Development of the data registry for the Cardiac Neurodevelopmental Outcome Collaborative

Children with congenital heart disease (CHD) can face neurodevelopmental, psychological, and behavioural difficulties beginning in infancy and continuing through adulthood. Despite overall improvements in medical care and a growing focus on neurodevelopmental screening and evaluation in recent years, neurodevelopmental disabilities, delays, and deficits remain a concern. The Cardiac Neurodevelopmental Outcome Collaborative was founded in 2016 with the goal of improving neurodevelopmental outcomes for individuals with CHD and pediatric heart disease. This paper describes the establishment of a centralised clinical data registry to standardize data collection across member institutions of the Cardiac Neurodevelopmental Outcome Collaborative. The goal of this registry is to foster collaboration for large, multi-centre research and quality improvement initiatives that will benefit individuals and families with CHD and improve their quality of life. We describe the components of the registry, initial research projects proposed using data from the registry, and lessons learned in the development of the registry.

Quality of life after Ross procedure in children

INTRODUCTION

Health-related quality of life in children who have undergone the Ross procedure has not been well characterised. The aim of this study was to characterise health-related quality of life in this cohort and compare to children with other CHD.

METHOD

In this cross sectional, single-centre study, health-related quality of life was assessed in patients who underwent a non-neonatal Ross procedure using the Pediatric Quality of Life Inventory. Ross cohort scores were compared with healthy norms, patients with CHD requiring no surgical intervention or had curative surgery (Severity 2, S2) and patients who were surgically repaired with ≥1 surgical procedure and with significant residual lesion or need for additional surgery (Severity 3, S3). Associations between Pediatric Quality of Life Inventory score and patient factors were also examined.

RESULTS

68 patients completed surveys. Nearly one-sixth of patients had overall scores below the cut-off for at-risk status for impaired health-related quality of life. There was no difference in overall health-related quality of life score between the Ross cohort and healthy children (p = 0.56) and S2 cohort (p = 0.97). Health-related quality of life was significantly higher in the Ross cohort compared to S3 cohort (p = 0.02). This difference was driven by a higher psychosocial health-related quality of life in the Ross cohort as compared to S3 cohort (p = 0.007). Anxiety scores were significantly worse in the Ross cohort compared to both S2 (p = 0.001) and S3 (p = 0.0017), respectively.

CONCLUSION

Children who have undergone a Ross procedure report health-related quality of life equivalent to CHD not requiring therapy and superior to CHD with residual lesions. Despite these reassuring results, providers should be aware of potential anxiety among Ross patients.

Spillover of Early Extubation Practices From the Pediatric Heart Network Collaborative Learning Study

OBJECTIVES

The Pediatric Heart Network Collaborative Learning Study used collaborative learning strategies to implement a clinical practice guideline that increased rates of early extubation after infant repair of tetralogy of Fallot and coarctation of the aorta. We assessed early extubation rates for infants undergoing cardiac surgeries not targeted by the clinical practice guideline to determine whether changes in extubation practices spilled over to care of other infants.

DESIGN

Observational analyses of site's local Society of Thoracic Surgeons Congenital Heart Surgery Database and Pediatric Cardiac Critical Care Consortium Registry.

SETTING

Four Pediatric Heart Network Collaborative Learning Study active-site hospitals.

PATIENTS

Infants undergoing ventricular septal defect repair, atrioventricular septal defect repair, or superior cavopulmonary anastomosis (lower complexity), and arterial switch operation or isolated aortopulmonary shunt (higher complexity).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Aggregate outcomes were compared between the 12 month pre-clinical practice guideline and 12 months after study completion (Follow Up). In infants undergoing lower complexity surgeries, early extubation increased during Follow Up compared with Pre-Clinical Practice Guideline (30.2% vs 18.8%, p = 0.006), and hours to initial postoperative extubation decreased. We observed variation in these outcomes by surgery type, with only ventricular septal defect repair associated with a significant increase in early extubation during Follow Up compared with Pre-Clinical Practice Guideline (47% vs 26%, p = 0.006). Variation by study site was also seen, with only one hospital showing an increase in early extubation. In patients undergoing higher complexity surgeries, there was no difference in early extubation or hours to initial extubation between the study eras.

CONCLUSIONS

We observed spillover of extubation practices promoted by the Collaborative Learning Study clinical practice guideline to lower complexity operations not included in the original study that was sustainable 1 year after study completion, though this effect differed across sites and operation subtypes. No changes in postoperative extubation outcomes following higher complexity surgeries were seen. The significant variation in outcomes by site suggests that center-specific factors may have influenced spillover of clinical practice guideline practices.

Sustainability of Infant Cardiac Surgery Early Extubation Practices After Implementation and Study

BACKGROUND

The Pediatric Heart Network Collaborative Learning Study (PHN CLS) successfully changed practice at four hospitals to increase the rate of early extubation within 6 hours after infant heart surgery. It is unknown whether this practice continued after study completion.

METHODS

We linked the PHN CLS dataset to the Pediatric Cardiac Critical Care Consortium registry to compare outcomes at four active hospitals between the study period (post-clinical practice guideline [CPG]) and the first year after study completion (follow-up) after a 3-month washout. Inclusion and exclusion criteria were the same across eras. Primary outcome was early extubation rate after tetralogy of Fallot or aortic coarctation repair. Secondary outcomes included time to first extubation and intensive care and hospital lengths of stay.

