Simultaneous liver kidney allocation policy and the Safety Net: an early examination of utilization and outcomes in the United States

Renal Dysfunction and Liver Transplantation

Renal dysfunction is common in patients undergoing liver transplant (LT) evaluation, thereby making it imperative for hepatologists to know how to diagnose, manage, and optimize treatment of acute kidney injury (AKI) and chronic kidney disease. This article reviews pre-transplant, peri-transplant, and post-transplant AKI diagnosis and management, and the role of renal replacement therapy in LT candidates.

Racial disparities in posttransplant outcomes among recipients undergoing simultaneous liver-kidney transplantation

BACKGROUND

Patients with end-stage cirrhosis may experience renal dysfunction, necessitating a simultaneous kidney-liver transplant (SKLT). Guidelines have been put forth by the United Network for Organ Sharing (UNOS) to streamline the SKLT allocation process and ensure equitable access to transplantation. However, there is a scarcity of literature on racial and ethnic disparities in post-SKLT outcomes.

METHODS

The UNOS Standard Transplant Analysis and Research Database was queried from 2005 to 2019 to study SKLT patients. Patients were stratified by race: White (reference group) recipients (n = 3513), Black recipients (n = 859), Hispanic recipients (n = 964), Asian recipients (n = 206), and other recipients (n = 85). Primary endpoints included all-cause mortality and graft failure while secondary endpoints were specific causes of death.

RESULTS

Hispanic recipients had a lower risk of all-cause mortality (aHR: 0.79, 95% CI: 0.68-0.93, P = 0.003), while Black recipients had a significantly increased risk of graft failure compared to Whites (aHR: 1.63, 95% CI: 1.16-2.30, P = 0.005). Evaluation of specific causes of recipient death revealed a higher risk of death due to gastrointestinal hemorrhage among Blacks (aHR: 4.16, 95% CI: 1.04-16.68, P = 0.04).

CONCLUSION

Our study findings show Black patients experience higher rates of graft failure compared to White counterparts. The reasons for these disparities are not fully understood but likely a combination of biological and social factors. Further investigation is warranted to ascertain the specific factors influencing these outcomes.

Factors Impacting Early Adverse Outcomes in Simultaneous Heart-Kidney Transplantation

BACKGROUND

Over the last decade, the number of simultaneous heart-kidney transplants (SHKTs) has increased dramatically. There are few reports of renal allograft outcomes in these high acuity patients. The goal of the present study was to identify variables that were related to early adverse outcomes (EAOs), including delayed graft function (DGF), primary non-function (PNF), and renal allograft futility (RAF) after SHKTs.

METHODS

We performed a single center retrospective review of all adults undergoing SHKTs from October 2011 to August 2021. Multivariable logistic regression models with backward elimination were used to test the relationships between recipient (pre-transplant dialysis, intra-aortic balloon pump, serum lactate, norepinephrine use, and re-do sternotomy) and operative (cold ischemia time [CIT]) variables and the likelihood of DGF, PNF, and RAF.

RESULTS

Sixty-eight patients underwent SHKT during the study period. Overall, patient survival was 87%, 83%, and 80% at 6 months, 1 year, and 3 years, respectively. Twenty-four patients (35%) experienced DGF, whereas 4 patients (6%) had PNF, and 12 patients (18%) had RAF (Table 1). Pre-transplant dialysis, serum lactate, and CIT were significantly associated with an increased likelihood of DGF. Norepinephrine (NE) and CIT were associated with increased likelihood of RAF (Table 2).

CONCLUSIONS

Pre-transplant dialysis is related to an increased likelihood of EAO following SHKT, with CIT and NE contributing to increased likelihood of RAF. Given that SHKT recipients are at risk of remaining on dialysis following SHKT, strategies that allow for expedited kidney transplantation after heart transplantation may mitigate the hemodynamic and ischemic constraints of SHKT that contribute to early adverse outcomes.

Dual organ transplantation: Pancreas and Liver in the kidney axis

PURPOSE OF REVIEW

This article explores the benefits and challenges of dual organ transplants.

