature

Mesenchymal hamartomas of the liver (MHLs) in adults are rare and potentially premalignant lesions, which present as solid/cystic neoplasms. We report a rare case of orthotopic liver transplantation in a patient with a giant MHL. In 2013, a 34-year-old female sought medical advice after a 2-year history of progressive abdominal distention and respiratory distress. Physical examination revealed an extensive mass in the abdomen. Computed tomography (CT) of her abdomen revealed multiple liver cysts, with the diameter of largest cyst being 16 cm × 14 cm. The liver hilar structures were not clearly displayed. The adjacent organs were compressed and displaced. Initial laboratory tests, including biochemical investigations and coagulation profile, were unremarkable. Tumor markers, including levels of AFP, CEA and CA19-9, were within the normal ranges. The patient underwent orthotopic liver transplantation in November 2013, the liver being procured from a 40-year-old man after cardiac death following traumatic brain injury. Warm ischemic time was 7.5 min and cold ischemic time was 3 h. The recipient underwent classical orthotopic liver transplantation. The recipient operative procedure took 8.5 h, the anhepatic phase lasting for 1 h without the use of venovenous bypass. The immunosuppressive regimen included intraoperative induction with basiliximab and high-dose methylprednisolone, and postoperative maintenance with tacrolimus, mycophenolate mofetil, and prednisone. The recipient's diseased liver weighed 21 kg (dry weight) and measured 41 cm × 32 cm × 31 cm. Histopathological examination confirmed the diagnosis of an MHL. The patient did not experience any acute rejection episode or other complication. All the laboratory tests returned to normal within one month after surgery. Three months after transplantation, the immunosuppressive therapy was reduced to tacrolimus monotherapy, and the T-tube was removed after cholangiography showed no abnormalities. Twelve months after transplantation, the patient remains well and is fulfilling all normal activities. Adult giant MHL is extremely rare. Symptoms, physical signs, laboratory results, and radiographic imaging are nonspecific and inconclusive. Surgical excision of the lesion is imperative to make a definite diagnosis and as a cure. Liver transplantation should be considered as an option in the treatment of a non-resectable MHL.

Normothermic liver preservation: a new paradigm?

Despite increasing donor numbers, waiting lists and pre-transplant mortality continue to grow in many countries. The number of donor organs suitable for liver transplantation is restricted by cold preservation and ischemia-reperfusion injury (IRI). Transplantation of marginal donor organs has led to renewed interest in new techniques which have the potential to improve the quality of preservation, assess the quality of the organ and allow repair of the donor organ prior to transplantation. If successful, such techniques would not only improve the outcome of currently transplanted marginal livers, but also increase the donor pool. Experimental evidence suggests that preservation under near physiological conditions of temperature and oxygenation abrogates IRI. Normothermic perfusion maintains the organ in a physiological state, avoiding the depletion of cellular energy and the accumulation of waste products, which occurs with static cold storage. It enables viability assessment prior to transplantation thereby reducing the risk of transplanting inherently marginal organs. Here we review the use of normothermic machine perfusion as a means of organ preservation.

Review of anesthesia in liver transplantation

Liver transplantation (LT) is a well-accepted treatment modality of many end-stage liver diseases. The main issue in LT is the shortage of deceased donors to accommodate the needs of patients waiting for such transplants. Live donors have tremendously increased the pool of available liver grafts, especially in countries where deceased donors are not common. The main ethical concern of this procedure is the safety of healthy donors, who undergo a major abdominal surgery not for their own health, but to help cure others. The first part of the review concentrates on live donor selection, preanesthetic evaluation, and intraoperative anesthetic care for living liver donors. The second part reviews patient evaluation, intraoperative anesthesia monitoring, and fluid management of the recipient. This review provides up-to-date information to help improve the quality of anesthesia, and contribute to the success of LT and increase the long-term survival of the recipients.

Graft cholangiopathy: etiology, diagnosis, and therapeutic strategies

BACKGROUND

Graft cholangiopathy has been recognized as a significant cause of morbidity, graft loss, and even mortality in patients after orthotopic liver transplantation. The aim of this review is to analyze the etiology, pathogenesis, diagnosis and therapeutic strategies of graft cholangiopathy after liver transplantation.

DATA SOURCE

A PubMed database search was performed to identify articles relevant to liver transplantation, biliary complications and cholangiopathy.

