Critical Congenital Heart Disease · CCHD

Description

Critical congenital heart disease (CCHD) is a group of structural heart defects present at birth that require surgical or catheter-based intervention in the first weeks or months of life. CCHD is not a single-gene disorder. It covers a defined set of lesions that share a common operational feature, severe ductal-dependent or hypoxemic physiology that becomes life-threatening once the ductus arteriosus closes. The lesions on the screening target list include hypoplastic left heart syndrome, pulmonary atresia with intact septum, tetralogy of Fallot, total anomalous pulmonary venous return, transposition of the great arteries, tricuspid atresia, and truncus arteriosus. Several additional cyanotic and obstructive lesions are detected by the same screen.

Combined incidence of the seven primary screening targets is approximately 2 per 1,000 live births, with all CCHD lesions together near 3 per 1,000. Genetic etiology is heterogeneous. A subset of cases is associated with chromosomal disorders such as 22q11.2 deletion syndrome, trisomy 21, and Turner syndrome. Most cases are sporadic with multifactorial inheritance.

CCHD is screened by pulse oximetry on the right hand and either foot before nursery discharge, typically after 24 hours of life. The Secretary of Health and Human Services added pulse-oximetry screening for CCHD to the Recommended Uniform Screening Panel in September 2011, after the work of the CCHD workgroup chaired by Alex Kemper and the algorithm validation reported by Kemper et al. (Pediatrics, 2011). All 50 states implemented some form of CCHD screening within the following years. A failed screen prompts echocardiography. Prenatal detection by fetal echocardiography identifies a meaningful share of cases before birth, especially hypoplastic left heart syndrome, and shifts delivery to a center with cardiac surgical capacity.

Treatments to date

Treatment is procedural, not pharmacologic. Initial stabilization of a ductal-dependent lesion uses prostaglandin E1 infusion to keep the ductus arteriosus open until anatomy is defined and a surgical or catheter plan is in place. Definitive repair is determined by anatomy and physiology.

For two-ventricle lesions such as transposition of the great arteries, total anomalous pulmonary venous return, tetralogy of Fallot, and truncus arteriosus, surgical repair in the neonatal or early-infancy period restores in-series circulation. The arterial switch operation, developed by Adib Jatene and reported in 1976, replaced the older Mustard and Senning atrial-switch repairs as standard for transposition. Tetralogy of Fallot repair is typically performed in the first year of life.

For single-ventricle lesions such as hypoplastic left heart syndrome, tricuspid atresia, and pulmonary atresia with intact septum and severe right-ventricular hypoplasia, staged univentricular palliation is the standard pathway. Stage one is the Norwood procedure or a hybrid stage one with bilateral pulmonary artery bands and ductal stenting, performed in the neonatal period. Stage two is the bidirectional Glenn shunt, typically between four and six months of age. Stage three is the Fontan completion, typically between two and four years of age. The Norwood procedure was first reported by William Norwood in 1980 and refined over subsequent decades. Heart transplantation is considered when palliation fails or when anatomy cannot be palliated.

Catheter-based interventions, including balloon atrial septostomy for transposition and balloon valvuloplasty for critical aortic or pulmonary stenosis, are part of routine neonatal management at cardiac centers. Long-term care continues into adulthood through specialized adult congenital heart disease programs, with surveillance for arrhythmia, ventricular dysfunction, Fontan-associated liver disease, and protein-losing enteropathy.