Design and implementation of multicenter pediatric and congenital studies with cardiovascular magnetic resonance: Big data in smaller bodies.

Cardiovascular magnetic resonance (CMR) has become the reference standard for quantitative and qualitative assessment of ventricular function, blood flow, and myocardial tissue characterization. There is a preponderance of large CMR studies and registries in adults; However, similarly powered studies are lacking for the pediatric and congenital heart disease (PCHD) population. To date, most CMR studies in children are limited to small single or multicenter studies, thereby limiting the conclusions that can be drawn. Within the PCHD CMR community, a collaborative effort has been successfully employed to recognize knowledge gaps with the aim to embolden the development and initiation of high-quality, large-scale multicenter research. In this publication, we highlight the underlying challenges and provide a practical guide toward the development of larger, multicenter initiatives focusing on PCHD populations, which can serve as a model for future multicenter efforts.

Effects of Implementing a Standardized Surveillance Program on Cardiac Neurodevelopmental Program Referral Completion.

Differences in surveillance methods have resulted in significant variability in referral volumes and referral completion rates across cardiac neurodevelopmental programs, with frequent barriers to referral completion including high no-show rates, lack of education, and inaccessibility for underrepresented populations. The purpose of this study was to describe implementation of a standardized surveillance program and investigate impact on referral volume and completion over a two-year period. Between fiscal years 2021 and 2022, a surveillance program was implemented which standardized assessment of neurodevelopmental risk via a checklist as well as family education and referral procedures. All patients referred to the cardiac neurodevelopmental program during these two fiscal years were included in the analysis, and patient referrals were categorized as complete or incomplete (due to physician-related or patient-related factors). Referral completion rates between fiscal years were compared using two sample Z test of proportions, while associations between referral completion and demographic/anatomical variables were completed using chi-square tests of independence. Implementation of the formal surveillance program resulted in a 66.7% increase in referral volume. Proportions of both incomplete referrals (z = 2.00, p < 0.05) and incomplete referrals due to physician-related factors (z = 4.34, p < 0.01) were significantly lower after implementation. A significant association was found after implementation between referral completion and race/ethnicity (x2 = 14.08, p < 0.01) due to a significantly high proportion of completed referrals for patients identifying as Hispanic/Latino within the overall distribution of patients. This study describes the successful implementation of a standardized surveillance program, including improvements to referral volume and completion rate. Findings also support implementation of methods that emphasize physician surveillance methods and improve accessibility for historically marginalized groups at greatest risk for disparities in access and quality of care.

SCMR expert consensus statement for cardiovascular magnetic resonance of acquired and non-structural pediatric heart disease.

Cardiovascular magnetic resonance (CMR) is widely used for diagnostic imaging in the pediatric population. In addition to structural congenital heart disease (CHD), for which published guidelines are available, CMR is also performed for non-structural pediatric heart disease, for which guidelines are not available. This article provides guidelines for the performance and reporting of CMR in the pediatric population for non-structural ("non-congenital") heart disease, including cardiomyopathies, myocarditis, Kawasaki disease and systemic vasculitides, cardiac tumors, pericardial disease, pulmonary hypertension, heart transplant, and aortopathies. Given important differences in disease pathophysiology and clinical manifestations as well as unique technical challenges related to body size, heart rate, and sedation needs, these guidelines focus on optimization of the CMR examination in infants and children compared to adults. Disease states are discussed, including the goals of CMR examination, disease-specific protocols, and limitations and pitfalls, as well as newer techniques that remain under development.

Fenfluramine hydrochloride for the treatment of seizures in Dravet syndrome: a randomised, double-blind, placebo-controlled trial.

