Comparative study of coagulation and thrombin generation in the portal and jugular plasma of patients with cirrhosis

Efficacy and Safety of Direct Oral Anticoagulants Compared to Warfarin in Patients with Cirrhosis and Splanchnic Vein Thrombosis

OBJECTIVE

The incidence of splanchnic vein thrombosis (SVT) is reported to be <25 times lower than that of deep vein thrombosis and pulmonary emboli, which occur in 70 to 270/100,000 cases in the general population. Current guidelines recommend initial treatment with therapeutic low-molecular-weight heparin followed by a transition to a vitamin K antagonist (VKA) or a direct oral anticoagulant (DOAC) in patients with cirrhosis who develop SVT without severe liver dysfunction. This, however, is based on observational data. This study aimed to evaluate the efficacy and safety of anticoagulant therapy in patients with cirrhosis who present with SVT and receive either a DOAC or a VKA.

METHODS

This multicenter retrospective cohort study was conducted from December 2021 to November 2022. Patients between the ages of 18 and 75 years with cirrhosis and acute SVT who received either a VKA or a DOAC between July 2019 and July 2021 were eligible for inclusion. The primary outcome was the efficacy of treatment, defined as a new thrombotic event. The secondary outcome was the safety of treatment, defined as the development of major bleeding. Readmission data were followed up at 6 and 10 months. Bivariate analysis was conducted to assess the relationship between the medication groups and each outcome and summarized as odds ratios (ORs) with 95% confidence intervals (CIs). Statistical significance was set at 5% for all of the comparisons.

RESULTS

A total of 80 patients from 50 hospitals were included in this study. Sixty-one patients (59.02% male) received DOACs and 19 (57.89% male) received a VKA. Of the patients who received DOACs, 41 (67.21%) received apixaban, one (1.64%) received dabigatran, and 19 (31.15%) received rivaroxaban. The results from the bivariate analysis revealed no significant differences between DOACs and warfarin for both the efficacy (OR 1.46, 95% CI 0.44-4.84, P = 0.53) and safety outcomes (OR 1.03, 95% CI 0.04-26.43, P = 1) at 10 months.

CONCLUSIONS

The use of DOACs in patients with cirrhosis who present with SVT may be efficacious and safe compared with warfarin. The findings from our study may inform power analyses for well-conducted randomized trials to confirm these findings.

Portal vein thrombosis: diagnosis, management, and endpoints for future clinical studies

Portal vein thrombosis (PVT) refers to the development of a non-malignant obstruction of the portal vein, its branches, its radicles, or a combination. This Review first provides a comprehensive overview of all aspects of PVT, namely the specifics of the portal venous system, the risk factors for PVT, the pathophysiology of portal hypertension in PVT, the interest in non-invasive tests, as well as therapeutic approaches including the effect of treating risk factors for PVT or cause of cirrhosis, anticoagulation, portal vein recanalisation by interventional radiology, and prevention and management of variceal bleeding in patients with PVT. Specific issues are also addressed including portal cholangiopathy, mesenteric ischaemia and intestinal necrosis, quality of life, fertility, contraception and pregnancy, and PVT in children. This Review will then present endpoints for future clinical studies in PVT, both in patients with and without cirrhosis, agreed by a large panel of experts through a Delphi consensus process. These endpoints include classification of portal vein thrombus extension, classification of PVT evolution, timing of assessment of PVT, and global endpoints for studies on PVT including clinical outcomes. These endpoints will help homogenise studies on PVT and thus facilitate reporting, comparison between studies, and validation of future studies and trials on PVT.

Intraindividual variability over time of thrombin generation in patients with cirrhosis

BACKGROUND

Patients with cirrhosis are at high risk of thrombotic events, including portal vein thrombosis and venous thromboembolism. In such patients, hypercoagulability is not detected by conventional coagulation tests, but only by the thrombin generation assay (TGA) that integrates the role of pro- and anticoagulant factors. However, TGA use to predict clinical events depends on thrombin generation variability over time.

OBJECTIVES

The aim of this study was to compare TGA intraindividual variability over time in patients with cirrhosis and in healthy controls.

