Splanchnic vein thrombosis in myeloproliferative neoplasms: treatment algorithm 2018

Role of red cell mass evaluation in myeloproliferative neoplasms with splanchnic vein thrombosis and normal hemoglobin value: a study of the France Intergroupe des Syndromes myeloprolifératifs

Not available.

Portal Vein Thrombosis: State-of-the-Art Review

Background: Portal vein thrombosis (PVT) is a rare disease with an estimated incidence of 2 to 4 cases per 100,000 inhabitants. The most common predisposing conditions for PVT are chronic liver diseases (cirrhosis), primary or secondary hepatobiliary malignancy, major infectious or inflammatory abdominal disease, or myeloproliferative disorders. Methods: PVT can be classified on the basis of the anatomical site, the degree of venous occlusion, and the timing and type of presentation. The main differential diagnosis of PVT, both acute and chronic, is malignant portal vein invasion, most frequently by hepatocarcinoma, or constriction (typically by pancreatic cancer or cholangiocarcinoma). Results: The management of PVT is based on anticoagulation and the treatment of predisposing conditions. The aim of anticoagulation in acute thrombosis is to prevent the extension of the clot and enable the recanalization of the vein to avoid the development of complications, such as intestinal infarction and portal hypertension. Conclusions: The treatment with anticoagulant therapy favors the reduction of portal hypertension, and this allows for a decrease in the risk of bleeding, especially in patients with esophageal varices. The anticoagulant treatment is generally recommended for at least three to six months. Prosecution of anticoagulation is advised until recanalization or lifelong if the patient has an underlying permanent pro-coagulant condition that cannot be corrected or if there is thrombosis extending to the mesenteric veins.

Cancer-associated splanchnic vein thrombosis: Clinical implications and management considerations

Splanchnic vein thrombosis (SVT), a thrombosis which involves the portal, mesenteric, and splenic veins, and the Budd-Chiari syndrome, represents an uncommon type of venous thromboembolism (VTE). Like with deep vein thrombosis of the lower extremities and pulmonary embolism, ample evidence suggests a significant association between SVT and cancer, particularly intra-abdominal solid malignancies (e.g. hepatobiliary and pancreatic cancers) and myeloproliferative neoplasms (MPN). Clinical symptoms of SVT in cancer patients can be ambiguous, and frequently attributed to the primary cancer itself. Alternatively, SVT may be asymptomatic and detected incidentally during cancer staging or follow-up evaluations. SVT can also precede the diagnosis of cancer and has been associated with poorer outcomes in patients with liver or pancreatic cancers. Therefore, an unprovoked SVT warrants a thorough evaluation for an underlying malignancy or MPN. Cancer-associated SVT carries a high risk of VTE extension, recurrence and bleeding. Extended anticoagulant treatment is often required in the absence of a high bleeding risk. Guidelines suggest treatment with either low molecular weight heparin (LMWH) or direct oral anticoagulants (DOACs), although available data on the safety and effectiveness of DOACs in these patients is limited. This comprehensive review outlines the epidemiology, pathogenesis, risk factors, and diagnosis of cancer-associated SVT and underscores the importance of comprehensive patient evaluation and evidence-based management.

Exploring the Molecular Aspects of Myeloproliferative Neoplasms Associated with Unusual Site Vein Thrombosis: Review of the Literature and Latest Insights

Myeloproliferative neoplasms (MPNs) are the leading causes of unusual site thrombosis, affecting nearly 40% of individuals with conditions like Budd-Chiari syndrome or portal vein thrombosis. Diagnosing MPNs in these cases is challenging because common indicators, such as spleen enlargement and elevated blood cell counts, can be obscured by portal hypertension or bleeding issues. Recent advancements in diagnostic tools have enhanced the accuracy of MPN diagnosis and classification. While bone marrow biopsies remain significant diagnostic criteria, molecular markers now play a pivotal role in both diagnosis and prognosis assessment. Hence, it is essential to initiate the diagnostic process for splanchnic vein thrombosis with a JAK2 V617F mutation screening, but a comprehensive approach is necessary. A multidisciplinary strategy is vital to accurately determine the specific subtype of MPNs, recommend additional tests, and propose the most effective treatment plan. Establishing specialized care pathways for patients with splanchnic vein thrombosis and underlying MPNs is crucial to tailor management approaches that reduce the risk of hematological outcomes and hepatic complications.

The molecular landscape of myeloproliferative neoplasms associated with splanchnic vein thrombosis: Current perspective

BCR::ABL1-negative myeloproliferative neoplasms (MPNs) are classically represented by polycythemia vera, essential thrombocythemia, and primary myelofibrosis. BCR::ABL1-negative MPNs are significantly associated with morbidity and mortality related to an increased risk of thrombo-hemorrhagic events. They show a consistent association with splanchnic vein thrombosis (SVT), either represented by the portal, mesenteric or splenic vein thrombosis, or Budd-Chiari Syndrome. SVT is also a frequent presenting manifestation of MPN. MPNs associated with SVT show a predilection for younger women, high association with JAK2V617F mutation, low JAK2V617F variant allele frequency (generally <10 %), and low rates of CALR, MPL, or JAK2 exon 12 mutations. Next-Generation Sequencing techniques have contributed to deepening our knowledge of the molecular landscape of such cases, with potential diagnostic and prognostic implications. In this narrative review, we analyze the current perspective on the molecular background of MPN associated with SVT, pointing as well future directions in this field.

