Portal vein thrombosis and stenosis in pediatric liver transplantation

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.

European Society of Pediatric Radiology survey of perioperative imaging in pediatric liver transplantation: (3) postoperative imaging

BACKGROUND

Liver transplantation is the state-of-the-art curative treatment for end-stage liver disease. Imaging is a key element in the detection of postoperative complications. So far, limited data is available regarding the best radiologic approach to monitor children after liver transplantation.

OBJECTIVE

To harmonize the imaging of pediatric liver transplantation, the European Society of Pediatric Radiology Abdominal Taskforce initiated a survey addressing the current status of imaging including the pre-, intra-, and postoperative phases. This paper reports the responses related to postoperative imaging.

MATERIALS AND METHODS

An online survey, initiated in 2021, asked European centers performing pediatric liver transplantation 48 questions about their imaging approach. In total, 26 centers were contacted, and 22 institutions from 11 countries returned the survey.

RESULTS

All sites commence ultrasound (US) monitoring within 24 h after liver transplantation. Monitoring frequency varies across sites, ranging from every 8 h to 72 h in early, and from daily to sporadic use in late postoperative phases. Predefined US protocols are used by 73% of sites. This commonly includes gray scale, color Doppler, and quantitative flow assessment. Alternative flow imaging techniques, contrast-enhanced US, and elastography are applied at 31.8%, 18.2%, and 63.6% of sites, respectively. Computed tomography is performed at 86.4% of sites when clarification is needed. Magnetic resonance imaging is used for selected cases at 36.4% of sites, mainly for assessment of biliary abnormalities or when blood tests are abnormal.

CONCLUSION

Diagnostic imaging is extensively used for postoperative surveillance of children after liver transplantation. While US is generally prioritized, substantial differences were noted in US protocol, timing, and monitoring frequency. The study highlights potential areas for future optimization and standardization of imaging, essential for conducting multicenter studies.

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.

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.

Post-operative heparin reduces early venous thrombotic complications after orthotopic paediatric liver transplantation

BACKGROUND

Despite significant improvements in surgical techniques and medical care, thrombotic complications still represent the primary cause of early graft failure and re-transplantation following paediatric liver transplantation. There is still no standardized approach for thrombosis prevention.

MATERIALS AND METHODS

The study aimed to evaluate the effectiveness of early intravenous unfractionated heparin started 12 hours postoperatively at 10 UI/kg per hour and used a retrospective "before and after" design to compare the incidence of early thrombotic complications prior to (2002-2010) and after (2011-2016) the introduction of heparin in our institute.

RESULTS

From 2002 to 2016, 479 paediatric patients received liver transplantation in our institution with an overall survival rate over one year of 0.91 (95% CI: 0.87-0.94). Of 365 eligible patients, 244 did not receive heparin while 121 did receive heparin. We reported a lower incidence of venous thrombosis (VT) in the group treated with heparin: 2.5% (3/121) vs 7.9% (19/244) (p=0.038). All clinical and laboratory variables considered potential risk factors for VT were studied. By multivariate stepwise Cox proportional hazards models, heparin prophylaxis resulted significantly associated to a reduction in VT (HR=0.29 [95% CI: 0.08-0.97], p=0.045), while age <1 year was found to be an independent risk factor for VT (HR=2.62 [95% CI: 1.11-6.21]; p=0.028).

DISCUSSION

Early postoperative heparin could be considered a valid and safe strategy to prevent early VT after paediatric liver transplantation without a concomitant increase in bleeding. A future randomised control trial is mandatory in order to strengthen this conclusion.

Outcome after pediatric liver transplantation for staged abdominal wall closure with use of biological mesh-Study with long-term follow-up

Abdominal wall closure after pediatric liver transplantation (pLT) in infants may be hampered by graft-to-recipient size discrepancy. Herein, we describe the use of a porcine dermal collagen acellular graft (PDCG) as a biological mesh (BM) for abdominal wall closure in pLT recipients. Patients <2 years of age, who underwent pLT from 2011 to 2014, were analyzed, divided into definite abdominal wall closure with and without implantation of a BM. Primary end-point was the occurrence of postoperative abdominal wall infection. Secondary end-points included 1- and 5-year patient and graft survival and the development of abdominal wall hernia. In five out of 21 pLT recipients (23.8%), direct abdominal wall closure was achieved, whereas 16 recipients (76.2%) received a BM. BM removal was necessary in one patient (6.3%) due to abdominal wall infection, whereas no abdominal wall infection occurred in the no-BM group. No significant differences between the two groups were observed for 1- and 5-year patient and graft survival. Two late abdominal wall hernias were observed in the BM group vs none in the no-BM group. Definite abdominal wall closure with a BM after pLT is feasible and safe when direct closure cannot be achieved with comparable postoperative patient and graft survival rates.

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.

P4 Stump Approach for Intraoperative Portal Vein Stenting in Pediatric Living Donor Liver Transplantation: An Innovative Technique for a Challenging Problem

OBJECTIVE

The aim of this study was to evaluate the utility of the P4 stump stenting approach for treating portal vein (PV) complications in pediatric living donor liver transplantation (LDLT).

BACKGROUND

PV complications cause significant morbidity and mortality in pediatric LDLT. Biliary atresia in the backdrop of pathological PV hypoplasia and sclerosis heightens the complexity of PV reconstruction. The authors developed a novel approach for intraoperative PV stenting via the graft segment 4 PV stump (P4 stump) to address this challenge.

METHODS

From April 2009 to December 2016, 15 pediatric LDLT recipients (mean age 10.3 ± 5.0 months, mean graft-recipient weight ratio 3.70%) underwent intraoperative stenting for suboptimal PV flow (<10 cm/s) or PV occlusion after collateral ligation and graft repositioning. Under portography, metallic stents were deployed via the reopened P4 stump of the left lateral segment grafts.