METHODS

Blood samples were prospectively collected from 34 healthy controls and 52 patients with cirrhosis at week 0 (inclusion), 6, and 12. TGA was performed with the calibrated automated thrombogram method, tissue factor (5 pM), phospholipids, and with and without thrombomodulin (4 nM) or activated protein C (1 nM).

RESULTS

When TGA was performed with thrombomodulin, endogenous thrombin potential in patients with cirrhosis was higher compared with controls and increased with cirrhosis severity. Stability over time of all thrombin generation parameters was excellent in healthy controls, good in Child-Turcotte-Pugh (CTP)-A patients, and poor in CTP-B/C patients (severe cirrhosis). In CTP-B/C patients, the phenotype was more variable because one-third of patients switched to normal or hypercoagulability during the 3-month follow-up.

CONCLUSION

A study with longer monitoring is needed to correlate the hypercoagulable phenotype of patients with cirrhosis with the occurrence of thrombotic events.

Portal Vein Thrombosis in the Setting of Cirrhosis: A Comprehensive Review

Portal vein thrombosis constitutes the most common thrombotic event in patients with cirrhosis, with increased rates in the setting of advanced liver disease. Despite being a well-known complication of cirrhosis, the contribution of portal vein thrombosis to hepatic decompensation and overall mortality is still a matter of debate. The incorporation of direct oral anticoagulants and new radiological techniques for portal vein recanalization have expanded our therapeutic arsenal. However, the lack of large prospective observational studies and randomized trials explain the heterogenous diagnostic and therapeutic recommendations of current guidelines. This article seeks to make a comprehensive review of the pathophysiology, clinical features, diagnosis, and treatment of portal vein thrombosis in patients with cirrhosis.

The Pathophysiology of Portal Vein Thrombosis in Cirrhosis: Getting Deeper into Virchow's Triad

Portal vein thrombosis (PVT) is a common complication among patients with cirrhosis. However, its pathophysiology is not well established and there are currently very few predictive factors, none of which are actually useful, from a clinical perspective. The contribution of each of the vertices of Virchow’s triad, e.g., blood hypercoagulability, blood flow, and portal vein endothelial damage in the development of PVT is not clear. In this review, we aim to recapitulate the latest studies on the field of PVT development in order to understand its mechanisms and discuss some of the future directions in the study of this important complication of cirrhosis.

Von Willebrand and Factor VIII Portosystemic Circulation Gradient in Cirrhosis: Implications for Portal Vein Thrombosis

Portal vein thrombosis seems to be dependent on local hypercoagulation and venous stasis; data regarding endothelial damage are lacking.

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

BACKGROUND

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

OBJECTIVE

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

PATIENTS/METHODS

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

RESULTS

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

CONCLUSION

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

Deciphering the coagulation profile through the dynamics of thrombin activity

Thrombosis has proven to be extremely difficult to predict. Measuring the generation of thrombin is a very sensitive method to detect changes in the hemostatic system. We developed a method based on the generation of thrombin to further fingerprint hemostasis, which we have named thrombin dynamics. Via this method we are able to exactly measure the prothrombin conversion and thrombin inactivation, and any change in the coagulation cascade will be reflected in these two processes. In the current study we analyzed the importance of the members of the prothrombin complex on the dynamics of thrombin activation and inactivation. We show that prothrombin conversion is predominantly influenced by factor X and antithrombin, which will provide essential insights in complex thrombosis-related diseases, such as liver cirrhosis and kidney failure.

Hemostatic Alterations in Patients With Cirrhosis: From Primary Hemostasis to Fibrinolysis

