Preventing hospital associated venous thromboembolism

Evaluation of venous thromboembolism risk assessment models for hospital inpatients: the VTEAM evidence synthesis

Background

Pharmacological prophylaxis during hospital admission can reduce the risk of acquired blood clots (venous thromboembolism) but may cause complications, such as bleeding. Using a risk assessment model to predict the risk of blood clots could facilitate selection of patients for prophylaxis and optimise the balance of benefits, risks and costs.

Objectives

We aimed to identify validated risk assessment models and estimate their prognostic accuracy, evaluate the cost-effectiveness of different strategies for selecting hospitalised patients for prophylaxis, assess the feasibility of using efficient research methods and estimate key parameters for future research.

Design

We undertook a systematic review, decision-analytic modelling and observational cohort study conducted in accordance with Enhancing the QUAlity and Transparency Of health Research (EQUATOR) guidelines.

Setting

NHS hospitals, with primary data collection at four sites.

Participants

Medical and surgical hospital inpatients, excluding paediatric, critical care and pregnancy-related admissions.

Interventions

Prophylaxis for all patients, none and according to selected risk assessment models.

Main outcome measures

Model accuracy for predicting blood clots, lifetime costs and quality-adjusted life-years associated with alternative strategies, accuracy of efficient methods for identifying key outcomes and proportion of inpatients recommended prophylaxis using different models.

Results

We identified 24 validated risk assessment models, but low-quality heterogeneous data suggested weak accuracy for prediction of blood clots and generally high risk of bias in all studies. Decision-analytic modelling showed that pharmacological prophylaxis for all eligible is generally more cost-effective than model-based strategies for both medical and surgical inpatients, when valuing a quality-adjusted life-year at £20,000. The findings were more sensitive to uncertainties in the surgical population; strategies using risk assessment models were more cost-effective if the model was assumed to have a very high sensitivity, or the long-term risks of post-thrombotic complications were lower. Efficient methods using routine data did not accurately identify blood clots or bleeding events and several pre-specified feasibility criteria were not met. Theoretical prophylaxis rates across an inpatient cohort based on existing risk assessment models ranged from 13% to 91%.

Limitations

Existing studies may underestimate the accuracy of risk assessment models, leading to underestimation of their cost-effectiveness. The cost-effectiveness findings do not apply to patients with an increased risk of bleeding. Mechanical thromboprophylaxis options were excluded from the modelling. Primary data collection was predominately retrospective, risking case ascertainment bias.

Conclusions

Thromboprophylaxis for all patients appears to be generally more cost-effective than using a risk assessment model, in hospitalised patients at low risk of bleeding. To be cost-effective, any risk assessment model would need to be highly sensitive. Current evidence on risk assessment models is at high risk of bias and our findings should be interpreted in this context. We were unable to demonstrate the feasibility of using efficient methods to accurately detect relevant outcomes for future research.

Future work

Further research should evaluate routine prophylaxis strategies for all eligible hospitalised patients. Models that could accurately identify individuals at very low risk of blood clots (who could discontinue prophylaxis) warrant further evaluation.

Study registration

This study is registered as PROSPERO CRD42020165778 and Researchregistry5216.

Funding

This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme (NIHR award ref: NIHR127454) and will be published in full in Health Technology Assessment; Vol. 28, No. 20. See the NIHR Funding and Awards website for further award information.

Effectiveness and cost effectiveness of pharmacological thromboprophylaxis for medical inpatients: decision analysis modelling study

Objective

To determine the balance of costs, risks, and benefits for different thromboprophylaxis strategies for medical patients during hospital admission.

Design

Decision analysis modelling study.

Setting

NHS hospitals in England.

Population

Eligible adult medical inpatients, excluding patients in critical care and pregnant women.

Interventions

Pharmacological thromboprophylaxis (low molecular weight heparin) for all medical inpatients, thromboprophylaxis for none, and thromboprophylaxis given to higher risk inpatients according to risk assessment models (Padua, Caprini, IMPROVE, Intermountain, Kucher, Geneva, and Rothberg) previously validated in medical cohorts.

Main outcome measures

Lifetime costs and quality adjusted life years (QALYs). Costs were assessed from the perspective of the NHS and Personal Social Services in England. Other outcomes assessed were incidence and treatment of venous thromboembolism, major bleeds including intracranial haemorrhage, chronic thromboembolic complications, and overall survival.

Results

Offering thromboprophylaxis to all medical inpatients had a high probability (>99%) of being the most cost effective strategy (at a threshold of £20 000 (€23 440; $25 270) per QALY) in the probabilistic sensitivity analysis, when applying performance data from the Padua risk assessment model, which was typical of that observed across several risk assessment models in a medical inpatient cohort. Thromboprophylaxis for all medical inpatients was estimated to result in 0.0552 additional QALYs (95% credible interval 0.0209 to 0.1111) while generating cost savings of £28.44 (-£47 to £105) compared with thromboprophylaxis for none. No other risk assessment model was more cost effective than thromboprophylaxis for all medical inpatients when assessed in deterministic analysis. Risk based thromboprophylaxis was found to have a high (76.6%) probability of being the most cost effective strategy only when assuming a risk assessment model with very high sensitivity is available (sensitivity 99.9% and specificity 23.7% v base case sensitivity 49.3% and specificity 73.0%).

