Should we still offer split-liver transplantation for two adult recipients? A retrospective study of our experience

Current Understanding of Marginal Grafts in Liver Transplantation

End-stage liver disease (ESLD), stemming from a spectrum of chronic liver pathologies including chronic liver failure, acute cirrhosis decompensation and hepatocellular carcinoma, imposes a significant global healthcare burden. Liver transplantation (LT) remains the only treatment for ESLD. However, the escalating mortality on transplant waitlists has prompted the utilization of marginal liver grafts in LT procedures. These grafts primarily encompass elderly livers, steatotic livers, livers from donation after circulatory death, split livers and those infected with the hepatitis virus. While the expansion of the donor pool offers promise, it also introduces concomitant risks. These encompass graft failure, biliary and cardiovascular complications, the recurrence of liver disease and reduced patient and graft survival. Consequently, various established strategies, ranging from improved donor-recipient matching to surgical interventions, have emerged to mitigate these risks. This article undertakes a comprehensive assessment of the current landscape, evaluating the viability of diverse marginal liver grafts. Additionally, it synthesizes approaches aimed at enhancing the quality of such marginal liver grafts. The overarching objective is to augment the donor pool and ameliorate the risk factors associated with the shortage of liver grafts.

Improving outcomes of in situ split liver transplantation in Italy over the last 25 years

BACKGROUND & AIMS

Split liver transplant(ation) (SLT) is still considered a challenging procedure that is by no means widely accepted. We aimed to present data on 25-year trends in SLT in Italy, and to investigate if, and to what extent, outcomes have improved nationwide during this time.

METHODS

The study included all consecutive SLTs performed from May 1993 to December 2019, divided into three consecutive periods: 1993-2005, 2006-2014, and 2015-2019, which match changes in national allocation policies. Primary outcomes were patient and graft survival, and the relative impact of each study period.

RESULTS

SLT accounted for 8.9% of all liver transplants performed in Italy. A total of 1,715 in situ split liver grafts were included in the analysis: 868 left lateral segments (LLSs) and 847 extended right grafts (ERGs). A significant improvement in patient and graft survival (p <0.001) was observed with ERGs over the three periods. Predictors of graft survival were cold ischaemia time (CIT) <6 h (p = 0.009), UNOS status 2b (p <0.001), UNOS status 3 (p = 0.009), and transplant centre volumes: 25-50 cases vs. <25 cases (p = 0.003). Patient survival was significantly higher with LLS grafts in period 2 vs. period 1 (p = 0.008). No significant improvement in graft survival was seen over the three periods, where predictors of graft survival were CIT <6 h (p = 0.007), CIT <6 h vs. ≥10 h (p = 0.019), UNOS status 2b (p = 0.038), and UNOS status 3 (p = 0.009). Retransplantation was a risk factor in split liver graft recipients, with significantly worse graft and patient survival for both types of graft (p <0.001).

CONCLUSIONS

Our analysis showed Italian SLT outcomes to have improved over the last 25 years. These results could help to dispel reservations regarding the use of this procedure.

IMPACT AND IMPLICATIONS

Split liver transplant(ation) (SLT) is still considered a challenging procedure and is by no means widely accepted. This study included all consecutive in situ SLTs performed in Italy from May 1993 to December 2019. With more than 1,700 cases, it is one of the largest series, examining long-term national trends in in situ SLT since its introduction. The data presented indicate that the outcomes of SLT improved during this 25-year period. Improvements are probably due to better recipient selection, refinements in surgical technique, conservative graft-to-recipient matching, and the continuous, yet carefully managed, expansion of donor selection criteria under a strict mandatory split liver allocation policy. These results could help to dispel reservations regarding the use of this procedure.

Full-Right Full-Left Split Liver Transplantation for Two Adult Recipients: A Single-Center Experience in China

BACKGROUND

The most effective treatment for end-stage liver diseases is liver transplantation, which is impeded by the shortage of donor livers. Split liver transplantation (SLT) is important for addressing the donor liver shortage. However, full-right full-left SLT for two adult recipients is globally rarely conducted. This study aimed to investigate the clinical outcomes of this technique.

