Linking the congenital heart surgery databases of the Society of Thoracic Surgeons and the Congenital Heart Surgeons' Society: part 1--rationale and methodology

Novel linkage of the Society of Thoracic Surgeons database and hospital electronic health records

BACKGROUND

Society of Thoracic Surgeons Congenital Heart Surgery Database is the largest congenital heart surgery database worldwide but does not provide information beyond primary episode of care. Linkage to hospital electronic health records would capture complications and comorbidities along with long-term outcomes for patients with CHD surgeries. The current study explores linkage success between Society of Thoracic Surgeons Congenital Heart Surgery Database and electronic health record data in North Carolina and Georgia.

METHODS

The Society of Thoracic Surgeons Congenital Heart Surgery Database was linked to hospital electronic health records from four North Carolina congenital heart surgery using indirect identifiers like date of birth, sex, admission, and discharge dates, from 2008 to 2013. Indirect linkage was performed at the admissions level and compared to two other linkages using a "direct identifier," medical record number: (1) linkage between Society of Thoracic Surgeons Congenital Heart Surgery Database and electronic health records from a subset of patients from one North Carolina institution and (2) linkage between Society of Thoracic Surgeons data from two Georgia facilities and Georgia's CHD repository, which also uses direct identifiers for linkage.

RESULTS

Indirect identifiers successfully linked 79% (3692/4685) of Society of Thoracic Surgeons Congenital Heart Surgery Database admissions across four North Carolina hospitals. Direct linkage techniques successfully matched Society of Thoracic Surgeons Congenital Heart Surgery Database to 90.2% of electronic health records from the North Carolina subsample. Linkage between Society of Thoracic Surgeons and Georgia's CHD repository was 99.5% (7,544/7,585).

CONCLUSIONS

Linkage methodology was successfully demonstrated between surgical data and hospital-based electronic health records in North Carolina and Georgia, uniting granular procedural details with clinical, developmental, and economic data. Indirect identifiers linked most patients, consistent with similar linkages in adult populations. Future directions include applying these linkage techniques with other data sources and exploring long-term outcomes in linked populations.

Evaluating registry-based trial economics: Results from the STRESS clinical trial

Background

Registry-based trials have the potential to reduce randomized clinical trial (RCT) costs. However, observed cost differences also may be achieved through pragmatic trial designs. A systematic comparison of trial costs across different designs has not been previously performed.

Methods

We conducted a study to compare the current Steroids to Reduce Systemic inflammation after infant heart surgery (STRESS) registry-based RCT vs. two established designs: pragmatic RCT and explanatory RCT. The primary outcome was total RCT design costs. Secondary outcomes included: RCT duration and personnel hours. Costs were estimated using the Duke Clinical Research Institute's pricing model.

Results

The Registry-Based RCT estimated duration was 31.9 weeks greater than the other designs (259.5 vs. 227.6 weeks). This delay was caused by the Registry-Based design's periodic data harvesting that delayed site closing and statistical reporting. Total personnel hours were greatest for the Explanatory design followed by the Pragmatic design and the Registry-Based design (52,488 vs 29,763 vs. 24,480 h, respectively). Total costs were greatest for the Explanatory design followed by the Pragmatic design and the Registry-Based design ($10,140,263 vs. $4,164,863 vs. $3,268,504, respectively). Thus, Registry-Based total costs were 32 % of the Explanatory and 78 % of the Pragmatic design.

Conclusion

Total costs for the STRESS RCT with a registry-based design were less than those for a pragmatic design and much less than an explanatory design. Cost savings reflect design elements and leveraging of registry resources to improve cost efficiency, but delays to trial completion should be considered.

Research Enterprise of the Congenital Heart Surgeons' Society 2018 to 2023: History, Accomplishments, Transformation, and Challenges

The history of the research arm of the Congenital Heart Surgeons' Society (CHSS) through 2017 was contained within two prior publications that covered CHSS history in general. The present article is the first to focus explicitly on the research enterprise, with emphasis on the period 2018 to 2023. During this time, the challenges of continuing to build multiple cohorts with lifelong follow-up and to transform the enterprise to a premiere research organization became manifest. Although continuing its commitment to produce impactful research results and to educate the Kirklin/Ashburn Fellow, the research team devoted considerable effort to defining the problems of cohort relevance, workflow, data management, long-term patient follow-up, CHSS member engagement, and the regulatory burden. The team wrote a proposal outlining ways to solve the challenges. A major change from a single-institution "Data Center" to a two-institution Center for Research & Quality (CRQ) was made, assuring increased faculty members and resources. The proposed changes to structure and process began execution in mid-2022. A second Kirklin/Ashburn Fellowship position was created. Between 2018 and 2022, the CRQ produced 17 publications and launched five new research initiatives. This article chronicles the exciting five-year period in which the CHSS research enterprise began a transformation with the intent to become the premiere research organization in the world in the specialty of congenital cardiac surgery.