Polycythemia Vera: Barriers to and Strategies for Optimal Management

Polycythemia vera (PV) is a subtype of myeloproliferative neoplasms characterized by impaired quality of life and severe complications. Despite the increasingly in-depth knowledge of this condition, it necessitates a multifaceted management approach to mitigate symptoms and prevent thrombotic and hemorrhagic events, ensuring prolonged survival. The therapeutic landscape has been revolutionized in recent years, where venesection and hydroxycarbamide associated with antiplatelet therapy have a central role and are now accompanied by other drugs, such as interferon and Janus kinase inhibitors. Ongoing research and advancements in targeted therapies hold promise for further enhancing the therapeutic choice for PV management.

Diagnosis and Management of Cardiovascular Risk in Patients with Polycythemia Vera

Polycythemia vera (PV) is a myeloproliferative neoplasm characterized by aberrant myeloid lineage hematopoiesis with excessive red blood cell and pro-inflammatory cytokine production. Patients with PV present with a range of thrombotic and hemorrhagic symptoms that affect quality of life and reduce overall survival expectancy. Thrombotic events, transformation into acute myeloid leukemia, and myelofibrosis are largely responsible for the observed mortality. Treatment of PV is thus primarily focused on symptom control and survival extension through the prevention of thrombosis and leukemic transformation. Patients with PV frequently experience thrombotic events and have elevated cardiovascular risk, including hypertension, dyslipidemias, obesity, and smoking, all of which negatively affect survival. To reduce the risk of thrombotic complications, PV therapy should aim to normalize hemoglobin, hematocrit, and leukocytosis and, in addition, identify and modify cardiovascular risk factors. Herein, we review what is currently known about the associated cardiovascular risk and propose strategies for diagnosing and managing patients with PV.

Splanchnic Vein Thrombosis in Myelofibrosis-An Underappreciated Hallmark of Disease Phenotype

Splanchnic vein thrombosis (SVT) encompasses thrombosis in the vessels of the splanchnic basin and has a relatively rare occurrence with a reported frequency in the general population of 1-2%. An episode of seemingly unprovoked SVT almost always triggers a diagnostic work-up for a Philadelphia chromosome-negative myeloproliferative neoplasm (MPN), since atypical site thrombosis is a hallmark of MPN-associated thrombophilia. Primary myelofibrosis (PMF) is a rare MPN with an estimated incidence between 0.1 and 1/100,000 per year. Although prothrombotic tendency in PMF is not envisioned as a subject of specific therapeutic management, unlike other MPNs, such as polycythemia vera (PV) and essential thrombocythemia (ET), thrombotic risk and SVT prevalence in PMF may be comparably high. Additionally, unlike PV and ET, SVT development in PMF may depend more on procoagulant mechanisms involving endothelium than on blood cell activation. Emerging results from registry data also suggest that PMF patients with SVT may exhibit lower risk and better prognosis, thus highlighting the need for better thrombotic risk stratification and identifying a subset of patients with potential benefit from antithrombotic prophylaxis. This review highlights specific epidemiological, pathogenetic, and clinical features pertinent to SVT in myelofibrosis.

Spontaneous bacterial peritonitis complicating extensive splanchnic vein thrombosis, a rare manifestation of essential thrombocythemia: A case report

Key Clinical Message

Clinicians should be mindful of the rare occurrence of spontaneous bacterial peritonitis in essential thrombocythemia with extensive splanchnic vein thrombosis, especially when patients with ascites exhibit fever and abdominal pain.

Abstract

Spontaneous bacterial peritonitis (SBP) complicating extensive splanchnic vein thrombosis (SVT) is a rare manifestation of essential thrombocythemia (ET). In the absence of any hypercoagulable state, JAK2 mutation can be an important risk factor for extensive SVT. Evaluation for SBP is crucial when non-cirrhotic patient exhibits fever, abdominal pain and tenderness in the background of ascites after ruling out common pathologies such as tubercular peritonitis, acute pancreatitis, Budd-Chiari syndrome and ovarian malignancy. We present a case of SBP complicating pre-hepatic portal hypertension with ascites in a 44-years-old female. On further evaluation, extensive SVT with portal cavernoma in the setting of ET was identified. She was managed with cytoreductive therapy and anticoagulation, resulting in symptom resolution.

Portal vein thrombosis as the presenting manifestation of JAK2 positive myeloproliferative neoplasm

Deep venous thrombosis (DVT) is a complication of myeloproliferative neoplasms (MPNs). However, DVTs in unusual sites such as portal vein thrombosis (PVT) are rare and may be the first clinical manifestation of occult MPNs. There is a need for increasing awareness of such manifestations; so, here we discuss a patient who presented with new portal vein thrombosis, underwent further studies, was ultimately diagnosed with JAK2 positive MPN, and started on appropriate treatment with improvement of thrombosis and controlled hematocrit.

