Technical refinements and results in full-right full-left splitting of the deceased donor liver

Normothermic Liver Machine Perfusion and Successful Transplantation of Split Liver Grafts: From Proof of Concept to Clinical Implementation

BACKGROUND

Normothermic liver machine perfusion (NLMP) is advancing the field of liver transplantation (LT). Beyond improved preservation and organ assessment, NLMP helps to increase organ utilization. We herein address the feasibility and merit of NLMP in split liver transplantation (SLT) to postpone the transplantation of the second split graft to the following day.

METHODS

We analyzed the perfusion characteristics and outcomes of all consecutive adult recipients who underwent SLT following NLMP from February 1, 2018, to June 30, 2023. The primary endpoint was 90-d graft and patient survival. Secondary endpoints were posttransplant complications and 90-d morbidity.

RESULTS

Three right and 3 extended right SLT following NLMP have been performed. NLMP was uneventful in all cases. Perfusion characteristics differed according to graft volume. Mean perfusion time was 17:00 h (±05:13) and bile production ranged between 8 and 21 mL/h. All split grafts fulfilled predefined center viability criteria during NLMP and were transplanted on the following day. The 90-d graft and patient survival rate was 100%. Three patients (50%) required an early relaparotomy, and 2 patients (33.3%) developed biliary complications. The 90-d morbidity as recorded by the comprehensive complication index was 62.7 (±24.7).

CONCLUSIONS

NLMP of split liver grafts is technically feasible and safe. Through prolongation of preservation time, NLMP allows to safely postpone transplantation of the second split liver graft to the next day.

Full-left/Full-right Liver Splitting With Middle Hepatic Vein and Caval Partition During Dual Hypothermic Oxygenated Machine Perfusion

BACKGROUND

Split liver transplantation is a valuable means of mitigating organ scarcity but requires significant surgical and logistical effort. Ex vivo splitting is associated with prolonged cold ischemia, with potentially negative effects on organ viability. Machine perfusion can mitigate the effects of ischemia-reperfusion injury by restoring cellular energy and improving outcomes.

METHODS

We describe a novel technique of full-left/full-right liver splitting, with splitting and reconstruction of the vena cava and middle hepatic vein, with dual arterial and portal hypothermic oxygenated machine perfusion. The accompanying video depicts the main surgical passages, notably the splitting of the vena cava and middle hepatic vein, the parenchymal transection, and the venous reconstruction.

RESULTS

The left graft was allocated to a pediatric patient having methylmalonic aciduria, whereas the right graft was allocated to an adult patient affected by hepatocellular carcinoma and cirrhosis.

CONCLUSIONS

This technique allows ex situ splitting, counterbalancing prolonged ischemia with the positive effects of hypothermic oxygenated machine perfusion on graft viability. The venous outflow is preserved, safeguarding both grafts from venous congestion; all reconstructions can be performed ex situ, minimizing warm ischemia. Moreover, there is no need for highly skilled surgeons to reach the donor hospital, thereby simplifying logistical aspects.

Quantifying the Disadvantage of Small Recipient Size on the Liver Transplantation Waitlist, a Longitudinal Analysis Within the Eurotransplant Region

BACKGROUND

Small adult patients with end-stage liver disease waitlisted for liver transplantation may face a shortage of size-matched liver grafts. This may result in longer waiting times, increased waitlist removal, and waitlist mortality. This study aims to assess access to transplantation in transplant candidates with below-average bodyweight throughout the Eurotransplant region.

METHODS

Patients above 16 y of age listed for liver transplantation between 2010 and 2015 within the Eurotransplant region were eligible for inclusion. The effect of bodyweight on chances of receiving a liver graft was studied in a Cox model corrected for lab-Model for End-stage Liver Disease (MELD) score updates fitted as time-dependent variable, blood type, listing for malignant disease, and age. A natural spline with 3 degrees of freedom was used for bodyweight and lab-MELD score to correct for nonlinear effects.