In the setting of liver cirrhosis (LC), profound hemostatic changes occur, which affect primary hemostasis, coagulation, and fibrinolysis. They involve prohemorrhagic and prothrombotic alterations at each of these steps. Patients with cirrhosis exhibit multifactorial thrombocytopenia and in vitro thrombocytopathy, counterbalanced by increased von Willebrand factor. The resultant shift is difficult to assess, but overall these changes probably result in a rebalanced primary hemostasis. Concerning coagulation, the reduced activity of coagulation factors is counterbalanced by an increase in factor VIII (produced by liver sinusoidal endothelial cells), a decrease of the natural anticoagulants, and complex changes, including changes in circulating microparticles, cell-free DNA, and neutrophil extracellular traps. Overall, these alterations result in a procoagulant state. As for fibrinolysis, increased tissue-type and urokinase-type plasminogen activators, a relatively decreased plasminogen activator inhibitor 1, and decreased levels of thrombin-activatable fibrinolysis inhibitor and α2-antiplasmin are counterbalanced by decreased plasminogen and a decreased fibrin clot permeability. Whether and how these changes shift fibrinolysis remains to be determined. Overall, the current consensus is that in patients with cirrhosis, the hemostasis is shifted toward a procoagulant state. We review the published evidence for the concept of LC as a prothrombotic state, discuss discordant data, and highlight the impact of the underlying cause of LC on the resultant imbalance.

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

BACKGROUND AND AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

D-dimer plasmatic levels as a marker for diagnosis and prognosis of hepatocellular carcinoma patients with portal vein thrombosis

Purpose

Portal vein thrombosis (PVT) is one of the severe complications of hepatocellular carcinoma (HCC). PVT deteriorates the liver, and its dysfunction increases the risk of bleeding, influencing the prognosis of patients with liver cirrhosis and HCC. The aim of our study was to investigate whether D-dimer testing could be a sensitive marker for the diagnosis and prognosis of HCC patients with PVT.

Patients and methods

Between June 2010 and December 2015, 118 HCC patients were admitted to Cannizzaro Hospital, Catania, and 50 controls were recruited from their relatives for health examinations. All enrolled patients were diagnosed and pathologically confirmed as having HCC. D-dimer was measured with an enzyme-linked immunosorbent assay using 2 monoclonal antibodies against nonoverlapping determinants of D-dimer.

Results

D-dimer levels in HCC patients with PVT were significantly higher vs HCC patients without PVT, P<0.002, and vs controls, P<0.001.

Conclusion

Plasma D-dimer is a sensitive marker of fibrin turnover and allows for the recognition of activated coagulation which may be manifested in HCC with PVT.

Increased factor VIII plays a significant role in plasma hypercoagulability phenotype of patients with cirrhosis

Essentials The role of increased factor VIII in cirrhosis-induced hypercoagulability has never been demonstrated. Factor VIII and protein C effects were characterized by thrombin generation with thrombomodulin. Factor VIII elevation plays a significant role in cirrhosis-induced plasma hypercoagulability. Only protein C and factor VIII normalization led to thrombin generation similar to controls.

SUMMARY

Background In cirrhosis, thrombin generation (TG) studied in the presence of thrombomodulin (TM) indicates plasma hypercoagulability. Although the role of protein C (PC) deficiency has been investigated, the influence of an increase in the factor VIII level has never been addressed. Objectives We investigated the roles of high FVIII and low PC levels in increased TG in the presence of TM. Methods Blood samples were prospectively collected from 35 healthy controls and 93 patients with cirrhosis (Child-Turcotte-Pugh [CTP]-A, n = 61; CTP-B, n = 19; and CTP-C, n = 13) and FVIII levels > 150% (n = 48) and/or PC levels < 70% (n = 88). TG was performed with tissue factor (5 pm), phospholipids, and TM (4 nm). FVIII and PC levels were normalized by adding an inhibitory anti-FVIII antibody and exogenous PC, respectively. Results The endogenous thrombin potential (ETP) in the presence of TM was higher in patients than in controls. After FVIII normalization, the ETP (median) decreased from 929 nm min to 621 nm min (CTP-A), 1122 nm min to 1082 nm min (CTP-B), and 1221 nm min to 1143 nm min (CTP-C); after PC normalization, it decreased from 776 nm min to 566 nm min (CTP-A), 1120 nm min to 790 nm min (CTP-B), and 995 nm min to 790 nm min (CTP-C). The ETP was reduced by 17% and 30%, respectively, but normal TG was not restored. When both FVIII and PC levels were normalized, the ETP decreased from 929 nm min to 340 nm min (CTP-A), 1122 nm min to 506 nm min (CTP-B), and 1226 nm min to 586 nm min (CTP-C), becoming similar to control levels. Conclusion Cirrhosis-induced plasma hypercoagulability, as demonstrated in these experimental conditions, can be partly explained by opposite changes in two factors: PC level (decrease) and FVIII level (increase).

