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OBJECTIVESThe study objectives were to determine posttransplant coronary artery disease (TxCAD) incidence, predisposing factors and optimal timing for retransplantation (re-Tx) in pediatric heart transplantation (Tx) recipients.BACKGROUNDThe TxCAD limits long-term survival following heart Tx, with re-Tx being the primary therapy. Information on risk factors and timing of listing for re-Tx is limited in children.METHODSThe records of children who survived >1 year post-Tx at Loma Linda University were reviewed. Nonimmune and immune risk factors were analyzed.RESULTSTxCAD was documented in 24 of 210 children. Freedom from TxCAD was 92 ± 2% and 75 ± 5% at 5 and 10 years’ post-Tx, respectively. The TxCAD diagnosis was established at autopsy in 10 asymptomatic patients who died suddenly within nine months following the most recent negative angiograms. The remaining 14 children had angiographic diagnoses of TxCAD and had symptoms and/or graft dysfunction (n = 10) or positive stress studies (n = 4). Three of 14 died within three months after the diagnosis was made. Eleven patients underwent re-Tx within seven months of diagnosis; nine survived. Univariate and multivariate analyses showed that only late rejection (>1 year posttransplant) frequency (p = 0.025) and severity (hemodynamically compromising) (p < 0.01) were independent predictors of TxCAD development. Freedom from TxCAD after severe late rejection was 78 ± 8% one year postevent and 55 ± 10% by two years.CONCLUSIONSLate rejection is an independent predictor of TxCAD. Patients suffering severe late rejection develop angiographically apparent TxCAD rapidly and must be monitored aggressively. Both TxCAD mortality and morbidity occur early; therefore, we recommend immediate listing for re-Tx upon diagnosis.

Objectives. This study was undertaken to investigate the incidence of posttransplant recoarctation of the aorta, delineate the mode of presentation, identify risk factors that predict recoarctation and examine the results of intervention for posttransplant recoarctation.Background. Patients with aortic arch hypoplasia require extended arch reconstruction at transplant, with an inherent possibility of subsequent recoarctation of the aorta.Methods. This was a retrospective review of all children (age

We report an infant who had tetralogy of Fallot, hypoplastic pulmonary arteries, and membranous pulmonary atresia who underwent successful perforation of the atretic valve and subsequent balloon pulmonary valvuloplasty. Because of the inability to access the pulmonary arteries via a patent ductus arteriosus, two-dimensional echocardiography was used to confirm wire position prior to perforation. The branch pulmonary arteries initially measured 1.5 mm in diameter and enlarged to 2.8 mm immediately after valvuloplasty. Four months postprocedure, the patient underwent a successful repeat balloon pulmonary valvuloplasty. The pulmonary arteries had grown to approximately 6 mm in diameter. Although it is a rare occurrence, patients with tetralogy of Fallot and membranous pulmonary atresia can be dilated with successful growth of the pulmonary arteries.

Early left ventricular (LV) remodeling following pediatric cardiac transplantation has not been described. To identify patterns and determinants of change in left ventricular mass and volume posttransplant, we studied 125 consecutive children who underwent cardiac transplantation between January 1, 1989 and July 31, 1993. Two-dimensional imaging-directed M-mode echocardiograms were studied weekly until 26 weeks post-transplant. LV mass and volume (indexed to BsA 1.5 ) were measured. LV mass index increased until 3 weeks post-transplant, and then decreased. The mean decrement in LV mass index after 8 weeks post-transplant (relative to baseline) was significantly larger in patients with donor-recipient weight ratio >1.5 compared with patients with donor-recipient weight ratio ≤1.5 (-2.2 g/m 3 compared with 33.4 g/m 3 , respectively, P

