Thrombosis: a major contributor to the global disease burden

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.

Venous Thromboembolism Research Priorities: A Scientific Statement From the American Heart Association and the International Society on Thrombosis and Haemostasis

Venous thromboembolism is a major cause of morbidity and mortality. The impact of the US Surgeon General's The Surgeon General's Call to Action to Prevent Deep Vein Thrombosis and Pulmonary Embolism in 2008 has been lower than expected given the public health impact of this disease. This scientific statement highlights future research priorities in venous thromboembolism, developed by experts and a crowdsourcing survey across 16 scientific organizations. At the fundamental research level (T0), researchers need to identify pathobiological causative mechanisms for the 50% of patients with unprovoked venous thromboembolism and to better understand mechanisms that differentiate hemostasis from thrombosis. At the human level (T1), new methods for diagnosing, treating, and preventing venous thromboembolism will allow tailoring of diagnostic and therapeutic approaches to individuals. At the patient level (T2), research efforts are required to understand how foundational evidence impacts care of patients (eg, biomarkers). New treatments, such as catheter-based therapies, require further testing to identify which patients are most likely to experience benefit. At the practice level (T3), translating evidence into practice remains challenging. Areas of overuse and underuse will require evidence-based tools to improve care delivery. At the community and population level (T4), public awareness campaigns need thorough impact assessment. Large population-based cohort studies can elucidate the biological and environmental underpinnings of venous thromboembolism and its complications. To achieve these goals, funding agencies and training programs must support a new generation of scientists and clinicians who work in multidisciplinary teams to solve the pressing public health problem of venous thromboembolism.

Synthesis and Biological Evaluation of Thio-Derivatives of 2-Hydroxy-1,4-Naphthoquinone (Lawsone) as Novel Antiplatelet Agents

We designed and synthesized in water, using conventional heating and microwave irradiation, new thio-derivatives of 2-hydroxy-1,4-naphthoquinone, a naturally occurring pigment known as lawsone or hennotannic acid, thus improving their antiplatelet activity with relevance to their potential future use in thrombus formation treatment. The structure-activity relationship showed that the thiophenyl moiety enhances the antiplatelet activity. Moreover, the position and nature of the substituent at the phenyl ring have a key effect on the observed biological activity. Compound 4 (2-((4-bromophenyl)thio)-3-hydroxynaphthalene-1,4-dione) was the most active derivative, presenting IC₅₀ values for platelet aggregation inhibition of 15.03 ± 1.52 μM for TRAP-6, and 5.58 ± 1.01 μM for collagen. Importantly, no cytotoxicity was observed. Finally, we discussed the structure-activity relationships of these new lawsone thio-derivatives on inhibition of TRAP-6- and collagen-induced platelet aggregation.

Nephrotic syndrome-associated hypercoagulopathy is alleviated by both pioglitazone and glucocorticoid which target two different nuclear receptors

BACKGROUND

Thrombosis is a potentially life-threatening nephrotic syndrome (NS) complication. We have previously demonstrated that hypercoagulopathy is proportional to NS severity in rat models and that pioglitazone (Pio) reduces proteinuria both independently and in combination with methylprednisolone (MP), a glucocorticoid (GC). However, the effect of these treatments on NS-associated hypercoagulopathy remains unknown. We thus sought to determine the ability of Pio and GC to alleviate NS-associated hypercoagulopathy.

METHODS

Puromycin aminonucleoside-induced rat NS was treated with sham, Low- or High-dose MP, Pio, or combination (Pio + Low-MP) and plasma was collected at day 11. Plasma samples were collected from children with steroid-sensitive NS (SSNS) and steroid-resistant NS (SRNS) upon presentation and after 7 weeks of GC therapy. Plasma endogenous thrombin potential (ETP), antithrombin (AT) activity, and albumin (Alb) were measured using thrombin generation, amidolytic, and colorimetric assays, respectively.

RESULTS

In a rat model of NS, both High-MP and Pio improved proteinuria and corrected hypoalbuminemia, ETP and AT activity (p < .05). Proteinuria (p = .005) and hypoalbuminemia (p < .001) were correlated with ETP. In childhood NS, while ETP was not different at presentation, GC therapy improved proteinuria, hypoalbuminemia, and ETP in children with SSNS (p < .001) but not SRNS (p = .330).

CONCLUSIONS

Both Pio and GC diminish proteinuria and significantly alleviate hypercoagulopathy. Both Pio and MP improved hypercoagulopathy in rats, and successful GC therapy (SSNS) also improved hypercoagulopathy in childhood NS. These data suggest that even a partial reduction in proteinuria may reduce NS-associated thrombotic risk.

Brain Natriuretic Peptide and Troponin T in Patients With Acute Pulmonary Embolism and Grade 3 Obesity: A Retrospective Analysis

Introduction The interpretation of brain natriuretic peptide (BNP) and Troponin T (TnT) in patients with obesity is very challenging. The applicability of these biomarkers as prognostic indicators of increased mortality in pulmonary embolism (PE) in patients with Grade 3 obesity has yet to be determined. Methods To investigate whether the combination of BNP and TnT may help to identify patients at low risk for short-term mortality, we assessed 92 patients admitted with the diagnosis of PE and Grade 3 obesity. The study endpoint was all-cause mortality at 30 days. Results The negative predictive value (NPV) of these tests combined is 98.8%; however, we were not able to detect a statistically significant difference between the patients who had a BNP < 100 pg/mL and TnT < 0.03 ng/mL and the other individuals who had either BNP ≥ 100 pg/mL or TnT ≥ 0.03 or both. The mortality rate was 5.43% within 30 days of the diagnosis. The logistic regression analysis using BNP and troponin as continuous variables identified BNP (p < 0.005) as an independent predictor for 30 days mortality. Receiver operating characteristic (ROC) analysis determined that a BNP level of 684 pg/mL was the cutoff level to predict mortality in the population studied. Conclusions Our results support that BNP and TnT levels retain an excellent NPV among patients with PE and Grade 3 obesity. BNP testing could be an independent predictor of high-risk patients in this population. The low incidence of all-cause mortality in this study (5.43%) is primarily explained by the more frequent use (9.75%) of systemic or catheter-based thrombolysis associated with a lower rate of major bleeding compared to the general population.

Association of inflammatory skin diseases with venous thromboembolism in US adults

Patients with certain inflammatory skin diseases have multiple risk factors for venous thromboembolism (VTE). The objective of the study was to determine whether atopic dermatitis (AD), psoriasis, pemphigus, pemphigoid and/or hidradenitis is associated with VTE in US adults. Data were analyzed from the 2002-2012 Nationwide Inpatient Sample, a representative cohort of US hospitalizations (N = 72,512,581 adults, including 1,389,292 with VTE). In multivariable logistic regression models including age, sex, insurance, household income and race/ethnicity, hospitalization for AD (adjusted odds ratio [95% confidence intervals] 1.22 [1.17-1.27]), pemphigus (1.96 [1.68-2.28]) and pemphigoid (1.64 [1.47-1.83]) was associated with VTE. These associations remained significant in virtually all patient subsets, including males and females, different age groups and those with and without long-term corticosteroid use. In particular, AD, pemphigus and pemphigoid were each associated with DVT and PE. VTE was associated with increased inpatient length of stay, cost of care and mortality across all the inflammatory skin diseases. HS and psoriasis were not consistently associated with VTE. AD, pemphigus and pemphigoid and some subsets of patients with HS were associated with higher odds of hospitalization for VTE. Patients with these inflammatory skin diseases may benefit from increased screening and prevention of VTE.

