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

Abstract

ObjectiveStatic cold storage (SCS) with ice has been the mainstay of cardiac donor preservation. Early preclinical data suggest that allograft preservation at 10oC may be beneficial. We tested this hypothesis by using a static 10oC storage device to preserve and transport cardiac allografts. Methods52 allografts were recovered between July 2023 and March 2024 and transported using a 10oC storage cooler. Results were compared to a 3:1 propensity match of allografts transported on ice. Patients were excluded for the following: dual viscera transplant, previous heart transplant, complex congenital heart disease, or allograft injury during procurement. ResultsAmong the 10oC cooler cohort, median total ischemic time was 222 min at 10oC vs 193 min on ice (p<0.0001). Intraoperative change in lactate was statistically lower at 10oC (3.6 vs 5.1 mmol/L, p=0.0016). Cardiac index (CI) was higher in 10oC cooler hearts at 24 (3.2 vs 3.0, p=0.016) and 72 hours (3.3 vs 2.9, p=0.037), despite similar vasoactive inotrope scores (VIS). There was no difference in severe primary graft dysfunction (1.9 vs 2.6%, p>0.99). 10oC hearts demonstrated less change in lactate but no difference in VIS or CI. In hearts with extended ischemic time, delta lactate was lower in 10oC cooler hearts. There was no statistical difference in outcomes for donor hearts > 40 years old. ConclusionsThis is an early experience of static preservation in a 10oC cooler. Postoperative allograft function was excellent, and lactate profiles lower in those allografts with extended ischemic times. SCS targeting 10oC may offer an inexpensive method for extended heart preservation. Further investigation is needed to assess long-term outcomes of 10oC storage.