Predicting renal recovery after liver transplant with severe pretransplant subacute kidney injury: The impact of warm ischemia time

Rosiglitazone attenuates Acute Kidney Injury from hepatic ischemia-reperfusion in mice by inhibiting arachidonic acid metabolism through the PPAR-γ/NF-κB pathway

BACKGROUND

Acute Kidney Injury (AKI), a prevalent complication of Liver Transplantation (LT) that occurs during the perioperative period has been established to profoundly impact the prognosis of transplant recipients. This study aimed to investigate the mechanism of the hepatic IRI-induced AKI and to identify potential therapeutic targets for treating this condition and improving the prognosis of LT patients.

METHODS

An integrated transcriptomics and proteomics approach was employed to investigate transcriptional and proteomic alterations in hepatic IRI-induced AKI and the hypoxia-reoxygenation (H/R) model using TCMK-1 cells and the hepatic IRI-induced AKI mouse model using male C57BL/6 J mice were employed to elucidate the underlying mechanisms. Hematoxylin-eosin staining, reverse transcription quantitative polymerase chain reaction, enzyme-linked immunosorbent assay and Western blot were used to assess the effect of Rosiglitazone (RGZ) on hepatic IRI-induced AKI in vitro and in vivo.

RESULTS

According to the results, 322 genes and 128 proteins were differentially expressed between the sham and AKI groups. Furthermore, Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomics (KEGG) pathway analyses revealed significant enrichment in pathways related to amino acid and lipid metabolism. Additionally, the Protein-Protein Interaction (PPI) network analysis of the kidney tissues obtained from a hepatic IRI-induced AKI mouse model highlighted arachidonic acid metabolism as the most prominent pathway. Animal and cellular analyses further revealed that RGZ, a PPAR-γ agonist, could inhibit the expression of the PPAR-γ/NF-κB signaling pathway-associated proteins in in vitro and in vivo.

CONCLUSIONS

These findings collectively suggest that RGZ ameliorates hepatic IRI-induced AKI via PPAR-γ/NF-κB signaling pathway modulation, highlighting PPAR-γ as a crucial therapeutic target for AKI prevention post-LT.

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.

Acute Kidney Injury in Liver Cirrhosis

Acute kidney injury (AKI) is common in cirrhotic patients affecting almost 20% of these patients. While multiple etiologies can lead to AKI, pre-renal azotemia seems to be the most common cause of AKI. Irrespective of the cause, AKI is associated with worse survival with the poorest outcomes observed in those with hepatorenal syndrome (HRS) and acute tubular necrosis (ATN). In recent years, new definitions, and classifications of AKI in cirrhosis have emerged. More knowledge has also become available regarding the benefits and drawbacks of albumin and terlipressin use in these patients. Diagnostic tools such as urinary biomarkers and point-of-care ultrasound (POCUS) became available and they will be used in the near future to differentiate between different causes of AKI and direct management of AKI in these patients. In this update, we will review these new classifications, treatment recommendations, and diagnostic tools for AKI in cirrhotic patients.

Center variations in patient selection for simultaneous heart-kidney transplantation

There are no established regulations governing patient selection for simultaneous heart-kidney (SHK) transplantation, creating the potential for significant center-level variations in clinical practice.

METHODS

Using the United Network for Organ Sharing (UNOS) Standard Transplant Analysis and Research (STAR) file, we examined practice trends and variations in patient selection for SHK at the center level between January 1, 2004 and March 31, 2019.

RESULTS

Overall, SHK is becoming more common with most centers performing heart transplants also performing SHK. Among patients who underwent heart transplant who were receiving dialysis, the rate of SHK varied from 22% to 86% at the center level. Among patients not on dialysis, the median estimated glomerular filtration rate (eGFR) of patients receiving SHK varied between 19 and 59 mL/min/1.73 m² . When adjusting for other factors, the odds of SHK varied 57-fold between the highest and lowest SHK performing centers.

CONCLUSION

Variation in SHK at the center level suggests the need for national guidelines around the selection of patients for SHK.

Pediatric third liver transplantation-A single-center experience

BACKGROUND

Pediatric retransplantation is an accepted practice for graft failure and complications in Australasia. As 15% of children require a third transplant, this is a growing cohort with limited data in the literature.

METHODS

We review nine patients from the commencement of our transplantation program in 1986 up to 2020 assessing demographics, prognosis, and outcome measures.

