Background: Ex-vivo Normothermic Machine perfusion (NMP) has been shown to improve transplantation outcomes and assess the viability of discarded grafts. We report an application of NMP in assessing renal allograft viability in a case of renal vein thrombosis (RVT) following deceased renal transplantation in the immediate postoperative period.

Method: A 44-year-old female patient of unknown cause chronic kidney disease, on maintenance haemodialysis since 2018, underwent a deceased donor renal transplant from a young adult male donor after negative virtual crossmatch with CIT of 7 hrs 8 min. She had a history of fistula failure on multiple occasions and one abortion; her pro-coagulant workup was negative. She was on peritoneal dialysis for the past year, and she had multiple anti-HLA antibody specificities in class I and II loci (highest MFI 9709). She received Induction ATG, tacrolimus, mycophenolate, and steroids. The surgical procedure required reconstruction of the right renal vein. Allograft function was immediate and good with nadir creatinine 1.0mg/ml on postoperative day 6. On day 7, she had rapid onset anuria. Ultrasonogram showed clots in the graft pelvis with flow reversal, and CT angiogram showed RVT. On surgical re-exploration, the graft was congested, and the renal vein had an occlusive thrombus. After explantation and thrombectomy, the graft was placed on the Organ AssistTM using a red cell-based perfusate. It was perfused for six hours to check for graft viability on which there was the restoration of blood flow as evidenced by improving vascular resistance (peak 3mmHg/ml/min dropping to 1.3mmHg/ml/min) and blood flow (20ml/min rising to 220ml/min) and stabilization of lactate levels with a good macroscopic appearance. However, there was persistent haemorrhagic urine output despite an adequate and steady increase in renal blood flow.

Result: Despite demonstrating viability on NMP, the allograft could not be re-implanted due to haemorrhagic urine output on NMP, given the potential for bleeding and the hemodynamic instability in the recipient. The recipient was discharged on day 18 on dialysis. The allograft nephrectomy specimen showed isolated vascular acute T cell-mediated rejection- C4d negative with superimposed venous thrombosis.

Conclusion: EVNMP can help decision making in complex situations where graft viability assessment is not readily apparent.