Current concept of small-for-size grafts in living donor liver transplantation

Successful Simultaneous Subtotal Splenectomy During Left Lobe Auxiliary Liver Transplantation for Portal Inflow Modulation and Severe Hypersplenism Correction: A Case Report

Adult-to-adult living donor liver transplantation with small partial liver grafts often requires intraoperative portal inflow modulation to prevent portal hyperperfusion and subsequent small-for-size syndrome (SFSS). However, there are concerns about the specific morbidity of these modulation techniques. This study aims to lower post-perfusion portal venous pressure and correct severe hypersplenism in a patient with end-stage liver cirrhosis by simultaneous subtotal splenectomy during auxiliary partial orthotopic liver transplantation (APOLT). A 29-year-old man was diagnosed with cryptogenic cirrhosis and severe portal hypertension suffered recurrent acute variceal bleeding, severe thrombocytopenia, and massive ascites before admission to our hospital. After the recipient's left liver was resected, we performed APOLT using his 51-year-old father's left lobe graft with a graft-to-recipient weight ratio of 0.55%. Intraoperatively, simultaneous subtotal splenectomy was performed to lower graft post-perfusion portal vein pressure below 15 mmHg and correct severe hypersplenism-related pancytopenia. The recipient's postoperative hospital course was uneventful with no occurrence of SFSS and procedure-related complications. Platelet and leukocyte counts remained in the normal ranges postoperatively. The living donor was discharged 6 days after the operation and recovered well-with no complications. After a follow-up period of 35.3 months, both the recipient and donor live with good liver function and overall condition. This is the first case report of simultaneous subtotal splenectomy during APOLT using small-for-size living-donated left liver lobes, which is demonstrated to be a viable procedure for modulating portal inflow and correcting severe hypersplenism in selected adult patients with end-stage liver cirrhosis. APOLT using a small-for-size liver graft may be a safe and feasible treatment option for selected adult patients with end-stage liver cirrhosis.

Pretransplantation splenomegaly frequently persists after liver transplantation and can manifest as hypersplenism and graft fibrosis - a retrospective study

The risk factors and clinical impact of post-transplantation splenomegaly (SM) are poorly understood. We investigated the predictors and impacts of post-transplantation SM in 415 LT patients at Kyoto University Hospital from April 2006 to December 2015. First, the predictors and clinical consequences of SM three years post-transplantation were analyzed among spleen-preserved recipients. Second, the clinical data of surviving recipients three years post-transplantation were compared between splenectomized and spleen-preserved recipients. There was no difference in indication for liver transplantation between these two groups. Third, survival outcomes were compared between splenectomized and spleen-preserved recipients. SM was determined as a SV/body surface area (BSA) higher than 152 ml/m² . In the first analysis, preoperative SM occurred in 79.9% recipients and SM persisted three years post-transplantation in 72.6% recipients among them. Preoperative SV/BSA was the only independent predictor of three year post-transplantation SM, which was associated with lower platelet (PLT), white blood cell (WBC) counts and significant graft fibrosis (21.4% vs. 2.8%). In the second analysis, spleen-preservation was related to lower PLT, WBC counts and a higher proportion of significant graft fibrosis (26.7% vs. 7.1%) three years post-transplantation. In the third analysis, spleen-preserved recipients showed worse survival than splenectomized recipients. In conclusion, preoperative SM frequently persists more than three years post-transplantation and is associated with subclinical hypersplenism, graft fibrosis, graft loss, and even death.

Pediatric living donor left lateral segment liver transplantation for biliary atresia: Doppler ultrasound findings in early postoperative period

PURPOSE

To analyze hepatic hemodynamic parameters detected by Doppler ultrasound (DU) of uncomplicated children with biliary atresia who underwent left lateral segment living donor liver transplantation (LLS-LDLT), explore its normal change trend over time and determine the normal reference interval.

METHODS

We retrospectively involved the data from 227 biliary atresia patients (100 Males,127 Females). Hemodynamic parameters include peak systolic velocity (PSV), end-diastolic velocity (EDV), resistivity index (RI), and pulsation index (PI) of the hepatic artery (HA), portal vein velocity (PVV), portal vein flow (PVF) and hepatic vein velocity (HVV) during intra-operative and on the 1st, 3rd, 5th and 7th day after operation were collected. Repeated measures analysis of the variance and Friedman test were used to analyze the changing trend of hemodynamic parameters over time in the first week after the operation.

RESULTS

PSV_HA and EDV_HA showed a similar changing tendency at one week after surgery, with an overall decrease-rise trend; RI_HA and PI_HA also changed similarly with an overall rise-decrease trend. The HVV and PVV at surgery were lower than at all time points after surgery. As for PVF, the value of POD5 was the highest and then decreased. Additionally, this study provided the normal reference interval of hemodynamic parameters for LLS-LDLT patients, which were PSV_HA: 18.4-98.3 cm/s, EDV_HA: 0-43.3 cm/s, RI_HA: 0.41-1.0, PI_HA: 0.51-2.0, PVV: 19.0-83.7 cm/s, HVV: 19.4-68.0 cm/s, and PVF:99.5-500.0 ml/min/100 g at intraoperation. Within the first postoperative week: PSV_HA: 21.0-97.7 cm/s, EDV_HA: 0-32.7 cm/s, RI_HA: 0.47-1.0, PI_HA: 0.62-2.0, PVV: 23.0-92.0 cm/s, HVV: 19.7-86.0 cm/s, and PVF: 100.0-513.0 ml/min/100 g.

CONCLUSION

The hepatic hemodynamic of post-transplanted children detected by DU had specific changing trends and normal ranges, which provides valuable reference values for ultrasonologists and pediatric transplant clinicians.

Small-for-size graft, small-for-size syndrome and inflow modulation in living donor liver transplantation

The extended application of living donor liver transplantation (LDLT) has revealed the problem of graft size mismatching called "small-for-size syndrome (SFSS)." The initial trials to resolve this problem involved increasing the procured graft size, from left to right, and even extending to include a right lobe graft. Clinical cases of living right lobe donations have been reported since then, drawing attention to the risks of increasing the liver volume procured from a living donor. However, not only other modes of increasing graft volume (GV) such as auxiliary or dual liver transplantation, but also control of the increased portal pressure caused by a small-for-size graft (SFSG), such as a porto-systemic shunt or splenectomy and optimal outflow reconstruction, have been trialed with some positive results. To establish an effective strategy for transplanting SFSG and preventing SFSS, it is essential to have precise knowledge and tactics to evaluate graft quality and GV, when performing these LDLTs with portal pressure control and good venous outflow. Thus, we reviewed the updated literature on the pathogenesis of and strategies for using SFSG.

Liver regeneration after performing associating liver partition and portal vein occlusion for staged hepatectomy (ALPPS) is histologically similar to that occurring after liver transplantation using a small-for-size graft

PURPOSE

Associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) can achieve marked future liver remnant (FLR) hypertrophy but this procedure is associated with a risk of mortality due to liver failure because of an insufficient FLR functional increase, a situation comparable to small-for-size syndrome (SFSS) after living-donor liver transplantation (LDLT).

