Thrombosis: a major contributor to the global disease burden

Circulating MicroRNAs for Diagnosis of Acute Pulmonary Embolism: Still a Long Way to Go

Venous thromboembolism (VTE) represents the third most frequent cause of acute cardiovascular syndrome. Among VTE, acute pulmonary embolism (APE) is the most life-threatening complication. Due to the low specificity of symptoms clinical diagnosis of APE may be sometimes very difficult. Accordingly, the latest European guidelines only suggest clinical prediction tests for diagnosis of APE, eventually associated with D-dimer, a biomarker burdened by a very low specificity. A growing body of evidence is highlighting the role of miRNAs in hemostasis and thrombosis. Due to their partial inheritance and susceptibility to the environmental factors, miRNAs are increasingly described as active modifiers of the classical Virchow's triad. Clinical evidence on deep venous thrombosis reported specific miRNA signatures associated to thrombosis development, organization, recanalization, and resolution. Conversely, data of miRNA profiling as a predictor/diagnostic marker of APE are still preliminary. Here, we have summarized clinical evidence on the potential role of miRNA in diagnosis of APE. Despite some intriguing insight, miRNA assay is still far from any potential clinical application. Especially, the small sample size of cohorts likely represents the major limitation of published studies, so that extensive analysis of miRNA profiles with a machine learning approach are warranted in the next future. In addition, the cost-benefit ratio of miRNA assay still has a negative impact on their clinical application and routinely test.

Awareness and Perception of Hospitalized Patients on Thromboembolism and Thromboprophylaxis: A Cross-Sectional Study in Sana'a-Yemen

PURPOSE

Patients' awareness toward VTE and thromboprophylaxis is critical for medication adherence. This study aimed to evaluate the patient's awareness and perception towards VTE and its prophylaxis and to assess patient's satisfaction towards the information given by the medical staff.

PARTICIPANTS AND METHODS

A cross-sectional survey was conducted among hospitalized patients who received VTE prophylaxis in public and private hospitals in Sana'a, Yemen. Besides sociodemographic variables, participants' awareness and perception of VTE and its prophylaxis were evaluated. Variables' association with VTE awareness were analyzed using univariable and multivariable logistic regression using SPSS.

RESULTS

A total of 396 of the hospitalized patients agreed to participate in the study, with 31% (n = 121) have ever heard about VTE. The multivariable logistic regression findings revealed that the participants who did not have a profession had OR = 17.182 (P < 0.001) of being unaware of VTE compared with those who had one. Participants who did not have a personal history of VTE had OR = 7.580 (P < 0.001) of being unaware of DVT/PE compared with the participants who had a personal history of VTE. Male participants had OR = 2.839 (P < 0.005) of being unaware of DVT/PE compared with female participants. Participants who were illiterate had OR = 2.832 (P < 0.022) of being unaware of DVT/PE compared with participants with a higher level of education.

CONCLUSION

The study revealed lack of awareness and perception of VTE and its prophylaxis among hospitalized patients in Yemen. The patients who are unaware of the disease have wrong perception about their role in DVT prophylaxis. Patient's education must be considered in healthcare setting to improve patient's health outcomes.

Today's view of hereditary thrombophilia

Venous thromboembolism (VTE) is still a serious medical problem with the non-decreasing incidence of new cases despite prophylaxis in risky situations. It is a multifactorial disease, in which the hereditary component is also significantly involved. The aim of the current research is to search for new polymorphisms that are involved in thrombogenesis in addition to classical thrombophilia (deficiency of natural coagulation inhibitors and FVL and FII prothrombin mutations). The article provides an overview of the results of already performed genome-wide association studies of VTE and their use for the calculation of the so-called polygenic risk score, which could be used for individualized prevention of VTE after standardization of the method.

Endothelial Activation Markers in Polytransfused Children with Beta Thalassemia: Study from a Tertiary Care Centre in India

Beta thalassemia major is associated with a subclinical hypercoagulable state. Endothelial activation markers like soluble Intercellular adhesion molecule (sICAM-1) and E-selectin have been implicated in the pathogenesis of endothelial dysfunction and hemostatic alterations. In this study we aimed to study serum levels of sICAM-1 and E-selectin in polytransfused children with β thalassemia major and their association with serum ferritin and D-dimer levels. Sixty-two polytransfused β-thalassemia major children aged between 5 and 17 years and 26 age and gender matched healthy controls were enrolled in the study. Complete blood count with peripheral smear, liver function tests, serum ferritin, coagulation tests [PT, APTT, D-dimer] and endothelial activation marker tests [ICAM-1 and E-selectin] were performed. PT, APTT and D-dimer levels were significantly higher in beta-thalassemia major patients than in control group (p = 0.003, p < 0.001, p < 0.001 respectively). Mean ICAM-1 and E-selectin levels were 731.34 ± 343.97 ng/ml and 111.75 ± 40.13 ng/ml respectively which were significantly higher than control group (p < 0.001, p < 0.001 respectively). No significant correlation of ICAM-1 and E-selectin was observed with serum ferritin, PT, APTT and D-dimer levels. The findings of the present study suggest that there is ongoing subclinical activation of coagulation cascade and fibrinolytic system in these patients. Endothelial activation markers may be used as early indicators of endothelial dysfunction to assess the thrombotic complications in beta thalassemia.

Rivaroxaban Pharmacokinetics in Obese Subjects: A Systematic Review

INTRODUCTION

Venous thromboembolism (VTE) is a leading cause of morbidity and mortality globally. The direct oral anticoagulants, including rivaroxaban, are relatively novel therapeutic options in the treatment and prevention of VTE. There is a conflicting and inconclusive evidence surrounding the pharmacokinetics (PK) of rivaroxaban in patients with VTE who are obese.

OBJECTIVES

We conducted a systematic review to provide an overview, and to synthesize the available evidence in the current literature pertaining to rivaroxaban PK in obese subjects who are healthy or diseased.

METHODS

The PubMed, Embase, ScienceDirect, Rayyan, and Cochrane Library databases were systematically searched from 1 May 2021 through 28 February 2022. Studies investigating rivaroxaban PK in adult obese subjects were included in the review. Pertinent data, including anthropometric parameters, rivaroxaban dosage regimen, PK parameters, PK model, and outcome measures were extracted. Reference values of rivaroxaban PK parameters in the general population were used for comparison purposes. The review protocol was registered in the PROSPERO database (CRD42020177770).

RESULTS

In the 11 studies included in this systematic review, over 7140 healthy or diseased subjects received rivaroxaban therapy, with varying clinical indications in the diseased population. The reported PK parameters of rivaroxaban in obese subjects compared with reference values in the general population were variable. The reported values of the volume of distribution (V_d) among obese subjects (73.4-82.8 L) fell within the range of values reported/calculated for the general population (59.4-104 L), assuming complete bioavailability. However, some of the reported values of clearance (CL) in obese subjects (7.86-16.8 L.h^-1) do not fall within the range of values reported/calculated for the general population (5.57-11.3 L.h^-1). The reported maximum plasma concentrations in obese subjects versus the general population following a 10 mg dose were 149 vs. 143-180 µg.L^-1, and following a 20 mg dose were 214-305 vs. 299-360 µg.L^-1, respectively. The area under the plasma concentration versus time curves (AUC) over different intervals in obese subjects versus the general population following a 10 mg dose were 1155 (AUC from time zero to infinity [AUC_∞]) vs. 1029 (AUC_∞) µg.h.L^-1; and 1204-2800 (AUC from time zero to 24 h [AUC₂₄]) vs. 3200 (AUC₂₄) µg.h.L^-1, respectively, following a 20 mg dose. The reported values of half-life and time to reach the maximum plasma concentration in obese subjects versus the general population were not consistent across studies.

CONCLUSION

Variable changes and inconsistencies in different rivaroxaban PK parameters were reported in obese subjects. Further well-designed studies are warranted to better characterize the PK and clinical outcomes of rivaroxaban in subjects with obesity.