Portal vein thrombosis in cirrhosis: diagnosis, natural history, and therapeutic challenges

Portal vein thrombosis (PVT) is a frequent complication in cirrhosis and its prevalence increases with disease severity. Several factors are involved in the development and progression of PVT. The challenge for the management of PVT is the precise evaluation of the bleeding risk as opposed to life-threatening extension of thrombosis. Nevertheless, the impact on the progression and outcome of liver disease is unclear. A critical evaluation of the available data discloses that treating PVT in cirrhotics is safe and effective. However, there are open issues, such as which anticoagulant could represent a safer therapeutic option, and when and for how long this treatment should be administered to cirrhotic patients with PVT.

Platelet Activation Assessed by Glycoprotein VI/Platelet Ratio Is Associated With Portal Vein Thrombosis After Hepatectomy and Splenectomy in Patients With Liver Cirrhosis

Portal vein thrombosis (PVT) is a serious complication after hepatobiliary-pancreatic surgery. Portal vein thrombosis often develops in patients with liver cirrhosis (LC) postoperatively, although they have low platelet counts. Platelet activation is one of the causes of thrombosis formation, and soluble form of glycoprotein VI (sGPVI) has received attention as a platelet activation marker. We had prospectively enrolled the 81 consecutive patients who underwent splenectomy (Sx) and/or hepatectomy: these patients were divided as Sx (n = 38) and hepatectomy (Hx, n = 46) groups. The 3 patients who underwent both procedures were added to both groups. Each group was subdivided into patients with non-LC and LC: non-LC-Sx (n = 22) and LC-Sx (n = 16), non-LC-Hx (n = 40) and LC-Hx (n = 6). The presence of PVT was diagnosed by using enhanced computed tomography (CT) scan. Platelet counts were significantly lower in LC-Sx than in non-LC-Sx, and incidence of PVT was significantly higher in LC-Sx than in non-LC-Sx (68.8% vs 31.8%, P = .024). Soluble form of glycoprotein VI /platelet ratios on preoperative day and postoperative day 1 were significantly higher in LC-Sx than in non-LC-Sx. Incidence of PVT was significantly higher in LC-Hx than in non-LC-Hx (50.0% vs 7.5%, P < .01). Soluble form of glycoprotein VI /platelet ratios were significantly higher in LC-Hx before and after Hx, compared to non-LC-Hx. Patients with LC stay in hypercoagulable state together with platelet activation before and after surgery. Under this circumstance, alteration of portal venous blood flow after Sx or Hx is likely to cause PVT in patients with LC.

The anticoagulant rivaroxaban lowers portal hypertension in cirrhotic rats mainly by deactivating hepatic stellate cells

In cirrhosis, increased intrahepatic vascular resistance (IHVR) is the primary factor for portal hypertension (PH) development. Hepatic stellate cells (HSCs) play a major role increasing IHVR because, when activated, they are contractile and promote fibrogenesis. Protease-activated receptors (PARs) can activate HSCs through thrombin and factor Xa, which are known PAR agonists, and cause microthrombosis in liver microcirculation. This study investigates the effects of the oral anticoagulant, rivaroxaban (RVXB), a direct antifactor Xa, on HSC phenotype, liver fibrosis (LF), liver microthrombosis, and PH in cirrhotic rats. Hepatic and systemic hemodynamic, nitric oxide (NO) bioavailability, LF, HSC activation, and microthrombosis were evaluated in CCl₄ and thioacetamide-cirrhotic rats treated with RVXB (20 mg/kg/day) or its vehicle for 2 weeks. RVXB significantly decreased portal pressure (PP) in both models of cirrhosis without changes in portal blood flow, suggesting a reduction in IHVR. RVXB reduced oxidative stress, improved NO bioavailability, and ameliorated endothelial dysfunction. Rivaroxaban deactivated HSC, with decreased alpha-smooth muscle actin and mRNA expression of other HSC activation markers. Despite this marked improvement in HSC phenotype, no significant changes in LF were identified. RVXB markedly reduced fibrin deposition, suggesting reduced intrahepatic microthrombosis.

