Impact of renal failure on liver transplantation survival

A report of a prospective randomized trial of extended-release tacrolimus versus immediate release tacrolimus after liver transplantation with anti-thymocyte induction in a steroid free protocol

PURPOSE

Our study hypothesis was that once daily dosing of extended-release tacrolimus (XRT) would be a safe and effective immunosuppression (IS) with the potential to decrease adverse events (AEs) associated with immediate release tacrolimus (IRT) after liver transplantation (LT).

METHODS

All patients receiving LT at our center received rabbit anti-thymocyte globulin (RATG) induction therapy. Eligible patients were randomized in a 1:1 fashion to receive either XRT or IRT. Antimicrobial prophylaxis was the same between arms, and both groups received an antimetabolite for the first 6 months following LT. Patients were then followed at pre-determined study intervals for the following year after LT. We administered the RAND-36SF survey to assess patient's health-related quality of life at pre-determined intervals. All analysis was performed with an intention to treat basis.

RESULTS

We screened 194 consecutive patients and enrolled 110. Our control and study arms were well matched. Transplant characteristics were similar between groups. At all timepoints, both arms had similar serum creatinine and estimated glomerular filtration rate (eGFR), calculated by MDRD6 equation, with post-transplant GFRs between 60 and 70 mL/min/1.73 m2 . Tacrolimus trough levels were similar between arms. The XRT arm had fewer AEs (166) and fewer serious AEs (70) compared to IRT (201 and 99, respectively). AEs most commonly were renal, infectious, or gastrointestinal in nature. While not statistically significant, XRT was held temporarily (25 vs. 35 cases) or discontinued (3 vs. 11 cases) less frequently than IRT and had fewer instances of rejection (7 vs. 12 cases).

CONCLUSION

This analysis showed that XRT is safe and effective as de novo maintenance IS in a steroid-free protocol with RATG.

AGA Clinical Practice Update on the Evaluation and Management of Acute Kidney Injury in Patients With Cirrhosis: Expert Review

DESCRIPTION

The purpose of this American Gastroenterological Association (AGA) Institute Clinical Practice Update is to review the available published evidence and expert advice regarding the clinical management of patients with suspected acute kidney injury in patients with cirrhosis.

METHODS

This article provides practical advice for the management of patients with cirrhosis and acute kidney injury based on the best available published evidence. This best practice document is not based on a formal systematic review. This expert review was commissioned and approved by the AGA Institute Clinical Practice Updates Committee and the AGA Governing Board to provide timely guidance on a topic of high clinical importance to the AGA membership and underwent internal peer review by the Clinical Practice Updates Committee and external peer review through the standard procedures of Clinical Gastroenterology & Hepatology. These Best Practice Advice (BPA) statements were drawn from a review of the published literature and from expert opinion. Since systematic reviews were not performed, these BPA statements do not carry formal ratings of the quality of evidence or strength of the presented considerations. BEST PRACTICE ADVICE 1: Acute kidney injury (AKI) should be diagnosed when the serum creatinine increases by ≥0.3 mg/dL within 48 hours or is ≥50% from baseline or when the urine output is reduced below 0.5 mL/kg/h for >6 hours. BEST PRACTICE ADVICE 2: Preventive measures against the development of AKI in cirrhosis include (1) avoidance of potentially nephrotoxic medications like nonsteroidal anti-inflammatory drugs (NSAIDs), (2) avoidance of excessive or unmonitored diuretics or nonselective beta-blockade, (3) avoidance of large-volume paracentesis without albumin replacement, and (4) counseling patients to avoid alcohol use. BEST PRACTICE ADVICE 3: (A) Investigation is directed to determining the cause of AKI, which can be due to hypovolemic causes (volume responsive, and the most common cause of AKI in patients with cirrhosis); acute tubular necrosis; hepatorenal syndrome with AKI (HRS-AKI) (a functional renal failure that persists despite volume repletion); HRS with acute kidney disease, a type of functional renal failure of <3 months- duration in which criteria for HRS-AKI are not met; or postrenal, which occurs only rarely. (B) The specific type of AKI should be identified through a careful history, physical examination, blood biochemistry, urine microscopic examination, urine chemistry (Na+ and urea) and selected urinary biomarkers, and renal ultrasound. BEST PRACTICE ADVICE 4: A rigorous search for infection is required in all patients with AKI. A diagnostic paracentesis should be carried out to evaluate for spontaneous bacterial peritonitis; blood and urine cultures and chest radiograph are also required. There is no role for routine prophylactic antibiotics in patients with AKI, but broad-spectrum antibiotics should be started whenever infection is strongly suspected. BEST PRACTICE ADVICE 5: When AKI is diagnosed, diuretics and nonselective beta-blockers should be held, NSAIDs discontinued, the precipitating cause of AKI treated, and fluid losses replaced, administering albumin 1 g/kg/d for 2 days if the serum creatinine shows doubling from baseline. Urine output, vital signs, and when indicated, echocardiography or CVP (if there is a pre-existing central line) should be used to monitor fluid status. BEST PRACTICE ADVICE 6: When the serum creatinine remains higher than twice the baseline value despite these measures, treatment of HRS-AKI should be initiated with albumin at a dose of 1 g/kg intravenously on day 1 followed by 20-40 g daily along with vasoactive agents (terlipressin; if terlipressin is not available, either a combination of octreotide and midodrine; or norepinephrine, depending on institutional preferences) and continued either until 24 hours following the return of the serum creatinine level to within ≤0.3 mg/dL of baseline for 2 consecutive days or for a total of 14 days of therapy. BEST PRACTICE ADVICE 7: Terlipressin should be initiated as a bolus dose of 1 mg every 4-6 hours (total 4-6 mg/d). The dose should be increased to a maximum of 2 mg every 4-6 hours (total 8-12 mg/d) if there is no reduction in serum creatinine at day 3 of therapy by at least 25% compared to the baseline value. Alternatively, clinicians can administer terlipressin by continuous intravenous infusion at a lower starting dose of 2 mg/d, which may reduce ischemic side effects and increase the dose gradually every 24-48 hours up to a maximum dose of 12 mg/d, or reversal of HRS. As per Food and Drug Administration restrictions, terlipressin should not be used in patients with a serum creatinine ≥5 mg/dL, or oxygen saturation of <90%. BEST PRACTICE ADVICE 8: Oral midodrine when used should be initiated at doses of 7.5 mg and titrated upward to 12.5 mg 3 times daily with octreotide (starting with 100 μg and titrating upward to 200 μg subcutaneously 3 times daily). BEST PRACTICE ADVICE 9: Norepinephrine should be used as a continuous intravenous infusion at a starting dose of 0.5 mg/h and the dose increased every 4 hours by 0.5 mg/h to a maximum of 3 mg/h with the goal of increasing the mean arterial pressure by ≥10 mm Hg and/or the urine output to >50 mL/h for at least 4 hours. BEST PRACTICE ADVICE 10: The risks of ischemic side effects of terlipressin and norepinephrine include angina and ischemia of fingers, skin, and intestine. These side effects may be lowered by starting at the lowest dose and gradually titrating upward. BEST PRACTICE ADVICE 11: Fluid status should be closely monitored because of the risk of pulmonary edema with excessive use of albumin. BEST PRACTICE ADVICE 12: Renal replacement therapy (RRT) may be used in the management of (A) AKI secondary to acute tubular necrosis; (B) HRS-AKI in potential candidates for liver transplantation (that is, RRT should not be used in patients with HRS-AKI who are not candidates for liver transplantation); and (C) AKI of uncertain etiology in which the need for RRT may be considered on an individual basis. BEST PRACTICE ADVICE 13: Transjugular intrahepatic portosystemic shunts should not be used as a specific treatment of HRS-AKI. BEST PRACTICE ADVICE 14: Liver transplantation is the most effective treatment for HRS-AKI. Pharmacotherapy for HRS-AKI before proceeding with liver transplantation may be associated with better post-liver transplantation outcomes. Selected patients with HRS-AKI may require simultaneous liver kidney transplantation based on updated Organ Procurement and Transplantation Network listing criteria.

