Safety and efficacy of anticoagulation therapy with low molecular weight heparin for portal vein thrombosis in patients with liver cirrhosis

Role of anticoagulant therapy in liver disease

Anticoagulant therapy is a cornerstone in the treatment of different liver diseases. In Budd-Chiari syndrome (BCS), survival rates have increased considerably since the introduction of a treatment strategy in which anticoagulation is the treatment of first choice. In all patients diagnosed with acute portal vein thrombosis (PVT), anticoagulant therapy for at least 3 months is indicated. Anticoagulation should also be considered in patients with chronic PVT and a concurrent prothrombotic risk factor. Current evidence suggests that patients with PVT in cirrhosis will benefit from treatment with anticoagulation as well. In severe chronic liver disease the levels of both pro- and anticoagulant factors are decreased, resetting the coagulant balance in an individual patient and making it more prone to deviate to a hypo- or hypercoagulable state. An increased activity of the coagulation cascade is not solely a feature of chronic liver disease; it influences the development of liver fibrosis as well. Several studies in animals and humans have shown that anticoagulation could prevent or improve fibrogenesis and even disease progression in cirrhosis. Anticoagulation is therefore a promising antifibrotic treatment modality.

Venous thromboembolism in cirrhosis: a review of the literature

Although hemorrhage has traditionally been regarded as the most significant hemostatic complication of liver disease, there is increasing recognition that hypercoagulability is a prominent aspect of cirrhosis. Identifying markers of coagulability and monitoring anticoagulation therapy in the setting of cirrhosis is problematic. The bleeding risk of venous thromboembolism (VTE) prophylaxis and treatment in patients with chronic liver disease is unclear and there are currently no recommendations to guide practice in this regard. In the present report, the mechanism of coagulation disturbance in chronic liver disease is reviewed with an examination of the evidence for an increased VTE risk in cirrhosis. Finally, the available evidence is assessed for prophylaxis and therapy of VTE in chronic liver disease, and the role it may play in decreasing clinical decompensation and improving survival.

Management of nonneoplastic portal vein thrombosis in the setting of liver transplantation: a systematic review

BACKGROUND

Nonneoplastic portal vein thrombosis (PVT) is frequent in patients with cirrhosis who undergo liver transplantation (LT); however, data on its impact on outcome and strategies of management are sparse.

METHODS

A systematic review of the literature was performed by analyzing studies that report on PVT in LT recipients and were published between January 1986 and January 2012.

RESULTS

Of 25,753 liver transplants, 2004 were performed in patients with PVT (7.78%), and approximately half presented complete thrombosis. Thrombectomy/thromboendovenectomy was employed in 75% of patients; other techniques included venous graft interposition and portocaval hemitransposition. Overall, the presence of PVT significantly increased 30-day (10.5%) and 1-year (18.8%) post-LT mortality when compared to patients without PVT (7.7% and 15.4%, respectively). However, only complete PVT accounted for this increased mortality. Rethrombosis occurred in up to 13% of patients with complete PVT and in whom no preventative strategies were used, and was associated with increased morbidity and mortality.

CONCLUSIONS

PVT is common in patients with cirrhosis undergoing LT, and it affects survival when it is complete, at least in the short term after transplant. Therefore, screening for this condition is essential, alongside adequate treatment strategies to attempt repermeation of the PV and prevent thrombosis extension.

Portal vein thrombosis: a clinician-oriented and practical review

With advances in modern imaging techniques, portal vein thrombosis (PVT) is being increasingly diagnosed. It has a wide ranging clinical spectrum from being an asymptomatic state to a potentially life-threatening situation. It is not unusual to find it as an incidental finding in the abdominal imagings done for other reasons. It is commonly associated with cirrhosis and abdominal malignancies and also has a strong association with prothrombotic disorders. It is often difficult for the clinicians to decide whether PVT is acute or chronic. This poses great challenges to its management strategies that include anticoagulants, thrombolysis, and surgical options. Timely diagnosis and appropriate management have great bearings on its outcomes of morbidity and mortality. In this clinician-oriented review, we have provided a concise review of clinical aspects of PVT and discussed various management strategies while addressing the common questions that come to a physician's mind dealing with such a patient.