RESULTS

Third transplant patient survival was comparative to first and second transplant patient survival at 5 years. All deaths were within the post-operative period and secondary to sepsis. Operative times and transfusion volumes were increased at third transplant (1.8 and 4.5 times compared to first transplant, respectively). Learning difficulties and psychological disturbances were prevalent (83% and 66.6%, respectively).

CONCLUSIONS

While recent mortality outcomes appear comparable to undergoing a second liver transplant, third transplant operations were more complex. Neurological impairment and psychological disturbance appear to be prevalent and need to be considered in pre-transplant counseling.

Conversion from Standard-Release Tacrolimus to MeltDose® Tacrolimus (LCPT) Improves Renal Function after Liver Transplantation

Renal impairment is a typical side effect of tacrolimus (Tac) treatment in liver transplant (LT) recipients. One strategy to avoid renal dysfunction is to increase the concentration/dose (C/D) ratio by improving drug bioavailability. LT recipients converted from standard-release Tac to MeltDose^® Tac (LCPT), a novel technological formulation, were able to reduce the required Tac dose due to higher bioavailability. Hence, we hypothesize that such a conversion increases the C/D ratio, resulting in a preservation of renal function. In the intervention group, patients were switched from standard-release Tac to LCPT. Clinical data were collected for 12 months after conversion. Patients maintained on standard-release Tac were enrolled as a control group. Twelve months after conversion to LCPT, median C/D ratio had increased significantly by 50% (p < 0.001), with the first significant increase seen 3 months after conversion (p = 0.008). In contrast, C/D ratio in the control group was unchanged after 12 months (1.75 vs. 1.76; p = 0.847). Estimated glomerular filtration rate (eGFR) had already significantly deteriorated in the control group at 9 months (65.6 vs. 70.6 mL/min/1.73 m² at study onset; p = 0.006). Notably, patients converted to LCPT already had significant recovery of mean eGFR 6 months after conversion (67.5 vs. 65.3 mL/min/1.73 m² at study onset; p = 0.029). In summary, conversion of LT recipients to LCPT increased C/D ratio associated with renal function improvement.

Acute kidney injury in hospitalized children: consequences and outcomes

Over the past decade, the nephrology and critical care communities have adopted a consensus approach to diagnosing acute kidney injury (AKI) and, as a result, we have seen transformative changes in our understanding of pediatric AKI epidemiology. The data regarding outcomes among neonates and children who develop AKI have become far more robust and AKI has been clearly linked with an increased need for mechanical ventilation, longer inpatient stays, and higher mortality. Though AKI was historically thought to be self-limited, we now know that renal recovery is far from universal, particularly when AKI is severe; the absence of recovery from AKI also carries longitudinal prognostic implications. AKI survivors, especially those without full recovery, are at risk for chronic renal sequelae including proteinuria, hypertension, and chronic kidney disease. This review comprehensively describes AKI-related outcomes across the entire pediatric age spectrum, using the most rigorous studies to identify the independent effects of AKI events.

Early detection of acute kidney injury in the perioperative period of liver transplant with neutrophil gelatinase-associated lipocalin

Background

Acute kidney injury (AKI) is a common complication in patients undergoing liver transplant (LT) and is associated with high morbidity and mortality. We aim to evaluate the pattern of urine and plasma neutrophil gelatinase-associated lipocalin (NGAL) elevation during the perioperative period of LT and to assess it as a prognostic marker for AKI progression, need for dialysis and mortality.

Methods

We assessed NGAL levels before induction of anesthesia, after portal reperfusion and at 6, 18, 24, and 48 h after surgery. Patients were monitored daily during the first week after LT.

Results

Of 100 enrolled patients undergoing liver transplant, 59 developed severe AKI based on the KDIGO serum creatinine (sCr) criterion; 34 were dialysed, and 21 died within 60 days after LT. Applying a cut-off value of 136 ng/ml, UNGAL values 6 h after surgery was a good predictor of AKI development within 7 days after surgery, having a positive predictive value (PPV) of 80% with an AUC of 0.76 (95% CI 0.67–0.86). PNGAL at 18 h after LT was also a good predictor of AKI in the first week, having a PPV of 81% and AUC of 0.74 (95% CI 0.60–0.88). Based on PNGAL and UNGAL cut-off criteria levels, time to AKI diagnosis was 28 and 23 h earlier than by sCr, respectively. The best times to assess the need for dialysis were 18 h after LT by PNGAL and 06 h after LT by UNGAL.

Conclusion

In conclusion, the plasma and urine NGAL elevation pattern in the perioperative period of the liver transplant can predict AKI diagnosis earlier. UNGAL was an early independent predictor of AKI development and need for dialysis. Further studies are needed to assess whether the clinical use of biomarkers can improve patient outcomes.

