Comparison between thrombotic risk scores in essential thrombocythemia and survival implications

Validation of thrombotic risk factors in 1381 patients with essential thrombocythaemia: A multicentre retrospective real-life study

Thrombosis and haemorrhage are frequent in patients with essential thrombocythaemia (ET). The 2016 revised International Prognostic Score for Thrombosis in Essential Thrombocythaemia-thrombosis (r-IPSET-t) score stratifies patients into very-low- (VLR), low- (LR), intermediate- (IR) and high-risk (HR) groups. We validated the r-IPSET-t in the biggest population of patients with ET (n = 1381) to date and found it to be a better fit than the earlier IPSET-t score. With an average follow-up of 87.7 months, there were 0.578 thrombotic events/person-year and 0.286 bleeding events/person-year after diagnosis. The 10-year thrombosis-free survival was 88% and 99% for the r-IPSET-t LR and VLR groups (p < 0.001). Cytoreduction was a thrombotic risk factor in younger patients (aged <60 years, hazard ratio 9.49, p = 0.026; aged ≥60 years, hazard ratio 1.04, p = 0.93). In multivariable Cox regression analysis, anti-aggregation after diagnosis was protective for thrombosis (hazard ratio 0.31, p = 0.005) but a risk factor for major bleeding (hazard ratio 10.56, p = 0.021). Of the IPSET-t HR and LR groups, 132/780 and 249/301 were re-classified as LR and VLR respectively (p < 0.001). The European LeukemiaNET (ELN) does not recommend aspirin for VLR patients but in this real-life analysis 83.1% of VLR patients received it. Our results validate the r-IPSET-t score as more predictive for thrombosis than the ELN-recommended IPSET-t and raise concerns about unnecessary cytoreductive and anti-aggregative therapy.

The Essential Thrombocythemia in 2020: What We Know and Where We Still Have to Dig Deep

The Essential Thrombocythemia is a Chronic Philadelphia-negative Myeloproliferative Neoplasm characterized by a survival curve that is only slightly worse than that of age- and sex-adjusted healthy population. The criteria for diagnosis were reviewed in 2016 by WHO. The incidence varies from 0.2 to 2.5:100 000 people per year, with a prevalence of 38 to 57 cases per 100 000 people. The main characteristics of ET are the marked thrombocytosis and the high frequency of thrombosis. The spectrum of symptoms is quite wide, but fatigue results to be the most frequent. Thrombosis is frequently observed, often occurring before or at the time of diagnosis. The classification of thrombotic risk has undergone several revisions. Recently, the revised-IPSET-t has distinguished 4 risk classes, from very low risk to high risk. Driver mutations seem to influence thrombotic risk and prognosis, while the role of sub-driver mutations still remains uncertain. Antiplatelet therapy is recommended in all patients aged ⩾ 60 years and in those with a positive history of thrombosis or with cardiovascular risk factors, while cytoreductive therapy with hydroxyurea or interferon is reserved for high-risk patients.

Essential Thrombocythemia and Acquired von Willebrand Syndrome: The Shadowlands between Thrombosis and Bleeding

Over the past decade, new insights have emerged on the pathophysiology of essential thrombocythemia (ET), its clinical management, and associated thrombohemostatic disturbances. Here, we review the latest diagnostic and risk stratification modalities of ET and its therapeutics. Moreover, we discuss the clinical evidence-based benefits, deriving from major clinical trials, of using cytoreductive therapy and antiplatelet agents to lower the risk of fatal vascular events. Also, we focus on the condition of extreme thrombocytosis (>1000 × 10⁹/L) and bleeding risk, the development and pathogenesis of acquired von Willebrand syndrome, and the clinical approach to this paradoxical scenario in ET.

The Essential Thrombocythemia, Thrombotic Risk Stratification, and Cardiovascular Risk Factors

Essential thrombocythemia is a rare hematological malignancy with good overall survival, but moderate to high risk of developing arterial or venous thrombosis lifelong. Different thrombotic risk scores for patients with essential thrombocythemia have been proposed, but only one of them (the IPSET-t scoring system) takes into account the classical cardiovascular risk factors as one of the scoring items. Currently, in clinical practice, the presence of cardiovascular risk factors in patients with diagnosis of ET rarely determines the decision to initiate cytoreductive therapies. In our study, we compared different risk models to estimate the thrombotic risk of 233 ET patients and the role of specific driver mutations and evaluated the impact that conventional cardiovascular risk factors (hypertension, cigarette smoking, diabetes, obesity, and dyslipidaemia) have on thrombotic risk in patients with ET. Perspective studies conducted on a polycentric large cohort of patients should be conducted to estimate the impact of cardiovascular risk factors in determining thrombosis in ET patients, evaluating the opportunity of initiating a cytoreductive therapy in patients with cardiovascular risk factors, even if classified into low to moderate risk groups according to other scoring systems.

Inhibitors of the blood coagulation process in patients with essential thrombocythemia

: The aim of the study was to assess the activity of protein C, protein S and tissue factor pathway inhibitor in relation to the risk factors for thrombotic complications in patients with essential thrombocythemia.The study group consisted of 45 newly diagnosed patients with essential thrombocythemia. Protein S activity was determined by chromogenic method. Activities of protein C and tissue factor pathway inhibitor (TFPI) were determined using ELISAs.Significantly lower protein C and protein S activity but higher TFPI activity were found in patients with ET in comparison with the control group. TFPI activity was higher in women as compared to men, and in patients over 60 years of age compared with patients below 60 years of age. TFPI activity was higher in patients with leukocytes count at least 11 g/l than in patients with leukocytes count below 11 g/l and the difference almost reached statistical significance. Significantly lower protein C activity was found in patients with the JAK2V617F mutation, in comparison with essential thrombocythemia patients JAK2V617F (-).The reduced protein C and protein S activity may be one of the pathogenic factors of increased prothrombotic state in essential thrombocythemia patients. The decreased protein C activity in patients with the JAK2 V617F mutation seems to confirm the significant role of this mutation in the pathogenesis of thrombotic complications in essential thrombocythemia patients. Significantly increased TFPI activity in essential thrombocythemia patients above 60 years of age and with leukocyte count above 11 g/l expresses the activation of the compensatory mechanism for increased prothrombotic activity.