Room Temperature Pulsatile Perfusion of Renal Allografts With Lifor Compared With Hypothermic Machine Pump Solution F. Gage, D.B. Leeser, N.K. Porterfield, J.C. Graybill, S. Gillern, J.S. Hawksworth, R.M. Jindal, N. Thai, E.M. Falta, D.K. Tadaki, T.S. Brown, and E.A. Elster ABSTRACT This pilot study compared the use of the Lifor Organ Preservation Medium (RTLF) at room temperature with hypothermic Belzer machine preservation solution (CMPS) and room in vitro temperature Belzer machine preservation solution (RTMPS) in a porcine model of uncontrolled donation after cardiac death (DCD). In this study, 5 porcine kidneys for each perfusate group were recovered under a DCD protocol. The kidneys were recovered, flushed, and placed onto a renal preservation system following standard perfusion procedures. The average flow rate for CMPS was 36.2  7.2549 mL/min, RTMPS was 90.2  9.7159 mL/min, and RTLF was 103.1  5.1108 mL/min. The average intrarenal resistance for CMPS was 1.33  0.1709 mm Hg/mL per minute, RTMPS was 0.84  0.3586 and RTLF was 0.39  0.04. All perfusion parameters were statistically significant (P  .05) at all time points for the CMPS when compared with both RTMPS and RTLF. All perfusion parameters for RTMPS and RTLF were equivalent for the first 12 hours; thereafter, RTLF became significantly better than RTMPS at 18 and 24 hours. It appears that both RTMPS and RTLF have equivalent perfusion characteristic for the initial 12 hours of perfusion, but LF continues to maintain a low resistance and high flow up to 24 hours. The results of this pilot study indicate that RTLF may represent a better alternative to pulsatile perfusion with CMPS and requires validation in an in vivo large animal transplant model. D ESPITE SIGNIFICANT changes in immunosuppres- sive regimens, limited progress has been made in the science of organ preservation. 1 Currently, the 2 most com- mon solutions used for static cold preservation of renal allografts have been in use for 20 years, and neither has been shown to confer a significant advantage over the other. 2 We continue to have a practical limit of 24 – 48 hours of viable cold storage time. The alternative to cold renal storage, machine pulsatile perfusion (PP), has never been clearly shown to be superior to static preservation methods and uses similar preservation solutions. 3 The accepted prognosticating standards for renal perfusion have relied on intrarenal resistance (IR) of pumped kidneys since the mid 1980s when Henry et al 4 first reported their findings. Henry further reported that IR  0.250 mm Hg/mL per minute predicted an immediate functioning renal allograft, an IR of 0.250 – 0.400 mm Hg/mL per minute predicted delayed renal allograft function (the need for dialysis within the first week posttransplantation), and IR  0.400 mm Hg/mL per minute led to a primary nonfunctioning renal allograft. 4 Although cold PP is the current standard, studies of warm machine perfusion of organ allografts have resulted in deteriorating perfusion characteristics as manifested by an increasing intrarenal resistance and decreasing flow. 6 This effect is due to the failure to maintain the integrity of the vascular endothelium and an inability to deliver ade- quate amounts of nutrients and oxygen. 6 An alternative to cold PP is the use of a new perfusion agent, Lifor OPM (Lifeblood Medical, Freehold, NJ), which has been devel- oped to maintain organ integrity at room temperature. Lifor OPM is a novel agent that includes nutrients, amino From the Department of the Navy, Regenerative Medicine, Operational and Undersea Medicine Directorate, Naval Medical Research Center, Silver Spring, Maryland. This work was supported by work unit number: 602227D.0483.01.A0518 (MFEL). Address reprint requests to Eric Elster, MD, FACS, CDR MC USN, Naval Medical Research Center, Regenerative Medicine, Operational and Undersea Medicine, Directorate, 503 Robert Grant Avenue, 2W123, Silver Spring, MD. 20910. Published by Elsevier Inc. 0041-1345/09/$–see front matter 360 Park Avenue South, New York, NY 10010-1710 doi:10.1016/j.transproceed.2009.06.228 Transplantation Proceedings, 41, 3571–3574 (2009) 3571