Hemostasis and thrombosis in patients with liver disease: the ups and downs

Angiocrine signaling in sinusoidal homeostasis and liver diseases

The hepatic sinusoids are composed of liver sinusoidal endothelial cells (LSECs), which are surrounded by hepatic stellate cells (HSCs) and contain liver-resident macrophages called Kupffer cells, and other patrolling immune cells. All these cells communicate with each other and with hepatocytes to maintain sinusoidal homeostasis and a spectrum of hepatic functions under healthy conditions. Sinusoidal homeostasis is disrupted by metabolites, toxins, viruses, and other pathological factors, leading to liver injury, chronic liver diseases, and cirrhosis. Alterations in hepatic sinusoids are linked to fibrosis progression and portal hypertension. LSECs are crucial regulators of cellular crosstalk within their microenvironment via angiocrine signaling. This review discusses the mechanisms by which angiocrine signaling orchestrates sinusoidal homeostasis, as well as the development of liver diseases. Here, we summarise the crosstalk between LSECs, HSCs, hepatocytes, cholangiocytes, and immune cells in health and disease and comment on potential novel therapeutic methods for treating liver diseases.

A new model of portal vein thrombosis in rats with cirrhosis induced by partial portal vein ligation plus carbon tetrachloride and intervened with rivaroxaban

BACKGROUND AND AIMS

Portal vein thrombosis (PVT) is a common complication of liver cirrhosis that can aggravate portal hypertension. However, there are features of both PVT and cirrhosis that are not recapitulated in most current animal models. In this study, we aimed to establish a stable animal model of PVT and cirrhosis, intervene with anticoagulant, and explore the related mechanism.

METHODS

First, 49 male SD rats received partial portal vein ligation (PPVL), and 44 survival rats were divided into 6 groups: PPVL control group; 4-week, 6 -week, 8-week, and 10-week model group; and the rivaroxaban (RIVA)-treated group. The rats were intoxicated with or without carbon tetrachloride (CCl4) for 4-10 weeks. Seven normal rats were used as the normal controls. Serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels and parameters for blood coagulation were all assayed with kits. Liver inflammation, collagen deposition and hydroxyproline (Hyp) levels were also measured. The extrahepatic macro-PVT was observed via portal vein HE staining, etc. The intrahepatic microthrombi was stained via fibrin immunohistochemistry. The portal blood flow velocity (PBFV) and diameter were detected via color Doppler ultrasound. Vascular endothelial injury was evaluated by von Willebrand Factor (vWF) immunofluorescence. Fibrinolytic activity was estimated by western blot analysis of fibrin and plasminogen activator inhibitor-1 (PAI-1).

RESULTS

After PPVL surgery and 10 weeks of CCl4 intoxication, a rat model that exhibited characteristics of both cirrhosis and extra and intrahepatic thrombi was established. In cirrhotic rats with PVT, the PBFV decreased, both factors of pro- and anti-coagulation decreased, but with relative hypercoagulable state, vascular endothelial injured, and fibrinolytic activity decreased. RIVA-treated rats had improved coagulation function, increased PBFV and attenuated thrombi. This effect was related to the improvements in endothelial injury and fibrinolytic activity.

CONCLUSIONS

A new rat model of PVT with cirrhosis was established through partial portal vein ligation plus CCl4 intoxication, with the characteristics of macrothrombi at portal veins and microthrombi in hepatic sinusoids, as well as liver cirrhosis. Rivaroxaban could attenuate PVT in cirrhosis in the model rats. The underlying mechanisms of PVT formation in the rat model and pharmacological action of rivaroxaban are related to the regulation of portal blood flow, coagulant factors, and vascular endothelial cell function.

Patients with alcohol abuse have higher risks of complications after coronary artery bypass grafting: A population-based study of National Inpatient Sample from 2015 to 2020

BACKGROUND

Alcohol abuse (AA) has s high prevalence, affecting 10 to 15 million Americans. While AA was demonstrated to negatively impact cardiovascular health, limited evidence from existing studies presents conflicting findings regarding the effects of AA on coronary artery bypass grafting (CABG) outcomes. This study aimed to compare the in-hospital outcomes after CABG between AA and non-AA patients.

METHODS

Patients who underwent CABG were identified in National Inpatient Sample from Q4 2015-2020. Exclusion criteria included age<18 years and concomitant procedures. A 1:3 propensity-score matching was used to address differences in demographics, socioeconomic status, primary payer status, hospital characteristics, comorbidities, and transfer/admission status between AA and non-AA patients. In-hospital outcomes after CABG were examined.

RESULTS

There were 5694 (3.39%) AA patients who underwent CABG. After matching, 17,315 from 162,488 non-AA patients were matched to all AA patients. AA and non-AA patients had comparable mortality (1.64% vs 1.55%, p = 0.67) and MACE (2.46% vs 2.56%, p = 0.73). However, AA patients had higher cardiogenic shock (8.31% vs 7.43%, p = 0.03), mechanical ventilation (11.51% vs 7.96%, p < 0.01), hemorrhage/hematoma (57.49% vs 54.75%, p < 0.01), superficial (0.99% vs 0.61%, p < 0.01) and deep wound complications (0.37% vs 0.18%, p = 0.02), reopen surgery for bleeding control (0.92% vs 0.63%, p = 0.03), transfer out (21.00% vs 16.38%, p < 0.01), longer time from admission to operation (p < 0.01), longer length of stay (p < 0.01), and higher hospital charge (p < 0.01).

CONCLUSION

While AA was not found to be linked with in-hospital mortality or MACE after CABG, it was independently associated with postoperative complications. These findings could enhance preoperative risk stratification for AA patients and inform postoperative management following CABG.

Features of thromboelastogram in populations exposed to or transferring from high altitude

Background

Thromboelastogram (TEG) is an effective indicator that monitors the dynamic changes of blood coagulation in real-time. It still remains controversial about the performance and influence of coagulation at high altitude. The present study intends to describe comprehensively the clinical features of TEG in populations exposed to or transferring from high altitude.

Methods

Two groups were recruited in the present study. Group A included young males who worked at high-altitude (4888 m or 5418 m) areas for some time, while Group B included young males who had recently returned from high-altitude (4888 m or 5418 m) areas. Medical examinations were performed using portable devices. Spearman's test was used to evaluate the correlations between thromboelastogram (TEG) variables and other variables. Logistic regression analysis was used to analyze the factors affecting various abnormal TEG variables.

Results

A total of 51 adult males were included in the two groups. Significantly increased reaction time (R) and decreased maximum amplitude (MA) were found in group B (P < 0.05). No significant differences were observed in the comparisons of K and angle between the two groups. Various TEG variables were identified to be correlated with different coagulation and biochemical variables. Logistic regression analysis demonstrated that abnormal R was independently associated with direct bilirubin, and abnormal K was independently associated with the platelet count in Group A (P < 0.05). However, none of the factors were independently associated with abnormal TEG variables in Group B.

Conclusion

Populations exposed to or transferring from high altitudes are characterized by different TEG characteristics. Our findings give a comprehensive description of the complex interaction between TEG indexes, coagulation dynamics, and hematological parameters, which can help guide the development of appropriate medical approaches tailored to the unique needs of these populations.

The evolving knowledge on primary hemostasis in patients with cirrhosis: A comprehensive review

Patients with cirrhosis develop complex alterations in primary hemostasis that include both hypocoagulable and hypercoagulable features. This includes thrombocytopenia, multiple alterations of platelet function, and increased plasma levels of von Willebrand factor. Contrary to the historical view that platelet dysfunction in cirrhosis might be responsible for an increased bleeding tendency, the current theory posits a rebalanced hemostasis in patients with cirrhosis. Severe thrombocytopenia is not indicative of the bleeding risk in patients undergoing invasive procedures and does not dictate per se the need for pre-procedural prophylaxis. A more comprehensive and individualized risk assessment should combine hemostatic impairment, the severity of decompensation and systemic inflammation, and the presence of additional factors that may impair platelet function, such as acute kidney injury and bacterial infections. Although there are multiple, complex alterations of platelet function in cirrhosis, their net effect is not yet fully understood. More investigations evaluating the association between alterations of platelet function and bleeding/thrombosis may improve risk stratification in patients with decompensated cirrhosis. Besides hemostasis, the assessment of von Willebrand factor Ag and ADP-induced, whole-blood platelet aggregation normalized by platelet count (VITRO score and PLT ratio) are promising biomarkers to predict the risk of hepatic decompensation and survival in both compensated and decompensated patients. Further investigations into the in vivo interplay between platelets, circulating blood elements, and endothelial cells may help advance our understanding of cirrhotic coagulopathy. Here, we review the complex changes in platelets and primary hemostasis in cirrhosis and their potential clinical implications.

Predictive value of white blood cell to hemoglobin ratio for 30-day mortality in patients with severe intracerebral hemorrhage

Aim

To explore the predictive value of white blood cell to hemoglobin ratio (WHR) for 30-day mortality in patients with intracerebral hemorrhage (ICH).

