How transplant surgeons can overcome the inevitable insufficiency of allograft size during adult living-donor liver transplantation: strategy for donor safety with a smaller-size graft and excellent recipient results

Preservation of the round ligament to accommodate transient portal hypertension after major hepatectomy

Purpose

Posthepatectomy liver failure (PHLF) remains a leading cause of death after extensive liver resection. Apart from the size and function of the remaining liver remnant, the development of postresection portal hypertension (pHT) plays a crucial role in the development of PHLF. We hypothesize that the umbilical vein in the preserved round ligament (RL) may recanalize in response to new-onset pHT after extended hepatectomy, thus providing a natural portosystemic shunt.

Methods

In this exploratory study, RL was preserved in 10 consecutive patients undergoing major liver resection. Postoperative imaging was pursued to obtain evidence of reopened umbilical vein in the RL. The postoperative course, including the occurrence of PHLF, as well as the rate of procedure-specific complications were recorded.

Results

None of the 10 cases presented with an adverse event due to preservation of the RL. In 6 cases, postoperative imaging demonstrated reopening of the umbilical vein with hepatofugal flow in the RL. The rates of procedure-related surgical complications were lower than would be expected in this population; in particular, the rate of occurrence of PHLF as defined by the International Study Group of Liver Surgery (ISGLS) was low.

Conclusion

Our results support the theoretical concept of portosystemic pressure relief via a preserved umbilical vein after major liver surgery. As preservation of the RL is easily done, we suggest keeping it intact in extended hepatectomy cases and in patients with preexistent pHT.

A systematic review of the impact of portal vein pressure changes on clinical outcomes following hepatic resection

BACKGROUND

There are evolving data correlating elevated post-hepatic resection portal vein pressure (PVP) with risk of developing post-resection liver failure (PLF) and other complications. As a consequence, modulation of PVP presents a potential strategy to improve outcomes following liver resection (LR). The primary aim of this study was to review the existing evidence regarding the impact of post-resection PVP on clinical outcomes in patients undergoing a LR.

METHODS

Systematic literature searches of electronic databases in accordance with PRISMA were conducted. Changes in PVP and clinical outcomes following liver resection were defined according to the existing literature.

RESULTS

Ten studies, consisting of 712 patients with a median age 61 (52-68) years, were identified that met the inclusion criteria. Of those, 77% (n = 550) underwent a major LR and 27% (n = 195) of patients had cirrhosis. Following LR, the median (range) PVP increased from 11.4 mmHg (median baseline, range 7.3-16.4) to 15.9 mmHg (7.9-19). The overall median incidence of PLF was 19%. Six of the ten studies found an elevated PVP after LR predicted PLF. One study found elevated PVP after LR predicted mortality after LR.

CONCLUSION

Elevated PVP following hepatic resection was associated with increased rates of PLF. It was not possible to define a specific threshold PVP for predicting PLF. Modulation of PVP therefore presents a potential strategy to mitigate the incidence of LR. Future studies should standardize on reporting liver remnant and haemodynamics to better characterize clinical outcomes following LR.

Living donor liver transplantation in small-for-size setting

Small-for-Size Syndrome (SFSS) is one of the most feared complication of adult split liver and living donor liver transplantation. SFSS stems from a disproportionate/excessive portal vein flow relative to the volume of the implanted liver graft, and is currently one of the major practical limits to partial liver grafts' transplantation. In the last few decades many graft inflow modulation (GIM) techniques have been proposed to curtail the portal vein flow, allowing for successful transplantation of small partial liver grafts. Graft inflow modulation techniques span from Splenic Artery Ligation (SAL), to Splenectomy, Porto-Systemic Shunts and the lately proposed Splenic Devascularization. A patient tailored approach balancing the risk of SFSS with GIM specific morbidity, is more important than identifying the ideal GIM technique. Here we summarize the most recently published data to provide general indications in the challenging preoperative choice of a GIM techniques.

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.

