What Is The Evidence For Oxygenated Hypothermic Machine Perfusion in Kidney Transplantation? A Systematic Review*.

Abstract

As the increasing demand for organs continues high risk donors represent an additional supply of organs to the donor pool. We systematically reviewed the evidence of ex-vivo hypothermic OMP in kidney donors. We searched Medline, Embase, Cochrane's CENTRAL and Transplant Library for human and animal studies on OMP alone or OMP compared with machine perfusion (MP) in kidney transplantation. Studies had to report patient/animal survival, discard rate, technical complications or renal function. Data were extracted regarding donors/recipients, oxygenation method, preservation time, perfusion temperature/pressure/flow, and outcomes. The search identified 2820 references of which 35 (18 case series, 11 cohort studies, 6 randomised controlled trials) met our inclusion criteria. Four studies were in humans and 31 in animals of which 20 were studies of auto-transplantation. Twelve animal studies in pigs (4), dogs (3), rats (4), and rabbits (1) compared OMP with MP and 23 studies in humans (4), pigs (5), dogs (11) and rats (3) reported on OMP alone. Seven methods of oxygenation were reported: ultrabaric oxygenation, membrane oxygenation, air pump oxygenation, retrograde persufflation, oxygenated persufflation, oxygenated machine perfusion and hyperbaric oxygenation/chamber. OMP was applied either continuously (8 studies) or at the end of the perfusion (27 studies). Perfusion temperature ranged 2-32°C and perfusion time 1-72 hours. There was one direct comparison of OMP and MP in pigs that reported on animal survival which showed rates of 100% for OMP versus 43% for MP. Two other studies (dogs, rats) showed survival rates of 0-100% for OMP and 0-80% for MP. Studies comparing OMP with MP showed conflicting results for renal function. There were no human trials comparing OMP with MP. Studies on OMP alone in humans showed patient survival rates of 50-100% (3 studies). OMP in animals led to survival rates of 0-100% (15 studies) with porcine studies showing survival rates of 33-100% (4 studies). The available evidence for oxygenated hypothermic machine perfusion is poor. There is inconclusive evidence that supplemental oxygenation during HMP improves early renal function. There is very little information from human studies. Thus good quality randomised controlled trials are essential to establish the role of oxygenation with machine perfusion. *Conducted as part of the Consortium for Organ Preservation in Europe (COPE), which is funded by an EU FP7 grant.