Unmet needs and barriers in venous thromboembolism education and awareness among people living with cancer: a global survey

BACKGROUND

Venous thromboembolism (VTE) is a major preventable cause of morbidity, disability, and mortality in subjects with cancer. A global appraisal of cancer-associated VTE education and awareness is not available.

OBJECTIVES

To evaluate VTE-related education, awareness, and unmet needs from the perspective of people living with cancer using a quantitative and qualitative approach.

METHODS

This cross-sectional study used data from an online-based survey covering multidimensional domains of cancer-associated VTE. Data are presented descriptively. Potential differences across participant subgroups were explored.

RESULTS

Among 2262 patients with cancer from 42 countries worldwide, 55.3% received no VTE education throughout their cancer journey, and an additional 8.2% received education at the time of VTE diagnosis only, leading to 63.5% receiving no or inappropriately delayed education. When education was delivered, only 67.8% received instructions to seek medical attention in case of VTE suspicion, and 36.9% reported scarce understanding. One-third of participants (32.4%) felt psychologically distressed when becoming aware of the potential risks and implications connected with cancer-associated VTE. Most responders (78.8%) deemed VTE awareness highly relevant, but almost half expressed concerns about the quality of education received. While overall consistent, findings in selected survey domains appeared to numerically differ across age group, ethnicity, continent of residence, educational level, metastatic status, and VTE history.

CONCLUSION

This study involving a large and diverse population of individuals living with cancer identifies important unmet needs in VTE-related education, awareness, and support across healthcare systems globally. These findings unveil multilevel opportunities to expedite patient-centered care in cancer-associated VTE prevention and management.

VTE risk assessment, prevention and diagnosis in pregnancy

Venous thromboembolism (VTE) is still reported as the leading cause of direct maternal death in pregnancy in serial international reports in developed countries. VTE risk is higher during pregnancy but is further increased by additional well-characterized risk factors. International guidelines recommend that formal VTE risk assessment should be conducted at least in early pregnancy, at delivery and when risk factors change. High quality data supporting optimal VTE prevention strategies are lacking, outside the setting of prevention of VTE recurrence. Moreover, recent high-quality studies have provided much-needed data on diagnostic strategies for pulmonary embolism (PE) in pregnancy. In this review, we summarize knowledge gaps and recently published data in the prevention and diagnosis of VTE in pregnancy. Moreover, we describe ongoing high-quality randomised trials and prospective clinical management studies in this area. High quality clinical studies and trials in pregnancy can be done and must be prioritised, through international network efforts and national funding advocacy. Ultimately, translation of study results to impact upon guidelines and policy will deliver better care to and will protect the lives and health of pregnant people and those contemplating pregnancy throughout the world.

The effect of UVA light/8-methoxypsoralen exposure used in Extracorporeal Photopheresis treatment on platelets and extracellular vesicles

Extracorporeal Photopheresis (ECP) is a leukapheresis based treatment for Cutaneous T-Cell Lymphoma, which takes advantage of the cellular lethal effects of UVA light in combination with a photoactivated drug, 8-methoxypsoralen. 25% of patients treated with ECP do not respond to treatment, however the underlying mechanisms for this lack of response remain unknown. Platelets, a rich source of extracellular vesicles (EVs) and key mediators in thromboinflammatory oncological progression, as well as leukocytes, are both processed through ECP and are subsequently transfused back into the patient, delivering potent immunomodulation. The effect of exposing platelets and their EVs directly to Ultra Violet A light (UVA)/8-methoxypsoralen is currently unknown. Platelet-rich plasma (PRP) was isolated from healthy donors and exposed to UVA light and/or 8-methoxysporalen in vitro and platelet activation and aggregation was assessed. EV size and concentration were also characterised by Nanoparticle Tracking Analysis and Flow Cytometry. We found that UVA light and 8-methoxypsoralen treatment in vitro does not induce platelet aggregation or significantly alter levels of the platelet activation markers, soluble P-selectin or platelet factor 4, with circulating levels of small and large EV size and concentration remaining constant. Therefore, utilising the combination of UVA light and 8-methoxypsoralen used in ECP in vitro does not activate platelets or alter important circulating EVs. Further studies will be needed to validate if our observations are consistent in vivo.

VTE Risk Assessment and Prevention in Pregnancy

Venous thromboembolism (VTE) remains the leading cause of maternal mortality in pregnancy and the postpartum period. In addition to the higher pregnancy-associated baseline VTE risk, there are several well-established risk factors that can further increase the risk of VTE. At present, a thorough interrogation of these risk factors remains our only tool for estimating which pregnant people may be at an increased risk of VTE, and thus potentially benefit from thromboprophylaxis. However, an important knowledge gap still exists surrounding the duration of increased risk and the interaction of risk factors with each other. Furthermore, up to now, once significant risk has been established, prevention strategies have been largely based on expert opinion rather than high-quality data. Recent trials have successfully bridged a proportion of this knowledge gap; however, the challenge of conducting high-quality clinical trials with pregnant people remains. In this article, we provide an update on the recent evidence surrounding VTE risk factors in pregnancy while concurrently outlining knowledge gaps and current approaches to VTE prevention.

Markers of platelet activation foR identification of late onset sEpsis in infaNTs: PARENT study protocol

BACKGROUND

Newborns are at high risk of sepsis. At present there is no definitive "rule in" blood test for sepsis at the point of clinical concern. A positive blood culture remains the gold standard test for neonatal sepsis, however laboratory markers that correlate prospectively with culture positive sepsis could aid clinicians in making decisions regarding administration of empiric antibiotic therapies.

METHODS

This multi-site, prospective observational study will take place in two neonatal intensive care units (National Maternity Hospital and Rotunda Hospital, Dublin). Neonates born at less than 34 weeks will be enroled and informed consent obtained prior to late onset sepsis work up. If at any point subsequently during their neonatal intensive care stay they develop signs and symptoms of possible sepsis requiring blood culture, an additional sodium citrate sample will be obtained. Infants will be categorised into three groups as follows: (i) culture positive sepsis, (ii) culture negative sepsis where an infant receives 5 days of antibiotics (iii) non sepsis. Our primary outcome is to establish if differential platelet/endothelial activation can prospectively identify neonatal culture positive late onset sepsis.

TRIAL REGISTRATION NUMBER

NCT05530330 IMPACT: Preterm infants are a high risk group for the development of sepsis which is a major cause of mortality in this population. Platelets have been associated with host response to invasive bacterial infections both in animal models and translational work. A positive blood culture is the gold standard test for neonatal sepsis but can be unreliable due to limited blood sampling in the very low birth weight population. This study hopes to establish if platelet/endothelial associated plasma proteins can prospectively identify late onset neonatal sepsis.

Retrospective cross-sectional analysis of concurrent VTE diagnosis in hospitalised socially excluded individuals in Ireland

OBJECTIVE

Social exclusion (such as that experienced by people who are homeless, incarcerated or use drugs) increases morbidity across a range of diseases but is poorly captured in routine data sets. The aim of this study was to use a novel composite variable in a national-level hospital usage dataset to identify social exclusion and to determine whether social exclusion is associated with concurrent venous thromboembolism (VTE) in hospitalised patients in Ireland. Identifying and characterising this association in people who are socially excluded will inform VTE prevention and treatment strategies.

DESIGN

Retrospective cross-sectional study.

SETTING

Irish Hospital Inpatient Enquiry (HIPE) system, which collects diagnostic information by International Classification of Diseases Tenth Revision code on all hospital admission episodes in the Ireland.

