Role of MELD score and serum creatinine as prognostic tools for the development of acute kidney injury after liver transplantation

Combining Acute Kidney Injury Grading and Recovery Mode for Screening in Pediatric Liver Transplantation: A Retrospective Observational Study

BACKGROUND

A growing number of studies indicate that acute kidney injury (AKI) and the pattern of recovery after kidney injury are associated with poor outcomes for grafts and long-term renal function after liver transplantation (LT). However, few systematic studies have been conducted on the pediatric liver transplantation (PLT) population.

MATERIALS AND METHODS

In this single-centered retrospective observational study, according to AKI degree and whether AKI was persistent, patients were divided into three groups: non-AKI/stage 1 AKI, stage 2/3 transient AKI, and stage 2/3 persistent AKI. We compared the survival of patients, graft, and chronic kidney disease (CKD) among the three groups, analyzing the risk factors for the stage 2/3 persistent AKI.

RESULTS

Among 700 patients, the total incidence of AKI was 39.57%; of children with stage 2/3 AKI, the condition was persistent in 38.06%. In the stage 2/3 persistent-AKI group, the risk of graft loss was 3.264× greater than in the no-AKI/stage 1 AKI group and 4.329× greater than in the stage 2/3 transient AKI group. Pediatric End-stage Liver Disease (PELD) score, preoperative estimated glomerular filtration rate (eGFR), duration of vena cava occlusion, postoperative respiratory support time, and postoperative early allograft dysfunction (EAD) were significantly correlated with the occurrence of stage 2/3 persistent AKI.

CONCLUSIONS

By combining AKI recovery mode with AKI grading, clinicians can screen out stage 2/3 persistent AKI with a worse prognosis. This method was more accurate in predicting prognosis than applying AKI grading alone.

Development of a prediction index for persistent acute kidney injury following orthotopic liver transplant

INTRODUCTION AND OBJECTIVES

Acute kidney injury (AKI) is a common complication of orthotopic liver transplantation (OLT). This study aimed to identify factors associated with persistent AKI (pAKI) and to develop a risk index. The impact of pAKI on mortality and renal function over a 5-year period was also assessed.

MATERIALS AND METHODS

In this retrospective cohort study, adult OLT recipients were included. pAKI was defined as AKI lasting >72 hours. Logistic regression identified pAKI-associated factors, which were used to create a risk index. Long-term renal function was then evaluated.

RESULTS

Among 305 patients, 23 % developed pAKI. The median MELD (Model for End-stage Liver Disease) score was 17. Multivariate analysis identified male sex, reoperation, transfusion of >6 units of red blood cells, anhepatic time >50 minutes, and norepinephrine use >0.25 mcg/kg/min as significant risk factors. The risk index assigned 3 points each to male sex and norepinephrine use, and 5 points to the remaining factors. A score ≥11 had moderate performance (AUC 0.70) and a negative predictive value of 90 %. Patients with pAKI had longer ICU and hospital stays and higher in-hospital mortality. At 5 years, overall mortality did not differ significantly, but those with pAKI had a 10 ml/min/1.73m² lower eGFR.

CONCLUSIONS

pAKI is a frequent OLT complication, negatively affecting short-term outcomes and long-term renal function. The proposed risk index effectively identifies patients at low risk, supporting targeted monitoring and prevention.

Prediction models for acute kidney injury following liver transplantation: A systematic review and critical appraisal

OBJECTIVE

This study aims to systematically review and critical evaluation of the risk of bias and the applicability of existing prediction models for acute kidney injury post liver transplantation.

DATA SOURCE

A comprehensive literature search up until February 7, 2024, was conducted across nine databases: PubMed, Web of Science, EBSCO CINAHL Plus, Embase, Cochrane Library, CNKI, Wanfang, CBM, and VIP.

STUDY DESIGN

Systematic review of observational studies.

EXTRACTION METHODS

Literature screening and data extraction were independently conducted by two researchers using a standardized checklist designed for the critical appraisal of prediction modelling studies in systematic reviews. The prediction model risk of bias assessment tool was utilized to assess both the risk of bias and the models' applicability.

PRINCIPAL FINDINGS

Thirty studies were included, identifying 34 prediction models. External validation was conducted in seven studies, while internal validation exclusively took place in eight studies. Three models were subjected to both internal and external validation, the area under the curve ranging from 0.610 to 0.921. A meta-analysis of high-frequency predictors identified several statistically significant factors, including recipient body mass index, Model for End-stage Liver Disease score, preoperative albumin levels, international normalized ratio, and surgical-related factors such as cold ischemia time. All studies were demonstrated a high risk of bias, mainly due to the use of unsuitable data sources and inadequate detail in the analysis reporting.

CONCLUSIONS

The evaluation with prediction model risk of bias assessment tool indicated a considerable bias risk in current predictive models for acute kidney injury post liver transplantation.

IMPLICATIONS FOR CLINICAL PRACTICE

The recognition of high bias in existing models calls for future research to employ rigorous methodologies and robust data sources, aiming to develop and validate more accurate and clinically applicable predictive models for acute kidney injury post liver transplantation.

The Association Between Cytomegalovirus Infection and Kidney Damage in the Liver Transplant Setting

INTRODUCTION

The development of chronic kidney disease (CKD) is a common and significant complication, contributing to morbidity after liver transplantation (LT). Cytomegalovirus (CMV) infection is common in the overall population, and relevant reinfection after LT may occur. CMV-associated kidney damage has been discussed, but the clinical significance on CKD development after LT remains unclear.

METHODS

A total of 745 patients who underwent LT between 2006 and 2017 were included in this retrospective analysis. Clinical data, as well as laboratory parameters, were analyzed. Univariate and multivariate analysis were performed.

RESULTS

The univariate analysis revealed significantly impaired estimated glomerular filtration rates (eGFRs) in patients with histories of CMV infection (81.4 (8-137) mL/min vs. 90.0 (5-147) mL/min; p = 0.004). This effect was confirmed in the multivariate analysis. Post-LT, eGFR was impaired in patients with CMV (re)infection at 6, 12, 36, and 60 months, 10 years, and 15 years after LT. Immunosuppressive levels were comparable between groups. Overall survival was negatively affected by CMV infection (p = 0.001).

DISCUSSION

A clinically significant detrimental impact of CMV infection on renal function was observed, that could individualize clinical risk evaluation prior and after LT further. However, the pathophysiological mechanisms behind this observation are not yet understood.

Impact of Chronic Hepatitis C Virus on Acute Kidney Injury After Living Donor Liver Transplantation

BACKGROUND

Acute kidney injury (AKI) is one of the most common complications after liver transplantation (LT) and can significantly impact outcomes. The presence of hepatitis C virus (HCV) infection increases the risk of AKI development. However, the impact of HCV on AKI after LT has not been evaluated. The aim of this study was to assess the effect of HCV on AKI development in patients who underwent LT.

METHODS

Between January 2008 and April 2023, 2183 patients who underwent living donor LT (LDLT) were included. Patients were divided into 2 groups based on the presence of chronic HCV infection. We compared LT recipients using the propensity score matching (PSM) method. Factors associated with AKI development were evaluated using multiple logistic regression analysis. In addition, 1-year mortality and graft failure were assessed using a Cox proportional regression model.

RESULTS

Among 2183 patients, the incidence of AKI was 59.2%. After PSM, the patients with HCV showed a more frequent development of AKI (71.9% vs 63.9%, P = .026). In multivariate analysis after PSM, HCV was associated with AKI development (odds ratio [OR], 1.53; 95% confidence interval [CI], 1.06-2.20, P = .022), 1-year mortality (Hazard ratio [HR], 1.98; 95% CI, 1.12-3.52, P = .019), and graft failure (HR, 2.12; 95% CI, 1.22-3.69, P = .008).

CONCLUSIONS

The presence of HCV was associated with increased risk for the development of AKI, 1-year mortality, and graft failure after LT.

Association Between Liver Graft to Recipient Weight Ratio and Acute Kidney Injury Following Liver Transplantation: A Historical Cohort Study

INTRODUCTION

Acute kidney injury (AKI) is a frequent complication following liver transplantation (LT) that has a multifactorial etiology. While some perioperative risk factors have been associated with postoperative AKI, the impact of liver graft weight to recipient body weight ratio (GW/RBW) has been poorly explored. We hypothesized that a high GW/RBW ratio would be associated with AKI after LT.

METHODS

This single-center historical cohort study included all consecutive adults who had LT at Paul Brousse Hospital between 2018 and 2022. Patients requiring preoperative renal replacement therapy, combined solid organ transplantation, retransplantation, split or domino graft were excluded, as well as those with missing graft weight and creatinine values during the first postoperative week. The primary exposure was GW/RBW ratio expressed as a proportion. The primary outcome was the incidence of postoperative AKI within 7 days after surgery, defined using the Kidney Disease: Improving Global Outcomes (KDIGO) criteria. The secondary outcome was the AKI severity (KDIGO grades). We estimated logistic and ordinal regression models adjusted for potential confounding factors and explored nonlinear associations.

