The history of pediatric heart and lung transplantation

Pediatric Lung Transplantations: New Possibilities and Challenges in Treatment of Children With End-Stage Respiratory Failure

INTRODUCTION

Lung transplantation (LTx) is the last treatment option for children with end-stage respiratory failure. According to the literature, cystic fibrosis remains the most common cause of pediatric LTx. The study aimed to assess the characteristics of pediatric LTx recipients as well as the outcomes of the transplantation.

METHODS

Our study is a single-center retrospective review of clinical data of all 11 patients who underwent a LTx before the age of 18 years between the years 2016 and 2020. Medical records were examined for patients' characteristics, general treatment, and complications.

RESULTS

There were a total of 11 patients (8 males) with a median age 14.5 years (range: 11-17). The primary diseases that led to LTx were: cystic fibrosis in 8 patients (72.73%), hereditary hemorrhagic telangiectasia in 2 patients (18.18%), and idiopathic pulmonary arterial hypertension in 1 patient (9.09%). Median period from qualification to LTx was 235.55 days (range: 11-748). Two patients (18.18%) underwent lung retransplantation after 3 and 5 years. One patient passed away 10 months after surgery due to noncompliance.

CONCLUSIONS

Pediatric lung transplantation is less common than lung transplantation in adults. It also differs in fields of donors accessibility, stronger immune system response and noncompliance that may lead to graft failure.

Mitochondrial transplantation preserves myocardial function and viability in pediatric and neonatal pig hearts donated after circulatory death

OBJECTIVE

Mitochondrial transplantation has been shown to preserve myocardial function and viability in adult porcine hearts donated after circulatory death (DCD) . Herein, we investigate the efficacy of mitochondrial transplantation for the preservation of myocardial function and viability in neonatal and pediatric porcine DCD heart donation.

METHODS

Circulatory death was induced in neonatal and pediatric Yorkshire pigs by cessation of mechanical ventilation. Hearts underwent 20 or 36 minutes of warm ischemia time (WIT), 10 minutes of cold cardioplegic arrest, and then were harvested for ex situ heart perfusion (ESHP). Following 15 minutes of ESHP, hearts received either vehicle (VEH) or vehicle containing isolated autologous mitochondria (MITO). A sham nonischemic group (SHAM) did not undergo WIT, mimicking donation after brain death heart procurement. Hearts underwent 2 hours each of unloaded and loaded ESHP perfusion.

RESULTS

Following 4 hours of ESHP perfusion, left ventricle developed pressure, dP/dt max, and fractional shortening were significantly decreased (P < .001) in DCD hearts receiving VEH compared with SHAM hearts. In contrast, DCD hearts receiving MITO exhibited significantly preserved left ventricle developed pressure, dP/dt max, and fractional shortening (P < .001 each vs VEH, not significant vs SHAM). Infarct size was significantly decreased in DCD hearts receiving MITO as compared with VEH (P < .001). Pediatric DCD hearts subjected to extended WIT demonstrated significantly preserved fractional shortening and significantly decreased infarct size with MITO (P < .01 each vs VEH).

CONCLUSIONS

Mitochondrial transplantation in neonatal and pediatric pig DCD heart donation significantly enhances the preservation of myocardial function and viability and mitigates against damage secondary to extended WIT.

Lung transplantation in children

Lung transplantation is a well-established treatment for children facing advanced lung disease and pulmonary vascular disorders. However, organ shortage remains highest in children. For fitting the small chest of children, transplantation of downsized adult lungs, lobes, or even segments were successfully established. The worldwide median survival after pediatric lung transplantation is currently 5.7 years, while under consideration of age, underlying disease, and peri- and posttransplant center experience, median survival of more than 10 years is reported. Timing of referral for transplantation, ischemia-reperfusion injury, primary graft dysfunction, and acute and chronic rejection after transplantation remain the main challenges.

