Serum Factor V Is a Continuous Biomarker of Graft Dysfunction and a Predictor of Graft Loss After Liver Transplantation

Value of Factor V in the diagnosis of early graft dysfunction after liver transplantation: Internal validation

Primary graft dysfunction is a major early complication following liver transplantation, potentially leading to retransplantation or patient death. Coagulation Factor V (FV) and ALT have emerged as important biomarkers in assessing liver function, yet their role as early predictors of graft loss has not been fully validated. The aim of this study is to conduct an internal validation of published results on the applicability of FV and ALT for diagnosing graft dysfunction and its predictive ability for graft loss within the first 90 days. We conducted a retrospective cohort study including 513 adult recipients from 2012 to 2023 at the Regional University Hospital of Málaga. FV and ALT levels were measured on postoperative day 2, and patients were categorized based on FV <37.5 and ALT >1539. The association with 90-day graft loss was analyzed. Graft loss occurred in 43 patients (8.4%) within the first 90 days. The combination of FV <37.5 and ALT >1539 on postoperative day 2 demonstrated a specificity of 99% and a test efficiency of 94% in predicting graft loss. Patients meeting both criteria had a 74-fold increased risk of graft loss, with most losses occurring within the first week, and a median survival of 4 days. These findings suggest that FV and ALT on postoperative day 2 are reliable early markers for predicting graft loss, enabling risk stratification and guiding critical decisions regarding early retransplantation in the immediate postoperative period.

Factor V Serves as an Early Biomarker for Graft Loss After Liver Transplant: A Prospective Evaluation

BACKGROUND

Low post-operative day (POD) 1 Factor V has been retrospectively associated with graft loss after liver transplantation when stratified by a cutoff of 0.36 U/mL. We aimed to validate this prospectively.

METHODS

Patients transplanted at Toronto General Hospital were recruited (May 2018-March 2021). Factor V measurements were obtained on POD1-3, 5, and 7. Graft and patient survival at 3, 6, and 12 months were primary and secondary outcomes, respectively. We identified an optimal cutoff through receiver operating characteristic (ROC) analysis and the Youden index. Kaplan-Meier method and Log-rank tests were used to assess/compare survival.

RESULTS

One hundred and twenty-nine patients were included. One hundred and eight had Factor V >0.36 and 21 had ≤0.36 U/mL. This cutoff was predictive of 6- and 12-month graft survival and 12-month patient survival. With an optimal cutoff of 0.46 U/mL on POD1, 87 patients had Factor V >0.46 and 42 had ≤0.46 U/mL. Three-, 6-, and 12-month graft survival rates were 100%, 98.8%, and 98.8%, for patients with Factor V >0.46 U/mL, and 92.9%, 87.7%, and 87.7% for Factor V ≤0.46 U/mL. Similarly, 3-, 6-, and 12-month patient survival rates were 98.8%, 96.4%, and 95.0% for patients with Factor V >0.46 U/mL, and 92.9%, 88.0%, and 82.9% for Factor V ≤0.46 U/mL. Stratification below the novel cutoff was associated with decreased graft survival at months 3 (p = 0.012), 6 (p = 0.006), and 12 (p = 0.006), and decreased patient survival at 12 months (p = 0.022).

CONCLUSIONS

Factor V serves as an early biomarker for graft loss, with an optimal predictive cutoff of 0.46 U/mL in this prospective population. Validation of this new cutoff is necessary.

