Lower limit of the graft-to-recipient weight ratio can be safely reduced to 0.6% in adult-to-adult living donor liver transplantation in combination with portal pressure control. Transplant Proc. 2011;43:2391-2393. [PMID: 21839274 DOI: 10.1016/j.transproceed.2011.05.037]

Post Living Donor Liver Transplantation Small-for-size Syndrome: Definitions, Timelines, Biochemical, and Clinical Factors for Diagnosis: Guidelines From the ILTS-iLDLT-LTSI Consensus Conference

BACKGROUND

When a partial liver graft is unable to meet the demands of the recipient, a clinical phenomenon, small-for-size syndrome (SFSS), may ensue. Clear definition, diagnosis, and management are needed to optimize transplant outcomes.

METHODS

A Consensus Scientific committee (106 members from 21 countries) performed an extensive literature review on specific aspects of SFSS, recommendations underwent blinded review by an independent panel, and discussion/voting on the recommendations occurred at the Consensus Conference.

RESULTS

The ideal graft-to-recipient weight ratio of ≥0.8% (or graft volume standard liver volume ratio of ≥40%) is recommended. It is also recommended to measure portal pressure or portal blood flow during living donor liver transplantation and maintain a postreperfusion portal pressure of <15 mm Hg and/or portal blood flow of <250 mL/min/100 g graft weight to optimize outcomes. The typical time point to diagnose SFSS is the postoperative day 7 to facilitate treatment and intervention. An objective 3-grade stratification of severity for protocolized management of SFSS is proposed.

CONCLUSIONS

The proposed grading system based on clinical and biochemical factors will help clinicians in the early identification of patients at risk of developing SFSS and institute timely therapeutic measures. The validity of this newly created grading system should be evaluated in future prospective studies.

Preventing Small-for-size Syndrome in Living Donor Liver Transplantation: Guidelines From the ILTS-iLDLT-LTSI Consensus Conference

Small-for-size syndrome (SFSS) is a well-recognized complication following liver transplantation (LT), with up to 20% developing this following living donor LT (LDLT). Preventing SFSS involves consideration of factors before the surgical procedure, including donor and recipient selection, and factors during the surgical procedure, including adequate outflow reconstruction, graft portal inflow modulation, and management of portosystemic shunts. International Liver Transplantation Society, International Living Donor Liver Transplantation Group, and Liver Transplant Society of India Consensus Conference was convened in January 2023 to develop recommendations for the prediction and management of SFSS in LDLT. The format of the conference was based on the Grading of Recommendations, Assessment, Development, and Evaluation system. International experts in this field were allocated to 4 working groups (diagnosis, prevention, anesthesia, and critical care considerations, and management of established SFSS). The working groups prepared evidence-based recommendations to answer-specific questions considering the currently available literature. The working group members, independent panel, and conference attendees served as jury to edit and confirm the final recommendations presented at the end of the conference by each working group separately. This report presents the final statements and evidence-based recommendations provided by working group 2 that can be implemented to prevent SFSS in LDLT patients.

Early allograft dysfunction after living donor liver transplantation-current concepts and future directions

Early allograft dysfunction (EAD) after liver transplantation is a significant clinical problem that negatively impacts graft and patient outcomes. The rising incidence of EAD and what it means concerning living donor liver transplantation (LDLT) is an area of great interest. However, EAD after LDLT is a complex research topic yet to be reviewed comprehensively. Most of the literature on EAD is based on experience in deceased donor liver transplantation, and limited information is available in the context of LDLT. Thus, in this review, we present an overview of EAD after LDLT and have attempted to present balanced points of view on all its aspects, such as definitions, pathogenesis, risk factors, predictive markers, and management. The review aims to broadly overview the nature and extent of ongoing research evidence on this complex topic and inform practice in the field by identifying key concepts and knowledge gaps and highlighting areas that require further inquiry.

The short- and long-term outcomes in living-donor liver transplantation using small-for-size graft: A systematic review and meta-analysis

BACKGROUND

A standard graft-to-recipient weight ratio (GRWR) ≥0.8% is widely accepted in living-donor liver transplantation (LDLT); however, the potential donor pool is expanded to patients adopting small-for-size graft (SFSGs) with GRWR <0.8%. This study aimed to investigate the effect of SFSG on short- and long-term outcomes following LDLT.

METHODS

Electronic databases were searched from January 1995 to January 2022 for studies comparing short- or long-term outcomes between patients with SFSG (GRWR <0.8%, SFSG group) and sufficient volume graft (GRWR ≥0.8%, non-SFSG group). The primary outcomes were one-, three-, and five-year overall survival (OS) and graft survival (GS), while the secondary outcome was postoperative complications.

RESULTS

Twenty-four studies comprising 7996 patients were included. In terms of OS, SFSG group had poor three-year OS (HR: 1.48, 95% CI [1.01, 2.15], p = 0.04), but there were no significant differences between two groups in one-year OS (HR: 1.50, 95% CI [0.98, 2.29], p = 0.06) and five-year OS (HR: 1.40, 95% CI [0.95, 2.08], p = 0.02). In GS, there were no significant differences in one-year (HR 1.31, 95% CI [1.00, 1.72], p = 0.05), three-year (HR 1.33, 95% CI [0.97, 1.82], p = 0.07), and five-year GS (HR 1.17, 95% CI [0.95, 1.44], p = 0.13). The SFSG group had comparable postoperative complications, except for a high incidence of vascular complications and small-for-size syndromes.

CONCLUSIONS

Expanding the potential donor pool in LDLT to SFSG with GRWR <0.8% can be acceptable in terms of comparable long-term OS and GS, despite the risk for vascular complications and small-for-size syndrome.

The role of graft to recipient weight ratio on enhanced recovery of the recipient after living donor liver transplantation - A systematic review of the literature and expert panel recommendations

BACKGROUND

There continues to be debate about the lower limit of graft-to-recipient weight ratio (GRWR) for living donor liver transplant (LDLT).

OBJECTIVES

To identify the lower limit of GRWR compatible with enhanced recovery after living donor liver transplant and to provide international expert panel recommendations.

DATA SOURCES

Ovid MEDLINE, Embase, Scopus, Google Scholar, and Cochrane Central.

METHODS

Systematic review following PRISMA guidelines and recommendations using the GRADE approach derived from an international expert panel. Studies assessing how GRWR affects recipient outcomes such as small for size syndrome, other complications, patient and graft survival, and length of stay were included.

PROTOCOL REGISTRATION

CRD42021260794.

RESULTS

Twenty articles were included in the qualitative synthesis, and all were retrospective observational studies. There was heterogeneity in the definition of study cohorts and key outcome measures such as small-for-size syndrome. Most studies lacked risk adjustment given limited single-center sample size. GRWR of ≥ .8% is associated with enhanced recovery. Recipients of grafts with GRWR < .8%, however, were found to have similar outcomes as those with ≥ .8% when appropriate consideration is made for portal flow modulation and recipient illness severity.

CONCLUSIONS

GRWR ≥ .8% is often compatible with enhanced recovery, but grafts < .8% can be used in selected LDLT recipients with optimal donor-recipient selection, surgical technique, and perioperative management (Quality of Evidence; Low | Grade of Recommendation; Strong).

Shulan Estimation Model: A New Formula for Estimation of Standard Liver Volume In Chinese Adults

BACKGROUND

To establish a new and accurate model for standard liver volume (SLV) estimation and graft size prediction in liver transplantation for Chinese adults.

METHODS

In this study, the data of morphologic indices and liver volume (LV) were retrospectively obtained on 507 cadaveric liver transplantation donors between June 2017 and September 2020 in Shulan (Hangzhou) Hospital. Linear regression analysis was performed to evaluate the impact of each parameter and develop a new SLV formula. The new formula was then validated prospectively on 97 donors between October 2020 and June 2021, and the prediction accuracy was compared with previous formulas.

