Richard Chinnock

Association of Viral Genome with Graft Loss in Children after Cardiac Transplantation

BACKGROUND The survival of recipients of cardiac allografts is limited by rejection, lymphoproliferative disease, and coronary vasculopathy. The purpose of this study in children who had received heart transplants was to evaluate the cardiac allografts for myocardial viral infections and to determine whether the presence of viral genome in the myocardium correlates with rejection, coronary vasculopathy, or graft loss. METHODS We enrolled heart-transplant recipients 1 day to 18 years old who were undergoing evaluation for possible rejection and coronary vasculopathy. Endomyocardial-biopsy specimens were evaluated for evidence of rejection with the use of standard criteria and were analyzed for the presence of virus by the polymerase chain reaction (PCR). RESULTS PCR analyses were performed on 553 consecutive biopsy samples from 149 transplant recipients. Viral genome was amplified from 48 samples (8.7 percent) from 34 patients (23 percent); adenovirus was found in 30 samples, enterovirus in 9 samples, parvovirus in 5 samples, cytomegalovirus in 2 samples, herpes simplex virus in 1 sample, and Epstein-Barr virus in 1 sample. In 29 of the 34 patients with positive results on PCR (85 percent), an adverse cardiac event occurred within three months after the positive biopsy, and 9 of the 34 patients had graft loss due to coronary vasculopathy, chronic graft failure, or acute rejection. In 39 of the 115 patients with negative results on PCR (34 percent), an adverse cardiac event occurred within three months of the negative PCR finding; graft loss did not occur in any of the patients in this group. The odds of graft loss were 6.5 times as great among those with positive results on PCR (P=0.006). The detection of adenovirus was associated with considerably reduced graft survival (P=0.002). CONCLUSIONS Identification of viral genome, particularly adenovirus, in the myocardium of pediatric transplant recipients is predictive of adverse clinical events, including coronary vasculopathy and graft loss.

Association of Parvovirus B19 Genome in Children With Myocarditis and Cardiac Allograft Rejection Diagnosis Using the Polymerase Chain Reaction

BACKGROUND Inflammatory diseases of the heart, including myocarditis and cardiac transplant rejection, are important causes of morbidity and mortality in children. Although viral infection may be suspected in either of these clinical conditions, the definitive etiology is often difficult to ascertain. Furthermore, the histology is identical for both disorders. Coxsackievirus has long been considered the most common cause of viral myocarditis; however, we previously demonstrated by polymerase chain reaction (PCR) analysis that many different, and sometimes unexpected, viruses may be responsible for myocarditis and cardiac rejection. In this study, we describe the association of parvovirus genome identified through PCR analysis of cardiac tissue in the clinical setting of myocarditis and cardiac allograft rejection. METHODS AND RESULTS Myocardial tissue from endomyocardial biopsy, explant, or autopsy was analyzed for parvovirus B19 using primers designed to amplify a 699-base pair PCR product from the VP1 gene region. Samples tested included those obtained from patients with suspected myocarditis (n=360) or transplant rejection (n=200) or control subjects (n=250). Parvoviral genome was identified through PCR in 9 patients (3 myocarditis; 6 transplant) and no control patients. Of the 3 patients with myocarditis, 1 presented with cardiac arrest leading to death, 1 developed dilated cardiomyopathy, and the other gradually improved. Four of the 6 transplant patients had evidence of significant rejection on the basis of endomyocardial biopsy histology. All transplant patients survived the infection. CONCLUSIONS Parvovirus is associated with myocarditis in a small percentage of children and may be a potential contributor to cardiac transplant rejection. PCR may provide a rapid and sensitive method of diagnosis.

Transplantation as a primary treatment for hypoplastic left heart syndrome: intermediate-term results.

BACKGROUND Hypoplastic left heart syndrome is a lethal malformation. For the last 10 years, orthotopic cardiac transplantation has been our preferred treatment for infants with hypoplastic left heart syndrome. METHODS One hundred seventy-six infants with hypoplastic left heart syndrome were entered into a cardiac transplant protocol between November 1985 and November 1995. Interventional procedures to stent the ductus arteriosus or enlarge the interatrial communication were performed in 8 and 35 patients, respectively. Thirty-four patients (19%) died during the waiting period, and 142 infants underwent cardiac transplantation. Age at cardiac transplantation ranged from 1.5 hours to 6 months (median, 29 days). The majority of grafts were oversized, and the median graft ischemic time was 273 minutes (range, 60 to 576 minutes). The implantation procedure used a period of hypothermic circulatory arrest ranging from 23 to 110 minutes (median, 53 minutes). Repair of other significant defects included interrupted aortic arch and total or partial anomalous pulmonary venous connection. RESULTS There were 13 early and 22 late deaths. Patient actuarial survival at 1 month and at 1, 5 and 7 years was 91%, 84%, 76%, and 70% respectively. Half of the late deaths were due to rejection. Severe graft vasculopathy was confirmed in 8 patients. Retransplantation was performed in 5 patients for graft vasculopathy 4 and rejection 1. Lymphoblastic leukemia developed in 1 patient 3 years after cardiac transplantation. CONCLUSIONS Cardiac transplantation can be performed in infants with hypoplastic left heart syndrome with good operative and intermediate-term results. Improved survival can be achieved with increased donor availability, better management of rejection, and control of graft vasculopathy.