Global epidemiology of venous thromboembolism in people with active tuberculosis: a systematic review and meta-analysis

Despite the wide range of studies supporting an association between exposure to active tuberculosis and risk of venous thromboembolism (VTE), the current systematic review and meta-analysis is the first study assessing the global epidemiology of VTE in patients having active tuberculosis. In this systematic review and meta-analysis, EMBASE, Medline, and Web of Science were searched to identify observational studies, published until December 15, 2019, and reporting on venous thromboembolism in patients with active tuberculosis. No language restriction was applied. Studies were synthetized using a random-effect model. This review is registered with PROSPERO, CRD42019130347. We included 9 studies with an overall total of 16,190 patients with active tuberculosis. The prevalence of VTE was 3.5% (95% CI 2.2-5.2) in patients with active tuberculosis. Furthermore, we found a prevalence of pulmonary embolism (PE) at 5.8% (95% CI 2.2-10.7) and for deep vein thrombosis (DVT) at 1.3% (95% CI 0.8-2.0) in patients with active tuberculosis. Patients with active tuberculosis had a higher risk for VTE (OR 2.90; 95% CI 2.30-3.67), DVT (OR 1.56; 95% CI 1.14-2.14), and PE (OR 3.58; 95% CI 2.54-5.05). This study suggests that VTE is not rare among patients with active TB. Cost-effective preventive strategies and interventions to curb this dreadful burden of VTE among people with active TB are needed.

Venous thromboembolism research priorities: A scientific statement from the American Heart Association and the International Society on Thrombosis and Haemostasis

Venous thromboembolism (VTE) is a major cause of morbidity and mortality. The impact of the Surgeon General's Call to Action in 2008 has been lower than expected given the public health impact of this disease. This scientific statement highlights future research priorities in VTE, developed by experts and a crowdsourcing survey across 16 scientific organizations. At the fundamental research level (T0), researchers need to identify pathobiologic causative mechanisms for the 50% of patients with unprovoked VTE and better understand mechanisms that differentiate hemostasis from thrombosis. At the human level (T1), new methods for diagnosing, treating, and preventing VTE will allow tailoring of diagnostic and therapeutic approaches to individuals. At the patient level (T2), research efforts are required to understand how foundational evidence impacts care of patients (eg, biomarkers). New treatments, such as catheter-based therapies, require further testing to identify which patients are most likely to experience benefit. At the practice level (T3), translating evidence into practice remains challenging. Areas of overuse and underuse will require evidence-based tools to improve care delivery. At the community and population level (T4), public awareness campaigns need thorough impact assessment. Large population-based cohort studies can elucidate the biologic and environmental underpinings of VTE and its complications. To achieve these goals, funding agencies and training programs must support a new generation of scientists and clinicians who work in multidisciplinary teams to solve the pressing public health problem of VTE.

Impact of concomitant antiplatelet therapy on the efficacy and safety of direct oral anticoagulants for acute venous thromboembolism: Systematic review and meta-analysis

BACKGROUND

Direct oral anticoagulants (DOACs) are recommended over vitamin K antagonists (VKAs) for the treatment of venous thromboembolism (VTE). Concomitant antiplatelet therapy may potentiate the antithrombotic effects of DOACs.

OBJECTIVES

We evaluated the impact of concomitant antiplatelet therapy on the efficacy and safety of DOACs.

PATIENTS/METHODS

MEDLINE, EMBASE, and Clinicaltrial.gov were searched for randomized controlled trials of DOACs for the treatment of acute VTE. The efficacy outcome was symptomatic recurrent VTE and VTE-related death; the primary safety outcome was major bleeding.

RESULTS

Six randomized controlled trials included 26 924 patients of whom 3550 (13.2%) received concomitant antiplatelet therapy, mainly aspirin (67.7%). Concomitant antiplatelet therapy did not reduce the incidence of recurrent VTE and VTE-related death with any oral anticoagulant (odds ratio [OR] 1.17; 95% confidence interval [CI], 0.92-1.48), with DOACs (OR 1.21; 95% CI, 0.86-1.71), or VKAs alone (OR 1.16; 95% CI, 0.77-1.73). Compared with no antiplatelet therapy, concomitant antiplatelet therapy was associated with a higher risk of major bleeding in patients with any oral anticoagulant (OR 1.79; 95% CI, 1.22-2.63), DOACs (OR 1.89; 95% CI, 1.04-3.44), or VKAs (OR 1.73; 95% CI, 1.16-2.59). In patients receiving concomitant antiplatelet therapy, there were no statistically significant differences in efficacy or safety outcomes with DOACs or VKAs (OR 0.99; 95% CI, 0.64-1.51, and OR 0.68; 95% CI, 0.32-1.45, respectively).

CONCLUSIONS

Concomitant use of antiplatelet therapy with oral anticoagulants does not appear to affect the risk of recurrent VTE and increases the risk of major bleeding.

Call to Action to Prevent Venous Thromboembolism in Hospitalized Patients: A Policy Statement From the American Heart Association

Venous thromboembolism (VTE) is a major preventable disease that affects hospitalized inpatients. Risk stratification and prophylactic measures have good evidence supporting their use, but multiple reasons exist that prevent full adoption, compliance, and efficacy that may underlie the persistence of VTE over the past several decades. This policy statement provides a focused review of VTE, risk scoring systems, prophylaxis, and tracking methods. From this summary, 5 major areas of policy guidance are presented that the American Heart Association believes will lead to better implementation, tracking, and prevention of VTE events. They include performing VTE risk assessment and reporting the level of VTE risk in all hospitalized patients, integrating preventable VTE as a benchmark for hospital comparison and pay-for-performance programs, supporting appropriations to improve public awareness of VTE, tracking VTE nationwide with the use of standardized definitions, and developing a centralized data steward for data tracking on VTE risk assessment, prophylaxis, and rates.

Cytokine and chemokine regulation of venous thromboembolism

Morbidity and mortality from venous thromboembolism (VTE), which refers to deep vein thrombosis and pulmonary embolism, have a substantial effect on the global burden of disease. The field of venous thrombosis research has been dramatically changed over the past 10 years with the improvement of animal models that shed some light on the interaction between inflammation and thrombosis. Important recent advances provided evidence of the implication of the innate immune system in venous thrombosis. In this review, we highlighted the cytokines and chemokines that regulate mechanisms of thrombus formation and resolution. Cytokines are pleiotropic, redundant, and multifunctional endogenous mediators orchestrating the inflammatory responses leading to thrombus formation or resolution. The use of experimental models has revealed the pro-thrombotic activity of some cytokines including interferon-γ, interleukin (IL)-6, chemokine ligand 2, IL-17A, IL-9, IL-1β, and transforming growth factor-β. Other cytokines such as IL-10, tumor necrosis factor-α, and IL-8 appear to promote thrombus resolution in late phase of venous thromboembolism. The purpose of this review is to bring together the current knowledge regarding the cytokines and chemokines that have been involved in thrombosis formation and resolution. We postulate that an imbalance between pro-thrombotic and anti-thrombotic cytokines/chemokines may be involved in the pathophysiology of VTE. However, in-depth basic and clinical research in venous thrombosis is still require to fully understand the precise mechanism of action of these cytokines.

