Late rejection is a predictor of transplant coronary artery disease in children

Recurrent Mild Acute Rejections and Donor-specific Antibodies as Risk Factors for Cardiac Allograft Vasculopathy in a National Pediatric Heart Transplant Cohort

Background

Immune-mediated factors such as acute cellular rejections and donor-specific antibodies (DSAs) are risk factors for cardiac allograft vasculopathy (CAV). We studied a national cohort with a unified setting and thorough protocol endomyocardial biopsy (EMB) data for an association between cellular rejections, especially when mild and recurrent, and DSAs with CAV in pediatric heart transplant (HTx) patients.

Methods

This is a retrospective, national cohort study of 94 pediatric HTxs performed between 1991 and 2019 and followed until December 31, 2020. Diagnosis of CAV was based on reevaluation of angiographies. Protocol and indication EMB findings with other patient data were collected from medical records. Associations between nonimmune and immune-mediated factors and CAV were analyzed with univariable and multivariable Cox regression analyses.

Results

Angiographies performed on 76 patients revealed CAV in 23 patients (30%). Altogether 1138 EMBs (92% protocol biopsies) were performed on 78 patients (83%). During the first posttransplant year, grade 1 rejection (G1R) appeared in 45 patients (58%), and recurrent (≥2) G1R findings in 14 patients (18%). Pretransplant DSAs occurred in 13 patients (17%) and posttransplant DSAs in 37 patients (39%). In univariable analysis, pretransplant DSAs, appearance and recurrence of G1R findings, and total rejection score during the first posttransplant year, as well as recurrent G1R during follow-up, were all associated with CAV. In multivariable analysis, pretransplant DSAs and recurrent G1R during the first posttransplant year were found to be associated with CAV.

Conclusions

Our results indicate that pretransplant DSA and recurrent G1R findings, especially during the first posttransplant year, are associated with CAV after pediatric HTx.

Practice variation in the diagnosis of acute rejection among pediatric heart transplant centers: An analysis of the pediatric heart transplant society (PHTS) registry

BACKGROUND

Freedom from rejection in pediatric heart transplant recipients is highly variable across centers. This study aimed to assess the center variation in methods used to diagnose rejection in the first-year post-transplant and determine the impact of this variation on patient outcomes.

METHODS

The PHTS registry was queried for all rejection episodes in the first-year post-transplant (2010-2019). The primary method for rejection diagnosis was determined for each event as surveillance biopsy, echo diagnosis, or clinical. The percentage of first-year rejection events diagnosed by surveillance biopsy was used to approximate the surveillance strategy across centers. Methods of rejection diagnosis were described and patient outcomes were assessed based on surveillance biopsy utilization among centers.

RESULTS

A total of 3985 patients from 56 centers were included. Of this group, 873 (22%) developed rejection within the first-year post-transplant. Surveillance biopsy was the most common method of rejection diagnosis (71.7%), but practices were highly variable across centers. The majority (73.6%) of first rejection events occurred within 3-months of transplantation. Diagnosis modality in the first-year was not independently associated with freedom from rejection, freedom from rejection with hemodynamic compromise, or overall graft survival.

CONCLUSIONS

Rejection in the first-year after pediatric heart transplant occurs in 22% of patients and most commonly in the first 3 months post-transplant. Significant variation exists across centers in the methods used to diagnose rejection in pediatric heart transplant recipients, however, these variable strategies are not independently associated with freedom from rejection, rejection with hemodynamic compromise, or overall graft survival.

Variation in the use of surveillance endomyocardial biopsy among pediatric heart transplant centers over time

EMB is widely utilized for graft surveillance after HTx; however, there is significant variation in the frequency of surveillance EMB use during the first year post-HTx. The aim of this study was to assess changes in the utilization of surveillance EMB over time among member institutions of PHTS. A survey of PHTS centers assessing the frequency of surveillance EMB use during the first year post-HTx was conducted in 2006. The same survey was repeated in 2014 to assess changes in practice over time. The number of EMB in infants ranged from 0 to 9 and in adolescents 0 to 16. The number of EMB decreased or remained unchanged in the majority of centers. Fewer EMB are performed in infants compared to adolescents and this practice did not change over time. There was a significant decrease in surveillance EMB use in adolescents (p = 0.012). International centers perform significantly fewer EMB in adolescents when compared to centers within the United States (p = 0.006). There continues to be significant variation in the utilization of surveillance EMB, with a shift toward less reliance on EMB for adolescents in the current era. Further research is necessary to determine the optimal frequency of invasive monitoring that reduces costs without compromising outcomes.