Disparities in lung transplantation in children

Lung transplantation is a recognized therapy for end-stage respiratory failure in children and young people. It is only available in selected countries and is limited by access to suitable organs. Data on disparities in access and outcomes for children undergoing lung transplantation are limited. It is clear from data from studies in adults, and from studies in other solid organ transplants in children, that systemic inequities exist in this field. While data relating specifically to pediatric lung transplantation are relatively sparse, professionals should be aware of the risk that healthcare systems may result in disparities in access and outcomes following lung transplantation in children.

A multicentric evaluation of pediatric lung transplantation in Italy

BACKGROUND

Pediatric lung transplantation is performed in highly experienced centers due to the peculiar population characteristics. The literature is limited and not representative of individual countries' differences. The purpose of this study was to analyze the Italian experience.

METHODS

A multicentric retrospective analysis was performed on 110 pediatric patients (<18 years old) who underwent lung transplantation from 1992 to 2019 at 9 Italian centers. Heart-lung transplantations and lung retransplantations were excluded.

RESULTS

The population was composed of 44 male and 66 female patients, with a median age of 15 years. The most frequent indication was cystic fibrosis (83%). One quarter of patients were transplanted in an emergency setting. Median donors' Oto score and age were 1 and 15 years, respectively, with 43% of adult donors. In 17% of patients a graft reduction was performed. Postoperatively, the median duration of mechanical ventilation, intensive care unit, and in-hospital stay were 48 hours, 11 and 35 days, respectively. Thirty-day mortality was 6%, and 1-, 5-, and 10-year survival was 72%, 52%, and 33%, respectively. Risk factors for mortality were Oto score and recipients' body mass index.

CONCLUSIONS

The outcomes of pediatric lung transplantation in Italy are comparable with current literature. Particular attention should be paid to the Oto score and recipient body mass index. Conversely, adult donors and graft reductions can be safely used to expand the donor pool.

Paediatric lung transplantation: the impact of age on the survival

OBJECTIVES

We herein review the outcomes of paediatric lung transplantation (LTx) and analyse subgroups divided by age.

METHODS

We retrospectively reviewed 43 consecutive paediatric LTx recipients (< 18 years old: cadaveric LTx [n = 9], living-donor lobar LTx [n = 34]). We also analysed subgroups of patients 1-6 years old (n = 10) and 7-17 years old (n = 33).

RESULTS

The 1-, 5- and 10-year overall survival (OS) rates in paediatric recipients were 93%, 82% and 67%, respectively. The 1-, 5- and 10-year graft dysfunction (GD)-free survival rates in paediatric recipients were 85%, 59% and 31%, respectively. The 1- and 5-year OS in the 1- to 6-year-old vs. 7- to 17-year-old groups were 70% vs. 100% and 48% vs. 93%, respectively (p < 0.0001). The 1- and 5-year GD-free survival rates in the 1- to 6-year-old vs. 7- to 17-year-old groups were 60% vs. 93% and 24% vs. 69%, respectively (p = 0.024). The 1- to 6-year-old group showed higher rates of non-standard LTx (p = 0.0001), interstitial pneumonia (p = 0.004) and ventilator dependency (p = 0.007) than the 7- to 17-year-old group.

CONCLUSION

Paediatric recipients under 7 years old seemed to have a higher risk of mortality and GD than those 7 years old and older.

The changing landscape of pediatric lung transplantation

There has been a shift over decades in the diagnostic indications for lung transplantation in children; in particular, there has been a reduction in the proportion of pediatric cystic fibrosis (CF) patients undergoing lung transplantation early in life, and more transplants occurring in other diagnostic groups. Here, we examine trends in pediatric lung transplantation with regards to indication by analyzing data from the United Network of Organ Sharing, the International Society for Heart and Lung Transplantation Thoracic Transplant Registry, and other sources. Over the past two years, there has been a precipitous decline in both the number of transplants due to CF and the proportion of CF cases relative to the total number of transplants, likely not solely due to the COVID-19 pandemic. In 2020, primary pulmonary arterial hypertension for the first time surpassed CF as main indication for pediatric lung transplantation in the United States, a finding that is also reflected in international data. We discuss the effect of novel CFTR modulator therapies as a major factor leading to this shifting landscape. Based on our trending, pulmonary hypertension-related diagnoses and pediatric interstitial lung diseases are rising indications, for which we suggest adjustments of consensus guidelines around candidate selection criteria. This article is protected by copyright. All rights reserved.

