Introduction

Over the past 30 years, substantial progress has been made in the art and science of outcomes analysis and quality improvement for the treatment of patients with pediatric and congenital heart disease.[1],[2],[3],[4],[5],[6],[7],[8],[9],[10],[11],[12],[13],[14],[15],[16],[17],[18],[19],[20],[21],[22],[23],[24],[25],[26],[27],[28],[29],[30],[31],[32],[33],[34],[35],[36],[37],[38],[39],[40],[41],[42],[43],[44],[45],[46],[47],[48],[49],[50],[51],[52],[53],[54],[55],[56],[57],[58],[59],[60],[61],[62],[63],[64],[65],[66],[67],[68],[69],[70],[71],[72],[73],[74],[75],[76],[77],[78],[79],[80],[81],[82],[83],[84],[85],[86],[87],[88],[89],[90],[91],[92],[93],[94],[95],[96],[97],[98],[99],[100],[101],[102],[103],[104],[105],[106],[107],[108],[109],[110],[111],[112],[113],[114],[115],[116],[117],[118],[119],[120],[121],[122],[123],[124],[125],[126],[127],[128],[129],[130],[131],[132],[133],[134],[135],[136],[137],[138],[139],[140],[141],[142],[143],[144],[145],[146],[147],[148],[149],[150],[151],[152],[153],[154],[155],[156],[157],[158],[159],[160],[161],[162],[163],[164],[165],[166],[167],[168],[169],[170],[171],[172],[173],[174],[175],[176],[177],[178],[179],[180],[181],[182],[183],[184],[185],[186],[187],[188],[189],[190],[191],[192],[193],[194],[195],[196],[197],[198],[199],[200],[201],[202],[203],[204],[205],[206],[207],[208],[209],[210],[211],[212],[213],[214],[215],[216],[217],[218],[219],[220],[221],[222],[223],[224],[225],[226],[227],[228],[229],[230],[231],[232],[233],[234],[235],[236],[237],[238],[239],[240],[241],[242],[243],[244],[245],[246],[247],[248],[249],[250],[251],[252],[253],[254],[255],[256],[257],[258],[259],[260],[261],[262],[263],[264],[265],[266],[267],[268],[269],[270],[271],[272],[273],[274],[275],[276],[277],[278],[279],[280],[281],[282],[283],[284],[285],[286],[287],[288],[289],[290],[291],[292],[293],[294],[295],[296],[297],[298],[299],[300],[301],[302],[303],[304],[305],[306],[307],[308],[309],[310],[311],[312],[313],[314],[315],[316],[317],[318],[319],[320],[321],[322],[323],[324],[325],[326],[327],[328],[329],[330],[331],[332],[333],[334],[335],[336],[337],[338],[339],[340],[341],[342],[343],[344],[345],[346],[347],[348],[349],[350] Much of this progress centers on the development and evolution of databases for pediatric and congenital cardiac care.

Congenital cardiac malformations are the most common types of birth defects. Congenital heart disease (CHD) is present in approximately 10 out of every 1000 live births in the United States of America.[351] Before the introduction of current diagnostic modalities (including echocardiography), the estimated incidence if CHD ranged from five to eight per 1000 live births. With improved diagnostic modalities, many more patients with milder forms of CHD can now be identified, so that contemporary estimates of the prevalence of congenital cardiac disease range from eight to twelve per 1000 live births.[352],[353],[354] About 25% of neonates and infants with a congenital cardiac defect undergo surgery or catheter-directed intervention in their first year of life.[351] In the United States, approximately 97% of all patients undergoing surgery for paediatric and congenital cardiac disease survive to discharge from the hospital [355],[356],[357],[358],[359],[360],[361],[362],[363],[364],[365],[366],[367],[368],[369],[370],[371],[372],[373],[374],[375],[376],[377],[378],[379],[380],[381],[382],[383],[384],[385], although survival to discharge is lower in neonates (8.0% operative mortality).[355],[356],[357],[358],[359],[360],[361],[362],[363],[364],[365],[366],[367],[368],[369],[370],[371],[372],[373],[374],[375],[376],[377],[378],[379],[380],[381],[382],[383],[384],[385] Survival after surgery for congenital heart defects has increased over the past decade, especially for the most complex operations.[257],[355],[356],[357],[358],[359],[360],[361],[362],[363],[364],[365],[366],[367],[368],[369],[370],[371],[372],[373],[374],[375],[376],[377],[378],[379],[380],[381],[382],[383],[384],[385] The etiology of this improvement is obviously multifactorial, but the ability to compare and benchmark risk-stratified and risk-adjusted outcomes at individual programs to national aggregate benchmarks certainly facilitated these improved cardiac surgical outcomes over time.

