Genetic Testing Resources and Practice Patterns Among Pediatric Cardiomyopathy Programs

The use of genetic testing has enhanced the diagnostic accuracy of heritable genetic cardiomyopathies. However, it remains unclear how genetic information is interpreted and incorporated into clinical practice for children with cardiomyopathy. The primary aim of this study was to understand how clinical practice differs regarding sequence variant classifications amongst pediatric cardiologists who treat children with cardiomyopathy. A secondary aim was to understand the availability of genetic testing and counseling resources across participating pediatric cardiomyopathy programs. An electronic survey was distributed to pediatric heart failure, cardiomyopathy, or heart transplantation physicians between August and September 2022. A total of 106 individual providers from 68 unique centers responded to the survey. Resources for genetic testing and genetic counseling vary among large pediatric cardiomyopathy programs. A minority of centers reported having a geneticist (N = 16, 23.5%) or a genetic counselor (N = 21, 31%) on faculty within the division of pediatric cardiology. A total of 9 centers reported having both (13%). Few centers (N = 13, 19%) have a formal process in place to re-engage patients who were previously discharged from cardiology follow-up if variant reclassification would alter clinical management. Clinical practice patterns were uniform in response to pathogenic or likely pathogenic variants but were more variable for variants of uncertain significance. Efforts to better incorporate genetic expertise and resources into the clinical practice of pediatric cardiomyopathy may help to standardize the interpretation of genetic information and better inform clinical decision-making surrounding heritable cardiomyopathies.

Long-term outcomes for pediatric heart transplant recipients transitioning to adult care teams

BACKGROUND

There are limited data evaluating the success of a structured transition plan specifically for pediatric heart transplant (HT) recipients following their transfer of care to an adult specialist. We sought to identify risk factors for poor adherence, graft failure, and mortality following the transfer of care to adult HT care teams.

METHODS

We retrospectively reviewed all patients who underwent transition from the pediatric to adult HT program at our center between January 2011 and June 2021. Demographic characteristics, comorbid conditions, and psychosocial history were collected at the time of HT, the time of transition, and the most recent follow-up. Adverse events including mortality, graft rejection, infection, and renal function were also captured before and after the transition.

RESULTS

Seventy-two patients were identified (54.1% male, 54.2% Caucasian). Mean age at the time of transition was 23 years after a median of 11.6 years in the pediatric program. The use of calcineurin inhibitors was associated with reduced mortality (HR .04, 95% CI .0-.6, p = .015), while prior psychiatric hospitalization (HR 45.3, 95% CI, 6.144-333.9, p = .0001) was associated with increased mortality following transition. Medication nonadherence and young age at the time of transition were markers for high-risk individuals prior to the transition of care.

CONCLUSIONS

Transition of HT recipients from a pediatric program to an adult program occurs during a vulnerable time of emerging adulthood, and we have identified risk factors for mortality following transition. Development of a formalized transition plan with a large multidisciplinary team with focused attention on high-risk patients, including those with psychiatric comorbidities, may favorably influence outcomes.

Association Between High Sensitivity Troponin Levels Following Pediatric Orthotopic Heart Transplantation and Intensive Care Unit Resource Utilization

The utility of troponin levels, including high sensitivity troponin T (hs-TnT), after orthotopic heart transplant (OHT) is controversial. Conflicting data exist regarding its use as a marker of acute rejection. Few studies have examined possible associations of hs-TnT levels immediately after OHT with metrics of intensive care unit (ICU) resource utilization or risk of acute rejection. We performed a retrospective cohort chart review including all OHT recipients < 20 years of age at our center between June 2019 and December 2022. Patients were divided into two groups based on supra- or sub-median initial hs-TnT levels (median 3462.5 ng/L). Primary outcome was days requiring ICU-level care, secondary outcomes included days intubated, days requiring positive pressure ventilation (PPV), days on inotropic medications, actual ICU length of stay, Vasoactive Inotrope Scores (VIS) on postoperative days (POD) 0 through 7, and acute rejection at 30 days and one year after OHT. Patients with higher hs-TnT required ICU level care for longer [13.5 (10-17.5) vs. 9.5 (8-12) days, p = 0.01] and spent more days intubated [6 (4-7) vs. 3 (3-5) days, p < 0.001], on PPV [9 (6-15) vs. 6 (5-8.5) days, p = 0.02], and on inotropes [11 (9-14) vs. 8 (7-11) days, p = 0.025]. VIS was only different between groups on POD7 [5 (3-7) vs. 3 (0-5), p = 0.04]. There was no difference in rejection between the groups. Higher hs-TnT immediately following pediatric OHT may predict higher ICU resource utilization, despite no difference in VIS, although it does not predict acute rejection in the first year after OHT.

Contemporary outcomes of pediatric cardiac transplantation with a positive retrospective crossmatch

BACKGROUND

A positive crossmatch (+ XM) has traditionally been associated with adverse outcomes following pediatric heart transplantation. However, more recent studies suggest that favorable intermediate-term outcomes may be achieved despite a + XM. This study's hypothesis is that children with a + XM have similar long-term survival, but higher rate of complications such as rejection, coronary allograft vasculopathy (CAV), and infection, compared to patients with a negative (-) XM.

METHODS

The Pediatric Heart Transplant Society Registry (PHTS) database was queried from 2010-2021 for all patients <18 years of age with a known XM. Baseline demographics were compared between + XM and - XM groups using appropriate parametric and non-parametric group comparisons. Cox Proportional Hazards Modeling was used to identify risk factors for post-transplant graft loss, rejection, and CAV.

RESULTS

Of 4599 pediatric heart transplants during the study period, XM results were available for 3914 (85%), of which 373 (9.5%) had a + XM. Univariate analysis showed lower 10-year survival for patients with + XM (HR = 1.3, p = .04). Multivariate analyses revealed no significant difference in 10-year survival in the 2 groups; however, time to first rejection (p = .0001) remained significantly shorter in the + XM group.