METHODS

We retrospectively analyzed the clinical data of 22 recipients who underwent full-right full-left SLT at Shulan (Hangzhou) Hospital between January, 2021 and September, 2022. The graft-to-recipient weight ratio (GRWR), cold ischemia time, operation time, length of the anhepatic phase, intraoperative blood loss, and red blood cell transfusion amount were all analyzed. The differences in liver function recovery after transplantation were compared between the left and right hemiliver groups. The postoperative complications and prognosis of the recipients were also analyzed.

RESULTS

The livers of 11 donors were transplanted into 22 adult recipients. The GRWR ranged from 1.16-1.65%, the cold ischemia time was 282.86 ± 134.87 min, the operation time was 371.32 ± 75.36 min, the anhepatic phase lasted 60.73 ± 19.00 min, the intraoperative blood loss was 759.09 ± 316.84 mL, and the red blood cell transfusion amount was 695.45 ± 393.67 mL. No significant difference in the levels of liver function markers, total bilirubin, aspartate aminotransferase, or alanine aminotransferase between left and right hemiliver groups at 1, 3, 5, 7, 14, and 28 d postoperatively was observed (both p > 0.05). One recipient developed bile leakage 10 d after transplantation, which improved with endoscopic retrograde cholangiopancreatography-guided nasobiliary drainage and stent placement. Another developed portal vein thrombosis 12 d after transplantation and underwent portal vein thrombectomy and stenting to restore portal vein blood flow. A color Doppler ultrasound performed 2 d after transplantation revealed hepatic artery thrombosis in one patient, and thrombolytic therapy was administered to restore hepatic artery blood flow. The liver function of other patients recovered quickly after transplantation.

CONCLUSIONS

Full-right full-left SLT for two adult patients is an efficient way to increase the donor pool. It is safe and feasible with careful donor and recipient selection. Transplant hospitals with highly experienced surgeons in SLT are recommended to promote using full-right full-left SLT for two adult recipients.

Biliary complications following split liver transplantation in adult recipients: a matched pair analysis on single-center experience

The utilization of split liver grafts can increase access to liver transplantation (LT) for adult patients, particularly when liver grafts are shared between 2 adult recipients. However, it is yet to be determined whether split liver transplantation (SLT) increases the risk of biliary complications (BCs) compared with whole liver transplantation (WLT) in adult recipients. This retrospective study enrolled 1441 adult patients who underwent deceased donor LT at a single-site between January 2004 and June 2018. Of those, 73 patients underwent SLTs. Graft type for SLT includes 27 right trisegment grafts, 16 left lobes, and 30 right lobes. A propensity score matching analysis selected 97 WLTs and 60 SLTs. Biliary leakage was more frequently seen in SLTs (13.3% vs. 0%; p <0.001), whereas the frequency of biliary anastomotic stricture was comparable between SLTs and WLTs (11.7% vs. 9.3%; p=0.63). Graft and patient survival rates of patients undergoing SLTs were comparable to those undergoing WLTs (p=0.42 and 0.57, respectively). In the analysis of the entire SLT cohort, BCs were seen in 15 patients (20.5%) including biliary leakage in 11 patients (15.1%) and biliary anastomotic stricture in 8 patients (11.0%) [both in 4 patients (5.5%)]. The survival rates of recipients who developed BCs were significantly inferior to those without BCs (p <0.01). By multivariate analysis, the split grafts without common bile duct increased the risk of BCs. In conclusion, SLT increases the risk of biliary leakage compared with WLT. Biliary leakage can still lead to fatal infection and thus should be managed appropriately in SLT.

Is it safe to expand the indications for split liver transplantation in adults? A single-centre analysis of 155 in-situ splits

INTRODUCTION

Split liver transplantation (SLT) enables two recipients to be transplanted using a single donor liver; typically, an adult and a child. Despite equivalent long-term outcomes to whole grafts in selected adults, the use of these grafts in high-risk adult recipients with high model for end-stage liver disease (MELD) scores (≥30), a poor pre-transplant clinical status (ICU or hospital-bound), acute liver failure or retransplantation remains controversial.