METHODS

The clinical data, morphologic volume changes, and histopathologic and immunohistochemical findings in hepatocytes and bile ductules were compared between ALPPS (n = 10) and LDLT with a risk for SFSS (n = 12).

RESULTS

Although the patient characteristics and short-term outcome differed between the groups, the mean hypertrophy ratios with respect to liver volume for the FLR after performing the first-stage ALPPS procedures resembled those in small-for-size grafts after similar time intervals: 1.702 ± 0.407 in ALPPS vs. 1.948 ± 0.252 in LDLT (P = 0.205). The histologic grades for sinusoidal dilation (P = 0.896), congestion (P = 0.922), vacuolar change (P = 0.964), hepatocanalicular cholestasis (P = 0.969), and ductular reaction (P = 0.728) within the FLR at the second-stage operation during ALPPS or implanted graft were all similar between the groups.

CONCLUSIONS

The hepatic regenerative process may be similar in ALPPS and LDLT using a small-for-size graft. Reducing the hepatic vascular inflow that may be excessive for the FLR volume during the first stage of ALPPS might enhance the functional recovery since measures with a similar effect appear to lessen the likelihood of SFSS.

Conceptual changes in small-for-size graft and small-for-size syndrome in living donor liver transplantation

Early series in living donor liver transplantation (LDLT) in adults demonstrated a lower safe limit of graft volume standard liver volume ratio 25%–45%. A subsequent worldwide large LDLT series proposed a 0.8 graft recipient weight ratio (GRWR) to define small-for-size graft (SFSG) in adult LDLT. Thereafter, researchers identified innate and inevitable factors including changes in liver volume during imaging studies and graft shrinkage due to perfusion solution. Although the definition of small-for-size syndrome (SFSS) advocated in the 2000s was mainly based on prolonged cholestasis and ascites output, the term SFSS was inadequate to describe clinical manifestations possibly caused by multiple factors. Thus, the term “early allograft dysfunction (EAD),” characterized by total bilirubin >10 mg/dL or coagulopathy with international normalized ratio >1.6 on day 7, has become prevalent to describe graft dysfunction including SFSS after LDLT. Although various efforts have been made to overcome EAD in LDLT, graft selection to maintain an expected GRWR >0.8 and full venous drainage, as well as inflow modulation using splenic artery ligation, have become standard in recent LDLT.

Right anterior section graft for living-donor liver transplantation: A case report

RATIONALE

In living-donor liver transplantation (LDLT), the right lobe graft is commonly utilized to prevent small-for-size syndrome, despite the considerable donor morbidity. Conversely, the feasibility of the left lobe graft and the right posterior section graft in smaller-sized recipients is now commonly employed with comparable outcomes to right lobe grafts. The efficacy of the right anterior section graft has rarely been reported.

PATIENT CONCERNS

A 56-year-old man, a heavy alcoholic beverage drinker for 20 years, presented in the emergency department with massive ascites and lethargy. He was previously admitted twice due to bleeding esophageal varices.

DIAGNOSIS

He was diagnosed with hepatic encephalopathy coma due to alcoholic liver cirrhosis. The Child-Turcotte-Pugh score was 11 (class C), and the Model for End-stage Liver Disease score was 21.62.

INTERVENTION

A LDTL was offered to the patient as the best treatment option available. The patient's 26-year-old son was found to be the only donor-compatible candidate for the LDTL.Preoperatively, the right lobe of the donor occupied 76.2% of the total liver volume exposing the donor to a small residual liver volume. The right posterior section and left lobe volumes were insufficient, providing a graft-to-recipient weight ratio of 0.42% and 0.38%, respectively. However, the right anterior section could fulfill an acceptable GRWR of 0.83%. Thus, a living donor right anterior sectionectomy was performed.

OUTCOMES

Clinical signs and symptoms and liver function improved following anterior section graft transplantation without complications.

LESSON

The procurement of anterior section graft is technically feasible in selected patients, especially in high-volume liver centers.

A Lipidomics Study Reveals Lipid Signatures Associated with Early Allograft Dysfunction in Living Donor Liver Transplantation

Liver transplantation has become the ultimate treatment for patients with end stage liver disease. However, early allograft dysfunction (EAD) has been associated with allograft loss or mortality after transplantation. We aim to utilize a metabolomic platform to identify novel biomarkers for more accurate correlation with EAD using blood samples collected from 51 recipients undergoing living donor liver transplantation (LDLT) by 1H-nuclear magnetic resonance spectroscopy (NMR) and liquid chromatography coupled with mass spectrometry (LC-MS). Principal component analysis (PCA) and orthogonal projection to latent structures-discriminant analysis (OPLS-DA) were used to search for a relationship between the metabolomic profiles and the presence of EAD.Cholesteryl esters (CEs), triacylglycerols (TGs), phosphatidylcholines (PCs) and lysophosphatidylcholine (lysoPC) were identified in association with EAD and a combination of cholesterol oleate, PC (16:0/16:0), and lysoPC (16:0) gave an optimal area under the curve (AUC) of 0.9487 and 0.7884 in the prediction of EAD and in-hospital mortality, respectively after LDLT. Such biomarkers may add as a potential clinical panel for the prediction of graft function and mortality after LDLT.

Evaluation of postoperative ascites after somatostatin infusion following hepatectomy for hepatocellular carcinoma by laparotomy: a multicenter randomized double-blind controlled trial (SOMAPROTECT)

Background

The majority of patients undergoing hepatectomy for hepatocellular carcinoma (HCC) suffer from underlying liver disease and are exposed to the risk of postoperative ascites, which is favored by an imbalance between portal venous inflow and a diminished hepatic volume. Finding a reversible, non-invasive method for modulating the portal inflow would be of interest as it could be used temporarily during the early postoperative course. Somatostatin, a well-known drug already used in several indications, may limit the risk of postoperative ascites and liver failure by decreasing portal pressure after hepatectomy for HCC in patients with underlying liver disease. We aimed to evaluate the impact of somatostatin postoperative infusion on the incidence of ascites following hepatectomy by laparotomy for HCC in patients with underlying liver disease.

Methods/design

The SOMAPROTECT study is a multicenter randomized double-blind placebo controlled phase III trial comparing two arms of patients with underlying liver disease undergoing hepatectomy for HCC by open approach. All patients will have primary abdominal drainage before closure. Patients in the experimental arm will receive a postoperative intravenous infusion of somatostatin during 6 days. Patients in the control group will receive a placebo infusion for the same duration. The primary endpoint will be the presence or absence of postoperative ascites occurring during the 90-day postoperative course, defined as ≥500 ml/24 h of fluid in the drains during at least 3 days or any ascites requiring an invasive procedure comprising percutaneous puncture or drainage. Secondary endpoints will be duration and total volume of ascites, postoperative 90-day mortality and morbidity, liver failure, acute renal failure, length of stay in intensive care unit and hospital stay. The total number of patients to be enrolled was calculated to be 152.

