Deficiency of thrombin activatable fibrinolysis inhibitor in cirrhosis is associated with increased plasma fibrinolysis

Reappraisal of the conventional hemostasis tests as predictors of perioperative bleeding in the era of rebalanced hemostasis in cirrhosis

New global laboratory procedures mimicking the in vivo hemostasis process led to the changing paradigm of cirrhosis from the prototype of hemorrhagic diseases to a condition in which hemostasis is normal but fragile, thus justifying the hemorrhagic/thrombotic tendencies that affect these patients. The new paradigm was instrumental to change the management of cirrhosis. For example, international guidelines warn against the entrenched practice of testing patients with conventional hemostasis tests and infusing those with abnormalities with fresh-frozen plasma, coagulation factor concentrates, or platelets, prior to surgery/invasive procedures. These recommendations are, however, largely disattended. The practice of testing patients with the prothrombin time or viscoelastometry and using arbitrary cutoffs to make decisions on perioperative prophylaxis is still common and probably driven by medicolegal issues. There is no doubt that prothrombin time and congeners tests are unable to predict bleeding in cirrhosis. However, it cannot be excluded that some tests may be useful in patients who are severely decompensated. Large prospective collaborative studies are warranted. Enrolled patients should be randomized to receive perioperative prophylaxis based on laboratory testing (eg, viscoelastometry, thrombomodulin-modified thrombin generation) or to usual care. However, for these trials to be useful, a third group of patients who do not receive prophylaxis should be included. In conclusion, until results from these studies are available, physicians attending cirrhosis should refrain from using laboratory tests with arbitrary cutoffs to make decision on perioperative prophylaxis. Decision should be made by considering the clinical history of individual patients and the risk of hemorrhage of specific procedures.

Spontaneous muscle haematoma in a patient with cirrhosis

Decompensated liver disease is associated with alterated haemostasis that can either lead to spontaneous bleeding or development of thrombosis. Alcohol consumption coupled with advanced liver disease favours spontaneous bleeding. There have been only few documented cases of spontaneous muscle haematoma (SMH) in patients with cirrhosis. The pathogenesis of SMH is hypothesised to be multifactorial and it has been seen in patients on anticoagulation or with haemostatic disorders. We report a case of alcohol-related cirrhosis presenting with an expanding, voluminous haematoma in the intermuscular plane between the trapezius and the teres major muscles. This patient also had a retroperitoneal haemorrhage, clinically evidenced by the Grey Turner's and Cullen's signs. Haemorrhage was confirmed radiologically by CT. The patient was managed in an intensive care facility and treated with multiple blood products, including packed red blood cells, fresh frozen plasma and cryoprecipitates. However, as his clinical condition deteriorated, he required surgical intervention by incision and drainage, followed by evacuation. Early identification of coagulopathy and aggressive treatment are essential in these cases of cirrhosis to avoid unfavourable outcomes.

Vascular complications after liver transplantation: contemporary approaches to detection and treatment. A literature review

Vascular complications (VCs) after liver transplantation (LT) are rare but are one of the most dreaded conditions that can potentially lead to graft loss and recipient death. This paper has analyzed the international experience in the early diagnosis of various VCs that can develop following LT, as well as the optimal timing and methods of treatment of these complications.

Management of the acute on chronic liver failure in the intensive care unit

Acute on chronic liver failure (ACLF) reflects the development of organ failure(s) in a patient with cirrhosis and is associated with high short-term mortality. Given that ACLF has many different 'phenotypes', medical management needs to take into account the relationship between precipitating insult, organ systems involved and underlying physiology of chronic liver disease/cirrhosis. The goals of intensive care management of patients suffering ACLF are to rapidly recognize and treat inciting events (e.g. infection, severe alcoholic hepatitis and bleeding) and to aggressively support failing organ systems to ensure that patients may successfully undergo liver transplantation or recovery. Management of these patients is complex since they are prone to develop new organ failures and infectious or bleeding complications. ICU therapy parallels that applied in the general ICU population in some complications but differs in others. Given that liver transplantation in ACLF is an emerging and evolving field, multidisciplinary teams with expertise in critical care and transplant medicine best accomplish management of the critically ill ACLF patient. The focus of this review is to identify the common complications of ACLF and to describe the proper management in critically ill patients awaiting liver transplantation in our centres, including organ support, prognostic assessment and how to assess when recovery is unlikely.

Patient Blood Management in Liver Transplant—A Concise Review

Transfusion of blood products in orthotopic liver transplantation (OLT) significantly increases post-transplant morbidity and mortality and is associated with reduced graft survival. Based on these results, an active effort to prevent and minimize blood transfusion is required. Patient blood management is a revolutionary approach defined as a patient-centered, systematic, evidence-based approach to improve patient outcomes by managing and preserving a patient’s own blood while promoting patient safety and empowerment. This approach is based on three pillars of treatment: (1) detecting and correcting anemia and thrombocytopenia, (2) minimizing iatrogenic blood loss, detecting, and correcting coagulopathy, and (3) harnessing and increasing anemia tolerance. This review emphasizes the importance of the three-pillar nine-field matrix of patient blood management to improve patient outcomes in liver transplant recipients.

Fibrin clot properties and thrombus composition in cirrhosis

Patients with cirrhosis frequently acquire profound hemostatic alterations, which may affect thrombus quality and composition-factors that determine the susceptibility to embolization and fibrinolysis. In this narrative review, we describe in vitro studies on fibrin clot formation and quantitative and qualitative changes in fibrinogen in patients with cirrhosis, and describe recent findings on the composition of portal vein thrombi in patients with cirrhosis. Patients with mild cirrhosis have increased thrombin generation capacity and plasma fibrinogen levels, which may be balanced by delayed fibrin polymerization and decreased factor XIII levels. With progressing illness, plasma fibrinogen levels decrease, but thrombin generation capacity remains elevated. Fibrinogen is susceptible to posttranslational protein modifications and is, for example, hypersialylated and carbonylated in patients with cirrhosis. Despite changes in thrombin generation, factor XIII levels and the fibrinogen molecule, fibrin fiber thickness, and density are normal in patients with cirrhosis. Paradoxically, fibrin clot permeability in patients with cirrhosis is decreased, possibly because of posttranslational protein modifications. Most patients have normal fibrinolytic potential. We have recently demonstrated that portal vein thrombosis is likely a misnomer as the material that may obstruct the cirrhotic portal vein frequently consists of a thickened portal vein wall, rather than a true thrombus. Patients with cirrhosis often have thrombocytopenia and anemia, which may also affect clot stability and composition, but the role of cellular components in clot quality in cirrhosis has not been extensively studied. Finally, we summarize abstracts on fibrin formation and clot quality that were presented at the ISTH 2022 meeting in London.

Blood loss during liver transplantation is a predictor of postoperative thrombosis

Liver transplantation (LT) is an effective way to cure end-stage liver diseases (ESLDs), which have generally been regarded as examples of acquired bleeding disorders. However, postoperative thrombosis after LT is recognised and remains a life-threatening complication. This study aimed to show that blood loss during LT is a predictor of postoperative thrombosis and to establish a predictive model. We analysed the medical records of all patients who underwent LT at the First Affiliated Hospital of Xi'an Jiaotong University from January 2017 to April 2019 to identify the risk factors for post-transplant thrombosis. The predictive nomogram was established based on independent predictors identified by logistic regression analysis. Blood loss during LT of ≥31.25 mL/kg can predict postoperative thrombosis, and the nomogram achieved an accurate prediction.

Fibrinogen and Antifibrinolytic Proteins: Interactions and Future Therapeutics

Thrombus formation remains a major cause of morbidity and mortality worldwide. Current antiplatelet and anticoagulant therapies have been effective at reducing vascular events, but at the expense of increased bleeding risk. Targeting proteins that interact with fibrinogen and which are involved in hypofibrinolysis represents a more specific approach for the development of effective and safe therapeutic agents. The antifibrinolytic proteins alpha-2 antiplasmin (α2AP), thrombin activatable fibrinolysis inhibitor (TAFI), complement C3 and plasminogen activator inhibitor-2 (PAI-2), can be incorporated into the fibrin clot by FXIIIa and affect fibrinolysis by different mechanisms. Therefore, these antifibrinolytic proteins are attractive targets for the development of novel therapeutics, both for the modulation of thrombosis risk, but also for potentially improving clot instability in bleeding disorders. This review summarises the main properties of fibrinogen-bound antifibrinolytic proteins, their effect on clot lysis and association with thrombotic or bleeding conditions. The role of these proteins in therapeutic strategies targeting the fibrinolytic system for thrombotic diseases or bleeding disorders is also discussed.

Viscoelastic tests in liver disease: where do we stand now?

Hemostasis is a complex physiological process based on the balance between pro-coagulant and anticoagulant systems to avoid pathological bleeding or thrombosis. The changes in standard coagulation tests in liver disease were assumed to reflect an acquired bleeding disorder, and cirrhotic patients were considered naturally anticoagulated. In the light of the new evidence, the theory of rebalanced hemostasis replaced the old concept. According to this model, the hemostatic alteration leads to a unique balance between pro-coagulant, anticoagulant, and fibrinolytic systems. But the balance is fragile and may prone to bleeding or thrombosis depending on various risk factors. The standard coagulation tests [INR (international normalized ratio), platelet count and fibrinogen] only explore parts of the hemostasis, not offering an entire image of the process. Rotational thromboelastometry (ROTEM) and thromboelastography (TEG) are both point of care viscoelastic tests (VET) that provide real-time and dynamic information about the entire hemostasis process, including clot initiation (thrombin generation), clot kinetics, clot strength, and clot stability (lysis). Despite prolonged PT/INR (international normalized ratio of prothrombin time) and low platelet counts, VET is within the normal range in many patients with both acute and chronic liver disease. However, bleeding remains the dominant clinical issue in patients with liver diseases, especially when invasive interventions are required. VET has been shown to asses more appropriately the risk of bleeding than conventional laboratory tests, leading to decrial use of blood products transfusion. Inappropriate clotting is common but often subtle and may be challenging to predict even with the help of VET. Although VET has shown its benefit, more studies are needed to establish cut-off values for TEG and ROTEM in these populations and standardization of transfusion guidelines before invasive interventions in cirrhotic patients/orthotopic liver transplantation.

Serum and ascitic D-dimer in cirrhotic patients with spontaneous bacterial peritonitis

Aim of the study

The study aimed to investigate serum and ascitic fluid D-dimer level in patients with liver cirrhosis with and without ascites and to evaluate the impact of spontaneous bacterial peritonitis (SBP) on circulating serum and ascitic fluid D-dimer levels.

Material and methods

This study was conducted on 60 subjects who were further subdivided into group I comprising 15 patients with liver cirrhosis and no ascites, group II comprising 15 cirrhotic patients with ascites, group III comprising 15 cirrhotic patients with ascites and SBP, and group IV comprising 15 healthy controls. All patients were subjected to full history taking, physical examination, laboratory investigations, and measurement of serum D-dimer in all groups and ascitic fluid D-dimer in groups II and III. The diagnostic performance of serum D-dimer was tested to detect SBP.

Results

Serum D-dimer differed significantly between groups III and IV, whilst no significant differences were detected between the other groups and group IV. Moreover, group III showed a significantly higher level of serum D-dimer. Ascitic fluid D-dimer mean levels showed no statistically significant differences. A statistically significant positive correlation was found between serum D-dimer level and ascitic fluid D-dimer in group III, r = 0.682. Using a sensitivity and specificity level of 80%, a cut-off value (COV) of > 323.2 ng/ml could differentiate between patients with SBP and patients with ascites only.

Conclusions

Serum D-dimer significantly correlated with ascitic fluid D-dimer in patients with SBP, whereas no significant correlation was found in patients with cirrhotic ascites without bacterial infection. D-dimer showed good diagnostic performance for SBP among patients with liver cirrhosis.

Altered Fibrinolysis during and after Surgery

Major surgery induces hemostatic changes related to surgical stress, tissue destruction, and inflammatory reactions. These changes involve a shift of volume from extravascular space to intravascular and interstitial spaces, a "physiologic" hemodilution of coagulation proteins, and an increase of plasmatic fibrinogen concentration and platelets. Increases in fibrinogen and platelets together with a simultaneous dilution of pro- and anticoagulant factors and development of a hypofibrinolytic status result in a postoperative hypercoagulable state. This profile is accentuated in more extensive surgery, but the balance can shift toward hemorrhagic tendency in specific types of surgeries, for example, in prolonged cardiopulmonary bypass or in patients with comorbidities, especially liver diseases, sepsis, and hematological disorders. Also, acquired coagulopathy can develop in patients with trauma, during obstetric complications, and during major surgery as a result of excessive blood loss and subsequent consumption of coagulation factors as well as hemodilution. In addition, an increasing number of patients receive anticoagulants and antiplatelet drugs preoperatively that might influence the response to surgical hemostasis. This review focuses on those situations that may change normal hemostasis and coagulation during surgery, producing both hyperfibrinolysis and hypofibrinolysis, such as overcorrection with coagulation factors, bleeding and hyperfibrinolysis that may occur with extracorporeal circulation and high aortic-portal-vena cava clamps, and hyperfibrinolysis related to severe maintained hemodynamic disturbances. We also evaluate the role of tranexamic acid for prophylaxis and treatment in different surgical settings, and finally the value of point-of-care testing in the operating room is commented with regard to investigation of fibrinolysis.

Fibrinolysis in Patients with Liver Disease

Patients with liver disease acquire complex changes in their hemostatic system. Historically, these patients were considered to have a bleeding tendency related, in part, to a hyperfibrinolytic state. However, studies using more modern fibrinolysis tests have questioned the presence of a hyperfibrinolytic state in patients with liver disease and its association with bleeding risk. It may be that the sickest patients with liver disease do have fibrinolytic abnormalities. However, the debate on the fibrinolytic state of patients with (decompensated) cirrhosis or critically ill liver disease is complicated by the fact that hypo- and hyperfibrinolysis have been poorly defined. This could, in part, be explained by the lack of reliable tests that assess a patient's fibrinolytic status. Moreover, large clinical studies on the relationship between bleeding and fibrinolysis in patients with liver disease are scarce. Here, we provide an overview of the current knowledge on fibrinolysis in various types of liver diseases and possible implications as a target for therapeutic strategies in liver disease. As antifibrinolytic therapy has been shown to be safe and effective during liver transplantation, it could potentially be of use in patients with (either laboratory-established or suspected) hyperfibrinolysis-related bleeding.

Altered clot formation and lysis are associated with increased fibrinolytic activity in ascites in patients with advanced cirrhosis

Analysis of coagulation disorders and assessment of rebalanced hemostasis with the use of traditional coagulation assays is challenging in cirrhotic patients. Therefore, alternative tests are under investigation for the evaluation of coagulopathy in this specific setting. Aim of this study was to analyze the modifications of clot structure and function in cirrhotic patients with different degrees of severity. Cirrhotic patients referred to our Unit were consecutively enrolled. Global test measurements, including clot and lysis assays, clot lysis time, and determination of other fibrinolytic parameters, were performed. Analyses of clot formation, morphology, and lysis were performed with a turbidimetric clotting and lysis assay (EuroCLOT). Lysis of a tissue factor-induced clot by exogenous tissue plasminogen activator was analyzed by studying the modifications of turbidity during clot formation and the following lysis. We evaluated coagulative and fibrinolytic parameters in both plasma and ascites. Urokinase plasminogen activator (uPA) and gelatinase activity in ascites were also measured. We analyzed data from 33 cirrhotic patients (11 in Child-Pugh class A; 22 in class B or C and with ascites) and 21 healthy subjects (HS). In class B/C patients prolonged latency time, a decline in clotting absorbance, and decreased fibrin formation were observed in comparison with class A and HS. Generated curves and Thrombin-Activatable Fibrinolysis Inhibitor (TAFI) progressively declined from HS to class C patients, whereas levels of plasminogen activator inhibitor-1 and tissue plasminogen activator increased. D-dimer levels were markedly increased in ascites, together with significantly smaller levels of TAFI, αlfa2-antiplasmin, and plasminogen. Caseinolytic activity was also present. Class C patients showed smaller amount of uPA and significantly lower levels of matrix metallopeptidases (MMP)2 in ascites in comparison with Class B subjects. Clot formation and lysis are altered in cirrhosis and fibrinolysis is activated in ascites. Ascitic levels of uPA and MMP2 are reduced and inversely related to the severity of liver disease.

ACG Clinical Guideline: Disorders of the Hepatic and Mesenteric Circulation

Disorders of the mesenteric, portal, and hepatic veins and mesenteric and hepatic arteries have important clinical consequences and may lead to acute liver failure, chronic liver disease, noncirrhotic portal hypertension, cirrhosis, and hepatocellular carcinoma. Although literature in the field of vascular liver disorders is scant, these disorders are common in clinical practice, and general practitioners, gastroenterologists, and hepatologists may benefit from expert guidance and recommendations for management of these conditions. These guidelines represent the official practice recommendations of the American College of Gastroenterology. Key concept statements based on author expert opinion and review of literature and specific recommendations based on PICO/GRADE analysis have been developed to aid in the management of vascular liver disorders. These recommendations and guidelines should be tailored to individual patients and circumstances in routine clinical practice.

The optimal use of blood components in the management of gastrointestinal bleeding

Acute gastrointestinal bleeding accounts for 5,000 deaths per annum in the UK and is the second-most common indication for transfusion of blood components. Transfusion of blood components is integral to management of these patients. Recent years have seen an expansion in the evidence base for their use in this population and this review aims to provide up-to-date guidance on the use of red cells, plasma, platelets, sources of concentrated fibrinogen and adjuncts such as antifibrinolytic agents in patients with acute gastrointestinal haemorrhage. Key considerations include whether or not it is appropriate to extrapolate from studies in trauma patients to the GI bleeding population, whether restrictive red cell transfusion is appropriate for all patients and whether the presence or absence of liver disease has implications for our transfusion practice. Clinical evidence now favours restrictive transfusion of red blood cells in the haemodynamically stable bleeding patient, but there remain significant evidence gaps concerning the use of plasma, platelets and adjunctive measures.