Methods

In this cohort study, 2,848 patients with ICH were identified in the Medical Information Mart for Intensive Care (MIMIC)-III and MIMIC-IV. Least absolute shrinkage and selection operator (LASSO) regression screened covariates of 30-day mortality of ICH patients. COX regression analysis was used to study the association of different levels of WHR, white blood cell (WBC), and hemoglobin (Hb) with 30-day mortality. The median follow-up time was 30 (20.28, 30.00) days.

Results

In total, 2,068 participants survived at the end of the follow-up. WHR was negatively correlated with the Glasgow Coma Score (GCS) (spearman correlation coefficient = -0.143, p < 0.001), and positively associated with the Sepsis-related Organ Failure Assessment (SOFA) score (spearman correlation coefficient = 0.156, p < 0.001), quick SOFA (qSOFA) score (spearman correlation coefficient = 0.156, p < 0.001), and Simplified Acute Physiology Score II (SAPS-II) (spearman correlation coefficient = 0.213, p < 0.001). After adjusting for confounders, WHR >0.833 (HR = 1.64, 95%CI: 1.39-1.92) and WBC >10.9 K/uL (HR = 1.49, 95%CI: 1.28-1.73) were associated with increased risk of 30-day mortality of patients with ICH. The area under the curve (AUC) value of the prediction model based on WHR and other predictors was 0.78 (95%CI: 0.77-0.79), which was higher than SAPSII (AUC = 0.75, 95%CI: 0.74-0.76), SOFA score (AUC = 0.69, 95%CI: 0.68-0.70) and GCS (AUC = 0.59, 95%CI: 0.57-0.60).

Conclusion

The level of WHR was associated with 30-day mortality in patients with severe ICH, and the WHR-based prediction model might provide a tool to quickly predict 30-day mortality in patients with ICH.

Consumptive coagulopathy in the ICU

A consumptive coagulopathy describes a situation where there is a loss of hemostatic factors, which leads to an increased risk of bleeding. Some recent studies have used the term interchangeably with disseminated intravascular coagulation (DIC), but we have reverted to the older definition, which covers a broader range of issues where there is loss of hemostatic factors due to multiple causes, which includes systemic activation of coagulation as seen in DIC. Therefore, the term consumptive coagulopathy covers conditions from the hemostatic effects of major hemorrhage to the use of extracorporeal circuits to true DIC. We review the current understanding of the pathophysiology, diagnosis, and management of common consumptive coagulopathy in critical care patients, focusing on recent advances and controversies. Particular emphasis is given to DIC because it is a common and often life-threatening condition in critical care patients and is characterized by the simultaneous occurrence of widespread microvascular thrombosis and bleeding. Second, we focus on the effect of modern medical technology, such as extracorporeal membrane oxygenation, on hemostasis.

TEG-based transfusion protocol is associated with decreased blood product use without increased risk of hemoperitoneum

BACKGROUND

Thromboelastography (TEG) informs the need for blood product transfusions to prevent procedural bleeding complications in patients with cirrhosis. We aimed to evaluate the impact of using a TEG-based transfusion protocol on blood product utilization before paracentesis and the post-paracentesis hemoperitoneum (PPH) incidence.

METHODS

We conducted an ambispective analysis of patients with cirrhosis who underwent paracentesis from 2017 to 2021. In May 2019, we enacted a TEG-based transfusion protocol to guide pre-paracentesis blood product use. Patients with platelets < 20,000 or international normalized ratio ≥ 4 underwent TEG and received blood products if r value > 10 min or MA <30 mm. Patients were divided into pre-TEG and post-TEG protocol cohorts based on the date of paracentesis. Pre-paracentesis blood product transfusions in the form of platelets, fresh frozen plasma, and cryoprecipitates were recorded. PPH was defined as a decrease in hemoglobin of ≥1 g and the presence of blood on diagnostic imaging and/or the need for therapeutic intervention.

RESULTS

A total of 483 patients underwent 1281 paracenteses. The main etiologies of cirrhosis were alcohol (43%) and NASH (25%), and the mean MELD-sodium was 22±6. Pre-TEG and post-TEG protocol cohort sizes were similar: 253 patients and 607 paracenteses versus 230 patients and 674 paracenteses. After TEG-protocol implementation, blood product transfusions decreased significantly (228 vs. 49 products, p<0.001) with associated cost savings. One patient in each cohort developed PPH.

CONCLUSION

Implementation of a pre-paracentesis TEG-based transfusion protocol for patients with cirrhosis successfully resulted in decreased blood product use with no associated increase in incidence of PPH.

Spontaneous Rupture of the Internal Thoracic Artery Causing a Mediastinal Hematoma in a Patient with Alcoholic Liver Cirrhosis: A Case Report

Spontaneous arterial bleeding is uncommon, and a mediastinal hematoma caused by spontaneous rupture of the internal thoracic artery has not been reported previously. Patients with liver cirrhosis or heavy alcohol consumption have a higher risk of hemorrhage than those without cirrhosis or excessive alcohol consumption. We present the case of a 39-year-old female with a history of alcoholic liver cirrhosis, who presented with a large mediastinal hematoma attributable to spontaneous rupture of the internal thoracic artery.

Machine learning-based prediction of cerebral hemorrhage in patients with hemodialysis: A multicenter, retrospective study

Background

Intracerebral hemorrhage (ICH) is one of the most serious complications in patients with chronic kidney disease undergoing long-term hemodialysis. It has high mortality and disability rates and imposes a serious economic burden on the patient's family and society. An early prediction of ICH is essential for timely intervention and improving prognosis. This study aims to build an interpretable machine learning-based model to predict the risk of ICH in patients undergoing hemodialysis.

Methods

The clinical data of 393 patients with end-stage kidney disease undergoing hemodialysis at three different centers between August 2014 and August 2022 were retrospectively analyzed. A total of 70% of the samples were randomly selected as the training set, and the remaining 30% were used as the validation set. Five machine learning (ML) algorithms, namely, support vector machine (SVM), extreme gradient boosting (XGB), complement Naïve Bayes (CNB), K-nearest neighbor (KNN), and logistic regression (LR), were used to develop a model to predict the risk of ICH in patients with uremia undergoing long-term hemodialysis. In addition, the area under the curve (AUC) values were evaluated to compare the performance of each algorithmic model. Global and individual interpretive analyses of the model were performed using importance ranking and Shapley additive explanations (SHAP) in the training set.

Results

A total of 73 patients undergoing hemodialysis developed spontaneous ICH among the 393 patients included in the study. The AUC of SVM, CNB, KNN, LR, and XGB models in the validation dataset were 0.725 (95% CI: 0.610 ~ 0.841), 0.797 (95% CI: 0.690 ~ 0.905), 0.675 (95% CI: 0.560 ~ 0.789), 0.922 (95% CI: 0.862 ~ 0.981), and 0.979 (95% CI: 0.953 ~ 1.000), respectively. Therefore, the XGBoost model had the best performance among the five algorithms. SHAP analysis revealed that the levels of LDL, HDL, CRP, and HGB and pre-hemodialysis blood pressure were the most important factors.

Conclusion

The XGB model developed in this study can efficiently predict the risk of a cerebral hemorrhage in patients with uremia undergoing long-term hemodialysis and can help clinicians to make more individualized and rational clinical decisions. ICH events in patients undergoing maintenance hemodialysis (MHD) are associated with serum LDL, HDL, CRP, HGB, and pre-hemodialysis SBP levels.

Predicting the Occurrence of Advanced Schistosomiasis Based on FISHER Discriminant Analysis of Hematological Biomarkers

We established a model that predicts the possibility of chronic schistosomiasis (CS) patients developing into advanced schistosomiasis (AS) patients using special biomarkers that were detected in human peripheral blood. Blood biomarkers from two cohorts (132 CS cases and 139 AS cases) were examined and data were collected and analyzed by univariate and multivariate logistic regression analysis. Fisher discriminant analysis (FDA) for advanced schistosomiasis was established based on specific predictive diagnostic indicators and its accuracy was assessed using data of 109 CS. The results showed that seven indicators including HGB, MON, GLB, GGT, APTT, VIII, and Fbg match the model. The accuracy of the FDA was assessed by cross-validation, and 86.7% of the participants were correctly classified into AS and CS groups. Blood biomarker data from 109 CS patients were converted into the discriminant function to determine the possibility of occurrence of AS. The results demonstrated that the possibility of occurrence of AS and CS was 62.1% and 89.0%, respectively, and the accuracy of the established model was 81.4%. Evidence displayed that Fisher discriminant analysis is a reliable predictive model in the clinical field. It’s an important guide to effectively control the occurrence of AS and lay a solid foundation for achieving the goal of schistosomiasis elimination.

