Acute Kidney Injury After Liver Transplantation

Intraoperative Normal Saline Administration and Acute Kidney Injury in Patients Undergoing Liver Transplantation

BACKGROUND

Normal saline is still used in patients undergoing living donor liver transplantation (LDLT) with normonatremia. We investigated whether the normal saline administered during LDLT is associated with the increased risk of acute kidney injury (AKI) compared with the balanced crystalloids.

METHODS

We reviewed 1011 cases undergoing LDLT. The primary exposure variable was normal saline administered intraoperatively compared with the balanced crystalloid. To compare the risk of AKI after adjusting for potential confounders of baseline characteristics and surgical parameters, a propensity score matching analysis was performed. As a sensitivity analysis, ordinal logistic regression analysis was performed for AKI using inverse probability of treatment weighting (IPTW).

RESULTS

The incidence of AKI was significantly higher in the saline group (n = 88/174, 50.6%) than in the balanced group (n = 67/174, 38.5%) after matching (P = .010). The incidence of stage 2 or 3 AKI was also significantly higher in the saline group (n = 26/174, 14.9%) than in the balanced group (n = 43/174, 24.7%) after matching (P = .022). The length of hospital stay was significantly longer in the saline group than in the balanced group after matching. Ordinal logistic regression analysis using IPTW showed that the saline group showed a significant association of saline administration with the risk of AKI (odds ratio 1.23, 95% CI 1.05-1.28, P = .013).

CONCLUSION

Our propensity score analysis using propensity score matching and IPTW showed that normal saline administration during LDLT is associated with a high risk of postoperative AKI and longer hospital stays. However, our results should be interpreted carefully due to the relatively long period of data collection.

Post Liver Transplant Renal Dysfunction-Evaluation, Management and Immunosuppressive Practice

Liver transplantation (LT) is an effective and lifesaving treatment for patients with end-stage liver disease and hepatocellular carcinoma. Significant improvement in intermediate and long-term survival has been possible due to advancements in immunosuppressive therapy, perioperative care, and surgical techniques. Despite these advances, metabolic complications, including diabetes mellitus, cardiovascular diseases, malignancies, and renal dysfunction, are challenging issues after LT. Acute kidney injury (AKI) and chronic kidney disease (CKD) after LT are common and result in significant morbidity and mortality. Early diagnosis of kidney injury after LT is challenging, and no technique has yet proven effective in prediction of renal dysfunction. The methods for assessing renal function range from formulas that predict glomerular filtration rate to non-invasive biomarkers. The universal adoption of the model for end-stage liver disease has a direct impact on the incidence of peri-transplant AKI and development of CKD in the long-term. Post-LT renal dysfunction is multifactorial and is usually a result of pre-transplantation comorbidities, occurrence of renal dysfunction on the waiting list, perioperative events, and post-transplant nephrotoxic immunosuppressive medication use. Early identification of patients at risk for renal dysfunction and adoption of preventive measures are crucial in the pre-transplant period. No data are currently available to suggest a surgical technique that reliably demonstrates renal protection. Nephroprotective strategies during LT follow accepted surgical practice guidelines, such as maintenance of intravascular volume and mean arterial pressure. The management of kidney disease following LT is challenging, as by the time the serum creatinine is significantly elevated, few interventions impact the course of progression. Early nephroprotective measures are strongly advised and they mostly center on delaying the administration of calcineurin inhibitors (CNIs) during the initial postoperative period, lowering CNI dosage and combining CNI with mycophenolate mofetil and everolimus. The reasons for renal failure following LT, the techniques used to diagnose it, and the therapies designed to preserve renal function both immediately and late after LT are all critically evaluated in this review.

Securing the diagnosis of HRS-AKI: implications for current therapies

INTRODUCTION

Hepatorenal syndrome (HRS)-acute kidney injury (HRS-AKI) is a specific type of kidney injury seen in patients with cirrhosis and ascites and is associated with high mortality and morbidity. It is characterized by rapid deterioration of renal function due to reduced renal blood flow secondary to portal hypertensive splanchnic and systemic vasodilation. Early diagnosis and treatment of HRS-AKI are associated with greater likelihood of improvement in renal function, lower need for dialysis, and better post-transplant outcomes.

AREAS COVERED

This review discusses the diagnostic criteria for HRS-AKI, which has undergone several key changes over the last decade, with an aim to secure an early diagnosis and aid swift treatment initiation. Additionally, this review outlines the current treatment paradigms for HRS-AKI.

EXPERT OPINION

In the last 20 years, there have been several advances in understanding the pathophysiology and natural course of HRS-AKI. These have led to critical changes in its definition and diagnostic algorithm. However, prognosis of HRS-AKI remains dismal with no significant improvement in HRS-AKI reversal or HRS-related mortality over this time. We discuss several gaps in the current understanding and management of HRS-AKI that will benefit from further research.

Pulmonary artery catheter monitoring versus arterial waveform-based monitoring during liver transplantation: a retrospective cohort study

Although pulmonary artery catheter (PAC) has been used during liver transplantation surgery, the usefulness of PAC has rarely been investigated. We evaluated whether the use of PAC is associated with better clinical outcomes compared to arterial waveform-based monitoring after liver transplantation. A total of 1565 cases undergoing liver transplantation were reviewed. We determined whether patients received PAC or not and divided our cohort into the PAC with hemodynamic monitoring using PAC and the non-PAC with arterial waveform-based monitoring using FloTrac-Vigileo. Propensity score matching was performed. Acute kidney injury (AKI), early allograft dysfunction (EAD) and 1-year all-cause mortality or graft failure were compared in the matched cohorts. Logistic regression analysis was performed in the inverse probability of treatment-weighted (IPTW) cohort for postoperative EAD and AKI, respectively. Five-year overall survival was compared between the two groups. In the matched cohort, there was no significant difference in the incidence of AKI, EAD, length of hospital or ICU stay, and 1-year all-cause mortality between the groups. In the IPTW cohort, the use of PAC was not a significant predictor for AKI or EAD (AKI: odds ratio (95% confidence interval) of 1.20 (0.47-1.56), p = 0.229; EAD: 0.99 (0.38-1.14), p = 0.323). There was no significant difference in the survival between groups after propensity score matching (Log-rank test p = 0.578). In conclusion, posttransplant clinical outcomes were not significantly different between the groups with and without PAC. Anesthetic management without the use of PAC may be possible in low-risk patients during liver transplantation. The risk should be carefully assessed by considering MELD scores, ischemic time, surgical history, previous treatment of underlying liver disease, and degree of portal and pulmonary hypertension.Registration: https://clinicaltrials.gov/ct2/show/NCT05457114 (registration date: July 15, 2022).

Intraoperative hypotension and the risk of acute kidney injury following liver transplantation

BACKGROUND

Acute kidney injury (AKI) is a frequent adverse outcome following liver transplantation (LT) with a multifactorial etiology. It is critical to identify modifiable risk factors to mitigate the risk. One key area of interest is the role of intraoperative hypotension, which remains relatively unexplored in liver transplant cohorts.

METHODS

This was a retrospective observational cohort study of 1292 adult patients who underwent LT (between 2009 and 2019). Multivariable logistic regression analysis was used to explore the association between intraoperative hypotension, quantified by time duration (in min) under various mean arterial pressure (MAP) thresholds, and the primary outcome of early postoperative AKI according to the KDIGO criteria.

