Split liver transplantation

Acute Liver Failure in Children

Acute liver failure (ALF) in children, irrespective of cause, is a rapidly evolving catastrophic clinical condition that results in high mortality and morbidity without prompt identification and intervention. Massive hepatocyte necrosis impairs the synthetic, excretory, and detoxification abilities of the liver, with resultant coagulopathy, jaundice, metabolic disturbance, and encephalopathy. Extrahepatic organ damage, multiorgan failure, and death result from circulating inflammatory mediators released by the hepatocytes undergoing necrosis. There are yet no treatment options available for reversing or halting hepatocellular necrosis, thus current therapy focuses on supporting failing organs and preventing life threatening complications pending either spontaneous liver recovery or transplantation. The aims of this review are to define pediatric acute liver failure (PALF), understand the pathophysiologic processes that lead to multiorgan failure, to describe the consequences of a failing liver on extrahepatic organs, to enumerate the critical care challenges encountered during PALF management, and to describe pharmacologic and extracorporeal options available to support a critically ill child with ALF in the intensive care unit.

Addressing the challenges of split liver transplantation through technical advances. A systematic review

BACKGROUND

Split liver transplantation addresses donor shortages by facilitating the transplant of two recipients using one donor liver. Some still consider these grafts inferior due to prolonged cold ischaemia time and at times difficult vascular reconstruction. Techniques such as in-situ splitting, machine perfusion and interposition grafts may address these challenges and thereby address these concerns. The aim of this review is to assess these technical advances in split liver transplantation, their utility and outcomes.

METHODS

A systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Keywords included 'split liver transplantation', 'arterial reconstruction', and 'machine perfusion'. Data found was synthesised into sections including: methods of splitting, full-left full-right splitting, donor cholangiography, machine perfusion and arterial reconstruction.

RESULTS

A total of 78 articles met inclusion criteria after screening of 151 eligible articles. These were subdivided into the following categories: in-situ (25), ex-vivo (25), full-left full-right splitting (15), donor cholangiography (2), machine perfusion (6), and arterial reconstruction (5). The in-situ splitting technique reduces the cold ischaemia time compared to the ex-vivo technique which may improve graft quality and liver splitting during normothermic machine perfusion is a novel technique with the potential to incorporate the best aspects of both techniques. Interposition grafts are often required during split liver transplantation but have an increased risk of hepatic artery thrombosis.

CONCLUSION

Advancements in technique have allowed many of the unique challenges of split liver transplantation to be overcome. Overall, this supports the use of split liver transplantation in broader and riskier settings and we advocate for liver transplant surgeons to not hesitate in using these grafts liberally and expanding their recipient selection criteria.

Applicability of Hypothermic Oxygenate Machine Perfusion Preservation for Split-Liver Transplantation in a Porcine Model: An Experimental Study

Background

Split-liver transplantation can be useful in situations of limited donor resources. However, novel preservation methods are required to help the recipient recover from severe ischemic reperfusion injury incurred due to receiving a relatively small liver graft.

Material/Methods

Our experiment was performed using porcine livers without warm ischemia time, assuming a brain-dead organ. We made porcine split-liver grafts by 75% liver resection at the back table and divided the specimens into 4 groups. Group 1 was preserved with simple cold storage after splitting (CS; n=3), Group 2 was preserved with hypothermic perfusion preservation (HMP) after splitting (SBP; n=3), Group 3 was preserved with HMP after splitting under perfusion preservation (SDP; n=4), and Group 4 had the whole liver perfused as control grafts (Whole Liver; n=3). To assess potential methods of preservation and their effects, all grafts were evaluated by an ex vivo isolated liver reperfusion model using diluted autologous blood.

Results

Portal vein pressure resistances during reperfusion were low in Group3 (SDP). Hepatic artery pressure resistances during reperfusion were markedly higher in Group 1(CS) than in the other groups. The levels of AST and LDH were high and increased at 2 h after reperfusion in Group 1 (CS). The histological findings show that the liver cell structure was irregular in Group 1 (CS) but remained regular in Groups 2 (SBP) and 3 (SDP). Histological Suzuki scores were also significantly better in Groups 2 (SBP) and 3 (SDP) compared with Group 1 (CS).