Splenic devascularization can replace splenectomy during adult living donor liver transplantation - a historical cohort study

Simultaneous splenectomy (SSPX) in adult living donor liver transplantation (ALDLT) has definitely beneficial roles such as portal flow modulation in small-for-size graft and correction of hypersplenism-related pancytopenia, and so on, but disastrous complications after SSPX often occur. For the first time, we devised unique and innovative splenic devascularization (SDV) procedure to alleviated untoward effects of SSPX but to maintain its benefits for the indicated patients. From April 2013 to December 2014, 520 recipients underwent ALDLT, and the SSPX and SDV were simultaneously performed in 62 (11.9%) and 61 (11.7%) patients, respectively. The most common indication was hypersplenism-related pancytopenia (n = 101), small-for-size graft (n = 14), hepatitis C virus (HCV) (n = 7), and splenic artery aneurysm (n = 1). Postoperative small-for-size graft syndrome (SFSS) was absent in both SSPX and SDV, and preoperative pancytopenia was improved in both groups since postoperative 1 week, although SSPX was more substantial than SDV. Preoperative splenic volume (706.2 ± 282.9 ml) after SDV significantly decreased to 425.5 ± 204.4 ml on 1 month, respectively. In contrast to SDV, SSPX resulted in longer operation time and higher incidence of postoperative complications including mortality. In conclusion, SDV can replace SSPX during ALDLT without hampering its beneficial roles seriously, but get rid of splenectomy-related lethal complication.

Intraoperative Surgical Portosystemic Shunt in Liver Transplantation: Systematic Review and Meta-Analysis

Background

Expanded clinical and surgical techniques in liver transplantation can markedly improve patient and graft survival. The main purpose of this study was to evaluate the efficacy of intraoperative portocaval shunts in liver transplantation.

Material/Methods

Searches were conducted in Cochrane, MEDLINE, and EMBASE databases, and updated in January 2018. The following specific outcomes of interest were defined and evaluated separated using 2 different reviews and meta-analyses for 1) hemi-portocaval shunt (HPCS) and 2) temporary portocaval shunt (TPCS). Comparative studies were analyzed separately for both surgical portocaval shunt modalities.

Results

Only 1 well-designed randomized controlled trial was found. Most studies were retrospective or prospective. Initially, we found 1479 articles. Of those selected, 853 were from PubMed/MEDLINE, 32 were from Cochrane and 594 were from EMBASE. Our meta-analysis included a total of 3232 patients for all the included studies. Results found that 41 patients with HPCS experienced increased 1-year patient survival (OR 16.33; P=0.02) and increased 1-year graft survival (OR 17.67; P=0.01). The TPCS analysis with 1633 patients found patients had significantly shorter intensive care unit length of stay (days) (P=0.006) and hospital length of stay (P=0.02) and had decreased primary nonfunction (PNF) (OR 0.30, P=0.02) and mortality rates (OR 0.52, P=0.01).

Conclusions

Intraoperative surgical portosystemic shunt in relation to liver transplantation with TPCS was able to prevent PNF, decrease hospital length of stay and unit care length of stay. Furthermore, in analyzing data for patients with HPCS, we observed increases in the 1-year graft and patient survival rates. More prospective randomized trials are needed to arrive at a more precise conclusion.

Intentional Modulation of Portal Venous Pressure by Splenectomy Saves the Patient with Liver Failure and Portal Hypertension After Major Hepatectomy: Is Delayed Splenectomy an Acceptable Therapeutic Option for Secondary Portal Hypertension?

BACKGROUND Major or aggressively-extended hepatectomy (MAEH) may cause secondary portal hypertension (PH), and postoperative liver failure (POLF) and is often fatal. Challenges to prevent secondary PH and subsequent POLF, such as shunt creation and splenic arterial ligation, have been reported. However, these procedures have been performed simultaneously only during the initial MAEH. CASE REPORT A 58-year-old female with chronic hepatitis C developed a solitary hepatic cellular carcinoma with portal tumor thrombosis. Blood examination and imaging revealed a decreased platelet count and splenomegaly. Her liver viability was preserved, and collaterals did not develop, and her tumor thrombosis forced us to perform a right hepatectomy from an oncological standpoint. The estimated volume of her liver remnant was 51.8%. A large volume of ascites and pleural effusion were observed on post-operative day (POD) 3, and ascetic infection occurred on POD 14. Hepatic encephalopathy was observed on POD 16. According to the post-operative development of collaterals due to secondary PH, submucosal bleeding in the stomach occurred on POD 37. Though it is unclear whether delayed portal venous pressure (PVP) modulation after MAEH is effective, a therapeutic strategy for recovery from POLF may involve PVP modulation to resolve intractable PH. We performed a splenectomy on POD 41 to reduce PVP. The initial PVP value was 32 mm Hg, and splenectomy decreased PVP to 23 mm Hg. Thereafter, she had a complete recovery from POLF. CONCLUSIONS Our thought-provoking case is the first successfully-treated case of secondary PH and POLF after MAEH, achieved by delayed splenectomy for PVP modulation.