Trends in Survival for Pediatric Transplantation

OBJECTIVES

Progress in pediatric transplantation measured in the context of waitlist and posttransplant survival is well documented but falls short of providing a complete perspective for children and their families. An intent-to-treat analysis, in which we measure survival from listing to death regardless of whether a transplant is received, provides a more comprehensive perspective through which progress can be examined.

METHODS

Univariable and multivariable Cox regression was used to analyze factors impacting intent-to-treat survival in 12 984 children listed for heart transplant, 17 519 children listed for liver transplant, and 16 699 children listed for kidney transplant. The Kaplan-Meier method and log-rank test were used to assess change in waitlist, posttransplant, and intent-to-treat survival. Wait times and transplant rates were compared by using χ2 tests.

RESULTS

Intent-to-treat survival steadily improved from 1987 to 2017 in children listed for heart (hazard ratio [HR] 0.96, 95% confidence interval [CI] 0.96-0.97), liver (HR 0.95, 95% CI 0.94-0.97), and kidney (HR 0.97, 95% CI 0.95-0.99) transplant. Waitlist and posttransplant survival also improved steadily for all 3 organs. For heart transplant, the percentage of patients transplanted within 1 year significantly increased from 1987 to 2017 (60.8% vs 68.7%); however, no significant increase was observed in liver (68.9% vs 72.5%) or kidney (59.2% vs 62.7%) transplant.

CONCLUSIONS

Intent-to-treat survival, which is more representative of the patient perspective than individual metrics alone, steadily improved for heart, liver, and kidney transplant over the study period. Further efforts to maximize the donor pool, improve posttransplant outcomes, and optimize patient care while on the waitlist may contribute to future progress.

Lung and heart-lung transplantation for children with PAH: Dramatic benefits from the implementation of a high-priority allocation program in France

PURPOSE

Pulmonary arterial hypertension (PAH) is rare but remains fatal in infants and children despite the advance of targeted therapies. Lung transplantation (LTx), first performed in pediatric patients in the 1980s, is, with the Potts shunt, the only potentially life-extending option in patients with end-stage PAH but is possible only in tightly selected patients. Size-matching challenges severely restrict the donor organ pool, resulting-together with peculiarities of PAH in infants-in high waitlist mortality. We aimed to investigate survival when using a high-priority allocation program (HPAP) in children with PAH listed for double-LTx or heart-LTx.

METHODS

We conducted a single-center, retrospective, before-after study of consecutive children with severe Group 1 PAH listed for double-LTx or heart-LTx between 1988 and 2019. The HPAP was implemented in France in 2006 and 2007 for heart-LTx and double-LTx, respectively.

RESULTS

Fifty-five children with PAH were listed for transplantation. Mean age at transplantation was 15.8±2.8 years and 72% had heart-lung transplantation. PAH was usually idiopathic (65%) or due to congenital heart disease (25%). HPAP implementation resulted in the following significant benefits: Decreased cumulative incidence of waitlist death within 1 and 2 years (p < 0.0001); increased cumulative incidence of transplantation within 6 months, from 44% to 67% (p < 0.01); and improved survival after listing (at 1, 3, and 5 years: 61%, 50%, and 44% vs. 92%, 84%, and 72% before and after HPAP implementation, respectively; p = 0.02).

CONCLUSION

HPAP implementation was associated with significant improvements in access to transplantation and in survival after listing in children with end-stage PAH.

