Influence of platelet and white blood cell counts on major thrombosis – analysis from a patient registry in essential thrombocythemia

Molecular landscape of the JAK2 gene in chronic myeloproliferative neoplasm patients from the state of Amazonas, Brazil

JAK2V617F (dbSNP: rs77375493) is the most frequent and most-studied variant in BCR::ABL1 negative myeloproliferative neoplasms and in the JAK2 gene. The present study aimed to molecularly characterize variants in the complete coding region of the JAK2 gene in patients with BCR::ABL1 negative chronic myeloproliferative neoplasms. The study included 97 patients with BCR::ABL1 negative myeloproliferative neoplasms, including polycythemia vera (n=38), essential thrombocythemia (n=55), and myelofibrosis (n=04). Molecular evaluation was performed using conventional PCR and Sanger sequencing to detect variants in the complete coding region of the JAK2 gene. The presence of missense variants in the JAK2 gene including rs907414891, rs2230723, rs77375493 (JAK2V617F), and rs41316003 were identified. The coexistence of variants was detected in polycythemia vera and essential thrombocythemia. Thus, individuals with high JAK2V617F variant allele frequency (≥50% VAF) presented more thrombo-hemorrhagic events and manifestations of splenomegaly compared with those with low JAK2V617F variant allele frequency (<50% VAF). In conclusion, individuals with BCR::ABL1 negative neoplasms can display >1 variant in the JAK2 gene, especially rs2230722, rs2230724, and rs77375493 variants, and those with high JAK2V617F VAF show alterations in the clinical-laboratory profile compared with those with low JAK2V617F VAF.

Evaluation of systemic immune-inflammation index in acute deep vein thrombosis: A propensity-matched

OBJECTIVE

Deep vein thrombosis (DVT) progressing to pulmonary embolism is an important cause of mortality and morbidity worldwide. At present, color Doppler ultrasound is the most effective examination method for the diagnosis of DVT. The systemic immune-inflammation index (SII) has been introduced as a new indicator of comprehensive systemic immune thrombosis and inflammatory status in the body. We believe that the SII might be more specific and sensitive than the neutrophil-lymphocyte ratio (NLR) and platelet-lymphocyte ratio (PLR). In the present study, we aimed to evaluate the predictive potential of the SII, NLR, and PLR in the diagnosis of DVT.

METHODS

The data of patients aged >18 years who were diagnosed with acute DVT in our hospital between June 2017 and June 2021 were retrospectively reviewed. During the study period, the data of 155 patients with acute DVT and 179 healthy control patients without DVT were included in the study. A propensity score analysis (1:1) was performed to eliminate differences between the two groups, and 63 patients from each group were included in the present study.

RESULTS

When the complete blood count parameters were examined between the patients with acute DVT and the control group, the hemoglobin, hematocrit, lymphocyte count, and platelet distribution width were lower in the DVT group. In contrast, the white blood cell count, neutrophil count, platelet count, NLR, PLR, SII, and mean platelet volume were higher in the DVT group. The changes in hemoglobin (P = .001), hematocrit (P = .001), white blood cell count (P = .001), neutrophil count (P = .001), lymphocyte count (P = .001), platelet count (P = .001), NLR (P=.001), PLR (P = .001), SII (P = .001), and mean platelet volume (P = .031) were significant on statistical analysis. However, the changes in the platelet distribution width were not significant (P = .794). The area under the curve for the NLR and PLR was 0.797 (95% confidence interval [CI], 0.747-0.848; P < .001) and 0.788 (95% CI, 0.737-0.840; P = .01), respectively. The sensitivity and specificity for an NLR >3.00 was 71.0% and 68.7%, respectively. The sensitivity and specificity for a PLR >142.66 was 70.3% and 68.5%, respectively. The area under the curve for SII was 0.861 (95% CI, 0.820-0.902; P < .001), with a sensitivity of 78.1% and specificity of 73.1% for an SII >755.54.

CONCLUSIONS

The SII can be used as an auxiliary diagnostic test for patients with venous thrombosis. This parameter is superior to the NLR and PLR with high sensitivity and specificity for patients with venous thrombosis.

Combination of neutrophil to lymphocyte ratio, platelet to lymphocyte ratio with plasma D-dimer level to improve the diagnosis of deep venous thrombosis (DVT) following ankle fracture

PURPOSE

To investigate the relationship between neutrophil to lymphocyte ratio (NLR)/platelet to lymphocyte ratio (PLR) with deep venous thrombosis (DVT) following ankle fracture and the diagnostic ability of combination model.

