Successful Transplantation of Human Kidneys Deemed Untransplantable but Resuscitated by Ex Vivo Normothermic Machine Perfusion

We report the successful transplantation of a pair of human kidneys that were declined for transplantation due to inadequate in situ perfusion but subsequently transplanted after perfusion and assessment using ex vivo normothermic perfusion (EVNP). The kidneys were from a 35-year-old man, a donation after circulatory death donor. Both kidneys were declined by all UK transplant centers. On arrival, the kidneys had significant areas of incomplete clearance of blood from the microcirculation that did not clear after a further attempt to flush them. Kidneys underwent 60 min of EVNP with an oxygenated packed red blood cell-based solution warmed to 35.2 degrees C. During EVNP, the patchy areas cleared in both kidneys. The mean renal blood flow and total urine output were 68.0 mL/min/100 g and 560 mL in the left kidney and 59.9 mL/min/100 g, 430 mL in the right, respectively. Based on the EVNP perfusion parameters, both kidneys were deemed suitable for transplantation. They were transplanted without any complications, and both recipients had initial graft function. The serum creatinine levels at 3 months were 1.2 mg/dl in the recipient of the left kidney and 1.62 mg/dl in the recipient of the right kidney. EVNP technology can be used to assess and rescue kidneys previously deemed unsuitable for transplantation.