How do Babies With Single Ventricles Fare Between Stage 1 and 2 Hybrid Palliation?

January 3, 2019

The world’s busiest hybrid palliation team is working to improve outcomes by analyzing what happens between surgeries, including readmissions and other serious events.

Most infants with hypoplastic left heart syndrome or other congenital heart defects resulting in a single ventricle undergo the Norwood operation. This traditional approach frontloads the greatest mortality risk to the initial operation, and subsequent surgeries pose minimal risk to patients. An alternative approach, called hybrid stage 1 palliation, offers a less-invasive, lower risk initial surgery and puts off the more complex operation until patients are 4 to 6 months old — and, ideally, physiologically more robust and resilient. The hybrid approach reduces the cumulative risk of serious complications and death.

Having already demonstrated the comparative safety and overall surgical outcomes of babies undergoing hybrid palliation, the team conducting more of these procedures than any other heart center in the world has released an examination of events taking place in between the procedure’s first two stages.

“It seems that the maintenance of hybrid patients between the two procedures is more intense. They have more frequent returns to the hospital and greater need for additional catheterizations,” says Mark Galantowicz, MD, chief of Cardiothoracic Surgery in The Heart Center at Nationwide Children’s Hospital and senior author on a recent publication of the center’s interstage outcomes data. “But that doesn’t equal higher risk or worse outcomes — it just means there’s more to be done to manage these babies appropriately.”

The study, published in Congenital Heart Disease, found that of 57 infants discharged home after hybrid stage 1 palliation, 75 percent had at least one interstage readmission to the hospital. Of those patients, 14 had major adverse events, including stroke, sepsis, and unexpected cardiac catheterization requiring intervention. Four patients (7 percent) died during the interstage period.

Compared to data published from other centers with patients primarily undergoing the Norwood procedure, hybrid stage 1 palliation patients appear to have similar or higher readmission rates and similar or higher interstage intervention rates, although small patient populations made statistically significant comparisons difficult.

The Heart Center’s study also explored the causes and circumstances surrounding serious adverse events and patient death, as well as the possible impact of the implementation of a comprehensive single ventricle team with standardized protocols for home monitoring. The Heart Center created such a team in 2014 — midway through the study period of 2012 to 2016. It includes dedicated single ventricle cardiologists and meets quarterly to discuss ongoing quality improvement, protocol feedback and data for both inpatients and those at home between stages of the hybrid operation.

“We meet as a single ventricle team, focused on and charged with continuing to improve the outcomes for these complex babies,” says Dr. Galantowicz, who is also co-director of The Heart Center at Nationwide Children’s. “We’re continually evaluating our home monitoring process, which engages both the family and nurse practitioners via an early warning system. The system is built to identify early any child not doing perfectly, thereby allowing early evaluation and intervention to prevent serious adverse outcomes.”

The team is continuing to gather additional data on interstage outcomes between stages 1 and 2 of the operation and has now also begun evaluating outcomes between palliation stages 2 and 3. The Heart Center participates in a national quality collaborative aimed at improving interstage management of complex single ventricle patients and is the key contributor for data surrounding the hybrid palliation approach.

Dr. Galantowicz is optimistic that, in time, identification of effective management strategies for interstage hybrid palliation patients will reduce the procedure’s overall risk even further. “Whether centers take a traditional or hybrid pathway, the interstage period is important for the health of these babies, and learning from each other about how to optimize that phase of care is important.”


Simsic JM, Phelps C, Kirchner K, Carpenito KR, Allen R, Miller-Tate H, Texter K, Galantowicz M. Interstage outcomes in single ventricle patients undergoing hybrid stage 1 palliation.Congenital Heart Disease. 2018 Jul 18. [E-pub ahead of print]

Image credit: Nationwide Children’s