Splanchnic vein thrombosis and variceal rebleeding in patients with cirrhosis

OBJECTIVES

Splanchnic vein thrombosis (SVT) affects the short-term prognosis of acute variceal bleeding in cirrhotic patients. This study evaluated whether SVT also affects the rebleeding rate of patients included in a program of secondary prophylaxis after variceal bleeding.

PATIENTS AND METHODS

A total of 387 patients with variceal bleeding were included from January 2001 to December 2010. Band ligation was carried out every 3-4 weeks. Follow-up included endoscopy at 1, 3, and every 6 months, Echo-Doppler, and biochemical examination every 6 months. From 2005, patients with SVT received anticoagulation with enoxaparin 200 UI/kg/day for at least 6 months. The therapy was started after variceal eradication.

RESULTS

SVT was diagnosed in 41 patients at variceal bleeding, in eight before and in 18 patients during the follow-up. Variceal eradication was achieved in 89.2 and 86.6% in no-SVT and SVT patients. Rebleeding occurred in 9.5 and 11.9% of no-SVT and SVT patients at 12 months. Varices relapsed more frequently in SVT than in no-SVT patients (25.4 vs. 14.67%, P=0.03). The rates of variceal rebleeding and relapse were similar in patients who received or did not receive anticoagulation, but mortality was significantly lower in patients who received anticoagulation.

CONCLUSION

SVT favors the relapse of esophageal varices, but rebleeding can be effectively prevented by standard scheduled band ligations. Anticoagulation does not prevent variceal relapse. The improvement in the survival of patients treated with anticoagulation needs to be confirmed in future studies.

CT features of non-malignant portal vein thrombosis: a pictorial review

Portal vein thrombosis (PVT) is a rare clinical entity in general population, but a relatively frequent entity in liver cirrhosis. Severe PVT-related complications are potentially lethal, such as ischemic intestinal infarction and complications of portal hypertension. Additionally, occlusive PVT can not only increase the incidence of variceal rebleeding, but also significantly decrease the cirrhotic patients' survival. Based on the clinical significance of PVT, early diagnosis is very critical to allow for rapid establishment of appropriate treatment and improvement of prognosis. Dynamic CT scan is an important diagnostic modality of PVT. The objective of this pictorial review is to illustrate various CT features of non-malignant portal vein thrombosis and its associated abnormalities. Evolution of portal vein thrombosis, such as stage, degree, and extension of thrombus, can be evaluated according to CT demonstrations, which is helpful to timely adopt appropriate treatment modality. Other associated CT findings include the dilation of collateral veins around the obstructed portion of portal vein and the hepatic perfusion and morphology abnormalities.

Anticoagulation for the treatment of thrombotic complications in patients with cirrhosis

Cirrhotic patients can develop thrombotic complications, which in this group of patients occur with a greater frequency than in the general population. Portal vein thrombosis (PVT) is the most common thrombotic phenomenon, although deep venous thrombosis and pulmonary embolism can also occur. Risk factors for thrombosis include inherited and acquired deficiency of factors involved in anticoagulation mechanisms, venous stasis of the portal vein owing to architectural derangement of the liver and possibly local factors related to the endothelium. Clinical manifestations of PVT range from asymptomatic disease to a life-threatening complication, and although it is no longer considered an absolute contraindication for liver transplant, its presence may require challenging surgical techniques, which entail greater morbidity. Anticoagulation therapy is henceforth an important strategy to treat cirrhotic patients with PVT, although experience in this group of patients is limited. Vitamin K antagonists and low-molecular-weight heparin have been used successfully, achieving recanalization of the thrombosed vessel in patients with cirrhosis; however, the precise drug regimen management and monitoring has not be fully explored in this group of patients.

Venous thromboembolism in cirrhosis

The cirrhosis population represents a unique subset of patients who are at risk for both bleeding and developing venous thromboembolic events (VTEs). It has been commonly misunderstood that these patients are naturally protected from thrombosis by deficiencies in coagulation factors. As a result, the cirrhosis population is often falsely perceived to be "autoanticoagulated." However, the concept of "autoanticoagulation" conferring protection from thrombosis is a misnomer. While patients with cirrhosis may have a bleeding predisposition, not uncommonly they also experience thrombotic events. The concern for this increased bleeding risk often makes anticoagulation a difficult choice. Prophylactic and therapeutic management of VTE in patients with cirrhosis is a difficult clinical problem with the lack of clear established guidelines. The elucidation of laboratory and/or clinical predictors of VTE will be useful in this setting. This review serves to examine VTE and the use of anticoagulation in the cirrhosis population.

