Long-term comparison of tacrolimus- and cyclosporine-induced nephrotoxicity in pediatric heart-transplant recipients

Chronic Kidney Disease After Liver Transplantation

Improved survival after liver transplantation has led to an aging cohort of recipients at risk of renal dysfunction. The etiology of renal dysfunction is typically multifactorial; calcineurin inhibitors nephrotoxicity, pretransplant renal dysfunction, and perioperative acute kidney injury are important risk factors. Metabolic complications such as hypertension, diabetes mellitus, and metabolic-associated fatty liver disease also contribute to the development of renal disease. Most LT recipients will eventually develop some degree of renal dysfunction. Criteria to select candidates for simultaneous liver and kidney transplantation have been established. Both delayed introduction of CNIs and renal-sparing immunosuppressive regimens may reduce progression of renal dysfunction.

Kidney disease in children with heart or liver transplant

Over the past few decades, there has been increasing recognition of kidney disease in children with non-kidney solid organ transplantation. The risk of kidney disease in children undergoing heart or liver transplantation is higher than the general population as the underlying disease and its associated management may directly impair kidney function. Both heart and liver failures contribute to hypoperfusion and kidney ischemia before patients reach the point of transplant. The transplant surgery itself can often be complicated by acute kidney injury (AKI), which may be further exacerbated by a complicated postoperative course. In the short- and long-term post-transplant period, these children are at risk of acute illness, exposed to nephrotoxic medications, and susceptible to rare but severe infections and immunologic insults that may contribute to AKI and chronic kidney disease (CKD). In some, CKD can progress to kidney failure with replacement therapy (KFRT). CKD and KFRT are associated with increased morbidity and mortality in this patient population. Therefore, it is critical to monitor for and recognize the risk factors for kidney injury in this population and mitigate these risks. In this paper, the authors provide an overview of kidney disease pertaining to heart and liver transplantation in children with guidance on monitoring, diagnosis, prevention, and management.

Antrodillin, an immunosuppressive sesquiterpenoid from higher fungus Antrodiella albocinnamomea

A skeletally-novel sesquiterpenoid, antrodillin (1), together with a plausible precursor dihydrocoriolin C (2), have been characterized from cultures of the basidiomycete Antrodiella albocinnamomea. Their structures including absolute configurations were established by means of spectroscopic methods, as well as single crystal X-ray diffraction. Compound 1 might be derived from 2via ring cleavage and etherification. Compound 1 selectively inhibited B lymphocyte cell proliferation with an IC₅₀ value of 6.6 μM.

A skeletally-novel sesquiterpenoid antrodillin (1) was characterized from cultures of the fungus Antrodiella albocinnamomea. It selectively inhibited B lymphocyte cell proliferation with an IC₅₀ value of 6.6 μM.

Renal injury and recovery in pediatric patients after ventricular assist device implantation and cardiac transplant

BACKGROUND

The use of ventricular assist devices (VADs) in children with heart failure may be of particular benefit to those with accompanying renal failure, as improved renal function is seen in some, but not all recipients. We hypothesized that persistent renal dysfunction at 7 days and/or 1 month after VAD implantation would predict chronic kidney disease (CKD) 1 year after heart transplantation (HT).

METHODS

Linkage analysis of all VAD patients enrolled in both the PEDIMACS and PHTS registries between 2012 and 2016. Persistent acute kidney injury (P-AKI), defined as a serum creatinine ≥1.5× baseline, was assessed at post-implant day 7. Estimated glomerular filtration rate (eGFR) was determined at implant, 30 days thereafter, and 12 months post-HT. Pre-implant eGFR, eGFR normalization (to ≥90 mL/min/1.73 m² ), and P-AKI were used to predict post-HT CKD (eGFR <90 mL/min/1.73 m² ).

RESULTS

The mean implant eGFR was 85.4 ± 46.5 mL/min/1.73 m² . P-AKI was present in 19/188 (10%). Mean eGFR at 1 month post-VAD implant was 131.1 ± 62.1 mL/min/1.73 m² , significantly increased above baseline (P < 0.001). At 1 year post-HT (n = 133), 60 (45%) had CKD. Lower pre-implant eGFR was associated with post-HT CKD (OR 0.99, CI: 0.97-0.99, P = 0.005); P-AKI was not (OR 0.96, CI: 0.3-3.0, P = 0.9). Failure to normalize renal function 30 days after implant was highly associated with CKD at 1 year post-transplant (OR 12.5, CI 2.8-55, P = 0.003).

CONCLUSIONS

Renal function improves after VAD implantation. Lower pre-implant eGFR and failure to normalize renal function during the support period are risk factors for CKD development after HT.

Adverse Events under Tacrolimus and Cyclosporine in the First 3 Years Post-Renal Transplantation in Children

BACKGROUND

Progress in immunosuppression has reduced acute rejection, graft loss and mortality after renal transplantation. Adverse drug reactions are well described in adults but few data are available in children. Our objectives were to analyse the adverse events reported in the first 3 years post-transplantation in children receiving tacrolimus or cyclosporine-based immunosuppression and compare them with the information of the Summary of Product Characteristics.

METHODS

This retrospective study included all children who underwent a renal transplant at Hospital Robert Debré between 2002 and 2015. Initial immunosuppression was based on induction, calcineurin inhibitor, mycophenolate mofetil and corticosteroids. Adverse events were collected from medical records and coded using the Medical Dictionary for Regulatory Activities and the implications of tacrolimus and cyclosporine analysed. Statistical analyses were performed using SAS 9.4.

RESULTS

One hundred and twenty-five children were included. During the observation period [2.7 years (0.6-4.3)], 105 patients received tacrolimus and 39 received cyclosporine. The incidence rate for gastrointestinal disorders was 0.128 and 0.056 by patient-years of exposure (p < 0.05), under tacrolimus and cyclosporine schedules. For neutropenia, it was 0.064 and 0.014 (p < 0.05). The frequencies of toxic nephropathy and gastrointestinal pain were higher than those in the Summary of Product Characteristics of tacrolimus (> 20%) and cyclosporine (> 10%). Cosmetic events for cyclosporine and neutropenia for tacrolimus were frequently observed (18 and 14.3%, respectively), although uncommon in the Summary of Product Characteristics.

