Characteristics, Risk Factors, and Outcomes of Extracorporeal Membrane Oxygenation Use in Pediatric Cardiac ICUs: A Report From the Pediatric Cardiac Critical Care Consortium Registry

OBJECTIVES

Cardiopulmonary failure in children with cardiac disease differs from the general pediatric critical care population, yet the epidemiology of extracorporeal membrane oxygenation support in cardiac ICUs has not been described. We aimed to characterize extracorporeal membrane oxygenation utilization and outcomes across surgical and medical patients in pediatric cardiac ICUs.

DESIGN

Retrospective analysis of the Pediatric Cardiac Critical Care Consortium registry to describe extracorporeal membrane oxygenation frequency and outcomes. Within strata of medical and surgical hospitalizations, we identified risk factors associated with extracorporeal membrane oxygenation use through multivariate logistic regression.

SETTING

Tertiary-care children's hospitals.

PATIENTS

Neonates through adults with cardiac disease.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

There were 14,526 eligible hospitalizations from August 1, 2014, to June 30, 2016; 449 (3.1%) included at least one extracorporeal membrane oxygenation run. Extracorporeal membrane oxygenation was used in 329 surgical (3.5%) and 120 medical (2.4%) hospitalizations. Systemic circulatory failure and extracorporeal cardiopulmonary resuscitation were the most common extracorporeal membrane oxygenation indications. In the surgical group, risk factors associated with postoperative extracorporeal membrane oxygenation use included younger age, extracardiac anomalies, preoperative comorbidity, higher Society of Thoracic Surgeons-European Association for Cardiothoracic Surgery category, bypass time, postoperative mechanical ventilation, and arrhythmias (all p < 0.05). Bleeding requiring reoperation (25%) was the most common extracorporeal membrane oxygenation complication in the surgical group. In the medical group, risk factors associated with extracorporeal membrane oxygenation use included acute heart failure and higher Vasoactive Inotropic Score at cardiac ICU admission (both p < 0.0001). Stroke (15%) and renal failure (15%) were the most common extracorporeal membrane oxygenation complications in the medical group. Hospital mortality was 49% in the surgical group and 63% in the medical group; mortality rates for hospitalizations including extracorporeal cardiopulmonary resuscitation were 50% and 83%, respectively.

CONCLUSIONS

This is the first multicenter study describing extracorporeal membrane oxygenation use and outcomes specific to the cardiac ICU and inclusive of surgical and medical cardiac disease. Mortality remains high, highlighting the importance of identifying levers to improve care. These data provide benchmarks for hospitals to assess their outcomes in extracorporeal membrane oxygenation patients and identify unique high-risk subgroups to target for quality initiatives.

Associations Between Unplanned Cardiac Reinterventions and Outcomes After Pediatric Cardiac Operations

BACKGROUND

After pediatric heart operations, we sought to determine the incidence of unplanned cardiac reinterventions during the same hospitalization, assess risk factors for these reinterventions, and explore associations between reinterventions and outcomes. We hypothesized that younger patients undergoing more complex operations would be at greater risk for unplanned cardiac reinterventions and that operative mortality and postoperative length of stay (PLOS) would be greater in patients who undergo reintervention than in those who do not.

METHODS

Patients aged 18 years or younger in The Society of Thoracic Surgeons Congenital Heart Surgery Database (January 2010 to June 2015) were included. We used multivariable regression to evaluate risk factors for unplanned cardiac reintervention (operation or therapeutic catheterization) and associations of reintervention with operative mortality and PLOS.

RESULTS

Of 84,404 patients (117 centers), 21% were neonates and 36% infants. An unplanned cardiac reintervention was performed in 5.4% of patients, including 11.8% of neonates, 5.2% of infants, and 2.8% of children. Independent risk factors for unplanned reintervention included presence of noncardiac anomalies/genetic syndromes, nonwhite race, younger age, lower weight among neonates and infants, prior cardiothoracic operations, preoperative mechanical ventilation, other Society of Thoracic Surgeons preoperative risk factors, and higher Society of Thoracic Surgeons-European Association for Cardiothoracic Surgery Mortality Category (adjusted p < 0.001 for all). Unplanned reintervention was a risk factor for operative mortality (adjusted odds ratio, 5.3; 95% confidence interval, 4.8 to 5.8; p < 0.001) and longer PLOS (adjusted relative risk, 2.3; 95% confidence interval, 2.2 to 2.4; p < 0.001).

CONCLUSIONS

Unplanned cardiac reinterventions are not rare, particularly in neonates, and are independently associated with operative mortality and increased PLOS. Patients at greater risk may be identified preoperatively, presenting opportunities for quality improvement.