RECENT FINDINGS

Simultaneous liver-kidney transplant has become a valuable option for patients with both liver and kidney failure, especially since the introduction of clearer eligibility guidelines in 2017. When done for the appropriate candidate, it can significantly improve survival and quality of life. Similarly, simultaneous pancreas-kidney transplantation provides significant advantages for patients with diabetes-related kidney failure by addressing both glycemic control and kidney function, with significant improvement in diabetes associated complications and survival.

SUMMARY

While these procedures are complex, they offer promising solutions for managing difficult multiorgan conditions. Ongoing research and personalized patient care will be key to maximizing their benefits.

Performance of race-neutral eGFR equations in patients with decompensated cirrhosis

The 2021 Chronic Kidney Disease Epidemiology Collaboration equation [CKD-EPI 2021] is a race-neutral equation recently developed and rapidly implemented as a reference standard to estimate glomerular filtration rate(GFR). However, its role in cirrhosis has not been examined especially in low GFR. We analyzed the performance of CKD-EPI 2021 compared to other equations with protocol-measured GFR (mGFR) in cirrhosis. We analyzed 2090 unique adult patients with cirrhosis undergoing protocol GFR measurements using iothalamate clearance from 1985 to 2015 when listed for liver transplantation at Baylor University in Dallas and Fort Worth, Texas. Using mGFR as a reference standard, the CKD-EPI 2021 was compared to CKD-EPI 2012, Modification of Diet in Renal Disease-4, Modification of Diet in Renal Disease-6, Royal Free Hospital, and GFR Assessment in Liver disease overall and in certain subgroups (ascites, mGFR ≤ 30 mL/min/1.73 m 2 , diagnosis, Model for End-Stage Liver Disease and gender). We examined bias (difference between eGFR and mGFR), accuracy (p30: eGFR within ± 30% of mGFR) and agreement between eGFR and mGFR categories. CKD-EPI 2021 had the second lowest bias across the entire range of GFR after GFR Assessment in Liver disease (6.6 vs. 4.6 mL/min/1.73 m 2 , respectively, p < 0.001). The accuracy of CKD-EPI 2021 was similar to CKD-EPI 2012 (p30 = 67.8% vs. 67.9%, respectively) which was higher than the other equations ( p < 0.001). It had a similar performance in patients with ascites, by diagnoses, Model for End-Stage Liver Disease subgroups, by gender, and in non-Black patients. However, it had a relatively higher overestimation in mGFR ≤ 30 mL/min/1.73 m 2 than most equations (18.5 mL/min/1.73m 2 , p < 0.001). Specifically, 64% of patients with mGFR ≤ 30 mL/min/1.73m 2 were incorrectly classified as a less severe CKD stage by CKD-EPI 2021. In Blacks, CKD-EPI 2021 underestimated eGFR by 17.9 mL/min/1.73 m 2 , which was higher than the alternate equations except for Royal Free Hospital ( p < 0.001). The novel race-neutral eGFR equation, CKD-EPI 2021, improves the GFR estimation overall but may not accurately capture true kidney function in cirrhosis, specifically at low GFR. There is an urgent need for a race-neutral equation in liver disease reflecting the complexity of kidney function physiology unique to cirrhosis, given implications for organ allocation and dual organ transplant.

Deceased Donor Renal Allograft Utility in Adult Single and Multi-organ Transplantation in the United States

Background

Deceased donor multiorgan transplants utilizing kidneys (MOTs) can improve outcomes for multiorgan recipients but reduces kidneys for chronic renal failure patients.

Methods

We reviewed the Organ Procurement and Transplantation Network database from 2015 through 2019, for adult deceased donor kidney transplants. Recipients were classified as kidney transplant alone (KTA) (n = 62,252) or MOTs pancreas-kidney, simultaneous pancreas-kidney (n = 3,976), liver-kidney, simultaneous liver-kidney (n = 3,212), heart-kidney, simultaneous heart-kidney (n = 808), and "other"-kidney, simultaneous "other" kidney (n = 73).

