Acute Kidney Injury After Pediatric Liver Transplantation

Lack of differences in outcomes between 3 immunosuppression protocols in the first year after pediatric liver transplantation: A multicenter study

Advances in immunosuppression have extended patient and graft survival rates after solid organ transplantation; however, this is not free of side effects. Balancing safety and efficacy is of paramount importance, particularly in the pediatric setting. Current literature comparing different protocols is scarce, and decisions are mostly guided by physician preference. We aimed to compare 3 different protocols from 4 different centers to identify differences in outcomes after 1 year of follow-up. A retrospective analysis of the databases of the participating centers was performed. Consecutive patients aged <18 years with a first liver-only transplant and no other underlying congenital or acquired immunodeficiency were included. Patients were classified according to the immunosuppression protocol as follows: group A (prednisone + tacrolimus + basiliximab), group B (prednisone + tacrolimus + basiliximab + antithymocyte globulin), and group C (prednisone + tacrolimus). Differences in survival, frequency of rejection, infections, and other complications were analyzed in the entire group (n = 97) and the group with biliary atresia (n = 48). After 1 year of follow-up, no differences in patient or graft survival were observed when comparing either the entire group (n = 97) or patients with biliary atresia only (n = 48). The frequencies of rejection and episodes of infection were similar. Renal function showed no differences either before or after transplantation or between the groups. Immunosuppression protocols used in this study appeared to be equally safe and effective. This could offer the opportunity to tailor them to the patient's individual characteristics without compromising the outcome.

Intraoperative kidney replacement therapy in acute liver failure

Paediatric acute liver failure (PALF) is often characterised by its rapidity of onset and potential for significant morbidity and even mortality. Patients often develop multiorgan dysfunction/failure, including severe acute kidney injury (AKI). Whilst the management of PALF focuses on complications of hepatic dysfunction, the associated kidney impairment can significantly affect patient outcomes. Severe AKI requiring continuous kidney replacement therapy (CKRT) is a common complication of both PALF and liver transplantation. In both scenarios, the need for CKRT is a poor prognostic indicator. In adults, AKI has been shown to complicate ALF in 25-50% of cases. In PALF, the incidence of AKI is often higher compared to other critically ill paediatric ICU populations, with reports of up to 40% in some observational studies. Furthermore, those presenting with AKI regularly have a more severe grade of PALF at presentation. Observational studies in the paediatric population corroborate this, though data are not as robust-mainly reflecting single-centre cohorts. Perioperative benefits of CKRT include helping to clear water-soluble toxins such as ammonia, balancing electrolytes, preventing fluid overload, and managing raised intracranial pressure. As liver transplantation often takes 6-10 h, it is proposed that these benefits could be extended to the intraoperative period, avoiding any hiatus. Intraoperative CKRT (IoCKRT) has been shown to be practicable, safe and may help sicker recipients tolerate the operation with outcomes analogous with less ill patients not requiring IoCKRT. Here, we provide a comprehensive guide describing the rationale, practicalities, and current evidence base surrounding IoCKRT during transplantation in the paediatric population.

Postoperative hypoalbuminemia and outcomes of pediatric liver transplantation

BACKGROUND

Hypoalbuminemia after liver transplantation (LT) is associated with acute kidney injury (AKI) and poor outcomes in adult LT recipients. This study was performed to examine the association between the postoperative serum albumin level and early postoperative outcomes of LT in children.

METHODS

This single-center retrospective review involved pediatric LT recipients (0-18 years old) treated from January 2013 to June 2020. All patients were admitted to PICU and received standard post-LT care protocol. We divided patients into low (< 30 g/L) and normal (> 30 g/L) groups based on postoperative albumin day 1 to 3.

