Mary Zamberlan

Outcomes of Pediatric Patients With Hypertrophic Cardiomyopathy Listed for Transplant

BACKGROUND The course of pediatric hypertrophic cardiomyopathy (HCM) is variable, and the indications for heart transplantation (HTx) are ill defined. This study investigated outcomes and risk factors for adverse outcomes after listing for HTx. METHODS A multicenter, event-driven data registry of patients aged < 18 years listed for HTx between January 1993 and December 2007 was used. RESULTS During the study period, 3,147 children were listed for HTx (mean age, 7.6 +/- 0.8 years). Of l,320 with CM at listing, 77 (6%) had HCM (61% boys; 79% white); 59% were United Network of Organ Sharing (UNOS) status I, 30% were receiving inotropes, 27% were ventilated, and 8% required extracorporeal membrane oxygenation. Arrhythmia had occurred in 27%, and 14% had failure to thrive. Within 1 year, 65% underwent HTx. Overall, 25 patients died after listing: 11 (14%) while waiting and 14 of 49 (29%) after HTx. Pre-HTx survival was lower for those listed at age < 1 year (p = 0.0005). Risk factors for death after listing included UNOS status 1 (p = 0.01) and younger age (relative risk, 2.3; p = 0.001). Late (10-year) survival after HTx for HCM patients was 47% vs 63% for non-CM patients within the database. CONCLUSIONS Children with HCM listed for HTx age < 1 year and UNOS status 1 have the highest mortality awaiting HTx. A more rigorous identification of additional risk factors should be performed to better define timing of listing and which patient sub-group may derive optimal benefit from HTx.

Infection and malignancy after pediatric heart transplantation: The role of induction therapy

BACKGROUND Variable rates of malignancy and early infection have previously been reported in heart transplant (HTx) recipients who received induction therapy. This study hypothesized that induced pediatric patients would have an increased risk of these events compared with non-induced patients. METHODS Data from a prospective, multicenter event-driven registry of outcomes after HTx listing in patients aged < 18 years was used to analyze risks of infection and malignancy and their association with induction between January 1993 and December 2007. RESULTS Of 2,374 patients, 1,258 (53%) received induction and more frequently from 1999 to 2008 compared with 1993 to 1998 (70.8% vs 57.5%, p < 0.001). At HTx, induced patients were more likely to have congenital heart disease (56.9% vs 48.1%, p < 0.001) but no more likely to be positive for Epstein-Barr virus (50.3% vs 51.4%, p = 0.67). Post-transplant lymphoproliferative disease (PTLD) was the most common malignancy (n = 92) within 5 years of HTx. Patients who received induction had a lower risk for PTLD (hazard ratio [HR], 0.5; 95% confidence interval [CI], 0.3-0.84; p = 0.009) and early fungal infections (HR, 0.60; 91% CI, 0.40-0.91; p = 0.016). Among induction agents used, OKT3 was associated with lowest freedom from PTLD and fungal/cytomegalovirus infection. CONCLUSIONS Induction use has increased since 1999 and has not been associated with an increased risk of malignancy (predominantly PTLD) or overall infection. Because these adverse events occurred with higher rates in non-induced patients, it is likely that induction alone is not the primary risk determinant for PTLD and infection.

HLA Sensitization in Pediatric Pre-transplant Cardiac Patients Supported by Mechanical Assist Devices: the Utility of Luminex