Conclusions

Offering pharmacological thromboprophylaxis to all eligible medical inpatients appears to be the most cost effective strategy. To be cost effective, any risk assessment model would need to have a very high sensitivity resulting in widespread thromboprophylaxis in all patients except those at the very lowest risk, who could potentially avoid prophylactic anticoagulation during their hospital stay.

Venous Thromboembolism Prophylaxis in Medical and Surgical Patients - What's Our Reality?

INTRODUCTION

Venous thromboembolism (VTE) includes pulmonary embolism (PE), deep vein thrombosis (DVT) in lower limbs, and thrombosis in rare locations. VTE is a common cardiovascular disease, being the leading preventable cause of in-hospital death. Both surgical and acute medical patients have an elevated risk of developing VTE. VTE risk assessment is essential to identify patients who might benefit from VTE prophylaxis accurately. Clinical data on risk factors and prophylaxis in Portugal are scarce. We aimed to determine the proportion of at-risk patients who received prophylaxis and the incidence of bleeding events. We also intended to study the rate of VTE in a cohort of medical and surgical patients during the hospitalization period and three months after discharge.

METHODS

During one week in 2020, adults admitted for more than 72hr to a medical or surgical ward were included. The study excluded patients with a diagnosis of VTE three months before hospitalization and who were either chronically receiving anticoagulation therapy or had started it 48 hours after admission. Risk assessments were based on the Padua Prediction Score (PPS) for medical patients and the Caprini Risk Assessment Model (CRAM) for surgical patients. We used CHEST guidelines, 9th edition, to determine the adequacy of the prophylactic method.

RESULTS

A total of 123 patients were analyzed, 18.7% of which tested positive for SARS-CoV-2. VTE risk in surgical patients was categorized as very low or low (16.6%), moderate (37.5%), and high (43.8%), according to the CRAM. Risk in medical patients was categorized as low (60.0%) or high (40.0%) according to the PPS. We estimated that VTE chemoprophylaxis was overused in about 30.0% of patients vs. 7.0% who were at risk and did not receive appropriate chemoprophylaxis. The rate of thromboembolic events was 4.1% (n=5), 2 of which happened after discharge. Two of these patients were under VTE prophylaxis during hospitalization. Major bleeding occurred in 2.4% of patients (n=3).

DISCUSSION

A significant number of hospitalized patients are deemed to be at risk for VTE, making appropriate prophylaxis essential. The results emphasize the insufficient management of VTE prophylaxis.

HIDDEN2: Study protocol for the hospital deep vein thrombosis detection study in patients with cancer receiving palliative care

INTRODUCTION

Medical patients, admitted acutely to hospital, are at risk of venous thromboembolism (VTE). Clinical guidelines advise thromboprophylaxis prophylaxis for those at high risk of VTE. VTE is a common sequela of cancer, but guidelines take little consideration of cancer as an independent risk factor and their utility in palliative care patients is unclear. The hospice inpatient deep vein thrombosis (DVT) detection study (HIDDen) reported a 28% prevalence of asymptomatic iliofemoral DVT in hospice patients of poor performance status (PS) and prognosis, calling into question the utility of thromboprophylaxis in the palliative care setting. However, the majority of cancer inpatients receiving palliative care are admitted to hospital through the acute medical setting, yet their risk factors for VTE may differ from those admitted to hospices.

OBJECTIVE

To better understand the prevalence and behaviours of VTE in patients with cancer receiving palliative care who are admitted as an acute medical emergency.

DESIGN

Multicentre, observational cohort study.

SETTING

Secondary care acute hospitals in South Wales, UK.

PATIENTS

We plan to recruit 232 patients≥18 years old with a diagnosis of incurable cancer, and/or receiving palliative or best supportive care who are admitted acutely to hospital. Patients will be followed up for a maximum of 6 months following registration.

PRIMARY OUTCOME

Presence of lower extremity DVT.

SECONDARY OUTCOMES

Symptom burden attributed to DVT or pulmonary embolism, patient PS, patient demographics and development of new VTE within 90 days of registration.

ANALYSIS

The study statistical analysis plan will document analysis, methodology and procedures.

ETHICS AND DISSEMINATION

Ethical approval was obtained from the Wales Research Ethics Committee, reference 22/WA/0037 (IRAS 306352)-the main trial results will be analysed as soon as practically possible and the publication shared with investigators and on sponsor website; applications to access trial data will be subject to sponsor review process.

