Strong impact of acute kidney injury on survival after liver transplantation

MELD3.0 is superior to MELDNa and MELD for prediction of mortality in patients with cirrhosis: An external validation in a multi-ethnic population

Background and Aim

The model for end-stage liver disease (MELD) was updated to MELDNa and recently to MELD3.0 to predict survival of cirrhotic patients. We validated the prognostic performance of MELD3.0 and compared with MELDNa and MELD amongst cirrhotic inpatients.

Methods

Demographical, clinical, biochemical, and survival data of cirrhotic inpatients in Singapore General Hospital (SGH) from 01 January 2018 to 31 December 2018, were studied retrospectively. Patients were followed up from first admission in 2018 until death or until 01 April 2023. Area under the receiver operating characteristic curves (AUROC) were computed for the discriminative effects of MELD3.0, MELDNa, and MELD to predict 30-, 90-, and 365-day mortalities. AUROC was compared with DeLong's test. The cutoff MELD3.0 score for patients at high risk of 30-day mortality was determined using Youden's Index. Survival curves of patients with MELD3.0 score above and below the cutoff were estimated with Kaplan-Meier method and compared with log-rank analysis.

Results

Totally 862 patients were included (median age 71.0 years [interquartile range, IQR: 64.0-79.0], 65.4% males, 75.8% Chinese). Proportion of patients with Child-Turcotte-Pugh classes A/B/C were 55.5%/35.5%/9.0%. Median MELD3.0/MELDNa/MELD scores were 12.2 (IQR: 8.7-18.3)/11.0 (IQR: 8.0-17.5)/10.3 (IQR: 7.8-15.0). Median time of follow-up was 51.9 months (IQR: 8.5-59.6). The proportion of 30-/90-/365-day mortalities was 5.7%/13.2%/26.9%. AUROC of MELD3.0/MELDNa/MELD in predicting 30-, 90-, and 365-day mortalities, respectively, were 0.823/0.793/0.783, 0.754/0.724/0.707, 0.682/0.654/0.644 (P < 0.05). Optimal cutoff to predict 30-day mortality was MELD3.0 > 19 (sensitivity = 67.4%, specificity = 82.4%). Patients with MELD3.0 > 19, compared with patients with MELD3.0 ≤ 19, had shorter median time to death (98.0 days [IQR: 28.8-398.0] vs 390.0 days [IQR: 134.3-927.5]), and higher proportion of 30-day mortality (68.8% vs 43.0%) (P < 0.001).

Conclusion

MELD3.0 performs better than MELDNa and MELD in predicting mortality in cirrhotic inpatients. MELD3.0 > 19 predicts higher 30-day mortality.

Renal Replacement Therapy in Cirrhosis: A Contemporary Review

Acute kidney injury is a common complication of decompensated cirrhosis, frequently requires hospitalization, and carries a high short-term mortality. This population experiences several characteristic types of acute kidney injury: hypovolemic-mediated (prerenal), ischemic/nephrotoxic-mediated (acute-tubular necrosis), and hepatorenal syndrome. Prerenal acute kidney injury is treated with volume resuscitation. Acute-tubular necrosis is treated by optimizing perfusion pressure and discontinuing the offending agent. Hepatorenal syndrome, a unique physiology of decreased effective arterial circulation leading to renal vasoconstriction and ultimately acute kidney injury, is treated with plasma expansion with albumin and splanchnic vasoconstrictors such as terlipressin or norepinephrine. Common acute stressors such as bleeding, infection, and volume depletion often contribute to multifactorial acute kidney injury. Even with optimal medical management, many clinicians are faced with the challenge of initiating renal replacement therapy in these patients. This article reviews the epidemiology, indications, and complex considerations of renal replacement therapy for acute kidney injury in decompensated cirrhosis.

Impact of Sirolimus versus Mycophenolate Mofetil on Kidney Function after Calcineurin Inhibitor Dose Reduction in Liver Transplant Recipients

Impaired kidney function is associated with increased morbidity and mortality in patients undergoing liver transplantation. Although immunosuppressants are essential in these patients, they impair kidney function. This study aimed to compare adverse kidney outcomes between patients treated with a reduced dose of tacrolimus (calcineurin inhibitor) plus sirolimus or mycophenolate mofetil (MMF) in the liver transplant center at Kaohsiung Chang Gung Memorial Hospital between April 2011 and December 2017. Propensity score matching was used to identify 232 patients. The risk of adverse kidney outcomes was estimated using Cox proportional hazards regression, and changes in kidney function over time were analyzed using linear mixed modeling. Acute kidney disease risks in this study cohort were not significantly different for the two immunosuppressants (aHR 1.04; 95% CI: 0.70-1.55, p = 0.8328). However, sirolimus use was significantly associated with a higher risk of estimated glomerular filtration rate decline > 30% than MMF (aHR, 2.09; 95% CI: 1.33-3.28; p = 0.0014). Our results demonstrate that sirolimus use may have worsened long-term kidney outcomes compared to MMF. Close monitoring of kidney function, dose adjustment, and timely transition to MMF is necessary for LT patients receiving sirolimus.

The effects of bicarbonated versus acetated Ringer's solutions on acid-base status and kidney injury following orthotopic liver transplantation: Protocol for a single-centre, randomised controlled trial (The BETTER trial)

BACKGROUND

The ideal crystalloid fluid of choice for fluid therapy during liver transplantation is unknown. Conventional balanced crystalloids are buffered with organic anions, which requires liver metabolism to prevent matabolic acidosis and protect renal function. Therefore they can not function properly during liver transplantation. On the contrary, the bicarbonated Ringer's solution (BRS) can maintain acid-base status regardless of liver function. In this study, we aimed to test the hypothesis that, in patients undergoing orthotopic liver transplantation, compared with acetated Ringer's solutions (ARS), perioperative fluid therapy with BRS could better maintain the acid-base status.

METHODS

This is a prospective, single-centre, randomised controlled trial. 72 eligible patients will be randomised to receive either BRS or ARS perioperatively. The primary endpoint is the difference in standard base excess (SBE) before and after operation. Secondary endpoints include the incidence of acute kidney injury (AKI) within 48 h post operation and free and alive days to day 14 for intensive care admission, invasive ventilation, vasopressors, and renal replacement therapy (RRT).

DISCUSSION

Metabolic acidosis is common perioperatively, potentially leading to decreased renal blood flow and reduced glomerular filtration rate. The use of balanced solutions can prevent hyperchloremic metabolic acidosis, thereby avoiding AKI in some patients. However, during liver transplantation, when well-functioning liver metabolism is lacking, the organic anions in conventional balanced solutions may remain strong anions and thus fail to maintain the acid-base status, but no solid clinical evidence exists now. This study will, for the first time, provide evidence on the relative effects of BRS vs. ARS on acid-base status and renal injury in patients undergoing liver transplantation.

CLINICAL TRIAL REGISTRATION

The trial has been registered at the Chinese Clinical Trials Registry (ChiCTR2100046889) on 29 May 2021.

[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.

Protocol for a prospective double-blind, randomised, placebo-controlled feasibility trial of octreotide infusion during liver transplantation

INTRODUCTION

Liver transplantation is a complex operation that can provide significant improvements in quality of life and survival to the recipients. However, serious complications are common and include major haemorrhage, hypotension and renal failure. Blood transfusion and the development of acute kidney injury lead to both short-term and long-term poor patient outcomes, including an increased risk of death, graft failure, length of stay and reduced quality of life. Octreotide may reduce the incidence of renal dysfunction, perioperative haemorrhage and enhance intraoperative blood pressure. However, octreotide does have risks, including resistant bradycardia, hyperglycaemia and hypoglycaemia and QT prolongation. Hence, a randomised controlled trial of octreotide during liver transplantation is needed to determine the cost-efficacy and safety of its use; this study represents a feasibility study prior to this trial.

