Search

Background: Pediatric heart transplantation has now been successfully performed for more than 20 years. As survival rates have improved, more attention is now focused on long-term outcomes. Methods: This report reviews the literature on developmental outcomes after pediatric heart transplantation. Results: Pediatric patients undergoing heart transplantation generally can be expected to have developmental outcomes in the low-normal range, consistent with outcomes seen in other children with complex congenital heart disease requiring surgical intervention. When these children reach school age, or return to school, most can be expected to function reasonably well in mainstream school settings. A significant minority will require additional educational assistance. Approximately 10% will have significant neurologic impairment. In school, particular attention should be paid to evaluating the child for deficits in arithmetic and verbal skills. Performance may be better than predicted from IQ testing. Behavioral issues are common, with depression, concerns about social competence, and attention difficulties most frequently endorsed. This may pre-date transplantation in those who undergo transplantation during childhood and may improve with time. Parents more often report problem behaviors than teachers. Family resources and family coping skills are also strongly correlated with the child''s emotions and coping skills. Conclusion: The pediatric heart transplant recipient''s ability to transition from childhood into a happy and productive adult life can be significantly affected by his or her cognitive abilities, learning experiences, sense of self, and emotions. Attention to these factors is an important part of caring for these children. [Copyright &y& Elsevier]

Pediatric heart transplant recipients have been expected to be at higher risk of adverse events from developing COVID-19 infection. COVID-19 RNA PCR and antibody testing has been performed in our cohort of patients since March 15, 2020 and outcomes were reviewed. COVID-19 infection in our population of pediatric heart transplant recipients is common (21%), despite recommendations to avoid contact with others. Asymptomatic COVID-19 infection is common as well (55%). Despite the frequency of infection, COVID-19 is well tolerated in this population (5% admission from home; 0% mortality). A suppressed immune system does not significantly inhibit an antibody response in pediatric heart transplant recipients (>70% antibody seroconversion) and appears to persist, similar to those without transplantation (>90 days). Routine testing for COVID-19 via PCR and antibody testing enhances the ability to detect COVID-19 infection in asymptomatic patients and may help reduce unintended transmission to more susceptible individuals. [ABSTRACT FROM AUTHOR]

Background: Few data describe exercise performance after cardiac transplantation during infancy. The aim of this study was to compare the cardiorespiratory response to exercise in healthy subjects with that of subjects who had undergone heart transplantation during infancy to treat hypoplastic left heart syndrome.Methods: Subjects (24 heart transplant recipients and 25 healthy controls) exercised on a treadmill using pediatric ramp protocols. We measured heart rate (HR), blood pressure, and metabolic data. Median age at transplantation was 20 days (range, 4 to 97 days). Age of recipients at exercise testing was 9.7 ± 2.3 years and in healthy subjects was 10.5 ± 1.4 years (p = not significant [NS]).Results: Exercise duration was similar in both groups (10.3 ± 2.0 minutes in recipients vs 11.1 ± 1.5 minutes in healthy subjects, (p = NS). Heart rate at rest was greater in recipients (94 ± 15 beats per minute [bpm] vs 85 ± 11 bpm, p = 0.02). Peak HR also was less in the recipient group (158 ± 15 bpm vs 189 ± 12 bpm, p < 0.001). Peak oxygen consumption was 14% less in the recipients (32.3 ± 5.6 ml/kg/min vs 36.8 ± 5.5 ml/kg/min, p < 0.01). Ventilatory anaerobic threshold was decreased in recipients, 27.6 ± 9.6 vs 32.8 ± 6.0, p < 0.05. Respiratory exchange ratio at peak exercise was equal in both groups (1.06 ± 0.06 vs 1.06 ± 0.08). Oxygen pulse index did not differ significantly, 5.5 ± 1.1 ml/beat/m2 in recipients and 6.1 ± 1.7 ml/beat/m2 in healthy subjects (p = NS).Conclusions: Overall, children who undergo cardiac transplantation in infancy have exercise capacities within the normal range. These recipients have a decreased heart rate reserve that may account for the differences in peak oxygen consumption when compared with healthy subjects. [Copyright &y& Elsevier]