The Academic Impact of Congenital Heart Surgeons' Society (CHSS) Studies

PURPOSE

We reviewed all 64 articles ever published by The Congenital Heart Surgeons' Society (CHSS) Data Center to estimate the academic impact of these peer-reviewed articles.

MATERIALS AND METHODS

The Congenital Heart Surgeons' Society has performed research based on 12 Diagnostic Inception Cohorts. The first cohort (Transposition) began enrolling patients on January 1, 1985. We queried PubMed to determine the number of publications that referenced each of the 64 journal articles generated by the datasets of the 12 Diagnostic Inception Cohorts that comprise the CHSS Database. Descriptive summaries of the data were tabulated using mean with standard deviation and median with range.

RESULTS

Sixty-four peer-reviewed papers have been published based on the CHSS Database. Fifty-nine peer-reviewed articles have been published based on the 12 Diagnostic Inception Cohorts, and five additional articles have been published based on Data Science. Excluding the recently established Diagnostic Inception Cohort for patients with Ebstein malformation of tricuspid valve, the number of papers published per cohort ranged from 1 for coarctation to 11 for transposition of the great arteries. The 11 articles generated from the CHSS Transposition Cohort were referenced by a total of 111 articles (median number of references per journal article = 9 [range = 0-22, mean = 10.1]). Overall, individual articles were cited by an average of 11 (mean), and a maximum of 41 PubMed-listed publications. Overall, these 64 peer-reviewed articles based on the CHSS Database were cited 692 times in PubMed-listed publications. The first CHSS peer-reviewed article was published in 1987, and during the 35 years from 1987 to 2022, inclusive, the annual number of CHSS publications has ranged from 0 to 7, with a mean of 1.8 publications per year (median = 1, mode = 1).

CONCLUSION

Congenital Heart Surgeons' Society studies are widely referenced in the pediatric cardiac surgical literature, with over 10 citations per published article. These cohorts provide unique information unavailable in other sources of data. A tool to access this analysis is available at: [https://data-center.chss.org/multimedia/files/2022/CAI.pdf].

World Journal for Pediatric and Congenital Heart Surgery-The Official Journal of the Congenital Heart Surgeons' Society

The World Journal for Pediatric and Congenital Heart Surgery (WJPCHS) was established in 2009, as a means of advancing the educational and scholarship goals of the World Society for Pediatric and Congenital Heart Surgery. WJPCHS has grown steadily since the first issue was published in April 2010. In 2017, the Congenital Heart Surgeons' Society and the European Congenital Heart Surgeons Association both designated WJPCHS as the official journal of their respective organizations. The CHSS and ECHSA represent the face and the voice of congenital heart surgery in North America (United States and Canada) and in Europe, respectively. Each organization has advanced the science of surgical management of congenital heart disease through multicenter outcomes analyses, which have strongly and positively influenced the care of patients around the world.

A Narrative Review of Multiinstitutional Data Registries of Pediatric Congenital Heart Disease in Pediatric Cardiac Anesthesia and Critical Care Medicine

Congenital heart disease (CHD) is one of the most common birth anomalies. While the care of children with CHD has improved over recent decades, children with CHD who undergo general anesthesia remain at increased risk for morbidity and mortality. Electronic health record systems have enabled institutions to combine data on the management and outcomes of children with CHD in multicenter registries. The application of descriptive analytics methods to these data can improve clinicians' understanding and care of children with CHD. This narrative review covers efforts to leverage multicenter data registries relevant to pediatric cardiac anesthesia and critical care to improve the care of children with CHD.

A mapping algorithm for International Classification of Diseases 10th Revision codes for congenital heart surgery benchmark procedures

BACKGROUND

Administrative billing data are critical to many initiatives in congenital heart surgery. Mapping algorithms for International Classification of Disease, 10th Revision diagnosis and procedure codes to clinical registry procedure definitions will allow identification of surgical cases and account for patient and procedural factors within administrative data. Our objectives were to develop mapping logic to crosswalk International Classification of Disease, 10th Revision procedure codes to 10 Society of Thoracic Surgeons Congenital Heart Surgery Database benchmark and beta-test the algorithm.

