Residual Native Kidney Function after Kidney Transplant (KT): Unusual Complications

Introduction: Bartter syndrome, affects 1 in 1,000,000, presents challenges in KT recipients with residual native renal function. We present the clinical course of a KT recipient with suspected Bartter syndrome. Case Description: 26-year-old man with CKD V underwent a preemptive deceased donor KT. Kidney biopsy (bx) 7 years ago revealed interstitial nephritis with moderate fibrosis and tubular atrophy, attributed to prolonged NSAID use. He had persistent hypokalemia requiring supplementation. Post-transplant, he experienced slow graft function (SGF), serial allograft bx showed acute tubular injury. He received thymoglobulin induction and a calcineurin-inhibitor (CNI)-based maintenance immunosuppression regimen. Due to ongoing SGF with nadir creatinine (Cr) of 4, he was switched to a CNI-free regimen with Belatacept. His electrolyte profile showed hypokalemia, and a significant urine output of 3-5 L/day, requiring scheduled fluid administration after which Cr improved but plateaued at 3. Technetium-99m mercaptoacetyltriglycine perfusion scan (MAG3) with split function analysis showed a 32.6% contribution from native kidneys. raising suspicion of Bartter syndrome, with preserved native output leading to chronic hypovolemia and allograft dysfunction. Following multidisciplinary discussion, including the patient's input, native right renal artery embolization with 10 mL of Visipaque 270 was performed 9 months post-transplant. Procedure was tolerated well. Cr, 1 month after, improved to 2.9, with long term follow-up awaited. Discussion: Residual kidney function in tubulointerstitial, salt-wasting diseases can challenge KT, impending allograft function. In such disease, timing of KT is crucial. Delaying until no residual renal function or considering preemptive native nephrectomy may minimize allograft failure risk. Native kidney embolization is a minimally invasive alternative to nephrectomy, though its efficacy remains unproven in KT. We plan to update MAG3 to assess left native kidney function and consider contralateral embolization.Selective Native Renal Artery Embolization:Radiological Procedure