Risk Factors for Elevated D-Dimer Levels in Patients with Gastrointestinal Tumors Treated with Endoscopic Submucosal Dissection

Endoscopic submucosal dissection (ESD) is almost always performed with a sedative because of the longer procedure times involved. The risk of post-ESD deep vein thrombosis (DVT) has been reported as relatively high, and D-dimer levels are sometimes elevated after ESD. This retrospective study evaluated factors affecting changes in D-dimer levels from before to after ESD to identify causes of elevated D-dimer levels after ESD. This retrospective analysis included 117 patients with gastrointestinal tumors resected using ESD. After excluding eight patients with pre-ESD levels of D-dimer >1.5 μg/mL, factors correlating with changes in D-dimer from before to after ESD were analyzed using logistic regression analysis in 109 patients. Sedation was accomplished primarily using midazolam, but, because the sedative effect of midazolam shows marked inter-individual variability, a "corrected midazolam dose" was determined by dividing the total midazolam dose by the initial dose to correct for inter-individual differences in the sedative effect of midazolam. This value was used as one potential explanatory variable in the subgroup analysis of the 103 patients who received midazolam. In the subgroup analysis using the corrected midazolam dose as an explanatory variable, only the corrected midazolam dose correlated with a change in D-dimer ≥1.0 μg/mL in multivariate analysis (odds ratio (OR) = 1.5, 95% confidence interval (CI) 0.43-0.95; p = 0.030). The corrected midazolam dose correlated with increases in post-ESD D-dimer levels. This potential relationship indicates that patients undergoing ESD and requiring extended sedation may be at increased risk of DVT.

Efficacy and safety of vena cava filters in preventing pulmonary embolism: A systematic review and meta-analysis

OBJECTIVES

To assess the treatment effectiveness of inferior vena cava filters (IVCF) versus non-IVCF for patients undergoing varies conditions.

METHODS

We systematically searched the databases to identify eligible RCTs from their inception up to 9/20/2020. The primary endpoint was pulmonary embolism (PE), while the secondary endpoints included deep-vein thrombosis (DVT), major bleeding, and all-cause mortality. The RRs with 95% CIs were applied as effect estimates for the treatment effectiveness of IVCF versus non-IVCF and calculated by using the random-effects model.

RESULTS

1,137 patients of 5 RCTs were enrolled. There were no significant differences between IVCF and non-IVCF for the risk of PE, major bleeding, and all-cause mortality, while the risk of DVT was significantly increased for patients treated with IVCF.

CONCLUSIONS

The use of IVCF did not yield any benefits on PE, major bleeding, and all-cause mortality risk for patients undergoing various conditions, while the risk of DVT was significantly increased for patients treated with IVCF.

Does follow-up D-dimer level help in predicting oxygenation status, ventilatory support requirement, lung fibrosis, and thromboembolic events in coronavirus disease 2019 pneumonia? A prospective observational study in a tertiary care setting in India

Introduction

Coronavirus disease 2019 (COVID-19) pneumonia is a heterogeneous disease with variable effects on lung parenchyma, airways, and vasculature, leading to long-term effects on lung functions.

Materials and Methods

This multicentric, prospective, observational, and interventional study included 1000 COVID-19 cases confirmed with reverse transcription-polymerase chain reaction. All cases were assessed with high-resolution computed tomography thorax, oxygen saturation, inflammatory marker as D-dimer at the entry point, and follow-up. Age, gender, comorbidity, use of bilevel positive airway pressure/noninvasive ventilation (BiPAP/NIV), and outcome as with or without lung fibrosis as per CT severity were key observations. In selected cases, we have performed lower limb venous Doppler and computed tomography (CT) pulmonary angiography to rule out deep-vein thrombosis (DVT) or pulmonary thromboembolism (PTE) respectively. Statistical analysis is performed by using Chi-square test.

Observations and Analysis

Age (<50 and >50 years) and gender (male vs. female) has a significant association with D-dimer level (P < 0.00001 and P < 0.010, respectively). CT severity score at the entry point with the D-dimer level has a significant correlation (P < 0.00001). The D-dimer level has a significant association with the duration of illness before hospitalization (P < 0.00001). Comorbidities have a significant association with D-dimer levels (P < 0.00001). D-dimer level has a significant association with oxygen saturation (P < 0.00001). BIPAP/NIV requirement has a significant association with the D-dimer level (P < 0.00001). Timing of BIPAP/NIV requirement during hospitalization has a significant association with D-dimer level (P < 0.00001). Follow-up D-dimer titer during hospitalization as compared to normal and abnormal to entry point level has a significant association with post-COVID lung fibrosis, DVT, and PTE (P < 0.00001).

Conclusions

D-dimer has documented a very crucial role in COVID-19 pneumonia in predicting the severity of illness and assessing response to treatment during hospitalization, and follow-up titers have a significant role in step-up or step-down interventions in a critical care setting.

Multidisciplinary care of the pregnant patient with or at risk for venous thromboembolism: a recommended toolkit from the Foundation for Women and Girls with Blood Disorders Thrombosis Subcommittee

The care of pregnant persons with/at risk of venous thromboembolism is complex and often challenging. Although guidelines have been published regarding the use of specific therapies, such as anticoagulants; in this population, none have provided guidance on how to coordinate multidisciplinary care of these patients. Here we provide an expert consensus on the role of various providers in the care of this patient population, as well as necessary resources and suggestions for best practices.

Predictable Risk Factors of Upper-Extremity Deep Venous Thrombosis in a Level I Trauma Center

Background

Venous thromboembolism is a common cause of morbidity and mortality in hospital patients, especially that of the lower extremities. Risk factors and diagnostic elements of upper-extremity deep-vein thrombosis (UEDVT) are poorly understood compared to those of the lower extremities. The primary objectives of this study were to identify predictive risk factors of secondary UEDVT.

Methods

This retrospective study included all nonpregnant patients aged >18 years who had undergone upper-extremity duplex scans to check for the presence of secondary UEDVT at Richmond University Medical Center from January 2014 to March 2020. Patients were stratified by presence or absence of UEDVT. Collected data points included patient demographics, comorbidities, central-line use, platelet count at time of scan, length of stay, and overall mortality. IBM 27.0 was used for all statistical analysis, with p<0.05 considered significant.

Results

A total of 1,009 upper extremity venous duplex studies were included. There were no significant differences in age, sex, race, or mean platelet levels between patients diagnosed with DVT and those without (p<0.05). After multinomial regression analysis, central venous catheter (CVC; 26.8% versus 78.5%, aOR 1.770, 95% CI 1.150–2.725; p<0.002), peripherally inserted central catheter (PICC) line (17.5% versus 82.5%, aOR3.254, 95% CI 1.997–5.304; p<0.001), hypertension (67.8% versus 28.8%, aOR 1.641, 95% CI 1.136–2.369; p<0.001), chronic kidney disease (CKD; 34.5% versus 65.5%, aOR 1.743, 95% CI 1.201–2.531; p<0.001), and malignancy (27.1% versus 74.6%, aOR 1.475, 95% CI 0.994–2.190; p<0.053) were found to be independent predictors of UEDVT.

