Biomedical application of TiO2NPs can cause arterial thrombotic risks through triggering procoagulant activity, activation and aggregation of platelets.

BACKGROUND: Titanium dioxide nanoparticles (TiO2NPs) are widely used in medical application. However, the relevant health risk has not been completely assessed, the potential of inducing arterial thrombosis (AT) in particular. METHODS: Alterations in platelet function and susceptibility to arterial thrombosis induced by TiO2NPs were examined using peripheral blood samples from healthy adult males and an in vivo mouse model, respectively. RESULTS: Here, using human platelets (hPLTs) freshly isolated from health volunteers, we demonstrated TiO2NP treatment triggered the procoagulant activity of hPLTs through phosphatidylserine exposure and microvesicles generation. In addition, TiO2NP treatment increased the levels of glycoprotein IIb/IIIa and P-selectin leading to aggregation and activation of hPLTs, which were exacerbated by providing physiology-mimicking conditions, including introduction of thrombin, collagen, and high shear stress. Interestingly, intracellular calcium levels in hPLTs were increased upon TiO2NP treatment, which were crucial in TiO2NP-induced hPLT procoagulant activity, activation and aggregation. Moreover, using mice in vivo models, we further confirmed that TiO2NP treatment a reduction in mouse platelet (mPLT) counts, disrupted blood flow, and exacerbated carotid arterial thrombosis with enhanced deposition of mPLT. CONCLUSIONS: Together, our study provides evidence for an ignored health risk caused by TiO2NPs, specifically TiO2NP treatment augments procoagulant activity, activation and aggregation of PLTs via calcium-dependent mechanism and thus increases the risk of AT.

The Buerger's rabbit model: a closer step to unravelling thromboangiitis obliterans?

OBJECTIVE: Thromboangiitis obliterans (TAO) remains clinical challenging due to its rarity and underwhelming management outcomes. This study aimed to describe a novel TAO rabbit model that demonstrates a closer resemblance to TAO. METHODS: Thirty-six New Zealand rabbits underwent the surgical implantation of calibrated gelatin sponge particles (CGSPs) into their right femoral artery. The CGSPs were soaked in different solutions to simulate different types of thrombi: normal (NT; normal saline); inflammatory TAO thrombus (TAO; dimethylsulfoxide [DMSO]), and DMSO with methotrexate (MTX). All groups underwent clinical assessment, digital subtraction angiography (DSA) and histopathological analysis at time points day 0 (immediate), week 1 (acute), week 2 (subacute), and week 4 (chronic). RESULTS: The TAO rabbit presented with signs of ischemia of the right digit at week 4. On DSA, the TAO rabbits exhibited formation of corkscrew collaterals starting week 1. On H&E staining, gradual CGSP degradation was observed along with increased red blood cell aggregation and inflammatory cells migration in week 1. On week 2, disorganization of the tunica media layer and vascular smooth muscle cell (VSMC) proliferation was observed. In the TAO rabbit, migrated VSMCs, inflammatory cells, and extracellular matrix with collagen-like substances gradually occluded the lumen. On week 4, the arterial lumen of the TAO rabbit was filled with relatively-organized VSMC and endothelial cell clusters with less inflammatory cells. Neorevascularization was found in the MTX-treated group. CONCLUSION: The novel TAO rabbit model shows a closer resemblance to human TAO clinically, radiographically, and histopathologically. Histological analysis of the IT progression in the TAO model suggests that it is of VSMC origin.

Effect of Ultrasound on Thrombus debris during Sonothrombolysis in a Microfluidic device.

Microbubble-mediated sonothrombolysis has been proven to be a non-invasive and efficient method for thrombolysis. Nevertheless, there is a potential risk that the thrombus debris generated during the dissolution of the original thrombus are too large and can lead to hazardous emboli. Using a sonothrombolysis microfluidic platform, we investigated the effects of ultrasound power, thrombolytic agent and microbubble concentration on the size of thrombus debris with the example of microbubble-mediated sonothrombolysis of arterial thrombus. Additionally, we studied the effects of ultrasound power on the size and shape of thrombus debris produced by acute and chronic arterial sonothrombolysis. In acute arterial sonothrombolysis, ultrasound power has significant effect on the size of thrombus debris and steadily increases with the increase of ultrasound power. Conversely, in chronic arterial sonothrombolysis, the size of thrombus debris is minimally affected by ultrasound power. Using the sonothrombolysis microfluidic platform, the relationship between ultrasound power and the safety of sonothrombolysis has been illustrated, and the sonothrombolysis microfluidic platform is demonstrated to be a promising tool for further studies on the process of sonothrombolysis.

