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.