Abstract and Introduction
Although previous consensus recommendations have helped define patients who would benefit from simultaneous liver–kidney transplantation (SLK), there is a current need to reassess published guidelines for SLK because of continuing increase in proportion of liver transplant candidates with renal dysfunction and ongoing donor organ shortage. The purpose of this consensus meeting was to critically evaluate published and registry data regarding patient and renal outcomes following liver transplantation alone or SLK in liver transplant recipients with renal dysfunction. Modifications to the current guidelines for SLK and a research agenda were proposed.
The model for end-stage liver disease (MELD) scoring system was implemented in 2002 and has been widely accepted as an objective scale of disease severity and accurate predictor of liver waitlist mortality. Prioritization of liver transplant candidates with renal dysfunction by the MELD system has resulted in a substantial increase in the number of simultaneous liver–kidney transplants (SLK) (Figure 1). Moreover, there exists a significant variability in the rate of SLK transplantation across the United States and Organ Procurement and Transplantation Network (OPTN) regions, which could be related to the acuity of patients on the waitlist in each region (Figure 2). This has raised concerns for two reasons: (1) the incremental benefit attributable to the kidney transplant in SLK recipients is unknown and difficult to assess; (2) SLK diverts deceased donor kidneys away from candidates for kidney transplant alone, which has created a vigorous debate about best use of organs and the ethical ramifications of allocating kidneys not only to liver-transplant candidates, but other extrarenal transplant candidates as well.
Total number and percentage of simultaneous liver–kidney transplantation (SLK) of all deceased donor, adult liver transplantation. Model of the end-stage liver disease (MELD) score was implemented in February 2002. Data from Organ Procurement and Transplantation Network (OPTN) as of June 2011 (http://optn.transplant.hrsa.gov).
Percentage of simultaneous liver-kidney transplantation of all deceased donor, adult liver transplantation in each Organ Procurement and Transplantation Network (OPTN) region from 2002–2010. Model of the end-stage liver disease (MELD) score was implemented in February 2002. Data from OPTN as of June 2011 (http://optn.transplant.hrsa.gov).
There are currently no standard criteria for the evaluation of patients with acute kidney injury (AKI) or chronic kidney disease (CKD) requiring liver transplantation (LT). The decision to perform SLK is generally driven by concern over the likelihood of recovery of renal function and the associated increase in mortality in patients with nonrecovery of renal function following liver transplantation alone (LTA). Because the persistence of preoperative renal dysfunction following LT has been associated with inferior patient survival combined with the fact that kidney waitlist survival is comparatively worse for candidates with a previous LT, transplant programs often follow center-specific decision making oriented toward ensuring adequate posttransplant renal function while considering the appropriateness of SLK. To this point, results of a recent survey completed by the Medical Directors of the Kidney Transplant Programs of US centers that perform SLK showed wide variability in criteria used for SLK and incongruity with the current published recommendations or the proposed OPTN listing criteria for SLK.
While performing an unnecessary SLK takes away available kidneys for recipients awaiting kidney transplant alone, failing to restore renal function may jeopardize the life of the liver recipient. Establishing transplant algorithms for dual organ failure depends on our ability to predict whether renal function will improve, stabilize or continue to deteriorate following transplantation in patients with renal dysfunction at the time of LT. However, the key determinants of renal nonrecovery with a high degree of predictive value remain poorly defined. Few studies exist on the natural history of renal failure in the setting of liver failure and subsequent LT to support a universal algorithm that serves the patient yet preserves kidney resources. Assessing the cause, duration, severity and chronicity of pretransplant renal dysfunction as well as intra- and postoperative events that impact renal recovery are the crucial questions remaining to be answered prior to developing a robust algorithm for selection of candidates for SLK.
Currently there are several pitfalls in the existing guidelines that make it difficult to accurately distinguish candidates who will benefit from SLK from those who will not. These include the definition and duration of AKI, glomerular filtration rate (GFR) determination and the duration of dialysis. In this light, a diverse panel of transplant and nontransplant physicians from pertinent fields assembled in Los Angeles, CA in 2011 to review the most recent guidelines, OPTN proposed policy on SLK and recent published literature and to determine if there is enough valid data upon which to recommend changes in clinical practice. The attendees were representatives from the OPTN liver and kidney committees, from various OPTN regions, mainly regions with high acuity liver transplant candidates and participants in previous consensus conference with expertise in SLK. The final summary statements from this group and directions for future research are the basis for this paper.