Risk factors of hepatic artery thrombosis in pediatric deceased donor liver transplantation

Paediatric acute liver failure: a multidisciplinary perspective on when a critically ill child is unsuitable for liver transplantation

Paediatric acute liver failure is a devastating condition with high morbidity and mortality, which is challenging to manage for the hepatologist, intensivist, and associated specialists. Emergency liver transplantation is required for 10-20% of patients, but for 10% of critically ill children, liver transplantation is deemed unsuitable; the child might be too unwell, or the underlying cause might carry a poor prognosis. Other social, logistical, or ethical considerations are often relevant. Liver transplantation when a patient is too unwell creates perioperative risk to the child that could lead to morbidity, mortality, and potential graft wastage, which is detrimental for others on the waiting list. Donor liver scarcity should prompt an evaluation of whether a transplant is justified through a holistic multidisciplinary lens that considers medical, social, logistical, and ethical concerns. In this Review, we explore, from a multidisciplinary perspective, why a critically unwell child with paediatric acute liver failure might be unsuitable for liver transplantation.

Treatment strategies for hepatic artery complications after pediatric liver transplantation: A systematic review

This study aimed to evaluate the effectiveness of different treatments for hepatic artery thrombosis (HAT) and hepatic artery stenosis (HAS) after pediatric liver transplantation. We systematically reviewed studies published since 2000 that investigated the management of HAT and/or HAS after pediatric liver transplantation. Studies with a minimum of 5 patients in one of the treatment methods were included. The primary outcomes were technical success rate and graft and patient survival. The secondary outcomes were hepatic artery patency, complications, and incidence of HAT and HAS. Of 3570 studies, we included 19 studies with 328 patients. The incidence was 6.2% for HAT and 4.1% for HAS. Patients with an early HAT treated with surgical revascularization had a median graft survival of 45.7% (interquartile range, 30.7%-60%) and a patient survival of 61.3% (interquartile range, 58.7%-66.9%) compared with the other treatments (conservative, endovascular revascularization, or retransplantation). As for HAS, endovascular and surgical revascularization groups had a patient survival of 85.7% and 100% (interquartile range, 85%-100%), respectively. Despite various treatment methods, HAT after pediatric liver transplantation remains a significant issue that has profound effects on the patient and graft survival. Current evidence is insufficient to determine the most effective treatment for preventing graft failure.

The effect of an organ procurement organization surgeon on pediatric organ utilization

INTRODUCTION

Organ procurement organizations (OPO) have started to employ transplant-trained surgeons dedicated to organ procurement with the aim to increase allograft utilization and enhance the use of procured organs. We investigated the effects of an OPO-employed surgeon on the procurement and utilization of organs from pediatric donors within the Southwestern Transplant Alliance OPO.

METHODS

OPO data were obtained for all procurements that were performed between 2014 and 2019. The analysis was performed to see if the presence of an OPO donor surgeon impacted the utilization of pediatric livers. Donor and recipient demographic data were examined between allografts procured with the presence of an OPO surgeon (OPO-Present) and those without an OPO surgeon (OPO-Absent). A p-value of <.05 was considered significant.

RESULTS

Of 149 pediatric procurements, 91 included an OPO-donor surgeon. In procurements with OPO-Present, donors were younger (8.2 vs. 11.2, p < .05) and had longer distances to travel to the recipient center (334 vs. 175 miles p < .05), but had comparable cold ischemic times. In terms of organ share type, more OPO-Present livers were shared nationally and there was no difference in discard rate between OPO-Present and OPO-Absent procurements. Finally, OPO-Present livers were more likely to be transplanted to pediatric recipients compared to OPO-Absent (47.3% vs. 24.1% p < .05).

CONCLUSION

The presence of an OPO surgeon has impacted organ utilization, leading to increased transplantation of pediatric livers in pediatric recipients, and has expanded the geographical share of pediatric livers.

Vascular thrombosis after pediatric liver transplantation: Is prevention achievable?