Global hemostatic profiling in patients with decompensated cirrhosis and bacterial infections

Background & Aims

Bacterial infections in cirrhosis are associated with increased bleeding risk. To assess the factors responsible for bleeding tendency in patients with bacterial infections, we conducted a prospective study comparing all 3 aspects of hemostasis (platelets, coagulation, and fibrinolysis) in hospitalized patients with decompensated cirrhosis with vs. without bacterial infections.

Methods

Primary hemostasis assessment included whole blood platelet aggregation and von Willebrand factor (VWF). Coagulation assessment included procoagulant factors (fibrinogen, factor II, V, VII, VIII, IX, X, XI, XII, XIII), natural anticoagulants (protein C, protein S, antithrombin) and thrombomodulin-modified thrombin generation test. Fibrinolysis assessment included fibrinolytic factors (plasminogen, t-PA, PAI-1, α2-AP, TAFIa/ai) and plasmin-antiplasmin complex (PAP).

Results

Eighty patients with decompensated cirrhosis were included (40 with and 40 without bacterial infections). Severity of cirrhosis and platelet count were comparable between groups. At baseline, patients with cirrhosis and bacterial infections had significantly lower whole blood platelet aggregation, without significant differences in VWF. Regarding coagulation, bacterial infections were associated with reduced procoagulant factors VII and XII, and a significant reduction of all natural anticoagulants. However, thrombomodulin-modified thrombin generation was comparable between the study groups. Finally, although mixed potentially hypo-fibrinolytic (lower plasminogen) and hyper-fibrinolytic (higher t-PA) changes were present in bacterial infections, a comparable level of PAP was detected in both groups. Upon resolution of infection (n = 29/40), platelet aggregation further deteriorated whereas coagulation and fibrinolysis factors returned to levels observed in patients without bacterial infections.

Conclusion

In hospitalized patients with decompensated cirrhosis, bacterial infections are associated with reduced whole blood platelet aggregation and a significant decrease of all natural anticoagulants, which may unbalance hemostasis and potentially increase the risk of both bleeding and thrombosis.

Lay summary

Bacterial infections are a common issue in hospitalized patients with decompensated cirrhosis (i.e. patients hospitalized due to severe complications of advanced chronic liver disease). Patients with decompensated cirrhosis who acquire infections may be at increased risk of bleeding complications following invasive procedures (that is a procedure in which the body is penetrated or entered, for instance by a needle or a tube). As bleeding complications in decompensated cirrhosis are associated with a high risk of further decompensation and death, there is an urgent need to understand the factors responsible for such increased bleeding tendency. Herein, we investigated the alterations of hemostasis (that is the physiological process responsible for clot formation and stability) in patients with decompensated cirrhosis and bacterial infections. We found that development of bacterial infections in these patients is associated with alterations of hemostasis (particularly of platelets and clotting cascade) that may increase the risk of both bleeding and thrombotic complications.

Relationship of Anatomic Variations and Arterial Reconstruction of the Hepatic Artery: Prevalence and Effect on Orthotopic Liver Transplantation

BACKGROUND

Identifying anatomic variations of the hepatic artery is essential in liver transplantation. The artery supply is crucial for the procedure's success, and, in some cases of anatomic variations, they need reconstruction. Hepatic artery thrombosis is a severe vascular complication. This study evaluated the prevalence of anatomic variations and correlated arterial reconstructions with hepatic artery thrombosis.

METHODS

We performed a retrospective analysis of medical records, adult patients undergoing liver transplant, donor's arterial anatomy, arterial reconstructions, and thrombosis after transplant from January 2019 to December 2020.

RESULTS

Among 226 cases, 71% had normal anatomy. All these patients met Michel's classification subtypes, of which 161 (71%) were class I, which is the most common. The second most common variation was class II, with 25 donors (11%), followed by class III, with 17 donors (7.5%). Anatomic artery variations were a risk factor for hepatic artery thrombosis development (odds ratio [OR], 7.2; 95% confidence interval [CI], 2.1-22.5; P = .002). In the same way, the artery reconstruction was associated with hepatic artery thrombosis arising with postoperative time (OR, 18.0; 95% CI, 4.9-57.5; P < .001). Global hepatic artery thrombosis occurred in 11 cases (4.87%).

CONCLUSION

Anatomic hepatic artery variations are frequent and do not make liver transplant unfeasible. However, variations that require reconstruction may raise the risk of thrombosis.

Haemostatic alterations and management of haemostasis in patients with cirrhosis

Patients with cirrhosis frequently acquire complex changes in their haemostatic system including a decreased platelet count and decreased levels of various haemostatic proteins. Although historically patients with cirrhosis were thought to have a haemostasis-related bleeding tendency, it is now widely accepted that the haemostatic system of patients with cirrhosis remains in balance as a result of simultaneous changes in pro- and anti-haemostatic systems. The concept of rebalanced haemostasis has led to changes in clinical management, although firm evidence from well-designed clinical studies is largely lacking. For example, many invasive procedures in patients with cirrhosis and a prolonged prothrombin time are now performed without prophylaxis with fresh frozen plasma. Conversely, clinicians have become more aware of the need for anti-thrombotic therapy, even in those patients with abnormal routine coagulation tests. This paper will outline recent advances in pathogenesis, prevention and treatment of both bleeding and thrombotic complications in patients with cirrhosis. Among other topics, we will discuss the haemostatic status of acutely ill patients with cirrhosis, the various causes of bleeding in patients with cirrhosis, and how best to prevent or treat bleeding. In addition, we will discuss the hypercoagulable features of patients with cirrhosis, new insights into the pathogenesis of portal vein thrombosis, and how best to prevent or treat thromboses.

A Comparative Analysis of Catheter Directed Thrombolysis with Anticoagulation Alone or Systemic tPA in Acute Pulmonary Embolism with Cor Pulmonale

Background

Pulmonary embolism (PE) with cor pulmonale causes considerable mortality and morbidity. Randomized trials have failed to show a mortality difference between treatment modalities including anticoagulation (AC), Catheter directed thrombolysis (CDT) and systemic tPA (tissue plasminogen activator).

Methods

This is a cross-sectional retrospective case-control study utilizing the 2017 National Inpatient Sample (NIS). Patients admitted with acute PE with cor pulmonale were divided into groups based on whether they received anticoagulation, CDT or systemic tPA based on appropriate ICD-10 PCS codes. The AC group and CDT group were compared using univariate and multivariate analyses after adjusting for age, gender, race, comorbidities, insurance status and Charlson comorbidity index (CCI). Secondary outcomes included factors influencing length of stay (LOS) and total charges incurred. Similar analyses were done to compare the CDT group with the tPA group.

Results

In 2017, 13240 patients were admitted with acute PE and cor pulmonale, of whom 18% underwent CDT, 10% underwent systemic tPA and 72% underwent AC alone. Patients who received CDT over AC alone were significantly younger (61.5 vs. 65.5, p = 0.00). Mortality rate overall was 4.8% with tPA group, CDT group and AC alone group having a 11.2%, 3.0% and 4.4% mortality rate respectively. On multivariate analyses, there was no significant mortality difference between the CDT and AC groups (aOR 0.61, 0.34-1.1 95%CI, p = 0.103). Patients with liver disease had significantly higher mortality while obese patients had a significantly lower mortality after adjusting for treatment strategy and confounders. Length of stay (LOS) was not significantly different between the groups however, compared to AC alone, patients who underwent CDT or tPA incurred significantly higher total hospital charges.

Conclusions

CDT offers an attractive alternative to tPA therapy; however, our study does not show an in-hospital mortality benefit. More studies are required to guide patient selection prior to establishing treatment protocols.

Principles, Interpretation, and Evidence-Based Role of Viscoelastic Point-of-Care Coagulation Assays in Cirrhosis and Liver Failure

Background and Aims

Standard coagulation tests such as prothrombin time, activated partial thromboplastin time, and international normalized ratio are determined by liver-synthesized coagulation factors. Despite an increased international normalized ratio, patients with cirrhosis are in a "rebalanced" state of hemostasis as the concomitant effect of reduced protein C, protein S, and thrombomodulin is not evaluated in standard coagulation tests. The cell-based model of hemostasis indicates additional mechanisms such as systemic inflammation, sepsis, and organ failures tip the delicate coagulation balance to an anticoagulant type in acute-on-chronic liver failure. In acute liver failure, thrombin generation and platelet function remain intact despite a marked prolongation in prothrombin time. We aimed to explain the principles, application, and utility of viscoelastic tests such as thromboelastography, rotational thromboelastometry, and Sonoclot.

Methods

We reviewed the available literature from MEDLINE, EMBASE and the Cochrane Central Register of Controlled Trial with the search terms 'coagulation', 'cirrhosis', 'acute-on-chronic liver failure', 'thromboelastography', 'thromboelastometry' and 'sonoclot' for cross sectional studies, cohort studies and randomized trials.

