Real-time Monitoring of Kidney Grafts on Hypothermic Machine Perfusion (REMO-HYMAP)

A Clinical Pilot Study Investigating the Real-time Dynamics of Glucose, Lactate and Creatinine Concentrations in Marginal Donor Kidneys Undergoing Hypothermic Machine Perfusion

A significant number of deceased donor kidneys donated for transplantation are not used and are thrown away due to lack of ways of checking their condition and function before the operation. This significantly reduces the number of potentially life saving transplants. The researchers wish to run a small pilot study to see if it is possible to improve the way transplant kidneys are assessed before transplantation by measuring how well they filter the blood, and how good their metabolism is. The researchers believe this new method will help transplant surgeons make better decisions about which kidneys to use. This pilot study will look at 10 kidneys obtained from older deceased donors. These kidneys are most at risk of being thrown away because of the condition of the donor they came from. At the hospital, these kidneys are usually put onto a machine which pumps cold preservation solution through them for a couple of hours. This time lets the transplant surgeons see how well or poorly the kidney responds to the flowing fluid. In this study the research team will do exactly the same, but also insert a small probe less than a millimetre in diameter into the kidney and the vein (draining blood pipe) and urine output to monitor a number of chemicals made by the kidney. The researchers believe that the changing levels of these chemicals will give the surgeons much more information than they have now. This probe is removed when the kidney is transplanted. Combining these levels with news of how well the patients recover after surgery will allow the research team to design a much larger study to get the right level of information to change the way surgeons choose kidneys and help more transplants happen in the future.

Transplant patients receiving kidneys from deceased marginal donors: aged >= 60, or >= 50 with comorbid renal impairment, hypertension, or cerebrovascular disease. Following consent, kidneys will be cold perfused with preserving solution for 2-4 hours as per standard of care at the study centre. During this period, the kidneys will be monitored for creatinine, glucose, and lactate concentrations using three microdialysis probes placed into the tissue, the vein, and the ureter. Data will be blinded to clinicians. The probes will be removed at the end of the perfusion period and the organs will be transplanted or discarded according to clinical protocol. If transplanted, the study will monitor the patient's recovery for the first 30 days.

Three microdialysis probes will be introduced into the kidney tissues, the vein and ureter in order to measure creatinine, glucose and lactate while the organ is undergoing cold perfusion prior to transplantation.

Magnitude of change in patient baseline serum creatinine concentration pre- and post-operatively at 30 days (in umol/L)

Number of participants with no change in serum creatinine concentration from baseline despite transplantation

Number of days with inadequate graft function following surgery (low urine output, static serum creatinine concentration)

Rates of the most common complications including arterial, venous, or parenchymal thrombosis, ureteric leak or stenosis

Inclusion Criteria: All organs to be used in the study must be intended for transplantation and not already rejected/discarded. All organs must be sourced from deceased donors through NHSBT in the normal course of clinical activity. Kidneys must come from marginal or 'imperfect' donors according to current clinical criteria. This typically indicates an age of 60 and over, or 50 and over with one or more premorbid conditions, including renal impairment, cerebrovascular disease, and hypertension. Exclusion Criteria: Organs from living donors are excluded. Organs from young healthy donors are excluded. Organs will be excluded if on the assessment of the clinical team they are not suitable for hypothermic machine perfusion. This indicates organs that have arrived with visible defects, or fall well outside the team's standard criteria for clinical acceptability (excessive time in transit, excessive warm ischaemia time, excessive cold ischaemia time, very poor pre-morbid donor condition).