The first surgeries to correct HLHS were developed in the early 1980s. Since then, these surgeries have been constantly refined and improved, and more and more children are able to survive the rigorous series of open-heart surgeries that are required to establish adequate circulation. Today, parents have new hope that their HLHS baby will be able to live a longer life. Open-heart surgeries are currently available to treat HLHS: heart transplant surgery and the Norwood procedure (followed by a series of three surgeries, each done at a different age, ranging from infancy through the toddler years). Both heart transplant and the Norwood procedure carry risks and are only performed by specialized pediatric heart surgeons.

Before surgery is performed, therapy for HLHS babies begins with an intravenous infusion of a drug called prostaglandin. If the child has been diagnosed before birth, prostaglandin administration will begin immediately after birth. This hormone-like substance will help keep the ductus arteriosus open, thus allowing oxygen-rich blood to reach the tissues of the body. Babies may also be put on a ventilator to assist breathing if necessary.

Heart transplants and HLHS

A heart transplant involves replacing the baby’s defective heart with a donated healthy heart (a relatively new procedure in newborns). The baby’s eligibility for a transplant is determined by the results of blood tests and other specific factors relating to the baby's health and potential for survival. Once that determination is made, he or she is entered into a computerized national waiting list.

There is a shortage of heart donors, especially within the newborn population. Each year, only about 300 transplants are performed worldwide on young people under the age of 18. Therefore, transplantation usually involves a long, uncertain waiting period during which the infant is on “standby” for a suitable heart. Some patients’ hearts give out before a suitable donor heart can be found.

Even if a donor heart match is made, transplantation carries a risk of rejection and the early development of conditions such as coronary artery disease or lymphoma – cancer of the lymph nodes. Lifelong use of medication to prevent rejection and infection must be taken, including the use of antibiotics before dental procedures and certain surgeries to prevent endocarditis. Lifelong medical management will be necessary, and the long–term results for newborn transplantations are not yet known.

Most pediatric cardiology surgical centers do not offer transplant as the initial option. The Norwood procedure and its modifications are by far the most frequently pursued approach for newborns with HLHS.

Norwood procedure for HLHS

The Norwood procedure, which was introduced in 1983, as well as other further surgeries that may include a bi-directional Glenn shunt, hemiFontan, and the Fontan procedure, are a series of three open-heart surgeries. Each open-heart surgery is done at a different age, ranging from infancy through the toddler years. The first two surgeries (Stages I and II) are designed to temporarily relieve blood flow problems to and from the lungs. The third surgery (Stage III) is used to permanently establish blood flow to the lungs by bypassing the heart. The three surgeries are done at three different ages, which are as follows:

Initial results from the surgery have been good. Overall, survival at five years is 70 to 75 percent and HLHS children have reached their teenage years. Research has found a higher incidence of learning disabilities, cerebral palsy and mental retardation among children who have undergone the procedure.

It is possible, however, that these complications are a result of different surgical methods than are in use today. Most of the children in these studies underwent their surgeries in the 1990s or late 1980s, when longer periods of circulatory arrest were common. Today, the operations have been refined and move more quickly, thus limiting the children's time on cardiopulmonary bypass. Follow-up studies will help determine if the deficits seen among earlier children are still present, meaning that they are related to HLHS itself rather than the surgical approach. Some modifications in routine child care, schooling, and activity participation may be necessary.

Researchers, however, are still looking for ways to improve the Norwood procedure. One study showed that a mechanical device called a ventricular assist device (VAD) might help infants survive the series of operations. This device helps the heart pump oxygen-rich blood from the heart to the rest of the body. The VAD for infants is still in research stages and there is very limited evidence about its use in humans in general.

It should be remembered that surgical treatment for this condition does not cure HLHS. It corrects most of the circulation problems but specialized medical care and medications to maintain the heart’s efficiency are required throughout life.