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.     

Health‐related quality of life in pediatric intestinal transplantation

To determine HRQOL after pediatric intestinal transplantation. Thirty‐four IT survivors from 1999 to 2012 were asked to complete age‐specific HRQOL non‐disease‐specific questionnaires: TAPQOL (0–4 yr), KINDL‐R (5–7 yr; 8–12 yr; 13–17 yr), and SF‐36v2 (>18 yr), all validated with Spanish population. Primary caregiver completed a SF‐36 questionnaire and CBI. Thirty‐one participants were included. Median age was 10.2 yr (1–29) and time after transplant 4.4 yr (0–13). Overall patient scores were 78.2 ± 10.6 (n = 8), 83.3 ± 9.7 (n = 6), 72.2 ± 9.21 (n = 6), 80.5 ± 12.4 (n = 7), and 82.2 ± 12.4 (n = 4) for each age group. Highest scores were obtained for vitality (group I), self‐esteem (group IV), and physical and social functioning and emotions (group V). Lowest scores were obtained in appetite and behavior (I), family and school (III), and chronic disease perception (III, IV). No significant differences were found between caregivers and their children. CBI showed stress in 52%. SF‐36 for caregivers was lower than general population. No significant differences were found depending on relevant clinical and sociodemographic data. HRQOL was acceptable and improved with age and time since transplantation. Parents had a slighter own QOL and worse perception of health than their children. When successful, intestinal transplantation allows a normal life in most patients and can be offered as an attractive option.     

Empiric switch from calcineurin inhibitor to sirolimus‐based immunosuppression in pediatric heart transplantation recipients

Sirolimus is used in heart transplant patients with CAV and CNI‐induced nephropathy. However, little is known regarding the tolerability, rejection rate, and effect on renal function when used empirically in children. We describe our experience with the empiric use of a sirolimus‐based immunosuppressive regimen in pediatric heart transplantation recipients. We reviewed records of patients in whom conversion was attempted to a CNI‐free sirolimus‐based regimen. Rejection episodes and measures of renal function were recorded. We attempted to convert 20 patients, of which 16 were successful. In total, six of 20 patients (30%) experienced adverse effects. Of the 16 converted, four patients converted to sirolimus due to CNI‐induced disease (three nephropathy, one CAV), while 12 patients (mean age 5.5 yr, range 0.1–21 yr; 33% female; 33% with a history of congenital heart disease) were empirically switched to sirolimus at a mean of 2.3 yr after transplant. Follow‐up was available for a mean of 2.5 yr after conversion (range 0.5–8.3 yr). The rate of rejection while taking CNIs was 0.18 rejection episodes per patient‐year (total of five episodes), compared with 0.03 rejection episodes per patient‐year (total of one episode) while on sirolimus. Renal function, in terms of GFR, significantly improved after sirolimus conversion at latest follow‐up (from 86 ± 37 mL/min to 130 ± 49 mL/min, p = 0.02). Here, we demonstrate the potential benefit of empiric use of sirolimus in pediatric heart transplant patients in a CNI‐free regimen. Larger and longer studies are needed to further clarify risks of rejection and adverse effect profiles.     

Cardiovascular risk factors and cardiac disorders in long‐term survivors of pediatric liver transplantation

The MetS and cardiovascular disease are leading causes of late morbidity in adult liver transplantation recipients; however, limited data are available in pediatric liver transplantation. A single‐center retrospective review was undertaken for patients who had a liver transplantation before 18 yr of age and were >5 yr post‐transplantation, to study the prevalence of MetS, its components, and cardiac disorders. Fifty‐eight patients were included in the study with a mean age at transplantation of 6.3 ± 6.1 yr and mean follow‐up of 14.1 ± 6.0 yr. Of the study group, 41.4% were overweight or obese, with ongoing prednisone use and increased duration of follow‐up being significant risk factors. Fifty‐three patients had sufficient data for determining MetS, which was present in 17% of the patients. Although the prevalence of MetS is low in pediatric liver transplant recipients, it is associated with CKD and prednisone therapy (p < 0.05). Echocardiography data were available for 23 patients, of whom 43.4% had LVH and 13% had evidence of PH. The spectrum of cardiac disorders in this population is much wider than in adults.     

