Rebalanced hemostasis in patients with liver disease: evidence and clinical consequences. Blood. 2010;116:878-885. [PMID: 20400681 DOI: 10.1182/blood-2010-02-261891]

Abnormal hemostatic function one year after orthotopic liver transplantation can be fully attributed to endothelial cell activation

Background: The long-term risk of thrombotic and vascular complications is elevated in liver transplant recipients compared to the general population. Patients with cirrhosis are in a hypercoagulable status during and directly after orthotopic liver transplantation, but it is unclear whether this hypercoagulability persists over time.

Aim: We aimed to investigate the hemostatic status of liver transplant recipients one year after transplantation.

Methods: We prospectively collected blood samples of 15 patients with a functioning graft one year after orthotopic liver transplantation and compared the hemostatic status of these patients with that of 30 healthy individuals.

Results: Patients one year after liver transplantation had significantly elevated plasma levels of von Willebrand factor (VWF). Thrombin generation, as assessed by the endogenous thrombin potential, was decreased in patients, which was associated with increased plasma levels of the natural anticoagulants antithrombin and tissue factor pathway inhibitor.  Plasma fibrinolytic potential was significantly decreased in patients and correlated inversely with levels of plasminogen activator inhibitor-1.

Conclusion: One year after liver transplantation, liver graft recipients have a dysregulated hemostatic system characterised by elevation of plasma levels of endothelial-derived proteins. Increased levels of von Willebrand factor and decreased fibrinolytic potential may (in part) be responsible for the increased risk for vascular disease seen in liver transplant recipients.

Venous thromboembolic prophylaxis after a hepatic resection: patterns of care among liver surgeons

INTRODUCTION

No consensus exists for post-hepatectomy venous thromboembolic (VTE) prophylaxis. Factors impacting VTE prophylaxis patterns among hepato-pancreato-biliary (HPB) surgeons were defined.

METHOD

Surgeons were invited to complete a web-based survey on VTE prophylaxis. The impact of physician and clinical factors was analysed.

RESULTS

Two hundred responses were received. Most respondents were male (91%) and practiced at academic centres (88%) in the United States (80%). Surgical training varied: HPB (24%), transplantation (24%), surgical oncology (34%), HPB/transplantation (13%), or no specialty (5%). Respondents estimated VTE risk was higher after major (6%) versus minor (3%) resections. Although 98% use VTE prophylaxis, there was considerable variability: sequential compression devices (SCD) (91%), unfractionated heparin Q12h (31%) and Q8h (32%), and low-molecular weight heparin (39%). While 88% noted VTE prophylaxis was not impacted by operative indication, 16% stated major resections reduced their VTE prophylaxis. Factors associated with the decreased use of pharmacologic prophylaxis included: elevated international normalized ratio (INR) (74%), thrombocytopaenia (63%), liver insufficiency (58%), large EBL (46%) and complications (8%). Forty-seven per cent of respondents wait until ≥post-operative day 1 (POD1) and 35% hold pharmacologic VTE prophylaxis until no signs of coagulopathy. A minority (14%) discharge patients on pharmacologic prophylaxis. While 81% have institutional VTE guidelines, 79% believe hepatectomy-specific guidelines would be helpful.

CONCLUSION

There is considerable variation regarding VTE prophylaxis among liver surgeons. While most HPB surgeons employ VTE prophylaxis, the methods, timing and purported contraindications differ significantly.

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.

Natural course of nonmalignant partial portal vein thrombosis in cirrhotic patients

BACKGROUND/AIM

Portal vein thrombosis (PVT) has a high incidence in patients with liver cirrhosis and determines a poor prognosis of hepatic disease. The aim of our study was to define the natural course of partial PVT in cirrhotic patients, including survival and decompensation rates.

PATIENTS AND METHODS

We performed a prospective, cohort study, in a tertiary referral center. There were 22 cirrhotic patients with partial nonmalignant PVT, without anticoagulant treatment, who were followed-up between January 2011 and October 2013. All patients were evaluated by Doppler abdominal ultrasound and computed tomography. Kaplan-Meier method was used to determine the difference in clinical events between the study subgroups.

RESULTS

After a mean follow-up period of 20.22 months, partial PVT improved in 5 (22.73%), was stable in 11 (50%), and worsened in 6 (27.27%) patients. Hepatic decompensation rate at 6 and 18 months was higher in patients with worsened PVT than in those with stable/improved PVT (50% vs. 25%, P < 0.0001 and 100% vs. 56.25%, P < 0.0001, respectively). The survival rate at 6 months was 66.66% in worsened PVT group vs. 81.25% (P = 0.005) in stable/improved group, and 16.66% vs. 81.25% (P < 0.0001) at 18 months, respectively. Multivariate analysis showed that Model of End-Life Disease was the independent predictor of hepatic decompensation [hazard ratio (HR) 1.42; 95% confidence interval (CI): 1.08-1.87, P = 0.012] and survival (HR 1.76; 95% CI: 1.06-2.92, P = 0.028).

CONCLUSIONS

Nonmalignant partial PVT remained stable/improved in over half of cirrhotic patients and aggravated in more than one fourth in whom it negatively influenced the survival and decompensation rates.

Delicate balance of bleeding and thrombosis in end-stage liver disease and liver transplantation

Liver transplantation in cirrhotic patients is accompanied by severe bleeding. Indeed, the first 100 recipients of liver allografts transplanted by Thomas E. Starzl died mainly by uncontrolled bleeding. Since then, much progress has been made as to the understanding of the pathophysiology and the treatment of hemostatic disorders in cirrhotic patients. The aim of this review is to provide a state-of-the-art overview on recent developments and treatment options for hemostatic disorder in cirrhotic patients. Patients with end-stage-liver disease (ESLD) do not suffer only from procoagulant deficiency; there is also a lack of natural anticoagulants (i.e. proteins C and S) and profibrinolytics. Conventional laboratory methods such as the determination of the international normalized ratio or the activated partial thromboplastin time cannot predict bleeding complications in these patients. Progressive diagnostic techniques reveal that cirrhotic patients have the same capacity to produce thrombin like healthy volunteers. Moreover, cirrhotic patients--and particularly those with primary biliary cirrhosis or primary sclerosing cholangitis-- are at a higher risk for developing thrombosis as compared with healthy controls. Hemostatic alterations are common in cirrhotic patients; they involve both the pro- and the anticoagulant pathways. However, this is a very delicate balance, which may be shifted to either of these pathways by different treatments thereby causing bleeding or thrombosis, respectively.

