Calcineurin inhibitor minimization using sirolimus leads to improved renal function in pediatric heart transplant recipients

The introduction of cyclosporine revolutionized the practice of immunosuppression for solid organ transplant recipients, and has resulted in a significant increase in survival. While CNI use has been the mainstay of immunosuppressive therapy in pediatric heart transplantation, CNIs have been associated with an increased risk of nephropathy leading to significant morbidity and mortality. We evaluated the effect on renal function of a CNI minimization protocol using SRL in pediatric heart transplant patients with CNI induced renal insufficiency. An IRB approved retrospective chart review and case control study was performed. There were 20 patients identified with renal insufficiency who had been converted to SRL (target 5-8 ng/mL) and cyclosporine (target 50-75 vs. 125-150 ng/mL). Renal insufficiency was defined as isotopic (Indium 111 DTPA) GFR <60 mL/min per 1.73 m(2) or sCr >1 mg/dL. Outcome variables evaluated were GFR and sCr at time of conversion and at two yr post conversion. Comparison was made with case control subjects matched for age at Tx, time from Tx to conversion, and initial GFR. The median age at Tx = 81 days (S.D. ±26), median time of conversion after Tx = 10 yrs (s.d. ±0.65). Self-limited/treatable side effects included hypercholesterolemia (10), neutropenia (6), aphthous ulcer (3), edema (2), anemia (2), and tremor (1). One patient rejected in the two yr prior to conversion, and one patient had two rejection episodes following conversion. GFR at conversion for study group was 51 ± 14 vs. 60 ± 2 at two yr, p = 0.018. GFR at inclusion for control group was 56 ± 20 vs. 53 ± 21, p = 0.253. This report demonstrates that minimizing CNI exposure by addition of SRL to the immunosuppressant regimen in pediatric heart transplant recipients result in improved renal function in comparison to historically managed patients. Furthermore, immunotherapy with SRL and lower-dose CNI can effectively prevent rejection with an acceptable side-effect profile.     

Risk factors for cardiovascular disease in pediatric renal transplant recipients

About 1,000 children develop end-stage renal disease (ESRD) each year in the United States and about 5,000 children are currently receiving dialysis. Children who develop ESRD are eligible to receive renal replacement therapy, including renal transplantation. There are inherent risks associated with transplantation, including renal insufficiency, infections, post-transplant lymphoproliferative disorder, and cardiovascular disease (CVD). Potential risk factors for CVD in pediatric renal transplant recipients include renal insufficiency, hyperlipidemia, hyperhomocysteinemia, inflammation, malnutrition, anemia, and hyperglycemia/insulin resistance. Despite evidence that many children may possess various risk factors for CVD post-renal transplantation, there are very few studies that have attempted to assess the link between these risk factors and CVD in pediatric renal transplant recipients.     

The profile of renal function over time in a cohort of pediatric heart transplant recipients

Abstract:  To assess the burden over time of renal dysfunction in pediatric heart transplant patients using an objective measure on an annual basis for serial comparison. GFR was measured at regular interval by nuclear medicine scintigraphy. Results were analyzed in relation to age, time post-transplantation, gender, and average calcineurin-inhibitor dose for the first two months post-transplantation. Results were compared with cGFR using the Schwartz equation. A total of 91 patients (56 males) transplanted between 1990 and 2004 underwent 373 GFR measurements. Median age at transplantation was 3.3 yr (birth – 17.8). Median first GFR at 0.7 yr (0.1–4.1) post-transplant was normal (94 mL/kg/1.73 m²). Freedom from at least mild renal insufficiency was 84% and 33% at one and five years post-transplant. Females had better renal function early post-transplant (GFR 105 mL/min/1.73 m²) but an increased probability of an abnormal GFR over time. Higher calcineurin inhibitor dose in the first two months post-transplantation was associated with an increasing probability of an abnormal GFR over time. The cGFR overestimated the measured GFR by 33 ± 26 mL/kg/1.73 m². Renal insufficiency is an important morbidity after pediatric transplantation with the majority of patients experiencing at least mild renal dysfunction. Calculated GFR significantly underestimates the burden of renal insufficiency in this patient population.     