Background

Vascular thromboses (VT) are life-threatening events after pediatric liver transplantation (LT). Single-center studies have identified risk factors for intra-abdominal VT, but large-scale pediatric studies are lacking.

Methods

This multicenter retrospective cohort study of isolated pediatric LT recipients assessed pre- and perioperative variables to determine VT risk factors and anticoagulation-associated bleeding complications.

Results

Within seven postoperative days, 31/331 (9.37%) patients developed intra-abdominal VT. Open fascia occurred more commonly in patients with VT (51.61 vs 23.33%) and remained the only independent risk factor in multivariable analysis (OR = 2.84, p = 0.012). Patients with VT received more blood products (83.87 vs 50.00%), had significantly higher rates of graft loss (22.58 vs 1.33%), infection (50.00 vs 20.60%), and unplanned return to the operating room (70.97 vs 16.44%) compared to those without VT. The risk of bleeding was similar (p = 0.2) between patients on and off anticoagulation.

Conclusions

Prophylactic anticoagulation did not increase bleeding complications in this cohort. The only independent factor associated with VT was open fascia, likely a graft/recipient size mismatch surrogate, supporting the need to improve surgical techniques to prevent VT that may not be modifiable with anticoagulation.

Potential of neonatal organ donation and outcome after transplantation

Organ transplantation is limited by access to suitable organs. Infant recipient waitlist mortality is increased due to the scarcity of size-matched organs. Neonatal organ donors have been proposed as an underutilized source of donor organs. However, the literature on the actual prevalence and outcome of neonatal organ donation and transplantation is fragmented and not well analyzed. This literature review aims to summarize the available literature on the potential of neonatal organ donation and to analyze published cases of neonatal organ transplantation. A systematic search of the Medline and Cochrane databases yielded 2964 articles, which were screened for eligibility. In total, 86 articles were considered eligible, of which 34 were included in the literature review: 8 articles describing the potential of neonatal organ donation programs, and 26 articles describing clinical transplantation. Current evidence suggests there is a large pool of potential neonatal organ donors. In contrast, the literature on neonatal organ donor utilization is sparse. However, case series of successful kidney, heart, liver, hepatocyte, and multivisceral transplantation using organs from neonatal donors are summarized. Although good posttransplant organ function was achieved, the use of neonatal organs is associated with increased risk of thrombosis in both kidney and liver transplantation. Neonatal organ donation is a promising alternative for expanding the current donor pool. Experience is limited, but reported patient and graft survival are acceptable and more research on the subject is warranted.

Impact of donor age on short-term outcomes after pediatric split liver transplantation

Background

Donor shortage is an important limitation of liver transplantation (LT). Split liver transplantation (SLT) may increase the sources of donors and reduce the problem of organ shortage. However, there are no standard criteria of the selection of SLT donor, especially regarding the donor age.

Methods

We retrospectively analyzed the clinical data of children who received initial SLT between January 2015 and December 2021. Based on the age of donors, the patients were divided into groups A (1-10 years old; n = 26), B (10-45 years old; n = 87), and C (45-55 years old; n = 27). The short-term (<1 year after SLT) outcomes of the recipients were analyzed.

Results

A total of 140 patients received SLT from 122 donors. The 1-, 3- and 12-month patient survival rates in group A were 100.0%, and the graft survival rates were 92.3%. The 1-, 3- and 12-month survival rates of patient and graft in group B were 97.7%, 96.6%, and 95.0%, respectively, and in group C were 85.2%, 85.2%, and 81.1%, respectively. The patient survival rate was significantly lower in group C than in groups A and B (p = 0.0082). There was no significant difference in graft survival between the three groups (p = 0.0545).

Conclusions

Similar results were obtained for pediatric SLT with donors <10 years old and 10-45 years old. Pediatric SLT can be performed with older donors (45-55 years) after strict donor selection and selection of appropriate recipients.

