The Norwood procedure is the first in a series of three open-heart surgeries that gradually improve certain heart defects that are present at birth (congenital heart disease). It is most often used to treat congenital defects in which one or both of the lower chambers of the heart (ventricles) are defective. The Norwood procedure cannot cure the underlying heart defects, but may enable young patients to remain healthy until the follow-on surgeries are performed. These surgeries include the Fontan procedure. However, the term "Norwood procedure" is sometimes used to refer to all three stages of the surgeries together.

 

Each of the three surgeries is done at a different age, beginning from infancy and continuing into the toddler years. The first two surgeries (Stages I and II) are used to temporarily relieve blood flow problems to and from the lungs. The third surgery (Stage III) is used to further improve circulation.

When all three surgeries are completed, the Norwood procedure re-routes the blood flow around some of the defective areas of the heart by creating new pathways for blood circulation to and from the lungs. Despite the complexity of the procedure, many children go on to live a relatively normal lifestyle after completing all three stages.

The most common heart defects that are treated by the Norwood procedure are:

The Norwood procedure is the first in a series of three open-heart surgeries that gradually improve specific life-threatening forms of congenital disease heart in which one or both of the lower chambers of the heart (ventricles) are defective. The three surgeries are done at three different ages, which are as follows:

The term "Norwood procedure" is sometimes used to refer to all three stages of the surgeries together.

Some of the life-threatening heart defects that may be treated by the Norwood procedure include:

The Norwood procedure helps to re-route blood flow to and from the lungs, keeping the heart functioning and oxygen-rich blood flowing to the body until all three surgeries are complete. It may also require reconstructing the aorta. 

The complete three-stage procedure can almost always be performed, and it offers great hope to the vast majority of infants who would probably not survive a month without it.

If the left ventricle is defective and the right ventricle is relatively healthy, the Norwood procedure turns the right ventricle into the main pumping chamber of the heart. This is accomplished by connecting the aorta and the pulmonary artery with a vein graft from elsewhere in the body or synthetic materials such as Dacron or Gore-Tex. This new pathway between the aorta and the pulmonary artery is called a Blalock-Taussig shunt.

One of the original shunts used for this procedure was known as a Blalock-Taussig shunt, which connected one of the arteries in the arm directly to pulmonary artery. This has been replaced with a modified Blalock-Taussig shunt, which uses synthetic material and avoids the need to reroute the blood supply to the arm. Newer modifications include the Sano shunt, which connects the right ventricle and pulmonary artery. Many centers have adopted this new approach because it appears to help patients remain stable immediately after the surgery.

A component of the stage I Norwood procedure is reconstructing the aorta by sewing the base of the pulmonary artery (main pulmonary artery) to the underdeveloped base of the aorta. Other segments of the aorta may require synthetic material to enlarge the vessel. The pulmonary arteries that go the lungs (right and left pulmonary arteries) are completely separated from their base and receive all of their blood flow from either the Blalock-Taussig shunt or the Sanno procedure.  The valve of the pulmonary artery will function as the aortic valve for the rest of the patient's life.

Under normal circumstances, the blood in the right ventricle is oxygen-poor blood returning from the body. However, in addition to creating a shunt during the first stage of the procedure, the physician may also cut away the septum between the heart’s two upper chambers (atria). This allows oxygen-rich blood returning from the lungs to the left atrium to mix with the oxygen-poor blood in the right atrium. In turn, this oxygen-rich blood passes into the right ventricle and is pumped out to both the lungs and the rest of the body via the pulmonary artery and the newly established shunt.

After the first stage of the procedure, the right ventricle becomes the main or only chamber responsible for pumping blood to the lungs and to the tissues and organs of the body.

A newer procedure, termed a hybrid Norwood procedure, has also been developed that avoids use of the heart-lung machine in patients with a left ventricle defect. During this less-invasive procedure, physicians open the chest briefly to gain access to the pulmonary arteries and aorta. They then place restrictive bands around the pulmonary arteries to narrow them and raise the blood pressure in the right side of the heart. Next, they connect the aorta to the right side of the heart with a stent. This creates a right-to-left shunt in which the high blood pressure in the right side of the heart forces blood through the stent and into the aorta. This procedure can replace the first stage of the three-stage process in some patients, allowing them to strengthen before the second and third stages are performed. This procedure is still being developed and is still not widely undertaken.

Stage II of the Norwood procedure, also known as the hemi-Fontan or bidirectional Glenn procedure, is typically performed when the infant is between three and nine months of age. It connects the superior vena cava (the large vein that collects oxygen-poor blood from the upper part of the body) directly to the pulmonary artery. This new pathway allows oxygen-poor blood from the head and upper body to flow directly to the lungs, bypassing the heart and defective ventricle. Once the blood receives fresh oxygen in the lungs, it goes back to the heart and is pumped out to the body.