BACKGROUND: Dravet syndrome is a rare, treatment-resistant developmental epileptic encephalopathy characterised by multiple types of frequent, disabling seizures. Fenfluramine has been reported to have antiseizure activity in observational studies of photosensitive epilepsy and Dravet syndrome. The aim of the present study was to assess the efficacy and safety of fenfluramine in patients with Dravet syndrome. METHODS: In this randomised, double-blind, placebo-controlled clinical trial, we enrolled children and young adults with Dravet syndrome. After a 6-week observation period to establish baseline monthly convulsive seizure frequency (MCSF; convulsive seizures were defined as hemiclonic, tonic, clonic, tonic-atonic, generalised tonic-clonic, and focal with clearly observable motor signs), patients were randomly assigned through an interactive web response system in a 1:1:1 ratio to placebo, fenfluramine 0·2 mg/kg per day, or fenfluramine 0·7 mg/kg per day, added to existing antiepileptic agents for 14 weeks. The primary outcome was the change in mean monthly frequency of convulsive seizures during the treatment period compared with baseline in the 0·7 mg/kg per day group versus placebo; 0·2 mg/kg per day versus placebo was assessed as a key secondary outcome. Analysis was by modified intention to treat. Safety analyses included all participants who received at least one dose of study medication. This trial is registered with ClinicalTrials.gov with two identical protocols NCT02682927 and NCT02826863. FINDINGS: Between Jan 15, 2016, and Aug 14, 2017, we assessed 173 patients, of whom 119 patients (mean age 9·0 years, 64 [54%] male) were randomly assigned to receive either fenfluramine 0·2 mg/kg per day (39), fenfluramine 0·7 mg/kg per day (40) or placebo (40). During treatment, the median reduction in seizure frequency was 74·9% in the fenfluramine 0·7 mg/kg group (from median 20·7 seizures per 28 days to 4·7 seizures per 28 days), 42·3% in the fenfluramine 0·2 mg/kg group (from median 17·5 seizures per 28 days to 12·6 per 28 days), and 19·2% in the placebo group (from median 27·3 per 28 days to 22·0 per 28 days). The study met its primary efficacy endpoint, with fenfluramine 0·7 mg/kg per day showing a 62·3% greater reduction in mean MCSF compared with placebo (95% CI 47·7-72·8, p<0·0001); fenfluramine 0·2 mg/kg per day showed a 32·4% reduction in mean MCSF compared with placebo (95% CI 6·2-52·3, p=0·0209). The most common adverse events (occurring in at least 10% of patients and more frequently in the fenfluramine groups) were decreased appetite, diarrhoea, fatigue, lethargy, somnolence, and decreased weight. Echocardiographic examinations revealed valve function within the normal physiological range in all patients during the trial and no signs of pulmonary arterial hypertension. INTERPRETATION: In Dravet syndrome, fenfluramine provided significantly greater reduction in convulsive seizure frequency compared with placebo and was generally well tolerated, with no observed valvular heart disease or pulmonary arterial hypertension. Fenfluramine could be an important new treatment option for patients with Dravet syndrome. FUNDING: Zogenix.

Cardiovascular safety of fenfluramine in the treatment of Dravet syndrome: Analysis of an ongoing long-term open-label safety extension study.

OBJECTIVE: Fenfluramine, which was previously approved as a weight loss drug, was withdrawn in 1997 when reports of cardiac valvulopathy emerged. The present study was conducted in part to characterize the cardiovascular safety profile of low-dose fenfluramine when used in a pediatric population to reduce seizure frequency in patients with Dravet syndrome. METHODS: Patients 2- to 18-years-old with Dravet syndrome who had completed any of three randomized, placebo-controlled clinical trials of fenfluramine were offered enrollment in this open-label extension (OLE) study. All patients were treated with fenfluramine starting at a dose of 0.2 mg/kg/day (oral solution dosed twice per day), which was titrated to maximal effect with a dose limit of 0.7 mg/kg/day (maximum 26 mg/day) or 0.4 mg/kg/day (maximum 17 mg/day) in patients receiving concomitant stiripentol. Standardized echocardiographic examinations were conducted at Week 4 or 6 and then every 3 months during the OLE study to monitor cardiac valve function and structure and pulmonary artery pressure. The primary end point for the echocardiography analysis was the number of patients who developed valvular heart disease or pulmonary artery hypertension (PAH) during treatment. RESULTS: A total of 232 patients were enrolled in the study. The average age of patients was 9.1 ± 4.7 years, and 55.2% were male. The median duration of treatment with fenfluramine was 256 days (range = 58-634 days), and the mean dose of fenfluramine was 0.41 mg/kg/day. No cases of valvular heart disease or PAH were observed. SIGNIFICANCE: Longitudinal echocardiography over a median 8.4 months of treatment with fenfluramine suggests a low risk of developing cardiac valvulopathy and PAH when used to treat pediatric patients with Dravet syndrome.

