Risk factors for acute renal injury in living donor liver transplantation: evaluation of the RIFLE criteria

Urinary dickkopf-3 as a predictor for postoperative acute kidney injury in the intensive care unit

BACKGROUND

As a life-threatening complication in patients undergoing surgery, acute kidney injury (AKI) is strongly associated with a worse prognosis. Urinary dickkopf-related protein 3 (DKK3) has been identified as a biomarker for predicting postoperative AKI in patients undergoing cardiac surgery.

OBJECTIVE

To investigate the predictive value of urinary DKK3 on postoperative AKI and develop a clinical model based on the predictor for predicting the development of AKI within seven days for patients undergoing noncardiac surgery.

METHODS

All patients who were admitted to the Intensive Care Unit (ICU) after noncardiac surgery from March 2023 to June 2023 were included in this study. The patients' baseline data on demographic characteristics, lifestyle risk factors, medical history, clinical features, and laboratory tests before surgery were collected at the time of admission. Besides, the blood samples for cystatin C and routine laboratory tests and the urine samples for DKK3 tests were simultaneously collected at the time of admission to the ICU. In addition, the independent predictors of postoperative AKI were identified by univariate, multivariate, and LASSO analyses. Moreover, a nomogram for predicting postoperative AKI was developed based on these independent predictors. Finally, the nomogram was evaluated through calibration and decision curve analyses.

RESULTS

A total of 166 patients with a median age of 67 years old were included in this study, including 94 (56.63 %) males. Among these patients, 47 patients (28.3 %) developed postoperative AKI. Additionally, 7 independent risk factors, including preoperative serum creatinine, preoperative eGFR, preoperative serum albumin, preoperative serum potassium ion, cystatin C, uDKK3/uCr, and SOFA score, were selected by univariate and multivariate regression analyses. Eventually, 4 independent risk factors (including preoperative eGFR, cystatin C, uDKK3/uCr, and SOFA score) identified in this study by LASSO analyses were used to establish the nomogram. The area under the receiver operating characteristic (ROC) curve (AUC) for the prediction model was 0.868. The calibration curve and decision curve analysis results demonstrated that the nomogram had good prediction performance.

CONCLUSIONS

Urinary DKK3/creatinine was independently associated with postoperative AKI for patients in the ICU after noncardiac surgery. The nomogram constructed based on uDKK3/uCr, preoperative eGFR, cystatin C, and SOFA score showed a higher accuracy in predicting postoperative AKI.

Impact of preoperative nonselective beta-blocker use on acute kidney injury after living donor liver transplantation: Propensity score analysis

INTRODUCTION AND OBJECTIVES

Acute kidney injury (AKI) is prevalent and has deleterious effects on postoperative outcomes following liver transplantation (LT). The impact of nonselective beta-blockers (NSBBs) in patients with liver cirrhosis remains controversial. This study investigated the association between preoperative NSBB use and AKI after living donor LT (LDLT).

PATIENTS AND METHODS

We evaluated 2,972 adult LDLT recipients between January 2012 and July 2022. The patients were divided into two groups based on the preoperative NSBB use. Propensity score matched (PSM) and inverse probability of treatment weighting (IPTW) analyses were performed to evaluate the association between preoperative NSBB use and postoperative AKI. Multiple logistic regression analyses were also used to identify the risk factors for AKI.

RESULTS

The overall incidence of AKI was 1,721 (57.9%) cases. The NSBB group showed a higher incidence of AKI than the non-NSBB group (62.4% vs. 56.7%; P = 0.011). After PSM and IPTW analyses, no significant difference in the incidence of AKI was found between the two groups (Odds ratio, OR 1.13, 95% confidence interval, CI 0.93-1.37, P = 0.230, PSM analysis; OR 1.20, 95% CI 0.99-1.44, P = 0.059, IPTW analysis). In addition, preoperative NSBB use was not associated with AKI after multivariate logistic regression analysis (OR 1.16, 95% CI 0.96-1.40, P = 0.118).

CONCLUSIONS

Preoperative NSBB use was not associated with AKI after LDLT. Further studies are needed to validate our results.

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.

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).

Long Term Complications of Immunosuppression Post Liver Transplant

Improvement in immunosuppression has led to a remarkable improvement in short-term and long-term outcomes post-liver transplant (LT). However, with improvements in long-term survival, complications related to immunosuppressive drugs, either directly or indirectly, have also increased. The adverse events could be drug-specific, class-specific, or generic. Calcineurin inhibitors (cyclosporine and tacrolimus) are the backbone of the immunosuppression after LT and the main culprit associated with most of the complications, including renal failure, post-transplant diabetes mellitus (PTDM), and metabolic syndrome. Steroids are also implicated in the development of diabetes, osteoporosis, and metabolic syndrome post-LT. The development of infections and de novo malignancies (DNMs) is a generic effect linked to the overall cumulative immunosuppression. The development of these complications significantly hampers the quality of life and leads to increased morbidity and mortality post-LT. Thus, it is important to minimize the cumulative immunosuppression dose while simultaneously preventing allograft rejection. This review provides up-to-date, comprehensive knowledge of the complications of long-term immunosuppression post-LT along with associated risk factors and strategies to minimize the risk of complications.