METHODS

We retrospectively analysed all deceased donor adult liver transplants performed between July 2002 and November 2019 at a single high-volume centre and performed a propensity score-matched analysis. A subgroup analysis was performed to assess utility of these grafts for high-risk recipients.

RESULTS

A total of 1090 adult liver transplants were performed, including 155 SLT (14%). Graft survival at 1-, 3- and 5-years were comparable between recipients of split and whole liver grafts (82%, 79% and 74% vs 86%, 81% and 77% respectively, log rank p = 0.537), as was patient survival at 1-, 3- and 5-years. Recipients of split grafts were more likely to have biliary complications and hepatic artery thrombosis, but equivalent long-term survival. Recipients with high MELD scores or a poor pre-transplant clinical status had similar patient and graft survival and complication profiles irrespective of whether they received split or whole grafts.

CONCLUSIONS

SLT is an important method for addressing donor shortages and provides comparable long-term outcomes in adult recipients despite an increase in short-term complications. SLT use in high-risk recipients should be considered to allow for sickest-first allocation policies. This article is protected by copyright. All rights reserved.

Full-left-full-right split liver transplantation for adult recipients: a systematic review and meta-analysis

Full-left-full-right split liver transplantation (FSLT) for adult recipients, may increase the availability of liver grafts, reduce waitlist time, and benefit recipients with below-average body weight. However, FSLT may lead to impaired graft and patient survival. This study aims to assess outcomes after FSLT. Five databases were searched to identify studies concerning FSLT. Incidences of complications, graft- and patient survival were assessed. Discrete data were pooled with random-effect models. Graft and patient survival after FSLT were compared with whole liver transplantation (WLT) according to the inverse variance method. Vascular complications were reported in 25/273 patients after FSLT (Pooled proportion: 6.9%, 95%CI: 3.1-10.7%, I² : 36%). Biliary complications were reported in 84/308 patients after FSLT (Pooled proportion: 25.6%, 95%CI: 19-32%, I² : 44%). Pooled proportions of graft and patient survival after 3 years follow-up were 72.8% (95%CI: 67.2-78.5, n = 231) and 77.3% (95%CI: 66.7-85.8, n = 331), respectively. Compared with WLT, FSLT was associated with increased graft loss (pooled HR: 2.12, 95%CI: 1.24-3.61, P = 0.006, n = 189) and patient mortality (pooled HR: 1.81, 95%CI: 1.17-2.81, P = 0.008, n = 289). FSLT was associated with high incidences of vascular and biliary complications. Nevertheless, long-term patient and graft survival appear acceptable and justify transplant benefit in selected patients.

A review of split liver transplantation with full right/left hemi-liver grafts for 2 adult recipients

Liver transplantation has become a routine operation in many transplantation centers worldwide. However, liver graft availability fails to meet patient demands. Split liver transplantation (SPLT), which divides a deceased donor liver into 2 partial liver grafts, is a promising strategy for increasing graft availability for transplantation and ameliorating organ shortage to a certain degree. However, the transplantation community has not yet reached a consensus on SPLT because of the variable results. Specifically, SPLT for 2 adult recipients using full right/left hemi-liver grafts is clinically more challenging in terms of surgical technique and potential postoperative complications. Therefore, this review summarizes the current status of SPLT, focusing on the transplantation of adult recipients. Furthermore, the initiation of the SPLT program, donor allocation, surgical aspects, recipient outcomes, and obstacles to developing this procedure will be thoroughly discussed. This information might help provide an optimal strategy for implementing SPLT for 2 adult recipients among current transplantation societies. Meanwhile, potential obstacles to SPLT might be overcome in the near future with growing knowledge, experience, and refinement of surgical techniques. Ultimately, the widespread diffusion of SPLT may increase graft availability and mitigate organ donation shortages.

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.