RESULTS

PV diameter and peak flow increased significantly after stent placement (2.93 ± 1.74 to 7.01 ± 0.91 mm and 2.0 ± 9.2 to 17.3 ± 3.5 cm/s, respectively, P = 0.001 for both), and there were no technical failures. Stents in all surviving patients remained patent up to 8 years (mean 27.7 months), with no vascular or biliary complications. After implementation of the P4 approach, the incidence of variceal bleeding as a late complication decreased from 7% to zero.

CONCLUSION

The P4 stump stenting approach affords procedural convenience, ease of manipulation, and consistent results with the potential for excellent long-term patency in children despite continued growth. This technique obviates the need for more demanding post-transplant stenting, and may become a substitute for complicated revision surgery, portosystemic shunting, or retransplantation.

Thrombosis prophylaxis in pediatric liver transplantation: A systematic review

AIM

To review current literature of thrombosis prophylaxis in pediatric liver transplantation (PLT) as thrombosis remains a critical complication.

METHODS

Studies were identified by electronic search of MEDLINE, EMBASE and Cochrane Library (CENTRAL) databases until March 2018. The search was supplemented by manually reviewing the references of included studies and the references of the main published systematic reviews on thrombosis and PLT. We excluded from this review case report, small case series, commentaries, conference abstracts, papers which describing less than 10 pediatric liver transplants/year and articles published before 1990. Two reviewers performed study selection independently, with disagreements solved through discussion and by the opinion of a third reviewer when necessary.

RESULTS

Nine retrospective studies were included in this review. The overall quality of studies was poor. A pooled analysis of results from studies was not possible due to the retrospective design and heterogeneity of included studies. We found an incidence of portal vein thrombosis (PVT) ranging from 2% to 10% in pediatric living donor liver transplantation (LDLT) and from 4% to 33% in pediatric deceased donor liver transplantation (DDLT). Hepatic artery thrombosis (HAT) was observed mostly in mixed LDLT and DDLT pediatric population with an incidence ranging from 0% to 29%. In most of the studies Doppler ultrasonography was used as a first line diagnostic screening for thrombosis. Four different surgical techniques for portal vein anastomosis were reported with similar efficacy in terms of PVT reduction. Reduced size liver transplant was associated with a low risk of both PVT (incidence 4%) and HAT (incidence 0%, P < 0.05). Similarly, aortic arterial anastomosis without graft interposition and microsurgical hepatic arterial reconstruction were associated with a significant reduced HAT incidence (6% and 0%, respectively). According to our inclusion and exclusion criteria, we did not find eligible studies that evaluated pharmacological prevention of thrombosis.

CONCLUSION

Poor quality retrospective studies show the use of tailored surgical strategies might be useful to reduce HAT and PVT after PLT; prospective studies are urgently needed.

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.

Intra-operative portal hemodynamics in pediatric LDLT: Doppler ultrasound surveillance

Doppler ultrasonography is useful in monitoring intra-operative PV flow in LDLT. A retrospective cohort study included 550 pediatric recipients (<18 years) who underwent LDLT from October 2006 to August 2016 in our hospital. A total of 33 recipients (incidence 6%) were found to have insufficient intra-operative PV flow after PV reperfusion. The treatments included intra-operative stent placement (n=25), anticoagulation (n=3), thrombectomy and re-anastomosis (n=2), graft repositioning (n=1), collateral ligation (n=1), and replaced PV (n=1). The peak PV velocity, HAPSV, HARI, and HV velocity before and after the interventions were significantly improved 0(0,5.5) cm/s vs. 37.36±15.30 cm/s, 38.68±8.92 cm/s vs. 62.30±16.97 cm/s, 0.55±0.08 vs. 0.76±0.10, and 32.37±10.33 cm/s vs. 40.94±15.01 cm/s, respectively (P<.01). Insufficient PV flow and decreased HARI are two significant criteria indicating need for intra-operative PV management. Dramatic changes in the hepatic hemodynamics were detected after proper treatment. Immediate resolution of PV flow is feasible in pediatric LDLT.

Bleeding and thrombotic complications of pediatric liver transplant

BACKGROUND

Pediatric patients undergoing liver transplant are at significant risk for bleeding and thrombotic complications due to the complex nature of rebalanced hemostasis in patients with liver disease.

METHODS/OBJECTIVES

We reviewed records of 92 pediatric liver and multivisceral transplant cases at Duke University Medical Center between January 2009 and December 2015. The goal was to define the nature and incidence of bleeding and thrombotic complications in this cohort and define potential risk factors.

RESULTS

There were 24 major bleeding events in 19 transplants (incidence 20.7%) and 30 thrombotic events in 23 transplants (incidence 25%). Five of the 10 retransplantations were for vascular thrombotic complications. Thirty-day mortality was 4.9%, and three of these four deaths were due to vascular thrombosis. No bleeding events led to retransplantation or mortality. Prophylactic aspirin was associated with decreased risk of thrombosis without increased bleeding. Prophylactic heparin did not increase bleeding risk. Laboratory assays predicted events poorly, apparently failing to capture the nuanced and dynamic interplay between pro- and anticoagulant factors in the posttransplant patient.

CONCLUSIONS

Both bleeding and thrombosis are frequent in this population, but only thrombotic complications contributed to retransplantation and mortality. A standardized approach to coagulation testing and antithrombotic therapy may be useful in predicting and reducing adverse outcomes. Alternative approaches to monitoring hemostasis need to be prospectively investigated in this complex patient population.

