October 1st, 2009 
Infants born with a rare heart defect may have better outcomes when surgery to repair the heart is done while the infant is still in the womb, Harvard University researchers say.
The condition, hypoplastic left heart syndrome, occurs when the fetus’s left ventricle is underdeveloped and the heart cannot pump enough blood to sustain life. It affects about 1 in 10,000 newborns, and without open-heart surgery within a week of birth, these infants face death. Even with the heart repair, the children lead restricted lives and need at least one heart transplant, researchers say.
“Using the new procedure, in about 30 percent of the fetuses [with technically successful operations], there was an outcome of a two-ventricle circulation after birth,” said Dr. Doff B. McElhinney, an assistant professor of pediatrics at Harvard Medical School and an associate in cardiology at Children’s Hospital Boston.
How well the infants in the study will fare over the long term isn’t known, but the researchers intend to follow them as they grow up, McElhinney said.
In fetuses, aortic stenosis usually progresses to hypoplastic left heart syndrome, the study explains. Prenatal intervention could reduce the total number of surgeries required over a lifetime, eliminate the need for a heart transplant and possibly improve the children’s quality of life, he said.
According to the study, 51 of 68 procedures were considered technically successful, and 17 infants (33 percent of the 51) were born with a fully functioning heart.
The operation involves threading a catheter through the mother’s abdomen into the fetus’s heart. A balloon at the end of the catheter enlarges the aortic valve that controls blood flow from the left ventricle into the aorta and then into the body, McElhinney explained.
The window for performing the procedure is narrow — at around 20 to 21 weeks of pregnancy, McElhinney said. With time, experience and better technology, the success rate will get better, he added.
“By no means is this revolutionizing the care for all fetuses with hypoplastic left heart syndrome,” he said. “It’s applicable only in a small subset of those with this disease, and it’s working in a relatively small percentage of those in whom we attempt it,” he said. And even infants who had a successful procedure needed additional procedures after birth, he noted.
Still, while not a “ringing success,” he said it reinforces the belief that prenatal intervention can be used to change the development of serious forms of heart disease.