Molecular Genetics of Thrombotic Myeloproliferative Neoplasms: Implications in Precision Oncology

Classical BCR-ABL-negative myeloproliferative neoplasms (MPN) include polycythaemia vera, essential thrombocythaemia, and primary myelofibrosis. Unlike monogenic disorders, a more complicated series of genetic mutations are believed to be responsible for MPN with various degrees of thromboembolic and bleeding complications. Thrombosis is one of the early manifestations in patients with MPN. To date, the driver genes responsible for MPN include JAK2, CALR, MPL, TET2, ASXL1, and MTHFR. Affords have been done to elucidate these mutations and the incidence of thromboembolic events. Several lines of evidence indicate that mutations in JAK2, MPL, TET2 and ASXL1 gene and polymorphisms in several clotting factors (GPIa, GPIIa, and GPIIIa) are associated with the occurrence and prevalence of thrombosis in MPN patients. Some polymorphisms within XRCC1, FBG, F2, F5, F7, F12, MMP9, HPA5, MTHFR, SDF-1, FAS, FASL, TERT, ACE, and TLR4 genes may also play a role in MPN manifestation. This review aims to provide an insightful overview on the genetic perspective of thrombotic complications in patients with MPN.

Splanchnic Vein Thrombosis in Myeloproliferative Neoplasms: Treatment Considerations and Unmet Needs

Patients who develop splanchnic vein thrombosis (SVT) in the setting of a myeloproliferative neoplasm (MPN) are at risk for complications including portal hypertension, bleeding, thrombosis, and death. Prompt multidisciplinary treatment is thus necessary to prevent long-term sequelae. However, optimal management strategies are not well established due to a paucity of data. In this review, we very briefly discuss the epidemiology, pathophysiology, and prognosis of MPN-SVT and then more comprehensively explore treatment considerations of MPN-SVT, including anticoagulation, endovascular/surgical intervention, and cytoreductive therapy. We will also highlight current gaps in our knowledge of MPN-SVT and conclude by suggesting future directions to optimize the treatment of MPN-SVT and improve outcomes.

Essential Thrombocythemia: One-Center Data in a Changing Disease

Introduction: Essential thrombocythemia is a chronic myeloproliferative neoplasm associated with thrombo-hemorrhagic events and the progression to myelofibrosis or acute myeloid leukemia. The purpose of this article is to present real-world data on ET cases diagnosed and managed between 1998 and 2020 in the largest, tertiary hematology reference center in Romania and to evaluate the impact of thrombotic events on survival. Methods: A real-world, retrospective cohort-type study was conducted. We collected and statistically analyzed data from 168 patients who met the 2016 WHO diagnostic criteria for ET and who were managed between 1998 and 2020 in our center. Results: The median age at diagnosis of ET was 51.8 years, with a female predominance (66.07%). The JAK2V617F mutation was detected in 60.71% of patients. Leukocytosis at diagnosis was associated with a higher risk of thrombosis, and JAK2V617F-positive cases exhibited a 1.5-fold higher risk of developing thrombotic events. The average survival in ET with major thrombosis was 14.5 years versus 20.6 years in ET cases without major thrombosis. Other predictors of survival were high-risk IPSET score and age >60 years. Conclusions: Romanian patients diagnosed with ET are generally younger than 60 years and are predominantly female. The occurrence of thrombotic events was influenced by gender, leukocyte count at diagnosis and JAK2V617F positivity. Survival was impacted by age, the presence of JAK2V617F mutation, hypertension, major thrombotic complications and IPSET score. Notably, these findings warrant careful interpretation and further confirmation in the setting of prospective studies.

Clinical significance of neutrophil extracellular traps biomarkers in thrombosis

Neutrophil extracellular traps (NETs) may be associated with the development of thrombosis. Experimental studies have confirmed the presence of NETs in thrombi specimens and potential role of NETs in the mechanisms of thrombosis. Clinical studies also have demonstrated significant changes in the levels of serum or plasma NETs biomarkers, such as citrullinated histones, myeloperoxidase, neutrophil elastase, nucleosomes, DNA, and their complexes in patients with thrombosis. This paper aims to comprehensively review the currently available evidence regarding the change in the levels of NETs biomarkers in patients with thrombosis, summarize the role of NETs and its biomarkers in the development and prognostic assessment of venous thromboembolism, coronary artery diseases, ischemic stroke, cancer-associated thromboembolism, and coronavirus disease 2019-associated thromboembolism, explore the potential therapeutic implications of NETs, and further discuss the shortcomings of existing NETs biomarkers in serum and plasma and their detection methods.

Primary Myelofibrosis in the Prefibrotic Stage Presenting as Portal, Splenic, and Superior Mesenteric Vein Thrombosis: A Case Report and Review of the Literature

INTRODUCTION

Myeloproliferative neoplasms are the most common cause of splanchnic vein thrombosis in the absence of cirrhosis or nearby malignancy.

CASE PRESENTATION

A 31-year-old male presented to the emergency department with epigastric pain associated with mild thrombocytosis and elevated levels of aminotransferases, lactate dehydrogenase, and C-reactive protein. Contrast-enhanced abdominal computed tomography revealed splanchnic venous thrombosis that involved the portal, splenic, and superior mesenteric veins, without signs of chronic liver disease. Anticoagulation with warfarin was immediately started. Diagnostic work-up was remarkable for the presence of the JAK2 V617T mutation and hypercellular bone marrow, with increased myeloid cells and atypical megakaryocytes, consistent with primary myelofibrosis in a prefibrotic stage. No other hypercoagulable conditions were identified.

