195RECOVERY OF HEARTS FROM NON-HEART BEATING DONORS WITH NORMOTHERMIC EXTRACORPOREAL MACHINE PERFUSION

Objectives: To assess whether normothermic ex vivo machine perfusion may be used to improve the viability of hearts from non-heart beating donors. Methods: Hearts (n = 50) from male Lewis rats (350-40 g) were subjected to 25 min of global in situ warm (37°C) ischaemia. After explantation, the hearts were reperfused for 60 min at 37°C with diluted autologous blood. Subsequently, they were stored in Custodiol preservation solution at 4°C for four hours. Fresh excised hearts and ischaemic hearts, both stored in Custodiol, were used as controls. Graft function was assessed in a blood perfused Langendorff circuit. Perfusate was sampled to measure the levels of Troponin-T, creatine-kinase (CK), and lactate-dehydrogenase (LDH). From each group, a number of hearts (n = 6) were not reperfused, but snap frozen for analysis of adenosine-tri-phosphate (ATP) levels. Results: Compared to ischaemic controls, reperfused ischaemic hearts showed improved micro- and macroscopic appearance, faster recovery of heart rate, higher average heart rate (145.80 ± 7.31 vs 99.76 ± 24.99/min P < 0.05), a higher contractility index (6.05 ± 2.95 vs 3.15 ± 0.76 P < 0.05) and fewer arrhythmias. Perfusate levels of Troponin-T (164.85 ± 145.42 vs 308.54 ± 275.23 µg/l P = 0.22), CK (136.5.00 ± 86.59 vs 414.33 ± 455.97 U/l P = 0.11) and LDH (1814 ± 1394.11 vs 4098.83 ± 2548.30 U/l P = 0.05) were lower, and tissue ATP levels were higher (5.75 ± 1.97 vs 3.93 ± 0.96 m P < 0.05). Compared to fresh controls, reperfused ischaemic hearts demonstrated no significant difference (P > 0.05) in average heart rate and contractility. However, perfusate levels of Troponin-T, CK and LDH were higher and ATP was lower, but this difference was not statistically significant. Conclusions: Our results indicate that 60 min of normothermic reperfusion replenishes intracellular ATP levels and ameliorates the negative impact of 25 min of global warm ischaemia. A similar approach may be used to enable safe transplantation of hearts from non-heart beating donors.