Results

Liver, heart, and lung-alone transplants were at least 7 times more frequent than their MOT correlate, whereas the inverse was true with pancreas transplantation with SPKs being by far the most common pancreas transplant type. On average, KTA recipients waited between 2.8 and 21.4 times longer than MOTs, with SPKs waiting the longest of the MOT types. Predialysis initiation transplants were less frequent in KTAs compared with MOTs. Use of high-quality grafts according to Kidney Donor Profile Index < 35% was frequent among MOTs, but uncommon in KTAs who had an Estimated Post Transplant Survival score (EPTS) of >20%. For recipients older than 65, SPKs and SOKs were rare, but SLKs and SHKs had a higher fraction of recipients than KTAs and were much more likely to use a Kidney Donor Profile Index <35% kidney. SPKs and KTAs with an EPTS ≤20% had the best kidney graft survival. KTAs with an EPTS ≤80% had better kidney graft survival than SLKs, SHKs, and SOKs.

Conclusions

This study highlights disparities in access to deceased donor kidneys for kidney-alone candidates versus MOTs and suggests opportunities to improve allocation.

Evaluation and Management of Kidney Dysfunction in Advanced Heart Failure: A Scientific Statement From the American Heart Association

Early identification of kidney dysfunction in patients with advanced heart failure is crucial for timely interventions. In addition to elevations in serum creatinine, kidney dysfunction encompasses inadequate maintenance of sodium and volume homeostasis, retention of uremic solutes, and disrupted endocrine functions. Hemodynamic derangements and maladaptive neurohormonal upregulations contribute to fluctuations in kidney indices and electrolytes that may recover with guideline-directed medical therapy. Quantifying the extent of underlying irreversible intrinsic kidney disease is crucial in predicting whether optimization of congestion and guideline-directed medical therapy can stabilize kidney function. This scientific statement focuses on clinical management of patients experiencing kidney dysfunction through the trajectory of advanced heart failure, with specific focus on (1) the conceptual framework for appropriate evaluation of kidney dysfunction within the context of clinical trajectories in advanced heart failure, including in the consideration of advanced heart failure therapies; (2) preoperative, perioperative, and postoperative approaches to evaluation and management of kidney disease for advanced surgical therapies (durable left ventricular assist device/heart transplantation) and kidney replacement therapies; and (3) the key concepts in palliative care and decision-making processes unique to individuals with concomitant advanced heart failure and kidney disease.

Racial and ethnic disparities in post-liver transplant outcomes for patients with acute-on-chronic liver failure: An analysis of the UNOS database

BACKGROUND

The incidence of hospitalisations related to acute-on-chronic liver failure (ACLF) is increasing. Liver transplantation (LT) remains the definitive treatment for the condition.

AIM

To evaluate the influence of race and ethnicity on LT outcomes in ACLF.

METHODS

We conducted a retrospective analysis utilising LT data from the United Network for Organ Sharing (UNOS) database. White patients served as the control group and patients of other races were compared at each ACLF grade. The primary outcomes assessed were graft failure and all-cause mortality.

RESULTS

Blacks exhibited a higher all-cause mortality (Grade 1: aHR 1.36, 95% CI 1.18-1.57, p < 0.001; Grade 2: aHR 1.27, 95% CI 1.08-1.48, p = 0.003; Grade 3: aHR 1.19, 95% CI 1.04-1.37, p = 0.01) and graft failure (Grade 1: aHR 2.05, 95% CI 1.58-2.67, p < 0.001; Grade 2: aHR 1.91, 95% CI 1.43-2.54, p < 0.001; Grade 3: aHR 1.50, 95% CI 1.15-1.96, p = 0.002). Hispanics experienced a lower all-cause mortality at grades 1 and 3 (Grade 1: aHR 0.83, 95% CI 0.72-0.96, p = 0.01; Grade 3: aHR 0.80, 95% CI 0.70-0.91, p < 0.001) and Asians with severe ACLF demonstrated decreased all-cause mortality (Grade 3: aHR 0.55, 95% CI 0.42-0.73, p < 0.001).