Clinical predictors of autoimmune and severe atopic disease in pediatric heart transplant recipients

Autoimmune and allergic diseases cause morbidity and diminished quality of life in pediatric organ transplant recipients. We hypothesize that younger age at transplantation and immunosuppression regimen play a role in the development of immune‐mediated disease following heart transplant. A single institution retrospective review identified all patients undergoing heart transplant at ≤18 yr of age from 1987 to 2010 who survived ≥1 yr. Using medical record and database review, patients were evaluated for development of autoimmune or severe allergic disease. Of 129 patients who met criteria, seven patients (5.4%) with autoimmune or severe atopic disease were identified. Immune‐mediated diseases included inflammatory bowel disease (n = 3), eosinophilic esophagitis/colitis (n = 4), and chronic bullous disease of childhood (n = 1). Patients <1 yr of age at transplant were at greater risk of developing autoimmune disease than patients 1–18 yr at transplant (OR = 9.3, 95% CI 1.1–79.2, p = 0.02). All affected patients underwent thymectomy at <1 yr of age (7/71 vs. 0/58, p = 0.02). In our experience, heart transplantation in infancy is associated with the development of immune‐mediated gastrointestinal and dermatologic diseases. Further study is needed to determine risk factors for the development of immune‐mediated disease to identify best practices to decrease incidence.     

Donor‐specific anti‐HLA antibody production following pediatric ABO‐incompatible heart transplantation

ABO‐i heart transplantation can be performed in infants with end‐stage heart failure to increase organ availability. The development of newly detected DSAs is associated with decreased cardiac graft survival, and the effect of ABO‐i transplantation on DSA production is unknown. We examined DSA production and rejection frequency in infant recipients of ABO‐i and ABO‐c heart transplants via a retrospective cohort study of infant heart transplant recipients transplanted at a single pediatric center between January 2004 and November 2014. Patients were included if they were less than 1 year of age at transplant and had a minimum of 6 months follow‐up. DSA positivity was examined under two categories, either the lowest level detectable (MFI > 500) or a level presumed to have clinical relevance in our immunogenetics laboratory (MFI > 5000). Of 52 patients, 36 received ABO‐c transplants and 16 received ABO‐i transplants. Compared to ABO‐c recipients, the ABO‐i group showed a consistent but statistically non‐significant finding of less frequent ndDSA positivity (69.4% ABO‐c vs 43.8% ABO‐i with MFI >500, P = 0.122; 41.7% ABO‐c vs 25% ABO‐i with MFI >5000, P = 0.353). Additionally, ABO‐i patients were less likely to have any form of rejection (12.5% vs 47.2%, P = 0.027) or acute cellular rejection (6.3% vs 38.9%, P = 0.021). Our data suggest that infants receiving ABO‐i heart transplants may be less likely to develop ndDSAs or have rejection compared to same age ABO‐c recipients. Larger multicenter studies are needed to confirm results from this single center study.     

Social framework of pediatric heart recipients who have survived more than 15 post‐transplant years: A single‐center experience

To evaluate social development of pediatric heart transplant (tx) recipients who have lived 15 or more years after transplantation. Among 498 pediatric patients, age less than 18 years, who underwent heart transplantation, at a single institution, 337 were performed between 1985 and 1998. We identified all who survived more than 15 years and engaged them in a survey regarding employment, education, marital, and social status. One hundred and eighty‐three recipients (54.3%; 183/337) have survived greater than 15 years; of these, 150 (81.9%) subjects are alive with age ranging from 15.04 from 28 years (median, 23.6 years). Forty‐two patients (23%) are independent, 127 (69%) were living at home, and 14 (8%) have been lost to follow‐up. Ninety‐nine survivors (66%) responded to the survey study. Currently, five recipients are married. Seventy‐four completed high school, 21 are enrolled in high school, and four did not complete high school. Of the 47 recipients who started college, 27 are currently enrolled, 11 graduated, and nine did not finish college. Ninety‐four patients have health insurance, 40 are employed, and 31 receive financial assistance for a disability. The majority of recipients of pediatric heart transplantation are able to reach reasonable academic milestones, achieve social well‐being, and professional independence.     