Determinants of Variation in Pneumonia Rates After Coronary Artery Bypass Grafting

BACKGROUND

Although conventional wisdom suggests that differences in patient risk profiles drive variability in postoperative pneumonia rates after coronary artery bypass grafting (CABG), this teaching has yet to be empirically tested. We determined to what extent patient risk factors account for hospital variation in pneumonia rates.

METHODS

We studied 324,085 patients undergoing CABG between July 1, 2011, and December 31, 2013, across 998 hospitals using The Society of Thoracic Surgeons Adult Cardiac Database. We developed 5 models to estimate our incremental ability to explain hospital variation in pneumonia rates. Model 1 contained patient demographic characteristics and admission status, while Model 2 added patient risk factors. Model 3 added measures of pulmonary function, Model 4 added measures of cardiac anatomy and function and medications, and Model 5 further added measures of intraoperative and postoperative care.

RESULTS

Although 9,175 patients (2.83%) experienced pneumonia, the median estimated distribution of pneumonia rates across hospitals was 2.5% (25th to 75th percentile: 1.5% to 4.0%). Wide variability in pneumonia rates was evident, with some hospitals having rates more than 6 times higher than others (10th to 90th percentile: 1.0% to 6.1%). Among all five models, Model 2 accounted for the most variability at 4.24%. In total, 2.05% of hospital variation in pneumonia rates was explained collectively by traditional patient factors, leaving 97.95% of variation unexplained.

CONCLUSIONS

Our findings suggest that patient risk profiles only account for a fraction of hospital variation in pneumonia rates; enhanced understanding of other contributory factors (eg, processes of care) is required to lessen the likelihood of such nosocomial infections.

The Impact of Differential Case Ascertainment in Clinical Registry Versus Administrative Data on Assessment of Resource Utilization in Pediatric Heart Surgery

BACKGROUND

Resource utilization in congenital heart surgery is typically assessed using administrative data sets. Recent analyses have called into question the accuracy of coding of cases in administrative data; however, it is unclear whether miscoding impacts assessment of associated resource use.

METHODS

We merged data coded within both an administrative data set and clinical registry on children undergoing heart surgery (2004-2010) at 33 hospitals. The impact of differences in coding of operations between data sets on reporting of postoperative length of stay (PLOS) and total hospital costs associated with these operations was assessed.

RESULTS

For each of the eight operations of varying complexity evaluated (total n = 57,797), there were differences in coding between data sets, which translated into differences in the reporting of associated resource utilization for the cases coded in either data set. There were statistically significant differences in PLOS and cost for seven of the eight operations, although most PLOS differences were relatively small with the exception of the Norwood operation and truncus repair (differences of two days, P < .001). For cost, there was a >5% difference for three of the eight operations and >10% difference for truncus repair (US$10,570; P < .01). Grouping of operations into categories of similar risk appeared to mitigate many of these differences.

CONCLUSION

Differences in coding of cases in administrative versus clinical registry data can translate into differences in assessment of associated PLOS and cost for certain operations. This may be minimized through evaluating larger groups of operations when using administrative data or using clinical registry data to accurately identify operations of interest.

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.

Long-Term Outcomes of Balloon Valvuloplasty for Isolated Pulmonary Valve Stenosis

To evaluate the long-term cumulative incidence of ≥ moderate pulmonary regurgitation (PR) and re-intervention following balloon pulmonary valvuloplasty (BPV). While BPV for pulmonary valve stenosis (PS) relieves obstruction acutely, long-term outcomes are not well documented. Between 1982 and 2002, 211 patients had BPV for isolated PS. Follow-up data were available for 103 patients. Cumulative incidence of ≥ moderate PR and re-intervention was evaluated and risk factors for ≥ moderate PR assessed in univariate and multivariable analyses. Median age at BPV was 0.7 years (range 1 day-42.2 years); peak catheter gradient was 65 mmHg (range 31-169 mmHg); 23% had critical PS. Sixty-two patients had a recent echocardiogram with median follow-up 15.1 years (range 10.1-26.3 years); 60% had ≥ moderate PR. Three patients had pulmonary valve replacement following BPV due to symptomatic severe PR. In univariate analysis, critical PS, younger age, smaller BSA, and smaller pulmonary annulus at the time of BPV, as well as greater baseline PS gradient by catheterization, were associated with ≥ moderate PR (all p < 0.05). In multivariable analysis, only BSA < 0.3 m² was independently associated with ≥ moderate PR (adjusted odds ratio 6.4, 95% confidence interval 1.2-33.6). In the largest study to date of > 10-year outcomes following BPV, 60% of patients with available follow-up data developed ≥ moderate PR. Few patients had pulmonary valve replacement. Patients with lower BSA at the time of BPV were more likely to have greater PR at late follow-up.

