Venous Thromboembolism Risk in Ischemic Stroke Patients Receiving Extended-Duration Enoxaparin Prophylaxis: Results From the EXCLAIM Study

Effect of extended duration of thromboprophylaxis for medically ill patients

BACKGROUND

There are knowledge gaps regarding the comparative efficacy and safety of various venous thromboprophylaxis regimens with extended timing in patients hospitalized for acute medical illnesses. This study aims to investigate the optimal regimen for the prevention of venous thromboembolism in these patients.

METHODS

We conducted a Bayesian network meta-analysis of randomized controlled trials (RCTs) comparing different venous thromboprophylaxis regimens for acutely ill medical patients. Outcomes included venous thromboembolism, major bleeding, and all-cause mortality. Risk ratios (RR) and associated 95% credible interval (CrI) were estimated. In addition, we assessed the most effective interventions in a subgroup of patients with stroke.

RESULTS

We identified five RCTs involving 40,124 patients. Extended thromboprophylaxis with direct oral anticoagulant (DOAC) (RR 0.78, 95% CrI 0.68 to 0.89) and low molecular weight heparin (LMWH) (RR 0.62, 95% CrI 0.45 to 0.84) were superior to standard therapy in the prevention of venous thromboembolism. However, both of them (DOAC: RR 1.99, 95% CrI 1.38 to 2.92; LMWH: RR 2.56, 95% CrI 1.26 to 5.68) lead to a significant increase in major bleeding). Moreover, both LMWH (RR 0.76, 95% CrI 0.57 to 1.00) and DOAC (RR 0.86, 95% CrI 0.76 to 0.98) with extended thromboprophylaxis showed favorable net clinical benefit compared to standard therapy.

CONCLUSIONS

Extended thromboprophylaxis, especially with LMWH, showed better efficacy in venous thromboembolism reduction with increased risk of major bleeding. The beneficial effect of LMWH with extended timing has also been shown in stroke patients. Overall, extended thromboprophylaxis is associated with a positive net clinical benefit.

Extended venous thromboprophylaxis in patients hospitalized for acute ischemic stroke: A systematic review and meta-analysis

INTRODUCTION

Patients hospitalized for acute ischemic stroke have an increased risk of venous thromboembolism (VTE) that may persist beyond the currently recommended period of 6 to 14 days of thromboprophylaxis. This systematic review evaluated the efficacy and safety of extended venous thromboprophylaxis in patients hospitalized for acute ischemic stroke.

MATERIALS AND METHODS

MEDLINE, EMBASE and Clinicaltrials.gov were searched up to December 2020 for randomized controlled trials comparing extended versus standard venous thromboprophylaxis in patients hospitalized for acute ischemic stroke. The efficacy outcome was a composite of asymptomatic or symptomatic deep vein thrombosis, symptomatic pulmonary embolism, and VTE-related death. The safety outcome was major bleeding. Summary risk ratios (RRs) with corresponding 95% confidence intervals (CIs) were calculated using random-effects models.

RESULTS

Four randomized controlled trials enrolling 33718 patients were included. Of 4330 (12.8%) patients hospitalized for acute ischemic stroke, 2152 (49.7%) received extended thromboprophylaxis for four to five weeks with betrixaban (n = 405, 18.8%), enoxaparin (n = 198, 9.2%), or rivaroxaban (n = 1549, 72.0%), and 2178 (50.3%) received standard venous thromboprophylaxis with enoxaparin. VTE risk was lower in acute ischemic stroke patients receiving extended thromboprophylaxis (RR 0.67; 95% CI, 0.43 to 1.04; 13 fewer per 1000), whereas the increase in major bleeding seemed trivial when compared with standard prophylaxis (RR 1.10; 95% CI, 0.31 to 3.95; 1 more per 1000).

CONCLUSION

In patients hospitalized for acute ischemic stroke, the net clinical benefit may favor extended venous thromboprophylaxis for four to five weeks over standard thromboprophylaxis.