Discussion

Postoperative ascites remains a major issue after hepatectomy for HCC as it is associated with increased morbidity, liver and renal failure, the need for specific treatments and prolonged hospital stay. This study represents the first randomized controlled trial to assess the benefits of somatostatin on the risk of postoperative ascites after surgery for HCC.

Trial registration

NCT02799212 (ClinicalTrials.gov identifier). Registered prior to conducting the research on 9 June 2016.

Living Donor Liver Transplantation Using Small-for-Size Grafts: Does Size Really Matter?

BACKGROUND

In living donor liver transplantation (LDLT), graft-to-recipient weight ratio (GRWR) > 0.8% is perceived as the critical graft size. This lower limit of GRWR (0.8%) has been challenged over the last decade owing to the surgical refinements, especially related to inflow and outflow modulation techniques. Our aim was to compare the recipient outcome in small-for-size (GRWR < 0.8) versus normal-sized grafts (GRWR > 0.8) and to determine the risk factors for mortality when small-for-size grafts (SFSG) were used.

METHODS

Data of 200 transplant recipients and their donors were analyzed over a period of two years. Routine practice of harvesting middle hepatic vein (MHV) or reconstructing anterior sectoral veins into neo-MHV was followed during LDLT. Outcomes were compared in terms of mortality, hospital stay, ICU stay, and occurrence of various complications such as functional small-for-size syndrome (F-SFSS), hepatic artery thrombosis (HAT), early allograft dysfunction (EAD), portal vein thrombosis (PVT), and postoperative sepsis. A multivariate analysis was also done to determine the risk factors for mortality in both the groups.

RESULTS

Recipient and donor characteristics, intraoperative variables, and demographical data were comparable in both the groups (GRWR < 0.8 and GRWR ≥ 0.8). Postoperative 90-day mortality (15.5% vs. 22.85%), mean ICU stay (10 vs. 10.32 days), and mean hospital stay (21.4 vs. 20.76 days) were statistically similar in the groups. There was no difference in postoperative outcomes such as occurrence of SFSS, HAT, PVT, EAD, or sepsis between the groups. Thrombosis of MHV/reconstructed MHV was a risk factor for mortality in grafts with GRWR < 0.8 but not in those with GRWR > 0.8.

CONCLUSION

Graft survival after LDLT using a small-for-size right lobe graft (GRWR < 0.8%) is as good as with normal grafts. However, patency of anterior sectoral outflow by MHV or reconstructed MHV is crucial to maintain graft function when SFSG are used.

Small for size syndrome difficult dilemma: Lessons from 10 years single centre experience in living donor liver transplantation

AIM

To analyze the incidence, risk factors, prevention, treatment and outcome of small for size syndrome (SFSS) after living donor liver transplantation (LDLT).

METHODS

Through-out more than 10 years: During the period from April 2003 to the end of 2013, 174 adult-to-adults LDLT (A-ALDLT) had been performed at National Liver Institute, Menoufiya University, Shibin Elkoom, Egypt. We collected the data of those patients to do this cohort study that is a single-institution retrospective analysis of a prospectively collected database analyzing the incidence, risk factors, prevention, treatment and outcome of SFSS in a period started from the end of 2013 to the end of 2015. The median period of follow-up reached 40.50 m, range (0-144 m).

RESULTS

SFSS was diagnosed in 20 (11.5%) of our recipients. While extra-small graft [small for size graft (SFSG)], portal hypertension, steatosis and left lobe graft were significant predictors of SFSS in univariate analysis (P = 0.00, 0.04, 0.03, and 0.00 respectively); graft size was the only independent predictor of SFSS on multivariate analysis (P = 0.03). On the other hand, there was lower incidence of SFSS in patients with SFSG who underwent splenectomy [4/10 (40%) SFSS vs 3/7 (42.9%) no SFSS] but without statistical significance, However, there was none significant lower incidence of the syndrome in patients with right lobe (RL) graft when drainage of the right anterior and/or posterior liver sectors by middle hepatic vein, V5, V8, and/or right inferior vein was done [4/10 (28.6%) SFSS vs 52/152 (34.2%) no SFSS]. The 6-mo, 1-, 3-, 5-, 7- and 10-year survival in patients with SFSS were 30%, 30%, 25%, 25%, 25% and 25% respectively, while, the 6-mo, 1-, 3-, 5-, 7- and 10-year survival in patients without SFSS were 70.1%, 65.6%, 61.7%, 61%, 59.7%, and 59.7% respectively, with statistical significant difference (P = 0.00).

CONCLUSION

SFSG is the independent and main factor for occurrence of SFSS after A-ALDLT leading to poor outcome. However, the management of this catastrophe depends upon its prevention (i.e., selecting graft with proper size, splenectomy to decrease portal venous inflow, and improving hepatic vein outflow by reconstructing large draining veins of the graft).

Small for size syndrome difficult dilemma: Lessons from 10 years single centre experience in living donor liver transplantation

AIM

To analyze the incidence, risk factors, prevention, treatment and outcome of small for size syndrome (SFSS) after living donor liver transplantation (LDLT).

METHODS

Through-out more than 10 years: During the period from April 2003 to the end of 2013, 174 adult-to-adults LDLT (A-ALDLT) had been performed at National Liver Institute, Menoufiya University, Shibin Elkoom, Egypt. We collected the data of those patients to do this cohort study that is a single-institution retrospective analysis of a prospectively collected database analyzing the incidence, risk factors, prevention, treatment and outcome of SFSS in a period started from the end of 2013 to the end of 2015. The median period of follow-up reached 40.50 m, range (0-144 m).

RESULTS

SFSS was diagnosed in 20 (11.5%) of our recipients. While extra-small graft [small for size graft (SFSG)], portal hypertension, steatosis and left lobe graft were significant predictors of SFSS in univariate analysis (P = 0.00, 0.04, 0.03, and 0.00 respectively); graft size was the only independent predictor of SFSS on multivariate analysis (P = 0.03). On the other hand, there was lower incidence of SFSS in patients with SFSG who underwent splenectomy [4/10 (40%) SFSS vs 3/7 (42.9%) no SFSS] but without statistical significance, However, there was none significant lower incidence of the syndrome in patients with right lobe (RL) graft when drainage of the right anterior and/or posterior liver sectors by middle hepatic vein, V5, V8, and/or right inferior vein was done [4/10 (28.6%) SFSS vs 52/152 (34.2%) no SFSS]. The 6-mo, 1-, 3-, 5-, 7- and 10-year survival in patients with SFSS were 30%, 30%, 25%, 25%, 25% and 25% respectively, while, the 6-mo, 1-, 3-, 5-, 7- and 10-year survival in patients without SFSS were 70.1%, 65.6%, 61.7%, 61%, 59.7%, and 59.7% respectively, with statistical significant difference (P = 0.00).