RESULTS

The average LV in all subjects was 1445.68 ± 309.94 mL. Body weight (BW) showing the strongest correlation (r = 0.453, P < .001). By stepwise multiple linear regression analysis, BW and age were the only 2 independent correlation factors for LV. Shulan estimation model derived: SLV (mL) = 13.266 × BW (kg) - 4.693 × age + 797.16 (R2 = 0.236, P < .001). In the validation cohort, our new model achieved no significant differences between the estimated SLV and the actual LV (P > .05), and showed the lowest mean percentage error of 0.33%. The proportions of estimated SLV within the actual LV ± 20%, ± 15%, and ± 10% percentage errors were 69.1%, 55.7%, and 40.2%, respectively.

DISCUSSION

The Shulan SLV estimation model predicted LV more accurately than previous formulas on Chinese adults, which could serve as a simple screening tool during the initial assessment of graft volume for potential donors.

Small-For-Size Syndrome and Graft Inflow Modulation Techniques in Liver Transplantation

BACKGROUND

Partial liver transplantation has recently been proposed to alleviate organ shortages. However, transplantation of a small-for-size graft is associated with an increased risk of posttransplant hepatic dysfunction, commonly referred to as small-for-size syndrome (SFSS). This review describes the etiology, pathological features, clinical manifestations, and diagnostic criteria of SFSS. Moreover, we summarize strategies to improve graft function, focusing on graft inflow modulation techniques. Finally, unmet needs and future perspectives are discussed.

SUMMARY

In fact, posttransplant SFSS can be attributed to various factors such as preoperative status of the recipients, surgical techniques, donor age, and graft quality, except for graft size. With targeted improvement measures, satisfactory clinical outcomes can be achieved in recipients at increased risk of SFSS. Given the critical role of relative portal hyperperfusion in the pathogenesis of SFSS, various pharmacological and surgical treatments have been established to reduce or partially divert excessive portal inflow, and recipients will benefit from individualized therapeutic regimens after careful evaluation of benefits against potential risks. However, there remain unmet needs for further research into different aspects of SFSS to better understand the correlation between portal hemodynamics and patient outcomes.

KEY MESSAGES

Contemporary transplant surgeons should consider various donor and recipient factors and develop case-specific prevention and treatment strategies to improve graft and recipient survival rates.

Successful living donor liver transplantation with a graft-to-recipient weight ratio of 0.41 without portal flow modulation: A case report

BACKGROUND

There have been numerous efforts to lower the limit of minimum graft size to meet the metabolic demand of recipients in adult-to-adult living donor liver transplantation (LDLT). We experienced a successful case of LDLT using a very-small-for-size graft without portal flow modulation such as splenectomy or portocaval shunt.

CASE SUMMARY

A 49-year-old man (weighing 91 kg) suffering hepatocellular carcinoma accompanied with hepatitis B virus related cirrhosis underwent LDLT. The one and only voluntary donor was his 17-year-old daughter whose body weight was 50 kg with a body mass index (BMI) of 18.3. The procured right liver graft was 411 g with a real graft-to-recipient weight ratio (GRWR) of 0.41%, the smallest to be reported in the literature. Both the recipient and donor had an uneventful recovery and were discharged on days 15 and 8, respectively, with normal liver function. The father and daughter have had no complication so far and are still in good health with normal liver function 81 mo after LDLT.

CONCLUSION

Satisfactory outcomes can be achieved in LDLT with a GRWR as low as 0.41% even without using portal flow modulation in highly selected patients.

Long-term Outcomes of Stent Placement Inside the Bile Duct for Biliary Strictures After Living Donor Liver Transplantation

In living donor liver transplantation (LDLT), anastomotic biliary stricture is a serious and refractory complication. In this study, we reviewed the transition of post-LDLT anastomotic biliary strictures and evaluated long-term outcomes of stent placement inside the bile duct, which is referred to as an "inside-stent." Of 805 consecutive adult LDLT recipients in our institution (2000-2018), we reviewed 639 patients with duct-to-duct biliary reconstruction and analyzed chronological changes of post-LDLT biliary strictures. Moreover, we focused on the year 2006 when various surgical modifications were introduced and compared the details of post-LDLT biliary strictures before and after 2006, especially focusing on the long-term outcome of inside-stent placement. The proportion of left lobe grafts had increased from 1.8% before 2005 to 39.3% after 2006 (P < 0.001) to maximize the living donor safety. Overall, post-LDLT anastomotic biliary strictures occurred in 21.3% of the patients with a median follow-up period of 106.1 months, which was decreased from 32.6% before 2005 to 12.8% after 2006 (P < 0.001). Anastomotic biliary strictures were less frequent in patients with left lobe grafts than with right lobe grafts (9.4% versus 25.4%; P < 0.001). The overall technical success rate of inside-stent placement was 82.4%, with an improvement from 75.3% before 2005 up to 95.7% after 2006 (P < 0.01). Furthermore, the stricture resolution rate remained high at approximately 90% throughout the observation period. Increased use of left lobe grafts with several surgical modifications significantly reduced post-LDLT anastomotic biliary strictures, leading to favorable long-term outcomes of inside-stent placements for this condition.

Is 0.6% Reasonable as the Minimum Requirement of the Graft-to-recipient Weight Ratio Regardless of Lobe Selection in Adult Living-donor Liver Transplantation?

BACKGROUND

Several studies reported favorable outcomes of small-for-size grafts with graft-to-recipient weight ratio (GRWR) <0.8% in living-donor liver transplantation (LDLT). However, their indications should be carefully determined because they must have been indicated for low-risk cases over larger grafts with 0.8% ≤ GRWR. Furthermore, evidence for minimum requirements of GRWR remains inconclusive. We investigated the safety of small-for-size grafts against larger grafts by adjusting for confounding risk factors, and minimum requirement of graft volume in adult LDLT.

METHODS

We enrolled 417 cases of primary adult-to-adult LDLT in our center between 2006 and 2019. The outcomes of small grafts (0.6% ≤ GRWR < 0.8%, n = 113) and large grafts (0.8% ≤ GRWR, n = 289) were mainly compared using a multivariate analysis and Kaplan-Meier estimates.

RESULTS

The multivariate analysis showed that small grafts were not a significant risk factor for overall graft survival (GS). In the Kaplan-Meier analysis, small grafts did not significantly affect overall GS regardless of lobe selection (versus large grafts). However, GRWR < 0.6% was associated with poor overall GS. Although there were no significant differences between the 2 groups, unadjusted Kaplan-Meier curves of small grafts were inferior to those of large grafts in subcohorts with ABO incompatibility, and donor age ≥50 years.

CONCLUSIONS

Similar outcomes were observed for small and large graft use regardless of lobe selection. 0.6% in GRWR was reasonable as the minimum requirement of graft volume in LDLT. However, small grafts should be indicated carefully for high-risk cases.

CT and MR imaging evaluation of living liver donors

Preoperative cross-sectional imaging evaluation of potential living liver donors allows to exclude donors with an increased risk for morbidity and mortality, and to assure that a suitable graft for the recipient can be obtained, minimizing the risk of complications in both the donor and the recipient. CT is routinely performed to delineate the anatomy of the liver, relevant vasculature, and liver volumes in whole right or left lateral segment donation. MR imaging is the gold standard for the assessment of biliary anatomy and allows a better quantification of hepatic steatosis compared to CT. Knowledge of normal and variant vascular and biliary anatomy and their surgical relevance for liver transplantation is of paramount importance for the radiologist. The purpose of this review is to outline the current role of CT and MR imaging in the assessment of hepatic parenchyma, hepatic vascular anatomy, biliary anatomy, and hepatic volumetry in the potential living liver donor with short notes on acquisition protocols and the relevant reportable findings.