Internal Validation of a Risk Scoring System for Venous Thromboembolism After Total hip or Knee Arthroplasty

We developed a computerized clinical decision support system (CCDSS) for venous thromboembolism (VTE) risk assessment. We aimed to demonstrate its relevance and evaluate associations between risk level and VTE incidence in patients undergoing total hip/knee arthroplasty. In this case-control study, VTE was confirmed using ultrasonography/computed tomography angiography in 1098 adults at a tertiary care hospital over five years (2013-2018). Postoperative VTE incidence was classified into three risk levels (moderate, high, and highest). The overall VTE incidence was 11.7%, which increased with a risk level of 0%, 5.8%, and 12.8% in moderate-risk, high-risk, and highest-risk patients, respectively. Highest-risk patients were significantly more likely to develop VTE than high-risk patients (odds ratio [OR] 2.4; 95% confidence interval [CI] 1.2-5.5; p = 0.01). VTE development was more likely in patients with risk scores ≥4 relative to those with risk scores of 2-3 (OR 1.8; 95% CI 1.2-2.7; p = 0.003) and -1 to 1 (OR 3.3; 95% CI 1.6-7.7; p < 0.001). This study indicates that risk level and VTE incidence are associated; our scoring system appears useful for patients undergoing total hip/knee arthroplasty.

Crosstalk between Venous Thromboembolism and Periodontal Diseases: A Bioinformatics Analysis

Background

This current study applied bioinformatics analysis to reveal the crosstalk between venous thromboembolism (VTE) and periodontitis, as well as the potential role of immune-related genes in this context.

Methods

Expression data were downloaded from the GEO database. Blood samples from venous thromboembolism (VTE) were used (GSE19151), while for periodontal disease, we used gingival tissue samples (GSE10334, GSE16134, and GSE23586). After batch correction, we used “limma” packages of R language for differential expression analysis (p value < 0.05, ∣logFC | ≥0.5). We used Venn diagrams to extract the differentially expressed genes common to VTE and periodontitis as potential crosstalk genes and applied functional enrichment analysis (GO biological process and KEGG pathway). The protein-protein interaction (PPI) network of crosstalk genes was constructed by Cytoscape software. The immune-related genes were downloaded from the literature. The Wilcoxon test was used to test the scores of immune infiltrating cells. The crosstalk genes were further screened by LASSO Logistic Regression.

Results

For periodontitis, 427 case and 136 control samples, and for VTE, 70 case and 63 control samples were included. The obtained PPI network had 1879 nodes and 2257 edges. Moreover, 782 immune genes and 28 cell types were included in the analysis. Over 90% of immune cells had different expressions in VTE and periodontitis. We obtained 12 significant pathways corresponding to crosstalk genes. CD3D, CSF3R, and CXCR4 acted as an immune gene and a crosstalk gene. We obtained a total of 12 shared biomarker crosstalk genes. Among those 12 biomarker crosstalk genes, 4 were immune genes (LGALS1, LSP1, SAMSN1, and WIPF1).

Conclusion

Four biomarker crosstalk genes between periodontitis and VTE were also immune genes, i.e., LGALS1, LSP1, SAMSN1, and WIPF1. The findings of the current study need further validation and are a basis for development of biomarkers.

Identification of four hub genes in venous thromboembolism via weighted gene coexpression network analysis

Background

The pathogenic mechanisms of venous thromboembolism (VT) remain to be defined. This study aimed to identify differentially expressed genes (DEGs) that could serve as potential therapeutic targets for VT.

Methods

Two human datasets (GSE19151 and GSE48000) were analyzed by the robust rank aggregation method. Gene ontology and Kyoto encyclopedia of genes and genomes pathway enrichment analyses were conducted for the DEGs. To explore potential correlations between gene sets and clinical features and to identify hub genes, we utilized weighted gene coexpression network analysis (WGCNA) to build gene coexpression networks incorporating the DEGs. Then, the levels of the hub genes were analyzed in the GSE datasets. Based on the expression of the hub genes, the possible pathways were explored by gene set enrichment analysis and gene set variation analysis. Finally, the diagnostic value of the hub genes was assessed by receiver operating characteristic (ROC) analysis in the GEO database.

Results

In this study, we identified 54 upregulated and 10 downregulated genes that overlapped between normal and VT samples. After performing WGCNA, the magenta module was the module with the strongest negative correlation with the clinical characteristics. From the key module, FECH, GYPA, RPIA and XK were chosen for further validation. We found that these genes were upregulated in VT samples, and high expression levels were related to recurrent VT. Additionally, the four hub genes might be highly correlated with ribosomal and metabolic pathways. The ROC curves suggested a diagnostic value of the four genes for VT.

Conclusions

These results indicated that FECH, GYPA, RPIA and XK could be used as promising biomarkers for the prognosis and prediction of VT.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-021-02409-4.

Downregulation of microRNA-200c-3p alleviates the aggravation of venous thromboembolism by targeting serpin family C member 1

Venous thromboembolism (VTE) is the third most prevalent cardiovascular complication. Increasing studies have demonstrated that some microRNAs (miRNAs) are aberrantly expressed in VTE and play crucial roles in mediating the development of VTE. Therefore, our study intends to explore the detailed function and molecular mechanism of miR-200c-3p in VTE progression. In our research, VTE rat models were first established via inferior vena cava (IVC) ligation and the time-dependent effects of IVC ligation on thrombus formation were discovered. The results of reverse transcription quantitative polymerase-chain reaction (RT-qPCR) and western blotting showed that serpin family C member 1 (SERPINC1) was downregulated in VTE rat models and showed an inverse correlation with thrombus load. MiRNA target prediction tools and luciferase reporter assay confirmed SERPINC1 as a target for miR-200c-3p. VTE rats were injected with miR-200c-3p inhibitor for 24 h to investigate whether miR-200c-3p knockdown influences thrombus formation in vivo. Histological examination through hematoxylin-eosin staining revealed that miR-200c-3p downregulation markedly inhibited the formation of thrombus in IVC of rats. Additionally, miR-200c-3p was upregulated while SERPINC1 was downregulated in serum and inferior vena cava of VTE rats as well as in plasma of patients with VTE. Linear regression analysis demonstrated that miR-200c-3p expression was negatively correlated to SERPINC1 expression in VTE rats and patients with VTE. Our study determines the previously unelucidated function of miR-200c-3p in VTE, which might provide a potential novel insight for the treatment of VTE.

Improving Venous Thromboembolism Prophylaxis Administration in an Acute Surgical Unit

OBJECTIVES

Venous thromboembolism (VTE) prophylaxis regimes frequently have a wide variation in application. Nepean acute surgical unit was established in 2006 as a novel model for emergency surgical care. As part of the model's rollout, there were several areas of clinical management targeted for improvement, one being VTE prophylaxis compliance. It was decided all patients older than 18 years treated for a variety of acute surgical conditions within the acute surgical unit should be administered routine VTE prophylaxis with heparin and compression stockings. A novel multifaceted intervention was implemented at the time to achieve this goal. The primary aim of this study was to determine VTE prophylaxis administration rates before and after this intervention.

METHODS

A before-after study conducted as a retrospective review of medical records of all patients 18 years or older, having an appendicectomy in 3 periods: Before acute surgical unit (ASU) (November 2004 to October 2006), Early ASU (November 2006 to October 2008), and Established ASU (January 2012 to December 2013). Outcomes were mechanical and pharmacological VTE prophylaxis administration rates for each group.

RESULTS

There were 1149 patients included in the study: Before ASU, 167; Early ASU, 375; and Established ASU, 607. There was a significant stepwise increase in parmacological VTE prophylaxis administration: Before ASU, 54.5%; Early ASU, 74.7%; and Established ASU, 96.9% (Before versus Early: odds ratio [OR], 2.46; 95% confidence interval [CI], 1.68-3.61; P < 0.001; Early versus Established: OR, 10.500; 95% CI, 6.29-17.53; P < 0.001). Mechanical VTE prophylaxis was significantly increased in the established group (Before versus Established: OR, 47.18; 95% CI, 25.61-86.91; P < 0.001).

CONCLUSIONS

There was a significant increase in VTE prophylaxis administration after the implementation of our multifaceted intervention. Allocating a responsible provider dedicated to VTE prophylaxis prescription and compliance checking was a key component to this intervention.

Plasma procoagulant phospholipid clotting time and venous thromboembolism risk

BACKGROUND

Negatively charged procoagulant phospholipids, phosphatidylserine (PS) in particular, are vital to coagulation and expressed on the surface membrane of extracellular vesicles. No previous study has investigated the association between plasma procoagulant phospholipid clotting time (PPLCT) and future risk of venous thromboembolism (VTE).

OBJECTIVES

To investigate the association between plasma PPLCT and the risk of incident VTE in a nested case-control study.