METHODS AND ANALYSIS

We describe a multicentre, double-blind, randomised, placebo-controlled feasibility study of continuous infusion of octreotide during liver transplantation surgery. We will recruit 30 adult patients at two liver transplant centres. A blinded infusion during surgery will be administered in a 2:1 ratio of octreotide:placebo. The primary outcomes will determine the feasibility of this study design. These include the recruitment ratio, correct administration of blinded study intervention, adverse event rates, patient and clinician enrolment refusal and completion of data collection. Secondary outcome measures of efficacy and safety will help shape future trials by assessing potential primary outcome measures and monitoring safety end points. No formal statistical tests are planned. This manuscript represents study protocol number 1.3, dated 2 June 2021.

ETHICS AND DISSEMINATION

This study has received Research Ethics Committee approval. The main study outcomes will be submitted to an open-access journal.

TRIAL SPONSOR

The Joint Research Office, University College London, UK.Neither the sponsor nor the funder have any role in study design, collection, management, analysis and interpretation of data, writing of the study report or the decision to submit the report for publication.

TRIAL REGISTRATION

The study is registered with ClinicalTrials.gov (NCT04941911) with recruitment due to start in August 2021 with anticipated completion in July 2022.

CLINICAL TRIALS UNIT

Surgical and Interventional Group, Division of Surgery & Interventional Science, University College London.

Acute Kidney Injury After Liver Transplant: Incidence, Risk Factors, and Impact on Patient Outcomes

OBJECTIVES

Acute kidney injury is a frequent complication of liver transplant. Here, we assessed the rate and contributing factors of acute kidney injury and need for renal replacement therapy in patients undergoing liver transplant at a transplant center in Tehran, Iran.

MATERIAL AND METHODS

We identified all patients who underwent liver transplant at the Imam Khomeini Hospital Complex from March 2018 to March 2019 and who were followed for 3 months after transplant. Acute kidney injury was defined based on the Acute Kidney Injury Network criteria. We collected demographic and pretransplant, intraoperative, and posttransplant data. Univariable and multivariable models were applied to explore independent risk factors for acute kidney injury incidence and need for renal replacement therapy.

RESULTS

Our study included 173 deceased donor liver transplant recipients. Rates of incidence of acute kidney injury and need for renal replacement therapy were 68.2% and 14.5%, respectively. The 3-month mortality rate among those with severe and mild or moderate acute kidney injury was 44.0% (14/25) and 9.7% (9/ 93), respectively (P < .001). Multivariable analyses indicated that serum albumin (relative risk of 0.55; 95% confidence interval, 0.34-0.87; P = .021), baseline serum creatinine (relative risk of 2.11; 95% confidence interval, 1.56-2.90; P = .037), and intraoperative mean arterial pressure (relative risk of 0.76; 95% confidence interval, 0.63-0.82; P = .008) were independent factors for predicting posttransplant acute kidney injury. Independent risk factors for requiring renal replacement therapy were pretransplant serum creatinine (relative risk of 1.99; 95% confidence interval, 1.89-4.47; P = .044) and intraoperative vasopressor infusion (relative risk of 1.41; 95% confidence interval, 1.38-2.00; P = .021).

CONCLUSIONS

We found a high incidence of acute kidney injury among liver transplant recipients in our center. There was a significant association between severity of acute kidney injury and 3-month and in-hospital mortality.

Impact of postoperative acute kidney injury in patients undergoing major gastrointestinal surgery on 1-year survival and renal outcomes: a national multicentre cohort study

Background

The intermediate-term impact of acute kidney injury (AKI) in patients after major gastrointestinal and liver surgery has not been well characterized. This study aimed to evaluate the 1-year mortality rate and renal outcomes associated with postoperative AKI in a national prospective cohort.

Methods

This prospective multicentre, observational cohort with 1-year postoperative follow-up included adults undergoing major gastrointestinal and liver surgery across the UK and Ireland between 23 September and 18 November 2015. AKI was defined according to Kidney Disease Improving Global Outcomes (KDIGO) criteria. The primary outcome was death at 1-year after surgery, and the secondary outcome was Major Adverse Kidney Events (MAKE-365). Cox proportionate and multilevel logistic regression were used to account for case mix.

Results

Of 5745 patients across 173 centres, 1-year follow-up data was completed for 3504 patients (62.2 per cent, 126 centres), with attrition largely explained by centre non-participation (63.1 per cent). Some 13.6 per cent (475 of 3504) patients developed AKI by 7 days after surgery (stage 1: 9.2 per cent; stage 2/3: 4.3 per cent). At 1 year, 10.8 per cent (378 patients) experienced a MAKE-365 endpoint (303 patients had died, 61 had renal replacement therapy and 78 had renal dysfunction). Patients who experienced AKI by 7 days after surgery had a higher hazard of death at 1 year for KDIGO stage 1 (hazard ratio 1.50 (95 per cent c.i. 1.08 to 2.08), P = 0.016) and KDIGO stage 2/3 (hazard ratio 2.96 (95 per cent c.i. 2.02 to 4.33), P < 0.001). Both KDIGO stage 1 (odds ratio 2.09 (95 per cent c.i. 1.50 to 2.92), P < 0.001) and stage 2/3 (odds ratio 9.26 (95 per cent c.i. 6.31 to 13.59), P < 0.001) AKI were independently associated with MAKE-365.

Conclusion

AKI events within 7 days after gastrointestinal or liver surgery are associated with significantly worse survival and renal outcomes at 1 year.

Post-Liver Transplant Acute Kidney Injury

Acute kidney injury (AKI) is a common condition following liver transplantation (LT). It negatively impacts patient outcomes by increasing the chances of developing chronic kidney disease and reducing graft and patient survival rates. Multiple definitions of AKI have been proposed and used throughout the years, with the International Club of Ascites definition being the most widely now used for patients with cirrhosis. Multiple factors are associated with the development of post-LT AKI and can be categorized into pre-LT comorbidities, donor and recipient characteristics, operative factors, and post-LT factors. Many of these factors can be optimized in an attempt to minimize the risk of AKI occurring and to improve renal function if AKI is already present. A special consideration during the post-LT phase is needed for immunosuppression as certain immunosuppressive medications can be nephrotoxic. The calcineurin inhibitor tacrolimus (TAC) is the mainstay of immunosuppression but can result in AKI. Several strategies including use of the monoclonoal antibody basilixamab to allow for delayed initiation of tacrolimus therapy and minimization through combination and minimization or elimination of TAC through combination with mycophenolate mofetil or mammalian target of rapamycin inhibitors have been implemented to reverse and avoid AKI in the post-LT setting. Renal replacement therapy may ultimately be required to support patients until recovery of AKI after LT. Overall, by improving renal function in post-LT patients with AKI, outcomes can be improved.

Acute kidney injury after liver transplantation, perioperative risk factors, and outcome: prospective observational study of 1681 patients (OLTx Study)

BACKGROUND

Acute kidney injury (AKI) represents a frequent complication after orthotopic liver transplantation (OLT). This study aimed to evaluate early postoperative AKI incidence during the first 72 h after OLT, perioperative risk factors, and AKI impact on survival.

METHODS

From January 2011 to December 2013) 1681 patients underwent OLT in 19 centers and were enrolled in this prospective cohort study.

