The 'small for size' liver syndrome

Post-hepatectomy liver failure: A timeline centered review

BACKGROUND

Post-hepatectomy liver failure (PHLF) is a leading cause of postoperative mortality after liver surgery. Due to its significant impact, it is imperative to understand the risk stratification and preventative strategies for PHLF. The main objective of this review is to highlight the role of these strategies in a timeline centered way around curative resection.

DATA SOURCES

This review includes studies on both humans and animals, where they addressed PHLF. A literature search was conducted across the Cochrane Library, Embase, MEDLINE/PubMed, and Web of Knowledge electronic databases for English language studies published between July 1997 and June 2020. Studies presented in other languages were equally considered. The quality of included publications was assessed using Downs and Black's checklist. The results were presented in qualitative summaries owing to the lack of studies qualifying for quantitative analysis.

RESULTS

This systematic review with 245 studies, provides insight into the current prediction, prevention, diagnosis, and management options for PHLF. This review highlighted that liver volume manipulation is the most frequently studied preventive measure against PHLF in clinical practice, with modest improvement in the treatment strategies over the past decade.

CONCLUSIONS

Remnant liver volume manipulation is the most consistent preventive measure against PHLF.

Synergy of 5-aminolevulinate supplement and CX3CR1 suppression promotes liver regeneration via elevated IGF-1 signaling

Inadequate remnant volume and regenerative ability of the liver pose life-threatening risks to patients after partial liver transplantation (PLT) or partial hepatectomy (PHx), while few clinical treatments focus on safely accelerating regeneration. Recently, we discovered that supplementing 5-aminolevulinate (5-ALA) improves liver cold adaptation and functional recovery, leading us to uncover a correlation between 5-ALA metabolic activities and post-PLT recovery. In a mouse 2/3 PHx model, 5-ALA supplements enhanced liver regeneration, promoting infiltration and polarization of anti-inflammatory macrophages via P53 signaling. Intriguingly, chemokine receptor CX3CR1 functions to counterbalance these effects. Genetic ablation or pharmacological inhibition of CX3CR1 (AZD8797; phase II trial candidate) augmented the macrophagic production of insulin-like growth factor 1 (IGF-1) and subsequent hepatocyte growth factor (HGF) production by hepatic stellate cells. Thus, short-term treatments with both 5-ALA and AZD8797 demonstrated pro-regeneration outcomes superior to 5-ALA-only treatments in mice after PHx. Overall, our findings may inspire safe and effective strategies to better treat PLT and PHx patients.

Distinct hepatocyte identities in liver homeostasis and regeneration

The process of metabolic liver zonation is spontaneously established by assigning distributed tasks to hepatocytes along the porto-central blood flow. Hepatocytes fulfil critical metabolic functions, while also maintaining hepatocyte mass by replication when needed. Recent technological advances have enabled us to fine-tune our understanding of hepatocyte identity during homeostasis and regeneration. Subsets of hepatocytes have been identified to be more regenerative and some have even been proposed to function like stem cells, challenging the long-standing view that all hepatocytes are similarly capable of regeneration. The latest data show that hepatocyte renewal during homeostasis and regeneration after liver injury is not limited to rare hepatocytes; however, hepatocytes are not exactly the same. Herein, we review the known differences that give individual hepatocytes distinct identities, recent findings demonstrating how these distinct identities correspond to differences in hepatocyte regenerative capacity, and how the plasticity of hepatocyte identity allows for division of labour among hepatocytes. We further discuss how these distinct hepatocyte identities may play a role during liver disease.

Study of ultrasound-guided percutaneous microwave ablation combined with portal vein embolization for rapid future liver remnant increase of planned hepatectomy

Purpose

To evaluate the efficacy of ultrasound-guided percutaneous microwave ablation (PMA) combined with portal vein embolization (PVE) for planned hepatectomy.

Methods

We retrospectively reviewed data of 18 patients with multiple right liver tumors or hilar tumor of liver invades the surrounding tissue and insufficient future liver remnant (FLR) for hepatectomy from July 2015 to March 2017. Ultrasound-guided PMA was performed by using PMCT cold circulation microwave treatment apparatus. PVE was performed after PMA. The increase of FLR was evaluated by computed tomography (CT) 6-22 days after PVE. The proportion of FLR, increase in the amplitude of FLR, procedure-related complications, perioperative morbidity and mortality, and overall survival (OS) rates, the median survival time were analyzed.

Results

The median volume of FLR before PMA and PVE was 369.7 ml (range: 239.4-493.1 ml). After a median waiting period of 11.5 days (range: 6-22 days), the median volume of FLR was increased to 523.4 ml (range: 355.4-833.3 ml). The changes in FLR before and after PMA and PVE were statistically significant (p<0.001). No serious perioperative complications or mortality were found. After a median follow-up time of 51.0 months (range: 2-54 months), the 6-month, 1-year, 2-year, 3-year and 4-year survival rates were 88.9%, 72.2%, 44.4%, 33.3%, 22.2%, respectively, and the median survival time was 15.0 ± 7.1 months.

Conclusion

PMA combined with PVE increases FLR rapidly, avoids touching malignant tumors, and produces fewer procedure-related complications. It appears safe and efficacious for planned hepatectomy.

Colorectal Cancer Liver Metastases: Multimodal Therapy

Despite a steady decline in incidence and mortality rates, colorectal cancer (CRC) remains the second most common cancer diagnosis in women and the third most common in men worldwide. Notably, the liver is recognized as the most common site of CRC metastasis, and metastases to the liver remain the primary driver of disease-specific mortality for patients with CRC. Although hepatic resection is the backbone of curative-intent treatment, management of CRLM has become increasingly multimodal during the last decade and includes the use of downstaging chemotherapy, ablation techniques, and locoregional therapy, each of which are reviewed herein.

Minimizing the risk of small-for-size syndrome after liver surgery

BACKGROUND

Primary and secondary liver tumors are not always amenable to resection due to location and size. Inadequate future liver remnant (FLR) may prevent patients from having a curative resection or may result in increased postoperative morbidity and mortality from complications related to small-for-size syndrome (SFSS).

DATA SOURCES

This comprehensive review analyzed the principles, mechanism and risk factors associated with SFSS and presented current available options in the evaluation of FLR when planning liver surgery. In addition, it provided a detailed description of specific modalities that can be used before, during or after surgery, in order to optimize the conditions for a safe resection and minimize the risk of SFSS.

RESULTS

Several methods which aim to reduce tumor burden, preserve healthy liver parenchyma, induce hypertrophy of FLR or prevent postoperative complications help minimize the risk of SFSS.

CONCLUSIONS

With those techniques the indications of radical treatment for patients with liver tumors have significantly expanded. The successful outcome depends on appropriate patient selection, the individualization and modification of interventions and the right timing of surgery.

HPi: A Novel Parameter to Predict Graft-related Outcome in Adult Living Donor Liver Transplant

BACKGROUND

Portal hyperperfusion is frequently associated with early allograft dysfunction (EAD). It is imperative to identify patients who would require portal inflow modulation. We aimed to identify factors associated with hyperperfusion-related graft injury and develop a predictive index for the same.