PARTICIPANTS

All hospital admission episodes involving a VTE diagnosis (in a primary 'Dx 1' or secondary 'Dx 2-30' coding position) during a 12-month period in the Ireland were identified from consolidated, national-level datasets derived from the Irish HIPE system. Social exclusion was defined as the presence of one or more indicators of homelessness, drug use, incarceration, health hazards due to socioeconomic status or episodes of healthcare terminated prematurely.

RESULTS

Of 5701 admission episodes involving a VTE diagnosis (in a primary or secondary position) during the study period, 271 (4.8%) related to an individual affected by social exclusion. Among hospitalised individuals identified as being socially excluded based on the novel composite variable, the likelihood of having a concurrent VTE diagnosis was over twofold greater than that observed in the general population (OR 2.14, 95% CI 1.79 to 2.26; p<0.001).

CONCLUSION

These data suggest that VTE (primary and secondary) is over-represented in hospitalised socially excluded persons in Ireland and that the development of strategies to address this potentially life-threatening accompanying condition in this vulnerable patient group must be prioritised.

Proteomic analysis of extracellular vesicle cargoes mirror the cardioprotective effects of rivaroxaban in patients with venous thromboembolism

BACKGROUND

Venous thromboembolism (VTE) remains a significant cause of morbidity and mortality worldwide. Rivaroxaban, a direct oral factor Xa inhibitor, mediates anti-inflammatory and cardiovascular-protective effects besides its well-established anticoagulant properties; yet, these remain poorly characterized. Extracellular vesicles (EVs) are considered proinflammatory messengers regulating a myriad of (patho)physiological processes and may be highly relevant to the pathophysiology of VTE. The effects of Rivaroxaban on circulating EVs in VTE patients remain unknown. We have established that differential EV biosignatures are found in patients with non-valvular atrial fibrillation anticoagulated with Rivaroxaban versus warfarin. Here, we investigated whether differential proteomic profiles of circulating EVs could also be found in patients with VTE.

METHODS AND RESULTS

We performed comparative label-free quantitative proteomic profiling of enriched plasma EVs from VTE patients anticoagulated with either Rivaroxaban or warfarin using a tandem mass spectrometry approach. Of the 182 quantified proteins, six were found to be either exclusive to, or enriched in, Rivaroxaban-treated patients. Intriguingly, these proteins are involved in negative feedback regulation of inflammatory and coagulation pathways, suggesting that EV proteomic signatures may reflect both Rivaroxaban's anti-coagulatory and anti-inflammatory potential.

CONCLUSIONS

These differences suggest Rivaroxaban may have pleiotropic effects, supporting the reports of its emerging anti-inflammatory and cardiovascular-protective characteristics relative to warfarin.

Prevention, diagnosis, and management of PE and DVT in pregnant women

Venous thromboembolism (VTE) is a leading cause of maternal morbidity and mortality worldwide. Despite the impact of VTE on pregnant and postpartum people and on society, guidelines addressing prevention, diagnosis, and management of VTE in pregnant and postpartum people frequently are based on recommendations from expert opinion and are extrapolated from data in nonpregnant populations. Pregnant individuals are frequently excluded from clinical trials, which is a barrier to providing safe, effective care. Anchoring to a case discussion, this review provides an update on recently published and ongoing randomized clinical trials (RCTs), prospective clinical management studies, and other research in this area. It highlights, in particular, the results of the Highlow RCT, which addresses optimal prevention of recurrence during pregnancy in people with prior VTE. Finally, we raise awareness of the impact of national and international clinical trial networks on the conduct of RCTs in pregnancy. We conclude, based on these data, that academic VTE clinical trials in pregnant women can and must be done.

Platelet proteo-transcriptomic profiling validates mediators of thrombosis and proteostasis in patients with myeloproliferative neoplasms

Patients with chronic Myeloproliferative Neoplasms (MPN) including polycythemia vera (PV) and essential thrombocythemia (ET) exhibit unique clinical features, such as a tendency toward thrombosis and hemorrhage, and risk of disease progression to secondary bone marrow fibrosis and/or acute leukemia. Although an increase in blood cell lineage counts (quantitative features) contribute to these morbid sequelae, the significant qualitative abnormalities of myeloid cells that contribute to vascular risk are not well understood. Here, we address this critical knowledge gap via a comprehensive and untargeted profiling of the platelet proteome in a large (n= 140) cohort of patients (from two independent sites) with an established diagnosis of PV and ET (and complement prior work on the MPN platelet transcriptome from a third site). We discover distinct MPN platelet protein expression and confirm key molecular impairments associated with proteostasis and thrombosis mechanisms of potential relevance to MPN pathology. Specifically, we validate expression of high-priority candidate markers from the platelet transcriptome at the platelet proteome (e.g., calreticulin (CALR), Fc gamma receptor (FcγRIIA) and galectin-1 (LGALS1) pointing to their likely significance in the proinflammatory, prothrombotic and profibrotic phenotypes in patients with MPN. Together, our proteo-transcriptomic study identifies the peripherally-derived platelet molecular profile as a potential window into MPN pathophysiology and demonstrates the value of integrative multi-omic approaches in gaining a better understanding of the complex molecular dynamics of disease.

Antagonistic Roles of Human Platelet Integrin αIIbβ3 and Chemokines in Regulating Neutrophil Activation and Fate on Arterial Thrombi Under Flow

BACKGROUND

Platelets and neutrophils are the first blood cells accumulating at sites of arterial thrombus formation, and both cell types contribute to the pathology of thrombotic events. We aimed to identify key interaction mechanisms between these cells using microfluidic approaches.

METHODS

Whole-blood perfusion was performed over a collagen surface at arterial shear rate. Platelet and leukocyte (in majority neutrophil) activation were microscopically visualized using fluorescent markers. The contributions of platelet-adhesive receptors (integrin, P-selectin, CD40L) and chemokines were studied by using inhibitors or antibodies and using blood from patients with GT (Glanzmann thrombasthenia) lacking platelet-expressed αIIbβ3.

RESULTS

We observed (1) an unknown role of activated platelet integrin αIIbß3 preventing leukocyte adhesion, which was overcome by short-term flow disturbance provoking massive adhesion; (2) that platelet-expressed CD40L controls the crawling pattern and thrombus fidelity of the cells on a thrombus; (3) that continued secretion of platelet substances promotes activation of identified neutrophils, as assessed by (fMLP [N-formylmethionyl-leucyl-phenylalanine, a potent chemotactic agent and leukocyte activator] induced) [Ca2+]i rises and antigen expression; (4) and that platelet-released chemokines activate the adhered cells in the order of CXCL7>CCL5>CXCL4. Furthermore, postsilencing of the platelets in a thrombus suppressed the leukocyte activation. However, the leukocytes on thrombi did no more than limitedly form neutrophil extracellular traps, unless stimulated with phorbol ester or lipopolysaccharide.

CONCLUSIONS

Together, these findings reveal a multifaceted regulation of adhesion and activation of neutrophils by platelets in a thrombus, with a balanced role of several platelet-adhesive receptors and a promoting role of platelet-released substances. This multivalent nature of neutrophil-thrombus interactions offers novel prospects for pharmacological intervention.

An optimized protocol to isolate quiescent washed platelets from human whole blood and generate platelet releasate under clinical conditions

The contents of the platelet releasate (PR) play significant roles in hemostasis, inflammation, and pathologic sequelae. Careful platelet isolation to ensure quiescence and subsequent activation is key to the successful generation of PR. Here, we describe steps to isolate and aggregate quiescent washed platelets from whole blood of a clinical patient cohort. We then detail the generation of PR from isolated human washed platelets under clinical conditions. This protocol allows the investigation of platelet cargoes released through various activation pathways.