Role of microRNAs in Venous Thromboembolism

MicroRNAs (miRNAs) are non-coding RNAs that execute their function by targeted downregulation of gene expressions. There is growing evidence from epidemiological studies and animal models suggesting that the expression level of miRNAs is dysregulated in venous thromboembolism (VTE). In this review, we summarize the current knowledge on the role of miRNAs as biomarkers for VTE and provide general insight into research exploring the modulation of miRNA activity in animal models of venous thrombosis. Up to now, published studies have yielded inconsistent results on the role of miRNAs as biomarkers for VTE with most of the reports focused on diagnostic research. The limited statistical power of the individual studies, due to the small sample sizes, may substantially contribute to the poor reproducibility among studies. In animal models, over-expression or inhibition of some miRNAs appear to influence venous thrombus formation and resolution. However, there is an important gap in knowledge on the potential role of miRNAs as therapeutic targets in VTE. Future research involving large cohorts should be designed to clarify the clinical usefulness of miRNAs as biomarkers for VTE, and animal model studies should be pursued to unravel the role of miRNAs in the pathogenesis of VTE and their potential as therapeutic targets.

ST-elevation myocardial infarction, pulmonary embolism, and cerebral ischemic stroke in a patient with critically low levels of natural anticoagulants

This clinical case report describes the simultaneous development of an acute myocardial infarction, stroke, and a massive pulmonary thromboembolism in a 44-year-old patient - a carrier of the thrombophilia gene polymorphisms: MTHFR C677T, А1298C, PAI-1 4G/5G, ITGA2 C807T. Multifocal thrombosis was probably due to the initial congenital deficiency of anticoagulants, accompanied by a decrease in antithrombin III and protein C, against the background of their critical consumption in cascade thrombosis, in combination with the carrier of polymorphisms of moderate and low thrombogenic risk. This case is unique in that there is usually a tendency toward clinical thrombosis when the level of antithrombin III is less than 70%. Such patients develop thrombosis at a younger age, and by the age of 35-40 years usually have a verified diagnosis of extremely high-risk hereditary thrombophilia. In this case, multifocal thrombosis was accompanied by critically low values of anticoagulants: antithrombin III - 3.4%, and protein C - 36.8%. The patient had suffered from epilepsy since childhood and took anticonvulsant drugs that increase the deficit of active folic acid and can lead to hyperhomocysteinemia, which in this case, against the background of an innate decrease in the activity of methyltetrahydrofolate reductase, could have aggravated the situation. <Learning objective: To focus on the possibility of the manifestation of multifocal thrombosis in congenital thrombophilia in adulthood against the background of critically low values of anticoagulants - antithrombin III and protein C.>.

An in vitro Model System for Evaluating Remote Magnetic Nanoparticle Movement and Fibrinolysis

Background

Thrombotic events continue to be a major cause of morbidity and mortality worldwide. Tissue plasminogen activator (tPA) is used for the treatment of acute ischemic stroke and other thrombotic disorders. Use of tPA is limited by its narrow therapeutic time window, hemorrhagic complications, and insufficient delivery to the location of the thrombus. Magnetic nanoparticles (MNPs) have been proposed for targeting tPA delivery. It would be advantageous to develop an improved in vitro model of clot formation, to screen thrombolytic therapies that could be enhanced by addition of MNPs, and to test magnetic drug targeting at human-sized distances.

Methods

We utilized commercially available blood and endothelial cells to construct 1/8th inch (and larger) biomimetic vascular channels in acrylic trays. MNP clusters were moved at a distance by a rotating permanent magnet and moved along the channels by surface walking. The effect of different transport media on MNP velocity was studied using video photography. MNPs with and without tPA were analyzed to determine their velocities in the channels, and their fibrinolytic effect in wells and the trays. 

Results

MNP clusters could be moved through fluids including blood, at human-sized distances, down straight or branched channels, using the rotating permanent magnet. The greatest MNP velocity was closest to the magnet: 0.76 ± 0.03 cm/sec. In serum, the average MNP velocity was 0.10 ± 0.02 cm/sec. MNPs were found to enhance tPA delivery, and cause fibrinolysis in both static and dynamic studies. Fibrinolysis was observed to occur in 85% of the dynamic MNP + tPA experiments.

Conclusion

MNPs hold great promise for use in augmenting delivery of tPA for the treatment of stroke and other thrombotic conditions. This model system facilitates side by side comparisons of MNP-facilitated drug delivery, at a human scale.

Clinical risk assessment model to predict venous thromboembolism risk after immobilization for lower-limb trauma

BACKGROUND

Patients with lower-limb trauma requiring immobilization have an increased risk of venous thromboembolism (VTE). While thromboprophylaxis for all patients seems not effective, targeted thromboprophylaxis in high risk patients may be an appropriate alternative. Therefore, we aimed to develop and validate a risk assessment model for VTE risk: the TRiP(cast) score (Thrombosis Risk Prediction following cast immobilization).

METHODS

In this prediction model study, for development, data were used from the MEGA study (case-control study into the etiology of VTE) and for validation, data from the POT-CAST trial (randomized trial on the effectiveness of thromboprophylaxis following cast immobilization) were used. Model discrimination was calculated by estimating the Area Under the Curve (AUC). For model calibration, observed and predicted risks were assessed.

FINDINGS

The TRiP(cast) score includes 14 items; one item for trauma severity (or type), one for type of immobilization and 12 items related to patients' characteristics. Validation analyses showed an AUC of 0.74 (95%CI 0.61-0.87) in the complete dataset (n = 1250) and 0.72 (95%CI 0.60-0.84) in the imputed data set (n = 1435). The calibration plot shows the degree of agreement between the observed and predicted risks (intercept 0.0016 and slope 0.933). Using a cut-off score of 7 points in the POT-CAST trial (incidence 1.6%), the sensitivity, specificity, positive and negative predictive values were 76.1%, 51.2%, 2.5%, and 99.2%, respectively.

INTERPRETATION

The TRiP(cast) score provides a helpful tool in daily clinical practice to accurately stratify patients in high versus low-risk categories in order to guide thromboprophylaxis prescribing. To accommodate implementation in clinical practice a mobile phone application has been developed.

FUNDING

ZonMW VIMP grant:17110200011.

Deep vein thrombosis cured by homeopathy: A case report

Venous thrombosis (VT) of deep vein is a life-threatening condition which may lead to sudden death as an immediate complication due to formation of thrombo-embolism. VT is associated with various risk factors such as prolonged immobilization, inflammation, and/or coagulation disorders including muscular or venous injury. Deep venous thrombosis (DVT) frequently occurs in the lower limb. Successful treatment of DVT exclusively with homeopathic remedies has rarely been recorded in peer-reviewed journals. The present case report intends to record yet another case of DVT in an old patient totally cured exclusively by the non-invasive method of treatment with micro doses of potentized homeopathic drugs selected on the basis of the totality of symptoms and individualization of the case. Since this report is based on a single case of recovery, results of more such cases are warranted to strengthen the outcome of the present study.

Pharmacological thromboprophylaxis to prevent venous thromboembolism in patients with temporary lower limb immobilization after injury: systematic review and network meta-analysis

BACKGROUND

Thromboprophylaxis has the potential to reduce venous thromboembolism (VTE) following lower limb immobilization resulting from injury.

OBJECTIVES

We aimed to estimate the effectiveness of thromboprophylaxis, compare different agents, and identify any factors associated with effectiveness.

METHODS

We undertook a systematic review and network meta-analysis (NMA) of randomized trials reporting VTE or bleeding outcomes that compared thromboprophylactic agents with each other or to no pharmacological prophylaxis, for this indication. An NMA was undertaken for each outcome or agent used, and a series of study-level network meta-regressions examined whether population characteristics, type of injury, treatment of injury, or duration of thromboprophylaxis were associated with treatment effect.

