A complication is an event or occurrence that is associated with a disease or a healthcare intervention, is a departure from the desired course of events, and may cause, or be associated with, suboptimal outcome. A complication does not necessarily represent a breech in the standard of care that constitutes medical negligence or medical malpractice. An operative or procedural complication is any complication, regardless of cause, occurring (1) within 30 days after surgery or intervention in or out of the hospital, or (2) after 30 days during the same hospitalization subsequent to the operation or intervention. Operative and procedural complications include both intraoperative/intraprocedural complications and postoperative/postprocedural complications in this time interval.

The MultiSocietal Database Committee for Pediatric and Congenital Heart Disease has set forth a comprehensive list of complications associated with the treatment of patients with congenital cardiac disease, related to cardiac, pulmonary, renal, haematological, infectious, neurological, gastrointestinal, and endocrinal systems, as well as those related to the management of anaesthesia and perfusion, and the transplantation of thoracic organs. The objective of this manuscript is to examine the definitions of operative morbidity as they relate specifically to the renal system. These specific definitions and terms will be used to track morbidity associated with surgical and transcatheter interventions and other forms of therapy in a common language across many separate databases.

Although renal dysfunction and renal failure are known risks of congenital heart surgery, accurate estimates of the incidences of these complications are limited. This lack of knowledge is in part due to the lack of uniform definitions of these postoperative complications. The purpose of this effort is to propose consensus definitions for renal complications following congenital cardiac surgery so that collection of such data can be standardized. Clinicians caring for patients with congenital heart disease will be able to use this list for databases, quality improvement initiatives, reporting of complications, and comparing strategies for treatment.

It is universally agreed that efforts to improve quality benefit from the analysis of outcomes. Yet, it is challenging to compare results across institutions because factors other than performance also impact outcomes. Two factors that complicate the analysis of outcomes after congenital cardiac surgery are case-mix and random statistical variation. Case-mix refers to differences in the mix of patients and their risk-factors at different institutions that may cause some centres to have more frequent complications and lower survival regardless of their true performance. Random statistical variation refers to fluctuations in outcomes that occur at random and follow the laws of probability. A variety of statistical methods exist to address these issues and make provider comparisons more fair. We explain a few common approaches including stratification, regression analysis, and confidence intervals. Concepts are illustrated using artificial data from two hypothetical hospitals, as well as real data from a multi-institution registry.

Meaningful evaluation of quality of care must account for variations in the population of patients receiving treatment, or “case-mix”. In adult cardiac surgery, empirical clinical data, initially from tens of thousands, and more recently hundreds of thousands of operations, have been used to develop risk-models, to increase the accuracy with which the outcome of a given procedure on a given patient can be predicted, and to compare outcomes on non-identical patient groups between centres, surgeons and eras.

In the adult cardiac database of The Society of Thoracic Surgeons, algorithms for risk-adjustment are based on over 1.5 million patients undergoing isolated coronary artery bypass grafting and over 100,000 patients undergoing isolated replacement of the aortic valve or mitral valve. In the pediatric and congenital cardiac database of The Society of Thoracic Surgeons, 61,014 operations are spread out over greater than 100 types of primary procedures. The problem of evaluating quality of care in the management of pediatric patients with cardiac diseases is very different, and in some ways a great deal more challenging, because of the smaller number of patients and the higher number of types of operations.

In the field of pediatric cardiac surgery, the importance of the quantitation of the complexity of operations centers on the fact that outcomes analysis using raw measurements of mortality, without adjustment for complexity, is inadequate. Case-mix can vary greatly from program to program. Without stratification of complexity, the analysis of outcomes for congenital cardiac surgery will be flawed. Two major multi-institutional efforts have attempted to measure the complexity of pediatric cardiac operations: the Risk Adjustment in Congenital Heart Surgery-1 method and the Aristotle Complexity Score. Both systems were derived in large part from subjective probability, or expert opinion. Both systems are currently in wide use throughout the world and have been shown to correlate reasonably well with outcome.

Efforts are underway to develop the next generation of these systems. The next generation will be based more on objective data, but will continue to utilize subjective probability where objective data is lacking. A goal, going forward, is to re-evaluate and further refine these tools so that, they can be, to a greater extent, derived from empirical data. During this process, ideally, the mortality elements of both the Aristotle Complexity Score and the Risk Adjustment in Congenital Heart Surgery-1 methodology will eventually unify and become one and the same. This review article examines these two systems of stratification of complexity and reviews the rationale for the development of each system, the current use of each system, the plans for future enhancement of each system, and the potential for unification of these two tools.