METHOD

This retrospective study included patients with a diagnosis of ankle fracture who had undergone preoperative Duplex ultrasound (DUS) examination for detecting the possible deep venous thrombosis (DVT). The variables of interest, the calculated NLR and PLR and others (demographics, injury, lifestyles and comorbidities) were extracted from the medical records. Two independent multivariate logistics regression models were used to detect the relationship between NLR or PLR and DVT. If any, combination diagnostic model was constructed and its diagnostic ability was evaluated.

RESULTS

There were 1103 patients included, and 92 (8.3%) were found to have preoperative DVT. The NLR and PLR, which had respective optimal cut-off point of 4 and 200, were significantly different between patients with and without DVT either in continuous or categorical variable. After adjustment for covariates, both NLR and PLR were identified as independent risk factors associated with DVT, with odd ratio of 2.16 and 2.84, respectively. The combination diagnostic model, including NLR, PLR and D-dimer, demonstrated to significantly improved the diagnostic performance than any one alone or combined (all P < 0.05), and the area under the curve was 0.729 (95% CI 0.701-0.755).

CONCLUSION

We concluded the relatively low incidence rate of preoperative DVT after ankle fracture, and both NLR and PLR were independently associated with DVT. The combination diagnostic model can be considered as a useful auxiliary tool for identifying high-risk patients for DUS examination.

Combination of platelet-to-lymphocyte ratio and D-dimer for the identification of cardiogenic cerebral embolism in non-valvular atrial fibrillation

Background

Non-valvular atrial fibrillation (NVAF) is the most common cause of cardiogenic cerebral embolism (CCE). However, the underlying mechanism between cerebral embolism and NVAF is indefinite, and there is no effective and convenient biomarker to identify potential risk of CCE in patients with NVAF in clinic. The present study aims to identify risk factors for interpreting the potential association of CCE with NVAF and providing valuable biomarkers to predict the risk of CCE for NVAF patients.

Methods

641 NVAF patients diagnosed with CCE and 284 NVAF patients without any history of stroke were recruited in the present study. Clinical data including demographic characteristics, medical history, and clinical assessments, were recorded. Meanwhile, Blood cell counts, lipid profiles, high-sensitivity C-reactive protein, and coagulation function-related indicators were measured. Least absolute shrinkage and selection operator (LASSO) regression analysis was utilized to build a composite indicator model based on the blood risk factors.

Results

(1) CCE patients had significantly increased neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio (PLR), and D-dimer levels as compared with patients in the NVAF group, and these three indicators can distinguish CCE patients from ones in the NVAF group with an area under the curve (AUC) value of over 0.750, respectively. (2) Using the LASSO model, a composite indicator, i.e., the risk score, was determined based on PLR and D-dimer and displayed differential power for distinguishing CCE patients from NVAF patients with an AUC value of over 0.934. (3) The risk score was positively correlated with the National Institutes of Health Stroke Scale and CHADS2 scores in CCE patients. (4) There was a significant association between the change value of the risk score and the recurrence time of stroke in initial CCE patients.

Conclusions

The PLR and D-dimer represent an aggravated process of inflammation and thrombosis in the occurrence of CCE after NVAF. The combination of these two risk factors can contribute to identifying the risk of CCE for patients with NVAF with an accuracy of 93.4%, and the greater in change of composite indicator, the shorter in the recurrence of CCE for NVAF patients.

Functional role and molecular mechanisms underlying prohibitin 2 in platelet mitophagy and activation

Platelet mitophagy is a major pathway involved in the clearance of injured mitochondria during hemostasis and thrombosis. Prohibitin 2 (PHB2) has recently emerged as an inner mitochondrial membrane receptor involved in mitophagy. However, the mechanisms underlying PHB2-mediated platelet mitophagy and activation are not completely understood. PHB2 is a highly conserved inner mitochondrial membrane protein that regulates mitochondrial assembly and function due to its unique localization on the mitochondrial membrane. The present study aimed to investigate the role and mechanism underlying PHB2 in platelet mitophagy and activation. Phorbol-12-myristate-13-acetate (PMA) was used to induce MEG-01 cells maturation and differentiate into platelets following PHB2 knockdown. Cell Counting Kit-8 assays were performed to examine platelet viability. Flow cytometry was performed to assess platelet mitochondrial membrane potential. RT-qPCR and western blotting were conducted to measure mRNA and protein expression levels, respectively. Subsequently, platelets were exposed to CCCP and the role of PHB2 was assessed. The results of the present study identified a crucial role for PHB2 in platelet mitophagy and activation, suggesting that PHB2-mediated regulation of mitophagy may serve as a novel strategy for downregulating the expression of platelet activation genes. Although further research into mitophagy is required, the present study suggested that PHB2 may serve as a novel therapeutic target for thrombosis-related diseases due to its unique localization on the mitochondrial membrane.