CONCLUSIONS

Pediatric patients transplanted across a + XM experience earlier rejection; however, after multivariate adjustment, + XM is not independently associated with intermediate-term graft loss. The risk of heart transplantation against a + XM must be balanced with the ongoing risk of waitlist mortality.

Elevated cardiac biomarkers and outcomes in children and adolescents with acute COVID-19

Cardiac involvement associated with multi-system inflammatory syndrome in children has been extensively reported, but the prevalence of cardiac involvement in children with SARS-CoV-2 infection in the absence of inflammatory syndrome has not been well described. In this retrospective, single centre, cohort study, we describe the cardiac involvement found in this population and report on outcomes of patients with and without elevated cardiac biomarkers. Those with multi-system inflammatory syndrome in children, cardiomyopathy, or complex CHD were excluded. Inclusion criteriaz were met by 80 patients during the initial peak of the pandemic at our institution. High-sensitivity troponin T and/or N-terminal pro-brain type natriuretic peptide were measured in 27/80 (34%) patients and abnormalities were present in 5/27 (19%), all of whom had underlying comorbidities. Advanced respiratory support was required in all patients with elevated cardiac biomarkers. Electrocardiographic abnormalities were identified in 14/38 (37%) studies. Echocardiograms were performed on 7/80 patients, and none demonstrated left ventricular dysfunction. Larger studies to determine the true extent of cardiac involvement in children with COVID-19 would be useful to guide recommendations for standard workup and management.

Immune cell function assay and T lymphocyte counts lack association with rejection or infection in pediatric heart transplant recipients

INTRODUCTION

Immune cell function assay (ICFA) and CD3 lymphocyte counts have been considered to be useful in discerning the overall intensity of immunosuppression in pediatric orthotopic heart transplant (OHT) recipients.

METHODS

The aim of this retrospective analysis was to evaluate trends of ICFA and CD3 lymphocyte counts and their association with adverse outcomes post-OHT.

RESULTS

A total of 381 ICFA and 493 CD3 laboratory values obtained in 78 patients within six months post-OHT were analyzed. There were 14 patients treated for biopsy-proven acute rejection, four of whom had ISHLT grade 2R/3A rejection. In patients with rejection versus those without, CD3 and ICFA values were 122 (IQR 74.5-308) cells/mm² and 224.5 (IQR 132-343.5) ng/ml compared to 231.8 (IQR 68-421) cells/m² and 191 (IQR 81.5-333) ng/mL (p = NS for both). Twenty-six patients had at least one detectable cytomegalovirus or Epstein-Barr virus DNAemia within the study timeframe. In patients with viremia versus those without, CD3 and ICFA values were 278.5 (IQR 68-552) cells/mm² and 130 (IQR 48-284) ng/ml compared to 195 (IQR 74.5-402.5) cells/mm² and 212 (IQR 89-342) ng/ml (p = NS for both).

CONCLUSIONS

No association was found between these immune markers and adverse outcomes. In the absence of larger pediatric studies justifying the role of these tests in identifying elevated risk profiles post OHT, we do not recommend their routine use.

Worsening racial disparity in waitlist mortality for pediatric heart transplant candidates since the 2016 Pediatric Heart Allocation Policy revision

BACKGROUND

The US Pediatric Heart Allocation Policy (PHAP) was revised in March 2016, with the goal of reducing waitlist mortality. We evaluated the hypothesis that these changes, which increased status exceptions, have worsened racial disparities in waitlist outcomes.

METHODS

Children in the Pediatric Heart Transplant Study database listed for first heart transplant from January 2012 - June 2020 were included and stratified by listing before (Era 1) or after (Era 2) the PHAP revision.

RESULTS

A total of 4,089 children were listed during the study period. Compared with white children (n = 2648), non-white children (n = 1441) were more likely to have an underlying diagnosis of cardiomyopathy in both eras. Waitlist mortality was similar in white and non-white children in Era 1, but comparatively worse for non-white children in Era 2. In multivariable analysis controlling for diagnosis, age, and severity markers, non-white children had a significantly higher waitlist mortality only in Era 2 (Era 1: sHR 1.22 [95%CI 0.90 - 1.66] vs. Era 2: sHR 1.57 [95%CI 1.17 - 2.10]).

CONCLUSIONS

Widening racial disparities in waitlist mortality may be an unintended consequence of the 2016 PHAP revision. Additional analyses may inform the degree to which this policy vs. unrelated changes in care differentially contribute to these disparities.

Varying presentations of COVID-19 in young heart transplant recipients: A case series

BACKGROUND

Immunosuppression is considered a risk factor for more severe clinical presentation of COVID-19. Limited data regarding clinical outcome exist in adults, whereas very little is known about the spectrum of the disease in pediatric heart transplant recipients.

METHODS

We retrospectively reviewed the charts of young heart transplant patients from our tertiary care center during the coronavirus pandemic in New York City and identified patients infected with SARS-CoV-2.

RESULTS

We present four cases with COVID-19 disease and elaborate on their presentation and clinical course.

CONCLUSIONS

Although far from conclusive and limited by the small sample size and selection bias, these cases demonstrate mild and self-limited disease despite immunosuppressive therapy and various comorbidities that are expected to increase the severity of the clinical picture based on extrapolation from the adult experience with this novel disease.

Pediatric Heart Network Echocardiographic Z Scores: Comparison with Other Published Models

BACKGROUND

Different methods have resulted in variable Z scores for echocardiographic measurements. Using the measurements from 3,215 healthy North American children in the Pediatric Heart Network (PHN) echocardiographic Z score database, the authors compared the PHN model with previously published Z score models.