CONCLUSION

Black patients experienced the poorest outcomes and Hispanic and Asian patients demonstrated more favourable outcomes compared to Whites.

Simultaneous Liver and Kidney Transplantation in Patients Aged 70 y and Older: Proceed With Caution

BACKGROUND

The number of elderly patients aged 70 y and older with liver and kidney failure is increasing, mainly because of increasing prevalence of metabolic dysfunction-associated steatohepatitis. At present, limited data are available on the outcomes of elderly patients who fit the criteria for dual organ transplantation since the implementation of the simultaneous liver and kidney (SLK) allocation policy.

METHODS

We performed a retrospective analysis of the Organ Procurement and Transplantation Network database of adults aged 18 y and older undergoing SLK and kidney transplantation only from August 11, 2017, to December 31, 2022. We examined patient and graft survivals and compared the outcomes of the recipients aged 70 y and older undergoing SLK transplantation to those who received kidney transplant alone and kidney after liver transplant.

RESULTS

During the study period, there has been a significant rise in the number of patients aged 70 y and older undergoing SLK transplantation, with 6 patients undergoing SLK transplantation in 2017 and 63 in 2021. Patients aged 70 y and older had significantly lower survival with 82.9% at 1 y and 66.5% at 3 y compared with 89.3% and 78.8% in the 50-69 y age group and 93.2% and 88.6% in the 18-49 y age group, respectively. Overall, kidney allograft survival was significantly lower in the 70 y and older group, with 80.9% at 1 y and 66.4% at 3 y compared with 91.1% and 75.5%, respectively, in those undergoing kidney transplant alone. There was no difference in kidney allograft survival in those undergoing SLK and kidney after liver transplantation.

CONCLUSIONS

Although the outcomes are inferior in recipients of SLK transplant aged 70 y and older, chronologic age should not preclude them from undergoing transplantation. Kidney transplantation after liver transplantation could be considered to avoid futile transplants.

Improved outcomes of kidney after liver transplantation after the implementation of the safety net policy

The number of kidney after liver transplants (KALT) increased after the implementation of the United Network of Organ Sharing (UNOS) safety net policy, but the effects of the policy on KALT outcomes remain unknown. Using the UNOS database, we identified KALT between 60 and 365 days from liver transplant from January 1, 2010, to December 31, 2020. The main outcome was 1- and 3-year patient, liver, and kidney graft survival. Secondary outcomes included 6-month and 1-year acute rejection (AR) of liver and kidney, and 1-year kidney allograft function. Of the 256 KALT, 90 were pre-policy and 166 post-policy. Compared to pre-policy, post-policy 1- and 3-year liver graft survival was higher (54% and 54% vs. 86% and 81%, respectively, p <0.001), while 1- and 3-year kidney graft survival (99% and 75% vs. 92% and 79%, respectively, p =0.19), and 1- and 3-year patient survival (99% and 99% vs. 95% and 89%, respectively, p =0.11) were not significantly different. Subgroup analysis revealed similar trends in patients with and without renal failure at liver transplant. Liver AR at 6 months was lower post-policy (6.3% vs. 18.3%, p =0.006) but was similar (10.5% vs. 13%, p =0.63) at 1 year. Kidney AR was unchanged post-policy at 6 months and 1 year. Creatinine at 1 year did not differ post-policy versus pre-policy (1.4 vs. 1.3 mg/dL, p =0.07) despite a higher proportion of deceased donors, higher Kidney Donor Profile Index, and longer kidney cold ischemia time post-policy ( p <0.05 for all). This 3-year follow-up after the 2017 UNOS policy revision demonstrated that the safety net implementation has resulted in improved liver outcomes for patients who underwent KALT with no increased AR of the liver or the kidney allografts.

Novel indications for referral and care for simultaneous liver kidney transplant recipients

PURPOSE OF REVIEW

Kidney dysfunction is challenging in liver transplant candidates to determine whether it is reversible or not. This review focuses on the pertinent data on how to best approach liver transplant candidates with kidney dysfunction in the current era after implementing the simultaneous liver kidney (SLK) allocation policy and safety net.

