Cardiac Transplantation in Pediatric Patients: Fifteen-Year Experience of a Single Center

Approval of Mycophenolate Mofetil for Prophylaxis of Organ Rejection in Pediatric Recipients of Heart or Liver Transplants: A Regulatory Perspective

On June 6, 2022, the FDA expanded the indications for mycophenolate mofetil (MMF) to include the prophylaxis of organ rejection in combination with other immunosuppressants in pediatric recipients of allogeneic heart or liver transplants aged 3 months and older. The approved oral dosing regimen for these patients was a starting dose of 600 mg/m2 with titration up to a maximum of 900 mg/m2 twice daily. Data to support efficacy in pediatric patients were derived from established pharmacokinetic (PK) relationships across approved populations, a PK study in pediatric liver transplant recipients, and information from the Scientific Registry of Transplant Recipients database. Information supporting safety was based on comparing mycophenolic acid (MPA) exposure with that in pediatric kidney transplant recipients, the published literature, and post-marketing safety reports. Efficacy in pediatric patients was established based on extrapolation of efficacy from studies in adult liver, adult heart, and pediatric kidney transplant populations, and similarity in MPA exposure between pediatric and adult patients. Review of the data supported an oral dosing regimen for pediatric heart transplant and liver transplant recipients consisting of a starting dose of 600 mg/m2 up to a maximum of 900 mg/m2 b.i.d. A dosage range for MMF is recommended recognizing that the MMF dose may be modified in clinical practice for myriad factors. The dosage recommendations in the labeling for pediatric liver and pediatric heart transplant patients are intended to permit individualized dosing based on clinical assessment of these factors.

Pediatric heart transplantation: Looking forward after five decades of learning

Heart transplantation has become the standard of care for pediatric patients with end-stage heart disease throughout the world. Since the first transplant was performed in 1967, the number of transplants has grown dramatically with 13 449 pediatric heart transplants being reported to The International Society of Heart and Lung Transplant (ISHLT) between January 1992 and June 30, 2018. Outcomes have consistently improved over the last few decades, specifically short-term outcomes. Most recent survival data demonstrate that recipients who survive to 1-year post-transplant have excellent long-term survival with more than 60% of those who were transplanted as infants being alive 25 years later. Nonetheless, the rates of graft loss beyond the first year have remained relatively constant over time; driven primarily by our poor understanding and lack of treatments for chronic allograft vasculopathy (CAV). Acute rejection, CAV, graft failure, and infection continue to be the major causes of death within the first 5 years post-transplant. In addition, renal dysfunction, malignancy, and the need for re-transplantation remain as significant issues that require close follow-up. Looking forward, key challenges include improving donor utilization rates (including donation after cardiac death (DCD) and the use of ex vivo perfusion devices), the development of non-invasive biomarkers for rejection, efforts to mitigate the long-term effects of immunosuppression, and prevention of CAV. It is not possible to cover the entire evolution of pediatric heart transplantation over the last five decades, but in this review, we hope to touch on key observations, lessons learned, and practice changes that have advanced the field, as well as glance ahead to the next decade.

Pulmonary hemodynamics before and after pediatric heart transplantation

BACKGROUND

Pulmonary hypertension (PH) may limit the outcome of pediatric heart transplantation (pHTx). We evaluated pulmonary hemodynamics in children undergoing pHTx.

METHODS

Cross-sectional, single-center, observational study analyzing pulmonary hemodynamics in children undergoing pHTx.

RESULTS

Twenty-three children (female 15) underwent pHTx at median (IQR) age of 3.9 (.9-8.2) years with a time interval between first clinical signs and pHTx of 1.1 (.4-3.2) years. Indications for pHTx included cardiomyopathy (CMP) (n = 17, 74%), congenital heart disease (CHD) (n = 5, 22%), and intracardiac tumor (n = 1, 4%). Before pHTx, pulmonary hemodynamics included elevated pulmonary artery pressure (PAP) 26 (18.5-30) mmHg, pulmonary capillary wedge pressure (PCWP) 19 (14-21) mmHg, left ventricular enddiastolic pressure (LVEDP) 17 (13-22) mmHg. Transpulmonary pressure gradient (TPG) was 6.5 (3.5-10) mmHg and pulmonary vascular resistance (Rp) 2.65 WU*m2 (1.87-3.19). After pHTx, at immediate evaluation 2 weeks after pHTx PAP decreased to 20.5 (17-24) mmHg, PCWP 14.5 (10.5-18) mmHg (p < .05), LVEDP 16 (12.5-18) mmHg, TPG 6.5 (4-12) mmHg, Rp 1.49 (1.08-2.74) WU*m2 resp.at last invasive follow up 4.0 (1.4-6) years after pHTx, to PAP 19.5 (17-21) mmHg (p < .05), PCWP 13 (10.5-14.5) mmHg (p < .05), LVEDP 13 (10.5-14) mmHg, TPG 7 (5-9.5) mmHg, Rp 1.58 (1.38-2.19) WU*m2 (p < .05). In CHD patients PAP increased (p < .05) after pHTx at immediate evaluation and decreased until last follow-up (p < .05), while in CMP patients there was a continuous decline of mean PAP values immediately after HTx (p < .05).