Microsurgical replacement of the right hepatic artery with the donor superior mesenteric artery in cadaveric donor pediatric liver transplantation

PURPOSE

To present our experience of using the pediatric donor superior mesenteric artery (SMA) as the interpositioning vessel to reconstruct the hepatic artery in pediatric deceased donor liver transplantation.

METHODS

Pediatric patients who received pediatric deceased donor livers from December 2019 to June 2021 were enrolled.

RESULTS

A total of 43 pediatric recipients received pediatric deceased donor livers during the study period. Thirty-four (79.1%) pediatric donors had normal hepatic artery anatomy, while nine (20.9%) showed variant anatomies. The SMAs of the pediatric donors were interposed in the latter eight cases. The anastomosis between the donor distal SMA and the donor celiac trunk artery (CTA) was initially performed in the back-table period, after which the other anastomosis between the donor proximal SMA and recipient CHA was performed. Only one case showed HAT occurrence (incidence rate, 2.3%). However, no arterial complications occurred in pediatric recipients with donor grafts that showed the variation of RHA replacement from the SMA and had undergone usage of the donor's SMA as an interpositioning vessel.

CONCLUSIONS

In pediatric deceased donor liver transplantation, the use of SMA as an interpositioning medium can solve the problems related to a tiny caliber and anatomical variations of the donor hepatic artery.

Management and outcome of hepatic artery thrombosis with whole-liver transplantation using donors less than one year of age

BACKGROUND/PURPOSE

The incidence of hepatic artery thrombosis (HAT) in recipients is high after pediatric LT using young donors. In this study we investigated the management and outcome of HAT after whole-LT using donors less than one year of age. And evaluate the safety of pediatric donors, and increase the utilization of pediatric donors overall.

METHODS

We retrospectively analyzed the clinical data encompassing children who underwent whole-liver transplantation in our department from January 2014 to December 2019. Recipients receiving a liver from a donor ≥1 month and ≤12 months were included, and a total of 110 patients were included in this study.

RESULTS

The results showed an incidence for HAT of 20% and the median time to HAT diagnosis was 3.0 (2.0, 5.3) days post-operation. Anticoagulant therapy was used for 19 cases and 94.7% of them achieved hepatic artery recanalization or collateral formation. The median time of recanalization was 12 (5, 15) days. Bile leakage and biliary strictures occurring in the HAT group were higher than in the non HAT group (13.6% vs. 1.1% and 31.8% vs. 3.4%). There were no significant differences in the survival rates of recipients or grafts among the two groups (P = 0.474, P = 0.208, respectively).

CONCLUSION

We confirmed that the incidence of HAT in LT recipients use donors less than 1 year is high, but recanalization can be performed using anticoagulant therapy. Although biliary complications increased significantly after HAT, the survival rates of patients and grafts were satisfactory.

LEVEL OF EVIDENCE

Level III.

Our evolution in the treatment of hepatic artery and portal vein thrombosis in pediatric liver transplantation: Success with catheter-directed therapies

BACKGROUND

In pediatric liver transplant recipients, hepatic artery thrombosis and portal vein thrombosis are major causes of acute graft failure and mortality within 30 days of transplantation. There is, however, a strong possibility of graft salvage if flow can be re-established to reduce ischemic injury. The current standard treatment is surgical revascularization, and if unsuccessful, retransplantation. Due to our success in treating these complications with catheter-directed therapies, we sought to summarize and publish the outcomes of all patients who experienced hepatic artery thrombosis or portal vein thrombosis within 30 days of liver transplantation.

METHODS

We conducted a retrospective cohort analysis of 27 pediatric liver transplant recipients who experienced hepatic artery thrombosis (n = 13), portal vein thrombosis (n = 9), or both (n = 5) between September 2012 and March 2021. We collected and tabulated data on the patients and therapies performed to treat them, including success rates, primary and secondary patency, and clinical outcomes.