CONCLUSION

RVXB decreases PP in two rat models of cirrhosis. This effect is mostly associated with decreased IHVR, enhanced NO bioavailability, HSC deactivation, and reduced intrahepatic microthrombosis. Our findings suggest that RVXB deserves further evaluation as a potential treatment for cirrhotic PH. (Hepatology 2017;65:2031-2044).

Decreased prothrombin conversion and reduced thrombin inactivation explain rebalanced thrombin generation in liver cirrhosis

Impaired coagulation factor synthesis in cirrhosis causes a reduction of most pro- and anticoagulant factors. Cirrhosis patients show no clear bleeding or thrombotic phenotype, although they are at risk for both types of hemostatic event. Thrombin generation (TG) is a global coagulation test and its outcome depends on underlying pro- and anticoagulant processes (prothrombin conversion and thrombin inactivation). We quantified the prothrombin conversion and thrombin inactivation during TG in 30 healthy subjects and 52 Child-Pugh (CP-) A, 15 CP-B and 6 CP-C cirrhosis patients to test the hypothesis that coagulation is rebalanced in liver cirrhosis patients. Both prothrombin conversion and thrombin inactivation are reduced in cirrhosis patients. The effect on pro- and anticoagulant processes partially cancel each other out and as a result TG is comparable at 5 pM tissue factor between healthy subjects and patients. This supports the hypothesis of rebalanced hemostasis, as TG in cirrhosis patients remains within the normal range, despite large changes in prothrombin conversion and thrombin inactivation. Nevertheless, in silico analysis shows that normalization of either prothrombin conversion or thrombin inactivation to physiological levels, by for example the administration of prothrombin complex concentrates would cause an elevation of TG, whereas the normalization of both simultaneously maintains a balanced TG. Therefore, cirrhosis patients might require adapted hemostatic treatment.

Plasma hypercoagulability in the presence of thrombomodulin but not of activated protein C in patients with cirrhosis

BACKGROUND AND AIMS

Cirrhosis significantly changes all hemostasis steps. Recent studies suggest that cirrhosis is associated with a coagulopathy leading to a hypercoagulable state. The underlying mechanisms are not fully understood, but protein C deficiency is probably a major determinant of this phenotype. The aim of this study was to compare the results of thrombin generation assays performed with addition of thrombomodulin or activated protein C to assess the effect of by-passing the protein C activation step in cirrhotic patients and healthy controls.

METHODS

Fifty-eight patients with cirrhosis and 26 healthy controls were prospectively included in this study. Thrombin generation was determined in platelet-poor plasma using 5 pM of tissue factor and 4 nM of phospholipids, without and with external addition of 1 nM thrombomodulin or 4 nM activated protein C. All results were normalized with the values of a pool of normal plasma samples to limit inter-plate variability.

RESULTS

When thrombin generation assays were performed in the presence of thrombomodulin, endogenous thrombin potential (ETP) and ETP with/ETP without TM ratio were significantly higher in cirrhotic patients than in healthy controls (P < 0.0001). Moreover, these values progressively increased with cirrhosis severity. When thrombin generation assays were performed with activated protein C, all thrombin generation parameters were comparable between healthy controls and cirrhotic patients, despite an acquired protein S deficiency.

CONCLUSION

In the presence of activated protein C, no hypercoagulability was observed, adding to the current evidence that acquired protein C deficiency plays a key role in the coagulation imbalance.

Thromboelastometry hypercoagulable profiles and portal vein thrombosis in cirrhotic patients with hepatocellular carcinoma

BACKGROUND

Cirrhotic patients with hepatocellular carcinoma (HCC) exhibit hypercoagulability.

AIM

We investigated whether thromboelastometry can detect hypercoagulability in these patients and the association with portal vein thrombosis (PVT).

METHODS

At baseline, cirrhotic patients with and without HCC underwent thromboelastometry. PVT onset was recorded over a 12-month follow-up period.