Is there an ethical obligation to split every donor liver? Scarce resources, medical factors, and ethical reasoning

SLT has the potential to counter the worldwide shortage of donor organs. Although the preferred recipients of SLT are usually pediatric patients, a more stringent ethical argument than the fundamental prioritization of children is to demonstrate that SLT of deceased donor organs could increase access to this potentially lifesaving resource for all patients, including children. Several empirical studies show that SLT also makes it possible to achieve similar outcomes to WLT in adults if several factors are observed. In general, it can be regarded as ethically permissible to insist on splitting a donor liver if, in an individual case, SLT is expected to have a similar outcome to that of WLT. The question is therefore no longer whether, but under what conditions SLT is able to achieve similar results to WLT. One of the main challenges of the current debate is the restricted comparability of the available data. We therefore have an ethical obligation to improve the available empirical data by implementing prospective clinical studies, SLT programs, and national registries. The introduction of 2 modes of allocation-one for patients willing to accept both SLT and WLT, and a second for patients only willing to accept WLT-would help to resolve the issue of patient autonomy in the case of mandatory splitting policy.

A national mandatory-split liver policy: A report from the Italian experience

To implement split liver transplantation (SLT) a mandatory-split policy has been adopted in Italy since August 2015: donors aged 18-50 years at standard risk are offered for SLT, resulting in a left-lateral segment (LLS) graft for children and an extended-right graft (ERG) for adults. We aim to analyze the impact of the new mandatory-split policy on liver transplantation (LT)-waiting list and SLT outcomes, compared to old allocation policy. Between August 2015 and December 2016 out of 413 potentially "splittable" donors, 252 (61%) were proposed for SLT, of whom 53 (21%) donors were accepted for SLT whereas 101 (40.1%) were excluded because of donor characteristics and 98 (38.9%) for absence of suitable pediatric recipients. The SLT rate augmented from 6% to 8.4%. Children undergoing SLT increased from 49.3% to 65.8% (P = .009) and the pediatric LT-waiting list time dropped (229 [10-2121] vs 80 [12-2503] days [P = .045]). The pediatric (4.5% vs 2.5% [P = .398]) and adult (9.7% to 5.2% [P < .001]) LT-waiting list mortality reduced; SLT outcomes remained stable. Retransplantation (HR = 2.641, P = .035) and recipient weight >20 kg (HR = 5.113, P = .048) in LLS, and ischemic time >8 hours (HR = 2.475, P = .048) in ERG were identified as predictors of graft failure. A national mandatory-split policy maximizes the SLT donor resources, whose selection criteria can be safely expanded, providing favorable impact on the pediatric LT-waiting list and priority for adult sick LT candidates.

In Situ Splitting of the Cadaver Liver for Two Adult Recipients by LDLT Technique

BACKGROUND

To expand the donor pool, split liver transplantation is conventionally performed for one adult and one pediatric recipient. Application of this technique for two adult recipients can produce remarkable impact on the waiting list. Proper donor and recipient selection is crucial for the favorable outcome following full-right and full-left liver split. Right lobe adult to adult living donor liver transplantation (LDLT) is essentially a full right and full left split. However, LDLT techniques have not been used for full right and left split.

METHODS

We performed in situ splitting of the whole liver using LDLT techniques from a hemodynamically stable young deceased donor and transplanted into two adult recipients, both with model for end-stage liver disease score of 17. The transection was carried out through the midplane of liver, generating a right lobe and a left lobe graft.

RESULTS

Both the recipients had uneventful postoperative recovery. At ten months of follow up, both the recipients are doing well with good liver function.

CONCLUSION

Based on the concept of living related liver transplantation, our case explores the technical feasibility of full-right and full-left in situ liver split.

In Situ Split Liver Transplantation for 2 Adult Recipients: A Single-Center Experience

Background Material and Methods Results Conclusions.

Using on-site liver 3-D reconstruction and volumetric calculations in split liver transplantation

BACKGROUND

Split liver transplantation increases the number of grafts available for transplantation. Pre-recovery assessment of liver graft volume is essential for selecting suitable recipients. The purpose of this study was to determine the ability and feasibility of constructing a 3-D model to aid in surgical planning and to predict graft weight prior to an in situ division of the donor liver.

METHODS

Over 11 months, 3-D volumetric reconstruction of 4 deceased donors was performed using Pathfinder Scout© liver volumetric software. Demographic, laboratory, operative, perioperative and survival data for these patients along with donor demographic data were collected prospectively and analyzed retrospectively.