Evaluation of self-calibrated non-linear phase-contrast correction in pediatric and congenital cardiovascular magnetic resonance imaging.

BACKGROUND: The need for background error correction in phase-contrast flow analysis has historically posed a challenge in cardiac magnetic resonance (MR) imaging. While previous studies have shown that phantom correction improves flow measurements, it impedes scanner workflow. OBJECTIVE: To evaluate the efficacy of self-calibrated non-linear phase-contrast correction on flows in pediatric and congenital cardiac MR compared to phantom correction as the standard. MATERIALS AND METHODS: We retrospectively identified children who had great-vessel phase-contrast and static phantom sequences acquired between January 2015 and June 2015. We applied a novel correction method to each phase-contrast sequence post hoc. Uncorrected, non-linear, and phantom-corrected flows were compared using intraclass correlation. We used paired t-tests to compare how closely non-linear and uncorrected flows approximated phantom-corrected flows. In children without intra- or extracardiac shunts or significant semilunar valvular regurgitation, we used paired t-tests to compare how closely the uncorrected pulmonary-to-systemic flow ratio (Qp:Qs) and non-linear Qp:Qs approximated phantom-corrected Qp:Qs. RESULTS: We included 211 diagnostic-quality phase-contrast sequences (93 aorta, 74 main pulmonary artery [MPA], 21 left pulmonary artery [LPA], 23 right pulmonary artery [RPA]) from 108 children (median age 15 years, interquartile range 11-18 years). Intraclass correlation showed strong agreement between non-linear and phantom-corrected flow measurements but also between uncorrected and phantom-corrected flow measurements. Non-linear flow measurements did not more closely approximate phantom-corrected measurements than did uncorrected measurements for any vessel. In 39 children without significant shunting or regurgitation, mean non-linear Qp:Qs (1.07; 95% confidence interval [CI] = 1.01, 1.13) was no closer than mean uncorrected Qp:Qs (1.06; 95% CI = 1.00, 1.13) to mean phantom-corrected Qp:Qs (1.02; 95% CI = 0.98, 1.06). CONCLUSION: Despite strong agreement between self-calibrated non-linear and phantom correction, cardiac flows and shunt calculations with non-linear correction were no closer to phantom-corrected measurements than those without background correction. However, phantom-corrected flows also demonstrated minimal differences from uncorrected flows. These findings suggest that in the current era, more accurate phase-contrast flow measurements might limit the need for background correction. Further investigation of the clinical impact and optimal methods of background correction in the pediatric and congenital cardiac population is needed.

Predictors of Rapid Aortic Root Dilation and Referral for Aortic Surgery in Marfan Syndrome.