RECENT FINDINGS

The implementation of the SLK policy inverted the steady rise in SLK transplants and improved the utilization of high-quality kidneys. Access to kidney transplantation following liver transplant alone (LTA) increased with favorable outcomes. Estimating GFR in liver transplant candidates remains challenging, and innovative methods are needed. SLK provided superior patient and graft survival compared to LTA only for patients with advanced CKD and dialysis at least 3 months. SLK can provide immunological protection against kidney rejection in highly sensitized candidates. Post-SLK transplant care is complex, with an increased risk of complications and hospitalization.

SUMMARY

The SLK policy improved kidney access and utilization. Transplant centers are encouraged, under the safety net, to reserve SLK for liver transplant candidates with advanced CKD or dialysis at least 3 months while allowing lower thresholds for highly sensitized patients. Herein, we propose a practical approach to liver transplant candidates with kidney dysfunction.

Current status of simultaneous liver-kidney transplantation

Simultaneous liver-kidney transplantation (SLK) is a feasible option for patients with end-stage liver disease and concomitant renal dysfunction or end-stage renal disease. SLK has gained significant attention primarily due to multiple alterations in the allocation criteria over the past two decades. This review aims to summarize the most recent updates and outcomes of the SLK allocation policy, comparing SLK outcomes with those of liver transplantation alone and exploring the implications of donation after cardiac death in SLK procedures.

Differential Impact of the UNOS Simultaneous Liver-kidney Transplant Policy Change Among Patients With Sustained Acute Kidney Injury

BACKGROUND

Simultaneous liver-kidney transplant (SLK) allocation policy in the United States was revised in August 2017, reducing access for liver transplant candidates with sustained acute kidney injury (sAKI) and potentially adversely impacting vulnerable populations whose true renal function is overestimated by commonly used estimation equations.

METHODS

We examined national transplant registry data containing information for all liver transplant recipients from June 2013 to December 2021 to assess the impact of this policy change using instrumental variable estimation based on date of listing.

RESULTS

Posttransplant survival was compared for propensity-matched patients with sAKI who were only eligible for liver transplant alone (LTA_post; n = 638) after the policy change but would have been SLK-eligible before August 2017, with similar patients who were previously able to receive an SLK (SLK; n = 319). Overall posttransplant patient survival was similar at 3 y (81% versus 80%; P = 0.9). However, receiving an SLK versus LTA increased survival among African Americans (87% versus 61% at 3 y; P = 0.029). A trend toward survival benefit from SLK versus LTA, especially later in the follow-up period, was observed in recipients ≥ age 60 (3-y survival: 84% versus 76%; P = 0.2) and women (86% versus 80%; P = 0.2).

CONCLUSIONS

The 2017 United Network for Organ Sharing SLK Allocation Policy was associated with reduced survival of African Americans with end-stage liver disease and sAKI and, potentially, older patients and women. Our study suggested the use of race-neutral estimation of renal function would ameliorate racial disparities in the SLK arena; however, further studies are needed to reduce disparity in posttransplant outcomes among patients with liver and kidney failure.

Differential in Kidney Graft Years on the Basis of Solitary Kidney, Simultaneous Liver-Kidney, and Kidney-after-Liver Transplants

BACKGROUND

The number of simultaneous liver-kidney (SLK) transplants has significantly increased in the United States. There has also been an increase in kidney-after-liver transplants associated with 2017 policy revisions aimed to fairly allocate kidneys after livers. SLK and kidney-after-liver candidates are prioritized in allocation policy for kidney offers ahead of kidney-alone candidates.

METHODS

We compared kidney graft outcomes of kidney-alone transplant recipients with SLK and kidney-after-liver transplants using paired kidney models to mitigate differences among donor risk factors. We evaluated recipient characteristics between transplant types and calculated differential graft years using restricted mean survival estimates.