Long-term renal function in pediatric liver and heart recipients

Long-term survivors of pediatric liver and heart transplantation are at risk for progressive renal dysfunction as a result of chronic exposure to calcineuron inhibitors. This class of drugs causes alterations in renal perfusion that can result in irreversible renal injury including afferent arteriopathy, glomerulosclerosis, tubular atrophy and interstitial fibrosis. Approximately 3-6% of pediatric liver and heart recipients will develop end stage renal failure. A much larger percentage has chronic renal insufficiency and hypertension. Children with significant renal compromise in the pretransplant period and those with significantly elevated serum creatinine levels during the first post-transplant year may be at the highest risk to develop irreversible renal injury in long-term follow-up. Serum creatinine is a poor screening tool as it rises late in the course when the injury may no longer be reversible. Strategies to minimize long-term exposure to calcineuron inhibitors may reduce the prevalence of renal insufficiency in this vulnerable population.     

Educational and learning morbidity in pediatric heart transplant recipients: A pediatric heart transplant society study

Educational development is an important component of quality of life for children with heart transplant. Aims include determining prevalence of and risk factors for modified education placement in a large representative sample of pediatric heart transplant recipients. Participants included 1495 patients (age 6‐18 years) from the PHTS database. Data on education placement and clinical predictors were collected at listing and at 1 and 3 years post‐transplant. At listing, 88% of patients were in typical education placement, while 12% were in modified education. Males (P = .02), those with CHD (P < .0001), those with non‐private insurance (P < .0001), and those with longer hospital stay (P = .001) were more likely to be in a modified education placement at time of listing. Age, race, listing status, mechanical support, and waitlist time were not significantly associated with placement. The prevalence of typical education placement was similar (87% at 1‐year and 86% at 3‐year) post‐transplant. Predictors of modified education placement at 3‐year follow‐up included placement at listing (OR = 12.9 [95% CI 7.6‐21.9], P < .0001), non‐private insurance (OR = 2.0 [95% CI 1.3‐3.2], P = .001), CHD (OR = 1.8 [95% CI 1.1‐2.7, P = .01), history of post‐transplant infection (OR = 1.9 [95% CI 1.2‐2.9, P = .007), and number of post‐transplant infections (OR = 1.3 [95% CI 1.1‐1.5, P = .002). Among pediatric heart transplant recipients, males, those with non‐private insurance, those with CHD, and those who experience post‐transplant infections are at greatest risk for modified academic placement, which persists for several years post‐transplant and deserves targeted intervention.     

Longitudinal renal function in pediatric heart transplant recipients: 20‐years experience

This study was initiated to assess the temporal trends of renal function, and define risk factors associated with worsening renal function in pediatric heart transplant recipients in the immediate post‐operative period. We performed a single‐center retrospective study in children ≤18 yr receiving OHT (1993–2012). The AKIN's validated, three‐tiered AKI staging system was used to categorize the degree of WRF. One hundred sixty‐four patients qualified for inclusion. Forty‐seven patients (28%) were classified as having WRF after OHT. Nineteen patients (11%) required dialysis after heart transplantation. There was a sustained and steady improvement in renal function in children following heart transplantation in all age groups, irrespective of underlying disease process. The significant factors associated with risk of WRF included body surface area (OR: 1.89 for 0.5 unit increase, 95% CI: 1.29–2.76, p = 0.001) and use of ECMO prior to and/or after heart transplantation (OR: 3.50, 95% CI: 1.51–8.13, p = 0.004). Use of VAD prior to heart transplantation was not associated with WRF (OR: 0.50, 95% CI: 0.17–1.51, p = 0.22). On the basis of these data, we demonstrate that worsening renal function improves early after orthotopic heart transplantation.     