Perioperative thromboprophylaxis in liver transplant patients

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

Low Fibrinogen Levels Are Associated with Bleeding After Varices Ligation in Thrombocytopenic Cirrhotic Patients

INTRODUCTION AND AIM

EVBL is a procedure frequently performed in cirrhotic patients for primary prophylaxis of bleeding. Patients with cirrhosis display various degrees of alteration of common coagulation parameters, and it is not known whether these alterations may predict post-EVBL bleeding. To evaluate factors predictive of post-endoscopic variceal band ligation (EVBL) bleeding in cirrhotic patients with thrombocytopenia.

METHODS

We included 109 patients with cirrhosis undergoing EVBL for primary prophylaxis of variceal bleeding. Common coagulation parameters (INR, fibrinogen levels) and complete haemogram were obtained in all patients and evaluated subdividing patients in bleeders and non bleeders following EVBL.

RESULTS

The incidence of post-EVBL bleeding was 5.5% (6 patients). INR and platelet counts, considered as continuous or dichotomous variables according to common cut-offs (i.e., INR>1.5, platelet count <50x109/L) were not predictors of post-EVBL bleeding. Patients who bled had significantly lower fibrinogen levels [146 mg/dL (98 - 262) versus 230 mg/dL (104 - 638), P=0.009], and no other biochemical or clinical predictors of bleeding were identified. A fibrinogen cut-off of 179 mg/dL had 98.6% negative predictive value for bleeding.

CONCLUSION

low fibrinogen levels are associated with an increased risk of bleeding following prophylactic EVBL in cirrhotic patients, and might be used to stratify patients' risk. However, due to their preliminary nature, these findings need to be confirmed in larger populations.

Primary hyperfibrinolysis: Facts and fancies

Fibrinolysis is a complex process that controls both hemostasis and thrombosis. The regulation of the fibrinolytic system is mediated through a wide array of cofactors and inhibitors that maintain the hemostatic balance in a delicate equilibrium. As a consequence, disturbances in the fibrinolysis pathway are associated with various disease states, ranging from thrombotic to hemorrhagic clinical phenotypes. In particular, a number of inherited and acquired disorders are associated with an enhanced fibrinolysis leading to a bleeding tendency that in some cases may be life-threatening. Hyperfibrinolysis has been classified into primary and secondary forms but such differentiation, which may have important treatment implications, is still controversial. This narrative review will be focused on inherited and acquired conditions associated with primary hyperfibrinolysis.

The Coagulation Profile of End-Stage Liver Disease and Considerations for Intraoperative Management

The coagulopathy of end-stage liver disease results from a complex derangement in both anticoagulant and procoagulant processes. With even minor insults, cirrhotic patients experience either inappropriate bleeding or clotting, or even both simultaneously. The various phases of liver transplantation along with fluid and blood product administration may contribute to additional disturbances in coagulation. Thus, anesthetic management of patients undergoing liver transplantation to improve hemostasis and avoid inappropriate thrombosis in the perioperative environment can be challenging. To add to this challenge, traditional laboratory tests of coagulation are difficult to interpret in patients with end-stage liver disease. Viscoelastic coagulation tests such as thromboelastography (Haemonetics Corporation, Braintree, MA) and rotational thromboelastometry (TEM International, Munich, Germany) have helped to reduce transfusion of allogeneic blood products, especially fresh frozen plasma, but have also lead to the increased use of fibrinogen-containing products. In general, advancements in surgical techniques and anesthetic management have led to significant reduction in blood transfusion requirements during liver transplantation. Targeted transfusion protocols and pharmacologic prevention of fibrinolysis may further aid in the management of the complex coagulopathy of end-stage liver disease.

Critical care management of the patient with cirrhosis awaiting liver transplant in the intensive care unit

Patients with cirrhosis who are awaiting liver transplantation (LT) are at high risk for developing critical illnesses. Current liver allocation policies that dictate a "sickest first" approach coupled with a mismatch between need and availability of organs result in longer wait times, and thus, patients are becoming increasingly ill while awaiting organ transplantation. Even patients with well-compensated cirrhosis may suffer acute deterioration; the syndrome of acute-on-chronic liver failure (ACLF) results in multisystem organ dysfunction and a marked increase in associated short-term morbidity and mortality. For patients on transplant waiting lists, the development of multisystem organ failure may eliminate candidacy for transplant by virtue of being "too sick" to safely undergo transplantation surgery. The goals of intensive care management of patients suffering ACLF are to rapidly recognize and treat inciting events (eg, infection and bleeding) and to aggressively support failing organ systems to ensure that patients may successfully undergo LT. Management of the critically ill ACLF patient awaiting transplantation is best accomplished by multidisciplinary teams with expertise in critical care and transplant medicine. Such teams are well suited to address the needs of this unique patient population and to identify patients who may be too ill to proceed to transplantation surgery. The focus of this review is to identify the common complications of ACLF and to describe our approach management in critically ill patients awaiting LT in our centers. Liver Transplantation 23 1465-1476 2017 AASLD.

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

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

Hematological Issues in Liver Disease

Acute and chronic liver failure are associated with numerous alterations in different features of the coagulation system. Consequently, there is widespread confusion regarding the potential for both bleeding and thrombosis in patients with liver disease. The risk of bleeding is related to the hemodynamic changes in portal pressures and venous congestion whereas the thrombotic risk stems from changes in the coagulation system. Antithrombotic prophylaxis and treatment of patients with hemorrhage and thrombosis requires careful assessment, interpretation of laboratory workup, and attention to coexistent morbidities. A framework for the management of these conditions is presented for clinicians.

Thrombin activatable fibrinolysis inhibitor as a bleeding predictor in liver transplantation: a pilot observational study

OBJECTIVE

To correlate the levels of thrombin activatable fibrinolysis inhibitor in the immediate postoperative period and at 24 hours postoperatively with the volume of intraoperative bleeding.

METHODS

Twenty-one patients allocated immediately before (elective or emergency) liver transplantation were analyzed. Blood samples were collected for thrombin activatable fibrinolysis inhibitor analysis at three different time points: immediately before liver transplantation (preoperative thrombin activatable fibrinolysis inhibitor), immediately after the surgical procedure (immediate postoperative thrombin activatable fibrinolysis inhibitor), and 24 hours after surgery (thrombin activatable fibrinolysis inhibitor 24 hours after surgery). The primary outcome of the study was to correlate the preoperative and immediate postoperative levels of thrombin activatable fibrinolysis inhibitor with intraoperative blood loss.

RESULTS

There was a correlation between the preoperative thrombin activatable fibrinolysis inhibitor levels and bleeding volume (ρ = -0.469; p = 0.05) but no correlation between the immediate postoperative thrombin activatable fibrinolysis inhibitor and bleeding volume (ρ = -0.062; p = 0.79). No variable included in the linear regression analysis (prehemoglobin, prefibrinogen and preoperative thrombin activatable fibrinolysis inhibitor) was a bleeding predictor. There was a similar trend in the variation between the levels of thrombin activatable fibrinolysis inhibitor at the three different time points and fibrinogen levels. Patients who died within 6 months (14.3%) showed decreased preoperative and immediate postoperative levels of thrombin activatable fibrinolysis compared with survivors (preoperative: 1.3 ± 0.15 versus 2.55 ± 0.53, p = 0.06; immediate postoperative: 1.2 ± 0.15 versus 2.5 ± 0.42, p = 0.007).

CONCLUSION

There was a moderate correlation between preoperative thrombin activatable fibrinolysis inhibitor and intraoperative bleeding in liver transplantation patients, although the predictive role of this variable independent of other variables remains uncertain. Preoperative and immediate postoperative thrombin activatable fibrinolysis inhibitor levels may have a role in the survival prognosis of this population; however, this possibility requires confirmation in further studies with larger sample sizes.

Changing Concepts of Cirrhotic Coagulopathy

The state of clinical art of the coagulopathy of cirrhosis changed considerably over the last decade. Until 2005, cirrhosis was considered as the epitome of the hemorrhagic coagulopathies and the abnormal hemostasis tests associated with the disease were corrected with infusion of fresh frozen plasma or platelets to minimize the risk of bleeding. Since that time, a great deal of work has been done and there is now a change of paradigm. The prothrombin time once considered as an isolated measure of bleeding risk was rejected, and cirrhosis shifted from a purely hemorrhagic construct to a mixed and thrombosis-prone paradigm. In this article we examine the interesting history of how these conceptual changes came about.

Bleeding related to disturbed fibrinolysis

The components and reactions of the fibrinolysis system are well understood. The pathway has fewer reactants and interactions than coagulation, but the generation of a complete quantitative model is complicated by the need to work at the solid‐liquid interface of fibrin. Diagnostic tools to detect disease states due to malfunctions in the fibrinolysis pathway are also not so well developed as is the case with coagulation. However, there are clearly a number of inherited or acquired pathologies where hyperfibrinolysis is a serious, potentially life‐threatening problem and a number of antifibrinolytc drugs are available to treat hyperfibrinolysis. These topics will be covered in the following review.

Thrombin activation and liver inflammation in advanced hepatitis C virus infection

Hepatitis C virus (HCV) infection is associated with increased thrombotic risk. Several mechanisms are involved including direct endothelial damage by the HCV virus, with activation of tissue factor, altered fibrinolysis and increased platelet aggregation and activation. In advanced stages, chronic HCV infection may evolve to liver cirrhosis, a condition in which alterations in the portal microcirculation may also ultimately lead to thrombin activation, platelet aggregation, and clot formation. Therefore in advanced HCV liver disease there is an increased prevalence of thrombotic phenomena in portal vein radicles. Increased thrombin formation may activate hepatic stellate cells and promote liver fibrosis. In addition, ischemic changes derived from vascular occlusion by microthrombi favor the so called parenchymal extinction, a process that promotes collapse of hepatocytes and the formation of gross fibrous tracts. These reasons may explain why advanced HCV infection may evolve more rapidly to end-stage liver disease than other forms of cirrhosis.

Hemostatic balance in patients with liver cirrhosis: Report of a consensus conference

Patients with cirrhosis present with hemostatic alterations secondary to reduced availability of pro-coagulant and anti-coagulant factors. The net effect of these changes is a rebalanced hemostatic system. The Italian Association of the Study of the Liver (AISF) and the Italian Society of Internal Medicine (SIMI) promoted a consensus conference on the hemostatic balance in patients with cirrhosis. The consensus process started with the review of the literature by a scientific board of experts and ended with a formal consensus meeting in Rome in December 2014. The statements were graded according to quality of evidence and strength of recommendations, and approved by an independent jury. The statements presented here highlight strengths and weaknesses of current laboratory tests to assess bleeding and thrombotic risk in cirrhotic patients, the pathophysiology of hemostatic perturbations in this condition, and outline the optimal management of bleeding and thrombosis in patients with liver cirrhosis.

Hemostasis abnormalities in cirrhosis

PURPOSE OF REVIEW

The long-lasting paradigm of cirrhosis as the epitome of the acquired hemorrhagic coagulopathies has been challenged by evidence from the literature. This article reviews the mechanisms responsible for regulation of hemostasis in the light of the evidence provided within the last few years.

RECENT FINDINGS

Numerous studies have evaluated the mechanisms responsible for regulation of primary hemostasis, coagulation and fibrinolysis which were thought to be severely impaired in cirrhosis and were considered responsible for the abnormalities of the prothrombin time and the bleeding events observed in these patients. These evaluations have been performed by newer laboratory tests under experimental conditions that mimic closely the condition operating in vivo.

SUMMARY

Cirrhosis presents with thrombocytopenia and decreased levels of both pro- and anticoagulants. Notable exceptions are factor VIII and von Willebrand factor (VWF) which are increased. Thrombocytopenia (unless very severe) is no longer considered a bleeding risk as platelets from cirrhosis display normal adhesiveness in a flowing system that is mainly supported by the increased levels of VWF. Patients with cirrhosis generate normal amounts of thrombin that is mainly supported by the concomitant deficiency of pro- and anticoagulants that restores the balance between these two opposing drivers.

Thrombin-activatable Fibrinolysis Inhibitor (TAFI) as a Novel Prognostic Factor After Orthotropic Liver Transplantation: A Pilot Study

BACKGROUND

Thrombin-activatable fibrinolysis inhibitor (TAFI), a liver-produced coagulation factor, has been associated with higher mortality in cirrhotic patients, but there has not been any description of its role in perioperative care in liver transplantation cases.

METHODS

A total of 21 patients were included. Serum TAFI levels were determined at 3 time points: preoperatively (TAFI pre), immediately postoperative (TAFI PO), and 24 hours postoperatively (TAFI 24 h). The main outcome was the physiological pattern of TAFI in the perioperative period of liver transplantation. The secondary outcomes were the association between TAFI and early allograft dysfunction (EAD) as well as that of TAFI and 6-month mortality.

RESULTS

TAFI levels increased at the 24-hour time point, compared to the other 2 time points (TAFI pre, P = .007; TAFI PO, P = .0001). Early allograft dysfunction occurred in 2 of 21 patients, both demonstrating lower TAFI 24 h levels compared to those who did not develop this complication (3.0 ± 0.2 vs 1.5 ± 0.3; P = .0001). Three patients who died all demonstrated lower levels of TAFI pre (1.3 ± 0.1 vs 2.5 ± 0.5; P = .001) and TAFI PO (1.2 ± 0.1 vs 2.4 ± 0.4; P = .001) compared to the survivors.

CONCLUSIONS

These findings suggest that the determination of TAFI levels-both pre- and postoperatively-may be of clinical relevance in liver transplant recipients.

Risk of Bleeding in End-Stage Liver Disease Patients Undergoing Cardiac Catheterization

Patients with end-stage liver disease frequently have baseline coagulopathies. The international normalized ratio is in common use for the estimation of bleeding tendency in such patients, especially those undergoing an invasive procedure like cardiac catheterization. The practice of international normalized ratio measurement-followed by pharmacologic (for example, vitamin K or fresh frozen plasma) or nonpharmacologic intervention-is still debatable. The results of multiple randomized trials have shown the superiority of the radial approach over femoral access in reducing catheterization bleeding. This reduction in bleeding in turn decreases the risk and cost of blood-product transfusion. However, there is little evidence regarding the use of the radial approach in the end-stage liver disease patient population specifically. In this review, we summarize the studies that have dealt with cardiac catheterization in patients who have end-stage liver disease. We also discuss the role of the current measurements that are used to reduce the risk of bleeding in these same patients.

Spontaneous bleeding or thrombosis in cirrhosis: What should be feared the most?

The more modern and accurate concept of a rebalanced hemostatic status in cirrhosis is slowly replacing the traditional belief of patients with cirrhosis being “auto-anticoagulated”, prone only to bleeding complications, and protected from thrombotic events. With greater attention to clinical thrombotic events, their impact on the natural history of cirrhosis, and with the emergence and increased use of point-of-care and global assays, it is now understood that cirrhosis results in profound hemostatic alterations that can lead to thrombosis as well as to bleeding complications. Although many clinical decisions are still based on traditional coagulation parameters such as prothrombin (PT), PT, and international normalized ratio, it is increasingly recognized that these tests do not adequately predict the risk of bleeding, nor they should guide pre-emptive interventions. Moreover, altered coagulation tests should not be considered as a contraindication to the use of anticoagulation, although this therapeutic or prophylactic approach is not at present routinely undertaken. Gastroesophageal variceal bleeding continues to be one of the most feared and deadly complications of cirrhosis and portal hypertension, but great progresses have been made in prevention and treatment strategies. Other bleeding sites that are frequently part of end-stage liver disease are similar to clinical manifestations of thrombocytopenia, with gum bleeding and epistaxis being very common but fortunately only rarely a cause of life-threatening bleeding. On the contrary, manifestations of coagulation factor deficiencies like soft tissue bleeding and hemartrosis are rare in patients with cirrhosis. As far as thrombotic complications are concerned, portal vein thrombosis is the most common event in patients with cirrhosis, but venous thromboembolism is not infrequent, and results in important morbidity and mortality in patients with cirrhosis, especially those with decompensated disease. Future studies and the more widespread use of point-of-care tests in evaluating hemostasis will aid the clinician in decision making when facing the patient with bleeding or with thrombotic complications, with both ends of a continuum being potentially fatal.

Antifibrinolytic amino acids for upper gastrointestinal bleeding in people with acute or chronic liver disease

BACKGROUND

Upper gastrointestinal bleeding is one of the most frequent causes of morbidity and mortality in the course of liver cirrhosis. People with liver disease frequently have haemostatic abnormalities such as hyperfibrinolysis. Therefore, antifibrinolytic amino acids have been proposed to be used as supplementary interventions alongside any of the primary treatments for upper gastrointestinal bleeding in people with liver diseases. This is an update of this Cochrane review.

OBJECTIVES

To assess the beneficial and harmful effects of antifibrinolytic amino acids for upper gastrointestinal bleeding in people with acute or chronic liver disease.

SEARCH METHODS

We searched The Cochrane Hepato-Biliary Controlled Trials Register (February 2015), Cochrane Central Register of Controlled Trials (CENTRAL) (Issue 2 of 12, 2015), MEDLINE (Ovid SP) (1946 to February 2015), EMBASE (Ovid SP) (1974 to February 2015), Science Citation Index EXPANDED (1900 to February 2015), LILACS (1982 to February 2015), World Health Organization Clinical Trials Search Portal (accessed 26 February 2015), and the metaRegister of Controlled Trials (accessed 26 February 2015). We scrutinised the reference lists of the retrieved publications.