Renoportal Anastomosis in Left Lateral Lobe Living Donor Liver Transplantation: A Pediatric Case

In adult liver transplantation, renoportal anastomosis (RPA) has been introduced as a useful technique for patients with grade 4 portal vein thrombosis and a splenorenal shunt. Here, we report a pediatric case in which RPA allowed a left lateral lobe living donor liver transplantation (LDLT) despite portal vein thrombosis and a large splenorenal shunt. At 36 days old, the patient underwent a Kasai operation for biliary atresia. At 17 months old, she underwent LDLT because of repetitive cholangitis. Pretransplant examinations revealed a large splenorenal shunt and portal vein thrombosis. Simple end-to-end portal reconstruction and clamping of the collateral route after removing the thrombosis were unsuccessful. Thus, RPA was performed using a donor superficial femoral vein as an interpositional graft. The portal vein pressure was 20 mm Hg after arterial reperfusion. Ligation of the splenic artery reduced the portal vein pressure. Although she developed severe acute cellular rejection and chylous ascites, there were no signs of portal vein complications. She was discharged 73 days after transplantation without any signs of renal dysfunction. The patient's condition was good at her last follow-up, 22 months after transplantation. To our knowledge, this is the youngest case of RPA in pediatric left lateral lobe LDLT. Additionally, this is the first case of RPA with splenic artery ligation and using the donor's superficial femoral vein as the venous graft for RPA. Although long-term follow-up is necessary, RPA could be a salvage option in LDLT in infants if other methods are unsuccessful.

Portosystemic collaterals in living donor liver transplantation: What is all the fuss about?

Portosystemic collaterals are a common finding in patients with cirrhosis undergoing liver transplantation. Recently, there has been a renewed interest regarding their significance in the setting of living donor liver transplantation (LDLT) due to concerns of graft hypoperfusion or hyperperfusion and its impact on early posttransplant outcomes. Presence of these collaterals has greater significance in the LDLT setting when compared with the deceased donor liver transplantation setting as dictated by the difference in the physiology of partial liver grafts. We discuss current thinking of portal flow dynamics and the techniques for dealing with this clinical problem. Liver Transplantation 23 537-544 2017 AASLD.

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 inflow modulation in adult-to-adult living donor liver transplantation: A systematic review

INTRODUCTION

Small-for-size syndrome (SFSS) has an incidence between 0 and 43% in small-for-size graft (SFSG) adult living donor liver transplantation (LDLT). Portal hypertension following reperfusion and the hyperdynamic splanchnic state are reported as the major triggering factors of SFSS. Intra- and postoperative strategies to prevent or to reduce its onset are still under debate. We analyzed graft inflow modulation (GIM) during adult LDLT considering the indications, efficacy of the available techniques, changes in hemodynamics and outcomes.

MATERIALS AND METHODS

A systematic literature search was performed using PubMed, EMBASE, Scopus and the Cochrane Library Central. Treatment outcomes including in-hospital mortality and morbidity, re-transplantation rate, 1-, 3-, and 5-year patient overall survival and 1-, 3-, and 5-year graft survival rates, hepatic artery and portal vein flows and pressures before and after inflow modulation were analyzed.