DISCUSSION

We present a rare case of primary myelofibrosis in the prefibrotic stage presenting as portal-splenic-superior mesenteric vein thrombosis. This demonstrates that extensive splanchnic vein thrombosis may be the onset manifestation of myeloproliferative neoplasms, even in early stages and in the absence of concomitant hypercoagulable conditions. The presence of the JAK2 mutation is an important prothrombotic risk factor that can, per se, contribute to large venous thrombosis.

How I manage myeloproliferative neoplasm-unclassifiable: Practical approaches for 2022 and beyond

Myeloproliferative neoplasm (MPN)-unclassifiable (MPN-U) or not otherwise specified represents a rare, poorly defined and heterogeneous group of MPNs. Disease incidence is difficult to define but likely represents close to 5% of all MPNs when strict World Health Organisation (WHO) criteria are applied. Dynamic review over time is required to assess if the disease can be re-classified into another MPN entity. A diagnosis of MPN-U leads to many challenges for both the patient and physician alike including lack of agreed monitoring and therapeutic guidelines, validated prognostic markers and licenced therapies coupled with exclusion from clinical trials. MPN-U has an inherent risk of an aggressive clinical course and transformation in some but who, and when to treat in the chronic phase, including identifying who may require more aggressive therapy at an earlier stage, remains elusive. Moreover, despite the significant thrombotic risk, there is no agreement on systematic primary thromboprophylaxis. We hereby provide a contemporary overview of MPN-U in addition to four illustrative cases providing our collective suggested approaches to clinical challenges.

Paroxysmal Nocturnal Hemoglobinuria in the Context of a Myeloproliferative Neoplasm: A Case Report and Review of the Literature

Paroxysmal nocturnal hemoglobinuria (PNH) is characterized by intravascular hemolytic anemia and thrombosis and is notoriously associated with aplastic anemia and myelodysplastic syndromes. Rarer associations include myeloproliferative neoplasms (MPNs), which are also burdened by increased thrombotic tendency. The therapeutic management of this rare combination has not been defined so far. Here, we describe a 62-year-old man who developed a highly hemolytic PNH more than 10 years after the diagnosis of MPN. The patient started eculizumab, obtaining good control of intravascular hemolysis but without amelioration of transfusion-dependent anemia. Moreover, we performed a review of the literature regarding the clinical and pathogenetic significance of the association of PNH and MPN. The prevalence of PNH clones in MPN patients is about 10%, mostly in association with JAK2V617F-positive myelofibrosis. Thrombotic events were a common clinical presentation (35% of subjects), sometimes refractory to combined treatment with cytoreductive agents, anticoagulants, and complement inhibitors. The latter showed only partial effectiveness in controlling hemolytic anemia and, due to the paucity of data, should be taken in consideration after a careful risk/benefit evaluation in this peculiar setting.

Challenging anticoagulation cases: Acute extensive portal vein thrombosis in a patient without cirrhosis - Evidence-based management of a rare clinical entity

Acute non-cirrhotic and non-malignant portal vein thrombosis (aPVT) is a rare and heterogenous condition. Current guidelines recommend early initiation of therapeutic anticoagulation to prevent extension of thrombosis, and favor recanalization. Although not formally defined, a poor outcome in the acute setting would include thrombosis extension with progression to intestinal infarction. Patients are also at risk of negative long-term outcomes related to complications of portal hypertension, such as variceal bleeding, ascites, and portal cholangiopathy. Identifying patients at risk of these events despite early initiation of anticoagulation remains challenging. Trials comparing treatment strategies in those failing standard therapy with meaningful radiological and clinical endpoints, whether in the short or long term, are desperately needed. The objective of this review will be to discuss a real-life clinical case and propose a treatment approach for aPVT based on the available evidence. We will mainly focus on management strategies including anticoagulation, prognostic factors, and options beyond anticoagulation, such as thrombolysis, thrombectomy, and transjugular intrahepatic portosystemic shunts. This review will not cover tumor portal vein thrombosis or thrombosis associated with cirrhosis.

Portal vein thrombosis patients harboring JAK2V617F have poor long-term outcomes despite anticoagulation

