High Burden of Subclinical Cardiovascular Target Organ Damage After Pediatric Liver Transplantation

Adult and late adolescent complications of pediatric solid organ transplantation

BACKGROUND

There have been over 51 000 pediatric solid organ transplants since 1988 in the United States alone, leading to a growing population of long-term survivors who face complications of childhood organ failure and long-term immunosuppression.

AIMS

This is an educational review of existing literature.

RESULTS

Pediatric solid organ transplant recipients are at increased risk for risk for cardiovascular and kidney disease, skin cancers, and growth problems, though the severity of impact may vary by organ type. Pediatric recipients often are able to complete schooling, maintain a job, and form family and social networks in adulthood, though at somewhat lower rates than the general population, but face additional challenges related to neurocognitive deficits, mental health disorders, and discrimination.

CONCLUSIONS

Transplant centers and research programs should expand their focus to include long-term well-being. Increased collaboration between pediatric and adult transplant specialists will be necessary to better understand and manage long-term complications.

Etiology, risk factors and management of hypertension post liver transplantation

BACKGROUND

Cardiovascular events are one of the most important causes of morbidity and mortality in the long-term follow-up of liver transplant recipients. Hypertension is a significant cardiovascular risk factor that occurs frequently after pediatric liver transplantation. Chronic use of immunosuppressants - mainly calcineurin inhibitors - plays a major role in the development of post-transplant hypertension and circadian disturbances such as flattening of the nocturnal blood pressure dip. This requires special attention in children given the long timeframe during which immunosuppressive therapy is necessary. Careful and structured blood pressure monitoring and adequate treatment of hypertension are essential to optimize the quality of life and life expectancy of pediatric liver transplant patients. However, evidence-based guidelines for monitoring and management of post-transplant hypertension and its complications are lacking.

METHODS

We conducted a comprehensive review of the current knowledge and practices concerning post-transplant hypertension. The databases Pubmed, Embase, Web of Science and Google Scholar were scanned with the following keywords: pediatric liver transplantation, immunosuppression, tacrolimus, cardiovascular effects, hypertension, heart function, kidney function, circadian rhythm, mechanism, monitoring, and management.

RESULTS

In this review, we describe the incidence and etiology of hypertension in pediatric liver transplant recipients, the underlying mechanisms and characteristics of calcineurin inhibitor-induced hypertension, and the consequences of and risk factors for post-transplant hypertension. We hereby present an overview of the current practices in blood pressure monitoring and antihypertensive treatment as well as an algorithm for the evaluation and management of hypertension post liver transplantation. Finally, we discuss knowledge gaps and suggestions for future research.

Differences in Physical Activity Levels between Healthy and Transplanted Children: Who Needs More Tips?

BACKGROUND

Advances in the medical-surgical field have significantly increased the life expectancy of patients undergoing solid organ transplantation but this exposes patients to long-term complications due to chronic therapies and changes in lifestyle. It is known that children affected by pathology tend to be more sedentary and inactivity represents a further risk factor for the onset of non-communicable diseases. The aim of the present study was to compare the lifestyle of two groups of young patients: one group of healthy subjects (HG) and one group of kidney or liver transplant recipients (TG).

METHODS

Patients were asked to complete Physical Activity Questionnaire for Older Children (PAQ-C).

RESULTS

A total of 104 subjects were recruited (50.9% male, mean age 12.8 ± 3.16 years old). No significant differences were observed in the final score between groups when comparing subjects based on health condition (Healthy 2.69 ± 0.65 vs. Transplant Group 2.42 ± 0.88), the intensity of sports activities (Competitive 2.82 ± 0.59 vs. Not Competitive 2.53 ± 0.7) or type of transplant (Liver 2.51 ± 0.91 vs. Kidney 2.16 ± 0.75).

CONCLUSION

The results of this study showed a worrying reality: children are engaged in low levels of physical activity regardless of their health status and in general the level of activity does not reach the recommended values even in the absence of contraindications. So, it is necessary to encourage healthy children to practice more PA and to introduce PA prescriptions for transplanted children to prevent their health from deteriorating due to sedentariness.

