Cardiac transplantation in children with Down syndrome, Turner syndrome, and other chromosomal anomalies: A multi-institutional outcomes analysis

Development of pulmonary hypertension remains a major hurdle to corrective surgery in Down syndrome

Down syndrome is the most common chromosomal abnormality encountered in clinical practice with 50% of them having associated congenital heart disease (CHD). Shunt lesions account for around 75% of all CHDs in Down syndrome. Down syndrome patients, especially with large shunts are particularly predisposed to early development of severe pulmonary hypertension (PH) compared with shunt lesions in general population. This necessitates timely surgical correction which remains the only viable option to prevent long term morbidity and mortality. However, despite clear recommendations, there is wide gap between actual practice and fear of underlying PH which often leads to surgical refusals in Down syndrome even when the shunt is reversible. Another peculiarity is that Down syndrome patients can develop PH even after successful correction of shunt. It is not uncommon to come across Down syndrome patients with uncorrected shunts in adulthood with irreversible PH at which stage intracardiac repair is contraindicated and the only option available is a combined heart-lung transplant. However, despite the guidelines laid by authorities, the rates of cardiac transplant in adult Down syndrome remain dismal largely attributable to the high prevalence of intellectual disability in them. The index case presents a real-world scenario highlighting the impact of severe PH on treatment strategies and discrimination driven by the fear of worse outcomes in these patients.

Cardiovascular Complications of Down Syndrome: Scoping Review and Expert Consensus

Cardiovascular disease is a leading cause of morbidity and mortality in individuals with Down syndrome. Congenital heart disease is the most common cardiovascular condition in this group, present in up to 50% of people with Down syndrome and contributing to poor outcomes. Additional factors contributing to cardiovascular outcomes include pulmonary hypertension; coexistent pulmonary, endocrine, and metabolic diseases; and risk factors for atherosclerotic disease. Moreover, disparities in the cardiovascular care of people with Down syndrome compared with the general population, which vary across different geographies and health care systems, further contribute to cardiovascular mortality; this issue is often overlooked by the wider medical community. This review focuses on the diagnosis, prevalence, and management of cardiovascular disease encountered in people with Down syndrome and summarizes available evidence in 10 key areas relating to Down syndrome and cardiac disease, from prenatal diagnosis to disparities in care in areas of differing resource availability. All specialists and nonspecialist clinicians providing care for people with Down syndrome should be aware of best clinical practice in all aspects of care of this distinct population.

Heart transplantation in children and adults with Down syndrome: A single centre experience

BACKGROUND

In recent years, rapid advances in cardiac surgery and changes in attitude towards patients with cognitive disability have led to these patients receiving cardiac transplantation.

METHOD

This is a retrospective report describing the experience of four patients with Down Syndrome who received heart transplantation in a single institution.

RESULTS

Anthracycline-induced cardiomyopathy was the most common cause of heart failure in this group (3/4). Two patients were bridged to transplantation, one by using a combination of extra-corporeal membrane oxygenation and biventricular assist device and the other by using a durable implantable left ventricular assist device. All the four patients are alive with the longest surviving patient 17 years after transplantation. Against strong hypothetical predictions, we observed no propensity for the development of post-transplant infections or lymphoproliferative disorders.

CONCLUSION

Down Syndrome should not be the sole contraindication to heart transplantation. The decision for transplantation should be on a case-by-case basis provided adequate social support is in place.

Heart Transplantation in Children With Down Syndrome

Background

Children with Down syndrome (DS) have a high risk of cardiac disease that may prompt consideration for heart transplantation (HTx). However, transplantation in patients with DS is rarely reported. This project aimed to collect and describe waitlist and post– HTx outcomes in children with DS.

Methods and Results

This is a retrospective case series of children with DS listed for HTx. Pediatric HTx centers were identified by their participation in 2 international registries with centers reporting HTx in a patient with DS providing detailed demographic, medical, surgical, and posttransplant outcome data for analysis. A total of 26 patients with DS were listed for HTx from 1992 to 2020 (median age, 8.5 years; 46% male). High‐risk or failed repair of congenital heart disease was the most common indication for transplant (N=18, 69%). A total of 23 (88%) patients survived to transplant. All transplanted patients survived to hospital discharge with a median posttransplant length of stay of 22 days. At a median posttransplant follow‐up of 2.8 years, 20 (87%) patients were alive, 2 (9%) developed posttransplant lymphoproliferative disorder, and 8 (35%) were hospitalized for infection within the first year. Waitlist and posttransplant outcomes were similar in patients with and without DS (P=non‐significant for all).

