Original Paper Cerebrovasc Dis 2017;44:97–104 DOI: 10.1159/000471891
Received: November 23, 2016 Accepted: March 20, 2017 Published online: June 14, 2017
Should We Screen for Janus Kinase 2 V617F Mutation in Cerebral Venous Thrombosis? Matthias Lamy b Paola Palazzo a, b Pierre Agius b Jean Claude Chomel c Jonathan Ciron b Aline Berthomet b Paul Cantagrel b Julia Prigent b Pierre Ingrand d Mathieu Puyade e Jean-Philippe Neau b a
Department of Neurology, S. Giovanni Calibita-Fatebenefratelli Hospital, Rome, Italy; b Department of Neurology, Laboratory of Cancer Biology, d Clinical Investigation Center INSERM, and e Department of Oncology-Hematology and Cell Therapy, Poitiers University Hospital, Poitiers, France c
Abstract 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 longterm 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 V617Fpositive patients were followed up to detect new venous
© 2017 S. Karger AG, Basel E-Mail [email protected] www.karger.com/ced
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 followup 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. © 2017 S. Karger AG, Basel
Introduction
Cerebral venous thrombosis (CVT) is a rare and lifethreatening disease that affects about 3–5 people per million and accounts for 0.5% of all strokes [1, 2]. The etiology of CVT is multifactorial, involving genetic and acquired factors. Diverse conditions have been recognized
P.P. and M.L. equally contributed to the study.
Paola Palazzo Department of Neurology, Poitiers University Hospital 2 rue de la Milétrie FR–86021 Poitiers Cedex (France) E-Mail ppalazzo @ hotmail.it paola.palazzo @ chu-poitiers.fr
Downloaded by: Glasgow Univ.Lib. 130.209.6.61 - 9/6/2017 3:41:48 PM
Keywords Cerebral venous thrombosis · Anticoagulation · Coagulation abnormalities in cerebrovascular diseases · Hematology
Table 1. Prevalence of JAK2 V617F mutation in patients with cerebral venous thrombosis without overt myeloproliferative disorders Authors
Year of publication
Country
Setting
Subjects, n JAK2 V617F-positive subjects, n (%)
Colaizzo et al. [9]
2007
Italy
Thrombosis center
Remacha et al. [33]
2007
Spain
Department of hematology
2007
Italy
De Stefano et al. [10, 25]
2007, 2008
Pardanani et al. [35]
45
0 (0)
6
0 (0)
Division of hematology
13
0 (0)
Italy
Institute of hematology
48
3 (6.3)
2008
US
Division of hematology
7
1 (14)
Bellucci et al. [20]
2008
France
Hematology and neurology services
87
1 (1.1)
Xavier et al. [21]‡
2008
Brazil
Hematology service
44
0 (0)
Koopman et al. [34]§
2009
Netherlands Department of neurology and department of hematology
56
0 (0)
2010
India
Institute of immunohematology
70
2 (3)
Passamonti et al. [32]
2012
Italy
Hematology center
146
4 (2.7)
De et al. [22]**
2012
India
Department of neurochemistry and neurology
372
22 (5.9)
France
Department of neurology
125
7 (5.6)
Rossi et al. [19]* †
Shetty et al. [36]| | #
††
Present study All patients
1,019
40 (3.9 95% CI 2.8–5.3)
* This study did not include patients with inherited or acquired thrombophilia or subjects with risk factors for thrombosis including malignancy, surgery, pregnancy, oestrogen consumption, liver failure, and nephrotic syndrome. † The study consisted of 52 CVT patients, including 4 CVT patients with overt MPN, of whom 3 had the JAK2 V617F mutation. The study did not include CVT patients with malignancy. ‡ None of the patients with CVT had infections, trauma, malignancies, or autoimmune diseases. § The series consisted of 59 CVT patients, including 3 CVT patients with overt MPN, of whom 2 had the JAK2 V617F mutation. | | This study did not include patients with overt cancer or liver cirrhosis. # The study consisted of 152 CVT patients, including 6 CVT patients with overt MPN, all with the JAK2 V617F mutation. ** The study did not include patients with CVT secondary to head trauma, invasive procedures, sepsis, neuroinfection, or malignancy. †† The study did not include patients with CVT secondary to head trauma, invasive procedures, or associated with cerebral vascular malformations.
98
Cerebrovasc Dis 2017;44:97–104 DOI: 10.1159/000471891
from 12 to 74% [7–16] with a mean prevalence of 32.7% [17]. This wide range of JAK2 mutation positivity could be explained by several factors, including heterogeneity in the inclusion criteria, small sample size, different sensitivities of the assays employed for the detection of the mutation, and the different types of biological samples used [18]. However, only a few studies have evaluated the prevalence of the JAK2 V617F mutation in patients with CVT, and they have demonstrated distinctly lower prevalence, ranging from 0 to 14% (Table 1) [9, 10, 19–23]. Therefore, the actual diagnostic value of JAK2 V617F assessment as part of the routine thrombophilia investigation in patients with CVT still needs to be addressed [18, 24, 25]. Hence, the purpose of this prospective study was to evaluate the prevalence of JAK2 V617F mutation in a large group of consecutive CVT patients without known mutation status and to subsequently assess this prevalence in a subgroup of CVT patients without hematologLamy et al.
Downloaded by: Glasgow Univ.Lib. 130.209.6.61 - 9/6/2017 3:41:48 PM
as risk factors for this disease; oral contraceptive intake and puerperium are associated with an increased risk for CVT in younger women, while infectious and chronic inflammatory diseases, cancer, and myeloproliferative neoplasms (MPN) as well as trauma are acquired predisposing conditions in men and women at any age. The Janus Kinase 2 (JAK2) V617F (c.1849G>T, p.Val617Phe, according to the Human Genome Variation Society) somatic gain-of-function mutation has been found to be associated with polycythemia vera, essential thrombocythemia, and primary myelofibrosis [3, 4]. Its presence is now considered to be a major diagnostic criterion for MPN [5, 6]. Venous thrombotic complications (splanchnic, cerebral, or deep vein thromboses) are an important concern in MPN patients and may reveal the disease. Several studies have focused on the prevalence of JAK2 V617F mutation in patients with venous thrombosis. In patients with splanchnic vein thrombosis and without overt MPN, JAK2 V617F positivity has ranged
Methods
ing to the manufacturer’s instructions. The G1849T transversion (corresponding to the V617F mutation) was detected either by multiplex ARMS (amplification refractory mutation system) PCR (period August 2005 to June 2012) or by real-time PCR (from July 2012). The multiplex ARMS PCR method was performed in a 2-tube format; tube 1 contained the wild-type forward primer (5′-AGCA TTTGGTTTTAAATTATGGAGTATGGG-3′, 800 nM) and tube 2 the mutation forward primer (5′-AGCATTTGGTTTTAAATTATGGAGTATGCT-3′, 800 nM). Both tubes also contained the outer forward primer (5′-TGCTGAAAGTAGGAGAAAGTGC-3′, 40 nM) and the common reverse primer (5′-ACTTCATTGCTTTCCTTTTTCAC-3′, 400 nM). Amplifications were carried out in 50 μL with 10 mM Tris-HCl (pH 8.3), 50 mM KCl, 2.5 mM MgCl2, 200 μM each deoxynucleotide triphosphate, and 2.5 units of AmpliTaqGoldDNA Polymerase (Life Technologies, Carlsbad, CA, USA). The PCR conditions consisted of a denaturation at 95 ° C for 5 min, followed by 35 cycles of denaturation at 94 ° C for 30 s, annealing at 60 ° C for 60 s, and extension at 72 ° C for 50 s. Based on serial dilution experiments, the sensitivity of the method was set at 5%. The JAK2 V617F mutation was later detected using a real-time PCR method. JAK2 wild type and V617F alleles were specifically amplified using the JAK2 MutaSearch Kit (Ipsogen, Marseille, France) according to the manufacturer’s protocol. This kit has a sensitivity of 1% (mutated alleles among total JAK2 alleles).
Study Population The study group comprised of consecutive patients with a firstever CVT who were hospitalized between January 2005 and December 2014 in the department of Neurology of our academic hospital. CVT diagnosis was confirmed by one of the following methods: brain CT-scan with CT venography, MRI with MR venography, or conventional angiography (for a few patients). Neuroimaging was analyzed using a blind-test method by 2 of us (J.-P.N. and M.L.) to confirm the diagnosis of CVT. Exclusion criteria were (i) inconclusive neuroimaging studies; (ii) CVT secondary to head trauma, invasive procedures, or associated with cerebral vascular malformations; (iii) previously known MPN and/or presence of JAK2 V617F mutation. Baseline demographic, clinical, and radiological data were recorded, including vascular risk factors and family history of vascular events, location of thrombosis, and clinical presentation. Women were considered to be on oral contraceptives if they had taken them up until a week before the thrombotic event. Puerperal CVT was diagnosed when CVT occurred during the first 4 weeks after childbirth. All subjects underwent a detailed neurological examination and complete hematologic and biochemical exams. Thrombophilia testing included DNA analysis for factor V Leiden and G20210A prothrombin mutations; functional assays and/or immunoassays for plasma antithrombin, protein C and protein S; and antiphospholipid antibodies (lupus anticoagulant, anticardiolipin, and anti-b2 glycoprotein I antibodies). JAK2 V617F mutation analysis was assessed in all the study subjects. In the presence of clinical and biological features suggestive of MPN, hematological evaluation was conducted to confirm the diagnosis according to international guidelines [26]. This study was approved by the local Ethics Committee and informed written consent was obtained from all patients. JAK2 V617F-positive patients were followed up on an annual basis by means of a neurological outpatient visit. If an in-person evaluation was not possible, alternative methods included a telephone interview of the patient or an interview with a relative or their general practitioner. Detection of the JAK2 V617F Mutation in Blood Samples Genomic DNA was extracted from peripheral whole blood samples using a BioSprint 15 workstation (Qiagen, Hilden, Germany) and the BioSprint 15 DNA blood kit (Qiagen), accord-
JAK2 V617F in CVT
Statistical Analysis The prevalence of JAK2 V617F mutation was estimated by an exact binomial 95% CI, and compared with a pooled estimate from literature using Fisher’s exact test. Univariate analysis compared patients with and without JAK2 V617F mutation using the nonparametric Mann-Whitney test for quantitative variables and Fisher’s exact test for qualitative variables. Variables with a univariate p value below 0.20 were retained to be entered into a multivariate logistic regression analysis. The final logistic model was obtained after performing a backward elimination procedure. All tests were considered significant at the 5% level. Analyses were performed with SAS 9.4 (Cary NC, USA).
Results
One hundred and forty patients with a first event of radiologically confirmed CVT fulfilling the previously mentioned criteria were hospitalized in our department from January 2005 to December 2014. Fifteen of them were excluded for informed consent refusal (n = 5), death in the acute phase before JAK2 mutation assessment (n = 7), a previously known JAK2 V617F mutation (n = 1), or an overt MPN, which was detected during the CVT diagnostic workup (n = 2). Of the 125 subjects included, 7 were found to have JAK2 V617F mutation (5.6%; 95% CI 2.3–11.2), while 118 were JAK2 V617F mutation-negative (Fig. 1). Characteristics of JAK2-positive patients are detailed in Table 2, while general, biological, and radiological data Cerebrovasc Dis 2017;44:97–104 DOI: 10.1159/000471891
99
Downloaded by: Glasgow Univ.Lib. 130.209.6.61 - 9/6/2017 3:41:48 PM
ical abnormalities suggestive of overt MPN. The second objective was to compare clinical, biological, and radiological features in 2 groups of patients with CVT (JAK2 V617F-positive without overt MPN and JAK2 V617Fnegative) in order to detect a subgroup at higher risk for JAK2 V617F mutation, which would specifically benefit from mutation assessment. The third objective was to determine the long-term prognosis of CVT patients with JAK2 mutation but without overt MPN concerning venous thrombosis recurrences in view of recommending the best preventive treatment.
Table 2. Patients with CVT and JAK2 V617F mutation ID No. Gender
Age at Risk factors at Hb, Ht, % Platelets, WBC, CVT, years the time of CVT g/dL ×103 mm3 ×mm3
Follow-up, VKA treatment months duration, months
Cytoreductive treatment
Venous thrombotic recurrence
Delay, months
1 2 3 4 5 6 7
30 72 49 76 62 60 77
122 5 93 25 110 7 97
Hydroxyurea Hydroxyurea Hydroxyurea, anagrelide Phlebotomy Hydroxyurea Hydroxyurea None
ST – – – 2 Recurrent CVT/PE – –
47
F F F F F F F
OC – – – – – DVT, ST
14.0 14.7 13.3 14.0 11.4 12.6 9.6
42.1 42.3 39.6 43.0 36.3 36.1 33.5
334 371 345 196 345 436 423
5,600 8,500 8,300 9,900 5,600 7,600 7,000
115 5 92 25 110 6 85
20*
CVT, cerebral venous thrombosis; OC, oral contraceptive; WBC, white blood cell; VKA, vitamin K antagonist; PE, pulmonary embolism; DVT, deep venous thrombosis; ST, splanchnic thrombosis. * Delay from the first CVT episode to the first new venous thrombotic recurrence.
140 CVT patients 7 died 5 refused consent 1 had known JAK2 mutation status 127 patients 2 had overt MPN 125 patients
7 JAK2 V617F-positive patients
118 JAK2 V617F-negative patients
Fig. 1. Flowchart of the study population.
100
Cerebrovasc Dis 2017;44:97–104 DOI: 10.1159/000471891
combination with interferon-alpha and a cytoreductive treatment (hydroxyurea) with the goal of complete hematological remission. When considering all studies, including the present one, which have evaluated JAK2 V617F prevalence in a total number of 1,019 CVT patients without an overt MPN, the overall prevalence was found to be 3.9% (95% CI 2.8–5.3). Similarly, taking into account the 11 previous studies, global prevalence was 3.7% (95% CI 2.5–5.2), which was slightly, though not significantly lower than the percentage of our study prevalence (p = 0.32).
Discussion
Since the time acquired V617F mutation in the JAK2 gene was identified as a common event of Philadelphia (Ph)-negative MPN, its association with an increased arterial and venous thrombotic risk has been widely studLamy et al.
Downloaded by: Glasgow Univ.Lib. 130.209.6.61 - 9/6/2017 3:41:48 PM
in patients with JAK2 V617F mutation (without overt MPN) and without JAK2 V617F mutation in univariate analysis are shown in Table 3. In multivariate analysis, older age (p = 0.039) and higher, still within the normal range, platelet count (p = 0.004) were independently associated with JAK2 V617F positivity in patients without overt MPN (Table 3). During a mean and median follow-up period of 59 (SD 46) and 49 (range 5–122) months, respectively, 2 JAK2 V617F-positive patients (28%) presented 4 new venous thromboembolic events (VTE; Table 2). One patient without overt MPN had a splanchnic thrombosis with Budd Chiari syndrome 47 months after the initial CVT (patient 1). Another patient without overt MPN had a second CVT associated with pulmonary embolism 20 months after the first CVT episode, and then a third episode of CVT 9 months after (patient 5). At the time of recurrence, patient 5 was treated with an oral anticoagulant with a satisfactory time in therapeutic INR range, in
Table 3. General, biological, and radiological data in CVT patients with and without JAK2 V617F mutation (without overt MPN) at univariate and multivariate analyses
Variable
JAK2 V617F mutation-positive patients (n = 7)
JAK2 V617F mutation-negative patients (n = 118)
Univariate p value
Multivariate p value
Age, years, mean (SD) Gender, female, n (%) Previous venous thromboembolism, n (%) RBC count, ×106/mm3, mean (SD) Hb, g/dL, mean (SD) Hematocrit, %, mean (SD) Platelets, ×103/mm3, mean (SD) WBC count, ×103/mm3, mean (SD) Fibrinogen, g/L, mean (SD) D-Dimers, ng/mL, mean (SD) CRP, mg/L, mean (SD) ESR, mm/h, mean (SD) Cerebral infarction/hemorrhage, n (%)
61 (17) 7 (100) 2 (28) 4.8 (1.2) 14.2 (2) 41.8 (5.5) 377 (88) 9 (2.8) 4.6 (1) 830 (975) 8.4 (14.3) 15 (13) 4 (57)
48 (19) 81 (69) 12 (10) 4.5 (0.6) 13.4 (2) 39.9 (5.4) 262 (107) 9.5 (3.8) 4.8 (1.9) 1,850 (1,861) 33.3 (66.4) 24 (25) 51 (43)
0.054 0.103 0.176 0.516 0.481 0.599 0.004 0.847 0.901 0.217 0.054 0.581 1
0.039
0.004
ied. About 30% of vascular events in Ph-negative MPN patients are VTE [27], which generally present as lower limb deep vein thrombosis or pulmonary artery embolism. However, in Ph-negative MPN, VTE characteristically occurs in uncommon locations such as splanchnic veins, including hepatic veins (presenting Budd-Chiari syndrome), portal and mesenteric veins, or, less frequently, cerebral veins or sinuses [15, 28]. In patients with MPN, the prevalence of CVT is 1% or less [23, 29, 30], and among patients with CVT, MPN is concomitantly diagnosed in 3–7% of cases [23, 31, 32]. Our study showed that the JAK2 V617F mutation is present in 7.1% of our CVT unselected patients and in 5.6% of CVT subjects without overt MPN. Only a few studies (Table 1) have investigated the relationship between JAK2 V617F mutation and CVT in the absence of distinct biological and/or clinical features of MPN [9, 19–22, 25, 32– 36]; the prevalence of the mutation has ranged from 0% [9, 19–21, 33, 34] to as much as 14% [22, 25, 35]. However, except for 2 studies including more than 100 subjects [22, 32], patient series have been relatively small. In a retrospective Italian study conducted on 152 CVT patients, JAK2 V617F mutation was detected in 10 of them (6.6%), and excluding those patients with an overt MPN, mutation prevalence was 2.7% (4 out of 146) [32]. In a large Indian series of 372 CVT patients without overt MPN, JAK2 V617F mutation was found in 5.9%, compared to 0.5% prevalence in controls, with a 5.47-fold increase in the risk
of CVT independently of other conventional vascular risk factors [22]. Considering these 12 studies together (including our study), with a total number of 1,019 patients with CVT and without overt MPN, the global prevalence of JAK2 V617F mutation is not negligible (3.9%). One of the other main findings of our study is that CVT subjects with JAK2 V617F were older and that though their platelet cell count was in the normal range, it was higher compared to patients without mutation, even in the absence of overt MPN. This finding was partially confirmed in a large Indian series, where patients with JAK2 V617F mutation, but without overt MPN, were also found to be older, with a higher mean hemoglobin level and with a trend toward a higher platelet count [22]. On the other hand, venous thrombosis at uncommon sites may also reveal an MPN, with overt biological and clinical signs, as was the case in 4 patients of our original series. In a series of 48 patients with MPN and CVT, diagnosis of MPN was concomitant to that of CVT in 46% of the patients, and 81% of JAK2 V617F positivity was observed [28]. In our opinion, this relatively high mutation prevalence may justify JAK2 V617F screening in all CVT patients, even in the absence of obvious signs of MPN [22, 25], and also in patients with other risk factors for CVT. Recently, the clinical characteristics of 48 patients with MPN and CVT were compared to those of 87 MPN patients with venous thromboses at other sites and 178
JAK2 V617F in CVT
Cerebrovasc Dis 2017;44:97–104 DOI: 10.1159/000471891
101
Downloaded by: Glasgow Univ.Lib. 130.209.6.61 - 9/6/2017 3:41:48 PM
RBC, red blood cells; Hb, hemoglobin; WBC, white blood cells; CRP, C-reactive protein; ESR, erythrocyte sedimentation rate.
102
Cerebrovasc Dis 2017;44:97–104 DOI: 10.1159/000471891
overt MPN are available. In our opinion, although the small sample size does not allow us to draw a definitive conclusion, the high risk of VTE recurrence in our JAK2 V617F subjects (28%) might suggest a definite oral anticoagulation in this specific subgroup of CVT patients. Cytoreductive treatment should probably be associated in the presence of even a slightly abnormal leukocyte, hematocrite, or platelet level. In patients with a first episode of CVT, the optimal duration of anticoagulant therapy has yet to be established. Short-term (3–12 months) anticoagulant therapy is generally accepted in patients with a transient risk factor at the time of the event; however, since MPN remains active, lifelong oral anticoagulant therapy should be considered, especially in patients with no removable risk factors at the time of thrombosis. A careful evaluation of individual hemorrhagic risk and a periodic follow-up of patients are advisable, since MPNs are progressive disorders and the general status of affected patients may change over time [42]. In conclusion, screening for the JAK2 V617F mutation in CVT patients might be useful even in the absence of overt MPN and/or in the presence of other risk factors for CVT because of its high prevalence, estimated to be 4%, and the high risk of thrombosis recurrence. The duration of anticoagulation is still under discussion [41]; however, when venous thrombosis occurs in patients with a persistent severe risk factor (e.g., severe thrombophilia), anticoagulant treatment is continued indefinitely [43]. Hence, although the optimal duration of anticoagulant therapy in patients with CVT who carry the JAK2 V617F mutation has yet to be established, we suggest caution in discontinuing anticoagulation, even if CVT has occurred in the presence of a transient risk factor. The choice of starting cytoreductive therapy should be determined on an individual basis [32].
Disclosure Statement The authors have no conflicts of interest to disclose.
References
1 Bousser MG, Ferro JM: Cerebral venous thrombosis: an update. Lancet Neurol 2007;6: 162–170. 2 Stam J: Thrombosis of the cerebral veins and sinuses. N Eng J Med 2005; 352: 1791– 1798. 3 Kralovics R, Passamonti F, Buser AS, Teo SS, Tiedt R, Passweg JR, Tichelli A, Cazzola M, Skoda RC: A gain-of-function mutation of JAK2 in myeloproliferative disorders. N Engl J Med 2005;352:1779–1790.
Lamy et al.
Downloaded by: Glasgow Univ.Lib. 130.209.6.61 - 9/6/2017 3:41:48 PM
MPN patients without thrombosis. A significantly higher prevalence of thrombophilia abnormalities (7% factor V Leiden, 5% prothrombin G202110A, and 24% hyperhomocysteinemia) was found in patients with MPN and CVT compared to patients with MPN but without thrombosis (40 vs. 21%), as well as a higher prevalence of JAK2 V617F mutation (78 vs. 55%) [28]. Furthermore, in our study, there were no specific clinical or radiological features that enabled us to differentiate JAK2 V617F-negative from JAK2 V617F-positive CVT patients. Another argument for systematic screening of the JAK2 V617F mutation in CVT is the high risk of VTE recurrence. In fact, because of the low number of outcome events, we were not able to draw definitive conclusions; in our study, 2 out of 7 CVT patients with JAK2 V617F positivity had single or multiple new venous thrombotic events at cerebral or extra-cerebral sites. Similarly, Martinelli et al. [28] observed that in the presence of overt MPN, CVT patients showed a higher rate of recurrent thrombosis, compared with patients with MPN and extracerebral venous thromboses (42 vs. 25%). Recurrence was essentially venous (80%) consisting of deep venous thrombosis (33%), pulmonary embolism (25%), splanchnic venous thrombosis (30%), and CVT (5%) [28]. Furthermore, among these CVT patients who experienced VTE recurrences, 80% were on antithrombotic treatment (vitamin K antagonist [VKA] with or without antiplatelet agents, subcutaneous heparin), and CVT was the only predictive variable [28]. In our series, recurrences happened, while one out of the 2 patients was being treated with oral anticoagulant with a satisfactory time in therapeutic range in combination with interferon-alpha and a cytoreductive treatment (hydroxyurea). However, the benefit of VKA in decreasing the risk of recurrence subsequent to a venous thrombotic event in MPN patients is well established [37–39], while the benefit of cytoreductive treatment has been shown mainly in patients with an arterial thrombosis [37]. Still, as was the case in one of the 2 JAK2 V617F-positive patients in the present study, in a cohort of 48 MPN patients with CVT, oral anticoagulation failed to prevent recurrence, [28] and further research is needed to improve preventive treatment. This recurrence risk could be higher in the presence of an increased leukocyte count at the time of the first thrombosis in patients under the age of 60 years old, in patients over 60 years old [37, 40], in those with inherited thrombophilia [38], and in patients with a previous history of thromboembolism [41]. In addition, no data regarding secondary prevention strategies in JAK2 V617F-positive CVT patients without
JAK2 V617F in CVT
14
15
16
17
18
19
20
21
22
23
24
tients with portal vein thrombosis. Dig Dis Sci 2008;53:2778–2783. Goulding C, Uttenthal B, Foroni L, Duke V, Traore A, Kottaridis P, Hoffbrand AV, Patch D, McNamara C: The JAK2(V617F) tyrosine kinase mutation identifies clinically latent myeloproliferative disorders in patients presenting with hepatic or portal vein thrombosis. Int J Lab Hematol 2008;30:415–419. Kiladjian JJ, Cervantes F, Leebeek FW, Marzac C, Cassinat B, Chevret S, Cazals-Hatem D, Plessier A, Garcia-Pagan JC, Darwish Murad S, Raffa S, Janssen HL, Gardin C, Cereja S, Tonetti C, Giraudier S, Condat B, Casadevall N, Fenaux P, Valla DC: The impact of JAK2 and MPL mutations on diagnosis and prognosis of splanchnic vein thrombosis: a report on 241 cases. Blood 2008;111:4922–4929. Xavier SG, Gadelha T, Pimenta G, Eugenio AM, Ribeiro DD, Gomes FM, Bonamino M, Zalcberg IR, Spector N: JAK2V617F mutation in patients with splanchnic vein thrombosis. Dig Dis Sci 2010;55:1770–1777. Dentali F, Squizzato A, Brivio L, Appio L, Campiotti L, Crowther M, Grandi AM, Ageno W: JAK2V617F mutation for the early diagnosis of Ph- myeloproliferative neoplasms in patients with venous thromboembolism: a meta-analysis. Blood 2009;113:5617–5623. Xavier SG, Gadelha T, Rezende SM, Zalcberg IR, Spector N: JAK2V617F mutation in patients with thrombosis: to screen or not to screen. Int Jnl Lab Hem 2011;33:117–124. Rossi D, Cresta S, Destro T, Vendramin C, Bocchetta S, De Paoli L, Cerri M, Lunghi M, Gaidano G: JAK2V617F in idiopathic venous thromboembolism occurring in the absence of inherited or acquired thrombophilia. Br J Haematol 2007;138:813–814. Bellucci S, Cassinat B, Bonnin N, Marzac C, Crassard I: The V617F JAK 2 mutation is not a frequent event in patients with cerebral venous thrombosis without overt chronic myeloproliferative disorder. Thromb Haemost 2008;99:1119–1120. Xavier SG, Gadelha T, Schaffel R, Britto L, Pimenta G, Ribeiro DD, Sabino Ade P, Pires V, Renault IZ, Spector N: Low prevalence of the JAK2V617F in patients with ischemic stroke or cerebral venous thrombosis. Blood Coagul Fibrinolysis 2008;19:468–469. De T, Prabhakar P, Nagaraja D, Christopher R: Janus kinase (JAK) 2 V617F mutation in Asian Indians with cerebral venous thrombosis and without overt myeloproliferative disorders. J Neurol Sci 2012;323:178–182. Dentali F, Ageno W, Rumi E, Casetti I, Poli D, Scoditti U, Maffioli M, di Minno MN, Caramazza D, Pietra D, De Stefano V, Passamonti F: Cerebral venous thrombosis and myeloproliferative neoplasms: results from two large databases. Thromb Research 2014; 134: 41–43. Janssen HL, Leebeek FW: JAK2 mutation: the best diagnostic tool for myeloproliferative disease in splanchnic vein thrombosis? Hepatology 2006;44:1391–1393.
25 De Stefano V, Rossi E, Za T, Chiusolo P, Leone G: The JAK2 V617F mutation in patients with cerebral venous thrombosis: a rebuttal. Thromb Haemost 2008;99:1121. 26 Tefferi A, Vardiman JW: Classification and diagnosis of myeloproliferative neoplasm: the 2008 WHO criteria. Leukemia 2008; 22: 14– 22. 27 Papadakis E, Hoffman R, Brenner B: Thrombohemorrhagic complications of myeloproliferative disorders. Blood Rev 2010; 24: 227– 232. 28 Martinelli I, De Stefano V, Carobbio A, Randi ML, Santarossa C, Rambaldi A, Finazzi MC, Cervantes F, Arellano-Rodrigo E, Rupoli S, Canafoglia L, Tieghi A, Facchini L, Betti S, Vannucchi AM, Pieri L, Cacciola R, Cacciola E, Cortelezzi A, Iurlo A, Pogliani EM, Elli EM, Spadea A, Barbui T: Cerebral vein thrombosis in patients with Philadelphia-negative myeloproliferative neoplasms. An European leukemia net study. Am J Hematol 2014; 89:E200– E205. 29 Bazzan M, Tamponi G, Schinco P, Vaccarino A, Foli C, Gallone G, Pileri A: Thrombosisfree survival and life expectancy in 187 consecutive patients with essential thrombocythemia. Ann Hematol 1999;78:539–543. 30 De Stefano V, Rossi E, Za T, Ciminello A, Betti S, Luzzi C, Leone G, Chiusolo P: JAK2 V617F mutational frequency in essential thrombocythemia associated with splanchnic or cerebral vein thrombosis. Am J Hematol 2011;86:526–528. 31 Ferro JM, Canhao P, Stam J, Bousser MG, Barinagarrementeria F; ISCVT Investigators: Prognosis of cerebral vein and dural sinus thrombosis: results of the international study on cerebral vein and dural sinus thrombosis (ISCVT). Stroke 2004;35:664–670. 32 Passamonti SM, Biguzzi E, Cazzola M, Franchi F, Gianniello F, Bucciarelli P, Pietra D, Mannucci PM, Martinelli I: The JAK2 V617F mutation in patients with cerebral venous thrombosis. J Thromb Haemost 2012;10:998– 1003. 33 Remacha AF, Estivill C, Sarda MP, Mateo J, Souto JC, Canals C, Nomdedéu J, Fontcuberta J: The V617F mutation of JAK2 is very uncommon in patients with thrombosis. Haematologica 2007;92:285–286. 34 Koopman K, Mulder AB, De Keyser J, Luijckx GJ, van der Meer J: JAK2-V617F mutation in cerebral venous thrombosis. J Thromb Haemost 2009;7:1039–1040. 35 Pardanani A, Lasho TL, Hussein K, Schwager SM, Finke CM, Pruthi RK, Tefferi A: JAK2V617F mutation screening as part of the hypercoagulable work-up in the absence of splanchnic venous thrombosis or overt myeloproliferative neoplasm: assessment of value in a series of 664 consecutive patients. Mayo Clin Proc 2008;83:457–459. 36 Shetty S, Kulkarni B, Pai N, Mukundan P, Kasatkar P, Ghosh K: JAK2 mutations across a spectrum of venous thrombosis cases. Am J Clin Pathol 2010;134:82–85.
Cerebrovasc Dis 2017;44:97–104 DOI: 10.1159/000471891
103
Downloaded by: Glasgow Univ.Lib. 130.209.6.61 - 9/6/2017 3:41:48 PM
4 Levine RL, Wadleigh M, Cools J, Ebert BL, Wernig G, Huntly BJ, Boggon TJ, Wlodarska I, Clark JJ, Moore S, Adelsperger J, Koo S, Lee JC, Gabriel S, Mercher T, D'Andrea A, Fröhling S, Döhner K, Marynen P, Vandenberghe P, Mesa RA, Tefferi A, Griffin JD, Eck MJ, Sellers WR, Meyerson M, Golub TR, Lee SJ, Gilliland DG: Activating mutation in the tyrosine kinase JAK2 in polycythemia vera, essential thrombocythemia, and myeloid metaplasia with myelofibrosis. Cancer Cell 2005;7: 387–397. 5 Tefferi A, Thiele J, Orazi A, Kvasnicka HM, Barbui T, Hanson CA, Barosi G, Verstovsek S, Birgegard G, Mesa R, Reilly JT, Gisslinger H, Vannucchi AM, Cervantes F, Finazzi G, Hoffman R, Gilliland DG, Bloomfield CD, Vardiman JW: Proposals and rationale for revision of the World Health Organization diagnostic criteria for polycythemia vera, essential thrombocythemia, and primary myelofibrosis: recommendations from an ad hoc international expert panel. Blood 2007; 110: 1092–1097. 6 Swerdlow SH, Campo E, Harris NL, Jaffe ES, Pileri SA, Stein H, Thiele J, Vardiman JW: WHO Classification of Tumours of Haematopoietic and Lymphoid Tissues. Lyon, IARC Press, 2008. 7 Patel RK, Lea NC, Heneghan MA, Westwood NB, Milojkovic D, Thanigaikumar M, Yallop D, Arya R, Pagliuca A, Gäken J, Wendon J, Heaton ND, Mufti GJ: Prevalence of the activating JAK2 tyrosine kinase mutation V617F in the Budd-Chiari syndrome. Gastroenterology 2006;130:2031–2038. 8 Primignani M, Barosi G, Bergamaschi G, Gianelli U, Fabris F, Reati R, Dell’Era A, Bucciarelli P, Mannucci PM: Role of the JAK2 mutation in the diagnosis of chronic myeloproliferative disorders in splanchnic vein thrombosis. Hepatology 2006;44:1528–1534. 9 Colaizzo D, Amitrano L, Iannaccone L, Vergura P, Cappucci F, Grandone E, Guardascione MA, Margaglione M: Gain-of-function gene mutations and venous thromboembolism: distinct roles in different clinical settings. J Med Genet 2007;44:412–416. 10 De Stefano V, Fiorini A, Rossi E, Za T, Farina G, Chiusolo P, Sica S, Leone G: Incidence of the JAK2 V617F mutation among patients with splanchnic or cerebral venous thrombosis and without overt chronic myeloproliferative disorders. J Thromb Haemost 2007; 5: 708–714. 11 McMahon C, Abu-Elmagd K, Bontempo FA, Kant JA, Swerdlow SH: JAK2 V617F mutation in patients with catastrophic intra-abdominal thromboses. Am J Clin Pathol 2007; 127:736–743. 12 Regina S, Herault O, D'Alteroche L, Binet C, Gruel Y: JAK2 V617F is specifically associated with idiopathic splanchnic vein thrombosis. J Thromb Haemost 2007;5:859–861. 13 Bayraktar Y, Harmanci O, Büyükasik Y, Shorbagi AI, Sungur AH, Boylu CA, Gürgey A, Balkanci F: JAK2V617F mutation in pa-
104
Sant'Antonio E, Vannucchi AM, Barbui T: High rate of recurrent venous thromboembolism in patients with myeloproliferative neoplasms and effect of prophylaxis with vitamin K antagonists. Leukemia 2016; 30: 2032–2038. 39 Barbui T, De Stefano V: Management of venous thromboembolism in myeloproliferative neoplasms. Curr Opin Hematol 2017;24: 108–114. 40 Marchioli R, Finazzi G, Landolfi R, Kutti J, Gisslinger H, Patrono C, Marilus R, Villegas A, Tognoni G, Barbui T: Vascular and neoplastic risk in a large cohort of patients with polycythemia vera. J Clin Oncol 2005; 23: 2224–2232. 41 Kreher S, Ochsenreither S, Trappe RU, Pabinger I, Bergmann F, Petrides PE, Koschmieder S, Matzdorff A, Tiede A, Griesshammer M,
Cerebrovasc Dis 2017;44:97–104 DOI: 10.1159/000471891
Riess H: Prophylaxis and management of venous thromboembolism in patients with myeloproliferative neoplasms: consensus statement of the Haemostasis Working Party of the German Society of Hematology and Oncology (DGHO), the Austrian Society of Hematology and Oncology (ÖGHO) and Society of Thrombosis and Haemostasis Research (GTH e.V.). Ann Hematol 2014; 93: 1953–1963. 42 Artoni A, Bucciarelli P, Martinelli I: Cerebral thrombosis and myeloproliferative neoplasms. Curr Neurol Neurosci Rep 2014; 14: 496. 43 Einhäupl K, Stam J, Bousser MG, De Bruijn SF, Ferro JM, Martinelli I, Masuhr F: EFNS guideline on the treatment of cerebral venous and sinus thrombosis in adult patients. Eur J Neurol 2010;17:1229–1235.
Lamy et al.
Downloaded by: Glasgow Univ.Lib. 130.209.6.61 - 9/6/2017 3:41:48 PM
37 De Stefano V, Za T, Rossi E, Vannucchi AM, Ruggeri M, Elli E, Micò C, Tieghi A, Cacciola RR, Santoro C, Gerli G, Vianelli N, Guglielmelli P, Pieri L, Scognamiglio F, Rodeghiero F, Pogliani EM, Finazzi G, Gugliotta L, Marchioli R, Leone G, Barbui T; GIMEMA CMDWorking Party: Recurrent thrombosis in patients with polycythemia vera and essential thrombocythemia: incidence, risk factors, and effect of treatments. Haematologica 2008; 93:372–380. 38 De Stefano V, Ruggeri M, Cervantes F, Alvarez-Larrán A, Iurlo A, Randi ML, Elli E, Finazzi MC, Finazzi G, Zetterberg E, Vianelli N, Gaidano G, Rossi E, Betti S, Nichele I, Cattaneo D, Palova M, Ellis MH, Cacciola R, Tieghi A, Hernandez-Boluda JC, Pungolino E, Specchia G, Rapezzi D, Forcina A, Musolino C, Carobbio A, Griesshammer M,
Received: November 23, 2016 Accepted: March 20, 2017 Published online: June 14, 2017
Should We Screen for Janus Kinase 2 V617F Mutation in Cerebral Venous Thrombosis? Matthias Lamy b Paola Palazzo a, b Pierre Agius b Jean Claude Chomel c Jonathan Ciron b Aline Berthomet b Paul Cantagrel b Julia Prigent b Pierre Ingrand d Mathieu Puyade e Jean-Philippe Neau b a
Department of Neurology, S. Giovanni Calibita-Fatebenefratelli Hospital, Rome, Italy; b Department of Neurology, Laboratory of Cancer Biology, d Clinical Investigation Center INSERM, and e Department of Oncology-Hematology and Cell Therapy, Poitiers University Hospital, Poitiers, France c
Abstract 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 longterm 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 V617Fpositive patients were followed up to detect new venous
© 2017 S. Karger AG, Basel E-Mail [email protected] www.karger.com/ced
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 followup 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. © 2017 S. Karger AG, Basel
Introduction
Cerebral venous thrombosis (CVT) is a rare and lifethreatening disease that affects about 3–5 people per million and accounts for 0.5% of all strokes [1, 2]. The etiology of CVT is multifactorial, involving genetic and acquired factors. Diverse conditions have been recognized
P.P. and M.L. equally contributed to the study.
Paola Palazzo Department of Neurology, Poitiers University Hospital 2 rue de la Milétrie FR–86021 Poitiers Cedex (France) E-Mail ppalazzo @ hotmail.it paola.palazzo @ chu-poitiers.fr
Downloaded by: Glasgow Univ.Lib. 130.209.6.61 - 9/6/2017 3:41:48 PM
Keywords Cerebral venous thrombosis · Anticoagulation · Coagulation abnormalities in cerebrovascular diseases · Hematology
Table 1. Prevalence of JAK2 V617F mutation in patients with cerebral venous thrombosis without overt myeloproliferative disorders Authors
Year of publication
Country
Setting
Subjects, n JAK2 V617F-positive subjects, n (%)
Colaizzo et al. [9]
2007
Italy
Thrombosis center
Remacha et al. [33]
2007
Spain
Department of hematology
2007
Italy
De Stefano et al. [10, 25]
2007, 2008
Pardanani et al. [35]
45
0 (0)
6
0 (0)
Division of hematology
13
0 (0)
Italy
Institute of hematology
48
3 (6.3)
2008
US
Division of hematology
7
1 (14)
Bellucci et al. [20]
2008
France
Hematology and neurology services
87
1 (1.1)
Xavier et al. [21]‡
2008
Brazil
Hematology service
44
0 (0)
Koopman et al. [34]§
2009
Netherlands Department of neurology and department of hematology
56
0 (0)
2010
India
Institute of immunohematology
70
2 (3)
Passamonti et al. [32]
2012
Italy
Hematology center
146
4 (2.7)
De et al. [22]**
2012
India
Department of neurochemistry and neurology
372
22 (5.9)
France
Department of neurology
125
7 (5.6)
Rossi et al. [19]* †
Shetty et al. [36]| | #
††
Present study All patients
1,019
40 (3.9 95% CI 2.8–5.3)
* This study did not include patients with inherited or acquired thrombophilia or subjects with risk factors for thrombosis including malignancy, surgery, pregnancy, oestrogen consumption, liver failure, and nephrotic syndrome. † The study consisted of 52 CVT patients, including 4 CVT patients with overt MPN, of whom 3 had the JAK2 V617F mutation. The study did not include CVT patients with malignancy. ‡ None of the patients with CVT had infections, trauma, malignancies, or autoimmune diseases. § The series consisted of 59 CVT patients, including 3 CVT patients with overt MPN, of whom 2 had the JAK2 V617F mutation. | | This study did not include patients with overt cancer or liver cirrhosis. # The study consisted of 152 CVT patients, including 6 CVT patients with overt MPN, all with the JAK2 V617F mutation. ** The study did not include patients with CVT secondary to head trauma, invasive procedures, sepsis, neuroinfection, or malignancy. †† The study did not include patients with CVT secondary to head trauma, invasive procedures, or associated with cerebral vascular malformations.
98
Cerebrovasc Dis 2017;44:97–104 DOI: 10.1159/000471891
from 12 to 74% [7–16] with a mean prevalence of 32.7% [17]. This wide range of JAK2 mutation positivity could be explained by several factors, including heterogeneity in the inclusion criteria, small sample size, different sensitivities of the assays employed for the detection of the mutation, and the different types of biological samples used [18]. However, only a few studies have evaluated the prevalence of the JAK2 V617F mutation in patients with CVT, and they have demonstrated distinctly lower prevalence, ranging from 0 to 14% (Table 1) [9, 10, 19–23]. Therefore, the actual diagnostic value of JAK2 V617F assessment as part of the routine thrombophilia investigation in patients with CVT still needs to be addressed [18, 24, 25]. Hence, the purpose of this prospective study was to evaluate the prevalence of JAK2 V617F mutation in a large group of consecutive CVT patients without known mutation status and to subsequently assess this prevalence in a subgroup of CVT patients without hematologLamy et al.
Downloaded by: Glasgow Univ.Lib. 130.209.6.61 - 9/6/2017 3:41:48 PM
as risk factors for this disease; oral contraceptive intake and puerperium are associated with an increased risk for CVT in younger women, while infectious and chronic inflammatory diseases, cancer, and myeloproliferative neoplasms (MPN) as well as trauma are acquired predisposing conditions in men and women at any age. The Janus Kinase 2 (JAK2) V617F (c.1849G>T, p.Val617Phe, according to the Human Genome Variation Society) somatic gain-of-function mutation has been found to be associated with polycythemia vera, essential thrombocythemia, and primary myelofibrosis [3, 4]. Its presence is now considered to be a major diagnostic criterion for MPN [5, 6]. Venous thrombotic complications (splanchnic, cerebral, or deep vein thromboses) are an important concern in MPN patients and may reveal the disease. Several studies have focused on the prevalence of JAK2 V617F mutation in patients with venous thrombosis. In patients with splanchnic vein thrombosis and without overt MPN, JAK2 V617F positivity has ranged
Methods
ing to the manufacturer’s instructions. The G1849T transversion (corresponding to the V617F mutation) was detected either by multiplex ARMS (amplification refractory mutation system) PCR (period August 2005 to June 2012) or by real-time PCR (from July 2012). The multiplex ARMS PCR method was performed in a 2-tube format; tube 1 contained the wild-type forward primer (5′-AGCA TTTGGTTTTAAATTATGGAGTATGGG-3′, 800 nM) and tube 2 the mutation forward primer (5′-AGCATTTGGTTTTAAATTATGGAGTATGCT-3′, 800 nM). Both tubes also contained the outer forward primer (5′-TGCTGAAAGTAGGAGAAAGTGC-3′, 40 nM) and the common reverse primer (5′-ACTTCATTGCTTTCCTTTTTCAC-3′, 400 nM). Amplifications were carried out in 50 μL with 10 mM Tris-HCl (pH 8.3), 50 mM KCl, 2.5 mM MgCl2, 200 μM each deoxynucleotide triphosphate, and 2.5 units of AmpliTaqGoldDNA Polymerase (Life Technologies, Carlsbad, CA, USA). The PCR conditions consisted of a denaturation at 95 ° C for 5 min, followed by 35 cycles of denaturation at 94 ° C for 30 s, annealing at 60 ° C for 60 s, and extension at 72 ° C for 50 s. Based on serial dilution experiments, the sensitivity of the method was set at 5%. The JAK2 V617F mutation was later detected using a real-time PCR method. JAK2 wild type and V617F alleles were specifically amplified using the JAK2 MutaSearch Kit (Ipsogen, Marseille, France) according to the manufacturer’s protocol. This kit has a sensitivity of 1% (mutated alleles among total JAK2 alleles).
Study Population The study group comprised of consecutive patients with a firstever CVT who were hospitalized between January 2005 and December 2014 in the department of Neurology of our academic hospital. CVT diagnosis was confirmed by one of the following methods: brain CT-scan with CT venography, MRI with MR venography, or conventional angiography (for a few patients). Neuroimaging was analyzed using a blind-test method by 2 of us (J.-P.N. and M.L.) to confirm the diagnosis of CVT. Exclusion criteria were (i) inconclusive neuroimaging studies; (ii) CVT secondary to head trauma, invasive procedures, or associated with cerebral vascular malformations; (iii) previously known MPN and/or presence of JAK2 V617F mutation. Baseline demographic, clinical, and radiological data were recorded, including vascular risk factors and family history of vascular events, location of thrombosis, and clinical presentation. Women were considered to be on oral contraceptives if they had taken them up until a week before the thrombotic event. Puerperal CVT was diagnosed when CVT occurred during the first 4 weeks after childbirth. All subjects underwent a detailed neurological examination and complete hematologic and biochemical exams. Thrombophilia testing included DNA analysis for factor V Leiden and G20210A prothrombin mutations; functional assays and/or immunoassays for plasma antithrombin, protein C and protein S; and antiphospholipid antibodies (lupus anticoagulant, anticardiolipin, and anti-b2 glycoprotein I antibodies). JAK2 V617F mutation analysis was assessed in all the study subjects. In the presence of clinical and biological features suggestive of MPN, hematological evaluation was conducted to confirm the diagnosis according to international guidelines [26]. This study was approved by the local Ethics Committee and informed written consent was obtained from all patients. JAK2 V617F-positive patients were followed up on an annual basis by means of a neurological outpatient visit. If an in-person evaluation was not possible, alternative methods included a telephone interview of the patient or an interview with a relative or their general practitioner. Detection of the JAK2 V617F Mutation in Blood Samples Genomic DNA was extracted from peripheral whole blood samples using a BioSprint 15 workstation (Qiagen, Hilden, Germany) and the BioSprint 15 DNA blood kit (Qiagen), accord-
JAK2 V617F in CVT
Statistical Analysis The prevalence of JAK2 V617F mutation was estimated by an exact binomial 95% CI, and compared with a pooled estimate from literature using Fisher’s exact test. Univariate analysis compared patients with and without JAK2 V617F mutation using the nonparametric Mann-Whitney test for quantitative variables and Fisher’s exact test for qualitative variables. Variables with a univariate p value below 0.20 were retained to be entered into a multivariate logistic regression analysis. The final logistic model was obtained after performing a backward elimination procedure. All tests were considered significant at the 5% level. Analyses were performed with SAS 9.4 (Cary NC, USA).
Results
One hundred and forty patients with a first event of radiologically confirmed CVT fulfilling the previously mentioned criteria were hospitalized in our department from January 2005 to December 2014. Fifteen of them were excluded for informed consent refusal (n = 5), death in the acute phase before JAK2 mutation assessment (n = 7), a previously known JAK2 V617F mutation (n = 1), or an overt MPN, which was detected during the CVT diagnostic workup (n = 2). Of the 125 subjects included, 7 were found to have JAK2 V617F mutation (5.6%; 95% CI 2.3–11.2), while 118 were JAK2 V617F mutation-negative (Fig. 1). Characteristics of JAK2-positive patients are detailed in Table 2, while general, biological, and radiological data Cerebrovasc Dis 2017;44:97–104 DOI: 10.1159/000471891
99
Downloaded by: Glasgow Univ.Lib. 130.209.6.61 - 9/6/2017 3:41:48 PM
ical abnormalities suggestive of overt MPN. The second objective was to compare clinical, biological, and radiological features in 2 groups of patients with CVT (JAK2 V617F-positive without overt MPN and JAK2 V617Fnegative) in order to detect a subgroup at higher risk for JAK2 V617F mutation, which would specifically benefit from mutation assessment. The third objective was to determine the long-term prognosis of CVT patients with JAK2 mutation but without overt MPN concerning venous thrombosis recurrences in view of recommending the best preventive treatment.
Table 2. Patients with CVT and JAK2 V617F mutation ID No. Gender
Age at Risk factors at Hb, Ht, % Platelets, WBC, CVT, years the time of CVT g/dL ×103 mm3 ×mm3
Follow-up, VKA treatment months duration, months
Cytoreductive treatment
Venous thrombotic recurrence
Delay, months
1 2 3 4 5 6 7
30 72 49 76 62 60 77
122 5 93 25 110 7 97
Hydroxyurea Hydroxyurea Hydroxyurea, anagrelide Phlebotomy Hydroxyurea Hydroxyurea None
ST – – – 2 Recurrent CVT/PE – –
47
F F F F F F F
OC – – – – – DVT, ST
14.0 14.7 13.3 14.0 11.4 12.6 9.6
42.1 42.3 39.6 43.0 36.3 36.1 33.5
334 371 345 196 345 436 423
5,600 8,500 8,300 9,900 5,600 7,600 7,000
115 5 92 25 110 6 85
20*
CVT, cerebral venous thrombosis; OC, oral contraceptive; WBC, white blood cell; VKA, vitamin K antagonist; PE, pulmonary embolism; DVT, deep venous thrombosis; ST, splanchnic thrombosis. * Delay from the first CVT episode to the first new venous thrombotic recurrence.
140 CVT patients 7 died 5 refused consent 1 had known JAK2 mutation status 127 patients 2 had overt MPN 125 patients
7 JAK2 V617F-positive patients
118 JAK2 V617F-negative patients
Fig. 1. Flowchart of the study population.
100
Cerebrovasc Dis 2017;44:97–104 DOI: 10.1159/000471891
combination with interferon-alpha and a cytoreductive treatment (hydroxyurea) with the goal of complete hematological remission. When considering all studies, including the present one, which have evaluated JAK2 V617F prevalence in a total number of 1,019 CVT patients without an overt MPN, the overall prevalence was found to be 3.9% (95% CI 2.8–5.3). Similarly, taking into account the 11 previous studies, global prevalence was 3.7% (95% CI 2.5–5.2), which was slightly, though not significantly lower than the percentage of our study prevalence (p = 0.32).
Discussion
Since the time acquired V617F mutation in the JAK2 gene was identified as a common event of Philadelphia (Ph)-negative MPN, its association with an increased arterial and venous thrombotic risk has been widely studLamy et al.
Downloaded by: Glasgow Univ.Lib. 130.209.6.61 - 9/6/2017 3:41:48 PM
in patients with JAK2 V617F mutation (without overt MPN) and without JAK2 V617F mutation in univariate analysis are shown in Table 3. In multivariate analysis, older age (p = 0.039) and higher, still within the normal range, platelet count (p = 0.004) were independently associated with JAK2 V617F positivity in patients without overt MPN (Table 3). During a mean and median follow-up period of 59 (SD 46) and 49 (range 5–122) months, respectively, 2 JAK2 V617F-positive patients (28%) presented 4 new venous thromboembolic events (VTE; Table 2). One patient without overt MPN had a splanchnic thrombosis with Budd Chiari syndrome 47 months after the initial CVT (patient 1). Another patient without overt MPN had a second CVT associated with pulmonary embolism 20 months after the first CVT episode, and then a third episode of CVT 9 months after (patient 5). At the time of recurrence, patient 5 was treated with an oral anticoagulant with a satisfactory time in therapeutic INR range, in
Table 3. General, biological, and radiological data in CVT patients with and without JAK2 V617F mutation (without overt MPN) at univariate and multivariate analyses
Variable
JAK2 V617F mutation-positive patients (n = 7)
JAK2 V617F mutation-negative patients (n = 118)
Univariate p value
Multivariate p value
Age, years, mean (SD) Gender, female, n (%) Previous venous thromboembolism, n (%) RBC count, ×106/mm3, mean (SD) Hb, g/dL, mean (SD) Hematocrit, %, mean (SD) Platelets, ×103/mm3, mean (SD) WBC count, ×103/mm3, mean (SD) Fibrinogen, g/L, mean (SD) D-Dimers, ng/mL, mean (SD) CRP, mg/L, mean (SD) ESR, mm/h, mean (SD) Cerebral infarction/hemorrhage, n (%)
61 (17) 7 (100) 2 (28) 4.8 (1.2) 14.2 (2) 41.8 (5.5) 377 (88) 9 (2.8) 4.6 (1) 830 (975) 8.4 (14.3) 15 (13) 4 (57)
48 (19) 81 (69) 12 (10) 4.5 (0.6) 13.4 (2) 39.9 (5.4) 262 (107) 9.5 (3.8) 4.8 (1.9) 1,850 (1,861) 33.3 (66.4) 24 (25) 51 (43)
0.054 0.103 0.176 0.516 0.481 0.599 0.004 0.847 0.901 0.217 0.054 0.581 1
0.039
0.004
ied. About 30% of vascular events in Ph-negative MPN patients are VTE [27], which generally present as lower limb deep vein thrombosis or pulmonary artery embolism. However, in Ph-negative MPN, VTE characteristically occurs in uncommon locations such as splanchnic veins, including hepatic veins (presenting Budd-Chiari syndrome), portal and mesenteric veins, or, less frequently, cerebral veins or sinuses [15, 28]. In patients with MPN, the prevalence of CVT is 1% or less [23, 29, 30], and among patients with CVT, MPN is concomitantly diagnosed in 3–7% of cases [23, 31, 32]. Our study showed that the JAK2 V617F mutation is present in 7.1% of our CVT unselected patients and in 5.6% of CVT subjects without overt MPN. Only a few studies (Table 1) have investigated the relationship between JAK2 V617F mutation and CVT in the absence of distinct biological and/or clinical features of MPN [9, 19–22, 25, 32– 36]; the prevalence of the mutation has ranged from 0% [9, 19–21, 33, 34] to as much as 14% [22, 25, 35]. However, except for 2 studies including more than 100 subjects [22, 32], patient series have been relatively small. In a retrospective Italian study conducted on 152 CVT patients, JAK2 V617F mutation was detected in 10 of them (6.6%), and excluding those patients with an overt MPN, mutation prevalence was 2.7% (4 out of 146) [32]. In a large Indian series of 372 CVT patients without overt MPN, JAK2 V617F mutation was found in 5.9%, compared to 0.5% prevalence in controls, with a 5.47-fold increase in the risk
of CVT independently of other conventional vascular risk factors [22]. Considering these 12 studies together (including our study), with a total number of 1,019 patients with CVT and without overt MPN, the global prevalence of JAK2 V617F mutation is not negligible (3.9%). One of the other main findings of our study is that CVT subjects with JAK2 V617F were older and that though their platelet cell count was in the normal range, it was higher compared to patients without mutation, even in the absence of overt MPN. This finding was partially confirmed in a large Indian series, where patients with JAK2 V617F mutation, but without overt MPN, were also found to be older, with a higher mean hemoglobin level and with a trend toward a higher platelet count [22]. On the other hand, venous thrombosis at uncommon sites may also reveal an MPN, with overt biological and clinical signs, as was the case in 4 patients of our original series. In a series of 48 patients with MPN and CVT, diagnosis of MPN was concomitant to that of CVT in 46% of the patients, and 81% of JAK2 V617F positivity was observed [28]. In our opinion, this relatively high mutation prevalence may justify JAK2 V617F screening in all CVT patients, even in the absence of obvious signs of MPN [22, 25], and also in patients with other risk factors for CVT. Recently, the clinical characteristics of 48 patients with MPN and CVT were compared to those of 87 MPN patients with venous thromboses at other sites and 178
JAK2 V617F in CVT
Cerebrovasc Dis 2017;44:97–104 DOI: 10.1159/000471891
101
Downloaded by: Glasgow Univ.Lib. 130.209.6.61 - 9/6/2017 3:41:48 PM
RBC, red blood cells; Hb, hemoglobin; WBC, white blood cells; CRP, C-reactive protein; ESR, erythrocyte sedimentation rate.
102
Cerebrovasc Dis 2017;44:97–104 DOI: 10.1159/000471891
overt MPN are available. In our opinion, although the small sample size does not allow us to draw a definitive conclusion, the high risk of VTE recurrence in our JAK2 V617F subjects (28%) might suggest a definite oral anticoagulation in this specific subgroup of CVT patients. Cytoreductive treatment should probably be associated in the presence of even a slightly abnormal leukocyte, hematocrite, or platelet level. In patients with a first episode of CVT, the optimal duration of anticoagulant therapy has yet to be established. Short-term (3–12 months) anticoagulant therapy is generally accepted in patients with a transient risk factor at the time of the event; however, since MPN remains active, lifelong oral anticoagulant therapy should be considered, especially in patients with no removable risk factors at the time of thrombosis. A careful evaluation of individual hemorrhagic risk and a periodic follow-up of patients are advisable, since MPNs are progressive disorders and the general status of affected patients may change over time [42]. In conclusion, screening for the JAK2 V617F mutation in CVT patients might be useful even in the absence of overt MPN and/or in the presence of other risk factors for CVT because of its high prevalence, estimated to be 4%, and the high risk of thrombosis recurrence. The duration of anticoagulation is still under discussion [41]; however, when venous thrombosis occurs in patients with a persistent severe risk factor (e.g., severe thrombophilia), anticoagulant treatment is continued indefinitely [43]. Hence, although the optimal duration of anticoagulant therapy in patients with CVT who carry the JAK2 V617F mutation has yet to be established, we suggest caution in discontinuing anticoagulation, even if CVT has occurred in the presence of a transient risk factor. The choice of starting cytoreductive therapy should be determined on an individual basis [32].
Disclosure Statement The authors have no conflicts of interest to disclose.
References
1 Bousser MG, Ferro JM: Cerebral venous thrombosis: an update. Lancet Neurol 2007;6: 162–170. 2 Stam J: Thrombosis of the cerebral veins and sinuses. N Eng J Med 2005; 352: 1791– 1798. 3 Kralovics R, Passamonti F, Buser AS, Teo SS, Tiedt R, Passweg JR, Tichelli A, Cazzola M, Skoda RC: A gain-of-function mutation of JAK2 in myeloproliferative disorders. N Engl J Med 2005;352:1779–1790.
Lamy et al.
Downloaded by: Glasgow Univ.Lib. 130.209.6.61 - 9/6/2017 3:41:48 PM
MPN patients without thrombosis. A significantly higher prevalence of thrombophilia abnormalities (7% factor V Leiden, 5% prothrombin G202110A, and 24% hyperhomocysteinemia) was found in patients with MPN and CVT compared to patients with MPN but without thrombosis (40 vs. 21%), as well as a higher prevalence of JAK2 V617F mutation (78 vs. 55%) [28]. Furthermore, in our study, there were no specific clinical or radiological features that enabled us to differentiate JAK2 V617F-negative from JAK2 V617F-positive CVT patients. Another argument for systematic screening of the JAK2 V617F mutation in CVT is the high risk of VTE recurrence. In fact, because of the low number of outcome events, we were not able to draw definitive conclusions; in our study, 2 out of 7 CVT patients with JAK2 V617F positivity had single or multiple new venous thrombotic events at cerebral or extra-cerebral sites. Similarly, Martinelli et al. [28] observed that in the presence of overt MPN, CVT patients showed a higher rate of recurrent thrombosis, compared with patients with MPN and extracerebral venous thromboses (42 vs. 25%). Recurrence was essentially venous (80%) consisting of deep venous thrombosis (33%), pulmonary embolism (25%), splanchnic venous thrombosis (30%), and CVT (5%) [28]. Furthermore, among these CVT patients who experienced VTE recurrences, 80% were on antithrombotic treatment (vitamin K antagonist [VKA] with or without antiplatelet agents, subcutaneous heparin), and CVT was the only predictive variable [28]. In our series, recurrences happened, while one out of the 2 patients was being treated with oral anticoagulant with a satisfactory time in therapeutic range in combination with interferon-alpha and a cytoreductive treatment (hydroxyurea). However, the benefit of VKA in decreasing the risk of recurrence subsequent to a venous thrombotic event in MPN patients is well established [37–39], while the benefit of cytoreductive treatment has been shown mainly in patients with an arterial thrombosis [37]. Still, as was the case in one of the 2 JAK2 V617F-positive patients in the present study, in a cohort of 48 MPN patients with CVT, oral anticoagulation failed to prevent recurrence, [28] and further research is needed to improve preventive treatment. This recurrence risk could be higher in the presence of an increased leukocyte count at the time of the first thrombosis in patients under the age of 60 years old, in patients over 60 years old [37, 40], in those with inherited thrombophilia [38], and in patients with a previous history of thromboembolism [41]. In addition, no data regarding secondary prevention strategies in JAK2 V617F-positive CVT patients without
JAK2 V617F in CVT
14
15
16
17
18
19
20
21
22
23
24
tients with portal vein thrombosis. Dig Dis Sci 2008;53:2778–2783. Goulding C, Uttenthal B, Foroni L, Duke V, Traore A, Kottaridis P, Hoffbrand AV, Patch D, McNamara C: The JAK2(V617F) tyrosine kinase mutation identifies clinically latent myeloproliferative disorders in patients presenting with hepatic or portal vein thrombosis. Int J Lab Hematol 2008;30:415–419. Kiladjian JJ, Cervantes F, Leebeek FW, Marzac C, Cassinat B, Chevret S, Cazals-Hatem D, Plessier A, Garcia-Pagan JC, Darwish Murad S, Raffa S, Janssen HL, Gardin C, Cereja S, Tonetti C, Giraudier S, Condat B, Casadevall N, Fenaux P, Valla DC: The impact of JAK2 and MPL mutations on diagnosis and prognosis of splanchnic vein thrombosis: a report on 241 cases. Blood 2008;111:4922–4929. Xavier SG, Gadelha T, Pimenta G, Eugenio AM, Ribeiro DD, Gomes FM, Bonamino M, Zalcberg IR, Spector N: JAK2V617F mutation in patients with splanchnic vein thrombosis. Dig Dis Sci 2010;55:1770–1777. Dentali F, Squizzato A, Brivio L, Appio L, Campiotti L, Crowther M, Grandi AM, Ageno W: JAK2V617F mutation for the early diagnosis of Ph- myeloproliferative neoplasms in patients with venous thromboembolism: a meta-analysis. Blood 2009;113:5617–5623. Xavier SG, Gadelha T, Rezende SM, Zalcberg IR, Spector N: JAK2V617F mutation in patients with thrombosis: to screen or not to screen. Int Jnl Lab Hem 2011;33:117–124. Rossi D, Cresta S, Destro T, Vendramin C, Bocchetta S, De Paoli L, Cerri M, Lunghi M, Gaidano G: JAK2V617F in idiopathic venous thromboembolism occurring in the absence of inherited or acquired thrombophilia. Br J Haematol 2007;138:813–814. Bellucci S, Cassinat B, Bonnin N, Marzac C, Crassard I: The V617F JAK 2 mutation is not a frequent event in patients with cerebral venous thrombosis without overt chronic myeloproliferative disorder. Thromb Haemost 2008;99:1119–1120. Xavier SG, Gadelha T, Schaffel R, Britto L, Pimenta G, Ribeiro DD, Sabino Ade P, Pires V, Renault IZ, Spector N: Low prevalence of the JAK2V617F in patients with ischemic stroke or cerebral venous thrombosis. Blood Coagul Fibrinolysis 2008;19:468–469. De T, Prabhakar P, Nagaraja D, Christopher R: Janus kinase (JAK) 2 V617F mutation in Asian Indians with cerebral venous thrombosis and without overt myeloproliferative disorders. J Neurol Sci 2012;323:178–182. Dentali F, Ageno W, Rumi E, Casetti I, Poli D, Scoditti U, Maffioli M, di Minno MN, Caramazza D, Pietra D, De Stefano V, Passamonti F: Cerebral venous thrombosis and myeloproliferative neoplasms: results from two large databases. Thromb Research 2014; 134: 41–43. Janssen HL, Leebeek FW: JAK2 mutation: the best diagnostic tool for myeloproliferative disease in splanchnic vein thrombosis? Hepatology 2006;44:1391–1393.
25 De Stefano V, Rossi E, Za T, Chiusolo P, Leone G: The JAK2 V617F mutation in patients with cerebral venous thrombosis: a rebuttal. Thromb Haemost 2008;99:1121. 26 Tefferi A, Vardiman JW: Classification and diagnosis of myeloproliferative neoplasm: the 2008 WHO criteria. Leukemia 2008; 22: 14– 22. 27 Papadakis E, Hoffman R, Brenner B: Thrombohemorrhagic complications of myeloproliferative disorders. Blood Rev 2010; 24: 227– 232. 28 Martinelli I, De Stefano V, Carobbio A, Randi ML, Santarossa C, Rambaldi A, Finazzi MC, Cervantes F, Arellano-Rodrigo E, Rupoli S, Canafoglia L, Tieghi A, Facchini L, Betti S, Vannucchi AM, Pieri L, Cacciola R, Cacciola E, Cortelezzi A, Iurlo A, Pogliani EM, Elli EM, Spadea A, Barbui T: Cerebral vein thrombosis in patients with Philadelphia-negative myeloproliferative neoplasms. An European leukemia net study. Am J Hematol 2014; 89:E200– E205. 29 Bazzan M, Tamponi G, Schinco P, Vaccarino A, Foli C, Gallone G, Pileri A: Thrombosisfree survival and life expectancy in 187 consecutive patients with essential thrombocythemia. Ann Hematol 1999;78:539–543. 30 De Stefano V, Rossi E, Za T, Ciminello A, Betti S, Luzzi C, Leone G, Chiusolo P: JAK2 V617F mutational frequency in essential thrombocythemia associated with splanchnic or cerebral vein thrombosis. Am J Hematol 2011;86:526–528. 31 Ferro JM, Canhao P, Stam J, Bousser MG, Barinagarrementeria F; ISCVT Investigators: Prognosis of cerebral vein and dural sinus thrombosis: results of the international study on cerebral vein and dural sinus thrombosis (ISCVT). Stroke 2004;35:664–670. 32 Passamonti SM, Biguzzi E, Cazzola M, Franchi F, Gianniello F, Bucciarelli P, Pietra D, Mannucci PM, Martinelli I: The JAK2 V617F mutation in patients with cerebral venous thrombosis. J Thromb Haemost 2012;10:998– 1003. 33 Remacha AF, Estivill C, Sarda MP, Mateo J, Souto JC, Canals C, Nomdedéu J, Fontcuberta J: The V617F mutation of JAK2 is very uncommon in patients with thrombosis. Haematologica 2007;92:285–286. 34 Koopman K, Mulder AB, De Keyser J, Luijckx GJ, van der Meer J: JAK2-V617F mutation in cerebral venous thrombosis. J Thromb Haemost 2009;7:1039–1040. 35 Pardanani A, Lasho TL, Hussein K, Schwager SM, Finke CM, Pruthi RK, Tefferi A: JAK2V617F mutation screening as part of the hypercoagulable work-up in the absence of splanchnic venous thrombosis or overt myeloproliferative neoplasm: assessment of value in a series of 664 consecutive patients. Mayo Clin Proc 2008;83:457–459. 36 Shetty S, Kulkarni B, Pai N, Mukundan P, Kasatkar P, Ghosh K: JAK2 mutations across a spectrum of venous thrombosis cases. Am J Clin Pathol 2010;134:82–85.
Cerebrovasc Dis 2017;44:97–104 DOI: 10.1159/000471891
103
Downloaded by: Glasgow Univ.Lib. 130.209.6.61 - 9/6/2017 3:41:48 PM
4 Levine RL, Wadleigh M, Cools J, Ebert BL, Wernig G, Huntly BJ, Boggon TJ, Wlodarska I, Clark JJ, Moore S, Adelsperger J, Koo S, Lee JC, Gabriel S, Mercher T, D'Andrea A, Fröhling S, Döhner K, Marynen P, Vandenberghe P, Mesa RA, Tefferi A, Griffin JD, Eck MJ, Sellers WR, Meyerson M, Golub TR, Lee SJ, Gilliland DG: Activating mutation in the tyrosine kinase JAK2 in polycythemia vera, essential thrombocythemia, and myeloid metaplasia with myelofibrosis. Cancer Cell 2005;7: 387–397. 5 Tefferi A, Thiele J, Orazi A, Kvasnicka HM, Barbui T, Hanson CA, Barosi G, Verstovsek S, Birgegard G, Mesa R, Reilly JT, Gisslinger H, Vannucchi AM, Cervantes F, Finazzi G, Hoffman R, Gilliland DG, Bloomfield CD, Vardiman JW: Proposals and rationale for revision of the World Health Organization diagnostic criteria for polycythemia vera, essential thrombocythemia, and primary myelofibrosis: recommendations from an ad hoc international expert panel. Blood 2007; 110: 1092–1097. 6 Swerdlow SH, Campo E, Harris NL, Jaffe ES, Pileri SA, Stein H, Thiele J, Vardiman JW: WHO Classification of Tumours of Haematopoietic and Lymphoid Tissues. Lyon, IARC Press, 2008. 7 Patel RK, Lea NC, Heneghan MA, Westwood NB, Milojkovic D, Thanigaikumar M, Yallop D, Arya R, Pagliuca A, Gäken J, Wendon J, Heaton ND, Mufti GJ: Prevalence of the activating JAK2 tyrosine kinase mutation V617F in the Budd-Chiari syndrome. Gastroenterology 2006;130:2031–2038. 8 Primignani M, Barosi G, Bergamaschi G, Gianelli U, Fabris F, Reati R, Dell’Era A, Bucciarelli P, Mannucci PM: Role of the JAK2 mutation in the diagnosis of chronic myeloproliferative disorders in splanchnic vein thrombosis. Hepatology 2006;44:1528–1534. 9 Colaizzo D, Amitrano L, Iannaccone L, Vergura P, Cappucci F, Grandone E, Guardascione MA, Margaglione M: Gain-of-function gene mutations and venous thromboembolism: distinct roles in different clinical settings. J Med Genet 2007;44:412–416. 10 De Stefano V, Fiorini A, Rossi E, Za T, Farina G, Chiusolo P, Sica S, Leone G: Incidence of the JAK2 V617F mutation among patients with splanchnic or cerebral venous thrombosis and without overt chronic myeloproliferative disorders. J Thromb Haemost 2007; 5: 708–714. 11 McMahon C, Abu-Elmagd K, Bontempo FA, Kant JA, Swerdlow SH: JAK2 V617F mutation in patients with catastrophic intra-abdominal thromboses. Am J Clin Pathol 2007; 127:736–743. 12 Regina S, Herault O, D'Alteroche L, Binet C, Gruel Y: JAK2 V617F is specifically associated with idiopathic splanchnic vein thrombosis. J Thromb Haemost 2007;5:859–861. 13 Bayraktar Y, Harmanci O, Büyükasik Y, Shorbagi AI, Sungur AH, Boylu CA, Gürgey A, Balkanci F: JAK2V617F mutation in pa-
104
Sant'Antonio E, Vannucchi AM, Barbui T: High rate of recurrent venous thromboembolism in patients with myeloproliferative neoplasms and effect of prophylaxis with vitamin K antagonists. Leukemia 2016; 30: 2032–2038. 39 Barbui T, De Stefano V: Management of venous thromboembolism in myeloproliferative neoplasms. Curr Opin Hematol 2017;24: 108–114. 40 Marchioli R, Finazzi G, Landolfi R, Kutti J, Gisslinger H, Patrono C, Marilus R, Villegas A, Tognoni G, Barbui T: Vascular and neoplastic risk in a large cohort of patients with polycythemia vera. J Clin Oncol 2005; 23: 2224–2232. 41 Kreher S, Ochsenreither S, Trappe RU, Pabinger I, Bergmann F, Petrides PE, Koschmieder S, Matzdorff A, Tiede A, Griesshammer M,
Cerebrovasc Dis 2017;44:97–104 DOI: 10.1159/000471891
Riess H: Prophylaxis and management of venous thromboembolism in patients with myeloproliferative neoplasms: consensus statement of the Haemostasis Working Party of the German Society of Hematology and Oncology (DGHO), the Austrian Society of Hematology and Oncology (ÖGHO) and Society of Thrombosis and Haemostasis Research (GTH e.V.). Ann Hematol 2014; 93: 1953–1963. 42 Artoni A, Bucciarelli P, Martinelli I: Cerebral thrombosis and myeloproliferative neoplasms. Curr Neurol Neurosci Rep 2014; 14: 496. 43 Einhäupl K, Stam J, Bousser MG, De Bruijn SF, Ferro JM, Martinelli I, Masuhr F: EFNS guideline on the treatment of cerebral venous and sinus thrombosis in adult patients. Eur J Neurol 2010;17:1229–1235.
Lamy et al.
Downloaded by: Glasgow Univ.Lib. 130.209.6.61 - 9/6/2017 3:41:48 PM
37 De Stefano V, Za T, Rossi E, Vannucchi AM, Ruggeri M, Elli E, Micò C, Tieghi A, Cacciola RR, Santoro C, Gerli G, Vianelli N, Guglielmelli P, Pieri L, Scognamiglio F, Rodeghiero F, Pogliani EM, Finazzi G, Gugliotta L, Marchioli R, Leone G, Barbui T; GIMEMA CMDWorking Party: Recurrent thrombosis in patients with polycythemia vera and essential thrombocythemia: incidence, risk factors, and effect of treatments. Haematologica 2008; 93:372–380. 38 De Stefano V, Ruggeri M, Cervantes F, Alvarez-Larrán A, Iurlo A, Randi ML, Elli E, Finazzi MC, Finazzi G, Zetterberg E, Vianelli N, Gaidano G, Rossi E, Betti S, Nichele I, Cattaneo D, Palova M, Ellis MH, Cacciola R, Tieghi A, Hernandez-Boluda JC, Pungolino E, Specchia G, Rapezzi D, Forcina A, Musolino C, Carobbio A, Griesshammer M,