RESULTS

According to RIFLE criteria, AKI occurred in 367 patients, 21.8% (R: 5.8%, I: 6.4%, F: 4.8%, L: 4.8%). Based on multivariate analysis, intraoperative risk factors for AKI were: administration of 5-10 RBCs (OR 1.8, 95%CI 1.3-2.7), dopamine use (OR 1.6, 95%CI 1.2-2.3), post-reperfusion syndrome (OR 1.5, 95%CI 1.0-2.3), surgical complications (OR 2.0, 95% CI 1.3-3.0), and cardiological complications (OR 2.2, 95%CI 1.2-4.0). Postoperative risk factors were: norepinephrine (OR 1.4, 95%CI 1.0-2.0), furosemide (OR 4.2, 95% CI 3.0-5.9), more than 10 RBCs transfusion, (OR 3.7, 95%CI 1.4-10.5), platelets administration (OR 1.6, 95% CI 1.1-2.4), fibrinogen administration (OR 3.0, 95%CI, 1.5-6.2), hepatic complications (OR 4.6, 95%CI 2.9-7.5), neurological complications (OR 2.4, 95%CI 1.5-3.7), and infectious complications (OR 2.7, 95%CI 1.8-4.3). NO-AKI patients' 5 years survival rate was higher than AKI patients (68.06, 95% CI 62.7-72.7 and 81.2, 95% CI 78.9-83.3, p< 0.001).

CONCLUSIONS

AKI still remains an important risk factor for morbidity and mortality after OLT. Further researches to develop new strategies aimed at preventing or minimizing post-OLT AKI are needed.

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.

Peri-operative risk factors of chronic kidney disease after liver transplantation

BACKGROUND

Chronic kidney disease (CKD) is a frequent long-term complication after liver transplantation (LT) and is associated with poor long-term survival. The aim of our study was to identify the risk factors of developing post-transplant CKD at 1 year, during the pre-operative, peri-operative, and post-LT phases.

METHODS

All consecutive patients who underwent primary LT between July 2013 and February 2018 were analyzed. To assess the impact of peri- and post-operative factors on renal function at 1 year we performed a propensity score matching on gender, age of the recipient, Model for End-Stage Liver Disease (MELD) score, etiology of the hepatic disease, and estimated Glomerular Filtration Rate (eGFR) at baseline.

RESULTS

Among the 245 patients who underwent LT, 215 had available data at one year (Y1), and 46% of them had CKD. Eighty-three patients in the CKD group and 83 in the normal renal function group were then matched. The median follow-up was 35 months (27-77). Patients with CKD at Y1 had a decreased 5-year survival compared to patients with normal renal function at one year: figures were 62% and 90%, respectively, p = 0.001. The independent predictors of CKD at Y1 were major complications (OR = 2.2, 95% CI [1.2-4.2]), p = 0.015, intensive care unit (ICU) stay > 5 days (OR = 2.2, 95% CI [1.3-5.1]), p = 0.046, ICU serum lactate level at 24 h ≥ 2.5 mmol/L (OR = 3.8 95% CI [1.1-8]), p = 0.034, need for post-LT renal replacement therapy (OR = 6.4 95% CI [1.4-25]), and MELD score ≥ 20 (OR = 2.1 95% CI [1.1-3.9]), p = 0.019.

CONCLUSIONS

The peri-operative period has a major impact on CKD incidence. Early recognition of patients at high risk of CKD may be critical for implementation of nephroprotective measures.

Long-Term Follow-Up of Renal Function in Children after Liver Transplantation-A Single Center Retrospective Study

Chronic kidney disease (CKD) is a common complication after liver transplantation (LT). Its prevalence with modern immunosuppression regimens, especially in children, is variable depending on the transplantation era. The study included 61 pediatric patients with at least 10 years of follow-up after liver transplantation remaining under constant care of the Department of Pediatric Surgery and Organ Transplantation. The analysis included several tests: estimated glomerular function (eGFR), results of screening for renal tubular defects and blood concentrations of basic immunosuppressive drug-tacrolimus. CKD was diagnosed in 3% of children at 12 years after LT. The maintaining of tacrolimus concentrations >4 ng/mL in long-term observation was associated with a significant increase of microalbuminuria. The presence of microalbuminuria, regarded as a risk factor of CKD, confirmed the necessity of regular comprehensive assessment of patients in long-term follow-up.

Hepatocellular carcinoma in patients with renal dysfunction: Pathophysiology, prognosis, and treatment challenges

The population of patients with hepatocellular carcinoma (HCC) overlaps to a high degree with those for chronic kidney disease (CKD) and end-stage renal disease (ESRD). The degrees of renal dysfunction vary, from the various stages of CKD to dialysis-dependent ESRD, which often affects the prognosis and treatment choice of patients with HCC. In addition, renal dysfunction makes treatment more difficult and may negatively affect treatment outcomes. This study summarized the possible causes of the high comorbidity of HCC and renal dysfunction. The possible mechanisms of CKD causing HCC involve uremia itself, long-term dialysis status, immunosuppressive agents for postrenal transplant status, and miscellaneous factors such as hormone alterations and dysbiosis. The possible mechanisms of HCC affecting renal function include direct tumor invasion and hepatorenal syndrome. Finally, we categorized the risk factors that could lead to both HCC and CKD into four categories: Environmental toxins, viral hepatitis, metabolic syndrome, and vasoactive factors. Both CKD and ESRD have been reported to negatively affect HCC prognosis, but more research is warranted to confirm this. Furthermore, ESRD status itself ought not to prevent patients receiving aggressive treatments. This study then adopted the well-known Barcelona Clinic Liver Cancer guidelines as a framework to discuss the indicators for each stage of HCC treatment, treatment-related adverse renal effects, and concerns that are specific to patients with pre-existing renal dysfunction when undergoing aggressive treatments against CKD and ESRD. Such aggressive treatments include liver resection, simultaneous liver kidney transplantation, radiofrequency ablation, and transarterial chemoembolization. Finally, focusing on patients unable to receive active treatment, this study compiled information on the latest systemic pharmacological therapies, including targeted and immunotherapeutic drugs. Based on available clinical studies and Food and Drug Administration labels, this study details the drug indications, side effects, and dose adjustments for patients with renal dysfunction. It also provides a comprehensive review of information on HCC patients with renal dysfunction from disease onset to treatment.

Perioperative ABO Blood Group Isoagglutinin Titer and the Risk of Acute Kidney Injury after ABO-Incompatible Living Donor Liver Transplantation

For ABO-incompatible liver transplantation (ABO-i LT), therapeutic plasma exchange (TPE) is performed preoperatively to reduce the isoagglutinin titer of anti-ABO blood type antibodies. We evaluated whether perioperative high isoagglutinin titer is associated with postoperative risk of acute kidney injury (AKI). In 130 cases of ABO-i LT, we collected immunoglobulin (Ig) G and Ig M isoagglutinin titers of baseline, pre-LT, and postoperative peak values. These values were compared between the patients with and without postoperative AKI. Multivariable logistic regression analysis was used to evaluate the association between perioperative isoagglutinin titers and postoperative AKI. Clinical and graft-related outcomes were compared between high and low baseline and postoperative peak isoagglutinin groups. The incidence of AKI was 42.3%. Preoperative baseline and postoperative peak isoagglutinin titers of both Ig M and Ig G were significantly higher in the patients with AKI than those without AKI. Multivariable logistic regression analysis showed that preoperative baseline and postoperative peak Ig M isoagglutinin titers were significantly associated with the risk of AKI (baseline: odds ratio 1.06, 95% confidence interval 1.02 to 1.09; postoperative peak: odds ratio 1.08, 95% confidence interval 1.04 to 1.13). Cubic spline function curves show a positive relationship between the baseline and postoperative peak isoagglutinin titers and the risk of AKI. Clinical outcomes other than AKI were not significantly different according to the baseline and postoperative peak isoagglutinin titers. Preoperative high initial and postoperative peak Ig M isoagglutinin titers were significantly associated with the development of AKI. As the causal relationship between high isoagglutinin titers and risk of AKI is unclear, the high baseline and postoperative isoagglutinin titers could be used simply as a warning sign for the risk of AKI after liver transplantation.

