New Evidence Offers Ways to Improve Neonatal HLHS Survival

Infants with hypoplastic left heart syndrome (HLHS) born far from a hospital that provides neonatal cardiac surgery for HLHS have increased neonatal mortality, with most deaths occurring before surgery, according to findings from a recent multicenter study conducted by experts from Baylor College of Medicine (BCM), the Texas Department of State Health Services, University of Texas Southwestern Medical Center in Dallas, and the University of South Florida.

Researchers also concluded that efforts to improve prenatal diagnosis of HLHS and subsequent delivery near a large-volume cardiac surgical center may significantly improve neonatal HLHS survival.

“Our study is the first to examine the interactions between prenatal diagnosis, birth location and cardiac surgical center volume to determine survival among infants with HLHS,” said Dr. Shaine Morris, lead researcher, pediatric cardiologist at Texas Children's Hospital and assistant professor of pediatrics-cardiology at BCM. “These findings are essential to providing the most successful outcomes for our patients.”

HLHS occurs when the fetus’s left side of the heart does not develop normally. The condition affects approximately 1 in 6000 live births. HLHS is one of the most complex heart defects to treat because most of the structures on the left side of the heart are too small and underdeveloped, or hypoplastic, and it is difficult for the heart to provide enough red blood flow for the body’s needs.

The mortality rate associated with HLHS is quite high, and optimal outcomes depend on aggressive cardiology and surgical management. All children with HLHS will require at least 3 surgeries within the first 3 years of life to survive, the study authors explain. However, many infants with HLHS die in the first few months of life.

The research was based on Texas Department of State Health Services' Texas Birth Defects Registry data from 1999-2007 that was used to retrospectively examine associations between distance from birth center to a cardiac surgical center (driving time), number of newborns cared for with HLHS at each hospital, and neonatal mortality in infants with HLHS.

Of the more than 3.4 million births during the study period, 463 infants with HLHS were assessed. Mothers delivering farther from a cardiac surgical center were less educated and more often lived in a poverty-stricken area. In addition, 39% of newborns studied were diagnosed prenatally with HLHS and delivered significantly closer to a cardiac surgical center.

Of the newborns with HLHS who died, 40% were born more than 90 minutes from a cardiac surgical center, compared with 21% born within 10 minutes of a surgical center. The percentage of patients who died after the first surgery for HLHS was 2 to 4 times higher in low-volume surgical centers than in the highest-volume centers.

Overall, in the latest years of the study, newborns with a prenatal diagnosis, born less than 10 minutes from a cardiac surgical center, and cared for at a large-volume cardiac surgical center had a neonatal mortality rate of 6%. In comparison, for those born in the same era without a prenatal diagnosis, born more than 10 miles from a cardiac surgical center, and cared for at a low-volume cardiac surgical center, the 28-day mortality rate was 29%.

Pertinent Points:
- Infants with hypoplastic left heart syndrome (HLHS) born far from a cardiac surgical center have increased neonatal mortality, and most of this mortality is presurgical.
- Efforts to enhance prenatal diagnosis of HLHS and subsequent delivery near a large-volume cardiac surgical center may significantly improve neonatal HLHS survival.

References:

Reference

Morris SA, Ethen MK, Penny DJ, et al. Prenatal diagnosis, birth location, surgical center, and neonatal mortality in infants with hypoplastic left heart syndrome.

Circulation.

2013 Oct 17. [Epub ahead of print]