RESULTS

There were 121 patients in the post-CPG era and 139 patients in the follow-up era with no difference in patient characteristics or operation subtypes. Post-CPG early extubation rate declined from 67% to 30% in follow-up (p < 0.0001); time to first extubation increased (4.5 versus 13.5 hours, p < 0.0001). One hospital maintained the rate of early extubation (72% versus 67%), whereas the other three hospitals had significantly lower rates in follow-up (p < 0.02 for each). Intensive care (2.8 versus 2.9 days) and postoperative hospital (6 versus 5 days) stays did not differ between eras (p > 0.05 for both). Findings were consistent across operation subtypes.

CONCLUSIONS

Extubation practice in the first year of follow-up after the PHN CLS reverted toward prestudy levels. One of four hospitals maintained its early extubation strategy, suggesting that specific implementation and maintenance approaches may effectively sustain impact from quality initiatives.

Duration of Postoperative Mechanical Ventilation as a Quality Metric for Pediatric Cardiac Surgical Programs

BACKGROUND

Few metrics exist to assess quality of care at pediatric cardiac surgical programs, limiting opportunities for benchmarking and quality improvement. Postoperative duration of mechanical ventilation (POMV) may be an important quality metric because of its association with complications and resource utilization. In this study we modelled case-mix-adjusted POMV duration and explored hospital performance across POMV metrics.

METHODS

This study used the Pediatric Cardiac Critical Care Consortium clinical registry to analyze 4,739 hospitalizations from 15 hospitals (October 2013 to August 2015). All patients admitted to pediatric cardiac intensive care units after an index cardiac operation were included. We fitted a model to predict duration of POMV accounting for patient characteristics. Robust estimates of SEs were obtained using bootstrap resampling. We created performance metrics based on observed-to-expected (O/E) POMV to compare hospitals.

RESULTS

Overall, 3,108 patients (65.6%) received POMV; the remainder were extubated intraoperatively. Our model was well calibrated across groups; neonatal age had the largest effect on predicted POMV. These comparisons suggested clinically and statistically important variation in POMV duration across centers with a threefold difference observed in O/E ratios (0.6 to 1.7). We identified 1 hospital with better-than-expected and 3 hospitals with worse-than-expected performance (p < 0.05) based on the O/E ratio.

CONCLUSIONS

We developed a novel case-mix-adjusted model to predict POMV duration after congenital heart operations. We report variation across hospitals on metrics of O/E duration of POMV that may be suitable for benchmarking quality of care. Identifying high-performing centers and practices that safely limit the duration of POMV could stimulate quality improvement efforts.

Clinical epidemiology and centre variation in chylothorax rates after cardiac surgery in children: a report from the Pediatric Cardiac Critical Care Consortium

Introduction Chylothorax after paediatric cardiac surgery incurs significant morbidity; however, a detailed understanding that does not rely on single-centre or administrative data is lacking. We described the present clinical epidemiology of postoperative chylothorax and evaluated variation in rates among centres with a multicentre cohort of patients treated in cardiac ICU.

METHODS

This was a retrospective cohort study using prospectively collected clinical data from the Pediatric Cardiac Critical Care Consortium registry. All postoperative paediatric cardiac surgical patients admitted from October, 2013 to September, 2015 were included. Risk factors for chylothorax and association with outcomes were evaluated using multivariable logistic or linear regression models, as appropriate, accounting for within-centre clustering using generalised estimating equations.

RESULTS

A total of 4864 surgical hospitalisations from 15 centres were included. Chylothorax occurred in 3.8% (n=185) of hospitalisations. Case-mix-adjusted chylothorax rates varied from 1.5 to 7.6% and were not associated with centre volume. Independent risk factors for chylothorax included age <1 year, non-Caucasian race, single-ventricle physiology, extracardiac anomalies, longer cardiopulmonary bypass time, and thrombosis associated with an upper-extremity central venous line (all p<0.05). Chylothorax was associated with significantly longer duration of postoperative mechanical ventilation, cardiac ICU and hospital length of stay, and higher in-hospital mortality (all p<0.001).

CONCLUSIONS

Chylothorax after cardiac surgery in children is associated with significant morbidity and mortality. A five-fold variation in chylothorax rates was observed across centres. Future investigations should identify centres most adept at preventing and managing chylothorax and disseminate best practices.

Seminal Postoperative Complications and Mode of Death After Pediatric Cardiac Surgical Procedures

BACKGROUND

Understanding the seminal complications leading to death after pediatric cardiac surgical procedures may provide opportunities to reduce mortality. This study analyzed all deaths at two pediatric cardiac surgical programs and developed a method to identify the seminal complications and modes of death.

METHODS

Trained nurses abstracted all cases of in-hospital mortality meeting inclusion criteria from each site over 5 years (2008 to 2012). Complication definitions were consistent with those of a multicenter clinical registry. An adjudication committee assigned a seminal complication in each case (the complication initiating the cascade of events leading to death). Seminal complications were grouped into categories to designate "mode of death." The epidemiology of seminal complications and of mode of death was described.

RESULTS

In 191 subjects, low cardiac output syndrome (71% of all subjects), cardiac arrest (52%), and arrhythmia (48%) were the most common complications. The committee assigned low cardiac output syndrome (30%), failure to separate from bypass (16%), and cardiac arrest (12%) most frequently as seminal complications. Seminal complications occurred a median 2 hours (interquartile range [IQR], 0 to 35 hours) postoperatively. Patients experienced a median of seven (IQR, 3 to 12) additional complications before death at a median of 15 days (IQR, 4 to 46). Systemic circulatory failure was the most common mode of death (51%), followed by inadequate pulmonary blood flow (13%) and cardiac arrest (12%).

CONCLUSIONS

Seminal complications occurred early postoperatively, and systemic circulatory failure was the most common mode of death. Our classification system is likely scalable for subsequent multicenter analysis to understand cause-specific mortality variation across hospitals and to drive quality improvement.