Adiponectin levels and arteriosclerotic risk factors in pediatric renal transplant recipients

ADPN, a recently discovered adipocytokine, has attracted great attention because of its anti-atherogenic properties. It was suggested as a protective factor for the cardiovascular system because of its close correlation with several risk factors. Our aim was to investigate serum ADPN levels in pediatric RTR and to document possible relationships between ADPN and arteriosclerotic risk factors. Twenty-one RTR, aged 16.3 +/- 4.0 yr, and 23 healthy age and sex-matched control subjects were enrolled in this study. Serum lipid/lipoprotein fractions, homocysteine and ADPN levels as well as intima-media thickness of the cIMT were determined in both groups. Significantly higher serum ADPN (p < 0.001) and homocysteine (p < 0.05) levels as well as higher cIMT (p < 0.001) were found in RTR compared with the control subjects, whereas apolipoprotein B and lipoprotein (a) levels were not significantly different. HDL cholesterol was positively correlated with log ADPN (r = 0.585, p < 0.01). There were inverse correlations between log time post-transplantation and log ADPN as well as HDL cholesterol (r = -0.438, p < 0.05 and r = -0.578, p < 0.05, respectively). There were no correlation between log ADPN, log homocysteine, log apolipoprotein B, lipoprotein (a), creatinine clearance and cumulative steroid dose. Despite reasonable lipid profiles and remarkably elevated ADPN levels, our pediatric RTR with stable graft function displayed a risk for arteriosclerosis because of increased cIMT and mild hyperhomocysteinemia. Regarding the close positive correlation between ADPN and HDL cholesterol, it could be speculated that ADPN is a novel negative surrogate marker of arteriosclerosis. To our knowledge, this is the only report investigating levels and diverse correlates of ADPN in a pediatric RTR group. Further studies in larger groups of recipients are needed to clarify the interaction between arteriosclerotic risk factors and ADPN.     

Use of public health service increased risk kidneys in pediatric renal transplant recipients

With the opioid epidemic and expansion of “IR” classification, 25% of deceased donors are categorized PHS‐IR. Studies have assessed utilization of PHS‐IR organs among adults, but little is known about pediatric recipients. This retrospective cohort study from 2004‐2016 (IR period) aimed to: (a) assess IR kidney utilization patterns between adults and children; (b) identify recipient factors associated with transplant from IR donors among pediatric kidney recipients; and (c) determine geography's role in IR kidney utilization for children. The proportion of pediatric recipients receiving IR kidneys was significantly lower than adults (P < 0.001), even when stratified by donor mechanism of death (non‐overdose/overdose) and era. In mixed effects models accounting for clustering within centers and regions, older recipient age, later era (post‐PHS‐IR expansion), and blood type were associated with significantly higher odds of receiving an IR kidney (17 years era 5: OR 5.16 [CI 2.05‐13.1] P < 0.001; 18‐21 years era 5: OR 2.72 [CI 1.05‐7.06] P = 0.04; blood type O: OR 1.32 [CI 1.06‐1.64] P = 0.013). The median odds ratio for center within region was 1.77 indicating that when comparing two patients in a region, the odds of receiving an IR kidney were 77% higher for a patient from a center with higher likelihood of receiving an IR kidney. Utilization of PHS‐IR kidneys is significantly lower among pediatric recipients versus adult counterparts. More work is needed to understand the reasons for these differences in children in order to continue their access to this life‐prolonging therapy.     

