Thromboelastographic reference ranges for a cirrhotic patient population undergoing liver transplantation

Predictors and management of post-banding ulcer bleeding in cirrhosis: A systematic review and meta-analysis

BACKGROUND AND AIMS

Post-banding ulcer bleeding (PBUB) is an understudied complication of oesophageal varices endoscopic band ligation (EBL). This systematic review with meta-analysis aimed at: (a) evaluating the incidence of PBUB in patients with cirrhosis treated with EBL in primary or secondary prophylaxis or urgent treatment for acute variceal bleeding and (b) identifying predictors of PBUB.

METHODS

We conducted a systematic review of articles in English published in 2006-2022 using the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Searches were made in eight databases including Embase, PubMed and Cochrane Library. Random-effects meta-analysis was used to determine the incidence, mean interval and predictors of PBUB.

RESULTS

Eighteen studies (9034 patients) were included. The incidence of PBUB was 5.5% (95% CI 4.3-7.1). The mean time for it to occur was 11 days (95% CI 9.94-11.97). Model for End-stage Liver Disease (MELD) score (OR 1.162, 95% CI 1.047-1.291) and EBL done in emergency setting (OR 4.902, 95% CI 2.99-8.05) independently predicted post-ligation ulcer bleeding. Treatment included drugs, endoscopic procedures and transjugular intrahepatic portosystemic shunt. Refractory bleeding was treated with self-expandable metallic stents or balloon tamponade. Mortality was on average 22.3% (95% CI 14.1-33.6).

CONCLUSIONS

Patients with high MELD score and receiving EBL in an emergency setting are more prone to develop PBUB. Prognosis is still poor and the best therapeutic strategy to address remains to be ascertained.

Use of viscoelastic tests in the principle bleeding scenarios in Spanish hospitals

Viscoelastic tests are designed to study the dynamics of clot formation, identify coagulopathies in real time, arrive at a diagnosis, and guide patient-specific administration of haemostatics. They are mainly used to treat clinically significant bleeding in any setting, and are also used in other situations involving clinically relevant alterations in haemostasis, such as coagulopathy in critically ill patients. These tests are administered following evidence-based algorithms that vary depending on the clinical context. This review summarises the results of a survey conducted in several hospitals to determine the prevalence and standardisation of viscoelastic tests in cardiac surgery, liver transplantation, and multiple trauma patients in Spain. The results reveal divergent opinions on key aspects, ranging from the diagnostic capacity of these tests to the interpretation of the basic parameters. On the basis of these findings, we propose a number of potential areas in which further research will improve the performance of these tests.

Child-Pugh Class and Not Thrombocytopenia Impacts the Risk of Complications of Endoscopic Band Ligation in Patients with Cirrhosis and High Risk Varices

Background and Aims: Endoscopic band legation (EBL) is an effective method for the prophylaxis of acute variceal bleeding (AVB). This procedure may be associated with several complications, particularly bleeding. Our analysis aimed to evaluate the risk of complications due to EBL in a cohort of patients who underwent EBL for the prophylaxis of variceal bleeding and the eventual presence of risk predictors. Patients and Methods: We retrospectively analysed data from consecutive patients who underwent EBL in a primary prophylaxis regimen. For all patients, simultaneously with EBL, we recorded the Child-Pugh and MELD score, platelet count and US features of portal hypertension. Results: We collected data from 431 patients who performed a total of 1028 EBLs. We recorded 86 events (8.4% of all procedures). Bleeding after EBL occurred 64 times (6.2% of all procedures), with the following distribution: intraprocedural bleeding in 4%; hematocystis formation in 17 cases (1.7%); 6 events (0.6%) of AVB due to post-EBL ulcers. None of these events presented a correlation with platelet count (84,235 ± 54,175 × 10³/mL vs. 77,804 ± 75,949 × 10³/mL; p = 0.70) or with the condition of severe thrombocitopenia established at PLT < 50,000/mmc (22.7% with PLT ≤ 50,000/mmc vs. 15.9% with PLT ≥ 50,000/mmc; p = 0.39). Our results showed a relationship between cumulative complications of EBL and Child-Pugh score (6.9 ± 1.6 vs. 6.5 ± 1.3; p = 0.043). Conclusions: EBL in cirrhotic patients is a safe procedure. The risk of adverse events depends on the severity of liver disease, without a relationship with platelet count.

The importance of liver function assessment before cardiac surgery: A narrative review

The demand for cardiac surgery procedures is increasing globally. Thanks to an improvement in survival driven by medical advances, patients with liver disease undergo cardiac surgery more often. Liver disease is associated with the development of heart failure, especially in patients with advanced cirrhosis. Cardiovascular risk factors can also contribute to the development of both cardiomyopathy and liver disease and heart failure itself can worsen liver function. Despite the risk that liver disease and cirrhosis represent for the perioperative management of patients who undergo cardiac surgery, liver function is often not included in common risk scores for preoperative evaluation. These patients have worse short and long-term survival when compared with other cardiac surgery populations. Preoperative evaluation of liver function, postoperative management and close postoperative follow-up are crucial for avoiding complications and improving results. In the present narrative review, we discuss the pathophysiological components related with postoperative complications and mortality in patients with liver disease who undergo cardiac surgery and provide recommendations for the perioperative management.

