PHILADELPHIA – When a very low birth weight (VLWBW) infant has congenital heart disease needing surgical repair, the two opposing strategies of immediate surgery or delaying surgery for several weeks until the newborn grows larger work equally well for survival. Survival rates after both approaches tracked nearly identically during 3 years of follow-up, in a single center review of 80 cases.

Because the review included a relatively small number of VLBW newborns, the analysis could not determine which benefited most from immediate surgery and which did better with a delayed operation. "But we were reassured that delay did not lead to excess risk," Dr. Edward J. Hickey said at the annual meeting of the American Association for Thoracic Surgery.

Results from a second, related analysis that he reported showed that birth weight surpassed gestational age as a predictor of survival in newborns with congenital heart disease. "Birth weight is a more reliable, independent risk factor for death," said Dr. Hickey, a cardiothoracic surgeon at the Hospital for Sick Children in Toronto. The analysis showed that the highest risk for survival occurred in newborns who weighed less than 2.0 kg at birth. As a result of this finding, Dr. Hickey’s comparison of immediate and delayed surgical repair focused on the 80 newborns in the series who weighed less than 2.0 kg and required prompt intervention.

Among these 80 infants, 34 had "immediate surgery," which meant they had their operation as soon as it could be scheduled and performed, generally within 3 weeks of birth. Surgery for the other 46 was an average of 8 weeks after birth. These differences reflected the way surgeons at Sick Children managed each case.

Among the delayed surgery cases, infants with truncus or coarctation had the slowest growth, with as little as 50 g gained per week. In contrast, infants with an atrial septal defect, tetralogy, or a total anomalous pulmonary venous connection had growth rates above average, often at a pace of more than 150 g/week.

"I was most struck by the infants with coarctation, who seemed to grow at very low rates. That suggests to us that these patients are the ones we should repair early," because it is less likely that a delay would lead to much weight gain and improved surgical prospects, Dr. Hickey said. Based on these findings, he and his associates now perform coarctation repairs in infants whose weight is as low as 1.4 kg, he said. But Dr. Hickey also stressed that the timing of surgical repair must be individualized for each patient.

The two analyses done by Dr. Hickey and his associates involved 1,557 children with congenital heart disease admitted to the Hospital for Sick Children at age 30 days or younger who underwent active management during a 10-year period. Overall survival in this group was 91% at 3 months after admission, 88% after 6 months, and 86% after 5 years.

They evaluated the impact of both gestational age and birth weight on survival among these children, and found that both parameters were linked to mortality. Infants born at 28 weeks’ gestational age had a roughly 40% survival rate after 1 year, those born at 32 weeks had about a 60% survival rate to 1 year, and those born at 36 weeks had about an 80% survival rate at 1 year.

When analyzed by birth weight, those born at 3.5 kg or larger had a greater than 90% 1-year survival rate, those born with a weight of 2.0 kg had about an 80% 1-year survival, and those born weighing 1.5 kg had about a 60% survival to 1 year. These data identified an inflection point where infants born weighing less than 2.0 kg had a substantially worse survival than those who weighed 2.0 kg or more. Additional analysis that compared the relative contributions of gestational age and birth weight also showed that birth weight was the much stronger factor influencing 1-year survival.

The series included 149 infants born at less than 2.0 kg, highlighting how uncommon it is for surgeons to face the question of how to manage VLBW infants with congenital heart disease. Eighty-five of these infants (57%) weighed 1.5-1.9 kg at birth, while the remainder weighed less than 1.5 kg. Thirty did not require immediate surgical intervention, 12 had other, noncardiovascular complications requiring initial intervention, and 27 received comfort care only, leaving 80 candidates that became part of the immediate – versus delayed – surgery analysis.

Among the 46 infants whose surgery was delayed for an average of 8 weeks, 18 (39%) had a total of 33 complications. Six of these 18 children died while awaiting surgery. "Despite this high complication rate, we see roughly equivalent survival" between the immediate and delayed surgery groups. That observation, coupled with the finding that many infants gained weight at an "acceptable" rate during the period of surgical delay, led to the conclusion that either strategy is reasonable and should depend on the specific features of each case, he said.

Dr. Hickey had no disclosures. ☐

Similar Survival in VLBW Infants with Delayed Surgery