Double Trouble: Ischemic Time is Associated with Worse Outcomes After Double Lung but Not Single Lung Transplantation

Abstract

Purpose Currently accepted clinical guidelines recommend ischemic times of no longer than four to six hours. To maximize organ supply, ischemic times beyond this are sometimes necessitated. We sought to determine whether graft ischemic time is independently associated with all-cause survival in a large, contemporary cohort of single and double lung transplant recipients. Methods Data from adults undergoing initial isolated lung transplantation in the UNOS (United Nation for Organ Sharing) registry from January 2010 to December 2017 were included and compared for all-cause mortality at 1 year. Within single lung transplants, patients were further stratified into 3 ischemic time groups: <3 hours (17%), 3-4.5 hours (45%), 4.5-6 hours (28%), and >6 hours (10%). Meanwhile, in the double lung transplant cohort, ischemic time subgroups were as follows: <4.5 hours (26%), 4.5-6 hours (39%), and >6 hours (35%). Results Ischemic time had no impact on survival following single lung transplantation whether defined categorically (P=0.546) or continuously (HR, 0.986; 95% CI, 0.960-1.011; P=0.272). However, ischemic time was associated with significantly reduced survival following DLT in both definitions (P<0.001). After adjustment for potential confounders, the difference remained significant (HR, 1.041; 95% CI, 1.023-1.059; P<0.001). Conclusion The results of this large contemporary cohort suggest that the relationship between graft ischemic time and 1 year all-cause survival is not uniform across lung transplant types. Ischemic time was significantly associated with risk of reduced survival in double lung but not single lung transplant recipients. Both graft type and ischemic time should be incorporated in the decision-making process. Currently accepted clinical guidelines recommend ischemic times of no longer than four to six hours. To maximize organ supply, ischemic times beyond this are sometimes necessitated. We sought to determine whether graft ischemic time is independently associated with all-cause survival in a large, contemporary cohort of single and double lung transplant recipients. Data from adults undergoing initial isolated lung transplantation in the UNOS (United Nation for Organ Sharing) registry from January 2010 to December 2017 were included and compared for all-cause mortality at 1 year. Within single lung transplants, patients were further stratified into 3 ischemic time groups: <3 hours (17%), 3-4.5 hours (45%), 4.5-6 hours (28%), and >6 hours (10%). Meanwhile, in the double lung transplant cohort, ischemic time subgroups were as follows: <4.5 hours (26%), 4.5-6 hours (39%), and >6 hours (35%). Ischemic time had no impact on survival following single lung transplantation whether defined categorically (P=0.546) or continuously (HR, 0.986; 95% CI, 0.960-1.011; P=0.272). However, ischemic time was associated with significantly reduced survival following DLT in both definitions (P<0.001). After adjustment for potential confounders, the difference remained significant (HR, 1.041; 95% CI, 1.023-1.059; P<0.001). The results of this large contemporary cohort suggest that the relationship between graft ischemic time and 1 year all-cause survival is not uniform across lung transplant types. Ischemic time was significantly associated with risk of reduced survival in double lung but not single lung transplant recipients. Both graft type and ischemic time should be incorporated in the decision-making process.