Early acute kidney injury after liver transplantation in patients with normal preoperative renal function

Optimization and Protection of Kidney Health in Liver Transplant Recipients: Intra- and Postoperative Approaches

Postoperative acute kidney injury after liver transplant (LT) has long-term implications for kidney health. LT recipients are at risk of acute kidney injury due to a number of factors related to the donor liver, intraoperative factors including surgical technique, as well as recipient factors, such as pre-LT kidney function and postoperative complications. This review discusses these factors in detail and their impact on posttransplant kidney function. Long-term risk factors such as calcineurin inhibitors have also been discussed. Additionally, the impact of liver allocation policies on pre- and post-LT kidney health is discussed.

Early predictors of prolonged intensive care utilization following liver transplantation

INTRODUCTION

Creatinine, bilirubin, and fibrinolysis resistance are associated with multi-organ dysfunction and likely risk factors for prolonged intensive care unit (pICU) stay following liver transplantation (LT). We hypothesize postoperative day-1 (POD-1) labs will predict pICU.

METHODS

LT recipients had clinical laboratories and viscoelastic testing with tissue plasminogen activator thrombelastography (tPA TEG) to quantify fibrinolysis resistance (LY30) on POD-1. pICU was defined as one week or longer in the ICU. Logistic regression was used to identify the relationship between POD-1 labs and pICU.

RESULTS

Of 304 patients, 50% went to the ICU, with 15% experiencing pICU. Elevated creatinine (OR 6.6, P ​< ​0.001) and low tPA TEG LY30 (OR 3.7, P ​= ​0.004) were independent predictors of pICU after controlling for other risk factors. A 9-fold increase in the rate of 90-day graft loss (19% vs 2% p ​< ​0.001) was observed patients who had these risk factors for pICU.

CONCLUSION

Elevated creatine and fibrinolysis resistance are associated with pICU and poor outcomes following LT.

Development of a nomogram for the prediction of acute kidney injury after liver transplantation: a model based on clinical parameters and postoperative cystatin C level

BACKGROUND

Acute kidney injury (AKI) is common after liver transplantation (LT). We developed a nomogram model to predict post-LT AKI.

METHODS

A total of 120 patients were eligible for inclusion in the study. Clinical information was extracted from the institutional electronic medical record system. Blood samples were collected prior to surgery and immediately after surgery. Univariable and multivariate logistic regression were used to identify independent risk factors. Finally, a nomogram was developed based on the final multivariable logistic regression model.

RESULTS

In total, 58 (48.3%) patients developed AKI. Multivariable logistic regression revealed four independent risk factors for post-LT AKI: operation duration [odds ratio (OR) = 1.728, 95% confidence interval (CI) = 1.121-2.663, p = 0.013], intraoperative hypotension (OR = 3.235, 95% CI = 1.316-7.952, p = 0.011), postoperative cystatin C level (OR = 1.002, 95% CI = 1.001-1.004, p = 0.005) and shock (OR = 4.002, 95% CI = 0.893-17.945, p = 0.070). Receiver operating characteristic curve analysis was used to evaluate model discrimination. The area under the curve value was 0.815 (95% CI = 0.737-0.894).

CONCLUSION

The model based on combinations of clinical parameters and postoperative cystatin C levels had a higher predictive performance for post-LT AKI than the model based on clinical parameters or postoperative cystatin C level alone. Additionally, we developed an easy-to-use nomogram based on the final model, which could aid in the early detection of AKI and improve the prognosis of patients after LT.

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.

Postoperative Blood Pressure Deficit and Acute Kidney Injury After Liver Transplant

OBJECTIVES

Acute kidney injury is a common cause of morbidity in liver transplant recipients. In critically ill patients who received an orthotopic liver transplant, we examined whether those with acute kidney injury had a greater deficit between pretransplant and posttransplant hemodynamic pressure-related parameters compared with those without acute kidney injury in the early postoperative period.