RESULTS

Among 108 LT recipients, most had biliary atresia. The median age at the time of LT was 1.8 years [interquartile range (IQR), 1.5-5.7]. There were 18 patients in low albumin group [median albumin level, 27.9 g/L (IQR, 25.8-29.6) and 90 patients in normal albumin group [median albumin level, 34.5 g/L (IQR, 32.4-36.9). The low albumin group had significantly higher incidence of AKI, occurring in 20% of patients with a median onset of 2.5 days following LT (IQR, 1-5). Postoperative hypoalbuminemia (OR, 4.94; 95% CI, 1.32-18.47; p = 0.01) and a longer operative time (OR, 1.37; 95% CI, 1.01-1.47; p = 0.02) were independent risk factors for AKI by multivariable analysis. No significant differences between the two groups were found in other early postoperative outcomes.

CONCLUSION

Postoperative hypoalbuminemia was associated with early postoperative AKI following LT in children but not with other worsening outcomes.

Incidence and Risk Factors of Acute Kidney Injury in Pediatric Liver Transplant Patients: A Retrospective Study

Background

Acute kidney injury (AKI) significantly contributes to the mortality and morbidity rates among pediatric liver transplant (LT) recipients.

Objective

Our study aimed to assess the potential factors contributing to AKI in pediatric LT patients and to analyze the impact of AKI on postoperative mortality and hospitalization duration.

Materials and methods

About 235 pediatric LT patients under the age of 18 between the years 2015 and 2021 were evaluated retrospectively. The relationship between preoperative and intraoperative variables of the patients and AKI developed when the early postoperatıve period was assessed.

Results

A correlation was found between the patients' preoperative age, albumin levels, and AKI. AKI was found to be associated with the duration of surgery and intraoperative blood transfusion.

Conclusion

Our findings revealed that the severity of AKI in pediatric LT patients is linked to extended surgical durations and increased blood transfusions resulting from hemodynamically compromised blood loss. Furthermore, independent risk factors for AKI were identified as prolonged warm ischemia and the overall duration of the operation.

How to cite this article

Demiroz D, Colak YZ, Ozdes OO, Ucar M, Ali Erdogan M, Toprak HI, et al. Incidence and Risk Factors of Acute Kidney İnjury in Pediatric Liver Transplant Patients: A Retrospective Study. Indian J Crit Care Med 2024;28(1):75-79.

Development and validation of a multivariable prediction model in pediatric liver transplant patients for predicting intensive care unit length of stay

BACKGROUND

Liver transplantation is the life-saving treatment for many end-stage pediatric liver diseases. The perioperative course, including surgical and anesthetic factors, have an important influence on the trajectory of this high-risk population. Given the complexity and variability of the immediate postoperative course, there would be utility in identifying risk factors that allow prediction of adverse outcomes and intensive care unit trajectories.

AIMS

The aim of this study was to develop and validate a risk prediction model of prolonged intensive care unit length of stay in the pediatric liver transplant population.

METHODS

This is a retrospective analysis of consecutive pediatric isolated liver transplant recipients at a single institution between April 1, 2013 and April 30, 2020. All patients under the age of 18 years receiving a liver transplant were included in the study (n = 186). The primary outcome was intensive care unit length of stay greater than 7 days.

RESULTS

Recipient and donor characteristics were used to develop a multivariable logistic regression model. A total of 186 patients were included in the study. Using multivariable logistic regression, we found that age < 12 months (odds ratio 4.02, 95% confidence interval 1.20-13.51, p = .024), metabolic or cholestatic disease (odds ratio 2.66, 95% confidence interval 1.01-7.07, p = .049), 30-day pretransplant hospital admission (odds ratio 8.59, 95% confidence interval 2.27-32.54, p = .002), intraoperative red blood cells transfusion >40 mL/kg (odds ratio 3.32, 95% confidence interval 1.12-9.81, p = .030), posttransplant return to the operating room (odds ratio 11.45, 95% confidence interval 3.04-43.16, p = .004), and major postoperative respiratory event (odds ratio 32.14, 95% confidence interval 3.00-343.90, p < .001) were associated with prolonged intensive care unit length of stay. The model demonstrates a good discriminative ability with an area under the receiver operative curve of 0.888 (95% confidence interval, 0.824-0.951).

CONCLUSIONS

We develop and validate a model to predict prolonged intensive care unit length of stay in pediatric liver transplant patients using risk factors from all phases of the perioperative period.

