Pediatric liver transplantation: a pictorial essay of early and late complications

Determinants of early surgical complications after pediatric liver transplantation: A single center/single surgeon experience over 20 years

BACKGROUND

The risk of early surgical complications of liver transplantation (LT) is higher in children when compared with adults. The aims of the present retrospective study from a single center cohort/single surgeon were to identify the predictive factors for surgical complications after pediatric LT.

METHODS

All children receiving a first LT from October 1990 to October 2010 in our center were included.

RESULTS

Included 151 children (boys 55.0%), with a mean age of 4.8 ± 4.8 years, and a mean weight of 17.9 ± 14.4 kg. Thirty-seven patients were transplanted within the first year, and 59 patients had a body weight below 10 kg. The main initial liver disease was biliary atresia (49.0%). Living donor LT was performed in 39 cases (25.8%), cadaveric whole liver LT in 50 cases (33.1%), and cadaveric partial liver LT in 62 cases (41.1%). Early surgical complications included reoperation (37.8%), vascular complications (8.6%), i.e. arterial (3.3%) or portal thrombosis/stenosis (7.3%) within the first month, and biliary complications in the first 90 days occurred in 22.5% of the cases. The main indications for surgical revision were abdominal bleeding, treatment of a biliary complication, and bowel perforation. Multivariate analysis disclosed that only graft type (split and moreover from a living donor) was significantly and independently associated with the occurrence of biliary complication, and that indication for LT, period, graft type, and operative time were significantly and independently associated with the necessity of surgical revision.

CONCLUSION

Our results emphasize that surgical complications are frequent and strongly depend on patient/graft characteristics.

Current Endovascular Management of Arterial Complications After Pediatric Liver Transplantation in a Tertiary Center

PURPOSE

Pediatric liver transplant surgery is burdened by arterial complications whose endovascular treatment is not standardized. We report the outcomes of a cohort of pediatric recipients with hepatic artery complications treated by endoluminal procedures.

MATERIALS AND METHODS

From December 2019 to December 2022, consecutive transplanted pediatric patients who underwent endovascular treatment of hepatic artery complications were reviewed. The analysis included: type of complication (occlusion, stenosis, pseudoaneurysm); onset (acute =  < 15 days, subacute = 15-90 days, late =  > 90 days); endovascular technique (angioplasty, stenting); complications and outcomes. Technical success was defined as the opacification of the hepatic artery at the final angiogram with < 50% residual stenosis and no pseudoaneurysms. Clinical success was defined by graft's and patient's survival.

RESULTS

Seventeen patients (8 males; median age 33 months, IQR 9-103) underwent 21 hepatic arteriography procedures for predominantly acute or subacute occlusions (n = 7) or stenosis (n = 11) with concurrent pseudoaneurysms (n = 4). Primary and secondary technical success was achieved in 13/18 and 3/3 procedures, respectively, with overall technical success of 76%. Angioplasty alone was successful in 5/21 procedures; stent-retriever thrombectomy was performed in one occlusion with thrombosis; stenting was required in 9/17 (53%) patients. Clinical success was obtained in 14/17 (82%) patients with hepatic artery patency after a median of 367 days (IQR 114.5-500). Clinical failure occurred in 3 permanent occlusions, with 2 deaths and 1 re-transplantation. Procedure-related complications included minor events in 3/17 (18%) patients and 1/17 (6%) death.

CONCLUSION

In liver transplanted children with hepatic artery complications, endovascular treatment may provide clinical success, with stenting often required in acute and subacute conditions.

LEVEL OF EVIDENCE

Level 4.

Venous outflow obstruction in pediatric left lateral segment split liver transplantation

BACKGROUND

Venous outflow obstruction (VOO) is a known cause of graft and patient loss after pediatric liver transplantation (LT). We analyzed the incidence, risk factors, diagnosis, management, and outcome of VOO in a large, consecutive series of left lateral segment (LLS) split LT with end-to-side triangular venous anastomosis.

METHODS

We evaluated data collected in our prospective databases relative to all consecutive pediatric liver transplants performed from January 2006 to December 2021. We included in this study children undergoing LLS split liver transplant with end-to-side triangular anastomosis. Diagnosis of VOO was based on clinical suspicion and radiological confirmation.

RESULTS

VOO occurred in 24/279 transplants (8.6%), and it was associated with lower graft weight (p = .04), re-transplantation (p = .008), and presence of two hepatic veins (p < .0001). In presence of two segmental veins' orifices, the type of reconstruction (single anastomosis after venoplasty or double anastomosis) was not significantly related to VOO (p = .87). Multivariable analysis indicated VOO as a risk factor for graft lost (hazard ratio 3.21, 95% confidence interval 1.22-8.46; p = .01). Percutaneous Transluminal Angioplasty (PTA) was effective in 17/22 (77%) transplants. Surgical anastomosis was redone in one case. Overall six grafts (25%) were lost.

CONCLUSION

VOO after LLS split LT with end-to-side triangular anastomosis is an unusual but critical complication leading to graft loss in a quarter of cases. The occurrence of VOO was associated with lower graft weight, re-transplantation, and presence of two hepatic veins. PTA was safe and effective to restore proper venous outflow in most cases.

Vascular Complications After Liver Transplantation

OBJECTIVES

Vascular complications after liver transplant can be lethal. High levels of suspicion and aggressive use of diagnostic tools may help with early diagnosis and treatment. Here, we share our experiences regarding this topic.