Conclusion

Use of CVC or PICC line, preexisting diagnosis of hypertension, malignancy, and CKD were independent risk factors of UEDVT, while there was no significant correlation between increased platelet levels and UEDVT.

Efficacy and safety of non-vitamin K antagonist oral anticoagulants for venous thromboembolism: a meta-analysis

Objective

Several trials had compared the efficacy and safety between non-vitamin K antagonist oral anticoagulants and warfarin for acute venous thromboembolism, but the results were incomplete. This updated review comprehensively assessed the efficacy and safety of non-vitamin K antagonist oral anticoagulants for venous thromboembolism.

Design

Meta-analysis of randomised control trials. Six databases were searched from January 2000 to December 2018.

Setting

Adult patients had got non-vitamin K antagonist oral anticoagulants or warfarin for venous thromboembolism.

Participants

Randomised control trials that compared the efficacy and safety between non-vitamin K antagonist oral anticoagulants and warfarin.

Main outcome measures

The efficacy and safety of non-vitamin K antagonist oral anticoagulants .

Results

Seven studies involving 29,879 cases were included, among which 14,943 cases were assigned to non-vitamin K antagonist oral anticoagulants group and 14,936 cases to warfarin group. Meta-analysis showed that compared with warfarin, recurrent venous thromboembolism (odds ratio 0.94 [95% confidence interval 0.81 to 1.11]), death related to venous thromboembolism or fatal pulmonary embolism (odds ratio 1.00 [95% confidence interval 0.63 to 1.60]), symptomatic deep-vein thrombosis (odds ratio 0.88 [95% confidence interval 0.72 to 1.09]), symptomatic nonfatal pulmonary embolism (odds ratio 1.03 [(95% confidence interval 0.82 to 1.30]) and all deaths (odds ratio 0.92 [95% confidence interval 0.76 to 1.12]) are similar in non-vitamin K antagonist oral anticoagulants group, but major bleeding event (odds ratio 0.61 [95% confidence interval 0.50 to 0.75]) and clinically relevant non-major bleeding event (odds ratio [95% confidence interval 0.53 to 0.85]) are less in non-vitamin K antagonist oral anticoagulants group. .

Conclusions

For the treatment of venous thromboembolism, non-vitamin K antagonist oral anticoagulants is as effective as warfarin, and has a better safety profile than warfarin.

Venous Thromboembolism in Major Orthopedic Surgery

Venous thromboembolism (VTE) is one of the most important complications in orthopedic surgery. Deep-vein thrombosis occurs frequently after surgery but has few clinical symptoms. The emboli formed may cause pulmonary thromboembolism, which is associated with a high mortality rate. The cost of medical care is doubled when VTE develops after surgery. Thus, it is imperative to focus on preventing VTE after major orthopedic surgery. The prevention method should be selected after considering the balance between VTE risk and bleeding risk attributable to drug prophylaxis. Physical prophylaxis, drug prophylaxis, or both should be selected. When performing VTE prophylaxis, the risks and merits of prophylaxis must be made clear to patients.

Pedal Musculovenous Pump Activation Effectively Counteracts Negative Impact of Knee Flexion on Human Popliteal Venous Flow

Knee scooters are commonly used for mobility instead of other devices. However, passive popliteal venous flow impedance has been observed with knee scooter usage ostensibly as a result of deep knee flexion. This study aimed to characterize the magnitude of impact knee flexion has on popliteal venous flow in relation to the degree of knee flexion when walking boot immobilized. Furthermore, the countervailing effect of standardized pedal musculovenous pump (PMP) activation was observed. Popliteal venous diameter and flow metrics were assessed with venous ultrasonography in 24 healthy individuals. Straight leg, crutch, and knee scooter positioning while wearing a walking boot and non-weight-bearing were compared. Flow was assessed with muscles at rest and with PMP activation. Of 24 participants, 16 (67%) were female. Twelve limbs (50%) were right sided. The mean age was 21.9 (SD = 3.0) years, and the mean body mass index was 21.9 (SD 1.9) kg/m². Observer consistencies were excellent (intraclass correlation range = 0.93 to 0.99). No significant differences in mean vessel diameter, time-averaged mean velocity, and total volume flow occurred (all P > .01). Corresponding knee flexion effect sizes were small (range = -0.04 to -0.26). A significant decrease (-24%) in active median time-averaged peak velocity occurred between upright and crutch positions (20.89 vs 15.92 cm/s; P < .001) with a medium effect size (-0.51). PMP activation increased all flow parameters (all P < .001), and effect sizes were comparatively larger (>0.6) across all knee flexion positions.Clinical Significance: Knee flexion has a small to medium impact on popliteal venous return in healthy patients. Active toe motion effectively counters the negative effects of gravity and knee flexion when the ankle is immobilized.Levels of Evidence: Therapeutic, Level IV.

Current Challenges in Diagnosis of Venous Thromboembolism

In patients with suspected venous thromboembolism, the goal is to accurately and rapidly identify those with and without thrombosis. Failure to diagnose venous thromboembolism (VTE) can lead to fatal pulmonary embolism (PE), and unnecessary anticoagulation can cause avoidable bleeding. The adoption of a structured approach to VTE diagnosis, that includes clinical prediction rules, D-dimer testing and non-invasive imaging modalities, has enabled rapid, cost-effective and accurate VTE diagnosis, but problems still persist. First, with increased reliance on imaging and widespread use of sensitive multidetector computed tomography (CT) scanners, there is a potential for overdiagnosis of VTE. Second, the optimal strategy for diagnosing recurrent leg deep venous thrombosis remains unclear as is that for venous thrombosis at unusual sites. Third, the conventional diagnostic approach is inefficient in that it is unable to exclude VTE in high-risk patients. In this review, we outline pragmatic approaches for the clinician faced with difficult VTE diagnostic cases. In addition to discussing the principles of the current diagnostic framework, we explore the diagnostic approach to recurrent VTE, isolated distal deep-vein thrombosis (DVT), pregnancy associated VTE, subsegmental PE, and VTE diagnosis in complex medical patients (including those with impaired renal function).