RESULTS

Seventy-six patients (41 with and 35 without HCC) were included. Vital tumor volume (VTV) was  >5cm³ in 18 patients. Fibrinogen was higher in HCC patients with VTV>5cm³ as compared to those with VTV≤5cm³ and those without HCC. Mean platelet count was significantly increased in HCC patients compared with non-HCC. At baseline thromboelastometry, HCC patients showed shorter CTF and higher MCF than non-HCC. PVT incidence was 24,4% and 11.4% in patients with (10/41) and without (4/35) HCC, respectively. Among HCC, 50% of PVT occurred in Child A patients. In HCC, FIBTEM MCF>25mm was associated with a 5-fold increased PVT risk [RR: 4.8 (2-11.3); p=0.0001]. Cox multivariate analysis confirmed HCC and increased MCF (FIBTEM) to be independently associated with increased PVT risk.

CONCLUSIONS

Hypercoagulability in HCC which can be detected by thromboelastometry is associated with increased risk of PVT even in Child A patients. The clinical implication of these findings deserves further investigation.

Phosphatidylserine on blood cells and endothelial cells contributes to the hypercoagulable state in cirrhosis

BACKGROUND & AIMS

The mechanism of thrombogenicity in cirrhosis is largely unknown. Our objective was to study the relationship between phosphatidylserine on blood cells and endothelial cells and the hypercoagulable state in cirrhotic patients.

METHODS

Patients with cirrhosis and healthy controls were studied. Lactadherin was used to quantify phosphatidylserine exposure on blood cells and endothelial cells. Procoagulant activity of cells was evaluated using clotting time and purified coagulation complex assays. Fibrin production was determined by turbidity. Phosphatidylserine exposure, fibrin strands and FVa/Xa binding on cells were observed using confocal microscopy.

RESULTS

Our study showed that phosphatidylserine exposure on erythrocytes, platelets and leucocytes in cirrhotic patients increased progressively with Child-Pugh categories. In addition, we found that endothelial cells treated with cirrhotic serum in vitro exposed more phosphatidylserine than those exposed to healthy serum. The exposed phosphatidylserine supported a shorter coagulation time and increased FXa, thrombin and fibrin formation. Notably, phosphatidylserine⁺ erythrocytes also promoted shorter coagulation times and more fibrin generation in cirrhotic microparticle-depleted plasma, regardless of Child-Pugh categories. Confocal microscopy data showed that the FVa/FXa complex and fibrin fibrils colocalized with phosphatidylserine on endothelial cells. Lactadherin significantly inhibited FXa and thrombin generation and consequently decreased fibrin production in normal or cirrhotic plasma.

CONCLUSIONS

These results lead us to believe that exposed phosphatidylserine on activated or injured erythrocytes, platelets, leucocytes and endothelial cells plays an important role in the hypercoagulable state in cirrhotic patients. Thus, blocking phosphatidylserine binding sites might be a new therapeutic target for preventing thrombosis.

Hyperhomocysteinemia and MTHFR C677T polymorphism in patients with portal vein thrombosis complicating liver cirrhosis

BACKGROUND

Portal vein thrombosis (PVT) is serious complication of liver cirrhosis (LC), especially in the presence of hepatocellular carcinoma (HCC). The liver plays a key role in homocysteine (Hcy) metabolism: mild hyperhomocysteinemia (HHcy) has been described in LC. HHcy is a risk factor for deep vein thrombosis. Methylen-tetrahydrofolate-reductase (MTHFR) C677T polymorphism is the commonest determinant of mild HHcy and has been involved also in cancer development.

AIM

To investigate a possible relation between HHcy, MTHFR status, HCC and PVT in patients affected by LC.

MATERIALS AND METHODS

100 patients affected by LC, 38 with (PVT group, 24 with HCC) and 62 without PVT (LC group, 14 with HCC) sex-, age-, liver disease stage and etiology-matched were assessed for thrombophilia, smoking status, plasma Hcy, MTHFRC677T polymorphism and homocysteine-related vitamin status.

RESULTS

A higher prevalence of HCC, HHcy and MTHFR TT status was observed in PVT group. No significant difference in vitamin status was observed between groups. Patients with HCC showed significantly higher plasma Hcy and higher prevalence of HHcy than patients without HCC. They had also higher prevalence of MTHFR TT status. In patients with TT status (n=11) and HCC, 10 had HHcy e 9 had PVT.

