Ex vivo heart perfusion offsets ischemic penalties with ≥6-hour preservation in adult donation-after-brain-death heart transplantation.

Abstract

The 2018 United Network for Organ Sharing allocation revision broadened sharing and lengthened preservation. Survival declines after 4 hours of cold ischemia, with sharper losses beyond 6 hours. Ex vivo heart perfusion may mitigate this risk, but real-world effectiveness in the United States is uncertain. We analyzed adult heart transplants in the United Network for Organ Sharing (January 1, 2019, to April 1, 2025). We studied donation-after-brain-death hearts with preservation ≥6 hours, comparing ex vivo heart perfusion with no ex vivo heart perfusion (pooled static and hypothermic cold storage). The primary outcome was 1-year mortality; secondary outcomes were 90-day and 3-year mortality, postoperative complications, and cause of death. Analyses included Kaplan-Meier estimates, Cox regression, restricted cubic splines, and 1:1 propensity matching. Of 16,859 donation-after-brain-death recipients, 546 had preservation ≥6 hours (ex vivo heart perfusion n = 320; no ex vivo heart perfusion group n = 226). One-year survival was higher with ex vivo heart perfusion (92.5% vs 86.3%, P = .029) and at 3 years (90.9% vs 79.6%, P < .001). In adjusted models, the no ex vivo heart perfusion ≥6 hours group had greater 1-year mortality than ex vivo heart perfusion ≥6 hours (hazard ratio, 1.90, 95% CI, 1.08-3.35, P = .027). In a 4-level model, ex vivo heart perfusion ≥6 hours had outcomes comparable to the ex vivo heart perfusion <6 hours group and the no ex vivo heart perfusion <6 hours group, with excess risk confined to the no ex vivo heart perfusion ≥6 hours group. Splines showed rising mortality with longer preservation in the no ex vivo heart perfusion group and attenuation with ex vivo heart perfusion. Postoperative complications and cause of death were similar. Benefits concentrated at higher-volume centers. In contemporary US practice, ex vivo heart perfusion was associated with improved survival for ≥6-hour preservation, particularly at high-volume programs, mitigating the survival penalty from prolonged preservation.