Early predictors of survival to and after heart transplantation in children with dilated cardiomyopathy.

BACKGROUND: The importance of clinical presentation and pretransplantation course on outcome in children with dilated cardiomyopathy listed for heart transplantation is not well defined. METHODS AND RESULTS: The impact of age, duration of illness, sex, race, ventricular geometry, and diagnosis of myocarditis on outcome in 261 children with dilated cardiomyopathy enrolled in the Pediatric Cardiomyopathy Registry and Pediatric Heart Transplant Study was studied. End points included listing as United Network for Organ Sharing status 1, death while waiting, and death after transplantation. The median age at the time of diagnosis was 3.4 years, and the mean time from diagnosis to listing was 0.62±1.3 years. Risk factors associated with death while waiting were ventilator use and older age at listing in patients not mechanically ventilated (P=0.0006 and P=0.03, respectively). Shorter duration of illness (P=0.04) was associated with listing as United Network for Organ Sharing status 1. Death after transplantation was associated with myocarditis at presentation (P=0.009), nonwhite race (P<0.0001), and a lower left ventricular end-diastolic dimension z score at presentation (P=0.04). In the myocarditis group, 17% (4 of 23) died of acute rejection after transplantation. CONCLUSIONS: Mechanical ventilator use and older age at listing predicted death while waiting, whereas nonwhite race, smaller left ventricular dimension, and myocarditis were associated with death after transplantation. Although 97% of children with clinically or biopsy-diagnosed myocarditis at presentation survived to transplantation, they had significantly higher posttransplantation mortality compared with children without myocarditis, raising the possibility that preexisting viral infection or inflammation adversely affects graft survival.

The impact of heart failure severity at time of listing for cardiac transplantation on survival in pediatric cardiomyopathy.

BACKGROUND: The survival benefit of heart transplantation in adult heart failure is greatest for the sickest patients and negligible for patients not requiring inotropic or mechanical support. We hypothesized a similar survival benefit of heart transplantation for childhood cardiomyopathies with heart failure. METHODS: A merged data set of children registered in both the Pediatric Cardiomyopathy Registry and the Pediatric Heart Transplant Study was used to assess differences in mortality before and after transplant in patients with different levels of heart failure severity. Severity was scored 2 if mechanical ventilatory or circulatory support was required, 1 if intravenous inotropes were required, or 0 if no support was required. RESULTS: For 332 eligible children, 12-month mortality after listing was 9% for those with a severity score of 0 (n = 105), 16% with a score of 1 (n = 118), and 26% with a score of 2 (n = 109; p = 0.002) with a 3%, 8%, and 20% mortality with severity scores at listing of 0, 1, and 2, respectively, occurring before transplant. Patients listed with a score of 0 frequently deteriorated: 50% received an allograft or died before transplant with severity scores of 1 or 2. The risk of deterioration increased with previous surgery (relative risk, 3.84; p = 0.03) in the short-term and with lower left ventricular mass z-score at time of presentation (relative risk, 1.74; p = 0.003) in the longer-term. CONCLUSION: Pediatric cardiomyopathy patients who require high levels of support receive a survival benefit from heart transplantation that is not shared by patients not requiring intravenous inotropic or mechanical support.

In situ pericardial extracardiac lateral tunnel Fontan operation: fifteen-year experience.

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.

Regional pulmonary blood flow in dogs by 4D-X-ray CT.

ECG-triggered computed tomography (CT) was used during passage of iodinated contrast to determine regional pulmonary blood flow (PBF) in anesthetized prone/supine dogs. PBF was evaluated as a function of height within the lung (supine and prone) as a function of various normalization methods: raw unit volume data (PBFraw) or PBF normalized to regional fraction air (PBFair), fractional non-air (PBFgm), or relative number of alveoli (PBFalv). The coefficient of variation of PBFraw, PBFair, PBFalv, and PBFgm ranged between 30 and 50% in both lungs and both body postures. The position of maximal flow along the height of the lung (MFP) was calculated for PBFraw, PBFair, PBFalv, and PBFgm. Only PBFgm showed a significantly different MFP height supine vs. prone (whole lung: 2.60 +/- 1.08 cm supine vs. 5.08 +/- 1.61 cm prone, P < 0.01). Mean slopes (ml/min/gm water content/cm) of PBFgm were steeper supine vs. prone in the right (RL) but not left lung (LL) (RL: -0.65 +/- 0.29 supine vs. -0.26 +/- 0.25 prone, P < 0.02; LL: -0.47 +/- 0.21 supine vs. -0.32 +/- 0.26 prone, P > 0.10). Mean slopes of PBFgm vs. vertical lung height were not different prone vs. supine above this vertical height of MFP (VMFP), but PBFgm slopes were steeper in the supine position below the VMFP in the RL. We conclude that PBFgm distribution was posture dependent in RL but not LL. Support of the heart may play a role. We demonstrate that normalization factors can lead to differing attributions of gravitational effects on PBF heterogeneity.