Kidney injury associated with liver transplantation

INTRODUCTION

Kidney injury associated with paediatric liver transplantation (LT) is common, but its evaluation is challenging. Our aim was to analyse the presence of perioperative acute kidney injury (AKI) and study the prevalence of chronic kidney disease (CKD) using different glomerular filtration rate (GFR) estimation formulas.

METHODS

We conducted a cross-sectional study in a cohort of children aged less than 18 years with a history of LT followed up for 5.42 years. We estimated the GFR using the creatinine-based Schwartz bedside formula (2009), the cystatin C-based Caucasian Asian Pediatric and Adult cohort (CAPA) equation and the combined Full-Age Spectrum (FAS) formula as modified by Pottel. We analysed the agreement between them using the Bland-Altman method and the kappa statistic. We measured the albumin level in urine, the urine volume adjusted to 100 mL of GFR and blood pressure. We performed univariate and multivariate analyses of the risk factors associated with CKD.

RESULTS

The sample included 52 patients with a median age of 9.21 years. Fifteen (28.8%) had AKI. Five (10%) had CKD and the only associated risk factor was acute liver failure at the time of LT (odds ratio, 8.57; P = 0.04). There was poor agreement between the different estimation formulas. One patient was classified as having CKD with the Schwartz formula compared to four patients with the CAPA and the Pottel combined FAS formulas. Up to 42% of children without CKD had some positive marker of kidney injury.

CONCLUSIONS

The exclusive use of the 2009 Schwartz bedside formula to estimate GFR may lead to underdiagnosis of CKD in children post LT. Other markers of kidney injury are common, and their detection may help prevent the progression of CKD.

Prognostic value of blood urea nitrogen to serum albumin ratio for acute kidney injury and in-hospital mortality in intensive care unit patients with intracerebral haemorrhage: a retrospective cohort study using the MIMIC-IV database

OBJECTIVE

We sought to evaluate the prognostic ability of blood urea nitrogen to serum albumin ratio (BAR) for acute kidney injury (AKI) and in-hospital mortality in patients with intracerebral haemorrhage (ICH) in intensive care unit (ICU).

DESIGN

A retrospective cohort study using propensity score matching.

SETTING

ICU of Beth Israel Deaconess Medical Center.

PARTICIPANTS

The data of patients with ICH were obtained from the Medical Information Mart for Intensive Care IV (V.1.0) database. A total of 1510 patients with ICH were enrolled in our study.

MAIN OUTCOME AND MEASURE

The optimal threshold value of BAR is determined by the means of X-tile software (V.3.6.1) and the crude cohort was categorised into two groups on the foundation of the optimal cut-off BAR (6.0 mg/g). Propensity score matching and inverse probability of treatment weighting were performed to control for confounders. The predictive performance of BAR for AKI was tested using univariate and multivariate logistic regression analyses. Multivariate Cox regression analysis was used to investigate the association between BAR and in-hospital mortality.

RESULTS

The optimal cut-off value for BAR was 6.0 mg/g. After matching, multivariate logistic analysis showed that the high-BAR group had a significantly higher risk of AKI (OR, 2.60; 95% confidence index, 95% CI, 1.86 to 3.65, p<0.001). What's more, a higher BAR was also an independent risk factor for in-hospital mortality (HR, 2.84; 95% confidence index, 95% CI, 1.96 to 4.14, p<0.001) in terms of multivariate Cox regression analysis. These findings were further demonstrated in the validation cohort.

CONCLUSIONS

BAR is a promising and easily available biomarker that could serve as a prognostic predictor of AKI and in-hospital mortality in patients with ICH in the ICU.

Effects of serum sodium and chloride levels in the outcome of critically ill pediatric patients in the post-operative period of liver transplantation

BACKGROUND

Sodium and chloride disturbances have attracted increasing attention in recent years. Many pathophysiological effects are associated with hyperchloremia, including reduction in mean arterial pressure and acute renal disease. Pediatric patients undergoing liver transplantation are at risk of developing various electrolyte and biochemical abnormalities, with an impact on their postoperative outcomes.

