June 22, 2001 Philadelphia, Pa. — Fetal echocardiography is increasingly used to detect congenital heart defects before birth, although whether prenatal diagnosis benefits children with heart disease has been questioned. A new study by The Children’s Hospital of Philadelphia suggests that newborns with a severe, life-threatening defect called hypoplastic left heart syndrome (HLHS) are less likely to have early neurologic problems, such as seizures or comas, if HLHS is diagnosed before birth.
The researchers found that prenatal detection of the heart defect allowed better treatment, such as delivering the baby in an advanced, high-risk nursery, and promptly providing the drug prostaglandin to maintain blood flow until the first stage of reconstructive surgery can be performed. Compared to newborns with HLHS diagnosed after birth, infants diagnosed prenatally were half as likely to experience seizure or coma prior to or within 6 weeks of their surgery. The research was reported in the June 2001 issue of the journal Pediatrics.
Children with HLHS are born with a severely underdeveloped left ventricle, but may appear healthy at birth. When a blood vessel in a newborn’s heart called the ductus arteriosus closes within a few days of birth – a normal event – a baby with HLHS has severe circulation problems because of the heart defect. "If diagnosis of HLHS is delayed, severe organ damage may occur, especially to the brain," says William T. Mahle, M.D., an attending cardiologist at The Children’s Hospital of Philadelphia, and lead author of the current study. "Our study was the first to examine an association between prenatal diagnosis and early neurological events. We will continue to follow these children to see if there is any effect on their cognitive function as they develop."
The researchers studied 216 newborns with HLHS referred to Children’s Hospital for heart surgery between 1992 and 1997, 79 of whom were diagnosed prenatally. The study was part of a larger project studying the neurological benefits of a drug used in infants with heart disease. The researchers found survival rates after the first stage of surgery to be the same, 74 percent, regardless of whether HLHS was diagnosed before or after birth, a result consistent with previous studies at other centers.
Since the period of that study, added Dr. Mahle, survival rates have continued to improve. At Children’s Hospital, 86 percent of infants with HLHS survived the first stage of surgery from January 1999 to April 2000. Before the advent of this surgery in the early 1980s, HLHS was invariably fatal. Surgery for the condition is now performed in three stages during the first one to two years of life.
"As survival rates for HLHS and other congenital heart disease have soared over the past 20 years, physicians have been better able to concentrate on longer-term quality of life for these children," said Dr. Mahle. "Recent data from the Cardiac Center at Children’s Hospital and other pediatric centers suggest that long-term neurological outcomes such as I.Q. may be improving in children who underwent complex heart surgery as infants, including children with HLHS."
However, children with HLHS remain at a higher risk of long-term cognitive and neurological problems, compared to children with other heart defects. "Those long-term neurological problems may result both from early complications of the disease, and from the need for circulatory arrest during the surgery," says Dr. Mahle. "We hope to show that prenatal diagnosis, in addition to reducing short-term neurological problems, also improves long-term functioning. We will follow the children in the study as they attain school age to assess how well they’re doing cognitively and neurologically."
Co-authors of the study with Dr. Mahle are Robert R. Clancy, M.D., and Susan P. McGaurn, of the Division of Neurology; and Bernard J. Clark, M.D., of the Division of Cardiology, all of Children’s Hospital; and James E. Goin, Ph.D., of the DataMedix Corporation, of Media, Pa. The study was supported in part by the National Institutes of Health.
Founded in 1855 as the nation's first pediatric hospital, The Children’s Hospital of Philadelphia is ranked today as the best pediatric hospital in the nation by a comprehensive Child Magazine survey. Its pediatric research program is among the largest in the country, ranking second in National Institutes of Health funding.
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