Trial registration

Registered at Clinical Trials (clinicaltrials.gov) in March 24th, 2014 by title “Acute Kidney Injury Biomarkers: Diagnosis and Application in Pre-operative Period of Liver Transplantation (AKIB)” and identifier NCT02095431, retrospectively registered.

Outcomes of Liver Transplantation in Patients on Renal Replacement Therapy: Considerations for Simultaneous Liver Kidney Transplantation Versus Safety Net

As the liver transplant (LT) waiting list continues to outpace organ availability, many patients require renal replacement therapy (RRT) before LT. It is unclear which patients will benefit from simultaneous liver kidney (SLK) transplant as opposed to awaiting a Safety Net kidney transplant (KT) post-LT.

Methods

In this study, a retrospective analysis of the United Network for Organ Sharing dataset was performed to identify risk factors associated with poor outcome for patients on RRT before LT who were listed for SLK and received either SLK vs LT alone (LTA).

Results

Between January 2003 and December 2016, 8971 adult LT recipients were on RRT at the time of LT. 5359 were listed for and received LTA (Group 1). Of 3612 patients listed for SLK, 3414 (38.1%) received SLK (Group 2) and 198 (2.2%) received LTA (Group 3). Overall, Group 3 had lower graft and patient survival post-LT when compared with Groups 1 and 2 (P < 0.001). Serum creatinine at 1 year post-LT and cumulative incidence for KT at 3 years post-LT were higher for Group 3 (P < 0.001). On multivariate analysis, pre-LT diabetes (P = 0.002), Model of End-Stage Liver Disease score (P = 0.01), and donor kidney donor profile index (P = 0.025) were significant in Group 2. Recipient age >60 (P < 0.001) and RRT pre-LT (>90 days; P = 0.001) were associated with lower patient survival in Group 3.

Conclusions

Among LT recipients on RRT before LT who were listed for SLK, RRT >90 days, and age >60 were associated with poor outcome following LTA. This suggests that programs should carefully weigh the decision to proceed with LTA vs waiting for SLK in this patient population. Future access to Safety Net KT will be an important consideration for these patients moving forward.

Role of serum levels of intraoperative brain natriuretic peptide for predicting acute kidney injury in living donor liver transplantation

Background

Patients with end-stage liver disease frequently experience acute kidney injury (AKI) after living donor liver transplantation (LDLT). Serum levels of brain natriuretic peptide (BNP) have increasingly been accepted as a predictor of AKI in clinical settings. This study investigated the predictive role of intraoperative BNP levels in the early development of AKI after LDLT.

Patients and methods

Adult patients (≥19 years old) who had undergone elective LDLT from January 2011 to December 2017 were classified into the non-AKI and AKI groups according to the Kidney Disease: Improving Global Outcomes criteria. Serum levels of BNP were measured three times in the preanhepatic, anhepatic, and neohepatic phases. Perioperative data in recipients and donors were analyzed retrospectively.

Results

Sixty-one patients (22.4%) suffered from AKI immediately after LDLT. Severity according to AKI stage was as follows: 28 patients in stage 1 (10.3%), 18 patients in stage 2 (6.6%), and 15 patients in stage 3 (5.5%). In the neohepatic phase, both BNP levels and proportions of patients with high BNP levels (≥100 pg/mL) were higher in the AKI group than in the non-AKI group. Only BNP levels in the non-AKI and AKI stage 1 groups significantly decreased from the preanhepatic phase to the neohepatic phase; those in AKI stages 2 and 3 groups did not. In particular, BNP levels of all AKI stage 3 patients increased to more than 100 pg/mL, and the proportion of patients with high levels also increased significantly through the surgical phases in the AKI stage 3 group. In multivariate analyses, BNP levels in the neohepatic phase were significantly associated with early development of AKI after LDLT, as well as the total amount of packed red blood cells in transfusions and total duration of graft ischemia.

Conclusions

Monitoring serum levels of BNP is useful for predicting the early development of AKI after LDLT.

Early Allograft Dysfunction Is Associated With Higher Risk of Renal Nonrecovery After Liver Transplantation

Supplemental digital content is available in the text.