METHODS

Prospectively maintained database was queried to identify 135 adult living donor liver transplant recipients between September 2016 and July 2020. According to the calculated sample size, 96 patients were randomly selected for "test cohort". The remaining 39 patients made the "validation cohort." EAD was defined according to the A2ALL study. "Hyperperfusion index (HPi)," defined as posttransplant portal pressure gradient (ΔPpost)/graft-to-recipient splenic volume ratio (GRSVR), was devised on the basis of laws of flow dynamics and regression analysis.

RESULTS

Overall, 40 patients (29.6%) had EAD, six 90-d mortalities (4.4%) were attributable to EAD. In the test cohort, EAD patients (n = 29, 30.2%) had lower GRSVR (1.00 versus 2.22, P < 0.001), higher ΔPpost (14.8 versus 11.9, P = 0.004), and HPi (20.89 versus 8.67, P < 0.001). Multivariate analysis revealed GRSVR, ΔPpost, and HPi as significant factors to predict EAD. Receiver operating characteristic determined cutoff of HPi ≥9.97 could predict EAD with sensitivity of 90% and specificity of 73% (F-score = 0.712). HPi ≥16.25 predicted 90-d mortality with sensitivity of 100% and specificity of 78.9%. Patients with higher HPi had delayed graft-related recovery. Non-EAD patients had a higher 1-y (96% versus 79%) and 2-y (88% versus 79%) survival. The cutoff of HPi was validated well in the validation cohort (F-score = 0.645) (Hosmer-Lemeshow test, P = 0.89).

CONCLUSIONS

While predicted GRSVR may help identify at-risk patients preoperatively, intraoperatively calculated HPi is more accurate in identifying patients who would require portal inflow modulation. Achieving an HPi below target cutoff significantly decreases the risk of EAD even in low-GRSVR patients.

Dualistic role of platelets in living donor liver transplantation: Are they harmful?

Platelets are anucleate fragments mainly involved in hemostasis and thrombosis, and there is emerging evidence that platelets have other nonhemostatic potentials in inflammation, angiogenesis, regeneration and ischemia/reperfusion injury (I/R injury), which are involved in the physiological and pathological processes during living donor liver transplantation (LDLT). LDLT is sometimes associated with impaired regeneration and severe I/R injury, leading to postoperative complications and decreased patient survival. Recent studies have suggested that perioperative thrombocytopenia is associated with poor graft regeneration and postoperative morbidity in the short and long term after LDLT. Although it is not fully understood whether thrombocytopenia is the cause or result, increasing platelet counts are frequently suggested to improve posttransplant outcomes in clinical studies. Based on rodent experiments, previous studies have identified that platelets stimulate liver regeneration after partial hepatectomy. However, the role of platelets in LDLT is controversial, as platelets are supposed to aggravate I/R injury in the liver. Recently, a rat model of partial liver transplantation (LT) was used to demonstrate that thrombopoietin-induced thrombocytosis prior to surgery accelerated graft regeneration and improved the survival rate after transplantation. It was clarified that platelet-derived liver regeneration outweighed the associated risk of I/R injury after partial LT. Clinical strategies to increase perioperative platelet counts, such as thrombopoietin, thrombopoietin receptor agonist and platelet transfusion, may improve graft regeneration and survival after LDLT.

Evidence on Indications and Techniques to Increase the Future Liver Remnant in Children Undergoing Extended Hepatectomy: A Systematic Review and Meta-Analysis of Individual Patient Data

BACKGROUND

Techniques to increase the future liver remnant (FLR) have fundamentally changed the indications and criteria of resectability in adult liver surgery. In pediatric patients however, these procedures have rarely been applied and the potential benefit or harm as well as suited indications are unclear.

METHODS

A systematic literature search of MEDLINE, Web of Science, and CENTRAL was conducted. Based on a PRISMA-compliant, predefined methodology, all studies reporting pediatric patients (< 18y) undergoing liver resection with either associating liver partition and portal vein ligation for stages hepatectomy (ALPPS) or preoperative portal vein embolization or ligation (PVE/PVL) were included. Baseline data, periinterventional morbidity, increase of FLR and outcomes were analyzed.

RESULTS

15 studies reporting on 21 pediatric patients with a mean age of 4 years and 7 months (range 1.8 months - 17 years) were included. 12 ALPPS procedures, 8 PVE and 1 PVL were performed. The applied criteria for performing ALPPS or PVE were heterogenous and thresholds for minimally acceptable FLR varied. Mean FLR [% of total liver volume] before the intervention was 23.6% (range 15.0 - 39.3%) in the ALPPS group and 31.4% (range 21.5 - 56.0%) in the PVE group. Mean increase of FLR before stage 2 resection was 69.4% (range 19.0 - 103.8%) for ALPPS and 62.8% (range 25.0 - 108.0%) after PVE. No postoperative death occurred, one early intrahepatic recurrence after an ALPPS procedure was reported. Overall postoperative morbidity was 23.8%.

CONCLUSION

Validated criteria for minimal FLR in pediatric liver resection are lacking and so are clear indications for ALPPS or PVE. In special cases, ALPPS and PVE can be valuable techniques to achieve complete resection of pediatric liver tumors. However, more data are needed, and future studies should focus on a definition and validation of posthepatectomy liver failure as well as the minimally needed FLR in pediatric patients undergoing extended hepatectomy.

SYSTEMATIC REVIEW REGISTRATION

[www.clinicaltrials.gov], identifier [PROSPERO 2021 CRD42021274848].

Current strategies to induce liver remnant hypertrophy before major liver resection

Hepatic resection is the gold standard for patients affected by primary or metastatic liver tumors but is hampered by the risk of post-hepatectomy liver failure. Despite recent improvements, liver surgery still requires excellent clinical judgement in selecting patients for surgery and, above all, efficient pre-operative strategies to provide adequate future liver remnant. The aim of this article is to review the literature on the rational, the preliminary assessment, the advantages as well as the limits of each existing technique for preparing the liver for major hepatectomy.

Outcomes of Highly Selected Live Donors With a Future Liver Remnant Less Than or Equal to 30%: A Matched Cohort Study

BACKGROUND

The main concern with live donor liver transplantation (LDLT) is the risk to the donor. Given the potential risk of liver insufficiency, most centers will only accept candidates with future liver remnants (FLR) >30%. We aimed to compare postoperative outcomes of donors who underwent LDLT with FLR ≤30% and >30%.

METHODS

Adults who underwent right hepatectomy for LDLT between 2000 and 2018 were analyzed. Remnant liver volumes were estimated using hepatic volumetry. To adjust for between-group differences, donors with FLR ≤30% and >30% were matched 1:2 based on baseline characteristics. Postoperative complications including liver dysfunction were compared between the groups.

RESULTS

A total of 604 live donors were identified, 28 (4.6%) of whom had a FLR ≤30%. Twenty-eight cases were successfully matched with 56 controls; the matched cohorts were mostly similar in terms of donor and graft characteristics. The calculated median FLR was 29.8 (range, 28.0-30.0) and 35.2 (range, 30.1-68.1) in each respective group. Median follow-up was 36.5 mo (interquartile range, 11.8-66.1). Postoperative outcomes were similar between groups. No difference was observed in overall complication rates (FLR ≤30%: 32.1% versus FLR >30%: 28.6%; odds ratio [OR], 1.22; 95% confidence interval [CI], 0.46-3.27) or major complication rates (FLR ≤30%: 14.3% versus FLR >30%: 14.3%; OR, 1.17; 95% CI, 0.33-4.10). Posthepatectomy liver failure was rare, and no difference was observed (FLR ≤30%: 3.6% versus FLR >30%: 3.6%; OR, 1.09; 95% CI, 0.11-11.1).

