Renal Histopathology and Outcomes in Simultaneous Liver-Kidney Transplantation

Background: Kidney biopsy findings with renal outcomes after simultaneous liver-kidney transplant (SLKT) are not well characterized in the current literature. We report, to our knoweldge, the first such dataset of it's kind. Methods: Patients were identified using ICD-10 and CPT codes. Renal parenchymal disease was identified by a pathologist. Weighted averages were used to determine mean and standard deviation. Results: 107 patients underwent SLKT between January 1, 2000 and December 31, 2023 at our institution. 27 kidney biopsies were performed in 22 patients, 5 patients had 2 biopsies. Liver transplant was performed for alcohol related cirrhosis (36%), metabolic dysfunction-associated steatohepatitis (MASH) (13.6%) and primary sclerosing cholangitis (13.6%), amongst others. Simultaneous kidney transplant was performed for hepatorenal syndrome (50%) and ESRD (36%), amongst others. Kidney biopsy was performed for declining kidney function (16), delayed graft function (5) and positive donor specific antibodies (2). 36% of patients had acute renal rejection, 32% had acute kidney injury, 14% had BK virus nephropathy, 9% had FSGS, 7% were not significant. Moderate to severe interstitial fibrosis and tubular atrophy was reported in 2 biopsies (7%). 86% of patients had some form of CKD and 32% were deceased by the end of the study period. Conclusion: Despite an average of 750 SLKTs being done per year since 2017, data on renal histopathology in this cohort is sparse. In our cohort, the rates of acute rejection and BK virus nephropathy were unexpectedly high. A better understanding of underlying renal pathologies may improve peri- and post-transplant management of renal disease.