Conclusions

Splitting the liver under machine perfusion preservation may help restore the function and reduce ischemia-reperfusion injury.

Normothermic Machine Perfusion Protects Against Liver Ischemia-Reperfusion Injury During Reduced-Size Liver Transplantation in Pigs

Background

Normothermic machine perfusion (NMP) preservation is superior to cold preservation during reduced-size liver transplantation (RSLT) in pigs. However, the mechanism of this protective effect has not been explained. We aimed to compare the effects of NMP preservation with that of cold preservation (CS) in protecting against ischemia-reperfusion injury (IRI) during RSLT in pigs.

Material/Methods

Twenty-four healthy Bama miniature pigs were randomized into 2 groups: 1) the NMP group in which donor livers harvested without warm ischemia time and cardiac activity were connected to the NMP system to reduce liver size under normothermic conditions, and 2) the CS group in which donor livers harvested without warm ischemia time and cardiac activity were perfused using the University of Wisconsin (UW) solution and then preserved in the 0–4°C UW solution to reduce liver size under cold conditions. Livers were then transplanted without veno-venous bypass. Amounts of bile secretion for the NMP groups were recorded hourly. The serological indices were measured. Expressions of cytochrome C, caspase 3, and NF-κB p65 in liver tissue were observed.

Results

The levels of bile secretions were gradually diminished from 16.50±2.66 mL/h before splitting to 6.35±1.24 mL/h after splitting. With the exception of TNF-α on postoperative day 2, overall, levels of TNF-α, IL-1, IL-6, and MDA were significantly lower in the NMP group versus CS group for all 5 days postoperatively. Finally, cytochrome C, caspase 3, and NF-κB p65 expressions were all significantly suppressed in the NMP group as compared with the CS group.

Conclusions

MP preservation is superior to cold preservation in protecting against liver IRI during RSLT in pigs.

Domino Hepatocyte Transplantation: A Therapeutic Alternative for the Treatment of Acute Liver Failure

BACKGROUND AND AIMS

Acute liver failure (ALF) is a severe syndrome with an elevated mortality rate, ranging from 40 to 80 %. Currently, liver transplantation is the only definitive treatment for these patients and new therapies aiming to treat ALF include artificial organs implant and stem cells therapy, for example. However, a major limitation of liver donors exists. Living donor liver transplantation (LDLT), split liver transplantation (SLT), and domino liver transplantation (DLT) are some of the available alternatives to treat ALF patients, but these do not reduce the number of patients on waiting lists. Herein, we discuss domino hepatocyte transplantation (DHT) using livers that would not meet transplantation criteria.

METHODS

We conducted a literature search on PubMed/Medline using acute liver failure, liver transplantation, hepatocyte transplantation, and domino liver transplantation as key words.

RESULTS

New sources of biochemically functional hepatocytes and therapeutic treatments, in parallel to organ transplantation, may improve liver injury recovery and decrease mortality rates. Moreover, the literature reports hepatocyte transplantation as a therapeutic alternative for organ shortage. However, a major challenge remains for a wide clinical application of hepatocytes therapy, i.e., the availability of sufficient amounts of cells for transplantation. Ideally, hepatocytes isolated from livers rejected for transplantation may be a promising alternative for this problem.

CONCLUSION

Our review suggests that DHT may be an excellent strategy to increase cell supplies for hepatocyte transplantation.

