Statin therapy is not associated with improved outcomes after heart transplantation in children and adolescents

Adult and late adolescent complications of pediatric solid organ transplantation

BACKGROUND

There have been over 51 000 pediatric solid organ transplants since 1988 in the United States alone, leading to a growing population of long-term survivors who face complications of childhood organ failure and long-term immunosuppression.

AIMS

This is an educational review of existing literature.

RESULTS

Pediatric solid organ transplant recipients are at increased risk for risk for cardiovascular and kidney disease, skin cancers, and growth problems, though the severity of impact may vary by organ type. Pediatric recipients often are able to complete schooling, maintain a job, and form family and social networks in adulthood, though at somewhat lower rates than the general population, but face additional challenges related to neurocognitive deficits, mental health disorders, and discrimination.

CONCLUSIONS

Transplant centers and research programs should expand their focus to include long-term well-being. Increased collaboration between pediatric and adult transplant specialists will be necessary to better understand and manage long-term complications.

Uncertain benefit of statins in pediatric heart transplant recipients: A PHTS analysis

BACKGROUND

Cardiac allograft vasculopathy (CAV) is a leading cause of graft failure in pediatric heart transplant recipients (HTRs). Early statin use has been shown to reduce CAV incidence and all-cause mortality in adult HTRs. We sought to evaluate the contemporary prevalence and trends of statin use in pediatric HTRs and the association between statin use with CAV development and graft failure.

METHODS

Patients aged <17 years at the time of primary heart transplant who survived to ≥3 years without CAV were identified from the Pediatric Heart Transplant Society database (2001-2018). Statin use in the first 3 years posttransplant was defined as consecutive, intermediate, or absent. Kaplan-Meier survival, multivariable modeling, and propensity score-matched analyses evaluated associations between statin use and CAV incidence and graft survival, with subanalyses performed on subjects aged ≥10 years at transplant.

RESULTS

Among 3,485 (of which 1,086 aged ≥10 years) HTRs, 584 (17%) received consecutive statin therapy, 647 (19%) received intermediate use, and 2,254 (65%) received no statin therapy. Statin use varied widely between sites, with increasing use in the ≥10-year-old cohort over time. By multivariate analysis, statin use was not associated with graft loss. Consecutive statin use was also not associated with graft survival or freedom from CAV development when compared to absent statin use in unmatched or propensity-matched analyses.

CONCLUSIONS

While statins remain commonly utilized in pediatric HTRs, early consecutive statin therapy did not decrease CAV incidence or graft loss. The differing effects of statins on CAV development and progression in pediatric vs adult HTRs suggest differing risk and mediating factors and require further study.

Cardiac allograft vasculopathy and survival in pediatric heart transplant recipients transitioned to adult care

BACKGROUND

Cardiac allograft vasculopathy (CAV) is an important cause of mortality after pediatric heart transplantation (HT) but there is a paucity of data regarding its incidence and impact on survival in pediatric recipients transitioned to adult care.

METHODS

We conducted a retrospective review of consecutive pediatric HT patients from 1989 to 2017 at the Hospital for Sick Children who transitioned to adult care at ≥18 years at Toronto General Hospital. We evaluated the incidence of International Society of Heart and Lung Transplantation CAV grade ≥1 using competing risk models. We assessed the association between all-cause mortality and CAV using Cox proportional hazards and used Kaplan Meier methods to evaluate all-cause mortality stratified by CAV and transplant era (1989-2001, 2002-2017).

RESULTS

Ninety-six patients were transitioned to adult care by January 2022, of which 53 underwent repeat coronary angiography as adults. CAV was newly diagnosed in 49% patients after transition to adult care. The overall incidence of CAV was 3.9 cases per 100 person-years. There was no difference in the adjusted incidence of CAV according to transplant era (subdistribution hazard ratios = 1.17, 95% confidence interval (CI) 0.54-2.66). CAV was associated with a higher risk of death in the early era (hazard ratio (HR) 10.29, 95% CI 2.16-49.96), but not in the recent era (HR 1.61, 95% 0.35-7.47).

CONCLUSIONS

There is a role for continued CAV surveillance after the transition to adult care. The implications of diagnosing CAV after the transition to adult care require further study, particularly because the risk of death in pediatric HT recipients diagnosed with CAV in the more recent era may be attenuated compared to the earlier HT era.

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.