CONCLUSION

SFSG is the independent and main factor for occurrence of SFSS after A-ALDLT leading to poor outcome. However, the management of this catastrophe depends upon its prevention (i.e., selecting graft with proper size, splenectomy to decrease portal venous inflow, and improving hepatic vein outflow by reconstructing large draining veins of the graft).

Modified ALPPS Procedures Avoiding Division of Portal Pedicles

OBJECTIVE

We describe a modified procedure associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) including portal pedicle preservation during parenchymal division, thus avoiding necrosis.

BACKGROUND

Although ALPPS recently has been advocated for treating advanced liver tumors, sepsis originating from the ischemic area produced by parenchymal division increases mortality, accounting for one-third of postoperative deaths.

METHODS

Our procedure differs from the original ALPPS technique by sparing portal pedicles at the transection plane, thus maintaining blood supply. The preserved pedicles are segment 4 (S4) in right lobectomy plus right portal vein ligation (PVL), S1 in extended right hepatectomy (extended to S1) plus right PVL, lateral portal pedicles of the right paramedian sector (RPS) in extended right lateral sectoriectomy plus lateral PVL, and both portal pedicles of the lateral RPS and S1 in extended right lateral sectoriectomy with S1 resection plus lateral PVL.

RESULTS

These procedures were performed in 5 patients. Morbidity rates at first- and second-stage operations were 0% and 80%, without mortality. Mean hypertrophy of the future liver remnant was 1.638 ± 0.384 a week after the first-stage procedure.

CONCLUSIONS

Our technique stimulates rapid hypertrophy and may improve safety in ALPPS.

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.

Renoportal anastomosis in living donor liver transplantation with prior proximal splenorenal shunt

For transplant surgeons, end-stage liver disease with portal venous thrombosis and a previous splenorenal shunt (SRS) is a significant challenge during liver transplantation. Thrombosis of the portal vein can be corrected by surgical interventions, such as portal venous thrombectomy or surgical removal of the thrombosed portal vein. Even also placement of a graft between the mesenteric vein and the graft portal vein can be performed. If these maneuvers fail, a renoportal anastomosis (RPA) can be performed to achieve adequate graft inflow. A 51-year-old male patient who had a history of proximal SRS and splenectomy underwent living donor liver transplantation (LDLT) due to cryptogenic cirrhosis. LDLT was performed with RPA using a cadaveric iliac vein graft. The early postoperative course of the patient was completely uneventful and he was discharged 20 d after transplantation. To the best of our knowledge, this was the first patient to receive LDLT with RPA after surgical proximal SRS and splenectomy.

The outcomes of pediatric living donor liver transplantation using small-for-size grafts: experience of a single institute

PURPOSE

We aimed to evaluate patients who had undergone pediatric LDLT with small-for-size graft (SFSG) and identify risk factors of graft failure to establish a preoperative graft selection strategy.

METHODS

The data was collected retrospectively. SFSG was used in 14LDLTs (5.7%) of 245 LDLTs performed between May 2001 and March 2014. The mean patient age and body weight at LDLT were 12.6 ± 2.0 years and 40.5 ± 9.9 kg, respectively. The graft type was left lobe in six patients, left + caudate lobe in seven patients, and posterior segment in one patient.

RESULTS

The graft survival rates in SFSG and non-SFSG groups were 78.9 and 93.1%, respectively (p = 0.045). In the univariate analysis, bleeding volume during LDLT were an independent risk factors for graft failure (p = 0.011). Graft failure was caused by sepsis in all three patients and occurred at a median of 70 postoperative days 70 (range 14-88 days). Among them, two cases showed high preoperative PELD/MELD score (PELD; 19.4 and MELD; 22, respectively).

CONCLUSIONS

Pediatric LDLT using SFSG had poor outcome and prognosis, especially when it accompanies the surgical infectious complications with preoperative high PELD/MELD scores.

Wnt agonist stimulates liver regeneration after small-for-size liver transplantation in rats

AIM

Liver regeneration is inhibited in small-for-size grafts, which plays a role in the failure of partial liver grafts after transplantation. The Wnt/β-catenin signaling pathway plays a critical role in liver development, regeneration and homeostasis. In this study, we investigated whether pharmacological activation of Wnt signaling improves liver regeneration after small-for-size liver transplantation.

METHODS

The livers of male Sprague-Dawley rats were reduced to approximately 50% and 30% of their original sizes and transplanted. A Wnt agonist (2-amino-4-[3,4-[methylenedioxy]benzylamino]-6-[3-methoxyphenyl] pyrimidine], 5 mg/kg bodyweight) or an equal volume of vehicle was administrated i.p. into the donor 1 h before the transplantation. Tissue and blood samples were collected at various times after transplantation, and a survival study was performed.

RESULTS

Hepatic expression of active β-catenin and its downstream target gene Axin2 were decreased in 30% of liver grafts after transplantation while the Wnt agonist increased their expression similar to the 50% liver grafts. The Wnt agonist reversed inhibition of cyclin D1 expression and adenosine triphosphate production in the 30% liver grafts compared with the 50% grafts. The Wnt agonist also attenuated hepatocellular injury and increased the hepatocyte proliferation response, liver regeneration rate and survival after transplantation of the 30% liver graft.

CONCLUSION

Activation of Wnt/β-catenin signaling in liver grafts by pharmacological pretreatment can accelerate regeneration in a partial liver transplant model.

Subtotal hepatectomy in swine for studying small-for-size syndrome and portal inflow modulation: is it reliable?

BACKGROUND

Small-for-size syndrome (SFSS) is a feared complication of extended liver resection and partial liver transplantation. Swine models of extended hepatectomy have been developed for studying SFSS and its different treatment options. Although portal inflow modulation (PIM) by splenectomy or splenic artery ligation (SAL) has been proposed in humans to prevent SFSS, such procedures have not yet been evaluated in swine.

OBJECTIVES

The present study was designed to evaluate modifications in splanchnic haemodynamics yielded by extended hepatectomy with and without PIM in swine.

METHODS

Nineteen animals underwent 70% hepatectomy (H70, n = 7), 90% hepatectomy (H90, n = 7) or sham laparotomy (H0, n = 5). Haemodynamic measurements were performed at baseline, after hepatectomy and after PIM by SAL and splenectomy.

RESULTS

Portal vein flow increased after both H70 (273 ml/min/100 g versus 123 ml/min/100 g; P = 0.016) and H90 (543 ml/min/100 g versus 124 ml/min/100 g; P = 0.031), but the hepatic venous pressure gradient (HVPG) increased only after H90 (10.0 mmHg versus 3.7 mmHg; P = 0.016). Hepatic artery flow did not significantly decrease after either H70 or H90. In all three groups, neither splenectomy nor SAL induced any changes in splanchnic haemodynamics.