How I approach the prevention and treatment of thrombotic complications in hospitalized patients

This article uses case-based discussion to review prevention and management of thrombotic problems in hospitalized patients that involve a clinical hematologist. There is variation in the clinical hematologist's role in thrombosis practice throughout the world, and we discuss this where indicated. Hospital-associated venous thromboembolism (VTE), or hospital-associated thrombosis (HAT), is the term to cover VTE occurring during admission and for 90 days postdischarge and is a common patient safety problem. HATs are the most common cause of VTE accounting for 55% to 60% of all VTE, with an estimated 10 million occurring globally. VTE risk assessment alongside evidence-based thromboprophylaxis reduces this risk significantly. Many hospitalized patients, especially older patients, use direct oral anticoagulants (DOACs), mainly to prevent stroke in atrial fibrillation. DOACs require perioperative management and may need urgent reversal. Other complex interventions such as extracorporeal membrane oxygenation which require anticoagulation are also discussed. Lastly, those with uncommon high-risk thrombophilias, especially those with antithrombin deficiency, produce unique challenges when hospitalized.

Impact of thromboprophylaxis on hospital acquired thrombosis following discharge in patients admitted with COVID-19: Multicentre observational study in the UK

Post-discharge thromboprophylaxis in patients admitted with COVID-19 remains controversial. We aimed to determine the impact of thromboprophylaxis on hospital acquired thrombosis (HAT) in patients (≥18 years) discharged following admission for COVID-19 in an observational study across 26 NHS Trusts in the UK (01.04.2020-31.12.2021). Overall, 8895 patients were included to the study: 971 patients were discharged with thromboprophylaxis and propensity score matched (PSM) with a desired ratio of 1:1, from patients discharged without thromboprophylaxis. Patients with heparin induced thrombocytopenia, major bleeding during admission and pregnant women were excluded. As expected from 1:1 PSM, no difference was observed in parameters between the two groups, including duration of hospital stay, except the thromboprophylaxis group had a significantly higher proportion who had received therapeutic dose anticoagulation during admission. There were no differences in the laboratory parameters especially D-dimers between the two groups at admission or discharge. Median duration of thromboprophylaxis following discharge from hospital was 4 weeks (1-8 weeks). No difference was found in HAT in patients discharged with TP versus no TP (1.3% vs. 0.92%, p = 0.52). Increasing age and smoking significantly increased the risk of HAT. Many patients in both cohorts had raised D-dimer at discharge but D-dimer was not associated with increased risk of HAT.

Formal and informal venous thromboembolism risk assessment and impact on prescribing of thromboprophylaxis: a retrospective cohort study

BACKGROUND

Hospital-acquired thrombosis (HAT) is a leading cause of preventable death and disability worldwide. HAT includes any venous thromboembolic (VTE) event occurring in-hospital or within 90-days of hospitalisation. Despite availability of evidence-based guidelines for HAT risk assessment and prophylaxis, guidelines are still underutilised.

AIM

To determine the proportion of patients who developed HAT that could have been potentially prevented with appropriate VTE risk assessment and prophylaxis at a large public hospital in New Zealand. Additionally, the predictors of VTE risk assessment and thromboprophylaxis were examined.

METHOD

VTE patients admitted under general medicine, reablement, general surgery, or orthopaedic surgery service were identified using ICD-10-AM codes. Data were collected on patient characteristics, VTE risk factors, and the thromboprophylaxis regimen prescribed. The hospital VTE guidelines were used to determine rates of VTE risk assessment and the appropriateness of thromboprophylaxis.

RESULTS

Of 1302 VTE patients, 213 HATs were identified. Of these, 116 (54%) received VTE risk assessment, and 98 (46%) received thromboprophylaxis. Patients who received VTE risk assessment were 15 times more likely to receive thromboprophylaxis (odds ratio [OR] = 15.4; 95% CI 7.65-30.98) and 2.8 times more likely to receive appropriate thromboprophylaxis (OR = 2.79; 95% CI 1.59-4.89).

CONCLUSION

A large proportion of high-risk patients who were admitted to medical, general surgery and reablement services and who developed HAT did not receive VTE risk assessment and thromboprophylaxis during their index admission, demonstrating a significant gap between guideline recommendations and clinical practice. Implementing mandatory VTE risk assessment and adherence to guidelines to improve thromboprophylaxis prescription in hospitalised patients may help reduce the burden of HAT.

