Pediatric heart transplantation

Children with heart transplants: Lessons learned from 774 visits at a primary community clinic

Aims Unexpected decompensation of PHTRs may surprise, when the patient is at home. If the PHTR lives a distance from transplant center, the task of identifying risk factors of allograft rejection/dysfunction falls primarily on the PCP in the PCC, whether or not they are knowledgeable toward pediatric heart-transplantation. Methods We reviewed the medical reports of three heart-transplanted children in our periphery clinic between the years 2005 and 2019. Results The unexpected death of one patient, hours after he left our health facility, was the impetus for writing this article. Another heart transplant child attended our periphery clinic for 774 visits. Majority of visits were casual, others were scheduled, and the rest were for administrative affairs. We referred the PHTR to the transplantation center in 9% of all visits. In remaining 91% visits, we handled problems locally. Conclusions One of the important lessons we have learned through handling the PHTR at the PCC is that, during daily workflows and dealing with the occasional visits of a heart transplant child, related critical clinical information to allograft rejection or its dysfunction can easily evade from awareness of the attending physician. Through this study, we demonstrated that a program of summoning the PHTR to "initiated monthly visits" at the PCC enables the PCP to be maximally aware of critical clinical information, in addition to limiting futile referrals of 91% of the visits to specialized centers, without adversely affecting the prognosis.

Peri-operative kidney injury and long-term chronic kidney disease following orthotopic heart transplantation in children

Significant advances in cardiac intensive care including extracorporeal life support have enabled children with complex congenital heart disease and end-stage heart failure to be supported while awaiting transplantation. With an increasing number of survivors after heart transplantation in children, the complications from long-term immunosuppression, including renal insufficiency, are becoming more apparent. Severe renal dysfunction after heart transplant is defined by a serum creatinine level >2.5 mg/dL (221 μmol/L), and/or need for dialysis or renal transplant. The degree of renal dysfunction is variable and is progressive over time. About 3-10 % of heart transplant recipients will go on to develop severe renal dysfunction within the first 10 years post-transplantation. Multiple risk factors for chronic kidney disease post-transplant have been identified, which include pre-transplant worsening renal function, recipient demographics and morbidity, peri-transplant haemodynamics and long-term exposure to calcineurin inhibitors. Renal insufficiency increases the risk of post-transplant morbidity and mortality. Hence, screening for renal dysfunction pre-, peri- and post-transplantation is important. Early and timely detection of renal insufficiency may help minimize renal insults, and allow prompt implementation of renoprotective strategies. Close monitoring and pre-emptive management of renal dysfunction is an integral aspect of peri-transplant and subsequent post-transplant long-term care.

The effect of gender and gender match on mortality in pediatric heart transplantation

The effect of organ-recipient gender match on pediatric heart transplant mortality is unknown. We analyzed the effects of gender and donor-recipient gender matching. Based on Organ Procurement and Transplant Network data, we performed a historical cohort study in a population of 3630 heart transplant recipients less than 18 years old. We compared unadjusted and adjusted mortality by recipient gender, donor gender and between gender-matched and gender-mismatched recipients. Female recipients had decreased survival compared to male recipients (unadjusted hazard ratio [HR] 1.16, confidence interval [CI] 1.02-1.31; p = 0.020). Organ-recipient gender mismatch did not affect mortality for either male or female recipients, though gender-mismatched females had the worst survival compared to gender-matched males, who had the best survival (unadjusted HR 1.26, CI 1.07-1.49; p = 0.005). After adjustment for other risk factors affecting transplant mortality, female recipients had decreased survival compared to male recipients (HR 1.27, CI 1.12-1.44; p = 0.020) and gender matching had no effect. In conclusion, gender mismatch alone did not increase long-term mortality for pediatric heart transplant recipients. However, there may be additive effects of gender and gender matching affecting survival. There are insufficient data at this time to support that recipient and donor gender should affect heart allocation in children.

Acute right ventricular failure after pediatric cardiac transplant: predictors and long-term outcome in current era of transplantation medicine

OBJECTIVES

To identify pretransplant factors associated with postprocedural right ventricular failure and the relationship between right ventricular failure and long-term survival in children.

METHODS

Records were reviewed for children having heart transplantation from 2000 to 2006.