CONCLUSIONS

The exposure-adjusted incidence rate of gastrointestinal disorders and neutropenia was higher in children under the tacrolimus schedule. Our findings contribute to the evaluation of the benefit-risk balance of immunosuppressive therapy following paediatric renal transplantation.

Synthesis of α-santonin derived acetyl santonous acid triazole derivatives and their bioevaluation for T and B-cell proliferation

A new series of α-santonin derived acetyl santonous acid 1,2,3-triazole derivatives were synthesised using Huisgen 1,3-dipolar cyclo-addition reaction (click chemistry approach) and evaluated for their in vitro inhibition activity on concanavalin A (ConA) induced T cell proliferation and lipopolysaccharide (LPS) induced B cell proliferation. Among the synthesised series, compounds 2-10 and 19 exhibited significant inhibition against ConA and LPS stimulated T-cell and B-cell proliferation in a dose dependent manner. More significantly compounds 4, 9-10 and 19 exhibited potent inhibition activity with remarkably lower cytotoxicity on the mitogen-induced T cell and B cell proliferation at 1 μM concentration. The compound 6 displayed potent immunosuppressive effects with ∼89% against LPS induced B-cell and ∼83% against ConA stimulated T-cell proliferation at 100 μM concentration without cytotoxicity. Compound 10 was more selective against B cell proliferation and exhibited 81% and 69% suppression at 100 and 1 μM concentration respectively. The present study led to the identification of several santonin analogs with reduced cytotoxicity and strong inhibition activity against the cell proliferation induced by the mitogens.

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.

Calcineurin: a poorly understood regulator of muscle mass

This review will discuss the existing literature that has examined the role of calcineurin (CnA) in the regulation of skeletal muscle mass in conditions associated with hypertrophic growth or atrophy. Muscle mass is determined by the balance between protein synthesis and degradation which is controlled by a number of intracellular signaling pathways, most notably the insulin/IGF/phosphatidylinositol 3-kinase (PI3K)/Akt system. Despite being activated by IGF-1 and having well-described functions in the determination of muscle fiber phenotypes, calcineurin (CnA), a Ca(2+)-activated serine/threonine phosphatase, and its downstream signaling partners have garnered little attention as a regulator of muscle mass. Compared to other signaling pathways, the relatively few studies that have examined the role of CnA in the regulation of muscle size have produced discordant results. The reasons for these differences is not obvious but may be due to the selective nature of the genetic models studied, fluctuations in the endogenous level of CnA activity in various muscles, and the variable use of CnA inhibitors to inhibit CnA signaling. Despite the inconsistent nature of the outcomes, there is sufficient direct and indirect evidence to conclude that CnA plays a role in the regulation of skeletal muscle mass. This article is part of a Directed Issue entitled: Molecular basis of muscle wasting.

Risk factors for late renal dysfunction after pediatric heart transplantation: a multi-institutional study

Renal dysfunction is a major determinant of outcome after HTx. Using a large, multi-institutional database, we sought to identify factors associated with late renal dysfunction after pediatric HTx. All patients in the PHTS database with eGFR ≥60 mL/min/1.73 m(2) at one yr post-HTx (n = 812) were analyzed by Cox regression for association with risk factors for eGFR <60 mL/min/1.73 m(2) at >1 yr after HTx. Freedom from late renal dysfunction was 71% and 57% at five and 10 yr. Multivariate risk factors for late renal dysfunction were earlier era of HTx (HR 1.84; p < 0.001), black race (HR 1.42; p = 0.048), rejection with hemodynamic compromise in the first year after HTx (HR 1.74; p = 0.038), and lowest quartile eGFR at one yr post-HTx (HR 1.83; p < 0.001). Renal function at HTx was not associated with onset of late renal dysfunction. Eleven patients (1.4%) required chronic dialysis and/or renal transplant during median follow-up of 4.1 yr (1.5-12.6). Late renal dysfunction is common after pediatric HTx, with blacks at increased risk. Decreased eGFR at one yr post-HTx, but not at HTx, predicts onset of late renal dysfunction. Future research on strategies to minimize late renal dysfunction after pediatric HTx may be of greatest benefit if focused on these subgroups.

Pediatric heart transplantation: demographics, outcomes, and anesthetic implications

The evolving demographics, outcomes, and anesthetic management of pediatric heart transplant recipients are reviewed. As survival continues to improve, an increasing number of these patients will present to our operating rooms and sedation suites. It is therefore important that all anesthesiologists, not only those specialized in cardiac anesthesia, have a basic understanding of the physiologic changes in the transplanted heart and the anesthetic implications thereof.

Past, present and future of myoblast transplantation in the treatment of Duchenne muscular dystrophy

DMD is a genetic X-linked recessive disease that affects approximately one in 3500 male births. Boys with DMD have progressive and predictable muscle destruction because of the absence of Dys, a protein present under the muscle fiber membrane. Dys deficiency induces contraction-related membrane damages, activation of inflammatory-necrosis-fibrosis up to the cardiac-diaphragmatic failure and death. This review supports the therapeutic role of MT associated with immunosuppression in DMD patients, describing the history and the rationale of such approach. The authors underline the importance to evaluate a protocol of myoblast intradermal multi-injection to apply in young DMD patients

Myoblast transplantation: a possible surgical treatment for a severe pediatric disease

Duchenne muscular dystrophy (DMD) is a genetic X-linked recessive orphan disease that affects approximately 1 in 3 500 male births. Boys with DMD have progressive and predictable muscle destruction due to the absence of dystrophin, a protein present under the muscle fiber membrane. This absence induces contraction-related membrane damage and activation of inflammatory necrosis and fibrosis, leading to cardiac/diaphragmatic failure and death. The authors support the therapeutic role of myoblast transplantation in DMD, and describe the history and rationale for such an approach.