At this stage, the Blalock-Taussig shunt or Sanno procedure is removed because oxygen-rich blood can now circulate throughout the body. This is a crucial step in avoiding the mixing of red (oxygen-rich) and blue (oxygen-poor) blood. However, the complete operation is only half-finished because the oxygen-poor blood returning from the lower part of the body has not yet been re-routed. After this stage, the baby will still have a bluish tinge, but will be better able to handle infection and other problems.

Stage III of the Norwood procedure is also known as the Fontan procedure. It is performed between 18 months and four years of age. In this stage, both the right atrium and the inferior vena cava (the major vein that collects oxygen-poor blood from the lower part of the body) are connected to the pulmonary artery. Now the oxygen-poor blood from the upper and lower body flows directly to the lungs bypassing the heart completely. Meanwhile, oxygen-rich blood flow from the lungs will be diverted through the single functioning ventricle and pumped out to the body.

The resulting oxygen-rich blood circulating to the entire body will result in a normal, healthy skin tone. Depending upon the nature and severity of the heart defects, some children may be healthy enough after stage II that stage III is not necessary.

One variation of Stage III is known as the lateral tunnel Fontan, or a total cavopulmonary connection (TCPC). In this procedure, a patch (made of either synthetic materials or the patient's own tissue) is used to create a tunnel within the right atrium. The tunnel links two major veins, the superior vena cava and the inferior vena cava, and is then connected to the pulmonary artery. A slight variation of the lateral tunnel Fontan is the fenestrated Fontan. In this procedure, a hole is made in the tunnel. This hole allows for decompression of the blood into the right atrium when the pressure within the tunnel gets too high. Later, if the patient has stabilized, the hole can be closed with either a stitch or a cardiac catheterization procedure. Many of these holes will close on their own with time.

When the Norwood procedure is complete, oxygen-poor blood can move directly from the veins to the lungs without having to be pumped by a defective ventricle, and oxygen-poor and oxygen-rich blood are no longer mixed. 

Similarly, oxygen-rich blood will be pumped to the body by the healthy ventricle. In the case of total cavopulmonary connection (TCPC), the creation of this tunnel lessens the amount of turbulence and inefficient blood flow that occurs.

The recovery from the Norwood procedure can be complicated due to the complexity of the surgery. Most children remain in the hospital for three to four weeks. A smaller percentage may continue to experience problems in the first few months of life.

This procedure has a number of side effects. For example, there is increased pressure in the veins because only one ventricle is pumping in the heart. As a result, the body may retain fluid (edema), and there may be some facial puffiness. Fluid may also build up in the stomach or chest. To relieve the extra pressure, a hole is sometimes left in the lateral tunnel to the right atrium.

The Norwood operation is considered a complex procedure but survival after each of the three stages of surgery is 80 percent or higher. Long-term survival at five years of age is 70 percent. Once they have gone through all three stages, most children go on to live fairly normal lives, although they must continue with close medical management.

However, there are problems that may cause trouble for some patients in both the short and long terms. Up to 40 percent of patients who have had the Fontan operation experience significant arrhythmias over the long term. Those patients require careful follow-up therapy and medical management for this potentially dangerous problem. Another 13 percent develop a syndrome called protein-losing enteropathy in which excessive protein is lost through the gastrointestinal tract, along with symptoms of heart failure. These patients require close medical management throughout their lives.

Since the Norwood operation and the Fontan procedure have only been successfully performed widely for slightly over twenty years, most of the oldest patients are only in their early twenties.

Preparing questions in advance can help patients to have more meaningful discussions with their physicians regarding their conditions. Parents may wish to ask their doctor the following questions related to the Norwood procedure for their child:

1. Which type of heart defect does my child have?
   
   
2. What are the medical problems associated with this defect?
   
   
3. Is my child a candidate for the Norwood procedure?
   
   
4. How soon should my child begin the first stage of this procedure?
   
   
5. How effective do you expect this procedure to be for my child?
   
   
6. Will my child require any further treatment or surgeries after the Norwood procedure?
   
   
7. At what age will my child receive the other surgeries?
   
   
8. What is the recovery period from these surgeries?
   
   
9. How will my child's health be over the course of the procedure?
   
   
10. What are the chances my child will not survive the procedure?
    
    
11. Will my child need to take medications between any of the stages?
    
    
12.  Will my child have any restrictions during the course of the surgeries?
    
    
13. How will this defect and surgery affect my child later in life?
    
    
14. How will my child’s heart function be monitored?
    
    
15. Can you recommend a support group for our family?
    
    
16. Should I have a higher level ultrasound during any future pregnancies to see if the fetus has a significant heart problem?
    
    
17. Are there any genetic conditions that should be checked for associated with my baby's condition?