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.

Lack of furosemide responsiveness predict severe acute kidney injury after liver transplantation

Acute kidney injury (AKI) remains to be a common but severe complication after liver transplantation (LT). However, there are still few clinically validated biomarkers. A total of 214 patients who underwent routine furosemide (1-2 mg/kg) after LT were retrospectively included. The urine output during the first 6 h was recorded to evaluate the predictive value of AKI stage 3 and renal replacement therapy (RRT). 105 (49.07%) patients developed AKI, including 21 (9.81%) progression to AKI stage 3 and 10 (4.67%) requiring RRT. The urine output decreased with the increasing severity of AKI. The urine output of AKI stage 3 did not significantly increase after the use of furosemide. The area under the receiver operator characteristic (ROC) curves for the total urine output in the first hour to predict progression to AKI stage 3 was 0.94 (p < 0.001). The ideal cutoff for predicting AKI progression during the first hour was a urine volume of less than 200 ml with a sensitivity of 90.48% and specificity of 86.53%. The area under the ROC curves for the total urine output in the six hours to predict progression to RRT was 0.944 (p < 0.001). The ideal cutoff was a urine volume of less than 500 ml with a sensitivity of 90% and specificity of 90.91%. Severe AKI after liver transplantation seriously affects the outcome of patients. Lack of furosemide responsiveness quickly and accurately predict AKI stage 3, and patients requiring RRT after the operation.

Comparing the effect of administering gelatin-low dose albumin versus albumin on renal function in liver transplantation: A randomized clinical trial

BACKGROUND

Acute kidney injury (AKI) is a common complication after liver transplantation (LT) that is independently associated with an increased risk of morbidity and mortality. This study aimed to evaluate the effects of administering gelatin-low dose albumin versus albumin on renal function and other early outcomes in LT.

METHODS

This randomized controlled clinical trial was conducted on 140 patients undergoing LT from brain death donors. Patients were randomly assigned to two groups: albumin or modified gelatin with albumin. Blood samples were collected before (T0) and on the first (T1), second (T2), third (T3), fifth (T4), and last day of hospitalization (T5) after LT for the detection of laboratory parameters, including renal and liver function tests.

RESULTS

The incidence of AKT on the basis of RIFLE criteria was 31.42% in the gelatin group (R: 59.10%, I: 36.40%, and F: 4.50%) and 25.71% in the albumin group (R: 66.70%, I: 27.80%, and F: 5.50%) (p = .845). Two patients in the gelatin and one in the albumin groups required renal replacement therapy (RRT). There was no significant difference between groups when the trends of changes in renal and liver function parameters were assessed during the study period (T0-T5). Furthermore, the incidence of complications was similar across groups.

CONCLUSION

This study showed that modified gelatin could be used without inappropriate outcomes on renal function in patients with normal preoperative kidney function tests undergoing LT.

Postreperfusion Syndrome in Liver Transplant: A Risk Factor for Acute Kidney Failure: A Retrospective Analysis

The maximum expression of hemodynamic instability during liver transplant is the so-called postreperfusion syndrome (PRS) that increases both overall mortality and postoperative complications. It was first defined by Aggarwal et al in 1987, but the results are still conflicting when establishing the relationship between PRS and acute kidney failure (AKF). We conducted a retrospective observational study of transplant recipients with deceased-donor liver grafts between January 2002 and December 2018. We analyzed the incidence of PRS and its potential negative impact over kidney function. A total of 551 transplants were analyzed. PRS was recorded in 130 patients (23.6%). The incidence of AKF was 61.5%. A total of 111 patients required kidney replacement therapy (32.7%). Regarding the severity of AKF, 128 patients were classified as acute kidney injury (AKI) 1 (23.2%), 76 as AKI 2 (13.8%), and 135 as AKI 3 (24.5%). In the group with PRS, 75.4% (n = 98) developed AKF vs 57.2% (n = 241) in the group without PRS. In the multivariate analysis we found a relationship between PRS and AKF with an odds ratio of 2.18 (95% CI, 1.30-3.64; P = .003), once adjusted by the length of the anhepatic phase, donor age, Model for End-Stage Liver Disease score, history of ascites, and need for early surgical reintervention. The incidence of AKF decreased (44.5%) ever since the implementation of delayed calcineurin inhibitors therapy and piggyback surgical technique, but a clear influence of the occurrence of PRS on the development of AKF is still observed, with an OR of 3.78 (95% CI, 1.92-7.43; P < .001), once adjusted by albumin and hemoglobin levels, Model for End-Stage Liver Disease score, and Child classification.