Advancements in Predictive Tools for Primary Graft Dysfunction in Liver Transplantation: A Comprehensive Review

Orthotopic liver transplantation stands as the sole curative solution for end-stage liver disease. Nevertheless, the discrepancy between the demand and supply of grafts in transplant medicine greatly limits the success of this treatment. The increasing global shortage of organs necessitates the utilization of extended criteria donors (ECD) for liver transplantation, thereby increasing the risk of primary graft dysfunction (PGD). Primary graft dysfunction (PGD) encompasses early allograft dysfunction (EAD) and the more severe primary nonfunction (PNF), both of which stem from ischemia-reperfusion injury (IRI) and mitochondrial damage. Currently, the only effective treatment for PNF is secondary transplantation within the initial post-transplant week, and the occurrence of EAD suggests an elevated, albeit still uncertain, likelihood of retransplantation urgency. Nonetheless, the ongoing exploration of novel IRI mitigation strategies offers hope for future improvements in PGD outcomes. Establishing an intuitive and reliable tool to predict upcoming graft dysfunction is vital for early identification of high-risk patients and for making informed retransplantation decisions. Accurate diagnostics for PNF and EAD constitute essential initial steps in implementing future mitigation strategies. Recently, novel methods for PNF prediction have been developed, and several models for EAD assessments have been introduced. Here, we provide an overview of the currently scrutinized predictive tools for PNF and EAD evaluation strategies, accompanied by recommendations for future studies.

Complications in Post-Liver Transplant Patients

Liver transplantation (LT) is the treatment of choice for liver failure and selected cases of malignancies. Transplantation activity has increased over the years, and indications for LT have been widened, leading to organ shortage. To face this condition, a high selection of recipients with prioritizing systems and an enlargement of the donor pool were necessary. Several authors published their case series reporting the results obtained with the use of marginal donors, which seem to have progressively improved over the years. The introduction of in situ and ex situ machine perfusion, although still strongly debated, and better knowledge and treatment of the complications may have a role in achieving better results. With longer survival rates, a significant number of patients will suffer from long-term complications. An extensive review of the literature concerning short- and long-term outcomes is reported trying to highlight the most recent findings. The heterogeneity of the behaviors within the different centers is evident, leading to a difficult comparison of the results and making explicit the need to obtain more consent from experts.

Biomarkers and predictive models of early allograft dysfunction in liver transplantation - A systematic review of the literature, meta-analysis, and expert panel recommendations

BACKGROUND

Prompt identification of early allograft dysfunction (EAD) is critical to reduce morbidity and mortality in liver transplant (LT) recipients.

OBJECTIVES

Evaluate the evidence supporting biomarkers that can provide diagnostic and predictive value for EAD.

DATA SOURCES

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

METHODS

Systematic review following PRISMA guidelines and recommendations using the GRADE approach was derived from an international expert panel. Studies that investigated biomarkers or models for predicting EAD in adult LT recipients were included for in-depth evaluation and meta-analysis. Olthoff's criteria were used as the standard reference for the diagnostic accuracy evaluation.

PROSPERO ID

CRD42021293838 RESULTS: Ten studies were included for the systematic review. Lactate, lactate clearance, uric acid, Factor V, HMGB-1, CRP to ALB ratio, phosphocholine, total cholesterol, and metabolomic predictive model were identified as potential early EAD predictive biomarkers. The sensitivity ranged between .39 and .92, while the specificity ranged from .63 to .90. Elevated lactate level was most indicative of EAD after adult LT (pooled diagnostic odds ratio of 7.15 (95%CI: 2.38-21.46)). The quality of evidence (QOE) for lactate as indicator was moderate according to the GRADE approach, whereas the QOE for other biomarkers was very low to low likely as consequence of study design characteristics such as single study, small sample size, and large ranges of sensitivity or specificity.

CONCLUSIONS

Lactate is an early indicator to predict EAD after LT (Quality of Evidence: Moderate | Grade of Recommendation: Strong). Further multicenter studies and the use of machine perfusion setting should be implemented for validation.

