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

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.

Reality of DCD donor use in pediatric thoracic transplantation in the United States

In the US, the first pediatric donation after circulatory death (DCD) thoracic transplant was done in 2004; however, ethical controversy led to minimal utilization of these donors. The present study was performed to characterize the current state of pediatric DCD heart and lung transplantation (HTx, LTx). Children (<18 year old) who underwent HTx or LTx using DCD donors from June 2004 to June 2022 were identified in the United Network for Organ Sharing registry. A total of 14 DCD recipients were identified: 7 (50%) HTx and 7 (50%) LTx. Donor and recipient demographics are described in Table 1. One and 5-year post-transplant survival were as follows: HTx recipients (64% for each) and LTx recipients (86%, 55%). Although often discussed, the national experience with DCD donors for pediatric HTx and LTx remains limited and not being practiced consistently by any pediatric program. Given the critical organ shortage, DCD use in the field of pediatric thoracic transplantation should be strongly considered.

Donor hyperoxia is a novel risk factor for severe cardiac primary graft dysfunction

BACKGROUND

Primary graft dysfunction (PGD) is a major cause of early mortality following heart transplant (HT). Donor risk factors for the development of PGD are incompletely characterized. Donor management goals (DMG) are predefined critical care endpoints used to optimize donors. We evaluated the relationship between DMGs as well as non-DMG parameters, and the development of PGD after HT.

METHODS

A cohort of HT recipients from 2 transplant centers between 1/1/12 and 12/31/19 was linked to their respective donors in the United Network for Organ Sharing (UNOS) DMG Registry (n = 1,079). PGD was defined according to modified ISHLT criteria. Variables were subject to univariate and multivariable multinomial modeling with development of mild/moderate or severe PGD as the outcome variable. A second multicenter cohort of 4,010 donors from the DMG Registry was used for validation.

RESULTS

Mild/moderate and severe PGD occurred in 15% and 6% of the cohort. Multivariable modeling revealed 6 variables independently associated with mild/moderate and 6 associated with severe PGD, respectively. Recipient use of amiodarone plus beta-blocker, recipient mechanical circulatory support, donor age, donor fraction of inspired oxygen (FiO₂), and donor creatinine increased risk whereas predicted heart mass ratio decreased risk of severe PGD. We found that donor age and FiO₂ ≥ 40% were associated with an increased risk of death within 90 days post-transplant in a multicenter cohort.

CONCLUSIONS

Donor hyperoxia at heart recovery is a novel risk factor for severe primary graft dysfunction and early recipient death. These results suggest that excessive oxygen supplementation should be minimized during donor management.

A Neonatal ABO non-compatible heart transplant from a circulatory-determined death donor using NRP/Cold storage

BACKGROUND

Donation after Circulatory death is gaining worldwide acceptance. Most protocols regard their first cases to be performed with donor and recipient in the same institution. Few records of children or distant procurement have been published.

METHODS

Our institution was offered a heart from a 3-day-old, 3.4-kg child, blood group A, suffering irreversible encephalopathy. Parents accepted withdrawal of life-sustaining therapy and agreed to donation. The donor hospital was located 340 km away. Concomitantly, a 2-month-old, 3.1 kg, blood group type B and with non-compaction ventricles was awaiting for the heart transplant in our unit.

RESULTS

Thirty-seven minutes after withdrawal of life-sustaining therapy, the heart arrested. Five minutes afterwards, a sternotomy was performed. The supra-aortic vessels were clamped altogether. Aorta and right appendage were cannulated and connected to heart-lung machine. The innominate artery above the clamp was severed. The heart resumed spontaneous rhythm in less than 1 min. Ventilation was restored and extracorporeal circulation was maintained for 32 min. Upon cardiologic arrest, the graft was harvested as routinely. The heart was cold-stored and transported by plane to our Hospital. An orthotopic bicaval transplant was performed. Overall cold ischaemia was 245 min. Ten weeks later, the child was discharged home in good condition.

CONCLUSION

Donation in circulatory death could increase the pool in neonates. Extracorporeal circulation proves successful for procurement in neonates. Distant procurement plus cold storage for donation in circulatory death is feasible. Donation in circulatory death and ABO non-compatible strategies are complementary to each other.

Donation After Circulatory Death: A New Frontier

PURPOSE OF REVIEW

To highlight the current global experience with DCD heart transplantation and explore the evolution of, and compare preservation strategies; examine early clinical outcomes, and discuss the growing use of DCD donors as a new frontier in heart transplantation.