MATERIALS AND METHODS

We included patients who underwent an orthotopic liver transplant during the study period. We obtained premorbid and intensive care unit time-weighted average values for hemodynamic pressure-related parameters (systolic, diastolic, and mean arterial pressure; central venous pressure; mean perfusion pressure; and diastolic perfusion pressure) and calculated deficits in those values. We defined acute kidney injury progression as an increase of ≥1 Kidney Disease: Improving Global Outcomes stage.

RESULTS

We included 150 eligible transplantrecipients, with 88 (59%) having acute kidney injury progression. Acute kidney injury was associated with worse clinical outcomes. All achieved pressure-related values were similar between transplant recipients with or without acute kidney injury progression. However, those with acute kidney injury versus those without progression had greater diastolic perfusion pressure deficit at 12 hours (-8.33% vs 1.93%; P = .037) and 24 hours (-7.38% vs 5.11%; P = .002) and increased central venous pressure at 24 hours (46.13% vs 15%; P = .043) and 48 hours (40% vs 20.87%; P = .039).

CONCLUSIONS

Patients with acute kidney injury progression had a greater diastolic perfusion pressure deficit and increased central venous pressure compared with patients without progression. Such deficits might be modifiable risk factors for the prevention of acute kidney injury progression.

Are short-term complications associated with poor allograft and patient survival after liver transplantation? A systematic review of the literature and expert panel recommendations

BACKGROUND

Maximizing patient and allograft survival after liver transplant (LT) is important from both a patient care and organ utilization perspective. Although individual studies have addressed the effects of short-term post-LT complications on a limited scale, there has not been a systematic review of the literature formally assessing the potential effects of early complications on long-term outcomes.

OBJECTIVES

To identify whether short-term complications after LT affect allograft and overall survival, to identify short-term complications of particular clinical interest and significance, and to provide recommendations to improve post-LT graft and patient survival.

DATA SOURCES

Ovid MEDLINE, Embase, Scopus, Google Scholar, and Cochrane Central.

METHODS

A systematic review following PRISMA guidelines and recommendations using the GRADE approach derived from an international expert panel.

RESULTS

The literature review and analysis provided show that short-term complications have a large impact on allograft and patient survival after LT. The complications with the strongest effect on survival are acute kidney injury (AKI), biliary complications, and early allograft dysfunction (EAD).

CONCLUSION

This panel recommends taking measures to reduce the risk and incidence of short-term complications post-LT. Clinicians should pay particular attention to preventing or ameliorating AKI, biliary complications, and EAD (Quality of evidence; Moderate | Grade of Recommendation; Strong).

Hepatorenal Syndrome and Other Post-Liver Transplantation Complications: Case Studies and Literature Review

Hepatorenal syndrome (HRS) was originally defined as a renal dysfunction caused by a decreased renal perfusion due to hemodynamic disturbances in the arterial circulation and an excessive activity of endogenous vasoactive systems in the course of cirrhosis. Considering the latest research, this syndrome may have a more complex pathomechanism. Equally often as in cirrhosis, HRS develops after orthotopic liver transplantation (OLTx) and worsens the prognosis significantly increasing mortality rates in this patient population. The prevalence of renal complications after OLTx and their negative prognostic impact on the survival of both the graft and the recipient prompted the authors of this work to analyze in detail 2 cases of HRS after OLTx to indicate the multiplicity of factors contributing to the pathophysiology of this syndrome. Attention was paid to risk factors for HRS found in the anamnesis before OLTx, especially a pre-existing renal dysfunction. In both cases early post-OLTx complications associated with the transplantation procedure were described: destabilization of the circulatory system, transfusions of blood products, prolonged stay at an intensive care unit, and necessity of introducing continuous renal replacement therapy. In the later period after the OLTx, infections (bacterial, fungal, viral) and drug nephrotoxicity, including the activity of immunosuppressants (tacrolimus), contributed primarily to the renal function impairment.

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.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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 ).