Low-Risk Essential Thrombocythemia: A Comprehensive Review

Essential thrombocythemia (ET) is a chronic myeloproliferative neoplasm characterized by a persistently elevated platelet count in the absence of a secondary cause. The clinical consequences of uncontrolled thrombocytosis can include both thrombosis and hemorrhage. Patients with features conferring a “high risk” of vascular events benefit from reduction of the platelet count through cytoreductive therapy. The management of patients who lack such high-risk features has until recently been less well defined, but it is now apparent that many require minimal or even no intervention. In this review, we discuss the diagnostic pathway for younger patients with unexplained thrombocytosis, including screening molecular investigations, the role of bone marrow biopsy, and investigations in those patients negative for the classic myeloproliferative neoplasm driver mutations (JAK2, CALR, MPL). We discuss conventional and novel risk stratification methods in essential thrombocythemia and how these can be best applied in clinical practice, particularly in the era of more comprehensive genomic testing. The treatment approach for “low risk” patients is discussed including antiplatelets and the options for cytoreductive therapy, if indicated, together with areas of clinical need for future study.

Persistent leukocytosis in polycythemia vera is associated with disease evolution but not thrombosis

There are unresolved questions regarding the association between persistent leukocytosis and risk of thrombosis and disease evolution in polycythemia vera (PV), as much of the published literature on the topic does not appropriately use repeated-measures data or time-dependent modeling to answer these questions. To address this knowledge gap, we analyzed a retrospective database of 520 PV patients seen at 10 academic institutions across the United States. Taking hematologic laboratory data at ∼3-month intervals (or as available) for all patients for duration of follow-up, we used group-based trajectory modeling to identify latent clusters of patients who follow distinct trajectories with regard to their leukocyte, hematocrit, and platelet counts over time. We then tested the association between trajectory membership and hazard of 2 major outcomes: thrombosis and disease evolution to myelofibrosis, myelodysplastic syndrome, or acute myeloid leukemia. Controlling for relevant covariates, we found that persistently elevated leukocyte trajectories were not associated with the hazard of a thrombotic event (P = .4163), but were significantly associated with increased hazard of disease evolution in an ascending stepwise manner (overall P = .0002). In addition, we found that neither hematocrit nor platelet count was significantly associated with the hazard of thrombosis or disease evolution.

Austrian recommendations for the management of essential thrombocythemia

According to the World Health Organization (WHO) classification, essential (primary) thrombocythemia (ET) is one of several Bcr-Abl negative chronic myeloproliferative neoplasms (MPN). The classical term MPN covers the subcategories of MPN: ET, polycythemia vera (PV), primary myelofibrosis (PMF), and prefibrotic PMF (pPMF). ET is marked by clonal proliferation of hematopoietic stem cells, leading to a chronic overproduction of platelets. At the molecular level a JAK2 (Janus Kinase 2), calreticulin, or MPL mutation is found in the majority of patients. Typical ongoing complications of the disease include thrombosis and hemorrhage. Primary and secondary prevention of these complications can be achieved with platelet function inhibitors and various cytoreductive drugs including anagrelide, hydroxyurea and interferon. After a long follow up, in a minority of ET patients the disease transforms into post-ET myelofibrosis or secondary leukemia. Overall, life expectancy with ET is only slightly decreased.

Impact of platelets on major thrombosis in patients with a normal white blood cell count in essential thrombocythemia

Objectives

Cell counts have a significant impact on the complex mechanism of thrombosis in patients with essential thrombocythemia (ET). We recently demonstrated a considerable impact of white blood cell (WBC) counts on thrombotic risk in patients with optimized platelet counts by analysing a large anagrelide registry. In contrast, the current analysis of the registry aimed to estimate the influence of platelet counts on thrombotic risk in patients with optimized WBC counts.

Methods

Cox regression analysis and Kaplan‐Meier plot were applied on all patients in the registry with optimized WBC counts.

Results

By using the calculated cut‐off of 593 G/L for platelets, Cox regression analysis revealed a clear influence of elevated platelet counts on the occurrence of a major thrombotic event (P < .001). A Kaplan‐Meier plot revealed a markedly shorter time to a major thrombotic event for patients with platelet counts above the cut‐off (P < .001).

Conclusions

The data show clear impact of platelet lowering on the thrombotic risk in ET patients with normal WBC counts. Therefore, selective platelet lowering with anagrelide appears sufficient for thrombotic risk reduction in WHO‐diagnosed ET patients lacking leukocytosis.