RECENT FINDINGS

The two strategies of DCD heart preservation include NMP using the OCS Heart and TA-NRP followed by either: NMP or CSS. Better understanding the limits of cold ischaemia following TA-NRP will aid in distant procurement. Asystolic warm ischaemia plays an important role in determining immediate post-operative graft function and potential need for mechanical support. Large volume DCD heart transplant units show no difference in survival between DCD and DBD donor heart transplants. In a previously non-utilised source of donor hearts, often viewed as an "unknown frontier" in heart transplantation, DCD hearts are a suitable alternative to brain-dead donor hearts and are likely to remain a permanent part of the heart transplantation landscape. Global uptake is currently increasing, and as understanding of preservation strategies and tolerable ischaemic times improve, utilisation of DCD hearts will continue to grow.

Expanding Donor Heart Utilization Through Machine Perfusion Technologies

Purpose of Review

Recent advances in donor heart preservation have allowed the utilization of hearts that would typically be discarded due to prolonged ischemic times or donation via the circulatory death pathway. This review will discuss recent advances in donor heart preservation including optimization of machine perfusion technologies and future strategies of potential benefit for the donor heart and transplant outcomes.

Recent Findings

Improvements in organ preservation strategies have enabled retrieval of donor hearts that were not ideal for static cold storage. Machine perfusion (normothermic and hypothermic) and normothermic regional perfusion have ultimately expanded the donor pool for adult heart transplantation. Xenotransplantation has also incorporated machine perfusion for porcine donor heart preservation.

Summary

Traditional static cold storage is feasible for non-complex donors and transplants. Machine perfusion has enabled increased donor heart utilization however optimal preservation strategies are dependent on the donor criteria, predicted ischemic times and surgical complexity.

Normothermic Ex Situ Heart Perfusion With the Organ Care System for Cardiac Transplantation: A Meta-analysis

BACKGROUND

Heart transplantation (HTx) is, at present, the most effective therapy for end-stage heart failure patients; however, the number of patients on the waiting list is rising globally, further increasing the gap between demand and supply of donors for HTx. First studies using the Organ Care System (OCS) for normothermic machine perfusion show promising results yet are limited in sample size. This article presents a meta-analysis of heart donation either after brain death (OCS-DBD) or circulatory death (OCS-DCD) on using OCS versus static cold storage used for HTx.

METHODS

A systematic literature search was performed for articles discussing the use of normothermic ex situ heart perfusion in adult patients. Thirty-day survival outcomes were pooled, and odds ratios were calculated using random-effects models. Long-term survival was visualized with Kaplan-Meier curves, hazard ratios were calculated and pooled using fixed-effects models, and secondary outcomes were analyzed.

RESULTS

A total of 12 studies were included, with 741 patients undergoing HTx, of which 260 with the OCS (173 DBD and 87 DCD). No differences were found between the 3 groups for early and late survival outcomes or for secondary outcomes.

CONCLUSIONS

OCS outcomes, for both DBD and DCD hearts, appeared similar as for static cold storage. Therefore, OCS is a safe and effective technique to enlarge the cardiac donor pool in both DBD and DCD, with additional benefits for long-distance transport and surgically complex procedures.

Heart Donation From Donors After Controlled Circulatory Death

The gold-standard therapy for advanced-stage heart failure is cardiac transplantation. Since the first heart transplant in 1967, the majority of hearts transplanted came from brain death donors. Nevertheless, in recent years, the option of donation after circulatory death (DCD) is gaining importance to increase donor pool. Currently, heart-transplant programs using controlled donation after circulatory death (cDCD) have been implemented in the United Kingdom, Belgium, Australia, United States of America, and, recently, in Spain. In this article, we performed a concise review of the literature in heart cDCD; we summarize the pathophysiology involved in ischemia and reperfusion injury during this process, the different techniques of heart retrieval in cDCD donors, and the strategies that can be used to minimize the damage during retrieval and until transplantation. Heart transplant using DCD hearts is in continuous improvement and must be implemented in experienced cardiac transplant centers.