Onset of labor and use of analgesia in women using thromboprophylaxis with 2 doses of low-molecular-weight heparin: insights from the Highlow study

BACKGROUND

Peripartum management of women using low-molecular-weight heparin (LMWH) varies widely. Minimum time intervals are required between LMWH injection and neuraxial procedure, and they differ by dose.

OBJECTIVES

The objective of this study was to describe the onset of labor and use of analgesia in women using LMWH and to compare practices between intermediate-dose and low-dose LMWH.

METHODS

In the Highlow study (NCT01828697), 1110 women were randomized to intermediate-dose or low-dose LMWH and were instructed to discontinue LMWH when labor commenced unplanned or 24 hours prior to planned delivery. The required time interval since last injection to receive a neuraxial procedure was ≥24 hours for intermediate-dose LMWH or ≥12 hours for low-dose LMWH.

RESULTS

In total, 1018 women had an ongoing pregnancy for ≥24 weeks. Onset of labor was spontaneous in 198 of 509 (39%) women on intermediate-dose LMWH and in 246 of 509 (49%) on low-dose LMWH. With unplanned onset, a neuraxial procedure was performed in 37% on intermediate-dose and in 48% on low-dose LMWH (risk difference -11%, 95% CI -20% to -2%). Based on time interval, 61% on intermediate-dose and 82% on low-dose LMWH were eligible for a neuraxial procedure. With planned onset, 68% on intermediate-dose and 66% on low-dose LMWH received a neuraxial procedure, whereas 81% and 93%, respectively, were eligible for a neuraxial procedure (risk difference -13%, 95% CI -18% to -8%).

CONCLUSION

With spontaneous onset of labor, neuraxial procedures were performed less often in women using intermediate-dose LMWH. Irrespective of onset, fewer women on intermediate-dose LMWH than those on low-dose LMWH were eligible for neuraxial procedures based on required time intervals since the last LMWH injection.

Management of Hemorrhage During Cesarean Delivery in a Patient With Vascular Ehlers-Danlos Syndrome: A Case Report

Parturients with vascular Ehlers-Danlos syndrome are at particular risk of hemorrhage, and there is little evidence to guide prevention or management of hemorrhage in these patients. We present the case of a patient with vascular Ehlers-Danlos syndrome who had a cesarean delivery complicated by an intraoperative hemorrhage. Administration of desmopressin and tranexamic acid appeared to be of marked benefit in achieving hemostasis. To the best of our knowledge, this is the first report of the use of desmopressin during major obstetric hemorrhage in vascular Ehlers-Danlos syndrome.

Intermediate-dose versus low-dose low-molecular-weight heparin in pregnant and post-partum women with a history of venous thromboembolism (Highlow study): an open-label, multicentre, randomised, controlled trial

BACKGROUND

Pregnancy-related venous thromboembolism is a leading cause of maternal morbidity and mortality, and thromboprophylaxis is indicated in pregnant and post-partum women with a history of venous thromboembolism. The optimal dose of low-molecular-weight heparin to prevent recurrent venous thromboembolism in pregnancy and the post-partum period is uncertain.

METHODS

In this open-label, randomised, controlled trial (Highlow), pregnant women with a history of venous thromboembolism were recruited from 70 hospitals in nine countries (the Netherlands, France, Ireland, Belgium, Norway, Denmark, Canada, the USA, and Russia). Women were eligible if they were aged 18 years or older with a history of objectively confirmed venous thromboembolism, and with a gestational age of 14 weeks or less. Eligible women were randomly assigned (1:1), before 14 weeks of gestational age, using a web-based system and permuted block randomisation (block size of six), stratified by centre, to either weight-adjusted intermediate-dose or fixed low-dose low-molecular-weight heparin subcutaneously once daily until 6 weeks post partum. The primary efficacy outcome was objectively confirmed venous thromboembolism (ie, deep-vein thrombosis, pulmonary embolism, or unusual site venous thrombosis), as determined by an independent central adjudication committee, in the intention-to-treat (ITT) population (ie, all women randomly assigned to treatment). The primary safety outcome was major bleeding which included antepartum, early post-partum (within 24 h after delivery), and late post-partum major bleeding (24 h or longer after delivery until 6 weeks post partum), assessed in all women who received at least one dose of assigned treatment and had a known end of treatment date. This study is registered with ClinicalTrials.gov, NCT01828697, and is now complete.

FINDINGS

Between April 24, 2013, and Oct 31, 2020, 1339 pregnant women were screened for eligibility, of whom 1110 were randomly assigned to weight-adjusted intermediate-dose (n=555) or fixed low-dose (n=555) low-molecular-weight heparin (ITT population). Venous thromboembolism occurred in 11 (2%) of 555 women in the weight-adjusted intermediate-dose group and in 16 (3%) of 555 in the fixed low-dose group (relative risk [RR] 0·69 [95% CI 0·32-1·47]; p=0·33). Venous thromboembolism occurred antepartum in five (1%) women in the intermediate-dose group and in five (1%) women in the low-dose group, and post partum in six (1%) women and 11 (2%) women. On-treatment major bleeding in the safety population (N=1045) occurred in 23 (4%) of 520 women in the intermediate-dose group and in 20 (4%) of 525 in the low-dose group (RR 1·16 [95% CI 0·65-2·09]).

INTERPRETATION

In women with a history of venous thromboembolism, weight-adjusted intermediate-dose low-molecular-weight heparin during the combined antepartum and post-partum periods was not associated with a lower risk of recurrence than fixed low-dose low-molecular-weight heparin. These results indicate that low-dose low-molecular-weight heparin for thromboprophylaxis during pregnancy is the appropriate dose for the prevention of pregnancy-related recurrent venous thromboembolism.

FUNDING

French Ministry of Health, Health Research Board Ireland, GSK/Aspen, and Pfizer.

Risk factors, diagnosis and management of venous thromboembolic disease in pregnancy

Venous thromboembolism (VTE) in pregnancy is a leading cause of maternal morbidity and mortality. However, despite the significant associated clinical burden and potentially devastating societal impact, there is still a paucity of data surrounding its prevention and management. Consequently, international guideline recommendations vary widely. Exclusion of pregnant women from clinical trials in the past has contributed to knowledge gaps. However, recently published and ongoing studies demonstrate that excellent clinical trials in pregnancy are achievable. This review will discuss prevention, diagnosis and treatment of VTE in pregnancy, and will also explore priorities for future research.

Venous thromboembolism in pregnancy is a leading cause of maternal morbidity and mortality. However, individualised clinical risk assessment and recent advances in clinical prediction rules for pulmonary embolism have the potential to improve management.https://bit.ly/3mjtHg2

Non-severe COVID-19 is associated with endothelial damage and hypercoagulability despite pharmacological thromboprophylaxis

BACKGROUND

Hypercoagulability and endothelial dysfunction are hallmarks of coronavirus disease 2019 (COVID-19) and appear to predict disease severity. A high incidence of thrombosis despite thromboprophylaxis is reported in patients with moderate to severe COVID-19. Recent randomized clinical trials suggest that therapeutic-intensity heparin confers a survival benefit in moderate-severity COVID-19 compared to standard-intensity heparin, potentially by harnessing heparin-mediated endothelial-stabilizing and anti-inflammatory effects.

OBJECTIVE

We hypothesized that patients with moderate-severity COVID-19 exhibit enhanced hypercoagulability despite standard-intensity thromboprophylaxis with low molecular weight heparin (LMWH) compared to non-COVID-19 hospitalized patients.

METHODS

Patients with moderate COVID-19 and a control group (severe acute respiratory syndrome coronavirus 2 [SARS-CoV-2]-negative hospitalized patients) receiving LMWH thromboprophylaxis were recruited. Markers of endothelial damage and plasma thrombin generation parameters were assessed.