RESULTS

Of 467 patients analyzed, 211 (45%) developed AKI. A high GW/RBW ratio was associated with both the risk of postoperative AKI and the severity of AKI (KDIGO grades), especially above a threshold of 2.5% (non-linear effect).

CONCLUSION

A high GW/RBW ratio was associated with an exponential increase in the risk of AKI after LT. A high GW/RBW ratio was also associated with an increased AKI severity. Our findings may help improve graft allocation in patients undergoing LT.

The effects of venovenous bypass use in liver transplantation with piggyback technique: a propensity score-weighted analysis

Venovenous bypass (VVB) use during liver transplantation (LT) is notably variable among the centres and it is actually restricted to surgically complex cases, severely unstable recipients or grafts from high-risk donors. Historically, VVB was associated with the classical LT with caval cross clamping, while not much is known about the safety of this technique applied to piggyback LT. This retrospective observational study evaluated the effects of VVB applied to piggyback LT on mortality, hospital outcomes, postoperative graft and other organ dysfunction. We retrospectively collected data about recipient status, surgical complexity and graft quality of all the piggyback LTs performed at the Transplant Unit of IRCCS Azienda Ospedaliero-Universitaria di Bologna, Italy, from January 2012 to December 2022. A propensity score (PS) was built taking into account the variables possibly associated with either VVB choice and the investigated outcomes with the average treatment overlap method. PS-weighted general linear models (GLMs) were developed to investigate the adjusted effect of VVB use on the selected outcomes. The final analysis included 874 LT cases, of whom 74 (8.5%) underwent VVB. The effective sample sizes after PS-weighting were 280.2 and 64.3 patients in the no-VVB and VVB groups, respectively. PS-weighted GLMs did not show any differences regarding hospital and graft-related outcomes. However, significantly higher odds ratios for serum creatinine > 2 mg/dL and AKIN stage 2 or 3 during the first 24 h after ICU admission together with a higher renal replacement therapy need during ICU stay were reported for VVB exposure in the weighted analyses. This study suggests similar mortality and length of stay but a higher risk for postoperative acute kidney injury in patients undergoing piggyback LT with VVB.

Palliative Care in Kidney and Liver Diseases

The role of palliative care is to recognize patients with advanced illnesses who are at risk for poor outcomes and to alleviate their pain and suffering. Patients with both kidney and liver disease are a very vulnerable population due to the unique pathophysiologic relationship these two organs share, which often leads to an abbreviated life expectancy and a significant symptom burden. These patients face many challenges in their care. This article discusses the importance of prognostication for early palliative care referrals as well as the management of the two most common complaints patients with kidney and liver disease face: pain and ascites.

A Retrospective Study of the Role of Perioperative Serum Albumin and the Albumin-Bilirubin Grade in Predicting Post-Liver Transplant Length of Stay

INTRODUCTION

Serum albumin's association with liver transplant outcomes has been investigated with mixed findings. This study aimed to evaluate perioperative albumin level, independently and as part of the albumin-bilirubin (ALBI) grade, as a predictor of post-liver transplant hospital and intensive care unit (ICU) length of stay (LOS).

METHODS

Adult liver-only transplant recipients at our institution from September 2011 to May 2019 were included in this retrospective study. Repeat transplants were excluded. Demographic, laboratory, and hospital course data were extracted from an institutional data warehouse. Negative binomial regression was used to assess the association of LOS with ALBI grade, age, BMI, ASA score, Elixhauser comorbidity index, MELD-Na, warm ischemia time, units of platelets and cryoprecipitate transfused, and preoperative serum albumin.

RESULTS

Six hundred and sixty-three liver transplant recipients met inclusion criteria. The median preoperative serum albumin was 3.1 [2.6-3.6] g/dL. The median postoperative ICU and hospital LOS were 3.8 [2.4-6.8] and 12 [8-20] days, respectively. Preoperative serum albumin predicted hospital but not ICU LOS (ratio .9 [95% confidence interval (CI) .84-.99], P = .03, hospital LOS vs ratio .92 [95% CI 0.84-1.02], P = .10, ICU LOS). For patients with MELD-Na ≤ 20, ALBI grade-3 predicted longer hospital and ICU LOS (ratio 1.40 [95% CI 1.18-1.66], P < .001, hospital LOS vs ratio 1.62 [95% CI 1.32-1.99], P < .001, ICU LOS). These associations were not significant for patients with MELD-Na > 20.

CONCLUSIONS

Serum albumin predicted post-liver transplant hospital LOS. ALBI grade-3 predicted increased hospital and ICU LOS in low MELD-Na recipients.

The urine albumin creatinine ratio is one of the predictors of acute kidney injury in hepatitis C-related cirrhotic hepatic encephalopathy

Background/objective

Hepatic encephalopathy (HE) is a main manifestation of acute decompensation in liver cirrhosis. Recently, systemic inflammation was proposed as a key mechanism in the development of acute kidney injury (AKI) in cirrhotic patients. The urine albumin creatinine ratio (UACR) is considered a marker of systemic inflammation in a variety of clinical settings. Here, we aimed to evaluate the role of the urine albumin creatinine ratio in the early prediction of AKI in HE.

Patients and methods

Sixty-seven consecutive patients presented with cirrhotic HE, and 59 age- and sex-matched cirrhotic patients with no history of HE served as controls. HE was defined and graded by the West Haven criteria. The severity of liver cirrhosis was evaluated by the Child-Turcotte-Pugh (CTP) score, and model for end-stage liver disease (MELD) score. The incidence of AKI that developed during hospital admission and the in-hospital mortality rate was estimated among HE patients. In addition, predictors of AKI were analyzed.

Results

The mean age of HE patients was 58.09±12.26 years; 36 (53.7%) were males, and 31 (46.3%) were females. Among HE patients, 16 (23.9%) developed AKI during hospital admission. The in-hospital mortality rate among HE patients was 22 (32.8%), the in-hospital mortality among HE-AKI patients was 81.3% (n=13/16), and UACR levels > 91.5 mg/g identified HE-AKI with 81.25% sensitivity (AUC = 0.85, P ≤ 0.001).

Conclusions

Patients with cirrhotic HE are at high risk of AKI. HE-AKI patients had a high rate of in-hospital mortality. Estimation of UACR at hospital admission is suggested for the early detection of patients with HE-AKI.

Intraoperative risk factors of acute kidney injury after liver transplantation

Acute kidney injury (AKI) is one of the most common complications of liver transplantation (LT). We examined the impact of intraoperative management on risk for AKI following LT. In this retrospective observational study, we linked data from the electronic health record with standardized transplant outcomes. Our primary outcome was stage 2 or 3 AKI as defined by Kidney Disease Improving Global Outcomes guidelines within the first 7 days of LT. We used logistic regression models to test the hypothesis that the addition of intraoperative variables, including inotropic/vasopressor administration, transfusion requirements, and hemodynamic markers improves our ability to predict AKI following LT. We also examined the impact of postoperative AKI on mortality. Of the 598 adult primary LT recipients included in our study, 43% (n = 255) were diagnosed with AKI within the first 7 postoperative days. Several preoperative and intraoperative variables including (1) electrolyte/acid-base balance disorder (International Classification of Diseases, Ninth Revision codes 253.6 or 276.x and International Classification of Diseases, Tenth Revision codes E22.2 or E87.x, where x is any digit; adjusted odds ratio [aOR], 1.917, 95% confidence interval [CI], 1.280-2.869; p = 0.002); (2) preoperative anemia (aOR, 2.612; 95% CI, 1.405-4.854; p = 0.002); (3) low serum albumin (aOR, 0.576; 95% CI, 0.410-0.808; p = 0.001), increased potassium value during reperfusion (aOR, 1.513; 95% CI, 1.103-2.077; p = 0.01), and lactate during reperfusion (aOR, 1.081; 95% CI, 1.003-1.166; p = 0.04) were associated with posttransplant AKI. New dialysis requirement within the first 7 days postoperatively predicted the posttransplant mortality. Our study identified significant association between several potentially modifiable variables with posttransplant AKI. The addition of intraoperative data did not improve overall model discrimination.

