Hypoplastic Left Heart Syndrome (HLHS) | Treatments

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Fetal cardiac intervention

A small number of prenatally diagnosed fetuses with hypoplastic left heart syndrome (HLHS) may benefit from fetal intervention. Pediatric interventional cardiologists can use a needle or tiny balloon catheter to treat HLHS, as well as certain other fetal cardiac abnormalities. Balloon catheters can be inflated to open abnormal heart valves or other obstructions.

Post-birth treatments for HLHS

If fetal intervention is not an option for your baby, initial treatments before surgery may include:

  • medication to keep the patent ductus arteriosus open 
  • intravenous fluids through a tube inserted into a vein. a feeding tube if your baby has difficulty feeding
  • breathing assistance provided by a mechanical device ensures adequate oxygen delivery
  • balloon atrial septostomy procedure to create an opening in the wall between the upper chambers of the heart to improve mixing of oxygen-rich blood and oxygen-poor blood

HLHS newborn Vinny

HLHS surgery

To treat HLHS, your child will likely need three palliative procedures called the Fontan Sequence. The goal of these surgeries is to enable the fully-functioning right ventricle to do the work normally done by two ventricles and to separate the blue (low-oxygen-content) blood from the red (well-oxygenated) blood.

Norwood Procedure

Developed at Boston Children's, the Norwood Procedure is usually performed in the first week of the baby's life. This procedure connects the right ventricle to the aorta so that its flow will be delivered to the body through branches of the aorta. 

This procedure usually involves rebuilding a small aorta and connecting it to the ventricle. Blood flow to the lungs is provided through a tube, which extends from a branch of the aorta to the pulmonary artery. 

Two alternative procedures — the Sano modification and the hybrid procedure — are sometimes performed, based on surgical preference, the size of the child and the anatomy of the defects. The Sano modification places a conduit between the pulmonary artery and the right ventricle. 

The hybrid procedure establishes a stable outflow by implanting a stent in the ductus arteriosus, connecting the pulmonary artery to the aorta, banding the branch pulmonary artery to restrict some of the pulmonary blood flow. The hybrid procedure typically takes between 60 and 90 minutes, rather than the six-hour, more invasive Norwood. It allows for delaying the major reconstruction until the next stage, when the baby will be stronger and will have built up some immune defenses.

Bi-directional Glenn Shunt

This procedure is usually performed between three and eight months of age. The baby's lungs have matured enough so that blood flows through more easily, and ventricular force is no longer necessary. The bi-directional Glenn shunt is a direct connection between the superior vena cava and the pulmonary artery, diverting half of the blue blood directly to the lungs without the help of the ventricle.

Fontan procedure

With further lung maturity in the baby's first few years, the vessels of the lungs can now accommodate all the body's blue blood, allowing the Fontan procedure to be performed. This procedure connects the inferior vena cava to the pulmonary artery by creating a channel through the heart or a tube alongside the heart to direct its flow to the pulmonary artery. Now, all the blue blood flows passively to the lungs, and the single ventricle pumps exclusively red blood to the body.

Long-term outlook

Children with HLHS will need follow-up care throughout their lives to ensure that their hearts continue to function adequately. Most children will also need heart medication(s). Complications going forward can include arrhythmias (abnormal heart rhythms), heart failure, blood clots and a few other rare problems. 

A cardiologist will help you create a long-term care program as your baby grows into childhood and teen years and will have an ongoing relationship with your family and child.

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