Leukocytosis and thrombosis in essential thrombocythemia and polycythemia vera: a systematic review and meta-analysis

In the last years, a growing amount of evidence has been produced regarding the role of leukocytosis as a risk factor for thrombosis in patients with myeloproliferative neoplasms, predominantly in polycythemia vera (PV) and essential thrombocythemia (ET). Results from epidemiologic studies on this issue, however, are inconclusive. We conducted a systematic review and meta-analysis of articles published in the last 12 years addressing the issue, according to a predefined protocol. Forty-one articles analyzing >30 000 patients met our inclusion criteria and were deemed of acceptable methodologic quality. In addition to data on thrombosis, data were collected on bleeding, hematologic evolution, secondary cancer, and death. The relative risk (RR) of thrombosis in the presence of leukocytosis was 1.59 (95% CI, 1.40-1.80), mainly accounted for by ET (RR, 1.65; 95% CI, 1.43-1.91) and arterial thrombosis (RR, 1.45; 95% CI, 1.13-1.86) subgroups; the effect was not significant in venous thrombosis alone. Sensitivity analyses considering recurrent events as well as white blood cell estimates adjusted or unadjusted for confounding factors confirmed the primary results. In addition, the pooled RR of studies that tested white blood cell counts in time-dependent models suggested a causative effect of leukocytes in the mechanism that triggers thrombosis. The effect of leukocytosis on bleeding (RR, 1.87; 95% CI, 1.26-2.77) and death (RR, 1.89; 95% CI, 1.59-2.23) was confirmed, whereas conclusions on hematologic evolutions and solid tumors were uncertain. To confirm the accuracy of these results, an investigation on individual patient data in a large collective archive of homogeneous patients is warranted.

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.

Essential thrombocythemia: a hemostatic view of thrombogenic risk factors and prognosis

Essential thrombocythemia (ET) is a classical myeloproliferative neoplasm that is susceptible to hypercoagulable state due to impaired hemostatic system, so that thrombotic complications are the leading cause of mortality in ET patients. The content used in this article has been obtained by the PubMed database and Google Scholar search engine from English-language articles (2000-2019) using the following keywords: "Essential thrombocythemia," "Thrombosis," "Risk factors" and "Hemostasis. In this neoplasm, the count and activity of cells such as platelets, leukocytes, endothelial cells, as well as erythrocytes are increased, which can increase the risk of thrombosis through rising intercellular interactions, expression of surface markers, and stimulation of platelet aggregation. In addition to these factors, genetic polymorphisms in hematopoietic stem cells (HSCs), including mutations in JAK2, CALR, MPL, or genetic abnormalities in other genes associated with the hemostatic system may be associated with increased risk of thrombotic events. Moreover, disruption of coagulant factors can pave the way for thrombogeneration. Therefore, the identification of markers related to cell activation, genetic abnormalities, or alternation in the coagulant system can be used together as diagnostic and prognostic markers for the occurrence of thrombosis among ET patients. Thus, because thrombotic complications are the main factors of mortality in ET patients, a hemostatic viewpoint and risk assessment of cellular, genetic, and coagulation factors can have prognostic value and contribute to the choice of effective treatment and prevention of thrombosis.

Comparative Evaluation of Median Versus Youden Index Dichotomization Methods: Exposure-Response Analysis of Mycophenolic Acid and Acyl-Glucuronide Metabolite

BACKGROUND AND OBJECTIVES

Dichotomization of pharmacokinetic exposure measures in exposure-response relationship studies provides results that are interpretable in clinical care. Several methods exist in the literature on how to define the cut-off values needed for the dichotomization process. Commonly, the sample median is utilized to define the dichotomizing value; however, statistical methods based on the exposure metric and its association with the outcome are argued to result in a more proper definition of the optimal cut-point. The Youden index is a recommended statistical method to define the cut-off value. The current analysis objective is to compare the dichotomization results based on the Youden index versus median methods.

METHODS

Utilizing mycophenolic acid (MPA) exposure data and its related acute rejection and leukopenia outcome variables, the current study compared the MPA exposure-response relationship outcomes when MPA exposure is dichotomized via the Youden index versus median methods. Univariate logistic models were utilized to quantify the relationships between MPA exposure, including total MPA, unbound MPA, and the acyl-glucuronide metabolite of MPA, and the probabilities of acute rejection and leukopenia.

RESULTS

The overall trend of the results of the logistic models demonstrated a general similarity in the inferred exposure-response associations when considering either the Youden index-based or the median-based dichotomization methods.

CONCLUSION

The results demonstrated in this analysis suggest that both the Youden index and the median methods provide similar conclusions when dichotomization of a continuous variable is considered. However, confirmation of these conclusions comes from future powered studies that include a larger number of subjects.