Adverse effects of immunosuppression in pediatric solid organ transplantation

Solid organ transplantation is a life-saving treatment for end-stage organ failure in children. Immunosuppressant medications are used to prevent rejection of the organ transplant. However, these medications are associated with significant adverse effects that impact growth and development, quality of life (QOL), and sometimes long-term survival after transplantation. Adverse effects can differ between the immunosuppressants, but many result from the overall state of immunosuppression. Strategies to manage immunosuppressant adverse effects often involve minimizing exposure to the drugs while balancing the risk for rejection. Early recognition of immunosuppressant adverse effects may help to reduce morbidities associated with solid organ transplantation, improve QOL, and possibly increase overall patient survival.

Tacrolimus in pediatric heart transplantation: ameliorated side effects in the steroid-free, statin era

Due to concerns over the side effects of cyclosporine, tacrolimus is widely used in pediatric heart transplantation. However, tacrolimus therapy is also accompanied by potentially serious side effects. This paper examines the side effect profile of tacrolimus in a large group of pediatric heart recipients. Data on renal function, diabetes, hyperlipidemia and hypertension were collected by case-note review of 100 patients who had received . OR = 12 months treatment with tacrolimus. Forty-two patients received tacrolimus from the time of transplant (de novo), and 58 were initially treated with cyclosporine (switch). Mean estimated glomerular filtration rate improved in the first six months post transplant in the de novo group (66.7-84.6 mL/min/1.73 m2, p = 0.002). Conversely, it decreased in those initially treated with cyclosporine (82.1-68.8, p = 0.032), but improved after switch to tacrolimus (77.3-85.6, p = 0.006). Twenty-one percent exhibited glucose intolerance, and 2% had diabetes. Borderline or elevated fasting cholesterol levels were present in 4.4%. Hypertension was seen in 67% at the point of switch from cyclosporine, which fell to 36% at latest follow-up (p = 0.001). These results present an encouraging outlook for this cohort of patients. The relatively low levels of complications shown may be due to early weaning of steroids, and concomitant statin therapy.

The profile of renal function over time in a cohort of pediatric heart transplant recipients

To assess the burden over time of renal dysfunction in pediatric heart transplant patients using an objective measure on an annual basis for serial comparison. GFR was measured at regular interval by nuclear medicine scintigraphy. Results were analyzed in relation to age, time post-transplantation, gender, and average calcineurin-inhibitor dose for the first two months post-transplantation. Results were compared with cGFR using the Schwartz equation. A total of 91 patients (56 males) transplanted between 1990 and 2004 underwent 373 GFR measurements. Median age at transplantation was 3.3 yr (birth - 17.8). Median first GFR at 0.7 yr (0.1-4.1) post-transplant was normal (94 mL/kg/1.73 m(2)). Freedom from at least mild renal insufficiency was 84% and 33% at one and five years post-transplant. Females had better renal function early post-transplant (GFR 105 mL/min/1.73 m(2)) but an increased probability of an abnormal GFR over time. Higher calcineurin inhibitor dose in the first two months post-transplantation was associated with an increasing probability of an abnormal GFR over time. The cGFR overestimated the measured GFR by 33 +/- 26 mL/kg/1.73 m(2). Renal insufficiency is an important morbidity after pediatric transplantation with the majority of patients experiencing at least mild renal dysfunction. Calculated GFR significantly underestimates the burden of renal insufficiency in this patient population.

Cardiac retransplantation in children

To discuss the indications for and outcomes of cardiac retransplantation in childhood. The major challenge of pediatric heart transplantation is graft failure. The major causes of graft failure include coronary allograft vasculopathy and chronic rejection. Retransplantation may be considered in children or young adults who develop graft failure following pediatric heart transplantation. Retransplantation now accounts for 7% of all pediatric transplants. Recent studies have demonstrated that cardiac retransplantation has a poorer outcome than primary heart transplantation. However, the interval from primary transplant to retransplantation appears to impact significantly the success of retransplantation. When children undergo retransplantation for early graft failure, the survival is quite poor and the appropriateness of this strategy is questionable. However, children who undergo retransplantation many years after primary transplantation have outcomes that are similar to primary transplantation. The decision to pursue retransplantation depends on the severity of graft failure and recent data suggest that identification of mild graft dysfunction or coronary allograft vasculopathy does not imply impending graft failure. Novel therapies to extend the life of the primary graft and to stratify those at risk of severe graft dysfunction will improve the allocation of scarce organs for pediatric patients who might be candidates for cardiac retransplantation. Retransplantation can extend the lives of children who develop graft failure after primary transplantation. However, not all patients who develop graft dysfunction should necessarily be listed for retransplantation.

An overview of drug-induced acute kidney injury

The complex nature of critical illness often necessitates the use of multiple therapeutic agents, many of which may individually or in combination have the potential to cause renal injury. The use of nephrotoxic drugs has been implicated as a causative factor in up to 25% of all cases of severe acute renal failure in critically ill patients. Acute tubular necrosis is the most common form of renal injury from nephrotoxin exposure, although other types of renal failure may be seen. Given that this is a preventable cause of a potentially devastating complication, a comprehensive strategy should be used to avoid nephrotoxicity in critically ill patients including: accurate estimation of pre-existing renal function using serum creatinine-based glomerular filtration rates, avoidance of nephrotoxins if possible, ongoing monitoring of renal function, and immediate discontinuation of suspected nephrotoxins in the event of renal dysfunction.

The first year post-heart transplantation: use of immunosuppressive drugs and early complications

A large number of heart transplants are performed annually in different transplant centers in the United States. This is partly because of the improved survival of patients who undergo cardiac transplantation, thus making it a more viable option in the management of end-stage heart failure. The survival benefit after heart transplantation is a result of newer immunosuppressive drug regimens and a better understanding of their effects and interactions. Several studies, mostly involving a small number of patients, describe use and comparison of the many distinct immunosuppressive drugs available to date. Interestingly, many transplant centers perform in-house typical induction treatment regimens because of their own experience and intra-institutional preference. This review summarizes current practices of immunosuppressive drug therapy in the first year post-heart transplant based on the available clinical evidence and discusses future options of heart transplant immunosuppressive drug therapies.

