Significant Dysfunction of Kidney Grafts Exposed to Prolonged Warm Ischemia Is Minimized Through Normothermic Ex Vivo Kidney Perfusion

Normothermic ex vivo kidney perfusion (NEVKP) is an emerging technique for renal graft preservation. We investigated whether NEVKP could improve early function of severely injured grafts and reduce the incidence of significant renal dysfunction (SRD) similar to delayed graft function in a model of donation after circulatory death. METHODS. Kidneys from 30-kg Yorkshire pigs were removed following 120 minutes of warm ischemia (WI). These grafts were then preserved in static cold storage (SCS, n = 6) or subjected to NEVKP (n = 5) for 8 hours before heterotopic autotransplantation. SRD was defined as postoperative day (POD) 4 oliguria <500 mL/24 h with serum K +> 6.0 mmol/L. RESULTS. All 4 surviving animals with 120 minutes WI grafts stored with SCS developed SRD, compared with 1/5 in the NEVKP group (P = 0.02). The NEVKP group, when compared with SCS, also demonstrated significantly decreased serum creatinine peak values (1118.51 ± 206.90 µmol/L versus 1675.56 ± 98.15 µmol/L; P = 0.002) and higher creatinine clearance (POD4: 9.05 ± 6.97 mL/min versus 0.89 ± 0.56 mL/min; P = 0.05). By POD7, serum creatinine was not significantly different than baseline in the NEVKP (431.49 ± 492.50 µmol/L versus 90.19 ± 14.15 µmol/L, respectively; P = 0.20) but remained elevated following SCS (1189.25 ± 309.47 µmol/L versus 97.26 ± 29.18 µmol/L, respectively; P < 0.01). Histology demonstrated significantly decreased tubular injury scores compared with SCS grafts (P = 0.03). CONCLUSIONS. Kidney grafts subjected to 120 minutes WI before retrieval showed significant improvement in function, prevention of SRD, and decreased injury following 8 hours of NEVKP.