Postreperfusion microcirculatory derangements after liver transplantation: Relationship to hemodynamics, serum mediators, and outcome

Liver transplantation with interposition saphenous vein conduits for arterial reconstruction: Impact of morbidity and arterial ischemia time

BACKGROUND

The outcomes of liver transplantation with hepatic arterial reconstruction using interposition saphenous vein conduits are not widely reported. Here, we share our experience using great saphenous vein conduits for hepatic arterial reconstruction in living donor liver transplantation.

METHODS

This was a single-center retrospective review of patients who underwent living donor liver transplantation (n = 950). The saphenous vein conduits were used in 39 patients. We compared hepatic artery thrombosis, graft dysfunction, and 30-day and 1-year survival in the early (2012-2017) and late (2017-2020) transplant periods.

RESULTS

Among 39 patients (of whom 30 [76.9%] were males, median Model for End-Stage Liver Disease was 24 [interquartile range, 17-27], median age was 50 [interquartile range, 43-54]), saphenous vein conduits were placed on supra celiac aorta in 7 (17.9%), infrarenal aorta in 25 (64.1%), and other arteries in 7 (17.9%) patients. The number of biliary and hepatic vein anastomoses, total arterial ischemia time, portal vein-hepatic artery reperfusion time, and duration of surgery was different in the 2 groups (P < .05). The 30-day mortality was 5/21 (23.8%) and 0 in the early and late periods (P = .05). The 30-day survival was >90% in patients with portal vein-hepatic artery reperfusion time <240 minutes, ≤2 grade 3 complications, no graft dysfunction, and later period of transplantation (P < .05). The 1-year survival with standard transplantation, transplantation with saphenous vein conduits in the early and late period was 87%, 62%, and 89% (P = .022).

CONCLUSION

Liver transplantation with saphenous vein conduits is associated with acceptable outcomes. Major complications and arterial ischemia times are major determinants of outcomes.

[Application Value of Novel Coagulation Markers in Predicting Postoperarative Complications in the Early Stage After Liver Transplantation]

Objective

To investigate the relationship between thrombin-antithrombin complex (TAT), plasmin-α 2-plasmininhibitor complex (PIC), soluble thrombomodulin (sTM), and tissue plasminogen activator-inhibitor complex (tPAIC) and postoperative complications in the early stage after liver transplantation (LT).

Methods

We analyzed the perioperative clinical data, including plasma TAT, PIC, sTM, and tPAIC, of 130 post-LT patients admitted to the intensive care unit (ICU), West China Hospital, Sichuan University between December 2021 and November 2022. Patients were divided into two groups, a complication group and a non-complication group, according to whether they experienced complications of Clavien-Dindo (CD) grade Ⅲb and above within 30 days after the surgery. Univariate analysis and binary multivariate logistic regression models were used to determine the risk factors for complications within 30 days post-LT.

Results

The incidence of complications of CD grade Ⅲb and above within 30 days post-LT was 33.1% (43/130). Patients in the complication group had significantly higher scores for the Model for End-Stage Liver Disease (MELD), operative time, intraoperative red blood cell transfusion volume, intraoperative plasma transfusion volume, and plasma TAT, PIC, sTM and tPAIC measured at the time of admission to ICU after the operation than those in the non-complication group did (all P<0.05). Logistic regression showed that for every single U of red blood cells transfused during the transplant surgery, the probabilities of complications within 30 days post-LT increased by 15.1% (95% confidence interval [ C I]: 1.070-1.239, P<0.001) and for the increase of every single TU/mL of plasma sTM measured upon post-LT admission to ICU, the probabilities of complications increased by 13.7% (95% CI: 1.060-1.220, P<0.001).

Conclusion

Plasma sTM measured upon admission to ICU after LT is an independent risk factor for complications within 30 days post-LT, and additional assessment of sTM may help predict complications in the early stage post-LT.