MATERIALS AND METHODS

Adult and pediatric patients who had liver transplant between February 1997 and June 2018 in our clinic were included in the study. Patients were grouped according to age (pediatric patients were those under 18 years old), male versus female, indication for transplant, type of liver transplant, type of vascular complication, treatment, and survival aftertreatment.We analyzed the statistical incidence of vascular complications according to age, male versus female, and type of liver transplant.

RESULTS

Our analyses included 607 liver transplant procedures, including 7 retransplants, with 349 (57.4%) from living donors and 258 (42.6%) from deceased donors. Of total patients, 539 were adults (89.8%) and 61 were children (10.2%). Vascular complications occurred in 25 patients (4.1%), with hepatic artery complications seen in 13 patients (2.1%) (10 adults [1.8%] and 3 children [4.9%]), portal vein complications seen in 9 patients (1.5%) (6 adults [1.1%] and 3 children [4.9%]), and hepatic vein complications seen in 3 patients (0.5%) (2 adults [0.36%] and 1 child [1.6%]). Rate of vascular complications was statistically higher in pediatric patients (11.4% vs 3.3%; P = .007) and higher but not statistically in recipients of livers from living donors (5.2% vs 2.7%; P = .19). Twelve patients (48.8%) were treated with endovascular approach, and 11 (0.44%)required surgicaltreatment. Two patients underwent immediate retransplant due to hepatic artery thrombosis.

CONCLUSIONS

Because vascular complications are the most severe complications afterlivertransplant,there must be close follow-up of vascular anastomoses, particularly early postoperatively, with radiologic methods. In cases of vascular complications, emergent treatment, including endovascular interventions, surgery, and retransplant, must be performed.

Doppler Ultrasound of Vascular Complications After Pediatric Liver Transplantation: Incidence, Time of Detection, and Positive Predictive Value

Purpose Doppler ultrasound (DUS) is widely used to detect vascular complications after pediatric liver transplantation (LT). This study aimed to assess the moment of first detection of vascular complications with DUS, and to determine the positive predictive value (PPV) of DUS.

Materials and Methods Patients aged 0–18 years who underwent LT between 2015 and 2019 were retrospectively included. 92 LTs in 83 patients were included (median age: 3.9 years, interquartile range: 0.7–10.5). Patients underwent perioperative (intra-operative and immediately postoperative) and daily DUS surveillance during the first postoperative week, and at 1, 3, and 12 months. Vascular complications were categorized for the hepatic artery, portal vein, and hepatic veins. DUS findings were compared to surgical or radiological findings during the 1-year follow-up.

Results 52 vascular complications were diagnosed by DUS in 35/92 LTs (38%). 15 out of 52 (28.8%) were diagnosed perioperatively, 29/52 (55.8%) were diagnosed on postoperative days 1–7, and 8/52 (15.4%) after day 7. The PPV for all vascular complications diagnosed with DUS was 92.3%. During the 1-year follow-up, 18/19 (94.7%) hepatic artery complications, 19/26 (73.1%) portal vein complications, and 7/7 (100%) hepatic vein complications were diagnosed perioperatively or during the first week.

Conclusion The majority of vascular complications during the first year after pediatric LT were diagnosed by DUS perioperatively or during the first week, with a high PPV. Our findings provide important information regarding when to expect different types of vascular complications on DUS, which might improve DUS post-LT surveillance protocols.

Evaluation and management of biliary complications after pediatric liver transplantation: pearls and pitfalls for percutaneous techniques

In pediatric liver transplantation, bile duct complications occur with a greater incidence than vascular anastomotic dysfunction and represent a major source of morbidity and mortality. While surgical re-anastomosis can reduce the need for retransplantation, interventional radiology offers minimally invasive and graft-saving therapies. The combination of small patient size and prevailing Roux-en-Y biliary enteric anastomotic techniques makes endoscopic retrograde cholangiopancreatography difficult if not impossible. Expertise in percutaneous management is therefore imperative. This article describes post-surgical anatomy, pathophysiology and noninvasive imaging of biliary complications. We review percutaneous techniques, focusing heavily on biliary access and interventions for reduced liver grafts. Subsequently we review the results and adverse events of these procedures and describe conditions that masquerade as biliary obstruction.

Assessment of hepatic artery anatomy in pediatric liver transplant recipients: MR angiography versus CT angiography

During LT screening, children undergo CTA to determine hepatic artery anatomy. However, CTA imparts radiation, unlike MRA. The aim was to compare MRA to CTA in assessing hepatic artery anatomy in pediatric LT recipients. Twenty-one children (median age 8.9 years) who underwent both CTA and fl3D-ce MRA before LT were retrospectively included. Interreader variability between 2 radiologists, image quality, movement artifacts, and confidence scores, were used to compare MRA to CTA. Subgroup analyses for ages <6 years and ≥6 years were performed. Interreader variability for MRA and CTA in children <6 years was comparable (k = 0.839 and k = 0.757, respectively), while in children ≥6 years CTA was superior to MRA (k 1.000 and k 0.000, respectively). Overall image quality and confidence scores of CTA were significantly higher compared to MRA at all ages (2.8/3 vs. 2.3/3, p = .001; and 2.9/3 vs. 2.5/3, p = .003, respectively). Movement artifacts were significantly lower in CTA compared to MRA in children ≥6 years (1.0/3 vs. 1.7/3, p = .010, respectively). CTA is preferred over fl3D-ce MRA for the preoperative assessment of hepatic artery anatomy in children receiving LT, both at ages <6 years and ≥6 years.