RESULTS

Among these patients, 6 were managed with anticoagulation and relisting for transplant and 21 had a primary revascularization attempt. Surgical recanalization was attempted in 7 patients of which 3 had successful recanalization (43%) and catheter-directed recanalization was attempted in 14 patients with 100% success in re-establishing blood flow to the graft. Additionally, patency was increased, and mortality was decreased in patients treated with catheter-directed recanalization compared to surgical revascularization or anticoagulation alone.

CONCLUSION

This data illustrates the need to further investigate catheter-directed thrombolysis as a potential first-line treatment for postoperative HAT and PVT in pediatric liver transplant recipients.

Outflow reconstruction of left lateral graft with two widely spaced hepatic veins in pediatric living donor liver transplantation

BACKGROUND

Living donor liver transplantation using the left lateral segment of the liver is the most common type of pediatric liver transplantation. An appropriate surgical approach is crucial for decreasing the risk of vascular complications using these grafts with anatomical variations.

METHODS

Between January 2017 and December 2020, 631 living donor liver transplantations using left lateral segment grafts were performed at Tianjin First Central Hospital. The grafts from 162 (25.7%) donors have 2 hepatic vein openings. A total number of 21 transplantations using left lateral segment grafts with 2 widely spaced hepatic vein openings were performed. In group 1, the unification venoplasty technique with interposition vein graft was used at the back table for the reconstruction of hepatic vein from grafts. In group 2, dual hepatic vein reconstructions were performed, in which venoplasty of recipients' left hepatic vein, middle hepatic vein, and inferior vena cava was performed to create a large orifice for anastomosis with segment Ⅱ hepatic vein from the graft. Segment III hepatic vein from the graft was anastomosed with the recipient's right hepatic vein. The incidence, treatment, and outcomes of hepatic venous outflow obstruction were compared between the 2 groups.

RESULTS

The median follow-up time was 12.8 months. There was no significant difference in the incidence of hepatic venous outflow obstruction between the 2 groups.

CONCLUSION

Dual hepatic vein reconstruction is an alternate surgical option for grafts with 2 widely spaced hepatic veins, and it is associated with ideal graft recovery and vascular condition. However, long-term follow-up is still needed to verify the efficacy and safety of this approach.

Risk Factors Affecting Outcomes in Pediatric Liver Transplantation: A Real-World Single-Center Experience

Background

Despite liver transplantation (LT) being the standard treatment for pediatric end-stage liver disease, complications often persist and can adversely affect the post-transplant outcomes. This study aimed to identify the risk factors affecting the outcomes in pediatric LT patients.

Material/Methods

Data from pediatric patients who underwent primary LT from March 1988 to December 2018 were retrospectively analyzed. Chronic liver disease was defined as an explanted liver showing fibrosis regardless of grade, cirrhosis, or any other underlying disease that may cause progressive liver injury leading to fibrosis or cirrhosis.

Results

A total of 255 pediatric patients underwent LT during the study period. Their 1-, 5-, and 10-year overall survival rates were 90.5%, 88.4%, and 87.8%, respectively. According to multivariate analysis, while liver disease without underlying chronic liver disease (P=0.024) and a pediatric end-stage liver disease (PELD) score ≥30 (P=0.036) were the only factors associated with worse survival, body weight <6 kg (P=0.050), whole-liver DDLT compared to LDLT (P=0.001), fulminant liver failure (P=0.008), and postoperative hepatic artery complications (P<0.001) were associated with worse graft survival. Liver disease without underlying chronic liver disease was the only factor independently associated with hepatic artery complications (P=0.003).

Conclusions

Greater caution is recommended in pediatric patients with liver disease unaccompanied by underlying chronic liver disease, high PELD score, or low body weight to improve survival after LT. Hepatic artery complication was the only surgical complication affecting the graft survival outcome, especially in patients having liver disease without underlying chronic liver disease.

The management and outcomes of ABO-incompatible pediatric liver transplantation: Experience of a single Chinese center

BACKGROUND

To investigate the safety of using ABO incompatible (ABO-i) liver grafts in pediatric patients under our prophylactic strategies.

