Congenital Heart Surgery Nomenclature and Database Project: hypoplastic left heart syndrome

Hypoplastic left heart syndrome (HLHS) encompasses a spectrum of structural cardiac malformations that are characterized by severe underdevelopment of the structures in the left heart-aorta complex, including the left ventricular cavity and mass. The severe end of the spectrum consists of aortic atresia and mitral atresia with a nonexistent left ventricle, whereas at the mild end patients have aortic valve and mitral valve hypoplasia without intrinsic valve stenosis, and milder degrees of left ventricular hypoplasia, recently described as hypoplastic left heart complex (HLHC). Although the overwhelming majority of the patients can only have a univentricular repair, a small minority of patients with HLHS, particularly those that are described as having HLHC, may be candidates for biventricular repair. In this paper, the extant nomenclature for HLHS is reviewed for the purpose of establishing a unified reporting system. The subject was debated and reviewed by members of the STS-Congenital Heart Surgery Nomenclature and Database Committee and representatives from the European Association for Cardiothoracic Surgery. Efforts were made to include all relevant nomenclature categories using synonyms where appropriate. A comprehensive database set is presented, which is based on a hierarchical scheme. Data are entered at various levels of complexity and detail that can be determined by the clinician. These data can lay the foundation for comprehensive risk stratification analyses. A minimum database set is also presented which will allow for data sharing, and would lend itself to basic interpretation of trends. Outcome tables relating diagnoses, procedures, and various risk factors are presented.