Impact of sarcopenia in infants with liver transplantation for biliary atresia

Optimizing the pediatric transplant candidate

PURPOSE OF REVIEW

Advances in pediatric transplant parallel those in adult populations; however, there remain critical unique considerations and differences that require specialized knowledge and a specific skill set to optimize care afforded to the pediatric transplant candidate. We introduce general themes regarding optimization of the transplant candidate that are unique to children.

RECENT FINDINGS

The pathologies leading to pediatric organ transplant candidacy differ from adults and a precise understanding of the physiologies and natural histories of such diseases is critical for optimized care. Regardless of etiology, comorbidities including malnutrition, sarcopenia, and developmental delay are seen and often require disease and organ specific approaches to management. Additionally, an understanding of the concepts of developmental immunology and their relevance to transplant is critical.

SUMMARY

When looking to optimize pretransplant care, awareness of the pediatric-specific challenges by the transplant community in addition to organ- and age-specific management strategies enable the best outcomes for children awaiting solid organ transplantation.

Criteria for immediate extubation after pediatric liver transplantation in a single pediatric liver transplant center in Japan

Immediate extubation (IE) following liver transplantation (LT) has become the standard practice, even for pediatric patients. However, no preoperative or postoperative case selection protocols for IE are currently available. We have developed selection criteria for IE following pediatric LT. The aim of this study is to assess the safety and effectiveness of these selection criteria and anesthetic management protocol implemented in our hospital for IE after pediatric LT.

METHOD

This was a retrospective study. The records of all cases undergoing LT in our center from January 2016 to December 2020 were collected. We excluded cases > 18 years old at the time of LT. Enrolled cases were divided into two groups: cases with immediate extubation (IE) or without immediate extubation (NIE). We compared preoperative conditions, intraoperative management, and postoperative courses. Finally, we classified NIE group patients into cases extubated at postoperative day 1 (early; E-NIE) and others (delayed; D-NIE) and compared their underlying diseases and postoperative courses.

RESULTS

In the IE group, there were 81 cases, while the NIE group consisted of 185 cases. All patients in the IE group were successfully extubated without any instances of re-intubation due to respiratory failure. Within the E-NIE group, comprising 130 cases, all patients were ultimately extubated without the need for tracheostomy. However, in the D-NIE group, which encompassed 53 cases, seven patients required tracheostomy.

CONCLUSION

In our center, the implementation of our anesthesia management protocol and the use of pre/postoperative case selection criteria have allowed for the safe practice of IE following pediatric LT. However, it should be noted that patients who cannot be extubated by Postoperative Day 1 (POD1) may be at an increased risk of requiring a tracheostomy. When contemplating IE, it is crucial to take into account the disease-specific physiological aspects and surgical site situations.

Pediatric body composition based on automatic segmentation of computed tomography scans: a pilot study

BACKGROUND

Body composition during childhood may predispose to negative health outcomes later in life. Automatic segmentation may assist in quantifying pediatric body composition in children.

OBJECTIVE

To evaluate automatic segmentation for body composition on pediatric computed tomography (CT) scans and to provide normative data on muscle and fat areas throughout childhood using automatic segmentation.

MATERIALS AND METHODS

In this pilot study, 537 children (ages 1-17 years) who underwent abdominal CT after high-energy trauma at a Dutch tertiary center (2002-2019) were retrospectively identified. Of these, the CT images of 493 children (66% boys) were used to establish normative data. Muscle (psoas, paraspinal and abdominal wall) and fat (subcutaneous and visceral) areas were measured at the third lumbar vertebral (L3) level by automatic segmentation. A representative subset of 52 scans was also manually segmented to evaluate the performance of automatic segmentation.

RESULTS

For manually-segmented versus automatically-segmented areas (52 scans), mean Dice coefficients were high for muscle (0.87-0.90) and subcutaneous fat (0.88), but lower for visceral fat (0.60). In the control group, muscle area was comparable for both sexes until the age of 13 years, whereafter, boys developed relatively more muscle. From a young age, boys were more prone to visceral fat storage than girls. Overall, boys had significantly higher visceral-to-subcutaneous fat ratios (median 1.1 vs. 0.6, P<0.01) and girls higher fat-to-muscle ratios (median 1.0 vs. 0.7, P<0.01).