Objective Children born with hypoplastic left heart syndrome (HLHS) may experience cardiac dysfunction after staged surgery or transplantation, which may worsen with age. We examined the hypothesis that exercise testing can address cardiovascular capacity and suggest interventions to improve quality of life. Study design Children with HLHS ≥8 years old performed treadmill or bicycle ergometric testing at 4 centers. Results were compared with norms for age and sex. Results Of the 42 participants, the mean age was 12.9 years (range, 8.5-17.0 years), 64% were boys, 20 had staged surgery, and 34 completed metabolic assessment. The percent of predicted maximal oxygen uptake (mVO2) was higher in younger children. Children aged 8 to 12 years achieved 70% of predicted mVO2; children aged 13 to 17 years achieved 60% of predicted mVO2 ( P = .02). The percent of predicted peak heart rate trended higher in younger patients (83% versus 75%, P = .07). Electrocardiographic changes were more common in older children. In treadmill testing, patients who had a transplant had better exercise performance than patients who underwent staged surgery in percent of predicted exercise time (82% versus 54%, P 3 versus 195 × 10 3 , P = .02). The percent of predicted mVO2 did not differ between patients who had a transplant (66%) and patients who underwent staged surgery (61%, P = .25). Conclusion Children with HLHS showed considerable age-related decline in exercise performance, regardless of surgical strategy.

The blood anion nitrite contributes to hypoxic vasodilation through a heme-based, nitric oxide (NO)-generating reaction with deoxyhemoglobin and potentially other heme proteins. We hypothesized that this biochemical reaction could be harnessed for the treatment of neonatal pulmonary hypertension, an NO-deficient state characterized by pulmonary vasoconstriction, right-to-left shunt pathophysiology and systemic hypoxemia. To test this, we delivered inhaled sodium nitrite by aerosol to newborn lambs with hypoxic and normoxic pulmonary hypertension. Inhaled nitrite elicited a rapid and sustained reduction ( approximately 65%) in hypoxia-induced pulmonary hypertension, with a magnitude approaching that of the effects of 20 p.p.m. NO gas inhalation. This reduction was associated with the immediate appearance of NO in expiratory gas. Pulmonary vasodilation elicited by aerosolized nitrite was deoxyhemoglobin- and pH-dependent and was associated with increased blood levels of iron-nitrosyl-hemoglobin. Notably, from a therapeutic standpoint, short-term delivery of nitrite dissolved in saline through nebulization produced selective, sustained pulmonary vasodilation with no clinically significant increase in blood methemoglobin levels. These data support the concept that nitrite is a vasodilator acting through conversion to NO, a process coupled to hemoglobin deoxygenation and protonation, and evince a new, simple and inexpensive potential therapy for neonatal pulmonary hypertension.

Restrictive interatrial communication (IAC) causes morbidity and mortality in infants with hypoplastic left heart syndrome awaiting cardiac transplantation. We sought to create a scoring system, based on echocardiographic and clinical findings, to serve as a guide for determining the need for balloon atrial septostomy (BAS).We retrospectively reviewed echocardiograms of 44 infants with hypoplastic left heart syndrome. Infants were studied from the time of admission to the final end-point of transplantation, Norwood procedure, or death. Seventeen infants underwent BAS for clinical indications of oxygen saturation80% in room air. Data collected included age at BAS, maximum velocity (V(max)), and IAC diameter throughout the clinical course. We assigned higher IAC scores to smaller IAC diameter, greater V(max) through the IAC, and lower oxygen saturation value. The minimum score was 3, and the maximum score was 9.Only 10% of infants with a score6 at presentation required BAS, whereas 67% of those with scoresor =6 required BAS. Higher IAC scores at presentation were associated with earlier need for BAS (p = 0.04).The IAC scoring system can serve as a reliable clinical guide for identifying infants with hypoplastic left heart syndrome who are likely to require BAS for relief of critically restrictive IAC while awaiting cardiac transplantation.