RESULTS

AKI occurred in 40% of patients and was independently associated with greater than 20 min spent below MAP thresholds of 55 mm Hg (adjusted OR = 1.866; 95% CI = 1.037-3.44; P = 0.041) and 50 mm Hg (adjusted OR = 1.801; 95% CI = 1.087-2.992; P = 0.023). Further sensitivity analyses demonstrated that the association between intraoperative hypotension and postoperative AKI was accentuated after restricting the analysis to patients with a normal preoperative renal function.

CONCLUSIONS

Prolonged (>20 min) intraoperative hypotension (below a MAP of 55 mm Hg) was independently associated with AKI following LT, after adjusting for several known confounders.

Anesthesia and Critical Care for the Prediction and Prevention for Small-for-size Syndrome: Guidelines from the ILTS-iLDLT-LTSI Consensus Conference

BACKGROUND

During the perioperative period of living donor liver transplantation, anesthesiologists and intensivists may encounter patients in receipt of small grafts that puts them at risk of developing small for size syndrome (SFSS).

METHODS

A scientific committee (106 members from 21 countries) performed an extensive literature review on aspects of SFSS with proposed recommendations. Recommendations underwent a blinded review by an independent expert panel and discussion/voting on the recommendations occurred at a consensus conference organized by the International Liver Transplantation Society, International Living Donor Liver Transplantation Group, and Liver Transplantation Society of India.

RESULTS

It was determined that centers with experience in living donor liver transplantation should utilize potential small for size grafts. Higher risk recipients with sarcopenia, cardiopulmonary, and renal dysfunction should receive small for size grafts with caution. In the intraoperative phase, a restrictive fluid strategy should be considered along with routine use of cardiac output monitoring, as well as use of pharmacologic portal flow modulation when appropriate. Postoperatively, these patients can be considered for enhanced recovery and should receive proactive monitoring for SFSS, nutrition optimization, infection prevention, and consideration for early renal replacement therapy for avoidance of graft congestion.

CONCLUSIONS

Our recommendations provide a framework for the optimal anesthetic and critical care management in the perioperative period for patients with grafts that put them at risk of developing SFSS. There is a significant limitation in the level of evidence for most recommendations. This statement aims to provide guidance for future research in the perioperative management of SFSS.

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.

Serum neutrophil gelatinase-associated lipocalin and lactate level during surgery predict acute kidney injury and early allograft dysfunction after liver transplantation

Early allograft dysfunction (EAD) and acute kidney injury (AKI) are common and clinically important complications after liver transplantation. Serum lactate level at the end of surgery could predict EAD and neutrophil gelatinase-associated lipocalin (NGAL) is known as a biomarker for AKI after liver transplantation. The authors investigated whether the combination of these two laboratory tests could be used as an early predictor of these two complications of EAD and AKI. We reviewed cases undergoing living donor liver transplantation (n = 353). Lactate-adjusted NGAL level, a combination of these two predictors, was calculated as the sum of each value multiplied by the odds ratio for EAD or AKI. We evaluated whether this combined predictor at the end of surgery is significantly associated with both postoperative AKI or EAD. We compared the area under the receiver operating characteristic curve (AUC) between our multivariable regression models with and without NGAL, lactate, or lactate-adjusted NGAL. NGAL, lactate and lactate-adjusted NGAL are significant predictors for EAD and AKI. The regression model for EAD or AKI including lactate-adjusted NGAL showed a greater AUC (for EAD: odds ratio [OR] 0.88, 95% confidence interval [CI] 0.84-0.91; for AKI: OR 0.89, 95% CI 0.85-0.92) compared to the AUC of the models including lactate (for EAD: OR 0.84, 95% CI 0.81-0.88; for AKI: OR 0.79, 95% CI 0.74-0.83) or NGAL alone (for EAD: OR 0.82, 95% CI 0.77-0.86; for AKI: OR 0.84, 95% CI 0.80-0.88) or the model without lactate or NGAL (for EAD: OR 0.64, 95% CI 0.58-0.69, for AKI: OR 0.75, 95% CI 0.70-0.79). In conclusion, lactate-adjusted NGAL level at the end of surgery could be a reliable combined laboratory predictor for postoperative EAD or AKI after liver transplantation with a greater discriminative ability than lactate or NGAL alone.

A Novel Online Calculator Predicting Acute Kidney Injury After Liver Transplantation: A Retrospective Study

Acute kidney injury (AKI) after liver transplantation (LT) is a common complication, and its development is thought to be multifactorial. We aimed to investigate potential risk factors and build a model to identify high-risk patients. A total of 199 LT patients were enrolled and each patient data was collected from the electronic medical records. Our primary outcome was postoperative AKI as diagnosed and classified by the KDIGO criteria. A least absolute shrinkage and selection operating algorithm and multivariate logistic regression were utilized to select factors and construct the model. Discrimination and calibration were used to estimate the model performance. Decision curve analysis (DCA) was applied to assess the clinical application value. Five variables were identified as independent predictors for post-LT AKI, including whole blood serum lymphocyte count, RBC count, serum sodium, insulin dosage and anhepatic phase urine volume. The nomogram model showed excellent discrimination with an AUC of 0.817 (95% CI: 0.758-0.876) in the training set. The DCA showed that at a threshold probability between 1% and 70%, using this model clinically may add more benefit. In conclusion, we developed an easy-to-use tool to calculate the risk of post-LT AKI. This model may help clinicians identify high-risk patients.

Diagnosis of Ischemic Renal Failure Using Surface-Enhanced Raman Spectroscopy and a Machine Learning Algorithm

To diagnose renal function using a biochip capable of detecting SERS and to assess Raman measurements taken from a bilateral renal ischemia model and the feasibility of early diagnosis was done. After generating a bilateral renal ischemia rat model, blood and urine were collected. After confirming the presence of renal injury and function, liquid drops were placed onto a Raman chip whose surface had been enhanced with Au-ZnO nanorods. SERS biomarkers that diffused into the nanogaps were selectively amplified. Raman signals varied based on the severity of the renal function, and these differences were confirmed statistically. These results confirm that renal ischemia leads to renal dysfunction and that surface-enhanced Raman spectroscopy and a machine learning algorithm can be used to track signals in the urine from the release of SERS biomarkers.

Effect of Propofol versus Sevoflurane Anesthesia on Acute Kidney Injury after Lung Transplantation Surgery: A Prospective Randomized Controlled Trial

This prospective randomized controlled trial aimed to compare the effects of sevoflurane and propofol anesthesia on the occurrence of acute kidney injury (AKI) following lung transplantation (LTx) surgery. Sixty adult patients undergoing bilateral LTx were randomized to receive either inhalation of sevoflurane or continuous infusion of propofol for general anesthesia. The primary outcomes were AKI incidence according to the Acute Kidney Injury Network (AKIN) criteria and blood biomarker of kidney injury, including neutrophil gelatinase-associated lipocalin (NGAL) and cystatin C levels within 48 h of surgery. Serum interleukin (IL)-1β, IL-6, tumor necrosis factor-α, and superoxide dismutase were measured before and after surgery. The post-operative 30-day morbidity and long-term mortality were also assessed. Significantly fewer patients in the propofol group developed AKI compared with the sevoflurane group (13% vs. 38%, p = 0.030). NGAL levels were significantly lower in the propofol group at immediately after, 24 h, and 48 h post-operation. IL-6 levels were significantly lower in the propofol group immediately after surgery. AKI occurrence was significantly associated with a lower 5-year survival rate. Total intravenous anesthesia with propofol reduced the AKI incidence in LTx compared with sevoflurane, which is understood to be mediated by the attenuation of inflammatory responses.