A bidirectional Mendelian randomized study of classical blood lipids and venous thrombosis

There is still some controversy about the relationship between lipids and venous thrombosis (VTE). A bidirectional Mendelian randomization (MR) study was conducted to clarify the causal relationship between three classical lipids (low-density lipoprotein (LDL), high-density lipoprotein (HDL) and triglycerides (TGs)) and venous thromboembolism (VTE) (deep venous thrombosis (DVT) and pulmonary embolism (PE)). Three classical lipids and VTE were analysed by bidirectional Mendelian randomization (MR). We used the random effect inverse variance weighted (IVW) model as the main analysis model and the weighted median method, simple mode method, weighted mode method and MR-Egger methods as supplementary methods. The leave-one-out test was used to determine the influence of outliers. The heterogeneity was calculated by using Cochran Q statistics in the MR-Egger and IVW methods. The intercept term in the MR‒Egger regression was used to indicate whether horizontal pleiotropy affected the results of the MR analysis. In addition, MR-PRESSO identified outlier single-nucleotide polymorphisms (SNPs) and obtained a stable result by removing outlier SNPs and then performing MR analysis. When we used three classical lipids (LDL, HDL and TGs) as exposure variables, no causal relationship between them and VTE (DVT and PE) was found. In addition, we did not find significant causal effects of VTE on the three classical lipids in reverse MR analysis. There is no significant causal relationship between three classical lipids (LDL, HDL and TGs) and VTE (DVT and PE) from a genetic point of view.

Improving the rate of inferior vena cava filter retrieval through multidisciplinary engagement

Background

The placement of retrievable inferior vena cava (IVC) filters occurs commonly, but retrieval rates remain low. Consequently, there is an unmet clinical need to ensure appropriate follow-up and retrieval of these devices.

Objectives

To determine the association between an IVC filter surveillance team with filter retrievals or a documented filter plan, time to retrieval, and incidence of filter complications or recurrent venous thromboembolism.

Methods

Ambidirectional cohort study evaluating consecutive IVC filter insertions before and after the implementation of a multidisciplinary surveillance team (MDST). We report an odds ratio (OR) with 95% CIs, adjusted by age, sex, weight, and malignancy status.

Results

Overall, 453 patients were included, with 272 individuals in the pre-MDST cohort and 181 individuals in the post-MDST cohort. The MDST was associated with a higher composite primary outcome of IVC filter retrieval or a documented filter plan from 79.4% in the pre-MDST cohort to 96.1% in the post-MDST cohort (OR, 6.44; 95% CI, 3.06-15.84). Compared with the pre-MDST cohort, IVC filter retrieval rates were higher in the post-MDST cohort (52.6%-73.5%, respectively; (OR, 2.50; 95% CI, 1.67-3.78). The MDST was associated with a shorter median time-to-filter retrieval (187-150 days, hazard ratio, 1.78; 95% CI, 1.39-2.29), but there was no significant difference when comparing symptomatic or clinically significant IVC filter complications, recurrent venous thromboembolism, or mortality.

Conclusion

Our study demonstrates the importance of a structured program to ensure timely IVC filter retrieval and ultimately improve patient care.

Predicting venous thromboembolism in non-surgical hospitalized patients with type 2 diabetes mellitus: development and validation of a nomogram

BACKGROUND

Due to confounders like hyperglycemia, patients with type 2 diabetes mellitus (T2DM) have an increased susceptibility to venous thromboembolism (VTE). However, formal risk assessment models, such as using the Padua score, do not include all T2DM-associated risk factors for VTE. Therefore, this study aims to develop and validate a predictive nomogram for VTE in non-surgical inpatients with T2DM.

METHODS

We retrospectively analyzed the clinical and biochemical data of 420 non-surgical inpatients with T2DM between 2017 and 2021 from three centers (the PLA 474^th hospital, the Second Affiliated Hospital of Xinjiang Medical University and the Fifth Affiliated Hospital of Xinjiang Medical University). A multivariate analysis based on logistic regression model was performed to identify independent risk factors and construct a nomogram. The predictive values were compared by calculating the integrated discrimination improvement (IDI) and net reclassification improvement (NRI), and by decision curve analysis (DCA).

RESULTS

Old age, BMI, D-dimer, hypoproteinemia, acute infection, acute myocardial infarction, cerebral ischemic stroke, reduced mobility, and heart/respiratory failure were independent risk factors for VTE in non-surgical inpatients with T2DM, as indicated by the multivariate analysis. The nomogram demonstrated superior discriminative ability compared to the Padua score (area under the curve: 0.923 vs. 0.849). NRI and IDI were also observed, and the DCA identified the greater net benefit and clinical utilization of the new nomogram.

CONCLUSIONS

A predictive nomogram for VTE in non-surgical inpatients with T2DM was developed and validated in this study. The nomogram is highly predictive and easy to operate, but external data verification is required before it can be further used.