Few data describe exercise performance after cardiac transplantation during infancy. The aim of this study was to compare the cardiorespiratory response to exercise in healthy subjects with that of subjects who had undergone heart transplantation during infancy to treat hypoplastic left heart syndrome.Subjects (24 heart transplant recipients and 25 healthy controls) exercised on a treadmill using pediatric ramp protocols. We measured heart rate (HR), blood pressure, and metabolic data. Median age at transplantation was 20 days (range, 4 to 97 days). Age of recipients at exercise testing was 9.7 +/- 2.3 years and in healthy subjects was 10.5 +/- 1.4 years (p=not significant [NS]).Exercise duration was similar in both groups (10.3 +/- 2.0 minutes in recipients vs 11.1 +/- 1.5 minutes in healthy subjects, (p=NS). Heart rate at rest was greater in recipients (94 +/- 15 beats per minute [bpm] vs 85 +/- 11 bpm, p=0.02). Peak HR also was less in the recipient group (158 +/- 15 bpm vs 189 +/- 12 bpm, p0.001). Peak oxygen consumption was 14% less in the recipients (32.3 +/- 5.6 ml/kg/min vs 36.8 +/- 5.5 ml/kg/min, p0.01). Ventilatory anaerobic threshold was decreased in recipients, 27.6 +/- 9.6 vs 32.8 +/- 6.0, p0.05. Respiratory exchange ratio at peak exercise was equal in both groups (1.06 +/- 0.06 vs 1.06 +/- 0.08). Oxygen pulse index did not differ significantly, 5.5 +/- 1.1 ml/beat/m2 in recipients and 6.1 +/- 1.7 ml/beat/m2 in healthy subjects (p=NS).Overall, children who undergo cardiac transplantation in infancy have exercise capacities within the normal range. These recipients have a decreased heart rate reserve that may account for the differences in peak oxygen consumption when compared with healthy subjects.

Background: Acute rejection commonly occurs within the first year after heart transplantation, and then decreases in frequency with time. Recently, the long-term utility of endomyocardial biopsy during routine annual catheterization has been questioned. The purpose of this study was to retrospectively review the prevalence of biopsy-proven rejection during routine annual catheterization in our patient population, determine whether biopsies late after transplant are useful, and identify factors that correlate with late unsuspected rejection. Methods: Biopsy results from the annual catheterization were evaluated from 1986 to August 2000. The prevalence of moderate rejection was evaluated and compared with the patient's immunosuppressive regimen; the prevalence of late rejection; and how late rejection correlated with recipient age, number of first-year rejections and presence of sub-therapeutic cyclosporine. Results: A total of 1,108 biopsies were performed in 269 children with a mean follow-up of 5 ± 3 years (median 5 years, range 1 to 11 years). Three-drug immunosuppressive therapy, including steroids, was used in 93 patients. There was a persistent 8% to 10% prevalence of moderate rejection at up to 10 years post-transplantation. Moderate rejection was more likely in patients: (1) on 3-drug immunosuppressive therapy; (2) with a recipient age >1 year; and (3) with a relatively lower cyclosporine level. Conclusions: These data suggest that continued surveillance of pediatric transplant patients for acute rejection is indicated for long-term follow-up.

Surgical mortality is high in children with visceral heterotaxy (VH), particularly if atrioventricular valve insufficiency, ventricular dysfunction, or aortic atresia is present. This study reviews the outcome of cardiac transplantation (CT) in infants and children with VH and congenital heart disease who are at high risk for standard palliative or corrective surgery. We reviewed CT outcomes in 29 children with VH, congenital heart disease, atrioventricular valve insufficiency, ventricular dysfunction, and/or aortic atresia. Median age at CT was 3.1 years. Cardiac surgery had been performed in 20 patients (69%) before CT. Follow-up since CT has been 8.5 +/- 2.2 years. Outcomes were compared with 45 children who underwent transplantation for dilated cardiomyopathy. Actuarial graft survival in the VH group at 30 days and 1, 5, and 10 years was 100%, 86%, 68%, and 50%, respectively, compared with 100%, 96%, 83%, and 68% in children who underwent transplantation for dilated cardiomyopathy (p = 0.12). Splenic status, cardiac position, age at CT, number of prior cardiac surgeries, or systemic venous anomalies were not predictors of mortality after CT. Cardiopulmonary bypass and graft ischemic times were longer in the VH group; time on the ventilator after CT, length of hospitalization, and rejection, infection, post-transplant lymphoproliferative disease, and transplant coronary artery disease rates were equal. Thus, CT is a viable alternative therapy for high-risk patients with VH, possibly offering improved survival over standard surgical management.