Novel Biomarkers of AKI in Cirrhosis

Acute kidney injury (AKI) is a frequent complication in patients with cirrhosis that is associated with poor outcomes and decreased survival. The definition of AKI in cirrhosis is currently based on changes of serum creatinine levels with respect to baseline values. Differential diagnosis of the causes of AKI is of major relevance, considering that some causes of AKI, such as hepatorenal syndrome, have specific treatment options and different prognosis. Prediction of kidney function recovery and patients' survival is also crucial in this patient population to guide clinical decisions. AKI biomarkers in cirrhosis have emerged as a promising tool for differential diagnosis and prognosis in this situation. There are consistent data showing that some urine biomarkers, particularly neutrophil gelatinase-associated lipocalin, may be useful in daily clinical practice for the differential diagnosis of the cause of AKI in cirrhosis. AKI biomarkers may constitute a useful tool for use in differential diagnosis, prognosis of renal function, and survival in patients with cirrhosis. This review focuses on the current state of knowledge and future perspective of novel biomarkers of AKI in cirrhosis.

Clinical Impact of Spontaneous Portosystemic Shunts in Liver Transplantation: A Comprehensive Assessment Through Total Shunt Area Measurement

BACKGROUND

The impact of spontaneous portosystemic shunts (SPSSs) on natural history of cirrhotic patients was recently evaluated through the measurement of total shunt area (TSA), a novel tool that allows a comprehensive assessment of SPSSs extension, identifying a direct correlation of higher TSA with lower patient survival. The role of SPSSs in liver transplant (LT) is still debated: we sought to investigate the clinical impact of TSA on the development of early allograft dysfunction (EAD), acute kidney injury (AKI), postoperative complications, and graft and patient survival following LT.

METHODS

Preoperative imaging of 346 cirrhotic patients undergoing primary LT between 2015 and 2020 were retrospectively revised, recording the size and anatomy of each SPSS to calculate TSA. The impact of TSA and selected patient and donor characteristics on the development of EAD, AKI, and clinically relevant complications was evaluated through univariate and multivariate logistic regression, whereas their effect on graft and patient survival was investigated through Cox regression analysis.

RESULTS

A TSA exceeding 78.54 mm 2 resulted as an independent risk factor for the development of EAD (odds ratio [OR]: 2.327; P = 0.003), grade 3 AKI (OR: 2.093; P = 0.041), and clinically relevant complications (OR: 1.962; P = 0.015). Moreover, higher TSA was significantly related to early graft and patient survivals, emerging as an independent risk factor for 12-mo graft loss (hazard ratio: 3.877; P = 0.007) and patient death (hazard ratio: 2.682; P = 0.018).

CONCLUSIONS

Higher TSA emerged as a significant risk factor for worse postoperative outcomes following LT, supporting the need for careful hemodynamic assessment and management of patients presenting multiple/larger shunts.

The Effects of sodium bicarbonate Ringer’s solution on acute kidney injury and the clinical outcomes after liver transplantation: A randomized controlled trial

Background: Acute kidney injury is the most common complication after liver transplantation. Sodium bicarbonate Ringer’s solution is a new type of crystalloid solution that has been recently used in the clinical setting. Whether sodium bicarbonate Ringer’s solution reduces the occurrence of postoperative AKI and improves the clinical outcomes of liver transplantation patients is not clear.

Objective: To compare the effects of sodium bicarbonate Ringer’s solution versus normal saline on acute kidney injury and clinical outcomes following classic orthotopic liver transplantation.

Methods: Sixty-four participants were randomly assigned to the sodium bicarbonate Ringers (BRS) group or the normal saline (NS) group. The primary outcomes were the incidence and severity of acute kidney injury after liver transplantation. The secondary outcomes included the rate of renal replacement therapy, length of mechanical ventilation, stay in the ICU, stay in the hospital after surgery and 30-day mortality. Other outcomes included the concentration of sodium, chloride, bicarbonate, anion gap, lactate concentration and changes in chloride preoperatively and postoperatively.

Result: Sixty-two patients completed the trial and were analyzed, with 31 patients in each group. There was a significantly lower rate of postoperative acute kidney injury in the BRS group (14/31, 45.2%) than in the NS group (24/31, 77.4%), with a relative risk of 0.58 (95% CI, 0.38–0.90; p = 0.009). The severity of AKI in the BRS group was lower than that in the NS group (Z = -2.932, p = 0.003). There was no significant difference observed in the secondary outcomes. For other outcomes, the concentration of preoperative sodium was lower than postoperative sodium in the NS group (137.2 vs. 140.4, p = 0.009). The concentration of preoperative chloride was lower than that of postoperative chloride in the NS group (102.9 vs. 106.2, p < 0.001). The change in the concentration of chloride in the BRS group was lower than that in the NS group (1.6 vs. 4.7, p = 0.006).

Conclusion: Sodium bicarbonate Ringer’s solution reduced the incidence and severity of acute kidney injury after classic orthotopic liver transplantation.

A retrospective observational study of the treatment with polymyxin B for liver transplantation recipients infected by multidrug-resistant gram-negative bacteria

WHAT IS KNOWN AND OBJECTIVE

Only a few studies about polymyxin B (PMB) against multidrug-resistant gram-negative bacteria (MDR GNB) infection were conducted in liver transplantation recipients (LTRs). The purpose of this study was to investigate the efficacy and safety of PMB in the treatment of MDR-GNB in liver transplant recipients and to determine the risk factors affecting clinical cure and 30-day all-cause mortality.

METHODS

Data of LTRs receiving PMB from January 2016 to February 2020 were collected. Clinical cure and 30-day all-cause mortality were the main efficacy outcomes, while the incidence of nephrotoxicity, neurotoxicity, and hyperpigmentation of PMB was the main safety outcome.

RESULTS AND DISCUSSION

Data of 42 LTRs were included. Clinical cure with PMB was observed in 27 recipients (64.3%), and the 30-day all-cause mortality rate was 31.0% (13/42). The incidence of acute kidney injury (AKI), neurotoxicity, and hyperpigmentation was 57.1% (16/28), 4.8% (2/42), and 16.7% (7/42), respectively. Logistic regression analysis showed that Acute Physiology and Chronic Health Evaluation (APACHE) II score (OR, 1.203; 95% CI, 1.016-1.423, p = 0.032) was an independent risk factor for 30-day all-cause mortality, whereas renal replacement therapy (OR, 0.128; 95% CI, 0.019-0.860, p = 0.034) was an independent risk factor for clinical cure with PMB.

WHAT IS NEW AND CONCLUSIONS

This is the first study to evaluate the application of PMB in LTRs. If there were no better therapeutic options left for LTRs other than PMB, it can be used against MDR GNB infection in LTRs. We should closely observe adverse events or reactions, and adjust the dose based on the balance of efficacy and safety.