OBJECTIVE

To analyze the impacts of serum sodium and chloride levels on prognosis of Pediatric Liver Transplant receptors.

METHODS

This was a retrospective analytical observational study performed in a single transplant reference center in Sao Paulo, Brazil. Included patients were pediatric patients who underwent liver transplantation between January 2015 and July 2019. Statistical regression analysis and General Estimating Equations analysis were performed to evaluate the impacts of sodium and chloride disturbances on the development of acute renal failure and mortality.

RESULTS

A total of 143 patients were included in this study. The main diagnosis was Biliary Atresia (62.9%). Twenty-seven patients died (18.9%), and graft dysfunction was the main cause of death (29.6%). The only variable individually associated with 28-days mortality was PIM-3 score (HR 1.59, CI 95% 1.165-2.177, p = 0.004). Forty-one patients (28.6%) developed moderate or severe AKI. PIM-3 score (OR 3.052, 95% CI 1.56-5.97, p = 0.001), hypernatremia (OR 3.49, 95% CI 1.32-9.23, p = 0.012), and hyponatremia (OR 4.24, 95% CI 1.52-11.85, p = 0.006) were independently associated with the development of moderate/severe AKI.

CONCLUSIONS

In pediatric patients after liver transplantation, PIM-3 score, and abnormal serum sodium levels were correlated with AKI development.

Posttransplant renal replacement therapy is an alarm signal for survival outcomes in pediatric liver transplantation

BACKGROUND

The impact of renal replacement therapy (RRT) on the long-term survival outcomes of pediatric liver recipients remains controversial.

METHODS

A total of 224 patients aged <18 years, who underwent liver transplantation (LT), were divided into two groups: patients who underwent renal replacement therapy (RRT) (group R, n = 25, 11.2%) and those who did not (group N, n = 199, 88.8%). The posttransplant patient survival outcomes according to RRT use constituted the primary end-point. RRT was initiated preoperatively in 12 patients (48.0%) and postoperatively in 13 [early: <6 months after LT (n = 5, 20.0%) and late: ≥6 months after LT (n = 8, 32.0%)]. The indications for RRT included liver disease involving the kidney (44.0%) and hepatorenal syndrome (56.0%).

RESULTS

The age at the time of LT (71.6 vs. 19.1 months) was higher, the pediatric end-stage liver disease score was lower (9.9 vs. 21.2), and the duration of hospitalization posttransplantation (41.0 vs. 27.0 days) was longer, while the rates of hepatic artery thrombosis (8.0% vs. 3.5%) were higher in group R (p < .05). The number of patients (60.0% vs. 93.0%; p < .001) and graft survival rates (68.0% vs. 93.0%; p < .001) were significantly lower in group R. Multivariate analysis revealed that posttransplant RRT and hepatic artery complications were risk factors for patient survival outcomes. Renal function was recovered in 7 patients (28.0%) in group R, and 9 (36.0%) eventually underwent kidney transplantation.

CONCLUSION

The survival outcomes of children requiring posttransplant RRT were significantly worse than those of children, who did not undergo RRT. Physicians should pay meticulous attention to patients requiring post-LT RRT.

Low albumin levels are independently associated with neonatal acute kidney injury: a report from AWAKEN Study Group

BACKGROUND

Data from adult and pediatric literature have shown an association between albumin levels and AKI. Whether hypoalbuminemia and neonatal AKI are associated has not been studied.

METHODS

We evaluated the association of albumin with early (during the first postnatal week) and late (after the first postnatal week) AKI for 531 neonates from the Assessment of Worldwide AKI Epidemiology in Neonates (AWAKEN) database and for 3 gestational age (GA) subgroups: < 29, 29 to < 36, and ≥ 36 weeks GA.