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.

[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.

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

BACKGROUND

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSION

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

Current aspects of renal dysfunction after liver transplantation

The development of chronic kidney disease (CKD) after liver transplantation (LT) exerts a severe effect on the survival of patients. The widespread adoption of the model for end-stage liver disease score strongly impacted CKD incidence after the procedure, as several patients are transplanted with previously deteriorated renal function. Due to its multifactorial nature, encompassing pre-transplantation conditions, perioperative events, and nephrotoxic immunosuppressor therapies, the accurate identification of patients under risk of renal disease, and the implementation of preventive approaches, are extremely important. Methods for the evaluation of renal function in this setting range from formulas that estimate the glomerular filtration rate, to non-invasive markers, although no option has yet proved efficient in early detection of kidney injury. Considering the nephrotoxicity of calcineurin inhibitors (CNI) as a factor of utmost importance after LT, early nephroprotective strategies are highly recommended. They are based mainly on delaying the application of CNI during the immediate postoperative-period, reducing their dosage, and associating them with other less nephrotoxic drugs, such as mycophenolate mofetil and everolimus. This review provides a critical assessment of the causes of renal dysfunction after LT, the methods of its evaluation, and the interventions aimed at preserving renal function early and belatedly after LT.

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.

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.

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

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

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.

Position paper on liver and kidney diseases from the Italian Association for the Study of Liver (AISF), in collaboration with the Italian Society of Nephrology (SIN)

Liver and kidney are strictly connected in a reciprocal manner, in both the physiological and pathological condition. The Italian Association for the Study of Liver, in collaboration with the Italian Society of Nephrology, with this position paper aims to provide an up-to-date overview on the principal relationships between these two important organs. A panel of well-recognized international expert hepatologists and nephrologists identified five relevant topics: 1) The diagnosis of kidney damage in patients with chronic liver disease; 2) Acute kidney injury in liver cirrhosis; 3) Association between chronic liver disease and chronic kidney disease; 4) Kidney damage according to different etiology of liver disease; 5) Polycystic kidney and liver disease. The discussion process started with a review of the literature relating to each of the five major topics and clinical questions and related statements were subsequently formulated. The quality of evidence and strength of recommendations were graded according to the GRADE system. The statements presented here highlight the importance of strong collaboration between hepatologists and nephrologists for the management of critically ill patients, such as those with combined liver and kidney impairment.

Diabetes mellitus is a risk factor of acute kidney injury in liver transplantation patients

BACKGROUND

Diabetes mellitus has become an increasing global health burden with rapid growing prevalence. Patients with diabetes have higher susceptibility to acute kidney injury (AKI). Liver transplantation (LT) predisposes the kidney to injury. However, the association between diabetes and AKI in LT patients remains unclear.

METHODS

We conducted a retrospective cohort study examining risk factors for AKI in patients undergone orthotopic LT. Potential risk factors including baseline estimated glomerular filtration rate (eGFR), the model for end-stage liver disease (MELD) score, diabetes, hypertension and intraoperative blood loss were screened. The primary endpoint was AKI occurrence. Multivariate logistic regression was used to analyze the association between potential risk factors and AKI.

RESULTS

A total of 291 patients undergone orthotopic LT were included in the present study. Among them, 102 patients (35.05%) developed AKI within 5 days after LT. Diabetes was identified as an independent risk factor for AKI. Patients who developed AKI had worse graft function recovery and higher mortality within 14 days after LT compared to those who did not develop AKI. AKI patients with diabetes had a significant decline of eGFR within the first postoperative year, compared with patients who did not develop AKI and who developed AKI but without diabetes.

CONCLUSIONS

Diabetes is an independent risk factor for AKI after orthotopic LT. AKI is associated with delayed graft function recovery and higher mortality in short-term postoperative period. Diabetic patients who developed AKI after LT experience a faster decline of eGFR within the first year after surgery.

Modifiable risk factors of acute kidney injury after liver transplantation: a systematic review and meta-analysis

BACKGROUND

Acute kidney injury (AKI) is a common and critical complication of liver transplantation (LT), which is associated with increased morbidity, mortality and health care cost. We aimed to identify modifiable risk factors of AKI after LT.