Relationship of Surgical Approach to Neurodevelopmental Outcomes in Hypoplastic Left Heart Syndrome

OBJECTIVE. Two strategies for surgical management are used for infants with hypoplastic left heart syndrome (HLHS), primary heart transplantation and the Norwood procedure. We sought to determine how these 2 surgical approaches influence neurodevelopmental outcomes at school age. METHODS. A multicenter, cross-sectional study of neurodevelopmental outcomes among school-aged children (>8 years of age) with HLHS was undertaken between July 2003 and September 2004. Four centers enrolled 48 subjects, of whom 47 completed neuropsychologic testing. Twenty-six subjects (55%) had undergone the Norwood procedure and 21 (45%) had undergone transplantation, with an intention-to-treat analysis. The mean age at testing was 12.4 ± 2.5 years. Evaluations included the Wechsler Abbreviated Scale of Intelligence, Clinical Evaluation of Language Fundamentals, Wechsler Individual Achievement Test, and Beery-Buktenica Developmental Test of Visual-Motor Integration. RESULTS. The mean neurocognitive test results were significantly below population normative values. The mean full-scale IQ for the entire cohort was 86 ± 14. In a multivariate model, there was no association of surgical strategy with any measure of developmental outcome. A longer hospital stay, however, was associated significantly with lower verbal, performance, and full-scale IQ scores. Aortic valve atresia was associated with lower math achievement test scores. CONCLUSIONS. Neurodevelopmental deficits are prevalent among school-aged children with HLHS, regardless of surgical approach. Complications that result in prolonged hospitalization at the time of the initial operation are associated with neurodevelopmental status at school age.

Survival and risk factors for death after cardiac transplantation in infants: A multi-institutional study

BACKGROUND Despite the increasing application of cardiac transplantation in infants, reported survival rates vary, and risk factors for death are poorly understood. METHODS AND RESULTS To examine early survival and risk factors for death in infants (< 1 year of age) undergoing cardiac transplantation, 141 infants (36 < 1 months of age) underwent primary cardiac transplantation between January 1, 1993, and January 1, 1995, at 23 centers in the Pediatric Heart Transplant Study (PHTS). Diagnoses were hypoplastic left heart syndrome (66%), other congenital heart disease (17%), cardiomyopathy (14%), and other (3%). Actuarial survival after cardiac transplantation was 84% at 1 month, 70% at 1 year, and 69% at 2 years, with the greatest hazard for death within the first 3 months. The principal cause of death was early graft failure in 20 patients (52% of deaths), infection in 10 (26% of deaths), and rejection in 4 (10%). On the basis of multivariate analysis, risk factors for early mortality were history of previous sternotomy (P = .0003), nonidentical blood type donor (P = .01), recipient non-blood group A (P = .02), and donor cause of death other than closed head trauma (P = .04). Diagnosis at listing, waiting time (mean, 1.3 months), graft ischemic time (mean, 228 minutes; range, 68 to 479 minutes), and recipient ventilatory or inotropic support at listing were not predictive for mortality after transplant. CONCLUSIONS The higher mortality rate observed with infant heart transplantation is due to a higher mortality within the first month after transplantation as a result of early graft failure. Strategies to improve donor heart function at implantation would have the greatest impact on survival after infant cardiac transplantation.

Survival analysis and risk factors for mortality in transplantation and staged surgery for hypoplastic left heart syndrome.

OBJECTIVES We compared survival in treatment strategies and determined risk factors for one-year mortality for hypoplastic left heart syndrome (HLHS) using intention-to-treat analysis. BACKGROUND Staged revision of the native heart and transplantation as treatments for HLHS have been compared in treatment-received analyses, which can bias results. METHODS Data on 231 infants with HLHS, born between 1989 and 1994 and intended for surgery, were collected from four pediatric cardiac surgical centers. Status at last contact for survival analysis and mortality at one year for risk factor analysis were the outcome measures. RESULTS Survival curves showed improved survival for patients intended for transplantation over patients intended for staged surgery. One-year survival was 61% for transplantation and 42% for staged surgery (p < 0.01); five-year survival was 55% and 38%, respectively (p < 0.01). Survival curves adjusted for preoperative differences were also significantly different (p < 0.001). Waiting-list mortality accounted for 63% of first-year deaths in the transplantation group. Mortality with stage 1 surgery accounted for 86% of that strategys first-year mortality. Birth weight <3 kg (odds ratio [OR] 2.4), highest creatinine > or =2 mg/dL (OR 4.7), restrictive atrial septal defect (OR 2.7) and, in staged surgery, atresia of one (OR 4.2) or both (OR 11.0) left-sided valves produced a higher risk for one-year mortality. CONCLUSIONS Transplantation produced significantly higher survival at all ages up to seven years. Patients with atresia of one or both valves do poorly in staged surgery and have significantly higher survival with transplantation. This information may be useful in directing patients to the better strategy for them.