Highly reduced survival in essential thrombocythemia and polycythemia vera patients with vascular complications during follow-up

OBJECTIVE

To explore the relative importance of risk factors, treatments, and blood counts for the occurrence of vascular complications and their impact on life expectancy in essential thrombocythemia (ET) and polycythemia vera (PV).

METHODS

Nested case-control study within the Swedish MPN registry. From a cohort of 922 ET patients and 763 PV patients, 71 ET and 81 PV cases with vascular complications were compared with matched controls.

RESULTS

Incidence of vascular complications was 2.0 and 3.4 events per 100 patient-years in ET and PV, respectively. At diagnosis, no significant risk factor differences were observed between cases and controls in neither of the diseases. At the time of vascular event, ET complication cases did not differ significantly from controls but in PV, cases had significantly higher WBCs and were to a lesser extent treated with anti-thrombotic and cytoreductive therapy. Life expectancy was significantly decreased in both ET and PV cases compared with controls.

CONCLUSIONS

The risk of vascular complications is high in both ET and PV, and these complications have a considerable impact on life expectancy. The protective effect of anti-thrombotic and cytoreductive therapy for vascular complications in PV underscores the importance of avoiding undertreatment.

Guidelines on the Use of Therapeutic Apheresis in Clinical Practice - Evidence-Based Approach from the Writing Committee of the American Society for Apheresis: The Eighth Special Issue

The American Society for Apheresis (ASFA) Journal of Clinical Apheresis (JCA) Special Issue Writing Committee is charged with reviewing, updating and categorizing indications for the evidence-based use of therapeutic apheresis (TA) in human disease. Since the 2007 JCA Special Issue (Fourth Edition), the committee has incorporated systematic review and evidence-based approaches in the grading and categorization of apheresis indications. This Eighth Edition of the JCA Special Issue continues to maintain this methodology and rigor in order to make recommendations on the use of apheresis in a wide variety of diseases/conditions. The JCA Eighth Edition, like its predecessor, continues to apply the category and grading system definitions in fact sheets. The general layout and concept of a fact sheet that was introduced in the Fourth Edition, has largely been maintained in this edition. Each fact sheet succinctly summarizes the evidence for the use of TA in a specific disease entity or medical condition. The Eighth Edition comprises 84 fact sheets for relevant diseases and medical conditions, with 157 graded and categorized indications and/or TA modalities. The Eighth Edition of the JCA Special Issue seeks to continue to serve as a key resource that guides the utilization of TA in the treatment of human disease.

A phase III randomized, multicentre, double blind, active controlled trial to compare the efficacy and safety of two different anagrelide formulations in patients with essential thrombocythaemia - the TEAM-ET 2·0 trial

Anagrelide is an established treatment option for essential thrombocythaemia (ET). A prolonged release formulation was developed with the aim of reducing dosing frequency and improving tolerability, without diminishing efficacy. This multicentre, randomized, double blind, active‐controlled, non‐inferiority trial investigated the efficacy, safety and tolerability of anagrelide prolonged release (A‐PR) over a reference product in high‐risk ET patients, either anagrelide‐naïve or ‐experienced. In a 6 to 12‐week titration period the individual dose for the consecutive 4‐week maintenance period was identified. The primary endpoint was the mean platelet count during the maintenance period (3 consecutive measurements, day 0, 14, 28). Of 112 included patients 106 were randomized. The mean screening platelet counts were 822 × 10⁹/l (95% confidence interval (CI) 707–936 × 10⁹/l) and 797 × 10⁹/l (95% CI 708–883 × 10⁹/l) for A‐PR and the reference product, respectively. Both treatments effectively reduced platelet counts, to mean 281 × 10⁹/l for A‐PR (95% CI 254–311) and 305 × 10⁹/l (95% CI 276–337) for the reference product (P < 0·0001, for non‐inferiority). Safety and tolerability were comparable between both drugs. The novel prolonged‐release formulation was equally effective and well tolerated compared to the reference product. A‐PR provides a more convenient dosing schedule and will offer an alternative to licensed immediate‐release anagrelide formulations.

The role of platelet hyperreactivity in venous thromboembolism after total knee arthroplasty in elderly population without pharmacologic prophylaxis: A single-center study

INTRODUCTION

While it is suggested that platelet hyperreactivity plays a role in the arterial thrombi, its link with venous thromboembolism (VTE) is not well defined. Aggregometry using low concentrations of agonists is proposed as a reliable method to detect hyperreactivity. The aim of this study was to examine whether platelet hyperreactivity affects the development of VTE after total knee arthroplasty (TKA).