Iohexol plasma and urinary concentrations in cirrhotic patients: A pilot study

BACKGROUND

Renal failure is an independent prognostic factor for survival in patients with cirrhosis. Equations to calculate serum creatinine significantly overestimate the glomerular filtration rate (GFR). Plasma clearance of direct biomarkers has been used to improve the accuracy of evaluations of GFR in this population, but no study has simultaneously measured plasma and urinary clearance, which is the gold standard.

AIM

To study calculated plasma and urinary concentrations of iohexol, based on the kinetics of samples collected over 24 h from cirrhotic patients with three different grades of ascites.

METHODS

One dose of iohexol (5 mL) was injected intravenously and plasma concentrations were measured 11 times over 24 h in nine cirrhotic patients. The urinary concentration of iohexol was also measured, in urine collected at 4, 8, 12 and 24 h.

RESULTS

The plasma and urinary curves of iohexol were similar; however, incomplete urinary excretion was detected at 24 h. Within the estimated GFR limits of our population (> 30 and < 120 mL/min/1.73 m²), the median measured GFR (mGFR) was 63.7 mL/min/1.73 m² (range: 41.3–111.3 mL/min/1.73 m²), which was an accurate reflection of the actual GFR. Creatinine-based formulas for estimating GFR showed significant bias and imprecision, while the Brochner–Mortensen (BM) equation accurately estimated the mGFR (r = 0.93).

CONCLUSION

Plasma clearance of iohexol seems useful for determining GFR regardless of the ascites grade. We will secondly devise a pharmacokinetics model requiring fewer samples andvalidate the BM equation.

Modelling kidney outcomes based on MELD eras - impact of MELD score in renal endpoints after liver transplantation

Background

Acute kidney injury is a common complication in solid organ transplants, notably liver transplantation. The MELD is a score validated to predict mortality of cirrhotic patients, which is also used for organ allocation, however the influence of this allocation criteria on AKI incidence and mortality after liver transplantation is still uncertain.

Methods

This is a retrospective single center study of a cohort of patients submitted to liver transplant in a tertiary Brazilian hospital: Jan/2002 to Dec/2013, divided in two groups, before and after MELD implementation (pre-MELD and post MELD). We evaluate the differences in AKI based on KDIGO stages and mortality rates between the two groups.

Results

Eight hundred seventy-four patients were included, 408 in pre-MELD and 466 in the post MELD era. The proportion of patients that developed AKI was lower in the post MELD era (p 0.04), although renal replacement therapy requirement was more frequent in this group (p < 0.01). Overall mortality rate at 28, 90 and 365 days was respectively 7%, 11% and 15%. The 1-year mortality rate was lower in the post MELD era (20% vs. 11%, p < 0.01). AKI incidence was 50% lower in the post MELD era even when adjusted for clinically relevant covariates (p < 0.01).

Conclusion

Liver transplants performed in the post MELD era had a lower incidence of AKI, although there were more cases requiring dialysis. 1-year mortality was lower in the post MELD era, suggesting that patient care was improved during this period.

Renal function after liver transplantation: Real-world experience with basiliximab induction and delayed reduced-dose tacrolimus

BACKGROUND

Routine use of delayed reduced-dose calcineurin-inhibitor treatment with induction immunosuppression in liver transplantation to minimize post-operative kidney injury is still scarce.

AIM

To evaluate real-world experience of basiliximab induction with delayed reduced-dose tacrolimus.

METHODS

In a retrospective cohort study, kidney function was evaluated pre- and postoperatively by measured glomerular filtration rate (mGFR). Adult patients undergoing liver transplantation between 2000 and 2017 were divided into a conventional treatment group (immediate-introduction of tacrolimus, target trough levels 10-15 ng/mL, and corticosteroids, n = 203) and a revised treatment group (basiliximab induction, reduced-dose tacrolimus, target through levels 5-8 ng/mL, delayed until day three, and mycophenolate mofetil 2000 mg/day, n = 343).

RESULTS

Mean mGFR was similar between groups at wait-listing (85.3 vs 84.1 ml/min/1.73m², p = 0.60), but higher in the revised treatment group at 3 (56.8 vs 63.4 ml/min/1.73m², p = 0.004) and 12 months post-transplant (60.9 vs 69.7 ml/min/1.73m², p<0.001); this difference remained after correcting for multiple confounders and was independent of pre-transplant mGFR. In the revised treatment group, biopsy proven acute rejection rate was lower (38% vs. 21%, p<0.001), and graft-survival better (p = 0.01).

CONCLUSION

Basiliximab induction with delayed reduced-dose tacrolimus is associated with less kidney injury when compared to standard-dose tacrolimus, without increased risk of rejection, graft loss or death.

Non-Renal Risk Factors for Chronic Kidney Disease in Liver Recipients with Functionally Intact Kidneys at 1 Month

Chronic kidney disease (CKD) is a critical complication of liver transplants, of which non-renal risk factors are not fully understood yet. This study aimed to reveal pre- and post-transplant risk factors for CKD (<60 mL/min/1.73 m2), examining liver recipients with functionally intact kidneys one month after grafting using nationwide cohort data. Baseline risk factors were analyzed with multivariable Cox regression analyses and post-transplant risk factors were investigated with the time-dependent Cox model and matched analyses of time-conditional propensity scores. Of the 2274 recipients with a one-month eGFR ≥ 60 mL/min/1.73 m2, 494 (22.3%) developed CKD during a mean follow-up of 36.6 ± 14.4 months. Age, female sex, lower body mass index, pre-transplant diabetes mellitus, and lower performance status emerged as baseline risk factors for CKD. Time-dependent Cox analyses revealed that recurrent hepatocellular carcinoma (HR = 1.93, 95% CI 1.06−3.53) and infection (HR = 1.44, 95% CI 1.12−1.60) were significant post-transplant risk factors for CKD. Patients who experienced one of those factors showed a significantly higher risk of subsequent CKD compared with the matched controls who lacked these features (p = 0.013 for recurrent hepatocellular carcinoma, and p = 0.003 for infection, respectively). This study clarifies pre- and post-transplant non-renal risk factors, which lead to renal impairment after LT independently from patients’ renal functional reserve.

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.

Risk factors for acute kidney injury after liver transplantation in intensive care unit: a retrospective cohort study

BACKGROUND

Acute kidney injury (AKI) is a frequent complication during the postoperative period following liver transplantation. Occurrence of AKI in intensive care unit (ICU) patients is associated with increased mortality and higher costs.

OBJECTIVE

To evaluate occurrences of moderate or severe AKI among patients admitted to the ICU after liver transplantation and investigate characteristics associated with this complication.

DESIGN AND SETTING

Single-center retrospective cohort study in a public hospital, Belo Horizonte, Brazil.

METHODS

Forty-nine patients admitted to the ICU between January 2015 and April 2017 were included. AKI was defined from a modified Kidney Disease Improving Global Outcomes (KDIGO) score (i.e. based exclusively on serum creatinine levels).

RESULTS

Eighteen patients (36.7%) developed AKI KDIGO 2 or 3; mostly KDIGO 3 (16 out of the 18 patients). Lactate level within the first six hours after ICU admission (odds ratio, OR: 1.3; 95% confidence interval, CI: 1.021-1.717; P = 0.034) and blood transfusion requirement within the first week following transplantation (OR: 8.4; 95% CI: 1.687-41.824; P = 0.009) were independently associated with development of AKI. Patients with AKI KDIGO 2 or 3 underwent more renal replacement therapy (72.2% versus 3.2%; P < 0.01), had longer hospital stay (20 days versus 15 days; P = 0.001), higher in-hospital mortality (44.4% versus 6.5%; P < 0.01) and higher mortality rate after one year (44.4% versus 9.7%; P = 0.01).