CONCLUSION

Automatic segmentation of L3-level muscle and fat areas allows for accurate quantification of pediatric body composition. Using automatic segmentation, the development in muscle and fat distribution during childhood (in otherwise healthy) Dutch children was demonstrated.

Sarcopenia is associated with osteopenia and impaired quality of life in children with genetic intrahepatic cholestatic liver disease

BACKGROUND

Sarcopenia occurs in pediatric chronic liver disease, although the prevalence and contributing factors in genetic intrahepatic cholestasis are not well-described. The objective of this study was to measure muscle mass in school-aged children with genetic intrahepatic cholestasis and assess relationships between sarcopenia, clinical variables, and outcomes.

METHODS

Estimated skeletal muscle mass (eSMM) was calculated on dual-energy x-ray absorptiometry obtained in a Childhood Liver Disease Research Network study of children with bile acid synthesis disorders(BASD) alpha-1 antitrypsin deficiency (a1ATd), chronic intrahepatic cholestasis (CIC), and Alagille syndrome (ALGS). Relationships between eSMM, liver disease, and transplant-free survival were assessed.

RESULTS

eSMM was calculated in 127 participants (5-18 y): 12 BASD, 41 a1ATd, 33 CIC, and 41 ALGS. eSMM z-score was lower in CIC (-1.6 ± 1.3) and ALGS (-2.1 ± 1.0) than BASD (-0.1 ± 1.1) and a1ATd (-0.5 ± 0.8, p < 0.001). Sarcopenia (defined as eSMM z-score ≤- 2) was present in 33.3% of CIC and 41.5% of ALGS participants. eSMM correlated with bone mineral density in the 4 disease groups (r=0.52-0.55, p < 0.001-0.07), but not serum bile acids, bilirubin, aspartate aminotransferase/platelet ratio index, or clinically evident portal hypertension. Of the 2 patients who died (1 with sarcopenia) and 18 who underwent liver transplant (LT, 4 with sarcopenia), eSMM z-score did not predict transplant-free survival. eSMM z-score correlated with the Physical Pediatric Quality of Life Inventory score (r=0.38-0.53, p = 0.007-0.04) in CIC and a1ATd.

CONCLUSION

Severe sarcopenia occurs in some children with ALGS and CIC. The lack of correlation between eSMM and biochemical cholestasis suggests mechanisms beyond cholestasis contribute to sarcopenia. While sarcopenia did not predict transplant-free survival, LT and death were infrequent events. Future studies may define mechanisms of sarcopenia in genetic intrahepatic cholestasis.

Establishment and validation of reference values for abdominal skeletal muscle compartments in children

BACKGROUND & AIMS

Sarcopenia, resulting from skeletal muscle loss, is a serious concern in children, for whom nutrition and physical activity are essential for growth. In sarcopenia research, the skeletal muscle mass is often obtained from computed tomography (CT) cross-sectional images in both adults and children; however, the method of evaluating skeletal muscle using CT, especially the area range to be measured, has not yet been validated in children. The aim of this study is to establish reference values for three compartments of the abdominal skeletal muscle area (aSMA) obtained from cross-sectional CT images, and to validate the differences among them by assessing correlations with physical development.

METHODS

We conducted a single-centre, retrospective, cross-sectional study and included patients aged 1-17 years who underwent abdominal CT at Chiba University Hospital from 2007 to 2020. Patients with chronic diseases such as malignant tumours and inflammatory bowel disease were excluded from the analysis. aSMA was obtained from CT cross-sections at the lumbar L3-L4 intervertebral disc level by dividing it into three compartments: the psoas muscle area (PMA), paraspinal muscle area (PSMA), and total skeletal muscle area (TSMA). Quartile regression curves by sex and muscle compartment were generated using non-crossover and nonparametric regression quantile estimation. The correlation between each compartment of aSMA with height and weight was assessed using Spearman's rank correlation coefficient.