CONCLUSION

A calculated FLR between 28% and 30% on its own should not represent a formal contraindication for live donation.

The hippo pathway: A master regulator of liver metabolism, regeneration, and disease

The liver is the only visceral organ in the body with a tremendous capacity to regenerate in response to insults that induce inflammation, cell death, and injury. Liver regeneration is a complicated process involving a well-orchestrated activation of non-parenchymal cells in the injured area and proliferation of undamaged hepatocytes. Furthermore, the liver has a Hepatostat, defined as adjustment of its volume to that required for homeostasis. Understanding the mechanisms that control different steps of liver regeneration is critical to informing therapies for liver repair, to help patients with liver disease. The Hippo signaling pathway is well known for playing an essential role in the control and regulation of liver size, regeneration, stem cell self-renewal, and liver cancer. Thus, the Hippo pathway regulates dynamic cell fates in liver, and in absence of its downstream effectors YAP and TAZ, liver regeneration is severely impaired, and the proliferative expansion of liver cells blocked. We will mainly review upstream mechanisms activating the Hippo signaling pathway following partial hepatectomy in mouse model and patients, its roles during different steps of liver regeneration, metabolism, and cancer. We will also discuss how targeting the Hippo signaling cascade might improve liver regeneration and suppress liver tumorigenesis.

Ligation of the middle hepatic vein to increase hypertrophy induction during the ALPPS procedure

PURPOSE

Here, we analyse the technical modification of the ALPPS procedure, ligating the middle hepatic vein during the first step of the operation to enhance remnant liver hypertrophy.

METHODS

In 20 of 37 ALPPS procedures, the middle hepatic vein was ligated during the first step. Hypertrophy of the functional remnant liver volume was assessed in addition to postoperative courses.

RESULTS

Volumetric analysis showed a significant volume increase, especially for patients with colorectal metastases. Pre-existing liver parenchyma damage (odds ratio = 0.717, p = 0.017) and preoperative chemotherapy were found to be significant predictors (odds ratio = 0.803, p = 0.045) of higher morbidity and mortality. In addition, a survival benefit for maintenance of middle hepatic vein was shown.

CONCLUSION

This technical modification of the ALPPS procedure can accentuate future liver remnant volume hypertrophy. The higher morbidity and mortality observed are most likely associated with pre-existing parenchymal damage within this group.

Impact of diseased liver parenchyma on perioperative outcome among patients with hepatocellular carcinoma undergoing hepatectomy: Experience from a developing country

INTRODUCTION

Limited data can be found about surgical outcome of patients with hepatocellular carcinoma (HCC) arising in non-diseased liver. The study aim was to compare short- and long-term outcomes among HCC patients with normal and diseased liver parenchyma, undergoing potentially curative liver resection in a developing country.

MATERIALS AND METHODS

From November 2001 until January 2017, 228 patients with HCC underwent curative-intent hepatectomy at the University Clinic for Digestive Surgery. From that number, 190 patients were eligible for analysis. Diseased liver (DL) was present in 112 patients while 78 patients had HCC in non-diseased liver (NDL).

RESULTS

Median age, sex, ASA score, the presence of extrahepatic disease and lobar distribution of tumors were similar in both groups. The number of tumors was higher in DL group, while tumor diameter was higher in NDL group. Anatomic liver resection and major liver resections were performed more commonly in NDL than in DL group (66.7 vs 47.4%, p = 0.008; 33.3 vs. 15.2%, p = 0.003). Postoperative morbidity was significantly higher in DL group (p = 0.004). Overall survival was statistically longer in NDL group (p = 0.024). By univariate analysis potential prognostic factors for long-term survival were identified: presence of chronic HCV infection, presence of cirrhosis, Child-Pugh score B and operative time longer than 240 min. The last two were confirmed by multivariate analysis as independent negative prognostic factors for overall survival.

CONCLUSION

Liver resection in patients with HCC arising in non-diseased livers, despite of need for extended hepatectomies, provides favorable long-term prognosis.

A Novel Method for the Prevention and Treatment of Small-for-Size Syndrome in Liver Transplantation

BACKGROUND

Currently there is no consensus on the optimal management of small-for-size syndrome following liver transplantation. Here we describe a technique to alleviate portal hypertension and improve the hepatocyte reperfusion in small-for-size liver transplantation in a Lewis rat model.

METHODS

The rats underwent trans-portal vein intra-hepatic portosystemic shunt using a self-developed porous conical tube (TPIPSS: Fig. 1) on small-for-size liver transplants (SFS) with right lobe graft. The treatment effect was evaluated by comparing hemodynamic parameters, morphological changes, serum parameters, ET-1 and eNOS expression, hepatocyte proliferation and apoptosis, CYP3A2 levels, postoperative complications, and survival between the two groups with SFS liver transplants.

RESULTS

Porous conical prosthesis prolonged the filling time of small-for-size grafts. Moreover, grafts with TPIPSS showed a lower portal vein pressure, improved microcirculatory flow, alleviated histological changes, decreased ET-1 and increased eNOS expressions, and significantly less damage to liver function comparing to grafts without TPIPSS. Mean survival and overall 30-day survival were significantly higher in the TPIPSS group.

CONCLUSIONS

These results demonstrate that porous conical tube as trans-portal vein intra-hepatic portosystemic shunt device is an effective way to alleviate portal vein hypertension and improve hepatocyte reperfusion after small-for-size liver transplantation.

Associated liver partition and portal vein ligation for staged hepatectomy: a review

Outcomes of liver resection have improved with advances in surgical techniques, improvements in critical care and expansion of resectability criteria. However, morbidity and mortality following liver resection continue to plague surgeons. Post-hepatectomy liver failure (PHLF) due to inadequate future liver remnant (FLR) is an important cause of morbidity and mortality following liver resection. Associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) is a novel two-staged procedure described in 2012, which aims to induce rapid hypertrophy of the FLR unlike conventional two-stage hepatectomy, which require a longer time for FLR hypertrophy. Careful patient selection and modifications in surgical technique has improved morbidity and mortality rates in ALPPS. Colorectal liver metastases (CRLM) confers the best outcomes post-ALPPS. Patients <60 years old and low-grade fibrosis with underlying hepatocellular carcinoma (HCC) are also eligible for ALPPS. Evidence for other types of cancers is less promising. Current studies, though limited, demonstrate that ALPPS has comparable oncological outcomes with conventional two-stage hepatectomy. Modifications such as partial-ALPPS and mini-ALPPS have shown improved morbidity and mortality compared to classic ALPPS. ALPPS may be superior to conventional two-stage hepatectomy in carefully selected groups of patients and has a promising outlook in liver surgery.

Relationship Between Change Rate of Tacrolimus Clearance During Continuous Intravenous Infusion and Recipient Recovery at an Early Stage After Living Donor Liver Transplantation

BACKGROUND AND OBJECTIVE

Tacrolimus clearance (CL) is significantly altered according to recovery of liver function at an early stage after living donor liver transplantation (LDLT). In this study, we aimed to examine the impact of the change rate from postoperative day (POD) 1 in CL (ΔCL) of tacrolimus during continuous intravenous infusion (CIVI) on recipient recovery.

