Portal vein complications in pediatric living donor liver transplantation using left-side grafts

Thrombotic complications post liver transplantation: Etiology and management

Liver transplantation (LT) is the life saving therapeutic option for patients with acute and chronic end stage liver disease. This is a routine procedure with excellent outcomes in terms of patient survival and quality of life post LT. Orthotopic LT (OLT) patients require a critical care as they are prone to variety of post-operative vascular, cardiovascular, biliary, pulmonary and abdominal complications. Thrombotic complications (both arterial and venous) are not uncommon post liver transplant surgery. Such vascular problems lead to increased morbidity and mortality in both donor and graft recipient. Although thromboprophylaxis is recommended in general surgery patients, no such standards exist for liver transplant patients. Drastic advancements of surgical and anesthetic procedures have improvised survival rates of patients post OLT. Despite these, haemostatic imbalance leading to thrombotic events post OLT cause significant graft loss and morbidity and even lead to patient’s death. Thus it is extremely important to understand pathophysiology of thrombosis in LT patients and shorten the timing of its diagnosis to avoid morbidity and mortality in both donor and graft recipient. Present review summarizes the current knowledge of vascular complications associated with LT to highlight their impact on short and long-term morbidity and mortality post LT. Also, present report discusses the lacunae existing in the literature regarding the risk factors leading to arterial and venous thrombosis in LT patients.

Clinical Implications of Serum Mac-2 Binding Protein in Patients After Living Donor Liver Transplantation for Biliary Atresia

BACKGROUND

Patients who undergo pediatric living donor liver transplantation (LDLT) sometimes develop graft fibrosis. Recently, Mac-2 binding protein glycosylation-modified isomer (M2BPGi) was developed as a new marker of hepatic fibrosis progression. We performed this study to examine the relationship between serum M2BPGi levels and liver histologic findings in patients after LDLT for biliary atresia.

METHODS

Patients aged <19 years who underwent LDLT for biliary atresia at our institution and followed up for at least 1 year after LDLT were eligible. There were 56 patients in this study. Pathologic findings of the last available biopsy were assessed. Portal vein (PV) stenosis was confirmed with angiography. M2BPGi levels were compared with pathologic fibrosis scores and PV stenosis findings.

RESULTS

The mean age at transplant was 4.3 years. The mean observation period was 8.6 years. In terms of the degree of liver fibrosis, F0 was observed in 7 patients, F1 in 36, and F2 in 13. The median serum M2BPGi value was 0.8 cut-off index (COI) overall and 0.60 COI for F0, 0.74 COI for F1, and 1.07 COI for F2. The mean M2BPGi value in F2 was higher than that in F0 (P = .016) and F1 (P = .012). Mean serum M2BPGi values were 1.57 COI (0.29 COI) in patients with PV complications (n = 5) and 0.72 COI in patients without PV complications (n = 51) (P = .0001).

CONCLUSION

M2BPGi is a novel marker for liver fibrosis in patients after pediatric LDLT. It is especially useful for follow-up of pediatric patients after LDLT to support liver biopsy interpretation.

Portal vein pressure and flow modulation in pediatric liver transplantation

Liver transplantation (LT) has been indicated for smaller and more clinically severe patients in recent years. Small biliary atresia (BA) patients often show portal hypoplasia and sclerotic portal vein (PV), which may make PV reconstruction more difficult during the operation. Among PV complications, intraoperative PV thrombosis can be considered a disaster, and it is important to prevent this catastrophic event by the precise assessment of the PV structure and PVF using radiological imaging before and during LT. However, there are no objective parameters to indicate whether sufficient PVF can be obtained. PV pressure (PVP) and PV flow (PVF) have mainly been studied in adult living donor LT, for the purpose of preventing small-for-size syndrome, and PVP has been considered an objective parameter of graft inflow modulation (GIM). In the setting of pediatric LT, GIM is mainly performed to prevent hypoperfusion, and it must be performed before graft implantation. GIM to maximize the PVF of pediatric patients with potentially low PVF in LT consists of the interruption of collateral vessels, the assessment of the usability of the native PV, and technical modifications in PV reconstruction. Reliable objective parameters that represent sufficient PVF before graft implantation are desired. Our recent study proposed that a PVP of ≥25 mmHg before graft implantation can be considered an objective parameter to obtain sufficient PVF (cutoff value: 50 mL/min/100 g of graft weight). Further investigation is needed to determine the best strategy for successful PV reconstruction in pediatric LT.

The impact of portal vein reconstruction on portal vein complications after pediatric living-donor liver transplantation with left lobe graft

BACKGROUND

This study aimed to determine whether the different methods of portal vein reconstruction have an impact on the occurrence of portal vein complications after pediatric living-donor liver transplantation with left lobe graft.

METHODS

A total of 567 recipients were eligible for enrollment in this study and were divided into the following 2 groups according to the type of portal vein reconstruction: group 1 underwent anastomosis of the left and right bifurcations of the recipient portal vein to the donor portal vein (type 1), whereas group 2 underwent anastomosis of the bevel formed by the main trunk and right branch of the recipient portal vein to the donor portal vein (type 2). Postoperative portal vein complications and recipient and graft survival rates were compared between the 2 groups before and after propensity score matching.

RESULTS

Portal vein complications occurred in 53 (9.3%) patients, including 46 recipients with portal vein stenosis and 7 with portal vein thrombosis. After propensity score matching, the incidence of portal vein stenosis in group 2 was lower than that in group 1 (P = .035). The first diagnosis time of portal vein stenosis in group 2 was later than that in group 1 (P = .033), and the incidence of early portal vein stenosis was lower than that in group 1 (P = .009). There were no statistically significant differences in the incidence of portal vein thrombosis and recipient and graft survival rates between the 2 groups.

CONCLUSIONS

Type 2 portal vein reconstruction appears to be a viable technique in pediatric living-donor liver transplantation with left lobe graft that can effectively reduce the incidence of portal vein stenosis.

Treatments and outcomes of intra-operative portal vein thrombosis in living-donor liver transplantation due to biliary atresia

BACKGROUND

Pediatric living-donor liver transplantation (LDLT) has become one of the most effective therapies for pediatric end-stage liver diseases. We aim to investigate the risk factors for intra-operative portal vein thrombosis (PVT) and the short- and long-term outcomes in children post LDLT.

METHODS

This was a retrospective analysis from 584 cases of biliary atresia (BA) patients who had undergone LDLT from January 2014 to December 2019 at our hospital. Patients were divided into PVT and non-PVT groups according to the occurrence of PVT during LDLT.

RESULTS

The median age of recipients at transplantation was 7.22 (quartiles, 6.03, 9.50) months, the incidence of intra-operative PVT was 5.31% (31/584). The independent risk factors for intra-operative PVT were the diameter of the recipient's PV not greater than 4 mm and a higher ratio of graft-to-recipient PV diameter. The cumulative survival rates of grafts and recipients were 93.5% and 93.5% in the PVT group, and 94.9% and 95.3% in the non-PVT group, respectively, without significant difference. The recovery of graft function was similar in recipients with or without interposed graft vessel (IGV). However, the incidence of PV stenosis was higher in recipients with IGV after LDLT.

CONCLUSION

Intra-operative PVT is a common complication in pediatric LDLT, but an excellent prognosis can be achieved by appropriate and individualized surgical treatment. We noted that intra-operative PVT did not affect the survival rates of grafts and recipients, but there was a higher incidence of PV complications after LDLT.