RESULTS

At the end of follow-up, the percentage of transplanted, delisted, and deceased waitlisted patients was 49.1%, 17.9%, and 24.3% for patients with a bodyweight <60 kg (n = 1267) versus 60.1%, 15.1%, and 18.6% for patients with a bodyweight ≥60 kg (n = 10 520). To reach comparable chances for transplantation, 60-kg and 50-kg transplant candidates are estimated to need, respectively, up to 2.8 and 4.0 more lab-MELD points than 80-kg transplant candidates.

CONCLUSIONS

Decreasing bodyweight was significantly associated with decreased chances to receive a liver graft. This resulted in substantially longer waiting times, higher delisting rates, and higher waitlist mortality for patients with a bodyweight <60 kg.

Transplant oncology - Current indications and strategies to advance the field

Liver transplantation (LT) was originally described by Starzl as a promising strategy to treat primary malignancies of the liver. Confronted with high recurrence rates, indications drifted towards non-oncologic liver diseases with LT finally evolving from a high-risk surgery to an almost routine surgical procedure. Continuously improving outcomes following LT and evolving oncological treatment strategies have driven renewed interest in transplant oncology. This is not only reflected by constant refinements to the criteria for LT in patients with HCC, but especially by efforts to expand indications to other primary and secondary liver malignancies. With new patient-centred oncological treatments on the rise and new technologies to expand the donor pool, the field has the chance to come full circle. In this review, we focus on the concept of transplant oncology, current indications, as well as technical and ethical aspects in the context of donor organs as precious resources.

Revisiting the forgotten "full-right full-left" liver division: Simplified technique and new strategical considerations for clinical implementation in Italy

BACKGROUND

Full-right/full-left liver splitting was introduced early in the 90s as part of the great wave of technical innovations that characterized that decade. One approach was to divide the liver on the right of the Cantlie's line and leave the middle hepatic vein with the left graft, with both grafts allocated to adults. Both grafts had some functional disadvantages and exposed the adult recipients to some early hepatic dysfunction, and the results were not great. An alternative approach consisted of an ex situ division of the liver, exactly along Cantlie's line, thus sharing the middle hepatic vein between the two grafts. None of these two techniques were really adopted, and there has been nearly no transplantation of this type in the last decade worldwide.

METHOD AND RESULTS

The authors propose a variation of the latter technique that was used recently with success: The division of the liver is made simpler; the two grafts are prepared ex situ and need a simple vascular reconstruction (one venous patch on each graft); and the grafts can be implanted using very standard techniques.

CONCLUSION

Because candidates for liver transplantation weighing 25-60 kg (old children, teenagers, and some small adults) are often at some disadvantage in getting size-matched livers (this range of weight is less represented in the donor population), implementing the latter technique would help provide adequate grafts for them. In Italy, where many livers offered for splitting are not used, there would be ample room for implementing this option within the actual donor pool and allocation system.

Liver transplantation for colorectal secondaries: on the way to validation

PURPOSE OF REVIEW

Liver transplantation for nonresectable colorectal liver metastases (CRLMs) is an emerging field within transplant oncology. This review summarizes recent developments within this field.

RECENT FINDINGS

More stringent selection criteria can yield 5-year survival rates that are similar to conventional indications for liver transplantation. Response to chemotherapy, low carcinoembryonic antigen levels, limited tumor volume and stable disease with observation time exceeding 12 months are fundamental requirements in this context. Radiomic analysis of pre transplant PET/computed tomography scans to determine metabolic tumor volume (MTV) in the liver seems particularly promising with regards to prediction of a favorable tumor biology. MTV values below 70 cm3 are associated with excellent long-term survival after transplantation, whereas the MTV threshold for liver resection seem far smaller. Recent studies put into question whether technical nonresectability per se is a valid inclusion criterion for liver transplantation. In patients with high hepatic tumor burden, but otherwise favorable prognostic features as assessed by the Oslo score, liver transplantation could possibly give a clinically relevant survival benefit compared with liver resection.

SUMMARY

Liver transplantation is feasible treatment option in highly selected patients with nonresectable CRLMs. Robust and stringent selection criteria should be applied according to international consensus guidelines.

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.