METHODS

Z scores were derived for cardiovascular measurements using four models (PHN, Boston, Italy, and Detroit). Model comparisons were performed by evaluating (1) overlaid graphs of measurement versus body surface area with curves at Z = -2, 0, and +2; (2) scatterplots of PHN versus other Z scores with correlation coefficients; (3) Bland-Altman plots of PHN versus other Z scores; and (4) comparison of median Z scores for each model.

RESULTS

For most measurements, PHN Z score curves were similar to Boston and Italian curves but diverged from Detroit curves at high body surface areas. Correlation coefficients were high when comparing the PHN model with the others, highest with Boston (mean, 0.99) and lowest with Detroit (mean, 0.90). Scatterplots suggested systematic differences despite high correlations. Bland-Altman plots also revealed poor agreement at both extremes of size and a systematic bias for most when comparing PHN against Italian and Detroit Z scores. There were statistically significant differences when comparing median Z scores between the PHN and other models.

CONCLUSIONS

Z scores from the multicenter PHN model correlated well with previous single-center models, especially the Boston model, which also had a large sample size and similar methodology. The Detroit Z scores diverged from the PHN Z scores at high body surface area, possibly because there were more subjects in this category in the PHN database. Despite excellent correlation, significant differences in Z scores between the PHN model and others were seen for many measurements. This is important when comparing publications using different models and for clinical care, particularly when Z score thresholds are used to guide diagnosis and management.

Impact of Coronavirus Disease 2019 (COVID-19) on Patients With Congenital Heart Disease Across the Lifespan: The Experience of an Academic Congenital Heart Disease Center in New York City

Background We sought to assess the impact and predictors of coronavirus disease 2019 (COVID-19) infection and severity in a cohort of patients with congenital heart disease (CHD) at a large CHD center in New York City. Methods and Results We performed a retrospective review of all individuals with CHD followed at Columbia University Irving Medical Center who were diagnosed with COVID-19 between March 1, 2020 and July 1, 2020. The primary end point was moderate/severe response to COVID-19 infection defined as (1) death during COVID-19 infection; or (2) need for hospitalization and/or respiratory support secondary to COVID-19 infection. Among 53 COVID-19-positive patients with CHD, 10 (19%) were <18 years of age (median age 34 years of age). Thirty-one (58%) had complex congenital anatomy including 10 (19%) with a Fontan repair. Eight (15%) had a genetic syndrome, 6 (11%) had pulmonary hypertension, and 9 (17%) were obese. Among adults, 18 (41%) were physiologic class C or D. For the entire cohort, 9 (17%) had a moderate/severe infection, including 3 deaths (6%). After correcting for multiple comparisons, the presence of a genetic syndrome (odds ratio [OR], 35.82; P=0.0002), and in adults, physiological Stage C or D (OR, 19.38; P=0.002) were significantly associated with moderate/severe infection. Conclusions At our CHD center, the number of symptomatic patients with COVID-19 was relatively low. Patients with CHD with a genetic syndrome and adults at advanced physiological stage were at highest risk for moderate/severe infection.

Utilization and Outcomes of Children Treated with Direct Thrombin Inhibitors on Paracorporeal Ventricular Assist Device Support

Thrombotic and bleeding complications have historically been major causes of morbidity and mortality in pediatric ventricular assist device (VAD) support. Standard anticoagulation with unfractionated heparin is fraught with problems related to its heterogeneous biochemical composition and unpredictable pharmacokinetics. We sought to describe the utilization and outcomes in children with paracorporeal VAD support who are treated with direct thrombin inhibitors (DTIs) antithrombosis therapy. Retrospective multicenter review of all pediatric patients (aged <19 years) treated with a DTI (bivalirudin or argatroban) on paracorporeal VAD support, examining bleeding and thrombotic adverse events. From May 2012 to 2018, 43 children (21 females) at 10 centers in North America, median age 9.5 months (0.1-215 months) weighing 8.6 kg (2.8-150 kg), were implanted with paracorporeal VADs and treated with a DTI. Diagnoses included cardiomyopathy 40% (n = 17), congenital heart disease 37% (n = 16; single ventricle n = 5), graft vasculopathy 9% (n = 4), and other 14% (n = 6). First device implanted included Berlin Heart EXCOR 49% (n = 21), paracorporeal continuous flow device 44% (n = 19), and combination of devices in 7% (n = 3). Adverse events on DTI therapy included; major bleeding in 16% (n = 7) (2.6 events per 1,000 patient days of support on DTI), and stroke 12% (n = 5) (1.7 events per 1,000 patient days of support on DTI). Overall survival to transplantation (n = 30) or explantation (n = 8) was 88%. This is the largest multicenter experience of DTI use for anticoagulation therapy in pediatric VAD support. Outcomes are encouraging with lower major bleeding and stroke event rate than that reported in literature using other anticoagulation agents in pediatric VAD support.

Cardiac workup and monitoring in hospitalised children with COVID- 19

Approximately, 1.7 million individuals in the United States have been infected with SARS-CoV-2, the virus responsible for the novel coronavirus disease-2019 (COVID-19). This has disproportionately impacted adults, but many children have been infected and hospitalised as well. To date, there is not much information published addressing the cardiac workup and monitoring of children with COVID-19. Here, we share the approach to the cardiac workup and monitoring utilised at a large congenital heart centre in New York City, the epicentre of the COVID-19 pandemic in the United States.