Completeness and Accuracy of Local Clinical Registry Data for Children Undergoing Heart Surgery

BACKGROUND

Data routinely captured in clinical registries may be leveraged to enhance efficiency of prospective research. The quality of registry data for this purpose has not been studied, however. We evaluated the completeness and accuracy of perioperative data within congenital heart centers' local surgical registries.

METHODS

Within 12 Pediatric Heart Network (PHN) sites, we evaluated 31 perioperative variables (and their subcategories, totaling 113 unique fields) collected via sites' local clinical registries for submission to The Society of Thoracic Surgeons Database, compared with chart review by PHN research coordinators. Both used standard STS definitions. Data were collected on 10 subjects for 2 to 5 procedures/site and adjudicated by the study team. Completeness and accuracy (agreement of registry data with medical record review by PHN coordinator, adjudicated by the study team) were evaluated.

RESULTS

A total of 56,500 data elements were collected on 500 subjects. With regard to data completeness, 3.1% of data elements were missing from the registry, 0.6% from coordinator-collected data, and 0.4% from both. Overall, registry data accuracy was 98%. In total, 94.7% of data elements were both complete/non-missing and accurate within the registry, although there was variation across data fields and sites. Mean total time for coordinator chart review per site was 49.1 hours versus 7.0 hours for registry query.

CONCLUSIONS

This study suggests that existing surgical registry data constitute a complete, accurate, and efficient information source for prospective research. Variability across data fields and sites also suggest areas for improvement in some areas of data quality.

Clinical Databases and Registries in Congenital and Pediatric Cardiac Surgery, Cardiology, Critical Care, and Anesthesiology Worldwide

The growth in large-scale data management capabilities and the successful care of patients with congenital heart defects have coincidentally paralleled each other for the last three decades, and participation in multicenter congenital heart disease databases and registries is now a fundamental component of cardiac care. This manuscript attempts for the first time to consolidate in one location all of the relevant databases worldwide, including target populations, specialties, Web sites, and participation information. Since at least 1,992 cardiac surgeons and cardiologists began leveraging this burgeoning technology to create multi-institutional data collections addressing a variety of specialties within this field. Pediatric heart diseases are particularly well suited to this methodology because each individual care location has access to only a relatively limited number of diagnoses and procedures in any given calendar year. Combining multiple institutions data therefore allows for a far more accurate contemporaneous assessment of treatment modalities and adverse outcomes. Additionally, the data can be used to develop outcome benchmarks by which individual institutions can measure their progress against the field as a whole and focus quality improvement efforts in a more directed fashion, and there is increasing utilization combining clinical research efforts within existing data structures. Efforts are ongoing to support better collaboration and integration across data sets, to improve efficiency, further the utility of the data collection infrastructure and information collected, and to enhance return on investment for participating institutions.

Report of the National Heart, Lung, and Blood Institute Working Group: An Integrated Network for Congenital Heart Disease Research

The National Heart, Lung, and Blood Institute convened a working group in January 2015 to explore issues related to an integrated data network for congenital heart disease research. The overall goal was to develop a common vision for how the rapidly increasing volumes of data captured across numerous sources can be managed, integrated, and analyzed to improve care and outcomes. This report summarizes the current landscape of congenital heart disease data, data integration methodologies used across other fields, key considerations for data integration models in congenital heart disease, and the short- and long-term vision and recommendations made by the working group.

The Society of Thoracic Surgeons Congenital Heart Surgery Database: 2016 Update on Research

The Society of Thoracic Surgeons Congenital Heart Surgery Database (STS CHSD) is the largest congenital and pediatric cardiac surgical clinical data registry in the world. With more than 400,000 total operations from nearly all centers performing pediatric and congenital heart operations in North America, the STS CHSD is an unparalleled platform for clinical investigation, outcomes research, and quality improvement activities in this subspecialty. In 2015, several major original publications reported analyses of data in the CHSD pertaining to specific diagnostic and procedural groups, age-defined cohorts, or the entire population of patients in the database. Additional publications reported the most recent development, evaluation, and application of metrics for quality measurement and reporting of pediatric and congenital heart operation outcomes. This use of the STS CHSD for outcomes research and for quality measurement continues to expand as database participation and the available wealth of data in it continue to grow. This article reviews outcomes research and quality improvement articles published in 2015 based on STS CHSD data.