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

The Best Anticoagulation Strategy for Cirrhotic Patients who Underwent Splenectomy: A Network Meta-Analysis

Objective

To determine the best anticoagulation strategy for the patients who underwent splenectomy with cirrhosis through network meta-analysis.

Methods

We conducted a systematic review of the literature in PubMed, Embase, and the Cochrane Library database. We extracted data on incidence of Portal vein system thrombosis (PVST) from studies that compared various anticoagulation strategies for use with patients who underwent splenectomy with cirrhosis. Network meta-analysis was conducted in ADDIS by evaluating the different incidence of PVST. Consistency and inconsistency models were developed to identify differences among the therapeutic strategies. Cumulative probability was utilized to rank the strategies under examination. Results. A total of 11 studies containing 1153 patients were included in the network meta-analysis. The results revealed that the application of Antithrombin III was the best anticoagulation option for patients who underwent splenectomy with cirrhosis (P = 0.59). The data of consistency and inconsistency models exhibited basically consistent and showed good convergence.

Conclusions

Application of Antithrombin III seemed to be the best anticoagulation strategy for cirrhotic patients who underwent splenectomy and should be considered a first-choice clinical reference.

Anticoagulation in chronic liver disease

In this Grand Round presentation, the case of a man with decompensated liver disease is described. He subsequently developed a fatal pulmonary embolism, which may not have occurred if he had been prescribed prophylactic anticoagulation to prevent venous thromboembolic disease. The burden of thrombotic disease in those with chronic liver disease is discussed, before a more detailed analysis of the current evidence, safety data, and clinical dilemmas regarding the use of anticoagulation in patients with chronic liver disease. Finally, the future directions within this field are explored.

Emerging therapeutic uses of direct-acting oral anticoagulants: An evidence-based perspective

Direct-acting oral anticoagulants (DOACs) were claimed to cause a potential paradigm shift in the therapeutic scenario of patients requiring short- and long-term anticoagulation, by virtue of their pharmacological properties, perceived as innovative. The evidence gathered so far (from pre-approval pivotal trials to real-world post-marketing observational data) consistently confirmed that DOACs are overall comparable to vitamin-K antagonists (VKAs) in terms of safety, efficacy and effectiveness and unequivocally documented a consistent and clinically relevant reduced risk of intracranial bleeding in the settings of non-valvular atrial fibrillation (NVAF) and venous thromboembolism (VTE). Interestingly, two parallel paths can be identified in the current research scenario: A) in the aforementioned consolidated therapeutic indications, an innovative approach is directed towards tailored treatment strategies, to identify patients most likely to benefit from one of the different anticoagulant drugs, in particular subpopulations at increased risk of adverse events (e.g., bleeding); B) in unconventional settings, DOACs are gaining interest for potential use in emerging diseases characterized by arterial and venous thromboembolic risk. In these scenarios, the risk-benefit profile of DOACs, as compared to VKAs or heparins, is less defined. The aim of this review is to critically assess the body of evidence underlying emerging therapeutic uses of DOACs (e.g., heparin-induced thrombocytopenia, anti-phospholipid antibody syndrome), including evolving issues in special populations (e.g., patients with VTE and cancer or cirrhosis). This will be achieved by analyzing the strength (i.e., systematic reviews, randomized clinical trials, observational studies, case report/series) and consistency (i.e., concordance) of both published and unpublished evidence registered in major public repositories.