Study of factors affecting Small for Size Syndrome Post-Adult living donor liver transplantation

AIM

Recently, increasing evidence showed that small-for-size syndrome (SFSS) is a multifactorial disease which is precipitated by various perioperative factors other than graft size. We conducted the current work to evaluate perioperative effectors, which can increase the risk of SFSS following adult living-donor liver transplantation (LDLT).

METHODS

This is a retrospective study on 110 adult cirrhotic cases (mean age of 48.4 ± 6.9 years old) who underwent adult LDLT. Most cases were males (89%). Cases were categorized into two groups based on the occurrence of SFSS. The groups were compared regarding preoperative (gender, age, comorbidities, baseline investigations), intraoperative (mean blood pressure and glucose; mean operation time; number of packed red cells, plasma, platelets, and cryoprecipitate units; time of cold and warm ischemia, and anhepatic phase; preclamping and post-reperfusion portal pressures), and postoperative factors (relevant investigations, hospital stay).

RESULTS

Postoperatively, 23 patients developed SFSS (20.9%). SFSS group had significantly lower preoperative graft recipient weight ratio (GRWR) (0.76 ± 0.1% versus 1.03 ± 0.15, respectively; p < 0.001), and elevated MELD scores (19 ± 2.1 versus 17.9 ± 4; p = 0.024). Preclamping and post-reperfusion portal pressures of ≥22.5 and 17.5 mmHg, exhibited a sensitivity of 95.7% and 91.3% and specificity of 87.4% and 88.9% respectively, for SFSS prediction.

CONCLUSION

SFSS risk is significantly linked to GRWR, MELD score, and intraoperative portal haemodynamics. Intraoperative portal haemodynamics exhibited good diagnostic accuracy for SFSS prediction and represented promising indicators for the prediction of SFSS.

Association of Graft-to-Recipient Weight Ratio with the Prognosis Following Liver Transplantation: a Meta-analysis

BACKGROUND

Studies indicate that low graft-to-recipient weight ratio (GRWR) affect graft survival in adult-to-adult living donor liver transplantation. However, the potential role of GRWR in the prognosis of patients following living donor liver transplantation according to patient characteristics remains controversial. This study aimed to update the role of GRWR in patients following living donor liver transplantation.

METHODS

PubMed, Embase, and Cochrane Library were comprehensively searched for studies comparing low GRWR (< 0.8%) with normal GRWR (≥ 0.8%) in the prognosis following living donor liver transplantation from inception to March 2019. The 1-, 3-, and 5-year summary survival rates, small-for-size syndrome (SFSS), perioperative mortality, biliary complications, postoperative bleeding, and acute rejection were calculated using the random-effects model.

RESULTS

Eighteen studies comprising 4001 patients were included. Patients with low GRWR were associated with lower 1-year and 3-year survival rates compared to patients with normal GRWR, while no significant difference was found in the association of 5-year survival rate with low and normal GRWRs. Moreover, the risk of SFSS significantly increased in patients with low GRWR. Finally, no significant differences were observed in the association of low and normal GRWRs with the risk of perioperative mortality, biliary complications, postoperative bleeding, and acute rejection.

CONCLUSION

The results of this study indicated that low GRWR was associated with poor prognosis for patients following living donor liver transplantation, especially in terms of 1- and 3-year survival rates and SFSS.

Recent evolution of living donor liver transplantation at Kyoto University: How to achieve a one-year overall survival rate of 99%?

Previously, living donor liver transplantation was considered as a "high-risk, high-return" medical treatment due to the relatively high short-term mortality. It is our task to change "high-risk, high-return" into a "low-risk, high-return" situation. In this review article, the recent evolutions in living donor liver transplantation for both donors and recipients at Kyoto University such as portal vein pressure modulation, hybrid donor operation, and perioperative management considering sarcopenia, focusing on improvement of short-term outcomes are described. Under a paradigm of "marketing and innovation", various innovations and efforts have been made over the last decade aiming at improving the short-term outcomes of both donors and recipients. By doing so, excellent short-term results after living donor liver transplantation have been achieved, along with a potentially epoch-making discoveries.

Small-for-size syndrome in liver transplantation: Definition, pathophysiology and management

BACKGROUND

Since the first success in an adult patient, living donor liver transplantation (LDLT) has become an universally used procedure. Small-for-size syndrome (SFSS) is a well-known complication after partial LT, especially in cases of adult-to-adult LDLT. The definition of SFSS slightly varies among transplant physicians. The use of a partial liver graft has risks of SFSS development. Persistent portal vein (PV) hypertension and PV hyper-perfusion after LT were identified as the main factors. Hence, various approaches were explored to modulate PV flow and decrease PV pressure in order to alleviate this syndrome. Herein, the definition, clinical symptoms, pathophysiology, basic research, as well as preventive and treatment strategies for SFSS are reviewed based on an extensive review of the literature and on our own experiences.

DATA SOURCES

The articles were collected through PubMed using search terms "liver transplantation", "living donor liver transplantation", "living liver donation", "partial graft", "small-for-size graft", "small-for-size syndrome", "graft volume", "remnant liver", "standard liver volume", "graft to recipient body weight ratio", "sarcopenia", "porcine", "swine", and "rat". English publications published before March 31, 2020 were included in this review.

RESULTS

Many transplant surgeons performed PV flow modulation, including portocaval shunt, splenic artery ligation and splenectomy. With these techniques, patient outcome has been improved even when using a "small" graft. Other factors, such as preoperative recipients' nutritional and skeletal muscle status, graft congestion, and donor factors, were also identified as risk factors which all have been addressed using various strategies.

CONCLUSIONS

The surgical approach controlling PV flow and pressure could help to prevent SFSS especially in severely ill recipients. In the absence of efficacious medications to resolve SFSS, conservative treatments, including aggressive fluid balance correction for massive ascites, anti-microbiological therapy to prevent or control sepsis and intensive nutritional therapy, are all required if SFSS could not be prevented.

Post-transplant inflow modulation for early allograft dysfunction after living donor liver transplantation

Background

To treat small-for-size syndrome (SFSS) after living donor liver transplantation (LDLT), many procedures were described for portal flow modulation before, during, or after transplantation. The selection of the procedure as well as the best timing remains controversial.

Case presentation

A 43-year-old female with end-stage liver disease underwent LDLT with extended left with caudate lobe graft from her donor who was her 41-year-old brother (graft volume/standard liver volume (GV/SLV), 35.7%; graft to recipient weight ratio (GRWR), 0.67%). During the surgery, splenectomy could not be performed owing to severe peri-splenic adhesions to avoid the ruined bleedings. The splenic artery ligation was not also completely done because it was dorsal to the pancreas and difficult to be approached. Finally, adequate portal vein (PV) inflow was confirmed after portal venous thrombectomy. As having post-transplant optional procedures that are accessible for PV flow modulation, any other procedures for PV modulation during LDLT were not done until the postoperative assessment of the graft function and PV flow for possible postoperative modulation of the portal flow accordingly. Postoperative PV flow kept as high as 30 cm/s. By the end of the 1st week, there was a progressive deterioration of the total bilirubin profile (peak as 19.4 mg/dL) and ascitic fluid amount exceeded 1000 mL/day. Therefore, splenic artery embolization was done effectively and safely on the 10th postoperative day (POD) to reverse early allograft dysfunction as PV flow significantly decreased to keep within 20 cm/s and serum total bilirubin levels gradually declined with decreased amounts of ascites below 500 mL on POD 11 and thereafter. The patient was discharged on POD 28 with good condition.