Consensus Statement on Hemostatic Management, Anticoagulation, and Antiplatelet Therapy in Liver Transplantation

Anticoagulation and antiplatelet therapies are increasingly used in liver transplant (LT) candidates and recipients due to cardiovascular comorbidities, portal vein thrombosis, or to manage posttransplant complications. The implementation of the new direct-acting oral anticoagulants and the recently developed antiplatelet drugs is a great challenge for transplant teams worldwide, as their activity must be monitored and their complications managed, in the absence of robust scientific evidence. In this changing and clinically heterogeneous scenario, the Spanish Society of Liver Transplantation and the Spanish Society of Thrombosis and Haemostasis aimed to achieve consensus regarding the indications, drugs, dosing, and timing of anticoagulation and antiplatelet therapies initiated from the inclusion of the patient on the waiting list to post-LT surveillance. A multidisciplinary group of experts composed by transplant hepatologists, surgeons, hematologists, transplant-specialized anesthesiologists, and intensivists performed a comprehensive review of the literature and identified 21 clinically relevant questions using the patient-intervention-comparison-outcome format. A preliminary list of recommendations was drafted and further validated using a modified Delphi approach by a panel of 24 transplant delegates, each representing a LT institution in Spain. The present consensus statement contains the key recommendations together with the core supporting scientific evidence, which will provide guidance for improved and more homogeneous clinical decision making.

Pro-Con Debate: Viscoelastic Hemostatic Assays Should Replace Fixed Ratio Massive Transfusion Protocols in Trauma

Major trauma patients at risk of traumatic coagulopathy are commonly treated with early clotting factor replacement to maintain hemostasis and prevent microvascular bleeding. In the United States, trauma transfusions are often dosed by empiric, low-ratio massive transfusion protocols, which pair plasma and platelets in some ratio relative to the red cells, such as the "1:1:1" combination of 1 units of red cells, 1 unit of plasma, and 1 donor's worth of pooled platelets. Empiric transfusion increases the rate of overtransfusion when unnecessary blood products are administered based on a formula and not on at patient's hemostatic profile. Viscoelastic hemostatic assays (VHAs) are point-of-care hemostatic assays that provided detailed information about abnormal clotting pathways. VHAs are used at many centers to better target hemostatic therapies in trauma. This Pro/Con section will address whether VHA guidance should replace empiric fixed ratio protocols in major trauma.

Case Report of a Patient Treated With Acenocumarol Awaiting Orthotopic Liver Transplant: Perioperative Coagulation Management and Risk for Hepatic Artery Thrombosis

BACKGROUND

End-stage liver disease is associated with a concomitant reduction of pro- and anticoagulant factors that typically leads to rebalanced hemostasis. This rebalanced hemostasis can be easily disturbed, encountering both hemostasis-related bleeding episodes and thrombotic events.

METHODS

This article reports a case of a 52-year-old man diagnosed with portal vein thrombosis and treated with Acenocumarol. The patient received ortothopic liver transplant. The preprocedure international normalized ratio was 3.5. A transfusion of 2000 units of prothrombin complex concentrate was indicated by Hematology.

RESULTS

Repeated intra- and postoperative hepatic artery thrombosis resulted in graft loss and patient retransplantation in first 24 hours.

CONCLUSIONS

The new concept of rebalanced hemostasis in these patients forces us to change our clinical decisions in preoperative coagulation management, avoiding old practices based on the traditional model such as transfusion guided by international normalized ratio and platelet count, among others that will be analyzed in present work.

Establishment of Normal Range for Thromboelastography in Healthy Middle-Aged and Elderly People of Weihai in China

TEG can monitor the dynamic changes of blood clot formation and lysis by activating the coagulation system of a small sample of whole blood in vitro. The parameters can reflect the level of coagulation factors, the function of fibrinogen and platelet, and the presence or absence of hyperfibrinolysis. At present, the normal reference range of the parameters of TEG is mainly based on the reference values established by the Western population. Due to the differences in the distribution of ethnic groups, many countries have established their reference ranges for healthy populations. In China, some scholars have tried to establish the corresponding TEG reference range according to the characteristics of the population in different regions. This study tried to establish the reference range for thromboelastography in healthy middle-aged and elderly people of Weihai in China and compare it with the reference range provided by the manufacturer. The fasting venous blood of 454 healthy middle-aged and elderly people was collected, including 239 males and 215 females. The thromboelastography TEG-5000 was used to measure the reaction time (R), coagulation formation time (K), coagulation angle (Angle), and maximum amplitude (MA). The reference range of TEG parameters of middle-aged and elderly healthy males was R: 4.38–8.27 min, K: 1.44–2.82 min, Angle: 48.53–72.17 deg, and MA: 51.95–72.02 mm; respectively, in the females, the normal value was R: 3.43–7.40 min, K: 1.07–2.53 min, Angle: 48.22–77.22 deg, and MA: 53.10–74.58 mm; The difference of R, K, Angle, and MA between the male group and the female group was statistically significant (P < 0.05); In this study, if we use the reference range established by the manufacturer, the R specificity for males was 91.6%, K specificity was 98.7%, Angle specificity was 85.8%, and MA specificity was 93.7%; the range for females was 68.4%, 99.5%, 75.8%, and 87.4%, respectively. There are statistically significant differences between R, K, Angle, and MA in middle-aged and elderly healthy women and men. It is necessary to establish a TEG reference range for healthy females and males.

The effect of a viscoelastic-guided bleeding algorithm implementation on blood products use in adult liver transplant patients. A propensity score-matched before-after study

BACKGROUND

Perioperative blood products transfusion is correlated with increased morbidity and mortality in liver transplantation (LTx). The objectives of our study are to assess the effect of a standardized viscoelastic test (VET)-guided bleeding management algorithm implementation on intraoperative bleeding, allogenic blood products and factor concentrates requirements and on early postoperative complications in LTx.