Microneedle array facilitates hepatic sinusoid construction in a large-scale liver-acinus-chip microsystem

Hepatic sinusoids play a key role in maintaining high activities of liver cells in the hepatic acinus. However, the construction of hepatic sinusoids has always been a challenge for liver chips, especially for large-scale liver microsystems. Herein, we report an approach for the construction of hepatic sinusoids. In this approach, hepatic sinusoids are formed by demolding a self-developed microneedle array from a photocurable cell-loaded matrix in a large-scale liver-acinus-chip microsystem with a designed dual blood supply. Primary sinusoids formed by demolded microneedles and spontaneously self-organized secondary sinusoids can be clearly observed. Benefiting from significantly enhanced interstitial flows by formed hepatic sinusoids, cell viability is witnessed to be considerably high, liver microstructure formation occurs, and hepatocyte metabolism is enhanced. In addition, this study preliminarily demonstrates the effects of the resulting oxygen and glucose gradients on hepatocyte functions and the application of the chip in drug testing. This work paves the way for the biofabrication of fully functionalized large-scale liver bioreactors.

Microvascular Leakage as Therapeutic Target for Ischemia and Reperfusion Injury

Reperfusion injury is a very common complication of various indicated therapies such as the re-opening of vessels in the myocardium or brain as well as reflow in hemodynamic shutdown (cardiac arrest, severe trauma, aortic cross-clamping). The treatment and prevention of reperfusion injury has therefore been a topic of immense interest in terms of mechanistic understanding, the exploration of interventions in animal models and in the clinical setting in major prospective studies. While a wealth of encouraging results has been obtained in the lab, the translation into clinical success has met with mixed outcomes at best. Considering the still very high medical need, progress continues to be urgently needed. Multi-target approaches rationally linking interference with pathophysiological pathways as well as a renewed focus on aspects of microvascular dysfunction, especially on the role of microvascular leakage, are likely to provide new insights.

In silico modeling for the hepatic circulation and transport: From the liver organ to lobules

The function of the liver depends critically on its blood supply. Numerous in silico models have been developed to study various aspects of the hepatic circulation, including not only the macro-hemodynamics at the organ level, but also the microcirculation at the lobular level. In addition, computational models of blood flow and bile flow have been used to study the transport, metabolism, and clearance of drugs in pharmacokinetic studies. These in silico models aim to provide insights into the liver organ function under both healthy and diseased states, and to assist quantitative analysis for surgical planning and postsurgery treatment. The purpose of this review is to provide an update on state-of-the-art in silico models of the hepatic circulation and transport processes. We introduce the numerical methods and the physiological background of these models. We also discuss multiscale frameworks that have been proposed for the liver, and their linkage with the large context of systems biology, systems pharmacology, and the Physiome project. This article is categorized under: Metabolic Diseases > Computational Models Metabolic Diseases > Biomedical Engineering Cardiovascular Diseases > Computational Models.

Does Arterialization of Portal Vein Have Any Effects in Large-for-Size Liver Transplantation? Hemodynamic, Histological, and Biomolecular Experimental Studies

BACKGROUND

In pediatric liver transplantation, the optimal size of the transplanted liver ranges between 0.8% and 4.0% of the recipient's weight. Sometimes, the graft weight exceeds this upper limit, characterizing the large-for-size condition potentially associated with reduced blood flow and worsening of ischemia-reperfusion injury. Therefore, it would be beneficial to increase the portal flow through arterialization of the portal vein. Materials and methods: Fifteen pigs underwent large-for-size liver transplants. They were divided into two groups: control (CTRL 6 animals - conventional technique) and arterialization - a shunt was established between the portal vein and the splenic artery (ART 9 animals). Hemodynamic, biochemical, histological, and molecular variables were compared. Results: Arterialization resulted in a significant increase in portal vein pressure but no changes in other hemodynamic variables, as shown in the analysis of variance. It was observed lower ALT values (p = 0.007), with no differences regarding the values of blood pH and lactate (p = 0.54 and p = 0.699 respectively) or histological variables (edema, steatosis, inflammation, necrosis, and IRI - p = 1.0, p = 0.943, p = 0.174, p = 0.832, p = 0.662, respectively). The molecular studies showed significantly increased expression of IL6 after 3 hours of reperfusion (p = 0.048) and decreased expression of ICAM immediately after reperfusion (p = 0.03). The regression analysis suggested a positive influence of portal flow and pressure on biochemical parameters. Conclusion: Arterialization of the portal vein showed no histological, biochemical, or molecular benefits in large-for-size transplantation.

