Mechanistic View of Risk Factors for Venous Thromboembolism

Cancer progression and tumor hypercoagulability: a platelet perspective

Venous thromboembolism, which is common in cancer patients and accompanies or even precedes malignant tumors, is known as cancer-related thrombosis and is an important cause of cancer- associated death. At present, the exact etiology of the elevated incidence of venous thrombosis in cancer patients remains elusive. Platelets play a crucial role in blood coagulation, which is intimately linked to the development of arterial thrombosis. Additionally, platelets contribute to tumor progression and facilitate immune evasion by tumors. Tumor cells can interact with the coagulation system through various mechanisms, such as producing hemostatic proteins, activating platelets, and directly adhering to normal cells. The relationship between platelets and malignant tumors is also significant. In this review article, we will explore these connections.

Double bad luck: pulmonary embolism and vaginal bleeding - a case report

BACKGROUND

Pulmonary embolism is a common and potentially fatal condition. Exogenous estrogens in contraceptives are associated with an increased risk of venous thrombo-embolism. However, discontinuation of a combined oral contraceptive can lead to severe withdrawal bleeding in an anticoagulated patient.

CASE PRESENTATION

We report a case of a 47-year-old female who presented to the emergency room with a two-day history of worsening shortness of breath and chest pain. Her chronic medication included a combined oral contraceptive pill. Transthoracic echocardiogram showed pulmonary hypertension and right ventricular dilatation. Computerized tomography scan revealed bilateral pulmonary embolism. She received thrombolysis with alteplase and was started on rivaroxaban. Five days after discharge, however, she was readmitted with severe vaginal bleeding.

DISCUSSION AND CONCLUSION

We describe a case of submassive pulmonary embolism, treated with thrombolysis and anticoagulation, who developed severe vaginal bleeding after stopping the contraceptive pill. This case highlights the importance of detailed menstrual history taking when initiating anticoagulation in women. Discontinuation of oral contraceptives, while important in reducing the risk of recurrent thrombosis, could be postponed until the end of the recommended course of anticoagulation and until a safe alternative form of contraception has been established, if required.

Factors Associated with Venous Thromboembolism Development in Patients with Traumatic Brain Injury

BACKGROUND

Venous thromboembolic (VTE) events are a major concern in trauma and intensive care, with the prothrombotic state caused by traumatic brain injury (TBI) increasing the risk in affected patients. We sought to identify critical demographic and clinical variables and determine their influence on subsequent VTE development in patients with TBI.

METHODS

This was a cross-sectional study with data retrospectively collected from 818 patients with TBI admitted to a level I trauma center in 2015-2020 and placed on VTE prophylaxis.

RESULTS

The overall VTE incidence was 9.1% (7.6% deep vein thrombosis, 3.2% pulmonary embolism, 1.7% both). The median time to diagnosis was 7 days (interquartile range 4-11) for deep vein thrombosis and 5 days (interquartile range 3-12) for pulmonary embolism. Compared with those who did not develop VTE, patients who developed VTE were younger (44 vs. 54 years, p = 0.02), had more severe injury (Glasgow Coma Scale 7.5 vs. 14, p = 0.002, Injury Severity Score 27 vs. 21, p < 0.001), were more likely to have experienced polytrauma (55.4% vs. 34.0%, p < 0.001), more often required neurosurgical intervention (45.9% vs. 30.5%, p = 0.007), more frequently missed ≥ 1 dose of VTE prophylaxis (39.2% vs. 28.4%, p = 0.04), and were more likely to have had a history of VTE (14.9% vs. 6.5%, p = 0.008). Univariate analysis demonstrated that 4-6 total missed doses predicted the highest VTE risk (odds ratio 4.08, 95% confidence interval 1.53-10.86, p = 0.005).

CONCLUSIONS

Our study highlights patient-specific factors that are associated with VTE development in a cohort of patients with TBI. Although many of these are unmodifiable patient characteristics, a threshold of four missed doses of chemoprophylaxis may be particularly important in this critical patient population because it can be controlled by the care team. Development of intrainstitutional protocols and tools within the electronic medical record to avoid missed doses, particularly among patients who require operative interventions, may result in decreasing the likelihood of future VTE formation.

Venous Thromboembolism: Review of Clinical Challenges, Biology, Assessment, Treatment, and Modeling

Venous thromboembolism (VTE) is a massive clinical challenge, annually affecting millions of patients globally. VTE is a particularly consequential pathology, as incidence is correlated with extremely common risk factors, and a large cohort of patients experience recurrent VTE after initial intervention. Altered hemodynamics, hypercoagulability, and damaged vascular tissue cause deep-vein thrombosis and pulmonary embolism, the two permutations of VTE. Venous valves have been identified as likely locations for initial blood clot formation, but the exact pathway by which thrombosis occurs in this environment is not entirely clear. Several risk factors are known to increase the likelihood of VTE, particularly those that increase inflammation and coagulability, increase venous resistance, and damage the endothelial lining. While these risk factors are useful as predictive tools, VTE diagnosis prior to presentation of outward symptoms is difficult, chiefly due to challenges in successfully imaging deep-vein thrombi. Clinically, VTE can be managed by anticoagulants or mechanical intervention. Recently, direct oral anticoagulants and catheter-directed thrombolysis have emerged as leading tools in resolution of venous thrombosis. While a satisfactory VTE model has yet to be developed, recent strides have been made in advancing in silico models of venous hemodynamics, hemorheology, fluid-structure interaction, and clot growth. These models are often guided by imaging-informed boundary conditions or inspired by benchtop animal models. These gaps in knowledge are critical targets to address necessary improvements in prediction and diagnosis, clinical management, and VTE experimental and computational models.

Fibrinolysis biomarker, thrombin, and activated protein C level alterations after coagulation activation depend on type of thrombophilia and clinical phenotype

Background

Recently, we have shown alterations in the anticoagulant response to recombinant activated factor VII (rFVIIa)-induced coagulation activation in patients with thrombophilia.

Objectives

This study aimed to extend this in vivo model to fibrinolysis biomarkers.

Methods

This interventional in vivo study included 56 patients with thrombophilia and previous venous thromboembolism (VTE+), 38 without VTE (VTE-), and 35 healthy controls. Plasma levels of D-dimer, plasmin-α2-antiplasmin (PAP) complex, and plasminogen activator inhibitor-1 (PAI-1) were monitored for over 8 hours after rFVIIa infusion (15 μg/kg) along with thrombin markers and activated protein C (APC).

Results

Throughout cohorts, median PAP increased by 40% to 52% (P < 3.9 × 10-10) and PAI-1 decreased by 59% to 79% (P < 3.5 × 10-8). In contrast to thrombin-antithrombin (TAT) complex, which also increased temporarily (44% to 115%, P < 3.6 × 10-6), changes in PAP and PAI-1 did not reverse during the observation period. The area under the measurement-time curves (AUCs) of PAP and TAT, which are measures of plasmin and thrombin formation, respectively, were each greater in the VTE+ cohort than in healthy controls (median PAP-AUC = 0.48 vs 0.27 ng·h/L [P = .003], TAT-AUC = 0.12 vs 0.03 nmol·h/L [P = 2.5 × 10-4]) and were correlated with one another (r = 0.554). As evidenced by the respective AUCs, asymptomatic factor (F)V Leiden carriers showed less PAP formation (0.22 vs 0.41 ng·h/L, P = 9 × 10-4), more pronounced PAI-1 decline (0.10 vs 0.18 ng·h/L, P = .01), and increased APC formation (28.7 vs 15.4 pmol·h/L, P = .02) than those within the VTE+ group (n = 19 each).

Conclusion

rFVIIa-induced thrombin formation is associated with fibrinolysis parameter changes outlasting the concomitant anticoagulant response. Both correlate with thrombosis history in FV Leiden and might help explain its variable clinical expressivity.