Non-cirrhotic portal vein thrombosis (ncPVT) most often occurs in the setting of intraabdominal proinflammatory processes. Less often, ncPVT may result from primary hematologic thrombophilia (most commonly JAK2V617F). Although these etiologic categories are pathophysiologically distinct, they are treated similarly using anticoagulation. We conducted a retrospective assessment of outcomes among ncPVT patients harboring JAK2V617F, and compared them to outcomes among patients with other etiologies for ncPVT, to determine whether anticoagulation alone is adequate therapy for JAK2V617F associated PVT. Outcomes were complete radiographic resolution (CRR) of PVT, recanalization (RC) of occlusive PVT, and development of significant portal hypertension (SPH). Three-hundred-thirty ncPVT patients seen between 1/2000 and 1/2019, including 37 harboring JAK2V617F (JAK2), 203 with other evident etiology (OE) for PVT, and 90 with no evident etiology (NE) for PVT followed for a median 29 months (53, 21, and 32 months respectively). Outcomes among the JAK2 cohort were dismal relative to the other groups. CRR rates were 8%, 31%, and 55% for the JAK2, NE, and OE cohorts respectively (multivariable HR JAK2:OE = 0.15 (0.05, 0.49), p = 0.0016). RC rates were 16%, 33%, and 49% for the JAK2, NE, and OE cohorts respectively (multivariable HR for RC JAK2:OE = 0.24 (0.09, 0.63), p = 0.0036). SPH rates were 49%, 32%, and 17% for the JAK2, NE, and OE cohorts respectively (multivariable HR for SPH JAK2:OE = 1.23 (0.62, 2.42), p = 0.5492). Given the strikingly poor outcomes among patients harboring JAK2V617F, anticoagulation alone does not appear to be adequate therapy for this cohort. Further investigation into thrombolysis and/or thrombectomy as an adjunct to anticoagulation is merited in this high-risk group.

Cancer-Associated Splanchnic Vein Thrombosis

Splanchnic vein thrombosis (SVT), which includes portal, mesenteric, and splenic vein thrombosis and the Budd-Chiari syndrome, is an infrequent manifestation of venous thromboembolism (VTE). Like typical site VTE, SVT is also frequently associated with cancer, particularly intra-abdominal solid malignancies and myeloproliferative neoplasms (MPNs). The clinical presentation of SVT is nonspecific. Symptoms may be related to the underlying malignancy, and thrombosis is incidentally diagnosed by imaging studies for cancer staging or follow-up in a substantial proportion of cases. The occurrence of SVT predicts worse prognosis in patients with liver or pancreatic cancer and, not uncommonly, SVT may precede the diagnosis of cancer. Therefore, the occurrence of an apparently unprovoked SVT should prompt careful patient evaluation for the presence of an underlying malignancy or MPN. Cancer patients carry a high risk of VTE extension and recurrence and long-term anticoagulant treatment is suggested in the absence of high risk of bleeding. Either LMWH or direct oral anticoagulants (DOACs) are suggested for the treatment of patients with cancer-related SVT, although limited experience is available on the use of DOACs in these settings. Vitamin K antagonists (VKAs) are suggested for the short and long-term treatment of SVT associated with MPN. This review outlines the epidemiological aspects, pathogenesis, risk factors, and diagnosis of cancer-associated SVT, and addresses questions regarding the management of this challenging condition.

Treatment of portal vein thrombosis: an updated narrative review

Portal vein thrombosis (PVT) is the most frequent among the splanchnic vein thrombosis, accounting for 90% of cases. More than half of PVT are provoked by liver cirrhosis, solid cancer or myeloproliferative neoplasms. The remaining cases are non-malignant non-cirrhotic PVT and include either unprovoked events or thrombosis secondary to other less common risk factors (e.g. abdominal surgery, intrabdominal inflammations/infections, or hormonal stimuli). Anticoagulant therapy in patients with acute symptomatic PVT should be started early after diagnosis, if no active bleeding, to obtain greater vessel recanalization and reduce the occurrence of portal-hypertension related complications. Gastroesophageal varices do not represent a contraindication to anticoagulant treatment, as long as adequate measures have been undertaken for the prophylaxis of gastroesophageal bleeding. Different treatment options (unfractionated or low molecular weight heparin, vitamin K antagonists and direct oral anticoagulants [DOACs]) can be considered. In this narrative review we will discuss the treatment of PVT in the three most common scenarios (cirrhosis-associated, cancer-associated and non-malignant non-cirrhotic PVT). We will also discuss the role of the DOACs and summarise recent guidelines on this topic.

Splanchnic vein thrombosis: Clinical manifestations, risk factors, management, and outcomes

BACKGROUND

Clinical manifestations and optimal management strategies in patients with splanchnic vein thrombosis (SVT) are not well characterized.

METHODS

We conducted a retrospective cohort study including all newly diagnosed SVT evaluated between January 2007 and December 2018. Efficacy outcome was thrombosis resolution, and safety outcomes included death and occurrence of bleeding.

RESULTS

We included 155 patients with a mean age of 56.2 (18-87). Local risk factors were present in 118 (76.1%) patients and 30 (19.4%) had only systemic/thrombophilia. Local risk factors included abdominal cancers (31%), surgery (20.6%) and liver cirrhosis (19.4%). Thrombophilia screening was conducted in approximately 50% of patients. Factor V Leiden or Prothrombin G20210A mutations were observed in 7.1% of patients whereas 14.4% were JAK2V617F mutation positive. Most common manifestations at onset were abdominal pain (56.1%), whereas 44.6% were incidentally found. Portal vein thrombosis was observed more in primary cases (91.9% vs. 69.5%, p = 0.012). Anticoagulation was used in 93.5% cases. Indefinite anticoagulation was used more frequently in primary SVT (62.2% vs. 41.5%, p = 0.045). Thrombosis resolution and bleeding complications among primary (without local risk factors) and secondary (with local risk factors) SVT were observed in 48.5%, 65%, 8.1%, and 11.9%, respectively with no difference when comparing patients treated with direct oral anticoagulants or warfarin and/or low molecular weight heparin (58% vs. 62%, p = 0.326, 9% vs. 12%, p = 0.518).