Catastrophic Brain Aspergillosis after Liver Transplantation

Background. Liver transplantation has many complications. Because of receiving immunosuppressive regimens, infectious complications in these patients may have fatal results. Aspergillosis in solid organ recipients is one of the most common fungal infections that usually occur 1 month after transplantation. Aspergillus infection mainly involves the lungs. Although the central nervous system may get involved due to hematogenous spreading from lungs, isolated central nervous system involvement is rarely reported. Case Presentation. The patient was an 8-year-old boy, with a case of Wilson disease, who underwent liver transplantation due to acute fulminant hepatic failure. Four days after the surgery, he was affected by fever, agitation, loss of consciousness, hemiparesis, and focal seizure. Brain MRI showed abscess formation, whereas chest X-ray was normal. Intravenous antibiotics were initiated but the patient's condition was not improving; therefore, surgical drainage of the abscess was performed. The pathological investigation was compatible with aspergillosis. Antifungal therapy with voriconazole was administrated. His symptoms were resolved but unfortunately, brain lesions caused persistent vegetative state. Discussion. Aspergillus is a ubiquitous organism that mainly occurs in immunocompromised patients. Aspergillosis could be prevented by environmental modification such as installing high-efficiency particulate air filters. Chemoprevention with triazoles, echinocandins, and polyenes is also effective. Voriconazole is the drug of choice for aspergillosis treatment. Although voriconazole is a highly effective antifungal drug, cerebral aspergillosis is often fatal.

Sonography of liver transplantation

Orthotopic liver transplant (OLT) is established as the definitive treatment of choice for end stage liver disease. Over the years, refined surgical techniques as well as advancements in organ preservation and immunosuppressive regimens have improved graft and patient survival rates. Imaging has also contributed to improved graft and patient survival. Ultrasound is the initial investigation of choice for evaluation of post-transplant anatomy and for identifying early complications. A thorough knowledge of surgical techniques and normal post-operative appearance of the OLT is needed to accurately identify and characterize graft complications. The objective of this article is to review the sonographic findings of normal liver transplant as well as post-operative complications. Indications and contraindications for OLT as well as different surgical techniques will also be briefly reviewed.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Abdominal Applications of Pediatric Body MR Angiography: Tailored Optimization for Successful Outcome

OBJECTIVE. The purpose of this article is to summarize current common techniques and indications for pediatric abdominopelvic MR angiography and strategies for optimizing them to achieve successful outcomes. We also discuss newer MR angiography techniques, including whole-body imaging and blood pool contrast agents, as well as various approaches to reducing the need for anesthesia in pediatric MRI. CONCLUSION. Pediatric body vascular imaging presents a unique set of challenges that require a tailored approach. Emerging pediatric abdominopelvic MR angiography techniques hold promise for continued improvement in pediatric body MR angiography.

Imaging Assessment of Complications from Transplantation from Pediatric to Adult Patients: Part 1: Solid Organ Transplantation

End-stage organ failure is commonly treated with transplantation of the respective failing organ. Although outcomes have progressively improved over the decades, early and late complications do occur, and are often diagnosed by imaging. Given the increasing survival rates of transplant patients, the general radiologist may encounter these patients in the outpatient setting. Awareness of the normal radiologic findings after transplantation, and imaging findings of the more common complications, is therefore important. We review and illustrate the imaging assessment of complications from lung, liver, and renal transplantation, highlighting the key similarities and differences between pediatric and adult patients.

Persistence of post-operative color Doppler abnormalities is linked to reduced graft survival in pediatric patients after liver transplantation

Color Doppler US is a readily available imaging modality for the evaluation of liver transplants. The aim of our study was to evaluate the temporal course of color Doppler US findings in children after LTX and to investigate the effect of resolving and persisting abnormalities during follow-up on long-term outcome. All children who underwent LTX during January 2000 until December 2003 (155 LTX in 137 patients, 75 male and 62 female; mean age at LTX 4.1 ± 4.8 years; range, 0.1-16.3 years) were retrospectively evaluated. Following a predefined ultrasound protocol with prospective documentation, intraoperative, post-operative, and follow-up examinations were evaluated for color Doppler abnormalities. The time of occurrence and temporal course of the findings were recorded. Graft survival rates and graft survival times were compared. Abnormal color Doppler US examinations were noted in 98 of 155 grafts during the entire observational period (63.2%). In 57 of 98 grafts (58.2%), abnormalities were limited to the perioperative period (<30 days after LTX). Survival of grafts with transient perioperative abnormalities was similar to transplantations with regular color Doppler US examinations (graft survival rates, 80.7% vs 84.2%, P = .622; mean graft survival time, 2596.92 vs 2511.40 days, P = .67). Grafts with persisting color Doppler US abnormalities in the follow-up period (>30 days after LTX; 37/98 LTX, 37.8%) showed reduced survival compared with regular courses (graft survival rate 62.2% vs 80.7%, P = .047), indicating underlying organ-specific alterations. Standardized longitudinal evaluation during the perioperative and the follow-up period can enhance the prognostic capabilities of color Doppler US in children following LTX.