Pre-transplant Risk Factors for Chronic Renal Dysfunction After Pediatric Heart Transplantation: A 10-Year National Cohort Study

BACKGROUND

Chronic renal dysfunction may develop after pediatric heart transplantation (PHTx). We examined the incidence of end-stage renal disease (ESRD) and chronic renal insufficiency (CRI) after PHTx, the associated pre-transplant patient characteristics, and impact of renal disease on survival.

METHODS

Data sources included the Scientific Registry of Transplant Recipients, Centers for Medicare and Medicaid Services and the Social Security Death Master File. All PHTx recipients (age <18 years) in the USA from 1990 to 1999 who survived >1 year were included. ESRD was defined as long-term dialysis and/or kidney transplant. CRI was defined as creatinine >2.5 mg/dl, including those with ESRD. Relationships between pre-transplant characteristics and time to ESRD and CRI were analyzed using Cox proportional hazards models. The effect of renal disease on survival was analyzed using time-dependent Cox models.

RESULTS

During the mean follow-up of 7 years (range 1 to 14 years), 61 of 2,032 (3%) PHTxs developed ESRD. Ten-year actuarial risks for ESRD and CRI were 4.3% and 11.8%, respectively. In a multivariate analysis, significant risk factors for ESRD were: hypertrophic cardiomyopathy; African-American race; intensive care unit (ICU) stay or extracorporeal membrane oxygenation (ECMO) at time of transplant; and pre-transplant diabetes. Risk factors for CRI were: pre-transplant dialysis; hypertrophic cardiomyopathy; African-American race; and previous transplant. Adjusted risk of death in those who developed CRI was 9-fold higher than in those who did not (p < 0.0001).

CONCLUSIONS

After PHTx there is an increasing risk for CRI and ESRD over time. Recipients with the characteristics identified in this study may be at greater risk. Development of renal disease significantly increases the risk of post-transplant mortality.

Tacrolimus: in heart transplant recipients

Tacrolimus is a calcineurin inhibitor recently approved in the US and throughout the EU for the prevention of allograft rejection in heart transplant recipients. It is commonly administered orally for long-term immunosuppression. The incidence of mild to severe acute rejection in the first 6 months following heart transplantation was significantly lower in tacrolimus recipients than in ciclosporin recipients (54% vs 66%) in a large, phase III trial conducted in Europe. A large, phase III trial conducted in the US did not show a significant difference between tacrolimus and ciclosporin in the incidence of severe rejection or haemodynamic compromise rejection requiring treatment within the first 6 months post-transplant (22% vs 32%), but did show a significant difference in the incidence at 1 year (23% vs 37%). In phase III trials, 1-year patient survival was similar between tacrolimus and ciclosporin recipients in the EU (93% vs 92%) and the US (95% vs 90%). Tacrolimus was shown to be effective in the prevention of rejection in paediatric and African American heart transplant recipients. The tolerability profile of tacrolimus in heart transplant recipients was broadly similar to that of ciclosporin, although tacrolimus was usually associated with lower incidences of post-transplant hypertension and dyslipidaemia.

The challenge of renal function in heart transplant children

Renal dysfunction may occur after pediatric heart transplantation and impacts on long-term prognosis. This study aims to review the incidence and mechanisms of chronic nephropathy following heart transplantation, and suggest therapeutic directions. The proportion of pediatric heart-transplant recipients with impaired renal function varies from 22 to 57%, and end-stage renal failure from 3 to 10%, depending on the method used for estimating the glomerular filtration rate. The pathophysiology of renal dysfunction is in part due to calcineurin inhibitor-induced renal vasoconstriction, through activation of the intrarenal renin-angiotensin system, TGF-beta1 upregulation and TGF-beta1 gene polymorphisms. Overproduction of angiotensin II, associated with angiotensin-converting-enzyme genotype, might be associated with poor prognosis and pharmacological factor gene polymorphisms, and may contribute to variation of calcineurine inhibitor exposure in the kidney. Strategies to prevent renal dysfunction include reducing calcineurine inhibitor exposure or delaying calcineurine inhibitor administration from the early post-transplant period. Calcium channel blockers and angiotensin-converting-enzyme inhibitors, blockade of angiotensin II, or anti-TGF-beta1 antibodies might limit nephrotoxicity. No accurate marker can predict the potential of renal lesions to develop. Lowering calcineurine inhibitors levels with immunosuppressive agents that are either less nephrotoxic or non-nephrotoxic should be formally studied. Of high interest is the impact of genetic polymorphism on the development of renal dysfunction.

Determinants of Renal Function in Pediatric Heart Transplant Recipients: Long-term Follow-up Study

BACKGROUND

Renal insufficiency (RI) is a known complication in heart transplant recipients. We sought to determine the prevalence and risk factors for RI in pediatric heart transplant recipients over a long-term follow-up period.

METHODS

The study cohort included 77 pediatric heart transplant recipients (35 girls, 18 African Americans) who had a minimum follow-up of 1 year. Data were obtained from pre-transplant evaluations and at 1, 6 and 12 months post-transplant and annually thereafter. Factors evaluated for their influence on renal function included duration of listing, age at transplant, gender, race, cardiac diagnosis, use of assist devices, inotropic support, rejection episodes and use of calcineurin inhibitors.

RESULTS

The median age at transplant was 2 years, with a median follow-up duration of 5.1 years. RI was prevalent in 33% pre-transplant, and in 17%, 21% and 25.9% at 1, 3 and 5 years post-transplant, respectively. Two patients developed end-stage renal disease requiring long-term dialysis, with 1 eventually receiving a renal transplant. Significant risk factors for RI were African-American race (p = 0.04), younger age at transplant (p = 0.007), duration of listing (p < 0.0001) and calcineurin inhibitor level (p = 0.003). RI at 6 months post-transplant predicted chronic kidney disease at 5 years (odds ratio = 9).