Atorvastatin treatment for hyperlipidemia in pediatric renal transplant recipients

The objective of this prospective study was to determine the prevalence of hyperlipidemia in our pediatric renal transplant patients and to treat those with persistently elevated cholesterol and/or low-density lipoprotein (LDL) levels. All patients with a functioning renal allograft for greater than 6 months were studied (n = 18). Patients with cholesterol and/or LDL levels greater than the 95th percentile (n = 9) were commenced on an HMG-CoA reductase inhibitor, Atorvastatin and monitoring was performed for efficacy and adverse effects. Total serum cholesterol was elevated in 11 of 18 (61%) and triglyceride (TG) was elevated in 12 of 18 (67%) patients. Atorvastatin treatment was effective with a mean percentage reduction of total cholesterol of 41 +/- 10% (p < 0.01 vs. before treatment), LDL 57 +/- 7% (p < 0.01 vs. before treatment) and TG 44 +/-25% (p = 0.05 vs. before treatment). No adverse effects on allograft function or cyclosporin levels were experienced. Hyperlipidemia is a common problem and Atorvastatin is a safe and effective treatment in pediatric renal transplant recipients.     

Assessment of risk factors for cardiovasuclar disease in pediatric renal transplant patients

Pediatric renal TP recipients are at risk for CVD. We performed a cross-sectional study of the prevalence of RF for CVD in 45 long-term pediatric renal TP patients. The time since TP was 42 months. The GFR was 87.8 +/- 3.4 mL/min/1.73 m(2); 25/45 (56%) had Stage 2-4 CKD. A total of 33% had elevated SBP and 24% had high DBP; 57% had elevated SBP or DBP. A total of 20% had elevated serum CHOL levels, while 45% had high serum TG levels. A total of 42% had high HCY levels and 50% had low HCT levels. The vast majority (66.7%) had at least two RF for CVD. A total of 18.2% had abnormal post-TP echocardiography results. There was a negative correlation between GFR and SBP, DBP, serum CHOL, HCY, and BMI. There was a positive correlation between GFR and HCT. Serum CHOL was significantly lower and SBP and DBP trended lower in patients on a SF immunosuppression regimen. Similarly, SBP and DBP trended higher and CHOL was significantly higher in patients receiving SRL vs. mycophenolate mofetil. We conclude that the majority of pediatric renal TP patients exhibit multiple CVD RF.     

Donors' characteristics and impact on outcomes in pediatric heart transplant recipients

Organ availability and acceptability limit pediatric HTx. What characteristics define an unacceptable or high‐risk pediatric donor remains unclear. The purpose of this study was to characterize a large cohort of pediatric donors and determine the donor risk factors, including cumulative risk, that affect recipient survival. Data from the PHTS, a prospective multicenter study, were used to examine the impact of donor factors on the outcomes of patients listed <18 yr of age who received a HTx between 1993 and 2009. Donor data were available for 3149 of 3156 HTx (99.8%). Donor cause of death, need for inotropes, or CPR did not affect survival outcomes (p = 0.05). Ischemic time also did not have an impact on overall recipient survival; however, longer ischemic times negatively impacted one‐yr post‐transplant survival (p < 0.0001). There was no impact of cumulative risk factors on survival (p = 0.8). Although used in a minority of cases, hormonal therapy in the donor positively impacted survival (p = 0.03). In multivariate analysis, the only donor factor associated with decreased survival was smaller donor BSA, the other factors being related to the recipient characteristics. When analyzed by recipient age, there were no donor‐related factors that affected survival for those who received a transplant at <6 months of age. Longer ischemic time (p < 0.0001) and greater age difference between the recipient and donor (p = 0.0098) were donor‐related factors impacting early‐phase survival for recipients who received a graft at ≥10 yr of age. Factors perceived to define a marginal or high‐risk pediatric heart donor including inotrope use, CPR and donor cause of death may have less impact on outcomes than previously thought. Longer ischemic times did impact one yr, but not overall survival, and this impact was much greater with older donors. Parameters for accepting a donor heart can potentially be expanded, especially in the infant age group, but strong consideration should always be given to the interaction between ischemic time and donor age.     

Management of infants and young children with combined heart and kidney failure

Most infants and children referred for cardiac transplantation have low cardiac output with concurrent renal hypoperfusion leading to renal insufficiency and failure. This article is a review of the literature of and a single center's experience with combined heart and kidney failure in infants and children less than 10 yr of age. While 39 infants less than 10 yr of age were dialyzed pre- or peri-operatively, none required dialysis support at the time of discharge or in 5-10 yr follow-up. Based on our experience we recommend heart transplant alone in infants and young children with primary heart disease even though they have renal dysfunction.     