Von Willebrand factor deficiency reduces liver fibrosis in mice

Liver diseases are associated with complex changes in the hemostatic system and elevated levels of the platelet-adhesive protein Von Willebrand factor (VWF) are reported in patients with acute and chronic liver damage. Although elevated levels of VWF are associated with fibrosis in the general population, the role of VWF in acute and chronic liver injury has not been examined in depth in experimental settings. We tested the hypothesis that VWF deficiency inhibits experimental liver injury and fibrosis. Wild-type (WT) and VWF-deficient mice were challenged with carbon tetrachloride (CCl₄) and the impact of VWF deficiency on acute liver injury and chronic liver fibrosis was determined. VWF deficiency did not significantly affect acute CCl₄-induced hepatocellular necrosis in mice. Chronic CCl₄ challenge, twice weekly for 6weeks, significantly increased hepatic stellate cell activation and collagen deposition in livers of WT mice. Interestingly, hepatic induction of several profibrogenic and stellate cell activation genes was attenuated in VWF-deficient mice. Moreover, birefringent sirius red staining (indicating type I and III collagens) and type I collagen immunofluorescence indicated a reduction in hepatic collagen deposition in CCl₄-exposed VWF-deficient mice compared to CCl₄-exposed WT mice. The results indicate that VWF deficiency attenuates chronic CCl₄-induced liver fibrosis without affecting acute hepatocellular necrosis. The results are the first to demonstrate that VWF deficiency reduces the progression of liver fibrosis, suggesting a mechanistic role of elevated plasma VWF levels in cirrhosis.

Antithrombotic treatment with direct-acting oral anticoagulants in patients with splanchnic vein thrombosis and cirrhosis

BACKGROUND

Direct-acting oral anticoagulants (DOACs) are used in patients with splanchnic vein thrombosis (SVT) and cirrhosis, but evidence for safety and efficacy in this setting is limited. Our aim was to identify indications and reasons for starting or switching to DOACs and to report adverse effects, complications and short-term outcome.

METHODS

Data collection including demographic information, laboratory values, treatment and complications through the Vascular Liver Disease Interest Group Consortium.

RESULTS

Forty-five centres (90%) of the consortium completed the initial eCRF. We report here a series of 94 patients from 17 centres. Thirty-six patients (38%) had cirrhosis. Child-Pugh score was 6 (range 5-8), and MELD score 10.2 (range 6-19). Indications for anticoagulation were splanchnic vein thrombosis (75%), deep vein thrombosis (5%), atrial fibrillation (14%) and others (6%). DOACs used were rivaroxaban (83%), dabigatran (11%) and apixaban (6%). Patients were followed up for a median duration of 15 months (cirrhotic) and 26.5 months (non-cirrhotic). Adverse events occurred in 17% of patients and included one case of recurrent portal vein thrombosis and five cases of bleeding. Treatment with DOACs was stopped in three cases. The major reasons for choosing DOACs were no need for monitoring or inadequacy of INR to guide anticoagulation in cirrhotic patients. Renal and liver function did not change during treatment.

CONCLUSIONS

A consistent number of patients with SVT and/or cirrhosis are currently treated with DOACs, which seem to be effective and safe. These data provide a basis for performing randomized clinical trials of DOACs vs. low molecular weight heparin or vitamin K antagonists.

Impact of coagulation function and anticoagulation therapy on liver fibrosis

Liver cirrhosis and its complications, including esophageal and gastric variceal bleeding, hepatic encephalopathy, and ascites, can cause serious harm to human health. Therefore, treatment of liver fibrosis is key to the prevention and treatment of liver cirrhosis. In order to treat liver fibrosis to reduce human suffering, medical experts and scholars have performed many clinical and animal studies to find safe, efficient and reliable drugs to slow the progression of hepatic fibrosis and even reverse the liver function. This review introduces the definition of liver fibrosis in China and other countries, discusses the effect of coagulation on the process of liver fibrosis and various anticoagulation therapies for liver fibrosis, and summarizes the advantages, disadvantages, and side effects of different anticoagulants in the prevention and treatment of liver fibrosis.