Effects of Initial Hepatic Artery Followed by Portal Reperfusion Technique on Deceased Donor Liver Transplant Outcomes

OBJECTIVES

Although initial portal vein reperfusion of a liver allograft is nearly standardized, limited data suggest initial hepatic artery reperfusion may improve hemodynamics and posttransplant outcomes.

MATERIALS AND METHODS

We retrospectively reviewed orthotopic liver transplants performed between January 2013 and February 2018. Parameters of liver recipients with initial hepatic artery reperfusion were compared with those with initial portal vein reperfusion.

RESULTS

Of 204 recipients, 53 (26%) were initially perfused from the hepatic artery and 151 (74%) were initially perfused from the portal vein. Demographics between groups did not differ. There were no significant differences in the incidence of acute rejection between recipients with initial hepatic artery reperfusion versus portal vein reperfusion at 3 months and 1 year (1.9% vs 7.9% and 7.5% vs 10.6%; not significant), hepatic artery thrombosis (1.9% vs 4.0% and 1.9% vs 7.3%; not significant), biliary leakage (7.5% vs 4.0% and 9.4 vs 6.6; not significant), biliary strictures (7.5% vs 5.3% and 11.3% vs 7.9%; not significant), or portal or hepatic venous thrombosis/stenosis (5.7% vs 5.3% and 7.5% vs 7.9%; not significant). Furthermore, recipients with initial hepatic artery reperfusion and portal vein reperfusion were both hospitalized for a median of 8.5 days (interquartile range, 6.5-15.5 vs 7.0-14.0 days, respectively), and both groups were in the intensive care unit for a median of 3 days (interquartile range, 2-7 vs 2-4 days, respectively). Initial hepatic artery reperfusion was associated with significantly less intraoperative packet red blood cell transfusion (median, 11.9 U [interquartile range, 11.1-13.1 U] vs 15.5 U [interquartile range, 12.9-17.9 U]; P < .001). The 2 groups did not differ in terms of patient and graft survival.

CONCLUSIONS

Initial reperfusion of liver allografts with arterial, rather than portal, blood has benefits to hemodynamic stability, did not have deleterious effects on outcomes, and resulted in less intraoperative blood utilization.

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.

Etiology of Liver Steatosis Influences the Severity of Ischemia/Reperfusion Injury and Survival After Liver Transplantation in Rats

Liver steatosis is a leading cause of graft disposal in liver transplantation, though the degree of steatosis is often the single factor determining acceptability of the graft. We investigated how the cause of liver steatosis affects graft function in rat orthotopic liver transplantation (OLT). OLT was performed using 2 types of steatotic liver grafts: the fasting and hyperalimentation (FHA) model and the methionine- and choline-deficient diet models. The FHA and 4-week feeding of a methionine- and choline-deficient diet (MCDD4wk) groups showed similar liver triglyceride levels without signs of steatohepatitis. Therefore, the 2 groups were compared in the following experiment. With 6-hour cold storage, the 7-day survival rate after OLT was far worse in the FHA than in the MCDD4wk group (0% versus 100%, P = 0.002). With 1-hour cold storage, the FHA group showed higher aspartate aminotransferase and alanine aminotransferase levels and histological injury scores in zones 1 and 2 at 24 hours after reperfusion than the normal liver and MCDD4wk groups. Intrahepatic microcirculation and tissue adenosine triphosphate levels were significantly lower in the FHA group after reperfusion. Hepatocyte necrosis, sinusoidal endothelial cell injury, and abnormal swelling of the mitochondria were also found in the FHA group after reperfusion. Tissue malondialdehyde levels were higher in the MCDD4wk group before and after reperfusion. However, the grafts up-regulated several antioxidant enzymes soon after reperfusion. Even though the degree of steatosis was equivalent, the 2 liver steatosis models possessed quite unique basal characteristics and showed completely different responses against ischemia/reperfusion injury and survival after transplantation. Our results demonstrate that the degree of fat accumulation is not a single determinant for the usability of steatotic liver grafts.