Role of proenkephalin in the diagnosis of severe and subclinical acute kidney injury during the perioperative period of liver transplantation

In recent decades, clinical research on early biomarkers of renal injury has been frequent and intensive, with proenkephalin (PENK) being indicated as a promising filtration biomarker (BM). From a cohort of 57 patients, blood samples were collected preoperatively and 48 h after liver transplantation (LT). The following BMs were analyzed: PENK, cystatin-C (CYS-C), and serum creatinine (Scr). Diagnosis of AKI was based on the KDIGO criteria. Of the 57 patients undergoing LT, 50 (88%) developed acute kidney injury (AKI) and were categorized as follows: no-AKI/mild-AKI - 21 (36.8%) and severe-AKI 36 (63.2%). During the preoperative period, only PENK was significantly higher in patients with severe AKI, with an AUC of 0.69 (CI 0.54–0.83), a cutoff of 55.30 pmol/l, a sensitivity of 0.86, a specificity of 0.52, and an accuracy of 0.75. In addition, subclinical AKI was determined preoperatively in 32 patients. Forty-eight hours after LT, PENK maintained its performance in determining severe AKI, with an AUC of 0.83 (CI 0.72–0.94), a cutoff of 119.05 pmol/l, a sensitivity of 0.81, a specificity of 0.90, and an accuracy of 0.84. PENK detected AKI 48 h earlier than serum creatinine. In a multivariate linear regression analysis, PENK was an independent predictor of severe AKI. This small study suggests that the filtration biomarker PENK shows promise for detecting AKI in patients undergoing LT, revealing greater accuracy and an earlier rise in patients with severe AKI. The combination of kidney functional and filtration BMs may aid in the management and prevention of AKI progression.

[Kidney failure after liver transplantation]

One third of cirrhotic patients present impaired kidney function. It has multifactorial causes and has a harmful effect on patients' morbi-mortality before and after liver transplant. Kidney function does not improve in all patients after liver transplantation and liver-transplant recipients are at high risk of developing chronic kidney disease. Causes for renal dysfunction can be divided in three groups: preoperative, peroperative and postoperative factors. To date, there is no consensus for the modality of evaluation the risk for chronic kidney disease after liver transplantation, and for its prevention. In the present review, we describe the outcome of kidney function after liver transplantation, and the prognostic factors of chronic kidney disease to determine a risk stratification for each patient. Furthermore, we discuss therapeutic options to prevent kidney dysfunction in this setting, and highlight the indications of combined liver-kidney transplantation.