Early allograft dysfunction (EAD) identifies allografts with marginal function soon after liver transplantation (LT) and is associated with poor LT outcomes. The impact of EAD on post-LT renal recovery, however, has not been studied. Data on 69 primary LT recipients (41 with and 28 without history of renal dysfunction) who received renal replacement therapy (RRT) for a median (range) of 9 (13-41) days before LT were retrospectively analyzed. Primary outcome was renal nonrecovery defined as RRT requirement 30 days from LT. Early allograft dysfunction developed in 21 (30%) patients, and 22 (32%) patients did not recover renal function. Early allograft dysfunction was more common in the renal nonrecovery group (50% vs 21%, P = 0.016). Multivariate logistic regression analysis demonstrated that EAD (odds ratio, 7.25; 95% confidence interval, 2.0-25.8; P = 0.002) and baseline serum creatinine (odds ratio, 3.37; 95% confidence interval, 1.4-8.1; P = 0.007) were independently associated with renal nonrecovery. History of renal dysfunction, duration of renal dysfunction, and duration of RRT were not related to renal recovery (P > 0.2 for all). Patients who had EAD and renal nonrecovery had the worst 1-, 3-, and 5-year patient survival, whereas those without EAD and recovered renal function had the best outcomes (P < 0.001). Post-LT EAD was independently associated with renal nonrecovery in LT recipients on RRT for a short duration before LT. Furthermore, EAD in the setting of renal nonrecovery resulted in the worst long-term survival. Measures to prevent EAD should be undertaken in LT recipients on RRT at time of LT.

New Developments in Hepatorenal Syndrome

Hepatorenal syndrome (HRS) continues to be one of the major complications of decompensated cirrhosis, leading to death in the absence of liver transplantation. Challenges in precisely evaluating renal function in the patient with cirrhosis remain because of the limitations of serum creatinine (Cr) alone in estimating glomerular filtration rate (GFR); current GFR estimating models appear to underestimate renal dysfunction. Newer models incorporating renal biomarkers, such as the Cr-Cystatin C GFR Equation for Cirrhosis appear to estimate measured GFR more accurately. A major change in the diagnostic criteria for HRS based on dynamic serial changes in serum Cr that regard HRS type 1 as a special form of acute kidney injury promises the possibility of earlier identification of renal dysfunction in patients with cirrhosis. The diagnostic criteria of HRS still include the exclusion of other causes of kidney injury. Renal biomarkers have been disappointing in assisting with the differentiation of HRS from prerenal azotemia and other kidney disorders. Serum metabolomic profiling may be a more powerful tool to assess renal dysfunction, although the practical clinical significance of this remains unclear. As a result of the difficulties of assessing renal function in cirrhosis and the varying HRS diagnostic criteria and the rigor with which they are applied, the precise incidence and prevalence of HRS is unknown, but it is likely that HRS occurs more commonly than expected. The pathophysiology of HRS is rooted firmly in the setting of progressive reduction in renal blood flow as a result of portal hypertension and splanchnic vasodilation. Progressive marked renal cortical ischemia in patients with cirrhosis parallels the evolution of diuretic-sensitive ascites to diuretic-refractory ascites and HRS, a recognized continuum of renal dysfunction in cirrhosis. Alterations in nitrous oxide production, both increased and decreased, may play a major role in the pathophysiology of this evolution. The inflammatory cascade, triggered by bacterial translocation and endotoxemia, increasingly recognized as important in the manifestation of acute-on-chronic liver failure, also may play a significant role in the pathophysiology of HRS. The mainstay of treatment remains vasopressor therapy with albumin in an attempt to reverse splanchnic vasodilation and improve renal blood flow. Several meta-analyses have confirmed the value of vasopressors, chiefly terlipressin and noradrenaline, in improving renal function and reversing HRS type 1. Other interventions such as renal replacement therapy, transjugular intrahepatic portosystemic shunt, and artificial liver support systems have a very limited role in improving outcomes in HRS. Liver transplantation remains the definitive treatment for HRS. The frequency of simultaneous liver-kidney transplantation has increased dramatically in the Model for End-stage Liver Disease era, with changes in organ allocation policies. This has resulted in a more urgent need to predict native kidney recovery from HRS after liver transplantation alone, to avoid unnecessary simultaneous liver-kidney transplantation.

Noteworthy Literature Published in 2016 for Abdominal Organ Transplantation Anesthesiologists

More than 3000 peer-reviewed publications on the topic of liver transplantation were published in 2016. The goal of this article is to provide a concise review of pertinent literature for anesthesiologists who participate in liver transplantation. The authors selected and presented 33 articles published in 2016 on the topics of MELD policy; cardiovascular, pulmonary, and renal issues; coagulation and transfusion; anesthetic agents; hemodynamic monitors; acute liver failure; and donor issues.