Recent Advances on the Molecular Mechanism and Clinical Trials of Venous Thromboembolism

Venous thromboembolism is a condition that includes deep vein thrombosis and pulmonary embolism. It is the third most common cardiovascular disease behind acute coronary heart disease and stroke. Over the past few years, growing research suggests that venous thrombosis is also related to the immune system and inflammatory factors have been confirmed to be involved in venous thrombosis. The role of inflammation and inflammation-related biomarkers in cerebrovascular thrombotic disease is the subject of ongoing debate. P-selectin leads to platelet-monocyte aggregation and stimulates vascular inflammation and thrombosis. The dysregulation of miRNAs has also been reported in venous thrombosis, suggesting the involvement of miRNAs in the progression of venous thrombosis. Plasminogen activator inhibitor-1 (PAI-1) is a crucial component of the plasminogen-plasmin system, and elevated levels of PAI-1 in conjunction with advanced age are significant risk factors for thrombosis. In addition, it has been showed that one of the ways that neutrophils promote venous thrombosis is the formation of neutrophil extracellular traps (NETs). In recent years, the role of extracellular vesicles (EVs) in the occurrence and development of VTE has been continuously revealed. With the advancement of research technology, the complex regulatory role of EVs on the coagulation process has been gradually discovered. However, our understanding of the causes and consequences of these changes in venous thrombosis is still limited. Therefore, we review our current understanding the molecular mechanisms of venous thrombosis and the related clinical trials, which is crucial for the future treatment of venous thrombosis.

Venous thromboembolism among physically active young adult females

Background

Young adult females are at risk of venous thromboembolism (VTE) due to various acquired and transient factors. In recent years, a growing number of females have engaged in strenuous physical activity, but its role as a risk factor for VTE is uncertain.

Objectives

To determine the incidence of VTE in young adult females engaged in strenuous physical activity.

Methods

A large national cohort of female individuals enlisted in the Israeli Defense Forces between 2012 and 2019 was analyzed. The study group consisted of participants undergoing strenuous physical training during their military service, while the control group maintained regular activity levels. We compared the incidence of VTE between the groups and adjusted for potential risk factors using a multivariate Cox analysis.

Results

The cohort included 160,718 female individuals aged 18 to 21years, of whom 11,745 engaged in strenuous physical activity and 148,973 served as controls. During a mean follow-up of 1.7 years, VTE occurred in 5 individuals (0.04%) in the strenuous activity group and 47 individuals (0.03%) in the control group. The incidence per 10,000 person-years was 2.41 (95% CI, 0.78-5.62) for the strenuous activity group and 1.82 (95% CI, 1.34-2.42) for the controls. Strenuous activity did not increase the risk for VTE in univariate or multivariate regression, with a hazard ratio (HR) of 1.27 (95% CI, 0.49-4.22). Use of oral contraceptives was the only significant risk factor, demonstrating dose effect; HR 1.95 (95% CI, 1.06-3.57) for low dose and HR 3.62 (95% CI, 1.40-9.37) for medium estrogen dose contraceptives.

Conclusion

Strenuous physical activity did not increase the risk for VTE among a large cohort of young adult female individuals.

Postoperative venous thromboembolism risk-prediction in foot and ankle fracture surgery

BACKGROUND

Venous thromboembolism (VTE) are rare but serious complications after foot and ankle fracture surgery. A consensus definition of a high-risk patient has not been reached, leading to significant variability in the use of pharmacologic agents for VTE prophylaxis. The aim of this study was to develop a model for predicting VTE risk in patients undergoing surgery for foot and ankle fractures that is usable and scalable in clinical practice.

METHODS

A retrospective review of 15,342 patients, within the ACS-NSQIP database, who had undergone surgical repair of foot and ankle fractures from 2015 to 2019 was performed. Univariate analysis evaluated differences in demographics and comorbidities. Stepwise multivariate logistic regression was generated based on a 60 % development cohort to evaluate risk factors for VTE. A receiver operator curve based on the 40 % test cohort calculated area under the curve (AUC) to measure the accuracy of the model in predicting VTE within the 30-day postoperative period.

RESULTS

Of the 15,342 patients, 1.2 % patients experienced VTE, and 98.8 % patients did not. Patients who experienced VTE were significantly older and had an overall higher comorbidity burden. Those who had VTE spent on average 10.5 more minutes in the operating room. In the final model, age over 65, diabetes, dyspnea, CHF, dialysis, wound infection and bleeding disorders were all found to be significant predictors of VTE after controlling for all other factors. The model generated an AUC of 0.731, indicating good predictive accuracy. The predictive model is publicly available at https://shinyapps.io/VTE_Prediction/.

CONCLUSIONS

In alignment with previous studies, we identified increased age and bleeding disorders as independent risk factors for VTE after foot and ankle fracture surgery. This is one of the first studies to generate and test a model for identifying patients at risk for VTE in this population. This evidence-based model may help surgeons prospectively identify high-risk patients who may benefit from pharmacologic VTE prophylaxis.

Multiallelic Copy Number Variation in ORM1 is Associated with Plasma Cell-Free DNA Levels as an Intermediate Phenotype for Venous Thromboembolism

Venous thromboembolism (VTE) is a common disease with high heritability. However, only a small portion of the genetic variance of VTE can be explained by known genetic risk factors. Neutrophil extracellular traps (NETs) have been associated with prothrombotic activity. Therefore, the genetic basis of NETs could reveal novel risk factors for VTE. A recent genome-wide association study of plasma cell-free DNA (cfDNA) levels in the Genetic Analysis of Idiopathic Thrombophilia 2 (GAIT-2) Project showed a significant associated locus near ORM1. We aimed to further explore this candidate region by next-generation sequencing, copy number variation (CNV) quantification, and expression analysis using an extreme phenotype sampling design involving 80 individuals from the GAIT-2 Project. The RETROVE study with 400 VTE cases and 400 controls was used to replicate the results. A total of 105 genetic variants and a multiallelic CNV (mCNV) spanning ORM1 were identified in GAIT-2. Of these, 17 independent common variants, a region of 22 rare variants, and the mCNV were significantly associated with cfDNA levels. In addition, eight of these common variants and the mCNV influenced ORM1 expression. The association of the mCNV and cfDNA levels was replicated in RETROVE (p-value = 1.19 × 10-6). Additional associations between the mCNV and thrombin generation parameters were identified. Our results reveal that increased mCNV dosages in ORM1 decreased gene expression and upregulated cfDNA levels. Therefore, the mCNV in ORM1 appears to be a novel marker for cfDNA levels, which could contribute to VTE risk.

Gout and risk of venous thromboembolism: A systematic review and meta-analysis of cohort studies

BACKGROUND

The association between gout and venous thromboembolism (VTE) remains ambiguous, and the results of current studies are inconsistent. A systematic review and meta-analysis of cohort studies were conducted to comprehensively assess the associations between gout and VTE and its subtypes, deep venous thrombosis (DVT) and pulmonary embolism (PE).

METHODS

PubMed, Web of Science, Embase, Scopus, and the Cochrane Library databases were searched up to June 2021, to identify eligible cohort studies, reporting the association of gout with VTE and its subtypes. We pooled hazard ratios (HRs) with 95% confidence intervals (CIs). Subgroup analysis, sensitivity analysis, and publication bias tests were also conducted.

RESULTS

Five studies involving 642 632 individuals were included. Patients with gout had a statistically significantly higher risk of VTE (HR: 1.33; 95% CI: 1.21, 1.46; P < .001) compared with non-gout controls, and significant associations were also found between gout and DVT (HR: 1.40; 95% CI: 1.22, 1.62; P < .001) and PE (HR: 1.18; 95% CI: 1.07, 1.30; P = .001). Subgroup analysis showed this association in men (HR: 1.37; 95% CI: 1.14, 1.65; P = .001) and women (HR: 1.36; 95% CI: 1.21, 1.53; P < .001) were consistent (P = .980). Meta-regression analysis revealed publication year (P = .005) and quality of study (P = .006) contributed to heterogeneity.

CONCLUSIONS

In conclusion, our study provided evidence that gout was associated with the risk of VTE and its subtypes DVT and PE. However, more prospective and high-quality clinical evidence is required to confirm our findings.

Impact of prothrombin and factor V Leiden mutations on the progression of fibrosis in patients with chronic hepatitis C

Background

The role of thrombotic factors in the pathogenesis and progression of liver fibrosis remains obscure. We aimed to study the relationship between prothrombin G20210A (PT20210) and factor V Leiden (FVL) mutations and the progression of fibrosis and liver function in chronic HCV patients.

Methods

The study included 100 subjects, 88 patients with HCV-related cirrhosis (compensated: 38, decompensated: 50), and 12 controls. Patients with other viral hepatitis or coinfection, inherited metabolic disease, autoimmune hepatitis, hepatic or extrahepatic malignancy, in addition to patients with causes of hypoalbuminemia, elevated bilirubin or prolonged INR not related to cirrhosis were excluded from the study. Relevant clinical data were collected and basic laboratory tests were performed. Liver fibrosis was assessed using APRI and FIB-4 scores. FVL and PT20210 mutations were analyzed.