METHODS

Total 150 elderly patients without VTE history were enrolled. Mechanical prophylaxis was used for VTE after TKA. We performed platelet aggregation using Chrono-log (Chrono-log Corporation, USA) in the presence of low concentrations of ADP (1.0 μmol/L) and epinephrine (0.4, 1.0 μmol/L), and measured maximal aggregation (%).

RESULTS

At 0.4 μmol/L epinephrine, 69.3%, 15.3%, and 15.3% displayed low (<40%), moderate (40-60%), and high (>60%) levels of aggregation, respectively. The proportion of high level of aggregation was 36.7%, 30.7% at 1.0 μmol/L of epinephrine and ADP, respectively. The incidence of VTE was higher in the moderate/high aggregation group (10/46, 21.7%) than in the low aggregation group (1/104, 1.0%) at 0.4 μmol/L epinephrine (P < 0.0001). In predicting postoperative VTE, sensitivity and specificity of ≥40% aggregation at 0.4 μmol/L epinephrine were 90.9% and 74.1%. Higher mean platelet volume and lower volume of blood loss were seen in the high aggregation group than in the low aggregation group.

CONCLUSION

Aggregation response to 0.4 μmol/L epinephrine is an optimal assay to classify platelet activity. Platelet hyperreactivity may increase the risk of postoperative VTE in an elderly population, and can be an indication of pharmacologic prophylaxis.

Response to aspirin therapy in patients with myeloproliferative neoplasms depends on the platelet count

Patients with myeloproliferative neoplasms (MPN) are at an increased risk of thrombotic events even during antiplatelet therapy with aspirin. In the current study, we sought to investigate the association of the platelet count with the inhibitory potential of antiplatelet therapy in MPN. We determined arachidonic acid (AA)- and adenosine diphosphate (ADP)-inducible platelet reactivity by multiple electrode aggregometry in 93 patients with essential thrombocythemia, polycythemia vera or primary myelofibrosis. In patients without aspirin therapy (n = 44), the platelet count did not correlate with platelet aggregation. In aspirin-treated patients (n = 49), we observed a moderate correlation of residual AA-inducible platelet aggregation with the platelet count (r = 0.49; P < 0.001). Further, patients with high on-treatment residual platelet reactivity to AA (HRPR AA) had a significantly higher platelet count than patients without HRPR AA (547 × 10⁹/L [340 - 644 × 10⁹/L] vs 358 × 10⁹/L [242 - 501 × 10⁹/L], P = 0.01). Receiver-operating characteristic curve analysis revealed a platelet count of ≥317 × 10⁹/L as best threshold to distinguish between patients without and with HRPR AA (area under the curve: 0.73). After adding the direct ADP P2Y₁₂ inhibitor cangrelor to blood samples from all 93 patients in vitro, residual ADP-inducible platelet reactivity correlated weakly with the platelet count (r = 0.26, P = 0.01), but the platelet count did not differ significantly between patients with and without HRPR ADP (396 × 10⁹/L [316 - 644 × 10⁹/L] vs 340 × 10⁹/L [241 - 489 × 10⁹/L]; P = 0.2). In conclusion, our findings suggest that the extent of platelet inhibition by aspirin in patients with MPN at least in part depends on their individual platelet count.

Platelet characteristics in patients with essential thrombocytosis

BACKGROUND

Essential thrombocytosis (ET) is a myeloproliferative disorder characterized by an increased platelet count. ET is associated with an increased risk of thrombosis, and procoagulant features of the disease may include an increased number of reactive reticulated platelets and an increased aggregation potential. We aimed to explore the association between platelet count, platelet turnover, and platelet aggregation in patients with ET.

METHODS

We included 24 ET patients who discontinued antiplatelet therapy prior to blood sampling. Reticulated platelets were assessed as immature platelet count (IPC) and immature platelet fraction by automated flow cytometry (Sysmex XE-5000). Platelet aggregation was investigated by impedance aggregometry (Multiplate^® Analyzer) and aggregation potential by flow cytometry (NAVIOS).

RESULTS

Our results showed that ET patients had increased IPC compared to healthy individuals (median 12.3 vs. median 6.9, P < 0.0001). Furthermore, a positive correlation between platelet count and impedance aggregation was demonstrated using arachidonic acid (r = 0.48, P = 0.02), thrombin-receptor-activating-peptide (r = 0.46, P = 0.03) and adenosine diphosphate (r = 0.56, P = 0.007) as agonists. Finally, an increased aggregation potential was demonstrated in ET patients compared to healthy individuals.

CONCLUSIONS

The study showed that ET patients compared to healthy individuals have an increased amount of reticulated platelets and increased aggregation potential. These findings might in part explain the increased thromboembolic risk in patients with ET. © 2018 International Clinical Cytometry Society.

