Hypoplastic Left Heart Syndrome (HLHS) | Treatments

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Contact the Complex Biventricular Repair Program

Boston Children's Hospital is known for successfully pioneering cardiac treatments. A large part of our success comes from our commitment to research—and to advancing the frontiers of what's possible in cardiac medicine through the world's largest research program at a pediatric institution.

Shaping new advances in fetal and newborn care, our researchers work just steps away from our physicians and patients—giving doctors a vital jump-start on applying lifesaving research discoveries to real-life patient care.

Fetal (prenatal) cardiac intervention

Our physicians have pioneered refinements to this complex intervention, and we're the world's largest and most experienced center performing fetal cardiac interventions. Patient families come from around the world for treatment with this new approach.

Fetal cardiac intervention is appropriate in certain select situations. If your child is a candidate, the procedure will be coordinated by your team at the Advanced Fetal Care Center (AFCC). Children's 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.

After the baby is born, if he develops HLHS, he will have a series of three surgical interventions between a few months and a few years of age. Learn more about the Fontan Sequence.

Immediate post-birth treatments

If fetal intervention is not an option for your baby, the AFCC will plan and coordinate his postnatal care to ensure the best possible outcome for him and the family. As soon as your baby is born, Children's will begin treating him, so that we may ultimately put your child on the path to good health.

How we treat your child depends on the extent of the disease and other variables, but initial treatments in the cardiac ICU typically include:

  • IV (intravenous) medication to keep the PDA open
  • intravenous fluids
  • for a few babies, breathing provided by a mechanical device
  • balloon atrial septostomy (usually not necessary if an atrial septal defect [ASD] is present): creates an opening in the atrial septum (wall) between the upper chambers of the heart (the left and right atria) to improve the mixing of oxygen-rich (red) blood and oxygen-poor (blue) blood
  • A few unusually ill patients will require support using a heart/lung bypass machine that circulates oxygenated blood through the baby's body

Three staged surgeries: the Fontan Sequence

In treating HLHS, cardiac surgeons perform three palliative procedures called the Fontan Sequence. The goals of these surgeries are to:

  • enable the fully-functioning right ventricle to do the work normally done by two ventricles
  • separate the blue (low-oxygen-content) blood (pulmonary circulation) from the red (well-oxygenated) blood (systemic circulation)
  • Stage I: the Norwood Procedure: Developed at 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, called the modified Blalock-Taussig Shunt, which extends from a branch of the aorta to the pulmonary artery.

    Two alternative procedures to the Norwood Procedure are sometimes performed, based on surgical preference, the size of the child and the anatomy of the defects. These are:

the Sano modification: places a conduit between the pulmonary artery and the right  ventricle instead of the modified Blalock-Taussig Shunt

the hybrid procedure: combines cath lab techniques, such as stenting, with surgical techniques. In this procedure, the interventional cardiologist and the cardiovascular surgeon work together.

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 Stage II, when the baby will be stronger and will have built up some immune defenses.

The other advantage of this procedure is that it does not require the baby to be on the heart-lung machine during the surgery, which may reduce the risk of certain complications.

  • Stage II: bi-directional Glenn Shunt: 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.
  • Stage III: Fontan procedure (operation): 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 done.

    The procedure connects the inferior vena cava to the pulmonary artery by creating a channel (“baffle”) 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.

A word about heart transplants: A very few institutions perform heart transplants as a primary therapy, rather than the staged Fontan procedures. At Boston Children's, we perform transplants only if patients don't respond to other surgery. Such an occurrence at Boston Children's is very unusual.

Coordinated post-procedure care from Boston Children's AFCC

Before, during and after each stage of your child's treatment and recovery, the AFCC's caring staff will help you to coordinate care services, appointments, counseling, social services and travel and lodging arrangements.

At home: caring for your child after HLHS treatment

Your child's cardiologist will follow your baby's progress closely, and will offer recommendations for post-operative follow-up care—including a nutritional program to encourage weight gain, an oral hygiene program to prevent infection, and an appropriate exercise routine.