Mechanical circulatory assist as a bridge to heart retransplantation in adolescents

We report our experience with an adolescent patient who required complex management leading to retransplantation for coronary allograft vasculopathy and also review the role of ventricular assist device support in patients with this clinical entity.

State of the art in paediatric heart transplantation: the Berlin experience

Enormous progress has been made in paediatric heart transplantation since the first unsuccessful effort by Kantrowitz in 1967. Early reports of children undergoing heart transplantation showed alarmingly high perioperative mortality rates of 25-60%, with the diagnosis of congenital heart disease (CHD) representing a particularly high-risk subset compared with cardiomyopathy. Many of these early failures were related to poor patient selection, suboptimal immunosuppression and technical problems. We learned a great deal from these earlier difficulties. Presently, with more refined techniques, better-defined patient selection criteria, excellent graft rejection monitoring and optimal immunosuppression, the ISHLT 2011 registry reported a 10-year survival rate of 60% for patients transplanted for end-stage CHD and >70% for those transplanted for cardiomyopathy. The technical dilemmas in complex CHD were overcome by surgical ingenuity and creativity, innovative solutions and careful surgical planning, adapting the complex recipient anatomy to the normal donor anatomy. The miniaturized Berlin Heart pulsatile ventricular assist devices in children as a bridge to transplantation have revolutionized treatment and become a significant contribution in heart-failure therapy. The intramyocardial electrogram and echocardiographic strain rate imaging have been employed as non-invasive techniques of rejection monitoring. Immunosuppressive drugs have a major impact on the development and progression of cardiac allograft vasculopathy, the main cause of cardiac allograft loss and a leading cause of mortality after the first year post-transplantation. The questions of whether a transplanted heart in a newborn grows to adult size along with the child and whether the dimensional cardiac growth allows adequate function over time have been largely answered in our previous investigations. As more transplanted children reach adulthood, concerns about their life expectancy when they have reached 10 years of life post-transplant are raised, particularly with respect to establishing partnerships and families, their ability to earn a living and the fulfilment of personal life perspectives. Some heart-transplanted patients require retransplantation to remain alive. The disparity between the demand for and supply of donor hearts makes retransplantation an ethical issue. We 'do not refuse' any patient who needs retransplantation. Mechanical circulatory support devices for long-term use are now largely available to accommodate such cases.

Very late heart transplant rejection is associated with microvascular injury, complement deposition and progression to cardiac allograft vasculopathy

In heart transplants, the significance of very late rejection (after 7 years post-transplant, VLR) detected by routine endomyocardial biopsies (EMB) remains uncertain. Here, we assessed the prevalence, histopathological and immunological phenotype, and outcome of VLR in clinically stable patients. Between 1985 and 2009, 10 662 protocol EMB were performed at our institution in 398 consecutive heart transplants recipients. Among the 196 patients with >7-year follow-up, 20 (10.2%) presented subclinical ≥3A/2R-ISHLT rejection. The VLR group was compared to a matched control group of patients without rejection. All biopsies were stained for C4d/C3d/CD68 with sera screened for the presence of donor-specific antibodies (DSAs). In addition to cellular infiltrates with myocyte damage, 60% of VLR patients had evidence of intravascular macrophages. C4d and/or C3d-capillary deposition was found in 55% VLR EMB. All cases of VLR associated with microcirculation injury had DSAs (mean DSA(max) -MFI = 1751 ± 583). This entity was absent from the control group (p < 0.0001). Finally, after a similar follow-up postreference EMB of 6.4 ± 1 years, the mean of CAV grade was 0.76 ± 0.18 in the control group compared to 2.06 ± 0.26 in the VLR group respectively, p = 0.001). There was no difference in patient survival between study and control groups. In conclusion, VLR is frequently associated with complement-cascade activation, microvascular injury and DSA, suggesting an antibody-mediated process. VLR is associated with a dramatic progression to severe CAV in long-term follow-up.