CONCLUSIONS

Mild HHcy is associated to LC may have a role in PVT development and assessment of plasma Hcy may be suggested in patients with LC (especially if complicated by HCC). Association between HCC and MTHFR TT status is intriguing, due the postulated role for this polymorphism in cancer: it may represent a possible link between HCC and PVT.

Thrombin generation measured as thrombin-antithrombin complexes predicts clinical outcomes in patients with cirrhosis

AIM

Hypercoagulability has been detected in patients with cirrhosis yet its clinical significance remains unclear. We investigated the association of hypercoagulability with clinical outcomes in patients with cirrhosis.

METHODS

Thrombin-antithrombin (TAT) complexes as thrombin generation (TG) marker, D-dimer, antithrombin (AT), protein C, protein S, international normalized ratio (INR), activated partial thromboplastin time, fibrinogen, Child-Pugh class and Model for End-Stage Liver Disease (MELD) were evaluated. Two different multivariate analyses were performed: one not including MELD (model 1) and one including MELD and excluding INR (model 2).

RESULTS

Eighty-one patients (Child-Pugh class A/B/C: 27/27/27) and 40 healthy subjects were enrolled. Only ΤΑΤ and AT were independently associated with increasing liver disease severity. Increased TAT levels and MELD score were significantly associated with ascites and varices at baseline. Independent predictors of follow-up events were: TAT and MELD score for new-onset ascites; TAT and AT for variceal bleeding (VB); TAT and AT for portal vein thrombosis (PVT); and TAT and MELD for mortality. TAT equaled MELD in mortality prediction at 12 and 18 months. TAT cut-offs at 5.35, 14.6, 13.5 and 9.25 ng/mL identified patient groups with significantly higher probability of new-onset ascites, VB, PVT and mortality, respectively.

CONCLUSION

Increased TG is strongly correlated with portal hypertension-related complications, PVT and mortality in patients with cirrhosis. Measuring TG by TAT could enable risk stratification and institution of preventive strategies to improve clinical outcomes.

Portal vein thrombosis: When to treat and how?

Portal vein thrombosis is an unusual thrombotic condition not frequently seen in the general population; however, it has a higher prevalence in special circumstances such as in liver cirrhosis and hepatic or pancreatic malignancy. It also can be associated with significant morbidity and mortality. In this review, we discuss the current data available to guide therapy in the setting of different associated co-morbidities, hypercoagulable states, and associated thrombosis of the remaining splanchnic circulation. We discuss indications for anticoagulation, including the choice of anticoagulants, as well as the role of conservative 'wait and watch' and invasive therapies, such as thrombolysis, thrombectomy, and transjugular intrahepatic portosystemic shunt.

Endogenous thrombin potential and examination of a further 31 analytes in liver transplant candidates

BACKGROUND

To predict the change in patient status and differentation of the basic diseases, endogenous thrombin potential (ETP), clinical chemistry, and coagulation variables were measured in liver transplant-listed patients with different etiologies.

METHODS

Differences in values of ETP and analytes of 30 control persons and 164 cirrhotic patients were examined by means of binary logistic regression. The relationship between the analytes and ETP parameters were analyzed by means of Spearman correlation. The different etiologies of cirrhosises were studied by factor and discriminant analyses. Binary logistic regression was applied to forecast changes in clinical status. Survival analysis was carried out with the appropriate variable.

RESULTS

International Normalized Ratio and activated partial thromboplastin time values were higher, whereas the area-under-the-curve values were lower in cirrhosis than in healthy subjects. A strong relationship was found only between the peak height and the anti-thrombin III (ATIII) values. In the factor analysis, 3 factors were found, which explained 81.6% of the total variance. Combination of aspartate aminotransferase and ATIII mostly separated the basic disease groups from each other in the discriminant analysis. From 35 variables, the lactate dehydrogenase (LDH) and ATIII have been suited for predicting the change in patient status. Eighty percent of patients with low ATIII and high LDH levels had deterioration of their clinical status.

CONCLUSIONS

Our study demonstrated that the ETP parameters did not provide additional information compared with "conventional" coagulation tests in cirrhosis. On the basis of our study, LDH and ATIII appear to be promising analytes to assess the clinical status of patients with cirrhosis. In our opinion, the classification system of liver transplant-listed patients can be improved with their use.

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.