RESULTS

From 563 articles, 12 studies dated between 2003 and 2014 fulfilled the selection criteria and were therefore included in the study. These comprised a total of 449 adult patients who underwent inflow modulation during adult-to-adult LDLT. Types of GIM described were splenic artery ligation, splenectomy, meso-caval shunt, spleno-renal shunt, portocaval shunt, and splenic artery embolization. Mortality and morbidity ranged between 0 and 33% and 17% and 70%, respectively. Re-transplantation rates ranged between 0% and 25%. GIM was associated with good survival for both graft and recipients, reaching an 84% actuarial rate at 5 years. Through the use of GIM, irrespective of the technique, a statistically significant reduction of PVF and PVP was obtained.

CONCLUSIONS

GIM is a safe and efficient technique to avoid or limit portal hyperperfusion, especially in cases of SFSG, decreasing overall morbidity and improving outcomes.

Splenectomy is not indicated in living donor liver transplantation

Simultaneous splenectomy (SPX) is preferentially performed in living donor liver transplantation (LDLT) to modulate portal flow; increase postoperative platelet count, especially among those with hepatitis C virus (HCV) infection; and modulate the immunologic status in ABO-incompatible cases. The negative effects of the procedure, however, are not well established. Records of 395 LDLTs performed at our institution, including 169 (42.8%) patients with simultaneous SPX and 226 (57.2%) patients with spleen preservation, were reviewed with special reference to the simultaneous SPX cases. The most common indication for SPX was HCV-related disease (n = 114), followed by low preoperative platelet count (n = 52), and other reasons (n = 3). Simultaneous splenectomy did not increase the platelet count in the early postoperative period, but the incidence of reoperation for postoperative hemorrhage was increased, mainly at the SPX site, within the first week. In addition, the operative time, intraoperative blood loss, and incidence of lethal infectious disease were significantly higher in the SPX group, whereas the incidence of small-for-size syndrome was comparable between groups. Finally, SPX was an independent predictor for both postoperative hemorrhage (odds ratio [OR] = 2.451; 95% confidence interval [CI] = 1.285-4.815; P = 0.006) and lethal infectious complication (OR = 3.748; 95% CI = 1.148-14.001; P = 0.03). In conclusion, on the basis of the present findings, we do not recommend simultaneous SPX in LDLT. Liver Transplantation 22 1526-1535 2016 AASLD.

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.

Fibrosing cholestatic hepatitis C in post-transplant adult recipients of liver transplantation

Hepatitis C recurrence continues to present a major challenge in liver transplantation (LT). Approximately 10% of hepatitis C virus (HCV)-positive recipients will develop fibrosing cholestatic hepatitis (FCH) after LT. FCH is clinically characterized as marked jaundice with cholestatic hepatic dysfunction and high titers of viremia. Pathologically, FCH manifests as marked hepatocyte swelling, cholestasis, periportal peritrabecular fibrosis and only mild inflammation. This progressive form usually involves acute liver failure, and rapidly results in graft loss. A real-time and precise diagnosis based on histopathological examination and viral measurement is indispensable for the adequate treatment of FCH. Typical pathological findings of FCH are shown. Currently, carefully selected combinations of direct-acting antivirals (DAAs) offer the potential for highly effective and safe regimens for hepatitis C, both in the pre- and post-transplant settings. Here, we review FCH caused by HCV in LT recipients, and current strategies for sustained virological responses after LT. Only a few cases of successfully treated FCH C after LT by DAAs have been reported. The diagnostic findings and therapeutic dilemma are discussed based on a literature review.

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.

The Correlation of Hepatic and Systemic Hemodynamics During Liver Transplantation: Quantification of Hepatic Resistance as an Actual Value