Single-Drug Approach with Edoxaban is Effective for Resolving Non-Acute Cancer-Associated Venous Thrombosis: A Single-Arm Retrospective Analysis

Recently, cancer-related venous thromboembolism (VTE) has been termed "cancer-associated thrombosis (CAT)" and is the focus of current research. We retrospectively investigated the efficacy of a single-drug approach with edoxaban for the treatment of non-acute CAT. Thirty-two non-acute CAT patients who received edoxaban were analyzed. The primary endpoint of this analysis was the thrombus disappearance rate at the first evaluation. Secondary endpoints included progression/recurrence of VTE, major bleeding, and D-dimer levels. The thrombus disappearance rate was 62.5%. Therefore, the null hypothesis for the primary endpoint (thrombus disappearance rate of ≤32.0%) was rejected (p = 0.00038) based on the rate of the previous study as the historical control. Recurrent VTE and major bleeding occurred in two patients each. After the start of treatment with edoxaban, a significant difference in D-dimer levels was observed (p = 0.00655). We demonstrated that a single-drug approach with edoxaban is a potential treatment option for non-acute CAT.

Postoperative Anaemia Is a Risk Factor for Bleeding-Related Event in Thromboprophylaxis Using Fondaparinux Sodium Injection after Total Knee or Hip Arthroplasty

Bleeding is a life-threating side effect of thromboprophylaxis with fondaparinux sodium (FPX) injection. The purpose of this retrospective study was to assess the risk factor for bleeding-related event following thromboprophylaxis with FPX after total knee arthroplasty (TKA) or total hip arthroplasty (THA). Adult patients undergoing TKA or THA at a single university hospital were administered FPX for thromboprophylaxis by subcutaneous injection of 1.5 or 2.5 mg per day. The risk factor for bleeding-related event was identified by propensity score-adjusted multivariate logistic analysis, and survival analysis was performed retrospectively in consideration of the identified risk factors. Two hundred and twenty-six patients who underwent TKA (n = 62) or THA (n = 164) were enrolled. Anaemia on postoperative day (POD) 1 was identified as a risk factor for bleeding-related event (odds ratio: 3.75, 95% confidence interval: 1.02-24.5, p = 0.04). Eighty of 226 patients were selected using a propensity score matching and patients with anaemia on POD1 in this population had a significantly higher incidence of bleeding-related event than those without anaemia (p = 0.0016, Ghen-Breslow-Wilcoxon test; p = 0.0015, log-rank test). These results suggest that anaemia on POD1 is an independent risk factor for bleeding-related event following thromboprophylaxis with FPX after TKA or THA.

Accuracy of three-point compression ultrasound for the diagnosis of proximal deep-vein thrombosis in emergency department

Background:

This study aimed to assess the accuracy of three-point compression ultrasonography (3PCUS) performed for the diagnosis of proximal deep-vein thrombosis (DVT) in Emergency Department (ED) compared with the results of duplex US (DUS) (whole-leg compression ultrasound).

Materials and Methods:

The current prospective cross-sectional study with diagnostic test assessment was conducted on adult patients who were referred to the ED of a general teaching hospital in Shiraz, southern part of Iran (September 2016–May 2017), suspected of lower-extremity DVT, using a convenience sampling. The results of 3PCUS performed by ED residents were compared with the results of DUS performed by the radiology residents, which was considered as a criterion standard.

Results:

A total of 240 patients were enrolled, with a mean (standard deviation) age of 59.46 (16.58). 3PCUS has a sensitivity and a specificity of 100% (95% confidence interval [CI], 96.55%–100%) and 93.33% (95% CI, 87.72%–96.91%), respectively, in comparison with DUS (whole-leg compression ultrasound). Negative predictive value and positive predictive value were 100% and 92.11% (95% CI, 86.12%–95.64%), respectively, with an accuracy of 96.25% (95% CI, 93%–98.27%).

Conclusion:

The results of this study showed that 3PCUS of the lower extremities with a portable US machine, performed by the ED's residents, can accurately identify the presence or absence of lower-extremity DVT.

Improving fibrinolysis in venous thromboembolism: impact of fibrin structure

Introduction. Fibrinolysis is of key importance in maintaining vessel patency. Impaired fibrinolysis associated with more compact fibrin structure has been shown in patients with venous thromboembolism (VTE), including deep-vein thrombosis and pulmonary embolism (PE). Currently, recombinant or modified plasminogen activators are the only commonly available thrombolytic agents. However, they are fraught with side effects and suboptimal effectiveness. Areas covered. Based on the available literature, the current evidence linking fibrinolysis with VTE and potential therapeutic targets among fibrinolysis proteins are presented. Expert opinion. Prolonged clot lysis time has been reported as a new predictor of first-time and recurrent VTE, including PE. Anticoagulant therapy, including non-vitamin K antagonist oral anticoagulants, has a favorable impact on fibrinolysis in VTE patients. Several VTE risk factors are also related to lower efficiency of fibrinolysis and their treatment improve fibrinolysis, in part by alterations to fibrin properties. There is an increasing number of studies aiming at developing novel profibrinolytic therapeutic agents for treatment of VTE patients, mostly targeting the antifibrinolytic proteins, i.e. antiplasmin, plasminogen activator inhibitor-1 and thrombin-activatable fibrinolysis inhibitor.

Patient Management Strategies and Long-Term Outcomes in Isolated Distal Deep-Vein Thrombosis versus Proximal Deep-Vein Thrombosis: Findings from XALIA

Background  Overall, 30 to 50% of lower-limb deep-vein thrombosis (DVT) cases are isolated distal DVT (IDDVT). The recurrent venous thromboembolism (VTE) risk is unclear, leaving uncertainty over optimal IDDVT treatment. We present data on patients with IDDVT and proximal DVT (PDVT) from the prospective, noninterventional XALIA study of rivaroxaban for acute and extended VTE treatment.

Methods  Patients aged ≥18 years scheduled to receive ≥3 months' anticoagulation with rivaroxaban or standard anticoagulation were eligible, with follow-up for ≥12 months. We describe baseline characteristics, management strategies, and incidence proportions of VTE recurrence, major bleeding, and all-cause mortality in patients with IDDVT or PDVT, with or without distal vein involvement.

Findings  Overall, 1,004 patients with IDDVT and 3,098 with PDVT were enrolled; 641 (63.8%) and 1,683 (54.3%) received rivaroxaban, respectively. Patients with IDDVT were younger and had lower incidences of renal impairment, cancer, and unprovoked VTE than those with PDVT. On-treatment recurrence incidences for IDDVT versus PDVT were 1.0 versus 2.4% (adjusted hazard ratio [HR]: 0.56; 95% confidence interval [CI]: 0.29–1.08), and incidences posttreatment cessation were 1.1 versus 2.1% (adjusted HR: 0.65; 95% CI: 0.32–1.35), respectively. On-treatment major bleeding incidences were 0.9 versus 1.4% and mortality was 0.8 versus 2.2%, respectively. Median treatment duration in patients with IDDVT was shorter than in those with PDVT (102 vs. 192 days, respectively).