Hemostasis, bleeding and thrombosis in liver disease

The presence of cirrhosis poses an increased risk of both thrombosis and bleeding in individuals with chronic liver disease. This duality is a result of a dynamic disequilibrium between procoagulant and anticoagulant states in individuals with cirrhosis. The mechanism of this imbalance in cirrhosis remains unclear. It is known that the progression of cirrhosis leads to decreased synthetic function and a concurrent lack of natural anticoagulants. Other proposed mechanisms contributing to this hemostatic imbalance include decreased platelet production, increased platelet destruction from hypersplenism, decreased synthesis of Vitamin K-dependent and independent clotting factors and anticoagulant factors, and alterations in purinergic signaling pathways.

Given the current state of flux in our understanding of bleeding and thrombophilia in cirrhosis, the recommendations for treatment of these conditions are still evolving.

We provide a current update on the proposed pathophysiology of altered hemostasis and thrombophilia in cirrhosis. We discuss recent studies in portal vein thrombosis (PVT) and venous thromboembolism (VTE), which are the common thrombotic consequences of cirrhosis, resulting in substantive morbidity and mortality. To address these, we discuss new prophylactic interventions and current treatment options to manage the heightened risk of thrombosis in cirrhosis, while limiting hemorrhagic complications.

The efficacy and safety of direct oral anticoagulants vs traditional anticoagulants in cirrhosis

INTRODUCTION

The coagulopathy of cirrhosis is complex, placing patients at risk for both bleeding and thrombosis. Direct oral anticoagulants (DOACs) have equivalent or superior efficacy and safety as compared to vitamin K antagonists (VKAs); however, their efficacy and safety in liver cirrhosis has not been studied. To better define this, we evaluated outcomes of patients with cirrhosis prescribed DOACs compared to other anticoagulants at our center.

METHODS

Retrospective cohort study of patients with cirrhosis prescribed therapeutic anticoagulation over a 3-year period for thrombosis or prevention of stroke in patients with atrial fibrillation. The primary outcomes of interest were bleeding events and recurrent thrombosis or stroke.

RESULTS

During the study period, 27 patients with cirrhosis were prescribed a DOAC and 18 were prescribed VKA or low molecular weight heparin (LMWH). Both groups had similar total bleeding events (8 DOAC vs 10 other, P=.12). There were significantly less major bleeding episodes in the DOAC group (1 [4%] vs 5 [28%], P=.03). Recurrent thrombosis occurred in one patient receiving a DOAC (4%) and one patient (6%) receiving other anticoagulation (P=1.0).

CONCLUSIONS

Direct oral anticoagulant use in patients with cirrhosis may be as safe as traditional anticoagulants. Patients with cirrhosis at our center prescribed DOACs had less major bleeding events, while maintaining efficacy at preventing stroke or thrombosis.

Thrombosis and anticoagulation in the setting of renal or liver disease

Thrombosis and bleeding are among the most common causes of morbidity and mortality in patients with renal disease or liver disease. The pathophysiology underlying the increased risk for venous thromboembolism and bleeding in these 2 populations is distinct, as are considerations for anticoagulation. Anticoagulation in patients with kidney or liver disease increases the risk of bleeding; this risk is correlated with the degree of impairment of anticoagulant elimination by the kidneys and/or liver. Despite being in the same pharmacologic category, anticoagulant agents may have varied degrees of renal and liver metabolism. Therefore, specific anticoagulants may require dose reductions or be contraindicated in renal impairment and liver disease, whereas other drugs in the same class may not be subject to such restrictions. To minimize the risk of bleeding, while ensuring an adequate therapeutic effect, both appropriate anticoagulant drug choices and dose reductions are necessary. Renal and hepatic function may fluctuate, further complicating anticoagulation in these high-risk patient groups.