METHODS

A total number of 544 pediatric liver transplantations between January 2013 and December 2017 performed in Organ Transplant Center, Tianjin First Central Hospital were included in this study. The recipients were divided into 3 groups based on the compatibility of donor-recipient blood type matching (ABO-identical group, n = 352, ABO-compatible group, n = 121 and ABO-incompatible group, n = 71). Recipient characteristics, perioperative data, postoperative complications and recipient survival rate were compared. The recipient outcomes between living-related and non-living-related ABO-incompatible liver graft recipients were also compared.

RESULTS

The median follow-up time in three groups were 3.4 (1.8, 6.4) years, 3.2 (1.8, 6.1) years and 2.8 (1.8, 6.2) years, without statistical difference. The cumulative 1-year and 3-year graft survival rate were 94.3% and 94.0% in ABO-id group, 93.1% and 93.1% in ABO-c group and 97.1% and 97.1% in ABO-i group. The cumulative 1-year and 3-year recipient survival rate were 96.1% and 95.5% in ABO-id group, 94.8% and 94.8% in ABO-c group and 97.1% and 97.1% in ABO-i group, respectively. No significant difference was seen among three groups. The recipient characteristics and perioperative data were similar among three groups. The recipients in ABO-i group showed significantly lower incidence of portal vein stenosis. Apart from that, three groups shared equal incidence of other surgical complications and acute rejection. Among ABO-i liver graft recipients, the cumulative 1-year and 3-year recipient survival rate were 98.2% and 98.2% in living donor liver transplant (LDLT) recipients and 92.9% and 92.9% in deceased donor liver transplant (DDLT) recipients, without significant difference. The incidence of hepatic artery thrombosis was significantly higher in DDLT group compared with LDLT group, while the other complications were similar between two groups.

CONCLUSION

Our data revealed that the application of ABO-i liver grafts in pediatric liver transplantation under rational peri-operative management strategy is a safe measure to increase donor availability for pediatric patients in Chinese population.

LEVELS OF EVIDENCE

III.

Additional value of superb microvascular imaging for assessing hepatic arterial blood flow after pediatric liver transplantation

BACKGROUND

The aim of this study was to explore the value of SMI compared with conventional ultrasonography for assessing hepatic arterial blood flow after pediatric liver transplantation.

METHODS

From March 2018 to November 2018, a total of 105 pediatric recipients with biliary atresia underwent liver transplantation in our hospital. Ultrasound examinations were performed at the bedside in the intensive care unit to check the patency of the blood flow in the hepatic allograft. CDI, PDI, cSMI, and mSMI were performed to assess the display, orientation, and distribution of the graft hepatic artery. Ultrasound examinations were performed by one radiologist, and the images were judged by two observers.

RESULTS

The median age, weight, and height of the recipients were 6.97 (5.92, 9.58) months, 6.50 (6.00, 7.80) kg, and 64.00 (62.00, 68.00) cm, respectively. The measure of kappa agreement was 0.902, 0.889, 0.882, and 0.882 for CDI, PDI, cSMI, and mSMI, respectively. HAT occurred in 7 pediatric recipients and was confirmed by CTA (computed tomography angiography) and surgery. The diagnostic performance of sensitivity, specificity, PPV (positive predictive value), NPV (negative predictive value), and accuracy were 100%, 92.86%, 50%, 100%, and 93.33% for CDI and 100%, 98.98%, 87.50%, 100%, and 99.05% for SMI.

CONCLUSIONS

As an additional method to CDI, SMI can clearly show the distribution of hepatic arterial blood flow and provide more details, thereby markedly improving the diagnostic performance of postoperative HAT.

Hepatic artery reconstruction in pediatric liver transplantation: Experience from a single group

BACKGROUND

The reconstruction of hepatic artery is a challenging part of the pediatric liver transplantation procedure. Hepatic artery thrombosis (HAT) and stenosis are complications which may result in ischemic biliary injury, causing early graft lost and even death.