Assessment of the Effect on Thromboprophylaxis with Multifaceted Quality Improvement Intervention based on Clinical Decision Support System in Hospitalized Patients: A Pilot Study

Background: To explore the feasibility and effectiveness of multifaceted quality improvement intervention based on the clinical decision support system (CDSS) in VTE prophylaxis in hospitalized patients. Methods: A randomized, department-based clinical trial was conducted in the department of respiratory and critical care medicine, orthopedic, and general surgery wards. Patients aged ≥18 years, without VTE in admission, were allocated to the intervention group and received regular care combined with multifaceted quality improvement intervention based on CDSS during hospitalization. VTE prophylaxis rate and the occurrence of hospital-associated VTE events were analyzed as primary and secondary outcomes. Results: A total of 3644 eligible residents were enrolled in this trial. With the implementation of the multifaceted quality improvement intervention based on the CDSS, the VTE prophylaxis rate of the intervention group increased from 22.93% to 34.56% (p < 0.001), and the incidence of HA-VTE events increased from 0.49% to 1.00% (p = 0.366). In the nonintervention group, the VTE prophylaxis rate increased from 24.49% to 27.90% (p = 0.091), and the incidence of HA-VTE events increased from 0.47% to 2.02% (p = 0.001). Conclusions: Multifaceted quality improvement intervention based on the CDSS strategy is feasible and expected to facilitate implementation of the recommended VTE prophylaxis strategies and reduce the incidence of HA-VTE in hospital. However, it is necessary to conduct more multicenter clinical trials in the future to provide more reliable real-world evidence.

Acceptance of clinical decision support system to prevent venous thromboembolism among nurses: an extension of the UTAUT model

Background

Venous thromboembolism has been a major public health problem and caused a heavy disease burden. Venous thromboembolism clinical decision support system was proved to have a positive influence on the prevention and management of venous thromboembolism. As the direct users, nurses' acceptance of this system is of great importance to support the successful implementation of it. However, there are few relevant studies to investigate nurses' acceptance and the associated factors are still unclear.

Objective

To investigate the determinant factors of nurses' acceptance of venous thromboembolism clinical decision support system with the modified Unified Theory of Acceptance and Use of Technology.

Methods

We designed a questionnaire based on the modified Unified Theory of Acceptance and Use of Technology and then a cross-sectional survey was conducted among nurses in a tertiary hospital in Nanjing, China. Statistically, a Structural Equation Modeling -Partial Least Squares path modeling approach was applied to examine the research model.

Results

A total of 1100 valid questionnaires were recycled. The modified model explained 74.7%, 83.0% and 86% of the variance in user satisfaction, behavioral intention and user behavior, respectively. The results showed that performance expectancy (β = 0.254, p = 0.000), social influence (β = 0.136, p = 0.047), facilitating conditions (β = 0.245, p = 0.000), self-efficacy (β = 0.121, p = 0.048) and user satisfaction (β = 0.193, p = 0.001) all had significant effects on nurses' intention. Although effort expectancy (β = 0.010, p = 0.785) did not have a direct effect on nurses' intention, it could indirectly influence nurses' intention with user satisfaction as the mediator (β = 0.296, p = 0.000). User behavior was significantly predicted by facilitating conditions (β = 0.298, p = 0.000) and user intention (β = 0.654, p = 0.001).

Conclusion

The research enhances our understanding of the determinants of nurses' acceptance of venous thromboembolism clinical decision support system. Among these factors, performance expectancy was considered as the top priority. It highlights the importance of optimizing system performance to fit the users' needs. Generally, the findings in our research provide clinical technology designers and administrators with valuable information to better meet users' requirements and promote the implementation of venous thromboembolism clinical decision support system.

An update on the global use of risk assessment models and thromboprophylaxis in hospitalized patients with medical illnesses from the World Thrombosis Day steering committee: Systematic review and meta-analysis

INTRODUCTION

Venous thromboembolism (VTE) is a leading cause of cardiovascular morbidity and mortality. The majority of VTE events are hospital-associated. In 2008, the Epidemiologic International Day for the Evaluation of Patients at Risk for Venous Thromboembolism in the Acute Hospital Care Setting (ENDORSE) multinational cross-sectional study reported that only approximately 40% of medical patients at risk of VTE received adequate thromboprophylaxis.

METHODS

In our systematic review and meta-analysis, we aimed at providing updated figures concerning the use of thromboprophylaxis globally. We focused on: (a) the frequency of patients with an indication to thromboprophylaxis according with individual models; (b) the use of adequate thromboprophylaxis; and (c) reported contraindications to thromboprophylaxis. Observational nonrandomized studies or surveys focusing on medically ill patients were considered eligible.

RESULTS

After screening, we included 27 studies from 20 countries for a total of 137 288 patients. Overall, 50.5% (95% confidence interval [CI]: 41.9-59.1, I2 99%) of patients had an indication to thromboprophylaxis: of these, 54.5% (95% CI: 46.2-62.6, I2 99%) received adequate thromboprophylaxis. The use of adequate thromboprophylaxis was 66.8% in Europe (95% CI: 50.7-81.1, I2 98%), 44.9% in Africa (95% CI: 31.8-58.4, I2 96%), 37.6% in Asia (95% CI: 25.7-50.3, I2 97%), 58.3% in South America (95% CI: 31.1-83.1, I2 99%), and 68.6% in North America (95% CI: 64.9-72.6, I2 96%). No major differences in adequate thromboprophylaxis use were found across risk assessment models. Bleeding, thrombocytopenia, and renal/hepatic failure were the most frequently reported contraindications to thromboprophylaxis.

