Hypothermic Ex Vivo Perfusion Preserves Post-Transplant Donor Cardiac Function

Introduction: In heart transplantation (HTx), cold static storage (CSS) is the standard method used to preserve donor hearts. However, CSS beyond 4 hours increases the risk of primary graft dysfunction (PGD) in the recipient. Hypo- thermic ex vivo perfusion (HEVP) of donor hearts allows continued oxygen delivery during heart preservation and may thus facilitate extended donor heart preservation without increasing the risk of PGD. We sought to compare cardiac function post-transplant following donor heart preservation using CSS versus HEVP. Methods: Fifteen healthy female sheep were monitored for 24 hours, their hearts were then preserved by a) 2 hours CSS (n=7), b) 2 hours HEVP (n=4), or c) 8 hours HEVP (n=4). Orthotopic heart transplantation was performed in matched recipients, and following weaning from cardiopulmonary bypass, animals were monitored for 6 hours. Changes in left ventricular (LV) function were determined 6 hours post-HTx using echocardiography, and cardiac troponin levels measured. Vasopressor support was reflected by the vaso- pressor dependency index (VDI). Results: HEVP significantly improved post-HTx survival out to 6 hours (CSS: 57% vs 100% for HEVP groups). Post- HTx LV function (fractional area change–FAC; and global circumferential strain - GCS) is better preserved using 2 or 8 hours HEVP compared to CSS. HEVP reduced the require- ment for vasoactive support, but cardiac troponin levels were no different between groups. Conclusion: These results indicate that donor heart pres- ervation using HEVP may safely extend donor heart ischemic time without increasing the risk of early PGD.