Incidence rates and risk factors for vascular events in patients with essential thrombocythemia: a multicenter study from Korea

Thrombotic and hemorrhagic events in 2016 World Health Organization-defined Philadelphia-negative myeloproliferative neoplasm

BACKGROUND/AIMS

Recent changes in the diagnostic criteria for myeloproliferative neoplasms (MPNs) and increasing patient numbers necessitate updating of the data on vascular events in patients with such disorders.

METHODS

In this single-center study, thrombotic and hemorrhagic events were retrospectively analyzed in patients diagnosed with essential thrombocythemia (ET), polycythemia vera (PV) prefibrotic/early primary myelofibrosis (pre-PMF), or PMF, based on the 2016 World Health Organization diagnostic criteria.

RESULTS

Of a total of 335 consecutive patients (139 ET, 42 pre-PMF, 124 PV, and 30 PMF patients; 192 males and 143 females) of median age 64 years (range, 15 to 91), 112 (33.4%) experienced a total of 126 thrombotic events before diagnosis, at the time of diagnosis, or during follow-up over a median of 4.6 years (range, 0.1 to 26.5). Cerebrovascular thrombosis (18.8%) was the most common initial event, followed by coronary heart disease (10.1%) and splanchnic (1.5%) and peripheral thrombosis (1.5%). Arterial thrombosis was more common than venous thrombosis (31.3% vs. 2.1%, respectively; p = 0.001). Thrombosis was most frequent in PV patients (39.5%), followed by patients with pre-PMF (38.1%), ET (30.9%), and PMF (13.3%). Of the 112 patients who experienced thromboses, 53 (47%) and 39 (33.9%) had thrombotic events before and at the time of MPN diagnosis, respectively. Twenty-seven patients (8.1%) experienced 29 hemorrhagic events, of which gastrointestinal bleeding (n = 20) was the most common.

CONCLUSION

Most thrombotic events occurred before or at the time of diagnosis, and the prevalence of arterial thrombosis was markedly higher than that of venous thrombosis in patients with MPN.

Combined venous and arterial thrombosis revealing underlying myeloproliferative disorder in a young patient: a case report

BACKGROUND

Myeloproliferative neoplasms (MPNs) such as polycythemia Vera (PV) and Essential Thrombocythemia (ET) can be associated with a high risk of both venous and arterial thrombosis. However, the co-existence between these two complications is very rare and has never been described before, especially in young adults with no known history of MPNs.

CASE PRESENTATION

We report the case of a 39 year-old Caucasian Moroccan male patient without cardiovascular risk factors (CVRF), who presented with acute chest pain. He also suffered from a severe headache since 2 weeks. Electrocardiogram (ECG) showed ST segment elevation myocardial infarction in the posterolateral leads. Cerebral Computed Tomography (CT) scan revealed subarachnoid hemorrhage (SAH), and cerebral Magnetic Resonance Angiography (MRA) found a Superior Sagittal Sinus Thrombosis (SSST). Routine blood tests showed raised hemoglobin and hematocrit in addition to leukocytosis and thrombocythemia. His coronary angiography revealed a thrombus in the ostial left circumflex artery (LCX). Further testing revealed positive Janus kinase 2 (JAK2) V617F mutation and low erythropoietin level, confirming the diagnosis of PV according to the 2008 World Health Organization (WHO) criteria. Antithrombotic and anti-ischemic treatments, in addition to myelosuppressive therapy with hydroxyurea, were initiated with a good clinical and biological evolution.

CONCLUSION

This case shows that MPNs are an important cause of thrombosis, especially in young patients with no other risk factors. Early diagnosis and appropriate management are fundamental before the occurrence of life-threatening complications that can sometimes present in unusual forms associating arterial and venous thrombotic events.

Ph- myeloproliferative neoplasms and the related risk factors for stroke occurrence: Results from a registry of patients treated with Anagrelide