Results

The point-of-care viscoelastic tests provide actionable targets for correcting the coagulation defect in a patient with bleeding and provide evidence-based algorithms for use in liver disease. A limitation of these tests is the inability to assess vessel injury and endothelial elements.

Conclusion

Global coagulation tests provide a comprehensive estimate of coagulation in vitro; however, their use has only been validated in the setting of liver transplantation. Newer guidelines for hemostatic resuscitation are now accepting these POC tests, but additional data are required to validate their use as standard of care.

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.

Resistance to thrombomodulin correlates with liver stiffness in chronic liver disease a prospective single-center cohort study

INTRODUCTION

Chronic liver disease (CLD) is characterized by changes in haemostasis, embracing both hypo- and hypercoagulability. Global hemostatic tests such as thrombin generation assays evaluate the hemostatic balance, to better assess bleeding and thrombotic risks. In addition, procoagulant state in patients with CLD has been demonstrated using modified thrombin generation assays with thrombomodulin, a cofactor for protein C activation. In this study, we prospectively determined thrombin generation and thrombomodulin resistance in patients with CLD staged with liver stiffness measurement (LSM), using both the fully automated analyzer ST Genesia® Thrombin Generation System (STG) and the calibrated automated thrombogram assay (CAT).

MATERIALS AND METHODS

Demographic, clinical and laboratory characteristics, and blood samples were collected from 65 patients with CLD. Liver stiffness was measured by transient elastography, and thrombin generation and thrombomodulin resistance, by STG and CAT.

RESULTS

Patients were separated based on LSM of <21 and ≥21 kilopascals (kPa). The propagation rate of thrombin generation was higher in patients with LSM ≥21 kPa and the thrombin generation rate increased as LSM increased. In addition, thrombomodulin resistance assessed by STG and CAT was higher in patients with LSM ≥21 kPa. However, ETP inhibition by activated protein C was comparable in patients with LSM <21 and ≥21 kPa. Finally, LSM correlated with most thrombin generation parameters.

CONCLUSION

The STG automated system may have value in the assessment of patients with chronic liver disease in the routine coagulation laboratory. LSM ≥21 kPa identify a procoagulant phenotype in these patients, including thrombomodulin resistance.

Altered von Willebrand Factor and ADAMTS13 Levels in Children With Cirrhosis and Extrahepatic Portal Hypertension

BACKGROUND/AIM

This study was concerned with whether vWF (von Willebrand factor) and a disintegrin and metalloprotease with a thrombospondin type 1 motif, member 13 (ADAMTS13) has altered in patients with cirrhosis and extrahepatic portal hypertension (EPH). We aimed to investigate changes to vWF and ADAMTS13 in children with cirrhosis and EPH.

PATIENTS AND METHODS

This study was conducted between January and October 2019 with both cirrhosis and EPH patients and with healthy volunteers. The von Willebrand factor antigen (vWF:Ag), von Willebrand Ristocetin cofactor (vWF:RCo), and ADAMTS13 antigen and activity were studied.

RESULTS

Twenty-eight children with cirrhosis, 16 children with EPH, and 20 healthy controls were included in the study. vWF:Ag and vWF:RCo levels were higher in patients with cirrhosis than in healthy controls (171.65±101.67 vs. 85.86±30.58, P<0.01 and 121.62±55.83 vs. 61.52±27.03, P<0.01, respectively). vWF:Ag and vWF:RCo levels were higher in patients with EPH than in healthy controls (133.93±80.13 vs. 85.86±30.58, P<0.01 and 103.18±58.55 vs. 61.52±27.03, P=0.02, respectively). The ADAMTS13 antigen and activity levels were lower in patients with cirrhosis than in healthy controls (0.58±0.23 vs. 0.97±0.15, P<0.01 and 49.91±22.43 vs. 86.51±22.07, P=0.02, respectively). The ADAMTS13 antigen and activity levels were lower in patients with EPH than in healthy controls (0.69±0.11 vs. 0.97±0.15, P=0.03; and 68.50±13.29 vs. 86.51±22.07, P=0.02, respectively). The increase in vWF and the decrease in ADAMTS13 were more pronounced in cirrhotic patients with autoimmune hepatitis (AIH) than in non-AIH patients.

CONCLUSIONS

While levels of vWF:Ag and vWF:RCo increased in children with cirrhosis and EPH, levels of the ADAMTS13 antigen and ADAMTS13 activity decreased. These alterations were more pronounced in patients with AIH-derived cirrhosis.

More Pronounced Hypercoagulable State and Hypofibrinolysis in Patients With Cirrhosis With Versus Without HCC

In patients with cirrhosis, particularly those with hepatocellular carcinoma (HCC), hypercoagulability may be associated with purported increased risks of portal vein thrombosis and cirrhosis progression. In this study, we extensively investigated hemostatic alterations potentially responsible for the thrombotic tendency in HCC, and evaluated whether such alterations were predictive of hepatic decompensation. Patients with cirrhosis at all stages were prospectively recruited and underwent an extensive hemostatic assessment, including all procoagulant factors and inhibitors, thrombin generation with and without thrombomodulin (TG), profibrinolytic and antifibrinolytic factors, and plasmin‐antiplasmin complex. In study part 1 (case control), we compared alterations of coagulation and fibrinolysis in patients with cirrhosis with versus without HCC. In study part 2 (prospective), the subgroup of patients with decompensated cirrhosis was followed for development of further decompensation, and predictors of outcome were assessed by multivariate analysis. One‐hundred patients were recruited (50 each with and without HCC). Severity of cirrhosis was comparable between groups. Median HCC volume was 9 cm³ (range: 5‐16). Compared with controls, patients with HCC demonstrated a significantly more prothrombotic hemostatic profile due to increased TG and reduced activation of fibrinolysis, independent of cirrhosis stage. During a median follow‐up of 175 days, 20 patients with decompensated cirrhosis developed further episodes of decompensation that were predicted by low FVII and high plasminogen activator inhibitor‐1 levels, independent of Model for End‐Stage Liver Disease score. Conclusion: Patients with cirrhosis with HCC have profound hyper‐coagulable changes that can account for their increased thrombotic tendency. In contrast, hypercoagulability in patients with decompensated cirrhosis is more likely a consequence of chronic liver disease rather than a driver for cirrhosis progression.

Gastrointestinal endoscopy in cirrhotic patient: Issues on the table

Patients with liver cirrhosis are fragile and present specific clinical hallmarks. When undergoing to gastrointestinal (GI) endoscopy, these subjects require an individual pre evaluation, taking into account: Level of haemostasis impairment, the individual risk of infection, the impact of sedation on hepatic encephalopathy and other factors. The overall assessment of liver function, employing common scoring systems, should be also assessed in the preprocedural phase. Beside some common general problems, regarding GI endoscopy in cirrhotic subjects, also specific issues are present for some frequent indications or procedures. For instance, despite an increased incidence of adenomas in cirrhosis, colon cancer screening remains suboptimal in subjects with this disease. Several studies in fact demonstrated liver cirrhosis as a negative factor for an adequate colon cleansing before colonoscopy. On the other hand, also the routine assessment of gastroesophageal varices during upper GI endoscopy presents some concern, since important inter-observer variability or incomplete description of endoscopic findings has been reported in some studies. In this review we discussed in details the most relevant issues that may be considered while performing general GI endoscopic practice, in patient with cirrhosis. For most of these issues there are no guidelines or clear indications. Moreover until now, few studies focused on these aspects. We believe that targeting these issues with corrective measures may be helpful to develop a tailored endoscopic approach for cirrhosis, in the future.

Association of thromboelastography profile with severity of liver cirrhosis and portal venous system thrombosis

BACKGROUND AND AIM

Hemostasis profile is often complicated in liver cirrhosis. Thromboelastography is a global viscoelastic test recommended by the current practice guideline and consensus. This cross-sectional study aimed to evaluate the association of thromboelastography profile with severity of liver cirrhosis and presence of portal venous system thrombosis (PVST).

METHODS

Overall, 116 and 50 cirrhotic patients were included in the Shenyang and Xi'an cohorts, respectively. Thromboelastography parameters were compared between cirrhotic patients with Child-Pugh class A and B/C, those with and without decompensated events, and those with and without PVST. Hypercoagulability would be considered if at least two of the following thromboelastography parameters were met: shortened reactive time (R), shortened coagulation time (K), increased angle, and increased maximum amplitude (MA).

RESULTS

In the Shenyang cohort, 16 patients had shortened R, of whom seven (43.75%) had prolonged K and 11 (68.75%) decreased MA. In the Xi'an cohort, 24 patients had shortened R, of whom seven (29.17%) had prolonged K and 15 (62.50%) decreased MA. In the Shenyang cohort, the prevalence of hypercoagulability was not significantly different between cirrhotic patients with Child-Pugh class A and B/C (3.85% vs. 6.25%, P = 0.873), those with and without decompensated events (5.49% vs. 4.00%, P = 1.000), and those with and without PVST (4.17% vs. 5.88%, P = 1.000), which were similar to the results obtained in the Xi'an cohort.