Portal vein thrombosis relevance on liver cirrhosis: Italian Venous Thrombotic Events Registry

Portal vein thrombosis may occur in cirrhosis; nevertheless, its prevalence, and predictors are still elusive. To investigate this issue, the Italian Society of Internal Medicine undertook the "Portal vein thrombosis Relevance On Liver cirrhosis: Italian Venous thrombotic Events Registry" (PRO-LIVER). This prospective multicenter study includes consecutive cirrhotic patients undergoing Doppler ultrasound examination of the portal area to evaluate the prevalence and incidence of portal vein thrombosis over a 2-year scheduled follow-up. Seven hundred and fifty-three (68 % men; 64 ± 12 years) patients were included in the present analysis. Fifty percent of the cases were cirrhotic outpatients. Viral (44 %) etiology was predominant. Around half of the patients had a mild-severity disease according to the Child-Pugh score; hepatocellular carcinoma was present in 20 %. The prevalence of ultrasound-detected portal vein thrombosis was 17 % (n = 126); it was asymptomatic in 43 % of the cases. Notably, more than half of the portal vein thrombosis patients (n = 81) were not treated with anticoagulant therapy. Logistic step-forward multivariate analysis demonstrated that previous portal vein thrombosis (p < 0.001), Child-Pugh Class B + C (p < 0.001), hepatocellular carcinoma (p = 0.01), previous upper gastrointestinal bleeding (p = 0.030) and older age (p = 0.012) were independently associated with portal vein thrombosis. Portal vein thrombosis is a frequent complication of cirrhosis, particularly in patients with moderate-severe liver failure. The apparent undertreatment of patients with portal vein thrombosis is a matter of concern and debate, which should be addressed by planning interventional trials especially with newer oral anticoagulants. Clinicaltrials.gov identifier NCT01470547.

Role of inferior vena cava filters in transplant patients

PURPOSE

This study evaluates the selection, use, and risks of permanent and retrievable inferior vena cava filters (IVCFs) in patients who have undergone organ transplantation.

MATERIALS AND METHODS

Single-center retrospective review of 35 patients who had an IVCF placed following organ transplantation. Patient demographics, IVCF indication, and eligibility for retrieval were reviewed. Computed tomography (CT) studies showing the filter (n=22) were evaluated independently for IVCF adverse effects.

RESULTS

Thirty-two (91%) of 35 patients had retrievable IVCFs placed while three (9%) patients received permanent IVCFs. Filter retrieval was indicated in three of the 32 patients receiving retrievable filters and was performed in two cases. Patients were ineligible for retrieval due to short life expectancy, complications/contraindications to anticoagulation, extended filter dwell time, lost to follow-up, and undetermined therapeutic value of anticoagulation.

CONCLUSION

Current practices of filter placement usually dictate placing a retrievable IVCF in transplant patients. However, transplant patients are unlikely to be eligible for filter retrieval especially in situations of advanced age and comorbidities. Given the low incidence of eligibility for retrieval in this patient population, these results suggest preferential placement of permanent filters may reduce the potential morbidity due to filter-related complications, such as strut perforation, in transplant patients.

Bleeding Risk and Management in Interventional Procedures in Chronic Liver Disease

The coagulopathy of liver disease is distinctly different from therapeutic anticoagulation in a patient. Despite stable elevated standard clot-based coagulation assays, nearly all patients with stable chronic liver disease (CLD) have normal or increased clotting. Common unfamiliarity with the limitations of these assays in CLD may lead to inappropriate and sometimes harmful interventions, including blood product transfusions before a procedure. Knowledge of the distinct hemostatic alterations in CLD can allow identification of the small subset of patients with clinically significant coagulopathy who can benefit from hematologic optimization before invasive procedures.

Anticoagulation in Patients With Cirrhosis: Caught Between a Rock-Liver and a Hard Place

OBJECTIVE

To review current literature for anticoagulation in patients with cirrhosis and provide a summary of the effects of cirrhosis on the coagulation cascade, therapeutic monitoring through interpretation of antifactor Xa (anti-Xa), activated partial thromboplastin time (aPTT), and international normalized ratio (INR) as well as current prophylaxis and treatment recommendations in cirrhotic patients.