Renal function outcome in pediatric liver transplant recipients

The orthotopic liver transplantation (OLT) allows survival of children followed for severe hepatic injury, provided that the immunosuppressive treatment is prolonged. The nephrotoxicity of cyclosporine predicts the long-term outcome of the adult patients receiving a liver transplant. The aim of this study was to determine the long-term outcome of renal function in children receiving OLT. This study included 12 children, with a median for age of 7.1 yr (2-15 yr) at the time of OLT. The duration of follow-up was at least 4 yr, being 7 yr in 10 patients and more than 10 yr in seven. Renal function was evaluated with the serum level of creatinine, calculated glomerular filtration rate (cGFR), and measurement of glomerular filtration rate using chrome 51 ethylenediaminetetraacetate ((51)Cr EDTA) clearance performed at least once during follow-up. The doses and the serum concentrations (C(0)) of cyclosporine were reported at each study time. The cGFR decreased significantly 2 yr after the OLT [median (range): 106 mL/min/1.73 m(2) (71-150) at the time of OLT vs. 85 mL/min/1.73 m(2) (57-128) 2 yr after the OLT, p = 0.03], and decreased again between 7 and 10 yr after OLT [median (range): 99 mL/min/1.73 m(2) (76-125) 7 yr after OLT vs. 81 mL/min/1.73 m(2) (66-140) 10 yr after OLT, p = 0.04]. Six patients developed chronic renal failure (cGFR from 57 to 80 mL/min/1.73 m(2)) 2 yr after OLT associated with high doses of cyclosporine [median (range): 8.8 mg/kg/day (3.5-13)]. The cGFR overestimated renal function by 16% compared with the isotopic measurement of GFR (p = 0.03). Using the (51)Cr EDTA measurement, six of seven patients followed up more than 10 yr after OLT presented mild (n = 3) or moderate (n = 3) chronic renal failure. In our study, the majority of OLT recipients developed a chronic renal failure 10 yr after transplantation. Cyclosporine seems to be the most important factor responsible for the impairment of renal function. The use of the mycophenolate mofetil, a new immunosuppressive agent, allowing a reduction in the dose of cyclosporine, could minimize renal dysfunction. While awaiting the results of a prospective long-term study, close drug monitoring is advised.     

Cytomegalovirus transmission in pediatric renal transplant recipients during the window period

We report two CMV naïve children who received deceased donor renal transplants from a CMV IgG‐negative single donor. CMV IgG in both recipients and the donor were negative immediately prior to transplant. Both recipients had early recurrences of their original disease in their transplants, requiring multiple sessions of plasmapheresis. All blood products used were leukoreduced or CMV seronegative. A few days post‐transplant, both recipients developed significant positive CMV viremia. Both required initiation of oral valganciclovir. Case 1 responded to oral valganciclovir only while the case 2 had a delayed response to it and hence required intravenous ganciclovir with good response. When checked retrospectively, CMV IgM in the donor was positive along with positive CMV DNA PCR from the white cells. Here we describe a very unusual scenario of CMV transmission in two pediatric renal transplant recipients from a single donor during the CMV window period.     

Incidence,risk factors,and outcomes of opportunistic infections in pediatric renal transplant recipients

OIs present significant risks to patients following solid organ transplantation. The purpose of this study was to identify risk factors for the development of OIs after kidney transplantation in pediatric patients and to evaluate the impact of OIs on outcomes in this patient population. A single‐center retrospective longitudinal cohort analysis including pediatric patients 21 yr of age or younger transplanted from July 1999 to June 2013 at an academic medical center was conducted. Patients were excluded if they received multi‐organ transplant. A total of 175 patients were included in the study. Patients who developed OIs were more likely to be female and younger at the time of transplant. A six‐factor risk model for OI development was developed. Death, disease recurrence, and PTLD development were similar between groups but trended toward increased incidence in the OI group. Incidence of rejection was significantly higher in the OI group (p = 0.04). Patients who developed OIs had several important risk factors, including younger age, EBV‐negative serostatus, CMV donor (+)/recipient (?), biopsy‐proven acute rejection, ANC <1000, MMF dose >500 mg/m², and any infection. Incidence of rejection was higher in the OI group, but rate of graft loss was not statistically different.     