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.

Outcome of acute graft rejection associated with hemodynamic compromise in pediatric heart transplant recipients

We sought to analyze the outcome of hemodynamically significant acute graft rejection in pediatric heart transplant recipients from a single-center experience. Acute graft rejection remains a major cause of morbidity and mortality for patients who undergo orthotopic heart transplantation and has been associated with the severity of the rejection episode. A retrospective review of all children experiencing a hemodynamically significant rejection episode after orthotopic heart transplantation was performed. Fifty-three patients with 54 grafts had 70 rejection episodes requiring intravenous inotropic support. Forty-one percent of these patients required high-dose inotropic support, with the remaining 59% of patients requiring less inotropic support. Overall graft survival to hospital discharge was 41% for patients in the high-dose group compared to 94% in the low-dose group. Six-month graft survival in patients who required high-dose inotropes remained at 41% compared to 44% in the low-dose group. Hemodynamically significant acute graft rejection in pediatric heart transplant recipients is a devastating problem with poor short- and long-term outcomes. Survival to hospital discharge is dismal in patients who require high-dose inotropic support. In contrast, survival to discharge is quite good in patients who require only low-dose inotropic support; however, six-month graft survival in this group is low secondary to a high incidence of graft failure related to worsening or aggressive transplant coronary artery disease.

International Society for Heart and Lung Transplantation working formulation of a standardized nomenclature for cardiac allograft vasculopathy-2010

The development of cardiac allograft vasculopathy remains the Achilles heel of cardiac transplantation. Unfortunately, the definitions of cardiac allograft vasculopathy are diverse, and there are no uniform international standards for the nomenclature of this entity. This consensus document, commissioned by the International Society of Heart and Lung Transplantation Board, is based on best evidence and clinical consensus derived from critical analysis of available information pertaining to angiography, intravascular ultrasound imaging, microvascular function, cardiac allograft histology, circulating immune markers, non-invasive imaging tests, and gene-based and protein-based biomarkers. This document represents a working formulation for an international nomenclature of cardiac allograft vasculopathy, similar to the development of the system for adjudication of cardiac allograft rejection by histology.

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.

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.

Genetic polymorphisms impact the risk of acute rejection in pediatric heart transplantation: a multi-institutional study

OBJECTIVE

The objective of this study was to determine the association between the genetic polymorphisms of proinflammatory and regulatory cytokines and long-term rates of repeat and late acute rejection episodes in pediatric heart transplant (PHTx) recipients.

METHODS

Three hundred twenty-three PHTx recipients: 205 White non-Hispanic, 43 Black non-Hispanic, and 75 Hispanic were analyzed for time to first repeat and late acute rejection episodes by race, age at transplantation, and gene polymorphism (interleukin [IL]-6, -174 G/C, IL-10, -1082 G/A, -819 C/T, 592 C/A; vascular endothelial growth factor (VEGF) -2578 C/A, -460 C/T, +405 C/G; tumor necrosis factor alpha (TNF-alpha)-308 G/A).

RESULTS

Recipient black race and older age at transplant were risk factors for both repeat and late rejections, though black race was more significantly related to late rejection (P=0.006). Individually, TNF-alpha high, IL-6 high, VEGF high, and IL-10 low phenotypes did not impact the risk of repeat or late rejection. However, the combination VEGF high/IL-6 high and IL-10 low was associated with increased estimated risk of late rejection (P=0.0004) and only marginally with repeat rejection (P=0.051). In a multivariate analysis, adjusting for age and race, VEGF high/IL-6 high and IL-10 low still remained an independent risk factor for late acute rejection (RR=1.91, P<0.001).

CONCLUSION

This is the largest multicenter study to document the impact of genetic polymorphism combinations on PHTx recipients' outcome. The high proinflammatory (VEGF high/IL-6 high) and lower regulatory (IL-10 low) cytokine gene polymorphism profile exhibited increased risk for late rejection, irrespective of age and race/ethnicity.