Feasibility of Full-Right/Full-Left Split-Liver Transplant in Pediatric Deceased Donors for Pediatric Recipients

This case report describes the first ex situ full-right/full-left splitting of a liver from a pediatric deceased donor in the Middle East with an excellent outcome for both recipients. The left lateral split-liver transplant requires division of the deceased donor liver into a left lateral lobe for a pediatric recipient and an extended right lobe for an adult recipient, thus producing only 1 graft for a pediatric recipient. Full-right/full-left liver transplant, which splits the liver along the line of Cantlie, is a much more complex and challenging surgery, even though the technique is fully developed, and is theoretically able to produce 2 sizeable grafts for 2 pediatric recipients. However, the full-right/full-left liver transplant remains limited because of the small vascular structures and therefore was not recommended and was not previously described in the literature.

Encouraging Split Liver Transplantation for Two Adult Recipients to Mitigate the High Incidence of Wait-list Mortality in The Setting of Extreme Shortage of Deceased Donors

Background: Organ demand for liver transplantation (LT) is constantly increasing. Split liver transplantation (SPLT) is an ideal option for increasing the number of available liver grafts for transplantation and ameliorating organ shortage to a certain degree. However, SPLT for two adult recipients is still not broadly applied. Methods: We retrospectively analyzed the outcomes of SPLT for adult recipients at a single center. All donor, recipient, and transplantation factors were thoroughly investigated to clarify factors affecting patient outcomes after LT. Results: One hundred consecutive adult SPLTs were performed during the study period. Early mortality and 1-year mortality occurred in 21 and 31 recipients, respectively. On multivariate analysis, graft weight (p = 0.036, odds ratio = 0.99, 95% confidence interval = 0.98–0.99) was the independent risk factor associated with early mortality; however, no factor was significantly related to 1-year mortality. On receiver operating characteristic curve analysis, a graft weight of 580 g was identified the cutoff for stratifying outcomes. Recipients transplanted with a graft weighing ≥580 g had significantly better outcome as compared with other recipients (p = 0.001). Moreover, SPLT remarkably provided a better survival benefit for recipients than those on the LT wait-list (p < 0.0001). Conclusions: Given the considerable incidence of wait-list mortality, SPLT for two adult recipients should be encouraged whenever possible to increase the donor pool and benefit patients awaiting LT. Nonetheless, caution should be taken with a smaller graft weight owing to the risk of early graft loss.

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.

Split liver technique with middle hepatic vein reconstruction on livers from transplant hepatectomies: a useful tool for surgical improvement

Livers removed during transplant hepatectomies could represent a useful anatomic ex vivo resource for surgical training, since they are intact and not altered by post-mortem changes yet. The aim of this study is to investigate the effectiveness of such kind of surgical training applied on some hepatic surgery techniques. In the present paper, we focused on split liver operation and middle hepatic vein (MHV) bipartition/reconstruction, since these procedures have a quite long learning curve. Seven native livers were submitted to split liver procedure by a senior resident assisted by a fully trained hepatic surgeon. Pre-splitting ultrasound mapping was compared to pre-operative CT scan. The whole graft was divided into two hemi-livers and the MHV into two hemi-confluents and reconstructed by venous or arterial patches obtained by deceased donor iliac homograft. Water tightness of the anastomosis was confirmed by hydro-pneumatic test and bench portal perfusion. Reduction in operating time was considered an indirect indicator of surgical skill improvement. In all cases, the US confirmed the anatomical distribution of MHV tributaries observed by pre-transplant CT scan. The "ex situ" splitting procedures and MHV bipartition and reconstruction were performed in all native livers in the usual time required for liver transplantation bench surgery (range 50-75 min). Liver grafts removed during hepatectomy could represent a useful resource of intact organs to perform surgical training and boost surgical confidence. In our initial experience, the study of venous drainage of the MHV and application of liver splitting technique and MHV reconstruction resulted technically feasible.

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.

Outcomes of Full-Right-Full-Left Split Liver Transplantation in Adults in the USA: A Propensity-Score Matched Analysis

BACKGROUND

Splitting a liver for utilization in adult/pediatric recipients has been shown to decrease mortality on the wait list without increasing the overall risk of long-term graft failure compared to a whole graft. However, splitting a single donor organ for two adult recipients, full-right-full-left split liver transplantation (FRFLSLT), to overcome organ shortage is still considered controversial.