Conclusions

SFSS can be prevented or reversed by the portal inflow modulation, even by post-transplant procedure. This case emphasizes that keeping accessible angiographic treatment options for PV modulation, such as splenic artery embolization, after LDLT is quite feasible.

"Small-for-Flow" Syndrome: Concept Evolution

BACKGROUND

The "Small-for-Size" syndrome is defined as a liver failure after a liver transplant with a reduced graft or after a major hepatectomy. The later coined "Small-for-Flow" syndrome describes the same situation in liver resections but based on hemodynamic intraoperative parameters (portal pressure > 20 mmHg and/or portal flow > 250 ml/min/100 g). This focuses on the damage caused by the portal hyperafflux related to the volume of the remnant.

METHODS

Relevant studies were reviewed using Medline, PubMed, and Springer databases.

RESULTS

Portal hypertension after partial hepatectomies also leads to a higher morbidity and mortality. There are plenty of experimental studies focusing on flow rather than size. Some of them also perform different techniques to modulate the portal inflow. The deleterious effect of high posthepatectomy portal venous pressure is known, and that is why the idea of portal flow modulation during major hepatectomies in humans is increasing in everyday clinical practice.

CONCLUSIONS

Considering the extensive knowledge obtained with the experimental models and good results in clinical studies that analyze the "Small-for-Flow" syndrome, we believe that measuring portal flow and portal pressure during major liver resections should be performed routinely in extended liver resections. Applying these techniques, the knowledge of hepatic hemodynamics would be improved in order to advance against posthepatectomy liver failure.

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.

Is Portal Inflow Modulation Always Necessary for Successful Utilization of Small Volume Living Donor Liver Grafts?

Although the well-accepted lower limit of the graft-to-recipient weight ratio (GRWR) for successful living donor liver transplantation (LDLT) remains 0.80%, many believe grafts with lower GRWR may suffice with portal inflow modulation (PIM), resulting in equally good recipient outcomes. This study was done to evaluate the outcomes of LDLT with small-for-size grafts (GRWR <0.80%). Of 1321 consecutive adult LDLTs from January 2012 to December 2017, 287 (21.7%) had GRWR <0.80%. PIM was performed (hemiportocaval shunt [HPCS], n = 109; splenic artery ligation [SAL], n = 14) in 42.9% patients. No PIM was done if portal pressure (PP) in the dissection phase was <16 mm Hg. Mean age of the cohort was 49.3 ± 9.1 years. Median Model for End-Stage Liver Disease score was 14, and the lowest GRWR was 0.54%. A total of 72 recipients had a GRWR <0.70%, of whom 58 underwent HPCS (1 of whom underwent HPCS + SAL) and 14 underwent no PIM, whereas 215 had GRWR between 0.70% and 0.79%, of whom 51 and 14 underwent HPCS and SAL, respectively. During the same period, 1034 had GRWR ≥0.80% and did not undergo PIM. Small-for-size syndrome developed in 2.8% patients. Three patients needed shunt closure at 1 and 4 weeks and 60 months. The 1-year patient survival rates were comparable. In conclusion, with PIM protocol that optimizes postperfusion PP, low-GRWR grafts can be used for appropriately selected LDLT recipients with acceptable outcomes.

Comprehensive Characterization of a Porcine Model of The "Small-for-Flow" Syndrome

INTRODUCTION

The term "Small-for-Flow" reflects the pathogenetic relevance of hepatic hemodynamics for the "Small-For-Size" syndrome and posthepatectomy liver failure. We aimed to characterize a large-animal model for studying the "Small-for-Flow" syndrome.

METHODS

We performed subtotal (90%) hepatectomies in 10 female MiniPigs using a simplified transection technique with a tourniquet. Blood tests, hepatic and systemic hemodynamics, and hepatic function and histology were assessed before (Bas), 15 min (t-15 min) and 24 h (t-24 h) after the operation. Some pigs underwent computed tomography (CT) scans for hepatic volumetry (n = 4) and intracranial pressure (ICP) monitoring (n = 3). Postoperative care was performed in an intensive care unit environment.

RESULTS

All hepatectomies were successfully performed, and hepatic volumetry confirmed liver remnant volumes of 9.2% [6.2-11.2]. The hepatectomy resulted in characteristic hepatic hemodynamic alterations, including portal hyperperfusion, relative decrease of hepatic arterial blood flow, and increased portal pressure (PP) and portal-systemic pressure gradient. The model reproduced major diagnostic features including the development of cholestasis, coagulopathy, encephalopathy with increased ICP, ascites, and renal failure, hyperdynamic circulation, and hyperlactatemia. Two animals (20%) died before t-24 h. Histological liver damage was observed at t-15 min and at t-24 h. The degree of histological damage at t-24 h correlated with intraoperative PP (r = 0.689, p = 0.028), hepatic arterial blood flow (r = 0.655, p = 0.040), and hepatic arterial pulsatility index (r = 0.724, p = 0.066). All animals with intraoperative PP > 20 mmHg presented liver damage at t-24 h.

CONCLUSION

The present 90% hepatectomy porcine experimental model is a feasible and reproducible model for investigating the "Small-for-Flow" syndrome.

Older Donor Age Is a Risk Factor for Negative Outcomes After Adult Living Donor Liver Transplantation Using Small-for-Size Grafts

Adult-to-adult living donor liver transplantation (ALDLT) using small-for-size grafts (SFSGs), ie, a graft with a graft-to-recipient weight ratio (GRWR) <0.8%, has been a challenge that should be carefully dealt with, and risk factors in this category are unclear. Therefore, we aimed to examine the risk factors and outcomes of ALDLT using SFSGs over a 13-year period in 121 patients who had undergone their first ALDLT using SFSGs. Small-for-size syndrome (SFSS), early graft loss, and 1-year mortality were encountered in 21.6%, 14.9%, and 18.4% of patients, respectively. By multivariate analysis, older donor age (≥45 years) was an independent risk factor for SFSS (odds ratio [OR], 4.46; P = 0.004), early graft loss (OR, 4.11; P = 0.02), and 1-year mortality (OR, 3.76; P = 0.02). Child-Pugh C class recipients were associated with a higher risk of SFSS development (P = 0.013; OR, 7.44). Despite no significant difference between GRWR categories in the multivariate outcome analysis of the whole population, in the survival analysis of the 2 donor age groups, GRWR <0.6% was associated with significantly lower 1-year survival than the other GRWR categories in the younger donor group. Moreover, in the high final portal venous pressure (PVP) group (>15 mm Hg), younger ABO-compatible donors showed 100% 1-year survival with a significant difference from the group of other donors. Older donor age was an independent risk factor for SFSS, early graft loss, and 1-year mortality after ALDLT using SFSGs. GRWR should not be <0.6%, and PVP modulation is indicated when grafts from older or ABO-incompatible donors are used.

Impact of Donor Age on Recipient Survival in Adult-to-Adult Living-donor Liver Transplantation

OBJECTIVE

To investigate the influence of donor age on recipient outcome after living-donor partial liver transplantation (LDLT).

BACKGROUND

Donor age is a well-known prognostic factor in deceased donor liver transplantation; however, its role in LDLT remains unclear.

METHODS

We retrospectively analyzed 315 consecutive cases of primary adult-to-adult LDLT in our center between April 2006 and March 2014. Recipients were divided into 5 groups according to the donor age: D-20s (n = 60); D-30s (n = 72); D-40s (n = 57); D-50s (n = 94); and D-60s (n = 32). The recipient survival and the association with various clinical factors were investigated.