Identification of coronary artery disease in the pediatric cardiac transplant patient

Little data exist to identify pediatric patients who have developed transplant coronary artery vasculopathy (CAV). Transplant patients do not exhibit the usual signs of coronary disease, making diagnosis more difficult. The aim of this study is to assess the use of myocardial perfusion imaging to identify CAV in transplant patients and to derive an incidence of occurrence. We studied pediatric cardiac transplant recipients who have undergone myocardial perfusion imaging on a routine basis. All patients from September 1999 through November 2004 with nuclear perfusion scans were included. Twenty patients age 7-24 years (mean: 12.7), 11 male and 9 female, were studied by SPECT technetium 99M tetrofosmin imaging. Sixteen of the 20 patients were studied based on a newly instituted protocol for surveillance. Transplant was 1-14 years (mean: 7.9) earlier. Patients were also studied by stress echocardiography. Six of 20 patients (30%) had a positive perfusion scan. Ages ranged from 8 to 18 years (mean: 12). Time from transplant to positive scans ranged from 1 to 9 years (mean: 5.6). One patient showed the same perfusion defect as 2 years earlier. Five patients with positive nuclear perfusion scans showed the abnormality on the initial study; one had a previous negative study 6 months earlier. Four patients who demonstrated ischemia with exercise showed resolution at rest; the other two had no resting study. Five of these six patients with abnormal perfusion scans had negative stress echocardiograms. Only one patient identified with coronary involvement reported symptoms (exertional dyspnea). Hypertension and rejection episodes were similar in all patients and in those with positive nuclear scans. Of the six patients with positive nuclear perfusion scans, two demonstrated coronary disease at cardiac catheterization. Two patients with coronary disease at catheterization had normal nuclear perfusion scans; one of two had a normal stress echo. When three imaging modalities were used, the incidence of CAV was 30%. Symptoms in pediatric patients with CAV are seldom reported. Unfortunately, coronary arteriopathy occurs frequently and might be found as early as 1 year posttransplant. Six of 20 patients had abnormal perfusion; only 1 had any other noninvasive marker. Importantly, not all patients with CAV were identified by perfusion imaging, stress echocardiography, or coronary injection alone. Therefore, transplant patients need continued evaluation by multiple modalities for detection of developing coronary lesions.

Cardiovascular risk reduction in high-risk pediatric patients: a scientific statement from the American Heart Association Expert Panel on Population and Prevention Science; the Councils on Cardiovascular Disease in the Young, Epidemiology and Prevention, Nutrition, Physical Activity and Metabolism, High Blood Pressure Research, Cardiovascular Nursing, and the Kidney in Heart Disease; and the Interdisciplinary Working Group on Quality of Care and Outcomes Research

Although for most children the process of atherosclerosis is subclinical, dramatically accelerated atherosclerosis occurs in some pediatric disease states, with clinical coronary events occurring in childhood and very early adult life. As with most scientific statements about children and the future risk for cardiovascular disease, there are no randomized trials documenting the effects of risk reduction on hard clinical outcomes. A growing body of literature, however, identifies the importance of premature cardiovascular disease in the course of certain pediatric diagnoses and addresses the response to risk factor reduction. For this scientific statement, a panel of experts reviewed what is known about very premature cardiovascular disease in 8 high-risk pediatric diagnoses and, from the science base, developed practical recommendations for management of cardiovascular risk.

Cardiovascular Risk Reduction in High-Risk Pediatric Patients

Although for most children the process of atherosclerosis is subclinical, dramatically accelerated atherosclerosis occurs in some pediatric disease states, with clinical coronary events occurring in childhood and very early adult life. As with most scientific statements about children and the future risk for cardiovascular disease, there are no randomized trials documenting the effects of risk reduction on hard clinical outcomes. A growing body of literature, however, identifies the importance of premature cardiovascular disease in the course of certain pediatric diagnoses and addresses the response to risk factor reduction. For this scientific statement, a panel of experts reviewed what is known about very premature cardiovascular disease in 8 high-risk pediatric diagnoses and, from the science base, developed practical recommendations for management of cardiovascular risk.