Overall haemostatic potential assay for prediction of outcomes in venous and arterial thrombosis and thrombo-inflammatory diseases.

Thromboembolic diseases including arterial and venous thrombosis are common causes of morbidity and mortality globally. Thrombosis frequently recurs and can also complicate many inflammatory conditions through the process of 'thrombo-inflammation,' as evidenced during the COVID-19 pandemic. Current candidate biomarkers for thrombosis prediction, such as D-dimer, have poor predictive efficacy. This limits our capacity to tailor anticoagulation duration individually and may expose lower risk individuals to undue bleeding risk. Global coagulation assays, such as the Overall Haemostatic Potential (OHP) assay, that investigate fibrin generation and fibrinolysis, may provide a more accurate and functional assessment of hypercoagulability. We present a review of fibrin's critical role as a central modulator of thrombotic risk. The results of our studies demonstrating the OHP assay as a predictive biomarker in venous thromboembolism, chronic renal disease, diabetes mellitus, post-thrombotic syndrome, and COVID-19 are discussed. As a comprehensive and global measurement of fibrin generation and fibrinolytic capacity, the OHP assay may be a valuable addition to future multi-modal predictive tools in thrombosis.

Recent advances in microfluidic technology of arterial thrombosis investigations.

Microfluidic technology has emerged as a powerful tool in studying arterial thrombosis, allowing researchers to construct artificial blood vessels and replicate the hemodynamics of blood flow. This technology has led to significant advancements in understanding thrombosis and platelet adhesion and aggregation. Microfluidic models have various types and functions, and by studying the fabrication methods and working principles of microfluidic chips, applicable methods can be selected according to specific needs. The rapid development of microfluidic integrated system and modular microfluidic system makes arterial thrombosis research more diversified and automated, but its standardization still needs to be solved urgently. One key advantage of microfluidic technology is the ability to precisely control fluid flow in microchannels and to analyze platelet behavior under different shear forces and flow rates. This allows researchers to study the physiological and pathological processes of blood flow, shedding light on the underlying mechanisms of arterial thrombosis. In conclusion, microfluidic technology has revolutionized the study of arterial thrombosis by enabling the construction of artificial blood vessels and accurately reproducing hemodynamics. In the future, microfluidics will place greater emphasis on versatility and automation, holding great promise for advancing antithrombotic therapeutic and prophylactic measures.

What is the context? To study the mechanism of arterial thrombosis, including the platelet adhesion and aggregation behavior and the coagulation process.Microfluidic technology is commonly used to study thrombosis. Microfluidic technology can simulate the real physiological environment on the microscopic scale in vitro, with high throughput, low cost, and fast speed.As an innovative experimental platform, microfluidic technology has made remarkable progress and has found applications in the fields of biology and medicine.What is new? This review summarizes the different fabrication methods of microfluidics and compares the advantages and disadvantages of these methods. Recent developments in microfluidic integrated systems and modular microfluidic systems have led to more diversified and automated microfluidic chips in the future.The different types and functions of microfluidic models are summarized. Platelet adhesion aggregation and coagulation processes, as well as arterial thrombus-related shear force changes and mechanical behaviors, were investigated by constructing artificial blood vessels and reproducing hemodynamics.Microfluidics can provide a basis for the development of personalized thrombosis treatment strategies. By analyzing the mechanism of action of existing drugs, using microfluidic technology for high-throughput screening of drugs and evaluating drug efficacy, more drug therapy possibilities can be developed.What is the impact?This review utilizes microfluidics to further advance the study of arterial thrombosis, and microfluidics is also expected to play a greater role in the biomedical field in the future.

Direct Oral Anticoagulants in Antiphospholipid Syndrome-Associated Venous Thromboembolism: Real World Evidence.

