Margreiter and colleagues performed the first simultaneous liver–kidney transplant (SLK) in 1983.1 The number of SLK transplants has increased over 300% since the establishment of the Model of End-Stage Liver Disease (MELD) scoring system. The MELD scoring system was instituted in 2002.2 SLK transplants have increased from 1.7% of all liver transplants (LT) in the United States in 1990 to 9.9% in 2016.3–5
The indications to perform simultaneous transplantation continue to evolve and are not clear. One of the reasons for the increased interest in performing more SLK has been attributed to worse outcomes and poorer graft and patient outcomes in LT recipients with renal dysfunction.6–9 However, it is also known that renal dysfunction in itself can affect mortality after LT, especially in patients who are already requiring hemodialysis.10 Both the pretransplant and posttransplant creatinine are predictors of mortality in orthotopic liver transplantation (OLT).
Since 2002, there have been 2 consensus conferences organized by the American Society of Transplant Surgeons (ASTS), American Society of Transplant (AST), United Network of Organ Sharing (UNOS), and American Society of Nephrology (ASN). The first consensus conference established guidelines for the evaluation, listing, and transplant of patients with end-stage liver disease (ESLD) and chronic kidney disease (CKD) or end-stage renal disease (ESRD).11 The second consensus conference critically evaluated the published registry data, particularly focusing on patient and renal outcomes in LT recipients.12 There are much-needed ethical and moral discussions involving the best allocation of scarce organs. The typical SLK recipient receives a kidney from a deceased donor with a Kidney Donor Profile Index (KDPI) of less than 35%.13 In other words, the kidney allograft is from younger deceased donors that may benefit a pediatric or younger kidney transplant alone (KTA) recipient. There is variation in the way that SLK is practiced among LT centers. In an attempt to decrease this variation and ensure fair utilization UNOS introduced formal criteria for SLK listing on August 10, 2017.14 In addition a “safety net” was created to help LT-alone candidates who developed kidney failure with a glomerular filtration rate (GFR) <20 L/min within 60 days to the first year posttransplant. These patients are given priority in the sequence for kidney allocation. Whether this policy has indeed achieved its set goals or if it needs further revision is still under investigation.
PREVALENCE OF CHRONIC KIDNEY DISEASE IN LIVER TRANSPLANT CANDIDATES
The true prevalence of ESRD among patients with ESLD is unknown. In a retrospective study by Chen et al. (2015) of 2862 OLT performed in Taiwan, 214 developed acute kidney injury (AKI) in the post-OLT period.15 The patients that developed AKI post-OLT were older, had a higher risk of preoperative hypertension (26.64% vs. 19.98%, p = 0.0150), and were more likely to have a history of cerebrovascular events in the preoperative period (6.07% vs. 2.76%, p...