RESULTS

Data from 6857 participants across 13 randomized trials showed that, compared with no treatment, low molecular weight heparin (LMWH) reduced the risk of any VTE (odds ratio [OR]: 0.52; 95% credible interval [CrI]: 0.37-0.71), clinically detected deep vein thrombosis (DVT) (OR: 0.39; 95% CrI: 0.12-0.94) and pulmonary embolism (PE) (OR: 0.16; 95% CrI: 0.01-0.74), whereas fondaparinux reduced the risk of any VTE (OR: 0.13; 95% CrI: 0.05-0.30) and clinically detected DVT (OR: 0.10; 95% CrI: 0.01-0.86), with inconclusive results for PE (OR: 0.40; 95% CrI: 0.01-7.53).

CONCLUSIONS

Thromboprophylaxis with either fondaparinux or LMWH appears to reduce the odds of both asymptomatic and clinically detected VTE in people with temporary lower limb immobilization following an injury. Treatment effects vary by outcome and are not always conclusive. We were unable to identify any treatment effect modifiers other than thromboprophylactic agent used.

Risk Assessment of Deep Venous Thrombosis and Its Influencing Factors in Burn Patients

The objective of this study is to explore the relevant risk factors of deep venous thrombosis (DVT) in burn patients. A retrospective analysis was conducted for the medical records of 845 hospitalized burn patients from September 2012 to August 2017. Caprini thrombosis risk assessment scale (CTRAS) was employed for evaluating the risks of DVT. Based upon whether or not DVT occurred, they were divided into non-DVT group (n = 830) and DVT group (n = 15). Among 360 (42.7%) patients with high-risk Caprini scores, only 30 patients received color Doppler examination of lower limb veins, and 15 patients were diagnosed as DVT with a diagnostic rate of 1.8%. Caprini scores of non-DVT and DVT groups were 4.30 ± 2.71 and 9.87 ± 1.46 points, respectively. There was statistically significant difference (P < .05). As revealed by stepwise Logistic regression analysis, age, lower limb burn, wound infection, femoral vein catheterization, and long bedriddening time (>40 days) were independent risk factors for DVT. Burn patients are particularly prone to develop DVT. Age, wound infection, femoral vein catheterization, and long bedriddening time (>40 days) are risk factors. Aggressive preventive measures of DVT should be implemented.

Retrospective Evaluation of Venous Thromboembolism Prophylaxis in Elderly, High-Risk Trauma Patients

BACKGROUND

Venous thromboembolism (VTE) risk increases with age. Scarce data exist for patients age ≥65 y. This study evaluated VTE incidence in elderly, high-risk trauma patients receiving unfractionated heparin (UFH) or enoxaparin chemoprophylaxis.

MATERIALS AND METHODS

This retrospective, single-center, cohort study included trauma patients age ≥ 65 y with risk assessment profile (RAP) ≥ 5 who received UFH or enoxaparin chemoprophylaxis. The primary outcome was VTE incidence requiring therapeutic anticoagulation. An age-modified RAP (RAP-AM) was calculated as RAP without age distribution points. Logistic regression analyses were performed to identify independent predictors for VTE development and chemoprophylactic agent selection. Bleeding incidence compared packed red blood cells utilized.

RESULTS

A total of 1090 patients were included (UFH, n = 655; enoxaparin, n = 435). VTE occurred in 39 (3.6%) patients with no difference between groups in proximal deep vein thrombosis (2.1% versus 3.0%, P = 0.52) or pulmonary embolism (1.2% versus 1.4%, P = 0.96). Weight ≥125 kg (OR 4.12, 95% CI 1.06-16.11) and RAP-AM ≥ 5 (OR 6.52, 95% CI 2.65-16.03) were independently associated with VTE development. Increasing age (OR 1.04, 95% CI 1.03-1.06), initiation ≤ 24 h (OR 2.17, 95% CI 1.66-2.84) and creatinine clearance ≤ 30 mL/min (OR 1.61, 95% CI 1.17-2.21) were independent predictors of receiving UFH whereas increasing ISS (OR 0.97, 95% CI 0.95-0.99) was associated with receiving enoxaparin.

CONCLUSIONS

VTE incidence may be similar for high-risk, elderly trauma patients receiving UFH and enoxaparin chemoprophylaxis. Further research is necessary to determine noninferiority of UFH to enoxaparin in this patient population.

Innovative Three-Step Microwave-Promoted Synthesis of N-Propargyltetrahydroquinoline and 1,2,3-Triazole Derivatives as a Potential Factor Xa (FXa) Inhibitors: Drug Design, Synthesis, and Biological Evaluation

The coagulation cascade is the process of the conversion of soluble fibrinogen to insoluble fibrin that terminates in production of a clot. Factor Xa (FXa) is a serine protease involved in the blood coagulation cascade. Moreover, FXa plays a vital role in the enzymatic sequence which ends with the thrombus production. Thrombosis is a common causal pathology for three widespread cardiovascular syndromes: acute coronary syndrome (ACS), venous thromboembolism (VTE), and strokes. In this research a series of N-propargyltetrahydroquinoline and 1,2,3-triazole derivatives as a potential factor Xa (FXa) inhibitor were designed, synthesized, and evaluated for their FXa inhibitor activity, cytotoxicity activity and coagulation parameters. Rational design for the desired novel molecules was performed through protein-ligand complexes selection and ligand clustering. The microwave-assisted synthetic strategy of selected compounds was carried out by using Ullmann-Goldberg, N-propargylation, Mannich addition, Friedel-Crafts, and 1,3-dipolar cycloaddition type reactions under microwave irradiation. The microwave methodology proved to be an efficient way to obtain all novel compounds in high yields (73–93%). Furthermore, a thermochemical analysis, optimization and reactivity indexes such as electronic chemical potential (µ), chemical hardness (η), and electrophilicity (ω) were performed to understand the relationship between the structure and the energetic behavior of all the series. Then, in vitro analysis showed that compounds 27, 29–31, and 34 exhibited inhibitory activity against FXa and the corresponding half maximal inhibitory concentration (IC₅₀) values were calculated. Next, a cell viability assay in HEK293 and HepG2 cell lines, and coagulation parameters (anti FXa, Prothrombin time (PT), activated Partial Thromboplastin Time (aPTT)) of the most active novel molecules were performed to determine the corresponding cytotoxicity and possible action on clotting pathways. The obtained results suggest that compounds 27 and 29 inhibited FXa targeting through coagulation factors in the intrinsic and extrinsic pathways. However, compound 34 may target coagulation FXa mainly by the extrinsic and common pathway. Interestingly, the most active compounds in relation to the inhibition activity against FXa and coagulation parameters did not show toxicity at the performed coagulation assay concentrations. Finally, docking studies confirmed the preferential binding mode of N-propargyltetrahydroquinoline and 1,2,3-triazole derivatives inside the active site of FXa.

Thromboprophylaxis in lower limb immobilisation after injury (TiLLI)

Venous thromboembolic disease is a major global cause of morbidity and mortality. An estimated 10 million episodes are diagnosed yearly; over half of these episodes are provoked by hospital admission/procedures and result in significant loss of disability adjusted life years. Temporary lower limb immobilisation after injury is a significant contributor to the overall burden of venous thromboembolism (VTE). Existing evidence suggests that pharmacological prophylaxis could reduce overall VTE event rates in these patients, but the proportional reduction of symptomatic events remains unclear. Recent studies have used different pharmacological agents, dosing regimens and outcome measures. Consequently, there is wide variation in thromboprophylaxis strategies, and international guidelines continue to offer conflicting advice for clinicians. In this review, we provide a summary of recent evidence assessing both the clinical and cost effectiveness of thromboprophylaxis in patients with temporary immobilisation after injury. We also examine the evidence supporting stratified thromboprophylaxis and the validity of widely used risk assessment methods.

