Improving the quality of surveillance data on congenital heart defects in the Metropolitan Atlanta Congenital Defects Program

BACKGROUND: One of the challenges in epidemiologic studies of congenital heart defects (CHDs) has been the lack of a current, standard nomenclature and classification system. Recently such a standard nomenclature became available from the Society of Thoracic Surgeons (STS) Congenital Heart Surgery Database. This study reports the classification of cases of CHDs in a birth defects surveillance database using modified STS nomenclature. METHODS: Records of infants and fetuses in the Metropolitan Atlanta Congenital Defects Program delivered during 1968-2003 with CHD diagnoses were reviewed by a team of pediatric cardiologists. The cases were assigned one or more STS codes and subsequently grouped into successively broader levels of aggregation. Aggregation was based on presumed morphogenetically similar developmental mechanisms. RESULTS: There were 12,639 cases reviewed, of which 89% had a single, primary STS code. Structural CHDs were found in 7,749 infants, while 4,890 were considered to have structurally normal hearts. Application of clinical CHD nomenclature improved the clinical accuracy of surveillance data by eliminating normal physiologic variants and obligatory shunt lesions. Classification also aggregated specific CHDs into groups appropriate for research and surveillance. CONCLUSIONS: Application of a current, standard CHD nomenclature and classification system to cases in a birth defects surveillance database improves the specificity of cardiac diagnoses and allows for the development of a flexible case aggregation system for monitoring of CHD prevalence.