RESULTS

The average predicted weight of the grafts from the adult donors obtained from an in situ split procedure were 1130 g (930-1458 g) for the extended right lobe donors and 312 g (222-396 g) for left lateral segment grafts. Actual adult graft weight was 92% of the predicted weight for both the extended right grafts and the left lateral segment grafts. The predicted and actual graft weights for the pediatric donors were 176 g and 210 g for the left lateral segment grafts and 308 g and 280 g for the extended right lobe grafts, respectively. All grafts were transplanted except for the right lobe from the pediatric donors due to the small graft weight.

CONCLUSIONS

On-site volumetric assessment of donors provides useful information for the planning of an in situ split and for selection of recipients. This information may expand the donor pool to recipients previously felt to be unsuitable due to donor and/or recipient weight.

Current status and perspectives in split liver transplantation

Growing experience with the liver splitting technique and favorable results equivalent to those of whole liver transplant have led to wider application of split liver transplantation (SLT) for adult and pediatric recipients in the last decade. Conversely, SLT for two adult recipients remains a challenging surgical procedure and outcomes have yet to improve. Differences in organ shortages together with religious and ethical issues related to cadaveric organ donation have had an impact on the worldwide distribution of SLT. Despite technical refinements and a better understanding of the complex liver anatomy, SLT remains a technically and logistically demanding surgical procedure. This article reviews the surgical and clinical advances in this field of liver transplantation focusing on the role of SLT and the issues that may lead a further expansion of this complex surgical procedure.

Split-liver full-left full-right: proposal for an operative protocol

INTRODUCTION

Worldwide, organ shortage is a major limiting factor to transplantations. One possible way to face graft scarcity is splitting full livers into hemilivers; this procedure would allow transplantation in 2 adult recipients with the use of a single organ from a deceased donor.

OBJECTIVE

The goal of this study was to describe an adult-to-adult split liver operative protocol and share it between centers interested in exploring this procedure.

MATERIALS AND METHODS

A literature review was first conducted to elaborate on the present protocol; second, selection criteria for suitable deceased donors were identified. The technical aspects of performing the procurement were also analyzed; finally, the recipient selection criteria and the transplantation criteria were determined.

RESULTS

The donor characteristics should be consistent with the following: age≤55 years; weight≥70 kg; body mass index<28 kg/m2; intensive care unit stay<7 days; sodium level<160 mEq/L if the intensive care unit stay is >2 days; maximum transaminase value 3 times normal; hemodynamic stability; negative for hepatitis B surface antigen, hepatitis C virus, and human immunodeficiency virus; macrosteatosis<20%; macroscopic adequacy; and absence of anatomic anomalies requiring complex reconstruction. The procurement hospital should provide the preoperative computed tomography scan, liver dissector, and the intraoperative ultrasound. Indication for in situ or ex situ splitting depends on the hepatic vein outflow anatomy. Graft-to-recipient weight ratio should be ≥1%, and the graft-to-recipient spleen size ratio should be ≥0.6. United Network for Organ Sharing status 1 and 2A recipients are excluded, as are patients with transjugular intrahepatic portosystemic shunts. Hemiliver transplants are performed as in living-donor liver transplantation, and portal hyperflow is corrected by splenic artery ligation, splenectomy, and portal infusion of vasoactive drugs.

CONCLUSIONS

The present protocol was proposed to test the validity of the full-left full-right split liver procedure. A retrospective analysis found that 130 transplantations were suitable for this procedure according to the present protocol in the period January 1, 2008, through December 31, 2011 (65 donors). We believe that these numbers could be greatly increased once this procedure is proven feasible and safe within the proposed criteria.

Split liver transplantation: What’s unique?

The intraoperative management of split liver transplantation (SLT) has some unique features as compared to routine whole liver transplantations. Only the liver has this special ability to regenerate that confers benefits in survival and quality of life for two instead of one by splitting livers. Primary graft dysfunction may result from small for size syndrome. Graft weight to recipient body weight ratio is significant for both trisegmental and hemiliver grafts. Intraoperative surgical techniques aim to reduce portal hyperperfusion and decrease venous portal pressure. Ischemic preconditioning can be instituted to protect against ischemic reperfusion injury which impacts graft regeneration. Advancement of the technique of SLT is essential as use of split cadaveric grafts expands the donor pool and potentially has an excellent future.

