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

Neonatal heart transplantation in the United States: Trends and outcomes

BACKGROUND

Heart transplantation in the neonatal period is associated with excellent survival. However, outcomes data are scant and have been obtained primarily from two single-center reports within the United States. We sought to analyze the outcomes of all neonatal heart transplants performed in the United States using the United Network for Organ Sharing (UNOS) dataset.

METHODS

The UNOS dataset was queried for patients who underwent infant heart transplantation from 1987 to 2021. Patients were divided into two groups based on age - neonates (<=31 days), and older infants (32 days-365 days). Demographic and clinical characteristics were analyzed and compared, along with follow up survival data.

RESULTS

Overall, 474 newborns have undergone heart transplantation in the United States since 1987. Freedom from death or re-transplantation for neonates was 63.5%, 58.8% and 51.6% at 5, 10, and 20 years, respectively. Patients in the newborn group had lower unadjusted survival compared to older infants (p < .001), but conditional 1-year survival was higher in neonates (p = .03). On multivariable analysis, there was no significant difference in survival between the two age groups (p = .43). Black race, congenital heart disease diagnosis, earlier surgical era, and preoperative mechanical circulatory support use were associated with lower survival among infant transplants (p < .05).

CONCLUSIONS

Neonatal heart transplantation is associated with favorable long-term clinical outcomes. Neonates do not have a significant survival advantage over older infants. Widespread applicability is limited by the small number of available donors. Efforts to expand the donor pool to include non-standard donor populations ought to be considered.

Partial heart transplantation: Growing heart valve implants for children

Heart valves serve a vital hemodynamic function to ensure unidirectional blood flow. Additionally, native heart valves serve biological functions such as growth and self-repair. Heart valve implants mimic the hemodynamic function of native heart valves, but are unable to fulfill their biological functions. We developed partial heart transplantation to deliver heart valve implants that fulfill all functions of native heart valves. This is particularly advantageous for children, who require growing heart valve implants. This invited review outlines the past, present and future of partial heart transplantation.

Subsequent kidney transplant after pediatric heart transplant: Prevalence and risk factors

Pediatric heart failure and transplantation carry associated risks for kidney failure and potential need for kidney transplant following pediatric heart transplantation (KT/pHT). This retrospective, United Network of Organ Sharing study of 10,030 pediatric heart transplants (pHTs) from 1987 to 2020 aimed to determine the incidence of waitlisting for and completion of KT/pHT, risk factors for KT/pHT, and risk factors for nonreceipt of a KT/pHT. Among pHT recipients, 3.4% were waitlisted for KT/pHT (median time of 14 years after pHT). Among those waitlisted, 70% received a KT/pHT, and 18% died on the waitlist at a median time of 0.8 years from KT/pHT waitlisting (median age of 20 years). Moderate-high sensitization at KT/pHT waitlisting (calculated panel reactive antibody, ≥ 20%) was associated with a lower likelihood of KT/pHT (adjusted hazard ratio, 0.67; 95% confidence interval, 0.47-0.95). Waitlisting for heart transplantation simultaneously with kidney transplant (adjusted hazard ratio, 3.73; 95% confidence interval, 2.01-6.92) was associated with increased risk of death on the KT/pHT waitlist. While the prevalence of KT/pHT is low, there is substantial mortality among those waitlisted for KT/pHT. These findings suggest a need to consider novel risk factors for nonreceipt of KT/pHT and death on the waitlist in prioritizing criteria/guidelines for simultaneous heart-kidney transplantation.

Pediatric Cardiac Xenotransplantation: Recommendations for the Ethical Design of Clinical Trials

For children with complex congenital heart problems, cardiac allotransplantation is sometimes the best therapeutic option. However, availability of hearts for pediatric patients is limited, resulting in a long and growing waitlist, and a high mortality rate while waiting. Cardiac xenotransplantation has been proposed as one therapeutic alternative for neonates and infants, either in lieu of allotransplantation or as a bridge until an allograft becomes available. Scientific and clinical developments in xenotransplantation appear likely to permit cardiac xenotransplantation clinical trials in adults in the coming years. The ethical issues around xenotransplantation of the heart and other organs and tissues have recently been examined, but to date, only limited literature is available on the ethical issues that are attendant with pediatric heart xenotransplantation. Here, we summarize the ethical issues, focusing on (1) whether cardiac xenotransplantation should proceed in adults or children first, (2) pediatric recipient selection for initial xenotransplantation trials, (3) special problems regarding informed consent in this context, and (4) related psychosocial and public perception considerations. We conclude with specific recommendations regarding ethically informed design of pediatric heart xenotransplantation trials.