Interpretation  Patients with IDDVT had fewer comorbidities and were more frequently treated with rivaroxaban than those with PDVT. On-treatment and posttreatment recurrences were less frequent in patients with IDDVT.

Trial registration number:  NCT01619007.

A Test in Context: D-Dimer

D-dimer is a soluble fibrin degradation product that results from ordered breakdown of thrombi by the fibrinolytic system. Numerous studies have shown that D-dimer serves as a valuable marker of activation of coagulation and fibrinolysis. Consequently, D-dimer has been extensively investigated for the diagnosis of venous thromboembolism (VTE) and is used routinely for this indication. In addition, D-dimer has been evaluated for determining the optimal duration of anticoagulation in VTE patients, for diagnosing and monitoring disseminated intravascular coagulation, and as an aid in the identification of medical patients at high risk for VTE. Thus, quantification of D-dimer levels serves an important role in guiding therapy. This review: 1) describes how D-dimer is generated; 2) reviews the assays used for its detection; and 3) discusses the role of D-dimer determination in these various conditions.

Cost-effectiveness analysis of rivaroxaban for treatment and secondary prevention of venous thromboembolism in the Netherlands

BACKGROUND

Until recently, standard treatment of venous thromboembolism (VTE) concerned a combination of short-term low-molecular-weight heparin (LMWH) and long-term vitamin-K antagonist (VKA). Risk of bleeding and the requirement for regular anticoagulation monitoring are, however, limiting their use. Rivaroxaban is a novel oral anticoagulant associated with a significantly lower risk of major bleeds (hazard ratio = 0.54, 95% confidence interval = 0.37-0.79) compared to LMWH/VKA therapy, and does not require regular anticoagulation monitoring.

AIMS

To evaluate the health economic consequences of treating acute VTE patients with rivaroxaban compared to treatment with LMWH/VKA, viewed from the Dutch societal perspective.

METHODS

A life-time Markov model was populated with the findings of the EINSTEIN phase III clinical trial to analyze cost-effectiveness of rivaroxaban therapy in treatment and prevention of VTE from a Dutch societal perspective. Primary model outcomes were total and incremental quality-adjusted life years (QALYs), as well as life expectancy and costs.

RESULTS

Over a patient's lifetime, rivaroxaban was shown to be dominant, with health gains of 0.047 QALYs and cost savings of €304 compared to LMWH/VKA therapy. Dominance was robustly present in all sensitivity analyses. Major drivers of the differences between the two treatment arms were related to anticoagulation monitoring (medical costs, travel costs, and loss of productivity) and the occurrence of major bleeds.

CONCLUSION

Rivaroxaban treatment of patients with venous thromboembolism results in health gains and cost savings compared to LMWH/VKA therapy. This conclusion holds for the Dutch setting, both for the societal perspective, as well as the healthcare perspective.

Venous thromboembolism: Past, present and future

Venous thromboembolism (VTE), the third most frequent acute cardiovascular syndrome, is associated with a considerable disease burden which continues to grow along with the longer life expectancy of the population worldwide. In the past century, parenteral heparin prophylaxis was established for hospitalised patients at elevated risk of VTE. More recently, non-vitamin K antagonist oral anticoagulants (NOACs) with a direct inhibiting effect on factor Xa or thrombin, underwent extensive testing in clinical trials and have been approved for patients undergoing hip or knee replacement. Clinical investigation is ongoing in further areas of thromboprophylaxis, including medical prophylaxis in patients and high-risk situations in the outpatient setting. The diagnostic approach to suspected VTE is now based on advanced imaging techniques and robust diagnostic algorithms which ensure high sensitivity and specificity. Nevertheless, the role of clinical, or pre-test, probability assessment remains crucial to avoid overdiagnosis and treatment errors. Advances in reperfusion strategies, along progressive establishment of the NOACs as the new standard of anticoagulation treatment, have simplified the management of VTE, improving outcomes and particularly safety. While new molecular targets for anticoagulation are being investigated in the quest to further reduce bleeding risk, adjusting the initial regimen to the patient's risk and finding the optimal duration of anticoagulation after an index VTE event will be some of the top priorities in the years to come. Importantly, and in parallel to new drugs and technical advances in imaging, incentives such as hospital accreditation and funding based on evidence-based practice need to be implemented to increase guideline adherence.

Occult cancer in patients with deep-vein thrombosis in a general hospital at Mexico City: A pilot study

Background:

We aimed to explore the frequency of occult cancer in patients with deep-vein thrombosis (DVT) at a general hospital in Mexico City.

Materials and Methods:

From March 2012 to February 2015, all patients with primary DVT of lower extremities attended in the emergency department of our hospital were studied. Initially, all patients were evaluated with clinical history, physical examination, basic laboratories, abdominal ultrasound, chest X-ray, and duplex venous ultrasonography. In a case-by-case approach, if necessary, computed tomography, endoscopy, colonoscopy, and tumor markers were done.

Results:

From 182 patients with primary DVT, 30 (16.5%) presented occult cancer: Thirteen males and 17 females, with an average age of 61 years. In males, prostate cancer prevailed (6/13, 46%); meanwhile, in females, pelvic gynecologic cancers predominated (7/17, 41%).

Conclusion:

Our results suggest that in Mexican patients with primary DVT, occult cancer is frequent.

Efficacy and safety of extended thromboprophylaxis for medically ill patients. A meta-analysis of randomised controlled trials

Compelling evidence suggests that the risk of pulmonary embolism (PE) and deep-vein thrombosis (DVT) persists after hospital discharge in acutely-ill medical patients. However, no studies consistently supported the routine use of extended-duration thromboprophylaxis (ET) in this setting. We performed a meta-analysis to assess efficacy and safety of ET in acutely-ill medical patients. Efficacy outcome was defined by the prevention of symptomatic DVT, PE, venous thromboembolism (VTE) and VTE-related mortality. Safety outcome was the occurrence of major bleeding (MB) and fatal bleeding (FB). Pooled odds ratios (ORs) and 95 % confidence intervals (95 %CI) were calculated for each outcome using a random effects model. Four RCTs for a total of 28,105 acutely-ill medical patients were included. ET was associated with a significantly lower risk of DVT (0.3 % vs 0.6 %, OR 0.504, 95 %CI: 0.287-0.885) and VTE (0.5 % vs 1.0 %, OR: 0.544, 95 %CI: 0.297-0.997); a non-significantly lower risk of PE (0.3 % vs 0.4 %, OR 0.633, 95 %CI: 0.388-1.034) and of VTE-related mortality (0.2 % vs 0.3 %, OR 0.687, 95 %CI: 0.445-1.059) and with a significantly higher risk of MB (0.8 % vs 0.4 %, OR 2.095, 95 %CI: 1.333-3.295). No difference in FB was found (0.06 % vs 0.03 %, OR 1.79, 95 %CI: 0.384-8.325). The risk benefit analysis showed that the NNT for DVT was 339, for VTE was 239, and the NNH for MB was 247. Results of our meta-analyses focused on clinical important outcomes did not support a general use of antithrombotic prophylaxis beyond the period of hospitalization in acutely-ill medical patients.