METHODS

We conducted a nested case-control study in 296 VTE patients and 674 age- and sex-matched controls derived from a general population cohort (The Tromsø Study 1994-2007). PPLCT was measured in platelet-free plasma using a modified factor Xa-dependent clotting assay. Logistic regression was used to estimate odds ratio (OR) with 95% confidence intervals (CI) for VTE with PPLCT modelled as a continuous variable across quartiles and in dichotomized analyses.

RESULTS

There was a weak inverse association between plasma PPLCT and risk of VTE per 1 standard deviation increase of PPLCT (OR 0.93, 95% CI 0.80-1.07) and when comparing those with PPLCT in the highest quartile (OR 0.89, 95% CI 0.60-1.30) with those in the lowest quartile. Subjects with PPLCT >95th percentile had substantially lowered OR for VTE (OR 0.35, 95% CI 0.13-0.81). The inverse association was stronger when the analyses were restricted to samples taken shortly before the event. The risk estimates by categories of plasma PPLCT were similar for deep vein thrombosis and pulmonary embolism.

CONCLUSION

Our findings suggest that high plasma PPLCT is associated with reduced risk of VTE.

Proteomics in Thrombosis and Haemostasis

No Abstract.

Effects of statins in primary and secondary prevention for venous thromboembolism events: A meta analysis

OBJECTIVE

The associations between statins use and incidence or recurrence of venous thromboembolism (VTE) are controversial. We aimed to conduct a meta-analysis to reconcile the conflicting results.

METHODS

We searched PubMed, Embase and Cochrane Library for studies published from database inception until May 31, 2021. Cohort studies and Randomized Controlled Trials that reported incidence or recurrence of VTE using statins compared with placebo or non-statins were included for meta-analysis.

RESULTS

A total of 43 studies comprising over 8.6 million participants were included for analysis. The median follow-up duration was 38.1 months. Compared with no statins treatment, statins appeared to have a protective effect in primary prevention of VTE (RR 0.78, 95% CI 0.72-0.85), but significant heterogeneity was found among included studies (I² = 81%). Statins was also associated with a 26% reduced risk of recurrent VTE (RR 0.74, 95% CI 0.70-0.78), even in patients receiving anticoagulant therapy (RR 0.77, 95% CI 0.65-0.92). In patients with a history of VTE, statins was associated with a reduced risk of bleeding and all cause mortality. The NNT of statins to prevent one case of VTE in the cancer population, and one case of recurrent VTE in patients with a history of VTE was 103.1 and 90.7 person-years respectively.

CONCLUSION

In high-risk patients, statins treatment may reduce the incidence of VTE. Statins can also reduce the risk of recurrent VTE and all-cause mortality in patients with a history of VTE.

Gone in 60 days: our first experience with a bioconvertible IVC filter

The Sentry bioconvertible IVC filter (Boston Scientific, MA, USA) contains a bioabsorbable filament which hydrolyses after 60 days, allowing the arms of the filter to spring open, retract into the vessel wall and endothelialise, leaving an unobstructed IVC lumen.

It is a novel treatment option for patients at transient risk of pulmonary emboli with a contraindication to anticoagulation. The device provides similar protection to other currently available devices against pulmonary emboli with minimal complications. It represents an effective alternative to retrievable filters, the removal of which is variously not attempted, not possible or associated with high complication rates.

We review the literature which underpins the development of the bioconvertible filter. We describe our first deployment of the filter in an 85-year-old female with gastric malignancy (who subsequently underwent a subtotal gastrectomy) with a history of anaemia and previous pulmonary emboli. The availability of a bioconvertible filter constitutes a further step forward in the management of patients with potential or active thromboembolic disease.

Advances and Utility of the Human Plasma Proteome

The study of proteins circulating in blood offers tremendous opportunities to diagnose, stratify, or possibly prevent diseases. With recent technological advances and the urgent need to understand the effects of COVID-19, the proteomic analysis of blood-derived serum and plasma has become even more important for studying human biology and pathophysiology. Here we provide views and perspectives about technological developments and possible clinical applications that use mass-spectrometry(MS)- or affinity-based methods. We discuss examples where plasma proteomics contributed valuable insights into SARS-CoV-2 infections, aging, and hemostasis and the opportunities offered by combining proteomics with genetic data. As a contribution to the Human Proteome Organization (HUPO) Human Plasma Proteome Project (HPPP), we present the Human Plasma PeptideAtlas build 2021-07 that comprises 4395 canonical and 1482 additional nonredundant human proteins detected in 240 MS-based experiments. In addition, we report the new Human Extracellular Vesicle PeptideAtlas 2021-06, which comprises five studies and 2757 canonical proteins detected in extracellular vesicles circulating in blood, of which 74% (2047) are in common with the plasma PeptideAtlas. Our overview summarizes the recent advances, impactful applications, and ongoing challenges for translating plasma proteomics into utility for precision medicine.

Inflammatory Bowel Disease and Risk of Major Bleeding During Anticoagulation for Venous Thromboembolism

BACKGROUND

Little is known about the bleeding risk in patients with inflammatory bowel disease (IBD) and venous thromboembolism (VTE) treated with anticoagulation. Our aim was to elucidate the rate of major bleeding (MB) events in a well-defined cohort of patients with IBD during anticoagulation after VTE.

METHODS

This study is a retrospective follow-up analysis of a multicenter cohort study investigating the incidence and recurrence rate of VTE in IBD. Data on MB and IBD- and VTE-related parameters were collected via telephone interview and chart review. The objective of the study was to evaluate the impact of anticoagulation for VTE on the risk of MB by comparing time periods with anticoagulation vs those without anticoagulation. A random-effects Poisson regression model was used.

RESULTS

We included 107 patients (52 women, 40 with ulcerative colitis, 64 with Crohn disease, and 3 with unclassified IBD) in the study. The overall observation time was 388 patient-years with and 1445 patient-years without anticoagulation. In total, 23 MB events were registered in 21 patients, among whom 13 MB events occurred without anticoagulation and 10 occurred with anticoagulation. No fatal bleeding during anticoagulation was registered. The incidence rate for MB events was 2.6/100 patient-years during periods exposed to anticoagulation and 0.9/100 patient-years during the unexposed time. Exposure to anticoagulation (adjusted incidence rate ratio, 3.7; 95% confidence interval, 1.5-9.0; P = 0.003) and ulcerative colitis (adjusted incidence rate ratio, 3.5; 95% confidence interval, 1.5-8.1; P = 0.003) were independent risk factors for MB events.

CONCLUSION

The risk of major but not fatal bleeding is increased in patients with IBD during anticoagulation. Our findings indicate that this risk may be outweighed by the high VTE recurrence rate in patients with IBD.

Evaluating the "holiday season effect" of hospital care on the risk of mortality from pulmonary embolism: a nationwide analysis in Taiwan

We aimed to determine whether hospital admissions during an extended holiday period (Chinese New Year) and weekends were associated with increased mortality risk from pulmonary embolism (PE), compared to admissions on weekdays. We conducted a nationwide retrospective cohort study using Taiwan's National Health Insurance Research Database. Data of newly diagnosed PEs during the months of January and February from 2001 to 2017 were obtained from patient records and classified into three admission groups: Chinese New Year (≥ 4 consecutive holiday days), weekends, and weekdays. The adjusted odds ratios (aORs) (95% confidence intervals [CIs]) for 7-day and in-hospital mortality were calculated using multivariable logistic regression models. The 7-day and in-hospital mortality risks were higher for patients admitted during the Chinese New Year holiday (10.6% and 18.7%) compared to those admitted on weekends (8.4% and 16.1%) and weekdays (6.6% and 13.8%). These higher mortality risks for holiday admissions compared to weekday admissions were confirmed by multivariable analysis (7-day mortality: aOR = 1.68, 95% CI 1.15-2.44, P = 0.007; in-hospital mortality: aOR = 1.41, 95% CI 1.05-1.90, P = 0.022), with no subgroup effects by sex or age. Hospital admission for PE over an extended holiday period, namely Chinese New Year, was associated with an increased risk of mortality.

Low awareness of venous thromboembolism among the general population: a call for increased public enlightenment programs

BACKGROUND

Venous thromboembolism (VTE) is a notable but often ignored cause of disability and death. Improved public awareness of the symptoms and risks associated with VTE reduces the burden of disease.

AIM

We aimed to determine the awareness of VTE among the general population.