CONCLUSION

Need for blood transfusion during ICU stay and hyperlactatemia within the first six postoperative hours after liver transplantation are independently associated with moderate or severe AKI. Developing AKI is apparently associated with poor outcomes.

Prognostic Nomograms for Hospital Survival and Transplant-Free Survival of Patients with Hepatorenal Syndrome: A Retrospective Cohort Study

Hepatorenal syndrome (HRS) is a life-threatening complication of cirrhosis with a poor prognosis. To develop novel and effective nomograms which could numerically predict both the hospital survival and transplant-free survival of HRS, we retrospectively enrolled a cohort of 149 patients. A backward stepwise method based on the smallest Akaike information criterion value was applied to select the covariates to be included in the Cox proportional hazards models. The Harrell C-index, area under the receiver operating characteristic curve (AUC), Brier score, and Kaplan–Meier curves with the log-rank test were used to assess nomograms. The bootstrapping method with 1000 resamples was performed for internal validation. The nomogram predicting hospital survival included prothrombin activity, HRS clinical pattern, Child–Pugh class, and baseline serum creatinine. The C-index was 0.72 (95% confidence interval (CI), 0.65–0.78), and the adjusted C-index was 0.72 (95% CI, 0.66–0.79). The nomogram predicting transplant-free survival included sex, prothrombin activity, HRS clinical pattern, model for end-stage liver disease–Na score, and peak serum creatinine. The C-index of the nomogram was 0.74 (95% CI, 0.69–0.79), and the adjusted C-index was 0.74 (95% CI, 0.68–0.79). The AUC and Brier score at 15, 30, and 45 days calculated from the hospital survival nomogram and those at 6, 12, and 18 months calculated from the transplant-free survival nomogram revealed good predictive ability. The two models can be used to identify patients at high risk of HRS and promote early intervention treatment.

Practice guidance for the use of terlipressin for liver cirrhosis-related complications

BACKGROUND

Liver cirrhosis is a major global health burden worldwide due to its high risk of morbidity and mortality. Role of terlipressin for the management of liver cirrhosis-related complications has been recognized during recent years. This article aims to develop evidence-based clinical practice guidance on the use of terlipressin for liver cirrhosis-related complications.

METHODS

Hepatobiliary Study Group of the Chinese Society of Gastroenterology of the Chinese Medical Association and Hepatology Committee of the Chinese Research Hospital Association have invited gastroenterologists, hepatologists, infectious disease specialists, surgeons, and clinical pharmacists to formulate the clinical practice guidance based on comprehensive literature review and experts' clinical experiences.

RESULTS

Overall, 10 major guidance statements regarding efficacy and safety of terlipressin in liver cirrhosis were proposed. Terlipressin can be beneficial for the management of cirrhotic patients with acute variceal bleeding and hepatorenal syndrome (HRS). However, the evidence regarding the use of terlipressin in cirrhotic patients with ascites, post-paracentesis circulatory dysfunction, and bacterial infections and in those undergoing hepatic resection and liver transplantation remains insufficient. Terlipressin-related adverse events, mainly including gastrointestinal symptoms, electrolyte disturbance, and cardiovascular and respiratory adverse events, should be closely monitored.

CONCLUSION

The current clinical practice guidance supports the use of terlipressin for gastroesophageal variceal bleeding and HRS in liver cirrhosis. High-quality studies are needed to further clarify its potential effects in other liver cirrhosis-related complications.

Chronic Kidney Disease After Liver Transplantation

Improved survival after liver transplantation has led to an aging cohort of recipients at risk of renal dysfunction. The etiology of renal dysfunction is typically multifactorial; calcineurin inhibitors nephrotoxicity, pretransplant renal dysfunction, and perioperative acute kidney injury are important risk factors. Metabolic complications such as hypertension, diabetes mellitus, and metabolic-associated fatty liver disease also contribute to the development of renal disease. Most LT recipients will eventually develop some degree of renal dysfunction. Criteria to select candidates for simultaneous liver and kidney transplantation have been established. Both delayed introduction of CNIs and renal-sparing immunosuppressive regimens may reduce progression of renal dysfunction.

Perioperative management of adult living donor liver transplantation: Part 1 - recipients

Living donor liver transplantation was first developed to mitigate the limited access to deceased donor organs in Asia in the 1990s. This alternative liver transplantation option has become an established and widely practiced transplantation method for adult patients suffering from end-stage liver disease. It has successfully addressed the shortage of deceased donors. The Society for the Advancement of Transplant Anesthesia and the Korean Society of Transplant Anesthesia jointly reviewed published studies on the perioperative management of live donor liver transplant recipients. The review aims to offer transplant anesthesiologists and critical care physicians a comprehensive overview of the perioperative management of adult live liver transplantation recipients. We feature the status, outcomes, surgical procedure, portal venous decompression, anesthetic management, prevention of acute kidney injury, avoidance of blood transfusion, monitoring and therapeutic strategies of hemodynamic derangements, and Enhanced Recovery After Surgery protocols for liver transplant recipients. This article is protected by copyright. All rights reserved.

Use of an intraoperative veno-venous bypass during liver transplantation: an observational, single center, cohort study

BACKGROUND

As previous studies demonstrated conflicting results, we investigated the hemodynamic and renal outcomes of the intra-operative use of a veno-venous bypass during liver transplantation.

METHODS

The intraoperative levels of mean artery pressure, cardiac index, inferior vena cava and renal perfusion pressures were compared in liver transplant patients receiving or not the bypass.

RESULTS

We enrolled 38 patients: 20 with the bypass and 18 without. No differences characterized the two groups regarding gender (p=0.95), age (p=0.32), BMI (p=0.09), liver disease indicating LT and preoperative serum creatinine levels. Patients with the bypass received more intraoperative fluids (crystalloids and colloids) but with no difference in terms of intraoperative blood products and vasopressors requirements (p= 0.33). After clamping of the inferior vena cava, patients with the bypass showed higher mean artery pressure. Simultaneously, pressure in the inferior vena cava below the clamp level sharply increased Vs baseline (p<0.0001) independently of the use of the bypass and remained high until clamp release. Consequently, renal perfusion pressure dropped abruptly (p <0.0001) after vena cava clamping and returned to baseline only upon clamp removal. Overall, 18 subjects developed post-operative acute kidney injury which was equally distributed between patients with (n=9) or without (n =8) the bypass.

CONCLUSIONS

Our data suggest that the use of a veno-venous bypass fails to release the increased renal venous backflow from inferior vena cava clamping resulting in renal congestion with reduced renal perfusion pressure.

Race Adjustment in eGFR Equations Does Not Improve Estimation of Acute Kidney Injury Events in Patients with Cirrhosis

BACKGROUND

Accuracy of glomerular filtration rate estimating (eGFR) equations has significant implications in cirrhosis, potentially guiding simultaneous liver kidney allocation and drug dosing. Most equations adjust for Black race, partially accounted for by reported differences in muscle mass by race. Patients with cirrhosis, however, are prone to sarcopenia which may mitigate such differences. We evaluated the association between baseline eGFR and incident acute kidney injury (AKI) in patients with cirrhosis with and without race adjustment.