RESULTS

Recipient survival proportions were significantly higher in D-20s compared with all the other groups (P = 0.008, < 0.001, < 0.001, and = 0.006, vs D-30s, -40s, -50s, and -60s, respectively), whereas there was no association between recipient survival and their own age. There are 3 typical relationships between donors and recipients in adult-to-adult LDLT: from child-to-parent, between spouses/siblings, and from parent-to-child. The overall survival in child-to-parent was significantly higher than in spouses/siblings (P = 0.002) and in parent-to-child (P = 0.005), despite significantly higher recipient age in child-to-parent [59 (42-69) years, P < 0.001]. Contrastingly, parent-to-child exhibited the lowest survival, despite the youngest recipient age [26 (20-43) years, P < 0.001]. In addition, younger donor age exhibited significantly better recipient survival both in hepatitis C virus-related and in non-hepatitis C virus diseases. Univariate and multivariate analyses both demonstrated that donor age and graft-type (right-sided livers) are independent prognostic factors for recipient survival.

CONCLUSIONS

Donor age is an independent, strong prognostic factor in adult-to-adult LDLT.

Splenectomy in living donor liver transplantation and risk factors of portal vein thrombosis

BACKGROUND

Graft inflow modulation (GIM) during adult-to-adult living donor liver transplantation (LDLT) is a common strategy to avoid small-for-size syndrome, and some transplant surgeons attempt small size graft strategy with frequent GIM procedures, which are mostly performed by splenectomy, in LDLT. However, splenectomy can cause serious complications such as portal vein thrombosis and overwhelming postsplenectomy infection.

METHODS

Forty-eight adult-to-adult LDLT recipients were enrolled in this study and retrospectively reviewed. We applied the graft selection criteria, which routinely fulfill graft-to-recipient weight ratio ≥ 0.8%, and consider GIM as a backup strategy for high portal venous pressure (PVP).

RESULTS

In our current strategy of LDLT, splenectomy was performed mostly due to hepatitis C and splenic arterial aneurysms, but splenectomy for GIM was intended to only one patient (2.1%). The final PVP values ≤ 20 mmHg were achieved in all recipients, and no significant difference was observed in patient survival or postoperative clinical course based on whether splenectomy was performed or not. However, 6 of 18 patients with splenectomy (33.3%) developed postsplenectomy portal vein thrombosis (PVT), while none of the 30 patients without splenectomy developed PVT after LDLT. Splenectomy was identified as a risk factor of PVT in this study (P < 0.001). Our study revealed that a lower final PVP could be risk factor of postsplenectomy PVT.

CONCLUSIONS

Using sufficient size grafts was one of the direct solutions to control PVP, and allowed GIM to be reserved as a backup procedure. Splenectomy should be avoided as much as possible during LDLT because splenectomy was found to be a definite risk factor of PVT. In splenectomy cases with a lower final PVP, a close follow-up is required for early detection and treatment of PVT.

Impact of Graft Quality and Fluid Overload on Postoperative Massive Ascites After Living Donor Liver Transplantation

After living donor liver transplantation, we encounter cases with massive ascites, which is difficult to manage. We analyzed the risk factors for massive ascites after living donor liver transplantation. The subjects were 100 adult recipients who underwent living donor liver transplantation at Kyoto University Hospital from 2013 to 2017. We retrospectively assessed patient, graft, operative factors, and percent fluid overload, which were defined as [(weight on the day - preoperative weight)/preoperative weight] × 100%. We defined the massive ascites group as having a14-day average ascites ≥ 2500 mL and the mild ascites group as having a 14-day average ascites < 2500 mL. Forty-seven patients were included in the massive group, and 53 patients were included in the mild group. There was no difference in short- and long-term survival. In multivariate analysis, the presence of preoperative ascites (P = .0008), 14-day average percent fluid overload ≥ 14.5% (P = .0095), graft-to-recipient weight ratio < 0.86 (P = .0253), and donors' age ≥ 47 years (P = .0466) were identified as independent risk factors for massive ascites after living donor liver transplantation. A liver graft with a small graft-to-recipient weight ratio or from an elderly donor, which may indicate poor graft quality, presence of preoperative ascites, and postoperative fluid overload were associated with massive ascites after living donor liver transplantation.

Outcomes of adult patients adopting small-for-size grafts in living donor liver transplantation: A systematic review and meta-analysis

BACKGROUND

Small-for-size graft (SFSG) has emerged as one of the very contentions in adult-to-adult living donor liver transplantation (LDLT) as a certain graft size is related to recipients' prognosis. Graft-to-recipient weight ratio (GRWR) ≥0.8% was considered as a threshold to conduct LDLT. However, this also has been challenged over decades as a result of technique refinements. For a better understanding of SFSG in practice, we conducted this meta-analysis to compare the perioperative outcomes and long-term outcomes between patients adopting the grafts with a lower volume (GRWR < 0.8%, SFSG group) and sufficient volume (GRWR ≥ 0.8%, non-SFSG group) in adult-to-adult LDLT.

DATA SOURCES

The studies comparing recipients adopting graft with a GRWR < 0.8% and ≥ 0.8% were searched by three authors independently in PubMed, Web of Science, Embase, the Cochrane Library, MEDLINE and Google Scholar databases until September 2018 and data were analyzed by RevMan 5.3.5.

RESULTS

Sixteen studies with a total of 3272 subjects were included in this meta-analysis. In terms of small-for-size syndrome (SFSS), no significant difference was found in subjects enrolled after year 2010 (before 2010, OR=3.00, 95% CI: 1.69-5.35, P = 0.0002; after 2010, OR=1.23, 95% CI: 0.79-1.90, P = 0.36; P for interaction: 0.02). There was no significant difference in operative duration, blood loss, cold ischemia time, biliary complications, acute rejection, postoperative bleeding, hospitalization time, perioperative mortality, and 1-, 3- and 5-year overall survival rates between two groups.

CONCLUSIONS

This meta-analysis suggested that adopting SFSG in adult LDLT has comparable outcomes to those with non-SFSG counterparts since 2010.

Split liver transplantation: Current developments

In 1988, Rudolf Pichlmayr pioneered split liver transplantation (SLT), enabling the transplantation of one donor liver into two recipients - one pediatric and one adult patient. In the same year, Henri Bismuth and colleagues performed the first full right/full left split procedure with two adult recipients. Both splitting techniques were rapidly adopted within the transplant community. However, a SLT is technically demanding, may cause increased perioperative complications, and may potentially transform an excellent deceased donor organ into two marginal quality grafts. Thus, crucial evaluation of donor organs suitable for splitting and careful screening of potential SLT recipients is warranted. Furthermore, the logistic background of the splitting procedure as well as the organ allocation policy must be adapted to further increase the number and the safety of SLT. Under defined circumstances, in selected patients and at experienced transplant centers, SLT outcomes can be similar to those obtained in full organ LT. Thus, SLT is an important tool to reduce the donor organ shortage and waitlist mortality, especially for pediatric patients and small adults. The present review gives an overview of technical aspects, current developments, and clinical outcomes of SLT.

Henoch-Schönlein Purpura After Living Donor Liver Transplantation: Report of the First Case

Henoch-Schönlein purpura (HSP) is a systemic vasculitis affecting the small vessels that mainly presents in children and young adults. It is characterized by tissue deposition of immunoglobulin A (IgA) immune complexes with the classic manifestations of purpura, arthritis, arthralgia, and gastrointestinal and renal involvements. We report a case of HSP nephritis that occurred 2 years after living-donor liver transplantation (LDLT). After pulse steroid administration, the patient's symptoms disappeared and blood markers normalized. To the best of our knowledge, this is the first HSP case to be reported in a liver transplant recipient.