RESULTS

Tissue plasminogen activator levels were significantly increased in the COVID-19 group (8.3 ± 4.4 vs. 4.9 ± 2.4 ng/ml; P = .02) compared to non-COVID-19-hospitalized patients. Despite thromboprophylaxis, mean endogenous thrombin potential was significantly increased among COVID-19 patients (1929 ± 448 vs. 1528 ± 460.8 nM*min; P = .04) but lag time to thrombin generation was significantly prolonged (8.1 ± 1.8 vs. 6.2 ± 1.8 mins; P = .02). While tissue factor pathway inhibitor (TFPI) levels were similar in both groups, in the presence of an inhibitory anti-TFPI antibody, the difference in lag time between the groups was abrogated.

CONCLUSIONS

Collectively, these data demonstrate that COVID-19 of moderate severity is associated with increased plasma thrombin generation and endothelial damage, and that hypercoagulability persists despite standard LMWH thromboprophylaxis. These findings may be of clinical interest given recent clinical trial data which suggest escalated heparin dosing in non-severe COVID-19 may be associated with improved clinical outcomes.

Case Report: Hypergranular Platelets in Vaccine-Induced Thrombotic Thrombocytopenia After ChAdOx1 nCov-19 Vaccination

Background

Vaccine-induced thrombotic thrombocytopenia (VITT) post SARS-CoV-2 vaccination is characterized by thrombocytopenia and severe thrombosis. Platelet function during patient recovery in the medium-/long-term has not been investigated fully. Here, we undertook a 3-month study, assessing the recovery of a VITT patient and assessing platelet morphology, granule content and dense-granule release at two distinct time points during recovery.

Case Presentation

A 61 year-old female was admitted to hospital 15 days post ChAdOx1 nCov-19 vaccination. Hematological parameters and peripheral blood smears were monitored over 3 months. Platelet morphology and granule populations were assessed using transmission electron microscopy (TEM) at two distinct time points during recovery, as was agonist-induced platelet dense-granule release. Upon admission, the patient had reduced platelet counts, increased D-dimer and high anti-PF4 antibodies with multiple sites of cerebral venous sinus thrombosis (CVST). Peripheral blood smears revealed the presence of large, hypergranular platelets. Following treatment, hematological parameters returned to normal ranges over the study period. Anti-PF4 antibodies remained persistently high up to 90 days post-admission. Two days after admission, VITT platelets contained more granules per-platelet when compared to day 72 and healthy platelets. Additionally, maximal ATP release (marker of dense-granule release) was increased on day 2 compared to day 72 and healthy control platelets.

Conclusion

This study highlights a previously unreported observation of platelet hypergranularity in VITT which may contribute to the thrombotic risk associated with VITT. Optimal approaches to monitoring recovery from VITT over time remains to be determined but our findings may help inform therapeutic decisions relating to anticoagulation treatment in this novel pathology.

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.

Optimal follow-up after acute pulmonary embolism: a position paper of the European Society of Cardiology Working Group on Pulmonary Circulation and Right Ventricular Function, in collaboration with the European Society of Cardiology Working Group on Atherosclerosis and Vascular Biology, endorsed by the European Respiratory Society

This position paper provides a comprehensive guide for optimal follow-up of patients with acute pulmonary embolism (PE), covering multiple relevant aspects of patient counselling. It serves as a practical guide to treating patients with acute PE complementary to the formal 2019 European Society of Cardiology guidelines developed with the European Respiratory Society. We propose a holistic approach considering the whole spectrum of serious adverse events that patients with acute PE may encounter on the short and long run. We underline the relevance of assessment of modifiable risk factors for bleeding, of acquired thrombophilia and limited cancer screening (unprovoked PE) as well as a dedicated surveillance for the potential development of chronic thromboembolic pulmonary hypertension as part of routine practice; routine testing for genetic thrombophilia should be avoided. We advocate the use of outcome measures for functional outcome and quality of life to quantify the impact of the PE diagnosis and identify patients with the post-PE syndrome early. Counselling patients on maintaining a healthy lifestyle mitigates the risk of the post-PE syndrome and improves cardiovascular prognosis. Therefore, we consider it important to discuss when and how to resume sporting activities soon after diagnosing PE. Additional patient-relevant topics that require Focused counselling are travel and birth control.

Randomized trials of therapeutic heparin for COVID-19: A meta-analysis

BACKGROUND

Pulmonary endothelial injury and microcirculatory thromboses likely contribute to hypoxemic respiratory failure, the most common cause of death, in patients with COVID-19. Randomized controlled trials (RCTs) suggest differences in the effect of therapeutic heparin between moderately and severely ill patients with COVID-19. We did a systematic review and meta-analysis of RCTs to determine the effects of therapeutic heparin in hospitalized patients with COVID-19.

METHODS

We searched PubMed, Embase, Web of Science, medRxiv, and medical conference proceedings for RCTs comparing therapeutic heparin with usual care, excluding trials that used oral anticoagulation or intermediate doses of heparin in the experimental arm. Mantel-Haenszel fixed-effect meta-analysis was used to combine odds ratios (ORs).

RESULTS AND CONCLUSIONS

There were 3 RCTs that compared therapeutic heparin to lower doses of heparin in 2854 moderately ill ward patients, and 3 RCTs in 1191 severely ill patients receiving critical care. In moderately ill patients, there was a nonsignificant reduction in all-cause death (OR, 0.76; 95% CI, 0.57-1.02), but significant reductions in the composite of death or invasive mechanical ventilation (OR, 0.77; 95% CI, 0.60 0.98), and death or any thrombotic event (OR, 0.58; 95% CI, 0.45-0.77). Organ support-free days alive (OR, 1.29; 95% CI, 1.07-1.57) were significantly increased with therapeutic heparin. There was a nonsignificant increase in major bleeding. In severely ill patients, there was no evidence for benefit of therapeutic heparin, with significant treatment-by-subgroup interactions with illness severity for all-cause death (P = .034). In conclusion, therapeutic heparin is beneficial in moderately ill patients but not in severely ill patients hospitalized with COVID-19.

Effectiveness of therapeutic heparin versus prophylactic heparin on death, mechanical ventilation, or intensive care unit admission in moderately ill patients with covid-19 admitted to hospital: RAPID randomised clinical trial

OBJECTIVE

To evaluate the effects of therapeutic heparin compared with prophylactic heparin among moderately ill patients with covid-19 admitted to hospital wards.

DESIGN

Randomised controlled, adaptive, open label clinical trial.

SETTING

28 hospitals in Brazil, Canada, Ireland, Saudi Arabia, United Arab Emirates, and US.

PARTICIPANTS

465 adults admitted to hospital wards with covid-19 and increased D-dimer levels were recruited between 29 May 2020 and 12 April 2021 and were randomly assigned to therapeutic dose heparin (n=228) or prophylactic dose heparin (n=237).

INTERVENTIONS

Therapeutic dose or prophylactic dose heparin (low molecular weight or unfractionated heparin), to be continued until hospital discharge, day 28, or death.

MAIN OUTCOME MEASURES

The primary outcome was a composite of death, invasive mechanical ventilation, non-invasive mechanical ventilation, or admission to an intensive care unit, assessed up to 28 days. The secondary outcomes included all cause death, the composite of all cause death or any mechanical ventilation, and venous thromboembolism. Safety outcomes included major bleeding. Outcomes were blindly adjudicated.