Restrictive hemodynamics are present at the time of diagnosis of allograft coronary artery disease in children

Clinical recognition of allograft coronary artery disease (ACAD) is challenging. We examined whether right heart hemodynamics can aid its diagnosis in pediatric recipients. We retrospective analyzed hemodynamic data of recipients with ACAD versus age and date-of-transplant matched controls. From 1982-2001, 18 cases fulfilled study entry criteria. Median age at transplant was 12 years for subjects and 8 years for controls. Median time to diagnosis of ACAD was 65 months (14.5-124 months) and 67 months (16-140 months) to arteriography for controls. The median right ventricular end-diastolic pressure (RVEDP) at diagnosis was 11.0 vs. 6.0 mmHg for controls (p = 0.003). Pulmonary capillary wedge pressure (PCWP) at diagnosis was 14.0 vs. 8.0 mmHg for controls (p = 0.001). When subdivided by severity of ACAD, the difference was greater in the moderate/severe group. Compared to the previous catheterization (median interval 10 months for subjects, 12.0 for controls ), there was an increase of 4.0 mmHg in RVEDP in ACAD subjects (n = 13, p = .003) versus 0 mmHg in controls (p = 0.042), and an increase in PCWP of 5.5 in subjects (p = .002) versus 0 mmHg in controls (p = 0.066). The presence of elevated filling pressures plus an interim increase should alert to the presence of ACAD and help guide further investigation.

Cardiac allograft vasculopathy in pediatric heart transplant recipients

Metabolic parameters for coronary allograft vasculopathy (CAV) have not been well defined in children. CAV (by angiography or autopsy) was studied in 337 heart recipients on a cyclosporine-based steroid-sparing regimen. Freedom from CAV for all was 79% at 10 years. Fifty-nine patients (18%) developed CAV at a mean of 6.5 +/- 3 years post-transplant. First year rejections were significantly higher in CAV, mean 2.3 vs. 1.4, P = 0.003, odds ratio (OR) 1.8. Rejection with hemodynamic compromise beyond 1 year post-transplant was associated with CAV, P < 0.001, OR 8.4. There was no significant correlation among human leukocyte antigen DR (HLA DR) mismatch, pacemaker use or homocysteine levels and the development of CAV. Maximum cholesterol and low density lipoprotein (LDL) levels were not significantly different. Neither diabetes nor hypertension was significant predictors of CAV on multivariate logistic regression analysis. In conclusion, frequent and severe rejection episodes may predict pediatric CAV. Neither glucose intolerance nor lipid abnormalities appeared to alter risk for CAV in this population.

Does duration of donor brain injury affect outcome after orthotopic pediatric heart transplantation?

OBJECTIVE

We tested the hypothesis that duration of donor brain injury and death would have an adverse effect on recipient rejection and mortality in pediatric heart transplantation.

METHODS

Ninety-three cardiac transplants were performed at our center from July 1, 1997, through June 30, 2003. The primary study end points were the number of rejection episodes and the time to first rejection. Secondary outcomes were early and late mortality.

RESULTS

Among 88 recipients of 93 cardiac allografts, 5 (6%) and 1 (1%) received second and third allografts, respectively. Overall patient mortality (3 early and 2 late) was 6% (5/88), and overall graft loss was 6% (6/93). Median time from donor brain injury to declaration of brain death (brain injury interval), time from brain death to donor cardiectomy (brain death interval), and graft ischemia time were 38, 24, and 3.3 hours, respectively. Cox regression analysis (adjusting for United Network for Organ Sharing status, ventilator dependence, extracorporeal membrane oxygenation and ventricular-assist device status, diagnosis of congenital heart disease, sex and cytomegalovirus mismatches, and type of immunosuppression) demonstrated that recipients of donor hearts with relatively long periods from brain injury to death declaration or from death to organ removal had significantly improved rejection-free survival (hazard ratios 0.3, P = .01, and 0.5, P = .05, for brain injury and brain death times, respectively). Prolonged donor heart ischemia did not impact rejection rate. Increasing brain injury interval, brain death interval, and graft ischemia time had no significant effect on mortality.

CONCLUSION

Longer brain injury and death intervals correlated with improved freedom from rejection but had no effect on mortality.