Exploring real-world evidence to uncover unknown drug benefits and support the discovery of new treatment targets for depressive and bipolar disorders

BACKGROUND

Major depressive and bipolar disorders are associated with impaired quality of life and high economic burden. Although progress has been made in our understanding of the underlying pathophysiology and the development of novel pharmacological treatments, a large unmet need remains for finding effective treatment options. The purpose of this study was to identify potential new mechanisms of actions or treatment targets that could inform future research and development opportunities for major depressive and bipolar disorders.

METHODS

A self-controlled cohort study was conducted to examine associations between 1933 medications and incidence of major depressive and bipolar disorders across four US insurance claims databases. Presence of incident depressive or bipolar disorders were captured for each patient prior to or after drug exposure and incident rate ratios were calculated. Medications that demonstrated ≥50% reduction in risk for both depressive and bipolar disorders within two or more databases were evaluated as potential treatment targets.

RESULTS

Eight medications met our inclusion criteria, which fell into three treatment groups: drugs used in substance use disorders; drugs that affect the cholinergic system; and drugs used for the management of cardiovascular-related conditions.

LIMITATIONS

This study was not designed to confirm a causal association nor inform current clinical practice. Instead, this research and the methods employed intended to be hypothesis generating and help uncover potential treatment pathways that could warrant further investigation.

CONCLUSIONS

Several potential drug targets that could aid further research and discovery into novel treatments for depressive and bipolar disorders were identified.

Short-Term and Long-Term Safety and Efficacy of Treatment of Acute Ischemic Stroke with Low-Molecular-Weight Heparin: Meta-Analysis of 19 Randomized Controlled Trials

OBJECTIVE

Currently, it remains controversial about guidelines for the application of low-molecular-weight heparin (LMWH) in patients with acute ischemic stroke (AIS). Therefore this meta-analysis was carried out, aiming to systematically investigate the short-term and long-term safety and efficacy of LMWH in AIS patients.

METHODS

Three electronic databases-PubMed, Embase database, and Cochrane library-were comprehensively retrieved by 2 investigators independently. Finally, a total of 19 randomized controlled trials were enrolled for analysis. The safety endpoints in this study included all-cause mortality and the risk of bleeding (major, minor, or cerebral hemorrhage). The efficacy endpoints were the prevention of deep vein thrombosis (DVT) and recurrent stroke.

RESULTS

The application of LMWH led to a decreased risk of DVT, and there was no significant association in all-cause mortality or recurrent stroke. According to age-stratified analyses, the risk of all-cause mortality increased by 39% (risk ratio 1.39, 1.03-1.88; I² 0%) in AIS patients aged older than 70 years who used LMWH for 14 days, and there was no significant effect on preventing DVT (risk ratio 0.69, 0.14-3.52; I² 26.4%) in patients aged younger than 70 years old within 3 months. Moreover, enoxaparin and danaparoid were more effective at preventing DVT, regardless of age.

CONCLUSIONS

To sum up, on the basis of limited studies available currently, the early use of LMWH in AIS patients aged older than 70 years should be cautious because it may increase the risk of all-cause mortality. For patients younger than 70 years old, the early use of LMWH significantly reduces the short-term risk of DVT, but there is no significant relationship in the long term. In terms of DVT prevention, enoxaparin and danaparoid are probably more effective. Nonetheless, more future randomized controlled trials are warranted to verify and support this conclusion.

The Role of Stroke as a Trigger for Incident Venous Thromboembolism: Results from a Population-based Case-Crossover Study

