Incidence of Bleeding and Thrombosis in Patients with Liver Disease

An Approach to Investigations of Chronic Liver Disease

Chronic liver disease (CLD) in children is more diverse compared to adults with respect to the etiology, progression and response to therapy. After history and clinical examination, the first step is to confirm the presence of CLD with basic blood investigations and ultrasonography. Markers of portal hypertension are splenomegaly, increased portal vein diameter, thrombocytopenia and presence of varices on endoscopy. The next step is to evaluate the etiology of CLD which will depend on the age of the child and needs targeted investigations as metabolic and inherited causes predominate in early childhood. CLD progression ought to be monitored regularly and several non-invasive markers are available but they have to be evaluated further in children. Since CLD progresses, complications have to be detected early not only to initiate appropriate treatment but also to prognosticate.

Intensive care management of acute-on-chronic liver failure

Acute-on-chronic liver failure (ACLF) is a clinical syndrome defined by an acute deterioration of the liver function associated with extrahepatic organ failures requiring intensive care support and associated with a high short-term mortality. ACLF has emerged as a major cause of mortality in patients with cirrhosis and chronic liver disease. ACLF has a unique pathophysiology in which systemic inflammation plays a key role; this provides the basis of novel therapies, several of which are now in clinical trials. Intensive care unit (ICU) therapy parallels that applied in the general ICU population in some organ failures but has peculiar differential characteristics in others. Critical care management strategies and the option of liver transplantation (LT) should be balanced with futility considerations in those with a poor prognosis. Nowadays, LT is the only life-saving treatment that can radically improve the long-term prognosis of patients with ACLF. This narrative review will provide insights on the current understanding of ACLF with emphasis on intensive care management.

Acute-on-chronic liver failure: Controversies and consensus

Acute-on-chronic liver failure (ACLF) is a poorly defined syndrome characterised by rapid clinical deterioration in patients with chronic liver disease. Consequences include high short-term morbidity, mortality, and healthcare resource utilisation. ACLF encompasses a dysregulated, systemic inflammatory response, which can precipitate extra hepatic organ failures. Common precipitants include infection, alcoholic hepatitis, and reactivation of viral hepatitis although frequently no cause is identified. Heterogenous definitions, diagnostic criteria, and treatment guidelines, have been proposed by international hepatology societies. This can result in delayed or missed diagnoses of ACLF, significant variability in clinical management, and under-estimation of disease burden. Liver transplantation may be considered but the mainstay of treatment is organ support, often in the intensive care unit. This review will provide clarity around where are the controversies and consensus in ACLF including: Epidemiology and resource utilisation, key clinical and diagnostic features, strategies for management, and research gaps.

Fibrin clot quality in acutely ill cirrhosis patients: Relation with outcome and improvement with coagulation factor concentrates

BACKGROUND & AIMS

Patients with liver disease may acquire substantial changes in their hemostatic system, which are most pronounced in patients who are critically ill. Changes in the quality of the fibrin clot in critically ill patients have not been studied in detail. Here we assessed markers of fibrin clot quality and effects of coagulation factor concentrates in patients with acutely decompensated (AD) cirrhosis and acute on chronic liver failure (ACLF).

METHODS

We measured plasma levels of fibrinogen, factor XIII, prothrombin and performed thrombin generation assays in 52 AD patients, 58 ACLF patients and 40 controls. In addition, we examined the effects of coagulation factor concentrates on functional assays of fibrin quality.

RESULTS

We found increased thrombin generating capacity in both AD and ACLF in comparison with healthy controls. Plasma levels of prothrombin, fibrinogen, and factor XIII were lower in patients compared to controls, appeared lower in ACLF compared to AD patients, and were related to clinical outcomes. Fibrinogen concentrate, but not factor XIII or prothrombin complex concentrate, improved clot quality in vitro. Prothrombin complex concentrate increased the resistance of the clot to break down.

CONCLUSIONS

We have demonstrated elevated thrombin generation but decreased plasma levels of prothrombin, fibrinogen and FXIII in acutely ill patients with cirrhosis. In addition, we showed that fibrinogen concentrate and PCCs, but not factor XIII concentrate, improve clot properties in patient plasma. Whether there is true clinical benefit from coagulation factor concentrates in prevention or treatment of bleeding requires further study.

LAY SUMMARY

Patients with liver diseases are at risk of bleeding, but mechanisms involved in this bleeding risk are incompletely understood. We studied components that determine the stability of the blood clot and found that concentrations of certain proteins involved in clot stability are present in low levels in acutely ill patients with liver disease. We furthermore demonstrated that some clinically available drugs improve the stability of blood clots from these patients in a test tube.