Kidney Failure after Liver Transplantation

One-third of patients with cirrhosis present kidney failure (AKI and CKD). It has multifactorial causes and a harmful effect on morbidity and mortality before and after liver transplantation. Kidney function does not improve in all patients after liver transplantation, and liver transplant recipients are at a high risk of developing chronic kidney disease. The causes of renal dysfunction can be divided into three groups: pre-operative, perioperative and post-operative factors. To date, there is no consensus on the modality to evaluate the risk of chronic kidney disease after liver transplantation, or for its prevention. In this narrative review, we describe the outcome of kidney function after liver transplantation, and the prognostic factors of chronic kidney disease in order to establish a risk categorization for each patient. Furthermore, we discuss therapeutic options to prevent kidney dysfunction in this context, and highlight the indications of combined liver–kidney transplantation.

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.

Liver Transplant Patients with High Levels of Preoperative Serum Ammonia Are at Increased Risk for Postoperative Acute Kidney Injury: A Retrospective Study

Acute kidney injury (AKI) is one of the most frequent postoperative complications after liver transplantation (LT). Increased serum ammonia levels due to the liver disease itself may affect postoperative renal function. This study aimed to compare the incidence of postoperative AKI according to preoperative serum ammonia levels in patients after LT. Medical records from 436 patients who underwent LT from January 2010 to February 2020 in a single university hospital were retrospectively reviewed. The patients were then categorized according to changes in plasma creatinine concentrations within 48 h of LT using the Acute Kidney Injury Network criteria. A preoperative serum ammonia level above 45 mg/dL was associated with postoperative AKI (p < 0.0001). Even in patients with a normal preoperative creatinine level, when the ammonia level was greater than 45 μg/dL, the incidence of postoperative AKI was significantly higher (p < 0.0001); the AKI stage was also higher in this group than in the group with preoperative ammonia levels less than or equal to 45 μg/dL (p < 0.0001). Based on the results of our research, an elevation in preoperative serum ammonia levels above 45 μg/dL is related to postoperative AKI after LT.

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.

Efficacy, safety, and pharmacokinetics of simeprevir, daclatasvir, and ribavirin in patients with recurrent hepatitis C virus genotype 1b infection after orthotopic liver transplantation: The Phase II SATURN study

BACKGROUND

Recurrent hepatitis C virus (HCV) infection following liver transplantation is associated with accelerated progression to graft failure and reduced patient survival.

METHODS

The Phase II, open-label SATURN study (NCT01938625) investigated the combination of simeprevir (SMV), daclatasvir (DCV), and ribavirin (RBV) administered for 24 weeks in 35 patients with recurrent HCV genotype (GT) 1b infection after orthotopic liver transplantation (OLT).

RESULTS

High rates of both on-treatment and sustained virologic response 12 weeks after end of treatment (SVR12) were achieved in patients who were either treatment-naïve or had failed post-OLT treatment with peginterferon and RBV. Overall, 91% of patients (32/35) achieved SVR12. The combination was generally well tolerated, with an adverse event profile consistent with that observed in previous clinical trials of SMV or DCV separately. Co-administration of SMV with cyclosporine resulted in significantly increased SMV plasma exposures, which was not the case with the co-administration of SMV with tacrolimus. Therefore, the concomitant use of SMV with cyclosporine is not recommended.

CONCLUSION

The interferon-free combination of SMV, DCV, and RBV administered for 24 weeks was shown to be effective and well tolerated in the treatment of post-OLT HCV GT1b-infected patients.

Impact of preoperative chronic renal failure on liver transplantation: a population-based cohort study

Purpose

The purpose of this study was to assess whether preoperative chronic renal failure (CRF) affects the rates of postoperative complications and survival after liver transplantation.

Methods

This population-based retrospective cohort study included 2,931 recipients of liver transplantation performed between 1998 and 2012, enrolled from the Taiwan National Health Insurance Research Database. Patients were divided into two groups, based on the presence or absence of preoperative CRF.

Results

The overall estimated survival rate of liver transplantation recipients (LTRs) with preoperative CRF was significantly lower than that of patients without preoperative CRF (P=0.0085). There was no significant difference between the groups in terms of duration of intensive care unit stay, total hospital stay, bacteremia, postoperative bleeding, and pneumonia during hospitalization. Long-term adverse effects, including cerebrovascular disease and coronary heart disease, were not different between patients with versus without CRF.

Conclusion

These findings suggest that LTRs with preoperative CRF have a higher rate of mortality.

Dexmedetomidine Pretreatment Attenuates Kidney Injury and Oxidative Stress during Orthotopic Autologous Liver Transplantation in Rats

This paper aims to explore whether pretreatment with dexmedetomidine (Dex) has antioxidative and renal protective effects during orthotopic autologous liver transplantation (OALT) and its impact on nuclear factor erythroid 2-related factor 2 (Nrf2) activation. Sprague-Dawley rats were randomized into groups that include sham-operated (group S), model (group M), low dose Dex (group D1), high dose Dex (group D2), atipamezole (a nonspecific α₂ receptor blocker) + high dose Dex (group B1), ARC239 (a specific α_2B/c receptor blocker) + high dose Dex (group B2), and BRL-44408 (a specific α_2A receptor blocker) + high dose Dex (group B3). Then histopathologic examination of the kidneys and measurement of renal function, the renal Nrf2 protein expression, and oxidants and antioxidants were performed 8 hours after OALT. We found that pretreatment with Dex activated Nrf2 in glomerular cells and upregulated antioxidants but reduced oxidants (all P < 0.01, group D2 versus group M). Atipamezole and BRL-44408, but not ARC239, reversed these protective effects. In conclusion, pretreatment with Dex activates Nrf2 through α_2A receptor, increases the antioxidant levels, and attenuates renal injury during OALT.