Conclusions

Waitlist and post‐HTx outcomes in children with DS selected for transplant listing are comparable to pediatric HTx recipients overall. Given acceptable outcomes, the presence of DS alone should not be considered an absolute contraindication to HTx.

Mid-Term Outcomes of Heart Transplantation in Children with Genetic Disorders

BACKGROUND

Many congenital heart diseases (CHD) are associated with genetic defects. Children with complex CHD often develop heart failure, requiring heart transplant. Given the broad spectrum of genetic pathologies and dearth of transplants performed in these children, little is known regarding their outcomes.

METHODS

We conducted a retrospective review of heart transplants performed at a high-volume center from 2007-2021. Patients were separated into pathogenic molecular and copy number variants, aneuploidies, and variants of uncertain significance, and compared to those without known genetic diagnoses. Variables included genetic diagnoses, bridge-to-transplant approach, preoperative comorbidities, operative characteristics, and postoperative complications. Outcomes included ICU-free days to 28 days, hospital mortality, survival, rejection, re-transplantation, and educational status at latest follow-up.

RESULTS

223 patients were transplanted over the study period: 9.9% (22/223) had pathogenic molecular variants, 4.5% (10/223) had copy number variants, 1.8% (4/223) had aneuploidies, and 9.0% (20/223) had variants of uncertain significance. The most common anomalies were Turner syndrome (n=3) and 22q11.2 deletion syndrome (n=2). Children with aneuploidies had higher rates of hepatic dysfunction and hypothyroidism, while those with pathogenic copy number variants had higher rates of preoperative gastrostomy and stroke. Children with aneuploidies were intubated longer post-transplant, with greater need for re-intubation, and had the fewest ICU-free days. Mortality and mean survival did not differ. At median follow-up of 4.4 (1.9-8.8) years, 89.7% (26/29) of survivors with pathogenic anomalies were attending or had graduated school.

CONCLUSIONS

Despite more preoperative comorbidities, mid-term outcomes following heart transplant in children with genetic syndromes and disorders are promising.

Inequitable Access to Transplants: Adults With Impaired Decision-Making Capacity

Inequitable access to deceased donor organs for transplantation has received considerable scrutiny in recent years. Emerging evidence suggests patients with impaired decision-making capacity (IDC) face inequitable access to transplantation. The "Ethical and Legal Issues" working group of the European Society of Transplantation undertook an expert consensus process. Literature relating to transplantation in patients with IDC was examined and collated to investigate whether IDC is associated with inferior transplant outcomes and the legitimacy of this healthcare inequality was examined. Even though the available evidence of inferior transplant outcomes in these patients is limited, the working group concluded that access to transplantation in patients with IDC may be inequitable. Consequently, we argue that IDC should not in and of itself be considered as a barrier to either registration on the transplant waiting list or allocation of an organ. Strategies for non-discrimination should focus on ensuring eligibility is based upon sound evidence and outcomes without reference to non-medical criteria. Recommendations to support policy makers and healthcare providers to reduce unintended inequity and inadvertent discrimination are set out. We call upon transplant centres and national bodies to include data on decision-making capacity in routine reporting schedules in order to improve the evidence base upon which organ policy decisions are made going forward.

Prevalence and Long-Term Outcomes of Solid Organ Transplant in Children with Intellectual Disability

OBJECTIVES

To describe the prevalence and long-term outcomes of kidney, liver, and heart transplant for children with an intellectual disability.

STUDY DESIGN

We performed a retrospective cohort analysis of children receiving a first kidney, liver, or heart-alone transplant in the United Network for Organ Sharing dataset from 2008 to 2017. Recipients with definite intellectual disability were compared with those possible/no intellectual disability. Kaplan-Meier survival estimates were calculated for graft and patient survival. Cox proportional hazard models were used to estimate the association between intellectual disability and graft and patient survival.

RESULTS

Over the study period, children with definite intellectual disability accounted for 594 of 6747 (9%) first pediatric kidney-alone, 318 of 4566 (7%) first pediatric liver-alone, and 324 of 3722 (9%) first pediatric heart-alone transplant recipients. Intellectual disability was not significantly associated with patient or graft survival among liver and heart transplant recipients. Among kidney transplant recipients, definite intellectual disability was significantly associated with higher graft survival and lower patient survival, but the absolute differences were small.

CONCLUSIONS

Children with intellectual disability account for 7%-9% of pediatric transplant recipients with comparable long-term outcomes to other pediatric recipients. These findings provide important empirical support for policies that include children with intellectual disability as transplant candidates.