Diffuse myocardial fibrosis among healthy pediatric heart transplant recipients: Correlation of histology,cardiovascular magnetic resonance,and clinical phenotype

Fibrosis is commonly described in heart allografts lost late after transplantation. CMR‐derived ECV is a validated measure of DMF in native adult hearts that may predict heart failure and mortality. We explored associations of ECV with histologic myocardial fibrosis and clinical features after pediatric heart transplantation. Twenty‐five recipients (7.0±6.3 years at transplant and 10.7±6.5 years post‐transplant) were prospectively recruited for CMR and BNP measurement at the time of surveillance biopsy. All had normal ejection fractions and lacked heart failure symptoms. Fibrosis was quantified on biopsy after picrosirius red staining as CVF. ECV was quantified using contemporaneous hematocrit on basal and mid‐short‐axis slices. ECV was moderately correlated with CVF (r=.47; P=.019). We found no associations of ECV with hemodynamics, ischemic time, time since transplantation, or number of prior biopsies or acute rejections. Compared to healthy non‐transplant controls, there was no significant difference in ECV (25.1±3.0 vs 23.7±2.0%, P=.09). Log‐transformed BNP was correlated with ECV (recipients: r=.46, P=.02; recipients and controls: r=.45, P=.006). These findings suggest ECV quantifies DMF and relates to biological indicators of cardiac function after pediatric heart transplantation.     

Alemtuzumab induction with tacrolimus monotherapy in 25 pediatric renal transplant recipients

ALA induction in transplantation has been shown to reduce the need for maintenance immunosuppression. We report the outcome of 25 pediatric renal transplants between 2007 and 2010 using ALA induction followed by tacrolimus maintenance monotherapy. Patient ages were 1–19 yr (mean 14 ± 4.1 yr). Time of follow‐up was 7–51 months (mean 26 ± 13 months). Tacrolimus monotherapy was maintained in 48% of patients, and glucocorticoids were avoided in 80% of recipients. Mean plasma creatinine and GFR at one yr post‐transplant were 0.88 ± 0.3 mg/dL and 104.4 ± 25 mL/min/1.73m², respectively. One, two, and three‐yr actuarial patient and graft survival rates were 100%. The incidence of early AR (<12 months after transplantation) was 12%, while the incidence of late AR (after 12 months) was 16%. Forty‐four percent of the recipients recovered normal, baseline renal function after an episode of AR, and 44% had persistent renal dysfunction (plasma creatinine 1.0–1.8 mg/dL). One graft was lost four yr after transplantation due to medication non‐compliance. Four (16%) patients developed BK or CMV infection. In our experience, ALA induction with tacrolimus monotherapy resulted in excellent short‐ and mid‐term patient and graft survival in low‐immunologic risk pediatric renal transplant recipients.     