Combination of Early Allograft Dysfunction and Protein Expression Patterns Predicts Outcome of Liver Transplantation From Donation After Cardiac Death

Early allograft dysfunction (EAD) after liver transplantation (LT) accompanies poor prognosis. This study aims to explore the relationship between pretransplant intrahepatic proteins and the incidence of EAD, and the value of combined EAD and protein profiles for predicting recipient and graft survival prognosis. Liver biopsy specimens of 105 pretransplant grafts used for LT were collected and used for immunohistochemistry analysis of 5 proteins. And matched clinical data of donor, recipient, transplantation, and prognosis were analyzed. The incidence of EAD was 41.9% (44/105) in this cohort. Macrovesicular steatosis (P = 0.016), donor body mass index (P = 0.013), recipients' pretransplant serum creatinine (P = 0.036), and intrahepatic expression of heme oxygenase 1 (HO1) (P = 0.015) and tumor necrosis factor α (TNF-α) (P = 0.039) were independent predictors of EAD. Inferior graft and recipient prognosis were observed in patients who experienced EAD (P = 0.028 and 0.031) or received grafts with higher expression of sirtuin 1 (P = 0.005 and 0.013). The graft and recipient survival were worst in patients with both EAD and high expression of sirtuin 1 (P = 0.001 and 0.004). In conclusion, pretransplant intrahepatic expression of HO1 and TNF-α are associated with the incidence of EAD. The combination of EAD and EAD-unrelated proteins showed superiority in distinguishing recipients with worse prognosis.

Short series regarding uncontrolled donor after cardiac death: A call for caution

The authors did not receive any funding for this work.

Combination of arterial lactate levels and Cv-aCO2/Da-vO2 ratio to predict early allograft dysfunction after liver transplantation

PURPOSE

We examined the ability of the P(v-a)CO2/Da-vO2 ratio combined with elevated lactate levels to predict early allograft dysfunction (EAD).

MATERIALS AND METHODS

Patients were classified into four groups according to lactate levels and P(v-a)CO2/Da-vO2 ratio: Group 1; lactate >2.0 mmol/L and P(v-a)CO2/Da-vO2 ratio >1.0; Group 2; lactate >2.0 mmol/L and P(v-a)CO2/Da-vO2 ratio <1.0; group 3; lactate<2.0 mmol/L and P(v-a)CO2/Da-vO2 ratio >1.0; group 4; lactate<2.0 mmol/L and P(v-a)CO2/Da-vO2 ratio <1.0. We defined EAD according to Olthoff criteria.

RESULTS

One-hundred and fifty patients were included. EAD occurred in 41 patients (27.3%), and was associated with worse graft survival at 1 year (92% vs. 73%; P = ,003) as well as a higher re-transplantation rate (4,6% vs. 17,1%; P = ,019). The multivariate analysis revealed that P(v-a)CO2/Da-vO2 ratio at T6 [OR 7.05(CI95% 2.77-19.01, P<.001)] was an independent predictor for EAD. Belonging to group 1 at 6 h was associated with worse clinical outcomes but no association was found with 1-year graft survival or 1-year patient survival.

CONCLUSIONS

In this single center, prospective, observational study in patients who received an OLT, we found that elevated lactate levels combined with a high Cv-aCO2/Da-vO2 after 6 h was associated with the development of EAD and worse clinical outcomes in the early postoperative period.

Synthesis of coagulation factors during long-term ex situ liver perfusion

Robust viability assessment of grafts during normothermic liver perfusion is a prerequisite for organ use. Coagulation parameters are used commonly for liver assessment in patients. However, they are not yet included in viability assessment during ex situ perfusion. In this study, we analysed coagulation parameters during one week ex situ perfusion at 34℃. Eight discarded human livers were perfused with blood-based, heparinised perfusate for one week; perfusions in a further four livers were terminated on day 4 due to massive ongoing cell death. Coagulation parameters were well below the physiologic range at perfusion start. Physiologic levels were achieved within the first two perfusion days for factor V (68.5 ± 35.5%), factor VII (83.5 ± 26.2%), fibrinogen (2.1 ± 0.4 g/L) and antithrombin (107 ± 26.5%) in the livers perfused for one week. Despite the increased production of coagulation factors, INR was detectable only at 24h of perfusion (2.1 ± 0.3) and prolonged thereafter (INR > 9). The prolongation of INR was related to the high heparin level in the perfusate (anti-FXa > 3 U/mL). Intriguingly, livers with ongoing massive cell death also disclosed synthesis of factor V and improved INR. In summary, perfused livers were able to produce coagulation factors at a physiological level ex situ. We propose that single coagulation factor analysis is more reliable for assessing the synthetic function of perfused livers as compared to INR when using a heparinised perfusate.