Pediatric Liver Transplant: Techniques and Complications

Liver transplant is considered to be the last-resort treatment approach for pediatric patients with end-stage liver disease. Despite the remarkable advance in survival rates, liver transplant remains an intricate surgery with significant morbidity and mortality. Early diagnosis of complications is crucial for patient survival but is challenging given the lack of specificity in clinical presentation. Knowledge of the liver and vascular anatomy of the donor and the recipient or recipients before surgery is also important to avoid complications. In this framework, radiologists play a pivotal role on the multidisciplinary team in both pre- and postoperative scenarios by providing a road map to guide the surgery and by assisting in diagnosis of complications. The most common complications after liver transplant are (a) vascular, including the hepatic artery, portal vein, hepatic veins, and inferior vena cava; (b) biliary; (c) parenchymal; (d) perihepatic; and (e) neoplastic. The authors review surgical techniques, the role of each imaging modality, normal posttransplant imaging features, types of complications after liver transplant, and information required in the radiology report that is critical to patient care. They present an algorithm for an imaging approach for pediatric patients after liver transplant and describe key points that should be included in radiologic reports in the pre- and postoperative settings. Online supplemental material is available for this article. ^©RSNA, 2017.

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.

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.

Vascular complications in living donor liver transplantation at a high-volume center: Evolving protocols and trends observed over 10 years

Vascular complications continue to have a devastating effect on liver transplantation recipients, even though their nature, incidence, and outcome might have actually changed with increasing experience and proficiency in high-volume centers. The aim of this study was to analyze the trends observed in vascular complications with changing protocols in adult and pediatric living donor liver transplantation over 10 years in 2 time frames in terms of nature, incidence, and outcome. It is a retrospective analysis of 391 (group 1, January 2006 to December 2010) and 741 (group 2, January 2011 to October 2013) patients. With a minimum follow-up of 2 years, incidence of hepatic artery thrombosis (HAT) in adults has reduced significantly from 2.2% in group 1 to 0.5% in group 2 (P = 0.02). In group 2, nonsignificantly, more adult patients (75% with HAT) could be salvaged compared with only 25% patients in group 1 (P = 0.12). However, HAT in children had 100% mortality. Incidence of portal vein thrombosis (PVT) in complicated transplants in 2 eras remained the same (P = 0.2) and so has its mortality. The thrombosis rate of the neo-middle hepatic vein was significantly reduced in group 2 (P = 0.01). The incidence of HAT, particularly in adults, has decreased significantly though PVT has continued to puzzle surgeons in complicated transplants. In high-volume centers, increasing proficiency, technical modifications, early diagnosis, and multimodality of treatment is the key to decrease overall morbidity and mortality due to vascular complications. Liver Transplantation 23 457-464 2017 AASLD.

Jejunal varices diagnosed by capsule endoscopy in patients with post-liver transplant portal hypertension

Portal hypertension secondary to portal vein obstruction following liver transplant occurs in 5%-10% of children. Jejunal varices are uncommon in this group. We present a case series of children with significant GI blood loss, negative upper endoscopy, and jejunal varices detected by CE. Case series of patients who had CE for chronic GI blood loss following liver transplantation. Three patients who had their initial transplants at a median age of 7 months were identified at our institution presenting at a median age of 8 years (range 7-16 years) with a median Hgb of 2.8 g/dL (range 1.8-6.8 g/dL). Upper endoscopy was negative for significant esophageal varices, gastric varices, and bleeding portal gastropathy in all three children. All three patients had significant jejunal varices noted on CE in mid-jejunum. Jejunal varices were described as large prominent bluish vessels underneath visualized mucosa, one with evidence of recent bleeding. The results led to venoplasty of the portal vein in two patients and a decompressive shunt in one patient with resolution of GI bleed and anemia. CE is useful to diagnose intestinal varices in children with portal hypertension and GI bleeding following liver transplant.

Sonographic Evaluation of Post-transplantation Portal Vein Stenosis in Pediatric Living-donor Liver Transplant Recipients With Left-liver Grafts

INTRODUCTION

Portal vein (PV) stenosis is not uncommon in post-transplantation pediatric living-donor liver transplant (PLDLT) recipients. The purpose of this study was to identify specific ultrasound criteria that may be used to detect PV stenosis in PLDLT with left-liver grafts.

PATIENTS AND METHODS

From January 2010 to October 2014, 87 pediatric recipients underwent PLDLT with left lobes or left lateral segments at our hospital. All patients underwent routine liver Doppler ultrasound (DUS) as follow-up protocol. The morphologic narrowing and mean time averaged velocity (TAV) at the PV anastomotic site, change in anastomotic/pre-anastomotic TAV (ΔTAV), and the umbilical portal width were evaluated and analyzed. Ultrasound findings were correlated with computed tomography angiography where PV stenosis was suspected.

RESULTS

In the liver graft follow-up study, 80.4% (70 of 87 patients) of PV anastomosis was well visualized and measured by Doppler ultrasound. The optimal threshold values for TAV and ΔTAV were 49.6 cm/s and 30 cm/s, respectively, for significant PV anastomosis stenosis. In the other 19.5% (17/87), the PV anastomosis could not be identified properly. The PV anastomosis was not always visible with ultrasound; however, the optimal dilated umbilical portion of the PV indicating possible PV anastomosis narrowing threshold was umbilical portal width >1.5 cm.

CONCLUSIONS

Increased anastomotic TAV and ΔTAV are useful features for diagnosing PV stenosis. The identification of a dilated umbilical portion of the left PV helps in detection of PV stenosis in PLDLT recipients especially when the anastomotic narrowed region cannot be visualized.

Living Donor Liver Transplantation in Children: Surgical and Immunological Results in 250 Recipients at Université Catholique de Louvain

OBJECTIVES

To evaluate the outcome of pediatric living donor liver transplantation (LDLT) regarding portal vein (PV) reconstruction, ABO compatibility, and impact of maternal donation on graft acceptance.

