BackgroundEx situ heart perfusion (ESHP) has been used to optimize donor organs before heart transplantation. However, cardiac function often deteriorates with the development of myocardial edema. The use of dialysis during ESHP could assist in cardiac preservation. MethodsMale Yorkshire pig hearts were subjected to ESHP for 8 hours with or without dialysis. Hearts were supported during nonworking mode (NWM) and working mode (WM) and pressure-volume loops and coronary vasomotor function was evaluated. Finally, tissue biopsies were assessed for mitochondrial function, oxidative stress, and inflammation. ResultsAdding dialysis to ESHP significantly enhanced cardiac function, with improved PRSW at 4 hours (64.09 ± 20.13 vs. 35.08 ± 13.52, p = 0.010) and 8 hours (64.31 ± 9.08 vs. 23.30 ± 19.25, p = 0.0002), Emax at 8 hours (24.67 ± 10.75 vs. 10.62 ± 8.471, p = 0.0477), and EDPVR at 8 hours (644.7 ± 566.68 vs. 86.63 ± 72.05, p = 0.0187). Coronary vasomotor function improved in the dialysis group in endothelium dependent (LogIC50 -7.39 ± 0.25 vs. -2.22 ± 0.76, p < 0.0001) and independent (LogIC50 -6.11 ± 0.19 vs. -4.79 ± 0.11, p < 0.0001) vasorelaxation. Dialyzed hearts also had reduced sensitivity to ET1 (LogEC50 -7.94 ± 0.5 vs. -8.54 ± 0.06, p = 0.0449) and significant changes in endothelin receptor-related protein expression related and oxidative stress. ConclusionsThe combination of dialysis with ESHP improves myocardial and coronary vasomotor preservation and may allow for longer perfusion times.