Results

FVL and PT20210 mutations were significantly higher in decompensated vs. compensated patients (32% vs. 5.3%, P = 0.001; 20% vs. 5.3%, 0.043, respectively) and absent in controls. Both mutations significantly correlated to the duration of infection, platelet count and fibrosis scores. PT20210 mutation significantly correlated to serum albumin and INR. Both mutations significantly predicted fibrosis scores, especially PT20210 (AUROC: 0.833 for APRI and 0.895 for FIB-4).

Conclusions

Both mutations are significantly correlated to fibrosis progression and liver profile and could be considered as markers predicting the need for early and different intervention.

Impact of hereditary thrombophilia on cancer-associated thrombosis, tumour susceptibility and progression: A review of existing evidence

Venous thromboembolism (VTE) is a cardiovascular disorder frequently diagnosed among cancer patients. Aside from being common, VTE severely deteriorates the prognosis of these patients as they face a higher risk of morbidity and mortality, which makes clinical tools able to identify the patients more prompt to thrombogenesis very attractive. Over the years, several genetic polymorphisms have been linked with VTE susceptibility in the general population. However, their clinical usefulness as predictive biomarkers for cancer-related VTE is yet unclear. Furthermore, as a two-way association between cancer and VTE is well-recognized, with haemostatic components fuelling tumour progression, haemostatic gene polymorphisms constitute potential cancer predictive and/or prognostic biomarkers as well. Thus, in this article, we review the existing evidence on the role of these polymorphisms on cancer-related VTE and their impact on cancer onset and progression. Despite the promising findings, the existing studies had inconsistent results most likely due to their limited statistical power and population heterogeneity. Future studies are therefore required to clarify the role of these polymorphisms in setting of malignancy.

High Levels of Complement Activating Enzyme MASP-2 Are Associated With the Risk of Future Incident Venous Thromboembolism

BACKGROUND

Experimental studies have shown that the complement activating enzyme MASP-2 (mannose-binding lectin associated serine protease 2) exhibits a thrombin-like activity and that inhibition of MASP-2 protects against thrombosis. In this study, we investigated whether plasma MASP-2 levels were associated with risk of future venous thromboembolism (VTE) and whether genetic variants linked to MASP-2 levels were associated with VTE risk.

METHODS

We conducted a population-based nested case-control study involving 410 VTE patients and 842 age- and sex-matched controls derived from the Norwegian Tromsø Study. Logistic regression was used to estimate odds ratios (ORs) of VTE across MASP-2 quartiles. Whole-exome sequencing and protein quantitative trait loci analyses were performed to assess genetic variants associated with MASP-2 levels. A 2-sample Mendelian randomization study, also including data from the INVENT consortium (International Network of Venous Thrombosis), was performed to assess causality.

RESULTS

Subjects with plasma MASP-2 in the highest quartile had a 48% higher OR of VTE (OR, 1.48 [95% CI, 1.06-2.06]) and 83% higher OR of deep vein thrombosis (OR, 1.83 [95% CI, 1.23-2.73]) compared with those with MASP-2 levels in the lowest quartile. The protein quantitative trait loci analysis revealed that 3 previously described gene variants, rs12711521 (minor allele frequency, 0.153), rs72550870 (minor allele frequency, 0.045; missense variants in the MASP2 gene), and rs2275527 (minor allele frequency, 0.220; exon variant in the adjacent MTOR gene) explained 39% of the variation of MASP-2 plasma concentration. The OR of VTE per 1 SD increase in genetically predicted MASP-2 was 1.03 ([95% CI, 1.01-1.05] P=0.0011).

CONCLUSIONS

Our findings suggest that high plasma MASP-2 levels are causally associated with risk of future VTE.

Blood Cells and Venous Thromboembolism Risk: A Two-Sample Mendelian Randomization Study

Background

Previous studies have shown that various cell indices are associated with a higher risk of venous thromboembolism (VTE), however, whether these findings reflect a causal relationship remains unclear. Therefore, we performed a two-sample Mendelian randomization (MR) analysis to assess the causal association of various blood cells with VTE risk.

Study Design and Methods

Summary statistics of genetic instruments representing cell indices for erythrocytes, leukocytes, and platelets were extracted from genome-wide association studies of European ancestry, by Two-Sample Mendelian Randomization. Inverse variance weighting (IVW) was used as the primary analytical method for MR. Sensitivity analyses were performed to detect horizontal pleiotropy and heterogeneity.

Results

Genetically predicted red blood cell distribution width, mean reticulocyte volume, and mean red blood cell volume were positively associated with VTE, with odds ratio (OR) of 1.002 [CI 1.000-1.003, P = 0.022), 1.003 (CI 1.001-1.004, P = 0.001, respectively)] and 1.001 (CI 1.000-1.002, P = 0.005). Genetically predicted monocyte count was negatively correlated with VTE, with OR = 0.998 (CI 0.996-0.999, P = 0.041).

Conclusion

Genetically liability to high- red blood cell distribution width, mean reticulocyte volume, mean red blood cell volume, and low monocyte count are associated with the higher risk of VTE. Targeting these factors might be a potential strategy to prevent VTE.

Characteristics and Predictors of Venous Thromboembolism Among Lymphoma Patients Undergoing Chemotherapy: A Cohort Study in China

Background: Venous thromboembolism (VTE) is a potential complication among lymphoma patients. We evaluated the incidence rate and predictors of VTE in lymphoma patients undergoing chemotherapy.

Methods: The present study retrospectively studied 1,069 patients with lymphoma who were treated with chemotherapy from 2018 to 2020. We investigated clinical predictors of VTE among all patients. The follow-up results were obtained via telephone communication and from inpatient and outpatient records.

Results: A total of 1,069 patients underwent chemotherapy for lymphoma. During a mean follow-up of 23.1 months, 52 (4.9%) patients developed VTE. According to a multivariate analysis, the five variables found to be independently associated with VTE were male sex (HR 2.273, 95% CI 1.197–4.316, p = 0.012), age >64-years-old (HR 2.256, 95% CI 1.017–5.005, p = 0.045), the number of cycles of chemotherapy (HR 4.579, 95% CI 1.173–17.883, p = 0.029), platelet count ≥350 × 10⁹/L (HR 2.533, 95% CI 1.187–5.406, p = 0.016), and D-dimer >0.5 mg/L (HR 4.367, 95% CI 2.124–8.981, p < 0.001).

Conclusion: This population-based study confirms the risk factors for VTE among patients with lymphoma who underwent chemotherapy and confirms that targeted thromboprophylaxis may reduce the burden of VTE in this population.

Clinical characteristics and risk factors predictive of pulmonary embolism complicated in bronchiectasis patients: a retrospective study

Objective

Pulmonary embolism (PE) is a rare complication in bronchiectasis (BE) patients associated with a high rate of mortality and morbidity. However, data regarding bronchiectasis patients complicated with PE are limited. Early diagnosis of PE in bronchiectasis patients can improve the prognosis, this study aimed to investigate the clinical features and potential risk factors for early diagnosis of PE in bronchiectasis patients.

Methods

Data of Patients were collected from Tongji Hospital of Tongji University of China. Bronchiectasis patients complicated with pulmonary embolism were named as BE/PE group (n = 63), as well as contemporaneous aged- and sex-matched bronchiectasis patients without pulmonary embolism named as BE group (n = 189), at a ratio of 1:3(cases to controls). Clinical parameters and risk factors were analyzed.

Results

Univariate analysis shows that long-term bed rest, chronic lung disease, autoimmune disease, peripheral artery disease (PAD), tuberculosis history, dyspnea, blood homocysteine, CD4/CD8 ratio, or SIQIIITIII syndrome were closely correlated with the incidence of PE in the bronchiectasis patients (p < 0.05). Multivariate logistic regression analysis of significant variables showed that CD4/CD8 ratio (OR 1.409, 95% CI 1.045–1.901) and autoimmune disease (OR 0.264, 95% CI 0.133–0.524) are independent risk factors for BE/PE patients, compared with the BE patients. 53 out of 189 (28.0%) BE patients had hemoptysis, and 15 out of 63 (23.8%) BE/PE patients had hemoptysis (p > 0.05).

Conclusions

The coexistence of pulmonary embolism and bronchiectasis are rarely encountered and easily to be ignored. Early identification of the clinical characteristic and potential risk factors of pulmonary embolism in bronchiectasis patients may help optimize the treatment strategies.

Ruscogenin alleviates deep venous thrombosis and pulmonary embolism induced by inferior vena cava stenosis inhibiting MEK/ERK/Egr-1/TF signaling pathway in mice

BACKGROUND

Ruscogenin (RUS) has anti-inflammatory and antithrombotic effects, while its potential effects on deep venous thrombosis (DVT) and pulmonary embolism (PE) remain unclear.