Factor XI(a) inhibitors for thrombosis: an updated patent review (2016-present)

Introduction: Anticoagulation without bleeding is an ideal goal in treating thrombosis, however, this goal has not been achieved. All current anticoagulants are associated with significant bleeding which limits their safe use. Genetic and pharmacological findings indicate that factor XIa is a key player in thrombosis, yet it is a relatively marginal one in hemostasis. Thus, factor XIa and its zymogen offer a unique opportunity to develop anticoagulants with low bleeding risk.Areas covered: A survey of patent literature has retrieved more than 50 patents on the discovery of novel therapeutics targeting factor XI(a) since 2016. Small molecules, monoclonal antibodies, oligonucleotides, and polypeptides have been developed to inhibit factor XI(a). Many inhibitors are in early development and few have been evaluated in clinical trials.Expert opinion: Factor XI(a) is being actively pursued as a drug target for the development of effective and safer anticoagulants. Although many patents claiming factor XI(a) inhibitors were filed prior to 2016, recent literature reveals a moderately declining trend. Nevertheless, more agents have entered different levels of clinical trials. These agents exploit diverse mechanistic strategies for inhibition. Although further development is warranted, reaching one or more of these agents to the clinic will transform the anticoagulation therapy.

Cardiorespiratory fitness and future risk of venous thromboembolism

BACKGROUND

Cardiorespiratory fitness (CRF) is a strong predictor of future arterial cardiovascular disease and premature mortality. However, there are limited data on the association between CRF and the risk of incident venous thromboembolism (VTE).

OBJECTIVES

To investigate whether estimated CRF (eCRF) was associated with the risk of incident VTE in a cohort recruited from the general population.

METHODS

Participants (n = 10 393) from the sixth survey of the Tromsø Study (2007-08) were included, and incident VTEs were recorded up to 31 December 2016. CRF was estimated in sex-specific algorithms based on age, waist circumference, resting heart rate, and self-reported physical activity. Hazard ratios (HRs) with 95% confidence intervals (CIs) of VTE according to categories of eCRF were estimated in Cox regression models adjusted for sex with age as timescale. The impact of weight status was evaluated in analyses stratified by weight category.

RESULTS

There were 176 incident VTEs during follow-up. Compared with individuals with eCRF < 85% of age-predicted, those with eCRF of 85% to 100% and >100% of age-predicted had 46% (HR 0.54; 95% CI 0.39-0.77) and 67% (HR 0.33; 95% CI 0.20-0.54) lower VTE risk, respectively. Compared with overweight/obese individuals with eCRF < 85% of age-predicted, overweight/obese individuals with eCRF ≥ 85% had 50% (HR 0.50, 95% CI 0.35-0.74) lower risk, and normal weight individuals with eCRF ≥ 85% had 55% (HR 0.45, 95% CI 0.30-0.68) lower risk.

CONCLUSIONS

Higher eCRF was associated with lower risk of incident VTE. The association was independent of weight categories, suggesting that higher eCRF may modify the association between obesity and VTE.

Rosuvastatin use improves measures of coagulation in patients with venous thrombosis

Aims

Observational studies indicate that statins reduce the risk of recurrent venous thrombosis (VT). However, trials have not been performed and the mechanism is unknown. We aimed to determine whether statin therapy improves the coagulation profile in patients with prior VT.

Methods and results

Randomized clinical trial (NCT01613794). Patients were randomized to rosuvastatin 20 mg/day for 4 weeks or no intervention. Blood was drawn at baseline and at end of study. The primary outcome was factor (F) VIII:C. In total, five coagulation factors were measured: FVIII:C, von Willebrand factor:Ag, FVII:C, FXI:C, and D-dimer. Among 247 randomized participants, mean age was 58 years, 62% were women and 49% had unprovoked VT. For all tested coagulation factors, mean levels were clearly decreased at end of study in rosuvastatin users, whereas they hardly differed in non-statin users. Results were most consistent for FVIII:C where mean FVIII:C levels were 7.2 IU/dL [95% CI (confidence interval) 2.9-11.5] lower in rosuvastatin users, while among non-users, no change in FVIII:C was observed (mean difference -0.1; 95% CI -3.0 to 2.9). The mean age and sex adjusted difference in FVIII:C change was -6.7 IU/dL (95% CI -12.0 to -1.4) in rosuvastatin users vs. non-users. Subgroup analyses revealed that the decrease in coagulation factors by rosuvastatin was more pronounced in participants with unprovoked VT and in those with cardiovascular risk factors.

Conclusion

Rosuvastatin 20 mg/day substantially improved the coagulation profile among patients with prior VT. These results suggest that statin therapy might be beneficial in patients at risk of recurrent VT.

Interaction between Traditional Chinese Medicine and Anticoagulant/Antiplatelet Drugs

Background:

Traditional Chinese medicine (TCM) has been used for medical purposes since the ancient time and has gradually gained recognition worldwide. Nowadays, patients with thrombus presiding to anticoagulant/ antiplatelet drugs prefer taking TCM. However, an increasing number of studies on herb–drug interactions have been shown. Nevertheless, findings are frequently conflicting and vague. In this review, we discuss the herb–drug interactions between TCM and anticoagulant/antiplatelet drugs to provide guidance on concomitant ingestion with anticoagulant/antiplatelet drugs.

Methods:

We undertook a structured search of medicine and drug databases for peer-reviewed literature using focused review questions.

Results:

Danshen, Ginkgo, Ginger, H. Perforatum, SMY and Puerarin injection had directional regulation effects on the efficacy of anticoagulant drugs by altering the CYPs, pharmacokinetic indexs and hemorheological parameters. H. Perforatum inhibited the efficacy of Clopidogrel by enhancing the CYP3A4 activity and Ginkgo increased the efficacy of Ticlopidine. Additionally, Renshen, the formulae except SMY and injections except Puerarin injection could increase or decrease the efficacy of anticoagulant/antiplatelet drugs via regulating the CYPs, platelet aggregation, hemorheological parameters and others.

Conclusion:

Some cases have reported that TCMs may increase the bleeding risk or has no effect on coagulation when anticoagulant/antiplatelet drugs are concurrently used. However, pharmacokinetic studies have presented either consistent or slightly varying results. So it is difficult to ascertain whether the concurrent use of TCM may increase or reduce the pharmacologic effects of anticoagulant/antiplatelet drugs with adverse reactions. Therefore, herb–drug interactions of TCM and anticoagulant/antiplatelet drugs should be further explored and defined.

Anticoagulation therapy patterns for acute treatment of venous thromboembolism in GARFIELD-VTE patients

BACKGROUND

Parenteral anticoagulants and vitamin K antagonists (VKAs) have constituted the cornerstone of venous thromboembolism (VTE) treatment. Meanwhile, direct oral anticoagulants (DOACs) provide physicians with an alternative. The Global Anticoagulant Registry in the FIELD (GARFIELD)-VTE observes real-world treatment practices.

OBJECTIVES

Describe initial anticoagulation (AC) treatment patterns in VTE patients who received parenteral AC, VKAs, and/or DOACs within ±30 days of diagnosis.

METHODS

VTE patients were categorized into parenteral AC only, parenteral AC with transition to VKA, VKA only, parenteral AC with transition to DOAC, and DOAC only.