RESULTS

We analysed the abdominal CT images of 593 children (male: n = 335, female: n = 258) and generated curves predictive for the 5th, 25th, 50th, 75th, and 95th percentiles for each compartment of aSMA by sex. In patients aged 13 years and older, boys had significantly larger aSMA areas than girls in all three compartments. Among the three compartments, PSMA had the strongest correlation coefficient with height and weight for both boys and girls.

CONCLUSIONS

We generated quantile regression curves for three aSMA compartments obtained from cross-sectional CT images and established reference values in children. PSMA values were most strongly correlated with height and weight among the three aSMA compartments.

Perspectives on Sarcopenia as a Predictor for Outcomes in Pediatric Patients with Chronic Liver Disease

Sarcopenia, a pathologic deficiency of muscle mass and function, has emerged as an important secondary feature of many chronic disease states. For adults with end stage liver disease, there are multiple mechanisms which contribute to sarcopenia and its presence has proven to be an important predictor of morbidity and mortality. In children, there are only a limited number of reports which investigate the role of sarcopenia in liver disease. These studies, which are discussed and summarized in this review, report small, single-center analyses with dissimilar study cohorts and varying clinical definitions. Still, children meeting the study entry criteria have sarcopenia with a reported prevalence of 24-70%. When assessed, sarcopenia appears to be associated with more severe disease but is independent of the Pediatric End-Stage Liver Disease (PELD) score and does not correlate with age, gender, or traditional anthropometric measures such as weight, height, weight-for-height, or body mass index (BMI). While individual studies may identify sarcopenia as a statistically significant risk factor for certain post-transplant outcomes such as longer ICU stay, longer duration of intubation, repeat operation, development of serious infection, longer hospital stay, death, or long-term growth failure, such associations are not consistently replicated across studies. Finally, although various methods of muscle mass quantification are utilized, the most reported is the total psoas muscle surface area (tPMSA) on computed tomography. This method, along with others such as skeletal muscle area and skeletal muscle index, have had normative values recently defined and these collective efforts should enable researchers a common basis of comparison when delineating sarcopenia, and its impact, across various study populations in future investigations - including in children with liver disease.

Preoperative myopenia and myosteatosis and their impact on postoperative complications in children with inflammatory bowel disease

PURPOSE

To assess the severity of preoperative myopenia and myosteatosis in pediatric patients with inflammatory bowel disease (IBD) and examine their impact on postoperative complications.

METHODS

The subjects of this retrospective study were 30 pediatric patients with IBD (22 with ulcerative colitis (UC) and 8 with Crohn's disease (CD)) and 67 age-matched controls. Preoperative body mass index (BMI), psoas muscle index (PMI), and intramuscular adipose tissue content were compared between the patient groups, to investigate their association with postoperative complications.

RESULTS

BMI and PMI were significantly lower in the IBD patients than in the controls (p < 0.0001, p < 0.0001, respectively). CD was associated with significantly lower BMI and PMI (p = 0.01, p = 0.01, respectively) than UC. Intramuscular adipose tissue content was comparable between the IBD patients and the controls and between the UC and CD patients. There were no significant differences among the three indices in relation to the presence or absence of postoperative complications in patients with IBD. When limited to surgical site infection (SSI), only PMI was significantly lower in the patients with SSI than in those without SSI (p = 0.04).

CONCLUSIONS

Although BMI and PMI were lower preoperatively in pediatric IBD patients than in controls, only myopenia seemed to affect the development of SSI.

Sarcopenia prevalence in pediatric intestinal transplant recipients: Implications on post-transplant outcomes

BACKGROUND

Sarcopenia has been associated with poor surgical outcomes but has not been studied in pediatric intestinal transplantation. We aimed to determine sarcopenia prevalence in intestinal transplant recipients and the association of sarcopenia with outcomes.

