Coagulation management during liver transplantation: monitoring and decision making for hemostatic interventions

PURPOSE OF REVIEW

Rebalanced hemostasis describes the precarious balance of procoagulant and antithrombotic proteins in patients with severe liver failure. This review is aimed to discuss currently available coagulation monitoring tests and pertinent decision-making process for plasma coagulation factor replacements during liver transplantation (LT).

RECENT FINDINGS

Contemporary viscoelastic coagulation monitoring systems have demonstrated advantages over conventional coagulation tests in assessing the patient's coagulation status and tailoring hemostatic interventions. There is increasing interest in the use of prothrombin complex and fibrinogen concentrates, but it remains to be proven if purified factor concentrates are more efficacious and safer than allogeneic hemostatic components. Furthermore, the decision to use antifibrinolytic therapy necessitates careful considerations given the risks of venous thromboembolism in severe liver failure.

SUMMARY

Perioperative hemostatic management and thromboprophylaxis for LT patients is likely to be more precise and patient-specific through a better understanding and monitoring of rebalanced coagulation. Further research is needed to refine the application of these tools and develop more standardized protocols for coagulation management in LT.

Management of severe peri-operative bleeding: Guidelines from the European Society of Anaesthesiology and Intensive Care: Second update 2022

BACKGROUND

Management of peri-operative bleeding is complex and involves multiple assessment tools and strategies to ensure optimal patient care with the goal of reducing morbidity and mortality. These updated guidelines from the European Society of Anaesthesiology and Intensive Care (ESAIC) aim to provide an evidence-based set of recommendations for healthcare professionals to help ensure improved clinical management.

DESIGN

A systematic literature search from 2015 to 2021 of several electronic databases was performed without language restrictions. Grading of Recommendations, Assessment, Development and Evaluation (GRADE) was used to assess the methodological quality of the included studies and to formulate recommendations. A Delphi methodology was used to prepare a clinical practice guideline.

RESULTS

These searches identified 137 999 articles. All articles were assessed, and the existing 2017 guidelines were revised to incorporate new evidence. Sixteen recommendations derived from the systematic literature search, and four clinical guidances retained from previous ESAIC guidelines were formulated. Using the Delphi process on 253 sentences of guidance, strong consensus (>90% agreement) was achieved in 97% and consensus (75 to 90% agreement) in 3%.

DISCUSSION

Peri-operative bleeding management encompasses the patient's journey from the pre-operative state through the postoperative period. Along this journey, many features of the patient's pre-operative coagulation status, underlying comorbidities, general health and the procedures that they are undergoing need to be taken into account. Due to the many important aspects in peri-operative nontrauma bleeding management, guidance as to how best approach and treat each individual patient are key. Understanding which therapeutic approaches are most valuable at each timepoint can only enhance patient care, ensuring the best outcomes by reducing blood loss and, therefore, overall morbidity and mortality.

CONCLUSION

All healthcare professionals involved in the management of patients at risk for surgical bleeding should be aware of the current therapeutic options and approaches that are available to them. These guidelines aim to provide specific guidance for bleeding management in a variety of clinical situations.

Pain management in patients with hepatocellular carcinoma after transcatheter arterial chemoembolisation: A retrospective study

BACKGROUND

Pain after transcatheter arterial chemoembolisation (TACE) can seriously affect the prognosis of patients and the insertion of additional medical resources.

AIM

To develop an early warning model for predicting pain after TACE to enable the implementation of preventive analgesic measures.

METHODS

We retrospectively collected the clinical data of 857 patients (from January 2016 to January 2020) and prospectively enrolled 368 patients (from February 2020 to October 2022; as verification cohort) with hepatocellular carcinoma (HCC) who received TACE in the Hepatic Surgery Center of Tongji Hospital. Five predictive models were established using machine learning algorithms, namely, random forest model (RFM), support vector machine model, artificial neural network model, naive Bayes model and decision tree model. The efficacy of these models in predicting postoperative pain was evaluated through receiver operating characteristic curve analysis, decision curve analysis and clinical impact curve analysis.