This chapter will review progress that has been made and summarize the state of the art in eight domains of outcomes analysis and quality improvement.

1. Nomenclature: The first step in developing a database or registry to assess the outcomes and improve the quality of a medical or surgical subspecialty is to standardize the nomenclature or terminology so that one is “comparing apples to apples and oranges to oranges”.
2. Database: After the nomenclature is standardized, one can create a unfirm multi-institutional database or registry with standardized definitions and rules to keep track of a variety of data, including patient related factors (e.g., demographic data, preoperative factors, intraoperative factors, postoperative factors, and outcomes), procedure related factors, and even institution related factors; definitions and rules must be developed so that these data are uniformly captured.
3. Risk Adjustment: Case-mix can vary from program to program; and therefore, one must consider case mix while analyzing and reporting outcomes, utilizing strategies such as risk stratification and risk modelling.
4. Verification of the completeness and accuracy of the data: After standardizing the nomenclature, creating a database or registry with standardized definitions and rules, and developing strategies for risk adjustment, one must then assure that the data are correct, true, and believable, by implementing strategies to verify the completeness and accuracy of the data using techniques that may include (1) intrinsic data verification to rectify inconsistencies of data and missing elements of data, (2) site visits (or virtual site visits) with “Source Data Verification”, and (3) external verification of the data from independent databases or registries.
5. Collaboration across medical and surgical subspecialties: Caring for patients is a multi-disciplinary activity; and therefore, databases or registries designed to assess the outcomes and improve the quality of a medical or surgical subspecialty must include information from multiple medical and surgical subspecialties. In pediatric and congenital cardiac care, these subspecialties include, but are not limited to, the following fields: cardiac surgery, cardiology, anesthesia, critical care, neonatology, nursing, perfusion, advanced practice providers (APP’s, including physician assistants [PA’s] and nurse practitioners [ARNP’s]), respiratory therapists, physical therapists, occupational therapists, social workers, and many more. Data from each of these professions will contribute to the analysis of outcomes, the assessment of quality, and the improvement of quality.
6. Linking of databases and registries: It is possible to link together complementary databases using either probabilistic matching of records with shared indirect identifiers or deterministic matching of records with shared unique direct identifiers; such linked databases will answer complex and unique questions that each individual database cannot answer independently.
7. Longitudinal follow-up: The assessment of outcomes of medical and surgical therapies should encompass obtaining follow-up data for the entire life of the patient.
8. Assessment and improvement of quality: The ultimate goal of these activities is to assess and improve quality; the tools to achieve this goal can be created by (1) standardizing the nomenclature; (2) creating a database or registry with standardized definitions and rules; (3) developing strategies for risk adjustment, including risk stratification and risk modelling; (4) verifying the completeness and accuracy of the data using techniques that may include intrinsic data verification to rectify inconsistencies of data and missing elements of data, site visits (or virtual site visits) with “Source Data Verification”, and external verification of the data from independent databases or registries; (5) including information from multiple medical and surgical subspecialties; (6) linking together complementary databases using either probabilistic matching of records with shared indirect identifiers or deterministic matching of records with shared unique direct identifiers; and (7) obtaining follow-up data for the entire life of the patient. Such a database or registry will then span geographic, subspecialty, and temporal boundaries, and facilitate the assessment and improvement of quality.

Because a separate chapter can easily be written about each of these eight domains, a comprehensive reference list is provided for each domain, and highlights of each of the following eight domains of outcomes analysis and quality improvement are summarized:

1. Nomenclature[3],[4],[5],[6],[7],[8],[9],[10],[11],[12],[13],[14],[15],[16],[17],[18],[19],[20],[21],[22],[23],[24],[25],[26],[27],[28],[29],[30],[31],[32],[33],[34],[35],[36],[37],[45],[46],[48],[49],[50],[51],[52],[53],[57],[59],[62],[63],[70],[74],[75],[76],[78],[82],[85],[86],[87],[92],[93],[94],[96],[97],[98],[103],[110],[111],[112],[113],[114],[115],[116],[117],[118],[119],[120],[121],[122],[130],[144],[150],[151],[154],[155],[173],[182],[183],[184],[191],[192],[194],[195],[200],[212],[213],[214],[224],[225],[230],[231],[243],[275],[276],[287],[303],[349],[350]
2. Database[1],[2],[3],[4],[5],[6],[7],[8],[9],[10],[11],[12],[13],[14],[15],[16],[17],[18],[19],[20],[21],[22],[23],[24],[25],[26],[27],[28],[29],[30],[31],[32],[33],[34],[35],[36],[39],[40],[41],[42],[44],[45],[46],[53],[59],[61],[62],[63],[69],[70],[75],[77],[80],[82],[86],[87],[90],[92],[93],[94],[95],[99],[100],[101],[102],[103],[104],[105],[110],[111],[112],[113],[114],[115],[116],[117],[118],[119],[120],[121],[122],[125],[126],[129],[130],[133],[134],[135],[136],[137],[143],[145],[154],[155],[156],[160],[161],[163],[164],[165],[167],[169],[170],[172],[180],[187],[189],[190],[192],[193],[194],[198],[202],[203],[204],[205],[209],[210],[211],[212],[213],[214],[215],[216],[217],[224],[225],[226],[227],[228],[229],[230],[231],[232],[237],[239],[240],[241],[242],[244],[245],[246],[247],[248],[249],[250],[251],[253],[254],[255],[257],[259],[260],[261],[262],[263],[264],[265],[266],[267],[268],[269],[270],[271],[272],[273],[274],[275],[276],[279],[280],[281],[282],[283],[284],[285],[286],[288],[289],[290],[291],[292],[293],[294],[295],[296],[297],[298],[299],[300],[301],[302],[304],[309],[310],[311],[312],[313],[314],[316],[317],[318],[319],[321],[322],[323],[324],[325],[326],[327],[328],[329],[330],[331],[332],[333],[334],[335],[336],[337],[338],[339],[340],[341],[342],[343],[344],[345],[346],[348]
3. Risk Adjustment[38],[43],[44],[47],[54],[55],[56],[58],[60],[61],[63],[64],[65],[66],[70],[71],[72],[73],[79],[80],[81],[82],[83],[84],[86],[88],[89],[92],[93],[94],[106],[107],[123],[124],[129],[130],[131],[132],[186],[197],[199],[218],[220],[222],[223],[224],[233],[234],[235],[237],[238],[251],[258],[271],[272],[277],[305],[306],[308],[320],[347]
4. Verification of the completeness and accuracy of the data[67],[68],[70],[82],[86],[92],[93],[94],[108],[130],[224],[252],[315]
5. Collaboration across medical and surgical subspecialties[92],[93],[94],[95],[96],[97],[98],[99],[100],[101],[102],[103],[104],[105],[106],[107],[108],[109],[110],[111],[112],[113],[114],[115],[116],[117],[118],[119],[120],[121],[122],[130],[224],[228],[248],[252],[265],[300],[307],[323],[329],[330],[339],[340]
6. Linking of databases and registries[92],[93],[109],[127],[128],[146],[153],[171],[175],[176],[196],[207],[208],[224],[248],[269],[317],[318],[323],[331],[332],[334],[335],[339],[340]
7. Longitudinal follow-up[86],[91],[92],[93],[109],[127],[128],[146],[153],[166],[224],[228],[248],[278]
8. Assessment and improvement of quality [90],[92],[93],[97],[126],[133],[136],[138],[139],[140],[141],[142],[147],[148],[149],[152],[157],[158],[159],[160],[161],[162],[164],[165],[167],[168],[169],[170],[172],[174],[177],[178],[179],[180],[181],[185],[187],[188],[190],[193],[198],[201],[202],[204],[205],[206],[210],[211],[215],[216],[217],[219],[221],[222],[223],[224],[225],[226],[227],[229],[232],[236],[237],[238],[239],[240],[241],[242],[244],[245],[246],[247],[248],[249],[250],[251],[253],[254],[255],[256],[257],[261],[262],[263],[264],[266],[267],[270],[271],[272],[273],[274],[279],[280],[282],[283],[284],[285],[286],[288],[289],[290],[293],[294],[296],[297],[298],[300],[301],[302],[304],[309],[310],[311],[312],[313],[321],[322],[324],[325],[327],[328],[329],[333],[334],[336],[337],[338],[339],[340],[341],[342],[344],[345],[346]