METHODS

We performed a cross-sectional retrospective chart review of intestinal transplant recipients from 2000-present. We estimated total psoas muscle area (tPMA) at L3-L4 and L4-L5 from computed tomography scans prior to or in the immediate peri-operative period. Sarcopenia was defined by tPMA below the 5^th percentile for age and sex. We built a Cox-proportional hazards model to determine the association between sarcopenia and patient and graft survival.

RESULTS

Of the 56 intestinal transplant recipients included, 36 (64%) were sarcopenic. Graft survival was 79% at one year and 59% at five years. Overall patient survival was 86% at one year and 76% at five years. Peri-transplant sarcopenia was associated with improved graft survival (Hazard ratio 0.42, 95% confidence interval: 0.20-0.88) but not overall survival (Hazard ratio 0.47, 95% confidence interval: 0.19-1.20).

CONCLUSIONS

In this first report of sarcopenia in pediatric intestinal transplant, we found a high sarcopenia prevalence without an association with worse outcomes. The potential improved graft survival in sarcopenic patients along with underlying mechanisms warrant further exploration.

Sarcopenia and Fat Mass in Children With Chronic Liver Disease and Its Impact on Liver Transplantation

In adults, weight loss and sarcopenia are prognostic indicators of poor outcomes for patients awaiting liver transplant (LT). We tested the hypothesis that sarcopenia in children awaiting LT was related to poor outcomes.

Methods

Children with end-stage chronic liver disease undergoing assessment for LT were recruited into an observational longitudinal study. Anthropometry and body composition (BC; whole-body dual-energy x-ray absorptiometry scan) were assessed before and, on average, 1 year after LT.

Results

Eleven children (6 females:5 males) were assessed (4.7 to 17.2 years; median, 9.9) at baseline. Nine children went on to have an LT. The aspartate aminotransferase-to-platelet ratio index had a significant positive correlation with trunk lean mass and trunk lean mass index (LMI) SD score (SDS). At baseline, 4 patients were sarcopenic with appendicular LMI SDS less than -1.96. All fat mass and fat mass index (FMI) SDSs were within the normal range (above -1.96). There was a strong negative correlation between FMI SDS and height SDS. After transplant, there was a significant reduction in trunk LMI from 1.20 to -0.51 (95% CI, 1.03-2.4; P < 0.01). Body mass index SDS had a negative correlation with days to discharge after transplant. The majority of patients discharged after 16 days were sarcopenic. One year after transplantation, all patients were alive with normal graft function regardless of BC before LT.

Conclusion

FMIs were normal regardless of LMIs and correlated negatively with height. BC was related to days to discharge after LT but not to outcomes a year after LT.

Organ-Specific Comorbidities Are Associated With Distinct Complications After Liver Transplantation for Biliary Atresia

Although transplant outcomes for biliary atresia (BA) have improved, there are few data to predict the risk of specific posttransplant complications. We therefore defined the impact of comorbidities in BA on posttransplant outcomes. Patients enrolled in the Society of Pediatric Liver Transplantation registry from 2011 to 2019 (n = 1034) were grouped by comorbidities of >1.0% incidence: any supplemental feeding, dialysis, other abdominal surgery (not Kasai portoenterostomy [KPE]), hepatopulmonary syndrome, and cardiac disease requiring intervention. Demographic and outcome data were compared using the Kruskal-Wallis, chi-square, and log-rank tests. Cox proportional hazards models and binary logistic regression were performed for modeling. Patients with BA with comorbidities comprised 77% (n = 799) of our cohort and had evidence of greater medical acuity, including higher calculated Pediatric End-Stage Liver Disease scores and hospitalizations in the intensive care unit before transplant (P < 0.001 for both) versus those without comorbidities. After transplant, patients with BA with comorbidities had more graft loss (P = 0.02), longer initial hospitalization and intubation (P < 0.001 for both), and increased rates of reoperation (P = 0.001) and culture-proven infection (P < 0.001) within 30 days after transplant. Only patients with BA with comorbidities on supplemental feed had increased rates of patient death (P = 0.02). Multivariate analysis identified lower z weight and higher creatinine as risk factors for graft and patient loss in patients with BA with comorbidities. Prior KPE was protective against culture-proven infection and vascular complications within 30 and 90 days, respectively. Patients with BA with comorbidities have evidence of higher medical acuity at transplant and reduced graft survival; however, they overall did not experience greater incidence of patient death. Our data provide organ-system-specific data to risk-stratify patients with BA and posttransplant outcomes.