METHODS

A tacrolimus population pharmacokinetic model on POD1 after LDLT was developed using Phoenix NLME 1.3. The CL_POD1 was calculated using the final model. The CL_POD4-7 was calculated by dividing total daily tacrolimus dose by the area under the concentration-time curve from 0 to 24 h.

RESULTS

Data were obtained from 57 LDLT recipients, along with 540 points (177 points on POD1, 363 points on POD4-7) of tacrolimus whole blood concentrations at CIVI. The median tacrolimus CL decreased from POD1 to POD4 (from 2.73 to 1.40 L/h) and was then stable until POD7. Stepwise Cox proportional hazards regression analyses showed that the graft volume (GV)/standard liver volume (SLV) ratio (GV/SLV) and the tacrolimus ΔCL_POD6 were independent factors predicting early discharge (within 64 days median value) of recipients after LDLT [hazard ratio (HR) = 1.041, P = 0.001 and HR = 1.023, P = 0.004].

CONCLUSIONS

The tacrolimus ΔCL during CIVI immediately after LDLT in each recipient was a useful indicator for evaluation of recovery at an early stage after LDLT.

Clinical translation of liver regeneration therapies: A conceptual road map

The increasing incidence of severe liver diseases worldwide has resulted in a high demand for curative liver transplantation. Unfortunately, the need for transplants by far eclipses the availability of suitable grafts leaving many waitlisted patients to face liver failure and often death. Routine use of smaller grafts (for example left lobes, split livers) from living or deceased donors could increase the number of life-saving transplants but is often limited by the graft versus recipient weight ratio defining the safety margins that minimize the risk of small for size syndrome (SFSS). SFSS is a severe complication characterized by failure of a small liver graft to regenerate and occurs when a donor graft is insufficient to meet the metabolic demand of the recipient, leading to liver failure as a result of insufficient liver mass. SFSS is not limited to transplantation but can also occur in the setting of hepatic surgical resections, where life-saving large resections of tumors may be limited by concerns of post-surgical liver failure. There are, as yet no available pro-regenerative therapies to enable liver regrowth and thus prevent SFSS. However, there is optimism around targeting factors and pathways that have been identified as regulators of liver regeneration to induce regrowth in vivo and ex vivo for clinical use. In this commentary, we propose a roadmap for developing such pro-regenerative therapy and for bringing it into the clinic. We summarize the clinical indications, preclinical models, pro-regenerative pathways and safety considerations necessary for developing such a drug.

Liver Transplantation

The field of liver transplantation has changed since the MELD scoring system became the most widely used donor allocation tool. Due to the MELD-based allocation system, sicker patients with higher MELD scores are being transplanted. Persistent organ donor shortages remain a challenging issue, and as a result, the wait-list mortality is a persistent problem for most of the regions. This chapter focuses on deceased donor and live donor liver transplantation in patients with complications of portal hypertension. Special attention will also be placed on donor-recipient matching, perioperative management of transplant patients, and the impact of hepatic hemodynamics on transplantation.

Impact of small-for-size liver grafts on medium-term and long-term graft survival in living donor liver transplantation: A meta-analysis

BACKGROUND

Small-for-size grafts (SFSGs) in living donor liver transplantation (LDLT) could optimize donor postoperative outcomes and also expand the potential donor pool. Evidence on whether SFSGs would affect medium-term and long-term recipient graft survival is lacking.

AIM

To evaluate the impact of small-for-size liver grafts on medium-term and long-term graft survival in adult to adult LDLT.

METHODS

A systematic review and meta-analysis were performed by searching eligible studies published before January 24, 2019 on PubMed, EMBASE, and Web of Science databases. The primary outcomes were 3-year and 5-year graft survival. Incidence of small-for-size syndrome and short term mortality were also extracted.

RESULTS

This meta-analysis is reported according to the guidelines of the PRISMA 2009 Statement. Seven retrospective observational studies with a total of 1821 LDLT recipients were included in the meta-analysis. SFSG is associated with significantly poorer medium-term graft survival. The pooled odds ratio for 3-year graft survival was 1.58 [95% confidence interval 1.10-2.29, P = 0.014]. On the other hand, pooled results of the studies showed that SFSG had no significant discriminatory effect on 5-year graft survival with an odds ratio of 1.31 (95% confidence interval 0.87-1.97, P = 0.199). Furthermore, incidence of small-for-size syndrome detected in recipients of SFSG ranged from 0-11.4% in the included studies.

CONCLUSION

SFSG is associated with inferior medium-term but not long-term graft survival. Comparable long-term graft survival based on liver graft size shows that smaller grafts could be accepted for LDLT with appropriate flow modulatory measures. Close follow-up for graft function is warranted within 3 years after liver transplantation.

The outcome of the HCC patients underwent ALPPS: Retrospective study

The complete resection offers the best long-term survival for advanced hepatocellular carcinoma patients. ALPPS as a choice of resection, how is its outcome compared to one-stage resection, liver transplantation and TACE? This retrospective study included 20 ALPPS patients. To minimize the effect of confounding influences of measured covariates, PSM was performed. The overall survival (OS), morbidity, mortality and the increasing rate, KGR were analyzed. The OS in ALPPS group is 27.4 (±3.8 months) moths and the TACE group is 13.5(±1.2 months) (P < .001), LT group is 41.3 (±3.2 months) (P = .048), Resection group is 31.8 (±2.6 months) (P = .368). And the medium increasing volume is 209.5 cm (±61.5 cm) with the increasing ratio 52.4% (+26.9%). The ALPPS is a feasible treatment for HCC patients and it provides a better long-term survival than TACE and it is similar to Resection, less than LT.

Outcomes of staged hepatectomies for liver malignancy

Liver malignancies are the fifth most common cause of death worldwide. Surgical intervention with curative intent is the treatment of choice for liver tumors as it provides long-term survival. However, only 20% of patients with metastatic liver lesions can be managed by curative liver resection. In most of the cases, hepatectomy is not feasible because of insufficient future liver remnant (FLR). Two-stage hepatectomy is advocated to achieve liver resection in a patient who is considered to not be a candidate for resection. Procedures of staged hepatectomy include conventional two-stage hepatectomy, portal vein embolization, and associating liver partition and portal vein ligation for a staged hepatectomy. Technical success is high for each of these procedures but variable between them. All the procedures have been reported as being effective in achieving a satisfactory FLR and completing the second-stage resection. Moreover, the overall survival and disease-free survival rates have improved significantly for patients who were otherwise considered nonresectable; yet, an increase in the morbidity and mortality rates has been observed. We suggest that this type of procedure should be carried out in high-flow centers and through a multidisciplinary approach. An experienced surgeon is key to the success of those interventions.

Simulating Transplant Small-for-size Grafts Using Human Liver Monosegments: The Impact of Portal Perfusion Pressure

Small-for-size-liver grafts (SFSG) in adult transplant recipients have elevated risk of graft failure, limiting its application in clinical liver transplantation. Relevant preclinical model of SFSG is lacking. Relevant to deceased-donor split liver transplant and living-donor liver transplant in adult recipients, in this study, we present our initial characterization of SFSG model using monosegments of a discarded human donor liver.

