Norwood Procedure

Overview

The Norwood procedure is a surgical operation typically performed on babies born with hypoplastic left heart syndrome (HLHS). This condition occurs when the left side of the heart is underdeveloped and cannot effectively pump oxygen-rich blood to the body. The surgery redirects the right side of the baby’s heart to take over this function, allowing it to send oxygenated blood throughout the body. In a normal heart, the left side handles this task, but the Norwood procedure compensates for the inadequacy of the left side in HLHS patients.

Post-surgery, the right ventricle continues to pump deoxygenated blood to the lungs while also taking on the additional role of pumping oxygenated blood to the rest of the body. Although this means that oxygenated and deoxygenated blood are not completely separated as they would be in a typical heart, the procedure significantly improves the delivery of oxygen to the baby’s cells and tissues. While not a perfect solution, it enhances the baby’s overall oxygenation and supports better growth and development.

3 Types of surgeries for HLHS

The three HLHS surgeries are as follows:

• The Norwood procedure is typically performed within the first two weeks after birth.
• The Glenn procedure is typically performed when the child is between 4 to 8 months old.
• The Fontan procedure is typically performed between 18 months and 5 years of age.

Reasons for undergoing the procedure

Babies diagnosed with hypoplastic left heart syndrome require early intervention, often within the first weeks of life, typically through procedures such as the Norwood operation. This surgery is critical because it allows the right ventricle to take on the combined workload of both ventricles, compensating for the underdeveloped left ventricle in these infants.

During the initial days after birth, the baby’s blood can naturally flow between the aorta and pulmonary artery via the patent ductus arteriosus, allowing the right ventricle to supply blood to both the lungs and the body. However, once this duct closes shortly after birth, the right ventricle can no longer effectively supply blood to the body.

Medication can temporarily keep the ductus arteriosus open. Nevertheless, the Norwood procedure serves as an interim solution, enabling the functional ventricle (typically the right one) to manage all pumping duties of the heart.

Some infants may not qualify for a Norwood procedure due to factors such as premature birth, small size for their gestational age (SGA), or other significant health challenges. In these cases, pulmonary artery bands may be used to regulate blood flow to the lungs and improve circulation to the body.

Risks

Complications from the Norwood operation include:

• Shunt failure or blockage.
• Delay in neurodevelopment.
• Swelling (stenosis) of the aorta or pulmonary arteries.
• Heart rhythm abnormalities, called arrhythmias.
• Impaired heart or heart valve performance.

Before the procedure

If your baby is diagnosed with hypoplastic left heart syndrome, they will receive medication shortly after birth to prevent the closure of the patent ductus arteriosus, a normal process. Keeping this duct open allows for increased blood flow through the heart until they undergo Norwood heart surgery.

In addition, a doctor may perform a septostomy to enlarge an opening between the two upper chambers of the heart (the right and left atria), improving the flow of blood from the lungs into the right side of the heart.

During the procedure

A Norwood procedure is a complex surgical operation involving several critical steps. Here is a simplified outline of what the surgeon will do:

• The surgeon begins by creating an opening between your baby’s left and right atria to allow blood to flow between them, enabling blood returning from the lungs to reach the right ventricle. Next, the surgeon connects the smaller aorta to the larger pulmonary artery and enlarges your child’s aorta using a patch. Subsequently, the improved aorta is connected to the right ventricle.
• Another aspect of the surgery involves placing a tube or shunt between your child’s aorta or another major artery and their pulmonary arteries. This can be a Blalock-Taussig (BT) shunt, which connects the aorta to the pulmonary arteries that carry blood to the lungs, or a Sano shunt, which links the right ventricle directly to the pulmonary arteries.
• During the Norwood operation, your child will be on cardiopulmonary bypass. This involves a machine that circulates oxygenated blood to their body and brain.

The Norwood procedure is a lengthy surgery, often lasting as long as a full workday.

After the procedure

After surgery, your baby will initially receive care in the Intensive Care Unit (ICU). They typically spend about a week there before moving to a regular hospital room.

During their stay, you’ll notice various tubes and equipment designed to provide necessary support. Your baby will have a chest bandage following the Norwood procedure.

While the surgery improves blood circulation, it doesn’t cure the underlying condition. Mixing of oxygenated and deoxygenated blood can still occur in their heart, which may result in a persistent bluish tint to their skin.

Your doctor will provide detailed instructions for caring for your baby at home. Many hospitals offer specialized clinics for follow-up care, often including a home monitoring program. It’s beneficial to find a program that provides comprehensive, multidisciplinary care throughout your child’s development into adulthood.

Outcome

Following surgery, your child will typically spend between seven to 21 days in the hospital, with a portion of this time in the intensive care unit.

In-hospital survival rates following the Norwood procedure are approximately 90%. Five-year survival rates range from 60% to 75%. Unfortunately, some children with HLHS may experience sudden fatal complications before they can undergo the second surgery.

Six years after surgery, about 60% of children survive without needing a heart transplant, a rate that remains stable at around 20 years post-surgery.

Babies with lower birth weight, premature birth, or other congenital disorders not related to the heart generally have a poorer prognosis following surgery.