RESULTS

Several risk factors for graft cholangiopathy after liver transplantation have been identified, including ischemia/reperfusion injury, cytomegalovirus infection, immunological injury and bile salt toxicity. A number of strategies have been attempted to prevent the development of graft cholangiopathy, but their efficacy needs to be evaluated in large clinical studies. Non-surgical approaches may offer good results in patients with extrahepatic lesions. For most patients with complex hilar and intrahepatic biliary abnormalities, however, surgical repair or re-transplantation may be required.

CONCLUSIONS

The pathogenesis of graft cholangiopathy after liver transplantation is multifactorial. In the future, more efforts should be devoted to the development of more effective preventative and therapeutic strategies against graft cholangiopathy.

Approach to Intraoperative Consultation for Donor Liver Biopsies

Context.— As demand for organs to treat end-stage liver disease increases, donor livers once deemed only marginally suitable for donation are being considered for transplantation. Pathologists are increasingly being asked to evaluate these livers for acceptability. This article provides guidelines for frozen section evaluation of livers for transplantation.

Objective.— This article concentrates on the histopathologic features of transplant suitability with appropriate clinicopathologic correlation for the practicing pathologist. Recommendations for proper handling and sampling of tissue are discussed. Relative and absolute contraindications as well as artifacts and benign conditions are emphasized.

Data Sources.— Sources include a compilation of the authors' experiences in academic and community liver transplantation centers. In addition, relevant medical literature was reviewed, as well as Web sites specializing in organ transplantation, such as Transplant Pathology Internet Services and the Organ Procurement and Transplantation Network.

Conclusions.— Malignancy and extensive necrosis in the liver are absolute contraindications to transplantation. Evaluation of macrosteatosis, fibrosis, hepatitis, and necrosis depends on the severity of disease and correlation with the clinical situation. Donor age of greater than 60 years does not preclude transplantation. Artifacts and benign conditions need to be understood to prevent wastage of precious organs and to ensure that an appropriate organ is provided for the recipient.

Categories of donation after cardiocirculatory death

The interest in donation after cardiocirculatory death (DCD) was renewed in the early 1990s, as a means to partially overcome the shortage of donations after brain death. In some European countries and in the United States, DCD has become an increasingly frequent procedure over the last decade. To improve the results of DCD transplantation, it is important to compare practices, experiences, and results of various teams involved in this field. It is therefore crucial to accurately define the different types of DCD. However, in the literature, various DCD terminologies and classifications have been used, rendering it difficult to compare reported experiences. The authors have presented herein an overview of the various DCD descriptions in the literature, and have proposed an adapted DCD classification to better define the DCD processes, seeking to provide a better tool to compare the results of published reports and to improve current practices. This modified classification may be modified in the future according to ongoing experiences in this field.

Recipient and perioperative risk factors associated with liver transplant graft outcomes

BACKGROUND

Orthotopic liver transplantation (OLT) is currently considered to be the ultimate form of therapy for most patients with end-stage liver diseases. The identification of recipient and various perioperative factors that may affect the graft outcomes is critical. This study sought to analyze the preoperative and perioperative factors associated with graft outcomes in our institute.

METHODS

This retrospective study of liver transplanted patients from January 2002 to December 2009 determined the incidence of 2 forms of primary dysfunction (PDF): Primary nonfunction (PNF) and initial poor function (IPF).

RESULTS

The 97 posttransplant patients included in the study had an average age of 52.74 years. The majority of indications for OLT were hepatitis B and/or C cirrhosis, alcoholic cirrhosis, and hepatocellular carcinoma. The incidence of PDF was 31.9% (31/97) with 7.2% (7/97) PNF and 24.7% (24/97) IPF. Additionally, we observed 68.1% (66/97) to display immediate function (IF). Warm ischemic time (WIT) and operative time were significantly longer in the PDF compared with the IF group. The logistic regression model showed a WIT of >45 minutes to be a risk factor leading to PDF (odds ratio, 11.74; P<.05). An operative time of >6 hours and operative blood loss of >2 L were possible risk factors.

CONCLUSION

Prolonged WIT (>45 minutes) was the only significant risk factor among other established parameters for graft function. Nevertheless, reduced operative times and blood loss may improve the outcomes of OLT.