Protein Profiles of Pretransplant Grafts Predict Early Allograft Dysfunction After Liver Transplantation From Donation After Circulatory Death

BACKGROUND

Predicting the development of early allograft dysfunction (EAD) following liver transplantation (LT) remains challenging for transplant clinicians. The objectives of this study are to investigate the potential relationship between the protein profiles of pretransplant grafts and the onset of EAD, and then combine with clinical parameters to construct a mathematically predictive model.

METHODS

Clinical data of 121 LT procedures from donation after circulatory death at the authors' center were analyzed. The expression levels of 7 studied proteins were determined by immunohistochemistry. Another independent cohort of 37 subjects was designed for further validation of the predictive model.

RESULTS

With an incidence of 43.0% (52/121), EAD was linked to significantly increased risk of acute kidney injury and renal replacement therapy, as well as reduced 6-month patient and liver graft survival. Allograft weight and high intrahepatic vascular endothelial growth factor (VEGF) expression were identified as independent risk factors of EAD and survival outcomes. Liver grafts with high VEGF expression exhibited delayed functional recovery within the first postoperative week. The combination of VEGF overexpression and EAD yielded the highest frequency of renal dysfunction and the worst survival. Based on allograft weight and intrahepatic VEGF expression, an EAD risk assessment model was developed. The incidence of EAD differed significantly between grafts with risk scores ≥-1.72 and <-1.72. The model functioned well in the validation cohort.

CONCLUSIONS

Pretransplant intrahepatic protein profiling contributes to the estimation of early graft performance and recipient outcomes following LT. The predictive model could allow for an accurate prediction of EAD.

Intraoperative Imaging Techniques to Visualize Hepatic (Micro)Perfusion: An Overview

The microcirculation plays a crucial role in the distribution of perfusion to organs. Studies have shown that microcirculatory dysfunction is an independent predictor of morbidity and mortality. Hence, assessment of liver perfusion offers valuable information on the (patho)physiological state of the liver. The current review explores techniques in perfusion imaging that can be used intraoperatively. Available modalities include dynamic contrast-enhanced ultrasound, handheld vital microscopes, indocyanine green fluorescence angiography, and laser contrast speckle imaging. Dynamic contrast-enhanced ultrasound relays information on deep tissue perfusion and is a commonly used technique to assess tumor perfusion. Handheld vital microscopes provide direct visualization of the sinusoidal architectural structure of the liver, which is a unique feature of this technique. Intraoperative fluorescence imaging uses indocyanine green, a dye that is administered intravenously to visualize microvascular perfusion when excited using near-infrared light. Laser speckle contrast imaging produces non-contact large surface-based tissue perfusion imaging free from movement- or pressure-related artefacts. In this review, we discuss the intrinsic advantages and disadvantages of these techniques and their clinical and/or scientific applications.

Does graft hemodynamics affect the risk of hepatocellular carcinoma recurrence after liver transplantation?

Although experimental studies have reported that hepatic ischemia-reperfusion injury promotes tumor growth and metastases, the impact of graft hemodynamics on the recurrence of hepatocellular carcinoma (HCC) after liver transplantation (LT) is unclear. To investigate the association between graft hemodynamics and HCC recurrence after LT, we conducted a retrospective analysis of 279 patients who underwent LT for HCC. Graft hemodynamics including portal vein flow (PVF), hepatic artery flow (HAF), and total hepatic flow (THF) was analyzed as a predictor of HCC recurrence, using competing risk regression analyses. The cutoff values of PVF, HAF, and THF were set at the lower quartile of distribution. A cumulative recurrence curve demonstrated that low THF (<1511 mL/min, P = .005) was significantly associated with increased recurrence, whereas neither low PVF (<1230 mL/min, P = .150) nor low HAF (<164 mL/min, P = .110) was significant. On multivariate analysis, outside Milan criteria (sub-hazard ratio [SHR] = 3.742; P < .001), microvascular invasion (SHR = 3.698; P < .001), and low THF (SHR = 2.359; P = .010) were independently associated with increased HCC recurrence. In conclusion, our findings suggest that graft hemodynamics may play an important role in HCC recurrence after LT.

Interpatient heterogeneity in hepatic microvascular blood flow during vascular inflow occlusion (Pringle manoeuvre)

BACKGROUND

Vascular inflow occlusion (VIO) during liver resections (Pringle manoeuvre) can be applied to reduce blood loss, however may at the same time, give rise to ischemia-reperfusion injury (IRI). The aim of this study was to assess the characteristics of hepatic microvascular perfusion during VIO in patients undergoing major liver resection.