METHODS

Retrospective before-after study comparing two matched cohorts of patients undergoing LTx before (control cohort) and after (intervention cohort) the implementation of a VET-based bleeding algorithm in a single center academic hospital.

RESULTS

After propensity score matching, we included 94 patients in each cohort. Patients in intervention cohort received significantly less blood products, fresh frozen plasma (FFP), and cryoprecipitate (p < 0.001 for each), while the amount of fibrinogen concentrate used was significantly higher (p < 0.001). Postoperatively, intervention cohort patients had significantly lower postoperative hemoglobin and fibrinogen levels and longer prothrombin time compared to control cohort. There were no significant differences in red blood cells transfusions, intraoperative bleeding, early postoperative complications, and short term survival.

CONCLUSIONS

The implementation of a VET-guided bleeding algorithm decreases allogenic blood products requirements, mainly FFP use and allows a more restrictive management of coagulopathy in patients with chronic liver disease undergoing LTx.

A multicenter analysis of the role of prophylactic transfusion of blood products in patients with cirrhosis and esophageal varices undergoing endoscopic band ligation

Background & Aims

Prophylactic administration of platelets and fresh frozen plasma (FFP) has been recommended in patients with cirrhosis with low platelets and/or prolonged international normalized ratio (INR) without scientific evidence to support this practice. In this analysis, we evaluated the use of prophylactic administration of blood products in outpatients with cirrhosis undergoing endoscopic band ligation (EBL).

Methods

This is a multicenter retrospective analysis of consecutive EBL procedures in patients with cirrhosis at 4 hospitals in Spain from 01/2010-01/2017. FFP and/or platelet transfusion were given at the discretion of the physician if INR was >1.5 and/or platelet count <50x10⁹/L. Patient demographics, endoscopic findings, bleeding events after EBL, and the use of prophylactic FFP or platelets were recorded.

Results

A total of 536 patients underwent 1,472 EBL procedures: 72% male; main etiology HCV and alcohol (72%); median MELD score 11; Child-Pugh A/B/C (59/33/8%). EBL procedures were performed for primary (51%) or secondary (49%) prophylaxis. A median of 2 procedures per patient were performed.^1-4 FFP and/or platelets were administered in 41 patients (7.6%). The prophylactic transfusion protocol was followed in 16% and 28% of procedures with high INR and/or low platelets, respectively. Post-EBL bleeding occurred in 26 out of 536 patients (4.8%) and in 33 out of 1,472 procedures (2.2%). Bleeding was due to post-EBL ulcers in 21 patients and due to band dislodgment in 5. In 6 patients, bleeding occurred within 24 hours and in the remaining patients it occurred within 2 weeks after EBL. In those that bled, 7 met criteria for transfusion (2 for FFP and 5 for platelets), of whom only 1 received FFP and 4 received platelets; the remaining 19 patients did not meet criteria for transfusion. There was no association between INR or platelet count and bleeding events. Univariate and multivariate analysis revealed that Child-Pugh and MELD scores were risk factors for post-EBL bleeding.

Conclusions

The incidence of post-EBL bleeding is low and is associated with advanced liver disease. Post-EBL bleeding was not related to baseline INR/platelet count and most outpatients with post-EBL bleeding did not meet criteria for prophylactic transfusion.

Lay summary

Patients with chronic liver disease or cirrhosis and enlarged veins (varices) of the esophagus that can potentially bleed commonly need an endoscopy to treat these varices with elastic rubber bands (endoscopic band ligation). Some patients have low platelet counts or prolonged coagulation tests. This analysis of 4 centers evaluated the use of prophylactic administration of blood products in outpatients with cirrhosis undergoing endoscopic band ligation. The results showed that bleeding after band ligation is uncommon and that if bleeding occurs it does not seem to be related with coagulation tests or the administration of blood products to prevent bleeding after band ligation of esophageal varices.

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Multicenter analysis of prophylactic administration of blood products in 536 outpatients with cirrhosis undergoing EBL.

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The prophylactic transfusion protocol was only followed in 16% and 28% of procedures with high INR and/or low platelets, respectively.

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Post EBL-bleeding occurred in 26 patients – 4.8% of patients and in 2.2% of procedures.

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Patients that bled had higher Child-Pugh and MELD scores compared to those that did not bleed.

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There was no clear relationship between post-EBL bleeding and the baseline INR/platelet count before the procedure.

Invasive Procedures in Patients with Cirrhosis: A Clinical Approach Based on Current Evidence

The aim on of this article is to provide an update on the coagulation disturbances of patients with cirrhosis. It summarizes basic concepts of coagulation in cirrhosis, available tests used to predict bleeding, procedures and risk of bleeding, and the rationale and expert-based recommendations of prophylactic measures for patients with cirrhosis who undergo invasive procedures.