Pravastatin therapy is associated with reduction in coronary allograft vasculopathy in pediatric heart transplantation

BACKGROUND

Hydroxymethylglutaryl CoA reductase inhibitors (statins) have been demonstrated to reduce the risk of developing coronary allograft vasculopathy (CAV) following heart transplantation in adults and are used routinely in many centers. CAV and lipid abnormalities have been reported to be less prevalent in pediatric heart transplant recipients. It is not known whether statins reduce the risk of CAV in this population

METHODS

A retrospective review was performed to analyze the risk factors for developing CAV following pediatric heart transplantation with particular attention to the impact of pravastatin therapy. The study population was comprised of 129 pediatric patients who underwent 142 heart transplants at our institution from 1988 to 2003. The outcome variable was freedom from CAV, CAV being determined by coronary angiography or autopsy.

RESULTS

CAV was identified in 25 recipients at a median of 3.7 years after transplantation. There were 331 patient-years of pravastatin therapy. Pravastatin therapy resulted in a reduction in total cholesterol levels, 162 +/- 29 to 137 +/- 20 mg/dl, p = 0.01. In multivariate analysis the use of pravastatin was associated with a lower incidence of CAV (p = 0.03), whereas an increased frequency of late rejection (p = 0.003) and earlier year of transplantation (p = 0.04) were associated with increased risk of CAV.

CONCLUSIONS

The routine use of pravastatin was associated with a lower risk following pediatric heart transplantation. Further studies into the relationship between lipid abnormalities, inflammation and rejection, and the development of CAV in children are warranted.

Epicardial and microvascular graft vessel disease in children

AIM

Graft vessel disease (GVD) is one of the main limiting factors to long-term survival after adult heart transplantation (HTx). The incidence of epicardial and microvascular GVD in paediatric patients was studied.

METHODS

A total of 137 coronary angiographies from 130 paediatric HTx and heart and lung transplant (HLTx) patients (70 male, 60 female, aged 0-18 y) were evaluated according to the Stanford classification and its supplements (minor vessel alterations). In H&E stainings from right ventricular endomyocardial biopsies (EMB = 397), light microscopic diagnosis of acute cellular rejection (ISHLT classification) and vascular reaction (morphology of endothelial cells and vessel walls) was performed.

RESULTS

Moderate rejection was present in 32.8% and severe rejection in 13.3% of EMB. Microvascular EC swelling was found in 33.5% and vessel wall thickening in 53.8% of EMB. The results of the coronary angiographic investigations were: Stanford lesions = 61.2%, peripheral obliterations = 52.5%, diameter fluctuations = 86.3%, pathologic tapering = 64.0%, calcifications = 10.8%. Long-term survivors (> or =5 y) showed macrovascular alterations in 78% of cases and microvascular alterations in 67% of cases.

CONCLUSION

The development of micro- and macrovascular GVD is one of the predominant complications in long-term survivors after paediatric HTx and HLTx.

Cardiac retransplantation in children

BACKGROUND

Experience with pediatric cardiac retransplantation is limited. Outcomes should be inspected to insure proper use of donor hearts.

METHODS

Of 152 pediatric heart transplantations, we performed 20 retransplants in 17 children (3 had a second retransplant). The retransplant children were older than the primary transplant children (11.1 +/- 4.4 years versus 7.1 +/- 6.0 years; p = 0.005). Excluding 1 early retransplant, the interval from primary transplant to retransplant was 5.5 +/- 3.3 years (range, 1.1 to 11.1). The retransplant patients were clinically more ill than the primary transplant patients (United Network for Organ Sharing status I, 75% versus 63%; mechanical circulatory support or dialysis, 20% versus 3.8%).

RESULTS

Donor ischemia time (188 versus 165 minutes) and cardiopulmonary bypass time (127 versus 127 minutes) were not significantly different for the retransplant patients. Excluding 1 retransplant patient who required a tracheostomy, days on the ventilator (2.7 versus 2.7), days on inotropic support (3.0 versus 3.2), intensive care unit days (7.2 versus 6.7), and hospital days (15.9 versus 13.8) were similar in the retransplant group. Freedom from rejection at 90 days and 1 year was not different in the retransplant patients. Actuarial patient survival in the patients undergoing first retransplant was similar to the primary transplant patients at 30 days (95% versus 94.7%), 1 year (94.1% versus 80.7%), and 3 years (78.4% versus 73.1%). Two of 3 children receiving a third transplant died within 1 year of redo retransplantation.