Stroke is associated with a short-term increased risk of subsequent venous thromboembolism (VTE). It is unclear to what extent this association is mediated by stroke-related complications that are potential triggers for VTE, such as immobilization and infection. We aimed to investigate the role of acute stroke as a trigger for incident VTE while taking other concomitant VTE triggers into account. We conducted a population-based case-crossover study with 707 VTE patients. Triggers were registered during the 90 days before a VTE event (hazard period) and in four preceding 90-day control periods. Conditional logistic regression was used to estimate odds ratios with 95% confidence intervals (CIs) for VTE according to triggers. Stroke was registered in 30 of the 707 (4.2%) hazard periods and in 6 of the 2,828 (0.2%) control periods, resulting in a high risk of VTE, with odds ratios of 20.0 (95% CI: 8.3–48.1). After adjustments for immobilization and infection, odds ratios for VTE conferred by stroke were attenuated to 6.0 (95% CI: 1.6–22.1), and further to 4.0 (95% CI: 1.1–14.2) when other triggers (major surgery, red blood cell transfusion, trauma, and central venous catheter) were added to the regression model. A mediation analysis revealed that 67.8% of the total effect of stroke on VTE risk could be mediated through immobilization and infection. Analyses restricted to ischemic stroke yielded similar results. In conclusion, acute stroke was a trigger for VTE, and the association between stroke and VTE risk appeared to be largely mediated by immobilization and infection.

Reporting of sex and gender in randomized controlled trials in Canada: a cross-sectional methods study

BACKGROUND

Accurate reporting on sex and gender in health research is integral to ensuring that health interventions are safe and effective. In Canada and internationally, governments, research organizations, journal editors, and health agencies have called for more inclusive research, provision of sex-disaggregated data, and the integration of sex and gender analysis throughout the research process. Sex and gender analysis is generally defined as an approach for considering how and why different subpopulations (e.g., of diverse genders, ages, and social locations) may experience health conditions and interventions in different or similar ways.The objective of this study was to assess the extent and nature of reporting about sex and/or gender, including whether sex and gender analysis (SGA) was carried out in a sample of Canadian randomized controlled trials (RCTs) with human participants.

METHODS

We searched MEDLINE from 01 January 2013 to 23 July 2014 using a validated filter for identification of RCTs, combined with terms related to Canada. Two reviewers screened the search results to identify the first 100 RCTs that were either identified in the trial publication as funded by a Canadian organization or which had a first or last author based in Canada. Data were independently extracted by two people from 10% of the RCTs during an initial training period; once agreement was reached on this sample, the remainder of the data extraction was completed by one person and verified by a second.

RESULTS

The search yielded 1433 records. We screened 256 records to identify 100 RCTs which met our eligibility criteria. The median sample size of the RCTs was 107 participants (range 12-6085). While 98% of studies described the demographic composition of their participants by sex, only 6% conducted a subgroup analysis across sex and 4% reported sex-disaggregated data. No article defined "sex" and/or "gender." No publication carried out a comprehensive sex and gender analysis.

CONCLUSIONS

Findings highlight poor uptake of sex and gender considerations in the Canadian RCT context and underscore the need for better articulated guidance on sex and gender analysis to improve reporting of evidence, inform policy development, and guide future research.

Variation in Definitions of Immobility in Pharmacological Thromboprophylaxis Clinical Trials in Medical Inpatients: A Systematic Review

BACKGROUND

Although immobility is a common risk factor for venous thromboembolism (VTE) in medical inpatients, lack of a consistent definition of this term may limit accurate assessment of VTE risk for thromboprophylaxis.

OBJECTIVE

To examine various definitions of immobility used in recent pharmacological thromboprophylaxis clinical trials.

DATA SOURCES

PubMed and relevant references from articles/reviews from 2008 to 2016 were searched. Randomized controlled trials (RCTs) and other clinical studies involving adult hospitalized medical patients in acute care hospital settings that used the term immobility were selected. Two investigators independently abstracted data in duplicate, and accuracy was checked by a third investigator.

RESULTS

Twenty-one clinical studies were included. There was heterogeneity among individual VTE risk factors, with respect to the definition of immobility in medical inpatients in these trials. Thirteen studies utilized objective criteria to define "immobility" including duration (12 studies) and distance or time walked (6 studies). In contrast, 7 studies focused principally on subjective definitions (ie, describing the nature of immobility rather than specifying its quantitative measurement). Three RCTs vaguely defined the level of patient's immobility after hospitalization.