1H‑NMR‑based metabolic profiling of rat urine to assess the toxicity‑attenuating effect of the sweat‑soaking method on Radix Wikstroemia indica

Radix Wikstroemia indica (L.) C.A. Mey. (RWI) is a toxic medicinal species primarily present in the Miao area of China. The toxicity of RWI is effectively reduced whilst maintaining the therapeutic effect when processed using the ‘sweat-soaking method’, which is a common method of Traditional Chinese Medicine preparation. However, there is a lack of scientific and medical evidence to explain the potential mechanisms by which the toxicity of RWI is reduced after preparation using this method, and the endogenous systemic metabolic effect of RWI remains uncertain. The aim of the present study was to explore the endogetnous metabolic alterations caused by RWI and to examine the possibility of reducing the toxicity of RWI using the sweat-soaking method using proton nuclear magnetic resonance (NMR) metabolomic analysis in rats. Principal Component Analysis, Partial Least Squares-Discriminant Analysis (PLS-DA) and Orthogonal PLS-DA were used to assess individual proton NMR spectra. A total of 34 metabolic products were altered after delivering raw RWI, and 32 endogenous metabolites were induced by processed RWI. The metabolic pathways that lead to a significant impact on energy and carbohydrate, amino acid, organic acids and lipid metabolism following raw and processed RWI use were identified. The mitochondria of hepatic and renal tubules of rats were injured in the raw RWI group, whereas the processed product reduced or interfered with energy substrate, carbohydrate and amino acid metabolism, whilst reducing the levels of metabolic markers of hepatotoxicity and nephrotoxicity, without causing damage to the mitochondria. Our previous study showed that the median lethal dose (LD₅₀) value of raw RWI was 4.05 g/kg in rats after oral administration; however, the LD₅₀ value of the processed RWI could not be measured. The maximum tolerated dose and minimum lethal dose were 20 and 30 g/kg for the processed RWI, respectively, corresponding to 109 and 164 times the clinical daily dose (0.029 g/kg). Thus, the sweat-soaking method reduced the toxicity of RWI. Moreover, after processing, the toxic component YH-10 was converted into a YH-10 + OH compound, reducing the content of the toxic YH-10 by 48%, whilst also reducing the contents of the toxic components YH-12 and YH-15 by 44 and 65%, respectively. In conclusion, the present study showed that the sweat-soaking method reduced the toxicity of RWI, as evidenced by the reduction of the levels of metabolic markers and the activity of metabolic pathways, thus providing a basis for processing of RWI for clinical use.

Risk factors and prediction of acute kidney injury after liver transplantation: Logistic regression and artificial neural network approaches

BACKGROUND

Acute kidney injury (AKI) has serious consequences on the prognosis of patients undergoing liver transplantation. Recently, artificial neural network (ANN) was reported to have better predictive ability than the classical logistic regression (LR) for this postoperative outcome.

AIM

To identify the risk factors of AKI after deceased-donor liver transplantation (DDLT) and compare the prediction performance of ANN with that of LR for this complication.

METHODS

Adult patients with no evidence of end-stage kidney dysfunction (KD) who underwent the first DDLT according to model for end-stage liver disease (MELD) score allocation system was evaluated. AKI was defined according to the International Club of Ascites criteria, and potential predictors of postoperative AKI were identified by LR. The prediction performance of both ANN and LR was tested.

RESULTS

The incidence of AKI was 60.6% (n = 88/145) and the following predictors were identified by LR: MELD score > 25 (odds ratio [OR] = 1.999), preoperative kidney dysfunction (OR = 1.279), extended criteria donors (OR = 1.191), intraoperative arterial hypotension (OR = 1.935), intraoperative massive blood transfusion (MBT) (OR = 1.830), and postoperative serum lactate (SL) (OR = 2.001). The area under the receiver-operating characteristic curve was best for ANN (0.81, 95% confidence interval [CI]: 0.75-0.83) than for LR (0.71, 95%CI: 0.67-0.76). The root-mean-square error and mean absolute error in the ANN model were 0.47 and 0.38, respectively.

CONCLUSION

The severity of liver disease, pre-existing kidney dysfunction, marginal grafts, hemodynamic instability, MBT, and SL are predictors of postoperative AKI, and ANN has better prediction performance than LR in this scenario.

Artificial neural network for prediction of acute kidney injury after liver transplantation for cirrhosis and hepatocellular carcinoma

Acute kidney injury (AKI) has serious consequences on the prognosis of patients undergoing liver transplantation (LT) for liver cancer and cirrhosis. Artificial neural network (ANN) has recently been proposed as a useful tool in many fields in the setting of solid organ transplantation and surgical oncology, where patient prognosis depends on a multidimensional and nonlinear relationship between variables pertaining to the surgical procedure, the donor (graft characteristics), and the recipient comorbidities. In the specific case of LT, ANN models have been developed mainly to predict survival in patients with cirrhosis, to assess the best donor-to-recipient match during allocation processes, and to foresee postoperative complications and outcomes. This is a specific opinion review on the role of ANN in the prediction of AKI after LT for liver cancer and cirrhosis, highlighting potential strengths of the method to forecast this serious postoperative complication.

Frequency and Characteristics of Overestimated Renal Function in Japanese Patients with Chronic Liver Disease and Its Relation to Sarcopenia

Renal dysfunction and sarcopenia are important prognostic factors in patients with chronic liver disease (CLD). Muscle atrophy can cause the overestimation of renal function based on serum creatinine. However, the frequency of overestimated renal function in Japanese patients with CLD and its relationship with sarcopenia are unclear. In present study, we evaluated the frequency of overestimated renal function, defined as a >20% higher eGFR using creatinine than using cystatin C, in 307 patients with CLD as well as its relationship with indicators of sarcopenia. In total, 24.8% of patients had overestimated renal function. In a multivariate regression analysis, liver cirrhosis (p = 0.004) and psoas muscle mass index (p = 0.049) were significantly associated with overestimated renal function. Loss of skeletal muscle mass was significantly more frequent in both male and female patients with overestimated renal function than without. In males, the loss of muscle strength and rate of sarcopenia, defined as loss of muscle mass and strength, were significantly higher in patients with than without overestimated renal function. The high frequency of overestimated renal function in Japanese patients suggests that indicators of renal function should be carefully considered; furthermore, monitoring and interventions for both renal function and sarcopenia are needed in patients with CLD.

Application of machine learning models for predicting acute kidney injury following donation after cardiac death liver transplantation

BACKGROUND

Acute kidney injury (AKI) is a common complication after liver transplantation (LT) and is an indicator of poor prognosis. The establishment of a more accurate preoperative prediction model of AKI could help to improve the prognosis of LT. Machine learning algorithms provide a potentially effective approach.

METHODS

A total of 493 patients with donation after cardiac death LT (DCDLT) were enrolled. AKI was defined according to the clinical practice guidelines of kidney disease: improving global outcomes (KDIGO). The clinical data of patients with AKI (AKI group) and without AKI (non-AKI group) were compared. With logistic regression analysis as a conventional model, four predictive machine learning models were developed using the following algorithms: random forest, support vector machine, classical decision tree, and conditional inference tree. The predictive power of these models was then evaluated using the area under the receiver operating characteristic curve (AUC).

RESULTS

The incidence of AKI was 35.7% (176/493) during the follow-up period. Compared with the non-AKI group, the AKI group showed a remarkably lower survival rate (P < 0.001). The random forest model demonstrated the highest prediction accuracy of 0.79 with AUC of 0.850 [95% confidence interval (CI): 0.794-0.905], which was significantly higher than the AUCs of the other machine learning algorithms and logistic regression models (P < 0.001).

CONCLUSIONS

The random forest model based on machine learning algorithms for predicting AKI occurring after DCDLT demonstrated stronger predictive power than other models in our study. This suggests that machine learning methods may provide feasible tools for forecasting AKI after DCDLT.

Changes in the estimated renal function after hepatitis C virus eradication with direct-acting antiviral agents: Impact of changes in skeletal muscle mass

Hepatitis C virus (HCV) infection can cause renal dysfunction, expected to improve upon HCV eradication. However, adverse effects of HCV eradication using direct-acting antiviral agents (DAAs) on renal function have been recently reported. This retrospective study aimed to evaluate renal function with glomerular filtration rate (eGFR) estimated using creatinine (eGFRcre) and cystatin C (eGFRcys). Complete clinical information and preserved serum samples were collected from 207 patients with HCV infection treated with interferon-free DAA at baseline and SVR48 (SVR48). Patients who underwent paired computed tomography (CT) at baseline and ≥12 months after DAA were evaluated for changes in skeletal muscle mass using the psoas muscle mass index (PMI). eGFRcre significantly worsened at SVR48, while eGFRcys was similar at baseline and SVR48. At baseline, eGFRcre was significantly higher than eGFRcys; eGFRcre and eGFRcys were similar at SVR48. Multivariate analysis revealed that the presence of liver cirrhosis and low-albumin level, as well as cirrhosis and age, was significantly associated with the overestimation of renal function by eGFRcre at baseline and SVR48, respectively. In the 57 patients who underwent paired CT at baseline and ≥12 months after DAA, relative values of PMI significantly increased after DAA. After DAA, in patients with increased PMI (65% 37/57), eGFRcre significantly worsened but did not change in patients without increased PMI. eGFRcre significantly worsened after DAAs; however, this might not reflect accurate changes in renal function, partially because of changes in skeletal muscle mass. eGFRcys did not change after DAAs, and it is a potential alternative to eGFRcre.