Immune cell function assay in pediatric heart transplant recipients

The ImmuKnow^® ICFA reports ex vivo CD4 lymphocyte activation to quantify immunosuppression. Limited organ and age‐specific data exist for pediatric heart transplant recipients. We sought to examine their normative values and ICFA's association with rejection/infection. A total of 380 ICFAs from 58 heart transplant recipients (6.5/recipient) were studied retrospectively. The median age at the time of their first ICFA was 5.3 yr (IQR 2.4–12.1 yr). ICFA levels during immunologic stability (n = 311) were a median of 305 (IQR: 172–483) and mean of 353 (s.d. ± 224) ng ATP/mL. ICFA levels trended lower with advancing age. ICFA levels during immunologic stability increased over time from transplant after the first six months but were not correlated with calcineurin inhibitor levels or the type used. There is no association between ICFA values during stability and rejection (median 368 ATP ng/mL; IQR 153–527) or infection (median 293 ATP ng/mL; IQR 198–432). In contrast to the manufacturer's suggested ranges, the immunologic stable ranges in pediatric cardiac recipients were very different. ICFA values during immunologic stability are related to time from transplant in pediatric heart recipients. ICFA's ability to discriminate rejection or infection from immunologic stability was not demonstrated.     

New‐onset diabetes after pediatric heart transplantation: A review of the Pediatric Heart Transplant Study

NDT is a well‐defined complication after solid organ transplantation. Little has been published describing the incidence, risk factors, and effect on outcome after pediatric heart transplantation. We performed a retrospective evaluation of pediatric patients from the PHTS registry from 2004 to 2014. Group comparison, associated factors, incidence using Kaplan‐Meier method, and risk factor and outcome analysis for NDT at 1 year post‐transplant. Of the 2185 recipients, 1756 were alive and followed at 1 year. Overall freedom from NDT was 98.9%, 94.7%, and 92.6% at 1, 5, and 10 years, respectively. Patients with NDT were more likely to be black (non‐Hispanic; P = 0.002), older at time of transplant (P < 0.0001), and have a higher BMI percentile at time of transplant (P < 0.0001). Adjusted risk factors for NDT at 1 year were older age at transplant (years; >12 years, OR: 8.8 and 5‐12 years, HR: 8.0), obese BMI percentile at time of transplant (OR: 3.8), and steroid use at 30 days after transplant (OR: 4.7). Though uncommon, NDT occurs with a constant hazard after pediatric heart transplant; it occurs more often in older patients at transplant, those who are of black race, those who are obese, and those who use steroids. Therefore, targeted weight reduction and selective steroid use in at‐risk populations could reduce the incidence of early NDT. Further data are needed to determine the risk imparted by transplantation, factors that predict late‐onset NDT, and whether NDT alters the outcome after transplant.     

The impact of flow PRA on outcome in pediatric heart recipients in modern era: An analysis of the Pediatric Heart Transplant Study database

Data from patients in the Pediatric Heart Transplant Study (PHTS) registry transplanted between 2010 and 2014 were analyzed to determine the association between HLA antibody (PRA) determined by SPA using Luminex or flow cytometry with a positive retrospective cross‐match and the post‐transplant outcomes of acute rejection and graft survival. A total of 1459 of 1596 (91%) recipients had a PRA reported pretransplant; 26% had a PRA > 20%. Patients with a PRA > 20% were more likely to have CHD, prior cardiac surgery, ECMO support at listing, and waited longer for transplantation than patients with a PRA <20%. Patients with higher PRA% determined by SPA were predictive of a positive retrospective cross‐match determined by flow cytometric method (P < .001). A PRA > 50% determined by SPA was independently associated with worse overall graft survival after first month of transplant in both unadjusted and adjusted for all other risk factors. In this large multicenter series of pediatric heart transplant recipients, an elevated PRA determined by SPA remains a significant risk factor in the modern era.     