Background Proliferation signal inhibitors, such as sirolimus, are increasingly used in solid-organ transplantation. However, limited data exist on sirolimus-treated pediatric patients. We aimed to describe sirolimus use in pediatric heart transplant patients and test the hypothesis that sirolimus use is associated with improved outcomes. Methods A retrospective review and propensity-matched analysis of the Pediatric Heart Transplant Study database was performed on patients undergoing primary heart transplantation from 2004 to 2013 with at least 1 year of follow-up comparing patients treated vs not treated with sirolimus at 1 year after transplant. The primary outcome of interest was patient survival, with secondary outcomes including cardiac allograft vasculopathy, rejection, malignancy, and renal insufficiency. Results Between 2004 and 2013, 2,531 patients underwent transplantation. At least 1 year of follow-up was available for 2,080 patients, of whom 144 (7%) were on sirolimus at 1 year post-transplant. Sirolimus-treated and non-treated patients had similar survival in the overall cohorts and in the propensity-matched analysis. The secondary outcomes measures were also similar, including a composite end point of all outcome measures. There was a trend toward increased time to cardiac allograft vasculopathy ( p = 0.09) and decreased time to infection ( p = 0.05) among sirolimus-treated patients in the overall cohort ( p = 0.19) but not in the propensity-matched cohort ( p = 0.17). Conclusions Sirolimus was used in less than 10% of patients at 1 year post-transplant. Overall outcomes of sirolimus treated and non-treated patients were similar with respect to survival and major transplant adverse events. Further study of sirolimus in pediatric heart transplant patients is needed. [ABSTRACT FROM AUTHOR]

Background: Intentional blood group (BG)-incompatible (ABOi) heart transplantation in childhood is emerging in many centers. Safety limits remain undetermined. In this multicenter study we have compiled experience on clinical and immunologic boundaries. Methods: Data from six centers in Europe and North America on ABOi transplantation were collected in a standardized survey. Results: Fifty-eight ABOi transplants were performed in 57 patients. Median age at transplant was 6.8 months (0.03 to 90 months); post-transplant follow-up was 37.7 months (0.46 to 117 months), accumulating 188 patient-years. Forty-seven percent of the patients received pretransplant mechanical circulatory support. Donors were either blood group A (n = 25), B (n = 18) or AB (n = 15). The median peak antibody titer to the donor BG pretransplant was 1:8 (0 to 1:64) for anti-A and 1:4 (0 to 1:32) for anti-B. Titers against the donor BG were lower post- than pretransplant in B recipients (p = 0.02), whereas third-party antibodies in BG O recipients developed normally post-transplant. Induction immunosuppression included anti-thymocyte globulin (61%), basiliximab (32%) or none (7%). All patients received calcineurin inhibitors, including 62% with mycophenolate mofetil, 10% with azathioprine, 2% with everolimus and 24% with steroids. There were 4 episodes of cellular rejection (Grade≥2R) and 7 antibody-mediated rejections. Five patients underwent antibody removal post-transplant. One patient developed severe graft vasculopathy. Freedom from death or retransplantation was 100%/96%/69% at 1/5/10 years. No graft loss was attributed to BG antibodies. Conclusions: Successful ABOi heart transplantation can be performed at an older age and with higher isohemagglutinin titers than initially assumed and using similar immunosuppressive regimens as for ABO-compatible transplants. Rejection and graft vasculopathy are rare. Persistently low titers of antibodies to the donor BG post-transplant suggest elements of tolerance and/or accommodation. [Copyright &y& Elsevier]