Lung transplantation as an intervention for pediatric pulmonary hypertension

Lung transplantation is a treatment option for selected children with end-stage lung disease and pulmonary vascular disorders. Overall, pulmonary hypertension (PH) is the second most frequent indication for infants and children requiring lung transplants. In pediatric PH patients, timing for listing remains a difficult decision due to patient heterogeneity and varying allocation policies across different countries. Furthermore, perioperative management can be challenging, making interdisciplinary collaboration among surgical, anesthesiology, critical care, and lung transplant teams essential. Because pediatric PH patients typically have preserved cardiac index and exercise tolerance even with advanced disease, they should be referred early even if they do not meet the criteria for listing of primarily adults by International Society for Heart and Lung Transplantation (ISHLT) published in 2015: New York Heart Association (NYHA) functional class III or IV without improvement, cardiac index < 2 L/min/m² , mean right atrial pressure of >15 mmHg. Bridging strategies with extracorporeal support should be determined at the time of listing in anticipation of possible clinical deterioration. Bilateral lung transplantation using cardiopulmonary bypass to provide hemodynamic stability is nowadays the standard surgical approach in pediatric centers. The immediate post-transplant period is characterized by dramatic changes in the right ventricle (RV) and and left ventricle (LV) anatomy and physiology, which can be life-threatening. Induction, immunosuppression, prophylaxis, and surveillance are not different from patients without PH. Overall, outcomes in pediatric lung and heart-lung transplant patients for PH are not different from those children undergoing transplantation for other indications. In fact, long-term survival is superior in children with idiopathic PH compared to other diseases, providing most recipients with improved quality of life.

Size Mismatching Increases Mortality After Lung Transplantation in Preadolescent Patients

BACKGROUND

The effect of size mismatch between donor and recipient in pediatric lung transplantation (PLTx) is currently unknown. Previous studies in adults have suggested that oversized allografts are associated with improved outcomes after lung transplantation. We investigated this relationship to quantify its effect on posttransplant outcomes in children.

METHODS

The United Network of Organ Sharing database was queried for preadolescent (age <13 years) patients undergoing PLTx. Donor-to-recipient height, weight, and predictive total lung capacity (pTLC; ages 4 to 13; pTLC = 0.160 x exp[0.021 x height]) ratios were calculated. Exploratory analysis was performed to identify disjoint intervals at which survival was statistically different. Patients were categorized as well-matched, undersized, or oversized. Multivariate Cox proportional hazard regression modeling assessed the adjusted effect of mismatching on mortality. Survival analysis was performed using the Kaplan-Meier method.

RESULTS

The analysis included 540 children. One-year mortality was higher with a height mismatch of 5% or less (hazard ratio [HR], 2.97; p = 0.001) and above 5% (HR, 2.22; p = 0.009). Similarly, 1-year mortality was worse with weight mismatch of 10% or less (HR, 1.99; p = 0.035) and above 10% (HR, 2.04; p = 0.028). On unadjusted analysis, a pTLC ratio of less than 0.9 was associated with worse survival (p = 0.017). This finding persisted after multivariate risk adjustment (HR, 2.93; p = 0.02). Contrary to findings in adults, an oversized allograft (pTLC ratio > 1.1) was not associated with improved survival (HR, 1.95; p = 0.147).

CONCLUSIONS

In preadolescent children undergoing PLTx, size mismatching is associated with increased death. Our findings differ from studies in adults, which demonstrated improved survival associated with oversized allografts. Accordingly, well-matched allografts should be prioritized when assessing donor-recipient pairs for transplantation.