Resource implications of expanding the use of donation after circulatory determination of death in liver transplantation

In the United Kingdom, liver transplantation using donation after circulatory determination of death (DCDD) organs has increased steadily over the last few years and now accounts for 20% of UK transplant activity. The procurement of DCDD livers is actively promoted as a means of increasing the donor pool and bridging the evolving disparity between the wait-list length and the number of transplants performed. The objective of this retrospective study of a cohort of patients who were matched for age, liver disease etiology, and Model for End-Stage Liver Disease score was to determine whether differences in perioperative costs and resource utilization are associated with the use of such organs. Our results showed an increased prevalence of reperfusion syndrome in the DCDD cohort (P < 0.001), a prolonged heparin effect (P = 0.01), a greater incidence of hyperfibrinolysis (P = 0.002), longer periods of postoperative ventilator use (P = 0.03) and vasopressor support (P = 0.002), and a prolonged length of stay in the intensive therapy unit (ITU; P = 0.02). The peak posttransplant aspartate aminotransferase level was higher in the DCDD group (P = 0.007), and there was significantly more graft failure at 12 months (P = 0.03). In conclusion, we have demonstrated different perioperative and early postoperative courses for DCDD and donation after brain death (DBD) liver transplants. The overall quality of DCDD grafts is poorer; as a result, the length of the ITU stay and the need for multiorgan support are increased, and this has significant financial and resource implications. We believe that these implications require a careful real-life consideration of benefits. It is essential for DCDD not to be seen as a like-for-like alternative to DBD and for every effort to be continued to be made to increase the number of donations from brain-dead patients as a first resort.

Liver transplantation using Donation after Cardiac Death donors

The success of solid organ transplantation has brought about burgeoning waiting lists with insufficient donation rates and substantial waiting list mortality. All countries have strived to expand donor numbers beyond the standard Donation after Brain Death (DBD). This has lead to the utilization of Donation after Cardiac Death (DCD) donors, also frequently referred to as Non-Heart Beating Donors (NHBD). Organs from these donors inevitably sustain warm ischaemic damage which varies in its extent and affects early graft function as well as graft survival. As a consequence, 'non-vital' organs such as renal transplants have increased rapidly from DCD donors but more 'vital' organ transplants such as the liver have lagged behind. However, an increasing proportion of liver transplants are now derived from DCD donors. This article covers this expansion, current results, pitfalls, and steps taken to minimize complications and to improve outcome, and future developments that are likely to occur.

Biliary complications after liver transplantation from donation after cardiac death donors: an analysis of risk factors and long-term outcomes from a single center

OBJECTIVE

This study evaluates the long-term outcomes, biliary complication rates, and risk factors for biliary complications after liver transplantation from "donation after cardiac death" (DCD) donors.

BACKGROUND

Recent enthusiasm toward increased use of DCD donors' livers is mitigated by high biliary complication rates. Predictive risk factors for the development of biliary complications after DCD liver transplantation remain incompletely defined.

METHODS

We performed a retrospective review of 1157 "donation after brain death" (DBD) and 87 DCD liver transplants performed between January 1, 1993, and December 31, 2008. Patient and graft survivals and complication rates within the first year of transplantation were compared between DBD and DCD groups. Cox proportional hazards models were used to assess the influence of potential risk factors.

RESULTS

Patient survival was significantly lower in the DCD group compared with the DBD group at 1, 5, 10, and 15 years (DCD: 84%, 68%, 54%, and 54% vs DBD: 91%, 81%, 67%, and 58%; P < 0.01). Graft survival was also significantly lower in the DCD group compared with the DBD group at 1, 5, 10, and 15 years (DCD: 69%, 56%, 43%, 43% vs DBD: 86%, 76%, 60%, 51%; P < 0.001). Rates of overall biliary complications (OBC) (DCD: 47% vs DBD: 26%; P < 0.01) and ischemic cholangiopathy (IC) (DCD: 34% vs DBD: 1%; P < 0.01) were significantly higher in the DCD group. Donor age [hazard ratio (HR): 1.04; P < 0.01] and donor age greater than 40 years (HR: 3.13; P < 0.01) were significant risk factors for the development of OBC. Multivariate analysis revealed that cold ischemic time (CIT) greater than 8 hours (HR: 2.46; P = 0.05) and donor age greater than 40 years (HR: 2.90; P < 0.01) significantly increased the risk of IC.