CONCLUSIONS

While PH before pHTx is frequent, after pHTx the normalization of PH starts immediately in CMP patients but is delayed in CHD patients.

Effects of WuZhi preparations on tacrolimus in pediatric and adult patients carrying the CYP3A5*1 allele of heart transplant during the early period after transplantation

AIM

Wuzhi preparations (WZP) are commonly administrated with tacrolimus (TAC) in China to improve the liver function and increase the exposure of TAC. This study aims to investigate the effects of WZP on TAC in pediatric heart transplantation (HTx) patients carrying the CYP3A5*1 allele during the early period after transplantation and also make a comparison with these effects in adult recipients.

METHODS

A total of 81 recipients with CYP3A5*1 allele were included and divided into the pediatric group (n = 29) and adult group (n = 52). The changes in TAC dose-corrected trough blood concentrations (C0 /D), dose requirement as well as intra-patient variability(IPV) of C0 /D after co-therapy with WZP were evaluated.

RESULTS

The TAC C0 /D was significantly increased 1.7 and 1.8 times after co-administration of WZP in the pediatric and adult groups, respectively. We further analyzed the pediatric patients, found that no statistical difference was observed in TAC C0 /D before and after co-therapy with WZP in children <6 years old. The changes of C0 /D increased with the dose of the active ingredient (Schisantherin A) in adult patients, but not in pediatric patients. TAC IPV was reduced by 10.5% in pediatric patients and 4.8% in adult patients when co-administrated with WZP. Furthermore, after taking WZP, the AST and TB were dramatically lowered in pediatric recipients.

CONCLUSION

Our study is the first attempt to demonstrate the effects of WZP on TAC in pediatric HTx recipients. By comparing these effects to those observed in adult recipients, valuable insights can be gained regarding the efficacy and potential benefits of WZP in the pediatric population.

CYP3A4/5 genotypes and age codetermine tacrolimus concentration and dosage in pediatric heart transplant recipients

Tacrolimus (TAC) is the cornerstone of immunosuppressive therapy for pediatric heart transplantation (HTx) recipients. However, little information is known on the interaction of developmental and genetic variants on TAC disposition in this population, which makes TAC dose optimization more difficult. The aim of study was to investigate the relationship between genotypes and age on TAC concentrations and dosage during the early post-operation period in pediatric HTx recipients. Sixty-six pediatric HTx recipients were enrolled and divided into three groups according to the age (<6, ≥6-≤12, 12-18 years old). CYP3A4/5, POR and ABCB1 polymorphisms were genotyped. The associations between genotypes and age on TAC dose-adjusted trough concentrations (C₀/D), dose requirement as well as acute kidney injury (AKI) were evaluated. CYP3A5*3 and CYP3A4*1G were significantly correlated with TAC C₀/D and dose requirement in the pediatric recipients ≥ 6 years. The C₀/D in children aged ≥ 6-≤12 years and 12-18 years is 2.8 and 4.2 fold of these < 6 years old, respectively. TAC dose requirements in children aged < 6 years were 2.4 times and 3.5 times of these aged ≥ 6-≤12 years and 12-18 years, respectively. Among the same CYP3A5*3 or CYP3A4*1G genotypes, age was positively increased with TAC C₀/D and negatively correlated with targeted dose. No genetic variants were found to be associated with AKI during the early post-operation period. CYP3A4/5 genotypes and age should be taken into consideration to TAC dosage in pediatric HTx recipients.

Pathways to Clinical Cardiac Xenotransplantation

Heart transplantation is the only long-lasting lifesaving option for patients with terminal cardiac failure. The number of available human organs is however far below the actual need, resulting in substantial mortality of patients while waiting for a human heart. Mechanical assist devices are used to support cardiac function but are associated with a high risk of severe complications and poor quality of life for the patients. Consistent success in orthotopic transplantation of genetically modified pig hearts into baboons indicates that cardiac xenotransplantation may become a clinically applicable option for heart failure patients who cannot get a human heart transplant. In this overview, we project potential paths to clinical cardiac xenotransplantation, including the choice of genetically modified source pigs; associated requirements of microbiological, including virological, safety; optimized matching of source pig and recipient; and specific treatments of the donor heart after explantation and of the recipients. Moreover, selection of patients and the regulatory framework will be discussed.

Primary Transplantation for Congenital Heart Disease in the Neonatal Period: Long-term Outcomes

BACKGROUND

Primary transplantation was developed in the 1980s as an alternative therapy to palliative reconstruction of uncorrectable congenital heart disease. Although transplantation achieved more favorable results, its utilization has been limited by the availability of donor organs. This review examines the long-term outcomes of heart transplantation in neonates at our institution.