BACKGROUND

LDLT and ABO-mismatched transplantation constitute feasible options to alleviate organ shortage in children. Vascular complications of portal hypoplasia in biliary atresia (BA) and acute rejection (AR) are still major concerns in this field.

METHODS

Data from 250 pediatric LDLT recipients, performed at Cliniques Universitaires Saint-Luc between July 1993 and June 2012, were collected retrospectively. Results were analyzed according to ABO matching and PV complications. Uni- and multivariate analyses were performed to study the impact of immunosuppression, sex matching, and maternal donation on AR rate.

RESULTS

Overall, the 10-year patient survival rate was 93.2%. Neither patient or graft loss nor vascular rejection, nor hemolysis, was encountered in the ABO nonidentical patients (n = 58), provided pretransplant levels of relevant isoagglutinins were below 1/16. In BA recipients, the rate of PV complications was lower after portoplasty (4.6%) than after truncal PV anastomosis (9.8%) and to jump graft interposition (26.9%; P = 0.027). In parental donation, maternal grafts were associated with higher 1-year AR-free survival (55.2%) than paternal grafts (39.8%; P = 0.041), but only in BA patients.

CONCLUSIONS

LDLT, including ABO-mismatched transplantation, constitutes a safe and efficient therapy for liver failure in children. In BA patients with PV hypoplasia, portoplasty seems to constitute the best technique for PV reconstruction. Maternal donation might be a protective factor for AR.

Preoperative hepatic hemodynamics in the prediction of early portal vein thrombosis after liver transplantation in pediatric patients with biliary atresia

BACKGROUND

Portal vein thrombosis (PVT) is one of the main vascular complications after liver transplantation (LT), especially in pediatric patients with biliary atresia (BA). This study aimed to assess the preoperative hepatic hemodynamics in pediatric patients with BA using Doppler ultrasound and determine whether ultrasonographic parameters may predict early PVT after LT.

METHODS

One hundred and twenty-eight pediatric patients with BA younger than 3 years of age underwent Doppler ultrasound within seven days before LT, between October 2006 and June 2013. The preoperative hepatic hemodynamic parameters were then compared between patients with early PVT (within 1 month following LT) and those without PVT. Receiver operating characteristic analysis was performed to determine the optimal cutoff value for predicting early PVT.

RESULTS

Of the 128 transplant recipients, 41 (32.03%) had a hypoplastic portal vein (PV), 52 (40.63%) had hepatofugal PV flow and 40 (31.25%) had a high hepatic artery resistance index (HARI) of ≥1. Nine cases (7.03%) experienced early PVT. A PV diameter ≤4 mm (sensitivity 88.89%, specificity 72.27%), and a hepatofugal PV flow (sensitivity 77.78%, specificity 62.18%) with a high HARI ≥1 (sensitivity 77.78%, specificity 72.27%) were hepatic hemodynamic risk factors for early PVT.

CONCLUSIONS

Hepatic hemodynamic disturbances in pediatric recipients with BA were more common. Small PV diameter (≤4 mm) and hepatofugal PV flow combined with high HARI (≥1) are strong warning signs of early PVT after LT in pediatric patients with BA. Intense monitoring of vascular patency and prophylactic thrombolytic therapy should be considered in pediatric patients undergoing LT for BA.

Pediatric transplantation: preventing thrombosis

Due to progressive advances in surgical techniques, immunosuppressive therapies, and supportive care, outcomes from both solid organ transplantation and hematopoietic stem cell transplantation continue to improve. Thrombosis remains a challenging management issue in this context, with implications for both graft survival and long-term quality of life. Unfortunately, there remains a general paucity of pediatric-specific data regarding thrombosis incidence, risk stratification, and the safety or efficacy of preventative strategies with which to guide treatment algorithms. This review summarizes the available evidence and rationale underlying the spectrum of current practices aimed at preventing thrombosis in the transplant recipient, with a particular focus on risk factors, pathophysiology, and described antithrombotic regimens.

Stent Placement for Portal Vein Stenosis After Pancreaticoduodenectomy

BACKGROUND

Portal vein (PV) stenosis is a worrisome late complication following pancreaticoduodenectomy (PD) that causes intestinal bleeding from varices, which must be diagnosed correctly and treated promptly. Recent reports advocate the usefulness of stent placement to improve PV stenosis.

METHODS

We evaluated the cause, diagnosis, and treatment method of PV stenosis after PD and the duration of stent patency in our institution.

RESULTS

Intestinal bleeding caused by PV stenosis occurred in 5 (2.4%) of 205 patients. A computed tomography scan was useful to diagnose this complication. Four of 5 patients with PV stenosis underwent percutaneous transhepatic PV stent placement. The duration of stent patency was 21-41 months, and no rebleeding occurred.

CONCLUSIONS

Percutaneous stent placement is viable, less invasive option than laparotomy for the management of PV stenosis after PD.

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.

Interventional treatment for portal venous occlusion after liver transplantation: long-term follow-up results

Portal vein (PV) occlusion after liver transplant is an uncommon clinical situation, and percutaneous interventional treatment for this condition has not been widely described. The aim of this study was to evaluate the long-term treatment effect of interventional treatment for PV occlusion after liver transplantation (LT). Follow-up data of 13 patients who received interventional treatment for PV occlusion after LT between July 2007 and April 2013 were analyzed. Of these, 10 patients had portal hypertension-related signs and symptoms. Percutaneous balloon angioplasty and stent placement were performed, with percutaneous thrombolysis treatment as appropriate. Embolization therapy was required for significant collateral circulation. Technical and clinical success, complications, and patency of PV were analyzed. Both technical and clinical success was achieved in 11 of the 13 patients (84.6%). Direct portogram showed limited PV occlusion in 7 patients and extensive PV occlusion in 4 patients. The former underwent balloon angioplasty followed by stent placement, while the latter underwent balloon angioplasty followed by stent placement and additional percutaneous thrombolysis treatment. Embolization therapy for collateral circulation was performed in all 4 patients with extensive PV occlusion and 1 patient with limited PV occlusion. All stents remained patency during the follow-up (28.5 ± 6.8 months). No portal hypertension-related symptoms reoccurred during follow-up. In conclusion, interventional treatment for PV occlusion after LT showed a high success rate and good long-term results. Comprehensive interventional treatment should be used for extensive PV occlusion.

