Hypoplastic Left Heart Syndrome

What are the Causes of HLHS?

The exact cause of HLHS is unknown. In the United States about 1,000 - 2,000 babies are born with HLHS each year. HLHS occurs more often in males (67%). Without surgery the child will not survive.

How Does a Normal Heart Function?

It is important to look at a normal heart and how it usually functions. Oxygen-poor (blue) blood returns to the right atrium from the body and travels to the right ventricle. It is then pumped through the pulmonary artery into the lungs where it receives oxygen. Oxygen-rich blood (red) returns to the left atrium from the lungs and passes into the left ventricle. The blood is then pumped out to the body through the aorta.

What Happens After the Baby is Born?

Since the baby is connected to the mother by the placenta before birth, infants with HLHS usually do not have any problems before or during delivery. Every baby is born with a ductus arteriosus. This is a blood vessel connecting the pulmonary artery and the aorta and allows oxygen-rich blood from the placenta to get to the baby's aorta. Usually, this blood vessel begins to close several hours to days after birth because the oxygen-rich blood now comes from the baby's lungs and it is no longer needed. Because the left ventricle and aortic arch are small and underdeveloped in babies with HLHS, they need the ductus arteriosus open. If the ductus closes, blood flow to the body becomes very low and they can become very ill and even die. A special medicine called prostaglandin is used to keep the ductus arteriosus open after birth. The medicine is given through a vein (by IV) until a procedure can be done to make a more permanent connection. One of the side effects of prostaglandin is apnea (pauses in the baby's breathing). If this occurs, it is sometimes necessary for a breathing tube to be placed and a breathing machine (ventilator) used to help the baby breathe.

If the baby is diagnosed before birth, the doctors and nurses will be prepared to take care of the baby shortly after birth. We do not deliver babies at Nationwide Children's Hospital. Delivery is arranged after speaking with your obstetrician at one of the maternity hospitals close to Nationwide Children's where a neonatalogist (a doctor who specializes in care of newborns) and a nursery specially designed to care for sick infants. Once the baby is stabilized at that hospital, they are transported the short distance to Nationwide Children's where they will be evaluated and cared for by The Heart Center team along with the neonatalogist.

How is HLHS Treated?

At Nationwide Children's, we offer a Single Ventricle program that is dedicated to the specific needs of these babies. We offer a number of treatment approaches, as well. One option, the Hybrid approach, was developed here, and it spares the baby open heart surgery until the baby is older and bigger. This procedure involves stenting of the patent ductus arteriosus (PDA) and banding the blood vessels to the lungs (pulmonary arteries). The baby returns at 4 to 6 months of age for the open heart surgery. Another option is called the Norwood. Here the surgeon connects the main blood vessels of the heart to permit blood to be pumped into the body. A tube is then connected from the blood vessel of the body (aorta) to the lung's blood vessel (pulmonary artery). The baby needs to return at 4 to 6 months of age for another surgery. Both of the above options require the baby to undergo further procedures and surgeries. Another possibility is a heart transplant.

Treatment Option 1: Hybrid approach

The Hybrid procedure is done in the Hybrid Suite. This specialized suite is a combined operating room and cardiac catheterization room. The child does not require heart-lung bypass for the first stage. It can be used on smaller weight infants and for families who request Alternative Non-Blood Medical Management. Stage 1 usually is done within the first week of life.

The Hybrid Stage I consists of:

1. Placement of bands around the right and left pulmonary arteries. This restricts blood flow to the pulmonary arteries, thereby balancing the circulation (to the lungs and the body). This also reduces the extra blood flow to the lungs.

2. Stenting of the PDA keeps the PDA open and maintains the connection to the aorta and the body's circulation.

3. There must be enough of a connection between the top two chambers of the heart (the atria) to provide open blood flow and mixing of the oxygen-rich and oxygen-poor blood. This can be done through a balloon atrial septostomy. In this procedure, a small tube (catheter) is passed across the septum between the two atria. Then a balloon on the end of the catheter is inflated and pulled back across the septum to enlarge the opening.

4. The goals of this first surgery stage include:

   1. Open blood flow through the PDA,

   2. An unblocked atrial septum 

   3. Balanced blood flow through the lungs and rest of the body.

Recovery: Hybrid Stage 1

The length of hospital stay can vary depending on the recovery of each child. The average length of stay is usually 2-4 weeks. After surgery, the baby will go to the cardiac intensive care unit for close monitoring. The baby may be on a breathing machine and will have intravenous line for monitoring and giving medicines. After the baby fully recovers from surgery the baby will be transferred to the regular cardiac floor. Sometimes babies who have heart surgery need to learn how to eat. This is because the baby may not have been fed by mouth before surgery and may tire more easily than a baby without a heart problem.

Follow Up

The pediatric cardiologist will be following your child very closely when you go home. It is very important that you bring your child to every scheduled appointment. These follow-up appointments are usually every 2 weeks. Some babies need to be followed more closely and are seen every week.

Comprehensive Stage II

This is an open heart surgery. It is done in the Operating Room and requires the use of the heart-lung bypass machine. It is usually done at 4 to 6 months of age. This includes the following:

1. Removal of the PDA stent and pulmonary artery bands. The pulmonary arteries are repaired and the atrial septum is enlarged with surgery.

2. The aortic arch is enlarged by disconnecting the small ascending aorta and connecting the aorta with the pulmonary root to make one large vessel. ( a new aorta)

3. The superior vena cava is connected to the pulmonary artery. This is called a Glenn shunt. This allows upper body blood flow to go directly to the pulmonary artery and the blood is not pumped through the heart first. This is a passive blood flow into the lungs. This procedure can not be done immediately after birth because the pulmonary resistance is too high to allow for passive blood flow to the lungs.