Implantable Cardioverter Defibrillator Use in Males with Duchenne Muscular Dystrophy and Severe Left Ventricular Dysfunction

Duchenne muscular dystrophy (DMD) is characterized by myocardial fibrosis and left ventricular (LV) dysfunction. Implantable cardioverter defibrillator (ICD) use has not been characterized in this population but is considered for symptomatic patients with severe LV dysfunction (SLVD) receiving guideline-directed medical therapy (GDMT). We evaluated ICD utilization and efficacy in patients with DMD. Retrospective cohort study of DMD patients from 17 centers across North America between January 2, 2005 and December 31, 2015. ICD use and its effect on survival were evaluated in patients with SLVD defined as ejection fraction (EF) < 35% and/ or shortening fraction (SF) < 16% on final echocardiogram. SLVD was present in 57/436 (13.1%) patients, of which 12 (21.1%) died during the study period. Of these 12, (mean EF 20.9 ± 6.2% and SF 13.7 ± 7.2%), 8 received GDMT, 5 received steroids, and none received an ICD. ICDs were placed in 9/57 (15.8%) patients with SLVD (mean EF 31.2 ± 8.5% and SF 10.3 ± 4.9%) at a mean age of 20.4 ± 6.3 years; 8/9 received GDMT, 7 received steroids, and all were alive at study end; mean ICD duration was 36.1 ± 26.2 months. Nine ICDs were implanted at six different institutions, associated with two appropriate shocks for ventricular tachycardia in two patients, no inappropriate shocks, and one lead fracture. ICD use may be associated with improved survival and minimal complications in DMD cardiomyopathy with SLVD. However, inconsistent GDMT utilization may be a significant confounder. Future studies should define optimal indications for ICD implantation in patients with DMD cardiomyopathy.

Risk Factors for Cardiac and Non-cardiac Causes of Death in Males with Duchenne Muscular Dystrophy

As survival and neuromuscular function in Duchenne muscular dystrophy (DMD) have improved with glucocorticoid (GC) therapy and ventilatory support, cardiac deaths are increasing. Little is known about risk factors for cardiac and non-cardiac causes of death in DMD. A multi-center retrospective cohort study of 408 males with DMD, followed from January 1, 2005 to December 31, 2015, was conducted to identify risk factors for death. Those dying of cardiac causes were compared to those dying of non-cardiac causes and to those alive at study end. There were 29 (7.1%) deaths at a median age of 19.5 (IQR: 16.9-24.6) years; 8 (27.6%) cardiac, and 21 non-cardiac. Those living were younger [14.9 (IQR: 11.0-19.1) years] than those dying of cardiac [18 (IQR 15.5-24) years, p = 0.03] and non-cardiac [19 (IQR: 16.5-23) years, p = 0.002] causes. GC use was lower for those dying of cardiac causes compared to those living [2/8 (25%) vs. 304/378 (80.4%), p = 0.001]. Last ejection fraction prior to death/study end was lower for those dying of cardiac causes compared to those living (37.5% ± 12.8 vs. 54.5% ± 10.8, p = 0.01) but not compared to those dying of non-cardiac causes (37.5% ± 12.8 vs. 41.2% ± 19.3, p = 0.58). In a large DMD cohort, approximately 30% of deaths were cardiac. Lack of GC use was associated with cardiac causes of death, while systolic dysfunction was associated with death from any cause. Further work is needed to ensure guideline adherence and to define optimal management of systolic dysfunction in males with DMD with hopes of extending survival.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Use of advanced heart failure therapies in Duchenne muscular dystrophy

Background

As survival and neuromuscular function in Duchenne Muscular Dystrophy (DMD) improve with glucocorticoid therapy and respiratory advances, the proportion of cardiac deaths is increasing. Little is known about the use and outcomes of advanced heart failure (HF) therapies in this population.

Methods

A retrospective cohort study of 436 males with DMD was performed, from January 1, 2005-January 1, 2018, with the primary outcome being use of advanced HF therapies including: implantable cardioverter defibrillator (ICD), left ventricular assist device (LVAD), and heart transplantation (HTX).

Results

Nine subjects had an ICD placed, 2 of whom (22.2%) had appropriate shocks for ventricular tachycardia; 1 and 968 days after implant, and all of whom were alive at last follow-up; median 18 (IQR: 12.5-25.5) months from implant. Four subjects had a LVAD implanted with post-LVAD survival of 75% at 1 year; 2 remaining on support and 1 undergoing HTX. One subject was bridged to HTX with ICD and LVAD and was alive at last follow-up, 53 months after HTX.

Conclusion

Advanced HF therapies may be used effectively in select subjects with DMD. Further studies are needed to better understand risk stratification for ICD use and optimal candidacy for LVAD implantation and HTX, with hopes of improving cardiac outcomes.

Donor-recipient height ratio and outcomes in pediatric heart transplantation

Height matching in pediatric HTx has been proposed as a superior method of evaluating graft size, but no studies have examined survival advantage for height-matched donor-recipient pairs. We hypothesized that in pediatric patients with DCM, an oversized donor improves survival and aimed to define the optimal height ratio in this patient group. Pediatric primary HTx recipients with DCM between 10/89 and 09/12 were identified in the OPTN database. Patients were stratified into three donor-recipient height and weight ratio categories. One- and five-yr survival was compared using Kaplan-Meier analysis and HRs were computed. A total of 2133 children with DCM who underwent HTx during the study period were included. Unadjusted one-yr survival was worse for DRHR <0.87 (HR, 2.15 [95% CL, 1.30, 3.53]; p < 0.01). This difference was not present at five yr post-HTx or when stratified by weight. After adjustment for other risk factors affecting transplant survival, height matching was no longer significant. Although height matching appears to predict short-term survival better than weight in pediatric HTx recipients with DCM, other factors play a more important role as height matching loses significance in multivariate analysis.

Utility of Multimodality Imaging in the Morphologic Characterization of Anomalous Aortic Origin of a Coronary Artery

Background:

Anomalous aortic origin of a coronary artery from the wrong Sinus of Valsalva (AAOCA) is a rare congenital anomaly and is associated with sudden cardiac death. Morphologic features considered to be “high risk” are significant luminal narrowing, acute coronary angulation at its origin, intramural course, and long interarterial course. A consistent approach for characterization of these features is lacking.