METHODS

Patients undergoing Society of Thoracic Surgeons Congenital Heart Surgery Database benchmark procedures from 2015 to 2019 were identified and served as the gold standard. Cases were linked on direct identifiers to cases from the Pediatric Health Information System Database. Two independent teams developed International Classification of Disease, 10th Revision-based algorithms for cases capture. Algorithms were compared and iteratively refined to optimize sensitivity and specificity. Operative mortalities for cases identified in the administrative versus registry data were compared.

RESULTS

Overall sensitivity was 91% and specificity was 99% for capture of benchmark operations using International Classification of Diseases 10th Revision codes. Sensitivity was more than 90% in identifying 6 of the 10 individual benchmark procedures and more than 98% sensitive in identifying Fontan, Glenn, and arterial switch with ventricular septal defect procedures. Specificity was more than 98% for all benchmark operations. There were no statistical differences in operative mortality between cases identified in the administrative versus the registry data.

CONCLUSIONS

Novel mapping algorithm for International Classification of Disease, 10th Revision procedure codes enables identification of congenital heart benchmark procedures within administrative billing data. This crosswalk facilitates population-based congenital heart surgical research and quality assessment.

National and regional registries for congenital heart diseases: Strengths, weaknesses and opportunities

BACKGROUND

We aim to establish a new and informative bi-national Registry for Congenital Heart Disease (CHD) patients in Australia and New Zealand, to document the burden of disease and clinical outcomes for patients with CHDs across the lifespan. When planning for the implementation of this Registry, we sought to evaluate the strengths and weaknesses of existing national and large regional CHD databases.

METHODS

We characterised 15 large multi-institutional databases of pediatric and/or adult patients with CHD, documenting the richness of their datasets, the ease of linkage to other databases, the coverage of the target cohort and the strategies utilised for quality control.

RESULTS

The best databases contained demographic, clinical, physical, laboratory and patient-reported data, and were linked at least to the national/regional death registry. They also employed automatic data verification and regular manual audits. Coverage ranged from around 25% of all eligible CHD cases for larger databases to near 100% for some smaller registries of patients with specific CHD lesions, such as the Australia and New Zealand Fontan Registry.

CONCLUSIONS

Existing national and regional CHD databases have strengths and weaknesses; few combine complete coverage with high quality and regularly audited data, across the broad range of CHDs.

Factors associated with mortality or transplantation versus Fontan completion after cavopulmonary shunt for patients with tricuspid atresia

OBJECTIVE

Tricuspid atresia with normally related great vessels (TA) is considered the optimal substrate for the Fontan pathway. The factors associated with death or transplantation after cavopulmonary shunt (CPS) are underappreciated. We aimed to determine factors associated with CPS-Fontan interstage death/transplantation versus transition to Fontan in TA.

METHODS

A total of 417 infants younger than 3 months of age with TA were enrolled (January 1999 to February 2020) from 40 institutions into the Congenital Heart Surgeons' Society TA cohort. Parametric competing risk methodology was used to determine factors associated with the competing end points of death/transplantation without Fontan completion, and transition to Fontan.

RESULTS

CPS was performed in 382 patients with TA; of those, 5% died or underwent transplantation without transition to Fontan and 91% transitioned to Fontan by 5 years after CPS. Prenatal diagnosis (hazard ratio [HR], 0.74; P < .001) and pulmonary artery band (PAB) at CPS (HR, 0.50; P < .001) were negatively associated with Fontan completion. Preoperative moderate or greater mitral valve regurgitation (HR, 3.0; P < .001), concomitant mitral valve repair (HR, 11.0; P < .001), PAB at CPS (HR, 3.0; P < .001), postoperative superior vena cava interventions (HR, 9.0; P < .001), and CPS takedown (HR, 40.0; P < .001) were associated with death/transplantation.

CONCLUSIONS

The mortality rate after CPS in patients with TA is notable. Those with preoperative mitral valve regurgitation remain a high-risk group. PAB at the time of CPS being associated with both increased risk of death and decreased Fontan completion may represent a deleterious effect of antegrade pulmonary blood flow in the CPS circulation.