CONCLUSIONS

In this cohort anticoagulation resulted in partial or complete thrombosis resolution in a significant proportion of patients with an acceptable bleeding risk regardless local risk factors or type of anticoagulant.

Prevention and Management of Thrombosis in BCR/ABL-Negative Myeloproliferative Neoplasms

Myeloproliferative neoplasms (MPNs) are clonal disorders of the hematopoietic stem cell. Classical BCR/ABL-negative MPNs include polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF). Thrombotic events are a major cause of morbidity and mortality in these patients. Pathogenesis of blood clotting activation involves various abnormalities of platelets, erythrocytes, and leukocytes, as well as dysfunctions of endothelial cells. Patients with MPN can be stratified in "high risk" or "low risk" of thrombosis according to established risk factors. ET and PV clinical management is highly dependent on the patient's thrombotic risk, and a risk-oriented management strategy to treat these diseases is strongly recommended. In this review, we give an overview of risk factors, pathogenesis, and thrombosis prevention and treatment in MPN.

Prevention of recurrent thromboembolism in myeloproliferative neoplasms: review of literature and focus on direct oral anticoagulants

Myeloproliferative neoplasms (MPNs), including polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (MF) are stem cell clonal neoplasms characterized by expansion of late myeloid cells. Thrombosis risk is elevated in MPNs and contributes significantly to morbidity and mortality. Current consensus guidelines make no specific recommendations regarding anticoagulant choice for the treatment of venous thromboembolism (VTE) in MPNs, with most evidence supporting the use of vitamin K antagonists (VKAs) for secondary prophylaxis. However, direct oral anticoagulants (DOACs) are now increasingly being used, although with limited data on safety and efficacy in MPNs specifically. The widespread adoption of DOACs is based on new, high-quality evidence demonstrating safety and efficacy of DOAC treatment for cancer-associated VTE. However, these studies include few if any MPN patients, and MPNs have disease-specific considerations that may elevate thrombosis and bleeding risk. The purpose of this review is to discuss evidence behind current treatment recommendations for thrombosis in MPNs, with special attention to the use of DOACs.

Portal vein thrombosis due to essential thrombocythemia with limited cutaneous systemic sclerosis

Portal vein thrombosis is caused by various diseases, including liver cirrhosis, cancer, abdominal infection, and myeloproliferative disorders. Essential thrombocythemia is one of the myeloproliferative disorders in which the bone marrow produces excessive amount of platelets and can be accompanied by various thrombotic diseases; however, essential thrombocythemia with limited cutaneous systemic sclerosis has not been reported yet. We herein report a case of extensive portal vein thrombosis due to essential thrombocythemia with limited cutaneous systemic sclerosis. A 49-year-old woman was referred to our hospital due to liver dysfunction. Extended portal vein thrombosis, splenomegaly, and thrombocytosis were founded. The examination of Janus kinase 2 V617F mutation in the bone marrow was positive. These findings resulted in the diagnosis of portal vein thrombosis due to essential thrombocythemia. Furthermore, Raynaud's phenomenon, finger's sclerosis, and positive anti-centromere antibody led to limited cutaneous systemic sclerosis. To further analyze the causal relationship between essential thrombocythemia and limited cutaneous systemic sclerosis, platelet-derived growth factor was examined. High level of serum platelet-derived growth factor, possibly caused by high platelet count due to essential thrombocythemia, was observed. As platelet-derived growth factor has been reportedly associated with the occurrence of systemic sclerosis, the present case indicates the possible causal link between essential thrombocythemia and limited cutaneous systemic sclerosis through high platelet-derived growth factor.

Budd-Chiari Syndrome: An Uncommon Cause of Chronic Liver Disease that Cannot Be Missed

Budd-Chiari syndrome (BCS), or hepatic venous outflow obstruction, is a rare cause of liver disease that should not be missed. Variable clinical presentation among patients with BCS necessitates a high index of suspicion to avoid missing this life-threatening diagnosis. BCS is characterized as primary or secondary, depending on etiology of venous obstruction. Most patients with primary BCS have several contributing risk factors leading to a prothrombotic state. A multidisciplinary stepwise approach is integral in treating BCS. Lifelong anticoagulation is recommended. Long-term monitoring of patients for development of cirrhosis, complications of portal hypertension, hepatocellular carcinoma, and progression of underlying diseases is important.

Treatment of unusual thrombotic manifestations

Venous thrombosis rarely occurs at unusual sites such as cerebral, splanchnic, upper-extremity, renal, ovarian, or retinal veins. Clinical features, symptoms, and risk factors of rare thrombotic manifestations are heterogeneous and in large part differ from those typical of the commonest manifestations of venous thrombosis at the lower extremities. The therapeutic approach also varies widely according to the affected site, whether cerebral, abdominal, or extraabdominal. To date, anticoagulant therapy for thrombosis at unusual sites is generally accepted, but the optimal therapeutic approach remains challenging. This review is focused on the treatment of unusual thrombotic manifestations as reported in the most recent guidelines and according to the updated scientific literature.