Clinico-hematological profile and thrombotic/hemorrhagic events in 150 chinese patients with essential thrombocythemia

Essential thrombocythemia (ET) is an uncommon chronic myeloproliferative disorder with no cure. Patients with ET are at risk of different complications, and currently there are no optimal prognostic standards to predict severe post-diagnosis complications such as thrombosis and hemorrhage. In this study, we retrospectively analyzed the full set of clinical data from 150 Chinese patients with ET enrolled from 2013 to 2016. We discovered that neutrophil-to-lymphocyte ratio (NLR), along with other known clinical parameters such as age, leukocyte count, incidence of thrombotic events is higher in patients with JAK2 V617F mutation. NLR is also higher in patients at high-risk stratification of thrombosis. Multivariate analysis showed that age (P = 0.001, 95% CI 1.023-1.089) and JAK2 V617F mutation (P = 0.003, 95% CI 1.837-21.035) were independent factors for thrombotic events, while age (P = 0.005, 95% CI 1.019-1.111) was the only predictive factor for hemorrhagic events at diagnosis. For future thrombotic events, multivariate analysis revealed NLR as the best predictive parameter (P < 0.001, 95% CI 1.173-1.486) when compared with other clinical parameters such as age (P = 0.037, 95% CI 1.004-1.126), thrombosis at diagnosis (P = 0.036, 95% CI 1.077-9.099) and WBC count (P = 0.047, 95% CI 1.001-1.109). Further ROC curve and Kaplan Meier analysis validated NLR as better prognostic marker for future thrombotic events and thrombosis-free survival. In summary, our data suggest that NLR parameter may possess great prognostic significance for future thrombosis in ET patients.

Impact of white blood cells on thrombotic risk in patients with optimized platelet count in essential thrombocythemia

OBJECTIVES

Risk of thrombosis is significantly enhanced by both elevated platelet (PLT) and white blood cell (WBC) counts according to a retrospective analysis of a large anagrelide registry in thrombocythemic MPN patients. We were interested in the impact of elevated WBC counts on thrombosis risk in patients where PLT counts were reduced below the calculated cutoff of 574.5 G/L by treatment with anagrelide.

METHODS

Cox regression analysis and Kaplan-Meier plot were applied on all patients in the registry with optimized PLT counts.

RESULTS

Using the calculated cutoff of 9.66 G/L for WBC, Cox regression analysis revealed a clear influence of elevated WBC counts on the occurrence of a major thrombotic event (P = .012). A Kaplan-Meier plot revealed a markedly shorter time to a major thrombotic event for patients with WBC counts above the cutoff (P = .001).

CONCLUSIONS

These data suggest that additional correction of elevated WBC counts is mandatory in patients with optimally managed PLT counts to reduce thrombotic risk. This study is the first investigation in a prospectively observed large patient cohort which was treated homogenously allowing for evaluation of single parameters for an effect on thrombophilia.

Platelet to Lymphocyte Ratio and Neutrophil to Lymphocyte Ratio as Risk Factors for Venous Thrombosis

High platelet to lymphocyte ratio (PLR) and neutrophil to lymphocyte ratio (NLR) are associated with an increased risk of arterial thrombosis, but their role in venous thromboembolism (VTE) has not been fully investigated. A case-control study, of 486 patients with VTE, 100 with cerebral vein thrombosis (CVT), and 299 healthy individuals, was carried out to investigate whether high PLR or NLR values are associated with an increased risk of VTE. Patients with high PLR or NLR did not have an increased risk of VTE (odds ratio [OR] 0.89, 95% confidence interval [CI]: 0.46-1.76; OR: 0.69, 95% CI: 0.34-1.39, respectively) or CVT (OR: 1.65, 95% CI: 0.68-4.00; OR: 0.39, 95% CI: 0.09-1.72, respectively). Subgroups analysis showed that high PLR values were associated with the risk of provoked CVT (OR: 2.65, 95% CI: 1.02-6.92), and there was an interaction with thrombophilia abnormalities (OR: 7.67, 95% CI: 1.67-35.27) in patients with CVT. In conclusion, high PLR and NLR values are not associated with an overall increased risk of VTE or CVT. High PLR values increase the risk of provoked CVT and interact with thrombophilia abnormalities in patients with CVT.