OBJECTIVE

This study assessed the outcome of FRFLSLT comparing full-right (FR) and full-left (FL) with whole liver (WL) allografts in adults (1998-2010) using UNOS standard transplant analysis and research (STAR) file. Methods: Unadjusted allograft and patient survival were estimated using Kaplan-Meier survival curves. Adjusted analyses of survival were conducted controlling for propensity for WL allograft.

RESULTS

There were 83,313 cases of WL, 651 FR and 117 FL. Significant differences were evident in the unadjusted cohort between recipients who received FR and FL including donor, cold ischemic time, and days on transplant waiting list. Use of FL allograft resulted in a trend toward lower graft and patient survival compared to WL and FR, which was not statistically significant (p=0.07). In the matched cohort, FL hemiliver allograft had no detrimental effect on the allograft or patient survival after split liver transplantation when compared to FR and WL.

CONCLUSION

After adjusting for donor and recipient characteristics, there was no difference in allograft or patient survival with the use of FL, FR, or WL after liver transplantation in adults. FRFLSLT is a valuable and safe option to expand the donor pool.

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.

Right lobe split liver transplantation versus whole liver transplantation in adult recipients: A systematic review and meta-analysis

Split liver transplantation (SLT) has proven to be an effective technique to reduce the mortality of children on the waiting list, but whether creating 2 split grafts from 1 standard-criteria whole liver would compromise outcomes of adult recipients remains uncertain. We conducted this meta-analysis to compare outcomes of right lobe SLT and whole liver transplantation (WLT) in adult patients. PubMed, Embase, and the Cochrane Library were searched for relevant articles published before December 2014. Outcomes assessed were patient survival (PS), graft survival (GS), and major surgical complications after transplantation. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to synthesize the results. Seventeen studies with a total of 48,457 patients met the full inclusion criteria. PS and GS rates were all found to be equivalent between SLT and WLT recipients. However, SLT was associated with higher rates of overall biliary complications (OR = 1.66; 95% CI = 1.29-2.15; P < 0.001), bile leaks (OR = 4.30; 95% CI = 2.97-6.23; P < 0.001), overall vascular complications (OR = 1.81; 95% CI = 1.29-2.53; P < 0.001), hepatic artery thromboses (OR = 1.71; 95% CI = 1.17-2.50; P = 0.005), and outflow tract obstructions (OR = 4.17; 95% CI = 1.75-9.94; P = 0.001). No significant difference was observed in incidences of biliary stricture, portal vein complications, postoperative bleeding requiring surgical treatments, primary nonfunction, and retransplantations. In subgroup analyses, biliary and vascular complications only increased after ex vivo SLT rather than in situ SLT, and SLT recipients had more retransplantations if they matched with WLT recipients in terms of urgent status. In conclusion, adult right lobe SLT was associated with increased biliary and vascular complications compared with WLT, but it did not show significant inferiority in PSs and GSs.

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.

Advances in the management of the explanted donor liver

Liver transplantation is the best therapy in end-stage liver disease. Donor organ shortage and efforts to expand the donor organ pool are permanent issues given that advances in perioperative management and immunosuppressive therapy have brought the procedure into widespread clinical use. The management of organ procurement, including donor preconditioning and adequate organ storage, has a key role in transplantation. However, the organ procurement process can differ substantially between transplant centres, depending on local and national preferences. Advances in the field have come from experimental and clinical research on dynamic storage systems, such as machine perfusion devices, as an alternative to static cold storage. Determination of the clinical significance of these new systems is a topic worthy of future investigations.

A prospective policy development to increase split-liver transplantation for 2 adult recipients: results of a 12-year multicenter collaborative study

OBJECTIVE

To analyze in a multicenter study the potential benefit of a new prospective policy development to increase split-liver procedures for 2 adult recipients.

BACKGROUND

Split-liver transplantation is an important means of overcoming organ shortages. Division of the donor liver for 1 adult and 1 pediatric recipient has reduced the mortality of children waiting for liver transplantation but the benefits or disadvantages to survival when the liver is divided for 2 adults (adult-to-adult split-liver transplant, AASLT) compared with recipients of a whole graft have not been fully investigated.