BACKGROUND HLA sensitization rates in children on extracorporeal membrane oxygenation (ECMO) or ventricular assist devices (VADs) are unknown. In addition, panel-reactive antibody (PRA) assessment is increasingly being performed by Luminex, whose role in comparison to other conventional methods is unclear. We investigated HLA sensitization of mechanically supported children using established PRA methods and then retested stored serum using Luminex to assess its impact on initial PRA results and post-heart transplant (post-HTx) outcomes. METHODS Data on 22 pre-HTx ECMO or VAD patients (0 to 18 years of age) included: age; duration of mechanical support; use of homograft; red cell transfusion volume; PRAs; and outcome. Comparative data were collected from 10 non-supported, age-matched controls. RESULTS Median age of the 13 ECMO and 9 VAD patients was 1.4 and 192 months (p < 0.001), respectively. Six (27%) device patients and 4 (40%) controls had baseline PRAs >10% (p = 0.7). No ECMO but 6 VAD patients were sensitized after 50 +/- 51 days of support (p = 0.02). Compared with ECMO, VAD patients had higher Class I PRAs according to enzyme-linked immunoassay (p = 0.03). VAD patients had higher final vs initial PRAs for Class I (p = 0.05) and II (p = 0.04) antigens. HLA sensitization was independent of transfusion volume. Only complement-dependent cytotoxicity (CDC) Class I PRAs were different from their respective Luminex values (p = 0.03). Four HTx patients with initially low PRAs but elevated post hoc Luminex assays had no rejection at 3.8 +/- 1.6 years post-HTx. CONCLUSIONS Infants supported with ECMO are at low risk for HLA sensitization. Because it provides full antibody specificity disclosure, Luminex complements more conventional PRA assays by quantitatively identifying potential donor-specific antibodies, which should facilitate the virtual crossmatch process, thereby minimizing post-HTx humoral rejection risk.

Lack of Correlation Between MMF Dose and MPA Level in Pediatric and Young Adult Cardiac Transplant Patients: Does the MPA Level Matter?

To determine the correlation between mycophenolate mofetil (MMF) dose and mycophenolic acid (MPA) level as well as its impact on rejection among young cardiac transplant recipients (OHT), trough concentrations of MPA and its metabolite, mycophenolic acid glucuronide (MPAG), were measured following MMF doses of 1200 mg/m2/d (max 3000 mg/d). Corresponding endomyocardial biopsy (EMB) grades and calcineurin inhibitor levels were recorded with simultaneous MPA/MPAG levels. Correlation coefficients were derived between MMF dose and MPA/MPAG levels. Contingency analysis evaluated the relation between MPA level and EMB score.

Predicting Graft Loss by 1 Year in Pediatric Heart Transplantation Candidates An Analysis of the Pediatric Heart Transplant Study Database