Historical perspectives of lung transplantation: connecting the dots

Lung transplantation is now a treatment option for many patients with end-stage lung disease. Now 55 years since the first human lung transplant, this is a good time to reflect upon the history of lung transplantation, to recognize major milestones in the field, and to learn from others' unsuccessful transplant experiences. James Hardy was instrumental in developing experimental thoracic transplantation, performing the first human lung transplant in 1963. George Magovern and Adolph Yates carried out the second human lung transplant a few days later. With a combined survival of only 26 days for these first 2 lung transplant recipients, the specialty of lung transplantation clearly had a long way to go. The first "successful" lung transplant, in which the recipient survived for 10.5 months, was reported by Fritz Derom in 1971. Ten years later, Bruce Reitz and colleagues performed the first successful en bloc transplantation of the heart and one lung with a single distal tracheal anastomosis. In 1988, Alexander Patterson performed the first successful double lung transplant. The modern technique of sequential double lung transplantation and anastomosis performed at the mainstem bronchus level was originally described by Henri Metras in 1950, but was not reintroduced into the field until Pasque reported it again in 1990. Since then, lung transplantation has seen landmark changes: evolving immunosuppression regimens, clarifying the definition of primary graft dysfunction (PGD), establishing the lung allocation score (LAS), introducing extracorporeal membrane oxygenation (ECMO) as a bridge to transplant, allowing donation after cardiac death, and implementing ex vivo perfusion, to name a few. This article attempts to connect the historical dots in this field of research, with the hope that our effort helps summarize what has been achieved, and identifies opportunities for future generations of transplant pulmonologists and surgeons alike.

First pediatric bilateral lobar lung transplantation for cystic fibrosis in Russian Federation

Lung transplantation is not a routine treatment option of the pediatric lung diseases. Nowadays, there are performed not more than 100 of these operations per year worldwide due to the obvious diffi culty of obtaining the pediatric donor organs. One of the ways to solve this problem is using the adult donor lungs which have been previously reduced or anatomically partitioned. This is not a standard method of pediatric lung transplantation, but in case of the donor organs defi ciency it takes its place in the world medical practice. In this case we report the fi rst successful pediatric lung transplantation from adult donor in Russian Federation.

Pediatric lung transplantation

Pediatric lung transplantation has been undertaken since the 1980s, and it is today considered an accepted therapy option in carefully selected children with end-stage pulmonary diseases, providing carefully selected children a net survival benefit and improved health-related quality of life. Nowadays, >100 pediatric lung transplants are done worldwide every year. Here, specific pediatric aspects of lung transplantation are reviewed such as the surgical challenge, effects of immunosuppression on the developing pediatric immune system, and typical infections of childhood, as it is vital to comprehend that children undergoing lung transplants present a real challenge as children are not 'just small adults'. Further, an update on the management of the pediatric lung transplant patient is provided in this review, and future challenges outlined. Indications for lung transplantation in children are different compared to adults, the most common being cystic fibrosis (CF). However, the primary diagnoses leading to pediatric lung transplantation vary considerably by age group. Furthermore, there are regional differences regarding the primary indication for lung transplantation in children. Overall, early referral, careful patient selection and appropriate timing of listing are crucial to achieve real survival benefit. Although allograft function is to be preserved, immunosuppressant-related side effects are common in children post-transplantation. Strategies need to be put into practice to reduce drug-related side effects through careful therapeutic drug monitoring and lowering of target levels of immunosuppression, to avoid acute-reversible and chronic-irreversible renal damage. Instead of a "one fits all approach", tailored immunosuppression and a personalized therapy is to be advocated, particularly in children. Further, infectious complications are a common in children of all ages, accounting for almost 50% of death in the first year post-transplantation. However, chronic lung allograft dysfunction (CLAD) remains the major obstacle for improved long-term survival.

Pediatric lung transplantation

Pediatric lung transplantation is a highly specialized clinical endeavor. Since the late 1980's, there have only been slightly more than 2200 implants reported to the International Society for Heart and Lung transplantation registry. This review will discuss the historical aspects of pediatric lung transplantation. It will familiarize the reader with the current indications for transplant and the referral and listing process. The current state of lung assist devices as a bridge to pediatric lung transplantation is discussed in addition to the technical aspects of the transplant procedure. Finally, posttransplant outcomes, including anticipated morbidity and the role of retransplantation, are clarified.

Neuropsychological functioning in preschool-aged children undergoing evaluation for organ transplant

OBJECTIVE

The purpose of this study was to review the current literature on neuropsychological functioning in two groups of children requiring organ transplants (liver or heart) and present recent clinical data collected through the liver and cardiac transplantation programs at a large pediatric academic medical center.

