Randomized controlled trial of rivaroxaban versus warfarin in the management of acute non-neoplastic portal vein thrombosis

Cerebral and Splanchnic Vein Thrombosis: Advances, Challenges, and Unanswered Questions

Cerebral vein thrombosis (CVT) and splanchnic vein thrombosis (SVT) are two manifestations of venous thromboembolism (VTE) at unusual sites. They have an incidence at least 25-50 times lower than usual site VTE, but represent true clinical challenges. Recent evidence on the epidemiology, risk factors, prognosis, and treatment of CVT and SVT has been published in the last two decades, thus contributing to a better understanding of these diseases. The improvement in imaging techniques and a higher degree of clinical suspicion may have led to the observed increased frequency, whereas a better knowledge of provoking mechanisms could have contributed to reducing the proportion of events classified as unprovoked or idiopathic (13%-21% of CVT, 15%-27% of SVT). Few small randomized clinical trials and a number of observational studies, although hampered by heterogeneous therapeutic approaches, shed light on the safety and effectiveness of anticoagulant therapy in these populations. However, there are still some grey areas that warrant future research. In this narrative review, we discuss recent advances and therapeutic challenges in CVT and SVT.

Acute superior mesenteric venous thrombosis results in high rates of readmission and morbidity

OBJECTIVE

Superior mesenteric venous thrombosis (MVT) is a poorly understood clinical entity, and as such, outcomes are poorly described. This study aimed to identify predictors of bowel ischemia after MVT and to compare outcomes for patients treated medically (group 1) with those for patients treated with bowel resection (group 2).

METHODS

This was a retrospective, single-institution study capturing all patients diagnosed with symptomatic acute MVT on computed tomography imaging from 2008 to 2018. Demographics, comorbidities, imaging, laboratory values, and treatment were included. Predictors of bowel resection were analyzed by univariate and multivariate statistics. Outcomes including mortality, readmissions for abdominal pain, and chronic mesenteric venous congestion were compared using χ² test.

RESULTS

There were 121 patients included in the study; 98 patients were treated medically (group 1), 19 patients were treated with bowel resection (group 2), and 4 patients were treated with endovascular recanalization (group 3). Group 1 and group 2 were compared directly. Patients requiring bowel resection tended to have higher body mass index (P = .051) and a hypercoagulable disorder (P = .003). Patients who required bowel resection were more likely to present with lactic acidosis (P < .001) and leukocytosis (P < .001) with bowel wall thickening on scan (P < .001). On multivariable analysis, a genetic thrombophilia was a strong predictor of bowel ischemia (odds ratio, 3.81; 95% confidence interval, 1.12-12.37). One-year mortality and readmission rates did not differ between groups. However, readmission rates for abdominal pain were high for both groups (group 1, 44.90%; group 2, 57.89%; P = .317), and a significant proportion of patients exhibited chronic mesenteric venous congestion on repeated scan (group 1, 42.86%; group 2, 47.37%; P = .104).

CONCLUSIONS

A genetic hypercoagulable disorder is a predictor of bowel ischemia due to MVT. Regardless of treatment, outcomes after MVT are morbid, with high rates of readmission for abdominal pain. An alternative approach to treat these patients is needed, given the poor outcomes with current strategies.

Recent developments in the field of vascular liver diseases

Knowledge in the field of vascular liver disease is continuously expanding. The present update will discuss recent data on i) the Abernethy malformation in adults; ii) portal vein thrombosis in cirrhosis; iii) advancing expertise in recanalization of the portal vein and iv) experience in using direct oral anticoagulants in the field of vascular liver disease.