Portal vein ligation and in situ liver splitting in metastatic liver cancer

The most serious complication after major liver resection is liver failure. Depending on preoperative liver function, a future liver remnant of 25%-40% is considered sufficient to avoid postoperative liver failure. A new technique known as portal vein ligation combined with in situ splitting has been developed to obtain rapid liver hypertrophy. Herein, we present a case where we performed portal vein ligation combined with in situ splitting. A 37-year-old male patient with a diagnosis of sigmoid adenocarcinoma and liver metastasis underwent anterior resection because of an obstructing sigmoid tumor and received palliative chemotherapy. After chemotherapy, abdominal computed tomography revealed a lesion, 50 mm in diameter, localized between segments 5-8 of the liver on the bifurcation of the anteroposterior segmental branch of the right portal vein. Computed tomography volumetric assessments of the liver were performed in the preoperative period, and it was found that the remnant left liver volume was less than 25%. In the first stage, portal vein ligation and in situ splitting of the liver parenchyma were performed. On the second and sixth postoperative days, computed tomography revealed hypertrophy of the left liver lobe. On the sixth day, a right hepatectomy was performed. Portal vein ligation combined with in situ splitting has been used by surgeons worldwide to obtain rapid and adequate liver hypertrophy. This new approach yields hope for patients with locally advanced liver tumors and may increase the number of curative resections for primary or metastatic liver tumors.

Conversion therapy and suitable timing for subsequent salvage surgery for initially unresectable hepatocellular carcinoma: What is new?

AIM

To review the conversion therapy for initially unresectable hepatocellular carcinoma (HCC) patients and the suitable timing for subsequent salvage surgery.

METHODS

A PubMed search was undertaken from 1987 to 2017 to identify articles using the keywords including “unresectable” “hepatocellular carcinoma”, ”hepatectomy”, ”conversion therapy”, “resection”, “salvage surgery” and “downstaging”. Additional studies were investigated through a manual search of the references from the articles. The exclusion criteria were duplicates, case reports, case series, videos, contents unrelated to the topic, comments, and editorial essays. The main and widely used conversion therapies and the suitable timing for subsequent salvage surgery were discussed in detail. Two members of our group independently performed the literature search and data extraction.

RESULTS

Liver volume measurements [future liver remnant (FLR)/total liver volume or residual liver volume/bodyweight ratio] and function tests (scoring systems and liver stiffness) were often performed in order to justify whether patients were suitable candidates for surgery. Successful conversion therapy was usually defined as downstaging the tumor, increasing FLR and providing subsequent salvage surgery, without increasing complications, morbidity or mortality. The requirements for performing salvage surgery after transcatheter arterial chemoembolization were the achievement of a partial remission in radiology, the disappearance of the portal vein thrombosis, and the lack of extrahepatic metastasis. Patients with a standardized FLR (sFLR) > 20% were good candidates for surgery after portal vein embolization, while other predictive parameters like growth rate, kinetic growth rate were treated as an effective supplementary. There was probably not enough evidence to provide a standard operation time after associating liver partition and portal vein ligation for staged hepatectomy or yttrium-90 microsphere radioembolization. The indications of any combinations of conversion therapies and the subsequent salvage surgery time still need to be carefully and comprehensively evaluated.

CONCLUSION

Conversion therapy is recommended for the treatment of initially unresectable HCC, and the suitable subsequent salvage surgery time should be reappraised and is closely related to its previous therapeutic effect.

Portal venous pressure and proper graft function in living donor liver transplants in 69 patients from an Egyptian center

BACKGROUND

Several studies have defined the optimal portal pressure suitable for adequate graft renewal in liver transplantation (LT) but none have studied an Egyptian population to our knowledge.

OBJECTIVES

Determine the level of portal venous pressure (PVP) for adequate graft function, and study the effect of PVP modulation on the outcome of LT in an Egyptian population.

DESIGN

Cross-sectional, prospectively collected data.

SETTING

Liver transplantation unit.

PATIENTS AND METHODS

The study included adult cirrhotic pa.tients who underwent right lobe liver donor living transplantation (LDLT) at our transplantation center. Intraoperative Doppler was performed on all LDLT patients. Two PVP measurements were obtained during the recipient operation: before PV clamping and after graft re-perfusion. These PVP measurements were correlated with the results of intraoperative and postoperative Doppler findings and graft function. Mortality in the early postoperative period ( less than 1 month) and development of small-for-size syndrome (SFSS) were recorded.

MAIN OUTCOME MEASURES

PVP, graft injury, and the effect of PVP modulation on the outcome of LT were the primary outcome measures. Secondary outcome measures were to correlate PVP to portal vein hemodynamics and intraoperative mean hepatic artery, peak systolic velocity, and also to correlate PVP with the postoperative graft function and mean postoperative platelet count.

SAMPLE SIZE AND CHARACTERISTICS

69 adult patients with end-stage liver disease.

RESULTS

Post-reperfusion PVP was lower than pre-clamping PVP. The mean pre-clamping and post-reperfusion values were higher in patients who experienced early mortality and in patients with smaller grafts. A PVP greater than 16.5 mm Hg at the end of the operation predicted the development of SFSS (sensitivity=91.7% and specificity=50.5%). Cases of high PVP that were modulated to a lower level had a smooth and uneventful postoperative outcome.

CONCLUSION

PVP is a significant hemodynamic factor that influences the functional status of the transplanted liver, including the development of SFSS, in the Egyptian population. PVP modulation may improve the outcome of LDLT.

LIMITATIONS

Further study with a larger sample is needed to confirm these results.

CONFLICT OF INTEREST

None.

Perioperative von Willebrand factor dynamics are associated with liver regeneration and predict outcome after liver resection

von Willebrand Factor (vWF) was found to mediate platelet influx during the early phase of liver regeneration in mice. Furthermore, increased vWF-antigen (vWF-Ag) levels were shown to be predictive for outcome of patients with chronic liver disease. Accordingly, we aimed to assess the relevance of perioperative vWF-Ag dynamics in terms of liver regeneration and clinical outcome in patients undergoing liver resection (LR). Accordingly, we observed that vWF-Ag and its activity-estimated by ristocetin cofactor measurement-increased immediately after induction of liver regeneration and was associated with platelet accumulation within the liver. However, a significant vWF-Ag burst was only observed in patients with unaffected postoperative liver regeneration. E-selectin, as an established marker for endothelial cell activation, was found to correlate with vWF-Ag in the liver vein after induction of liver regeneration (R = 0.535, P = 0.022). Preoperative vWF-Ag levels significantly predicted postoperative liver dysfunction (LD; N = 95; area under the curve, 0.725; P = 0.009). Furthermore, a cutoff of vWF-Ag ≥182% was defined to identify patients with a higher risk for postoperative LD or morbidity. This was confirmed within an independent mulitcenter validation cohort (N = 133). Ultimately, multivariable analysis revealed that vWF-Ag was an independent predictor of postoperative LD and morbidity.

CONCLUSION

Within this study, we were able to provide evidence that an initial vWF burst is required to allow for adequate platelet accumulation and concomitant liver regeneration post-LR and might be abolished as a consequence of intrahepatic endothelial cell dysfunction. We were further able to reveal and validate the potential of preoperative vWF-antigen levels to predict poor postoperative outcome in patients undergoing LR. Despite the pathophysiological relevance of our findings, vWF-Ag seems to be a valuable tool for preoperative risk assessment in patients undergoing LR. (Hepatology 2018;67:1516-1530).