Background— Pediatric data on the impact of pre–heart transplantation (HTx) risk factors on early post-HTx outcomes remain inconclusive. Thus, among patients with previous congenital heart disease or cardiomyopathy, disease-specific risk models for graft loss were developed with the use pre-HTx recipient and donor characteristics. Methods and Results— Patients enrolled in the Pediatric Heart Transplant Study (PHTS) from 1996 to 2006 were stratified by pre-HTx diagnosis into cardiomyopathy and congenital heart disease cohorts. Logistic regression identified independent, pre-HTx risk factors. Risk models were constructed for 1-year post-HTx graft loss. Donor factors were added for model refinement. The models were validated with the use of patients transplanted from 2007 to 2009. Risk factors for graft loss were identified in patients with cardiomyopathy (n=896) and congenital heart disease (n=965). For cardiomyopathy, independent risk factors were earlier year of transplantation, nonwhite race, female sex, diagnosis other than dilated cardiomyopathy, higher blood urea nitrogen, and panel reactive antibody >10%. The recipient characteristic risk model had good accuracy in the validation cohort, with predicted versus actual survival of 97.5% versus 95.3% (C statistic, 0.73). For patients with congenital heart disease, independent risk factors were nonwhite race, history of Fontan, ventilator dependence, higher blood urea nitrogen, panel reactive antibody >10%, and lower body surface area. The risk model was less accurate, with 86.6% predicted versus 92.4% actual survival, in the validation cohort (C statistic, 0.63). Donor characteristics did not enhance model precision. Conclusions— Risk factors for 1-year post-HTx graft loss differ on the basis of pre-HTx cardiac diagnosis. Modeling effectively stratifies the risk of graft loss in patients with cardiomyopathy and may be an adjunctive tool in allocation policies and center performance metrics. # CLINICAL PERSPECTIVE {#article-title-28}Background— Pediatric data on the impact of pre–heart transplantation (HTx) risk factors on early post-HTx outcomes remain inconclusive. Thus, among patients with previous congenital heart disease or cardiomyopathy, disease-specific risk models for graft loss were developed with the use pre-HTx recipient and donor characteristics. Methods and Results— Patients enrolled in the Pediatric Heart Transplant Study (PHTS) from 1996 to 2006 were stratified by pre-HTx diagnosis into cardiomyopathy and congenital heart disease cohorts. Logistic regression identified independent, pre-HTx risk factors. Risk models were constructed for 1-year post-HTx graft loss. Donor factors were added for model refinement. The models were validated with the use of patients transplanted from 2007 to 2009. Risk factors for graft loss were identified in patients with cardiomyopathy (n=896) and congenital heart disease (n=965). For cardiomyopathy, independent risk factors were earlier year of transplantation, nonwhite race, female sex, diagnosis other than dilated cardiomyopathy, higher blood urea nitrogen, and panel reactive antibody >10%. The recipient characteristic risk model had good accuracy in the validation cohort, with predicted versus actual survival of 97.5% versus 95.3% (C statistic, 0.73). For patients with congenital heart disease, independent risk factors were nonwhite race, history of Fontan, ventilator dependence, higher blood urea nitrogen, panel reactive antibody >10%, and lower body surface area. The risk model was less accurate, with 86.6% predicted versus 92.4% actual survival, in the validation cohort (C statistic, 0.63). Donor characteristics did not enhance model precision. Conclusions— Risk factors for 1-year post-HTx graft loss differ on the basis of pre-HTx cardiac diagnosis. Modeling effectively stratifies the risk of graft loss in patients with cardiomyopathy and may be an adjunctive tool in allocation policies and center performance metrics.

Fontan-associated protein-losing enteropathy and heart transplant: A Pediatric Heart Transplant Study analysis

BACKGROUND Post-Fontan protein-losing enteropathy (PLE) is associated with significant morbidity and mortality. Although heart transplantation (HTx) can be curative, PLE may increase the risk of morbidity before and after HTx. This study analyzed the influence of PLE influence on waiting list and post-HTx outcomes in a pediatric cohort. METHODS Fontan patients listed for HTx and enrolled in the Pediatric Heart Transplant Study from 1999 to 2012 were stratified by a diagnosis of PLE, and the association of PLE with waiting list and post-HTx mortality, rejection, and infection was analyzed. RESULTS Compared with non-PLE Fontan patients (n = 260), PLE patients listed for HTx (n = 96) were older (11.9 years vs 7.6 years; p = 0.003), had a larger body surface area (1.1 m(2) vs 0.9 m(2); p = 0.0001), had lower serum bilirubin (0.5 vs 0.9 mg/dl; p = 0.01), lower B-type natriuretic peptide (59 vs 227 pg/ml; p = 0.006), and were less likely to be on a ventilator (3% vs 13%; p = 0.006). PLE patients had lower waiting list mortality than non-PLE Fontan patients (p < 0.0001). There were no intergroup differences for post-HTx survival or times to the first infection or rejection. PLE was not independently associated with increased post-HTx mortality at any time point. CONCLUSIONS In this multicenter cohort, the diagnosis of PLE alone was not associated with increased waiting list mortality or post-HTx morbidity or mortality. Given the limitations of our data, this analysis suggests that PLE patients in the pediatric age group have outcomes similar to their non-PLE counterparts. Additional multicenter studies of PLE patients with targeted collection of PLE-specific information will be necessary to fully delineate the risks conferred by PLE for HTx.