A matched pair analysis of multicenter longterm follow-up after split-liver transplantation with extended right grafts

Split-liver transplantation has been proposed as an alternative to whole liver (WL) transplantation to expand the donor pool, but studies comparing adult longterm outcomes between the 2 methods are conflicting and limited. This is the first Italian multicenter study that retrospectively analyzed 119 matched-pair recipients of whole and extended right grafts (ERGs) for longterm survival outcomes. In the overall population, WL recipients showed higher patient survival at 1 (93% versus 73%), 5 (87% versus 65%), and 10 years (83% versus 60%) after transplantation compared with split-liver recipients (P < 0.001); graft survivals of WL recipients were also superior at 1 (90% versus 76%), 5 (84% versus 57%), and 10 years (81% versus 52%) posttransplant (P < 0.001). However, among the 81 matched pairs that survived the first posttransplant year, 5- and 10-year patient survivals were 90% and 81% for split recipients and 99% and 96% for whole recipients, respectively (P = 0.34). The 5- and 10-year graft survivals were also comparable: 87% and 77% for split recipients, and 86% and 82% for whole recipients (P = 0.86). Cox regression analysis identified donor age >50, donor-to-recipient weight ratio < 1, retransplantation status, and United Network for Organ Sharing I-IIA status as risk factors for partial graft use. There were no significant differences in 5-year outcomes based on center volume. In conclusion, we demonstrate that adult liver transplantation with ERGs can achieve longterm success comparable with that of whole grafts in appropriate patients but should be selectively used in patients with risk factors. Liver Transplantation 23 1384-1395 2017 AASLD.

Protective role of normothermic machine perfusion during reduced-size liver transplantation in pigs

The purpose of this study is to explore whether normothermic machine perfusion (NMP) preservation is superior to cold preservation during reduced-size liver transplantation (RSLT) in pigs. Twenty-four healthy Ba-Ma mini pigs were used (aged >13 months; weight 25-35 kg; regardless of sex). The animals were randomized into 2 groups. In group A (NMP), donor livers were harvested without warm ischemia time and heartbeats and then were connected to the NMP system to reduce the livers' size under the normothermic condition. In group B (University of Wisconsin [UW] solution), donor livers were harvested without warm ischemia time and heartbeats after being perfused by UW solution and were then preserved in 0°C-4°C UW solution to reduce the livers' size under cold conditions. After that, liver transplantation without venovenous bypass was performed. General RSLT information of the pigs from the 2 groups was recorded; the serological indices were measured; and routine pathological examination of liver tissue was observed. A significant difference was observed in the intraoperative bleeding between the 2 groups (P < 0.05), whereas no significant difference was found in the other indices (all P > 0.05). Significant differences of alanine aminotransferase levels, aspartate aminotransferase levels, and lactate dehydrogenase levels between the 2 groups were observed between postoperative days 3 and 5 (P < 0.05). Significant differences of lactic acid levels between the 2 groups were observed between postoperative days 2 and 5 (P < 0.05). Compared with the cold preservation group, the liver tissues of the NMP preservation group only rarely experienced liver cell necrosis and maintained integrities in the hepatic sinusoid spaces and endothelial cells. In conclusion, NMP preservation is superior to cold preservation during RSLT in pigs. Liver Transplantation 22 968-978 2016 AASLD.

Long-term results after adult ex situ split liver transplantation since its introduction in 1987

BACKGROUND

Split liver transplantation is still discussed controversially. Utilization of split liver grafts has been declining since a change of allocation rules for the second graft abolished incentives for German centres to perform ex situ splits. We therefore analysed our long-term experiences with the first ex situ split liver transplant series worldwide.

METHODS

A total of 131 consecutive adult ex situ split liver transplants (01.12.1987-31.12.2010) were analysed retrospectively.

RESULTS

Thirty-day mortality rates and 1- and 3-year patient survival rates were 13, 76.3, and 66.4 %, respectively. One- and three-year graft survival rates were 63.4 and 54.2 %, respectively. The observed 10-year survival rate was 40.6 %. Continuous improvement of survival from era 1 to 3 was observed (each era: 8 years), indicating a learning curve over 24 years of experience. Patient and graft survival were not influenced by different combinations of transplanted segments or types of biliary reconstruction (p > 0.05; Cox regression). Patients transplanted for primary sclerosing cholangitis had better survival (p = 0.021; log-rank), whereas all other indications including acute liver failure (13.6 %), acute and chronic graft failure (9.1 %) had no significant influence on survival (p > 0.05; log-rank). Biliary complications (27.4 %) had no significant influence on patient or graft survival (p > 0.05; log-rank). Hepatic artery thrombosis (13.2 %) had a significant influence on graft survival but not on patient survival (p = 0.002, >0.05, respectively; log-rank).