This study evaluated the procedural and long-term outcome of infants who underwent atrial septostomy while awaiting transplant. The results suggest that septostomy improved outcome in these patients although infants needing a transseptal perforation were at higher risk.

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 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.

Limited data are available on exercise performance after infant cardiac transplantation (CTX). Purpose: The aim of this study was to compare the cardiorespiratory response to exercise in children who had undergone CTX for hypoplastic left heart syndrome in infancy with normal (NML) subjects. Procedure: Subjects (24 CTX; 25 NML) were exercised on a treadmill using pediatric ramp protocols. Heart rate (HR), blood pressure (BP), oxygen consumption (VO2), CO2 production and ventilatory anaerobic threshold (VAT) were measured. Mean age at CTX was 32±26 days. Age of CTX subjects at time of exercise was 9.7±2.3 years and 10.5±1.4 years in NML subjects (p=NS). All subjects in both groups were NYHA Class I. Results: Exercise duration was similar (p=NS) in both groups (10.3±2.0 minutes(CTX) versus 11.1±1.5 minutes (NML). HR at rest was greater in CTX patients (94±15 BPM versus 85±11 BPM (p=0.02). Peak HR was also less in the CTX group (158 BPM±15 BPM versus 189 BPM±12 BPM (p Conclusions: 1) Overall, children receiving cardiac transplantation in infancy have an exercise capacity within the normal range. 2) Subjects undergoing cardiac transplantation in early infancy have decreased heart rate reserve that may account for the differences in peak oxygen consumption compared to normal subjects.

Background The study purpose is to evaluate the long-term outcome of the in situ pericardial extracardiac lateral tunnel Fontan operation. Methods From June 1994 to August 2009, 160 patients with single ventricle (boys, n = 96, 60%, median age = 39 months, mean weight 15.5 kg) underwent the pedicled pericardial extracardiac lateral tunnel operation. Patients' charts were reviewed for perioperative and long-term follow-up data, outcome, and mortality. The potential growth of these tunnels was evaluated. Results The main diagnoses included tricuspid atresia (n = 44, 27%); double-outlet right ventricle (n = 29, 18%), and hypoplastic left heart syndrome (n = 26, 16%). The mean follow-up was 6.5 ± 3.7 years (range: 0.1–15 years). There were 2 (1.3%) operative and 6 (3.7%) late deaths. Actuarial survival at 14 years was 93%. Early complications included prolonged effusions (n = 35, 22%), chylothorax (n = 5, 3.1%), readmissions (n = 35, 22%), cerebrovascular accidents (n = 8, 5%), contralateral phrenic nerve palsy (n = 1, 0.8%), and transient arrhythmias (n = 5, 3.1%). No pacemaker was needed. Late complications included tunnel stenosis (n = 3, 1.8%) managed with balloon dilatation and stenting in 2 patients and surgical revision in 1; tunnel thrombosis (n = 2, 1.2%) causing death in both patients; and protein losing-enteropathy (n = 4, 2.5%). Follow-up echocardiography of 10 patients showed laminar flow, no turbulence/gradient at the inferior vena cava and mid-tunnel levels. The diameter indexed to body surface area showed growth, reduction, or no change depending on flow demands. Conclusions The construction of the extracardiac lateral tunnel Fontan conduit using viable pedicled pericardium is a relatively simple, durable, and safe operation. Long-term follow-up confirms low morbidity and mortality. Fenestration is unnecessary in most patients. This viable tunnel adapts to physiologic flow demands.