CONCLUSIONS

The use of anticoagulants for VTE prevention has been proven effective and safe, but thromboprophylaxis prescriptions are still unsatisfactory among hospitalized medically ill patients around the globe with marked geographical differences.

A Review of Current and Future Antithrombotic Strategies in Surgical Patients-Leaving the Graduated Compression Stockings Behind?

Venous thromboembolism (VTE) remains an important consideration within surgery, with recent evidence looking to refine clinical guidance. This review provides a contemporary update of existing clinical evidence for antithrombotic regimens for surgical patients, providing future directions for prophylaxis regimens and research. For moderate to high VTE risk patients, existing evidence supports the use of heparins for prophylaxis. Direct oral anticoagulants (DOACs) have been validated within orthopaedic surgery, although there remain few completed randomised controlled trials in other surgical specialties. Recent trials have also cast doubt on the efficacy of mechanical prophylaxis, especially when adjuvant to pharmacological prophylaxis. Despite the ongoing uncertainty in higher VTE risk patients, there remains a lack of evidence for mechanical prophylaxis in low VTE risk patients, with a recent systematic search failing to identify high-quality evidence. Future research on rigorously developed and validated risk assessment models will allow the better stratification of patients for clinical and academic use. Mechanical prophylaxis' role in modern practice remains uncertain, requiring high-quality trials to investigate select populations in which it may hold benefit and to explore whether intermittent pneumatic compression is more effective. The validation of DOACs and aspirin in wider specialties may permit pharmacological thromboprophylactic regimens that are easier to administer.

Pulmonary thromboembolism in hospitalised patients with COVID-19: a retrospective national study of patients managed in critical care and ward environments in Scotland

OBJECTIVES

To assess for increase in pulmonary thromboembolism (PTE) in hospitalised patients with COVID-19, in both critical care and ward environments.

SETTING

We reviewed all CT pulmonary angiograms (CTPA) performed in Scotland between 23 March 2020 and 31 May 2020 and identified those with COVID-19 using either classical radiological appearances or positive COVID-19 PCR swab.

PARTICIPANTS

All hospitalised patients in Scotland with COVID-19 between 23 March 2020 and 31 May 2020 who underwent a CTPA.

PRIMARY OUTCOME MEASURE

To assess if the rate of PTE was increased in those with COVID-19 compared with previously published figures of hospitalised patients.

SECONDARY OUTCOME MEASURES

To assess the effect of right heart strain or requirement for critical care on mortality.

RESULTS

3401 CTPAs were reviewed. 192 were positive for PTE in patients with evidence of COVID-19 either real-time PCR swab positive for SARS-CoV-2 (n=104) or having radiological changes consistent with COVID-19 (n=88). The total number of hospital admissions in Scotland between 23rd March 2020 and 31st May 2020 with COVID-19 was 5195. The incidence of PTE during this time was 3.7% in all patients admitted to all hospitals in Scotland with COVID-19 during this period. 475 hospitalised patients were managed in critical care (both level 2 and level 3 care), in whom the incidence of PTE was 6% (n=29). 4720 patients did not require admission to critical care, in whom the incidence of PTE was 3.5% (n=163). There was increased risk of death with right heart strain (25/52 vs 128/140 (p<0.01)) and in critical care (15/29 vs 146/163 (p<0.01)).

CONCLUSIONS

We have demonstrated an increased risk of PTE in critical care and ward-based environments. Further studies are required to establish effective prophylactic anticoagulation in this group.

Incidence, diagnosis, treatment methods, and outcomes of clinically suspected venous thromboembolic disease in patients with COVID-19 in a quaternary hospital in Brazil

BACKGROUND

Prothrombotic states have been associated with viral infections and the novel Sars-COV-2 infection has been associated with elevated D-dimer levels, although no causal relation has been clearly established.

OBJECTIVES

This study presents an epidemiological analysis of manifest VTE episodes in a group of patients hospitalized because of COVID-19.

METHODS

Medical records of patients who presented symptomatic deep vein thrombosis and/or pulmonary embolism in concomitance with confirmed COVID-19 were retrospectively studied. Demographic characteristics, prevalence of VTE, site of occurrence, D-dimer variation over time, management, and outcomes were analyzed.

RESULTS

During the study period, 484 confirmed cases of COVID-19 were admitted, 64 of which displayed VTE symptoms and 13 of which had confirmed symptomatic VTE(2.68% of total sample and 20.31% of symptomatic cases). Most cases (76.92%) occurred in intensive care. On the day attributed to VTE onset, D-dimer levels were over 3,000 ng/mL in 8 (80%) patients, a significant increase from baseline admission levels (p < 0.05). A significant decrease was also observed in D-dimer values at hospital discharge (p < 0.05). All patients received pharmacological thromboprophylaxis and/or anticoagulation as indicated. Two deaths occurred during the study, both patients with severe comorbidities. At the end of our study protocol, nine patients had been discharged and two remained hospitalized, but had no signs of VTE worsening.