OBJECTIVE

We aimed to elucidate the effects of RUS on DVT and PE induced by the inferior vena cava stenosis (IVCS) model and investigate the underlying mechanism.

METHODS

Male C57/BL6 mice were used to explore whether IVCS model could be complicated with deep venous thrombosis and pulmonary embolism. Then, Effects of RUS on DVT and PE related inflammatory factors and coagulation were examined using H&E staining, ELISA, and real-time PCR. Western blot analysis was used to examine the effects of RUS on MEK/ERK/Egr-1/TF signaling pathway in PE.

RESULTS

IVCS model induced DVT and complied with PE 48 h after surgery. Administration of RUS (0.01, 0.1, 1 mg/kg) inhibited DVT, decreased biomarker D-Dimer, cardiac troponin I, N-Terminal probrain natriuretic peptide in plasma to ameliorate PE induced by IVCS model. Meanwhile, RUS reduced tissue factor and fibrinogen content of lung tissue, inhibited P-selectin and C-reactive protein activity in plasma, and suppressed the expressions of interleukin-6 and interleukin-1β in mice. Furthermore, RUS suppressed the phosphorylation of ERK1/2 and MEK1/2, decreasing the expressions of Egr-1 and TF in the lung.

CONCLUSION

IVCS model contributed to the development of DVT and PE in mice and was associated with increased inflammation. RUS showed therapeutic effects by inhibiting inflammation as well as suppressing the activation of MEK/ERK/Egr-1/TF signaling pathway.

Search for Venous Endothelial Biomarkers Heralding Venous Thromboembolism in Space: A Qualitative Systematic Review of Terrestrial Studies

Background: The recent discovery of a venous thrombosis in the internal jugular vein of an astronaut has highlighted the need to predict the risk of venous thromboembolism in otherwise healthy individuals (VTE) in space. Virchow’s triad defines the three classic risk factors for VTE: blood stasis, hypercoagulability, and endothelial disruption/dysfunction. Among these risk factors, venous endothelial disruption/dysfunction remains incompletely understood, making it difficult to accurately predict risk, set up relevant prophylactic measures and initiate timely treatment of VTE, especially in an extreme environment.

Methods: A qualitative systematic review focused on endothelial disruption/dysfunction was conducted following the guidelines produced by the Space Biomedicine Systematic Review Group, which are based on Cochrane review guidelines. We aimed to assess the venous endothelial biochemical and imaging markers that may predict increased risk of VTE during spaceflight by surveying the existing knowledge base surrounding these markers in analogous populations to astronauts on the ground.

Results: Limited imaging markers related to endothelial dysfunction that were outside the bounds of routine clinical practice were identified. While multiple potential biomarkers were identified that may provide insight into the etiology of endothelial dysfunction and its link to future VTE, insufficient prospective evidence is available to formally recommend screening potential astronauts or healthy patients with any currently available novel biomarker.

Conclusion: Our review highlights a critical knowledge gap regarding the role biomarkers of venous endothelial disruption have in predicting and identifying VTE. Future population-based prospective studies are required to link potential risk factors and biomarkers for venous endothelial dysfunction to occurrence of VTE.

Variation in Plasma Levels of Apixaban and Rivaroxaban in Clinical Routine Treatment of Venous Thromboembolism

Direct oral anticoagulants (DOACs) apixaban and rivaroxaban are broadly used in the management of venous thromboembolism (VTE). Although not routinely required, measurement of their plasma concentration is advised for an increasing number of indications. Due to the lack of therapeutic ranges, current guidelines recommend reporting DOAC plasma levels together with expected levels from previous pivotal studies. The aim of this study was to assess DOAC level variation in a large VTE patient population. Drug concentrations determined by measurement of the anti-Xa-activity using drug-specific calibrators in citrated plasma samples from patients on rivaroxaban (n = 1471) or apixaban (n = 725) were analyzed. Observed 5th–95th percentile ranges of apixaban peak/trough levels (63–299/13–114 ng/mL for 5 mg, 37–161/7–68 ng/mL for 2.5 mg twice daily) were similar to previously reported mass-spectrometry-based reference data, and 10th–90th percentile ranges of rivaroxaban peak/trough levels (98–367/8–55 ng/mL for 20 mg, 51–211/5–27 ng/mL for 10 mg once daily) were even narrower. Age and drug levels correlated weakly (r ≤ 0.330). Drug levels measured repeatedly in subgroups of patients showed a strong correlation (r ≥ 0.773). In conclusion, anti-Xa-activity-based measurement of apixaban and rivaroxaban yields reliable results. However, the paucity of levels off-range underlines the need for evidence-based thresholds to better assist clinical decision making.

Comparison of DNA Methylation Changes Between the Gestation Period and the After-Delivery State: A Pilot Study of 10 Women

Background

Gestational adaptation occurs soon after fertilization and continues throughout pregnancy, whereas women return to a pre-pregnancy state after delivery and lactation. However, little is known about the role of DNA methylation in fine-tuning maternal physiology. Understanding the changes in DNA methylation during pregnancy is the first step in clarifying the association of diet, nutrition, and thromboembolism with the changes in DNA methylation. In this study, we investigated whether and how the DNA methylation pattern changes in the three trimesters and after delivery in ten uncomplicated pregnancies.

Results

DNA methylation was measured using a Human MethylationEPIC BeadChip. There were 14,018 cytosine-guanine dinucleotide (CpG) sites with statistically significant changes in DNA methylation over the four time periods (p < 0.001). Overall, DNA methylation after delivery was higher than that of the three trimesters (p < 0.001), with the protein ubiquitination pathway being the top canonical pathway involved. We classified the CpG sites into nine groups according to the changes in the three trimesters and found that 38.37% of CpG sites had DNA methylation changes during pregnancy, especially between the first and second trimesters.

Conclusion

DNA methylation pattern changes between trimesters, indicating possible involvement in maternal adaptation to pregnancy. Meanwhile, DNA methylation patterns during pregnancy and in the postpartum period were different, implying that puerperium repair may also function through DNA methylation mechanisms.

Overactivation of IL6 cis‑signaling in leukocytes is an inflammatory hallmark of deep vein thrombosis

Inflammation is a protective response of the body to various injuries, which is strictly regulated by a variety of factors, including immune cells and soluble mediators. However, dysfunction of this defensive mechanism often results in inflammation‑driven diseases, such as deep vein thrombosis (DVT). The complex relationship between inflammatory cell activity and DVT has not been fully elucidated. The present study aimed to investigate the role of interleukin‑6 (IL6) signaling transduction in DVT. To this aim, the expression levels of transmembrane isoforms of the IL6 receptor (IL6R) and the glycoprotein 130 responsible for the IL6 cis‑signaling were evaluated in the peripheral blood mononuclear cells of patients with DVT and of healthy controls. The results indicated that leukocytes from patients with DVT exhibited overexpression of both IL6R and gp130 membrane isoforms and that these were strongly associated with the occurrence of DVT. Overall, the present findings indicated that IL6 cis‑signaling may have a direct involvement in the leukocyte activation in DVT and may serve as a predictive biomarker of DVT development.

The Emerging Role of Neutrophil Extracellular Traps in Arterial, Venous and Cancer-Associated Thrombosis

Neutrophils play a vital role in the formation of arterial, venous and cancer-related thrombosis. Recent studies have shown that in a process known as NETosis, neutrophils release proteins and enzymes complexed to DNA fibers, collectively called neutrophil extracellular traps (NETs). Although NETs were originally described as a way for the host to capture and kill bacteria, current knowledge indicates that NETs also play an important role in thrombosis. According to recent studies, the destruction of vascular microenvironmental homeostasis and excessive NET formation lead to pathological thrombosis. In vitro experiments have found that NETs provide skeletal support for platelets, red blood cells and procoagulant molecules to promote thrombosis. The protein components contained in NETs activate the endogenous coagulation pathway to promote thrombosis. Therefore, NETs play an important role in the formation of arterial thrombosis, venous thrombosis and cancer-related thrombosis. This review will systematically summarize and explain the study of NETs in thrombosis in animal models and in vivo experiments to provide new targets for thrombosis prevention and treatment.

Role of ADAMTS13, VWF and F8 genes in deep vein thrombosis

Background

We previously described the association between rare ADAMTS13 single nucleotide variants (SNVs) and deep vein thrombosis (DVT). Moreover, DVT patients with at least one rare ADAMTS13 SNV had a lower ADAMTS13 activity than non-carriers.