Recovery: Comprehensive Stage II

The length of hospital stay will vary. The average recovery time is 1-3 weeks. After surgery, the baby will go to the Cardiac Intensive Care Unit (CICU) and will have a chest tube and intravenous lines (IV's). The IV's will be used for monitoring and giving medicines. As long as the baby is on the breathing machine or needs to be watched closely, the baby will stay in the CICU. As the baby recovers he/she will be moved to the cardiac floor for the rest of the hospital stay. The average length of hospital stay is usually around 1 to 2 weeks.

Stage III: Fontan Procedure

The final surgery usually takes place around 2 years of age. This stage requires open heart surgery in the Operating Room. The child is on the heart-lung machine the same as Stage II. At this time the blood from the lower part of the body that goes back to the heart through the inferior vena cava is routed to the pulmonary artery directly. This makes all of the blood returning from the body a more “passive blood flow”. After the final surgery is completed, the blood flow from the upper body will return to the lungs by the superior vena cava connection. Blood will reach the lungs from the lower body by the inferior vena cava connection.

Recovery: Stage III

Recovery after surgery will be similar to the Stage II procedure. One important difference is that the child may have more than one chest tube to drain fluid from around the lung. Now all of the blood from the body is returning to the lungs through a “passive route” that requires a higher pressure. Therefore, fluid can leak out around the lungs and needs to be drained. Sometimes these chest tubes need to stay in for a longer time to drain this fluid. The child can be recovering on the regular cardiac floor and is encouraged to be out of bed and playing at this time. Length of stay varies from one to three weeks.

Treatment Option 2: Traditional Norwood

The traditional first stage approach for HLHS is an operation commonly known as the Norwood procedure, named after the physician who pioneered the repair. The repair requires the use of the bypass or heart-lung machine.

The Norwood repair consists of:

1. Placement of a shunt or pathway between the aorta and pulmonary artery. The shunt is called a modified Blalock-Taussig Shunt (BT Shunt).

2. Atrial septectomy or removal of the muscular divider between the top chambers of the heart (called the atrium)

3. Disconnection of the right and left pulmonary artery from the main pulmonary artery

4. Connection of the main pulmonary artery to the hypoplastic aorta to make a “new” aorta.

5. Augmentation or enlarging of the hypoplastic aortic arch

Recovery: Norwood

After surgery, the baby will be in the cardiac intensive care unit (CICU). The baby will be monitored closely in the CICU. The baby will be on a breathing machine and will have a chest tube to drain fluid from around the heart and lungs. Also, the baby will have intravenous lines for monitoring and giving medicines. The length of hospital stay after the Norwood varies. The average length of stay is between 2-3 weeks. After the baby fully recovers from surgery, the baby will be transferred to the regular cardiac floor.

Often after the Norwood, a child will need to learn how to eat. This is because the child may not have been fed by mouth before surgery and may tire more easily than a baby without a heart problem. During this time the baby will be on the regular cardiac floor. Sometimes the child has to go home with a temporary feeding tube. Your child will be on heart medications.

Stage II: Glenn Shunt

For this procedure, the baby is again put on the heart-lung bypass machine. The superior vena cava is attached directly to the pulmonary artery and the BT shunt is removed. This cardiac surgery is less involved than the Norwood procedure because so much of the work was done when the child was a newborn. This procedure is usually done around 6 months of age.

Recovery: Stage II

The length of hospital stay will vary, but the average length of stay is about a week. After surgery, the baby will go to the Cardiac Intensive Care Unit (CICU). As long as the baby is on the breathing machine or needs to be watched closely the baby will stay in the CICU. After the baby fully recovers from surgery, the baby will be transferred to the regular cardiac floor.

Stage III: Fontan Procedure

The final surgery usually takes place around 2 years of age. This stage requires open heart surgery in the Operating Room. The child is on the heart-lung machine the same as Stage II. At this time the blood from the lower part of the body that goes back to the heart through the inferior vena cava is routed to the pulmonary artery directly. This makes all of the blood returning from the body a more “passive blood flow”. After the final surgery is completed, the blood flow from the upper body will return to the lungs by the superior vena cava connection. Blood will reach the lungs from the lower body by the inferior vena cava connection.

Recovery: Stage III

Recovery after surgery will be similar to the Stage II procedure. One important difference is that the child may have more than one chest tube to drain fluid from around the lung. Now all of the blood from the body is returning to the lungs through a “passive route” that requires a higher pressure. Therefore, fluid can leak out around the lungs and needs to be drained. Sometimes these chest tubes need to stay in for a longer time to drain this fluid. The child can be recovering on the regular cardiac floor and is encouraged to be out of bed and playing at this time. Length of stay varies from one to three weeks.

Treatment Option 3: Heart transplant

Heart transplant involves replacing a sick heart with a new heart (donor heart). There are risks involved with heart transplantation. Children will need to be on lifelong medications to prevent their own body from attacking the heart which is called rejection. Long-term complications of transplant include potential rejection, infection, coronary disease, and a special type of lymphoma associated with immunosuppression. Children who require the transplant will be placed on a waiting list administered by a national agency called United Network for Organ Sharing. The wait time can be days, months or even more than a year. Some babies may pass away while on the waiting list. A transplanted heart will last an average of 8-14 years. Some children also require repeat transplantation.

Treatment Option 4: Compassionate care

Sometimes families choose for no surgeries at birth and allow their baby to pass naturally. This is a personal family decision and Nationwide Children's will respect and support you through this decision.

Life After Treatment

It is extremely important to follow up with your regular pediatrician and pediatric cardiologist as instructed.

At any time during this process if you have any questions or concerns regarding your baby please ask the staff at The Heart Center at Nationwide Children's.