Splanchnic Vein Thrombosis: Current Perspectives

Splanchnic vein thrombosis (SVT) including portal, mesenteric, splenic vein thrombosis and the Budd-Chiari syndrome, is a manifestation of unusual site venous thromboembolism. SVT presents with a lower incidence than deep vein thrombosis of the lower limbs and pulmonary embolism, with portal vein thrombosis and Budd-Chiari syndrome being respectively the most and the least common presentations of SVT. SVT is classified as provoked if secondary to a local or systemic risk factor, or unprovoked if the causative trigger cannot be identified. Diagnostic evaluation is often affected by the lack of specificity of clinical manifestations: the presence of one or more risk factors in a patient with a high clinical suspicion may suggest the execution of diagnostic tests. Doppler ultrasonography represents the first line diagnostic tool because of its accuracy and wide availability. Further investigations, such as computed tomography and magnetic resonance angiography, should be executed in case of suspected thrombosis of the mesenteric veins, suspicion of SVT-related complications, or to complete information after Doppler ultrasonography. Once SVT diagnosis is established, a careful patient evaluation should be performed in order to assess the risks and benefits of the anticoagulant therapy and to drive the optimal treatment intensity. Due to the low quality and large heterogeneity of published data, guidance documents and expert opinion could direct therapeutic decision, suggesting which patients to treat, which anticoagulant to use and the duration of treatment.

Safety of direct oral anticoagulants in patients with cirrhosis: a systematic review and meta-analysis

INTRODUCTION

Direct oral anticoagulants (DOACs) are effective treatment for venous thromboembolism. However, safety data in patients with cirrhosis are limited. We conducted a systematic review and meta-analysis to evaluate the safety of DOACs compared with warfarin or low-molecular weight heparin in patients with cirrhosis.

METHODS

A systematic literature search was performed using MEDLINE and EMBASE from inception up to June 2018. We included prospective and retrospective studies involving adults ≥18 years with cirrhosis in whom anticoagulants were indicated for any indications. Primary outcome was all-cause bleeding events. Secondary outcome was major bleeding. Pooled risk ratio, pooled odd ratios and 95% confidence intervals (CIs) were calculated using random-effects model.

RESULTS

Five studies with a total of 447 patients were included in the analysis. When compared with controls, the use of DOACs in cirrhotic patients did not show a significant difference in all-cause bleeding (risk ratio 0.72; 95% CI, 0.32-1.63). There was also no significant difference in major bleeding between both groups (odd ratio 0.46; 95% CI, 0.10-2.09).

CONCLUSIONS

Our study demonstrates that, compared to those who were treated with traditional anticoagulants, cirrhotic patients who were treated with DOACs had no significant increase risk of all-cause bleeding and major bleeding.

Anticoagulation in the cirrhotic patient

In the past, patients with liver cirrhosis were thought to be prone to increased bleeding risk. However, those with compensated liver cirrhosis actually have normal coagulative balance, which can become altered when liver function worsens, or infection, bleeding, or acute kidney insufficiency occur. When this happens, it is now recognized that patients with liver cirrhosis are at higher risk of thrombotic rather than haemorrhagic complications. Anticoagulation plays a favourable role both when used therapeutically or prophylactically. Successful anticoagulation is associated with a lower rate of decompensation and with improved survival. To date, treatment has involved the use of low molecular weight heparins and vitamin K antagonists. Preliminary data suggest that novel non-vitamin K antagonist oral anticoagulants can be used safely in patients with liver cirrhosis.

AGA Clinical Practice Update: Coagulation in Cirrhosis

DESCRIPTION

This expert review was commissioned and approved by the AGA Institute Clinical Practice Updates Committee and the AGA Governing Board to provide timely guidance on a topic of high clinical importance to the AGA membership. The intent is to evaluate the current data on mechanism of altered coagulation in patients with cirrhosis, provide guidance on the use of currently available testing of the coagulation cascade, and help practitioners use anticoagulation and pro-coagulants appropriately in patients with cirrhosis.