RESULTS

The mean age of participants was 60 years; 264 (56.8%) were men and the mean body mass index was 30.3 kg/m². At 28 days, the primary composite outcome had occurred in 37/228 patients (16.2%) assigned to therapeutic heparin and 52/237 (21.9%) assigned to prophylactic heparin (odds ratio 0.69, 95% confidence interval 0.43 to 1.10; P=0.12). Deaths occurred in four patients (1.8%) assigned to therapeutic heparin and 18 patients (7.6%) assigned to prophylactic heparin (0.22, 0.07 to 0.65; P=0.006). The composite of all cause death or any mechanical ventilation occurred in 23 patients (10.1%) assigned to therapeutic heparin and 38 (16.0%) assigned to prophylactic heparin (0.59, 0.34 to 1.02; P=0.06). Venous thromboembolism occurred in two patients (0.9%) assigned to therapeutic heparin and six (2.5%) assigned to prophylactic heparin (0.34, 0.07 to 1.71; P=0.19). Major bleeding occurred in two patients (0.9%) assigned to therapeutic heparin and four (1.7%) assigned to prophylactic heparin (0.52, 0.09 to 2.85; P=0.69).

CONCLUSIONS

In moderately ill patients with covid-19 and increased D-dimer levels admitted to hospital wards, therapeutic heparin was not significantly associated with a reduction in the primary outcome but the odds of death at 28 days was decreased. The risk of major bleeding appeared low in this trial.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04362085.

Nonvalvular atrial fibrillation patients anticoagulated with rivaroxaban compared with warfarin exhibit reduced circulating extracellular vesicles with attenuated pro-inflammatory protein signatures

BACKGROUND

Rivaroxaban, a direct oral factor Xa inhibitor, mediates anti-inflammatory and cardiovascular-protective effects besides its well-established anticoagulant properties; however, these remain poorly characterized. Extracellular vesicles (EVs) are important circulating messengers regulating a myriad of biological and pathological processes and may be highly relevant to the pathophysiology of atrial fibrillation as they reflect alterations in platelet and endothelial biology. However, the effects of rivaroxaban on circulating pro-inflammatory EVs remain unknown.

OBJECTIVES

We hypothesized that rivaroxaban's anti-inflammatory properties are reflected upon differential molecular profiles of circulating EVs.

METHODS

Differences in circulating EV profiles were assessed using a combination of single vesicle analysis by Nanoparticle Tracking Analysis and flow cytometry, and proteomics.

RESULTS

We demonstrate, for the first time, that rivaroxaban-treated non-valvular atrial fibrillation (NVAF) patients (n=8) exhibit attenuated inflammation compared with matched warfarin controls (n=15). Circulating EV profiles were fundamentally altered. Moreover, quantitative proteomic analysis of enriched plasma EVs from six pooled biological donors per treatment group revealed a profound decrease in highly pro-inflammatory protein expression and complement factors, together with increased expression of negative regulators of inflammatory pathways. Crucially, a reduction in circulating levels of soluble P-selectin was observed in rivaroxaban-treated patients (compared with warfarin controls), which negatively correlated with the patient's time on treatment.

CONCLUSION

Collectively, these data demonstrate that NVAF patients anticoagulated with rivaroxaban (compared with warfarin) exhibit both a reduced pro-inflammatory state and evidence of reduced endothelial activation. These findings are of translational relevance toward characterizing the anti-inflammatory and cardiovascular-protective mechanisms associated with rivaroxaban therapy.

Routine Hematological Parameters May Be Predictors of COVID-19 Severity

To date, coronavirus disease 2019 (COVID-19) has affected over 100 million people globally. COVID-19 can present with a variety of different symptoms leading to manifestation of disease ranging from mild cases to a life-threatening condition requiring critical care-level support. At present, a rapid prediction of disease severity and critical care requirement in COVID-19 patients, in early stages of disease, remains an unmet challenge. Therefore, we assessed whether parameters from a routine clinical hematology workup, at the time of hospital admission, can be valuable predictors of COVID-19 severity and the requirement for critical care. Hematological data from the day of hospital admission (day of positive COVID-19 test) for patients with severe COVID-19 disease (requiring critical care during illness) and patients with non-severe disease (not requiring critical care) were acquired. The data were amalgamated and cleaned and modeling was performed. Using a decision tree model, we demonstrated that routine clinical hematology parameters are important predictors of COVID-19 severity. This proof-of-concept study shows that a combination of activated partial thromboplastin time, white cell count-to-neutrophil ratio, and platelet count can predict subsequent severity of COVID-19 with high sensitivity and specificity (area under ROC 0.9956) at the time of the patient's hospital admission. These data, pending further validation, indicate that a decision tree model with hematological parameters could potentially form the basis for a rapid risk stratification tool that predicts COVID-19 severity in hospitalized patients.

Heparin for Moderately Ill Patients with Covid-19

Background

Heparin, in addition to its anticoagulant properties, has anti-inflammatory and potential anti-viral effects, and may improve endothelial function in patients with Covid-19. Early initiation of therapeutic heparin could decrease the thrombo-inflammatory process, and reduce the risk of critical illness or death.

Methods

We randomly assigned moderately ill hospitalized ward patients admitted for Covid-19 with elevated D-dimer level to therapeutic or prophylactic heparin. The primary outcome was a composite of death, invasive mechanical ventilation, non-invasive mechanical ventilation or ICU admission. Safety outcomes included major bleeding. Analysis was by intention-to-treat.

Results

At 28 days, the primary composite outcome occurred in 37 of 228 patients (16.2%) assigned to therapeutic heparin, and 52 of 237 patients (21.9%) assigned to prophylactic heparin (odds ratio, 0.69; 95% confidence interval [CI], 0.43 to 1.10; p=0.12). Four patients (1.8%) assigned to therapeutic heparin died compared with 18 patients (7.6%) assigned to prophylactic heparin (odds ratio, 0.22; 95%-CI, 0.07 to 0.65). The composite of all-cause mortality or any mechanical ventilation occurred in 23 (10.1%) in the therapeutic heparin group and 38 (16.0%) in the prophylactic heparin group (odds ratio, 0.59; 95%-CI, 0.34 to 1.02). Major bleeding occurred in 2 patients (0.9%) with therapeutic heparin and 4 patients (1.7%) with prophylactic heparin (odds ratio, 0.52; 95%-CI, 0.09 to 2.85).

Conclusions

In moderately ill ward patients with Covid-19 and elevated D-dimer level, therapeutic heparin did not significantly reduce the primary outcome but decreased the odds of death at 28 days. Trial registration numbers: NCT04362085 ; NCT04444700.

Global reporting of pulmonary embolism-related deaths in the World Health Organization mortality database: Vital registration data from 123 countries

Introduction

Pulmonary embolism (PE) has not been accounted for as a cause of death contributing to cause‐specific mortality in global reports.

Methods

We analyzed global PE‐related mortality by focusing on the latest year available for each member state in the World Health Organization (WHO) mortality database, which provides age‐sex–specific aggregated mortality data transmitted by national authorities for each underlying cause of death. PE‐related deaths were defined by International Classification of Diseases, Tenth Revision codes for acute PE or nonfatal manifestations of venous thromboembolism (VTE). The 2001 WHO standard population served for standardization.

Results

We obtained data from 123 countries covering a total population of 2 602 561 422. Overall, 50 (40.6%) were European, 39 (31.7%) American, 13 (10.6%) Eastern Mediterranean, 13 (10.6%) Western Pacific, 3 (2.4%) Southeast Asian, and 2 (1.6%) African. Of 116 countries classifiable according to population income, 57 (49.1%) were high income, 42 (36.2%) upper‐middle income, 14 (12.1%) lower‐middle income, and 3 (2.6%) low income. A total of 18 726 382 deaths were recorded, of which 86 930 (0.46%) were attributed to PE. PE‐related mortality rate increased with age in most countries. The reporting of PE‐related deaths was heterogeneous, with an age‐standardized mortality rate ranging from 0 to 24 deaths per 100 000 population‐years. Income status only partially explained this heterogeneity.