Severe Acute Kidney Injury Following Stage 1 Norwood Palliation: Effect on Outcomes and Risk of Severe Acute Kidney Injury at Subsequent Surgical Stages

OBJECTIVES

To identify associations of severe acute kidney injury early after stage 1 (Norwood) operation with risk of severe acute kidney injury and comorbidities at subsequent palliative stages in patients with hypoplastic left heart syndrome and other single ventricle lesions with left-sided obstruction.

DESIGN

Retrospective cohort study. Severe acute kidney injury defined as Kidney Disease Improving Global Outcomes stage 3.

SETTING

Single pediatric cardiac center.

PATIENTS

Infants less than or equal to 28 days old with single ventricle physiology and left-sided obstruction undergoing stage 1 operation between September 2007 and November 2012 (n = 136).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The occurrence rate of severe acute kidney injury was 21% (28/136) following stage 1, 12% (12/98) following stage 2 palliation (superior cavo-pulmonary anastomosis), and 10% (7/73) following stage 3 palliation (total cavo-pulmonary anastomosis). Severe acute kidney injury early after stage 1 operation was significantly associated with continuous intravenous loop diuretic infusion, need for extracorporeal membrane oxygenation, and in-hospital death (all p < 0.05). Gestational age at birth was associated with severe acute kidney injury at stage 2 (p = 0.04) and stage 3 (p = 0.01). Severe acute kidney injury at stage 1 was an independent risk factor for severe acute kidney injury at stage 2 (adjusted odds ratio, 4.3; 95% CI, 1.1-16.9; p = 0.04). Development of severe acute kidney injury after stage 1 was associated with longer mechanical ventilation time after stage 3 (p = 0.047).

CONCLUSIONS

Severe acute kidney injury after stage 1 palliation was an independent risk factor for developing severe acute kidney injury at stage 2, and was associated with prolonged duration of mechanical ventilation following stage 3. Information on the incidence and associated risk factors for postoperative acute kidney injury in hypoplastic left heart syndrome patients from multiple congenital heart centers is a necessary next step to further understand the long-term burden of severe acute kidney injury after staged palliation.

Risk Factors for Interstage Mortality Following the Norwood Procedure: Impact of Sociodemographic Factors

Interstage mortality remains significant for patients undergoing staged palliation for hypoplastic left heart syndrome and other related single right ventricle malformations (HLV). The purpose of this study was to identify factors related to demographics, socioeconomic position, and perioperative course associated with post-Norwood hospital discharge, pre-stage 2, interstage mortality (ISM). Medical record review was conducted for patients with HLV, born from 1/2000 to 7/2009 and discharged alive following the Norwood procedure. Sociodemographic and perioperative factors were reviewed. Patients were determined to have ISM if they died between Norwood procedure hospital discharge and stage 2 palliation. Univariable and multivariable logistic regressions were performed to identify risk factors associated with ISM. A total of 273 patients were included in the analysis; ISM occurred in 32 patients (12%). Multivariable analysis demonstrated that independent risk factors for interstage mortality included teen mothers [adjusted odds ratio (AOR) 6.6, 95% confidence interval (CI) 1.9-22.5], single adult caregivers (AOR 4.1, 95% CI 1.2-14.4), postoperative dysrhythmia (AOR 2.7, 95% CI 1.1-6.4), and longer ICU stay (AOR 2.7, 95% CI 1.2-6.1). Anatomic and surgical course variables were not associated with ISM in multivariable analysis. Patients with HLV are at increased risk of ISM if born to a teen mother, if they lived in a home with only one adult caregiver, suffered a postoperative dysrhythmia, or experienced a prolonged ICU stay. These risk factors are identifiable, and thus these infants may be targeted for interventions to reduce ISM.

Fontan-associated protein-losing enteropathy and plastic bronchitis

OBJECTIVE

To characterize the medical history, disease progression, and treatment of current-era patients with the rare diseases Fontan-associated protein-losing enteropathy (PLE) and plastic bronchitis.

STUDY DESIGN

A novel survey that queried demographics, medical details, and treatment information was piloted and placed online via a Facebook portal, allowing social media to power the study. Participation regardless of PLE or plastic bronchitis diagnosis was allowed. Case control analyses compared patients with PLE and plastic bronchitis with uncomplicated control patients receiving the Fontan procedure.

RESULTS

The survey was completed by 671 subjects, including 76 with PLE, 46 with plastic bronchitis, and 7 with both. Median PLE diagnosis was 2.5 years post-Fontan. Hospitalization for PLE occurred in 71% with 41% hospitalized ≥ 3 times. Therapy varied significantly. Patients with PLE more commonly had hypoplastic left ventricle (62% vs 44% control; OR 2.81, 95% CI 1.43-5.53), chylothorax (66% vs 41%; OR 2.96, CI 1.65-5.31), and cardiothoracic surgery in addition to staged palliation (17% vs 5%; OR 4.27, CI 1.63-11.20). Median plastic bronchitis diagnosis was 2 years post-Fontan. Hospitalization for plastic bronchitis occurred in 91% with 61% hospitalized ≥ 3 times. Therapy was very diverse. Patients with plastic bronchitis more commonly had chylothorax at any surgery (72% vs 51%; OR 2.47, CI 1.20-5.08) and seasonal allergies (52% vs 36%; OR 1.98, CI 1.01-3.89).

CONCLUSIONS

Patient-specific factors are associated with diagnoses of PLE or plastic bronchitis. Treatment strategies are diverse without clear patterns. These results provide a foundation upon which to design future therapeutic studies and identify a clear need for forming consensus approaches to treatment.