METHODS

We developed a computerized algorithm in selected donors for 2 adult recipients and applied it prospectively over a 12-year period among 7 collaborative centers. Patient and graft outcomes of this cohort receiving AASLT either as full right grafts or full left grafts were analyzed and retrospectively compared with a matched cohort of adults who received a conventional whole-liver transplant (WLT). Univariate and multivariate analysis was done for selected clinical variables in the AASLT group to assess the impact on the patient outcome.

RESULTS

Sixty-four patients who received the AASLT had a high postoperative complication rate (64.1% grade III and IV) and a lower 5-year survival rate than recipients of a WLT (63.3% and 83.1%)

CONCLUSIONS

AASLT should be considered a surgical option for selected smaller-sized adults only in experimental clinical studies in experienced centers.

Ex vivo split-liver transplantation: the true right/left split

BACKGROUND

Successful left lateral segment (sectionectomy) and right trisegmentectomy (trisectionectomy) split-liver transplantation (SLT) have been achieved. However, there are few reports of the use of true right/left splitting in SLT.

METHODS

A single-centre retrospective review of true right/left ex vivo split-liver transplants performed during the period 1993-2010 was conducted. Nine cadaveric liver grafts underwent splitting and the resultant 18 allografts were used in transplants performed at the study centre.

RESULTS

In the nine right lobe recipients, 10-year patient and graft survival rates were both 74%. There were no vascular complications, one biliary complication and one re-exploration. In the nine left lobe recipients, 10-year patient and graft survival rates were 78% and 66%, respectively. Postoperative complications included six biliary complications, four of which required surgical revision and all of which occurred within 5 months of transplantation, and two vascular complications, including one early hepatic artery thrombosis (HAT) and one late HAT, one of which required retransplantation. Five left lobe recipients required re-exploration, and one patient developed small-for-size syndrome following SLT, which resolved with conservative measures.

CONCLUSIONS

True right/left ex vivo SLT remains a viable option for facilitating the expansion of the adult cadaver donor pool and allows for excellent patient and graft survival. Postoperative morbidity remains high, especially in recipients of the left lobe graft, and must be balanced with the benefits to be derived from transplant.

Liver transplantation using low-weight recipients from a graft split program

We present our experience with a split liver (SL) program shared with the children's liver transplantation (LT) program from 2 different hospitals in the use of partial grafts from cadaver donors in brain death. We describe an observational, retrospective study, which included patients who underwent a SL transplantation in our center between January 2006 and December 2012. Clinical variables were recorded of both donors and recipients and their data were analyzed using SPSS 19.0 software. Of a total of 204 LT, 4 (2%) patients were treated with a SL. The causes of LT were alcoholic cirrhosis in 2 cases, cryptogenic cirrhosis, and primary biliary cirrhosis (PBC). In all cases there was a temporary portocaval shunt. The confluence of the hepatic veins of the recipient was anastomosed to the donor vena cava and arterial anastomosis was performed. The reconstruction was hepato-choledochal in all cases. There were no cases of postreperfusion syndrome or vascular thrombosis and no retransplantation was necessary. Currently, 3 of the 4 cases are still alive. Death in the other patient was due to mesenteric ischemia. Our center has participated in the development of a protocol that considers the indication of this technique provided expert groups are involved in its development, regardless of hospital level. This will expand the pool of donors and partially solve the current problems with available grafting.

Segment 4 architecture and proposed parenchyma-wise technique for Ex vivo graft procurement and implantation