Statins-Beyond Their Use in Hypercholesterolemia: Focus on the Pediatric Population

Statins are a class of medications primarily used in adults to lower cholesterol levels and reduce the risk of cardiovascular events. However, the use of statins in children is generally limited and carefully considered despite the well-documented anti-inflammatory, anti-angiogenic, and pro-apoptotic effects, as well as their effect on cell signaling pathways. These multifaceted effects, known as pleiotropic effects, encompass enhancements in endothelial function, a significant reduction in oxidative stress, the stabilization of atherosclerotic plaques, immunomodulation, the inhibition of vascular smooth muscle proliferation, an influence on bone metabolism, anti-inflammatory properties, antithrombotic effects, and a diminished risk of dementia. In children, recent research revealed promising perspectives on the use of statins in various conditions including neurological, cardiovascular, and oncologic diseases, as well as special situations, such as transplanted children. The long-term safety and efficacy of statins in children are still subjects of ongoing research, and healthcare providers carefully assess the individual risk factors and benefits before prescribing these medications to pediatric patients. The use of statins in children is generally less common than in adults, and it requires close monitoring and supervision by healthcare professionals. Further research is needed to fully assess the pleiotropic effects of statins in the pediatric population.

Clinical approach to antibody-mediated rejection from the pediatric heart transplant society

This document is designed to outline the definition, pathogenesis, diagnostic modalities and therapeutic measures to treat antibody-mediated rejection in children postheart transplant METHODS: Literature review was conducted by a Pediatric Heart Transplant Society (PHTS) working group to identify existing pediatric and adult studies on antibody-mediated rejection (AMR). In addition, the centers participating in PHTS were asked to submit their approach to diagnosis and management of pediatric AMR. This document synthesizes information gathered from both these sources to highlight a practical approach to diagnosing and managing a child with AMR postheart transplant. This document may not represent the practice at all centers in the PHTS and serves as a starting point to understand an approach to this clinical scenario.

Cardiac allograft vasculopathy: A review

BACKGROUND

Heart transplantation has become the standard of care for pediatric patients with end-stage heart disease, and outcomes have consistently improved over the last few decades. CAV, however, remains a leading cause of morbidity and mortality in heart transplantation and is the leading cause of death beyond 3 years post-transplantation. We sought out to provide an in-depth overview of CAV in the pediatric heart transplant population.

METHODS

Database searches were conducted in both Medline and Embase on the topic of cardiac vasculopathy in pediatric heart transplant recipients. The search used five broad concept terms: heart transplant; pediatric; CAV; diagnosis, prognosis, and risk factors; and guidelines and reviews. References were captured if there was at least one term in each of the concepts. The search was limited to articles in the English language.

RESULTS

A total of 148 articles were identified via the literature search with further articles identified via review of references. Pediatric data regarding the etiology and development of CAV remain limited although knowledge about the immune and non-immune factors playing a role are increasing. CAV continues to be difficult to detect with many invasive and non-invasive methods available, yet their effectiveness in the detection of CAV remains suboptimal. There remains no proven medical intervention to treat or reverse established CAV disease, and CAV is associated with high rates of graft loss once detected. However, several medications are used in hopes of preventing, slowing progression, or modifying the outcomes.

CONCLUSION

This review provides a comprehensive overview of CAV, discusses its clinical presentation, risk factors, diagnostic tools used to identify CAV in the pediatric population, and highlights the current therapeutic options and the need for ongoing research.

Heart Transplant, Kawasaki Disease, and Bone Marrow Transplant: Are There Consequences?

PURPOSE OF REVIEW

This article reviews the current landscape of cardiovascular disease (CVD) risk factors, focusing on dyslipidemia, which contribute to atherosclerosis in three unique populations: youth less than 18 years-of-age with a history of Kawasaki disease, and those who have undergone orthotopic heart and bone marrow transplants.

RECENT FINDINGS

Atherosclerosis, the major cause of CVD, begins in childhood. Acquired and genetic disorders of lipid and lipoprotein metabolism, present at an early age, are major contributors to early precursors of atherosclerosis, which accelerate after age 20. Treatment of the underlying medical condition and optimum management of all risk factors is critical in improving outcomes. Nonetheless, limited data is available to assist clinical decision-making, with the aim of improving outcomes. Atherosclerosis, beginning in childhood, is multifactorial in origin with complex interplay of inflammation, infection, endothelial dysfunction, and dyslipidemia. Future studies are needed to help elucidate the specific roles of disease mechanisms, with an emphasis on early intervention and prediction of subclinical disease. In addition to a heart healthy lifestyle, there may be a role for use of lipid-lowering medications beginning at an early age.