Dispelling myths about coagulation abnormalities in internal medicine

The clotting screen is an 'integral' part of the routine blood tests in most medical wards. It is likely that only with the increasing requests for prothrombin time and activated partial thromboplastin time are abnormal results noted. Interpretation of these results requires good understanding of the coagulation system and problems with the laboratory analysis. Due to variable understanding of this complex system, many misconceptions have arisen in relation to the clinical effects expected from abnormal clotting screens. Some of these are discussed with considerations of appropriate management in those situations.

Coagulation management with factor concentrates in liver transplantation: a single-center experience

BACKGROUND

Allogeneic blood products transfusion during liver transplantation (LT) can be associated with increased morbidity and mortality. Data on thromboelastometry (ROTEM)-guided coagulation management with coagulation factor concentrates (CFCs)-fibrinogen concentrate and/or prothrombin complex concentrate (PCC)-are sparse. We aimed to retrospectively evaluate the safety events observed with this approach in our clinic.

STUDY DESIGN AND METHODS

LT patients from January 2009 to December 2010 (n = 266) were identified by chart review. A ROTEM-based algorithm with CFC guided the hemostatic therapy. Doppler ultrasound was used to evaluate thrombosis in the hepatic artery, portal vein, and hepatic veins. Stroke, myocardial ischemia, pulmonary embolism, and transfusion variables were recorded. Patients receiving CFC were included in the CFC group (n = 156); those not receiving CFC were included in the non-CFC group (n = 110). Safety events were compared between these two groups.

RESULTS

Allogeneic transfusion(s) in the 266 patients was low, with medians of 2 (interquartile range [IQR], 0-5), 0 (IQR 0-0), and 0 (IQR 0-1) units for red blood cells (RBCs), fresh-frozen plasma (FFP), and platelets (PLTs), respectively. Ninety-seven of 266 LTs (36.5%) were performed without RBCs transfusion, 227 (85.3%) without FFP, and 190 (71.4%) without PLTs. There were no significant differences in thrombotic, thromboembolic, and ischemic adverse events occurrence between the CFC group and the non-CFC group (11/156 patients vs. 5/110; p = 0.31).

CONCLUSION

In LT, ROTEM-guided treatment with fibrinogen concentrate and/or PCC did not appear to increase the occurrence of thrombosis and ischemic events compared to patients who did not receive these concentrates.

Abnormal hemostatic function one year after orthotopic liver transplantation can be fully attributed to endothelial cell activation

BACKGROUND

The long-term risk of thrombotic and vascular complications is elevated in liver transplant recipients compared to the general population. Patients with cirrhosis are in a hypercoagulable status during and directly after orthotopic liver transplantation, but it is unclear whether this hypercoagulability persists over time.

AIM

We aimed to investigate the hemostatic status of liver transplant recipients one year after transplantation.

METHODS

We prospectively collected blood samples of 15 patients with a functioning graft one year after orthotopic liver transplantation and compared the hemostatic status of these patients with that of 30 healthy individuals.

RESULTS

Patients one year after liver transplantation had significantly elevated plasma levels of von Willebrand factor (VWF). Thrombin generation, as assessed by the endogenous thrombin potential, was decreased in patients, which was associated with increased plasma levels of the natural anticoagulants antithrombin and tissue factor pathway inhibitor.  Plasma fibrinolytic potential was significantly decreased in patients and correlated inversely with levels of plasminogen activator inhibitor-1.

CONCLUSION

One year after liver transplantation, liver graft recipients have a dysregulated hemostatic system characterised by elevation of plasma levels of endothelial-derived proteins. Increased levels of von Willebrand factor and decreased fibrinolytic potential may (in part) be responsible for the increased risk for vascular disease seen in liver transplant recipients.

Importance of Kupffer cells in the development of acute liver injuries in mice

Kupffer cells reside within the liver sinusoid and serve as gatekeepers. They produce pro- and anti-inflammatory cytokines and other biologically important molecules upon the engagement of pattern recognition receptors such as Toll-like receptors. Kupffer cell-ablated mice established by in vivo treatment with clodronate liposomes have revealed many important features of Kupffer cells. In this paper, we review the importance of Kupffer cells in murine acute liver injuries and focus on the following two models: lipopolysaccharide (LPS)-induced liver injury, which is induced by priming with Propionibacterium acnes and subsequent challenge with LPS, and hypercoagulability-mediated acute liver failure such as that in concanavalin A (Con A)-induced hepatitis. Kupffer cells are required for LPS sensitization induced by P. acnes and are a major cellular source of interleukin-18, which induces acute liver injury following LPS challenge. Kupffer cells contribute to Con A-induced acute liver failure by initiating pathogenic, intrasinusoidal thrombosis in collaboration with sinusoidal endothelial cells. The mechanisms underlying these models may shed light on human liver injuries induced by various etiologies such as viral infection and/or abnormal metabolism.

Evidence of rebalanced coagulation in acute liver injury and acute liver failure as measured by thrombin generation

BACKGROUND & AIMS

Patients with liver disease often show profound abnormalities in their haemostatic system. Studies using thrombin generation demonstrate rebalanced coagulation in patients with chronic liver disease. Our aim was to evaluate the haemostatic profile in patients with acute liver injury/failure (ALI/ALF) compared with healthy controls.

METHODS

Thrombin generation was measured in the presence and absence of thrombomodulin (TM) to activate protein C (PC) with endogenous thrombin potential (ETP; the area under the thrombin generation curve) a key parameter. Routine coagulation assays were also performed.