Hypertension in Pediatric Solid Organ Transplant Recipients

PURPOSE OF REVIEW

To review the current literature regarding hypertension (HTN) following pediatric solid organ transplant (SOTx), including definition, prevalence, risk factors, outcomes, and treatment.

RECENT FINDINGS

In recent years several new guidelines for the definition, monitoring, and management of pediatric HTN have been published, but with no specific recommendations regarding SOTx recipients. HTN remains highly prevalent, yet underdiagnosed and undertreated in kidney transplant (KTx) recipients, especially when ambulatory blood pressure monitoring (ABPM) is utilized. There are little data regarding its prevalence in other SOTx recipients. HTN in this population is multifactorial and is associated with HTN status prior to Tx, demographic factors (age, sex, and race), weight status, and immunosuppression protocol. HTN is associated with subclinical cardiovascular (CV) end-organ damage, including left ventricular hypertrophy (LVH) and arterial stiffness, yet there are no recent data regarding its long-term outcomes. There are also no updated recommendations regarding the optimal management of HTN in this population. Given its high prevalence and the young age of this population facing years at increased CV risk, post-Tx HTN requires more clinical attention (routine monitoring, frequent application of ABPM, better BP control). Additional research is needed for a better understanding of its long-term outcomes as well as its treatment and treatment goals. Much more research is needed regarding HTN in other pediatric SOTx populations.

Incidence of cardiovascular disease and mortality in childhood solid organ transplant recipients: a population-based study

BACKGROUND

With improved survival among children after transplantation, our understanding of the risk for developing other comorbidities is improving, yet little is known about the long-term risk of cardiovascular events and mortality after solid organ transplantation.

METHODS

In a cohort study using health administrative data, we compared cardiovascular events in children (n = 615) with liver, lung, kidney, small bowel, or multi-organ transplant at the Hospital for Sick Children, Toronto, Canada, with asthmatic children (n = 481,697) between 1996 and 2014. Outcomes included non-fatal cardiovascular events, cardiovascular death, all-cause mortality, and a composite of non-fatal and fatal cardiovascular events. Time-stratified Cox proportional hazards models were used.

RESULTS

Among 615 children, 317 (52%) were recipients of kidneys, 253 (41%) of livers, and the remaining 45 (7%) had lung, small bowel, or multi-organ transplants. Median follow-up was 12.1 [7.2, 16.7] years. Non-fatal incident cardiovascular events were 34 times higher among solid organ transplant recipients than non-transplanted children (incidence rate ratio (IRR) 34.4, 95% CI: 25.5, 46.4). Among transplant recipients, the cumulative incidence of non-fatal and fatal cardiovascular events was 2.3% and 13.0%, 5 and 15 years after transplantation, respectively.

CONCLUSIONS

Increased rate of cardiovascular events in children after transplantation highlights the need for surveillance during transition into adulthood and beyond. A higher resolution version of the Graphical abstract is available as Supplementary information.

Preliminary Evaluation of Sedentary Lifestyle in Italian Children after Solid Transplant: What Role Could Physical Activity Play in Health? It Is Time to Move

BACKGROUND

Advances in the medical-surgical field have significantly increased survival after solid organ transplantation in the pediatric population. However, these patients are predisposed to the development of long-term complications (e.g., cardiovascular disease). The therapeutic role of physical activity (PA) to counteract these complications is well known. The purpose of the study was to investigate the level of PA in a pediatric population after solid organ transplantation.

METHODS

In the first 4 weeks at the beginning of the school year, the Physical Activity Questionnaire for Older Children and Adolescents was administered to young patients who had previously undergone solid transplants at our institute.

RESULTS

Questionnaires of 49 patients (57.1% female, mean age 13.2 ± 3.5 years) were analyzed and 32.7% of subjects did not perform any exercise during school physical education classes. Only 24% practiced a moderate quantity of exercise in the previous week (2-3 times/week) and 72% engaged in sedentary behaviors during weekends.

CONCLUSIONS

Preliminary data confirmed that young recipients are still far from meeting the minimum indications of the World Health Organization on PA and sedentary behavior. It will be necessary to increase their involvement in PA programs in order not only to increase their life expectancy but also to improve their quality of life.