METHODS

A systematic electronic literature search was conducted in PubMed using the key termsanticoagulation, warfarin, low-molecular-weight heparin(LMWH),unfractionated heparin(UFH),target-specific oral anticoagulants, deep-vein thrombosis(DVT),pulmonary embolism(PE),portal vein thrombosis(PVT),venous thromboembolism, anti-Xa, activated partial thromboplastin time, anticoagulation therapeutic monitoring, coagulopathy, coagulation cascade, chronic liver disease, cirrhosis, anddecompensated liver disease

STUDY SELECTION

Studies written in the English language from January 2000 to December 2015 were considered for this review article. All search results were reviewed, and the relevance of each article was determined by authors independently.

CONCLUSIONS

Patients with cirrhosis are at higher risk for both bleeding and thrombosis-related complications. Cirrhosis affects production of both procoagulant and anticoagulant factors, thus resulting in increased INR and aPTT levels and decreased anti-Xa levels. LMWH is the treatment of choice for the prevention and treatment of DVT/PE/PVT in patients with cirrhosis, and monitoring with anti-Xa levels for dose adjustment is not recommended. UFH is an alternative in cirrhotic patients for shorter-term use and in cases of severe renal dysfunction and/or hemodynamic instability. Cirrhotic patients on anticoagulation therapy should be monitored closely for signs and symptoms of bleeding and thrombosis.

Changing common sense: Anti-platelet/coagulation therapy against cirrhosis

Until recently, anti-platelet/coagulation therapy had not been recommended for patients with cirrhosis. Although venous thrombosis is one of the representative complications of cirrhosis and ischemic disorders associated with atherosclerosis are not infrequent in cirrhotic patients, many clinicians have tended to hesitate to introduce anti-platelet/coagulation therapy to their patients. Undoubtedly, this is due to the increased risk of hemorrhagic diathesis in cirrhotic patients. However, accumulating evidence has revealed the benefits of anti-platelet/coagulation therapy for cirrhotic patients. In addition to the safety of the therapy carried out against cardiovascular diseases in cirrhotic patients, some clinical data have indicated its preventive effect on venous thrombosis. Moreover, the efficacy of anti-platelet/coagulation therapy against cirrhosis itself has been demonstrated both clinically and experimentally. The conceptual basis for application of anti-platelet/coagulation therapy against cirrhosis was constructed through two pathologic studies on intrahepatic thrombosis in cirrhotic livers. It may be better to use thrombopoietin-receptor agonists, which have been tested as a treatment for cirrhosis-related thrombocytopenia, in combination with anti-platelet drugs to reduce the risk of venous thrombosis. During the last decade, the World Journal of Gastroenterology, a sister journal of World Journal of Hepatology, has been one of the main platforms of active discussion of this theme.

Safety and efficacy of pharmacological thromboprophylaxis for hospitalized patients with cirrhosis: a single-center retrospective cohort study

BACKGROUND

Hospitalized patients with cirrhosis are at increased risk for venous thromboembolism (VTE). The benefits and risks of pharmacological thromboprohylaxis in these patients have not been well studied.

OBJECTIVES

To examine the safety and efficacy of pharmacological VTE prophylaxis in hospitalized cirrhotic patients.

PATIENTS/METHODS

Retrospective cohort study of patients with cirrhosis hospitalized at an academic tertiary care referral center over a 5-year period.

RESULTS

Six hundred hospital admissions accounting for 402 patients were included. VTE prophylaxis was administered during 296 (49%) admissions. Patients receiving VTE prophylaxis were older (59 years vs. 55 years, P < 0.001), had longer lengths of stay (9.6 days vs. 6.8 days, P = 0.002), and lower Model for End-Stage Liver Disease scores (13.2 vs. 16.1, P < 0.001). In-hospital bleeding events (8.1% vs. 5.5%, P = 0.258), gastrointestinal bleeding events (3.0% vs. 3.2% P = 0.52), new VTE events (2.37% vs. 1.65%, P = 0.537), and mortality (8.4% vs. 7.3%, P = 0.599) were similar in the two groups. VTE prophylaxis did not reduce the risk of VTE (odds ratio 0.94, 95% confidence interval 0.23-3.71), and patients receiving unfractionated heparin, but not low molecular weight heparin, were at increased risk for in-hospital bleeding events (odds ratio 2.38, 95% confidence interval 1.15-4.94 vs. 0.87, 0.37-2.05, respectively).

