Renal Outcomes of Liver Transplant Recipients Who Had Pretransplant Kidney Biopsy Hani M. Wadei, 1,4 Michael G. Heckman, 2 Bhupendra Rawal, 2 C. Burcin Taner, 1 Martin L. Mai, 1 Cherise Cortese, 3 Barry G. Rosser, 1 Thomas A. Gonwa, 1 and Andrew P. Keaveny 1 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 m 2 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-LTyear. 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 functionwithin 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. Keywords: Hepatorenal syndrome, PreYliver transplant renal dysfunction, PreYliver transplant proteinuria, Kidney- liver transplantation. (Transplantation 2014;00: 00Y00) T he number of simultaneous liver-kidney transplants (SLK) has dramatically increased in the United States since the introduction of the model for end-stage liver disease (MELD) scoring system in early 2002. Consensus conferences and published guidelines have proposed listing criteria for SLK transplantation (summarized in TableS1, Supplemental Digital Content [SDC], http://links.lww.com/TP/A995) (1, 2). Nevertheless, SLK practice has not been standardized at a national level with significant variation in the number and percentage of SLK transplants performed in the US (3). This variability can be explained by the lack of accuracy of some of the SLK listing criteria: 40%Y50% of patients who meet these criteria and receive SLK demonstrate significant native renal function, whereas 40%Y76% of those who do not meet these criteria and still receive SLK experience no meaningful native renal recovery (4, 5). Current guidelines rely heavily on the duration of renal dysfunction (RD) to determine candidacy for SLK (6, 7). Some candidates however are referred to a liver transplant (LT) center with an RD of unknown duration ren- dering these guidelines inapplicable. In other situations, LT candidates have a mixed picture with RD, low fractional ex- cretion of sodium and presence of proteinuria and hematuria. In these cases, understanding whether the RD is caused by an CLINICAL AND TRANSLATIONAL RESEARCH Transplantation & Volume 00, Number 00, Month 00, 2014 www.transplantjournal.com 1 This study was supported by a research grant from the Mayo Clinic and Foundation. The authors declare no conflicts of interest. 1 Department of Transplant, Mayo Clinic, Jacksonville, FL. 2 Section of Biostatistics, Mayo Clinic, Jacksonville, FL. 3 Department of Laboratory Medicine and Pathology, Mayo Clinic, Jacksonville, FL. 4 Address correspondence to: Hani M. Wadei, M.D., Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224. E-mail: wadei.hani@mayo.edu H.M.W. participated in research design, data analysis, and writing of the article. M.H. participated in research design and data analysis. B.R. participated in research design and data analysis. C.B.T., M.M., C.C., M.R., and T.G. participated in research and article editing. A.K. participated in research design, performance of the research, and article editing. Supplemental digital content (SDC) is available for this article. Direct URL citations appear in the printed text, and links to the digital files are provided in the HTML text of this article on the journal’s Web site (www.transplantjournal.com). Received 14 February 2014. Revision requested 12 March 2014. Accepted 1 April 2014. Copyright * 2014 by Lippincott Williams & Wilkins ISSN: 0041-1337/14/0000-00 DOI: 10.1097/TP.0000000000000215 Copyright © 2014 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.