BACKGROUND: The efficacy and safety of direct oral anticoagulants (DOACs) versus warfarin in patients with antiphospholipid syndrome-associated venous thromboembolism (APS-VTE) remain uncertain. We aimed to evaluate efficacy and safety of DOACs in patients with APS-VTE. METHODS: Using the Korean Health Insurance Review and Assessment Service database, we retrospectively identified all APS-VTE cases. We examined the VTE recurrence, arterial thrombosis, death and bleeding in patients who received DOACs compared with warfarin for therapeutic anticoagulation. RESULTS: Of all the VTE cases (n = 84,916) detected between 2014 and 2018, patients with APS-VTE (n = 410) accounted for 0.48%. Most patients with APS-VTE (73%) were aged < 60 years. The recurrent VTE occurred in 8 of 209 patients (3.8%) who received DOACs and in 7 of 201 (3.5%) who received warfarin (relative risk [RR], 1.099; 95% confidence interval [CI], 0.41-2.98; P = 1.000). The arterial thrombosis (ATE) occurred in 8 of 209 patients (3.8%) who received DOAC and in 20 of 201 (10%) who received warfarin (RR, 0.385; 95% CI, 0.17-0.85; P = 0.024). The composite outcomes of VTE recurrence, ATE, or mortality were significantly lower in patients (9.1%) on DOAC than in those (16.3%) on warfarin (RR, 0.537; 95% CI, 0.32-0.91; P = 0.028). The bleeding outcome occurred in 7 of 209 (3.4%) patients in the DOACs group and 7 of 201 (3.5%) patients in the warfarin group (RR, 0.96; 95% CI, 0.34-2.69; P = 0.840). CONCLUSION: In patients with APS-VTE, DOACs group showed comparable rates of recurrent VTE, bleeding, and deaths, but a significantly lower incidence of ATE and composite outcomes compared with the warfarin group in Korea.

JCAD promotes arterial thrombosis through PI3K/Akt modulation: a translational study.

AIMS: Variants of the junctional cadherin 5 associated (JCAD) locus associate with acute coronary syndromes. JCAD promotes experimental atherosclerosis through the large tumor suppressor kinase 2 (LATS2)/Hippo pathway. This study investigates the role of JCAD in arterial thrombosis. METHODS AND RESULTS: JCAD knockout (Jcad-/-) mice underwent photochemically induced endothelial injury to trigger arterial thrombosis. Primary human aortic endothelial cells (HAECs) treated with JCAD small interfering RNA (siJCAD), LATS2 small interfering RNA (siLATS2) or control siRNA (siSCR) were employed for in vitro assays. Plasma JCAD was measured in patients with chronic coronary syndrome or ST-elevation myocardial infarction (STEMI). Jcad-/- mice displayed reduced thrombogenicity as reflected by delayed time to carotid occlusion. Mechanisms include reduced activation of the coagulation cascade [reduced tissue factor (TF) expression and activity] and increased fibrinolysis [higher thrombus embolization episodes and D-dimer levels, reduced vascular plasminogen activator inhibitor (PAI)-1 expression]. In vitro, JCAD silencing inhibited TF and PAI-1 expression in HAECs. JCAD-silenced HAECs (siJCAD) displayed increased levels of LATS2 kinase. Yet, double JCAD and LATS2 silencing did not restore the control phenotype. si-JCAD HAECs showed increased levels of phosphoinositide 3-kinases (PI3K)/ proteinkinase B (Akt) activation, known to downregulate procoagulant expression. The PI3K/Akt pathway inhibitor-wortmannin-prevented the effect of JCAD silencing on TF and PAI-1, indicating a causative role. Also, co-immunoprecipitation unveiled a direct interaction between JCAD and Akt. Confirming in vitro findings, PI3K/Akt and P-yes-associated protein levels were higher in Jcad-/- animals. Lastly, as compared with chronic coronary syndrome, STEMI patients showed higher plasma JCAD, which notably correlated positively with both TF and PAI-1 levels. CONCLUSIONS: JCAD promotes arterial thrombosis by modulating coagulation and fibrinolysis. Herein, reported translational data suggest JCAD as a potential therapeutic target for atherothrombosis.

The Etiology of the Thrombotic Phenomena Involved in the Process of Coronary Artery Disease-What Is the Role of Thrombophilic Genes in the Development of This Pathology?

Cardiovascular diseases, among which includes coronary artery disease, represent one of the most important causes of mortality and morbidity worldwide. Research aimed at determining the risk factors involved recognizes a group of "traditional" risk factors, but also more recent studies identified over 100 "novel" ones which may have a role in the disease. Among the latter is the thrombophilia profile of a patient, a pathology well-established for its involvement in venous thromboembolism, but with less studied implications in arterial thrombosis. This paper reviews the literature, explaining the pathophysiology of the thrombophilia causes associated most with coronary thrombosis events. Results of several studies on the subject, including a meta-analysis with over 60,000 subjects, determined the significant involvement of factor V Leiden, prothrombin G20210A mutation, plasminogen activator inhibitor-1 and antiphospholipid syndrome in the development of coronary artery disease. The mechanisms involved are currently at different stages of research, with some already established and used as therapeutic targets.