RESULTS

Thirty two patients with ALI/ALF and 40 controls were recruited. Patients had grossly abnormal coagulation profiles with decreased pro- and anticoagulant factors compared with controls (P < 0.001 for all comparisons), except for median Factor VIII which was increased 247 U/dl [interquartile range: 214-347] in patients compared with 120 U/dl [97-139; P < 0.001] in controls. Mean ETP was significantly lower in patients 886 nM.min (± 436) compared with controls 1596 nM.min (± 259; P < 0.001). However, when the assay was repeated with TM to activate PC, there was no significant difference in mean ETP + TM between patients and controls (632 ± 418 vs 709 ± 301 nM.min respectively; P = 0.666). Furthermore, the ETP ratio (ETP + TM/ETP) was significantly higher in patients 0.89 (0.60-0.97) compared with controls 0.48 (0.3-0.6; P = 0.002) and negatively correlated with PC (R = -0.487, P = 0.003) and Factor V (R = -0.431, P = 0.01).

CONCLUSION

ALI/ALF patients have normal ETP in the presence of TM. This supports rebalanced coagulation mediated by acquired PC resistance because of the reduction in PC, Factor V and concomitant increase in Factor VIII.

Management of Bleeding in Post-liver Disease, Surgery and Biopsy in Patients With High Uncorrected International Normalized Ratio With Prothrombin Complex Concentrate: An Iranian Experience

Background:

To evaluate the efficacy of prothrombin complex concentrate (PCC) in the management of bleeding in patients with liver disease and patients undergoing surgery or biopsy who had a high uncorrected international normalized ratio (INR).

Objectives:

In this study, we examined an Iranian sample and investigated the efficacy of PCC to manage bleeding in patients with liver disease and also patients with high uncorrected INR who were scheduled for surgery or biopsy.

Materials and Methods:

A total of 25 patients including 16 patients with post-liver disease bleeding (group 1) and 9 patients with high uncorrected INR who were scheduled for surgery or biopsy (group 2) were enrolled. All patients were treated with 25 IU/kg PCC, and efficacy was defined as any reduction in or cessation of bleeding episodes and correction of INR before surgery or biopsy. The patients were also evaluated for any adverse effects.

Results:

INR decreased significantly in both groups of patients, with no bleeding episodes during or after the study in group 1 and during or after surgery/biopsy in group 2. All patients tolerated the therapy well without any significant adverse effects.

Conclusions:

The efficacy of PCC therapy was satisfactory in this study. PCC therapy in patients with liver disease and patients undergoing surgery or biopsy seems to be effective and safe, and may be a good treatment strategy for these patients, if fresh frozen plasma or vitamin K are not effective.

Point of care perioperative coagulation management in liver transplantation and complete portal vein thrombosis

Liver transplantation (LT) is a serious hemostatic challenge in patients with portal vein thrombosis (PVT). Advances in monitoring systems have improved surgery in this setting. We report the successful application of a point-of-care (POC) rotational viscoelastic thromboelastometry-guided (TEM) testing system (ROTEM) which allowed management of coagulation during LT in a 64-year-old cirrhotic patient with a model for end-stage liver disease (MELD) score of 16. Perioperatively, the patient showed complete PVT, hepatomegaly, splenomegaly, recanalization of the umbilical vein, and portosystemic shunt. Macroscopic liver and spleen adherences with collateral circulation were evident. Coagulation factors and fibrinolysis were assessed preoperatively and at graft reperfusion to evaluate the need of hemostatic therapy. Based on ROTEM findings, the patient received 16 g of human fibrinogen concentrate, half preoperatively (with prothrombin complex concentrate 2000 IU, tranexamic acid 1 g, and platelets 2 IU), and two doses of 4 g before and after graft reperfusion; we achieved normalization of all monitored parameters. No ischemia-reperfusion syndrome was present. Postoperatively portal vein flux at Color-Doppler ultrasonography was normal. After a 3-day ICU stay, the patient was moved to the Department of Surgery and discharged on day 14. The postoperative course was uneventful and did not require any further haemostatic therapy.

Hemostasis in liver disease: implications of new concepts for perioperative management

The hemostatic profile of patients with liver diseases is frequently profoundly different from that of healthy individuals. These complex alterations lead to abnormal results from routine laboratory tests, but because of the nature of these assays, they fail to accurately represent the patient's hemostatic state. Nevertheless, based on abnormal laboratory coagulation values, it has long been assumed that patients with liver disease have a natural bleeding tendency and are protected from thrombosis. This assumption is false; the average patient with liver disease is actually in a state of "rebalanced hemostasis" that can relatively easily be tipped toward both bleeding and thrombosis. The new paradigm of rebalanced hemostasis has strong implications for the clinic, which are presented in this review. There is no evidence that prophylactic transfusion of plasma helps to prevent procedure-related bleeding. In addition, the presence of independent risk factors such as poor kidney status or infections should be carefully assessed before invasive procedures. Furthermore, central venous pressure plays an important role in the risk of bleeding in patients with liver diseases, so during procedures, a restrictive infusion policy should be applied. Finally, thrombosis prophylaxis should not be withheld from patients with cirrhosis or acute liver failure, and clinicians should be alert to the possibility of thrombosis occurring in these patients.

Differential in vitro inhibition of thrombin generation by anticoagulant drugs in plasma from patients with cirrhosis

Background

Treatment and prevention of thrombotic complications is frequently required in patients with cirrhosis. However anticoagulant therapy is often withheld from these patients, because of the perceived bleeding diathesis. As a result of the limited clinical experience, the anticoagulant of choice for the various indications is still not known.

Objectives

We evaluated the in vitro effect of clinically approved anticoagulant drugs in plasma from patients with cirrhosis.

Patients/Methods

Thirty patients with cirrhosis and thirty healthy controls were studied. Thrombin generation assays were performed before and after addition of unfractionated heparin, low molecular weight heparin, fondaparinux, dabigatran, and rivaroxaban, to estimate anticoagulant potencies of these drugs.

Results

Addition of dabigatran led to a much more pronounced reduction in endogenous thrombin potential in patients compared to controls (72.6% reduction in patients vs. 12.8% reduction in controls, P<0.0001). The enhanced effect of dabigatran was proportional to the severity of disease. In contrast, only a slightly increased anticoagulant response to heparin and low molecular weight heparin and even a reduced response to fondaparinux and rivaroxaban was observed in plasma from cirrhotic patients as compared to control plasma.