Global Anticoagulant Registry in the Field - Venous Thromboembolism (GARFIELD-VTE). Rationale and design

Venous thromboembolism (VTE) is a common disorder associated with significant rates of morbidity and mortality. VTE management aims to reduce mortality, the risks of recurrence, and long-term complications. VTE treatment is evolving with the introduction of non-vitamin K antagonist anticoagulants (NOACs). The Global Anticoagulant Registry in the FIELD - Venous Thromboembolism (GARFIELD-VTE) is a prospective, multicentre, observational study that will enrol 10,000 patients treated for acute VTE from ~500 sites in 28 countries. Identified sites reflect the diversity of care settings, including hospital and outpatient settings. Patients will be managed according to local practices and followed for at least three years. The primary objective is to determine the extent to which VTE treatment varies in the real-world setting and to assess the impact of such variability on clinical and economic outcomes. Evolving patterns of care will be captured using two sequential cohorts. The GARFIELD-VTE registry will provide insights into the evolving global treatment patterns for VTE, both deep-vein thrombosis and pulmonary embolism. By enrolling patients from diverse care settings, the registry will provide information on adherence to national and international guidelines, identify good practice as well as treatment deficiencies, and relate patient outcomes to clinical management. The incidence of death, recurrent VTE, bleeding, post-thrombotic syndrome and chronic thromboembolic pulmonary hypertension will be documented. By capturing information during and after anticoagulation treatment, the registry will not only define aspects of the natural history of VTE, but also its economic and societal impact at a regional and global level.

Cell-based laboratory evaluation of coagulation activation by antineoplastic drugs for the treatment of lymphoid tumors

Objectives:

Combining vorinostat, L-asparaginase, and doxorubicin (Dox) led to improved response rates in the treatment of lymphoid tumors. However, deep-vein thrombosis has been noted as one of the most serious side effects with these drugs, and how these regimens cause deep-vein thrombosis is unclear.

Methods:

We investigated the procoagulant effects of vorinostat, L-asparaginase, and doxorubicin in lymphoid tumors, focusing on tissue factor, phosphatidylserine, and antithrombin. The human vascular endothelial cell line EAhy926 as well as the lymphoid neoplastic cell lines HUT78 (cutaneous T-cell lymphoma), Molt4 (acute T-lymphoblastic leukemia), and Ramos (Burkitt lymphoma) were employed to investigate these procoagulant effects.

Results:

Vorinostat, L-asparaginase, and doxorubicin induced exposure of phosphatidylserine and procoagulant activity on the surface of lymphoid tumor cells. Vorinostat and doxorubicin also induced phosphatidylserine exposure and increased procoagulant activity on EAhy926 cells. Expression of tissue factor antigen was induced by doxorubicin on the surface of each type of cells, whereas expression of tissue factor mRNA was unchanged. Secretion of antithrombin from HepG2 cells was reduced only by L-asparaginase.

Conclusion:

These data suggest that vorinostat and doxorubicin may induce procoagulant activity in vessels through apoptosis of tumor cells and through phosphatidylserine exposure and/or tissue factor expression on vascular endothelial cells. L-asparaginase may induce a thrombophilic state by reducing the secretion of anticoagulant proteins such as antithrombin. The laboratory methods described here could be useful to evaluate the procoagulant effects of antineoplastic drugs.

The MARINER trial of rivaroxaban after hospital discharge for medical patients at high risk of VTE. Design, rationale, and clinical implications

Hospital-associated venous thromboembolism (VTE) is a leading cause of premature death and disability worldwide. Evidence-based guidelines recommend that anticoagulant thromboprophylaxis be given to hospitalised medical patients at risk of VTE, but suggest against routine use of thromboprophylaxis beyond the hospital stay. The MARINER study is a randomised, double-blind, placebo-controlled trial to evaluate the efficacy and safety of thromboprophylaxis using rivaroxaban, begun at hospital discharge and continued for 45 days, for preventing symptomatic VTE in high-risk medical patients. Eligible patients are identified using the International Medical Prevention Registry on Venous Thromboembolism (IMPROVE VTE) risk score, combined with a laboratory test, D-dimer. The rivaroxaban regimen is 10 mg once daily for patients with CrCl ≥ 50 ml/min, or 7.5 mg once daily for patients with CrCl ≥ 30 ml/min and < 50 ml/min. The primary efficacy outcome is the composite of symptomatic VTE (lower extremity deep-vein thrombosis and non-fatal pulmonary embolism) and VTE-related death. The principal safety outcome is major bleeding. A blinded clinical events committee adjudicates all suspected outcome events. The sample size is event-driven with an estimated total of 8,000 patients to acquire 161 primary outcome events. Study design features that distinguish MARINER from previous and ongoing thromboprophylaxis trials in medically ill patients are: (i) use of a validated risk assessment model (IMPROVE VTE) and D-dimer determination for identifying eligible patients at high risk of VTE, (ii) randomisation at the time of hospital discharge, (iii) a 45-day treatment period and (iv) restriction of the primary efficacy outcome to symptomatic VTE events.

A primary intravascular synovial sarcoma causing deep-vein thrombosis and pulmonary embolism in a 20-year-old woman

Primary intravascular synovial sarcoma is a rare malignancy with only a few cases documented in the literature. On presentation, this tumour usually resembles a deep venous thrombosis (dvt) or pulmonary embolism (pe). Here, we report the case of a 20-year-old woman complaining of shortness of breath who had a history of dvt 6 weeks before presentation at our institution. Vascular ultrasound detected a suspicious mass in the right groin, which was identified as a monophasic synovial sarcoma by surgical biopsy. The tumour extended from the right superficial femoral vein into the common iliac vein, profound femoral vein, and great saphenous vein. It caused pe with near-total occlusion of the right pulmonary artery. After initial treatment on the cardiac intensive care unit, the patient was referred to the oncology department for neoadjuvant radiochemotherapy with doxorubicin-ifosfamide according to the Interdisziplinäre Arbeitsgemeinschaft Weichteilsarkome [Interdisciplinary AG Sarcomas] protocol and surgical resection of the tumour. No signs of tumour recurrence were found during the subsequent course of the disease, but the patient died from treatment complications approximately 15 months after initial presentation. This case underlines the importance of screening for malignancies even in young patients presenting with dvt or pe. We also recommend whole-leg compression ultrasonography in patients with suspected dvt or pe (as opposed to venography or simple four-point ultrasound examination in the groin and popliteal fossa) to detect possible underlying causes for thrombosis.

Population pharmacokinetics of edoxaban in patients with symptomatic deep-vein thrombosis and/or pulmonary embolism--the Hokusai-VTE phase 3 study

AIMS

This study characterized the population pharmacokinetics of edoxaban in patients with symptomatic deep-vein thrombosis and/or pulmonary embolism in the Hokusai-VTE phase 3 study. The impact of the protocol-specified 50% dose reductions applied to patients with body weight ≤ 60 kg, creatinine clearance (CL(cr)) of 30 to 50 ml min(-1) or concomitant P-glycoprotein inhibitor on edoxaban exposure was assessed using simulations.

METHODS

The sparse data from Hokusai-VTE, 9531 concentrations collected from 3707 patients, were pooled with data from 13 phase 1 studies. In the analysis, the covariate relationships used for dose reductions were estimated and differences between healthy subjects and patients as well as additional covariate effects of age, race and gender were explored based on statistical and clinical significance.

RESULTS

A linear two-compartment model with first order absorption preceded by a lag time best described the data. Allometrically scaled body weight was included on disposition parameters. Apparent clearance was parameterized as non-renal and renal. The latter increased non-linearly with increasing CL(cr). Compared with healthy volunteers, inter-compartmental clearance and the CL(cr) covariate effect were different in patients (+64.6% and +274%). Asian patients had a 22.6% increased apparent central volume of distribution. The effect of co-administration of P-glycoprotein inhibitors seen in phase 1 could not be confirmed in the phase 3 data. Model-based simulations revealed lower exposure in dose-reduced compared with non-dose-reduced patients.

CONCLUSIONS

The adopted dose-reduction strategy resulted in reduced exposure compared with non-dose-reduced, thereby overcompensating for covariate effects. The clinical impact of these differences on safety and efficacy remains to be evaluated.

Thrombosis in pregnancy and maternal outcomes

Pregnancy increases the risk of thrombosis four- to five-fold. Seventy-five to eighty percent of pregnancy-related thrombotic events are venous and twenty to -twenty-five percent are arterial. The main reason for the increased risk is hypercoagulability. Women are hypercoagulable because they have evolved so that they are protected against the bleeding challenges of pregnancy, miscarriage, or childbirth. Both genetic and acquired risk factors can further increase the risk of thrombosis. The maternal consequences of thrombosis of pregnancy include permanent vascular damage, disability, and death. While the maternal outcomes of thrombosis can be modified by anticoagulation therapy, management of thrombosis during pregnancy is the subject of another paper in this issue (see paper by B. Konkle). This review will focus on the epidemiology, pathophysiology, risk factors, and maternal consequences of thrombosis in pregnancy.

Divergent effects of Tlr9 deletion in experimental late venous thrombosis resolution and vein wall injury

Deep-vein thrombosis (DVT) resolves via a sterile inflammatory response. Defining the inflammatory response of DVT may allow for new therapies that do not involve anticoagulation. Previously, we have shown that Toll-like receptor 9 (Tlr9) gene deleted mice had impaired venous thrombosis (VT) resolution. Here, we further characterise the role of Tlr9 signalling and sterile inflammation in chronic VT and vein wall responses. First, we found a human precedent exists with Tlr9+ cells present in chronic post thrombotic intraluminal tissue. Second, in a stasis VT mouse model, endogenous danger signal mediators of uric acid, HMGB-1, and neutrophil extracellular traps marker of citrullinated histone-3 (and extracellular DNA) were greater in Tlr9-/- thrombi as compared with wild-type (WT), corresponding with larger VT at 8 and 21 days. Fewer M1 type (CCR2+) monocyte/macrophages (MØ) were present in Tlr9-/- thrombi than WT controls at 8 days, suggesting an impaired inflammatory cell influx. Using bone marrow-derived monocyte (BMMØ) cell culture, we found decreased fibrinolytic gene expression with exposure to several endogenous danger signals. Next, adoptive transfer of cultured Tlr9+/+ BMMØ to Tlr9-/- mice normalised VT resolution at 8 days. Lastly, although the VT size was larger at 21 days in Tlr9-/- mice and correlated with decreased endothelial antigen markers, no difference in fibrosis was found. These data suggest that Tlr9 signalling in MØ is critical for later VT resolution, is associated with necrosis clearance, but does not affect later vein wall fibrosis. These findings provide insight into the Tlr9 MØ mechanisms of sterile inflammation in this disease process.

Acute phase treatment of VTE: Anticoagulation, including non-vitamin K antagonist oral anticoagulants

The acute phase of venous thromboembolism (VTE) treatment focuses on the prompt and safe initiation of full-dose anticoagulation to decrease morbidity and mortality. Immediate management consists of resuscitation, supportive care, and thrombolysis for patients with haemodynamically significant pulmonary embolism (PE) or limb-threatening deep-vein thrombosis (DVT). Patients with contraindications to anticoagulants are considered for vena cava filters. Disposition for the acute treatment of VTE is then considered based on published risk scores and the patient's social status, as the first seven days carries the highest risk for VTE recurrence, extension and bleeding due to anticoagulation. Next, a review of: immediate and long-term bleeding risk, comorbidities (i. e. active cancer, renal failure, obesity, thrombophilia), medications, patient preference, VTE location and potential for pregnancy should be undertaken. This will help determine the most suitable anticoagulant for immediate treatment. The non-vitamin K antagonist oral anticoagulants (NOACs), including the factor Xa inhibitors apixaban, edoxaban and rivaroxaban as well as the direct-thrombin inhibitor dabigatran, are increasing the convenience of and options available for VTE treatment. Current options for immediate treatment include low-molecular-weight heparin (LMWH), unfractionated heparin (UFH), fondaparinux, apixaban, or rivaroxaban. LMWH or UFH may be continued as monotherapy or transitioned to treatment with a VKA, dabigatran or edoxaban. This review describes the upfront treatment of VTE and the evolving role of NOACs in the contemporary management of VTE.

Edoxaban, a Novel Oral Factor Xa Inhibitor

OBJECTIVE

To evaluate the current literature and potential clinical role of edoxaban (Savaysa) for stroke prevention in nonvalvular atrial fibrillation (NVAF) and treatment of deep-vein thrombosis and pulmonary embolism.

DATA SOURCES

A PubMed and Cochrane Central Register of Controlled trials search was conducted in February 2015 using the search terms edoxaban (ordu-176b) and atrial fibrillation, deep vein thrombosis, pulmonary embolism, or venous thromboembolism. Bibliographies of all retrieved articles were reviewed. All references included were published between 1998 and 2015.