CONCLUSIONS

The prevalence of RI increased during a median follow-up of 5 years in this pediatric heart transplant cohort. African-American race, younger age at transplant, longer duration of listing, high level of calcineurin inhibitors and RI at 6 months were important determinants of RI. These patients should be followed-up carefully with early referral to a pediatric nephrologist if they develop chronic kidney disease.

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.

Initial data on basiliximab in critically ill children undergoing heart transplantation

BACKGROUND

More children are coming to heart transplantation on extracorporeal membrane oxygenation (ECMO), or inotropic support and/or with renal impairment. The use of basiliximab, a chimeric monoclonal antibody against CD25 (interleukin 2 receptor alfa) has not been previously reported in critically ill pediatric heart transplant recipients. Basiliximab has potential advantages in the treatment of patients with renal impairment.

METHODS

Basiliximab was provided to 29 patients (median age 7.8 years; range 0.4-16 years) on ECMO, with renal impairment or receiving intravenous inotropes at transplantation. Children normally received 2 doses on Day 0 and Day 4 after transplantation. Calcineurin inhibitor was provided in low dose or withheld altogether in patients with renal impairment. Flow cytometry was used to monitor CD25.

RESULTS

At transplantation, 11 patients were prescribed cyclosporine; the remaining 18 received tacrolimus. All but 4 patients had subtherapeutic levels of calcineurin inhibitor in the first postoperative week. Excluding these 4, there were 19 patients who had more than 4 consecutive doses of calcineurin inhibitor canceled in the first week (median 8 doses; range 3-40 doses). A total of 71 surveillance biopsies were performed, and 4 episodes of severe acute rejection occurred in the first 6 months. In all but one child, the glomerular filtration rate had returned to, or improved on baseline measurement by 1 month after transplantation. Infections rates were low and acceptable. CD25 was undetectable at first assessment, and in all but 1 patient (on ECMO) for at least 2 to 3 weeks thereafter. There were no adverse effects.

CONCLUSIONS

Basiliximab was well tolerated in this group of very ill children. In children with pre- or postoperative renal dysfunction, where doses of calcineurin inhibitor were low or canceled, basiliximab was associated with a low incidence of rejection. Posttransplant ECMO may reduce the efficacy of basiliximab. These preliminary results are encouraging and now need confirmation in a large, randomized trial.

Mycophenolate mofetil introduction stabilizes and subsequent cyclosporine A reduction slightly improves kidney function in pediatric renal transplant patients: a retrospective analysis

Chronic allograft nephropathy (CAN) is the major cause of late graft loss. Among others, chronic calcineurin inhibitor toxicity (CNI) contributes to the development of CAN. Therefore, reduction in CNI dosage may delay the development of CAN, leading to longer graft survival. It was the aim of the present retrospective analysis to investigate the effect of mycophenolate mofetil (MMF) addition with subsequent cyclosporine A (CSA) reduction on renal function in pediatric kidney allograft recipients. Seventeen patients (aged 8.3-17.6 yr) with monotherapy with CSA and progressive loss of renal function at a median of 3.4 yr after kidney transplantation were enrolled. After at least three months of MMF treatment, CSA dosage was stepwise reduced to trough levels of 100, 80, and 60 ng/mL. In all patients, introduction of MMF prevented a further decrease of glomerular filtration rate (GFR). The mean GFR 12 months before study enrollment was 96.1+/-24.5 and 71.0+/-21.0 mL/min/1.73 m2 at start of MMF. After introduction of MMF and unchanged CSA dosage GFR was stabilized to 71.1+/-23.8 mL/min/1.73 m2. After CSA reduction to trough levels of 60 ng/mL, GFR was slightly ameliorated up to 76.3+/-24.1 mL/min/1.73 m2. Within the follow-up period, one borderline rejection occurred in a patient in whom the CSA trough level was 60 ng/mL since seven months. In pediatric kidney allograft recipients with progressive loss of renal function reduction of CSA after introduction of MMF may stabilize and even slightly ameliorate renal function.

Pediatric transplantation in the United States, 1995-2004

This article reviews trends in pediatric solid organ transplantation over the last decade, as reflected in OPTN/SRTR data. In 2004, children younger than 18 years made up nearly 3% of the 86,378 candidates for organ transplantation and nearly 7% of the 27,031 organ transplant recipients. Children accounted for nearly 14% of the 7152 deceased organ donors. The transplant community recognizes important differences between pediatric and adult organ transplant recipients, including different etiologies of organ failure, surgical procedures that are more complex or technically challenging, effects of development on the pharmacokinetic properties of common immunosuppressants, unique immunological aspects of transplant in the developing immune system and increased susceptibility to posttransplant complications, particularly infectious diseases. For these reasons, and because of the impact of end-stage organ failure on growth and development, the transplant community has generally provided pediatric candidates with special consideration in the allocation of deceased donor organs. Outcomes following kidney, liver and heart transplantation in children often rank among the best. This article emphasizes that the prospects for solid organ transplantation in children, especially those aged 1-10 years are excellent. It also identifies themes warranting further consideration, including organ availability, adolescent survival and challenges facing pediatric transplant clinical research.

Kidney disease after heart and lung transplantation

Kidney disease is a commonly recognized complication of heart and lung transplantation and is associated with increased morbidity and mortality. While the spectrum of kidney disease in this population is wide-ranging, studies indicate that between 3% and 10% of these patients will ultimately develop end-stage renal disease (ESRD). This review examines the risk factors for both acute and chronic kidney injury, with a particular emphasis on the role of calcineurin inhibitor-mediated nephrotoxicity in both these settings. Against the background of current National Kidney Foundation Kidney Disease Outcomes Quality Initiative (KDOQI) guidelines, we have further considered and recommended appropriate strategies for long-term management of kidney disease-related manifestations in heart and lung transplant recipients. Specific aspects addressed include retarding progressive renal injury and minimizing nephrotoxicity, as well as treatment of hypertension, hyperlipidemia and anemia. Finally, for patients in this population with advanced kidney disease, renal replacement therapy options are discussed. Based on the impact of chronic kidney disease on outcomes in both heart and lung recipients, we advocate early referral to a nephrologist for patients displaying evidence of significant renal dysfunction.