Conclusions

The anticoagulant potency of clinically approved drugs differs substantially between patients with cirrhosis and healthy individuals. Whereas dabigatran and, to a lesser extent, heparin and low molecular weight heparin are more potent in plasma from patients with cirrhosis, fondaparinux and rivaroxaban showed a decreased anticoagulant effect. These results may imply that in addition to dose adjustments based on altered pharmacokinetics, drug-specific dose adjustments based on altered anticoagulant potency may be required in patients with cirrhosis.

Eltrombopag in patients with chronic hepatitis C and thrombocytopenia

ABSTRACT: 

Eltrombopag is a thrombopoietic drug that acts by interacting with the TPO receptor and stimulates megakaryocytopoiesis and platelet production. Thrombocytopenia is a fairly frequent hematological abnormality in patients with chronic liver disease, and may represent an obstacle to interferon-based antiviral therapy in patients with chronic HCV infection who are otherwise good candidates for treatment. In large, multicenter, randomized, placebo-controlled studies, eltrombopag consistently enabled thrombocytopenic chronic hepatitis C patients to be treated with interferon-based therapy and, as an adjunct to antiviral therapy, has shown to be able to increase the sustained virologic response rate to treatment. The safety profile of the drug, with particular attention to the risk of thromboembolic events and the potential for hepatic decompensation, should be taken into account when planning treatment. The aim of this article is to review the information currently available regarding the pharmacokinetics, clinical efficacy and side-effect profile of eltrombopag, and to assess the role of this drug into the current and future hepatitis C treatment paradigm.

Hemostasis, coagulation abnormalities, and liver disease

Coagulopathy-related bleeding events are a major concern in the management of acute and chronic liver disease. The liver attempts to maintain a balance between procoagulant and anticoagulant factors, and providers struggle with poor prognostic indicators to manage bleeding and critical complications. Subtle changes in patient presentation that may require extensive provider-directed interventions, such as blood transfusions, intravenous fluid management, mitigating possible sepsis, and evaluating appropriate pharmacologic treatment, are discussed.

Fresh frozen plasma: the most commonly prescribed hemostatic agent

Although fresh frozen plasma (FFP) is one of the most commonly prescribed therapies in clinical practice throughout the world today, there is little medical evidence available supporting its use. Recent guidelines have called for limiting FFP transfusions. Despite this, FFP use does not seem to be decreasing. The reasons for this are likely to be multifactorial, and may be based on ideas regarding medical practices dating back to Galen and Hippocrates. A review of the history of the development of FFP may shed some light on current clinical practice and guide the direction of future investigations and therapies.

Coagulopathies in the PICU: DIC and liver disease

Bleeding in patients in pediatric intensive care units is associated with an increased risk of mortality. Fortunately, most patients with an abnormal coagulation profile do not bleed because this is generally secondary to liver disease or dietary-induced vitamin K deficiency. When the laboratory markers of coagulopathy are the result of disseminated intravascular coagulation, bleeding is common and the risk of mortality extreme. Although interventions directed toward correcting the abnormal coagulation test results are generally initiated, they are also generally either not warranted or not fully successful.

An unbalance between von Willebrand factor and ADAMTS13 in acute liver failure: implications for hemostasis and clinical outcome

Emerging evidence supports the concept of a rebalanced hemostatic state in liver disease as a result of a commensurate decline in prohemostatic and antihemostatic drivers. In the present study, we assessed levels and functionality of the platelet-adhesive protein von Willebrand factor (VWF) and its cleaving protease ADAMTS13 in the plasma of patients with acute liver injury and acute liver failure (ALI/ALF). Furthermore, we explored possible associations between VWF, ADAMTS13, and disease outcome. We analyzed the plasma of 50 patients taken on the day of admission for ALI/ALF. The plasma of 40 healthy volunteers served as controls. VWF antigen levels were highly elevated in patients with ALI/ALF. In contrast, the collagen-binding activity and the ratio of the VWF ristocetin cofactor activity and VWF antigen was significantly decreased when compared with healthy controls. Also, the proportion of high molecular weight VWF multimers was reduced, despite severely decreased ADAMTS13 levels. In spite of these functional defects, platelet adhesion and aggregation were better supported by plasma of patients with ALI/ALF when compared with control plasma. Low ADAMTS13 activity, but not high VWF antigen, was associated with poor outcome in patients with ALI/ALF as evidenced by higher grades of encephalopathy, higher transplantation rates, and lower survival. VWF or ADAMTS13 levels were not associated with bleeding or thrombotic complications.

CONCLUSION

Highly elevated levels of VWF in plasma of patients with ALI/ALF support platelet adhesion, despite a relative loss of function of the molecule. Furthermore, low ADAMTS13 activity is associated with progressive liver failure in the patient cohort, which might be attributed to platelet-induced microthrombus formation in the diseased liver resulting from a substantially unbalanced VWF/ADAMTS13 ratio.

Established and new-generation antithrombotic drugs in patients with cirrhosis - possibilities and caveats

Until recently, it was widely accepted that patients with cirrhosis have a bleeding tendency related to the changes in the hemostatic system that occur as a consequence of the disease. However, it has now been well established that patients with cirrhosis are at risk for both bleeding and thrombotic complications. These thrombotic complications include portal vein thrombosis, deep vein thrombosis and pulmonary embolism, and coronary or cerebrovascular infarctions. Antithrombotic drugs to prevent or treat thrombotic complications in patients with cirrhosis have been used only minimally in the past due to the perceived bleeding risk. As the thrombotic complications and the necessity of antithrombotic treatment in these patients are increasingly recognized, the use of antithrombotic drugs in this population is likely increasing. Moreover, given the rising incidence of fatty liver disease and generally longer survival times of patients with chronic liver diseases, it would be reasonable to presume that some of these thrombotic complications may be increasing in incidence over time. In this review, we will outline the indications for antithrombotic treatment in patients with cirrhosis. Furthermore, we will discuss the available antithrombotic drugs and indicate possible applications, advantages, and caveats. Since for many of these drugs very little experience in patients with cirrhosis exists, these data are essential in the design of future clinical and laboratory studies on mechanisms, efficacy, and safety of the various antithrombotic strategies in these patients.

Decreased tissue factor pathway inhibitor (TFPI)-dependent anticoagulant capacity in patients with cirrhosis who have decreased protein S but normal TFPI plasma levels

Protein S acts as a cofactor for tissue factor pathway inhibitor (TFPI) in the down regulation of thrombin generation, and acquired and congenital protein S deficiencies are associated with a concomitant TFPI deficiency. In contrast, in patients with liver diseases, decreased protein S, but normal or increased levels of TFPI have been reported. We compared TFPI and protein S plasma levels between 26 patients with cirrhosis and 20 healthy controls and found that TFPI levels were comparable between patients (111 ± 38%) and controls (108 ± 27%), despite reduced protein S levels (74 ± 23% in patients vs. 98 ± 10% in controls). Subsequently, we quantified the activity of the TFPI-protein S system by measuring thrombin generation in the absence and presence of neutralizing antibodies to protein S or TFPI. Ratios of peak thrombin generation in the absence and presence of these antibodies were calculated. Both the protein S and the TFPI ratios were increased in patients with cirrhosis compared to controls. Protein S ratios were (0·62 [0·08-0·93] in patients vs. 0·32 [0·20-0·54] in controls; TFPI ratios were 0·50 [0·05-0·90] in patients vs. 0·18 [0·11-0·49] in controls). Thus, although the acquired protein S deficiency in patients with cirrhosis is not associated with decreased TFPI levels, the TFPI/protein S anticoagulant system is functionally impaired.

Hypercoagulability as a contributor to thrombotic complications in the liver transplant recipient

Traditionally, perioperative bleeding complications were a major concern during orthotopic liver transplantation, but a tremendous decline in transfusion requirements has been reported over the last decade. In recent years, there has been an increasing awareness towards perioperative thrombotic complications, including liver vessel thrombosis, and systemic venous and arterial thromboembolic events. Whereas a number of these thrombotic complications were previously categorized as surgical complications, increasing clinical and laboratory evidence suggest a role for the haemostatic system in thrombotic complications occurring during and after transplantation. High levels of the platelet adhesive protein von Willebrand factor with low levels of its regulator ADAMTS13, an increased potential to generate thrombin, and temporary hypofibrinolysis are all indicative of increased haemostatic potential after transplantation. Clinical evidence for a role of the haemostatic system in post-operative thromboses includes a higher thrombotic risk in patients with various acquired thrombotic risk factors. Although data on efficacy of anticoagulant therapy after liver transplantation are scarce, one study has shown a significant decrease in the risk for late hepatic artery thrombosis by antithrombotic therapy with aspirin. These findings suggest that antihaemostatic therapy in prevention or treatment of thromboembolic complications after liver transplantation may be relevant. Studies on efficacy and safety of these interventions are required as many of the thrombotic complications have a pronounced negative impact on graft and patient survival.

Prothrombin complex concentrate in the reduction of blood loss during orthotopic liver transplantation: PROTON-trial

BACKGROUND

In patients with cirrhosis, the synthesis of coagulation factors can fall short, reflected by a prolonged prothrombin time. Although anticoagulants factors are decreased as well, blood loss during orthotopic liver transplantation can still be excessive. Blood loss during orthotopic liver transplantation is currently managed by transfusion of red blood cell concentrates, platelet concentrates, fresh frozen plasma, and fibrinogen concentrate. Transfusion of these products may paradoxically result in an increased bleeding tendency due to aggravated portal hypertension. The hemostatic effect of these products may therefore be overshadowed by bleeding complications due to volume overload.In contrast to these transfusion products, prothrombin complex concentrate is a low-volume highly purified concentrate, containing the four vitamin K dependent coagulation factors. Previous studies have suggested that administration of prothrombin complex concentrate is an effective method to normalize a prolonged prothrombin time in patients with liver cirrhosis. We aim to investigate whether the pre-operative administration of prothrombin complex concentrate in patients undergoing liver transplantation for end-stage liver cirrhosis, is a safe and effective method to reduce perioperative blood loss and transfusion requirements.

METHODS/DESIGN

This is a double blind, multicenter, placebo-controlled randomized trial.Cirrhotic patients with a prolonged INR (≥1.5) undergoing liver transplantation will be randomized between placebo or prothrombin complex concentrate administration prior to surgery. Demographic, surgical and transfusion data will be recorded. The primary outcome of this study is RBC transfusion requirements.

DISCUSSION

Patients with advanced cirrhosis have reduced plasma levels of both pro- and anticoagulant coagulation proteins. Prothrombin complex concentrate is a low-volume plasma product that contains both procoagulant and anticoagulant proteins and transfusion will not affect the volume status prior to the surgical procedure. We hypothesize that administration of prothrombin complex concentrate will result in a reduction of perioperative blood loss and transfusion requirements. Theoretically, the administration of prothrombin complex concentrate may be associated with a higher risk of thromboembolic complications. Therefore, thromboembolic complications are an important secondary endpoint and the occurrence of this type of complication will be closely monitored during the study.

TRIAL REGISTRATION

The trial is registered at http://www.trialregister.nl with number NTR3174. This registry is accepted by the ICMJE.

Portal vein thrombosis: should anticoagulation be used?

Portal vein thrombosis (PVT) can contribute to significant morbidity and mortality; in patients with cirrhosis, this can make transplant more technically challenging. Additionally, the clot may extend further into the mesenteric and splenic veins, and disturbance of the hepatic blood flow may lead to faster progression of the cirrhosis. Development of PVT is associated with local risk factors, and many patients have associated systemic prothrombotic factors. Anticoagulation in noncirrhotic patients should be initiated at diagnosis, using low-molecular-weight heparin overlapping with vitamin K antagonists. Cirrhotic patients with PVT should be screened for varices and then anticoagulated with low-molecular-weight heparin for at least a 6-month period. All patients should be assessed for triggering factors and tumors, as well as systemic prothrombotic factors. Newer evidence suggests that prophylactic anticoagulation in patients with cirrhosis may have a role in clinical management with decreased incidence of PVT and improved survival; further study is needed.

Novel therapeutic strategies in adult acute lymphoblastic leukemia--a focus on emerging monoclonal antibodies

The outcomes in adult B-cell acute lymphoblastic leukemia (ALL) remain inferior to those achieved in pediatric populations. Targeted therapy with monoclonal antibodies may improve outcomes in adult B-cell ALL without significant additive toxicity. Rituximab is the best known monoclonal antibody and is routinely used in combination chemo-immunotherapy for treatment of adult B-cell ALL and Burkitts leukemia. A number of other monoclonal antibodies are currently under investigation for treatment of adult B-cell ALL including unconjugated antibodies (eg., ofatumumab, alemtuzumab and epratuzumab), antibodies conjugated to cytotoxic agents (eg., inotuzumab ozogamycin and SAR3419), antibodies conjugated to toxins such Pseudomonas or Diptheria toxins (eg., BL22 and moxetumomab pasudotox), and T-cell engaging bi-specific antibodies that redirect cytotoxic T lymphocytes to lyse target ALL cells (eg., blinatumomab). In this article we review the therapeutic implications, current status and results of monoclonal antibody-based therapy in adult B-cell ALL.

Coagulation imbalance may not contribute to the development of portal vein thrombosis in patients with cirrhosis

INTRODUCTION

The relationship between the imbalance in pro- and anti-coagulant factors and portal vein thrombosis (PVT) in individuals with cirrhosis is unclear. The aim of this study was to determine whether the imbalance in pro- and anti-coagulant factors contributes to the development of PVT in cirrhotic patients.

MATERIALS AND METHODS

Blood samples were collected from 30 consecutive cirrhotic patients with PVT and 30 age-, sex-, and Child-Pugh score-matched cirrhotic patients without PVT (controls), and the plasma levels of coagulation factors II, V, VII, VIII, IX, X, XI and XII and of protein C (PC), protein S (PS) and antithrombin (AT) were analyzed. The ratios of pro- vs. anti-coagulant factors were further investigated.

RESULTS

The levels of pro- and anti-coagulant factors were not statistically different between the PVT and control groups. Similar results were obtained when the patients were divided according to Child-Pugh classification. No difference was observed for the ratios of pro- vs. anti-coagulant factors between the two groups but the ratios of factor II-to-PC and factor VII-to-PC which were significantly decreased in the PVT group. Most of the ratios did not reach statistical significance in each Child-Pugh category except the followings: factor VIII-to-PS, factor XII-to-PC and factor XII-to-PS in class A patients; factor II-to-PS, factor VII-to-PC and factor VII-to-PS in class B patients. But the difference might not be so convincing.

CONCLUSIONS

PVT in cirrhotic patients may not result from coagulation imbalance.

Hemostatic defects in liver and renal dysfunction

Multiple and complex abnormalities of hemostasis are revealed by laboratory tests in such common diseases as cirrhosis and end-stage renal insufficiency. Because these abnormalities are associated with a bleeding tendency, a causal relationship is plausible. Accordingly, an array of transfusional and nontransfusional medications that improve or correct these abnormalities is used to prevent or stop hemorrhage. However, recent data indicate that the use of hemostatic drugs is scarcely justified mechanistically or clinically. In patients with uremia, the bleeding tendency (mainly expressed by gastrointestinal bleeding and hematoma formation at kidney biopsy) is reduced dramatically by the improvement of anemia obtained with the regular use of erythropoietin. In cirrhosis, the most severe and frequent hemorrhagic symptom (acute bleeding from esophageal varices) is not explained by abnormalities in such coagulation screening tests as the prothrombin and partial thromboplastin times, because formation of thrombin the final coagulation enzyme is rebalanced by low naturally occurring anticoagulant factors in plasma that compensate for the concomitant decrease of procoagulants. Rebalance also occurs for hyperfibrinolysis and platelet abnormalities. These findings are consistent with clinical observations that transfusional and nontransfusional hemostatic medications are of little value as adjuvants to control bleeding in advanced liver disease. Particularly in uremia, but also in cirrhosis, thrombosis is becoming a cogent problem.

Bleeding disorders in orthopedic surgery

With increasing recognition of the complications related to coagulopathies, it is of paramount importance for all orthopedic surgeons to possess a basic knowledge of common bleeding disorders. The evaluation of the coagulopathic patient requires a careful history, physical examination, and laboratory evaluation. Bleeding disorders commonly include quantitative and qualitative platelet and coagulation factor disorders and coagulation inhibitors. The management of these coagulopathies that can be encountered in elective and nonelective practice is often ignored. With appropriate knowledge and a multidisciplinary approach with hematologists and cardiologists, surgeons can perform minor and major orthopedic procedures safely and effectively.

Enoxaparin prevents portal vein thrombosis and liver decompensation in patients with advanced cirrhosis

BACKGROUND & AIMS

We performed a randomized controlled trial to evaluate the safety and efficacy of enoxaparin, a low-molecular-weight heparin, in preventing portal vein thrombosis (PVT) in patients with advanced cirrhosis.

METHODS

In a nonblinded, single-center study, 70 outpatients with cirrhosis (Child-Pugh classes B7-C10) with demonstrated patent portal veins and without hepatocellular carcinoma were assigned randomly to groups that were given enoxaparin (4000 IU/day, subcutaneously for 48 weeks; n = 34) or no treatment (controls, n = 36). Ultrasonography (every 3 months) and computed tomography (every 6 months) were performed to check the portal vein axis. The primary outcome was prevention of PVT. Radiologists and hepatologists that assessed outcomes were blinded to group assignments. Analysis was by intention to treat.

RESULTS

At 48 weeks, none of the patients in the enoxaparin group had developed PVT, compared with 6 of 36 (16.6%) controls (P = .025). At 96 weeks, no patient developed PVT in the enoxaparin group, compared with 10 of 36 (27.7%) controls (P = .001). At the end of the follow-up period, 8.8% of patients in the enoxaparin group and 27.7% of controls developed PVT (P = .048). The actuarial probability of PVT was lower in the enoxaparin group (P = .006). Liver decompensation was less frequent among patients given enoxaparin (11.7%) than controls (59.4%) (P < .0001); overall values were 38.2% vs 83.0%, respectively (P < .0001). The actuarial probability of liver decompensation was lower in the enoxaparin group (P < .0001). Eight patients in the enoxaparin group and 13 controls died. The actuarial probability of survival was higher in the enoxaparin group (P = .020). No relevant side effects or hemorrhagic events were reported.