CONCLUSIONS

Long-term patient and graft survival after DCD liver transplantation remain significantly lower but acceptable when compared with DBD liver transplantations. Donor age and CIT greater than 8 hours are the strongest predictors for the development of IC. Careful selection of younger DCD donors and minimization of CIT may limit the incidence of severe biliary complications and improve the successful utilization of DCD donors' livers.

Hepatic steatosis is not always a contraindication for cadaveric liver transplantation

BACKGROUND

Macrovesicular steatosis is assumed to be an important risk factor for early allograft dysfunction (EAD) after orthotopic liver transplantation (OLT).

AIM

To evaluate the impact of steatosis in combination with other risk factors on the outcome of OLT.

METHODS

The degree of steatosis was analysed in 165 consecutive OLTs and was classified by histological examination as non (M0), mild (<30%, M1), moderate (30-60%, M2) or severe steatosis (>60%, M3). Recipients were analysed for EAD.

RESULTS

EAD was observed in 28% of patients with M0, 26% with M1, 53% with M2 and 73% with M3 (P < 0.001). Patients with EAD had a significantly shorter graft survival after liver transplantation (P = 0.005) but did not correlate with survival. In multivariate regression analysis, the grade of steatosis, donating after cardiocirculatory death (DCD) grafts and duration of cold ischaemia time were significantly associated with EAD (P < 0.001, P = 0.01 and P = 0.001, respectively).

CONCLUSION

Livers with severe (M3) steatosis from DCD donors, combined with a prolonged CIT have a high risk for developing EAD which is correlated with shorter graft survival. Therefore M3 livers should only be considered for OLT in selected recipients without the presence of additional risk factors.

Simultaneous liver and kidney transplantation using donation after cardiac death donors: a brief report

Although the use of donation after cardiac death (DCD) donor organs has been shown to be a viable option for liver and kidney transplant recipients, outcomes after simultaneous liver and kidney (SLK) transplantation using DCD donors are less clear. We performed a retrospective analysis of 37 adult, primary SLK transplants performed at our center between January 1, 1998 and December 31, 2008. Thirty-two patients received donation after brain death (DBD) organs, and 5 patients received DCD organs. SLK recipients in the 2 groups were similar with respect to age, gender, race, body mass index, donor race, and donor body mass index. The calculated Model for End-Stage Liver Disease scores and pretransplant glomerular filtration rates were similar between the groups. DCD donors were younger and had shorter liver cold ischemia times. The median DCD donor warm ischemia time was 19.0 minutes (6.0-25.0 minutes). The recipient surgical times and hospital lengths of stay were comparable between the groups. Delayed graft function was more frequent in DCD renal allografts (80% versus 31%, P = 0.06). The 1-year graft survival rates for liver allografts (100% for the DCD group versus 94% for the DBD group) and kidney allografts (100% for the DCD group versus 94% for the DBD group) were similar. In conclusion, patients undergoing DCD SLK transplantation have comparable 1-year patient and graft survival rates and acceptable perioperative morbidity in comparison with DBD SLK transplant recipients. Although long-term outcomes remain unknown, the utilization of DCD organs for SLK transplantation should be considered a valid approach to safely expanding the donor organ pool.

Use of a third-generation perfluorocarbon for preservation of rat DCD liver grafts

BACKGROUND

Cold storage in any of the commonly used preservation solutions is not always adequate for donation after cardiac death (DCD) liver grafts due to prolonged warm ischemic time. In this study, we used a third-generation perfluorocarbon (PFC), Oxycyte, for DCD liver graft preservation in a rat model.

MATERIALS AND METHODS

Twenty-eight rats (14 in each group) were used. Thirty minutes after cardiopulmonary arrest, livers were harvested and flushed with a cold and pre-oxygenated solution of either University of Wisconsin (UW) or UW + 20% PFC. After 8 h of cold preservation in either of the investigated solutions, liver graft specimens were analyzed for evidence of ischemic injury. Hemotoxylin and eosin staining (H and E), as well as immunohistochemical analysis with anti-cleaved caspase 3 antibody, was performed. Levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in the preservation solution were analyzed at 1 and 8 h during preservation.

RESULTS

In the PFC group, the degree of cell congestion, vacuolization and necrosis were all significantly less than in the UW group (P = 0.002-0.004). The number of cells with a positive cleaved caspase 3 antibody reaction was reduced by about 50% in comparison with the UW group (P < 0.006). The AST level in the PFC group was significantly less than in the UW group after 8 h of preservation (P < 0.048).