Few data exist regarding predictors of rapid aortic root dilation and referral for aortic surgery in Marfan syndrome (MFS). To identify independent predictors of the rate of aortic root (AoR) dilation and referral for aortic surgery, we investigated the data from the Pediatric Heart Network randomized trial of atenolol versus losartan in young patients with MFS. Data were analyzed from the echocardiograms at 0, 12, 24, and 36 months read in the core laboratory of 608 trial subjects, aged 6 months to 25 years, who met original Ghent criteria and had an AoR z-score (AoRz) > 3. Repeated measures linear and logistic regressions were used to determine multivariable predictors of AoR dilation. Receiver operator characteristic curves were used to determine cut-points in AoR dilation predicting referral for aortic surgery. Multivariable analysis showed rapid AoR dilation as defined by change in AoRz/year > 90th percentile was associated with older age, higher sinotubular junction z-score, and atenolol use (R2 = 0.01) or by change in AoR diameter (AoRd)/year > 90th percentile with higher sinotubular junction z-score and non-white race (R2 = 0.02). Referral for aortic root surgery was associated with higher AoRd, higher ascending aorta z-score, and higher sinotubular junction diameter:ascending aorta diameter ratio (R2 = 0.17). Change in AoRz of 0.72 SD units/year had 42% sensitivity and 92% specificity and change in AoRd of 0.34 cm/year had 38% sensitivity and 95% specificity for predicting referral for aortic surgery. In this cohort of young patients with MFS, no new robust predictors of rapid AoR dilation or referral for aortic root surgery were identified. Further investigation may determine whether generalized proximal aortic dilation and effacement of the sinotubular junction will allow for better risk stratification. Rate of AoR dilation cut-points had high specificity, but low sensitivity for predicting referral for aortic surgery, limiting their clinical use. Clinical Trial Number ClinicalTrials.gov number, NCT00429364.

Atenolol versus losartan in children and young adults with Marfan's syndrome.

BACKGROUND: Aortic-root dissection is the leading cause of death in Marfan's syndrome. Studies suggest that with regard to slowing aortic-root enlargement, losartan may be more effective than beta-blockers, the current standard therapy in most centers. METHODS: We conducted a randomized trial comparing losartan with atenolol in children and young adults with Marfan's syndrome. The primary outcome was the rate of aortic-root enlargement, expressed as the change in the maximum aortic-root-diameter z score indexed to body-surface area (hereafter, aortic-root z score) over a 3-year period. Secondary outcomes included the rate of change in the absolute diameter of the aortic root; the rate of change in aortic regurgitation; the time to aortic dissection, aortic-root surgery, or death; somatic growth; and the incidence of adverse events. RESULTS: From January 2007 through February 2011, a total of 21 clinical centers enrolled 608 participants, 6 months to 25 years of age (mean [±SD] age, 11.5±6.5 years in the atenolol group and 11.0±6.2 years in the losartan group), who had an aortic-root z score greater than 3.0. The baseline-adjusted rate of change in the mean (±SE) aortic-root z score did not differ significantly between the atenolol group and the losartan group (-0.139±0.013 and -0.107±0.013 standard-deviation units per year, respectively; P=0.08). Both slopes were significantly less than zero, indicating a decrease in the aortic-root diameter relative to body-surface area with either treatment. The 3-year rates of aortic-root surgery, aortic dissection, death, and a composite of these events did not differ significantly between the two treatment groups. CONCLUSIONS: Among children and young adults with Marfan's syndrome who were randomly assigned to losartan or atenolol, we found no significant difference in the rate of aortic-root dilatation between the two treatment groups over a 3-year period. (Funded by the National Heart, Lung, and Blood Institute and others; ClinicalTrials.gov number, NCT00429364.).

Application of the Pediatric Appropriate Use Criteria for Chest Pain.