LEVEL OF EVIDENCE

Ⅲ.

The Role of Imaging in Portal Vein Thrombosis: From the Diagnosis to the Interventional Radiological Management

PURPOSE

To illustrate diagnostic and interventional imaging for the characterization and treatment of portal vein thrombosis (PVT).

INTRODUCTION

The broad spectrum of congenital and acquired PVT manifestations is illustrated, with a focus on the pediatric population; diagnostic and interventional imaging techniques are described.

DESCRIPTION

PVT frequently presents as an incidental finding at imaging in the screening for liver diseases or for other unrelated reasons. PVT can be classified based on: extension (intrahepatic, extrahepatic, involving the spleno-mesenteric tract, etc.); degree (partial or complete); onset (acute or chronic); and with or without cavernomatous transformation. This comprehensive review relies on the experience gained from a large series of congenital and acquired PVT in a referral center for pediatric and adult liver transplantation. Diagnostic and interventional imaging techniques are described, including: color-Doppler and contrast-enhanced Ultrasound; CT and MR angiography; retrograde portography; percutaneous transhepatic, transplenic, and transmesenteric portography; transjugular intrahepatic portosystemic shunt creation. Pre- and post-operative imaging assessment of the surgical meso-rex bypass is discussed. The description is enriched with an original series of pictorial imaging findings.

CONCLUSION

PVT is a clinical condition associated with significant morbidity and mortality. Diagnostic and interventional imaging plays a crucial role in both conservative and operative management.

Predictors of portal vein complications after pediatric liver transplantation: A German center experience

BACKGROUND

Portal vein complications (PVCs) after pediatric liver transplantation (LT) are sometimes asymptomatic, especially in the early phase, and can threaten both the graft and patient's survival. Therefore, the purpose of this study is to analyze the risk factors for portal vein thrombosis (PVT) and portal vein stenosis (PVS) after pediatric LT.

METHODS

All pediatric patients (n = 115) who underwent primary LT at Regensburg University Hospital between January 2010 and April 2017 were included in this study. The pre-, intra-, and postoperative parameters of all patients were retrospectively reviewed and risk factors for both PVT and PVS were analyzed.

RESULTS

Of the 115 patients, living donor LT was performed on 57 (49.5%) patients, and biliary atresia was the primary diagnosis in 65 patients (56%). After pediatric LT, 9% of patients developed PVT, and 16.5% developed PVS. Patient weight ≤7 kg [odds ratio (OR) 9.35, 95% confidence interval (CI) 1.03-84.9, p = .04] and GRWR >3% (OR 15.4, 95% CI 1.98-129.5, p = .01) were the independent risk factors for the development of PVT and PVS, respectively upon multivariate analysis. The overall patient survival rates at 1, 3, and 5 years were 91%, 90%, and 89%, respectively, and there was no difference in patient survival among those with and without PVCs.

CONCLUSIONS

Pediatric patients with body weight <7 kg and/or receiving a graft with GRWR >3% may develop PVCs and so require certain surgical modifications, close follow-up, and prophylactic anticoagulant therapy following transplant.

Clinical implications of serum autotoxin in regular follow up after pediatric living donor liver transplantation for biliary atresia

BACKGROUND

Pediatric patients sometimes develop graft fibrosis after living donor liver transplant (LDLT). Autotaxin is a recently developed serum marker for hepatic fibrosis. We studied the relationship between serum autotaxin levels and histological findings in patients after LDLT for biliary atresia (BA).

METHODS

Information on patients aged <19 years who received LDLT for BA and were followed for at least 1 year after LDLT was gathered. Autotaxin levels were compared with pathological fibrosis scores.

RESULTS

The study included 52 patients, of whom 4 patients had no fibrosis (F0), 36 patients had F1 fibrosis, and 12 patients had F2. The median serum autotaxin level was 0.89 mg/L. In patients with portal vein (PV) complications such as stenosis or thrombosis (n = 7), the mean autotoxin level was 1.25 mg/L compared with 0.95 mg/L in patients without PV complications (p = 0.004). Among patients without PV complications, the mean autotaxin level was 0.90, 0.88, and 1.18 mg/L in F0, F1, and F2 fibrosis, respectively. The mean autotaxin was higher in F2 fibrosis than in F0 or F1 fibrosis (p<0.05). Autotoxin had a high area under the curve (0.86) with the cut-off level of 0.897 mg/L.

CONCLUSION

Serum autotaxin is a novel marker for liver fibrosis in patients after pediatric LDLT for BA.

TYPE OF STUDY

Study of Diagnostic Test.

LEVEL OF EVIDENCE

Level II.

Vascular Complications in Pediatric Liver Transplants and Their Management

OBJECTIVES

The blood supply of the liver occurs through the hepatic artery and portal vein. Outflow of blood circulation in the liver is via the hepatic veins. Any disruption in this blood circulation results in deterioration of liver functions. In this study, we evaluated early vascular complications in pediatric liver transplant recipients seen at our center.

MATERIALS AND METHODS

From November 1988 to December 2021, our team has performed 701 liver transplant procedures, which have included 334 pediatric liver transplants. Among these pediatric liver transplant recipients (mean age of 7.34 y), 176 were male patients. Nineteen patients (5.7%) were recipients of deceased donors. Reason for liver failure was mainly biliary atresia (n = 169). Mean weight of recipients was 23.3 kg. Most graft types were left lateral grafts (n = 204).

RESULTS

Three patients had hepatic vein complications. All 3 patients were successfully treated with interventional radiological methods by placing a stent in the anastomosis region. Portal vein complications occurred in 3 patients. One patient had hemostasis performed surgically. The second patient had surgically revision of the anastomosis because of thrombus formation. Because of stenosis of more than 50% in the portal vein anastomosis, the third patient required stent placement in the anastomosis region. Hepatic artery complications occurred in 54 patients: 31 patients had hepatic artery thrombosis, 13 patients had hepatic artery stenosis, 7 patients had bleeding from hepatic artery anastomosis, 2 patients had hepatic artery dissection, and 1 patient had pseudoaneurysm in the hepatic artery. Forty-three of these patients were successfully treated with interventional radiological methods and 11 required surgical treatment.

CONCLUSIONS

Vascular complications after liver transplant can cause deterioration in hepatic functions and acute liver failure. Vascular complications can be successfully treated in experienced organ transplant centers.

Portal vein reconstruction with cryopreserved vascular grafts: A two-edged sword

BACKGROUND

Portal vein anastomotic complications related to size discrepancy are important causes of morbidity and mortality in pediatric liver transplantation. Interposed vascular grafts in portal vein anastomosis can solve this problem. The aim of this study is to evaluate the results of pediatric liver transplantations performed using cryopreserved interposed vascular grafts between graft portal vein and superior mesenteric vein (SMV)-splenic vein (SpV) confluence.

METHODS

Twenty-nine pediatric patients received liver transplantation using cryopreserved venous grafts in our Liver Transplant Institute between 2013 and 2020 were included in this study. Demographic, clinical, and operative characteristics and postoperative follow-up were analyzed.