Arterial thrombosis is a common complication in patients with Ph^- myeloproliferative neoplasms (MPN). We searched for the risk factors of stroke in MPN patients from anagrelide registry. We analyzed the potential risk factors triggering a stroke/TIA event in 249 MPN patients with previous stroke (n = 168) or Transient Ischemic Attack (TIA) (n = 140), and in 1,193 MPN control subjects (without clinical history of thrombosis). These patients were registered in a prospective manner, providing a follow-up period after Anagrelide treatment. The median age of the patients in the experimental group was of 56 years of age (ranging from 34-76) and of 53 years of age (ranging from 26-74) in the control group (p < 0.001). Using a multivariate model, we determined the following as risk factors: JAK2V617F mutation (OR 2.106, 1.458-3.043, p = 0.006), age (OR 1.017/year, 1.005-1,029, p = 0.006), male gender (OR 1.419, 1.057-1.903, p = 0.020), MPN diagnosis (OR for PMF 0.649, 0.446-0.944, p = 0.024), BMI (OR 0.687 for BMI > 25, 0.473-0.999, p = 0.05) and high TAG levels (OR 1.734, 1.162-2.586, p = 0.008), all of which were statistically significant for CMP development. Concerning the risk factors for thrombophilia, only the antiphospholipid syndrome (OR 1.994, 1.017-3.91, p = 0.048) was noteworthy in a stroke-relevant context. There was no significant difference between the blood count of the patients prior to a stroke event and the control group, both of which were under a cytoreductive treatment. We found that age, male gender, JAK2V617F mutation, previous venous thrombosis, and hypertriglyceridemia represent independent risk factors for the occurrence of a stroke in Ph^- MPN patients.

[Risk factors for recurrent thrombosis in patients with polycythemia vera and essential thrombocythemia]

Objective: To analyze the clinical characteristics of recurrent thrombosis in patients with polycythemia vera (PV) and essential thrombocythemia (ET) to probe the risk factors for recurrent thrombosis in patients with ET and PV. Methods: The clinical data of 104 ET and PV patients with thrombosis in Beijing Anzhen Hospital from February 2001 to November 2016 were retrospectively analyzed. Thrombosis reoccurred in 38 patients. Statistical analyses were performed by multivariate logistic regression for risk factors of recurrent thrombosis in ET and PV patients. Results: Recurrent thrombosis occurred in 36.5% of patients with ET/PV, the total incidence rate in ET and PV patients was 9.8% patient-years, 12.3% patient-years and 5.7% patient-years in ET and PV respectively. There were a total of 56 re-thrombotic events, and 42.1% of events occurred within 1 year after the first thrombosis. The arterial re-thrombosis was 97.4% (most of acute coronary syndrome, ACS), and venous events was 2.6%. The most common cases of re-thrombosis were ACS in ET patients (18 cases, 64.3%), and cerebral infarction in PV patients (7 cases, 70.0%). The number of PV patients with 2 times or more re-thrombotic events was significantly higher than that of ET patients (9 cases, 90.0% vs 7 cases, 25.0%). The proportion of the patients with WBC>12.5×10(9)/L or Hct>45%, and thrombosis history or splenomegaly and high risk thrombotic events were higher than those with a single thrombus (52.6% vs 31.8%; 50.0% vs 30.0%; 86.8% vs 13.6%; 84.2% vs 33.3%; 52.6% vs 15.2%; 94.7% vs 53.0%; P values were 0.036,0.046, <0.001, <0.001, <0.001 and <0.001, respectively). Logistic regression analysis showed that thrombosis history (OR=13.697, P=0.025), splenomegaly (OR=13.301, P=0.034) and high risk stratification of thrombotic events (OR=44.618, P=0.025) were independent risk factors for recurrent thrombotic events. Conclusions: ET and PV patients had a higher risk of re-thrombosis. The incidence of re-thrombosis in ET was higher than in PV, ACS was more common cases of re-thrombotic events; but PV patients were more susceptible to multiple re-thromboses than ET ones, also with more cerebral infarction. Previous thrombus history, splenomegaly and high risk stratification of thrombotic events were independent risk predictors for re-thrombosis of ET and PV patients.

Clinical significance of circulating microparticles in Ph- myeloproliferative neoplasms

Microparticles (MPs) are small membrane vesicles that are classified into subcategories based on their origin, such as platelet-derived MPs (PMPs), endothelial MPs (EMPs), red blood cell MPs (RMPs) and tissue factor MPs (TF + MPs). Philadelphia chromosome-negative myeloproliferative neoplasms (Ph^-MPN) are disorders characterized by abnormal haematopoiesis, thrombosis and the JAK2V617F mutation. MPs are biomarkers for procoagulant state in cancer patients, but their relevance in patients with Ph^-MPN was unclear. The present study aimed to measure MP variation in MPN patients and evaluate association with the JAK2V617F mutation and with thrombosis and splenomegaly. In total, 92 patients with MPN were enrolled in the present study, including 60 with essential thrombocythaemia (ET), 20 with polycythaemia vera (PV), and 12 with primary myelofibrosis (PMF). RMPs, PMPs, TF + MPs and EMPs were measured by flow cytometry. The levels of RMPs, PMPs, EMPs and TF + MPs in patients with Ph^-MPN were all found to be significantly increased compared with controls (P<0.05). Additionally, the levels of all four types of MPs in the PMF group were significantly increased compared with the PV group (P<0.05), and the level of RMPs in the PMF group was significantly increased compared with the ET group (P<0.05). MP levels were increased in the Ph^-MPN patients with thrombosis compared with patients without thrombosis (P<0.05). MP levels were increased in Ph^-MPN patients with splenomegaly compared with patients without splenomegaly (P<0.05). The level of PMPs in patients with the JAK2V617F mutation was increased compared with patients without the mutation (P<0.05). In conclusion, the present study showed that MPs are associated with Ph^-MPN pathogenesis, and may promote thrombosis.