RESULTS

A total of 24 candidate variables were included in the predictive models using the iterative algorithms. Age, preoperative pain, number of embolised tumours, distance from the liver capsule, dosage of iodised oil and preoperative prothrombin activity were closely associated with postoperative pain. The accuracy of the predictive model was compared between the training [area under the curve (AUC) = 0.798; 95% confidence interval (CI): 0.745-0.851] and verification (AUC = 0.871; 95%CI: 0.818-0.924) cohorts, with RFM having the best predictive efficiency (training cohort: AUC = 0.869, 95%CI: 0.816-0.922; internal verification cohort: AUC = 0.871; 95%CI: 0.818-0.924).

CONCLUSION

The five predictive models based on advanced machine learning algorithms, especially RFM, can accurately predict the risk of pain after TACE in patients with HCC. RFM can be used to assess the risk of pain for facilitating preventive treatment and improving the prognosis.

Preoperative Fibrinogen Level and Bleeding in Liver Transplantation for End-stage Liver Disease: A Cohort Study

BACKGROUND

Liver transplantation is a high-risk surgery associated with important perioperative bleeding and transfusion needs. Uncertainties remain on the association between preoperative fibrinogen level and bleeding in this population.

METHODS

We conducted a cohort study that included all consecutive adult patients undergoing a liver transplantation for end-stage liver disease in 1 center. We analyzed the association between the preoperative fibrinogen level and bleeding-related outcomes. Our primary outcome was intraoperative blood loss, and our secondary outcomes were estimated perioperative blood loss, intraoperative and perioperative red blood cell transfusions, reinterventions for bleeding and 1-y graft and patient survival. We estimated linear regression models and marginal risk models adjusted for all important potential confounders. We used restricted cubic splines to explore potential nonlinear associations and reported dose-response curves.

RESULTS

We included 613 patients. We observed that a lower fibrinogen level was associated with a higher intraoperative blood loss, a higher estimated perioperative blood loss and a higher risk of intraoperative and perioperative red blood cell transfusions (nonlinear effects). Based on an exploratory analysis of the dose-response curves, these effects were observed below a threshold value of 3 g/L for these outcomes. We did not observe any association between preoperative fibrinogen level and reinterventions, 1-y graft survival or 1-y patient survival.

CONCLUSIONS

This study suggests that a lower fibrinogen level is associated with bleeding in liver transplantation. The present results may help improving the selection of patients for further studies on preoperative fibrinogen administration in liver transplant recipients with end-stage liver disease.

The Pharmacokinetics and Pharmacodynamics of A Novel Recombinant Activated Human Factor VII, GEN-0828, in Hemophilia B Mice

GEN-0828, a proposed clinical candidate for hemophilia and trauma hemorrhage treatment, is a novel recombinant activated human factor VII (rFVIIa). The purpose of this paper is to compare the pharmacokinetics and pharmacodynamics of GEN-0828 in hemophilia B mice with those of NovoSeven®, the only marketed rFVIIa product worldwide., GEN-0828 and NovoSeven® showed similar affinity bioactivity to recombinant tissue factor (rTF) in vitro. Pharmacodynamics data indicated a generally similar hemostatic efficacy (ED₅₀) of GEN-0828 (10.91 KIU·kg^-1) and NovoSeven® (18.91 KIU·kg^-1) at the doses studied in hemophilia B mice, while GEN-0828 represented a lower initial effective dosage compared with that of NovoSeven® in terms of both blood loss and APTT. GEN-0828 exhibited linear pharmacokinetic profiles in hemophilia B mice at the 30-338 KIU·kg^-1 dose range, the comparative pharmacokinetic study with NovoSeven® indicated better characteristics than NovoSeven® in terms of the appropriate higher maximal concentration (C_max) and area under the plasma concentration-time curve (AUC_last) and longer mean residence time (MRT). In conclusion, GEN-0828 was a promising new type of rFVIIa compound with favourable pharmacokinetic and pharmacodynamic profiles.