CONCLUSIONS

Subtotal hepatectomy of 90% in swine is a reliable model for SFSS inducing a significant increase in HVPG. However, in view of the relevant differences between swine and human splanchnic anatomy, this model is inadequate for studying the effects of PIM by SAL and splenectomy.

Clinical implications of advances in liver regeneration

Remarkable advances have been made recently in the area of liver regeneration. Even though liver regeneration after liver resection has been widely researched, new clinical applications have provided a better understanding of the process. Hepatic damage induces a process of regeneration that rarely occurs in normal undamaged liver. Many studies have concentrated on the mechanism of hepatocyte regeneration following liver damage. High mortality is usual in patients with terminal liver failure. Patients die when the regenerative process is unable to balance loss due to liver damage. During disease progression, cellular adaptations take place and the organ microenvironment changes. Portal vein embolization and the associating liver partition and portal vein ligation for staged hepatectomy are relatively recent techniques exploiting the remarkable progress in understanding liver regeneration. Living donor liver transplantation is one of the most significant clinical outcomes of research on liver regeneration. Another major clinical field involving liver regeneration is cell therapy using adult stem cells. The aim of this article is to provide an outline of the clinical approaches being undertaken to examine regeneration in liver diseases.

Review of anesthesia in liver transplantation

Liver transplantation (LT) is a well-accepted treatment modality of many end-stage liver diseases. The main issue in LT is the shortage of deceased donors to accommodate the needs of patients waiting for such transplants. Live donors have tremendously increased the pool of available liver grafts, especially in countries where deceased donors are not common. The main ethical concern of this procedure is the safety of healthy donors, who undergo a major abdominal surgery not for their own health, but to help cure others. The first part of the review concentrates on live donor selection, preanesthetic evaluation, and intraoperative anesthetic care for living liver donors. The second part reviews patient evaluation, intraoperative anesthesia monitoring, and fluid management of the recipient. This review provides up-to-date information to help improve the quality of anesthesia, and contribute to the success of LT and increase the long-term survival of the recipients.

Small for size liver remnant following resection: prevention and management

In the latest decades an important change was registered in liver surgery, however the management of liver cirrhosis or small size hepatic remnant still remains a challenge. Currently post-hepatectomy liver failure (PLF) is the major cause of death after liver resection often associated with sepsis and ischemia-reperfusion injury (IRI). ''Small-for-size'' syndrome (SFSS) and PFL have similar mechanism presenting reduction of liver mass and portal hyper flow beyond a certain threshold. Few methods are described to prevent both syndromes, in the preoperative, perioperative and postoperative stages. Additionally to portal vein embolization (PVE), radiological examinations (mainly CT and/or MRI), and more recently 3D computed tomography are fundamental to quantify the liver volume (LV) at a preoperative stage. During surgery, in order to limit parenchymal damage and optimize regenerative capacity, some hepatoprotective measures may be employed, among them: intermittent portal clamping and hypothermic liver preservation. Regarding the treatment, since PLF is a quite complex disease, it is required a multi-disciplinary approach, where it management must be undertaken in conjunction with critical care, hepatology, microbiology and radiology services. The size of the liver cannot be considered the main variable in the development of liver dysfunction after extended hepatectomies. Additional characteristics should be taken into account, such as: the future liver remnant; the portal blood flow and pressure and the exploration of the potential effects of regeneration preconditioning are all promising strategies that could help to expand the indications and increase the safety of liver surgery.

Simultaneous splenectomy during liver transplantation augments anti-viral therapy in patients infected with hepatitis C virus

BACKGROUND

Simultaneous splenectomy in liver transplantation (LT) is selectively indicated because of splenoportal venous thromboses and increased sepsis. Therefore, its impact should be further investigated.

METHODS

Of the 160 liver transplant patients, only 40 underwent simultaneous splenectomy. Clinicopathologic characteristics and outcomes were compared between the splenectomy and non-splenectomy group using retrospective analysis.

RESULTS

Although the groups were similar and had no significant difference in the intra- and postoperative data, non-splenectomy group had more male patients. However, splenectomy group showed significantly higher platelet and leukocyte counts at 1 month and 6 months after the transplantation and higher hepatitis C virus anti-viral therapy completion. Furthermore, 3 patients developed portal or splenic vein thrombosis during the postoperative follow-up, but the overall survival rate did not significantly differ between these groups.

CONCLUSION

Simultaneous splenectomy in LT can be safely performed, particularly in patients with hepatitis C virus cirrhosis, small-for-size grafts, hypersplenism, and ABO blood group incompatible (ABO - incompatible) LT.

Outcome of patients undergoing right lobe living donor liver transplantation with small-for-size grafts

AIM: To investigate the outcome of living donor liver transplantation (LDLT) recipients transplanted with small-for-size grafts (SFSGs).

METHODS: Between November 2001 and December 2010, 196 patients underwent LDLT with right lobe liver grafts at our center. Recipients were divided into 2 treatment groups: group A with an actuarial graft-to-recipient weight ratio (aGRWR) < 0.8% (n = 45) and group B with an aGRWR ≥ 0.8% (n = 151). We evaluated serum liver function markers within 4 wk after transplantation. We also retrospectively evaluated the outcomes of these patients for potential effects related to the recipients, the donors and the transplantation procedures based upon a review of their medical records.

RESULTS: Small-for-size syndrome (SFSS) developed in 7 of 45 patients (15.56%) in group A and 9 of 151 patients (5.96%) in group B (P = 0.080). The levels of alanine aminotransferase and aspartate aminotransferase in group A were higher than those in group B during early period after transplantation, albeit not significantly. The cumulative 1-, 3- and 5-year liver graft survival rates were 82.22%, 71.11% and 71.11% for group A and 81.46%, 76.82%, and 75.50% for group B patients, respectively (P = 0.623). However, univariate analysis of risk factors associated with graft survival in group A demonstrated that the occurrence of SFSS after LDLT was the only significant risk factor affecting graft survival (P < 0.001). Furthermore, multivariate analysis of our data did not identify any additional significant risk factors accounting for poor graft survival.

CONCLUSION: Our study suggests that LDLT recipients with an aGRWR < 0.8% may have liver graft outcomes comparable to those who received larger size grafts. Further studies are required to ascertain the safety of using SFSGs.