Pediatric Hepatobiliary Interventions in the Setting of Intrahepatic Vascular Malformations, Portal Hypertension, and Liver Transplant

Within the broad spectrum of pediatric hepatobiliary disorders, hepatic vascular malformations, portal hypertension, and hepatic transplant interventions pose numerous challenges. The role of interventional radiology within each of these conditions is discussed herein, beginning with endovascular management of high flow hepatic vascular malformations. Next, while becoming less common in adult populations, surgical portoportal and portosystemic shunts remain prevalent in many pediatric centers. Shunt anatomy is reviewed along with endovascular management techniques for shunt dysfunction. Next, the growing experience with pediatric transjugular intrahepatic portosystemic shunt placement is reviewed along with tips for success in pediatric patients. Finally, pediatric hepatic transplant interventions are discussed with technical notes pertinent to split liver anatomy.

Successful percutaneous treatment of biliary stenosis after living donor liver transplantation in a child

We report the case of a 16-year-old boy with primary sclerosing cholangitis associated with inflammatory bowel disease who was initially treated and controlled pharmacologically. He underwent living donor liver transplantation (LDLT) after he developed progressive biliary tract abnormalities and portal hypertension accompanied by recurrent bile duct infections. Two months following LDLT, the hepaticojejunostomy anastomosis became occluded and it was treated surgically. Few weeks later, an increase in drain production persisted without focus; therefore, further diagnostic tests were conducted which proved the recurrence of biliary cast. Under sonographic guidance, external drainage of bile was carried out by percutaneous transhepatic cholangiography and drainage. In total, our patient underwent 5 interventions under general anesthesia and clinically, our patient's general condition improved, and he gained weight. Minimally invasive procedures such as percutaneous transhepatic cholangiography and drainage and balloon dilation are safe and effective, but may require several attempts before being successful.

Portal Venous Flow Alterations in Hepatic Artery Thrombosis Following Liver Transplant

OBJECTIVES

The hepatic vasculature is a unique system due to a dual supply that includes the hepatic artery and portal vein, which interact when the liver vascular supply is decreased. Hepatic artery buffer response, an intrinsic regulatory mechanism that compensates for blood supply, maintains increased hepatic artery flow and caliber in response to portal vein failure. Previous studies revealed that portal vein flow showed no alterations to establish adequate blood supply in response to hepatic artery occlusion. Here, we analyzed portal vein flow changes in patients with hepatic artery thrombosis after liver transplant.

MATERIALS AND METHODS

From December 1988 to October 2017, our center performed 580 liver transplant procedures. Those diagnosed with hepatic artery thrombosis (19 females, 24 males) by Doppler ultrasonography during postoperative week 1 were analyzed. Patients received either surgery or endovascular treatment for hepatic artery thrombosis, with patency confirmed by Doppler ultrasonography. We compared portal vein flow velocity and caliber before and after treatment using Wilcoxon signed rank and Mann Whitney U tests.

RESULTS

Mean patient age was 18.9 ± 21.4 years. Portal vein flow velocity pretreatment (median of 70 cm/ s) was significantly higher than posttreatment (median of 52 cm/ s) in all patients (P < .001). Median flow velocity decreased significantly after treatment when subgroups were compared, including age (adult vs child), transplant type (orthotopic transplant vs living donor), and treatment (surgery vs endovascular). However, portal vein flow velocity showed a significantly higher decrease in the surgery subgroup than in the endovascular treatment subgroup (P = .018). There was no significant relationship between portal vein calibers before and after treatment (P = .36).

CONCLUSIONS

The significant decrease in portal vein flow velocity after successful treatment of hepatic artery thrombosis may represent a compensatory flow change of the portal vein in response to diminished hepatic artery flow.

Doppler ultrasound in the diagnosis of Budd-Chiari syndrome in children after split liver transplantation

PURPOSE

To assess the capabilities of a velocity ratio>3 for the diagnosis of Budd-Chiari syndrome (BCS) in children after split liver transplantation using Doppler ultrasonography (DUS).

MATERIALS AND METHODS

A total of 28 children who underwent liver transplantation using a split procedure were included. There were 11boys and 17girls with a mean age of 3.8years (range: 0.7-12years). Velocity ratio between blood velocity upstream of the anastomosis and that at the level of the inferior vena cava anastomosis was calculated. Sensitivity, specificity and accuracy of DUS for the diagnosis of BCS were estimated using a velocity ratio>3.

RESULTS

Eight children (8/28; 29%) had BCS and 20 (20/28; 71%) did not have BCS using the standard of reference. A velocity ratio>3 on DUS yielded 88% sensitivity (95% CI: 53-98%), 80% specificity (95% CI: 58-92%) and 82% accuracy (95% CI: 64-92%) for the diagnosis of BCS.

CONCLUSION

A velocity ratio>3 on DUS is a reliable finding for the diagnosis of BCS in children after split liver transplantation.

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.

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.

Simplified split-bolus intravenous contrast injection technique for pediatric abdominal CT

PURPOSE

To investigate pediatric abdominal CT using a simplified split-bolus (Split group) contrast injection compared with a single bolus (Control group).

METHODS

Radiation dose, image quality and diagnostic accuracy were compared.

RESULTS

Split group demonstrated lower effective dose (2.46 vs. 2.85mSv, p=0.002) and noise levels in aorta, liver and portal vein (p<0.001). There was one false-negative case of portal vein obliteration in the Split group.

