ABSTRACT

Cyanotic congenital heart defects, as a group, constitute up to 20 to 25% of all congenital heart defects. In cyanotic heart defects, the arterial oxygen desaturation is secondary to right to left shunting at the atrial, ventricular, or great artery level or because of transposition of the great arteries in which the deoxygenated blood recirculates through the body. In the latter group, balloon and/or blade atrial septostomy may be useful in augmenting admixture at the atrial level. These procedures have been described elsewhere in this book and will not be dealt with in this chapter. In the former group, obstruction to pulmonary blood flow by a stenotic or atretic pulmonary valve is an integral part of the cardiac malformation causing right to left shunt. The most common type of defect in this group is tetralogy of Fallot. Other defects include transposition of the great arteries, double outlet right (or left) ventricle, single ventricle, tricuspid atresia, ventricular inversion (corrected transposition of the great arteries), and other types of univentricular hearts, all with non-restrictive interventricular communication and severe pulmonary valve stenosis. These patients usually present with symptoms in the neonatal period or early in infancy. The degree of cyanosis and the level of hypoxemia determine the symptomatology. Physical findings and laboratory data (chest X-ray, electrocardiogram, and echocardiogram) depend upon the defect complex and are reasonably characteristic for each defect. The majority of cyanotic heart defects with pulmonary oligemia can be surgically treated. Total surgical correction may not be possible in some patients because of anatomic complexity. But yet, they may require palliation to augment pulmonary blood flow and to improve systemic arterial desaturation. Surgical aortopulmonary shunts have conventionally been utilized in these situations. Since the introduction of transluminal balloon dilatation techniques in children by Kan et al,1 we and others2-5 have utilized balloon pulmonary valvuloplasty to augment pulmonary blood flow instead of systemic to pulmonary artery shunt and successfully relieved pulmonary oligemia and systemic arterial hypoxemia.