METHOD

Data included in this study came from 18 patients who completed evaluations for heart transplant (n = 8) or liver transplant (n = 10) between the ages of 2 and 6 years (inclusive). Measures examining neurocognitive, emotional-behavioral, and adaptive functioning were collected as part of standard pre-transplant clinical neuropsychological evaluations. Within each organ group, mean scores were calculated and compared with normative population mean scores using one sample t-tests. In addition, non-parametric binomial tests were calculated to examine whether the proportion of individuals falling more than one standard deviation below the population mean was significantly greater in the patient groups than the normative population base rate of 16%.

RESULTS

Patients in both groups performed below normative expectation in several neurocognitive and adaptive domains. However, neither group showed significant difficulties in behavioral or emotional regulation.

CONCLUSIONS

Results from this study document cognitive delays in preschool-aged children undergoing evaluations for liver transplant or heart transplant, highlighting the importance of intervention and long-term monitoring of these two patient populations, as well as the need for neuropsychologist involvement with transplant teams.

Special considerations for the use of lung transplantation in pediatrics

Lung transplantation has become an accepted therapy in infants, children and adolescents suffering from end-stage lung diseases, an impaired quality of life as well as a reduced life expectancy. Within Europe, pediatric lung transplantation is largely performed in predominantly adult centers due to a relatively low overall case volume. Children do represent a specific and challenging cohort facing a transplant procedure, where the selection of potential candidates becomes a crucial step to maximize net survival benefit. Therefore, interdisciplinary evaluation and early listing in view of current indications and contraindications, adequate preoperative education of the child and family members, discussion of possibly required bridging procedures in case of deterioration, appropriate technical planning of the operation, adherence to postoperative medical treatment and follow-up are all crucial steps in this demanding puzzle. In this article, the authors review recent advances in the field of pediatric lung transplantation and outline challenges in the future.

The evolving potential for pediatric ex vivo lung perfusion

Despite the rise in the number of adult lung transplantations performed, rates of pediatric lung transplantation remain low. Lung transplantation is an accepted therapy for pediatric end-stage lung disease; however, it is limited by a shortage of donor organs. EVLP has emerged as a platform for assessment and preservation of donor lung function. EVLP has been adopted in adult lung transplantation and has successfully led to increased adult lung transplantations and donor lung utilization. We discuss the future implications of EVLP utilization, specifically, its potential evolving role in overcoming donor shortages in smaller children and adolescents to improve the quality and outcomes of lung transplantation in pediatric patients.

Lung transplantation: overall approach regarding its major aspects

Lung transplantation is a well-established treatment for patients with advanced lung disease. The evaluation of a candidate for transplantation is a complex task and involves a multidisciplinary team that follows the patient beyond the postoperative period. Currently, the mean time on the waiting list for lung transplantation in the state of São Paulo, Brazil, is approximately 18 months. For Brazil as a whole, data from the Brazilian Organ Transplant Association show that, in 2014, there were 67 lung transplants and 204 patients on the waiting list for lung transplantation. Lung transplantation is most often indicated in cases of COPD, cystic fibrosis, interstitial lung disease, non-cystic fibrosis bronchiectasis, and pulmonary hypertension. This comprehensive review aimed to address the major aspects of lung transplantation: indications, contraindications, evaluation of transplant candidates, evaluation of donor candidates, management of transplant recipients, and major complications. To that end, we based our research on the International Society for Heart and Lung Transplantation guidelines and on the protocols used by our Lung Transplant Group in the city of São Paulo, Brazil.

Current State of Pediatric Lung Transplantation

Cardiothoracic transplantation has significantly impacted the lives of pediatric patients with advanced cardiopulmonary failure. The current state of lung transplantation in children as well as its ongoing and future challenges are discussed.

More lessons learned from the Pediatric Heart Transplant Study

Paediatric heart transplantation has evolved over the last 3 decades. The research group, Pediatric Heart Transplant Study, has been in step with that evolution over the nearly 20 years of its existence by utilising its registry to contribute a wealth of clinical research to the field. The highlights of its studies will be presented in this review.