CONCLUSIONS

Split liver transplantation can be used safely and appears to be an underutilized resource that may benefit from liberal allocation of the second graft.

Mesenchymal stem cells promote liver regeneration and prolong survival in small-for-size liver grafts: involvement of C-Jun N-terminal kinase, cyclin D1, and NF-κB

Background

The therapeutic potential of mesenchymal stem cells (MSCs) has been highlighted recently for treatment of acute or chronic liver injury, by possibly differentiating into hepatocyte-like cells, reducing inflammation, and enhancing tissue repair. Despite recent progress, exact mechanisms of action are not clearly elucidated. In this study, we attempted to explore whether and how MSCs protected hepatocytes and stimulated allograft regeneration in small-for-size liver transplantation (SFSLT).

Methods

SFSLT model was established with a 30% partial liver transplantation (30PLT) in rats. The differentiation potential and characteristics of bone marrow derived MSCs were explored in vitro. MSCs were infused transvenously immediately after graft implantation in therapy group. Expressions of apoptosis-, inflammatory-, anti-inflammatory-, and growth factor-related genes were measured by RT-PCR, activities of transcription factors AP-1 and NF-κB were analyzed by EMSA, and proliferative responses of the hepatic graft were evaluated by immunohistochemistry and western blot.

Results

MSCs were successfully induced into hepatocyte-like cells, osteoblasts and adipocytes in vitro. MSCs therapy could not only alleviate ischemia reperfusion injury and acute inflammation to promote liver regeneration, but also profoundly improve one week survival rate. It markedly up-regulated the mRNA expressions of HGF, Bcl-2, Bcl-XL, IL-6, IL-10, IP-10, and CXCR2, however, down-regulated TNF-α. Increased activities of AP-1 and NF-κB, as well as elevated expressions of p-c-Jun, cyclin D1, and proliferating cell nuclear antigen (PCNA), were also found in MSCs therapy group.

Conclusion

These data suggest that MSCs therapy promotes hepatocyte proliferation and prolongs survival in SFSLT by reducing ischemia reperfusion injury and acute inflammation, and sustaining early increased expressions of c-Jun N-terminal Kinase, Cyclin D1, and NF-κB.

Deceased-donor split-liver transplantation in adult recipients: is the learning curve over?

BACKGROUND

Infants have the highest wait-list mortality of all liver transplantation candidates. Deceased-donor split-liver transplantation, a technique that provides both an adult and pediatric graft, might be the best way to decrease this disproportionate mortality. Yet concern for an increased risk to adult split recipients has discouraged its widespread adoption. We aimed to determine the current risk of graft failure in adult recipients after split-liver transplantation.

STUDY DESIGN

United Network for Organ Sharing data from 62,190 first-time adult recipients of deceased-donor liver transplants (1995-2010) were analyzed (889 split grafts). Bivariate risk factors (p < 0.2) were included in Cox proportional hazards models of the effect of transplant type on graft failure.

RESULTS

Split-liver recipients had an overall hazard ratio of graft failure of 1.26 (p < 0.001) compared with whole-liver recipients. The split-liver hazard ratio was 1.45 (p < 0.001) in the pre-Model for End-Stage Liver Disease era (1995-2002) and 1.10 (p = 0.28) in the Model for End-Stage Liver Disease era (2002-2010). Interaction analyses suggested an increased risk of split-graft failure in status 1 recipients and those given an exception for hepatocellular carcinoma. Excluding higher-risk recipients, split and whole grafts had similar outcomes (hazard ratio = 0.94; p = 0.59).

CONCLUSIONS

The risk of graft failure is now similar between split and whole-liver recipients in the vast majority of cases, which demonstrates that the expansion of split-liver allocation might be possible without increasing the overall risk of long-term graft failure in adult recipients. Additional prospective analysis should examine if selection bias might account for the possible increase in risk for recipients with hepatocellular carcinoma or designated status 1.