OBJECTIVES: To characterize the subgroup of outpatient pediatric patients presenting with chest pain and to determine the effectiveness of published pediatric appropriate use criteria (PAUC) to detect pathology. STUDY DESIGN: The Pediatric Appropriate Use of Echocardiography study evaluated the use and yield of transthoracic echocardiography (TTE) before and after PAUC release. Data were reviewed on patients ?18 years of age who underwent TTE for chest pain. Indications were classified as appropriate (A), may be appropriate (M), and rarely appropriate (R) based on PAUC ratings, and findings were normal, incidental, or abnormal. RESULTS: Chest pain was the primary indication in 772 of 4562 outpatient TTE studies (17%) (median age 14 years, IQR 10-16) ordered during the study period: 458 of 772 before (59%) and 314 of 772 after (41 %) the release of PAUC with no change in appropriateness. In A indications (n?=?654), 642 (98%) were normal, 5 (1%) had incidental findings, and 7 (1%) were abnormal. A and M detected 100% of all abnormal findings (A: n?=?7; M: n?=?6; R: n?=?0), with an association between ratings and findings (P?<.001). There was no association between R rating and any pathology. CONCLUSIONS: There was no change in ordering patterns with publication of the PAUC. Despite the high rate of TTEs ordered for indications rated A, most studies were normal. Studies that detected pathology were performed for indications rated A or M, but not R. This study supports PAUC as a useful tool in pediatric chest pain evaluation that may subsequently improve the use of TTE.

Assessment of Growth 6 Years after the Norwood Procedure.

At 6 years of age, patients with hypoplastic left heart syndrome had mean age-adjusted z-scores for weight and height below the normative population, and body mass index was similar to the normative population. Males had the greatest increase in z-scores for body mass index. TRIAL REGISTRATION: ClinicalTrials.gov: NCT00115934.

Application of pediatric appropriate use criteria for initial outpatient evaluation of syncope.

BACKGROUND: Syncope is a common reason for outpatient transthoracic echocardiography (TTE). We studied the applicability of pediatric appropriate use criteria (AUC) on initial outpatient evaluation of children (≤18 years) with syncope. METHODS: Data were obtained before (Phase I, April-September 2014) and after (Phase II, January-April 2015) the release of the AUC document from six participating pediatric cardiology centers. Site investigators determined the indication for TTE and assigned appropriateness rating based on the AUC document: Appropriate (A), May Be Appropriate (M), Rarely Appropriate (R), or "unclassifiable" (U) if it did not fit any scenario in the AUC document. RESULTS: Of the total 4562 TTEs, 310 (6.8%) were performed for syncope: 174/2655 (6.6%) Phase I and 136/1907 (7.1%) Phase II, P=.44. Overall, 168 (50.5%) were for indications rated A, 63 (18.9%) for M, 79 (23.7%) for R, and 23 (6.9%) for U. Release of AUC did not change the appropriateness of TTEs [A=51.6% vs 49.0%, P=.63, R=20.2% vs 28.3%, P=.09]. Overall syncope-related R indications formed 15.7% of R indications for all the echocardiograms performed in the entire Pediatric Appropriate Use (PAUSE) study (11.9% Phase I and 22.4% Phase II, P=.002). TTEs were normal in majority of the patients except 7 that had incidental findings. CONCLUSIONS: In conclusion, syncope is a common reason for indications rated R and release of the AUC document did not improve appropriate utilization of TTE in syncope. Targeted educational interventions are needed to reduce unnecessary TTEs in children with syncope.

Comparison of Echocardiographic Diagnostic Criteria of Left Ventricular Noncompaction in a Pediatric Population.

BACKGROUND: There is controversy regarding the best echocardiographic diagnostic criteria for left ventricular noncompaction (LVNC). We assessed the diagnostic utility and reproducibility of the previously proposed echocardiographic diagnostic criteria in a pediatric population using a segmental approach. METHODS: Echocardiograms were matched for patients with and without a clinical diagnosis of LVNC. Blinded reviews of echocardiograms measured (1) depths of intertrabecular recesses (X/Y), (2) noncompaction-to-compaction ratio (NC/C), and (3) number of trabeculations, using a segmental approach. Measurements were analyzed for area under the receiver operating characteristic curves (AUC), sensitivity, and specificity. RESULTS: There were 30 echocardiograms in the initial cohort (15 LVNC cases, 15 controls). Median age was 1.7 years (IQR 0.2-6.9 years) and systolic function was decreased in 40%. Comparison of diagnostic criteria demonstrated the best interrater agreement and AUC with an X/Y ratio measured in end-diastole in the parasternal short axis in the apical anterolateral segment (κ 0.72, CI 0.43-1.00, p value <0.001), yielding 100% sensitivity and 70-86% specificity, among readers. The least predictive and reproducible method was the NC/C ratio. A validation cohort confirmed the superiority of the X/Y ratio, although the interrater agreement and AUC decreased. CONCLUSION: Measurements according to existing LVNC diagnostic criteria vary by echocardiographic view and segment. Modification of the Chin et al. criteria (Circulation 82:507-513, 1990) using an X/Y ratio <0.5 had the greatest interrater reliability and predictive validity when measured in end-diastole in the parasternal short axis in the apical anterolateral segment. The NC/C ratio had the lowest reliability and predictive validity.