Comparison of RIFLE and AKIN criteria in the evaluation of the frequency of acute kidney injury in post-liver transplantation patients

BACKGROUND

Acute renal dysfunction is presented quite often after orthotopic liver transplantation (LT), with a reported incidence of 12-64%. The "RIFLE" criteria were introduced in 2004 for the definition of acute kidney injury (AKI) in critically ill patients, and a revised definition was proposed in 2007 by the Acute Kidney Injury Network (AKIN), introducing the AKIN criteria. The aim of this study was to record the incidence of AKI in patients after LT by both classifications and to evaluate their prognostic value on mortality.

METHODS

We retrospectively evaluated the records of patients with LT over 2 years (2011-2012) and recorded the incidence of AKI as defined by the RIFLE and AKIN criteria. Preoperative and admission severity of disease scores, duration of mechanical ventilation, intensive care unit length of stay, and 30- and 180-day survivals were also recorded.

RESULTS

Seventy-one patients were included, with an average age of 51.78 ± 10.3 years. The incidence of AKI according to the RIFLE criteria was 39.43% (Risk, 12.7%; Injury, 12.7%; Failure, 14.1%), whereas according to the AKIN criteria it was 52.1% (stage I, 22.5%; stage II, 7%; stage II 22.55%). AKI, regardless of the classification used, was related to the Model for End-Stage Liver Disease score, the volume of transfusions, the duration of mechanical ventilation, and survival. The presence of AKI was related to higher mortality, which rose proportionally with the severity of AKI as defined by the stages of either the RIFLE or the AKIN criteria.

CONCLUSIONS

AKI classifications according to the RIFLE and AKIN criteria are useful tools in the recognition and classification of the severity of renal dysfunction in patients after LT, because they are associated with higher mortality, which rises proportionally with the severity of renal disease.

Molecular Absorbent Recirculating System therapy (MARS®) in pediatric acute liver failure: a single center experience

BACKGROUND

Supportive care as a bridge to transplant or recovery remains challenging in children suffering from acute liver failure (ALF). We report our experience in children using the Molecular Absorbent Recirculating System (MARS(®)).

METHODS

Retrospective data from children receiving therapy using MARS(®) from October 2009 to October 2012 were included in this single-center retrospective study. Patient characteristics, clinical presentation and complications of ALF, clinical and biological data before and after each MARS(®) session, technical modalities and adverse events were recorded.

RESULTS

A total of six children underwent 17 MARS(®) sessions during the study period. Two adolescents were treated with the adult filter MARSFLUX(®) and four infants were treated with the MiniMARS(®) filter. The mean PEdiatric Logistic Dysfunction (PELOD) score at admission was 19 (range 11-33). All patients were mechanically ventilated, and four had acute kidney injury. The neurological course improved in one case, judged as stable in two cases and worsened in one case; data were unavailable in two cases. Mean serum ammonia levels decreased significantly following treatment with MARS(®) from an initial 89 ± 29 to 58 ± 35 mcmol/L (p = 0.02). No other significant biological improvement was observed. Hemodynamic status improved/remained unchanged in the adolescent group, but in the infants four of the seven sessions were poorly tolerated and two sessions were aborted. Three patients died, two were successfully transplanted and one recovered without transplantation.

CONCLUSION

In our experience, treatment with MARS(®) is associated with encouraging results in adolescents, but it needs modification for very sick infants to improve tolerance.

Twenty-year longitudinal follow-up after orthotopic liver transplantation: a single-center experience of 313 consecutive cases

With excellent short-term survival in liver transplantation (LT), we now focus on long-term outcome and report the first European single-center 20-year survival data. Three hundred thirty-seven LT were performed in 313 patients (09/88-12/92). Impact on long-term outcome was studied and a comparison to life expectancy of matched normal population was performed. A detailed analysis of 20-years follow-up concerning overweight (HBMI), hypertension (HTN), diabetes (HGL), hyperlipidemia (HLIP) and moderately or severely impaired renal function (MIRF, SIRF) is presented. Patient and graft survival at 1, 10, 20 years were 88.4%, 72.7%, 52.5% and 83.7%, 64.7% and 46.6%, respectively. Excluding 1-year mortality, survival in the elderly LT recipients was similar to normal population. Primary indication (p < 0.001), age (p < 0.001), gender (p = 0.017), impaired renal function at 6 months (p < 0.001) and retransplantation (p = 0.034) had significant impact on patient survival. Recurrent disease (21.3%), infection (20.6%) and de novo malignancy (19.9%) were the most common causes of death. Prevalence of HTN (57.3-85.2%, p < 0.001), MIRF (41.8-55.2%, p = 0.01) and HBMI (33.2-45%, p = 0.014) increased throughout follow-up, while prevalence of HLIP (78.0-47.6%, p < 0.001) declined. LT has conquered many barriers to achieve these outstanding long-term results. However, much work is needed to combat recurrent disease and side effects of immunosuppression (IS).

