Routine utilization of machine perfusion in liver transplantation:Ready for prime time?

The last decade has been notable for increasing high-quality research and dramatic improvement in outcomes with dynamic liver preservation.Robust evidence from numerous randomized controlled trials has been pooled by meta-analyses,providing the highest available evidence on the protective effect of machine perfusion(MP)over static cold storage in liver transplantation(LT).Based on a protective effect with less complications and improved graft survival,the field has seen a paradigm shift in organ preservation.This editorial focuses on the role of MP in LT and how it could become the new“gold standard”.Strong collaborative efforts are needed to explore its effects on long-term outcomes.

Machine perfusion of the liver:Putting the puzzle pieces together

The realm of extended criteria liver transplantation created the'adjacent possible'for dynamic organ preservation.Machine perfusion of the liver greatly expanded donor organ preservation possibilities,reaching before unattainable goals,including the mitigation of ischemia-reperfusion injury,viability assessment,and organ reconditioning prior to transplantation.However,current scientific evidence lacks uniformity between studies,perfusion protocols,and acceptance criteria.Construction of collaborative research networks for sharing knowledge should,therefore,enable the development of high-level evidence and guidelines for machine perfusion utilization,including donor acceptance criteria.Finally,this approach shall guarantee conditions for further progress to occur.

Large Riedel’s lobe and atrophic left liver in a donor-Accept for transplant or call off?

BACKGROUND In context of suboptimal liver utilisation,grafts with various risk factors are under consideration today.For example,impaired vascularity with severe arterial calcifications and modified liver shapes are no longer contraindications and their use depends on the centre policy and experience of the surgical team.Riedel liver lobes represent a tongue-like liver shape with inferior projection in the right liver lobe.Such development modifications were initially described when patients developed a lesion and subsequently presented with symptoms.We here present the first case report in the literature,where such livers with anatomical variations were used for transplantation.CASE SUMMARY We describe here two cases of adult human liver transplantation,where we have accepted two donor livers with modified shape.The technical considerations for transplantation of such livers,found with enlarged right lobes,or Riedel shape,and hypo-trophic left lateral segment are highlighted.Both recipients experienced immediate liver function and overall good outcomes with a minimum follow up of 1 year.We also provide detailed pictures and outcome analysis in combination with a literature review.CONCLUSION The utilisation of donor livers with modified shape,such as Riedel’s Lobe appears safe and will increase the donor pool.

Development and internal validation of the Comprehensive ALPPS Preoperative Risk Assessment(CAPRA)score:is the patient suitable for Associating Liver Partition and Portal vein ligation for Staged hepatectomy(ALPPS)?

Background:Preoperative patient selection in Associating Liver Partition and Portal vein ligation for Staged hepatectomy(ALPPS)is not always reliable with currently available scores,particularly in patients with primary liver tumor.This study aims to(I)to determine whether comorbidities and patients characteristics are a risk factor in ALPPS and(II)to create a score predicting 90-day mortality preoperatively.Methods:Thirteen high-volume centers participated in this retrospective multicentric study.A risk analysis based on patient characteristics,underlying disease and procedure type was performed to identify risk factors and model the Comprehensive ALPPS Preoperative Risk Assessment(CAPRA)score.A nonparametric receiver operating characteristic analysis was performed to estimate the predictive ability of our score against the Charlson Comorbidity Index(CCI),the age-adjusted CCI(aCCI),the ALPPS risk score before Stage 1(ALPPS-RS1)and Stage 2(ALPPS-RS2).The model was internally validated applying bootstrapping.Results:A total of 451 patients were included.Mortality was 14.4%.The CAPRA score is calculated based on the following formula:(0.1×age)−(2×BSA)+1(in the presence of primary liver tumor)+1(in the presence of severe cardiovascular disease)+2(in the presence of moderate or severe diabetes)+2(in the presence of renal disease)+2(if classic ALPPS is planned).The predictive ability was 0.837 for the CAPRA score,0.443 for CCI,0.519 for aCCI,0.693 for ALPPS-RS1 and 0.807 for ALPPS-RS2.After 1,000 cycles of bootstrapping the C statistic was 0.793.The accuracy plot revealed a cut-off for optimal prediction of postoperative mortality of 4.70.Conclusions:Comorbidities play an important role in ALPPS and should be carefully considered when planning the procedure.By assessing the patient’s preoperative condition in relation to ALPPS,the CAPRA score has a very good ability to predict postoperative mortality.

Machine perfusion strategies in liver transplantation

Machine perfusion is a hot topic in liver transplantation and several new perfusion conceptsare currently developed.Prior to introduction into routine clinical practice,however,such perfusionapproaches need to demonstrate their impact on liver function,post-transplant complications,utilizationrates of high-risk organs,and cost benefits.Therefore,based on results of experimental and clinical studies,the community has to recognize the limitations of this technology.In this review,we summarize currentperfusion concepts and differences between protective mechanisms of ex-and in-situ perfusion techniques.Next,we discuss which graft types may benefit most from perfusion techniques,and highlight the currentunderstanding of liver viability testing.Finally,we present results from recent clinical trials involvingmachine liver perfusion,and analyze the value of different outcome parameters,currently used as endpointsfor randomized controlled trials in the field.