METHODS

The institutional pediatric heart transplant database was queried for all neonatal heart transplants performed between 1985 and 2017. Follow-up was obtained from medical records and an annually administered questionnaire. Overall survival and time to development of complications were estimated using the Kaplan Meier method. Univariate and multivariate analyses were performed to identify independent predictors of survival.

RESULTS

Heart transplantation was performed in 104 neonates. Median age was 17 days. Hypoplastic left heart syndrome (classic or variant) was the primary diagnosis in 77.8% of patients. Survival at 10 years and 25 years was 73.9% and 55.8%, respectively. At 20 years, freedom from allograft vasculopathy and lymphoproliferative disease was 72.0% and 81.9%, respectively. Freedom from re-transplantation was 81.4% at 20 years. Eight patients (7.6%) developed end-stage renal disease. By multivariate analysis, lower glomerular filtration rate and allograft vasculopathy were the only significant predictors of death.

CONCLUSIONS

Neonatal heart transplantation remains a durable therapy with very acceptable long-term survival. Children transplanted in the newborn period have the potential to reach adulthood with minimal need for reintervention.

Moderate-severe primary graft dysfunction after pediatric heart transplantation

BACKGROUND

PGD is a complication after heart transplantation (OHT) and a significant cause of mortality, particularly in infant recipients. Lack of standardized definition of PGD in the pediatric population makes the prevalence and magnitude of impact unclear.

METHODS

ISHLT PGD consensus guidelines, which include inotrope scores and need for MCS, were applied retrospectively to 208 pediatric OHT recipients from a single institution from 1/2005-5/2016. PGD was defined as: moderate PGD-inotrope score >10 on postoperative day 1 (24-48 hours), and severe PGD-MCS within 24 hours (in the absence of detectable rejection).

RESULTS

PGD occurred in 34 patients (16.3%); 14 of which had severe PGD (6.7%). Multivariate risk factors for PGD included CPB time (OR 10.3/10 min, 95% 10.05, 10.2, P = 0.03), Fontan palliation (OR 1.9, 95% 1.2, 3.97), and PCM (OR 5.65, 95% 1.52, 22.4); but not age, weight, ischemic time, or donor characteristics. Upon sub-analysis excluding patients with PCM, increased CPB was a significant multivariate risk factor (OR 10.09, 95% 9.89, 10.12, P = 0.003). Patients with PGD had decreased discharge survival compared to those without PGD (85% vs 96%, P < 0.01). Severe PGD was associated with the poorest 1-year survival (57% vs 91% without PGD, P = 0.04).

CONCLUSION

Patients with prolonged CPB are potentially at risk for developing PGD. Neither infant recipients nor donor characteristics were associated with an increased risk of PGD in the current era.

Psoriasis: Which therapy for which patient: Psoriasis comorbidities and preferred systemic agents

Psoriasis is a systemic inflammatory disease associated with increased risk of comorbidities, such as psoriatic arthritis, Crohn's disease, malignancy, obesity, and cardiovascular diseases. These factors have a significant impact on the decision to use one therapy over another. The past decade has seen a paradigm shift in our understanding of the pathogenesis of psoriasis that has led to identification of new therapeutic targets. Several new drugs have gained approval by the US Food and Drug Administration, expanding the psoriasis armamentarium, but still a large number of patients continue to be untreated or undertreated. Treatment regimens for psoriasis patients should be tailored to meet the specific needs based on disease severity, the impact on quality of life, the response to previous therapies, and the presence of comorbidities. The first article in this continuing medical education series focuses on specific comorbidities and provides insights to choose appropriate systemic treatment in patients with moderate to severe psoriasis.

Pediatric Heart Transplantation Long-Term Survival in Different Age and Diagnostic Groups: Analysis of a National Database

BACKGROUND

The purpose of this study was to evaluate differences in long-term survival without the influence of early mortality, and to identify factors associated with one-year conditional ten-year survival after heart transplantation (HTx) across different age and diagnostic groups.

METHODS

Organ Procurement and Transplant Network data from January 1990 to December 2005 were used. Cohort was divided according to age (infants [<1 year], children [>1-10 years], and adolescents [11-18 years]) and diagnosis (cardiomyopathy and congenital heart disease [CHD]). Factors associated with one-year conditional ten-year survival were identified using multivariable logistic regression and using a case-control design.