METHODS

We conducted a population-based study using a pre-tested, pre-validated Ipsos-Reid questionnaire between October 2019 to March 2020. The questionnaire was distributed to consenting adults in the capital cities of Enugu and Ebonyi states of South-Eastern Nigeria to determine their awareness and knowledge of the symptoms and risk factors of VTE.

RESULTS

A total of 284 adults participated with a mean age of 32.73 ± 10.33 years and majority (70.8%) had a post-secondary education. While majority were aware of other medical conditions like a heart attack (96.1%), stroke (97.2%), diabetes (98.2%), HIV/AIDS (98.6%), cancer (97.2%) and malaria (98.2), just a few of the subjects were aware of thrombosis (41.5%) and DVT (33.8%). Less than half (42.4%) correctly described DVT as a blood clot in the vein and 13.7% of the respondents knew what PE feels like. A minority of them knew the risk factors of VTE included hospital stay (19.0%), surgery (37.2%), cancer (31.6%), pregnancy (31.6%) and old age (29.6%). Age and gender showed no statistically significant association with awareness of VTE, p value, 0.491 and 0.287, respectively.

CONCLUSION

The awareness of VTE in the general population is low. Public awareness programs should be a public health priority to reduce morbidity and mortality associated with VTE.

Non-invasive diagnosis of deep vein thrombosis from ultrasound imaging with machine learning

Deep vein thrombosis (DVT) is a blood clot most commonly found in the leg, which can lead to fatal pulmonary embolism (PE). Compression ultrasound of the legs is the diagnostic gold standard, leading to a definitive diagnosis. However, many patients with possible symptoms are not found to have a DVT, resulting in long referral waiting times for patients and a large clinical burden for specialists. Thus, diagnosis at the point of care by non-specialists is desired. We collect images in a pre-clinical study and investigate a deep learning approach for the automatic interpretation of compression ultrasound images. Our method provides guidance for free-hand ultrasound and aids non-specialists in detecting DVT. We train a deep learning algorithm on ultrasound videos from 255 volunteers and evaluate on a sample size of 53 prospectively enrolled patients from an NHS DVT diagnostic clinic and 30 prospectively enrolled patients from a German DVT clinic. Algorithmic DVT diagnosis performance results in a sensitivity within a 95% CI range of (0.82, 0.94), specificity of (0.70, 0.82), a positive predictive value of (0.65, 0.89), and a negative predictive value of (0.99, 1.00) when compared to the clinical gold standard. To assess the potential benefits of this technology in healthcare we evaluate the entire clinical DVT decision algorithm and provide cost analysis when integrating our approach into diagnostic pathways for DVT. Our approach is estimated to generate a positive net monetary benefit at costs up to £72 to £175 per software-supported examination, assuming a willingness to pay of £20,000/QALY.

Epigallocatechin gallate inhibits release of extracellular vesicles from platelets without inhibiting phosphatidylserine exposure

Arterial thrombosis triggers myocardial infarction and is a leading cause of death worldwide. Procoagulant platelets, a subpopulation of activated platelets that expose phosphatidylserine (PS), promote coagulation and occlusive thrombosis. Procoagulant platelets may therefore be a therapeutic target. PS exposure in procoagulant platelets requires TMEM16F, a phospholipid scramblase. Epigallocatechin gallate (EGCG) has been reported to inhibit TMEM16F but this has been challenged. We investigated whether EGCG inhibits PS exposure in procoagulant platelets. PS exposure is often measured using fluorophore-conjugated annexin V. EGCG quenched annexin V-FITC fluorescence, which gives the appearance of inhibition of PS exposure. However, EGCG did not quench annexin V-APC fluorescence. Using this fluorophore, we show that EGCG does not inhibit annexin V binding to procoagulant platelets. We confirmed this by using NBD-labelled PS to monitor PS scrambling. EGCG did not quench NBD fluorescence and did not inhibit PS scrambling. Procoagulant platelets also release PS-exposing extracellular vesicles (EVs) that further propagate coagulation. Surprisingly, EGCG inhibited EV release. This inhibition required the gallate group of EGCG. In conclusion, EGCG does not inhibit PS exposure in procoagulant platelets but does inhibit the EV release. Future investigation of this inhibition may help us further understand how EVs are released by procoagulant platelets.

Multi-omics approaches for revealing the complexity of cardiovascular disease

The development and progression of cardiovascular disease (CVD) can mainly be attributed to the narrowing of blood vessels caused by atherosclerosis and thrombosis, which induces organ damage that will result in end-organ dysfunction characterized by events such as myocardial infarction or stroke. It is also essential to consider other contributory factors to CVD, including cardiac remodelling caused by cardiomyopathies and co-morbidities with other diseases such as chronic kidney disease. Besides, there is a growing amount of evidence linking the gut microbiota to CVD through several metabolic pathways. Hence, it is of utmost importance to decipher the underlying molecular mechanisms associated with these disease states to elucidate the development and progression of CVD. A wide array of systems biology approaches incorporating multi-omics data have emerged as an invaluable tool in establishing alterations in specific cell types and identifying modifications in signalling events that promote disease development. Here, we review recent studies that apply multi-omics approaches to further understand the underlying causes of CVD and provide possible treatment strategies by identifying novel drug targets and biomarkers. We also discuss very recent advances in gut microbiota research with an emphasis on how diet and microbial composition can impact the development of CVD. Finally, we present various biological network analyses and other independent studies that have been employed for providing mechanistic explanation and developing treatment strategies for end-stage CVD, namely myocardial infarction and stroke.

Incidence of and risk factors for new-onset deep venous thrombosis after intertrochanteric fracture surgery

This study aimed to investigate the incidence of and risk factors for postoperative new-onset deep venous thrombosis (PNO-DVT) following intertrochanteric fracture surgery. Information on 1672 patients who underwent intertrochanteric fracture surgery at our hospital between January 2016 and December 2019 was extracted from a prospective hip fracture database. Demographic information, surgical data, and preoperative laboratory indices were analysed. Receiver operating characteristic curve analysis, univariate analyses and binary logistic regression analyses were performed. The incidences of postoperative deep venous thrombosis (DVT) and PNO-DVT in inpatients after intertrochanteric fracture surgery were 11.5% (202 of 1751 patients) and 7.4% (123 of 1672 patients), respectively. PNO-DVT accounted for 60.9% of postoperative DVT. Additionally, there were 20 cases of central thrombosis (16.3%), 82 cases of peripheral thrombosis (66.7%), and 21 cases of mixed thrombosis (17.1%). In addition, 82.1% of PNO-DVTs were diagnosed within 8 days after surgery. The multivariate analysis revealed that age > 70 years, duration of surgery (> 197 min), type of anaesthesia (general), and comorbidities (≥ 3) were independent risk factors for the development of PNO-DVT after intertrochanteric fracture surgery. This study demonstrated a high incidence of PNO-DVT in inpatients after intertrochanteric fracture surgery. Therefore, postoperative examination for DVT should be routinely conducted for patients.

Risk assessment models for venous thromboembolism in hospitalised adult patients: a systematic review

INTRODUCTION

Hospital-acquired thrombosis accounts for a large proportion of all venous thromboembolism (VTE), with significant morbidity and mortality. This subset of VTE can be reduced through accurate risk assessment and tailored pharmacological thromboprophylaxis. This systematic review aimed to determine the comparative accuracy of risk assessment models (RAMs) for predicting VTE in patients admitted to hospital.

METHODS

A systematic search was performed across five electronic databases (including MEDLINE, EMBASE and the Cochrane Library) from inception to February 2021. All primary validation studies were eligible if they examined the accuracy of a multivariable RAM (or scoring system) for predicting the risk of developing VTE in hospitalised inpatients. Two or more reviewers independently undertook study selection, data extraction and risk of bias assessments using the PROBAST (Prediction model Risk Of Bias ASsessment Tool) tool. We used narrative synthesis to summarise the findings.

RESULTS

Among 6355 records, we included 51 studies, comprising 24 unique validated RAMs. The majority of studies included hospital inpatients who required medical care (21 studies), were undergoing surgery (15 studies) or receiving care for trauma (4 studies). The most widely evaluated RAMs were the Caprini RAM (22 studies), Padua prediction score (16 studies), IMPROVE models (8 studies), the Geneva risk score (4 studies) and the Kucher score (4 studies). C-statistics varied markedly between studies and between models, with no one RAM performing obviously better than other models. Across all models, C-statistics were often weak (<0.7), sometimes good (0.7-0.8) and a few were excellent (>0.8). Similarly, estimates for sensitivity and specificity were highly variable. Sensitivity estimates ranged from 12.0% to 100% and specificity estimates ranged from 7.2% to 100%.