METHODS

A literature search of Pubmed, EMBASE and Cochrane Databases was performed to identify studies investigating risk factors of AKI after LT. The Newcastle-Ottawa Scale was used to rate study quality. Effect size and 95% confidence interval were pooled using a random-effect model with inverse-variance method.

RESULTS

Sixty-seven articles with 28,844 patients were included in the meta-analysis. Seventeen modifiable risk factors were found, including overweight, preoperative use of diuretic, preoperative anemia, donation after cardiac death organ, donor BMI ≥ 30 kg/m2, ABO-incompatible LT, low graft to recipient body weight ratio, intraoperative hypotension, major bleeding, intraoperative use of vasopressor, large RBC transfusion, postreperfusion syndrome, postoperative use of vasopressors, overexposure to calcineurin inhibitor, calcineurin inhibitor without mycophenolate mofetil, graft dysfunction and infection. A total of 38 articles were included in the systematic review, in which 8 modifiable risk factors and 1 protective factor were additionally associated in single studies with the incidence of AKI after LT.

CONCLUSIONS

Effective interventions based on identified modifiable risk factors in the perioperative management and graft allocation and preservation may be promising to reduce the incidence of AKI after LT.

TRIAL REGISTRATION

The protocol for this systematic review is registered with PROSPERO (No. CRD42020166918 ).

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.

Biomarkers for detecting and improving AKI after liver transplantation: From diagnosis to treatment

Orthotopic liver transplantation (OLT) is a well-established treatment for patients with liver failure. The shortage of donor organs and postoperative complications remain major obstacles for improving patient survival. Among these complications, acute kidney injury (AKI) is one of the most frequent types, contributing to graft loss. The timely detection and reversal of AKI can reduce its adverse influences on graft and patient outcomes. Traditional markers for detecting AKI are often limited with regard to their accuracy and specificity, and the discovery of better AKI markers and therapeutic targets assumes great importance. During past decades, studies directed toward early detection and treatment of AKI in OLT have been available. This review summarizes the evidence of these biomarkers for the prediction, diagnosis, treatment and prognosis stratification of AKI associated with OLT.

Different Severity of Clinical Outcomes Between the 2 Subgroups of Stage 1 Acute Kidney Injury After Liver Transplantation

BACKGROUND

Although the Kidney Disease: Improving Global Outcomes (KDIGO) criteria is used to define acute kidney injury (AKI) after liver transplantation, the criteria was criticized for including 2 heterogeneous groups of different serum creatinine (sCr) criteria together in AKI stage 1. We investigated whether there are significant differences in clinical outcomes between 2 subgroups of patients within AKI stage 1.

METHODS

A total of 1440 cases were reviewed. The AKI stage 1 (n = 443) were divided into 2 subgroups based on changes in sCr level (stage 1a: ≥0.3 mg/dL of absolute sCr increase, n = 251; stage 1b: ≥50% relative sCr increase, n = 192). Propensity score analysis was performed between stage 1a and 1b groups, yielding 157 matched pairs. We compared the length of hospital stay, early allograft dysfunction, and 5-year all-cause mortality between these subgroups after matching. Kaplan-Meier analyses were performed to compare the graft or overall survival between the subgroups after matching. Sensitivity analysis for Acute Kidney Injury Network (AKIN) criteria was performed.

RESULTS

Length of hospital stay and 5-year all-cause mortality was significantly worse in patients with stage 1b compared to stage 1a after matching. Five-year graft or patient survival was significantly worse in patients with stage 1b compared to stage 1a after matching (Log-rank test P = 0.022 and P = 0.027, respectively). These results were the same regarding AKIN criteria.

CONCLUSIONS

The KDIGO criteria for AKI stage 1 could be further divided into 2 substages with different severity of clinical outcomes. This modified criteria could give additional prognostic information in patients undergoing liver transplantation.

Chronic severe hepatitis and preoperative creatinine are independent risk factors for acute kidney injury after liver transplantation

Background

Orthotopic liver transplantation (OLT) offers the highest chance of cure in comparison with all other treatment for liver tumors and other end stage liver disease. However, the complications caused by liver transplantation significantly affect its therapeutic effect, and acute kidney injury (AKI) is one of the most common of these. It is, therefore, necessary to identify the risk factors of AKI after liver transplantation.

Methods

A single-center, retrospective study of patients receiving liver transplantation at the Beijing Chao-Yang Hospital between January 2015 to January 2019 was conducted.

Patients were divided into a normal control group and AKI group based on their previous medical history. Preoperative and intraoperative indicators including preoperative creatinine, uric acid, and the intraoperative input of protein were then recorded.