Doppler-derived renal resistive index helps predict acute kidney injury in patients undergoing living-related liver transplantation

BACKGROUND

Acute kidney injury (AKI) is commonly associated with increased postoperative morbidity in liver transplant (LT) recipients. The aim of this study was to identify the role of renal resistive index (RRI) in predicting AKI and to study the factors associated with AKI in LT recipients.

PATIENTS AND METHODS

We performed a single-center, prospective study, including adult living donor LT recipients at our center between January 2018 and September 2019 with no preoperative renal dysfunction. RRI was calculated on ultrasound doppler once preoperatively, and once daily in the postoperative period through postoperative day (POD) six. Patients were grouped into AKI and non-AKI groups for comparison.

RESULTS

Fifty patients were included in the study (mean age, 44 years; 20% females). AKI developed in 25 patients (50%). Both groups were similar in baseline characteristics. RRI of ≥ 0.69 on POD 2 predicted AKI (sensitivity 88%; specificity 92%). RRI on the day before AKI diagnosis (0.71 vs. 0.65) and on the day of diagnosis (0.72 vs. 0.65) were significantly increased relative to preoperative baseline.

CONCLUSIONS

Doppler-derived RRI is a rapid, non-invasive, and bedside procedure capable of predicting the occurrence of postoperative AKI in LT recipients.

Kidney Function After Liver Transplantation in a Single Center

Background

Renal dysfunction in the peri-transplant period appears to complicate both short- and long-term outcome of liver transplantation (LT). The aim of this study was to analyze the impact of selected clinical features in the peri-liver transplant period, as well calcineurin inhibitor, particularly tacrolimus given after LT, on kidney function in a single liver transplant center’s experience.

Material/Methods

A total 125 consecutive liver-grafted individuals (82 M, 43 F), mean age 50±13 y (with alcohol-related liver disease in 48 (38%) patients) were included into the study. Their clinical data were collected in the database until 46 months of follow-up, and the Python packages Pandas (version 0.22.0) and scikit-learn (version 0.21.3) were used for data analysis.

Results

More advanced liver disease as judged by Child-Pugh class and MELD score differed significantly patients with preserved (serum creatinine SCr <1.5 mg/dL) and impaired (SCr ≥1.5 mg/dL) kidney function before LT. Older age and higher SCr pre-LT were associated with higher levels of SCr after LT in 2 time-points. SCr before LT was correlated with delta SCr for the highest and last recorded value (P<0.0001). Higher amounts of transfused colloids during surgery were associated with increased delta SCr for the highest value (P=0.019) after grafting in logistic regression analysis. There were no associations between SCr after LT and duration of anhepatic phase, urine output ≤100 mL/h, or post-reperfusion syndrome during transplantation (all P>0.05). There were no associations between SCr after LT and tacrolimus trough levels in analyses of correlations and linear regression analyses (all P>0.05).

Conclusions

We found that pretransplant serum creatinine was the only factor affecting kidney function after LT in our liver transplant center. The restricted fluid policy was safe and effective in terms of long-term renal function. The role of kidney-saving immunosuppressive protocols in preserving renal function long-term after LT was also confirmed.

Delayed Calcineurin Inhibitor Introduction Without Antibody Induction in Liver Transplantation Is Safe and Helps Preserve Kidney Function

INTRODUCTION

Acute kidney injury (AKI) is common after liver transplantation and affects outcome after liver transplantation. Antibody induction is commonly used to reduce dose and/or to delay introduction of calcineurin inhibitor (CNI) but is very expensive. We propose a modified immunosuppressive protocol that delays administration of CNI for 48 to 72 hours without antibody induction. This study evaluates the results of our new protocol.

MATERIAL AND METHODS

A retrospective case-control study was performed. Study patients had induction with steroid and mycophenolate mofetil without antibody induction, and CNI administration was delayed for 48 to 72 hours. Control patients received CNI and steroid induction without antibody induction, and CNI was continued posttransplant. AKI was defined as an increase in serum creatinine level of at least 1.5 times the pretransplant baseline within the first postoperative week.

RESULTS

Sixty liver transplant recipients from 2013 to 2015 were included in this study (30 in the delayed CNI group and 30 in the control group). The patient characteristics and intraoperative factors were comparable in both groups. AKI developed in 11 patients in the study group and in 20 patients in the control group (37% vs 66.7%; P = .02). There was no acute rejection observed in the first month in either group.

CONCLUSION

We have demonstrated that delayed CNI introduction without antibody induction is safe and helps preserve kidney function. Antibody induction can be omitted safely in a delayed CNI introduction protocol to reduce the cost of liver transplantation without increasing the risk of acute rejection.

Clinical significance of personalized tacrolimus dosing by adjusting to donor CYP3A-status in liver transplant recipients

Donor's CYP3A-status (CYP3A5 genotype and CYP3A4 expression) can provide prognostic information regarding tacrolimus-metabolizing capacity of the liver graft and initial tacrolimus dosing for therapeutic blood concentrations in liver transplants. The present work prospectively investigated whether CYP3A-status guided tacrolimus therapy has any potential clinical benefit for recipients in the early postoperative period.

METHODS

The contribution of preliminary assaying of donor CYP3A-status to the optimization of initial tacrolimus therapy and to the reduction of adverse events (acute rejection, infection, nephrotoxicity) was investigated in 112 liver transplant recipients (CYPtest group) comparing to 101 control patients on tacrolimus concentration guided therapy.

RESULTS

The time for achieving therapeutic tacrolimus concentration was significantly reduced, confirming potential benefit of initial tacrolimus therapy adjusted to donor's CYP3A-status over classical clinical practice of tacrolimus concentration guided treatment (4 vs 8 days, P < 0.0001). Acute rejection episodes (3.6 vs 23.8%, P < 0.0001) and tacrolimus induced nephrotoxicity (8 vs 27%, P = 0.0004) were less frequent in CYPtest group than in control patients, whereas occurrence of infectious disease was not influenced by tacrolimus dosing strategy (3.6 vs 5.9% in CYPtest and control groups, P > 0.05). Acute rejection was often accompanied with tacrolimus blood concentrations lower than 10 ng mL^-1 (20/24 of control and 2/4 of CYPtest patients), while nephrotoxicity was associated with high tacrolimus concentrations (>20 ng mL^-1 ) in the first week after transplantation (13/27 of control and 2/9 of CYPtest patients).

CONCLUSION

CYP3A-status guided therapy significantly improved the risk of misdosing induced early adverse effects (acute rejection, nephrotoxicity).

Trends and Outcomes in Simultaneous Liver and Kidney Transplantation in Australia and New Zealand

AIM

Rates of simultaneous liver and kidney transplantation (SLKT) have increased, but indications for SLKT remain poorly defined. Additional data are needed to determine which patients benefit from SLKT to best direct use of scarce donor kidneys.

METHODS

Data were extracted from the Australia and New Zealand Dialysis and Transplant Registry (ANZDATA) database for all SLKT performed until the end of 2017. Patients were divided by pretransplant dialysis status into no dialysis before SLKT (preemptive kidney transplant) and any dialysis before SLKT (nonpreemptive). Baseline characteristics and outcomes were compared.