CONCLUSION

Available data suggest that RAMs have generally weak predictive accuracy for VTE. There is insufficient evidence and too much heterogeneity to recommend the use of any particular RAM.

PROSPERO REGISTRATION NUMBER

Steve Goodacre, Abdullah Pandor, Katie Sworn, Daniel Horner, Mark Clowes. A systematic review of venous thromboembolism RAMs for hospital inpatients. PROSPERO 2020 CRD42020165778. Available from https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=165778https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=165778.

Hemostatic factors, inflammatory markers, and risk of incident venous thromboembolism: The Multi-Ethnic Study of Atherosclerosis

BACKGROUND

Several hemostatic factors and inflammatory markers are associated with the risk of incident venous thromboembolism (VTE), however, most existing data are from case-control studies in Caucasian populations.

OBJECTIVES

We aimed to prospectively confirm previous findings and explore less studied biomarkers in relation to VTE risk in a multi-racial/multi-ethnic cohort.

METHODS

Circulating levels of factor VIII, fibrinogen, D-dimer, plasmin-antiplasmin complex (PAP), C-reactive protein (CRP), and interleukin-6 (IL-6) were measured at baseline (2000-2002) in 6706 participants of the Multi-Ethnic Study of Atherosclerosis. Incident VTE was identified using hospitalization discharge codes from baseline to December 31, 2015. Hazard ratios (HRs) of VTE were estimated in Cox regression models.

RESULTS

There were 227 events during a median of 14 years of follow-up. Compared with participants in the lowest quartile, the HRs for those above the 95th percentile and p for trend across categories were 3.50 (95% confidence interval [CI] 1.98-6.19; p < .001) for D-dimer, 1.49 (95% CI 0.84-2.63; p = .02) for factor VIII, 1.32 (95% CI 0.76-2.28; p = .99) for fibrinogen, 1.92 (95% CI 1.08-3.42; p = .15) for PAP, 1.68 (95% CI 0.81-3.48; p = .08) for CRP, and 2.55 (95% CI 1.15-5.66; p = .07) for IL-6, after adjustment for demographics and body mass index. For CRP and IL-6, follow-up was restricted to 10 years because of violations of the proportional hazards assumption. No significant interactions by age/ethnicity were observed.

CONCLUSIONS

We demonstrated a fairly novel association between PAP and risk of incident VTE, and contributed further prospective confirmation regarding the associations of D-dimer, factor VIII, and IL-6 with VTE.

Relative risk of arterial and venous thromboembolism in persons with cancer vs. persons without cancer-a nationwide analysis

AIMS

An interrelation between cancer and thrombosis is known, but population-based studies on the risk of both arterial thromboembolism (ATE) and venous thromboembolism (VTE) have not been performed.

METHODS AND RESULTS

International Classification of Disease 10th Revision (ICD-10) diagnosis codes of all publicly insured persons in Austria (0-90 years) were extracted from the Austrian Association of Social Security Providers dataset covering the years 2006-07 (n = 8 306 244). Patients with a history of cancer or active cancer were defined as having at least one ICD-10 'C' diagnosis code, and patients with ATE and/or VTE as having at least one of I21/I24 (myocardial infarction), I63/I64 (stroke), I74 (arterial embolism), and I26/I80/I82 (venous thromboembolism) diagnosis code. Among 158 675 people with cancer, 8559 (5.4%) had an ATE diagnosis code and 7244 (4.6%) a VTE diagnosis code. In contrast, among 8 147 569 people without cancer, 69 381 (0.9%) had an ATE diagnosis code and 29 307 (0.4%) a VTE diagnosis code. This corresponds to age-stratified random-effects relative risks (RR) of 6.88 [95% confidence interval (CI) 4.81-9.84] for ATE and 14.91 (95% CI 8.90-24.95) for VTE. ATE proportion was highest in patients with urinary tract malignancies (RR: 7.16 [6.74-7.61]) and lowest in patients with endocrine cancer (RR: 2.49 [2.00-3.10]). The corresponding VTE proportion was highest in cancer of the mesothelium/soft tissue (RR: 19.35 [17.44-21.47]) and lowest in oropharyngeal cancer (RR: 6.62 [5.61-7.81]).

CONCLUSION

The RR of both ATE and VTE are significantly higher in persons with cancer. Our population-level meta-data indicate a strong association between cancer, ATE and VTE, and support the concept of shared risk factors and pathobiology between these diseases.Relative risk of ATE and VTE in persons with a cancer diagnosis code versus persons without a cancer diagnosis code.

Thrombotic Events and Anticoagulants in Beta-thalassemia Patients with Focus on Anticoagulants for Atrial Fibrillation: A Brief Review

Despite many advances in the diagnosis and treatment of beta-thalassemia patients in recent years and their longevity and quality of life which has been greatly increased, many of these patients have other life-threatening risks. The prevalence of atrial fibrillation in beta-thalassemia patients and its related thromboembolism, stroke, and mortality have been increased in the last few years. Appropriate anticoagulant therapy may help to prevent the incidence or recurrence of thromboembolism. So far warfarin is the most widely used drug. Aspirin should use with caution in these patients because of its resistance to aspirin over time, which can increase the risk of thromboembolism. Direct oral anticoagulants (DOACs) are widely used to prevent embolism in coronary artery disease and venous thromboembolism, but their use in thalassemia patients is still very limited. More high-quality researches and clinical trials are needed to prove their effectiveness and safety for atrial fibrillation in beta-thalassemia patients.

A phase I, single and continuous dose administration study on the safety, tolerability, and pharmacokinetics of neorudin, a novel recombinant anticoagulant protein, in healthy subjects

The aim of this study was to evaluate the tolerability, safety, and pharmacokinetics of single and continuous dose administration of recombinant neorudin (EPR-hirudin, EH) by intravenous administration in healthy subjects, and to provide a safe dosage range for phase II clinical research. Forty-four subjects received EH as a single dose of between 0.2 and 2.0 mg/kg by intravenous bolus and drip infusion. In addition, 18 healthy subjects were randomly divided into three dose groups (0.15, 0.30, and 0.45 mg/kg/h) with 6 subjects in each group for the continuous administration trial. Single or continuous doses of neorudin were generally well tolerated by healthy adult subjects. There were no serious adverse events (SAEs), and all adverse events (AEs) were mild to moderate. Moreover, no subjects withdrew from the trial because of AEs. There were no clinically relevant changes in physical examination results, clinical chemistry, urinalysis, or vital signs. The incidence of adverse events was not significantly related to drug dose or systemic exposure. After single-dose and continuous administration, the serum EH concentration reached its peak at 5 min, and the exposure increased with the increase in the administered dose. The mean half-life (T_1/2 ), clearance (Cl), and apparent volume of distribution (Vd) of EH ranged from 1.7 to 2.5 h, 123.9 to 179.7 ml/h/kg, and 402.7 to 615.2 ml/kg, respectively. The demonstrated safety, tolerability, and pharmacokinetic characteristics of EH can be used to guide rational drug dosing and choose therapeutic regimens in subsequent clinical studies. Clinical trial registration: Chinadrugtrials.org identifier: CTR20160444.

Structural and functional analysis of the simultaneous binding of two duplex/quadruplex aptamers to human α-thrombin

The long-range communication between the two exosites of human α-thrombin (thrombin) tightly modulates the protein-effector interactions. Duplex/quadruplex aptamers represent an emerging class of very effective binders of thrombin. Among them, NU172 and HD22 aptamers are at the forefront of exosite I and II recognition, respectively. The present study investigates the simultaneous binding of these two aptamers by combining a structural and dynamics approach. The crystal structure of the ternary complex formed by the thrombin with NU172 and HD22_27mer provides a detailed view of the simultaneous binding of these aptamers to the protein, inspiring the design of novel bivalent thrombin inhibitors. The crystal structure represents the starting model for molecular dynamics studies, which point out the cooperation between the binding at the two exosites. In particular, the binding of an aptamer to its exosite reduces the intrinsic flexibility of the other exosite, that preferentially assumes conformations similar to those observed in the bound state, suggesting a predisposition to interact with the other aptamer. This behaviour is reflected in a significant increase of the anticoagulant activity of NU172 when the inactive HD22_27mer is bound to exosite II, providing a clear evidence of the synergic action of the two aptamers.

