Effects of Ischemic Time on Survival After Cardiac Transplantation in a Contemporary Cohort

Abstract

Purpose Limited availability of cardiac allografts and the risk of recipient waitlist mortality incentivizes expansion of the donor pool outside of the recommended maximum four hour ischemic time. We aimed to investigate whether prolonged donor ischemic time is associated with all-cause mortality after heart transplant in a modern cohort. Methods Data from initial isolated orthotopic cardiac transplantations performed on adult recipients from 2010 and 2017 reported to the United Network for Organ Sharing (UNOS) registry were analyzed. Patient survival rates at 1, 3, and 5 years were estimated using Kaplan-Meier with log-rank test. Subjects were stratified into four groups based on ischemic time: <3 hours (2.2 ± 0.55 hours, 21.1%) 3-4.5 hours (3.69 ± 0.42, 24.4%), 4.5-6 hours (5.16 ± 0.43, 10.5%), and >6 hours (7.44 ± 1.66, 6.2%). Results The median ischemic time was 3.55 (2.68, 4.63) hours. Prolonged ischemic time was associated with worse outcomes at 1 year (P<0.001), 3 years (P<0.001), and 5 years (P<0.001) in Kaplan-Meier analyses. Comparison to historical data suggests that advances in management have been unable to attenuate the hazard associated with longer ischemic times. Conclusion While concerns over ischemic time duration have persisted since the 1970s when institutions began exploring long-distance organ procurement as a means of expanding the donor pool, these data are among the first to show that extended ischemic times are significantly associated with short- and long-term all-cause mortality in a contemporary cohort. Anticipated ischemic time must be considered when assessing a potential donor. Further research is warranted to determine precise guidelines. Limited availability of cardiac allografts and the risk of recipient waitlist mortality incentivizes expansion of the donor pool outside of the recommended maximum four hour ischemic time. We aimed to investigate whether prolonged donor ischemic time is associated with all-cause mortality after heart transplant in a modern cohort. Data from initial isolated orthotopic cardiac transplantations performed on adult recipients from 2010 and 2017 reported to the United Network for Organ Sharing (UNOS) registry were analyzed. Patient survival rates at 1, 3, and 5 years were estimated using Kaplan-Meier with log-rank test. Subjects were stratified into four groups based on ischemic time: <3 hours (2.2 ± 0.55 hours, 21.1%) 3-4.5 hours (3.69 ± 0.42, 24.4%), 4.5-6 hours (5.16 ± 0.43, 10.5%), and >6 hours (7.44 ± 1.66, 6.2%). The median ischemic time was 3.55 (2.68, 4.63) hours. Prolonged ischemic time was associated with worse outcomes at 1 year (P<0.001), 3 years (P<0.001), and 5 years (P<0.001) in Kaplan-Meier analyses. Comparison to historical data suggests that advances in management have been unable to attenuate the hazard associated with longer ischemic times. While concerns over ischemic time duration have persisted since the 1970s when institutions began exploring long-distance organ procurement as a means of expanding the donor pool, these data are among the first to show that extended ischemic times are significantly associated with short- and long-term all-cause mortality in a contemporary cohort. Anticipated ischemic time must be considered when assessing a potential donor. Further research is warranted to determine precise guidelines.