Thrombocytopenia and Hemostatic Changes in Acute and Chronic Liver Disease: Pathophysiology, Clinical and Laboratory Features, and Management

Thrombocytopenia, defined as a platelet count <150,000/μL, is the most common complication of advanced liver disease or cirrhosis with an incidence of up to 75%. A decrease in platelet count can be the first presenting sign and tends to be proportionally related to the severity of hepatic failure. The pathophysiology of thrombocytopenia in liver disease is multifactorial, including (i) splenomegaly and subsequently increased splenic sequestration of circulating platelets, (ii) reduced hepatic synthesis of thrombopoietin with missing stimulation both of megakaryocytopoiesis and thrombocytopoiesis, resulting in diminished platelet production and release from the bone marrow, and (iii) increased platelet destruction or consumption. Among these pathologies, the decrease in thrombopoietin synthesis has been identified as a central mechanism. Two newly licensed oral thrombopoietin mimetics/receptor agonists, avatrombopag and lusutrombopag, are now available for targeted treatment of thrombocytopenia in patients with advanced liver disease, who are undergoing invasive procedures. This review summarizes recent advances in the understanding of defective but at low level rebalanced hemostasis in stable cirrhosis, discusses clinical consequences and persistent controversial issues related to the inherent bleeding risk, and is focused on a risk-adapted management of thrombocytopenia in patients with chronic liver disease, including a restrictive transfusion regimen.

Comparison of Thromboelastography and Conventional Coagulation Tests in Patients With Severe Liver Disease

OBJECTIVE

Thromboelastography (TEG) may provide rapid and clinically important coagulation information in acutely ill patients with chronic liver disease (CLD). Our objective was to describe the relationship between TEG and conventional coagulation tests (CCTs), which has not been previously explored in this population.

METHODS

In acutely ill patients with severe CLD (Child-Pugh score > 9, category C), we conducted a prospective observational study investigating coagulation assessment as measured by both CCTs and TEG. We used quantile regression to explore 30 associations between TEG parameters and corresponding CCTs. We compared TEG and CCT measures of coagulation initiation, clot formation, clot strength, and fibrinolysis.

RESULTS

We studied 34 patients on a total of 109 occasions. We observed inconsistent associations between TEG and CCT measures of coagulation initiation: TEG (citrated kaolin [CK] assay) standard reaction time and international normalized ratio: R ² = 0.117 (P = .044). Conversely, there were strong and consistent associations between tests of clot formation: TEG (CK) kinetics time and fibrinogen: R ² = 0.202 (P < .0001) and TEG (CK) α angle and fibrinogen 0.263 (P < .0001). We also observed strong associations between tests of clot strength, specifically TEG MA and conventional fibrinogen levels, across all TEG assays: MA (CK) and fibrinogen: R ² = 0.485 (P < .0001). There were no associations between TEG and D-dimer levels.

CONCLUSIONS

In acutely ill patients with CLD, there are strong and consistent associations between TEG measures of clot formation and clot strength and conventional fibrinogen levels. There are weak and/or inconsistent associations between TEG and all other conventional measures of coagulation.

Clinical utility of viscoelastic testing in chronic liver disease: A systematic review

BACKGROUND

Conventional coagulation tests are widely used in chronic liver disease to assess haemostasis and to guide blood product transfusion. This is despite the fact that conventional tests do not reliably separate those with a clinically significant coagulopathy from those who do not. Viscoelastic testing such as thromboelastography (TEG) correlate with bleeding risk and are more accurate in identifying those who will benefit from blood product transfusion. Despite this, viscoelastic tests have not been widely used in patients with chronic liver disease outside the transplant setting.

AIM

To assess the utility of Viscoelastic Testing guided transfusion in chronic liver disease patients presenting with bleeding or who require an invasive procedure.

METHODS

PubMed and Google Scholar searches were performed using the key words “thromboelastography”, “TEG” or “viscoelastic” and “liver transplantation”, “cirrhosis” or “liver disease” and “transfusion”, “haemostasis”, “blood management” or “haemorrhage”. A full text review was undertaken and data was extracted from randomised control trials that evaluated the outcomes of viscoelastic test guided transfusion in those with liver disease. The study subjects, inclusion and exclusion criteria, methods, outcomes and length of follow up were examined. Data was extracted by two independent individuals using a standardized collection form. The risk of bias was assessed in the included studies.

RESULTS

A total of five randomised control trials included in the analysis examined the use of TEG guided blood product transfusion in cirrhosis prior to invasive procedures (n = 118), non-variceal haemorrhage (n = 96), variceal haemorrhage (n = 60) and liver transplantation (n = 28). TEG guided transfusion was effective in all five studies with a statistically significant reduction in overall blood product transfusion compared to standard of care. Four of the five studies reported a significant reduction in transfusion of fresh frozen plasma and platelets. Two studies showed a significant reduction in cryoprecipitate transfusion. No increased risk of bleeding was reported in the three trials where TEG was used perioperatively or prior to an invasive procedure. Two trials in the setting of cirrhotic variceal and non-variceal bleeding showed no difference in control of initial bleeding. In those with variceal bleeding, there was a statistically significant reduction in rate of re-bleeding at 42 d in the TEG arm 10% (vs 26.7% in the standard of care arm P = 0.012). Mortality data reported at various time points for all five trials from 6 wk up to 3 years was not statistically different between each arm. One trial in the setting of non-variceal bleeding demonstrated a significant reduction in adverse transfusion events in the TEG arm 30.6% (vs 74.5% in the control arm P < 0.01). In this study there was no significant difference in total hospital stay although length of stay in intensive care unit was reduced by an average of 2 d in the TEG arm (P = 0.012).

CONCLUSION

Viscoelastic testing has been shown to reduce blood product usage in chronic liver disease without compromising safety and may enable guidelines to be developed to ensure patients with liver disease are optimally managed.