Interventional radiology in living donor liver transplant

The shortage of deceased donor liver grafts led to the use of living donor liver transplant (LDLT). Patients who undergo LDLT have a higher risk of complications than those who undergo deceased donor liver transplantation (LT). Interventional radiology has acquired a key role in every LT program by treating the majority of vascular and non-vascular post-transplant complications, improving graft and patient survival and avoiding, in the majority of cases, surgical revision and/or re-transplant. The aim of this paper is to review indications, diagnostic modalities, technical considerations, achievements and potential complications of interventional radiology procedures after LDLT.

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.

Successful treatment by balloon angioplasty under portography for late-onset stenosis of portal vein after cadaveric liver transplantation

A 69-year-old woman, who underwent cadaveric liver transplantation for non-B, non-C liver cirrhosis with hepatocellular carcinoma in April 2009, was admitted to our hospital because of graft dysfunction. Enhanced computed tomography revealed stenosis of the left branch of the portal vein, obstruction of the right branch of the portal vein at porta hepatis, and esophagogastric varices. Balloon angioplasty of the left branch of the portal vein under transsuperior mesenteric venous portography was performed by minilaparotomy. After dilatation of the left branch of the portal vein, the narrow segment of the portal vein was dilated, which resulted in reduction of collateral circulation. At 7 days after balloon angioplasty, esophageal varices were improved. The patient made a satisfactory recovery, was discharged 8 days after balloon angioplasty, and remains well.

Portal interventions in liver transplant recipients

Portal vein interventions in liver transplant recipients represent a group of interventions in the management of several disease entities including portal vein stenosis, portal vein thrombosis, and recurrent liver cirrhosis with portal hypertension with and without gastric varices. The procedures performed in these patient populations include portal vein angioplasty with or without stent placement for portal vein stenosis, portal vein thrombolysis with or without stent placement for portal vein thrombosis, transjugular intrahepatic portosystemic shunts or splenic embolization for cirrhosis, and balloon-occluded retrograde transvenous obliteration for gastric varices. This article discusses these disease entities and the minimal invasive procedures used in their management.

Meso-Rex shunt for immediate portal revascularization in pediatric liver transplantation: first report

We describe the case of a 13-month-old girl transplanted for biliary atresia with PV hypoplasia. She received the left liver lobe of her mother and presented intraoperative portal thrombosis. Because of technical reasons, the opportunity to have conventional PV reconstruction using the donor left PV stump was lost. Immediate conversion to a meso-Rex shunt, using the recipient jugular vein as a bridge between the superior mesenteric vein and the graft Rex recessus, allowed excellent portal revascularization of the transplant. We suggest that synchronous meso-Rex shunt may constitute a valid alternative to truncal PV anastomosis during pediatric LT.

Current concepts in pediatric liver transplantation

Liver transplantation is the definitive treatment for end-stage liver disease in both children and adults. Advances over the last 2 decades have resulted in excellent patient and graft survival rates in what were previously cases of fatal disorders. These developments have been due to innovations in surgical technique, increased surgical experience, refinements in immunosuppressive regimens, quality improvements in intraoperative anesthetic management, better understanding of the pathophysiology of the liver diseases, and better preoperative and postoperative care. Remarkably, the use of split-liver and living-related liver transplantation surgical techniques has helped mitigate the well-recognized national organ shortage. This review will discuss the major aspects of pediatric liver transplantation as it pertains to indication for transplantation, recipient selection and listing for orthotopic liver transplantation, pre-orthotopic liver transplantation care of children, optimal timing of orthotopic liver transplantation, surgical technical considerations, postoperative care and complications, and patient and graft survival outcomes.

Portal vein stenosis: a rare yet clinically important cause of delayed-onset ascites after adult deceased donor liver transplantation: two case reports

Vascular complications following liver transplantation are well documented. While complications involving the portal vein are less common than the hepatic artery, portal vein complications can lead to potentially life-threatening sequelae including graft loss. Portal vein stenosis is an infrequent complication following liver transplant. The majority of these complications are seen in living donor liver transplants and pediatric liver transplants. We present 2 cases of delayed onset portal vein stenosis in adult deceased donor liver transplantation (ADDLT). The first patient presented with refractory ascites twelve months after ADDLT. He was diagnosed and successfully treated with percutaneous transhepatic portovenography and venoplasty. The second patient had a history of irradiation to his portal bed in the setting of cholangiocarcinoma. He developed refractory ascites and esophageal variceal bleeding>2 years after ADDLT. He underwent percutaneous transhepatic portovenoplasty, but eventually required placement of a portal stent due to continued problems with recurrent ascites. These 2 cases highlight the importance of considering portal vein stenosis in the differential diagnosis of late-onset ascites following liver transplantation, especially if there have been any predisposing risk factors such as portal bed irradiation or prior splenectomy.

