Why thromboembolism occurs in some patients with thrombocytopenia and treatment strategies

Predicting the risk of pulmonary embolism in patients with tuberculosis using machine learning algorithms

BACKGROUND

This study aimed to develop predictive models with robust generalization capabilities for assessing the risk of pulmonary embolism in patients with tuberculosis using machine learning algorithms.

METHODS

Data were collected from two centers and categorized into development and validation cohorts. Using the development cohort, candidate variables were selected via the Recursive Feature Elimination (RFE) method. Five machine learning algorithms, logistic regression (LR), random forest (RF), extreme gradient boosting (XGBoost), light gradient boosting machine (LightGBM), and support vector machine (SVM), were utilized to construct the predictive models. Model performance was evaluated through nested cross-validation and area under the curve (AUC) metrics, supplemented by interpretations using Shapley Additive explanations (SHAP) and line charts of AUC values. Models were subjected to external validation using an independent validation group, facilitating the early identification and management of pulmonary embolism risks in tuberculosis patients.

RESULTS

Data from 694 patients were used for model development, and 236 patients from the validation group met the enrollment criteria. The optimal subset of variables identified included D-dimer, smoking status, dyspnea, age, sex, diabetes, platelet count, cough, fibrinogen, hemoglobin, hemoptysis, hypertension, chronic obstructive pulmonary disease (COPD), and chest pain. The RF model outperformed others, achieving an AUC of 0.839 (95% CI 0.780-0.899) and maintaining the highest average performance in external fivefold cross-validation (AUC: 0.906 ± 0.041).

CONCLUSIONS

The RF model demonstrates high and consistent effectiveness in predicting pulmonary embolism risk in tuberculosis patients.

Inflammation modifies the platelet reactivity among thrombocytopenia patients undergoing percutaneous coronary intervention

Percutaneous coronary intervention (PCI) patients combined with thrombocytopenia (TP) are usually considered to be at low ischemic risk, receiving less proper antiplatelet therapy. However, recent studies reported a paradoxical phenomenon that PCI patients with TP were prone to experience thrombotic events, while the mechanisms and future treatment remain unclear. We aim to investigate whether inflammation modifies platelet reactivity among these patients. Consecutive 10 724 patients undergoing PCI in Fuwai Hospital were enrolled throughout 2013. High-sensitivity C-reactive protein (hsCRP) ≥2 mg/L was considered inflammatory status. TP was defined as platelet count <150×109/L. High on-treatment platelet reactivity (HTPR) was defined as adenosine diphosphate-induced platelet maximum amplitude of thromboelastogram >47mm. Among 6617 patients finally included, 879 (13.3%) presented with TP. Multivariate logistic regression demonstrated that patients with TP were associated with a lower risk of HTPR (odds ratio [OR] 0.64, 95% confidence interval [CI] 0.53-0.76) than those without TP in the overall cohort. In further analysis, among hsCRP <2 mg/L group, patients with TP exhibited a decreased risk of HTPR (OR 0.53, 95% CI 0.41-0.68); however, in hsCRP ≥2mg/L group, TP patients had a similar risk of HTPR as those without TP (OR 0.83, 95% CI 0.63-1.08). Additionally, these results remain consistent across subgroups, including patients presenting with acute coronary syndrome and chronic coronary syndrome. Inflammation modified the platelet reactivity of PCI patients with TP, providing new insights into the mechanisms of the increased thrombotic risk. Future management for this special population should pay more attention to inflammation status and timely adjustment of antiplatelet therapy in TP patients with inflammation.

Management of Recurrent Venous Thromboembolism in Severe Immune Thrombocytopenia: A Case Report and a Review of the Literature

We report a case of a 58-year-old man with recurrent unprovoked deep vein thrombosis (DVT) and severe immune thrombocytopenia (ITP) with a platelet count of 19 × 109/L. We further review studies reporting venous thromboembolism (VTE) in patients with severe ITP (≤ 35 × 109/L) and identified 14 patients highlighting VTE risk factors and management of these patients. The present case had several risk factors for VTE (previous DVT, obesity, heterozygosity for factor V Leiden mutation, and previous splenectomy). The patient was initially treated with low-molecular-weight heparin followed by long-term apixaban treatment. The literature review together with our case demonstrates that VTE in severe ITP (≤ 35 × 109/L) can occur in patients with VTE risk factors and antithrombotic management of these patients can be achieved without bleeding depending on severity of thrombocytopenia either by full or reduced dose of anticoagulation together with ITP therapy.