SELECTION CRITERIA

Randomised clinical trials irrespective of blinding, language, or publication status for assessment of benefits and harms. Observational studies for assessment of harms.

DATA COLLECTION AND ANALYSIS

We planned to summarise data from randomised clinical trials using standard Cochrane methodologies and assessed according to the GRADE approach.

MAIN RESULTS

We found no randomised clinical trials assessing antifibrinolytic amino acids for treating upper gastrointestinal bleeding in people with acute or chronic liver disease. We did not identify quasi-randomised, historically controlled, or observational studies in which we could assess harms.

AUTHORS' CONCLUSIONS

This updated Cochrane review identified no randomised clinical trials assessing the benefits and harms of antifibrinolytic amino acids for upper gastrointestinal bleeding in people with acute or chronic liver disease. The benefits and harms of antifibrinolytic amino acids need to be tested in randomised clinical trials. Unless randomised clinical trials are conducted to assess the trade-off between benefits and harms, we cannot recommend or refute antifibrinolytic amino acids for upper gastrointestinal bleeding in people with acute or chronic liver diseases.

Portal vein thrombosis

Portal vein thrombosis (PVT) is a rare event in the general medical setting that commonly complicates cirrhosis with portal hypertension, and can also occur with liver tumors. The diagnosis is often incidental when a thrombus is found in the portal vein on imaging tests. However, PVT may also present with clinical symptoms and can progress to life-threatening complications of ischemic hepatitis, liver failure, and/or small intestinal infarction. This article reviews the pathophysiology of this disorder, with a major focus on PVT in patients with cirrhosis, and presents detailed guidelines on optimal diagnostic and therapeutic strategies.

Management of coagulation abnormalities in liver disease

Liver disease is characterized by changes in all phases of hemostasis. These hemostatic alterations were long considered to predispose patients with liver disease towards a bleeding tendency, as they are associated with prolonged conventional coagulation tests. However, these patients may also suffer from thrombotic complications, and we now know that the hemostatic system in patient with liver disease is, in fact, in a rebalanced state. In this review we discuss the concept of rebalanced hemostasis and its implications for clinical management of patients with liver disease. For instance, there is no evidence that the use of prophylactic blood product transfusion prior to invasive procedures reduces bleeding risk. Clinicians should also be aware of the possibility of thrombosis occurring in patients with a liver disease, and regular thrombosis prophylaxis should not be withheld in these patients.

Procoagulant therapeutics in liver disease: a critique and clinical rationale

The complex nature of haemostasis in patients with liver disease can result in bleeding and/or thrombosis. These opposing outcomes, which have multiple contributing factors, can pose diagnostic and therapeutic dilemmas for physicians. With the high rate of haemorrhagic complications in patients with cirrhosis, we examine the various procoagulants available for use in this population. In this Review, we describe the clinical and current rationale for using each of the currently available procoagulants-vitamin K, fresh frozen plasma (FFP), cryoprecipitate, platelets, recombinant factor VIIa (rFVIIa), antifibrinolytics, prothrombin concentrate complexes (PCC), desmopressin and red blood cells. By examining the evidence and use of these agents in liver disease, we provide a framework for targeted, goal-directed therapy with procoagulants.

Cirrhosis patients have a coagulopathy that is associated with decreased clot formation capacity

BACKGROUND

The coagulopathy in cirrhosis is associated with thrombosis and bleeding.

OBJECTIVES

To gain better insights into the coagulopathy in patients with cirrhosis, we evaluated plasma thrombin generation and whole blood clot formation in a cross-sectional study.

METHODS

Blood was collected from 73 patients with all-cause cirrhosis (Child-Pugh-A n = 52, B n = 15, C n = 6) and 20 healthy controls. Activity of the coagulation pathways was measured with assays for factor (F) VIIa and FIXa-antithrombin and FXa-antithrombin complexes, respectively. Thrombin generation by calibrated automated thrombography was determined in platelet-poor plasma using a 1 or 5 pm tissue factor trigger with/without thrombomodulin. ROTEM measurements were performed in whole blood triggered with 35 pm tissue factor without/with 175 ng mL(-1) tissue plasminogen activator (the latter refered to as 'tPA-ROTEM').

RESULTS

We observed an increased generation of FVIIa and a moderately elevated amount of FIXa (in complex with antithrombin) without apparent increase in FX activation in patients with cirrhosis. In accordance with this prothrombotic state, markers of thrombin generation potential were also increased upon increasing severity of cirrhosis. In the whole blood clotting assay we observed delayed clot formation and decreased clot strength associated with increased severity of cirrhosis. No significant differences were found for tPA-ROTEM parameters of clot degradation.

CONCLUSION

These results indicate that cirrhosis patients have an overall procoagulant plasma milieu but a decreased whole blood clot formation capacity with an apparently unaltered resistance to clot lysis.

Does decreased fibrinolysis have a role to play in the development of non-neoplastic portal vein thrombosis in patients with hepatic cirrhosis?

Hepatic cirrhosis is characterized by complex abnormalities of the fibrinolytic system. Little is known about the possible association between these alterations and thrombosis. The aim of this study was to evaluate the fibrinolytic profile in cirrhotic individuals with and without portal vein thrombosis (PVT). We measured thrombin activatable fibrinolysis inhibitor (TAFI), total amount of activated TAFI (TAFIa/ai), plasminogen activator inhibitor (PAI-1), plasminogen and fibrinogen plasma levels in 66 cirrhotic patients (33 with and 33 without PVT) and in 66 healthy volunteers. TAFI plasma levels (median [range]) were significantly lower in cirrhotic individuals (5.6 μg/ml [1.7-11.7]) than in controls (10.1 μg/ml [6.6-14.2], p < 0.0001), while TAFIa/ai levels were significantly higher in cases (18.3 ng/ml [0.3-35.4]) than in controls (15.9 ng/ml [7.4-41], p = 0.02). Cirrhotic patients with PVT had higher TAFI (6.6 μg/ml [2.9-10.1]), TAFIa/ai (19.2 ng/ml [11.6-35.4]) and PAI-1 (33.1 ng/ml [27.6-56.3]) plasma levels than those without PVT (3.9 μg/ml [1.7-11.7], p = 0.001; 15.6 ng/ml [10.3-33.9], p = 0.037; 15.9 ng/ml [2.5-29.1], p = 0.004. The fibrinolytic profile in cirrhotic individuals with PVT is characterized by higher levels of TAFI, TAFIa/ai and PAI-1 than in those without PVT. These alterations identify a hypofibrinolytic condition that may increase the risk of developing a thrombotic event.