RESULTS

Between 1989 and 2017, inclusive, 84 SLKT procedures were performed in Australia, of which 24% were preemptive. Preemptive and nonpreemptive SLKT recipients did not significantly differ in age (P = .267), sex (P = .526), or ethnicity (P = .870). Over a median follow-up time of 4.5 years, preemptively transplanted patients had a statistically equivalent risk of kidney graft failure (hazard ratio (HR) 1.83, 95% confidence interval [CI]: 0.36-12.86, P = .474) and all-cause mortality (HR 1.69, 95% CI: 0.51-5.6, P = .226) compared to nonpreemptive patients. Overall, 1- and 5-year survival rates for all SLKTs were 92% (95% CI: 86-96) and 60% (95% CI: 45-75), respectively.

CONCLUSION

Kidney graft and overall patient survival were similar between patients with preemptive kidney transplant and those who were dialysis dependent.

Intraoperative Hemodynamic Parameters and Acute Kidney Injury After Living Donor Liver Transplantation

BACKGROUND

Acute kidney injury (AKI) after living donor liver transplantation (LDLT) is associated with increased mortality. We sought to identify associations between intraoperative hemodynamic variables and postoperative AKI.

METHODS

We retrospectively reviewed 734 cases of LDLT. Intraoperative hemodynamic variables of systemic and pulmonary arterial pressure, central venous pressure (CVP), and pulmonary artery catheter-derived parameters including mixed venous oxygen saturation (SvO2), right ventricular end-diastolic volume (RVEDV), stroke volume, systemic vascular resistance, right ventricular ejection fraction, and stroke work index were collected. Propensity score matching analysis was performed between patients with (n = 265) and without (n = 265) postoperative AKI. Hemodynamic variables were compared between patients with AKI, defined by Kidney Disease Improving Global Outcomes criteria, and those without AKI in the matched sample.

RESULTS

The incidence of AKI was 36.1% (265/734). Baseline CVP, baseline RVEDV, and SvO2 at 5 minutes before reperfusion were significantly different between patients with and without AKI in the matched sample of 265 pairs. Multivariable logistic regression analysis revealed that baseline CVP, baseline RVEDV, and SvO2 at 5 minutes before reperfusion were independent predictors of AKI (CVP per 5 cm H2O increase: odds ratio [OR], 1.20; 95% confidence interval [CI], 1.09-1.32; SvO2: OR, 1.45; 95% CI, 1.27-1.71; RVEDV: OR, 1.48; 95% CI, 1.24-1.78).

CONCLUSIONS

The elevated baseline CVP, elevated baseline RVEDV after anesthesia induction, and decreased SvO2 during anhepatic phase were associated with postoperative AKI. Prospective trials are required to evaluate whether the optimization of these variables may decrease the risk of AKI after LDLT.

Incidence of chronic kidney disease after orthotopic liver transplantation in a Chinese cohort

BACKGROUND

Kidney dysfunction frequently occurred after orthotopic liver transplantation (OLT). Chronic renal disease (CKD) is a complicated problem and is associated with increased mortality. The aim of this study is to find the risk factors for the incidence of CKD at 1 year after OLT in China.

METHODS

From January 2017 to December 2017, we retrospectively assessed 280 recipients in our single center. Chronic renal failure was defined as estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m² for 3 months, regardless of the presence or absence of structural kidney damage. Cox proportional hazard model was used to identify the factors to the incidence of CKD after liver transplantations. Kaplan-Meier plots with log-rank test were presented to evaluate patient survival time in those with and without CKD.

RESULTS

With a median follow-up of 17.4 months, 48 patients developed CKD after liver transplantations, representing 17.1% of the cohort. The cox-regression model showed that recipients age (HR = 1.097, P < 0.01), AKI (HR = 1.542, P < 0.01) and MELD score (HR = 1.077, P < 0.01) were significantly associated with the development of post-transplant CKD at 1 year. Recipient survival at 1 year was significantly worse in recipients with CKD compared to those without CKD (P < 0.01) after adjustment by age and gender.

CONCLUSION

Our findings suggested that age, AKI and MELD score were associated with the incidence of CKD 1 year after OLT in a Chinese cohort. Recipients with CKD were associated with worse survival.

Protective Role of the Portocaval Shunt in Liver Transplantation

BACKGROUND

Advances in medical management and surgical technique have resulted in stepwise improvements in early post-transplant survival rates. Modifications in the surgical technique, such as the realization of the portocaval shunt (PCS), could influence survival rates. The aim of this study was to evaluate the mortality rate for 12 months after liver transplantation, analyzing the causes and risk factors related to its development and assessing the impact that PCS could have on them.

METHODS

A total of 231 recipients were included in the retrospective, longitudinal, and nonrandomized study.

RESULTS

The overall survival of the transplant was 85.2% (197 patients). The most frequent cause of death was infection (38.2%), followed by the multiorgan failure of multiple etiology (23.5%). Most of the risk factors related to mortality correspond to variables of the postoperative period. The results of the multivariate analysis identified the main risk factors for death: the presence of surgical complications and the need for renal replacement therapy. In contrast, the performance of PCS exerted a protective effect, reducing the probability of death by 70%.

CONCLUSIONS

Despite the good results obtained in several studies, there is still debate regarding the benefit of its realization. In our study, PCS was a factor associated with a reduction in mortality, with a markedly lower probability of adverse events. However, we agree with other authors on the need for larger and randomized studies to adequately determine the validity of such results.

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.

Acute kidney injury: A critical care perspective for orthotopic liver transplantation

Acute kidney injury (AKI) is associated with high perioperative mortality in patients undergoing liver transplantation (LT). In the era of Model of End-stage Liver Disease score-based allocation, more patients with impaired renal function are receiving LT. The majority of preoperative AKI is secondary to azotemia, including hepatorenal syndrome - a progressive form of renal impairment unique to liver failure. Prompt recognition and initiation of cause-directed therapies are central to improving post-transplant survival. Given that, the healthcare providers must develop an expertise in liver failure-related renal complications, specifically their management and perioperative implications. Notably, AKI may complicate intraoperative course, exacerbating hemodynamic instability, metabolic acidosis, and electrolyte and coagulation abnormalities. Adjunctive intraoperative continuous renal replacement therapy has been employed; however, prospective studies remain necessary to validate potential benefits.

Challenges of one-year longitudinal follow-up of a prospective, observational cohort study using an anonymised database: recommendations for trainee research collaboratives

BACKGROUND

Trainee research collaboratives (TRCs) have pioneered high quality, prospective 'snap-shot' surgical cohort studies in the UK. Outcomes After Kidney injury in Surgery (OAKS) was the first TRC cohort study to attempt to collect one-year follow-up data. The aims of this study were to evaluate one-year follow-up and data completion rates, and to identify factors associated with improved follow-up rates.

METHODS

In this multicentre study, patients undergoing major gastrointestinal surgery were prospectively identified and followed up at one-year following surgery for six clinical outcomes. The primary outcome for this report was the follow-up rate for mortality at 1 year. The secondary outcome was the data completeness rate in those patients who were followed-up. An electronic survey was disseminated to investigators to identify strategies associated with improved follow-up.

RESULTS

Of the 173 centres that collected baseline data, 126 centres registered to participate in one-year follow-up. Overall 62.3% (3482/5585) of patients were followed-up at 1 year; in centres registered to collect one-year outcomes, the follow-up rate was 82.6% (3482/4213). There were no differences in sex, comorbidity, operative urgency, or 7-day postoperative AKI rate between patients who were lost to follow-up and those who were successfully followed-up. In centres registered to collect one-year follow-up outcomes, overall data completeness was 83.1%, with 57.9% (73/126) of centres having ≥95% data completeness. Factors associated with increased likelihood of achieving ≥95% data completeness were total number of patients to be followed-up (77.4% in centres with < 15 patients, 59.0% with 15-29 patients, 51.4% with 30-59 patients, and 36.8% with > 60 patients, p = 0.030), and central versus local storage of patient identifiers (72.5% vs 48.0%, respectively, p = 0.006).