RESULTS

Sixteen patients (55.2%) had portal hypoplasia and five patients (17.2%) had portal vein thrombosis. In total, six patients (20.6%) suffered portal vein thrombosis in the early postoperative period. Three patients (10.3%) experienced portal vein thrombosis in the late postoperative period. Late portal vein thrombosis rate was significantly higher in patients with early portal vein thrombosis (3/6 patients [50%] versus 0/23 patients [0%]; p = .034). Lack of portal flow was significantly higher in patients with both early (50% versus 0%; p = .002) and late portal vein thrombosis (66.7% versus 6.7%; p = .03).

CONCLUSION

Preoperative portal vein thrombosis and insufficient flow are important factors affecting success of liver transplant in children. The use of interposed vein grafts in problematic portal anastomoses can overcome portal flow problems.

Technical Aspects and Considerations of Meso-Rex Bypass Following Liver Transplantation With Left Lateral Segment Grafts: Case Report and Review of the Literature

In pediatric patients with extrahepatic portal vein obstruction and complications of portal hypertension, but with normal liver function, a meso-Rex bypass (MRB) connecting the superior mesenteric vein to the intrahepatic left portal is the favored surgical management. Pediatric patients with a history of a partial liver transplant (LT), especially living donors, are at greater risk for portal vein complications. Hence, an adequate knowledge of this technique and its additional challenges in the post-LT patient setting is crucial. We provide an overview of the available literature on technical aspects for an MRB post-LT. Preoperative considerations are highlighted, along with intraoperative considerations and postoperative management. Special attention is given to the even-more-demanding aspect of performing an MRB post-liver transplantation with a left lateral segment. Surgical alternatives are also discussed. In addition, we report here a unique case in which this surgical technique was performed on a complex pediatric patient with a history of a living-donor LT with a left lateral segment graft over a decade ago.

Impact of Graft Size Matching on the Early Post-Transplant Complications and Patients Survival in Children after Living Donor Liver Transplantations

We aimed to assess the impact of the graft-recipient weight ratio (GRWR) on early post-transplant complications and patient survival rates in children after living donor liver transplantation (LDLT). We retrospectively analyzed 321 patients who underwent LDLT from 2004 to 2019. The recipients were categorized into four groups: 37 patients had a GRWR ≤ 1.5% (Group A), 196 patients had a GRWR > 1.5% and ≤3.5% (Group B), 73 patients had a GRWR > 3.5% and <5% (Group C) and 15 patients had a GRWR ≥ 5% (Group D). Incidence of early surgical complications including vascular complications, biliary complications, postoperative bleedings, gastrointestinal perforations and graft loss were comparable among groups with a different GRWR. Delayed abdominal wound closure was more common in patients with a GRWR > 3.5%. Recipients with a GRWR < 5% had a significantly better prognosis concerning patients and graft survival. Using grafts with a GRWR < 5% allows us to expand the donor pool and decrease the risk of mortality while on the waiting list, when patients at the time of transplantation have less advanced liver disease. LDLT with a GRWR ≥ 5% is related to a higher risk of poor outcome, and thus should be an option for treating selected patients when the risk of a delayed transplantation is high and access to deceased donors is limited.

The Application of Interventional Radiology in Living-Donor Liver Transplantation

Owing to improvements in surgical techniques and medical care, living-donor liver transplantation has become an established treatment modality in patients with end-stage liver disease. However, various vascular or non-vascular complications may occur during or after transplantation. Herein, we review how interventional radiologic techniques can be used to treat these complications.

Technical Choices in Pediatric Living Donor Liver Transplantation: The Path to Reduce Vascular Complications and Improve Survival

Pediatric living donor liver transplantation (PLDLT) is a successful therapeutic option for children with chronic and acute liver disease. After early transplant results, many technical advancements were introduced in the field to reduce the rate of complications and improve survival. The aim of this study is to present the outcomes of 975 primary PLDLTs in 3 periods: initial practice (period 1, 29 patients, January 1995 to December 1999), second period (period 2, 331 patients, January 2000 to December 2009), and third period (period 3 [P3], 615 patients, January 2010 to September 2019). Among the technical refinements introduced in P3 are the use of hyperreduced left lateral segment grafts, abdominal wall prosthetic mesh closure, double hepatic artery anastomosis, and increased use of vascular grafts for portal vein reconstruction. The outcomes included significant reductions of hepatic artery thrombosis (HAT), early portal vein thrombosis (EPVT), and retransplantation, with better patient and graft survival in P3. Additional analyses showed that the factors independently associated with worse 90-day patient survival were HAT, EPVT, and increasing Pediatric End-Stage Liver Disease score. In conclusion, the introduction of technical refinements in P3, in addition to improvements in patient care, determined a reduction in EPVT, HAT, and retransplantation. Consequently, patient and graft survival rates increased in all time points studied.

Outcome of Pediatric Liver Transplants in Patients With Less Than 10 kg of Body Weight Is Not Worse

OBJECTIVES

Liver transplant in pediatric patients with body weight < 10 kg poses a challenge to the entire liver transplant team. Many reports have considered 10 kg to be a cutoff pointfor body weightforfavorable posttransplant outcomes. With evolving surgical techniques and postoperative management, there is potential to improve outcomes in this subset of recipients. We compared the outcomes in pediatric patients with body weight < 10 kg with those > 10 kg; also, we studied the factors of influence.

MATERIALS AND METHODS

We performed a retrospective analysis to evaluate the outcomes of liver transplants in pediatric patients with < 10 kg body weight. The cohort consisted of 90 children subdivided into the following 2 subgroups: group A (n = 35) with > 10 kg body weight at liver transplant and group B (n = 55) with < 10 kg body weight at liver transplant. We compared the following pretransplant characteristics between the groups: graft weight, graft-to-recipient weightratio, cold ischemia time, warm ischemia times, and liver transplant outcomes.

RESULTS

Pediatric End-stage Liver Disease score was significantly higher in group B (score of 24) versus group A (score of 18). Group B had significantly higher graft-to-recipient weight ratio (2.8 in group B vs 1.7 in group A). Graft function showed no significant difference between the 2 groups. Portal vein thrombosis was seen only in group B, whereas biliary leaks were observed among 5 patients in group B and 1 patientin group A. Patient survivalrate was higherin group B (86%) than in group A (77%).

CONCLUSIONS

Pediatric patients weighing < 10 kg have similarif not better survivalrates after liver transplant compared with patients > 10 kg. Advancements in surgical techniques and a careful monitoring for complications and timely intervention are important to facilitate these outcomes.

Phase I/II Trial of Liver-derived Mesenchymal Stem Cells in Pediatric Liver-based Metabolic Disorders: A Prospective, Open Label, Multicenter, Partially Randomized, Safety Study of One Cycle of Heterologous Human Adult Liver-derived Progenitor Cells (HepaStem) in Urea Cycle Disorders and Crigler-Najjar Syndrome Patients

BACKGROUND

Regenerative medicine using stem cell technology is an emerging field that is currently tested for inborn and acquired liver diseases.

OBJECTIVE

This phase I/II prospective, open label, multicenter, randomized trial aimed primarily at evaluating the safety of Heterologous Human Adult Liver-derived Progenitor Cells (HepaStem) in pediatric patients with urea cycle disorders (UCDs) or Crigler-Najjar (CN) syndrome 6 months posttransplantation. The secondary objective included the assessment of safety up to 12 months postinfusion and of preliminary efficacy.