Relation of right ventricular mass and volume to functional health status in repaired tetralogy of Fallot

After repair of tetralogy of Fallot, right ventricular (RV) mass and mass:volume ratio may reflect RV remodeling and adverse outcomes. This study aimed to evaluate the relation of RV mass to functional health status and subsequent adverse RV remodeling and to determine whether RV mass measurement in systole could improve reproducibility. In 53 patients with tetralogy of Fallot (median 29 years old) who previously underwent cardiovascular magnetic resonance and completed the Short Form 36, version 2 (Optum, Eden Prairie, MN), short-axis images were analyzed for RV end-diastolic volume and diastolic and systolic mass, indexed to body surface area. The most recent subsequent cardiovascular magnetic resonance study (before pulmonary valve or conduit replacement) was evaluated for change in RV end-diastolic volume and ejection fraction. Diastolic indexed mass ≥37.3 g/m(2) (odds ratio 7.6, p = 0.02) predicted decreased general health scores. In patients with normal RV ejection fraction, indexed mass correlated with Physical Component Summary and general health scores. RV diastolic mass:volume ratio >0.2 had a strong association with subsequent increase in RV end-diastolic volume (odds ratio 26.1, p = 0.002). Systolic RV mass measurement had excellent correlation with diastolic measurement (r = 0.97, p <0.0001), but did not improve intraobserver or interobserver variability. In conclusion, RV mass relates to functional health status and adverse RV remodeling and can be measured with good reproducibility. RV mass should be routinely evaluated in this population and is best measured in diastole; further study is necessary to evaluate longitudinal changes in functional health status and RV parameters.

Fluoroscopy-guided Umbilical Venous Catheter Placement in Infants with Congenital Heart Disease

OBJECTIVE

The objective of this study was to (1) describe the technical aspects of fluoroscopy-guided umbilical venous catheter placement (FGUVCP); and (2) determine the procedural success rate, factors contributing to procedural failure, and risks of the procedure.

BACKGROUND

Umbilical venous catheters are advantageous compared with femoral venous access, but can be difficult to place at the bedside.

MATERIALS AND METHODS

This was a retrospective chart review from a single tertiary care referral institution.

RESULTS

FGUVCP was successful in 138 of 180 patients (76.7%) over a seven-year period. Patients in whom FGUVCP was successful were younger at the time of procedure compared with patients in whom FGUVCP was unsuccessful (median 18.2 vs. 22.2 hours, P = .03). The optimal age cutoff to predict FGUVCP success was 20 hours with a high positive predictive value (82.4%) but low negative predictive value (32.5%). No other variables were associated with procedural failure, though functional univentricular heart and older gestational age trended toward statistical significance. Median radiation time, contrast exposure, and blood loss were 3.2 minutes, 1 mL, and 1 mL, respectively. A total of 10 complications in 10 patients were associated with FGUVCP.

CONCLUSIONS

FGUVCP is a safe and highly successful way to obtain central venous access in neonates with congenital heart disease. Older age at the time of procedure is associated with procedural failure, but utilization of an age cutoff may not be clinically useful.

Differential effect of body mass index on pediatric heart transplant outcomes based on diagnosis

The impact of nutritional status on HTx waitlist mortality in children is unknown, and there are conflicting data regarding the role of nutrition in post-HTx survival. This study examined the influence of nutrition on waitlist and post-HTx outcomes in children. Children 2-18 yr listed for HTx from 1997 to 2011 were identified from the OPTN database and stratified by BMI percentile. Multivariable logistic regression evaluated the influence of BMI on waitlist mortality. Cox proportional hazard regression assessed the impact of BMI on post-HTx mortality. When all 2712 patients were analyzed, BMI did not impact waitlist, one-, or five-yr mortality. However, when stratified by diagnosis, BMI > 95% (AOR 1.96; 95% CI 1.24, 3.09) and BMI < 1% (AOR 2.17; 95% CI 1.28, 3.68) were independent risk factors for waitlist mortality in patients with CM. BMI did not impact waitlist mortality in CHD and did not impact post-HTx outcomes, regardless of diagnosis. BMI > 95% and BMI < 1% are independent risk factors for waitlist mortality in patients with CM, but not CHD. This suggests differing risk factors based on disease etiology, and an individualized approach to risk assessment based on diagnosis may be warranted.

Splanchnic near-infrared spectroscopy and risk of necrotizing enterocolitis after neonatal heart surgery

Infants with critical congenital heart disease, especially patients with a single-ventricle (SV) physiology, are at increased risk for the development of necrotizing enterocolitis (NEC). Decreased splanchnic oxygen delivery may contribute to the development of NEC and may be detected by regional oximetry (rSO2) via splanchnic near-infrared spectroscopy (NIRS). This prospective study enrolled 64 neonates undergoing biventricular (BV) repair or SV palliation for CHD and monitored postoperative splanchnic rSO2 before and during initiation of enteral feedings to determine whether changes in rSO2 are associated with risk of NEC. Suspected or proven NEC was observed in 32 % (11/34) of the SV subjects and 0 % (0/30) of the BV subjects (p = 0.001). Compared with the BV subjects, the SV palliated subjects had significantly lower splanchnic rSO2 before and during initiation of enteral feedings, but the groups showed no difference after correction for lower pulse oximetry (SpO2) in the SV group. The clinical parameters were similar among the SV subjects with and without NEC except for cardiopulmonary bypass times, which were longer for the patients who experienced NEC (126 vs 85 min; p = 0.03). No difference was observed in splanchnic rSO2 or in the SpO2-rSO2 difference between the SV subjects with and without NEC. Compared with the patients who had suspected or no NEC, the subjects with proven NEC had a lower average splanchnic rSO2 (32.6 vs 47.0 %; p = 0.05), more time with rSO2 less than 30 % (48.8 vs 6.7 %; p = 0.04) at one-fourth-volume feeds, and more time with SpO2-rSO2 exceeding 50 % (33.3 vs 0 %; p = 0.03) before feeds were initiated. These data suggest that splanchnic NIRS may be a useful tool for assessing risk of NEC, especially in patients with an SV physiology.