METHODS

This review is framed around the best practice points, which were derived from the most impactful publications in the area of coagulation in cirrhosis and agreed to by all authors. BEST PRACTICE ADVICE 1: Global tests of clot formation, such as rotational thromboelastometry, thromboelastography, sonorheometry, and thrombin generation, may eventually have a role in the evaluation of clotting in patients with cirrhosis, but currently lack validated target levels. BEST PRACTICE ADVICE 2: In general, clinicians should not routinely correct thrombocytopenia and coagulopathy before low-risk therapeutic paracentesis, thoracentesis, and routine upper endoscopy for variceal ligation in patients with hepatic synthetic dysfunction-induced coagulation abnormalities. BEST PRACTICE ADVICE 3: Blood products should be used sparingly because they increase portal pressure and carry a risk of transfusion-associated circulatory overload, transfusion-related acute lung injury, infection transmission, alloimmunization, and/or transfusion reactions. BEST PRACTICE ADVICE 4: The following transfusion thresholds for management of active bleeding or high-risk procedures may optimize clot formation in advanced liver disease: hematocrit ≥25%, platelet count >50,000, and fibrinogen >120 mg/dL. Commonly utilized thresholds for international normalized ratio correction are not supported by evidence. BEST PRACTICE ADVICE 5: Thrombopoietin agonists are a good alternative to platelet transfusion, but require time (about 10 days) to elevate platelet levels. BEST PRACTICE ADVICE 6: The large volume of fresh frozen plasma required to reach an arbitrary international normalized ratio target, limitations of the usual target, minimal effect on thrombin generation, and adverse effects on portal pressure limit the utility of this agent significantly. BEST PRACTICE ADVICE 7: The 4-factor prothrombin complex concentrate contains both pro- and anticoagulant factors that offer an attractive low-volume therapeutic to rebalance a disturbed hemostatic system. However, dosage is, in part, based on international normalized ratio, which is problematic in cirrhosis, and published experience in liver disease is limited. BEST PRACTICE ADVICE 8: Anti-fibrinolytic therapy may be considered in patients with persistent bleeding from mucosal oozing or puncture wound bleeding consistent with impaired clot integrity. Both ε-aminocaproic acid and tranexamic acid inhibit clot dissolution. Neither is believed to generate a hypercoagulable state, although both may exacerbate pre-existing thrombi. BEST PRACTICE ADVICE 9: Desmopressin releases von Willebrand factor as its primary hemostatic mechanism. As this factor is usually elevated in cirrhosis, the agent lacks a sound evidence-based foundation, but may be useful in patients with concomitant renal failure. BEST PRACTICE ADVICE 10: Systemic heparin infusion is recommended for symptomatic deep vein thrombosis and portal and mesenteric vein thrombosis, but there are unresolved issues regarding monitoring with both the anti-Xa assay and the partial thromboplastin time due to cirrhosis-related antithrombin deficiency (heparin cofactor). BEST PRACTICE ADVICE 11: Treatment of incidental portal and mesenteric vein thrombosis depends on estimated impact on transplantation surgical complexity vs risks of bleeding and falls. Therapy with low-molecular-weight heparin, vitamin K antagonists, and direct-acting anticoagulants improve portal vein repermeation vs observation alone. BEST PRACTICE ADVICE 12: Direct-acting anticoagulants, such as the factor Xa and thrombin inhibitors, are relatively safe and effective in stable cirrhotic patients, but are in need of further study in patients with more advanced liver disease.

Portal vein thrombosis in cirrhotic patients - it is always the small pieces that make the big picture

Portal vein thrombosis (PVT) is a frequent and serious complication in patients with liver cirrhosis (LC). Recently, a new classification of PVT was proposed, although the functional component was not completed included. The status of liver disease (compensated/decompensated) should be added to this classification. Reduced portal flow velocity and the acquired hypercoagulable status associated with LC are the main risk factors for PVT development, although endothelial dysfunction may play an important role that needs to be further evaluated. The European Association for the Study of the Liver and the American Association for the Study of Liver Disease recommend that the anticoagulant treatment should be consider in cirrhotic patients with PVT. Low molecular weight heparin and vitamin K antagonists proved their efficacy and relatively safety in PVT treatment, although in addition to recanalization rates, more complex end-points such as mortality and decompensation rate should be evaluated. The new oral anticoagulant therapies offers the advantage of oral administration in the absence of laboratory monitoring, however, there are a few reports regarding their use in cirrhotic patients, most of them referring to compensated isolated cases. Transjugular intrahepatic portosystemic shunt could be an alternative if thrombosis progresses despite anticoagulatant therapy and/or when PVT is associated with portal hypertension complications. The aim of this editorial is to discuss the different aspects of pathophysiology, clinical relevance, diagnosis and management of PVT in patients with LC.