CONCLUSION

There is a high rate of discordance between R and other thromboelastography parameters. In addition, hypercoagulability may not be related to more advanced stage of liver cirrhosis or presence of PVST.

Association of thromboelastography profile with severity of liver cirrhosis and portal venous system thrombosis

BACKGROUND AND AIM

Hemostasis profile is often complicated in liver cirrhosis. Thromboelastography is a global viscoelastic test recommended by the current practice guideline and consensus. This cross-sectional study aimed to evaluate the association of thromboelastography profile with severity of liver cirrhosis and presence of portal venous system thrombosis (PVST).

METHODS

Overall, 116 and 50 cirrhotic patients were included in the Shenyang and Xi'an cohorts, respectively. Thromboelastography parameters were compared between cirrhotic patients with Child-Pugh class A and B/C, those with and without decompensated events, and those with and without PVST. Hypercoagulability would be considered if at least two of the following thromboelastography parameters were met: shortened reactive time (R), shortened coagulation time (K), increased angle, and increased maximum amplitude (MA).

RESULTS

In the Shenyang cohort, 16 patients had shortened R, of whom seven (43.75%) had prolonged K and 11 (68.75%) decreased MA. In the Xi'an cohort, 24 patients had shortened R, of whom seven (29.17%) had prolonged K and 15 (62.50%) decreased MA. In the Shenyang cohort, the prevalence of hypercoagulability was not significantly different between cirrhotic patients with Child-Pugh class A and B/C (3.85% vs. 6.25%, P = 0.873), those with and without decompensated events (5.49% vs. 4.00%, P = 1.000), and those with and without PVST (4.17% vs. 5.88%, P = 1.000), which were similar to the results obtained in the Xi'an cohort.

CONCLUSION

There is a high rate of discordance between R and other thromboelastography parameters. In addition, hypercoagulability may not be related to more advanced stage of liver cirrhosis or presence of PVST.

Assessment of laboratory tests and intraoperative bleeding in patients with liver cirrhosis undergoing tooth extractions

OBJECTIVES

The objective of this study was to quantify intraoperative bleeding in patients with cirrhosis and correlate it with clinical characteristics and laboratory coagulation tests.

STUDY DESIGN

A case-control study was carried out with 74 patients with cirrhosis who were submitted to preoperative coagulation tests (complete blood count, platelet count, prothrombin time/international normalized ratio, thrombin time, activated partial thrombin time, platelet aggregation, fibrinogen, protein C, protein S, antithrombin, and von Willebrand factor level and activity). The levels of nitrogen compounds that can affect the platelet function were determined in saliva and blood by using automated enzymatic-colorimetric assays.

RESULTS

Patients with cirrhosis had changes in almost all coagulation tests. The average volumes of intraoperative bleeding and blood lost per minute in the study group (5.36 mL/min and 0.19 mL/min, respectively) were greater than those in the control group (3.05 mL/min and 0.11 mL/min, respectively; P < .05). In the control group, ascites (P = .012) and presence of periapical lesion (0.034) were positively correlated with bleeding (mL/min). With regard to coagulation tests and nitrogen compounds, only a positively moderate correlation with the platelet aggregation test was observed.

CONCLUSIONS

No patients had hemorrhagic events and it was not possible to correlate a greater amount of bleeding with coagulation tests or nitrogen compounds in the study group.

Exploring the Complex Role of Coagulation Factor VIII in Chronic Liver Disease

Chronic liver disease is one of the leading causes of death in the United States. Coagulopathy is often a sequela of chronic liver disease, however, the role and regulation of coagulation components in chronic liver injury remain poorly understood. Clinical and experimental evidence indicate that misexpression of the procoagulant factor VIII (FVIII) is associated with chronic liver disease. Nevertheless, the molecular mechanism of FVIII-induced chronic liver injury progression remains unknown. This review provides evidence supporting a pathologic role for FVIII in the development of chronic liver disease using both experimental and clinical models.

Platelet activation and hypercoagulability in patients with early primary biliary cholangitis compared with healthy controls

Background

Patients with primary biliary cholangitis (PBC) who have advanced disease are hypercoagulable, with no thrombophilic factors compared to non-cholestatic cirrhotics. We investigated whether hypercoagulability is present in early-stage PBC.

Methods

PBC patients with biopsy-documented early disease and healthy controls matched by sex and age were asked to participate in the study. All were evaluated using rotational thromboelastometry (ROTEM), platelet aggregation, and flow cytometry. Four ROTEM parameters were evaluated (clotting time, clotting formation time, α-angle, and maximum clot firmness [MCF]). Platelet aggregation was determined as the maximal change in light transmission after the addition of adenosine diphosphate, collagen and epinephrine. Flow cytometry was used to evaluate the expression of glycoprotein (GP) IIb, GPIIa, and P-selectin on the platelet surface.

Results

We enrolled 50 individuals in the study (25 PBC patients, 25 controls). Prothrombin time and activated partial thromboplastin time did not differ significantly between PBC patients and controls (P-value not significant). In ROTEM, aaaaaaaa-angle and MCF parameters were abnormally elevated in 9 (36%) PBC patients compared to 3 (12%) healthy controls and the difference was statistically significant (P=0.026). Platelet aggregation in PBC patients was not significantly different from controls. In flow cytometry, GPIIb and P-selectin expression was greater in PBC patients than in the control group and the difference was statistically significant (P=0.005 and P=0.006 respectively).

Conclusion

In this study, we used a combination of sophisticated methods to detect evidence of platelet activation and hypercoagulability in patients with early PBC. Our findings may have important clinical implications and merit further investigation.

Risk factors associated with bleeding after prophylactic endoscopic variceal ligation in cirrhosis

BACKGROUND

Prophylactic endoscopic variceal band ligation (EVL) is frequently performed in patients with liver cirrhosis. The aim of our study was to identify factors associated with early upper gastrointestinal bleeding (UGIB) in cirrhosis patients after prophylactic EVL.

METHODS

787 nonemergency EVLs performed in 444 patients in two German University medical centers were analyzed retrospectively.

RESULTS

Within 30 days after EVL, 38 UGIBs were observed (4.8 % of all procedures). Bilirubin levels (hazard ratio [HR] 1.5, 95 % confidence interval [CI] 1.2-2.0 for a 2-fold increase) and presence of varices grade III/IV according to Paquet (HR 2.6, 95 %CI 1.3-5.0 compared with absence or smaller sized varices) were independently associated with UGIB following EVL. International normalized ratio (INR) was associated with bleeding events in the univariate analysis but did not reach statistical significance after adjustment for bilirubin and presence of varices grade III/IV (HR 1.2, 95 %CI 0.9-1.6 for an increase by 0.25). There was no statistically significant association between platelet count or fibrinogen levels and UGIB. Substitution of coagulation products did not affect incidence of bleeding after EVL, which also applied to patients with "coagulopathy" (INR > 1.5 and/or platelet count < 50 × 10⁹/L). No association between proton pump inhibitor therapy and post-EVL UGIB was observed.

CONCLUSIONS

EVL is a safe procedure and immediate bleeding complications are rare. Serum bilirubin levels and size of varices, rather than coagulation indices, are associated with UGIB after EVL. Our data do not support the preventive substitution of blood or coagulation products.

Efficacy of intraoperative cine-portogram for complicated portal vein reconstruction in pediatric living donor liver transplantation

Sufficient PV flow is necessary to achieve successful PV reconstruction in pediatric LDLT. IOCP can be used to assess the severity of PV stenosis and to identify potential portosystemic collateral pathways. The present study reviewed the utility of IOCP and the outcomes of patients who underwent assessment with an IOCP. Consecutive primary LDLTs were performed in 488 pediatric recipients between November 2005 and October 2019. IOCP was used in patients who were unable to achieve sufficient PV flow after the ligation of collaterals. In total, 11 patients underwent IOCP to assess potential portosystemic collateral pathways. The median age and body weight was 8 months (IQR, 6-11 months) and 6.6 kg (IQR, 5.7-8.9 kg), respectively. The reasons for using the IOCP were recurrent PV thrombus in seven patients and insufficient PV flow in four patients. IOCP revealed remaining collaterals in six patients and residual hypoplastic PV in eight patients. Two patients required additional interruption of the potential collaterals under IOCP, which were unable to be recognized as a dominant portosystemic collateral pathway on preoperative imaging. All eight patients with residual hypoplastic PV required vein graft interposition for the complete removal of the hypoplastic PV. All the patients are currently doing well with a median follow-up period of 4.9 years (IQR, 2.2-5.6 years). IOCP can be an effective tool for precisely detecting occult portosystemic collateral pathways and for assessing the patency of the PV anastomosis in pediatric LDLT.