Results

A total of 419 patients were enrolled into the study. The control group consisted of 336 patients while 83 patients formed an AKI group based on the grading criteria of AKI. There were significant differences in chronic severe hepatitis (P=0.001), liver cancer (P=0.044), intraoperative input of sodium bicarbonate (P=0.019), input of red blood cell suspension (P=0.004), the input of blood plasma (P=0.043), intraoperative urine output (P=0.006), and preoperative creatinine (P=0.041) between the control and AKI group. Multivariate analysis indicated that chronic severe hepatitis (OR: 2.872; P=0.003) and preoperative creatinine (OR: 1.083; P=0.011) were independent risk factors for AKI in patients receiving liver transplantation.

Conclusions

Chronic severe hepatitis and preoperative creatinine may be potential risk factors for the occurrence of AKI after liver transplantation.

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

Background

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

Methods

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

Results

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

Conclusions

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

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

Background

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

Material/Methods

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

Results

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

Conclusions

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

Perioperative risk factors of progressive chronic kidney disease following liver transplantation: analyses of a 10-year follow-up single-center cohort

Purpose

The incidence of chronic kidney disease (CKD) has been increasing due to improved survival after liver transplantation (LT). Risk factors of kidney injury after LT, especially perioperative management factors, are potentially modifiable. We investigated the risk factors associated with progressive CKD for 10 years after LT.

Methods

This retrospective cohort study included 292 adult patients who underwent LT at a tertiary referral hospital between 2000 and 2008. Renal function was assessed by the e stimated glomerular filtration rate (eGFR) using the Modification of Diet in Renal Disease formula. The area under the curve of serial eGFR (AUC_eGFR) was calculated for each patient to assess the trajectory of eGFR over the 10 years. Low AUC_eGFR was considered progressive CKD. Linear regression analyses were performed to examine the associations between the variables and AUC_eGFR.

Results

Multivariable analysis showed that older age (regression coefficient = -0.53, P < 0.001), diabetes mellitus (DM) (regression coefficient = -6.93, P = 0.007), preoperative proteinuria (regression coefficient = -16.11, P < 0.001), preoperative acute kidney injury (AKI) (regression coefficient = -14.35, P < 0.001), postoperative AKI (regression coefficient = -3.86, P = 0.007), and postoperative mean vasopressor score (regression coefficient = -0.45, P = 0.034) were independently associated with progressive CKD.

Conclusion

More careful renoprotective management is required in elderly LT patients with DM or preexisting proteinuria. Postoperative AKI and vasopressor dose may be potentially modifiable risk factors for progressive CKD.

Association of overweight with postoperative acute kidney injury among patients receiving orthotopic liver transplantation: an observational cohort study

BACKGROUND

Acute kidney injury (AKI) is a common postoperative complication of orthotopic liver transplantation (OLT). So far, little attention has been paid on the association between overweight and AKI after OLT, and animal models or clinical studies have drawn conflicting conclusions. The objective of our study was to determine whether overweight (BMI [Body Mass Index] ≥ 25 kg/m2) is associated with an increased risk of AKI after OLT.

METHODS

This retrospective cohort study included 244 patients receiving OLT in the Affiliated Hospital of Qingdao University between January 1, 2017, and August 29, 2019. Preoperative, intraoperative, and postoperative data were collected retrospectively. The primary outcome was the development of AKI as defined by Kidney Disease, Improving Global Outcome (KIDGO) staging system. Logistic regression analysis was used to determine the relationship between overweight and the occurrence of postoperative AKI. Data analysis was conducted from September to October 2019, revision in April 2020.

RESULTS

Among 244 patients receiving OLT (mean [standard deviation] age, 54.1 [9.6] years; 84.0% male) identified, 163 patients (66.8%) developed postoperative AKI. Overweight (BMI ≥ 25 kg/m2) was associated with a higher rate of postoperative severe AKI (stage 2/3) compared with normal weight (18.5 ≤ BMI < 25 kg/m2) (41 [47.7%] vs 39 [28.7%]; adjusted odds ratio [OR], 2.539; 95% confidence interval [CI], 1.389-4.642; P = 0.002). Furthermore, patients with obese were at even higher risk of postoperative severe AKI after controlling for confounding factors (adjusted OR: 3.705; 95% CI: 1.108-12.388; P = 0.033).

CONCLUSIONS

Overweight is independently associated with an increased risk of postoperative severe AKI among patients receiving OLT. The association of BMI with severe AKI after OLT is J-shaped.

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.