Hemodynamic changes in the hepatic circulation after the modulation of the splenic circulation in an in vivo human experimental model

Recent advances in liver surgery have highlighted the effects of the splenic circulation on the hepatic circulation with respect to the hepatic arterial buffer response (HABR). The aim of the present study was to investigate the actual hemodynamic effects of splenic artery embolization/ligation and splenectomy on the hepatic circulation in patients who underwent pancreaticoduodenectomy through in vivo experimental models. In vivo models of splenic artery embolization/ligation (only splenic artery clamping) and splenectomy (simultaneous clamping of both the splenic artery and the splenic vein) were created in 40 patients who underwent pancreaticoduodenectomy for various reasons. The portal venous flow velocity, the portal venous flow volume, the hepatic arterial flow velocity, and the hepatic arterial resistance index were measured with color Doppler ultrasonography. Clamping of the splenic artery induced an immediate and significant increase (16%) in the hepatic artery velocity (P < 0.001), and the portal venous flow also decreased significantly (10%, P = 0.03). Fifteen minutes after the clamping of the splenic artery, the hepatic artery velocity remained significantly increased at the level of the initial clamping, and the portal venous flow significantly decreased (16%, P < 0.001). Clamping of the splenic vein, which was performed after the clamping of the splenic artery, resulted in an immediate and significant decrease (30%) in the portal venous flow (P < 0.001), but the hepatic arterial flow was not affected. Fifteen minutes after the clamping of the splenic vein, there was no change in the portal flow, which remained significantly lower (28%) than the flow in controls, whereas the hepatic arterial flow further significantly increased (31%, P < 0.001). In conclusion, our findings indicate that both splenic artery embolization/ligation and splenectomy are effective for increasing hepatic arterial flow and decreasing portal flow, with splenectomy providing a greater advantage. The HABR underlies these hemodynamic changes.

Effects of splenectomy on hepatic gene expression profiles after massive hepatectomy in rats

BACKGROUND AND AIM

Possible spleno-hepatic relationships affected by hepatectomy still remained unclear. We have previously reported that splenectomy may ameliorate liver injuries and promote appropriate liver regeneration after massive hepatectomy. Therefore, we investigated the effects of splenectomy on the DNA expression profile in the liver after massive hepatectomy in rats.

METHODS

Rats were divided into the following two groups: 90% hepatectomy (Hx group) and 90% hepatectomy with splenectomy (Hx + Sp group). Rats were sacrificed 3 and 6 h after surgery, and mRNA from liver tissue was isolated and hybridized to Affymetrix GeneChip Rat Genome 230 2.0 Array (Affymetrix, Santa Clara, CA, USA) and a pathway analysis was done with Ingenuity Pathway Analysis (Ingenuity Systems, Mountain View, CA, USA).

RESULTS

We determined the Hx + Sp/Hx ratio to assess the influence of splenectomy, and cut-off values were set at more than 2.0-fold or less than 1/2 (0.5)-fold. Immediate early response gene including early growth response-1 and FBJ murine osteosarcoma-related pathways were markedly downregulated by splenectomy. In contrast, heme oxygenase-1 gene-related pathway was upregulated by splenectomy.

CONCLUSIONS

Splenectomy provided the protective effects for liver failure and promoted liver regeneration, possibly owing to the downregulation of immediate early response genes and upregulation of the heat shock protein, heme oxygenase-1.

Surgical treatment for portosystemic encephalopathy in patients with liver cirrhosis: Occlusion of portosystemic shunt in combination with splenectomy

AIM

  Operative ligation of the portosystemic shunt may control hepatic encephalopathy effectively, but the subsequent increase in portal vein pressure (PVP) leads to high mortality. Splenectomy can decrease inflow into the portal system, resulting in decreased portal pressure.

METHODS

  We retrospectively examined the effect of splenectomy in combination with shunt closure on portosystemic encephalopathy.

RESULTS

  Clinical symptoms of encephalopathy disappeared in all six patients who underwent splenectomy in combination with portosystemic shunt ligation, with the exception of one patient who had relapsing encephalopathy after 6 months. Follow-up computed tomography showed complete obliteration of the portosystemic shunts, except in the one patient with relapsing encephalopathy who underwent balloon-occluded retrograde transvenous obliteration for the remaining splenorenal shunt 8 months after surgery. PVP significantly decreased after splenectomy. PVP did not increase to the baseline PVP value after ligation of the shunts, except in two patients who had elevated PVP after surgery: PVP increased from 18 to 19 mmHg after ligation in one patient and from 18 to 23 mmHg in one patient.

CONCLUSION

  Splenectomy followed by surgical ligation of the portosystemic shunt may be feasible and safe for cirrhotic patients with portosystemic shunts.

"Small-for-flow" syndrome: shifting the "size" paradigm

The "small-for-size" syndrome and "post-hepatectomy liver failure" refers to the development of liver failure (hyperbilirubinemia, coagulopathy, encephalopathy and refractory ascites) resulting from the reduction of liver mass beyond a certain threshold. This complication is associated with a high mortality and is a major concern in liver transplantation involving reduced liver grafts from deceased and living donors as well as in hepatic surgeries involving extended resections of liver mass. The limiting threshold for liver resection or transplantation is currently predicted based on the mass of the remnant liver (or donor graft) in relation to the body weight of the patient, with a ratio above 0.8 being considered safe. This approach, however, has proved inaccurate, because some patients develop the "small-for-size" syndrome despite complying with the "safe" threshold while other patients who surpass the threshold do not develop it. We hypothesize that the development of the "small-for-size" syndrome is not exclusively determined by the ratio of the mass of the liver remnant (or graft) to the body weight, but it is instead strictly determined by the hemodynamic parameters of the hepatic circulation. This hypothesis is based in recent clinical and experimental reports showing that relative portal hyperperfusion is a critical factor in the development of the "small-for-size" syndrome and that maneuvers that manipulate the hepatic vascular inflow are able to prevent the development of the syndrome despite liver-to-body weight ratios well below the "limiting" threshold. Measurements of hepatic blood flow and pressure, however, are not routinely performed in hepatic surgeries. Focusing on the "flow" rather than in the "size" may improve our understanding of the pathophysiology of the "small-for-size" syndrome and "post-hepatectomy liver failure" and it would have important implications for the clinical management of patients at risk. First, hepatic hemodynamic parameters would have to be measured in hepatic surgeries. Second, these parameters (in addition to liver mass) would be the principal basis for deciding the "safe" threshold of viable liver parenchyma. Third, the hepatic hemodynamic parameters are amenable to manipulation and, consequently, the "safe" threshold may also be manipulated. Shifting the paradigm from "small-for-size" to "small-for-flow" syndrome would thus represent a major step for optimizing the use of donor livers, for expanding the indications of hepatic surgery, and for increasing the safety of these procedures.

A novel organ preservation for small partial liver transplantations in rats: venous systemic oxygen persufflation with nitric oxide gas

The prognosis for recipients of small liver grafts is poor. The aim of this study was to determine the impact of venous systemic oxygen persufflation (VSOP) with nitric oxide (NO) gas for 30% partial liver preservation and transplantation in rats. After we determined optimal NO concentration as 40 ppm in vitro with the isolated perfused rat liver model, we assessed liver injury and regeneration in vivo at 1, 3, 24 and 168 h after transplantation in the following three groups after 3 h-cold storage (n = 20 per group): control group = static storage; VSOP group = oxygen persufflation and VSOP+NO group = oxygen with NO persufflation. The liver graft persufflation was achieved with medical gas via the suprahepatic vena cava; In comparison with control group after transplantation, VSOP+NO preservation (1) increased portal circulation, (2) reduced AST and ALT release, (3) upregulated hepatic endothelial NO synthase, (4) reduced hepatocyte and bileductule damage and (5) improved liver regeneration. These results suggest that gaseous oxygen with NO persufflation is a novel and safe preservation method for small partial liver grafts, not only alleviating graft injury but also improve liver regeneration after transplantation.