Echocardiographic evaluation of ventricular function in children with pulmonary hypertension

Although described in adults, it remains unclear whether ventricular dysfunction exists in pediatric patients with pulmonary hypertension (PHN). The goal of this study was to identify differences in echocardiographic indices of ventricular function among pediatric PHN patients. From 2009 to 2011, pediatric PHN patients with normal intracardiac anatomy and age-matched controls (1:3 ratio) were enrolled in this retrospective case-control study. Diagnosis of PHN was based on tricuspid regurgitation velocity or septal position estimating right-ventricular (RV) pressure >50 % systemic. Measures of RV and left ventricular systolic and diastolic function, including tissue Doppler imaging (TDI) of the mitral annulus (MA) and tricuspid annulus (TA), were compared. Enrollees included 25 PHN patients and 75 age-matched controls (mean age 7.5 years [range 1 day to 19 years]). Parameters of RV systolic and diastolic function were worse in PHN patients. Compared with controls, PHN patients had significantly decreased tricuspid valve inflow ratio, decreased TA TDI early diastolic velocities, decreased systolic velocities, increased tricuspid E/E' ratio (all p < 0.01) and increased myocardial performance index. In an age-stratified analysis, TDI measures in PHN patients <1 year of age were similar to controls, whereas differences in TA TDI velocities and MA TDI velocities were noted in patients ≥1 year of age. Abnormalities in Doppler echocardiographic indices of ventricular systolic and diastolic function were identified in pediatric PHN patients and were more prominent with older age. These indices are promising for serial noninvasive monitoring of disease severity, but further correlation with catheterization-derived measures is needed.

Social media methods for studying rare diseases

For pediatric rare diseases, the number of patients available to support traditional research methods is often inadequate. However, patients who have similar diseases cluster "virtually" online via social media. This study aimed to (1) determine whether patients who have the rare diseases Fontan-associated protein losing enteropathy (PLE) and plastic bronchitis (PB) would participate in online research, and (2) explore response patterns to examine social media's role in participation compared with other referral modalities. A novel, internet-based survey querying details of potential pathogenesis, course, and treatment of PLE and PB was created. The study was available online via web and Facebook portals for 1 year. Apart from 2 study-initiated posts on patient-run Facebook pages at the study initiation, all recruitment was driven by study respondents only. Response patterns and referral sources were tracked. A total of 671 respondents with a Fontan palliation completed a valid survey, including 76 who had PLE and 46 who had PB. Responses over time demonstrated periodic, marked increases as new online populations of Fontan patients were reached. Of the responses, 574 (86%) were from the United States and 97 (14%) were international. The leading referral sources were Facebook, internet forums, and traditional websites. Overall, social media outlets referred 84% of all responses, making it the dominant modality for recruiting the largest reported contemporary cohort of Fontan patients and patients who have PLE and PB. The methodology and response patterns from this study can be used to design research applications for other rare diseases.

Abnormal nutrition affects waitlist mortality in infants awaiting heart transplant

BACKGROUND

Although nutritional status affects survival after heart transplant (HTx) in adults and older children, its effect on outcomes in young children is unknown. This study aimed to assess the effect of pre-HTx nutrition on outcomes in this population.

METHODS

Children aged 0 to 2 years old listed for HTx from 1997 to 2011 were identified from the Organ Procurement and Transplantation Network database. Nutritional status was classified according to percentage of ideal body weight at listing and at HTx. Logistic regression analysis evaluated the risk of waitlist mortality. Cox proportional hazard models assessed the effect of nutrition on post-HTx survival.

RESULTS

Of 1,653 children evaluated, 899 (54%) had normal nutrition at listing, 445 (27%) were mildly wasted, 203 (12%) were moderate or severely wasted, and 106 (6%) had an elevated weight-to-height (W:H) ratio. Moderate or severe wasting (adjusted odds ratio, 1.9; 95% confidence interval, 1.3-2.7) and elevated W:H (adjusted odds ratio, 1.7; 95% confidence interval, 1.1-2.6) were independent risk factors for waitlist mortality. HTx was performed in 1,167 patients, and 1,016 (87%) survived to 1-year post-HTx. Nutritional status at listing or at HTx was not associated with increased post-HTx mortality. Nutritional status did not affect the need for early reoperation, dialysis, or the incidences of infection, stroke, or rejection before hospital discharge.

CONCLUSIONS

Moderate or severe wasting and an elevated W:H are independent risk factors for waitlist mortality in patients aged < 2 years but do not affect post-HTx mortality. Optimization of pre-HTx nutritional status constitutes a strategy to reduce waitlist mortality in this age range.

Utility of a clinical practice guideline in treatment of chylothorax in the postoperative congenital heart patient

BACKGROUND

Chylothorax after congenital heart surgery is a common complication with associated morbidities, but consensus treatment guidelines are lacking. Variability exists in the duration of medical treatment and timing for surgical intervention.

