Cerebrovascular events as presenting manifestations of Myeloproliferative Neoplasm

Hematological causes of acute ischemic stroke in younger individuals

Ischemic stroke is a common cause of morbidity and mortality worldwide. The majority of affected individuals are older, with clear cardiovascular or embolic risk factors; however, up to a fifth of cases may occur in patients under the age of 50 years. In this review, we discuss some common hematological causes of ischemic stroke in this age range, with a focus on antiphospholipid syndrome, myeloproliferative neoplasms, immune thrombocytopenic purpura, and sickle cell disease. We review the etiology of stroke associated with these conditions and explore important management considerations that may be unique to these settings. These include the choice of antithrombotic agents, cytoreduction in myeloproliferative neoplasms, management of thrombocytopenia in immune thrombocytopenic purpura, and treatment of sickle cell disease.

JAK2 V617F Mutation and Large Cerebral Artery Disease in Patients with Myeloproliferative Neoplasms

AIM

The aim of the present study was to clarify the association between the Janus kinase 2 (JAK2) V617F mutation and large cerebral artery disease (LCAD) in patients with myeloproliferative neoplasms (MPNs).

METHODS

We retrospectively analysed patients diagnosed with MPNs between June 1992 and June 2022 who underwent brain magnetic resonance imaging. LCAD was defined as extracranial or intracranial large artery stenosis (≥ 50%) or occlusion on magnetic resonance angiography.

RESULTS

A total of 86 patients (47 males; median age, 69 years old) were enrolled in this study. JAK2 V617F mutation was detected in 63 (73.3%) patients and LCAD in 35 (40.7%) patients. Univariate analysis showed that history of ischaemic stroke (LCAD, 62.9% vs. non-LCAD, 11.8%; P＜0.001), JAK2 V617F mutation (91.4% vs. 60.8%, P=0.002), and age ≥ 60 years (85.7% vs. 60.8%, P=0.016) were significantly associated with LCAD. Multiple logistic regression analysis showed that, in addition to ischaemic stroke, age ≥ 60 years and diabetes mellitus, JAK2 V617F mutation (odds ratio 29.2, 95% confidence interval 1.2-709.8, P=0.038) was independently associated with LCAD. LCAD was frequently observed in the intracranial carotid (14/35, 40.0%) and middle cerebral (13/35, 37.1%) arteries.

CONCLUSIONS

This study revealed a significant association between the JAK2 V617F mutation and LCAD in patients with MPNs. This suggests that the JAK2 V617F mutation may promote cerebrovascular atherosclerosis and could be very important in determining therapeutic strategies for patients with not only JAK2 V617F-mutated MPNs but also LCAD-related stroke.

Association of polycythemia vera with non‑cirrhotic portal hypertension in five patients: A case series

Polycythemia vera (PV) and non-cirrhotic portal hypertension (NCPH) are relatively independent diseases, and few studies have linked them. However, in clinical settings, there may be a causal relationship. The aim of the present study was to analyze the clinical data of five patients with portal hypertension caused by PV and summarize the characteristics of PV with portal hypertension, to enhance the knowledge of this disease. The clinical data of five patients with PV and portal hypertension treated at Beijing You'an Hospital (Beijing, China) from January 2010 to March 2022 were retrospectively collected. The characteristics of these patients were then summarized and analyzed, including general information, laboratory tests, imaging and gastroscopy data. Overall, four patients were diagnosed with PV earlier compared with those with NCPH (ranging between days and years), whereas one patient was diagnosed with NCPH at the time of PV diagnosis. These four patients had blood cell elevations of 2-3 categories (red blood cells, white blood cells or platelets). The Child classification of liver functions in all five patients were found to be grades A-B. All five patients had splenomegaly, where three patients had portal vein thrombosis and cavernous degeneration. In addition, four patients had moderate or severe esophageal varices. In conclusion, to the best of our knowledge, this was the first case series of NCPH caused by PV. Among the patients, it was revealed that: i) NCPH caused by PV had milder liver function damage compared with cirrhosis-induced portal hypertension; ii) splenomegaly, ascites and esophageal varicose veins were prominent symptoms of NCPH caused by PV; iii) If PV is diagnosed, esophagogastroduodenoscopy should be performed as early as possible and regularly, where primary prevention measures for esophageal variceal hemorrhage are recommended; and iv) patients with PV with portal hypertension are at risk of thrombosis and bleeding, but it remains to be determined whether early antithrombotic therapy can reduce complications.

Prevalence and Therapeutic Implications of Clonal Hematopoiesis of Indeterminate Potential in Young Patients With Stroke

BACKGROUND

Undetermined stroke etiology hampers optimal secondary prevention in a large proportion of young patients. We explored whether genetic screening for clonal hematopoiesis of indetermined potential (CHIP), a novel risk factor for stroke, could identify patients with myeloid precursor lesions or covert myeloid neoplasm requiring specific treatment.

METHODS

We performed targeted sequencing on 56 genes recurrently mutated in hematologic neoplasms in a prospective cohort of patients with acute brain ischemia between 18 and 60 years. CHIP prevalence was compared with age-matched healthy controls from the Nijmegen Biomedical Study (n=1604) and the UK Biobank (n=101 678). Patients with suspicion of high-risk CHIP or myeloid neoplasm were invited for further hematologic evaluation.

RESULTS

We included 248 consecutive patients (39% women) of whom 176 (71%) had cryptogenic stroke etiology. Fifty-one (21%) patients had CHIP, 3-fold more than in the general population (7.7% versus 2.6% for the Nijmegen Biomedical Study and 11.9% versus 4.1% for UK Biobank; P<0.001 for both). Patients with CHIP were older (median [interquartile range], 53 [50-59] versus 51 [41-56] years; P<0.001), had higher carotid intima-media thickness (0.68 [0.58-0.80] versus 0.59 [0.51-0.73] mm; P=0.009), and had higher burden of atherosclerosis (29.4% versus 16.7%; P=0.04). We invited 11 patients (4.4%) for further hematologic assessment, which in 7 led to the diagnosis of high-risk CHIP and in 2 to the new diagnosis of a myeloproliferative neoplasm with indication for cytoreductive therapy.

CONCLUSIONS

Using genetic screening for myeloid disorders in patients with stroke of predominantly undetermined etiology, we found a 3-fold higher CHIP prevalence than in the general population. We identified high-risk CHIP and previously covert myeloproliferative neoplasms as potential stroke etiologies in 4.4% and 1% of patients, respectively. Our findings demonstrate the diagnostic and therapeutic yield of genetic screening in young patients with stroke. Future studies should investigate the role of CHIP for stroke recurrence and optimal secondary prevention.

A case of ischemic stroke with hemorrhagic transformation associated with essential thrombocythemia and JAK-2 V617F mutation

Background

Essential thrombocythemia (ET) is a rare cause of stroke. The V617F mutation in the Janus kinase 2 (JAK2) gene is one of the most typical mutations in ET and has been shown to be a risk factor for stroke, especially in younger people. However, to date, there have been few reports of intracranial thrombotic and hemorrhagic complications in patients with ET. Herein, we present a case of JAK2 gene mutation-associated ET in a patient who developed both ischemic and hemorrhagic stroke, and discuss potential underlying mechanisms.

Case presentation

A 45-year-old Chinese male presented to our center with gradually developing weakness of the right limbs for 3 months. A computed tomography scan of the brain showed an area of infarction with hemorrhage in the left subcortical and corona radiata regions. High-resolution magnetic resonance imaging revealed a thrombosis on the surface of the atherosclerotic plaque. Digital subtraction angiography revealed an insect bite-like change in the C1 branch of the left internal carotid artery, which caused up to 50% stenosis. Blood tests showed continued elevation of the platelet and white blood cell counts. After consultation with a hematologist, a bone marrow biopsy was performed, which revealed proliferative bone marrow changes with numerous megakaryocytes and proliferative but mature granulocytes. Further genetic testing revealed a positive JAK2-V617F mutation. Therefore, the diagnosis of ET was confirmed according to the World Health Organization (WHO) 2016 diagnostic criteria. Finally, we decided to administer aspirin and hydroxyurea. The patient remained stroke free and the platelet levels were normal throughout the 1-year follow-up period.

Conclusions

JAK2 mutations affect the proliferation and differentiation of blood cells through the JAK, signal transducer and activator of transcription pathway, which leads to changes in platelets and macrophages, and an increase in neutrophil extracellular traps, which may explain the patient’s ischemic and hemorrhagic changes. Further investigation of the underlying mechanisms may change the treatment strategy for such patients in the future.

Ischemic stroke as a presenting manifestation of polycythemia vera: a narrative review

Polycythemia vera (PV) is a myeloproliferative disorder associated with an increased risk of cerebrovascular diseases. In this narrative review, we aimed to analyze the relationships between acute ischemic stroke and PV. We conducted a PubMed/Medline and Web of Sciences Database search using MeSH major terms. We found 75 articles and finally considered 12 case reports and 11 cohort studies. The ischemic stroke resulted as the first manifestation of PV in up to 16.2% of cases; the cumulative rate of cerebrovascular events was up to 5.5 per 100 persons per year and stroke accounted for 8.8% of all PV-related deaths; age, mutations, and a previous history of thrombosis were the main risk factors. The best approach to reduce stroke recurrence risk is unclear, even if some evidence suggests a potential role of lowering hematocrit below 45%. Ischemic stroke represents one of the most common PV manifestations but, despite their relationship, patients with both diseases have a very heterogeneous clinical course and management. PV-related strokes often remain underdiagnosed, especially for the low prevalence of PV. An early diagnosis could lead to prompt treatment with phlebotomy, cytoreduction, and low-dose aspirin to decrease the risk of recurrences. Clinicians should be aware of PV as a risk factor for stroke when approaching the differential diagnosis of cryptogenic strokes. An early diagnosis could positively influence patients' management and clinical outcomes. Further studies are required to evaluate the role of PV treatments in the prevention of cerebrovascular disease.

JAK 2 positive myeloproliferative neoplasm presenting as stroke, recurrent TIA and isolated third nerve palsy

A man in his early 40s with no significant vascular risk factors was managed within a period of 6 months for recurrent vascular events: ischaemic stroke, transient ischaemic attack and isolated third nerve palsy. He was extensively investigated throughout the course of illness. The only potential aetiological factor identified was a positive janus kinase 2 (JAK 2) mutation after screening on account of mildly elevated platelet count noted during his most recent admission. Bone marrow aspiration confirmed essential thrombocythaemia. He was started on hydroxycarbamide and has remained relatively symptom free since then.This case reiterates the known associations between thrombosis and JAK 2 mutation even without overt myeloproliferative neoplasms. It also highlights the need for specialists in stroke to consider screening for JAK 2 mutation in a young patient with cryptogenic stroke with or without polycythemia or thrombocytosis.

Cerebrovascular manifestations in hematological diseases: an update

Patients with hematological diseases often experience cerebrovascular complications including ischemic stroke, intracerebral and subarachnoid hemorrhage, microbleeds, posterior reversible encephalopathy syndrome, and dural sinus and cerebral vein thrombosis (CVT). In this update, we will review recent advances in the management of cerebrovascular diseases in the context of myeloproliferative neoplasms, leukemias, lymphomas, multiple myeloma, POEMS, paroxysmal nocturnal hemoglobinuria (PNH), thrombotic thrombocytopenic purpura (TTP), and sickle-cell disease. In acute ischemic stroke associated with hematological diseases, thrombectomy can in general be applied if there is a large vessel occlusion. Intravenous thrombolysis can be used in myeloproliferative neoplasms and sickle-cell anemia, but in other diseases, a case-by-case evaluation of the bleeding risks is mandatory. Patients with sickle-cell disease and acute stroke need very often to be transfused. In PNH, acute ischemic stroke patients must be anticoagulated. Most patients with CVT can be treated with low-molecular weight heparin (LMWH) acutely, even those with leukemias. Prevention of recurrence of cerebral thrombotic events depends on the control of the underlying disease, combined in some conditions with antithrombotic drugs. The recent introduction of specific monoclonal antibodies in the treatment of PHN and TTP has dramatically reduced the risk of arterial and venous thrombosis.

