Perioperative thrombotic complications associated with pediatric liver transplantation: a UNOS database evaluation

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.

Predicting graft failure in pediatric liver transplantation based on early biomarkers using machine learning models

The early detection of graft failure in pediatric liver transplantation is crucial for appropriate intervention. Graft failure is associated with numerous perioperative risk factors. This study aimed to develop an individualized predictive model for 90-days graft failure in pediatric liver transplantation using machine learning methods. We conducted a single-center retrospective cohort study. A total of 87 liver transplantation cases performed in patients aged < 12 years at the Severance Hospital between January 2010 and September 2020 were included as data samples. Preoperative conditions of recipients and donors, intraoperative care, postoperative serial laboratory parameters, and events observed within seven days of surgery were collected as features. A least absolute shrinkage and selection operator (LASSO) -based method was used for feature selection to overcome the high dimensionality and collinearity of variables. Among 146 features, four variables were selected as the resultant features, namely, preoperative hepatic encephalopathy, sodium level at the end of surgery, hepatic artery thrombosis, and total bilirubin level on postoperative day 7. These features were selected from different times and represent distinct clinical aspects. The model with logistic regression demonstrated the best prediction performance among various machine learning methods tested (area under the receiver operating characteristic curve (AUROC) = 0.898 and area under the precision-recall curve (AUPR) = 0.882). The risk scoring system developed based on the logistic regression model showed an AUROC of 0.910 and an AUPR of 0.830. Together, the prediction of graft failure in pediatric liver transplantation using the proposed machine learning model exhibited superior discrimination power and, therefore, can provide valuable information to clinicians for their decision making during the postoperative management of the patients.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

LEVEL OF EVIDENCE

Ⅲ.

Quadratus lumborum blocks for abdominal transplant surgeries at UPMC Children's Hospital of Pittsburgh-A five year experience

BACKGROUND

Adequate perioperative analgesia for pediatric abdominal transplant surgery is essential for patient recovery. However, the risks of commonly used medications such as hepatotoxicity, nephrotoxicity, bleeding concerns, and poor graft results with opioids limit pain management in this population. Thoracic epidural, continuous erector spinae plane, and type-1 quadratus lumborum blocks (QLBs) have been described and utilized in the adult population in this setting. The safety and benefits of regional anesthetic techniques in pediatrics have been widely documented for different types of procedures except pediatric abdominal transplantation, where data remains scarce. Our primary goal was to determine if QLBs provided adequate perioperative analgesia when part of a multimodal approach. Secondary objectives were to examine complications and effects on the intensive care unit (ICU) and hospital stay.

METHODS

We performed a retrospective, observational study of pediatric patients who underwent abdominal transplant surgeries at the University of Pittsburgh Medical Center Children's Hospital of Pittsburgh from January 2015 to July 2021 and received a single injection QLB for pain control. Data collected included: demographics, nerve block characteristics, perioperative opioid consumption, use of non-opioid analgesia, daily pain scores, and hospital and ICU stay.

RESULTS

Forty-two patients met the inclusion criteria for our study. Our results suggest that QLBs decrease opioid consumption, facilitate early extubation, prevent reintubation in the ICU, and reduce ICU and hospital stay.

CONCLUSIONS

QLB is feasible and can be used as a multimodal approach for postoperative pain control in pediatric solid organ transplantation.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

European Liver Transplant Registry: Donor and transplant surgery aspects of 16,641 liver transplantations in children

BACKGROUND AND AIMS

The European Liver Transplant Registry (ELTR) has collected data on liver transplant procedures performed in Europe since 1968.

APPROACH AND RESULTS

Over a 50-year period (1968-2017), clinical and laboratory data were collected from 133 transplant centers and analyzed retrospectively (16,641 liver transplants in 14,515 children). Data were analyzed according to three successive periods (A, before 2000; B, 2000-2009; and C, since 2010), studying donor and graft characteristics and graft outcome. The use of living donors steadily increased from A to C (A, n = 296 [7%]; B, n = 1131 [23%]; and C, n = 1985 [39%]; p = 0.0001). Overall, the 5-year graft survival rate has improved from 65% in group A to 75% in group B (p < 0.0001) and to 79% in group C (B versus C, p < 0.0001). Graft half-life was 31 years, overall; it was 41 years for children who survived the first year after transplant. The late annual graft loss rate in teenagers is higher than that in children aged <12 years and similar to that of young adults. No evidence for accelerated graft loss after age 18 years was found.

CONCLUSIONS

Pediatric liver transplantation has reached a high efficacy as a cure or treatment for severe liver disease in infants and children. Grafts that survived the first year had a half-life similar to standard human half-life. Transplantation before or after puberty may be the pivot-point for lower long-term outcome in children. Further studies are necessary to revisit some old concepts regarding transplant benefit (survival time) for small children, the role of recipient pathophysiology versus graft aging, and risk at transition to adult age.