Atypical Roles of the Chemokine Receptor ACKR3/CXCR7 in Platelet Pathophysiology

The manifold actions of the pro-inflammatory and regenerative chemokine CXCL12/SDF-1α are executed through the canonical GProteinCoupledReceptor CXCR4, and the non-canonical ACKR3/CXCR7. Platelets express CXCR4, ACKR3/CXCR7, and are a vital source of CXCL12/SDF-1α themselves. In recent years, a regulatory impact of the CXCL12-CXCR4-CXCR7 axis on platelet biogenesis, i.e., megakaryopoiesis, thrombotic and thrombo-inflammatory actions have been revealed through experimental and clinical studies. Platelet surface expression of ACKR3/CXCR7 is significantly enhanced following myocardial infarction (MI) in acute coronary syndrome (ACS) patients, and is also associated with improved functional recovery and prognosis. The therapeutic implications of ACKR3/CXCR7 in myocardial regeneration and improved recovery following an ischemic episode, are well documented. Cardiomyocytes, cardiac-fibroblasts, endothelial lining of the blood vessels perfusing the heart, besides infiltrating platelets and monocytes, all express ACKR3/CXCR7. This review recapitulates ligand induced differential trafficking of platelet CXCR4-ACKR3/CXCR7 affecting their surface availability, and in regulating thrombo-inflammatory platelet functions and survival through CXCR4 or ACKR3/CXCR7. It emphasizes the pro-thrombotic influence of CXCL12/SDF-1α exerted through CXCR4, as opposed to the anti-thrombotic impact of ACKR3/CXCR7. Offering an innovative translational perspective, this review also discusses the advantages and challenges of utilizing ACKR3/CXCR7 as a potential anti-thrombotic strategy in platelet-associated cardiovascular disorders, particularly in coronary artery disease (CAD) patients post-MI.

Periprocedural management of abnormal coagulation parameters and thrombocytopenia in patients with cirrhosis: Guidance from the SSC of the ISTH

Prolonged prothrombin time and thrombocytopenia are common in patients with cirrhosis. These parameters do not reflect the overall hemostatic rebalance or bleeding risk in the periprocedural setting; however, attempts to correct these parameters remain frequent. We review the literature on periprocedural bleeding risk, bleeding risk factors, and the risk and benefits of hemostatic interventions in patients with cirrhosis. We provide guidance recommendations on evaluating bleeding risk in this patient group and management of hemostatic abnormalities in the periprocedural setting.

Rebalanced hemostasis in liver disease: a misunderstood coagulopathy

The combination of frequently abnormal hemostatic markers and catastrophic bleeding as seen with variceal hemorrhage has contributed to the longstanding misperception that chronic liver disease (CLD) constitutes a bleeding diathesis. Laboratory studies of hemostasis in liver disease consistently challenge this with global coagulation assays incorporating activation of the protein C pathway demonstrating rebalanced hemostasis. It is now recognized that bleeding in CLD is predominantly secondary to portal hypertension (rather than a coagulopathy) and additionally that these patients are at increased risk of venous thrombosis, particularly in the portal venous system. This narrative review describes the current understanding of hemostasis in liver disease, as well as the periprocedural management of hemostasis and anticoagulation for management of venous thromboembolism in patients with CLD.

Hemostasis testing in patients with liver dysfunction: Advantages and caveats

Due to concomitant changes in pro- and anti-coagulant mechanisms, patients with liver dysfunction have a “rebalanced hemostasis”, which can easily be tipped toward either a hypo- or a hypercoagulable phenotype. Clinicians are often faced with the question whether patients with chronic liver disease undergoing invasive procedures or surgery and those having active bleeding require correction of the hemostasis abnormalities. Conventional coagulation screening tests, such as the prothrombin time/international normalized ratio and the activated partial thromboplastin time have been demonstrated to have numerous limitations in these patients and do not predict the risk of bleeding prior to high-risk procedures. The introduction of global coagulation assays, such as viscoelastic testing (VET), has been an important step forward in the assessment of the overall hemostasis profile. A growing body of evidence now suggests that the use of VET might be of significant clinical utility to prevent unnecessary infusion of blood products and to improve outcomes in numerous settings. The present review discusses the advantages and caveats of both conventional and global coagulation assays to assess the risk of bleeding in patients with chronic liver disease as well as the current role of transfusion and hemostatic agents to prevent or manage bleeding.

Prevalence of bleeding and thrombosis in critically ill patients with chronic liver disease

INTRODUCTION

Haemorrhage and venous thromboembolism (VTE) are recognised complications of chronic liver disease (CLD), but their prevalence and risk factors in critically ill patients is uncertain.

PATIENTS AND METHODS

We studied a retrospective cohort of patients with CLD non-electively admitted to a specialist intensive care unit determining the prevalence and timing of major bleeding and VTE (early, present on admission/diagnosed within 48h; later diagnosed >48h post ICU admission). Associations with baseline clinical and laboratory characteristics, multi-organ failure (MOF), blood product administration and mortality were explored. Odds ratios (OR) and 95% CIs were calculated using logistic regression.

