For babies with heart defects, death risk is far lower at most experienced hospitals

Each year, thousands of babies are born with severe heart defects that must be operated on within days or weeks of their birth. And though the odds for these infants are much better now than they were even 10 years ago, a new study suggests that there may be a way to give them an even better chance at living: Get them to the hospitals that are the most experienced at handling such cases.

In the first national study of this issue, a team of University of Michigan researchers found that infants with specific complex heart defects are much less likely to die before leaving the hospital if they are treated at the centers that treat the largest numbers of these patients. This relationship between hospital volume and mortality has been seen in adult heart operations, but the new study suggests it holds true for infants as well. The study is published online in the journal Pediatric Cardiology.

“A generation ago, we were just happy when these patients lived, but that’s not good enough anymore,” says lead author Jennifer Hirsch, M.D., a U-M pediatric cardiac surgeon and member of the Michigan Congenital Heart Center. “Although mortality rates are much lower, there is still a significant variation between centers. This study indicates that it may be time to selectively regionalize these patients’ care, to give them the best chance at a good outcome.”

Hirsch and her colleagues based their study on data from the 2003 Kids’ Inpatient Database, a national database sponsored by the Agency for Healthcare Research and Quality that includes information on children hospitalized in 36 states.

They analyzed data for two of the most severe congenital heart defects: transposition of the great arteries (TGA), in which the major blood vessels leading between the heart and lungs are switched, and hypoplastic left heart syndrome (HLHS), in which the left side of the heart does not develop properly.

Both defects are lethal if not treated within a few weeks of birth, with operations called the arterial switch operation for TGA and the Norwood procedure for HLHS. Infants may need additional operations later in life, but these initial open-heart procedures are critical for their survival.

The study shows that an infant’s risk of dying in the hospital during or after their operation varied greatly depending on the number of each procedure performed that year at the hospital where they were treated. Mortality rates ranged from more than 10 percent to less than 1 percent for the arterial switch operation, and from more than 35 percent to around 10 percent for the Norwood procedure.

“The relationship between hospital volume and risk of dying was significant across the spectrum for both defects, though in the case of arterial switch operations the difference dwindled among hospitals that performed about 15 or more in a year,” says Hirsch, a Lecturer in the Section of Cardiac Surgery at the U-M Medical School who performs operations at the U-M C.S. Mott Children’s Hospital. “For the Norwood, the trend to decreased mortality did not level off.”