CONCLUSION

Despite the well-known effectiveness of pharmacological thromboprophylaxis for the prevention of VTE in acutely ill medical patients, there is no current consensus on how to define immobility. The heterogeneous nature of definitions of immobility has led to uncertainty about the importance of immobility in VTE risk assessment models. Although clinical studies have incorporated varying definitions of immobility into their inclusion criteria, immobility as a specific VTE risk factor has not been clearly defined.

Safety of early pharmacological thromboprophylaxis after subarachnoid hemorrhage

OBJECTIVE

The recent guidelines on management of aneurysmal subarachnoid hemorrhage (aSAH) advise pharmacological thromboprophylaxis (PTP) after aneurysm obliteration. However, no study has addressed the safety of PTP in the aSAH population. Therefore, the aim of this study was to assess the safety of early PTP after aSAH.

METHODS

Retrospective cohort of aSAH patients admitted between January 2012 and June 2013 in a single high-volume aSAH center. Traumatic SAH and perimesencephalic hemorrhage patients were excluded. Patients were grouped according to PTP timing: early PTP group (PTP within 24 hours of aneurysm treatment), and delayed PTP group (PTP started > 24 hours).

RESULTS

A total of 174 SAH patients (mean age 56.3±12.5 years) were admitted during the study period. Thirty-nine patients (22%) did not receive PTP, whereas 135 patients (78%) received PTP after aneurysm treatment or negative angiography. Among the patients who received PTP, 65 (48%) had an external ventricular drain. Twenty-eight patients (21%) received early PTP, and 107 (79%) received delayed PTP. No patient in the early treatment group and three patients in the delayed PTP group developed an intracerebral hemorrhagic complication. Two required neurosurgical intervention and one died. These three patients were on concomitant PTP and dual antiplatelet therapy.

CONCLUSIONS

The initiation of PTP within 24 hours may be safe after the treatment of a ruptured aneurysm or in angiogram-negative SAH patients with diffuse aneurysmal hemorrhage pattern. We suggest caution with concomitant use of PTP and dual antiplatelet agents, because it possibly increases the risk for intracerebral hemorrhage.

Venous thromboembolism: identifying patients at risk and establishing prophylaxis

Venous thromboembolism (VTE) is a major cause of morbidity and mortality and is associated with substantial healthcare costs. Identification of patients at risk of developing VTE enables appropriate thromboprophylaxis to be implemented. Although no predisposing risk factors can be identified in many patients in whom VTE develops, most have at least one underlying risk factor which can be categorized according to whether it confers low, moderate, or high risk. Clinical trials have demonstrated the effectiveness of thromboprophylaxis, both non-pharmacological and pharmacological, in a host of medical settings and there is sufficient evidence to support routine prophylaxis in many groups of patients. The implementation of decision making tools based on risk factor assessment improves the prescription of appropriate VTE prophylaxis. Nonetheless, thromboprophylaxis is often inadequate, with haphazard risk assessment and application of guidelines, leading to easily preventable instances of VTE. The most commonly used agents for pharmacological thromboprophylaxis of VTE are low dose unfractionated heparin; a low molecular weight heparin such as dalteparin, enoxaparin or tinzaparin; fondaparinux; warfarin; or aspirin. However, these have a number of drawbacks, principally the need for parenteral administration (with heparins) and frequent coagulation monitoring (with warfarin). The optimal anticoagulant would be orally administered, with a wide therapeutic window, rapid onset of action, predictable pharmacodynamics and pharmacokinetics, minimal interactions with food and other drugs, an ability to inhibit free and clot-bound coagulation factors, low, non-specific binding, and no requirement for routine coagulation monitoring or dose adjustment. A number of novel, single-target oral anticoagulants have been developed that appear to fulfill many of these requirements. This narrative review discusses the use of guidelines and risk assessment tools to identify patients at risk of VTE; it provides an overview of appropriate prophylaxis strategies in these patients with a summary of clinical trial results with novel oral anticoagulants.