CONCLUSIONS

A simple method of split-bolus intravenous contrast injection technique can provide adequate and homogeneous enhancement in pediatric abdominal CT.

Benign Biliary Strictures

Differentiating benign and malignant biliary strictures is a challenging and important clinical scenario. The typical presentation is indolent and involves elevation of liver enzymes, constitutional symptoms, and obstructive jaundice with or without superimposed or recurrent cholangitis. While overall the most common causes of biliary strictures are malignant, including cholangiocarcinoma and pancreatic adenocarcinoma, benign strictures encompass a wide spectrum of etiologies including iatrogenic, autoimmune, infectious, inflammatory, and congenital. Imaging plays a crucial role in evaluating strictures, characterizing their extent, and providing clues to the ultimate source of biliary obstruction. While ultrasound is a good screening tool for biliary ductal dilatation, it is limited by a poor negative predictive value. Magnetic resonance cholangiopancreatography is more than 95% sensitive and specific for detecting biliary strictures with the benefit of precise anatomic localization. Other commonly employed imaging modalities include endoscopic retrograde cholangiopancreatography with endoscopic ultrasound, contrast-enhanced CT, and cholangiography. First-line treatment of benign biliary strictures is endoscopic dilation and stenting. In patients with anatomy that precludes endoscopic cannulation, percutaneous biliary drain insertion and balloon dilation is preferred.

Vascular complications after adult living donor liver transplantation: Evaluation with ultrasonography

Living donor liver transplantation (LDLT) has been widely used to treat end-stage liver disease with improvement in surgical technology and the application of new immunosuppressants. Vascular complications after liver transplantation remain a major threat to the survival of recipients. LDLT recipients are more likely to develop vascular complications because of their complex vascular reconstruction and the slender vessels. Early diagnosis and treatment are critical for the survival of graft and recipients. As a non-invasive, cost-effective and non-radioactive method with bedside availability, conventional gray-scale and Doppler ultrasonography play important roles in identifying vascular complications in the early postoperative period and during the follow-up. Recently, with the detailed vascular tracing and perfusion visualization, contrast-enhanced ultrasound (CEUS) has significantly improved the diagnosis of postoperative vascular complications. This review focuses on the role of conventional gray-scale ultrasound, Doppler ultrasound and CEUS for early diagnosis of vascular complications after adult LDLT.

Regenerative liver surgeries: the alphabet soup of emerging techniques

New surgical procedures taking advantage of the regenerative abilities of the liver are being introduced as potential curative therapies to these patients either to provide auxiliary support while the native liver recovers or undergoes hypertrophy. For patients with hepatocellular carcinoma outside of the Milan criteria or bilobar colorectal metastases liver transplantation is not an option. Fulminant hepatic failure can be treated but requires life-long immunosuppression. These complex surgical procedures require high quality and directed imaging.

Long-term outcome of endovascular intervention in hepatic venous outflow obstruction following pediatric liver transplantation

The purpose of our study was to address the long-term outcome of angioplasty and stent placement for hepatic venous outflow obstruction following pediatric liver transplantation. From October 1999 to December 2011, 20 stenotic lesions were confirmed to constitute hepatic venous outflow obstruction in 18 pediatric patients (13 boys, 5 girls) among 152 pediatric patients following liver transplantation and were managed with endovascular intervention. Stent placement was favored over additional angioplasty in patients of preadolescent or adolescent age (>8 years old), after 1 or 2 sessions of balloon angioplasty. The primary patency and assisted primary patency were estimated using the Kaplan-Meier method. A total of 32 procedures (24 balloon angioplasties, 8 stent placements) were conducted. The technical success rate was 90.6% (29/32). Clinical success was achieved in 15 of 18 patients (clinical success rate of 83.3%). Major complications did not occur in our study. Median follow-up was 91.5 months (interquartile range, 54.7-137.3 months) for the 18 patients. The 1-year, 3-year, 5-year, and 10-year primary patencies of the 20 treated lesions were 63.5%, 57.8%, 57.8%, and 57.8%, respectively. The 1-year, 3-year, 5-year, and 10-year assisted-primary patencies of the lesions were 100%, 100%, 100%, and 100%, respectively. Of the 6 patients of preadolescent or adolescent age, 5 patients underwent stent placement procedures, and the stents were patent during the follow-up period of 57.3-162.5 months (median, 72.7 months). In conclusion, endovascular intervention is very effective in hepatic venous outflow obstruction following pediatric liver transplantation. In addition, early stent placement in patients of preadolescent or adolescent age can provide a safe and favorable long-term outcome.

Ultrasonography, laboratory, and cholangiography correlation of biliary complications in pediatric liver transplantation

The aim of this study is to correlate the US, laboratory, and cholangiography findings in pediatric liver transplant patients with biliary complications, trying to identify reliable decision-making tools for the management of these complications. Retrospective review was carried out of US results in 39 consecutive patients, from 2011 to 2013, with biliary complications after LT, documented by PTC. According to US biliary dilation, patients were classified as: mild, moderate, and severe, and according to laboratory findings as: normal or abnormal serum bilirubin and level of serum GGT. Data were correlated with PTC findings, divided in three groups: mild, moderate, and severe/occlusive BDS. There was no statistically significant correlation between the US findings and the laboratory findings and between US findings with PTC. There was a statistically significant correlation between GGT and cholangiography. In our series, abnormal US could not predict the severity of BDS on PTC. Bilirubin results were not able to predict the US findings either. GGT results demonstrated a statistically significant correlation with the severity of BDS found on PTC. These findings emphasize the role of GGT in the evaluation and decision of biliary interventions in pediatric liver transplant recipients.