RESULTS

We evaluated 3053 paired donors to kidney-alone and SLK recipients and 516 paired donors to kidney-alone and kidney-after-liver recipients from August 2017 to August 2022. Kidney-alone recipients were younger, more likely on dialysis, and Black race. One-year and 3-year post-transplant kidney graft survival for kidney-alone recipients was 94% and 86% versus SLK recipients 89% and 80%, respectively, P < 0.001. One-year and 3-year kidney graft survival for kidney-alone recipients was 94% and 84% versus kidney-after-liver recipients 93% and 87%, respectively, P = 0.53. The additional kidney graft years for kidney-alone versus SLK transplants was 21 graft years/100 transplants (SEM=5.0) within 4 years post-transplantation, with no significant difference between kidney-after-liver and kidney-alone transplants.

CONCLUSIONS

Over a 5-year period in the United States, SLK transplantation was associated with significantly lower kidney graft survival compared with paired kidney-alone transplants. Most differences in graft survival between SLK and kidney-alone transplants occurred within the first year post-transplantation. By contrast, kidney-after-liver transplants had comparable graft survival with paired kidney-alone transplants.

The Effect of New Acuity Circle Policy on Simultaneous Liver and Kidney Transplantation in the United States

Background

New deceased donor liver allocation policy using an acuity circle (AC)-based model was implemented on February 4th, 2020. The effect of AC policy on simultaneous liver-kidney transplantation (SLKT) remains unknown. The aim of this study was to assess the effect of AC policy on SLKT waitlist mortality, transplant probability, and post-transplant outcomes.

Methods

Using the United Network for Organ Sharing database, 4908 adult SLKT candidates during two study periods, pre-AC (Aug-2017 to Feb-2020, N = 2770) and post-AC (Feb-2020 to Dec-2021, N = 2138) were analyzed. Outcomes included 90-day waitlist mortality, transplant probability, and post-transplant patient and graft survival.

Results

Compared to pre-AC period, SLKT recipients during post-AC period had higher median model for end-stage liver disease (MELD) score (24 vs 23, P < 0.001), and less percentage of MELD exception (4.6% vs 7.7%, P = 0.001). The 90-day waitlist mortality was same, but the probability of SLKT increased in post-AC period (P < 0.001). Post-AC period also saw increased utilization of donation after cardiac death organs (11% vs 6.4%, P < 0.001) and decreased rates of transplantation among Black candidates (7.9% vs 13%). After risk adjustment, post-AC period was not associated with any significant difference in 90-day waitlist mortality (sub-distribution hazard ratio [sHR] 0.80; 95% CI 0.56-1.16, P = 0.24), and a higher 90-day probability of SLKT (sHR 1.68; 95% CI 1.41-1.99, P < 0.001). During post-transplant period, one-year patient survival, liver and kidney graft survival were comparable between two study periods.

Conclusions

The AC liver allocation policy was associated with increased transplant probability of adult SLKT candidates without decreasing waitlist mortality, post-transplant patient survival, or liver and kidney graft survival.

One size does not fit all: Differential benefits of simultaneous liver-kidney transplantation by eligibility criteria

Standard eligibility criteria for simultaneous liver-kidney transplantation (SLK) are in place in the United States. We hypothesize that the benefit associated with SLK over liver transplant alone differs by patient, depending on the specific SLK criteria met. We analyzed a retrospective US cohort of 5446 adult liver transplant or SLK recipients between January 1, 2015, and December 31, 2018, who are potentially qualified for SLK. Exposure was a receipt of SLK. We tested effect modification by the specific SLK eligibility criteria met (end-stage kidney disease, acute kidney injury, chronic kidney disease, or unknown). The primary outcome was death within 1 year of a liver transplant. We used a modified Cox regression analysis containing an interaction term of SLK * time from transplant. Two hundred ten (9%) SLK recipients and 351 (11%) liver-alone recipients died in 1 year. In the overall population, SLK was associated with a mortality benefit over liver transplant on the day of the transplant, without adjustment [HR: 0.59 (95% CI, 0.46-0.76)] and with adjustment [aHR: 0.50 (95% CI, 0.35-0.71)]. However, when SLK eligibility criteria were included, only in patients with end-stage kidney disease was SLK associated with a sustained survival benefit at day 0 [HR: 0.17 (0.08-0.35)] up to 288 (95% CI, 120-649) days post-transplant. Benefit within the first year post-transplant associated with SLK over liver-alone transplantation was only pronounced in patients with end-stage kidney disease but not present in patients meeting other criteria for SLK. A "strict SLK liberal Safety Net" strategy may warrant consideration at the national policy level.