Pediatric lung transplantation: indications and outcomes

Lung transplantation (LTx) is a treatment option for infants and children with untreatable and otherwise fatal pulmonary diseases. To date, over 1,800 lung transplants have been performed, most frequently in children over the age of five years. The most common indications for transplantation in children overall are cystic fibrosis (CF) and idiopathic pulmonary hypertension (PH). The surfactant protein deficiencies, other interstitial lung diseases (ILDs), and congenital heart disease are important indications among young children and infants. Re-transplantation is an option for selected recipients with chronic allograft rejection. Overall survival following pediatric LTx is similar to that encountered in adult patients, with recent registry data indicating a median survival of 4.9 years. Other outcomes such as the incidence of bronchiolitis obliterans (BO) and the presence of key post-transplant co-morbid conditions are also similar to the experience in adult lung transplant recipients.

Pediatric lung transplantation: promise being realized

PURPOSE OF REVIEW

Lung transplantation for infants and children is an accepted but rarely exercised option for the treatment of end-stage lung disease, with outcomes equivalent to those for adults. However, widespread misconceptions regarding pediatric outcomes often confound timely and appropriate referral to specialty centers. We present the updated information for primary pediatricians to utilize when counseling families with children confronted by progressive end-stage pulmonary or cardiovascular disease.

RECENT FINDINGS

We provide general guidelines to consider for referral, and discuss allocation of organs in children, information regarding standard treatment protocols, and survival outcomes.

SUMMARY

Lung transplantation is a worthwhile treatment option to consider in children with end-stage lung disease. The treatment is complex, but lung transplant provides substantial survival benefit and markedly improved quality of life for children and their families. This timely review provides comprehensive information for pediatricians who are considering options for treatment of children with end-stage lung disease.

Pediatric lung transplantation: 10 years of experience

Lung transplantation is a well-established treatment for advanced lung diseases. In children, the diseases that most commonly lead to the need for a transplantation are cystic fibrosis, pulmonary hypertension, and bronchiolitis. However, the number of pediatric lung transplantations being performed is low compared with the number of transplants performed in the adult age group. The objective of this study was to demonstrate our experience with pediatric lung transplants over a 10-year period in a program initially designed for adults.

Pediatric lung transplantation

Lung transplantation is an accepted therapy for selected pediatric patients with severe end-stage vascular or parenchymal lung disease. Collaboration between the patients' primary care physicians, the lung transplant team, patients, and patients' families is essential. The challenges of this treatment include the limited availability of suitable donor organs, the toxicity of immunosuppressive medications needed to prevent rejection, the prevention and treatment of obliterative bronchiolitis, and maximizing growth, development, and quality of life of the recipients. This article describes the current status of pediatric lung transplantation, indications for listing, evaluation of recipient and donor, updates on the operative procedure,graft dysfunction, and the risk factors, outcomes, and future directions.

Lung transplantation in infants and toddlers from 1990 to 2004 at St. Louis Children's Hospital

In a retrospective, single-center cohort study, outcomes of infants and toddlers undergoing lung transplant at St. Louis Children's Hospital between 1990 and 2004 were compared to older children. Patients with cystic fibrosis (exclusively older children) and those who underwent heart-lung, liver-lung, single lung or a second transplantation were excluded from comparisons. One hundred nine lung transplants were compared. Thirty-six were in infants <1 year old, 26 in toddlers 1-3 years old and 47 in children >3 years old. Graft survival was similar for infants and toddlers (p = 0.35 and p = 0.3, respectively) compared to children over 3 years old at 1 and 3 years after transplant. Significantly more infants (p < 0.0001 and p = 0.003) and toddlers (p = 0.002 and p = 0.03) were free from acute rejection and bronchiolitis obliterans compared to older patients. While most infants and toddlers had only minimal lung function impairment, and achieved normal to mildly delayed developmental scores, somatic growth remained depressed 5 years after transplant. Lung transplantation in infants and young children carries similar survival rates to older children and adults. Further insights into the unique immunologic aspects of this group of patients may elucidate strategies to prevent acute and chronic rejection in all age groups.

