Treatment for hypoplastic left heart syndrome requires either a three-step surgical procedure called staged palliation or a heart transplant. Staged palliation is considered one of the major achievements of congenital heart surgery in recent years. The survival rate for children at age 5 is about 70 percent and most of these children have normal growth and development. This three-step surgery procedure is designed to create normal blood flow in and out of the heart, allowing the body to receive the oxygenated blood it needs.
The Norwood procedure is a three-stage heart surgery to create a new functional systemic circuit in patients with hypoplastic left heart syndrome. Stage 1 of the Norwood procedure involves atrial septectomy and transection and ligation of the distal main pulmonary artery.
This procedure is performed shortly after birth. It converts the right ventricle into the main ventricle pumping blood to both the lungs and the body. The main pulmonary artery and the aorta are connected and the main pulmonary artery is cut off from the two branching pulmonary arteries that direct blood to each side of the lungs. Instead, a connection called a shunt is placed between the pulmonary arteries and the aorta to supply blood to the lungs.
Stage 2 (Bi-directional Glenn Operation)
This operation usually is performed about six months after the Norwood to divert half of the blood to the lungs when circulation through the lungs no longer needs as much pressure from the ventricle. The shunt to the pulmonary arteries is disconnected and the right pulmonary artery is connected directly to the superior vena cava, the vein that brings deoxygenated blood from the upper part of the body to the heart. This sends half of the deoxygenated blood directly to the lungs without going through the ventricle.
Stage 3 (Fontan Operation)
This is the third stage, usually performed about 18 to 36 months after the Glenn. It connects the inferior vena cava, the blood vessel that drains deoxygenated blood from the lower part of the body into the heart, to the pulmonary artery by creating a channel through or just outside the heart to direct blood to the pulmonary artery. At this stage, all deoxygenated blood flows passively through the lungs.