Treatment of essential thrombocythemia in Europe: a prospective long-term observational study of 3649 high-risk patients in the Evaluation of Anagrelide Efficacy and Long-term Safety study

Evaluation of Anagrelide (Xagrid^®) Efficacy and Long-term Safety, a phase IV, prospective, non-interventional study performed in 13 European countries enrolled high-risk essential thrombocythemia patients treated with cytoreductive therapy. The primary objectives were safety and pregnancy outcomes. Of 3721 registered patients, 3649 received cytoreductive therapy. At registration, 3611 were receiving: anagrelide (Xagrid^®) (n=804), other cytoreductive therapy (n=2666), or anagrelide + other cytoreductive therapy (n=141). The median age was 56 vs. 70 years for anagrelide vs. other cytoreductive therapy. Event rates (patients with events/100 patient-years) were 1.62 vs. 2.06 for total thrombosis and 0.15 vs. 0.53 for venous thrombosis. Anagrelide was more commonly associated with hemorrhage (0.89 vs. 0.43), especially with anti-aggregatory therapy (1.35 vs. 0.33) and myelofibrosis (1.04 vs. 0.30). Other cytoreductive therapies were more associated with acute leukemia (0.28 vs. 0.07) and other malignancies (1.29 vs. 0.44). Post hoc multivariate analyses identified increased risk for thrombosis with prior thrombohemorrhagic events, age ≥65, cardiovascular risk factors, or hypertension. Risk factors for transformation were prior thrombohemorrhagic events, age ≥65, time since diagnosis, and platelet count increase. Safety analysis reflected published data, and no new safety concerns for anagrelide were found. Live births occurred in 41/54 pregnancies (76%). clinicaltrials.gov Identifier: 00567502.

The Use of Anagrelide in Myeloproliferative Neoplasms, with Focus on Essential Thrombocythemia

Anagrelide (ANA) is a drug with specific platelet-lowering activity, used primarily in ET, registered as a second-line drug in essential thrombocythemia (ET) in Europe and in some countries as first-line therapy, in USA licensed by FDA for thrombocythemia in myeloproliferative neoplasms (MPN). The platelet-lowering efficacy is similar to that of hydroxycarbamide (HC), around 70 % complete response and 90 % partial response. Side effects are common, especially headache and tachycardia, but usually subside or disappear within a few weeks. Around 20 % of patients stop ANA therapy due to side effects or insufficient response. Studies of treatment patterns in Europe show that ANA is preferentially given to younger patients, probably because of the concern for a possible leukemogenic effect of the common first-line drug, HC. Only two randomized studies have compared the efficacy of ANA and HC in preventing thrombosis and haemorrhage, the larger of them showing a slightly better efficacy of HC, the other showing non-inferiority of ANA to HC. A recent observational 5-year study of 3600 patients shows a low and basically similar efficacy of ANA and other cytoreductive therapies in ET. ANA does not appear to inhibit fibrosis development, and probably due to its anticoagulation properties, the combination of ASA and ANA produces an increased rate of haemorrhage. Combination of ANA with HC or interferon (IFN) is feasible and effective in patients with insufficient platelet response to mono-therapy.

Recurrence of Thrombin-Injected Pseudoaneurysms Under Ultrasound Guidance: A 10-Year Retrospective Analysis

OBJECTIVES

Ultrasound-guided thrombin injection has become standard treatment for extremity pseudoaneurysms. Our specific aims were to determine the procedural success rate, the procedural complication rate, and the factors associated with pseudoaneurysm recurrence.

METHODS

A total of 262 consecutive cases of ultrasound-guided thrombin repair of pseudoaneurysms were identified between January 1, 2006, and March 20, 2016. The procedural and follow-up ultrasound studies were reviewed. Outcomes of interest included procedural success (defined as complete thrombosis at the time of injection and on a follow-up examination), incomplete pseudoaneurysm thrombosis, and postprocedural recurrence. Postprocedural pseudoaneurysm recurrences were compared to procedural successes with regard to patient demographics, pseudoaneurysm characteristics, amount of thrombin injected, and periprocedural laboratory values.

RESULTS

Procedural success occurred in 85.7% of cases. Complications occurred in 3.0% of cases. The mean patient age ± SD was 72.3 ± 11.3 years. The median amount of thrombin injected was 500 U (interquartile range, 400 U). The median follow-up time was 1 day (interquartile range, 0 days). A pseudoaneurysm size of 2 cm or larger and thrombocytopenia were significant independent predictors of pseudoaneurysm recurrence (P = .003 and .03, respectively). The odds ratios for pseudoaneurysm recurrence were 2.29 for pseudoaneurysm size of 2 cm or larger (P = .03) and 1.04 for thrombocytopenia (P = .04).

CONCLUSIONS

Thrombin injection of pseudoaneurysms is an off-label procedure with few complications and a high success rate. Follow-up imaging is recommended in all pseudoaneurysms that are 2 cm or larger and in patients with thrombocytopenia.