Dynamic Production of Hypoxia‐Inducible Factor‐1α in Early Transplanted Islets

More than half of transplanted β‐cells undergo apoptotic cell death triggered by nonimmunological factors within a few days after transplantation. To investigate the dynamic hypoxic responses in early transplanted islets, syngeneic islets were transplanted under the kidney capsule of balb/c mice. Hypoxia‐inducible factor‐1α (HIF‐1α) was strongly expressed at post‐transplant day (POD) 1, increased on POD 3, and gradually diminished on POD 14. Insulin secretion decreased on POD 3 in association with a significant increase of HIF‐1α‐related β‐cell death, which can be suppressed by short‐term hyperbaric oxygen therapy. On POD 7, apoptosis was not further activated by continually produced HIF‐1α. In contrast, improvement of nerve growth factor and duodenal homeobox factor‐1 (PDx‐1) production resulted in islet graft recovery and remodeling. In addition, significant activation of vascular endothelial growth factor in islet grafts on POD 7 correlated with development of massive newly formed microvessels, whose maturation is advanced on POD 14 with gradual diminution of HIF‐1α. We conclude that (1) transplanted islets strongly express HIF‐1α in association with β‐cell death and decreased insulin production until adequate revascularization is established and (2) early suppression of HIF‐1α results in less β‐cell death thereby minimizing early graft failure.

Disparate distribution of 16 candidate single nucleotide polymorphisms among racial and ethnic groups of pediatric heart transplant patients

Background. Allograft failure in African-Americans remains higher than in Caucasians. Single nucleotide polymorphisms (SNPs) have been associated with altered allograft outcomes. Methods. In this multi-center study we compared SNP frequencies in 364 pediatric heart recipients from three ethnic/racial groups: Caucasian (n=243), African-American (n=39), and Hispanic (n=82). The target genes were: tumor necrosis factor-&agr;, interleukin (IL)-10, IL-6, interferon (IFN)-&ggr;, vascular endothelial growth factor (VEGF), transforming growth factor-&bgr;1, Fas, FasL, granzyme B, ABCB1, CYP3A5. Results. Compared to Caucasians, African-Americans exhibited a higher prevalence of genotypes associated with low expression of IFN-&ggr; (24% vs. 45.7%, P<0.001) and IL-10 (33% vs. 57.1%, P=0.052). African-Americans also exhibited an increased prevalence of high IL-6 (82.9% vs. 38.1%; P<0.001). VEGF −2578 C/C and −460 C/C genotypes were found more frequently in African-Americans and Hispanics as compared to Caucasians (P<0.001). G/G genotype of Fas and T/T genotype of FasL were expressed more often by African-American recipients. The prevalence of Granzyme B (−295A/G) genotype was differentially distributed in the three groups. Compared with Caucasians, African-Americans were twice as likely to carry the ABCB1 2677 G/G genotype (78.6% vs. 33.7%, P<0.0025), and they were more frequent carriers of the CYP3A5 *1/*1 genotype (35.7% vs. 0.6% in Caucasians and 7.2% in Hispanics; P<0.001). Conclusion. African-Americans have a genetic background that may predispose to proinflammatory/lower regulatory environment, reduced drug exposure and immunosuppressive efficacy. In this ongoing multicenter study, these gene polymorphisms differences among ethnic/racial groups are being documented so that therapeutic strategies can be devised to optimize outcomes for pediatric transplant recipients.

Dobutamine stress echocardiography for assessing coronary artery disease after transplantation in children

OBJECTIVES The purpose of this study was to determine the feasibility, safety and diagnostic accuracy of dobutamine stress echocardiography (DSE) for evaluating posttransplant coronary artery disease (TxCAD) in children, and to determine the frequency of selected cardiac events after normal or abnormal DSE. BACKGROUND Posttransplant coronary artery disease is the most common cause of graft loss (late death or retransplantation) after cardiac transplantation (CTx) in children. Coronary angiography, routinely performed to screen for TxCAD, is an invasive procedure with limited sensitivity. The efficacy of DSE for detecting atherosclerotic coronary artery disease is established, but is unknown in children after CTx. METHODS Of the 78 children (median age 5.7 years, range 3 to 18) entered into the study, 72 (92%) underwent diagnostic DSE by means of a standard protocol, 4.6 +/- 1.9 years after CTx. The results of coronary angiography performed in 70 patients were compared with DSE findings. After DSE, subjects were monitored for TxCAD-related cardiac events, including death, retransplantation and new angiographic diagnosis of TxCAD. RESULTS No major complications occurred. Minor complications, most often hypertension, occurred in 11% of the 72 subjects. The sensitivity and specificity of DSE were 72% and 80%, respectively, when compared with coronary angiography. At follow-up (21 +/- 8 months), TxCAD-related cardiac events occurred in 2 of 50 children (4%) with negative DSE, versus 6 of 22 children (27%) with positive DSE (p < 0.01). CONCLUSIONS DSE is a feasible, safe and accurate screening method for TxCAD in children. Positive DSE identifies patients at increased risk of TxCAD-related cardiac events. Negative DSE predicts short-term freedom from such events.

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-&agr;)−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-&agr; 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.