Conclusions

Reporting of PE‐related mortality in official national vital registration was characterized by extreme heterogeneity across countries. These findings mandate enhanced efforts toward systematic and uniform coverage of PE‐related mortality and provides a case for full recognition of PE and VTE as a primary cause of death.

Coagulopathy of hospitalised COVID-19: A Pragmatic Randomised Controlled Trial of Therapeutic Anticoagulation versus Standard Care as a Rapid Response to the COVID-19 Pandemic (RAPID COVID COAG - RAPID Trial): A structured summary of a study protocol for a randomised controlled trial

Objectives

To determine the effect of therapeutic anticoagulation, with low molecular weight heparin (LMWH) or unfractionated heparin (UFH, high dose nomogram), compared to standard care in hospitalized patients admitted for COVID-19 with an elevated D-dimer on the composite outcome of intensive care unit (ICU) admission, non-invasive positive pressure ventilation, invasive mechanical ventilation or death up to 28 days.

Trial design

Open-label, parallel, 1:1, phase 3, 2-arm randomized controlled trial

Participants

The study population includes hospitalized adults admitted for COVID-19 prior to the development of critical illness. Excluded individuals are those where the bleeding risk or risk of transfusion would generally be considered unacceptable, those already therapeutically anticoagulated and those who have already have any component of the primary composite outcome. Participants are recruited from hospital sites in Brazil, Canada, Ireland, Saudi Arabia, United Arab Emirates, and the United States of America.

The inclusion criteria are:

Laboratory confirmed COVID-19 (diagnosis of SARS-CoV-2 via reverse transcriptase polymerase chain reaction as per the World Health Organization protocol or by nucleic acid based isothermal amplification) prior to hospital admission OR within first 5 days (i.e. 120 hours) after hospital admission;

Admitted to hospital for COVID-19;

One D-dimer value above the upper limit of normal (ULN) (within 5 days (i.e. 120 hours) of hospital admission) AND EITHER:

D-Dimer ≥2 times ULN OR

D-Dimer above ULN and Oxygen saturation ≤ 93% on room air;

> 18 years of age;

Informed consent from the patient (or legally authorized substitute decision maker).

The exclusion criteria are:

pregnancy;

hemoglobin <80 g/L in the last 72 hours;

platelet count <50 x 10⁹/L in the last 72 hours;

known fibrinogen <1.5 g/L (if testing deemed clinically indicated by the treating physician prior to the initiation of anticoagulation);

known INR >1.8 (if testing deemed clinically indicated by the treating physician prior to the initiation of anticoagulation);

patient already prescribed intermediate dosing of LMWH that cannot be changed (determination of what constitutes an intermediate dose is to be at the discretion of the treating clinician taking the local institutional thromboprophylaxis protocol for high risk patients into consideration);

patient already prescribed therapeutic anticoagulation at the time of screening [low or high dose nomogram UFH, LMWH, warfarin, direct oral anticoagulant (any dose of dabigatran, apixaban, rivaroxaban, edoxaban)];

patient prescribed dual antiplatelet therapy, when one of the agents cannot be stopped safely;

known bleeding within the last 30 days requiring emergency room presentation or hospitalization;

known history of a bleeding disorder of an inherited or active acquired bleeding disorder;

known history of heparin-induced thrombocytopenia;

known allergy to UFH or LMWH;

admitted to the intensive care unit at the time of screening;

treated with non-invasive positive pressure ventilation or invasive mechanical ventilation at the time of screening;

Imminent death according to the judgement of the most responsible physician;

enrollment in another clinical trial of antithrombotic therapy involving hospitalized patients.

Intervention and comparator

Intervention: Therapeutic dose of LMWH (dalteparin, enoxaparin, tinzaparin) or high dose nomogram of UFH. The choice of LMWH versus UFH will be at the clinician’s discretion and dependent on local institutional supply.

Comparator: Standard care [thromboprophylactic doses of LMWH (dalteparin, enoxaparin, tinzaparin, fondaparinux)] or UFH. Administration of LMWH, UFH or fondaparinux at thromboprophylactic doses for acutely ill hospitalized medical patients, in the absence of contraindication, is generally considered standard care.

Main outcomes

The primary composite outcome of ICU admission, non-invasive positive pressure ventilation, invasive mechanical ventilation or death at 28 days.

Secondary outcomes include (evaluated up to day 28):

All-cause death

Composite of ICU admission or all-cause death

Composite of mechanical ventilation or all-cause death

Major bleeding as defined by the ISTH Scientific and Standardization Committee (ISTH-SSC) recommendation;

Red blood cell transfusion (>1 unit);

Transfusion of platelets, frozen plasma, prothrombin complex concentrate, cryoprecipitate and/or fibrinogen concentrate;

Renal replacement therapy;

Hospital-free days alive;

ICU-free days alive;

Ventilator-free days alive;

Organ support-free days alive;

Venous thromboembolism (defined as symptomatic or incidental, suspected or confirmed via diagnostic imaging and/or electrocardiogram where appropriate);

Arterial thromboembolism (defined as suspected or confirmed via diagnostic imaging and/or electrocardiogram where appropriate);

Heparin induced thrombocytopenia;

Trajectories of COVID-19 disease-related coagulation and inflammatory biomarkers.

Randomisation

Randomisation will be stratified by site and age (>65 versus ≤65 years) using a 1:1 computer-generated random allocation sequence with variable block sizes. Randomization will occur within the first 5 days (i.e. 120 hours) of participant hospital admission. However, it is recommended that randomization occurs as early as possible after hospital admission. Central randomization using an interactive web response system will ensure allocation concealment.

Blinding (masking)

No blinding involved. This is an open-label trial.

Numbers to be randomised (sample size)

462 patients (231 per group) are needed to detect a 15% risk difference, from 50% in the control group to 35% in the experimental group, with power of 90% at a two-sided alpha of 0.05.

Trial Status

Protocol Version Number 1.4. Recruitment began on May 11^th, 2020. Recruitment is expected to be completed March 2022. Recruitment is ongoing.

Trial registration

ClinicalTrials.gov Identifier: NCT04362085

Date of Trial Registration: April 24, 2020

Full protocol

The full protocol is attached as an additional file, accessible from the Trials website (Additional file 1). In the interest of expediting dissemination of this material, the familiar formatting has been eliminated; this Letter serves as a summary of the key elements of the full protocol.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-021-05076-0.

COVID-19 induces a hyperactive phenotype in circulating platelets

Coronavirus Disease 2019 (COVID-19), caused by the novel Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), has affected over 30 million globally to date. Although high rates of venous thromboembolism and evidence of COVID-19-induced endothelial dysfunction have been reported, the precise aetiology of the increased thrombotic risk associated with COVID-19 infection remains to be fully elucidated. Therefore, we assessed clinical platelet parameters and circulating platelet activity in patients with severe and nonsevere COVID-19. An assessment of clinical blood parameters in patients with severe COVID-19 disease (requiring intensive care), patients with nonsevere disease (not requiring intensive care), general medical in-patients without COVID-19, and healthy donors was undertaken. Platelet function and activity were also assessed by secretion and specific marker analysis. We demonstrated that routine clinical blood parameters including increased mean platelet volume (MPV) and decreased platelet:neutrophil ratio are associated with disease severity in COVID-19 upon hospitalisation and intensive care unit (ICU) admission. Strikingly, agonist-induced ADP release was 30- to 90-fold higher in COVID-19 patients compared with hospitalised controls and circulating levels of platelet factor 4 (PF4), soluble P-selectin (sP-selectin), and thrombopoietin (TPO) were also significantly elevated in COVID-19. This study shows that distinct differences exist in routine full blood count and other clinical laboratory parameters between patients with severe and nonsevere COVID-19. Moreover, we have determined all COVID-19 patients possess hyperactive circulating platelets. These data suggest abnormal platelet reactivity may contribute to hypercoagulability in COVID-19 and confirms the role that platelets/clotting has in determining the severity of the disease and the complexity of the recovery path.