Risk factors for early and late biliary complications in pediatric liver transplantation

BC are a common source of morbidity after pediatric LT. Knowledge about risk factors may help to reduce their incidence. Retrospective analysis of BC in 116 pediatric patients (123 LT) (single institution, 05/1990-12/2011, medium follow-up 7.9 yr). One-, five-, and 10-yr survival was 91.1%, no patient died of BC. Prevalence and risk factors for anastomotic and intrahepatic BC were examined. There were 29 BC in 123 LT (23.6%), with three main categories: 10 (8.1%) primary anastomotic strictures, eight (6.5%) anastomotic leaks, and three (2.4%) intrahepatic strictures. Significant risk factors for anastomotic leaks were total operation time (increase 1.26-fold) and early HAT (<30 days post-LT; increase 5.87-fold). Risk factor for primary anastomotic stricture was duct-to-duct choledochal anastomosis (increase 5.96-fold when compared to biliary-enteric anastomosis). Risk factors for intrahepatic strictures were donor age >48 yr (increase 1.09-fold) and MELD score >30 (increase 1.2-fold). To avoid morbidity from anastomotic BC in pediatric LT, the preferred biliary anastomosis appears to be biliary-enteric. Operation time should be kept to a minimum, and HAT must by all means be prevented. Children with a high MELD score or receiving livers from older donors are at increased risk for intrahepatic strictures.

The role of interventional radiology in the treatment of biliary strictures after paediatric liver transplantation

PURPOSE

The aim of this study is to evaluate the safety and efficacy of percutaneous treatment of biliary strictures after paediatric liver transplantation.

MATERIALS AND METHODS

In the period between October 1999 and October 2010, a total of 92 transplants in 86 children were performed at our Liver Transplant Centre. Eighteen patients had anastomotic biliary strictures (in four cases associated with intrahepatic bile duct stenosis). Percutaneous treatment (transhepatic biliary drainage and conventional/cutting balloon dilatation) was proposed as a first approach in 13/18 patients. Strict radiation protection precautions were taken in accordance with the ALARA (as low as reasonably achievable) principle. Mean follow-up time was 2,364 days.

RESULTS

Surgical correction was required in 3/13 patients; in 8/13 cases, there was complete disappearance of clinical symptoms without bile duct dilatation; in one case, an asymptomatic persistent bile duct dilatation was detected while in the other case, the liver is currently in cirrhotic degeneration (69 % clinical success including the asymptomatic patient with biliary dilatation). Two of the five patients who were initially treated with surgery required percutaneous revision (clinical success of 100 %). There were two cases of long-term restenosis and two cases of transient haemobilia.

CONCLUSIONS

Percutaneous procedures are safe and effective therapeutic options for the treatment of biliary strictures after paediatric liver transplantation.

Imaging of vascular complications and their consequences following transplantation in the abdomen

Transplantation is the surgical treatment of choice for end-stage organ failure. Transplantation procedures performed in the abdomen include liver, renal, pancreas, islet, intestinal, and multivisceral transplantations. Imaging plays a pivotal role in the posttransplantation setting for monitoring the transplant allograft and screening for complications. Knowledge of the surgical techniques employed in abdominal transplantation is essential because it facilitates radiologic understanding and interpretation of the posttransplantation anatomy. This article includes a basic description of the standard surgical techniques performed in the abdomen, with emphasis on the relevant vascular anastomotic reconstructions used. Posttransplantation complications can be broadly classified as vascular or nonvascular in origin. Many of these complications can be accurately depicted and characterized at imaging and dealt with definitively by using interventional radiology techniques, which can be graft- and life-saving and can obviate further complex surgical intervention. The article discusses imaging appearances of vascular complications and their consequences after transplantation in the abdomen. These vascular complications include arterial thrombosis, arterial stenosis, venous thrombosis and stenosis, arteriovenous fistula formation, and pseudoaneurysm formation. The relevant predisposing factors, clinical features, imaging appearances, and potential treatment options for vascular complications of various types of transplantation are presented in a logical and integrated fashion. Knowledge and imaging recognition of the posttransplantation vascular complications discussed in this article will aid radiologists in accurate imaging characterization and thereby facilitate appropriate clinical management and therapy.

Minimally invasive endovascular and biliary treatments of children with acute hepatic artery thrombosis following liver transplantation

Hepatic artery thrombosis is a major problem after pediatric liver transplantation. Ischemia caused by hepatic artery thrombosis results in severe biliary and parenchymal damage and is associated with high rates of graft loss and mortality. We present a case-based pictorial essay to illustrate the role of minimally invasive treatment in the prompt management of acute hepatic artery thrombosis, and the associated biliary complications.

Radiologic assessment of hepatobiliary surgical complications

The complexity of hepatobiliary procedures continues to evolve at a rapid rate, with an increasing number of living donor liver transplants and extensive cancer resections being performed. The associated complications are a significant cause of morbidity and mortality, and are often complex injuries, involving both vascular and biliary structures. In this paper we describe the complications associated with laparoscopic cholecystectomy, liver transplant surgery, and hepatic resection. Focus is on the classical imaging appearances, imaging modality options, and varying management strategies for these injuries, to show how the radiologist's role is vital in ensuring the correct diagnosis is made and the appropriate treatment is instigated.

