Heart transplantation in children

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.

Outcome of children with end-stage congenital heart disease waiting for cardiac transplantation

BACKGROUND

End-stage congenital heart disease (CHD) is a major indication for pediatric cardiac transplantation. The objective of the study was to evaluate pre-transplant outcome of children with CHD.

METHODS

The clinical profile and outcome of patients with CHD <20 years of age listed for transplantation (1993 to 1999) were reviewed and patients who died waiting (Group I) were compared with survivors to transplant (Group II).

RESULTS

Mean age of the patients (n = 46) was 8.3 +/- 8 years. Primary indications for transplant were ventricular dysfunction in 36 (78%), failed Fontan in 8 (18%) and severe hypoxemia in 2 (4%) patients. Thirty-two patients were Status 1 (70%), 14 were Status 2 and 5 patients were de-listed. Twenty-nine of the 41 patients that remained listed survived to transplant, 12 (29%) died waiting. Causes of death were sepsis in 2 and severe heart failure (HF) in 10 patients. Eight patients died with multi-system organ failure, including 3 on mechanical circulatory support. Mean time to death was 29 +/- 28 days and time to transplant was 94 +/- 176 days. Mean age at listing was younger in Group I (2.6 +/- 4 years) compared with Group II (9.1 +/- 7 years, p < 0.05). Mean HF duration was shorter in Group I (3.6 +/- 3.9 months) compared with Group II (25 +/- 33 months, p < 0.05). Fifty-day actuarial survival on the waiting list was lower in infants (38%) compared with older children (91%, p < 0.05). In contrast to the high mortality (71%) in infants with CHD, all infants with cardiomyopathy survived to transplant.

CONCLUSIONS

Seventy-one percent of patients listed with CHD survived to transplant. Younger age at listing and rapid onset of HF were significant risk factors for pre-transplant mortality.

Anesthetic Management of Pediatric Cardiac Transplantation

Cardiac transplantation has become a widely accepted ther apy for a variety of end-stage cardiac diseases in pediatric patients. From November 1985 to November 1999, 347 pe diatric cardiac transplantations were performed at Loma Linda University Medical Center (LLUMC), including 235 in children younger than 6 months of age. It is essential to be familiar with the physiologic and anatomic characteristics of the recipient. Hypoplastic left heart syndrome is the most frequent congenital disorder leading to transplant in neo nates at LLUMC, with diseases presenting with left ventric ular failure accounting for the majority of the remainder of patients. We have assessed many variables for a possible relationship to intraoperative or postoperative compli cations, including anesthetic induction and maintenance agents, pH and base excess, as determined by arterial blood gas analysis before cardiopulmonary bypass (CPB), and he modynamic changes requiring treatment before CPB. Al though we have noticed an association between low patient temperature or mechanical stimulation at the time of ster notomy, and hemodynamic complications before CPB, in our experience no single anesthetic technique or intraoper ative event, including ventricular fibrillation, predicts early mortality. We believe anesthetic management of pediatric cardiac transplant recipients should be tailored to fit the pathophysiology present.

Cardiomyopathy and heart transplantation in children

Cardiomyopathy is one of the most common causes of death in children with heart disease. Increasingly, dilated cardiomyopathy is recognized to be familial, and specific gene products related to the myocyte cytoskeleton and contractile proteins have been identified. Other associations with metabolic disease, dysmorphic syndromes, and neuromuscular disease are important to establish, particularly in pediatric patients, to guide therapy and patient selection for transplantation. Survival in children with dilated cardiomyopathy depends on accurate diagnosis and aggressive therapy. Patients may respond to conventional treatment for heart failure or may deteriorate, requiring mechanical support. Extracorporeal membrane oxygenation has been used effectively for mechanical support in children until improvement occurs or as a bridge to transplantation. For those who are listed, the mortality rate while waiting for a donor organ averages approximately 20%. Survival after transplantation is good, with an intermediate survival rate of approximately 70%. Late survival remains to be determined in the current cyclosporin era but may in fact be improving. However, increased organ donation or strategies to increase the size of the organ donor pool, such as xenotransplantation, are needed to significantly reduce the rate of mortality while waiting.

Survival after listing for cardiac transplantation in children

Despite improvement in surgical and medical management of children with congenital and acquired heart disease, cardiac transplantation remains an important therapeutic option for infants and children with end-stage heart disease. Ultimate survival in patients who are listed for transplantation is a function of both mortality while awaiting transplantation and survival after transplantation. Survival of heart transplantation is affected by the severity of illness before transplantation, the unique pathophysiology of certain defects, and the availability of donor hearts. Outcome following listing for transplantation is best studied with the use of recent modifications in statistical methods of competing outcomes analysis. By this analysis a predicted mortality while waiting among all pediatric patients is 20% at 1 year, with 67% undergoing transplantation, 10% still on the list awaiting transplant, and 3% removed from the list. Among infants, most of them with hypoplastic left heart syndrome, 60% will have transplantation by 6 months after listing, with 27% of patients dying while waiting. In infants the major risk factors for death while waiting are the need for inotropic support at listing, smaller size, and recipient blood type. In older children risk factors for death while waiting are Status 1 at listing and a need for mechanical ventilation. Intermediate-term survival after transplant is excellent in all age groups with 86% alive at 6 months, 84% at 1 year, and 73% at 5 years. Survival after transplant in infants is comparable to survival in older children, although the early mortality after transplantation is greater. Infants who have recently undergone sternotomy or received organs from donors who did not die of closed head trauma are more likely to die early after transplant. Among older children risk factors for death after transplantation include the need for a mechanical support device or a younger age in patients greater than 1 year of age. Death following transplantation is primarily related to early graft failure in infants, whereas rejection, infection, and sudden death account for the majority of deaths in older children. Although improved immunosuppressive agents promise to lead to even better survival rates after transplantation, greater access to donors is essential if overall survival is to be improved.

Heart transplantation in children with congenital heart disease

OBJECTIVES

The aim of this study was to describe heart transplantation in children with congenital heart disease and to compare the results with those in children undergoing transplantation for other cardiac diseases.

BACKGROUND

Reports describe decreased survival after heart transplantation in children with congenital heart disease compared with those with cardiomyopathy. However, transplantation is increasingly being considered in the surgical management of children with complex congenital heart disease. Present-day results from this group require reassessment.

METHODS

The diagnoses, previous operations and indications for transplantation were characterized in children with congenital heart disease. Pretransplant course, graft ischemia time, post-transplant survival and outcome (rejection frequency, infection rate, length of hospital stay) were compared with those in children undergoing transplantation for other reasons (n = 47).

RESULTS

Thirty-seven children (mean [+/- SD] age 9 +/- 6 years) with congenital heart disease underwent transplantation; 86% had undergone one or more previous operations. Repair of extracardiac defects at transplantation was necessary in 23 patients. Causes of death after transplantation were donor failure in two patients, surgical bleeding in two, pulmonary hemorrhage in one, infection in four, rejection in three and graft atherosclerosis in one. No difference in 1- and 5-year survival rates (70% vs. 77% and 64% vs. 65%, respectively), rejection frequency or length of hospital stay was seen between children with and without congenital heart disease. Cardiopulmonary bypass and donor ischemia time were significantly longer in patients with congenital heart disease. Serious infections were more common in children with than without congenital heart disease (13 of 37 vs. 6 of 47, respectively, p = 0.01).

CONCLUSIONS

Despite the more complex cardiac surgery required at implantation and longer donor ischemic time, heart transplantation can be performed in children with complex congenital heart disease with success similar to that in patients with other cardiac diseases.