METHODS

Fourteen patients with UCDs and 6 with CN syndrome were divided into 3 cohorts by body weight and intraportally infused with 3 doses of HepaStem. Clinical status, portal vein hemodynamics, morphology of the liver, de novo detection of circulating anti-human leukocyte antigen antibodies, and clinically significant adverse events (AEs) and serious adverse events to infusion were evaluated by using an intent-to-treat analysis.

RESULTS

The overall safety of HepaStem was confirmed. For the entire study period, patient-month incidence rate was 1.76 for the AEs and 0.21 for the serious adverse events, of which 38% occurred within 1 month postinfusion. There was a trend of higher events in UCD as compared with CN patients. Segmental left portal vein thrombosis occurred in 1 patient and intraluminal local transient thrombus in a second patient. The other AEs were in line with expectations for catheter placement, cell infusion, concomitant medications, age, and underlying diseases.

CONCLUSIONS

This study led to European clinical trial authorization for a phase II study in a homogeneous patient cohort, with repeated infusions and intermediate doses.

Unusual venous collateral pathways allow for reperfusion of the intrahepatic portal venous system in children with portal vein thrombosis after split liver transplantation: Clinical relevance and management implications

PVT is the most frequent vascular complication after LT in small children, and a higher incidence has been observed in those transplanted for biliary atresia or with a LLSG. Thrombosis of the PV causes extrahepatic portal hypertension and is associated with splenomegaly and the development of venous neo-collaterals, including gastro-oesophageal varices and splenorenal shunts. It has also been incidentally suggested in the literature that patients who have had a Roux-en-Y loop for a biliary reconstruction may present with a cavernomatous transformation of the distal portion of the loop. In this study, 13 children with CEPH caused by thrombosis of the PV after LT were analysed. The study evidenced the development of two types of hepatopetal venous networks: (a) a large cavernoma along the Roux loop and around the biliary anastomosis, and (b) a network of neo-collaterals in the gastro-duodeno-pancreatic area that connected to the intrahepatic portal branches directly through the liver capsule. These hepatopetal venous networks between the venous system of the surrounding organs or the omentum and the intrahepatic portal branches can be identified by radiologists. The relevance for the transplanting physician and the transplant surgeon is discussed.

"Left at right" liver transplantation with heterotopic implantation of left liver graft in the right subphrenic space: Reappraisal and technical concerns for decision making

Conventional orthotopic implantation of left liver grafts is technically demanding and requires consideration of limited space and vascular complications. The study proposed a modified approach termed "left at right" liver transplantation (LAR-LT), wherein left liver grafts were rotated and implanted in right subphrenic spaces. The selection of recipients for this approach is based on the measurement of the right subphrenic space width and left liver graft length, in which a rotated left liver graft could be comfortably placed in the right subphrenic space. A total of 36 recipients who had undergone LAR-LT between July 2006 and December 2017 were retrospectively reviewed. None of recipients died of complications related to this approach immediately after operation. All grafts showed remarkable increment in liver volume and bi-directional regeneration to fit well within the right abdominal cavity. Meanwhile, the alignment of the biliary tree in LAR-LT is quite straight, making no difficulty in both anastomosis during operation and dealing with biliary stenosis afterward. As such, long-term outcome of LAR-LT is satisfactory. Keeping in mind certain technical concerns, a heterotopic LAR-LT might be safely applied as an alternative with an easier reconstruction procedure for select patients.

Novel technique for pediatric living donor liver transplantation in patients with portal vein obstruction: The "pullout technique"

PV hypoplasia may increase the risk of posttransplant complications, especially when it extends to near the SMV and SpV junction. We described our experience of 10 pediatric cases of PV hypoplasia/thrombus in which the pullout technique was required for PV reconstruction. There were five male and five female patients. The median age was 9 months, and the median weight was 8.1 kg. The indications for the pullout technique were PV hypoplasia in seven patients and PV thrombus in 3. The inflow sites of the enlarged LGV were as follows: the main PV trunk (n = 2), the SMV and SpV junction (n = 4), and the SpV (n = 4). The posterior face of the pancreas was tunneled along the PV, and the PV was returned to its original position with or without the use of an interposed vein graft. The pullout technique created a good operative field, which allowed for the complete removal of the hypoplastic PV or thrombectomy with the safe use of various interposed vein grafts.

Splenectomy as Flow Modulation Strategy and Risk Factors of De Novo Portal Vein Thrombosis in Adult-to-Adult Living Donor Liver Transplantation

Portal vein thrombosis (PVT) is a severe complication after liver transplantation that can result in increased morbidity and mortality. Few data are available regarding risk factors, classification, and treatment of PVT after living donor liver transplantation (LDLT). Between January 2004 and November 2014, 421 adult-to-adult LDLTs were performed at our institution, and they were included in the analysis. Perioperative characteristics and outcomes from patients with no-PVT (n = 393) were compared with those with de novo PVT (total portal vein thrombosis [t-PVT]; n = 28). Ten patients had early portal vein thrombosis (e-PVT) occurring within 1 month, and 18 patients had late portal vein thrombosis (l-PVT) appearing later than 1 month after LDLT. Analysis of perioperative variables determined that splenectomy was associated with t-PVT (hazard ratio [HR], 3.55; P = 0.01), e-PVT (HR, 4.96; P = 0.04), and l-PVT (HR, 3.84; P = 0.03). In contrast, donor age was only found as a risk factor for l-PVT (HR, 1.05; P = 0.01). Salvage rate for treatment in e-PVT and l-PVT was 100% and 50%, respectively, without having an early event of rethrombosis. Mortality within 30 days did not show a significant difference between groups (no-PVT, 2% versus e-PVT, 10%; P = 0.15). No significant differences were found regarding 1-year (89% versus 92%), 5-year (79% versus 82%), and 10-year (69% versus 79%) graft survival between the t-PVT and no-PVT groups, respectively (P = 0.24). The 1-year (89% versus 96%), 5-year (82% versus 86%), and 10-year (79% versus 83%) patient survival was similar for the patients in the no-PVT and t-PVT groups, respectively (P = 0.70). No cases of graft loss occurred as a direct consequence of PVT. In conclusion, the early diagnosis and management of PVT after LDLT can lead to acceptable early and longterm results without affecting patient and graft survival.

Improved portal vein venoplasty with an autogenous patch in pediatric living donor liver transplantation

A stenotic or hypoplastic portal vein (PV) represents a challenge for PV reconstruction in pediatric living donor liver transplantation (LDLT). Several PV venoplastic techniques have been developed. However, we still seek improved venoplastic techniques with better efficacy and compatibility. From June 2016 to July 2017, 271 LDLT procedures were performed at the Department of Liver Surgery, Renji Hospital. A total of 16 consecutive children with stenotic and sclerotic PVs underwent a novel technique-the autogenous PV patch plastic technique. Vessel patches were procured from the left branch (LB), or the bifurcation of the right branch and LB of the PV in the native liver. Then, the PVs were enlarged by suturing the patches along the longitudinal axis from the confluence of the PV and coronary vein (CV). In this series, 15/16 achieved good intraoperational PV flow, and 1 showed low PV flow but was treated with stent placement. Within a median follow-up of 11 months (1-18 months), 15 patients were alive and had normal graft function, whereas 1 child died from lung infection 1 month after transplantation. No PV complications were detected. In conclusion, the autogenous patch venoplasty technique using the PV-CV confluence is simple and safe. This novel venoplastic reconstruction technique could serve as a surgical option to achieve satisfactory outcomes, especially those with stenotic PV (<4.5 mm) and dilated CV (>3.0 mm). Liver Transplantation 2018 AASLD.