METHODS

After institution of a clinical practice guideline for management of postoperative chylothorax at a single center, pediatric cardiothoracic intensive care unit (ICU) in June 2010, we retrospectively analyzed 2 cohorts of patients: those with chylothorax from January 2008 to May 2010 (early cohort; n=118) and from June 2010 to August 2011 (late cohort; n=45). Data collected included demographics, cardiac surgical procedure, treatments for chylothorax, bloodstream infections, hospital mortality, length of hospitalization, duration of mechanical ventilation, and device utilization.

RESULTS

There were no demographic differences between the cohorts. No differences were found in octreotide use or surgical treatments for chylothorax. Significant differences were found in median times to chylothorax diagnosis (9 in early cohort versus 6 days in late cohort, p=0.004), ICU length of stay (18 vs 9 days, p=0.01), hospital length of stay (30 vs 23 days, p=0.005), and total durations of mechanical ventilation (11 vs 5 days, p=0.02), chest tube use (20 vs 14 days, p=0.01), central venous line use (27 vs 15 days, p=0.001), and NPO status (9.5 vs 6 days, p=0.04).

CONCLUSIONS

Institution of a clinical practice guideline for treatment of chylothorax after congenital heart surgery was associated with earlier diagnosis, reduced hospital length of stay, mechanical ventilation, and device utilization for these patients.

Retrospective database research in pediatric cardiology and congenital heart surgery: an illustrative example of limitations and possible solutions

BACKGROUND

Secondary use of data, whether from clinical information systems or registries, for carrying out clinical research in rare diseases is a common practice but is fraught with potential errors. We sought to elucidate some of the limitations of database research and describe possible solutions to overcome these limitations.

METHODS

Using a disease model of a rare postsurgical outcome, we evaluated the ability of four different data sources to correctly identify patients who had that outcome both as individual databases and also when used in conjunction with each other. These results were compared with manual chart review.

RESULTS

The sensitivity of the various databases to pick up a rare and specific outcome was poor (9.9%-37%), while the specificities were fairly good (91%-96.7%). By combining the databases, the sensitivity was increased to as much as 56.8% without a large decrease in the specificity (85.2%-91.6%). The electronic medical record (EMR) search engine had the highest sensitivity (96.9%) and a high specificity (89.3%) with a very high negative predictive value (99.4%).

CONCLUSION

For rare and specific diseases or outcomes, a single data source search methodology can miss large numbers of patients and potentially bias study results. Combining overlapping databases can improve the ability to capture these rare diseases or outcomes. While chart review remains the most accurate way to obtain complete case capture, new tools like EMR search engines can facilitate the efficiency of this process without sacrificing search quality.

Risk factors for surgical site infection in pediatric cardiac surgery patients undergoing delayed sternal closure

OBJECTIVES

To determine the incidence of surgical site infections (SSIs) in congenital heart surgery (CHS) patients undergoing delayed sternal closure (DSC) and to evaluate risk factors for SSI.

METHODS

A nested case-control study was performed within a cohort of CHS patients undergoing DSC at our institution between 2005 and 2009. Cases met 2008 Centers for Disease Control and Prevention criteria for SSI; control subjects were matched based on year of surgery. Uni- and multivariate logistic regressions were performed to identify SSI risk factors.

RESULTS

Of 375 patients who underwent DSC, 43 (11%) developed an SSI. The analysis included 172 patients (43 cases, 129 controls); 118 (69%) were neonates, 80 (47%) had undergone Norwood procedure, and 150 (87%) had DSC initiated in the operating room. Case and control subjects were similar based on pre- and intraoperative characteristics. Duration of mechanical ventilation, intensive care unit and hospital length of stay, and mortality were significantly greater in patients with an SSI. Multiple periods of DSC, longer duration of DSC, greater dependence on parenteral nutrition, and extracorporeal membrane oxygenation were significantly associated with SSI in univariate analyses. Multivariate analysis demonstrated that multiple periods of DSC (adjusted odds ratio, 5.9; 95% confidence interval, 1.7-20.1) and extracorporeal membrane oxygenation (adjusted odds ratio, 2.9; 95% confidence interval, 1.1-7.6) remained independent risk factors for SSI.

CONCLUSIONS

For CHS patients undergoing DSC, extracorporeal membrane oxygenation and multiple periods of DSC are independent risk factors for SSI. New strategies for prevention and prophylaxis of SSI may be indicated for these high-risk patients who have worse outcomes and greater health care resource utilization.

Impact of vitamin C on endothelial function and exercise capacity in patients with a Fontan circulation

OBJECTIVE

  To evaluate the impact of antioxidant therapy on functional health status in Fontan-palliated patients. Design.  Prospective, randomized, double-blind, placebo-controlled trial.

PATIENTS

  Fifty-three generally asymptomatic Fontan patients.

INTERVENTIONS

  Patients were randomized to receive either high-dose ascorbic acid (vitamin C) or placebo for 4 weeks.

OUTCOME MEASURES

  Peripheral vascular function, as measured with endothelium-dependent digital pulse amplitude testing (EndoPAT), and exercise capacity were assessed before and after study drug treatment. Primary outcome measures included the EndoPAT index and peripheral arterial tonometry (PAT) ratio, both validated markers of vascular function. Secondary outcome measures included peak oxygen consumption and work.

RESULTS

  Twenty-three vitamin C- and 21 placebo-assigned subjects completed the protocol (83%). Median age and time from Fontan completion were 15 (interquartile range [IQR] 11.7-18.2) and 11.9 years (IQR 9.0-15.7), respectively. Right ventricular morphology was dominant in 30 (57%). Outcome measures were similar between groups at baseline. Among all subjects, vitamin C therapy was not associated with a statistical improvement in either primary or secondary outcome measures. In subjects with abnormal vascular function at baseline, compared with placebo, vitamin C therapy more frequently resulted in normalization of the EndoPAT index (45% vs. 17%) and PAT ratio (38% vs. 13%).