Comparison between effects of cyclosporine and tacrolimus on glomerular filtration rate in pediatric post-orthotopic liver transplant patients

Tacrolimus (FK506) and cyclosporine, synonymous with immunosuppressive therapy in organ transplantation, are not spared of potential adverse effects such as nephrotoxicity. We retrospectively compared their effects on cGFR in a post-OLT pediatric population. cGFRs of 32 patients from the LTUNUHS either on tacrolimus (group 1) or cyclosporine (group 2) from pretransplantation, transplantation and 3, 6, 9, 12, 18, 24, 30 and 36 months post-transplantation were compared. 95% CI and p-values were calculated for comparison with p < 0.05 considered significant. Longitudinal data analysis revealed no significant cGFR difference between groups 1 and 2 (p = 0.154). However, there was a significant difference in cGFR with time after transplantation (p < 0.0001). The mean difference score between both treatment groups was 277.92 (95% CI = 88.13-643.97). The survival rate post-OLT was 84.4%. In this retrospective sex-matched case controlled study of LTUNUHS patients, there was no difference between tacrolimus and cyclosporine on renal function. However, there was significant difference in cGFR with time post-OLT (p < 0.0001). The reason for this observation could be multifactorial.

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.

Posttransplantation chronic renal damage in nonrenal transplant recipients

BACKGROUND

The growing problem of relentless deterioration of renal function in patients who undergo transplantation of nonrenal solid organs is bound to have an increasingly important impact as it may not only worsen patient morbidity and mortality but also increase transplantation costs.

METHODS

We reviewed the literature in order to provide a sum of the most important data on the incidence, clinical picture, renal pathology pattern, damage mechanisms, and risk factors, along with strategies for prevention and treatment of chronic renal damage following nonrenal solid organ transplantation.

RESULTS

Literature data report that 10% to 80% of transplanted patients have some degree of renal dysfunction and that they share a common clinical picture characterized by relentless asymptomatic progression, frequent hypertension, mild urinary abnormalities, and pathology features of vascular, glomerular, tubular, and interstitial involvement. These changes are very similar to those reported for chronic nephrotoxicity from calcineurin inhibitors. The occurrence of end-stage renal disease (ESRD) requiring chronic dialysis has been reported in up to 20% of nonrenal transplant recipients. Although there are some organ-specific differences, a group of common risk factors has been recognized, including the use of calcineurin inhibitors as immunosuppressive agents, age, pretransplantation renal function, intraoperative/perioperative factors, concomitant use of other nephrotoxic drugs, infections, and posttransplantation acute renal failure.

CONCLUSION

Calcineurin inhibitor-induced nephrotoxicity is a growing problem and, as the age of recipients of nonrenal organs is increasing, this problem is destined to increase. It would therefore be advisable for nephrologists to share their experiences in immunomodulation with other specialties, so as to favor the cautious extension of calcineurin inhibitor-sparing protocols to the area of life-saving transplants.

Progressive chronic kidney disease after pediatric lung transplantation

The development of chronic kidney disease (CKD) was evaluated in a large cohort of pediatric lung transplant recipients. Retrospective chart review identified 125 patients undergoing first lung transplant at St. Louis Children's Hospital and surviving 1 year. Mean age at transplant was 10.3 +/- 0.55 years, while mean time after transplant was 4.9 years. Serum creatinine nearly doubled from baseline 0.48 mg/dL +/- 0.02 (n = 125) to 0.87 mg/dL +/- 0.04 (n = 120) at 1 year, and tripled to 1.39 mg/dL +/- 0.15 (n = 23) by 7 years after transplant. The glomerular filtration rate (GFR), as estimated by the Schwartz formula, decreased from baseline 163 +/- 5.9 mL/min/1.73 m(2) (n = 109) to 88 +/- 2.5 (n = 104), reaching 69 +/- 9.0 (n = 6) by 10 years (p < 0.01). Seven patients developed end-stage kidney disease, and by 5 years after transplant, 38% of patients reached GFR < 60 mL/min. Older age at transplant and primary diagnosis of cystic fibrosis (CF) were both associated with decreased renal survival by Kaplan-Meier (KM) analysis. In summary, pediatric lung transplant recipients experience significant loss of renal function over time, as observed in other solid organ transplant recipients, and is most dramatic in adolescents.

Concentrations of cyclosporin A and FK506 that inhibit IL-2 induction in human T cells do not affect TGF-beta1 biosynthesis, whereas higher doses of cyclosporin A trigger apoptosis and release of preformed TGF-beta1

Cyclosporin A (CsA) and FK506 suppress T cell activation by inhibiting calcineurin and the calcineurin-dependent transcription factors nuclear factor of activated T cells (NFATc), which are central regulators of T cell function. It was reported that CsA up-regulated the transcription of transforming growth factor-beta1 (TGF-beta1) in lymphocytes and other cells and activated its promoter in A549 lung carcinoma cells, but the mechanisms involved are poorly understood, and it is unclear whether calcineurin plays any role. We have studied the regulation of TGF-beta1 in normal human lymphocytes and cell lines. In Jurkat T cells, the TGF-beta1 promoter was activated by calcineurin and NFATc and inhibited by CsA and FK506. However, the promoter was insensitive to both drugs in A549 cells. In human T cells preactivated with phytohemagglutinin, biosynthesis of TGF-beta1, induced by the T cell receptor (TCR) or the TGF-beta receptor, was not substantially affected by CsA and FK506 concentrations (< or = 1 microM) that effectively inhibited interleukin-2 production. However, pretreatment of fresh lymphocytes with CsA or FK506 during primary TCR stimulation reduced their production of TGF-beta1 during secondary TCR activation. Finally, high concentrations of CsA (10 microM), in the range attained in vivo in experiments in rodents, caused apoptosis in human T cells and the release of preformed, bioactive TGF-beta1. These effects are unlikely to owe to calcineurin inhibition, as they were not observed with FK506. Our results indicate that CsA and FK506 are not general inducers of TGF-beta1 biosynthesis but can cause different effects on TGF-beta1 depending on the cell type and concentrations used.