Background: Common genetic variations influence rejection, infection, drug metabolism, and side effect profiles after pediatric heart transplantation. Reports in adults suggest that genetic background may influence post-transplant renal function. In this multicenter study, we investigated the association of genetic polymorphisms (GPs) in a panel of candidate genes on renal function in 453 pediatric heart transplant recipients. Methods: We performed genotyping for functional GPs in 19 candidate genes. Renal function was determined annually after transplantation by calculation of the estimated glomerular filtration rate (eGFR). Mixed-effects and Cox proportional hazard models were used to assess recipient characteristics and the effect of GPs on longitudinal eGFR and time to eGFR < 60 mL/min/1.73m2. Results: Mean age at transplantation was 6.2 ± 6.1 years. Mean follow-up was 5.1 ± 2.5 years. Older age at transplant and black race were independently associated with post-transplant renal dysfunction. Univariate analyses showed FASL (C-843T) T allele (p = 0.014) and HO-1 (A326G) G allele (p = 0.0017) were associated with decreased renal function. After adjusting for age and race, these associations were attenuated (FASL, p = 0.075; HO-1, p = 0.053). We found no associations of other GPs with post-transplant renal function, including GPs in TGFβ1, CYP3A5, ABCB1, and ACE. Conclusions: In this multicenter, large, sample of pediatric heart transplant recipients, we found no strong associations between GPs in 19 candidate genes and post-transplant renal function. Our findings contradict reported associations of CYP3A5 and TGFβ1 with renal function and suggest that genotyping for these GPs will not facilitate individualized immunosuppression for the purpose of protecting renal function after pediatric heart transplantation. [Copyright &y& Elsevier]

Background: Late (occurring >1 year) rejection (LR) has been shown to increase mortality and morbidity after pediatric heart transplantation (HTx). The incidence of rejection has decreased in the first year after pediatric HTx in the current era. We hypothesized a similar phenomenon has occurred with LR. Methods: The Pediatric Heart Transplant Study database was used to analyze the effects of era (1993 to 1998 vs 1999 to 2007) and other factors on the prevalence of LR and its relationship to mortality, moderate–severe coronary vasculopathy (CAV) and retransplantation. Results: Freedom from first LR (59% vs 69% 5-year post-HTx, p < 0.001) and recurrent LR (p < 0.001) was significantly lower in the current vs earlier era. LR was significantly (p < 0.001) associated with early rejection (ER; rejection <1 year post-HTx) in both eras. Independent risk factors for LR were: earlier era (hazard ratio [HR] 1.47, 95% confidence interval [CI] 1.25 to 1.73, p < 0.001); non-white race (HR 1.41; 95% CI 1.19 to 1.67, p < 0.001); older recipient age (HR 1.05, 95% CI 1.03 to 1.06, p < 0.001); recipient Status 2 at transplant (HR 1.21, 95% CI 1.01 to 1.45, p = 0.037); and male donor (HR 1.17; 95% CI 1.0 to 1.37, p = 0.055). Late rejectors had a similar higher risk of mortality (odds ratio [OR] 4.20, 95% CI 3.04 to 5.81, p < 0.001) and incidence of moderate–severe CAV or retransplantation (OR 2.63, 95% CI 1.78 to 3.90, p < 0.001) in both eras. Conclusions: LR has decreased in the recent era in pediatric HTx recipients. Its effect on mortality and the development of CAV has not changed over time, suggesting an ongoing need for improved primary prevention strategies. [Copyright &y& Elsevier]

Background: Late infections are common causes of morbidity and mortality after pediatric heart transplantation. In this multicenter study from 6 centers, we investigated the association between genetic polymorphisms (GPs) in immune response genes and late post-transplantation infections in 524 patients. Methods: Late infection was defined as a clinical infectious process occurring >60 days after transplantation and requiring hospitalization, intravenous antimicrobial therapy, or a life-threatening infection requiring oral therapy. All patients provided a blood sample for GP analyses of 18 GPs in cytokine, growth factor, and effector molecule genes by single specific primer-polymerase chain reaction and/or sequencing. Significant associations in univariable analyses were tested in multivariable Cox regression models. Results: Late infection was common, with 48.7% of patients experiencing ≥1 late infection, 25.2% had ≥1 late bacterial infection, and 30.5% had ≥1 late viral infection. Older age at transplantation was a protective factor for late infection, both bacterial and viral (hazard ratio [HR] 0.89–0.92 per 1-year age increase, p < 0.001). Adjusting for age, race, and transplant etiology, late bacterial infection was associated with HMOX1 A+326G AG and GG genotypes (HR, 2.41, 95% confidence interval [CI] 1.35–4.30; p = 0.003) and GZMB A-295G AA genotype (HR, 1.47; 95% CI; 1.03–2.1; p = 0.036). Late viral infection was associated with FAS A-670G GG genotype (HR, 1.42; 95% CI, 1.00–2.00; p = 0.050) in the adjusted model and with CTLA4 A+49G AA and AG genotypes (HR, 1.49; 95% CI, 1.02–2.19; p = 0.041) in univariable analysis. Conclusion: We found an association between late bacterial infection and GP of HMOX1, which may control macrophage activation. A weaker association was also found between late viral infection and GP of CTLA4, a regulator of T-cell activation. This represents progress toward understanding the clinical and genetic risk factors of outcomes after transplantation. [Copyright &y& Elsevier]