Intraoperative hypotension during liver transplant surgery is associated with postoperative acute kidney injury: a historical cohort study

Background

Acute kidney injury (AKI) occurs frequently after liver transplant surgery and is associated with significant morbidity and mortality. While the impact of intraoperative hypotension (IOH) on postoperative AKI has been well demonstrated in patients undergoing a wide variety of non-cardiac surgeries, it remains poorly studied in liver transplant surgery. We tested the hypothesis that IOH is associated with AKI following liver transplant surgery.

Methods

This historical cohort study included all patients who underwent liver transplant surgery between 2014 and 2019 except those with a preoperative creatinine > 1.5 mg/dl and/or who had combined transplantation surgery. IOH was defined as any mean arterial pressure (MAP) < 65 mmHg and was classified according to the percentage of case time during which the MAP was < 65 mmHg into three groups, based on the interquartile range of the study cohort: “short” (Quartile 1, < 8.6% of case time), “intermediate” (Quartiles 2–3, 8.6–39.5%) and “long” (Quartile 4, > 39.5%) duration. AKI stages were classified according to a “modified” “Kidney Disease: Improving Global Outcomes” (KDIGO) criteria. Logistic regression modelling was conducted to assess the association between IOH and postoperative AKI. The model was run both as a univariate and with multiple perioperative covariates to test for robustness to confounders.

Results

Of the 205 patients who met our inclusion criteria, 117 (57.1%) developed AKI. Fifty-two (25%), 102 (50%) and 51 (25%) patients had short, intermediate and long duration of IOH respectively. In multivariate analysis, IOH was independently associated with an increased risk of AKI (adjusted odds ratio [OR] 1.05; 95%CI 1.02–1.09; P < 0.001). Compared to “short duration” of IOH, “intermediate duration” was associated with a 10-fold increased risk of developing AKI (OR 9.7; 95%CI 4.1–22.7; P < 0.001). “Long duration” was associated with an even greater risk of AKI compared to “short duration” (OR 34.6; 95%CI 11.5-108.6; P < 0.001).

Conclusions

Intraoperative hypotension is independently associated with the development of AKI after liver transplant surgery. The longer the MAP is < 65 mmHg, the higher the risk the patient will develop AKI in the immediate postoperative period, and the greater the likely severity. Anesthesiologists and surgeons must therefore make every effort to avoid IOH during surgery.

Pre- and intraoperative predictors of acute kidney injury after liver transplantation

BACKGROUND

Acute kidney injury (AKI) after liver transplantation (LT) is a frequent and multifactorial event related to increased morbidity and mortality. Risk factors for AKI after LT still need to be clarified.

AIM

To identify the predictors of acute kidney injury after liver transplantation.

METHODS

The frequency and pre- and intraoperative predictors of AKI within the first 7 d after LT were evaluated in adult liver transplant candidates in a single LT center in Croatia. AKI was defined according to the Kidney Disease: Improving Global Outcomes criteria.

RESULTS

Out of 205 patients (mean age 57 ± 10 years; 73.7% males, 52.7% with alcohol-related liver disease) 93 (45.36%) developed AKI, and the majority of them (58.06%) had stage 1. Only 5.38% of patients required renal replacement therapy after LT. The majority of patients (82.8%) developed AKI within the first two days after the procedure. Multivariate logistic regression identified pre-LT body mass index (OR = 1.1, 95%CI: 1.05-1.24) and red blood cell transfusion (OR = 1.66, 95%CI: 1.09-2.53) as independent predictors of early post-LT AKI occurrence. 30-d survival after LT was significantly better for patients without AKI (P = 0.01).

CONCLUSION

Early AKI after LT is a frequent event that negatively impacts short-term survival. The pathogenesis of AKI is multifactorial, but pre-LT BMI and intraoperative volume shifts are major contributors.

Early Acute Kidney Injury Associated with Liver Transplantation: A Retrospective Case-Control Study

Background

A retrospective case-control study was carried out to assess the occurrence of acute kidney injury (AKI) in liver transplantation (LT) recipients and its related risk factors.

Material/Methods

The study enrolled 131 patients undergoing LT from December 2017 to June 2019 at Beijing Tsinghua Chang Gung Hospital, China. AKI and its classification were defined according to KDIGO guidelines. We collected patients’ demographic characteristics and perioperative parameters, and identified independent risk factors of AKI by multivariate logistic regression analysis.

Results

We included 122 patients in analysis. AKI occurred in 52 (42.6%) patients (22.1% stage I, 8.2% stage II, and 12.3% stage III). AKI was notably associated with 12 factors: sex, body mass index (BMI), hepatic etiology, MELD score, ascites, prothrombin time (PT), international normalized ratio of prothrombin time (INR), preoperative total bilirubin (TBIL), operative time, total fluid intake, fresh frozen plasma (FFP), and estimated blood loss (EBL) (P<0.05). The factors independently associated with AKI were BMI (adjusted odds ratio: 0.605, 95% confidence interval: 0.425–0.859; P=0.005) and intraoperative FFP infusion (adjusted odds ratio: 0.998, 95% confidence interval: 0.995–1.000; P=0.047). Compared with the non-AKI group, the AKI group showed higher likelihood of renal replacement therapy (RRT), and longer ICU and hospital stays, higher in-hospital mortality, and higher hospitalization costs (P<0.05).

Conclusions

There is a high risk of AKI in patients undergoing LT. BMI and intraoperative FFP infusion are factors independently correlated with AKI. AKI can result in extended hospital stays and higher hospitalization expenses.

Association of post-reperfusion syndrome and ischemia-reperfusion injury with acute kidney injury after liver transplantation

BACKGROUND

Acute kidney injury (AKI) is frequently observed after orthotopic liver transplantation (OLT) even in patients with previously normal renal function. In this study, we investigated the impact of factors such graft steatosis, post-reperfusion syndrome (PRS), and hepatic ischemia reperfusion injury (HIRI) on the development of AKI after OLT in adult patients.

METHODS

We retrospectively examined consecutive adult patients who underwent OLT at our institution between July 2011 and June 2017. AKI was diagnosed based on the criteria proposed by the International Kidney Disease Improving Global Outcomes (KDIGO) workgroup. Peak aspartate aminotransferase (AST) level within 72 hours after OLT was used as a surrogate marker for HIRI. Graft steatosis was diagnosed by histopathological examination using specimens biopsied intraoperatively at the end of transplantation procedure and categorized as <10%, 10%-20%, 20%-30%, and ≥30% of hepatic steatosis.

RESULTS

Out of 386 patients, 141 (37%) developed AKI (KDIGO stage 1:71 patients; stage 2:29 patients; stage 3:41 patients). Multivariable logistic regression analysis revealed that cold ischemic time (P = .012) and HIRI (P = .007) were independent risk factors for post-OLT AKI. Multivariable analysis also revealed that graft steatosis was associated with HIRI but not directly with AKI. PRS was not associated with HIRI or AKI in the multivariable analyses.

CONCLUSION

Our results indicate that greater severity of liver graft injury during transplantation negatively affects renal function after OLT. As expected, the severity of liver graft steatosis contributes to accelerated liver injury occurring during the transplantation procedure.

Incidence, Mortality and Predictors of Acute Kidney Injury in Patients with Cirrhosis: A Systematic Review and Meta-analysis

Background and Aims: Acute kidney injury (AKI) is common in patients with cirrhosis but the incidence is heterogeneous among studies. We performed a meta-analysis to describe the incidence of AKI and its impact on patient mortality in patients with cirrhosis. We also evaluated the admission variables predicting development of AKI. Methods: A systematic search of various databases was performed up to November 2018. Meta-analyses were performed using random effects models. Results: Of 18,474 patients with cirrhosis from 30 selected studies, 5,648 developed AKI, with a pooled incidence of 29% (95% confidence interval [CI]: 28-30%, I 2 of 99%). In-hospital mortality assessed in eight studies was six-fold higher among AKI patients, as compared to those without AKI (odds ratio [OR] 6.72, 95% CI: 3.47-13, p<0.0001, I 2 of 70%). Three studies on patients admitted to intensive care showed about six-fold higher mortality among AKI patients (OR 5.90, 95% CI: 3.21-10.85, p>0.0001). Mortality remained significantly high, at days 30 and 90 and even at 1-year follow up after development of AKI. Of 12 admission variables analyzed, model for end-stage liver disease score, Child-Pugh-Turcotte stage C, presence of ascites, and presence of sepsis/septic shock were statistically significant risk factors for AKI. Conclusions: AKI occurred in about 29% of patients with cirrhosis and is associated with a six-fold increased risk of in-hospital mortality. Mortality remained high even in long-term follow-up of 1 year. Patients at risk for AKI development can be recognized at admission. Prospective studies are needed to develop strategies for improving outcome of these patients.