Acute Coronary Syndromes in Patients with Hematological Disorders

Hematological conditions can lead to serious disturbances in blood rheology, being frequently associated with increased systemic inflammation and increased risk of bleeding. The imbalance between coagulation and thrombolytic factors in patients with acute coronary syndromes may lead to undesirable outcomes, and the success of emergency coronary angioplasty or by-pass grafting may be altered by increased bleeding in coagulopathies such as hemophilia. This paper intends to review the present knowledge in the field of acute coronary syndromes in subjects with hematological and onco-hematological disorders such as thrombotic thrombocytopenic purpura, immune thrombocytopenic purpura, von Willebrand disease, hemophilia, polycythemia vera, erythrocyte disorders, myelodysplastic syndrome, leukemia, lymphoma or myeloma.

Myocardial infarction as a thrombotic complication of essential thrombocythemia and polycythemia vera

OBJECTIVE

Detailed analyses of clinical characteristics of myocardial infarction (MI) as an essential thrombocythemia (ET)- and polycythemia vera (PV)-related complication have been so far presented mostly as case reports. Therefore, the aim of this retrospective analysis was to evaluate the main cardiological and hematological characteristics for better understanding myocardial complications in ET/PV.

METHODS

A retrospective analysis was carried out involving 263 patients diagnosed with ET or PV (155/108) between 1998 and 2014. Fourteen patients suffered MI during the hematological follow-up. Their clinical characteristics were compared to 162 patients (97 ET and 65 PV patients) who did not exhibit any major thrombotic complications (MI, stroke/transient ischemic attack, and venous events) before or after hematological diagnosis of ET/PV.

RESULTS

Fourteen MI events occurred among the 263 patients (5.3%). Vascular risk factors were found in 92.9% (13/14) of analyzed cases. In all, 71.4% of the MI complications developed within 12 months after the diagnosis of ET/PV. The coronary angiography findings revealed ST-elevation MI in four cases and non-ST-elevation MI in 10. Significant stenosis of coronary arteries requiring percutaneous coronary intervention with a stent implantation was present in seven cases, while three had complex stenoses or previous grafts/stents. All of them had undergone coronary artery bypass graft operations.

CONCLUSION

The results of the present study suggest that early detection and consideration of individual management of vascular risk factors in ET/PV patients are also important. Furthermore, a better theoretic understanding of platelet activation and role of leukocytes in myeloproliferative neoplasm-related thrombosis could open new perspectives in thrombosis prediction and prevention.

The impact of JAK2V617F mutation on different types of thrombosis risk in patients with essential thrombocythemia: a meta-analysis

To assess the effect of JAK2V617F on different thrombotic risks in essential thrombocythemia (ET) patients, we identified eligible studies from several databases including Pubmed, Embase, and Cochrane Central Register of Controlled Trials (up to November 2014). Twenty-two studies of 2922 ET patients were included in exploring the relationship between JAK2V617F and the risk of thrombosis. Compared to JAK2V617F-negative ET patients, JAK2V617F-positive ET patients had higher odd risks (ORs) of arterial thrombosis [OR = 2.59 (1.84-3.65)] and venous thrombosis [OR = 2.10 (1.53-2.88)]. The JAK2V617F-positive group was also more prone to increased risk of microcirculatory disturbances [OR = 1.50 (0.97-2.32)]. Moreover, JAK2V617F may indicate increased risk of either arterial [OR = 1.71 (1.22-2.39)] or venous thrombosis [OR = 2.90 (1.54-5.46)] before diagnosis of ET. During follow-up, JAK2V617F might not be related to arterial thrombosis [OR = 1.90 (0.90-2.08)], but rather venous thrombosis [OR = 1.95 (1.08-3.53)]. In conclusion, JAK2V617F increased the risk of arterial and venous thrombosis in ET patients, while understanding its role in microcirculatory disturbances will require further studies.