Paediatric heart transplantation: life-saving but not yet a cure

In the 1980s, heart transplantation was the first successful treatment for infants born with hypoplastic left heart syndrome. Infants who have required heart transplantation benefit from immunologic "advantages," including long-term survival free from cardiac allograft vasculopathy. Currently ∼ 90% of children undergoing a heart transplant are reaching their first-year anniversary and the clinical practices of paediatric heart transplantation have dramatically improved. These successes are largely attributed to research sponsored by the Pediatric Heart Transplant Study Group, the International Society of Heart and Lung Transplantation and, more recently, the Non-profits Enduring Hearts and Additional Ventures. Despite these successes, the field is challenged to increase progress to achieve long-term survival into adulthood. The wait-list mortality, especially among infants, is unacceptably high often leading to palliative measures that can increase post-transplant mortality. Cardiac allograft vasculopathy remains a major cause for progressive graft loss of function and sudden death. The relative tolerance seen in immature recipients has not been translated to modifying older recipients' post-transplant outcomes. The modifiable cause(s) for the increased risks of transplantation in children of different ethnicities and races require definition. Addressing these challenges faces the reality that for-profit research favours funding adult recipients, with ∼ 10-fold greater numbers, and their more modest longevity goals. Advocacy for funding "incentives" such as the Orphan Drug rules in the United States and upholding principles of equity and inclusion are critical to addressing the challenges of paediatric heart transplant recipients worldwide.

Partial Heart Transplantation - How to Change the System

Partial heart transplantation is the first clinically successful approach to deliver growing heart valve implants. To date, 13 clinical partial heart transplants have been performed. However, turning partial heart transplantation into a routine procedure that is available to all children who would benefit from growing heart valve implants poses formidable logistical challenges. Firstly, a supply for partial heart transplant donor grafts needs to be developed. This challenge is complicated by the scarcity of donor organs. Importantly, the donor pools for orthotopic heart transplants, partial heart transplants and cadaver homografts overlap. Secondly, partial heart transplants need to be allocated. Factors relevant for equitable allocation include the indication, anatomical fit, recipient clinical status and time on the wait list. Finally, partial heart transplantation will require regulation and oversight, which only recently has been undertaken by the Food and Drug Administration, which regulates human cellular and tissue-based products. Overcoming these challenges will require a change in the system. Once this is achieved, partial heart transplantation could open new horizons for children who require growing tissue implants.

The care of the patients with hipoplastic left heart syndrome in places of social and economic vulneability. An ethical analysis

The birth of a child means hope and joy, particularly for the parents and the healthcare team. When this child is born with a severe malformation and a poor prognosis, as in the case of hypoplastic left heart syndrome, the scenario is one of great uncertainty and emotional suffering. The role of the health team becomes fundamental for the identification of conflicts of values and for the search for shared decisions that promote the best benefit to the child. When the diagnosis is made during fetal life, it is necessary to develop counseling strategies appropriate to the context of each family. In places with limited care resources, precarious prenatal care and short temporal conditions, the recommended counseling is compromised. Indication of treatment requires technical competence and a detailed analysis of ethical issues, and consultation with institutional clinical bioethics services or commissions is important. The article proposes to address the moral conflicts of two clinical cases and the respective bioethical analysis that involves principles and values in contexts of vulnerability and uncertainty, contrasting two situations where the indication of treatment was based on accessibility to treatment.