Perioperative care of adults with Down syndrome: a narrative review

Because of enhanced life expectancy due to medical and surgical therapeutic advances, it is estimated that there are more adults than children living with Down syndrome (DS), or trisomy 21, in the United States. Therefore, DS can no longer be considered a syndrome limited to the pediatric population. These patients are presenting for surgery and anesthesia in adult care settings, where anesthesiologists will encounter these patients more frequently. As these patients age, their commonly associated co-morbidities not only progress, but they also develop other cardiac, respiratory, gastrointestinal, and neurologic conditions. The manifestations and consequences of chronic disease can present new challenges for the anesthesiologist and require expertise and judgement to minimize patient risk. The purpose of this narrative review is to describe the common pediatric co-morbidities associated with DS and discuss the age-acquired manifestations. Additionally, considerations for anesthetic care of the adult with DS will be presented, including the preoperative assessment, intraoperative management, and postoperative care.

Down syndrome and congenital heart disease: perioperative planning and management

Approximately 50% of newborns with Down syndrome have congenital heart disease. Non-cardiac comorbidities may also be present. Many of the principles and strategies of perioperative evaluation and management for patients with congenital heart disease apply to those with Down syndrome. Nevertheless, careful planning for cardiac surgery is required, evaluating for both cardiac and noncardiac disease, with careful consideration of the risk for pulmonary hypertension. In this manuscript, for children with Down syndrome and hemodynamically significant congenital heart disease, we will summarize the epidemiology of heart defects that warrant intervention. We will review perioperative planning for this unique population, including anesthetic considerations, common postoperative issues, nutritional strategies, and discharge planning. Special considerations for single ventricle palliation and heart transplantation evaluation will also be discussed. Overall, the risk of mortality with cardiac surgery in pediatric patients with Down syndrome is no more than the general population, except for those with functional single ventricle heart defects. Underlying comorbidities may contribute to postoperative complications and increased length of stay. A strong understanding of cardiac and non-cardiac considerations in children with Down syndrome will help clinicians optimize perioperative care and long-term outcomes.

Genetic disease and intellectual disability as contraindications to transplant listing in the United States: A survey of heart, kidney, liver, and lung transplant programs

Discrimination based on disability is prohibited in organ transplantation, yet studies suggest it continues in listing practices for intellectual disability and genetic diseases. It is not known if this differs between adult and pediatric programs, or by organ type. We performed an online, forced-choice survey of psychosocial listing criteria for adult and pediatric heart, kidney, liver, and lung transplant programs in the United States. Of 650 programs contacted, 343 (52.8%) submitted complete. A minority of programs had formal listing guidelines for any condition considered (Down Syndrome, Duchenne Muscular Dystrophy, Becker Muscular Dystrophy, DiGeorge Syndrome, and Wolf Hirschhorn Syndrome; and mild [IQ < 70] and severe [IQ < 35] intellectual disability), although a majority had encountered most. Pediatric programs were significantly (P < .02) more lenient in the level of contraindication to listing for all genetic conditions considered except Duchenne Muscular Dystrophy, and for mild and severe intellectual disability. Level of contraindication differed significantly by organ type (heart, lung, liver, and kidney) for Duchenne Muscular dystrophy (P = <.001), Becker Muscular Dystrophy (P < .001), DiGeorge Syndrome (P < .001), Wolf-Hirschhorn syndrome (P = .0012), and severe intellectual disability (P < .001). There is significant variation among transplant programs in availability of guidelines for as well as listing practices regarding genetic diseases and intellectual disability, differing by both adult vs pediatric program, and organ type. Programs with absolute contraindications to listing for specific genetic diseases or intellectual disability should reframe their approach, ensuring individualized assessments and avoiding elimination of patients based on membership in a particular group.

Heart transplantation in an infant with Williams-Beuren syndrome and rapidly progressive ischemic cardiomyopathy

Ischemic cardiomyopathy with resultant refractory HF may occur in patients with WBS, often as the result of coronary involvement with SVAS. The rapid development of arteriopathy at a young age raises concerns regarding transplant candidacy due to progressive stenoses at other arterial sites with potential detrimental impact on long-term heart graft function. We report a 2-month-old male infant diagnosed with mild aortic stenosis during the neonatal period, but subsequently developed rapidly progressive supravalvar and coronary artery stenoses leading to cardiogenic shock due to myocardial ischemia. The presentation led to the diagnosis of WBS. He required prolonged CPR including ECMO therapy. He subsequently underwent LVAD implantation as bridge to transplant and 4 days later heart transplantation. His post-operative course was complicated by prolonged mechanical ventilation and extended intensive care unit and hospital stays. However, at follow-up 18 months post-transplant he continues to have normal graft function with mild, non-progressive residual coarctation of aorta and non-progressive moderately hypoplastic pulmonary arteries.