STUDY SELECTION/DATA EXTRACTION

All studies that included humans and contained data describing the use of edoxaban for either stroke prevention in patients with NVAF or the treatment of venous thromboembolism (VTE) were reviewed.

DATA SYNTHESIS

Edoxaban is a target-specific oral anticoagulant, specifically a factor Xa inhibitor. It has been studied in 4 major randomized controlled trials for the prevention of stroke and systemic embolism in patients with NVAF. One randomized controlled trial was conducted for the treatment of VTE. Edoxaban demonstrated noninferiority of the primary efficacy end point compared with warfarin for both approved indications. The most common adverse effect is bleeding, similar to other anticoagulants. A dosing limitation exists related to patients treated for NVAF with creatinine clearance >95 mL/min; these patients experienced decreased efficacy.

CONCLUSIONS

Edoxaban is a safe and effective anticoagulant to reduce the risk of stroke in patients with NVAF and for the treatment of VTE.

Association between pneumococcal pneumonia and venous thromboembolism in hospitalized patients: A nationwide population-based study

BACKGROUND AND OBJECTIVES

This was a nationwide population-based retrospective cohort study to investigate the risk of developing deep-vein thrombosis (DVT) and pulmonary embolism (PE) in patients with a pneumococcal pneumonia.

METHODS

We analysed data from 1998 to 2010 from the Taiwan National Health Insurance Database. The follow-up period was extended to the end of 2011. We identified patients with pneumococcal pneumonia and selected a comparison cohort matched for age, sex and diagnosis year at a ratio of one pneumococcal pneumonia patient to four control patients. We analysed the risks of DVT and PE by using Cox proportional hazards regression models, including gender, age and comorbidities.

RESULTS

In total, 18,928 pneumococcal pneumonia patients and 75,712 controls were included in the study. The risks of developing DVT and PE were 1.78-fold (95% CI: 1.39-2.28) and 1.97-fold (95% CI: 1.43-2.72), respectively, in patients with pneumococcal pneumonia compared to the control cohort after adjusting for age, gender and comorbidities. The increased risks of DVT and PE were significant in patients who exhibited any comorbidity. The incidences of DVT and PE were highest in the first 4 weeks after pneumonia and remained slightly elevated from 13 weeks to 2 years after acute infection.

CONCLUSION

Pneumococcal pneumonia should be considered a risk factor for DVT and PE, even after the patient has recovered from the acute infection.

Clinical challenges in patients with cancer-associated thrombosis: Canadian expert consensus recommendations

Venous thromboembolism is a common complication in cancer patients, and thromboembolism is the second most common cause of death after cancer progression. A number of clinical practice guidelines provide recommendations for the management of cancer-associated thrombosis. However, the guidelines lack recommendations covering commonly encountered clinical challenges (for example, thrombocytopenia, recurrent venous thromboembolism, etc.) for which little or no evidence exists. Accordingly, recommendations were developed to provide expert guidance to medical oncologists and other health care professionals caring for patients with cancer-associated thrombosis. The current expert consensus was developed by a team of 21 clinical experts. For each identified clinical challenge, the literature in medline, embase, and Evidence Based Medicine Reviews was systematically reviewed. The quality of the evidence was assessed, summarized, and graded. Consensus statements were generated, and the experts voted anonymously using a modified Delphi process on their level of agreement with the various statements. Statements were progressively revised through separate voting iterations and were then finalized. Clinicians using these recommendations and suggestions should tailor patient management according to the risks and benefits of the treatment options, patient values and preferences, and local cost and resource allocations.

Whole blood gene expression profiles distinguish clinical phenotypes of venous thromboembolism

INTRODUCTION

Recurrent venous thromboembolism (VTE) occurs infrequently following a provoked event but occurs in up to 30% of individuals following an initial unprovoked event. There is limited understanding of the biological mechanisms that predispose patients to recurrent VTE.

OBJECTIVES

To identify whole blood gene expression profiles that distinguished patients with clinically distinct patterns of VTE.

PATIENTS/METHODS

We studied 107 patients with VTE separated into 3 groups: (1) 'low-risk' patients had one or more provoked VTE; (2) 'moderate-risk' patients had a single unprovoked VTE; (3) 'high-risk' patients had ≥2 unprovoked VTE. Each patient group was also compared to twenty-five individuals with no personal history of VTE. Total RNA from whole blood was isolated and hybridized to Illumina HT-12V4 Beadchips to assay whole genome expression.

RESULTS

Using class prediction analysis, we distinguished high-risk patients from low-risk patients and healthy controls with good receiver operating curve characteristics (AUC=0.81 and 0.84, respectively). We also distinguished moderate-risk individuals and low-risk individuals from healthy controls with AUC's of 0.69 and 0.80, respectively. Using differential expression analysis, we identified several genes previously implicated in thrombotic disorders by genetic analyses, including SELP, KLKB1, ANXA5, and CD46. Protein levels for several of the identified genes were not significantly different between the different groups.

CONCLUSION

Gene expression profiles are capable of distinguishing patients with different clinical presentations of VTE, and genes relevant to VTE risk are frequently differentially expressed in these comparisons.

Atrial fibrillation associated with increased risk of venous thromboembolism. A population-based cohort study

Whether atrial fibrillation (AF) is associated with an increased risk of venous thromboembolism (VTE) remains controversial. From Longitudinal Health Insurance Database 2000 (LHID2000), we identified 11,458 patients newly diagnosed with AF. The comparison group comprised 45,637 patients without AF. Both cohorts were followed up to measure the incidence of deep-vein thrombosis (DVT) and pulmonary embolism (PE). Univariable and multivariable competing-risks regression model and Kaplan-Meier analyses with the use of Aelon-Johansen estimator were used to measure the differences of cumulative incidences of DVT and PE, respectively. The overall incidence rates (per 1,000 person-years) of DVT and PE between the AF group and non-AF groups were 2.69 vs 1.12 (crude hazard ratio [HR]= 1.92; 95 % confidence interval [CI] = 1.54-2.39), 1.55 vs 0.46 (crude HR = 2.68; 95 % CI = 1.97-3.64), respectively. The baseline demographics indicated that the members of the AF group demonstrated a significantly older age and higher proportions of comorbidities than non-AF group. After adjusting for age, sex, and comorbidities, the risks of DVT and PE remained significantly elevated in the AF group compared with the non-AF group (adjusted HR = 1.74; 95 %CI = 1.36-2.24, adjusted HR = 2.18; 95 %CI = 1.51-3.15, respectively). The Kaplan-Meier curve with the use of Aelon-Johansen estimator indicated that the cumulative incidences of DVT and PE were both more significantly elevated in the AF group than in the non-AF group after a long-term follow-up period (p<0.01). In conclusion, the presence of AF is associated with increased risk of VTE after a long-term follow-up period.