Patient blood management in India - Review of current practices and feasibility of applying appropriate standard of care guidelines. A position paper by an interdisciplinary expert group

In a developing country like India, with limited resources and access to healthcare facilities, dealing with massive hemorrhage is a major challenge. This challenge gets compounded by pre-existing anemia, hemostatic disorders, and logistic issues of timely transfer of such patients from peripheral hospitals to centers with adequate resources and management expertise. Despite the awareness amongst healthcare providers regarding management modalities of bleeding patients, no uniform Patient Blood Management (PBM) or perioperative bleeding management protocols have been implemented in India, yet. In light of this, an interdisciplinary expert group came together, comprising of experts working in transfusion medicine, hematology, obstetrics, anesthesiology and intensive care, to review current practices in management of bleeding in Indian healthcare institutions and evaluating the feasibility of implementing uniform PBM guidelines. The specific intent was to perform a gap analysis between the ideal and the current status in terms of practices and resources. The expert group identified interdisciplinary education in PBM and bleeding management, bleeding history, viscoelastic and platelet function testing, and the implementation of validated, setting-specific bleeding management protocols (algorithms) as important tools in PBM and perioperative bleeding management. Here, trauma, major surgery, postpartum hemorrhage, cardiac and liver surgery are the most common clinical settings associated with massive blood loss. Accordingly, PBM should be implemented as a multidisciplinary and practically applicable concept in India in a timely manner in order to optimize the use the precious resource blood and to increase patients' safety.

PI3K/AKT activation attenuates acute kidney injury following liver transplantation by inducing FoxO3a nuclear export and deacetylation

AIMS

Acute kidney injury (AKI) is a severe complication of autologous orthotopic liver transplantation (AOLT). Apoptosis has been shown to be involved in renal ischemia/reperfusion, and the PI3K/AKT signaling pathway is involved in numerous cell processes, including promoting cell survival and inhibiting apoptosis. We aimed to verify whether the PI3K/AKT signaling pathway participates in the development of post-AOLT AKI.

METHODS

Male Sprague-Dawley rats underwent AOLT with or without treatment with insulin-like growth factor-1 (IGF-1, a PI3K/AKT activator) and LY294002 (a PI3K/AKT inhibitor; n = 8/group). NRK-52E cells (rat renal tubular epithelial cell line) were subjected to hypoxia-re-oxygenation to mimic renal cell I/R injury in vitro, and confirm whether silencing information regulator 1 (SIRT1) mediated the protective effects of PI3K/AKT by deacetylating forkhead protein O3a (FoxO3a).

KEY FINDINGS

During the reperfusion stage, kidney injury peaked at 8 h after reperfusion, then gradually recovered, which was consistent with the dynamic changes in apoptosis and the protein expressions of Bcl-2 interacting mediator of cell death (Bim), Fas ligand (FasL), and nuclear FoxO3a AKT phosphorylation and nuclear SIRT1 protein expression were also upregulated. IGF-1 application decreased Bim, FasL, and nuclear FoxO3a protein expressions, and protected against apoptosis and AKI. In NRK-52E cells, IGF-1 upregulated nuclear SIRT1 expression, reduced FoxO3a acetylation, downregulated Bim and FasL protein expressions, and attenuated apoptosis and AKI; these effects were reversed by SIRT1 blocking.

CONCLUSION

The activation of the PI3K/AKT signaling pathway not only induced FoxO3a nuclear export but also deacetylation through upregulating nuclear SIRT1 expression to attenuate post-AOLT AKI.

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.

Peri-transplant management of nonalcoholic fatty liver disease in liver transplant candidates

The incidence of non-alcoholic fatty liver disease (NAFLD) is rapidly growing, affecting 25% of the world population. Non-alcoholic steatohepatitis (NASH) is the most severe form of NAFLD and affects 1.5% to 6.5% of the world population. Its rising incidence will make end-stage liver disease (ESLD) due to NASH the number one indication for liver transplantation (LT) in the next 10 to 20 years, overtaking Hepatitis C. Patients with NASH also have a high prevalence of associated comorbidities such as type 2 diabetes, obesity, metabolic syndrome, cardiovascular disease, and chronic kidney disease (CKD), which must be adequately managed during the peritransplant period for optimal post-transplant outcomes. The focus of this review article is to provide a comprehensive overview of the unique challenges these patients present in the peritransplant period, which comprises the pre-transplant, intraoperative, and immediate postoperative periods.