CONCLUSIONS

  Short-term therapy with vitamin C does not alter endothelial function or exercise capacity in an asymptomatic Fontan population overall. Vitamin C may provide benefit to a subset of Fontan patients with abnormal vascular function.

Usefulness of peripheral vascular function to predict functional health status in patients with Fontan circulation

After the Fontan operation, patients are at a substantial risk of the development of impaired functional health status. Few early markers of suboptimal outcomes have been identified. We sought to assess the association between peripheral vascular function and functional health status in Fontan-palliated patients. Asymptomatic Fontan patients (n = 51) and age- and gender-matched healthy controls (n = 22) underwent endothelial pulse amplitude testing using a noninvasive fingertip peripheral arterial tonometry (PAT) device. Raw data were transformed into the PAT ratio, an established marker of vascular function. Cardiopulmonary exercise testing was performed using the Bruce protocol. In the Fontan cohort, 94% of patients were New York Heart Association functional class I and 88% had a B-type natriuretic peptide level of <50 pg/ml. The baseline pulse amplitude, a measure that reflects the arterial tone at rest, was greater in the Fontan patients than in the controls (median 2.74, interquartile range 1.96 to 4.13 vs median 1.86, interquartile range 1.14 to 2.79, p = 0.03). The PAT ratio, a measure of reactive hyperemia, was lower in Fontan patients (median 0.17, interquartile range -0.04 to 0.44, vs median 0.50, interquartile range 0.27 to 0.74, p = 0.002). The key parameters of exercise performance, including peak oxygen consumption (median 28.8 ml/kg/min, interquartile range 25.6 to 33.2 vs median 45.5 ml/kg/min, interquartile range 41.7 to 49.9, p <0.0001) and peak work (median 192 W, interquartile range 150 to 246 vs median 330, interquartile range 209 to 402 W, p <0.0001), were lower in Fontan patients than in the controls. The PAT ratio correlated with the peak oxygen consumption (r = 0.28, p = 0.02) and peak work (r = 0.26, p = 0.03). In conclusion, in an asymptomatic Fontan population, there is evidence of reduced basal peripheral arterial tone and vasodilator response, suggesting dysfunction of the endothelium-derived nitric oxide pathway. Vasodilator function appears to correlate with exercise performance.

Population-based analysis of survival for hypoplastic left heart syndrome

OBJECTIVE

To analyze survival patterns among infants with hypoplastic left heart syndrome (HLHS) in the State of Michigan.

STUDY DESIGN

Cases of HLHS prevalent at live birth were identified and confirmed within the Michigan Birth Defects Registry from 1992 to 2005 (n=406). Characteristics of infants with HLHS were compared with a 10:1 random control sample.

RESULTS

Compared with 4060 control subjects, the 406 cases of HLHS were more frequently male (62.6% vs 51.4%), born prematurely (<37 weeks gestation; 15.3% vs 8.7%), and born at low birth weight (LBW) (<2.5 kg; 16.0% vs 6.6%). HLHS 1-year survival rate improved over the study period (P=.041). Chromosomal abnormalities, LBW, premature birth, and living in a high poverty neighborhood were significantly associated with death. Controlling for neighborhood poverty, term infants versus preterm with HLHS or LBW were 3.2 times (95% CI: 1.9-5.3; P<.001) more likely to survive at least 1 year. Controlling for age and weight, infants from low-poverty versus high-poverty areas were 1.8 times (95% CI: 1.1-2.8; P=.015) more likely to survive at least 1 year.

CONCLUSIONS

Among infants with HLHS in Michigan, those who were premature, LBW, had chromosomal abnormalities, or lived in a high-poverty area were at increased risk for early death.

Tricuspid valve repair in hypoplastic left heart syndrome

Tricuspid valve regurgitation (TR) remains an obstacle for staged palliation of hypoplastic left heart syndrome (HLHS). Because previous results from our institution suggested that posterior leaflet obliteration (PLO) is effective in tricuspid valve repair (TVR), we preferentially used this method. This report analyzes the effect of this preference on repair success and patient survival. All HLHS patients with 3-4+ preoperative TR undergoing TVR between 2002 and 2007 were retrospectively analyzed. Clinical and echocardiographic data were used to determine outcomes. Seventy-one percent (17 of 24) of patients had success at early outcome; the remaining 29% experienced early failure. Sixty-three percent (15 of 24) of patients demonstrated success at late outcome. Early outcome status was found to be a predictor of late outcome status (OR 22.9, P = 0.0037). Overall survival was 71% (17 of 24). Survival could not be shown to be associated with early or late outcome status (odds ratio = 0.96). A preference for PLO was found to give improved, long-lasting results for HLHS patients. Success at immediate outcome was predictive of success with time. PLO has the advantage of being simple and reproducible and produces good outcomes in this challenging group. Continued follow-up will be necessary to confirm long-term outcomes.

Peripheral neuropathy in survivors of childhood acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) is the most common form of cancer in children. Recent advances in treatment have led to dramatically improved survival rates. Standard ALL treatment includes multiple administrations of the chemotherapeutic drug vincristine, which is a known neurotoxic agent. Although peripheral neuropathy is a well-known toxicity among children receiving vincristine acutely, the long-term effects on the peripheral nervous system in these children are not clear. The objective of this study was to determine the prevalence of neuropathy and its impact on motor function and quality of life (QOL) among children who survived ALL. Thirty-seven survivors of childhood ALL aged 8-18 underwent evaluation for neuropathy through self-reported symptoms, standardized examinations, and nerve conduction studies (NCS). Functional impact of neuropathy was assessed using the Bruininks-Oseretsky test of Motor Proficiency (BOT-2). QOL was assessed using the PedsQL. Nerve conduction study abnormalities were seen in 29.7% of children who were longer than 2 years off therapy for ALL. Most children with an abnormal examination or NCS did not have subjective symptoms. Although overall motor function was below population norms on the BOT-2, presence of neuropathy did not significantly correlate with motor functional status or QOL.

