Association of graft ischemic time with survival after heart transplant among children in the United States.

BACKGROUND: Previous studies have found no association between graft ischemic time (IT) and survival in pediatric heart transplant (HTx) recipients. However, previous studies were small or analyzed risk only at the extremes of IT, where observations are few. We sought to determine whether graft IT is independently associated with graft survival in a large cohort of children with no a priori assumptions about where the risk threshold may lie.

METHODS: All children aged <18 years in the U.S. undergoing primary HTx (1987 to 2008) were included. The primary end point was graft loss (death or retransplant) within 6 months. Multivariate analysis was performed to analyze the association between graft IT and graft loss within 6 months after transplant. A secondary end point of longer-term graft loss was assessed among recipients who survived the first 6 months after transplant.

RESULTS: Of 4,716 pediatric HTxs performed, the median IT was 3.5 hours (interquartile range, 2.7-4.3 hours). Adjusted analysis showed that children with an IT > 3.5 hours were at increased risk of graft loss within 6 months after transplant (hazard ratio, 1.3; 95% confidence interval, 1.1-1.5; p = 0.002). Among 6-month survivors, IT was not associated with longer-term graft loss.

CONCLUSIONS: IT beyond 3.5 hours is associated with a 30% increase in risk of graft loss within 6 months in pediatric HT recipients. Although the magnitude of risk associated with IT is small compared with the risk associated with recipient factors, these findings may be important during donor assessment for high-risk transplant candidates.