RESULTS

A total of 9647 patients were initiated on AC treatment alone. 4781 (49.6%) patients received DOACs ± parenteral ACs; 3187 (33.0%), VKA ± parenteral ACs; and 1679 (17.4%) parenteral ACs alone. Rivaroxaban was the most frequently used DOAC (79.4%). DOACs were more frequently used in North America/Australia (58.1%), Europe (52.2%), and Asia (47.6%) than in Latin America (29.7%) and the Middle East/South Africa (32.5%). In patients with suspected VTE, most received parenteral AC monotherapy (67.7%). Patients with deep vein thrombosis were more likely to receive DOACs alone than those with pulmonary embolism with or without deep vein thrombosis (36.2% vs 25.9%). Active cancer patients received parenteral AC alone (58.9%), with 25.5% receiving DOAC ± parenteral AC and 12.8% parenteral AC and VKA. A total of 46.5% of pregnant patients received parenteral AC monotherapy, 34.0% were treated with VKA ± parenteral AC, and 19.5% received a DOAC (± parenteral AC).

CONCLUSION

AC treatment patterns vary by patient population, geographic region and site of VTE. Guidelines for AC therapy are not always adhered to.

Structure based design of macrocyclic factor XIa inhibitors: Discovery of cyclic P1 linker moieties with improved oral bioavailability

This manuscript describes the discovery of a series of macrocyclic inhibitors of FXIa with oral bioavailability. Assisted by structure based drug design and ligand bound X-ray crystal structures, the group linking the P1 moiety to the macrocyclic core was modified with the goal of reducing H-bond donors to improve pharmacokinetic performance versus 9. This effort resulted in the discovery of several cyclic P1 linkers, exemplified by 10, that are constrained mimics of the bioactive conformation displayed by the acrylamide linker of 9. These cyclic P1 linkers demonstrated enhanced bioavailability and improved potency.

LIM-only protein FHL2 attenuates vascular tissue factor activity, inhibits thrombus formation in mice and FHL2 genetic variation associates with human venous thrombosis

Bleeding disorders and thrombotic complications are major causes of morbidity and mortality with many cases being unexplained. Thrombus formation involves aberrant expression and activation of tissue factor (TF) in vascular endothelial and smooth muscle cells. Here, we sought to identify factors that modulate TF gene expression and activity in these vascular cells. The LIM-only protein FHL2 is a scaffolding protein that modulates signal transduction pathways with crucial functions in endothelial and smooth muscle cells. However, the role of FHL2 in TF regulation and thrombosis remains unexplored. Using a murine model of venous thrombosis in mesenteric vessels, we demonstrated that FHL2 deficiency results in exacerbated thrombus formation. Gain- and loss-of-function experiments revealed that FHL2 represses TF expression in endothelial and smooth muscle cells through inhibition of the transcription factors nuclear factor κB and activating protein-1. Furthermore, we observed that FHL2 interacts with the cytoplasmic tail of TF. In line with our in vivo observations, FHL2 decreases TF activity in endothelial and smooth muscle cells whereas FHL2 knockdown or deficiency results in enhanced TF activity. Finally, the FHL2 single nucleotide polymorphism rs4851770 was associated with the risk of venous thrombosis in a large population of venous thrombosis cases and control subjects from 12 studies (INVENT consortium). Altogether, our results highlight functional involvement of FHL2 in TF-mediated coagulation and identify FHL2 as a novel gene associated with venous thrombosis in humans.

Humanized GPIbα-von Willebrand factor interaction in the mouse

The interaction of platelet glycoprotein Ibα (GPIbα) with von Willebrand factor (VWF) initiates hemostasis after vascular injury and also contributes to pathological thrombosis. GPIbα binding to the VWF A1 domain (VWFA1) is a target for antithrombotic intervention, but attempts to develop pharmacologic inhibitors have been hindered by the lack of animal models because of the species specificity of the interaction. To address this problem, we generated a knockin mouse with Vwf exon 28-encoding domains A1 and A2 replaced by the human homolog (VWF^h28). VWF^h28 mice (M1HA) were crossbred with a transgenic mouse strain expressing human GPIbα on platelets (mGPIbα^null;hGPIbα^Tg; H1MA) to generate a new strain (H1HA) with humanized GPIbα-VWFA1 binding. Plasma VWF levels in the latter 3 strains were similar to those of wild-type mice (M1MA). Compared with the strains that had homospecific GPIbα-VWF pairing (M1MA and H1HA), M1HA mice of those with heterospecific pairing had a markedly greater prolongation of tail bleeding time and attenuation of thrombogenesis after injury to the carotid artery than H1MA mice. Measurements of GPIbα-VWFA1 binding affinity by surface plasmon resonance agreed with the extent of observed functional defects. Ristocetin-induced platelet aggregation was similar in H1HA mouse and human platelet-rich plasma, and it was comparably inhibited by monoclonal antibody NMC-4, which is known to block human GPIbα-VWFA1 binding, which also inhibited FeCl₃-induced mouse carotid artery thrombosis. Thus, the H1HA mouse strain is a fully humanized model of platelet GPIbα-VWFA1 binding that provides mechanistic and pharmacologic information relevant to human hemostatic and thrombotic disorders.

miR-21 induces endothelial progenitor cells proliferation and angiogenesis via targeting FASLG and is a potential prognostic marker in deep venous thrombosis

BACKGROUND

Deep venous thrombosis (DVT) of lower extremities is a common thrombotic disease, occurring either in isolation or as a complication of other diseases or procedures. MiR-21 is one of important microRNAs which play critical role in various cellular function. This study aim to determine the effect of miR-21 on endothelial progenitor cells (EPCs) and its role in predicting prognosis of DVT.

METHODS

EPCs was isolated from DVT models and control subjects. miR-21 expression was confirmed by RT-PCR. Potential target mRNA was predicted by bioinformatics analysis. EPCs biological functions were examined by CCK-8 and tube formation assay. Besides, miR-21 expression was determined in DVT patients to investigate the correlation between miR-21 expression and prognosis of DVT. Cox proportional hazard regression analyses were also performed to reveal the risk factors associated with prognosis.

RESULTS

Here, we found miR-21 was downregulated in EPCs of DVT model rats. Increased miR-21 expression promoted proliferation and angiogenesis of EPCs. Moreover, we demonstrated that FASLG was a target of miR-21 and revealed that FASLG knockdown inhibited function of EPCs. Upregulation of miR-21 led to thrombus resolution in a rat model of venous thrombosis. In addition, lower expression level of miR-21 in DVT patients was associated with an increase of recurrent DVT and post thrombotic syndrome (PTS). Furthermore, Cox proportional hazard regression analyses demonstrated miR-21 expression level as an independent predictor of recurrence of DVT.

CONCLUSIONS

Our data revealed a role of miR-21 in regulating biological function of EPCs and could be a predictor for recurrent DVT or PTS.

Identification of Chinese Hospitalized Patients' Risk Profile for Venous Thromboembolism (DissolVE1): A Study Protocol of a Non-Interventional Registry Study

INTRODUCTION

Venous thromboembolism (VTE) is a frequent cause of hospitalization, mortality, and long-term adverse consequence among medical and surgical inpatients. The current study is performed to identify the prophylaxis of patients with VTE risk within the 6 weeks prior to the diagnosis of VTE, and the treatment pattern during 3 months after VTE diagnosis in Chinese patients hospitalized for surgeries or medical illness.