Pediatric waitlist and heart transplant outcomes in patients with syndromic anomalies

PURPOSE

We sought to determine whether the presence of a systemic SA with potential complicating factors affects waitlist and post-HT outcomes in pediatric patients.

METHODS

This is a single-center retrospective review of pediatric patients listed for HT between January 1, 2009, and July 1, 2018. Patients were selected based on the presence of any underlying syndromes, which included chromosomal anomalies, skeletal myopathies, connective tissue disorders, mitochondrial disease,and other systemic disorders. Waitlist and post-HT outcomes were compared to those without SA.

RESULTS

A total of 243 patients were listed for HT, of which 21 (9%) patients had associated SA. Of those, 16 (76%) survived to transplant, 3 (14%) died while on the waitlist, 1 (5%) improved and was removed from the waitlist, and 1 (5%) patient is currently listed. Waitlist survival was not different between those with/without an associated syndrome (P = 1.0). Among those who survived to HT, there was no difference in listing days (70 vs 90, P = .8), survival to hospital discharge [14 (93%) vs 150 (95%), P = .6], post-HT intubation days (2 vs 2 days, P = .6), or post-HT hospital length of stay (18 vs 18 days, P = .8). Overall survival during the study period post-HT was not different between groups (P = .8).

CONCLUSION

A SA was present in 9% of pediatric patients wait-listed for HT, but was not associated with an increased waitlist mortality or post-HT hospital morbidity or long-term survival. For several anomalies, HT is safe and feasible.

Characteristics and Outcomes of Heart Transplantation in DiGeorge Syndrome

DiGeorge syndrome (DGS) is commonly associated with both congenital heart disease (CHD) and immunologic abnormalities. While CHD may prompt consideration for heart transplantation (HTx), little is known about HTx management or outcomes in this group. The aim of this study was to describe the spectrum of patients with DGS who undergo HTx and report post-HTx outcomes. All pediatric HTx recipients (2002-2016) with DGS were identified using ICD codes from a linked billing and clinical registry database. Patient characteristics and outcomes were described and compared to non-DGS HTx recipients with CHD. Kaplan-Meier methods were used to assess overall survival, freedom from infection, and freedom from rejection. A total of 17 patients with DGS who underwent HTx at 12 different centers were included. Median age at HTx was 5 years (IQR 0-13 years). Steroids were used for induction in all patients in addition to thymoglobulin in 13/17 (76%) and IL2R antagonists in 3/17 (18%). Maintenance immunosuppression was a combination of tacrolimus or cyclosporine and mycophenolate or azathioprine in 16/17 (94%). Half received steroids at the time of discharge. There were six deaths (35%). The median post-HTx survival was 5.4 years with no difference in freedom from rejection, infection, or overall survival between patients with and without DGS. Patients with DGS undergoing HTx received standard immunosuppression. We found no difference in freedom from infection, rejection, or overall post-HTx survival compared to non-DGS patients, although the small size of our study resulted in limited statistical power. Given the potential for favorable outcomes, patients with DGS may be considered for HTx in the appropriate clinical setting.

Cardiovascular disease in Down syndrome

PURPOSE OF REVIEW

In the last 40 years, with a better understanding of cardiac defects, and with the improved results of cardiac surgery, the life expectancy of persons with Down syndrome has significantly increased. This review article reports on advances in knowledge of cardiac defects and cardiovascular system of persons with trisomy 21.

RECENT FINDINGS

New insights into the genetics of this syndrome have improved our understanding of the pathogenetic mechanisms of cardiac defects. Recent changes in neonatal prevalence of Down syndrome suggest a growing number of children with cardiac malformations, in particular with simple types of defects. Ethnic and sex differences of the prevalence of specific types of congenital heart disease (CHD) have also been underlined. A recent study confirmed that subclinical morphologic anomalies are present in children with trisomy 21, also in the absence of cardiac defects, representing an internal stigma of Down syndrome. The results of cardiac surgery are significantly improved in terms of immediate and long-term outcomes, but specific treatments are indicated in relation to pulmonary hypertension. Particular aspects of the cardiovascular system have been described, clarifying a reduced sympathetic response to stress but also a 'protection' from atherosclerosis and arterial hypertension in these patients.

SUMMARY

Continuing dedication to clinical and basic research studies is essential to further improve survival and the quality of life from childhood to adulthood of patients with trisomy 21.