The Norwood operation is a procedure to save newborns with congenital hypoplastic left heart syndrome. It is a three-stage surgical procedure, the first stage of which is performed in the first few days of life. The second stage follows several months later and the third Norwood stage is usually performed between one and a half and three years of age.
Below you will find more information on this surgical procedure and specialists for Norwood surgery.
The Norwood operation is used to save newborns with HLHS.
Hypoplastic left heart syndrome (abbreviated HLHS) is a rare but serious malformation of the heart. It accounts for around 1.6% of all congenital heart defects. Children born with this heart defect die in the neonatal period if no immediate intervention is taken. HLHS is genetically determined.
In HLHS, the left side of the heart, i.e. the left atrium and left ventricle, is underdeveloped. The first section of the main artery(aorta) is also underdeveloped or completely dysfunctional. The ascending part up to and including the aortic arch is usually affected. The two heart valves of the left heart are also underdeveloped:
These valves are severely narrowed or completely blocked and underdeveloped.
The anatomy of a healthy heart © bilderzwerg | AdobeStock
In principle, the Norwood operation means converting the heart to a single-chamber system. As the left side of the heart cannot fulfill its function, the right side has to take over.
The right ventricle then supplies the body with oxygen-rich blood from the pulmonary circulation. In a normally developed heart, this is the task of the left heart.
This operation was developed by William Norwood in the early 1990s. The first patients treated in this way have already reached the age of around 30.
The Norwood operation is not a single intervention, but a three-stage surgical procedure:
The first two stages of the Norwood operation are performed on the non-beating heart. The heart must therefore be stopped. A heart-lung machine is then used to supply the body with oxygen.
Normally, the pulmonary circulation and the systemic circulation are separate. Both meet in the heart, from where the oxygen-rich blood is pumped from the lungs into the body.
Unborn children cannot yet breathe in their mother's body. This is why the systemic and pulmonary circulations are still connected in the first hours or days after delivery. The short circuit between the two circulatory systems is maintained by
upright.
After birth, the body gradually breaks down these short-circuit connections. In newborns with a healthy heart, this is important for the oxygen supply to the circulatory system.
For children with HLHS, however, the gradual separation of the pulmonary circulation from the systemic circulation is life-threatening. The underdeveloped side of the left heart cannot provide the necessary pumping capacity.
The human cardiovascular system with a healthy heart © LuckySoul | AdobeStock
The first stage of Norwood surgery is therefore necessary in the first few days of life . The heart surgeon then creates an artificial connection between the pulmonary and systemic circulation.
The surgeon works on the non-beating heart. He first reconstructs the atrophied section of the aorta, including the aortic arch. He also creates an artificial connection between the aorta and the pulmonary artery(pulmonary artery).
The heart surgeon shuts down the natural connection between the two circulatory systems that was still present at birth. He also removes the septum between the two atria.
The right ventricle now takes over the pumping function for the pulmonary and systemic circulation.
However, the oxygen-rich blood from the lungs still mixes with the "used", carbon dioxide-rich blood from the entire body. Due to the suboptimal supply of oxygen, children therefore tend to suffer from a purple-bluish discoloration of the skin.
In the second stage of the Norwood operation , the heart surgeon relieves the right ventricle.
The heart surgeon also performs the second stage of the Norwood operation on an open, non-beating heart. He cuts the superior vena cava and connects it directly to the pulmonary artery (so-called Hemi-Fontan or Glenn anastomosis).
The connection between the aorta and the pulmonary artery implanted in the first stage is removed again.
He then inserts a patch into the right ventricle. This prevents deoxygenated blood from the lower body from reaching the lungs in an uncontrolled manner.
The operation relieves some of the pressure on the right ventricle. However, deoxygenated blood still mixes with oxygen-rich blood from the lungs via the inferior vena cava. The oxygen supply is therefore still not optimal.
The final procedure ensures a complete separation between oxygen-rich and oxygen-poor blood.
In some specialist clinics, heart surgeons perform the third and final stage of the Norwood operation without using the heart-lung machine.
The surgeon now also connects the inferior vena cava to the pulmonary artery. Now the exhausted, carbon-dioxide-rich blood can no longer mix with oxygen-rich blood.
The difference to the normal heart is that the right ventricle takes over the function of the left ventricle. It pumps oxygen-rich blood from the lungs directly into the aorta. The deoxygenated blood from the upper and lower body reaches the pulmonary arteries directly without pressure. The healthy heart pumps the blood from the right ventricle to the lungs. No pumping is necessary after the Norwood operation.
It is not yet possible to make a reliable statement about the life expectancy of those affected. The surgical procedure has only been used for just under 30 years.
However, experience has shown that those affected can lead an (almost) normal life. It is possible to participate in popular sports without having to perform at peak physical performance. There is much to suggest that patients have a normal life expectancy.