Pulmonary Vein Doppler Patterns in Infants with Single Right Ventricle Anomalies After Initial Staged Palliations.

The aim of this study was to describe serial changes in echocardiographic Doppler pulmonary vein flow (PVF) patterns in infants with single right ventricle (RV) anomalies enrolled in the Single Ventricle Reconstruction trial. Measurement of PVF peak systolic (S) and diastolic (D) velocities, velocity time integrals (VTI), S/D peak velocity and VTI ratios, and frequency of atrial reversal (Ar) waves were made at three postoperative time points in 261 infants: early post-Norwood, pre-stage II surgery, and 14 months. Indices were compared over time, between initial shunt type [modified Blalock-Taussig shunt (MBTS) and right ventricle-to-pulmonary artery shunt (RVPAS)] and in relation to clinical outcomes. S velocities and VTI increased over time while D wave was stable, resulting in increasing S/D peak velocity and VTI ratios, with a median post-Norwood S/D VTI ratio of 1.14 versus 1.38 at pre-stage II and 1.89 at 14 months (P < 0.0001 between intervals). MBTS subjects had significantly higher S/D peak velocity and VTI ratios compared to RVPAS at the post-Norwood and pre-stage II time points (P < 0.0001) but not by 14 months. PVF patterns did not correlate with survival or hospitalization course at 1 year. PVF patterns after Norwood palliation differ from normal infants by having a dominant systolic pattern throughout infancy. PVF differences based upon shunt type resolve by 14 months and did not correlate with clinical outcomes. This study describes normative values and variations in PVF for infants with a single RV from shunt-dependent pulmonary blood flow to cavopulmonary blood flow.

Cardiogenic unilateral pulmonary oedema in an infant with severe residual mitral regurgitation.

An infant with residual severe mitral regurgitation following mitral commissurotomy developed cardiogenic unilateral pulmonary oedema and subsegmental atelectasis that resolved with mechanical mitral valve replacement.

Assessment of Quality of Life in Young Patients with Single Ventricle after the Fontan Operation.

OBJECTIVES: To assess self-reported quality of life (QOL) in a large multicenter cohort of adolescent and young adults surviving Fontan. STUDY DESIGN: Cross-sectional. The Pediatric Quality of Life Inventory (PedsQL) was administered to 408 survivors of Fontan ages 13-25 years enrolled in the Pediatric Heart Network Fontan Follow-up Study. Subjects also completed either the Child Health Questionnaire (age <19 years) or Short Form Health Survey (age ≥ 19 years). PedsQL data were compared with matched controls without a chronic health condition. Correlations between the measures were examined. RESULTS: Mean PedsQL scores for subjects receiving Fontan were significantly lower than those for the control group for physical and psychosocial QOL (P < .001). Overall, 45% of subjects receiving Fontan had scores in the clinically significant impaired range for physical QOL with 30% in the impaired range for psychosocial QOL. For each 1 year increase in age, the physical functioning score decreased by an average of 0.76 points (P = .004) and the emotional functioning score decreased by an average of 0.64 points (P = .03). Among subjects ≥19 years of age, the physical functioning score decreased by an average of 2 points for each year increase in age (P = .02). PedsQL scale scores were significantly correlated with conceptually related Child Health Questionnaire (P < .001) and Short Form Health Survey scores (P < .001). CONCLUSIONS: Survivors of Fontan are at risk for significantly impaired QOL which may decline with advancing age. Routine assessment of QOL is essential to inform interventions to improve health outcomes. The PedsQL allowed QOL assessment from pediatrics to young adulthood. TRIAL REGISTRATION: ClinicalTrials.gov: NCT00132782.