Incidence, Predictors, and Outcomes of Venous and Arterial Thrombosis in COVID-19: A Nationwide Inpatient Analysis.

BACKGROUND: Coronavirus disease 2019 (COVID-19) is known to increase the risk of venous thromboembolism (VTE) and arterial thromboembolism (ATE). However, the incidence, predictors, and outcomes of clinical thrombosis for inpatients with COVID-19 are not well known. This study aimed to enhance our understanding of clinical thrombosis in COVID-19, its associated factors, and mortality outcomes. METHOD: Hospitalised adult (≥18 years of age) patients with COVID-19 in 2020 were retrospectively identified from the US National Inpatient Sample database. Clinical characteristics, incident VTE, ATE, and in-hospital mortality outcomes were recorded. Multivariable logistic regression was performed to identify clinical factors associated with thrombosis and in-hospital mortality in COVID-19 inpatients. RESULTS: A total of 1,583,135 adult patients with COVID-19 in the year 2020 were identified from the National Inpatient Sample database; patients with thrombosis were 41% females with a mean age of 65.4 (65.1-65.6) years. The incidence of thrombosis was 6.1% (97,185), including VTE at 4.8% (76,125), ATE at 3.0% (47,790), and the in-hospital mortality rate was 13.4% (212,785). Patients with thrombosis were more likely to have respiratory symptoms of COVID-19 (76.7% vs 75%, p<0.001) compared with patients without thrombosis. The main factors associated with overall thrombosis, VTE, and ATE were paralysis, ventilation, solid tumours without metastasis, metastatic cancer, and acute liver failure. Although all thrombosis categories were associated with higher in-hospital mortality for COVID-19 inpatients in univariable analyses (p<0.001), they were not in multivariable analyses-thrombosis (odds ratio [OR] 1.24; 95% confidence interval [CI] 0.90-1.70; p=0.19), VTE (OR 0.70; 95% CI 0.52-1.00; p=0.05), and ATE (OR 1.07; 95% CI 0.92-1.25; p=0.36). CONCLUSIONS: The association of COVID-19 with thrombosis and VTE increases with increasing severity of the COVID-19 disease. Risk stratification of thrombosis is crucial in COVID-19 patients to determine the necessity of thromboprophylaxis.

Reports on vascular catheter-associated thromboembolic events in a burn unit - a gap in the literature?

Indwelling intravascular catheters are important tools in the care of critically ill patients; however, they have an inherent risk of infection or thromboembolic events. Reports on catheter associated thromboembolic events in burn units are rare, despite being well recognized that burn patients bear an increased baseline risk for thromboembolic events. We describe two catheter-associated thromboembolic complications in burn patients in a burn unit and the morbidity associated with these events. Patients with endovascular catheters in burn units may be at increased risk for severe thromboembolic events associated with intravascular catheters, but specific guidelines for prevention and management of these patients are still missing.

Antiplatelet and Antithrombotic Properties of Compound L-36, a 6H-1,3,4-Thiadiazine Derivative.

Compound L-36, a new derivative of 6H-1,3,4-thiadiazine, was studied in in vitro and in vivo experiments. This compound exhibits high antiplatelet and antithrombogenic activity. In in vitro experiments, compound L-36 by its antiplatelet activity (by IC50) was superior to acetylsalicylic acid by 9.4 times. In in vivo experiments, compound L-36 by its ED50 value was close to the comparison drug. On the model of pulmonary artery thrombosis, compound L-36 ensured better survival of experimental animals than acetylsalicylic acid. Morphological studies showed that compound L-36 effectively attenuated the thrombosis processes in the pulmonary tissue induced by intravenous injection of a thrombogenic mixture (epinephrine and collagen).

Endothelial SIRT6 deficiency promotes arterial thrombosis in mice.