Telomere length is associated with intima-media thickness in pediatric liver transplant patients: A prospective cohort study

Leukocyte telomere length (LTL) is a marker for biological age. Pediatric liver transplant recipients show a high rate of subclinical atherosclerosis, indicated by elevated intima-media thickness (IMT). We hypothesized that atherosclerosis is associated with biological age in these patients and investigated the course of LTL over time. We measured LTL from peripheral blood leukocytes by quantitative polymerase chain reaction and IMT from 97 pediatric patients after liver transplantation in a prospective cohort study. Of the patients, 71% (n = 69) had two or more assessments (total, 228 observations; median follow-up, 1.1 years). Lower LTL was associated with higher IMT (β = -0.701, p = 0.01) and higher aspartate aminotransferase (β = -0.001, p = 0.02), adjusted for age, sex, and age at transplantation. Of the patients, 45% showed decreasing LTL over time, whereas 55% exhibited stable LTL. Patients with stable LTL showed a decrease in IMT (median, -0.02 mm/year) and a decrease of tacrolimus trough levels (median, -0.08 μg/L/year). LTL is associated with IMT independent of age in pediatric liver transplant patients, suggesting that early aging contributes to the high burden of subclinical cardiovascular damage and may furthermore negatively affect the graft.

Prognosis of Children Undergoing Liver Transplantation: A 30-Year European Study

OBJECTIVES

The European Liver Transplant Registry has been collecting data on virtually all pediatric liver transplant (PLT) procedures in Europe since 1968. We analyzed patient outcome over time and identified parameters associated with long-term patient outcome.

METHODS

Participating centers and European organ-sharing organizations provided retrospective data to the European Liver Transplant Registry. To identify trends, data were grouped into consecutive time spans: era A: before 2000, era B: 2000 to 2009, and the current era, era C: since 2010.

RESULTS

From June 1968 until December 2017, 16 641 PLT were performed on 14 515 children by 133 centers. The children <7 years of age represented 58% in era A, and 66% in the current era (P <.01). The main indications for PLT were congenital biliary diseases (44%) and metabolic diseases (18%). Patient survival at 5 years is currently 86% overall and 97% in children who survive the first year after PLT. The survival rate has improved from 74% in era A to 83% in era B and 85% in era C (P <.0001). Low-volume centers (<5 PLT/year) represented 75% of centers but performed only 19% of PLT and were associated with a decreased survival rate. In the current era, however, survival rates has become irrespective of volume. Infection is the leading cause of death (4.1%), followed by primary nonfunction of the graft (1.4%).

CONCLUSIONS

PLT has become a highly successful medical treatment that should be considered for all children with end-stage liver disease. The main challenge for further improving the prognosis remains the early postoperative period.

Targeting Calcineurin Inhibitor-Induced Arterial Hypertension in Liver Transplanted Children Using Hydrochlorothiazide

OBJECTIVE

Arterial hypertension (AH) is the most common toxic effect of calcineurin inhibitor (CNI)-based immunosuppression in children after liver transplantation (LT). Activation of the renal sodium chloride cotransporter (NCC) by CNIs has been described as a major cause of CNI-induced AH. Thiazides, for example, hydrochlorothiazide (HCTZ), can selectively block the NCC and may ameliorate CNI-induced AH after pediatric LT.

METHODS

From 2005 thru 2015 we conducted a retrospective, single-center analysis of blood pressure in 2 pediatric cohorts (each n = 33) with or without HCTZ in their first year after LT. All patients received CNI-based immunosuppression. According to AAP guidelines, AH was defined as stage 1 and stage 2. Cohort 1 received an HCTZ-containing regimen to target the CNI-induced effect on the NCC, leading to AH. Cohort 2 received standard antihypertensive therapy without HCTZ.

RESULTS

In children who have undergone LT and been treated with CNI, AH overall was observed less frequently in cohort 1 vs cohort 2 (31% vs 44%; ns). Moreover, severe AH (stage 2) was significantly lower in cohort 1 vs 2 (1% vs 18%; p < 0.001). Multivariate analysis revealed HCTZ as the only significant factor with a protective effect on occurrence of severe stage 2 AH. While monitoring safety and tolerability, mild asymptomatic hypokalemia was the only adverse effect observed more frequently in cohort 1 vs 2 (27% vs 3%; p = 0.013).

