J. Rosado1, A. Fano1, N. Dhaduk1, G. Dikdan1, J. V. Guarrera1 1Rutgers New Jersey Medical School,Surgery,Newark, NJ, USA
Introduction: While the “gold standard” for preservation of donor livers is static cold storage (SCS), recently hypothermic machine perfusion (HMP) has entered the clinical arena. Furthermore, the role of oxygenation in machine perfusion has been a subject of debate. Current devices for HMP require the use of continuous O2 via an oxygenator which is cumbersome and limit ability to travel. Our group’s prior work has shown improved outcomes and utilization of “marginal” livers with HMP without active oxygenation. We developed a novel approach to oxygenation using a perfusate “pre-charge” in conjunction with our closed portable perfusion device. The aims of the study were to: 1) Evaluate HMP in a porcine model of DCD recovery and preservation by evaluating perfusate markers. 2) Evaluate the efficiency and effects of O2 delivered with a novel technique of oxygen “pre-charge”.
Methods: 23 Porcine livers where obtained from a local USDA slaughterhouse. In this protocol livers mimic a model of DCD procurement due to the warm ischemia time. Livers were flushed with UW on site roughly 20 min after slaughter via the Portal vein and Hepatic artery and underwent (SCS) during transport to our laboratory. Livers were placed into one of 4 treatment arms: SCS (8 livers), HMP with oxygen pre-charge (HMP-O2) (5 livers), HMP without oxygen with inner lid on (HMP-L) (5 livers), or HMP with inner lid off open to air (HMP-A) (5 livers). All HMP was carried out using the ORS LifePort liver transporter using Vasosol™ solution at 4ºC. Pre-charge of the solution was performed using O2 running at 10L/min over 15 mins. SCS and HMP were undertaken for 4hrs from the time of arrival at lab. Measurements for oxygen levels in the perfusate and within tissue were recorded. Perfusate samples were obtained at 0, 2hr, and 4hrs and analyzed for AST, ALT, and LDH levels as markers for liver injury.
Results: ALT showed a decrease in all HMP groups compared to SCS in the final time point, and was statistically significant in the HMP-O2 and HMP-L groups (SCS = 20.24, HMP-L=9.26 p=0.011, HMP-A=14.0 p=0.22, HMP-O2=9.18 p=0.019). LDH was also noted to be significantly in all HMP groups in comparison to SCS in the final time point (SCS = 3018.1, HMPL=1274.7 p=0.03, HMP-A=970.6 p=0.011, HMP-O2=1106.36 p=0.0451). AST levels were similar in all groups.
Conclusion: HMP appears to confer a protective advantage over SCS as evidenced by perfusate AST, ALT, and LDH levels. The technique of Oxygen Precharge is effective and not deleterious to the graft. This simplified approach may facilitate logistics and portability of HMP which would encourage further adoption in clinical liver transplantation.