RESULTS

Low albumin levels were associated with increased odds of neonatal AKI; for every 0.1 g/dL decrease in albumin, the odds of late AKI increased by 12% on continuous analysis. After adjustment for potential confounders, neonates with albumin values in the lowest quartiles (< 2.2 g/dL) had an increased odds of early [Adjusted Odd Ratio (AdjOR) 2.5, 95% CI = 1.1-5.3, p < 0.03] and late AKI [AdjOR 13.4, 95% CI = 3.6-49.9, p < 0.0001] compared to those with albumin in the highest quartile (> 3.1 g/dL). This held true for albumin levels 2.3 to 2.6 g/dL for early [AdjOR 2.5, 95% CI = 1.2-5.5, p < 0.02] and late AKI [AdjOR 6.4, 95% CI = 1.9-21.6, p < 0.01]. Albumin quartiles of (2.7 to 3.0 g/dL) were associated with increased odds of late AKI. Albumin levels of 2.6 g/dL and 2.4 g/dL best predicted early (AUC = 0.59) and late AKI (AUC = 0.64), respectively. Analysis of albumin association with AKI by GA is described.

CONCLUSIONS

Low albumin levels are independently associated with early and late neonatal AKI. Albumin could be a potential modifiable risk factor for neonatal AKI.

Risk Factors and Consequences of Acute Kidney Injury After Noncardiac Surgery in Children

BACKGROUND

Postoperative acute kidney injury (AKI) is a serious complication that is associated with prolonged hospital stay, high risk of short-term postsurgical mortality, need for dialysis, and possible progression to chronic kidney disease. To date, very little data exist on the risk of postoperative AKI among children undergoing noncardiac surgical procedures. We used data from a large multicenter cohort to determine the factors associated with AKI among children who underwent inpatient noncardiac surgical procedures and its impact on the postoperative course.

METHODS

We utilized the National Surgical Quality Improvement Program Pediatric participant user files to identify a cohort of children who underwent inpatient surgery between 2012 and 2018 (n = 257,439). We randomly divided the study population into a derivation cohort of 193,082 (75%) and a validation cohort of 64,357 (25%), and constructed a multivariable logistic regression model to identify independent risk factors for AKI. We defined AKI as the occurrence of either acute renal failure or progressive renal insufficiency within the 30 days after surgery.

RESULTS

The overall rate of postoperative AKI was 0.10% (95% confidence interval [CI], 0.09-0.11). In a multivariable model, operating times longer than 140 minutes, preexisting hematologic disorder, and preoperative sepsis were the strongest independent predictors of AKI. Other independent risk factors for AKI were American Society of Anesthesiologists (ASA) physical status ≥III, preoperative inotropic support, gastrointestinal disease, ventilator dependency, and corticosteroid use. The 30-day mortality rate was 10.1% in children who developed AKI and 0.19% in their counterparts without AKI (P < .001). Children who developed AKI were more likely to require an extended hospital stay (≥75th percentile of the study cohort) relative to their peers without AKI (77.4% vs 21.0%; P < .001).

CONCLUSIONS

Independent preoperative risk factors for AKI in children undergoing inpatient noncardiac surgery were hematologic disorder, preoperative sepsis, ASA physical status ≥III, inotropic support, gastrointestinal disease, ventilator dependency, and steroid use. Children with AKI were 10 times more likely to die and nearly 3 times more likely to require an extended hospital stay, relative to their peers without AKI.

Trajectory of AKI in hospitalized pediatric patients - impact of duration and repeat events

BACKGROUND

Peak severity of acute kidney injury (AKI) is associated with mortality in hospitalized pediatric patients. Other factors associated with AKI, such as number of AKI events, severity of AKI events, and time spent in AKI may also have associations with mortality. Characterization of these events could help to evaluate patient outcomes.

METHODS

Pediatric inpatients (<19 years of age) from 2011-2019 who were not on maintenance renal replacement therapy and had least one serum creatinine (SCr) obtained during hospital admission were included. Percent change in SCr from the minimum value in the prior 7 days was used for AKI staging according to KDIGO criteria. Maximum value for age appropriate normal was used for patients with only one SCr. Repeat AKI events were classified in patients if KDIGO criteria was met more than once with at least one SCr value between episodes that did not meet KDIGO criteria.Patient demographics were summarized and incidence of AKI was determined along with associations with mortality. AKI characterizations for the admission were developed including: AKI, repeat (>1) AKI, AKI severity (maximum KDIGO stage), and total number of AKI events. AKI duration as percent admission days in a KDIGO stage and AKI percent velocity were determined. Kaplan-Meier analysis was performed for time to 30 day survival by AKI characterization. A mixed effects logistic regression model with mortality as the dependent variable and nested in patients was developed incorporating patient variables and AKI characterizations.