CONCLUSION

The addition of PFC to UW solution significantly decreases the degree of histologic damage in rat DCD liver grafts. This preservation strategy can be potentially helpful for organ preservation after prolonged warm ischemia.

Biliary complications after orthotopic liver transplantation from donors after cardiac death: broad spectrum of disease

BACKGROUND

Donation-after-death liver transplantation (DCD-LT) carries higher complication rates compared with donation-after-brain death liver transplantation (DBD-LT). In this report we describe our experience with biliary complications in DCD-LT with emphasis on anatomical patterns and outcomes.

MATERIALS AND METHODS

We performed retrospective review of patients' medical records from August 2004 to December 2008, during which time total of 26 DCD-LTs were performed. Mean follow-up was 29 months (range 3 to 51 months).

RESULTS

Biliary complications occurred in 12 patients (46%), of whom 9 were related to DCD (35%). Four patients had more than 1 biliary complication, and 4 had concomitant arterial problems (stricture/thrombosis). Treatment of complications included: ERCP (n = 5, 3 resolved), conversion to roux (n = 5, 2 resolved), revision of roux (n = 1), percutaneous transhepatic cholangiography (n = 1), artery revision (n = 3). Three patients with casts had operative extraction of casts depicting a mummified biliary tree; histology showed casts and fibrosis and anastomotic suture material. Six patients underwent retransplantation (23%). Among retransplanted patients, 2 deaths occurred (7.7%).

CONCLUSION

Our experience with DCD-LT reveals a high prevalence of biliary complications with a new and wide spectrum of clinicopathologic findings. Better strategies for prevention of these unique biliary complications are needed to better justify the added risks and costs for performance of DCD-LT.

Machine perfusion at 20°C reduces preservation damage to livers from non-heart beating donors

We previously reported that machine perfusion (MP) performed at 20°C enhanced the preservation of steatotic rat livers. Here, we tested whether rat livers retrieved 30 min after cardiac arrest (NHBDs) were better protected by MP at 20°C than with cold storage. We compared the recovery of livers from NHBDs with organs obtained from heart beating donors (HBDs) preserved by cold storage. MP technique: livers were perfused for 6h with UW-G modified at 20°C. Cold storage: livers were perfused in situ and preserved with UW solution at 4°C for 6h. Both MP and cold storage preserved livers were reperfused with Krebs-Heinselet buffer (2h at 37°C). AST and LDH release and mitochondrial glutamate dehydrogenase (GDH) levels were evaluated. Parameters assessed included: bile production and biliary enzymes; tissue ATP; reduced and oxidized glutathione (GSH/GSSG); protein-SH group concentration. Livers preserved by MP at 20°C showed significantly lower hepatic damage at the end of reperfusion compared with cold storage. GDH release was significantly reduced and bile production, ATP levels, GSH/GSSG and protein-SH groups were higher in livers preserved by MP at 20°C than with cold storage. The best preserved morphology and high glycogen content was obtained with livers submitted to MP at 20°C. Liver recovery using MP at 20°C was comparable to recovery with HBDs. MP at 20°C improves cell survival and gives a better-quality of preservation for livers obtained from NHBDs and may provide a new method for the successful utilization of marginal livers.

Strategies for widening liver donor pool

Liver transplantation is a life-saving treatment modality, but is hindered by the scarcity of deceased-donor liver grafts. To acquire more liver grafts and thus save more lives, various techniques have been devised and policies adopted, including living-donor, split-graft and sequential liver transplantation; extended donor criteria; and donation after cardiac death. However, with these techniques and policies come a range of entailed medical concerns and concomitant ethical dilemmas, mainly bearing on the welfare of donors and potential donors. In this article, we provide an overview of how the transplant community works towards the end of extending the liver donor pool, with the aim of ensuring that more liver transplant candidates receive their transplant as early as possible. The current strategies in Hong Kong in this regard are also reviewed.

No synergistic effect of carbon monoxide and oxygen during static gaseous persufflation preservation of DCD livers

OBJECTIVE

The benefit of carbon monoxide and/or oxygen as applied by controlled, continuous gaseous persufflation during liver preservation on postischemic graft recovery was investigated in an isolated rat liver model.

METHODS

Livers from male Wistar rats were retrieved 30 min after cardiac arrest of the donor and subjected to 18 h of cold storage. Some grafts were subjected to gaseous persufflation during static cold storage either with pure oxygen or with CO dissolved in oxygen. Graft integrity was assessed thereafter upon warm reperfusion in vitro.