Accurate, complete data is now the expectation of patients, families, payers, government, and even media. It has become an obligation of those practising congenital cardiac surgery. Appropriately, major professional organizations worldwide are assuming responsibility for the data quality in their respective registry databases.

The purpose of this article is to review the current strategies used for verification of the data in the congenital databases of The Society of Thoracic Surgeons, The European Association for Cardio-Thoracic Surgery, and The United Kingdom Central Cardiac Audit Database. Because the results of the initial efforts to verify data in the congenital databases of the United Kingdom and Europe have been previously published, this article provides a more detailed look at the current efforts in North America, which prior to this article have not been published. The discussion and presentation of the strategy for the verification of data in the congenital heart surgery database of The Society of Thoracic Surgeons is then followed by a review of the strategies utilized in the United Kingdom and Europe. The ultimate goal of sharing the information in this article is to provide information to the participants in the databases that track the outcomes of patients with congenitally malformed hearts. This information should help to improve the quality of the data in all of our databases, and therefore increase the utility of these databases to function as a tool to optimise the management strategies provided to our patients.

The need for accurate, complete and high quality Congenital Heart Surgery outcome data has never been more pressing. The public interest in medical outcomes is at an all time high and “pay for performance” is looming on the horizon. Information found in administrative databases is not risk or complexity adjusted, notoriously inaccurate, and far too imprecise to evaluate performance adequately in congenital cardiac surgery. The Society of Thoracic Surgeons and European Association for Cardio-Thoracic Surgery databases contain the elements needed for assessment of quality of care provided that a mechanism exists within these organizations to guarantee the completeness and accuracy of the data. The Central Cardiac Audit Database in the United Kingdom has an advantage in this endeavour with the ability to track and verify mortality independently, through their National Health Service.

A combination of site visits with “Source Data Verification”, in other words, verification of the data at the primary source of the data, and external verification of the data from independent databases or registries, such as governmental death registries, may ultimately be required to allow for optimal verification of data. Further research in the area of verification of data is also necessary. Data must be verified for both completeness and accuracy.

In 2000, The International Nomenclature Committee for Pediatric and Congenital Heart Disease was established. This committee eventually evolved into the International Society for Nomenclature of Paediatric and Congenital Heart Disease. The working component of this international nomenclature society has been The International Working Group for Mapping and Coding of Nomenclatures for Paediatric and Congenital Heart Disease, also known as the Nomenclature Working Group. The Nomenclature Working Group created the International Paediatric and Congenital Cardiac Code, which is available for free download from the internet at [http://www.IPCCC.NET].

In previous publications from the Nomenclature Working Group, unity has been produced by cross-mapping separate systems for coding, as for example in the treatment of the functionally univentricular heart, hypoplastic left heart syndrome, or congenitally corrected transposition. In this manuscript, we review the nomenclature, definition, and classification of heterotaxy, also known as the heterotaxy syndrome, placing special emphasis on the philosophical approach taken by both the Bostonian school of segmental notation developed from the teachings of Van Praagh, and the European school of sequential segmental analysis. The Nomenclature Working Group offers the following definition for the term “heterotaxy”: “Heterotaxy is synonymous with ‘visceral heterotaxy’ and ‘heterotaxy syndrome’. Heterotaxy is defined as an abnormality where the internal thoraco-abdominal organs demonstrate abnormal arrangement across the left-right axis of the body. By convention, heterotaxy does not include patients with either the expected usual or normal arrangement of the internal organs along the left-right axis, also known as ‘situs solitus’, nor patients with complete mirror-imaged arrangement of the internal organs along the left-right axis also known as ‘situs inversus’.” “Situs ambiguus is defined as an abnormality in which there are components of situs solitus and situs inversus in the same person. Situs ambiguus, therefore, can be considered to be present when the thoracic and abdominal organs are positioned in such a way with respect to each other as to be not clearly lateralised and thus have neither the usual, or normal, nor the mirror-imaged arrangements.”