New Uses for Thromboelastography and Other Forms of Viscoelastic Monitoring in the Emergency Department: A Narrative Review

Patients frequently visit the emergency department with conditions that place them at risk of worse outcomes when accompanied by coagulopathy. Routine tests of coagulation-prothrombin time, partial thromboplastin time, platelets, and fibrinogen-have shortcomings that limit their use in providing emergency care. One alternative is to investigate coagulation disturbance with viscoelastic monitoring (VEM), a coagulation test that measures the timing and strength of blood clot development in real time. VEM is widely used and studied in cardiac surgery, liver transplant surgery, anesthesia, and trauma. In this article, we review the technique of VEM and the biologic rationale of using it in addition to routine tests of coagulation in emergency clinical situations. Then, we review the evidence (or lack thereof) for using VEM in the diagnosis and treatment of specific conditions. Finally, we describe the limitations of the test and future directions for clinical use and research in emergency medicine.

Thromboelastography Better Reflects Hemostatic Abnormalities in Cirrhotics Compared With the International Normalized Ratio

GOAL

The goal of this study was to describe potential key differences in thromboelastography (TEG) variables in hospitalized cirrhotics compared with a healthy population, identify patterns of hematologic disturbance with disease progression, and assess the value of traditional tests such as international normalized ratio (INR) and platelet count to determine coagulopathy in cirrhotics.

BACKGROUND

TEG, a functional assay of coagulation, has emerged as a useful tool for predicting bleeding risk in cirrhosis.

STUDY

Hospitalized cirrhotics who received a TEG before any blood products between January 2017 and February 2018 at a liver transplant center were included. Reaction time (r-time), coagulation time (k-time), angle-rate of clot polymerization (α) and maximum clot strength (maximum amplitude) were measured with kaolin-activated citrated blood TEG assays.

RESULTS

A total of 106 cirrhotic patients (Child-Turcotte-Pugh A, B, C; n=25, 25, 56) were identified for comparison against data from 53 healthy controls. TEG parameters in cirrhotics were statistically different from controls. Mean INR and platelet count for all cirrhotics were largely outside the normal reference range, contrary to TEG parameters which demonstrated parameters mostly within the normal reference ranges. The r-time, k-time, and α values in the cirrhotics progressively increased and maximum amplitude values progressively decreased as the liver disease progressed. Regression analysis showed no significant correlations between INR and r-time across any Child-Turcotte-Pugh class (r=0.01, 0.18, 0.23; P=0.95, 0.39, 0.08, respectively).

CONCLUSIONS

Although cirrhotics had TEG parameters within normal ranges, there was a propensity for decreased clot formation as liver function worsened. Importantly, the INR did not correlate with TEG parameters in cirrhotic patients, and given the precarious hemostatic balance in these patients, a TEG may be a better predictor of bleeding risk.

Standard coagulation tests are superior to thromboelastometry in predicting outcome of patients with liver cirrhosis

Background and aims

Thromboelastometry (TEM) is superior to standard coagulation tests in the management of bleedings / invasive procedures in patients with liver cirrhosis. In contrast, the role of TEM as a prognostic parameter in liver cirrhosis is not well established. We therefore aimed to assess the role of TEM in predicting survival of outpatients with liver cirrhosis.

Methods

TEM was performed in consecutive outpatients with liver cirrhosis admitted in 2018 and 2019 to the University Hospital Essen. Associations with transplant-free survival were assessed in regression models.

Results

A number of 145 outpatients with liver cirrhosis were included, of whom 27 received a liver transplant (N = 7) or died (N = 20) within 6 months of follow-up. None of the TEM values was associated with transplant-free survival in this cohort. However, as expected, the classical coagulation tests INR (OR = 8.69 (95% CI 1.63–46.48), P = 0.01), PTT (OR = 1.15 (95% CI 1.04–1.27), P<0.01), as well as antithrombin (OR = 0.96 (95% CI 0.94–0.99), P<0.01), and protein C (OR = 0.96 (95% CI 0.92–0.99), P<0.01) were significantly associated with transplant-free survival.

Conclusion

In contrast to the superiority of TEM over classical coagulation tests to guide transfusion of blood products in patients with liver cirrhosis, TEM has no relevance in predicting mortality in outpatients with liver cirrhosis.

Normothermic Machine Perfusion Enhances Intraoperative Hepatocellular Synthetic Capacity: A Propensity Score-matched Analysis

BACKGROUND

Normothermic machine perfusion (NMP) of liver grafts is increasingly being incorporated in clinical practice. Current evidence has shown NMP plays a role in reconditioning the synthetic and energy capabilities of grafts. Intraoperative coagulation profile is a surrogate of graft quality and preservation status; however, to date this aspect has not been documented.

METHODS

The liver transplantation recipients who received NMP liver grafts in the QEHB between 2013 and 2016 were compared in terms of intraoperative thromboelastography characteristics (R time, K time, α-angle, maximum amplitude, G value, and LY30) to a propensity score-matched control group, where the grafts were preserved by traditional static cold storage (SCS).

RESULTS

After propensity matching, none of the thromboelastography characteristics were found to differ significantly between the 72 pairs of SCS and NMP organs when measured preimplantation. However, postimplantation, NMP organs had significantly shorter K time (median: 2.8 vs 3.6 min, P = 0.010) and R + K time (11.4 vs 13.7 min, P = 0.016), as well as significantly larger α-angle (55.9° vs 44.8°, P = 0.002), maximum amplitude (53.5 vs 49.6 mm, P = 0.044), and G values (5.8 vs 4.9k dynes/cm, P = 0.043) than SCS organs. Hyperfibrinolysis after implantation was also mitigated by NMP, with fewer patients requiring aggressive factor correction during surgery (LY30 = 0, NMP vs SCS: 83% vs 60%, P = 0.004). Consequently, NMP organs required significantly fewer platelet units to be transfused during the transplant procedure (median: 0 vs 5, P = 0.001).