Intra-operative management of low portal vein flow in pediatric living donor liver transplantation

For pediatric living donor liver transplantation, portal vein complications cause significant morbidity and graft failure. Routine intra-operative Doppler ultrasound is performed after graft reperfusion to evaluate the flow of portal vein. This retrospective study reviewed 65 children who had undergone living donor liver transplantation. Seven patients were detected with suboptimal portal vein flow velocity following vascular reconstruction and abdominal closure. They underwent immediate on-table interventions to improve the portal vein flow. Both surgical and endovascular modalities were employed, namely, graft re-positioning, collateral shunt ligation, thrombectomy, revision of anastomosis, inferior mesenteric vein cannulation, and endovascular stenting. The ultrasonographic follow-up assessment for all seven patients demonstrated patent portal vein and satisfactory flow. We reviewed our experience on the different modalities and proposed an approach for our future intra-operative management to improve portal vein flow at the time of liver transplantation.

Right posterior portal vein stenosis developed after living donor liver transplantation using a modified right lobe graft with a type 2 portal vein: a case report

Portal vein complications after liver transplantation (LT) can lead to graft liver failure. In this living donor liver transplantation case a stenosis developed in the right posterior branch of the portal vein of the graft liver from a living donor with type 2 portal vein variation. A 61-year-old woman diagnosed with hepatocellular carcinoma due to hepatitis B received a liver graft revealing a single lumen divided by a septum. The portal vein was anastomosed to the recipient portal vein without venoplasty. Postoperative Doppler sonogram revealed poor flow in the right posterior portal vein with compensatory arterial hyperperfusion. The postoperative computed tomography (CT) scan revealed narrowing of the proximal part of the right posterior portal vein with periportal tracking. Without intervention, the liver enzyme and bilirubin levels decreased to normal and the follow-up CT scan showed decreased periportal tracking. The patient was discharged without major complications. We believe that the posterior portal vein stenosis resulted from the direct anastomosis of the portal vein without a further venoplasty. Although there was no major complication due to the posterior portal vein stenosis in our patient, we suggest a venoplasty to prevent portal vein stenosis when using right lobe grafts with a type 2 portal vein, even if a single lumen is present and there is a margin for a direct anastomosis.

Hemodynamics of portal venous stenosis before and after treatment in pediatric liver transplantation: evaluation with Doppler ultrasound

AIM

The aim of this study was to evaluate portal vein stenosis (PVS) in pediatric liver transplantation (PLT) using Doppler ultrasound (DUS) before and after interventional management for hemodynamic changes.

MATERIALS AND METHODS

From 2000 to 2010, we encountered 11 PVS cases among 180 PLT that were evaluated using DUS and computed tomography (CT) angiography (CTA); all underwent portal stenting. DUS was used to monitor portal hemodynamics. For the diagnosis of PVS, we investigated multiple parameters including stenotic size (SS), stenotic ratio (SR) (SR [%]=PRE-SS/PRE [PRE=stenotic size]), portal flow velocity ratio (VR) (VR=VS/PRE [PRE=velocity at prestenotic site; VS=peak velocity at stenotic site]), spleen size, and platelet count.

RESULTS

The incidence of PVS was 5.6% (11/180). The PV was 2.5 mm using DUS and 2.7 mm using CTA. The average SR was 65% fitting the criterion. Low prestenotic portal flow<12 cm/sec and high peak velocity in the stenotic segment (up to 147 cm/sec) were observed in 6 cases. The VR value was high at 7.5:1 and there was splenomegaly with thrombocytopenia. After portal vein stenting, hyperperfusion occurred might after reopening the stenosis: the flow increased to an average of 34 cm/sec and then flow decreased slowly to a stable level 2 weeks later. The size of the spleen decreased from 17 to 12 cm and the thrombocytopenia also improved with platelet counts increasing from 67×10(3) to 178×10(3)/μl at 2 months follow-up. The changes in portal flow, portal vein size, spleen size, and platelet count were significant (P<.05).

CONCLUSION

PVS is diagnosed using DUS by increased intrahepatic PV dilatation, peak flow at the stenotic site, discrepant VR. Early portal stenting showed a better prognosis. DUS is essential and effective for hemodynamic monitoring and management of PVS.

Reconstruction of the middle hepatic vein tributary in adult right lobe living donor liver transplantation

BACKGROUND

In adult-to-adult living donor liver transplantation (LDLT), the use of a right lobe graft without the middle hepatic vein (MHV) can cause hepatic congestion and disturbance of venous drainage. To solve this problem, we successfully used cadaveric venous allografts preserved in 4 °C University of Wisconsin (UW) solution within 10 days as interposition veins for drainage of the paramedian portion of the right lobe in adult LDLT.

METHODS

From June 2007 to January 2008, 11 adult LDLT patients received modified right liver grafts. The major MHV tributaries (greater than 5 mm in diameter) of 9 cases were preserved and reconstructed using cadaveric interposition vein allografts that had been stored for 1 to 10 days in 4 °C UW solution. The regeneration of the paramedian sector of the grafts and the patency of the interposition vein allografts were examined by Doppler ultrasonography after the operation.

RESULTS

MHV tributaries were reconstructed in 9 recipients. Only 1 recipient died of renal failure and severe pulmonary infection on day 9 after transplantation without any hemiliver venous outflow obstruction. The other 8 recipients achieved long-term survival with a median follow-up of 30 months. The cumulative patency rates of the 8 recipients were 63.63% (7/11), 45.45% (5/11), 45.45% (5/11) and 36.36% (4/11) at 3, 6, 12 and 24 months, respectively. Regeneration of the paramedian sectors was equivalent.

CONCLUSION

The cadaveric venous allograft preserved in 4 °C UW solution within 10 days serves as a useful alternative for interposition veins in facilitating implantation of a right lobe graft and guarantees outflow of the MHV.