The correlation between portal vein pressure (PVP) and flow (PVF) has not been established, and there is still lack of consensus about the optimal hemodynamics during liver transplantation (LT). We aimed to establish the correlation between systemic and hepatic hemodynamics during LT by applying the hepatokinetic power hypothesis, based on the law of energy conservation and hydrodynamics.A total of 103 adult liver transplant recipients were enrolled in this study from September 2012 to December 2014. Systemic and hepatic hemodynamics were assessed intraoperatively to calculate the hepatokinetic power status. Severe surgical complications (Clavien-Dindo grade ≥III) were recorded as the main outcome measure, and potential covariates were evaluated including recipient, donor, donor-recipient match, surgery-related factors, conventional hemodynamics, and the intraoperative hepatokinetic power profile.In multivariate analysis, hepatokinetic power gradient >4260 mL mmHg min100 g graft weight (P = 0.001), 2.2 < ratio of hepatokinetic power from the portal vein to the hepatic artery ≤8.7 (P = 0.012), and hepatic resistance of partial grafts ≤0.006 or >0.015 min mmHg mL (P = 0.012) were associated with a higher risk. None of the conventional hemodynamic parameters, such as PVP, PVF, and hepatic venous pressure gradient, entered into this regression model (c-statistic = 0.916) when competing with hepatokinetic power indexes.The hepatokinetic power hypothesis clarifies the correlation of systemic and hepatic hemodynamics in a simple, rational manner. The hepatic resistance, derived from the hepatokinetic power equation, can be quantified and has an effect on the incidence of severe surgical complications. This finding offers a new objective clinical approach to evaluate graft quality during transplantation.

Incidence and risk factors for herpes zoster in patients undergoing liver transplantation

BACKGROUND

Herpes zoster (HZ) is the most common manifestation of latent varicella zoster virus reactivation, which occurs naturally as a result of aging or in immunocompromised patients. Solid organ transplant recipients are at increased risk for HZ owing to their chronic immunosuppression. Although several reports investigated risk factors for the development of HZ in heart or renal transplantation, data in liver transplantation (LT) are limited.

METHODS

We evaluated clinical data retrospectively in 377 adult patients undergoing LT between January 2005 and December 2012 in our institution. We analyzed the incidence rate of HZ and the standardized incidence ratio (SIR) by comparing with the general Japanese population. We additionally investigated risk factors for HZ after LT.

RESULTS

HZ developed in 27 (7.16%) of the 377 patients after LT. The incidence rate of HZ after LT was 17.83 per 1000 person-years, which was significantly higher than in the general Japanese population (SIR = 4.61; 95% confidence interval [CI], 4.13-5.14). Multivariate analysis showed that older age (hazard ratio [HR] = 3.95; P < 0.001) and exposure to mycophenolate mofetil (HR = 3.03; P = 0.007) were independent risk factors for HZ after LT.

CONCLUSIONS

This is the first and largest study, to our knowledge, to investigate the incidence rate of HZ and risk factors for development of HZ after LT in the Japanese population. Further investigations to focus on immunosuppressive regimens to reduce the risk for HZ incidence in this high-risk population could establish a new protocol of immunosuppression after LT.

Hepatic hemodynamic changes during liver transplantation: A review

Liver transplantation is performed in the recent decades with great improvements not only technically but also conceptually. However, there is still lack of consensus about the optimal hemodynamic characteristics during liver transplantation. The representative hemodynamic parameters include portal vein pressure, portal vein flow, and hepatic venous pressure gradient; however, there are still others potential valuable parameters, such as total liver inflow and hepatic artery flow. All the parameters are correlated closely and some internal modulating mechanisms, like hepatic arterial buffer response, occur to maintain stable hepatic inflow. To distinguish the unique importance of each hepatic and systemic parameter in different states during liver transplantation, we reviewed the published data and also conducted two transplant cases with different surgical strategies applied to achieve ideal portal inflow and pressure.

Green light for liver function monitoring using indocyanine green? An overview of current clinical applications

The dye indocyanine green is familiar to anaesthetists, and has been studied for more than half a century for cardiovascular and hepatic function monitoring. It is still, however, not yet in routine clinical use in anaesthesia and critical care, at least in Europe. This review is intended to provide a critical analysis of the available evidence concerning the indications for clinical measurement of indocyanine green elimination as a diagnostic and prognostic tool in two areas: its role in peri-operative liver function monitoring during major hepatic resection and liver transplantation; and its role in critically ill patients on the intensive care unit, where it is used for prediction of mortality, and for assessment of the severity of acute liver failure or that of intra-abdominal hypertension. Although numerous studies have demonstrated that indocyanine green elimination measurements in these patient populations can provide diagnostic or prognostic information to the clinician, 'hard' evidence - i.e. high-quality prospective randomised controlled trials - is lacking, and therefore it is not yet time to give a green light for use of indocyanine green in routine clinical practice.