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.

Split liver transplantation using Hemiliver graft in the MELD era: a single center experience in the United States

Under the "sickest first" Model for End-Stage Liver Disease (MELD) allocation, livers amenable to splitting are most often allocated to patients unsuitable for split liver transplantation (SLT). Our experience with SLT using hemilivers was reviewed. From April 2004 to June 2012, we used 25 lobar grafts (10 left lobes and 15 right lobes) for adult-sized recipients. Twelve recipients were transplanted with primary offers, and 13 were transplanted with leftover grafts. Six grafts were shared with other centers. The data were compared with matched whole liver grafts (n = 121). In 92% of donors, the livers were split in situ. Hemiliver recipients with severe portal hypertension had a greater graft-to-recipient weight ratio than those without severe portal hypertension (1.96% vs. 1.40%, p < 0.05). Hemiliver recipients experienced biliary complications more frequently (32.0% vs. 10.7%, p = 0.01); however, the 5-year graft survival for hemilivers was comparable to whole livers (80.0% vs. 81.5%, p = 0.43). The secondary recipients with leftover grafts did not have increased incidences of graft failure (p = 0.99) or surgical complications (p = 0.43) compared to the primary recipients. In conclusion, while routine application is still controversial due to various challenges, hemiliver SLT can achieve excellent outcomes under the MELD allocation.

Feasibility of split liver transplantation for 2 adults in the model of end-stage liver disease era

OBJECTIVE

To examine the results of split liver transplantation for 2 adults in the model of end-stage liver disease (MELD) era.

BACKGROUND

In the MELD era, liver allografts are first allocated to recipients with the highest MELD scores. However, the application of split liver transplantation for 2 adults in urgent condition has doubled and has become a matter of concern.

METHODS

Twenty-one deceased liver grafts were split into full right and full left lobes for 42 adult recipients. One of the hemiliver grafts was allocated to the recipient with the highest MELD score in the waiting list. The results of split liver transplantation were examined and compared with those of living donor liver transplantation.

RESULTS

Among 42 recipients, 24 (57.1%) had MELD scores higher than 20. The median (interquartile) MELD score for the recipients with split liver transplantation was 22 (15-30), which was higher than that for the recipients with living donor liver transplantation (P < 0.001). The 1-, 3-, and 5-year survival rates for split liver transplantation were comparable with those of living donor transplantation (P = 0.489). Nevertheless, 10 of 42 split liver recipients died within 3 months after transplantation. By receiver operating characteristic curve analysis, the safe graft-recipient weight ratio was better more than 1% to avoid early patient death for split liver transplantation.

CONCLUSIONS

Although most of the recipients with split liver transplantation had high MELD scores, the results were comparable with those of living donor liver transplantation. Split liver transplantation for 2 adults is still feasible in the MELD era.

Adult left liver transplantation from split livers and living donors: a 14-year single-center experience

BACKGROUND

In an era of organ scarcity, the use of left liver grafts for adult recipients could increase the access to liver transplantation (LT). The aim of this study was to evaluate the results in a single-center series of adult left LT over a 14-yr period.

PATIENTS AND METHODS

Between March 1996 and March 2010, 30 adult patients underwent LT with a left liver obtained from 16 split cadaveric livers and 14 living donors (LD). Portal vein inflow modulation was performed in selected cases.

RESULTS

A total of 19 (63.3%) grafts had early dysfunction leading to graft failure in six cases (20%). One third of the grafts developed small-for-size syndrome (SFSS). One-yr patient and graft survival was 80% and 76.7%, respectively. Regarding two successive periods, one-yr patient and graft survival dramatically increased from 62.5% to 100% (p = 0.01) and 56.2% to 100% (p = 0.002), respectively. Multivariate analysis disclosed that completion of a portosystemic shunt and the occurrence of post-operative ascites were significantly associated with graft failure.