Impact of pre-transplant liver hemodynamics and portal reconstruction techniques on post-transplant portal vein complications in pediatric liver transplantation: a retrospective analysis in 197 recipients

BACKGROUND AND OBJECTIVE

Portal vein (PV) complications are the most frequent vascular complications in pediatric liver transplant (LT). We hypothesized that pre-LT liver hemodynamic parameters and PV reconstruction technique could predict the risk of PV complications post-LT.

METHODS

Three hundred seventy-three children had a primary LT. A detailed ultrasound study of the pre-LT native liver hemodynamics was available in 198 cases, with details of PV anastomosis available for 197 of these: end-to-end anastomosis (n = 146, 74%), interposition vein graft technique (n = 28, 14%), or portoplasty (latero-lateral anastomosis of vein graft and recipient PV) (n = 23, 12%).

RESULTS

Overall 5-year patient survival rate was 90%. Among the 198 patients with pre-LT hemodynamic data, 79 (40%) had PV hypoplasia (diameter ≤4 mm), 64 (32%) had a pathological portal flow (nonhepatopetal flow), and 47 (24%) had an arterial resistance index (ARI) ≥1. Abnormal hemodynamics were mostly observed in biliary atresia (BA). Among these 3 parameters, only ARI ≥1 was significantly correlated with a higher rate of PV complications post-LT (P = 0.041). PV complication-free survival at 5 years were 91% for end-to-end anastomosis, 91% for portoplasty, and 62% for interposition vein graft technique (P = 0.002). At multivariate analysis, the use of an interposition vein graft was the only factor to be significantly associated with a higher rate of PV complications post-LT (P = 0.003).

CONCLUSIONS

PV hypoplasia with liver hemodynamic disturbances was mainly observed in BA. Hepatic ARI ≥1 might be a good predictor of PV complications post-LT. Latero-lateral portoplasty seemed to provide the best results when end-to-end anastomosis is not feasible.

Vascular complications after living donor liver transplantation: a Brazilian, single-center experience

BACKGROUND

In living donor liver transplantation (LDLT), vascular complications are more frequently seen than in deceased donor transplantation. Early arterial, portal vein, or hepatic vein thromboses are complications that can lead to graft loss and patient death. The aim of this study was to assess the incidence, treatment, and outcome of vascular complications after LDLT in a single Brazilian center.

METHODS

Between December 2001 and December 2010, we performed 130 LDLT. Sixty-four recipients were children (27 weighing <10 kg).

RESULTS

Nine recipients had vascular complications. Hepatic artery thrombosis (HAT) occurred in 4 (3.1%), portal vein thrombosis (PVT) in 3 (2.3%), and hepatic vein thrombosis (HVT) and hepatic arterial stenosis (HAS) in 1 (0.8%) patient each. Complications were identified by Doppler and confirmed by angiography or angiotomography. Patients with HAT were listed for retransplantation. One died before retransplant. Two children were submitted to retransplantation; one is still alive, with neurologic sequelae. One adult with HAT was retransplanted with a deceased donor graft and is doing well 58 months after surgery. Two patients with PVT died as a consequence of graft malfunction. In the other case, portal vein arterialization was performed, but patient died 11 months posttransplant. HVT was detected after cardiac reanimation and was treated with an endovascular stent. This patient died 3 months after LDLT. HAS was diagnosed after liver abscess development and was successfully treated by endovascular angioplasty. No recurrence was observed after 22 months. Follow-up ranged from 9 to 117 months.

CONCLUSION

Pediatric patients are more prone to develop vascular complications after LDLT. Long-term survival was statistically lower for recipients with vascular complications (33.3% vs 77.7%; P = .008).

Risk factors for portal vein complications in pediatric living donor liver transplantation

BACKGROUND

Portal vein (PV) complications in pediatric living donor liver transplantation (LDLT) are often asymptomatic in the early stages after transplantation and can be serious enough to lead to graft failure. There have been few reports on risk factors for PV complications in LDLT. The aim of this study is to investigate the influence of hepatic inflow upon PV complications and to predict patients at risk for these complications.

MATERIAL/METHOD

From 1997 to 2008, 46 pediatric patients underwent LDLT at our center. Portal venous and hepatic arterial flows and PV diameter were analyzed.

RESULTS

PV complications were identified in seven patients (15.2%) and occurred at a younger age and lower weight. As a result of appropriate treatment, none of the patients suffered graft failure. Analysis of the 46 patients and 27 patients under two yr of age identified smaller PV diameter in recipient and larger discrepancy of PV diameter as risk factors. Portal venous flow tended to be low, in contrast to hepatic arterial flow, which tended to be high.

CONCLUSION

PV size strongly influences PV complications. Other factors such as younger age, low portal venous flow, and high hepatic arterial flow may be risk factors for PV complications.

Can Doppler sonography discern between hemodynamically significant and insignificant portal vein stenosis after adult liver transplantation?

OBJECTIVE

The purpose of our study was to determine whether Doppler sonography, using a strict reference standard, can specifically identify hemodynamically significant portal vein anastomotic stenosis after liver transplantation in adults.

MATERIALS AND METHODS

The duplex and color Doppler examinations of 13 consecutive adult patients who underwent portal venography for suspected portal vein stenosis after liver transplantation were retrospectively examined. Peak systolic velocity (PSV) and change in PSV (ΔPSV) along the portal vein were correlated with portal venography. Stenoses above 50% on the basis of strict venographic criteria were considered hemodynamically significant. The Doppler studies before and after intervention were also assessed. Fourteen randomly chosen subjects with transplants without suspicion of portal anastomotic stenosis acted as controls.