Aims

To confirm ADAMTS13 variants association with DVT and reduced plasma ADAMTS13 activity levels in a larger population. To investigate the role of VWF and F8 variants.

Methods

ADAMTS13, VWF and F8 were sequenced using next-generation sequencing in 594 Italian DVT patients and 571 controls. Genetic association testing was performed using logistic regression and gene-based tests. The association between rare ADAMTS13 variants and the respective plasmatic activity, available for 365 cases and 292 controls, was determined using linear regression. All analyses were age-, sex- adjusted.

Results

We identified 48 low-frequency/common and 272 rare variants. Nine low-frequency/common variants had a P<0.05, but a false discovery rate between 0.06 and 0.24. Of them, 7 were found in ADAMTS13 (rs28641026, rs28503257, rs685523, rs3124768, rs3118667, rs739469, rs3124767; all protective) and 2 in VWF (rs1800382 [risk], rs7962217 [protective]). Rare ADAMTS13 variants were significantly associated with DVT using the burden, variable threshold (VT) and UNIQ (P<0.05), but not with C-ALPHA, SKAT and SKAT-O tests. Rare VWF and F8 variants were not associated with DVT. Carriers of rare ADAMTS13 variants had lower ADAMTS13 activity than non-carriers (ß -6.2, 95%CI -11,-1.5). This association was stronger for DVT patients than controls (ß -7.5, 95%CI -13.5,-1.5 vs. ß -2.9, 95%CI -10.4,4.5).

Conclusions

ADAMTS13 and VWF low-frequency/common variants mainly showed a protective effect, although their association with DVT was not confirmed. DVT patients carrying a rare ADAMTS13 variants had slightly reduced ADAMTS13 activity levels, but a higher DVT risk. Rare VWF and FVIII variants were not associated with DVT suggesting that other mechanisms are responsible for the high VWF and FVIII levels measured in DVT patients.

Stabilin-2 deficiency increases thrombotic burden and alters the composition of venous thrombi in a mouse model

BACKGROUND

Stabilin-2 is an endocytic scavenger receptor that mediates the clearance of glycosaminoglycans, phosphatidylserine-expressing cells, and the von Willebrand factor-factor VIII (FVIII) complex. In a genome-wide screening study, pathogenic loss-of-function variants in the human STAB2 gene associated with an increased incidence of unprovoked venous thromboembolism (VTE). However, the specific mechanism(s) by which stabilin-2 deficiency influences the pathogenesis of VTE is unknown.

OBJECTIVES

The aim of this study was to assess the influence of stabilin-2 on deep vein thrombosis (DVT) and to characterize the underlying prothrombotic phenotype of stabilin-2 deficiency in a mouse model.

METHODS

DVT was induced using the inferior vena cava (IVC) stenosis model in two independent cohorts (littermates and non-littermates) of wild-type (Stab2+/+ ) and stabilin-2 (Stab2-/- )-deficient mice. Thrombus structure and contents were quantified by immunohistochemistry. Plasma procoagulant activity was assessed and complete blood counts were performed.

RESULTS

Incidence of thrombus formation was not altered between Stab2+/+ and Stab2-/- mice. When thrombi were formed, Stab2-/- mice developed significantly larger thrombi than Stab2+/+ controls. Thrombi from Stab2-/- mice contained significantly more leukocytes and citrullinated histone H3 than Stab2+/+ thrombi. Stab2-/- mice had increased FVIII activity. Circulating levels of monocytes and granulocytes were significantly elevated in Stab2-/- mice, and Stab2-/- mice had elevated plasma cell-free DNA 24 hours post-IVC stenosis compared to their Stab2+/+ counterparts.

CONCLUSIONS

These data suggest that stabilin-2 deficiency associates with a prothrombotic phenotype involving elevated levels of neutrophil extracellular trap-releasing leukocytes coupled with endogenous procoagulant activity, resulting in larger and qualitatively distinct venous thrombi.

The secret enemy during a flight: Economy class syndrome

Deep venous thrombosis (DVT) and pulmonary thromboembolism (PTE) are the major causes of morbidity and mortality in immobile patients. There is observational evidence that intercontinental air travel is associated with a high incidence of DVT and PTE during or within 48 hours of long-distance flights. This situation is known as the economy class syndrome and can affect both the cabin crew and passengers. The term "economy class syndrome" refers to the occurrence of thrombotic events that mainly occur in passengers in the economy class of the aircraft during long-haul flights. This syndrome results from several factors related to the aircraft cabin and the passenger, acting together to predispose to excessive blood coagulation, which can result in venous thromboembolism. In this review, we have shared the relationship between air travel and the formation of DVT and PTE.

Venous thromboembolic events in T-cell lymphoma patients: Incidence, risk factors and clinical features

INTRODUCTION

Patients with hematologic malignancies are prone to developing thromboembolism. The incidence, risk factors and clinical features for developing venous thromboembolism (VTE) are not well-elucidated in patients with T-cell lymphoma.

MATERIALS AND METHODS

The present study retrospectively analyzed 668 patients with VTE, including pulmonary embolism (PE) and deep vein thrombosis (DVT), who were admitted to Tianjin Medical University Cancer Institute and Hospital and Sun Yat-sen University Cancer Center from January 2006 to December 2018. All patients were diagnosed with T-cell lymphoma, and all episodes of symptomatic VTE were confirmed by imaging and ultrasound. The follow-up results were obtained through telephone communication and outpatient visits.

RESULTS

A total of 668 patients were analyzed. Thirty-three (4.94%) patients had at least one episode of VTE, and all of which were deep vein thrombosis alone. All VTEs occurred in patients who received chemotherapy, while no VTE occurred in patients who did not receive chemotherapy. By univariate analysis, central venous catheter (CVC) (odds ratio [OR] 6.63, confidence interval [CI] 2.24-19.57, P = 0.001), Eastern Cooperative Oncology Group (ECOG) performance status 2, 3, or 4 (OR: 62.15, CI: 15.42-250.48, P = 0.000), and stage III or IV (OR: 4.06, CI: 1.00-16.40, P = 0.049) were identified as risk factors for developing VTE. By multivariate analysis, CVC (OR: 3.23, CI: 1.49-7.23, P = 0.003) and stage III or IV (OR: 2.30, CI: 1.06-4.97, P = 0.035) were still significant risk factors for developing VTE.

CONCLUSION

The incidence of VTE in the present study population was comparable to that of lymphoma patients, other than T-cell lymphoma, and VTE was associated with CVC and advanced stage.

Overall and abdominal obesity in relation to venous thromboembolism

BACKGROUND

Abdominal obesity has been shown to be a superior measure over overall obesity for detecting cardiovascular risk.

OBJECTIVE

We conducted this study to compare the effects of overall and abdominal obesity on venous thromboembolism (VTE) and to calculate population attributable fraction for obesity for VTE.

METHODS

Body mass index (BMI) and waist circumference (WC) were used to represent overall and abdominal obesity, respectively. In the cohort study, we included 74317 Swedish adults with anthropometric measures in 1997 and of whom 4332 were diagnosed with VTE until the end of 2017. A Mendelian randomization study was conducted to investigate causal associations of BMI, WC, and WC adjusted for BMI with VTE using data from FinnGen and UK Biobank study. Population attributable fraction was calculated for overall and abdominal obesity for VTE.

RESULTS

In the cohort study, there were dose-response associations of BMI and WC with VTE. The association between BMI and VTE was attenuated largely after adjusting for WC. Among individuals with normal BMI, participants with substantially increased WC had 53% higher (hazard ratio 1.53; 95% confidence interval, 1.28, 1.81) risk of VTE compared to those with normal WC. The causality of the association of WC adjusted for BMI with VTE was confirmed in Mendelian randomization analysis. The estimated population-attributable risk due to elevated BMI and WC were 12.4% (8.4%, 16.5%) and 23.7% (18.1%, 29.4%), respectively.

CONCLUSIONS

WC might be a preferable indicator linking obesity to VTE. A large proportion of VTE cases can be prevented if the population maintained a healthy BMI and WC.

