Background Previous studies suggest that infant heart transplant (HT) recipients are at higher risk of developing severe
primary graft dysfunction (
PGD) than older children. We sought to identify risk factors for developing severe
PGD in infant HT recipients. Methods and Results We identified all HT recipients aged <1 year in the United States during 1996 to 2015 using the Organ Procurement and Transplant Network database. We linked their data to ELSO (
Extracorporeal Life Support Organization) registry data to identify those with severe
PGD, defined by initiation of
extracorporeal membrane oxygenation support for
PGD within 2 days following HT. We used multivariable logistic regression to assess risk factors for developing severe
PGD. Of 1718 infants analyzed, 600 (35%) were <90 days old and 1079 (63%) had
congenital heart disease. Overall, 134 (7.8%) developed severe
PGD; 95 (71%) were initiated on
extracorporeal membrane oxygenation support on the day of HT, 34 (25%) the next day, and 5 (4%) the following day. In adjusted analysis, recipient
congenital heart disease,
extracorporeal membrane oxygenation, or biventricular assist device support at transplant, recipient blood type AB, donor-recipient weight ratio <0.9, and graft ischemic time ≥4 hours were independently associated with developing severe
PGD whereas left
ventricular assist device support at HT was not. One-year graft survival was 48% in infants with severe
PGD versus 87% without severe
PGD. Conclusions Infant HT recipients with severe
PGD have poor graft survival. Although some recipient-level risk factors are nonmodifiable, avoiding modifiable risk factors may mitigate further risk in infants at high risk of developing severe
PGD.