Single Ventricle Surgery

Most children with single ventricle heart defects need a series of three operations to treat their condition. The goal of these surgeries is to enable one ventricle to do the work normally done by two ventricles. The Single Ventricle Program at Boston Children’s Hospital provides care for all types of single ventricle defects, including all of the surgeries listed below. And The Fontan Clinic at Boston Children’s offers holistic, individualized care for patients of all ages who have had the Fontan procedure.

The stage 1 procedure, also known as the Norwood procedure, is one of the most complex congenital heart surgeries performed. The Norwood procedure was developed and first performed at Boston Children’s Hospital in 1979 by Dr. William Norwood. Boston Children’s performs about 40 to 50 stage 1 procedures each year, and we have a dedicated team of neonatal cardiac surgeons who specialize in this procedure.

The stage 1 procedure begins with an incision in the front of the chest to expose the heart, lungs, and great vessels (pulmonary artery and aorta).

The next step is to place your baby on heart-lung bypass. This is a specialized machine that provides blood flow and oxygen to your baby during the operation. While your baby is on this machine, a dedicated team of specialists, called perfusionists, make sure your baby’s brain and other organs get enough oxygen. Bypass takes place through small special tubes, called cannulas, which are placed into the heart to drain blood returning to the heart (so that it is empty and can be opened to perform the operation), give it oxygen, and return it back into the body.

The stage 1 procedure has three main steps:

Step 1: Reconstruction of the aorta

The first step of the operation includes a reconstruction of the aorta, so that all of the blood coming out of the heart can go to the body, as well as supply blood flow to the coronary arteries. In this part of the operation, the root of the pulmonary artery (now called the neo-aorta) is connected to the aorta (now called the native aorta). The remainder of the aortic arch (which often is very small) is then attached to these two vessels and its size is significantly expanded using a patch of tissue. This is the most technically challenging and complex part of the operation.

Step 2: Create a source of pulmonary blood flow

In the second part of the procedure, a new source of blood flow is needed to get blood to the lungs. There are two common techniques to do this. One technique is to connect a tube, known as the Blalock-Taussig-Thomas (BTT) shunt, from the aorta to the pulmonary artery. The other method is to connect a tube, known as the Sano or right ventricle to pulmonary artery conduit, from the ventricle to the pulmonary artery.

Step 3: Remove the atrial septum

In the third step, the wall separating the right and left side of the atrium (the atrial septum) is usually cut out completely.

Your baby will then be weaned carefully from the bypass machine and started on medications to help the heart squeeze better. Once the operation is complete, the team will perform a complete echocardiogram to make sure the operation looks as expected. A few additional catheters will be placed into the heart for monitoring and a few drains placed into the chest and a dressing placed over the chest.

Sometimes, a child’s condition may make it risky to use heart-lung bypass. For example, a child may be premature, have bleeding in the brain, or have severe lung disease. In cases like these, your care team may consider an alternative to stage 1 that does not require heart-lung bypass, but that keeps your child safe after birth. The key features of this procedure include:

• Limiting the amount of blood flow going to each lung by placing a restricting suture or band on each of the pulmonary arteries
• Maintaining a pathway for blood to get from the right ventricle to the aorta through the patent ductus arteriosus using a long-term medication (prostaglandin) infusion or using a stent

Although this is a technically somewhat less complex approach than stage 1, there are drawbacks. In most cases, all the stage 1 steps will still have to take place at a later date — and the future operations become more complicated. Nonetheless, the hybrid approach may allow valuable time for recovery and growth in certain situations.

Between the stage 1 and stage 2 surgeries, your baby’s heart requires extra monitoring to prevent complications. During this time, our Single Ventricle Home Monitoring Program will give you goals for your baby’s growth and oxygen saturation levels and provide monitoring equipment for your baby. You’ll also get information on when to call. Your baby is followed closely by a team of doctors and nurses.

The goal for the next stage is to deliver oxygen to the body more efficiently. During the second surgery, the blood coming back from the head and arms is redirected and connected directly to the lung vessels. This operation is called the bidirectional Glenn (or superior cavopulmonary connection). The Glenn surgery also involves removal of any prior shunt to the lungs. The vast majority of children do well after the Glenn surgery.

The third stage of the "single ventricle" pathway is called Fontan surgery. During this procedure, the blood from the lower half of the body (inferior vena cava) is diverted directly to the lungs. For the first time, all the blood from the head, arms, and legs now flows passively to the lungs. After the Fontan, blood flows from the heart to the body, and then returns to the lungs directly to receive oxygen again. This circulation most closely resembles a normal heart, despite only having one pump.

There have been many modifications to the Fontan procedure. Two modern techniques include the extracardiac Fontan and the lateral tunnel Fontan. The extracardiac Fontan is a tube that is connected from the inferior vena cava to the pulmonary arteries. In the lateral funnel Fontan, there is a pathway within the heart that allows blood from the legs to drain into the lungs. For most Fontan procedures, a small hole (or fenestration) is created between the Fontan pathway and the heart. This hole serves a helpful “pop-off” during the post-operative period or when pressure is high in the lungs (such as during a bad cold or respiratory infection).

While the most common approach for treating newborns with a single ventricle heart is with the three surgeries ending with the Fontan operation, in some cases our surgeons can use new procedures and innovative technology to achieve biventricular circulation. This involves preparing the left side of the heart to function independently, so a single ventricle heart can be converted into two functioning ventricles. In some situations, this repair can be the initial procedure, but in others, a series of procedures may be used to rehabilitate the small ventricle before converting the heart to biventricular circulation. Our Complex Biventricular Repair Program can assess if your child might be a candidate for this surgery and offer you a customized evaluation and care plan.