RESULTS

One-year conditional ten-year survivors included 1,790 patients compared to 1,114 patients who died after the first posttransplant year and within ten years of transplant with a median follow-up of 4.8 years. Predictors of one-year conditional ten-year survival for infants were recipient's Caucasian race (odds ratio [OR]: 1.9, 95% confidence interval [CI]: 1.3-2.7) and donor-recipient weight ratio (OR: 0.8, 95% CI: 0.6-1); for children: Caucasian race (OR: 1.6, 95% CI: 1.2-2.1), retransplantation (OR: 0.4, 95% CI: 0.2-0.6), and transplantation after the year 2000 (OR: 1.5, 95% CI: 1.1-2.1); for adolescents only Caucasian race (OR: 2.5, 95% CI: 1.9-2.3). In both CHD and cardiomyopathy, adolescents had worse survival compared to infants and children. There was an era effect with improved survival after 2000. Male gender was a predictor of survival in cardiomyopathy group.

CONCLUSION

Predictors of one-year conditional ten-year survival varied among groups. These data and analyses provide important information that may be useful to clinicians, particularly when counseling patients and families regarding expectations of survival after pediatric HTx.

Hearts transplanted after circulatory death in children: Analysis of the International Society for Heart and Lung Transplantation registry

We aimed to describe worldwide DCD HT experience in children using the International Society for Heart and Lung Transplantation Registry. The Registry was queried for primary HT performed in children (2005-2014). Kaplan-Meier analysis was used to assess survival for recipients grouped by DCD or DBD hearts. Recipient characteristics were compared between DCD and DBD and between survivors and non-survivors of DCD HT. Among 3877 pediatric HT performed, 21 (0.5%) were DCD. DCD 1-year survival was 61% vs 91% DBD, P < .01. DCD recipients were more often supported by ECMO pre-HT (24% vs 6%, P < .001) and more often receiving inhaled nitric oxide (10% vs 0.6%, P < .001) compared to DBD. Older DCD recipients had significantly lower 1-year survival of 57% vs 93% for DBD, P < .01. Survival for infant DCD recipients was not statistically different to DBD recipients (survival 62% at 1 year and 62% at 5 years for DCD vs 85% at 1 year and 77% at 5 years for DBD, P = .15). Recipients of DCD HT who died were more often supported by ECMO pre-HT (56% non-survivors vs 0% survivors, P = .004) and receiving mechanical ventilation (44% vs 0%, P = .012). DCD HT is uncommon in children. DCD-independent factors in recipients may have contributed to worse survival as DCD recipients who died were more often supported by ECMO and mechanical ventilation. More research is needed to identify donor factors and recipient factors that contribute to mortality after DCD HT.

End-stage renal disease after pediatric heart transplantation: A 25-year national cohort study

BACKGROUND

End-stage renal disease (ESRD), defined as the need for chronic dialysis and/or kidney transplantation (KTx), is a known complication after heart transplant (HTx). However, factors associated with ESRD are not well elucidated. The objectives of this study were to determine the prevalence, risk factors, and outcomes associated with ESRD after pediatric HTx.

METHODS

Scientific Registry of Transplant Recipients data were linked, using direct identifiers, to the United States Renal Data System to identify patients (aged ≤ 18 years) who underwent primary HTx between 1989 and 2013. Risk factors for ESRD and death were analyzed using Cox regression analysis.

RESULTS

Combining the above 2 databases identified ~25% additional HTx patients who developed ESRD that were not captured by either database alone. During a median follow-up of 11.8 years, ESRD developed in 276 of 6,901 patients (4%). The actuarial risk of developing ESRD after HTx was 3% at 10 years and 16% at 20 years. Age at HTx > 1 year, African-American race, year of HTx before 2000, hypertension, diabetes mellitus, re-HTx, acute dialysis, graft failure, and hospitalized infection were significant risk factors for ESRD development. Those who remained on chronic dialysis had higher risk of death than those who received KTx (hazard ratio, 31.4; 95% confidence interval, 20.8-48.4; p < 0.0001).

CONCLUSIONS

ESRD after pediatric HTx is more prevalent in HTx survivors than documented by a transplant database alone. A number of factors develop at or after HTx that increase the risk for developing ESRD. Use of KTx in post-HTx ESRD is associated with improved survival.

Rehospitalization after pediatric heart transplantation: Incidence, indications, and outcomes

We report the patterns of rehospitalization after pediatric heart transplant (Htx) at a single center. Retrospective review of 107 consecutive pediatric Htx recipients between January 22, 2007, and August 28, 2014, who survived their initial transplant hospitalization. The frequency, duration, and indications for all hospitalizations between transplant hospitalization discharge and September 30, 2015, were analyzed. A total of 444 hospitalization episodes occurred in 90 of 107 (84%) patients. The median time to first rehospitalization was 59.5 (range 1-1526) days, and the median length of stay was 2.5 (range 0-81) days. There were an average of two hospitalizations per patient in the first year following transplant hospitalization, declining to about 0.8 per patient per year starting at 3 years post-transplant. Admissions for viral infections were most common, occurring in 93 of 386 (24%), followed by rule out sepsis in 61 of 386 (16%). Admissions for suspected or confirmed rejection were less frequent, accounting for 41 of 386 (11%) and 31 of 386 (8%) of all admissions, respectively. Survival to discharge after rehospitalization was 97%. Hospitalization is common after pediatric Htx, particularly in the first post-transplant year, with the most frequent indications for hospitalization being viral illness and rule out sepsis. After the first post-transplant year, the risk for readmission falls significantly but remains constant for several years.