Variants of significance: medical genetics and surgical outcomes in congenital heart disease

PURPOSE OF REVIEW

This article reviews the current understanding and limitations in knowledge of the effect genetics and genetic diagnoses have on perioperative and postoperative surgical outcomes in patients with congenital heart disease (CHD).

RECENT FINDINGS

Presence of a known genetic diagnosis seems to effect multiple significant outcome metrics in CHD surgery including length of stay, need for extracorporeal membrane oxygenation, mortality, bleeding, and heart failure. Data regarding the effects of genetics in CHD is complicated by lack of standard genetic assessment resulting in inaccurate risk stratification of patients when analyzing data. Only 30% of variation in CHD surgical outcomes are explained by currently measured variables, with 2.5% being attributed to diagnosed genetic disorders, it is thought a significant amount of the remaining outcome variation is because of unmeasured genetic factors.

SUMMARY

Genetic diagnoses clearly have a significant effect on surgical outcomes in patients with CHD. Our current understanding is limited by lack of consistent genetic evaluation and assessment as well as evolving knowledge and discovery regarding the genetics of CHD. Standardizing genetic assessment of patients with CHD will allow for the best risk stratification and ultimate understanding of these effects.

Expanding analytic possibilities in pediatric solid organ transplantation through linkage of administrative and clinical registry databases

Database linkage is a common strategy to expand analytic possibilities. Our group recently completed a linkage between the SRTR and PHIS databases for pediatric heart transplant recipients. The aim of this project was to expand the linkage between SRTR and PHIS to include liver, kidney, lung, heart-lung, and small bowel transplants. All patients (<21 years) who underwent liver, kidney, lung, heart-lung, or small bowel transplant were identified from the PHIS database using APR-DRG codes (2002-2018). Linkage was performed in a stepwise approach using indirect identifiers. Hospital costs were estimated based on hospital charges and cost-to-charge ratios, inflated to 2018 dollars and described by transplant type. A total of 14 061 patients overlapped between databases. Of these, 13 388 (95.2%) were uniquely linked. Linkage success ranged from 92.6% to 97.8% by organ system. A total of 12 940 (92%) patients had complete cost data. Hospitalization costs were greatest for patients undergoing small bowel transplantation with a median cost of $734 454 (IQR $336 174 - $1 504 167), followed by heart $565 386 (IQR $352 813 - $999 216), heart-lung $471 573 (IQR $328 523 - 992 438), lung $303 536 (IQR $215 383 - $612 749), liver $200 448 (IQR $130 880 - $357 897), and kidney transplant $94 796 (IQR $73 157 -$131 040). We report a robust linkage between the SRTR and PHIS databases, providing an invaluable tool to assess resource utilization in solid organ transplant recipients. Our analysis provides contemporary cost data for pediatric solid organ transplantation from the largest US sample reported to date. It also provides a platform for expanded analyses in the pediatric transplant population.

Intervention for arch obstruction after the Norwood procedure: Prevalence, associated factors, and practice variability

OBJECTIVE

Arch obstruction after the Norwood procedure is common and contributes to mortality. We determined the prevalence, associated factors, and practice variability of arch reintervention and assessed whether arch reintervention is associated with mortality.

METHODS

From 2005 to 2017, 593 neonates in the Congenital Heart Surgeons' Society Critical Left Heart Obstruction cohort underwent a Norwood procedure. Median follow-up was 3.7 years. Multivariable parametric models, including a modulated renewal analysis, were performed.

RESULTS

Of the 593 neonates, 146 (25%) underwent 218 reinterventions for arch obstruction after the Norwood procedure: catheter-based (n = 168) or surgical (n = 50) at a median age of 4.3 months (quartile 1-quartile 3, 2.6-5.7). Interdigitation of the distal aortic anastomosis was protective against arch reintervention. Development of ≥ moderate tricuspid valve regurgitation and right ventricular dysfunction at any point was associated with arch reintervention. Nonsignificant variables for arch reintervention included shunt type and preoperative aortic measurements. Surgical arch reintervention was protective against arch reintervention, but transcatheter reintervention was associated with increased reintervention. Arch reintervention was not associated with increased mortality. There was wide institutional variation in incidence of arch reintervention (range, 0-40 reinterventions per 100 years patient follow-up) and in preintervention gradient (range, 0-64 mm Hg).

CONCLUSIONS

Interdigitation of the distal aortic anastomosis during the Norwood procedure decreased the risk of arch reintervention. Surgical arch reintervention is more definitive than transcatheter. Arch reintervention after the Norwood procedure is not associated with increased mortality. Serial surveillance for arch obstruction, integrated with changes in right ventricular function and tricuspid valve regurgitation, is recommended after the Norwood procedure to improve outcomes.