Terlipressin Is Superior to Noradrenaline in the Management of Acute Kidney Injury in Acute on Chronic Liver Failure

Hepatorenal syndrome (HRS) carries a high short-term mortality in patients with cirrhosis and acute on chronic liver failure (ACLF). Terlipressin and noradrenaline are routinely used in cirrhosis with HRS and have been found to be equally effective. There are no data comparing the efficacy of terlipressin with noradrenaline in ACLF patients with HRS. In an open-label, randomized controlled trial (RCT), consecutive patients with ACLF diagnosed with HRS acute kidney injury (AKI) were randomized to albumin with infusion of terlipressin (2-12 mg/day; n = 60) or noradrenaline (0.5-3.0 mg/h; n = 60). Response to treatment, course of AKI, and outcome were studied. Baseline characteristics, including AKI stage and sepsis-related HRS-AKI, were comparable between groups. Compared to noradrenaline, terlipressin achieved greater day 4 (26.1% vs. 11.7%; P = 0.03) and day 7 (41.7% vs. 20%; P = 0.01) response. Reversal of HRS was also better with terlipressin (40% vs. 16.7%; P = 0.004), with a significant reduction in the requirement of renal replacement therapy (RRT; 56.6% vs. 80%; P = 0.006) and improved 28-day survival (48.3% vs. 20%; P = 0.001). Adverse events limiting use of drugs were higher with terlipressin than noradrenaline (23.3% vs. 8.3%; P = 0.02), but were reversible. On multivariate analysis, high Model for End-Stage Liver Disease (MELD; odds ratio [OR], 1.10; confidence interval [CI] = 1.009-1.20; P = 0.03) and noradrenaline compared to terlipressin (OR, 3.05; CI = 1.27-7.33; P = 0.01) predicted nonresponse to therapy. Use of noradrenaline compared to terlipressin was also predictive of higher mortality (hazard ratio [HR], 2.08; CI = 1.32-3.30; P = 0.002). Conclusion: AKI in ACLF carries a high mortality. Infusion of terlipressin gives earlier and higher response than noradrenaline, with improved survival in ACLF patients with HRS-AKI.

Renal damage after liver transplantation

Background: Patients following liver transplantation are at risk to develop acute kidney injury (AKI). The aim of our study was to assess risk factors for the development of AKI and the impact of AKI on the outcome of patients after liver transplantation (OLT).

Patients and methods: In this retrospective study, we analyzed 149 patients undergoing OLT from 1/2004 to 12/2007. AKI was defined according to the KDIGO definition representing the AKIN and the RIFLE classification, and according to the need for renal replacement therapy (RRT).

Results: According to the AKIN criteria alone 14 patients, according to the RIFLE criteria alone no patient and according to both definitions 30 patients developed AKI. RRT was required in 54 patients experiencing AKI, whereas 51 patients did not develop AKI. Pre OLT serum creatinine (SCr) significantly predicted the development of AKI requiring RRT, but not AKI without RRT requirement. Survival rate was significantly inferior after 28 days, one or three years in patients with AKI requiring RRT (70.4, 46.4, 44.4% vs. 100, 92.2, 90.2%, P < 0.001). There was no difference in survival between patients experiencing AKI according to the RIFLE or AKIN criteria without RRT requirement and patients without AKI.

Conclusion: Pre OLT renal dysfunction assessed by SCr was the most important risk factor predicting severe forms of AKI, but not milder forms of AKI. AKI requiring RRT had a detrimental impact on patients’ survival, whereas milder forms of AKI were not associated with a worse outcome.

Predictive Impact of Modified-Prognostic Nutritional Index for Acute Kidney Injury within 1-week after Living Donor Liver Transplantation

Background. Acute kidney injury (AKI) is one of the common complications after living donor liver transplantation (LDLT) and is associated with increased mortality and morbidity. The prognostic nutritional index (PNI) has been used as a predictive model for postoperative complications. Here, we create a new predictive model based on the PNI and compared its predictive accuracy to other models in patients who underwent LDLT. Material and Methods: The data from 423 patients were collected retrospectively. The patients were dichotomized into the non-AKI and the AKI groups. Multivariate adjustment for significant postoperative variables based on univariate analysis was performed. A new predictive model was created using the results from logistic regression analysis, dubbed the modified-PNI model (mPNI). The area under the receiver operating characteristic curve (AUC) was generated to determine the diagnostic accuracy and cutoff value of individual models. The net reclassification improvement (NRI) and integrated discrimination improvement (IDI) were calculated to investigate diagnostic improvement by the mPNI. Results: Fifty-four patients (12.7 %) were diagnosed with AKI within 1-week after LDLT. The mPNI had the highest predictive accuracy (AUC = 0.823). The model of end-stage liver disease (MELD) scores and PNI were 0.793 and 0.749, respectively, and the INR and serum bilirubin were 0.705 and 0.637, respectively. The differences in the AUCs were statistically significant among the mPNI, PNI, INR, and serum bilirubin. The cutoff value for mPNI was 8.7. The NRI was 10.4% and the IDI was 3.3%. Conclusions: The mPNI predicted AKI within 1-week better than other scoring systems in patients who underwent LDLT. The recommended cutoff value of mPNI is 8.7.

The AKI Prediction Score: a new prediction model for acute kidney injury after liver transplantation

BACKGROUND

Acute kidney injury (AKI) is a frequent complication after liver transplantation. Although numerous risk factors for AKI have been identified, their cumulative impact remains unclear. Our aim was therefore to design a new model to predict post-transplant AKI.

METHODS

Risk analysis was performed in patients undergoing liver transplantation in two centres (n = 1230). A model to predict severe AKI was calculated, based on weight of donor and recipient risk factors in a multivariable regression analysis according to the Framingham risk-scheme.

RESULTS

Overall, 34% developed severe AKI, including 18% requiring postoperative renal replacement therapy (RRT). Five factors were identified as strongest predictors: donor and recipient BMI, DCD grafts, FFP requirements, and recipient warm ischemia time, leading to a range of 0-25 score points with an AUC of 0.70. Three risk classes were identified: low, intermediate and high-risk. Severe AKI was less frequently observed if recipients with an intermediate or high-risk were treated with a renal-sparing immunosuppression regimen (29 vs. 45%; p = 0.007).

CONCLUSION

The AKI Prediction Score is a new instrument to identify recipients at risk for severe post-transplant AKI. This score is readily available at end of the transplant procedure, as a tool to timely decide on the use of kidney-sparing immunosuppression and early RRT.

Randomized Sirolimus-based Early Calcineurin Inhibitor Reduction in Liver Transplantation: Impact on Renal Function

BACKGROUND

The long-term use of calcineurin inhibitors (CNIs) after liver transplantation (LT) is associated with nephrotoxicity.

METHODS

Five-year follow-up data were retrieved from the randomized controlled multicenter SiLVER trial. Standard CNI-based mammalian target of rapamycin-free immunosuppression (group A, n = 264) was compared with a 50% reduction of CNI and introduction of the mammalian target of rapamycin inhibitor Sirolimus (SIR) within 4-6 weeks after LT (group B, n = 261).

RESULTS

Median MELD at LT was low with 10 (7-15) (group A) and 11 (8-15) (group B) in the intention-to-treat approach. CNI dose and CNI trough were reduced by 20% and 8% (group A) versus 55% and 56% (group B) at 3 months posttransplantation. Renal function was preserved at 3 months after LT in the SIR arm (estimated glomerular filtration rate 74 [57-95] versus 67 [55-85] mL/min/1.73m2 P = 0.004) but was similarly impaired thereafter compared with group A. The per protocol analysis identified LT recipients in group B with concomitant early CNI minimization and SIR treatment ≥ year 1 with significantly superior estimated glomerular filtration rate and lowest rate of chronic kidney disease (≥stage 3) from year 1 onwards until study end. Competing risk factors for renal disease (arterial hypertension, fat metabolism disorder, and hyperglycemia) were not associated with worse kidney function.

CONCLUSIONS

Prevention of CNI nephrotoxicity by SIR-based early CNI minimization protects renal function only short-term after LT in the intention-to-treat analysis of this low MELD cohort. Yet, selected LT recipients compliant with early CNI minimization and SIR maintenance achieved better long-term renal outcomes compared with real-world practice.