Late outcome after paediatric heart transplantation in Finland

OBJECTIVES

We studied the long-term survival and rejection episodes of paediatric heart transplant recipients.

METHODS

We included all paediatric patients (≤18 years) who underwent heart transplantation during 1991-2014 in Finland. Data were obtained retrospectively from a paediatric cardiac surgery database. Patient status was received from the Finnish population registry. All patients underwent yearly routine postoperative endomyocardial biopsies and coronary angiographies.

RESULTS

Between 1991 and 2014, 68 heart transplantations were performed. The early mortality (<30 days after surgery) rate was 10% and follow-up coverage was 100%. The 10- and 15-year survival rates for all patients were 68% (95% confidence internal, CI, 56-80%) and 65% (95% CI 53-78%), respectively, including early mortality. The 1-year survival rate was 100% when excluding early operative mortality. Indications for heart transplantation were cardiomyopathy in 57% and cardiac malformations in 43% of patients, with similar long-term survival between the groups. During 23 years of follow-up, 43 patients (70%) had at least one rejection episode and 17 patients (29%) at least a grade 1 coronary artery vasculopathy finding. Patients with early rejection episodes (<3 months) had a higher incidence of late rejection episodes (P = 0.025). Older age at operation was a significant risk factor for the development of coronary artery vasculopathy (hazard ratio 1.1, 95% CI 1.0-1.3, P = 0.012).

CONCLUSIONS

First-year survival was excellent. Asymptomatic rejection episodes were common among patients. Early rejection episodes are a risk factor for late rejection episodes and show a trend towards an increased risk of late death. Coronary artery vasculopathy remains a major challenge for late graft survival.

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/m(2) ) 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.

Viral endomyocardial infection in the 1st year post transplant is associated with persistent inflammation in children who have undergone cardiac transplant

BACKGROUND

Viral genome in cardiac allograft has been associated with early graft loss in children who have undergone cardiac transplant from unknown mechanisms.

METHODS

This study is a retrospective review of children who have undergone cardiac transplant at a single institution from 1/2004 to 5/2008. Patients underwent cardiac catheterisations with endomyocardial biopsies to evaluate for rejection--graded on Texas Heart Institute scale--and the presence of virus by polymerase chain reaction. Patients with virus identified during the first year post transplant were compared at 1 year post transplant with virus-free patients.

RESULTS

The cohort comprised 59 patients, and the median age at transplant was 5.1 years. Viral genomes were isolated from 18 (31%) patients. The PCR + group had increased inflammation on endomyocardial biopsies, with a median score of 4 (ISHLT IR) versus 1 (ISHLT 1R) in the PCR--group (p = 0.014). The PCR + group had a similar cardiac index (median 3.7 ml/min/m(2)), pulmonary capillary wedge pressure (median 10 mmHg), and pulmonary vascular resistance index (median 1.7 U m(2)) comparatively. PCR + patients were more likely to have experienced an episode of rejection (p = 0.004).

CONCLUSIONS

Children who developed viral endomyocardial infections after a cardiac transplant have increased allograft inflammation compared with virus-free patients. However, the haemodynamic profile is similar between the groups. The ongoing subclinical inflammation may contribute to the early graft loss associated with these patients.

Heart Transplantation for Congenital Heart Disease

Congenital heart disease affects 0.8% of all live-born infants. Some of the malformed hearts can at best be palliated by conventional surgical or catheter interventions from the start. Others fail slowly from chronic overloading. Patients with congenital heart disease have been among the first transplant recipients since 1967. Primary therapy with infant heart transplant is a convincing concept from an immunological perspective but large-scale implementation is limited by donor organ shortages. Another growing area is rescue therapy for older patients with end-stage heart failure after palliative procedures, particularly those with single-ventricle hearts, systemic right ventricles, and associated arrhythmias.

HLA antibodies in pediatric heart transplantation

We have analyzed the impact of anti-HLA antibodies present in the patients' circulation prior and/or following heart transplantation in a population of 108 pediatric recipients. Anti-HLA class I and class II antibodies were monitored by traditional CDC using donor and panel T and B lymphocytes and by SPA for detection of DSA. There was a highly significant correlation between the development of AMR and presence of CDC- or SPA-detected DSA. However, the fraction of the transplant population which remained AMR-free was much higher among patients with SPA-detected compared to CDC-detected DSA. Furthermore, long-term graft survival was negatively affected only by cytotoxic, complement-fixing anti-HLA class I antibodies developing following transplantation. Anti-HLA class I or class II antibodies detected by SPA had no effect on long-term survival rates.