Optical Coherence Tomography in Cardiac Allograft Vasculopathy: State-of-the-Art Review

Cardiac allograft vasculopathy (CAV) is a challenging complication of heart transplantation. CAV pathophysiology is incompletely understood, standard screening modalities such as angiography have significant limitations, and currently available therapies have only modest efficacy in preventing progression. Optical coherence tomography is a light-based technique that provides microscopic level catheter-based intravascular imaging and has dramatically expanded our understanding of CAV, demonstrating it to be a complex, heterogeneous, and dynamic process. This review covers characteristics and uses of optical coherence tomography, including vessel characterization, serial use to assess progression of disease, guiding percutaneous intervention, and monitoring response to CAV therapies. We also discuss the potential of optical coherence tomography in providing individualized assessment and enable customized CAV therapies, which may lead to improvements in long-term transplant outcomes.

Cardiac allograft vasculopathy: Differences of absolute and relative intimal hyperplasia in children versus adults in optical coherence tomography

BACKGROUND

Intracoronary imaging enables an early detection of intimal changes. To what extend the development of absolute and relative intimal hyperplasia in intracoronary imaging differs depending on age and post-transplant time is not known.

METHODS

Aim of our retrospective study was to compare findings between 24 pediatric (cohort P) and 21 adult HTx patients (cohort A) using optical coherence tomography (OCT) at corresponding post-transplant intervals (≤5 years: P1 (n = 11) and A1 (n = 10); >5 and ≤ 10 years: P2 (n = 13) and A2 (n = 11),. Coronary intima thickness (IT), media thickness (MT) and intima to media ratio (I/M) were assessed per quadrant. Maximal IT >0.3 mm was considered absolute, I/M > 1 relative intimal hyperplasia.

RESULTS

Compared to A1, I/M was significantly higher in P1 (maximal I/M: P1: 5.41 [2.81-13.39] vs. A1: 2.30 [1.55-3.62], p = 0.005), whereas absolute IT values were comparable. In contrast, I/M was comparable between P2 and A2, but absolute IT were significantly higher in A2 (maximal IT: P2: 0.16 mm [0.11-0.25] vs. A2: 0.40 mm [0.30-0.71], p < 0.001). A2 presented with higher absolute IT (maximal: A1: 0.16 mm [0.12-0.44] vs. A2: 0.40 mm [0.30-0.71], p = 0.02) and I/M (maximal I/M A1: 2.30 [1.55-3.62] vs. A2: 3.79 [3.01-5.62], p = 0.04).

CONCLUSION

Our results suggest an age- and time-dependent difference in the prevalence of absolute and relative intimal hyperplasia in OCT, with an early peak in children and a progressive increase in adults.

The Rationale, Indications, Safety, and Use of Statins in the Pediatric Population

Together with heart-healthy lifestyle habits, statins serve as the cornerstone of primary and secondary prevention of atherosclerotic cardiovascular disease in adults. Several conditions, most notably familial hypercholesterolemia (FH), cause early dyslipidemia and vascular disease, contributing to the development and progression of atherosclerosis from childhood and increased cardiovascular risk. In recent decades, studies increasingly have evaluated the safety and efficacy of statins in such high-risk youth. The strongest evidence for pediatric statin use is for the heterozygous FH population, whereby statin use has been shown to lower low-density lipoprotein cholesterol effectively, slow the progression of atherosclerosis and vascular dysfunction, and significantly reduce cardiovascular risk in early adulthood. Numerous meta-analyses and Cochrane reviews have demonstrated that attributed adverse effects, including liver toxicity, myositis, and rhabdomyolysis, occur no more frequently in youth receiving statins than placebos, with no impact on growth or development. However, further studies evaluating the long-term safety of pediatric statin use are required. In the current review, we summarize the pediatric experience of statin use to date, focusing on its utility for FH, Kawasaki disease, post-heart transplantation, and other at-risk populations. Current guidelines and indications for use are summarized, and the short- and medium-term safety experience is reviewed. Finally, a clinical approach to the indications, initiation, and monitoring of statins in youth is provided.

Early experience with pediatric cardiac transplantation in a limited resource setting

BACKGROUND

Pediatric heart transplantation is a now a well-established and standard treatment option for end stage heart failure for various conditions in children. Due to logistic issues, it is not an option for in most pediatric cardiac centres in the third world.

AIM

We sought to describe our early experience in the current era in India.

METHODS

This is a short term retrospective chart review of pediatric patients who underwent heart transplantation at our centre. Mean/Median with standard deviation /range was used to present data.