From Budd-Chiari syndrome to acquired von Willebrand syndrome: thrombosis and bleeding complications in the myeloproliferative neoplasms

Thrombotic and hemorrhagic complications are prevalent in patients with essential thrombocythemia, polycythemia vera, and myelofibrosis. Given the impact on morbidity and mortality, reducing the risk of thrombosis and/or hemorrhage is a major therapeutic goal. Historically, patients have been risk stratified on the basis of traditional factors, such as advanced age and thrombosis history. However, multiple factors contribute to the thrombotic tendency, including gender, mutational profile, inflammatory stress, and abnormal cell adhesion. Management includes cardiovascular risk reduction and use of antiplatelet therapy, depending on myeloproliferative neoplasm subtype and mutational status. Anticoagulation is a mainstay of therapy for those with venous thrombosis, but practice patterns remain heterogeneous. Cytoreduction is indicated for higher-risk patients, but efficacy may depend on the involved vascular bed. Management of special situations, such as unusual site thrombosis, bleeding, the perioperative period, and pregnancy, are especially challenging. In this article, risk factors and treatment strategies for myeloproliferative neoplasm thrombosis and bleeding, including special situations, are reviewed. Insights gained from recent studies may lead to the development of a more precise risk classification and tailored therapy.

[Gene mutation spectrum and clinical characteristics analysis of 178 patients with essential thrombocytosis]

目的

分析原发性血小板增多症（ET）患者基因突变谱及临床特征。

方法

对2009年2月1日至2018年11月1日收治的178例初诊ET患者进行回顾性分析。

结果

全部178例患者中，男89例，女89例，中位初诊年龄为49.5（3~86）岁。JAK2V617F基因突变频率为16.45%（1.67%~43.90%），CALR基因突变频率为40.00%（10.00%~49.15%），MPL基因突变频率为25.10%（25.00%~40.00%）。与CALR基因突变的患者相比，JAK2V617F基因突变患者具有较高的发病年龄（P=0.035）、初诊白细胞计数（P=0.040）、初诊血红蛋白浓度（P=0.001）和较低的初诊血小板计数（P=0.002）。47例（27.01%）患者诊断ET前发生血栓事件，3例（1.72%）诊断ET后发生血栓事件。多因素分析结果显示，年龄>60岁（P=0.013，OR=4.595，95%CI1.382~15.282）、心血管危险因素（P<0.001，OR=8.873，95%CI2.921~26.955）为血栓事件的危险因素，CALR基因突变（P=0.032，OR=0.126，95%CI0.019~0.838）为血栓事件的保护性因素。年龄>60岁（P=0.042，OR=4.045，95%CI1.053~15.534）是影响ET患者总生存时间的危险因素。年龄≤60岁、年龄>60岁患者的OS时间分别为（115.231±1.899）、（83.291±4.991）个月（χ²=6.406，P=0.011）。

结论

心血管危险因素、年龄>60岁为ET患者血栓事件的危险因素，CALR基因突变为血栓事件的保护性因素。年龄>60岁是影响ET患者总生存的危险因素。

From Budd-Chiari syndrome to acquired von Willebrand syndrome: thrombosis and bleeding complications in the myeloproliferative neoplasms

Thrombotic and hemorrhagic complications are prevalent in patients with essential thrombocythemia, polycythemia vera, and myelofibrosis. Given the impact on morbidity and mortality, reducing the risk of thrombosis and/or hemorrhage is a major therapeutic goal. Historically, patients have been risk stratified on the basis of traditional factors, such as advanced age and thrombosis history. However, multiple factors contribute to the thrombotic tendency, including gender, mutational profile, inflammatory stress, and abnormal cell adhesion. Management includes cardiovascular risk reduction and use of antiplatelet therapy, depending on myeloproliferative neoplasm subtype and mutational status. Anticoagulation is a mainstay of therapy for those with venous thrombosis, but practice patterns remain heterogeneous. Cytoreduction is indicated for higher-risk patients, but efficacy may depend on the involved vascular bed. Management of special situations, such as unusual site thrombosis, bleeding, the perioperative period, and pregnancy, are especially challenging. In this article, risk factors and treatment strategies for myeloproliferative neoplasm thrombosis and bleeding, including special situations, are reviewed. Insights gained from recent studies may lead to the development of a more precise risk classification and tailored therapy.

Addressing and proposing solutions for unmet clinical needs in the management of myeloproliferative neoplasm-associated thrombosis: A consensus-based position paper

This article presents the results of a group discussion among an ad hoc constituted Panel of experts aimed at highlighting unmet clinical needs (UCNs) in the management of thrombotic risk and thrombotic events associated with Philadelphia-negative myeloproliferative neoplasms (Ph-neg MPNs). With the Delphi technique, the challenges in Ph-neg MPN-associated thrombosis were selected. The most clinically relevant UCNs resulted in: (1) providing evidence of the benefits and risks of direct oral anticoagulants, (2) providing evidence of the benefits and risks of cytoreduction in patients with splanchnic vein thrombosis without hypercythemia, (3) improving knowledge of the role of the mutated endothelium in the pathogenesis of thrombosis, (4) improving aspirin dosing regimens in essential thrombocythemia, (5) improving antithrombotic management of Ph-neg MPN-associated pregnancy, (6) providing evidence for the optimal duration of anticoagulation for prophylaxis of recurrent VTE, (7) improving knowledge of the association between somatic gene mutations and risk factors for thrombosis, and (8) improving the grading system of thrombosis risk in polycythemia vera. For each of these issues, proposals for advancement in research and clinical practice were addressed. Hopefully, this comprehensive overview will serve to inform the design and implementation of new studies in the field.