CONCLUSIONS

In this study, we have shown that NMP liver grafts return better coagulation profiles intraoperatively, which could be attributed to the preservation of liver grafts under physiological conditions.

Thromboelastography-Guided Blood Component Use in Patients With Cirrhosis With Nonvariceal Bleeding: A Randomized Controlled Trial

Thromboelastography (TEG) provides a more comprehensive global coagulation assessment than routine tests (international normalized ratio [INR] and platelet [PLT] count), and its use may avoid unnecessary blood component transfusion in patients with advanced cirrhosis and significant coagulopathy who have nonvariceal upper gastrointestinal (GI) bleeding. A total of 96 patients with significant coagulopathy (defined in this study as INR >1.8 and/or PLT count < 50 × 10⁹ /L) and nonvariceal upper GI bleed (diagnosed after doing upper gastrointestinal endoscopy, which showed ongoing bleed from a nonvariceal source) were randomly allocated to TEG-guided transfusion strategy (TEG group; n = 49) or standard-of-care (SOC) group (n = 47). In the TEG group, only 26.5% patients were transfused with all three blood components (fresh frozen plasma [FFP], PLTs, and cryoprecipitate) versus 87.2% in the SOC group (P < 0.001). Although 7 (14.3%) patients in the TEG group received no blood component transfusion, there were no such patients in the SOC group (P = 0.012). Also, there was a significantly lower use of blood components (FFP, PLTs, and cryoprecipitate) in the TEG group compared with the SOC group. Failure to control bleed, failure to prevent rebleeds, and mortality between the two groups were similar. Conclusion: In patients with advanced cirrhosis with coagulopathy and nonvariceal upper GI bleeding, TEG-guided transfusion strategy leads to a significantly lower use of blood components compared with SOC (transfusion guided by INR and PLT count), without an increase in failure to control bleed, failure to prevent rebleed, and mortality.

Anticoagulation in the cirrhotic patient

In the past, patients with liver cirrhosis were thought to be prone to increased bleeding risk. However, those with compensated liver cirrhosis actually have normal coagulative balance, which can become altered when liver function worsens, or infection, bleeding, or acute kidney insufficiency occur. When this happens, it is now recognized that patients with liver cirrhosis are at higher risk of thrombotic rather than haemorrhagic complications. Anticoagulation plays a favourable role both when used therapeutically or prophylactically. Successful anticoagulation is associated with a lower rate of decompensation and with improved survival. To date, treatment has involved the use of low molecular weight heparins and vitamin K antagonists. Preliminary data suggest that novel non-vitamin K antagonist oral anticoagulants can be used safely in patients with liver cirrhosis.

Effect of Liver Disease Etiology on ROTEM Profiles in Patients Undergoing Liver Transplantation

BACKGROUND

Coagulation abnormalities in liver transplant patients are complex and may be related to the underlying liver disease. We evaluated the effects of disease etiology on whole-blood rotational thromboelastometry (ROTEM; Pentapharm GmbH, Munich, Germany) profile and association with thrombotic complications following liver transplantation.

METHODS

Analysis of perioperative data from patients undergoing liver transplantation between January 1, 2012 and December 31, 2016. Patients were grouped based on the biology of their underlying liver disease: hepatocellular carcinoma (HCC), biliary etiology, and non-biliary etiology. The primary outcome was the EXTEM A10 value of the pre-incision ROTEM. Secondary outcomes included associations between EXTEM A10 value and incidence of postoperative thrombotic complications.

RESULTS

Three hundred fifty patients met the eligibility criteria: 60 had biliary etiologies, 203 had non-biliary etiologies, and 87 had HCC. EXTEM A10 values were significantly higher in patients with biliary etiologies than those with non-biliary etiologies (mean difference, 13.8; 95% CI: 10.1 to 17.5; P = .001) and those with HCC (mean difference, 10.4; 95% CI: 6.2 to 14.7; P = .001). Patients with non-biliary etiologies had slightly higher values than those with HCC (mean difference, -3.3; 95% CI: -6.6 to -0.1; P = .04). Higher values for biliary etiologies remained after adjusting for liver disease severity, platelet count, and fibrinogen level. There was no significant difference in EXTEM A10 values between patients who suffered thrombotic complications and those who did not (mean difference: 4.3, 95% CI: -1.3 to 9.9, P = .13).

CONCLUSION

Patients with biliary diseases demonstrated higher EXTEM A10 values compared to those with non-biliary diseases or HCC. This was not fully explained by differences in disease severity, platelet count, or fibrinogen level. Pre-incision EXTEM A10 values do not predict incidence of postoperative thrombotic complications.

Coagulation Failure in Patients With Acute-on-Chronic Liver Failure and Decompensated Cirrhosis: Beyond the International Normalized Ratio