Transjugular intrahepatic portosystemic shunt may be superior to conservative therapy for variceal rebleeding in cirrhotic patients with non-tumoral portal vein thrombosis: a hypothesis

The presence of occlusive portal vein thrombosis (PVT) greatly changes the natural history of liver cirrhosis, because it not only significantly increases the incidence of variceal rebleeding but also negatively influences the survival. However, due to the absence of strong evidence, no standard treatment algorithm for the secondary prophylaxis of variceal bleeding in cirrhotic patients with non-tumoral PVT has been established. Previous randomized controlled trials have demonstrated that transjugular intrahepatic portosystemic shunt (TIPS) can significantly decrease the incidence of variceal rebleeding in cirrhotic patients without PVT, compared with conservative therapy (i.e., endoscopic plus pharmacological therapy). Further, several large cohort studies have confirmed that TIPS can effectively prevent variceal rebleeding in cirrhotic patients with non-tumoral PVT. On the other hand, TIPS can facilitate recanalizing the thrombosed portal vein by endovascular manipulations, even in the presence of cavernous transformation of the portal vein (CTPV). More importantly, successful TIPS insertions can maintain the persistent portal vein patency, and avoid thrombus extension into the portal venous system. By comparison, anticoagulation therapy can achieve portal vein recanalization only in patients with partial PVT, but not in those with occlusive PVT or CTPV, and the use of anticoagulants may aggravate the risk of variceal bleeding in cirrhotic patients with a history of variceal bleeding. Collectively, we hypothesize that TIPS may be superior to conservative therapy for the prevention of variceal rebleeding in cirrhotic patients with non-tumoral PVT. Randomized controlled trials should be conducted to evaluate the survival benefit of TIPS in these patients.

Prospective evaluation of anticoagulation and transjugular intrahepatic portosystemic shunt for the management of portal vein thrombosis in cirrhosis

BACKGROUND

There is no established management algorithm for portal vein thrombosis (PVT) in cirrhotic patients. The aim of our study was to prospectively evaluate anticoagulation and transjugular intrahepatic portosystemic shunt (TIPS) to treat PVT.

METHODS

Cirrhotics with non-malignant PVT were included. Low weight molecular heparin anticoagulation was considered in all; TIPS was indicated if thrombosis progressed or anticoagulation was contraindicated. Patients who were not anticoagulated nor received TIPS served as controls.

RESULTS

Fifty-six patients (of whom 21 controls) were included. PVT was occlusive in 11/35, with extension to the superior mesenteric or splenic vein in 13/35. In the study group 33 patients were anticoagulated, with a recanalization rate of 36% (12/33) compared with 1/21 among controls. A time interval between appearance of thrombosis and anticoagulation < 6 months predicted chance of repermeation. Thrombus progression occurred in 15/21 non anticoagulated patients and in 5/33 anticoagulated patients (P < 0.001). TIPS was placed in six patients. There were five variceal bleedings and two intestinal venous ischaemia episodes in the control group, compared with one variceal bleeding episode in the study group.

CONCLUSIONS

In cirrhotics with PVT, a treatment algorithm using anticoagulation and TIPS achieves a good chance of complete repermeation, reduces portal hypertensive complications, and decreases the rate of thrombosis progression.

Efficacy and safety of anticoagulation on patients with cirrhosis and portal vein thrombosis

BACKGROUND & AIMS

Portal vein thrombosis (PVT) is a frequent event in patients with cirrhosis; it can be treated with anticoagulants, but there are limited data regarding safety and efficacy of this approach. We evaluated this therapy in a large series of patients with cirrhosis and non-neoplastic PVT.

METHODS

We analyzed data from 55 patients with cirrhosis and PVT, diagnosed from June 2003 to September 2010, who received anticoagulant therapy for acute or subacute thrombosis (n = 31) or progression of previously known PVT (n = 24). Patients with cavernomatous transformation were excluded. Thrombosis was diagnosed, and recanalization was evaluated by using Doppler ultrasound, angio-computed tomography, and/or angio-magnetic resonance imaging analyses.