Deceased donor liver transplantation in infants and small children: are partial grafts riskier than whole organs?

Infants have the highest wait-list mortality of all liver transplant candidates. Although previous studies have demonstrated that young children may be at increased risk when they receive partial grafts from adult and adolescent deceased donors (DDs), with few size-matched organs available, these grafts have increasingly been used to expand the pediatric donor pool. We aimed to determine the current adjusted risks of graft failure and mortality in young pediatric recipients of partial DD livers and to determine whether these risks have changed over time. We analyzed 2683 first-time recipients of DD livers alone under the age of 24 months in the United Network for Organ Sharing database (1995-2010), which included 1118 partial DD livers and 1565 whole DD organs. Transplant factors associated with graft loss in bivariate analyses (P < 0.1) were included in multivariate proportional hazards models of graft and patient survival. Interaction analysis was used to examine risks over time (1995-2000, 2001-2005, and 2006-2010). Although there were significant differences in crude graft survival by the graft type in 1995-2000 (P < 0.001), graft survival rates with partial and whole grafts were comparable in 2001-2005 (P = 0.43) and 2006-2010 (P = 0.36). Furthermore, although the adjusted hazards for partial graft failure and mortality were 1.40 [95% confidence interval (CI) = 1.05-1.89] and 1.41 (95% CI = 0.95-2.09), respectively, in 1995-2000, the adjusted risks of graft failure and mortality were comparable for partial and whole organs in 2006-2010 [hazard ratio (HR) for graft failure = 0.81, 95% CI = 0.56-1.18; HR for mortality = 1.02, 95% CI = 0.66-1.71]. In conclusion, partial DD liver transplantation has become less risky over time and now has outcomes comparable to those of whole liver transplantation for infants and young children. This study supports the use of partial DD liver grafts in young children in an attempt to significantly increase the pediatric organ pool.

Suppression of liver regeneration affects hepatic graft survival in small-for-size liver transplantation in rats

AIM

  Small-for-size liver transplantation (SFSLT) often results in hepatic graft failure and decreased survival. The present study was aimed to investigate the possible mechanism of hepatic graft failure in SFSLT in rats.

METHODS

  Rat models of full-size orthotopic liver transplantation, 50% partial liver transplantation and 30% partial liver transplantation were established. Proliferative responses of the hepatic graft were evaluated by immunohistochemical staining and western blotting. Apoptosis-, inflammatory-, anti-inflammatory- and growth factor-related genes were screened by quantitative reverse transcription polymerase chain reaction. Activities of transcription factors of AP-1 and nuclear factor (NF)-κB were analyzed by electrophoretic mobility shift assay.

RESULTS

  A 30% partial liver transplant not only resulted in marked structural damages to the hepatic graft, but also showed the lowest 7-day survival rate. In addition, sup pressed expressions of proliferating cell nuclear antigen (PCNA) and cyclin D1 by immunohistochemical staining and decreased expressions of cyclin D1 and p-c-Jun by western blotting were detected. Downregulated expressions of Bcl-2, Bcl-XL, interleukin (IL)-6, IL-10, IP-10 and CXCR2, upregulated expression of tumor necrosis factor-α, and decreased levels of AP-1 and NF-κB were also found following 30% partial liver transplantation after reperfusion.

CONCLUSION

  Liver regeneration is remarkably suppressed in SFSLT. The significant changes of intra-graft gene expression described above indicated that ischemia reperfusion injury would be severe in 30% partial liver transplantation. The capability of liver regeneration secondary to ischemia reperfusion injury might determine hepatic graft survival in SFSLT.

An experimental study of triple split-liver transplantation in dogs

AIM: To explore the feasibility of a strategy of tripartition of a whole deceased liver graft for use in 3 recipients in dogs to ultimately maximize donor organ use.