CONCLUSIONS

TRC methodology can be used to follow-up patients identified in prospective cohort studies at one-year. Follow-up rates are maximized by central storage of patient identifiers.

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.

Impact of early remote organ dysfunction on long-term survival after liver transplantation

BACKGROUND

Attention is focused on graft function although extrahepatic organ dysfunction often occurs. Renal failure, cardiovascular events and sepsis have individually shown a significant impact on short- and long-term outcomes. The aim of the study was to identify how extrahepatic organ dysfunction (EROD) and allograft dysfunction (EAD) may be associated and their relative impact on long-term survival.

METHODS

A retrospective study was conducted in a unicentric cohort of 294 patients transplanted between 2009 and 2014. The composite endpoint EROD was defined as requirement during the hospitalization of de novo renal replacement therapy, reintubation/ventilation > 7 days or cardiovascular event. Donor and recipient characteristics were evaluated as predictive of EROD in uni- and multivariate analysis. Main endpoint was overall survival evaluated by Kaplan-Meier method.

RESULTS

EROD occurred in 91 patients (31%) among whom 42 also experienced EAD (46%). Predicting factors associated with EROD were IL6 level (P = 0.002) and lab-MELD (P < 0.001). Only patients experiencing both EAD and EROD had a worse survival (P = 0.001). In patients without EAD, time to normalization of bilirubin and INR were longer in patients with EROD compared to those without EROD (P = 0.002 and P = 0.008 respectively).

CONCLUSIONS

The composite endpoint described as early remote organ dysfunction could be used as a predictive factor after transplantation and should be included in future studies together with early allograft dysfunction. Identifying patients in whom EROD and EAD occur together or one after the other could help to better predict long-term outcomes.

Influence of Transfusion on the Risk of Acute Kidney Injury: ABO-Compatible versus ABO-Incompatible Liver Transplantation

ABO-incompatible liver transplantation (ABO-i LT) is associated with a higher risk of acute kidney injury (AKI) compared to ABO-compatible liver transplantation (ABO-c LT). We compared the risk of AKI associated with transfusion between ABO-c and ABO-i living donor liver transplantation (LDLT). In 885 cases of LDLT, we used a propensity score analysis to match patients who underwent ABO-c (n = 766) and ABO-i (n = 119) LDLT. Baseline medical status, laboratory findings, and surgical- and anesthesia-related parameters were used as contributors for propensity score matching. AKI was defined according to the "Kidney Disease Improving Global Outcomes" criteria. After 1:2 propensity score matching, a conditional logistic regression analysis was performed to evaluate the relationship between the intraoperative transfusion of packed red blood cells (pRBCs) and fresh frozen plasma (FFP) on the risk of AKI. The incidence of AKI was higher in ABO-i LT than in ABO-c LT before and after matching (after matching, 65.8% in ABO-i vs 39.7% in ABO-c, p < 0.001). The incidence of AKI increased in direct proportion to the amount of transfusion, and this increase was more pronounced in ABO-i LT. The risk of pRBC transfusion for AKI was greater in ABO-i LT (multivariable adjusted odds ratio (OR) 1.32 per unit) than in ABO-c LT (OR 1.11 per unit). The risk of FFP transfusion was even greater in ABO-i LT (OR 1.44 per unit) than in ABO-c LT (OR 1.07 per unit). In conclusion, the association between transfusion and risk of AKI was stronger in patients with ABO-i LT than with ABO-c LT. Interventions to reduce perioperative transfusions may attenuate the risk of AKI in patients with ABO-i LT.

Transfusion of Older Red Blood Cells Increases the Risk of Acute Kidney Injury After Orthotopic Liver Transplantation: A Propensity Score Analysis

BACKGROUND

Acute kidney injury (AKI) is a common and serious complication of orthotopic liver transplantation (OLT). Transfusion of older red blood cells (RBCs) has been implicated in poor outcomes in trauma, cardiac surgery, and critically ill patients. However, whether transfusion of older RBCs plays any role in post-OLT AKI remained unknown. The aim of this study was to investigate the effect of the age of transfused RBCs on post-OLT AKI.

METHODS

The clinical data of consecutive adult patients who received donation after cardiac death and underwent OLT from December 2011 to December 2015 were analyzed. These patients were divided into 2 groups: the newer blood group, who received exclusively RBCs that had been stored for <14 days; and the older blood group, who received RBCs that had been stored for 14 days or more. The incidence of post-OLT AKI, severe AKI, lengths of intensive care unit and hospital stay, and in-hospital mortality after OLT were analyzed.

RESULTS

Postoperative AKI occurred in 65.1% of patients in the older blood group and 40.5% of patients in the newer blood group (P < .01). The incidence of severe AKI after OLT was significantly higher, and the duration of intensive care unit stay was significantly longer, in the older blood group. After adjustment by the multivariable regression logistic analysis, transfusion of older blood was independently associated with post-OLT AKI (odds ratio [OR] = 2.47 [95% confidence interval {CI}, 1.13-5.41]; P = .024) and severe AKI (OR = 5.88 [95% CI, 2.06-16.80]; P = .001). After adjustment by the inverse probability of treatment weighting analysis, patients in the older blood group still had significantly higher incidences of postoperative AKI (OR = 2.13 [95% CI, 1.07-4.22]; P = .030) and severe AKI (OR = 3.34 [95% CI, 1.47-7.60]; P = .003) than those in the newer blood group.

CONCLUSIONS

Transfusion of older RBCs significantly increased the risk of postoperative AKI in liver transplant recipients.

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.

Early Persistent Progressive Acute Kidney Injury and Graft Failure Post Liver Transplantation

Background

Acute kidney injury (AKI) in the setting of liver transplantation is a common and multifaceted complication. Studies in the general population have demonstrated worse prognosis with AKI episodes that persist for a longer duration. Our primary objective was to evaluate the impact of early AKI episodes that are persistent or progressive in nature, on patient outcomes and graft survival.

Methods

This was a retrospective cohort study including all patients who received a liver transplant between 2011 and 2015 at our center. Moderate to severe AKI episodes (AKIN II or III) were recorded immediately before transplantation and after surgery until hospital discharge. We evaluated the incidence density rate (IDR) of graft failure and the time to graft failure in patients with persistent or progressive AKI (ppAKI) as compared to controls.

Results

Two hundred seventy-nine patients received 301 deceased donor liver allografts. Progressive or persistent AKI was documented in more than half of transplant cases (152/301). The rate of graft loss was 3 times higher in the ppAKI group (25%) versus the controls (8.7%). The IDR of graft failure was 13.79 per 100 case-years in the ppAKI group as compared with 3.79 per 100 case-years in the controls (IDR ratio, 3.64; 95 % confidence interval, 1.88–7.50). After adjusting for hepatic artery thrombosis, ischemic cholangiopathy, infectious complications and Model for End-stage Liver Disease, ppAKI was associated with a decreased graft survival time.

Conclusions

Persistent or progressive AKI after liver transplantation is associated with an increased incidence rate of graft failure and is an independent predictor of decreased graft survival time.

Compliance with ethical standards in the reporting of donor sources and ethics review in peer-reviewed publications involving organ transplantation in China: a scoping review

OBJECTIVES

The objective of this study is to investigate whether papers reporting research on Chinese transplant recipients comply with international professional standards aimed at excluding publication of research that: (1) involves any biological material from executed prisoners; (2) lacks Institutional Review Board (IRB) approval and (3) lacks consent of donors.

DESIGN

Scoping review based on Arksey and O'Mallee's methodological framework.