Growing Heart Valve Implants for Children

The current standard of care for pediatric patients with unrepairable congenital valvular disease is a heart valve implant. However, current heart valve implants are unable to accommodate the somatic growth of the recipient, preventing long-term clinical success in these patients. Therefore, there is an urgent need for a growing heart valve implant for children. This article reviews recent studies investigating tissue-engineered heart valves and partial heart transplantation as potential growing heart valve implants in large animal and clinical translational research. In vitro and in situ designs of tissue engineered heart valves are discussed, as well as the barriers to clinical translation.

Potential of neonatal organ donation and outcome after transplantation

Organ transplantation is limited by access to suitable organs. Infant recipient waitlist mortality is increased due to the scarcity of size-matched organs. Neonatal organ donors have been proposed as an underutilized source of donor organs. However, the literature on the actual prevalence and outcome of neonatal organ donation and transplantation is fragmented and not well analyzed. This literature review aims to summarize the available literature on the potential of neonatal organ donation and to analyze published cases of neonatal organ transplantation. A systematic search of the Medline and Cochrane databases yielded 2964 articles, which were screened for eligibility. In total, 86 articles were considered eligible, of which 34 were included in the literature review: 8 articles describing the potential of neonatal organ donation programs, and 26 articles describing clinical transplantation. Current evidence suggests there is a large pool of potential neonatal organ donors. In contrast, the literature on neonatal organ donor utilization is sparse. However, case series of successful kidney, heart, liver, hepatocyte, and multivisceral transplantation using organs from neonatal donors are summarized. Although good posttransplant organ function was achieved, the use of neonatal organs is associated with increased risk of thrombosis in both kidney and liver transplantation. Neonatal organ donation is a promising alternative for expanding the current donor pool. Experience is limited, but reported patient and graft survival are acceptable and more research on the subject is warranted.

Implementation of a neonatal donation protocol in the neonatal intensive care unit: A single-center experience

BACKGROUND

Lack of specific protocols for neonatal donation contributes to the rarity of neonatal donors. In this study, we evaluate the impact of the implementation of a neonatal donation protocol in our NICU.

METHODS

In this single-center study, we conducted a retrospective chart review of neonatal deaths in our NICU from January 2013 to January 2022. The study was divided into two periods: before and after the implementation of a neonatal donation protocol. The referral rates of potential neonatal donors to the OPO in the two periods were compared using the chi-square test. A p value < .05 was considered statistically significant.

RESULTS

Sixty-four infants were reviewed. Seven (10.9%) met the inclusion criteria for potential neonatal donors after DCC. The referral rate of potential neonatal donors increased from 2.5% to 16.7% after the implementation of this protocol (p = .041), and one infant (4.1%) became an effective heart-valve donor.

CONCLUSION

The implementation of a local neonatal donation protocol could have contributed to increase the referral rate of potential neonatal donors in our NICU. Following the implementation of a local neonatal donation protocol, we were able to perform a heart-valve donation for the first time in our unit.

Pediatric heart transplantation in infants and small children under 3 years of age: Single center experience - "Early and long-term results"

OBJECTIVES

We analyzed the early and long-term survival after ABO-compatible heart transplantation in children under 3 years of age from 1991 to 2021 at our center. This retrospective and descriptive study aimed to identify serious adverse events associated with mortality after pediatric heart transplantation.

PATIENTS AND METHODS

46 patients with congenital heart failure (37%) in end-stage heart failure have undergone a pediatric heart transplantation. Primary outcome of interest was survival at follow-up time.

RESULTS

Median (IQR) follow-up time (y), age (y), body-weight (kg) and BMI (kg/cm²) were 13.2 (5.7-19.5), 0.9 (0.2-2.0), 6.8 (4.3-10.0) and 14.2 (12.3-15.7). Twenty-four (52%) patients were male. 15 patients (33%) had a single ventricle physiology. At 30- days survival rate was 94 ± 4%. Survival rate at 1, 5, 10 and 15 years post HTx was 87 ± 5%, 84 ± 6%, 79 ± 6% and 63 ± 8%. One child underwent re-transplantation after 4 years, and another one after 11 years - in both cases due to graft failure. Higher early mortality in patients under 3 months of age and in patients with single ventricle physiology. Transplant free survival at 15 years was in children with cardiomyopathy better (71 ± 10%) than in those with congenital heart disease (50 ± 13%). One or more previous heart surgeries prior to HTx (n = 21) were associated to more mortality.