METHODS

This multicenter, non-interventional, observational registry plans to enroll 1200 patients from 40 centers in China. The study will retrospectively collect data from patients' hospitalization record within 6 weeks of VTE diagnosis and prospectively follow-up patients for 3 months (in four visits). The primary outcome is to determine the percentage of patients receiving adequate prophylaxis in patients hospitalized within 6 weeks before VTE diagnosis and treatment pattern within 3 months after VTE diagnosis. Important secondary endpoints include determining patients with risk of VTE in the hospital setting, risk factors for VTE, and cost analysis of VTE treatment.

EXPECTED OUTCOMES

The findings will determine the characteristics of VTE, its treatment practices, cost of treatment, and quality of life in patients; this information may help in building diagnostic and prophylaxis strategies for VTE in China.

TRIAL REGISTRATION

The study is registered in the Venous Thromboembolism Registry in China with study number DIREGL07581.

FUNDING

Sanofi China.

Analysis of the Association Between MicroRNA Biogenesis Gene Polymorphisms and Venous Thromboembolism in Koreans

Venous thromboembolism (VTE) involves the formation of a blood clot, typically in the deep veins of the leg or arm (deep vein thrombosis), which then travels via the circulatory system and ultimately lodges in the lungs, resulting in pulmonary embolism. A number of microRNAs (miRNAs) are well-known regulators of thrombosis and thrombolysis, and mutations in miRNA biogenesis genes, such as DICER1, DROSHA have been implicated in miRNA synthesis and function. We investigated the genetic association between polymorphisms in four miRNA biogenesis genes, DICER1 rs3742330A > G, DROSHA rs10719T > C, RAN rs14035C > T and XPO5 rs11077A > C, and VTE in 503 Koreans: 300 controls and 203 patients. Genotyping was assessed with polymerase chain reaction-restriction fragment length polymorphism assays. We detected associations between polymorphisms in RAN and XPO5 and VTE prevalence (RAN rs14035CC + CT versus TT: p = 0.018; XPO5 rs11077AA + AC versus CC: p < 0.001). Analysis of allele combinations of all four polymorphisms (DICER1, DROSHA, RAN, XPO5) revealed that A-T-T-A was associated with decreased VTE prevalence (p = 0.0002), and A-T-C-C was associated with increased VTE prevalence (p = 0.027). Moreover, in subjects with provoked VTE, the DROSHA rs10719T > C, polymorphism was associated with increased disease prevalence (TT versus TC + CC: p < 0.039). Our study demonstrates that RAN and XPO5 polymorphisms are associated with risk for VTE in Korean subjects.

Implementation of an acute DVT ambulatory care pathway in a large urban centre: current challenges and future opportunities

Background

Ambulatory management of isolated acute deep venous thrombosis (DVT) is the recommended standard of care in selected populations. However, in practice a significant number of patients continue to be managed as in-patients.

Objectives

In this study we aimed to evaluate acute DVT treatment pathways in our emergency department (ED) in practice and to identify barriers to outpatient management.

Methods

This study was a cross-sectional analysis of prospectively collected data pertaining to consecutive patients presenting to the ED of a large, city center, academic teaching hospital over a 46 week period who were diagnosed with DVT.

Results

Implementation of an outpatient care pathway led to the majority of patients presenting with DVT in our institution being treated without hospital admission. Forty percent (31/78) of patients with DVT were treated with a direct oral anticoagulant (DOAC) as an outpatient in line with international best practice guidelines.

Conclusion

The study provides a clear picture of the clinical profile and management of patients in clinical practice. Due to the lack of resources and supported infrastructure it is difficult to effectively implement outpatient venous thromboembolism (VTE) management to its full potential. Directing resources towards strategies which facilitate outpatient DVT treatment among vulnerable patient groups could represent a means of reducing hospital admissions for DVT in urban centers. Our study highlights the success and clinical limitations of the outpatient treatment model, which should become standard as part of wider VTE care.

RAVS Study: One Indian Single Center Analysis of Patients with VTE

Objective: Venous thromboembolism (VTE) includes deep vein thrombosis (DVT) and pulmonary embolism (PE). VTE affects all races, age groups, and genders. The objective of this registry was to analyze the patient characteristics, clinical outcomes, management strategies, and temporal trends in VTE at a single center.

Materials and Methods: Consecutive medical records of inpatients between January 2007 and March 2018, meeting the inclusion criteria (confirmed diagnosis of DVT by Doppler ultrasound scan and/or PE by chest computed tomography) were identified and collected. A total of 1,024 patients were reviewed.

Results: Eight hundred and twelve patients with VTE were enrolled into the study; 37.4% were referrals from outside hospitals, 33.1% of the total patients had no risk factors, hence classified as unprovoked VTE and the rest of the patients had single or multiple risk factors which may have provoked the VTE, 68.8% presented with swelling and pain, and 88.5% had proximal DVT.

Conclusion: VTE is no longer a rare phenomenon in the Indian population, as believed earlier. The knowledge of VTE, prophylaxis, and treatment strategies is minimal among small institutes, nursing homes, and among general practitioners who are not affiliated with teaching institutes. Therefore, educating primary care physicians/surgeons on VTE is paramount, as this would reduce the incidence of VTE in India as well as associated morbidity and mortality rates.

Venous thromboembolism incidence in the Ireland east hospital group: a retrospective 22-month observational study

OBJECTIVES

To determine the incidence of venous thromboembolism (VTE) and the incidence of hospital-acquired VTE (HA-VTE) arising within the population served by the Ireland East Hospital Group (IEHG).

DESIGN

/home/user/Documents/Sathish Kumar G/RFO/June/21-06-2019/bmjopen_iss_9_7_20190621_1/ A retrospective observational study was conducted using hospital discharge data obtained from the hospital inpatient enquiry data reporting system. In this system, VTE events recorded as 'primary diagnosis' represented the reason for initial hospital admission, whereas VTE recorded as a 'secondary diagnosis' occurred following admission and were therefore used as an approximation of HA-VTE. These data were used to estimate the overall incidence of VTE and the proportion of these events which were hospital-acquired.

SETTING

The IEHG is the largest hospital group in the Irish healthcare system and serves a population of over 1 million individuals.

PARTICIPANTS

Data were generated from records pertaining to the 2727 patient admission episodes where a diagnosis of VTE was made during the 22-month study period.

RESULTS

During the study period, 2727 VTE events were recorded within the IEHG (which serves a population of 1 036 279) corresponding to an incidence of 1.44 (95% CI 1.36 to 1.51) per 1000 per annum. 1273 (47%) of VTE events were recorded as secondary VTE. The incidence of VTE was highest among individuals over 85 years of age (16.03 per 1000;95% CI 12.81 to 19.26) and was more common following emergency hospital admission.

CONCLUSION

These data suggest that HA-VTE accounts for at least 47% of all VTE events arising within a hospital group serving a population of over 1 million individuals within the Ireland. Given that HA-VTE is a well-recognised source of (potentially preventable) hospital deaths, these findings provide a compelling argument for prioritising strategies directed at reducing the risk of VTE among hospital patients served by the IEHG and within the Ireland as a whole.

An Efficient Modular One-Pot Synthesis of Heparin-Based Anticoagulant Idraparinux

Idraparinux is a fully O-sulfated α-methyl glycoside of heparin pentasaccharide motif known to interact with the antithrombin III domain and act as anticoagulant. The current most effective synthesis of Idraparinux is complicated and nonstereoselective, requiring numerous stepwise procedures with low yields. We report here an efficient modular one-pot synthesis of Idraparinux involving the use of a glycosyl phosphate with 6- O- tert-butyl diphenyl silyl group and a d-glucuronic acid-containing disaccharide thioglycoside with 6- O-acetyl group as donor building blocks for the α-directing one-pot glycosylations with an l-iduronic acid-containing disaccharide acceptor building block. The uronic acid was incorporated in a disaccharide module used in the one-pot synthesis to avoid the complicated late-stage installation of these acidic sugars. The one-pot synthesis of Idraparinux demonstrated here is an effective strategy and should be applicable to the modular assembly of other heparan sulfates with regiodefined sulfation pattern for functional study.