The molecular adsorbent recirculating system in posthepatectomy liver failure: Results from a prospective phase I study

Posthepatectomy liver failure (PHLF) represents the single most important cause of postoperative mortality after major liver resection, yet no effective treatment option is available. Extracorporeal liver support devices might be helpful, but systematic studies are lacking. Accordingly, we aimed to assess the safety and feasibility of the Molecular Adsorbent Recirculating System (MARS) in patients with PHLF. Between December 2012 and May 2015, a total of 206 patients underwent major or extended hepatectomy, and 10 consecutive patients with PHLF (according to the Balzan 50:50 criteria) were enrolled into the study. MARS treatment was initiated on postoperative day 5-7, and five to seven consecutive treatment sessions were completed for each patient. In total, 59 MARS cycles were implemented, and MARS was initiated and completed without major complications in any patient. However, 1 patient developed an immense asymptomatic hyperbilirubinemia (without encephalopathy), 1 had repeated clotting problems in the MARS filter, and 2 patients experienced access problems with the central venous line. Otherwise, no adverse events were observed. In 9 patients, the bilirubin level and international normalized ratio decreased significantly (P < 0.05) during MARS treatment. The 60- and 90-day mortality was 0% and 10%, respectively. Among the 9 survivors, 4 still had liver dysfunction at 90 days postoperatively. Five patients were alive 1 year postoperatively without any signs of liver dysfunction or disease recurrence. Conclusion: The use of MARS in PHLF is feasible and safe and improves liver function in patients with PHLF. In the present study, 60- and 90-day mortality rates were unexpectedly low compared to a historical control group. The impact of MARS treatment on mortality in PHLF should be further evaluated in a randomized controlled clinical trial. (Hepatology Communications 2018;2:445-454).

Model and methods to assess hepatic function from indocyanine green fluorescence dynamical measurements of liver tissue

The indocyanine green (ICG) clearance, presented as plasma disappearance rate is, presently, a reliable method to estimate the hepatic "function". However, this technique is not instantaneously available and thus cannot been used intra-operatively (during liver surgery). Near-infrared spectroscopy enables to assess hepatic ICG concentration over time in the liver tissue. This article proposes to extract more information from the liver intensity dynamics by interpreting it through a dedicated pharmacokinetics model. In order to account for the different exchanges between the liver tissues, the proposed model includes three compartments for the liver model (sinusoids, hepatocytes and bile canaliculi). The model output dependency to parameters is studied with sensitivity analysis and solving an inverse problem on synthetic data. The estimation of model parameters is then performed with in-vivo measurements in rabbits (El-Desoky et al. 1999). Parameters for different liver states are estimated, and their link with liver function is investigated. A non-linear (Michaelis-Menten type) excretion rate from the hepatocytes to the bile canaliculi was necessary to reproduce the measurements for different liver conditions. In case of bile duct ligation, the model suggests that this rate is reduced, and that the ICG is stored in the hepatocytes. Moreover, the level of ICG remains high in the blood following the ligation of the bile duct. The percentage of retention of indocyanine green in blood, which is a common test for hepatic function estimation, is also investigated with the model. The impact of bile duct ligation and reduced liver inflow on the percentage of ICG retention in blood is studied. The estimation of the pharmacokinetics model parameters may lead to an evaluation of different liver functions.

Experimental evaluation of liver regeneration patterns and liver function following ALPPS

Background

The underlying mechanism of liver regeneration after Associating Liver Partition and Portal vein ligation (PVL) for Staged hepatectomy (ALPPS) is still unclear. The aim of this study was to evaluate the relationship between future liver remnant (FLR) volume, liver regeneration characteristics and restoration of function in an experimental model of ALPPS.

Methods

An ALPPS model in rats was developed with selective PVL, parenchymal transection and partial hepatectomy (step 1), followed by resection of the liver (step 2). Three different ALPPS groups with FLR sizes of 30, 20 and 10 per cent of total liver volume were compared with sham‐operated controls and animals undergoing resection of left lateral lobe and 90 per cent PVL with respect to morbidity, mortality, liver regeneration and function.

Results

Three of 15 animals that had ALPPS with 10 per cent FLR (ALPPS10) died after step 1. Ascites developed in two of five rats that had ALPPS with 20 per cent FLR and in three of four animals in the ALPPS10 group after step 2. Although the relative increments in FLR size and growth rates were highest in the ALPPS groups, small FLR size was associated with a sustained increase in levels of serum aminotransferases and bilirubin, a lower albumin concentration, severe sinusoidal injury, increased expression of proliferation markers and increased activation of hepatic progenitor cells after step 2.

Conclusion

There is discordance between FLR volume increase and functional restoration after the ALPPS procedure.

Liver transplantation using the otherwise-discarded partial liver resection graft with hepatic benign tumor: Analysis of a preliminary experience on 15 consecutive cases

RATIONALE

The shortage of available donor organs limits the development of liver transplantation. This case-serial study presents a novel way to expand the donor pool by using the other-wise discarded partial liver resection graft with hepatic benign tumor.

PATIENT CONCERNS

From 2012 to 2016, 15 patients with hepatic lesions were admitted to our hospital. 12 patients suffered from right epigastric discomfort and 3 patients worried about uncertain diagnosis.

INTERVENTIONS

Regular hepatic lobectomy was performed for all patients and after back-table management the resected partial liver grafts were used for patients with end-stage liver disease for liver transplantation.

OUTCOMES

All patients had improved liver function within 1 week of transplantation. Patients had no serious small-for-size syndrome despite graft-to-recipient weight ratio less than 0.8%. Back-table hepatic venous reconstruction with prosthetic vascular grafts was performed without serious early complications, and late thrombosis in vessel graft did not affect liver function. Postoperative computed tomography scans demonstrated a remarkable growth in graft volume and a continuous decrease in hemangioma in recipients using the grafts with hemangioma. One patient died from pulmonary embolism on day 7 after transplant, and the rest of 14 recipients had been surviving well, especially recipient 1 for more than 4 years, although 3 recipients had tumor recurrence and had been treated with sorafenib.

DIAGNOSES

The postoperative pathological diagnosis reported cavernous hemangioma (n = 11), perivascular epithelioid cell tumor (n = 2), inflammatory pseudotumor for (n = 1), and focal nodular hyperplasia (n = 1).

LESSONS

The partial liver grafts with hepatic benign tumors are safe for liver transplantation. In addition, prosthetic vascular grafts can be used for hepatic venous outflow reconstruction, especially in right lobe liver transplantation.

Outcomes of right-lobe and left-lobe living-donor liver transplantations using small-for-size grafts

AIM

To analyze the outcomes of living-donor liver transplantation (LDLT) using left-lobe (LL) or right-lobe (RL) small-for-size (SFS) grafts.

METHODS

Prospectively collected data of adult patients who underwent LDLT at our hospital in the period from January 2003 to December 2013 were reviewed. The patients were divided into the RL-LDLT group and the LL-LDLT group. The two groups were compared in terms of short- and long-term outcomes, including incidence of postoperative complication, graft function, graft survival, and patient survival. A SFS graft was defined as a graft with a ratio of graft weight (GW) to recipient standard liver volume (RSLV) (GW/RSLV) of < 50%. The Urata formula was used to estimate RSLV.