METHODS

Assessment of hepatic microcirculation was performed using a handheld vital microscope (HVM) at the beginning of surgery, end of VIO (20 minutes) and during reperfusion after the termination of VIO. The microcirculatory parameters assessed were: functional capillary density (FCD), microvascular flow index (MFI) and sinusoidal diameter (SinD).

RESULTS

A total of 15 patients underwent VIO; 8 patients showed hepatic microvascular perfusion despite VIO (partial responders) and 7 patients showed complete cessation of hepatic microvascular perfusion (full responders). Functional microvascular parameters and blood flow levels were significantly higher in the partial responders when compared to the full responders during VIO (FCD: 0.84±0.88 vs. 0.00±0.00 mm/mm2, P<0.03, respectively, and MFI: 0.69-0.22 vs. 0.00±0.00, P<0.01, respectively).

CONCLUSIONS

An interpatient heterogeneous response in hepatic microvascular blood flow was observed upon VIO. This may explain why clinical strategies to protect the liver against IRI lacked consistency.

Biomarkers of Liver Injury during Transplantation in an Era of Machine Perfusion

Liver ischaemia–reperfusion injury (IRI) is an intrinsic part of the transplantation process and damages the parenchymal cells of the liver including hepatocytes, endothelial cells and cholangiocytes. Many biomarkers of IRI have been described over the past two decades that have attempted to quantify the extent of IRI involving different hepatic cellular compartments, with the aim to allow clinicians to predict the suitability of donor livers for transplantation. The advent of machine perfusion has added an additional layer of complexity to this field and has forced researchers to re-evaluate the utility of IRI biomarkers in different machine preservation techniques. In this review, we summarise the current understanding of liver IRI biomarkers and discuss them in the context of machine perfusion.

Analysis of Data from the Oxygen Persufflation in Liver Transplantation (OPAL) Study to Determine the Role of Factors Affecting the Hepatic Microcirculation and Early Allograft Dysfunction

Background

Adequate microcirculatory perfusion is essential for the provision of oxygen to the liver following transplantation. Data from the Oxygen Persufflation in Liver Transplantation (OPAL) study (ISRCTN00167887) were analyzed from liver transplants performed at a single center to determine the role of factors affecting the hepatic microcirculation and early allograft dysfunction (EAD).

Material/Methods

Retrospective data from 116 patients from the Oxygen Persufflation as Adjunction in Liver Transplantation (OPAL) study who underwent liver transplantation at a single center were analyzed. Oxygen saturation of hemoglobin (SO₂), relative capillary hemoglobin concentration (rHb), relative tissue blood flow (rBF) using laser Doppler flow measurements, and the Oxygen-to-See (O2C) spectrometry were measured and with post-transplant allograft function were analyzed using univariate and multivariate logistic regression statistics.

Results

Livers donors had a median donor risk index of 1.8. Most liver transplant recipients were men (60.3%), with a median age of 54 years (IQR, 23–68 years). Mean post-transplant 3-month survival was 90.5%. The EAD rate was 22.4%, the median SO₂ was 78% (IQR, 29.5–95.8%), the median rHb was 55.6 AU (IQR, 16.8–74.8 AU), and the median rBF was 110.1 AU (IQR, 35.8–406.8 AU). Multivariate logistic regression analysis showed that tissue SO₂ (p=0.01), body mass index (BMI) of the transplant recipient (p=0.002), serum alanine transaminase (ALT) of the donor (p=0.02), and portal blood flow (p=0.01) were predictive factors for EAD.

Conclusions

Non-invasive investigations of the liver microcirculation and hemoglobin oxygenation were shown to be predictive factors for EAD following liver transplantation.