Methods:

A retrospective single-center review of all patients diagnosed with AAOCA using echocardiogram and computed tomography (CT)/magnetic resonance imaging (MRI) studies was performed. Twenty-nine patients were identified (25 using CT and 4 using MRI) with subsequent three-dimensional data sets. The MRI data sets lacked adequate resolution and were excluded. Twenty-five patients (median age 15.1, range 10-39.5 years, 72% male) were further analyzed using echocardiogram and CT. Morphologic assessment focused on luminal stenosis, coronary angulation, and interarterial length. Additional morphologic features focusing on cross-sectional area and degree of ellipticity were also assessed.

Results:

Echocardiography tended to yield smaller measurements compared to CT and had poor interobserver reproducibility for measurements pertaining to the narrowest proximal and distal coronary segments. Computed tomography showed good inter-/intraobserver reproducibility for the same. Agreement between both modalities for coronary angulation at its origin was excellent. There was good agreement for measurements of interarterial length between echocardiography and CT, but echocardiography had superior reproducibility. Assessment of luminal cross-sectional area and elliptical shape by CT had excellent inter-/intraobserver reproducibility.

Conclusion:

The combination of echocardiography and CT characterizes morphologic features of anomalous origin of the coronary artery more reliably than either modality alone.

Pediatric cardiac retransplantation: Waitlist mortality stratified by age and era

BACKGROUND

Waitlist mortality among children listed for primary heart transplant (HTx) has been well characterized, whereas limited data exist for cardiac retransplantation (CRTx) after pediatric primary HTx. We sought to characterize the population listed for CRTx and to determine the factors that affect waitlist mortality.

METHODS

All individuals listed for CRTx >1 year after pediatric primary HTx between October 1, 1987, and October 14, 2012 were identified in the Organ Procurement and Transplantation Network database. Baseline characteristics and waitlist mortality were compared between age groups (< 11 years, 11-18 years, and > 18 years) and during 3 successive eras (1987-1999, 1999-2006, and 2006-2012).

RESULTS

The cohort comprised 632 patients who were listed for CRTx > 1 year after pediatric primary HTx. Median age was 4 years at primary HTx and 14 years at relisting. Median time from primary HTx to relisting was 7.3 years. Median waiting time was 75.3 days. Overall mortality was 25.2% (159 of 632). The most frequent relisting diagnosis was related to graft vasculopathy (62.5%). The leading causes of death were chronic rejection and vasculopathy (52%). Waitlist mortality significantly decreased after 2006 (31% vs 17%; p < 0.01), despite a relatively constant CRTx rate (67% vs 65%). Univariate analysis showed era, age, listing status, and life support (mechanical circulatory support device, extracorporeal membrane oxygenation, mechanical ventilation) were significant predictors of mortality. Multivariate analyses showed that later era (2006-2012), ages 11 to 18 years, and United Network of Organ Sharing listing status 2 predicted decreased mortality, whereas life support increased mortality.

CONCLUSIONS

Waitlist mortality for CRTx in children and young adults has decreased by almost 50% over time. Individuals relisted as adults have increased waitlist mortality.

Prognostic Value of Exercise Testing During Heart Transplant Evaluation in Children

Background—

Maximum oxygen consumption (peak VO 2 ) <50% predicted on exercise testing is a class I indication for heart transplant (HT) listing in children. This recommendation is based on exercise data in adults. We assessed the association of peak VO 2 <50% predicted during HT evaluation with freedom from death or deterioration in children.

Methods and Results—

We analyzed all children who underwent exercise testing during HT evaluation at our center between 2002 and 2011. Patients with peak VO 2 <50% predicted were compared with those with peak VO 2 ≥50% predicted for the composite outcome of death before HT, initiation of mechanical circulatory support, and HT at highest urgency status, using time-to-event analyses. There were 50 children in the study (median age, 15 years; interquartile range, 13–17 years; 24 girls; 18 with palliated single ventricle). Overall, 24 children reached the composite end point. Peak VO 2 <50% predicted was associated with outcome in children with biventricular circulation (hazard ratio, 4.7; 95% confidence interval, 1.8–12.3; P <0.001) but not in those with a palliated single ventricle (hazard ratio, 1.3; 95% confidence interval, 0.1–12.0; P =0.80). Similarly, VE/VCO 2 slope ≥34 was associated with outcome in children with biventricular circulation (hazard ratio, 2.7; 95% confidence interval, 1.1–7.1; P <0.001) but not in children with a palliated single ventricle.

Conclusions—

Exercise testing during HT evaluation in children with biventricular circulation identified those at higher risk of death or deterioration in this small study. Larger studies are needed to assess the role of exercise testing during HT evaluation in children with a palliated single ventricle.

Normal Values of Left Atrial Volume in Pediatric Age Group Using a Validated Allometric Model

Background—

Left atrial volume (LAV) increase is an indicator of diastolic dysfunction and a surrogate marker of significant left to right shunts. Normalization of LAV is currently performed by indexing to body surface area 1 (BSA 1 ). The indexed LAV thus derived does not account for the nonlinear relationship of physiologic variables to BSA and has not been tested for independence to body size. Our objective was to identify a valid allometric model for indexing LAV and use it to develop Z-scores in children.

Methods and Results—

LAV was measured in 300 normal subjects by echocardiography using the biplane area length method. LAV/BSA 1 had a residual relationship to BSA (r=0.52, P <0.0001). The allometric exponent (AE) derived for the entire cohort (1.27) using the least squares regression analysis also failed to eliminate the residual relationship to BSA (r=−0.15, P =0.01). Dividing the cohort in two groups with a BSA cut-off of 1 m 2 provided the best-fit allometric model. The AE for each group was 1.48 and 1.08 for BSA≤1 m 2 and >1 m 2 , respectively, and was validated against an independent sample. The mean indexed LAV±SD for BSA≤1 m 2 and >1 m 2 is 31.5±5.5 mL and 26.0±4.2 mL, respectively, and was used to derive Z-scores.

