(HealthDay)—A considerable proportion of neonates with critical congenital heart disease (CCHD) are not referred to a cardiac center by age 4 days, according to a study published online June 30 in Pediatrics.

David E. Fixler, M.D., from the University of Texas Southwestern Medical Center in Dallas, and colleagues describe the correlation between timing of referral to a cardiac center and mortality in 2,360 neonates with CCHD, born before screening (1996 to 2007). The date of first at a cardiac center was used to ascertain the age at referral.

The researchers found that the median age at referral was 1 day, while 27.5 percent of neonates were referred after age 4 days, and no record of referral was found for 7.5 percent of neonates. For those referred at age 0 to 4 days, 5 to 27 days, and with no referral, was 18.1, 9.0, and 38.8 percent, respectively. Across two eras within 1996 to 2007, no improvement was seen in age at referral.

"A significant proportion of with CCHD experienced late or no referral to cardiac specialty centers, accounting for a significant number of the deaths," the authors write.