OBJECTIVE: Arterial thrombosis may be initiated by endothelial inflammation or denudation, activation of blood-borne elements or the coagulation system. Tissue factor (TF), a central trigger of the coagulation cascade, is regulated by the pro-inflammatory NF-κB-dependent pathways. Sirtuin 6 (SIRT6) is a nuclear member of the sirtuin family of NAD+-dependent deacetylases and is known to inhibit NF-κB signaling. Its constitutive deletion in mice shows early lethality with hypoglycemia and accelerated aging. Of note, the role of SIRT6 in arterial thrombosis remains unknown. Thus, we hypothesized that endothelial SIRT6 protects from arterial thrombosis by modulating inhibition of NF-κB-associated pathways. APPROACH AND RESULTS: Using a laser-induced carotid thrombosis model, in vivo arterial occlusion occurred 45% faster in 12-week-old male endothelial-specific Sirt6-/- mice as compared to Sirt6fl/fl controls (n ≥ 9 per group; p = 0.0012). Levels of procoagulant TF were increased in animals lacking endothelial SIRT6 as compared to control littermates. Similarly, in cultured human aortic endothelial cells, SIRT6 knockdown increased TF mRNA, protein and activity. Moreover, SIRT6 knockdown increased mRNA levels of NF-κB-associated genes tumor necrosis factor alpha (TNF-α), poly [ADP-ribose] polymerase 1 (PARP-1), vascular cell adhesion molecule 1 (VCAM-1), and cyclooxygenase-2 (COX-2); at the protein level, COX-2, VCAM-1, TNF-α, and cleaved PARP-1 remained increased after Sirt6 knockdown. CONCLUSIONS: Endothelium-specific Sirt6 deletion promotes arterial thrombosis in mice. In cultured human aortic endothelial cells, SIRT6 silencing enhances TF expression and activates pro-inflammatory pathways including TNF-α, cleaved PARP-1, VCAM-1 and COX-2. Hence, endogenous endothelial SIRT6 exerts a protective role in experimental arterial thrombosis.

Venous and arterial thromboembolic risk of Janus kinase inhibitors: a systematic review with meta-analysis.

OBJECTIVE: Preliminary data led licencing authorities to alert clinicians of an increased venous thrombotic risk associated to the use of Janus kinase (JAK) inhibitors (JAKi). We performed a systematic review to estimate the risk of venous and arterial thrombosis associated to JAKi for the treatment of immune-mediated inflammatory diseases (IMIDs). METHODS: Randomized controlled trials (RCTs) on JAKi in patients with IMIDs were identified by the MEDLINE and EMBASE databases until October 2021. Risk of bias was assessed according to Cochrane criteria. The beta-binomial model was applied to calculate pooled odds ratio (OR) and corresponding 95% CI. The PROSPERO registration number is CRD42022324143. RESULTS: We have included one phase I, 21 phase II, three phase II-III and 36 phase III RCTs for a total of 19 443 patients in the JAKi group and 6354 in the control group. Thirty-one (unweighted rate 0.16%; 95% CI: 0.10, 0.21) events were reported in the JAKi group and 20 (unweighted rate 0.22%; 95% CI: 0.12, 0.32) in the control group in a mean follow-up of 16.8 weeks. IMID patients treated with JAKi did not have an increased thromboembolic risk compared with those treated with placebo (OR 0.82; 95% CI: 0.43, 1.56). No statistically different results were seen in subanalyses for each investigated IMID, drug and dosage. CONCLUSION: JAKi do not increase thromboembolic risk compared with placebo in IMID patients enrolled in selected RCTs.

The mechanism of oleic acid inhibiting platelet activation stimulated by collagen.

BACKGROUND: Abnormal platelet activation is a key factor in the occurrence and development of thrombotic diseases. However, the physiological mechanisms that underlie platelet homeostasis remain unclear. Oleic acid, one of the most abundant lipids in the human diet, has potential antithrombotic effects. This study aimed to investigate the effects of oleic acid on platelet activation and thrombosis. METHODS: Platelet aggregation, ATP release, and fibrinogen spread were evaluated to determine the role of oleic acid in platelet activation. A ferric chloride-induced carotid injury model was used to establish the effect of oleic acid on thrombus formation in vivo. Western blotting analysis and transfection experiments were performed to determine the mechanisms involved in this process. RESULTS: Oleic acid inhibited platelet aggregation, granule release, and calcium mobilization. Furthermore, it inhibited the spread of platelets on fibrinogen. We also found that oleic acid delayed arterial thrombosis in mice, as demonstrated in a murine model of ferric chloride-induced carotid artery thrombosis. The molecular mechanism of its inhibition of platelet activity may be through the Syk-PLCγ2 and CaMKKß/AMPKα/VASP pathways. In addition, we demonstrated that the phosphorylation of AMPK at Ser496 was an important mechanism of platelet activation. CONCLUSIONS: Our study showed that oleic acid inhibits platelet activation and reduces thrombogenesis by inhibiting the phosphorylation of multiple signaling molecules, offering new insights into the research and development of antiplatelet drugs. Video Abstract.