Fibrinogen Replacement Therapy for Traumatic Coagulopathy: Does the Fibrinogen Source Matter?

Fibrinogen is the first coagulation protein to reach critically low levels during traumatic haemorrhage. There have been no differential effects on clinical outcomes between the two main sources of fibrinogen replacement: cryoprecipitate and fibrinogen concentrate (Fg-C). However, the constituents of these sources are very different. The aim of this study was to determine whether these give rise to any differences in clot stability that may occur during trauma haemorrhage. Fibrinogen deficient plasma (FDP) was spiked with fibrinogen from cryoprecipitate or Fg-C. A panel of coagulation factors, rotational thromboelastography (ROTEM), thrombin generation (TG), clot lysis and confocal microscopy were performed to measure clot strength and stability. Increasing concentrations of fibrinogen from Fg-C or cryoprecipitate added to FDP strongly correlated with Clauss fibrinogen, demonstrating good recovery of fibrinogen (r² = 0.99). A marked increase in Factor VIII, XIII and α₂-antiplasmin was observed in cryoprecipitate (p < 0.05). Increasing concentrations of fibrinogen from both sources were strongly correlated with ROTEM parameters (r² = 0.78-0.98). Cryoprecipitate therapy improved TG potential, increased fibrinolytic resistance and formed more homogeneous fibrin clots, compared to Fg-C. In summary, our data indicate that cryoprecipitate may be a superior source of fibrinogen to successfully control bleeding in trauma coagulopathy. However, these different products require evaluation in a clinical setting.

Reduced Clot Stability by Thromboelastography as a Potential Indicator of Procedure-Related Bleeding in Decompensated Cirrhosis

In patients with decompensated cirrhosis, procedure-related bleeding is a potentially lethal complication. Routine coagulation tests such as international normalized ratio and platelet count do not predict bleeding risk. We investigated whether thromboelastography (TEG) can identify patients with cirrhosis who are at risk of procedure-related bleeding. As a part of a prospective study on hemostasis in decompensated cirrhosis, patients had TEG performed on admission and were followed prospectively during hospitalization for the development of procedure-related bleeding. Eighty patients with cirrhosis were included. Among the 72 who had procedures performed, 7 had procedure-related bleeding, which was major in three cases (two following paracentesis and one following thoracentesis). Conventional coagulation tests were comparable between bleeding and nonbleeding patients, whereas TEG parameters of k-time (4.5 minutes vs. 2.2 minutes; P = 0.02), α-angle (34° vs. 59°; P = 0.003), and maximum amplitude (37 mm vs. 50 mm; P = 0.004) were significantly different (all indicative of hypocoagulability). TEG maximum amplitude (MA), a marker of overall clot stability, accurately discriminated between patients who had major, life-threatening bleeding (all with MA < 30 mm) and those who had mild or no bleeding (all with MA > 30 mm), whereas a platelet count < 50 × 109/L could not discriminate between bleeding (minor or major) and nonbleeding patients. Conclusion: In a prospective cohort of hospitalized patients with decompensated cirrhosis, TEG parameters associated with hypocoagulability appeared to predict procedure-related bleeding, particularly a TEG MA < 30 mm. If results are validated in a larger cohort, this could be a threshold to identify patients with decompensated cirrhosis at higher risk for procedure-related bleeding, in whom to consider preprocedural prophylaxis.

Identification of key signaling pathways induced by SARS-CoV2 that underlie thrombosis and vascular injury in COVID-19 patients

The SARS-CoV-2 pandemic has led to hundreds of thousands of deaths and billions of dollars in economic damage. The immune response elicited from this virus is poorly understood. An alarming number of cases have arisen where COVID-19 patients develop complications on top of the symptoms already associated with SARS, such as thrombosis, injuries of vascular system, kidney, and liver, as well as Kawasaki disease. In this review, a bioinformatics approach was used to elucidate the immune response triggered by SARS-CoV-2 infection in primary human lung epithelial and transformed human lung alveolar. Additionally, examined the potential mechanism behind several complications that have been associated with COVID-19 and determined that a specific cytokine storm is leading to excessive neutrophil recruitment. These neutrophils are directly leading to thrombosis, organ damage, and complement activation via neutrophil extracellular trap release.

Anticoagulation in patients with advanced liver disease: an open issue

Liver disease has been long considered as a risk factor for bleeding for the presence of prolongation of global tests of clotting activation and low platelet count. For this reason, the use of anticoagulants in patients with liver disease and an indication to anticoagulation, such as atrial fibrillation of venous thrombosis, has been poorly considered. Furthermore, recent studies underscored the fact that patients with chronic liver disease may experience thrombosis in portal as well as systemic circulation and treatment with anticoagulants should be considered. The introduction of direct oral anticoagulants has increased therapeutic options for thromboprophylaxis; however, evidence on their safety and efficacy in specific populations, such as patients with liver disease, is still scarce and needs further investigation. Thus, atrial fibrillation patients with coexistent liver disease have been excluded from clinical trials with direct oral anticoagulants. Here, we provide an overview on mechanisms of thrombosis in patients with advanced chronic liver disease and a summary of evidence on the use of oral anticoagulants in patients with liver disease and portal vein thrombosis or atrial fibrillation.

Risk of bleeding during oral surgery in patients with liver cirrhosis: A systematic review

BACKGROUND

The liver is responsible for the production of almost all coagulation factors, but does this indicate a risk of developing unusual bleeding in patients with liver cirrhosis during dental surgery?

TYPES OF STUDIES REVIEWED

In this systemic review, the authors followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist and performed a search of PubMed, Latin American and Caribbean Health Sciences Literature, Web of Science, Scopus, and Cochrane databases.

RESULTS

Seven studies met the inclusion criteria. The sample sizes ranged from 23 through 318 participants, number of extracted teeth ranged from 62 through 1,183, platelet count ranged from 16,000 through 216,000 per cubic milimeter, and the international normalized ratio was less than 4. The prevalence of hemorrhagic events in the studies ranged from 0% through 8.9%, and almost all were controlled with local hemostatic measures.

CONCLUSIONS AND PRACTICAL IMPLICATIONS

During dental treatment, patients with liver cirrhosis have a low bleeding risk in spite of the decreased number of platelets and increased international normalized ratio.

Spontaneous hemorrhage after external ventricular drain placement in the setting of low factor VII secondary to liver cirrhosis

Background:

Alterations in normal coagulation and hemostasis are critical issues that require special attention in the neurosurgical patient. These disorders pose unique challenges in the management of these patients who often have concurrent acute ischemic and hemorrhagic injuries. Although neurosurgical intervention in such cases may be unavoidable and potentially life-saving, these patients should be closely observed after instrumentation.

Case Description:

A 57-year-old male with liver cirrhosis secondary to amyloid light-chain amyloidosis was admitted to the intensive care unit for the management of delayed hydrocephalus. An external ventricular drain (EVD) was placed for the treatment and monitoring of hydrocephalus. Five days after EVD placement, a head computed tomography scan revealed a tract hemorrhage. However, on repeated imaging, the size of the hemorrhage continued to increase despite aggressive blood pressure control and several doses of phytonadione. Extensive coagulopathy workup was remarkable for low factor VII levels. In that setting, recombinant activated factor VII was administered to normalize factor VII levels, and the tract hemorrhage stabilized.

Conclusion:

To the best of our knowledge, this is the first case of spontaneous hemorrhage after EVD placement in the setting of liver cirrhosis-associated factor VII deficiency. Our case highlights the importance of identifying coagulation disorders in neurosurgical patients at high risk for coagulopathy and closely monitoring them postoperatively.

Acute and Subacute Toxicity Studies of the Aqueous Extract from Haloxylon scoparium Pomel (Hammada scoparia (Pomel)) by Oral Administration in Rodents

Materials and Methods

Acute toxicity test was performed on Swiss albino mice at a single oral dose of 1-10 g/kg for 14 consecutive days. General behavioral adverse effects, mortality, and latency of mortality were determined. In the subacute study, the Haloxylon scoparium Pomel extract was administered orally at doses of 500, 1000, and 2000 mg/kg daily for 30 days to Wistar rats. Body weight and selected biochemical and hematological parameters were determined at the end of the experiment. Sections of livers and kidneys were removed for histological studies.

Results

Acute toxicity study showed that the oral LD₅₀ value of Haloxylon scoparium Pomel extract was 5000 mg/kg. The subacute toxicity study of Haloxylon scoparium Pomel extract at doses 500, 1000, and 2000 mg/kg did not produce any observable symptoms of toxicity and no significant variation in body weight, organ weights, food, and water consumption or mortality in all treated rats. However, the administration of the Haloxylon scoparium Pomel extract to rats at 500 mg/kg and 1000 mg/kg showed a significant decrease in platelets. Moreover, only at the highest dose (2000 mg/kg), the extract caused a significant increase in red blood cells and hemoglobin. Our results showed that subacute treatments with Haloxylon scoparium Pomel extract at doses of 1000 mg/kg and 2000 mg/kg significantly elevated alkaline phosphatase and triglycerides. Histological studies showed that the subacute treatments of rats with Haloxylon scoparium Pomel extracts, at the doses 1000 and 2000 mg/kg, induced some histopathological changes in the livers but a slight changing in kidneys.

