Early elevated donor-derived cell-free DNA levels in heart transplant recipients following precision-controlled cardiac transport system or ice-cooled organ transport.

Background: Recent innovations in temperature-controlled cardiac transportation allow for static hypothermic preservation of transplant organs during transportation. We assessed differences in donor-derived cell-free DNA (dd-cfDNA) using the SherpaPak cardiac transport system (SCTS) and traditional ice transportation.

Methods: Single-organ heart transplant recipients between January 2020 and January 2022 were included if they had dd-cfDNA measures ≤6 weeks post-transplant along with the baseline biopsy at 6 weeks as part of the surveillance protocol and no biopsy-confirmed rejection ≤90 days. Elevated dd-cfDNA ≥.20% were compared between groups using logistic regression including a subject effect.

Results: Of 65 hearts transplanted, 30 were transported with SCTS and 35 on ice. Recipient characteristics were similar between groups. Donors in the SCTS group were older (34 vs. 40 years, p = .04) with a longer total ischemic time (171 vs. 212 min, p = .002). Recipients in the SCTS group had a greater risk of elevated dd-cfDNA unadjusted and adjusted for donor age, and prolonged ischemic times > 3.5 h (Unadjusted odds ratio: 4.9, 95%-CI: 1.08-22.5, p = .039 and Adjusted odds ratio: 5.5, 95%-CI: 1.03-29.6, p = .046). Primary graft dysfunction rates and 1-year mortality were comparable between groups.

Conclusion: Elevated dd-cfDNA in patients procured with SCTS may indicate that graft injury was not negated relative to ice transport. However, there were no clinical differences noted in short or long-term outcomes including mortality despite a longer ischemic time in the SCTS group.