Conclusions—

This study demonstrates the fallacy of using “per-BSA 1 standards” for normalization of LAV in pediatrics. LAV/BSA 1.48 for children with BSA≤1 m 2 and LAV/BSA 1.08 for those with BSA>1 m 2 is accurate and can be used to derive Z-scores.

Impact of age at fontan completion on functional status at mid-term follow up

INTRODUCTION

Although the Fontan palliation is now being applied to younger patients, the influence of patients' age at the time of surgery on mid- and long-term results remains unclear. It has been our policy to perform Fontan operations when patients are around 5 years old in order to fit a larger conduit and minimize the risk of later obstruction. We sought to investigate whether age at Fontan completion affects subsequent clinical status in patients followed up for more than 3 years.

METHODS

We carried out a cross-sectional study of Fontan patients who underwent total cavopulmonary connection between 1997 and 2009 and were followed up for 3 years with detailed chart review, ECG, echocardiogram, and functional status questionnaire.

RESULTS

Of the total of 58 patients there were 56 long-term survivors. Of these, 41 had undergone surgery 3 years prior to the time of the study. We were able to contact 37 patients, who comprised our study cohort (mean follow up 6.3, range 3.0-11.0 years). Mean age at operation was 7.4 years (median 5.5, range 3.0-29.5 years). At latest follow up, 97% were in NYHA class I or II. In terms of somatic development, 21% (8/37) for weight and 19% (7/37) for height were below the 25th percentile for age-matched controls. Excluding one patient with developmental delay due to an underlying syndrome, there were 5 patients (13.5%) with mild learning disabilities and one with moderate delays. No additional surgeries had been performed. Tissue Doppler imaging measurements of systolic and diastolic velocities of the lateral annulus of the dominant ventricle revealed abnormalities of both systolic function and diastolic compliance, although qualitatively the systolic function of the single ventricle was considered adequate in all patients.

CONCLUSIONS

Although earlier Fontan palliation is considered beneficial in the long term from the viewpoint of exercise capacity and hemodynamics, even late Fontan completion provides acceptable mid-term results in terms of the patients' functional status.

Emergency transmediastinal pneumonectomy for scimitar syndrome

Repair of scimitar syndrome presenting in infancy involves either tunneling or reimplantation of the anomalous vein to the left atrium and may be fraught with serious complications such as thrombosis and secondary pulmonary infarction necessitating pneumonectomy. The authors present the case of a severely symptomatic infant with scimitar syndrome, managed initially with closure of an atrial septal defect in the hope of avoiding a repair with considerable risk of scimitar vein thrombosis and pulmonary infarction. Despite initial clinical improvement, subsequent rapid development of spontaneous massive emphysematous degeneration of the right lung necessitated emergency pneumonectomy, which was accomplished via the median sternotomy approach.

The fontan procedure in Greece: early surgical results and excellent mid-term outcome

INTRODUCTION

The Fontan operation (modified from its original version) affords excellent palliation for many patients with various forms of anatomic or functional single ventricle. The purpose of this study was to evaluate the outcome of our experience with the Fontan procedure in Greece.

METHODS

Fifty-eight consecutive patients with single ventricle physiology had a modified Fontan operation between 1997 and 2009. Their records were reviewed retrospectively. Follow up, which included clinical evaluation and echocardiographic functional assessment, was complete.

RESULTS

Median age at operation was 5.7 years (range 3 years to 29.4 years); 46.5% had multistage palliation (stage I and II); 79% had prior bidirectional cavopulmonary shunt (stage II) and 8.6% single stage Fontan. Fifty-four patients had an extracardiac conduit total cavopulmonary connection (EC-TCPC) and 4 an intra-atrial lateral tunnel (LT-TCPC). Fenestration was performed in 26 (44.8%) patients. Operative mortality was 0%. One patient required a short period of extracorporeal membrane oxygenator support. The most frequent complication was prolonged pleural effusion. Median duration of pleural effusion was 17 days (range 6-47 days). Median duration of follow up was 5.44 years (range 0.36 to 11.5 years). There were 2 late deaths (overall mortality 3.4%). One patient died from progressive deterioration of ventricular function within 2 years of operation and the other from fulminant endocarditis. Ten subjects have undergone device closure of a persistent fenestration. All 56 surviving patients are in excellent clinical condition (NYHA class I or II).

CONCLUSIONS

We have performed the Fontan procedure over a period of 13 years in Greece with excellent mid- and long-term results. Longer follow up will be necessary to assess the possible incidence of late severe complications, some of which may necessitate heart transplantation.

Atresia of the superior vena cava causing cyanosis and increasing head circumference in an infant

We report a case of congenital atresia of the superior vena cava (SVC) with stenotic anastomoses between systemic and pulmonary veins, resulting in cyanosis and symptoms consistent with SVC syndrome in an infant.

Anterior aortic reimplantation of anomalous left coronary artery from the pulmonary artery (ALCAPA) originating from the nonfacing sinus in an adult

We report successful repair of a rare type of anomalous origin left main coronary artery from the nonfacing pulmonary artery sinus in an adult patient presenting with cardiac arrest as first symptom. Intraoperative findings and surgical technique are discussed.

A comparison of echocardiographic techniques in determination of arterial elasticity in the pediatric population

BACKGROUND

Many methods are used to measure arterial elasticity in children using echocardiography. There is no data to support the equivalence of the different techniques. The goal of this study was to evaluate the reproducibility of several techniques used to measure arterial elasticity using echocardiography.