Primary myelofibrosis: spectrum of imaging features and disease-related complications

Primary myelofibrosis is a chronic clonal stem cell disorder that results in a build-up of marrow fibrosis and dysfunction, hypermetabolic states, and myeloid metaplasia. The clinical and radiological consequences can be quite diverse and range from the manifestations of osteosclerosis and extramedullary haematopoiesis to thrombohaemorrhagic complications from haemostatic dysfunction. In addition, there is the challenge of identifying less well-recognised sites of extramedullary haematopoiesis and their site-specific complications. The intent of this article is to illustrate the spectrum of primary myelofibrosis as declared though multimodality imaging, with examples of both common and rarer disease manifestations.

Pregnancy in a Woman with Latent Myeloproliferative Neoplasm Induced Chronic Portal Vein Thrombosis, Portal Cavernoma, and Gastric Varices

Extra-hepatic portal vein thrombosis (EHPVO) represents the obstruction of the portal vein outside the liver and is not related to chronic liver disease or neoplasia. In chronic EHPVO, collateral veins and portal hypertension develop, resulting in splenomegaly and variceal formation. Myeloproliferative neoplasms (MPN) are the most frequent acquired etiology of EHPVO. These conditions put pregnant women at increased risk of vascular complications, including venous thrombosis, occlusion of the placental circulation, and variceal bleeding. In this report, we present a 36-year-old pregnant woman with chronic, anticoagulated EHPVO secondary to latent MPN who developed severe intrauterine growth restriction and had cesarean section at 32+1 weeks for increased umbilical doppler resistance and breech presentation. The article will emphasize outcome and management of pregnancies complicated by chronic EHPVO, portal hypertension, and MPN.

Thromboembolic events in polycythemia vera

Thromboembolic events and cardiovascular disease are the most prevalent complications in patients with polycythemia vera (PV) compared with other myeloproliferative disorders and are the major cause of morbidity and mortality in this population. Moreover, a vascular complication such as arterial or venous thrombosis often leads to the diagnosis of PV. The highest rates of thrombosis typically occur shortly before or at diagnosis and decrease over time, probably due to the effects of treatment. Important risk factors include age (≥ 60 years old) and a history of thrombosis; elevated hematocrit and leukocytosis are also associated with an increased risk of thrombosis. The goal of therapy is to reduce the risk of thrombosis by controlling hematocrit to < 45%, a target associated with reduced rates of cardiovascular death and major thrombosis. Low-risk patients (< 60 years old with no history of thrombosis) are managed with phlebotomy and low-dose aspirin, whereas high-risk patients (≥ 60 years old and/or with a history of thrombosis) should be treated with cytoreductive agents. Interferon and ruxolitinib are considered second-line therapies for patients who are intolerant of or have an inadequate response to hydroxyurea, which is typically used as first-line therapy. In this review, we discuss factors associated with thrombosis and recent data on current treatments, including anticoagulation, highlighting the need for more controlled studies to determine the most effective cytoreductive therapies for reducing the risk of thrombosis in patients with PV.

Splanchnic venous thrombosis in JAK2 V617F mutation positive myeloproliferative neoplasms - long term follow-up of a regional case series

Background

Splanchnic Vein Thrombosis (SVT) is strongly associated with underlying JAK2 V617F positive myeloproliferative neoplasms (MPN).

Methods

Patients attending the tertiary haematology service in Northern Ireland with SVT and underlying JAK2 V617F MPN were identified by consultant staff. A retrospective audit was undertaken to examine therapeutic interventions and relevant outcomes. Descriptive statistics were used for qualitative data whilst students t-test allowed comparison of quantitative data.

Results

We report on the medium to long term follow-up of fourteen patients presenting with SVT on the basis of JAK2 V617F positive MPN. Females comprised 78.5% of the patients and there was an average age of 47.3 years at time of diagnosis. There was significant morbidity evident at diagnosis with liver transplantation attempted in all patients with Budd Chiari (n = 3), oesophageal varices present in 57.1%, ascites present in 42.8% and splenomegaly evident in 71.4%. 42.8% of patients did not exhibit classical phenotypic blood count findings for MPN at time of diagnosis. Over a median follow-up of 88.5 months (range = 8-211 months) recurrence of SVT was only documented in the setting of interventional liver procedure. Major haemorrhagic complications were recorded in 35.7% of patients and there was an association with dual anticoagulation and antiplatelet use. Recurrent thrombosis outside of the splanchnic venous system occurred in 28.5% of patients, predominantly occurring off therapeutic anticoagulation. No deaths were recorded and one transformation to myelofibrosis was seen during follow-up. Cytoreduction therapies were routinely used but had a high discontinuation rate due to cytopenias and intolerance.

Conclusion

This analysis highlights the complexities of management of this group of patients over a period of long follow-up with a focus on the evidence behind therapeutic options.