Invasive Candida infections in solid organ transplant recipient children

Solid organ transplantation (SOT) is now an accepted therapy for many end-stage organ disorders and fungal infections are the principal cause of infection-related mortality in SOT recipients. Among invasive fungal infections, Candida species are the most common pathogens identified, associated with high mortality rates. The epidemiology and clinical manifestations of Candida infections vary with the type of organ transplantation. This article reviews invasive Candida infections in pediatric SOT recipients.

Late outcomes of pediatric heart transplantation are independent of pre-transplant diagnosis and prior cardiac surgical intervention

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.

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

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 m(2)). 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 m(2)) 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 m(2). 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.

In-hospital cerebrovascular complications following orthotopic liver transplantation: a retrospective study

Background

Cerebrovascular complications are severe events following orthotopic liver transplantation (OLT). This study aimed to observe the clinical and neuroimaging features and possible risk factors of in-hospital cerebrovascular complications in the patients who underwent OLT.

Patients and methods

We retrospectively reviewed 337 consecutive patients who underwent 358 OLTs. Cerebrovascular complications were determined by clinical and neuroimaging manifestations, and the possible risk factors were analyzed in the patients with intracranial hemorrhage.

Results

Ten of 337 (3.0%) patients developed in-hospital cerebrovascular complications (8 cases experienced intracranial hemorrhage and 2 cases had cerebral infarction), and 6 of them died. The clinical presentations were similar to common stroke, but with rapid deterioration at early stage. The hematomas on brain CT scan were massive, irregular, multifocal and diffuse, and most of them were located at brain lobes and might enlarge or rebleed. Infarcts presented lacunar and multifocal lesions in basal gangliar but with possible hemorrhagic transformation. The patients with intracranial hemorrhage had older age and a more frequency of systemic infection than non-intracranial hemorrhage patients. (P = 0.011 and 0.029, respectively).

Conclusion

Posttransplant cerebrovascular complications have severe impact on outcome of the patients who received OLT. Older age and systemic infection may be the possible risk factors of in-hospital intracranial hemorrhage following OLT.

Calcineurin inhibitor sparing in paediatric solid organ transplantation : managing the efficacy/toxicity conundrum

Despite their efficacy, the calcineurin inhibitors (CNIs) ciclosporin and tacrolimus carry a risk of debilitating adverse effects, especially nephrotoxicity, that affect the long-term outcome and survival of children who are given organ transplants. Simple reduction in dosage of CNI has little or no long-term benefit on their adverse effects, and complete withdrawal without threatening graft outcome may only be possible after liver transplantation. Until the last decade, the only option was to increase corticosteroid and/or azathioprine doses, which imposed additional long-term hazards. Considered here are the emerging generation of new agents offering an opportunity for improving long-term graft survival, minimizing CNI-related adverse events and ensuring patient well-being.A holistic, multifaceted strategy may need to be considered - initial selection and optimized use and monitoring of immunosuppressant regimens, early recognition of indicators of patient and graft dysfunction, and, where applicable, early introduction of CNI-sparing regimens facilitating CNI withdrawal. The evidence reviewed here supports these approaches but remains far from definitive in paediatric solid organ transplantation. Because de novo immunosuppression uses CNI in more than 93% of patients, reduction of CNI-related adverse effects has focused on CNI sparing or withdrawal.A recurring theme where sirolimus and mycophenolate mofetil have been used for this purpose is the importance of their early introduction to limit CNI damage and provide long-term benefit: for example, long-term renal function critically reflects that at 1 year post-transplant. While mycophenolic acid shows advantages over sirolimus in preserving renal function because the latter is associated with proteinuria, sirolimus appears the more potent immunosuppressant but also impairs early wound healing. The use of CNI-free immunosuppressant regimens with depleting or non-depleting antibodies plus sirolimus and mycophenolic acid needs much wider investigation to achieve acceptable rejection rates and conserve renal function. The adverse effects of the alternative immunosuppressants, particularly the dyslipidaemia associated with sirolimus, needs to be minimized to avoid replacing one set of adverse effects (from CNIs) with another. While we can only conjecture that judicious combinations with the second generation of novel immunosuppressants currently in development will provide these solutions, a rationale of low-dose therapy with multiple immunosuppressants acting by complementary mechanisms seems to hold the promise for efficacy with minimal toxicity until the vision of tolerance achieves reality.