RESULTS

Totally 218 patients were included for analysis, with 199 patients in the RL-LDLT group and 19 patients in the LL-LDLT group. The two groups were similar in terms of age (median, 53 years in the RL-LDLT group and 52 years in the LL-LDLT group, P = 0.997) but had significantly different ratios of men to women (165:34 in the RL-LDLT group and 8:11 in the LL-LDLT group, P < 0.0001). The two groups were also significantly different in GW (P < 0.0001), GW/RSLV (P < 0.0001), and graft cold ischemic time (P = 0.007). When it comes to postoperative complication, the groups were comparable (P = 0.105). Five patients died in hospital, 4 (2%) in the RL-LDLT group and 1 (5.3%) in the LL-LDLT group (P = 0.918). There were 38 graft losses, 33 (16.6%) in the RL-LDLT group and 5 (26.3%) in the LL-LDLT group (P = 0.452). The 5-year graft survival rate was significantly better in the RL-LDLT group (95.2% vs 89.5%, P = 0.049). The two groups had similar 5-year patient survival rates (RL-LDLT: 86.8%, LL-LDLT: 89.5%, P = 0.476).

CONCLUSION

The use of SFS graft in LDLT requires careful tailor-made surgical planning and meticulous operation. LL-LDLT can be a good alternative to RL-LDLT with similar recipient outcomes but a lower donor risk. Further research into different patient conditions is needed in order to validate the use of LL graft.

Associating liver partition and portal vein ligation for staged hepatectomy: A surgical technique for liver resections

Background:

Associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) is a novel surgical technique liver resection in traditionally nonresectable primary intrahepatic tumors or colorectal liver metastases.

Materials and Methods:

From June 2013 to March 2014, patients with primary tumor of liver or colorectal tumors with liver metastasis were selected to evaluate whether they met the initial criteria for ALPPS procedure.

Results:

Nine patients enrolled in the study with primary diagnoses of colon and rectosigmoid cancer, carcinoid tumor, gastrointestinal stromal tumor of small intestine, hepatocellular carcinoma, and pancreatic neuroendocrine tumor (PNET). Four candidates excluded from the study prior or during the first step operation due to fatty liver, hepatic fibrosis, peritoneal seeding, and multiple small intestine metastases. Five patients underwent two stages of ALPPS with the interval of about 1 week. Liver hypertrophy was 100% among our candidates after the initial step. One postoperative death happened because of massive pulmonary thromboembolism Recurrence of liver metastasis was seen in one patient. Hepatic failure Class B and A were observed in two patients which did not progress during follow-up period. One patient developed an enterocutaneous fistula.

Discussion:

We recommend to use 2 organ bags, one for wrapping right lobe and the other one for covering visceral organs and also do liver biopsy in suspicious cases of damaged liver parenchyma and laparoscopic exploration of abdomen for seeding and multiple metastases prior to laparotomy.

Conclusion:

As the procedure has not been well established and verified by oncologists yet, further studies are required to define the exact indications of ALPPS.

Epidemiology and risk factors for infection after living donor liver transplantation

The epidemiology of infections after living donor liver transplantation (LDLT) is limited. We aimed to study the epidemiology and risk factors of infections after LDLT. The medical records of 223 adult patients who underwent LDLT from January 1, 2000 to August 31, 2015 were reviewed for all infections occurring up to 1 year. We estimated the cumulative incidence of infection using the Kaplan-Meier product limit method. Risk factors were analyzed with time-dependent Cox regression modeling. The majority of patients were Caucasian (94.6%) and male (64.6%), and the median age at transplantation was 55 years. The most common indication for transplantation was primary sclerosing cholangitis (37.7%). A total of 122 patients developed an infection during the follow-up period (1-year cumulative event rate of 56%), with the majority (66%) of these occurring within 30 days after transplantation. Enterococcus sp. was the most frequent pathogen identified. Multivariate analysis showed that increased Model for End-Stage Liver Disease (MELD) score (per 10-point change: hazard ratio [HR], 1.59), history of recurrent infections prior to transplant (HR, 2.01), Roux-en-Y anastomosis (HR, 2.37), increased log-number of packed red blood cell transfusions (HR, 1.39), and biliary complications (HR, 4.26) were independently associated with a higher risk of infection. Infections occur commonly after LDLT, with most infections occurring early and being related to the hepatobiliary system. Higher MELD scores, the type of biliary anastomosis, presence of biliary complications, and prior pretransplant infections are independently associated with a higher risk for infections. Liver Transplantation 23 465-477 2017 AASLD.

Management of liver cancer. The Surgeon's point of view

During the last twenty years, a huge progress has been achieved in the treatment of liver cancer and recent strategies include interventional radiology, chemotherapy regimens and surgery. Meanwhile, Stereotactic Body Radiation Therapy (SRBT) has developed in the treatment of all organs with millimetre accuracy, very few side effects and a high control rate. So, SRBT has become a therapeutic weapon in his own right in liver tumour treatment. Many publications have reported encouraging results in colorectal liver metastasis, hepatocellular carcinoma on cirrhosis and peripheric cholangiocarcinoma. It is important that radiation therapists involve systematic multidisciplinary "liver tumour" meetings to discuss therapeutic indications and initiate treatments quickly.

Establishing a Porcine Model of Small for Size Syndrome following Liver Resection

BACKGROUND

Small for size syndrome (SFSS) is responsible for a high proportion of mortalities and morbidities following extended liver resection.

AIM

The aim of this study was to establish a porcine model of SFSS.

METHODS

Twenty-four Landrace pigs underwent liver resection with a remnant liver volume of 50% (group A, n = 8), 25% (group B, n = 8), and 15% (group C, n = 8). After resection, the animals were followed up for 8 days and clinical, laboratory, and histopathological outcomes were evaluated.

RESULTS

The survival rate was significantly lower in group C compared with the other groups (p < 0.001). The international normalized ratio, bilirubin, aspartate transaminase, alanine transaminase, and alkaline phosphatase levels increased shortly after surgery in groups B and C, but no change was observed in group A (p < 0.05 for all analyses). The histopathological findings in group A were mainly mild mitoses, in group B severe mitoses and hepatocyte ballooning, moderate congestion, and hemorrhage, along with mild necrosis, and in group C extended tissue damage with severe necrosis, hemorrhage, and congestion.

CONCLUSIONS

Combination of clinical, laboratory, and histopathological evaluations is needed to confirm the diagnosis of SFSS. 75% liver resection in porcine model results in SFSS. 85% liver resection causes irreversible liver failure.

Perioperative Non-Invasive Indocyanine Green-Clearance Testing to Predict Postoperative Outcome after Liver Resection

Background

Postoperative liver dysfunction may lead to morbidity and mortality after liver resection. Preoperative liver function assessment is critical to identify preexisting liver dysfunction in patients prior to resection. The aim of this study was to evaluate the predictive potential of perioperative indocyanine green (ICG)-clearance testing to prevent postoperative liver dysfunction and morbidity using standardized outcome parameters in a routine Western-clinical-setting.

Study Design

137 patients undergoing partial hepatectomy between 2011 and 2013, at the general hospital of Vienna, were included. ICG-clearance was recorded one day prior to surgery as well as on the first and fifth postoperative day. Postoperative liver dysfunction was defined according to the International Study Group of Liver Surgery and evaluation of morbidity was based on the Dindo-Clavien classification. Statistical analyses were based on non-parametric tests.