A national conference to determine research priorities in pediatric solid organ transplantation

The need for evidence-based practice guidelines requires high quality, carefully controlled clinical research trials. This multidisciplinary conference attempted to: identify urgent clinical and research issues, identify obstacles to performing clinical trials, develop concepts for organ-specific and all-organ research and generate a report that would serve as a blueprint for future research initiatives. A few themes became evident. First, young children present a unique immunologic environment which may lead to tolerance, therefore, including young children in immunosuppression withdrawal and tolerance trials may increase the potential benefits of these studies. Second, adolescence poses significant barriers to successful transplantation. Non-adherence may be insufficient to explain poorer outcomes. More studies focused on identification and prevention of non-adherence, and the potential effects of puberty are required. Third, the relatively naive immune system of the child presents a unique opportunity to study primary infections and alloimmune responses. Finally, relatively small numbers of transplants performed in pediatric centers mandate multicenter collaboration. Investment in registries, tissue and DNA repositories will enhance productivity. The past decade has proven that outcomes after pediatric transplantation can be comparable to adults. The pediatric community now has the opportunity to design and complete studies that enhance outcomes for all transplant recipients.

Pediatric lung transplantation: a therapy in its adolescence

Pediatric lung transplant was born at the University of Toronto as an extension of the pioneering work of Cooper and Patterson in adult lung transplant in the 1980s. Through the 1990s, the field of pediatric lung transplantation grew with clinical outcomes in the largest centers being comparable to those in adult lung transplantation. For children and adults, the largest obstacle to long-term survival remains chronic allograft rejection secondary to the development of bronchiolitis obliterans, for which little advancement has been made in prevention or treatment. While transplantation has become accepted therapy for end-stage lung disease in adults, pediatric lung transplant has been less widely embraced for multiple reasons, such as adolescent non-compliance and the investment required in developing freestanding pediatric lung transplant centers. Another factor limiting pediatric lung transplant has been the paucity of suitable donor lungs. In 2002, Texas Children's Hospital and the Baylor College of Medicine successfully collaborated in developing an active and successful pediatric lung transplant program. Through our own work and an international collaborative of pediatric transplant pulmonologists and surgeons, we are hoping to move the field of pediatric lung transplant out of its "adolescence" into adulthood.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Heart and lung transplantation in children

During the past two decades, several advances have resulted in marked improvement in medium-term survival for infants and children undergoing heart transplantation. Unfortunately, progress has been less dramatic in the field of lung and heart-lung transplantation, where there is little evidence of improved outcomes. The procedures remain palliative and all transplant recipients are at risk for the adverse effects of non-specific immunosuppression, including infections, lymphoproliferative disorders, and non-lymphoid malignancies. In addition, current immunosuppressive agents have narrow therapeutic windows and exhibit a wide array of organ toxicities, posing special challenges for the young patient who must endure life-long immunosuppression. New immunosuppressive regimens have lowered the rates of acute rejection but appear to have had relatively little impact on the incidence of chronic rejection, the principal cause of late graft loss. The ultimate goal is to induce a state of donor-specific tolerance, wherein the recipient will accept the allograft indefinitely without the need for long-term immunosuppression. This quest is currently being realised in animal models of solid organ transplantation, and offers great hope for children undergoing heart and lung transplantation in the future.

Anesthesia Considerations for Pediatric Thoracic Solid Organ Transplant

This article discusses the indications, perioperative management, postoperative complications, and patient outcome of pediatric heart transplantation and pediatric lung transplantation. Special emphasis is placed on the anesthetic considerations relevant for children who are undergoing or have received a solid thoracic organ transplant.

Pediatric lung transplantation: update 2003

In the past 15 years there have been more than 1200 pediatric lung and heart-lung transplants worldwide. This article regarding the current status of pediatric lung transplantation describes indications, outcomes, and complications, with particular emphasis on issues specific to pediatrics, including growth. Information useful to the pediatrician and pediatric pulmonologist is also included. Issues important to the future are reviewed.