Sarcopenia in Children with Solid Organ Tumors: An Instrumental Era

Sarcopenia has recently been studied in both adults and children and was found to be a prognostic marker for adverse outcome in a variety of patient groups. Our research showed that sarcopenia is a relevant marker in predicting outcome in children with solid organ tumors, such as hepatoblastoma and neuroblastoma. This was especially true in very ill, high-risk groups. Children with cancer have a higher likelihood of ongoing loss of skeletal muscle mass due to a mismatch in energy intake and expenditure. Additionally, the effects of cancer therapy, hormonal alterations, chronic inflammation, multi-organ dysfunction, and a hypermetabolic state all contribute to a loss of skeletal muscle mass. Sarcopenia seems to be able to pinpoint this waste to a high degree in a new and objective way, making it an additional tool in predicting and improving outcome in children. This article focuses on the current state of sarcopenia in children with solid organ tumors. It details the pathophysiological mechanisms behind sarcopenia, highlighting the technical features of the available methods for measuring muscle mass, strength, and function, including artificial intelligence (AI)-based techniques. It also reviews the latest research on sarcopenia in children, focusing on children with solid organ tumors.

Sarcopenia in children with chronic liver disease: Prevalence and impact on liver transplant outcomes

Sarcopenia is a clinical condition characterized by a reduction in muscle mass, which typically affects adult patients; however, it has recently been recognized in pediatric literature. Few studies in children with chronic liver disease (CLD) undergoing liver transplantation (LT) have investigated the role of sarcopenia, with controversial results. The aim of our study was to assess the prevalence and impact of sarcopenia among children with CLD who are candidates for LT. We conducted a retrospective, single-center study at Bambino Gesù Children's Hospital (Rome, Italy) from July 2016 to July 2021, evaluating all children (0-16 years old) with CLD listed for LT with an abdomen computed tomography imaging available before LT. The total psoas muscle surface area (t-PMSA) was defined as the sum of left and right psoas muscle surface area measured at L4-L5 on axial images. The t-PMSA z-score was calculated according to reference data, and sarcopenia was defined as a t-PMSA z-score of ≤-2 (1-16 years) or a psoas muscle index [PMI; PMI = t-PMSA/(100 × BSA)] of <50th percentile of the population examined (<1 year). Clinical, laboratory, and LT outcome data were collected from all the patients with CLD. 27 out 48 (56%) of the patients aged 1-16 years were sarcopenic. No differences were noted in anthropometrics, nutritional support, liver function tests, model for ESLD (MELD), or pediatric ESLD (PELD) scores between patients with and without sarcopenia. The former showed a higher prevalence of respiratory complications (66.7% vs. 42.1%) and need for inotropes (40.7% vs. 10.8%) after LT. Among patients aged 0-1 years (n: 36), those with reduced muscle mass (50%) had a longer hospitalization time (44 vs. 24 days) and higher incidences of multi-organ failure syndrome (38.9% vs. 0%) and intensive care unit-related infections (61.1% vs. 27.8%) compared to those with greater muscle mass. t-PMSA and PMI were statistically significant predictors of LT outcomes. Sarcopenia is a reliable index of frailty in children with CLD, as its presence is associated with the risk of a more challenging LT. Future studies will have to investigate the functional aspects of sarcopenia and conceive preventive measures of muscle wasting in CLD patients.