Acute kidney injury in patients with acute-on-chronic liver failure: clinical significance and management

Acute-on-chronic-liver failure (ACLF) refers to a phenomenon in which patients with chronic liver disease develop multiple organ failure due to acute exacerbation of underlying liver disease. More than 10 definitions of ACLF are extant around the world, and there is lack of consensus on whether extrahepatic organ failure is a main component or a consequence of ACLF. Asian and European consortiums have their own definitions of ACLF. The Asian Pacific Association for the Study of the Liver ACLF Research Consortium does not consider kidney failure as a diagnostic criterion for ACLF. Meanwhile, the European Association for the Study of the Liver Chronic Liver Failure and the North American Consortium for the Study of End-stage Liver Disease do consider kidney failure as an important factor in diagnosing and assessing the severity of ACLF. When kidney failure occurs in ACLF patients, treatment varies depending on the presence and stage of acute kidney injury (AKI). In general, the diagnosis of AKI in cirrhotic patients is based on the International Club of Ascites criteria: an increase of 0.3 mg/dL or more within 48 hours or a serum creatinine increase of 50% or more within one week. This study underscores the importance of kidney failure or AKI in patients with ACLF by reviewing its pathophysiology, prevention methods, and treatment approaches.

Pros and Cons of the Safety Net Rule for Prioritization of Liver Transplant Recipients Who Receive Liver Alone Transplant but Develop End-Stage Renal Disease

The number of patients presenting with cirrhosis with kidney injury and the potential need for SLKT is increasing. In 2017, standardized criteria were implemented to identify candidates for SLKT as well as criteria for prioritizing LTA recipients for kidney transplant if they developed kidney failure, which is referred to as the 'safety net rule.' Goal of the safety net rule is to provide a pathway that provides increased priority to LTA recipients with renal failure who may have previously undergone SLKT. This article reviews the pros and cons of the safety net rule for liver transplant recipients who develop ESRD.

Kidney Allocation Policy: Past, Present, and Future

Despite an increase in the number of kidney transplants performed annually, there remain more than 90,000 individuals awaiting transplantation in the United States. As kidney transplantation has evolved, so has kidney allocation policies. The Kidney Allocation System, which was introduced in 2014, made significant strides to improve utility and equity, but regional and geographic disparities remain. Further modifications eliminating donor service areas have been introduced. Moving forward, systems involving continuous distribution and artificial intelligence may provide further advancement toward an ideal allocation system.

Kidney utilization and outcomes of liver transplant recipients who were listed for kidney after liver transplant after the implementation of safety net policy

In 2017, United Network for Organ Sharing (UNOS) established the safety net policy with set criteria for offering kidney transplantation (KT) for patients who developed end-stage renal disease between 60 and 365 days after liver transplant (LT). We provide an update on the impact of the policy. We analyzed UNOS data of liver recipients transplanted between 1987 and 2020 who developed acute kidney injury requiring dialysis within 60 days before or after LT and subsequently listed for KT. We identified 407 patients who were listed for kidney after LT before policy and 248 patients after policy. Median waiting time to KT was shorter after policy (324 days vs. 2827 days). There was a higher proportion of candidates who were listed for subsequent KT within 1-year after policy (94.8% vs. 63.6%). KT rate was also higher after policy (87.7 vs. 30.7 per 100 patient-years at risk). Most importantly, we started to observe a net negative kidney utilization in end-stage liver disease setting (i.e., summation of simultaneous liver kidney and kidney after liver transplant in the first-year after LT has decreased from 1086 to 876 transplants in 2019). Such findings are consistent with a more efficient system and more appropriate allocation of organs.