METHODS

We conducted a retrospective national cohort study of veterans with cirrhosis. Baseline eGFR was calculated using multiple eGFR equations including Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI), both with and without race adjustment. Poisson regression was used to investigate the association between baseline eGFR and incident AKI events per International Club of Ascites criteria.

RESULTS

We identified 72,267 patients with cirrhosis, who were 97.3% male, 57.8% white, and 19.7% Black. Over median follow-up 2.78 years (interquartile range 1.22-5.16), lower baseline eGFR by CKD-EPI was significantly associated with higher rates of AKI in adjusted models. For all equations this association was minimally impacted when race adjustment was removed. For example, removal of race adjustment from CKD-EPI resulted in a 0.1% increase in the association between lower eGFR and higher rate of AKI events per 15 mL/min/1.73 m² change (p < 0.001).

CONCLUSIONS

Race adjustment in eGFR equations did not enhance AKI risk estimation in patients with cirrhosis. Further study is warranted to assess the impacts of removing race from eGFR equations on clinical outcomes and policy.

Prognostic Impact of Early Recovering Acute Kidney Injury Following Liver Transplantation: A Multicenter Retrospective Study

BACKGROUND

Acute kidney injury (AKI) is a common complication after liver transplantation (LT), but the specific impact of rapidly resolving AKI is not elucidated. This study investigates the factors associated with early recovery from AKI and its association with post-LT outcomes.

METHODS

Retrospective analysis of 441 liver transplant recipients with end-stage liver disease without pretransplant renal impairment. AKI was defined according to Kidney Disease Improving Global Outcomes criteria and early renal recovery by its disappearance within 7 d post-LT.

RESULTS

One hundred forty-six patients (32%) developed a post-LT AKI, of whom 99 (69%) recovered early and 45 (31%) did not. Factors associated with early recovery were Kidney Disease Improving Global Outcomes stage 1 (odds ratio [OR],14.11; 95% confidence interval [CI], 5.59-40.22; P < 0.0001), minimum prothrombin time >50 % (OR, 4.50; 95% CI, 1.67-13.46; P = 0.003) and aspartate aminotransferase peak value <1000 U/L (OR, 4.07; 95% CI, 1.64-10.75; P = 0.002) within 48 h post-LT. Patients with early recovery had a renal prognosis similar to that of patients without AKI with no difference in estimated glomerular filtration rate between day 7 and 1 y. Their relative risk of developing chronic kidney disease was 0.88 (95% CI, 0.55-1.41; P = 0.6) with survival identical to patients without AKI and better than patients without early recovery (P < 0.0001).

CONCLUSIONS

Most patients with post-LT AKI recover early and have a similar renal prognosis and survival to those without post-LT AKI. Factors associated with early renal recovery are related to the stage of AKI, the extent of liver injury, and the early graft function. Patients at risk of not recovering may benefit the most from perioperative protective strategies, particularly those aimed at minimizing the adverse effects of calcineurin inhibitors.

[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.

Association between Gut Colonization of Vancomycin-resistant Enterococci and Liver Transplant Outcomes

BACKGROUND

Vancomycin-resistant enterococci (VRE) colonization is common in liver transplant recipients and has been associated with worse post-transplant outcomes.

METHODS

We conducted a retrospective cohort study at the University of Alberta Hospital including patients who underwent a liver transplant between September 2014 and December 2017.

RESULTS

Of 343 patients, 68 (19.8%) had pre-transplant VRE colonization and 27 (27/275, 9.8%) acquired VRE post-transplant, 67% were males and the median age was 56.5 years. VRE colonized patients at baseline had higher MELD scores and required longer post-transplant hospitalization. VRE colonization was associated with increased risk of early acute kidney injury (AKI) (64% vs 52%, p = 0. 044), clinically significant bacterial/fungal infection (29% vs 17%, p = 0. 012) and invasive VRE infection (5% vs 1%, p = 0. 017). Mortality at 2-years was 13% in VRE-colonized versus 7% in non-colonized (p = 0.085). On multivariate analysis, VRE colonization increased the risk of post-transplant AKI (HR 1.504, 95% CI: 1.077-2.100, p = 0.017) and clinically significant bacterial or fungal infection at 6 months (HR 2.038, 95%CI: 1.222-3.399, p = 0.006), and was associated with non-significant trend towards increased risk of mortality at 2-years post-transplant (HR 1.974 95% CI 0.890-4.378; p = 0.094).

CONCLUSIONS

VRE colonization in liver transplant patients is associated with increased risk of early AKI, clinically significant infections, and a trend towards increased mortality at 2-years. This article is protected by copyright. All rights reserved.

Literature review of the mechanisms of acute kidney injury secondary to acute liver injury

People exposed to liver ischaemia reperfusion (IR) injury often develop acute kidney injury and the combination is associated with significant morbidity and mortality. Molecular mediators released by the liver in response to IR injury are the likely cause of acute kidney injury (AKI) in this setting, but the mediators have not yet been identified. Identifying the mechanism of injury will allow the identification of therapeutic targets which may modulate both liver IR injury and AKI following liver IR injury.

Prophylactic Perioperative Terlipressin Therapy for Preventing Acute Kidney Injury in Living Donor Liver Transplant Recipients: A Systematic Review and Meta-Analysis

Background

Acute kidney injury (AKI) is common in the perioperative transplant period and is associated with poor outcomes. Few studies reported a reduction in AKI incidence with terlipressin therapy by counteracting the hemodynamic alterations occurring during liver transplantation. However, the effect of terlipressin on posttransplant outcomes has not been systematically reviewed.

Methods

A comprehensive search of electronic databases was performed. Studies reporting the use of terlipressin in the perioperative period of living donor liver transplantation were included. We expressed the dichotomous outcomes as risk ratio (RR, 95% confidence interval [CI]) using the random effects model. The primary aim was to assess the posttransplant risk of AKI. The secondary aims were to assess the need for renal replacement therapy (RRT), vasopressors, effect on hemodynamics, blood loss during surgery, hospital and intensive care unit (ICU) stay, and in-hospital mortality.

Results

A total of nine studies reporting 711 patients (309 patients in the terlipressin group and 402 in the control group) were included for analysis. Terlipressin was administered for a mean duration of 53.44 ± 28.61 h postsurgery. The risk of AKI was lower with terlipressin (0.6 [95% CI, 0.44-0.8]; P = 0.001). However, on sensitivity analysis including only four randomized controlled trials (I² = 0; P = 0.54), the risk of AKI was similar in both the groups (0.7 [0.43-1.09]; P = 0.11). The need for RRT was similar in both the groups (0.75 [0.35-1.56]; P = 0.44). Terlipressin therapy reduced the need for another vasopressor (0.34 [0.25-0.47]; P < 0.001) with a concomitant rise in mean arterial pressure and systemic vascular resistance by 3.2 mm Hg (1.64-4.7; P < 0.001) and 77.64 dyne cm^-1.sec^-5 (21.27-134; P = 0.007), respectively. Blood loss, duration of hospital/ICU stay, and mortality were similar in both groups.

Conclusions

Perioperative terlipressin therapy has no clinically relevant benefit.

