Prolonged ex-situ heart perfusion preserves cardiac output following orthotopic transplantation in a porcine model.

The safe ischemic window for static cold storage in heart transplantation is around 4-6 h, limiting donor retrieval distance and contributing to organ discard. We aim to assess whether a porcine heart preserved for 24 h using a novel ECMO-based ESHP system can maintain function after orthotopic transplantation. Five-orthotopic allogeneic heart transplantation were preserved for 24 h on a custom ECMO-based ESHP circuit at 37 °C, with coronary perfusion pressure 60-70 mmHg, and metabolic/hormonal supplementation. Hemodynamic, metabolic, and oxygenation parameters were measured using pulmonary arterial thermodilution via a Swan-Ganz catheter. Recipients were monitored for 4 h post-transplantation: cardiac output increased from 5.94 ± 0.16 L/min (baseline) to 6.78 ± 0.12 L/min (immediately post-transplant) (p = 0.006) and 7.06 ± 0.16 L/min at 4 h following transplantation (p = 0.017). Despite significant reductions in hemoglobin and arterial oxygen content, oxygen delivery remained adequate, oxygen consumption increased significantly at 4 h following transplantation to 172.88 ± 7.60 mL/min/m² (p = 0.0322 vs. donor) and lactate levels stayed low. No evidence of acute graft dysfunction was observed. Normothermic preservation of the heart with our institutional ESHP protocol for 24 h maintained graft viability and function in a porcine transplantation model.