DATA SOURCES

Medline, Scopus and Embase were searched from January 2000 to April 2017.

ELIGIBILITY CRITERIA

We included research papers published in peer-reviewed English-language journals reporting on outcomes of research involving recipients of transplanted hearts, livers or lungs in mainland China.

DATA EXTRACTION AND SYNTHESIS

Data were extracted by individual authors working independently following training and benchmarking. Descriptive statistics were compiled using Excel.

RESULTS

445 included studies reported on outcomes of 85 477 transplants. 412 (92.5%) failed to report whether or not organs were sourced from executed prisoners; and 439 (99%) failed to report that organ sources gave consent for transplantation. In contrast, 324 (73%) reported approval from an IRB. Of the papers claiming that no prisoners' organs were involved in the transplants, 19 of them involved 2688 transplants that took place prior to 2010, when there was no volunteer donor programme in China.

DISCUSSION

The transplant research community has failed to implement ethical standards banning publication of research using material from executed prisoners. As a result, a large body of unethical research now exists, raising issues of complicity and moral hazard to the extent that the transplant community uses and benefits from the results of this research. We call for retraction of this literature pending investigation of individual papers.

Intraoperative Oliguria with Decreased SvO₂ Predicts Acute Kidney Injury after Living Donor Liver Transplantation

Acute kidney injury (AKI) is a frequent complication after living donor liver transplantation (LDLT), and is associated with increased mortality. However, the association between intraoperative oliguria and the risk of AKI remains uncertain for LDLT. We sought to determine the association between intraoperative oliguria alone and oliguria coupled with hemodynamic derangement and the risk of AKI after LDLT. We evaluated the hemodynamic variables, including mean arterial pressure, cardiac index, and mixed venous oxygen saturation (SvO₂). We reviewed 583 adult patients without baseline renal dysfunction and who did not receive hydroxyethyl starch during surgery. AKI was defined using the Kidney Disease Improving Global Outcomes criteria according to the serum creatinine criteria. Multivariable logistic regression analysis was performed with and without oliguria and oliguria coupled with a decrease in SvO₂. The performance was compared with respect to the area under the receiver operating characteristic curve (AUC). Intraoperative oliguria <0.5 and <0.3 mL/kg/h were significantly associated with the risk of AKI; however, their performance in predicting AKI was poor. The AUC of single predictors increased significantly when oliguria was combined with decreased SvO₂ (AUC 0.72; 95% confidence interval (CI) 0.68–0.75 vs. AUC of oliguria alone 0.61; 95% CI 0.56–0.61; p < 0.0001; vs. AUC of SvO₂ alone 0.66; 95% CI 0.61–0.70; p < 0.0001). Addition of oliguria coupled with SvO₂ reduction also increased the AUC of multivariable prediction (AUC 0.87; 95% CI 0.84–0.90 vs. AUC with oliguria 0.73; 95% CI 0.69–0.77; p < 0.0001; vs. AUC with neither oliguria nor SvO₂ reduction 0.68; 95% CI 0.64–0.72; p < 0.0001). Intraoperative oliguria coupled with a decrease in SvO₂ may suggest the risk of AKI after LDLT more reliably than oliguria alone or decrease in SvO₂ alone. Intraoperative oliguria should be interpreted in conjunction with SvO₂ to predict AKI in patients with normal preoperative renal function and who did not receive hydroxyethyl starch during surgery.

Predictive Value of Serum Creatinine, Blood Urea Nitrogen, Uric Acid, and β2-Microglobulin in the Evaluation of Acute Kidney Injury after Orthotopic Liver Transplantation

Background

As a major complication after orthotopic liver transplantation (OLT), the occurrence of acute kidney injury (AKI) is frequently defined by serum creatinine (Cr); however, the accuracy of commonly used blood urea nitrogen (BUN), uric acid (UA), and β₂-microglobulin (β₂-MG) remains to be explored. This retrospective study compared the accuracy of these parameters for post-OLT AKI evaluation.

Methods

Patients who underwent OLT in three centers between July 2003 and December 2013 were enrolled. The postoperative AKI group was diagnosed by the Kidney Disease Improving Global Outcomes (KDIGO) criteria and classified by stage. Measurement data were analyzed using the t-test or Wilcoxon rank-sum test; enumerated data were analyzed using the Chi-square test or Fisher's exact test. Diagnostic reliability and predictive accuracy were evaluated using receiver operating characteristic (ROC) curve analysis.

Results

This study excluded 976 cases and analyzed 697 patients (578 men and 119 women); the post-OLT AKI incidence was 0.409. Compared with the no-AKI group, the AKI group showed very significant differences in Model for End-stage Liver Disease score (14.74 ± 9.91 vs. 11.07 ± 9.54, Z = 5.404; P < 0.001), hepatic encephalopathy (45 [15.8%] vs. 30 [7.3%], χ² = 12.699; P < 0.001), hemofiltration (28 [9.8%] vs. 0 [0.0%], χ² = 42.171; P < 0.001), and 28-day mortality (23 [8.1%] vs. 9 [2.2%], χ² = 13.323; P <0.001). Moreover, mean values of Cr, BUN, UA, and β₂-MG in the AKI group differed significantly at postoperative days 1, 3, and 7 (all P < 0.001). ROC curve area was 0.847 of Cr for the detection of AKI Stage 1 (sensitivity 80.1%, specificity 75.7%, cutoff value 88.23 μmol/L), 0.916 for Stage 2 (sensitivity 87.6%, specificity 82.6%, cutoff value 99.9 μmol/L), and 0.972 for Stage 3 (sensitivity 94.1%, specificity 88.2%, cutoff value 122.90 μmol/L).

Conclusion

The sensitivity and specificity of serum Cr might be a high-value indicator for the diagnosis and grading of post-OLT AKI.

Differential Simultaneous Liver and Kidney Transplant Benefit Based on Severity of Liver Damage at the Time of Transplantation

Background

We evaluated the concept of whether liver failure patients with a superimposed kidney injury receiving a simultaneous liver and kidney transplant (SLKT) have similar outcomes compared to patients with liver failure without a kidney injury receiving a liver transplantation (LT) alone.

Methods

Using data from the United Network of Organ Sharing (UNOS) database, patients were divided into five groups based on pre-transplant model for end-stage liver disease (MELD) scores and categorized as not having (serum creatinine (sCr) ≤ 1.5 mg/dL) or having (sCr > 1.5 mg/dL) renal dysfunction. Of 30,958 patients undergoing LT, 14,679 (47.5%) had renal dysfunction, and of those, 5,084 (16.4%) had dialysis.

Results

Survival in those (liver failure with renal dysfunction) receiving SLKT was significantly worse (P < 0.001) as compared to those with sCr < 1.5 mg/dL (liver failure only). The highest mortality rate observed was 21% in the 36+ MELD group with renal dysfunction with or without SLKT. In high MELD recipients (MELD > 30) with renal dysfunction, presence of renal dysfunction affects the outcome and SLKT does not improve survival. In low MELD recipients (16 - 20), presence of renal dysfunction at the time of transplantation does affect post-transplant survival, but survival is improved with SLKT.

Conclusions

SLKT improved 1-year survival only in low MELD (16 - 20) recipients but not in other groups. Performance of SLKT should be limited to patients where a benefit in survival and post-transplant outcomes can be demonstrated.

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.

Incidence and outcomes of acute kidney injury in patients with hepatocellular carcinoma after liver transplantation

PURPOSE

To describe the incidence and outcomes linked with acute kidney injury (AKI) after liver transplantation (LT) in hepatocellular carcinoma (HCC) patients.