CONCLUSIONS

Our results support that improved surgical techniques and careful patient selection can lead to a safe use of left livers for transplantation in adult recipients. Inflow modulation could be performed in very selected cases.

[Small-for-size: experimental findings for liver surgery]

The characteristics of the hepatic macrocirculation, i.e., the parallel portal-venous and arterial blood supply, is of utmost relevance for liver surgery. With extended hepatectomy or transplantation of a reduced-size liver the remaining or transplanted liver tissue is overperfused because the liver fails to regulate the portal-venous inflow. This portal hyperperfusion is responsible for the initiation of liver cell proliferation but represents at the same time one of the substantial events in the pathogenesis of the small-for-size syndrome. Portal-venous hyperperfusion, the so-called hepatic arterial buffer response, which describes the semi-reciprocal relationship between the portal-venous and hepatic arterial blood flows, leads to an arterial hypoperfusion of the small-for-size liver. In this article experimental and clinical data are discussed which underline the high but so far overseen relevance of this arterial underperfusion in the development of a small-for-size syndrome.

Full-right-full-left split liver transplantation: the retrospective analysis of an early multicenter experience including graft sharing

Full-right-full-left split liver transplantation divides a donor liver into two grafts to be transplanted in adult-size patients. Major technical and organizational difficulties have limited its application to few single center series. We retrospectively analyzed the long-term results of the first multicenter series of this procedure with graft sharing. Between November 1998 and January 2005, 43 transplants were performed by five centers from 23 full-right-full-left in situ split liver procedures; 65% of the grafts were shared. A total of 31 (72%) patients had complications above grade II; 3 (6.9%) were retransplanted. Hospital mortality was 23% with sepsis as the main cause. Six patients died in the long term, two of them for a road accident. A total of 27 patients are alive after a median follow-up of 3200 days (2035-4256). Actuarial survival at 1 and 10 years were 72.1%, 62.6% and 65.1%, 57.9%, respectively for patients and grafts. These figures are similar to those reported for adult living donor liver transplantation by the European Registry over a similar period. Multicenter collaboration in sharing of these grafts is feasible and can help facing the organizational limits, thus increasing diffusion of full-right-full-left split liver transplantation.

Split liver transplantation: an overview

Liver transplantation (OLT) has become the only treatment modality for patients with end-stage liver diseases. Establishment of standard liver transplantation technique, development of better immunosuppressive medications and accumulated experience using them safely, and improvement of intensive care and anesthesia played major role to have current 88%-90% 1-year survival after liver transplantation. As liver transplantations became more successful with the growing experience and development in the field, the increased demand for liver allografts could not match the available supply of donor organs. As a result of this imbalance, each year nearly 3000 patients die in the United States awaiting liver transplantation on the national waiting list. Split liver transplantation (SLT) has been perceived as an important strategy to increase the supply of liver grafts by creating 2 transplants from 1 allograft. The bipartition of a whole liver also carries utmost importance by increasing the available grafts for the pediatric patients, where size-matched whole liver allografts are scarce, leading increased incidence of waiting list mortality in this group. In the common approach of the split liver procedure, liver is divided into a left lateral segment graft (LLS) to be transplanted to a child and a right extended liver lobe graft for an adult recipient. In a technically more challenging variant of this procedure, the principle is to split the liver into 2 hemigrafts and use the left side for a small adult or a teenager and the right for a medium-sized adult patient. Donor selection for splitting, technical expertise in both OLT and hepatobiliary surgery, logistics to decrease total ischemia time, and manpower of the transplantation team are important factors for successful outcomes after SLT. The liver can be split on the back table (ex situ) or in the donor hospital before the donor cross-clamp using in situ splitting technique, which was developed directly from living donor liver transplantation. The most important advantage of in situ splitting is to decrease the total ischemia time and increased the possibility of inter-center sharing. The in situ technique of splitting has other advantages, including evaluation of the viability of segment IV in case of LLS splitting and better control of bleeding from cut surface upon reperfusion on the recipient. Recipient selection for split liver grafts is also crucial for success after SLT. In this review, we aim to summarize the advances that have occurred in SLT. We also discuss anatomic and technical aspects, including both approaches to SLT, which is now considered by many centers to be a routine operation.