Estimation of renal function in patients with liver cirrhosis: Impact of muscle mass and sex

BACKGROUND & AIMS

Accurate evaluation of renal function in patients with liver cirrhosis is critical for clinical management. However, there are still discrepancies between the measured glomerular filtration rate (mGFR) and creatinine-based estimated GFR (eGFR). In this study, we compared the performance of 2 common eGFR measurements with mGFR and evaluated the impact of low muscle mass on overestimation of renal function in patients with cirrhosis.

METHODS

This study included 779 consecutive cirrhotic patients who underwent ⁵¹Cr-ethylenediamine tetra acetic acid (EDTA) (as a mGFR) and abdominal computed tomography (CT). The eGFR was calculated using creatinine or cystatin C. Muscle mass was assessed in terms of the total skeletal muscle at L3 level using CT.

RESULTS

Modification of diet in renal disease (MDRD)-eGFR was overestimated in 47% of patients. A multivariate analysis showed that female sex (adjusted odds ratio [aOR] 4.91), Child B and C vs. A (aOR 1.69 and 1.84) and skeletal muscle mass (aOR 0.89) were independent risk factors associated with overestimation. Interestingly, the effect of skeletal muscle mass on overestimation varied based on sex. Decreased muscle mass significantly enhanced the risk of overestimation of MDRD-eGFR in male patients, but not in female patients. Cystatin C-based eGFR showed a better correlation with mGFR than MDRD-eGFR; it was also better at predicting overall survival and the incidence of acute kidney injury than MDRD-eGFR.

CONCLUSIONS

The risk factors associated with overestimation included female sex, impaired liver function, and decreased muscle mass in males. In particular, eGFR in male patients with sarcopenia should be carefully interpreted. Creatinine-based eGFR was overestimated more often than cystatin C-based eGFR, with overestimation of eGFR closely related to poor prognostic performance.

LAY SUMMARY

Overestimation of renal function frequently occurs in patients with liver cirrhosis when using serum creatinine. Decreased muscle mass has a great impact on overestimation of kidney function especially in male patients with cirrhosis. Compared with creatinine, cystatin C was more closely correlated with measured glomerular filtration rate and had a higher predictive ability for renal complications and survival than creatinine.

Bleeding Complications and Clinical Safety of Endoscopic Retrograde Cholangiopancreatography in Patients with Liver Cirrhosis

PURPOSE

Patients with liver cirrhosis are considered to be at risk for additional adverse events during endoscopic retrograde cholangiopancreatography (ERCP). The present study was designed as a propensity-score matched analysis to investigate whether cirrhotic liver increases the risk of bleeding complications in patients undergoing ERCP.

MATERIALS AND METHODS

In total, 8554 patients who underwent ERCP from January 2005 to December 2015 were retrospectively analyzed. To adjust for the imbalance between patients with and those without liver cirrhosis, 1:3 propensity score matching was performed according to age and sex.

RESULTS

Liver cirrhosis was identified in 264 (3.1%) patients. After propensity score matching, a total of 768 patients were included in each of the cirrhotic (n=192) and non-cirrhotic groups (n=576). Post-procedure bleeding (10.9% vs. 4.7%, p=0.003) was more frequently observed in patients with liver cirrhosis than in those without. In multivariate analyses, liver cirrhosis was identified as an independent risk factor associated with post-ERCP bleeding (p=0.003) after further adjustment for prothrombin time, antiplatelet/coagulant, duration of ERCP, and stent insertion. Child-Pugh (CP) class C was found to be associated with an increased incidence of post-ERCP bleeding in patients with cirrhosis (odds ratio 6.144, 95% confidence interval 1.320-28.606; p=0.021).

CONCLUSION

The incidence of post-ERCP bleeding in patients with liver cirrhosis was higher than that in patients without liver cirrhosis. In particular, CP class C cirrhosis was significantly associated with post-ERCP bleeding.

Incidence and Impact of Acute Kidney Injury after Liver Transplantation: A Meta-Analysis

BACKGROUND

The study's aim was to summarize the incidence and impacts of post-liver transplant (LTx) acute kidney injury (AKI) on outcomes after LTx.

METHODS

A literature search was performed using the MEDLINE, EMBASE and Cochrane Databases from inception until December 2018 to identify studies assessing the incidence of AKI (using a standard AKI definition) in adult patients undergoing LTx. Effect estimates from the individual studies were derived and consolidated utilizing random-effect, the generic inverse variance approach of DerSimonian and Laird. The protocol for this systematic review is registered with PROSPERO (no. CRD42018100664).

RESULTS

Thirty-eight cohort studies, with a total of 13,422 LTx patients, were enrolled. Overall, the pooled estimated incidence rates of post-LTx AKI and severe AKI requiring renal replacement therapy (RRT) were 40.7% (95% CI: 35.4%⁻46.2%) and 7.7% (95% CI: 5.1%⁻11.4%), respectively. Meta-regression showed that the year of study did not significantly affect the incidence of post-LTx AKI (p = 0.81). The pooled estimated in-hospital or 30-day mortality, and 1-year mortality rates of patients with post-LTx AKI were 16.5% (95% CI: 10.8%⁻24.3%) and 31.1% (95% CI: 22.4%⁻41.5%), respectively. Post-LTx AKI and severe AKI requiring RRT were associated with significantly higher mortality with pooled ORs of 2.96 (95% CI: 2.32⁻3.77) and 8.15 (95%CI: 4.52⁻14.69), respectively. Compared to those without post-LTx AKI, recipients with post-LTx AKI had significantly increased risk of liver graft failure and chronic kidney disease with pooled ORs of 3.76 (95% CI: 1.56⁻9.03) and 2.35 (95% CI: 1.53⁻3.61), respectively.

CONCLUSION

The overall estimated incidence rates of post-LTx AKI and severe AKI requiring RRT are 40.8% and 7.0%, respectively. There are significant associations of post-LTx AKI with increased mortality and graft failure after transplantation. Furthermore, the incidence of post-LTx AKI has remained stable over the ten years of the study.

Piggyback or Cava Replacement: Which Implantation Technique Protects Liver Recipients From Acute Kidney Injury and Complications?

The cava-preserving piggyback (PB) technique requires only partial cava clamping during the anhepatic phase in liver transplantation (LT) and, therefore, maintains venous return and may hemodynamically stabilize the recipient. Hence, it is an ongoing debate whether PB implantation is more protective from acute kidney injury (AKI) after LT when compared with a classic cava replacement (CR) technique. The aim of this study was to assess the rate of AKI and other complications after LT comparing both transplant techniques without the use of venovenous bypass. We retrospectively analyzed the adult donation after brain death LT cohort between 2008 and 2016 at our center. Liver and kidney function and general outcomes including complications were assessed. Overall 378 transplantations were analyzed, of which 177 (46.8%) were performed as PB and 201 (53.2%) as CR technique. AKI occurred equally often in both groups. Transient renal replacement therapy was required in 22.6% and 22.4% comparing the PB and CR techniques (P = 0.81). Further outcome parameters including the complication rate were similar in both cohorts. Five-year graft and patient survival were comparable between the groups with 81% and 85%, respectively (P = 0.48; P = 0.58). In conclusion, both liver implantation techniques are equal in terms of kidney function and overall complications following LT.

Correlation Between MELD and UNa/K Ratio in Predicting Renal Dysfunction in Cirrhotic Patients

BACKGROUND

Renal dysfunction is one of the dreaded complications of cirrhosis. MELD is a validated chronic liver disease (CLD) severity scoring system. Urinary (U) Na/K ratio closely correlates with renal dysfunction in terms of low GFR in cirrhotic patients.

PATIENTS AND METHODS

All consecutive patients with decompensated cirrhosis between the age of 18 to 70 years, of either gender, presenting in the outpatients' department of Sindh Institute of Urology and Transplantation, Karachi, from June 2015 to June 2017 were included. The MELD score was calculated and the UNa/K ratio less than 1 was taken as surrogate marker of renal dysfunction. Statistical analysis was performed by SPSS (version 20.0).

RESULTS

A total of 71 patients were enrolled. The mean age was 43.79 years and majority were male (67.6%). The most common cause of liver cirrhosis was HCV, found in 42 (59.2%) patients. The mean CTP score was 10.48 ± 2.069 (range: 6-14) with majority of the patients following in class C, that is, 48 (67.6%). Mean MELD score was 21.75 ± 8.96 (range: 8-43). In 57 patients (80.3%), MELD score was > 15.The mean serum creatinine and mean serum sodium were 1.5 ± 1.1 mg/dl (range: 0.37-5.3) and 133.79 ± 6.9 mmol/L (range: 112-152), respectively. Mean urinary sodium and urinary potassium were 38.60 ± 46.64 mmol/L (range: 5-181) and 38.15 ± 23.9 mmol/L (range: 4.3-112), respectively. In majority of study population, UNa/K ratio was below 1, that is, in 52 patients (73.2%). Statistically significant correlation was documented between MELD score and UNa/K ratio (ɤ = 0.34, P = 0.004).

