Improved 2-year heart transplant survival with moderate hypothermic donor heart preservation in the GUARDIAN heart registry

BACKGROUND: Multiple advanced preservation technologies are now available and have demonstrated utility in organ assessment and preservation. The Paragonix SherpaPak Cardiac Transport System (SCTS) has become the most common method of static preservation, demonstrating superior outcomes to historic ice storage. To date, no preservation method has reported improved post-transplant survival. METHODS: Data from the GUARDIAN-Heart Registry, the largest real-world registry focused on organ preservation, were analyzed to quantify post-transplant clinical outcomes and survival in transplant cases utilizing ice cooler storage or moderate hypothermic preservation using SCTS. The independent contributions of the organ preservation method on outcomes, including severe primary graft dysfunction (PGD), right ventricular dysfunction (RVD), and mortality, were analyzed using propensity matching and logistic regression. RESULTS: Among 1,261 US adult heart transplants performed between October 2015 and January 2024, SCTS utilization was associated with significant reductions in incidence of severe PGD (Ice 10.8% vs SCTS 6.8%, p = 0.015) and severe RVD (Ice 9.9% vs SCTS 6.1%, p = 0.022). SCTS use was identified as an independent predictor of severe PGD (Odds Ratio = 0.60, p = 0.012) and severe RVD (OR = 0.75, p = 0.047). In the propensity-matched cohort, SCTS utilization was associated with a significant reduction in mortality after 2 years (Ice 10.5% vs. SCTS 5.7%, p = 0.042), and the Kaplan-Meier survival probability over 2 years was significantly higher in the SCTS cohort (p = 0.022). CONCLUSIONS: Moderate, controlled hypothermic preservation using SCTS significantly improves post-transplant outcomes and 2-year survival. This is the first study of any advanced heart preservation modality to demonstrate a significant impact on transplant survival.