Acute kidney injury and chronic kidney disease after liver transplant: A retrospective observational study

BACKGROUND AND RATIONALE

Chronic kidney disease remains an important risk factor for morbidity and mortality among LT recipients, but its exact incidence and risk factors are still unclear.

MATERIAL AND METHODS

We carried out a retrospective cohort study of consecutive adults who underwent liver transplant (January 2009-December 2018) and were followed (at least 6 months) at our institution. CKD was defined following the Kidney Disease: Improving Global Outcomes (KDIGO) 2012 Clinical Practice Guidelines. Long-term kidney function was classified into 4 groups: no CKD (eGFR, ≥60mL/min/1.73m²), mild CKD (eGFR, 30-59mL/min/1.73m²), severe CKD (eGFR, 15-29mL/min/1.73m²), and end-stage renal disease (ESRD).

RESULTS

We enrolled 410 patients followed for 53.2±32.6 months. 39 had CKD at baseline, and 95 developed de novo CKD over the observation period. There were 184 (44.9%) anti-HCV positive, 47 (11.5%) HBsAg positive, and 33 (8.1%) HBV/HDV positive recipients. Recipient risk factors for baseline CKD were advanced age (P=0.044), raised levels of serum uric acid (P<0.0001), and insulin dependent DM (P=0.0034). Early post-transplant AKI was common (n=95); logistic regression analysis found that baseline serum creatinine was an independent predictor of early post-LT AKI (P=0.0154). According to our Cox proportional hazards model, recipient risk factors for de novo CKD included aging (P<0.0001), early post-transplant AKI (P=0.007), and baseline serum creatinine (P=0.0002). At the end of follow-up, there were 116 LT recipients with CKD - 109 (93.9%) and 7 (6.1%) had stage 3 and advanced CKD, respectively. Only two of them are undergoing long-term dialysis.

CONCLUSION

The incidence of CKD was high in our cohort of LT recipients, but only a slight decline in kidney function over time was recorded. Prevention of post-transplant AKI will improve kidney function in the long run. We need more studies to analyze the function of kidneys among LT recipients over extended follow-ups and their impact on mortality.

Development and validation of a nomogram for predicting acute kidney injury after orthotopic liver transplantation

BACKGROUND

We aim to develop and validate a nomogram model for predicting severe acute kidney injury (AKI) after orthotopic liver transplantation (OLT).

METHODS

A total of 576 patients who received OLT in our center were enrolled. They were assigned to the development and validation cohort according to the time of inclusion. Univariable and multivariable logistic regression using the forward variable selection routine were applied to find risk factors for post-OLT severe AKI. Based on the results of multivariable analysis, a nomogram was developed and validated. Patients were followed up to assess the long-term mortality and development of chronic kidney disease (CKD).

RESULTS

Overall, 35.9% of patients were diagnosed with severe AKI. Multivariable logistic regression analysis revealed that recipients' BMI (OR 1.10, 95% CI 1.04-1.17, p = 0.012), hypertension (OR 2.32, 95% CI 1.22-4.45, p = 0.010), preoperative serum creatine (sCr) (OR 0.96, 95% CI 0.95-0.97, p < 0.001), and intraoperative fresh frozen plasm (FFP) transfusion (OR for each 1000 ml increase 1.34, 95% CI 1.03-1.75, p = 0.031) were independent risk factors for post-OLT severe AKI. They were all incorporated into the nomogram. The area under the ROC curve (AUC) was 0.73 (p < 0.05) and 0.81 (p < 0.05) in the development and validation cohort. The calibration curve demonstrated the predicted probabilities of severe AKI agreed with the observed probabilities (p > 0.05). Kaplan-Meier survival analysis showed that patients in the high-risk group stratified by the nomogram suffered significantly poorer long-term survival than the low-risk group (HR 1.92, p < 0.01). The cumulative risk of CKD was higher in the severe AKI group than no severe AKI group after competitive risk analysis (HR 1.48, p < 0.05).

CONCLUSIONS

With excellent predictive abilities, the nomogram may be a simple and reliable tool to identify patients at high risk for severe AKI and poor long-term prognosis after OLT.

Utilization and effectiveness of the organ procurement and transplantation network "safety-net" policy

BACKGROUND

Liver transplant recipients with persistent renal dysfunction may be prioritized on the kidney transplant waitlist based on the Organ Procurement and Transplantation Network "safety-net" policy implemented in 2017. The aim of this study was to evaluate the utilization of kidney transplant and posttransplant outcomes, of liver transplant recipients with persistent renal dysfunction before and after implementation of the Organ Procurement and Transplantation Network kidney safety-net policy and standardization of simultaneous liver-kidney requirements.

METHODS

Using the United Network for Organ Sharing database from January 2015 to March 2019, outcomes of liver transplant recipients listed for kidney transplant and the subset who received kidney after liver transplants were compared before and after policy implementation.

RESULTS

Liver transplant recipients listed for kidney transplant increased from 58 to 200, and kidney after liver transplants increased from 29.3% to 42.5% after safety-net policy implementation. Post-policy kidney after liver transplants received more local organs (91.8% vs 70.6%, P = .03) and trended toward shorter waitlist time (47 [17-123] vs 84 [37-226] days, P = .051). The pre- and post-policy cohorts had similar (P > .05) kidney donor profile index (0.43 [0.27-0.69] vs 0.42 [0.28-0.58]) and delayed graft function (11.8% vs 14.1%). Patient, kidney graft, and liver graft survival were similar (P > .05) between pre and post-policy cohorts. Patient and kidney graft survival were similar between kidney after liver transplants and propensity score-matched kidney transplant alone recipients. Patient, kidney, and liver graft survival were similar between kidney after liver transplants and propensity score-matched simultaneous liver-kidney transplant recipients.

CONCLUSION

This study demonstrates that after Organ Procurement and Transplantation Network "safety-net" policy implementation, there has been an increase in liver transplant recipients with renal dysfunction who are listed for and undergo kidney transplant with excellent short-term results.

Intraoperative systemic biomarkers predict post-liver transplantation acute kidney injury

OBJECTIVE

Liver transplant (LT) is a definitive therapeutic option for patients with chronic liver disease. However, acute kidney injury after LT (post-LT AKI) is a frequent complication that may lead to graft dysfunction and decrease life expectancy. Delay in AKI detection by traditional biomarkers boosted research with new biomarkers for post-LT AKI as neutrophil gelatinase-associated lipocalin (NGAL) and syndecan-1. We aim to evaluate associations of intraoperative systemic NGAL and syndecan-1 levels with post-LT AKI.

METHODS

This is a prospective study conducted in 46 patients selected for LT. Patients were evaluated preoperatively and blood samples were collected intraoperatively: T1 (after induction of anesthesia), T2 (anhepatic phase) and T3 (2 h after reperfusion of the graft).

RESULTS

The mean age was 54 ± 12 years and 60% were male. Post-LT AKI was observed in 24 (52%) patients of which 12% needed dialysis. Serum NGAL and syndecan-1 increased along surgical phases. Mostly, increment values of serum NGAL of T2 to T3 and syndecan-1 at T3 were importantly associated with post-LT AKI. Into a multivariate model with model for end-stage liver disease score, age, gender, warm ischemia, cold ischemia and surgery time, syndecan-1 levels at T3 remains capable to predict post-LT AKI. Serum NGAL had significance only with increment values calculated by the ratio of 'T3/T2'. Finally, serum syndecan-1 at T3 had a better diagnostic performance in receiver operating characteristic curve analysis.