BK polyomavirus infection in pediatric heart transplant recipients: a prospective study

BKV infection and nephropathy complicate pediatric HTx, but the incidence and time course of the disease are unknown. We assessed the incidence of BKV infection and its association with kidney dysfunction in pediatric HTx recipients. A single center prospective study compared pediatric (<18 years) HTx recipients, with and without BKV infection, who received an allograft between September 2013 and December 2014. Screening of urine for BKV was performed prior to transplant, and at week 1, and at months 3, 6, 9, 12, and 15 months post‐transplantation. Serum for BKV DNA was assayed if BK viruria was present. Statistics included Fisher's exact test and Student's t test. Twelve patients were enrolled. Two patients were removed per parent request. Two (20%) had BK viruria and one (10%) had BK viremia. No patients developed BKVN. BK viruria was present within 2 months following transplantation. There were no identifiable risk factors for BKV infection and no statistically significant difference in renal function between the groups; however, there was a trend toward worsening renal function in those with BKV infection. BKV infection can occur early following heart transplantation. Screening for BK viruria should be considered in HTx recipients.     

Asymptomatic high Epstein-Barr viral load carriage in pediatric renal transplant recipients

High viral load carriage of EBV is one of the risks for PTLD in transplant recipients. We reviewed retrospectively in pediatric renal transplant recipients with EBV seronegative. EBV loads in peripheral blood and EBV-CTLs were measured every 1-3 months in 13 patients after grafting. Immunosuppressants were reduced when the patients were considered to have persistent high EBV loads (>1000 copies/μgDNA for over six months). All showed primary EBV infection: six with asymptomatic persistent high EBV loads (group A) and seven with neither EBV-associated symptoms nor persistent high EBV loads (group B). No patient developed PTLD in either group. Chronic rejection occurred in one patient in group A after immunosuppressants' reduction. There was no difference in renal dysfunction rates between the two groups. The maximum and increase rates in EBV loads were significantly higher in group A. The CTLs' percentage was significantly lower in group A when EBV loads first rose above 100 copies/μg DNA. This study suggests the possibility that EBV loads and CTLs' monitoring may be useful for avoidance of PTLD, as patients with asymptomatic persistent high EBV loads had higher EBV loads and lower percentages of CTLs.     

Predictors of cardiac allograft vasculopathy in pediatric heart transplant recipients

CAV remains a leading cause of late graft loss and mortality among survivors of pediatric heart transplantation. We sought to define the incidence of CAV and identify its predictors in pediatric heart transplant recipients. The OPTN/UNOS database was analyzed for pediatric recipients who underwent heart transplant between 1987 and 2011. The primary end‐point is time from heart transplantation to development of CAV (CAV‐free survival). To identify predictors of CAV‐free survival, demographic and transplant data were analyzed by the Kaplan–Meier survival method and Cox proportional hazards regression. Of 5211 pediatric heart transplant recipients with at least one‐yr follow‐up, the incidence of CAV at five, 10, and 15 yr was 13%, 25%, and 54%, respectively. Multivariate analysis found that risk of CAV was associated with the following variables: Recipient age 1–4 yr (HR 1.25), 5–9 yr (1.45), 10–18 yr (1.83), donor age >18 yr (1.34), re‐transplantation (2.14), recipient black race (1.55), and donor cigarette use (1.54). Older recipient and donor age, recipient black race, donor cigarette use, and re‐transplantation were highly associated with shorter CAV‐free survival.