Blood utilization in liver transplantation (BUILT): A multidisciplinary survey of transfusion practices

BACKGROUND

The purpose of this study was to survey liver transplant centers in the United States to assess baseline practices in blood utilization and identify opportunities for standardization to optimize blood use in these complex cases.

STUDY DESIGN AND METHODS

Two surveys, one for transfusion medicine physicians and the other for anesthesiologists, were distributed to high-volume liver transplant centers.

RESULTS

The response rate was 52% for both surveys. The majority of respondents (90%) indicated they issue a standardized number of blood products to start surgeries. The most common number of products issued before the start of cases were 10 red blood cells (RBC) and 10 plasma units with no platelets or cryoprecipitate. On average, fewer RBC (7.5) and plasma (7) units were transfused than issued. Decisions to transfuse RhD+ RBCs to RhD- patients and use antigen untested units in alloimmunized patients were mainly handled on a case-by-case basis. Many centers reported utilizing viscoelastic testing (97%) and cell salvage (97%). Most centers reported standardized, laboratory-based intraoperative transfusion goals for RBCs (65%) and fibrinogen replacement (52%) but lacked a standardized approach for plasma (55%) and platelets (58%).

DISCUSSION

More blood products are issued during surgery than are transfused. Responses from anesthesiology providers suggest a broad consensus on practice. Almost all respondents use viscoelastic testing in the management of intraoperative coagulopathy, either alone or in combination with classical coagulation tests. The majority of programs do not transfuse clotting factor concentrates, including fibrinogen concentrate, prothrombin complex concentrates, and recombinant activated FVII, and do not use antifibrinolytics prophylactically.

Individualized Management of Coagulopathy in Patients with End-Stage Liver Disease

Over the last decades, individualized approaches and a better understanding of coagulopathy complexity in end-stage liver disease (ESLD) patients has evolved. The risk of both thrombosis and bleeding during minimally invasive interventions or surgery is associated with a worse outcome in this patient population. Despite deranged quantitative and qualitative coagulation laboratory parameters, prophylactic coagulation management is unnecessary for patients who do not bleed. Transfusion of red blood cells (RBCs) and blood products carries independent risks for morbidity and mortality, including modulation of the immune system with increased risk for nosocomial infections. Optimal coagulation management in these complex patients should be based on the analysis of standard coagulation tests (SCTs) and viscoelastic tests (VETs). VETs represent an individualized approach to patients and can provide information about coagulation dynamics in a concise period of time. This narrative review will deliver the pathophysiology of deranged hemostasis in ESLD, explore the difficulties of evaluating the coagulopathies in liver disease patients, and examine the use of VET assays and management of coagulopathy using coagulation factors. Methods: A selective literature search with PubMed as the central database was performed with the following.

Perioperative prothrombin complex concentrate and fibrinogen administration are associated with thrombotic complications after liver transplant

BACKGROUND

Use of intraoperative prothrombin complex concentrates (PCC) and fibrinogen concentrate administration has been linked to thrombotic events. However, it is unknown if its use is associated with thrombotic events after liver transplant.

METHODS AND ANALYSIS

We conducted a post hoc analysis of a prospectively conducted registry database study on patients who underwent liver transplant between 2004 and 2017 at Heidelberg University Hospital, Heidelberg, Germany. Univariate and multivariate analyses were used to determine the association between PCC and fibrinogen concentrate administration and thrombotic complications.

RESULTS

Data from 939 transplantations were included in the analysis. Perioperative PCC or fibrinogen administration was independently associated with the primary composite endpoint Hepatic artery thrombosis (HAT), Portal vein thrombosis (PVT), and inferior vena cava thrombosis [adjusted HR: 2.018 (1.174; 3.468), p = 0.011]. PCC or fibrinogen administration was associated with the secondary endpoints 30-day mortality (OR 4.225, p < 0.001), graft failure (OR 3.093, p < 0.001), intraoperative blood loss, red blood cell concentrate, fresh frozen plasma and platelet transfusion, longer hospitalization, and longer length of stay in intensive care units (ICUs) (all p < 0.001). PCC or fibrinogen administration were not associated with pulmonary embolism, myocardial infarction, stroke, or deep vein thrombosis within 30 days after surgery.