Echocardiographic Assessment of Right Atrial Pressure in a Pediatric and Young Adult Population.

Right atrial pressure (RAP) reflects right-sided cardiac hemodynamics and is useful in management of patients with cardiac and systemic disease. Studies in older adults demonstrated that inferior vena cava (IVC) diameter, IVC collapsibility index, hepatic vein systolic filling fraction (SFF), and right atrial volume (RAV) correlated with mean RAP at catheterization. This study aimed to assess the utility of echocardiographic parameters for assessment of RAP in children and young adults. Patients with pulmonary hypertension or heart transplantation undergoing right heart catheterization were recruited for this prospective observational pilot study. Transthoracic echocardiographic assessment of RAP was performed simultaneously with catheterization. For each parameter, three consecutive cardiac cycles were recorded. Long- and short-axis images of the IVC were obtained. RAV was assessed by area-length and biplane methods. IVC diameters and RAV were indexed to body surface area (BSA)(0.5) and (BSA)(1.4), respectively. Relationships between echocardiographic parameters and mean RAP were correlated using "Pearson's r." Fifty subjects aged 0.3-23 years (median 13, mean 12.3 ± 7 years) were enrolled. Mean RAP correlated modestly with RAV (r = 0.51, p < 0.001). Long-axis IVCmax (r = 0.30, p < 0.05) and tricuspid E wave velocity (r = 0.36, p < 0.01) also correlated with mean RAP. RV free wall tissue Doppler velocities, IVC collapsibility index, and hepatic vein SFF had no relation to mean RAP. In a pediatric and young adult population with pulmonary hypertension or heart transplantation, echocardiographic assessment of RAV and long-axis IVCmax provided a reasonable estimate of mean RAP. IVC collapsibility index and hepatic vein SFF demonstrated no association with mean RAP.

The Norwood operation: Relative effects of surgeon and institutional volumes on outcomes and resource utilization.

BACKGROUND: Hypoplastic left heart syndrome is the most expensive birth defect managed in the United States, with a 5-year survival rate below 70%. Increasing evidence suggests that hospital volumes are inversely associated with mortality for infants with single ventricles undergoing stage 1 surgical palliation. Our aim was to examine the relative effects of surgeon and institutional volumes on outcomes and resource utilisation for these children. METHODS: A retrospective study was conducted using the Pediatric Health Information System database to examine the effects of the number of procedures performed per surgeon and per centre on mortality, costs, and post-operative length of stay for infants undergoing Risk Adjustment for Congenital Heart Surgery risk category six operations at tertiary-care paediatric hospitals, from 1 January, 2004 to 31 December, 2013. Multivariable modelling was used, adjusting for patient and institutional characteristics. Gaussian kernel densities were constructed to show the relative distributions of the effects of individual institutions and surgeons, before and after adjusting for the number of cases performed. RESULTS: A total of 2880 infants from 35 institutions met the inclusion criteria. Mortality was 15.0%. Median post-operative length of stay was 24 days (IQR 14-41). Median standardized inpatient hospital costs were $156,000 (IQR $108,000-$248,000) in 2013 dollars. In the multivariable analyses, higher institutional volume was inversely associated with mortality (p=0.001), post-operative length of stay (p=0.004), and costs (p=0.001). Surgeon volume was associated with none of the measured outcomes. Neither institutional nor surgeon volumes explained much of the wide variation in outcomes and resource utilization observed between institutions and between surgeons. CONCLUSIONS: Increased institutional - but not surgeon - volumes are associated with reduced mortality, post-operative length of stay, and costs for infants undergoing stage 1 palliation.