CONCLUSION

The rate of VTE in this cohort of hospitalized cirrhotic patients was low and was unaffected by pharmacological thromboprophylaxis. Unfractionated heparin was associated with an increased risk for in-hospital bleeding, suggesting that if thromboprophylaxis is indicated, low molecular weight heparin may be favored.

Laparoscopic Splenectomy with Technical Standardization and Selection Criteria for Standard or Hand-Assisted Approach in 390 Patients with Liver Cirrhosis and Portal Hypertension

BACKGROUND

Laparoscopic splenectomy (LS) is still challenging in patients with liver cirrhosis and portal hypertension. This study was designed to establish safe and less invasive LS in patients with liver cirrhosis and portal hypertension.

STUDY DESIGN

We analyzed 390 patients with liver cirrhosis and portal hypertension, who underwent LS between 1993 and 2013. Patients were divided into 3 time periods; early (1993 to 2004, n = 106); middle (2005 to 2008, n = 159); and late (2008 to 2013, n = 125). During the middle time period, standardized technique for LS and selection criteria for hand-assisted LS were adopted. Patients with spleen volume ≥ 1,000 mL by CT volumetry, large perisplenic collateral vessels, and/or Child-Pugh score ≥ 9, underwent hand-assisted LS. During the late time period, the selection criteria were refined and patients with spleen volume ≥ 600 mL underwent hand-assisted LS.

RESULTS

Conversion to open splenectomy decreased (10.4% in the early time period, 1.9% in the middle time period, and 3.2% in the late time period, p = 0.004), median blood loss decreased (300g, 87g, and 98g, respectively, p < 0.001), and the success rate of pure LS tended to improve (87.2%, 89.5%, and 98.0%, respectively, p = 0.110). Mortality was 0% in each time period, Clavien-Dindo grade IIIb or more complications tended to decrease (5.7%, 2.5%, and 0.8%, respectively, p = 0.081), and technique-related complications decreased significantly (10.4%, 3.8%, and 2.4%, respectively, p = 0.014).

CONCLUSIONS

Laparoscopic splenectomy is now a safe and less invasive approach, even in patients with liver cirrhosis and portal hypertension, because of its technical standardization with the refined selection criteria for pure or hand-assisted LS.

Progress in treatment of nontumoral portal vein thrombosis in liver cirrhosis

Portal vein thrombosis (PVT) is not uncommon in patients with liver cirrhosis, and it increases the risk of gastroesophageal hemorrhage. At present, pharmacological treatment is the preferred selection of management of PVT. Studies have shown that anticoagulation therapy does not increase the risk of gastrointestinal bleeding. Therefore, patients having indications should be given anticoagulation therapy as early as possible. When patients fail to respond to anticoagulation therapy, interventional therapy or surgery may be considered. This article reviews the recent knowledge about the treatment of PVT and discusses the progress in treatment of nontumoral PVT in liver cirrhosis.

Managing complications in cirrhotic patients

Liver cirrhosis is a serious and potentially life-threatening condition. This life-threatening condition usually arises from complications of cirrhosis. While variceal bleeding is the most acute and probably best studied, several other complications of liver cirrhosis are more insidious in their onset but nevertheless more important for the long-term management and outcome of these patients. This review summarizes the topics discussed during the UEG-EASL Hepatology postgraduate course of the United European Gastroenterology Week 2013 and discusses emergency surgical conditions in cirrhotic patients, the management of hepatic encephalopathy, ascites and hepatorenal syndrome, coagulation disorders, and liver cancer.

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.