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

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

Role of thrombocytopenia in risk stratification for acute kidney injury after living donor liver transplantation

The aim of our study was to investigate pre and intraoperative clinical factors, including platelet count, which could inform risk stratification of early acute kidney injury (AKI) after living donor liver transplantation (LDLT). Additionally, the impact of severe thrombocytopenia on AKI risk was assessed using a propensity score (PS)-matched analysis. In total, 591 adult patients who underwent LDLT between January 2009 and December 2018 at our hospital were retrospectively analyzed. Early postoperative AKI was determined based on the KDIGO criteria, and 149 patients (25.2%) developed AKI immediately after surgery. In a multivariate analysis, a lower preoperative platelet count was significantly associated with early postoperative AKI, together with diabetes mellitus, lower hourly urine output, and longer graft ischemic time; furthermore, a decrease in platelet count was correlated with AKI severity. After adjusting for the PS, the probability of AKI was significantly (1.9-fold) higher in patients with severe thrombocytopenia than in those without severe thrombocytopenia. Patients with thrombocytopenia showed a higher postoperative incidence of AKI and a higher requirement for dialysis than those without thrombocytopenia. The platelet count can easily be obtained via regular blood analysis of patients scheduled for LDLT and can be used to identify patients at risk for AKI.

Intraoperative Oxygen Delivery and Acute Kidney Injury after Liver Transplantation

Although intraoperative hemodynamic variables were reported to be associated with acute kidney injury (AKI) after liver transplantation, the time-dependent association between intraoperative oxygen delivery and AKI has not yet been evaluated. We reviewed 676 cases of liver transplantation. Oxygen delivery index (DO2I) was calculated at least ten times during surgery. AKI was defined according to the Kidney Disease Improving Global Outcomes criteria. The area under the curve (AUC) was calculated as below a DO2I of 300 (AUC < 300), 400 and 500 mL/min/m2 threshold. Also, the cumulative time below a DO2I of 300 (Time < 300), 400, and 500 mL/min/m2 were calculated. Multivariable logistic regression analysis was performed to evaluate whether AUC < 300 or time < 300 was independently associated with the risk of AKI. As a sensitivity analysis, propensity score matching analysis was performed between the two intraoperative mean DO2I groups using a cutoff of 500 ml/min/m2, and the incidence of AKI was compared between the groups. Multivariable analysis showed that AUC < 300 or time < 300 was an independent predictor of AKI (AUC < 300: odds ratio [OR] = 1.10, 95% confidence interval [CI] 1.06-1.13, time < 300: OR = 1.10, 95% CI 1.08-1.14). Propensity score matching yielded 192 pairs of low and high mean DO2I groups. The incidence of overall and stage 2 or 3 AKI was significantly higher in the lower DO2I group compared to the higher group (overall AKI: lower group, n = 64 (33.3%) vs. higher group, n = 106 (55.2%), P < 0.001). In conclusion, there was a significant time-dependent association between the intraoperative poor oxygen delivery <300 mL/min/m2 and the risk of AKI after liver transplantation. The intraoperative optimization of oxygen delivery may mitigate the risk of AKI.

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.

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.

Urinary [TIMP-2] × [IGFBP-7] for predicting acute kidney injury in patients undergoing orthotopic liver transplantation

BACKGROUND

The product of the concentrations of urinary tissue inhibitor of metalloproteinases-2 and insulin-like growth factor binding protein-7 (urinary [TIMP-2] × [IGFBP-7]) has been suggested as biomarker for early detection of acute kidney injury (AKI) in various clinical settings. However, the performance of urinary [TIMP-2] × [IGFBP-7] to predict AKI has never been assessed in patients undergoing orthotopic liver transplantation (OLT). Thus, the aim of this study was to assess the early predictive value of urinary [TIMP-2] × [IGFBP-7] for the development of AKI after OLT.

METHODS

In this observational study, urinary [TIMP-2] × [IGFBP-7] was measured in samples from adult OLT patients. AKI was diagnosed and classified according to KDIGO criteria. Areas under the receiver operating curves (AUC) were calculated to assess predictive values of urinary [TIMP-2] × [IGFBP-7] for the development of AKI.

RESULTS

Forty patients (mean age 55 ± 8 years) were included. Twenty-eight patients (70%) developed AKI stage 1, 2, or 3 within 48 h after OLT. Urinary [TIMP-2] × [IGFBP-7] was not predictive for AKI at the end of OLT (AUC: 0.54, CI [0.32-0.75], P = 0.72), at day 1 (AUC: 0.60, CI [0.41-0.79], P = 0.31), or day 2 after OLT (AUC: 0.63, CI [0.46-0.8], P = 0.18).

CONCLUSION

Based on our results, routine clinical use of urinary [TIMP-2] × [IGFBP-7] cannot be recommended for risk assessment of AKI in patients undergoing OLT.