HLA desensitization with bortezomib in a highly sensitized pediatric patient

The proteasome inhibitor bortezomib has been used with variable success in the treatment of AMR following heart transplant. There is limited experience with this agent as a pretransplant desensitizing therapy. We report a case of successful HLA desensitization with a bortezomib‐based protocol prior to successful heart transplantation. A nine‐yr‐old boy with dilated cardiomyopathy, not initially sensitized to HLA (cPRA of zero), required three days of ECMO, followed by implantation of a Heartmate II LVAD. Within six wk, the patient developed de novo class I IgG and C1q complement‐fixing HLA antibodies with a cPRA of 100%. Two doses of IVIG (2 g/kg) failed to reduce antibody levels, although two courses of a novel desensitization protocol consisting of rituximab (375 mg/m²), bortezomib (1.3 mg/m² × 5 doses), and plasmapheresis reduced his cPRA to 0% and 87% by the C1q and IgG assays, respectively. He underwent heart transplantation nearly two months later. The patient is now >one yr post‐transplant, is free of both AMR and ACR, and has no detectable donor‐specific antibodies by IgG or C1q. Proteasome inhibition with bortezomib and plasmapheresis may be an effective therapy for HLA desensitization pretransplant.     

Ten yr of pediatric heart transplantation: A report from the Pediatric Heart Transplant Study

The PHTS was founded in 1991 as a not‐for‐profit organization dedicated to the advancement of the science and treatment of children during listing for and following heart transplantation. Now, 21 yr later, the PHTS has contributed significantly to the field, most notably in the form of outcomes analyses and risk factor assessment, in addition to amassing the most detailed dataset on pediatric heart transplant recipients worldwide. The purpose of this report is to review the last decade of pediatric patients listed for heart transplantation (January 1, 2000–December 31, 2009) and summarize the changes, trends, outcomes, and lessons learned.     

Effects of an acute,outpatient physiotherapy exercise program following pediatric heart or lung transplantation

This prospective interventional study investigated the impact of a three‐month, ambulatory HA or HB, semi‐individualized, PT‐prescribed exercise program following pediatric HTx or LTx. SMW distance, strength, and flexibility were assessed at start and completion of the program and one yr after enrollment. Subjects received either an HB or HA exercise program three times per week. The cohort demonstrated clinically and statistically significant improvements in SMW distances at three months (425.7 ± 109.4–500.6 ± 93.6 m, p < 0.001) and at one yr (528.5 ± 66.6 m, p = 0.001), although there was no difference between the two groups at any time. Similar improvements were also observed in strength and flexibility measures. Correlates with higher SMW distance at three months and one yr included older age, male gender, and underlying diagnosis other than CHD. Male gender and diagnosis other than CHD were associated with a slower improvement in the SMW distance. This is the first report of institutionally based, outpatient exercise rehabilitation in the recovery following pediatric thoracic transplantation. We found similar improvements to HB interventions up to one yr after surgery. Further study of the role of exercise rehabilitation and long‐term fitness outcomes is needed.     

Low donor‐to‐recipient weight ratio does not negatively impact survival of pediatric heart transplant patients

Tang L, Du W, Delius RE, L’Ecuyer TJ, Zilberman MV. Low donor‐to‐recipient weight ratio does not negatively impact survival of pediatric heart transplant patients.
Pediatr Transplantation 2010: 14:741–745. © 2010 John Wiley & Sons A/S. Abstract: A major limitation to success in pediatric heart transplantation is donor organ shortage. While the use of allografts from donors larger than the recipient is accepted, the use of undersized donor grafts is generally discouraged. Using the UNOS database, we wanted to evaluate whether using smaller donor hearts affects the short‐ and long‐term survival of pediatric heart transplant patients. A retrospective analysis of data entered into the UNOS database from April 1994 to May 2008 was performed. Pediatric heart transplant recipients (ages 0–18 yr) with DRWR <2.0 were identified and divided into two groups: Low‐DRWR (<0.8) and Ideal‐DRWR (0.8–2.0). Patients’ demographics, pretransplant diagnoses, age at transplantation, severity of pretransplant condition, and rate of complications prior to hospital discharge after transplantation were noted. Fisher’s exact, chi‐square, and Wilcoxon rank sum tests were used to compare patients’ baseline characteristics. Kaplan–Meier curves and Cox proportional hazard regression were used to compare patients’ survival and to identify independent risk factors for outcomes. There were 3048 patients (204 with Low‐ and 2844 with Ideal‐DRWR). The Low‐ratio group patients were older (8.3 vs. 6.9 yr; p = 0.001), there was a slight male predominance in the Low‐DRWR group (p = 0.055). The Low‐DRWR group had longer transplant wait time than the Ideal‐DRWR group (97 vs. 85 days; p = 0.04). The groups did not differ in race, primary diagnoses, severity of pretransplant condition (medical urgency status, need for ventilation, inotropic support, ECMO, nitric oxide, or dialysis, the PVR for those with bi‐ventricular anatomy), or post‐transplant complications (length of stay, need for inotropic support, dialysis, and rate of infections). The Low‐DRWR patients had less episodes of acute rejection during the first‐post‐transplant month. Infants with DRWR 0.5–0.59 had lower 30‐day survival rate (p = 0.045). There was no difference in short‐ and long‐term survival between the patients with DRWR 0.6–0.79 and DRWR 0.8–2.0. Use of smaller allografts (DRWR 0.6–0.8) has no negative impact on the short‐ and long‐term survival of pediatric heart transplant patients.     

