Infant heart transplantation: improved intermediate results

Total donor ischemic time: relationship to early hemodynamics and intensive care morbidity in pediatric cardiac transplant recipients

OBJECTIVE

Single-center studies have failed to link modest increases in total donor ischemic time to mortality after pediatric orthotopic heart transplant. We aimed to investigate whether prolonged total donor ischemic time is linked to pediatric intensive care morbidity after orthotopic heart transplant.

DESIGN

Retrospective cohort review.

SETTING

Tertiary pediatric transplant center in the United Kingdom.

PATIENTS

Ninety-three pediatric orthotopic heart transplants between 2002 and 2006.

METHODS

Total donor ischemic time was investigated for association with early post-orthotopic heart transplant hemodynamics and intensive care unit morbidities.

RESULTS

Of 43 males and 50 females with median age 7.2 (interquartile range 2.2, 13.0) yrs, 62 (68%) had dilated cardiomyopathy, 20 (22%) had congenital heart disease, and nine (10%) had restrictive cardiomyopathy. The mean total donor ischemic time was 225.9 (sd 65.6) mins. In the first 24 hrs after orthotopic heart transplant, age-adjusted mean arterial blood pressure increased (p < .001), mean pulmonary arterial pressure fell (p = .012), but central venous pressure (p = .58) and left atrial pressure (p = .20) were unchanged. After adjustment for age, primary diagnosis, pre-orthotopic heart transplant mechanical support, and marginal donor factors, longer total donor ischemic time was significantly associated with lower mean arterial blood pressure (p < .001) in the first 24 hrs after orthotopic heart transplant, longer post-orthotopic heart transplant mechanical ventilation (p = .03), longer post-orthotopic heart transplant stay in the intensive care unit (p = .004), and longer post-orthotopic heart transplant stay in hospital (p = .02). Total donor ischemic time was not related to levels of mean pulmonary arterial pressure (p = .62), left atrial pressure (p = .38), or central venous pressure (p = .76) early after orthotopic heart transplant.

CONCLUSIONS

Prolonged total donor ischemic time has an adverse effect on the donor organ, contributing to lower mean arterial blood pressure, as well as more prolonged ventilation and intensive care unit and hospital stays post-orthotopic heart transplant, reflecting increased morbidity.

Heart Transplantation for Congenital Heart Disease

Congenital heart disease affects 0.8% of all live-born infants. Some of the malformed hearts can at best be palliated by conventional surgical or catheter interventions from the start. Others fail slowly from chronic overloading. Patients with congenital heart disease have been among the first transplant recipients since 1967. Primary therapy with infant heart transplant is a convincing concept from an immunological perspective but large-scale implementation is limited by donor organ shortages. Another growing area is rescue therapy for older patients with end-stage heart failure after palliative procedures, particularly those with single-ventricle hearts, systemic right ventricles, and associated arrhythmias.

Pediatric cardiac retransplant: differing patterns of primary graft failure by age at first transplant

OBJECTIVE

This study compared graft failure leading to retransplant in infants versus older children at initial heart transplant.

METHODS

Twenty-six retransplant recipients were compared by age at first transplant: infant group (<1 year) and pediatric group (≥1 year).

RESULTS

Early retransplant survival was 92%. Retransplant survivals at 1, 3, and 5 years were 83%, 74%, and 67%. There were 15 infant and 11 pediatric patients. First transplant ages were 0.4 ± 0.3 vs. 8.5 ± 5.7 years in infant and pediatric groups, respectively (P < .01). First graft rejection episodes were more common in pediatric group (4.8 ± 2.5 vs 3.1 ± 2.1, P = .032), and rejection rate was higher (1.5 ± 1.1 vs 0.4 ± 0.4, P = .0024). Median first graft survival was longer in infant group (10.7 years vs 3.9 years, P < .001). Recurrent cellular rejection was retransplant indication in 40% of infant group versus 91% of pediatric group (P < .05). Cardiac allograft vasculopathy was more prevalent in infant group (73% vs 20% in pediatric group, P = .032).