Intraoperative Doppler sonogram in pediatric liver transplants: a pictorial review of intraoperative and early postoperative complications

A spectrum of vascular complications can be seen in pediatric liver transplant patients, including occlusion and hemodynamically significant narrowing of the vessels that provide inflow to or outflow from the graft. Intraoperative Doppler ultrasound (US) has the potential benefit of identifying vascular complications in pediatric liver transplant patients prior to abdominal closure. Importantly, intraoperative Doppler US can be used as a problem-solving tool in situations such as position-dependent kinking of the portal or hepatic veins, or in suspected vasospasm of the hepatic artery. Furthermore, this technique can be used for real-time reassessment after surgical correction of vascular complications. This pictorial review of intraoperative Doppler US in pediatric liver transplant patients illustrates normal findings and common vascular complications, including examples after surgical correction, in the perioperative period.

Liver transplantation for biliary atresia: a systematic review

Biliary atresia (BA) is an idiopathic neonatal cholangiopathy characterized by progressive inflammatory obliteration of the intrahepatic or extrahepatic bile ducts. Although the Kasai operation has dramatically improved the outcomes in children with BA, most patients with BA eventually require liver transplantation (LT) even after undergoing a successful Kasai procedure. The Japanese LT Society (JLTS) was established in 1980 to characterize and follow trends in patient characteristics and the graft survival among all liver transplant patients in Japan. The 1-, 5-, 10-, 15- and 20-year survival rates for the patients and grafts undergoing living donor LT were 91.6, 91.5, 87.1, 85.4 and 84.2 and 90.5, 90.4, 84.6, 82.0 and 79.9%, respectively. LDLT was able to be performed even in patients weighing less than 5 kg with early liver failure following a Kasai operation using a reduced left lateral segments. As LT has been revealed to increase the donor pool and decrease the waiting list mortality with an excellent long-term graft survival, early referral to a transplant center should be considered when at least one complication of cirrhosis occurs during its natural history, especially in adolescents.

Liver and systemic hemodynamics in children with cirrhosis: Impact on the surgical management in pediatric living donor liver transplantation

Cirrhosis in adults is associated with modifications of systemic and liver hemodynamics, whereas little is known about the pediatric population. The aim of this work was to investigate whether alterations of hepatic and systemic hemodynamics were correlated with cirrhosis severity in children. The impact of hemodynamic findings on surgical management in pediatric living donor liver transplantation (LT) was evaluated. Liver and systemic hemodynamics were studied prospectively in 52 children (median age, 1 year; 33 with biliary atresia [BA]). The hemodynamics of native liver were studied preoperatively by Doppler ultrasound and intraoperatively using invasive flowmetry. Portosystemic gradient was invasively measured. Systemic hemodynamics were studied preoperatively by Doppler transthoracic echocardiography and intraoperatively by using transpulmonary thermodilution. Hemodynamic parameters were correlated with Pediatric End-Stage Liver Disease (PELD) score and the histological degree of fibrosis (collagen proportionate area [CPA]). Cirrhosis was associated with a 60% reduction of pretransplant total liver flow (n = 46; median, 36 mL/minute/100 g of liver) compared with noncirrhotic livers (n = 6; median, 86 mL/minute/100 g; P = 0.002). Total blood flow into the native liver was negatively correlated with PELD (P < 0.001) and liver CPA (P = 0.005). Median portosystemic gradient was 14.5 mm Hg in children with cirrhosis and positively correlated with PELD (P < 0.001). Portal vein (PV) hypoplasia was observed mainly in children with BA (P = 0.02). Systemic hemodynamics were not altered in our children with cirrhosis. Twenty-one children met the intraoperative criteria for PV reconstruction using a portoplasty technique during the LT procedure and had a smaller PV diameter at pretransplant Doppler ultrasound (median = 3.4 mm; P < 0.001). Cirrhosis in children appears also as a hemodynamic disease of the liver, correlated with cirrhosis severity. Surgical technique for PV reconstruction during LT was adapted accordingly. Liver Transplantation 23 1440-1450 2017 AASLD.

Outcomes of Percutaneous Portal Vein Intervention in a Single UK Paediatric Liver Transplantation Programme

Introduction

Percutaneous transluminal angioplasty (PTA), with or without stent placement, has become the treatment of choice for portal vein complications (PVC) following liver transplantation. We aimed to assess long-term outcomes of intervention in paediatric transplant recipients, in a single institution.

Materials and Methods

227 children received 255 transplants between November 2000 and September 2016. 30 patients developed PVC of whom 21 had percutaneous intervention. Retrospective clinical and procedural outcome data on these 21 patients were collected.

Results

21 patients, with median age 1.7 years (range 0.4–16.2), underwent 42 procedures with PTA with or without stenting. 36 procedures were for PV stenosis and 6 for PV thrombosis. Treatment was with primary PTA, with stenting reserved for suboptimal PTA result or restenosis within 3 months. 28 procedures were performed with PTA and 13 with stenting. Technical success (>50% reduction in mean pressure gradient, absolute pressure gradient ≤4 mmHg or venographic stenosis <30%) was achieved in 41 procedures. Failure to recanalise a thrombosed PV occurred in 1 procedure. There were no major procedural complications. Patients were followed-up with serial Doppler ultrasound surveillance. Kaplan–Meier estimated median primary patency was 9.9 months, with primary-assisted patency of 95% after median follow-up of 45.5 months (range 11.1–171.6).

Conclusion

With regular surveillance, excellent patency rates can be achieved following percutaneous intervention for PVC post-paediatric liver transplantation.

Living donor liver transplantation for post-Kasai biliary atresia: Analysis of pretransplant predictors of outcomes in infants

After decades of dramatic surgical innovations in pediatric living donor liver transplantation (LDLT), LDLT for biliary atresia (BA) still poses various challenges. This study reviewed our experience with LDLT for children with post-Kasai BA and evaluated outcomes and prognostic factors. From 2005 to 2016, 168 post-Kasai BA LDLT patients were enrolled and divided into 3 groups by age. Patient characteristics and perioperative data were compared. Predictors of morbidity and mortality following LDLT were analyzed in 93 infants. Outcome was relatively worse in infants than older children, with overall survival at 1 and 5 years of 94.5% and 93.2%, respectively, and graft survival at 1 and 5 years of 91.1% each. Incidence of vascular complications was not significantly higher in infants. High Pediatric End-Stage Liver Disease (PELD) score (odds ratio [OR], 3.72; 95% confidence interval [CI], 1.30-10.67; P = 0.02) and portal vein (PV) hypoplasia (OR, 3.23; 95% CI, 1.10-9.52; P = 0.03) were independent risk factors for morbidity. Low weight-for-age z score (hazard ratio, 5.76; 95% CI, 1.05-31.47; P = 0.03) was identified as a significant risk factor for mortality after LDLT, but not age or absolute body weight (BW). Infants with BW deficit had a significantly smaller PV diameter (P = 0.005), greater blood loss (P = 0.001), and higher incidence of postoperative bacteremia (P = 0.01). In conclusion, high PELD score and PV hypoplasia were independent risk factors for morbidity, and BW deficit was associated with poor survival in infants with post-Kasai BA after LDLT. However, LDLT in these infants at the earliest possible time after referral is a feasible option with excellent patient survival in an experienced center. Liver Transplantation 23 1199-1209 2017 AASLD.