Extended-Duration Venous Thromboembolism Prophylaxis in Hospitalized Acutely Ill Medical Patients

Objective: To evaluate the risks and benefits of extended-duration thromboprophylaxis (EDT) beyond hospitalization in acutely ill medical patients. Data Sources: PubMed was searched from inception (1946) through February 2015 for the search terms venous thrombosis/prevention and control, venous thromboembolism/prevention and control, anticoagulants, and aspirin. Study Selection and Data Extraction: Relevant clinical trials evaluating pharmacologic strategies for EDT were screened for inclusion. Bibliographies of articles were extensively reviewed for additional sources. Data Synthesis: Three studies, and one additional subgroup analysis, were identified for inclusion. Enoxaparin and rivaroxaban demonstrated a significant reduction in venous thromboembolism (VTE) with EDT, but the benefit with enoxaparin was limited to the highest risk groups and women. The improved efficacy in both studies was accompanied by a ~2.5-fold increase in risk of major hemorrhage. Apixaban was unable to demonstrate a reduction of VTE and was also associated with a significant increase in bleeding. Conclusions: EDT should not be routinely provided to all medically ill patients. It may be considered in patients at the highest risk for VTE, but careful consideration must be used due to the increased risk of bleeding.

Venous thromboembolism prophylactic methods in acute stroke patients - current state of knowledge

Deep venous thrombosis (DVT) and its sequel, pulmo-nary em-bolism (PE), are serious complications of stroke. There are pharmacological and physical methods to prevent these complications. The authors review the lite-rature and present the current state of knowledge re-garding the effectiveness of each of the DVT and PE prevention methods in stroke patients and cite current Polish, European and American recommendations re-garding this issue. Heparins are the method of choice for the prevention of venous thromboembolism in both ischaemic and haemorrhagic stroke patients.

Prevention of venous thromboembolism in acutely ill medical patients after the results of recent trials with the new oral anticoagulants

Venous thromboembolism (VTE) is a common potentially life-threatening complication in acutely ill medical patients; over 70 % of the fatal episodes of pulmonary embolism during hospitalization occur in non-surgical patients. In the absence of thromboprophylaxis, the incidence of venographically detected deep vein thrombosis is about 15 % in medical patients. Several trials and meta-analyses have clearly demonstrated the prophylactic role of unfractionated heparin, low molecular weight heparin and fondaparinux. Although over the past few years the knowledge of epidemiology, clinical features and prophylaxis in medical patients has significantly improved, there remain a number of controversial areas that require further investigation. Newer VTE risk assessment models have been proposed to select high risk hospitalized medical patients, but they still require external validation; scarce data are available to stratify patients to identify their individual bleeding risk. The optimal duration of thromboprophylaxis in medical patients is still a matter of debate; currently, extended prophylaxis after discharge is not recommended, but it may be required for subgroup of patients with persistently high VTE risk and a negligible risk of bleeding. Based on the results of recent studies, the new oral anticoagulants appear to have a very limited role, if any. However, a better risk stratification of patients who have a persistently increased risk of VTE is warranted to improve the risk to benefit profile of any anticoagulant drug to be used in this setting.

Incidence of venous thromboembolism in the wake of the Clots in Legs Or sTockings after Stroke (CLOTS) study

BACKGROUND AND PURPOSE

In the United Kingdom, compressive stockings were standard care in all stroke units until the publication of the Clots in Legs Or sTockings after Stroke (CLOTS) trial results in May 2009, which concluded that stockings were ineffective. The aim of this audit was to assess whether this change in practice was associated with any change in venous thromboembolism incidence in routine clinical practice.

METHOD

All stroke register entries at the University Hospital of North Staffordshire from 2 years before the publication of the CLOTS trial results to 2 years after were identified and included in this audit. The hospital radiology reporting system was then cross-checked for evidence of venous thromboembolism on computed tomography pulmonary angiogram, ventilation/perfusion lung scan, and leg Doppler reports.