Primary antiphospholipid syndrome with and without limb ischemia: A retrospective observational study.

OBJECTIVE: To compare clinical and laboratory data obtained from patients with primary Antiphospholipid Syndrome (PAPS) with and without limb ischemia (LI). METHODS: A transverse study with 66 (83.3% female) PAPS patients was performed. All data were evaluated. Patients were subdivided into one of two groups: PAPS with LI and PAPS without LI and compared. RESULTS: Sixty-six primary APS were selected. PAPS with LI group exhibited a longer disease duration (p = .012) and more arterial events (p = .002). A lower frequency of venous events was observed in PAPS with LI (p = .007), and deep venous thrombosis (p = .016). Furthermore, PAPS with LI patients had more deficiency of protein C of coagulation (p = .015) than the others. CONCLUSION: PAPS and LI have a distinct clinical and laboratory spectra from those without LI and it is characterized by an increased frequency of protein C deficiency, and a lower frequency of venous events, deep venous thrombosis and IgM anticardiolipin.

Antiphospholipid Syndrome: State of the Art of Clinical Management.

Antiphospholipid syndrome (APS) is a systemic autoimmune disorder clinically characterized by recurrent arterial and venous thrombosis and/or pregnancy morbidity in the presence of antiphospholipid antibodies. Currently, treatment is mainly focused on anticoagulation, but therapies targeting mechanisms involved in APS autoimmune pathogenesis could play an important role in specific settings. An evidence-based therapeutic approach is limited by the broad clinical spectrum of the syndrome and the nature of a "rare disease" that makes it difficult to carry out well-designed prospective studies. Vitamin K antagonists (AVK), notably warfarin, are the standard treatment for preventing recurrent venous thrombosis and perhaps also arterial thrombosis. Direct oral anticoagulants (DOACs) are not recommended at least in patients with triple positivity APS. Treatment options for the prevention of pregnancy complications in obstetric APS, as combined use of aspirin and heparin, low-dose prednisolone, hydroxychloroquine, intravenous immunoglobulin (IVIG), may improve pregnancy outcome. The catastrophic antiphospholipid syndrome (CAPS) is the most severe form of APS with acute multiple organ involvement and small vessel thrombosis. Glucocorticoids, heparin, plasma exchange or IVIG, rituximab, or eculizumab must be added to concurrent treatment of precipitating factors (e.g. infections) as rescue therapies. Finally, it has been observed that SARS COV2 infection may produce vascular complications mimicking the clinical and pathophysiological features of APS and particularly of CAPS. From this point of view, attention has been focused on the "protective" role of anticoagulant therapy in preventing thrombotic complication when these clinical conditions coexist.

Thrombosis in Acute Myeloid Leukemia: Pathogenesis, Risk Factors and Therapeutic Challenges.

OPINION STATEMENT: Prophylaxis and treatment of thrombosis in leukemic patients still represent a major challenge with several clinical questions yet to be solved. Indeed, the paucity of evidence makes the management of venous thromboembolic events difficult and not uniform. Due to thrombocytopenia, patients with acute myeloid leukemia (AML) are underrepresented in trials investigating prophylaxis and treatment of thrombosis in cancer, and prospective data are lacking. Likewise, the therapeutic approach with anti-coagulants in leukemic patients is inferred from guidelines originally developed in the solid cancer setting and clear recommendations in the thrombocytopenic population are limited. Importantly, the discrimination of patients at high risk of bleeding from those with a predominant risk of thrombosis remains extremely difficult with no predictive score validated so far. Thus, the management of thrombosis often relies on clinician experience, and it is tailored to the individual patient, constantly balancing thrombotic and hemorrhagic risks. Who would benefit from primary prophylaxis and how a thrombotic event should be appropriately treated are some of the unanswered questions that the future guidelines and trials should address. Moreover, a greater effort should be made to identify robust predictive factors able to guide clinicians in the management of this potential serious complication for AML patients.