RESULTS

Partial or complete recanalization was achieved in 33 patients (60%; complete in 25). Early initiation of anticoagulation was the only factor significantly associated with recanalization. Rethrombosis after complete recanalization occurred in 38.5% of patients after anticoagulation therapy was stopped. Despite similar baseline characteristics, patients who achieved recanalization developed less frequent liver-related events (portal hypertension-related bleeding, ascites, or hepatic encephalopathy) during the follow-up period, but this difference was not statistically significant (P = .1). Five patients developed bleeding complications that were probably related to anticoagulation. A platelet count <50 × 109/L was the only factor significantly associated with higher risk for experiencing a bleeding complication. There were no deaths related to anticoagulation therapy.

CONCLUSIONS

Anticoagulation is a relatively safe treatment that leads to partial or complete recanalization of the portal venous axis in 60% of patients with cirrhosis and PVT; it should be maintained indefinitely to prevent rethrombosis.

Portal vein thrombosis, cirrhosis, and liver transplantation

Portal vein thrombosis is not uncommon in candidates for transplantation. Partial thrombosis is more common than complete thrombosis. Despite careful screening at evaluation, a number of patients are still found with previously unrecognized thrombosis per-operatively. The objective is to recanalize the portal vein or, if recanalization is not achievable, to prevent the extension of the thrombus so that a splanchnic vein can be used as the inflow vessel to restore physiological blood flow to the allograft. Anticoagulation during waiting time and transjugular intrahepatic portosystemic shunt (TIPS) are two options to achieve these goals. TIPS may achieve recanalization in patients with complete portal vein thrombosis. However, a marked impairment in liver function, which is a characteristic feature of most candidates for transplantation, may be a contraindication for TIPS. Importantly, the MELD score is artificially increased by the administration of vitamin K antagonists due to prolonged INR. When patency of the portal vein and/or superior mesenteric vein is not achieved, only non-anatomical techniques (renoportal anastomosis or cavoportal hemitransposition) can be performed. These techniques, which do not fully reverse portal hypertension, are associated with higher morbidity and mortality risks. Multivisceral transplantation including the liver and small bowel needs to be evaluated. In the absence of prothrombotic states that may persist after transplantation, there is no evidence that pre-transplant portal vein thrombosis justifies long term anticoagulation post-transplantation, provided portal flow has been restored through conventional end-to-end portal anastomosis.

Management of hepatic vascular diseases

Primary damage to hepatic vessels is rare. (i) Hepatic arterial disorders, related mostly to iatrogenic injury and occasionally to systemic diseases, lead to ischemic cholangiopathy. (ii) Hepatic vein or inferior vena cava thrombosis, causing primary Budd-Chiari syndrome, is related typically to a combination of underlying prothrombotic conditions, particularly myeloproliferative neoplasms, factor V Leiden, and oral contraceptive use. The outcome of Budd-Chiari syndrome has markedly improved with anticoagulation therapy and, when needed, angioplasty, stenting, TIPS, or liver transplantation. (iii) Extrahepatic portal vein thrombosis is related to local causes (advanced cirrhosis, surgery, malignant or inflammatory conditions), or general prothrombotic conditions (mostly myeloproliferative neoplasms or factor II gene mutation), often in combination. Anticoagulation at the early stage prevents thrombus extension and, in 40% of the cases, allows for recanalization. At the late stage, gastrointestinal bleeding related to portal hypertension can be prevented in the same way as in cirrhosis. (iv) Sinusoidal obstruction syndrome (or venoocclusive disease), caused by agents toxic to bone marrow progenitors and to sinusoidal endothelial cells, induces portal hypertension and liver dysfunction. Decreasing the intensity of myeloablative regimens reduces the incidence of sinusoidal toxicity. (v) Obstruction of intrahepatic portal veins (obliterative portal venopathy) can be associated with autoimmune diseases, prothrombotic conditions, or HIV infection. The disease can eventually be complicated with end-stage liver disease. Extrahepatic portal vein obstruction is common. Anticoagulation should be considered. (vi) Nodular regenerative hyperplasia is induced by the uneven perfusion due to obstructed sinusoids, or portal or hepatic venules. It causes pure portal hypertension.

Emergency anticoagulation treatment for cirrhosis patients with portal vein thrombosis and acute variceal bleeding

OBJECTIVE

To determine the safety and efficacy of anticoagulation treatment for portal vein thrombosis in cirrhosis patients with acute variceal bleeding, with patient eligibility determined by contrast ultrasonography findings.

MATERIALS AND METHODS

This prospective study included 23 consecutive cirrhosis patients (63.8 ± 11.8 years old, 12 males and 11 females) with emergency admission for acute variceal bleeding with or without portal vein thrombus. Eligibility for anticoagulation treatment was determined by positive intra-thrombus enhancement on contrast ultrasonography (perflubutane microbubble agent, 0.0075 mL/kg) performed before endoscopy. Low-molecular-weight heparin was administered after hemostasis was achieved by band ligation. Repeated band ligation or injection sclerotherapy combined with argon plasma coagulation was performed for variceal disappearance.

RESULTS

Hemostasis was achieved in all 10 patients with active bleeding. Five of these patients had portal vein thrombus, and all showed positive intra-thrombus enhancement on contrast ultrasonography. Anticoagulation treatment of these five patients resulted in complete recanalization of the portal vein within 2-11 days. There were no significant differences in the number of endoscopic treatment sessions or the length of hospital stay between the groups with and without thrombosis, and no complications including rebleeding were reported. Long term, none of the patients who continued oral anticoagulation treatment had recurrence of thrombosis (4/5). Variceal recurrence occurred only in the non-thrombosis group (2/18) during the follow-up period (median: 351 days).

CONCLUSIONS

Early anticoagulation treatment in cirrhosis patients with portal vein thrombosis and acute variceal bleeding may be safe, tolerated, and effective in cases with positive intra-thrombus enhancement on contrast ultrasonography.

Antithrombotic therapy for VTE disease: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

BACKGROUND

This article addresses the treatment of VTE disease.

METHODS

We generated strong (Grade 1) and weak (Grade 2) recommendations based on high-quality (Grade A), moderate-quality (Grade B), and low-quality (Grade C) evidence.

RESULTS

For acute DVT or pulmonary embolism (PE), we recommend initial parenteral anticoagulant therapy (Grade 1B) or anticoagulation with rivaroxaban. We suggest low-molecular-weight heparin (LMWH) or fondaparinux over IV unfractionated heparin (Grade 2C) or subcutaneous unfractionated heparin (Grade 2B). We suggest thrombolytic therapy for PE with hypotension (Grade 2C). For proximal DVT or PE, we recommend treatment of 3 months over shorter periods (Grade 1B). For a first proximal DVT or PE that is provoked by surgery or by a nonsurgical transient risk factor, we recommend 3 months of therapy (Grade 1B; Grade 2B if provoked by a nonsurgical risk factor and low or moderate bleeding risk); that is unprovoked, we suggest extended therapy if bleeding risk is low or moderate (Grade 2B) and recommend 3 months of therapy if bleeding risk is high (Grade 1B); and that is associated with active cancer, we recommend extended therapy (Grade 1B; Grade 2B if high bleeding risk) and suggest LMWH over vitamin K antagonists (Grade 2B). We suggest vitamin K antagonists or LMWH over dabigatran or rivaroxaban (Grade 2B). We suggest compression stockings to prevent the postthrombotic syndrome (Grade 2B). For extensive superficial vein thrombosis, we suggest prophylactic-dose fondaparinux or LMWH over no anticoagulation (Grade 2B), and suggest fondaparinux over LMWH (Grade 2C).

CONCLUSION

Strong recommendations apply to most patients, whereas weak recommendations are sensitive to differences among patients, including their preferences.

Management of anticoagulation for portal vein thrombosis in individuals with cirrhosis: a systematic review

Non-neoplastic portal vein thrombosis (PVT) is an increasingly recognized complication of liver cirrhosis. It is often diagnosed fortuitously and can be either partial or complete. The clinical significance of PVT is not obvious except in some situations such as when patients are on the waiting list for liver transplantation. The only known therapy is anticoagulation which has been shown to permit the disappearance of thrombosis and to prevent further extension. Anticoagulation is a challenging therapy in individuals with liver cirrhosis because of the well-recognized coagulation abnormalities observed in that setting and because of the increased risk of bleeding, especially from gastrointestinal tract caused by portal hypertension. We herein review the current knowledge on that topic in order to highlight the advantages and disadvantages of the currently proposed therapeutic attitudes in face of the diagnosis of PVT in individuals with cirrhosis.