Readdressing the Middle Hepatic Vein in Right Lobe Liver Donation: Triangle of Safety

For equipoising donor safety and optimal recipient outcomes, we adopted an algorithmic "triangle of safety" approach to retrieve 3 types of right lobe liver grafts (RLGs), namely, the modified extended right lobe graft (MERLG), the partial right lobe graft (PRLG), and the modified right lobe graft (MRLG). Reconstruction to achieve a single wide anterior sector outflow was ensured in all patients. We present donor and recipient outcomes based on our approach in 665 right lobe (RL) living donor liver transplantations (LDLTs) performed from January 2013 to August 2015. There were 347 patients who received a MERLG, 117 who received a PRLG, and 201 who received a MRLG. A right lobe graft (RLG) with a middle hepatic vein was retrieved only in 3 out of 18 donors with steatosis >10%. Cold ischemia time was significantly more and remnant volume was less in the MRLG group. Of the donors, 29.3% had complications (26% Clavien-Dindo grade I, II) with no statistically significant difference among the groups. The Model for End-Stage Liver Disease score was higher in the MERLG group. There were 34 out of 39 with a graft-to-recipient weight ratio (GRWR) of <0.7% who received a MERLG with inflow modulation. Out of 4 patients who developed small-for-size syndrome in this group, 2 died. The 90-day patient survival rate was similar among different GRWRs and types of RLG. In conclusion, a selective and tailored approach for RL donor hepatectomy based on optimal functional volume and metabolic demands not only addresses the key issue of double equipoise in LDLT but also creates a safe path for extending the limits.

Impact of preserved collateral veins on small-for-size grafts in living donor liver transplantation

AIM

Graft size is a critical issue in living donor liver transplantation (LDLT). We hypothesized that too much portal flow could possibly be diverted into pre-existing collateral veins, alleviating small-for-size syndrome (SFSS) in LDLT. This study evaluated the impact of the preserved collateral veins in the outcomes of LDLT using a small-for-size graft.

METHODS

For patient safety, a graft-to-recipient weight ratio (GRWR) <0.8% was strictly confined to patients with collateral veins (group A), and the patient group was compared in a 1:3 ratio to a matched group of patients with GRWR ≥0.8% (group B) using propensity score analysis.

RESULTS

Forty and 120 patients were included in group A and B, respectively. No significant differences in baseline patient characteristics were observed between the two groups except for graft weight and GRWR. The lowest GRWR was 0.4%. The graft portal inflow showed no significant differences for 7 days after graft implantation, ranging from 1668 to 5100 mL/min. Small-for-size syndrome occurred in no patients (0.0%) in group A and in 10 (8.3%) in group B (P = 0.067). Overall survival rates at 1, 3, and 5 years were not different between the two groups (85.0%, 82.5%, and 82.5% vs. 92.5%, 86.7%, and 85.0%, respectively; P = 0.670).

CONCLUSION

Pre-existing collateral veins saved during surgery may have a reserve buffer for excessive portal flow to obviate SFSS in LDLT.

Patterns of Early Allograft Dysfunction in Adult Live Donor Liver Transplantation: The A2ALL Experience

BACKGROUND

Early allograft dysfunction (EAD) after living donor liver transplantation (LDLT) has often been attributed to inadequate graft size, and termed small-for-size syndrome. Early allograft dysfunction definitions include a variable constellation of findings, including hyperbilirubinemia, coagulopathy, encephalopathy, and ascites formation. Among putative causes of EAD after LDLT are excessive portal pressure and/or flow. Our objective was to evaluate patterns of EAD after LDLT.

METHODS

In this study, 631 LDLT recipients were monitored for complications, EAD (defined by postoperative day 7 bilirubin >10 mg/dL or international normalized ratio >1.6), and graft failure. Approximately 200 had portal venous and arterial pressure and flow measurements before and after LDLT. Portal inflow modification (splenic artery ligation, hemiportocaval shunt, or splenectomy) was performed at the discretion of the operating surgeon. Associations between EAD and recipient, donor, and transplant factors were examined using multivariable logistic regression.

RESULTS

Risk of EAD was associated with left lobe grafts, lower graft weight among left lobes, higher preoperative bilirubin, higher portal reperfusion pressure, higher donor age, and higher donor body mass index. The risk of graft loss within the first 90 days was 5.2 times higher for recipients with EAD versus those without EAD (P < 0.001).

CONCLUSIONS

Early allograft dysfunction can be defined using postoperative day 7 laboratory values that are highly predictive of early graft failure within 90 days. Risk factors associated with EAD after LDLT include: graft type and size, preoperative bilirubin, portal reperfusion pressure, donor age, and donor body mass index.

A Novel Predictor of Posttransplant Portal Hypertension in Adult-To-Adult Living Donor Liver Transplantation: Increased Estimated Spleen/Graft Volume Ratio

BACKGROUND

In adult living donor liver transplantation (ALDLT), graft-to-recipient weight ratio of less than 0.8 is incomplete for predicting portal hypertension (>20 mm Hg) after reperfusion. We aimed to identify preoperative factors contributing to portal venous pressure (PVP) after reperfusion and to predict portal hypertension, focusing on spleen volume-to-graft volume ratio (SVGVR).

METHODS

In 73 recipients with ALDLT between 2002 and 2013, first we analyzed survival according to PVP of 20 mm Hg as the threshold, evaluating the efficacy of splenectomy. Second, we evaluated various preoperative factors contributing to portal hypertension after reperfusion.

RESULTS

All of the recipients with PVP greater than 20 mm Hg (n = 19) underwent PVP modulation by splenectomy, and their overall survival was favorable compared with 54 recipients who did not need splenectomy (PVP ≤ 20 mm Hg). Graft-to-recipient weight ratio had no correlation with PVP.Multivariate analysis revealed that estimated graft and spleen volume were significant factors contributing to PVP after reperfusion (P < 0.0001 and P < 0.0001, respectively). Furthermore, estimated SVGVR showed a significant negative correlation to PVP after reperfusion (R = 0.652), and the best cutoff value for portal hypertension was 0.95.

CONCLUSIONS

In ALDLT, preoperative assessment of SVGVR is a good predictor of portal hypertension after reperfusion can be used to indicate the need for splenectomy before reperfusion.

Preconditioning by portal vein embolization modulates hepatic hemodynamics and improves liver function in pigs with extended hepatectomy

BACKGROUND

Portal vein embolization is performed weeks before extended hepatic resections to increase the future liver remnant and prevent posthepatectomy liver failure. Portal vein embolization performed closer to the operation also could be protective, but worsening of portal hyper-perfusion is a major concern. We determined the hepatic hemodynamic effects of a portal vein embolization performed 24 hours prior to hepatic operation.

METHODS

An extended (90%) hepatectomy was performed in swine undergoing (portal vein embolization) or not undergoing (control) a portal vein embolization 24 hours earlier (n = 10/group). Blood tests, hepatic and systemic hemodynamics, hepatic function (plasma disappearance rate of indocyanine green), liver histology, and volumetry (computed tomographic scanning) were assessed before and after the hepatectomy. Hepatocyte proliferating cell nuclear antigen expression and hepatic gene expression also were evaluated.

RESULTS

Swine in the control and portal vein embolization groups maintained stable systemic hemodynamics and developed similar increases of portal blood flow (302 ± 72% vs 486 ± 92%, P = .13). Portal pressure drastically increased in Controls (from 9.4 ± 1.3 mm Hg to 20.9 ± 1.4 mm Hg, P < .001), while being markedly attenuated in the portal vein embolization group (from 11.4 ± 1.5 mm Hg to 16.1 ± 1.3 mm Hg, P = .061). The procedure also improved the preservation of the hepatic artery blood flow, liver function, and periportal edema. These effects occurred in the absence of hepatocyte proliferation or hepatic growth and were associated with the induction of the vasoprotective gene Klf2.

