Renal outcomes of liver transplant recipients who had pretransplant kidney biopsy

Background. Kidney biopsy has been recommended to guide kidney allocation in selected liver transplant (LT) candidates with renal dysfunction. However, postYLT-alone renal outcomes in recipients who showed evidence of reversible renal injury and limited chronicity on pre-LT kidney biopsy are unclear. Methods. Renal outcomes of 41 LT recipients who had pre-LT kidney biopsy for unexplained renal dysfunction, proteinuria, and hematuria were retrospectively reviewed. All biopsies showed less than 30% interstitial fibrosis and less than 30% to 40% glomerulosclerosis. Study endpoints were renal replacement therapy (RRT) at 1 month and the need for kidney transplantation at 1 year from LT. Results. Six patients were on RRT at time of biopsy. Median (range) iothalamate glomerular filtration rate and 24-hr urinary protein excretion for the remaining 35 patients were 29 (6Y88) mL/min per 1.73 m2 and 65 (0Y4,338) mg/day, respectively. Glomerulonephritis and acute tubular necrosis were present in 28 (68%) and 16 (39%) of the cases. Six patients (15%) did not recover kidney function at 1 month and RRT at time of LT was the only factor associated with this endpoint (P=0.04). Seven of the 31 (22%) patients with 1-year data met criteria for kidney transplantation within the first post-LT year. Surgical re-exploration was the only factor associated with the need for kidney transplantation at 1 year (P=0.05). Conclusions. The most LT recipients with minimal chronic changes on pre-LT kidney biopsy recovered kidney function within 1 month from LT. A small but significant percentage met criteria for kidney transplantation at 1 year because of the development of unforeseen post-LT complications.