Compression hosiery to avoid post-thrombotic syndrome (CHAPS) protocol for a randomised controlled trial (ISRCTN73041168)

INTRODUCTION

Up to 50% of patients develop post-thrombotic syndrome (PTS) after an above knee deep vein thrombosis (DVT). The aim of the study was to determine the effect of graduated compression stockings in preventing PTS after DVT.

METHODS AND ANALYSIS

Pragmatic, UK multicentre randomised trial in adults with first above knee DVT. The standard of care arm is anticoagulation. The intervention arm will receive anticoagulation plus stockings (European class II, 23-32 mm Hg compression) worn for a median of 18 months. The primary endpoint is PTS using the Villalta score. Analysis of this will be through a time to event approach and cumulative incidence at median 6, 12 and 18 months. An ongoing process evaluation will examine factors contributing to adherence to stockings to understand if and how the behavioural interventions were effective.

ETHICS AND DISSEMINATION

UK research ethics committee approval (reference 19/LO/1585). Dissemination though the charity Thrombosis UK, the Imperial College London website, peer-reviewed publications and international conferences.

TRIAL REGISTRATION NUMBER

ISRCTN registration number 73041168.

Predicting Recurrent Venous Thromboembolism in Patients With Deep-Vein Thrombosis: Development and Internal Validation of a Potential New Prediction Model (Continu-8)

Background: Previous prediction models for recurrent thromboembolism (VTE) are often complicated to apply and have not been implemented widely.

Aim: To develop and internally validate a potential new prediction model for recurrent VTE that can be used without stopping anticoagulant treatment for D-dimer measurements in patients with provoked and unprovoked DVT.

Methods: Cohort data of 479 patients treated in a clinical care pathway at Maastricht University Medical Center were used. Predictors for the Cox proportional hazards model (unprovoked DVT, male gender, factor VIII levels) were derived from literature and using forward selection procedure. The scoring rule was internally validated using bootstrapping techniques and the predictive ability was compared to existing prediction models.

Results: Patients were followed for a median of 3.12 years after stopping anticoagulation treatment (IQR 0.78, 3.90). Sixty-four of 479 patients developed recurrent VTE (13%). The scoring rule consisted of unprovoked DVT (yes: 2 points), male sex (yes: 1 point), and factor VIII > 213 % (yes: 2 points) and was categorized into three groups [i.e., low risk (score 0), medium risk (scores 1, 2, or 3) and high risk (scores 4 and 5)]. The concordance statistic was 0.68 (95% CI: 0.61, 0.75).

Conclusion: The discriminative ability of the new Continu-8 score was adequate. Future studies shall verify this score in an independent setting without stopping anticoagulation treatment.

Genetic Labeling of Cells Allows Identification and Tracking of Transgenic Platelets in Mice

Background: The use of knock-out mouse models is crucial to understand platelet activation and aggregation. Methods: Analysis of the global double fluorescent Cre reporter mouse mT/mG that has been crossbred with the megakaryocyte/platelet specific PF4-Cre mouse. Results: Platelets show bright mT (PF4-Cre negative) and mG (PF4-Cre positive) fluorescence. However, a small proportion of leukocytes was positive for mG fluorescence in PF4-Cre positive mice. In mT/mG;PF4-Cre mice, platelets, and megakaryocytes can be tracked by their specific fluorescence in blood smear, hematopoietic organs and upon thrombus formation. No differences in platelet activation and thrombus formation was observed between mT/mG;PF4-Cre positive and negative mice. Furthermore, hemostasis and in vivo thrombus formation was comparable between genotypes as analyzed by intravital microscopy. Transplantation studies revealed that bone marrow of mT/mG;PF4-Cre mice can be transferred to C57BL/6 mice. Conclusions: The mT/mG Cre reporter mouse is an appropriate model for real-time visualization of platelets, the analysis of cell morphology and the identification of non-recombined platelets. Thus, mT/mG;PF4-Cre mice are important for the analysis of platelet-specific knockout mice. However, a small proportion of leukocytes exhibit mG fluorescence. Therefore, the analysis of platelets beyond hemostasis and thrombosis should be critically evaluated when recombination of immune cells is increased.

Performance of the Wells score in predicting deep vein thrombosis in medical and surgical hospitalized patients with or without thromboprophylaxis: The R-WITT study

The Wells score had shown weak performance to determine pre-test probability of deep vein thrombosis (DVT) for inpatients. So, we evaluated the impact of thromboprophylaxis on the utility of the Wells score for risk stratification of inpatients with suspected DVT. This bicentric cross-sectional study from February 1, 2018 to January 31, 2019 included consecutive medical and surgical inpatients who underwent lower limb ultrasound study for suspected DVT. Wells score clinical predictors were assessed by both ordering and vascular physicians within 24 h after clinical suspicion of DVT. Primary outcome was the Wells score's accuracy for pre-test risk stratification of suspected DVT, accounting for anticoagulation (AC) treatment (thromboprophylaxis for ⩾ 72 hours or long-term anticoagulation). We compared prevalence of proximal DVT among the low, moderate and high pre-test probability groups. The discrimination accuracy was defined as area under the receiver operating characteristics (ROC) curve. Of the 415 included patients, 30 (7.2%) had proximal DVT. Prevalence of proximal DVT was lower than expected in all pre-test probability groups. The prevalence in low, moderate and high pre-test probability groups was 0.0%, 3.1% and 8.2% (p = 0.22) and 1.7%, 4.2% and 25.8% (p < 0.001) for inpatients with or without AC, respectively. Area under ROC curves for discriminatory accuracy of the Wells score, for risk of proximal DVT with or without AC, was 0.72 and 0.88, respectively. The Wells score performed poorly for discrimination of risk for proximal DVT in hospitalized patients with AC but performed reasonably well among patients without AC; and showed low inter-rater reliability between physicians. ClinicalTrials.gov Identifier: NCT03784937.

Venous thromboembolism in Asia and worldwide: Emerging insights from GARFIELD-VTE

BACKGROUND

Although epidemiological studies report a lower risk of venous thromboembolism (VTE) than in the Western world, VTE rates in Asia may be underestimated. Furthermore, it is uncertain whether VTE outcomes differ in Asia and the rest of the world (ROW).

METHODS

GARFIELD-VTE is a global, prospective, non-interventional study of real-world treatment practices. In this study, we compared baseline characteristics, treatment patterns, and 12-month outcomes in Asia and ROW.

RESULTS

Of the 10,684 enrolled patients, 1822 (17.1%) were Asian (China n = 420, Hong Kong n = 98, Japan n = 148, Malaysia n = 244, South Korea n = 343, Taiwan n = 232, Thailand n = 337). Compared with ROW patients, those from Asia were more often female (57.4% vs. 48.0%), non-smokers (74.0% vs. 58.9%) and had a lower BMI (24.8 kg/m² vs. 29.1 kg/m²). Asian patients were more likely to be managed in the hospital (86.9% vs. 70.4%) and to have active cancer (19.8% vs. 8.1%) or a history of cancer (19.1% vs. 12.0%). Asian patients received no anticoagulation more frequently than ROW patients (6.5% vs. 2.1%). Over 12-months follow-up, the rate of all-cause mortality (per 100 person-years [95% confidence interval]) was higher in Asians (15.2 [13.4-17.3] vs. 5.9 [5.4-6.5]). Adjusted hazard ratios indicated a higher risk of all-cause mortality in Asian patients than the ROW (1.32 [1.08-1.62]). The frequencies of major bleeding and recurrent VTE were similar.

CONCLUSION

Asian patients have different risk profiles, treatment patterns and a higher risk of mortality compared with the ROW.

Age and Origin of the Founder Antithrombin Budapest 3 (p.Leu131Phe) Mutation; Its High Prevalence in the Roma Population and Its Association With Cardiovascular Diseases

Background: Antithrombin (AT) is one of the most important regulator of hemostasis. AT Budapest 3 (ATBp3) is a prevalent type II heparin-binding site (IIHBS) deficiency due to founder effect. Thrombosis is a complex disease including arterial (ATE) and venous thrombotic events (VTE) and the Roma population, the largest ethnic minority in Europe has increased susceptibility to these diseases partly due to their unfavorable genetic load. We aimed to calculate the age and origin of ATBp3 and to explore whether the frequency of it is higher in the Roma population as compared with the general population from the corresponding geographical area. We investigated the association of ATBp3 with thrombotic events in well-defined patients' populations in order to refine the recommendation when testing for ATBp3 is useful.