Association of deep-vein thrombosis (DVT) with missed doses of prophylactic antithrombotic medications in ICU patients: a case-control study

BACKGROUND

Medications for prevention of venous thromboembolism (VTE) are routinely prescribed in critically ill patients.

OBJECTIVE

To identify any association between missed doses of VTE prophylaxis medications and acute, in-hospital deep-vein thrombosis (DVT).

METHODS

Case-control study in hospitalized adult patients at high risk for developing VTE, defined as an ICU length of stay (LOS) of at least 24 hours. Cases were defined as patients with acute DVT during hospitalization, and controls were patients with no documented DVT. Multivariate logistic regression was used to assess the odds of acute DVT in patients with any missed dose of prophylactic antithrombotic medication.

RESULTS

Of 920 patients, 59 (6.4%) experienced an acute, in-hospital DVT. Overall, 64% of patients missed at least 1 dose of VTE prophylaxis medication, and 33% missed more than 3 doses. In the univariate analysis, there was no significant association between any missed dose of prophylaxis medication and acute DVT (odds ratio [OR] = 0.96; CI = 0.56-1.7). Multivariate logistic regression modeling confirmed no association between missed doses of pharmacological VTE medications and acute DVT (OR = 0.69 [0.39-1.2]; P = 0.21). Prolonged hospital LOS was associated with increased odds of acute DVT (LOS = 4-6 days; OR = 0.75 [0.21-2.6]; LOS = 7-13 days; OR = 2.3 [0.9-5.9]; and LOS = ≥14 days; OR = 6.4 [2.6-15.9]).

CONCLUSION

We found no evidence of a relationship between any missed dose of prophylactic antithrombotic medication and development of acute DVT. The odds of acute DVT increased in patients with prolonged hospital LOS.

Evidence-based guidance on venous thromboembolism in patients with solid tumours

Venous thromboembolism (vte) is a serious, life-threatening complication of cancer. Anticoagulation therapy such as low molecular weight heparin (lmwh) has been shown to treat and prevent vte. Cancer therapy is often complex and ongoing, making the management of vte less straightforward in patients with cancer. There are no published Canadian guidelines available to suggest appropriate strategies for the management of vte in patients with solid tumours. We therefore aimed to develop a clear, evidence-based guideline on this topic. A systematic review of clinical trials and meta-analyses published between 2002 and 2013 in PubMed was conducted. Reference lists were hand-searched for additional publications. The National Guidelines Clearinghouse was searched for relevant guidelines. Recommendations were developed based on the best available evidence. In patients with solid tumours, lmwh is recommended for those with established vte and for those without established vte but with a high risk for developing vte. Options for lmwh include dalteparin, enoxaparin, and tinzaparin. No one agent can be recommended over another, but in the setting of renal insufficiency, tinzaparin is preferred. Unfractionated heparin can be used under select circumstances only (that is, when rapid clearance of the anticoagulant is desired). The most common adverse event is bleeding, but major events are rare, and with appropriate follow-up care, bleeding can be monitored and appropriately managed.

Epidemiology of first and recurrent venous thromboembolism: a population-based cohort study in patients without active cancer

Contemporary data from population studies on the incidence and complications of venous thromboembolism (VTE) are limited. An observational cohort study was undertaken to estimate the incidence of first and recurrent VTE. The cohort was identified from all patients in the UK Clinical Practice Research Datalink (CPRD) with additional linked information on hospitalisation and cause of death. Between 2001 and 2011, patients with first VTE were identified and the subset without active cancer-related VTE observed for up to 10 years for recurrent VTE. The 10-year cumulative incidence rates (CIR) were derived with adjustment for mortality as a competing risk event. A total of 35,373 first VTE events (12,073 provoked, 16,708 unprovoked and 6592 active cancer-associated VTE) among 26.9 million person-years of observation were identified. The overall incidence rate (IR) of VTE was 131.5 (95% CI, 130.2-132.9) per 100,000 person-years and 107.0 (95% CI, 105.8-108.2) after excluding cancer-associated VTE. DVT was more common in the young and PE was more common in the elderly. VTE recurrence occurred in 3671 (CIR 25.2%). The IR for recurrence peaked in the first six months at around 11 per 100 person years. It levelled out after three years and then remained at around 2 per 100 person years from year 4-10 of follow-up. The IRs for recurrences were particularly high in young men. In conclusion, VTE is common and associated with high recurrence rates. Effort is required to prevent VTE and to reduce recurrences.

New players in haemostasis and thrombosis

The blood coagulation cascade is essential for haemostasis, but excessive activation can cause thrombosis. Importantly, recent studies have identified factors that contribute to thrombosis but not haemostasis. These include factor XII (FXII), tissue factor-positive microparticles (MPs) and neutrophil extracellular traps (NETs). Studies have shown that FXII plays a role in thrombosis but not haemostasis. FXII is activated in vivo by a variety of negatively-charged polyphosphates, which include extracellular RNA, DNA and inorganic polyphosphate (PolyP) that are released during cell damage and infection. These findings have led to the development of nucleic acid-binding polymers as a new class of anticoagulant drug. Other studies have analysed the role of MPs in experimental thrombosis. MPs are small membrane vesicles released from activated or apoptotic cells. We and others have found that tissue factor-positive MPs enhance thrombosis in mouse models and are elevated in the plasma of pancreatic cancer patients. Finally, NETs have been shown to contribute to experimental venous thrombosis in mouse models and are present in human thrombi. NETs are composed of chromatin fibers that are released from neutrophils undergoing cell death. NETs can capture platelets and increase fibrin deposition. The recent advances in our understanding of the factors contributing to thrombosis in animal models provide new opportunities for the development of safer anticoagulant drugs.

Incidence and cost burden of post-thrombotic syndrome

Post-thrombotic syndrome (PTS) is a long-term complication of deep-vein thrombosis (DVT), manifesting as swelling, pain, edema, venous ectasia, and skin induration of the affected limb. PTS has been estimated to affect 23-60% of individuals with DVT, frequently occurring within 2 years of the DVT episode. Symptomatic DVT, post-operative asymptomatic DVT, and recurrent DVT are all risk factors for the development of PTS. Treatment of PTS is often ineffective and treatment-related costs represent a healthcare burden. Therefore, prevention of DVT is essential to reduce PTS, and thus improve outcomes and reduce overall healthcare costs. Although recommended by guidelines, appropriate DVT prophylaxis remains considerably underused. This review evaluates the incidence, risk factors, and economic impact of PTS. Increasing the awareness of PTS, and the methods to prevent this complication may help reduce its incidence, improve long-term outcomes in patients, and decrease resulting costs associated with treatment.