The International Liver Transplantation Society Living Donor Liver Transplant Recipient Guideline

Living donor liver transplantation (LDLT) has been increasingly embraced around the world as an important strategy to address the shortage of deceased donor livers. The aim of this guideline, approved by the International Liver Transplantation Society (ILTS), is to provide a collection of expert opinions, consensus, and best practices surrounding LDLT. Recommendations were developed from an analysis of the National Library of Medicine living donor transplantation indexed literature using the Grading of Recommendations Assessment, Development and Evaluation methodology. Writing was guided by the ILTS Policy on the Development and Use of Practice Guidelines (www.ilts.org). Intended for use by physicians, these recommendations support specific approaches to the diagnostic, therapeutic, and preventive aspects of care of living donor liver transplant recipients.

Compared to cadaveric liver transplantation, live donor LT (LDLT) is challenged by ethical, medical and surgical considerations, many of which are still unresolved. The aim of this guideline is to provide a collection of expert opinions, consensus, and best practices surrounding LDLT.

Portal vein reconstruction using vein grafts in pediatric living donor liver transplantation: Current status

PV reconstruction is an important aspect of LDLT, with post-transplant outcomes depending on PV reconstruction methods. However, it is unclear whether the preferential selection of these techniques is dependent on preoperative recipient characteristics. This retrospective study assessed whether preoperative recipient factors differed in pediatric patients who did and did not receive VGs for PV reconstruction. Of 113 pediatric patients who underwent LDLT from January 2010 to July 2015, 31 (27%) underwent PV reconstruction with VGs and the other 82 (73%) without VGs. The presence of collateral vessels (P<.0001) and ascites (P=.02); PV size (P<.001), thrombosis (P=.01) and the direction of flow (P=.01), Child-Pugh class A vs B/C liver function (P=.01), Alb concentration (P=.02), primary diagnosis: BA vs non-BA (P=.03), and previous abdominal surgery (P<.005) differed significantly in patients who did and did not receive VGs for PV reconstruction. PV complications, patient survival, and graft survival did not differ significantly in patients with and without VGs at 1-year follow-up. VGs should be harvested for recipients with pretransplant hypoplastic PV, intense collaterals, hepatofugal flow, poor liver status, or previous abdominal surgery.

Correction of extrahepatic portal hypertension in pediatric patient after liver transplantation

Introduction. Liver transplantation is a multi-component and complex type of operative treatment. Patients undergoing such a treatment sometimes are getting various complications. One of these complications is a portal hypertension associated with portal vein stenosis.

Materials and methods. In 6 years after the left lateral section transplantation from living donor in a pediatric patient the signs of portal hypertension were observed. Stenosis of the portal vein was revealed. Due to this fact percutaneous transhepatic correction of portal vein stenosis was performed.

Results. As a result of the correction of portal blood flow in the patient a positive trend was noted. According to the laboratory and instrumental methods of examination the graft had a normal function, portal blood flow was adequate. In order to control the stent patency Doppler ultrasound and MSCT of the abdominal cavity with intravenous bolus contrasting were performed. Due to these examinations the stent function was good, the rate of blood flow in the portal vein due to Doppler data has reached 80 cm/sec, and a decrease of the spleen size was noted.

Conclusion. Diagnosis and timely detection of portal vein stenosis in patients after liver transplantation are very important for the preservation of graft function and for the prevention of portal hypertension. In order to do that, ultrasound Doppler fluorimetry examination needs to be performed to each patient after liver transplantation. In cases of violation of the blood flow in the portal vein CT angiography performance is needed. Percutaneous transhepatic stenting of portal vein is a minimally invasive and highly effective method of correction of portal hypertension. Antiplatelet therapy and platelet aggregation control are the prerequisites for successful stent function.

Interventional Treatment of Severe Portal Vein Thrombosis after Living-Donor Liver Transplantation

Portal vein thrombosis (PVT) is a rare complication of liver transplantation which can lead to graft failure and patient death. Treatment can be difficult, especially in cases of PVT from the intrahepatic portal vein to the proximal jejunal veins. A 55-year-old woman had undergone living-donor liver transplantation with splenectomy for end-stage liver cirrhosis due to hepatitis C with hepatocellular carcinoma. Ten months after transplantation, massive ascites and slight abdominal pain developed, and computed tomography revealed a PVT between the intrahepatic portal vein and the superior mesenteric vein. Repeated interventional radiology procedures were used in combination with thrombolysis, thrombectomy, and metallic stent replacement to obtain favorable portal flow to the graft. Five years after being treated, the patient is well, with favorable portal flow having been confirmed. In conclusion, repeated and assiduous interventional radiological treatment combined with thrombolytic therapy, thrombectomy, and metallic stent replacement could be important for severe PVT.

Alternatives for vascular reconstruction in pediatric living donor liver transplantation

Many publications discuss the various strategies for vascular reconstruction (VR) in pediatric LDLT. Having knowledge of alternative techniques is helpful in planning transplants. This article presents three case reports that illustrate some of the alternative techniques for HV, PV, and HA reconstruction in pediatric LDLT. It also reviews the available alternative strategies reported for VR in pediatric LDLT. In the first case, a 13-month-old girl presented a PRETEXT III HB with invasion of the retrohepatic vena cava. An LLS graft HV was anastomosed to a DD iliac vein graft and subsequently implanted in a "standard" fashion in the recipient. In the second case, a 44-month-old boy presented with multifocal HB and portomesenteric thrombosis and the portal inflow was done through a renoportal anastomosis. In the third case, a 22-month-old child with a failed Kasai procedure had extensive HA thrombosis. The HA reconstruction was performed with an interposition of the recipient's IMV graft. The use of alternative techniques for VR in pediatric LDLT is paramount to the success of such a complex procedure. Imaging studies can help transplant surgeons outline surgical strategies and define the best technique to be used in each case.

Hepatic arterial and portal venous complications after adult and pediatric living donor liver transplantation, risk factors, management and outcome (A retrospective cohort study)

OBJECTIVES

Hepatic arterial (HA) and portal venous (PV) complications of recipients after living donor liver transplantation(LDLT) result in patient loss. The aim of this study was to analyze these complications.

METHODS

We retrospectively analyzed HA and/or PV complications in 213 of 222 recipients underwent LDLT in our centre. The overall male/female and adult/pediatric ratios were 183/30 and 186/27 respectively.

RESULTS

The overall incidence of HA and/or PV complications was 19.7% (n = 42), while adult and pediatric complications were 18.3% (n = 39) and 1.4% (n = 3) respectively. However early (<1month) and late (>1month) complications were 9.4% (n = 20) and 10.3% (n = 22) respectively. Individually HA problems (HA stenosis, HA thrombosis, injury and arterial steal syndrome) 15% (n = 32), PV problems (PV thrombosis and PV stenosis) 2.8% (n = 6) and simultaneous HA and PV problems 1.9% (n = 4). 40/42 of complications were managed by angiography (n = 18), surgery (n = 10) or medically (Anticoagulant and/or thrombolytic) (n = 12) where successful treatment occurred in 18 patients. 13/42 (31%) of patients died as a direct result of these complications. Preoperative PVT was significant predictor of these complications in univariate analysis. The 6-month, 1-, 3-, 5- 7- and 10-year survival rates in patients were 65.3%, 61.5%, 55.9%, 55.4%, 54.5% and 54.5% respectively.