SOD mimetic improves the function, growth, and survival of small-size liver grafts after transplantation in rats

BACKGROUND

Small-for-size syndrome (SFSS) may occur when graft volume is less than 45% of the standard liver volume, and it manifests as retarded growth and failure of the grafts and more mortality. However, its pathogenesis is poorly understood, and few effective interventions have been attempted.

AIMS

The present study aimed to delineate the critical role of oxidant stress in SFSS and protective effects of a superoxide dismutase mimetic, Mn(III)tetrakis(4-benzoic acid)porphyrin chloride (MnTBAP), on graft function, growth, and survival in the recipient rats.

METHODS

Small size graft liver transplantation (SSGLT) was performed to determine the survival, graft injury, and growth. MnTBAP was administered in SSGLT recipients (SSGLT+MnTBAP).

RESULTS

Serum alanine aminotransferase levels were sustained higher in SSGLT recipients, which were correlated with an increased apoptotic cell count and hepatocellular necrosis in liver sections. Malondialdehyde content, gene expression of tumor necrosis factor α and interleukin 1β, and DNA binding activity of nuclear factor-κB in the grafts were increased significantly in SSGLT recipients compared with sham-operated controls. Both phosphorylated p38 mitogen-activated protein kinase and nuclear c-Jun were increased in SSGLT. All these changes were strikingly reversed by the administration of MnTBAP, with an increase in serum superoxide dismutase activity. Moreover, in situ bromodeoxyuridine incorporation demonstrated that graft regeneration was much more profound in the SSGLT+MnTBAP group than in the SSGLT group. Finally, the survival of recipients with MnTBAP treatments was significantly improved.

CONCLUSIONS

Enhanced oxidant stress with activation of the p38/c-Jun/nuclear factor-κB signaling pathway contributes to SFSS-associated graft failure, retarded graft growth, and poor survival. MnTBAP effectively reversed the pathologic changes in SFSS-associated graft failure.

One-step reconstruction of the right inferior hepatic veins using auto-venous grafts in living-donor liver transplantation

PURPOSES

Reconstruction of the right inferior hepatic vein (RIHV) presents a major technical challenge in living donor liver transplantation (LDLT) using right lobe grafts.

METHODS

We studied 47 right lobe LDLT grafts with RIHV revascularization, comparing one-step reconstruction, performed post-May 2007 (n = 16), with direct anastomosis, performed pre-May 2007 (n = 31).

RESULTS

In the one-step reconstruction technique, the internal jugular vein (n = 6), explanted portal vein (n = 5), inferior vena cava (n = 3), and shunt vessels (n = 2) were used as venous patch grafts for unifying the right hepatic vein, RIHVs, and middle hepatic vein tributaries. By 6 months after LDLT, there was no case of occlusion of the reconstructed RIHVs in the one-step reconstruction group, but a cumulative occlusion rate of 18.2 % in the direct anastomosis group. One-step reconstruction required a longer cold ischemic time (182 ± 40 vs. 115 ± 63, p < 0.001) and these patients had higher alanine transaminase values (142 ± 79 vs. 96 ± 46 IU/L, p = 0.024) on postoperative day POD 7. However, the 6-month short-term graft survival rates were 100 % with one-step reconstruction and 83.9 % with direct anastomosis, respectively.

CONCLUSION

One-step reconstruction of the RIHVs using auto-venous grafts is an easy and feasible technique promoting successful right lobe LDLT.

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.

A 3D porous media liver lobule model: the importance of vascular septa and anisotropic permeability for homogeneous perfusion

The hepatic blood circulation is complex, particularly at the microcirculatory level. Previously, 2D liver lobule models using porous media and a 3D model using real sinusoidal geometries have been developed. We extended these models to investigate the role of vascular septa (VS) and anisotropic permeability. The lobule was modelled as a hexagonal prism (with or without VS) and the tissue was treated as a porous medium (isotropic or anisotropic permeability). Models were solved using computational fluid dynamics. VS inclusion resulted in more spatially homogeneous perfusion. Anisotropic permeability resulted in a larger axial velocity component than isotropic permeability. A parameter study revealed that results are most sensitive to the lobule size and radial pressure drop. Our model provides insight into hepatic microhaemodynamics, and suggests that inclusion of VS in the model leads to perfusion patterns that are likely to reflect physiological reality. The model has potential for applications to unphysiological and pathological conditions.

Predictive factors of early graft loss in living donor liver transplantation

CONTEXT

Living donor liver transplantation has become an alternative to reduce the lack of organ donation.

OBJECTIVE

To identify factors predictive of early graft loss in the first 3 months after living donor liver transplantation.

METHODS

Seventy-eight adults submitted to living donor liver transplantation were divided into group I with 62 (79.5%) patients with graft survival longer than 3 months, and group II with 16 (20.5%) patients who died and/or showed graft failure within 3 months after liver transplantation. The variables analyzed were gender, age, etiology of liver disease, Child-Pugh classification, model of end-stage liver disease (MELD score), pretransplantation serum sodium level, and graft weight-to-recipient body weight (GRBW) ratio. The GRBW ratio was categorized into < 0.8 and MELD score into >18. The chi-square test, Student t-test and uni- and multivariate analysis were used for the evaluation of risk factors for early graft loss.

RESULTS

MELD score <18 (P<0.001) and serum sodium level > 135 mEq/L (P = 0.03) were higher in group II than in group I. In the multivariate analysis MELD scores > 18 (P<0.001) and GRBW ratios < 0.8 (P<0.04) were significant.

CONCLUSIONS

MELD scores >18 and GRBW < 0.8 ratios are associated with higher probability of graft failure after living donor liver transplantation.

[Small-for-size: experimental findings for liver surgery]

The characteristics of the hepatic macrocirculation, i.e., the parallel portal-venous and arterial blood supply, is of utmost relevance for liver surgery. With extended hepatectomy or transplantation of a reduced-size liver the remaining or transplanted liver tissue is overperfused because the liver fails to regulate the portal-venous inflow. This portal hyperperfusion is responsible for the initiation of liver cell proliferation but represents at the same time one of the substantial events in the pathogenesis of the small-for-size syndrome. Portal-venous hyperperfusion, the so-called hepatic arterial buffer response, which describes the semi-reciprocal relationship between the portal-venous and hepatic arterial blood flows, leads to an arterial hypoperfusion of the small-for-size liver. In this article experimental and clinical data are discussed which underline the high but so far overseen relevance of this arterial underperfusion in the development of a small-for-size syndrome.