CONCLUSION

Pediatric heart transplantation has acceptable long-term results and is still the best therapeutic option in children with end-stage cardiac failure. Underlying anomalies and single ventricle physiology, age below 3 months had a significant impact on survival.

Systemic Venous Reconstructions During Pediatric Heart Transplantation

BACKGROUND

Congenital heart disease continues to be an important indication for pediatric heart transplantation (HT) and is often complicated by systemic venous anomalies. The need for reconstruction, surgical technique used, as well as the outcomes of these have limited documentation.

METHODS

Descriptive, retrospective study of patients transplanted at Emory University between 2006 and 2017. We reviewed surgical data, follow-up, and interventions for patients necessitating venous reconstruction during transplantation.

RESULTS

A total of 179 transplants were performed during the time period of which 74 (41%) required systemic venous reconstruction. Mean age at transplant was 6.3 (±6.16) years, and 74.3% of these patients carried a diagnosis of single ventricle; 51 (68.9%) of 74 patients required pulmonary artery reconstruction at the time of HT. Forty patients required superior vena caval reconstruction, while 22 patients required inferior vena caval reconstruction due to prior palliation or anomaly. Venous anomalies along with other anatomic features necessitated biatrial transplantation in four patients. Posttransplant evaluation revealed systemic venous stenosis in 14 (18.9%) of 74 patients. Eight (10.8%) patients required 12 interventions for the systemic veins. Patients with bilateral Glenn anastomosis prior to transplant were at high risk for the development of stenosis and needing interventions. Systemic venous complications were uncommon in those with native systemic veins without Glenn or Fontan procedure.

CONCLUSION

Systemic venous reconstruction needs are high in pediatric HT. Posttransplant stenosis and the need for interventions are relatively common. Current techniques for systemic venous reconstruction for complex congenital heart disease patients may deserve further review to optimize these outcomes.

Ethical and practical dilemmas in cardiac transplantation in infants: a literature review

The waiting time in infants for a cardiac transplant remains high, due to the scarcity of donors. Consequently, waiting list morbidity and mortality are higher than those in other age groups. Therefore, the decision to list a small infant for cardiac transplantation is seen as an ethical dilemma by most physicians. This review aims to describe outcomes, limitations, and ethical considerations in infant heart transplantation. We used Medline and Embase as data sources. We searched for publications on infant (< 1 year) heart transplantation, bridge-to-transplant and long-term outcomes, and waiting list characteristics from January 2009 to March 2021. Outcome after cardiac transplant in infants is better than that in older children (1-year survival 88%), and complications are less frequent (25% CAV, 10% PTLD). The bridge-to-transplant period in infants is associated with increased mortality (32%) and decreased transplantation rate (43%). This is mainly due to MCS complications or the limited MCS options (with 51% mortality in infancy). Outcomes are worse for infants with CHD or in need of ECMO-support.Conclusion: Infants listed for cardiac transplantation have a high morbidity and mortality, especially in the period between diagnosis and transplantation. For those who receive cardiac transplant, the outlook is encouraging. Unfortunately, despite growing experience in VAD, mortality in children < 10 kg and children with CHD remains high. After transplantation, patients carry a psychological burden and there is a probability of re-transplantation later in life, with decreased outcomes compared to primary transplantation. These considerations are seen as an important ethical dilemma in many centers, when considering cardiac transplantation in infants (< 1 year). What is Known: • For infants, waitlist mortality remains high. In the pediatric population, MCS reduces the waiting list mortality. What is New: • Outcomes after infant cardiac transplantation are better than other age groups; however, MCS options remain limited, with persistently high waiting list mortality. • Future developments in MCS and alternative options to reduce waiting list mortality such as ABO-incompatible transplantation and pulmonary artery banding are encouraging and will improve ethical decision-making when an infant is in need of a cardiac transplant.