Calcineurin inhibitors in liver transplantation - still champions or threatened by serious competitors?

Current strategies for immunosuppression in liver transplant (LT) recipients include the design of protocols targeting a more individualized approach to reduce risk factors such as renal failure, cardiovascular complications and malignancies. Renal injury in LT recipients may be often multifactorial and is associated with increased risk of post-transplant morbidity and mortality. The quest for low toxicity immunosuppressive regimens has been challenging and resulted in CNI minimization protocols or CNI withdrawal and conversion to mycophenolate mofetil (MMF) and/or mammalian target of rapamycin inhibitor-based immunosuppressive regimens. Use of antibody induction to delay CNI administration may be an option in particular in immunocompromized, critically ill patients with high MELD scores. Protocols including MMF introduction and concomitant CNI minimization have the potential to recover renal function even in the medium and long term after LT. We review on hot topics in the prevention and management of acute and chronic renal injury in LT patients. For this purpose, we present and critically discuss results from immunosuppressive studies published in the current literature or presented at recent LT meetings.

Long-term outcome after liver transplantation

Liver transplantation is a life-saving therapy for patients with end-stage liver disease, acute liver failure, and liver tumors. Over the past 4 decades, improvements in surgical techniques, peritransplant intensive care, and immunosuppressive regimens have resulted in significant improvements in short-term survival. Focus has now shifted to addressing long-term complications and improving quality of life in liver recipients. These include adverse effects of immunosuppression; recurrence of the primary liver disease; and management of diabetes, hypertension, dyslipidemia, obesity, metabolic syndrome, cardiovascular disease, renal dysfunction, osteoporosis, and de novo malignancy. Issues such as posttransplant depression, employment, sexual function, fertility, and pregnancy must not be overlooked, as they have a direct impact on the liver recipient's quality of life. This review summarizes the latest data in long-term outcome after liver transplantation.

Strategies to prevent or reduce acute and chronic kidney injury in liver transplantation

Acute kidney injury (AKI) has a major impact on short- and long-term survival in liver transplant (LT) patients. There is no currently accepted uniform definition of AKI, which would facilitate standardization of the care of patients with AKI and to improve and enhance collaborative research efforts. New promising biomarkers such as neutrophil gelatinase-associated lipocalin or kidney injury molecule-1 have been developed for the prevention of delayed AKI treatment. Early dialysis has been shown to be beneficial in patients with AKI stage III according to the classification of the Acute Kidney Injury Network, whereas treatment with loop diuretics or dopamine is associated with worse outcome. The mainstay for the prevention of AKI seems to be avoidance of volume depletion and maintenance of a mean arterial pressure >65 mmHg. Although the aetiology of chronic kidney disease in transplant recipients may be multifactorial, calcineurin-inhibitor (CNI)-induced nephrotoxicity significantly contributes to the development of renal dysfunction over time after LT. The delayed introduction of CNI at minimal doses has shown to be safe and effective for the preservation of kidney function. Other strategies to overcome CNI nephrotoxicity include CNI minimization protocols or CNI withdrawal and conversion to mycophenolate mofetil or the mammalian target of rapamycin inhibitor-based immunosuppressive regimens. However, CNI avoidance may bear a higher rejection risk. Thus, more results from randomized-controlled studies are urgently warranted to determine which drug combinations are the most beneficial approaches for the potential introduction of CNI-free immunosuppressive regimens.

Role of biomaterials, therapeutic molecules and cells for hepatic tissue engineering

Current liver transplantation strategies face severe shortcomings owing to scarcity of donors, immunogenicity, prohibitive costs and poor survival rates. Due to the lengthy list of patients requiring transplant, high mortality rates are observed during the endless waiting period. Tissue engineering could be an alternative strategy to regenerate the damaged liver and improve the survival and quality of life of the patient. The development of an ideal scaffold for liver tissue engineering depends on the nature of the scaffold, its architecture and the presence of growth factors and recognition motifs. Biomimetic scaffolds can simulate the native extracellular matrix for the culture of hepatocytes to enable them to exhibit their functionality both in vitro and in vivo. This review highlights the physiology and pathophysiology of liver, the current treatment strategies, use of various scaffolds, incorporation of adhesion motifs, growth factors and stem cells that can stabilize and maintain hepatocyte cultures for a long period.