RESULTS

Right ventricular failure was identified by clinical and echocardiographic parameters in 33/129 (25%) recipients: dilated cardiomyopathy in 14/90 (15%), congenital heart disease in 11/27 (41%), and restrictive cardiomyopathy in 8/12 (66%). In 9 of 12 (75%), known elevated (reactive) pulmonary vascular resistance progressed to right ventricular failure. In a further 23/117 (20%) recipients, pulmonary vascular resistance within predefined acceptable range progressed to right ventricular failure. Multiple logistic regression analyses indicated elevated pulmonary vascular resistance (odds ratio 12.30; 95% confidence interval 2.73, 55.32; P = .001) and primary diagnosis, restrictive cardiomyopathy (odds ratio 9.21; 95% confidence interval 2.07, 41.12; P = .004), and congenital heart disease (odds ratio 4.07; 95% confidence interval 1.36, 12.19; P = .012) were strongly associated with right ventricular failure, but duration of heart failure, pretransplant mechanical support, donor status, and ischemic times were not. Treatment included inhaled nitric oxide in 28 (84%), mechanical support in 10 (31%), hemofiltration in 13 (40%), and retransplantation in 2. A Cox multiple regression model including: primary diagnosis, right ventricular failure, and elevated pulmonary vascular resistance indicated that only the latter was independently linked with eventual mortality (hazards ratio 5.45; 95% confidence interval 1.36, 21.96; P = .017).

CONCLUSIONS

Primary diagnosis and pretransplant elevated reactive pulmonary vascular resistance are both linked to the evolution of right ventricular failure. Pulmonary vascular resistance assessment in end-stage heart failure is challenging; therefore, avoidance of right ventricular failure may not always be possible. Aggressive early treatment may mitigate the effects of right ventricular failure: pretransplant elevated pulmonary vascular resistance was independently associated with long-term survival, but right ventricular failure was not.

Outcome of extracorporeal membrane oxygenation for early primary graft failure after pediatric heart transplantation

OBJECTIVES

We sought to analyze the indications and outcome of extracorporeal membrane oxygenation (ECMO) for early primary graft failure and determine its impact on long-term graft function and rejection risk.

BACKGROUND

Early post-operative graft failure requiring ECMO can complicate heart transplantation.

METHODS

A retrospective review of all children requiring ECMO in the early period after transplantation from 1990 to 2007 was undertaken.

RESULTS

Twenty-eight (9%) of 310 children who underwent transplantation for cardiomyopathy (n = 5) or congenital heart disease (n = 23) required ECMO support. The total ischemic time was significantly longer for ECMO-rescued recipients compared with our overall transplantation population (276 +/- 86 min vs. 242 +/- 70 min, p < 0.01). The indication for transplantation, for ECMO support, and the timing of cannulation had no impact on survival. Hyperacute rejection was uncommon. Fifteen children were successfully weaned off ECMO and discharged alive (54%). Mean duration of ECMO was 2.8 days for survivors (median 3 days) compared with 4.8 days for nonsurvivors (median 5 days). There was 100% 3-year survival in the ECMO survivor group, with 13 patients (46%) currently alive at a mean follow-up of 8.1 +/- 3.8 years. The graft function was preserved (shortening fraction 36 +/- 7%), despite an increased number of early rejection episodes (1.7 +/- 1.6 vs. 0.7 +/- 1.3, overall transplant population, p < 0.05) and hemodynamically comprising rejection episodes (1.3 +/- 1.9 vs. 0.7 +/- 1.3, overall transplant population, p < 0.05).

CONCLUSIONS

Overall survival was 54%, with all patients surviving to at least 3 years after undergoing transplantation. None of the children requiring >4 days of ECMO support survived. Despite an increased number of early and hemodynamically compromising rejections, the long-term graft function is similar to our overall transplantation population.

Children with chronic organ failure possibly ending in organ transplantation: a survey in an Italian region of 5,000,000 inhabitants

AIM

The Italian Piedmont region sponsored in 2005 a population-based registry to assess the epidemiology of childhood chronic organ failure involving kidneys, liver, heart or lungs.

METHODS

Patients in chronic organ failure who were younger than 18 years were selected, and entered the registry when accomplishing the standard failure criteria for each organ. The cases were reported by the general paediatricians of the region and integrated with the data gathered by the Children University Hospital, a tertiary care centre.

RESULTS

In Piedmont (647,727 inhabitants < 18 years), a total of 146 children (217 cases per million of paediatric population) were found to be affected by chronic organ failure (mean age 10 years; range 0-17). The organ failure involved kidneys in 68 subjects (48%), liver in 24 (17%), heart in 21 (15%) and lungs in 28 (20%), and was severe in 32 subjects (6 on transplantation waiting list). The most represented disease leading to chronic renal failure was renal hypodysplasia (79%). Chronic liver failure was mostly caused by biliary atresia (30%), autoimmune hepatitis (25%) and Wilson's disease (21%). Dilated cardiomyopathy (62%) and surgically treated congenital cardiopathy were the two leading causes of chronic heart failure. The most represented disease leading to chronic lung failure was cystic fibrosis (89%).