Urinary and Serum Biomarkers for Prediction of Acute Kidney Injury in Patients Undergoing Liver Transplantation

Acute kidney injury (AKI) is a frequent and serious complication of orthotopic liver transplantation (OLT), with a significant impact on mortality, graft survival, and chronic kidney disease. Currently, the diagnosis of AKI is based on changes in serum creatinine, which is a late marker, usually rising when there is already significant damage to the renal parenchyma. During the last 2 decades, various biomarkers have been studied in many clinical situations, mostly after cardiac surgery, in drug-induced AKI, or in sepsis. The present article summarizes the data on those biomarkers that have been evaluated for the prediction of AKI in patients undergoing OLT.

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 Postoperative Acute Kidney Injury Among Pediatric Liver Transplant Recipients

OBJECTIVES

Acute kidney injury after pediatric liver transplant is associated with increased morbidity and mortality. Here, we evaluated children with acute kidney injury early posttransplant using KDIGO criteria to determine incidence, risk factors, and clinical outcomes.

MATERIALS AND METHODS

In this retrospective cohort study, medical records of all patients < 16 years old who underwent liver transplant from April 2007 to April 2017 were reviewed.

RESULTS

Of 117 study patients, 69 (59%) were male and median age at transplant was 72 months (range, 12-120 mo). Forty children (34.2%) had postoperative acute kidney injury, with most having stage 1 disease (n = 21). Compared with children who had acute kidney injury versus those who did not, preoperative activated partial thromboplastin time (median 35.6 s [interquartile range, 32.4-42.8 s] vs 42.5 s [interquartile range, 35-49 s]; P = .007), intraoperative lactate levels at end of surgery (median 5.3 mmol/L [interquartile range, 3.3-8.6 mmol/L] vs 7.9 mmol/L [interquartile range, 4.3-11.2 mmol/L]; P = .044), and need for open abdomen (3% vs 15%; P= .024) were significantly higher. Logistic regression analysis revealed that preoperative high activated partial thromboplastin time (P= .02), intraoperative lactate levels at end of surgery (P = .02), and need for open abdomen (P = .03) were independent risk factors for acute kidney injury. Children who developed acute kidney injury had significantly longer intensive care unit stay (7.1 ± 8.5 vs 4.4 ± 5.4 days, P= .04) and mortality (12.8% vs 1.8%; P = .01).

CONCLUSIONS

Early postoperative acute kidney injury occurred in 34.2% of pediatric liver transplant recipients, with patients having increased mortality risk. High preoperative activated partial throm-boplastin time, high intraoperative end of surgery lactate levels, and need for open abdomen were shown to be associated with acute kidney injury after pediatric liver transplant.

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.

Prediction of Acute Kidney Injury after Liver Transplantation: Machine Learning Approaches vs. Logistic Regression Model

Acute kidney injury (AKI) after liver transplantation has been reported to be associated with increased mortality. Recently, machine learning approaches were reported to have better predictive ability than the classic statistical analysis. We compared the performance of machine learning approaches with that of logistic regression analysis to predict AKI after liver transplantation. We reviewed 1211 patients and preoperative and intraoperative anesthesia and surgery-related variables were obtained. The primary outcome was postoperative AKI defined by acute kidney injury network criteria. The following machine learning techniques were used: decision tree, random forest, gradient boosting machine, support vector machine, naïve Bayes, multilayer perceptron, and deep belief networks. These techniques were compared with logistic regression analysis regarding the area under the receiver-operating characteristic curve (AUROC). AKI developed in 365 patients (30.1%). The performance in terms of AUROC was best in gradient boosting machine among all analyses to predict AKI of all stages (0.90, 95% confidence interval [CI] 0.86–0.93) or stage 2 or 3 AKI. The AUROC of logistic regression analysis was 0.61 (95% CI 0.56–0.66). Decision tree and random forest techniques showed moderate performance (AUROC 0.86 and 0.85, respectively). The AUROC of support the vector machine, naïve Bayes, neural network, and deep belief network was smaller than that of the other models. In our comparison of seven machine learning approaches with logistic regression analysis, the gradient boosting machine showed the best performance with the highest AUROC. An internet-based risk estimator was developed based on our model of gradient boosting. However, prospective studies are required to validate our results.

Critical Care Management of Living Donor Liver Transplants

This article represents a review of the postoperative management of donors and recipients after living donor liver transplant, including monitoring, liberation from mechanical ventilation, nutritional support, and pain control. Vascular complications, such as biliary and sepsis, and bleeding are also discussed. Finally, commonly used immunosuppression and antimicrobial prophylaxes are reviewed.