CONCLUSIONS

Infant heart transplant recipients had longer primary graft survival, fewer cellular rejection episodes, and higher incidence of cardiac allograft vasculopathy relative to older graft recipients requiring retransplant. Advantages in adaptive immunity in infant heart recipients confer improved primary graft survival, but longer graft life in these patients is limited by cardiac allograft vasculopathy. Older recipient first graft failure was rejection related, and shorter graft life probably limited development of cardiac allograft vasculopathy.

Birth Weight and Complexity Are Significant Factors for the Management of Hypoplastic Left Heart Syndrome

BACKGROUND

Classic options for treatment of hypoplastic left heart syndrome include the Norwood procedure (NW) and heart transplantation (HT). Recently off-pump palliative procedures were introduced in the management of these patients. Risk factors influencing the decision between the NW with staged reconstruction or off-pump palliation and HT were assessed.

METHODS

Between January 2002 and January 2006, 69 patients with hypoplastic left heart syndrome were referred for either a NW (n = 33) or HT (n = 36). Patients referred for HT underwent off-pump palliation (catheter-based, n = 20, or surgical hybrid procedures, n = 7) until a donor organ became available: including patent ductus arteriosus stenting (80.6%), atrial septostomy (41.7%), and branch pulmonary artery banding (55.6%).

RESULTS

Heart transplantation patients were more complex, based on a higher Aristotle Comprehensive Complexity score calculated at birth (HT 18.8 +/- 2.4 versus NW 17.7 +/- 1.7; p < 0.05). Presurgical death was significantly greater for HT referrals (HT 27.8% versus NW 3.0%; p < 0.01); however, there was no difference between the two groups in operative (HT 11.5% versus NW 21.9%; not significant) or overall mortality (HT 36.1% versus NW 24.2%; not significant). No independent risk factors for death were identified with HT; however, a lower birth weight (<2.5 kg) and a higher Aristotle score (>20) correlated with surgical death with NW (p < 0.01). Noticeably, surgical survival was 85.7% for infants with birth weight of 2.5 kg or greater undergoing NW.

CONCLUSIONS

Overall survival is similar for hypoplastic left heart syndrome patients referred for the NW or HT. Lower birth weight and higher complexity are risk factors for patients undergoing NW. Off-pump palliation followed by HT or further staged palliation should be considered for these high-risk hypoplastic left heart syndrome patients.

Pediatric cardiac transplantation

Pediatric heart transplantation has undergone major changes over the past two decades, marked by a substantial improvement in survival, reduction in posttransplant complications, and enhancement in quality of life for transplant recipients. Actuarial survival has improved substantially in the last decade. Indications for pediatric heart transplant have changed as surgery for complex congenital heart lesions has evolved. There are now left and right ventricular assist devices that are suitable for use in infants as a bridge to transplantation. New immunosuppressive agents have reduced the risk of rejection while minimizing side effects and strategies to reduce the risk of graft coronary disease are beginning to show promise. Finally, true long-term survival for children after heart transplant has now been demonstrated and quality of life is excellent.

New directions in cardiac transplantation

More than three decades of clinical experience in cardiac transplantation resulted in the spread of the procedure worldwide with a wealth of knowledge and advancements. Developments included liberalization of recipient and donor selection criteria, improved surgical techniques, novel immunosuppressive drugs and protocols, new rejection surveillance techniques, and better understanding of the pathophysiology of cardiac allograft vasculopathy to direct interventions for prevention and treatment.

Heart transplantation in children after mechanical circulatory support with pulsatile pneumatic assist device

BACKGROUND

Mechanical support with a pulsatile pneumatic ventricular assist device (VAD) is a complex rescue procedure performed in children with untreatable cardiogenic shock. Its impact on early and long-term survival after subsequent heart transplantation (HTx) remains to be determined.

METHODS

We reviewed retrospectively the course of 95 children (median age, 8 years; range, 8 days-17 years; body weight, 24 kg; range, 3-110 kg) who underwent HTx. Group A, the elective-HTx group, consists of 33 children who were treated as outpatients before transplantation. Group B, the emergency-HTx group, has 44 children who were critically ill and hospitalized before transplantation but without ventricular assist devices, whereas Group C, the VAD-HTx group, consists of 18 children resuscitated and supported with pulsatile pneumatic VADs for a median time of 20 days.