RESULTS

Six patients had significant portal vein stenosis (> 50%) and seven had stenosis below 50%. PSV and ΔPSV were significantly greater for patients with > 50% stenosis in comparison with those with ≤ 50% stenosis and control subjects. Optimal threshold values for PSV and ΔPSV were 80 and 60 cm/s, respectively, with either value alone yielding sensitivity of 100% and specificity of 84% for significant stenosis. Threshold values also included cases of stenosis below 50%. Five of six patients with > 50% stenosis underwent stenting, with poststent PSV and ΔPSV significantly declining to match that of control subjects. Three of seven with stenosis below 50% had stents placed but no significant change in the Doppler examination.

CONCLUSION

Doppler threshold criteria reliably exclude those without posttransplantation portal vein stenosis and have high sensitivity for detecting portal stenosis. However, these criteria cannot discern the extent of stenosis.

Transsplenic endovascular therapy of portal vein stenosis and subsequent complete portal vein thrombosis in a 2-year-old child

A complex catheter intervention for portal vein stenosis and subsequent complete thrombosis after split-liver transplantation was performed using transsplenic access to the portal vein circulation. The combination of intrahepatic, local thrombolysis and extrahepatic portal vein angioplasty performed twice on 2 consecutive days followed by anticoagulation with a high dose of heparin and clopidogrel completely resolved portal vein stenosis and thrombosis. Postinterventional angiographic and serial ultrasound examinations confirmed that the endovascular therapy was successful. In selected patients, percutaneous transsplenic access to the portal vein circulation may be used for diagnostic and therapeutic interventions even in early childhood.

Incidence, impact, and treatment of portal and hepatic venous complications following pediatric liver transplantation: a single-center 12 year experience

PVT or PVS and HVOO are known causes of graft and patient loss after pediatric liver transplantation. Increased incidences of these complications have been reported in partial livers including DDSLT or LDLT. From 1997 to 2008, 241 consecutive pediatric patients received 271 hepatic grafts at a single center. Median follow-up is 1856 days. Surgical technique, demographics, lab values, and radiologic imaging procedures were obtained utilizing OTTR to evaluate the relationship of portal and hepatic complications with risk factors, patient and graft survival. Grafts were composed of 115/271 (42.4%) partial livers of which 90 (33.2%) were DDSLT and 25 (9.2%) LDLT. Of 271 patients, 156 (57.6%) received whole-sized grafts. There were six PVC in five patients with one patient requiring retransplantation (0.34%) and no patient deaths. Utilizing all three hepatic vein orifices on the recipient hepatic vena cava and the donor hepatic vein cut short enables a wide hepatic outflow tract unlikely to twist. None of the 241 patients developed early or late complications of the hepatic vein. None of the last 128 consecutive patients who received 144 grafts over seven and a half yr have developed either early or late complications of the hepatic or portal vein. Partial-graft actuarial survival was similar to whole-graft survival (87.2% vs. 85.3% at one yr; 76.6% vs. 80.2 at three yr; p = 0.488). Likewise, patient survival was similar between partial grafts and whole grafts (93.8% vs. 93.1% at one yr; 89.8% vs. 87.2% at three yr; p = 0.688) with median follow-up of 1822 (+/-1334) days. Patients receiving partial livers were significantly younger and smaller than patients receiving whole livers (p < 0.001). Portal and hepatic venous complications may have negative effects on patient or graft survival after pediatric liver transplantation. In our series, there was one graft and no patient loss related to portal or hepatic venous complications after pediatric liver transplantation over 12 yr.

Thrombotic events after pediatric liver transplantation

TE may contribute to morbidity and mortality after LT. The objectives were to determine the incidence of early TE post-pediatric LT and compare differences between children with and without TE. A retrospective review of 88 transplanted children (January 2002-October 2007) was performed to determine the incidence of Doppler-confirmed DVT and ATE in the first month post-LT. Fourteen (16%) patients developed TE: DVT in seven (8%) and ATE in seven (8%) patients. Six of 88 (6.8%) developed symptomatic CVL-related DVT. Median (range) time post-LT to DVT and ATE were 7 (4-18) and 8 (1-31) days, respectively. There was no significant difference in age/body weight at LT between patients with or without DVT and ATE. There was no significant difference between patients with or without HAT in age and weight at LT, cold ischemic time, duration of surgery, hematocrit levels, whole-organ graft type, intraoperative FFP, high-risk CMV status, or early acute cellular rejection. In conclusion, the incidence of early TE post-pediatric LT was 16%, including DVT in 8%. Prospective studies are necessary to evaluate the role of prophylactic anticoagulation and potential modifiable risk factors post-pediatric LT.

Vascular stents in the management of portal venous complications in living donor liver transplantation

To evaluate the efficacy of stent placement in the treatment of portal vein (PV) stenosis or occlusion in living donor liver transplant (LDLT) recipients, 468 LDLT records were reviewed. Sixteen (10 PV occlusions and 6 stenoses) recipients (age range, 8 months-59 years) were referred for possible interventional angioplasty (dilatation and/or stent) procedures. Stent placement was attempted in all. The approaches used were percutaneous transhepatic (n = 10), percutaneous transsplenic (n = 4), and intraoperative (n = 2). Technical success was achieved in 11 of 16 patients (68.8%). The sizes of the stents used varied from 7 mm to 10 mm in diameter. In the five unsuccessful patients, long-term complete occlusion of the PV with cavernous transformation precluded catherterization. The mean follow-up was 12 months (range, 3-24). The PV stent patency rate was 90.9% (10/11). Rethrombosis and occlusion of the stent and PV occurred in a single recipient who had a cryoperserved vascular graft to reconstruct the PV during the LDLT operation. PV occlusion of >1 year with cavernous transformation seemed to be a factor causing technical failure. In conclusion, early treatment of PV stenosis and occlusion by stenting is an effective treatment in LDLT. Percutaneous transhepatic and transsplenic, and intraoperative techniques are effective approaches depending on the situation.