CONCLUSION

A critical review of established strategies in coagulation management during liver transplantation is warranted. Perioperative caregivers should exercise caution when administering coagulation factor concentrate during liver transplant surgery. Prospective randomized controlled trials are needed to establish causality for the relationship between coagulation factors and thrombotic events in liver transplantation. Further studies should be tailored to identify patient subgroups that will likely benefit from PCC or fibrinogen administration.

Controlled DCD Liver Transplantation Is Not Associated With Increased Hyperfibrinolysis and Blood Loss After Graft Reperfusion

BACKGROUND

The specific effect of donation after circulatory death (DCD) liver grafts on fibrinolysis, blood loss, and transfusion requirements after graft reperfusion is not well known. The aim of this study was to determine whether transplantation of controlled DCD livers is associated with an elevated risk of hyperfibrinolysis, increased blood loss, and higher transfusion requirements upon graft reperfusion, compared with livers donated after brain death (DBD).

METHODS

A retrospective single-center analysis of all adult recipients of primary liver transplantation between 2000 and 2019 was performed (total cohort n = 628). Propensity score matching was used to balance baseline characteristics for DCD and DBD liver recipients (propensity score matching cohort n = 218). Intraoperative and postoperative hemostatic variables between DCD and DBD liver recipients were subsequently compared. Additionally, in vitro plasma analyses were performed to compare the intraoperative fibrinolytic state upon reperfusion.

RESULTS

No significant differences in median (interquartile range) postreperfusion blood loss (1.2 L [0.5-2.2] versus 1.3 L [0.6-2.2]; P = 0.62), red blood cell transfusion (2 units [0-4] versus 1.1 units [0-3]; P = 0.21), or fresh frozen plasma transfusion requirements (0 unit [0-2.2] versus 0 unit [0-0.9]; P = 0.11) were seen in DCD compared with DBD recipients, respectively. Furthermore, plasma fibrinolytic potential was similar in both groups.

CONCLUSIONS

Transplantation of controlled DCD liver grafts does not result in higher intraoperative blood loss or more transfusion requirements, compared with DBD liver transplantation. In accordance with this, no evidence for increased hyperfibrinolysis upon reperfusion in DCD compared with DBD liver grafts was found.

Disseminated intravascular coagulation following air embolism during orthotropic liver transplantation: is this just a coincidence?

BACKGROUND

During orthotopic liver transplantation, venous air embolism may occur due to iatrogenic injury of the inferior vena cava. However, venous air embolism followed by coagulopathy is a rare event. In this case report, we discuss a possible connection between venous air embolism and disseminated intravascular coagulation.

CASE PRESENTATION

A 37-year-old male patient with chronic hepatitis B- and C-induced liver cirrhosis was admitted for orthotopic liver transplantation. During the dissection phase of the surgery, arterial blood pressure, heart rate, saturation and end-tidal carbon dioxide levels suddenly decreased, indicating the occurrence of venous air embolism. After stabilizing the patient's condition, various coagulation issues started developing. Venous air embolism-induced coagulopathy was handled by administering transfusions of various blood products. However, the patient's condition continued to deteriorate leading to a complete asystole.

CONCLUSIONS

This is a rare case of venous air embolism-induced disseminated intravascular coagulation. The real connection remains unclear as disseminated intravascular coagulation for end-stage liver disease patients can be induced by various causes during different stages of liver transplantation. Certainly, both venous air embolism and coagulopathy were significant and led to an unfavorable outcome. Further studies are needed to better understand the possible mechanisms and correlation between these two life-threatening complications.