RESULTS

Twenty patients underwent orthotopic heart transplant between January 2016 and June 2019. The median age at transplant was 12.4years (range 3.3 to 17.3 years). The median weight was 23.2kg (range 10-80kg). The mean donor/recipient weight ratio was 1.62± 0.84. The mean ICU stay was 12.1days. The mean follow up post transplant was 2.03± 0.97years (range 10 days-3.57years). The 1 month and the 1 year survival was 100%. Biopsies were positive for significant rejection in 7 patients (35%). At the time of last follow-up, 3 patients (15%) had expired. The major post transplant morbidities were mechanical circulatory support (n=3), hypertension with seizure complex (n=3), post transplant lympho-proliferative disorder (n=1), pseudocyst of pancreas (n=1), coronary allograft vasculopathy (n=3) and systemic hypertension (n=7). All surviving patients (n=17) were asymptomatic at last follow up.

CONCLUSION

The results suggest acceptable short term outcomes in Indian pediatric patients can be achieved after heart transplantation in the current era. Significant rejection episodes and coronary allograft vasculopathy need careful follow up.

The pharmaceutical management of cardiac allograft vasculopathy after heart transplantation

INTRODUCTION

Cardiac allograft vasculopathy (CAV) is a major limitation to long-term survival after heart transplantation. Its peculiar pathophysiology involves multifactorial pathways including immune-mediated and metabolic risk factors, which are associated with the development of specific pathological lesions. The often diffuse and chronic nature of the disease reduces the effectiveness of revascularization procedures, and pharmacological prevention of the disease is the sole therapeutic approach with some proven efficacy.

AREAS COVERED

In this article, after briefly outlining the risk factors for CAV, the authors revise the potential pharmacological approaches that may reduce the burden of CAV. While several therapies have shown convincing efficacy in terms of CAV prevention diagnosed by coronary imaging, very few have been reported to improve prognosis with any meaningful level of evidence.

EXPERT OPINION

The authors believe that a customizable approach is necessary for clinical practice given the currently available evidence. Furthermore, it is important, in the future, to address the glaring therapeutic gap of an effective treatment against donor-specific antibodies, whose effect on endothelial injury is currently one of the major mechanisms of CAV development and for which no pharmacological treatment is currently available.

Cardiovascular Risk Reduction in High-Risk Pediatric Patients: A Scientific Statement From the American Heart Association

This scientific statement presents considerations for clinical management regarding the assessment and risk reduction of select pediatric populations at high risk for premature cardiovascular disease, including acquired arteriosclerosis or atherosclerosis. For each topic, the evidence for accelerated acquired coronary artery disease and stroke in childhood and adolescence and the evidence for benefit of interventions in youth will be reviewed. Children and adolescents may be at higher risk for cardiovascular disease because of significant atherosclerotic or arteriosclerotic risk factors, high-risk conditions that promote atherosclerosis, or coronary artery or other cardiac or vascular abnormalities that make the individual more vulnerable to the adverse effects of traditional cardiovascular risk factors. Existing scientific statements and guidelines will be referenced when applicable, and suggestions for risk identification and reduction specific to each setting will be described. This statement is directed toward pediatric cardiologists, primary care providers, and subspecialists who provide clinical care for these young patients. The focus will be on management and justification for management, minimizing information on pathophysiology and epidemiology.

Pediatric heart transplantation in the current era

PURPOSE OF REVIEW

To provide an international perspective and current review of pediatric heart transplantation (PHTx).

RECENT FINDINGS

Waitlist survival and long-term outcomes in PHTx continue to improve. Strategies to maximize donor pool utilization include ABO incompatible listing for infants and expanded donor-to-recipient weight ranges. However, there is a high degree of practice variation internationally, from listing strategies and donor acceptance practices to chronic immunosuppression regimens, long-term graft surveillance, and consideration for retransplantation.

SUMMARY

Common indications for PHTx include end-stage congenital heart disease and cardiomyopathy. Current median graft survival among PHTx recipients ranges from 13 to 22 years. Common morbidities include infection, rejection, renal dysfunction, coronary allograft vasculopathy, and posttransplant lymphoproliferative disease. International registry data, collaborative initiatives to standardize management, and multicenter studies continue to improve knowledge and advancement of the field.

Pediatric heart transplantation: long-term outcomes

Pediatric heart transplant has become the standard of care for end-stage heart disease in children throughout the world. The number of transplants has grown dramatically since the first transplant was performed, and over the last two decades, outcomes have consistently improved with progression in knowledge enhancing the clinical course and outcomes of these patients. Short-term outcomes in the most recent era have been excellent resulting in a renewed focus towards medium- and long-term outcomes. This article will review the most up-to-date literature on overall heart transplantation outcomes and specific long-term outcomes including rejection, cardiac allograft vasculopathy, graft failure, infection, renal dysfunction, malignancy, and the need for re-transplantation. The article also explores the post-transplantation outcomes of special populations, including Fontan patients, ABO-incompatible recipients, sensitized recipients, extracorporeal membrane oxygenation, and ventricular assist devices. The article concludes with a look at transition from pediatric to adult care and medication adherence, which are becoming major issues related to long-term outcomes as post-transplant survival increases.