CONCLUSIONS

Targeting NCC by HCTZ significantly improved control of severe CNI-induced AH and was well tolerated in children who underwent LT. This effect may reduce the risk of long-term end-organ damage and improve quality of life.

Cardiovascular Burden Is High in Pediatric Lung Transplant Recipients

BACKGROUND

Cardiovascular morbidity is common in adults after lung transplantation (LTx) but has not been described for pediatric LTx recipients. Early subclinical cardiovascular damage is reflected by increases in pulse wave velocity (PWV; indicating arteriosclerosis), intima-media thickness (IMT; indicating atherosclerosis), and left ventricular mass index (LVMI; indicating left ventricular hypertrophy).

METHODS

We annually assessed 47 pediatric LTx recipients in a prospective longitudinal study (144 observations, mean 3.1 visits/patient, range of 1-4 visits, mean follow-up 2.2 y).

RESULTS

At inclusion, increased PWV and IMT were detected in 13% and 30%, respectively, and elevated LVMI was detected in 33%. Higher PWV was associated with male sex, longer time since LTx, higher diastolic blood pressure, and lower glomerular filtration rate. Male sex and lower hemoglobin levels were associated with higher IMT, and the presence of diabetes was associated with higher LVMI.

CONCLUSIONS

Pediatric LTx recipients suffer from a high and sustained burden of subclinical cardiovascular damage. In light of improving long-term outcomes, cardiovascular morbidity needs to be addressed. Our analysis identified classical and nonclassical risk factors to be associated with the measures for cardiovascular damage, which could serve as targets for intervention.

Parental Disease Specific Knowledge and Its Impact on Health-Related Quality of Life

OBJECTIVE

Structured education programs have been shown to improve somatic outcome and health-related quality of life (HRQOL) in a variety of chronic childhood diseases. Similar data are scarce in paediatric liver transplantation (pLTx). The purpose of this study was to examine the relationship of parental disease-specific knowledge and psychosocial disease outcome in patients after pLTx.

METHODS

Parents of 113 children (chronic liver disease n = 25, after pLTx n = 88) completed the transplant module of the HRQOL questionnaire PedsQL, the "Ulm quality of life inventory for parents of children with chronic diseases" ULQUI, and a tailor-made questionnaire to test disease-specific knowledge.

RESULTS

Parental knowledge was highest on the topic of "liver transplantation" and lowest in "basic background knowledge" (76% and 56% correct answers respectively). Knowledge performance was only marginally associated with HRQOL scores, with better knowledge being related to worse HRQOL outcomes. In contrast, self-estimation of knowledge performance showed significant positive correlations with both PedsQL and ULQUI results.

CONCLUSION

Patient HRQOL and parental emotional wellbeing after pLTx are associated with positive self-estimation of parental disease-specific knowledge. Objective disease-specific knowledge has little impact on HRQOL. Parental education programs need to overcome language barriers and address self-efficacy in order to improve HRQOL after pLTx.

Clinical parameters and biomarkers predicting spontaneous operational tolerance after liver transplantation: A scoping review

Indefinite allograft acceptance after immunosuppression withdrawal (ISW), also known as operational tolerance (OT), can occur spontaneously after liver transplantation (LT), but reliable and reproducible prognosis of OT versus non-OT outcomes remains elusive. To prime this, systematic extraction of OT-predictive factors from the literature is crucial. We provide the first comprehensive identification and synthesis of clinical parameters and biomarkers predicting spontaneous OT in non-autoimmune/non-replicative viral LT recipients selected for ISW. We searched Embase, Medline, the Cochrane Central Register of Controlled Trials, clinicaltrials.gov, and the World Health Organization International Clinical Trials Registry Platform for articles, conference abstracts, and ongoing trials. We contacted principal investigators of stand-alone abstracts and ongoing trials for unpublished data and screened citations and references of eligible articles. Twenty-three articles reporting on 11 completed ISW studies, 13 abstracts, and five trial registry entries were included. Longer time between LT and ISW was the only clinical parameter that may increase the incidence of OT. Prognostic biomarkers conspicuously differed between pediatric and adult ISW candidates. These included allograft gene expression patterns and peripheral blood immune exhaustion markers for adults, and histological allograft scores for children. Our results will foster cross-validation efforts to facilitate safe and harmonized candidate selection for successful ISW.