Roles of Four-Factor Prothrombin Complex Concentrate in the Management of Critical Bleeding

Four-factor prothrombin complex concentrate (4F-PCC) is the term used to describe a pathogen-reduced, lyophilized concentrate that contains therapeutic amounts of at least 4 coagulation factors: Factor II (FII), Factor VII (FVII), Factor IX (FIX), and Factor X (FX). 4F-PCC has proven to be an effective hemostatic agent compared to plasma transfusion in several prospective randomized trials in acute warfarin reversal. In recent years, 4F-PCC has been used in various acquired coagulopathies including post-cardiopulmonary bypass bleeding, trauma-induced coagulopathy, coagulopathy in liver failure, and major bleeding due to anti-FXa (anti-Xa) inhibitors (eg, rivaroxaban and apixaban). As transfusion of frozen plasma (FP) has not been found efficacious in the above critical bleeding scenarios, there is increasing interest in expanding the use of 4F-PCC. However, efficacy, safety, and clinical implications of expanded use of 4F-PCC have not been fully elucidated. Prothrombin time and international normalized ratio are commonly used to assess dose effects of 4F-PCC. Prothrombin time/international normalized ratio are standardly use for warfarin titration, but they are not suited for real-time monitoring of complex coagulopathies. Optimal dosing of 4F-PCC outside of the current approved use for vitamin K antagonist reversal is yet to be determined. In this review, we will discuss the use of 4F-PCC in four critical bleeding settings: cardiac surgery, major trauma, end-stage liver disease, and oral anti-Xa reversal. We will discuss recent studies in each area to explore the dosing, efficacy, and safety of 4F-PCC.

Association of Plasma Fibrinogen Levels on Postoperative Day 1 with 2-Year Survival of Orthotopic Liver Transplantation for HBV-Related HCC

OBJECTIVE

To clarify the prognostic values of hemostatic parameters to predict the survival of patients undergoing orthotopic liver transplantation (OLT) for hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC).

METHODS

The data of 182 consecutive adult patients who underwent OLT for HBV-related HCC were subjected to univariate and multivariate analyses.

RESULTS

Ascites and fibrinogen levels on postoperative day (POD) 1 were independent predictors of postoperative 2-year mortality (both P <.05). Kaplan-Meier survival analysis showed that the higher the fibrinogen level on POD 1, the better the 1- and 2-year survival of patients with ascites (P <.05), whereas the fibrinogen level on POD 1 was associated with 1-year (P <.05) but not 2-year survival of patients without ascites.

CONCLUSION

Fibrinogen on POD 1 is a predictor of 2-year post-OLT survival of patients with HBV-related HCC with ascites.

Management of Hepatic Coagulopathy in Bleeding and Nonbleeding Patients: An Evidence-Based Review

Patients with varying degrees of hepatic dysfunction often present with presumed bleeding diathesis based on interpretation of routine measures of coagulation (prothrombin time [PT], international normalized ratio [INR], and activated partial thromboplastin time). However, standard markers of coagulation do not reflect the actual bleeding risk in this population and may lead to inappropriate administration of hemostatic agents and blood products. The concept of "rebalanced hemostasis" explains both the risk of bleeding and clotting seen in patients with liver dysfunction. The role of pharmacologic agents and blood products for prevention of bleeding during high-risk procedures and treatment of clinically significant bleeding remains unclear. Viscoelastic measurements of the clotting cascade provide information about platelets, fibrinogen/fibrin polymerization, coagulation factors, and fibrinolysis that might better represent hemostasis in vivo and may better inform management strategies. Due to the paucity of available data, firm recommendations for the use of blood products and pharmacologic agents in patients with hepatic coagulopathies are lacking, and thus, these products should not be routinely administered. Traditional laboratory tests such as PT/INR should not be the sole determinant of potential interventions. Rather, clinicians should assess factors such as the severity of bleed or bleeding risk of the procedure, the patient's risk of thromboembolism, and the strength of available evidence for specific agents and blood products to guide decision-making.