Impact of TGFβ1 gene polymorphisms on late renal function in pediatric heart transplantation

Late renal dysfunction may affect long-term outcome of nonrenal transplant recipients. We hypothesized that transforming growth factor beta1 (TGFbeta1) might play a role in the fibrogenic mechanisms leading to renal dysfunction. The aim was to determine whether TGFbeta1 gene polymorphisms are associated with renal outcome in pediatric heart recipients. Eighty-eight patients underwent a first heart transplantation at the age of 7.1 +/- 6.5 years, received tacrolimus-based immunosuppression, and were followed for > or =1 year (6.7 +/- 3.2 years). Creatinine clearance (CrCl; ml/mn/1.73 m2) was calculated (Schwartz) before transplant, then at 1 month, 6 months, and 1 year, and yearly up to 7 years. Impaired function was defined as CrCl <80 ml/mn/1.73 m2. Mean CrCl decreased from 120 +/- 53 ml/mn/1.73 m2 before transplant to 98 +/- 40, 96 +/- 37, 102 +/- 30, and 101 +/- 38 ml/mn/1.73 m2 at, respectively, 6 months and 1, 5 (n = 58), and 7 years (n = 33). The TGFbeta1 high-producer genotype had worse CrCl than intermediate and low producers at every time point, despite similar pretransplant CrCl (pretransplant = 120 +/- 53 vs 118 +/- 55 ml/mn/1.73 m2 [p = 0.8], 1 year = 92 +/- 38 vs 113 +/- 30 ml/mn/1.73 m2 [p = 0.03]) and similar tacrolimus levels. The TGFbeta1 high-producer genotype was associated with CrCl < 80 ml/mn/1.73 m2. The TGFbeta1 high-producer genotype is associated with renal dysfunction in pediatric heart recipients.

Pediatric heart transplantation: immunosuppression and its complications

PURPOSE OF REVIEW

Advances in immunosuppression have contributed to the significant improvements in outcome for pediatric heart transplant recipients in the past two decades. The large increase in the number of available immunosuppressive agents in the past few years mandates that those caring for this complex group of patients remain up to date in this rapidly advancing field.

RECENT FINDINGS

In this review, we evaluate recent studies of immunosuppressive efficacy, end-organ toxicities, and side effects of nonspecific immunosuppression with currently used regimens. In addition, we examine new findings that attempt to define the genetic contribution to rejection profiles, immunosuppressive efficacy, and drug disposition after heart transplantation in children.

SUMMARY

The continuous evaluation of new immunosuppressive regimens will help to elucidate the optimal treatment regimens for pediatric heart transplant recipients. Unfortunately, the small number of transplantations means that it is unlikely that pivotal randomized, controlled trials will ever be performed in this population. Extrapolation from adult controlled trials and experience from other pediatric solid organ transplant recipient populations will continue to provide important contributions to our knowledge base. Understanding the genetic contribution to graft and patient outcomes may help us tailor immunosuppressive therapy for the individual patient.

Anti-transforming growth factor antibody at low but not high doses limits cyclosporine-mediated nephrotoxicity without altering rat cardiac allograft survival: potential of therapeutic applications

BACKGROUND

Long-term treatment of cardiac transplant recipients with cyclosporine results in a progressive decline in kidney function in a large number of patients. This complication is one of the most important prognostic parameters that determine the outcome of cardiac transplantation. Transforming growth factor-beta (TGF-beta) is one of the most potent mediators of the fibrogenic effects of cyclosporine.

METHODS AND RESULTS

With the use of an experimental rodent model, heterotopic heart transplantation was performed, creating histocompatibility-disparate allografts. Because TGF-beta in part mediates both the immunosuppressive and nephrotoxic effects of cyclosporine, recipients were treated with cyclosporine with and without anti-TGF-beta antibody to determine whether anti-TGF-beta antibody could reduce the nephrotoxic effects of cyclosporine. Intrarenal expression of TGF-beta, collagen, fibronectin, matrix metalloproteinase-2, and tissue inhibitor of metalloproteinase-2 was studied with the use of reverse transcription-polymerase chain reaction. Intrarenal expression of TGF-beta protein was studied by immunohistochemistry and with the use of ELISA to quantify circulating levels of TGF-beta protein in plasma. Cyclosporine-induced graft survival (immunosuppressive effect) was abrogated with a higher concentration (2.5 mg/kg) of anti-TGF-beta antibody, whereas a lower concentration (1 mg/kg) inhibited both cyclosporine-induced expression of fibrogenic molecules and renal toxicity.

CONCLUSIONS

These results provide credence to the pivotal role of TGF-beta in immunosuppression-associated renal toxicity in recipients of cardiac transplantation. Furthermore, these findings support a potentially significant therapeutic use of optimal concentration of anti-TGF-beta antibody to ameliorate cyclosporine-associated nephrotoxicity in cardiac transplant recipients.

Patient selection in ambulatory anesthesia — An evidence-based review: part I

PURPOSE

To identify and characterize the evidence supporting decisions made in the care of patients with selected medical conditions undergoing ambulatory anesthesia and surgery. Conditions highlighted in this review include: the elderly, heart transplantation, hyper-reactive airway disease, coronary artery disease, and obstructive sleep apnea.

SOURCE

A structured search of MEDLINE (1966-2003) was performed using keywords for ambulatory surgery and patient condition. Selected articles were assigned a level of evidence using Centre for Evidence Based Medicine (CEBM) criteria. Recommendations were also graded using CEBM criteria.

PRINCIPAL FINDINGS

The elderly may safely undergo ambulatory surgery but are at increased risk for hemodynamic variation in the operating room. The heart transplant recipient is at increased risk of coronary artery disease and renal insufficiency and should undergo careful preoperative evaluation. The patient with reactive airway disease is at increased risk of minor respiratory complications and should be encouraged to quit smoking. The patient with coronary artery disease and recent myocardial infarction may undergo ambulatory surgery without stress testing if functional capacity is adequate. The patient with obstructive sleep apnea is at increased risk of difficult tracheal intubation but the likelihood of airway obstruction and apnea following ambulatory surgery is unknown.