Acute Kidney Injury Before and After Liver Transplant

The development of acute kidney injury in the setting of liver disease is a significant event both before and after liver transplant. Whether acute kidney injury is the cause of or merely associated with worse outcomes, the development of renal failure is significant from a prognostic as well as from a diagnostic and therapeutic standpoint. Although not every etiology is reversible, there are number of etiologies that are correctable, to include hypovolemia, nephrotoxic medications, and acute tubular necrosis. In the post-liver transplant period, renal failure is associated with graft failure as well as worse outcomes overall. Prompt recognition, workup, and intervention can significantly impact outcomes and survival both before and after liver transplant.

Update on perioperative acute kidney injury

PURPOSE OF REVIEW

In this review, we discuss the latest updates on perioperative acute kidney injury (AKI) and the specific considerations that are relevant to different surgeries and patient populations.

RECENT FINDINGS

AKI diagnosis is constantly evolving. New biomarkers detect AKI early and shed a light on the possible cause of AKI. Hypotension, even for a short duration, is associated with perioperative AKI. The debate on the deleterious effects of chloride-rich solutions is still far from conclusion. Remote ischemic preconditioning is showing promising results in the possible prevention of perioperative AKI. No definite data show a beneficiary effect of statins, fenoldepam, or sodium bicarbonate in preventing AKI.

SUMMARY

Perioperative AKI is prevalent and associated with significant morbidity and mortality. Considering the lack of effective preventive or therapeutic interventions, this review focuses on perioperative AKI: measures for early diagnosis, defining risks and possible mechanisms, and summarizing current knowledge for intraoperative fluid and hemodynamic management to reduce risk of AKI.

Risk Analysis for Invasive Fungal Infection after Living Donor Liver Transplantation: Which Patient Needs Potent Prophylaxis?

BACKGROUND

Invasive fungal infection (IFI) is associated with high mortality after living donor liver transplant (LDLT). The aim of this study was to identify the risk factors for post-LDLT IFI for early diagnosis and improvement of antifungal treatment outcome.

METHODS

Risk analysis data were available for all 153 patients who underwent LDLT between January 2005 and April 2012.

RESULTS

During the follow-up period (1,553 ± 73 days, range 20-2,946 days), 15 patients (9.8%) developed IFI classified as "proven" (n = 8) and "probable" (n = 7) with fungal pathogens including Candida spp. (n = 10), Aspergillus spp. (n = 4), and Trichosporon (n = 2). Of these patients, 7 patients with IFI died despite treatment. The 1-, 3-, and 5-year survival rates were lower in patients with IFI than those without IFI (66.7/59.3/44.4 vs. 90.4/85.7/81.8%, respectively; p = 0.0026). Multivariate analysis identified model for end-stage liver disease score of ≥26 (OR 16.0, p = 0.0012) and post-transplant acute kidney injury (RIFLE criteria I- or F-class; OR 4.87, p = 0.047) as independent risk factors for IFI.

CONCLUSION

Preoperative recipients' status and postoperative kidney dysfunction can affect an occurrence of post-transplant IFI. These risk factors would be taken into consideration for designation of proper antifungal therapy.

Comparison of macrophage migration inhibitory factor and neutrophil gelatinase-associated lipocalin-2 to predict acute kidney injury after liver transplantation: An observational pilot study

Introduction

Several biomarkers have been suggested as early predictors of acute kidney injury (AKI) after orthotopic liver transplantation (OLT). Neutrophil gelatinase-associated lipocalin-2 (NGAL) appears to be a promising predictor of AKI after OLT, but the clinical benefit remains to be proven. Recently, systemic macrophage migration inhibitory factor (MIF) has been proposed as early indicator for requirement of renal replacement therapy after OLT. The aim of this prospective, observational pilot study was to compare the predictive values of serum and urinary MIF for severe AKI after OLT to those of serum and urinary NGAL.

Methods

Concentrations of MIF and NGAL were measured in serum and urine samples collected from patients undergoing OLT. Acute kidney injury was classified according to the KDIGO criteria, with stages 2 and 3 summarized as severe AKI. Areas under the receiver operating curves (AUC) were calculated to assess predictive values of MIF and NGAL for the development of severe AKI.

Results

Forty-five patients (mean age 55±8 years) were included. Nineteen patients (38%) developed severe AKI within 48 hours after reperfusion. At the end of OLT, serum MIF was predictive of severe AKI (AUC 0.73; 95% confidence intervals, CI 0.55–0.90; P = 0.03), whereas urinary MIF, serum NGAL, and urinary NGAL were not. On the first postoperative day, serum MIF (AUC 0.78; CI 0.62–0.93; P = 0.006), urinary MIF (AUC 0.71; CI 0.53–0.88; P = 0.03), and urinary NGAL (AUC 0.79; CI 0.64–0.93; P = 0.02) were predictive for severe AKI, while serum NGAL was not.

Conclusion

In the setting of OLT, MIF and NGAL had similar predictive values for the development of severe AKI.