A 12-year nationwide cohort study on the association between central retinal artery occlusion and cancer.

PURPOSE: This study aims to investigate the association between incident central retinal artery occlusion (CRAO) and the subsequent development of cancer. METHODS: We included incident CRAO patients from the 2002-2013 National Health Insurance Service database in South Korea. For the patient cohort, we included patients diagnosed with CRAO from the database, and excluded patients having CRAO or any cancer history during the first 2-year washout period (2002-2003). Then, we defined their 1:4 propensity-score matched non-CRAO subjects as controls, all of whom also had no history of cancer during the washout period. Time-varying covariate Cox regression models were conducted to determine the association of CRAO with cancer. Kaplan-Meier curves with log-rank test were also analyzed. RESULTS: A total of 9712 patients with CRAO and 38,848 controls were included in the study. CRAO was associated with an increased risk of subsequent cancer (hazard ratio = 1.27; 95% confidence interval, 1.19-1.35). The incidence rate of overall cancer during the study period was 29.12 per 1000 person-years in the CRAO group and 22.77 per 1000 person-years in the control group. Incidence probability of overall cancer was significantly higher among CRAO patients than controls (P < 0.001, log-rank test). CONCLUSION: The risk of cancer occurrence was increased in patients with CRAO. The results supported that CRAO could be attributed to one of the consequences of arterial thrombosis in cancer patients.

Remdesivir use in severe and critical COVID-19 patients might be associated with lower incidence of arterial thrombotic events.

INTRODUCTION: Venous thromboembolism (VTE) and arterial thrombotic (AT) events are a striking feature of severe COVID-19, however, relationship of remdesivir use and the risk of thrombotic events is unknown and has not been investigated before. METHODS: We retrospectively analyzed a cohort of 876 consecutive hospitalized severe and critical COVID-19 patients who were treated with remdesivir and compared them to 876 case-matched control patients. All patients were treated in our tertiary-level institution in period from 10/2020 to 6/2021. VTE and AT were diagnosed by objective imaging and laboratory methods. RESULTS: After exclusion of 71 VTE and 37 AT events present at the time of hospital admission, there were a total of 70 VTE (35 in the remdesivir and 35 in the control group) and 38 AT events occurring during hospitalization (13 in the remdesivir and 25 in the control group). There was a similar cumulative post-admission VTE incidence among both remdesivir and matched control patients (P = 0.287). Significantly lower cumulative post-admission AT incidence was observed among patients treated with remdesivir than among matched control patients (1.7% vs 3.3%, HR = 0.51, P = 0.035). Tendency for lower AT rates was evident in subgroups of patients stratified according to the type of AT, as well as according to the intensity of required oxygen supplementation at the time of remdesivir use. CONCLUSION: Remdesivir use in severe and critical COVID-19 patients might be associated with lower occurrence of AT during hospitalization, whereas similar rates of VTE events were observed among both patients treated with remdesivir and control patients.

Acute lower extremity arterial thrombosis associated with nephrotic syndrome in adults: case series and literature review.

BACKGROUND: Nephrotic syndrome (NS) is a condition associated with hypercoagulability. Thromboembolic events are a well-recognized complication of NS. Venous thrombosis is well known, while arterial thrombosis, which is more severe, occurs less frequently and is mainly reported in children in the literature. The aim of this study was to understand these rare adult cases of NS associated with acute lower extremity arterial thrombosis and draw attention to them to prevent misdiagnosis and delayed treatment. METHODS: From January 2011 and October 2022, we conducted a retrospective study of patients with NS and arterial thrombosis. Their clinical manifestations, imaging characteristics, treatments and outcomes were analyzed and compared, and a literature review was performed. RESULTS: Nine adults with NS and acute lower limb arterial thrombosis were described. In seven of these patients, six had fresh thrombi that preceded the NS diagnosis, while one had a history of NS for 14 years and previously underwent an emergency thrombectomy. Three of the seven patients eventually underwent above-knee amputations, and the other four underwent arterial revascularization with satisfactory recovery of lower-extremity perfusion. In addition to the seven patients mentioned above, the other two received successful anticoagulant treatment, as the thrombosis was present only in the popliteal artery. CONCLUSION: Acute lower extremity arterial thrombosis is a rare but serious and potentially lethal complication in patients with NS, and early recognition and appropriate management are crucial for good patient outcomes.