Five decades of pediatric heart transplantation: challenges overcome, challenges remaining

PURPOSE OF REVIEW

Pediatric heart transplants continue to be the therapy of choice for children with end stage heart failure. The interplay of limited donor supply, improvement in ventricular assist device (VAD) technology and utilization, and a focus on optimizing long-term outcomes make it critically important for practitioners to be aware of an evolving diagnostic and therapeutic arsenal.

RECENT FINDINGS

Data suitable to define best practices for pediatric heart transplantation consist of an amalgam of small single center series, registry reviews and judicious inference from adult studies. Large-scale prospective pediatric studies are essentially nonexistent; the pediatric heart transplant study group continues to be highly productive while new collaboratives are emerging.

SUMMARY

Outcomes for pediatric transplants continue to improve. Technology and innovation continue to drive shifts in management. Improvements in VAD support along with refinement of solid-phase assays require clinicians to develop a deeper understanding of pre and post transplant management of donor-specific antibodies and antibody-mediated rejection. Expertise in retransplantation and the care of adults with congenital heart disease will be critical in the future.

Current state of pediatric cardiac transplantation

Pediatric heart transplantation is standard of care for children with end-stage heart failure. The diverse age range, diagnoses, and practice variations continue to challenge the development of evidence-based practices and new technologies. Outcomes in the most recent era are excellent, especially with the more widespread use of ventricular assist devices (VADs). Waitlist mortality remains high and knowledge of risk factors for death while waiting and following transplantation contributes to decision-making around transplant candidacy and timing of listing. The biggest gap impacting both waitlist and overall survival remains mechanical support options for infants and patients with single ventricle physiology. Though acute rejection has decreased progressively, both diagnosis and management of antibody-mediated rejection has become increasingly challenging and complex, as has the ability to understand the implication of anti-HLA antibodies detected both pre- and post-transplantation-including when and how to intervene. Trends in immunosuppression protocols include more use of induction therapy and steroid avoidance or withdrawal protocols. Common long-term morbidities include renal insufficiency, which can be mitigated with surveillance and renal-sparing strategies, and infections. Functional outcomes are excellent, but significant psychosocial challenges exist in relation to neurodevelopment, non-adherence, and transition from child-centered to adult-centered care. Cardiac allograft vasculopathy (CAV) remains a barrier to long-term survival, though it is more apparent that objective evidence of an impact on the allograft is important with regards to impact on outcomes. Retransplantation is rare in pediatric heart transplant recipients. Pediatric heart transplantation continues to evolve in order to address the challenges of the diverse group of patients that reach end-stage heart failure during childhood.

Vascular endothelial growth factor A is associated with the subsequent development of moderate or severe cardiac allograft vasculopathy in pediatric heart transplant recipients

BACKGROUND

Cardiac allograft vasculopathy (CAV) is the leading cause of chronic allograft loss after pediatric heart transplantation. We hypothesized that biomarkers of endothelial injury and repair would predict CAV development in pediatric heart transplant recipients.

METHODS

Blood was collected from pediatric heart transplant recipients at the time of routine annual coronary angiography, and the concentrations of 13 angiogenesis-related molecules were determined. The primary end point was the presence of moderate or severe CAV by angiography during a 5-year follow-up period.

RESULTS

The study enrolled 48 recipients (57% male) with a median age of 15.5 years (range, 2-22 years) and median time post-transplant of 5.8 years (range, 2-15 years). Eight recipients developed moderate/severe CAV at a median follow-up of 4.7 years, of whom 3 died, 3 underwent retransplantation, 1 had a myocardial infarction, and 1 was listed for retransplantation. Clinical characteristics associated with the development of moderate/severe CAV included prednisone use at enrollment (p = 0.03) and positive recipient cytomegalovirus immunoglobulin G at the time of transplant (p = < 0.01). Multivariable Cox proportional hazards regression identified plasma vascular endothelial growth factor (VEGF)-A concentration greater than 90 pg/ml at the time of blood draw as a significant predictor of time to moderate or severe CAV (hazard ratio, 14.3; 95% confidence interval, 1.3-163). Receiver operating characteristic curve analysis demonstrated that VEGF-A shows moderate performance for association with the subsequent development of CAV (area under the curve, 0.77; 95% confidence interval, 0.61-0.92).

CONCLUSIONS

VEGF-A levels in pediatric heart transplant recipients are associated with clinically important CAV progression within the subsequent 5 years.