RESULTS

Overall actuarial survival after cardiac transplantation was 86% at 1 month, 82% at 1 year, and 78% at 5 years, without significant differences among the 3 sub-groups. Group A had the best long-term survival rate, 88% at 1 month, 88% at 1 year, and 80% at 5 years. Group B had a survival rate of 88% at 1 month, 82% at 1 year, and 79% at 5 years. Group C had a survival rate of 72% at 1 month, 72% at 1 year, and 72% at 5 years. We found no differences in neurologic outcome, acute cardiac rejection, or transplant failure. The survival rate was significantly better in the children with cardiomyopathy compared with those with congenital heart defects (p = 0.014).

CONCLUSIONS

Bridging to HTx with a pulsatile pneumatic VAD is a safe procedure in pediatric patients. After HTx, overall survival of these children is similar to that of patients who were bridged with inotropes or who were awaiting heart transplantation electively.

Anaesthetic and perioperative management of paediatric organ recipients in nontransplant surgery

The number and success rate of paediatric organ transplantation continue to improve yearly, and the number of transplanted children presenting for either elective or emergency nontransplant surgery is expected to increase accordingly. The general considerations related to any transplant recipient are the physiological and pharmacological problems of allograft denervation, the side effects of immunosuppression, the risk of infection, and the potential for rejection. Preoperative assessment of transplant recipients undergoing non-transplant surgery should focus on graft function, the risk of infection, and function of other organs. Local, regional, or general anaesthesia can be safely delivered to transplant recipients. Specific anaesthetic considerations related to the type of transplantation, have an impact directly on anaesthetic and perioperative management. Since anaesthetists and surgeons in hospitals who are not involved in transplantations, may be required to manage paediatric transplant recipients, the reviews of the existing experience in this field will be valuable tools in their hands.

Quality of life and function following cardiac transplantation in adolescents

Quality of life and functional status are important outcome measures following heart transplantation. The present study evaluated the quality of life and function of 10 adolescent heart transplant recipients at the Hospital for Sick Children. Subjects were surveyed using a visual analog quality of life scale, the Children's Depression Inventory, The Pediatric Quality of Life Scale 4.0, and the Functional Status IIR. Results demonstrated excellent perceived quality of life and psychologic well-being, comparable to healthy norms. Subscale results for physical, social, and emotional function provide evidence for positive responses to transplantation. As well, results on factors such as self-esteem, school, interpersonal function, and mood demonstrate gender differences that may influence outcomes. Studies are currently underway to further delineate these important quality of life, function, and psychosocial issues to ensure optimal outcomes are achieved in our patients.

Heart transplantation in the young and elderly

INTRODUCTION

Heart transplantation has become an acceptable treatment in pediatric patients with end-stage heart disease and complex congenital heart disease. The liberalization of recipient eligibility criteria, mainly age, along with the expansion of the donor pool has resulted in the acceptable transplantation of older recipients.

METHODS

Between July 1994 and June 1998, 39 pediatric patients aged 16 days to 17.6 years (median 6.68 years) and 123 elderly patients aged 60 to 74.8 years (median 64.1 years) were transplanted at our institution. In the pediatric group, 19 had idiopathic dilated cardiomyopathy (DCM) (46 %), 14 had congenital heart disease (34 %), 4 had other etiologies of cardiomyopathy (10 %), 2 had transplant coronary artery disease (TCAD) (5 %), and 1 each had acute rejection and graft failure. In the elderly group, 71 had ischemic cardiomyopathy (58 %), 38 had DCM (31 %), 9 had other forms of cardiomyopathy (7 %), and 5 had TCAD (4 %).

RESULTS

Thirty-day, 1-year, and 4-year survival was 97.4 %, 87.2 %, and 70.9 % for the pediatric group and 92.7 %, 81.3 %, and 79.3 % for the elderly group. One and 4-year freedom from TCAD was 100.0 % and 85.3 % for the pediatric group and 91.9 % and 83.3 % for the elderly group.

CONCLUSIONS

[emsp3 ]Orthotopic heart transplantation is effective for the treatment of irreparable congenital and end-stage heart disease. It provides excellent long-term results in both the very young and elderly.