The heterotaxy syndrome as thus defined is typically associated with complex cardiovascular malformations. Proper description of the heart in patients with this syndrome requires complete description of both the cardiac relations and the junctional connections of the cardiac segments, with documentation of the arrangement of the atrial appendages, the ventricular topology, the nature of the unions of the segments across the atrioventricular and the ventriculoarterial junctions, the infundibular morphologies, and the relationships of the arterial trunks in space. The position of the heart in the chest, and the orientation of the cardiac apex, must also be described separately. Particular attention is required for the venoatrial connections, since these are so often abnormal. The malformations within the heart are then analysed and described separately as for any patient with suspected congenital cardiac disease. The relationship and arrangement of the remaining thoraco-abdominal organs, including the spleen, the lungs, and the intestines, also must be described separately, because, although common patterns of association have been identified, there are frequent exceptions to these common patterns. One of the clinically important implications of heterotaxy syndrome is that splenic abnormalities are common. Investigation of any patient with the cardiac findings associated with heterotaxy, therefore, should include analysis of splenic morphology. The less than perfect association between the state of the spleen and the form of heart disease implies that splenic morphology should be investigated in all forms of heterotaxy, regardless of the type of cardiac disease. The splenic morphology should not be used to stratify the form of disease within the heart, and the form of cardiac disease should not be used to stratify the state of the spleen. Intestinal malrotation is another frequently associated lesion that must be considered. Some advocate that all patients with heterotaxy, especially those with isomerism of the right atrial appendages or asplenia syndrome, should have a barium study to evaluate for intestinal malrotation, given the associated potential morbidity. The cardiac anatomy and associated cardiac malformations, as well as the relationship and arrangement of the remaining thoraco-abdominal organs, must be described separately. It is only by utilizing this stepwise and logical progression of analysis that it becomes possible to describe correctly, and to classify properly, patients with heterotaxy.

Congenitally corrected transposition is a complex cardiac lesion that is often associated with ventricular septal defect, obstruction of the outflow tract of the morphologically left ventricle, and abnormalities of the morphologically tricuspid valve.1,2 Nomenclature for this lesion has been variable and confusing.1 In this review, we define, and hopefully clarify this terminology. The lesion is a combination of discordant union of the atrial chambers with the ventricles, and the ventricles with the arterial trunks.1,2 In rare circumstances, discordant atrioventricular connections can be associated with concordant ventriculo-arterial connections. This malformation has been called “isolated ventricular inversion”. The term is less than precise, and the descriptive approach using the phrase “discordant atrioventricular connections with concordant ventriculo-arterial connections” is preferred, as discussed below.

The hypoplastic left heart syndrome encompasses a spectrum of cardiac malformations that are characterized by significant underdevelopment of the components of the left heart and the aorta, including the left ventricular cavity and mass. At the severe end of the spectrum is found the combination of aortic and mitral atresia, when the left ventricle can be close to non-existent. At the mild end are the patients with hypoplasia of the aortic and mitral valves, but without intrinsic valvar stenosis or atresia, and milder degrees of left ventricular hypoplasia. Although the majority of the patients are suitable only for functionally univentricular repair, a small minority may be candidates for biventricular repair.

The nature of the syndrome was a topic for discussion at the second meeting of the International Working Group for Mapping and Coding of Nomenclatures for Paediatric and Congenital Heart Disease, the Nomenclature Working Group, held in Montreal, Canada, over the period January 17 through 19, 2003. Subsequent to these discussions, the Nomenclature Working Group was able to create a bidirectional crossmap between the nomenclature initially produced jointly on behalf of the European Association for Cardio-Thoracic Surgery and the Society of Thoracic Surgeons, and the alternative nomenclature developed on behalf of the Association for European Paediatric Cardiology. This process is a part of the overall efforts of the Nomenclature Working Group to create a comprehensive and all-inclusive international system of nomenclature for paediatric and congenital cardiac disease, the International Paediatric and Congenital Cardiac Code. In this review, we discuss the evolution of nomenclature and surgical treatment for the spectrum of lesions making up the hypoplastic left heart syndrome and its related malformations. We also present the crossmap of the associated terms for diagnoses and procedures, as recently completed by the Nomenclature Working Group.

The nomenclature and classification of patients with a functionally univentricular heart has been debated for decades. We review here the approach taken for dealing with this group of patients by the International Working Group for Mapping and Coding of Nomenclatures for Paediatric and Congenital Cardiac Disease. We discuss the approach of this Nomenclature Working Group in the context of other historical and contemporary ideas about this topic.

There are many reasons for seeking to create a global database with which to record the outcomes of therapy for congenital heart disease. Such a database can function as a tool to support a variety of purposes: