The JAK2 V617F mutation in patients with cerebral venous thrombosis

Cerebral venous thrombosis in patients with autoimmune disease, hematonosis or coronavirus disease 2019: Many familiar faces and some strangers

BACKGROUND

Cerebral venous thrombosis, a rare stroke, is characterized by neurological dysfunction caused by bleeding and/or infarction resulting from venous sinus thrombosis, the so-called venous stroke. Current guidelines recommend anticoagulants as first-line therapy in the treatment of venous stroke. With complicated causes of cerebral venous thrombosis, treatment is difficult, especially when combined with autoimmune diseases, blood diseases, and even COVID-19.

AIMS

This review summarizes the pathophysiological mechanisms, epidemiology, diagnosis, treatment, and clinical prognosis of cerebral venous thrombosis combined with autoimmune diseases, blood diseases, or infectious diseases such as COVID-19.

CONCLUSION

A systematic understanding of particular risk factors that should not be neglected when unconventional cerebral venous thrombosis occurs and for a scientific understanding of pathophysiological mechanisms, clinical diagnosis, and treatment, thus contributing to knowledge on special types of venous stroke.

Characteristics of patients with cerebral sinus venous thrombosis and JAK2 V617F mutation

OBJECTIVES

Janus kinase 2 (JAK2-V617F) mutations can cause thrombocytosis, polycythemia and hyper viscosity leading to cerebral sinus venous thrombosis (CSVT). However, data regarding the characteristics and prevalence of JAK2-V617F mutation in patients with CSVT are currently lacking. We aimed to evaluate the characteristics of CSVT patients that carry the JAK2 mutation.

MATERIALS AND METHODS

Data of consecutive patients with CSVT, admitted to three large academic medical centers between 2010 and 2020, were retrospectively studied. Demographics, clinical presentations, radiological and clinical outcome parameters were compared between carriers of the JAK2-V617F mutation and controls.

RESULTS

Out of 404 patients diagnosed with CSVT, 26 patients (6.5%) were carriers of the mutation. JAK2 mutation carriers more often had thrombocytosis (54% vs. 1%, p < 0.001). Furthermore, carriers of the JAK2 mutation less often had involvement of the transverse sinus (50% vs. 68%, p = 0.021). Finally, patients with the JAK2 mutation were more prone to have intracerebral hemorrhage (ICH, 31% vs. 17%, p = 0.044), but there was no significant difference between groups in terms of mortality nor functional outcome.

CONCLUSIONS

JAK2 mutation is not uncommon in patients with CSVT and should be routinely screened for in this population. CSVT in JAK2 mutation carriers may have a tendency toward involving specific venous sinuses and is associated with a higher rate of ICH but similar overall prognosis.

Dural Venous Sinus Thrombosis and Papilledema Related to JAK2 Mutation: A Case Series

BACKGROUND

Dural venous sinus thrombosis (DVST) is an important cause of papilledema. Patients diagnosed with DVST should undergo work-up for underlying hypercoagulable state, including genetic causes. One important prothrombotic mutation is in the JAK2 gene, which is a driver of myeloproliferative neoplasms including polycythemia vera (PV). We aimed to determine the prevalence of JAK2 mutation in patients in presenting to neuro-ophthalmology clinic with DVST and papilledema.

METHODS

Retrospective case series of patients seen in a tertiary neuro-ophthalmology practice who presented with papilledema due to DVST and were investigated for presence of JAK2 mutation.

RESULTS

Four out of 15 patients with DVST (26%) were found to have JAK2 V617F mutation which led to subsequent diagnosis of PV in 2. One additional patient had a known diagnosis of essential thrombocytosis. We describe the clinical presentation of these four patients with papilledema and JAK2 mutation.

CONCLUSIONS

A significant proportion of patients with papilledema secondary to DVST will harbor mutations in the JAK2 gene. Clinicians should be aware of this mutation as early testing will facilitate timely diagnosis and treatment of myeloproliferative disease to improve prognosis and reduce risk of recurrent thrombotic events.

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.

Direct Oral Anticoagulants for the Prevention and Acute Treatment of Cancer-Associated Thrombosis

Cancer is a major risk factor for venous thromboembolism (VTE), and cancer-associated thrombosis (CAT) constitutes approximately 15-25% of all VTE cases. For decades, the standard treatment for CAT used to be daily subcutaneous low molecular weight heparin (LMWH). Data on the safety and efficacy of the direct oral anticoagulants (DOACs) in this population emerged only in recent years and specific DOACs were included into recent guidelines recommendations. In this narrative review of the literature, we reported the results of the phase III randomized controlled trials that evaluated the DOACs for the prevention and the acute treatment of CAT. For the acute phase treatment, the anti-Xa inhibitors (apixaban, edoxaban, rivaroxaban) showed better efficacy than LMWH in preventing VTE recurrence; however, rivaroxaban and edoxaban were also associated with an increased risk of bleeding events. For primary prevention of CAT in ambulatory cancer patients starting chemotherapy, apixaban and rivaroxaban showed better efficacy than placebo but a trend towards higher bleeding rates. Recent guidelines suggest the DOACs for the treatment of CAT in selected cancer patients (eg, low bleeding risk, no luminal gastrointestinal or genitourinary malignancies, no interfering medications). The DOACs are also suggested for primary thromboprophylaxis in selected ambulatory cancer patients at high risk of VTE (eg, Khorana score ≥2 prior to starting new chemotherapy, low bleeding risk, no interfering medications).

A Case of Bilateral Cerebral Venous Sinus Thrombosis: More Than Meets the Eye

Cerebral venous sinus thrombosis (CVST) is a rare etiology of stroke that results from inherited and/or acquired conditions, which can present in a variety of symptoms. CVST in the setting of the 2019 coronavirus disease (COVID-19) has rarely been observed. Herein, we present the case of a 32-year-old female with a recent history of COVID-19 subsequently found to have CVST involving bilateral transverse sinuses. Further workup demonstrated several hypercoagulable conditions, which were likely exacerbated by the viral infection. This case demonstrates an atypical outcome for young, COVID-19-positive patients, which emphasizes the importance of diligence when examining symptomatic patients with a history of COVID-19 infection. The patient was treated with apixaban therapy with radiographic resolution of bilateral CVST and improved vision.

Janus Kinase-2 V617F Mutation and Antiphospholipid Syndrome in Cerebral Sinus Venous Thrombosis: Natural History and Retrospective Bicenter Analysis

Background

Cerebral sinus venous thrombosis (CSVT) is a rare neurovascular entity, usually associated with acquired or genetic hypercoagulable states. In up to 30% of the cases it remains idiopathic. Bone marrow proliferation disorders that are associated with Janus Kinase 2 V617F mutation (JAK-2) are known causes of the systemic and cerebral thrombosis—at times despite normal blood counts—for which hematologic treatment exists. However, JAK-2 prevalence in the CSVT cases is not clear.

Methods

In this retrospective analysis, data of 236 patients with CSVT admitted to two tertiary centers between 2010 and 2020 were analyzed, with emphasis on laboratory and imaging data and clinical and interventional outcomes.

Results

A total of 236 patients were included in the analysis. The patients' median age was 42 years and the average age was 44 years (±19 years), with 59% female patients. JAK-2 positivity rate was 18% (among 77 patients tested for the mutation). Patients with normal blood counts on presentation comprised 36% of the JAK-2 positive cases. Other hypercoagulability states were also investigated, with the antiphospholipid syndrome (APLA) showing the highest prevalence (11%) followed by other etiologies including oral contraceptive use, Factor V Leiden, prothrombin mutation, and malignancy. Selected JAK-2, APLA, and prothrombin mutation cases showed a more severe clinical course.

Conclusion

JAK-2 mutation is underdiagnosed and its screening may be warranted in the cases of idiopathic CSVT, even despite normal blood counts, to allow disease-modifying treatment and blood cell count monitoring. JAK-2, APLA, and prothrombin mutation may be associated with a more complicated clinical course.

Cerebral venous thrombosis and myeloproliferative neoplasms: A three-center study of 74 consecutive cases

The recent association of cerebral venous thrombosis (CVT) with COVID‐19 vaccinations prompted the current retrospective review of 74 cases of CVT (median age = 44 years, range 15–85; 61% females) associated with myeloproliferative neoplasms (MPNs), seen at the Mayo Clinic, Catholic University of Rome, and University of Florence, between 1991 and 2021. Disease‐specific frequencies were 1.3% (39/2893), 1.2% (21/1811) and 0.2% (3/1888) for essential thrombocythemia, polycythemia vera and primary myelofibrosis, respectively. Cerebral venous thrombosis occurred either prior to (n = 20, 27%), at (n = 32, 44%) or after (n = 22) MPN diagnosis. A total of 72% of patients presented with headaches. Transverse (51%), sagittal (43%) and sigmoid sinuses (35%) were involved with central nervous system hemorrhage noted in 10 (14%) patients. In all, 91% of tested patients harbored JAK2V617F. An underlying thrombophilic condition was identified in 19 (31%) cases and history of thrombosis in 10 (14%). Treatment for CVT included systemic anticoagulation alone (n = 27) or in conjunction with aspirin (n = 24), cytoreductive therapy (n = 14), or both (n = 9). At a median follow‐up of 5.1 years (range 0.1–28.6), recurrent CVT was documented in three (4%) patients while recurrent arterial and venous thromboses and major hemorrhage were recorded in 11%, 9% and 14%, respectively. Follow‐up neurological assessment revealed headaches (n = 9), vision loss (n = 1) and cognitive impairment (n = 1). The current study lends clarity to MPN‐associated CVT and highlights its close association with JAK2V617F, younger age and female gender. Clinical features that distinguish COVID vaccine‐related CVT from MPN‐associated CVT include, in the latter, lower likelihood of concurrent venous thromboses and intracerebral hemorrhage; as a result, MPN‐associated CVT was not fatal.

Philadelphia chromosome-negative myeloproliferative neoplasms in younger adults: A critical discussion of unmet medical needs, with a focus on pregnancy

Myeloproliferative neoplasms (MPN) are traditionally regarded as a disease of older adults, though a not negligible fraction of cases occurs at a younger age, including women of childbearing potential. MPN in younger patients, indeed, offer several challenges for the clinical hematologist, that goes from difficulties in reaching a timely and accurate diagnosis to a peculiar thrombotic risk, with a relatively high incidence of thromboses in unusual sites (as the splanchnic veins or the cerebral ones). Moreover, the issue of pregnancy is recently gaining more attention as maternal age is rising and molecular screening are widely implemented, leading to a better recognition of these cases, both before and during pregnancy. In the present work we aim at discussing four clinical topic that we identified as areas of uncertainty or true unmet medical needs in the management of younger patients with MPN, with a particular focus on the topic of pregnancy. For each of these topics, we critically reviewed the available evidence that support treatment decisions, though acknowledging that recommendations in this field are mostly based on expert opinion or derived from guidelines of other clinical conditions that share with MPN a high vascular risk, as antiphospholipid syndrome. Taking into consideration both the lack of evidence-based data and the clinical heterogeneity of MPN, we support an individualized strategy of counseling and management for both young patients and for expectant mother with MPN.

Classical Philadelphia-negative myeloproliferative neoplasms (MPNs): A continuum of different disease entities

Classical Philadelphia-negative myeloproliferative neoplasms (MPNs) are clonal hematopoietic stem cell-derived disorders characterized by uncontrolled proliferation of differentiated myeloid cells and close pathobiologic and clinical features. According to the 2016 World Health Organization (WHO) classification, MPNs include polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF). The 2016 revision aimed in particular at strengthening the distinction between masked PV and JAK2-mutated ET, and between prefibrotic/early (pre-PMF) and overt PMF. Clinical manifestations in MPNs include constitutional symptoms, microvascular disorders, thrombosis and bleeding, splenomegaly secondary to extramedullary hematopoiesis, cytopenia-related symptoms, and progression to overt MF and acute leukemia. A dysregulation of the JAK/STAT pathway is the unifying mechanistic hallmark of MPNs, and is guided by somatic mutations in driver genes including JAK2, CALR and MPL. Additional mutations in myeloid neoplasm-associated genes have been also identified, with established prognostic relevance, particularly in PMF. Prognostication of MPN patients relies on disease-specific clinical models. The increasing knowledge of MPN biology led to the development of integrated clinical and molecular prognostic scores that allow a more refined stratification. Recently, the therapeutic landscape of MPNs has been revolutionized by the introduction of potent, selective JAK inhibitors (ruxolitinib, fedratinib), that proved effective in controlling disease-related symptoms and splenomegaly, yet leaving unmet critical needs, owing the lack of disease-modifying activity. In this review, we will deal with molecular, clinical, and therapeutic aspects of the three classical MPNs aiming at highlighting either shared characteristics, that overall define a continuum within a single disease family, and uniqueness, at the same time.

Cerebral venous thrombosis: a practical guide

All neurologists need to be able to recognise and treat cerebral venous thrombosis (CVT). It is difficult to diagnose, partly due to its relative rarity, its multiple and various clinical manifestations (different from 'conventional' stroke, and often mimicking other acute neurological conditions), and because it is often challenging to obtain and interpret optimal and timely brain imaging. Although CVT can result in death or permanent disability, it generally has a favourable prognosis if diagnosed and treated early. Neurologists involved in stroke care therefore also need to be aware of the treatments for CVT (with varying degrees of supporting evidence): the mainstay is prompt anticoagulation but patients who deteriorate despite treatment can be considered for endovascular procedures (endovascular thrombolysis or thrombectomy) or neurosurgery (decompressive craniotomy). This review summarises current knowledge on the risk factors, diagnosis, treatment and prognosis of CVT in adults, and highlights some areas for future research.

Thrombotic, Vascular, and Bleeding Complications of the Myeloproliferative Neoplasms

Thrombotic, vascular, and bleeding complications are the most frequent causes of morbidity and mortality in myeloproliferative neoplasms (MPNs). The interplay and reciprocal amplification between two factors are considered to lead to thrombosis in MPNs: (1) circulating blood cell-intrinsic abnormalities caused by an MPN driver mutation in their hematopoietic progenitor/stem cells, interacting with vascular endothelial cells, show prothrombotic and proadhesive phenotypes; and (2) a state of usually subclinical systemic inflammation that fuels the thrombotic tendency. Prevention and treatment require maintenance of hematocrit less than 45% and cytoreductive therapy in patients with a high risk for thrombotic and vascular complications.

Cerebral Venous Thrombosis: What's New?

Thrombosis of the cerebral veins and sinuses (CVT) is a distinct cerebrovascular disorder that, unlike arterial stroke, most often affects children and young adults, especially women. In this review, we will summarize recent advances on the knowledge of patients with CVT.

Pathogenesis and Management in Cerebrovenous Outflow Disorders

In keeping with its status as one of the major causes of disability and mortality worldwide, brain damage induced by cerebral arterial disease has been the subject of several decades of scientific investigation, which has resulted in a vastly improved understanding of its pathogenesis. Brain injury mediated by venous etiologies, however, such as cerebral, jugular, and vertebral venous outflow disturbance, have been largely ignored by clinicians. Unfortunately, this inattention is not proportional to the severity of cerebral venous diseases, as the impact they exact on the quality of life of affected patients may be no less than that of arterial diseases. This is evident in disease sequelae such as cerebral venous thrombosis (CVT)-mediated visual impairment, epilepsy, and intracranial hypertension; and the long-term unbearable head noise, tinnitus, headache, dizziness, sleeping disorder, and even severe intracranial hypertension induced by non-thrombotic cerebral venous sinus (CVS) stenosis and/or internal jugular venous (IJV) stenosis. In addition, the vertebral venous system (VVS), a large volume, valveless vascular network that stretches from the brain to the pelvis, provides a conduit for diffuse transmission of tumors, infections, or emboli, with potentially devastating clinical consequences. Moreover, the lack of specific features and focal neurologic signs seen with arterial etiologies render cerebral venous disease prone to both to misdiagnoses and missed diagnoses. It is therefore imperative that awareness be raised, and that as comprehensive an understanding as possible of these issues be cultivated. In this review, we attempt to facilitate these goals by systematically summarizing recent advances in the diagnosis and treatment of these entities, including CVT, CVS stenosis, and IJV stenosis, with the aim of providing a valid, practical reference for clinicians.

Emerging Role of Neutrophils in the Thrombosis of Chronic Myeloproliferative Neoplasms

Thrombosis is a major cause of morbimortality in patients with chronic Philadelphia chromosome-negative myeloproliferative neoplasms (MPN). In the last decade, multiple lines of evidence support the role of leukocytes in thrombosis of MPN patients. Besides the increase in the number of cells, neutrophils and monocytes of MPN patients show a pro-coagulant activated phenotype. Once activated, neutrophils release structures composed of DNA, histones, and granular proteins, called extracellular neutrophil traps (NETs), which in addition to killing pathogens, provide an ideal matrix for platelet activation and coagulation mechanisms. Herein, we review the published literature related to the involvement of NETs in the pathogenesis of thrombosis in the setting of MPN; the effect that cytoreductive therapies and JAK inhibitors can have on markers of NETosis, and, finally, the novel therapeutic strategies targeting NETs to reduce the thrombotic complications in these patients.

Low prevalence of JAK2 V617F mutation in patients with thrombosis and normal blood counts: a retrospective impact study

To determine the prevalence of the V617F Janus Kinase 2 (JAK2) mutation in patients with thrombosis without other biological signs of underlying myeloproliferative neoplasm (MPN) and identify associated risk factors for thrombosis. Over a 10-year period, data were collected from patients with thrombotic events and who had also been screened for the V617F JAK2 mutation. Patients with signs of underlying MPN, such as haematocrit levels ≥ 50% and/or platelet counts ≥ 450 × 10⁹/L and/or splanchnic thrombosis were excluded from the study. Of 340 patients fulfilling inclusion criteria, JAK2 mutation was found in 9 (2.65%), the allele burden being at least 2% in 4 (1.1%). Upon follow-up, MPN was diagnosed in the latter 4. Univariate analysis of the whole cohort showed that age (54 ± 15 vs. 64 ± 13, p = 0.027), platelet count (317 ± 111 vs. 255 ± 75, p = 0.017), C-reactive protein level > 5 mg/L (OR 7.29, p = 0.014), and splenomegaly (OR 54.5, p = 0.0002) were significantly associated with JAK2 mutation. There was also a trend for an increased risk of cerebral venous thrombosis (OR 6.54, p = 0.064). Logistic regression confirmed a significant association between splenomegaly and JAK2 mutation (OR 43.15 [95%CI, 3.05-610.95], p = 0.0054). The V617F JAK2 mutation is rarely found in patients with thrombotic events without overt MPN. Splenomegaly, however, is a statistically and clinically relevant indicator of a potential JAK2 mutation in patients with non-splanchnic thrombotic events. Such patients should require further assessment and a close follow-up.

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.

[Somatic mutation of the V617F JAK2 gene in patients of the cardiovascular diseases]

The JAK2 V617F somatic mutation is one of the most frequent markers of CHIP (clonal hematopoiesis of indeterminate potential). CHIP is characterized by the presence of a myeloid cells clone in peripheral blood in the absence of the sufficient reasons to diagnose the hematologic disease. The CHIP is proposed as a potential independent risk factor for vascular pathology. The aim of this study is to identify carriers of JAK2 V617F mutation among patients admitted for planned hospitalization at the Federal Center of Cardiovascular Surgery of Krasnoyarsk.

MATERIALS AND METHODS

The study included 930 venous blood samples. JAK2 V617F mutation was detected by using the allele - specific real time polymerase chain reaction.

RESULTS

JAK2 V617F mutation was detected in 15 (1.6%) patients, but only two of them had blood cell count that could cause a hematological disease to be suspected.

CONCLUSION

The inclusion of the JAK2 V617F mutation detection in the complex of laboratory tests of the cardiovascular patients can facilitate the timely identification of patients with increased thrombotic risk, as well as the timely diagnosis of myeloproliferative diseases.

V617F-independent upregulation of JAK2 gene expression in patients with inflammatory bowel disease

BACKGROUND

Inflammatory bowel disease (IBD) is one of the most important immune-mediated disorders of the gastrointestinal tract. Besides, IBD is associated with numerous extraintestinal complications such as venous thromboembolism (VTE), an important risk factor for vascular complications, which results in the increased morbidity and mortality. The JAK2 (Janus kinase 2) V617F mutation is a well-known point mutation which is involved in the pathogenesis of IBD, and VTE. Therefore, the aims of this study were to evaluate expression of JAK2 and association of V617F mutation in JAK2 of Iranian patients with IBD.

METHODS

Two hundred and forty-six patients with IBD (209 UC and 37 CD) and 206 healthy controls were enrolled in this study. The genomic DNA and total RNA were extracted from peripheral blood mononuclear cells (PBMCs). Then, the JAK2 V617F mutation detection was performed using the restriction fragment length polymorphism (RFLP) method. In addition, the JAK2 mRNA expression was evaluated using a quantitative polymerase chain reaction (q-PCR) using the SYBR Green assay.

RESULTS

There was no association of V61F mutation in patients with IBD with or without thrombosis compared with healthy control. However, the relative mRNA expression of JAK2 was significantly upregulated in patients with IBD in comparison with healthy control (P < 0.0001). In addition, the JAK2 mRNA expression was significantly decreased in patients with IBD having thrombosis compared with those without thrombosis ( P < 0.0001).

CONCLUSIONS

Taken together our findings suggested that JAK2 V61F-independent upregulation of JAK2 mRNA expression in patients with IBD. Moreover, despite the absence of JAK2 V617F mutation in patients with IBD, the increased gene expression of JAK2 can be explained by another molecular mechanism such as regulation of gene expression at the transcriptional level which may play crucial roles in the pathogenesis of IBD.

Prognostic value of JAK2V617F mutation in pseudotumor cerebri associated with cerebral venous sinus thrombosis

OBJECTIVES

To examine the clinical characteristics and prognosis of cerebral venous sinus thrombosis (CVST) that presented as pseudotumor cerebri (PTC) patients with JAK2V617F mutation.

METHODS

Medical records of all consecutive patients that presented with PTC and a JAK2V617F mutation who were treated were retrospectively reviewed. Data regarding demographics and ocular presenting symptoms and signs, neurological signs, hematological factors treatment, and prognosis were collected.

RESULTS

The most common presenting symptoms were headache (5 patients, 83.3%) and visual obscurations (5 patients, 83.3%). CVST of the sagittal sinus and sigmoid sinus were the most common site of thrombus. Platelet count and hemoglobin count were higher than normal during follow-up. There was significant change in the disk edema degree as well as decline in retinal nerve fiber layer (RNFL) thickness (P < 0.001, P < 0.001, Matched pairs). There was no significant change in visual acuity (VA) or mean deviation (MD) during follow-up (P = 0.95, 0.64, respectively, Matched pairs).

CONCLUSIONS

Pseudotumor cerebri resulting from CSVT in our patients with JAK2V617F mutation was frequent in young patients and needed medical and surgical treatment, without improvement in visual functions and in third caused poor visual outcome. Therefore, we believe that a screening test for JAK2V617F mutation should be considered for patients with CVST without known risk factor presenting with PTC, especially when sagittal sinus or sigmoid sinus involvement or thrombocytosis or high hemoglobin are found upon presentation. This might lead to more aggressive management which may improve the visual prognosis of those young patients.

Cerebral venous sinus thrombosis

The cerebral venous system is an unusual site of thrombosis, with a particularly high incidence in young adults. This incidence has increased in past decades because of the improvement of neuroradiological techniques. Risk factors for cerebral venous sinus thrombosis overlap with those of other venous thromboembolism sites; however, some are specific for this particular anatomical district. Prognosis is favorable in most cases if diagnosis is made rapidly and treatment is promptly initiated, even if acute complications or chronic invalidity still occur in a quarter of patients. The mainstay of treatment is anticoagulation, which is necessary in order to block clot propagation and obtain recanalization. Intracranial bleeding does not contraindicate anticoagulation. Endovascular procedures are reserved for patients with a particularly severe presentation or rapidly declining neurological symptoms despite appropriate anticoagulation, although data from clinical trials are lacking. Specifically, this review addresses the epidemiology, clinical presentation and course, risk factors, and treatment of cerebral venous sinus thrombosis, with a special focus on the pediatric population.

Thrombin-Activatable Fibrinolysis Inhibitor Polymorphisms and Cerebral Venous Thrombosis in Mexican Mestizo Patients

Thrombin-activatable fibrinolysis inhibitor (TAFI) gene polymorphisms have been proposed as a predisposing factor for cerebral venous thrombosis (CVT). We analyzed the association between CVT and TAFI single-nucleotide polymorphisms (rs3742264, rs2146881, and rs1926447) compared to healthy controls. Mexico Mestizo confirmed cases with CVT and age- and sex-matched controls with no history of venous thrombotic events were recruited from July 2006 to July 2015. Demographic, clinical, and imaging information was included in the analysis. Genotyping single-nucleotide polymorphisms were performed by allele-specific polymerase chain reaction. Allelic univariate analysis, haplotype association, and Hardy-Weinberg equilibrium were assessed. A total of 113 CVT cases (94 females [83.2%]; median age 35 years [interquartile range 27-43 years]) and 134 age- and sex-matched controls were included. The main risk factors for CVT were pregnancy/puerperium (30.9%), oral contraceptive use (19.5%), and hereditary thrombophilia (7.1%). We found no significant association for heterozygous and homozygous models for rs3742264 ( P = .30 and P = .69, respectively), rs2146881 ( P = .90 and P = .17, respectively), or rs1926447 ( P = .40 and P = .52, respectively) compared to controls; these findings were consistent in subgroup and haplotype analyses. In conclusion, TAFI rs3742264, rs2146881, and rs1926447 polymorphisms do not increase the risk of CVT in comparison to healthy controls.

Risk of recurrence of unusual site venous thromboembolism

The term unusual site venous thrombosis defines uncommon clinical manifestations of venous thromboembolism occurring in sites different from the lower limbs or the lungs, with peculiar pathophysiological features and clinical history. Information on long-term outcomes of unusual site thrombosis is generally scant, because most studies are small and usually retrospective.

Recurrence rate of cerebral vein thrombosis is about 2/100 patient-years; the only identified predisposing factors have been male gender and personal history of thrombosis. Retinal vein occlusion showed a recurrence in the same eye of 2.5% and in the fellow eye of 11.9% within four years. Hypercholesterolemia, hypertriglyceridaemia and hyperhomocysteinaemia were significantly associated with recurrent events. Recurrence rates of splanchnic vein thrombosis are difficult to estimate given the heterogeneity of patient populations; higher recurrence rates are reported in the cirrhotic population (from 27% to 38.5%). Hormone therapy, myeloproliferative neoplasm or other prothrombotic states, and absence of anticoagulant therapy emerged as independent prognostic factors. Future studies should aim at better assessing the risk of recurrence in different patients subgroups and at identifying more accurate prognostic markers.

Approach to thrombosis at unusual sites: Splanchnic and cerebral vein thrombosis

Splanchnic vein thrombosis (SVT) and cerebral vein thrombosis (CVT) are two manifestations of unusual site venous thromboembolism (VTE). SVT includes thrombosis in the portal, mesenteric or splenic veins, and the Budd-Chiari syndrome. CVT encompasses thrombosis of the dural venous sinuses and thrombosis of the cerebral veins. Unusual site VTE often represents a diagnostic and therapeutic challenge because of the heterogeneity in clinical presentation, the limited evidence available in the literature on the acute and long-term prognosis of these diseases, and the lack of large randomized controlled trials evaluating different treatment options. This narrative review describes the approach to patients with SVT or CVT by examining the diagnostic process, the assessment of potential risk factors and the appropriate anticoagulant treatment.

Should We Screen for Janus Kinase 2 V617F Mutation in Cerebral Venous Thrombosis?

BACKGROUND

The presence of Janus Kinase 2 (JAK2) V617F mutation represents a major diagnostic criterion for detecting myeloproliferative neoplasms (MPN) and even in the absence of overt MPN, JAK2 V617F mutation is associated with splanchnic vein thrombosis. However, the actual prevalence and diagnostic value of the JAK2 V617F mutation in patients with cerebral venous thrombosis (CVT) are not known. The aims of this study were to assess the prevalence of JAK2 V617F mutation in a large group of consecutive CVT patients, to detect clinical, biological, and radiological features associated with the mutation, and to determine the long-term venous thrombosis recurrence rate in CVT patients with JAK2 mutation but without overt MPN in order to recommend the best preventive treatment.

METHODS

This was a prospective study conducted on consecutive patients with a first-ever radiologically confirmed CVT. JAK2 V617F mutation analysis was assessed in all the study subjects. JAK2 V617F-positive patients were followed up to detect new venous thrombotic events.

RESULTS

Of the 125 included subjects, 7 were found to have JAK2 V617F mutation (5.6%; 95% CI 2.3-11.2). Older age (p = 0.039) and higher platelet count (p = 0.004) were independently associated with JAK2 V617F positivity in patients without overt MPN. During a mean follow-up period of 59 (SD 46) months, 2 JAK2 V617F-positive patients presented with 4 new venous thromboembolic events.

CONCLUSIONS

Screening for the JAK2 V617F mutation in CVT patients seems to be useful even in the absence of overt MPN and/or in the presence of other risk factors for CVT because of its relatively high prevalence and the risk of thrombosis recurrence.

Ten years of cerebral venous thrombosis: male gender and myeloproliferative neoplasm is associated with thrombotic recurrence in unprovoked events

Cerebral venous thrombosis (CVT) is a rare venous thrombotic event. We review our local experience in the management of CVT in comparison to other venous thromboembolism (VTE) with specific focus on risk factors for thrombotic recurrence. Retrospective evaluation of consecutive CVT presentations from January 2005 to June 2015, at two major tertiary hospitals in Northeast Melbourne, Australia. This population was compared to a separate audit of 1003 consecutive patients with DVT and PE. Fifty-two patients (30 female, 22 male) with a median age of 40 (18-83) years, presented with 53 episodes of CVT. Twenty-nine episodes (55 %) were associated with an underlying risk factor, with hormonal risk factors in females being most common. The median duration of anticoagulation was 6 months with 11 receiving life-long anticoagulation. Eighty-one percent had residual thrombosis on repeat imaging, which was not associated with recurrence at the same or distant site. Nine (17 %) had CVT-related haemorrhagic transformation with two resultant CVT-related deaths (RR 22.5; p = 0.04). All three VTE recurrences occured in males with unprovoked events (RR 18.2; p = 0.05) who were subsequently diagnosed with myeloproliferative neoplasm (MPN). Compared to the non-cancer VTE population, non-cancer CVT patients were younger, had similar rate of provoked events and VTE recurrence, although with significantly higher rate of MPN diagnosis (RR 9.30 (2.29-37.76); p = 0.002) CVT is a rare thrombotic disorder. All recurrences in this audit occurred in male patients with unprovoked events and subsequent diagnosis of MPN, suggesting further evaluation for MPN may be warranted in patients with unprovoked CVT.

Cancer associated thrombosis: risk factors and outcomes

Deep vein thrombosis of the leg and pulmonary embolism are frequent diseases and cancer is one of their most important risk factors. Patients with cancer also have a higher prevalence of venous thrombosis located in other parts than in the legs and/or in unusual sites including upper extremity, splanchnic or cerebral veins. Cancer also affects the risk of arterial thrombotic events particularly in patients with myeloproliferative neoplasms and in vascular endothelial growth factor receptor inhibitor recipients. Several risk factors need to interact to trigger thrombosis. In addition to common risk factors such as surgery, hospitalisation, infection and genetic coagulation disorders, the thrombotic risk is also driven and modified by cancer-specific factors including type, histology, and stage of the malignancy, cancer treatment and certain biomarkers. A venous thrombotic event in a cancer patient has serious consequences as the risk of recurrent thrombosis, the risk of bleeding during anticoagulation and hospitalisation rates are all increased. Survival of cancer patients with thrombosis is worse compared to that of cancer patients without thrombosis, and thrombosis is a leading direct cause of death in cancer patients.

Towards the genetic basis of cerebral venous thrombosis-the BEAST Consortium: a study protocol

INTRODUCTION

Cerebral venous thrombosis (CVT) is a rare cerebrovascular condition accounting for <1% of all stroke cases and mainly affects young adults. Its genetic aetiology is not clearly elucidated.

METHODS AND ANALYSIS

To better understand the genetic basis of CVT, we have established an international biobank of CVT cases, Biorepository to Establish the Aetiology of Sinovenous Thrombosis (BEAST) which aims to recruit highly phenotyped cases initially of European descent and later from other populations. To date we have recruited 745 CVT cases from 12 research centres. As an initial step, the consortium plans to undertake a genome-wide association analysis of CVT using the Illumina Infinium HumanCoreExome BeadChip to assess the association and impact of common and low-frequency genetic variants on CVT risk by using a case-control study design. Replication will be performed to confirm putative findings. Furthermore, we aim to identify interactions of genetic variants with several environmental and comorbidity factors which will likely contribute to improve the understanding of the biological mechanisms underlying this complex disease.

ETHICS AND DISSEMINATION

BEAST meets all ethical standards set by local institutional review boards for each of the participating sites. The research outcomes will be published in international peer-reviewed open-access journals with high impact and visibility. The results will be presented at national and international meetings to highlight the contributions into improving the understanding of the mechanisms underlying this uncommon but important disease. This international DNA repository will become an important resource for investigators in the field of haematological and vascular disorders.

Genetic Risk Factors of Venous Thromboembolism in the East Algerian Population

Many genetic risk factors have been identified for causing venous thromboembolism (VTE). Most of them affect the function of natural anticoagulant pathways, particularly the protein C system, although recent studies suggest a role of components of the hematopoietic pathway in the etiology of venous thrombosis. In this case–control study, we aimed to determine the frequency of prothrombin G20210A and factor V Leiden (FVL) G1691A polymorphisms and protein C, protein S, and antithrombin III deficiencies in the East Algerian population and to investigate whether these genetic factors are associated with VTE. On the other hand, our study tends to evaluate the status of JAK2V617F and calreticulin (CALR) mutations among these cases. The participants consisted of 121 cases with VTE and 146 healthy controls. Polymorphisms of FVL G1691A and prothrombin G20210A were genotyped by polymerase chain reaction (PCR) restriction fragment length polymorphism. JAK2-V617F and calreticulin mutations were analyzed by quantitative PCR and PCR followed by capillary electrophoresis sequencing, respectively. Protein C, protein S, and antithrombin levels were determined and then hereditary deficiencies were identified. Of all cases and controls, none was a carrier of the antithrombin III deficiency, prothrombin gene G20210A, and CALR mutations. Only 1 case reported having a positive JAK2 mutation (mutant allele burden was 15%). The FVL mutation (GA/AA) was found in 14 (11.6%) cases and 2 (1.4%) controls and it was significantly different between both the groups ( P = .001). Deficiencies of protein S and protein C were detected in 17 (18.8%) cases. The univariate analysis resulted in a significant impact of FVL (odds ratio [OR] = 9.4, 95% confidence interval [CI] = 2.1-42.3; P = .003) and of protein S deficiency (OR = 16.9, 95% CI =2.1-132.8, P = .007) on the VTE status. Both factors stayed significant after adjustment for sex and age. The OR of the protein C deficiency was slightly elevated (OR = 6.4, 95% CI = 0.7-55.5), but it did not reach the level of statistical significance ( P = .091), and it was therefore not considered as a risk factor. In conclusion, coagulant factor V gene G1691A mutation and protein S deficiency constitute important genetic risk factors in patients with VTE in Eastern Algeria. The somatic mutation of JAK2 V617F and CALR mutations are less frequent causes of VTE, thus routine testing for these mutations is not recommended.

[Thrombosis of the cerebral veins in gynecological practice]

The review presents literature data on the risk factors of cerebral venous thrombosis (CVT), a rare life threatening disorder. Currently, the diagnosis of CVT is made more often due to the possibility of using neuroimaging methods of cerebral structures. Pregnancy, postpartum period, use of oral contraceptives are risk factors of CVT. A role of thrombophilia, in particular Factor V Leiden mutations and the prothrombin G20210A polymorphism, in the CVT pathogenesis is confirmed. The development of CVT is an example of the interaction between persistent risk factors increasing the likelihood of thrombotic complications and acquired risk factors. A focal neurological deficit during pregnancy, delivery and postpartum period is the best indicator of CVT diagnosis. Possibilities of the use of anticoagulants in treatment and prevention of CVT are analyzed.

Head trauma is the major risk factor for cerebral sinus-vein thrombosis

BACKGROUND

Cerebral sinus vein thrombosis (CSVT) is a rare disease with significant neurological sequelae and high mortality rate. Incidence of CSVT diagnosis in the western world has increased despite the reduced occurrence of infections.

AIM

To identify risk factors that may explain the predisposition to site specific thrombosis.

METHODS

Ninety consecutive patients diagnosed with acute CSVT in tertiary hospital. As a control group we used the data extracted from the National Trauma Registry and Healthcare Services.

RESULTS

Trauma history up to one month prior to diagnosis of CVST was found in 13 (14%) patients. Six patients had skull fractures, the others had blunt trauma. The overall SMR was 941 (p<0.0001); the separate results for men and women were 1206 and 543, respectively. Infections confined to the head and neck in 7% of the cases and brain tumor were observed in 8%. At the time of CVST, 23 of 50 (46%) women had a hormonal risk factor. The SMR for OC use was 1.63 (p=0.0298). Prothrombotic polymorphisms were detected in 16 of 63 (25.4%) patients who were tested for factor V Leiden and prothrombin G20210A mutation (OR=3.47, p=0.002) in comparison to 49% in DVT patients (OR=9.95, p<0.0001).

CONCLUSIONS

Assessment for CVST in patients with recent trauma and headache even after intact head CT is required. The other risk factors, such as hormone related and prothrombotic polymorphisms, were not specific just for CVST and the latter play a lesser role in CVST than in DVT.

A Case of Recurrent Ischemic Stroke Involving Subacute, Progressive Intracranial Cerebral Arterial Sclerosis Prior to Diagnosis with JAK2-mutated Polycythemia Vera

CASE REPORT

A 58-year-old man presenting with no vascular risk factors visited our hospital with right hemiparesis and total aphasia. Diffusion-weighted magnetic resonance imaging of the brain showed multiple hyperintensities in watershed distributions in the left hemisphere. Magnetic resonance angiography (MRA) revealed stenosis of the middle cerebral artery, despite normal MRA findings 2 months prior. One year after the first stroke, the patient experienced a recurrent ischemic stroke involving the left anterior choroidal artery, pulmonary embolism, and deep venous thrombosis. After the recurrent stroke event, hemoglobin levels increased gradually. Two years after the first stroke, a JAK2V-617F mutation was detected.

CONCLUSION

Our report suggests that progressive intracranial arterial sclerosis and venous thrombosis of undetermined etiologies could be several initial symptoms of polycythemia vera.

Cerebral thrombosis and myeloproliferative neoplasms

Myeloproliferative neoplasms (MPN) are acquired clonal disorders characterized by the proliferation of bone marrow myeloid cells. Different somatic mutations have been recently associated with MPN, the most common being JAK-2 V617F. Among MPN, polycythemia vera and essential thrombocythemia are particularly associated with an increased risk to develop thrombotic complications, either arterial or venous. Cerebrovascular events (stroke and transient ischemic attacks) are prevalent, accounting for approximately two-thirds of all events. Also cerebral vein thrombosis can complicate MPN and can be the first manifestation of the disease. Risk factors for thrombosis in patients with MPN are related or unrelated to the disease. Among the former there are cellular risk factors, such as increased white blood cell counts, vascular cell activation, endothelial dysfunction, and plasmatic risk factors, such as increased plasma viscosity, reduced levels of protein S, increased thrombin generation. The latter include increased age and previous thrombotic events. In addition, common cardiovascular risk factors (smoking, hypertension, diabetes, dyslipidemia, obesity) contribute to the pathogenesis of arterial events, whereas circumstantial risk factors (particularly oral contraceptive use and pregnancy/puerperium) to that of venous events. Primary prevention of arterial thrombosis with antiplatelet therapy is warranted in the majority of patients with MPN, whereas primary prevention of venous thrombosis is limited to anticoagulant prophylaxis during high-risk situations. Secondary prevention includes long-term antiplatelet therapy for arterial and short- or long-term anticoagulant therapy for venous thrombosis, depending on the risk factors present at the first event.

Cerebral vein thrombosis in patients with Philadelphia-negative myeloproliferative neoplasms. An European Leukemia Net study

To investigate the characteristics and clinical course of cerebral vein thrombosis (CVT) in patients with myeloproliferative neoplasms (MPN) we compared 48 patients with MPN and CVT (group MPN-CVT) to 87 with MPN and other venous thrombosis (group MPN-VT) and 178 with MPN and no thrombosis (group MPN-NoT) matched by sex, age at diagnosis of MPN (±5 years) and type of MPN. The study population was identified among 5,500 patients with MPN, from January 1982 to June 2013. Thrombophilia abnormalities were significantly more prevalent in the MPN-CVT and MPN-VT than in MPN-NoT group (P = 0.015), as well as the JAK2 V617F mutation in patients with essential thrombocythemia (P = 0.059). Compared to MPN-VT, MPN-CVT patients had a higher rate of recurrent thrombosis (42% vs. 25%, P = 0.049) despite a shorter median follow-up period (6.1 vs. 10.3 years, P = 0.019), a higher long-term antithrombotic (94% vs. 84%, P = 0.099) and a similar cytoreductive treatment (79% vs. 70%, P = 0.311). The incidence of recurrent thrombosis was double in MPN-CVT than in MPN-VT group (8.8% and 4.2% patient-years, P = 0.022), and CVT and unprovoked event were the only predictive variables in a multivariate model including also sex, blood count, thrombophilia, cytoreductive, and antithrombotic treatment (HR 1.97, 95%CI 1.05-3.72 and 2.09, 1.09-4.00, respectively).

Cerebral venous thrombosis-a primer for the haematologist

Cerebral venous thrombosis (CVT) is a condition that can affect all age groups and can often be difficult to diagnose and treat. The difficulties in diagnosis are mainly due to the non-specific presenting features of CVT, which can range from isolated headache and visual or auditory problems, to serious symptoms such as hemiparesis and coma. Therefore, it can present to various specialists including general physicians, obstetricians and neurologists. In recent years, more widespread use of cerebral imaging has led to the diagnosis being made more often. Since thrombosis is the key component, haematologists are consulted in the management of these patients including for identification of a causative factor for CVT. In this regard, the pivotal International Study on Cerebral Vein and Dural Sinus Thrombosis (ISCVT) has shed more light on its epidemiology and management options. This review aims to provide guidance to haematologists when faced with a patient with CVT, based on the currently available evidence.

Budd-Chiari Syndrome in a Patient with JAK-2 V617F and Factor V G1691A Mutations

Myeloproliferative neoplasms (MPN) are considered a risk factor for Budd-Chiari syndrome (BCS). The current classification of MPN by the World Health Organization is based on the presence of JAK-2 V617F somatic mutation, which is present in 40 to 60% of patients with BCS. Factor V Leiden mutation is found in around 53% of patients with BCS, representing the most common prothrombotic disease associated with the disorder. We describe a 48-year old woman with a past medical history of deep venous thrombosis in the left upper extremity and one episode in both lower extremities, one episode of transient ischaemic attack and essential thrombocythemia, who presented with jaundice, ascites and hepatomegaly. Budd-Chiari syndrome was diagnosed based on findings on Doppler ultrasound and liver biopsy. Doppler ultrasound showed narrowness of hepatic veins and inferior vena cava in its hepatic portion, diffuse echotexture and portal hypertension. Liver biopsy showed congestion of sinusoids and portal fibrosis. The patient was found to be a heterozygous carrier of Factor V and homozygous wild type G20210A prothrombin mutations. The JAK-2 V617F mutation was detected by allele-specific polymerase chain reaction (AS-PCR). The association of these mutations is rare, with only a few cases reported in the literature. The patient was treated with oral anticoagulation and antiplatelets with good results and proper follow-up. In conclusion, due to the possible coexistence of multiple prothrombotic factors in patients with Budd-Chiari syndrome, the approach to these patients must be focussed on searching for multiple factors and should include the JAK-2 V617F mutation.