Hypercoagulability in cirrhosis: causes and consequences

Decreased levels of most coagulation factors and thrombocytopenia are the main haemostatic abnormalities of cirrhosis. As a consequence, this condition was, until recently, considered as the prototype acquired coagulopathy responsible for bleeding. However, recent evidence suggests that it should, rather, be regarded as a condition associated with normal or even increased thrombin generation. The bleeding events that occur in these patients should, therefore, be explained by the superimposed conditions that frequently occur in this setting. Due to elevated levels of factor VIII (procoagulant driver) in combination with decreased protein C (anticoagulant driver), which are typically found in patients with cirrhosis, a procoagulant imbalance, defined as a partial resistance to the in vitro anticoagulant action of thrombomodulin, can be demonstrated. Whether this in vitro hypercoagulability is truly representative of what occurs in vivo remains to be established. However, the hypothesis that it may have clinical consequences is attractive and deserves attention. The possible consequences that we discuss herein include whether (i) cirrhosis is a condition associated with increased risk of venous thromboembolism or portal vein thrombosis; (ii) the hypercoagulability associated with cirrhosis has any other role outside coagulation (i.e. progression of liver fibrosis); and (iii) anticoagulation should be used in cirrhosis. Although apparently provocative, considering anticoagulation as a therapeutic option in patients with cirrhosis is now supported by a rationale of increasing strength. There may be subgroups of patients who benefit from anticoagulation to treat or prevent thrombosis and to slow hepatic fibrosis. Clinical studies are warranted to explore these therapeutic options.

Occlusive portal vein thrombosis as a new marker of decompensated cirrhosis

Natural history of liver cirrhosis is divided into compensated and decompensated stage. Traditionally, the markers of decompensated cirrhosis include ascites, variceal hemorrhage, hepatic encephalopathy and jaundice. The clinical importance of portal vein thrombosis (PVT) is increasingly recognized in patients with liver cirrhosis. The presence of PVT is not only an independent predictor of failure to control active variceal bleeding and prevent variceal rebleeding, but also significantly associated with increased mortality in patients with liver cirrhosis. Besides, it greatly influences the technical success and outcome of endovascular interventional treatment and liver transplantation for liver cirrhosis and its secondary portal hypertension. Thus, we hypothesize that PVT should be regarded as a critical marker of decompensated cirrhosis, whether clinical events such as the development of ascites, encephalopathy, and variceal bleeding occur or not. Our hypothesis adds PVT into the definition of decompensated cirrhosis and reminds clinicians and investigators that PVT plays a vital role in natural history of liver cirrhosis. Further, it is essential to construct a new system of preventing and treating liver cirrhosis in the presence of PVT.

Transjugular intrahepatic portosystemic shunt for portal vein thrombosis with symptomatic portal hypertension in liver cirrhosis

BACKGROUND & AIMS

Data on the management of portal vein thrombosis (PVT) in patients with decompensated cirrhosis are extremely limited, particularly in the cases of the transjugular intrahepatic portosystemic shunt (TIPS). We assessed the outcome of TIPS for PVT in patients with cirrhosis and symptomatic portal hypertension and determined the predictors of technical success and survival.

METHODS

In the retrospective study, 57 consecutive patients receiving TIPS were enrolled between December 2001 and September 2008. All were diagnosed with chronic PVT, and 30 had portal cavernoma. Indications for TIPS were variceal hemorrhage (n = 56) and refractory ascites (n = 1).

RESULTS

TIPS were successfully placed in 75% of patients (43/57). The independent predictors of technical success included portal cavernoma, and the degree of thrombosis within the main portal vein (MPV), the portal vein branches, and the superior mesenteric vein. Only one patient died of severe procedure-related complication. The cumulative 1-year shunt dysfunction and hepatic encephalopathy rates were 21% and 25%, respectively. The cumulative 1- and 5-year variceal re-bleeding rates differed significantly between the TIPS success and failure groups (10% and 28% versus 43% and 100%, respectively; p = 0.0004), while the cumulative 1- and 5-year survival rates were similar between the two groups (86% and 77% versus 78% and 62%, respectively; p = 0.34). The independent predictor of survival in PVT patients with decompensated cirrhosis was the degree of MPV occlusion (hazard ratio 0.189, 95% CI 0.042-0.848).