Impact of muscle mass on the prognosis of liver transplantation for infants with biliary atresia

BACKGROUND

Sarcopenia in adult cirrhotic patients is associated with increased morbidity and mortality whereas in children it is still being studied. Anthropometric variables in cirrhotic children are not reliable for assessing muscle mass as they may be altered by ascites, edema, and organomegaly. Measuring the area of the psoas showed good correlation with muscle mass in adults. We aimed to study in cirrhotic infants undergoing liver transplantation the association of the psoas area with liver transplant prognosis as well as with several analytical and anthropometric parameters used to evaluate nutritional status.

METHODS

Retrospective cohort of 29 infants with cirrhosis due to biliary atresia who underwent abdominal CT scan as a pre-transplant study. We measured the psoas muscle index (PMI) at L4-L5 since it best correlates with muscle mass in pediatric patients. As there are no validated cut-off points to define sarcopenia in children under one year of age, PMI was recorded as a continuous variable and correlated with different prognostic, clinical, and analytical variables. The SPSS 17.0 package was used for statistical analysis and a P < 0.05 was considered significant.

RESULTS

29 infants (10 boys, 19 girls) were studied. 62% were Caucasian and the rest were South American. The mean age at CT scan was 8.5 months (range 3-15 months). There was a negative correlation between PMI and days of admission prior to liver transplant, previous infections, and bone fractures. Among the analytical parameters, cholinesterase, albumin, and prealbumin correlated positively with PMI (P < 0.05). No relationship was observed with anthropometric parameters: weight, height, BMI, brachial perimeter, or bioimpedance. During surgery, patients with lower PMI had a greater need for plasma transfusion, and in the immediate postoperative period, there was a longer stay in intensive care, more days of mechanical ventilation, and more days of hospital admission (P < 0.05). On the contrary, no relationship was found with other complications: bleeding, re-interventions, biliary leaks, rejection, thrombosis, re-transplantation, or infections.

CONCLUSIONS

The decrease in muscle mass is associated with increased morbidity in infants with biliary atresia undergoing liver transplantation. Muscle mass in these patients cannot be adequately assessed with anthropometric measurements commonly used in the clinic.

Utility of Preoperative Computed Tomography-Based Body Metrics in Relation to Postoperative Complications in Pediatric Liver Transplantation Recipients

Computed tomography (CT)-derived body metrics such as skeletal muscle index (SMI), psoas muscle index (PMI), and subcutaneous fat area index (ScFI) are measurable components of sarcopenia, frailty, and nutrition. While these body metrics are advocated in adults for predicting postoperative outcomes after liver transplantation (LT), little is known about their value in pediatric populations. This study assessed the relation between preoperative CT-based body metrics and postoperative short-term outcomes in pediatric LT recipients. Patients aged 0-18 years who underwent a primary LT were retrospectively included (n = 101; median age 0.5 years; range 0.2-17.1). SMI, PMI, and ScFI were derived from preoperative axial CT slices. Postoperative outcomes and complications within 90 days were correlated with the CT-based body metrics. To classify postoperative infections, the Clavien-Dindo (CD) classification was used. Subgroup analyses were performed for age groups (<1, 1-10, and >10 years old). An optimal threshold for test performance was defined using Youden's J-statistic and receiver operating characteristic curve as appropriate. ScFI was significantly (P = 0.001) correlated with moderate to severe postoperative infections (CD grade 3-5) in children aged <1 year, with the optimal ScFI threshold being ≤27.1 cm² /m² (sensitivity 80.4% and specificity 77.8%). A weak negative correlation between SMI and the total duration of hospital stay (R = -0.3; P = 0.01) and intensive care unit (ICU) stay (R = -0.3; P = 0.01) was observed in children aged <1 year. No other associations between CT-based body metrics and postoperative outcomes were shown. In children aged <1 year with cirrhotic liver disease undergoing LT, preoperative CT-based body metrics were correlated with moderate to severe postoperative infections (ScFI) and with longer duration of hospital and ICU stay (SMI), and thus can be considered important tools for pre-LT risk assessment.