[Thrombotic events and significance of the IPSET thrombosis risk evaluation score in essential thrombocythaemia]

INTRODUCTION

Thrombo-haemorrhagic complications contribute to both morbidity and mortality in patients with essential thrombocythaemia.

AIM

The aim of the authors was to estimate the incidence of thrombotic events and to examine the clinical utility of IPSET thrombosis risk evaluation score against conventional two-categorical (low and high) risk assessment.

METHOD

A retrospective analysis was carried out on 155 patients with essential thrombocythaemia (106 females; median age, 61 years) in a period between 1999 and 2014.

RESULTS

The analysis revealed 55 (35.5%) major thrombotic events before and 25 (16.1%) major thrombotic complications after establishment of the haematologic diagnosis. Significant differences were observed in thrombosis-free survival between the different IPSET groups (p = 0.002).

CONCLUSIONS

The IPSET model was first examined in this cohort of patients with essential thrombocythaemia diagnosed in a single Hungarian haematologic centre. The results suggest that this score may provide more information than the conventional thrombosis risk assessment.

Association between thromboembolic events and the JAK2 V617F mutation in myeloproliferative neoplasms

Thrombotic complications are a major cause of death in patients with Philadelphia chromosome-negative myeloproliferative neoplasms (MPNs), which are closely associated with the JAK2 V617F activating mutation. However, whether the presence of the JAK2 V617F mutation affects thrombotic risk is currently unknown, although some reports have suggested a variable association with thrombosis. Therefore, we investigated the association between JAK2 V617F and various complications, including thrombosis, in Japanese patients with MPNs. We assessed the JAK2 V617F status in 140 patients who were diagnosed or doubted as having some type of MPN by utilizing a JAK2 V617F-specific guanine-quenching probe. JAK2 V617F was detected in 31 of 51 patients (60.8%) with essential thrombocythemia, all 16 patients (100%) with polycythemia vera, 4 of 11 patients (36.4%) with primary myelofibrosis, 2 of 18 patients (11.1%) with other types of MPNs, and none of the 44 patients with doubted MPN. In the 78 patients with classical MPN, JAK2 V617F correlated with a leukocyte count ≥10,000/μl (p=0.046). Complications of thrombosis, hemorrhage, and leukemic transformation occurred in 21 (41.2%), 4 (25.0%), and 3 (27.3%) patients with classical MPN, respectively, and thrombotic events (TE) occurred more frequently in patients with JAK2 V617F than without (p=0.047). Based on these findings, initial screening for the JAK2 mutation and careful monitoring for thrombotic events should be performed in patients with MPN.

Enterovirus 71 infection cleaves a negative regulator for viral internal ribosomal entry site-driven translation

Far-upstream element-binding protein 2 (FBP2) is an internal ribosomal entry site (IRES) trans-acting factor (ITAF) that negatively regulates enterovirus 71 (EV71) translation. This study shows that EV71 infection cleaved FBP2. Live EV71 and the EV71 replicon (but not UV-inactivated virus particles) induced FBP2 cleavage, suggesting that viral replication results in FBP2 cleavage. The results also showed that virus-induced proteasome, autophagy, and caspase activity co-contribute to EV71-induced FBP2 cleavage. Using FLAG-fused FBP2, we mapped the potential cleavage fragments of FBP2 in infected cells. We also found that FBP2 altered its function when its carboxyl terminus was cleaved. This study presents a mechanism for virus-induced cellular events to cleave a negative regulator for viral IRES-driven translation.

Thrombotic disease in the myeloproliferative neoplasms

Thrombosis is a leading cause of morbidity and mortality in patients with Philadelphia chromosome–negative myeloproliferative neoplasms (MPNs), particularly polycythemia vera and essential thrombocythemia. Mechanisms involved in the pathogenesis of the acquired thrombophilic state associated with these diseases include abnormalities of MPN clone–derived blood cells, which display prothrombotic features, and abnormalities of normal vascular cells, which become procoagulant in response to inflammatory stimuli. Ultimately, the release into the blood of elevated levels of procoagulant microparticles by platelets and vascular cells and the increase in the global thrombin generation due to an acquired activated protein C resistance result in a highly prothrombotic scenario in patients with polycythemia vera and essential thrombocythemia. The acquired point mutation in the pseudokinase domain of JAK2 (JAK2V617F) in these disorders is variably associated with thrombosis and, more consistently, with elevations in WBC counts and alterations in biomarkers of blood-clotting abnormalities. The predictive value of these biomarkers for thrombosis remains to be established to identify subsets of patients at elevated risk who may benefit from prophylaxis with antithrombotic drugs.