Effect of oversizing cardiac allografts on survival in pediatric patients with congenital heart disease.

BACKGROUND: There are few published data regarding the long-term outcome of "large" cardiac allografts in children. This study examines the effect of cardiac graft oversizing on the survival of pediatric patients with congenital heart disease (CHD). METHODS: Two hundred ninety-one children, age 1 day to 17 years (median 50 days), with CHD underwent primary cardiac transplantation between 1985 and 2002. Patients were analyzed according to donor-recipient weight ratio (D-R): Group (Gp) I (n = 252) with D-R <2.5 (range 0.59 to 2.49, median 1.4), and Gp II (n = 39) with D-R >/=2.5 (range 2.5 to 4.65, median 2.78). CHD diagnoses included hypoplastic left heart syndrome (138 in Gp I, 13 in Gp II), single ventricle (29 in Gp I, 1 in Gp II) and other (85 in Gp I, 13 in Gp II). Patients with cardiomyopathy were excluded. Pre-transplant cardiac palliation was performed in 36% of Gp I and 15% of Gp II patients. The average graft ischemic times (minutes) were 266 +/- 7.5 and 283 +/- 18.9 for Gp I and Gp II, respectively (p < 0.2). RESULTS: The operative mortality for Gp I was 10.3% and 10.2% for Gp II (p < 0.99). There was no significant difference between the 2 groups in length of hospital stay (p < 0.15) or duration of ventilator support (p < 0.6) post-transplantation. However, the incidence of open chest was higher (p < 0.003) in Gp II (28%) compared with Gp I (8%). The survival rates for Gp I and Gp II were: 82 +/- 2.4% vs 84 +/- 5.7% at 1 year; 71 +/- 2.9% vs 72 +/- 7.2% at 5 years; and 63 +/- 3.2% vs 65% +/- 7.4 at 10 years. CONCLUSIONS: Post-transplant morbidity and short- and long-term survival of pediatric recipients with CHD are not adversely influenced by the use of oversized cardiac allografts.

Exercise assessment in infants after cardiac transplantation.

BACKGROUND: 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. METHODS: 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]). RESULTS: 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, p <0.001). Peak oxygen consumption was 14% less in the recipients (32.3 +/- 5.6 ml/kg/min vs 36.8 +/- 5.5 ml/kg/min, p <0.01). Ventilatory anaerobic threshold was decreased in recipients, 27.6 +/- 9.6 vs 32.8 +/- 6.0, p <0.05. 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). CONCLUSIONS: 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.

Effect of a selection and postoperative care protocol on survival of infants with hypoplastic left heart syndrome.

BACKGROUND: We report the development and implementation of a program designed to assign patients preoperatively to either transplant or Norwood procedure based on a score derived from known risk factors and to enhance postoperative care of infants undergoing the Norwood procedure. METHODS: A weighted score for each of six variables comprised the scoring system: ventricular function, tricuspid regurgitation, ascending aortic diameter, atrial septal defect blood flow characteristics, blood type, and age. The scoring system was used to prospectively assign mortality risk and lead to recommendation of either Norwood procedure or transplantation. RESULTS: Survival following the Norwood procedure significantly improved after the management program was implemented (88% versus 40% at 48 hours, 57% versus 10% at 30 days, and 50% versus 10% at 1 year, p < 0.0001 at each time point). The survival of the group that received a score of 7 or less (high risk) who underwent the Norwood procedure was 78% at 48 hours, 44% at 30 days, and 33% at 1 year; survival rates among patients considered lower risk (greater than 7) were 100% at 48 hours and 80% at 30 days and 1 year. Transplant outcomes remained unchanged. CONCLUSIONS: We report improved survival following the Norwood procedure after the implementation of an institutional management approach aimed at improving the outcome of infants with hypoplastic left heart syndrome and may help neutralize historical biases toward Norwood procedure or transplantation.

Scoring system to determine need for balloon atrial septostomy for restrictive interatrial communication in infants with hypoplastic left heart syndrome.

BACKGROUND: 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). METHODS: 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 saturation <80% 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. RESULTS: Only 10% of infants with a score <6 at presentation required BAS, whereas 67% of those with scores > or =6 required BAS. Higher IAC scores at presentation were associated with earlier need for BAS (p = 0.04). CONCLUSIONS: 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.

Moderate acute rejection detected during annual catheterization in pediatric heart transplant recipients.

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 1108 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.

Usefulness of cardiac transplantation in children with visceral heterotaxy (asplenic and polysplenic syndromes and single right-sided spleen with levocardia) and comparison of results with cardiac transplantation in children with dilated cardiomyopathy.

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.

Infected cardiac myxoma.

Infected cardiac myxoma is a rare condition with variable presentation. We report a case of infected cardiac myxoma which presented as fever of unknown origin. Diagnostic considerations and treatment of this condition are discussed.