Out of the Ice Age: Preservation of Cardiac Allografts with a Reusable 10 °C Cooler

Objective: Static cold storage with ice has been the mainstay of cardiac donor preservation. Early preclinical data suggest that allograft preservation at 10 °C may be beneficial. We tested this hypothesis by using a static 10 °C storage device to preserve and transport cardiac allografts.

Methods: In total, 52 allografts were recovered between July 2023 and March 2024 and transported using a 10 °C storage cooler. Results were compared to a 3:1 propensity match of allografts transported on ice. Patients were excluded for the following reasons: dual viscera transplant, previous heart transplant, complex congenital heart disease, or allograft injury during procurement.

Results: Among the 10 °C cooler cohort, median total ischemic time was 222 minutes at 10 °C versus 193 minutes on ice ( < .0001). Intraoperative change in lactate was statistically lower at 10 °C (3.6 vs 5.1 mmol/L,  = .0016). Cardiac index score was greater in 10 °C cooler hearts at 24 (3.2 vs 3.0,  = .016) and 72 hours (3.3 vs 2.9,  = .037), despite similar vasoactive inotrope scores. There was no difference in severe primary graft dysfunction (1.9 vs 2.6%,  > .99). 10 °C hearts demonstrated less change in lactate but no difference in vasoactive inotrope scores or cardiac index. In hearts with extended ischemic time, delta lactate was lower in 10 °C cooler hearts. There was no statistical difference in outcomes for donor hearts >40 years old.

Conclusions: This is an early experience of static preservation in a 10 °C cooler. Postoperative allograft function was excellent, and lactate profiles lower in those allografts with extended ischemic times. Static cold storage targeting 10 °C may offer an inexpensive method for extended heart preservation. Further investigation is needed to assess long-term outcomes of 10 °C storage.