CONCLUSION

The inverse correlation between MELD scores and UNa/K ratio indicates that patients with CLD and higher MELD scores might have renal dysfunction. This finding however should be corroborated by large scale studies.

Prognostic Value of Model for End-Stage Liver Disease Incorporating with Serum Sodium Score for Development of Acute Kidney Injury after Liver Transplantation

Background

Contribution of model for end-stage liver disease incorporating with serum sodium (MELD-Na) score in predicting acute kidney injury (AKI) after orthotopic liver transplantation (OLT) is yet to be identified. This study assessed the prognostic value of MELD-Na score for the development of AKI following OLT.

Methods

Preoperative and surgery-related variables of 321 adult end-stage liver disease patients who underwent OLT in Fuzhou General Hospital were collected. Postoperative AKI was defined and staged in accordance with the clinical practice guidelines developed by Kidney Disease: Improving Global Outcomes. Univariate and multivariate analysis was performed to determine the risk factors for AKI following OLT. The discriminating power of MELD/MELD-Na score on AKI outcome was evaluated by receiver operating characteristic (ROC) curve. Spearman's correlation analysis was used for identifying the correlated relationship between MELD/MELD-Na score and the severity levels of AKI.

Results

The prevalence of AKI following OLT was in 206 out of 321 patients (64.2%). Three risk factors for AKI post-OLT were presented, preoperative calculated MELD score (odds ratio [OR] = 1.048, P = 0.021), intraoperative volume of red cell suspension transfusion (OR = 1.001, P = 0.002), and preoperative liver cirrhosis (OR = 2.015, P = 0.012). Two areas under ROC curve (AUCs) of MELD/MELD-Na score predicting AKI were 0.688 and 0.672, respectively; the difference between two AUCs was not significant (Z = 1.952, P = 0.051). The Spearman's correlation coefficients between MELD/MELD-Na score and the severity levels of AKI were 0.406 and 0.385 (P = 0.001, 0.001), respectively.

Conclusions

We demonstrated that preoperative MELD score, intraoperative volume of red cell suspension transfusion and preoperative liver cirrhosis were risk factors for AKI following OLT. Furthermore, we preliminarily validated that MELD score seemed to have a stronger power discriminating AKI post-OLT than that of novel MELD-Na score.

Perioperative Acute Kidney Injury: Risk Factors and Predictive Strategies

Acute kidney injury (AKI) is a common complication in surgical patients and is associated with increases in mortality, an increased risk for chronic kidney disease and hemodialysis after discharge, and increased cost. Better understanding of the risk factors that contribute to perioperative AKI has led to improved AKI prediction and will eventually lead to improved prevention of AKI, mitigation of injury when AKI occurs, and enhanced recovery in patients who sustain AKI. The development of advanced clinical prediction scores for AKI, new imaging techniques, and novel biomarkers for early detection of AKI provides new tools toward these ends.

Remodeling the model for end-stage liver disease for predicting mortality risk in critically ill patients with cirrhosis and acute kidney injury

Serum creatinine measurement demonstrates a poor specificity and sensitivity for the early diagnosis of acute kidney injury (AKI) in patients with cirrhosis. The existing model for end-stage liver disease (MELD) score reveals multiple pitfalls in critically ill patients with cirrhosis and acute kidney injury (CAKI). The aim of this study was to re-evaluate the role of creatinine values in the existing MELD score and to develop a novel score for CAKI, named the "acute kidney injury-model for end-stage liver disease score" (AKI-MELD score). We extracted 651 CAKI from the Multiparameter Intelligent Monitoring in Intensive Care database. A time-dependent Cox regression analysis was performed for developing remodeled MELD scores (Reweight-MELD score, Del-Cr-MELD score, and AKI-MELD score). The area under the receiver operating characteristic curve provided the discriminative power of scoring models related to outcome. The hazard ratio of creatinine was 1.104 (95% confidence interval [CI], 0.945-1.290; P = 0.211). Reweight-MELD score and Del-Cr-MELD score (decreasing the weight of creatinine) were superior to the original MELD score (all P < 0.001). The new AKI-MELD score consists of bilirubin, the international normalized ratio, and the ratio of creatinine in 48 hours to creatinine at admission. It had competitive discriminative ability for predicting mortality (area under the receiver operating characteristic curve, 0.720 [95% CI, 0.653-0.762] at 30 days, 0.688 [95% CI, 0.630-0.742] at 90 days, and 0.671 [95% CI, 0.612-0.725] at 1 year). Further, AKI-MELD score had significantly higher predictive ability in comparison with MELD score, MELD-Na score, and Updated MELD score (all P < 0.001). Conclusion: The predictive value of creatinine for CAKI should be re-evaluated. AKI-MELD score is a potentially reliable tool to determine the prognosis for mortality of CAKI. (Hepatology Communications 2017;1:748-756).

The combination of indocyanine green clearance test and model for end-stage liver disease score predicts early graft outcome after liver transplantation

Early allograft dysfunction (EAD) and early postoperative complications are two important clinical endpoints when evaluating clinical outcomes of liver transplantation (LT). We developed and validated two ICGR15-MELD models in 87 liver transplant recipients for predicting EAD and early postoperative complications after LT by incorporating the quantitative liver function tests (ICGR15) into the MELD score. Eighty seven consecutive patients who underwent LT were collected and divided into a training cohort (n = 61) and an internal validation cohort (n = 26). For predicting EAD after LT, the area under curve (AUC) for ICGR15-MELD score was 0.876, with a sensitivity of 92.0% and a specificity of 75.0%, which is better than MELD score or ICGR15 alone. The recipients with a ICGR15-MELD score ≥0.243 have a higher incidence of EAD than those with a ICGR15-MELD score <0.243 (P <0.001). For predicting early postoperative complications, the AUC of ICGR15-MELD score was 0.832, with a sensitivity of 90.9% and a specificity of 71.0%. Those recipients with an ICGR15-MELD score ≥0.098 have a higher incidence of early postoperative complications than those with an ICGR15-MELD score <0.098 (P < 0.001). Finally, application of the two ICGR15-MELD models in the validation cohort still gave good accuracy (AUC, 0.835 and 0.826, respectively) in predicting EAD and early postoperative complications after LT. The combination of quantitative liver function tests (ICGR15) and the preoperative MELD score is a reliable and effective predictor of EAD and early postoperative complications after LT, which is better than MELD score or ICGR15 alone.

Effect of Early Everolimus-Facilitated Reduction of Tacrolimus on Efficacy and Renal Function in De Novo Liver Transplant Recipients: 24-Month Results for the North American Subpopulation

Background

A recent randomized phase III study of 719 de novo liver transplant recipients showed that early everolimus plus reduced-dose tacrolimus (EVR + rTAC) led to significantly better kidney function than standard TAC (TAC-C), without compromising efficacy. In that study, patients from North America (n = 211) had increased risk factors for posttransplant renal insufficiency at study start, relative to patients from Europe and rest of world (eg, worse renal function, more diabetes, older age).

Methods

A post hoc analysis was performed to assess whether these regional disparities affected study outcomes in North American patients.

Results

In this subpopulation, estimated glomerular filtration rates at randomization were higher in TAC-C over EVR + rTAC (76.4 vs 69.3 mL/min per 1.73 m²). Mean changes in estimated glomerular filtration rate values (mL/min per 1.73 m²) favored EVR + rTAC over TAC-C at months 12 (+3.7 vs −4.5; P = 0.032), 24 (+2.7 vs −6.6; P = 0.042), and 36 (+4.3 vs −8.1; P = 0.059). The composite efficacy endpoint of treated biopsy-proven acute rejection, graft loss, or death was 10.9%, 14.1%, and 14.1% for EVR + rTAC and 13.1%, 17.2%, and 19.3% for TAC-C at months 12, 24, and 36, respectively.

Conclusions

Although the North American cohort had more comorbidities, results were consistent with the overall population for efficacy and renal function.

In order to reduce nephrotoxicity in liver transplantation, several strategies are being explored including early everolimus-facilitated tacrolimus dose reduction, which in a recent multicenter study led to better kidney function versus standard TAC without compromising efficacy. In this North American cohort sub-analysis, results are similar despite higher baseline comorbidities.

Acute kidney injury after liver transplantation: Recent insights and future perspectives

Acute kidney injury (AKI) is a common postoperative complication after liver transplantation (LT). The occurrence of postoperative AKI after LT (Post-LT AKI) is associated with inferior patient and graft outcomes. Post-LT AKI is multifactorial in origin and has been related to the severity of liver disease, pre-LT renal dysfunction, graft quality, perioperative events and toxicity of immunosuppressive therapy. Furthermore it is thought that hepatic ischaemia reperfusion injury might be a driving force in the aetiology of post-LT AKI. Novel biomarkers for AKI are emerging and can be useful for early identification and characterization of AKI. There is a clear need for strategies aimed at preventing or treating post-LT AKI. Several pharmacological and non-pharmacological interventions have been studied, but so far failed to show any benefit in the prevention of post-LT AKI. Further studies are needed to develop and evaluate new interventions aimed at preventing post-LT AKI and improve patient outcomes.