CONCLUSIONS

In a small randomized controlled trial, a 12-month course of enoxaparin was safe and effective in preventing PVT in patients with cirrhosis and a Child-Pugh score of 7-10. Enoxaparin appeared to delay the occurrence of hepatic decompensation and to improve survival.

Liver transplantation: Advances and perioperative care

Liver transplantation is one of the treatments for many-life threatening liver diseases. Numerous advances in liver transplant surgery, anaesthesia and perioperative care have allowed for an increasing number of these procedures. The purpose of this review is to consider some of the important advances in perioperative care of liver transplant patients such as pre-operative evaluation, intraoperative monitoring and management and early extubation. A PubMed and EMBASE search of terms “Anaesthesia” and “Liver Transplantation” were performed with filters of articles in “English”, “Adult” and relevant recent publications of randomised control trial, editorial, systemic review and non-systemic review were selected and synthesized according to the author's personal and professional perspective in the field of liver transplantation and anaesthesia. The article outlines strategies in organ preservation, training and transplant database for further research.

Evidence for an enhanced fibrinolytic capacity in cirrhosis as measured with two different global fibrinolysis tests

BACKGROUND AND OBJECTIVES

It has been known for a long time that cirrhosis is associated with hyperfibrinolysis, which might contribute to an increased risk and severity of bleeding. However, recent papers have questioned the presence of a hyperfibrinolytic state in cirrhotic patients and postulated a rebalanced system owing to concomitant changes in both pro- and anti-fibrinolytic factors. Therefore we re-investigated the fibrinolytic state of cirrhotic patients using two different overall tests including a recently developed test for global fibrinolytic capacity (GFC) using whole blood.

PATIENTS AND METHODS

Blood was collected from 30 healthy controls and 75 patients with cirrhosis of varying severity (34 Child-Pugh A, 28 Child-Pugh B and 13 Child-Pugh C). The plasma clot lysis time (CLT), which is inversely correlated with fibrinolysis, was determined as well as the GFC.

RESULTS

The mean CLT was 74.5 min in the controls and decreased significantly to 66.9 min in Child-Pugh class A patients, 59.3 min in class B patients and 61.0 min in class C patients, and hyperfibrinolysis existed in 40% of the patients. The median GFC was 1.7 μg mL(-1) in the controls and increased significantly to 4.0 μg mL(-1) in Child-Pugh class A patients, 11.1 μg mL(-1) in class B patients and 22.5 μg mL(-1) in class C patients, and hyperfibrinolysis existed in 43% of the patients. Taken together, 60% of the patients showed hyperfibrinolysis in at least one of the two global assays.

CONCLUSION

A rebalanced fibrinolytic system may occur, but hyperfibrinolysis is found in the majority of patients with cirrhosis.

Usefulness of international normalized ratio to predict bleeding complications in patients with end-stage liver disease who undergo cardiac catheterization

Patients with end-stage liver disease frequently require invasive cardiac procedures in preparation for liver transplantation. Because of the impaired hepatic function, these patients often have a prolonged prothrombin time and elevated international normalized ratio (INR). To determine whether an abnormal prothrombin time/INR is predictive of bleeding complications from invasive cardiac procedures, we retrospectively reviewed, for bleeding complications, the databases and case records of our series of patients with advanced cirrhosis who underwent cardiac catheterization. A total of 157 patients underwent isolated right-sided heart catheterization, and 83 underwent left-sided heart catheterization or combined left- and right-sided heart catheterization. The INR ranged from 0.93 to 2.35. No major procedure-related complications occurred. Several patients in each group required a blood transfusion for gastrointestinal bleeding but not for procedure-related bleeding. No significant change was found in the hemoglobin after right-sided or left-sided heart catheterization, and no correlation was found between the preprocedure INR and the change in postprocedure hemoglobin. When comparing patients with a normal (≤1.5) and elevated (>1.5) INR, no significant difference in hemoglobin after the procedure was found in either group. In conclusion, despite an elevated INR, patients with end-stage liver disease can safely undergo invasive cardiac procedures. An elevated INR does not predict catheterization-related bleeding complications in this patient population.

A reappraisal of plasma, prothrombin complex concentrates, and recombinant factor VIIa in patient blood management

Plasma therapy and plasma products such as prothrombin complex concentrates (PCCs), and recombinant activated factor VII (rFVIIa) are used in the setting of massive or refractory hemorrhage. Their roles have evolved because of newly emerging options, variable availability, and heterogeneity in guidelines. These factors can be attributable to lack of evidence-based support for a defined role for plasma therapy, variability in coagulation factor content among PCCs, and uncertainty regarding safety and efficacy of rFVIIa in these settings. This review summarizes these issues and provides insight regarding use of these options in management of refractory or massive bleeding.

Anesthetic considerations for the patient with liver disease

PURPOSE OF REVIEW

An increasing number of patients requiring surgery are presenting with chronic or end stage liver disease. The management of these patients demands anesthesiologists with in-depth knowledge of the consequences of hepatic dysfunction, the effects on other organs, the risk of surgery, and the impact of anesthesia.

RECENT FINDINGS

Chronic or end stage liver disease is associated with an increased risk of perioperative morbidity and mortality. It is essential to preoperatively assess possible hepatic encephalopathy, pleural effusions, hepatopulmonary syndrome, hepatopulmonary hypertension, hepatorenal syndrome, cirrhotic cardiomyopathy, and coagulation disorders. The application of two scoring systems, that is, Child-Turcotte-Pugh and model for end stage liver disease, helps to estimate the risk of surgery. The use of propofol is superior to benzodiazepines as intravenous narcotics. Although enflurane and halothane are discouraged for maintenance of anesthesia, all modern volatile anesthetics appear comparable with respect to outcome. Fentanyl, sufentanil, and remifentanil as opioids and cis-atracurium for relaxation may be the best choices in liver insufficency. Regional anesthesia is valuable for postoperative pain management.