Orthotopic liver transplantation: reversible Doppler US findings in the immediate postoperative period

Orthotopic liver transplantation (OLT) is the only definitive treatment for irreversible acute liver failure and chronic liver disease. In the immediate postoperative period after OLT, patients are closely monitored with Doppler ultrasonography (US) to detect treatable vascular complications and ensure graft survival. The first postoperative Doppler US examination is performed fairly early on the first postoperative day, before surgical wound closure has been performed. The immediate postoperative images, obtained when the effects of surgery are very recent, often reveal an array of findings that may appear alarming but that tend to normalize within a few days and are compatible with changes related to the surgery itself. These findings include a starry-sky appearance of reperfusion hepatic edema, transient foci of increased echogenicity, pneumobilia, small fluid collections, perihepatic hematomas, pleural effusion, temporary elevation of hepatic arterial velocity, transient elevation of resistive index (RI), decreased RI with tardus parvus waveform, increased portal venous flow and mono- or biphasic waveforms of the hepatic veins. Most of these changes revert to normal in the first postoperative week; deterioration atypical of transient changes requires further evaluation.

Pre- and postoperative imaging and interventions for the meso-Rex bypass in children and young adults

The meso-Rex bypass is a physiological and anatomical bypass procedure for relief of extrahepatic portal vein obstruction and restoration of mesenteric venous return to the liver. Most patients who are candidates for the bypass are children or young adults with portal hypertension and hypersplenism secondary to cavernous transformation of the portal vein. Most frequently, the bypass utilizes an autologous venous graft to connect the intrahepatic left portal vein to the infrapancreatic superior mesenteric vein (SMV) re-establishing first-pass portal perfusion. We describe the preoperative imaging of the 92 bypass candidates, the surgical anatomy as reflected in postoperative imaging, and the imaging of bypass complications at our institution.Preoperative imaging with US, CT and MR is directed to demonstrate patency and size of the left portal vein and SMV, to define the extent of cavernous transformation and splanchnic collaterals, and to assess for any associated abdominal vascular or solid organ abnormalities. Postoperative imaging is aimed at diagnosing meso-Rex bypass stenosis or occlusion and the interventional management of these complications.

Outcomes of patients with benign liver diseases undergoing living donor versus deceased donor liver transplantation

BACKGROUND/AIMS

The number of people undergoing living donor liver transplantation (LDLT) has increased rapidly in many transplant centres. Patients considering LDLT need to know whether LDLT is riskier than deceased donor liver transplantation (DDLT). The aim of this study was to compare the outcomes of patients undergoing LDLT versus DDLT.

METHODS

A total of 349 patients with benign liver diseases were recruited from 2005 to 2011 for this study. LDLT was performed in 128 patients, and DDLT was performed in 221 patients. Pre- and intra-operative variables for the two groups were compared. Statistically analysed post-operative outcomes include the postoperative incidence of complication, biliary and vascular complication, hepatitis B virus (HBV) recurrence, long-term survival rate and outcomes of emergency transplantation.

RESULTS

The waiting times were 22.10±15.31 days for the patients undergoing LDLT versus 35.81±29.18 days for the patients undergoing DDLT. The cold ischemia time (CIT) was 119.34±19.75 minutes for the LDLT group and 346±154.18 for DDLT group. LDLT group had higher intraoperative blood loss, but red blood cell (RBC) transfusion was not different. Similar ≥ Clavien III complications, vascular complications, hepatitis B virus (HBV) recurrence and long-term survival rates were noted. LDLT patients suffered a higher incidence of biliary complications in the early postoperative days. However, during the long-term follow-up period, biliary complication rates were similar between the two groups. The long-term survival rate of patients undergoing emergency transplantation was lower than of patients undergoing elective transplantation. However, no significant difference was observed between emergency LDLT and emergency DDLT.

CONCLUSIONS

Patients undergoing LDLT achieved similar outcomes to patients undergoing DDLT. Although LDLT patients may suffer a higher incidence of early biliary complications, the total biliary complication rate was similar during the long-term follow-up period.

Multimodality imaging of normal hepatic transplant vasculature and graft vascular complications

Orthotopic liver transplantation is an important treatment option for patients with end-stage liver disease. Advances in surgical technique, along with improvements in organ preservation and immunosuppression have improved patient outcomes. Post-operative complications, however, can limit this success. Ultrasound is the primary imaging modality for evaluation of hepatic transplants, providing real-time information about vascular flow in the graft. Graft vascular complications are not uncommon, and their prompt recognition is crucial to allow for timely graft salvage. A multimodality approach including CT angiography, MRI, or conventional angiography may be necessary in cases of complex transplant vascular anatomy or when sonography and Doppler are inconclusive to diagnose the etiologies of these complications. The purpose of this article is to familiarize radiologists with the normal post-transplant vascular anatomy and the imaging appearances of the major vascular complications that may occur within the hepatic artery, portal vein, and venous outflow tract, with an emphasis on ultrasound.

Transcapsular arterial neovascularization after liver transplantation in pediatric patients indicates transplant failure

PURPOSE

To identify transcapsular arterial neovascularization with Doppler ultrasonography (US) in pediatric patients after liver transplantation and to assess the frequency of the finding, its underlying causes, and its relevance in terms of clinical outcome.