The antifibrinolytic drug tranexamic acid reduces liver injury and fibrosis in a mouse model of chronic bile duct injury

Hepatic fibrin deposition has been shown to inhibit hepatocellular injury in mice exposed to the bile duct toxicant α-naphthylisothiocyanate (ANIT). Degradation of fibrin clots by fibrinolysis controls the duration and extent of tissue fibrin deposition. Thus, we sought to determine the effect of treatment with the antifibrinolytic drug tranexamic acid (TA) and plasminogen activator inhibitor-1 (PAI-1) deficiency on ANIT-induced liver injury and fibrosis in mice. Plasmin-dependent lysis of fibrin clots was impaired in plasma from mice treated with TA (1200 mg/kg i.p., administered twice daily). Prophylactic TA administration reduced hepatic inflammation and hepatocellular necrosis in mice fed a diet containing 0.025% ANIT for 2 weeks. Hepatic type 1 collagen mRNA expression and deposition increased markedly in livers of mice fed ANIT diet for 4 weeks. To determine whether TA treatment could inhibit this progression of liver fibrosis, mice were fed ANIT diet for 4 weeks and treated with TA for the last 2 weeks. Interestingly, TA treatment largely prevented increased deposition of type 1 collagen in livers of mice fed ANIT diet for 4 weeks. In contrast, biliary hyperplasia/inflammation and liver fibrosis were significantly increased in PAI-1(-/-) mice fed ANIT diet for 4 weeks. Overall, the results indicate that fibrinolytic activity contributes to ANIT diet-induced liver injury and fibrosis in mice. In addition, these proof-of-principle studies suggest the possibility that therapeutic intervention with an antifibrinolytic drug could form a novel strategy to prevent or reduce liver injury and fibrosis in patients with liver disease.

Monitoring and managing hepatic disease in anaesthesia

Patients with liver disease have multisystem organ dysfunction that leads to physiological perturbations ranging from hyperbilirubinaemia of no clinical consequence to severe coagulopathy and metabolic disarray. Patient-specific risk factors, clinical scoring systems, and surgical procedures stratify perioperative risk for these patients. The anaesthetic management of patients with hepatic dysfunction involves consideration of impaired drug metabolism, hyperdynamic circulation, perioperative hypoxaemia, bleeding, thrombosis, and hepatic encephalopathy.

Hepatic coagulopathy-intricacies and challenges; a cross-sectional descriptive study of 110 patients from a superspecialty institute in North India with review of literature

Hemostatic defect in chronic liver disease (CLD) is complex involving opposing factors of primary hemostasis, coagulation, and fibrinolysis. The concept of causal relationship between abnormal tests and clinical bleeding is unclear. This study was undertaken to evaluate and correlate clinical bleeding and the commonly used laboratory tests for hemostasis in CLD patients including the subgroup of acute on chronic liver failure (ACLF) patients and test the reproducibility of international normalized ratio (INR) using different reagents. This was a cross-sectional descriptive study wherein clinical records and laboratory data from 110 patients (95 CLD, 15 ACLF) over a 6-month period were analysed. Variceal bleeding (33.3%) was the commonest followed by mucosal/skin bleeds (5.4%). Thrombocytopenia seen in 70.9% patients was mostly mild (48.2%) to moderate (14.5%). Prothrombin time (PT) prolongation was seen in 81.8% with significant variation in PT/INR using different reagents. Adverse outcome in the form of disseminated intravascular coagulation, septic shock or death was seen in 13.6% patients (eight ACLF and seven CLD). There was no correlation of bleeding with prolonged PT/INR, decreased platelet count and adverse clinical outcome. However, individually, there was significant but weak correlation between variceal bleeding and lower platelet count and superficial bleeding and prolonged PT. Correction of PT/INR post-fresh frozen plasma was significant but platelet count postplatelet concentrate transfusion was not. ACLF patients compared with CLD patients had greater PT prolongation and adverse outcome but no increase in bleeding. Routine tests, although globally deranged inadequately reflect haemostatic imbalance in CLD and poorly predict bleeding risk.

TAFI deficiency promotes liver damage in murine models of liver failure through defective down-regulation of hepatic inflammation

Emerging evidence indicates that various haemostatic components can regulate the progression of liver disease. Thrombin-activatable fibrinolysis inhibitor (TAFI) possesses anti-inflammatory properties besides its anti-fibrinolytic function. Here, we investigated the contribution of TAFI to the progression of disease in murine models of chronic and acute liver failure. Chronic carbon tetrachloride (CCL4) administration induced liver damage and fibrosis both in TAFI knockout (TAFI-/-) mice and wild-type controls. Smooth muscle actin-α (α-SMA) content of liver tissue was significantly increased after 1 and 3 weeks, and pro-collagen α1 expression was significantly increased after 3 and 6 weeks in TAFI-/- mice. TAFI-/- mice showed significantly elevated levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) after 3 weeks of CCL4. Neutrophil influx was significantly increased in TAFI-/- mice after 6 weeks of CCL4. No difference in hepatic fibrin deposition between TAFI-/- and wild-types was observed. After acetaminophen intoxication, necrosis was significantly increased in TAFI-/- mice at 24 hours (h) after injection. AST and ALT levels were decreased at 2 and 6 h after acetaminophen injection in TAFI-/- mice, but were significantly higher in the TAFI-/- mice at 24 h. Similarly, hepatic fibrin deposition was decreased at 6 h in TAFI-/- mice, but was comparable to wild-types at 24 h after injection. In conclusion, TAFI deficiency results in accelerated fibrogenesis and increased liver damage in murine models of chronic and acute liver disease, which may be related to increased inflammation.