Essential thrombocythemia - a predisponent factor for stroke

The essential thrombocythemia is one of the seven described forms of myeloproliferative neoplasms. It is characterized by megakaryocytic hyperplasia with consequent thrombocytosis maintained in the peripheral blood, favoring the occurrence of thrombo-hemorrhagic phenomena. We present the case of an 81-year-old woman with a history of ischemic stroke in the context of a sustained thrombocytosis, which led to a spinal study and a search for the V617F mutation in the JAK2 gene, which was positive. The patient started cytoreductive therapy with hydroxyurea with favorable current evolution.

Recurrent ischaemic cerebrovascular events as presenting manifestations of myeloproliferative neoplasms

BACKGROUND AND PURPOSE

Myeloproliferative neoplasms (MPNs) - polycythemia vera, essential thrombocythemia and primary myelofibrosis - are associated with increased risk for ischaemic cerebrovascular events (ICVEs). Due to their low prevalence, MPNs often remain undiagnosed as the cause of ICVEs.

METHODS

Case records at the University of Tübingen between 2014 and 2017 were screened to identify patients with MPN-related ICVEs. Clinical features, brain imaging, laboratory findings, applied treatments and neurological outcomes were assessed.

RESULTS

In all, 3318 patients with ICVEs were identified, and amongst them 17 patients with MPN-related ICVEs were included in a retrospective study. In 58% of these patients, ICVEs were the first manifestation of the underlying MPN; 24% presented with transient ischaemic attack and 76% with ischaemic stroke. Potentially concurrent ICVE etiologies were noted in 70% of the patients. The majority (94%) of patients were positive for the JAK2 V617F mutation, whilst in 29% recurrent ICVEs (range two to three) were noted prior to MPN diagnosis. Early MPN diagnosis and management was the only significant prognostic factor for ICVE recurrence (P < 0.001).

DISCUSSION

Evidence is provided that, although rare, MPNs represent an underdiagnosed cause of recurrent ICVEs. High clinical awareness is warranted to identify an underlying MPN in patients presenting with sustained, abnormal blood count findings. Clinical algorithms for prompt MPN diagnosis and initiation of MPN treatment (e.g. cytoreductive therapy, phlebotomy) are required. As MPN management comprises a significant protective factor against ICVE recurrence, induction of MPN treatment should be regarded as an integral component of secondary stroke prevention in MPN-associated ICVEs.

Implications of Janus Kinase 2 Mutation in Embolic Stroke of Unknown Source

The role of genetic mutations in cerebral ischemia is not completely understood. Among these genetic variations, Philadelphia-negative gain-of-function mutation in the janus kinase 2 (JAK2) protein leads to overexpression of the genes involved in cell growth and proliferation, and has been linked to development of hematological malignancies, specifically, myeloproliferative neoplasms (MPNs; essential thrombocythemia [ET], polycythemia vera [PV], and primary myelofibrosis). Overt ET and PV are known to induce a prothrombotic state that leads to development of vascular complications, including cerebral arterial or venous thrombosis. Thromboembolism can precede overt presentation of an MPN by 2-3 years. As such, for the selected cases of embolic stroke or cerebrovascular sinus thrombosis with otherwise undetermined source and persistent thrombocytosis or polycythemia, in the absence of a confirmed MPN diagnosis, screening for JAK2 mutation may be reasonable, as early diagnosis and appropriate treatment can influence outcome by preventing recurrent thrombotic events. In this article, we review the literature on the genetics, pathogenesis, clinical manifestations, and treatment of JAK2-associated thrombosis, and present 2 cases of JAK2-associated cerebral arterial infarction and cerebral and systemic venous thromboembolism with otherwise negative etiology workup for stroke.