Parvovirus B19 Infection Is Associated with the Formation of Neutrophil Extracellular Traps and Thrombosis: A Possible Linkage of the VP1 Unique Region

Neutrophil extracellular traps (NETs) formation, namely NETosis, is implicated in antiphospholipid syndrome (APS)-related thrombosis in various autoimmune disorders such as systemic lupus erythematosus (SLE) and APS. Human parvovirus B19 (B19V) infection is closely associated with SLE and APS and causes various clinical manifestations such as blood disorders, joint pain, fever, pregnancy complications, and thrombosis. Additionally, B19V may trigger the production of autoantibodies, including those against nuclear and phospholipid components. Thus, exploring the connection between B19V, NETosis, and thrombosis is highly relevant. An in vitro NETosis model using differentiated HL-60 neutrophil-like cells (dHL-60) was employed to investigate the effect of B19V-VP1u IgG on NETs formation. A venous stenosis mouse model was used to test how B19V-VP1u IgG-mediated NETs affect thrombosis in vivo. The NETosis was observed in the dHL-60 cells treated with rabbit anti-B19V-VP1u IgG and was inhibited in the presence of either 8-Br-cAMP or CGS216800 but not GSK484. Significantly elevated reactive oxygen species (ROS), myeloperoxidase (MPO), and citrullinated histone (Cit-H3) levels were detected in the dHL60 treated with phorbol myristate acetate (PMA), human aPLs IgG and rabbit anti-B19V-VP1u IgG, respectively. Accordingly, a significantly larger thrombus was observed in a venous stenosis-induced thrombosis mouse model treated with PMA, human aPLs IgG, rabbit anti-B19V-VP1u IgG, and human anti-B19V-VP1u IgG, respectively, along with significantly increased amounts of Cit-H3-, MPO- and CRAMP-positive infiltrated neutrophils in the thrombin sections. This research highlights that anti-B19V-VP1u antibodies may enhance the formation of NETosis and thrombosis and implies that managing and treating B19V infection could lower the risk of thrombosis.

Classic Light Transmission Platelet Aggregometry: Do We Still Need it?

For more than 50 years, light transmission aggregometry has been accepted as the gold standard test for diagnosing inherited platelet disorders in platelet-rich plasma, although there are other functional approaches performed in whole blood. In this article, several advantages and disadvantages of this technique over other laboratory approaches are discussed in the view of recent guidelines, and the necessity of functional assays, such as light transmission aggregometry in the era of molecular genetic testing, is highlighted.

Addressing thrombosis concerns in immune thrombocytopenia: the role of fostamatinib in immune thrombocytopenia management

INTRODUCTION

Immune thrombocytopenia (ITP), a disease that commonly presents with an increased risk of bleeding, can also paradoxically produce an increased risk of thromboembolic events. The risk of thromboembolism can be associated with patient-related factors (e.g. co-morbidities, age and history of thrombosis), disease-related factors (e.g. a greater proportion of younger, more reactive platelets, and the presence of microparticles and pro-inflammatory cytokines) and treatment-related factors (e.g. splenectomy, thrombopoietin receptor agonists, and IVIg).

AREAS COVERED

Aspects of the pathophysiology of ITP and the effects of treatment are discussed with emphasis on individualizing treatment based on the patient's thromboembolic risk, treatment options and preferences.

EXPERT OPINION

An increased understanding of the pathophysiology of ITP has led to the development of new agents such as fostamatinib, a spleen tyrosine kinase inhibitor. Further research into the factors contributing to the risks for bleeding and thromboembolic events can contribute to the development of more specific therapies for ITP and allow greater individualization of therapy based on each patient's medical history and clinical status.

Recent Strategies and Future Recommendations for the Fabrication of Antimicrobial, Antibiofilm, and Antibiofouling Biomaterials

Biomaterials and biomedical devices induced life-threatening bacterial infections and other biological adverse effects such as thrombosis and fibrosis have posed a significant threat to global healthcare. Bacterial infections and adverse biological effects are often caused by the formation of microbial biofilms and the adherence of various biomacromolecules, such as platelets, proteins, fibroblasts, and immune cells, to the surfaces of biomaterials and biomedical devices. Due to the programmed interconnected networking of bacteria in microbial biofilms, they are challenging to treat and can withstand several doses of antibiotics. Additionally, antibiotics can kill bacteria but do not prevent the adsorption of biomacromolecules from physiological fluids or implanting sites, which generates a conditioning layer that promotes bacteria's reattachment, development, and eventual biofilm formation. In these viewpoints, we highlighted the magnitude of biomaterials and biomedical device-induced infections, the role of biofilm formation, and biomacromolecule adhesion in human pathogenesis. We then discussed the solutions practiced in healthcare systems for curing biomaterials and biomedical device-induced infections and their limitations. Moreover, this review comprehensively elaborated on the recent advances in designing and fabricating biomaterials and biomedical devices with these three properties: antibacterial (bacterial killing), antibiofilm (biofilm inhibition/prevention), and antibiofouling (biofouling inhibition/prevention) against microbial species and against the adhesion of other biomacromolecules. Besides we also recommended potential directions for further investigations.