Kidney function and mortality post-liver transplant in the Model for End-Stage Liver Disease era

The Model for End-Stage Liver Disease (MELD) score incorporates serum creatinine and was introduced to facilitate allocation of orthotopic liver transplantation (LT). The objective is to determine the impact of MELD and kidney function on all-cause mortality. Among LTs performed in a tertiary referral hospital between 1995 and 2009, 419 cases were studied. Cox proportional hazards models were constructed to estimate the hazard ratios (HR) and 95% confidence intervals (CI) for death. Over mean follow-ups of 8.4 and 3.1 years during the pre-MELD and MELD era, 57 and 63 deaths were observed, respectively. Those transplanted during the MELD era had a higher likelihood of hepatorenal syndrome (8% vs 2%, P < 0.01), lower kidney function (median estimated glomerular filtration rate [eGFR] 77.8 vs 92.6 mL/ min/1.73 m², P < 0.01), and more pretransplantation renal replacement therapy (RRT) (5% vs 1%; P < 0.01). All-cause mortality risk was similar in the MELD vs the pre-MELD era (HR: 0.98, 95% CI: 0.58–1.65). The risk of death, however, was nearly 3-fold greater (95% CI: 1.14–6.60) among those requiring pre- transplant RRT. Similarly, eGFR < 60 mL/min/1.73 m² post-transplant was associated with a 2.5-fold higher mortality (95% CI: 1.48–4.11). The study suggests that MELD implementation had no impact on all-cause mortality post-LT. However, the need for pre-transplant RRT and post-transplant kidney dysfunction was associated with a more than 2-fold greater risk of subsequent death.

[Association between the use of blood components and the five-year mortality after liver transplant]

BACKGROUND AND OBJECTIVES

Liver transplant (LT) surgery is associated with significant bleeding in 20% of cases, and several authors have demonstrated the risks related to blood components. The objective of the present study was to evaluate the impact of using blood components during hospitalization in five-year survival of patients undergoing LT.

METHODS

One hundred and thirteen patients were evaluated retrospectively. Several variables, including the use of blood components intraoperatively and throughout hospitalization, were categorized and evaluated by univariate analysis using Fisher's test. A level of significance of 5% was adopted. Results with p < 0.2 underwent multivariate analysis using multinomial logistic regression.

RESULTS

Parenchymal diseases, preoperative renal dysfunction, and longer stay in hospital and ICU are associated with greater five-year mortality after LT (p < 0.05). Unlike the intraoperative use of blood components, the accumulated transfusion of packed red blood cell, frozen fresh plasma, and platelets during the entire hospitalization was associated with greater five-year mortality after liver transplantation (p < 0.01).

CONCLUSIONS

This study emphasizes the relationship between the use of blood components during hospitalization and increased mortality in five years after LT.

Basiliximab induction and delayed calcineurin inhibitor initiation in liver transplant recipients with renal insufficiency

BACKGROUND

Renal insufficiency (RI) is common after liver transplantation (LT) and may worsen due to calcineurin inhibitor (CNI) use. We compared LT outcomes using basiliximab induction and delayed CNI initiation to controls with a standard CNI regimen in patients with peri-LT RI.

METHODS

All adults transplanted January 2004 to December 2007 with peri-LT RI (hemodialysis or creatinine ≥1.5 within 1 week of LT) were included in a retrospective nonrandomized cohort. Outcomes including 30-day and 1-year patient and graft survival and renal function were compared between basiliximab and control groups.

RESULTS

Two hundred twenty-nine patients (102 basiliximab, 127 controls) were analyzed, mean age 54 years, 72% men, 54% with hepatitis C virus. Mean model for end-stage liver disease (28.2 vs. 20.0; P<0.001) and creatinine (1.9 vs. 1.6; P=0.001) were higher and more patients were on hemodialysis at LT (29% vs. 6%; P<0.001) in the basiliximab group. 30-day patient (99% vs. 97%; P=0.26) and graft survival (98% vs. 95%; P=0.17), 1-year patient (87% vs. 87%; P=0.89) and graft survival (86% vs. 82%; P=0.37), mean creatinine at 1-year (1.5 vs. 1.5 mg/dL; P=0.82), and treated acute rejection (6% vs. 6%; P=0.90) were similar between basiliximab and control groups, respectively. In multivariable logistic regression, basiliximab was not significantly associated with 30-day (odds ratio, 0.10; P=0.11) or 1-year (odds ratio, 0.97; P=0.94) survival, controlling for age, previous LT, model for end-stage liver disease, and hepatitis C virus.

CONCLUSIONS

Basiliximab induction resulted in 30-day and 1-year patient, graft and renal outcomes comparable with a control group receiving standard CNI-based immunosuppression. Antibody induction with delayed CNI should be further studied prospectively.

Postliver transplant acute renal injury and failure by the RIFLE criteria in patients with normal pretransplant serum creatinine concentrations: a matched study

BACKGROUND

Acute renal injury (ARI) and acute renal failure (ARF) are serious complications after liver transplantation (LT). Few studies apply the risk, injury, function, loss, and end-stage criteria on the patients who have normal preoperative renal function. The aims of this study were to identify the incidence, risk factors, and impact of ARI and ARF in this patient population.

METHODS

After institutional review board approval, adult LT patients who had preoperative serum creatinine less than or equal to 1.5mmol/L were reviewed. Postoperative ARI and ARF were determined by the risk, injury, function, loss, and end-stage criteria. Risk factors were determined by multivariable regression. Postoperative outcomes were compared among patients with or without ARI or ARF.

RESULTS

Among 334 patients included the study, 20.4% and 18.0% had ARI or ARF in the first week after LT, respectively. Then 118 ARI or ARF patients were matched with patients without post-LT renal injury by gender, creatinine, and body mass index. Multivariable analysis showed that increased requirement of red blood cell transfusion (odds ratio [OR] 2.7-8.8, P<0.05), vasopressors (OR 2.2, P=0.018), and pre-LT albumin less than or equal to 3.5 mg/dL (OR: 2.8, P=0.003) as risk factors for post-LT ARI or ARF. Both ARI and ARF were associated with longer hospital stay and higher reoperation rate. ARF, but not ARI, was associated with higher 30-day graft failure and mortality rates.