METHODS

Aortic distension in two different sites (arterial distension) through the cardiac cycle was measured by (four) two-dimensional (2D) and M-mode echocardiographic techniques in 20 children without significant structural heart disease. These measurements combined with noninvasive blood pressure measurements were used to calculate arterial elastic indices. Arterial elasticity was expressed in terms of distensibility and stiffness. Data were collected by two sonographers and interpreted by two reviewers. Paired Student's t-test and Pitman's test for equality of variance for correlated observations were used to detect differences between different sonographers, different reviewers, and different techniques.

RESULTS

No significant difference in the measured elasticity between sonographers or reviewers was observed. There was a somewhat increased variance in two of the four techniques evaluated. There was no significant difference in elasticity measured using different techniques to evaluate the same arterial site, although a significantly decreased elasticity was noted from measurements taken in the proximal ascending aorta as compared with the distal ascending aorta.

CONCLUSIONS

Many echocardiographic techniques produce reproducible measurements of arterial elasticity. There may be intrinsic differences in arterial elasticity between different segments of the ascending aorta, which have not been previously described in children with normal cardiac anatomy. Comparisons of data from separate studies must take these differences into account.

Relation of coarctation of the aorta to the occurrence of ascending aortic dilation in children and young adults with bicuspid aortic valves

Children with bicuspid aortic valve (BAV) have aortic dilation that is present and progressive from birth irrespective of the functional state of the valve. There are no published data comparing aortic dilation in children with BAV with and without aortic coarctation (CoA). The objectives of this study were to (1) compare differences in aortic dimensions and rates of dilation between children with isolated BAV with those of children with BAV and CoA and (2) identify risk factors for the development of aortic dilation. Patients with BAV with CoA (group A) and without CoA (group B) were identified from our echocardiographic database (1993 to 2006). Aortic measurements at 4 levels were obtained, and z scores were compared. Criteria for exclusion were severe aortic regurgitation/stenosis, previous aortic valvuloplasty, complex left-sided cardiac disease, ventricular septal defects, and Turner, Noonan, Williams, and Marfan syndromes. There were 600 echocardiograms in 247 patients. Group A had 192 echocardiograms in 53 patients (median age 11.3 years; range 0 to 30; median follow-up 7 years), and group B had 382 in 194 patients (median age 8.7 years; range 0 to 29; median follow-up 4 years). Group B had significantly greater ascending aorta dimensions (p<0.05) and significantly faster rates of aortic dilation (p<0.0001). The ascending aorta in patients with BAV and CoA did not dilate to the same degree as in patients with isolated BAV. In conclusion, valve morphologic characteristics and function and age at CoA repair had none to minimal impact on aortic dimensions.

Electrocardiographic predictors of left ventricular hypertrophy in pediatric hypertension

OBJECTIVE

To determine the efficacy of electrocardiography (ECG) in detecting left ventricular hypertrophy (LVH) in pediatric hypertension (HT).

STUDY DESIGN

Concomitant echocardiograms and electrocardiograms in 108 children with HT were reviewed. Left ventricular mass (LVM), assessed by echocardiography, was used as a basis for a diagnosis of LVH (echo LVH) using accepted pediatric criteria. Using Wilcoxon's rank-sum test, 14 ECG variables were compared between subjects with and without echo LVH. Spearman correlations were used to examine the linear association between echo LVH and these ECG variables. The sensitivity and specificity of ECG in diagnosing LVH were computed.

RESULTS

Of the 108 subjects studied, 35 (32%) met the pediatric criteria for LVH; of these, 8 (7.4%) also met the adult criteria (>51 g/m(2.7)) for LVH. Mean values for only 5 ECG criteria differed significantly among the groups: RI, SaVR, RaVL, RI+SIII, and SVI+RV6 (P < .05). Significant correlations were found for several ECG criteria and at least 1 measure of LVM, but the magnitudes were modest. Standard ECG criteria predicted LVH with high specificity (>90%) but low sensitivity (<35%). RI >10 mm was identified as demonstrating a modestly improved positive likelihood ratio of approximately 3.

CONCLUSIONS

ECG is not an adequate predictor of LVH for clinical use in HT.

Echocardiographic evaluation and surgical implications of common atrioventricular canal defects with absent or diminutive ostium primum defect

Common atrioventricular canal defects without ostium primum defects are rare, and their accurate identification has important surgical implications. Retrospective echocardiographic database review identified subjects with common atrioventricular canal defects with absent or diminutive ostium primum defects. Surgical reports and initial and postoperative echocardiograms were reviewed to identify the imaging planes necessary to characterize this anomaly and the surgical challenges imposed by the diagnosis. Fourteen subjects were identified (93% with trisomy 21) with either absent (n = 6) or diminutive (n = 8) ostium primum defects. Malaligned conal septum was present in 50% of subjects with absent primum defects and 12.5% of subjects with diminutive defects. Immediate or long-term complications of the 11 postoperative patients included atrioventricular block (n = 4) and moderate (n = 5) or severe (n = 3) mitral regurgitation. In conclusion, echocardiographic features for the identification of common atrioventricular canal defects with absent or diminutive ostium primum defects are described. Surgical challenges involve attaining adequate exposure of the mitral component and achieving mitral valve competence.