Association of Pediatric Heart Transplant Coronary Vasculopathy with Abnormal Hemodynamic Measures

OBJECTIVE Transplant coronary artery disease (TCAD) is the limiting factor to long-term cardiac allograft survival; however, presymptomatic diagnosis remains challenging. To that concern, we evaluated the association of abnormal catheter-derived filling pressures with TCAD in pediatric heart transplant (HTx) recipients. DESIGN, PATIENTS, OUTCOME MEASURES: Data from 52 presymptomatic pediatric HTx patients were analyzed. Catheter-derived right ventricular end-diastolic pressure (RVEDP) and pulmonary capillary wedge pressure (PCWP) were recorded. Biopsies were collected to verify the absence of rejection. RESULTS TCAD was diagnosed an average of 8.3 years post-HTx in 20 (38%) patients, six of whom died and four of whom underwent retransplantation. Catheter-derived pressure measurements showed that RVEDP was elevated in TCAD compared with non-TCAD patients (9.5 ± 6.0 vs. 5.4 ± 4.7; P= .005), as was the PCWP (12.9 ± 5.7 vs. 9.1 ± 5.7; P= .012). Results from logistic regression analysis showed RVEDP > 10 mm Hg or PCWP > 12 mm Hg was associated with TCAD (OR = 5.2; P= .010). CONCLUSIONS In this series, elevated ventricular filling pressures measured during routine surveillance catheterizations were associated with angiographic TCAD. Recognizing the association between elevated RVEDP/PCWP and TCAD may prompt earlier diagnosis and treatment of this potentially lethal process.

Outcomes of third heart transplants in pediatric and young adult patients: Analysis of the United Network for Organ Sharing database

BACKGROUND Repeat heart transplantation (re-HTx) is standard practice in many pediatric centers. There are limited data available on outcomes of third HTx after failure of a second graft. We sought to compare outcomes of third HTx in pediatric and young adult patients with outcomes of second HTx in comparable recipients. METHODS All recipients of a third HTx in whom the primary HTx occurred before 21 years of age were identified in the United Network for Organ Sharing database (1985 to 2011) and matched 1:3 with a control group of second HTx patients by age, era and re-HTx indication. Outcomes including survival, rejection and cardiac allograft vasculopathy (CAV) were compared between groups. RESULTS There was no difference between third HTx patients (n = 27) and control second HTx patients (n = 79) with respect to survival (76% vs 80% at 1 year, 62% vs 58% at 5 years and 53% vs 34% at 10 years, p = 0.75), early (<1 year from HTx) rejection (33.3% vs 44.3%, p = 0.32) or CAV (14.8% vs 30.4%, p = 0.11). Factors associated with non-survival in third HTx patients included mechanical ventilation at listing or HTx, extracorporeal membrane oxygenation support at listing or HTx, and elevated serum bilirubin at HTx. CONCLUSIONS Outcomes among recipients of a third HTx are similar to those with a second HTx in matched patients, with no difference in short- or long-term survival and comparable rates of early rejection and CAV. Although the occurrence of a third HTx remains relatively rare in the USA, consideration of a third HTx appears reasonable in appropriately selected patients.

Psychosocial functioning in pediatric heart transplant recipients and their families

Across pediatric organ transplant populations, patient and family psychosocial functioning is associated with important health‐related outcomes. Research has suggested that pediatric heart transplant recipients and their families are at increased risk for adverse psychosocial outcomes; however, recent investigation of psychosocial functioning in this population is lacking. This study aimed to provide a contemporary characterization of psychosocial functioning in pediatric heart transplant recipients and their families. Associations between psychosocial function, demographic variables, and transplant‐related variables were investigated. Fifty‐six parents/guardians of pediatric heart transplant recipients completed a comprehensive psychosocial screening measure during transplant follow‐up clinic visits. Descriptive statistics, correlational analyses, and independent samples t tests were performed. Forty percent of pediatric heart transplant recipients and their families endorsed clinically meaningful levels of total psychosocial risk. One‐third of patients presented with clinically significant psychological problems per parent report. Psychosocial risk was unassociated with demographic or transplant‐related factors. Despite notable improvements in the survival of pediatric heart transplant recipients over the past decade, patients and families present with sustained psychosocial risks well beyond the immediate post‐transplant period, necessitating mental health intervention to mitigate adverse impact on health‐related outcomes.

