Influence of graft ischemic time and geographic distance between donor and recipient on survival in children after lung transplantation

Background The optimal ischemic time in pediatric lung transplantation (LTx) is unclear, as recent studies have challenged the relevance of 6 hours as an upper limit to acceptable ischemic time. Methods Pediatric LTx recipients transplanted between 1987 and 2013 were identified in the United Network for Organ Sharing (UNOS) registry to compare survival according to ischemic time, which was categorized as <4 hours, 4 to 6 hours and >6 hours. Results Nine hundred thirty patients, all <18 years of age and receiving a first-time LTx from a cadaveric donor, were included in our investigation. Compared with <4 hours of ischemic time, univariate analysis showed a significant reduction in mortality hazard with 4 to 6 hours (hazard ratio [HR] = 0.640; 95% confidence interval [CI] 0.502 to 0.816; p < 0.001) but not >6 hours (HR = 0.985; 95% CI 0.755 to 1.284; p = 0.909). A multivariate Cox model confirmed the lowest mortality hazard to be 4 to 6 hours, as compared with <4 hours (HR = 0.533; 95% CI 0.376 to 0.755; p < 0.001). A prolonged ischemic time of >6 hours was associated with increased mortality hazard relative to the 4 to 6 hours (HR = 1.613; 95% CI 1.193 to 2.181; p = 0.002). Supplementary analyses examining geographic distance between donor and recipient identified no association between geographic distance and recipient mortality hazard. Conclusions An ischemic time of 4 to 6 hours was associated with optimal long-term survival in first-time pediatric LTx recipients, whereas a very short ischemic time of <4 hours and a prolonged ischemic time >6 hours were both associated with higher mortality hazard in this population.