MATERIALS AND METHODS

The study was approved by the local ethics committee, with waived informed consent. All pediatric patients who underwent liver transplantation between January 2000 and December 2003 were retrospectively evaluated. Patients were followed up until June 2008, by using a predefined US protocol with prospective documentation. Of 182 consecutive liver transplantations performed in 162 patients (mean age, 4.5 years; range, 0.1-18.4 years) in this period, 25 patients with a total of 27 liver transplantations underwent US examinations conducted by multiple investigators and were primarily excluded. Student t tests and χ(2) tests were performed where appropriate. The Tarone-Ware test was used to compare transplant survival times.

RESULTS

Transcapsular arterial neovascularization was noticed in 13 of 137 patients (9.5%) and in 13 of 155 liver transplants (8.4%). The mean time until arterial neovessels appeared was 157 days after liver transplantation (median, 97 days; range, 19-477 days). Arterial neovascularization was associated with pronounced transplant malperfusion and inflammatory changes (P < .001). Patients with transcapsular arterial neovascularization had a significantly shorter mean transplant survival time (1426.4 days ± 244.5 [standard error], with 95% confidence interval: 947.23, 1905.23, vs 2526.4 days ± 92.1, with 95% confidence interval: 2345.84, 2706.97; P = .008) and a higher retransplantation rate (53.8% vs 19.7%, P = .009).

CONCLUSION

Transcapsular arterial neovascularization, detected with color Doppler US, occurred in 9.5% (13 of 137) of pediatric patients and 8.4% (13 of 155) of liver transplants and was associated with underlying malperfusion and inflammation. The diagnosis of transcapsular arterial neovascularization was associated with reduced graft survival times and a high retransplantation rate. The negative prognostic value of the sign may assist in a strategy of organ allocation.

Liver transplantation in children using organs from young paediatric donors

Nowadays, most paediatric liver transplant recipients receive a split or other technical variant graft from adult deceased or live donors, because of a lack of available age- and size matched paediatric donors. Few data are available, especially for liver grafts obtained from very young children (<6 years). We analysed all paediatric liver transplantations between 1989 and 2009. Recipients were divided into five groups (1-5) depending on donor age (<1, ≥1 to <6, ≥6 to <16, ≥16 to <45, ≥45 years). Overall, 413 paediatric liver transplantations from deceased donors were performed; 1- and 5-year graft survival rates were 75%, 80%, 78%, 81%, 74% and 75%, 64%, 70%, 67%, 46%, and 1- and 5-year patient survival rates were 88%, 91%, 90%, 89%, 78% and 88%, 84%, 84%, 83%, 63% for groups 1-5, respectively, without significant difference. Eight children received organs from donors younger than 1 year and 45 children received organs from donors between 1 and 6 years of age. Overall, vascular complications occurred in 13.2% of patients receiving organs from donors younger than 6 years. Analysis of our data revealed that the usage of liver grafts from donors younger than 6 years is a safe procedure. The outcome was comparable with grafts from older donors with excellent graft and patient survival, even for donors younger than 1 year.

Imaging of biliary disorders in children

Biliary atresia and related disorders of the biliary tree, such as choledochal cyst, must be considered in the differential diagnosis of prolonged conjugated hyperbilirubinemia in infants and children. Pediatric biliary tract diseases include a variety of entities with a wide range of clinical presentations. Radiology plays an important role in the diagnosis and management of these pathologies. Unrecognized causes of biliary disease, like biliary atresia, can lead to liver transplantation during the first year of life. The aim of this article is to review the imaging of pediatric biliary disorders, including the implications of interventional radiology in some biliary diseases.

Deep hypothermia with circulatory arrest to aid in the management of suprahepatic vena cava stenosis after liver transplantation

Liver transplantation is the treatment of choice for many liver diseases in the pediatric population. Complications involving late suprahepatic vena cava obstructions after liver transplantation are not common, but they tend to be more frequently seen in pediatric recipients. When such complications have occurred, approaches involving direct abdominal surgery or interventional radiology guidance have been used with satisfactory results. We present a case report of an alternative approach to a suprahepatic vena cava complication. An 18-year-old man who underwent pediatric liver transplantation for biliary atresia presented with a symptomatic total occlusion of the suprahepatic caval anastomosis that could not be crossed with a wire. We used a right atrial approach and hypothermic circulatory (cardiac) arrest. The anastomotic stricture was easily identified and excised. The postoperative course was uneventful with a rapid resolution of the symptoms. Because the occlusion was not amenable to angioplasty or stenting, a direct surgical approach was necessary. The right atrial approach with hypothermic cardiac arrest gave us direct access to the obliterated cavoatrial anastomosis through a virgin area and allowed us to avoid the difficulties and dangers of the large collaterals in the abdomen.

Imaging of the transplant liver

As the number of patients with liver transplants continues to increase, radiologists need to be aware of the normal post-operative appearance of the different liver transplants currently performed along with the wide variety of complications encountered. The complications commonly affect the biliar and vascular systems and can include anastomotic bile leakage and biliary stenosis along with stenosis or obstruction of the hepatic artery, portal or hepatic veins and IVC. Other complications include parenchymal abnormalities such as hepatic infarction, organ rejection, localized collections and post transplant lymphoproliferative disorder. This article reviews and illustrates the role of imaging for pediatric transplantation including the role of interventional radiology.