Heart transplantation following donation after circulatory death: Expanding the donor pool

Heart transplantation from donation after circulatory death (DCD) donors is a rapidly expanding practice. In this review, we describe the history and challenges of DCD heart transplantation and overview the procurement protocols and methods of limiting ischemic injury, current outcomes, and future directions. There are now at least three protocols that permit resuscitation and viability assessment of the DCD heart either in situ or ex situ. While the retrieval protocol for hearts from DCD donors will depend on local regulations, the outcomes of DCD heart transplant recipients reported to date are excellent regardless of the retrieval protocol and are comparable to the outcomes of heart transplant recipients from donation after brain death (DBD) donors. In the two centers with the largest published experience, DCD heart transplantation now accounts for one third of their heart transplant activity. With international trends indicating that there is an increasing utilisation of the DCD pathway, it is expected that DCD donors will become a major source of heart donation worldwide.

Transplantation of donor hearts after circulatory death using normothermic regional perfusion and cold storage preservation

OBJECTIVES

Hearts donated after circulatory determination of death are usually preserved with normothermic machine perfusion prior to transplantation. This type of preservation is costly, requires bench time adding to warm ischaemia, and does not provide a reliable evaluation of the unloaded donor heart. We report on 4 successful donation after circulatory death (category III) hearts transplanted after thoraco-abdominal normothermic regional perfusion (NRP) and static cold storage.

METHODS

After life sustaining therapy was withdrawn and death was declared, perfusion to thoraco-abdominal organs was restored using extracorporeal circulation via cannulas in the femoral artery and vein and clamping of supra-aortic vessels. After weaning from extracorporeal circulation, cardiac function was assessed. Once approved, the heart was retrieved and stored using classic static cold storage. Data are expressed as median [min-max].

RESULTS

Donor and recipient ages were 44 years [12-60] (n = 4) and 53 years [14-64] (n = 4), respectively. Time from the withdrawal of life sustaining therapy to start of NRP was 22 min [18-31]. Cold storage time was 72 min [35-129]. Thirty-day survival was 100% with a left ventricle ejection fraction of 60% [50-60].

CONCLUSIONS

Donation after circulatory death heart transplantation using thoraco-abdominal NRP and subsequent cold storage preservation for up to 129 min was safe for 4 procedures and could be a way to expand the donor heart pool while avoiding costs of machine preservation.

DCD donations and outcomes of heart transplantation: the Australian experience

Purpose

There is increasing clinical utilization of hearts from the donation after circulatory death (DCD) pathway with the aim of expanding the donor pool and mitigating the ever-present discrepancy between the inadequate availability of good quality donor hearts and the rising number of patients with end-stage heart failure.

Methods

This article reviews the rationale, practice, logistical factors, and 5-year experience of DCD heart transplantation at St Vincent's Hospital, Sydney.

Findings

Between July 2014 and July 2019, 69 DCD donor retrievals were undertaken resulting in 49 hearts being instrumented on an ex situ normothermic cardiac perfusion device. Seventeen (35%) of these hearts were declined and the remaining 32 (65%) were used for orthotopic DCD heart transplantation. At 5 years of follow-up, the 1-, 3-, and 5-year survival was 96%, 94%, and 94% for DCD hearts compared with 89%, 83%, and 82% respectively for donation after brain death (DBD) hearts (n.s). The immediate post-implant requirement for temporary extra-corporeal membrane oxygenation (ECMO) support for delayed graft function was 31% with no difference in rejection rates when compared with the contemporaneous cohort of patients transplanted with standard criteria DBD hearts.

Summary

DCD heart transplantation has become routine and incorporated into standard clinical practice by a handful of pioneering clinical transplant centres. The Australian experience demonstrates that excellent medium-term outcomes are achievable from the use of DCD hearts. These outcomes are consistent across the other centres and consequently favour a more rapid and wider uptake of heart transplantation using DCD donor hearts, which would otherwise be discarded.

Review of the discard and/or refusal rate of offered donor hearts to pediatric waitlisted candidates

We aimed to review current literature on the discard rate of donor hearts offered to pediatric recipients and assess geographical differences. Consequences and ways to reduce the discard rate are discussed. A systemic review on published literature on pediatric transplantation published in English since 2010 was undertaken. Additionally, a survey was sent to international OPOs with the goal of incorporating responses from around the world providing a more global picture. Based on the literature review and survey, there is a remarkably wide range of discard and/or refusal for pediatric hearts offered for transplant, ranging between 18% and 57% with great geographic variation. The data suggest that that the overall refusal rate may have decreased over the last decade. Reasons for organ discard were difficult to identify from the available data. Although the refusal rate of pediatric donor hearts seems to be lower compared to that reported in adults, it is still as high as 57% with geographic variation.