CONCLUSION

HA and/or PV complications specially early ones lead to significant poor outcome after LDLT, so proper dealing with the risk factors like pre LT PVT (I.e. More intensive anticoagulation therapy) and the effective management of these complications are mandatory for improving outcome.

Reno- and splenoportal anastomosis for a retransplant patient with situs inversus

PV thrombosis following pediatric LT is a serious complication that may lead to graft loss. LDLT poses limitations with regard to the availability of vein grafts for complex PV reconstructions. We herein report a unique reconstruction of the PV inflow in a one-yr-old boy with situs inversus undergoing re-LDLT. The inflow was derived from the SPV and the RRV. A common channel was created utilizing a donor IMV and the recipient explant LHV as vascular conduits. With the application of innovative surgical reconstructions, pre-existing portomesenteric thrombosis may be amenable to re-LDLT in the pediatric population.

Hepatic arterial and portal venous complications after adult and pediatric living donor liver transplantation, risk factors, management and outcome (A retrospective cohort study)

Objectives

Hepatic arterial (HA) and portal venous (PV) complications of recipients after living donor liver transplantation(LDLT) result in patient loss. The aim of this study was to analyze these complications.

Methods

We retrospectively analyzed HA and/or PV complications in 213 of 222 recipients underwent LDLT in our centre. The overall male/female and adult/pediatric ratios were 183/30 and 186/27 respectively.

Results

The overall incidence of HA and/or PV complications was 19.7% (n = 42), while adult and pediatric complications were 18.3% (n = 39) and 1.4% (n = 3) respectively. However early (<1month) and late (>1month) complications were 9.4% (n = 20) and 10.3% (n = 22) respectively. Individually HA problems (HA stenosis, HA thrombosis, injury and arterial steal syndrome) 15% (n = 32), PV problems (PV thrombosis and PV stenosis) 2.8% (n = 6) and simultaneous HA and PV problems 1.9% (n = 4). 40/42 of complications were managed by angiography (n = 18), surgery (n = 10) or medically (Anticoagulant and/or thrombolytic) (n = 12) where successful treatment occurred in 18 patients. 13/42 (31%) of patients died as a direct result of these complications. Preoperative PVT was significant predictor of these complications in univariate analysis. The 6-month, 1-, 3-, 5- 7- and 10-year survival rates in patients were 65.3%, 61.5%, 55.9%, 55.4%, 54.5% and 54.5% respectively.

Conclusion

HA and/or PV complications specially early ones lead to significant poor outcome after LDLT, so proper dealing with the risk factors like pre LT PVT (I.e. More intensive anticoagulation therapy) and the effective management of these complications are mandatory for improving outcome.

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Preoperative PVT was significant predictor of HA and/or PV complications.

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HA and/or PV complications especially early ones lead to significant poor outcome.

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Proper dealing with the risk factors like pre LT PVT improves outcome.

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The effective management of these complications is mandatory for improving outcome.

Results of pediatric living donor compared to deceased donor liver transplantation in the PELD/MELD era: Experience from two centers on two different continents

The LDLT option in the pediatric population allows recipients to be transplanted early. A total of 202 consecutive pediatric liver transplants from two different institutions--108 (LDLT) and 94 (DDLT)--were retrospectively compared. Overall, one- and three-yr patient and graft survival were similar between DDLT and LDLT. ACR was greater in recipients of DDLT at one and three yr (50.8% and 61.0%) compared to LDLT (30.8% and 32.2%) (p = 0.002). When the data were stratified according to PELD/MELD score, LDLT with a low score had better one- and three-yr graft survival (96.2% and 96.2%) compared to DDLT (88.2% and 85.2%) (p = 0.02), with comparable patient survival (p = 0.75). Patient and graft survival were similar between DDLT and LDLT in the high PELD/MELD group. Lower incidence of ACR in both low and high PELD/MELD groups was (29.6% and 34.3%) for LDLT compared to DDLT (50.3% and 53.3%, p = 0.002 and p = 0.028, respectively). Regardless of PELD/MELD score, status, age group, and recipient weight, LDLT provides excellent patient and graft survival with a lower incidence of rejection compared to DDLT.

A central approach to splenorenal shunt in pediatric living donor liver transplantation

The management of LSRS is a crucial problem to ensure a sufficient PV flow during pediatric LT. Although several techniques have been indicated to solve this problem, a more appropriate approach to LSRS is still needed in pediatric LT. We herein present a modified surgical approach to the ligation of LSRS via the left side of the IVC for a nine-month-old boy with severe portal hypertension and a history of Kasai portoenterostomy. LSRS was identified and exposed through the left side of the IVC and the dorsal surface of the pancreas from the superior side of the body of the pancreas. The post-operative course was uneventful with an excellent PV flow. The central approach for the ligation of LSRS is worth considering as an alternative procedure for a patient with collateral vessels and a history of multiple laparotomies.

Perioperative thrombotic complications in liver transplantation

Although the perioperative bleeding complications and the major side effects of blood transfusion have always been the primary concern in liver transplantation (OLT), the possible cohesion of an underestimated intrinsic hypercoagulative state during and after the transplant procedure may pose a major threat to both patient and graft survival. Thromboembolism during OLT is characterized not only by a complex aetiology, but also by unpredictable onset and evolution of the disease. The initiation of a procoagulant process may be triggered by various factors, such as inflammation, venous stasis, ischemia-reperfusion injury, vascular clamping, anatomical and technical abnormalities, genetic factors, deficiency of profibrinolytic activity, and platelet activation. The involvement of the arterial system, intracardiac thrombosis, pulmonary emboli, portal vein thrombosis, and deep vein thrombosis, are among the most serious thrombotic events in the perioperative period. The rapid detection of occlusive vascular events is of paramount importance as it heavily influences the prognosis, particularly when these events occur intraoperatively or early after OLT. Regardless of the lack of studies and guidelines on anticoagulant prophylaxis in this setting, many institutions recommend such an approach especially in the subset of patients at high risk. However, the decision of when, how and in what doses to use the various chemical anticoagulants is still a difficult task, since there is no common consensus, even for high-risk cases. The risk of postoperative thromboembolism causing severe hemodynamic events, or even loss of graft function, must be weighed and compared with the risk of an important bleeding. In this article we briefly review the risk factors and the possible predictors of major thrombotic complications occurring in the perioperative period, as well as their incidence and clinical features. Moreover, the indications to pharmacological prophylaxis and the current treatment strategies are also summarized.

Spleen stiffness measurements by acoustic radiation force impulse imaging after living donor liver transplantation in children: a potential quantitative index for venous complications

BACKGROUND

Living donor liver transplantation in children often results in venous complications, leading to portal hypertension. Spleen stiffness measurements have been recently proposed as a new, noninvasive parameter for portal hypertension in cirrhotic patients.

OBJECTIVE

To evaluate the diagnostic value of spleen stiffness measurements by acoustic radiation force impulse (ARFI) imaging in diagnosing venous complications after pediatric living donor liver transplantation.