CONCLUSION

This is the first report of the literature focusing on the epidemiology of chronic organ failure in children encompassing a region of 4,000,000 inhabitants. This clinical condition is rare, but medically and socially very demanding not only in childhood but the life along, as most of these patients will need solid organ transplantation decades later.

Waiting before birth: outcomes after fetal listing for heart transplantation

Following fetal diagnosis of a profound heart defect, transplantation (HTx) is an alternative to pregnancy termination or neonatal surgical palliation. Retrospective review of the cardiac and transplant databases of fetal listings for HTx between 1990 and July 2006 was undertaken to describe outcomes after listing. We identified 26 fetal listings (of 269 total listings). Diagnoses included congenital heart disease (n = 24) and cardiomyopathy (n = 2). Seven patients were delisted after birth: in five cases parents opted for surgical palliation, two clinically improved. One patient died wait-listed (stillborn). Time wait-listed as a fetus ranged from 1-41 days (median 19 days). Eighteen patients underwent HTx (median weight 2.8 kg, range 2.1-10.9 kg); median days wait-listed after birth was 22 (4 h-123 days). Two fetuses were surgically delivered at 36 weeks gestation when a donor organ became available; 11 were transplanted as neonates (<30 days). The median age at HTx was 1 month (4 h-2.6 months). Fetal listing for HTx increases the potential window of opportunity for a donor organ to become available; patients had low wait-list mortality and a fair intermediate-term outcome. Well-defined criteria for eligibility for fetal listing and priority allocation to infants over fetuses seem rational approaches for centers that offer fetal listing.

Care of the acutely ill pediatric heart transplant recipient

Young children may present to the emergency department after undergoing orthotopic heart transplantation. Emergency department care of pediatric heart transplant recipients with an acute illness is not clearly defined. To assist the emergency physician with treating these children, 2 cases are detailed to demonstrate the variation in outcome of young children presenting to the emergency department with acute illness months after their transplant. The cases typify the varied outcomes possible after emergency department presentation. After the cases, a review of the medical conditions common in transplant recipients precedes a description of management suggestions.

Efficacy of signal-averaged electrocardiography in the young orthotopic heart transplant patient to detect allograft rejection

Endomyocardial biopsy is the gold standard survey for cardiac graft rejection. Signal-averaged electrocardiography (SAECG) identifies slowly conducting, diseased myocardium. We sought to determine whether SAECG is a sensitive, noninvasive transplant surveillance method in the young.Ninety-four SAECGs recorded prior to biopsy in 20 young transplant (OHT) patients and those from 15 healthy age-matched controls (CTL) were analyzed. In the OHT group, 56 no-rejection (NOREJ) (ISHLT grades 0 or 1 A) and 37 acute rejection (REJ) (ISHLT grades IB, 2, and 3A) SAECGs were compared, SAECGs were filtered at 40-255 Hz. Total QRS duration (QRSd), duration of terminal low amplitude of QRS under 40 microV (LAS), and root mean square amplitude of terminal 40 msec of QRS (RMS40) were compared.SAECGs were significantly different in CTL vs NOREJ but not in NOREJ vs REJ: QRSd, 81.7 +/- 8, 107.2 +/- 18.4, and 112.3 +/- 21.6 msec, respectively; LAS, (18 +/- 5.8, 23.6 +/- 10.7, and 27 +/- 14.8 msec, respectively; and RMS40, (169.3 +/- 100.4, 68 +/- 48.8, and 57.5 +/- 45.6 microV, respectively. Children following OHT exhibited significant differences in the SAECG compared to controls. Differences between the NOREJ and REJ groups were negligible. Therefore, SAECG may not be effective in detecting OHT rejection in the young.