METHODS: Adult healthy mongrel dogs were selected to be donors (n = 30, weighing between 20-25 kg) and recipients (n = 30, weighing between 8-15 kg). Donor/recipient pairs were randomly matched. For donor operation, transection of the parenchymal bridge was performed between the right lateral lobe and right middle lobe, and between the left middle lobe and the quadrate lobe. After in vivo perfusion, the left, middle and right liver grafts were procured, and their primary branches were cut near the main stem. Among the three liver grafts, the one was chosen to be implanted if it's GRWR (graft-to-recipient weight ratio) was more than 1.0% and was nearest to 1.5%. Recipients entered Groups A, B and C if the left, middle and right grafts were chosen, respectively. With the piggyback technique, the outflow orifice of liver graft was anastomosed to the anterolateral wall of the recipient vena cava. The graft was revascularized via reconstructed hepatic vein and portal vein, and then the hepatic artery and bile duct were anastomosed both in an end-to-end manner. Biliary and abdominal drainage was inspected postoperatively. Autopsies were performed promptly after recipients' death to investigate the possibility of technical complications.

RESULTS: By prominent fissures, the canine liver was divided into 7 lobes, among which the parenchymal bridges were thin. The parenchymal bridge connecting the right lateral lobe to the right middle lobe was much thinner than that connecting the left middle lobe to the quadrate lobe. No major conduit was found during transection of these two parenchymal bridges. The portal vein was split into three branches. The common bile duct was formed by the union of three hepatic ducts-the left, middle and right hepatic ducts. The hepatic vein consisted of the left, median and right hepatic veins. Anatomical variations in the hepatic arteries could be found. Among three recipient groups, the operation time, anhepatic time and blood loss did not show significant differences (P > 0.05), but the mean recipient weight, liver graft weight, and GRWR differed significantly (all P < 0.01). In the three groups, none of the recipients died during surgery. Once the hepatic vein and the portal vein were anastomosed and declamped, the implanted liver regained its color soon and its appearance returned to normal following arterial revascularization. There was no statistical difference in survival duration among the three groups (128.3 h ± 48.5 h vs 102.7 h ± 59.8 h vs 98.7 h ± 46.8 h, P = 0.234). Ascites and liver necrosis were not found at autopsy. Bile was present in the bile duct and all anastomoses were patent.

CONCLUSION: Our experimental results indicate that the whole liver of a big dog can be split into three parts, every one of which can be transplanted to a small recipient as an independent allograft.

Split liver transplantation using extended right grafts: the natural history of segment 4 and its impact on early postoperative outcomes

Split liver transplantation (SLT) using extended right grafts is associated with complications related to ischemia of hepatic segment 4 (S4), and these complications are associated with poor outcomes. We retrospectively analyzed 36 SLT recipients so that we could assess the association of radiological, biological, and clinical features with S4 ischemia. The overall survival rates were 84.2%, 84.2%, and 77.7% at 1, 3, and 5 years, respectively. The recipients were mostly male (24/36 or 67%) and had a median age of 52 years (range = 13-63 years), a median body mass index of 22.9 kg/m(2) (range = 17.3-29.8 kg/m(2) ), and a median graft-to-recipient weight ratio of 1.3% (range = 0.9%-1.9%). S4-related complications were diagnosed in 22% of the patients (8/36) with a median delay of 22 days (range = 10-30 days). Secondary arterial complications were seen in 3 of these patients and led to significantly decreased graft survival in comparison with the graft survival of patients without complications (50.0% versus 85.6%, P = 0.017). Patients developing S4-related complications had significantly elevated aspartate aminotransferase (AST) levels (>1000 IU/L) on postoperative day (POD) 1 and elevated gamma-glutamyl transpeptidase (GGT) levels (>300 IU/L) on PODs 7 and 10 (P < 0.05). These AST and GGT elevations conferred a significantly high risk of developing these complications (odds ratio = 42, 95% confidence interval = 4-475, P < 0.05). The ischemic volume of S4 was extremely variable (0%-95%) and did not correlate with S4-related complications. In conclusion, our results suggest that S4-related complications are risk factors for worse graft survival, and the development of these complications can be anticipated by the early identification of a specific biological profile and a routine radiological examination.