Incremental History of the Congenital Heart Surgeons’ Society (2014-2018)

The history of the first 41 years of the Congenital Heart Surgeons Society (CHSS) was recorded in 2015 which chronicled the metamorphosis of a small informal meeting into a mature organization with bylaws, officers, committees, funded research, the Kirklin-Ashburn Fellowship, and a vision to become the premier organization of congenital heart surgery in North America. Chief among these transformations was the implementation and development of the CHSS Data Center. Member participation, fellowship education, and significant outcomes research have been the hallmark of the CHSS. This incremental historical review highlights continued CHSS sentinel advances. Fifty-three CHSS Data Center manuscripts have been published. Citation scores (number of literature citations that each manuscript has accrued) have been collated and analyzed by cohort study. The average citation score for all manuscripts was 75.4 ± 76.3 (range: 1-333). The Kirklin/Ashburn Fellowship continues to thrive with academic achievements and generous contributions to the endowment. The World Journal of Pediatric and Congenital Heart Surgery has been adopted as the official organ of the CHSS. A Past President’s Dinner has been inaugurated serving as a senior advisory committee to the Executive Council. Toronto Work Weekends continue. Congenital Heart Surgeons Society growth has accrued to 159 active members and 82 institutional members. Future considerations include the size, content, and duration of the annual meeting; the potential for increased membership; and political penetrance into national cardiothoracic governing organizations regarding committee appointments, executive council representation, and education initiatives. Congenital Heart Surgeons Society has achieved numerous advances during this incremental period.

A unique linkage of administrative and clinical registry databases to expand analytic possibilities in pediatric heart transplantation research

BACKGROUND

Large clinical, research, and administrative databases are increasingly utilized to facilitate pediatric heart transplant (HTx) research. Linking databases has proven to be a robust strategy across multiple disciplines to expand the possible analyses that can be performed while leveraging the strengths of each dataset. We describe a unique linkage of the Scientific Registry of Transplant Recipients (SRTR) database and the Pediatric Health Information System (PHIS) administrative database to provide a platform to assess resource utilization in pediatric HTx.

METHODS

All pediatric patients (1999-2016) who underwent HTx at a hospital enrolled in the PHIS database were identified. A linkage was performed between the SRTR and PHIS databases in a stepwise approach using indirect identifiers. To determine the feasibility of using these linked data to assess resource utilization, total and post-HTx hospital costs were assessed.

RESULTS

A total of 3188 unique transplants were identified as being present in both databases and amenable to linkage. Linkage of SRTR and PHIS data was successful in 3057 (95.9%) patients, of whom 2896 (90.8%) had complete cost data. Median total and post-HTx hospital costs were $518,906 (IQR $324,199-$889,738), and $334,490 (IQR $235,506-$498,803) respectively with significant differences based on patient demographics and clinical characteristics at HTx.

CONCLUSIONS

Linkage of the SRTR and PHIS databases is feasible and provides an invaluable tool to assess resource utilization. Our analysis provides contemporary cost data for pediatric HTx from the largest US sample reported to date. It also provides a platform for expanded analyses in the pediatric HTx population.

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.

History of the Congenital Heart Surgeons’ Society

The Congenital Heart Surgeons’ Society is a group of over 100 pediatric heart surgeons representing 72 institutions that specialize in the treatment of patients with congenital heart defects. The Society began in 1972 and incorporated as a not-for-profit charitable organization in 2004. It has become the face and voice of congenital heart surgery in North America. In 1985, the Society established a data center for multicenter clinical research studies to encourage congenital heart professionals to participate in improving outcomes for our patients. The goals of the Congenital Heart Surgeons’ Society are to stimulate the study of congenital cardiac physiology, pathology, and management options which are instantiated in data collection, multi-institutional studies, and scientific meetings. Honest and open discussion of problems with possible solutions to the challenges facing congenital heart professionals have been the strength of the Congenital Heart Surgeons’ Society. It is imperative for the growth of an organization to know from where it came in order to know to where it is going. The purpose of this article is to review the history of the Congenital Heart Surgeons’ Society.

The science of assessing the outcomes and improving the quality of the congenital and paediatric cardiac care

PURPOSE OF REVIEW

Although significant progress has been made in the care of patients with paediatric and congenital cardiac disease, optimization of outcomes remains a constant goal. This review article will discuss the latest advances in the science of assessing the outcomes and improving the quality of the congenital and paediatric cardiac care, and will also review some of the latest associated research.