CONCLUSION

Serum syndecan-1 levels in 2 h after reperfusion were most useful in early post-LT AKI diagnosis and may be used to construct new risk groups in this context.

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.

Estimating Glomerular Filtration Rate in Cirrhosis Using Creatinine-Based and Cystatin C-Based Equations: Systematic Review and Meta-Analysis

Accurate estimation of kidney function in cirrhosis is crucial for prognosis and decisions regarding dual-organ transplantation. We performed a systematic review/meta-analysis to assess the performance of creatinine-based and cystatin C (CysC)-based eGFR equations compared with measured GFR (mGFR) in patients with cirrhosis. A total of 25 studies (n = 4565, 52.0 years, 37.0% women) comprising 18 equations met the inclusion criteria. In all GFR equations, the creatinine-based equations overestimated GFR (standardized mean difference, SMD, 0.51; 95% confidence interval [CI], 0.31-0.71) and CysC-based equations underestimated GFR (SMD, -0.3; 95% CI, -0.60 to -0.02). Equations based on both creatinine and CysC were the least biased (SMD, -0.14; 95% CI, -0.46 to 0.18). Chronic kidney disease-Epi-serum creatinine-CysC (CESC) was the least biased but had low precision and underestimated GFR by -3.6 mL/minute/1.73 m² (95% CI, -17.4 to 10.3). All equations significantly overestimated GFR (+21.7 mL/minute/1.73 m² ; 95% CI, 17.7-25.7) at GFR <60 mL/minute/1.73 m² ; of these, chronic kidney disease-Epi-CysC (10.3 mL/minute/1.73 m² ; 95% CI, 2.1-18.4) and GFR Assessment in Liver Disease (12.6 mL/minute/1.73 m² ; 95% CI, 7.2-18.0) were the least biased followed by Royal Free Hospital (15 mL/minute/1.73 m² ; 95% CI, 5.5-24.6) and Modification of Diet in Renal Disease 6 (15.7 mL/minute/1.73 m² ; 95% CI, 10.6-20.8); however, there was an overlap in the precision of estimates, and the studies were limited. In ascites, overestimation of GFR was common (+8.3 mL/minute/1.73 m² ; 95% CI, -3.1 to 19.7). However, overestimation of GFR by 10 to 20 mL/minute/1.73m² is common in patients with cirrhosis with most equations in ascites and/or kidney dysfunction. A tailored approach is required especially for decisions regarding dual-organ transplantation.

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.

New Indications for Liver Transplantation

Liver transplantation (LT) is an important therapeutic option for the treatment of several liver diseases. Modern LT is characterized by remarkable improvements in post-transplant patient survival, graft survival, and quality of life. Thanks to these great improvements, indications for LT are expanding. Nowadays, clinical conditions historically considered exclusion criteria for LT, have been considered new indications for LT, showing survival advantages for patients. In this review, we provide an updated overview of the principal newer indications for LT, with particular attention to alcoholic hepatitis, acute-on-chronic liver failure (ACLF), cholangiocarcinoma and colorectal cancer metastases.

Liver Transplantation in Acute-on-chronic Liver Failure

Liver transplantation (LT) has revolutionized outcomes for cirrhotic patients. Current liver allocation policies dictate patients with highest short-term mortality receive the highest priority, thus, several patients become increasingly ill on the waitlist. Given cirrhosis is a progressive disease, it can be complicated by the occurrence of acute-on-chronic liver failure (ACLF), a syndrome defined by an acute deterioration of liver function associated with extrahepatic organ failures requiring intensive care support and a high short-term mortality. Successfully bridging to transplant includes accurate prognostication and prioritization of ACLF patients awaiting LT, optimizing intensive care support pre-LT, and tailoring immunosuppressive and anti-infective therapies post-LT. Furthermore, predicting futility (too sick to undergo LT) in ACLF is challenging. In this review, we summarize the role of LT in ACLF specifically highlighting (a) current prognostic scores in ACLF, (b) critical care management of the ACLF patient awaiting LT, (c) donor issues to consider in transplant in ACLF, and (d) exploring of recent post-LT outcomes in ACLF and potential opportunities to improve outcomes including current care gaps and unmet research needs.

Early prediction of acute kidney injury after liver transplantation by scoring system and decision tree

BACKGROUND AND AIMS

Early detection of acute kidney injury (AKI) is crucial for the prognosis of patients after liver transplantation (LT). This passage aims to analyze the perioperative clinical markers of AKI after LT and establish predictive models based on clinical variables for early detection of AKI after LT.

METHODS

We prospectively collected 109 patients with LT, and compared the differences of perioperative clinical markers between the AKI group and non-AKI group. The scoring system and decision tree model were established through the risk factors. Another 163 patients who underwent LT in the same center from 2017 to 2018 were retrospectively collected to verify the models.

RESULTS

In multiple comparisons of risk factors of post-LT AKI, pre-operative factors were excluded automatically, intraoperative and post-operative factors including operating time, intraoperative hypotension time, post-operative infection, the peak of post-operative AST, and post-operative shock were the independent risk factors for post-LT AKI. The scoring system established with the risk factors has good predictive power (AUC = 0.755) in the validation cohort. The decision tree also shows that post-operative shock was the most important marker, followed by post-operative infection.

CONCLUSION

Five intraoperative and post-operative factors are independently associated with post-LT AKI rather than pre-operative factors, which indicates that operation technique and post-operative management may more important for the prevention of post-LT AKI. The scoring system and decision tree model could complement each other, and provide quantitative and intuitive prediction tools for clinical practice of early detection of post-LT AKI.

Evaluation of Longitudinal Exposure to Tacrolimus as a Risk Factor of Chronic Kidney Disease Occurrence Within the First-year Post-Liver Transplantation

BACKGROUND

Renal failure is predictive of mortality in the early postliver-transplantation period and calcineurin inhibitors toxicity is a main challenge. Our aim is to assess the impact of longitudinal tacrolimus exposure (TLE) and other variables on chronic kidney disease (CKD)-free 1-year-survival.

METHODS

Retrospective data of consecutive patients transplanted between 2011 and 2016 and treated with tacrolimus were collected. TLE and all relevant pre- and post-liver transplantation (LT) predictive factors of CKD were tested and included in a time-to-event model. CKD was defined by repeated estimated glomerular filtration rate (eGFR) values below 60 mL/min/1.73m2 at least for the last 3 months before M12 post-LT.

RESULTS

Data from 180 patients were analyzed. CKD-free survival was 74.5% and was not associated with TLE. Pre-LT acute kidney injury (AKI) and eGFR at 1-month post-LT (eGFRM1) <60 mL/min/1.73m2 were significant predictors of CKD. By distinguishing 2 situations within AKI (ie, with or without hepatorenal syndrome [HRS]), only HRS-AKI remained associated to CKD. HRS-AKI and eGFRM1 <60 mL/min/1.73m2 increased the risk of CKD (hazard ratio, 2.5; 95% confidence interval, 1.2-4.9; hazard ratio, 4.8; 95% confidence interval, 2.6-8.8, respectively).

CONCLUSIONS

In our study, TLE, unlike HRS-AKI and eGFRM1, was not predictive of CKD-free survival at 1-year post-LT. Our results once again question the reversibility of HRS-AKI.