Balanced hemostasis with hypocoagulable and hypercoagulable features may occur in acute-on-chronic liver failure (ACLF). The characteristics and prognostic impact of the coagulation profile in ACLF are unknown. Consecutive patients with ACLF (n = 36) and acute decompensation (AD; n = 24) were included. Blood samples for thromboelastometry (TE) were obtained at admission and 72 hours thereafter. The coagulation profile was evaluated in patients with and without ACLF and in those with and without systemic inflammatory response syndrome. The impact of the coagulation profile on transfusion requirements, bleeding events, and short-term survival was assessed. At admission, patients with ACLF showed more hypocoagulable characteristics compared to AD subjects, with prolonged time to initial fibrin formation and clot formation time and decreased maximum clot firmness and alpha-angle values. TE parameters worsened at 72 hours in ACLF but improved in patients with AD. Prevalence of a hypocoagulable profile (three or more TE parameters outside range) was significantly higher in patients with ACLF either at admission (61% versus 29% in AD; P = 0.03) or during follow-up. Hypocoagulability correlated with systemic inflammation and was associated with higher 28-day (45% versus 16%; P = 0.02) and 90-day (52% versus 19%; P = 0.01) mortality rates but not with transfusion requirements or bleeding. Prolonged time to initial fibrin formation (extrinsic TE assay >80 seconds) and Model for End-Stage Liver Disease score at baseline were independent predictors of 28-day mortality. Conclusion: Patients with ACLF frequently show hypocoagulable features with prolonged time to initial fibrin formation and clot formation time and reduced clot firmness; these alterations worsen after admission, correlate with systemic inflammation, and translate into higher short-term mortality; hypofibrinolysis could contribute to organ failure in ACLF.

Thromboelastography Parameters in Patients with Acute on Chronic Liver Failure

INTRODUCTION AND AIM

Patients with acute on chronic liver failure (ACLF) have abnormal conventional coagulation tests- platelet count and international normalized ratio (INR). Thromboelastography (TEG) is a rapid, point-of-care assay, more comprehensive than platelet count and INR as it assesses for platelet adequacy (number and function), coagulation factors and clot retraction. The aim of the study was to evaluate the TEG parameters in patients with ACLF, chronic liver disease having acute decompensation (AD) and healthy subjects (HC).

MATERIAL AND METHODS

TEG parameters were assessed in patients with ACLF and AD within 24 h of admission. Consecutive patients were included in the study over 12 months. Healthy subjects were recruited as controls.

RESULTS

179 patients were included- 68 ACLF, 53 AD and 58 HC. The mean values of INR in ACLF, AD and HC groups were 2.9 ± 1.4, 1.6 ± 0.4 and 1.1 ± 0.2; P < 0.001. Among TEG parameters - maximum amplitude (MA) was low in ACLF and AD patients as compared with HC (53.8 ± 15, 58.3 ± 13.9 mm and 67.2 ± 12.1 mm, respectively; P < 0.001). Lysis at 30 min (LY30) was high in ACLF patients, as compared to AD and HC (8.6 ± 14.1%, 5.0 ± 9.5% and 4.9 ± 9.8%, respectively; P = 0.060). There were no differences in r time, k time, and alpha angle between groups; normal in >90% patients. There was no difference in TEG parameters between different ACLF grades, whereas CCTs were more deranged with increasing grades of ACLF.

CONCLUSION

Despite abnormal conventional coagulation tests, TEG parameters in ACLF patients are essentially normal, except reduced maximum amplitude. Future studies are needed to explore the utility of TEG in clinical management of ACLF patients.

Review: The Perioperative Use of Thromboelastography for Liver Transplant Patients

Thromboelastography (TEG) is a viscoelastic test that allows rapid evaluation of clot formation and fibrinolysis from a sample of whole blood. TEG is increasingly utilized to guide blood product resuscitation in surgical patients and transfusions for liver transplant patients. Patients with severe liver failure have significant derangement of their clotting function due to impaired production of procoagulant and anticoagulant factors. Traditional coagulation studies are limited by the short time needed for the result and provide little information about the dynamics and strength of clot formation. In addition, traditional coagulation studies do not correlate well with bleeding episodes and may lead to over-transfusion of various blood products. Evidence is less robust regarding the use of TEG for transfusion management decisions in severe liver failure patients awaiting, undergoing, or immediately after liver transplant surgery. However, the available evidence suggests that systematic implementation of TEG rather than traditional coagulation studies results in the administration of fewer blood products without increased mortality or complications. The purpose of this study is to review the literature regarding the use of TEG in liver failure patients prior to liver transplant, intraoperatively, and postoperatively. Additional high-quality randomized controlled studies should be performed to evaluate the use of TEG to guide transfusion decisions, particularly in the postoperative period following liver transplantation.

Perioperative thromboprophylaxis in liver transplant patients

Improvements in surgical and anesthetic procedures have increased patient survival after liver transplantation (LT). However, the perioperative period of LT can still be affected by several complications. Among these, thromboembolic complications (intracardiac thrombosis, pulmonary embolism, hepatic artery and portal vein thrombosis) are relatively common causes of increased morbidity and mortality. The benefit of thromboprophylaxis in general surgical patients has already been established, but it is not the standard of care in LT recipients. LT is associated with a high bleeding risk, as it is performed in a setting of already unstable hemostasis. For this reason, the role of routine perioperative prophylactic anticoagulation is usually restricted. However, recent data have shown that the bleeding tendency of cirrhotic patients is not an expression of an acquired bleeding disorder but rather of coexisting factors (portal hypertension, hypervolemia and infections). Furthermore, in cirrhotic patients, the new paradigm of ‘‘rebalanced hemostasis’’ can easily tip towards hypercoagulability because of the recently described enhanced thrombin generation, procoagulant changes in fibrin structure and platelet hyperreactivity. This new coagulation balance, along with improvements in surgical techniques and critical support, has led to a dramatic reduction in transfusion requirements, and the intraoperative thromboembolic-favoring factors (venous stasis, vessels clamping, surgical injury) have increased the awareness of thrombotic complications and led clinicians to reconsider the limited use of anticoagulants or antiplatelets in the postoperative period of LT.