CONCLUSIONS

VTE prevalence in hospitalized COVID-19 patients was 2.7%, and higher in intensive care units. Early institution of prophylaxis and immediate full anticoagulation when VTE is diagnosed should be the goals of those who treat this kind of patient.

Compression stockings in addition to low-molecular-weight heparin to prevent venous thromboembolism in surgical inpatients requiring pharmacoprophylaxis: the GAPS non-inferiority RCT

BACKGROUND

Patients admitted to hospital for surgery are at an increased risk of venous thromboembolism. Pharmaco-thromboprophylaxis and mechanical prophylaxis (usually graduated compression stockings or intermittent pneumatic compression) have been shown to reduce the incidence of venous thromboembolism. The evidence base supporting the National Institute for Health and Care Excellence's recommendation for the use of graduated compression stockings for venous thromboembolism prevention in the UK has recently been challenged. It is unclear if the risks and costs associated with graduated compression stockings are justified for deep-vein thrombosis prevention in moderate- and high-risk elective surgical inpatients receiving low-dose low-molecular-weight heparin pharmaco-thromboprophylaxis.

OBJECTIVES

The primary objective was to compare the venous thromboembolism rate in elective surgical inpatients at moderate or high risk of venous thromboembolism who were receiving either graduated compression stockings and low-dose low-molecular-weight heparin (standard care) or low-dose low-molecular-weight heparin alone (intervention).

DESIGN

This was a pragmatic, multicentre, prospective, non-inferiority, randomised controlled trial.

SETTING

This took place in secondary care NHS hospitals in the UK.

PARTICIPANTS

Patients aged ≥ 18 years who were assessed to be at moderate or high risk of venous thromboembolism according to the NHS England venous thromboembolism risk assessment tool (or the trust equivalent based on this form) and who were not contraindicated to low-molecular-weight heparin or graduated compression stockings were deemed eligible to take part.

INTERVENTIONS

Participants were randomised 1 : 1 to either low-molecular-weight heparin or low-molecular-weight heparin and graduated compression stockings.

MAIN OUTCOME MEASURES

The primary outcome measure was venous thromboembolism up to 90 days after surgery. A combined end point of duplex ultrasound-proven new lower-limb deep-vein thrombosis (symptomatic or asymptomatic) plus imaging-confirmed symptomatic pulmonary embolism. Secondary outcomes included quality of life, compliance with graduated compression stockings and low-molecular-weight heparin during admission, and all-cause mortality.

RESULTS

A total of 1905 participants were randomised and 1858 were included in the intention-to-treat analysis. A primary outcome event occurred in 16 out of 937 (1.7%) patients in the low-molecular-weight heparin-alone arm compared with 13 out of 921 (1.4%) patients in the low-molecular-weight heparin plus graduated compression stockings arm. The risk difference between low-molecular-weight heparin and low-molecular-weight heparin plus graduated compression stockings was 0.30% (95% confidence interval -0.65% to 1.26%). As the 95% confidence interval did not cross the non-inferiority margin of 3.5% (p < 0.001 for non-inferiority), the results indicate that non-inferiority of low-molecular-weight heparin alone was shown.

LIMITATIONS

In total, 13% of patients did not receive a duplex ultrasound scan that could have detected further asymptomatic deep-vein thrombosis. However, missing scans were balanced between both trial arms. The subpopulation of those aged ≥ 65 years assessed as being at a moderate risk of venous thromboembolism was under-represented in the study; however, this reflects that this group is under-represented in the general population.

CONCLUSIONS

For elective surgical patients at moderate or high risk of venous thromboembolism, administration of pharmaco-thromboprophylaxis alone is non-inferior to a combination of pharmaco-thromboprophylaxis and graduated compression stockings. These findings indicate that graduated compression stockings may be unnecessary for most elective surgical patients.

FUTURE WORK

Further studies are required to evaluate whether or not adjuvant graduated compression stockings have a role in patients receiving extended thromboprophylaxis, beyond the period of hospital admission, following elective surgery or in patients undergoing emergency surgical procedures.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN13911492.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 69. See the NIHR Journals Library website for further project information.

Awareness and Prophylaxis of Venous Thromboembolism in Patients with COVID-19: A National Cross-Sectional Survey in Epidemic Era

Aim: Patients with acute infectious diseases are at an increased risk of venous thromboembolism (VTE). Clinicians should be aware of the VTE risk in patients with COVID-19, many of whom present with severe coagulation disorders.

Method: We used an online platform to conduct a cross-sectional questionnaire survey among doctors in mainland China in March 2020. The questionnaire was designed to figure out the clinician's current awareness of VTE prevention and detection rates, as well as the current status of VTE prophylaxis in patients with COVID-19.