Methods and Results: Prevalence of ATBp3, investigated in large samples (n = 1,000 and 1,185 for general Hungarian and Roma populations, respectively) was considerably high, almost 3%, among Roma and the founder effect was confirmed in their samples, while it was absent in the Hungarian general population. Age of ATBp3—as calculated by analysis of 8 short tandem repeat sequences surrounding SERPINC1—was dated back to XVII Century, when Roma migration in Central and Eastern Europe occurred. In our IIHBS cohort (n = 230), VTE was registered in almost all ATBp3 homozygotes (93%) and in 44% of heterozygotes. ATE occurred with lower frequency in ATBp3 (around 6%); it was rather associated with AT Basel (44%). All patients with ATE were young at the time of diagnosis. Upon investigating consecutive young (<40 years) patients with ATE (n = 92) and VTE (n = 110), the presence of ATBp3 was remarkable.

Conclusions: ATBp3, a 400-year-old founder mutation is prevalent in Roma population and its Roma origin can reasonably be assumed. By the demonstration of the presence of ATBp3 in ATE patients, we draw the attention to consider type IIHBS AT deficiency in the background of not only VTE but also ATE, especially in selected populations as young patients without advanced atherosclerosis. We recommend including the investigation of ATBp3 as part of thrombosis risk assessment and stratification in Roma individuals.

Targeting Thymidine Phosphorylase With Tipiracil Hydrochloride Attenuates Thrombosis Without Increasing Risk of Bleeding in Mice

OBJECTIVE

Current antiplatelet medications increase the risk of bleeding, which leads to a clear clinical need in developing novel mechanism-based antiplatelet drugs. TYMP (Thymidine phosphorylase), a cytoplasm protein that is highly expressed in platelets, facilitates multiple agonist-induced platelet activation, and enhances thrombosis. Tipiracil hydrochloride (TPI), a selective TYMP inhibitor, has been approved by the Food and Drug Administration for clinical use. We tested the hypothesis that TPI is a safe antithrombotic medication. Approach and Results: By coexpression of TYMP and Lyn, GST (glutathione S-transferase) tagged Lyn-SH3 domain or Lyn-SH2 domain, we showed the direct evidence that TYMP binds to Lyn through both SH3 and SH2 domains, and TPI diminished the binding. TYMP deficiency significantly inhibits thrombosis in vivo in both sexes. Pretreatment of platelets with TPI rapidly inhibited collagen- and ADP-induced platelet aggregation. Under either normal or hyperlipidemic conditions, treating wild-type mice with TPI via intraperitoneal injection, intravenous injection, or gavage feeding dramatically inhibited thrombosis without inducing significant bleeding. Even at high doses, TPI has a lower bleeding side effect compared with aspirin and clopidogrel. Intravenous delivery of TPI alone or combined with tissue plasminogen activator dramatically inhibited thrombosis. Dual administration of a very low dose of aspirin and TPI, which had no antithrombotic effects when used alone, significantly inhibited thrombosis without disturbing hemostasis.

CONCLUSIONS

This study demonstrated that inhibition of TYMP, a cytoplasmic protein, attenuated multiple signaling pathways that mediate platelet activation, aggregation, and thrombosis. TPI can be used as a novel antithrombotic medication without the increase in risk of bleeding.

Individualised Risk Assessments for Recurrent Venous Thromboembolism: New Frontiers in the Era of Direct Oral Anticoagulants

Venous thromboembolism (VTE) is a leading cause of morbidity and mortality and is associated with high recurrence rates. The introduction of direct oral anticoagulants (DOACs) in the 2010s has changed the landscape of VTE management. DOACs have become the preferred anticoagulant therapy for their ease of use, predictable pharmacokinetics, and improved safety profile. Increasingly, guidelines have recommended long term anticoagulation for some indications such as following first unprovoked major VTE, although an objective individualised risk assessment for VTE recurrence remains elusive. The balance of preventing VTE recurrence needs to be weighed against the not insignificant bleeding risk, which is cumulative with prolonged use. Hence, there is a need for an individualised, targeted approach for assessing the risk of VTE recurrence, especially in those patients in whom the balance between benefit and risk of long-term anticoagulation is not clear. Clinical factors alone do not provide the level of discrimination required on an individual level. Laboratory data from global coagulation assays and biomarkers may provide enhanced risk assessment ability and are an active area of research. A review of the prediction models and biomarkers for assessing VTE recurrence risk is provided, with an emphasis on contemporary developments in the era of DOACs and global coagulation assays.

Can we predict and prevent the postthrombotic syndrome?

Postthrombotic syndrome (PTS) remains one of the major late complications of deep vein thrombosis (DVT) with a reported prevalence from 10 to 50%. Many factors were found to be related with the development and severity of PTS such as ipsilateral recurrent DVT, advanced age, obesity, ilio-femoral DVT and primary chronic venous disease presence. Some PTS prediction models have been proposed based on risk factor weight. However, it is still difficult to predict which patient with DVT will develop PTS and thus, the clinical application of these models remains limited. Among the identified problems the heterogeneity of the DVT patient population together with the variety of PTS clinical presentations and difficulties concerning PTS severity assessment should be mentioned. Difficulties on the implementation of the specific and objective PTS identification method have also the significant influence on the research focusing on PTS prevention modalities including risk factor modification, compression treatment, anticoagulation and invasive DVT treatment. In this review, the current approach and knowledge on PTS prediction and prevention are presented, including the conservative and invasive DVT treatment possibilities.

Percutaneous thrombectomy using a novel single session device for acute iliofemoral deep vein thrombosis

A 74-year-old woman presented with acute symptomatic left thigh and calf swelling; imaging demonstrated evidence of occlusive thrombosis from the upper left common iliac vein to the mid-thigh. Single session zero-thrombolysis venous thrombectomy was performed using the ReVene^TM Thrombectomy Catheter.

Clinical Outcomes of Incidental Venous Thromboembolism in Cancer and Noncancer Patients: The SWIss Venous ThromboEmbolism Registry (SWIVTER)

OBJECTIVE

 In patients with cancer-associated venous thromboembolism (VTE), the risk of recurrence is similar after incidental and symptomatic events. It is unknown whether the same applies to incidental VTE not associated with cancer.

METHODS AND RESULTS

 We compared baseline characteristics, anticoagulation therapy, all-cause mortality, and VTE recurrence rates at 90 days between patients with incidental (n = 131; 52% without cancer) and symptomatic (n = 1,931) VTE included in the SWIss Venous ThromboEmbolism Registry (SWIVTER). After incidental VTE, 114 (87%) patients received anticoagulation therapy for at least 3 months. The mortality rate was 9.2% after incidental and 8.4% after symptomatic VTE for hazard ratio (HR) 1.10 (95% confidence interval [CI] 0.49-2.50). After adjustment for competing risk of death, recurrence rate was 3.1 versus 2.8%, respectively, for sub-HR 1.07 (95% CI 0.39-2.93). These results were consistent among cancer (mortality: 15.9% vs. 12.6%; HR 1.32, 95% CI 0.67-2.59; recurrence: 4.8% vs. 4.7%; HR 1.02, 95% CI 0.30-3.42) and noncancer patients (mortality: 2.9% vs. 2.1%; HR 1.37, 95% CI 0.33-5.73; recurrence: 1.5% vs. 2.3%; HR 0.63, 95% CI 0.09-4.58). Patients with incidental VTE who received anticoagulation therapy for at least 3 months had lower mortality (4% vs. 41%) and recurrence rate (1% vs. 18%) compared with those who did not.

CONCLUSION

 In SWIVTER, more than half of incidental VTE events occurred in noncancer patients who often received anticoagulation therapy. Among noncancer patients, early mortality and recurrence rates were similar after incidental versus symptomatic VTE. Our findings suggest that anticoagulation therapy for incidental VTE may be beneficial regardless of the presence of cancer.

Effect of anticoagulants on fibrin clot structure: A comparison between vitamin K antagonists and factor Xa inhibitors

BACKGROUND

Abnormal clot structure has been identified in patients with thrombotic disorders. Anticoagulant therapy offers clear benefits for thrombosis prevention and treatment by reducing blood clot formation and size; nevertheless, there are limited data on the effects of different anticoagulants, where clotting is initiated with different triggers, on clot structure.