Efficacy and Safety of Immunosuppression Withdrawal in Pediatric Liver Transplant Recipients: Moving Toward Personalized Management

BACKGROUND AND AIMS

Tolerance is transplantation's holy grail, as it denotes allograft health without immunosuppression and its toxicities. Our aim was to determine, among stable long-term pediatric liver transplant recipients, the efficacy and safety of immunosuppression withdrawal to identify operational tolerance.

APPROACH AND RESULTS

We conducted a multicenter, single-arm trial of immunosuppression withdrawal over 36-48 weeks. Liver tests were monitored biweekly (year 1), monthly (year 2), and bimonthly (years 3-4). For-cause biopsies were done at investigators' discretion but mandated when alanine aminotransferase or gamma glutamyltransferase exceeded 100 U/L. All subjects underwent final liver biopsy at trial end. The primary efficacy endpoint was operational tolerance, defined by strict biochemical and histological criteria 1 year after stopping immunosuppression. Among 88 subjects (median age 11 years; 39 boys; 57 deceased donor grafts), 33 (37.5%; 95% confidence interval [CI] 27.4%, 48.5%) were operationally tolerant, 16 were nontolerant by histology (met biochemical but failed histological criteria), and 39 were nontolerant by rejection. Rejection, predicted by subtle liver inflammation in trial entry biopsies, typically (n = 32) occurred at ≤32% of the trial-entry immunosuppression dose and was treated with corticosteroids (n = 32) and/or tacrolimus (n = 38) with resolution (liver tests within 1.5 times the baseline) for all but 1 subject. No death, graft loss, or chronic, severe, or refractory rejection occurred. Neither fibrosis stage nor the expression level of a rejection gene set increased over 4 years for either tolerant or nontolerant subjects.

CONCLUSIONS

Immunosuppression withdrawal showed that 37.5% of selected pediatric liver-transplant recipients were operationally tolerant. Allograft histology did not deteriorate for either tolerant or nontolerant subjects. The timing and reversibility of failed withdrawal justifies future trials exploring the efficacy, safety, and potential benefits of immunosuppression minimization.

Cardiovascular involvement after liver transplantation: role of non-alcoholic fatty liver disease and non-alcoholic steatohepatitis

Patients submitted to liver transplantation (LT) are exposed to high risk of cardiovascular (CV) complications which are the main determinants of both short-term and long-term morbidity and mortality in LT. Non-alcoholic fatty liver disease (NAFLD) is a very frequent condition in general population and is associated with a high risk of cardiovascular disease (CVD) which represents the first cause of death of these patients. NAFLD is predicted to become the first indication to LT and nowadays is also frequently detected in patients submitted to LT for other indications. Thus, the risk of CVD in patients submitted to LT is forecasted to increase in the next years. In this review the extent of CV involvement in patients submitted to LT and the role of NAFLD, either recurring after transplantation or as de novo presentation, in increasing CV risk is analysed. The risk of developing metabolic alterations, including diabetes, hypertension, dyslipidemia and weight gain, all manifestations of metabolic syndrome, occurring in the first months after LT, is depicted. The different presentations of cardiac involvement, represented by early atherosclerosis, coronary artery disease, heart failure and arrhythmias in patients with NAFLD submitted to LT is described. In addition, the tools to detect cardiac alterations either before or after LT is reported providing the possibility for an early diagnosis of CVD and an early therapy able to reduce morbidity and mortality for these diseases. The need for long-term concerted multidisciplinary activity with dietary counseling and exercise combined with drug treatment of all manifestations of metabolic syndrome is emphasized.