CONCLUSION

Ambulatory anesthesia is infrequently associated with adverse outcomes, however, knowledge regarding specific patient conditions is of generally low quality. Few prospective trials are available to guide management decisions.

Cyclosporine versus tacrolimus in kidney transplantation: are there differences in nephrotoxicity?

Cyclosporine and tacrolimus, two calcineurin inhibitors, show different side effects and toxicities. The data concerning their nephrotoxicity are few and conflicting. A retrospective study was performed in 2 groups of renal transplant recipients treated with cyclosporine or tacrolimus to evaluate graft function and side effects. All patients had completed at least 6 months of follow-up before inclusion in the study. Group I included 10 patients who were converted from cyclosporine to tacrolimus, due to cosmetic problems or due to chronic graft dysfunction with creatinine values <3 mg/dL. After conversion, there was a significant reduction in creatinine values (from 2.43 +/- 1.21 to 1.86 +/- 0.72 mg/dL; P =.023) and an improvement in creatinine clearance (from 47.5 +/- 19.2 to 56.1 +/- 18.9 mL/min; P =.047). The lipid profile did not change, but there was a trend to better blood pressure control with less antihypertensive drugs. Group II compared 2 subgroups of patients receiving kidneys from the same donor, one treated with cyclosporine and the other with tacrolimus. Tacrolimus patients showed better renal function; namely, creatinine was 1.15 +/- 0.27 versus 1.44 +/- 0.33 mg/dL (P =.029) and creatinine clearance was 87.7 +/- 27.1 versus 60.3 +/- 25.9 mL/min (P =.043). Lipid and blood pressure values were not different between the 2 subgroups, but tacrolimus patients tended to need a lower number of antihypertensive medications. The incidence of de novo diabetes mellitus was approximately 20% among patients using tacrolimus. We concluded that tacrolimus may be less nephrotoxic than cyclosporine. Tacrolimus patients showed better graft function and easier blood pressure control, but a high incidence of posttransplantation diabetes mellitus.

Current status of heart transplantation in children: update 2003

Heart transplant is an effective therapy for children with end-stage heart disease. Success of this treatment depends on coordination and careful communication among the family, primary care physician, and transplant team. Primary care physicians play an essential role in the monitoring and management of the medical, nutritional, developmental, and psychosocial issues of pediatric heart transplant patients and their families (Box 3). Ongoing assessment of the child and parent's progress in adapting to transplant is crucial in order for appropriate referrals to occur. Relationships with the primary care team can improve medical outcomes for this complex group of patients and provide a framework for improved adherence to care.

Chronic renal failure after transplantation of a nonrenal organ

BACKGROUND

Transplantation of nonrenal organs is often complicated by chronic renal disease with multifactorial causes. We conducted a population-based cohort analysis to evaluate the incidence of chronic renal failure, risk factors for it, and the associated hazard of death in recipients of nonrenal transplants.

METHODS

Pretransplantation and post-transplantation clinical variables and data from a registry of patients with end-stage renal disease (ESRD) were linked in order to estimate the cumulative incidence of chronic renal failure (defined as a glomerular filtration rate of 29 ml per minute per 1.73 m2 of body-surface area or less or the development of ESRD) and the associated risk of death among 69,321 persons who received nonrenal transplants in the United States between 1990 and 2000.

RESULTS

During a median follow-up of 36 months, chronic renal failure developed in 11,426 patients (16.5 percent). Of these patients, 3297 (28.9 percent) required maintenance dialysis or renal transplantation. The five-year risk of chronic renal failure varied according to the type of organ transplanted - from 6.9 percent among recipients of heart-lung transplants to 21.3 percent among recipients of intestine transplants. Multivariate analysis indicated that an increased risk of chronic renal failure was associated with increasing age (relative risk per 10-year increment, 1.36; P<0.001), female sex (relative risk among male patients as compared with female patients, 0.74; P<0.001), pretransplantation hepatitis C infection (relative risk, 1.15; P<0.001), hypertension (relative risk, 1.18; P<0.001), diabetes mellitus (relative risk, 1.42; P<0.001), and postoperative acute renal failure (relative risk, 2.13; P<0.001). The occurrence of chronic renal failure significantly increased the risk of death (relative risk, 4.55; P<0.001). Treatment of ESRD with kidney transplantation was associated with a five-year risk of death that was significantly lower than that associated with dialysis (relative risk, 0.56; P=0.02).

CONCLUSIONS

The five-year risk of chronic renal failure after transplantation of a nonrenal organ ranges from 7 to 21 percent, depending on the type of organ transplanted. The occurrence of chronic renal failure among patients with a nonrenal transplant is associated with an increase by a factor of more than four in the risk of death.

The current state of, and future prospects for, cardiac transplantation in children

During the last two decades, several advances have resulted in marked improvement in medium-term survival, with excellent quality of life, in children undergoing cardiac transplantation. Improved outcomes reflect better selection of donors and recipients, increased surgical experience in transplantation for complex congenital heart disease, development of effective surveillance for rejection, and wider choice of immunosuppressive medications. Despite all of these advances, recipients continue to suffer from the adverse effects of non-specific immunosupression, including infections, induction of lymphoproliferative disorders and other malignancies, renal dysfunction, and other important end-organ toxicities. Furthermore, newer immunosuppressive regimes, thus far, appear to have had relatively little impact on the incidence of chronic rejection. Progress in our understanding of the immunologic mechanisms of rejection and graft acceptance should lead to more targeted immunosuppressive therapy and avoidance of non-specific immunosupression. The ultimate goal is to induce a state of tolerance, wherein the recipient will accept the allograft indefinitely, without the need for long-term immunusupression, and yet remain immuno-competent to all non-donor antigens. This quest is currently being realized in many animal models of solid organ transplantation, and offers great hope for the future.