Bone mineral density in young adult survivors of acute lymphoblastic leukemia

BACKGROUND

The purpose of the current study was to determine the prevalence of low bone mineral density (BMD) (ie, osteopenia) and identify factors associated with low BMD in young adult survivors of childhood acute lymphoblastic leukemia (ALL).

METHODS

Dual energy x-ray absorptiometry was used to evaluate BMD in 74 randomly selected, long-term childhood ALL survivors initially treated in Minneapolis/St. Paul, Minnesota. Growth hormone (GH)-releasing hormone-arginine stimulation testing was conducted to evaluate peak GH level, and insulin-like growth factor I (IGF-I) and other markers of endocrine functioning were also evaluated in relation to BMD.

RESULTS

The mean age at the time of interview was 30 years, and the mean time since diagnosis was 24 years. Low BMD (Z-score, < or = -1) was present in 24% of subjects, including 1 with osteoporosis. Low BMD was substantially more prevalent in men than in women and was strongly associated with short height. The mean height Z-score for those with low BMD was -1.44, compared with a height Z-score of -0.39 (P < .01) for those with normal BMD. GH insufficiency, low IGF-I Z-score, and current smoking were also suggestive risk factors for low BMD.

CONCLUSIONS

In this long-term follow-up study of childhood ALL survivors, low BMD was found to be more prevalent than expected based on population normative data, specifically in men. The health consequences of early-onset BMD problems in childhood ALL survivors need to be carefully monitored.

Hospital mortality for Norwood and arterial switch operations as a function of institutional volume

Regionalization of complex surgical procedures to high-volume centers is a model for improving hospital survival. We analyzed the effect of institutional volume on hospital mortality for the Norwood and arterial switch operations (ASO) as representative high-complexity neonatal cardiac procedures. Analysis of discharge data from the 2003 Kids' Inpatient Database (KID) was conducted. Association between institutional volume and in-hospital mortality was examined for the ASO or Norwood procedure. Logistic regression analysis was performed to calculate the probability of hospital mortality for both procedures.Significant inverse associations between institutional volume and in-hospital mortality for the Norwood procedure (p </= 0.001) and the ASO (p = 0.006) were demonstrated. In-hospital mortality decreased for the ASO as institutional volume increased, with mortality rates of 9.4% for institutions performing two ASOs/year, 3.2% for 10 ASOs/year, and 0.8% for 20 ASOs/year. Similarly, in-hospital mortality rates for hypoplastic left heart syndrome were 34.8% for two Norwood procedures/year, 25.7% for 10 Norwood procedures/year, and 16.7% for 20 Norwood procedures/year. An inverse relation was observed between in-hospital mortality and institutional volume for ASO and the Norwood procedure. These results suggest that selective regionalization of complex neonatal cardiac procedures might result in significant improvement in hospital survival nationally.

Health knowledge about symptoms of heart attack and stroke in adult survivors of childhood acute lymphoblastic leukemia

PURPOSE

Children with acute lymphoblastic leukemia (ALL), the most common pediatric malignancy, have a 5-year survival rate of better than 80%. Long-term survivors of childhood ALL, however, carry an elevated risk of early mortality from cardiac events and stroke and a disproportionately high prevalence of dyslipidemia and obesity, presumably as an adverse effect of treatment.

METHODS

As part of a clinical follow-up study of 70 young adult survivors of childhood ALL, we evaluated the degree to which this high-risk group differed in knowledge about symptoms of heart attack and stroke from that of a population-based comparison group frequency-matched by age, sex, and body mass index. Questions from the Behavioral Risk Factor Surveillance System were used to assess health knowledge.

RESULTS

Survivors of ALL scored considerably worse on symptom knowledge than did their population counterparts. The strongest association was observed for chest pain as a symptom of heart attack: ALL survivors were 14-fold more likely than the comparison group to answer the question incorrectly. Seventy-seven percent of survivors failed to identify pain in the jaw, neck, or back as a heart attack symptom.

CONCLUSIONS

These results indicate an important gap in knowledge and underscore the need for health education among survivors of childhood leukemia that includes information about symptoms of myocardial infarction and stroke.

Depressive symptoms, sex, and risk for Alzheimer's disease

Depression associates with increased risk for dementia and Alzheimer's disease (AD), although it is unclear whether it represents an actual risk factor or a prodrome. To determine the relative hazard of premorbid depressive symptomatology for development of dementia and AD, we studied risk for incident dementia and AD over a 14-year period in 1,357 community-dwelling men and women participating in the 40-year prospective Baltimore Longitudinal Study of Aging. Screening for depressive symptoms, comprehensive medical and neuropsychological evaluations were prospectively collected every 2 years. Time-dependent proportional hazards of development of AD or dementia were calculated separately for men and women, with symptoms of depression detected at 2-, 4-, and 6-year intervals before onset of dementia symptoms. Vascular risk factors were analyzed as covariates. Premorbid depressive symptoms significantly increased risk for dementia, particularly AD in men but not in women. Hazard ratios were approximately two times greater than for individuals without history of depressive symptoms, an effect independent of vascular disease. We conclude that the impact of depressive symptoms on risk for dementia and AD may vary with sex. Further studies assessing separately the role of depression as a risk factor in men and women are necessary.