CONCLUSION

Post-LT ARI or ARF occurred frequently in patients with normal preoperative renal function and was associated with both preoperative and intraoperative risk factors. Although both post-LT ARI and ARF are associated with significant post-LT morbidity, the impact of ARF is greater.

The renal benefit of mycophenolate mofetil after liver transplantation

BACKGROUND

The risk and benefit of adding mycophenolate mofetil (MMF) to a standard immunosuppressive regimen at the time of liver transplantation (LT) is not well described.

METHODS

We performed a retrospective case-control analysis comparing one-yr outcomes of all LT recipients at our institution treated with post-operative tacrolimus (TAC), MMF, and steroids vs. TAC and steroids.

RESULTS

A total of 101 LT recipients (50:51 case:control) were analyzed. Despite more renal dysfunction at LT, the MMF + TAC group had similar serum creatinine (Cr) and glomerular filtration rate (GFR) as the TAC group one-yr post-LT. In this time period, Cr decreased (1.57-1.22 mg/dL, p = 0.04) and GFR increased (57.5-65.1 mL/min per 1.73 m(2), p = 0.05) in the MMF + TAC group, while Cr increased (1.11-1.35, p < 0.01) and GFR declined (73.5-60.1, p < 0.001) in the TAC group. These findings occurred without a difference in absolute rejection episodes, hospitalizations, infections, deaths, or time to above events (p > 0.05). Subgroup analysis of patients stratified by pre-transplant renal dysfunction (Cr ≥ 1.2 mg/dL) supported the previous. MMF was reasonably well tolerated with a low rate of discontinuation.

CONCLUSIONS

The use of adjunctive MMF immediately after LT may protect against calcineurin inhibitor nephrotoxicity, potentially without the need for dose reduction or increased risk of adverse events.

Neutrophil gelatinase--associated lipocalin predicts acute kidney injury in patients undergoing liver transplantation

Postoperative acute kidney injury (AKI) increases morbidity and mortality after liver transplantation (LT). Novel methods of assessing AKI including cystatin C (CyC) and neutrophil gelatinase-associated lipocalin (NGAL) have been identified as potential markers of AKI. We compare the ability of standard renal markers (serum creatinine [sCr], estimated glomerular filtration rate [eGFR] and intensive therapy unit organ failure scores with CyC and NGAL to predict AKI within the first 48 hours after LT. 95 patients (median age 50 [interquartile range = 41-59], 60% male) underwent LT (25% with acute liver failure). AKI was defined according to the Acute Kidney Injury Network criteria. Severe AKI was classified as ≥stage 2. NGAL (urine [u] and plasma [p]) and CyC concentrations taken immediately after transplantation on admission to the Liver Intensive Care Unit were compared with standard markers of renal function. Predictive ability was assessed using the area under the curve generated by receiver operator characteristic analysis (AUROC) and logistic regression. Day 0 sCr, uNGAL, pNGAL, CyC, and eGFR predicted AKI as did SOFA (Sequential Organ Failure Assessment) and APACHE II (Acute Physiology and Chronic Health Evaluation II) scores. APACHE II and pNGAL were the most powerful predictors of severe AKI (APACHE II AUROC = 0.87 [0.77-0.97], P < 0.001; pNGAL AUROC = 0.87 [0.77-0.92], P < 0.001). Using multivariate logistic regression, APACHE II (odds ratio 1.64/point [95% confidence interval = 1.22-2.21, P = 0.001] and pNGAL [odds ratio = 1.01/ng/mL [95% confidence interval = 1.00-1.02], P = 0.002) retained independent significance. A "renal risk score" using APACHE II > 13 and pNGAL > 258 ng/mL was calculated with a score of ≥1 having a 100% sensitivity and 76% specificity for severe AKI. In conclusion, a combination of NGAL and APACHE II predicts AKI with high sensitivity and specificity after LT.

High prevalence of renal dysfunction in children after liver transplantation: non-invasive diagnosis using a cystatin C-based equation

BACKGROUND

Chronic kidney disease (CKD) has been increasingly shown to be a negative prognostic factor after liver transplantation (Ltx). Creatinine-based glomerular filtration rate (GFR) formulas are notoriously insensitive. In children, non-invasive determination of GFR by measurement of serum cystatin C is feasible and repeatedly correlated to the gold standards of GFR measurements. The aim of our study was to determine GFR using cystatin C (GFR(cys)) in comparison with conventional calculated creatinine clearance (GFR(crea)) in the long-term follow-up after paediatric liver transplantation (pLtx) in a large number of patients.

METHODS

GFR of 168 children following liver transplantation was determined using cystatin C (GFR(cys)) and the Schwartz formula (GFR(crea)). In order to evaluate risk factors for CKD, a logistic regression analysis was performed. A multivariate model was applied to assess the impact of immunosuppressive treatment.