Design, Analysis, and Pitfalls of Clinical Trials Using Ex Situ Liver Machine Perfusion: The International Liver Transplantation Society Consensus Guidelines

BACKGROUND

Recent trials in liver machine perfusion (MP) have revealed unique challenges beyond those seen in most clinical studies. Correct trial design and interpretation of data are essential to avoid drawing conclusions that may compromise patient safety and increase costs.

METHODS

The International Liver Transplantation Society, through the Special Interest Group "DCD, Preservation and Machine Perfusion," established a working group to write consensus statements and guidelines on how future clinical trials in liver perfusion should be designed, with particular focus on relevant clinical endpoints and how different techniques of liver perfusion should be compared. Protocols, abstracts, and full published papers of clinical trials using liver MP were reviewed. The use of a simplified Grading of Recommendations Assessment, Development, and Evaluation working group (GRADE) system was attempted to assess the level of evidence. The working group presented its conclusions at the International Liver Transplantation Society consensus conference "DCD, Liver Preservation, and Machine Perfusion" held in Venice, Italy, on January 31, 2020.

RESULTS

Twelve recommendations were proposed with the main conclusions that clinical trials investigating the effect of MP in liver transplantation should (1) make the protocol publicly available before the start of the trial, (2) be adequately powered, and (3) carefully consider timing of randomization in function of the primary outcome.

CONCLUSIONS

There are issues with using accepted primary outcomes of liver transplantation trials in the context of MP trials, and no ideal endpoint could be defined by the working group. The setup of an international registry was considered vital by the working group.

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.

Peritransplant kinetics of Mac-2-binding protein glycosylation isomer levels in living donor liver transplantation: its implication of posttransplant small-for-size syndrome

Background

Wisteria floribunda agglutinin positive human Mac-2 binding protein glycosylation isomer (M2BPGi) has recently developed as a noninvasive serum marker of liver fibrosis. Liver transplant candidates usually have high serum levels of M2BPGi due to advanced cirrhosis. The aim of the present study was to elucidate the kinetics of serum M2BPGi after liver transplantation and the relationships between the level of M2BPGi and graft function.

Methods

Fifteen recipients who underwent living donor liver transplantation (LDLT) between June 2015 and January 2016 and whose pretransplant, postoperative day (POD) 1, POD 3, and POD 7 sera were available for measuring M2BPGi were enrolled in this study. Small-for-size syndrome (SFSS) was defined as the presence of cholestasis (total bilirubin >10 mg/dL) on POD 7 and intractable ascites (>1 L/day on POD 14 or >500 ml/day on POD 28) without other specific causes.

Results

The median of pretransplant M2BPGi was 9.75 cutoff index (C.O.I.) (range, 3.04-24.49). There was neither any correlation between pretransplant M2BPGi and Model for End-Stage Liver Disease scores (r=0.416, P=0.123) nor Child-Turcotte-Pugh scores (r=-0.221, P=0.428). The levels of M2BPGi dramatically decreased after LDLT (median; 1.48 on POD 1, 1.47 on POD 3, 1.49 on POD 7). However, serum levels of M2BPGi rose again on POD 7 in some recipients and all 4 recipients with serum levels of M2BPGi exceeding 3.00 C.O.I. succumbed to SFSS later. When the cutoff of M2BPGi on POD 7 for predicting SFSS was determined to be 3.06 according to its receiver operating characteristic curve, both the sensitivity and the specificity for predicting later SFSS were 100%.

Conclusions

The levels of M2BPGi dramatically decreased after LDLT. A re-rise of M2BPGi predicted later development of SFSS.