Postmortem intracranial neuropathology in children following cardiac transplantation

At Loma Linda University Children's Hospital, the medical information of 405 pediatric patients who received orthotopic cardiac transplantation were reviewed. Of those who died (n=136), 86% (n=117) underwent postmortem examinations, and the brain was examined in 61% (n=82, male=39). The number and type of intracranial lesions present were compiled, and these were matched to underlying functional cardiac disease categories. Intracranial abnormalities were present in 87%. Infarct was the most common primary central nervous system pathology in hypoplastic left heart syndrome (41%) but was also observed frequently in children with obstructive lesions (37%), cyanotic disease (31%), or cardiac shunting (29%). Secondary findings included extraparenchymal hemorrhage in obstructive lesions (31%); hypoxic changes occurred in 15% of patients with cyanotic disease and in 14% of those with cardiac shunting. Thirty-three percent of children with restrictive lesions had no neuropathology reported. Postmortem examination brain weights were matched against age and sex norms, with 29% of females and 36% of males below two standard deviations. These findings revealed that intracranial pathology was present in the majority of transplanted children who underwent postmortem examination, and that infarctive changes constituted the most common neuropathologic abnormality. Additionally, a number of children had significantly reduced brain weight.

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.

Ten- and 20-year survivors of pediatric orthotopic heart transplantation

BACKGROUND

Pediatric heart transplantation is entering its third decade, allowing for the first time an analysis of a large group of true long-term survivors, specifically children who have survived > or =10 years post-transplantation.

METHODS

Fifty-two patients < or =18 years, who had undergone heart transplantation at Stanford between August 1974 and June 1993 and survived > or =10 years, were retrospectively reviewed.

RESULTS

Forty (77%) patients are currently alive. Thirteen survived >15 years and 5 >20 years (the longest being 26 years). Actuarial survival was 79.4% at 14 years and 53.1% at 20 years. Cardiomyopathy was the reason for transplantation in 71% and congenital heart disease (CHD) in 29%. At last evaluation, 71% were on a cyclosporine-based regimen and 23% a tacrolimus-based regimen; 33% were steroid-free. Twenty-seven percent were totally free from treatable rejection, 44% developed serious infections, 69% were receiving anti-hypertensives, and 8% required renal transplantation. Neoplasms occurred in 23%, graft coronary artery disease (CAD) in 31%, and 15% required re-transplantation. Of the 12 deaths, CAD was the most common cause (n = 4), followed by non-specific late graft failure (n = 3), infection (n = 2), rejection (n = 1), non-lymphoid cancer (n = 1) and lymphoid cancer (n = 1). Physical rehabilitation and return to normal lifestyle has been nearly 100%.

CONCLUSIONS

Heart transplantation in pediatric patients is compatible with true long-term survival with a growing cohort of children approaching their second and third decades. The gradual constant-phase decrease in survival noted in earlier studies appears to be continuing. Rejection and infection are low but persistent risks after the first years. Graft CAD and non-specific late graft dysfunction are the leading causes of death after 10 years. Rehabilitation is excellent.

Cardiovascular Emergencies in the Pediatric Patient

Children who have heart disease may present to the emergency department (ED) in many stages of life with a range of cardiovascular manifestions, from minimally irritating palpitations to the life-threatening derangements of shock or lethal dysrhythmia. They can present with congenital heart disease, after a temporizing procedure has been performed or after their definitive repair. Children can also present with fever, weakness, dyspnea, syncope, or chest pain; alternatively, children may present to the ED with active dysrhythmia, pulmonary edema, or cardiogenic shock . These symptoms and presentations may result from Kawasaki disease,hypertrophic cardiomyopathy, or arrhythmia; therefore, emergency physicians must also be comfortable with the most common types of heart disease associated with these symptoms and presentations. The purpose of this article is to describe the physiology and presentation of undiagnosed congenital heart disease, to describe the complications that can occur after a staged or definitive repair,and to discuss acquired heart disease in children.

Tolerance: is it achievable in pediatric solid organ transplantation?

Significant advances have been made in the understanding of allograft rejection. There is growing awareness that allograft acceptance, or tolerance, is also an active process rather than a passive absence of rejection. Mechanistic awareness of this process has spawned many preclinical strategies for the prevention of allograft rejection without the need for chronic immunosuppression. These therapies are currently entering clinical trials. This article reviews the prevailing therapies that hold promise for future clinical application. In particular, their application in children is discussed, as are biologic aspects of childhood immunity that may play a role in the success or failure of these strategies.