The Association between Blood-Based Global DNA Methylation and Venous Thromboembolism

Alterations in DNA methylation patterns have been associated with many diseases. However, the role of DNA methylation in venous thromboembolism (VTE) is not well established. The aim of this study was to investigate a possible association between global DNA methylation and VTE. The study participants consisted of 168 individuals including 74 patients with primary VTE from the Malmö Thrombophilia Study (MATS) and 94 healthy controls. Among 74 primary VTE patients, 37 suffered VTE recurrence during the follow-up period; 37 nonrecurrent VTE patients were included for comparison. Blood-based global DNA methylation was assessed by an enzyme-linked immunosorbent assay. Global DNA methylation was significantly higher in primary VTE patients compared with the healthy controls (median: 0.17 vs. 0.08%; p < 0.001). After stratification of data from primary VTE patients according to sex, the association between higher global DNA methylation and shorter recurrence-free survival time was of borderline statistical significance in males (β = -0.2; p = 0.052) but not in females (β = 0.02; p = 0.90). Our results show that global DNA methylation is associated with primary VTE and that higher levels of global DNA methylation may be associated with early VTE recurrence in males but not in females. Further investigation on the role of DNA methylation as a diagnostic or preventive biomarker in VTE is warranted.

Implications of venous thromboembolism GWAS reported genetic makeup in the clinical outcome of ovarian cancer patients

Ovarian cancer (OC) represents the most lethal gynaecological neoplasia. Conversely, venous thromboembolism (VTE) and OC are intricately connected, with many haemostatic components favouring OC progression. In light of this bilateral relationship, genome-wide association studies (GWAS) have reported several single-nucleotide polymorphisms (SNPs) associated with VTE risk that could be used as predictors of OC clinical outcome for better therapeutic management strategies. Thus, the present study aimed to analyse the impact of VTE GWAS-identified SNPs on the clinical outcome of 336 epithelial ovarian cancer (EOC) patients. Polymorphism genotyping was performed using the TaqMan^® Allelic Discrimination methodology. Carriers with the ZFPM2 rs4734879 G allele presented a significantly higher 5-year OS, 10-year OS and disease-free survival (DFS) compared to AA genotype patients with FIGO I/II stages (P = 0.009, P = 0.001 and P = 0.003, respectively). Regarding SLC19A2 rs2038024 polymorphism, carriers with the CC genotype presented a significantly lower 5-year OS, 10-year OS and DFS compared to A allele carriers in the same FIGO subgroup (P < 0.001, P = 0.004 and P = 0.005, respectively). As for CNTN6 rs6764623 polymorphism, carriers with the CC genotype presented a significantly lower 5-year OS compared to A allele carriers with FIGO I/II stages (P = 0.015). As for OTUD7A rs7164569, F11 rs4253417 and PROCR rs10747514, no significant impact on EOC patients' survival was observed. However, future studies are required to validate these results and uncover the biological mechanisms underlying our results.

COVID-19 in clinical practice: A narrative synthesis

The coronavirus disease 2019 (COVID-19) was first reported in the city of Wuhan, China. The disease rapidly spread to the rest of China, to Southern-East Asia, then to Europe, America, and on to the rest of the world. COVID-19 is associated with a betacoronavirus named SARS-CoV-2. The virus penetrates the organism through the respiratory tract, conveyed by contaminated droplets. The main cell receptor targeted is the surface-bound ACE-2. As of the 26th July 2020, 15,200,000 COVID-19 cases and 650,000 deaths were reported worldwide. The mortality rate is estimated between 1.3 and 18.3%. The reproductive rate without any public health intervention is estimated around 4-5.1 in France. Most hospitalized patients for COVID-19 present respiratory symptoms, which in some cases is associated with fever. Up to 86% of admissions to ICU are related to acute respiratory failure. To date, no anti-viral therapy has proven its efficacy considering randomized trials. Only immunomodulatory treatments such as corticosteroids have shown to cause significant improvement in patient outcome.

Direct oral anticoagulant treatment of deep vein thrombosis reduces IL-6 expression in peripheral mono-nuclear blood cells

Multiple factors play a pathophysiologic role for the venous thromboembolism (VTE) as a multi-factorial disease. Inflammation might play a peculiar role in shifting towards a pro-thrombotic state. Anticoagulant drugs are the first cure line for VTE. The low-molecular-weight heparins (LMWH) show anti-coagulant capability as well as reducing levels of inflammatory factors, including interleukin (IL)-6. The direct oral anticoagulants (DOACs) have shown efficacy in threating VTE, additionally to the anti-activated factor X these drugs seem able to reduce the abnormal release of pro-inflammatory agents. The present study evaluated the capability of DOACs in reducing plasma level of IL-6 in patients suffered from deep vein thrombosis (DVT) of the lower limbs. Our results showed reduced IL-6 expression levels in the peripheral lymphocytes of DVT compared to controls (fold-change, 2.8; P<0.05). We postulate that lowered IL-6 expression in the lymphocytes of DVT patients may mediate the anti-inflammatory action of DOACs. The present study is the first evidence concerning the anti-inflammatory properties of DOACs in specific setting of VTE patients such as DVT.

Recent advances in understanding, diagnosing and treating venous thrombosis

Focusing on the current state of the art, this article (a) describes recent advances in the understanding of the pathogenesis of venous thromboembolism (VTE), (b) discusses current approaches for the prevention, diagnosis and treatment of VTE, (c) outlines the role of aspirin for VTE prevention and treatment, and (d) highlights the unmet needs in VTE management and describes novel approaches to address them.

In Well-Selected Patients With a Femoral Deep Vein Thrombosis Central Venous Imaging May Identify Additional Iliocaval Disease

OBJECTIVE

Patients who present acutely with a femoral deep vein thrombosis (DVT) diagnosed by ultrasound are often treated with anticoagulation and instructed to follow-up electively. This study sought to assess whether obtaining axial imaging of the central venous system results in the identification of additional iliocaval pathology warranting treatment.

METHODS

This study was a retrospective review of a prospectively maintained registry from November 2014 through April 2017 with follow-up through March 2020. Consecutive patients with a diagnosis of femoral DVT diagnosed by ultrasound were evaluated; those who underwent axial imaging of the iliocaval system (Group A) were compared to those who did not undergo imaging of the central veins (Group B). The primary outcome was the performance of any percutaneous central venous intervention. Secondary outcomes included the extent of DVT identified on duplex and after axial imaging, follow-up duplex patency and persistence of severe symptoms.

RESULTS

Eighty patients presented with an ultrasound diagnosis of a femoral vein DVT. Mean follow-up was 551 ± 502 days. Group A comprised 24 patients (30%) and Group B comprised 56 patients (70%). Baseline demographics did not differ significantly between the 2 groups. After duplex imaging, Group A exhibited an increased prevalence of DVT in the common femoral vein. After central imaging, Group A exhibited an increased prevalence of DVT in the iliocaval veins. The number of patients who underwent invasive treatment differed significantly between the 2 groups, Group A 16/24 (67%) vs. Group B 9/56 (16%), P < 0.0001. The number of patients that demonstrated duplex patency and had persistent symptoms on follow-up did not differ significantly.

CONCLUSIONS

Patients with an ultrasound diagnosis of femoral DVT may have additional iliocaval pathology warranting intervention. Well-selected imaging of the central veins may reveal a more complete picture, potentially altering management.

Profile of Patients Diagnosed With Acute Venous Thromboembolism in Routine Clinical Practice: The RE-COVERY DVT/PE™ Study

BACKGROUND

The safety and efficacy of nonvitamin K antagonist oral anticoagulants (NOACs) for the treatment of venous thromboembolism (VTE) have been established in randomized controlled trials, but limited data are available on their use in clinical practice across geographical regions.

METHODS

In the international RE-COVERY DVT/PE observational study (enrollment January 2016 to May 2017), we sought to characterize the patient population and describe the prescribed anticoagulant. Patient characteristics and anticoagulants administered after objective diagnosis of VTE were recorded at the baseline visit and again at hospital discharge or at 14 days after the diagnosis, whichever was later.

RESULTS

A total of 6095 patients were included, 50.2% were male, and the mean age was 61.5 years. The most common comorbidities were hypertension (35%), diabetes mellitus (11%), cancer (11%), prior VTE(11%), and trauma/surgery (7%). Overall, 77% of patients received oral anticoagulants, with 54% on NOACs and 23% on vitamin K antagonists (VKAs); 20% received parenteral anticoagulation only. NOACs comprised about 60% of anticoagulant treatment in Europe and Asia but substantially less in Latin America (29%) and the Middle East (21%). For NOAC therapies, the distribution (as a percentage of the total cohort) was rivaroxaban 25.6%, dabigatran 15.5%, apixaban 11.3%, and edoxaban 1.7%. Treatment with NOACs was less frequent in patients who had cancer, chronic renal disease, heart failure, or stroke.

CONCLUSIONS

These findings enhance our understanding of baseline characteristics and the initial management of patients with VTE in routine practice.