Amphiregulin stimulates liver regeneration after small-for-size mouse liver transplantation

This study investigated whether amphiregulin (AR), a ligand of the epidermal growth factor receptor (EGFR), improves liver regeneration after small-for-size liver transplantation. Livers of male C57BL/6 mice were reduced to ~50% and ~30% of original sizes and transplanted. After transplantation, AR and AR mRNA increased in 50% but not in 30% grafts. 5-Bromodeoxyuridine (BrdU) labeling, proliferating cell nuclear antigen (PCNA) expression and mitotic index increased substantially in 50% but not 30% grafts. Hyperbilirubinemia and hypoalbuminemia occurred and survival decreased after transplantation of 30% but not 50% grafts. AR neutralizing antibody blunted regeneration in 50% grafts whereas AR injection (5 μg/mouse, iv) stimulated liver regeneration, improved liver function and increased survival after transplantation of 30% grafts. Phosphorylation of EGFR and its downstream signaling molecules Akt, mTOR, p70S6K, ERK and JNK increased markedly in 50% but not 30% grafts. AR stimulated EGFR phosphorylation and its downstream signaling pathways. EGFR inhibitor PD153035 suppressed regeneration of 50% grafts and largely abrogated stimulation of regeneration of 30% grafts by AR. AR also increased cyclin D1 and cyclin E expression in 30% grafts. Together, liver regeneration is suppressed in small-for-size grafts, as least in part, due to decreased AR formation. AR supplementation could be a promising therapy to stimulate regeneration of partial liver grafts.

Effect of portal haemodynamics on liver graft and intestinal mucosa after small-for-size liver transplantation in swine

BACKGROUND

After small-for-size graft (SFSG) transplantation, elevated portal venous pressure (PVP) may lead to postoperative liver damage. Herein we evaluated the impact of portocaval shunt (PCS) to control PVP on liver grafts and intestine following SFSG transplantation.

METHODS

Nineteen SFSG transplantations were performed with 30% of native liver in swine. Swine were divided into 3 groups: a high-flow shunt group (HS: n = 7), in which portal venous flow (PVF) was reduced with a 10-mm diameter PCS; a low-flow shunt group (LS: n = 6), in which PVF was reduced with a 5-mm diameter PCS, and a no-shunt group (NS: n = 6), in which no PCS was placed.

RESULTS

Seven-day survivals were 83.3% in NS, 100% in LS and 0% in HS (p = 0.0088). PVP was significantly higher in the NS group (p = 0.0001; mean ± SEM NS/LS/HS: 20.5 ± 0.7/14.0 ± 1.2/11.6 ± 0.5 mm Hg). The LS group exhibited the highest compliance (PVF/PVP; NS/LS/HS 42.7 ± 10.9/44.6 ± 4.9/37.7 ± 8.3 ml/min/mm Hg; p = 0.009), the lowest aspartate aminotransferase (NS/LS/HS 562 ± 18/370 ± 55/720 ± 130 IU/l; p = 0.0493), and suppressed deleterious alternations of the hepatic parenchyma and intestinal mucosa.

CONCLUSIONS

Portal hypertension after SFSG transplantation impaired liver and intestinal mucosa; however, inadequate portal flow impaired not only the liver, but also survival.

Injury of the hepatic barrier and intestinal barrier in patients with small-for-size graft syndrome after partial liver transplantation: mechanisms and protective measures

The intestinal barrier can resist the invasion of pathogens and prevent harmful substances from going into blood circulation to maintain the stability of internal environment, while the hepatic barrier is a vital structure that can protect liver function and prevent endotoxin and virus from entering the liver to damage hepatocytes. Both the two barrier structures are most vulnerable to damage after partial liver transplantation due to the occurrence of postoperative 'small-for-size graft syndrome'. The pathogenesis of 'small-for-size graft syndrome' is associated with postoperative portal hypertension and hyperperfusion. How to effectively control the occurrence of 'small-for-size graft syndrome' and to protect the intestinal barrier and hepatic barrier postoperatively are key to the maintenance of intestinal and hepatic functions. The primary aim of this paper is to review the mechanisms underlying the development of injury of the hepatic barrier and intestinal barrier in patients with small-for-size graft syndrome after partial liver transplantation and to propose the corresponding protective measures.

Body surface area index predicts outcome in orthotopic liver transplantation

BACKGROUND/PURPOSE

In living donor liver transplantation (LDLT), matching of liver volume between donor and recipient is critical to the success of the procedure; mismatch can result in 'small- or large-for-size syndrome'. In orthotopic liver transplantation (OLT), matching criteria are less stringent and non-uniform. We sought to determine whether a new parameter, the ratio of donor to recipient body surface area (BSAi), is predictive of size mismatch and/or post-transplant morbidity or mortality.

METHODS

We reviewed data on 1228 OLT recipients and stratified this data according to three categories: small-for-size (BSAi <0.6), control (BSAi = 0.6-1.4), and large-for-size (BSAi >1.4) donors.

RESULTS

We found that: (1) matching of grafts at the upper and lower extremes of BSAi had significantly reduced graft survival; (2) matches with lower BSAi sustained a less severe form of intraoperative post-reperfusion syndrome, and the incidence of hepatic artery thrombosis was high postoperatively in these grafts; (3) BSAi and donor age correlated well with the severity of intraoperative post-reperfusion hypotension; and (4) small-for-size (BSAi <0.6) and large-for-size (BSAi >1.4) grafts, as well as preoperative total bilirubin, were significant risk factors for decreased graft survival.

CONCLUSION

We conclude that the BSAi can predict clinically significant size mismatch and adverse outcomes in cadaveric whole OLT.

Deconvolution assessment of splenic and splanchnic contributions to portal venous blood flow in liver cirrhosis

PURPOSE

To devise a noninvasive imaging method for resolving the relative contribution of splenic and splanchnic blood flow to portal venous flow and derive quantitative estimates for parameters pertaining to splenic and portal hemodynamics.

METHODS

Tracer concentration-time curves of the aorta, portal vein, and spleen can be extracted from dynamic contrast-enhanced (DCE) CT or MR images. A combination of two tracer analysis approaches, namely arterial-venous sampling and residual tracer deconvolution, is proposed to model these concentration-time curves and derive hemodynamic parameters pertaining to splenic and portal circulation. Clinical feasibility of the proposed method was explored using DCE CT datasets of eight cirrhotic patients. Monte Carlo simulations were performed to evaluate the confidence of the parameter estimates.

RESULTS

Portal blood flow was estimated to be 763.8 +/- 438.1 ml/min in cirrhotic patients and the splenic contribution was found to be elevated (0.75 +/- 0.22). Estimates of splenic blood flow (582 +/- 420 ml/min) and transit time (15.3 +/- 10.1 s) in cirrhotic patients were consistent with reported values obtained using duplex Doppler ultrasound and dynamic scintigraphy, respectively.

CONCLUSIONS

This study shows the feasibility of noninvasive assessment of splenic and portal hemodynamic parameters by DCE imaging using a combination of tracer kinetics modeling techniques.