Harnessing Twitter to empower scientific engagement and communication: The ISTH 2020 virtual congress experience

As a result of the coronavirus disease 2019 pandemic, the International Society on Thrombosis and Haemostasis (ISTH), like many societies around the world, canceled their in-person hematology congress planned for Milan, Italy, in July 2020. As a result, the first virtual ISTH congress in the organisation's 51-year history was delivered, inviting free registration from across the globe. As part of the social media support, marketing, and scientific dissemination efforts for the virtual congress, the ISTH assembled a group of official Twitter Ambassadors, which represented the broad and diverse ISTH community. Ambassadors were tasked to tweet daily throughout the congress and to share their commentary on the hematology research being presented with the "#ISTH2020" hashtag. Ambassadors were also supported by Twitter activities from the two official ISTH-affiliated journals: the Journal of Thrombosis and Haemostasis (JTH) and Research and Practice in Thrombosis and Haemostasis (RPTH). In this forum and through the Twitter ambassadors' lens, we present the Twitter Ambassadors' experience, reflect on the impact of social media on the ISTH 2020 congress, and share this experience with the wider scientific community. Specifically, we report on the role of Twitter communication for virtual meetings, discuss the pros and cons of the virtual congress, and offer Twitter-related recommendations for future virtual or blended congresses. We conclude that the ISTH Twitter Ambassador program broadened social media engagement and offers a novel route to improve social connectivity in the virtual research congress setting.

Predicting bacteraemia in maternity patients using full blood count parameters: A supervised machine learning algorithm approach

INTRODUCTION

Bacteraemia in pregnancy and the post-partum period can lead to maternal and newborn morbidly. The purpose of this study was to use machine learning tools to identify if bacteraemia in pregnant or post-partum women could be predicted by full blood count (FBC) parameters other than the white cell count.

METHODS

The study was performed on 129 women with a positive blood culture (BC) for a clinically significant organism, who had a FBC taken at the same time. They were matched with controls who had a negative BC taken at the same time as a FBC. The data were split in to a training (70%) and test (30%) data set. Machine learning techniques such as recursive partitioning and classification and regression trees were used.

RESULTS

A neutrophil/lymphocyte ratio (NLR) of >20 was found to be the most clinically relevant and interpretable construct of the FBC result to predict bacteraemia. The diagnostic accuracy of NLR >20 to predict bacteraemia was then examined. Thirty-six of the 129 bacteraemia patients had a NLR >20, while only 223 of the 3830 controls had a NLR >20. This gave a sensitivity of 27.9% (95% CI 20.3-36.4), specificity of 94.1% (93.3-94.8), positive predictive value of 13.9% (10.6-17.9) and a negative predictive value (NPV) of 97.4% (97.2-97.7) when the prevalence of bacteraemia was 3%.

CONCLUSION

The NLR should be considered for use in routine clinical practice when assessing the FBC result in patients with suspected bacteraemia during pregnancy or in the post-partum period.

Which patients are at high risk of recurrent venous thromboembolism (deep vein thrombosis and pulmonary embolism)?

Recurrent venous thromboembolism (VTE, or deep vein thrombosis and pulmonary embolism) is associated with mortality and long-term morbidity. The circumstances in which an index VTE event occurred are crucial when personalized VTE recurrence risk is assessed. Patients who experience a VTE event in the setting of a transient major risk factor (such as surgery associated with general anesthesia for >30 minutes) are predicted to have a low VTE recurrence risk following discontinuation of anticoagulation, and limited-duration anticoagulation is generally recommended. In contrast, those patients whose VTE event occurred in the absence of risk factors or who have persistent risk factors have a higher VTE recurrence risk. Here, we review the literature surrounding VTE recurrence risk in a range of clinical conditions. We describe gender-specific risks, including VTE recurrence risk following hormone- and pregnancy-associated VTE events. Finally, we discuss how the competing impacts of VTE recurrence and bleeding have shaped international guideline recommendations.

Current opinion and emerging trends on the treatment, diagnosis, and prevention of pregnancy-associated venous thromboembolic disease: a review

Pregnancy associated venous thromboembolism (PA-VTE) is a leading cause of maternal morbidity and mortality worldwide. Despite the availability of international guidance on the prevention, diagnosis and treatment, practice differs between countries and clinical institutions. The evidence base in this area is limited due to the vulnerable population who are affected, with the majority of guidelines deriving their recommendations from experience in surgical and medical venous thromboembolic disease. This review includes best evidence in PA-VTE management, highlighting specific literature which supports current diagnosis, prevention, and treatment strategies. Additionally, we hope to demonstrate emerging trends in the field through discussion of ongoing trials designed to progress towards evidence-based practice in the context of PA-VTE.

Anticoagulation practice patterns in COVID-19: A global survey

Background

Best practice for prevention, diagnosis, and management of venous thromboembolism (VTE) in patients with coronavirus disease 2019 (COVID-19) is unknown due to limited published data in this population.

Objectives

We aimed to assess current global practice and experience in management of COVID-19-associated coagulopathy to identify information to guide prospective and randomized studies.

Methods

Physicians were queried about their current approach to prophylaxis, diagnosis, and treatment of VTE in patients with COVID-19 using an online survey tool distributed through multiple international organizations between April 10 and 14, 2020.

Results

Five hundred fifteen physicians from 41 countries responded. The majority of respondents (78%) recommended prophylactic anticoagulation for all hospitalized patients with COVID-19, with most recommending use of low-molecular-weight heparin or unfractionated heparin. Significant practice variation was found regarding the need for dose escalation of anticoagulation outside the setting of confirmed or suspected VTE. Respondents reported the use of bedside testing when unable to perform standard diagnostic imaging for diagnosis of VTE. Two hundred ninety-one respondents reported observing thrombotic complications in their patients, with 64% noting that the complication was pulmonary embolism. Of the 44% of respondents who estimated incidence of thrombosis in patients with COVID-19 in their hospital, estimates ranged widely from 1% to 50%. One hundred seventy-four respondents noted bleeding complications (34% minor bleeding, 14% clinically relevant nonmajor bleeding, and 12% major bleeding).

Conclusion

Well-designed epidemiologic studies are urgently needed to understand the incidence and risk factors of VTE and bleeding complications in patients with COVID-19. Randomized clinical trials addressing use of anticoagulation are also needed.

Understanding and Preventing Placenta-Mediated Pregnancy Complications

Placenta-mediated pregnancy complications are clinically important conditions and include preeclampsia, placental abruption, intrauterine growth restriction, and late fetal loss. Pathophysiology is complex, and may be linked to prothrombotic disorders such as antiphospholipid syndrome, whose understanding is still evolving. In this narrative review, we will present the latest evidence to better understand hemostatic mechanisms of preeclampsia, as well as in women with placenta-mediated pregnancy complications and inherited thrombophilia or antiphospholipid antibodies. Using four clinical scenarios, the mixed results of preventive efforts through the use of antithrombotic drugs (aspirin, heparin) will be discussed. We will also review knowledge gaps and ongoing research.