A parenchyma-wise technique for the ex vivo procurement of segment 4 (S4) grafts, based on the detailed architecture of the segment, is proposed. Eighteen normal, fresh livers from adult cadavers were injected differentially with colored latex; dissection casts were prepared; and the intricate architecture of S4 was studied. The portal vein elements of the sheath forming most of the inferior part of S4 (S4b) and the superficial major fraction of its superior part (S4a) arose constantly from the medial aspect of the umbilical part of the left portal vein branch. The arterial elements arose constantly from a branch, whose diameter ranged from 2.00 to 3.35 mm (mean = 2.61 ± 0.54 mm) and whose length ranged from 15.15 to 45.65 mm (mean = 27.98 ± 12.13 mm). The biliary elements coalesced as a single duct at the corner, which was formed from the umbilical and transverse parts of the left portal vein branch; the duct's diameter ranged from 2.90 to 6.85 mm (mean = 3.90 ± 1.34 mm). Theoretically, this parenchymal mass-S4b and the superficial fraction of S4a-could be procured for implantation in an infant, and the rest of the liver could be split for an adult and a child. The portal vein branches of the graft would be procured with a patch from the medial aspect of the donor's umbilical portion of the left portal vein branch. This umbilical portion would be reconstructed with a patch from the donor's round ligament. The recipient's portal vein would be reconstructed through the fashioning of a conduit anastomosed with the graft's venous patch.

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.

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.

Trends in liver transplantation 2011

This review will highlight some of the important recent trends in liver transplantation. When possible, we will compare and contrast these trends across various regions of the world, in an effort to improve global consensus and better recognition of emerging data.

Imaging of preoperative liver transplantation in adults: what radiologists should know

Therapeutic strategies for treating patients with liver failure, particularly optimization of liver transplantation, are constantly being refined, with the goal of improving long-term survival with the lowest risk for toxicity in donors and recipients. Optimal planning for liver transplantation requires a multidisciplinary collaboration between the radiologist, hepatologist, clinical oncologist, and transplant surgeon. Radiologists play an essential role in identifying normal and abnormal variant anatomy and other conditions that may be present, a task that is critical for accurate surgical planning. Radiologists also must understand how their findings affect patient preparation. An awareness of the range of indications for liver transplantation, imaging modalities, and current surgical techniques is important to properly evaluate a patient who may undergo liver transplantation. Establishing a pretransplantation definition of the extent of liver disease and thoroughly evaluating the vascular and biliary anatomy are paramount for proper assessment of potential recipients and donors for liver transplantation.

The challenges of liver transplantation for hepatocellular carcinoma on cirrhosis

Hepatocellular carcinoma (HCC) is a major cause of cancer mortality worldwide and liver transplantation (LT) has potentials to improve survival for patients with HCC. However, expansion of indications beyond Milan Criteria (MC) and use of bridging/downstaging procedures to convert intermediate-advanced stages of HCC within MC limits are counterbalanced by graft shortage and increasing use of marginal donors, partially limited by the use of donor-division protocols applied to the cadaveric and living-donor settings. Several challenges in technique, indications, pre-LT treatments and prioritization policies of patients on the waiting list have to be precised through prospective investigations that have to include individualization of prognosis, biological variables and pathology surrogates as stratification criteria. Also, liver resection has to be rejuvenated in the general algorithm of HCC treatment in the light of salvage transplantation strategies, while benefit of LT for HCC should be determined through newly designed composite scores that are able to capture both efficiency and equity endpoints. Innovative treatments such as radioembolization for HCC associated with portal vein thrombosis and molecular targeted compounds are likely to influence future strategies. Accepting this challenge has been part of the history of LT and will endure so also for the future.

Modified pediatric end-stage liver disease scoring system and pediatric liver transplantation in Brazil

The Pediatric End-Stage Liver Disease (PELD) scoring system is a formula developed to provide a continuous numerical assessment of the risk of death in order to allocate livers to children in need of transplantation. The PELD scoring system was introduced in Brazil in July 2006. An important change was made in the system: the final number for listing patients less than 12 years old for transplantation was the calculated PELD score multiplied by 3. The consequences of this allocation policy were analyzed in 2 ways in this research: nationally and in the state of São Paulo (SP State). In the analysis of the national data, a comparison of the pre-PELD era (July 2003 to July 2006) and the post-PELD era (August 2006 to April 2009) showed that the total number of pediatric transplants for children under 12 years of age decreased 7%. Regionally, in SP State, there was a 62% increase in the number of deceased donor liver transplantation procedures for the pediatric population after the introduction of the modified PELD system. There was also a 6.1-fold increase in split liver transplantation as well as a statistically significant decrease in the time on the waiting list (P < 0.001). In conclusion, changing the allocation policy in Brazil in order to benefit pediatric patients on the waiting list had different results according to analyses of national and regional data. A significant increase in deceased donor liver transplantation/split liver transplantation and a shorter time on the waiting list were observed in SP State. The modified PELD scoring system is simple and optimizes the utilization of deceased donor liver grafts in centers performing pediatric transplants.