Anesthesia Management of Modified Ex Vivo Liver Resection and Autotransplantation

Background

Ex situ liver surgery allows liver resection and vascular reconstruction in patients who have liver tumors located in critical sites. Only a small series of studies about ex situ liver surgery is available in the literature. No anesthesia management experience has been previously published. The aim of the currents study was to summarize our experience with anesthetic management of patients during ex vivo liver surgery.

Material/Methods

The first 43 patients who received ex vivo liver surgery between January 2007 and April 2012 were included. A pulmonary artery catheter (PAC), transesophageal echocardiography (TEE), and pulse indicator continuous cardiac output (PiCCO) were used intraoperatively in the patients to monitor the hemodynamic changes. Thromboelastogram and the plasma coagulation test were used to monitor the coagulation changes.

Results

All patients received general anesthesia with rapid sequence induction. The data obtained by PAC, TEE, and PiCOO in these cases showed large changes in hemodynamics during the stages of the first or second vessel reconstruction. The CI decreased about 59%/63% and the MPAP decreased about 49%/37% during the first/second vessel reconstruction. Accurate judgment of the dosage of active drug for vascular support is the key for the stabilization of hemodynamics as quickly as possible. However, a high incidence (35.5%) of prophase fibrinolysis in a long anhepatic phase should be monitored and managed.

Conclusions

Ex vivo liver surgery is no longer experimental and is a therapeutic option for patients with liver cancer in critical sites. Good anesthesia support is an essential element of liver autotransplantation.

Viscoelastic Testing in Liver Disease

Long thought to be hypocoagulable, new evidence suggests cirrhosis patients have "rebalanced" coagulation in the setting of decreased synthesis of both pro- and anti-coagulant factors. Traditional testing like PT/INR reflects only the decreased synthesis of pro-coagulant factors and thus does not correspond to bleeding or clotting risk in this population. In this review, we discuss the use of viscoelastic testing (VET), an assay of global hemostasis in cirrhosis patients. We describe the technique and interpretation of commercially available VET and assess the application of VET in both transplant and non-transplant cirrhosis populations. VET largely correlates well with traditional testing including platelet count and fibrinogen level, however, is potentially less accurate in patients with low fibrinogen levels. VET may be useful in identifying patients at higher risk of hypercoagulable complications post-transplant and reflects changes in hemostasis in decompensated patients. While VET has been associated with decreased transfusión support in multiple studies, the lack of bleeding in patients who avoided prophylactic transfusion suggests a "rescue" rather than prophylactic approach to transfusion may be ideal and further studies with a "rescue" arm are needed. Additional prospective studies of VET should include clinically relevant endpoints of bleeding and thrombosis.

Viscoelastic Monitoring to Guide Hemostatic Resuscitation in Liver Transplantation Surgery

Coagulopathic bleeding must be anticipated during liver transplantation (LT) surgery. Patients with end-stage liver disease (ESLD) often present with disease-related hematologic disturbances, including the loss of hepatic procoagulant and anticoagulant clotting factors and thrombocytopenia. Transplantation surgery itself presents additional hemostatic changes, including hyperfibrinolysis. Viscoelastic monitoring (VEM) is often used to provide targeted, personalized hemostatic therapies for complex bleeding states including cardiac surgery and major trauma. The use in these coagulopathic conditions led to its application to LT, although the mechanisms of coagulopathy in these patients are quite different. While VEM is often used during transplant surgeries in Europe and North America, evidence supporting its use is limited to a few small clinical studies. The theoretical and clinical applications of the standard and specialized VEM assays are discussed in the setting of LT and ESLD.

Bleeding Risk with Invasive Procedures in Patients with Cirrhosis and Coagulopathy

PURPOSE OF REVIEW

Previous perceptions of cirrhosis as a hypocoagulable state have resulted in empirical blood product transfusions prior to invasive procedures. We evaluate procedure-related bleeding risks in patients with cirrhosis, assess the utility of conventional and newer global coagulation tests, and explore evidence surrounding prophylactic transfusion strategies.

RECENT FINDINGS

Recent literature supports the concept of a rebalanced, albeit fragile, haemostasis equilibrium in cirrhosis, with a potential hypercoagulable tendency in stable patients. Standard coagulation tests provide a poor reflection of bleeding risks and yet are relied upon for transfusion thresholds. Consequently, a sizeable proportion of patients receive unnecessary blood products. The role of viscoelastic tests to guide transfusions requires further evaluation. In stable cirrhotic patients, procedure-related bleeding rates appear low. Prophylactic transfusion strategies based on arbitrary thresholds lack evidence of clinical benefit. There is a pressing need for point-of-care coagulation tests that represent the complex coagulopathy of cirrhosis and well-powered randomised controlled trials to develop evidence-based pre-procedure transfusion guidelines.

Pathogenesis, prevention, and management of bleeding and thrombosis in patients with liver diseases

Patients with liver diseases may develop alterations in all components of the hemostatic system. Thrombocytopenia, low levels of coagulation factors and inhibitors, low levels of fibrinolytic proteins, and increased levels of endothelial-derived proteins such as von Willebrand factor are all part of the coagulopathy of liver disease. Due to concomitant changes in pro- and antihemostatic drivers, the net effects of these complex hemostatic changes have long been unclear. According to current concepts, the hemostatic system of patients with liver disease is in an unstable balance, which explains the occurrence of both bleeding and thrombotic complications. This review will discuss etiology and management of bleeding and thrombosis in liver disease and will outline unsolved clinical questions. In addition, we will discuss the role of intrahepatic activation of coagulation for progression of liver disease, a novel paradigm with potential consequences for the general management of patients with liver disease.