Immunosuppression in Pediatric Heart Transplantation: 2003 and Beyond

Advances in immunosuppressive therapy have contributed to the improved long-term survival of pediatric heart transplant recipients over the past two decades. The introduction of cyclosporine in the early 1980s (the first oral agent to selectively target T-lymphocyte pathways) led to a dramatic reduction in acute rejection rates and improved graft and patient survival. A combination of cyclosporine, azathioprine, and corticosteroids ("triple therapy") became the standard of care for pediatric and adult heart transplantation. The introduction of several new agents in the past decade has resulted in an almost infinite number of potential immunosuppressive regimens, none of which have been (or are likely to be) tested in randomized clinical trials in children. Tacrolimus is replacing cyclosporine as the primary calcineurin inhibitor in many programs. Mycophenolate mofetil, despite its increased cost, is likely to replace azathioprine as the adjunctive antimetabolite of choice in heart transplantation. Furthermore, target of rapamycin inhibitors, such as sirolimus, will likely be used in lieu of antimetabolite agents if their known myointimal antiproliferative effects are demonstrated to reduce or prevent graft vasculopathy (chronic rejection) in humans. With the availability of more potent immunosuppressive agents, early steroid withdrawal or complete steroid avoidance will become the standard of care in most pediatric transplant programs. Complete avoidance of steroids can be facilitated by the use of induction therapy with polyclonal anti-T-cell antibodies (eg, rabbit antithymocyte globulin ) or with the use of nondepleting antibodies that block the interleukin-2 receptor (eg, basiliximab, daclizumab). All these agents appear to have a good safety profile and are likely to lead to a resurgence of interest in induction therapy as a strategy to avoid chronic use of corticosteroids in children. As the elucidation of immunosuppressive pathways continues to advance, many newer immunosuppressive agents will be developed that target specific critical pathways in the immune response to the allograft. These advances should lead to more focused immunosuppression, greater drug synergism, reduction in the doses of individual agents, steroid-sparing regimens, and reduction in end-organ toxicities. The ultimate goal will be to define a perioperative therapeutic regimen that will result in a state of " transplantation tolerance," in which the patient will indefinitely accept their allograft without the need for chronic immunosuppressive therapy.

Tacrolimus: a further update of its use in the management of organ transplantation

Extensive clinical use has confirmed that tacrolimus (Prograf) is a key option for immunosuppression after transplantation. In large, prospective, randomised, multicentre trials in adults and children receiving solid organ transplants, tacrolimus was at least as effective or provided better efficacy than cyclosporin microemulsion in terms of patient and graft survival, treatment failure rates and the incidence of biopsy-proven acute and corticosteroid-resistant rejection episodes. Notably, the lower incidence of rejection episodes after renal transplantation in tacrolimus recipients was reflected in improved cost effectiveness. In bone marrow transplant (BMT) recipients, the incidence of tacrolimus grade II-IV graft-versus-host disease was significantly lower with tacrolimus than cyclosporin treatment. Efficacy was maintained in renal and liver transplant recipients after total withdrawal of corticosteroid therapy from tacrolimus-based immunosuppression, with the incidence of acute rejection episodes at up to 2 years' follow-up being similar with or without corticosteroids. Tacrolimus provided effective rescue therapy in transplant recipients with persistent acute or chronic allograft rejection or drug-related toxicity associated with cyclosporin treatment. Typically, conversion to tacrolimus reversed rejection episodes and/or improved the tolerability profile, particularly in terms of reduced hyperlipidaemia. In lung transplant recipients with obliterative bronchiolitis, conversion to tacrolimus reduced the decline in and/or improved lung function in terms of forced expiratory volume in 1 second. Tolerability issues may be a factor when choosing a calcineurin inhibitor. Cyclosporin tends to be associated with a higher incidence of significant hypertension, hyperlipidaemia, hirsutism, gingivitis and gum hyperplasia, whereas the incidence of some types of neurotoxicity, disturbances in glucose metabolism, diarrhoea, pruritus and alopecia may be higher with tacrolimus treatment. Renal function, as assessed by serum creatinine levels and glomerular filtration rates, was better in tacrolimus than cyclosporin recipients at up to 5 years' follow-up.

CONCLUSION

Recent well designed trials have consolidated the place of tacrolimus as an important choice for primary immunosuppression in solid organ transplantation and in BMT. Notably, in adults and children receiving transplants, tacrolimus-based primary immunosuppression was at least as effective or provided better efficacy than cyclosporin microemulsion treatment in terms of patient and graft survival, treatment failure and the incidence of acute and corticosteroid-resistant rejection episodes. The reduced incidence of rejection episodes in renal transplant recipients receiving tacrolimus translated into a better cost effectiveness relative to cyclosporin microemulsion treatment. The optimal immunosuppression regimen is ultimately dependent on balancing such factors as the efficacy of the individual drugs, their tolerability, potential for drug interactions and pharmacoeconomic issues.