Comparative Platelet Releasate Proteomic Profiling of Acute Coronary Syndrome versus Stable Coronary Artery Disease

Upon activation, platelets release a host of soluble and vesicular signals, collectively termed the “platelet releasate” (PR). The contents of this PR play a significant role in haemostasis, inflammation, and pathologic sequelae. Despite this, proteomic studies investigating the PR in coronary artery disease have not been performed. Here, we undertook a comparative label-free quantitative (LFQ) proteomic profiling of the 1 U/ml thrombin-induced PR from 13 acute coronary syndrome vs. 14 stable angina pectoris patients using a tandem mass spectrometry approach. Data are available via ProteomeXchange with identifier PXD009356. 318 PR proteins were identified across both cohorts with 9 proteins found to be differentially released, including tetranectin (CLEC3B), protein disulfide-isomerase-A3 (PDIA3), coagulation factor V (F5), and fibronectin (FN1). Strikingly, these 9 differential proteins were all associated with the gene ontology cellular component term “extracellular vesicle” and reduced levels of EVs were detected in the corresponding plasma of ST-segment elevation myocardial infarction (STEMI) patients. Network analysis revealed 3 proteins either reduced (F5; FN1) or absent (CLEC3B) in the PR of STEMI patients that are strongly connected to both the clotting cascade and major druggable targets on platelets. This moderated proteomic signature may prove useful for non-invasive risk assessment of the progression of coronary artery disease. These data further contribute to the growing evidence-base of using the platelet releasate as a predictor of pathological state and disease severity.

Pathophysiology of the Venous Thromboembolism Risk in Preeclampsia

Preeclampsia complicates up to 8% of pregnancies and is a leading cause of fetomaternal morbidity andmortality. Treatment options are limited, with supportive care and delivery of the placenta representing the cornerstone of current management strategies. Derangements in blood coagulation are wellrecognised in this disorder and appear to favour an increased risk of venous thromboembolism among affected women. This risk appears to be most significant in the postpartum period. The mechanisms underlying this increased thrombosis risk remain to be fully elucidated although increased expression of procoagulant factors, endothelial dysfunction, attenuation of endogenous anticoagulant activity and increased platelet activity have been implicated in the prothrombotic tendency. Preeclampsia is also occasionally complicated by life-threatening haemorrhagic events and current evidence suggests that in some severe manifestations of this disease a coagulopathy with a clinical bleeding tendency may be the predominant haemostatic abnormality. Identifying affected women at significant risk of thrombosis and managing the competing thrombotic and haemorrhagic risks continue to be a significant clinical challenge. Derangements in blood coagulation are also implicated in the pathogenesis of preeclampsia; however, the role of antiplatelet or anticoagulant drugs in the prevention and treatment of this disorder remains a source of considerable debate. In addition, the potential role of specific haemostatic markers as diagnostic or screening tools for preeclampsia has also yet to be determined. Further characterisation of the underlying molecular mechanisms would likely be of major translational relevance and could provide insights into the pathogenesis of this disease as well as the associated haemostatic dysfunction.

Prevalence of postpartum venous thromboembolism risk factors in an Irish urban obstetric population

BACKGROUND

Obstetric venous thromboembolism (VTE) is a leading cause of maternal morbidity and mortality. A clear understanding of the burden of VTE risk at a population level is a prerequisite to effective prevention; however, existing data are limited.

OBJECTIVES

Describe the prevalence and patterns of VTE risk factors among postpartum women and consider the implications for VTE prevention practices.

METHOD

We undertook a cross-sectional study of prospectively collected data from sequential postpartum VTE risk assessments completed between January 2015 and December 2017 in the Rotunda Hospital, Dublin.

RESULTS

We analyzed postpartum VTE risk factors in a large unselected Irish urban obstetric cohort of 21 019 consecutively sampled women. This represents more than 90% of all women giving birth in a single institution over a 3-year period. The most common VTE risk factors related to maternal characteristics and delivery characteristics, including overweight and obesity (36%), age ≥35 (35%) and cesarean delivery (32%). More than three-quarters of women had at least 1 VTE risk factor (78%) and more than 40% had multiple (2 or more) VTE risk factors. One-fifth of women had no VTE risk factors before delivery, yet went on to develop VTE risk factors during delivery or in the postpartum period. Reflecting the differences in thromboprophylaxis thresholds internationally, the proportion of women who would have received a recommendation for postpartum thromboprophylaxis ranged from 7% to 37% under various clinical guidelines.

CONCLUSION

This study demonstrates the high prevalence of VTE risk factors among postpartum women. Postpartum VTE risk is highly individualized and complex.

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

Background

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

Objectives

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

Methods

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

Results

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

Conclusion

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

Proteomic Analysis Reveals a Strong Association of β-Catenin With Cadherin Adherens Junctions in Resting Human Platelets

It was previously demonstrated that the WNT/β-catenin pathway is present and active in platelets and established that the canonical WNT ligand, WNT-3a, suppresses platelet adhesion and activation. In nucleated cells, β-catenin, the key downstream effector of this pathway, is a dual function protein, regulating the coordination of gene transcription and cell-cell adhesion. The specific role of β-catenin in the anucleate platelet however remains elusive. Here, a label-free quantitative proteomic analysis of β-catenin immunoprecipitates from human platelets is performed and nine co-immunoprecipitating proteins are identified. Three of the co-immunoprecipitating proteins (α-catenin-1, cadherin-6, and β-catenin-interacting protein 1) are common to both resting and activated conditions. Bioinformatics analysis of proteomics data reveal a strong association of the dataset with both cadherin adherens junctions and regulators of WNT signaling. It is then verified that platelet β-catenin and cadherin-6 interact and that this interaction is regulated by the activation state of the platelet. Taken together, this proteomics study suggests a novel role for β-catenin in human platelets where it interacts with platelet cadherins and associated junctional proteins.

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

OBJECTIVES

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

DESIGN

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

SETTING

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

PARTICIPANTS

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

RESULTS

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

CONCLUSION

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

Liver stiffness and thrombin generation in compensated cirrhosis

BACKGROUND

Decompensated cirrhosis is associated with coagulation abnormalities that can increase the risk of thrombosis and bleeding. It is unclear precisely when these abnormalities arise and whether they are exacerbated as compensated cirrhosis progresses. Transient elastography using FibroScan generates liver stiffness measurements (LSM) that associate with portal hypertension, clinical outcomes and provides prognostic information at an earlier stage than traditional liver function scores eg, MELD score.

OBJECTIVE

To characterize thrombin generation in patients with compensated cirrhosis and to determine whether parameters of coagulation change throughout compensated cirrhosis, staged using LSM.

PATIENTS/METHODS

Blood samples were collected from well-compensated cirrhotic patients n = 61, All Child Pugh A stage) attending the Mater Misericordiae University Hospital, Ireland. Comprehensive clinical staging of liver disease, including LSM, was performed. Tissue Factor-stimulated thrombin generation was measured by calibrated automated thrombography.

RESULTS

Using LSM to stage well-compensated cirrhotic patients, we demonstrate a significant decrease in the rate of propagation, the rate of attenuation, and total thrombin generation as LSM increase. LSM correlated with endogenous thrombin potential, peak thrombin generation, the rate of propagation, and the rate of attenuation. This association between thrombin generation and LSM was still evident in sub-analyses excluding patients with ongoing alcohol use, active HCV infection, or a history of decompensation. In contrast, there was no significant correlation between thrombin generation, prothrombin times, Child-Pugh scores, or MELD scores.

CONCLUSION

Liver stiffness measurements identify differences in parameters of thrombin generation within a cohort of compensated cirrhotic patients before changes in clotting times occur.