Apixaban for treatment of venous thromboembolism in an obese patient with Glanzmann thrombasthenia

Background

Glanzmann thrombasthenia (GT) is a rare congenital platelet function disorder associated with a severe bleeding diathesis. Thrombotic manifestations remain a rare condition. We report here the first case of recurrent venous thromboembolism (VTE) successfully treated with apixaban in a patient with GT. Our patient's morbid obesity was an additional challenge.

Key Clinical Question

The Key Clinical Question was to determine if direct oral anticoagulants are suitable for patients with both obesity and GT.

Clinical Approach

In our patient, the first episode of VTE occurred after the use of a low dose of activated recombinant factor VII for a minor procedure, whereas the second was unprovoked. Administration of rivaroxaban very quickly led to the appearance of bleeding symptoms and subsequently led to poor compliance and extension of deep vein thrombosis. The patient was switched to apixaban, with very good efficacy and safety over the cumulative 18 months of use.

Conclusion

The last updated guidelines now recommend the use of rivaroxaban and apixaban for management of VTE in patients with obesity. Regarding patients with GT, there is still insufficient data on the use of direct oral anticoagulants. Management of thrombotic manifestations in these patients remains a rare and complex condition and could be improved by the creation of a specific international registry.

Immune Thrombocytopenic Purpura as a Hemorrhagic Versus Thrombotic Disease: An Updated Insight into Pathophysiological Mechanisms

Immune thrombocytopenic purpura (ITP) is a blood disorder characterized by a low platelet count of (less than 100 × 109/L). ITP is an organ-specific autoimmune disease in which the platelets and their precursors become targets of a dysfunctional immune system. This interaction leads to a decrease in platelet number and, subsequently, to a bleeding disorder that can become clinically significant with hemorrhages in skin, on the mucous membrane, or even intracranial hemorrhagic events. If ITP was initially considered a hemorrhagic disease, more recent studies suggest that ITP has an increased risk of thrombosis. In this review, we provide current insights into the primary ITP physiopathology and their consequences, with special consideration on hemorrhagic and thrombotic events. The autoimmune response in ITP involves both the innate and adaptive immune systems, comprising both humoral and cell-mediated immune responses. Thrombosis in ITP is related to the pathophysiology of the disease (young hyperactive platelets, platelets microparticles, rebalanced hemostasis, complement activation, endothelial activation, antiphospholipid antibodies, and inhibition of natural anticoagulants), ITP treatment, and other comorbidities that altogether contribute to the occurrence of thrombosis. Physicians need to be vigilant in the early diagnosis of thrombotic events and then institute proper treatment (antiaggregant, anticoagulant) along with ITP-targeted therapy. In this review, we provide current insights into the primary ITP physiopathology and their consequences, with special consideration on hemorrhagic and thrombotic events. The accumulated evidence has identified multiple pathophysiological mechanisms with specific genetic predispositions, particularly associated with environmental conditions.

COVID-19-A Trigger Factor for Severe Immune-Mediated Thrombocytopenia in Active Rheumatoid Arthritis

Thrombocytopenia is defined as a platelet count below 150,000/mm³ for adults. There is still controversy about whether individuals with platelet counts of 100,000/mm³ to 150,000/mm³ should be classified as having genuine thrombocytopenia or borderline thrombocytopenia. Thrombocytopenia is considered mild when the platelet count is between 70,000 and 150,000/mm³ and severe if the count is less than 20,000/mm³. Thrombocytopenia in rheumatoid arthritis is a rare complication, with an incidence estimated between 3 and 10%. The main etiological aspects include drug-induced thrombocytopenia and immune thrombocytopenic purpura. The most common hematological abnormalities in SARS-CoV-2 infection are lymphopenia and thrombocytopenia. It has been observed that the severity of thrombocytopenia correlates with the severity of the infection, being a poor prognosis indicator and a risk factor for mortality. COVID-19 can stimulate the immune system to destroy platelets by increasing the production of autoantibodies and immune complexes. Autoimmunity induced by viral infections can be related to molecular mimicry, cryptic antigen expression and also spreading of the epitope. During the COVID-19 pandemic, it is of great importance to include the SARS-CoV-2 infection in differential diagnoses, due to the increased variability in forms of presentation of this pathology. In this review, our aim is to present one of the most recently discovered causes of thrombocytopenia, which is the SARS-CoV-2 infection and the therapeutic challenges it poses in association with an autoimmune disease such as rheumatoid arthritis.