Improved outcomes and donor utilization in heart transplantation with 10 °C static cold storage

To compare 10 °C static cold storage (SCS) with traditional ice for cardiac allograft preservation, its impact on post-transplant outcomes, and donor utilization.

We retrospectively analyzed adult heart transplants performed between January 2020 and December 2024. Allografts were preserved using either 10 °C cooler or ice. Multiorgan and congenital cases were excluded. Inverse probability of treatment weighting was used to adjust for baseline differences. Firth-corrected regression estimated independent association of 10 °C with outcomes, followed by machine learning validation. Interrupted time-series regression assessed changes in donor utilization and outcomes following adoption of 10 °C storage.

Among 442 recipients (median age 57.9 years, 25.3% female), 142 (32%) received grafts preserved at 10 °C and 300 (68%) on ice. Despite older donors and longer ischemic times (234 vs 202 min; p < 0.001), the 10 °C group had lower 24-hour lactate (8.0 vs 10.2 mmol/L; p = 0.001). After adjustment, 10 °C preservation was significantly associated with reduced severe PGD and 30-day mortality by 64% (relative risk 0.37; 95% CI 0.15-0.92; p = 0.03). Post-bypass RV dysfunction, need for renal replacement therapy, VIS at 24 h, and hospital stay were all lower (p <.05) In the 10 °C group. Adoption of 10 °C was significantly associated with increased cumulative donor risk (+0.86 points, p = 0.032) and reversed prior PGD trends (p = 0.04) without increasing mortality.

Static preservation at 10 °C was associated with significant reduction in ischemia-related injury, improved early post-transplant outcomes, and safe expansion of high risk donor acceptance. 10 °C storage represents an effective preservation modality that challenges ice as the default preservation method.