CONCLUSION

Portal vein embolization preconditioning represents a potential hepato-protective strategy for extended hepatic resections. Further preclinical studies should assess its medium-term effects, including survival. Our study also supports the relevance of hepatic hemodynamics as the main pathogenetic factor of post-hepatectomy liver failure.

Living donor liver transplantation in patients weighing ≥100 kg: Low graft weight and obesity do not impact outcomes

Living donor liver transplantation (LDLT) in obese patients raises concerns with regards to obtaining grafts of "adequate" graft-to-recipient weight ratio (GRWR) and the impact of obesity on the outcomes of LDLT. LDLT outcomes in patients weighing ≥100 kg were compared with those weighing <100 kg. Patients weighing ≥100 kg were divided into 3 categories based on the GRWR of the grafts they received. Groups 1, 2, and 3 included patients with GRWR ≥0.8%, between 0.65% and 0.8%, and <0.65%, respectively. The 56 (6.5%) adult liver transplants were performed in patients weighing 100 kg or more. Except for higher mean body mass index (35.8 versus 25.2 kg/m² ; P value < 0.01) and grafts of lower GRWR in obese patients (0.74% versus 1.02%; P value < 0.01), all other parameters were similar between the 2 groups. Despite obesity and smaller grafts, the posttransplant outcomes such as day to normal bilirubin and international normalized ratio; infective, respiratory, and biliary complications; and hospital mortality were similar between the 2 groups. On comparing obese patients in the 3 GRWR categories, except for graft weight (985 versus 769 versus 646 g; P value < 0.01), all the pretransplant parameters were comparable. There was no significant difference in terms of graft function, postoperative morbidity, and hospital mortality between patients with grafts of normal GRWR and those with grafts of low and very low GRWR. Grafts of low GRWR give satisfactory results in obese patients undergoing LDLT and obesity does not adversely impact the outcome of LDLT. Liver Transplantation 23:35-42 2017 AASLD.

Graft-to-recipient weight ratio threshold adjusted to the model for end-stage liver disease score for living donor liver transplantation

The graft-to-recipient weight ratio (GRWR) is an important selection criterion for living donor liver transplantation (LDLT). The generally accepted threshold is known to be 0.8%. We believe that this threshold can be reduced under certain conditions. The aim of this study was to evaluate the results of these patients with GRWR < 0.8%. Between 2004 and 2015, 649 patients underwent right lobe LDLT for end-stage liver disease in adult patients. All recipients who had GRWR < 0.8% were identified. The data of these patients were retrospectively analyzed and compared to patients with GRWR ≥ 0.8%. There were 43 patients with GRWR < 0.8%. Out of these patients, 7 (16%) had GRWR of 0.6%. The median Model for End-Stage Liver Disease (MELD) score was 15, and the median donor age was 30 years. Anterior segment drainage was ensured. Portal inflow modulation was performed by splenic artery ligation according to the portal flow. Postoperative complications were seen in 6 (14%) patients. Of all 43 patients, 3 (7%) died perioperatively within 1 month, and 1 (2%) patient underwent retransplantation due to graft failure. The mean hospital stay was 18 days. The 1-year survival rate was 93%. None of the patients had a laboratory MELD score above 20. The comparison of the results with the patients who had GRWR ≥ 0.8% has shown no significant difference, except MELD score, body mass index (BMI), and rate of anterior segment drainage. The GRWR can be decreased even to 0.6% if the MELD score is below 20, donor age is below 45 years, and there are no signs for any hepatosteatosis of the donor graft. In these patients, it is essential that the anterior segment drainage is secured and the portal inflow modulation is performed according to the portal flow. Liver Transplantation 22 1643-1648 2016 AASLD.

Modified Hepatic Venous Plane: A Key Factor for Improving Preoperative MDCT Donor Volume Prediction in Living-Donor Liver Transplantation

OBJECTIVE

The aim of this work was to present our experience using a modified hepatic venous plane in multidetector computerized tomography (MDCT) for reducing the discrepancy between preoperative liver volume estimation and intraoperative weight (IOW) measurement in living-donor liver transplantation (LDLT).

METHODS

We retrospectively reviewed the medical records of 57 consecutive living donors with the use of MDCT as a modality for volumetric assessment for LDLT from May 2007 to January 2015. We divided living donors into 2 groups according to surgical methods: right hepatectomy (RH) and left hepatectomy (LH). Initial liver volumetric measurement (group I) was assessed. After discussions with radiologist, the transplantation surgeon used a modified hepatic venous plane for surgical significant middle hepatic venous variants (>5 mm) in 16 living donors and applied the initial surgical plane in the remaining for the modified donor liver volumetric measurement (group II). We then compared the correlations of these 2 groups with the use of IOW.

RESULTS

The overall correlation (r) between group I and IOW was 0.947. The correlations (r) between group I and IOW were 0.872 and 0.955 for RH and LH, respectively. Compared with group I, group II showed better correlation with IOW: r = 0.949 and 0.981 for RH and LH, respectively. The overall correlation (r) between group II and IOW was 0.980, and the error ratio was 5.95 ± 5.05%.

CONCLUSIONS

Our study showed that using a modified hepatic venous plane in preoperative MDCT, after good communication between transplant surgeon and radiologist, can provide more accurate liver volume estimation and achieve a better correlation with IOW in LDLT.

Impact of splenic artery ligation after major hepatectomy on liver function, regeneration and viability

It was reported that prevention of acute portal overpressure in small-for-size livers by inflow modulation results in a better postoperative outcome. The aim is to investigate the impact of portal blood flow reduction by splenic artery ligation after major hepatectomy in a murine model. Forty-eight rats were subjected to an 85% hepatectomy or 85% hepatectomy and splenic artery ligation. Both groups were evaluated at 24, 48, 72 and 120 post-operative hours: liver function, regeneration and viability. All methods and experiments were carried out in accordance with Coimbra University guidelines. Splenic artery ligation produces viability increase after 24 h, induces a relative decrease in oxidative stress during the first 48 hours, allows antioxidant capacity increment after 24 h, which is reflected in a decrease of half-time normalized liver curve at 48 h and at 72 h and in an increase of mitotic index between 48 h and 72 h. Splenic artery ligation combined with 85% hepatectomy in a murine model, allows portal inflow modulation, promoting an increase in hepatocellular viability and regeneration, without impairing the function, probably by inducing a less marked elevation of oxidative stress at first 48 hours.

The beneficial role of simultaneous splenectomy after extended hepatectomy: experimental study in pigs

BACKGROUND

The role of hepatic hemodynamic modulation in the development of "small-for-size" syndrome (SFSS) after extended hepatectomy (EH) or living-donor liver transplantation is still controversial. We have designed an experimental study to investigate the effect of hemodynamic parameters of the liver circulation on the development of SFSS after EH in a porcine model.

METHODS

Eighteen pigs were randomly divided into two groups: group A has received EH (75%-80%) without splenectomy, and group B with EH and simultaneous splenectomy was carried out. Portal hemodynamics, liver function tests, histologic findings, injury and survival rates were compared between groups A and B.

RESULTS

The 7-d survival rate in the splenectomy group was significantly improved compared with group A (88.9% versus 44.4%, P < 0.05). Portal vein pressure, portal vein flow, and liver function tests in the splenectomy group were significantly lower than in group A immediately after splenectomy and postoperatively until the day of sacrifice. Histologic findings in group A clearly illustrate severe inflammation, bridging necrosis, ischemic cholangitis, and severe congestion, while in group B there were less serious histologic changes.

CONCLUSIONS

Our experimental study indicates that perioperative portal modulation can successfully prevent the manifestation of SFSS after EH. Therefore, by focusing on "flow" rather than on "size," researchers may understand better the pathophysiology of this syndrome.