Thrombogenic and Inflammatory Reactions to Biomaterials in Medical Devices

Blood-contacting medical devices of different biomaterials are often used to treat various cardiovascular diseases. Thrombus formation is a common cause of failure of cardiovascular devices. Currently, there are no clinically available biomaterials that can totally inhibit thrombosis under the more challenging environments (e.g., low flow in the venous system). Although some biomaterials reduce protein adsorption or cell adhesion, the issue of biomaterial associated with thrombosis and inflammation still exists. To better understand how to develop more thrombosis-resistant medical devices, it is essential to understand the biology and mechano-transduction of thrombus nucleation and progression. In this review, we will compare the mechanisms of thrombus development and progression in the arterial and venous systems. We will address various aspects of thrombosis, starting with biology of thrombosis, mathematical modeling to integrate the mechanism of thrombosis, and thrombus formation on medical devices. Prevention of these problems requires a multifaceted approach that involves more effective and safer thrombolytic agents but more importantly the development of novel thrombosis-resistant biomaterials mimicking the biological characteristics of the endothelium and extracellular matrix tissues that also ameliorate the development and the progression of chronic inflammation as part of the processes associated with the detrimental generation of late thrombosis and neo-atherosclerosis. Until such developments occur, engineers and clinicians must work together to develop devices that require minimal anticoagulants and thrombolytics to mitigate thrombosis and inflammation without causing serious bleeding side effects.

Benefits may not outweigh risks of low molecular weight heparin (LMWH) in early postoperative thromboprophylaxis following minimally invasive cardiac surgery: a propensity score-matched analysis

Background

Whether the benefits of early prophylactic anticoagulation by low molecular weight heparin (LMWH) would outweigh its possible harms in patients after minimally invasive cardiac surgery (MICS) remains contentious. The aims of this study were to define the incidence of venous thromboembolism (VTE) and to assess whether early prophylactic anticoagulation by LMWH postoperatively was indeed effective in reducing VTE without increasing risk of complications after MICS.

Methods

This investigation was a single-center, retrospective, propensity score-matched analysis study. A total of 473 patients underwent MICS, of whom 257 received prophylactic anticoagulation with LMWH (LMWH group) in the early postoperative period and 216 were not treated with LMWH (Control group). The main outcome measurements included the incidence of embolism events and major bleeding events, the volume of erythrocyte transfusion, the volume of drainage and the duration of drainage after MICS. In addition, the incidence of poor wound healing, the mechanical ventilation time, ICU stay time and postoperative hospitalization time were also documented.

Results

There were fewer embolic events (P=1.000) and a higher rate of major bleeding events (P=0.008) in the LMWH group than the Control group, and their magnitude and significance were maintained in the propensity matched analysis. In the matched cohorts, there was no significant difference in the total volume of red blood cell transfusion (P=0.552), assisted mechanical ventilation time (P=0.542), and the ICU stay time (P=0.166) between the two groups; while the volume of drainage (P<0.001) and the duration of drainage (P<0.001) in the LMWH group were significantly more than the Control group, and the incidence of poor wound healing (P=0.009) and the postoperative hospitalization time (P<0.001) were significantly increased in the LMWH group.

Conclusions

Early prophylactic anticoagulation with LMWH could not reduce the incidence of embolism events after MICS. Instead, it might increase postoperative major bleeding events and prolong drainage tube indwelling time and the length of hospital stay.

The use of intermittent pneumatic compression to prevent venous thromboembolism in neurosurgical patients-A systematic review and meta-analysis

OBJECTIVE

The incidence of venous thromboembolism (VTE) remains high despite the use of low-molecular weight heparin (LMWH) and compression stocking (CS). We aimed to evaluate the use of IPC as VTE prophylaxis in neurosurgical patients.

PATIENTS AND METHODS

We conducted meta-analysis to assess the use of IPC as VTE prophylaxis in neurosurgical patients from several databases.

RESULTS

There was a total of 7.515 subjects from 5 studies. Reduction in VTE incidence was demonstrated by the IPC group (OR 0.40 [0.31, 0.52], p < 0.001; I²: 44 %). IPC was shown to reduce the incidence of deep venous thrombosis (DVT) (OR 0.43 [0.32, 0.57], p < 0.001; I²: 0 %) compared to the control group. Incidence of pulmonary embolism (PE) was lower (OR 0.42 [0.25, 0.70], p < 0.001; I²: 80 %) in IPC. Upon sensitivity analysis, PE was significantly lower in IPC (OR 0.24 [0.13, 0.45], p < 0.001; I²: 0 %). Subgroup analysis on patients undergoing neurosurgical intervention (operation) and receiving LMWH + CS shows a markedly reduced incidence of VTE (OR 0.37 [0.28, 0.50], p < 0.001; I²: 3 %), DVT (OR 0.39 [0.28, 0.54], p < 0.001; I²: 0 %), and PE (OR 0.22 [0.11, 0.43], p < 0.001; I²: 0 %) in IPC.

CONCLUSION

Intermittent pneumatic compression was associated with less VTE in neurosurgical patients, especially in those who received neurosurgical interventions, however, the certainty of evidence remained inadequate for creating a strong recommendation and further randomized controlled trials are needed before drawing a definite conclusion.

By word of mouse: using animal models in venous thrombosis research

Deep vein thrombosis (DVT) is a disease with high prevalence and morbidity. It can lead to pulmonary embolism with severe respiratory insufficiency and risk of death. Mechanisms behind all stages of DVT, such as thrombosis commencement, propagation, and resolution, remain incompletely understood. Animal models represent an invaluable tool to explore these problems and identify new targets for DVT prevention and treatment. In this review, we discuss existing models of venous thrombosis, their advantages and disadvantages, and applicability to studying different aspects of DVT pathophysiology. We also speculate about requirements for an "ideal model" that would best recapitulate features of human DVT and discuss readouts of various models.

Identification of Common and Rare Genetic Variation Associated With Plasma Protein Levels Using Whole-Exome Sequencing and Mass Spectrometry

BACKGROUND

Identifying genetic variation associated with plasma protein levels, and the mechanisms by which they act, could provide insight into alterable processes involved in regulation of protein levels. Although protein levels can be affected by genetic variants, their estimation can also be biased by missense variants in coding exons causing technical artifacts. Integrating genome sequence genotype data with mass spectrometry-based protein level estimation could reduce bias, thereby improving detection of variation that affects RNA or protein metabolism.

METHODS

Here, we integrate the blood plasma protein levels of 664 proteins from 165 participants of the Tromsø Study, measured via tandem mass tag mass spectrometry, with whole-exome sequencing data to identify common and rare genetic variation associated with peptide and protein levels (protein quantitative trait loci [pQTLs]). We additionally use literature and database searches to prioritize putative functional variants for each pQTL.

RESULTS

We identify 109 independent associations (36 protein and 73 peptide) and use genotype data to exclude 49 (4 protein and 45 peptide) as technical artifacts. We describe 2 particular cases of rare variation: 1 associated with the complement pathway and 1 with platelet degranulation. We identify putative functional variants and show that pQTLs act through diverse molecular mechanisms that affect both RNA and protein metabolism.

CONCLUSIONS

We show that although the majority of pQTLs exert their effects by modulating RNA metabolism, many affect protein levels directly. Our work demonstrates the extent by which pQTL studies are affected by technical artifacts and highlights how prioritizing the functional variant in pQTL studies can lead to insights into the molecular steps by which a protein may be regulated.

Coagulation System Disorders and Thrombosis Prophylaxis During Laparoscopic Fundoplications

BACKGROUND

The aim of this study was to assess and recommend the optimal deep vein thrombosis (DVT) prophylaxis regimen during and after laparoscopic fundoplication according to the blood coagulation disorders and the rate of DVT in 2 patient groups, receiving different DVT prophylaxis regimens.

MATERIALS AND METHODS

This was a prospective randomized, single-center clinical study. The study population, 121 patients, were divided into 2 groups: group I received low-molecular-weight heparin 12 hours before the operation; group II received low-molecular-weight heparin only 1 hour before the laparoscopic fundoplication. Both groups received intermittent pneumatic compression during the entire procedure. Bilateral Doppler ultrasound to exclude DVT was performed before the surgery. Venous phase computed tomographic images were acquired from the ankle to the iliac tubercles on the third postoperative day to determine the presence and location of DVT. Hypercoagulation state was assessed by measuring the prothrombin fragment F1+2 (F1+2), the thrombin-antithrombin complex (TAT), and tissue factor microparticles activity (MP-TF) in plasma. The hypocoagulation effect was evaluated by measuring plasma free tissue factor pathway inhibitor (fTFPI).