Background: As infant and pediatric heart transplantation becomes more common, there is a growing need to better understand the causes of failure or death, if we are to continue to improve the outcome in these children. Methods: A multidisciplinary team reviewed all deaths occurring in the cohort of infants and children transplanted during the first 20 years of the Loma Linda Pediatric Heart Transplant program, with 2 additional years of follow-up beyond the 20-year accrual period, and classified them as to cause. Results: There were 169 deaths among 421 recipients, with a median follow-up of 9.7 years. Autopsy was performed in 128 cases. The causes of death, in decreasing order of frequency, included acute rejection (26.0%), infection (16.0%), cardiac allograft vasculopathy (CAV) (14.2%), technical issues (8.3%), acute graft dysfunction (6.5%), neoplasm (7.1%), chronic graft dysfunction (4.7%) and miscellaneous factors (10.1%), and in twelve deaths (7.1%) the cause was unclassified. Acute graft dysfunction and technical issues accounted for nearly two-thirds of the deaths in the first 30 days after transplant, while acute rejection resulted in the largest number of deaths after the first year (30.4%), with CAV a close second (23.5%). Conclusions: Acute graft dysfunction and technical issues were the most frequent cause of early death. Late deaths were most often due to acute rejection and CAV, which differs somewhat from the experience reported in adults. Acute rejection was the single most important cause of late mortality, and resulted in a significant number of late sudden and unexpected deaths. [Copyright &y& Elsevier]

Background: An increasing number of children are being referred for cardiac transplantation after (1) failing conventional corrective or palliative surgical reconstruction, (2) after stabilization with mechanical circulatory support devices, and (3) when primary graft failure or advanced cardiac allograft vasculopathy are established. Methods: The records of 417 infants and children (age range, 0–18 years) who underwent cardiac transplantation from November 1985 through December 2005 at Loma Linda University Children''s Hospital were retrospectively reviewed. The pre-transplantation diagnosis was used to divide patients into 3 groups: primary cardiomyopathy (CM), 103; hypoplastic left heart syndrome (HLHS), 154; and other complex congenital heart disease (CCHD), 160. These groups were compared and analyzed for differences in early and late morbidity and mortality. Results: Operative mortality was significantly lower in the CM group compared with the HLHS (p < 0.02;) and CCHD groups (p < 0.01). Long-term actuarial recipient survival, however, was similar for all groups. The 15-year actuarial survival was 59% for the CM Group, 57% for the HLHS Group, and 50% for the CCHD Group. Actuarial survival after retransplantation is not statistically different from that with primary cardiac transplantation. Conclusion: Although peri-operative survival was lower in infants and children with HLHS and CCHD compared with those with CM, long-term survival has been the same for all groups. Late survival after retransplantation was not statistically different than among those with primary cardiac transplantation. [Copyright &y& Elsevier]