Relationship Between Intraoperative Hypotension and Acute Kidney Injury After Living Donor Liver Transplantation: A Retrospective Analysis

OBJECTIVE

Acute kidney injury (AKI) is common after liver transplantation (LT) and has a significant impact on outcomes. Although several risk factors for post-LT AKI have been identified, the effect of intraoperative hemodynamic status on post-LT AKI remains unknown. Therefore, the authors aimed to investigate the relationship between hemodynamic parameters during LT and postoperative AKI.

DESIGN

A retrospective observational study.

SETTING

University hospital.

PARTICIPANTS

Patients who underwent living donor LT (n = 231).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Severe AKI (stages 2-3 according to recent guidelines) was the primary outcome. Multivariable logistic regression analysis was used to control for confounding variables to obtain the independent relationship between intraoperative hemodynamic parameters (mean arterial pressure [MAP] and cardiac index) and severe AKI. The prevalence of severe AKI was 30.7%. Nadir MAP during the surgery was independently predictive of severe AKI (adjusted odds ratio, 2.11 [95% confidence interval, 1.32-3.47] per 10-mmHg decrease; p = 0.002). Subgroup analyses based on various patient or operative variables and extensive sensitivity analyses showed substantially similar results. Severe hypotension (MAP<40 mmHg), even for fewer than 10 minutes, was related significantly to severe AKI (adjusted odds ratio, 3.80 [95% confidence interval, 1.17-12.30]; p = 0.026). In contrast, nadir cardiac index was not related significantly to severe AKI.

CONCLUSIONS

The authors found an independent relationship between degree of intraoperative hypotension and risk of severe AKI in living donor LT recipients. Severe hypotension, even for a short duration, was related significantly to severe AKI.

Utilizing electronic health records to predict acute kidney injury risk and outcomes: workgroup statements from the 15(th) ADQI Consensus Conference

The data contained within the electronic health record (EHR) is "big" from the standpoint of volume, velocity, and variety. These circumstances and the pervasive trend towards EHR adoption have sparked interest in applying big data predictive analytic techniques to EHR data. Acute kidney injury (AKI) is a condition well suited to prediction and risk forecasting; not only does the consensus definition for AKI allow temporal anchoring of events, but no treatments exist once AKI develops, underscoring the importance of early identification and prevention. The Acute Dialysis Quality Initiative (ADQI) convened a group of key opinion leaders and stakeholders to consider how best to approach AKI research and care in the "Big Data" era. This manuscript addresses the core elements of AKI risk prediction and outlines potential pathways and processes. We describe AKI prediction targets, feature selection, model development, and data display.

Model for end-stage liver disease score in the first 3 weeks after liver transplantation as a predictor for long-term outcome

BACKGROUND

Early allograft dysfunction after liver transplantation (LTX) is not well defined. The aim of this study was to evaluate the value of early post-transplant model for end-stage liver disease (MELD) scores for predicting long-term outcome after transplantation.

METHODS

In this single-center retrospective study, 362 consecutive patients after LTX were included. MELD scores at 7, 14, and 21 postoperative days (PODs) were calculated from primary lab values. Receiver operating characteristic (ROC) analyses were carried out to determine the critical cutoff MELD scores for patient and graft survival.

RESULTS

One year after transplantation, the patient and graft survival rates were 85 and 69%, respectively. Although pretransplant MELD scores were similar, they were significantly different at POD7, POD14, and POD21 between patients who died and those who survived the first year after transplantation. As shown by ROC curves, for patient survival, the optimal time point is POD14 with a cutoff MELD of 17. At this time point, patients with a MELD below 17 showed a 1-year survival rate of 94.3% and patients with a MELD of 17 and higher showed a 1-year survival rate of only 75.4%. For graft survival, the optimal time point was day 7 and a cutoff MELD of 29 (92% at MELD<29; 56.4% at MELD≥29). A multivariate analysis of potential risk factors indicated a significant role of serum bilirubin and MELD score determined on POD14 for patient survival.

CONCLUSION

In conclusion, early postoperative MELD scores predict outcome after LTX. The postoperative MELD score at POD14 is a good predictor for patient survival and at POD7 for the graft survival after LTX.

Evaluation of perioperative predictors of acute kidney injury post orthotopic liver transplantation

Acute kidney injury (AKI) is a common complication following orthotopic liver transplantation. It is associated with increased morbidity and mortality, as well as increased healthcare costs. The aetiology of AKI post liver transplantation is multifactorial and understanding these factors is pivotal in developing risk stratification and prevention strategies. This study aims to investigate the preoperative and intraoperative factors that may be associated with AKI in patients undergoing liver transplantation at the Princess Alexandra Hospital, Brisbane, Queensland. In our study, retrospective data of 97 consecutive orthotopic liver transplantations performed between January 2009 and August 2012 were recorded. Univariate and multivariate analyses were performed to investigate the preoperative and intraoperative risk factors for the development of AKI in this cohort. In the cohort of 97 patients who underwent orthotopic liver transplantation, 24 patients (25%) developed postoperative AKI. Univariate analysis demonstrated that high preoperative body mass index and intraoperative noradrenaline use were both associated with AKI. Multivariate analysis demonstrated that high body mass index, high Model for End-stage Liver Disease score and intraoperative noradrenaline use were associated with AKI. Overall mortaility was 4.1% during the study period and was not significantly different between the two groups. The high incidence of AKI following liver transplantation in this study cohort highlights the importance of this issue. This study has identified several potential pre- and intraoperative risk factors, providing a focus for patient surveillance and future research.

Acute Kidney Injury in the Surgical Patient

Perioperative acute kidney injury (AKI) is a common, morbid, and costly surgical complication. Current efforts to understand and manage AKI in surgical patients focus on prevention, mitigation of further injury when AKI has occurred, treatment of associated conditions, and facilitation of renal recovery. Lesser severity AKI is now understood to be much more common, and more morbid, than was previously thought. The ability to detect AKI within hours of onset would be helpful in protecting the kidney and in preserving renal function, and several imaging and biomarker modalities are currently being evaluated.

Clinical Risk Scoring Models for Prediction of Acute Kidney Injury after Living Donor Liver Transplantation: A Retrospective Observational Study

Acute kidney injury (AKI) is a frequent complication of liver transplantation and is associated with increased mortality. We identified the incidence and modifiable risk factors for AKI after living-donor liver transplantation (LDLT) and constructed risk scoring models for AKI prediction. We retrospectively reviewed 538 cases of LDLT. Multivariate logistic regression analysis was used to evaluate risk factors for the prediction of AKI as defined by the RIFLE criteria (RIFLE = risk, injury, failure, loss, end stage). Three risk scoring models were developed in the retrospective cohort by including all variables that were significant in univariate analysis, or variables that were significant in multivariate analysis by backward or forward stepwise variable selection. The risk models were validated by way of cross-validation. The incidence of AKI was 27.3% (147/538) and 6.3% (34/538) required postoperative renal replacement therapy. Independent risk factors for AKI by multivariate analysis of forward stepwise variable selection included: body-mass index >27.5 kg/m2 [odds ratio (OR) 2.46, 95% confidence interval (CI) 1.32-4.55], serum albumin <3.5 mg/dl (OR 1.76, 95%CI 1.05-2.94), MELD (model for end-stage liver disease) score >20 (OR 2.01, 95%CI 1.17-3.44), operation time >600 min (OR 1.81, 95%CI 1.07-3.06), warm ischemic time >40 min (OR 2.61, 95%CI 1.55-4.38), postreperfusion syndrome (OR 2.96, 95%CI 1.55-4.38), mean blood glucose during the day of surgery >150 mg/dl (OR 1.66, 95%CI 1.01-2.70), cryoprecipitate > 6 units (OR 4.96, 95%CI 2.84-8.64), blood loss/body weight >60 ml/kg (OR 4.05, 95%CI 2.28-7.21), and calcineurin inhibitor use without combined mycophenolate mofetil (OR 1.87, 95%CI 1.14-3.06). Our risk models performed better than did a previously reported score by Utsumi et al. in our study cohort. Doses of calcineurin inhibitor should be reduced by combined use of mycophenolate mofetil to decrease postoperative AKI. Prospective randomized trials are required to address whether artificial modification of hypoalbuminemia, hyperglycemia and postreperfusion syndrome would decrease postoperative AKI in LDLT.