Outcomes in adult recipients of right-sided liver grafts in split-liver procedures

BACKGROUND

The split-liver technique provides a good left lateral graft in children, but its results in adults remain controversial.

METHODS

From 1992 to 2007, 37 patients received 38 cadaveric right-sided grafts. Donors and recipients were selected for good quality grafts and elective indications; the latter included a high proportion of tumour cases and primary sclerosing cholangitis. Grafts included 31 extended right grafts (ERGs; segments IV-VIII and I and the inferior vena cava [IVC]) and seven right grafts (RGs; segments V-VIII) including five without the IVC and middle hepatic vein (MHV).

RESULTS

Mortality was 5% (two patients). There were four retransplantations (11%) for arterial thrombosis (1), portal vein thrombosis (2) and primary non-function (1). The retransplantation rate was higher in RG than in ERG (three vs. one patient; P= 0.015). Of the five patients without MHV, three were retransplanted and one had small-for-size syndrome leading to late death. After a mean follow-up of 5 years, 1-, 3- and 5-year graft and patient survival rates were 84%, 80% and 71%, and 91%, 88% and 78%, respectively. One-year patient and graft survival rates after ERG transplantation were 96% and 92%, respectively.

CONCLUSIONS

Split-liver transplantation is a safe alternative to whole organ transplantation when an ERG is carried out. Right graft is associated with increased risk of graft loss, especially if the MHV is omitted. Split-liver transplantation with an ERG offers excellent outcomes and should be encouraged when good quality grafts are available.

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.

Longterm outcomes for whole and segmental liver grafts in adult and pediatric liver transplant recipients: a 10-year comparative analysis of 2,988 cases

BACKGROUND

Data on longterm outcomes after liver transplantation with partial grafts are limited. We compared 10-year outcomes for liver transplant patients who received whole grafts (WLT), split grafts from deceased donors (SLT), and partial grafts from living donors (LDLT).

STUDY DESIGN

We conducted a single-center analysis of 2,988 liver transplantations performed between August 1993 and May 2006 with median followup of 5 years. Graft types included 2,717 whole-liver, 181 split-liver, and 90 living-donor partial livers. Split-liver grafts included 109 left lateral and 72 extended right partial livers. Living-donor grafts included 49 left lateral and 41 right partial livers.

RESULTS

The 10-year patient survivals for WLT, SLT, and LDLT were 72%, 69%, and 83%, respectively (p=0.11), and those for graft survival were 62%, 55%, and 65%, respectively (p=0.088). There were differences in outcomes between adults and children when compared separately by graft types. In adults, 10-year patient survival was significantly lower for split extended right liver graft compared with adult whole liver and living-donor right liver graft (57% versus 72% versus 75%, respectively, p=0.03). Graft survival for adults was similar for all graft types. Retransplantation, recipient age older than 60 years, donor age older than 45 years, split extended right liver graft, and cold ischemia time>10 hours were predictors of diminished patient survival outcomes. In children, the 10-year patient and graft survivals were similar for all graft types.

CONCLUSIONS

Longterm graft survival rates in both adults and children for segmental grafts from deceased and living donors are comparable with those in whole organ liver transplantation. In adults, patient survival was lower for split compared with whole grafts when used in retransplantations and in critically ill recipients. Split graft-to-recipient matching is crucial for optimal organ allocation and best use of a scarce and precious resource.

Split-liver transplantation: an underused resource in liver transplantation

Split-liver transplantation is an efficient tool to increase the number of liver grafts available for transplantation. More than 15 years after its introduction only the classical splitting technique has reached broad application. Consequently children are benefiting most from this possibility. Full-right full-left splitting for two adult recipients has been shown to work but is hampered mainly by the dangers of small-for-size transplantation. A solution to this last problem would completely change the scope of split-liver transplantation. Organ allocation systems and collaboration between centers play a crucial role in the chances to let suitable patients profit from this valuable source of extra grafts.