MATERIALS AND METHODS

We prospectively enrolled 69 patients after pediatric living donor liver transplantation using a left-side liver allograft. Around the time of the protocol liver biopsy examination, spleen stiffness measurements by ARFI imaging were performed via the left intercostal space at the center of the spleen parenchyma and repeated five times. Imaging examinations around the time of the spleen stiffness measurements were retrospectively reviewed. Regarding venous complications, significant portal and hepatic venous stenosis was defined as >50% stenosis on multiphasic computed tomography.

RESULTS

After post hoc exclusion, 62 patients were studied. Portal and hepatic venous stenosis was identified in three and two patients, respectively. The median spleen stiffness values were 2.70 and 4.00 m/s in patients without and with venous complications, respectively (P < 0.001). Spleen stiffness measurements showed good diagnostic power for venous complications, and the cutoff value was determined as 2.93 m/s, with 100% sensitivity and 78.9% specificity. Spleen stiffness measurements decreased with the relief of venous stenosis resulting from an interventional radiology procedure.

CONCLUSION

Spleen stiffness measurements by ARFI imaging might provide a useful quantitative index for venous complications after pediatric living donor liver transplantation.

Current state of the art in management of vascular complications after pediatric liver transplantation

Vascular complications by compromising the blood flow to the allograft can have significant and sometimes life-threatening consequences after pediatric liver transplantation. High level of suspicion and aggressive utilization of diagnostic modalities can lead to early diagnosis and salvage of the allograft. This review will summarize the current trends in management of vascular complications after pediatric liver transplantation.

Novel insights into the development of portal vein thrombosis in cirrhosis patients

The prognostic impact of portal vein thrombosis (PVT) in liver cirrhosis remains controversial among studies, primarily because the risk stratification of PVT is often lacking. A definition of clinically significant PVT should be proposed and actively improved. Moreover, the risk factors for the development of PVT in liver cirrhosis should be fully recognized to screen and identify high-risk patients. Currently, well-recognized risk factors include a reduced portal vein flow velocity, a worse liver function, splenectomy, liver transplantation, and factor V Leiden and prothrombin G20210A mutations. Novel risk factors include an increased flow volume of portosystemic collateral vessel, thrombopoietin receptor agnonists, and non-selective beta-blockers. In contrast to the traditional perspectives, the abnormalities of procoagulant and anticoagulant factors may not contribute to the development of PVT in liver cirrhosis. Further studies should explore the role of other risk factors, such as antiphospholipid antibodies, methylenetetrahydrofolate reductase C677T gene mutation, hyperhomocysteinemia, and myeloproliferative neoplasms.

Analysis of factors associated with portal vein thrombosis in pediatric living donor liver transplant recipients

The technique of vascular reconstruction plays a major role in the outcome of living donor liver transplantation (LDLT). An increased use of vascular grafts (VGs) as replacements for sclerotic portal veins has become a standard technique for our group. The aim of this study was to analyze the factors associated with portal vein thrombosis (PVT) in pediatric LDLT. We performed a retrospective analysis of 486 primary pediatric LDLT procedures performed between October 1995 and May 2013. VGs used for portal reconstruction included living donor inferior mesenteric veins, living donor ovarian veins, recipient internal jugular veins, deceased donor iliac arteries, and deceased donor iliac veins. Thirty-four patients (7.0%) developed PVT. The incidence of PVT dropped from 10.1% to 2%; the overall utilization of VGs increased from 3.5% to 37.1%. In a multivariate analysis, only the use of VGs remained an independent risk factor for the occurrence of PVT (hazard ratio = 7.2, 95% confidence interval = 2.8-18.7, P < 0.001). There was no difference in survival rates between patients with PVT and patients without PVT. No patient with PVT underwent retransplantation. In conclusion, the use of VGs was independently associated with the development of PVT. Over time, there was a reduction in the incidence of early PVT in this cohort, and there was a trend toward a reduction in total PVT. The occurrence of isolated PVT in this study was not associated with decreased patient or graft survival.

Precaution against postoperative venous complications after major hepatectomy using the pedicled omental transposition flap: Report of two cases

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We report two successful cases to prevent vascular complications following hepatectomy.

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Dead space usually develops the surrounding area of major vessels following hepatectomy.

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It leads to kinking and torsion of the major vessels including portal and hepatic vein.

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We used the omental flap to fill the dead space developed adjacent to the major vessels.

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Omental flap is simple procedure and feasible to fill the dead space by its mass effect.

INTRODUCTION

Vascular complications following hepato-pancreatic biliary surgery can be devastating, and therefore precaution of them must be critical. We report two cases in which the pedicled omental transposition flap might be effective to avoid postoperative venous complications following major hepatectomy.

PRESENTATION OF CASE

Case 1 is a 80-year-old male who required to perform re-laparotomy at postoperative day 1 following major hepatectomy due to acute portal venous thrombosis (PVT). In the second surgery, the main trunk of PV was occluded by thrombus resulted from its redundancy and kinking. PV was resected with an adequate length and reconstructed. The omental flap was placed between PV and inferior vena cava (IVC) to fill in the dead space, resulting in favorable intrahepatic portal blood flow. Case 2 is a 64-year-old male who underwent left trisectionectomy because of giant hepatocellular carcinoma located close to the trunk of right hepatic vein (RHV) and IVC. After removal of the specimens, the dead space developed between the RHV and IVC. In order to prevent outflow block caused by kinking of the RHV, the omental flap was placed between the RHV and IVC, and the right triangle ligament of the liver was fixed to the diaphragm. RHV patency was confirmed by postoperative imaging.

DISCUSSION

The omental flap is a simple procedure and useful to fill the dead space developed in the area surrounding major vessels.

CONCLUSIONS

We experienced two cases in which vascular complications might be avoided by filling the dead space surrounding major vessels using the omental flap.

Long-term outcome of percutaneous transhepatic balloon angioplasty for portal vein stenosis after pediatric living donor liver transplantation: a single institute's experience

PURPOSE

To evaluate retrospectively the long-term outcomes of percutaneous transhepatic balloon angioplasty performed for portal vein stenosis (PVS) after pediatric living donor liver transplantation (LDLT).

MATERIALS AND METHODS

Between October 1997 and December 2013, of 527 pediatric patients (age < 18 y) who underwent LDLT in a single institution, 43 patients (19 boys, 24 girls; mean age, 4.1 y ± 4.1) were confirmed to have PVS at direct portography with or without manometry and underwent percutaneous interventions, including balloon angioplasty with or without stent placement. Technical success, clinical success, laboratory findings, manometry findings, patency rates, and major complications were evaluated. Follow-up periods after initial balloon angioplasty ranged from 5-169 months (mean, 119 mo).

RESULTS

Technical success was achieved in 65 of 66 sessions (98.5%) and in 42 of 43 patients (97.7%), and clinical success was achieved in 37 of 43 patients (86.0%). Platelet counts improved significantly. Of 32 patients undergoing manometry, 19 showed significant improvement of pressure gradient across the stenosis after percutaneous transhepatic balloon angioplasty. At 1, 3, 5, and 10 years after balloon angioplasty, the rates of primary patency were 83%, 78%, 76%, and 70%, and the rates of primary-assisted patency were 100%, 100%, 100%, and 96%. Two major complications subsequent to balloon angioplasty were noted: severe asthma attack and portal vein thrombosis.

CONCLUSIONS

Percutaneous transhepatic balloon angioplasty is a safe and effective treatment with long-term patency for PVS after pediatric LDLT.