Child and parental perspectives of multidimensional quality of life outcomes after kidney transplantation

Anthony SJ, Hebert D, Todd L, Korus M, Langlois V, Pool R, Robinson LA, Williams A, Pollock‐BarZiv SM. Child and parental perspectives of multidimensional quality of life outcomes after kidney transplantation.
Pediatr Transplantation 2010:14:249–256. © 2009 John Wiley & Sons A/S. Abstract: Kidney transplantation is an optimal therapy for pediatric patients with end‐stage kidney disease. This pilot study sought to examine multidimensional QOL outcomes after kidney transplant using VAQOL and General Health, the PedsQL 4.0, PedsQL End Stage Renal Disease Module, and Impact on Family Module. Sample included 12 adolescents aged 13–18 yr and their parent; three children aged eight to 12 yr and their parent; and six parents of children aged two to seven yr. All were 73 months post transplant. The median age at transplant was 9.3 yr and median time since transplant was 3.2 yr. VAQOL mean was 7.7/10 (child report) and 7.3/10 (parent report); the mean general health was 7.4/10. High levels of fatigue (≥5/10) were reported in 43%. PedsQL subscale mean values were lower than healthy reference scores. PedsQL Renal Module demonstrated great concern with physical appearance and physical symptoms (thirst and headaches), difficulty with peer and family interaction, and school disruption. Low scores on parental emotional function depict the negative impact of transplant on family functioning. Discordance exists between child and parental reports of QOL. Prospective studies are needed to explore multidimensional QOL to improve long‐term outcomes after pediatric kidney transplant.     

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.     

The effect of MMF dose and trough levels on adverse effects in pediatric heart transplant recipients

Limited pharmacokinetic and safety data exist for MMF in pediatric HTR. Previously targeted MPA‐TL are 1.5–3.0 μg/mL. The objective of this study was to assess the outcomes targeting MPA‐TL of 0.8–2.0 μg/mL in pediatric HTR. MPA‐TL were retrospectively collected 2–12 months post‐transplant. Acute rejection, infection, leukopenia, and GI complaints were then correlated with MPA‐TL. A total of 355 MPA‐TL from 22 HTR were included. Median age was 2.5 yr. Primary indication for transplant was dilated cardiomyopathy (64%). Mean MPA‐TL was 1.7 ± 0.9 μg/mL. African American patients received significantly higher doses (702 ± 235 mg/m²) compared with other races (p = 0.035). Leukopenia was less common in patients with SUB MPA vs. others (p = 0.01). MMF was discontinued for GI complaints in one patient and leukopenia in two patients. One SUB patient had acute rejection, and one SUP patient had infection. One‐yr survival was 100%. Targeting a lower range for MPA‐TL was not associated with significant rejection or infection. Despite lower MPA‐TL, MMF was discontinued in 3/22 patients for adverse effects.