Risk of prolonged ischemic time linked to use of cardiopulmonary bypass during implantation for lung transplantation in the United Kingdom

Background: Some degree of ischemia is inevitable in organ transplantation, and for most, if not all organs, there is a relationship between ischemic time and transplant outcome. The contribution of ischemic time to lung injury is unclear, with conflicting recent data. In this study, we investigate the impact of ischemia time on survival after lung transplantation in a large national cohort.

Methods: We studied the outcomes for 1,565 UK adult lung transplants over a 12-year period, for whom donor, transplant, and recipient data were available from the UK Transplant Registry. We examined the effect of ischemia time (defined as donor cross-clamp to recipient reperfusion) and whether standard cardiopulmonary bypass was used using Cox proportional hazards models, adjusting for other risk factors.

Results: The total ischemic time increased from a median under 5 hours in 2003 to over 6.2 hours in 2013. Our findings show that, when the cardiopulmonary bypass was used, there was an increase in the hazard of death (of 13% [95% CI: 5%-21%] for 1-year patient survival) for each hour of total ischemic time. However, if the cardiopulmonary bypass was not used for implantation, this link disappeared-there was no statistically significant change in mortality with increasing ischemic time.

Conclusions: We document that avoidance of bypass may remove ischemic time, within the limits of our observed range of ischemic times, as a risk factor for poor outcomes. Our data add to the evidence that bypass may be harmful to the donor lung.