Progression of right ventricular dilation in repaired tetralogy of Fallot.

PURPOSE: To evaluate factors associated with rapid rate of progression (ROP) of right ventricular (RV) dilation by cardiac MRI in repaired tetralogy of Fallot (TOF) patients. MATERIALS AND METHODS: All patients with repaired TOF with two MRIs were included. RV volumes and function were assessed by MRIs performed on a GE 1.5 Tesla (T) platform. The ROP of RV dilation was calculated as the difference between the last and first RV indexed end-diastolic volumes (iEDV) divided by the time difference. Subjects were divided into two groups: Group I-rapid ROP (top quartile of ROP) and Group II-slower ROP (lower three quartiles). RESULTS: A total of 61 subjects were included. Mean age was 18.0 ± 9.7 years and duration between MRIs 3.4 ± 2.1 years. Median ROP for RV iEDV was 2.0 (-12.7 to 27.8) mL/m(2) /year. Fifteen subjects were in Group I and 46 in Group II. RV iEDV, RV ejection fraction, RV indexed end-systolic volume (iESV) were significantly different between groups. By multivariable analysis, RV iESV was the only independent parameter associated with rapid RV dilation (P < 0.01). CONCLUSION: There was no significant change in RV iEDV in majority of repaired TOF subjects. RV iESV was the best parameter associated with more rapid RV dilation.

Cardiovascular magnetic resonance techniques and findings in children with myocarditis: a multicenter retrospective study.

BACKGROUND: Cardiovascular magnetic resonance (CMR) is increasingly used to diagnose myocarditis in adults but its use in children is not well-established. We sought to describe the presentation, CMR protocol and findings, and outcomes in a multicenter cohort of children with myocarditis. METHODS: Thirteen hospitals retrospectively identified patients meeting the following inclusion criteria: 1) diagnosis of myocarditis by the managing physicians, 2) age <21 years, 3) CMR examination within 30 days of presentation, and 4) no congenital heart disease. Clinical data and test results, including CMR findings, were abstracted from the medical record. RESULTS: For the 143 patients meeting inclusion criteria, the median age was 16.0 years (range, 0.1-20.3) and 139 (97 %) were hospitalized at the time of CMR. The median time from presentation to CMR was 2 days (0-28). The median left ventricular ejection fraction at CMR was 56 % (10-74), with 29 (20 %) below 45 %. The median right ventricular ejection fraction was 54 % (15-72), with 11 (8 %) below 40 %. There was significant variability among centers in the types of tissue characterization techniques employed (p < 0.001). Overall, late gadolinium enhancement (LGE) was used in 100 % of studies, followed by T2-weighted imaging (T2W) in 69 %, first-pass contrast perfusion (FPP) in 48 %, and early gadolinium enhancement (EGE) in 28 %. Abnormalities were most common with LGE (81 %), followed by T2W (74 %), EGE (55 %), and FPP (8 %). The CMR study was interpreted as positive for myocarditis in 117 patients (82 %), negative in 18 (13 %), and equivocal in 7 (5 %), yielding a sensitivity of 82 %. At a median follow-up of 7.1 months (0-87), all patients were alive and 5 had undergone cardiac transplantation. CMR parameters at presentation associated with persistent left ventricular dysfunction were larger left ventricular end-diastolic volume and lower left and right ventricular ejection fraction but not abnormal LGE. CONCLUSIONS: Despite significant practice variation in imaging protocol among centers, CMR had a high sensitivity for the diagnosis of myocarditis in pediatric patients. Abnormalities were most often seen with LGE followed by T2W, EGE, and FPP. These findings should be useful in designing future prospective studies.