Pediatric cardiac waitlist mortality-Still too high

Cardiac transplantation for children with end-stage cardiac disease with no other medical or surgical options is now standard. The number of children in need of cardiac transplant continues to exceed the number of donors considered "acceptable." Therefore, there is an urgent need to understand which recipients are in greatest need of transplant before becoming "too ill" and which "marginal" donors are acceptable in order to reduce waitlist mortality. This article reviewed primarily pediatric studies reported over the last 15 years on waitlist mortality around the world for the various subgroups of children awaiting heart transplant and discusses strategies to try to reduce the cardiac waitlist mortality.

Heart transplantation from donation after circulatory death donors: Present and future

The first successful human heart transplantation was reported on 3 December 1967, by Christiaan Barnard in South Africa. Since then this life-saving procedure has been performed in over 120 000 patients. A limitation to the performance of this procedure is the availability of donor hearts with as many as 20% of patients dying before a donor's heart is available for transplant. Today, hearts for transplantation are procured from individuals experiencing donation after brain death (DBD). Interestingly, this, however, was not always the case as the first heart transplants occurred after circulatory death. Revisiting the availability of hearts for transplant from those experiencing donation after circulatory death (DCD) could further expand the number of hearts suitable for transplantation. There are several considerations pertinent to transplanting hearts from those undergoing circulatory death. In this review, we summarize the main distinctions between DBD and DCD heart donation and discuss the research relevant to increasing the number of hearts available for transplantation by including individual's hearts that experience circulatory death.

Flow-targeted pediatric ex vivo heart perfusion in donation after circulatory death: A porcine model

BACKGROUND

The optimal blood flow and pressure to perfuse pediatric hearts from donation after circulatory death (DCD) on the ex vivo perfusion system has not been elucidated. This study sought to investigate the optimal perfusion strategy for pediatric DCD hearts by using a juvenile porcine model comparing pressure- vs flow-targeted strategy.

METHODS

The hearts of the juvenile DCD pigs were explanted, and the coronary arteries were perfused for 2 hours by the ex vivo heart perfusion system with 2 different perfusion strategies; pressure-targeted perfusion (target coronary perfusion pressure: 40 mm Hg, group A) and flow-targeted perfusion (target coronary perfusion flow: 10 ml/kg/min, group B). The working model heart perfusion was used to assess systolic and diastolic myocardial performance.

RESULTS

The body weight, warm and cold ischemic time, and ex vivo perfusion time were comparable between the groups. In the working model, group B showed significantly preserved cardiac output (A: 70.5 ± 15.3 ml/kg/min vs B: 113.8 ± 15.0 ml/kg/min, p < 0.01), stroke volume (A: 0.4 ± 0.1 ml/kg vs B: 0.7 ± 0.1 ml/kg, p < 0.01), and ejection fraction (A: 18.8% ± 5.9% vs B: 35.0% ± 10.6%, p < 0.01). E/e' and Tei index were also significantly preserved in group B. The percentage gain of heart weight after ex vivo (net increase of the heart weight divided by heart weight at baseline) was significantly smaller in group B (A: 20.0% ± 5.3% vs B: 11.6% ± 5.0%, p < 0.05). Troponin-I, myocardial hemorrhage, oxidative stress markers; myeloperoxidase and 8-hydroxy-2'-deoxyguanosine were also significantly lower after ex vivo perfusion in group B (p < 0.05).

CONCLUSIONS

The tightly controlled flow-targeted myocardial perfusion strategy for DCD donor hearts achieved better myocardial performance by causing less myocardial edema and limiting myocardial reperfusion injury.

Paediatric heart transplantation: an update

Heart transplantation is a standard treatment for selected paediatric patients with end-stage heart disease. With improvement in surgical techniques, organ procurement and preservation strategies, immunosuppressive drugs, and more sophisticated monitoring strategies, survival following transplantation has increased over time. However, rejection, infection, renal failure, post-transplant lymphoproliferative disease and post-transplant cardiac allograft vasculopathy still preclude long-term survival. Therefore, continued multidisciplinary scientific efforts are needed for future gains. This review focuses on the current status, outcomes and ongoing challenges including patient selection, indications and contraindications, national and international survivals, post-transplant complications and quality of life.