Waiting before birth: outcomes after fetal listing for heart transplantation

Following fetal diagnosis of a profound heart defect, transplantation (HTx) is an alternative to pregnancy termination or neonatal surgical palliation. Retrospective review of the cardiac and transplant databases of fetal listings for HTx between 1990 and July 2006 was undertaken to describe outcomes after listing. We identified 26 fetal listings (of 269 total listings). Diagnoses included congenital heart disease (n = 24) and cardiomyopathy (n = 2). Seven patients were delisted after birth: in five cases parents opted for surgical palliation, two clinically improved. One patient died wait-listed (stillborn). Time wait-listed as a fetus ranged from 1-41 days (median 19 days). Eighteen patients underwent HTx (median weight 2.8 kg, range 2.1-10.9 kg); median days wait-listed after birth was 22 (4 h-123 days). Two fetuses were surgically delivered at 36 weeks gestation when a donor organ became available; 11 were transplanted as neonates (<30 days). The median age at HTx was 1 month (4 h-2.6 months). Fetal listing for HTx increases the potential window of opportunity for a donor organ to become available; patients had low wait-list mortality and a fair intermediate-term outcome. Well-defined criteria for eligibility for fetal listing and priority allocation to infants over fetuses seem rational approaches for centers that offer fetal listing.

Idiopathic dilated cardiomyopathy in children; Natural history and predictors of prognosis

Dilated cardiomyopathy is the most common type of heart muscle disease in children with idiopathic etiology in the majority of cases. Idiopathic dilated cardiomyopathy (IDCM) is a severe illness which carries a high mortality rate in the pediatric population. In order to characterize IDCM evolution and identify prognostic predictors in our pediatric cardiology center in the western province of Saudi Arabia, 55 patients with IDCM were evaluated clinically and by echocardiography. They were followed for a minimum of one year and a maximum of four and a half years. Patients less than two years of age represented 69% of the cohort. Gender distribution revealed 65.5% female and 35.5% male. Outcomes were divided into four groups: 25 patients (45.5%) improved (Group I), 17 patients (31%) had a stationary course (Group II), 13 patients (23.6%) deteriorated (Group III), and eventually 11 patients (from Group III) died. Survival rate was 80% with a mean follow-up period of 36.2 ± 22.1 months. The older the age at presentation, the worse the prognosis, with P value= 0.029. In this study, we found a significant correlation of prognosis with end diastolic volume (EDV) (P=0.05) as well as stroke volume (SV) (P=0.04) on presentation. However, fractional shortening of ejection fraction on presentation could not be correlated statistically to the prognosis. Also results suggested that higher z-score of intraventricular septum & Left ventricular posterior wall dimensions in diastole significantly correlated to favorable outcomes and higher z-score of Left ventricular end diastolic dimension (LVEDD) was significantly related to unfavorable outcome. We concluded that further multi-center studies are necessary to verify predictors of outcome in IDCM patients. Identification of markers affecting early myocardial function is essential to achieving improvements in treatments and consequently outcomes in this pediatric population.

Over two decades of pediatric heart transplantation: How has survival changed?

OBJECTIVE

In 1984, the first successful infant heart transplant was performed at Texas Children's Hospital. This study analyzes the 21-year experience with pediatric heart transplantation at Texas Children's Hospital to assess whether and how survival has changed over time.

METHODS

Between November 1, 1984, and October 3, 2005, 164 consecutive orthotopic heart transplants were performed on 154 patients. Characteristics: mean age 7.1 +/- 6.0 years, mean body surface area 0.8 +/- 0.5 m(2). Diagnosis at transplant: cardiomyopathy 53.0% (n = 87), congenital heart defect 39.0% (n = 64), retransplant 7.9% (n = 13). Multivariate risk factor analysis of 32 variables was completed by Cox proportional hazards regression models.

RESULTS

Mean follow-up was 5.9 +/- 4.8 years. Overall Kaplan-Meier survival was 82% at 1 year, 65% at 5 years, and 54% at 10 years. After 1995, Kaplan-Meier survival (91% at 1 year and 71% at 5 years) was significantly improved over pre-1995 survival (71% at 1 year, 57% at 5 years, and 48% at 10 years; P =.026). Hospital survival improved in the post-1995 era (96%) compared with the pre-1995 era (77%; P < .001). Life-table analysis by yearly increments demonstrates only an improved survival (pre-1995, 71% -->post-1995, 91%) in the first posttransplant year (P = .001); every subsequent year the mortality rates are the same (P = .92). Risk factors for overall mortality are prolonged postoperative intubation (>5 days) and longer cardiopulmonary bypass time.

CONCLUSIONS

Primarily attributable to an increase in early survival, overall pediatric heart transplant survival is improved. However, after the first posttransplant year, the rate of mortality has not changed in 21 years. This highlights the need for new therapies to treat children both with or in need of a heart transplant.

Chronic Respiratory Complications in Pediatric Heart Transplant Recipients

BACKGROUND

The frequency and spectrum of chronic respiratory complications in pediatric heart transplant recipients have not been extensively studied. The aim of this study was to describe the chronic respiratory complications in 126 consecutive pediatric heart transplant recipients.

METHODS

Retrospective review of medical records.