Conclusion

Our results indicated low acute toxicity of the aqueous extract of Haloxylon scoparium Pomel. Furthermore, daily oral administration of Haloxylon scoparium Pomel extract caused some damages to the livers of rats treated with high doses, expressed by an increase in some enzyme activities such as ALP. Regarding the renal function, we did not find remarkable toxicity in the subacute treatment with Haloxylon scoparium Pomel extracts at doses 1000 and 2000 mg/kg. However, further toxicity assessments should be done to ascertain the safety or the toxicity of this valuable plant species “Haloxylon scoparium pomel” in subchronic treatments.

Donor tobacco smoking is associated with postoperative thrombosis after primary liver transplantation

BACKGROUND

Thrombosis after liver transplantation is a leading cause of graft loss, morbidity, and mortality. Several known recipient- and surgery-related characteristics have been associated with increased risk of thrombosis after transplantation. Potential donor-related risk factors, however, remain largely undefined.

OBJECTIVES

We aimed to identify risk factors for early post-transplantation thrombosis (<90 days) and to determine the impact of early postoperative thrombosis on long-term graft and patient survival.

PATIENTS/METHODS

A post hoc analysis was performed of an observational cohort study including all primary, adult liver transplantations performed between 1993 and 2018. Donor-, recipient-, and surgery-related characteristics were collected. Competing risk model analyses and multivariable regression analyses were performed to identify risk factors for developing early post-transplant thrombosis and graft failure.

RESULTS

From a total of 748 adult liver transplantations, 58 recipients (7.8%) developed a thrombosis after a median of 7 days. Post-transplantation thrombotic events included 25 hepatic artery thromboses, 13 portal vein thromboses, and 22 other thrombotic complications. Donor history of smoking was independently associated with early postoperative thrombosis (odds ratio [OR] 2.42; 95% confidence interval [CI], 1.29-4.52). Development of early post-transplant thrombosis was independently associated with patient mortality (hazard ratio [HR] 3.61; 95% CI 1.54-8.46) and graft failure (HR 5.80, 95% CI 3.26-10.33), respectively.

CONCLUSION

Donor history of smoking conveys a more than two-fold increased risk of thrombosis after liver transplantation, independent of other factors. Post-transplant thrombosis was independently associated with decreased patient and graft survival.

Viscoelastic Tests as Point-of-Care Tests in the Assessment and Management of Bleeding and Thrombosis in Liver Disease

Viscoelastic point-of-care (VET POC) tests provide a global assessment of hemostasis and have an increasing role in the management of bleeding and blood component delivery across several clinical settings. VET POC tests have a rapid turnaround time, provide a better overall picture of hemostasis, predict bleeding more accurately than conventional coagulation tests, and reduce blood component usage and health care costs. Despite commonly having abnormal conventional coagulation tests, most patients with chronic liver disease have a "rebalanced" hemostasis. However, this hemostatic balance is delicate and these patients are predisposed to both bleeding and thromboembolic events. Over recent years, VET POC tests have been increasingly studied for their potential as better functional tests of hemostasis in liver disease patients. This review provides a background on the most common VET POC tests (thromboelastography and rotational thromboelastometry) and discusses the current evidence for these tests in the prediction and management of bleeding and thrombosis in patients with chronic liver disease, and in liver resection and transplant. With the recent publication of several randomized controlled trials, there is growing evidence that VET POC tests may be used to improve bleeding risk assessment and reduce blood product use in liver disease patients outside of the transplant setting. However, consensus is still lacking regarding the VET POC tests' thresholds that should be used to trigger blood product transfusion. VET POC tests also show promise in predicting thrombosis in patients with liver disease, but further research is needed before they can be used to guide anticoagulant therapy.

Hypercoagulability (thrombin generation) in patients with cirrhosis is detected with ST-Genesia

BACKGROUND

Thrombin generation assays (TGAs) performed with calibrated automated thrombography (CAT) in the presence of thrombomodulin (TM) indicate plasma hypercoagulability in cirrhosis.

OBJECTIVE

To evaluate, in the presence of TM, the new ST-Genesia automated device developed for improving TGA vs the previously used CAT method, with plasma samples of patients with cirrhosis.

PATIENTS/METHODS

Platelet-poor plasma samples were prepared from citrated blood samples of 52 healthy controls and 85 patients with cirrhosis (severity evaluated using the Child-Pugh score [CP]). TGAs were performed using CAT with PPP-Reagent and ST-Genesia with the STG-ThromboScreen reagent, in the presence of TM. Endogenous thrombin potential (ETP) was chosen as the main parameter.

RESULTS

Whatever the method, ETP values were higher in patients than in healthy controls. All patients identified as hypercoagulable with ST-Genesia and STG-ThromboScreen were found hypercoagulable with CAT and PPP-Reagent. Conversely, eight and ten patients in the CP-A and CP-B classes respectively were identified as hypercoagulable only with CAT. The use of ST-Genesia with the STG-ThromboScreen reagent with TM led to a bias, with higher ETP values for healthy controls and lower for patients compared with CAT. Crossover analysis (CAT with the STG-ThromboScreen reagent) evidenced a substantial effect of the STG-ThromboScreen reagent; the analyzer (including calibration and data analysis) plays a lesser role.

CONCLUSION

ST-Genesia evidences hypercoagulability in patients with cirrhosis when TG is studied in the presence of TM, but the results are not interchangeable with those obtained with CAT.

Approach to the liver transplant early postoperative period: an institutional standpoint

The liver transplant program in our center started in 1992, and post-liver transplant patients are still admitted to the intensive care unit. For the intensive care physician, a learning curve started then, skills were acquired, and a specific practice was established. Throughout this time, several concepts changed, improving the care of these patients. The practical approach varies between liver transplant centers, according to local specificities. Hence, we wanted to present our routine practice to stimulate the debate between dedicated teams, which can allow the introduction of new ideas and potentially improve each local standard of care.

In Vitro Evaluation of Pro- and Anticoagulant Drugs in Children with End-Stage Liver Disease Undergoing Liver Transplantation

Background Pro- and anticoagulant drugs are commonly used in pediatric liver transplantation to prevent and treat thrombotic and bleeding complications. However, the combination of baseline hemostatic changes in children with liver disease and additional changes induced by transplantation makes this very challenging. This study aimed to analyze the efficacy of clinically available pro- and anticoagulant drugs in plasma from children undergoing liver transplantation.

Methods In vitro effects of pro- and anticoagulant drugs on thrombin generation capacity were tested in plasma samples of 20 children (≤ 16 years) with end-stage liver disease undergoing liver transplantation, and compared with 30 age-matched healthy controls.

Results Addition of pooled normal plasma had no effect in patients or controls, while 4-factor prothrombin complex concentrate increased thrombin generation in both patients and controls, with enhanced activity in patients. At start of transplantation, dabigatran and unfractionated heparin had a higher anticoagulant potency in patients, whereas 30 days after transplantation low molecular weight heparin was slightly less effective in patients. Effects of rivaroxaban were comparable between patients and controls.

Conclusion This study revealed important differences in efficacy of commonly used pro- and anticoagulant drugs in children with end-stage liver disease undergoing liver transplantation. Therefore, dose adjustments of these drugs may be required. The results of this study may be helpful in the development of urgently needed protocols for strategies to prevent and treat bleeding and thrombotic complications in pediatric liver transplantation.

Coagulation status of critically ill patients with and without liver disease assessed using a novel thrombin generation analyzer

The liver synthesizes the majority of pro- and anti-coagulant and fibrinolytic proteins, and during liver dysfunction synthesis of these proteins is reduced. The end point of conventional hemostatic tests, such as the prothrombin time (PT), occurs when only 5% of thrombin generation (TG) has taken place and is not sensitive to the effects of natural anti-coagulants. The aim of this study was to determine whether TG in the presence of thrombomodulin (TM) provides more useful information about coagulation potential, in comparison to the PT. Analysis was performed on ST Genesia, a novel TG analyzer from Diagnostica Stago. TG was measured using STG-Thromboscreen, a reagent containing an intermediate concentration of human tissue factor (TF) ± rabbit TM to account for anti-coagulant protein C (PC) activity. Platelet-poor plasma (PPP) samples were from the Intensive Care Study of Coagulopathy-2 (ISOC-2), which recruited patients admitted to critical care with a prolonged PT (3 seconds above the reference range). Despite a prolonged PT, 48.0% and 60.7% of patients in the liver and non-liver groups had TG parameters within the normal range. Addition of TM reduced TG by 34.5% and 41.8% in the liver and non-liver groups, respectively. Interestingly, fresh frozen plasma (FFP) transfusion had no impact on TG. Measurement of TG with addition of TM provides a more informative assessment of coagulation capacity and indicates that hemostasis is balanced in patients with liver disease during critical illness, despite conventional tests suggesting that bleeding risk is increased.