CONCLUSIONS

Cardiac retransplantation can be performed in children with results comparable with those for primary transplantation despite increased clinical acuity. These early results suggest that cardiac retransplantation in children is a reasonable therapeutic option. Children with repeat retransplantation do not fare as well.

Long-term follow-up after staged reconstruction or transplantation for patients with functionally univentricular heart

As recently as 35 years ago, children born with a functionally single ventricle were destined to a lifetime of multiple palliative operations, and disrupted growth and development. Physical signs of their cardiac disease were evidenced by chronic hypoxemia, polycythemia, clubbing, small stature, and severely reduced exercise ability. A normal lifestyle, with typical landmarks such as uninterrupted adolescence and potential childbearing, was unlikely. The successful application of right heart bypass by Fontan and Kreutzer in the early 1970s heralded an era of multiple medical and surgical breakthroughs that have systematically improved the quality of life and long-term outlook for these children.

Echocardiographic evaluation before and after cardiac transplantation

Transplantation of the heart remains a viable option not only as primary treatment for hypoplastic left heart syndrome, but also for end-stage problems after the Norwood sequence of palliations. In this review, I discuss the pre-operative, intra-operative, and post-operative echocardiographic evaluation of these patients, with special emphasis on hemodynamic and functional assessment as well as surveillance for rejection and coronary arterial disease.

Coronary artery vasculopathy in pediatric cardiac transplant patients: the therapeutic potential of immunomodulators

The single largest cause of late graft loss in pediatric cardiac transplantation is transplant coronary artery vasculopathy (CAV). The mechanism of CAV remains unknown; it appears to have both immune and non-immune causes. The final common pathway of these mechanisms is endothelial activation, a prothrombotic environment, and endothelial damage with subsequent diffuse intimal proliferation. The disease process has largely been thought to be progressive and unresponsive to treatment. Re-transplantation has been advocated as the only definitive treatment. The appropriate management is largely unknown; intervention or surgical management has had limited utility, while medical management appears to have the most promise. Improvement in outcome can be achieved by optimizing non-immune factors and aggressive management of the immune mechanisms. Long-term survival of transplant patients after diagnosis with CAV is now being reported.

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.

A comparison of intravascular ultrasound with coronary angiography for evaluation of transplant coronary disease in pediatric heart transplant recipients

BACKGROUND

The purpose of this study was to assess the sensitivity of coronary angiography versus intravascular ultrasound for detecting significant transplant coronary artery disease in children. We also examined associations between potential risk factors for transplant coronary artery disease and intravascular ultrasound findings, and evaluated the safety of intravascular ultrasound.

METHODS

All pediatric heart transplant patients who had intravascular ultrasound following routine coronary angiography were included. Transplant coronary artery disease was quantified by assigning Stanford classes and calculating intimal indices for intravascular ultrasound images. These findings were compared with qualitative coronary angiography findings. Risk factors for transplant coronary artery disease, cardiac events and complications were recorded.

RESULTS

Sixteen patients had 27 intravascular ultrasound procedures during the study period. All patients had evidence of transplant coronary artery disease at their latest intravascular ultrasound study. Of the patients whose most severely afflicted coronary artery underwent both imaging modalities at the latest study, 50% had significant transplant coronary artery disease (Stanford Class >/=II) by intravascular ultrasound and normal coronary angiography. A higher mean first-year biopsy score may be associated with significant transplant coronary artery disease by intravascular ultrasound, but a large number of patients will be required to determine this with statistical certainty. One major complication occurred early in the experience.

CONCLUSIONS

In children, intravascular ultrasound is more sensitive for detecting significant transplant coronary artery disease than coronary angiography, but may add cost, time and potential morbidity to screening protocols. Prospective, multicenter studies are needed to best utilize intravascular ultrasound in this patient population.