RESULTS

Between 1987 and 2005, 126 (64 males and 62 females) heart transplantations were performed at Freeman Hospital, Newcastle upon Tyne, United Kingdom. The median age at transplantation was 7.4 years (range, 0.1-17) and the median length of follow-up was 6.8 years (range, 0-18.2). Twenty-four patients have died, and 36 have been transferred to adult follow-up, leaving 66 under pediatric follow-up. Chronic respiratory complications have been documented in 33 children (50%). Bronchiectasis has been identified in 10 children, and 12 further children have had recurrent lower respiratory tract infections (without bronchiectasis) requiring long-term antibiotic prophylaxis. Of those with infectious complications, 81% underwent transplantation before 4 years and had deficiency of pneumococcal-specific antibody response. Obstructive sleep apnea has occurred in 5 children, sub-glottic stenosis has occurred in 3, and significant compression of the left main stem bronchus related to a disproportionately large donor heart has occurred in 2. One child had marked mosaic attenuation on chest computed tomography scan indicative of small airways disease.

CONCLUSION

Chronic respiratory complications are common in pediatric heart transplant recipients. The respiratory prognosis for this complex group of patients is usually good, but long-term follow-up by both a respiratory pediatrician and an immunologist is frequently required.

Update in adult congenital cardiac surgery

The number of grown-up patients with congenital heart disease (GUCH) is constantly increasing and will equal the number of children requiring surgery for congenital heart disease (CHD). Specialized centers dealing with the medical and paramedical problems of these patients are required. GUCH patients can be divided into the following groups: (1) patients with minor cardiac malformations presenting at adult age for first treatment; (2) patients presenting for correction as adults because they are either naturally balanced or were surgically palliated; (3) patients presenting for expected reoperations after correction in childhood; (4) patients requiring repair of residual defects after correction; (5) patients developing heart failure after correction or palliation of CHD requiring thoracic transplantation; and (6) patients developing acquired heart disease in addition to CHD. Special aspects of malformations frequently occurring in GUCH patients are discussed in detail. Acquired heart disease in this patient population is expected to increase in the coming decades as survivors of CHD grow old.

Pulmonary Complications in Heart Transplant Recipients

BACKGROUND

Heart transplantation is an important therapeutic option for patients with end-stage disease, but is associated with major pulmonary complications.

PATIENTS AND METHODS

We retrospectively reviewed the posttransplant follow-up of 34 orthotopic heart transplant recipients.

RESULTS

Two of the 34 patients died of cardiac failure in the early postoperative period. Among the surviving patients, 10 (31.3%) developed pulmonary complications, all within the first 6 months: hospital-acquired bacterial pneumonia in five, fungal pneumonia in three, posttransplant lymphoproliferative disease in one, and community-acquired pneumonia in one patient. None of the patients developed transplantation-related malignancy. The overall mortality was 35.3%. Pneumonia-related mortality rate of 14.7% was due to early-onset nosocomial pneumonias, which were caused by bacterial and opportunistic microorganisms. Extrapulmonary causes of mortality were cardiac failure, meningitis, septicemia, and acute rejection. Cytomegalovirus antigenemia in the first month was associated with a poor prognosis. The frequency of pulmonary complications was higher among older patients and those who developed moderate rejection in the first month (P=.014 and P=.036, respectively).

CONCLUSION

Pulmonary infections after heart transplantation occurred more frequently during the first 6 months posttransplantation, accounting for a significant portion of the posttransplantation mortality.

Orthotopic heart transplantation for congenital heart defects: anomalies of the systemic venous return

Anomalies of the systemic venous return are frequently associated with other congenital heart defects. Some anomalies do not complicate really orthotopic heart transplantation (such as azygos continuation of the inferior vena cava). Other anomalies raise more difficulties; the most frequent one is persistent left superior vena cava draining into either the coronary sinus or the left atrium. Sometimes, the left superior vena cava can be ligated without untoward effect. In most cases, the left superior vena cava must be anastomosed to the right atrial compartment, preferably using extracardiac procedures. Most problems can be solved by harvesting extra lengths of donor superior vena cava and innominate vein. In rare patients, associated anomalies of the pulmonary venous return may require additional partitioning of the atria. The early risk of heart transplantation is probably not increased by the presence of such anomalies.

Review of Major Clinical Trials with Mycophenolate Mofetil in Cardiac Transplantation

Over the past 10 years, the addition of mycophenolate mofetil (MMF) to combination immunosuppressive regimens in cardiac transplant patients has resulted in significant outcomes benefits. Randomized trials and other studies have demonstrated that the use of MMF is associated with a decreased risk of rejection and improved survival. This article will provide an overview of these trials, as well as those evaluating MMF in renal-sparing regimens and in pediatric cardiac transplant recipients. In addition, emerging evidence demonstrating that MMF may provide long-term benefits in reducing cardiac allograft vasculopathy and those evaluating the role of MMF therapeutic drug monitoring in cardiac transplant recipients will be discussed.