The coagulation system in patients with end-stage liver disease

In patients with cirrhosis, routine laboratory tests for primary hemostasis and coagulation usually show anomalies that are associated with excess bleeding in other settings, in particular low platelet counts and prolonged prothrombin time. However, under conditions similar to those in vivo, primary hemostasis and thrombin production do not appear to be decreased in patients with cirrhosis, particularly when the platelet count is above 75,000/μl. Furthermore, there is laboratory and epidemiological evidence of a mild procoagulant and prothrombotic state in patients with cirrhosis. Bleeding is mainly because of portal hypertension rather than defective hemostasis. There is some evidence that anticoagulation therapy is not associated with an excess of severe bleeding and that it could improve the outcome in patients without portal vein thrombosis. At present, there is no clear evidence that portal vein thrombosis is responsible for the progression of liver disease and that anticoagulation therapy would improve the outcome of patients with portal vein thrombosis.

Eptifibatide and Cirrhosis: Rethinking GPIIb-IIIa Inhibitors for Acute Coronary Syndrome in the Setting of Liver Dysfunction

Glycoprotein IIb/IIIa (GPIIb/IIIa) inhibitors, such as eptifibatide, are routinely used in the setting of acute coronary syndrome (ACS) prior to or during percutaneous coronary intervention (PCI). While numerous studies have demonstrated improved clinical outcomes with eptifibatide use, adverse effects including thrombocytopenia have also been noted. For this reason, patients with baseline thrombocytopenia or liver disease should be cautiously evaluated prior to drug administration. Here we report a case of acute profound and prolonged eptifibatide-induced thrombocytopenia in a patient with cirrhotic liver dysfunction. We propose and discuss the need for a risk stratification tool to be established for identifying which patients with ACS in the setting of chronic liver disease receive GPIIb/IIIa inhibitors.

Portal vein thrombosis in cirrhosis

Portal vein thrombosis (PVT) is being increasingly recognized in patients with advanced cirrhosis and in those undergoing liver transplantation. Reduced flow in the portal vein is probably responsible for clotting in the spleno-porto-mesenteric venous system. There is also increasing evidence that hypercoagulability occurs in advanced liver disease and contributes to the risk of PVT. Ultrasound based studies have reported a prevalence of PVT in 10-25% of cirrhotic patients without hepatocellular carcinoma. Partial thrombosis of the portal vein is more common and may not have pathophysiological consequences. However, there is high risk of progression of partial PVT to complete PVT that may cause exacerbation of portal hypertension and progression of liver insufficiency. It is thus, essential to accurately diagnose and stage PVT in patients waiting for transplantation and consider anticoagulation therapy. Therapy with low molecular weight heparin and vitamin K antagonists has been shown to achieve complete and partial recanalization in 33-45% and 15-35% of cases respectively. There are however, no guidelines to help determine the dose and therapeutic efficacy of anticoagulation in patients with cirrhosis. Anticoagulation therapy related bleeding is the most feared complication but it appears that the risk of variceal bleeding is more likely to be dependent on portal pressure rather than solely related to coagulation status. TIPS has also been reported to restore patency of the portal vein. Patients with complete PVT currently do not form an absolute contraindication for liver transplantation. Thrombectomy or thromboendovenectomy is possible in more than 75% of patients followed by anatomical end-to-end portal anastomosis. When patency of the portal vein and/or superior mesenteric vein is not achieved, only non-anatomical techniques (reno-portal anastomosis or cavo-portal hemitransposition) can be performed. These techniques, which do not fully reverse portal hypertension, are associated with higher morbidity and mortality risks in the short term.

Is there a rationale for treatment of chronic liver disease with antithrombotic therapy?