Background: There are few published data regarding the long-term outcome of “large” cardiac allografts in children. This study examines the effect of cardiac graft oversizing on the survival of pediatric patients with congenital heart disease (CHD).Methods: Two hundred ninety-one children, age 1 day to 17 years (median 50 days), with CHD underwent primary cardiac transplantation between 1985 and 2002. Patients were analyzed according to donor-recipient weight ratio (D-R): Group (Gp) I (n = 252) with D-R <2.5 (range 0.59 to 2.49, median 1.4), and Gp II (n = 39) with D-R ≥2.5 (range 2.5 to 4.65, median 2.78). CHD diagnoses included hypoplastic left heart syndrome (138 in Gp I, 13 in Gp II), single ventricle (29 in Gp I, 1 in Gp II) and other (85 in Gp I, 13 in Gp II). Patients with cardiomyopathy were excluded. Pre-transplant cardiac palliation was performed in 36% of Gp I and 15% of Gp II patients. The average graft ischemic times (minutes) were 266 ± 7.5 and 283 ± 18.9 for Gp I and Gp II, respectively (p < 0.2).Results: The operative mortality for Gp I was 10.3% and 10.2% for Gp II (p < 0.99). There was no significant difference between the 2 groups in length of hospital stay (p < 0.15) or duration of ventilator support (p < 0.6) post-transplantation. However, the incidence of open chest was higher (p < 0.003) in Gp II (28%) compared with Gp I (8%). The survival rates for Gp I and Gp II were: 82 ± 2.4% vs 84 ± 5.7% at 1 year; 71 ± 2.9% vs 72 ± 7.2% at 5 years; and 63 ± 3.2% vs 65% ± 7.4 at 10 years.Conclusions: Post-transplant morbidity and short- and long-term survival of pediatric recipients with CHD are not adversely influenced by the use of oversized cardiac allografts. [Copyright &y& Elsevier]

Background: With improvement in medical outcomes, the current research has shifted toward understanding and enhancing the quality of life after pediatric heart transplantation. Previous research has indicated that infant heart transplant recipients are generally at risk for neurodevelopmental delays; however, no longitudinal studies exploring the patterns of development within this medical population have been performed.Methods: Using the Bayley Scales of Infant Development—II, 39 children (2 to 38 months of age) who underwent heart transplantation in infancy (<1 year) at Loma Linda University Children''s Hospital were assessed consecutively over time.Results: Mean Mental Development Index (MDI) scores for all age groups were within normal limits, except for the age ranges of 18 to 23 and 24 to 35 months, which were mildly delayed. Average Psychomoter Development Index (PDI) scores for all age groups reflected mildly delayed performance, except for the 36- to 38-month age group, which was within normal limits. Repeated measures analyses of variance on a sub-set of participants with at least 4 consecutive assessments revealed within-subject effects on MDI scores (F = 5.7, p < 0.01), but not on PDI scores (F = 1.6, p = 0.22). Significant decreases in MDI scores at 18 and 28 to 36 months were noted.Conclusions: Motor development in this population was consistently mildly delayed. Age-dependent variability in cognitive skills was apparent. The delays appeared due to speech/language acquisition (18 months), and abstract reasoning/goal-directed behaviors (28 to 36 months). Possible etiologies for cognitive delays include test artifacts, auditory functioning and effects of immunosuppressive agents. Understanding risk factors in this patient population will allow for early and effective intervention. [Copyright &y& Elsevier]

: Background:Acute rejection commonly occurs within the first year after heart transplantation, and then decreases in frequency with time. Recently, the long-term utility of endomyocardial biopsy during routine annual catheterization has been questioned. The purpose of this study was to retrospectively review the prevalence of biopsy-proven rejection during routine annual catheterization in our patient population, determine whether biopsies late after transplant are useful, and identify factors that correlate with late unsuspected rejection.: Methods:Biopsy results from the annual catheterization were evaluated from 1986 to August 2000. The prevalence of moderate rejection was evaluated and compared with the patient’s immunosuppressive regimen; the prevalence of late rejection; and how late rejection correlated with recipient age, number of first-year rejections and presence of sub-therapeutic cyclosporine.: Results:A total of 1,108 biopsies were performed in 269 children with a mean follow-up of 5 ± 3 years (median 5 years, range 1 to 11 years). Three-drug immunosuppressive therapy, including steroids, was used in 93 patients. There was a persistent 8% to 10% prevalence of moderate rejection at up to 10 years post-transplantation. Moderate rejection was more likely in patients: (1) on 3-drug immunosuppressive therapy; (2) with a recipient age >1 year; and (3) with a relatively lower cyclosporine level.: Conclusions:These data suggest that continued surveillance of pediatric transplant patients for acute rejection is indicated for long-term follow-up. [Copyright &y& Elsevier]