SUMMARY

Current studies have employed different anesthetic approaches in the preoperative and intraoperative management in order to improve outcomes of patients with liver disease.

Therapeutic administration of the direct thrombin inhibitor argatroban reduces hepatic inflammation in mice with established fatty liver disease

Thrombin generation is increased in patients with nonalcoholic fatty liver disease (NAFLD) and in mouse models of diet-induced obesity. Deficiency in the thrombin receptor protease activated receptor-1 reduces hepatic inflammation and steatosis in mice fed a Western diet. However, it is currently unclear whether thrombin inhibitors can modify the pathogenesis of established NAFLD. We tested the hypothesis that thrombin inhibition could reverse hepatic steatosis and inflammation in mice with established diet-induced NAFLD. Low-density lipoprotein receptor-deficient LDLr(-/-) mice were fed a control diet or a Western diet for 19 weeks. Mice were given the direct thrombin inhibitor argatroban ∼15 mg/kg/day or its vehicle via a miniosmotic pump for the final 4 weeks of the study. Argatroban administration significantly reduced hepatic proinflammatory cytokine expression and reduced macrophage and neutrophil accumulation in livers of mice fed a Western diet. Argatroban did not significantly impact hepatic steatosis, as indicated by histopathology, Oil Red O staining, and hepatic triglyceride levels. Argatroban reduced serum triglyceride and cholesterol levels in mice fed a Western diet. Argatroban reduced both α-smooth muscle actin expression and Type 1 collagen mRNA levels in livers of mice fed a Western diet, indicating reduced activation of hepatic stellate cells. This study indicates that therapeutic intervention with a thrombin inhibitor attenuates hepatic inflammation and several profibrogenic changes in mice fed a Western diet.

Intact thrombin generation and decreased fibrinolytic capacity in patients with acute liver injury or acute liver failure

BACKGROUND

It has been well established that hemostatic potential in patients with chronic liver disease is in a rebalanced status due to a concomitant decrease in pro- and antihemostatic drivers. The hemostatic changes in patients with acute liver injury/failure (ALI/ALF) are similar but not identical to the changes in patients with chronic liver disease and have not been studied in great detail.

OBJECTIVE

To assess thrombin generation and fibrinolytic potential in patients with ALI/ALF.

METHODS

We performed thrombin generation tests and clot lysis assays in platelet-poor plasma from 50 patients with ALI/ALF. Results were compared with values obtained in plasma from 40 healthy volunteers.

RESULTS AND CONCLUSION

The thrombin generation capacity of plasma from patients with ALI/ALF sampled on the day of admission to hospital was indistinguishable from that of healthy controls, provided thrombomodulin was added to the test mixture. Fibrinolytic capacity was profoundly impaired in patients with ALI/ALF on admission (no lysis in 73.5% of patients, compared with 2.5% of the healthy controls), which was associated with decreased levels of the plasminogen and increased levels of plasminogen activator inhibitor type 1. The intact thrombin generating capacity and the hypofibrinolytic status persisted during the first week of admission. Patients with ALI/ALF have a normal thrombin generating capacity and a decreased capacity to remove fibrin clots. These results contrast with routine laboratory tests such as the PT/INR, which are by definition prolonged in patients with ALI/ALF and suggest a bleeding tendency.

Coagulation in hepatobiliary disease

OBJECTIVE

To review the pathogenesis and clinical consequences of coagulation abnormalities accompanying hepatobiliary disorders and to highlight the need for further studies to characterize these derangements and their treatment options in small animal patients.

DATA SOURCES

Veterinary and human medical literature: original research articles, scientific reviews, consensus statements, and recent texts.

SUMMARY

The liver plays an important role in the production and clearance of many components of coagulation. A wide range of hemostatic derangements can occur in patients with hepatobiliary disease including alterations in platelet number and function, coagulation factor levels, anticoagulants, vascular endothelial function, and fibrinolysis. As these hemostatic alterations include both pro- and anticoagulation pathways, the net result is often a rebalanced hemostatic system that can be easily disrupted by concurrent conditions resulting in either clinical bleeding or thrombosis. Conventional coagulation tests are inadequate at identifying the spectrum of coagulation alterations occurring in patients with hepatobiliary disease, but their evaluation is necessary to assess bleeding risk and provide prognostic information. A paucity of information exists regarding the treatment of the coagulation derangements in small animals with hepatobiliary disease. Extrapolation from human studies provides some information about potential treatment options, but further studies are warranted in this area to elucidate the best management for coagulation abnormalities in dogs and cats with hepatobiliary disease.

CONCLUSION

Hepatobiliary disease can have profound effects on coagulation function leading to hypercoagulable or hypocoagulable states. Overall coagulation status with hepatobiliary disease depends on both the type and severity of disease and the presence of associated complications.

Risk of venous thromboembolism in patients with chronic liver disease and the utility of venous thromboembolism prophylaxis

OBJECTIVE

To review the current literature on the risk of venous thromboembolism (VTE) in patients with chronic liver disease (CLD).

DATA SOURCES

Literature was accessed through MEDLINE/PubMed (1996-December 2011) using the search terms liver disease, cirrhosis, venous thromboembolism, deep vein thrombosis, and pulmonary embolism.

STUDY SELECTION AND DATA EXTRACTION

Relevant observational and population-based studies were included to present background information. Bibliographies of all relevant articles were reviewed for additional citations.

DATA SYNTHESIS

Liver disease affects the synthesis of procoagulants and anticoagulants, resulting in hemostatic alterations and abnormal laboratory values. Retrospective studies characterized the VTE incidence to be 0.5-6.3%. Population-based studies reported VTE relative risks of 1.74-2.10 in patients with CLD compared with population controls and VTE odds ratios of 0.9-1.39 for hospitalized patients with CLD compared with controls without liver disease. There is a paucity of data on the use of pharmacologic prophylaxis in patients with CLD.

CONCLUSIONS

Patients with CLD should be assessed for VTE risk and given VTE prophylaxis when the benefits outweigh the risks. Diagnoses of CLD or elevated international normalized ratio do not confer protection against development of VTE and do not justify withholding pharmacologic prophylaxis based on this diagnosis.