METHODS

Two hundred and fifty-nine patients underwent liver transplantation in 2017 in a single liver transplantation group. Among them, 225 patients were living donor liver transplantation (LDLT) and 34 deceased donor liver transplantation (DDLT).

RESULTS

In LDLT all reconstructions of hepatic artery were microsurgical, while in DDLT either microsurgical reconstruction or traditional continuous suture technique was done depending on different conditions. There were five (1.9%) HATs: four (4/34, 11.8%) in DDLT (all whole liver grafts) and one (1/225, 0.4%) in LDLT (P = 0.001). Four HATs were managed conservatively using anticoagulation, and 1 accepted salvage surgery with re-anastomosis. Until now, 3 HAT patients remain in good condition, whereas two developed biliary complications. One of them needed to be re-transplanted, and the other patient died due to biliary complications.

CONCLUSIONS

Microsurgical technique significantly improves the reconstruction of hepatic artery in pediatric liver transplantation. The risk for arterial complications is higher in DDLT. Conservative therapy can achieve good outcome in selected HAT cases.

Post-transplantation Outcomes in Patients with PA or MMA: A Review of the Literature

Introduction

Liver transplantation is recognised as a treatment option for patients with propionic acidemia (PA) and those with methylmalonic acidemia (MMA) without renal impairment. In patients with MMA and moderate-to-severe renal impairment, combined liver–kidney transplantation is indicated. However, clinical experience of these transplantation options in patients with PA and MMA remains limited and fragmented. We undertook an overview of post-transplantation outcomes in patients with PA and MMA using the current available evidence.

Methods

A literature search identified publications on the use of transplantation in patients with PA and MMA. Publications were considered if they presented adequate demographic and outcome data from patients with PA or MMA. Publications that did not report any specific outcomes for patients or provided insufficient data were excluded.

Results

Seventy publications were identified of which 38 were full papers. A total of 373 patients underwent liver/kidney/combined liver–kidney transplantation for PA or MMA. The most typical reason for transplantation was recurrent metabolic decompensation. A total of 27 post-transplant deaths were reported in patients with PA [14.0% (27/194)]. For patients with MMA, 18 post-transplant deaths were reported [11% (18/167)]. A total of 62 complications were reported in 115 patients with PA (54%) with cardiomyopathy (n = 12), hepatic arterial thrombosis (HAT; n = 14) and viral infections (n = 12) being the most commonly reported. A total of 52 complications were reported in 106 patients with MMA (49%) with viral infections (n = 14) and renal failure/impairment (n = 10) being the most commonly reported.

Conclusions

Liver transplantation and combined liver–kidney transplantation appears to benefit some patients with PA or MMA, respectively, but this approach does not provide complete correction of the metabolic defect and some patients remain at risk from disease-related and transplantation-related complications, including death. Thus, all treatment avenues should be exhausted before consideration of organ transplantation and the benefits of this approach must be weighed against the risk of perioperative complications on an individual basis.

Application of pediatric donors in split liver transplantation: Is there an age limit?

The experience of using pediatric donors in split liver transplant is exceedingly rare. We aim to investigate the outcomes of recipients receiving split pediatric grafts. Sixteen pediatric recipients receiving split liver grafts from 8 pediatric donors < 7 years were enrolled. The donor and recipient characteristics, perioperative course, postoperative complications, and graft and recipient survival rates were evaluated. The mean follow-up time was 8.0 ± 2.3 months. The graft and recipient survival rates were 100%. The liver function remained in the normal range at the end of the follow-up time in all recipients. No life-threatening complications were seen in these recipients, and the only surgery-related complication was portal vein stenosis in 1 recipient. Cytomegalovirus infection was the most common complication (62.5%). The transaminase level was significant higher in extended right lobe recipients in the early postoperative days, but the difference vanished at the end of first week; postoperative complications and graft and recipient survival rates did not differ between left and right graft recipients. Notably, the youngest split donor graft (2.7 years old) was associated with ideal recipient outcomes. Split liver transplant using well-selected pediatric donors is a promising strategy to expand pediatric donor source in well-matched recipients.