Oxidative stress and extracellular matrices after hepatectomy and liver transplantation in rats

AIM: To investigate oxidative stress (OS)-mediated damage and the behavior of extracellular matrices in various rat models because shear stress with portal hypertension and cold ischemia/warm reperfusion injury trigger the liver regeneration cascade after surgery. These injuries also cause fatal liver damage.

METHODS: Rats were divided into four groups according to the surgery performed: control; hepatectomy with 40% liver remnant (60% hepatectomy); orthotopic liver transplantation (OLT) with whole liver graft (100% OLT); and split OLT (SOLT) with 40% graft (40% SOLT). Survival was evaluated. Blood and liver samples were collected at 6 h after surgery. Biochemical and histopathological examinations were performed. OS-induced damage, 4-hydroxynonenal, ataxia-telangiectasia mutated kinase, histone H2AX, phosphatidylinositol 3-kinase (PI3K) and Akt were evaluated by western blotting. Behavior of extracellular matrices, matrix metalloproteinase (MMP)-9, MMP-2, tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2 were also evaluated by western blotting and zymography.

RESULTS: Although 100% OLT survived, 60% hepatectomy and 40% SOLT showed poor survival. Histopathological, immunohistological, biochemical and protein assays revealed that 60% hepatectomy, 100% OLT and 40% SOLT showed liver damage. PI3K and Akt were decreased in 60% hepatectomy and 40% SOLT. For protein expression, 40% SOLT showed differences in MMP-9, MMP-2 and TIMP-2. TIMP-1 showed differences in 60% hepatectomy and 40% SOLT. For protein activity, MMP-9 demonstrated significant differences in 60% hepatectomy, 100% OLT and 40% SOLT.

CONCLUSION: Under conditions with an insufficient liver remnant, prevention of OS-induced damage via the Akt/PI3K pathway may be key to improve the postoperative course. MMP-9 may be also a therapeutic target after surgery.

How do transplant surgeons accomplish optimal portal venous flow during living-donor liver transplantation? Noninvasive measurement of indocyanine green elimination rate

BACKGROUND

Balancing donor safety and graft volume is difficult. We previously reported that intentional modulation of portal venous pressure (PVP) during living-donor liver transplantation (LDLT) is crucial to overcoming problems with small-for-size grafts; however, detailed studies of portal venous flow (PVF) and a reliable parameter are still required.

PATIENTS AND METHODS

The elimination rate (k) of indocyanine green (ICG) was measured in 49 adult LDLT recipients. PVP was controlled during LDLT, with a target of <20 mm Hg. ICG reflects hepatocyte volume and effective PVF. The kICG value is divided by the graft weight to calculate PVF. Recipients were divided into 2 groups: those with severe and/or fatal complications within 1 month after LDLT and those without.

RESULTS

Survival rates and postoperative profiles were significantly different between the 2 groups. Univariate analysis showed significant differences in ABO blood group, final PVP, final kICG, and the final kICG/graft weight value; however, multivariate analysis showed that only the kICG/graft weight value was significant. The cutoff level for the final kICG/graft weight value for predicting successful LDLT was 3.1175 × 10(-4)/g.

CONCLUSION

Accurate evaluation and monitoring of optimal PVF during LDLT should overcome the use of small-for-size grafts and improve donor safety and recipient outcomes.

Small-for-size syndrome in living donor liver transplantation

When the graft volume is too small to satisfy the recipient's metabolic demand, the recipient may thus experience small-for-size syndrome (SFSS). Because the occurrence of SFSS is determined by not only the liver graft volume but also a combination of multiple negative factors, the definitions of small-for-size graft (SFSG) and SFSS are different in each institute and at each time. In the clinical setting, surgical inflow modulation and maximizing the graft outflow are keys to overcoming SFSS. Accordingly, relatively smaller-sized grafts can be used with surgical modification and pharmacological manipulation targeting portal circulation and liver graft quality. Therefore, the focus of the SFSG issue is now shifting from how to obtain a larger graft from the living donor to how to manage the use of a smaller graft to save the recipient, considering donor safety to be a priority.