Regulation of hepatic blood flow: The hepatic arterial buffer response revisited

The interest in the liver dates back to ancient times when it was considered to be the seat of life processes. The liver is indeed essential to life, not only due to its complex functions in biosynthesis, metabolism and clearance, but also its dramatic role as the blood volume reservoir. Among parenchymal organs, blood flow to the liver is unique due to the dual supply from the portal vein and the hepatic artery. Knowledge of the mutual communication of both the hepatic artery and the portal vein is essential to understand hepatic physiology and pathophysiology. To distinguish the individual importance of each of these inflows in normal and abnormal states is still a challenging task and the subject of ongoing research. A central mechanism that controls and allows constancy of hepatic blood flow is the hepatic arterial buffer response. The current paper reviews the relevance of this intimate hepatic blood flow regulatory system in health and disease. We exclusively focus on the endogenous interrelationship between the hepatic arterial and portal venous inflow circuits in liver resection and transplantation, as well as inflammatory and chronic liver diseases. We do not consider the hepatic microvascular anatomy, as this has been the subject of another recent review.

Progress in surgical techniques in pediatric liver transplantation

Pediatric LT has evolved into an accepted treatment modality for children with end-stage liver disease with excellent long-term graft and patient survival. A number of factors have been critical in the improvement in recipient outcomes including a change in organ donation from donation after cardiac death, to donation after brain death, and more recently live donor LT and a better appreciation of hepatic anatomy allowing for split LT, LDLT, auxiliary partial orthotopic LT, and laparoscopic donor hepatectomy. In this review we summarize the surgical advances that have occurred in pediatric LT that have been important in shaping what is now considered by many to be a routine operation.

Conventional split liver transplantation for two adult recipients: a recent experience in a single European center

BACKGROUND

Split liver transplantation (SLT) for two adult recipients is still considered a challenging procedure, especially when subjected to model for end-stage liver disease (MELD)-based allocation criteria.

METHODS

Twenty-two SLTs were performed in adult recipients in a European center operating within a MELD-oriented system. Thirteen right-sided grafts and nine left-sided grafts were used. Right-sided grafts included 11 extended right grafts and two full right grafts. Left-sided grafts included six left lateral segment grafts and three full left grafts. Ninety-three percent of donors were allocated based on MELD score. Median graft-to-recipient body weight ratio was 1.53 (range 1.07-2.11) with right-sided grafts and 0.81 (range 0.67-1.11) with left-sided grafts. Liver cirrhosis (46%) and metabolic/genetic disorders (56%) were the main indications for transplant in recipients of right and left grafts, respectively.

RESULTS

Overall patient and graft survival were 90% and 86%. Patient survival was 84% in recipients of right grafts and 100% in recipients of left grafts. Graft survival was 84% and 89%, respectively. Vascular and biliary complications occurred in 14% and 4% of cases. Postoperative serum levels of total bilirubin were significantly higher in recipients of left-sided grafts versus right-sided grafts on postoperative days 7 and 14. Prothrombin activity was significantly lower in recipients of left-sided grafts versus right-sided grafts on postoperative days 3 and 7.

CONCLUSIONS

SLT for two adult recipients can be successfully performed even using left lateral segments by assigning one graft according to MELD score, and with a more liberal allocation of the second graft.

[How can the number of liver transplantations be increased?]

The number of patients suitable for liver transplantation is progressively increasing due to the excellent results achieved with this procedure, giving rise to a growing imbalance in the number of candidates on the waiting list and the number of donors. This situation has prompted transplant teams to search for alternatives to increase the number of liver grafts. On the one hand, the criteria for donation have been broadened to include donors with advanced age, liver steatosis, hepatitis B and C viruses, neoplasms, and benign underlying diseases. On the other hand, new transplant techniques have been used with grafts from split livers, living donors, sequential or domino transplants and non-heart-beating donors. Other options such as xenotransplantation and hepatocyte transplants currently lack clinical applicability.