RECENT FINDINGS

Important advances continue to be made in each of the following domains: standardized nomenclature; established uniform core dataset; evaluation of case complexity; verification of the completeness and accuracy of the data; collaboration between subspecialties; strategies for longitudinal follow-up; and incorporating quality improvement. In January 2015, the Society of Thoracic Surgeons Congenital Heart Surgery Database (STS-CHSD) will begin voluntary public reporting of programmatic congenital cardiac surgical outcomes using a new risk model that includes both procedural risk (as defined by the procedure itself and STAT Categories) and a number of patient-specific characteristics including age, weight, prior cardiothoracic operation, prematurity, chromosomal abnormalities, syndromes, noncardiac congenital anatomic abnormalities and preoperative factors. Clinical databases have been linked with administrative database to answer questions neither dataset can answer independently, providing new information about long-term mortality, rates of rehospitalization, long-term morbidity, comparative effectiveness of various treatments, and the cost of healthcare. Multiple research initiatives have recently been published using STS-CHSD.

SUMMARY

The science of assessing the outcomes and improving the quality of congenital and paediatric cardiac care continues to evolve. Recent advances will facilitate the continued evolution of a meaningful method of multiinstitutional outcomes analysis for congenital and paediatric cardiac surgery.

Linking the congenital heart surgery databases of the Society of Thoracic Surgeons and the Congenital Heart Surgeons' Society: part 2--lessons learned and implications

PURPOSE

A link has been created between the Society of Thoracic Surgeons Congenital Heart Surgery Database (STS-CHSD) and the Congenital Heart Surgeons' Society Database (CHSS-D). Five matrices have been created that facilitate the automated identification of patients who are potentially eligible for the five active CHSS studies using the STS-CHSD. These matrices are now used to (1) estimate the denominator of patients eligible for CHSS studies and (2) compare "eligible and enrolled patients" to "potentially eligible and not enrolled patients" to assess the generalizability of CHSS studies.

METHODS

The matrices were applied to 40 consenting institutions that participate in both the STS-CHSD and the CHSS to (1) estimate the denominator of patients that are potentially eligible for CHSS studies, (2) estimate the completeness of enrollment of patients eligible for CHSS studies among all CHSS sites, (3) estimate the completeness of enrollment of patients eligible for CHSS studies among those CHSS institutions participating in each CHSS cohort study, and (4) compare "eligible and enrolled patients" to "potentially eligible and not enrolled patients" to assess the generalizability of CHSS studies. The matrices were applied to all participants in the STS-CHSD to identify patients who underwent frequently performed operations and compare "eligible and enrolled patients" to "potentially eligible and not enrolled patients" in following five domains: (1) age at surgery, (2) gender, (3) race, (4) discharge mortality, and (5) postoperative length of stay. Completeness of enrollment was defined as the number of actually enrolled patients divided by the number of patients identified as being potentially eligible for enrollment.

RESULTS

For the CHSS Critical Left Ventricular Outflow Tract Study (LVOTO) study, for the Norwood procedure, completeness of enrollment at centers actively participating in the LVOTO study was 34%. For the Norwood operation, discharge mortality was 15% among 227 enrolled patients and 16% among 1768 nonenrolled potentially eligible patients from the 40 consenting institutions. Median postoperative length of stay was 31 days and 26 days for these enrolled and nonenrolled patients. For the CHSS anomalous aortic origin of a coronary artery (AAOCA) study, for AAOCA repair, completeness of enrollment at centers actively participating in the AAOCA study was 40%.

CONCLUSION

Determination of the denominator of patients eligible for CHSS studies and comparison of "eligible and enrolled patients" to "potentially eligible and not enrolled patients" provides an estimate of the extent to which patients in CHSS studies are representative of the overall population of eligible patients; however, opportunities exist to improve enrollment.

Public health research in congenital heart disease

Public health research is an integral part of the study of congenital heart disease. While this type of research has become more popular, particularly over the past decade, it has a history that stretches back to almost the beginnings of pediatric cardiology as a field. This review aims to introduce the concepts and methodologies of public health and how they relate to congenital heart disease, describe some of the challenges of traditional research methods in congenital heart disease, describe the history of public health research, and demonstrate the relevance of public health research, particularly databases, to pediatric cardiology fellows.