RESULTS

A total of 184,297 inpatient encounters met study criteria (male 51.7%, Age 7.8 years (IQR 2.5, 13.8), mortality 0.56%). Hospital length of stay was 1.9 days (IQR 0.37, 4.8 days), 15.4% had an intensive care unit admission and 12.2% underwent mechanical ventilation. AKI occurred in 5.6% (n = 10,246) of admissions (Stage I = 4.5% (n = 8,310), Stage II = 1.3% (n = 2,363), Stage III=0.77% (n = 1,423)) and repeat AKI events occurred in 1.92% (n = 3,558). AKI was associated with mortality (OR 6.0, 95% CI 4.8, 7.6, p < 0.001) and increasing severity (KDIGO maximum stage) was associated with increased mortality. Multiple AKI events were also associated with mortality (p < 0.001),. Duration of AKI was associated with mortality (p < 0.001) but AKI velocity was not (p > 0.05).

CONCLUSIONS

AKI occurs in 5.6% of the pediatric inpatient population and multiple AKI events occur in ∼30% of these patients. Maximum KDIGO stage is most strongly associated with mortality. Multiple AKI events and AKI duration should also be considered when evaluating patient outcomes.

PCRRT Expert Committee ICONIC Position Paper on Prescribing Kidney Replacement Therapy in Critically Sick Children With Acute Liver Failure

Management of acute liver failure (ALF) and acute on chronic liver failure (ACLF) in the pediatric population can be challenging. Kidney manifestations of liver failure, such as hepatorenal syndrome (HRS) and acute kidney injury (AKI), are increasingly prevalent and may portend a poor prognosis. The overall incidence of AKI in children with ALF has not been well-established, partially due to the difficulty of precisely estimating kidney function in these patients. The true incidence of AKI in pediatric patients may still be underestimated due to decreased creatinine production in patients with advanced liver dysfunction and those with critical conditions including shock and cardiovascular compromise with poor kidney perfusion. Current treatment for kidney dysfunction secondary to liver failure include conservative management, intravenous fluids, and kidney replacement therapy (KRT). Despite the paucity of evidence-based recommendations concerning the application of KRT in children with kidney dysfunction in the setting of ALF, expert clinical opinions have been evaluated regarding the optimal modalities and timing of KRT, dialysis/replacement solutions, blood and dialysate flow rates and dialysis dose, and anticoagulation methods.

Acute and chronic kidney disease after pediatric liver transplantation: An underestimated problem

Acute and chronic kidney injuries represent critical issues after liver transplantation (LTx), but whereas renal dysfunction in adult transplant patients is well documented, little is known about its prevalence in childhood. It is a challenge to accurately evaluate renal function in patients with liver disease, due to several confounding factors. Creatinine-based equations estimating glomerular filtration rate, validated in nephropathic patients without hepatic issues, are frequently inaccurate in end-stage liver disease, underestimating the real impact of renal disease. Moreover, whereas renal issues observed within 1 year from LTx were often related to acute injuries, kidney damage observed after 5-7 years from LTx, is due to chronic, irreversible mechanisms. Most immunosuppression protocols are based on calcineurin inhibitors (CNIs) and corticosteroids, but mycophenolate mofetil or sirolimus could play significant roles, also in children. Early diagnosis and personalized treatment represent the bases of kidney disease management, in order to minimize its close relation with increased mortality. This review analyzed acute and chronic kidney damage after pediatric LTx, also discussing the impact of pre-existent renal disease. The main immunosuppressant strategies have been reviewed, highlighting their impact on kidney function. Different methods assessing renal function were reported, with the potential application of new renal biomarkers.