Recent advances in the understanding of the coagulopathy in chronic liver disease have provided a strong support for anticoagulation as a new therapeutic paradigm for patients with cirrhosis. Laboratory studies indicate that the net effect of changes in hemostasis in many patients with chronic liver disease is a hypercoagulable status. In turn, clinical thrombosis is increasingly recognized as a complication of liver disease. When occurring within the liver, thrombosis may even progress the disease course. Exciting preliminary data regarding the potential of low-molecular-weight heparin to slow down the progression of liver disease indicate that this class of drugs may improve outcome without a major increase in bleeding risk. However, this new era for antithrombotic therapy in chronic liver disease is still hindered by a persistent false notion that patients with cirrhosis are "auto-anticoagulated" by their underlying liver disease. In addition, there is insufficient clinical evidence on safety and efficacy of anticoagulant therapy in cirrhosis and the studies conducted so far are limited by small sample sizes, uncontrolled treatment arms, or by their retrospective nature. Finally, a lack of knowledge on how or when to monitor antithrombotic treatment to optimize the risk-benefit ratio has restricted a widespread application of anticoagulant treatment in clinical management algorithms. Nonetheless, by systematically covering possibilities and pitfalls, this review highlights the potential of antithrombotic therapy to improve the quality of life and the clinical outcome of patients with chronic liver disease.

Optimizing risk stratification in portal vein thrombosis after splenectomy and its primary prophylaxis with antithrombin III concentrates and danaparoid sodium in liver cirrhosis with portal hypertension

BACKGROUND

Decreased antithrombin III (ATIII) activity and large splenic vein diameter (SVD) are risk factors for portal vein thrombosis (PVT) after splenectomy in liver cirrhosis with portal hypertension. Antithrombin III concentrates can prevent PVT. This study was designed to stratify risks for PVT after splenectomy in cirrhotic patients and to develop prophylactic protocols for PVT.

STUDY DESIGN

In 53 patients (testing cohort), the cutoff level of preoperative ATIII activity (≤60%) was evaluated for administration of ATIII concentrates. Antithrombin III activity and SVD were re-evaluated as criteria for prophylaxis of PVT. In 57 patients (validation cohort), the risk stratification of PVT and prophylactic protocols were validated.

RESULTS

In the testing cohort, 10 (19%) of 53 patients had PVT. Risk level of PVT was stratified and prophylactic protocols were developed. Patients at low risk (ATIII activity ≥70% and SVD <10 mm) were not treated; those at high risk (ATIII activity <70% or SVD ≥10 mm) received ATIII concentrates (1,500 U/day) for 3 days; and those at highest risk (SVD ≥15 mm) received ATIII concentrates for 3 days, followed by danaparoid sodium (2,500 U/day) for 14 days and warfarin. In the validation cohort, 0 of 14 low-risk and 2 of 32 high-risk patients had PVT. Although 8 of 11 patients at highest risk had temporary PVT, it disappeared within 3 months postoperatively. Finally, only 2 (3.5%) of 57 patients had PVT.

CONCLUSIONS

Risk stratification of PVT after splenectomy and prophylaxis with ATIII concentrates and danaparoid sodium dramatically reduced the incidence of PVT.

Deep vein thrombosis and pulmonary embolism in cirrhotic patients: Systematic review

Patients with liver cirrhosis were traditionally believed to be protected against development of blood clots. Lately, studies have shown that these patients may probably be at an increased risk of venous thrombotic complications. Although the hemostatic changes in the chronic liver disease patients and the factors that may predict bleeding vs thrombotic complications remains an area of active research, it is believed that the coagulation cascade is delicately balanced in these patients because of parallel reduced hepatic synthesis of pro and anticoagulant factors. Thrombotic state in cirrhotic patients is responsible for not only portal or non-portal thrombosis [deep vein thrombosis (DVT) and pulmonary embolism (PE)]; it has also been associated with progression of liver fibrosis. The use of anticoagulants in cirrhosis patients is a challenging, and often a scary situation. This review summarizes the current literature on the prevalence of venous thrombosis (DVT and PE), risk factors and safety of prophylactic and therapeutic anticoagulation in patients with chronic liver disease.

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.