Analysis of recanalization of deep venous thrombosis: a comparative study of patients treated with warfarin vs. rivaroxaban

BACKGROUND

Deep venous thrombosis (DVT) strikes around ten million people worldwide every year and is associated with major complications including pulmonary embolism and post-thrombotic syndrome. Anticoagulation is the standard treatment, with administration of heparins, vitamin K antagonists, fondaparinux, or, more recently, direct oral anticoagulants (DOACs). Anticoagulants reduce thrombus progression and facilitate natural thrombolytic mechanisms, leading to a phenomenon known as recanalization, which can occur in varying degrees and over variable periods of time, under influence from many different factors, including the type of anticoagulation employed.

OBJECTIVES

To evaluate the degree of recanalization and the time taken, by analysis of color Doppler ultrasonography (CDU) reports from patients with DVT treated with DOACs or with heparin + warfarin.

METHODS

A retrospective analysis was conducted of demographic data and CDU reports from patients with DVT who had been treated from January 2009 to December 2016. These patients were classified into two groups, according to the treatment given: Group I (heparin + warfarin): 26 patients; or Group II (rivaroxaban): 51 patients. The primary outcomes assessed were degree of recanalization and time taken.

RESULTS

Recanalization rates at 30, 90, and 180 days were 10%, 52.5%, and 78.9%, respectively, in Group I, and 55.3%, 83.5%, and 92.4%, respectively, in Group II, with statistically significant difference (p = 0.041).

CONCLUSIONS

Both treatments led to recanalization. Recanalization occurred earlier among patients treated with rivaroxaban.

Fibrinolysis and Inflammation in Venous Thrombus Resolution

Clinical observations and accumulating laboratory evidence support a complex interplay between coagulation, inflammation, innate immunity and fibrinolysis in venous thromboembolism (VTE). VTE, which includes deep vein thrombosis (DVT) and pulmonary embolism (PE), and the subsequent complications of post-thrombotic syndrome (PTS), are significant causes of morbidity and mortality in patients. Clinical risk factors for VTE include cancer, major trauma, surgery, sepsis, inflammatory bowel disease, paralysis, prolonged periods of immobility, and aging. Abnormalities in venous blood flow or stasis initiates the activation of endothelial cells, and in concert with platelets, neutrophils and monocytes, propagates VTE in an intact vein. In addition, inflammatory cells play crucial roles in thrombus recanalization and restoration of blood flow via fibrinolysis and vascular remodeling. Faster resolution of the thrombus is key for improved disease prognosis. While in the clinical setting, anticoagulation therapy is successful in preventing propagation of venous thrombi, current therapies are not designed to inhibit inflammation, which can lead to the development of PTS. Animal models of DVT have provided many insights into the molecular and cellular mechanisms involved in the formation, propagation, and resolution of venous thrombi as well as the roles of key components of the fibrinolytic system in these processes. Here, we review the recent advances in our understanding of fibrinolysis and inflammation in the resolution of VTE.

Environmental Specification of Pluripotent Stem Cell Derived Endothelial Cells Toward Arterial and Venous Subtypes

Endothelial cells (ECs) are required for a multitude of cardiovascular clinical applications, such as revascularization of ischemic tissues or endothelialization of tissue engineered grafts. Patient derived primary ECs are limited in number, have donor variabilities and their in vitro phenotypes and functions can deteriorate over time. This necessitates the exploration of alternative EC sources. Although there has been a recent surge in the use of pluripotent stem cell derived endothelial cells (PSC-ECs) for various cardiovascular clinical applications, current differentiation protocols yield a heterogeneous EC population, where their specification into arterial or venous subtypes is undefined. Since arterial and venous ECs are phenotypically and functionally different, inappropriate matching of exogenous ECs to host sites can potentially affect clinical efficacy, as exemplified by venous graft mismatch when placed into an arterial environment. Therefore, there is a need to design and employ environmental cues that can effectively modulate PSC-ECs into a more homogeneous arterial or venous phenotype for better adaptation to the host environment, which will in turn contribute to better application efficacy. In this review, we will first give an overview of the developmental and functional differences between arterial and venous ECs. This provides the foundation for our subsequent discussion on the different bioengineering strategies that have been investigated to varying extent in providing biochemical and biophysical environmental cues to mature PSC-ECs into arterial or venous subtypes. The ability to efficiently leverage on a combination of biochemical and biophysical environmental cues to modulate intrinsic arterio-venous specification programs in ECs will greatly facilitate future translational applications of PSC-ECs. Since the development and maintenance of arterial and venous ECs in vivo occur in disparate physio-chemical microenvironments, it is conceivable that the application of these environmental factors in customized combinations or magnitudes can be used to selectively mature PSC-ECs into an arterial or venous subtype.

Physical activity and risk of recurrence and mortality after incident venous thromboembolism

BACKGROUND

Limited data exist on the relationship between physical activity and major complications after incident venous thromboembolism (VTE).

OBJECTIVES

To investigate whether physical activity was associated with risk of recurrence and mortality in patients with VTE recruited from the general population.

METHODS

Patients with incident VTE (n = 786) derived from the Tromsø Study surveys 4-6 (1994-1995, 2001-2002, and 2007-2008) were included, and data on physical activity were dichotomized according to the activity level reported in the survey preceding the incident VTE (inactive: <1 hour per week, active: ≥1 hour per week). Recurrent VTE and all-cause mortality were registered up to December 31, 2015. Hazard ratios (HRs) for recurrence and all-cause mortality were calculated using Cox regression models with the inactive group as reference.

RESULTS

There were 139 recurrences and 395 deaths during follow-up. Physical activity was not associated with the risk of recurrence in men (HR model 2: 1.48, 95% confidence interval [CI] 0.83-2.65) or in women (HR model 2: 0.95, 95% CI 0.52-1.74). In contrast, physical activity was associated with a 28% lower risk of mortality during 10 years of follow up (HR model 3: 0.72, 95% CI 0.57-0.91). The inverse association was stronger in patients with a first deep vein thrombosis ( HR model 2: 0.59, 95% CI 0.44-0.79) than a pulmonary embolism (HR model 3: 0.87, 95% CI 0.61-1.26).

CONCLUSION

Our results suggest that habitual physical activity prior to incident VTE does not influence the risk of recurrence. In contrast, active individuals were at lower risk of mortality, particularly following deep vein thrombosis.

[Modern treatment of deep vein thrombosis and pulmonary embolism]

Virchow's triad has been known for a 100 years. The development of therapeutic possibilities during this time was enormous. Today anticoagulant therapy is much more differentiated. Four new oral substances have replaced the traditional treatment with vitamin K antagonists in angiology. A standardized dosage is available. The monitoring of the coagulation parameters is no longer necessary, but it is important to monitor renal function. Direct oral anticoagulants are approved for the treatment of venous thrombosis and pulmonary embolism, but not during pregnancy or in children. Severe bleeding complications, especially intracerebral bleeding, are less common. The incidence of venous thromboembolism is still high. Obesity and cancer are of particular importance. The "therapeutic pact" with the patient requires that physicians master the art of "talking medicine".