Platelets and Platelet-Derived Extracellular Vesicles in Liver Physiology and Disease

Beyond their role in hemostasis, platelets are proposed as key mediators of several physiological and pathophysiological processes of the liver, such as liver regeneration, toxic or viral acute liver injury, liver fibrosis, and carcinogenesis. The effects of platelets on the liver involve interactions with sinusoidal endothelial cells and the release of platelet‐contained molecules following platelet activation. Platelets are the major source of circulating extracellular vesicles, which are suggested to play key roles in platelet interactions with endothelial cells in several clinical disorders. In the present review, we discuss the implications of platelet‐derived extracellular vesicles in physiological and pathophysiological processes of the liver.

The Macrophage Activation Marker Soluble CD163 is Associated With Early Allograft Dysfunction After Liver Transplantation

BACKGROUND/OBJECTIVES

Soluble CD163 (sCD163), a macrophage activation marker, is upregulated in conditions of macrophage proliferation and activation. Elevated sCD163 levels have been associated with liver disease severity and progression. During liver transplantation, the implanted liver is exposed to ischaemia and reperfusion injury, resulting in an acute inflammatory response and macrophage activation. The relationship between sCD163 levels during liver transplantation and the development of early allograft dysfunction (EAD) has not been investigated.

METHODS

We included 27 cirrhosis patients (age 55 [range 32-72] years, 23 men) on the waiting list for liver transplantation. Alcohol consumption and viral hepatitis were the most frequent causes for cirrhosis. Patients were characterised by standard biochemical analysis and based on clinical disease severity scores. Information about donor, graft and course of the liver transplantation was recorded. sCD163 levels were measured at the time of liver transplantation before surgery, 2 h after reperfusion, and then at 24 h after transplantation.

RESULTS

We observed above-normal sCD163 levels at baseline (5.9 mg/L [4.7-8.8]). Two hours after reperfusion, sCD163 levels increased significantly from baseline (8.4 mg/L [7.4-10.9]; P < 0.01). Twenty-four hours after transplantation, sCD163 levels were significantly reduced compared with baseline (3.7 mg/L [2.9-5.5]; P < 0.01). However, in patients with EAD (n = 16), sCD163 levels were increased compared with patients without EAD (4.1 [3.2-7.4] vs. 3.1 [2.8-3.8] mg/L; P = 0.03).

CONCLUSIONS

We observed elevated sCD163 levels in patients with EAD after liver transplantation, confirming macrophage activation to play a role in EAD. Thus, sCD163 may be used as an early marker for EAD after liver transplantation, but larger studies are warranted to validate these findings.

Molecular profiling of postreperfusion milieu determines acute kidney injury after liver transplantation: A prospective study

Acute kidney injury (AKI) after liver transplantation (LT) is a common event, but its pathogenesis remains unclear. The aim of this prospective study is to investigate the potential relationship between postreperfusion gene expression, serum mediators, and the onset of AKI after LT. Sixty-five consecutive patients undergoing LT were included in the study. Reverse transcription polymerase chain reaction (PCR) was performed on liver biopsies. Gene expression of 23 genes involved in ischemia/reperfusion injury (IRI) was evaluated. The serum concentrations of endothelin (ET)-1 and inflammatory cytokines were analyzed. AKI after LT developed in 21 (32%) recipients (AKI group). Reverse transcription PCR of reperfusion biopsy in the AKI group showed higher expression of several genes involved in IRI compared with the non-AKI group. Fold changes in the gene expression of ET-1, interleukin (IL) 18, and tumor necrosis factor α (TNF-α) were associated with creatinine peak value. AKI patients also had significantly higher ET-1, IL18, and TNF-α postoperative serum levels. Multivariate analysis showed that ET-1 (odds ratio [OR], 16.7; 95% confidence interval [CI], 3.34-83.42; P = 0.001) and IL18 (OR, 5.27; 95% CI, 0.99-27.82, P = 0.048) serum levels on postoperative day 1 were independently predictive of AKI. Receiver operating characteristic analysis demonstrated that the combination of biomarkers ET-1+IL18 was highly predictive of AKI (area under the receiver operating characteristic curve, 0.91; 95% CI, 0.83-0.99). Early allograft dysfunction and chronic kidney disease stage ≥ 2 occurred more frequently in AKI patients. These results suggest that the graft itself, rather than intraoperative hemodynamic instability, plays a main role in AKI after LT. These data may have mechanistic and diagnostic implications for AKI after LT. Liver Transplantation 24 922-931 2018 AASLD.