Frequency of aberrant subclavian artery, arch laterality, and associated intracardiac anomalies detected by echocardiography

Tetralogy of Fallot is generally considered to be the most common congenital heart defect associated with an aberrant subclavian artery (ASA), but the prevalence of ASA in patients with other cardiac anomalies is not well described. The pediatric echocardiography database, with 15,871 initial echocardiograms, was searched for all patients with ASA. Arch laterality and associated intracardiac anomalies were documented for each patient. ASA was found in 226 patients, of whom 171 had a left aortic arch (LAA) and 55 had a right aortic arch (RAA). The occurrence of ASA was 1% in patients with LAA (171 of 15,650) and 25% in patients with RAA (55 of 221; p = 0.001). Intracardiac anatomy was normal in 32% of patients with ASA/LAA and 25% with ASA/RAA. Conotruncal anomalies occurred more frequently with ASA/RAA than ASA/LAA (36% vs 18%; p = 0.01). Atrioventricular canal defects accounted for 10% and left-sided cardiac obstructive lesions accounted for 11% of subjects with ASA/LAA. ASA was rarely associated with d-transposition of the great arteries (1 of 226) and double-outlet right ventricle (5 of 226). The prevalence of ASA was highest in patients with interrupted aortic arch (11 of 38; 29%). In patients with tetralogy of Fallot, the overall prevalence of ASA was 8% (34 of 447), but was higher with RAA (16 of 103; 16%). The highest prevalence of ASA occurred in the subgroup of patients with tetralogy of Fallot with pulmonary atresia and RAA (6 of 25; 24%). In conclusion, ASA was more common in patients with RAA, especially with conotruncal anomalies. In patients with LAA, hypoplastic left heart syndrome, aortic coarctation, and atrioventricular canal defects were commonly associated with ASA.

Echocardiographic diagnosis of clinically silent congenital coronary artery anomalies

BACKGROUND

The incidence of congenital coronary anomalies is mainly derived from autopsy series and pre-participation exams in athletes. Limited data exist regarding the spectrum of coronary anomalies that can be detected in asymptomatic patients. We sought to describe echocardiographically detected congenital coronary artery anomalies in asymptomatic children after implementing a screening protocol mandating identification of coronary artery origin and proximal course in all initial studies.

METHODS

Our database was searched from 1/1/1993 to 3/31/2006 and all echocardiograms coded for coronary anomalies were identified. Clinically "silent" congenital coronary anomalies were culled from that group.

RESULTS

Of the 168 "silent" coronary anomalies detected, 111 were anomalies of aortic origin, including 59 patients with "high coronary takeoff" and 30 patients with "wrong sinus" origin of either the left or right coronary artery. Small coronary fistulas were seen in 57. Associated congenital heart defects were found in 53% of individuals with coronary anomalies.

CONCLUSIONS

This study comprises the largest group of echocardiographically detected, "silent" but potentially clinically significant, congenital coronary anomalies in children. Prospective echocardiographic diagnosis of "high coronary takeoff", a risk factor for injury during cardio-pulmonary bypass, and asymptomatic intraseptal coronary stenosis are described for the first time.

Acute myopericarditis after multiple vaccinations in an adolescent: case report and review of the literature

We report a case of postvaccination acute myopericarditis in an adolescent. The patient presented with acute chest pain, diffuse ST-segment elevation, and elevated cardiac enzyme levels. Cardiac MRI was consistent with acute myocarditis. He recovered within a few days with nonsteroidal antiinflammatory treatment and remains clinically stable, with improvement of MRI findings at the 10-week follow-up. Postvaccination cases of myopericarditis reported in the pediatric literature are also reviewed.

Regression of left ventricular hypertrophy in children with antihypertensive therapy

Left ventricular hypertrophy (LVH) is a complication of hypertension that has received great attention in the adult population. Large-scale randomized control studies in adults have demonstrated that LVH regresses in response to pharmacologic intervention. While it is known that LVH occurs as a complication of hypertension in the pediatric population, few studies have focused on its regression with pharmacological intervention. We report on three cases of hypertension-induced LVH in the pediatric population and its regression after treatment with antihypertensive medications. This report brings to light the need for larger, prospective studies on the incidence, natural history, and treatment of LVH associated with hypertension in the pediatric population.

Ascending aortic aneurysm in a fetus due to a benign nodular myofibroblastic lesion

A fetal echocardiogram at 20 weeks of gestation revealed a large ascending aortic aneurysm in the presence of a normal aortic root and normal intracardiac anatomy. No other abnormalities were noted in the fetus. Upon termination of pregnancy, histopathological examination revealed an isolated benign nodular myofibroblastic lesion of likely hamartomatous origin, a first description of such pathology contributing to the formation of an aneurysm in the ascending aorta.

Color Doppler Tissue Imaging for Evaluation of Right Ventricular Systolic Function in Patients with Congenital Heart Disease

OBJECTIVE

We sought to explore the relationship of color Doppler tissue imaging-derived systolic indices of tricuspid valve annular motion and magnetic resonance imaging-derived right ventricular (RV) ejection fraction in patients with congenital heart disease.

METHODS

Patients with congenital heart disease who underwent echocardiography and magnetic resonance imaging on the same day were included. The tricuspid valve annular color Doppler tissue imaging-derived parameters of peak velocity during isovolumic contraction, myocardial acceleration during isovolumic contraction, peak systolic velocity, and Tei index were compared with magnetic resonance imaging-derived RV ejection fraction.

RESULTS

Peak systolic velocity and myocardial acceleration during isovolumic contraction correlated well with RV ejection fraction after adjusting for age, RV dilation, and pressure overload (r = 0.65 and 0.73, respectively). Interobserver and intraobserver reliability were excellent for peak systolic velocity (r = 0.95 and 0.97, respectively) and very good for myocardial acceleration during isovolumic contraction (r = 0.93 and 0.85, respectively).

CONCLUSIONS

Color Doppler tissue imaging indices of tricuspid valve annular motion are reproducible and provide a potentially useful complementary tool for assessment of RV systolic function in patients with congenital heart disease.

Regional differences in right ventricular systolic function as determined by cine magnetic resonance imaging after infundibulotomy

The right ventricle of subjects after infundibulotomy (n = 20) and of subjects free of right ventricular disease (n = 19) was partitioned into the infundibular and sinus segments to examine the relative size and function of each. Excellent agreement was found between observers for measuring regional volume and ejection fraction. Although the surgical subjects had lower infundibular ejection fraction and higher indexed volumes, most had preserved sinus ejection fraction.