OBJECTIVES

Our aim was to investigate the effects of vitamin K antagonists and factor Xa inhibitors on clot structure.

METHODS

Clots from pooled plasma spiked with rivaroxaban, apixaban, or enoxaparin, as well as plasma from patients on warfarin, were compared to plasma without anticoagulation. The kinetic profile of polymerizing clots was obtained by turbidity, fiber density was determined by confocal microscopy, clot pore size was investigated by permeation, and fiber size was analyzed using scanning electron microscopy. Clotting agonist was either tissue factor or thrombin.

RESULTS

Following clotting with tissue factor, all anticoagulated clots had a significantly increased lag time, with the exception of enoxaparin. Rivaroxaban additionally led to significantly less dense and more permeable clots, with thicker fibers. In contrast, turbidity analysis following initiation with thrombin showed few effects of anticoagulation, with only enoxaparin leading to a prolonged lag time. Enoxaparin clots made with thrombin were less dense and more permeable.

CONCLUSION

Our results show that anticoagulants modulate clot structure particularly when induced by tissue factor, most likely due to reduction of thrombin generation. We propose that the effects of different anticoagulants could be assessed with a global clot structure measurement such as permeation or turbidity, providing information on clot phenotype.

Injury measurements improve interpretation of thrombus formation data in the cremaster arteriole laser-induced injury model of thrombosis

Background

The cremaster arteriole laser-induced injury model is a powerful technique with which to investigate the molecular mechanisms that drive thrombus formation. This model is capable of direct visualization and quantification of accumulation of thrombus constituents, including both platelets and fibrin. However, a large degree of variability in platelet accumulation and fibrin formation is observed between thrombi. Strategies to understand this variability will enhance performance and standardization of the model. We determined whether ablation injury size contributes to variation in platelet accumulation and fibrin formation and, if so, whether incorporating ablation injury size into measurements reduces variation.

Methods

Thrombus formation was initiated by laser-induced injury of cremaster arterioles of mice (n=59 injuries). Ablation injuries within the vessel wall were consistently identified and quantified by measuring the length of vessel wall injury observed immediately following laser-induced disruption. Platelet accumulation and fibrin formation as detected by fluorescently-labeled antibodies were captured by digital intra-vital microscopy.

Results

Laser-induced disruption of the vessel wall resulted in ablation injuries of variable length (18-95 μm) enabling interrogation of the relationship between injury severity and thrombus dynamics. Strong positive correlations were observed between vessel injury length and both platelet and fibrin when the data are transformed as area under the curve (Spearman r = 0.80 and 0.76 respectively). Normalization of area under the curve measurements by injury length reduced intraclass coefficients of variation among thrombi and improved hypothesis testing when comparing different data sets.

Conclusions

Measurement of vessel wall injury length provides a reliable and robust marker of injury severity. Injury length can effectively normalize measurements of platelet accumulation and fibrin formation improving data interpretation and standardization.

Discovery of Benzyl Tetraphosphonate Derivative as Inhibitor of Human Factor Xia

The inhibition of factor XIa (FXIa) is a trending paradigm for the development of new generations of anticoagulants without a substantial risk of bleeding. In this report, we present the discovery of a benzyl tetra-phosphonate derivative as a potent and selective inhibitor of human FXIa. Biochemical screening of four phosphonate/phosphate derivatives has led to the identification of the molecule that inhibited human FXIa with an IC50 value of ∼7.4 μM and a submaximal efficacy of ∼68 %. The inhibitor was at least 14-fold more selective to FXIa over thrombin, factor IXa, factor Xa, and factor XIIIa. It also inhibited FXIa-mediated activation of factor IX and prolonged the activated partial thromboplastin time of human plasma. In Michaelis-Menten kinetics experiment, inhibitor 1 reduced the VMAX of FXIa hydrolysis of a chromogenic substrate without significantly affecting its KM suggesting an allosteric mechanism of inhibition. The inhibitor also disrupted the formation of FXIa - antithrombin complex and inhibited thrombin-mediated and factor XIIa-mediated formation of FXIa from its zymogen factor XI. Inhibitor 1 has been proposed to bind to or near the heparin/polyphosphate-binding site in the catalytic domain of FXIa. Overall, inhibitor 1 is the first benzyl tetraphosphonate small molecule that allosterically inhibits human FXIa, blocks its physiological function, and prevents its zymogen activation by other clotting factors under in vitro conditions. Thus, we put forward benzyl tetra-phosphonate 1 as a novel lead inhibitor of human FXIa to guide future efforts in the development of allosteric anticoagulants.

Oral Contraceptives and Venous Thromboembolism: Focus on Testing that May Enable Prediction and Assessment of the Risk

Combined oral contraceptives (COCs) induce several changes in the levels of coagulation factors. The levels of procoagulant factors are often increased, while levels of anticoagulant factors are decreased. Fibrinolysis is also affected, even if the effect seems to be more counterbalanced by opposite regulation of profibrinolytic and antifibrinolytic factors. These effects on hemostasis are more pronounced with third- or fourth-generation COC compared with second-generation COC. Venous thromboembolism (VTE) risk increases when multiple risk factors, including genetic and environmental, are present simultaneously. COC use causes changes in coagulation that modify the prothrombotic state induced by preexisting hemostatic alterations in a supra-additive manner. Therefore, testing appears to be of importance not only before implementing COC but also to monitor any potential thrombogenicity induced by COC therapy. Inherited genetic factors, such as factor V Leiden, G20210A prothrombin mutation, antithrombin, protein C or protein S deficiencies, non-O blood group, as well as CYP2C9*2 and the rs4379368 mutations, have all been identified as genetic predictive risk factors of VTE in women. Nevertheless, the screening of these genetic biomarkers is not capable of assessing the phenotypic expression of the risk. This review will focus on the different options for screening the thrombogenic status in this population. Specific attention will be given to the endogenous thrombin potential-based activated protein C resistance, a test aiming at assessing the thrombogenicity induced by hormonal therapies and inherited or acquired thrombophilia.

Development and validation of an informative manual on venous thromboembolism for the lay population

Objective

To develop an informative manual on venous thromboembolism prevention for the lay population and to estimate evidences of content and face validity.

Methods

A methodological study conducted in three stages. The first stage was the preparation of the manual, followed by content validation with cardiovascular specialists who judged clarity, theoretical relevance and practical pertinence on a 4-point Likert scale. Items with a content validity index ≤0.75 were revised and re-evaluated. The last stage was the face validation by lay people, who were interviewed regarding item understanding and visual appearance. Items with more than 80.0% positive opinions were considered adequate.

Results

The manual was developed containing nine illustrations, definition of the disease, risk factors, signs and symptoms, and preventive measures. In the first assessment round, the validity index was 1.0 for the text of all sections, with suggestions for language adjustments. As to the illustrations, the validity indexes ranged from 0.67 to 1.0. In the second round, the validity index reached 1.0 for all items. A total of 40 lay people participated in the face validation, and all considered the paper type and font size appropriate, as well as the font used as readable; 97.5% were able to understand the information contained in the manual; 98.0% considered it esthetically beautiful; and 90.0% considered the reading not tiresome.

Conclusion

The informative manual on venous thromboembolism prevention was prepared, its content validated by experts, and considered appropriate by the lay population. These results suggest that the manual may be used as a preventive educational strategy for venous thromboembolism.

Factor XIIIa inhibitors as potential novel drugs for venous thromboembolism

Human factor XIIIa (FXIIIa) is a multifunctional transglutaminase with a significant role in hemostasis. FXIIIa catalyzes the last step in the coagulation process. It stabilizes the blood clot by cross-linking the α- and γ-chains of fibrin. It also protects the newly formed clot from plasmin-mediated fibrinolysis, primarily by cross-linking α2-antiplasmin to fibrin. Furthermore, FXIIIa is a major determinant of clot size and clot's red blood cells content. Therefore, inhibitors targeting FXIIIa have been considered to develop a new generation of anticoagulants to prevent and/or treat venous thromboembolism. Several inhibitors of FXIIIa have been discovered or designed including active site and allosteric site small molecule inhibitors as well as natural and modified polypeptides. This work reviews the structural, biochemical, and pharmacological aspects of FXIIIa inhibitors so as to advance their molecular design to become more clinically relevant.