Surgical Timing in Infants with Tetralogy of Fallot

Surgical Timing in Infants with Tetralogy of Fallot
Research connects a 12-month growth advantage to primary repair.

Early interventions for neonates with tetralogy of Fallot vary across children’s hospitals. Some congenital heart disease specialists lean toward full repair as early as the infant’s size and stability allow. Others lean toward a staged approach with palliative interventions followed by primary repair.

George Nicholson, M.D., a pediatric cardiologist at Monroe Carell Jr. Children’s Hospital at Vanderbilt, has been examining the impact of management strategy on growth in neonates with cyanotic tetralogy of Fallot. In results that he and colleagues had planned to present at the 2020 Pediatric Academic Societies conference, they found mild or no discrepancies in babies’ somatic growth during the first 4 to 8 months of life, but by 12 months the growth advantage favored babies who had early primary repair.

“There is a large population where the decision criteria are murky.”

“There is a large population where the decision criteria are murky. We wanted to add valuable data to the criteria used in making these decisions,” Nicholson said.

Primary vs. Staged Repair

Primary surgical repair for tetralogy of Fallot entails closing the large ventricular septal defect and alleviating the obstruction to pulmonary blood flow, therefore creating a two-ventricle septated heart. “This establishes virtually normal cardiopulmonary physiology,” Nicholson said.

Palliative interventions include aortopulmonary shunts, right ventricular outflow tract or patent ductus arteriosus stent placement, or performing a balloon pulmonary valvuloplasty to provide sufficient pulmonary blood flow. If the palliative route is chosen, the patient will need to undergo complete surgical repair later on.

Physicians must assess the risks inherent in the procedures and hospitalizations involved in early primary repair versus the risks of staged repair. One key factor in the decision matrix is the effect on neurodevelopment. Since a baby’s growth correlates strongly with neurodevelopment, Nicholson’s team analyzed feeding and growth patterns in both groups.

Growth Fluctuations

The retrospective study looked at 394 babies under 30 days old from nine children’s hospitals. Among them, 138 babies had primary and 256 had staged repair procedures. The primary outcome was changed in weight-for-age from initial intervention to 4 to 8 months old. “This is considered a useful period for comparison since most patients with this condition will undergo complete surgical repair by this age, whether they are cyanotic or not,” Nicholson said.

Infants who underwent primary repair had a greater decline in weight at the time of initial hospitalization. However, by 12 months old, they demonstrated improved weight gain compared to those who underwent a staged repair.

“It wasn’t surprising to me because primary repair puts them in two-ventricle physiology much earlier in life than initial palliative measures do,” Nicholson said. Babies with staged repair have growth setbacks with each intervention, culminating in their definitive repair between 4 and 8 months old, he said.

“When you compare the cumulative burden of the staged repair approach to the primary repair strategy over the first year of life, these outcomes began to favor the primary repair group.”

“When we looked at neonatal exposures in terms of complications, ICU length of stay, duration of ICU exposures and procedural/surgical times, they were all lower in the staged repair group. However when you compare the cumulative burden of the staged repair approach to the primary repair strategy over the first year of life, these outcomes began to favor the primary repair group.”

Weighing Growth and Mortality Risks

Nicholson acknowledges that if you are starting with a child who is quite ill and tenuous, the prospect of performing primary repair is often met with trepidation. “In that case, you go with the safer initial procedure early on, knowing fully well that in the end, there might be more cumulative exposures, and a potentially adverse impact on growth,” he said.

The study data support this concern, demonstrating a higher early mortality risk in the primary repair group. However, the gap begins to close after that. “The data tells us that at 12 months the overall risk of death is equivalent,” Nicholson said.

Nicholson and colleagues have also evaluated the impact of different palliation strategies on infant feeding and somatic growth as part of the Congenital Catheterization Research Collaborative.