RESULTS

There were 773 patients in the before cohort and 861 in the after cohort (mean age, 74/74 years; men, 47%/45%; and ischemic stroke, 87%/85%, respectively). Symptomatic venous thromboembolism incidence was the same in both cohorts, 21 (2.7%) in the before cohort and 26 (3.0%) in the after cohort (P=0.8). There was a trend toward more deep vein thrombosis (9 [1.2%] versus 19 [2.2%]; P=0.1) and fewer pulmonary embolisms (12 [1.6%] versus 6 [0.7%]; P=0.2) in the after cohort.

CONCLUSIONS

Discontinuation of compressive stockings did not increase venous thromboembolism incidence. There was a trend toward more deep vein thrombosis and fewer PEs after CLOTS, which might be because of increased clinical vigilance in the diagnosis of deep vein thrombosis, but a chance variation cannot be excluded.

Do novel oral anticoagulants do better than standard therapy in the treatment of deep vein thrombosis?

The focus of DVT treatment is the prevention of recurrence and thrombus migration by treatment with anticoagulants. The aim is to improve outcomes by reducing clot burden and by preventing thrombus propagation, in order to prevent PE and the development of long-term complication. Actually, initial therapy is parenteral anticoagulation, mainly with low molecular weight heparin followed by a vitamin K antagonist (VKA) for triggered and idiopathic DVT. The long term treatment suggestion with a VKA is for sure the most challenging therapeutic scenario, showing all the disadvantages of VKA especially in the onset phase when therapeutic levels of VKA are difficult to achieve. The difference between VKAs and NOACs is the fact, that NOACs target a specific factor in the coagulation cascade. At time now two pathways have been chosen for treatment options, the direct inhibition of active sites of thrombin and factor Xa. Routine monitoring is not required and the drugs can be administered in fixed doses, which should increase patient adherence to long term treatment. At time now, four novel anticoagulants are called to be options for DVT treatment. Rivaroxaban, apixaban and edoxaban are direct FXa inhibitors, whereas dabigtran etexilate is a direct thrombin inhibitor.

Rate of deep-vein thrombosis and pulmonary embolism during the care continuum in patients with acute ischemic stroke in the United States

BACKGROUND

Deep-vein thrombosis (DVT) and pulmonary embolism (PE) are frequent and life-threatening complications of ischemic stroke. We evaluated rates of symptomatic DVT/PE, and of in-hospital and post-discharge thromboprophylaxis in patients with acute ischemic stroke (AIS).

METHODS

In a retrospective US database analysis, data were extracted from the Premier Perspective™-i3 Pharma Informatics linked database for patients aged ≥18 years who were hospitalized for ischemic stroke from January 2005 to November 2007, and who had ≥6 months' continuous plan enrollment prior to index hospitalization. Patients discharged to an acute-care facility or with atrial fibrillation were excluded. Prophylaxis was evaluated during index hospitalization and for 14 days' post-discharge. DVT/PE rates were calculated during index hospitalization and up to 30 days post-discharge.

RESULTS

A total of 1524 patients were included; 46.1% received pharmacological and/or mechanical prophylaxis in-hospital (28.3%, 11.4% and 12.3% received unfractionated heparin, enoxaparin and mechanical prophylaxis, respectively). 6.4% of patients received outpatient pharmacological prophylaxis; warfarin was most frequently prescribed (5.9%). Total mean ± standard deviation length of index hospitalization was 3.0 ± 2.5 days. Mean prophylaxis duration in all patients was 0.9 ± 1.5 days in-hospital and 1.7 ± 6.9 days post-discharge. Symptomatic DVT/PE occurred in 25 patients overall (1.64%), with an inpatient rate of 0.98% and an outpatient rate of 0.66%.

CONCLUSIONS

Approximately 1% of patients with AIS experienced symptomatic in-hospital and/or post-discharge DVT/PE. Although 46% received prophylaxis in-hospital, only 6% received prophylaxis in the outpatient setting. This highlights the need for sustained thromboprophylaxis prescribing across the continuum of care.