First report of a successful pediatric heart transplantation from donation after circulatory death with distant procurement using normothermic regional perfusion and cold storage

Heart transplantation (HT) from donation after circulatory death (DCD) is a promising alternative to expand the heart donor pool. Cold storage can be used in a strategy to successfully retrieve and transplant DCD hearts after reconditioning using normothermic regional perfusion for distant procurement. Herein, we present the first report of a pediatric DCD heart reconditioned with normothermic regional perfusion, preserved using only cold storage while being transported to a neighboring center, and then successfully transplanted after nearly 2 hours of cold static storage. If supported by an appropriate trial, this finding could obviate the need to use expensive perfusion devices for short interhospital distances for DCD heart transportation and stimulate more centers across the world to embrace DCD HT.

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.

Development of a multinational registry of pediatric deceased organ donation activity

BACKGROUND

There are no currently agreed upon international standards for reporting of pediatric deceased organ donation activity. This leads to difficulty in comparisons between jurisdictions for both researchers and policy stakeholders. The goal of this project was to develop and test a standardized registry for pediatric deceased donation activity.

METHODS

Four countries (Canada, Spain, USA, and the UK) with geographical and practice diversity were approached to participate. Iterative exchanges were used to create data fields and definitions that were acceptable to all participants. Data from 2011 to 2015 (inclusive) were requested from national health databases and analyzed on a secure, web-based survey platform.

RESULTS

Data were obtained from three of the four countries (Canada unable to provide). Total pediatric donation rates were stable over the 5-year period, but with variation between countries. pDCD rates were the most variable, representing 32.2% of total pediatric donation in the UK, 14.4% in the United States, and 2.6% in Spain during the studied period. Most organs from pediatric donors were allocated to adult recipients, though the rates of allocation of pediatric kidneys to pediatric recipients ranged from 7% in the United States to 40% in Spain.

DISCUSSION

In this limited cohort of three countries, we demonstrated substantial variation in pediatric donation rates and practice. These data highlight opportunities for practice improvement such as the development of rigorous clinical practice guidelines. Future development of this registry will seek to engage more countries, and address barriers that prevented full participation of approached jurisdictions.

Pediatric donation after circulatory determination of death (pDCD): A narrative review

Pediatric donation after circulatory death (pDCD) is an established pathway for organ donation. It remains, however, a relatively rare event worldwide, and most clinicians outside of the pediatric intensive care unit (PICU) are unfamiliar with it. The goal of this review is to introduce the processes and concepts of pDCD. While most children die in circumstances that would not allow pDCD, many children that die after withdrawal of life sustaining therapy (WLST) may be eligible for donation of some organs. The potential benefits of this practice to patients on the wait list are well known, but donation can also be an opportunity to honor a patient's or family's desire to altruistically improve the lives of others. Offering the possibility of donation requires careful attention to ethical principles to ensure that conflicts of interest are avoided and that the family is free to make an independent, fully informed decision. Doing so allows families and decision makers the autonomy to decide if donation is something they wish to incorporate into end-of-life care.

Organ Donation Following Neurologic and Circulatory Determination of Death

OBJECTIVES

To describe important considerations during the process of caring for critically ill children who may be potential organ donors and supporting the family during the death of their child.

DESIGN

Literature review and expert commentary.

MEASUREMENT AND MAIN RESULTS

Medical literature focusing on pediatric donation, best pediatric donation practices, donor management, and factors influencing donation were reviewed. Additional pediatric data were obtained and reviewed from the U.S. Organ Procurement and Transplantation Network. Achieving successful organ donation requires the coordinated efforts of the critical care team, organ donation organization, and transplant team to effectively manage a potential donor and recover suitable organs for transplantation. Collaboration between these teams is essential to ensure that all potential organs are recovered in optimal condition, to reduce death and morbidity in children on transplantation waiting lists as well as fulfilling the family's wishes for their dying child to become a donor.

CONCLUSIONS

Organ donation is an important component of end-of-life care and can help the healing process for families and medical staff following the death of a child. The process of pediatric organ donation requires healthcare providers to actively work to preserve the option of donation before the death of the child and ensure donation occurs after consent/authorization has been obtained from the family. Medical management of the pediatric organ donor requires the expertise of a multidisciplinary medical team skilled in the unique needs of caring for children after neurologic determination of death and those who become donors following circulatory death after withdrawal of life-sustaining medical therapies.