CONCLUSIONS

TIPS should be considered a safe and feasible alternative therapy for chronic PVT in selected patients with decompensated cirrhosis. Both technical success and survival were closely associated with the degree of MPV occlusion.

Extrahepatic portal vein thrombosis in children and adolescents: Influence of genetic thrombophilic disorders

AIM: To explore the prevalence of local and genetic thrombophilic disorders as risk factors for portal vein thrombosis (PVT) in our series, the largest ever published in pediatric literature.

METHODS: We conducted a case-control study enrolling 31 children with PVT and 26 age-matched controls. All were screened for thrombophilia, including genetic disorders, protein C, protein S and homocysteine deficiencies. All coagulation parameters were studied at least 3 mo after the diagnosis of portal vein obstruction.

RESULTS: In our study we showed that most pediatric patients with PVT have local prothrombotic risk factors, which are probably the most important factors leading to PVT. However, there is a clear association between the presence of prothrombotic disorders and PVT, suggesting that these increase the risk of thrombosis in patients with local factors such as perinatal umbilical vein catheterization or sepsis.

CONCLUSION: Patients with PVT should be screened for inherited prothrombotic disorders regardless of a history of an obvious local risk factor.

Systematic review: portal vein thrombosis in cirrhosis

BACKGROUND

As current imaging techniques in cirrhosis allow detection of asymptomatic portal vein thrombosis during routine ultrasonography, more patients with cirrhosis are diagnosed with portal vein thrombosis. Although a consensus on noncirrhotic extra-hepatic portal vein thrombosis has been published, no such consensus exists for portal vein thrombosis with cirrhosis.

AIM

To perform a systematic review of nonmalignant portal vein thrombosis in cirrhosis in terms of prevalence, pathogenesis, diagnosis, clinical course and management.

METHODS

Studies were identified by a search strategy using MEDLINE and EMBASE.

RESULTS

Portal vein thrombosis is encountered in 10-25% of cirrhotics. In terms of pathophysiology, cirrhosis is no longer considered a hypocoagulable state; rather than a bleeding risk in cirrhosis, various clinical studies support a thrombotic potential. Clinical findings of portal vein thrombosis in cirrhosis vary from asymptomatic disease to a life-threatening condition at first presentation. Optimal management of portal vein thrombosis in cirrhosis is currently not addressed in any consensus publication. Treatment strategies most often include the use of anticoagulation, while thrombectomy and transjugular intrahepatic portosystemic shunts are considered second-line options.

CONCLUSIONS

Portal vein thrombosis in cirrhosis has many unresolved issues, which are often the critical problems clinicians encounter in their everyday practice. We propose a possible research agenda to address these unresolved issues.

Management of portal vein thrombosis in cirrhotic patients

Portal vein thrombosis (PVT) not associated with hepatocellular carcinoma is considered a frequent complication of liver cirrhosis but, unlike PVT occurring in non-cirrhotic patients, very few data are available on its natural history and management. The reduced portal blood flow velocity is the main determinant of PVT but, as in other venous thromboses, multiple factors local and systemic, inherited or acquired often can concur with. PVT has a variety of clinical presentations ranging from asymptomatic to life-threatening diseases like gastroesophageal bleeding or acute intestinal ischemia. It is usually diagnosed by Doppler ultrasound but computed tomography and magnetic resonance imaging are useful to study the extent of thrombosis and the involvement of the abdominal organs. The risk of bleeding mainly determined by the presence of gastroesophageal varices and clotting alterations causes concern for the treatment of PVT in cirrhotic patients. To date, anticoagulant therapy seems to be indicated only in patients awaiting liver transplantation. This review focuses on the definition of the subgroups of patients with cirrhosis that might benefit from treatment of PVT and examines the pros and cons of the available treatments in terms of efficacy, monitoring and safety, providing also perspectives for future studies.