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

The role of split-liver transplantation (SLT) for two adult recipients is still a matter of debate, and no agreement exists on indications, surgical techniques, and results. The aim of this study was to retrospectively analyze the outcome of our series of SLT. From May 1999 to December 2006, 16 patients underwent SLT at our unit. We used 9 full right grafts (segments 5-8) and 7 full left grafts (segments 1-4). The splitting procedure was always carried out in situ with a fully perfused liver. Postoperative complications were recorded in 8 (50%) patients: 5 (55%) in full right grafts and 3 (43%) in full left grafts. No one was retransplanted. After a median follow-up of 55.82 months (range, 0.4-91.2), 5 (31%) patients died, and the 1-, 3-, and 5-year overall survival rate for patients and grafts was 69%. We considered as a control group for the global outcome 232 whole liver transplantations performed at our unit in the same period of time. Postoperative complications were recorded in 53 (23%) patients, and after a median follow-up of 57.37 months (mean, 55.11; range, 1-102.83), the 1-, 3-, and 5-year overall patient survival was 87%, 82%, and 80%, respectively. In conclusion, SLT for two adult recipients is a technically demanding procedure that requires complex logistics and surgical teams experienced in both liver resection and transplantation. Although the reported rate of survival might be adequate for such a procedure, more efforts have to be made to improve the short-term outcome, which is inadequate in our opinion. The true feasibility of SLT for two adults has to be considered as still under investigation.

The marginal liver donor--an update

The number of patients awaiting liver transplantation keeps steadily rising with no corresponding rise in suitable grafts for transplantation. There also is an increasing trend of patients dying or being taken off waiting lists because of deterioration while waiting for a transplant. Over the preceding years the use of marginal grafts in liver transplantation has been driven by the critical shortage of donor organs and by emerging data that their use has resulted in a favourable outcome. This review revisits the factors defining marginality of a graft, and the issues faced by transplant units in making the decision to use such a graft. It also looks at the innovations in transplantation geared towards increasing the donor pool and the resulting issues of matching marginal grafts to suitable recipients.

Reducing bile leak following segmental liver transplantation: understanding biliary anatomy of the caudate lobe

Bile leak in split and living donor liver transplantation is not an uncommon postoperative complication with significant morbidity to both donor and recipients. Nonanastomotic bile leaks in these transplants are less well characterized and generally described as cut-surface leaks. A proportion of these leaks may derive from biliary radicles draining the caudate lobe. Based on the caudate lobe biliary anatomy the authors describe measures that may help to reduce such complications after segmental liver transplantation.

Split Liver Network: A Collaborative Internet-Based Scenario to Expand the Organ Pool

BACKGROUND

Split liver transplantation (SLT) has become a crucial option to maximize the liver pool, while organ procurement organizations (OPOs) usually allocate whole livers to single centers. In 2003, Italian Ministry of Health funded the Innovative Strategies to Expand Cadaveric Donor Pool for Liver Transplantation project with the goal to establish sharing criteria for SLT for two adults (SLT A/A), involving Italian transplantation centers, the North Italy Transplant OPO, and the Italian National Transplant Center.

METHODS

SITF group defined donor/recipient inclusion criteria, setting minimum graft/recipient weight ratio (GRWR) at 1.2%. Donors and recipients on waiting list were shared on an Internet secured Web-based application (Split Liver Network [SLN]). SLN performs real-time matches between the registered donor and all patients on the bases of GRWR, displaying a size-based list of matched donor/patients, figuring hemiliver allocation once the whole organ is referred to a specific center.

RESULTS

In the 2005 period, 47 donors and 124 patients were entered by nine centers, and six hemiliver allocations for three SLT A/A procedures were performed. By retrospective simulation of 32 donors and 613 recipients in the Nord Italia Transplant area, matchable recipients were available for all donors, while blood group frequency seemed a determining factor, more than donor body weight.

COMMENTS

SLN hemiliver allocation might increase matching possibilities, offering a timely transplant for recipients of rare group, small-size, or in need of short wait. Our experience suggests that such an environment may be helpful to share a macroregional pool of liver recipients and to optimize SLT.