METHODS

From January 2003 to February 2011, HCC patients undergoing LT were retrospectively enrolled. Patient with a glomerular filtration rate (GFR) <60 mL/min/1.73 m² was excluded. AKI was defined and classified according to the AKIN criteria.

RESULTS

Of the 566 eligible patients, AKI was found in 109 (19.26%) patients (stage I, 66 cases; stage II, 15 cases; and stage III, 28 cases). Risk factors for AKI were the long anhepatic time (OR = 3.59, P = 0.009) and prolonged duration of systolic blood pressure (SBP) < 90 mmHg (OR = 1.07, P < 0.0001). Post-LT AKI was an independent risk factor associated with 30-day mortality (HR = 4.05, P = 0.047). Complete recovery occurred in 84 (77.06%) of all AKI episodes within 1 month after operation, while 25 patients (22.94%) suffered from prolonged AKI. Patients with prolonged AKI had a poorer 1-year survival than those with transient AKI (40 vs 86.90%; P < 0.0001). Patients with severe AKI more often developed prolonged AKI. 13 patients (52%) of the prolonged AKI progressed to chronic kidney disease (CKD) defined as eGFR <60 mL/min/1.73 m² after 1 year post-operation.

CONCLUSIONS

Post-LT AKI is not an uncommon complication. Intra-operative hemodynamic instability is crucial in the development of post-LT AKI and deserves more attention. Most post-LT AKI is transient and reversible, while the prolonged form may predict a decrease survival.

Association of Preoperative Urinary Uromodulin with AKI after Cardiac Surgery

BACKGROUND AND OBJECTIVES

AKI is a serious complication after cardiac surgery. Although high urinary concentrations of the tubular protein uromodulin, a marker of tubular health, are associated with less AKI in animal models, its relationship in humans is unknown.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A post hoc analysis of a prospective cohort study of 218 adults undergoing on-pump cardiac surgery between 2004 and 2011 was conducted. Multivariable logistic and linear regression analyses were used to evaluate the associations of preoperative urinary uromodulin-to-creatinine ratio with postoperative AKI (defined as a rise in serum creatinine of >0.3 mg/dl or >1.5 times baseline); severe AKI (doubling of creatinine or need for dialysis) and peak postoperative serum creatinine over the first 72 hours.

RESULTS

Mean age was 68 years, 27% were women, 95% were white, and the median uromodulin-to-creatinine ratio was 10.0 μg/g. AKI developed in 64 (29%) patients. Lower urinary uromodulin-to-creatinine ratio was associated with higher odds for AKI (odds ratio, 1.49 per 1-SD lower uromodulin; 95% confidence interval, 1.04 to 2.13), which was marginally attenuated after multivariable adjustment (odds ratio, 1.43; 95% confidence interval, 0.99 to 2.07). The lowest uromodulin-to-creatinine ratio quartile was also associated with higher odds for AKI relative to the highest quartile (odds ratio, 2.94; 95% confidence interval, 1.19 to 7.26), which was slightly attenuated after multivariable adjustment (odds ratio, 2.43; 95% confidence interval, 0.91 to 6.48). A uromodulin-to-creatinine ratio below the median was associated with higher adjusted odds for severe AKI, although this did not reach statistical significance (odds ratio, 4.03; 95% confidence interval, 0.87 to 18.70). Each 1-SD lower uromodulin-to-creatinine ratio was associated with a higher adjusted mean peak serum creatinine (0.07 mg/dl per SD; 95% confidence interval, 0.02 to 0.13).

CONCLUSIONS

Lower uromodulin-to-creatinine ratio is associated with higher odds of AKI and higher peak serum creatinine after cardiac surgery. Additional studies are needed to confirm these preliminary results.

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.

Acute kidney injury following liver transplantation: a systematic review of published predictive models

Acute kidney injury is a frequent postoperative complication amongst liver transplant recipients and is associated with increased morbidity and mortality. This systematic review analysed the existing predictive models, in order to solidify current understanding. Articles were selected for inclusion if they described the primary development of a clinical prediction model (either an algorithm or risk score) to predict AKI post liver transplantation. The database search yielded a total of seven studies describing the primary development of a prediction model or risk score for the development of AKI following liver transplantation. The models span thirteen years of clinical research and highlight a gradual change in the definitions of AKI, emphasising the need to employ standardised definitions for subsequent studies. Collectively, the models identify a diverse range of predictive factors with several common trends. They emphasise the impact of preoperative renal dysfunction, liver disease severity and aetiology, metabolic risk factors as well as intraoperative variables including measures of haemodynamic instability and graft quality. Although several of the models address postoperative parameters, their utility in predictive modelling seems to be of questionable relevance. The common risk factors identified within this systematic review provide a minimum list of variables, which future studies should address. Research in this area would benefit from prospective, multi-site studies with larger cohorts as well as the subsequent internal and external validation of predictive models. Ultimately, the ability to identify patients at high risk of post-transplant AKI may enable early intervention and perhaps prevention.

Incidence and risk factors for early renal dysfunction after liver transplantation

AIM: To determine renal dysfunction post liver transplantation, its incidence and risk factors in patients from a Belgian University Hospital.

METHODS: Orthotopic liver transplantations performed from January 2006 until September 2012 were retrospectively reviewed (n = 187). Patients with no renal replacement therapy (RRT) before transplantation were classified into four groups according to their highest creatinine plasma level during the first postoperative week. The first group had a peak creatinine level below 12 mg/L, the second group between 12 and 20 mg/L, the third group between 20 and 35 mg/L, and the fourth above 35 mg/L. In addition, patients who needed RRT during the first week after transplantation were also classified into the fourth group. Perioperative parameters were recorded as risk factors, namely age, sex, body mass index (BMI), length of preoperative hospital stay, prior bacterial infection within one month, preoperative ascites, preoperative treatment with β-blocker, angiotensin-converting enzyme inhibitor or non steroidal anti-inflammatory drugs, preoperative creatinine and bilirubin levels, donor status (cardiac death or brain death), postoperative lactate level, need for intraoperative vasopressive drugs, surgical revision, mechanical ventilation for more than 24 h, postoperative bilirubin and transaminase peak levels, postoperative hemoglobin level, amount of perioperative blood transfusions and type of immunosuppression. Univariate and multivariate analysis were performed using logistic ordinal regression method. Post hoc analysis of the hemostatic agent used was also done.

RESULTS: There were 78 patients in group 1 (41.7%), 46 in group 2 (24.6%), 38 in group 3 (20.3%) and 25 in group 4 (13.4%). Twenty patients required RRT: 13 (7%) during the first week after transplantation. Using univariate analysis, the severity of renal dysfunction was correlated with presence of ascites and prior bacterial infection, preoperative bilirubin, urea and creatinine level, need for surgical revision, use of vasopressor, postoperative mechanical ventilation, postoperative bilirubin and urea, aspartate aminotransferase (ASAT), and hemoglobin levels and the need for transfusion. The multivariate analysis showed that BMI (OR = 1.1, P = 0.004), preoperative creatinine level (OR = 11.1, P < 0.0001), use of vasopressor (OR = 3.31, P = 0.0002), maximal postoperative bilirubin level (OR = 1.44, P = 0.044) and minimal postoperative hemoglobin level (OR = 0.059, P = 0.0005) were independent predictors of early post-liver transplantation renal dysfunction. Neither donor status nor ASAT levels had significant impact on early postoperative renal dysfunction in multivariate analysis. Absence of renal dysfunction (group 1) was also predicted by the intraoperative hemostatic agent used, independently of the extent of bleeding and of the preoperative creatinine level.

CONCLUSION: More than half of receivers experienced some degree of early renal dysfunction after liver transplantation. Main predictors were preoperative renal dysfunction, postoperative anemia and vasopressor requirement.