Results

Preoperative reduced ICG—plasma disappearance rate (PDR) as well as increased ICG—retention rate at 15 min (R15) were able to significantly predict postoperative liver dysfunction (Area under the curve = PDR: 0.716, P = 0.018; R15: 0.719, P = 0.016). Furthermore, PDR <17%/min. or R15 >8%, were able to accurately predict postoperative complications prior to surgery. In addition to this, ICG-clearance on postoperative day 1 comparably predicted postoperative liver dysfunction (Area under the curve = PDR: 0.895; R15: 0.893; both P <0.001), specifically, PDR <10%/min or R15 >20% on postoperative day 1 predicted poor postoperative outcome.

Conclusion

PDR and R15 may represent useful parameters to distinguish preoperative high and low risk patients in a Western collective as well as on postoperative day 1, to identify patients who require closer monitoring for potential complications.

In-vivo organ engineering: Perfusion of hepatocytes in a single liver lobe scaffold of living rats

Organ decellularization is emerging as a promising regenerative medicine approach as it is able to provide an acellular, three-dimensional biological scaffold material that can be seeded with living cells for organ reengineering. However this application is currently limited to donor-derived decellularized organs for reengineering in vitro and no study has been conducted for re-engineering the decellularized organ in vivo. We developed a novel technique of a single liver lobe decellularization in vivo in live animals. Using a surgical method to generate a by-pass circulation through the portal vein and infra-hepatic vena cava with a perfusion chamber system, we decellularized the single liver lobe and recellularized it with allogenic primary hepatocytes. Our results showed that the decellularization process in vivo can preserve the vascular structural network and functional characteristics of the native liver lobe. It allows for efficient recellularization of the decellularized liver lobe matrix with allogenic primary hepatocytes. Upon the re-establishment of blood circulation, the recellularized liver lobe is able to gain the function and the allogenic hepatocytes are able to secret albumin. Our findings provide a proof of principle for the in vivo reengineering of liver.

Parenchymal-sparing liver surgery in patients with colorectal carcinoma liver metastases

Liver resection is the treatment of choice for patients with colorectal liver metastases (CLM). However, major resections are often required to achieve R0 resection, which are associated with substantial rates of morbidity and mortality. Maximizing the amount of residual liver gained increasing significance in modern liver surgery due to the high incidence of chemotherapy-associated parenchymal injury. This fact, along with the progressive expansion of resectability criteria, has led to the development of a surgical philosophy known as "parenchymal-sparing liver surgery" (PSLS). This philosophy includes a variety of resection strategies, either performed alone or in combination with ablative therapies. A profound knowledge of liver anatomy and expert intraoperative ultrasound skills are required to perform PSLS appropriately and safely. There is a clear trend toward PSLS in hepatobiliary centers worldwide as current evidence indicates that tumor biology is the most important predictor of intrahepatic recurrence and survival, rather than the extent of a negative resection margin. Tumor removal avoiding the unnecessary sacrifice of functional parenchyma has been associated with less surgical stress, fewer postoperative complications, uncompromised cancer-related outcomes and higher feasibility of future resections. The increasing evidence supporting PSLS prompts its consideration as the gold-standard surgical approach for CLM.

Small for Size and Flow (SFSF) syndrome: An alternative description for posthepatectomy liver failure

Small for Size Syndrome (SFSS) syndrome is a recognizable clinical syndrome occurring in the presence of a reduced mass of liver, which is insufficient to maintain normal liver function. A definition has yet to be fully clarified, but it is a common clinical syndrome following partial liver transplantation and extended hepatectomy, which is characterized by postoperative liver dysfunction with prolonged cholestasis and coagulopathy, portal hypertension, and ascites. So far, this syndrome has been discussed with focus on the remnant size of the liver after partial liver transplantation or extended hepatectomy. However, the current viewpoints believe that the excessive flow of portal vein for the volume of the liver parenchyma leads to over-pressure, sinusoidal endothelial damages and haemorrhage. The new hypothesis declares that in both extended hepatectomy and partial liver transplantation, progression of Small for Size Syndrome is not determined only by the "size" of the liver graft or remnant, but by the hemodynamic parameters of the hepatic circulation, especially portal vein flow. Therefore, we suggest the term "Small for Size and Flow (SFSF)" for this syndrome. We believe that it is important for liver surgeons to know the pathogenesis and manifestation of this syndrome to react early enough preventing non-reversible tissue damages.

Role of microRNA in liver regeneration

BACKGROUND

Liver regeneration is a complex process. microRNAs (miRNAs) are short, single-stranded RNAs that modify gene expression at the post-transcriptional level. Recent investigations have revealed that miRNAs are closely linked to liver regeneration.

DATA SOURCES

All included studies were obtained from PubMed, Embase, the ScienceDirect databases and Web of Science, with no limitation on publication year. Only studies published in English were considered.

RESULTS

We grouped studies that involved miRNA and liver regeneration into two groups: miRNAs as promoters and as inhibitors of liver regeneration. We summarized the relevant miRNAs separately from the related pathways.

CONCLUSIONS

Blocking or stimulating the pathways of miRNAs in liver regeneration may be novel therapeutic strategies in future regeneration-related liver managements. We may discover additional chemotherapy targets of miRNA.

Serial volumetric assessment of large for size liver grafts after whole cadaveric liver transplant in adults: do large liver grafts shrink in size?

BACKGROUND

After whole graft orthotopic liver transplantation (OLT), adaptation of the large grafts' volume to recipient weight is widely accepted despite the paucity of evidence on this subject.

METHODS

Thirty nine patients with GRWR > 2.5% were included in this study and subsequently divided into two groups with 3 ≥ GRWR > 3%. Patients had CT scans at three predetermined time points after OLT used for measuring the liver volume. The objective of this study is to evaluate the volumetric changes of whole large liver grafts after adult OLT.

RESULTS

At LT, the mean graft recipient body weight ratio (GRWR) was 3.1 ± 0.4%. The mean liver weight was 1881 ± 68 g at LT, 2014 ± 99 ml at one week, 1725 ± 126 ml at 3 months, and 1632 ± 117 (ml) at >6 months. There is an initial increase at 1 week after LT and a subsequent decrease of liver volume on later measurements. None of the late volume measurements were significantly different from the initial graft volume at liver transplant in pair wise comparisons ANOVA repeated measures (p > 0.05). Similarly, the mean GRWR did not change significantly between the initial calculation at transplantation date and the subsequent measurements during the different study time points (F = 0.04, p = 0.96) with a mean of 3.1% (95% CI = 2.2-4.2). AUC ROC discriminated a cutoff of 3% for the initial GRWR above which grafts tend to decrease in size over time (c statistics = 0.74, p = 0.036). In a Clustered ANOVA repeated measures, there was no significant difference in the changes of liver volume between both groups. However, patients with GRWR > 3 showed a trend towards a latent reduction in volume over the tracing period. There was a tendency, but none significant; towards a higher bilirubin, AST, ALT levels over the first postoperative days in recipients with GRWR > 3.

CONCLUSION

Large grafts do not significantly decrease in size. Nonetheless, grafts weighing >3% of the GRWR show a different trend towards decrease in size over time.