RESULTS

Oxygen persufflation significantly reduced cellular enzyme loss and metabolic recovery (bile production and ATP recovery) upon reperfusion by about 50%. The effect was associated with a reduction of vascular perfusion resistance, mitigated gene up-regulation of the mitochondrial stress protein GRP 75, and improved mitochondrial ultra-structure. Similar results were obtained by persufflation with CO in oxygen, while no additive benefit of CO and oxygen could be seen in our model.

CONCLUSION

Hepatocellular injury of cold stored liver grafts can be notably reduced by gaseous ex vivo application of oxygen with or without additional admixture of CO to the isolated organ but no superiority or additive effect is seen with respect to persufflation with oxygen.

Ex-vivo normothermic liver perfusion: an update

PURPOSE OF REVIEW

There is increasing disparity between the supply of acceptable donor organs and the number of potential transplant recipients. The shortage of organs for transplantation demands optimal utilization of a wider spectrum of donor organs, including nonheart-beating and other extended criteria donors. In the case of the liver, a substantial number of organs are discarded because of a risk of primary nonfunction.

RECENT FINDINGS

For many years hypothermic preservation has been the universal standard for organ preservation. Although limited in terms of the duration of preservation it has had the major advantages of simplicity, portability and affordability. Organ preservation by normothermic machine perfusion has repeatedly proven superiority over static cold storage in experimental settings. However, it is complex and costly and its place in clinical transplantation has not yet been established. In liver preservation normothermic perfusion provides the potential: (a) to preserve extended criteria grafts for long periods; (b) to assess the viability of these grafts during perfusion; and (c) to improve the condition of the grafts.

SUMMARY

Avoidance of cold ischaemic preservation damage and repair of injury sustained during warm ischaemia and organ procurement would potentially allow many livers from extended criteria donors to be transplanted reliably. The current challenges are, first to confirm the feasibility of the normothermic machine perfusion methodology in human livers and, second, to develop and introduce a functional device into the clinical arena.

Liver transplantation in children using non-heart-beating donors (NHBD)

Selected livers from controlled NHBD are accepted for OLT in adults. Recent evidence has shown good medium-term outcome. The purpose of this study was to report our experience of pediatric OLT with whole and partial grafts from NHBD, analyzing complications and outcome. Retrospective review of all the recipients who underwent primary OLT between December 2005 and December 2008, using livers from NHBD. Four children (one male child) mean age was 9.5 yr (0.2-17), mean weight was 26 kg (range 2.6-48), underwent OLT using NHBD. Mean donor age was 14.2 yr, and mean WIT (systolic BP<50 mmHg to cold perfusion) 12.2 min (range 10-15). Two children received reduced grafts and two full grafts. Mean cold ischemia time was 7.18 h (range 6-8). Liver function tests one wk and nine months post-OLT confirmed a good graft function. One child was treated for two episodes of acute rejection. Post-transplant complications included two cases of mild ischemic cholangiopathy treated conservatively. Graft and patient survival was 100% with a mean follow-up of 19 months (range 8.1-43.4). Short- to medium-term follow-up suggests that liver grafts from young NHBD with short warm and cold ischemia times can be safely utilized in pediatric transplantation.

A single center experience of donation after cardiac death liver transplantation in pediatric recipients

Many centers are now performing DCD adult LT. There has been a reluctance to transplant pediatric recipients with DCD livers due to concern over the medium to long-term outcome. We describe the outcome of 14 children (median age seven yr, 8 months-16 yr) that underwent LT with DCD grafts from July 2001 to December 2007. Donors had a median age of 23 yr (10-64), intensive care stay of five d (2-14) and bilirubin of 9 mmol/L (6-60). Median warm and cold ischemic time was 16 min (11-29) and seven h (5.5-8.4). Livers were transplanted as a whole organ (4), reduced graft (8), formal split (1) or auxiliary transplant (1). Compared to DBD recipients AST was significantly higher on the first three post-operative days and there was no difference in the INR, bilirubin or GGT out to 12 months. There were no biliary or vascular complications and patient and graft survival is 100% at a median follow-up of 41.8 months (1.7-74 months). LT with DCD grafts in pediatric recipients can be performed with low morbidity and excellent short-to-medium term patient and graft outcome.