Transfusional optimization in liver transplant using viscoelastic test guided therapy

BACKGROUND

Assess the reduction of packed red blood cells (PRBCs) transfusion in liver transplantation (LT) after the introduction of the thromboelastometry as intraoperative coagulation monitor.

METHODS

We conducted a retrospective cohort study (n=92), randomized into two groups: groupA (control), in whom transfusion therapy was based on conventional laboratory tests (CLT), and groupB (ROTEM), whose blood transfusion was performed as protocolized algorithms, guided by thromboelastometry (ROTEM). We analyzed packed red blood cells (PRBCs) units, transfused units of fresh frozen plasma (FFP), platelets units, fibrinogen and tranexamic acid. We used the chi square test for the comparison of proportions and Student's t test to compare means when the distribution was normal. Otherwise, Mann-Whitney U test was performed.

RESULTS

In groupA 84.8% of patients required transfusion of PRBCs, with a median (IQR) of 4 (1.5-6), compared with 67.4% in groupB with a median (IQR) of 2 (0-4) (P<.05). We also found differences in the following variables: FFP transfusion rate was 84.8% with a median (IQR) of 5 (2-12) IU in groupA and 56.5% (median (IQR) of 1 (0-4.5) in B (P<.001) and in the fibrinogen administration, that was 6.5% in groupA and 34.8% in groupB (P<.01). Backward stepwise logistic regression model showed associations between the clamping time, the preoperative hemoglobin, the portal hypertension (PHT) and being or not in the treatment group and the need for perioperative transfusion. We didn't find significant differences in the incidence of complication during the early postoperative period between the two groups.

CONCLUSIONS

The introduction of thromboelastometry (ROTEM) measurements in hemostatic therapy algorithms reduces the transfusion rate of FFP and PRBCs during liver transplantation. The using of ROTEM derived thresholds leads to detecting higher requirements of fibrinogen compared to conventional laboratory tests.

Evidence for a rebalanced hemostatic system in pediatric liver transplantation: A prospective cohort study

In adults with end-stage liver disease concurrent changes in pro- and antihemostatic pathways result in a rebalanced hemostasis. Children though, have a developing hemostatic system, different disease etiologies, and increased risk of thrombosis. This study aimed to assess the hemostatic state of children during and after liver transplantation. Serial blood samples were obtained from 20 children (≤16 years) undergoing primary liver transplantation (September 2017-October 2018). Routine hemostasis tests, thrombomodulin-modified thrombin generation, clot lysis times, and hemostatic proteins were measured. Reference values were established using an age-matched control group of 30 children. Thrombocytopenia was present in study patients. Von Willebrand factors were doubled and ADAMTS13 levels decreased during and after transplantation up until day 30, when platelet count had normalized. Whereas prothrombin time and activated partial thromboplastin time were prolonged during transplantation, thrombin generation was within normal ranges, except during perioperative heparin administration. Fibrinogen, factor VIII levels, and clot lysis time were elevated up until day 30. In conclusion, children with end-stage liver disease are in tight hemostatic balance. During transplantation a temporary heparin-dependent hypocoagulable state is present, which rapidly converts to a hemostatic balance with distinct hypercoagulable features that persist until at least day 30. This hypercoagulable state may contribute to the risk of posttransplant thrombosis.

Coagulation abnormalities, bleeding, thrombosis, and management of patients with acute liver failure in Australia and New Zealand

BACKGROUND AND AIM

To study the management of coagulation and hematological derangements among severe acute liver failure (ALF) patients in Australia and New Zealand liver transplant intensive care units (ICUs).

METHODS

Analysis of key baseline characteristics, etiology, coagulation and hematological tests, use of blood products, thrombotic complications, and clinical outcomes during the first ICU week.

RESULTS

We studied 62 ALF patients. The first day median peak international normalized ratio was 5.5 (inter-quartile range [IQR] 3.8-8.7), median longest activated partial thromboplastin time was 62 s (IQR 44-87), and median lowest fibrinogen was 1.1 (IQR 0.8-1.6) g/L. Fibrinogen was only measured in 85% of patients, which was less than other tests (P < 0.0001). Median initial lowest platelet count was 83 (IQR 41-122) × 10⁹ /L. Overall, 58% of patients received fresh frozen plasma, 40% cryoprecipitate, 35% platelets, and 15% prothrombin complex concentrate. Patients with bleeding complications (19%) had more severe overall hypofibrinogenemia and thrombocytopenia. Thrombotic complications were less common (10% of patients), were not associated with consistent patterns of abnormal hemostasis, and were not immediately preceded by clotting factor administration and half occurred only after liver transplantation surgery.

CONCLUSION

In ALF patients admitted to dedicated Australia and New Zealand ICUs, fibrinogen was measured less frequently than other coagulation parameters but, together with platelets, appeared more relevant to bleeding risk. Blood products and procoagulant factors were administered to most patients at variable levels of hemostatic derangement, and bleeding complications were more common than thrombotic complications. This epidemiologic information and practice variability provide baseline data for the design and powering of interventional studies.

Viscoelastic test-based bleeding risk score reliably predicts coagulopathic bleeding in decompensated cirrhosis and ACLF patients

BACKGROUND AND AIMS

Coagulopathic bleeding risk prediction is challenging in decompensated cirrhosis (DC) by conventional assays. Viscoelastic tests (VETs) are likely to be more useful for assessing coagulation status in these patients. We investigated whether the VET (Sonoclot) parameters with fibrinogen could predict coagulopathic bleeding in these patients.

PATIENTS AND METHODS

Coagulation parameters studied in 874 patients [124 compensated cirrhosis (CC), 521 DC, and 229 acute-on-chronic liver failure (ACLF)] and 190 controls. DC patients were enrolled in derivation (n = 266) and validation (n =  255) cohorts. Sonoclot variables [activated clotting time (ACT), clot rate (CR), platelet function (PF), time to peak (TP) and peak amplitude (PA)] and fibrinogen levels were measured. Coagulopathic bleeding was recorded along with 1-year survival.

RESULTS

DC patients had prolonged ACT (p < 0.001), depressed CR (p = 0.059), reduced PF (p = 0.09), longer TP (p < 0.001) and smaller PA (p < 0.001), compared to CC and controls (p < 0.001 each). In derivation cohort, 32.3% patients had coagulopathic bleeding. Cox regression analysis of derivation cohort revealed; ACT > 190 s, PF < 1.25 and fibrinogen < 1.2 g/l could predict coagulopathic bleeding and were used to develop a bleeding risk score. In validation cohort; this score was comparable, correlated to real events, and had similar bleed free events with time. The score was also useful in predicting bleed in ACLF patients. In DC patients, 1-year mortality was higher those who bled and received transfusions.

CONCLUSION

Viscoelasticity-based bleeding risk score using ACT, PF and fibrinogen, predicts coagulopathic bleeding in DC patients and should be useful in rationalizing transfusion of blood products. We designed a viscoelastic test-based bleeding risk score which is useful in advanced liver disease to predict the coagulation-related bleeding. This figure shows the lower bleeding-free events in advanced cirrhosis with each incremental bleeding risk score.

Whole blood thrombin generation profiles of patients with cirrhosis explored with a near patient assay

BACKGROUND AND AIMS

Patients with cirrhosis have a rebalanced hemostasis, often with normal or elevated thrombin-generating (TG) capacity in plasma. Whole blood (WB) TG allows faster determination and, importantly, includes the influence of all circulating blood cells. We aimed to study the TG profile of patients with cirrhosis in WB and in platelet poor plasma.

METHODS

Thrombin-generating capacity in WB and plasma were assessed with a near-patient WB-TG assay and the calibrated automated thrombinography assay, respectively. TG assays were tested in presence and absence of thrombomodulin. Conventional coagulation tests were also performed.

RESULTS

Thirty-four patients with cirrhosis and twenty-two controls were analyzed. Compared with controls, patients had substantially deranged results in conventional coagulation tests. Comparable WB-TG capacity (endogenous thrombin potential until peak, ETPp) but significantly lower peak thrombin were found in patients, and these results persisted when thrombomodulin was present. TG of the patients was more resistant to thrombomodulin than controls in both WB and plasma, although the inhibitory effect of thrombomodulin was drastically weaker in WB than in plasma. The peak of WB-TG in patients correlated moderately with their hematocrit and platelet count. Significant correlations were found between TG results in WB and plasma.

CONCLUSIONS

The WB-TG assay shows a normal to hypocoagulable state in patients with cirrhosis with a decreased anticoagulant activity of TM compared to plasma-TG. The clinical value of this assay needs further validation.