Nonadherence is associated with late rejection in pediatric heart transplant recipients

OBJECTIVES

The objective was to study the impact of nonadherence on late rejection after pediatric heart transplantation.

STUDY DESIGN

This was a retrospective cohort study of cardiac transplant recipients surviving >6 months (n = 50). Patients were stratified by episodes of late rejection. End points were defined by cyclosporin A (CSA) level, CSA level variability, and patient admission of nonadherence.

RESULTS

In 15 patients there were 49 episodes of late rejection, and 37 (76%) were associated with nonadherence. Of these patients, 7 of 15 died, and 3 of 15 had transplant coronary artery disease. Risk factors for the rejection were single-parent home, non-white, older age, and higher CSA level variability. In 35 nonrejectors there were 4 deaths from sepsis, post-transplant lymphoproliferative disease, renal failure, and encephalomyelitis.

CONCLUSION

Late rejection after pediatric heart transplantation is associated with nonadherence, is common during adolescence, and is associated with poor outcome.

Utility of extracorporeal membrane oxygenation for early graft failure following heart transplantation in infancy

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) is widely used for postcardiotomy cardiogenic shock in children. However, the efficacy of ECMO for early post-heart transplant graft failure in infants has not been reported. Our aims were to determine: (1) the utility of ECMO in infants with severe donor-heart dysfunction, (2) predictors for requiring ECMO, and (3) the long-term outcome of surviving ECMO patients.

METHODS

All infants (age < 6 months at listing) undergoing heart transplantation were reviewed. Diagnostic categories were hypoplastic left heart syndrome (HLHS) and non-HLHS (complex congenital heart disease and cardiomyopathies). Continuous and categorical comparisons were by Wilcoxon's rank sum test and Fisher's exact test respectively.

RESULTS

14 (12 HLHS, 2 non-HLHS) of 63 (46 HLHS, 17 non-HLHS) infants were placed on ECMO. Ten patients (71%) were successfully weaned from ECMO and 8 (57%) were discharged alive. All ECMO hospital survivors remain alive (mean follow-up 36.2 +/- 21.4 months, range 13.1-77.6 months). Mean duration of ECMO support was 68 hours in weaned patients vs 144 hours (p = 0.19) in nonweaned patients, and 64 hours in survivors vs 123 hours (p = 0.35) in nonsurvivors. ECMO deaths were due to sepsis (n = 3), intractable pulmonary hypertension (n = 2), and intracranial bleed (n = 1). Neurologic deficits occurred in 2 survivors. Median ICU and hospital stays for ECMO survivors were 29 and 33 days vs 7 (p = 0.0003) and 9 (p = 0.0004) days for non-ECMO patients. Age listed, age transplanted, wait time, body weight, donor/recipient weight ratio, total ischemia time, and diagnosis did not predict the need for ECMO.

CONCLUSIONS

(1) ECMO is useful for post-heart transplant circulatory support in infants with early graft failure. (2) All survivors were weaned in fewer than 4 days. (3) Three-year survival of ECMO hospital survivors has been high, but neurologic complications are prevalent.

Preoperative assessment and management of pediatric heart transplantation

The period of preoperative management of the pediatric cardiac transplant patient can be divided into three phases: determination of transplant feasibility, listing, and medical management. Chronic infection, irreversible elevation of pulmonary vascular resistance, and intractable disease in other organ systems may all be contraindications for transplantation. The United Network for Organ Sharing has recently changed its listing guidelines. Adolescent donors are now preferentially, to some extent, allocated to adolescent recipients. Management of pediatric patients awaiting cardiac transplantation encompasses optimization of cardiac output through the use of vasodilators and oral and intravenous inotropic agents. For those patients listed for transplantation who have single ventricle lesions, such as hypoplastic left heart syndrome, management of heart failure also includes balancing systemic and pulmonary blood flows. Mechanical support of the circulation with extracorporeal membrane oxygenation or ventricular assist devices can be used as a bridge to transplant in pediatric patients.

Advances in pediatric cardiac surgery

During the past year there have been many important scientific and clinical publications addressing important aspects of pediatric cardiac surgery. Herein we review some of the more significant contributions, with our own commentary added. Space limitations prevent a more comprehensive review.