We'll also help you to create a longer-term care program as your baby matures into childhood and his teen years. Families who have a child with HLHS will have an ongoing relationship with their cardiologist. We will consult and treat if complications arise, and we'll advise on daily-life issues such as exercise, activity levels, nutrition and pregnancy precautions.

As your baby recovers and grows, be sure to follow a regular program of well-baby/well-child checkups. And to the greatest extent possible, encourage your child to live normally. Even if some physical activities are limited, your child and your family can enjoy a full life together.

Boston Children's Home Monitoring Program for your child

An infant with single ventricle anatomy needs support with shunt-dependent blood flow between his Stage I and Stage II surgical repairs (see surgery descriptions above on this page).

The results of the Stage I surgery have improved—with nearly 90% of infants who are cared for in experienced centers discharged home after the first stage. So we can now focus new attention on reducing the known mortality of 10 to 15 percent for these infants between their Stage I and Stage II surgical repairs.

Research shows the vital importance of a Home Monitoring Program, including daily at-home assessments of oxygen saturations and weight between the Stage I and Stage II surgeries.

Checking your baby's daily weight:

  • alerts you and your child's providers to dehydration
  • enables appropriate immediate intervention
  • decreases the risk of sudden death at this very fragile stage in your infant's multiple-surgery sequence

During this period between the Stage I and Stage II surgeries, your child's pediatric cardiologist and pediatrician will be in close contact with you as your child's primary home caregiver. (After your child's Stage II repair, this intensive level of home monitoring will no longer be necessary.)

In Boston Children's Home Monitoring Program:

  • You'll be given detailed guidelines and goals for your child's:
    • growth
    • weight gain
    • oxygen saturations
  • You'll be instructed to call your child's cardiologist if his goals for growth, weight gain and oxygen saturation aren't met, or if:
    • your child is breathing harder, faster or is fussy beyond his baseline
    • you have any questions or concerns
  • You'll be supplied with a pulse oximeter and a baby scale and shown how to use both instruments. You'll measure your child's saturations twice a day and weigh the baby daily—checking against given guidelines and goals.
  • You'll record your baby's weights, oxygen saturations and general observations in a daily log, and will share this log with the pediatrician/cardiologist during check ups.
  • You'll consult your pediatrician if your child:
    • is experiencing nausea/vomiting/diarrhea
    • is not having sufficient wet diapers
    • is feverish
  • You'll have weekly calls with your designated pediatric nurse practitioner, who will consult with you, and who will notify your child's cardiologist of any concerns that arise.

As he grows: your child's long-term outlook

Babies with HLHS will need three surgeries in their first few years of life; and children will need follow-up care throughout their lives to ensure that their hearts continue to function adequately. They are never entirely cured of their cardiac defect, and will probably need to take heart medications.

The most positive outcome is that a child can undergo these surgeries and not have any symptoms going forward. On the other hand, there are children whose hearts struggle with their single ventricle.

Boston Children's cardiologists will follow your child's recovery and progress, and will provide further treatment, if needed. There is a risk of complications, including arrhythmias, heart failure and blood clots. And the potential does exist for needing a heart transplant in early or mid-adulthood.

Thanks to sophisticated diagnoses and treatment innovations, babies with HLHS who would not have survived a mere 20 years ago now have a good chance for a full life. And the medical science on HLHS and other congenital heart defects continues to evolve and improve.

Coping and support

Before, during and after each stage of your child's treatment and recovery, our Advanced Fetal Care Center (AFCC) staff will help you coordinate care services, appointments, counseling, social services and travel and lodging arrangements.

AFCC caregivers will acquaint you with the Boston Children's Center for Families, where you can find family-to-family support groups and an array of services.

Also, our Boston Adult Congenital Heart and Pulmonary Hypertension Service (BACH) is an international center for excellence, providing long-term inpatient and outpatient care and advanced therapies for people with congenital heart disease as they progress to adulthood.

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- Sandra L. Fenwick, President and CEO

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