RESULTS

The mean follow-up after transplantation was 7.8 (0.44-15.72) years. Due to a high overestimation of GFR as demonstrated in a Bland-Altman plot, only three patients with CKD stages 2-3 were detected with GFR(crea) compared with 34 with GFR(cys) (P < 0.001). Thus, prevalence of CKD with GFR((cys)) < 90 mL/min/1.73 m2; was 30.4%, 7.6% and 27% in patients with 5, 10 and > 10 years of follow-up, respectively. Patients on cyclosporine had a significantly lower GFR than patients on tacrolimus. Logistic regression analysis did not show any significant risk factor for the development of CKD.

CONCLUSIONS

The cystatin C equation is a non-invasive and sensitive diagnostic tool to detect renal dysfunction in children after Ltx at an early stage. The choice of first-line calcineurin inhibitor has an important impact on the development of CKD.

Role of magnetic resonance cholangiography in biliary complications of orthotopic liver transplantation

PURPOSE

The aim of this study was to evaluate the role of magnetic resonance cholangiography (MRC) in the detection of biliary complications following orthotopic liver transplantation (OLT).

MATERIALS AND METHODS

Seventy-eight transplant patients with clinically suspected biliary complications were evaluated with 1.5-T magnetic resonance imaging (MRI) using a surface coil. All patients were imaged with the following sequences: axial T1-weighted and axial and coronal T2-weighted, 2D spin echo (SE) breath-hold radial cholangiography, and coronal 3D single-shot turbo spin echo (SS-TSE) with respiratory triggering. Patients with negative MRI underwent clinical and sonographic followup. When biliary complications were present, diagnostic confirmation was obtained by endoscopic retrograde cholangiopancreatography (ERCP) (n=13), percutaneous transhepatic cholangiography (PTC) (n=20), ultrasonography (n=10) or computed tomography (CT) (n=2). In 11 cases, surgical confirmation was also obtained.

RESULTS

MRC detected biliary complications in 44/78 patients, in particular, 42 biliary strictures (37 anastomotic and five intrahepatic), 40 of which were confirmed by other imaging modalities. In 25/37 cases of anastomotic stricture, preanastomotic dilatation of the biliary tract was also demonstrated. Other MRC-detected biliary complications were biliary sludge (n=4), biloma (n=5), and biliary stones (n=3). In four cases, PTC revealed biliary complications that had not been detected with MRC (false negative results). In two cases, MRC showed unconfirmed strictures of the intrahepatic ducts and biliodigestive anastomosis (false positive results). The sensitivity, specificity, positive (PPV) and negative (NPV) predictive values and diagnostic accuracy of MRC were 93.5%, 94.4%, 96.7%, 89.5% and 93.9%, respectively.

CONCLUSIONS

Our results confirm that MRC is a reliable technique for depicting biliary anastomoses and detecting biliary complications after OLT. The high diagnostic accuracy of MRC indicates that this examination should be routinely employed in all OLT patients with clinically suspected biliary complications.

Outcome of liver transplantation for drug-induced acute liver failure in the United States: analysis of the United Network for Organ Sharing database

Acute liver failure (ALF) is an uncommon but potentially lethal drug-related adverse effect that often leads to liver transplantation (LT) or death. A retrospective cohort study was performed with the United Network for Organ Sharing Standard Transplant Analysis and Research files. Recipients who underwent LT for drug-induced acute liver failure (DIALF) from 1987 through 2006 were analyzed. A total of 661 patients transplanted for DIALF were included in the analysis. The 4 leading implicated drug groups were acetaminophen (n = 265; 40%), antituberculosis drugs (n = 50; 8%), antiepileptics (n = 46; 7%), and antibiotics (n = 39; 6%). One-year estimated survival probabilities were 76%, 82%, 52%, 82%, and 79% for acetaminophen, antituberculosis drugs, antiepileptics, antibiotics, and others, respectively. The lower rate of survival among those exposed to antiepileptics was observed mainly in children. Of the 22 patients less than 18 years old who had ALF due to antiepileptics, 73% died within the first year. The difference in overall survival between acetaminophen-related and non-acetaminophen-related ALF was not statistically significant. Patients with acetaminophen-related ALF required dialysis prior to LT at a significantly higher rate than all other drug groups (27% versus 3%-10%, P < 0.0001). According to Cox proportional hazards regression analysis, the independent pretransplant predictors of death after LT were being on life support, DIALF due to antiepileptic drugs at age less than 18, and elevated serum creatinine. In conclusion, the leading drug groups causing LT due to DIALF in the United States were acetaminophen, antituberculosis drugs, antiepileptics, and antibiotics. Children who had ALF due to antiepileptics had a substantially higher risk of death after LT in comparison with other drugs. Patients transplanted for acetaminophen-related ALF required dialysis at a significantly higher rate. Being on life support, DIALF due to antiepileptics (at age less than 18), and elevated serum creatinine were independent pretransplant predictors of poor survival after LT for DIALF.

The impact of MELD allocation on simultaneous liver-kidney transplantation

Model for End-Stage Liver Disease (MELD) allocation has improved the process for ranking patients on the liver transplant list. One unintended consequence has been an increase in the number of simultaneous liver-kidney (SLK) transplants. Some have argued that the system unfairly advantages patients with kidney disease and that some kidneys are being prematurely placed in SLK transplantation. This review summarizes the MELD score, assessment of kidney function in cirrhosis, the impact of kidney function in liver disease, and changes in kidney function status in liver transplant recipients in the MELD era. Finally, recommendations regarding who should receive SLK transplants are reviewed.