Results: We collected 1,636 replies, of which 1,579 were valid. Among these, 991 (63%) clinicians were involved directly in frontline treatment. Most of the clinicians (1,492, or 94%) thought it was necessary to assess the VTE risk in patients with COVID-19. However, only 234 (24%) clinicians performed appropriate assessment during the COVID-19 outbreak. For patients with mild/moderate COVID-19, 752 (76%) clinicians would prescribe exercise and water to prevent VTE. For patients with severe COVID-19, 448 (45%) clinicians would prescribe mechanical devices if the patient had a high bleeding risk, and 648 (65%) clinicians would choose LMWH as prophylaxis if the patient had a low bleeding risk. The VTE detection rate was not that high in both mild/moderate and severe patients.

Conclusion: Although most clinicians recommended prescribing VTE prophylaxis to patients with COVID-19, the practice still needs to be improved. A real-world registry to investigate the true incidence of VTE, and the effect of prescribing appropriate prophylaxis for patients with COVID-19, is necessary in the future.

Effect on thromboprophylaxis among hospitalized patients using a system-wide multifaceted quality improvement intervention: Rationale and design for a multicenter cluster randomized clinical trial in China

BACKGROUND

Venous thromboembolism (VTE) is a life-threatening disease that can affect each hospitalized patient. But the current in-hospital thromboprophylaxis remains suboptimal and there exists a large gap between clinical practice and guideline-recommended care in China.

METHODS

To facilitate implementation of guideline recommendations, we conduct a multicenter, adjudicator-blinded, cluster-randomized clinical trial, aiming to assess the effectiveness of a system-wide multifaceted quality improvement (QI) strategy on VTE prophylaxis improvement and thromboembolism reduction in clinical setting. Hospitals are randomized into intervention or control group. In intervention group, hospitals receive the concept of appropriate in-hospital thromboprophylaxis plus a multifaceted QI which encompasses four components: (1) an electronic alert combining computer-based clinical decision support system and electronic reminders, (2) appropriate prophylaxis based on dynamic VTE and bleeding risk assessments, (3) periodical audit and interactive feedback on performance, (4) strengthened training and patient education. In control, hospitals receive the concept of recommended prophylaxis alone without QI. Thromboprophylaxis will be at the discretion of hospitals and conducted as usual. With a final sample size of 5760 hospitalized patients in 32 hospitals on mainland China, this trial will examine the effect of QI on improvement in thromboprophylaxis and patient-centered outcomes. This is an open-label trial that patients and healthcare professionals will know group allocation after enrollment, but endpoint adjudicators and statisticians will be blinded. RCT# NCT04211181 CONCLUSIONS: The system-wide multifaceted QI intervention is expected to facilitate implementation of recommended VTE prophylaxis in hospital, thereafter reducing VTE incidence and relevant adverse events among hospitalized patients in China.

Graduated compression stockings as adjuvant to pharmaco-thromboprophylaxis in elective surgical patients (GAPS study): randomised controlled trial

OBJECTIVES

To investigate whether the use of graduated compression stockings (GCS) offers any adjuvant benefit when pharmaco-thromboprophylaxis is used for venous thromboembolism prophylaxis in patients undergoing elective surgery.

DESIGN

Open, multicentre, randomised, controlled, non-inferiority trial.

SETTING

Seven National Health Service tertiary hospitals in the United Kingdom.

PARTICIPANTS

1905 elective surgical inpatients (≥18 years) assessed as being at moderate or high risk of venous thromboembolism were eligible and consented to participate.

INTERVENTION

Participants were randomly assigned (1:1) to receive low molecular weight heparin (LMWH) pharmaco-thromboprophylaxis alone or LMWH pharmaco-thromboprophylaxis and GCS.

OUTCOME MEASURES

The primary outcome was imaging confirmed lower limb deep vein thrombosis with or without symptoms, or pulmonary embolism with symptoms within 90 days of surgery. Secondary outcome measures were quality of life, compliance with stockings and LMWH, lower limb complications related to GCS, bleeding complications, adverse reactions to LMWH, and all cause mortality.

RESULTS

Between May 2016 and January 2019, 1905 participants were randomised. 1858 were included in the intention to treat analysis (17 were identified as ineligible after randomisation and 30 did not undergo surgery). A primary outcome event occurred in 16 of 937 (1.7%) patients in the LMWH alone group compared with 13 of 921 (1.4%) in the LMWH and GCS group. The risk difference between the two groups was 0.30% (95% confidence interval -0.65% to 1.26%). Because the 95% confidence interval did not cross the non-inferiority margin of 3.5% (P<0.001 for non-inferiority), LMWH alone was confirmed to be non-inferior.

CONCLUSIONS

For patients who have elective surgery and are at moderate or high risk of venous thromboembolism, administration of pharmaco-thromboprophylaxis alone is non-inferior to a combination of pharmaco-thromboprophylaxis and GCS. These findings indicate that GCS might be unnecessary in most patients undergoing elective surgery.

TRIAL REGISTRATION

ISRCTN13911492.