Prospective assessment of subclinical cardiovascular damage and associated factors in liver transplant recipients

Cardiovascular (CV) disease plays a major role after liver transplantation (LT). This prospective study assessed subclinical CV damage after LT by measuring pulse wave velocity (PWV), intima-media thickness (IMT) and left-ventricular mass index (LVMI) and characterized associated risk factors. We included 112 patients with a median of 1.8 years after LT (q1-q3 0.9-9.2). Fifty-three percent (n = 59) of patients had ≥2 annual assessments (median follow-up 1.6 years, q1-q3 1.1-2.0), with a total of 195 assessments. We found increased PWV (indicating arteriosclerosis) in 16% (n = 17), elevated IMT in 5% (n = 5; indicating atherosclerosis) and increased LVMI in 25% (n = 24; indicating left-ventricular hypertrophy). A linear mixed model analysis using all 195 assessments revealed that higher age and systolic blood pressure (BP) were associated with higher PWV (β = 0.069, P < 0.001 and β = 0.022, P = 0.005) and higher IMT (β = 0.005, P < 0.001 and β = 0.001, P = 0.029), while higher body mass index was associated with higher IMT (β = 0.004, P = 0.023). Higher systolic BP (β = 0.200, P = 0.034), male sex (β = 8.847, P = 0.031) and lower glomerular filtration rate (β = -0.288, P < 0.001) were associated with higher LVMI. Our data highlight not only the rate of subclinical CV damage in LT patients, but also the impact of classical CV risk factors (such as BP and body mass index) which outweighed LT-related factors. These modifiable risk factors are suitable targets for interventions to reduce CV morbidity in LT patients.

Gesundheit und Fitness von deutschen Schulkindern

Hintergrund

Übergewicht und Bewegungsmangel stellen bei Kindern ein Risiko für kardiovaskuläre Erkrankungen dar. Das Ziel der Studie war, den kardiovaskulären Gesundheitsstatus und die Fitness deutscher Grund- und Gesamtschülerinnen und -schüler sowie mögliche Einflussfaktoren zu erfassen.

Methodik

In einer prospektiven Querschnittsstudie wurden 357 Kinder (9,6 ± 1,7 Jahre) auf kardiovaskuläre Risikofaktoren untersucht. Die Pulswellengeschwindigkeit (PWV) als Maß für die arterielle Gefäßelastizität sowie die Fahrradergometrie zur Einschätzung der Fitness wurden bestimmt.

Ergebnisse

24 % der Kinder waren übergewichtig (Body-Mass-Index, BMI >90. Perzentile) oder adipös (BMI >97. Perzentile). Nahezu alle diese Kinder litten an einer viszeralen Adipositas (99 %). Bei Kindern mit Übergewicht/Adipositas war häufiger eine geringere Gefäßelastizität nachweisbar (PWV „standard deviation score“, SDS 0,8 ± 1,0 vs. 0,2 ± 0,9 bei Kindern ohne Übergewicht, p < 0,001; PWV-Werte >95. Perzentile 24 % vs. 3 %). Das Vorliegen von Übergewicht/Adipositas, Grundschulalter, höherer Blutdruck und niedrigeres „High Density Lipoprotein“(HDL)-Cholesterin waren unabhängige Prädiktoren für geringere Gefäßelastizität. Zudem zeigten Kinder mit Übergewicht/Adipositas einen höheren systolischen Blutdruck, ein nachteiligeres Fettstoffwechselprofil, höhere Harnsäure- und Glutamat-Pyruvat-Transaminase(GPT)-Werte sowie schlechtere körperliche Fitness und einen höheren Medienkonsum. Es bestand eine signifikante Assoziation von BMI und glomerulärer Filtrationsrate.

Diskussion

Das mit erhöhtem BMI und reduzierter Fitness einhergehende kardiovaskuläre Risiko wird durch weitere Risikofaktoren für die Entwicklung eines metabolischen Syndroms verstärkt. Zusätzlich finden sich Hinweise, dass bereits strukturelle Veränderungen an den Gefäßen vorliegen. Unsere Daten legen eine umfassende Beurteilung des individuellen kardiovaskulären Risikos bei Kindern mit Übergewicht nahe und unterstreichen die Notwendigkeit, Präventionsmaßnahmen früh in den Alltag von Kindern zu implementieren, um die kardiovaskuläre Morbidität im Erwachsenenalter zu verringern.