Neonatal heart transplant outcomes: A single institutional experience

OBJECTIVE

Neonatal orthotopic heart transplantation was introduced in the 1980s as a treatment for complex congenital heart disease. Progress in single-ventricle palliation and biventricular correction has resulted in a decline in neonatal heart transplant volume. However, limited reports on neonatal heart transplants have demonstrated favorable outcomes. We report the long-term outcomes of patients with neonatal heart transplants at our institution spanning nearly 30 years.

METHODS

A retrospective analysis of neonatal heart transplants and neonates listed for transplant was performed at Children's Hospital Colorado. Primary outcomes were early and late survival. Secondary outcomes were rejection episodes, retransplantation, and development of cardiac allograft vasculopathy or post-transplant lymphoproliferative disease.

RESULTS

A total of 21 neonates underwent orthotopic heart transplantation at our institution. Among these, 10 neonates were transplanted from 1991 to 2000, 8 neonates were transplanted from 2001 to 2010, and 3 neonates were transplanted from 2011 to 2020. The average age of these patients was 17 days, and the average weight was 3.43 kg. Early survival was 95.2%. Survival at 1 and 5 years was 85.7% (confidence interval [CI], 61.9%-95.2%) and 75% (CI, 45.6%-85.5%), respectively. Of eligible patients, the 10-year and 20-year survival was 72.2% (CI, 45.1%-85.3%) and 50% (CI, 25.9%-70.1%), respectively.

CONCLUSIONS

Our institution reports favorable outcomes of neonatal heart transplantation. These results should be considered within the context of outcomes for patients awaiting transplant and the limited donor availability. However, the successful nature of these procedures suggest it may be necessary to reevaluate the indications for neonatal heart transplantation, particularly where risk of mortality and morbidity with palliative or corrective surgery is high.

Neonatal donation: are newborns too young to be recognized?

Neonatal organ and tissue donation is not common practice in the Netherlands. At the same time, there is a transplant waiting list for small size-matched organs and tissues. Multiple factors may contribute to low neonatal donation rates, including a lack of awareness of this option. This study provides insight into potential neonatal organ and tissue donors and reports on how many donors were actually reported to the procurement organization. We performed a retrospective analysis of the mortality database and medical records of two largest neonatal intensive care units (NICUs) in the Netherlands. This study reviewed records of neonates with a gestational age >37 weeks and weight >3000g who died in the period from January 1, 2005 through December 31, 2016. During the study period, 259 term-born neonates died in the two NICUs. In total, 132 neonates with general contra-indications for donation were excluded. The medical records of 127 neonates were examined for donation suitability. We identified five neonates with documented brain death who were not recognized as potential organ and/or tissue donors. Of the remaining neonates, 27 were found suitable for tissue donation. One potential tissue donor had been reported to the procurement organization. In three cases, the possibility of donation was brought up by parents.Conclusion: A low proportion (2%) of neonates who died in the NICUs were found suitable for organ donation, and a higher proportion (12%) were found suitable for tissue donation. We suggest that increased awareness concerning the possibility of neonatal donation would likely increase the identification of potential neonatal donors. What is Known: • There is an urgent need for very small organs and tissues from neonatal donors What is New: • A number of neonates who died in the NICU were suitable organ or/and tissue donors but were not recognized as donors. • Knowledge on neonatal donation possibilities is also important for proper counseling of parents who sometimes inquire for the possibility of organ and tissue donation.

Evidence-based surgical hypothesis: Partial heart transplantation can deliver growing valve implants for congenital cardiac surgery

Children undergoing congenital cardiac surgery often outgrow the valve implants. These children are thus committed to morbid reoperations for successive exchanges of the vavular implants that they have outgrown. Therefore the holy grail of congenital cardiac surgery is a valve implant that grows with the recipient child. Preserved homografts routinely are used as valve implants, but they do not grow as the child grows because they lose viability during preservation. In contrast, pulmonary autografts and pediatric heart transplants grow with the recipient children. Similarly, partial heart transplantation can deliver growing valve implants for congenital cardiac surgery. Temporary immune suppression would only be needed until the partial heart transplant can be exchanged for an adult-sized prosthetic valve in the grown child.