Cerebral venous thrombosis and myeloproliferative neoplasms: results from two large databases

INTRODUCTION

Myeloproliferative neoplasms (MPNs) include polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF). Patients with MPNs are prone to develop arterial and venous thrombosis either at diagnosis or during follow-up; in particular splancnic vein is strongly associated with MPN. Conversely, presence of MPN is uncommon in patients with deep vein thrombosis of the lower extremities and with pulmonary embolism. Only few studies with conflicting results have evaluated the prevalence of an underlying MPN in patients with cerebral venous thrombosis (CVT), and limited evidence exists on the incidence of CVT in patients with established MPN.

METHODS

We assessed the frequency of MPNs in a series of 706 patients with cerebral vein thrombosis (CVT) and the frequency of CVT in a cohort of 2,143 MPNs patients.

RESULTS

Twenty-seven CVT patients (3.8%) were diagnosed with MPN: 9 before CVT (1.3%), 4 concomitantly (0.6%), and 14 after CVT (2.0%). Nine CVT cases (0.4%) were diagnosed in the MPN cohort, with a slightly higher frequency in PV (five of 735, 0.7%) than in ET (three of 964, 0.3%) and in PMF (one of 444, 0.2%).

CONCLUSION

Considering the analyses of these databases jointly, the results obtained suggest a weak association between CVT and MPNs and ultimately suggest that a thorough investigation looking for an underlying MPN may not be warranted in all the patients with CVT without overt myeloproliferative features.

Cerebral vein thrombosis

The estimated annual incidence of cerebral vein thrombosis (CVT) is 3 to 4 cases per million in adults and 7 cases per million in neonates. Among the commonest risk factors there are oral contraceptive use, pregnancy and puerperium that make CVT more frequent in women than in men. Cerebral tumors, infections and traumas are less encountered local risk factors. In 15-20% of patients CVT remains unprovoked. Coagulation abnormalities causing thrombophilia, as well as hyperhomocysteinemia, are worthy to be investigated in patients with CVT. Rarely CVT can be the first clinical manifestation of a myeloproliferative neoplasm. The recurrence rate of CVT is low, but venous thromboembolism in the common sites (lower-limb deep vein thrombosis or pulmonary embolism) can recur, particularly in patients with a first idiopathic CVT. Early diagnosis and anticoagulant treatment reduce morbidity of CVT and improve survival, although the optimal duration of anticoagulant treatment is not well established.

Splanchnic vein thrombosis in myeloproliferative neoplasms

Splanchnic vein thrombosis (SVT) is one of the most important complications of myeloproliferative neoplasms (MPN). Although MPN are common causes of SVT, the pathophysiological mechanisms underlying this predisposition, their epidemiology and natural history are not fully understood. Studies have concentrated on the generalized prothrombotic environment generated by MPN and their relationship with abnormal blood counts, thereby furthering our knowledge of arterial and venous thrombosis in this population. In contrast, there are few studies that have specifically addressed SVT in the context of MPN. Recent research has demonstrated in patients with MPN the existence of factors increasing the risk of SVT such as the presence of the JAK2 V617F mutation and its 46/1 haplotype. Features unique to the circulating blood cells, splanchnic vasculature and surrounding micro-environment in patients with MPN have been described. There are also abnormalities in local haemodynamics, haemostatic molecules, the spleen, and splanchnic endothelial and endothelial progenitor cells. This review considers these important advances and discusses the contribution of individual anomalies that lead to the development of SVT in both the pre-neoplastic and overt stage of MPN. Clinical issues relating to epidemiology, recurrence and survival in these patients have also been reviewed and their results discussed.

Thrombotic complications of myeloproliferative neoplasms: risk assessment and risk-guided management

Philadelphia-negative myeloproliferative neoplasms are considered to be acquired thrombophilic states. Thromboses, both arterial and venous (not rarely in unusual sites), are often the initial events leading to the diagnosis. After diagnosis, the yearly incidence of thrombotic events is highly variable, and ranges from approximately 1% to 10%. The identification of patients at risk who may benefit from antithrombotic therapy remains a challenge, and it is currently based on age and history of thrombotic events. However, the predictive value of these clinical characteristics is rather limited. Few prospective studies and even fewer interventional randomized studies are available, and there are no studies designed to formally validate the use of risk stratification. The implementation of laboratory parameters such as leukocytosis and/or the JAK2 V617F mutation into a scoring system may be of interest. The mechanisms at work leading to thrombosis remain largely speculative, but are likely to be complex and multifactorial, with a prominent role of cell-cell interactions, mostly owing to qualitative changes. The long-term treatment options to prevent thrombosis are, schematically, aspirin alone as primary prevention for the low-risk patients, and cytoreduction combined with aspirin for the other patients. In very low-risk young essential thrombocythemia patients, abstention can even be considered. The optimal duration of anticoagulation after a thrombotic event is not established. All antithrombotic therapies should be balanced with the hemorrhagic risk, which can also be increased in these patients.

Cerebral sinus-venous thrombosis

Cerebral sinus-venous thrombosis (CSVT) is a rare life-threatening disease with an estimated annual incidence of 3-4 cases per million in adults and 7 cases per million in neonates. Brain tumors, cerebral infections and traumas are local risk factors for CSVT, but the commonest encountered risk factors are oral contraceptive use, pregnancy and puerperium that make the disease predominant in female sex. In 15-20 % of patients, the disease remains unprovoked, i.e., occurring in the absence of predisposing factors. Thrombophilic abnormalities either inherited [deficiency of the natural anticoagulant proteins antithrombin, protein C or protein S, mutations in the factor V gene (factor V Leiden) or prothrombin gene (prothrombin G20210A)] or acquired (antiphospholipid antibodies) are worthy to be investigated in patients with CSVT, as well as hyperhomocysteinemia. In a small proportion of patients, CSVT is the first manifestation of a myeloproliferative neoplasm. The proportion of patients with recurrent CSVT is low, but venous thromboembolism (deep vein thrombosis in the lower limbs or pulmonary embolism) can develop particularly in patients with a first idiopathic CSVT. In the past decade, there has been increasing evidence that early diagnosis and anticoagulant treatment reduce morbidity of CSVT and improve survival. However, the optimal duration of anticoagulant treatment is not well established, because limited information is available on the rate of CSVT recurrence after anticoagulant discontinuation.