Management of Acute Portal Vein Thrombosis With Serial Mechanical Thrombectomy and tPA in a Pediatric Liver Transplant Recipient: A Case Report

BACKGROUND

Acute portal vein thrombosis is a major cause of fulminant allograft failure in pediatric liver transplantation. Timely intervention is critical to save the graft and patient. Serial interventional radiologic management of this condition is scarcely reported in the literature.

CASE SUMMARY

A recently transplanted 17-year-old male presented to the emergency department with abdominal pain. Rising liver enzymes prompted discovery of a diffuse portal thrombus, which precipitated fulminant liver failure. The adolescent developed respiratory failure, vasodilatory shock, acute kidney injury, and hepatic encephalopathy, complicating treatment. Multiple interventions attempted to clear the thrombus, including interventional radiologic and medical therapies. Uniquely, a continuous infusion catheter was placed at the thrombosis, delivering local tissue plasminogen activator during a 5-day period. Upon thrombus clearance, the patient made a full recovery with no complications during 12 months of follow-up.

CONCLUSIONS

When used as a component of multidisciplinary management, continuous locally directed tissue plasminogen activator may be a useful tool for clearance of persistent portal vein thrombosis.

Time is of the essence: A single-center experience of hepatic arterial supply impairment management in pediatric liver transplant recipients

BACKGROUND

Impairment of hepatic arterial flow including hepatic arterial thrombosis (HAT), hepatic arterial stenosis (HAS), and splenic artery steal syndrome (SASS) is potentially life-threatening complications. The proposed early diagnosis and urgent treatment strategy of graft arterial flow reduction aim to decrease morbidity and mortality.

METHODS

Pediatric patients with known hepatic arterial flow impairment were retrospectively reviewed. Patients were grouped by occlusive (HAT) and non-occlusive (HAS/SASS) arterial flow reduction. Patients with HAT were further divided in two groups based on the estimated maximal hepatic artery occlusion time ≤8 and >8 hours.

RESULTS

Impairment of hepatic arterial flow developed in 32 of 416 pediatric liver transplant recipients. HAT, HAS, and SASS incidences were 4.1% (n = 17), 2.2% (n = 9), and 1.4% (n = 6), respectively. Neither graft loss nor death occurred in the non-occlusive group. The probabilities of sepsis (OR, 1.7; 95% CI, 1.14-2.53; P=.008) and graft loss or death (OR, 1.42; 95% CI, 1.04-1.92; P=.046) were higher in the occlusive group. Patients with estimated maximal duration of hepatic artery occlusion ≤ 8 hours (n = 7; 41.2%) did not have ischemic-type biliary lesions and sepsis (P=.044 and 0.010, respectively) but had excellent 3-year graft survival compared with > 8 hours group (100% vs 40%; P=.037). Multivariate analysis revealed HAT manifestation by fever was associated with increased chances of graft loss or death.

CONCLUSION

Occlusive arterial complications impose higher risks of graft loss and death. Thorough arterial supply monitoring by Doppler ultrasonography and urgent endovascular arterial flow restoration may salvage both graft and the recipient.

Hyponatremia Is Associated With Increased Mortality in Children on the Waiting List for Liver Transplantation

Our aim was to determine whether hyponatremia is associated with waiting list or posttransplantation mortality in children having liver transplantation (LT).

Hyponatremia Is Protective Against the Development of Portal Vein Thrombosis in Patients Undergoing Liver Transplant

BACKGROUND

Both hyponatremia and portal vein thrombosis (PVT) reflect the severity of liver dysfunction and are independently associated with increased morbidity in cirrhotic patients. In this study, we analyzed effects of hyponatremia on PVT development.

METHODS

Data on adult liver transplants (LTs) in the Model for End-Stage Liver Disease era through September 2016 were obtained. Receiver operating curves and multivariable logistic regression models were constructed to evaluate the association between serum sodium level and PVT. Based on the receiver operating curves, hyponatremia was defined as a sodium level below 125 mEq/L.

RESULTS

Of the 49,155 recipients included, 16% had hyponatremia (n = 7828) and 9% had PVT (n = 4414) at transplant. Subjects with hyponatremia had lower rates of PVT at the time of LT (4.4% vs 10.1%, P < .001), incidence of nonalcoholic steatohepatitis (10.8% vs 16.5%, P < .001), diabetes (19.7% vs 24.3%, P < .001), and need for dialysis (8.8% vs 16.0%, P < .001) as well as higher rates of chronic hepatitis C and B (37.6% vs 29.1%, P < .001 and 2.9% vs 1.7%, P < .001). Multivariable regression analysis confirmed that hyponatremia was independently associated with a decreased likelihood of PVT (odds ratio [OR], 0.44, P < .001). African American patients had a lower incidence of PVT (OR, 0.70; P < .001). Variables associated with a higher incidence of PVT were: nonalcoholic steatohepatitis (OR, 1.15; P = .005), moderate-to-severe ascites (OR, 1.10; P = .008), and Hispanic ethnicity (OR, 1.2; P < .001).

CONCLUSION

Hyponatremia is associated with a lower rate of PVT independent of severity of liver disease and other thrombotic risk factors. This protective effect should be taken into consideration during the perioperative management of hyponatremia in patients undergoing LT.