RESULTS

Of 623 patients with median age 52, bleeding (>48 hours after admission) occurred in 87 (14%) patients. Bleeding was associated with greater illness severity and increased mortality. Gastrointestinal bleeding accounted for 72% of events, secondary to portal hypertension in >90%. Procedure-related bleeding was uncommon. VTE occurred in 125 (20%) patients: Early VTE in 80 (13%) and involving the portal vein (PVT) in 85%. Later VTE affected 45 (7.2%) patients. Hepatocellular Carcinoma (HCC) and non-alcoholic liver disease were independently associated with early VTE (OR 2.79, (95% CI 1.5 -5.2) and 2.32, (1.4 -3.9) respectively), and HCC, sepsis and cryoprecipitate use with late VTE (OR 2.45, (1.11-5.43), 2.26 (1.2-4.3) and 2.60 (1.3-5.1).

CONCLUSION

VTE was prevalent on admission to critical care and less commonly developed later. Bleeding was associated with MOF and increased mortality. Severe MOF was not associated with an increased rate of VTE which was linked with HCC, and specific etiologies of CLD.

Treatment of bleeding in patients with liver disease

Patients with cirrhosis frequently have complex alterations in their hemostatic system. Although routine diagnostic tests of hemostasis in cirrhosis (platelet count, prothrombin time, fibrinogen level) are suggestive of a bleeding tendency, it is now widely accepted that these tests do not reflect hemostatic competence in this population. Rather, patients with cirrhosis appear to have a rebalanced hemostatic system with hypercoagulable elements. Therefore, routine correction of hemostasis laboratory values, for example by fresh frozen plasma or platelet concentrates, with the aim to avoid spontaneous or procedure-related bleeding is not indicated as is outlined in recent clinical guidance documents. However, little guidance on how to manage patients with cirrhosis that are actively bleeding is available. Here we present three common bleeding scenarios, variceal bleeding, post-procedural bleeding and bleeding in a critically ill cirrhosis patient, with specific management suggestions. As patients with cirrhosis generally have adequate hemostatic competence and as bleeding complications may be unrelated to hemostatic failure, prohemostatic therapy is not the first line of management in bleeding patients with cirrhosis, even in the presence of markedly abnormal platelet counts and/or prothrombin times. We provide a rationale for the restrictive approach to prohemostatic therapy in bleeding patients with cirrhosis.

Heparins have adequate ex vivo anticoagulant effects in hospitalized patients with cirrhosis

BACKGROUND

Patients with cirrhosis are at risk of venous thromboembolism (VTE), but strategies for thromboprophylaxis have not been defined. Previous in vitro studies suggest an altered anticoagulant effect of heparins in patients with cirrhosis.

OBJECTIVES

To assess the anticoagulant effects of prophylactic low-molecular-weight heparin (LMWH) or unfractionated heparin (UFH) doses in patients with cirrhosis in a real-life clinical setting.

METHODS

We studied patients with cirrhosis (n = 16) and acute-on-chronic liver failure (ACLF) (n = 14), and compared these with patients without underlying liver disease admitted to non-liver general medical wards (n = 18) and non-liver intensive care units (n = 14), respectively. Blood samples were taken before and 4 h after administration of the first dose of LMWH or UFH. We assessed hemostatic status using thrombin generation assays, thrombin-antithrombin complexes (TAT), and conventional coagulation assays, and included healthy controls (n = 20) to establish reference values. Anti-Xa activity was determined to estimate peak heparin levels.

RESULTS

Baseline thrombin generation was similar among all cohorts and healthy controls despite alterations in conventional coagulation assays. On heparin, both absolute and proportional changes of thrombin generation were comparable between all four cohorts (-62% to -85%). TAT levels decreased in all cohorts apart from the ACLF cohort, but did not correlate with the proportional change in thrombin generation. Anti-Xa activity correlated with the proportional change in thrombin generation in patients receiving LMWH, but not in patients receiving UFH.

CONCLUSIONS

These data suggest that current prophylactic heparin doses have comparable anticoagulant effects in patients with cirrhosis compared with patients without underlying liver disease.

Till Death Do Us Part-The Multifaceted Role of Platelets in Liver Diseases

Platelets are tightly connected with the liver, as both their production and their clearance are mediated by the liver. Platelets, in return, participate in a variety of liver diseases, ranging from non-alcoholic fatty liver diseases, (viral) hepatitis, liver fibrosis and hepatocellular carcinoma to liver regeneration. Due to their versatile functions, which include (1) regulation of hemostasis, (2) fine-tuning of immune responses and (3) release of growth factors and cellular mediators, platelets quickly adapt to environmental changes and modulate disease development, leading to different layers of complexity. Depending on the (patho)physiological context, platelets exert both beneficial and detrimental functions. Understanding the precise mechanisms through which platelet function is regulated at different stages of liver diseases and how platelets interact with various resident and non-resident liver cells helps to draw a clear picture of platelet-related therapeutic interventions. Therefore, this review summarizes the current knowledge on platelets in acute and chronic liver diseases and aims to shed light on how the smallest cells in the circulatory system account for changes in the (patho)physiology of the second largest organ in the human body.