Cyanotic Congenital Heart Defects
Cyanotic congenital heart defects are the most important group of defects necessitating surgical intervention in the neonatal period. In general, this group of defects is characterized by ductal dependency of pulmonary blood flow (or effective pulmonary blood flow) but with notable exceptions of truncus arteriosus (TrA) and obstructed total anomalous pulmonary venous return or connection (TAPVR).
Cyanotic heart defects should be considered and ruled out or confirmed in any newborn presenting with cyanosis (see Chapter 80 for differential diagnosis of cyanosis in the neonate), although in a cyanotic neonate the response to oxygen, heart murmurs, chest roentgenogram, and electrocardiogram (ECG) can offer clues to cardiac defects and prompt further evaluation. The echocardiogram is the mainstay of diagnosis to delineate the morphology of the heart defect and plan intervention.
In the current era, fetal obstetric ultrasound and fetal echocardiography have enabled us to accurately diagnose congenital heart defects in the majority of neonates before they are born.
This modality has changed the presentation and management of this group of neonates. Because the diagnosis is often established before birth, the emphasis has shifted more on planning the management immediately after birth rather than establishing the diagnosis as in the past. However, a neonatologist still is faced with undiagnosed cyanotic newborns for which all clinical skills can be tested.
Once the diagnosis is confirmed, adequacy of pulmonary blood flow and systemic blood flow should be assessed and pulmonary venous obstruction should be ruled out. Physiology-specific therapeutic medical management should be instituted, and surgical treatment should be planned. In patients with low birth weight or in premature neonates, the approach to “wait and grow the patient” has not been promising. Waiting prior to surgical palliation increases preoperative complications without gaining any benefits.1 Even in this group of patients, an early correction is indicated, and in patients with functional single ventricles, appropriate early surgical palliation is indicated.
TOTAL ANOMALOUS PULMONARY VENOUS RETURN
Total anomalous pulmonary venous return (TAPVR) or connection is a cardiac malformation in which there is no direct connection between any pulmonary vein and the left atrium; rather, all the pulmonary veins connect to the right atrium or one of its tributaries. A patent foramen ovale (PFO) or atrial septal defect (ASD) is present and is necessary for survival after birth in all newborns with TAPVR.2
TAPVR is a rare congenital cardiac anomaly occurring in about 1.5% of children born with congenital heart defects. In addition, it can occur as an associated defect with many other congenital cardiac defects, especially in newborns with heterotaxy syndromes with single functional ventricles. Nevertheless, it is one of the few lesions necessitating urgent or emergent cardiac surgery in the neonatal period.