RESULTS

F1+2, TAT, and MP-TF indexes increased significantly, whereas fTFPI levels decreased significantly during and after laparoscopic fundoplication, when molecular-weight heparin was administered 12 hours before the operation. Computed tomography venography revealed peroneal vein thrombosis in 2 group I patients on the third postoperative day. Total postsurgical DVT frequency was 1.65%: 3.6% in group I, with no DVT in group II.

CONCLUSION

Molecular-weight heparin and intraoperative intermittent pneumatic compression controls the hypercoagulation effect more efficiently when it is administered 1 hour before surgery: it causes significant reduction of F1+2, TAT, and MP-TF indexes and significant increases of fTFPI levels during and after laparoscopic fundoplication.

Complement activation assessed by the plasma terminal complement complex and future risk of venous thromboembolism

BACKGROUND

It remains uncertain whether activation of the complement system, assessed by the soluble terminal C5b-9 complement complex (plasma TCC), is associated with future risk of incident venous thromboembolism (VTE).

OBJECTIVES

To investigate the association between plasma levels of TCC and future risk of incident VTE in a nested case-control study, and to explore genetic variants associated with TCC using protein quantitative trait loci analysis of exome sequencing data.

METHODS

We sampled 415 VTE cases and 848 age- and sex-matched controls from a population-based cohort, the Tromsø study. Logistic regression models were used to calculate odds ratios with 95% confidence intervals for VTE across quartiles of plasma levels of TCC. Whole exome sequencing was conducted using the Agilent SureSelect 50 Mb capture kit.

RESULTS

The risk of VTE increased across increasing quartiles of plasma TCC, particularly for unprovoked VTE. Participants with TCC in the highest quartile (>1.40 complement arbitrary units/mL) had an odds ratio for unprovoked VTE of 1.74 (95% confidence interval: 1.10-2.78) compared with those with TCC in the lowest quartile (≤0.80 complement arbitrary units/mL) in analyses adjusted for age, sex, and body mass index. A substantially higher risk for VTE was observed in samples taken shortly before VTE event. We found no association between genome-wide or complement-related gene variants and plasma levels of TCC.

CONCLUSIONS

We found that high levels of plasma TCC were associated with VTE risk, and unprovoked events in particular. There was no genome-wide association between gene variants and plasma levels of TCC.

Systemic Lupus Erythematosus Is Associated With a High Risk of Venous Thromboembolism in Hospitalized Patients Leading to Poor Outcomes and a Higher Cost: Results From Nationwide Inpatient Sample Database 2003-2011

Objective

Venous thromboembolism (VTE) is a major cause of mortality and morbidity in hospitalized patients, particularly those with autoimmune disorders. The Nationwide Inpatient Sample (NIS) database was analyzed to determine trends in the rate of hospitalization, mortality from VTE, epidemiology, and outcomes in hospitalized patients with systemic lupus erythematosus (SLE) to assess its impact.

Methods

The 2003‐2011 NIS database of the Healthcare Cost and Utilization Project was queried to identify all adults (age 18 years and older) hospitalized with SLE and VTE. Demographic characteristics and in‐hospital outcomes of this population were compared with those of patients with SLE without a VTE diagnosis. A multivariate logistic regression analysis was used to obtain the adjusted odds ratio (OR).

Results

The total number of hospitalized patients with SLE was 299 595, of whom 9175 (3.06%) had VTE. After adjusting for potential confounders, compared with those without VTE, patients with SLE and VTE had significantly higher inpatient mortality (5% vs. 2.0%; OR 2.35 [95% confidence interval (CI) 2.10‐2.62]; P < 0.001), greater disability at discharge (34% vs. 26%; OR 1.53 [95% CI 1.46‐1.62]; P < 0.001), a longer length of stay (LOS) by 3.57 days, and higher cost of hospitalization by $25 400. In this database, patients with SLE and VTE were younger and of male sex. Also, African American race and a higher number of comorbidities were associated with an increased risk of VTE in patients with SLE.

Conclusion

VTE in hospitalized patients with SLE is associated with significantly higher inpatient mortality, greater disability at discharge, an increased LOS, and higher cost of hospitalization. This cross‐sectional study helps with quantifying the risk of VTE in hospitalized patients with SLE and provides information on the immense human and material cost this complication leads to. These data can be very useful in the development and implementation of appropriate prophylactic strategies in the high‐risk population with SLE.

Circulating platelet-neutrophil aggregates as risk factor for deep venous thrombosis

Background

Platelet-neutrophil aggregates (PNAs) are fundamental mechanisms linking hemostasis and inflammatory processes. Elevated level of PNAs have been reported in inflammatory diseases and coronary artery diseases. However, studies on the correlation between PNAs formation and deep venous thrombosis (DVT) are not available.

Methods

A total of 92 participants were involved in this study, including 32 cases with DVT and 60 cases without DVT. Blood samples coagulated by K2-EDTA or sodium citrate were prepared for blood cell count and blood smears. PNAs and platelet activation were measured using flow cytometry. The correlation between platelet activation level and PNAs level was analyzed by linear regression. Receiver operating characteristic (ROC) analysis was performed, assessing the prognostic performance of PNAs to predict potential risk of DVT occurrence.

Results

PNAs was found in the blood smears of patients with DVT. Significant increased level of PNAs was identified in DVT group (medium 8.43%, interquartile range [IQR] 4.11%–15.69%), compared with that in control group (5.16%, IQR 2.40–9.60, p<0.01). The DVT group also showed a dramatic elevated level of total platelet activation (medium 16.06%, IQR 6.04–22.05) vs. control group (11.26%, IQR 5.54–19.99, p<0.05). The PNAs level was correlated with total platelet activation (r2=0.58, p<0.0001). A significantly high odds ratio (OR) of DVT occurrence was identified when the level of PNAs was higher than 7.4% (OR 3.60, 95% confidence interval [CI] 1.463–8.838, p<0.01).

Conclusions

An elevated level of PNAs was associated with risk of DVT occurrence, which might be a suitable marker predicting DVT development.

The endothelial tumor suppressor p53 is essential for venous thrombus formation in aged mice

Venous thromboembolism (VTE) is a leading cause of morbidity and mortality in elderly people. Increased expression of tumor suppressor protein 53 (p53) has been implicated in vascular senescence. Here, we examined the importance of endothelial p53 for venous thrombosis and whether endothelial senescence and p53 overexpression are involved in the exponential increase of VTE with age. Mice with conditional, endothelial-specific deletion of p53 (End.p53-KO) and their wild-type littermates (End.p53-WT) underwent subtotal inferior vena cava (IVC) ligation to induce venous thrombosis. IVC ligation in aged (12-month-old) End.p53-WT mice resulted in higher rates of thrombus formation and greater mean thrombus size vs adult (12-week-old) End.p53-WT mice, whereas aged End.p53-KO mice were protected from vein thrombosis. Analysis of primary endothelial cells from aged mice or human vein endothelial cells after induction of replicative senescence revealed significantly increased early growth response gene-1 (Egr1) and heparanase expression, and plasma factor Xa levels were elevated in aged End.p53-WT, but not in End.p53-KO mice. Increased endothelial Egr1 and heparanase expression also was observed after doxorubicin-induced p53 overexpression, whereas p53 inhibition using pifithrin-α reduced tissue factor (TF) expression. Importantly, inhibition of heparanase activity using TF pathway inhibitor-2 (TFPI2) peptides prevented the enhanced venous thrombus formation in aged mice and restored it to the thrombotic phenotype of adult mice. Our findings suggest that p53 accumulation and heparanase overexpression in senescent endothelial cells are critically involved in mediating the increased risk of venous thrombosis with age and that heparanase antagonization may be explored as strategy to ameliorate the prothrombotic endothelial phenotype with age.

Risk of Recurrent Venous Thromboembolism After an Initial Episode: Risk Stratification and Implications for Long-term Treatment

PURPOSE OF REVIEW

Venous thromboembolism (VTE) is a common condition with significant associated morbidity and mortality. Recurrent VTE after an initial episode is a preventable medical condition. The following review discusses data supporting recurrence risk estimates after an initial VTE episode as well as treatment strategies to mitigate risk of recurrent VTE.

RECENT FINDINGS

This review particularly highlights methods for stratifying the risk of recurrent VTE and recent studies that have evaluated direct oral anticoagulants for the prevention of recurrent VTE. Risk assessment for VTE recurrence should guide anticoagulation duration. In patients who present with unprovoked VTE events, there remains a high risk of recurrence that is significantly mitigated with extended duration anticoagulation with either a vitamin K antagonist or direct oral anticoagulant.