Systemic hemodynamics in advanced cirrhosis: Concerns during perioperative period of liver transplantation

Advanced liver cirrhosis is usually accompanied by portal hypertension. Long-term portal hypertension results in various vascular alterations. The systemic hemodynamic state in patients with cirrhosis is termed a hyperdynamic state. This peculiar hemodynamic state is characterized by an expanded blood volume, high cardiac output, and low total peripheral resistance. Vascular alterations do not disappear even long after liver transplantation (LT), and recipients with cirrhosis exhibit a persistent systemic hyperdynamic state even after LT. Stability of optimal systemic hemodynamics is indispensable for adequate portal venous flow (PVF) and successful LT, and reliable parameters for optimal systemic hemodynamics and adequate PVF are required. Even a subtle disorder in systemic hemodynamics is precisely indicated by the balance between cardiac output and blood volume. The indocyanine green (ICG) kinetics reflect the patient’s functional hepatocytes and effective PVF, and PVF is a major determinant of the ICG elimination constant (kICG) in the well-preserved allograft. The kICG value is useful to set the optimal PVF during living-donor LT and to evaluate adequate PVF after LT. Perioperative management has a large influence on the postoperative course and outcome; therefore, key points and unexpected pitfalls for intensive management are herein summarized. Transplant physicians should fully understand the peculiar systemic hemodynamic behavior in LT recipients with cirrhosis and recognize the critical importance of PVF after LT.

Oral administration of polyamines ameliorates liver ischemia/reperfusion injury and promotes liver regeneration in rats

Polyamines are essential for cell growth and differentiation. They play important roles in protection from liver damage and promotion of liver regeneration. However, little is known about the effect of oral exogenous polyamine administration on liver damage and regeneration. This study investigated the impact of polyamines (spermidine and spermine) on ischemia/reperfusion injury (IRI) and liver regeneration. We used a rat model in which a 70% hepatectomy after 40 minutes of ischemia was performed to mimic the clinical condition of living donor partial liver transplantation (LT). Male Lewis rats were separated into 2 groups: a polyamine group given polyamines before and after operation as treatment and a vehicle group given distilled water as placebo. The levels of serum aspartate aminotransferase and alanine aminotransferase at 6, 24, and 48 hours after reperfusion were significantly lower in the polyamine group compared with those in the vehicle group. Polyamine treatment reduced the expression of several proinflammatory cytokines and chemokines at 6 hours after reperfusion. Histological analysis showed significantly less necrosis and apoptosis in the polyamine group at 6 hours after reperfusion. Sinusoidal endothelial cells were also well preserved in the polyamine group. In addition, the regeneration of the remnant liver at 24, 48, and 168 hours after reperfusion was significantly accelerated, and the Ki-67 labeling index and the expressions of proliferating cell nuclear antigen and phosphorylated retinoblastoma protein at 24 hours after reperfusion were significantly higher in the polyamine group compared with those in the vehicle group. In conclusion, perioperative oral polyamine administration attenuates liver IRI and promotes liver regeneration. It might be a new therapeutic option to improve the outcomes of partial LT. Liver Transplantation 22 1231-1244 2016 AASLD.

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.

Hepatic Hemodynamic Changes Following Stepwise Liver Resection

AIM

Extended liver resection has increased during the last decades. However, hepatic hemodynamic changes after resection and the consequent complications like post hepatectomy liver failure are still a challenging issue. The aim of this study was to systematically evaluate the role of stepwise liver resection on hepatic hemodynamic changes.

METHODS

To evaluate this effect we performed 25, 50, and 75 % sequential liver resections in 10 pigs. Before and after each resection, the hepatic artery flow and portal vein flow in relation to the remnant liver volume (RLV) as well as hepatic vascular pressures were measured and compared between the groups.

RESULTS

Following sequential liver resection, the hepatic artery flow /100 g decreases and the portal vein flow increases up to 17 and 167 % following extended liver resection (75 %), respectively. Also, during stepwise liver resection, the portal vein pressure increases gradually up to 33 % following extended hepatectomy (75 %).

CONCLUSION

Sequential decrease in the RLV decreases the hepatic artery flow /100 g and increases the portal vein flow /100 g and portal vein pressure. As the consequence, the liver goes under more poor-oxygenated blood supply and higher pressure. This may be one of the most important mechanisms of the post hepatectomy liver failure in case of extended liver resection.

How far can we lower graft-to-recipient weight ratio for living donor liver transplantation under modulation of portal venous pressure?

BACKGROUND

Smaller size grafts for living donor liver transplantation (LDLT) can enhance donor safety and expand donor availability. We previously reported that modulation of portal venous pressure (PVP) was key for successful LDLT with small grafts, and that it actively lowered graft-to-recipient weight ratio (GRWR) for adult-to-adult LDLT. This retrospective study investigated the outcome of LDLT using small grafts with PVP modulation.

METHOD

This study analyzed 221 adult LDLT patients between March 2008 and December 2013 and divided them into 3 groups based on GRWR: large (L), GRWR ≥ 0.8% (n = 154), medium (M), ≥ 0.7% GRWR < 0.8% (n = 38); and small (S) GRWR < 0.7% (n = 29). Donor and recipient factors, PVP, pressure gradient between PVP and central venous pressure (CVP), occurrence of small for size syndrome (SFSS), ascites, and posttransplant laboratory data were compared across the 3 groups. Patient and graft survival were compared using Kaplan-Meier methods.

RESULTS

There was no difference in patient or graft survival between the 3 groups. Amount of posttransplant ascites and posttransplant International Normalized Ratio were similar, but the S and M groups had more prolonged cholestasis. SFSS was identified in 17%, 13%, and 13% in the S, M, and L groups, respectively (P = NS). Patients with a final PVP of ≤15 mmHg had better survival than patients with a final PVP of >15 mmHg (P < .001). Multivariate analysis showed that donor age >40 years old, final PVP of >15 mmHg, and pressure gradient of PVP-CVP >5 mmHg were risk factors for inferior patient survival.

CONCLUSION

We achieved satisfactory outcomes in LDLT with GRWR as low as 0.6% using PVP modulation. Thus, we currently set a lower limit of GRWR at 0.6% while protecting donor safety and expanding donor availability.

Right posterior segment graft in living donor liver transplantation

AIM

Living donor liver transplantation (LDLT) is widely performed for end-stage liver disease. Liver volume is important for donor safety and recipient survival. In adult-to-adult LDLT, left lobe graft is frequently insufficient for the recipient, while right lobe graft carries a higher donor risk. The right posterior segment graft (RPSG) was introduced to increase donor selection options. However, only a few institutions have reported LDLT with an RPSG.

METHODS

In total, 587 adult recipients underwent LDLT at Kyoto University Hospital from 2001 to 2011. Here, we retrospectively report 14 LDLT with RPSG. All donors underwent volumetric analyses and detailed investigation of the hepatic vein (HV), portal vein (PV), hepatic artery (HA) and biliary duct (BD). Anatomical anomalies were detected in four donors' BD. The mean Model for End-Stage Liver Disease score was 22.6 ± 12.4 points. ABO blood groups were characterized as incompatible in three cases. The mean graft-to-recipient weight ratio was 0.897 ± 0.203.

RESULTS

Donors' postoperative courses were uneventful. To adjust diameters and lengths between grafts and recipients, dual anastomoses for PV reconstruction and graft interpositions for PV and HA reconstruction were required in one case each. HA thrombosis occurred in two cases and PV thrombosis in one. Biliary complications occurred in two cases. Though there was no significant difference in survival following RPSG versus other grafts, critical complications were observed in recipients.

CONCLUSION

The RPSG is a useful option in LDLT. However, careful consideration is required for RPSG harvest and LDLT performance, both before and during surgery.