Predicting Graft Loss by 1-Year in Pediatric Heart Transplant Candidates: An Analysis of the PHTS Database

Background— Pediatric data on the impact of pre–heart transplantation (HTx) risk factors on early post-HTx outcomes remain inconclusive. Thus, among patients with previous congenital heart disease or cardiomyopathy, disease-specific risk models for graft loss were developed with the use pre-HTx recipient and donor characteristics. Methods and Results— Patients enrolled in the Pediatric Heart Transplant Study (PHTS) from 1996 to 2006 were stratified by pre-HTx diagnosis into cardiomyopathy and congenital heart disease cohorts. Logistic regression identified independent, pre-HTx risk factors. Risk models were constructed for 1-year post-HTx graft loss. Donor factors were added for model refinement. The models were validated with the use of patients transplanted from 2007 to 2009. Risk factors for graft loss were identified in patients with cardiomyopathy (n=896) and congenital heart disease (n=965). For cardiomyopathy, independent risk factors were earlier year of transplantation, nonwhite race, female sex, diagnosis other than dilated cardiomyopathy, higher blood urea nitrogen, and panel reactive antibody >10%. The recipient characteristic risk model had good accuracy in the validation cohort, with predicted versus actual survival of 97.5% versus 95.3% (C statistic, 0.73). For patients with congenital heart disease, independent risk factors were nonwhite race, history of Fontan, ventilator dependence, higher blood urea nitrogen, panel reactive antibody >10%, and lower body surface area. The risk model was less accurate, with 86.6% predicted versus 92.4% actual survival, in the validation cohort (C statistic, 0.63). Donor characteristics did not enhance model precision. Conclusions— Risk factors for 1-year post-HTx graft loss differ on the basis of pre-HTx cardiac diagnosis. Modeling effectively stratifies the risk of graft loss in patients with cardiomyopathy and may be an adjunctive tool in allocation policies and center performance metrics. # CLINICAL PERSPECTIVE {#article-title-28}Background— Pediatric data on the impact of pre–heart transplantation (HTx) risk factors on early post-HTx outcomes remain inconclusive. Thus, among patients with previous congenital heart disease or cardiomyopathy, disease-specific risk models for graft loss were developed with the use pre-HTx recipient and donor characteristics. Methods and Results— Patients enrolled in the Pediatric Heart Transplant Study (PHTS) from 1996 to 2006 were stratified by pre-HTx diagnosis into cardiomyopathy and congenital heart disease cohorts. Logistic regression identified independent, pre-HTx risk factors. Risk models were constructed for 1-year post-HTx graft loss. Donor factors were added for model refinement. The models were validated with the use of patients transplanted from 2007 to 2009. Risk factors for graft loss were identified in patients with cardiomyopathy (n=896) and congenital heart disease (n=965). For cardiomyopathy, independent risk factors were earlier year of transplantation, nonwhite race, female sex, diagnosis other than dilated cardiomyopathy, higher blood urea nitrogen, and panel reactive antibody >10%. The recipient characteristic risk model had good accuracy in the validation cohort, with predicted versus actual survival of 97.5% versus 95.3% (C statistic, 0.73). For patients with congenital heart disease, independent risk factors were nonwhite race, history of Fontan, ventilator dependence, higher blood urea nitrogen, panel reactive antibody >10%, and lower body surface area. The risk model was less accurate, with 86.6% predicted versus 92.4% actual survival, in the validation cohort (C statistic, 0.63). Donor characteristics did not enhance model precision. Conclusions— Risk factors for 1-year post-HTx graft loss differ on the basis of pre-HTx cardiac diagnosis. Modeling effectively stratifies the risk of graft loss in patients with cardiomyopathy and may be an adjunctive tool in allocation policies and center performance metrics.